Science.gov

Sample records for acetamide phosphonic acid

  1. Isopropyl methyl phosphonic acid (IMPA)

    Integrated Risk Information System (IRIS)

    Isopropyl methyl phosphonic acid ( IMPA ) ; CASRN 1832 - 54 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assess

  2. Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite

    NASA Technical Reports Server (NTRS)

    Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

    1992-01-01

    Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

  3. Phosphonic acid based exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1995-01-01

    An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

  4. Phosphonic acid based exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1995-09-12

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

  5. Developmental Toxicity of Perfluorinated Phosphonic Acids in Mice

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a third member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. PFPAs are used primarily as a surfactant defoaming agent in pesticide production. Re...

  6. Synthesis and characterization of phosphonate ester and phosphonic acid containing polymers and blends

    NASA Astrophysics Data System (ADS)

    Tamber, Harinder Singh

    1997-12-01

    Vinylbenzylphosphonate ester (VBP) was homopolymerized and copolymerized with methyl methacrylate and the reactivity ratio of this pair of monomers was calculated from Finneman-Ross and Kelen-Tudos methods. These methods provided identical values, which are rsb1 (VBP) = 1.23 and rsb2(MMA) = 0.43. The phosphonate ester group, -P = O(OEt)sb2; in VBP and poly(VBP-MMA) copolymers was hydrolysed to phosphonic acid, -P = O(OH)sb2; at room temperature to obtain vinylbenzylphosphonic acid (VBPa) and poly(VBPa-MMA) copolymers. sp1H, sp{13}C & sp{31}P NMR spectroscopy, DSC and FTIR were used to monitor the hydrolysis of these phosphorylated monomers and polymers. The glass transition temperature of PVBP was 13sp°C as compared to 198sp°C of PVBPa. The phosphoryl group in the parent polymers acts as a self plasticizing agent resulting in lower glass transition temperature, on the other hand inter and intra hydrogen bonding results in broad and high Tsbg in these hydrolysed polymers. VBP was also polymerized with BisGMA or TEGDM to low conversions. These oligomers were tested in vitro as potential adhesive materials for dental/enamel and composite resins. The phosphonate esters containing polymers show substantial capacity to dissolve the heavy metal salts, e.g., UOsb2(NO)sb3.6Hsb2O and thus provides radiopaque polymers. Excessive sorption of water lead to phase separation and, hence, loss of radiopacity. Thus, an alternate method of synthesis of radiopaque polymers is also described in which radiopacifying agent is covalently linked to polymer backbone. Styryldiphenylbismuth was prepared by the reaction of diphenylbismuthchloride and Grignard of p-bromostyrene, but some other by-products such as triphenylbismuth, distyrylphenyl bismoth were also obtained as revealed by reverse phase HPLC and the yield of the reaction was low. Iodinated monomers VBTIsb3 and IEMIsb3 were prepared by reacting VBC or IEM to triiodophenol in high yields. Decomposition kinetic analysis was done by

  7. Phosphonic Acid-Functionalized Polyurethane Dispersions with Improved Adhesion Properties.

    PubMed

    Breucker, Laura; Landfester, Katharina; Taden, Andreas

    2015-11-11

    A facile route to phosphorus-functionalized polyurethane dispersions (P-PUDs) with improved adhesion properties is presented. (Bis)phosphonic acid moieties serve as adhesion promoting sites that are covalently attached via an end-capping reaction to isocyanate-reactive polyurethane particles under aqueous conditions. The synthetic approach circumvents solubility issues, offers great flexibility in terms of polyurethane composition, and allows for the synthesis of semicrystalline systems with thermomechanical response due to reversible physical cross-linking. Differential scanning calorimetry (DSC) is used to investigate the effect of functionalization on the semicrystallinity. The end-capping conversion was determined via inductively-coupled plasma optical emission spectroscopy (ICP-OES) and was surprisingly found to be almost independent of the stoichiometry of reaction, suggesting an adsorption-dominated process. Particle charge detection (PCD) experiments reveal that a dense surface coverage of phosphonic acid groups can be attained and that, at high functionalization degrees, the phosphonic adhesion moieties are partially dragged inside the colloidal P-PUD particle. Quartz crystal microbalance with dissipation (QCMD) investigations conducted with hydroxyapatite (HAP) and stainless steel sensors as model surfaces show a greatly enhanced affinity of the aqueous P-PUDs and furthermore indicate polymer chain rearrangements and autonomous film formation under wet conditions. Due to their facile synthesis, significantly improved adhesion, and variable film properties, P-PUD systems such as the one described here are believed to be of great interest for multiple applications, e.g., adhesives, paints, anticorrosion, or dentistry. PMID:26491881

  8. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  9. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  10. 40 CFR 721.10370 - Phosphonic acid, p-octyl-, lanthanum (3+) salt (2:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid, p-octyl-, lanthanum... New Uses for Specific Chemical Substances § 721.10370 Phosphonic acid, p-octyl-, lanthanum (3+) salt... substance identified as phosphinic acid, p-octyl-, lanthanum (3+) salt (2:1) (PMN P-10-99; CAS No....

  11. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1996-01-01

    An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

  12. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1994-01-01

    An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene disphosphonic acid with styrene, acrylonitrile and divinylbenzene.

  13. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1994-01-25

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 9 figures.

  14. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1996-07-23

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

  15. 40 CFR 721.10243 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, bis(2-chloroethyl) ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid, P- ethyl]-, bis(2... Specific Chemical Substances § 721.10243 Phosphonic acid, P- ethyl]-, bis(2-chloroethyl) ester. (a... phosphonic acid, P- ethyl]-, bis(2-chloroethyl) ester (PMN P-09-193; CAS No. 55088-28-3) is subject...

  16. 40 CFR 721.10243 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, bis(2-chloroethyl) ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid, P- ethyl]-, bis(2... Specific Chemical Substances § 721.10243 Phosphonic acid, P- ethyl]-, bis(2-chloroethyl) ester. (a... phosphonic acid, P- ethyl]-, bis(2-chloroethyl) ester (PMN P-09-193; CAS No. 55088-28-3) is subject...

  17. 40 CFR 721.10243 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, bis(2-chloroethyl) ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid, P- ethyl]-, bis(2... Specific Chemical Substances § 721.10243 Phosphonic acid, P- ethyl]-, bis(2-chloroethyl) ester. (a... phosphonic acid, P- ethyl]-, bis(2-chloroethyl) ester (PMN P-09-193; CAS No. 55088-28-3) is subject...

  18. Effects of Perfluorinated Phosphonic Acid Exposure during pregnancy in the mouse

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. These chemicals have recently been detected in the environment, particularly in surface wa...

  19. Biosynthesis of Phosphonic and Phosphinic Acid Natural Products

    PubMed Central

    Metcalf, William W.; van der Donk, Wilfred A.

    2009-01-01

    Natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. Recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. This review discusses the commonalities and differences in the molecular logic that lies behind the biosynthesis of these compounds. The current knowledge regarding the metabolic pathways and enzymes involved in the production of a number of natural products, including the approved antibiotic fosfomycin, the widely used herbicide phosphinothricin, and the clinical candidate for treatment of malaria FR900098, is presented. Many of the enzymes involved in the biosynthesis of these compounds catalyze chemically and biologically unprecedented transformations and a wealth of new biochemistry has been revealed through their study. These studies have also suggested new strategies for natural product discovery. PMID:19489722

  20. Graphene phosphonic acid as an efficient flame retardant.

    PubMed

    Kim, Min-Jung; Jeon, In-Yup; Seo, Jeong-Min; Dai, Liming; Baek, Jong-Beom

    2014-03-25

    We report the preparation of graphene phosphonic acid (GPA) via a simple and versatile method and its use as an efficient flame retardant. In order to covalently attach phosphorus to the edges of graphene nanoplatelets, graphite was ball-milled with red phosphorus. The cleavage of graphitic C-C bonds during mechanochemical ball-milling generates reactive carbon species, which react with phosphorus in a sealed ball-mill crusher to form graphene phosphorus. Subsequent opening of the crusher in air moisture leads to violent oxidation of graphene phosphorus into GPA (highest oxidation state). The GPA is readily dispersible in many polar solvents, including neutral water, allowing for solution (spray) coating for high-performance, nontoxic flame-retardant applications. PMID:24575902

  1. Determination of perfluoroalkyl carboxylic, sulfonic, and phosphonic acids in food.

    PubMed

    Ullah, Shahid; Alsberg, Tomas; Vestergren, Robin; Berger, Urs

    2012-11-01

    A sensitive and accurate method was developed and validated for simultaneous analysis of perfluoroalkyl carboxylic acids, sulfonic acids, and phosphonic acids (PFPAs) at low picograms per gram concentrations in a variety of food matrices. The method employed extraction with acetonitrile/water and cleanup on a mixed-mode co-polymeric sorbent (C8 + quaternary amine) using solid-phase extraction. High-performance liquid chromatographic separation was achieved on a C18 column using a mobile phase gradient containing 5 mM 1-methyl piperidine for optimal chromatographic resolution of PFPAs. A quadrupole time-of-flight high-resolution mass spectrometer operating in negative ion mode was used as detector. Method detection limits were in the range of 0.002 to 0.02 ng g(-1) for all analytes. Sample preparation (extraction and cleanup) recoveries at a spiking level of 0.1 ng g(-1) to a baby food composite were in the range of 59 to 98 %. A strong matrix effect was observed in the analysis of PFPAs in food extracts, which was tentatively assigned to sorption of PFPAs to the injection vial in the solvent-based calibration standard. The method was successfully applied to a range of different food matrices including duplicate diet samples, vegetables, meat, and fish samples. PMID:22955674

  2. Characterization of phosphonic acid binding to zinc oxide

    SciTech Connect

    Hotchkiss, Peter J.; Malicki, Michał; Giordano, Anthony J.; Armstrong, Neal R.; Marder, Seth R.

    2011-01-24

    Radio Frequency (RF) sputter-deposited zinc oxide (ZnO) films have been modified with alkylphosphonic acids in order to study both the binding of the phosphonic acid (PA) group to the ZnO surface and the packing of the alkyl chain. The characterization of these PA-modified ZnO substrates by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRRAS), atomic force microscopy (AFM) and contact angle measurements is presented herein. The surface modification procedure is straightforward and was adapted from earlier work. XPS analysis shows that oxygen plasma (OP) treatment creates reactive oxygen species on the surface of ZnO, allowing for a more robust binding of PAs to the ZnO surface. IRRAS analysis indicates that octadecylphosphonic acid binds to the ZnO surface in a predominantly tridentate fashion, forming dense, well-packed monolayers with alkyl chains in a fully anti-conformation. AFM and contact angle measurements indicate good surface coverage of the PAs with little to no multilayer formation.

  3. Copper-catalyzed α-amination of phosphonates and phosphine oxides: a direct approach to α-amino phosphonic acids and derivatives.

    PubMed

    McDonald, Stacey L; Wang, Qiu

    2014-02-10

    A direct approach to important α-amino phosphonic acids and its derivatives has been developed by using copper-catalyzed electrophilic amination of α-phosphonate zincates with O-acyl hydroxylamines. This amination provides the first example of CN bond formation which directly introduces acyclic and cyclic amines to the α-position of phosphonates in one step. The reaction is readily promoted at room temperature with as little as 0.5 mol % of catalyst, and demonstrates high efficiency on a broad substrate scope. PMID:24474326

  4. Phosphonic Acids for Interfacial Engineering of Transparent Conductive Oxides.

    PubMed

    Paniagua, Sergio A; Giordano, Anthony J; Smith, O'Neil L; Barlow, Stephen; Li, Hong; Armstrong, Neal R; Pemberton, Jeanne E; Brédas, Jean-Luc; Ginger, David; Marder, Seth R

    2016-06-22

    Transparent conducting oxides (TCOs), such as indium tin oxide and zinc oxide, play an important role as electrode materials in organic-semiconductor devices. The properties of the inorganic-organic interface-the offset between the TCO Fermi level and the relevant transport level, the extent to which the organic semiconductor can wet the oxide surface, and the influence of the surface on semiconductor morphology-significantly affect device performance. This review surveys the literature on TCO modification with phosphonic acids (PAs), which has increasingly been used to engineer these interfacial properties. The first part outlines the relevance of TCO surface modification to organic electronics, surveys methods for the synthesis of PAs, discusses the modes by which they can bind to TCO surfaces, and compares PAs to alternative organic surface modifiers. The next section discusses methods of PA monolayer deposition, the kinetics of monolayer formation, and structural evidence regarding molecular orientation on TCOs. The next sections discuss TCO work-function modification using PAs, tuning of TCO surface energy using PAs, and initiation of polymerizations from TCO-tethered PAs. Finally, studies that examine the use of PA-modified TCOs in organic light-emitting diodes and organic photovoltaics are compared. PMID:27227316

  5. Investigation of the extraction properties of dibutyl ester of dibutoxymethane phosphonic acid

    SciTech Connect

    Herrmann, E.; Hala, J.

    1983-01-01

    The extraction properties of the dibutyl ester of dibutoxymethane phosphonic acid (DBDBMP), an analog of TBP with a P-C bond, were shown to be similar to those of TBP except for hydrolysis of DBDBMP in acidic solutions. The formation of acidic organophosphorus compounds during hydrolysis of DBDBMP was confirmed by /sup 31/P-N.M.R. measurements. 4 figures, 1 table.

  6. 40 CFR 721.10412 - Phosphonic acid ester (generic) (P-07-706).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... appropriate gas/vapor cartridges (organic vapor, acid gas, or substance-specific); NIOSH-certified powered air... (organic vapor, acid gas, or substance-specific); NIOSH-certified powered air-purifying respirator with a... Specific Chemical Substances § 721.10412 Phosphonic acid ester (generic) (P-07-706). (a) Chemical...

  7. 40 CFR 721.10412 - Phosphonic acid ester (generic) (P-07-706).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... appropriate gas/vapor cartridges (organic vapor, acid gas, or substance-specific); NIOSH-certified powered air... (organic vapor, acid gas, or substance-specific); NIOSH-certified powered air-purifying respirator with a... Specific Chemical Substances § 721.10412 Phosphonic acid ester (generic) (P-07-706). (a) Chemical...

  8. 40 CFR 721.10412 - Phosphonic acid ester (generic) (P-07-706).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... appropriate gas/vapor cartridges (organic vapor, acid gas, or substance-specific); NIOSH-certified powered air... (organic vapor, acid gas, or substance-specific); NIOSH-certified powered air-purifying respirator with a... Specific Chemical Substances § 721.10412 Phosphonic acid ester (generic) (P-07-706). (a) Chemical...

  9. Discovery of phosphonic acid natural products by mining the genomes of 10,000 actinomycetes.

    PubMed

    Ju, Kou-San; Gao, Jiangtao; Doroghazi, James R; Wang, Kwo-Kwang A; Thibodeaux, Christopher J; Li, Steven; Metzger, Emily; Fudala, John; Su, Joleen; Zhang, Jun Kai; Lee, Jaeheon; Cioni, Joel P; Evans, Bradley S; Hirota, Ryuichi; Labeda, David P; van der Donk, Wilfred A; Metcalf, William W

    2015-09-29

    Although natural products have been a particularly rich source of human medicines, activity-based screening results in a very high rate of rediscovery of known molecules. Based on the large number of natural product biosynthetic genes in microbial genomes, many have proposed "genome mining" as an alternative approach for discovery efforts; however, this idea has yet to be performed experimentally on a large scale. Here, we demonstrate the feasibility of large-scale, high-throughput genome mining by screening a collection of over 10,000 actinomycetes for the genetic potential to make phosphonic acids, a class of natural products with diverse and useful bioactivities. Genome sequencing identified a diverse collection of phosphonate biosynthetic gene clusters within 278 strains. These clusters were classified into 64 distinct groups, of which 55 are likely to direct the synthesis of unknown compounds. Characterization of strains within five of these groups resulted in the discovery of a new archetypical pathway for phosphonate biosynthesis, the first (to our knowledge) dedicated pathway for H-phosphinates, and 11 previously undescribed phosphonic acid natural products. Among these compounds are argolaphos, a broad-spectrum antibacterial phosphonopeptide composed of aminomethylphosphonate in peptide linkage to a rare amino acid N(5)-hydroxyarginine; valinophos, an N-acetyl l-Val ester of 2,3-dihydroxypropylphosphonate; and phosphonocystoximate, an unusual thiohydroximate-containing molecule representing a new chemotype of sulfur-containing phosphonate natural products. Analysis of the genome sequences from the remaining strains suggests that the majority of the phosphonate biosynthetic repertoire of Actinobacteria has been captured at the gene level. This dereplicated strain collection now provides a reservoir of numerous, as yet undiscovered, phosphonate natural products. PMID:26324907

  10. Discovery of phosphonic acid natural products by mining the genomes of 10,000 actinomycetes

    PubMed Central

    Ju, Kou-San; Gao, Jiangtao; Doroghazi, James R.; Wang, Kwo-Kwang A.; Thibodeaux, Christopher J.; Li, Steven; Metzger, Emily; Fudala, John; Su, Joleen; Zhang, Jun Kai; Lee, Jaeheon; Cioni, Joel P.; Evans, Bradley S.; Hirota, Ryuichi; Labeda, David P.; van der Donk, Wilfred A.; Metcalf, William W.

    2015-01-01

    Although natural products have been a particularly rich source of human medicines, activity-based screening results in a very high rate of rediscovery of known molecules. Based on the large number of natural product biosynthetic genes in microbial genomes, many have proposed “genome mining” as an alternative approach for discovery efforts; however, this idea has yet to be performed experimentally on a large scale. Here, we demonstrate the feasibility of large-scale, high-throughput genome mining by screening a collection of over 10,000 actinomycetes for the genetic potential to make phosphonic acids, a class of natural products with diverse and useful bioactivities. Genome sequencing identified a diverse collection of phosphonate biosynthetic gene clusters within 278 strains. These clusters were classified into 64 distinct groups, of which 55 are likely to direct the synthesis of unknown compounds. Characterization of strains within five of these groups resulted in the discovery of a new archetypical pathway for phosphonate biosynthesis, the first (to our knowledge) dedicated pathway for H-phosphinates, and 11 previously undescribed phosphonic acid natural products. Among these compounds are argolaphos, a broad-spectrum antibacterial phosphonopeptide composed of aminomethylphosphonate in peptide linkage to a rare amino acid N5-hydroxyarginine; valinophos, an N-acetyl l-Val ester of 2,3-dihydroxypropylphosphonate; and phosphonocystoximate, an unusual thiohydroximate-containing molecule representing a new chemotype of sulfur-containing phosphonate natural products. Analysis of the genome sequences from the remaining strains suggests that the majority of the phosphonate biosynthetic repertoire of Actinobacteria has been captured at the gene level. This dereplicated strain collection now provides a reservoir of numerous, as yet undiscovered, phosphonate natural products. PMID:26324907

  11. Thermal phase diagram of acetamide-benzoic acid and benzoic acid-phthalimide binary systems for solar thermal applications

    NASA Astrophysics Data System (ADS)

    Kumar, Rohitash; Kumar, Ravindra; Dixit, Ambesh

    2016-05-01

    Thermal properties of Acetamide (AM) - Benzoic acid (BA) and Benzoic acid (BA) - Phthalimide (PM) binary eutectic systems are theoretically calculated using thermodynamic principles. We found that the binary systems of AM-BA at 67.6 : 32.4 molar ratio, BA-PM at 89.7 : 10.3 molar ratio form eutectic mixtures with melting temperatures ~ 54.5 °C and 114.3 °C respectively. Calculated latent heat of fusion for these eutectic mixtures are 191 kJ/kg and 146.5 kJ/kg respectively. These melting temperatures and heat of fusions of these eutectic mixtures make them suitable for thermal energy storage applications in solar water heating and solar cooking systems.

  12. 40 CFR 721.10244 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, 2-[bis(2- chloroethoxy)phosphinyl]ethyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid, P- ethyl]-, 2- ethyl... New Uses for Specific Chemical Substances § 721.10244 Phosphonic acid, P- ethyl]-, 2- ethyl 2... substance identified as phosphonic acid, P- ethyl]-, 2- ethyl 2-chloroethyl ester (PMN P-09-195; CAS...

  13. 40 CFR 721.10244 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, 2-[bis(2- chloroethoxy)phosphinyl]ethyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid, P- ethyl]-, 2- ethyl... New Uses for Specific Chemical Substances § 721.10244 Phosphonic acid, P- ethyl]-, 2- ethyl 2... substance identified as phosphonic acid, P- ethyl]-, 2- ethyl 2-chloroethyl ester (PMN P-09-195; CAS...

  14. 40 CFR 721.10244 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, 2-[bis(2- chloroethoxy)phosphinyl]ethyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid, P- ethyl]-, 2- ethyl... New Uses for Specific Chemical Substances § 721.10244 Phosphonic acid, P- ethyl]-, 2- ethyl 2... substance identified as phosphonic acid, P- ethyl]-, 2- ethyl 2-chloroethyl ester (PMN P-09-195; CAS...

  15. 40 CFR 721.6075 - Phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substance identified as phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester (PMN P-95-168) is... paragraph. (1) Recordkeeping. Recordkeeping requirements as specified in § 721.125 (a) through (h) are... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES...

  16. 40 CFR 721.6075 - Phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-tetrakis(1-methylethyl) ester. 721.6075 Section 721.6075 Protection of Environment ENVIRONMENTAL PROTECTION...-methylethyl) ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester (PMN P-95-168)...

  17. 40 CFR 721.6075 - Phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-tetrakis(1-methylethyl) ester. 721.6075 Section 721.6075 Protection of Environment ENVIRONMENTAL PROTECTION...-methylethyl) ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester (PMN P-95-168)...

  18. Multifunctional water-soluble molecular capsules based on p-phosphonic acid calix[5]arene.

    PubMed

    Martin, Adam D; Boulos, Ramiz A; Hubble, Lee J; Hartlieb, Karel J; Raston, Colin L

    2011-07-14

    p-Phosphonic acid calix[5]arene forms molecular capsules in water based on two of the molecules, which can be loaded with carboplatin using intense shearing, and attached to single wall carbon nano-tubes. Spin coating of the capsules onto a substrate affords 2 nm fibres of stacked calixarenes, with the self-assembly understood using molecular modelling. PMID:21637889

  19. Luminescent ruthenium(II) bipyridyl-phosphonic acid complexes: pH dependent photophysical behavior and quenching with divalent metal ions

    SciTech Connect

    Montalti, M.; Wadhwa, S.; Kim, W.Y.; Kipp, R.A.; Schmehl, R.H.

    2000-01-10

    The synthesis, redox behavior, and photophysical properties of a series of Ru(II) bipyridyl complexes having diimine ligands with phosphonate and phosphonic acid substituents are presented. The phosphonate-containing ligands examined include diethyl 4-(2,2{prime}-bipyrid-4-yl)benzylphosphonate (bpbzp), diethyl 4(2,2{prime}-bipyrid-4-yl)-phenylphosphonate (bppp), and 4,4{prime}-(diethyl phosphonato)-2,2{prime}bipyridine (bpdp), and the [(bpy){sub 2}Ru(L)](PF{sub 6}){sub 2} complexes of both the diethyl phosphonate and the phosphonic acid were prepared. The Ru(III/II) potentials are more positive for the phosphonate complexes than for the phosphonic acids, and the first reduction is localized on the phosphonate-containing ligand for the bppp and bpdp complexes. The first reduction of the phosphonic acid complexes is at more negative potentials and cannot be distinguished from bpy reduction. For the bppp and bpdp complexes luminescence arises from a Ru(d{pi}) {r{underscore}arrow} bpy-phosphonate ({pi}*) MLCT state; the phosphonic acid complexes luminesce at higher energies from a MLCT state not clearly isolated on one ligand. Iron(III) and copper(II) complex with and very efficiently quench the luminescence of all the phosphonic acid complexes in nonaqueous solvents. The quenching mechanism is discussed on the basis of luminescence decay and picosecond transient absorption measurements.

  20. Synthesis of homo and hetero metal-phosphonate frameworks from bi-functional aminomethylphosphonic acid

    SciTech Connect

    Samanamu, Christian R.; Zamora, Elena Nicole; Montchamp, Jean-Luc; Richards, Anne F.

    2008-06-15

    The reaction between aminomethylphosphonic acid (ampa) and the metal salts of Zn, Cd, Hg, Pb, Ag, and Cu afforded seven metal-phosphonate polymers with unique structural features and includes the synthesis of a bimetallic metal-organic framework (Cu/Ag). The characterization of these metal phosphonates is reported by means of infrared spectroscopy, {sup 1}H-NMR, {sup 31}P-NMR, X-ray crystallography, energy dispersive X-ray (EDX), and thermogravimetric analysis (TGA). Individual structural features are compared based on the preferred coordination mode of ampa and the geometrical requirements for each metallic center that manipulates the structural motif. - Graphical abstract: The synthesis and characterization of polymeric metal phosphonates featuring zinc, cadmium, mercury, lead, and silver phosphonate are described from the reactions of the bi-funtional aminomethylphosphonic acid with the metal precursor in aqueous conditions. These previously undescribed polymers display unusual structural features and include the synthesis of a bimetallic metal-organic framework (Cu/Ag)

  1. Spatially Modulating Interfacial Properties of Transparent Conductive Oxides: Patterning Work Function with Phosphonic Acid Self-Assembled Monolayers

    SciTech Connect

    Knesting, Kristina M.; Hotchkiss, Peter J.; MacLeod, Bradley A.; Marder, Seth R.; Ginger, David S.

    2011-09-29

    The interface between an organic semiconductor and a transparent conducting oxide is crucial to the performance of organic optoelectronics. We use microcontact printing to pattern pentafluorobenzyl phosphonic acid self-assembled monolayers (SAMs) on indium tin oxide (ITO). We obtain high-fidelity patterns with sharply defined edges and with large work function contrast (comparable to that obtained from phosphonic acid SAMs deposited from solution).

  2. Synthesis and proteinase inhibitory properties of diphenyl phosphonate analogues of aspartic and glutamic acids.

    PubMed

    Hamilton, R; Walker, B; Walker, B J

    1998-07-01

    The synthesis of diphenyl phosphonate analogues of aspartic and glutamic acid, and their inhibitory activity against S. aureus V8 protease and granzyme B, is described. The study has revealed difficulties with protecting group compatibility in the synthesis of these analogues. Two analogues, Acetyl. AspP (OPh)2 and Acetyl.GluP (OPh)2 were found to function as irreversible inactivators of V8 proteinase, yet exhibit no activity against granzyme B. PMID:9873408

  3. Flower-like supramolecular self-assembly of phosphonic acid appended naphthalene diimide and melamine

    PubMed Central

    Bhosale, Rajesh S; Al Kobaisi, Mohammad; Bhosale, Sidhanath V.; Bhargava, Suresh; Bhosale, Sheshanath V.

    2015-01-01

    Diverse supramolecular assemblies ranging from nanometres to micrometers of small aromatic π-conjugated functional molecules have attracted enormous research interest in light of their applications in optoelectronics, chemosensors, nanotechnology, biotechnology and biomedicines. Here we study the mechanism of the formation of a flower-shaped supramolecular structure of phosphonic acid appended naphthalene diimide with melamine. The flower-shaped assembly formation was visualised by scanning electron microscope (SEM) and transmission electron microscopy (TEM) imaging, furthermore, XRD and DLS used to determined mode of aggregation. Characteristically, phosphonic acid-substituted at imide position of NDIs possess two important properties resulting in the formation of controlled flower-like nanostructures: (i) the aromatic core of the NDI which is designed to optimize the dispersive interactions (π-π stacking and van der Waals interactions) between the cores within a construct and (ii) phosphonic acid of NDI interact with malamine through molecular recognition i.e. strong hydrogen-bonding (H-bonding). We believe such arrangements prevent crystallization and favour the directional growth of flower-like nanostructure in 3D fashion. These works demonstrate that complex self-assembly can indeed be attained through hierarchical non-covalent interactions of two components. Furthermore, flower-like structures built from molecular recognition by these molecules indicate their potential in other fields if combined with other chemical entities. PMID:26416382

  4. Structure and Order of Phosphonic Acid-Based Self-Assembled Monolayers on Si(100)

    PubMed Central

    Dubey, Manish; Weidner, Tobias; Gamble, Lara J.; Castner, David G.

    2010-01-01

    Organophosphonic acid self-assembled monolayers (SAMs) on oxide surfaces have recently seen increased use in electrical and biological sensor applications. The reliability and reproducibility of these sensors require good molecular organization in these SAMs. In this regard, packing, order and alignment in the SAMs is important, as it influences the electron transport measurements. In this study, we examine the order of hydroxyl- and methyl- terminated phosphonate films deposited onto silicon oxide surfaces by the tethering by aggregation and growth method using complementary, state-of-art surface characterization tools. Near edge x-ray absorption fine structure (NEXAFS) spectroscopy and in situ sum frequency generation (SFG) spectroscopy are used to study the order of the phosphonate SAMs in vacuum and under aqueous conditions, respectively. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry results show that these samples form chemically intact monolayer phosphonate films. NEXAFS and SFG spectroscopy showed that molecular order exists in the octadecylphosphonic acid and 11-hydroxyundecylphosphonic acid SAMs. The chain tilt angles in these SAMs were approximately 37° and 45°, respectively. PMID:20735054

  5. Flower-like supramolecular self-assembly of phosphonic acid appended naphthalene diimide and melamine

    NASA Astrophysics Data System (ADS)

    Bhosale, Rajesh S.; Al Kobaisi, Mohammad; Bhosale, Sidhanath V.; Bhargava, Suresh; Bhosale, Sheshanath V.

    2015-09-01

    Diverse supramolecular assemblies ranging from nanometres to micrometers of small aromatic π-conjugated functional molecules have attracted enormous research interest in light of their applications in optoelectronics, chemosensors, nanotechnology, biotechnology and biomedicines. Here we study the mechanism of the formation of a flower-shaped supramolecular structure of phosphonic acid appended naphthalene diimide with melamine. The flower-shaped assembly formation was visualised by scanning electron microscope (SEM) and transmission electron microscopy (TEM) imaging, furthermore, XRD and DLS used to determined mode of aggregation. Characteristically, phosphonic acid-substituted at imide position of NDIs possess two important properties resulting in the formation of controlled flower-like nanostructures: (i) the aromatic core of the NDI which is designed to optimize the dispersive interactions (π-π stacking and van der Waals interactions) between the cores within a construct and (ii) phosphonic acid of NDI interact with malamine through molecular recognition i.e. strong hydrogen-bonding (H-bonding). We believe such arrangements prevent crystallization and favour the directional growth of flower-like nanostructure in 3D fashion. These works demonstrate that complex self-assembly can indeed be attained through hierarchical non-covalent interactions of two components. Furthermore, flower-like structures built from molecular recognition by these molecules indicate their potential in other fields if combined with other chemical entities.

  6. Atomistic Simulations of Perfluoro Phosphonic and Phosphinic Acid Membranes and Comparisons to Nafion

    SciTech Connect

    Idupulapati, Nagesh B.; Devanathan, Ramaswami; Dupuis, Michel

    2011-03-31

    We used classical molecular dynamics (MD) simulations to investigate the nanoscale morphology and proton transport properties of perfluoro phosphonic (FPA) and phosphinic acid (FPA-I) membranes as they are being considered for use in low temperature fuel cells. We systematically investigated these properties as a function of the hydration level. The changes in nanostructure, in transport dynamics of water and hydronium ions, and in water network percolation were extracted from MD simulations and compared with Nafion. Phosphonic and phosphinic acid moieties in FPA and FPA-I, have lower acidity than sulfonic acid in Nafion, yet the diffusion of water was observed to be faster in FPA and FPA-I than in Nafion, particularly at low hydration levels. However this did not give rise to notable differences in hydronium ion diffusion and water network percolation for these membranes over Nafion. Similar observations were also reported by our group recently in a study of perfluoro-sulfonyl imide membranes carrying stronger super-acids than sulfonic acid of Nafion. These findings together suggest no strong apparent correlation between the acidity strength of the functional acid groups and the dynamics of water and hydronium ions in hydrated polymer electrolyte membranes (PEMs) with similar fluorocarbon backbones and acidic group-carrying side chains. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  7. Novel alpha-hydroxy phosphonic acids via castor oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydroxy fatty acids (HFAs) have found a number of uses in today’s market, with uses ranging from materials to pharmaceuticals. Castor oil has served as a versatile HFA; its principle component, ricinoleic acid, can be isolated from castor oil and has been modified extensively for a number of applica...

  8. Characterizing mixed phosphonic acid ligand capping on CdSe/ZnS quantum dots using ligand exchange and NMR spectroscopy.

    PubMed

    Davidowski, Stephen K; Lisowski, Carmen E; Yarger, Jeffery L

    2016-03-01

    The ligand capping of phosphonic acid functionalized CdSe/ZnS core-shell quantum dots (QDs) was investigated with a combination of solution and solid-state (31) P nuclear magnetic resonance (NMR) spectroscopy. Two phosphonic acid ligands were used in the synthesis of the QDs, tetradecylphosphonic acid and ethylphosphonic acid. Both alkyl phosphonic acids showed broad liquid and solid-state (31) P NMR resonances for the bound ligands, indicative of heterogeneous binding to the QD surface. In order to quantify the two ligand populations on the surface, ligand exchange facilitated by phenylphosphonic acid resulted in the displacement of the ethylphosphonic acid and tetradecylphosphonic acid and allowed for quantification of the free ligands using (31) P liquid-state NMR. After washing away the free ligand, two broad resonances were observed in the liquids' (31) P NMR corresponding to the alkyl and aromatic phosphonic acids. The washed samples were analyzed via solid-state (31) P NMR, which confirmed the ligand populations on the surface following the ligand exchange process. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26639792

  9. Exciton-blocking phosphonic acid-treated anode buffer layers for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Zimmerman, Jeramy D.; Song, Byeongseop; Griffith, Olga; Forrest, Stephen R.

    2013-12-01

    We demonstrate significant improvements in power conversion efficiency of bilayer organic photovoltaics by replacing the exciton-quenching MoO3 anode buffer layer with an exciton-blocking benzylphosphonic acid (BPA)-treated MoO3 or NiO layer. We show that the phosphonic acid treatment creates buffers that block up to 70% of excitons without sacrificing the hole extraction efficiency. Compared to untreated MoO3 anode buffers, BPA-treated NiO buffers exhibit a ˜ 25% increase in the near-infrared spectral response in diphenylanilo functionalized squaraine (DPSQ)/C60-based bilayer devices, increasing the power conversion efficiency under 1 sun AM1.5G simulated solar illumination from 4.8 ± 0.2% to 5.4 ± 0.3%. The efficiency can be further increased to 5.9 ± 0.3% by incorporating a highly conductive exciton blocking bathophenanthroline (BPhen):C60 cathode buffer. We find similar increases in efficiency in two other small-molecule photovoltaic systems, indicating the generality of the phosphonic acid-treated buffer approach to enhance exciton blocking.

  10. An ATR-FTIR study of different phosphonic acids in aqueous solution.

    PubMed

    Zenobi, María C; Luengo, Carina V; Avena, Marcelo J; Rueda, Elsa H

    2008-07-01

    An ATR-FIR study of the vibrational spectra of 1-hydroxyethane-1,1'-diphosphonic acid (HEDP), nitrilotris(methylenephosphonic acid) (NTMP) and N,N-bis(2-hydroxyethyl)aminomethylphosphonic acid (BHAMP) in aqueous solution is presented. The study was performed in the range of pH from 5 to 9, and bands assignments are given in the 2000-890 cm(-1) range. However, as phosphonates display bands due to the PO stretching vibration mainly in the 900-1200 cm(-1) range, the study is focused in this midinfrared region, which shows important changes as the pH changes, specially the nu(POH) at approximately 925 cm(-1) and nu(PO(3)(2-)) at approximately 970 cm(-1) vibrations. IR analyses give also evidences for the zwitterionic nature of BHAMP and NTMP in solution with a strong indication that the zwitterion in both compounds remains intact throughout the pH range investigated. The successive protonation steps with the decrease of pH were evidenced in the IR spectra of the three studied phosphonates. PMID:17826311

  11. An ATR-FTIR study of different phosphonic acids in aqueous solution

    NASA Astrophysics Data System (ADS)

    Zenobi, María C.; Luengo, Carina V.; Avena, Marcelo J.; Rueda, Elsa H.

    2008-07-01

    An ATR-FIR study of the vibrational spectra of 1-hydroxyethane-1,1'-diphosphonic acid (HEDP), nitrilotris(methylenephosphonic acid) (NTMP) and N, N-bis(2-hydroxyethyl)aminomethylphosphonic acid (BHAMP) in aqueous solution is presented. The study was performed in the range of pH from 5 to 9, and bands assignments are given in the 2000-890 cm -1 range. However, as phosphonates display bands due to the P sbnd O stretching vibration mainly in the 900-1200 cm -1 range, the study is focused in this midinfrared region, which shows important changes as the pH changes, specially the ν(P sbnd OH) at ˜925 cm -1 and ν(PO 32-) at ˜970 cm -1 vibrations. IR analyses give also evidences for the zwitterionic nature of BHAMP and NTMP in solution with a strong indication that the zwitterion in both compounds remains intact throughout the pH range investigated. The successive protonation steps with the decrease of pH were evidenced in the IR spectra of the three studied phosphonates.

  12. An ATR-FTIR study of different phosphonic acids adsorbed onto boehmite

    NASA Astrophysics Data System (ADS)

    Zenobi, María C.; Luengo, Carina V.; Avena, Marcelo J.; Rueda, Elsa H.

    2010-04-01

    An ATR-FTIR study of the vibrational spectra of N,N-bis(2-hydroxyethyl) aminomethylphosphonic acid (BHAMP), 1-hydroxyethane-1,1'-diphosphonic acid (HEDP) and nitrilotris(methylenephosphonic acid) (NTMP) adsorbed onto boehmite is presented. The study was performed in the pH range from 5 to 9, and bands assignments are given in the 1200-900 cm -1 wavenumber range, where the bands associated with various P-O(H) vibrations can be found. The three phosphonic acids adsorb onto boehmite by forming inner-sphere surface complexes. ATR-FTIR data indicates the presence of both protonated and deprotonated mononuclear surface species. In all cases, the surface-bound ions undergo protonation reactions as pH is decreased. The results are in good agreement with previously proposed surface complexation models.

  13. An ATR-FTIR study of different phosphonic acids adsorbed onto boehmite.

    PubMed

    Zenobi, María C; Luengo, Carina V; Avena, Marcelo J; Rueda, Elsa H

    2010-04-01

    An ATR-FTIR study of the vibrational spectra of N,N-bis(2-hydroxyethyl) aminomethylphosphonic acid (BHAMP), 1-hydroxyethane-1,1'-diphosphonic acid (HEDP) and nitrilotris(methylenephosphonic acid) (NTMP) adsorbed onto boehmite is presented. The study was performed in the pH range from 5 to 9, and bands assignments are given in the 1200-900 cm(-1) wavenumber range, where the bands associated with various P-O(H) vibrations can be found. The three phosphonic acids adsorb onto boehmite by forming inner-sphere surface complexes. ATR-FTIR data indicates the presence of both protonated and deprotonated mononuclear surface species. In all cases, the surface-bound ions undergo protonation reactions as pH is decreased. The results are in good agreement with previously proposed surface complexation models. PMID:20129815

  14. The antiviral activity of tetrazole phosphonic acids and their analogues.

    PubMed Central

    Hutchinson, D W; Naylor, M

    1985-01-01

    5-(Phosphonomethyl)-1H-tetrazole and a number of related tetrazoles have been prepared and their effects on the replication of Herpes Simplex Viruses-1 and -2 have been investigated as well as their abilities to inhibit the DNA polymerases induced by these viruses and the RNA transcriptase activity of influenza virus A. Contrary to an earlier report, 5-(phosphonomethyl)-1H-tetrazole was not an efficient inhibitor of the replication of HSV-1 and HSV-2 in tissue culture. Analogues of 5-(phosphonomethyl)-1H-tetrazole were also devoid of significant antiviral activity. Only 5-(phosphonomethyl)-1H-tetrazole and 5-(thiophosphonomethyl)-1H-tetrazole inhibited the influenza virus transcriptase, and both were more effective as inhibitors than phosphonoacetic acid under the same conditions. The DNA polymerases induced by HSV-1 and HSV-2 were inhibited slightly by 5-(phosphonomethyl)-1H-tetrazole and to a lesser extent by its N-ethyl analogue and 3-(phosphonomethyl)-1H-1,2,4-triazole. None of these compounds were as effective as phosphonoacetic acid. 5-(Thiophosphonomethyl)-1H-tetrazole was a better inhibitor of the DNA polymerase induced by HSV-1 than 5-(phosphonomethyl)-1H-tetrazole. PMID:2417198

  15. Thermal stability and ordering study of long- and short-alkyl chain phosphonic acid multilayers.

    PubMed

    de Pauli, Muriel; Prado, Mariana de Castro; Matos, Matheus Josue Souza; Fontes, Giselle Nogueira; Perez, Carlos Alberto; Mazzoni, Mario Sergio Carvalho; Neves, Bernardo Ruegger Almeida; Malachias, Angelo

    2012-10-30

    Long-range order evolution of self-assembled phosphonic acid multilayers as a function of temperature is studied here for two molecules with different alkyl chain length. By using synchrotron conventional diffraction, distinct order configurations are retrieved on phosphonic acid multilayers and their thermodynamic behavior monitored by energy-dispersive diffraction. This later technique allows us to observe the system behavior near order-disorder temperatures, as well as to determine the most stable configurations in the range from room temperature up to 120 °C. Planar order is also addressed by wide-angle X-ray scattering (WAXS) transmission experiments. Order parameter phase diagrams are built based on the experimental results, showing the dominant configuration at each temperature. The multilayer molecular long-range order retrieved from the experiments is corroborated by first principles calculations based on the Density Functional Theory. The bulk configurations depicted in this work are produced by molecule-molecule interactions and allow for future comparisons with the behavior of ordered molecules in few-monolayers configurations, commonly used in organic devices, where the presence of surfaces and interfaces strongly affects the molecule packing. PMID:23009090

  16. PM-IRRAS Determination of Molecular Orientation of Phosphonic Acid Self-Assembled Monolayers on Indium Zinc Oxide.

    PubMed

    Sang, Lingzi; Mudalige, Anoma; Sigdel, Ajaya K; Giordano, Anthony J; Marder, Seth R; Berry, Joseph J; Pemberton, Jeanne E

    2015-05-26

    Self-assembled monolayers (SAMs) of phosphonic acids (PAs) on transparent conductive oxide (TCO) surfaces can facilitate improvement in TCO/organic semiconductor interface properties. When ordered PA SAMs are formed on oxide substrates, interface dipole and electronic structure are affected by the functional group properties, orientation, and binding modes of the modifiers. Choosing octylphosphonic acid (OPA), F13-octylphosphonic acid (F13OPA), pentafluorophenyl phosphonic acid (F5PPA), benzyl phosphonic acid (BnPA), and pentafluorobenzyl phosphonic acid (F5BnPA) as a representative group of modifiers, we report polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) of binding and molecular orientation on indium-doped zinc oxide (IZO) substrates. Considerable variability in molecular orientation and binding type is observed with changes in PA functional group. OPA exhibits partially disordered alkyl chains but on average the chain axis is tilted ∼57° from the surface normal. F13OPA tilts 26° with mostly tridentate binding. The F5PPA ring is tilted 23° from the surface normal with a mixture of bidentate and tridentate binding; the BnPA ring tilts 31° from normal with a mixture of bidentate and tridentate binding, and the F5BnPA ring tilts 58° from normal with a majority of bidentate with some tridenate binding. These trends are consistent with what has been observed previously for the effects of fluorination on orientation of phosphonic acid modifiers. These results from PM-IRRAS are correlated with recent results on similar systems from near-edge X-ray absorption fine structure (NEXAFS) and density functional theory (DFT) calculations. Overall, these results indicate that both surface binding geometry and intermolecular interactions play important roles in dictating the orientation of PA modifiers on TCO surfaces. This work also establishes PM-IRRAS as a routine method for SAM orientation determination on complex oxide substrates

  17. Conserved biosynthetic pathways for phosalacine, bialaphos and newly discovered phosphonic acid natural products.

    PubMed

    Blodgett, Joshua A V; Zhang, Jun Kai; Yu, Xiaomin; Metcalf, William W

    2016-01-01

    Natural products containing phosphonic or phosphinic acid functionalities often display potent biological activities with applications in medicine and agriculture. The herbicide phosphinothricin-tripeptide (PTT) was the first phosphinate natural product discovered, yet despite numerous studies, questions remain surrounding key transformations required for its biosynthesis. In particular, the enzymology required to convert phosphonoformate to carboxyphosphonoenolpyruvate and the mechanisms underlying phosphorus methylation remain poorly understood. In addition, the model for non-ribosomal peptide synthetase assembly of the intact tripeptide product has undergone numerous revisions that have yet to be experimentally tested. To further investigate the biosynthesis of this unusual natural product, we completely sequenced the PTT biosynthetic locus from Streptomyces hygroscopicus and compared it with the orthologous cluster from Streptomyces viridochromogenes. We also sequenced and analyzed the closely related phosalacine (PAL) biosynthetic locus from Kitasatospora phosalacinea. Using data drawn from the comparative analysis of the PTT and PAL pathways, we also evaluate three related recently discovered phosphonate biosynthetic loci from Streptomyces sviceus, Streptomyces sp. WM6386 and Frankia alni. Our observations address long-standing biosynthetic questions related to PTT and PAL production and suggest that additional members of this pharmacologically important class await discovery. PMID:26328935

  18. Conserved biosynthetic pathways for phosalacine, bialaphos and newly discovered phosphonic acid natural products

    PubMed Central

    Blodgett, Joshua A. V; Zhang, Jun Kai; Yu, Xiaomin; Metcalf, William W.

    2015-01-01

    Natural products containing phosphonic or phosphinic acid functionalities often display potent biological activities with applications in medicine and agriculture. The herbicide phosphinothricin-tripeptide (PTT) was the first phosphinate natural product discovered, yet despite numerous studies, questions remain surrounding key transformations required for its biosynthesis. In particular, the enzymology required to convert phosphonoformate to carboxyphosphonoenolpyruvate and the mechanisms underlying phosphorus-methylation remain poorly understood. In addition, the model for NRPS assembly of the intact tripeptide product has undergone numerous revisions that have yet to be experimentally tested. To further investigate the biosynthesis of this unusual natural product, we completely sequenced the PTT biosynthetic locus from Streptomyces hygroscopicus and compared it to the orthologous cluster from Streptomyces viridochromogenes. We also sequenced and analysed the closely related phosalacine (PAL) biosynthetic locus from Kitasatospora phosalacinea. Using data drawn from the comparative analysis of the PTT and PAL pathways, we also evaluate three related recently discovered phosphonate biosynthetic loci from Streptomyces sviceus, Streptomyces sp. WM6386 and Frankia alni. Our observations address long-standing biosynthetic questions related to PTT and PAL production and suggest that additional members of this pharmacologically important class await discovery. PMID:26328935

  19. Solid-State NMR Characterization of Mixed Phosphonic Acid Ligand Binding and Organization on Silica Nanoparticles.

    PubMed

    Davidowski, Stephen K; Holland, Gregory P

    2016-04-01

    As ligand functionalization of nanomaterials becomes more complex, methods to characterize the organization of multiple ligands on surfaces is required. In an effort to further the understanding of ligand-surface interactions, a combination of multinuclear ((1)H, (29)Si, (31)P) and multidimensional solid-state nuclear magnetic resonance (NMR) techniques was utilized to characterize the phosphonic acid functionalization of fumed silica nanoparticles using methylphosphonic acid (MPA) and phenylphosphonic acid (PPA). (1)H → (29)Si cross-polarization (CP)-magic angle spinning (MAS) solid-state NMR was used to selectively detect silicon atoms near hydrogen atoms (primarily surface species); these results indicate that geminal silanols are preferentially depleted during the functionalization with phosphonic acids. (1)H → (31)P CP-MAS solid-state NMR measurements on the functionalized silica nanoparticles show three distinct resonances shifted upfield (lower ppm) and broadened compared to the resonances of the crystalline ligands. Quantitative (31)P MAS solid-state NMR measurements indicate that ligands favor a monodentate binding mode. When fumed silica nanoparticles were functionalized with an equal molar ratio of MPA and PPA, the MPA bound the nanoparticle surface preferentially. Cross-peaks apparent in the 2D (1)H exchange spectroscopy (EXSY) NMR measurements of the multiligand sample at short mixing times indicate that the MPA and PPA are spatially close (≤5 Å) on the surface of the nanostructure. Furthermore, (1)H-(1)H double quantum-single quantum (DQ-SQ) back-to-back (BABA) 2D NMR spectra further confirmed that MPA and PPA are strongly dipolar coupled with observation of DQ intermolecular contacts between the ligands. DQ experimental buildup curves and simulations indicate that the average distance between MPA and PPA is no further than 4.2 ± 0.2 Å. PMID:26914738

  20. Tuning the molecular order of C60 functionalized phosphonic acid monolayers.

    PubMed

    Rumpel, Armin; Novak, Michael; Walter, Johannes; Braunschweig, Björn; Halik, Marcus; Peukert, Wolfgang

    2011-12-20

    Mixed self-assembled monolayers (SAM) of alkyl phosphonic acids and C(60) functionalized octadecyl phosphonic acids (C(60)C(18)-PA) are deposited on alumina substrates from solution and are shown to form well-ordered structures with an insulating layer of alkyl chains and a semiconducting layer that comprises mainly C(60). Such an ordered structure is a necessity for the application of SAMs in organic transistors but is difficult to obtain since C(60)C(18)-PA without additional support do self-assemble in dense packaging but not in a well-ordered fashion. To avoid disordering of the SAM and to gain a better control of the interfacial properties we have investigated the stabilizing effects of fluorinated dodecyl phosphonic acids (FC(12)-PA) on the C(60)C(18)-PA monolayer. Vibrational sum-frequency (SFG) spectroscopy, ellipsometry, X-ray photoelectron spectroscopy, and electrical measurements were applied to study the mixed monolayers. Here, we make use of the differently labeled PA to determine surface coverages and molecular properties of the two species independently. Adsorption of FC(12)-PA gives rise to vibrational bands at 1344 cm(-1) and 1376 cm(-1) in SFG spectra, while a pronounced vibrational band centered at 1465 cm(-1) is attributable to C(60) vibrations. The coexistence of the bands is indicative for the presence of a mixed monolayer that is composed of both molecular species. Furthermore, a pronounced maximum in SFG intensity of the C(60) band is observed for SAMs, which are deposited from solutions with ~75% C(60)C(18)-PA and ~25% FC(12)-PA. The intensity maximum originates from successful stabilization of C(60) modified C(60)C(18)-PA by FC(12)-PA and a significantly improved molecular order. Conclusions from SFG spectra are corroborated by electric measurements that show best performance at these concentrations. Our results provide new information on the morphology and composition of C(60) modified SAMs and establish a route to fabricate well

  1. A report on emergent uranyl binding phenomena by an amidoxime phosphonic acid co-polymer.

    PubMed

    Abney, C W; Das, S; Mayes, R T; Kuo, L-J; Wood, J; Gill, G; Piechowicz, M; Lin, Z; Lin, W; Dai, S

    2016-09-14

    The development of technology to harvest the uranium dissolved in seawater would enable access to vast quantities of this critical metal for nuclear power generation. Amidoxime polymers are the most promising platforms for achieving this separation, yet the design of advanced adsorbents is hindered by uncertainty regarding the uranium binding mode. In this work we use XAFS to investigate the uranium coordination environment in an amidoxime-phosphonic acid copolymer adsorbent. In contrast to the binding mode predicted computationally and from small molecule studies, a cooperative chelating model is favoured, attributable to emergent behavior resulting from inclusion of amidoxime in the polymer. Samples exposed to seawater also display a feature consistent with a μ(2)-oxo-bridged transition metal, suggesting the formation of an in situ specific binding site. These findings challenge long held assumptions and provide new opportunities for the design of advanced adsorbent materials. PMID:27507226

  2. A report on emergent uranyl binding phenomena by an amidoxime phosphonic acid co-polymer

    DOE PAGESBeta

    Abney, C. W.; Das, S.; Mayes, R. T.; Kuo, L. -J.; Wood, J.; Gill, G.; Piechowicz, M.; Lin, Z.; Lin, W.; Dai, S.

    2016-08-01

    Development of technology to harvest the uranium dissolved in seawater would enable access to vast quantities of this critical metal for nuclear power generation. Amidoxime polymers are the most promising platform for achieving this separation, yet design of advanced adsorbents is hindered by uncertainty regarding the uranium binding mode. In this work we use XAFS to investigate the uranium coordination environment in an amidoxime-phosphonic acid copolymer adsorbent. In contrast to the binding mode predicted computationally and from small molecule studies, a cooperative chelating model is favoured, attributable to emergent behavior resulting from inclusion of amidoxime in a polymer. Samples exposedmore » to seawater also display a feature consistent with a 2-oxo-bridged transition metal, suggesting formation of an in situ specific binding site. As a result, these findings challenge long held assumptions and provide new opportunities for the design of advanced adsorbent materials.« less

  3. Redox reaction between amino-(3,4-dihydroxyphenyl)methyl phosphonic acid and dopaquinone is responsible for the apparent inhibitory effect on tyrosinase.

    PubMed

    Gasowska, Beata; Wojtasek, Hubert; Hurek, Józef; Drag, Marcin; Nowak, Kornel; Kafarski, Paweł

    2002-08-01

    Amino-(3,4-dihydroxyphenyl)methyl phosphonic acid, the phosphonic analog of 3,4-dihydroxyphenylglycine, had been previously reported as a potent inhibitor of tyrosinase. The mechanism of the apparent enzyme inhibition by this compound has now been established. Amino-(3,4-dihydroxyphenyl)methyl phosphonic acid turned out to be a substrate and was oxidized to o-quinone, which evolved to a final product identified as 3,4-dihydroxybenzaldehyde, the same as for 3,4-dihydroxyphenylglycine. Monohydroxylated compounds (amino-(3-hydroxyphenyl)methyl phosphonic acid and amino-(4-hydroxyphenyl)methyl phosphonic acid) were not oxidized, neither was 4-hydroxy-l-phenylglycine. However, the relatively high Km for amino-(3,4-dihydroxyphenyl)methyl phosphonic acid (0.52 mm) indicated that competitive inhibition could not entirely explain the previously reported strong inhibitory effect (Ki = 50 and 97 micro m for tyrosine and 3-(3,4-dihydroxyphenyl)alanine (Dopa) as substrates, respectively). Neither was the enzyme covalently inactivated to a significant degree. Spectroscopic and electrochemical analysis of the oxidation of a mixture of Dopa and the inhibitor demonstrated that the phosphonic compound reduced dopaquinone back to Dopa, thus diminishing and delaying the formation of dopachrome. This produces an apparent strong inhibitory effect when the reaction is monitored spectrophotometrically at 475 nm. In this peculiar case Dopa acts as a redox shuttle mediating the oxidation of the shorter phosphonic homolog. Decomposition of the phosphonic o-quinone to 3,4-dihydroxybenzaldehyde drives the reaction against the slightly unfavorable difference in redox potentials. PMID:12180986

  4. Characterizing the molecular order of phosphonic acid self-assembled monolayers on indium tin oxide surfaces.

    PubMed

    Losego, Mark D; Guske, Joshua T; Efremenko, Alina; Maria, Jon-Paul; Franzen, Stefan

    2011-10-01

    Self-assembled monolayers (SAMs) of alkanephosphonic acids with chain lengths between 8 and 18 carbon units were formed on thin films of indium tin oxide (ITO) sputter-deposited on silicon substrates with 400 nm thermally grown SiO(2). The silicon substrates, while not intended for use in near-IR or visible optics applications, do provide smooth surfaces that permit systematic engineering of grain size and surface roughness as a function of the sputter pressure. Argon sputter pressures from 4 to 20 mTorr show systematic changes in surface morphology ranging from smooth, micrometer-sized grain structures to <50 nm grains with 3× higher surface roughness. Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy experiments are conducted for alkanephosphonic acids deposited on these wide range of ITO surfaces to evaluate the effects of these morphological features on monolayer ordering. Results indicate that long-chain SAMs are more highly ordered, and have a smaller tilt angle, than short-chain SAMs. Surprisingly, the 1-octadecyl phosphonic acids maintain their order as the lateral grain dimensions of the ITO surface shrink to ∼50 nm. It is only when the ITO surface roughness becomes greater than the SAM chain length (∼15 Å) that SAMs are observed to become relatively disordered. PMID:21863828

  5. Assembly of phosphonic acids on GaN and AlGaN

    NASA Astrophysics Data System (ADS)

    Simpkins, B. S.; Hong, S.; Stine, R.; Mäkinen, A. J.; Theodore, N. D.; Mastro, M. A.; Eddy, C. R., Jr.; Pehrsson, P. E.

    2010-01-01

    Self-assembled monolayers of octadecylphosphonic acid and 16-phosphonohexadecanoic acid (PHDA) were formed on the semiconductor substrates gallium nitride (GaN) and aluminium gallium nitride (AlGaN). The presence of the molecular layers was verified through x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Structural information was acquired with infrared spectroscopy which verified the bonding orientation of the carboxyl-containing PHDA. The impact of the molecular layers on the channel conductivity and the surface electronic structure of an AlGaN/GaN heterostructure was measured. Our results indicate that pinning of the surface Fermi level prohibits modification of the channel conductivity by the layer. However, a surface dipole of ~0.8 eV is present and associated with both phosphonic acid layers. These results are of direct relevance to field-effect-based biochemical sensors and metal-semiconductor contact formation for this system and provide a fundamental basis for further applications of GaN and AlGaN technology in the fields of biosensing and microelectronics.

  6. pH dependence of methyl phosphonic acid, dipicolinic acid, and cyanide by surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Farquharson, Stuart; Gift, Alan; Maksymiuk, Paul; Inscore, Frank E.; Smith, Wayne W.

    2004-03-01

    U.S. and Coalition forces fighting terrorism in Afghanistan and Iraq must consider a wide range of attack scenarios in addition to car bombings. Among these is the intentional poisoning of water supplies to obstruct military operations. To counter such attacks, the military is developing portable analyzers that can identify and quantify potential chemical agents in water supplies at microgram per liter concentrations within 10 minutes. To aid this effort we have been investigating the value of a surface-enhanced Raman spectroscopy based portable analyzer. In particular we have been developing silver-doped sol-gels to generate SER spectra of chemical agents and their hydrolysis products. Here we present SER spectra of methyl phosphonic acid and cyanide as a function of pH, an important factor affecting quantitation measurements, which to our knowledge has not been examined. In addition, dipicolinic acid, a chemical signature associated with anthrax-causing spores, is also presented.

  7. Copper-catalyzed asymmetric synthesis of tertiary α-hydroxy phosphonic acid derivatives with in situ generated nitrosocarbonyl compounds as the oxygen source.

    PubMed

    Maji, Biplab; Yamamoto, Hisashi

    2014-12-22

    α-Hydroxy phosphonic acids and their derivatives are highly bioactive structural motifs. It is now reported that these compounds can be accessed through the copper-catalyzed direct α-oxidation of β-ketophosphonates using in situ generated nitrosocarbonyl compounds as an electrophilic oxygen source. These reactions proceeded in high yields (up to 95 %) and enantioselectivities (up to >99 % ee) for both cyclic as well as acyclic substrates. This method was also applied for the synthesis of α,β-dihydroxy phosphonates and β-amino-α-hydroxy phosphonates. PMID:25348199

  8. Substitution of the phosphonic acid and hydroxamic acid functionalities of the DXR inhibitor FR900098: an attempt to improve the activity against Mycobacterium tuberculosis.

    PubMed

    Andaloussi, Mounir; Lindh, Martin; Björkelid, Christofer; Suresh, Surisetti; Wieckowska, Anna; Iyer, Harini; Karlén, Anders; Larhed, Mats

    2011-09-15

    Two series of FR900098/fosmidomycin analogs were synthesized and evaluated for MtDXR inhibition and Mycobacterium tuberculosis whole-cell activity. The design rationale of these compounds involved the exchange of either the phosphonic acid or the hydroxamic acid part for alternative acidic and metal-coordinating functionalities. The best inhibitors provided IC(50) values in the micromolar range, with a best value of 41 μM. PMID:21824775

  9. Transcriptional and cellular responses of the green alga Chlamydomonas reinhardtii to perfluoroalkyl phosphonic acids.

    PubMed

    Sanchez, David; Houde, Magali; Douville, Mélanie; De Silva, Amila O; Spencer, Christine; Verreault, Jonathan

    2015-03-01

    Perfluoroalkyl phosphonic acids (PFPAs), a new class of perfluoroalkyl substances used primarily in the industrial sector as surfactants, were recently detected in surface water and wastewater treatment plant effluents. Toxicological effects of PFPAs have as yet not been investigated in aquatic organisms. The objective of the present study was to evaluate the effects of perfluorooctylphosphonic acid (C8-PFPA) and perfluorodecylphosphonic acid (C10-PFPA) exposure (31-250μg/L) on Chlamydomonas reinhardtii using genomic (qRT-PCR), biochemical (reactive oxygen species production (ROS) and lipid peroxidation), and physiological (cellular viability) indicators. After 72h of exposure, no differences were observed in cellular viability for any of the two perfluorochemicals. However, increase in ROS concentrations (36% and 25.6% at 125 and 250μg/L, respectively) and lipid peroxidation (35.5% and 35.7% at 125 and 250μg/L, respectively) was observed following exposure to C10-PFPA. C8-PFPA exposure did not impact ROS production and lipid peroxidation in algae. To get insights into the molecular response and modes of action of PFPA toxicity, qRT-PCR-based assays were performed to analyze the transcription of genes related to antioxidant responses including superoxide dismutase (SOD-1), glutathione peroxidase (GPX), catalase (CAT), glutathione S-transferase (GST), and ascorbate peroxidase (APX I). Genomic analyses revealed that the transcription of CAT and APX I was up-regulated for all the C10-PFPA concentrations. In addition, PFPAs were quantified in St. Lawrence River surface water samples and detected at concentrations ranging from 250 to 850pg/L for C8-PFPA and 380 to 650pg/L for C10-PFPA. This study supports the prevalence of PFPAs in the aquatic environment and suggests potential impacts of PFPA exposure on the antioxidant defensive system in C. reinhardtii. PMID:25621396

  10. Etching of Crystalline ZnO Surfaces upon Phosphonic Acid Adsorption: Guidelines for the Realization of Well-Engineered Functional Self-Assembled Monolayers.

    PubMed

    Ostapenko, Alexandra; Klöffel, Tobias; Eußner, Jens; Harms, Klaus; Dehnen, Stefanie; Meyer, Bernd; Witte, Gregor

    2016-06-01

    Functionalization of metal oxides by means of covalently bound self-assembled monolayers (SAMs) offers a tailoring of surface electronic properties such as their work function and, in combination with its large charge carrier mobility, renders ZnO a promising conductive oxide for use as transparent electrode material in optoelectronic devices. In this study, we show that the formation of phosphonic acid-anchored SAMs on ZnO competes with an unwanted chemical side reaction, leading to the formation of surface precipitates and severe surface damage at prolonged immersion times of several days. Combining atomic force microscopy (AFM), X-ray diffraction (XRD), and thermal desorption spectroscopy (TDS), the stability and structure of the aggregates formed upon immersion of ZnO single crystal surfaces of different orientations [(0001̅), (0001), and (101̅0)] in phenylphosphonic acid (PPA) solution were studied. By intentionally increasing the immersion time to more than 1 week, large crystalline precipitates are formed, which are identified as zinc phosphonate. Moreover, the energetics and the reaction pathway of this transformation have been evaluated using density functional theory (DFT), showing that zinc phosphonate is thermodynamically more favorable than phosphonic acid SAMs on ZnO. Precipitation is also found for phosphonic acids with fluorinated aromatic backbones, while less precipitation occurs upon formation of SAMs with phenylphosphinic anchoring units. By contrast, no precipitates are formed when PPA monolayer films are prepared by sublimation under vacuum conditions, yielding smooth surfaces without noticeable etching. PMID:27159837

  11. Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents.

    PubMed

    Deka, Juti Rani; Liu, Chia-Ling; Wang, Tzu-Hua; Chang, Wei-Chieh; Kao, Hsien-Ming

    2014-08-15

    Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π-π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles. PMID:25010459

  12. Self-assembled monolayer and multilayer formation using redox-active Ru complex with phosphonic acids on silicon oxide surface

    NASA Astrophysics Data System (ADS)

    Ishida, Takao; Terada, Kei-ichi; Hasegawa, Kiichi; Kuwahata, Hironao; Kusama, Kazunori; Sato, Ryo; Nakano, Miki; Naitoh, Yasuhisa; Haga, Masa-aki

    2009-08-01

    The formation of self-assembled monolayer and multilayer using redox-active Ru complex molecules with phosphonic acids on SiO 2 surface has been examined using X-ray photoelectron spectroscopy (XPS), ellipsometry, and time of flight secondary mass-ion spectroscopy (TOF-SIMS). We found that an introduction of a Zr adlayer leads to higher surface molecular density of Ru complex SAMs on the SiO 2 surface, compared to that of obtained from the direct adsorption of Ru complex monolayer on the SiO 2 surface. We further tried to fabricate a multilayer film using this molecule with Zr(IV) ion acting as a chemical glue by a successive immersion process. The XPS data revealed that the molecular densities of the multilayers were also higher for the immobilization with Zr adlayer between Ru complex and SiO 2 surface than those without the Zr adlayer, suggesting that Zr adlayer is effective in forming highly packed molecular layer of phosphonic acids on SiO 2 surface. We found the film growth reached a saturation point after 6 layers on the SiO 2 surface. The film growth saturation can be explained by a molecular domain boundary effect encountered due to the large tilt angle of the molecular layer.

  13. Metastatic Bone Pain Palliation using 177Lu-Ethylenediaminetetramethylene Phosphonic Acid

    PubMed Central

    Alavi, Mehrosadat; Omidvari, Shapour; Mehdizadeh, Alireza; Jalilian, Amir R.; Bahrami-Samani, Ali

    2015-01-01

    177Lu-ethylenediaminetetramethylene phosphonic acid (EDTMP) is presently suggested as an excellent bone seeking radionuclide for developing metastatic bone pain (MBP) palliation agent owing to its suitable nuclear decay characteristics. To find the exact dosage and its efficiency, this clinical study was performed on the human being, using 177Lu-EDTMP for MBP palliation. 177Lu-EDTMP was prepared by Iran, atomic energy organization. Thirty consecutive patients with determined tumors, incontrollable MBP, and positive bone scan at 4 weeks before the beginning of the study participated in this study in the nuclear medicine ward. 177Lu-EDTMP in the form of sterile slow IV injection was administered with a dose of 29.6 MBq/kg. Short form of brief pain inventory questionnaire was used to evaluate the efficiency of the intervention. Questionnaires were filled out by an expert nuclear physician every 2 weeks while the cell blood count was also checked every 2 weeks up to 12 weeks for evaluation of bone marrow suppression and hematological toxicity. Furthermore, whole body scan was done at days 1, 3, and 7. Twenty-five patients showed a significant pain relief since 2 weeks after the injection, and continued until the end of the follow up period (12 weeks). There were no significant early complications such as bone marrow suppression, hematological toxicity, and no systemic adverse effects. No complication was observed in renal function. Twenty one patients showed flare phenomenon that was started after the 12.2 ± 1.78 h lasting for 38.4 ± 23.08. Sixteen patients (53%) were completely treated; nine patients (30%) showed a partial response, and five patients (17%) had no response to treatment. Total response to treatment was achieved in 25 patients (83%). At the end of the evaluation, no bone marrow suppression or hematologic toxicity was observed. 177Lu-EDTMP has shown suitable physical and biological properties with good results in long term bone pain relief for patients

  14. Corrosion resistant performances of alkanoic and phosphonic acids derived self-assembled monolayers on magnesium alloy AZ31 by vapor-phase method.

    PubMed

    Ishizaki, Takahiro; Okido, Masazumi; Masuda, Yoshitake; Saito, Naobumi; Sakamoto, Michiru

    2011-05-17

    Alkanoic and phosphonic acid derived self-assembled monolayers (SAMs) were formed on magnesium alloy by the vapor phase method. AFM and XPS studies showed that SAMs were formed on Mg alloy. The chemical and anticorrosive properties of the SAMs prepared on magnesium alloys were characterized using contact angle measurements, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. Water contact angle measurements revealed that, although SA and ISA have the same headgroup to anchor to the magnesium alloy surface, the packing density on the magnesium alloy surface could be considerably different. The contact angle hysteresis of SAMs with a carboxylate headgroup is much larger than that of SAMs with a phosphonic acid group. The XPS O 1s peaks indicated more likely a mix of mono-, bi-, or tridentate binding of phosphonic acid SAM to the oxide or hydroxide surface of the Mg alloy. The electrochemical measurements showed that the phosphonic acid derived SAM had better corrosion resistance compared to alkanoic acid derived SAM. The chemical stability of SAMs modified magnesium alloy was investigated using water contact angle and XPS measurements. The water contact angle and XPS measurements revealed that the molecular density of OP and PFEP on magnesium alloy would be higher than those of SA and ISA on magnesium alloy. PMID:21504153

  15. Synthesis of novel castor oil phosphonates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Castor oil has served as a versatile hydroxy fatty acid (HFA); its principle component, ricinoleic acid, can be isolated from castor oil and has been modified extensively for a number of applications. Additionally, phosphonates and their corresponding phosphonic acids are a functional moiety that ha...

  16. A phosphonic acid appended naphthalene diimide motif for self-assembly into tunable nanostructures through molecular recognition with arginine in water.

    PubMed

    Nandre, Kamalakar P; Bhosale, Sheshanath V; Rama Krishna, K V S; Gupta, Akhil; Bhosale, Sidhanath V

    2013-06-18

    A naphthalene diimide motif bearing phosphonic acid functionalities has been found to be self-assembled with L- and D-arginine through chirality induced molecular recognitions and leads to the formation of micrometre long nanobelts and spherical aggregates at pH 9 in water, respectively. PMID:23589823

  17. Novel sulfonated poly (ether ether ketone)/phosphonic acid-functionalized titania nanohybrid membrane by an in situ method for direct methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Wu, Hong; Cao, Ying; Li, Zhen; He, Guangwei; Jiang, Zhongyi

    2015-01-01

    Sulfonated poly (ether ether ketone)/phosphonic acid-functionalized titania nanohybrid membranes are prepared by an in situ method using titanium tetrachloride (TiCl4) as inorganic precursor and amino trimethylene phosphonic acid (ATMP) as modifier. Phosphonic acid-functionalized titania nanoparticles with a uniform particle size of ∼50 nm are formed and dispersed homogeneously in the SPEEK matrix with good interfacial compatibility. Accordingly, the nanohybrid membranes display remarkably enhanced proton conduction property due to the incorporation of additional sites for proton transport and the formation of well-connected channels by bridging the hydrophilic domains in SPEEK matrix. The nanohybrid membrane with 6 wt. % of phosphonic acid-functionalized titania nanoparticles exhibits the highest proton conductivity of 0.334 S cm-1 at 65 °C and 100% RH, which is 63.7% higher than that of pristine SPEEK membrane. Furthermore, the as-prepared nanohybrid membranes also show elevated thermal and mechanical stabilities as well as decreased methanol permeability.

  18. Enantiopure phosphonic acids as chiral inducers: homochiral crystallization of cobalt coordination polymers showing field-induced slow magnetization relaxation.

    PubMed

    Feng, Jian-Shen; Ren, Min; Cai, Zhong-Sheng; Fan, Kun; Bao, Song-Song; Zheng, Li-Min

    2016-05-25

    This Communication reports, for the first time, that enantiopure phosphonic acids can serve as chirality-inducing agents towards homochiral coordination polymers. Hence homochiral chain compounds (M)- or (P)-Co(SO4)(1,3-bbix)(H2O)3 (1M or 1P) are obtained successfully using an achiral precursor of 1,3-bis((1H-benzo[d]imidazol-1-yl)methyl)benzene (1,3-bbix) in the presence of a catalytic amount of (S)- or (R)-3-phenyl-2-((phosphonomethyl)amino)propanoic acid [(S)- or (R)-2-ppapH3]. Furthermore, compound 1M provides the first example of homochiral cobalt compounds showing field-induced single ion magnet behavior. PMID:27108929

  19. Liquid-liquid extraction separation of iron (III) with 2-ethyl hexyl phosphonic acid mono 2-ethyl hexyl ester.

    PubMed

    Jayachandran, J; Dhadke, P M

    1997-07-01

    Liquid-liquid extraction separation of iron(III) with 2-ethyl hexyl phosphonic acid mono 2-ethyl hexyl ester (PC-88A) in toluene has been studied. Quantitative extraction of iron(III) with 5 x 10(-3) M PC-88A in toluene is observed in the pH range 0.75-2.5. From the extracted complex species in the organic phase iron(III) was stripped with 1-4 M HNO(3), 1.5-4 M H(2)SO(4) and 1.5-4 M HCl, and later determined spectrophotometrically by thiocyanate method. Separation of iron(III) was carried out with some of the first transition metals in binary and multicomponent mixtures. This method was extended for the determination of iron in real samples. PMID:18966864

  20. Alpha-heteroatom derivatized analogues of 3-(acetylhydroxyamino)propyl phosphonic acid (FR900098) as antimalarials.

    PubMed

    Verbrugghen, Thomas; Vandurm, Pierre; Pouyez, Jenny; Maes, Louis; Wouters, Johan; Van Calenbergh, Serge

    2013-01-10

    To explore the hitherto successful derivatization of the α-carbon of fosmidomycin, a series of new α-substituted analogues was prepared. This was done by introduction of a heteroatom (N or O) in α-position to the phosphonate and using the resultant OH and NH₂ groups as a handle for appending a variety of substituents by means of several functional groups such as ether, amide, urea, and 1,4-triazole. The synthesized molecules, as a racemic mixture, were assayed for their EcDXR inhibitory potency. Both the α-azido-analogue and the α-hydroxylated analogue proved most promising, and docking experiments were performed. Although several compounds showed high potency when assayed against Plasmodium falciparum K1 in human erythrocytes, a clear correlation between the enzyme inhibition constants and P. falciparum inhibition concentrations could not be found. PMID:23215035

  1. Improve the Strength of PLA/HA Composite Through the Use of Surface Initiated Polymerization and Phosphonic Acid Coupling Agent

    PubMed Central

    Wang, Tongxin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Ting, Andy Hai; Dong, Quanxiao; Yang, Mingshu; Mitchell, James W.

    2011-01-01

    Bioresorbable composite made from degradable polymers, e.g., polylactide (PLA), and bioactive calcium phosphates, e.g., hydroxyapatite (HA), are clinically desirable for bone fixation, repair and tissue engineering because they do not need to be removed by surgery after the bone heals. However, preparation of PLA/HA composite from non-modified HA usually results in mechanical strength reductions due to a weak interface between PLA and HA. In this study, a calcium-phosphate/phosphonate hybrid shell was developed to introduce a greater amount of reactive hydroxyl groups onto the HA particles. Then, PLA was successfully grafted on HA by surface-initiated polymerization through the non-ionic surface hydroxyl groups. Thermogravimetric analysis indiated that the amount of grafted PLA on HA can be up to 7 %, which is about 50 % greater than that from the literature. PLA grafted HA shows significantly different pH dependent ζ-potential and particle size profiles from those of uncoated HA. By combining the phosphonic acid coupling agent and surface initiated polymerization, PLA could directly link to HA through covalent bond so that the interfacial interaction in the PLA/HA composite can be significantly improved. The diametral tensile strength of PLA/HA composite prepared from PLA-grafted HA was found to be over twice that of the composite prepared from the non-modified HA. Moreover, the tensile strength of the improved composite was 23 % higher than that of PLA alone. By varying additional variables, this approach has the potential to produce bioresorbable composites with improved mechanical properties that are in the range of natural bones, and can have wide applications for bone fixation and repair in load-bearing areas. PMID:22399838

  2. Analysis of Phosphonic Acids: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS999

    SciTech Connect

    Owens, J; Vu, A; Koester, C

    2008-10-31

    The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method titled Analysis of Diisopropyl Methylphosphonate, Ethyl Hydrogen Dimethylamidophosphate, Isopropyl Methylphosphonic Acid, Methylphosphonic Acid, and Pinacolyl Methylphosphonic Acid in Water by Multiple Reaction Monitoring Liquid Chromatography/Tandem Mass Spectrometry: EPA Version MS999. This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to validate and verify the analytical procedures described in EPA Method MS999 for analysis of the listed phosphonic acids and surrogates in aqueous samples. The gathered data from this validation study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of EPA Method MS999 can be determined.

  3. A sialic acid-derived phosphonate analog inhibits different strains of influenza virus neuraminidase with different efficiencies.

    PubMed

    White, C L; Janakiraman, M N; Laver, W G; Philippon, C; Vasella, A; Air, G M; Luo, M

    1995-02-01

    A phosphonate analog of N-acetyl neuraminic acid (PANA) has been designed as a potential neuraminidase (NA) inhibitor and synthesized as both the alpha (ePANA) and beta (aPANA) anomers. Inhibition of type A (N2) and type B NA activity by ePANA was approximately a 100-fold better than by sialic acid, but inhibition of type A (N9) NA was only ten-fold better than by sialic acid. The aPANA compound was not a strong inhibitor for any of the NA strains tested. The crystal structures at 2.4 A resolution of ePANA complexed to type A (N2) NA, type A (N9) NA and type B NA and aPANA complexed to type A (N2) NA showed that neither of the PANA compounds distorted the NA active site upon binding. No significant differences in the NA-ePANA complex structures were found to explain the anomalous inhibition of N9 neuraminidase by ePANA. We put forward the hypothesis that an increase in the ePANA inhibition compared to that caused by sialic acid is due to (1) a stronger electrostatic interaction between the inhibitor phosphonyl group and the active site arginine pocket and (2) a lower distortion energy requirement for binding of ePANA. PMID:7844831

  4. Bioavailability and bioconcentration potential of perfluoroalkyl-phosphinic and -phosphonic acids in zebrafish (Danio rerio): Comparison to perfluorocarboxylates and perfluorosulfonates.

    PubMed

    Chen, Fangfang; Gong, Zhiyuan; Kelly, Barry C

    2016-10-15

    Currently, information regarding bioavailability and bioconcentration potential of perfluoroalkyl phosphinic acids (PFPiAs) in aquatic organisms does not exist. The main objective of the present study was to assess uptake and elimination kinetics of PFPiAs in zebrafish (Danio rerio) following aqueous exposure. The results showed that PFPiA exposure can result in very high steady-state bioconentration factors (BCFss), compared to perfluorocarboxylates and perfluorosulfonates.C6/C10 PFPiA exhibited the highest BCFss, ranging between 10(7) and 10(10), orders of magnitude higher than those for long-chain perfluorocarboxylates. Strong positive relationships were observed between BCFss versus the membrane-water distribution coefficient (Dmw) and the protein-water partition coefficient (Kpw) of the studied perfluoroalkyl substances. However, BCFss exhibited a substantial drop for the very hydrophobic PFPiAs (C8/C10 and C6/C12 PFPiAs). The reduced BCFss of these long-chain PFPiAs (perfluoroalkyl chain length=18; Dmw=10(9)) is likely the result of reduced bioavailability due to interaction with solute molecules/organic matter present in the water phase and/or reduced gill membrane permeability. While PFPiAs can be metabolized to perfluoroalkyl phosphonic acids, the metabolic transformation rate seems insufficient to counteract the high degree of uptake across gill membranes. These findings help to better understand exposure pathways and bioaccumulation behavior of these important perfluorinated acids in aquatic systems. PMID:27285794

  5. Characterization of an Indole-3-Acetamide Hydrolase from Alcaligenes faecalis subsp. parafaecalis and Its Application in Efficient Preparation of Both Enantiomers of Chiral Building Block 2,3-Dihydro-1,4-Benzodioxin-2-Carboxylic Acid.

    PubMed

    Mishra, Pradeep; Kaur, Suneet; Sharma, Amar Nath; Jolly, Ravinder S

    2016-01-01

    Both the enantiomers of 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid are valuable chiral synthons for enantiospecific synthesis of therapeutic agents such as (S)-doxazosin mesylate, WB 4101, MKC 242, 2,3-dihydro-2-hydroxymethyl-1,4-benzodioxin, and N-[2,4-oxo-1,3-thiazolidin-3-yl]-2,3-dihydro-1,4-benzodioxin-2-carboxamide. Pharmaceutical applications require these enantiomers in optically pure form. However, currently available methods suffer from one drawback or other, such as low efficiency, uncommon and not so easily accessible chiral resolving agent and less than optimal enantiomeric purity. Our interest in finding a biocatalyst for efficient production of enantiomerically pure 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid lead us to discover an amidase activity from Alcaligenes faecalis subsp. parafaecalis, which was able to kinetically resolve 2,3-dihydro-1,4-benzodioxin-2-carboxyamide with E value of >200. Thus, at about 50% conversion, (R)-2,3-dihydro-1,4-benzodioxin-2-carboxylic acid was produced in >99% e.e. The remaining amide had (S)-configuration and 99% e.e. The amide and acid were easily separated by aqueous (alkaline)-organic two phase extraction method. The same amidase was able to catalyse, albeit at much lower rate the hydrolysis of (S)-amide to (S)-acid without loss of e.e. The amidase activity was identified as indole-3-acetamide hydrolase (IaaH). IaaH is known to catalyse conversion of indole-3-acetamide (IAM) to indole-3-acetic acid (IAA), which is phytohormone of auxin class and is widespread among plants and bacteria that inhabit plant rhizosphere. IaaH exhibited high activity for 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which was about 65% compared to its natural substrate, indole-3-acetamide. The natural substrate for IaaH indole-3-acetamide shared, at least in part a similar bicyclic structure with 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which may account for high activity of enzyme towards this un-natural substrate. To the best of

  6. Characterization of an Indole-3-Acetamide Hydrolase from Alcaligenes faecalis subsp. parafaecalis and Its Application in Efficient Preparation of Both Enantiomers of Chiral Building Block 2,3-Dihydro-1,4-Benzodioxin-2-Carboxylic Acid

    PubMed Central

    Mishra, Pradeep; Kaur, Suneet; Sharma, Amar Nath; Jolly, Ravinder S.

    2016-01-01

    Both the enantiomers of 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid are valuable chiral synthons for enantiospecific synthesis of therapeutic agents such as (S)-doxazosin mesylate, WB 4101, MKC 242, 2,3-dihydro-2-hydroxymethyl-1,4-benzodioxin, and N-[2,4-oxo-1,3-thiazolidin-3-yl]-2,3-dihydro-1,4-benzodioxin-2-carboxamide. Pharmaceutical applications require these enantiomers in optically pure form. However, currently available methods suffer from one drawback or other, such as low efficiency, uncommon and not so easily accessible chiral resolving agent and less than optimal enantiomeric purity. Our interest in finding a biocatalyst for efficient production of enantiomerically pure 2,3-dihydro-1,4-benzodioxin-2-carboxylic acid lead us to discover an amidase activity from Alcaligenes faecalis subsp. parafaecalis, which was able to kinetically resolve 2,3-dihydro-1,4-benzodioxin-2-carboxyamide with E value of >200. Thus, at about 50% conversion, (R)-2,3-dihydro-1,4-benzodioxin-2-carboxylic acid was produced in >99% e.e. The remaining amide had (S)-configuration and 99% e.e. The amide and acid were easily separated by aqueous (alkaline)-organic two phase extraction method. The same amidase was able to catalyse, albeit at much lower rate the hydrolysis of (S)-amide to (S)-acid without loss of e.e. The amidase activity was identified as indole-3-acetamide hydrolase (IaaH). IaaH is known to catalyse conversion of indole-3-acetamide (IAM) to indole-3-acetic acid (IAA), which is phytohormone of auxin class and is widespread among plants and bacteria that inhabit plant rhizosphere. IaaH exhibited high activity for 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which was about 65% compared to its natural substrate, indole-3-acetamide. The natural substrate for IaaH indole-3-acetamide shared, at least in part a similar bicyclic structure with 2,3-dihydro-1,4-benzodioxin-2-carboxamide, which may account for high activity of enzyme towards this un-natural substrate. To the best of

  7. Surface modification of alumina-coated silica nanoparticles in aqueous sols with phosphonic acids and impact on nanoparticle interactions.

    PubMed

    Pauly, Céline Schmitt; Genix, Anne-Caroline; Alauzun, Johan G; Sztucki, Michael; Oberdisse, Julian; Hubert Mutin, P

    2015-07-15

    It is often necessary to tailor nanoparticle (NP) interactions and their compatibility with a polymer matrix by grafting organic groups, but the commonly used silanization route offers little versatility, particularly in water. Herein, alumina-coated silica NPs in aqueous sols have been modified for the first time with low molecular-weight phosphonic acids (PAs) bearing organic groups of various hydrophobicities and charges: propyl, pentyl and octyl PAs, and two PAs bearing hydrophilic groups, either a neutral diethylene glycol (DEPA) or a potentially charged carboxylic acid (CAPA) group. The interactions and aggregation in the sols have been investigated using zeta potential measurements, dynamic light scattering, transmission electron microscopy, and small-angle scattering methods. The surface modification has been studied using FTIR and (31)P MAS NMR spectroscopies. Both high grafting density ρ and high hydrophobicity of the groups on the PAs induced aggregation, whereas suspensions of NPs grafted by DEPA remained stable up to the highest ρ. Unexpectedly, CAPA-modified NPs showed aggregation even at low ρ, suggesting that the carboxylic end group was also grafted to the surface. Surface modification of aqueous sols with PAs allows thus for the grafting of a higher density and a wider variety of organic groups than organosilanes, offering an increased control of the interactions between NPs, which is of interest for designing waterborne nanocomposites. PMID:26134150

  8. Pigment Changes Associated with Application of Ethephon ((2-Chloroethyl)phosphonic Acid) to Fig (Ficus carica L.) Fruits

    PubMed Central

    Puech, Antoine A.; Rebeiz, Constantin A.; Crane, Julian C.

    1976-01-01

    The application of (2-chloroethyl)phosphonic acid (Ethephon) to `Mission' fig fruits (Ficus carica L.) during late period II of their development stimulated ripening and change in color from green to bluish black within 8 days. Chlorophylls a and b decreased rapidly within 4 days after Ethephon treatment, and degradation continued at a decreasing rate for an additional 4 days, at which time the fruits had attained their maximum diameter and were considered fully ripe. Levels of β-carotene, lutein, violaxanthin, and neoxanthin decreased in a pattern similar to that of chlorophylls a and b. The rates of β-carotene and lutein degradation were initially greater than those of the xanthophyll pigments. Degradation rates of the various carotenoids were comparable 4 to 8 days after treatment. There was no measurable anthocyanin synthesis during a 2- to 4-day period following Ethephon treatment. Beyond this lag phase, anthocyanin accumulation was linear, and the amount of pigment synthesized was a function of both light intensity and duration. Although Ethephon promoted the rate of anthocyanin accumulation, it did not increase the total amount of pigment synthesized in treated fruits. Etiolation of fruits from the time of Ethephon treatment until maturity stimulated an increase in growth and completely inhibited anthocyanin production in the skin. Ethephon-treated fruits which ripened while etiolated were larger in diameter and higher in both fresh and dry weights than nonetiolated controls. Images PMID:16659515

  9. Evaluation of a 7-Methoxycoumarin-3-carboxylic Acid Ester Derivative as a Fluorescent, Cell-Cleavable, Phosphonate Protecting Group.

    PubMed

    Wiemer, Andrew J; Shippy, Rebekah R; Kilcollins, Ashley M; Li, Jin; Hsiao, Chia-Hung Christine; Barney, Rocky J; Geng, M Lei; Wiemer, David F

    2016-01-01

    Cell-cleavable protecting groups often enhance cellular delivery of species that are charged at physiological pH. Although several phosphonate protecting groups have achieved clinical success, it remains difficult to use these prodrugs in live cells to clarify biological mechanisms. Here, we present a strategy that uses a 7-methoxycoumarin-3-carboxylic acid ester as a fluorescent protecting group. This strategy was applied to synthesis of an (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) analogue to assess cellular uptake and human Vγ9Vδ2 T cell activation. The fluorescent ester displayed low cellular toxicity (IC50 >100 μm) and strong T cell activation (EC50 =0.018 μm) relative to the unprotected anion (EC50 =23 μm). The coumarin-derived analogue allowed no-wash analysis of biological deprotection, which revealed rapid internalization of the prodrug. These results demonstrate that fluorescent groups can be applied both as functional drug delivery tools and useful biological probes of drug uptake. PMID:26503489

  10. Pigment Changes Associated with Application of Ethephon ((2-Chloroethyl)phosphonic Acid) to Fig (Ficus carica L.) Fruits.

    PubMed

    Puech, A A; Rebeiz, C A; Crane, J C

    1976-04-01

    The application of (2-chloroethyl)phosphonic acid (Ethephon) to ;Mission' fig fruits (Ficus carica L.) during late period II of their development stimulated ripening and change in color from green to bluish black within 8 days. Chlorophylls a and b decreased rapidly within 4 days after Ethephon treatment, and degradation continued at a decreasing rate for an additional 4 days, at which time the fruits had attained their maximum diameter and were considered fully ripe. Levels of beta-carotene, lutein, violaxanthin, and neoxanthin decreased in a pattern similar to that of chlorophylls a and b. The rates of beta-carotene and lutein degradation were initially greater than those of the xanthophyll pigments. Degradation rates of the various carotenoids were comparable 4 to 8 days after treatment.There was no measurable anthocyanin synthesis during a 2- to 4-day period following Ethephon treatment. Beyond this lag phase, anthocyanin accumulation was linear, and the amount of pigment synthesized was a function of both light intensity and duration. Although Ethephon promoted the rate of anthocyanin accumulation, it did not increase the total amount of pigment synthesized in treated fruits. Etiolation of fruits from the time of Ethephon treatment until maturity stimulated an increase in growth and completely inhibited anthocyanin production in the skin. Ethephon-treated fruits which ripened while etiolated were larger in diameter and higher in both fresh and dry weights than nonetiolated controls. PMID:16659515

  11. Inclusion of 1-naphthylacetic acid and 2-(1-naphthyl)acetamide into three typical multiresidue methods for LC/MS/MS analysis of tomatoes and zucchini.

    PubMed

    Lozano, Ana; Pérez-Parada, Andrés; Heinzen, Horacio; Fernández-Alba, Amadeo R

    2012-01-01

    In spite of high plant growth regulator application rates, little has been reported in the literature on determination of their residues in fruits and vegetables. This would be useful in monitoring good manufacturing practices and overall safety through the enforcement of maximum residue levels (MRLs). The present work describes method validation for the determination of 1-naphthylacetic acid (NAA) and 2(1-naphthyl)acetamide (NAAm) in tomato and zucchini using the mini-Luke, ethyl acetate (EtOAc) and acetate-buffered quick, easy, cheap, effective, rugged, and safe (QuEChERS) methods. Samples were spiked at two different levels: 50 and 100 pg/kg for NAA and 20 and 100 pg/kg for NAAm. These compounds were analyzed within the same chromatographic run with LC coupled to triple quadrupole MS (LC/(QqQ)MS/MS) in positive and negative electrospray ionization [ESI(+) and ESI(-)] modes for NAAm and NAA, respectively. For analyte confirmation, LC/ESI(-)QTOF-MS was also investigated given that NAA has only one multiple reaction monitoring transition (185.1-*140.9 m/z). These three common methods were used to determine linearity, recoveries, precision (RSD), matrix effects, repeatability, and reproducibility (n = 5) for the selected matrixes. In terms of the Directorate-General for Health and Consumers (DG-SANCO) guidelines, only insignificant differences were found for the multiresidue methods tested, regardless of the commodity. Matrix-matched calibration was used, and LODs were below 10.1 pg/kg for NAA and 6.0 pg/kg for NAAm, which were lower than the MRLs established in current European Union legislation for these compounds. Obtained recoveries for NAA ranged from 87 to 107% with RSD values below 10% for mini-Luke, 83 to 107% with RSD <11% for EtOAc, and 76 to 85% with RSD <7% for QuEChERS. NAAm recoveries ranged from 74 to 102% with RSD 5 15% for mini-Luke, 76 to 97% with RSD <4% for EtOAc, and 76 to 93% with RSD < 5% for QuEChERS. The linearity of the response over two

  12. Fourier transform infrared spectroscopic study on microemulsion systems of alkali metal salts of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester

    NASA Astrophysics Data System (ADS)

    Zhou, Weijin; Shi, Nai; Xu, Zhen-hua; Wu, JinGuang

    1994-01-01

    There has recently been a growing interest in the reverse micelle and microemulsion formation in the solvent extraction process. In our previous papers, the formation of W/O type microemulsions in the organic phase of sodium or potassium salt of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester was investigated by using the subtraction technique on FTIR. In this paper, the conductance and the FTIR spectroscopic study on the microemulsion systems of Li, Na, and K salts of this acidic extractant was reported.

  13. Improvement of catalytic activity of Candida rugosa lipase in the presence of calix[4]arene bearing iminodicarboxylic/phosphonic acid complexes modified iron oxide nanoparticles.

    PubMed

    Ozyilmaz, Elif; Bayrakci, Mevlut; Yilmaz, Mustafa

    2016-04-01

    In the present study, iron oxide magnetite nanoparticles, prepared through a co-precipitation method, were coated with phosphonic acid or iminodicarboxylic acid derivatives of calix[4]arene to modulate their surfaces with different acidic groups. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through sol-gel encapsulation. The catalytic activities and enantioselectivities of the two encapsulated lipases in the hydrolysis reaction of (R/S)-naproxen methyl ester and (R/S)-2-phenoxypropionic acid methyl ester were assessed. The results showed that the activity and enantioselectivity of the lipase were improved when the lipase was encapsulated in the presence of calixarene-based additives; the encapsulated lipase with the phosphonic acid derivative of calix[4]arene had an excellent rate of enantioselectivity against the (R/S)-naproxen methyl and (R/S)-2-phenoxypropionic acid methyl esters, with E=350 and 246, respectively, compared to the free enzyme. The encapsulated lipases (Fe-Calix-N(COOH)) and (Fe-Calix-P) showed good loading ability and little loss of enzyme activity, and the stability of the catalyst was very good; they only lost 6-11% of the enzyme's activity after five batches. PMID:26698535

  14. Discovery of the antibiotic phosacetamycin via a new mass spectrometry-based method for phosphonic acid detection

    PubMed Central

    Evans, Bradley S.; Zhao, Changming; Gao, Jiangtao; Evans, Courtney M.; Ju, Kou-San; Doroghazi, James R.; van der Donk, Wilfred A.; Kelleher, Neil L.; Metcalf, William W.

    2013-01-01

    Naturally occurring phosphonates such as phosphinothricin (Glufosinate, a commercially used herbicide) and fosfomycin (Monurol, a clinically used antibiotic) have proved to be potent and useful biocides. Yet this class of natural products is still an under explored family of secondary metabolites. Discovery of the biosynthetic pathways responsible for the production of these compounds has been simplified by using gene based screening approaches, but detection and identification of the natural products the genes produce has been hampered by a lack of high-throughput methods for screening potential producers under various culture conditions. Here we present an efficient mass-spectrometric method for the selective detection of natural products containing phosphonate and phosphinate functional groups. We have used this method to identify a new phosphonate metabolite, phosacetamycin, whose structure, biological activity, and biosynthetic gene cluster are reported. PMID:23474169

  15. Epoxy Phosphonate Crosslinkers for Providing Flame Resistance to Cotton Textiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two new monomers (2-methyl-oxiranylmethyl)-phosphonic acid dimethyl ester (3) and [2-(dimethoxy-phosphorylmethyl)-oxyranylmethyl]-phosphonic acid dimethyl ester (6) were prepared and used with dicyandiamide (7) and citric acid (8) to impart flame resistance to cotton plain weave, twill, and 80:20-co...

  16. Positional isomerism makes a difference: phosphonic acid anchoring ligands with thienyl spacers in copper(i)-based dye-sensitized solar cells.

    PubMed

    Klein, Y Maximilian; Willgert, Markus; Prescimone, Alessandro; Constable, Edwin C; Housecroft, Catherine E

    2016-03-21

    With the aim of improving the photoconversion efficiencies of heteroleptic [Cu(Lanchor)(Lancillary)](+) dyes in n-type dye-sensitized solar cells (DSCs), the previously favoured anchor ((6,6'-dimethyl-[2,2'-bipyridine]-4,4'-diyl)bis(4,1-phenylene))bis(phosphonic acid) (1) has been replaced by analogues 2 and 3 containing 2-thienyl spacers between the 2,2'-bipyridine metal-binding domain and the phosphonic acid anchoring groups. The synthesis and characterization of 2 and 3 (2-thienyl spacer with phosphonic acid in the 5- and 4-positions, respectively) are reported. A stepwise, on-surface method was used to assemble [Cu(Lanchor)(Lancillary)](+) dyes onto FTO/TiO2 electrodes with Lanchor = 1, 2 or 3, and Lancillary = 6,6'-bis(trifluoromethyl)-2,2'-bipyridine (4), 6-trifluoromethyl-2,2'-bipyridine (5), 6,6'-dimethyl-2,2'-bipyridine (6), and 6-methyl-2,2'-bipyridine (7). Changing the solvent in the dye-bath from CH2Cl2 to acetone had only a small effect on the photoconversion efficiencies of [Cu(1)(4)](+), [Cu(1)(5)](+) and [Cu(1)(6)](+); the optimal dye in this series was [Cu(1)(5)](+). Comparable DSC performances were achieved by using either anchor 1 or 2, but there is improved electron injection if the phosphonic acid group is in the 4- rather than 5-position of the thienyl ring (i.e. anchor 3 is superior to 2). Similar open-circuit voltages (VOC) are achieved on going from 1 to 3 with a given Lancillary; although there is typically a gain in short-circuit current denisty (JSC) on going from 1 or 3 to 2, there is an ≈50-60 mV drop in VOC on introducing 2 as the anchor. The best photoconversion efficiencies are obtained for the dye [Cu(3)(5)](+) (η = 2.40% relative to an N719 reference of 5.76%). The conclusions reached from plots of current-density (J) against potential (V), and external quantum efficiency spectra are supported by electrochemical impedance spectroscopic measurements. PMID:26856366

  17. Lubrication of Individual Microcontacts by a Self-Assembled Alkyl Phosphonic Acid Monolayer on α-Al2O3(0001).

    PubMed

    Paul, Jonas; Meltzer, Christian; Braunschweig, Björn; Peukert, Wolfgang

    2016-08-23

    We report on the tribological behavior of a self-assembled alkyl phosphonic acid monolayer on the microscale using the colloidal probe technique. Friction-load data and adhesion forces were measured with borosilicate glass particles on uncoated and octadecylphosphonic acid (ODPA) coated α-Al2O3(0001) surfaces. A significant decrease in friction force was observed after surface coating, while the adhesion force was only moderately reduced. We assume the lubrication effect of the ODPA self-assembled monolayer (SAM) to be close to the maximum obtainable of alkyl phosphonic acids in the studied system due to the high molecular order which was confirmed by vibrational sum-frequency generation. At small loads, a nonlinear dependence of friction force to load was maintained after surface coating. However, a shift from a contact behavior well described by the DMT model toward the JKR model occurred that is possibly related to the altered elastic properties of the coated surface. With increasing load, a linear friction-load behavior was observed on the coated samples. Molecular plowing and adhesive interactions were identified as responsible mechanisms. In all friction experiments, we could not detect any wear neither of the colloidal probes nor at the surfaces of uncoated and coated samples. This proves the high wear resistivity of the studied ODPA SAM. PMID:27478898

  18. The Rates of Hydrolysis of Thymidyl-3', 5'-Thymidine-H-Phosphonate: The Possible Role of Nucleic Acids Linked by Diesters of Phosphorous Acid in the Origins of Life

    NASA Astrophysics Data System (ADS)

    Peyser, John R.; Ferris, James P.

    2001-08-01

    Thymidyl-3',5'-thymidine H-phosphonate undergoes acid, base, and water-catalyzed hydrolysis. The products were 3'-thymidine H-phosphonate, 5'-thymidine H-phosphonate, and thymidine in a ratio of 1:1:2. The rate constants are 1.8 × 10^-3 M^-1 sec^-1, 7.2 × 10^3 M^-1 sec^-1, and 1.5 × 10^-6 sec^-1 for acid, base and water catalysis, respectively. These values are comparable with previous reports for the rates of hydrolysis of simple dialkyl esters of phosphorous acids. The Arrhenius activation energy for the base-catalyzed reaction is 20 kcal/mol. and the enthalpy and entropy of activation are 19 kcal/mol and -14 eu., respectively. The Gibbs free energy of activation is 23 kcal/mol. The rate constants suggest that nucleic acids linked by diesters of phosphorous acid hydrolyze too rapidly in aqueous solution to have accumulated in useful amounts on the primitive Earth.

  19. The Chemical and Physical Properties of Poly(ε-caprolactone) Scaffolds Functionalised with Poly(vinyl phosphonic acid-co-acrylic acid).

    PubMed

    Bassi, A K; Gough, J E; Zakikhani, M; Downes, S

    2011-01-01

    There is a clinical need for a synthetic alternative to bone graft substitute (BGS) derived from demineralised bone matrix. We report the electrospinning of Poly(ε-caprolactone) (PCL) to form a 3-dimensional scaffold for use as a synthetic BGS. Additionally, we have used Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA) to improve bone formation. Fibres were formed using a 10% w/v PCL/acetone solution. Infrared spectroscopy confirmed that the electrospinning process had no effect on the functional groups present in the resulting structure. The electrospun scaffolds were coated with PVPA (PCL/PVPA), and characterised. The stability of the PVPA coating after immersion in culture medium was assessed over 21 days. There was rapid release of the coating until day 2, after which the coating became stable. The wettability of the PCL scaffolds improved significantly, from 123.3 ± 10.8° to 43.3 ± 1.2° after functionalisation with PVPA. The compressive strength of the PCL/PVPA scaffolds (72 MPa) was significantly higher to that of the PCL scaffold (14 MPa), and an intermediate between trabecular and cortical bone (7 MPa and 170 MPa, resp.). The study has demonstrated that the PCL/PVPA scaffold has the desired chemical and biomechanical characteristics required for a material designed to be used as a BGS. PMID:22073379

  20. The Chemical and Physical Properties of Poly(ε-caprolactone) Scaffolds Functionalised with Poly(vinyl phosphonic acid-co-acrylic acid)

    PubMed Central

    Bassi, A. K.; Gough, J. E.; Zakikhani, M.; Downes, S.

    2011-01-01

    There is a clinical need for a synthetic alternative to bone graft substitute (BGS) derived from demineralised bone matrix. We report the electrospinning of Poly(ε-caprolactone) (PCL) to form a 3-dimensional scaffold for use as a synthetic BGS. Additionally, we have used Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA) to improve bone formation. Fibres were formed using a 10% w/v PCL/acetone solution. Infrared spectroscopy confirmed that the electrospinning process had no effect on the functional groups present in the resulting structure. The electrospun scaffolds were coated with PVPA (PCL/PVPA), and characterised. The stability of the PVPA coating after immersion in culture medium was assessed over 21 days. There was rapid release of the coating until day 2, after which the coating became stable. The wettability of the PCL scaffolds improved significantly, from 123.3 ± 10.8° to 43.3 ± 1.2° after functionalisation with PVPA. The compressive strength of the PCL/PVPA scaffolds (72 MPa) was significantly higher to that of the PCL scaffold (14 MPa), and an intermediate between trabecular and cortical bone (7 MPa and 170 MPa, resp.). The study has demonstrated that the PCL/PVPA scaffold has the desired chemical and biomechanical characteristics required for a material designed to be used as a BGS. PMID:22073379

  1. Fate of malathion and a phosphonic acid in activated sludge with varying solids retention times.

    PubMed

    Janeczko, Allen K; Walters, Edward B; Schuldt, Steven J; Magnuson, Matthew L; Willison, Stuart A; Brown, Lisa M; Ruiz, Oscar N; Felker, Daniel L; Racz, LeeAnn

    2014-06-15

    This study examined the ability of activated sludge (AS) to sorb and biodegrade ethylmethylphosphonic acid (EMPA) and malathion, a degradation product and surrogate, respectively, for an organophosphate chemical warfare agent. Sorption equilibrium isotherm experiments indicate that sorption of EMPA and malathion to AS is negligible. EMPA at a concentration of 1 mg L(-1) degraded by approximately 30% with apparent first-order kinetics, possibly via co-metabolism from nitrification. Heterotrophic bacteria and abiotic mechanisms, however, are largely responsible for malathion degradation also with apparent first-order kinetics. EMPA did not inhibit chemical oxygen demand (COD) oxidation or nitrification activity, although malathion did appear to induce a stress response resulting in inhibition of COD oxidation. The study also included a 30-day experiment in which malathion, at a concentration of 5 mg L(-1), was repeatedly fed to AS in bench-scale sequencing batch reactors (SBRs) operating at different solids retention times (SRTs). Peak malathion concentrations occurred at day 4.5, with the longer SRTs yielding greater peak malathion concentrations. The AS reduced the malathion concentrations to nearly zero by day 10 for all SRTs, even when the malathion concentration in the influent increased to 20.8 mg L(-1). The data suggest a biodegradation pathway for malathion involving an oxygenase. Phylogenetic analyses revealed that all samples had an abundance of Zoogloea, though there was greater bacterial diversity in the SBR with the SRT of 50 days. The SBR with an SRT of 9.5 days had an apparent reduction in the diversity of the bacterial community. PMID:24709533

  2. Effective methylation of phosphonic acids related to chemical warfare agents mediated by trimethyloxonium tetrafluoroborate for their qualitative detection and identification by gas chromatography-mass spectrometry.

    PubMed

    Valdez, Carlos A; Leif, Roald N; Alcaraz, Armando

    2016-08-24

    The effective methylation of phosphonic acids related to chemical warfare agents (CWAs) employing trimethyloxonium tetrafluoroborate (TMO·BF4) for their qualitative detection and identification by gas chromatography-mass spectrometry (GC-MS) is presented. The methylation occurs in rapid fashion (1 h) and can be conveniently carried out at ambient temperature, thus providing a safer alternative to the universally employed diazomethane-based methylation protocols. Optimization of the methylation parameters led us to conclude that methylene chloride was the ideal solvent to carry out the derivatization, and that even though methylated products can be observed surfacing after only 1 h, additional time was not found to be detrimental but beneficial to the process particularly when dealing with analytes at low concentrations (∼10 μg mL(-1)). Due to its insolubility in methylene chloride, TMO·BF4 conveniently settles to the bottom during the reaction and does not produce additional interfering by-products that may further complicate the GC-MS analysis. The method was demonstrated to successfully methylate a variety of Schedule 2 phosphonic acids, including their half esters, resulting in derivatives that were readily detected and identified using the instrument's spectral library. Most importantly, the method was shown to simultaneously methylate a mixture of the organophosphorus-based nerve agent hydrolysis products: pinacolyl methylphosphonate (PMPA), cyclohexyl methylphosphonate (CyMPA) and ethyl methylphosphonate (EMPA) (at a 10 μg mL(-1) concentration each) in a fatty acid ester-rich organic matrix (OPCW-PT-O3) featured in the 38th Organisation for the Prohibition of Chemical Weapons (OPCW) Proficiency Test. In addition, the protocol was found to effectively methylate N,N-diethylamino ethanesulfonic acid and N,N-diisopropylamino ethanesulfonic acid that are products arising from the oxidative degradation of the V-series agents VR and VX respectively. The

  3. Decontamination of aqueous glyphosate, (aminomethyl)phosphonic acid, and glufosinate solutions by electro-fenton-like process with Mn2+ as the catalyst.

    PubMed

    Balci, Beytul; Oturan, Mehmet A; Oturan, Nihal; Sirés, Ignasi

    2009-06-10

    The ability of the modified electro-Fenton-like (EF-like) process to degrade aqueous solutions of glyphosate, which is the most widely used herbicide in the world, has been assessed with Mn(2+) and other metal ions as catalysts to overcome the problems posed by some stable metal ion complexes of phosphonate herbicides. Bulk electrolyses with a carbon-felt cathode and Pt anode were performed in an undivided cell under galvanostatic conditions to study the effect of the applied current as well as Mn(2+) and glyphosate concentrations. The herbicide was completely destroyed in all cases following a pseudofirst-order kinetics, and the second-order rate constant for its reaction with (*)OH was determined. The decay trends obtained by high-performance liquid chromatography-fluorometric detection (HPLC-FL) and ion chromatography analysis were similar. AMPA [(aminomethyl)phosphonic acid] was the major reaction intermediate and showed slower pseudofirst-order destruction kinetics. The high mineralization degree obtained for glyphosate solutions confirmed the great performance of the EF-like process with Mn(2+), which promotes the C-N cleavage by (*)OH attack as the first oxidation step and the C-P cleavage in a further step. High-level decontamination achieved for AMPA and glufosinate solutions corroborated the benefits of this oxidation process. PMID:19438208

  4. Phosphonate ester hydrolysis catalyzed by two lanthanum ions. Intramolecular nucleophilic attack of coordinated hydroxide and lewis acid activation

    SciTech Connect

    Tsubouchi, A.; Bruice, T.C.

    1995-07-19

    (8-Hydroxy-2-quinolyl)methyl (8-hydroxy-2-quinolyl)methyl phosphonate (I) has been synthesized as a model compound and investigated in terms of catalysis of hydrolysis by two metal ions in concert. Removal of one of two 8-hydroxyquinoline ligands of I to provide (8-hydroxy-2-quinolyl)methylmethylphosphonate (II) leads to the formation of the 1:1 complex (II)La, which is hydrolytically inert but subject to catalysis by free La{sup 3+}. From thermodynamic studies of metal ion complexation and comparison of the kinetics of hydrolysis of I and II in the presence of metal ions, we conclude the following. The phosphonate ester I forms a hydrolytically active 1:2 complex (I)La{sub 2} with La{sup 3+} but inert 1:1 complexes with Zn{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Cu{sup 2+}, and Al{sup 3+}. The La{sup 3+} in the (I)La{sub 2} complex serve to (i) facilitate the formation of metal ligated hydroxide as an intramolecule nucleophile; (ii) stabilize the transition state of the hydrolysis by neutralization of the phosphonate negative charge; and (iii) interact with an incipient oxyanion of the leaving alcohol. The two La{sup 3+} functions operate in concert and provide nearly 10{sup 13} rate enhancement. Consequently the 1:2 complex (I)La{sub 2}(OH{sub 2}){sub n-1}(OH) may serve as a model for the 3`-5` exonuclease reaction of E. coli DNA polymerase I. 39 refs., 7 figs., 3 tabs.

  5. Proton transport pathways in an acid-base complex consisting of a phosphonic acid group and a 1,2,3-triazolyl group.

    PubMed

    Yue, Baohua; Yan, Liuming; Han, Shuaiyuan; Xie, Liqing

    2013-07-01

    The proton transport pathways in an acid-base complex consisting of a phosphonic acid group and a 1,2,3-triazolyl group were studied using density functional theory (DFT) calculations in terms of stable configurations and transition states of the molecular or ionic dimers and trimers and verified by proof-of-concept experiments including experimental measurements of overall conductivity and (1)H NMR and FTIR spectroscopy of the methylphosphonic acid (MPA) and 1,2,3-triazole (Tri) complex as well as overall proton conductivity of polymeric blend of poly(vinylphosphonic acid) (PVPA) and poly(4-vinyl-1H-1,2,3-triazole) (PVTri). From the DFT calculations of dimers and trimers composed of ethylphosphonic acid (EPA), Tri, and their deprotonated counterparts, it was concluded that the intermolecular hydrogen bonds of the transition states corresponding to proton transport are much shorter than those of stable configurations, but the O-H and N-H bonds are much longer than those of stable configurations. The tautomerization activation energy decreases from 0.927-1.176 eV in Tri-Tri dimers to 0.336-0.444 eV in the EPA-Tri dimers. From the proof-of-concept experiments, about a 50 fold increase in overall conductivity was observed in the MPA-Tri complex consisting of 10% (molar ratio) MPA compared to pure Tri, and the calculated activation energy is consistent with the experimental activation energy evaluated from temperature dependence of proton conductivity of pure Tri and the MPA-Tri complex. In addition, the fast proton exchange between MPA and Tri, consistent with the DFT calculations, was verified by (1)H NMR and FTIR spectroscopy. Finally, a polymeric blend of PVPA and PVTri was prepared, and its proton conductivity at about 2.1 mS·cm(-1) in anhydrous state at 100 °C was observed to be significantly higher than that of PVPA or of poly(VPA-co-1-vinyl-1,2,4-triazole). The proton conductivity of the polymeric PVPA and PVTri blend in humidity state is in the same range as

  6. Extraction kinetics of rare earth metals with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester using a hollow fiber membrane extractor

    SciTech Connect

    Kubota, Fukiko; Goto, Masahiro; Nakashio, Fumiyuki; Hano, Tadashi

    1995-03-01

    A kinetic study concerning chemical complexation-based solvent extraction of rare earth metals with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester dissolved as an extractant in n-heptane was carried out using a microporous hydrophobic hollow fiber membrane extractor. The effects of concentration of chemical species in aqueous and organic feed solutions on the apparent permeabilities of metal species for extraction and stripping, respectively, were investigated to clarify the permeation mechanism. From the experimental results it was predicted that the permeation rate is controlled by diffusion of the chemical species in aqueous and organic phases and by interfacial chemical reaction. The experimental data were analyzed by the diffusion model accompanied with an interfacial reaction, taking into account the velocity distributions of the aqueous and organic phases through the inner and outer sides of the hollow fiber.

  7. Fluorophosphonate-functionalised titanium via a pre-adsorbed alkane phosphonic acid: a novel dual action surface finish for bone regenerative applications.

    PubMed

    Ayre, Wayne Nishio; Scott, Tom; Hallam, Keith; Blom, Ashley W; Denyer, Stephen; Bone, Heather K; Mansell, Jason P

    2016-02-01

    Enhancing vitamin D-induced human osteoblast (hOB) maturation at bone biomaterial surfaces is likely to improve prosthesis integration with resultant reductions in the need for revision arthroplasty consequent to aseptic loosening. Biomaterials that are less appealing to microorganisms implicated in implant failures through infection are also highly desirable. However, finding surfaces that enhance hOB maturation to active vitamin D yet deter bacteria remain elusive. In addressing this, we have sought to bio-functionalise titanium (Ti) with lysophosphatidic acid (LPA) and related, phosphatase-resistant, LPA analogues. The impetus for this follows our discovery that LPA co-operates with active vitamin D3 metabolites to secure hOB maturation in vitro including cells grown upon Ti. LPA has also been found, by others, to inhibit virulence factor production and biofilm formation of the human opportunistic pathogen Pseudomonas aeruginosa. Collectively, selected LPA species might offer potential dual-action surface finishes for contemporary bone biomaterials. In attaching a phosphatase-resistant LPA analogue to Ti we took advantage of the affinity of alkane phosphonic acids for TiO2. Herein, we provide evidence for the facile development of a dual-action Ti surface for potential orthopaedic and dental applications. Successful conjugation of an LPA analogue (3S)1-fluoro-3-hydroxy-4-(oleoyloxy)butyl-1-phosphonate (FHBP) to the Ti surface was supported through physiochemical characterisation using x-ray photoelectron spectroscopy and secondary ion mass spectrometry. hOB maturation to active vitamin D3 was enhanced for cells grown on FHBP-Ti whilst these same surfaces exhibited clear antiadherent properties towards a clinical isolate of Staphylococcus aureus. PMID:26704553

  8. Peramivir Phosphonate Derivatives as Influenza Neuraminidase Inhibitors.

    PubMed

    Wang, Peng-Cheng; Fang, Jim-Min; Tsai, Keng-Chang; Wang, Shi-Yun; Huang, Wen-I; Tseng, Yin-Chen; Cheng, Yih-Shyun E; Cheng, Ting-Jen Rachel; Wong, Chi-Huey

    2016-06-01

    Peramivir is a potent neuraminidase (NA) inhibitor for treatment of influenza infection by intravenous administration. By replacing the carboxylate group in peramivir with a phosphonate group, phosphono-peramivir (6a), the dehydration and deoxy derivatives (7a and 8a) as well as their corresponding monoalkyl esters are prepared from a pivotal intermediate epoxide 12. Among these phosphonate compounds, the dehydration derivative 7a that has a relatively rigid cyclopentene core structure exhibits the strongest inhibitory activity (IC50 = 0.3-4.1 nM) against several NAs of wild-type human and avian influenza viruses (H1N1, H3N2, H5N1, and H7N9), although the phosphonate congener 6a is unexpectedly less active than peramivir. The inferior binding affinity of 6a is attributable to the deviated orientations of its phosphonic acid and 3-pentyl groups in the NA active site as inferred from the NMR, X-ray diffraction, and molecular modeling analyses. Compound 7a is active to the oseltamivir-resistant H275Y strains of H1N1 and H5N1 viruses (IC50 = 73-86 nM). The phosphonate monoalkyl esters (6b, 6c, 7b, 7c, 8b, and 8c) are better anti-influenza agents (EC50 = 19-89 nM) than their corresponding phosphonic acids (EC50 = 50-343 nM) in protection of cells from the viral infection. The phosphonate monoalkyl esters are stable in buffer solutions (pH 2.0-7.4) and rabbit serum; furthermore, the alkyl group is possibly tuned to attain the desired pharmacokinetic properties. PMID:27167096

  9. New phosphonate reagents for aldehyde homologation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New phosphonate reagents were developed for the two-carbon homologation of aldehydes to unbranched- or methyl-branched unsaturated aldehydes. The phosphonate reagents, diethyl methylformyl-2-phosphonate dimethylhydrazone and diethyl ethylformyl-2-phosphonate dimethylhydrazone, contained a protected...

  10. DEGRADATION OF NITRILOTRIS (METHYLENEPHOSPHONIC ACID) AND RELATED (AMINO) PHOSPHONATE CHELATING AGENTS IN THE PRESENCE OF MANGANESE AND MOLECULAR OXYGEN. (R826376)

    EPA Science Inventory

    Phosphonates are used in an increasing variety of industrial and household
    applications including cooling waters systems, oil production, textile industry,
    and detergents. Phosphonates are not biodegraded during wastewater treatment but
    instead are removed by adsor...

  11. Multifunctional p-phosphonated calixarenes.

    PubMed

    Martin, Adam D; Raston, Colin L

    2011-09-21

    p-Phosphonic acid calix[n]arenes and their O-alkylated lower rim analogues are remarkably versatile macrocycles, with applications in selective diameter uptake of single walled carbon nano-tubes, as surfactants in stabilising and protecting nano-particles and graphene sheets, as crystal growth modifiers for inorganic systems, in encapsulating molecules of anti-cancer carboplatin, self assembly into nano-arrays, including nano-fibres and molecular capsules, and for binding metal ions including biologically relevant Ca(2+). They are readily accessible via five or six high yielding steps from the parent p-Bu(t) substituted compounds. PMID:21629880

  12. Poly(arlyene ether sulfone) based semi-interpenetrating polymer network membranes containing cross-linked poly(vinyl phosphonic acid) chains for fuel cell applications at high temperature and low humidity conditions

    NASA Astrophysics Data System (ADS)

    Kim, Kihyun; Heo, Pilwon; Ko, Taeyun; Kim, Ki-hyun; Kim, Sung-Kon; Pak, Chanho; Lee, Jong-Chan

    2015-10-01

    Semi-interpenetrating polymer network (semi-IPN) membranes are prepared by in-situ casting and thermal-initiated radical polymerization of vinyl phosphonic acid (VPA) and bis(2-(methacryloyloxy)ethyl) phosphate (BMAEP) in N,N-dimethylacetamide solutions of sulfonated poly(arylene ether sulfone) (SPAES). The incorporation of VPA units into the SPAES membranes improves proton conductivity especially at high temperature and low humidity conditions. In addition the cross-linker, BMAEP, prevents the decrease of the mechanical and chemical stabilities by the aliphatic linear poly(vinyl phosphonic acid) chains in the semi-IPN membranes, and furthermore the phosphonic acid group in BMAEP can prevent the decrease of the proton conductivity by the formation of cross-linked structures. Therefore, the resulting semi-IPN membranes show high proton conductivities up to 15 mS cm-1 at 120 °C and 40% RH. The fuel cell performance (187 mW cm-2 at 120 °C and 40% RH) of membrane-electrode assembly (MEA) from the semi-IPN membrane is found to be superior to that (145 mW cm-2 at 120 °C and 40% RH) of MEA from the SPAES membrane. The durability test result at the operating conditions indicates that the semi-IPN membrane is electrochemically very stable maintaining the low hydrogen cross-over and high power densities.

  13. Complexation of trivalent cations (Al(III), Cr(III), Fe(III)) with two phosphonic acids in the pH range of fresh waters.

    PubMed

    Lacour, S; Deluchat, V; Bollinger, J C; Bernard Serpaud

    1998-08-01

    The complex formation constants of two phosphonic acids, HEDP and ATMP, with three trivalent metallic cations, Al(III), Cr(III) and Fe(III), have been determined by acid-base titration at 25 degrees C and constant ionic strength (0.1 mol l(-1), KNO(3)), using Martell and Motekaitis' computer programs. Species distribution curves showed that all three cations are in complex form in the pH range of fresh waters (5-9). The study of different cation/ligand ratios proved that both ligands mainly form anionic soluble complexes for systems having an excess of ligand-as protonated and unprotonated forms and especially ternary complexes with HEDP. For higher metal concentrations (excess of cation), weakly soluble species of HEDP and ATMP were formed with Al(III) and Cr(III). Two insoluble complexes with ATMP have been identified by SEM/EDAX as AlH(3)X((s)) and Cr(2)X((s)). Regarding Fe(III) species, Fe(OH)(3(s)) precipitate seems to predominate in solution. PMID:18967224

  14. Actinide phosphonate complexes in aqueous solutions

    SciTech Connect

    Nash, K.L.

    1993-10-01

    Complexes formed by actinides with carboxylic acids, polycarboxylic acids, and aminopolycarboxylic acids play a central role in both the basic and process chemistry of the actinides. Recent studies of f-element complexes with phosphonic acid ligands indicate that new ligands incorporating doubly ionizable phosphonate groups (-PO{sub 3}H{sub 2}) have many properties which are unique chemically, and promise more efficient separation processes for waste cleanup and environmental restoration. Simple diphosphonate ligands form much stronger complexes than isostructural carboxylates, often exhibiting higher solubility as well. In this manuscript recent studies of the thermodynamics and kinetics of f-element complexation by 1,1 and 1,2 diphosphonic acid ligands are described.

  15. Separation of carrier-free {sup 90}Y from high level waste by extraction chromatographic technique using 2-ethylhexyl-2-ethylhexyl phosphonic acid (KSM-17)

    SciTech Connect

    Achuthan, P.V.; Dhami, P.S.; Kannan, R.; Gopalakrishnan, V.; Ramanujam, A.

    2000-01-01

    An extraction chromatographic technique has been developed for the separation of carrier-free {sup 90}Y from the {sup 90}Sr present in the high level waste (HLW) of the Purex process. When a Purex HLW solution in 2--3 M HNO{sub 3} is passed through a CMPO-Chromosorb-102 (CAC) column, all the trivalent, tetravalent, and hexavalent ions are sorbed. The effluent from this experiment, after adjusting the pH to 2 with NaOH, was passed through a 2-ethylhexyl-2-ethylhexyl phosphonic acid (KSM-17)-Chromosorb-102 (KSMC) extraction chromatographic column where only {sup 90}Y was sorbed. All the other ions ({sup 90}Sr, {sup 137}Cs, {sup 125}Sb, {sup 106}Ru, {sup 106}Rh, etc.) were washed off with dilute HNO{sub 3} (pH 2), and carrier-free {sup 90}Y was eluted with 0.5 M HNO{sub 3}. This technique can yield {sup 90}Y in mCi levels in pure form for medical applications. The {sup 90}Sr can be used repeatedly after allowing for {sup 90}Y buildup.

  16. Grafting of Poly(methyl methacrylate) Brushes from Magnetite Nanoparticles Using a Phosphonic Acid Based Initiator by Ambient Temperature Atom Transfer Radical Polymerization (ATATRP)

    PubMed Central

    2008-01-01

    Poly(methyl methacrylate) in the brush form is grown from the surface of magnetite nanoparticles by ambient temperature atom transfer radical polymerization (ATATRP) using a phosphonic acid based initiator. The surface initiator was prepared by the reaction of ethylene glycol with 2-bromoisobutyrl bromide, followed by the reaction with phosphorus oxychloride and hydrolysis. This initiator is anchored to magnetite nanoparticles via physisorption. The ATATRP of methyl methacrylate was carried out in the presence of CuBr/PMDETA complex, without a sacrificial initiator, and the grafting density is found to be as high as 0.90 molecules/nm2. The organic–inorganic hybrid material thus prepared shows exceptional stability in organic solvents unlike unfunctionalized magnetite nanoparticles which tend to flocculate. The polymer brushes of various number average molecular weights were prepared and the molecular weight was determined using size exclusion chromatography, after degrafting the polymer from the magnetite core. Thermogravimetric analysis, X-ray photoelectron spectra and diffused reflection FT-IR were used to confirm the grafting reaction.

  17. Production of Indole-3-Acetic Acid via the Indole-3-Acetamide Pathway in the Plant-Beneficial Bacterium Pseudomonas chlororaphis O6 Is Inhibited by ZnO Nanoparticles but Enhanced by CuO Nanoparticles

    PubMed Central

    Zeng, Jia; McLean, Joan E.; Britt, David W.; Zhan, Jixun; Anderson, Anne J.

    2012-01-01

    The beneficial bacterium Pseudomonas chlororaphis O6 produces indole-3-acetic acid (IAA), a plant growth regulator. However, the pathway involved in IAA production in this bacterium has not been reported. In this paper we describe the involvement of the indole-3-acetamide (IAM) pathway in IAA production in P. chlororaphis O6 and the effects of CuO and ZnO nanoparticles (NPs). Sublethal levels of CuO and ZnO NPs differentially affected the levels of IAA secreted in medium containing tryptophan as the precursor. After 15 h of growth, CuO NP-exposed cells had metabolized more tryptophan than the control and ZnO NP-challenged cells. The CuO NP-treated cells produced higher IAA levels than control cultures lacking NPs. In contrast, ZnO NPs inhibited IAA production. Mixing of CuO and ZnO NPs resulted in an intermediate level of IAA production relative to the levels in the separate CuO and ZnO NP treatments. The effect of CuO NPs on IAA levels could be duplicated by ions at the concentrations released from the NPs. However, ion release did not account for the inhibition caused by the ZnO NPs. The mechanism underlying changes in IAA levels cannot be accounted for by effects on transcript accumulation from genes encoding a tryptophan permease or the IAM hydrolase in 15-h cultures. These findings raise the issue of whether sublethal doses of NPs would modify the beneficial effects of association between plants and bacteria. PMID:22210218

  18. Molecular determinants of thyroid hormone receptor selectivity in a series of phosphonic acid derivatives: 3D-QSAR analysis and molecular docking.

    PubMed

    Wang, Fang-Fang; Yang, Wei; Shi, Yong-Hui; Le, Guo-Wei

    2015-10-01

    A mathematical study was performed on a set of phosphonic acid derivatives that are substrates for thyroid hormone receptor β (TRβ) and thyroid hormone receptor α (TRα), three-dimensional quantitative structure-activity relationship (3D-QSAR) models using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods were employed to investigate the structural requirements for this series of compounds with improved activity. Some descriptors were also employed to significantly improve the performance of the derived models. The CoMFA model for TRβ exhibited Rcv(2) of 0.612, Rpred(2) of 0.7218, whereas CoMSIA model showed Rcv(2) of 0.621, R(2)pred of 0.7358; the CoMFA model for TRα displayed Rcv(2) of 0.678, Rpred(2) of 0.6424, and the CoMSIA model had Rcv(2) of 0.671, Rpred(2) of 0.6932, which indicate that the constructed models are statistically significant. The derived contour maps further pointed out the regions where interactive fields may influence the activity. In order to validate the QSAR models and explore the origin of the selectivity at the amino acid level, molecular docking was developed, and the results indicate that Arg282, Arg320, Asn331, Gly332, Thr329 and His435 for TRβ, but Ala225, Arg228, Met259, Arg262 and His381 for TRα, respectively are important residues. The information obtained from the QSAR models can be used in the design of more potent TR agonists. PMID:26363198

  19. Comparative assessment of the environmental hazards of and exposure to perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs): Current knowledge, gaps, challenges and research needs.

    PubMed

    Wang, Zhanyun; Cousins, Ian T; Berger, Urs; Hungerbühler, Konrad; Scheringer, Martin

    2016-01-01

    Perfluoroalkyl phosphonic and phosphinic acids (PFPAs and PFPiAs) are sub-groups of per- and polyfluoroalkyl substances (PFASs) that have been commercialized since the 1970s, particularly as defoamers in pesticide formulations and wetting agents in consumer products. Recently, C4/C4 PFPiA and its derivatives have been presented as alternatives to long-chain PFASs in certain applications. In this study, we systematically assess the publicly available information on the hazardous properties, occurrence, and exposure routes of PFPAs and PFPiAs, and make comparisons to the corresponding properties of their better-known carboxylic and sulfonic acid analogs (i.e. PFCAs and PFSAs). This comparative assessment indicates that [i] PFPAs likely have high persistence and long-range transport potential; [ii] PFPiAs may transform to PFPAs (and possibly PFCAs) in the environment and biota; [iii] certain PFPAs and PFPiAs can only be slowly eliminated from rainbow trout and rats, similarly to long-chain PFCAs and PFSAs; [iv] PFPAs and PFPiAs have modes-of-action that are both similar to, and different from, those of PFCAs and PFSAs; and [v] the measured levels of PFPAs/PFPiAs in the global environment and biota appear to be low in comparison to PFCAs and PFSAs, suggesting, for the time being, low risks from PFPAs and PFPiAs alone. Although risks from individual PFPAs/PFPiAs are currently low, their ongoing production and use and high persistence will lead to increasing exposure and risks over time. Furthermore, simultaneous exposure to PFPAs, PFPiAs and other PFASs may result in additive effects necessitating cumulative risk assessments. To facilitate effective future research, we highlight possible strategies to overcome sampling and analytical challenges. PMID:26922149

  20. Production, biodistribution, and dosimetry of 47Sc-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid as a bone-seeking radiopharmaceutical

    PubMed Central

    Fathi, Fatemeh; Moghaddam-Banaem, Leila; Shamsaei, Mojtaba; Samani, Ali; Maragheh, Mohammad G.

    2015-01-01

    In this study 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (DOTMP) was used as the polyaminophosphonic acid carrier ligand and the therapeutic potential of the bone seeking radiopharmaceutical 47Sc-DOTMP was assessed by measuring its dosage–dependent skeletal uptake and then the absorbed radiation dose of human organs was estimated. Because of limited availability of 47Sc we performed some preliminary studies using 46Sc. 46Sc was produced with a specific activity of 116.58 MBq/mg (3.15 mCi/mg) and radionuclide purity of 98%. 46Sc-DOTMP was prepared and an activity of 1.258 MBq (34 μCi) at a chelant-to-metal ratio of 60:1 was administered to five groups of mice with each group containing 3 mice that were euthanized at 4, 24, 48, 96 and 192 h post administration. The heart, lungs, liver, spleen, kidneys, intestine, skin, muscle, and a femur were excised, weighed, and counted. The data were analyzed to determine skeletal uptake and source organ residence times and cumulated activities for 47Sc-DOTMP. 46Sc-DOTMP complex was prepared in radiochemical purity about 93%. In vitro stability of complex was evaluated at room temperature for 48 h. Biodistribution studies of complex in mice were studied for 7 days. The data were analyzed to estimate skeletal uptake and absorbed radiation dose of human organs using biodistribution data from mice. By considering the results, 47Sc-DOTMP is a possible therapeutic agent for using in palliation of bone pain due to metastatic skeletal lesions from several types of primary cancers in prostate, breast, etc. PMID:26500402

  1. Mn2+ complexes of 1-oxa-4,7-diazacyclononane based ligands with acetic, phosphonic and phosphinic acid pendant arms: stability and relaxation studies.

    PubMed

    Drahoš, Bohuslav; Pniok, Miroslav; Havlíčková, Jana; Kotek, Jan; Císařová, Ivana; Hermann, Petr; Lukeš, Ivan; Tóth, Eva

    2011-10-21

    A new class of macrocyclic ligands based on 1-oxa-4,7-diazacyclononane was synthesized and their Mn(2+) complexes were investigated with respect to stability and relaxation properties. Each ligand has two pendant arms involving carboxylic (H(2)L(1)--1-oxa-4,7-diazacyclononane-4,7-diacetic acid), phosphonic (H(4)L(2)--1-oxa-4,7-diazacyclononane-4,7-bis(methylenephosphonic acid)), phosphinic (H(2)L(3)--1-oxa-4,7-diazacyclononane-4,7-bis(methylenephosphinic acid)) or phenylphosphinic (H(2)L(4)--1-oxa-4,7-diazacyclononane-4,7-bis[methylene(phenyl)phosphinic acid]) acid moieties. H(2)L(3) and H(2)L(4) were synthesized for the first time. The crystal structure of the Mn(2+) complex with H(2)L(4) confirmed a coordination number of 6 for Mn(2+). The protonation constants of all ligands and the stability constants of their complexes with Mn(2+) and some biologically or biomedically relevant metal ions were determined by potentiometry. The protonation sequence of H(2)L(3) was followed by (1)H and (31)P NMR titration and the second protonation step was attributed to the second macrocyclic nitrogen atom. The potentiometric data revealed a relatively low thermodynamic stability of the Mn(2+) complexes with all ligands investigated. For H(2)L(3) and H(2)L(4), full Mn(2+) complexation cannot be achieved even with 100% ligand excess. The transmetallation of MnL(1) and MnL(2) with Zn(2+) was too fast to be followed at pH 6. Variable temperature (1)H NMRD and (17)O NMR measurements have been performed on MnL(1) and MnL(2) to provide information on water exchange and rotational dynamics. The (17)O chemical shifts indicate hydration equilibrium between mono- and bishydrated species for MnL(1), while MnL(2) is monohydrated. The water exchange is considerably faster on MnL(1) (k(ex)(298) = 1.2 × 10(9) s(-1)) than on MnL(2) (k(ex)(298) = 1.2 × 10(7) s(-1)). Small endogenous anions (phosphate, carbonate, citrate) do not replace the coordinated water in either of the complexes, but they

  2. Synthesis of Methylenecyclopropane Analogues of Antiviral Nucleoside Phosphonates

    PubMed Central

    Yan, Zhaohua; Zhou, Shaoman; Kern, Earl R.; Zemlicka, Jiri

    2006-01-01

    Synthesis of methylenecyclopropane analogues of nucleoside phosphonates 6a, 6b, 7a and 7b is described. Cyclopropyl phosphonate 8 was transformed in four steps to methylenecyclopropane phosphonate 16. The latter intermediate was converted in seven steps to the key Z- and E-methylenecyclopropane alcohols 23 and 24 separated by chromatography. Selenoxide eliminations (15 → 16 and 22 → 23 + 24) were instrumental in the synthesis. The Z- and E-isomers 23 and 24 were transformed to bromides 25a and 25b which were used for alkylation of adenine and 2-amino-6-chloropurine to give intermediates 26a, 26b, 26c and 26d. Acid hydrolysis provided the adenine and guanine analogues 6a, 6b, 7a and 7b. Phosphonates 6b and 7b are potent inhibitors of replication of Epstein-Barr virus (EBV). PMID:16758001

  3. Modulation of the inhibitory effect of phenylethylamine on spontaneous motor activity in mice by CPP-(+/-)-3-(2-carboxypiperazin-4-YL)-propyl-1-phosphonic acid.

    PubMed

    Lapin, I P; Yuwiler, A

    1997-02-01

    Beta-phenyl-ethylamine (PEA) at dose of 50 mg/kg inhibits spontaneous, motor activity in mice. CPP- (+/-)-3-(2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid, a selective and competitive antagonist of N-methyl-D-aspartate (NMDA) receptors, in doses of 0.2-10 mg/kg dose-dependently antagonizes this inhibitory effect of PEA. This effect of CPP appeared to be selective because the inhibitory action of PEA was not altered by pretreament with noncompetitive antagonists of NMDA receptors, such as dizocilpine (MK-801), phencyclidine (PCP), 1-phenylcyclohexylamine (PCA) or by antagonists of other behavioral effects of PEA such as haloperidol, baclofen and phenibut (beta-phenyl-GABA). CPP failed to antagonize the inhibitory effect of other tested drugs such as diazepam, haloperidol, baclofen and phenibut. Intracerebroventricularly administered NMDA (0.2 microM), an agonist of NMDA receptors, suppressed the antagonistic effects of CPP against PEA. This suggests that anti-PEA effect of CPP is related to NMDA receptors. Anti-PEA effect of CPP is not due to accelerated deamination of PEA in CPP-treated mice. When small doses of PEA (5 and 10 mg/kg) and CPP (0.2 and 1 mg/kg) were used, the synergism of two drugs was observed. CPP (1 mg/kg) and deprenyl (0.5 mg/kg) an inhibitor monoamine oxidase of B type (MAO-B), had additive effects on PEA-induced inhibition of locomotion. This effect was not associated with any further inhibition of activity of brain MAO-B (over the inhibition induced by deprenyl alone-by 65%) under high (80 microM) or low (4.3 microM) concentration of PEA as a substrate in the medium. Mechanism of the interaction of CPP and PEA, two drugs belonging to different groups of biologically active compounds, deserves further studies. PMID:9050075

  4. The Modification of Indium Tin Oxide with Phosphonic Acids: Mechanism of Binding, Tuning of Surface Properties, and Potential for Use in Organic Electronic Applications

    SciTech Connect

    Hotchkiss, Peter J.; Jones, Simon C.; Paniagua, Sergio A.; Sharma, Asha; Kippelen, Bernard; Armstrong, Neal R.; Marder, Seth R.

    2012-03-20

    Transparent metal oxides, in particular, indium tin oxide (ITO), are critical transparent contact materials for applications in next-generation organic electronics, including organic light emitting diodes (OLEDs) and organic photovoltaics (OPVs). Understanding and controlling the surface properties of ITO allows for the molecular engineering of the ITO–organic interface, resulting in fine control of the interfacial chemistries and electronics. In particular, both surface energy matching and work function compatibility at material interfaces can result in marked improvement in OLED and OPV performance. Although there are numerous ways to change the surface properties of ITO, one of the more successful surface modifications is the use of monolayers based on organic molecules with widely variable end functional groups. Phosphonic acids (PAs) are known to bind strongly to metal oxides and form robust monolayers on many different metal oxide materials. They also demonstrate several advantages over other functionalizing moieties such as silanes or carboxylic acids. Most notably, PAs can be stored in ambient conditions without degradation, and the surface modification procedures are typically robust and easy to employ. This Account focuses on our research studying PA binding to ITO, the tunable properties of the resulting surfaces, and subsequent effects on the performance of organic electronic devices. We have used surface characterization techniques such as X-ray photoelectron spectroscopy (XPS) and infrared reflection adsorption spectroscopy (IRRAS) to determine that PAs bind to ITO in a predominantly bidentate fashion (where two of three oxygen atoms from the PA are involved in surface binding). Modification of the functional R-groups on PAs allows us to control and tune the surface energy and work function of the ITO surface. In one study using fluorinated benzyl PAs, we can keep the surface energy of ITO relatively low and constant but tune the surface work

  5. A New Epoxy Bis-Phosphonate Crosslinker for Durable Fire Retardancy on Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new epoxy bis-phosphonate crosslinker for cotton [2-(dimethoxy-phosphorylmethyl)-oxiranylmethyl]-phosphonic acid dimethyl ester was prepared in two steps from 3-chloro-2-chloromethylpropene in 55% yield. The new monomer was characterized by proton and carbon NMR and GC-mass spectrometry. This cro...

  6. Novel self-assembled phosphonic acids monolayers applied in N-channel perylene diimide (PDI) organic field effect transistors

    NASA Astrophysics Data System (ADS)

    Cheng, Heng; Huai, Jinyue; Cao, Li; Li, Zhefeng

    2016-08-01

    Phosphoric acid (PA) self-assembled monolayers (SAMs) have been developed for applications in organic field-effect transistors (OFETs). This efficient interface modification is helpful for semiconductor layer to form crystal thin film during vapor deposition. Results show that the PDI-i8C based OFETs with PA SAMs exhibit field-effect mobilities up to 0.014 cm2 V-1 s-1 (with ODPA as SAMs), which is over 500 times higher than the device without SAMs. Also, transistors with Naph6PA as SAMs show up to 1.5 × 10-3 cm2 V-1 s-1. By studying the morphology of semiconductor layer and SAMs surface, it is found that ODPA bilayer structure plays a key role in inducing PDI-i8C to form orderly crystal thin film.

  7. Studies on the Labeling of Ethylenediaminetetramethylene Phosphonic Acid, Methylene Diphosphonate, Sodium Pyrophosphate and Hydroxyapatite with Lutetium-177 for use in Nuclear Medicine.

    PubMed

    Abbasi, Imtiaz Ahmed

    2015-01-01

    For the treatment of skeletal metastasis, a therapeutic radionuclide tagged with a bone seeking ligand is required, while for radiation synovectomy (RS), a therapeutic radionuclide irreversibly attached to pre-formed particles of appropriate size is required. Radio lanthanides are mostly therapeutic, and ligands containing phosphate groups are predominantly bone seekers. Exploiting these facts, number of new therapeutic radiopharmaceuticals could be developed. Labeling of four phosphate containing materials was pursued in the present study. It was hypothesized that various (177)Lu-labeled bone-seeking complexes such as (177)Lu-ethylenediaminetetramethylene phosphonic acid (EDTMP), (177)Lu-methylene diphosphonate (MDP) and (177)Lu-pyrophosphate (PYP) could be developed as agents for palliative radiotherapy of bone pain due to skeletal metastases, and (177)Lu-Hydroxyapatite (HA) could be developed as an agent for radiosynovectomy of small joints. Lyophilized kit vials of EDTMP, MDP and sodium pyrophosphate (Na-PYP) were formulated. HA particles were synthesized locally and purity was checked by high-performance liquid chromatography (HPLC). (177)Lu was labeled with EDTMP, MDP, PYP, and HA and the behavior of all was studied by radio-thin layer chromatography (TLC) radio-HPLC and radio-electrophoresis. Radio-TLC confirmed the labeling. HPLC analysis too verified the labeling. Radio-electrophoresis results depicted peaks for (177)Lu-MDP, (177)Lu-EDTMP and (177)Lu-PYP at 3.37 ± 0.06 cm, 5.53 ± 0.15 cm and 7.03 ± 0.06 cm respectively confirming negative charge on each specie as all migrated toward positive anode. All 3 methods verified the labeling. The study demonstrated that EDTMP, MDP and PYP form stable complexes with (177)Lu in injectable solution form. HA particulates could too be labeled with (177)Lu with high radiochemical yields (>98%) in suspension form. Former three could be utilized as bone-pain palliation agents for the treatment of bone metastases, and

  8. Studies on the Labeling of Ethylenediaminetetramethylene Phosphonic Acid, Methylene Diphosphonate, Sodium Pyrophosphate and Hydroxyapatite with Lutetium-177 for use in Nuclear Medicine

    PubMed Central

    Abbasi, Imtiaz Ahmed

    2015-01-01

    For the treatment of skeletal metastasis, a therapeutic radionuclide tagged with a bone seeking ligand is required, while for radiation synovectomy (RS), a therapeutic radionuclide irreversibly attached to pre-formed particles of appropriate size is required. Radio lanthanides are mostly therapeutic, and ligands containing phosphate groups are predominantly bone seekers. Exploiting these facts, number of new therapeutic radiopharmaceuticals could be developed. Labeling of four phosphate containing materials was pursued in the present study. It was hypothesized that various 177Lu-labeled bone-seeking complexes such as 177Lu-ethylenediaminetetramethylene phosphonic acid (EDTMP), 177Lu-methylene diphosphonate (MDP) and 177Lu-pyrophosphate (PYP) could be developed as agents for palliative radiotherapy of bone pain due to skeletal metastases, and 177Lu-Hydroxyapatite (HA) could be developed as an agent for radiosynovectomy of small joints. Lyophilized kit vials of EDTMP, MDP and sodium pyrophosphate (Na-PYP) were formulated. HA particles were synthesized locally and purity was checked by high-performance liquid chromatography (HPLC). 177Lu was labeled with EDTMP, MDP, PYP, and HA and the behavior of all was studied by radio-thin layer chromatography (TLC) radio-HPLC and radio-electrophoresis. Radio-TLC confirmed the labeling. HPLC analysis too verified the labeling. Radio-electrophoresis results depicted peaks for 177Lu-MDP, 177Lu-EDTMP and 177Lu-PYP at 3.37 ± 0.06 cm, 5.53 ± 0.15 cm and 7.03 ± 0.06 cm respectively confirming negative charge on each specie as all migrated toward positive anode. All 3 methods verified the labeling. The study demonstrated that EDTMP, MDP and PYP form stable complexes with 177Lu in injectable solution form. HA particulates could too be labeled with 177Lu with high radiochemical yields (>98%) in suspension form. Former three could be utilized as bone-pain palliation agents for the treatment of bone metastases, and the later could be

  9. Homochiral metal phosphonate nanotubes.

    PubMed

    Liu, Xun-Gao; Bao, Song-Song; Huang, Jian; Otsubo, Kazuya; Feng, Jian-Shen; Ren, Min; Hu, Feng-Chun; Sun, Zhihu; Zheng, Li-Min; Wei, Shiqiang; Kitagawa, Hiroshi

    2015-10-21

    A new type of homochiral metal-organic nanotubular structures based on metal phosphonates are reported, namely, (R)- or (S)-[M(pemp)(H2O)2][M = Co(II) (1), Ni(II) (2)] [pemp(2-) = (R)- or (S)-(1-phenylethylamino)methylphosphonate]. In these compounds, the tube-walls are purely inorganic, composed of metal ions and O-P-O bridges. The cavity of the nanotube is hydrophilic with one coordination water pointing towards the center, while the outer periphery of the nanotube is hydrophobic, decorated by the phenylethyl groups of pemp(2-). The thermal stabilities, adsorption and proton conductivity properties are investigated. PMID:26324662

  10. Synthesis, characterization and computational studies of three α-amino-phosphonic acids derivatives from Meta, Ortho and Para aminophenol

    NASA Astrophysics Data System (ADS)

    Hellal, A.; Chafaa, S.; Chafai, N.

    2016-01-01

    In this paper, we report first, the synthesis of three α-aminophosphonic acids from Meta-aminophenol, Ortho-aminophenol and Para-aminophenol. Then, we present a detailed DFT study based on B3LYP/6-31G (d, p) of geometrical structures and electronic properties of these compounds. The vibrational frequencies determined experimentally were compared with DFT gradient calculations which were obtained theoretically employing the B3LYP/6-31G (d, p) basis set method for the optimized geometry of the compound. The vibrations obtained from DFT method were found in good agreement with the experimental data. The study was extended to the HOMO-LUMO analysis to calculate the energy gap (Δ), Ionization potential (I), Electron Affinity (A), Global Hardness (η), Chemical Potential (μ) and Global Electrophilicity (ω). The calculated HOMO and LUMO energy reveals shows that the charge transfers occurring within the molecule. On the basis of vibrational analyses, the thermodynamic properties of the titles compound were also calculated.

  11. Acetamide herbicides and their degradation products in ground water and surface water of the United States, 1993-2003

    USGS Publications Warehouse

    Scribner, Elisabeth A.; Dietze, Julie E.; Thurman, Michael

    2004-01-01

    During 1993 through 2003, the U.S. Geological Survey conducted a number of studies to investigate and document the occurrence, fate, and transport of acetamide herbicides and their degradation products in ground and surface water. As part of these studies, approximately 5,100 water samples were collected and analyzed for the acetamide parent herbicides acetochlor, alachlor, dimethenamid, flufenacet, and metolachlor and their degradation products ethanesulfonic acid, oxanilic acid, and sulfinyl acetic acid. During this period, various analytical methods were developed to detect and measure concentrations of acetamide herbicides and their degradation products in ground water and surface water. Results showed that the degradation products of acetamide herbicides in ground water were detected more frequently and occurred at higher concentrations than their parent compounds. Further study showed that the acetamide herbicides and their degradation products were detected more frequently in surface water than in ground water. In general, the parent compounds were detected at similar or greater frequencies than the degradation products in surface water. The developed methods and data were valuable for acquiring information about the occurrence, fate, and transport of the herbicides and their degradation products and the importance of analyzing for both parent compounds and their degradate products in water-quality studies.

  12. Interaction of potassium phosphonate fungicide in laterite soil.

    PubMed

    Kumar, R Anil; Velayudhan, K T; Vasu, K; Ramachandran, V; Bhai, R Susheela; Unnikrishnan, G

    2005-10-01

    Potassium phosphonate is a fungicide widely used to control Phytophthora fungi species in many crops all over the world. In this paper, an attempt has been made to study the interaction of potassium phosphonate with soil under varying pH and calcium level. Several reports available in literature indicate that the phosphonate in organic form adsorb strongly on almost all mineral surfaces and natural materials like soil and sediments. The present study conducted on laterite soil of Kerala using 2 mm sieved sample indicated that phosphonate obeys Freundlich adsorption isotherm. Though at lower concentrations, Langmuir model equally fits well, deviation was observed at higher concentrations. pH and calcium content of the soil had striking influence on the interaction of the chemical with the soil. The calcium source also appeared to influence the adsorption phenomenon. Since potassium phosphonate is extensively used to control Phytophthora fungi species in black pepper (Piper nigrum) plantations in India and liming is a standard practice followed as soil amendment in acid soils to increase the soil pH, this study may help to maintain good soil quality. PMID:17051913

  13. A ladder coordination polymer based on Ca(2+) and (4,5-dicyano-1,2-phenylene)bis(phosphonic acid): crystal structure and solution-state NMR study.

    PubMed

    Venkatramaiah, Nutalapati; Mendes, Ricardo F; Silva, Artur M S; Tomé, João P C; Almeida Paz, Filipe A

    2016-09-01

    The preparation of coordination polymers (CPs) based on either transition metal centres or rare-earth cations has grown considerably in recent decades. The different coordination chemistry of these metals allied to the use of a large variety of organic linkers has led to an amazing structural diversity. Most of these compounds are based on carboxylic acids or nitrogen-containing ligands. More recently, a wide range of molecules containing phosphonic acid groups have been reported. For the particular case of Ca(2+)-based CPs, some interesting functional materials have been reported. A novel one-dimensional Ca(2+)-based coordination polymer with a new organic linker, namely poly[[diaqua[μ4-(4,5-dicyano-1,2-phenylene)bis(phosphonato)][μ3-(4,5-dicyano-1,2-phenylene)bis(phosphonato)]dicalcium(II)] tetrahydrate], {[Ca2(C8H4N2O6P2)2(H2O)2]·4H2O}n, has been prepared at ambient temperature. The crystal structure features one-dimensional ladder-like ∞(1)[Ca2(H2cpp)2(H2O)2] polymers [H2cpp is (4,5-dicyano-1,2-phenylene)bis(phosphonate)], which are created by two distinct coordination modes of the anionic H2cpp(2-) cyanophosphonate organic linkers: while one molecule is only bound to Ca(2+) cations via the phosphonate groups, the other establishes an extra single connection via a cyano group. Ladders close pack with water molecules through an extensive network of strong and highly directional O-H...O and O-H...N hydrogen bonds; the observed donor-acceptor distances range from 2.499 (5) to 3.004 (6) Å and the interaction angles were found in the range 135-178°. One water molecule was found to be disordered over three distinct crystallographic positions. A detailed solution-state NMR study of the organic linker is also provided. PMID:27585932

  14. A model study directed towards the preparation of nucleopeptides via H-phosphonate intermediates.

    PubMed Central

    Kuyl-Yeheskiely, E; Tromp, C M; Schaeffer, A H; van der Marel, G A; van Boom, J H

    1987-01-01

    The monofunctional phosphitylating reagents bis-(N,N-diethylamino)chlorophosphine and salicylchlorophosphine have been applied for the preparation of H-phosphonates of the amino acids serine, threonine and tyrosine. Experimental evidence showed that the latter reagent was less effective for the synthesis of a tyrosine H-phosphonate. The amino acids (peptide) H-phosphonates of serine or threonine proved to be suitable starting compounds for the formation of a phosphate diester bond with the 5'-OH of a d-nucleoside derivative using pivaloyl chloride as the activating reagent. PMID:3103103

  15. Synthesis of biologically active phosphonates from Lesquerella oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bisphosphonates and vinyl phosphonates are two classes of compounds that have much potential, namely as pharmaceutical agents and synthetic building blocks. Previous studies have shown success in synthesizing these compounds from hydroxy fatty acids (HFAs) found in Ricinus communis, commonly known a...

  16. Synthesis of glycophostones: cyclic phosphonate analogues of biologically relevant sugars

    PubMed

    Hanessian; Rogel

    2000-05-01

    Analogues of L-fucose, N-acetyl-D-glucosamine, N-acetyl-D-mannosamine, and N-acetyl neuraminic acid in which the anomeric carbon atom was replaced by a phosphonyl group (phostones or cyclic phosphonates) were synthesized by stereocontrolled methods relying on the Abramov reaction. PMID:10808439

  17. 40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., N- - (PMN P-92-31), acetamide, N- - (PMN P-92-32), and acetamide, N- - (PMN P-92-33) are subject to... specified in § 721.80(h). (ii) Release to water. Requirements as specified in § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 90 ppb for PMNs P-92-31 and P-92-32, and N = 30 ppb for P-92-33). When...

  18. 40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., N- - (PMN P-92-31), acetamide, N- - (PMN P-92-32), and acetamide, N- - (PMN P-92-33) are subject to... specified in § 721.80(h). (ii) Release to water. Requirements as specified in § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 90 ppb for PMNs P-92-31 and P-92-32, and N = 30 ppb for P-92-33). When...

  19. Phosphonate derivatives of Methyl oleate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus-containing compounds are often incorporated in lubricants and plastic to improve their properties. In lubricants, phosphonates or diphosphites improve the oxidative stability, anti-wear and extreme pressure properties. In the current work, we describe the synthesis and characterization ...

  20. An atomic force microscopy and molecular simulations study of the inhibition of barite growth by phosphonates

    NASA Astrophysics Data System (ADS)

    Pina, C. M.; Putnis, C. V.; Becker, U.; Biswas, S.; Carroll, E. C.; Bosbach, D.; Putnis, A.

    2004-03-01

    The effect of five phosphonic acids (hydroxyethylene diphosphonic acid, HEDP; nitro trimethyl phosphonic acid, NTMP; methylene diphosphonic acid, MDP; amino methylene phosphonic acid, AMP; and sodium phosphonobutane tricarboxylic acid, PBTC) on the growth of the barite(0 0 1) face has been investigated using atomic force microscopy (AFM). Experimental data have been obtained by in situ measurements of the velocities of barite monomolecular steps growing from solutions with different concentrations of each phosphonic acid. Adsorption isotherms, constructed by plotting individual monomolecular step rates versus inhibitor concentrations, indicate a Langmuir adsorption mechanism in the range of concentrations from 0.5 to 10 μmol/l. Both affinity constants calculated from adsorption isotherms and measurements of growth rates of barite monomolecular steps as a function of inhibitor concentration allowed us to give the following ranking of inhibitor effectiveness: PBTC > NTMP > MDP > HEDP ≫ AMP. Molecular simulations of the interaction of the phosphonic acids with barite(0 0 1) surfaces indicate that only kink sites along monomolecular steps can be considered as possible inhibition sites. This is in agreement with the AFM observations and measurements.

  1. Oxidation Reactivity Channels for 2-(Pyridin-2-yl)-N,N-diphenyl-acetamides

    SciTech Connect

    Pailloux, Sylvie; Binyamin, Iris; Kim, Sung-jun; Deck, Lorraine M.; Rapko, Brian M.; Hay, Benjamin; Duesler, Eileen N.; Paine, Robert T.

    2007-11-01

    Synthetic routes to 2-(pyridin-2-yl)-N,N-diphenylacetamide and 2-(6-methylpyridin-2-yl)-N,N-diphenyl-acetamide are described along with results from the chemical oxidation of these compounds with peracetic acid, m-chloroperbenzoic acid, and OXONE. In each case, oxidations generate four products in varying amounts depending on the oxidant and reaction conditions. Each product has been characterized by spectroscopic methods and the molecular structures of several of the new compounds have been confirmed by X-ray crystallography.

  2. Crystal structures of the apo form and a complex of human LMW-PTP with a phosphonic acid provide new evidence of a secondary site potentially related to the anchorage of natural substrates.

    PubMed

    Fonseca, Emanuella M B; Trivella, Daniela B B; Scorsato, Valéria; Dias, Mariana P; Bazzo, Natália L; Mandapati, Kishore R; de Oliveira, Fábio L; Ferreira-Halder, Carmen V; Pilli, Ronaldo A; Miranda, Paulo C M L; Aparicio, Ricardo

    2015-08-01

    Low molecular weight protein tyrosine phosphatases (LMW-PTP, EC 3.1.3.48) are a family of single-domain enzymes with molecular weight up to 18 kDa, expressed in different tissues and considered attractive pharmacological targets for cancer chemotherapy. Despite this, few LMW-PTP inhibitors have been described to date, and the structural information on LMW-PTP druggable binding sites is scarce. In this study, a small series of phosphonic acids were designed based on a new crystallographic structure of LMW-PTP complexed with benzylsulfonic acid, determined at 2.1Å. In silico docking was used as a tool to interpret the structural and enzyme kinetics data, as well as to design new analogs. From the synthesized series, two compounds were found to act as competitive inhibitors, with inhibition constants of 0.124 and 0.047 mM. We also report the 2.4Å structure of another complex in which LMW-PTP is bound to benzylphosphonic acid, and a structure of apo LMW-PTP determined at 2.3Å resolution. Although no appreciable conformation changes were observed, in the latter structures, amino acid residues from an expression tag were found bound to a hydrophobic region at the protein surface. This regions is neighbored by positively charged residues, adjacent to the active site pocket, suggesting that this region might be not a mere artefact of crystal contacts but an indication of a possible anchoring region for the natural substrate-which is a phosphorylated protein. PMID:26117648

  3. Orientational Jumps in (Acetamide + Electrolyte) Deep Eutectics: Anion Dependence.

    PubMed

    Das, Suman; Biswas, Ranjit; Mukherjee, Biswaroop

    2015-08-27

    All-atom molecular dynamics simulations have been carried out to investigate orientation jumps of acetamide molecules in three different ionic deep eutectics made of acetamide (CH3CONH2) and lithium salts of bromide (Br(–)), nitrate (NO3(–)) and perchlorate (ClO4(–)) at approximately 80:20 mole ratio and 303 K. Orientational jumps have been dissected into acetamide–acetamide and acetamide–ion catagories. Simulated jump characteristics register a considerable dependence on the anion identity. For example, large angle jumps are relatively less frequent in the presence of NO3(–) than in the presence of the other two anions. Distribution of jump angles for rotation of acetamide molecules hydrogen bonded (H-bonded) to anions has been found to be bimodal in the presence of Br(–) and is qualitatively different from the other two cases. Estimated energy barrier for orientation jumps of these acetamide molecules (H-bonded to anions) differ by a factor of ∼2 between NO3(–) and ClO4(–), the barrier height for the latter being lower and ∼0.5kBT. Relative radial and angular displacements during jumps describe the sequence ClO(4)– > NO3(–) > Br(–) and follow a reverse viscosity trend. Jump barrier for acetamide–acetamide pairs reflects weak dependence on anion identity and remains closer to the magnitude (∼0.7kBT) found for orientation jumps in molten acetamide. Jump time distributions exhibit a power law dependence of the type, P(tjump) ∝ A(tjump/τ)(−β), with both β and τ showing substantial anion dependence. The latter suggests the presence of dynamic heterogeneity in these systems and supports earlier conclusions from time-resolved fluorescence measurements. PMID:26131593

  4. Polymorphic Lanthanide Phosphonates Showing Distinct Magnetic Behavior.

    PubMed

    Zeng, Dai; Ren, Min; Bao, Song-Song; Cai, Zhong-Sheng; Xu, Chang; Zheng, Li-Min

    2016-06-01

    A series of layered lanthanide phosphonates α-Ln(2-qpH)(SO4)(H2O)2 (α-Ln; Ln = Gd, Tb, Ho, Er) and β-Ln(2-qpH)(SO4)(H2O)2 (β-Ln; Ln = Gd, Tb, Ho, Er, Yb) (2-qpH2 = 2-quinolinephosphonic acid) have been synthesized and characterized. Compounds α-Ln crystallize in monoclinic space group P21/c, while compounds β-Ln crystallize in triclinic space group P1̅. Magnetic studies reveal that dominant ferromagnetic interactions are propagated between the magnetic centers in all cases. Field-induced magnetic relaxation is observed in compounds β-Er and β-Yb. PMID:27183034

  5. Synthesis of Li-Al layered double hydroxide intercalated with amino tris(methylene phosphonic acid) and kinetic and equilibrium studies of the uptake of Nd3+ and Sr2+ ions

    NASA Astrophysics Data System (ADS)

    Kameda, Tomohito; Shinmyou, Tetsu; Yoshioka, Toshiaki

    2016-03-01

    A Li-Al layered double hydroxide intercalated with amino tris(methylene phosphonic acid) (AMP·Li-Al LDH) was synthesized by the drop-wise addition of an Al-containing solution to a Li-AMP solution at a constant pH of 8.0. The AMP·Li-Al LDH was found to take up Nd3+ and Sr2+ ions from aqueous solutions; this phenomenon was attributable to the metal-chelating functionality of the AMP ions in the interlayers of the AMP·Li-Al LDH. Further, the AMP·Li-Al LDH was found to take up Nd3+ ions preferentially than Sr2+ ions. This was attributable to the stability of the Nd-AMP complex being higher than that of the Sr-AMP complex. The mass-transfer-controlled shrinking-core model could describe the uptake behavior better than the surface-reaction-control model. The AMP ions in the AMP·Li-Al LDH interlayers rapidly formed chelate complexes with the Nd3+ or Sr2+ ions. As a result, the transfer of Nd3+ and Sr2+ ions through the product layer was the rate-limiting step. Furthermore, this reaction could be explained by a Langmuir-type adsorption mechanism, indicating that it involved chemical adsorption; this was consistent with the formation of chelate complexes between Nd3+ and Sr2+ ions and the AMP ions in the interlayers of the AMP·Li-Al LDH.

  6. 40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for... substances and significant new uses subject to reporting. (1) The chemical substances identified as acetamide... reporting under this section for the significant new uses described in paragraph (a)(2) of this section....

  7. 40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for... substances and significant new uses subject to reporting. (1) The chemical substances identified as acetamide... reporting under this section for the significant new uses described in paragraph (a)(2) of this section....

  8. Alpha-carboxy nucleoside phosphonates as universal nucleoside triphosphate mimics

    PubMed Central

    Balzarini, Jan; Das, Kalyan; Bernatchez, Jean A.; Martinez, Sergio E.; Ngure, Marianne; Keane, Sarah; Ford, Alan; Maguire, Nuala; Mullins, Niki; John, Jubi; Kim, Youngju; Dehaen, Wim; Vande Voorde, Johan; Liekens, Sandra; Naesens, Lieve; Götte, Matthias; Maguire, Anita R.; Arnold, Eddy

    2015-01-01

    Polymerases have a structurally highly conserved negatively charged amino acid motif that is strictly required for Mg2+ cation-dependent catalytic incorporation of (d)NTP nucleotides into nucleic acids. Based on these characteristics, a nucleoside monophosphonate scaffold, α-carboxy nucleoside phosphonate (α-CNP), was designed that is recognized by a variety of polymerases. Kinetic, biochemical, and crystallographic studies with HIV-1 reverse transcriptase revealed that α-CNPs mimic the dNTP binding through a carboxylate oxygen, two phosphonate oxygens, and base-pairing with the template. In particular, the carboxyl oxygen of the α-CNP acts as the potential equivalent of the α-phosphate oxygen of dNTPs and two oxygens of the phosphonate group of the α-CNP chelate Mg2+, mimicking the chelation by the β- and γ-phosphate oxygens of dNTPs. α-CNPs (i) do not require metabolic activation (phosphorylation), (ii) bind directly to the substrate-binding site, (iii) chelate one of the two active site Mg2+ ions, and (iv) reversibly inhibit the polymerase catalytic activity without being incorporated into nucleic acids. In addition, α-CNPs were also found to selectively interact with regulatory (i.e., allosteric) Mg2+-dNTP-binding sites of nucleos(t)ide-metabolizing enzymes susceptible to metabolic regulation. α-CNPs represent an entirely novel and broad technological platform for the development of specific substrate active- or regulatory-site inhibitors with therapeutic potential. PMID:25733891

  9. Simultaneous Detection of Cadmium, Copper, and Lead using A Carbon Paste Electrode Modified with Carbamoylphosphonic Acid Self-Assembled Monolayer on Mesoporous Silica (SAMMS)

    SciTech Connect

    Yantasee, Wassana ); Lin, Yuehe ); Fryxell, Glen E. ); Busche, Brad J. )

    2004-01-30

    A new sensor was developed for simultaneous detection of cadmium (Cd2+), copper (Cu2+), and lead (Pb2+), based on the voltammetric response at a carbon paste electrode modified with carbamoylphosphonic acid (acetamide phosphonic acid) self-assembled monolayer on mesoporous silica (Ac-Phos SAMMS). The adsorptive stripping voltammetry technique involves preconcentration of the metal ions onto Ac-Phos SAMMS under an open circuit, then electrolysis of the preconcentrated species, followed by a square wave potential sweep towards positive values. Factors affecting the preconcentration process were investigated. The voltammetric responses increased linearly with the preconcentration time from 1 to 30 minutes or with metal ion concentrations ranging from 10 to 200 ppb. The responses also evolved in the same fashion as adsorption isotherm in the pH range of 2-6. The metal detection limits were 10 ppb after 2 minutes preconcentration and improved to 0.5 ppb after 20 minutes preconcentration.

  10. Changes in concentrations of triazine and acetamide herbicides by bank filtration, ozonation, and chlorination in a public water supply

    USGS Publications Warehouse

    Verstraeten, Ingrid M.; Thurman, E.M.; Lindsey, M.E.; Lee, E.C.; Smith, R.D.

    2002-01-01

    The changes in triazine and acetamide concentrations in water during natural and artificial treatment by bank filtration, ozonation, filtration, and chlorination were measured at the well field and drinking water treatment plant of Lincoln, Nebraska, USA. The city's groundwater supply is affected by induced infiltration and transport of triazines and acetamide herbicides from the Platte River in late spring and early summer. The objective of the study was to evaluate the effect of infiltration and treatment on the presence of triazines and acetamides in drinking water. Samples of river water, well water, and public supply water at various stages of water treatment were collected from 1997-1999 during spring-runoff when the presence of herbicides in the Platte River is largest. In 1999, parent compounds were reduced by 76% of the concentration present in river water (33% by bank filtration, 41% by ozonation, and 1.5% by chlorination). Metabolites of herbicides for which analytical techniques existed were reduced by 21% (plus 26% by bank filtration, minus 23% by ozonation, and minus 24% by chlorination). However, increases in concentrations of specific metabolite compounds were identified after bank filtration and ozonation. After bank filtration, increases in cyanazine amide, cyanazine acid, and deethylcyanazine acid were identified. After ozonation, concentrations of deisopropylatrazine, deethylatrazine, didealkylatrazine, atrazine amide-I, hydroxydeethylatrazine, hydroxydeisopopylatrazine, deethylcyanazine acid, and deethylcyanazine increased. Concentrations of cyanazine acid and ethanesulfonic and oxanilic acids of acetamides decreased during ozonation. Our findings suggest that bank filtration and ozonation of water in part can shift the assessment of risk to human health associated with the consumption of the water from the parent compounds to their degradation products.

  11. The inhibition of crystal growth of mirabilite in aqueous solutions in the presence of phosphonates

    NASA Astrophysics Data System (ADS)

    Vavouraki, A. I.; Koutsoukos, P. G.

    2016-02-01

    The formation of sodium sulfate decahydrate (Mirabilite) has been known to cause serious damages to structural materials both of modern and of historical buildings. Methods which can retard or completely suppress the development of mirabilte crystals are urgently needed especially as remedies or preventive measures for the preservation of the built cultural heritage. In the present work we present results on the effect of the presence of phosphonate compounds on the kinetics of crystal growth from aqueous supersaturated solutions at 18 °C using the seeded growth technique. The phosphonate compounds tested differed with respect to the number of ionizable phosphonate groups and with respect to the number of amino groups in the respective molecules. The crystal growth process was monitored by the temperature changes during the exothermic crystallization of mirabilite in the stirred supersaturated solutions. The crystal growth of mirabilite in the presence of: (1-hydroxyethylidene)-1, 1-diphosphonic acid (HEDP), amino tri (methylene phosphonic acid) (ATMP), hexamethylenediaminetetra (methylene)phosphonic acid (HTDMP), and diethylene triamine penta(methylene phosphonic acid)(DETPMP) over a range of concentrations between 0.1-5% w/w resulted in significant decrease of the rates of mirabilite crystal growth. All phosphonic compounds tested reduced the crystallization rates up to 60% in comparison with additive-free solutions. The presence of the test compounds did not cause changes of the mechanism of crystal growth which was surface diffusion controlled, as shown by the second order dependence of the rates of mirabilite crystal growth on the relative supersaturation. The excellent fit of the measured rates to a kinetic Langmuir-type model suggested that the activity of the tested inhibitors could be attributed to the adsorption and subsequent reduction of the active crystal growth sites of the seed crystals. In all cases, the inhibitory activity was reduced with

  12. Oxygen isotope signature of UV degradation of glyphosate and phosphonoacetate: tracing sources and cycling of phosphonates.

    PubMed

    Sandy, Edward H; Blake, Ruth E; Chang, Sae Jung; Jun, Yao; Yu, Chan

    2013-09-15

    The degradation of phosphonates in the natural environment constitutes a major route by which orthophosphate (Pi) is regenerated from organic phosphorus and recently implicated in marine methane production, with ramifications to environmental pollution issues and global climate change concerns. This work explores the application of stable oxygen isotope analysis in elucidating the CP bond cleavage mechanism(s) of phosphonates by UV photo-oxidation and for tracing their sources in the environment. The two model phosphonates used, glyphosate and phosphonoacetic acid were effectively degraded after exposure to UV irradiation. The isotope results indicate the involvement of both ambient water and atmospheric oxygen in the CP bond cleavage and generally consistent with previously posited mechanisms of UV-photon excitation reactions. A model developed to calculate the oxygen isotopic composition of the original phosphonate P-moiety, shows both synthetic phosphonates having distinctly lower values compared to naturally derived organophosphorus compounds. Such mechanistic models, based on O-isotope probing, are useful for tracing the sources and reactions of phosphonates in the environment. PMID:23892161

  13. Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

    PubMed Central

    Zhou, Xiaoyue; Park, Shin-Hye; Mao, Hongli; Isoshima, Takashi; Wang, Yi; Ito, Yoshihiro

    2015-01-01

    Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by 31P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface. PMID:26366080

  14. Tribological properties of biobased ester phosphonates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three phosphonate derivatives of methyl oleate (MeOl) were chemically synthesized in a radical chain reaction and their physical and tribological properties investigated. The three phosphonates differed from each other in the structure of the alkoxy groups attached to the phosphorous, which were as ...

  15. Hollow cobalt phosphonate spherical hybrid as high-efficiency Fenton catalyst

    NASA Astrophysics Data System (ADS)

    Zhu, Yun-Pei; Ren, Tie-Zhen; Yuan, Zhong-Yong

    2014-09-01

    Organic-inorganic hybrid of cobalt phosphonate hollow nanostructured spheres were prepared in a water-ethanol system through a mild hydrothermal process in the absence of any templates using diethylenetriamine penta(methylene phosphonic acid) as bridging molecule. SEM, TEM and N2 sorption characterization confirmed a hollow spherical micromorphology with well-defined porosity. The structure and chemical states of the hybrid materials were investigated by FT-IR, XPS and thermogravimetric analysis, revealing the homogeneous integrity of inorganic and organic units inside the network. As a heterogeneous catalyst, hollow cobalt phosphonate material exhibited considerable catalytic oxidizing decomposition of methylene blue with sulfate radicals as compared to cobalt phosphonate nanoparticles synthesized in single water system, which could be attributed to enhanced mass transfer and high surface area for the hollow material. Some operational parameters, including pH and reaction temperature, were found to influence the oxidation process. The present results suggest that cobalt phosphonate material can perform as an efficient heterogeneous catalyst for the degradation of organic contaminants, providing insights into the rational design and development of alternative catalysts for wastewater treatment.Organic-inorganic hybrid of cobalt phosphonate hollow nanostructured spheres were prepared in a water-ethanol system through a mild hydrothermal process in the absence of any templates using diethylenetriamine penta(methylene phosphonic acid) as bridging molecule. SEM, TEM and N2 sorption characterization confirmed a hollow spherical micromorphology with well-defined porosity. The structure and chemical states of the hybrid materials were investigated by FT-IR, XPS and thermogravimetric analysis, revealing the homogeneous integrity of inorganic and organic units inside the network. As a heterogeneous catalyst, hollow cobalt phosphonate material exhibited considerable

  16. Synthesis and Structural Studies of Calcium and Magnesium Phosphinate and Phosphonate Compounds

    NASA Astrophysics Data System (ADS)

    Bampoh, Victoria Naa Kwale

    The work presented herein describes synthetic methodologies leading to the design of a wide array of magnesium and calcium based phosphinate and phosphonates with possible applications as bone scaffolding materials or additives to bone cements. The challenge to the chemistry of the alkaline earth phosphonate target compounds includes poor solubility of compounds, and poorly understood details on the control of the metal's coordination environment. Hence, less is known on phosphonate based alkaline earth metal organic frameworks as compared to transition metal phosphonates. Factors governing the challenges in obtaining crystalline, well-defined magnesium and calcium solids lie in the large metal diameters, the absence of energetically available d-orbitals to direct metal geometry, as well as the overall weakness of the metal-ligand bonds. A significant part of this project was concerned with the development of suitable reaction conditions to obtain X-ray quality crystals of the reaction products to allow for structural elucidation of the novel compounds. Various methodologies to aid in crystal growth including hydrothermal methods and gel crystallization were employed. We have used phosphinate and phosphonate ligands with different number of phosphorus oxygen atoms as well as diphosphonates with different linker lengths to determine their effects on the overall structural features. An interesting correlation is observed between the dimensionality of products and the increasing number of donor oxygen atoms in the ligands as we progress from phosphinic acid to the phosphorous acids. As an example, monophosphinate ligand only yielded one-dimensional compounds, whereas the phosphonates crystallize as one and two-dimensional compounds, and the di- and triphosphonate based compounds display two or three-dimensional geometries. This thesis provides a selection of calcium and magnesium compounds with one-dimensional geometry, as represented in a calcium phosphinate to novel

  17. Phosphonate analogue substrates for enolase.

    PubMed

    Anderson, V E; Cleland, W W

    1990-11-20

    Phosphonate analogues in which the bridge between C-2 and phosphorus is a CH2 group are slow substrates for yeast enolase. The pH variation of the kinetic parameters for the methylene analogue of 2-phosphoglycerate suggests that the substrate binds as a dianion and that Mg2+ can bind subsequently only if a metal ligand and the catalytic base are unprotonated. Primary deuterium isotope effects of 4-8 on V/KMg, but ones of only 1.15-1.32 on V for dehydration, show that proton removal to give the carbanion intermediate largely limits V/KMg and that a slow step follows which largely limits V (presumably carbanion breakdown). Since there is a D2O solvent isotope effect on V for the reverse reaction of 5, but not an appreciable one on the forward reaction, it appears that the slow rates with phosphonate analogues result from the fact that the carbanion intermediate is more stable than that formed from the normal substrates, and its reaction in both directions limits V. Increased stability as a result of replacement of oxygen by carbon at C-2 of the carbanion is the expected chemical behavior. PMID:2271661

  18. Hierarchical mesostructured titanium phosphonates with unusual uniform lines of macropores.

    PubMed

    Ma, Tian-Yi; Lin, Xiu-Zhen; Zhang, Xue-Jun; Yuan, Zhong-Yong

    2011-04-01

    Organic-inorganic hybrid materials of mesostructured titanium phosphonates with unusual uniform lines of macropores were synthesized by using bis(hexamethylenetriamine) penta(methylenephosphonic acid) (BHMTPMP) as the coupling molecule, through a one-pot hydrothermal process without any surfactant assistance. A wormhole-like mesostructure and many uniform parallel lines of macropores divided by solid ridges in the same direction were confirmed by N(2) sorption, SEM and TEM observations. This novel macropore architecture has never been observed in other metal phosphonate materials, which may be directly related to the structure nature of BHMTPMP with extra long alkyl chains. The structural characterization of FT-IR and MAS NMR revealed the integrity of organic groups inside the hybrid framework. The hybrid materials were also used as adsorbents for heavy metal ions and CO(2), in order to clarify the impacts of the organic contents and organic types on the physicochemical properties of the synthesized hierarchical macro-/mesoporous phosphonate materials. PMID:21344079

  19. A long-acting and highly selective prostacyclin receptor agonist prodrug, 2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide (NS-304), ameliorates rat pulmonary hypertension with unique relaxant responses of its active form, {4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (MRE-269), on rat pulmonary artery.

    PubMed

    Kuwano, Keiichi; Hashino, Asami; Noda, Kumiko; Kosugi, Keiji; Kuwabara, Kenji

    2008-09-01

    2-{4-[(5,6-Diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide (NS-304) is an orally available, long-acting nonprostanoid prostacyclin receptor (IP receptor) agonist prodrug. In a rat model of pulmonary hypertension induced by monocrotaline (MCT), NS-304 ameliorated vascular endothelial dysfunction, pulmonary arterial wall hypertrophy, and right ventricular hypertrophy, and it elevated right ventricular systolic pressure and improved survival. {4-[(5,6-Diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (MRE-269), the active form of NS-304, is much more selective for the IP receptor than are the prostacyclin analogs beraprost and iloprost, which also have high affinity for the EP(3) receptor. To investigate the effect of receptor selectivity on vasodilation of the pulmonary artery, we assessed the relaxant response to these IP agonists in rats. MRE-269 induced vasodilation equally in large pulmonary arteries (LPA) and small pulmonary arteries (SPA), whereas beraprost and iloprost induced less vasodilation in SPA than in LPA. An EP(3) agonist, sulprostone, induced SPA and LPA vasoconstriction, and an EP(3) antagonist attenuated the vasoconstriction. Beraprost showed EP(3) agonism and induced LPA and SPA vasoconstriction, whereas the EP(3) antagonist inhibited this vasoconstriction and enhanced beraprost- and iloprost-induced SPA vasodilation. These findings suggest that the EP(3) agonism of beraprost and iloprost interfered with the SPA vasodilation resulting from their IP receptor agonism. Endothelium removal markedly attenuated the vasodilation induced by beraprost, but not that induced by MRE-269 or iloprost. Moreover, the vasodilation induced by beraprost and iloprost, but not that induced by MRE-269, was more strongly attenuated in LPA from MCT-treated rats than from normal rats. NS-304 is a promising alternative medication for pulmonary arterial hypertension with prospects for good patient compliance. PMID:18552131

  20. Synthesis of N-(6-Arylbenzo[d]thiazole-2-acetamide Derivatives and Their Biological Activities: An Experimental and Computational Approach.

    PubMed

    Gull, Yasmeen; Rasool, Nasir; Noreen, Mnaza; Altaf, Ataf Ali; Musharraf, Syed Ghulam; Zubair, Muhammad; Nasim, Faiz-Ul-Hassan; Yaqoob, Asma; DeFeo, Vincenzo; Zia-Ul-Haq, Muhammad

    2016-01-01

    A new series of N-(6-arylbenzo[d]thiazol-2-yl)acetamides were synthesized by C-C coupling methodology in the presence of Pd(0) using various aryl boronic pinacol ester/acids. The newly synthesized compounds were evaluated for various biological activities like antioxidant, haemolytic, antibacterial and urease inhibition. In bioassays these compounds were found to have moderate to good activities. Among the tested biological activities screened these compounds displayed the most significant activity for urease inhibition. In urease inhibition, all compounds were found more active than the standard used. The compound N-(6-(p-tolyl)benzo[d]thiazol-2-yl)acetamide was found to be the most active. To understand this urease inhibition, molecular docking studies were performed. The in silico studies showed that these acetamide derivatives bind to the non-metallic active site of the urease enzyme. Structure-activity studies revealed that H-bonding of compounds with the enzyme is important for its inhibition. PMID:26927044

  1. Synthesis, characterization and fuel cell performance tests of boric acid and boron phosphate doped, sulphonated and phosphonated poly(vinyl alcohol) based composite membranes

    NASA Astrophysics Data System (ADS)

    Şahin, Alpay; Ar, İrfan

    2015-08-01

    The aim of this study is to synthesize a composite membrane having high proton conductivity, ion exchange capacity and chemical stability. In order to achieve this aim, poly(vinyl alcohol) (PVA) based composite membranes are synthesized by using classic sol-gel method. Boric acid (H3BO3) and boron phosphate (BPO4) are added to the membrane matrix in different ratios in order to enhance the membrane properties. Characterization tests, i.e; FT-IR analysis, mechanical strength tests, water hold-up capacities, swelling properties, ion exchange capacities, proton conductivities and fuel cell performance tests of synthesized membranes are carried out. As a result of performance experiments highest performance values are obtained for the membrane containing 15% boron phosphate at 0.6 V and 750 mA/cm2. Water hold-up capacity, swelling ratio, ion exchange capacity and proton conductivity of this membrane are found as 56%, 8%, 1.36 meq/g and 0.37 S/cm, respectively. These values are close to the values obtained ones for perfluorosulphonic acid membranes. Therefore this membrane can be regarded as a promising candidate for usage in fuel cells.

  2. Atypical temperature-dependence of symmetry transformation observed in a uranyl phosphonate.

    PubMed

    Zheng, Tao; Gao, Yang; Gui, Daxiang; Chen, Lanhua; Sheng, Daopeng; Diwu, Juan; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

    2016-05-31

    The example of phase transformation from a centrosymmetric space group at low temperature (LT) to a chiral space group at high temperature (HT) is reported, which was clearly resolved in a single-crystal-to-single-crystal manner in a 3D uranyl(vi) phosphonate compound [TMA][(UO2)2(1,3-pbpH)(1,3-pbpH2)] () (TMA(+) = tetramethylammonium cation; 1,3-pbpH4 = 1,3-phenylenebis(phosphonic acid)). PMID:27184289

  3. Phosphonate Based High Nuclearity Magnetic Cages.

    PubMed

    Sheikh, Javeed Ahmad; Jena, Himanshu Sekhar; Clearfield, Abraham; Konar, Sanjit

    2016-06-21

    Transition metal based high nuclearity molecular magnetic cages are a very important class of compounds owing to their potential applications in fabricating new generation molecular magnets such as single molecular magnets, magnetic refrigerants, etc. Most of the reported polynuclear cages contain carboxylates or alkoxides as ligands. However, the binding ability of phosphonates with transition metal ions is stronger than the carboxylates or alkoxides. The presence of three oxygen donor sites enables phosphonates to bridge up to nine metal centers simultaneously. But very few phosphonate based transition metal cages were reported in the literature until recently, mainly because of synthetic difficulties, propensity to result in layered compounds, and also their poor crystalline properties. Accordingly, various synthetic strategies have been followed by several groups in order to overcome such synthetic difficulties. These strategies mainly include use of small preformed metal precursors, proper choice of coligands along with the phosphonate ligands, and use of sterically hindered bulky phosphonate ligands. Currently, the phosphonate system offers a library of high nuclearity transition metal and mixed metal (3d-4f) cages with aesthetically pleasing structures and interesting magnetic properties. This Account is in the form of a research landscape on our efforts to synthesize and characterize new types of phosphonate based high nuclearity paramagnetic transition metal cages. We quite often experienced synthetic difficulties with such versatile systems in assembling high nuclearity metal cages. Few methods have been emphasized for the self-assembly of phosphonate systems with suitable transition metal ions in achieving high nuclearity. We highlighted our journey from 2005 until today for phosphonate based high nuclearity transition metal cages with V(IV/V), Mn(II/III), Fe(III), Co(II), Ni(II), and Cu(II) metal ions and their magnetic properties. We observed that

  4. Selective Removal of Lanthanides from Natural Waters, Acidic Streams and Dialysate

    SciTech Connect

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, Raymond S.; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

    2009-09-15

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, increasing public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd, Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS®) that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (ProPhos), and 1-hydroxy-2-pyridinone (1,2-HOPO) from natural waters (river, ground, and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate and compares their performance to a high surface area activated carbon. The properties include sorption affinity, capacity, and sorption kinetics. Stability and regenerability of SAMMS materials were also investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. While the activated carbon is as effective as 1,2-HOPO-SAMMS for capturing lanthanides in natural (alkaline) waters, it has no affinity in acid solutions (pH 2.4) and low affinity in carbonate-rich dialysate. Over 99% of 100 ug/L of Gd in dialysate was removed by the ProPhos-SAMMS after ten minutes. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties, for a number of regeneration cycles. In acid solutions, PhoPhos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their potential for chromatographic lanthanide separations. Thus, SAMMS materials have a great potential to be used as sorbents in large scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and sorbent dialyzers for lanthanide clearances.

  5. Amino-Functionalized Layered Crystalline Zirconium Phosphonates: Synthesis, Crystal Structure, and Spectroscopic Characterization.

    PubMed

    Taddei, Marco; Sassi, Paola; Costantino, Ferdinando; Vivani, Riccardo

    2016-06-20

    Two new layered zirconium phosphonates functionalized with amino groups were synthesized starting from aminomethylphosphonic acid in the presence of different mineralizers, and their structures were solved from powder X-ray diffraction data. Their topologies are unprecedented in zirconium phosphonate chemistry: the first, of formula ZrH[F3(O3PCH2NH2)], prepared in the presence of hydrofluoric acid, features uncommon ZrO2F4 units and a remarkable thermal stability; the second, of formula Zr2H2[(C2O4)3(O3PCH2NH2)2]·2H2O, prepared in the presence of oxalic acid, is based on ZrO7 units with oxalate anions coordinated to the metal atom, which were never observed before in any zirconium phosphonate. In addition, the structure of another compound based on (2-aminoethyl)phosphonic acid is reported, which was the object of a previously published study. This compound has layered α-type structure with -NH3(+) groups located in the interlayer space. All of the reported compounds were further characterized by means of vibrational spectroscopy, which provided important information on fine structural details that cannot be deduced from the powder X-ray diffraction data. PMID:27254781

  6. Flame Resistant Cotton Durability and Antimicrobial Resistance Properties by using a Novel Epoxy Phosphonate Monomers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently we showed the design, synthesis, characterization, and usefulness of 2-(dimethoxy-phosphorylmethyl)-oxiranylmethyl]-phosphonic acid dimethyl ester that was generated from 3-chloro-2-chloromethylpropene (Polymer Preprints 2005, 46(1), 583-584). This monomer was grafted onto cotton fabrics (...

  7. Selective removal of lanthanides from natural waters, acidic streams and dialysate.

    PubMed

    Yantasee, Wassana; Fryxell, Glen E; Addleman, R Shane; Wiacek, Robert J; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N

    2009-09-15

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 microg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning. PMID:19345006

  8. Selective removal of lanthanides from natural waters, acidic streams and dialysate

    PubMed Central

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

    2009-01-01

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS™), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 µg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning. PMID:19345006

  9. Palladium-Catalyzed α-Arylation of Benzylic Phosphonates

    PubMed Central

    2015-01-01

    A new synthetic route to access diarylmethyl phosphonates is presented. The transformation enables the introduction of aromatic groups on benzylic phosphonates via a deprotonative cross-coupling process (DCCP). The Pd(OAc)2/CataCXium A-based catalyst afforded a reaction between benzyl diisopropyl phosphonate derivatives and aryl bromides in good to excellent isolated yields (64–92%). PMID:24520897

  10. 40 CFR 721.10069 - Ether amine phosphonate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ether amine phosphonate (generic). 721... Substances § 721.10069 Ether amine phosphonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as ether amine phosphonate (PMN...

  11. 40 CFR 721.10069 - Ether amine phosphonate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ether amine phosphonate (generic). 721... Substances § 721.10069 Ether amine phosphonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as ether amine phosphonate (PMN...

  12. Development of Oseltamivir Phosphonate Congeners as Anti-Influenza Agents

    PubMed Central

    Cheng, Ting-Jen R.; Weinheimer, Steven; Tarbet, E. Bart; Jan, Jia-Tsrong; Cheng, Yih-Shyun E.; Shie, Jiun-Jie; Chen, Chun-Lin; Chen, Chih-An; Hsieh, Wei-Che; Huang, Pei-Wei; Lin, Wen-Hao; Wang, Shi-Yun; Fang, Jim-Min; Hu, Oliver Yoa-Pu; Wong, Chi-Huey

    2012-01-01

    Oseltamivir phosphonic acid (tamiphosphor, 3a), its monoethyl ester (3c), guanidino-tamiphosphor (4a) and its monoethyl ester (4c) are potent inhibitors of influenza neuraminidases. They inhibit the replication of influenza viruses, including the oseltamivir-resistant H275Y strain, at low nM to pM levels, and significantly protect mice from infection with lethal doses of influenza viruses when orally administered with 1 mg/kg or higher doses. These compounds are stable in simulated gastric fluid, liver microsomes and human blood, and are largely free from binding to plasma proteins. Pharmacokinetic properties of these inhibitors are thoroughly studied in dogs, rats and mice. The absolute oral bioavailability of these compounds was lower than 12%. No conversion of monoester 4c to phosphonic acid 4a was observed in rats after intravenous administration, but partial conversion of 4c was observed with oral administration. Advanced formulation may be investigated to develop these new anti-influenza agents for better therapeutic use. PMID:23009169

  13. Mechanistic understanding of calcium-phosphonate solid dissolution and scale inhibitor return behavior in oilfield reservoir: formation of middle phase.

    PubMed

    Zhang, Ping; Shen, Dong; Ruan, Gedeng; Kan, Amy T; Tomson, Mason B

    2016-08-01

    Phosphonates are an important class of mineral scale inhibitors used for oilfield scale control. By injecting the phosphonate into an oilfield reservoir, calcium-phosphonate precipitate will form and subsequently release the phosphonate into produced water for scale control. In this study, a systematic procedure is developed to mechanistically characterize an acidic calcium-phosphonate amorphous material that is later developed into a middle phase and eventually a crystalline phase. The phosphonate used in this study is diethylenetriamine pentakis (methylene phosphonic acid) (DTPMP). An amorphous calcium-DTPMP solid is precipitated by mixing a calcium-containing solution with a DTPMP solution. The stoichiometry of this initially formed solid can be experimentally confirmed via a static dissolution test. Following another dynamic development test, two additional Ca-DTPMP solid phases, i.e., a middle phase and a crystalline phase have been observed. Electron microscopy and X-ray diffraction were employed to characterize the morphology and crystallinity of different Ca-DTPMP solids of interest. Evidently, the dynamic brine flushing of the Ca-DTPMP solid developed the initially amorphous material into a middle phase solid with an amorphous/microcrystalline structure and eventually into a crystalline material. Furthermore, a dissolution characterization study was carried out to determine the solubility product of the middle phase solid at different conditions. The obtained mechanistic understanding of the Ca-DTPMP solid related to precipitation chemistry, dissolution behavior and phase transition is critical to elucidate oilfield DTPMP return data and more importantly, can optimize the oilfield scale squeeze design to achieve an extended squeeze lifetime. PMID:27426410

  14. Hydrothermal synthesis and structural characterization of ammonium ion-templated lanthanide(III) carboxylate-phosphonates

    PubMed Central

    Ayi, Ayi A.; Kinnibrugh, Tiffany L.; Clearfield, Abraham

    2014-01-01

    Using N-(phosphonomethyl) iminodiacetic acid (H4PMIDA), as a complexing agent, two new complexes, (NH4)La(PMIDA)(H2O)•H2O, 1 and (NH4)Yb(PMIDA), 2 have been synthesized hydrothermally. In both compounds, the metal ions are trapped by a three five-membered chelate rings by the chelating PMIDA anions giving a tricapped trigonal prismatic LaO8N and monocapped trigonal prismatic YbO6N geometries for 1 and 2, respectively. The structure of 1 consists of La(PMIDA)(H2O) chelating units, linked together by the phosphonate oxygen atoms O1 and O3 to form a chain along the c-axis. The chains are then connected together by the bridging phosphonate oxygen O2 to form a 2D layered structure with alternating 4- and 8-membered apertures. The structure of 2 consists Yb(PMIDA) chelating units, which are connected by alternating bridging carboxylate and phosphonate groups along the [010] direction forming chains with a corrugated pattern. The third phosphonate oxygen bridges the chains together along the [001] direction to build the two-dimensional layer with 4- and 6-membered apertures in the bc-plane. Under excitation of 330 nm, compound 2 shows a broad emission band at λmax = 460 nm. This emission is essentially in the blue luminescent region, which corresponds to ligand centered fluorescence. PMID:25414845

  15. FORMATION OF PEPTIDE BONDS IN SPACE: A COMPREHENSIVE STUDY OF FORMAMIDE AND ACETAMIDE IN Sgr B2(N)

    SciTech Connect

    Halfen, D. T.; Ziurys, L. M.; Ilyushin, V. E-mail: lziurys@as.arizona.edu

    2011-12-10

    Extensive observations of acetamide (CH{sub 3}CONH{sub 2}) and formamide (NH{sub 2}CHO) have been conducted toward Sgr B2(N) at 1, 2, and 3 mm using the Submillimeter Telescope (SMT) and the 12 m antenna of the Arizona Radio Observatory. Over the frequency range 65-280 GHz, 132 transitions of acetamide have been observed as individual, distinguishable features, although in some cases they are partially blended. The unblended transitions in acetamide indicate V{sub LSR} = 63.2 {+-} 2.8 km s{sup -1} and {Delta}V{sub 1/2} = 12.5 {+-} 2.9 km s{sup -1}, line parameters that are very similar to that of formamide (NH{sub 2}CHO) and other organic species in Sgr B2(N). For formamide, 79 individual transitions were identified over the same frequency region. Rotational diagram analyses indicate the presence of two components for both species in Sgr B2(N). For acetamide, the colder component (E{sub u} < 40 K) exhibits a rotational temperature of T{sub rot} = 17 {+-} 4 K and a column density of N{sub tot} = 5.2 {+-} 3.5 Multiplication-Sign 10{sup 13} cm{sup -2}; the higher energy component has T{sub rot} = 171 {+-} 4 K and N{sub tot} = 6.4 {+-} 4.7 Multiplication-Sign 10{sup 14} cm{sup -2}. In the case of formamide, T{sub rot} = 26 {+-} 4 K and N{sub tot} = 1.6 {+-} 0.7 Multiplication-Sign 10{sup 14} cm{sup -2} for the colder component with T{sub rot} = 134 {+-} 17 K and N{sub tot} = 4.0 {+-} 1.2 Multiplication-Sign 10{sup 14} cm{sup -2} for the warmer region. The fractional abundances of acetamide are f (H{sub 2}) = 1.7 Multiplication-Sign 10{sup -11} and 2.1 Multiplication-Sign 10{sup -10} for the cold and warm components, and in formamide, f (H{sub 2}) = 5.3 Multiplication-Sign 10{sup -11} and 1.3 Multiplication-Sign 10{sup -10}. The similarity between the abundances and distributions of CH{sub 3}CONH{sub 2} and NH{sub 2}CHO suggests a synthetic connection. The abundance of acetamide, moreover, is only a factor of three lower than that of formaldehyde, and very similar to

  16. 40 CFR 721.10067 - Ether amine phosphonate salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ether amine phosphonate salt (generic... Specific Chemical Substances § 721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances... ether amine phosphonate salt (PMNs P-05-57, P-05-58, P-05-59, P-05-61, P-05-62, P-05-63, P-05-64, and...

  17. 40 CFR 721.10067 - Ether amine phosphonate salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ether amine phosphonate salt (generic... Specific Chemical Substances § 721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances... ether amine phosphonate salt (PMNs P-05-57, P-05-58, P-05-59, P-05-61, P-05-62, P-05-63, P-05-64, and...

  18. 40 CFR 721.10067 - Ether amine phosphonate salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Ether amine phosphonate salt (generic... Specific Chemical Substances § 721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances... ether amine phosphonate salt (PMNs P-05-57, P-05-58, P-05-59, P-05-61, P-05-62, P-05-63, P-05-64, and...

  19. 40 CFR 721.10067 - Ether amine phosphonate salt (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Ether amine phosphonate salt (generic... Specific Chemical Substances § 721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances... ether amine phosphonate salt (PMNs P-05-57, P-05-58, P-05-59, P-05-61, P-05-62, P-05-63, P-05-64, and...

  20. 40 CFR 721.10067 - Ether amine phosphonate salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Ether amine phosphonate salt (generic... Specific Chemical Substances § 721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances... ether amine phosphonate salt (PMNs P-05-57, P-05-58, P-05-59, P-05-61, P-05-62, P-05-63, P-05-64, and...

  1. In Vivo Bone-Targeting of Bis(phosphonate)-Conjugated Double Helical RNA Monitored by Positron Emission Tomography.

    PubMed

    Jadhav, Satish; Käkelä, Meeri; Bourgery, Matthieu; Rimpilä, Kiira; Liljenbäck, Heidi; Siitonen, Riikka; Mäkilä, Jussi; Laitala-Leinonen, Tiina; Poijärvi-Virta, Päivi; Lönnberg, Harri; Roivainen, Anne; Virta, Pasi

    2016-07-01

    A bis(phosphonate) conjugate of 2'-O-methyl oligoribonucleotide (microRNA-21) was synthesized and used as a bone-targeting carrier in the systemic delivery of a (68)Ga-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA)-chelated 2'-O-methyl oligoribonucleotide (anti-microRNA-21). The whole-body biodistribution of the double helical RNA was monitored by positron emission tomography (PET), which verified the expected bis(phosphonate)-induced bone accumulation in healthy rats. PMID:27218688

  2. Preparation and use of crystalline bis-monoorganic phosphonate and phosphate salts of tetravalent metals

    DOEpatents

    Maya, L.

    1980-06-26

    A method of preparing and using the crystalline organic derivatives of the tetravalent metal phosphates and phosphonates provides for the contacting of an aqueous solution of a metal nitrate, with a solution of an organophosphorus acid for a period of time at room temperature that is sufficient for the formation of a metal phosphate product, and thereafter recovering said product. According to the invention, the product of the disclosed process is used in effecting analytical separations, such as ion exchange and chromatography.

  3. 40 CFR 721.6070 - Alkyl phosphonate ammonium salts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl phosphonate ammonium salts. 721... Substances § 721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant new uses... salts (PMNs P-93-725 and P-93-726) are subject to reporting under this section for the significant...

  4. 40 CFR 721.6070 - Alkyl phosphonate ammonium salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl phosphonate ammonium salts. 721... Substances § 721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant new uses... salts (PMNs P-93-725 and P-93-726) are subject to reporting under this section for the significant...

  5. 40 CFR 721.6070 - Alkyl phosphonate ammonium salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl phosphonate ammonium salts. 721... Substances § 721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant new uses... salts (PMNs P-93-725 and P-93-726) are subject to reporting under this section for the significant...

  6. 40 CFR 721.6070 - Alkyl phosphonate ammonium salts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl phosphonate ammonium salts. 721... Substances § 721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant new uses... salts (PMNs P-93-725 and P-93-726) are subject to reporting under this section for the significant...

  7. 40 CFR 721.6070 - Alkyl phosphonate ammonium salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl phosphonate ammonium salts. 721... Substances § 721.6070 Alkyl phosphonate ammonium salts. (a) Chemical substances and significant new uses... salts (PMNs P-93-725 and P-93-726) are subject to reporting under this section for the significant...

  8. Diversity and abundance of phosphonate biosynthetic genes in nature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphonates, molecules containing direct C-P bonds, comprise a structurally diverse class of natural products with interesting and useful biological properties. Although their synthesis in protozoa was discovered more than fifty years ago, the extent and diversity of phosphonate production in natur...

  9. Antimalarial activity of prodrugs of N-branched acyclic nucleoside phosphonate inhibitors of 6-oxopurine phosphoribosyltransferases.

    PubMed

    Hocková, Dana; Janeba, Zlatko; Naesens, Lieve; Edstein, Michael D; Chavchich, Marina; Keough, Dianne T; Guddat, Luke W

    2015-09-01

    Acyclic nucleoside phosphonates (ANPs) that contain a 6-oxopurine base are good inhibitors of the human and Plasmodium falciparum 6-oxopurine phosphoribosyltransferases (PRTs), key enzymes of the purine salvage pathway. Chemical modifications, based on the crystal structures of several inhibitors in complex with the human PRTase, led to the design of a new class of inhibitors--the aza-ANPs. Because of the negative charges of the phosphonic acid moiety, their ability to cross cell membranes is, however, limited. Thus, phosphoramidate prodrugs of the aza-ANPs were prepared to improve permeability. These prodrugs arrest parasitemia with IC50 values in the micromolar range against Plasmodium falciparum-infected erythrocyte cultures (both chloroquine-sensitive and chloroquine-resistant Pf strains). The prodrugs exhibit low cytotoxicity in several human cell lines. Thus, they fulfill two essential criteria to qualify them as promising antimalarial drug leads. PMID:26275679

  10. A HPLC method for the quantification of butyramide and acetamide at ppb levels in hydrogeothermal waters

    SciTech Connect

    Gracy Elias; Earl D. Mattson; Jessica E. Little

    2012-01-01

    A quantitative analytical method to determine butyramide and acetamide concentrations at the low ppb levels in geothermal waters has been developed. The analytes are concentrated in a preparation step by evaporation and analyzed using HPLC-UV. Chromatographic separation is achieved isocratically with a RP C-18 column using a 30 mM phosphate buffer solution with 5 mM heptane sulfonic acid and methanol (98:2 ratio) as the mobile phase. Absorbance is measured at 200 nm. The limit of detection (LOD) for BA and AA were 2.0 {mu}g L{sup -1} and 2.5 {mu}g L{sup -1}, respectively. The limit of quantification (LOQ) for BA and AA were 5.7 {mu}g L{sup -1} and 7.7 {mu}g L{sup -1}, respectively, at the detection wavelength of 200 nm. Attaining these levels of quantification better allows these amides to be used as thermally reactive tracers in low-temperature hydrogeothermal systems.

  11. Leuckart Synthesis and Pharmacological Assessment of Novel Acetamide Derivatives.

    PubMed

    Rani, Priyanka; Pal, Dilipkumar; Hegde, Rahul Rama; Hashim, Syed Riaz

    2016-01-01

    A new concatenation of N-(1-(4-bromophenyl)ethyl)-2-phenoxyacetamide and N-(1-(4-methoxyphenyl) ethyl)-2-phenoxyacetamide derivatives having 2-phenoxy-N-(1-phenylethyl)acetamide nucleus as common in both the types was synthesized for the sake of achieve titled compounds as potential cytotoxic, anti-inflammatory, analgesic and antipyretic agents. All the novel derivatives have been synthesized through multi-step reaction sequence starting from Leuckart reaction. The structural assignments of the new compounds have been determined by virtue of their IR, 1H NMR, 13C NMR, elemental analysis and mass spectrum analysis. All the synthesized compounds were assessed for cytotoxicity and anti-inflammatory, analgesic and antipyretic effects. Among the series, compounds 3a, 3c, 3g and 3h possess cytotoxic, anti-inflammatory, analgesic and antipyretic activities comparable with standard drugs. The synthesized compounds were found to be active because of the presence of bromo, tert- butyl and nitro groups at position 4 of phenoxy nucleus. PMID:26555612

  12. Acetamides: chemotherapeutic agents for inflammation-associated cancers.

    PubMed

    Rani, Priyanka; Pal, Dilipkumar; Hegde, Rahul Rama; Hashim, Syed Riaz

    2016-08-01

    Now clear evidences are available to support the hypothesis that inflammation accelerates the conditions including events and molecules that reach to various types of cancers. Inflammation is a normal response to infection containing the innate and adaptive immune systems. However, when allowed to continue, unresolved, perturbation of cellular microenvironment takes place; therefore, it leads to adaptations in genes that are linked to cancer. In addition, a lot of data are accessible confirming the concept that tumour microenvironment is orchestrated by various inflammatory cells and goes to neoplastic process and finally invasion, migration and metastasis. However, infiltrations of leucocytes lead to angiogenesis, propagation and invasion. An inflammatory microenvironment that perhaps fostering impact of angiogenesis include cytokines, chemokines, enzymes and growth factors that play key role for expansion and invasion of cancer cells. This insight highlights the pathogenesis of inflammation-associated cancers and also touches and fosters the role of acetamides for the treatment and chemoprevention of carcinomas that are allied with inflammation. PMID:26198312

  13. 3,6-O-[N-(2-Aminoethyl)-acetamide-yl]-chitosan exerts antibacterial activity by a membrane damage mechanism.

    PubMed

    Yan, Feilong; Dang, Qifeng; Liu, Chengsheng; Yan, Jingquan; Wang, Teng; Fan, Bing; Cha, Dongsu; Li, Xiaoli; Liang, Shengnan; Zhang, Zhenzhen

    2016-09-20

    A novel chitosan derivative, 3,6-O-[N-(2-aminoethyl)-acetamide-yl]-chitosan (AACS), was successfully prepared to improve water solubility and antibacterial activity of chitosan. AACS had good antibacterial activity, with minimum inhibitory concentrations of 0.25mg/mL, against Escherichia coli and Staphylococcus aureus. Cell membrane integrity, electric conductivity and NPN uptake tests showed that AACS caused quickly increasing the release of intracellular nucleic acids, the uptake of NPN, and the electric conductivity by damaging membrane integrity. On the other hand, hydrophobicity, cell viability and SDS-PAGE experiments indicated that AACS was able to reduce the surface hydrophobicity, the cell viability and the intracellular proteins through increasing membrane permeability. SEM observation further confirmed that AACS could kill bacteria via disrupting their membranes. All results above verified that AACS mainly exerted antibacterial activity by a membrane damage mechanism, and it was expected to be a new food preservative. PMID:27261735

  14. Phase Behavior and Conductivity of Phosphonated Block Copolymers Containing Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Jung, Ha Young; Kim, Sung Yeon; Park, Moon Jeong

    2015-03-01

    As the focus on proton exchange fuel cells continues to escalate in the era of alternative energy systems, the rational design of sulfonated polymers has emerged as a key technique for enhancing device efficiency. While the sulfonic acid group guarantees high proton conductivity of membranes under humidified conditions, the growing need for high temperature operation has discouraged their practical uses in fuel cells. In this respect, phosphonated polymers have drawn intensive attention in recent years owing to their self-dissociation ability. In this study, we have synthesized a set of phosphonated block copolymers, poly(styrenephosphonate-methylbutylene) (PSP- b - PMB), by varying phosphonation level (PL). A wide variety of self-assembled morphologies, i.e., disordered, lamellar, hexagonally perforated lamellae and hexagonally packed cylindrical phases, were observed with PL. Remarkably, upon comparing the morphology of PSP- b-PMB and that of sulfonated analog, we found distinctly dissimilar domain sizes at the same molecular weight and composition. A range of ionic liquids (ILs) were incorporated into the PSP- b-PMB block copolymers and their ion transport properties were examined. It has been revealed that the degree of confinement of ionic phases (domain size) impacts the ion mobility and proton dissociation efficiency of IL-containing polymers.

  15. Phosphonate-Derived Nanoporous Metal Phosphates and Their Superior Energy Storage Application.

    PubMed

    Pramanik, Malay; Salunkhe, Rahul R; Imura, Masataka; Yamauchi, Yusuke

    2016-04-20

    Nanoporous nickel, aluminum, and zirconium phosphates (hereafter, abbreviated as NiP, AlP, and ZrP, respectively) with high surface areas and controlled morphology and crystallinity have been synthesized through simple calcination of the corresponding phosphonates. For the preparation of phosphonate materials, nitrilotris(methylene)triphosphonic acid (NMPA) is used as phosphorus source. The organic component in the phosphonate materials is thermally removed to form nanoporous structures in the final phosphate materials. The formation mechanism of nanoporous structures, as well as the effect of applied calcination temperatures on the morphology and crystallinity of the final phosphate materials, is carefully discussed. Especially, nanoporous NiP materials have a spherical morphology with a high surface area and can have great applicability as an electrode material for supercapacitors. It has been found that there is a critical effect of particle sizes, surface areas, and the crystallinities of NiP materials toward electrochemical behavior. Our nanoporous NiP material has superior specific capacitance, as compared to various phosphate nanomaterials reported previously. Excellent retention capacity of 97% is realized even after 1000 cycles, which can be ascribed to its high structural stability. PMID:27028363

  16. Diversity and abundance of phosphonate biosynthetic genes in nature

    PubMed Central

    Yu, Xiaomin; Doroghazi, James R.; Janga, Sarath C.; Zhang, Jun Kai; Circello, Benjamin; Griffin, Benjamin M.; Labeda, David P.; Metcalf, William W.

    2013-01-01

    Phosphonates, molecules containing direct carbon–phosphorus bonds, compose a structurally diverse class of natural products with interesting and useful biological properties. Although their synthesis in protozoa was discovered more than 50 y ago, the extent and diversity of phosphonate production in nature remains poorly characterized. The rearrangement of phosphoenolpyruvate (PEP) to phosphonopyruvate, catalyzed by the enzyme PEP mutase (PepM), is shared by the vast majority of known phosphonate biosynthetic pathways. Thus, the pepM gene can be used as a molecular marker to examine the occurrence and abundance of phosphonate-producing organisms. Based on the presence of this gene, phosphonate biosynthesis is common in microbes, with ∼5% of sequenced bacterial genomes and 7% of genome equivalents in metagenomic datasets carrying pepM homologs. Similarly, we detected the pepM gene in ∼5% of random actinomycete isolates. The pepM-containing gene neighborhoods from 25 of these isolates were cloned, sequenced, and compared with those found in sequenced genomes. PEP mutase sequence conservation is strongly correlated with conservation of other nearby genes, suggesting that the diversity of phosphonate biosynthetic pathways can be predicted by examining PEP mutase diversity. We used this approach to estimate the range of phosphonate biosynthetic pathways in nature, revealing dozens of discrete groups in pepM amplicons from local soils, whereas hundreds were observed in metagenomic datasets. Collectively, our analyses show that phosphonate biosynthesis is both diverse and relatively common in nature, suggesting that the role of phosphonate molecules in the biosphere may be more important than is often recognized. PMID:24297932

  17. Synthesis and local anaesthetic activity of 2-substituted-N-(2-diethylaminoethyl)-acetamides.

    PubMed

    Jindal, Dharam Paul; Coumar, Mohane S; Singh, Babita; Ismail, Mohammed Muhiyiden Mohammed; Zambare, Girish Nilkanth; Bodhankar, Subhash Laxmanrao

    2003-01-01

    The synthesis of 2-substituted-N-(2-diethylaminoethyl)acetamide oxalates (6a, 6b) and the evaluation of their in vivo local anaesthetic activities are described. The compounds 6a and 6b were obtained starting from 4-acetamidophenol and 1-naphthol, respectively. The in vivo local anesthetic activity was evaluated by infiltration anaesthesia, sciatic nerve block and corneal anaesthesia models. N-(2-Diethylaminoethyl)-2-(naphthalen-1-yloxy)acetamide oxalate (6b) was found to have potency, onset and duration of action comparable to that of lidocaine (2) (lidocaine hydrochloride, CAS 6108-05-0). Procaine (1) (procaine hydrochloride, CAS 51-05-8) was also used for comparison. Dissociation constants (pKa) of compounds 5a and 5b (2-substituted-N-(2-diethylaminoethyl)acetamide) have been determined to be 8.9 and 8.6, respectively. PMID:12608012

  18. New structure-activity relationships of N-acetamide substituted pyrazolopyrimidines as pharmacological ligands of TSPO.

    PubMed

    Li, Jun; Schulte, Michael L; Nickels, Michael L; Manning, H Charles

    2016-08-01

    Translocator protein (TSPO) represents an attractive target for molecular imaging and therapy due to its prevalence and critical roles played in oncology and other pathologies. Based upon our previously optimized pyrazolopyrimidine scaffold, we elucidated new structure activity relationships related to N,N-disubstitutions of the terminal acetamide on pyrazolopyrimidines and further explored the impacts of these substituents on lipophilicity and plasma protein binding. Several novel chemical probes reported here exhibited significantly increased binding affinity, suitable lipophilicity and protein binding compared with contemporary TSPO ligands. We illustrate that N,N-acetamide disubstitution affords opportunities to introduce diverse chemical moieties distal to the central pyrazolopyrimidine core, without sacrificing TSPO affinity. We anticipate that further exploration of N-acetamide substitutions may yield additional TSPO ligands capable of furthering the field of precision medicine. PMID:27353534

  19. Chemoselective recognition with phosphonate cavitands: the ephedrine over pseudoephedrine case.

    PubMed

    Biavardi, Elisa; Ugozzoli, Franco; Massera, Chiara

    2015-02-25

    Complete discrimination of ephedrine and pseudoephedrine, both in solution and in the solid state, was achieved with a phosphonate cavitand receptor. The molecular origin of the epimer discrimination was revealed by the crystal structure of the respective complexes. PMID:25625304

  20. Medicinal chemistry of fluorinated cyclic and acyclic nucleoside phosphonates.

    PubMed

    Baszczyňski, Ondřej; Janeba, Zlatko

    2013-11-01

    The fluorine atom plays an important role in medicinal chemistry because fluorine substitution has a strong impact on the physical, chemical, and biological properties of bioactive compounds. Such fluorine modifications have also been extensively studied among the pharmaceutically important class of nucleoside phosphonates, nucleotide analogues in which the phosphate group is replaced by the enzymatically and chemically stable phosphonate moiety. The fluorinated nucleoside phosphonates abound with antiviral, antiparasitic, and anticancer properties because they are able to act as inhibitors of important enzymes of nucleoside/nucleotide metabolism. In this paper, we review the biological properties of cyclic and acyclic nucleoside phosphonates modified by the attachment of one or more fluorine atoms to various parts of the molecule, namely to nucleobases, alkylphosphonate groups, cyclic or acyclic linkers, or to prodrug moieties. PMID:23893552

  1. Slow-to-fast transition of hydrogen bond dynamics in acetamide hydration shell formation.

    PubMed

    D'Amico, Francesco; Rossi, Barbara; Camisasca, Gaia; Bencivenga, Filippo; Gessini, Alessandro; Principi, Emiliano; Cucini, Riccardo; Masciovecchio, Claudio

    2015-04-28

    The formation of a hydration shell in acetamide aqueous solution has been investigated by means of UV Raman spectroscopy. The experimental results reveal the existence of two distinct regimes of water dynamics. At high acetamide concentration water molecules show a structural and dynamical behavior consistent with the so-called iceberg model. Upon increasing the amount of water we observe the formation of a hydration shell marked by fastening of hydrogen-bond dynamics. Such a behavior may help to shed light on the scientific debate on how water rearranges around the hydrophobic portions of solute molecules (iceberg vs. non-iceberg models). PMID:25824617

  2. Betulin Phosphonates; Synthesis, Structure, and Cytotoxic Activity.

    PubMed

    Chrobak, Elwira; Bębenek, Ewa; Kadela-Tomanek, Monika; Latocha, Małgorzata; Jelsch, Christian; Wenger, Emmanuel; Boryczka, Stanisław

    2016-01-01

    Betulin derivatives are a widely studied group of compounds of natural origin due to their wide spectrum of biological activities. This paper describes new betulin derivatives, containing a phosphonate group. The allyl-vinyl isomerization and synthesis of acetylenic derivatives have been reported. Structural identification of products as E and Z isomers has been carried out using ¹H-, (13)C-, (31)P-NMR, and crystallographic analysis. The crystal structure in the orthorhombic space group and analysis of crystal packing contacts for 29-diethoxyphosphoryl-28-cyclopropylpropynoyloxy-lup-20E(29)-en-3β-ol 8a are reported. All new compounds were tested in vitro for their antiproliferative activity against human T47D (breast cancer), SNB-19 (glioblastoma), and C32 (melanoma) cell lines. PMID:27571057

  3. Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

    PubMed Central

    Nasomjai, Pitak; Slawin, Alexandra M Z

    2009-01-01

    Summary The synthesis of phosphonate analogues of ribose-1-phosphate and 5-fluoro-5-deoxyribose-1-phosphate is described. Preparations of both the α- and β-phosphonate anomers are reported for the ribose and 5-fluoro-5-deoxyribose series and a synthesis of the corresponding cyclic phostones of each α-ribose is also reported. These compounds have been prepared as tools to probe the details of fluorometabolism in S. cattleya. PMID:19777136

  4. Reactivity of vinyl phosphonate containing diazoesters: formation, reactivity, and utility.

    PubMed

    Wang, Jin; Rainier, Jon D

    2015-01-16

    Treatment of diazo vinyl phosphonate with alcohols, amines, and thiols in the presence of Rh(II) results in the chemo- and stereoselective generation of enol ethers, enamines and vinyl sulfides via an X-H insertion process. The utility of the products from these reactions was demonstrated through their conversion into quaternary substituted heterocycles including furans and oxetanes as highlighted by the generation of a bicyclic phosphonate analogue of neodysiherbaine. PMID:25534147

  5. A new chiral uranyl phosphonate framework consisting of achiral building units generated from ionothermal reaction: structure and spectroscopy characterizations.

    PubMed

    Zheng, Tao; Gao, Yang; Chen, Lanhua; Liu, Zhiyong; Diwu, Juan; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

    2015-11-01

    The ionothermal reactions of uranyl nitrate and 1,3-pbpH4 (1,3-pbpH4 = 1,3-phenylenebis(phosphonic acid) ligand in ionic liquids of [C4mim][Dbp], [C4mpyr][Br], and [Etpy][Br], respectively, afforded three new uranyl phosphonates, namely [C4mim][(UO2)2(1,3-pbpH)(1,3-pbpH)·Hmim] (1), [UO2(1,3-pbpH2)H2O·mpr] (2), and [Etpy][UO2(1,3-pbpH2)F] (3). Compound 1 exhibits a rare example of a chiral uranyl phosphonate 3D framework structure built from achiral building units of tetragonal bipyramidal uranium polyhedra and 1,3-pbp ligands. The structure adopts a network with channels extending along the b axis, which are filled with C4mim(+) and protonated 1-methylimidazole. In sharp contrast, compounds 2 & 3 both show pillared topology composed of uranyl pentagonal bipyramid polyhedra and phosphonate ligands. The layers are neutral in compound 2 with N-methylpyrrole molecules in the interlayer space, while compound 3 adopts anionic layer, and the charge is compensated with N-ethyl-pyridinium cations between the layers. Although compounds 1, 2, and 3 were synthesized under identical conditions with sole variation of the ionic liquid species, the resulting structures show a rich diversity in the local coordination environment of uranyl ions, the protonation of the phosphonate ligand, the conformation of ionic liquid ions, and the overall arrangement of the structure. All compounds were characterized by absorption, temperature dependent fluorescence, as well as infrared and Raman spectroscopies. PMID:26419426

  6. Tunneling Spectroscopy Studies of Urea, Thiourea, and Selected Phosphonate Molecules Adsorbed on Aluminum Oxide

    NASA Astrophysics Data System (ADS)

    Crowder, Charles D.

    Experimental and calculated inelastic electron tunneling intensities were compared for several of the vibrational modes of thiourea adsorbed on aluminum oxide. The partial charge model of Kirtley, Scalapino, and Hansma was used to compute the theoretical intensities of each mode. The required partial charges were determined using a method developed by Momany. Essentially, the Coulomb potential resulting from point charges located at atom sites was fitted to the quantum mechanical electrostatic potential of a molecule calculated from Hartree-Fock theory. The effect of a vibrational mode pattern on the electrostatic potential of a molecule was investigated. This effect could not be acceptably modeled with a single point charge located on each atom, so one charge was used to represent the positive nucleus of each atom and a second charge was used to represent the valence cloud. The valence charge was allowed to move independently of the nuclear charge during a molecular vibration, and the motions of the two charges were found to be very different for hydrogen atoms. This model gave very reasonable agreement between the theoretical and observed relative intensities for the in plane vibrational modes of thiourea. An acceptable set of out of plane force constants could not be found. This caused problems in the interpretation of the out of plane relative intensities. Based on the in plane modes, it was concluded that thiourea bonded to aluminum oxide with the sulfur atom near the oxide and the sulfur-carbon bond perpendicular to the aluminum oxide surface. Quantum mechanical electrostatic potentials were also calculated for urea, phosphoric acid (PA), methylphosphonic acid (MPA), hydroxymethylphosphonic acid (HMP), and nitrotrismethylphosphonic acid (NTMP). Electron tunneling spectra were taken for PA, HMP and NTMP, and the observed frequencies were compared to values obtained from Fourier transform infrared, infrared and Raman spectroscopy. Upward shifts in the P=O and P

  7. Inorganic resist materials based on zirconium phosphonate for atomic force microscope lithography

    NASA Astrophysics Data System (ADS)

    Kang, Mankyu; Kim, Seonae; Jung, JinHyuck; Kim, Heebom; Shin, Inkyun; Jeon, Chanuk; Lee, Haiwon

    2014-03-01

    New inorganic resist materials based on metal complexes were investigated for atomic force microscope (AFM) lithography. Phosphoric acids are good for self-assembly because of their strong binding energy. In this work, zirconium phosphonate system are newly synthesized for spin-coatable materials in aqueous solutions and leads to negative tone pattern for improving line edge roughness. Low electron exposure by AFM lithography could generate a pattern by electrochemical reaction and cross-linking of metal-oxo complexes. It has been reported that the minimum pattern results are affected by lithographic speed, and the applied voltage between a tip and a substrate.

  8. Inhibition of adenosine kinase by phosphonate and bisphosphonate derivatives.

    PubMed

    Park, Jae; Singh, Bhag; Gupta, Radhey S

    2006-02-01

    The enzyme adenosine kinase (AK) plays a central role in regulating the intracellular and interstitial concentration of the purine nucleoside adenosine (Ado). In view of the beneficial effects of Ado in protecting tissues from ischemia and other stresses, there is much interest in developing AK inhibitors, which can regulate Ado concentration in a site- and event-specific manner. The catalytic activity of AK from different sources is dependent upon the presence of activators such as phosphate (Pi). In this work we describe several new phosphorylated compounds which either activate or inhibit AK. The compounds acetyl phosphate, carbamoyl phosphate, dihydroxyacetone phosphate and imidodiphosphate were found to stimulate AK activity in a dose-dependent manner comparable to that seen with Pi. In contrast, a number of phosphonate and bisphosphonate derivatives, which included clodronate and etidronate, were found to inhibit the activity of purified AK in the presence of Pi. These AK inhibitors (viz. clodronate, etidronate, phosphonoacetic acid, 2-carboxyethylphosphonic acid, N-(phosphonomethyl)-glycine and N-(phosphonomethyl)iminodiacetic acid), at concentrations at which they inhibited AK, were also shown to inhibit the uptake of (3)H-adenosine and its incorporation into macromolecules in cultured mammalian cells, indicating that they were also inhibiting AK in intact cells. The drug concentrations at which these effects were observed showed limited toxicity to the cultured cells, indicating that these effects are not caused by cellular toxicity. These results indicate that the enzyme AK provides an additional cellular target for the clinically widely used bisphosphonates and related compounds, which could possibly be exploited for a new therapeutic application. Our structure-activity studies on different AK activators and inhibitors also indicate that all of the AK activating compounds have a higher partial positive charge (delta(+)) on the central phosphorous atom in

  9. Crystal structures of two (±)-exo-N-isobornyl­acetamides

    PubMed Central

    Stepanovs, Dmitrijs; Posevins, Daniels; Turks, Maris

    2015-01-01

    The title compounds consist of a bornane skeleton with attached acetamide, C12H21NO (±)-(1) {systematic name: (±)-N-[(1RS,2RS,4RS)-1,7,7-tri­methylbi­cyclo­[2.2.1]heptan-2-yl]acetamide}, and chloro­acetamide, C12H20ClNO (±)-(2) {systematic name: (±)-2-chloro-N-[(1RS,2RS,4RS)-1,7,7-tri­methylbi­cyclo­[2.2.1]heptan-2-yl]­acetamide}, functionalities to the 2-exo-position. The crystal structure of the first monoclinic polymorph of (±)-(1) has been reported previously [Ung et al. (2014 ▸). Monatsh. Chem. 145, 983–992]. Compound (±)-(1) crystallizes in the space group P21/n with two independent mol­ecules in the asymmetric unit, in contrast to the above-mentioned polymorph which crystallized in the space group C2/c with one mol­ecule in the asymmetric unit. In the title compounds, the bicyclic bornane moieties have normal geometries. In the crystals of both compounds, mol­ecules are linked by N—H⋯O hydrogen bonds, reinforced by C—H⋯O contacts, forming trans-amide chains propagating along the a-axis direction. In the case of compound (±)-(1), neighbouring chains are linked by further C—H⋯O contacts, forming double-chain ribbons along [100]. PMID:26594386

  10. 40 CFR 721.225 - 2-Chloro-N-methyl-N-substituted acetamide (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 2-Chloro-N-methyl-N-substituted... Specific Chemical Substances § 721.225 2-Chloro-N-methyl-N-substituted acetamide (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance...

  11. 40 CFR 721.225 - 2-Chloro-N-methyl-N-substituted acetamide (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2-Chloro-N-methyl-N-substituted... Specific Chemical Substances § 721.225 2-Chloro-N-methyl-N-substituted acetamide (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance...

  12. 40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is...

  13. 40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is...

  14. 40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is...

  15. 40 CFR 721.225 - 2-Chloro-N-methyl-N-substituted acetamide (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 2-Chloro-N-methyl-N-substituted... Specific Chemical Substances § 721.225 2-Chloro-N-methyl-N-substituted acetamide (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance...

  16. 40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical...

  17. 40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical...

  18. Parametrisation of a force field of acetamide for simulations of the liquid phase

    NASA Astrophysics Data System (ADS)

    Aguilar-Pineda, Jorge A.; Arlette Méndez-Maldonado, G.; Núñez-Rojas, Edgar; Alejandre, José

    2015-09-01

    Molecular dynamics simulations are performed to develop new parameters for acetamide using a systematic procedure proposed by Salas et al., where the atomic charges were fitted to reproduce the experimental dielectric constant and the Lennard-Jones parameters to match the surface tension and density. The parameters for formamide recently calculated by Pérez et al. were used to obtain the new parameters of acetamide where atoms of the amine group and carbon kept the same intermolecular parameter values in both molecules. The parameters of the methyl group, taken as united atom, and the oxygen atom were fitted to reproduce the dielectric constant, surface tension and density at 358.15 K. The new set of parameters, based on the optimised potential for liquids simulations with all atoms, was able to predict results of the target properties as a function of temperature as a pure component and the dielectric constant and density of binary mixtures with water and formamide as a function of acetamide concentration at 298.15 K. The polymer chains formed by hydrogen bond interactions were analysed to understand the maximum of dielectric constant in acetamide-water mixtures.

  19. Indole-3-Acetic Acid Biosynthesis in Colletotrichum gloeosporioides f. sp. aeschynomene

    PubMed Central

    Robinson, M.; Riov, J.; Sharon, A.

    1998-01-01

    We characterized the biosynthesis of indole-3-acetic acid by the mycoherbicide Colletotrichum gloeosporioides f. sp. aeschynomene. Auxin production was tryptophan dependent. Compounds from the indole-3-acetamide and indole-3-pyruvic acid pathways were detected in culture filtrates. Feeding experiments and in vitro assay confirmed the presence of both pathways. Indole-3-acetamide was the major pathway utilized by the fungus to produce indole-3-acetic acid in culture. PMID:9835603

  20. Zirconium(IV)-Benzene Phosphonate Coordination Polymers: Lanthanide and Actinide Extraction and Thermal Properties.

    PubMed

    Luca, Vittorio; Tejada, Juan J; Vega, Daniel; Arrachart, Guilhem; Rey, Cyrielle

    2016-08-15

    Coordination polymers with different P/(Zr + P) molar ratios were prepared by combining aqueous solutions of Zr(IV) and benzenephosphonate derivatives. 1,3,5-Benzenetrisphosphonic acid (BTP) as well as phosphonocarboxylate derivatives in which carboxylate substitutes one or two of the phosphonate groups were chosen as the building blocks. The precipitates obtained on combining the two solutions were not X-ray amorphous but rather were indicative of poorly ordered materials. Hydrothermal treatment did not alter the structure of the materials produced but did result in improved crystalline order. The use of HF as a mineralizing agent during hydrothermal synthesis resulted in the crystallization of at least three relatively crystalline phases whose structure could not be determined owing to the complexity of the diffraction patterns. Gauging from the similarity of the diffraction patterns of all the phases, the poorly ordered precipitates and crystalline materials appeared to have similar underlying structures. The BTP-based zirconium phosphonates all showed a higher selectivity for lanthanides and thorium compared with cations such as Cs(+), Sr(2+), and Co(2+). Substitution of phosphonate groups by carboxylate groups did little to alter the pattern of selectivity implying that selectivity in the system was entirely determined by the -POH group with little influence from the -COOH groups. Samples with the highest phosphorus content showed the highest extraction efficiencies for lanthanide elements, especially the heavy lanthanides such as Dy(3+) and Ho(3+) with separation factors of around four with respect to La(3+). In highly acid solutions (4 M HNO3) there was a pronounced variation in extraction efficiency across the lanthanide series. In situ, nonambient diffraction was performed on ZrBTP-0.8 loaded with Th, Ce, and a complex mixture of lanthanides. In all cases the crystalline Zr2P2O7 pyrophosphate phase was formed at ∼800 °C demonstrating the versatility of

  1. Synthesis and biological evaluation of a phosphonate analog of the natural acetyl cholinesterase inhibitor cyclophostin.

    PubMed

    Bandyopadhyay, Saibal; Dutta, Supratik; Spilling, Christopher D; Dupureur, Cynthia M; Rath, Nigam P

    2008-11-01

    Two diastereomers of a phosphonate analog 6 of the AChE inhibitor cyclophostin were synthesized. The substitution reaction of phosphono allylic carbonate 10a with methyl acetoacetate gave the vinyl phosphonate 9a. Attempted hydrogenation/debenzylation gave an unexpected enolether lactone. Alternatively, selective hydrogenation, demethylation, cyclization and debenzylation gave the phosphonate analog of cyclophostin as a separable mixture of diastereomers 6. The trans phosphonate isomer was more active than the cis isomer against AChE from two sources. PMID:18821801

  2. Analysis of UDP-D-apiose/UDP-D-xylose synthase-catalyzed conversion of UDP-D-apiose phosphonate to UDP-D-xylose phosphonate: implications for a retroaldol-aldol mechanism.

    PubMed

    Choi, Sei-hyun; Mansoorabadi, Steven O; Liu, Yung-nan; Chien, Tun-Cheng; Liu, Hung-wen

    2012-08-29

    UDP-D-apiose/UDP-D-xylose synthase (AXS) catalyzes the conversion of UDP-D-glucuronic acid to UDP-D-apiose and UDP-D-xylose. An acetyl-protected phosphonate analogue of UDP-D-apiose was synthesized and used in an in situ HPLC assay to demonstrate for the first time the ability of AXS to interconvert the two reaction products. Density functional theory calculations provided insight into the energetics of this process and the apparent inability of AXS to catalyze the conversion of UDP-D-xylose to UDP-D-apiose. The data suggest that this observation is unlikely to be due to an unfavorable equilibrium but rather results from substrate inhibition by the most stable chair conformation of UDP-D-xylose. The detection of xylose cyclic phosphonate as the turnover product reveals significant new details about the AXS-catalyzed reaction and supports the proposed retroaldol-aldol mechanism of catalysis. PMID:22830643

  3. Structural characterization and electrochemical properties of novel salicylidene phosphonate derivatives

    NASA Astrophysics Data System (ADS)

    Dolaz, Mustafa; McKee, Vickie; Köse, Muhammet; Gölcü, Ayşegül; Tümer, Mehmet

    2010-09-01

    In this study, three novel salicylidene phosphonate ligands, diethyl (4-{[(1 E)-(2-hydroxyphenyl)methylidene]amino}benzyl)phosphonate (HL 1), diethyl (4-{[(1 E)-(2-hydroxy-3-methoxyphenyl)methylidene]amino}benzyl)phosphonate (HL 2) and diethyl (4-{[(1 E)-(2,4-dihydroxyphenyl)methylidene]amino}benzyl)phosphonate (HL 3) were synthesized and characterized by the analytical and spectroscopic techniques. We obtained their single crystals from the ethanolic solution. There are intramolecular phenol-imine hydrogen bonds in all three compounds between O1 and N1 atoms. The ligand HL 3 contains a second phenol group and this is makes an intermolecular hydrogen bond with the phosphine oxide of a neighbouring molecule O2-O3 (under symmetry operation - x, 0.5 + y, 0.5 - z). In order to investigate the redox behaviours of the salicylidene phosphonate ligands (HL 1-HL 3), we were studied electrochemical properties of the ligands at the different pH and scan rates.

  4. Enhancing the Imaging and Biosafety of Upconversion Nanoparticles through Phosphonate Coating

    PubMed Central

    Li, Ruibin; Ji, Zhaoxia; Dong, Juyao; Chang, Chong Hyun; Wang, Xiang; Sun, Bingbing; Wang, Meiying; Liao, Yu-Pei; Zink, Jeffrey I.; Nel, Andre E.; Xia, Tian

    2015-01-01

    Upconversion nanoparticles (UCNPs), which are generated by doping with rare earth (RE) metals, are increasingly used for bio-imaging because of the advantages they hold over conventional fluorophores. However, because pristine RE nanoparticles (NPs) are unstable in acidic physiological fluids (e.g., lysosomes), leading to intracellular phosphate complexation with the possibility of the lysosomal injury, it is important to ensure that UCNPs are safe designed. In this study, we used commercially available NaYF4: Er/Yb UCNPs to study their stability in lysosomes and simulated lysosomal fluid. We demonstrate that phosphate complexation leads to REPO4 deposition on the particle surfaces and morphological transformation. This leads to a decline in upconversion fluorescence efficiency as well as inducing pro-inflammatory effects at cellular level and in the intact lung. In order to preserve the imaging properties of the UCNPs as well as improve their safety, we experimented with a series of phosphonate chemical moieties to passivate particle surfaces through the strong coordination of the organophosphates with RE atoms. Particle screening and physicochemical characterization revealed that ethylenediaminetetra methylenephosphonic acid (EDTMP) surface coating provides the most stable UCNPs, which maintain their imaging intensity and do not induce pro-inflammatory effects in vitro and in vivo. In summary, phosphonate coating presents a safer design method that preserves and improves the bio-imaging properties of UCNPs, thereby enhancing their biological use. PMID:25727446

  5. Phosphonate Analogs of 2-Oxoglutarate Perturb Metabolism and Gene Expression in Illuminated Arabidopsis Leaves

    PubMed Central

    Araújo, Wagner L.; Tohge, Takayuki; Nunes-Nesi, Adriano; Daloso, Danilo M.; Nimick, Mhairi; Krahnert, Ina; Bunik, Victoria I.; Moorhead, Greg B. G.; Fernie, Alisdair R.

    2012-01-01

    Although the role of the 2-oxoglutarate dehydrogenase complex (2-OGDHC) has previously been demonstrated in plant heterotrophic tissues its role in photosynthetically active tissues remains poorly understood. By using a combination of metabolite and transcript profiles we here investigated the function of 2-OGDHC in leaves of Arabidopsis thaliana via use of specific phosphonate inhibitors of the enzyme. Incubation of leaf disks with the inhibitors revealed that they produced the anticipated effects on the in situ enzyme activity. In vitro experiments revealed that succinyl phosphonate (SP) and a carboxy ethyl ester of SP are slow-binding inhibitors of the 2-OGDHC. Our results indicate that the reduced respiration rates are associated with changes in the regulation of metabolic and signaling pathways leading to an imbalance in carbon-nitrogen metabolism and cell homeostasis. The inducible alteration of primary metabolism was associated with altered expression of genes belonging to networks of amino acids, plant respiration, and sugar metabolism. In addition, by using isothermal titration calorimetry we excluded the possibility that the changes in gene expression resulted from an effect on 2-oxoglutarate (2OG) binding to the carbon/ATP sensing protein PII. We also demonstrated that the 2OG degradation by the 2-oxoglutarate dehydrogenase strongly influences the distribution of intermediates of the tricarboxylic acid (TCA) cycle and the GABA shunt. Our results indicate that the TCA cycle activity is clearly working in a non-cyclic manner upon 2-OGDHC inhibition during the light period. PMID:22876250

  6. Development of an extractive spectrophotometric method for estimation of uranium in ore leach solutions using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) mixture as extractant and 2-(5-bromo-2-pyridylozo)-5-diethyl aminophenol (Br-PADAP) as chromophore

    NASA Astrophysics Data System (ADS)

    Biswas, Sujoy; Pathak, P. N.; Roy, S. B.

    2012-06-01

    An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (λmax) for UO22+-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ɛ: 36,750 ± 240 L mol-1 cm-1). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to >24 h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO22+-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is <2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ±2%. This method can be used to determine 2.5-250 μg mL-1 uranium in ore leach solutions with high accuracy and precision.

  7. Paclitaxel-loaded phosphonated calixarene nanovesicles as a modular drug delivery platform

    PubMed Central

    Mo, Jingxin; Eggers, Paul K.; Yuan, Zhi-xiang; Raston, Colin L.; Lim, Lee Yong

    2016-01-01

    A modular p-phosphonated calix[4]arene vesicle (PCV) loaded with paclitaxel (PTX) and conjugated with folic acid as a cancer targeting ligand has been prepared using a thin film-sonication method. It has a pH-responsive capacity to trigger the release of the encapsulated PTX payload under mildly acidic conditions. PTX-loaded PCV conjugated with alkyne-modified PEG-folic acid ligands prepared via click ligation (fP-PCVPTX) has enhanced potency against folate receptor (FR)-positive SKOV-3 ovarian tumour cells over FR-negative A549 lung tumour cells. Moreover, fP-PCVPTX is also four times more potent than the non-targeting PCVPTX platform towards SKOV-3 cells. Overall, as a delivery platform the PCVs have the potential to enhance efficacy of anticancer drugs by targeting a chemotherapeutic payload specifically to tumours and triggering the release of the encapsulated drug in the vicinity of cancer cells. PMID:27009430

  8. Phosphonic analogues of tyrosine and 3,4-dihydroxyphenylalanine (dopa) influence mushroom tyrosinase activity.

    PubMed Central

    Lejczak, B; Kafarski, P; Makowiecka, E

    1987-01-01

    A series of phosphonic analogues of tyrosine and 3,4-dihydroxyphenylalanine (dopa) were synthesized in order to study their interaction with mushroom tyrosinase. 1-Amino-2-(3,4-dihydroxyphenyl)ethylphosphonic acid and 1-amino-2-(3,4-dimethoxyphenyl)ethylphosphonic acid turned out to be substrates for mushroom tyrosinase with Km values of 3.3 mM and 9.3 mM respectively. Shortening of the alkyl chain by one methylene group gave amino-(3,4-dihydroxyphenyl)methylphosphonic acid, one of the most powerful known inhibitors of this enzyme. This compound, racemic as well as in its optically active forms, exerts a mixed type of inhibition with an affinity for the enzyme one order of magnitude greater than that of the natural substrate. PMID:3109385

  9. XPS investigation of DNA binding to zirconium-phosphonate surfaces.

    PubMed

    Lane, Sarah M; Monot, Julien; Petit, Marc; Bujoli, Bruno; Talham, Daniel R

    2007-07-01

    The surface coverage of phosphorylated oligonucleotides immobilized on a zirconium-phosphonate surface was analyzed using X-ray photoelectron spectroscopy (XPS). By quantifying the intensity of the N 1s signal originating from the oligonucleotide and the Zr 3d peak from the metal-phosphonate surface, the surface coverage of the oligonucleotide could be calculated with a modified substrate-overlayer model. We found relatively low surface coverages indicating that once covalently bound via the terminal phosphate the polymer chain further physisorbs to the surface limiting the adsorption of additional molecules. PMID:17275268

  10. Amino and Acetamide Functional Group Effects on the Ionization and Fragmentation of Sugar Chains in Positive-Ion Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Yamagaki, Tohru; Sugahara, Kohtaro; Watanabe, Takehiro

    2014-01-01

    To elucidate the influence of amino (-NH2) and acetamide (-NHCOCH3, -NAc) groups in sugar chains on their ionization and fragmentation, cycloamyloses (cyclodextrins, CyDs) and lacto-oligosaccharide are analyzed by MALDI TOF/TOF and ESI Q-TOF mass spectrometry. CyD derivatives substituted by amino or acetamide groups are ideal analytes to extract the function group effects, which are amino-CyD with one hexosamine (HexNH2) and acetamide-CyD with one N-acetyl hexosamine (HexNAc). Interestingly, the relative ion intensities and isotope-like patterns in their product ion spectra depend on the functional groups and ion forms of sugar chains. Consequently, the results indicate that a proton (H+) localizes on the amino group of the amino sugar, and that the proton (H+) induces their fragmentation. Sodium cation (Na+) attachment is independent from amino group and exerts no influence on their fragmentation patterns in amino group except for mono- and disaccharide fragment ions because there is the possibility of the reducing end effect. In contrast, a sodium cation localizes much more frequently on the acetamide group in acetamide-CyDs because the chemical species with HexNAc are stable. Thus, their ions with HexNAc are abundant. These results are consistent with the fragmentation of lacto-neo- N-tetraose and maltotetraose, suggesting that a sodium cation generally localizes much more frequently on the acetamide group in sugar chains.

  11. Anticancer, Anti-Inflammatory, and Analgesic Activities of Synthesized 2-(Substituted phenoxy) Acetamide Derivatives

    PubMed Central

    Pal, Dilipkumar; Hegde, Rahul Rama; Hashim, Syed Riaz

    2014-01-01

    The aphorism was to develop new chemical entities as potential anticancer, anti-inflammatory, and analgesic agents. The Leuckart synthetic pathway was utilized in development of novel series of 2-(substituted phenoxy)-N-(1-phenylethyl)acetamide derivatives. The compounds containing 1-phenylethylamine as basic moiety attached to substituted phenols were assessed for their anticancer activity against MCF-7 (breast cancer), SK-N-SH (neuroblastoma), anti-inflammatory activity, and analgesic activity. These investigations revealed that synthesized products 3a–j with halogens on the aromatic ring favors as the anticancer and anti-inflammatory activity. Among all, compound 3c N-(1-(4-chlorophenyl)ethyl)-2-(4-nitrophenoxy)acetamide exhibited anticancer, anti-inflammatory, and analgesic activities. In conclusion, 3c may have potential to be developed into a therapeutic agent. PMID:25197642

  12. Anticancer, anti-inflammatory, and analgesic activities of synthesized 2-(substituted phenoxy) acetamide derivatives.

    PubMed

    Rani, Priyanka; Pal, Dilipkumar; Hegde, Rahul Rama; Hashim, Syed Riaz

    2014-01-01

    The aphorism was to develop new chemical entities as potential anticancer, anti-inflammatory, and analgesic agents. The Leuckart synthetic pathway was utilized in development of novel series of 2-(substituted phenoxy)-N-(1-phenylethyl)acetamide derivatives. The compounds containing 1-phenylethylamine as basic moiety attached to substituted phenols were assessed for their anticancer activity against MCF-7 (breast cancer), SK-N-SH (neuroblastoma), anti-inflammatory activity, and analgesic activity. These investigations revealed that synthesized products 3a-j with halogens on the aromatic ring favors as the anticancer and anti-inflammatory activity. Among all, compound 3c N-(1-(4-chlorophenyl)ethyl)-2-(4-nitrophenoxy)acetamide exhibited anticancer, anti-inflammatory, and analgesic activities. In conclusion, 3c may have potential to be developed into a therapeutic agent. PMID:25197642

  13. Acetylphosphonate as a Surrogate of Acetate or Acetamide in Organocatalyzed Enantioselective Aldol Reactions

    PubMed Central

    Guang, Jie; Guo, Qunsheng

    2012-01-01

    Highly enantioselective aldol reactions of acetylphosphonates and activated carbonyl compounds was realized with cinchona alkaloid derived catalysts, in which the acetylphosphonate was directly used as an enolate precursor for the first time. The aldol product obtained was converted in situ to its corresponding ester or amide through methanolysis or aminolysis. The overall process may be viewed as formal highly enantioselective acetate or acetamide aldol reactions, which are very difficult to achieve directly with organocatalytic methods. PMID:22650245

  14. Design, synthesis and evaluation of benzofuran-acetamide scaffold as potential anticonvulsant agent.

    PubMed

    Shakya, Ashok K; Kamal, Mehnaz; Balaramnavar, Vishal M; Bardaweel, Sanna K; Naik, Rajashri R; Saxena, Anil K; Siddiqui, H H

    2016-09-01

    A series of N-(2-(benzoyl/4-chlorobenzoyl)-benzofuran- 3-yl)-2-(substituted)-acetamide derivatives (4a-l, 5a-l) was synthesized in good yield. All synthesized compounds were in agreement with elemental and spectral data. The anticonvulsant activity of all synthesized compounds was assessed against the maximal electroshock induced seizures (MES) model in mice. Neurotoxicity was evaluated using the rotarod method. The majority of compounds exhibited anticonvulsant activity at a dose of 30 mg kg-1 body mass during 0.5-4 h, indicating their ability to prevent seizure spread at low doses. Relative to phenytoin, [N-(2-(4-chlorobenzoyl)benzofuran-3-yl)-2-(cyclohexyl( methyl) amino)-acetamide] (5i) and [N-(2-(4-chlorobenzoyl)benzofuran-3-yl)-2-(4-methylpiperidin-1- yl)-acetamide] (5c) demonstrated comparable relative anticonvulsant potency of 0.74 and 0.72, respectively, whereas [(N-(2-(4-chlorobenzoyl)benzofuran-3-yl)-2-(4-(furan-2-carbonyl)-piperazin-1-yl)-acetamide] (5f) exhibited the lowest relative potency of 0.16. The ALD50 of tested compounds ranged from 1.604 to 1.675 mmol kg-1 body mass. The ED50 of synthesized compounds ranged from 0.055 to 0.259 mmol kg-1 (~23.4 to 127.6 mg kg-1) body mass. The pharmacophore mapping of the examined compounds on standard drugs (phenobarbital, phenytoin, ralitolin and carbamazepine) strongly suggests that these compounds may exert their anticonvulsant activity via the same established mechanism as that of known drugs. PMID:27383885

  15. Formation and decomplexation kinetics of copper(ii) complexes with cyclen derivatives having mixed carboxylate and phosphonate pendant arms.

    PubMed

    Ševčík, R; Vaněk, J; Michalicová, R; Lubal, P; Hermann, P; Santos, I C; Santos, I; Campello, M P C

    2016-08-01

    The kinetic properties of Cu(ii) complexes of H4dota and its analogues with one (H5do3ap), two in the 1,7-position (trans-H6do2a2p), three (H7doa3p) and four (H8dotp) phosphonic acid pendant arms were investigated. The formation of a Cu(ii) complex with H4dota, trans-H6do2a2p and H8dotp at a slightly acidic pH is faster for the phosphonic acid derivatives than for H4dota, but with no simple dependence on the number of -CH2PO3H2 substituents (trans-H6do2a2p > H8dotp > H4dota; pH 4-6). Relative differences in the reactivity among the differently protonated species (HnL(x-)) of the same ligand are successively decreased with the more phosphonic acid groups in the ligand. The faster complexation is probably caused by the higher ability of phosphonates to bind the metal ion and/or to assist in the transfer of protons from the ring amine groups to the bulk water. The acid-assisted decomplexation kinetics of the complexes was followed in highly acidic solutions ([H(+)] = 0.01-5 M) and at different temperatures (15-70 °C) to determine the activation parameters of the reaction. The kinetic inertness of the Cu(ii) complexes follows the order: H4dota > H5do3ap > trans-H6do2a2p > H7doa3p > H8dotp. To obtain information on the influence of additional pendant arms, analogous data were obtained for trans-H2do2a. The ligand is less reactive than H4dota, but the kinetic inertness of its Cu(ii) complex is similar to that of the H4dota complex. As it was considered that the published thermodynamics data on the Cu(ii)-H8dotp system are probably incorrect, the system was re-investigated. It showed a very high stability for the [Cu(dotp)](6-) species and the easy formation of several Cu2L species in the presence of an excess of the metal ion. Also, the structure of the (H6doa3p)(-) anion in the solid state was determined. These experimental data demonstrate that the substitution of acetic acid pendant arms by methylphosphonic acid ones in H4dota-like ligands increases the rate of

  16. Efficient functionalization of magnetite nanoparticles with phosphonate using a one-step continuous hydrothermal process.

    PubMed

    Thomas, Guillaume; Demoisson, Frédéric; Boudon, Julien; Millot, Nadine

    2016-06-28

    For the first time, phosphonate-functionalized magnetite nanoparticles (Fe3O4 NPs) were synthesized using a one-step continuous hydrothermal process. The NP surface was modified using a hydrophilic organic molecule, namely 6-phosphonohexanoic acid (PHA). NPs were fully characterized (TEM, XRD, DLS, ζ-potential, TGA, FTIR, XPS and specific surface area measurements) in order to investigate PHA effect on size, oxidation state, anchoring and colloidal stability. PHA reduced the crystallite size and size distribution and improved greatly colloidal stability when compared with bare Fe3O4 NPs. Moreover, PHA was grafted on the NP surface according to three different conformations: as mononuclear monodendates, as binuclear bidentates or as lying-down complexes. This report is very promising regarding the stabilization and functionalization of Fe3O4 NPs by phosphonate molecules under continuous hydrothermal conditions. The post-grafting of polymers such as polyethylene glycol can be considered owing to the presence of free carboxyl groups (-COOH) on the surface of Fe3O4 NPs. PMID:27295502

  17. Use of bifunctional phosphonates for the preparation of heterobimetallic 5f-3d systems.

    PubMed

    Alsobrook, Andrea N; Zhan, Wei; Albrecht-Schmitt, Thomas E

    2008-06-16

    The hydrothermal reaction of phosphonoacetic acid (H2PO3CH2C(O)OH, PAA) with UO3 and Cu(C2H3O2)2 .H2O results in the formation of the crystalline heterobimetallic uranium(VI)/copper(II) phosphonates UO2Cu(PO3CH2CO2)(OH)(H2O)2 ( UCuPAA-1), (UO2) 2Cu(PO3CH2CO2)2(H2O)3 (UCuPAA-2), and [H3O][(UO2) 2Cu2(PO3CH2CO2)3(H2O)2 ( UCuPAA-3). The addition of sodium hydroxide to the aforementioned reactions results in the formation of Na[UO2(PO3CH2CO2)].2H2O (NaUPAA-1). These compounds display 1D (UCuPAA-1), 2D (UCuPAA-2, NaUPAA-1), and 3D (UCuPAA-3) architectures wherein the phosphonate portion of the ligand primarily coordinates the uranium(VI) centers; whereas the carboxylate moiety preferentially, but not exclusively, binds to the copper(II) ions. Fluorescence measurements on all four compounds demonstrate that the presence of copper(II) mostly quenches the emission from the uranyl moieties. PMID:18494466

  18. Flame retardant properties of triazine phosphonates derivative with cotton fabric

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The flame retardant behavior of a cotton fabric treated with phosphorus-nitrogen containing triazine compound was evaluated. It was found that cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) is an excellent starting material for the preparation of phosphonates flame retardants that interacts wel...

  19. Transport of europium through supported liquid membrane containing dihexyl-N,N-diethyl-carbamoyl-methyl-phosphonate

    SciTech Connect

    Nakamura, Shigeto; Akiba, Kenichi )

    1989-12-01

    The transport of europium has been studied through a supported liquid membrane (SLM) impregnated with dihexyl-N,N-diethyl-carbamoyl-methyl-phosphonate (CMP). Europium was effectively extracted from the perchlorate solution into SLM, but was insufficiently stripped to a dilute acid solution. The addition of 1-decanol improved the stripping process, and quantitative transport of europium was achieved. By the combination of two SLM systems consisting of diisodecylphosphoric acid and CMP, europium was transported from the feed solution (0.1 M HNO{sub 3}) through the intermediate solution (1 M HClO{sub 4} + 4 M NaClO{sub 4}) to the product solution (0.1 M HNO{sub 3}) and effectively concentrated by a factor of about 20.

  20. Synthesis, crystal structure and DFT studies of N-(4-acetyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide

    SciTech Connect

    Gautam, P.; Gautam, D.; Chaudhary, R. P.

    2013-12-15

    The title compound N-(4-acetyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide (III) was obtained from the reaction of 2-(propan-2-ylidene)hydrazinecarbothioamide (II) with acetic anhydride instead of formation of the desired thiosemcarbazide derivative of Meldrum acid. The structures of II and III were established by elemental analysis, IR, NMR, Mass and X-ray crystallographic studies. II crystallizes in triclinic system, sp. gr. P-bar1 Z = 2; III crystallizes in the monoclinic system, sp. gr. P2{sub 1}/c, Z = 8. Density functional theory (DFT) calculations have been carried out for III. {sup 1}H and {sup 13}C NMR of III has been calculated and correlated with experimental results.

  1. Structure of the Escherichia coli Phosphonate Binding Protein PhnD and Rationally Optimized Phosphonate Biosensors

    SciTech Connect

    Alicea, Ismael; Marvin, Jonathan S.; Miklos, Aleksandr E.; Ellington, Andrew D.; Looger, Loren L.; Schreiter, Eric R.

    2012-09-17

    The phnD gene of Escherichia coli encodes the periplasmic binding protein of the phosphonate (Pn) uptake and utilization pathway. We have crystallized and determined structures of E. coli PhnD (EcPhnD) in the absence of ligand and in complex with the environmentally abundant 2-aminoethylphosphonate (2AEP). Similar to other bacterial periplasmic binding proteins, 2AEP binds near the center of mass of EcPhnD in a cleft formed between two lobes. Comparison of the open, unliganded structure with the closed 2AEP-bound structure shows that the two lobes pivot around a hinge by {approx}70{sup o} between the two states. Extensive hydrogen bonding and electrostatic interactions stabilize 2AEP, which binds to EcPhnD with low nanomolar affinity. These structures provide insight into Pn uptake by bacteria and facilitated the rational design of high signal-to-noise Pn biosensors based on both coupled small-molecule dyes and autocatalytic fluorescent proteins.

  2. Direct phosphonation of quinoxalin-2(1H)-ones under transition-metal-free conditions.

    PubMed

    Gao, Ming; Li, Yi; Xie, Lijuan; Chauvin, Remi; Cui, Xiuling

    2016-02-01

    A direct C-H bond phosphonation of quinoxalin-2(1H)-ones with H-phosphonates, H-phosphinates or H-phosphine oxides has been developed. A wide variety of heteroaryl phosphonates were obtained in up to 92% yield for 20 examples under transition-metal-free conditions. This protocol tolerates a broad scope of substrates and features practicality, high efficiency, environmental friendliness and atom economy. PMID:26779573

  3. Rhodium-catalyzed asymmetric hydrogenation of unprotected β-enamine phosphonates.

    PubMed

    Zhou, Ming; Xue, Zejian; Cao, Min; Dong, Xiu-Qin; Zhang, Xumu

    2016-05-18

    We have successfully developed a strategy for the first time for the enantioselective Rh-TaniaPhos catalyzed asymmetric hydrogenation of unprotected β-enamine phosphonates to free β-amino phosphonates directly with good enantioselectivities (80%-86% ee) and high conversions (>99% conversion). The resulting chiral free β-amino phosphonates and their derivatives are important intermediates in biochemistry and pharmaceuticals. PMID:27137841

  4. Layered zirconium phosphonate with inorganic–organic hybrid structure: Preparation and its assembly with DNA

    SciTech Connect

    Liu, Li-Min; Lu, Guo-Yuan; Jiang, Li-Ping; Zhu, Jun-Jie

    2014-07-01

    An aminoethoxy-functionalized zirconium phosphonate (Zr(O{sub 3}POCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}·3H{sub 2}O), abbreviated as ZrRP (R=OCH{sub 2}CH{sub 2}NH{sub 2}), with layered structure has been synthesized. This layered compound possesses the characteristic of inorganic–organic hybrid, due to the covalently linked aminoethoxy in the host layer. The anion exchanged property of this zirconium phosphonate is suitable for the direct intercalation of negatively charged DNA, which is different from these reported zirconium phosphates or zirconium phosphonates. As a precursor, this prepared zirconium phosphonate was utilized to fabricate a novel DNA/ZrRP binary hybrid via a delamination-reassembly procedure. The release behavior of DNA from the DNA/ZrRP composite was investigated at different medium pH, because the combination between zirconium phosphonate sheets and DNA was pH-dependent sensitively. Moreover, the helical conformation of DNA was almost retained after the intercalation and release process. These properties of the DNA/ZrRP composite suggested the potential application of layered zirconium phosphonate as a non-viral vector in gene delivery. - Graphical abstract: The intercalation of DNA into zirconium phosphonate and the release of DNA from the interlayer of zirconium phosphonate. - Highlights: ●A layered aminoethoxy-functionalized zirconium phosphonate has been synthesized. ●DNA was intercalated directly into the prepared zirconium phosphonate. ●A novel zirconium phosphonate/DNA binary hybrid was fabricated. ●DNA can be reversibly released from the interlayer of zirconium phosphonate. ●The intercalation/release processes do not induce the denaturalization of DNA.

  5. Synthesis of lesquerella a-hydroxy phosphonates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydroxy fatty acids (HFAs) have found a number of uses in today’s market, with uses ranging from industrial materials to pharmaceuticals. Castor oil, which is obtained from castor seeds, has served as a source of a versatile HFA; its principle component, ricinoleic acid, can be isolated from castor ...

  6. Acyclic nucleoside phosphonates with 5-azacytosine base moiety substituted in C-6 position.

    PubMed

    Krecmerová, Marcela; Masojídková, Milena; Holý, Antonín

    2010-01-01

    Two methods for preparation of 6-substituted derivatives of anti DNA-viral agent 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-5-azacytosine (HPMP-5-azaC) were developed: (1) ammonia mediated ring-opening reaction of diisopropyl esters of HPMP-5-azaC (4) to carbamoylguanidine derivatives followed by ring-closure reaction with orthoesters and (2) condensation reaction of 6-substituted 5-azacytosines with diisopropyl (1S)-[2-hydroxy-1-tosyloxymethyl)ethoxy]methylphosphonate (15). Deprotection of diisopropyl esters to free phosphonic acids was performed with bromotrimethylsilane in acetonitrile followed by hydrolysis. In contrast to parent compound HPMP-5-azaC, a substantial decrease of antiviral activity in case of 6-substituted analogues occurred. Surprisingly, N-3 isomer of 6-methyl-HPMP-5-azaC in the form of isopropyl ester revealed activity against RNA viruses (Sindbis virus). PMID:19914075

  7. Enhanced cell affinity of poly( L-lactide) film by immobilizing phosphonized chitosan

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Zhou, Chang-ren; Zeng, Qing-hui; Yang, Ju-lin; Han, Feng-xian; Tian, Jin-huan

    2008-11-01

    Graft polymerization of acrylic acid (AA) onto poly( L-lactide) (PLLA) film by UV irradiation was carried out to develop surfaces for N-methylene phosphonic chitosan (NMPC) immobilization. The properties of modified films were discussed by colorimetric method, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), contact angles, atomic force microscopy (AFM) and osteoblast incubation. The results showed that AA solution concentration and irradiation time had effect on the graft carboxyl densities. Comparing the ATR-FTIR images, two new peaks at 1561 cm -1 and 1632 cm -1 proved that NMPC was immobilized on the film surface successfully. The water contact-angles were decreased from 90 ± 5° to 37 ± 5° after modification. The AFM images indicated that the surface of the combined film was rougher than that of untreated film. The grafted film provided an excellent substrate for the growth of osteoblast.

  8. Peptide bond formation through gas-phase reactions in the interstellar medium: formamide and acetamide as prototypes

    SciTech Connect

    Redondo, Pilar; Barrientos, Carmen; Largo, Antonio

    2014-09-20

    A theoretical study of the reactions of NH{sub 4}{sup +} with formaldehyde and CH{sub 5}{sup +} with formamide is carried out. The viability of these gas-phase ion-molecule reactions as possible sources of formamide and acetamide under the conditions of interstellar medium is evaluated. We report a theoretical estimation of the reaction enthalpies and an analysis of their potential energy surfaces. Formation of protonated formamide from the reaction between ammonium cation and formaldehyde is an exothermic process, but all the channels located on the potential energy surface leading to this product present net activation energies. For the reaction between methanium and formamide, different products are possible from a thermodynamic point of view. An analysis of its potential energy surface showed that formation of protonated acetamide and amino acetaldehyde takes place through barrier-free paths. Therefore, this reaction could be a feasible source of acetamide and amino acetaldehyde in space.

  9. Acetamide derivatives with antioxidant activity and potential anti-inflammatory activity.

    PubMed

    Autore, Giuseppina; Caruso, Anna; Marzocco, Stefania; Nicolaus, Barbara; Palladino, Chiara; Pinto, Aldo; Popolo, Ada; Sinicropi, Maria S; Tommonaro, Giuseppina; Saturnino, Carmela

    2010-03-01

    This study reports the synthesis and antioxidant activity of some new acetamide derivatives. The compounds' structures were elucidated by NMR analysis and their melting points were measured. The in vitro antioxidant activity of these compounds was tested by evaluating the amount of scavenged ABTS radical and estimating ROS and NO production in tBOH- or LPS-stimulated J774.A1 macrophages. All compounds were tested for their effect on cell viability by an MTT assay and by a Brine Shrimp Test. PMID:20336030

  10. Copper(I)-Catalyzed Asymmetric Dearomatization of Indole Acetamides with 3-Indolylphenyliodonium Salts.

    PubMed

    Liu, Chuan; Yi, Ji-Cheng; Liang, Xiao-Wei; Xu, Ren-Qi; Dai, Li-Xin; You, Shu-Li

    2016-07-25

    The rapid and direct asymmetric synthesis of 3-(3a-indolyl)hexahydropyrroloindoline motifs is an extremely important part of the total synthesis of several alkaloid structures. Herein, an intermolecular, asymmetric cascade dearomatization reaction of indole acetamides with 3-indolylphenyliodonium salts has been developed. This protocol provides a straightforward access to 3-(3a-indolyl)hexahydropyrroloindolines bearing an all-carbon quaternary stereocenter at the C3 position of the indoline ring with high enantioselectivities. The utility of the protocol has been demonstrated by the formal asymmetric synthesis of folicanthine. PMID:27171171

  11. Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates.

    PubMed

    Haji, Mohammad

    2016-01-01

    Multicomponent reactions (MCRs) are one of the most important processes for the preparation of highly functionalized organic compounds in modern synthetic chemistry. As shown in this review, they play an important role in organophosphorus chemistry where phosphorus reagents are used as substrates for the synthesis of a wide range of phosphorylated heterocycles. In this article, an overview about multicomponent reactions used for the synthesis of heterocyclic compounds bearing a phosphonate group on the ring is given. PMID:27559377

  12. Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

    PubMed Central

    2016-01-01

    Summary Multicomponent reactions (MCRs) are one of the most important processes for the preparation of highly functionalized organic compounds in modern synthetic chemistry. As shown in this review, they play an important role in organophosphorus chemistry where phosphorus reagents are used as substrates for the synthesis of a wide range of phosphorylated heterocycles. In this article, an overview about multicomponent reactions used for the synthesis of heterocyclic compounds bearing a phosphonate group on the ring is given. PMID:27559377

  13. Synthesis of a Series of γ-Keto Allyl Phosphonates.

    PubMed

    Elleuch, Haitham; Ayadi, Marwa; Bouajila, Jalloul; Rezgui, Farhat

    2016-03-01

    Under solvent-free conditions and at 80 °C, a DMAP- or imidazole-mediated clean and rapid conversion of cyclic Morita-Baylis-Hillman (MBH) acetates into the corresponding γ-keto allyl phosphonates in 70-93% yields is described herein. This allylic nucleophilic substitution works well with primary and secondary acetates bearing, at the β'-position, linear or branched alkyl groups and aryl groups. PMID:26872500

  14. Morphology and Proton Transport in Humidified Phosphonated Peptoid Block Copolymers

    PubMed Central

    2016-01-01

    Polymers that conduct protons in the hydrated state are of crucial importance in a wide variety of clean energy applications such as hydrogen fuel cells and artificial photosynthesis. Phosphonated and sulfonated polymers are known to conduct protons at low water content. In this paper, we report on the synthesis phosphonated peptoid diblock copolymers, poly-N-(2-ethyl)hexylglycine-block-poly-N-phosphonomethylglycine (pNeh-b-pNpm), with volume fractions of pNpm (ϕNpm) values ranging from 0.13 to 0.44 and dispersity (Đ) ≤ 1.0003. The morphologies of the dry block copolypeptoids were determined by transmission electron microscopy and in both the dry and hydrated states by synchrotron small-angle X-ray scattering. Dry samples with ϕNpm > 0.13 exhibited a lamellar morphology. Upon hydration, the lowest molecular weight sample transitioned to a hexagonally packed cylinder morphology, while the others maintained their dry morphologies. Water uptake of all of the ordered samples was 8.1 ± 1.1 water molecules per phosphonate group. In spite of this, the proton conductivity of the ordered pNeh-b-pNpm copolymers ranged from 0.002 to 0.008 S/cm. We demonstrate that proton conductivity is maximized in high molecular weight, symmetric pNeh-b-pNpm copolymers. PMID:27134312

  15. Phosphonate biosynthesis and catabolism: a treasure trove of unusual enzymology.

    PubMed

    Peck, Spencer C; van der Donk, Wilfred A

    2013-08-01

    Natural product biosynthesis has proven a fertile ground for the discovery of novel chemistry. Herein we review the progress made in elucidating the biosynthetic pathways of phosphonate and phosphinate natural products such as the antibacterial compounds dehydrophos and fosfomycin, the herbicidal phosphinothricin-containing peptides, and the antimalarial compound FR-900098. In each case, investigation of the pathway has yielded unusual, and often unprecedented, biochemistry. Likewise, recent investigations have uncovered novel ways to cleave the CP bond to yield phosphate under phosphorus starvation conditions. These include the discovery of novel oxidative cleavage of the CP bond catalyzed by PhnY and PhnZ as well as phosphonohydrolases that liberate phosphate from phosphonoacetate. Perhaps the crown jewel of phosphonate catabolism has been the recent resolution of the longstanding problem of the C-P lyase responsible for reductively cleaving the CP bond of a number of different phosphonates to release phosphate. Taken together, the strides made on both metabolic and catabolic fronts illustrate an array of fascinating biochemistry. PMID:23870698

  16. Phosphonate analogues of carboxypeptidase A substrates are potent transition-state analogue inhibitors.

    PubMed

    Hanson, J E; Kaplan, A P; Bartlett, P A

    1989-07-25

    Analogues of tri- and tetrapeptide substrates of carboxypeptidase A in which the scissile peptide linkage is replaced with a phosphonate moiety (-PO2--O-) were synthesized and evaluated as inhibitors of the enzyme. The inhibitors terminated with either L-lactate or L-phenyllactate [designated (O) Ala and (O) Phe, respectively] in the P1' position. Transition-state analogy was shown for a series of 14 tri- and tetrapeptide derivatives containing the structure RCO-AlaP-(O)Ala [RCO-AP(O)A, AP indicates the phosphonic acid analogue of alanine] by the correlation of the Ki values for the inhibitors and the Km/kcat values for the corresponding amide substrates. This correlation supports a transition state for the enzymatic reaction that resembles the tetrahedral intermediate formed upon addition of water to the scissile carbonyl group. The inhibitors containing (O) Phe at the P1' position proved to be the most potent reversible inhibitors of carboxypeptidase A reported to date: the dissociation constants of ZAFP(O)F, ZAAP(O)F, and ZFAP(O)F are 4, 3, and 1 pM, respectively. Because of the high affinity of these inhibitors, their dissociation constants could not be determined by steady-state methods. Instead, the course of the association and dissociation processes was monitored for each inhibitor as its equilibrium with the enzyme was established in both the forward and reverse directions. A phosphonamidate analogue, ZAAPF, in which the peptide linkage is replaced with a -PO2-NH- moiety, was prepared and shown to hydrolyze rapidly at neutral pH (t1/2 = 20 min at pH 7.5). This inhibitor is bound an order of magnitude less tightly than the corresponding phosphonate, ZAAP(O)F, a result that contrasts with the 840-fold higher affinity of phosphonamidates for thermolysin [Bartlett, P. A., & Marlowe, C. K. (1987) Science 235, 569-571], a zinc peptidase with a similar arrangement of active-site catalytic residues. PMID:2790000

  17. New water soluble phosphonate and polycarboxylate complexants for enhanced f element separations

    SciTech Connect

    Nash, K.L.; Rickert, P.G.; Lessmann, E.P.; Mendoza, M.D.; Feil, J.F.; Sullivan, J.C.

    1994-08-01

    While lipophilic extractant molecules and ion exchange polymeric materials are clearly essential to efficient separation of metal ions by solvent extraction or ion exchange, the most difficult separations often could not be accomplished without the use of water soluble complexants. This report focuses on recent developments in design, synthesis and characterization of phosphonic acid and polycarboxylic acid ligands for enhanced f element separations. Emphasis is on the basic solution chemistry and crystal structures of complexes of the f elements with selected amino-derivatives of methanediphosphonic acid and with tetrahydrofuran-2,3,4,5-tetracarboxylic acid. The former series of compounds exhibit high affinity for lanthanides and actinides in acidic solutions. The latter ligand exhibits an unusual (and very useful) ``anti-selectivity`` for uranyl ion in a solvent extraction process, which permits efficient separation of uranyl from more radioactive components of nuclear wastes. Most of the observed effects can be explained through examination of the structure of the ligand, and comparison of the spectroscopic and thermodynamic parameters for complexation of various metal ions.

  18. Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group?Determination of acetamide herbicides and their degradation products in water using online solid-phase extraction and liquid chromatography/mass spectrometry

    USGS Publications Warehouse

    Lee, E.A.; Strahan, A.P.

    2003-01-01

    An analytical method for the determination of 6 acetamide herbicides (acetochlor, alachlor, dimethenamid, flufenacet, metolachlor, and propachlor) and 16 of their degradation products in natural water samples using solid-phase extraction and liquid chromatography/mass spectrometry is described in this report. Special consideration was given during the development of the method to prevent the formation of degradation products during the analysis. Filtered water samples were analyzed using octadecylsilane as the solid-phase extraction media on online automated equipment followed by liquid chromatography/mass spectrometry. The method uses only 10 milliliters of sample per injection. Three different water-sample matrices, a reagent-water, a ground-water, and a surface-water sample spiked at 0.10 and 1.0 microgram per liter, were analyzed to determine method performance. Method detection limits ranged from 0.004 to 0.051 microgram per liter for the parent acetamide herbicides and their degradation products. Mean recoveries for the acetamide compounds in the ground- and surface-water samples ranged from 62.3 to 117.4 percent. The secondary amide of acetochlor/metolachlor ethanesulfonic acid (ESA) was recovered at an average rate of 43.5 percent. The mean recoveries for propachlor and propachlor oxanilic acid (OXA) were next lowest, ranging from 62.3 to 95.5 percent. Mean recoveries from reagent-water samples ranged from 90.3 to 118.3 percent for all compounds. Overall the mean of the mean recoveries of all compounds in the three matrices spiked at 0.10 and 1.0 microgram per liter ranged from 89.9 to 100.7 percent, including the secondary amide of acetochlor/metolachlor ESA and the propachlor compounds. The acetamide herbicides and their degradation products are reported in concentrations ranging from 0.05 to 2.0 micrograms per liter. The upper concentration limit is 2.0 micrograms per liter for all compounds without dilution. With the exception of the secondary amide of

  19. Phosphonate removal from discharged circulating cooling water using iron-carbon micro-electrolysis.

    PubMed

    Zhou, Zhen; Qiao, Weimin; Lin, Yangbo; Shen, Xuelian; Hu, Dalong; Zhang, Jianqiao; Jiang, Lu-Man; Wang, Luochun

    2014-01-01

    Phosphonate is a commonly used corrosion and scale inhibitor for a circulating cooling water (CCW) system. Its discharge could cause eutrophication of receiving waters. The iron-carbon (Fe/C) micro-electrolysis technology was used to degrade and remove phosphonate from discharged CCW. The influences of initial pH, Fe/C ratio (FCR) and temperature on phosphonate removal were investigated in a series of batch tests and optimized by response surface methodology. The quadratic model of phosphonate removal was obtained with satisfactory degrees of fitness. The optimum conditions with total phosphorus removal efficiency of 95% were obtained at pH 7.0, FCR of 1.25, and temperature of 45 °C. The phosphonate removal mechanisms were also studied. Phosphonate removal occurred predominantly via two consecutive reactive phases: the degradation of phosphonate complexes (Ca-phosphonate) and the precipitation of Fe/C micro-electrolysis products (PO₄(3-), Ca²⁺ and Fe³⁺). PMID:25098884

  20. Structural variation in cation-assisted assembly of high-nuclearity Mn arsonate and phosphonate wheels.

    PubMed

    Chimamkpam, Theresa O; Clérac, Rodolphe; Mitcov, Dmitri; Twamley, Brendan; Venkatesan, Munuswamy; Schmitt, Wolfgang

    2016-01-28

    Comproportionation reactions between MnCl2 and KMnO4 in the presence of arsonate or phosphonate ligands promote the cation-assisted assembly of high-nuclearity, wheel-shaped or toroidal {Mn8} () and {Mn24} () complexes; the closely corresponding reaction systems provide insights into the complexation behaviour of homologous phosphonate/arsonate ligand species. PMID:26740231

  1. Discovery of GS-9131: Design, synthesis and optimization of amidate prodrugs of the novel nucleoside phosphonate HIV reverse transcriptase (RT) inhibitor GS-9148.

    PubMed

    Mackman, Richard L; Ray, Adrian S; Hui, Hon C; Zhang, Lijun; Birkus, Gabriel; Boojamra, Constantine G; Desai, Manoj C; Douglas, Janet L; Gao, Ying; Grant, Deborah; Laflamme, Genevieve; Lin, Kuei-Ying; Markevitch, David Y; Mishra, Ruchika; McDermott, Martin; Pakdaman, Rowchanak; Petrakovsky, Oleg V; Vela, Jennifer E; Cihlar, Tomas

    2010-05-15

    GS-9148 [(5-(6-amino-purin-9-yl)-4-fluoro-2,5-dihydro-furan-2-yloxymethyl)phosphonic acid] 4 is a novel nucleoside phosphonate HIV-1 reverse transcriptase (RT) inhibitor with a unique resistance profile toward N(t)RTI resistance mutations. To effectively deliver 4 and its active phosphorylated metabolite 15 into target cells, a series of amidate prodrugs were designed as substrates of cathepsin A, an intracellular lysosomal carboxypeptidase highly expressed in peripheral blood mononuclear cells (PBMCs). The ethylalaninyl phosphonamidate prodrug 5 (GS-9131) demonstrated favorable cathepsin A substrate properties, in addition to favorable in vitro intestinal and hepatic stabilities. Following oral dosing (3mg/kg) in Beagle dogs, high levels (>9.0microM) of active metabolite 15 were observed in PBMCs, validating the prodrug design process and leading to the nomination of 5 as a clinical candidate. PMID:20409721

  2. Growth and characterization of new organic nonlinear optical crystal (R)-2-cyano-N-(1-phenylethyl) acetamide

    SciTech Connect

    Hemaraju, B. C.; Gnana Prakash, A. P.; Madhukar, B. S.; Bhadregowda, D. G.

    2014-04-24

    (R)-2-Cyano-N-(1-phenylethyl) acetamide (RCNPA) single crystals were grown by slow evaporation of the aqueous solution at room temperature (300K) using ethanol. The grown crystals were characterized by single crystal X-ray diffraction, powder X-ray diffraction, FTIR, UV-Vis-NIR transmittance, scanning electron microscopy (SEM) and powder second harmonic generation (SHG)

  3. 40 CFR 721.267 - N-[2-[(substituted dinitrophenyl)azo]diallylamino-4- substituted phenyl] acetamide (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false N- diallylamino-4- substituted phenyl] acetamide (generic name). 721.267 Section 721.267 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

  4. 40 CFR 721.267 - N-[2-[(substituted dinitrophenyl)azo]diallylamino-4- substituted phenyl] acetamide (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false N- diallylamino-4- substituted phenyl] acetamide (generic name). 721.267 Section 721.267 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

  5. 40 CFR 721.267 - N-[2-[(substituted dinitrophenyl)azo]diallylamino-4- substituted phenyl] acetamide (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false N- diallylamino-4- substituted phenyl] acetamide (generic name). 721.267 Section 721.267 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

  6. [Synthesis and biological properties of α-thymidine 5'-aryl phosphonates].

    PubMed

    Ivanov, M A; Karpenko, I L; Chernousova, L N; Andreevskaia, S N; Smirnova, T G; Aleksandrova, L A

    2013-01-01

    The interaction of CDI-activated diethyl phosphonoacetate with methyl 4-aminobenzoat or 3,5-difluoromethylphenylamine followed by treatment with Me3SiBr in DMF led to N-aryl aminocarbonylmethyl phosphonates and their ethyl esters. Their coupling with 3'-acetyl-α-thymidine followed by removal of the acetyl groups gave (α-D-thymidine-5'-il) N-[4-(methoxycarbonyl-, aminocarbonyl- and carboxy)phenyl]-aminocarbonylmethyl phosphonates, (α-D-thymidine-5'-il)-[3,5-bis(trifluoromethyl)phenylaminocarbonyl]methyl phosphonate and their ethyl esters. The phosphonates were stable in different conditions, low cytotoxic (in Vero and K562 cells) and were able to penetrate into K562 cells. The only ethyl ester of (α-D-thymidine-5'-il) N-[4-(methoxycarbonyl)phenyl]-aminocarbonylmethyl phosphonate in high concentration (200 μg/mL) inhibited in vitro the growth of laboratory sensitive strain of Mycobacterium tuberculosis H37Rv. PMID:25696933

  7. Phosphonate analogues of cyclopropavir phosphates and their E-isomers. Synthesis and antiviral activity.

    PubMed

    Mhaske, Santosh B; Ksebati, Bashar; Prichard, Mark N; Drach, John C; Zemlicka, Jiri

    2009-06-01

    Z- and E-Phosphonate analogues 12 and 13 derived from cyclopropavir and the corresponding cyclic phosphonates 14 and 15 were synthesized and their antiviral activity was investigated. The 2,2-bis(hydroxymethylmethylenecyclopropane acetate (17) was transformed to tetrahydropyranyl acetate 18. Deacetylation gave intermediate 19 which was converted to bromide 20. Alkylation with diisopropyl methylphosphonate afforded after protecting group exchange (21 to 22) acetylated phosphonate intermediate 22. Addition of bromine gave the dibromo derivative 16 which was used in the alkylation-elimination procedure with 2-amino-6-chloropurine to give Z- and E-isomers 23 and 24. Hydrolytic dechlorination coupled with removal of all protecting groups gave the guanine phosphonates 12 and 13. Cyclization afforded the cyclic phosphonates 14 and 15. Z-Phosphonate 12 was a potent and non-cytotoxic inhibitor of human and murine cytomegalovirus (HCMV and MCMV) with EC(50) 2.2-2.7 and 0.13 microM, respectively. It was also an effective agent against Epstein-Barr virus (EBV, EC(50) 3.1 microM). The cyclic phosphonate 14 inhibited HCMV (EC(50) 2.4-11.5 microM) and MCMV (EC(50) 0.4 microM) but it was ineffective against EBV. Both phosphonates 12 and 14 were as active against two HCMV Towne strains with mutations in UL97 as they were against wild-type HCMV thereby circumventing resistance due to such mutations. Z-Phosphonate 12 was a moderate inhibitor of replication of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) but it was a potent agent against varicella zoster virus (VZV, EC(50) 2.9 microM). The cyclic phosphonate 14 lacked significant potency against these viruses. E-isomers 13 and 15 were devoid of antiviral activity. PMID:19410465

  8. Phosphonate Analogues of Cyclopropavir Phosphates and Their E-isomers. Synthesis and Antiviral Activity

    PubMed Central

    Mhaske, Santosh B.; Ksebati, Bashar; Prichard, Mark N.; Drach, John C.; Zemlicka, Jiri

    2009-01-01

    Z- and E-phosphonate analogues 12 and 13 derived from cyclopropavir and the corresponding cyclic phosphonates 14 and 15 were synthesized and their antiviral activity was investigated. The 2,2-bis(hydroxymethylmethylenecyclopropane acetate (17) was transformed to tetrahydropyranyl acetate 18. Deacetylation gave intermediate 19 which was converted to bromide 20. Alkylation with diisopropyl methylphosphonate afforded after protecting group exchange (21 to 22) acetylated phosphonate intermediate 22. Addition of bromine gave the dibromo derivative 16 which was used in the alkylation-elimination procedure with 2-amino-6-chloropurine to give Z- and E-isomers 23 and 24. Hydrolytic dechlorination coupled with removal of all protecting groups gave the guanine phosphonates 12 and 13. Cyclization afforded the cyclic phosphonates 14 and 15. Z-Phosphonate 12 was a potent and non-cytotoxic inhibitor of human and murine cytomegalovirus (HCMV and MCMV) with EC50 2.2-2.7 and 0.13 μM, respectively. It was also an effective agent against Epstein-Barr virus (EBV, EC50 3.1 μM). The cyclic phosphonate 14 inhibited HCMV (EC50 2.4-11.5 μM) and MCMV (EC50 0.4 μM) but it was ineffective against EBV. Both phosphonates 12 and 14 were as active against two HCMV Towne strains with mutations in UL97 as they were against wild-type HCMV thereby circumventing resistance due to such mutations. Z-Phosphonate 12 was a moderate inhibitor of replication of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) but it was a potent agent against varicella zoster virus (VZV, EC50 2.9 μM). The cyclic phosphonate 14 lacked significant potency against these viruses. E-isomers 13 and 15 were devoid of antiviral activity. PMID:19410465

  9. Site-selective chemical modification of chymotrypsin using peptidyl derivatives bearing optically active diphenyl 1-amino-2-phenylethylphosphonate: Stereochemical effect of the diphenyl phosphonate moiety.

    PubMed

    Ono, Shin; Nakai, Takahiko; Kuroda, Hirofumi; Miyatake, Ryuta; Horino, Yoshikazu; Abe, Hitoshi; Umezaki, Masahito; Oyama, Hiroshi

    2016-11-01

    Diphenyl (α-aminoalkyl)phosphonates act as mechanism-based inhibitors against serine proteases by forming a covalent bond with the hydroxy group of the active center Ser residue. Because the covalent bond was found to be broken and replaced by 2-pyridinaldoxime methiodide (2PAM), we employed a peptidyl derivative bearing diphenyl 1-amino-2-phenylethylphosphonate moiety (Phe(p) (OPh)2 ) to target the active site of chymotrypsin and to selectively anchor to Lys175 in the vicinity of the active site. Previously, it was reported that the configuration of the α-carbon of phosphorus in diphenyl (α-aminoalkyl)phosphonates affects the inactivation reaction of serine proteases, i.e., the (R)-enantiomeric diphenyl phosphonate is comparable to l-amino acids and it effectively reacts with serine proteases, whereas the (S)-enantiomeric form does not. In this study, we evaluated the stereochemical effect of the phosphonate moiety on the selective chemical modification. Epimeric dipeptidyl derivatives, Ala-(R or S)-Phe(p) (OPh)2 , were prepared by separation with RP-HPLC. A tripeptidyl (R)-epimer (Ala-Ala-(R)-Phe(p) (OPh)2 ) exhibited a more potent inactivation ability against chymotrypsin than the (S)-epimer. The enzyme inactivated by the (R)-epimer was more effectively reactivated with 2PAM than the enzyme inactivated by the (S)-epimer. Finally, N-succinimidyl (NHS) active ester derivatives, NHS-Suc-Ala-Ala- (R or S)-Phe(p) (OPh)2 , were prepared, and we evaluated their action when modifying Lys175 in chymotrypsin. We demonstrated that the epimeric NHS derivative that possessed the diphenyl phosphonate moiety with the (R)-configuration effectively modified Lys175 in chymotrypsin, whereas that with the (S)-configuration did not. These results demonstrate the utility of peptidyl derivatives that bear an optically active diphenyl phosphonate moiety as affinity labeling probes in protein bioconjugation. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 521-530, 2016

  10. The Microwave Spectrum of Monodeuterated Acetamide CH_2DC(=O)NH_2

    NASA Astrophysics Data System (ADS)

    Konov, I. A.; Coudert, L. H.; Gutle, C.; Huet, T. R.; Margulès, L.; Motiyenko, R. A.; Møllendal, H.; Guillemin, J.-C.

    2014-06-01

    Acetamide is an oblate asymmetric top displaying almost free internal rotation of its methyl group. The microwave spectrum of the normal species (CH_3C(=O)NH_2) has already been studied and a value of only 25 wn was retrieved for the height of the potential barrier hindering the internal rotation. No spectroscopic results are available about the monodeutared species with a partially deuterated CH_2D methyl group which will be the subject of the present talk. The effects of deuteration on the hindering potential will be investigated first. They lead to qualitative changes of the hindering potential no longer resembling that of the normal species and displaying several inequivalent minima. A determination of the torsional potential will be attempted through an analysis of the microwave spectrum of the monodeuterated species in which torsion-rotation energies are calculated with the approach developed for monodeuterated methanol, accounting for the torsion-rotation Coriolis coupling and for the dependence of the inertia tensor on the torsional angle. A low temperature spectrum, recorded with the MB-FTMW spectrometer in Lille, has already been analyzed and 14 transitions could be assigned up to J=6. Room temperature spectra have also been recorded in the 7-91 and 150-165 GHz frequency ranges and more than 100 transitions have been assigned up to J=16 for the ground torsional state. In the paper, deuteration effects will be discussed and we hope to assign a sufficient number of microwave transitions in order to obtain the first quantitative information about the hindering potential of monodeuterated acetamide. Ilyushin, Alekseev, Dyubko, Kleiner, and Hougen, J. Molec. Spectrosc. 227 (2004) 115 Lauvergnat, Coudert, Klee, and Smirnov, J. Molec. Spectrosc. 256 (2009) 204 Margulès, Coudert, Møllendal, Guillemin, Huet and Janečková, J. Molec. Spectrosc. 254 (2009) 55 Coudert, Zemouli, Motiyenko, Margulès, and Klee, J. Chem. Phys. 140 (2014) 064307

  11. Adsorption and removal kinetics of phosphonate from water using natural adsorbents.

    PubMed

    Kumar, R Anil; Velayudhan, K T; Ramachandran, V; Bhai, R Susheela; Unnikrishnan, G; Vasu, K

    2010-01-01

    The removal of phosphonate from water was studied using some natural adsorbents. Potassium phosphonate is a fungicide used for the control of Phytophthora capsici, which is prevalent in black pepper (Piper nigrum L.). Batch adsorption kinetic experiments were conducted on the adsorption of phosphonate onto the adsorbents. The concentration of phosphonate was measured on a high-performance liquid chromatograph fitted with a conductivity detector. The percentage removal of phosphonate by powdered laterite stone (PLS) from water was 40.4%, within a residence time of 15 minutes. The mechanisms of the rate of adsorption were analyzed and compared using the pseudo-second-order, Elovich, and intraparticle diffusion models. The experimental data was found to correlate well with the pseudo-second-order kinetic model, indicating adsorption as a chemisorption process. A possible reaction in the phosphonate-PLS system also has been proposed. The PLS can be used as a low-cost natural adsorbent for phosphonate removal from water. PMID:20112539

  12. Phosphonate utilization by the globally important marine diazotroph Trichodesmium.

    PubMed

    Dyhrman, S T; Chappell, P D; Haley, S T; Moffett, J W; Orchard, E D; Waterbury, J B; Webb, E A

    2006-01-01

    The factors that control the growth and nitrogen fixation rates of marine diazotrophs such as Trichodesmium have been intensively studied because of the role that these processes have in the global cycling of carbon and nitrogen, and in the sequestration of carbon to the deep sea. Because the phosphate concentrations of many ocean gyres are low, the bioavailability of the larger, chemically heterogeneous pool of dissolved organic phosphorus could markedly influence Trichodesmium physiology. Here we describe the induction, by phosphorus stress, of genes from the Trichodesmium erythraeum IMS101 genome that are predicted to encode proteins associated with the high-affinity transport and hydrolysis of phosphonate compounds by a carbon-phosphorus lyase pathway. We show the importance of these genes through expression analyses with T. erythraeum from the Sargasso Sea. Phosphonates are known to be present in oligotrophic marine systems, but have not previously been considered to be bioavailable to marine diazotrophs. The apparent absence of genes encoding a carbon-phosphorus lyase pathway in the other marine cyanobacterial genomes suggests that, relative to other phytoplankton, Trichodesmium is uniquely adapted for scavenging phosphorus from organic sources. This adaptation may help to explain the prevalence of Trichodesmium in low phosphate, oligotrophic systems. PMID:16397497

  13. Synthesis and in vitro reactivation study of isonicotinamide derivatives of 2-(hydroxyimino)-N-(pyridin-3-yl)acetamide as reactivators of Sarin and VX inhibited human acetylcholinesterase (hAChE).

    PubMed

    Karade, Hitendra N; Raviraju, G; Acharya, B N; Valiveti, Aditya Kapil; Bhalerao, Uma; Acharya, Jyotiranjan

    2016-09-15

    Previously (Karade et al., 2014), we have reported the synthesis and in vitro evaluation of bis-pyridinium derivatives of pyridine-3-yl-(2-hydroxyimino acetamide), as reactivators of sarin and VX inhibited hAChE. Few of the molecules showed superior in vivo protection efficacy (mice model) (Kumar et al., 2014; Swami et al., 2016) in comparison to 2-PAM against DFP and sarin poisoning. Encouraged by these results, herein we report the synthesis and in vitro evaluation of isonicotinamide derivatives of pyridine-3-yl-(2-hydroxyimino acetamide) (4a-4d) against sarin and VX inhibited erythrocyte ghost hAChE. Reactivation kinetics of these compounds was studied and the determined kinetic parameters were compared with that of commercial reactivators viz. 2-PAM and obidoxime. In comparison to 2-PAM and obidoxime, oxime 4a and 4b exhibited enhanced reactivation efficacy toward sarin inhibited hAChE while oxime 4c showed far greater reactivation efficacy toward VX inhibited hAChE. The acid dissociation constant and IC50 values of these oximes were determined and correlated with the observed reactivation potential. PMID:27450532

  14. Lanthanide complexes of new nonadentate imino-phosphonate ligands derived from 1,4,7-triazacyclononane: synthesis, structural characterisation and NMR studies.

    PubMed

    Tei, Lorenzo; Blake, Alexander J; Wilson, Claire; Schröder, Martin

    2004-07-01

    The polyamino ligand 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane (1) has been used to synthesise two new ligands by Schiff-base condensation with methyl sodium acetyl phosphonate to give ligand L and methyl sodium 4-methoxybenzoyl phosphonate to give ligand L1 in the presence of lanthanide ion as templating agent to form the complexes [Ln(L)] and [Ln(L1)](Ln = Y, La, Gd, Yb). Both ligands L and L1 have nine donor atoms comprising three amine and three imine N-donors and three phosphonate O-donors and form Ln(III) complexes in which the three pendant arms of the ligands wrap around the nine-coordinate Ln(III) centres. Complexes with Y(III), La(III), Gd(III) and Yb(III) have been synthesised and the complexes [Y(L)], [Gd(L)] and [Gd(L1)] have been structurally characterised. In all the complexes the coordination polyhedron about the lanthanide centre is slightly distorted tricapped trigonal prismatic with the two triangular faces of the prism formed by the macrocyclic N-donors and the phosphonate O-donors. Interestingly, given the three chiral phosphorus centres present in [Ln(L)] and [Ln(L1)] complexes, the three crystal structures reported show the presence of only one diastereomer of the four possible. 1H, 13C and 31P NMR spectroscopic studies on diamagnetic [Y(L)] and [La(L)] and on paramagnetic [Yb(L)] complexes indicate the presence in solution of all the four different diastereomers in varying proportions. The stability of complexes [Y(L)] and [Y(L1)] in D2O in both neutral and acidic media, and the relaxivity of the Gd(III) complexes, have also been investigated. PMID:15252581

  15. Probing the interaction of U(VI) with phosphonate-functionalized mesoporous silica using solid-state NMR spectroscopy

    DOE PAGESBeta

    Uribe, Eva C.; Mason, Harris E.; Shusterman, Jennifer A.; Bruchet, Anthony; Nitsche, Heino

    2016-05-30

    The fundamental interaction of U(VI) with diethylphosphatoethyl triethoxysilane functionalized SBA-15 mesoporous silica is studied by macroscopic batch experiments and solid-state NMR spectroscopy. DPTS-functionalized silica has been shown to extract U(VI) from nitric acid solutions at or above pH 3. Extraction is dependent on pH and ionic strength. Single-pulse 31P NMR on U(VI) contacted samples revealed that U(VI)only interacts with a fraction of the ligands present on the surface. At pH 4 the U(VI) extraction capacity of the material is limited to 27–37% of the theoretical capacity, based on ligand loading. We combined single pulse 31P NMR on U(VI)-contacted samples withmore » batch studies to measure a ligand-to-metal ratio of approximately 2 : 1 at pH 3 and 4. Batch studies and cross-polarization NMR measurements reveal that U(VI) binds to deprotonated phosphonate and/or silanol sites. We use 31P–31P DQ-DRENAR NMR studies to compare the average dipolar coupling between phosphorus spins for both U(VI)-complexed and non-complexed ligand environments. Furthermore, these measurements reveal that U(VI) extraction is not limited by inadequate surface distribution of ligands, but rather by low stability of the surface phosphonate complex.« less

  16. A Multifunctional Mn(II) Phosphonate for Rapid Separation of Methyl Orange and Electron-Transfer Photochromism.

    PubMed

    Gao, Chao-Ying; Yang, Yang; Ai, Jing; Tian, Hong-Rui; Li, Lei-Jiao; Yang, Weiting; Dang, Song; Sun, Zhong-Ming

    2016-08-01

    A Mn(II) phosphonate of the general formula [Mn(H2 L)2 (H2 O)2 (H2 bibp)] adopts a layered motif with protonated H2 bibp(2+) cations embedded in the channels (H4 L=thiophene-2-phosphonic acid; bibp=4,4'-bis(1-imidazolyl)biphenyl). The title compound exhibits excellent adsorptive removal of methyl orange (MO) dye from aqueous solution. Its advantageous features include fast adsorption, high uptake capacity, selective removal, and reusability, which are of great significance for practical application in wastewater treatment. Meanwhile, the compound displays rapid photochromism upon irradiation with visible light at room temperature. Extensive research has demonstrated that such behavior is based on a ligand-to-ligand charge-transfer (LLCT) mechanism. The irradiated sample possesses an ultra-long-lived charge-separated state. Moreover, not only is the compound the first Mn-based photochromic MOF, but it is also one of the very few examples showing LLCT with non-photochromic components. PMID:27374008

  17. Probing the interaction of U(vi) with phosphonate-functionalized mesoporous silica using solid-state NMR spectroscopy.

    PubMed

    Uribe, Eva C; Mason, Harris E; Shusterman, Jennifer A; Bruchet, Anthony; Nitsche, Heino

    2016-06-21

    The fundamental interaction of U(vi) with diethylphosphatoethyl triethoxysilane functionalized SBA-15 mesoporous silica is studied by macroscopic batch experiments and solid-state NMR spectroscopy. DPTS-functionalized silica has been shown to extract U(vi) from nitric acid solutions at or above pH 3. Extraction is dependent on pH and ionic strength. Single-pulse (31)P NMR on U(vi) contacted samples revealed that U(vi) only interacts with a fraction of the ligands present on the surface. At pH 4 the U(vi) extraction capacity of the material is limited to 27-37% of the theoretical capacity, based on ligand loading. We combined single pulse (31)P NMR on U(vi)-contacted samples with batch studies to measure a ligand-to-metal ratio of approximately 2 : 1 at pH 3 and 4. Batch studies and cross-polarization NMR measurements reveal that U(vi) binds to deprotonated phosphonate and/or silanol sites. We use (31)P-(31)P DQ-DRENAR NMR studies to compare the average dipolar coupling between phosphorus spins for both U(vi)-complexed and non-complexed ligand environments. These measurements reveal that U(vi) extraction is not limited by inadequate surface distribution of ligands, but rather by low stability of the surface phosphonate complex. PMID:27265020

  18. 2-(Quinolin-4-yloxy)acetamides Are Active against Drug-Susceptible and Drug-Resistant Mycobacterium tuberculosis Strains.

    PubMed

    Pissinate, Kenia; Villela, Anne Drumond; Rodrigues-Junior, Valnês; Giacobbo, Bruno Couto; Grams, Estêvão Silveira; Abbadi, Bruno Lopes; Trindade, Rogério Valim; Roesler Nery, Laura; Bonan, Carla Denise; Back, Davi Fernando; Campos, Maria Martha; Basso, Luiz Augusto; Santos, Diógenes Santiago; Machado, Pablo

    2016-03-10

    2-(Quinolin-4-yloxy)acetamides have been described as potent in vitro inhibitors of Mycobacterium tuberculosis growth. Herein, additional chemical modifications of lead compounds were carried out, yielding highly potent antitubercular agents with minimum inhibitory concentration (MIC) values as low as 0.05 μM. Further, the synthesized compounds were active against drug-resistant strains and were devoid of apparent toxicity to Vero and HaCat cells (IC50s ≥ 20 μM). In addition, the 2-(quinolin-4-yloxy)acetamides showed intracellular activity against the bacilli in infected macrophages with action similar to rifampin, low risk of drug-drug interactions, and no sign of cardiac toxicity in zebrafish (Danio rerio) at 1 and 5 μM. Therefore, these data indicate that this class of compounds may furnish candidates for future development to, hopefully, provide drug alternatives for tuberculosis treatment. PMID:26985307

  19. Phosphonated nanocelluloses from sequential oxidative-reductive treatment-Physicochemical characteristics and thermal properties.

    PubMed

    Sirviö, Juho Antti; Hasa, Tapani; Ahola, Juha; Liimatainen, Henrikki; Niinimäki, Jouko; Hormi, Osmo

    2015-11-20

    Nanocellulosic materials with good thermal stability are highly desirable for applications, such as reinforcement and filler agents in composites. In the present work, phosphonated cellulose was utilized to obtain nanocelluloses with good thermal stability and potential intumescent properties. Phosphonated cellulose was synthetized from birch pulp via sequential periodate oxidation and reductive amination using a bisphosphonate group-containing amine, sodium alendronate, as a phosphonating reagent. After high-pressure homogenization, bisphosphonate cellulose nanofibres or nanocrystals were obtained, depending on the initial oxidation degree. Nanofibres had a typical diameter of 3.8nm and length of several micrometers, whereas nanocrystals exhibited a width of about 6nm and an average length of 103-129nm. All nanocelluloses exhibited cellulose I crystalline structures and high transparency in water solutions. Phosphonated nanocelluloses exhibited good thermal stability and a greater amount of residual char was formed at 700°C compared to birch pulp and mechanically produced, non-chemically modified NFC. PMID:26344310

  20. Transport Properties of LiTFSI-Acetamide Room Temperature Molten Salt Electrolytes Applied in an Li-Ion Battery

    NASA Astrophysics Data System (ADS)

    Yang, Chao-Chen; Hsu, Hsin-Yi; Hsu, Chen-Ruei

    2007-11-01

    In the present work some transport properties of the binary room temperature molten salt (RTMS) lithium bis(trifluoromethane sulfone)imide (LiTFSI)-acetamide [LiN(SO2CF3)2-CH3CONH2], applied in an Li-ion battery, have been investigated. The phase diagram was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The result reveals that the binary RTMS has an eutectic point at 201 K and the 30 mol% LiTFSI composition. The electric conductivity was measured using a direct current computerized method. The result shows that the conductivities of the melts increase with increasing temperature and acetamide content. The densities of all melts decrease with increasing temperature and acetamide content. The equivalent conductivities were fitted by the Arrhenius equation, where the activation energies were 18.15, 18.52, 20.35, 25.08 kJ/mol for 10, 20, 30, 40 mol% LiTFSI, respectively. Besides the relationships between conductivity, density composition and temperature, of the ion interaction is discussed.

  1. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized,...

  2. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized,...

  3. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized,...

  4. Interactions of amino acids, carboxylic acids, and mineral acids with different quinoline derivatives

    NASA Astrophysics Data System (ADS)

    Kalita, Dipjyoti; Deka, Himangshu; Samanta, Shyam Sundar; Guchait, Subrata; Baruah, Jubaraj B.

    2011-03-01

    A series of quinoline containing receptors having amide and ester bonds are synthesized and characterised. The relative binding abilities of these receptors with various amino acids, carboxylic acids and mineral acids are determined by monitoring the changes in fluorescence intensity. Among the receptors bis(2-(quinolin-8-yloxy)ethyl) isophthalate shows fluorescence enhancement on addition of amino acids whereas the other receptors shows fluorescence quenching on addition of amino acids. The receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy) propanamide has higher binding affinity for amino acids. However, the receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide having similar structure do not bind to amino acids. This is attributed to the concave structure of the former which is favoured due to the presence of methyl substituent. The receptor bis(2-(quinolin-8-yloxy)ethyl) isophthalate do not bind to hydroxy carboxylic acids, but is a good receptor for dicarboxylic acids. The crystal structure of bromide and perchlorate salts of receptor 2-bromo-N-(quinolin-8-yl)-propanamide are determined. In both the cases the amide groups are not in the plane of quinoline ring. The structure of N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide, N-(2-methoxyphenethyl)-2-(quinolin-8-yloxy)acetamide and their salts with maleic acid as well as fumaric acid are determined. It is observed that the solid state structures are governed by the double bond geometry of these two acid. Maleic acid forms salt in both the cases, whereas fumaric acid forms either salt or co-crystals.

  5. A Novel Multi-Phosphonate Surface Treatment of Titanium Dental Implants: A Study in Sheep

    PubMed Central

    von Salis-Soglio, Marcella; Stübinger, Stefan; Sidler, Michéle; Klein, Karina; Ferguson, Stephen J.; Kämpf, Käthi; Zlinszky, Katalin; Buchini, Sabrina; Curno, Richard; Péchy, Péter; Aronsson, Bjorn-Owe; von Rechenberg, Brigitte

    2014-01-01

    The aim of the present study was to evaluate a new multi-phosphonate surface treatment (SurfLink®) in an unloaded sheep model. Treated implants were compared to control implants in terms of bone to implant contact (BIC), bone formation, and biomechanical stability. The study used two types of implants (rough or machined surface finish) each with either the multi-phosphonate Wet or Dry treatment or no treatment (control) for a total of six groups. Animals were sacrificed after 2, 8, and 52 weeks. No adverse events were observed at any time point. At two weeks, removal torque showed significantly higher values for the multi-phosphonate treated rough surface (+32% and +29%, Dry and Wet, respectively) compared to rough control. At 52 weeks, a significantly higher removal torque was observed for the multi-phosphonate treated machined surfaces (+37% and 23%, Dry and Wet, respectively). The multi-phosphonate treated groups showed a positive tendency for higher BIC with time and increased new-old bone ratio at eight weeks. SEM images revealed greater amounts of organic materials on the multi-phosphonate treated compared to control implants, with the bone fracture (from the torque test) appearing within the bone rather than at the bone to implant interface as it occurred for control implants. PMID:25215424

  6. A novel multi-phosphonate surface treatment of titanium dental implants: a study in sheep.

    PubMed

    von Salis-Soglio, Marcella; Stübinger, Stefan; Sidler, Michéle; Klein, Karina; Ferguson, Stephen J; Kämpf, Käthi; Zlinszky, Katalin; Buchini, Sabrina; Curno, Richard; Péchy, Péter; Aronsson, Bjorn-Owe; von Rechenberg, Brigitte

    2014-01-01

    The aim of the present study was to evaluate a new multi-phosphonate surface treatment (SurfLink®) in an unloaded sheep model. Treated implants were compared to control implants in terms of bone to implant contact (BIC), bone formation, and biomechanical stability. The study used two types of implants (rough or machined surface finish) each with either the multi-phosphonate Wet or Dry treatment or no treatment (control) for a total of six groups. Animals were sacrificed after 2, 8, and 52 weeks. No adverse events were observed at any time point. At two weeks, removal torque showed significantly higher values for the multi-phosphonate treated rough surface (+32% and +29%, Dry and Wet, respectively) compared to rough control. At 52 weeks, a significantly higher removal torque was observed for the multi-phosphonate treated machined surfaces (+37% and 23%, Dry and Wet, respectively). The multi-phosphonate treated groups showed a positive tendency for higher BIC with time and increased new-old bone ratio at eight weeks. SEM images revealed greater amounts of organic materials on the multi-phosphonate treated compared to control implants, with the bone fracture (from the torque test) appearing within the bone rather than at the bone to implant interface as it occurred for control implants. PMID:25215424

  7. Identification of N-phenyl-2-(N-phenylphenylsulfonamido)acetamides as new RORγ inverse agonists: Virtual screening, structure-based optimization, and biological evaluation.

    PubMed

    Song, Yu; Xue, Xiaoqian; Wu, Xishan; Wang, Rui; Xing, Yanli; Yan, Weiqun; Zhou, Yulai; Qian, Chao-Nan; Zhang, Yan; Xu, Yong

    2016-06-30

    Retinoic acid receptor-related orphan receptors (RORs) are ligand-dependent transcriptional factors and members of the nuclear receptor superfamily. RORs regulate inflammation, metabolic disorders and circadian rhythm. RORγ is a promising therapeutic drug target for treating Th17-mediated autoimmune diseases. In our study, we performed structure-based virtual screening and ligand-based virtual screening targeting the RORγ ligand-binding domain and successfully identified N-phenyl-2-(N-phenylphenylsulfonamido) acetamides as a type of RORγ inverse agonist. Among the 28 purchased compounds, C11 was confirmed to be active with micromolar IC50 values in both an AlphaScreen assay (62.58 μM) and a cell-based reporter gene assay (4.54 μM). Structure-guided optimization of the compound C11 led to the identification of compound 39, which significantly enhanced RORγ inhibition with an IC50 value of 630 nM. The RORγ antagonism of 39 was 7-fold higher than that of hit compound C11. These results represent a promising starting point for developing potent small molecule RORγ inverse agonists for the treatment of autoimmune diseases, such as rheumatoid arthritis, psoriasis, and multiple sclerosis. PMID:27043267

  8. Synthesis of 2-{(5-phenyl-1,3,4-Oxadiazol-2-yl)sulfanyl}-N-substituted acetamides as potential antimicrobial and hemolytic agents.

    PubMed

    Rehman, Aziz-ur; Abbasi, Muhammad Athar; Siddiqui, Sabahat Zahra; Ahmad, Irshad; Shahid, Muhammad; Subhani, Zinayyera

    2016-05-01

    A new series of N-substituted derivatives of 2-{(5-phenyl-1,3,4-Oxadiazol-2-yl)sulfanyl}acetamides was synthesized. The synthesis was carried out by converting benzoic acid (1) into ethyl benzoate (2), benzohydrazide (3) and then 5-pheny-1,3,4-Oxadiazol-2-thiol (4) step by st0ep. The target compounds 6a-p were synthesized by reaction of compound 4 with equimolar ratios of different N-alkyl/aryl substituted 2-bromoacetamide (5a-p) in the presence of DMF and sodium hydride (NaH). The spectral (EI-MS, IR, (1)H-NMR) characterization of all the synthesized compounds reveal their successful synthesis. The compounds were also screened for antimicrobial & hemolytic activity and most of them were found to be active against the selected microbial species at variable extent relative to reference standards. But 6h was the most active against the selected panel of microbes. This series showed less toxicity and may be considered for further biological screening and application trial except 6m, possessing higher cytotoxicity. PMID:27166551

  9. Probing the influence of phosphonate bonding modes to uranium(VI) on structural topology and stability: a complementary experimental and computational investigation.

    PubMed

    Zheng, Tao; Wu, Qun-Yan; Gao, Yang; Gui, Daxiang; Qiu, Shiwen; Chen, Lanhua; Sheng, Daopeng; Diwu, Juan; Shi, Wei-Qun; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

    2015-04-20

    Systematic control of the reactions between U(VI) and 1,4-phenylenebis(methylene))bis(phosphonic acid) (pmbH4) allows for alterations in the bonding between these constituents and affords three uranyl phosphonate compounds with chiral one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) structures, namely, [TPA][UO2(pmbH3)(pmbH2)H2O]·2H2O (1), [NH4]2[UO2(pmb)] (2), UO2(pmbH2) (3), and the first uranyl mixed phosphite/phosphonate compound [TMA]2[(UO2)2(pmb)(HPO3)] (4) (TPA = NPr4+, TMA = NMe4+). These compounds crystallize in the space groups P212121, P1̅, P21/c, and Cmcm, respectively. Further investigation of the local uranyl coordination environment reveals that in 1 only oxygen atoms from P=O moieties ligate the uranium centers; whereas in 2 only P-O(-) oxygen atoms are involved in bonding and yield a layered topology. Compound 3 differs sharply from the first two in that conjugated P=O and P-O(-) oxygen atoms chelate the uranium centers resulting in a 3D framework. In compound 4, a phosphonate group bridges three uranyl centers further coordinated with a phosphite ligand HPO32–, which is a product of pmbH4 decomposing, forming a 2D layered structure. Compounds 3 and 4 also contain a different coordination environment for U(VI) than that found in 1 or 2. In this case, tetragonal bipyramidal UO6 units occur instead of the far more common UO7 pentagonal bipyramids found in 1 and 2. Interestingly, 1 converts to 3 at elevated reaction temperatures, indicating that the formation of 1 is likely under kinetic control. This is supported by thermal analysis, which reveals that 3 has higher thermal stability than 1 or 2. UV-vis-near-IR absorption and fluorescence spectroscopy show that the absorption and photoluminescence intensity increases from 1 to 4. Density functional theory electronic structure calculations provide insight into the nature of the interactions between U(VI) and the phosphonate ligands. PMID:25815698

  10. Dielectric Relaxations of (Acetamide + Electrolyte) Deep Eutectic Solvents in the Frequency Window, 0.2 ≤ ν/GHz ≤ 50: Anion and Cation Dependence.

    PubMed

    Mukherjee, Kallol; Das, Anuradha; Choudhury, Samiran; Barman, Anjan; Biswas, Ranjit

    2015-06-25

    Dielectric relaxation (DR) measurements in the frequency range 0.2 ≤ ν/GHz ≤ 50 have been carried out for neat molten acetamide and six different (acetamide + electrolyte) deep eutectic solvents (DESs) for investigating ion effects on DR dynamics in these ionic DESs. Electrolytes used are lithium salts of bromide (LiBr), nitrate (LiNO3), and perchlorate (LiClO4); sodium salts of perchlorate (NaClO4) and thiocyante (NaSCN); and potassium thiocyanate (KSCN). With these electrolytes acetamide forms DESs approximately at an 80:20 mol ratio. Simultaneous fits to the measured permittivity (ε′) and loss (ε″) spectra of these DESs at ∼293 K require a sum of four Debye (4-D) processes with relaxation times spread over picosecond to nanosecond regime. In contrast, DR spectra for neat molten acetamide (∼354 K) depict 2-D relaxation with time constants ∼50 ps and ∼5 ps. For both the neat and ionic systems, the undetected dispersion, ε∞ – n(D)2, remains to be ∼3–4. Upon comparison, measured DR dynamics reveal pronounced anion and cation effects. Estimated static dielectric constants (ε0) from fits for these DESs cover the range 12 < ε0 < 30 and are remarkably lower than that (ε0 ∼ 64) measured for molten acetamide at ∼354 K. Hydrodynamic effective rotation volumes (Veff) estimated from the slowest DR relaxation time constants vary with ion identity and are much smaller than the molecular volume of acetamide. This decrease of ε0 and Veff is attributed respectively to the pinning of acetamide molecules by ions and orientation jumps and undetected portion to the limited frequency coverage employed in these measurements PMID:26012789

  11. Rapid Synthesis and Antiviral Activity of (Quinazolin-4-Ylamino)Methyl-Phosphonates Through Microwave Irradiation

    PubMed Central

    Luo, Hui; Hu, Deyu; Wu, Jian; He, Ming; Jin, Linhong; Yang, Song; Song, Baoan

    2012-01-01

    This study describes the simple synthesis of new (quinazolin-4-ylamino) methylphosphonates via microwave irradiation. Substituted-2-aminobenzonitrile reacted with 1,1-dimethoxy-N,N-dimethylmethanamine at a reflux condition to obtain N′-(substituted-2-cyanophenyl)-N,N-dimethylformamidine (1). The subsequent reaction of this intermediate product with α-aminophosphonate (2) in a solution containing glacial acetic acid in 2-propanol through microwave irradiation resulted in the formation of (quinazolin-4-ylamino)methyl-phosphonate derivatives 3a to 3x, which were unequivocally characterized by the spectral data and elemental analysis. The influence of the reaction conditions on the yield of 3a was investigated to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 3a include a 1:1 molar ratio of N′-(2-cyanophenyl)-N,N-dimethylformamidine to diethyl amino(phenyl)methylphosphonate and a 4:1 volume ratio of isopropanol to HOAc in the solvent mixture, at a reaction temperature of 150 °C, with a microwave power of 100 W and a corresponding pressure of 150 psi for 20 min in the microwave synthesizer. The yield of 3a was approximately 79%, whereas those of 3b to 3x were approximately 77% to 86%. Some of the synthesized compounds displayed weak to good anti-Tobacco mosaic virus (TMV) activity. PMID:22837660

  12. Adsorption of phosphonate antiscalant from reverse osmosis membrane concentrate onto granular ferric hydroxide.

    PubMed

    Boels, Luciaan; Keesman, Karel J; Witkamp, Geert-Jan

    2012-09-01

    Adsorptive removal of antiscalants offers a promising way to improve current reverse osmosis (RO) concentrate treatment processes and enables the reuse of the antiscalant in the RO desalination process. This work investigates the adsorption and desorption of the phosphonate antiscalant nitrilotris(methylenephosphonic acid) (NTMP) from RO membrane concentrate onto granular ferric hydroxide (GFH), a material that consists predominantly of akaganéite. The kinetics of the adsorption of NTMP onto GFH was predicted fairly well with two models that consider either combined film-pore or combined film-surface diffusion as the main mechanism for mass transport. It is also demonstrated that NTMP is preferentially adsorbed over sulfate by GFH at pH 7.85. The presence of calcium causes a transformation in the equilibrium adsorption isotherm from a Langmuir type to a Freundlich type with much higher adsorption capacities. Furthermore, calcium also increases the rate of adsorption substantially. GFH is reusable after regeneration with sodium hydroxide solution, indicating that NTMP can be potentially recovered from the RO concentrate. This work shows that GFH is a promising adsorbent for the removal and recovery of NTMP antiscalant from RO membrane concentrates. PMID:22873428

  13. Structural basis of allosteric and synergistic activation of AMPK by furan-2-phosphonic derivative C2 binding

    PubMed Central

    Langendorf, Christopher G.; Ngoei, Kevin R. W.; Scott, John W.; Ling, Naomi X. Y.; Issa, Sam M. A.; Gorman, Michael A.; Parker, Michael W.; Sakamoto, Kei; Oakhill, Jonathan S.; Kemp, Bruce E.

    2016-01-01

    The metabolic stress-sensing enzyme AMP-activated protein kinase (AMPK) is responsible for regulating metabolism in response to energy supply and demand. Drugs that activate AMPK may be useful in the treatment of metabolic diseases including type 2 diabetes. We have determined the crystal structure of AMPK in complex with its activator 5-(5-hydroxyl-isoxazol-3-yl)-furan-2-phosphonic acid (C2), revealing two C2-binding sites in the γ-subunit distinct from nucleotide sites. C2 acts synergistically with the drug A769662 to activate AMPK α1-containing complexes independent of upstream kinases. Our results show that dual drug therapies could be effective AMPK-targeting strategies to treat metabolic diseases. PMID:26952388

  14. Sorption of beryllium from fluorine-containing solutions by amino-phosphonate amphoteric ion-exchange resins

    SciTech Connect

    Pakholkov, V.S.; Rychkov, V.N.

    1981-10-20

    Sorption of beryllium ions by a series of amino-phosphonate amphoteric ion-exchange resins from BeF/sub 2/ solutions containing HF, NH/sub 4/F.HF, and NH/sub 4/F has been studied. The influence of the salt form of the resin, concentration of fluoride ions, and beryllium content in the original solutions was demonstrated. The mechanism of ion exchange on amphoteric ion-exchangers was postulated on the basis of chemical analysis and sorption and IR-spectroscopic data. Conclusions are drawn regarding the participation of phosphorus-containing groups of the resins in exchange. Data are presented on desorption of complex fluoride ions and beryllium from amphoteric ion-exchange resins by solutions of hydrofluoric, hydrochloric, and sulfuric acids, ammonium fluoride, and ammonium hydrogenfluoride.

  15. Disorder-derived, strong tunneling attenuation in bis-phosphonate monolayers

    NASA Astrophysics Data System (ADS)

    Pathak, Anshuma; Bora, Achyut; Liao, Kung-Ching; Schmolke, Hannah; Jung, Antje; Klages, Claus-Peter; Schwartz, Jeffrey; Tornow, Marc

    2016-03-01

    Monolayers of alkyl bisphosphonic acids (bisPAs) of various carbon chain lengths (C4, C8, C10, C12) were grown on aluminum oxide (AlO x ) surfaces from solution. The structural and electrical properties of these self-assembled monolayers (SAMs) were compared with those of alkyl monophosphonic acids (monoPAs). Through contact angle (CA) and Kelvin-probe (KP) measurements, ellipsometry, and infrared (IR) and x-ray photoelectron (XPS) spectroscopies, it was found that bisPAs form monolayers that are relatively disordered compared to their monoPA analogs. Current-voltage (J-V) measurements made with a hanging Hg drop top contact show tunneling to be the prevailing transport mechanism. However, while the monoPAs have an observed decay constant within the typical range for dense monolayers, β mono  =  0.85  ±  0.03 per carbon atom, a surprisingly high value, β bis  =  1.40  ±  0.05 per carbon atom, was measured for the bisPAs. We attribute this to a strong contribution of ‘through-space’ tunneling, which derives from conformational disorder in the monolayer due to strong interactions of the distal phosphonic acid groups; they likely form a hydrogen-bonding network that largely determines the molecular layer structure. Since bisPA SAMs attenuate tunnel currents more effectively than do the corresponding monoPA SAMs, they may find future application as gate dielectric modification in organic thin film devices.

  16. Disorder-derived, strong tunneling attenuation in bis-phosphonate monolayers.

    PubMed

    Pathak, Anshuma; Bora, Achyut; Liao, Kung-Ching; Schmolke, Hannah; Jung, Antje; Klages, Claus-Peter; Schwartz, Jeffrey; Tornow, Marc

    2016-03-01

    Monolayers of alkyl bisphosphonic acids (bisPAs) of various carbon chain lengths (C4, C8, C10, C12) were grown on aluminum oxide (AlO(x)) surfaces from solution. The structural and electrical properties of these self-assembled monolayers (SAMs) were compared with those of alkyl monophosphonic acids (monoPAs). Through contact angle (CA) and Kelvin-probe (KP) measurements, ellipsometry, and infrared (IR) and x-ray photoelectron (XPS) spectroscopies, it was found that bisPAs form monolayers that are relatively disordered compared to their monoPA analogs. Current-voltage (J-V) measurements made with a hanging Hg drop top contact show tunneling to be the prevailing transport mechanism. However, while the monoPAs have an observed decay constant within the typical range for dense monolayers, β(mono)  =  0.85  ±  0.03 per carbon atom, a surprisingly high value, β(bis) =  1.40  ±  0.05 per carbon atom, was measured for the bisPAs. We attribute this to a strong contribution of 'through-space' tunneling, which derives from conformational disorder in the monolayer due to strong interactions of the distal phosphonic acid groups; they likely form a hydrogen-bonding network that largely determines the molecular layer structure. Since bisPA SAMs attenuate tunnel currents more effectively than do the corresponding monoPA SAMs, they may find future application as gate dielectric modification in organic thin film devices. PMID:26871412

  17. Investigation of Antifouling Properties of Surfaces Featuring Zwitterionic α-Aminophosphonic Acid Moieties.

    PubMed

    Wagner, Natalie; Zimmermann, Phyllis; Heisig, Peter; Klitsche, Franziska; Maison, Wolfgang; Theato, Patrick

    2015-12-01

    Zwitterionic thin films containing α-amino phosphonic acid moieties were successfully introduced on silicon surfaces and their antifouling properties were investigated. Initially, the substrates were modified with a hybrid polymer, composed of poly(methylsilsesquioxane) (PMSSQ) and poly(4-vinyl benzaldehyde) (PStCHO). Next, a Kabachnik-Fields post-polymerization modification (sur-KF-PMR) of the functionalized aldehyde surfaces was conducted with different amines and dialkyl phosphonates. After subsequent deprotection reaction of dialkyl phosphonates, the obtained zwitterionic surfaces were characterized by various techniques and we found excellent antifouling properties of the resulting films. PMID:26332285

  18. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... diazotized 2,5-diethoxybenzenamine. (a) Chemical substance and significant new uses subject to reporting. (1... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid...

  19. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... diazotized 2,5-diethoxybenzenamine. (a) Chemical substance and significant new uses subject to reporting. (1... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid...

  20. N-Heterocyclic carbene catalysed 1,6-hydrophosphonylation of p-quinone methides and fuchsones: an atom economical route to unsymmetrical diaryl- and triarylmethyl phosphonates.

    PubMed

    Arde, Panjab; Vijaya Anand, Ramasamy

    2016-06-15

    A convenient organocatalytic approach to access unsymmetrical diaryl- and triarylmethyl phosphonates using NHC as a Brønsted base catalyst is described. This atom-economical protocol enables the installation of phosphonate groups on p-quinone methides and fuchsones through a 1,6-conjugate addition of dialkylphosphites, and the corresponding phosphonates were obtained in excellent yields. PMID:26924164

  1. Characterization and structure of DhpI, a phosphonate O-methyltransferase involved in dehydrophos biosynthesis

    SciTech Connect

    Lee, Jin-Hee; Bae, Brian; Kuemin, Michael; Circello, Benjamin T.; Metcalf, William W.; Nair, Satish K.; van der Donk, Wilfred A.

    2012-03-15

    Phosphonate natural products possess a range of biological activities as a consequence of their ability to mimic phosphate esters or tetrahedral intermediates formed in enzymatic reactions involved in carboxyl group metabolism. The dianionic form of these compounds at pH 7 poses a drawback with respect to their ability to mimic carboxylates and tetrahedral intermediates. Microorganisms producing phosphonates have evolved two solutions to overcome this hurdle: biosynthesis of monoanionic phosphinates containing two P-C bonds or esterification of the phosphonate group. The latter solution was first discovered for the antibiotic dehydrophos that contains a methyl ester of a phosphonodehydroalanine group. We report here the expression, purification, substrate scope, and structure of the O-methyltransferase from the dehydrophos biosynthetic gene cluster. The enzyme utilizes S-adenosylmethionine to methylate a variety of phosphonates including 1-hydroxyethylphosphonate, 1,2-dihydroxyethylphosphonate, and acetyl-1-aminoethylphosphonate. Kinetic analysis showed that the best substrates are tripeptides containing as C-terminal residue a phosphonate analog of alanine suggesting the enzyme acts late in the biosynthesis of dehydrophos. These conclusions are corroborated by the X-ray structure that reveals an active site that can accommodate a tripeptide substrate. Furthermore, the structural studies demonstrate a conformational change brought about by substrate or product binding. Interestingly, the enzyme has low substrate specificity and was used to methylate the clinical antibiotic fosfomycin and the antimalaria clinical candidate fosmidomycin, showing its promise for applications in bioengineering.

  2. Characterization and structure of DhpI, a phosphonate O-methyltransferase involved in dehydrophos biosynthesis.

    PubMed

    Lee, Jin-Hee; Bae, Brian; Kuemin, Michael; Circello, Benjamin T; Metcalf, William W; Nair, Satish K; van der Donk, Wilfred A

    2010-10-12

    Phosphonate natural products possess a range of biological activities as a consequence of their ability to mimic phosphate esters or tetrahedral intermediates formed in enzymatic reactions involved in carboxyl group metabolism. The dianionic form of these compounds at pH 7 poses a drawback with respect to their ability to mimic carboxylates and tetrahedral intermediates. Microorganisms producing phosphonates have evolved two solutions to overcome this hurdle: biosynthesis of monoanionic phosphinates containing two P-C bonds or esterification of the phosphonate group. The latter solution was first discovered for the antibiotic dehydrophos that contains a methyl ester of a phosphonodehydroalanine group. We report here the expression, purification, substrate scope, and structure of the O-methyltransferase from the dehydrophos biosynthetic gene cluster. The enzyme utilizes S-adenosylmethionine to methylate a variety of phosphonates including 1-hydroxyethylphosphonate, 1,2-dihydroxyethylphosphonate, and acetyl-1-aminoethylphosphonate. Kinetic analysis showed that the best substrates are tripeptides containing as C-terminal residue a phosphonate analog of alanine suggesting the enzyme acts late in the biosynthesis of dehydrophos. These conclusions are corroborated by the X-ray structure that reveals an active site that can accommodate a tripeptide substrate. Furthermore, the structural studies demonstrate a conformational change brought about by substrate or product binding. Interestingly, the enzyme has low substrate specificity and was used to methylate the clinical antibiotic fosfomycin and the antimalaria clinical candidate fosmidomycin, showing its promise for applications in bioengineering. PMID:20876132

  3. The effect of deuterium substitution in the amino group on the internal-rotation barrier of acetamide

    NASA Astrophysics Data System (ADS)

    Hirota, Eizi; Kawashima, Yoshiyuki; Usami, Tsuyoshi; Seto, Koichi

    2010-03-01

    Peptide molecules XCO-NYY' are characterized by low potential barrier V3 to internal rotation of a methyl group substituted for X and/or Y. A most conspicuous example is acetamide, for which V3 was previously reported to be 25.043857(19) cm -1[8]. The present study intended to clarify why V3 is so low in acetamide, by examining the effect of the out-of-plane bending or inversion of the amino group on the molecular structure through deuterium substitution for amino hydrogens. The potential barrier V3 in acetamide was found to decrease by 2.630, 2.986, and 5.532 cm -1, when H's at cis, trans, and both positions in the amino group were replaced by deuterium atoms, respectively. The reduction was proportional to the effective mass of the out-of-plane bending mode of the amino group (hereafter referred to as the amino inversion), which was in turn ascribed to the change in electronic resonance character of the peptide linkage. The amino inversion is coupled with the CH 3 internal rotation, producing an interaction term proportional to τ sin 3 α, where τ and α denote the amino inversion and methyl internal rotation angles, respectively. This coupling term, when the inversion is treated by second-order perturbation, yields a V6 term in the internal-rotation potential function of the methyl group, in agreement with the finding of Ilyushin et al. [8], who derived an unusually large V6 term of -10.044874(73) cm -1. It is quite interesting that even a small perturbation such as deuterium substitution causes a substantial change in electronic structure of the peptide linkage.

  4. THE AMPHOTERIC PROPERTIES OF SOME AMINO-ACIDS AND PEPTIDES.

    PubMed

    Eckweiler, H; Noyes, H M; Falk, K G

    1921-01-20

    The titration curves of solutions of glycine, alanine, alpha-ammo-butyric acid, leucine, glycyl-glycine, alanyl-glycine, alanyl-alanine, acetone, acetamide, urea, acetic acid, and aceturic acid were determined and some of the relations as dependent upon the chemical structures discussed. The isoelectric points of some of the amphoteric electrolytes were found experimentally. The definition of isoelectric point, its theoretical significance, and method of calculation were considered in some detail. PMID:19871865

  5. Crystallographic structure of a phosphonate derivative of the Enterobacter cloacae P99 cephalosporinase: mechanistic interpretation of a beta-lactamase transition-state analog.

    PubMed

    Lobkovsky, E; Billings, E M; Moews, P C; Rahil, J; Pratt, R F; Knox, J R

    1994-06-01

    The crystal structure of a complex formed on reaction of the Enterobacter cloacae P99 cephalosporinase (beta-lactamase) with a phosphonate monoester inhibitor, m-carboxyphenyl [[N-[(p-iodophenyl)acetyl]amino]methyl]phosphonate, has been obtained at 2.3-A resolution. The structure shows that the inhibitor has phosphonylated the active site serine (Ser64) with loss of the m-carboxyphenol leaving group. The inhibitor is positioned in the active site in a way that can be interpreted in terms of a transition-state analog. The arylacetamido side chain is placed as anticipated from analogous beta-lactamoyl complexes of penicillin-recognizing enzymes, with the amino group hydrogen-bonded to the backbone carbonyl of Ser318 (of the B3 beta-strand) and to the amides of Gln120 and Asn152. There is support in the asymmetry of the hydrogen bonding of this side chain to the protein and in the 2-fold disorder of the benzyl group for the considerable breadth in substrate specificity exhibited by class C beta-lactamases. One phosphonyl oxygen atom is in the oxyanion hole, hydrogen-bonded to main-chain NH groups of Ser318 and Ser64, while the other oxygen is solvated, not within hydrogen-bonding distance of any amino acid side chain. The closest active site functional group to the solvated oxygen atom is the Tyr150 hydroxyl group (3.4A); Lys67 and Lys315 are quite distant (4.3 and 5.7 A, respectively). Rather, Tyr150 and Lys67 are more closely associated with Ser64O gamma (2.9 and 3.3 A). This arrangement is interpreted in terms of the transition state for breakdown of the tetrahedral intermediate in the deacylation step of catalysis, where the Tyr150 phenol seems the most likely general acid. Thus, Tyr150, as the phenoxide anion, would be the general base catalyst in acylation, as proposed by Oefner et al. [Nature (1990) 343, 284-288]. The structure is compared with that of a similar phosphonate derivative of a class A beta-lactamase [Chen et al. (1993) J. Mol. Biol. 234, 165

  6. Incorporation of Phosphonate into Benzonaphthyridine Toll-like Receptor 7 Agonists for Adsorption to Aluminum Hydroxide.

    PubMed

    Cortez, Alex; Li, Yongkai; Miller, Andrew T; Zhang, Xiaoyue; Yue, Kathy; Maginnis, Jillian; Hampton, Janice; Hall, De Shon; Shapiro, Michael; Nayak, Bishnu; D'Oro, Ugo; Li, Chun; Skibinski, David; Mbow, M Lamine; Singh, Manmohan; O'Hagan, Derek T; Cooke, Michael P; Valiante, Nicholas M; Wu, Tom Y-H

    2016-06-23

    Small molecule Toll-like receptor 7 (TLR7) agonists have been used as vaccine adjuvants by enhancing innate immune activation to afford better adaptive response. Localized TLR7 agonists without systemic exposure can afford good adjuvanticity, suggesting peripheral innate activation (non-antigen-specific) is not required for immune priming. To enhance colocalization of antigen and adjuvant, benzonaphthyridine (BZN) TLR7 agonists are chemically modified with phosphonates to allow adsorption onto aluminum hydroxide (alum), a formulation commonly used in vaccines for antigen stabilization and injection site deposition. The adsorption process is facilitated by enhancing aqueous solubility of BZN analogs to avoid physical mixture of two insoluble particulates. These BZN-phosphonates are highly adsorbed onto alum, which significantly reduced systemic exposure and increased local retention post injection. This report demonstrates a novel approach in vaccine adjuvant design using phosphonate modification to afford adsorption of small molecule immune potentiator (SMIP) onto alum, thereby enhancing co-delivery with antigen. PMID:27270029

  7. Yield Improvement and Energy Savings Uing Phosphonates as Additives in Kraft pulping

    SciTech Connect

    Ulrike W. Tschirner; Timothy Smith

    2007-03-31

    Project Objective: Develop a commercially viable modification to the Kraft process resulting in energy savings, increased yield and improved bleachability. Evaluate the feasibility of this technology across a spectrum of wood species used in North America. Develop detailed fundamental understanding of the mechanism by which phosphonates improve KAPPA number and yield. Evaluate the North American market potential for the use of phosphonates in the Kraft pulping process. Examine determinants of customer perceived value and explore organizational and operational factors influencing attitudes and behaviors. Provide an economic feasibility assessment for the supply chain, both suppliers (chemical supply companies) and buyers (Kraft mills). Provide background to most effectively transfer this new technology to commercial mills.

  8. Surface engineering of SPIONs: role of phosphonate ligand multivalency in tailoring their efficacy.

    PubMed

    Lam, Tina; Avti, Pramod K; Pouliot, Philippe; Tardif, Jean-Claude; Rhéaume, Éric; Lesage, Frederic; Kakkar, Ashok

    2016-10-14

    We report the design of scaffolds containing mono-, bis-, and tris-phosphonate coordinating groups, and a polyethylene glycol chain, for stabilizing superparamagnetic iron oxide nanoparticles (SPIONs), using simple and versatile chemistry. We demonstrate that the number of anchoring phosphonate sites on the ligand influence the colloidal stability, magnetic and biological properties of SPIONs, and the latter do not solely depend on attaching moieties that can enhance their aqueous dispersion. These parameters can be tailored by the number of conjugation sites on the ligand, as evidenced from dynamic light scattering at various salt concentrations, magnetic relaxivities and cell viability studies. PMID:27608753

  9. Design of a humidity-stable metal-organic framework using a phosphonate monoester ligand.

    PubMed

    Gelfand, Benjamin S; Lin, Jian-Bin; Shimizu, George K H

    2015-02-16

    Phosphonate monoesters are atypical linkers for metal-organic frameworks, but they offer potentially added versatility. In this work, a bulky isopropyl ester is used to direct the topology of a copper(II) network from a dense to an open framework, CALF-30. CALF-30 shows no adsorption of N2 or CH4 however, using CO2 sorption, CALF-30 was found to have a Langmuir surface area of over 300 m(2)/g and to be stable to conditions of 90% relative humidity at 353 K owing to kinetic shielding of the framework by the phosphonate ester. PMID:25646642

  10. Unsaturated Phosphonates as Hauser Acceptors for the Synthesis of Phosphonylated Dihydroxynaphthalenes and Naphthoquinones.

    PubMed

    Chaturvedi, Atul Kumar; Rastogi, Namrata

    2016-04-15

    The unsaturated phosphonates were utilized as Hauser acceptors successfully for the first time. The products phosphonylated 1,4-dihydroxynaphthalenes were isolated in good yields in short reaction time and were further oxidized to the corresponding 1,4-naphthoquinones in quantitative yields. The reaction provides an efficient and straightforward approach for the synthesis of pharmacologically privileged disubstituted naphthalene-1,4-diols and naphtha-1,4-diones bearing a phosphonate group at the 2-position and various (het)aryl groups at the 3-position. PMID:27049927

  11. Microbial transformations in phosphonate biosynthesis and catabolism, and their importance in nutrient cycling.

    PubMed

    Chin, Jason P; McGrath, John W; Quinn, John P

    2016-04-01

    Phosphorus cycling in the biosphere has traditionally been thought to involve almost exclusively transformations of the element in its pentavalent oxidation state. Recent evidence, however, suggests that a significant fraction of environmental phosphorus may exist in a more reduced form. Most abundant of these reduced phosphorus compounds are the phosphonates, with their direct carbon-phosphorus bonds, and striking progress has recently been made in elucidating the biochemistry of microbial phosphonate transformations. These advances are now presented in the context of their contribution to our understanding of phosphorus biogeochemistry and of such diverse fields as the productivity of the oceans, marine methanogenesis and the discovery of novel microbial antimetabolites. PMID:26836350

  12. Synthesis of α-L-threose nucleoside phosphonates via regioselective sugar protection.

    PubMed

    Dumbre, Shrinivas G; Jang, Mi-Yeon; Herdewijn, Piet

    2013-07-19

    A new synthesis route to α-L-threose nucleoside phosphonates via 2-O and 3-O selectively protected L-threose is developed. The key intermediates 2-O-benzoyl-L-threonolactone and 1-O-acetyl-2-O-benzoyl-3-O-t-butyldiphenylsilyl-L-threofuranose were functionalized to synthesize 2'-deoxy-2'-fluoro- and 3'-C-ethynyl L-threose 3'-O-phosphonate nucleosides. The key intermediates developed are important intermediates for the synthesis of new L-threose-based nucleoside analogues, TNA phosphoramidites, and TNA triphosphates. PMID:23822647

  13. Monitoring 2-phenylethanamine and 2-(3-hydroxyphenyl)acetamide sulfate in doping controls.

    PubMed

    Sigmund, Gerd; Dib, Josef; Tretzel, Laura; Piper, Thomas; Bosse, Christina; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    2-Phenylethanamine (phenethylamine, PEA) represents the core structure of numerous drugs with stimulant-like properties and is explicitly featured as so-called specified substance on the World Anti-Doping Agency (WADA) Prohibited List. Due to its natural occurrence in humans as well as its presence in dietary products, studies concerning the ability of test methods to differentiate between an illicit intake and the renal elimination of endogenously produced PEA were indicated. Following the addition of PEA to the Prohibited List in January 2015, retrospective evaluation of routine doping control data of 10 190 urine samples generated by combined gas chromatography-mass spectrometry and nitrogen phosphorus-specific detection (GC-MS/NPD) was performed. Signals for PEA at approximate concentrations > 500 ng/mL were observed in 31 cases (0.3%), which were subjected to a validated isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) test method for accurate quantification of the target analyte. Further, using elimination study urine samples collected after a single oral administration of 250 mg of PEA hydrochloride to two healthy male volunteers, two tentatively identified metabolites of PEA were observed and evaluated concerning their utility as discriminative markers for PEA intake. The ID-LC-MS/MS approach was extended to allow for the simultaneous detection of PEA and 2-(3-hydroxyphenyl)acetamide sulfate (M1), and concentration ratios of M1 and PEA were calculated for elimination study urine samples and a total of 205 doping control urine samples that returned findings for PEA at estimated concentrations of 50-2500 ng/mL. Urine samples of the elimination study with PEA yielded concentration ratios of M1/PEA up to values of 9.4. Notably, the urinary concentration of PEA did increase with the intake of PEA only to a modest extent, suggesting a comprehensive metabolism of the orally administered substance. Conversely, doping control

  14. A novel phosphonate for the repair of critical size bone defects.

    PubMed

    Bassi, Ak; Gough, Je; Downes, S

    2012-11-01

    Bone has the ability to spontaneously regenerate itself. However, the treatment of critical size bone defects can be problematic. In this study, the healing potential of critical size neonatal mouse parietal defects was evaluated using a scaffold composed of poly (ε-caprolactone) (PCL) and polyvinyl phosphonic co-acrylic acid (PVPA) (referred to as PCL/PVPA). Full thickness 1.5 mm circular defects were created in parietal bones obtained from one litter of 4-day-old CD1 mice. The bones were divided into two groups and embedded with PCL or PCL/PVPA scaffolds. The healing response was evaluated using microcomputed tomography, dissecting microscopy, phase contrast microscopy, scanning electron microscopy, and energy dispersive spectroscopy. There was a significant increase (P<0.05) in bone fill percentage in the presence of the PCL/PVPA scaffold (63.57%) compared with PCL scaffolds (29.64%). The formation of tissue and deposition of extracellular matrix was confirmed by scanning electron microscopy. There was evidence of collagen fibre deposition as well as hydroxyapatite and overall woven bone formation. PCL/PVPA scaffolds were better integrated into the defect site. The potential formation of hydroxyapatite was evaluated using energy dispersive spectroscopy. Results showed a significant increase in calcium and phosphorus levels in the presence of PCL/PVPA scaffold. Histological analysis using Masson's trichrome staining confirmed the presence of collagen above and below the PCL/PVPA scaffold within the defect site. In conclusion, this study showed that the PCL/PVPA scaffold is a novel system that has the potential for use as a bone graft substitute and in assisting in the healing of critical size defects. PMID:22034438

  15. Synthesis and herbicidal activity evaluation of novel α-amino phosphonate derivatives containing a uracil moiety.

    PubMed

    Che, Jian-yi; Xu, Xiao-yun; Tang, Zi-long; Gu, Yu-cheng; Shi, De-qing

    2016-02-15

    A series of novel α-amino phosphonate derivatives containing a uracil moiety 3a-3l were designed and synthesized by a Lewis acid (magnesium perchlorate) catalyzed the Kabachnik-Fields reaction. The bioassays {in vitro, in vivo [Glass House 1 (GH1) and Glass House 2 (GH2)]} showed that most of compounds 3 exhibited excellent and selective herbicidal activities; for example, in GH1 test, compounds 3b, 3d, 3f, 3h and 3j showed excellent and wide spectrum herbicidal activities at the dose of 1000 g/ha, and compounds 3b and 3j exhibited 100% inhibition activities against the four plants in both post- and pre-emergence treatments. Moreover, most of compounds 3 showed higher inhibition against Amaranthus retroflexus and Digitaria sanguinalis than Glyphosate did in pre-emergence treatment. In GH2 test, the four compounds (3b, 3d, 3h and 3j) exhibited 100% inhibition against Solanum nigrum, Amaranthus retroflexus and Ipomoea hederacea in post-emergence treatment and displayed 100% inhibition against Solanum nigrum, Amaranthus retroflexus in pre-emergence treatment at the rate of 250 g/ha, and compound 3b showed the best and broad spectrum herbicidal activities against the six test plants. However, the four compounds displayed weaker herbicidal activities against Lolium perenne and Echinochloa crus-galli than the other four plants at the rate of 250 g/ha in both pre- and post-emergence treatments. So, compounds 3 can be used as a lead compound for further structure optimization for developing potential selective herbicidal agent. Their preliminary structure-activity relationships were also investigated. PMID:26786699

  16. Bifunctional phenyl monophosphonic/sulfonic acid ion exchange resin and process for using the same

    DOEpatents

    Alexandratos, Spiro; Shelley, Christopher A.; Horwitz, E. Philip; Chiarizia, Renato; Gula, Michael J.; Xue, Sui; Harvey, James T.

    2002-01-01

    A cross-linked water-insoluble ion exchange resin comprised of polymerized monomers having a phenyl ring is disclosed. A contemplated resin contains (i) polymerized phenyl ring-containing monomers having a phosphonic acid ligand linked to the phenyl ring, (ii) about 2 to about 5 millimoles per gram (mmol/g) of phosphorus as phosphonic acid ligands, and (iii) a sufficient amount of a sulfonic acid ligand such that the ratio of mmol/g of phosphonic acid to mmol/g sulfonic acid is up to 3:1. A process for removing polyvalent metal cations from aqueous solution, and a process for removing iron(III) cations from acidic copper(II) cation-containing solutions that utilize the contemplated resin or other resins are disclosed.

  17. Bifunctional phenyl monophosphonic/sulfonic acid ion exchange resin and process for using the same

    DOEpatents

    Alexandratos, Spiro; Shelley, Christopher A.; Horwitz, E. Philip; Chiarizia, Renato

    2001-01-01

    A cross-linked water-insoluble ion exchange resin comprised of polymerized monomers having a phenyl ring is disclosed. A contemplated resin contains (i) polymerized phenyl ring-containing monomers having a phosphonic acid ligand linked to the phenyl ring, (ii) about 2 to about 5 millimoles per gram (mmol/g) of phosphorus as phosphonic acid ligands, and (iii) a sufficient amount of a sulfonic acid ligand such that the ratio of mmol/g of phosphonic acid to mmol/g sulfonic acid is up to 3:1. A process for removing polyvalent metal cations from aqueous solution, and a process for removing iron(III) cations from acidic copper(II) cation-containing solutions that utilize the contemplated resin or other resins are disclosed.

  18. 2-[4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy]-N-(methylsulfonyl)acetamide (NS-304), an orally available and long-acting prostacyclin receptor agonist prodrug.

    PubMed

    Kuwano, Keiichi; Hashino, Asami; Asaki, Tetsuo; Hamamoto, Taisuke; Yamada, Tetsuhiro; Okubo, Kaori; Kuwabara, Kenji

    2007-09-01

    Prostacyclin (PGI(2)) and its analogs are useful for the treatment of various vascular disorders, but their half-lives are too short for widespread clinical application. To overcome this drawback, we have synthesized a novel diphenylpyrazine derivative, 2-[4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy]-N-(methylsulfonyl)acetamide (NS-304), a prodrug of the active form [4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy]acetic acid (MRE-269). NS-304 is an orally available and potent agonist for the PGI(2) receptor (IP receptor). The inhibition constant (K(i)) of MRE-269 for the human IP receptor was 20 nM; in contrast, the K(i) values for other prostanoid receptors were >2.6 microM. MRE-269 was therefore a highly selective agonist for the IP receptor. The plasma concentrations of MRE-269 remained near peak levels for more than 8 h after oral administration of NS-304 to rats and dogs, and NS-304 increased femoral skin blood flow in rats in a long-lasting manner without affecting the hemodynamics. These findings indicate that NS-304 acts as a long-acting IP receptor agonist in vivo. The continuous vasodilation evoked by NS-304 was not attenuated by repeated treatment, indicating that NS-304 is unlikely to cause severe desensitization of the IP receptor in rats. Moreover, a microdose pharmacokinetic study in which NS-304 was orally administered to healthy male volunteers showed conversion of NS-304 to MRE-269 and a long plasma elimination half-life for MRE-269 (7.9 h). In conclusion, NS-304 is an orally available and long-acting IP receptor agonist prodrug, and its active form, MRE-269, is highly selective for the IP receptor. Therefore, NS-304 is a promising drug candidate for various vascular diseases, especially pulmonary arterial hypertension and arteriosclerosis obliterans. PMID:17545310

  19. Structure of complexes of nitrilo tris methylene phosphonic acid with copper, [CuN(CH{sub 2}PO{sub 3}){sub 3}(H{sub 2}O){sub 3}] and Na{sub 4}[CuN(CH{sub 2}PO{sub 3}){sub 3}]{sub 2} · 19H{sub 2}O, as bactericides and inhibitors of scaling and corrosion

    SciTech Connect

    Somov, N. V.; Chausov, F. F.

    2015-03-15

    Nitrilotris methylene phosphonate triaqua copper and octasodium bis(nitrilotris methylene phosphonate cuprate(II)) nonadecahydrate have been synthesized and investigated. [CuN(CH{sub 2}PO{sub 3}){sub 3}(H{sub 2}O){sub 3}] is crystallized in the sp. gr. P2{sub 1}/c, Z = 4, a = 9.2506(2) Å, b = 15.9815(2) Å, c = 9.5474(2) Å, β = 113.697(2)°. The copper atom is coordinated by oxygen atoms in the configuration of elongated octahedron; the ligand (of bridge type) links neighboring copper atoms. Na{sub 8}[CuN(CH{sub 2}PO{sub 3}){sub 3}]{sub 2} · 19H{sub 2}O is crystallized in the sp. gr. P2{sub 1}/c, Z = 2, a = 11.24550(10) Å, b = 17.38980(10) Å, c = 13.5852(2) Å, β = 127.8120(10)°. This complex is chelating; the copper atom closes three five-membered N-C-P-O-Cu cycles with a shared Cu-N bond. Copper is coordinated in a distorted trigonal-bipyramidal configuration.

  20. Current Understanding of Perfluoroalkyl Acid Toxicology

    EPA Science Inventory

    The perfluoroalkyl acids (PFAAs) are a family of organic chemicals consisting of a perfluorinated carbon backbone (4-14 carbons in length) and an anionic head group (sulfonate, carboxylate or phosphonate). These compounds have excellent surface-tension reducing properties and hav...

  1. Perfluoroalkyl acids : Recent activities and research progress

    EPA Science Inventory

    The perfluoroalkyl acids (PFAAs) are a family of man-made fluorinated organic chemicals consisting of a carbon backbone typically of four to fourteen in length and a charged functional moiety (primarily carboxylate, sulfonate or phosphonate). The two most widely known PFAAs are ...

  2. Inorganic-organic hybrid compounds: Synthesis and characterization of three new metal phosphonates with similar characteristic structural features

    SciTech Connect

    Bauer, Sebastian; Stock, Norbert . E-mail: stock@ac.uni-kiel.de

    2006-01-15

    The phosphonocarboxylic acid H(HO{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH (H{sub 5} L ) was synthesized and characterized by NMR- and IR-spectroscopy, thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Reactions of H{sub 5} L with samarium(III) chloride and calcium(II) chloride resulted in three new compounds, Sm[(O{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH].H{sub 2}O (1), Ca[H(O{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH].H{sub 2}O (2), and Ca[(HO{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH]{sub 2}.4H{sub 2}O (3). The single-crystal structure determination of the title compounds reveals that in H{sub 5} L as well as in compounds 1, 2, and 3 zwitterions are present. Within the M-O building units of the metal phosphonates we observed a different degree of dimensionality, depending on the oxidation state of the metal ion and the synthesis conditions. In 1, one-dimensional chains of edge-sharing SmO{sub 8} polyhedra are observed while in 2, isolated units of edge-sharing CaO{sub 6} octahedra and in 3 isolated CaO{sub 6} octahedra are observed. However, looking at the organic part, the rigid phenyl carboxylic acid moieties arrange in a 'zipper-like' fashion and hydrogen bonding plays an important role in the stabilization of the crystal structure. The title compounds were further characterized by IR spectroscopy and TG analysis. Additionally, the thermal stability of 1 was investigated by temperature-dependent X-ray diffraction. -- Graphical abstract: Hydrothermal reactions of the phosphonocarboxylic acid H(HO{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH with Sm{sup 3+} and Ca{sup 2+} salts has led to three new inorganic-organic hybrid compounds. All crystal structures contain phosphonate zwitterions and have a layer-like arrangement. The rigid organic groups arrange in a 'zipper-like' fashion and hydrogen bonding plays an important role in the stabilization of the crystal

  3. Understanding the mechanism of action of triazine-phosphonate derivatives as flame retardants for cotton fabrics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Countless hours of research and studies on triazine, phosphonate and their combination have provided insightful information into their flame retardant properties on polymeric systems. However, only limited number of studies shed light on the mechanism of flame retardant cotton fabrics. The purpose...

  4. A diethyl phosphonate containing oxazoline: Synthesis and characterization of monomer and homopolymer

    SciTech Connect

    Hermes, R.E.; Thompson, R.D.; Valdez, L.S.

    1995-05-01

    A diethyl phosphonate oxazoline monomer and its polymer have been synthesized. The monomer appears to polymerize via a ring-opening mechanism giving the expected polyethyleneimine backbone with pendant carbonyl groups. Two distinct molecular weights were produced during polymerization suggesting two mechanisms of chain growth. Studies are underway to elucidate the reasons for this. This polymer has potential as a metal-chelating agent.

  5. Functionalization of SBA-15 mesoporous silica by Cu-phosphonate units: Probing of synthesis route

    SciTech Connect

    Laskowski, Lukasz; Laskowska, Magdalena

    2014-12-15

    Mesoporous silica SBA-15 containing propyl-copper phosphonate units was investigated. The structure of mesoporous samples was tested by N{sub 2} isothermal sorption (BET and BHJ analysis), TEM microscopy and X-Ray scattering. Quantitative analysis EDX has given information about proportions between component atoms in the sample. Quantitative elemental analysis has been carried out to support EDX. To examine bounding between copper atoms and phosphonic units the Raman spectroscopy was carried out. As a support of Raman scattering, the theoretical calculations were made based on density functional theory, with the B3LYP method. By comparison of the calculated vibrational spectra of the molecule with experimental results, distribution of the active units inside silica matrix has been determined. - Graphical abstract: The present study is devoted to mesoporous silica SBA-15 containing propyl-copper phosphonate units. The species were investigated to confirm of synthesis procedure correctness by the micro-Raman technique combined with DFT numerical simulations. Complementary research was carried out to test the structure of mesoporous samples. - Highlights: • SBA-15 silica functionalized with propyl-copper phosphonate units was synthesized. • Synthesis efficiency probed by Raman study supported with DFT simulations. • Homogenous distribution of active units was proved. • Synthesis route enables precise control of distance between copper ions.

  6. Evaluation of phosphonate treatments for control of phytophthora crown rot of walnut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar and soil applications of phosphonate were evaluated in a factorial manner for control of trunk cankers caused by Phytophthora citricola in a Persian walnut orchard, cultivar ‘Chandler’. In each of two experiments, the foliar treatment was applied once in the second week of September, whereas...

  7. Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

    PubMed Central

    Jang, Hee Seung; Kim, Yubin

    2016-01-01

    Summary Chiral binaphthyl-modified squaramide-catalyzed enantioselective addition of diphenyl phosphonate to ketimines derived from isatins has been achieved. This method affords practical and efficient access to chiral 3-amino-3-phosphonyl-substituted oxindole derivatives in high yields with excellent enantioselectivities (up to 99% ee). PMID:27559405

  8. Seasonal Expression of the Picocyanobacterial Phosphonate Transporter Gene phnD in the Sargasso Sea.

    PubMed

    Ilikchyan, Irina N; McKay, Robert Michael L; Kutovaya, Olga A; Condon, Rob; Bullerjahn, George S

    2010-01-01

    In phosphorus-limited marine environments, picocyanobacteria (Synechococcus and Prochlorococcus spp.) can hydrolyze naturally occurring phosphonates as a P source. Utilization of 2-aminoethylphosphonate (2-AEP) is dependent on expression of the phn genes, encoding functions required for uptake, and C-P bond cleavage. Prior work has indicated that expression of picocyanobacterial phnD, encoding the phosphonate binding protein of the phosphonate ABC transporter, is a proxy for the assimilation of phosphonates in natural assemblages of Synechococcus spp. and Prochlorococcus spp (Ilikchyan et al., 2009). In this study, we expand this work to assess seasonal phnD expression in the Sargasso Sea. By RT-PCR, our data confirm that phnD expression is constitutive for the Prochlorococcus spp. detected, but in Synechococcus spp. phnD transcription follows patterns of phosphorus availability in the mixed layer. Specifically, our data suggest that phnD is repressed in the spring when P is bioavailable following deep winter mixing. In the fall, phnD expression follows a depth-dependent pattern reflecting depleted P at the surface following summertime drawdown, and elevated P at depth. PMID:21687717

  9. Hydrogen-Bond Basic Siloxane Phosphonate Polymers for Surface Acoustic Wave (Saw) Sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A surface acoustic wave (SAW) sensor coated with a novel hydrogen-bond basic siloxane phosphonate SAW polymer gave excellent initial response and long-term performance when tested against phenol vapor and compared with polyethyleneimine (PEI), a conventional hydrogent-bond basic SAW polymer....

  10. Thermal decomposition reactions of cotton fabric treated with piperazine-phosphonates derivatives as a flame retardant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been a great scientific interest in exploring the great potential of the piperazine-phosphonates in flame retardant (FR) application on cotton fabric by investigating the thermal decomposition of cotton fabric treated with them. This research tries to understand the mode of action of the t...

  11. Synthesis of phosphonate analogues of the antiviral cyclopropane nucleoside A-5021.

    PubMed

    Onishi, Tomoyuki; Sekiyama, Takaaki; Tsuji, Takashi

    2005-01-01

    A series of phosphonate analogues of the antiviral cyclopropane nucleoside A-5021 were synthesized from (1S*, 7R*)-3,5-dioxa-4,4-diphenylbicyclo[5. 1.0]octane-l-methanol by a 10-step process. In contrast to the potent antiherpetic activity of A-5021, they were all devoid of antiviral activity. PMID:16270661

  12. Comparison of Zirconium Phosphonate-Modified Surfaces for Immobilizing Phosphopeptides and Phosphate-Tagged Proteins.

    PubMed

    Forato, Florian; Liu, Hao; Benoit, Roland; Fayon, Franck; Charlier, Cathy; Fateh, Amina; Defontaine, Alain; Tellier, Charles; Talham, Daniel R; Queffélec, Clémence; Bujoli, Bruno

    2016-06-01

    Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr(4+), afforded better immobilization of the peptides and proteins and efficient capture of their targets. PMID:27166821

  13. The mechanism of action of piperazine-phosphonates derivatives in cotton fabric

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Piperazine-phosphonates additives are known to be very effective flame retardants on different polymeric systems, especially cotton cellulose. In order to understand their mechanism of action, we carried out the investigation of their thermal behavior on cotton fabric by, first, employing the attenu...

  14. Collective dynamic dipole moment and orientation fluctuations, cooperative hydrogen bond relaxations, and their connections to dielectric relaxation in ionic acetamide deep eutectics: Microscopic insight from simulations.

    PubMed

    Das, Suman; Biswas, Ranjit; Mukherjee, Biswaroop

    2016-08-28

    The paper reports a detailed simulation study on collective reorientational relaxation, cooperative hydrogen bond (H-bond) fluctuations, and their connections to dielectric relaxation (DR) in deep eutectic solvents made of acetamide and three uni-univalent electrolytes, lithium nitrate (LiNO3), lithium bromide (LiBr), and lithium perchlorate (LiClO4). Because cooperative H-bond fluctuations and ion migration complicate the straightforward interpretation of measured DR timescales in terms of molecular dipolar rotations for these conducting media which support extensive intra- and inter-species H-bonding, one needs to separate out the individual components from the overall relaxation for examining the microscopic origin of various timescales. The present study does so and finds that reorientation of ion-complexed acetamide molecules generates relaxation timescales that are in sub-nanosecond to nanosecond range. This explains in molecular terms the nanosecond timescales reported by recent giga-Hertz DR measurements. Interestingly, the simulated survival timescale for the acetamide-Li(+) complex has been found to be a few tens of nanosecond, suggesting such a cation-complexed species may be responsible for a similar timescale reported by mega-Hertz DR measurements of acetamide/potassium thiocyanate deep eutectics near room temperature. The issue of collective versus single particle relaxation is discussed, and jump waiting time distributions are determined. Dependence on anion-identity in each of the cases has been examined. In short, the present study demonstrates that assumption of nano-sized domain formation is not required for explaining the DR detected nanosecond and longer timescales in these media. PMID:27586932

  15. Phosphonate fertilizers suppressed root knot nematodes Meloidogyne javanica and M. incognita

    PubMed Central

    Habash, Samer; Al-Banna, Luma

    2011-01-01

    The efficacy of the phosphonate fertilizers, Calphos® (a.i. calcium phosphonate), Magphos® (a.i. magnesium phosphonate and potassium phosphonate) and Phosphoros® (a.i. potassium phosphonate) against two species of root knot nematodes (RKN), Meloidogyne javanica and M. incognita is evaluated. Laboratory experiments showed that Calphos®, Magphos® and their main components inhibited egg hatching and caused 100% mortality of the second stage juveniles (J2s) of the two RKN species; the hatching inhibition effects persisted after transferring the egg masses of both species to water. However, Phosphoros® (0.5%) did not suppress egg hatching or the survival of J2s of both RKN species. No hatching occurred when egg masses were treated for one week with the nematicide Vydate L® (2 ml/l), however, J2s hatched when the Vydate L® treated egg masses were moved to water. The glasshouse study indicated that Magphos®, Calphos® and Phosphoros® reduced root galling caused by M. javanica by 98, 66 and 47%, respectively, in comparison to the untreated controls. Magphos® resulted in the lowest number of root galls formed by M. incognita, the reduction was 84%. In contrast, Calphos® and Phosphoros® reduced galling by 47 and 39%, respectively. The Magphos® treatment resulted in the lowest numbers of egg masses and the lowest reproductive factor (RF) of both nematode species. However, plants treated with Phosphoros® resulted in higher foliage weights compared with the application of the other two fertilizers and the untreated plants. PMID:22791918

  16. Synthesis and characterization of calcium hydroxy and fluoroapatite functionalized with methyl phosphonic dichloride

    NASA Astrophysics Data System (ADS)

    Agougui, Hassen; Aissa, Abdallah; Debbabi, Mongi

    2012-11-01

    The nature of apatite-organic molecule interaction was the subject of many investigations. Grafting the organic molecule onto the inorganic support may precede through either formation of covalent bonds or ionic interaction between superficial hydroxyl on the apatite surface and organic functions. The hybrid materials obtained by functionalization of apatite surfaces with phosphonate moieties are of interest for their potential applications such in catalysis, chromatography and biomedical domain. In this scope, calcium hydroxyl and fluoroapatite (CaHAp and CaFAp) were prepared in the presence of the methyl phosphonic dichloride (MPO), by contact method in organic solvent at 25 °C for 2 days. The products are rigorously characterized by chemical analysis, infrared (IR), MAS-NMR spectroscopies, powder X-ray diffraction (XRD), atomic force microscopy (AFM) and specific surface area (SSA). The X-ray powder analysis showed that the crystallinity was sensibly affected by the presence of organic moieties. The IR spectroscopy showed new vibration modes appearing related to phosphonate groups essentially at 2930, 1315, 945, 764 and 514 cm-1. The 31P MAS NMR spectrum for hydroxy and fluoroapatite exhibits a single signal at 2.8 ppm. After reaction with (MPO) the spectra show the presence of new signals, assigned to the formation of organic-inorganic bond between the superficial hydroxyl groups of the apatite (tbnd CaOH) and (tbnd POH) and methyl phosphonic dichloride. The SSA decreases with increasing phosphonate amount especially for CaHAp modified by (MPO). AFM indicated that the texture surface was changed by grafting.

  17. The Genes and Enzymes of Phosphonate Metabolism by Bacteria, and Their Distribution in the Marine Environment

    PubMed Central

    Villarreal-Chiu, Juan F.; Quinn, John P.; McGrath, John W.

    2011-01-01

    Phosphonates are compounds that contain the chemically stable carbon–phosphorus (C–P) bond. They are widely distributed amongst more primitive life forms including many marine invertebrates and constitute a significant component of the dissolved organic phosphorus reservoir in the oceans. Virtually all biogenic C–P compounds are synthesized by a pathway in which the key step is the intramolecular rearrangement of phosphoenolpyruvate to phosphonopyruvate. However C–P bond cleavage by degradative microorganisms is catalyzed by a number of enzymes – C–P lyases, C–P hydrolases, and others of as-yet-uncharacterized mechanism. Expression of some of the pathways of phosphonate catabolism is controlled by ambient levels of inorganic P (Pi) but for others it is Pi-independent. In this report we review the enzymology of C–P bond metabolism in bacteria, and also present the results of an in silico investigation of the distribution of the genes that encode the pathways responsible, in both bacterial genomes and in marine metagenomic libraries, and their likely modes of regulation. Interrogation of currently available whole-genome bacterial sequences indicates that some 10% contain genes encoding putative pathways of phosphonate biosynthesis while ∼40% encode one or more pathways of phosphonate catabolism. Analysis of metagenomic data from the global ocean survey suggests that some 10 and 30%, respectively, of bacterial genomes across the sites sampled encode these pathways. Catabolic routes involving phosphonoacetate hydrolase, C–P lyase(s), and an uncharacterized 2-aminoethylphosphonate degradative sequence were predominant, and it is likely that both substrate-inducible and Pi-repressible mechanisms are involved in their regulation. The data we present indicate the likely importance of phosphonate-P in global biogeochemical P cycling, and by extension its role in marine productivity and in carbon and nitrogen dynamics in the oceans. PMID:22303297

  18. Fluorescence spectroscopic studies of (acetamide + sodium/potassium thiocyanates) molten mixtures: composition and temperature dependence.

    PubMed

    Guchhait, Biswajit; Gazi, Harun Al Rasid; Kashyap, Hemant K; Biswas, Ranjit

    2010-04-22

    Steady state and time-resolved fluorescence spectroscopic techniques have been used to explore the Stokes' shift dynamics and rotational relaxation of a dipolar solute probe in molten mixtures of acetamide (CH(3)CONH(2)) with sodium and potassium thiocyanates (Na /KSCN) at T approximately 318 K and several other higher temperatures. The dipolar solute probe employed for this study is coumarin 153 (C153). Six different fractions (f) of KSCN of the following ternary mixture composition, 0.75 CH(3)CONH(2) + 0.25[(1 - f)NaSCN + fKSCN], have been considered. The estimated experimental dynamic Stokes' shift for these systems ranges between 1800 and 2200 cm(-1) (+/-250 cm(-1)), which is similar to what has been observed with the same solute probe in several imidazolium cation based room temperature ionic liquids (RTIL) and in pure amide solvents. Interestingly, this range of estimated Stokes' shift, even though not corresponding to the megavalue of static dielectric constant reported in the literature for a binary mixture of molten CH(3)CONH(2) and NaSCN, exhibits a nonmonotonic KSCN concentration dependence. The magnitudes of the dynamic Stokes' shift detected in the present experiments are significantly less than the estimated ones, as nearly 40-60% of the total shift is missed due to the limited time resolution employed (full-width at half-maximum of the instrument response function approximately 70 ps). The solvation response function, constructed from the detected shifts in these systems, exhibits triexponential decay with the fastest time constant (tau(1)) in the 10-20 ps range, which might be much shorter if measured with a better time resolution. The second time constant (tau(2)) lies in the 70-100 ps range, and the third one (tau(3)) ranges between 300 and 800 ps. Both these time constants (tau(2) and tau(3)) show alkali metal ion concentration dependence and exhibit viscosity decoupling at higher viscosity in the NaSCN-enriched region. Time dependent rotational

  19. Synthesis and Evaluation of Novel Acyclic Nucleoside Phosphonates as Inhibitors of Plasmodium falciparum and Human 6-Oxopurine Phosphoribosyltransferases.

    PubMed

    Kaiser, Martin M; Hocková, Dana; Wang, Tzu-Hsuan; Dračínský, Martin; Poštová-Slavětínská, Lenka; Procházková, Eliška; Edstein, Michael D; Chavchich, Marina; Keough, Dianne T; Guddat, Luke W; Janeba, Zlatko

    2015-10-01

    Acyclic nucleoside phosphonates (ANPs) are a promising class of antimalarial therapeutic drug leads that exhibit a wide variety of Ki values for Plasmodium falciparum (Pf) and human hypoxanthine-guanine-(xanthine) phosphoribosyltransferases [HG(X)PRTs]. A novel series of ANPs, analogues of previously reported 2-(phosphonoethoxy)ethyl (PEE) and (R,S)-3-hydroxy-2-(phosphonomethoxy)propyl (HPMP) derivatives, were designed and synthesized to evaluate their ability to act as inhibitors of these enzymes and to extend our ongoing antimalarial structure-activity relationship studies. In this series, (S)-3-hydroxy-2-(phosphonoethoxy)propyl (HPEP), (S)-2-(phosphonomethoxy)propanoic acid (CPME), or (S)-2-(phosphonoethoxy)propanoic acid (CPEE) are the acyclic moieties. Of this group, (S)-3-hydroxy-2-(phosphonoethoxy)propylguanine (HPEPG) exhibits the highest potency for PfHGXPRT, with a Ki value of 0.1 μM and a Ki value for human HGPRT of 0.6 μM. The crystal structures of HPEPG and HPEPHx (where Hx=hypoxanthine) in complex with human HGPRT were obtained, showing specific interactions with active site residues. Prodrugs for the HPEP and CPEE analogues were synthesized and tested for in vitro antimalarial activity. The lowest IC50 value (22 μM) in a chloroquine-resistant strain was observed for the bis-amidate prodrug of HPEPG. PMID:26368337

  20. A (Fluoroalkyl)Guanidine Modulates the Relaxivity of a Phosphonate-Containing T 1-Shortening Contrast Agent.

    PubMed

    Wu, Xinping; Dawsey, Anna C; Siriwardena-Mahanama, Buddhima N; Allen, Matthew J; Williams, Travis J

    2014-12-01

    Responsive magnetic resonance imaging (MRI) contrast agents, those that change their relaxivity according to environmental stimuli, have promise as next generation imaging probes in medicine. While several of these are known based on covalent modification of the contrast agents, fewer are known based on controlling non-covalent interactions. We demonstrate here accentuated relaxivity of a T 1-shortening contrast agent, Gd-DOTP(5-) based on non-covalent, hydrogen bonding of Gd-DOTP(5-) with a novel fluorous amphiphile. By contrast to the phosphonate-containing Gd-DOTP(5-) system, the relaxivity of the analogous clinically approved contrast agent, Gd-DOTA(-) is unaffected by the same fluorous amphiphile under similar conditions. Mechanistic studies show that placing the fluorous amphiphile in proximity of the gadolinium center in Gd-DOTP(5-) caused an increase in τ m (bound-water residence lifetime or the inverse of water exchange rate, τ m = 1/k ex) and an increase in τ R (rotational correlation time), with τ R being the factor driving enhanced relaxivity. Further, these effects were not observed when Gd-DOTA(-) was treated with the same fluorous amphiphile. Thus, Gd-DOTP(5-) and Gd-DOTA(-) respond to the fluorous amphiphile differently, presumably because the former binds to the amphiphile with higher affinity. (DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraphosphonic acid; DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). PMID:25431503

  1. Comparison of the crystal structure and molecular models of N,N-dissobutyl-2-(octylphenylphosphinyl)acetamide(CMPO).

    SciTech Connect

    Rogers, R. D.; Rollins, A. N.; Gatrone, R. C.; Horwitz, E. P.; Chemistry; Northern Illinois Univ.

    1995-01-01

    The crystal structure of N,N-diisobutyl-2-(octylphenylphosphinyl)acetamide, or CMPO was recently determined. The compound crystallizes in the space group P2{sub 1}/c with a=13.446(6),b=22.280(7),c=17.217(7) Angstroms, {beta}=92.07(4) degrees, and D{sub calc}=1.05 g/cm3 for Z=8 @20 C. Molecular mechanics, molecular dynamics, and MNDO calculations were also performed on CMPO utilizing the SYBYL suite of programs. The results from these calculations are compared to the crystal structure and to similar calculations performed on CMPO using ALCHEMY. In general, the results from the calculations agree fairly well with the parameters from the crystal structure.

  2. Synthesis, potential anticonvulsant and antidepressant effects of 2-(5-methyl-2,3-dioxoindolin-1-yl)acetamide derivatives.

    PubMed

    Zhen, Xinghua; Peng, Zhou; Zhao, Shuilian; Han, Yan; Jin, Qinghao; Guan, Liping

    2015-07-01

    A new series of 2-(5-methyl-2,3-dioxoindolin-1-yl)acetamide derivatives were synthesized and evaluated for their anticonvulsive activity in a pentylenetetrazole (PTZ)-evoked convulsion model and antidepressant activity in the forced swimming test (FST) model. Eleven synthesized compounds were found to be protective against PTZ-induced seizure and showed the anticonvulsant activity. In addition, four of the synthesized compounds (4l, 4m, 4p and 4q) showed potent antidepressant-like activity. Among these compounds, compound 4l was found to have the most potent antidepressant-like activity, and significantly reduced the duration of immobility time at 100 mg/kg dose level when compared to the vehicle control, which is similar to the reference drug fluoxetine. PMID:26579465

  3. Design, synthesis and in vitro evaluation studies of sulfonyl-amino-acetamides as small molecule BACE-1 inhibitors.

    PubMed

    Jain, Priti; Wadhwa, Pankaj K; Gunapati, Sinduri; Jadhav, Hemant R

    2016-06-01

    The identification of a series of sulfonyl-amino-acetamides as BACE-1 (β-secretase) inhibitors for the treatment of Alzheimer's disease is reported. The derivatives were designed based on the docking simulation study, synthesized and assessed for BACE-1 inhibition in vitro. The designed ligands revealed desired binding interactions with the catalytic aspartate dyad and occupance of S1 and S2' active site regions. These in silico results correlated well with in vitro activity. Out of 33 compounds synthesized, 12 compounds showed significant inhibition at 10μM concentration. The most active compound 2.17S had IC50 of 7.90μM against BACE-1, which was concomitant with results of in silico docking study. PMID:27102162

  4. 2-Chloro-N-[4-chloro-2-(2-chloro­benzo­yl)phen­yl]acetamide

    PubMed Central

    Dutkiewicz, Grzegorz; Siddaraju, B. P.; Yathirajan, H. S.; Narayana, B.; Kubicki, Maciej

    2010-01-01

    In the title compound, C15H10Cl3NO2, an intra­molecular N—H⋯O hydrogen bond forms a six-membered ring and enforces an almost coplanar conformation for the acetamido group, the central benzene ring and the bridging carbonyl C—C(=O)—C group: the dihedral angles between the benzene ring and the acetamide and carbonyl C—C(=O)—C planes are 7.06 (11) and 7.17 (12)°, respectively. The dihedral angle between the two benzene rings is 67.43 (9)°. Because a strong hydrogen-bond donor is involved in the intra­molecular inter­action, the crystal packing is determined by weak C—H⋯O and C—H⋯Cl inter­actions. PMID:21579901

  5. Click-based synthesis and antitubercular evaluation of dibenzofuran tethered thiazolyl-1,2,3-triazolyl acetamides.

    PubMed

    Surineni, Goverdhan; Yogeeswari, Perumal; Sriram, Dharmarajan; Kantevari, Srinivas

    2016-08-01

    A series of novel dibenzofuran tethered thiazolyl-1,2,3-triazolyl acetamides, designed by assembling antitubercular pharmacophoric fragments, dibenzofuran, 2-aminothiazole and substituted triazoles in one molecular architecture, were evaluated against Mycobacterium tuberculosis. The new analogues 6a-p accomplished in four step synthetic sequence utilizing click chemistry in the penultimate step, was fully characterized by their NMR and mass spectral data. Among the compounds 6a-p screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv, three compounds 6j (MIC: 1.56μg/mL); 6a and 6p (MIC: 3.13μg/mL) was found to be most active and exhibited lower cytotoxicity. Among these three, 6j could be a candidate to consider as a drug like hit analogue for further development. PMID:27317646

  6. Use of new phosphonylating and coupling agents in the synthesis of oligodeoxyribonucleotides via the H-phosphonate approach.

    PubMed Central

    Sakatsume, O; Yamane, H; Takaku, H; Yamamoto, N

    1990-01-01

    New phosphonylating and coupling agents for the synthesis of oligodeoxyribonucleotides via H-phosphonate approach have been developed. Tris(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite, prepared by the reaction of lithium salt of 1,1,1,3,3,3-hexafluoro-2-propoxide with PCl3, reacts with deoxyribonucleosides in the presence of a catalytic amount of triethylamine to produce in the high yield the corresponding deoxyribonucleoside 3'-H-phosphonate units. The use of a new coupling reagent, 1,3-dimethyl-2-chloro-imidazolinium chloride (DMCI) for the internucleotidic H-phosphonate bond formation via the H-phosphonate approach is also discussed in detail. Images PMID:2356122

  7. Effect of phosphonate monolayer adsorbate on the microwave photoresponse of TiO2 nanotube membranes mounted on a planar double ring resonator

    NASA Astrophysics Data System (ADS)

    Zarifi, Mohammad H.; Farsinezhad, Samira; Wiltshire, Benjamin D.; Abdorrazaghi, Mohammad; Mahdi, Najia; Kar, Piyush; Daneshmand, Mojgan; Shankar, Karthik

    2016-09-01

    In this study, the effects of a phosphonate molecular monolayer adsorbed on the surface of a free-standing self-organized TiO2 nanotube membrane, on the microwave photoresponse of the membrane are presented. This phenomenon is monitored using planar microwave sensors. A double ring resonator is utilized to monitor the permittivity and conductivity variation on the monolayer coated membrane and the sensor environment separately. It is shown that the rise time and subsequent decay of the amplitude (A), resonance frequency (f 0) and quality factor (Q) of the resonator depend on the existence and the type of the monolayer coating the membrane. Three different monolayers of n-decylphosphonic acid (DPA), 1H, 1H‧, 2H, 2H‧-perfluorodecyl phosphonic acid (PFDPA) and 16-phosphonohexadecanoic acid adsorbed on the titania nanotube membrane are investigated while monitoring their microwave properties during the illumination time period and in the relaxation period, which demonstrate different behavior in comparison to each other and to the bare nanotube membrane layer. The effect of humidity on the TiO2 nanotube membrane with and without different monolayers is also studied and the results demonstrate distinguishable microwave responses. While each of the monolayer-coated membranes exhibited an attenuation of the photo-induced change in A, f 0 and Q with respect to the bare membrane, PFDPA-coated membranes showed the smallest relative change in the monitored microwave parameters upon ultraviolet illumination and upon the introduction of different levels of humidity. These effects are explained on the basis of surface trap passivation by the monolayers as well as the hydrophobicity of the monolayers. Our work also shows how the interactions of self-assembled monolayers with charge carriers and surface states on metal oxides may be used to indirectly sense their presence through measurement of the microwave response.

  8. Mesoporous zirconium titanium oxides. Part 3. Synthesis and adsorption properties of unfunctionalized and phosphonate-functionalized hierarchical polyacrylonitrile-F-127-templated beads.

    PubMed

    Sizgek, G Devlet; Griffith, Christopher S; Sizgek, Erden; Luca, Vittorio

    2009-10-01

    A method is presented for the preparation of zirconium titanate mixed oxides in bead form having hierarchical pore structure. This method entailed the use of both preformed polyacrylonitrile (PAN) polymer beads and surfactants as templates. The templates were removed by calcination at temperatures below about 500 degrees C, resulting in mixed oxide beads with trimodal pore size distributions and interconnected pores. The pore size distributions as determined using nitrogen adsorption-desorption showed clear maxima at 4.5 and 45 nm length scales and also clear evidence of microporosity. The macroporous framework morphology was a replica of the PAN beads with radial structure. The mesoporous framework possessed wormhole-like pores with pore size of about 6 nm that was consistent with the F-127 triblock copolymer template used. The mixed oxide beads exhibited surface areas of 215 and 185 m2/g after calcination at 500 and 600 degrees C. Thermal stability up to 650 degrees C is unprecedented for bulk systems. The adsorption properties were characterized using uranyl as the target cation and the mass transport in the beads with the present hierarchical architectures has been shown to be exceptional. The beads were functionalized with 4-amino,1-hydroxy,1,1-bis-phosphonic acid (HABDP) and amino-tris-methylene phosphonic acid (ATMP) and the adsorption properties for the extraction of uranyl sulfate complexes from acidic solution examined. Of the two molecules investigated, ATMP functionalization resulted in the best extraction efficiency with equilibrium uptake of about 90% of uranium available in solution between pH 1 and 2. The beads could potentially be utilized as catalysts, catalyst supports, adsorbents, and separation materials. PMID:19746937

  9. Effect of phosphonate monolayer adsorbate on the microwave photoresponse of TiO2 nanotube membranes mounted on a planar double ring resonator.

    PubMed

    Zarifi, Mohammad H; Farsinezhad, Samira; Wiltshire, Benjamin D; Abdorrazaghi, Mohammad; Najia Mahdi; Kar, Piyush; Daneshmand, Mojgan; Shankar, Karthik

    2016-09-16

    In this study, the effects of a phosphonate molecular monolayer adsorbed on the surface of a free-standing self-organized TiO2 nanotube membrane, on the microwave photoresponse of the membrane are presented. This phenomenon is monitored using planar microwave sensors. A double ring resonator is utilized to monitor the permittivity and conductivity variation on the monolayer coated membrane and the sensor environment separately. It is shown that the rise time and subsequent decay of the amplitude (A), resonance frequency (f 0) and quality factor (Q) of the resonator depend on the existence and the type of the monolayer coating the membrane. Three different monolayers of n-decylphosphonic acid (DPA), 1H, 1H', 2H, 2H'-perfluorodecyl phosphonic acid (PFDPA) and 16-phosphonohexadecanoic acid adsorbed on the titania nanotube membrane are investigated while monitoring their microwave properties during the illumination time period and in the relaxation period, which demonstrate different behavior in comparison to each other and to the bare nanotube membrane layer. The effect of humidity on the TiO2 nanotube membrane with and without different monolayers is also studied and the results demonstrate distinguishable microwave responses. While each of the monolayer-coated membranes exhibited an attenuation of the photo-induced change in A, f 0 and Q with respect to the bare membrane, PFDPA-coated membranes showed the smallest relative change in the monitored microwave parameters upon ultraviolet illumination and upon the introduction of different levels of humidity. These effects are explained on the basis of surface trap passivation by the monolayers as well as the hydrophobicity of the monolayers. Our work also shows how the interactions of self-assembled monolayers with charge carriers and surface states on metal oxides may be used to indirectly sense their presence through measurement of the microwave response. PMID:27487465

  10. Synthesis and Structure-Activity Relationships of Pyridoxal-6-arylazo-5′-phosphate and Phosphonate Derivatives as P2 Receptor Antagonists

    PubMed Central

    Kim, Yong-Chul; Camaioni, Emidio; Ziganshin, Airat U.; Ji, Xiao-duo; King, Brian F.; Wildman, Scott S.; Rychkov, Alexei; Yoburn, Joshua; Kim, Heaok; Mohanram, Arvind; Harden, T. Kendall; Boyer, José L.; Burnstock, Geoffrey; Jacobson, Kenneth A.

    2012-01-01

    Novel analogs of the P2 receptor antagonist pyridoxal-5′-phosphate-6-phenylazo-2′,4′-disulfonate (PPADS) were synthesized. Modifications were made through functional group substitution on the sulfophenyl ring and at the phosphate moiety through the inclusion of phosphonates, demonstrating that a phosphate linkage is not required for P2 receptor antagonism. Substituted 6-phenylazo and 6-naphthylazo derivatives were also evaluated. Among the 6-phenylazo derivatives, 5′-methyl, ethyl, propyl, vinyl, and allyl phosphonates were included. The compounds were tested as antagonists at turkey erythrocyte and guinea-pig taenia coli P2Y1 receptors, in guinea-pig vas deferens and bladder P2X1 receptors, and in ion flux experiments by using recombinant rat P2X2 receptors expressed in Xenopus oocytes. Competitive binding assay at human P2X1 receptors in differentiated HL-60 cell membranes was carried out by using [35S]ATP-γ-S. A 2′-chloro-5′-sulfo analog of PPADS (C14H12O9N3ClPSNa), a vinyl phosphonate derivative (C15H12O11N3PS2Na3), and a naphthylazo derivative (C18H14O12N3PS2Na2), were particularly potent in binding to human P2X1 receptors. The potencies of phosphate derivatives at P2Y1 receptors were generally similar to PPADS itself, except for the p-carboxyphenylazo phosphate derivative C15H13O8N3PNa and its m-chloro analog C15H12O8N3ClPNa, which were selective for P2X vs. P2Y1 receptors. C15H12O8N3ClPNa was very potent at rat P2X2 receptors with an IC50 value of 0.82 μM. Among the phosphonate derivatives, [4-formyl-3-hydroxy-2-methyl-6-(2-chloro-5-sulfonylphenylazo)-pyrid-5-yl]methylphosphonic acid (C14H12-O8N3ClPSNa) showed high potency at P2Y1 receptors with an IC50 of 7.23 μM. The corresponding 2,5-disulfonylphenyl derivative was nearly inactive at turkey erythrocyte P2Y1 receptors, whereas at recombinant P2X2 receptors had an IC50 value of 1.1 μM. An ethyl phosphonate derivative (C15H15O11N3PS2Na3), whereas inactive at turkey erythrocyte P2Y1 receptors

  11. Synthesis, structure, magnetism and nuclease activity of tetranuclear copper(II) phosphonates contatining ancillary 2,2'-bipyridine or 1,10-phenanthroline ligands

    SciTech Connect

    Chandrasekhar, V.; Azhakar, R.; Senapati, T.; Thilagar, P.; Gosh, S.; Verma, S.; Boomishankar, R.; Steiner, A.; Kogerler, P.

    2008-01-07

    The reaction of cyclohexylphosphonic acid (C{sub 6}H{sub 11}PO{sub 3}H{sub 2}), anhydrous CuCl{sub 2} and 2,2{prime}-bipyridine (bpy) in the presence of triethylamine followed by a metathesis reaction with KNO{sub 3} afforded [Cu{sub 4}({micro}-Cl){sub 2}({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(bpy){sub 4}](NO{sub 3}){sub 2} (1). In an analogous reaction involving Cu(OAc){sub 2} {center_dot} H{sub 2}O, the complex [Cu{sub 4}({micro}-CH{sub 3}COO){sub 2}({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(2,2-bpy){sub 4}](CH{sub 3}COO){sub 2} (2) has been isolated. The three-component reaction involving Cu(NO{sub 3}){sub 2} {center_dot} 3H{sub 2}O, cyclohexylphosphonic acid and 2,2{prime}-bipyridine in the presence of triethylamine afforded the tetranuclear assembly [Cu{sub 4}({micro}-OH)({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(2,2{prime}-bpy){sub 4} (H{sub 2}O){sub 2}](NO{sub 3}){sub 3} (3). Replacing 2,2{prime}-bipyridine with 1,10-phenanthroline (phen) in the above reaction resulted in [Cu{sub 4}({micro}-OH)({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(phen){sub 4}(H{sub 2}O){sub 2}](NO{sub 3}){sub 3} (4). In all the copper(II) phosphonates (1-4) the two phosphonate ions bridge the four copper(II) ions in a capping coordination action. Each phosphonate ion bridges four copper(II) ions in a {micro}{sub 4}, coordination mode or 4.211 of the Harris notation. Variable-temperature magnetic studies on 1-4 reveal that all four complexes exhibit moderately strong intramolecular antiferromagnetic coupling. The DNA cleavage activity of complexes 1-4 is also described. Compounds 1 and 3 were able to completely convert the supercoiled pBR322 DNA form I to nick form II without any co-oxidant. In contrast, 50% conversion occurred with 2 and 40% with 4. In the presence of magnesium monoperoxyphthalate all four compounds achieved rapid conversion of form I to form II.

  12. Stability of phosphonic self assembled monolayers (SAMs) on cobalt chromium (Co-Cr) alloy under oxidative conditions

    NASA Astrophysics Data System (ADS)

    Bhure, Rahul; Abdel-Fattah, Tarek M.; Bonner, Carl; Hall, Felicia; Mahapatro, Anil

    2011-04-01

    Cobalt chromium (Co-Cr) alloys have been widely used in the biomedical arena for cardiovascular, orthopedic and dental applications. Surface modification of the alloy allows us to tailor the interfacial properties to address critical challenges of Co-Cr alloy in medical applications. Self assembled monolayers (SAMs) of Octadecylphosphonic acid (ODPA) have been used to form thin films on the oxide layer of the Co-Cr alloy surface by solution deposition technique. The SAMs formed were investigated for their stability to oxidative conditions of ambient laboratory environment over periods of 1, 3, 7 and 14 days. The samples were then characterized for their stability using X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and contact angle measurements. Detailed high energy XPS elemental scans confirmed the presence of the phosphonic monolayer after oxidative exposure which suggested that the SAMs were firmly attached to the oxide layer of Co-Cr alloy. AFM images gave topographical data of the surface and showed islands of SAMs on Co-Cr alloy surface, before and after SAM formation and also over the duration of the oxidative exposure. Contact angle measurements confirmed the hydrophobicity of the surface over 14 days. Thus the SAMs were found to be stable for the duration of the study. These SAMs could be subsequently tailored by modifying the terminal functional groups and could be used for various potential biomedical applications such as drug delivery, biocompatibility and tissue integration.

  13. Synthesis and Biological Activity Evaluation of Novel α-Amino Phosphonate Derivatives Containing a Pyrimidinyl Moiety as Potential Herbicidal Agents.

    PubMed

    Chen, Jin-Long; Tang, Wu; Che, Jian-Yi; Chen, Kai; Yan, Gang; Gu, Yu-Cheng; Shi, De-Qing

    2015-08-19

    To find novel high-activity and low-toxicity herbicide lead compounds with novel herbicidal mode of action, series of novel α-amino phosphonate derivatives containing a pyrimidinyl moiety, I, II, III, and IV, were designed and synthesized by Lewis acid (magnesium perchlorate) catalyzed Mannich-type reaction of aldehydes, amines, and phosphites. Their structures were clearly identified by spectroscopy data (IR, (1)H NMR, (31)P NMR, EI-MS) and elemental analyses. The bioassay [in vitro, in vivo (GH1 and GH2)] showed that most compounds I exhibited good herbicidal activities; for example, the activities of compounds Ib, Ic, Ig, Ii, Ik, and Im were as good as the positive control herbicides (acetochlor, atrazine, mesotrione, and glyphosate). However, their structural isomers II and III and analogues IV did not display any herbicidal activities in vivo, although some of them possessed selective inhibitory activity against Arabidopsis thaliana in vitro. Interestingly, it was found that compounds IVs, IVt, and IVl showed selective insecticidal activities against Aphis species or Plutella xylostella, respectively. Their preliminary herbicidal mode of action and structure-activity relationships were also studied. PMID:26222653

  14. The use of phosphonates for constructing 3d-4f clusters at high oxidation states: synthesis and characterization of two unusual heterometallic CeMn complexes.

    PubMed

    Wang, Mei; Yuan, Da-Qiang; Ma, Cheng-Bing; Yuan, Ming-Jian; Hu, Ming-Qiang; Li, Na; Chen, Hui; Chen, Chang-Neng; Liu, Qiu-Tian

    2010-08-21

    The use of phosphonic acids in the synthesis of mixed-metal CeMn complexes has led to the formation of two phosphonate complexes with unusual topologies: [Ce(2)Mn(6)O(6)(OH)(5)(t-BuPO(3))(6)(O(2)CMe)(3)] x 53 H(2)O (1 x 53 H(2)O) and [Ce(22)Mn(12)O(34)(MePO(3))(12)(O(2)CMe)(33)(OMe)(6)(NO(3))(H(2)O)(12)](n) (2). The two mixed-metal CeMn complexes were both prepared from a reaction system containing Mn(O(2)CMe)(2) and (NH(4))(2)[Ce(NO(3))(6)] with similar procedures except for using different phosphonic acids (tert-butylphosphonic acid and methylphosphonic acid, respectively) as coligands. Both complexes possess rare topology of triangular type, with compound 1 being a 0D discrete cluster, whereas, compound 2 is a 1D polymer. The octanuclear core of complex 1 is composed of three symmetry equivalent distorted cubanes {Ce(IV)(2)Mn(IV)(2)O(2)(OH)(2)} sharing a trigonal-bipyramidal unit {Ce(IV)(2)(OH)(3)} in the centre. Compound 2 is a one-dimensional chain polymer of identical Ce(22)Mn(12)O(34) units linked together by NO(3)(-) and MeCO(2)(-) groups, while the Ce(22)Mn(12)O(34) unit is constituted by two centrosymmetric Ce(9)(IV)Ce(2)(III)Mn(IV)(6)O(17) subunits, which features three identical distorted cubanes {Ce(IV)(2)Mn(IV)(2)O(4)} connecting to a central trigonal-bipyramidal unit {Ce(IV)(3)O(2)}, and two additional Ce(III) ions capping the top and bottom of the central trigonal bipyramid by six MePO(3)(2-) ligands. Complexes 1 and 2 are the first high-nuclearity Mn/Ln aggregates reported to date using phosphonates as ligands. Magnetic susceptibility measurements reveal that compound 1 displays dominant ferromagnetic interactions between the adjacent metal ions with the best fit parameters for the exchanges are J(1) = 6.186 cm(-1), J(2) = 4.172 cm(-1), and with a result of S = 9 ground state confirmed by the M versus HT(-1) data, which indicates the spins of all the six Mn(IV) ions in the cluster are parallel to each other. In contrast, the data for 2 reveals

  15. Polysulfone functionalized with phosphonated poly(pentafluorostyrene) grafts for potential fuel cell applications.

    PubMed

    Dimitrov, Ivaylo; Takamuku, Shogo; Jankova, Katja; Jannasch, Patric; Hvilsted, Søren

    2012-08-28

    A multi-step synthetic strategy to polysulfone (PSU) grafted with phosphonated poly(pentafluorostyrene) (PFS) is developed. It involves controlled radical polymerization resulting in alkyne-end functional PFS. The next step is the modification of PSU with a number of azide side groups. The grafting of PFS onto PSU backbone is performed via the "click"-chemistry approach. In a final step, the PFS-grafts are subjected to the post phosphonation. The copolymers are evaluated as membranes for potential fuel cell applications through thermal analyses, water uptake, and conductivity measurements. The proposed synthetic route opens the possibility to tune copolymers' hydrophilic-hydrophobic balance to obtain membranes with an optimal balance between proton conductivity and mechanical properties. PMID:22623205

  16. Synthesis, antimicrobial, and alkylating properties of 3-phosphonic derivatives of chromone.

    PubMed

    Budzisz, E; Nawrot, E; Malecka, M

    2001-12-01

    Dimethyl 2,6-dimethyl-4-oxo-4H-chromen-3-yl-phosphonate (1a) and dimethyl 6-methyl-2-phenyl-4-oxo-4H-chromen-3-yl-phosphonate (1b) were synthesized and reacted with primary aliphatic amines to yield title compounds 4-6. Their antibacterial properties against Gram-positive and Gram-negative bacteria strains were tested by the MIC method. Four of seventeen tested compounds (1d, 3, 4a, and 4b) exhibit detectable activity against S. aureus. Some representative examples of newly synthesized compounds were tested for their alkylating properties in vitro in the Preussmann test. Compounds 1a, 1c, 1d, 3, 5d, and 6a possess highly alkylating activity toward standard derivative 4-(4'-nitrobenzyl)pyridine (NBP). PMID:11852533

  17. Synthetic molecular receptors for phosphates and phosphonates in sol-gel materials

    SciTech Connect

    Sasaki, D.Y.; Alam, T.M.; Assink, R.A.

    1997-12-01

    Synthetic receptors for phosphates and phosphonates have been generated in SiO{sub 2} xerogels via a surface molecular imprinting method. The monomer 3-trimethoxy silylpropyl-1-guanidinium chloride (1) was developed to prepare receptor sites capable of binding with substrates through a combination of ionic and hydrogen bond interactions. HPLC studies and adsorption isotherms performed in water have found that molecular imprinting affords a significant improvement in K{sub a} for phosphate and phosphonate affinity over a randomly functionalized xerogel. Affinities for these materials offer about an order of magnitude improvement in affinity compared to analogous small molecule receptors reported in the literature. The xerogel matrix appears to participate in host-guest interactions through anionic charge buildup with increasing pH.

  18. Synthesis and characterization of ruthenium and rhenium dyes with phosphonate anchoring groups.

    PubMed

    Braumüller, Markus; Schulz, Martin; Staniszewska, Magdalena; Sorsche, Dieter; Wunderlin, Markus; Popp, Jürgen; Guthmuller, Julien; Dietzek, Benjamin; Rau, Sven

    2016-05-31

    , a series of rhenium(i) tricarbonyl chloride complexes with bpy-R2 derivatives (bpy = 2,2'-bipyridine, R represents the substitution at the 4- and 4'-positions), and their corresponding trishomoleptic as well as heteroleptic ruthenium(ii) complexes and have been synthesized and characterized. Their applicability as immobilizable metal-organic chromophores in solar and photosynthesis cells is enabled by R, since it includes phosphonic ester groups as precursors for potent phosphonate anchoring groups. Conjugated linkers (phenylene and triazole moieties) serve as distance control between bpy and the anchor. Photophysical and electrochemical studies reveal pronounced effects of the aryl substitution. These effects were further investigated using resonance Raman experiments and supported by theoretical calculations. After hydrolysis the triazole containing was successfully immobilized on NiO, suggesting that its application in photovoltaic cells is feasible. The solid state structures of , , and are reported in this paper, enabling the determination of the distances and intermolecular interactions. PMID:27172842

  19. Preparation of sup 35 S-labeled polyphosphorothioate oligodeoxyribonucleotides by use of hydrogen phosphonate chemistry

    SciTech Connect

    Stein, A.; Iversen, P.L.; Subasinghe, C.; Cohen, J.S.; Stec, W.J.; Zon, G. )

    1990-07-01

    The title compounds were chemically synthesized as their 5'-dimethoxytrityl derivatives by base-catalyzed reaction of {sup 35}S-enriched elemental sulfur with support-bound hydrogen phosphonate oligomer. This was derived from adamantane carbonyl chloride-activated coupling of nucleotide hydrogen phosphonate monomers, and similarly activated capping with isopropyl phosphite. A convenient, disposable, reversed-phase cartridge was utilized to purify and isolate the 5'-dimethoxytrityl derivative for subsequent in situ detritylation and elution of the final product. The specific activity obtained for the title compounds was ca. 10(7) cpm/mumols-eq P(O)S-. The procedure should be readily adaptable to appropriate syntheses of other P-S containing analogs of DNA and RNA.

  20. Peptide length and prime-side sterics influence potency of peptide phosphonate protease inhibitors

    PubMed Central

    Brown, Christopher M.; Ray, Manisha; Eroy-Reveles, Aura A.; Egea, Pascal; Tajon, Cheryl; Craik, Charles S.

    2010-01-01

    Summary The ability to follow enzyme activity in a cellular context represents a challenging technological frontier that impacts fields ranging from disease pathogenesis to epigenetics. Activity-based probes (ABPs) label the active form of an enzyme via covalent modification of catalytic residues. Here we present an analysis of parameters influencing potency of peptide phosphonate ABPs for trypsin-fold S1A proteases, an abundant and important class of enzymes with similar substrate specificities. We find that peptide length and stability influence potency more than sequence composition and present structural evidence that steric interactions at the prime-side of the substrate-binding cleft affect potency in a protease-dependent manner. We introduce guidelines for the design of peptide phosphonate ABPs and demonstrate their utility in a live-cell labeling application that specifically targets active S1A proteases at the cell surface of cancer cells. PMID:21276938

  1. Versatile synthesis of oxime-containing acyclic nucleoside phosphonates--synthetic solutions and antiviral activity.

    PubMed

    Solyev, Pavel N; Jasko, Maxim V; Kleymenova, Alla A; Kukhanova, Marina K; Kochetkov, Sergey N

    2015-11-28

    New oxime-containing acyclic nucleoside phosphonates 9-{2-[(phosphonomethyl)oximino]ethyl}adenine (1), -guanine (2) and 9-{2-[(phosphonomethyl)oximino]propyl}adenine (3) with wide spectrum activity against different types of viruses were synthesized. The key intermediate, diethyl aminooxymethylphosphonate, was obtained by the Mitsunobu reaction. Modified conditions for the by-product separation (without chromatography and distillation) allowed us to obtain 85% yield of the aminooxy intermediate. The impact of DBU and Cs2CO3 on the N(9)/N(7) product ratio for adenine and guanine alkylation was studied. A convenient procedure for aminooxy group detection was found. The synthesized phosphonates were tested and they appeared to display moderate activity against different types of viruses (HIV, herpes viruses in cell cultures, and hepatitis C virus in the replicon system) without toxicity up to 1000 μM. PMID:26383895

  2. Synthesis, cytotoxic study and docking based multidrug resistance modulator potential analysis of 2-(9-oxoacridin-10(9H)-yl)-N-phenyl acetamides.

    PubMed

    Kumar, Rajesh; Kaur, Maninder; Bahia, Malkeet Singh; Silakari, Om

    2014-06-10

    The present study describes the synthesis of fifteen 2-(9-oxoacridin-10(9H)-yl)-N-phenyl acetamide derivatives (13a-o) through condensation of 2-chloro-N-phenyl acetamides (12a-o) with acridone molecule (10). All the synthesized compounds were screened for their anti-cancer activity against three diverse cell lines including breast (MCF-7), cervical (HeLa) and lung adenocarcinoma (A-549) employing standard MTT assay. Among synthesized molecules, 13k and 13l showed good cytotoxicity activity against considered three cancer cell lines. Additionally, in silico studies of multidrug resistance modulator (MDR) effects of these compounds was performed by docking simulation in the ATP binding site of P-gp. The results of docking simulation displayed important interactions of these molecules in the active site of this protein and predicted their MDR modulator behavior. PMID:24769346

  3. 2-Amino-N-[3-(2-chloro­benzo­yl)-5-ethyl­thio­phen-2-yl]acetamide

    PubMed Central

    Fun, Hoong-Kun; Chantrapromma, Suchada; Dayananda, A. S.; Yathirajan, H. S.; Ramesha, A. R.

    2012-01-01

    In the title compound, C15H15ClN2O2S, the 2-amino­acetamide N—C(=O)—C—N unit is approximately planar, with an r.m.s. deviation of 0.020 (4) Å. The central thio­phene ring makes dihedral angles of 7.84 (11) and 88.11 (11)°, respectively, with the 2-amino­acetamide unit and the 2-chloro­phenyl ring. An intra­molecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by an N—H⋯O hydrogen bond and weak C—H⋯O inter­actions into a chain along the c axis. A C—H⋯π inter­action is also present. PMID:22347140

  4. An unprecedented zero field neodymium(iii) single-ion magnet based on a phosphonic diamide.

    PubMed

    Gupta, Sandeep K; Rajeshkumar, Thayalan; Rajaraman, Gopalan; Murugavel, Ramaswamy

    2016-06-01

    The axial ligation by the -P[double bond, length as m-dash]O group of a phosphonic diamide in an air-stable Nd(iii) complex ensures a pseudo-D5h symmetry leading to the stabilization of the mJ = |±9/2〉 state; this in turn is responsible for the observed SIM behaviour at zero field and the slow relaxation of magnetization up to 8.0 K. PMID:27173026

  5. Chiral Vinylphosphonate and Phosphonate Analogues of the Immunosuppressive Agent FTY720

    PubMed Central

    Lu, Xuequan; Sun, Chaode; Valentine, William J.; E, Shuyu; Liu, Jianxiong; Tigyi, Gabor; Bittman, Robert

    2009-01-01

    The first enantioselective synthesis of chiral isosteric phosphonate analogues of FTY720 is described. One of these analogues, FTY720-(E)-vinylphosphonate (S)-5, but not its R enantiomer, elicited a potent anti-apoptotic effect in intestinal epithelial cells, suggesting that it exerts its action via the enantioselective activation of a receptor. (S)-5 failed to activate the sphingosine 1-phosphate type 1 (S1P1) receptor. PMID:19296586

  6. Thiol-ene and H-phosphonate-ene reactions for lipid modifications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The addition of H-E (E= -SR, -P(O)(OR)2 or -P(O)R2) to the carbon-carbon double bonds in lipids is a way to create new materials: lubricants, additives, polymers. In the current chapter, the radical addition of thiols (E= SR) and H-phosphonates (E= P(O)(OR)2) will be reviewed in detail. The kinetics...

  7. Novel carboranyl derivatives of nucleoside mono- and diphosphites and phosphonates: a synthetic investigation.

    PubMed

    Vyakaranam, Kamesh; Hosmane, Narayan S

    2004-01-01

    A number of nucleoside mono- and diphosphites and phosphonates containing 1,2-dicarbadodecaborane (12) (la-6b) at 5'-position of the sugar moiety have been synthesized in good yields. Experimental details along with the spectroscopic and analytical data, supporting the formation of the title compounds, are presented. These constitute a new generation of boron compounds that are envisioned to be useful in cancer treatment via Boron Neutron Capture Therapy (BNCT). PMID:18365067

  8. Variable temperature 1H and 13C NMR study of restricted rotation in N,N-bis(2-hydroxyethyl)acetamide

    NASA Astrophysics Data System (ADS)

    Aitken, R. Alan; Smith, Melanja H.; Wilson, Heather S.

    2016-06-01

    N,N-bis(2-hydroxyethyl)acetamide shows restricted rotation about the amide bond in both 1H and 13C NMR spectra rendering the two hydroxyethyl groups non-equivalent. A variable temperature study in CD3SOCD3 allowed estimation of the free energy barrier to rotation as 75.6 ± 0.2 kJ mol-1. Previously published data in CDCl3 appears to be erroneous.

  9. 2-(2,4-Dioxy-1,2,3,4-Tetrahydropyrimidin-1-yl)-N-(4-Phenoxyphenyl)-Acetamides as a Novel Class of Cytomegalovirus Replication Inhibitors

    PubMed Central

    Babkov, D. A.; Paramonova, M. P.; Ozerov, A. A.; Khandazhinskaya, A. L.; Snoeck, R.; Andrei, G.; Novikov, M. S.

    2015-01-01

    A series of novel uracil derivatives, bearing N-(4-phenoxyphenyl)acetamide moiety at N3 of a pyrimidine ring, has been synthesized. Their antiviral activity has been evaluated. It has been found that the novel compounds possess high inhibitory activity against replication of human cytomegalovirus (AD-169 and Davis strains) in HEL cell cultures. In addition, some of the derivatives proved to be inhibitory against varicella zoster virus. PMID:26798502

  10. Evaluation of 2'-hydroxyl protection in RNA-synthesis using the H-phosphonate approach.

    PubMed Central

    Rozners, E; Westman, E; Strömberg, R

    1994-01-01

    A number of different protecting groups were compared with respect to their usefulness for protection of 2'-hydroxyl functions during synthesis of oligoribonucleotides using the H-phosphonate approach. The comparison was between the t-butyldimethylsilyl (t-BDMSi), the o-chlorobenzoyl (o-CIBz), the tetrahydropyranyl (THP), the 1-(2-fluorophenyl)-4-methoxypiperidin-4-yl (Fpmp), the 1-(2-chloro-4-methylphenyl)-4-methoxypiperidin-4-yl (Ctmp), and the 1-(2-chloroethoxy)ethyl (Cee) protecting groups. All these groups were tested in synthesis of dodecamers, (Up)11U and (Up)11A, using 5'-O-(4-monomethoxytrityl) or (4,4'-dimethoxytrityl) uridine H-phosphonate building blocks carrying the respective 2'-protection. The performance of the t-BDMSi and o-CIBz derivatives were also compared in synthesis of (Up)19U. The most successful syntheses were clearly those where the t-butyldimethylsilyl group was used. The o-chlorobenzoyl group also gave satisfactory results but seems somewhat limited with respect to synthesis of longer oligomers. The results with all tested acetal derivatives (Fpmp, Ctmp, Cee, THP) were much less successful due to some accompanying cleavage of internucleotidic H-phosphonate functions during removal of 5'-O-protection (DMT). PMID:8127660

  11. Understanding the Mechanism of Action of Triazine-Phosphonate Derivatives as Flame Retardants for Cotton Fabric.

    PubMed

    Nguyen, Monique M; Al-Abdul-Wahid, M Sameer; Fontenot, Krystal R; Graves, Elena E; Chang, SeChin; Condon, Brian D; Grimm, Casey C; Lorigan, Gary A

    2015-01-01

    Countless hours of research and studies on triazine, phosphonate, and their combination have provided insightful information into their flame retardant properties on polymeric systems. However, a limited number of studies shed light on the mechanism of flame retardancy of their combination on cotton fabrics. The purpose of this research is to gain an understanding of the thermal degradation process of two triazine-phosphonate derivatives on cotton fabric. The investigation included the preparation of diethyl 4,6-dichloro-1,3,5-triazin-2-ylphosphonate (TPN1) and dimethyl (4,6-dichloro-1,3,5-triazin-2-yloxy) methyl phosphonate (TPN3), their application on fabric materials, and the studies of their thermal degradation mechanism. The studies examined chemical components in both solid and gas phases by using attenuated total reflection infrared (ATR-IR) spectroscopy, thermogravimetric analysis coupled with Fourier transform infrared (TGA-FTIR) spectroscopy, and 31P solid state nuclear magnetic resonance (31P solid state NMR), in addition to the computational studies of bond dissociation energy (BDE). Despite a few differences in their decomposition, TPN1 and TPN3 produce one common major product that is believed to help reduce the flammability of the fabric. PMID:26096432

  12. Evolution of an Amino Acid-based Prodrug Approach: Stay Tuned

    PubMed Central

    Krylov, Ivan S.; Kashemirov, Boris A.; Hilfinger, John M.; McKenna, Charles E.

    2013-01-01

    Certain acyclic nucleoside phosphonates (ANPs) such as (S)-HPMPC (cidofovir, Vistide®) and (S)-HPMPA have been shown to be active against a broad spectrum of DNA and retroviruses. However, their poor absorption as well as their toxicity limit the utilization of these therapeutics in the clinic. Nucleoside phosphonates are poorly absorbed primarily due to the presence of the phosphonic acid group, which ionizes at physiological pH. When dosed intravenously they display dose-limiting nephrotoxicity due to their accumulation in the kidney. To overcome these limitations, nucleoside phosphonate prodrug strategies have taken center stage in the development pathway and a number of different approaches are at various stages of development. Our efforts have focused on the development of ANP prodrugs in which a benign amino acid promoiety masks a phosphonate P-OH via a hydroxyl side chain. The design of these prodrugs incorporates multiple chemical groups (the P−X−C linkage, the amino acid stereochemistry, the C-terminal and N-terminal functional groups) that can be been tuned to modify absorption, pharmacokinetic and efficacy properties with the goal of improving overall prodrug performance. PMID:23339402

  13. The use of functionalized monoalkyl phosphates and phosphonates in the colloidal processing of oxide ceramic powders

    NASA Astrophysics Data System (ADS)

    Radsick, Timothy Carl

    The purpose of this study was to develop phosphorous-based chemicals that could be used to modify the interparticle pair potential of several oxide ceramic particles, thereby enabling their use in colloidal processing schemes. Several procedures for the synthesis of 11-12 carbon alpha,o-functionalized monoalkyl phosphates and phosphonates were developed. Because of its simplicity and its use of mild reagents, a procedure based on the Michaelis-Arbuzov rearrangement was selected to produce the bulk of the chemicals used in this study. Carboxyl- and hydroxyl-terminated monoalkyl phosphonates were adsorbed onto alumina and zirconia powders using either aqueous-based or solvent-based methods to produce a monolayer of "brushlike" steric molecules. In the aqueous-based methods, powders were processed at pH values below their isoelectric point in order to produce a positive charge on the powder, thereby attracting the negatively charged phosphate or phosphonate group onto the powder surface to form the steric monolayer. In solvent-based methods, powder was suspended in an acetone solution of the phosphonates, heated at reflux, washed, dried and heat treated at 120°C under vacuum. The zeta potential of the coated powders was measured to quantify the degree of steric layer adsorption and the shift in the isoelectric point. Slurries of coated alumina and zirconia were prepared having 20 vol % powder. Rheological behavior was studied by measuring viscosity as a function of shear rate for slurries of various pH values and counterion concentrations. Slurries with powder processed via the solvent method were the least sensitive to changes in slurry pH and were straightforward to prepare. It is thought that the solvent-based coating procedure produced a stronger, multi-dentate powder-phosphonate bond than that of the aqueous-based procedure. Dispersed and coagulated slurries were able to be prepared over a wide pH range, including at the isoelectric point of the uncoated powders

  14. Which metabolic imaging, besides bone scan with 99mTc-phosphonates, for detecting and evaluating bone metastases in prostatic cancer patients? An open discussion.

    PubMed

    Bombardieri, E; Setti, L; Kirienko, M; Antunovic, L; Guglielmo, P; Ciocia, G

    2015-12-01

    Prostate cancer bone metastases occur frequently in advanced cancer and this is matter of particular attention, due to the great impact on patient's management and considering that a lot of new emerging therapeutic options have been recently introduced. Imaging bone metastases is essential to localize lesions, to establish their size and number, to study characteristics and changes during therapy. Besides radiological imaging, nuclear medicine modalities can image their features and offer additional information about their metabolic behaviour. They can be classified according to physical characteristics, type of detection, mechanism of uptake, availability for daily use. The physiopathology of metastases formation and the mechanisms of tracer uptake are essential to understand the interpretation of nuclear medicine images. Therefore, radiopharmaceuticals for bone metastases can be classified in agents targeting bone (99mTc-phosphonates, 18F-fluoride) and those targeting prostatic cancer cells (18F-fluoromethylcholine, 11C-choline, 18F-fluorodeoxyglucose). The modalities using the first group of tracers are planar bone scan, SPECT or SPECT/CT with 99mTc-diphosphonates, and 18F-fluoride PET/CT, while the modalities using the second group include 18F/11C-choline derivatives PET/CT, 18F-FDG PET/CT and PET/CT scans with several other radiopharmaceuticals described in the literature, such as 18F/11C-acetate derivatives, 18F-fluoro-5α-dihydrotestosterone (FDHT), 18F-anti-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC), 18F-2'-fluoro-5-methyl-1-β-D-arabinofuranosyluracil (FMAU) and 68Ga-labeled-prostate specific membrane antigen (PMSA) PET/TC. However, since data on clinical validation for these last novel modalities are not conclusive and/or are not still sufficient in number, at present they can be still considered as promising tools under evaluation. The present paper considers the nuclear modalities today available for the clinical routine. This overview wants

  15. Discovery of 2-(6-(5-Chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide (PF-06282999): A Highly Selective Mechanism-Based Myeloperoxidase Inhibitor for the Treatment of Cardiovascular Diseases.

    PubMed

    Ruggeri, Roger B; Buckbinder, Leonard; Bagley, Scott W; Carpino, Philip A; Conn, Edward L; Dowling, Matthew S; Fernando, Dilinie P; Jiao, Wenhua; Kung, Daniel W; Orr, Suvi T M; Qi, Yingmei; Rocke, Benjamin N; Smith, Aaron; Warmus, Joseph S; Zhang, Yan; Bowles, Daniel; Widlicka, Daniel W; Eng, Heather; Ryder, Tim; Sharma, Raman; Wolford, Angela; Okerberg, Carlin; Walters, Karen; Maurer, Tristan S; Zhang, Yanwei; Bonin, Paul D; Spath, Samantha N; Xing, Gang; Hepworth, David; Ahn, Kay; Kalgutkar, Amit S

    2015-11-12

    Myeloperoxidase (MPO) is a heme peroxidase that catalyzes the production of hypochlorous acid. Clinical evidence suggests a causal role for MPO in various autoimmune and inflammatory disorders including vasculitis and cardiovascular and Parkinson's diseases, implying that MPO inhibitors may represent a therapeutic treatment option. Herein, we present the design, synthesis, and preclinical evaluation of N1-substituted-6-arylthiouracils as potent and selective inhibitors of MPO. Inhibition proceeded in a time-dependent manner by a covalent, irreversible mechanism, which was dependent upon MPO catalysis, consistent with mechanism-based inactivation. N1-Substituted-6-arylthiouracils exhibited low partition ratios and high selectivity for MPO over thyroid peroxidase and cytochrome P450 isoforms. N1-Substituted-6-arylthiouracils also demonstrated inhibition of MPO activity in lipopolysaccharide-stimulated human whole blood. Robust inhibition of plasma MPO activity was demonstrated with the lead compound 2-(6-(5-chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide (PF-06282999, 8) upon oral administration to lipopolysaccharide-treated cynomolgus monkeys. On the basis of its pharmacological and pharmacokinetic profile, PF-06282999 has been advanced to first-in-human pharmacokinetic and safety studies. PMID:26509551

  16. A (Fluoroalkyl)Guanidine Modulates the Relaxivity of a Phosphonate-Containing T1-Shortening Contrast Agent

    PubMed Central

    Wu, Xinping; Dawsey, Anna C.; Siriwardena-Mahanama, Buddhima N.; Allen, Matthew J.; Williams, Travis J.

    2014-01-01

    Responsive magnetic resonance imaging (MRI) contrast agents, those that change their relaxivity according to environmental stimuli, have promise as next generation imaging probes in medicine. While several of these are known based on covalent modification of the contrast agents, fewer are known based on controlling non-covalent interactions. We demonstrate here accentuated relaxivity of a T1-shortening contrast agent, Gd-DOTP5− based on non-covalent, hydrogen bonding of Gd-DOTP5− with a novel fluorous amphiphile. By contrast to the phosphonate-containing Gd-DOTP5− system, the relaxivity of the analogous clinically approved contrast agent, Gd-DOTA− is unaffected by the same fluorous amphiphile under similar conditions. Mechanistic studies show that placing the fluorous amphiphile in proximity of the gadolinium center in Gd-DOTP5− caused an increase in τm (bound-water residence lifetime or the inverse of water exchange rate, τm = 1/kex) and an increase in τR (rotational correlation time), with τR being the factor driving enhanced relaxivity. Further, these effects were not observed when Gd-DOTA− was treated with the same fluorous amphiphile. Thus, Gd-DOTP5− and Gd-DOTA− respond to the fluorous amphiphile differently, presumably because the former binds to the amphiphile with higher affinity. (DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraphosphonic acid; DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). PMID:25431503

  17. Recognition of N-alkyl and N-aryl acetamides by N-alkyl ammonium resorcinarene chlorides.

    PubMed

    Beyeh, N Kodiah; Ala-Korpi, Altti; Cetina, Mario; Valkonen, Arto; Rissanen, Kari

    2014-11-10

    N-alkyl ammonium resorcinarene chlorides are stabilized by an intricate array of intra- and intermolecular hydrogen bonds that leads to cavitand-like structures. Depending on the upper-rim substituents, self-inclusion was observed in solution and in the solid state. The self-inclusion can be disrupted at higher temperatures, whereas in the presence of small guests the self-included dimers spontaneously reorganize to 1:1 host-guest complexes. These host compounds show an interesting ability to bind a series of N-alkyl acetamide guests through intermolecular hydrogen bonds involving the carbonyl oxygen (C=O) atoms and the amide (NH) groups of the guests, the chloride anions (Cl(-)) and ammonium (NH2(+)) cations of the hosts, and also through CH⋅⋅⋅π interactions between the hosts and guests. The self-included and host-guest complexes were studied by single-crystal X-ray diffraction, NMR titration, and mass spectrometry. PMID:25257765

  18. Elucidation of Structural Elements for Selectivity across Monoamine Transporters: Novel 2-[(Diphenylmethyl)sulfinyl]acetamide (Modafinil) Analogues

    PubMed Central

    2015-01-01

    2-[(Diphenylmethyl)sulfinyl]acetamide (modafinil, (±)-1) is a unique dopamine uptake inhibitor that binds the dopamine transporter (DAT) differently than cocaine and may have potential for the treatment of psychostimulant abuse. To further investigate structural requirements for this divergent binding mode, novel thio- and sulfinylacetamide and ethanamine analogues of (±)-1 were synthesized wherein (1) the diphenyl rings were substituted with methyl, trifluoromethyl, and halogen substituents and (2) substituents were added to the terminal amide/amine nitrogen. Halogen substitution of the diphenyl rings of (±)-1 gave several amide analogues with improved binding affinity for DAT and robust selectivity over the serotonin transporter (SERT), whereas affinity improved at SERT over DAT for the p-halo-substituted amine analogues. Molecular docking studies, using a subset of analogues with DAT and SERT homology models, and functional data obtained with DAT (A480T) and SERT (T497A) mutants defined a role for TM10 in the substrate/inhibitor S1 binding sites of DAT and SERT. PMID:24494745

  19. Natural bond orbital analysis, electronic structure and vibrational spectral analysis of N-(4-hydroxyl phenyl) acetamide: A density functional theory

    NASA Astrophysics Data System (ADS)

    Govindasamy, P.; Gunasekaran, S.; Ramkumaar, G. R.

    2014-09-01

    The Fourier transform infrared (FT-IR) and FT-Raman spectra of N-(4-hydroxy phenyl) acetamide (N4HPA) of painkiller agent were recorded in the region 4000-450 cm-1 and 4000-50 cm-1 respectively. Density functional theory (DFT) has been used to calculate the optimized geometrical parameter, atomic charges, and vibrational wavenumbers and intensity of the vibrational bands. The computed vibrational wave numbers were compared with the FT-IR and FT-Raman experimental data. The computational calculations at DFT/B3LYP level with 6-31G(d,p), 6-31++G(d,p), 6-311G(d,p) and 6-311++G(d,p) basis sets. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes calculated using Vibrational energy distribution analysis (VEDA 4) program. The oscillator’s strength calculated by TD-DFT and N4HPA is approach complement with the experimental findings. The NMR chemical shifts 13C and 1H were recorded and calculated using the gauge independent atomic orbital (GIAO) method. The molecular electrostatic potential (MESP) and electron density surfaces of the molecule were constructed. The Natural charges and intermolecular contacts have been interpreted using Natural Bond orbital (NBO) analysis the HOMO-LUMO energy gap has been calculated. The thermodynamic properties like entropy, heat capacity and zero vibrational energy have been calculated.

  20. Synthesis of nitro(benzo)thiazole acetamides and in vitro antiprotozoal effect against amitochondriate parasites Giardia intestinalis and Trichomonas vaginalis.

    PubMed

    Navarrete-Vázquez, Gabriel; Chávez-Silva, Fabiola; Colín-Lozano, Blanca; Estrada-Soto, Samuel; Hidalgo-Figueroa, Sergio; Guerrero-Álvarez, Jorge; Méndez, Sara T; Reyes-Vivas, Horacio; Oria-Hernández, Jesús; Canul-Canché, Jaqueline; Ortiz-Andrade, Rolffy; Moo-Puc, Rosa

    2015-05-01

    We synthesized four 5-nitrothiazole (1-4) and four 6-nitrobenzothiazole acetamides (5-8) using an easy two step synthetic route. All compounds were tested in vitro against amitochondriate parasites Giardia intestinalis and Trichomonas vaginalis, showing excellent antiprotozoal effects. IC₅₀'s of the most potent compounds range from nanomolar to low micromolar order, being more active than their drugs of choice. Compound 1 (IC₅₀=122 nM), was 44-times more active than Metronidazole, and 10-fold more effective than Nitazoxanide against G. intestinalis and showed good trichomonicidal activity (IC₅₀=2.24 μM). This compound did not display in vitro cytotoxicity against VERO cells. The in vitro inhibitory effect of compounds 1-8 and Nitazoxanide against G. intestinalis fructose-1,6-biphosphate aldolase (GiFBPA) was evaluated as potential drug target, showing a clear inhibitory effect over the enzyme activity. Molecular docking of compounds 1, 4 and Nitazoxanide into the ligand binding pocket of GiFBPA, revealed contacts with the active site residues of the enzyme. Ligand efficiency metrics of 1 revealed optimal combinations of physicochemical and antiprotozoal properties, better than Nitazoxanide. PMID:25801157

  1. Anticonvulsant efficacy/safety properties of 2-amino-N-(1,2-diphenylethyl)acetamide hydrochloride.

    PubMed

    Palmer, G C; Stagnitto, M L; Garske, G E; Napier, J J; Harris, E W; Kaiser, F C; Griffith, R C; Woodhead, J H; White, H S; Wolf, H H

    1995-06-01

    2-Amino-N-(1,2-diphenylethyl)-acetamide-hydrochloride (FPL 13950) was profiled preclinically in rodents for efficacy against convulsions, as well as for acute safety/behavioral observations. FPL 13950 exhibited good oral efficacy and duration of action with respect to prevention of seizures elicited by maximal electroshock-shock in both rats and mice. Tolerance to protection against maximal electroshock and hexobarbital-induced sleep-time was not evident after subchronic drug administration. FPL 13950 also prevented convulsions/mortality in mice after i.v. dosing with N-methyl-D, L-aspartate, however, it was ineffective against other types of chemically induced convulsions, as well as bicorneal kindling. High oral doses produced neural impairment in both mice and rats and hyperactivity in rats. Sequential administration of yet higher doses elicited tonic/clonic convulsions culminating in death. During i.v. infusion of metrazol in mice, high i.p. doses of FPL 13950 shortened the latency to first twitch and clonus. No increase in the startle response or phencyclidine-like behavior was evident after oral dosing in rats. PMID:7791072

  2. Hydrothermal preparation and characterization of ultralong strontium-substituted hydroxyapatite whiskers using acetamide as homogeneous precipitation reagent.

    PubMed

    Xu, Jianqiang; Yang, Yaoqi; Wan, Rong; Shen, Yuhui; Zhang, Weibin

    2014-01-01

    The ultralong strontium- (Sr-) substituted hydroxyapatite (SrHAp) whiskers were successfully prepared using acetamide as homogeneous precipitation reagent. The effect of the Sr substitution amount on the lattice constants and proliferation of human osteoblast cells (MG-63) was further investigated. The results showed that the SrHAp whiskers with diameter of 0.2-12 μm and ultralong length up to 200 μm were obtained and the Sr substitution level could be facilely tailored by regulating the initial molar ratio of Sr/(Sr + Ca) in raw materials. The Sr(2+) replaced part of Ca(2+) and the lattice constants increased apparently with the increase of the Sr substitution amount. Compared with the pure HAp whiskers, the Sr substitution apparently stimulated the proliferation of MG-63 at certain extracted concentrations. Our study suggested that the obtained SrHAp whiskers might be used as bioactive and mechanical reinforcement materials for hard tissue regeneration applications. PMID:24592192

  3. Hydrothermal Preparation and Characterization of Ultralong Strontium-Substituted Hydroxyapatite Whiskers Using Acetamide as Homogeneous Precipitation Reagent

    PubMed Central

    Xu, Jianqiang; Yang, Yaoqi; Wan, Rong; Zhang, Weibin

    2014-01-01

    The ultralong strontium- (Sr-) substituted hydroxyapatite (SrHAp) whiskers were successfully prepared using acetamide as homogeneous precipitation reagent. The effect of the Sr substitution amount on the lattice constants and proliferation of human osteoblast cells (MG-63) was further investigated. The results showed that the SrHAp whiskers with diameter of 0.2–12 μm and ultralong length up to 200 μm were obtained and the Sr substitution level could be facilely tailored by regulating the initial molar ratio of Sr/(Sr + Ca) in raw materials. The Sr2+ replaced part of Ca2+ and the lattice constants increased apparently with the increase of the Sr substitution amount. Compared with the pure HAp whiskers, the Sr substitution apparently stimulated the proliferation of MG-63 at certain extracted concentrations. Our study suggested that the obtained SrHAp whiskers might be used as bioactive and mechanical reinforcement materials for hard tissue regeneration applications. PMID:24592192

  4. Hydrothermal synthesis, crystal structure and properties of a novel chain coordination polymer constructed by tetrafunctional phosphonate anions and cobalt ions

    SciTech Connect

    Guan, Lei; Wang, Ying

    2015-08-15

    A novel cobalt phosphonate, [Co(HL)(H{sub 2}O){sub 3}]{sub n} (1) (L=N(CH{sub 2}PO{sub 3}H){sub 3}{sup 3−}) has been synthesized by hydrothermal reaction at 150 °C and structurally characterized by X-ray diffraction, infrared spectroscopy, elemental and thermogravimetric analysis. Complex 1 features a 1D chain structure with double-channel built from CoO{sub 6} octahedra bridged together by the phosphonate groups. Each cobalt ion is octahedrally coordinated by three phosphonate oxygen atoms and three water molecules. The coordinated water molecules can form the hydrogen bonds with the phosphonate oxygen atoms to link the 1D chains, building a 2D layered structure, further resulting in a 3D network. The luminescence spectrum indicates an emission maximum at 435 nm. The magnetic susceptibility curve exhibits a dominant antiferromagnetic behavior with a weakly ferromagnetic component at low temperatures. - Graphical abstract: The connectivity between cobalt ions and the ligands results in a chain structure with a 1D double-channel structure, which is constructed by A-type subrings and B-type subrings. - Highlights: • The tetrafunctional phosphonate ligand was used as the ligand. • A novel chain structure can be formed by A-type rings and B-type rings. • Two types of rings can form a 1D double-channel structure, along the c-axis.

  5. A new class of acyclic nucleoside phosphonates: synthesis and biological activity of 9-[[(phosphonomethyl)aziridin-1-yl]methyl]guanine (PMAMG) and analogues.

    PubMed

    Abu Sheikha, Ghassan; La Colla, Paolo; Loi, Anna Giulia

    2002-10-01

    A new class of acyclic nucleoside phosphonates PMAMG, PMAMA, PMAMC, and PMAMT (compounds 1, 2, 3 and 4) have been synthesized and tested in vitro against a wide variety of viruses, fungi and bacteria. PMAMG (1) was synthesized by the alkylation reaction of acetylguanine with the phosphonate side-chain, diisopropyl [[2-(bromomethyl)aziridin-1-yl

  6. Synthesis and comparison of the biological activity of monocyclic phosphonate, difluorophosphonate and phosphate analogs of the natural AChE inhibitor cyclophostin.

    PubMed

    Martin, Benjamin P; Vasilieva, Elena; Dupureur, Cynthia M; Spilling, Christopher D

    2015-12-15

    New monocyclic phosphate, phosphonate and difluorophosphonate analogs of the natural AChE inhibitor cyclophostin were synthesized and their activity toward human AChE examined. Surprisingly, the phosphate, phosphonate, and difluorophosphonate analogs all showed diminished activity when compared with the natural product. PMID:26585276

  7. Selective synthesis of substituted pyrrole-2-phosphine oxides and -phosphonates from 2H-azirines and enolates from acetyl acetates and malonates.

    PubMed

    Palacios, Francisco; Ochoa de Retana, Ana M; Vélez del Burgo, Ander

    2011-11-18

    A simple and efficient selective synthesis of 1H-pyrrole-2-phosphine oxides 3 and -phosphonates 7 by addition of enolates derived from acetyl acetates to 2H-azirinylphosphine oxide 1 and -phosphonate 6 is reported. Nucleophilic addition of enolates derived from diethyl malonate to 2H-azirines 1 and 6 led to the formation of functionalized 2-hydroxy-1H-pyrrole-5-phosphine oxide 9 and -phosphonate 10, while vinylogous α-aminoalkylphosphine oxides 14 and -phosphonate 15 may be obtained from azirines and the enolate derived from diethyl 2-phenylmalonate. Ring closure of vinylogous derivatives 14 and 15 in the presence of base led to the formation of 1,5-dihydro-3-pyrrolin-2-ones containing a phosphine oxide 17 or a phosphonate group 18. PMID:21999212

  8. Copper Lanthanide Phosphonate Cages: Highly Symmetric {Cu3Ln9P6} and {Cu6Ln6P6} Clusters with C3v and D3h Symmetry.

    PubMed

    Moreno Pineda, Eufemio; Heesing, Christian; Tuna, Floriana; Zheng, Yan-Zhen; McInnes, Eric J L; Schnack, Jürgen; Winpenny, Richard E P

    2015-07-01

    Two families of copper lanthanide phosphonate clusters have been obtained through reaction of [Cu2(O2C(t)Bu)4(HO2C(t)Bu)2] and either Ln(NO3)3·nH2O or [Ln2(O2C(t)Bu)6(HO2C(t)Bu)6] and tert-butylphosphonic acid or an amino-functionalized phosphonic acid. The clusters, with general formula [Cu(MeCN)4][Cu3Ln9(μ3-OH)7(O3P(t)Bu)6(O2C(t)Bu)15] and [Cu6Ln6(μ3-OH)6(O3PC(NH2)Me2)6(O2C(t)Bu)12], were structurally characterized through single crystal X-ray diffraction and possess highly symmetric metal cores with approximately C3v and D3h point symmetry, respectively. We have investigated the possible application of the isotropic analogues in magnetic cooling, where we were able to observe that up to around 70% of the theoretical magnetic entropy change is obtained. Simulation of the magnetic data shows antiferromagnetic coupling between the spin centers, which explains the magnetic entropy value observed. PMID:26061255

  9. Hydrothermal synthesis for new multifunctional materials: A few examples of phosphates and phosphonate-based hybrid materials

    NASA Astrophysics Data System (ADS)

    Rueff, Jean-Michel; Poienar, Maria; Guesdon, Anne; Martin, Christine; Maignan, Antoine; Jaffrès, Paul-Alain

    2016-04-01

    Novel physical or chemical properties are expected in a great variety of materials, in connection with the dimensionality of their structures and/or with their nanostructures, hierarchical superstructures etc. In the search of new advanced materials, the hydrothermal technique plays a crucial role, mimicking the nature able to produce fractal, hyperbranched, urchin-like or snow flake structures. In this short review including new results, this will be illustrated by examples selected in two types of materials, phosphates and phosphonates, prepared by this method. The importance of the synthesis parameters will be highlighted for a magnetic iron based phosphates and for hybrids containing phosphonates organic building units crystallizing in different structural types.

  10. A Sustainable and Efficient Synthesis of Benzyl Phosphonates Using PEG/KI Catalytic System

    PubMed Central

    Disale, Shamrao; Kale, Sandip; Abraham, George; Kahandal, Sandeep; Sawarkar, Ashish N.; Gawande, Manoj B.

    2016-01-01

    An efficient and expedient protocol for the synthesis of benzyl phosphonates using KI/K2CO3 as a catalytic system and PEG-400 as benign solvent has been developed. The reaction proceeds smoothly at room temperature achieving excellent selectivity and yield of the corresponding products. The combination of PEG-400, KI, and K2CO3 in this reaction avoids the need of volatile/toxic organic solvents and reactive alkali metals or metal nanoparticles/hydrides. We believe that this benign combination (PEG-400 and KI) could be used for other related organic transformations. PMID:27579301

  11. Phosphonate derivatives of tetraazamacrocycles as new inhibitors of protein tyrosine phosphatases.

    PubMed

    Kobzar, Oleksandr L; Shevchuk, Michael V; Lyashenko, Alesya N; Tanchuk, Vsevolod Yu; Romanenko, Vadim D; Kobelev, Sergei M; Averin, Alexei D; Beletskaya, Irina P; Vovk, Andriy I; Kukhar, Valery P

    2015-07-21

    α,α-Difluoro-β-ketophosphonated derivatives of tetraazamacrocycles were synthesized and found to be potential inhibitors of protein tyrosine phosphatases. N-Substituted conjugates of cyclam and cyclen with bioisosteric phosphonate groups displayed good activities toward T-cell protein tyrosine phosphatase with IC50 values in the micromolar to nanomolar range and showed selectivity over PTP1B, CD45, SHP2, and PTPβ. Kinetic studies indicated that the inhibitors can occupy the region of the active site of TC-PTP. This study demonstrates a new approach which employs tetraazamacrocycles as a molecular platform for designing inhibitors of protein tyrosine phosphatases. PMID:26058329

  12. A Sustainable and Efficient Synthesis of Benzyl Phosphonates Using PEG/KI Catalytic System.

    PubMed

    Disale, Shamrao; Kale, Sandip; Abraham, George; Kahandal, Sandeep; Sawarkar, Ashish N; Gawande, Manoj B

    2016-01-01

    An efficient and expedient protocol for the synthesis of benzyl phosphonates using KI/K2CO3 as a catalytic system and PEG-400 as benign solvent has been developed. The reaction proceeds smoothly at room temperature achieving excellent selectivity and yield of the corresponding products. The combination of PEG-400, KI, and K2CO3 in this reaction avoids the need of volatile/toxic organic solvents and reactive alkali metals or metal nanoparticles/hydrides. We believe that this benign combination (PEG-400 and KI) could be used for other related organic transformations. PMID:27579301

  13. Comparison of chiral separations of aminophosphonic acids and their aminocarboxylic acid analogs using a crown ether column.

    PubMed

    Barnhart, Wesley W; Xia, Xiaoyang; Jensen, Randy; Gahm, Kyung H

    2013-07-01

    Crown ethers are capable of complexing with primary amines and have been utilized in chromatography to separate amino acid racemates. This application has been extended to resolve (1-amino-1-phenylmethyl)phosphonic acid and (1-aminoethyl)phosphonic acid racemates, along with their aminocarboxylic acid analogs (2-phenylglycine and alanine, respectively), via a ChiroSil RCA crown ether based chiral stationary phase. Effects of the organic modifier, temperature, and acid type and concentration on retention and selectivity were also investigated. Trends in retention and selectivity varied between aminophosponic acids and their aminocarboxylic analogs. Computer modeling and (1)H NMR analyses were performed to potentially gain a better understanding of interactions of the aforementioned molecules with the ChiroSil RCA chiral stationary phase. Theoretical predictions of the most stable conformations for (R)- and (S)-enantiomers were compared to elution order; it was found that the elution order agreed with molecular modeling such that the longest retention correlated with the predicted most stable complex between the enantiomer and crown ether. (1)H NMR demonstrated interactions of aminophosphonic and aminocarboxylic racemates with (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid in solution and was utilized to determine enantiomeric excess of (1-amino-1-phenylmethyl)phosphonic acid after its enantioenrichment via crystallization through diastereomeric salt formation with the crown ether followed by filtration. PMID:23703726

  14. Synthesis, Cu(II) complexation, 64Cu-labeling and biological evaluation of cross-bridged cyclam chelators with phosphonate pendant arms†

    PubMed Central

    Ferdani, Riccardo; Stigers, Dannon J.; Fiamengo, Ashley L.; Wei, Lihui; Li, Barbara T. Y.; Golen, James A.; Rheingold, Arnold L.; Weisman, Gary R.; Wong, Edward H.; Anderson, Carolyn J.

    2012-01-01

    A new class of cross-bridged cyclam-based macrocycles featuring phosphonate pendant groups has been developed. 1,4,8,11-tetraazacyclotetradecane-1,8-di(methanephosphonic acid) (CB-TE2P, 1) and 1,4,8,11-tetraazacyclotetradecane-1-(methanephosphonic acid)-8-(methanecarboxylic acid) (CB-TE1A1P, 2) have been synthesized and have been shown to readily form neutral copper (II) complexes at room temperature as the corresponding dianions. Both complexes showed high kinetic inertness to demetallation and crystal structures confirmed complete encapsulation of copper (II) ion within each macrocycle’s cleft-like structure. Unprecedented for cross-bridged cyclam derivatives, both CB-TE2P (1) and CB-TE1A1P (2) can be radiolabeled with 64Cu at room temperature in less than 1 hour with specific activities >1mCi/μg. The in vivo behavior of both 64Cu-CB-TE2P and 64Cu-CB-TE1A1P were investigated through biodistribution studies using healthy, male, Lewis rats. Both new compounds showed rapid clearance with similar or lower accumulation in non-target organs/tissues when compared to other copper chelators including CB-TE2A, NOTA and Diamsar. PMID:22170043

  15. Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): time-resolved fluorescence measurements and all-atom molecular dynamics simulations.

    PubMed

    Das, Anuradha; Das, Suman; Biswas, Ranjit

    2015-01-21

    Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ∼120-145 K above the measured glass transition temperatures (∼207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (∼70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α2) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems. PMID:25612718

  16. Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Das, Anuradha; Das, Suman; Biswas, Ranjit

    2015-01-01

    Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ˜120-145 K above the measured glass transition temperatures (˜207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (˜70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α2) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.

  17. Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations

    SciTech Connect

    Das, Anuradha; Das, Suman; Biswas, Ranjit

    2015-01-21

    Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH{sub 3}CONH{sub 2}) and urea (NH{sub 2}CONH{sub 2}) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH{sub 3}CONH{sub 2} + (1 − f)NH{sub 2}CONH{sub 2}] have been studied in a temperature range of 328-353 K which is ∼120-145 K above the measured glass transition temperatures (∼207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (∼70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α{sub 2}) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.

  18. Acid monolayer functionalized iron oxide nanoparticle catalysts

    NASA Astrophysics Data System (ADS)

    Ikenberry, Myles

    Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80° and starch at 130°, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide

  19. Analytical methods to determine phosphonic and amino acid group-containing pesticides.

    PubMed

    Stalikas, C D; Konidari, C N

    2001-01-12

    A comprehensive view on the possibilities of the most recently developed chromatographic methods and emerging techniques in the analysis of pesticides glyphosate, glufosinate, bialaphos and their metabolites is presented. The state-of-the-art of the individual pre-treatment steps (extraction, pre-concentration, clean-up, separation, quantification) of the employed analytical methods for this group of chemicals is reviewed. The advantages and drawbacks of the described analytical methods are discussed and the present status and future trends are outlined. PMID:11217016

  20. Discovery of phosphonic acid natural products by mining the genomes of 10,000 actinomycetes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although natural products have been a particularly rich source of human medicines, the rate at which new molecules are being discovered is declining precipitously. Based on the large number of natural product biosynthetic genes in microbial genomes, many have suggested “genome mining” as an approach...

  1. Proton conductive inorganic-organic hybrid membranes functionalized with phosphonic acid for polymer electrolyte fuel cell

    NASA Astrophysics Data System (ADS)

    Umeda, Junji; Suzuki, Masashi; Kato, Masaki; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu

    Proton conductive sol-gel derived hybrid membranes were synthesized from aromatic derivatives of methoxysilanes and ethyl 2-[3-(dihydroxyphosphoryl)-2-oxapropyl]acrylate (EPA). Two aromatic derivatives of methoxysilanes with different number of methoxy groups were used as the starting materials. Hybrid membranes from difunctional (methyldimethoxysilylmethyl)styrene (MDMSMS(D))/EPA revealed a higher chemical stability and mechanical properties than those from monofunctional (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA. The membrane-electrode assembly (MEA) using the hybrid membranes as electrolytes worked as a fuel cell at 100 °C under saturated humidity. The DMMSMS(M)/EPA membrane-based MEA showed a larger current density than that from MDMSMS(D)/EPA. On the other hand, the MDMSMS(D)/EPA membrane-based MEA exhibited higher open circuit voltages than the DMMSMS(M)/EPA-based MEA, and was stable during fuel cell operation at 80 °C at least for 48 h.

  2. 40 CFR 704.95 - Phosphonic acid, [1,2-ethanediyl-bis[nitrilobis-(methylene)

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... hydrogen, (OC-6-21)- 67969-67-9 Cobaltate (6-), ] tetrakis- ] (8-)-N,N′,O,O″,O″″,O″″″]-, pentasodium hydrogen, (OC-6-21)- 67989-89-3 Cuprate (6-), ] tetrakis- ] (8-)]-, pentapotassium hydrogen, (OC-6-21)- 68025-39-8 Cobaltate (6-), ] tetrakis- ] (6-)-N,N′,O,O″,O″″,O″″″]-, pentaammonium hydrogen,...

  3. 40 CFR 704.95 - Phosphonic acid, [1,2-ethanediyl-bis[nitrilobis-(methylene)

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... hydrogen, (OC-6-21)- 67969-67-9 Cobaltate (6-), ] tetrakis- ] (8-)-N,N′,O,O″,O″″,O″″″]-, pentasodium hydrogen, (OC-6-21)- 67989-89-3 Cuprate (6-), ] tetrakis- ] (8-)]-, pentapotassium hydrogen, (OC-6-21)- 68025-39-8 Cobaltate (6-), ] tetrakis- ] (6-)-N,N′,O,O″,O″″,O″″″]-, pentaammonium hydrogen,...

  4. 40 CFR 704.95 - Phosphonic acid, [1,2-ethanediyl-bis[nitrilobis-(methylene)

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... hydrogen, (OC-6-21)- 67969-67-9 Cobaltate (6-), ] tetrakis- ] (8-)-N,N′,O,O″,O″″,O″″″]-, pentasodium hydrogen, (OC-6-21)- 67989-89-3 Cuprate (6-), ] tetrakis- ] (8-)]-, pentapotassium hydrogen, (OC-6-21)- 68025-39-8 Cobaltate (6-), ] tetrakis- ] (6-)-N,N′,O,O″,O″″,O″″″]-, pentaammonium hydrogen,...

  5. 40 CFR 704.95 - Phosphonic acid, [1,2-ethanediyl-bis[nitrilobis-(methylene)

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ascertainable by them. (1) Initial Report: (i) Name and Chemical Abstracts Service Registry Number of the...) Follow-up Report: (i) Name and Chemical Abstracts Service Registry Number of the substance for which the... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT REPORTING AND RECORDKEEPING REQUIREMENTS Chemical-Specific...

  6. Synthesis of polymeric phosphonates for selective delivery of radionuclides to osteosarcoma.

    PubMed

    Popwell, Sam J; Schulz, Michael D; Wagener, Kenneth B; Batich, Christopher D; Milner, Rowan J; Lagmay, Joanne; Bolch, Wesley E

    2014-09-01

    Discussed in detail is the synthesis and primary structure characterization of two polymers aimed at advancing the treatment of pediatric osteosarcoma. These polymers are designed to systemically deliver radiometals specifically to osteosarcomas using the passive targeting mechanism of enhanced permeability and retention (the EPR effect). The approach begins with the synthesis of a polymer capable of binding radiometals, for which prior data show improved site-specific targeting of solid tumors. Building on this success, a second polymer has been designed for improving the efficacy of currently available radionuclide therapies by incorporating the FDA-approved small-molecule ligand Quadramet directly onto the polymer structure. Time-activity curves of the phosphonate-functionalized polymers show rapid clearance from the central compartment and nontargeted organs, with up to 65% of injected activity being excreted within 3 hours. Both polymer ligands demonstrate good osteosarcoma targeting capability with little to no uptake in organs associated with the dose-limiting bone marrow. Additionally, biodistribution studies in nonosseous tumor models demonstrate the tumor targeting mechanism of the polymer ligands, which appears to be influenced by the high affinity of the phosphonate functionality for the positively charged hydroxyapatite mineral found in bone tumors. PMID:25111903

  7. Thermodynamics and Phase Behavior of Phosphonated Block Copolymers Containing Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Jung, Ha Young; Park, Moon Jeong

    Charge-containing copolymers have drawn intensive attention in recent years for their uses in wide range of electrochemical devices such as fuel cells, lithium batteries and actuators. Particularly, the creation of microphase-separated morphologies in such materials by designing them in block and graft configurations has been the subject of extensive studies, in order to establish a synergistic means of optimizing ion transport properties and mechanical integrity. Interest in this topic has been further stimulated by intriguing phase behavior from charge-containing polymers, which was not projected from conventional phase diagrams of non-ionic polymers. Herein, we investigate thermodynamics and phase behavior of a set of phosphonated block copolymers. By synthesizing low-molecular weight samples with degree of polymerization (N) <35, we observed order-disorder transition that enabled us to estimate effective Flory-Huggins interaction parameters (χ) by using random phase approximation. We further examined the systems by adding various ionic liquids, where noticeable increases in χ values and modulated microphase separation behavior were observed. The morphology-conductivity relationship has been elucidated by taking into account the segmental motion of polymer chains, volume of conducting phases, and the molecular interactions between phosphonated polymer chains and cations of ionic liquids.

  8. Phosphonic pseudopeptides as human neutrophil elastase inhibitors--a combinatorial approach.

    PubMed

    Sieńczyk, Marcin; Podgórski, Dawid; Błażejewska, Aleksandra; Kulbacka, Julita; Saczko, Jolanta; Oleksyszyn, Józef

    2011-02-01

    Here we present a simple and rapid method for the construction of phosphonic peptide mimetic inhibitor libraries-products of Ugi and Passerini multicomponent condensations-leading to the selection of new biologically active phosphonic pseudopeptides. As the starting isonitriles, 1-isocyanoalkylphosphonate diaryl ester derivatives were applied. The structure of the synthesized inhibitors was designed to target human neutrophil elastase, a serine protease whose uncontrolled activity may lead to development of several pathophysiological states such as rheumatoid arthritis, cystic fibrosis or tumor growth and invasion. After screening the inhibitory activity of our constructed libraries, the most active compounds were synthesized as single molecules. One of the obtained inhibitors, Cbz-Met-O-Met-Val(P)(OC(6)H(4)-p-Cl)(2), displayed apparent second-order inhibition value at 40,105M(-1)s(-1) as the diastereomers mixture. Inhibition potency and selectivity of action toward other serine proteases as well as the results of initial in vitro experiments regarding inhibitors influence on cancer cell proliferation are presented. PMID:21216608

  9. Phosphonic drugs: Experimental and theoretical spectroscopic studies of fosfomycin

    NASA Astrophysics Data System (ADS)

    Chruszcz-Lipska, Katarzyna; Zborowski, Krzysztof K.; Podstawka-Proniewicz, Edyta; Liu, Shaoxuan; Xu, Yizhuang; Proniewicz, Leonard M.

    2011-02-01

    pH and time-dependant changes of fosfomycin molecular structure in an aqueous solution are studied by Raman, NMR, and generalized 2D correlation spectroscopies. Interpretation of the experimental spectra is based on the assumption of formation of different species running on applied physicochemical conditions. Geometries of all possible structures were entirely optimized with the 6-311++G(2df,p) basis set at the B3LYP theoretical level using procedures implemented in the Gaussian '03 set of programs. Harmonic frequency calculations verified the nature of the studied structures and allowed to simulate obtained Raman spectra. The theoretical NMR shielding was calculated using the GIAO method at the same computational level. In addition, in some cases PCM model was used to monitor the influence of water molecules on the NMR spectra. It is shown that in the pH range of 1-2 of fosfomycin aqueous solution oxirane ring is open sequent to nucleophilic attack and forms 1,2-dihydroxyphosphonic acid with small content of its monodeprotonated species. On the other hand, in pH 7 and higher it appears either as 1,2-epoxypropylphosphonic or 1,2-dihydroxyphosphonic dianion depending upon whether hydrolysis took place or not. It is also discussed that Raman marker bands originating from the individual species of fosfomycin can be used to detect and/or to monitor this antibiotic in an aqueous medium (for example urine samples). Hence, depending upon the structure found in urine one can tell about metabolic processes of this antibiotic in the body.

  10. Chiral Brønsted Acid Catalyzed Enantioselective Phosphonylation of Allylamine via Oxidative Dehydrogenation Coupling.

    PubMed

    Cheng, Ming-Xing; Ma, Ran-Song; Yang, Qiang; Yang, Shang-Dong

    2016-07-01

    A new strategy for the synthesis of chiral α-amino phosphonates by enantioselective C-H phosphonylation of allylamine with phosphite in the presence of a chiral Brønsted acid catalyst has been developed. This protocol successfully integrates direct C-H oxidation with asymmetric phosphonylation and exhibits high enantioselectivity. PMID:27331612

  11. Spectroscopic and theoretical studies of some N , N -diethyl-2-[(4‧-substituted)phenylsulfonyl]acetamides

    NASA Astrophysics Data System (ADS)

    Vinhato, Elisângela; Olivato, Paulo R.; Rodrigues, Alessandro; Zukerman-Schpector, Julio; Colle, Maurizio Dal

    2011-09-01

    The analysis of the IR carbonyl band of the N, N-diethyl-2-[(4'-substituted)phenylsulfonyl]acetamides Et 2NC(O)CH 2S(O) 2sbnd C 6H 4sbnd Y (Y = OMe 1, Me 2, H 3, Cl 4, Br 5, NO 26) supported by B3LYP/6-31G(d,p) calculations for 3, indicated the existence of three pairs ( anti and syn) of cis ( c) and gauche ( g1 and g2) conformers in the gas phase, being the gauche conformers significantly more stable than the cis ones. The anti geometry is more stable than the syn one, for each pair of cis and gauche conformers. The summing up of the orbital (NBO analysis) and electrostatic interactions justifies quite well the populations and the νCO frequencies of the anti and syn pairs of c, g1 and g2 conformers. The IR higher carbonyl frequency component whose population is ca. 10%, in CCl 4, may be ascribed to the least stable and most polar cis conformer pair (in the gas phase) and the lower frequency component whose population is ca. 90%, to the summing up of the populations of the two most stable and least polar gauche conformer pairs ( g1 and g2) (in the gas phase). The reversal of the cis( c)/ gauche ( g1 + g2) population ratio observed in chloroform ca. 60% ( cis)/40% ( gauche) and the occurrence of the most polar cis( c) conformer only, in acetonitrile, strongly suggests the coalescence of the two gauche components in a unique carbonyl band in solution. A further support to this rationalization is given by the single point PCM solvation model performed by HF/6-31G(d,p) method, which showed a progressive increase of the c/( g1 + g2) ratio going from gas to CCl 4, to CHCl 3 and to CH 3CN. X-ray single crystal analysis of 4 indicates that this compound assumes, in the solid state, the syn-clinal ( gauche) conformation with respect to the [O dbnd C sbnd CH 2sbnd S] moiety, and the most stable anti geometry relative to the [C(O)N(CH 2CH 3) 2] fragment. In order to obtain larger energy gain from the crystal packing the molecules of 4 are linked in centrosymmetric dimers

  12. Simultaneous analysis of biologically active aminoalkanephosphonic acids.

    PubMed

    Kudzin, Zbigniew H; Gralak, Dorota K; Andrijewski, Grzegorz; Drabowicz, Józef; Luczak, Jerzy

    2003-05-23

    A new approach for simultaneous analysis of biologically active aminoalkanephosphonic acids, namely glyphosate, phosphonoglycine, phosphonosarcosine, phosphonoalanine, phosphono-beta-alanine, phosphonohomoalanine, phosphono-gamma-homoalanine and glufosinate, is presented. This includes a preliminary 31p NMR analysis of these amino acids, their further derivatization to volatile phosphonates (phosphinates) by means of trifluoroacetic acid-trifluoroacetic anhydride-trimethyl orthoacetate reagent and subsequent analysis of derivatization products using MS and/or GC-MS (chemical ionization and/or electron impact ionization). PMID:12862383

  13. Practical and Efficient Synthesis of α-Aminophosphonic Acids Containing 1,2,3,4-Tetrahydroquinoline or 1,2,3,4-Tetrahydroisoquinoline Heterocycles.

    PubMed

    Ordóñez, Mario; Arizpe, Alicia; Sayago, Fracisco J; Jiménez, Ana I; Cativiela, Carlos

    2016-01-01

    We report here a practical and efficient synthesis of α-aminophosphonic acid incorporated into 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroisoquinoline heterocycles, which could be considered to be conformationally constrained analogues of pipecolic acid. The principal contribution of this synthesis is the introduction of the phosphonate group in the N-acyliminium ion intermediates, obtained from activation of the quinoline and isoquinoline heterocycles or from the appropriate δ-lactam with benzyl chloroformate. Finally, the hydrolysis of phosphonate moiety with simultaneous cleavage of the carbamate afforded the target compounds. PMID:27589713

  14. The nomenclature of 1-aminoalkylphosphonic acids and derivatives: evolution of the code system.

    PubMed

    Drabowicz, Józef; Jakubowski, Hieronim; Kudzin, Marcin H; Kudzin, Zbigniew H

    2015-01-01

    The approach for the unification of published proposals for the nomenclature and abbreviations of aminoalkylphosphonic acids and their derivatives is presented. Their modification was made on the basis of the IUPAC-IUB rules concerning the nomenclature and code system of proteinogenic amino acids. Our present proposal formulates the supplementary code and nomenclature system allowing unambiguous description of phosphonic analogs of proteinogenic amino acids, their analogs, homologs, metabolites, and derivatives including phosphonopeptides. PMID:25730210

  15. Microwave assisted rapid synthesis of N-methylene phosphonic chitosan via Mannich-type reaction.

    PubMed

    Dadhich, Prabhash; Das, Bodhisatwa; Dhara, Santanu

    2015-11-20

    Bio-conjugation or functional group substitutions are well-explored methods to enhance the physico-chemical and biochemical functionality of chitosan. N-Methylene phosphonic chitosan (NMPC) is one of the major substituted forms of chitosan, which has significant bioactivity and promising biomedical application. However, the reported synthesis methods of NMPC have limitations alike poor yield, higher degradation rate and most importantly long synthesis time (∼14h). In the current study, rapid synthesis of NMPC via a Mannich type reaction route using microwave irradiation has been reported. This method of NMPC synthesis offers significantly less synthesis time with competitive product yield. Synthesized NMPC was characterized via NMR, FTIR, EDS, XRD and thermal analysis. Further, viscosity average molecular weight, solubility, and conductivity of the substituted polymer were measured. Preliminary cyto-compatibility results of synthesized NMPC were promising for further exploration in biomedical applications. PMID:26344290

  16. Syntheses, spectroscopic properties and stereochemistry of bis-C-pivot macrocycles with two dialkyl phosphonate groups

    NASA Astrophysics Data System (ADS)

    Bilge, Selen; Kılıç, Zeynel; Davies, David B.

    2011-10-01

    Bis-C-pivot macrocycles containing dimethyl ( 1a, 2a) or diethyl phosphonate ( 1b, 2b) groups have been prepared by adding dimethyl or diethyl phosphite to two -CH dbnd N bonds in corresponding dibenzo-bis-imino crown ethers ( 1 and 2). Bis-C-pivot macrocycles possess two equivalent stereogenic centres giving rise to diastereoisomers ( meso and racemate). The structures were characterized by elemental analysis, FTIR, MS, TGA, DSC and NMR measurements. 1H, 13C and 31P NMR assignments were made for the isolated meso form of compounds 2a and 2b and for the meso and racemic forms of compounds 1a and 1b by analysis of chemical shifts, signal intensities and splitting patterns and the DEPT and 2D HETCOR NMR techniques. Thermal analysis and 1H NMR showed that the crystallised form of compound 1a contained an equimolar amount of water of crystallisation.

  17. N-Branched acyclic nucleoside phosphonates as monomers for the synthesis of modified oligonucleotides.

    PubMed

    Hocková, Dana; Rosenbergová, Šárka; Ménová, Petra; Páv, Ondřej; Pohl, Radek; Novák, Pavel; Rosenberg, Ivan

    2015-04-21

    Protected N-branched nucleoside phosphonates containing adenine and thymine bases were prepared as the monomers for the introduction of aza-acyclic nucleotide units into modified oligonucleotides. The phosphotriester and phosphoramidite methods were used for the incorporation of modified and natural units, respectively. The solid phase synthesis of a series of nonamers containing one central modified unit was successfully performed in both 3'→5' and 5'→3' directions. Hybridization properties of the prepared oligoribonucleotides and oligodeoxyribonucleotides were evaluated. The measurement of thermal characteristics of the complexes of modified nonamers with the complementary strand revealed a considerable destabilizing effect of the introduced units. We also examined the substrate/inhibitory properties of aza-acyclic nucleoside phosphono-diphosphate derivatives (analogues of nucleoside triphosphates) but neither inhibition of human and bacterial DNA polymerases nor polymerase-mediated incorporation of these triphosphate analogues into short DNA was observed. PMID:25766752

  18. Synthesis, Cytotoxicity, DNA Binding and Apoptosis of Rhein-Phosphonate Derivatives as Antitumor Agents

    PubMed Central

    Ye, Man-Yi; Yao, Gui-Yang; Wei, Jing-Chen; Pan, Ying-Ming; Liao, Zhi-Xin; Wang, Heng-Shan

    2013-01-01

    Several rhein-phosphonate derivatives (5a–c) were synthesized and evaluated for in vitro cytotoxicity against HepG-2, CNE, Spca-2, Hela and Hct-116 cell lines. Some compounds showed relatively high cytotoxicity. Especially compounds 5b exhibited the strongest cytotoxicity against HepG-2 and Spca-2 cells (IC50 was 8.82 and 9.01 μM), respectively. All the synthesized compounds exhibited low cytotoxicity against HUVEC cells. Further experiments proved that 5b could disturb the cell cycle in HepG-2 cells and induce apoptosis. In addition, the binding properties of a model conjugate 5b to DNA were investigated by methods (UV-Vis, fluorescence, CD spectroscopy). Results indicated that 5b showed moderate ability to interact ct-DNA. PMID:23629673

  19. Isotopic Measurements of Sulphonates and Phosphonates and Investigations of Possible Formaldehyde Products from the Murchison Meteorite

    NASA Technical Reports Server (NTRS)

    Cooper, George

    1996-01-01

    Intramolecular carbon, hydrogen, and sulfur isotope measurements have been made on a homologous series of organic sulfonates discovered in the Murchison meteorite. Mass independent sulfur isotope fractionations were observed along with D/H ratios clearly larger than terrestrial. The sulfur fractionations may be produced chemically and due to molecular symmetry factors. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low temperature astrophysical environment consistent with that of molecular clouds. The source of the sulfonate precursors may have been the reactive interstellar molecule, CS. Low temperature CS reactions also produce other sulfur containing compounds as well as a solid phase. Isotopic measurements on bulk phosphonates were also made.

  20. Tunable thermal and flame response of phosphonated oligoallylamines layer by layer assemblies on cotton.

    PubMed

    Carosio, Federico; Negrell-Guirao, Claire; Di Blasio, Alessandro; Alongi, Jenny; David, Ghislain; Camino, Giovanni

    2015-01-22

    In the present paper we have demonstrated how the change of the layer by layer deposition parameters can influence the final properties of cotton fabrics in terms of coating morphology, thermal stability and flammability. To this aim, novel synthetized oligoallylamines and phosphonated oligoallylamines have been assembled on the surface of cotton exploiting different molecular weights and pH conditions. Low molecular weights have yielded an incomplete "island growth" coating while high molecular weight resulted in a homogeneous coating which thickness was controlled by the adopted pH. Both low and high molecular weight assemblies induced a reduction of the cellulose decomposition temperatures that was, conversely, delayed by coatings assembled at pH=10. All assemblies were able to improve cotton flammability by suppressing the afterglow phenomenon; the best results in terms of flame spread and final residue have been achieved by high molecular weight assemblies. PMID:25439958

  1. Acyclic Immucillin Phosphonates. Second-Generation Inhibitors of Plasmodium falciparum Hypoxanthine- Guanine-Xanthine Phosphoribosyltransferase

    SciTech Connect

    Hazelton, Keith Z.; Ho, Meng-Chaio; Cassera, Maria B.; Clinch, Keith; Crump, Douglas R.; Rosario Jr., Irving; Merino, Emilio F.; Almo, Steve C.; Tyler, Peter C.; Schramm, Vern L.

    2012-06-22

    We found that Plasmodium falciparum is the primary cause of deaths from malaria. It is a purine auxotroph and relies on hypoxanthine salvage from the host purine pool. Purine starvation as an antimalarial target has been validated by inhibition of purine nucleoside phosphorylase. Hypoxanthine depletion kills Plasmodium falciparum in cell culture and in Aotus monkey infections. Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT) from P. falciparum is required for hypoxanthine salvage by forming inosine 5'-monophosphate, a branchpoint for all purine nucleotide synthesis in the parasite. We present a class of HGXPRT inhibitors, the acyclic immucillin phosphonates (AIPs), and cell permeable AIP prodrugs. The AIPs are simple, potent, selective, and biologically stable inhibitors. The AIP prodrugs block proliferation of cultured parasites by inhibiting the incorporation of hypoxanthine into the parasite nucleotide pool and validates HGXPRT as a target in malaria.

  2. Survey of organic acid eluents for anion chromatography

    SciTech Connect

    Book, D.E.

    1981-10-01

    Of all the potential eluents surveyed (including aromatic, sulfonic, phosphonic, among other acids), only the carboxylic acids and the nitrophenols are recommended as eluents for anion chromatography. The concentration of the eluent should be in the range 5 x 10/sup -5/ to 1 x 10/sup -3/ M. The eluent should have the same charge as inorganic anions, a higher charge than organic acid samples. Choice of eluents for separation of halides, chloride and sulfate, multivalent inorganic anions, small alkyl acids, and aromatic acids is discussed. (DLC)

  3. Pharmaceutical and clinical development of phosphonate-based radiopharmaceuticals for the targeted treatment of bone metastases.

    PubMed

    Lange, Rogier; Ter Heine, Rob; Knapp, Russ Ff; de Klerk, John M H; Bloemendal, Haiko J; Hendrikse, N Harry

    2016-10-01

    Therapeutic phosphonate-based radiopharmaceuticals radiolabeled with beta, alpha and conversion electron emitting radioisotopes have been investigated for the targeted treatment of painful bone metastases for >35years. We performed a systematic literature search and focused on the pharmaceutical development, preclinical research and early human studies of these radiopharmaceuticals. The characteristics of an ideal bone-targeting therapeutic radiopharmaceutical are presented and compliance with these criteria by the compounds discussed is verified. The importance of both composition and preparation conditions for the stability and biodistribution of several agents is discussed. Very few studies have described the characterization of these products, although knowledge on the molecular structure is important with respect to in vivo behavior. This review discusses a total of 91 phosphonate-based therapeutic radiopharmaceuticals, of which only six agents have progressed to clinical use. Extensive clinical studies have only been described for (186)Re-HEDP, (188)Re-HEDP and (153)Sm-EDTMP. Of these, (153)Sm-EDTMP represents the only compound with worldwide marketing authorization. (177)Lu-EDTMP has recently received approval for clinical use in India. This review illustrates that a thorough understanding of the radiochemistry of these agents is required to design simple and robust preparation and quality control methods, which are needed to fully exploit the potential benefits of these theranostic radiopharmaceuticals. Extensive biodistribution and dosimetry studies are indispensable to provide the portfolios that are required for assessment before human administration is possible. Use of the existing knowledge collected in this review should guide future research efforts and may lead to the approval of new promising agents. PMID:27496068

  4. Synthesis and biological properties of prodrugs of (S)-3-(adenin-9-yl)-2-(phosphonomethoxy)propanoic acid.

    PubMed

    Kaiser, Martin Maxmilian; Poštová-Slavětínská, Lenka; Dračínský, Martin; Lee, Yu-Jen; Tian, Yang; Janeba, Zlatko

    2016-01-27

    The lack of antiviral activity of recently described (S)-3-(adenin-9-yl)-2-(phosphonomethoxy)propanoic acid, or (S)-CPMEA in brief, has been speculated to possibly be due to the increased hydrophilicity of the molecule and, thus, by its limited cellular permeability. Efficient syntheses of novel lipophilic prodrugs of (S)-CPMEA masking either the carboxylic group or preferably both the phosphonate and carboxylic moieties, have been developed in order to increase bioavailability of the parent compound. Two prodrugs of (S)-CPMEA, namely phosphonate bis-amidate 15 and phenyloxy amidate 16, exhibited pan-genotypic anti-HCV activity at submicromolar concentrations. PMID:26706348

  5. Synthesis of the Sulphonate and Phosphonate Derivatives of Mercaptoacetyltriglycine. X-Ray Crystal Structure of Na2[ReO(Mercaptoacetylglycylglycylaminomethanesulphonate)]·3H2O

    PubMed Central

    Taylor, Andrew; Marzilli, Luigi G.

    1994-01-01

    Mercaptoacetyltriglycine forms complexes with 186/188Re and 99mTc radionuclides that are useful in nuclear medicine because they are substrates of the renal anion transport system. However, the renal clearance of [MO(MAG3)]2-(MAG3 = penta-anionic form of mercaptoacetyltriglycine, M = Re, Tc) complexes are less than ideal. Organic sulphonates are also transported by the renal anion transport system and phosphonates are similar to sulphonates in size and shape. In an effort to develop new ligands that form Re and Tc complexes and have improved renal clearances compared to [MO(MAG3)]2- complexes, the sulphonate and phosphonate derivatives of mercaptoacetyltriglycine were synthesized. The dianion [ReO(MAG2-AMS)]2- (MAG2-AMS = penta-anionic form of mercaptoacetylglycylglycylaminomethanesulphonic acid) was prepared for characterization by exchange reaction of ReOCl3(Me2S)(OPPh3) and isolated as the disodium salt. The structure of Na2[ReO(MAG2-AMS)]·3H2O (6) was determined by X-ray diffraction. The coordination geometry is pseudo square pyramidal, with the nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The deprotonated sulphonate group has a syn conformation with respect to the oxo ligand. The renal clearances of [99mTcO(MAG2-AMS)]2- and [99mTcO(MAG2-AMP)]3- were similar in rats and suggest that the difference in total charge between the SO3- and PO32- groups is not important to renal clearance. However, their renal clearances were 40-50% less than that of [99mTcO(MAG3)]2- suggesting that the size and shape of the large tetrahedral SO3- and PO32- groups of [99mTcO(MAG2-AMS)]2- and [99mTcO(MAG2-AMP)]3- inhibit recognition by the renal transport system compared to the small planar CO2- group of [99mTcO(MAG3)]2-. PMID:18476215

  6. The Anti-Inflammatory Activity of a Novel Fused-Cyclopentenone Phosphonate and Its Potential in the Local Treatment of Experimental Colitis

    PubMed Central

    Shifrin, Helena; Harel, Efrat; Nadler-Milbauer, Mirela; Weinstock, Marta; Srebnik, Morris

    2015-01-01

    A novel fused-cyclopentenone phosphonate compound, namely, diethyl 3-nonyl-5-oxo-3,5,6,6a-tetrahydro-1H-cyclopenta[c]furan-4-ylphosphonate (P-5), was prepared and tested in vitro (LPS-activated macrophages) for its cytotoxicity and anti-inflammatory activity and in vivo (DNBS induced rat model) for its potential to ameliorate induced colitis. Specifically, the competence of P-5 to reduce TNFα, IL-6, INFγ, MCP-1, IL-1α, MIP-1α, and RANTES in LPS-activated macrophages was measured. Experimental colitis was quantified in the rat model, macroscopically and by measuring the activity of tissue MPO and iNOS and levels of TNFα and IL-1β. It was found that P-5 decreased the levels of TNFα and the tested proinflammatory cytokines and chemokines in LPS-activated macrophages. In the colitis-induced rat model, P-5 was effective locally in reducing mucosal inflammation. This activity was equal to the activity of local treatment with 5-aminosalicylic acid. It is speculated that P-5 may be used for the local treatment of IBD (e.g., with the aid of colon-specific drug platforms). Its mode of action involves inhibition of the phosphorylation of MAPK ERK but not of p38 and had no effect on IκBα. PMID:25949237

  7. Exploring the role of the α-carboxyphosphonate moiety in the HIV-RT activity of α-carboxy nucleoside phosphonates

    PubMed Central

    Mullins, Nicholas D.; Maguire, Nuala M.; Ford, Alan; Das, Kalyan; Arnold, Edward; Balzarini, Jan; Maguire, Anita R.

    2016-01-01

    As α-carboxy nucleoside phosphonates (α-CNPs) have demonstrated a novel mode of action of HIV-1 reverse transcriptase inhibition, structurally related derivatives were synthesized, namely the malonate 2, the unsaturated and saturated bisphosphonates 3 and 4, respectively and the amide 5. These compounds were evaluated for inhibition of HIV-1 reverse transcriptase in cell-free assays. The importance of the α-carboxy phosphonoacetic acid moiety for achieving reverse transcriptase inhibition, without the need for prior phosphorylation, was confirmed. The malonate derivative 2 was less active by two orders of magnitude than the original α-CNPs, while displaying the same pattern of kinetic behavior; interestingly the activity resides in the “L”-enantiomer of 2, as seen with the earlier series of α-CNPs. A crystal structure with an RT/DNA complex at 2.95 Å resolution revealed the binding of the “L”-enantiomer of 2, at the polymerase active site with a weaker metal ion chelation environment compared to 1a (T-α-CNP) which may explain the lower inhibitory activity of 2. PMID:26813581

  8. Functionalized phosphonates as building units for multi-dimensional homo- and heterometallic 3d-4f inorganic-organic hybrid-materials.

    PubMed

    Köhler, C; Rentschler, E

    2016-08-01

    Using the multifunctional ligand H4L (2,2'-bipyridinyl-5,5'-diphosphonic acid), a new family of inorganic-organic hybrid-materials was prepared. The ligand shows a very high flexibility regarding the coordination mode, leading to a large structural diversity. The compounds 1a, 1b ([M(H2L)(H2O)4]·2.5H2O; M = Co(2+) (a), Ni(2+) (b)), 2 ([Gd2(H2H'L)2(H2H'2L)(H2O)6]Cl4·14H2O), 3a, 3b, 3c ([MCo(iii)(H2L)3(H2O)2]·6.5H2O; M = Gd(3+) (a), Dy(3+) (b) and Tb(3+) (c)), and 4 ([GdNi(ii)(H2L)3(H2O)3]NaCl·6H2O) were isolated and characterized with single crystal X-ray diffraction. Depending on the used metal ions and on the stoichiometry, either discrete entities (0D), extended 2D layers or 3D frameworks were obtained. In contrast to the general approach in phosphonate chemistry, the compounds were prepared without hydrothermal synthesis, but under ambient pressure. Variable temperature magnetic measurements were carried out to determine the magnetic properties. PMID:27472248

  9. Inhibition of alanine racemase by alanine phosphonate: detection of an imine linkage to pyridoxal 5'-phosphate in the enzyme-inhibitor complex by solid-state /sup 15/N nuclear magnetic resonance

    SciTech Connect

    Copie, V.; Faraci, W.S.; Walsh, C.T.; Griffin, R.G.

    1988-07-12

    Inhibition of alanine racemase from the Gram-positive bacterium Bacillus stearothermophilus by (1-aminoethyl)phosphonic acid (Ala-P) proceeds via a two-step reaction pathway in which reactivation occurs very slowly. In order to determine the mechanism of inhibition, the authors have recorded low-temperature, solid-state /sup 15/N NMR spectra from microcrystals of the (/sup 15/N)Ala-P-enzyme complex, together with spectra of a series of model compounds that provide the requisite database for the interpretation of the /sup 15/N chemical shifts. Proton-decoupled spectra of the microcrystals exhibit a line at approx. 150 ppm, which conclusively demonstrates the presence of a protonated Ala-P-PLP aldimine and thus clarifies the structure of the enzyme-inhibitor complex. They also report the pH dependence of Ala-P binding to alanine racemase.

  10. Bis{N-[bis­(pyrrolidin-1-yl)phosphor­yl]-2,2,2-trichloro­acetamide}di­nitrato­dioxidouranium(VI)

    PubMed Central

    Znovjyak, Kateryna O.; Ovchynnikov, Vladimir A.; Moroz, Olesia V.; Shishkina, Svitlana V.; Amirkhanov, Vladimir M.

    2010-01-01

    The crystal structure of the title compound, [U(NO3)2O2(C10H17Cl3N3O2P)2], is composed of centrosymmetric [UO2(L)2(NO3)2] mol­ecules {L is N-[bis­(pyrrolidin-1-yl)phosphor­yl]-2,2,2-trichloro­acetamide, C10H17Cl3N3O2P}. The UVI ion, located on an inversion center, is eight-coordinated with axial oxido ligands and six equatorial oxygen atoms of the phosphoryl and nitrate groups in a slightly distorted hexa­gonal-bipyramidal geometry. One of the pyrrolidine fragments in the ligand is disordered over two conformation (occupancy ratio 0.58:0.42). Intra­molecular N—H⋯O hydrogen bonds between the amine and nitrate groups are found. PMID:21580260

  11. A novel 2-(2-Formyl-4-methyl-phenoxy)-N-phenyl-acetamide-based fluorescence turn-on chemosensor for selenium determination with high selectivity and sensitivity

    NASA Astrophysics Data System (ADS)

    Song, Cairui; Fei, Qiang; Shan, Hongyan; Feng, Guodong; Cui, Minghui; Liu, Yameng; Huan, Yanfu

    2013-12-01

    A novel turn-on fluorescent chemosensor, 2-(2-Formyl-4-methyl-phenoxy)-N-phenyl-acetamide (FMPPA) was designed and synthesized, and its photophysical properties were characterized. Upon coordination with Se (IV), the chemosensor showed incredible fluorescence enhancement (turn-on), other alkali, alkaline earth, transitional metal ions, and common anions including Li+, Na+, K+, Rb+, Cs+, Be2+, Mg2+, Ca2+, Sr2+, Ba2+, Ni2+, Cu2+, Cd2+, Zn2+, Mn2+, As3+, Pt4+, V5+, Fe3+, Mo6+, Al3+, CO32-, Cl-, SCN-, AC-, NO3-, F-, SO42- had no significant interference on Se (IV) determination. The chemosensor exhibits a dynamic response range for Se (IV) from 3.32 × 10-7 to 2.63 × 10-6 M, with a detection limit of 9.38 × 10-9 M (3σ).

  12. SBA-15 mesoporous silica free-standing thin films containing copper ions bounded via propyl phosphonate units - preparation and characterization

    NASA Astrophysics Data System (ADS)

    Laskowski, Lukasz; Laskowska, Magdalena; Jelonkiewicz, Jerzy; Dulski, Mateusz; Wojtyniak, Marcin; Fitta, Magdalena; Balanda, Maria

    2016-09-01

    The SBA-15 silica thin films containing copper ions anchored inside channels via propyl phosphonate groups are investigated. Such materials were prepared in the form of thin films, with hexagonally arranged pores, laying rectilinear to the substrate surface. However, in the case of our thin films, their free standing form allowed for additional research possibilities, that are not obtainable for typical thin films on a substrate. The structural properties of the samples were investigated by X-ray reflectometry, atomic force microscopy (AFM) and transmission electron microscopy (TEM). The molecular structure was examined by Raman spectroscopy supported by numerical simulations. Magnetic measurements (SQUID magnetometry and EPR spectroscopy) showed weak antiferromagnetic interactions between active units inside silica channels. Consequently, the pores arrangement was determined and the process of copper ions anchoring by propyl phosphonate groups was verified in unambiguous way. Moreover, the type of interactions between magnetic atoms was determined.

  13. Structure and Mechanism of Enzymes Involved in Biosynthesis and Breakdown of the Phosphonates Fosfomycin, Dehydrophos, and Phosphinothricin

    PubMed Central

    Nair, Satish K.; van der Donk, Wilfred A.

    2011-01-01

    Recent years have seen a rapid increase in the mechanistic and structural information on enzymes that are involved in the biosynthesis and breakdown of naturally occurring phosphonates. This review focuses on these recent developments with an emphasis on those enzymes that have been characterized crystallographically in the past five years, including proteins involved in the biosynthesis of phosphinothricin, fosfomycin, and dehydrophos and proteins involved in resistance mechanisms. PMID:20854789

  14. Synthesis and kinetic evaluation of Cyclophostin and Cyclipostins phosphonate analogs as selective and potent inhibitors of microbial lipases

    PubMed Central

    Point, Vanessa; Malla, Raj K.; Diomande, Sadia; Martin, Benjamin P.; Delorme, Vincent; Carriere, Frederic; Canaan, Stephane; Rath, Nigam P.; Spilling, Christopher D.; Cavalier, Jean-François

    2012-01-01

    New series of customizable diastereomeric cis- and trans-monocyclic enol-phosphonate analogs to Cyclophostin and Cyclipostins were synthesized. Their potencies and mechanisms of inhibition toward six representative lipolytic enzymes belonging to distinct lipase families were examined. With mammalian gastric and pancreatic lipases no inhibition occurred with any of the compounds tested. Conversely, Fusarium solani Cutinase and lipases from Mycobacterium tuberculosis (Rv0183 and LipY) were all fully inactivated. Best inhibitors displayed a cis conformation (H and OMe) and exhibited higher inhibitory activities than the lipase inhibitor Orlistat towards same enzymes. Our results have revealed that chemical group at the γ-carbon of the phosphonate ring strongly impacts the inhibitory efficiency, leading to a significant improvement in selectivity toward a target lipase over another. The powerful and selective inhibition of microbial (fungal and mycobacterial) lipases suggests that these 7-membered monocyclic enol-phosphonates should provide useful leads for the development of novel and highly selective antimicrobial agents. PMID:23095026

  15. On the question of stepwise vs. concerted cleavage of RNA models promoted by a synthetic dinuclear Zn(II) complex in methanol: implementation of a noncleavable phosphonate probe.

    PubMed

    Edwards, David R; Tsang, Wing-Yin; Neverov, Alexei A; Brown, R Stan

    2010-02-21

    To address the question of concerted versus a stepwise reaction mechanisms for the cyclization of the 2-hydroxypropyl aryl and alkyl RNA models (1a-k) promoted by dinuclear Zn(II) complex (4) at (s)spH 9.8 and 25 degrees C, the non-cleavable O-hydroxypropyl phenylphosphonate analogues 6a and 6b were subjected to the catalytic reaction in methanol. These phosphonates did not undergo isomerization in the study, the only observable methanolysis reaction being release of 1,2-propanediol and the formation of O-methyl phenylphosphonate. The observed first order rate constants for methanolysis promoted by 4 are k(obs)(6a) = (1.47 +/- 0.09) x 10(-4) s(-1) and k(obs)(6b) = (2.08 +/- 0.09) x 10(-6) s(-1), respectively. The rates of methanolysis of a series of O-aryl phenylphosphonates (8a-f) in the presence of increasing [4] were analyzed to provide binding constants, Kb, and the catalytic rate constant, kcat(max), for the unimolecular decomposition of the 8:4 Michaelis complex. A Brønsted plot of the log (k(cat)(max)) vs. sspKa(phenol) (acidity constant of the conjugate acid of the leaving group in methanol) was fitted to a linear regression of log kcat(max) = (-0.80 +/- 0.07)(s)spKa + (10.2 +/- 1.0) which includes the datum for 6a. The datum for 6b, which reacts approximately 70-fold slower, falls significantly below the linear correlation. The data provide additional evidence consistent with a concerted cyclization of RNA models 1a-k promoted by 4. PMID:20135039

  16. Structure Activity Relationship of (N)-Methanocarba Phosphonate Analogues of 5’-AMP as Cardioprotective Agents Acting Through a Cardiac P2X Receptor

    PubMed Central

    Kumar, T. Santhosh; Zhou, Si-Yuan; Joshi, Bhalchandra V.; Balasubramanian, Ramachandran; Yang, Tiehong; Liang, Bruce T.; Jacobson, Kenneth A.

    2010-01-01

    P2X receptor activation protects in heart failure models. MRS2339 3, a 2-chloro-AMP derivative containing a (N)-methanocarba (bicyclo[3.1.0]hexane) system, activates this cardioprotective channel. Michaelis–Arbuzov and Wittig reactions provided phosphonate analogues of 3, expected to be stable in vivo due to the C-P bond. After chronic administration via a mini-osmotic pump (Alzet), some analogues significantly increased intact heart contractile function in calsequestrin-overexpressing mice (genetic model of heart failure) compared to vehicle-infused mice (all inactive at the vasodilatory P2Y1 receptor). Two phosphonates, (1’S,2’R,3’S,4’R,5’S)-4’-(6-amino-2-chloropurin-9-yl)-2’,3’-(dihydroxy)-1’-(phosphonomethylene)-bicyclo[3.1.0]hexane 4 and its homologue 9, both 5’-saturated, containing a 2-Cl substitution, improved echocardiography-derived fractional shortening (20.25% and 19.26%, respectively, versus 13.78% in controls), while unsaturated 5’-extended phosphonates, all 2-H analogues, and a CH3-phosphonate were inactive. Thus, chronic administration of nucleotidase-resistant phosphonates conferred a beneficial effect, likely via cardiac P2X receptor activation. Thus, we have greatly expanded the range of carbocyclic nucleotide analogues that represent potential candidates for the treatment of heart failure. PMID:20192270

  17. Tribological behaviors of lanthanum-based phosphonate 3-aminopropyltriethoxysilane self-assembled films

    NASA Astrophysics Data System (ADS)

    Gu, Qinlin; Cheng, Xianhua

    2007-06-01

    Lanthanum-based thin films deposited on the phosphonate 3-aminopropyltriethoxysilane (APTES) self-assembled monolayer (SAM) were prepared on the hydroxylated glass substrate by a self-assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of the films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. As the results, the target film was obtained and reaction may have taken place between the film and the glass substrate. The tribological results show that lanthanum-based thin films are superior in reducing friction and resisting wear compared with APTES-SAM and phosphorylated APTES-SAM. SEM observation of the morphologies of worn surfaces indicates that the wear of APTES-SAM and the phosphorylated APTES-SAM is characteristic of brittle fracture and severe abrasion. Differently, slight abrasion and micro-crack dominate the wear of lanthanum-based thin films. The superior friction reduction and wear resistance of lanthanum-based thin films are attributed to the enhanced load-carrying capacity of the inorganic lanthanum particles in the lanthanum-based thin films as well as good adhesion of the films to the substrate.

  18. The inhibition of mitochondrial dicarboxylate transport by inorganic phosphate, some phosphate esters and some phosphonate compounds.

    PubMed

    Johnson, R N; Chappell, J B

    1974-02-01

    1. P(i) competitively inhibited succinate oxidation by intact uncoupled mitochondria in the presence of sufficient N-ethylmaleimide to block the phosphate carrier, with a K(i) of 2.5mm. 2. Of a large number of phosphate esters and phosphonate compounds, phenyl phosphate and phenylphosphonate were found to inhibit competitively uncoupled succinate oxidation by intact but not broken mitochondria. By comparison, benzoate was a relatively weak competitive inhibitor of succinate oxidation by intact mitochondria but a relatively potent inhibitor of succinate dehydrogenase. 3. Phenyl phosphate and phenylphosphonate were non-penetrant, and inhibited P(i)-dependent swelling of mitochondria suspended in isosmolar ammonium malate in a manner non-competitive with P(i). The inhibitors did not affect mitochondrial swelling when tested with P(i) alone. 4. It is concluded that: (i) phenyl phosphate and phenylphosphonate behaved as non-penetrant analogues of P(i), since their inhibitory properties were in strict contrast with those of benzoate; (ii) phenyl phosphate and phenylphosphonate interacted with the dicarboxylate carrier but not with the phosphate carrier; (iii) P(i) was effective as a competitive inhibitor of succinate oxidation because of its being either an alternative substrate for the dicarboxylate carrier or competitive with succinate for the intramitochondrial cations as proposed by Harris & Manger (1968). PMID:4822730

  19. Antiviral Activity and Mechanism of Action of Novel Thiourea Containing Chiral Phosphonate on Tobacco Mosaic Virus

    PubMed Central

    Fan, Huitao; Song, Baoan; Bhadury, Pinaki S.; Jin, Linhong; Hu, Deyu; Yang, Song

    2011-01-01

    Using half-leaf method O,O′-diisopropyl (3-(L-1-(benzylamino)-1-oxo-3- phenylpropan-2-yl)thioureido)(phenyl)methyl phosphonate (2009104) was studied for its activity on tobacco mosaic virus (TMV). It showed good curative activity in vivo and the curative activity at 500 μg/mL was found to be 53.3%. In vivo treatment with the control agent Ningnanmycin at 500 μg/mL resulted in 51.2% inhibition and curative inhibition rates respectively. Dot-ELISA test was employed to verify the efficacy of activity of compound 200910 for anti-TMV activity. The mechanism of action of compound 2009104 to resist TMV was also studied. The results showed that the resistance enzymes PAL, POD, SOD activity and chlorophyll content after TMV inoculation K326 (Nicotiana tabacum K326) of tobacco plants followed by treatment with compound 2009104 were significantly enhanced. The study of the effect of compound 2009104 on TMV capsid protein (CP) showed that it inhibited the polymerization process of TMV-CP in vitro. PMID:21845094

  20. Antiviral activity and mechanism of action of novel thiourea containing chiral phosphonate on tobacco mosaic virus.

    PubMed

    Fan, Huitao; Song, Baoan; Bhadury, Pinaki S; Jin, Linhong; Hu, Deyu; Yang, Song

    2011-01-01

    Using half-leaf method O,O'-diisopropyl (3-(L-1-(benzylamino)-1-oxo-3- phenylpropan-2-yl)thioureido)(phenyl)methyl phosphonate (2009104) was studied for its activity on tobacco mosaic virus (TMV). It showed good curative activity in vivo and the curative activity at 500 μg/mL was found to be 53.3%. In vivo treatment with the control agent Ningnanmycin at 500 μg/mL resulted in 51.2% inhibition and curative inhibition rates respectively. Dot-ELISA test was employed to verify the efficacy of activity of compound 200910 for anti-TMV activity. The mechanism of action of compound 2009104 to resist TMV was also studied. The results showed that the resistance enzymes PAL, POD, SOD activity and chlorophyll content after TMV inoculation K(326) (Nicotiana tabacum K(326)) of tobacco plants followed by treatment with compound 2009104 were significantly enhanced. The study of the effect of compound 2009104 on TMV capsid protein (CP) showed that it inhibited the polymerization process of TMV-CP in vitro. PMID:21845094

  1. High performance of phosphonate-functionalized mesoporous silica for U(VI) sorption from aqueous solution.

    PubMed

    Yuan, Li-Yong; Liu, Ya-Lan; Shi, Wei-Qun; Lv, Yu-Long; Lan, Jian-Hui; Zhao, Yu-Liang; Chai, Zhi-Fang

    2011-07-28

    The renaissance of nuclear energy promotes increasing basic research on the separation and enrichment of nuclear fuel associated radionuclides. Herein, we report the first study for developing mesoporous silica functionalized with phosphonate (NP10) as a sorbent for U(VI) sorption from aqueous solution. The mesoporous silica was synthesized by co-condensation of diethylphosphatoethyltriethoxysilane (DPTS) and tetraethoxysilane (TEOS), using cationic surfactant cetyltrimethylammonium bromide (CTAB) as the template. The synthesized silica nanoparticles were observed to possess a mesoporous structure with a uniform pore diameter of 2.7 nm, and to have good stability and high efficiency for U(VI) sorption from aqueous solution. A maximum sorption capacity of 303 mg g(-1) and fast equilibrium time of 30 min were achieved under near neutral conditions at room temperature. The adsorbed U(VI) can be easily desorbed by using 0.1 mol L(-1) HNO(3), and the reclaimed mesoporous silica can be reused with no decrease of sorption capacity. In addition, the preconcentration of U(VI) from a 100 mL aqueous solution using the functionalized mesoporous silica was also studied. The preconcentration factor was found to be as high as 100, suggesting the vast opportunities of this kind of mesoporous silica for the solid-phase extraction and enrichment of U(VI). PMID:21681327

  2. Modeling the time dependent biodistribution of Samarium-153 ethylenediamine tetramethylene phosphonate using compartmental analysis

    PubMed Central

    Abbasian, Parandoush; Foroghy, Monika; Jalilian, Amir Reza; Hakimi, Amir; Shirvani-Arani, Simindokht

    2013-01-01

    Aim The main purpose of this work was to develop a pharmacokinetic model for the bone pain palliation agent Samarium-153 ethylenediamine tetramethylene phosphonate ([153Sm]-EDTMP) in normal rats to analyze the behavior of the complex. Background The use of compartmental analysis allows a mathematical separation of tissues and organs to determine the concentration of activity in each fraction of interest. Biodistribution studies are expensive and difficult to carry out in humans, but such data can be obtained easily in rodents. Materials and methods We have developed a physiologically based pharmacokinetic model for scaling up activity concentration in each organ versus time. The mathematical model uses physiological parameters including organ volumes, blood flow rates, and vascular permabilities; the compartments (organs) are connected anatomically. This allows the use of scale-up techniques to predict new complex distribution in humans in each organ. Results The concentration of the radiopharmaceutical in various organs was measured at different times. The temporal behavior of biodistribution of 153Sm-EDTMP was modeled and drawn as a function of time. Conclusions The variation of pharmaceutical concentration in all organs is described with summation of 6–10 exponential terms and it approximates our experimental data with precision better than 2%. PMID:24936338

  3. Proton-Electron Double-Resonance Imaging of pH using phosphonated trityl probe

    PubMed Central

    Takahashi, Wataru; Bobko, Andrey A.; Dhimitruka, Ilirian; Hirata, Hiroshi; Zweier, Jay L.; Samouilov, Alexandre

    2014-01-01

    Variable Radio Frequency Proton-Electron Double-Resonance Imaging (VRF PEDRI) enables extracting a functional map from a limited number of images acquired at pre-selected EPR frequencies using specifically designed paramagnetic probes with high quality spatial resolution and short acquisition times. In this work we explored potential of VRF PEDRI for pH mapping of aqueous samples using recently synthesized pH-sensitive phosphonated trityl radical, pTR. The ratio of Overhauser enhancements measured at each pixel at two different excitation frequencies corresponding to the resonances of protonated and deprotonated forms of pTR probe allows for a pH map extraction. Long relaxation times of pTR allow for pH mapping at EPR irradiation power as low as 1.25 W during 130 s acquisition time with spatial resolution of about 1 mm. This is particularly important for in vivo applications enabling one to avoid sample overheating by reducing RF power deposition. PMID:25530673

  4. Ester prodrugs of acyclic nucleoside thiophosphonates compared to phosphonates: synthesis, antiviral activity and decomposition study.

    PubMed

    Roux, Loïc; Priet, Stéphane; Payrot, Nadine; Weck, Clément; Fournier, Maëlenn; Zoulim, Fabien; Balzarini, Jan; Canard, Bruno; Alvarez, Karine

    2013-05-01

    9-[2-(Thiophosphonomethoxy)ethyl]adenine [S-PMEA, 8] and (R)-9-[2-(Thiophosphonomethoxy)propyl]adenine [S-PMPA, 9] are acyclic nucleoside thiophosphonates we described recently that display the same antiviral spectrum (DNA viruses) as approved and potent phosphonates PMEA and (R)-PMPA. Here, we describe the synthesis, antiviral activities in infected cell cultures and decomposition study of bis(pivaloyloxymethoxy)-S-PMEA [Bis-POM-S-PMEA, 13] and bis(isopropyloxymethylcarbonyl)-S-PMPA [Bis-POC-S-PMPA, 14] as orally bioavailable prodrugs of the S-PMEA 8 and S-PMPA 9, in comparison to the equivalent "non-thio" derivatives [Bis-POM-PMEA, 11] and [Bis-POC-PMPA, 12]. Compounds 11, 12, 13 and 14 were evaluated for their in vitro antiviral activity against HIV-1-, HIV-2-, HBV- and a broad panel of DNA viruses, and found to exhibit moderate to potent antiviral activity. In order to determine the decomposition pathway of the prodrugs 11, 12, 13 and 14 into parent compounds PMEA, PMPA, 8 and 9, kinetic data and decomposition pathways in several media are presented. As expected, bis-POM-S-PMEA 13 and bis-POC-S-PMPA 14 behaved as prodrugs of S-PMEA 8 and S-PMPA 9. However, thiophosphonates 8 and 9 were released very smoothly in cell extracts, in contrast to the release of PMEA and PMPA from "non-thio" prodrugs 11 and 12. PMID:23603046

  5. Graphite-supported perchloric acid (HClO4-C): an efficient and recyclable heterogeneous catalyst for the one-pot synthesis of amidoalkyl naphthols.

    PubMed

    Lei, Zhen-Kai; Xiao, Li; Lu, Xiao-Quan; Huang, He; Liu, Chen-Jiang

    2013-01-01

    An efficient and direct protocol for the preparation of amidoalkylnaphthols employing a multi-component, one-pot condensation reaction of 2-naphthol, aromatic aldehydes and acetamide or benzamide in the presence of graphite supported perchloric acid under solvent-free conditions is described. The thermal solvent-free procedure offers advantages such as simple work-up, shorter reaction times and higher product yields, and the catalyst exhibited remarkable reactivity and can be recycled. PMID:23358323

  6. New spectrofluorimetric methods for determination of melatonin in the presence of N-{2-[1-({3-[2-(acetylamino)ethyl]-5-methoxy-1H-indol-2-yl}methyl)-5-methoxy-1H-indol-3-yl]- ethyl}acetamide: a contaminant in commercial melatonin preparations

    PubMed Central

    2012-01-01

    Background Melatonin (MLT) has many health implications, therefore it is of valuable importance to develop specific analytical methods for determination of MLT in the presence of its main contaminant, N-{2-[1-({3-[2-(acetylamino)ethyl]-5-methoxy-1H-indol-2-yl}methyl)-5-methoxy-1H-indol-3-yl]ethyl}acetamide (10). For development of these analytical methods, compound 10 had to be prepared in an adequate amount. Results Compound 10 was synthesized in six steps starting from 5-methoxyindole-2-carboxylic acid (1). Analytical performance of the proposed spectrofluorimetric methods was statistically validated with respect to linearity, accuracy, precision and specificity. The proposed methods were successfully applied for the assay of MLT in laboratory prepared mixtures containing up to 60 % of compound 10 and in commercial MLT tablets with recoveries not less than 99.00 %. No interference was observed from common pharmaceutical additives and the results were favorably compared with those obtained by a reference method. Conclusions This work describes simple, sensitive, and reliable second derivative spectrofluorimetric method in addition to two multivariate calibration methods, principal component regression (PCR) and partial least square (PLS), for the determination of MLT in the presence of compound 10. PMID:22551394

  7. Proton Conduction in a Phosphonate-Based Metal-Organic Framework Mediated by Intrinsic "Free Diffusion inside a Sphere".

    PubMed

    Pili, Simona; Argent, Stephen P; Morris, Christopher G; Rought, Peter; García-Sakai, Victoria; Silverwood, Ian P; Easun, Timothy L; Li, Ming; Warren, Mark R; Murray, Claire A; Tang, Chiu C; Yang, Sihai; Schröder, Martin

    2016-05-25

    Understanding the molecular mechanism of proton conduction is crucial for the design of new materials with improved conductivity. Quasi-elastic neutron scattering (QENS) has been used to probe the mechanism of proton diffusion within a new phosphonate-based metal-organic framework (MOF) material, MFM-500(Ni). QENS suggests that the proton conductivity (4.5 × 10(-4) S/cm at 98% relative humidity and 25 °C) of MFM-500(Ni) is mediated by intrinsic "free diffusion inside a sphere", representing the first example of such a mechanism observed in MOFs. PMID:27182787

  8. A Mixed-Valent Uranium Phosphonate Framework Containing U(IV) , U(V) , and U(VI).

    PubMed

    Chen, Lanhua; Zheng, Tao; Bao, Songsong; Zhang, Linjuan; Liu, Hsin-Kuan; Zheng, Limin; Wang, Jianqiang; Wang, Yaxing; Diwu, Juan; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

    2016-08-16

    It is shown that U(V) O2 (+) ions can reside at U(VI) O2 (2+) lattice sites during mild reduction and crystallization process under solvothermal conditions, yielding a complicated and rare mixed-valent uranium phosphonate compound that simultaneously contains U(IV) , U(V) , and U(VI) . The presence of uranium with three oxidation states was confirmed by various characterization techniques, including X-ray crystallography, X-ray photoelectron, electron paramagnetic resonance, FTIR, UV/Vis-NIR absorption, and synchrotron radiation X-ray absorption spectroscopy, and magnetism measurements. PMID:27356283

  9. Phosphorus Deprivation Responses and Phosphonate Utilization in a Thermophilic Synechococcus sp. from Microbial Mats▿ †

    PubMed Central

    Adams, Melissa M.; Gómez-García, María R.; Grossman, Arthur R.; Bhaya, Devaki

    2008-01-01

    The genomes of two closely related thermophilic cyanobacterial isolates, designated Synechococcus isolate OS-A and Synechococcus isolate OS-B′, from the microbial mats of Octopus Spring (Yellowstone National Park) have been sequenced. An extensive suite of genes that are controlled by phosphate levels constitute the putative Pho regulon in these cyanobacteria. We examined physiological responses of an axenic OS-B′ isolate as well as transcript abundances of Pho regulon genes as the cells acclimated to phosphorus-limiting conditions. Upon imposition of phosphorus deprivation, OS-B′ stopped dividing after three to four doublings, and absorbance spectra measurements indicated that the cells had lost most of their phycobiliproteins and chlorophyll a. Alkaline phosphatase activity peaked and remained high after 48 h of phosphorus starvation, and there was an accumulation of transcripts from putative Pho regulon genes. Interestingly, the genome of Synechococcus isolate OS-B′ harbors a cluster of phn genes that are not present in OS-A isolates. The proteins encoded by the phn genes function in the transport and metabolism of phosphonates, which could serve as an alternative phosphorus source when exogenous phosphate is low. The phn genes were upregulated within a day of eliminating the source of phosphate from the medium. However, the ability of OS-B′ to utilize methylphosphonate as a sole phosphorus source occurred only after an extensive period of exposure to the substrate. Once acclimated, the cells grew rapidly in fresh medium with methylphosphonate as the only source of phosphorus. The possible implications of these results are discussed with respect to the ecophysiology of the microbial mats. PMID:18931115

  10. Acetylcholinesterase active centre and gorge conformations analysed by combinatorial mutations and enantiomeric phosphonates.

    PubMed Central

    Kovarik, Zrinka; Radić, Zoran; Berman, Harvey A; Simeon-Rudolf, Vera; Reiner, Elsa; Taylor, Palmer

    2003-01-01

    A series of eight double and triple mutants of mouse acetylcholinesterase (AChE; EC 3.1.1.7), with substitutions corresponding to residues found largely within the butyrylcholinesterase (BChE; EC 3.1.1.8) active-centre gorge, was analysed to compare steady-state kinetic constants for substrate turnover and inhibition parameters for enantiomeric methylphosphonate esters. The mutations combined substitutions in the acyl pocket (Phe(295)-->Leu and Phe(297)-->Ile) with the choline-binding site (Tyr(337)-->Ala and Phe(338)-->Ala) and with a side chain (Glu(202)--> Gln) N-terminal to the active-site serine, Ser(203). The mutations affected catalysis by increasing K (m) and decreasing k (cat), but these constants were typically affected by an order of magnitude or less, a relatively small change compared with the catalytic potential of AChE. To analyse the constraints on stereoselective phosphonylation, the mutant enzymes were reacted with a congeneric series of S (P)- and R (P)-methylphosphonates of known absolute stereochemistry. Where possible, the overall reaction rates were deconstructed into the primary constants for formation of the reversible complex and intrinsic phosphonylation. The multiple mutations greatly reduced the reaction rates of the more reactive S (P)-methylphosphonates, whereas the rates of reaction with the R (P)-methylphosphonates were markedly enhanced. With the phosphonates of larger steric bulk, the enhancement of rates for the R (P) enantiomers, coupled with the reduction of the S (P) enantiomers, was sufficient to invert markedly the enantiomeric preference. The sequence of mutations to enlarge the size of the AChE active-centre gorge, resembling in part the more spacious gorge of BChE, did not show an ordered conversion into BChE reactivity as anticipated for a rigid template. Rather, the individual aromatic residues may mutually interact to confer a distinctive stereospecificity pattern towards organophosphates. PMID:12665427

  11. Co-Ln mixed-metal phosphonate grids and cages as molecular magnetic refrigerants.

    PubMed

    Zheng, Yan-Zhen; Evangelisti, Marco; Tuna, Floriana; Winpenny, Richard E P

    2012-01-18

    The synthesis, structures, and magnetic properties of six families of cobalt-lanthanide mixed-metal phosphonate complexes are reported in this Article. These six families can be divided into two structural types: grids, where the metal centers lie in a single plane, and cages. The grids include [4 × 3] {Co(8)Ln(4)}, [3 × 3] {Co(4)Ln(6)}, and [2 × 2] {Co(4)Ln(2)} families and a [4 × 4] {Co(8)Ln(8)} family where the central 2 × 2 square is rotated with respect to the external square. The cages include {Co(6)Ln(8)} and {Co(8)Ln(2)} families. Magnetic studies have been performed for these compounds, and for each family, the maximum magnetocaloric effect (MCE) has been observed for the Ln = Gd derivative, with a smaller MCE for the compounds containing magnetically anisotropic 4f-ions. The resulting entropy changes of the gadolinium derivatives are (for 3 K and 7 T) 11.8 J kg(-1) K(-1) for {Co(8)Gd(2)}; 20.0 J kg(-1) K(-1) for {Co(4)Gd(2)}; 21.1 J kg(-1) K(-1) for {Co(8)Gd(4)}; 21.4 J kg(-1) K(-1) for {Co(8)Gd(8)}; 23.6 J kg(-1) K(-1) for {Co(4)Gd(6)}; and 28.6 J kg(-1) K(-1) for {Co(6)Gd(8)}, from which we can see these values are proportional to the percentage of the gadolinium in the core. PMID:22171923

  12. Alternative pathways for phosphonate metabolism in thermophilic cyanobacteria from microbial mats

    PubMed Central

    Gomez-Garcia, Maria R; Davison, Michelle; Blain-Hartnung, Matthew; Grossman, Arthur R; Bhaya, Devaki

    2011-01-01

    Synechococcus sp. represents an ecologically diverse group of cyanobacteria found in numerous environments, including hot-spring microbial mats, where they are spatially distributed along thermal, light and oxygen gradients. These thermophiles engage in photosynthesis and aerobic respiration during the day, but switch to fermentative metabolism and nitrogen fixation at night. The genome of Synechococcus OS-B′, isolated from Octopus Spring (Yellowstone National Park) contains a phn gene cluster encoding a phosphonate (Phn) transporter and a C–P lyase. A closely related isolate, Synechococcus OS-A, lacks this cluster, but contains genes encoding putative phosphonatases (Phnases) that appear to be active only in the presence of the Phn substrate. Both isolates grow well on several different Phns as a sole phosphorus (P) source. Interestingly, Synechococcus OS-B′ can use the organic carbon backbones of Phns for heterotrophic growth in the dark, whereas in the light this strain releases organic carbon from Phn as ethane or methane (depending on the specific Phn available); Synechococcus OS-A has neither of these capabilities. These differences in metabolic strategies for assimilating the P and C of Phn by two closely related Synechococcus spp. are suggestive of niche-specific constraints in the evolution of nutrient assimilation pathways and syntrophic relationships among the microbial populations of the hot-spring mats. Thus, it is critical to evaluate levels of various P sources, including Phn, in thermally active habitats and the potential importance of these compounds in the biogeochemical cycling of P and C (some Phn compounds also contain N) in diverse terrestrial environments. PMID:20631809

  13. Actinide partitioning studies using dihexyl-N,N-diethycarbamolymehtyl phosphonate and dissolved zirconium calcine

    SciTech Connect

    Brewer, K.N.; Herbst, R.S.; Law, J.D.; Garn, T.G.; Tillotson, R.D.; Todd, T.A.

    1996-01-01

    A baseline flowsheet capable of partitioning the transuranic (TRU) elements from dissolved zirconium calcines has been developed. The goal of the TRU partitioning process is to remove the TRUs from solutions of dissolved zirconium calcines to below the 10 CFR 61.55 Class A waste limit of 10 nCi/g. Extraction, scrub, strip, and wash distribution coefficients for several elements, including the actinides, were measured in the laboratory by performing equal volume batch contacts. A solvent containing diheyl-N, N- diethylcarbamoylmethyl phosphonate (CMP), tributylphosphate (TBP), and a branched chain hydrocarbon as the diluent were used to develop this process. A non-radioactive zirconium pilot-plant calcine was spiked with the TRUs, U, Tc, or a radioactive isotope of zirconium to simulate the behavior of these elements in actual dissolved zirconium calcine feed. Distribution coefficient data obtained from laboratory testing were used to recommend: (1) solvent composition, (2) scrub solutions capable of selectively removing extracted zirconium while minimizing actinide recycle, (3) optimized strip solutions which quantitatively recover extracted actinides, and (4) feed adjustments necessary for flowsheet efficiency. Laboratory distribution coefficients were used in conjunction with the Generic TRUEX Model (GTM) to develop and recommend a flowsheet for testing in the 5.5-cm Centrifugal Contractor Mockup. GTM results indicate that the recommended flowsheet should remove the actinides from dissolved zirconium calcine feed to below the Class A waste limit of 10 nCi/g. Less than 0.01 wt% of the extracted zirconium will report to the high- activity waste (HAW) fraction using the 0.05 M H{sub 2}C{sub 2}O{sub 4} in 3.0 M HNO{sub 3} scrub, and greater than 99% of the extracted actinides are recovered with 0.001 M HEDPA.

  14. Alternative pathways for phosphonate metabolism in thermophilic cyanobacteria from microbial mats.

    PubMed

    Gomez-Garcia, Maria R; Davison, Michelle; Blain-Hartnung, Matthew; Grossman, Arthur R; Bhaya, Devaki

    2011-01-01

    Synechococcus sp. represents an ecologically diverse group of cyanobacteria found in numerous environments, including hot-spring microbial mats, where they are spatially distributed along thermal, light and oxygen gradients. These thermophiles engage in photosynthesis and aerobic respiration during the day, but switch to fermentative metabolism and nitrogen fixation at night. The genome of Synechococcus OS-B', isolated from Octopus Spring (Yellowstone National Park) contains a phn gene cluster encoding a phosphonate (Phn) transporter and a C-P lyase. A closely related isolate, Synechococcus OS-A, lacks this cluster, but contains genes encoding putative phosphonatases (Phnases) that appear to be active only in the presence of the Phn substrate. Both isolates grow well on several different Phns as a sole phosphorus (P) source. Interestingly, Synechococcus OS-B' can use the organic carbon backbones of Phns for heterotrophic growth in the dark, whereas in the light this strain releases organic carbon from Phn as ethane or methane (depending on the specific Phn available); Synechococcus OS-A has neither of these capabilities. These differences in metabolic strategies for assimilating the P and C of Phn by two closely related Synechococcus spp. are suggestive of niche-specific constraints in the evolution of nutrient assimilation pathways and syntrophic relationships among the microbial populations of the hot-spring mats. Thus, it is critical to evaluate levels of various P sources, including Phn, in thermally active habitats and the potential importance of these compounds in the biogeochemical cycling of P and C (some Phn compounds also contain N) in diverse terrestrial environments. PMID:20631809

  15. Cyclam Derivatives with a Bis(phosphinate) or a Phosphinato-Phosphonate Pendant Arm: Ligands for Fast and Efficient Copper(II) Complexation for Nuclear Medical Applications.

    PubMed

    David, Tomáš; Kubíček, Vojtěch; Gutten, Ondrej; Lubal, Přemysl; Kotek, Jan; Pietzsch, Hans-Jürgen; Rulíšek, Lubomír; Hermann, Petr

    2015-12-21

    Cyclam derivatives bearing one geminal bis(phosphinic acid), -CH2PO2HCH2PO2H2 (H2L(1)), or phosphinic-phosphonic acid, -CH2PO2HCH2PO3H2 (H3L(2)), pendant arm were synthesized and studied as potential copper(II) chelators for nuclear medical applications. The ligands showed good selectivity for copper(II) over zinc(II) and nickel(II) ions (log KCuL = 25.8 and 27.7 for H2L(1) and H3L(2), respectively). Kinetic study revealed an unusual three-step complex formation mechanism. The initial equilibrium step leads to out-of-cage complexes with Cu(2+) bound by the phosphorus-containing pendant arm. These species quickly rearrange to an in-cage complex with cyclam conformation II, which isomerizes to another in-cage complex with cyclam conformation I. The first in-cage complex is quantitatively formed in seconds (pH ≈5, 25 °C, Cu:L = 1:1, cM ≈ 1 mM). At pH >12, I isomers undergo nitrogen atom inversion, leading to III isomers; the structure of the III-[Cu(HL(2))] complex in the solid state was confirmed by X-ray diffraction analysis. In an alkaline solution, interconversion of the I and III isomers is mutual, leading to the same equilibrium isomeric mixture; such behavior has been observed here for the first time for copper(II) complexes of cyclam derivatives. Quantum-chemical calculations showed small energetic differences between the isomeric complexes of H3L(2) compared with analogous data for isomeric complexes of cyclam derivatives with one or two methylphosphonic acid pendant arm(s). Acid-assisted dissociation proved the kinetic inertness of the complexes. Preliminary radiolabeling of H2L(1) and H3L(2) with (64)Cu was fast and efficient, even at room temperature, giving specific activities of around 70 GBq of (64)Cu per 1 μmol of the ligand (pH 6.2, 10 min, ca. 90 equiv of the ligand). These specific activities were much higher than those of H3nota and H4dota complexes prepared under identical conditions. The rare combination of simple ligand synthesis, very

  16. Kirkwood-Buff analysis of aqueous N-methylacetamide and acetamide solutions modeled by the CHARMM additive and Drude polarizable force fields.

    PubMed

    Lin, Bin; Lopes, Pedro E M; Roux, Benoît; MacKerell, Alexander D

    2013-08-28

    Kirkwood-Buff analysis was performed on aqueous solutions of N-methylacetamide and acetamide using the Chemistry at HARvard Molecular Mechanics additive and Drude polarizable all-atom force fields. Comparison of a range of properties with experimental results, including Kirkwood-Buff integrals, excess coordination numbers, solution densities, partial molar values, molar enthalpy of mixing, showed both models to be well behaved at higher solute concentrations with the Drude model showing systematic improvement at lower solution concentrations. However, both models showed difficulties reproducing experimental activity derivatives and the excess Gibbs energy, with the Drude model performing slightly better. At the molecular level, the improved agreement of the Drude model at low solute concentrations is due to increased structure in the solute-solute and solute-solvent interactions. The present results indicate that the explicit inclusion of electronic polarization leads to improved modeling of dilute solutions even when those properties are not included as target data during force field optimization. PMID:24007020

  17. Glass transition dynamics and conductivity scaling in ionic deep eutectic solvents: The case of (acetamide + lithium nitrate/sodium thiocyanate) melts

    NASA Astrophysics Data System (ADS)

    Tripathy, Satya N.; Wojnarowska, Zaneta; Knapik, Justyna; Shirota, Hideaki; Biswas, Ranjit; Paluch, Marian

    2015-05-01

    A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10-1-106 Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transition temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai's coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors.

  18. Glass transition dynamics and conductivity scaling in ionic deep eutectic solvents: The case of (acetamide + lithium nitrate/sodium thiocyanate) melts

    SciTech Connect

    Tripathy, Satya N. Wojnarowska, Zaneta; Knapik, Justyna; Paluch, Marian; Shirota, Hideaki; Biswas, Ranjit

    2015-05-14

    A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10{sup −1}-10{sup 6} Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transition temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai’s coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors.

  19. A novel compound 2-(4-{2-[(phenylthio)acetyl]carbonohydrazonoyl}phenoxy)acetamide downregulates TSLP through blocking of caspase-1/NF-κB pathways.

    PubMed

    Moon, Phil-Dong; Han, Na-Ra; Ryu, Ka-Jung; Kang, Sang-Woo; Go, Ji-Hyun; Jang, Jae-Bum; Choi, Youngjin; Kim, Hyung-Min; Jeong, Hyun-Ja

    2016-09-01

    Thymic stromal lymphopoietin (TSLP) is regarded as the main factor responsible for the pathogenesis of allergic disorders such as atopic dermatitis, chronic obstructive pulmonary diseases, and allergic rhinitis. As part of our continuing search for novel anti-inflammatory compounds, 2-(4-{2-[(phenylthio)acetyl]carbonohydrazonoyl}phenoxy)acetamide (PA) was analyzed. In the present study, we examined how PA regulates the mRNA expression and production of TSLP in the human mast cell line, HMC-1 cells. Computer-aided docking simulation, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, caspase-1 assay, and Western blotting were used to investigate the effects of PA. PA decreased the mRNA expression and production of TSLP in HMC-1 cells. PA (1μM) inhibited the TSLP production up to 87.710±5.201%. PA also improved the activation and phosphorylation of nuclear factor-κB as well as the degradation and phosphorylation of IκBα. Caspase-1 activation was up-regulated in activated HMC-1 cells, whereas caspase-1 activation was down-regulated by PA. Finally, PA inhibited ear swelling response induced by phorbol myristate acetate in mice. These results indicate that PA would be effective to treat inflammatory and atopic disorders through the down-regulations of TSLP. PMID:27376852

  20. Glass transition dynamics and conductivity scaling in ionic deep eutectic solvents: The case of (acetamide + lithium nitrate/sodium thiocyanate) melts.

    PubMed

    Tripathy, Satya N; Wojnarowska, Zaneta; Knapik, Justyna; Shirota, Hideaki; Biswas, Ranjit; Paluch, Marian

    2015-05-14

    A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10(-1)-10(6) Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transition temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai's coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors. PMID:25978897

  1. Synthesis of conformationally locked L-deoxythreosyl phosphonate nucleosides built on a bicyclo[3.1.0]hexane template.

    PubMed

    Saneyoshi, Hisao; Deschamps, Jeffrey R; Marquez, Victor E

    2010-11-19

    Two conformationally locked versions of l-deoxythreosyl phosphonate nucleosides (2 and 3) were synthesized to investigate the preference of HIV reverse transcriptase for a conformation displaying either a fully diaxial or fully diequatorial disposition of substituents. Synthesis of the enantiomeric 4-(6-amino-9H-purin-9-yl)bicyclo[3.1.0]hexan-2-ol carbocyclic nucleoside precursors (diaxially disposed) proceeded straightforwardly from commercially available (1R,4S)-4-hydroxy-2-cyclopent-2-enyl-1-yl acetate employing a hydroxyl-directed Simmons-Smith cyclopropanation that culminated with a Mitsunobu coupling of the purine base. For the more complicated 1-(6-amino-9H-purin-9-yl)bicyclo[3.1.0]hexan-3-ol carbocyclic nucleoside precursors (diequatorially disposed), the obligatory linear approach required the syntheses of key 1-aminobicyclo[3.1.0.]hexan-3-yl benzoate precursors that were assembled via the amide variant of the Kulinkovich reaction involving the intramolecular cyclopropanation of a substituted δ-vinylamide. Completion of the purine ring was achieved by conventional approaches but with much improved yields through the use of a microwave reactor. The syntheses of the phosphonates and the corresponding diphosphates were achieved by conventional means. None of the diphosphates, which were supposed to act as nucleoside triphosphate mimics, could compete with dATP even when present in a 10-fold excess. PMID:20964394

  2. Novel alpha-zirconium phosphonates for the reinforcement of ductile thermoplastics

    NASA Astrophysics Data System (ADS)

    Furman, Benjamin R.

    2007-12-01

    Ductile thermoplastics are useful additives for providing fracture toughness to brittle thermosetting polymers; however, this toughening is usually accompanied by a significant decrease in elastic modulus. Therefore, alpha-zirconium phosphonates (ZrP) were developed and investigated as reinforcing nano-scale fillers that increase the yield strength and elastic modulus of a polyester thermoplastic without causing a reduction in its ductility. ZrP materials are synthetic layered compounds that are imbued with targeted organic surface functionalities and whose structural development can be carefully controlled in the laboratory. Ether-terminal alkyl ZrP materials were designed and synthesized, using a conventional ZrF62--mediated preparation, with the intent of developing strong dipole-dipole interactions between the layer surfaces and polyester macromolecules. Additionally, a general method for using lamellar lyotropic liquid crystals (LLC's) as supramolecular templates for alkyl ZrP was evaluated, whose products showed promising similarity to the conventionally prepared materials. The LLC-forming characteristics of several organophosphonate preparations were determined, showing improved mesophase stability with mixed amphiphiles and preparation with R4N + counterions. A mixed-surface octyl/methoxyundecyl ZrP was produced and combined with polycaprolactone (PCL) and polymethylmethacrylate (PMMA) in concentrations up to 50% (w/w). The mechanical properties of the ZrP/PCL nanocomposite were evaluated by tensile, flexural, and dynamic mechanical testing methods. Nanocomposites containing 5% (w/w) ZrP showed significant increases in tensile yield stress and elastic modulus without suffering any loss of ductility versus the unfilled polymer. Layer delamination from the ZrP tactoids was minimal and did not occur through an intercalative mechanism. Higher ZrP loadings resulted in the agglomeration of tactoids, leading to defect structures and loss of strength and ductility

  3. Synthesis and antiproliferative evaluation of novel 2-(4H-1,2,4-triazole-3-ylthio)acetamide derivatives as inducers of apoptosis in cancer cells.

    PubMed

    Kulabaş, Necla; Tatar, Esra; Bingöl Özakpınar, Özlem; Özsavcı, Derya; Pannecouque, Christophe; De Clercq, Erik; Küçükgüzel, İlkay

    2016-10-01

    In this study, a series of thiosemicarbazide derivatives 12-14, 1,2,4-triazol-3-thione derivatives 15-17 and compounds bearing 2-(4H-1,2,4-triazole-3-ylthio)acetamide structure 18-32 have been synthesized starting from phenolic compounds such as 2-naphthol, paracetamol and thymol. Structures and purity of the target compounds were confirmed by the use of their chromatographic and spectral data besides microanalysis. All of the synthesized new compounds 12-32 were evaluated for their anti-HIV activity. Among these compounds, three representatives 18, 19 and 25 were selected and evaluated by the National Cancer Institute (NCI) against the full panel of 60 human cancer cell lines derived from nine different cancer types. Antiproliferative effects of the selected compounds were demonstrated in human tumor cell lines K-562, A549 and PC-3. These compounds inhibited cell growth assessed by MTT assay. Compound 18, 19 and 25 exhibited anti-cancer activity with IC50 values of 5.96 μM (PC-3 cells), 7.90 μM (A549/ATCC cells) and 7.71 μM (K-562 cells), respectively. After the cell viability assay, caspase activation and Bcl-2 activity of the selected compounds were measured and the loss of mitochondrial membrane potential (MMP) was detected. Compounds 18, 19 and 25 showed a significant increase in caspase-3 activity in a dose-dependent manner. This was not observed for caspase-8 activity with compound 18 and 25, while compound 19 was significantly elevated only at the dose of 50 μM. In addition, all three compounds significantly decreased the mitochondrial membrane potential and expression of Bcl-2. PMID:27214512

  4. In situ direct photoproduction of ketenes from substituted coumarins isolated in solid argon: The case of N-(2-oxo-2 H-chromen-3-yl)acetamide

    NASA Astrophysics Data System (ADS)

    Kuş, N.; Breda, S.; Fausto, R.

    2009-04-01

    In this study, the infrared spectrum of N-(2-oxo-2 H-chromen-3-yl)acetamide (3-acetamidocoumarin; 3AC) isolated in solid argon, at 10 K, was obtained and assigned. In consonance with the relative energies of the three conformers predicted theoretically, only the most stable form was observed experimentally. This conformer is stabilized by two intramolecular hydrogen bonds and is similar to the structural unit of 3AC found in crystalline phase. Upon in situ UV ( λ > 215 nm) irradiation of the matrix-isolated compound, the characteristic IR intense band due to the antisymmetric stretching vibration of the ketene ( sbnd C dbnd C dbnd O) group was observed, indicating occurrence of the ring-opening isomerization reaction to the open-ring ketene isomeric of 3AC. In consonance with the theoretical structural predictions for the most stable isomers of this photoproduct, the experimental data indicates that it is produced in the E arrangement of the (O dbnd )C sbnd C dbnd C sbnd C( dbnd C dbnd O) fragment. There were also experimental indications pointing to occurrence of a second photoreaction channel, corresponding to decarbonylation. On the other hand, contrarily to what is generally observed for α-pyrones derivatives, including unsubstituted coumarin, no photochemical production of Dewar isomer of 3AC was observed. This last result, follows the trend observed for 2-pyrone-3-carboxylate, and seems to be a quite general rule for matrix-isolated α-pyrones bearing relatively volumous substituents at the position 3, as a consequence of the unfavorable relaxation of the matrix around the guest molecule that would be required to accommodate the Dewar isomers of these compounds, whose structure deviates strongly from planarity, thus mismatching the primarily occupied matrix sites.

  5. Hit to lead optimization of a series of N-[4-(1,3-benzothiazol-2-yl)phenyl]acetamides as monoacylglycerol lipase inhibitors with potential anticancer activity.

    PubMed

    Afzal, Obaid; Akhtar, Md Sayeed; Kumar, Suresh; Ali, Md Rahmat; Jaggi, Manu; Bawa, Sandhya

    2016-10-01

    A total of thirty five new N-[4-(1,3-benzothiazol-2-yl)phenyl]acetamide derivatives were synthesized and structures of all the compounds were confirmed on the basis of elemental analysis and collective use of IR, (1)H NMR, (13)C NMR and mass spectral data. Compounds were tested for their ability to inhibit human monoacylglycerol lipase (hMAGL) enzyme. Eight compounds 4, 19-21, 24-26, and 34 reduced the hMAGL activity less than 50% at 100 nM concentrations. The halogen substituted aniline derivatives 20, 21 and 24-26 were found to be most active among all the synthesized compounds having IC50 value in the range of 6.5-9 nM. Twenty five compounds were selected by NCI, USA for one dose anticancer screening. Compound 21 (NSC: 780167) and 24 (NSC: 780168) fulfilled prearranged doorstep growth inhibition criteria and further selected for NCI full panel five dose assay at 10-fold dilutions of five different concentrations (0.01, 0.1, 1, 10 and 100 μM). Both the compounds 21 and 24 were found to be most active against MCF7 and MDA-MB-468 breast cancer cell lines. The GI50 value of 32.5 nM (MCF7) and 23.8 nM (MDA-MB-468) was observed for compound 21. Compound 24 showed GI50 values of 37.1 nM against MCF7 breast cancer cell line and 25.1 nM against MDA-MB-468 breast cancer cell line. PMID:27267002

  6. Discovery of 2-((3-cyanopyridin-2-yl)thio)acetamides as human lactate dehydrogenase A inhibitors to reduce the growth of MG-63 osteosarcoma cells: Virtual screening and biological validation.

    PubMed

    Cui, Wei; Lv, Wei; Qu, Ying; Ma, Rui; Wang, Yi-Wei; Xu, Yong-Jun; Wu, Di; Chen, Xuanhuang

    2016-08-15

    Lactate dehydrogenase A (LDHA) has emerged as an attractive target in the oncology field. In this paper, we present the identification of 2-((3-cyanopyridin-2-yl)thio)acetamide-containing compounds as LDHA inhibitors. The in vitro enzymatic assay suggested that inhibitor 9 had good inhibitory potency against LDHA with IC50 value as 1.24μM. Cytotoxicity assay showed that inhibitor 9 strongly inhibited the proliferation of cancer cell MG-63 (EC50=0.98μM). These findings indicated that inhibitor 9 could be employed as a lead for developing more potent LDHA inhibitor with anti-proliferative potency. PMID:27406795

  7. Regioselective Copper-Catalyzed Dicarbonylation of Imidazo[1,2-a]pyridines with N,N-Disubstituted Acetamide or Acetone: An Approach to 1,2-Diketones Using Molecular Oxygen.

    PubMed

    Wang, Changcheng; Lei, Sai; Cao, Hua; Qiu, Shuxian; Liu, Jingyun; Deng, Hao; Yan, Caijuan

    2015-12-18

    A novel copper-catalyzed regioselective double carbonylation of imidazo[1,2-a]pyridines with N,N-disubstituted acetamide or acetone using molecular oxygen has been described. It has provided a new approach to synthesize 1,2-carbonyl imidazo[1,2-a]pyridines, which are important substrates and intermediates in preparation of fine chemicals. The product shares a skeleton similar to that of Zolpidem, one of the most prescribed drugs in the world. (18)O-labeling experiments unambiguously established that the oxygen source of products originated from O2 rather than H2O. PMID:26595127

  8. Sources of aminomethylphosphonic acid (AMPA) in urban and rural catchments in Ontario, Canada: Glyphosate or phosphonates in wastewater?

    PubMed

    Struger, J; Van Stempvoort, D R; Brown, S J

    2015-09-01

    Correlation analysis suggests that occurrences of AMPA in streams of southern Ontario are linked mainly to glyphosate in both urban and rural settings, rather than to wastewater sources, as some previous studies have suggested. For this analysis the artificial sweetener acesulfame was analyzed as a wastewater indicator in surface water samples collected from urban and rural settings in southern Ontario, Canada. This interpretation is supported by the concurrence of seasonal fluctuations of glyphosate and AMPA concentrations. Herbicide applications in larger urban centres and along major transportation corridors appear to be important sources of glyphosate and AMPA in surface water, in addition to uses of this herbicide in rural and mixed use areas. Fluctuations in concentrations of acesulfame and glyphosate residues were found to be related to hydrologic events. PMID:26187493

  9. Use of acyl phosphonates for the synthesis of inulin esters and their use as emulsion stabilizing agents.

    PubMed

    Rogge, Tina M; Stevens, Christian V; Colpaert, Anton; Levecke, Bart; Booten, Karl

    2007-02-01

    Inulin, the polydisperse polyfructose, extracted from chicory, was modified via esterification with acyl phosphonates. The grafting of an acyl chain onto the inulin backbone under different conditions led to a highly efficient synthesis of a series of inulin esters, with interesting tensioactive properties. The derivatives were evaluated in oil-in-water (O/W) emulsions with isoparaffinic oil, Isopar M. Therefore, a 2% (w/v) aqueous solution of inulin-based surfactant was used in 50/50 O/W emulsions, in nonelectrolyte, and in electrolyte media, using 1 M MgSO4. Longer acyl chains, e.g., dodecanoyl (C12), hexadecanoyl (C16), and octadecanoyl (C18), with degrees of substitution lower than 0.5, gave rise to the highest emulsion stabilities against coalescence. PMID:17291072

  10. Sub-parts-per-billion level detection of dimethyl methyl phosphonate (DMMP) by quantum cascade laser photoacoustic spectroscopy.

    PubMed

    Mukherjee, Anadi; Dunayevskiy, Ilya; Prasanna, Manu; Go, Rowel; Tsekoun, Alexei; Wang, Xiaojun; Fan, Jenyu; Patel, C Kumar N

    2008-04-01

    The need for the detection of chemical warfare agents (CWAs) is no longer confined to battlefield environments because of at least one confirmed terrorist attack, the Tokyo Subway [Emerg. Infect. Dis. 5, 513 (1999)] in 1995, and a suspected, i.e., a false-alarm of a CWA in the Russell Senate Office Building [Washington Post, 9 February 2006, p. B01]. Therefore, detection of CWAs with high sensitivity and low false-alarm rates is considered an important priority for ensuring public safety. We report a minimum detection level for a CWA simulant, dimethyl methyl phosphonate (DMMP), of <0.5 ppb (parts in 10(9)) by use of a widely tunable external grating cavity quantum cascade laser and photoacoustic spectroscopy. With interferents present in Santa Monica, California street air, we demonstrate a false-alarm rate of 1:10(6) at a detection threshold of 1.6 ppb. PMID:18382583

  11. New Selective Peptidyl Di(chlorophenyl) Phosphonate Esters for Visualizing and Blocking Neutrophil Proteinase 3 in Human Diseases*

    PubMed Central

    Guarino, Carla; Legowska, Monika; Epinette, Christophe; Kellenberger, Christine; Dallet-Choisy, Sandrine; Sieńczyk, Marcin; Gabant, Guillaume; Cadene, Martine; Zoidakis, Jérôme; Vlahou, Antonia; Wysocka, Magdalena; Marchand-Adam, Sylvain; Jenne, Dieter E.; Lesner, Adam; Gauthier, Francis; Korkmaz, Brice

    2014-01-01

    The function of neutrophil protease 3 (PR3) is poorly understood despite of its role in autoimmune vasculitides and its possible involvement in cell apoptosis. This makes it different from its structural homologue neutrophil elastase (HNE). Endogenous inhibitors of human neutrophil serine proteases preferentially inhibit HNE and to a lesser extent, PR3. We constructed a single-residue mutant PR3 (I217R) to investigate the S4 subsite preferences of PR3 and HNE and used the best peptide substrate sequences to develop selective phosphonate inhibitors with the structure Ac-peptidylP(O-C6H4-4-Cl)2. The combination of a prolyl residue at P4 and an aspartyl residue at P2 was totally selective for PR3. We then synthesized N-terminally biotinylated peptidyl phosphonates to identify the PR3 in complex biological samples. These inhibitors resisted proteolytic degradation and rapidly inactivated PR3 in biological fluids such as inflammatory lung secretions and the urine of patients with bladder cancer. One of these inhibitors revealed intracellular PR3 in permeabilized neutrophils and on the surface of activated cells. They hardly inhibited PR3 bound to the surface of stimulated neutrophils despite their low molecular mass, suggesting that the conformation and reactivity of membrane-bound PR3 is altered. This finding is relevant for autoantibody binding and the subsequent activation of neutrophils in granulomatosis with polyangiitis (formerly Wegener disease). These are the first inhibitors that can be used as probes to monitor, detect, and control PR3 activity in a variety of inflammatory diseases. PMID:25288799

  12. Reversible Phase Variation in the phnE Gene, Which Is Required for Phosphonate Metabolism in Escherichia coli K-12

    PubMed Central

    Iqbal, Samina; Parker, George; Davidson, Helen; Moslehi-Rahmani, Elham; Robson, Robert L.

    2004-01-01

    It is known that Escherichia coli K-12 is cryptic (Phn−) for utilization of methyl phosphonate (MePn) and that Phn+ variants can be selected for growth on MePn as the sole P source. Variants arise from deletion via a possible slip strand mechanism of one of three direct 8-bp repeat sequences in phnE, which restores function to a component of a putative ABC type transporter. Here we show that Phn+ variants are present at the surprisingly high frequency of >10−2 in K-12 strains. Amplified-fragment length polymorphism analysis was used to monitor instability in phnE in various strains growing under different conditions. This revealed that, once selection for growth on MePn is removed, Phn+ revertants reappear and accumulate at high levels through reinsertion of the 8-bp repeat element sequence. It appears that, in K-12, phnE contains a high-frequency reversible gene switch, producing phase variation which either allows (“on” form) or blocks (“off” form) MePn utilization. The switch can also block usage of other metabolizable alkyl phosphonates, including the naturally occurring 2-aminoethylphosphonate. All K-12 strains, obtained from collections, appear in the “off” form even when bearing mutations in mutS, mutD, or dnaQ which are known to enhance slip strand events between repetitive sequences. The ability to inactivate the phnE gene appears to be unique to K-12 strains since the B strain is naturally Phn+ and lacks the inactivating 8-bp insertion in phnE, as do important pathogenic strains for which genome sequences are known and also strains isolated recently from environmental sources. PMID:15342581

  13. Crystal structures of 2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]-N-(3-nitro-phen-yl)acetamide monohydrate and N-(2-chloro-phen-yl)-2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]acetamide.

    PubMed

    Subasri, S; Timiri, Ajay Kumar; Barji, Nayan Sinha; Jayaprakash, Venkatesan; Vijayan, Viswanathan; Velmurugan, Devadasan

    2016-08-01

    The title compounds, C12H12N6O3S·H2O, (I), and C12H12ClN5OS, (II), are 2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]acetamides. Compound (I) crystallized as a monohydrate. In both compounds, the mol-ecules have a folded conformation, with the pyrimidine ring being inclined to the benzene ring by 56.18 (6)° in (I) and by 67.84 (6)° in (II). In both mol-ecules, there is an intra-molecular N-H⋯N hydrogen bond stabilizing the folded conformation. In (I), there is also a C-H⋯O intra-molecular short contact, and in (II) an intra-molecular N-H⋯Cl hydrogen bond is present. In the crystal of (I), mol-ecules are linked by a series of N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, forming undulating sheets parallel to the (100). The sheets are linked via an N-H⋯Owater hydrogen bond, forming a three-dimensional network. In the crystal of (II), mol-ecules are linked by a series of N-H⋯O, N-H⋯N and C-H⋯O hydrogen bonds, forming slabs parallel to (001). PMID:27536406

  14. Crystal structures of 2-[(4,6-di­amino­pyrimidin-2-yl)sulfan­yl]-N-(3-nitro­phen­yl)acetamide monohydrate and N-(2-chloro­phen­yl)-2-[(4,6-di­amino­pyrimidin-2-yl)sulfan­yl]acetamide

    PubMed Central

    Subasri, S.; Timiri, Ajay Kumar; Barji, Nayan Sinha; Jayaprakash, Venkatesan; Vijayan, Viswanathan; Velmurugan, Devadasan

    2016-01-01

    The title compounds, C12H12N6O3S·H2O, (I), and C12H12ClN5OS, (II), are 2-[(4,6-di­amino­pyrimidin-2-yl)sulfan­yl]acetamides. Compound (I) crystallized as a monohydrate. In both compounds, the mol­ecules have a folded conformation, with the pyrimidine ring being inclined to the benzene ring by 56.18 (6)° in (I) and by 67.84 (6)° in (II). In both mol­ecules, there is an intra­molecular N—H⋯N hydrogen bond stabilizing the folded conformation. In (I), there is also a C—H⋯O intra­molecular short contact, and in (II) an intra­molecular N—H⋯Cl hydrogen bond is present. In the crystal of (I), mol­ecules are linked by a series of N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, forming undulating sheets parallel to the (100). The sheets are linked via an N—H⋯Owater hydrogen bond, forming a three-dimensional network. In the crystal of (II), mol­ecules are linked by a series of N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds, forming slabs parallel to (001). PMID:27536406

  15. Enhancement of the Luminance Efficiency in Organic Light-Emitting Devices with p-Substituted Phenylphosphonic-Acid Self-Assembled Monolayers.

    PubMed

    Kim, Min Sung; Jeon, Young Pyo; Kim, Youngwoo; Noh, Jaegeun; Kim, Tae Whan

    2015-07-01

    Organic light-emitting devices (OLEDs) containing self-assembled monolayers (SAMs) prepared by using p-substituted phenylphosponic acids on indium-tin-oxide electrodes were fabricated and examined to understand the substituent effect of the SAMs on the device performance. OLEDs modified by using (4-methoxyphenyl)phosphonic acid (MOPPA) SAMs or (4-chlorophenyl)phosphonic acid (CPPA) SAMs, both with electron withdrawing groups, had enhanced hole injection, reduced operating voltage, and remarkably increased current density and luminance efficiency compared with those without SAMs. The luminance efficiency which was the ratio of luminous flux to power for OLEDs containing CPPA SAMs and that for the OLEDs containing MOPPA SAMs were enhanced 2.2 and 1.9 times, respectively, in comparison with that of OLEDs without SAMs. CPPA SAMs significantly reduced the operating voltage of OLED by 24.8% compared with OLEDs without SAMs. PMID:26373078

  16. Generation and exploitation of acyclic azomethine imines in chiral Brønsted acid catalysis

    NASA Astrophysics Data System (ADS)

    Hashimoto, Takuya; Kimura, Hidenori; Kawamata, Yu; Maruoka, Keiji

    2011-08-01

    Successful implementation of a catalytic asymmetric synthesis strategy to produce enantiomerically enriched compounds requires the adoption of suitable prochiral substrates. The combination of an azomethine imine electrophile with various nucleophiles could give straightforward access to a number of synthetically useful chiral hydrazines, but is used rarely. Here we report the exploitation of acyclic azomethine imines as a new type of prochiral electrophile. They can be generated in situ by the condensation of N‧-benzylbenzoylhydrazide with a variety of aldehydes in the presence of a catalytic amount of an axially chiral dicarboxylic acid. By trapping these electrophiles with alkyl diazoacetate or (diazomethyl)phosphonate nucleophiles, we produced a diverse array of chiral α-diazo-β-hydrazino esters and phosphonates with excellent enantioselectivities.

  17. Low-frequency collective dynamics in deep eutectic solvents of acetamide and electrolytes: A femtosecond Raman-induced Kerr effect spectroscopic study

    NASA Astrophysics Data System (ADS)

    Biswas, Ranjit; Das, Anuradha; Shirota, Hideaki

    2014-10-01

    In this study, we have investigated the ion concentration dependent collective dynamics in two series of deep eutectic solvent (DES) systems by femtosecond Raman-induced Kerr effect spectroscopy, as well as some physical properties, e.g., shear viscosity (η), density (ρ), and surface tension (γ). The DES systems studied here are [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] and [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] with f = 0, 0.2, 0.4, 0.6, 0.8, and 1.0. γ of these DES systems shows near insensitivity to f, while ρ shows a moderate dependence on f. Interestingly, η exhibits a strong dependence on f. In the low-frequency Kerr spectra, obtained via the Fourier transform of the collected Kerr transients, a characteristic band at ˜70 cm-1 is clear in [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] DES especially at the larger f. The band is attributed to the intermolecular hydrogen bond of acetamide. Because of less depolarized Raman activities of intermolecular/interionic vibrational motions, which are mostly translational (collision-induced or interaction-induced) motions, of spherical ions, the intermolecular hydrogen-bonding band is clearly observed. In contrast, the intermolecular hydrogen-bonding band is buried in the other intermolecular/interionic vibrational motions, which includes translational and reorientational (librational) motions and their cross-terms, in [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] system. The first moment (M1) of the intermolecular/interionic vibrational band in these DES systems is much higher than that in typical neutral molecular liquids and shows a weak but contrasting dependence on the bulk parameter sqrt {γ /ρ }. The time constants for picosecond overdamped Kerr transients in both the DES systems, which are obtained on the basis of the analysis fitted by a triexponential function, are rather insensitive to f for both the DES systems, but all the three time constants (fast: ˜1-3 ps; intermediate: ˜7-20 ps; and

  18. cycloSal-PMEA and cycloAmb-PMEA: potentially new phosphonate prodrugs based on the cycloSal-pronucleotide approach.

    PubMed

    Meier, Chris; Görbig, Ulf; Müller, Christian; Balzarini, Jan

    2005-12-15

    Two new classes of lipophilic prodrugs of the antiviral active phosphonate 9-[2-phosphonomethoxyethyl]adenine (PMEA 1) have been prepared and were studied with regard to their hydrolysis properties and biological activity. A first series of compounds was prepared on the basis of the cycloSal nucleotide approach. Because of the surprisingly low hydrolysis stability of these cycloSal-PMEA derivatives, more stable derivatives have to be developed. Instead of using salicyl alcohol, in cycloAmb-PMEA derivatives 2-aminobenzyl alcohols were attached to PMEA 1. The latter compounds showed a considerably higher stability compared to the cycloSal counterparts. Stability studies revealed that all lipophilic prodrugs delivered PMEA selectively by chemical means. All compounds proved to be noninhibiting to acetyl- and butyrylcholinesterase, and some of the phosphonate diesters were found to be more active against HIV compared to the parent PMEA. PMID:16335932

  19. Role of Acid Functionality and Placement on Morphological Evolution and Strengthening of Acid Copolymers

    NASA Astrophysics Data System (ADS)

    Middleton, Luri Robert; Schwartz, Eric; Winey, Karen

    Functional polymers with specific interactions produce hierarchical morphologies that directly impact mechanical properties. We recently reported that the formation of acid-rich layered morphologies in precise poly(ethylene-co-acrylic acid) copolymers improves tensile strength. We now explore the generality of this phenomenon through variations in pendant acid chemistries, acid content and precision in placement of acid groups in polyethylene-based copolymers. In situ X-ray scattering measurements during tensile deformation reveal that the precision in acid group placement is critical to forming well-defined layered morphologies. This phenomenon was observed in both semi-crystalline and amorphous precise acid copolymers with varied acid chemistries (acrylic, geminal acrylic and phosphonic acids). Compositionally identical polymers but with pseudo random acid placement do not form layered morphologies. Acid chemistry and acid content influence morphological evolution predominately though modification of the copolymer Tg and crystallinity. Our results indicate that hierarchical layered structures, commensurate with improved mechanical properties, form in the presence of uniformity in chemical structure and sufficient chain mobility to strongly align during deformation.

  20. Crystal structure of the complex of carboxypeptidase A with a strongly bound phosphonate in a new crystalline form: Comparison with structures of other complexes

    SciTech Connect

    Kim, Hidong; Lipscomb, W.N. )

    1990-06-12

    O-(((1R)-((N-(Phenylmethoxycarbonyl)-L-alanyl)amino)ethyl)hydroxyphosphinyl)-L-3-phenyllacetate (ZZA{sup P}(O)F), an analogue of (benzyloxycarbonyl)-Ala-Ala-Phe or (benzyloxycarbonyl)-Ala-Ala-phenyllactate, binds to carboxypeptidase A with great affinity. Similar phosphonates have been shown to be transition-state analogues of the CPA-catalyzed hydrolysis. In the present study, the structure of the complex of phosphonate with carboxypeptidase A has been determined by X-ray crystallography to a resolution of 2.0 {angstrom}. The structure of the complex was solved by molecular replacement. Refinement of the structure against 20,776 unique reflections between 10.0 and 2.0 {angstrom} yields a crystallographic residual of 0.193, including 140 water molecules. The two phosphinyl oxygens of the inhibitor bind to the active-site zinc at 2.2 {angstrom} on the electrophilic (Arg-127) side and 3.1 {angstrom} on the nucleophilic (Glu-270) side. Various features of the binding mode of this phosphonate inhibitor are consistent with the hypothesis that carboxypeptidase A catalyzed hydrolysis proceeds through a general-base mechanism in which the carbonyl carbon of the substrate is attached by Zn-hydroxyl (or Zn-water). This complex structure is compared with previous structures of carboxypeptidase A, including the complexes with the potato inhibitor, a hydrated keto methylene substrate analogue, and a phosphonamidate inhibitor. Comparisons are also made with the complexes of thermolysin with some phosphonamidate inhibitors.

  1. Visible-light-assisted photoelectrochemical water oxidation by thin films of a phosphonate-functionalized perylene diimide plus CoOx cocatalyst.

    PubMed

    Kirner, Joel T; Stracke, Jordan J; Gregg, Brian A; Finke, Richard G

    2014-08-27

    A novel perylene diimide dye functionalized with phosphonate groups, N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide (PMPDI), is synthesized and characterized. Thin films of PMPDI spin-coated onto indium tin oxide (ITO) substrates are further characterized, augmented by photoelectrochemically depositing a CoOx catalyst, and then investigated as photoanodes for water oxidation. These ITO/PMPDI/CoOx electrodes show visible-light-assisted water oxidation with photocurrents in excess of 150 μA/cm(2) at 1.0 V applied bias vs. Ag/AgCl. Water oxidation is confirmed by the direct detection of O2, with a faradaic efficiency of 80 ± 15% measured under 900 mV applied bias vs. Ag/AgCl. Analogous photoanodes prepared with another PDI derivative with alkyl groups in place of PMPDI's phosphonate groups do not function, providing evidence that PMPDI's phosphonate groups may be important for efficient coupling between the inorganic CoOx catalyst and the organic dye. Our ITO/PMPDI/CoOx anodes achieve internal quantum efficiencies for water oxidation ∼1%, and for hydroquinone oxidation of up to ∼6%. The novelty of our system is that, to the best of our knowledge, it is the first device to achieve photoelectrochemically driven water oxidation by a single-layer molecular organic semiconductor thin film coupled to a water-oxidation catalyst. PMID:24654796

  2. Low-frequency collective dynamics in deep eutectic solvents of acetamide and electrolytes: a femtosecond Raman-induced Kerr effect spectroscopic study.

    PubMed

    Biswas, Ranjit; Das, Anuradha; Shirota, Hideaki

    2014-10-01

    In this study, we have investigated the ion concentration dependent collective dynamics in two series of deep eutectic solvent (DES) systems by femtosecond Raman-induced Kerr effect spectroscopy, as well as some physical properties, e.g., shear viscosity (η), density (ρ), and surface tension (γ). The DES systems studied here are [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] and [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] with f = 0, 0.2, 0.4, 0.6, 0.8, and 1.0. γ of these DES systems shows near insensitivity to f, while ρ shows a moderate dependence on f. Interestingly, η exhibits a strong dependence on f. In the low-frequency Kerr spectra, obtained via the Fourier transform of the collected Kerr transients, a characteristic band at ∼70 cm(-1) is clear in [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] DES especially at the larger f. The band is attributed to the intermolecular hydrogen bond of acetamide. Because of less depolarized Raman activities of intermolecular/interionic vibrational motions, which are mostly translational (collision-induced or interaction-induced) motions, of spherical ions, the intermolecular hydrogen-bonding band is clearly observed. In contrast, the intermolecular hydrogen-bonding band is buried in the other intermolecular/interionic vibrational motions, which includes translational and reorientational (librational) motions and their cross-terms, in [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] system. The first moment (M1) of the intermolecular/interionic vibrational band in these DES systems is much higher than that in typical neutral molecular liquids and shows a weak but contrasting dependence on the bulk parameter √γ/ρ. The time constants for picosecond overdamped Kerr transients in both the DES systems, which are obtained on the basis of the analysis fitted by a triexponential function, are rather insensitive to f for both the DES systems, but all the three time constants (fast: ∼1-3 ps; intermediate:

  3. Isoprenoid biosynthesis as a target for antibacterial and antiparasitic drugs: phosphonohydroxamic acids as inhibitors of deoxyxylulose phosphate reducto-isomerase

    PubMed Central

    2004-01-01

    Isoprenoid biosynthesis via the methylerythritol phosphate pathway is a target against pathogenic bacteria and the malaria parasite Plasmodium falciparum. 4-(Hydroxyamino)-4-oxobutylphosphonic acid and 4-[hydroxy(methyl)amino]-4-oxobutyl phosphonic acid, two novel inhibitors of DXR (1-deoxy-D-xylulose 5-phosphate reducto-isomerase), the second enzyme of the pathway, have been synthesized and compared with fosmidomycin, the best known inhibitor of this enzyme. The latter phosphonohydroxamic acid showed a high inhibitory activity towards DXR, much like fosmidomycin, as well as significant antibacterial activity against Escherichia coli in tests on Petri dishes. PMID:15473867

  4. Design and synthesis of phosphonoacetic acid (PPA) ester and amide bioisosters of ribofuranosylnucleoside diphosphates as potential ribonucleotide reductase inhibitors and evaluation of their enzyme inhibitory, cytostatic and antiviral activity.

    PubMed

    Manfredini, Stefano; Solaroli, Nicola; Angusti, Angela; Nalin, Federico; Durini, Elisa; Vertuani, Silvia; Pricl, Sabrina; Ferrone, Marco; Spadari, Silvio; Focher, Federico; Verri, Annalisa; De Clercq, Erik; Balzarini, Jan

    2003-07-01

    Continuing our investigations on inhibitors of ribonucleotide reductase (RNR), the crucial enzyme that catalyses the reduction of ribonucleotides to deoxyribonucleotides, we have now prepared and evaluated 5'-phosphonoacetic acid, amide and ester analogues of adenosine, uridine and cytidine with the aim to verify both substrate specificity and contribution to biological activity of diphosphate mimic moieties. A molecular modelling study has been conducted on the RNR R1 subunit, in order to verify the possible interaction of the proposed bioisosteric moieties. The study compounds were finally tested on the recombinant murine RNR showing a degree of inhibition that ranged from 350 microM for the UDP analogue 5'-deoxy-5'-N-(phosphon-acetyl)uridine sodium salt (amide) to 600 microM for the CDP analogue 5'-O-[(diethyl-phosphon)acetyl]cytidine (ester). None of the tested compounds displayed noteworthy cytostatic activity at 100-500 microM concentrations, whereas ADP analogue 5'-N-[(diethyl-phosphon) acetyl]adenosine (amide) and 5'-deoxy-5'-N-(phosphon-acetyl)adenosine sodium salt (amide) showed a moderate inhibitory activity (EC50: 48 microM) against HSV-2 and a modest inhibitory activity (EC50: 110 microM) against HIV-1, respectively. PMID:14582847

  5. SYNTHESIS AND BIOLOGICAL EVALUATION OF N-(SUBSTITUTED PHENYL)-2-(5H-[1,2,4]TRIAZINO[5,6-b]INDOL-3-YLSULFANYL)ACETAMIDES AS ANTIMICROBIAL, ANTIDEPRESSANT AND ANTICONVULSANT AGENTS.

    PubMed

    Shruthi, N; Poojary, Boja; Kumar, Vasantha; Prathibha, A; Hussain, Mumtaz Mohammed; Revanasiddappa, B C; Joshi, Himanshu

    2015-01-01

    A new series of N-Aryl-2-(5H-[1,2,4]triazino[5,6-b]indol-3-ylsulfanyl)acetamides were synthesized by condensation of tricyclic compound 2,5-dihydro-3H-[1,2,4]triazino[5,6-b]indole-3-thione with chloro N-phenylacetamides. The tricyclic compound was obtained by condensation of Isatin with thiosemicarbazide. Chloro N-phenylacetamides were obtained from different substituted anilines. Their structures were characterized by IR, 1H NMR, LC-MS and elemental analyses. Newly synthesized compounds were screened for antimicrobial, antidepressant and anticonvulsant activities. Preliminary results indicated that most of the compounds showed lesser MIC value than the standard drug used when tested for antimicrobial activity. Some of the compounds were endowed with very good antidepressant and anticonvulsant activity. PMID:26165132

  6. Structural analysis of a phosphonate hydroxylase with an access tunnel at the back of the active site.

    PubMed

    Li, Changqing; Junaid, Muhammad; Almuqri, Eman Abdullah; Hao, Shiguang; Zhang, Houjin

    2016-05-01

    FrbJ is a member of the Fe(2+)/α-ketoglutarate-dependent dioxygenase family which hydroxylates the natural product FR-900098 of Streptomyces rubellomurinus, yielding the phosphonate antibiotic FR-33289. Here, the crystal structure of FrbJ, which shows structural homology to taurine dioxygenase (TauD), a key member of the same family, is reported. Unlike other members of the family, FrbJ has an unusual lid structure which consists of two β-strands with a long loop between them. To investigate the role of this lid motif, a molecular-dynamics simulation was performed with the FrbJ structure. The molecular-dynamics simulation analysis implies that the lid-loop region is highly flexible, which is consistent with the fact that FrbJ has a relatively broad spectrum of substrates with different lengths. Interestingly, an access tunnel is found at the back of the active site which connects the putative binding site of α-ketoglutarate to the solvent outside. PMID:27139827

  7. New N-Acetyltransferase Fold in the Structure and Mechanism of the Phosphonate Biosynthetic Enzyme FrbF

    SciTech Connect

    Bae, Brian; Cobb, Ryan E.; DeSieno, Matthew A.; Zhao, Huimin; Nair, Satish K.

    2015-10-15

    The enzyme FrbF from Streptomyces rubellomurinus has attracted significant attention due to its role in the biosynthesis of the antimalarial phosphonate FR-900098. The enzyme catalyzes acetyl transfer onto the hydroxamate of the FR-900098 precursors cytidine 5'-monophosphate-3-aminopropylphosphonate and cytidine 5'-monophosphate-N-hydroxy-3-aminopropylphosphonate. Despite the established function as a bona fide N-acetyltransferase, FrbF shows no sequence similarity to any member of the GCN5-like N-acetyltransferase (GNAT) superfamily. Here, we present the 2.0 {angstrom} resolution crystal structure of FrbF in complex with acetyl-CoA, which demonstrates a unique architecture that is distinct from those of canonical GNAT-like acetyltransferases. We also utilized the co-crystal structure to guide structure-function studies that identified the roles of putative active site residues in the acetyltransferase mechanism. The combined biochemical and structural analyses of FrbF provide insights into this previously uncharacterized family of N-acetyltransferases and also provide a molecular framework toward the production of novel N-acyl derivatives of FR-900098.

  8. Detection of a nerve agent simulant using single-walled carbon nanotube networks: dimethyl-methyl-phosphonate.

    PubMed

    Kim, Yeonju; Lee, Seunghyun; Choi, Hyang Hee; Noh, Jin-Seo; Lee, Wooyoung

    2010-12-10

    Single-walled carbon nanotube (SWNT) networks were used to detect hazardous dimethyl-methyl-phosphonate (DMMP) gas in real time, employing two different metals as electrodes. Random networks of SWNTs were simply obtained by drop-casting a SWNT-containing solution onto a surface-oxidized Si substrate. Although the electrical responses to DMMP at room temperature were reversible for both metals, the Pd-contacting SWNT network sensors exhibited a higher response and a shorter response time than those of the Au-contacting SWNT network sensors at the same DMMP concentration, due to the stronger interactions between the SWNTs and Pd surface atoms. In Pd-contacting SWNT network sensors, the response increased linearly with increasing DMMP concentration and reproducible response curves were obtained for DMMP levels as low as 1 ppm. These results indicate that SWNT networks in contact with Pd electrodes can function as good DMMP sensors at room temperature with scalable and fast response and excellent recovery. PMID:21079292

  9. Synthesis of a C-phosphonate mimic of maltose-1-phosphate and inhibition studies on Mycobacterium tuberculosis GlgE

    PubMed Central

    Veleti, Sri Kumar; Lindenberger, Jared J.; Ronning, Donald R.; Sucheck, Steven J.

    2014-01-01

    The emergence of extensively drug-resistant tuberculosis (XDR-TB) necessitates the need to identify new anti-tuberculosis drug targets as well as to better understand essential biosynthetic pathways. GlgE is a Mycobacterium tuberculosis (Mtb) encoded maltosyltransferase involved in α-glucan biosynthesis. Deletion of GlgE in Mtb results in the accumulation of M1P within cells leading to rapid death of the organism. To inhibit GlgE a maltose-C-phosphonate (MCP) 13 was designed to act as an isosteric non-hydrolysable mimic of M1P. MCP 13, the only known inhibitor of Mtb GlgE, was successfully synthesized using a Wittig olefination as a key step in transforming maltose to the desired product. MCP 13 inhibited Mtb GlgE with an IC50 = 230 ± 24 μM determined using a coupled enzyme assay which measures orthophosphate release. The requirement of M1P for the assay necessitated the development of an expedited synthetic route to M1P from an intermediate used in the MCP 13 synthesis. In conclusion, we designed a substrate analogue of M1P that is the first to exhibit Mtb GlgE inhibition. PMID:24461562

  10. Synthesis of magnetron sputtered WO₃ nanoparticles-degradation of 2-chloroethyl ethyl sulfide and dimethyl methyl phosphonate.

    PubMed

    Verma, Monu; Chandra, Ramesh; Gupta, Vinod Kumar

    2015-09-01

    In the present study, tungsten oxide nanoparticles were synthesized using DC magnetron sputtering and investigated their potential for decontamination of 2-chloroethyl ethyl sulfide (CEES) and dimethyl methyl phosphonate (DMMP). The tungsten oxide nanoparticles were characterized by Powder XRD, FE-SEM, EDS, TEM, TGA, N2-BET and FT-IR techniques. The XRD patterns of as-deposited and post annealed tungsten oxide nanoparticles reveal that the crystallite size of detected monoclinic phase WO3 nanoparticle was increased with increasing annealing temperatures. The phase and increase in particles size of WO3 nanoparticles were also confirmed by Raman and TEM analyses. The obtained surface area (∼63-33 m(2)/g) of magnetron sputtered WO3 nanoparticles was found to be enhanced significantly as compared to reported surface area of WO3 nanoparticles synthesis by various techniques. The study of degradation reactions of CEES and DMMP on the surface of obtained nanoparticles was carried out by using GC and GC-MS techniques. The decontamination reactions were found to be pseudo first order steady state with rate constant (k) and half life values 0.143-0.109 h(-1) and 4.82-6.49 h for CEES and 0.018-0.010 h(-1) and 36.87-66.65 h for DMMP, respectively. The FT-IR data reveal the role of hydrolysis reactions in the decontamination of CEES as well as DMMP. PMID:25965433

  11. Detection of a nerve agent simulant using single-walled carbon nanotube networks: dimethyl-methyl-phosphonate

    NASA Astrophysics Data System (ADS)

    Kim, Yeonju; Lee, Seunghyun; Choi, Hyang Hee; Noh, Jin-Seo; Lee, Wooyoung

    2010-12-01

    Single-walled carbon nanotube (SWNT) networks were used to detect hazardous dimethyl-methyl-phosphonate (DMMP) gas in real time, employing two different metals as electrodes. Random networks of SWNTs were simply obtained by drop-casting a SWNT-containing solution onto a surface-oxidized Si substrate. Although the electrical responses to DMMP at room temperature were reversible for both metals, the Pd-contacting SWNT network sensors exhibited a higher response and a shorter response time than those of the Au-contacting SWNT network sensors at the same DMMP concentration, due to the stronger interactions between the SWNTs and Pd surface atoms. In Pd-contacting SWNT network sensors, the response increased linearly with increasing DMMP concentration and reproducible response curves were obtained for DMMP levels as low as 1 ppm. These results indicate that SWNT networks in contact with Pd electrodes can function as good DMMP sensors at room temperature with scalable and fast response and excellent recovery.

  12. A Molecular Dynamics Study of Tributyl Phosphate and Diamyl Amyl Phosphonate Self-Aggregation in Dodecane and Octane.

    PubMed

    Servis, Michael J; Tormey, Caleb A; Wu, David T; Braley, Jenifer C

    2016-03-17

    A molecular dynamics model for tributyl phosphate (TBP) and diamyl amyl phosphonate (DAAP) is presented using the Generalized AMBER Force Field (GAFF) and the AM1-BCC method for calculated atomic charges with a modification to the phosphorus-containing dihedral parameters. The density and average molecular dipole in a neat liquid simulation, and dimerization in dodecane and octane diluents, compare favorably to experimental values. At low extractant concentration, investigation of the dimer structure reveals the offset "head-to-head" orientation as the predominant structure over a range of TBP and DAAP concentrations with a phosphoryl oxygen separation distance between dimerized extractants of 3-5.5 Å. At high extractant concentrations, a graph analysis of extractant aggregates was used to determine concentrations of each aggregate size and the average coordination number, which gives a measure of the linearity of the aggregates. For aggregates up to 7 extractant molecules, the mean free energy of association per molecule was found to be 0.55-0.59 and 0.72 kcal/mol for TBP and DAAP, respectively. In both diluents, TBP formed large aggregates more frequently than DAAP, and those aggregates were more nonlinear than their DAAP equivalents. This finding anticipates differences in aggregation chemistry between TBP and DAAP in PUREX extraction systems. PMID:26886767

  13. Structure-Property Relationship of Layered Metal Oxide Phosphonate/Chitosan Nanohybrids for Transducer in Biosensing Device

    NASA Astrophysics Data System (ADS)

    De, Sriparna; Mohanty, Smita; Nayak, Sanjay Kumar

    2015-01-01

    A candid approach to analyze the performance characteristics of phenyl phosphonate-functionalized zirconium oxide and pure zirconium oxide (ZrO2) fillers reinforced chitosan nanocomposites and their suitability as a potential biomaterial for the development of transducer surface in biosensing device has been investigated in this communication. Functionalization of ZrO2 has been carried out using sulfophenylphosphonate which was confirmed using Fourier transform infrared spectrographs. The electrostatic intercalation of chitosan with filler particles was monitored using electrochemical impedance analyzer which exhibits lowest bulk resistance which is highly effective for ionic switching. Incorporation of zirconium sulfophenylphosphonate (ZrSP) the ionic conductivity of the chitosan film attained a value of 1.2 × 10-6 S/cm as compared to the unmodified one which is a prefeasibility work for the fabrication of biosensing platform. Variation in performance characteristics has been evaluated through morphological and thermal characterization. TGA and DSC analysis reveal that the thermal stability and decomposition temperature of the nanocomposites were improved by the addition of reinforcing filler particles. XRD and SEM and TEM results support the above assumption. The continuous alignment of the proton transfer channels of the nanocomposites was thoroughly investigated by AFM analysis which revealed phase morphology for improved enzyme entrapment. Further, surface functionalized nanofillers result considerable increment of mechanical properties in terms of elastic modulus and tensile stress.

  14. New N-acetyltransferase fold in the structure and mechanism of the phosphonate biosynthetic enzyme FrbF.

    PubMed

    Bae, Brian; Cobb, Ryan E; DeSieno, Matthew A; Zhao, Huimin; Nair, Satish K

    2011-10-14

    The enzyme FrbF from Streptomyces rubellomurinus has attracted significant attention due to its role in the biosynthesis of the antimalarial phosphonate FR-900098. The enzyme catalyzes acetyl transfer onto the hydroxamate of the FR-900098 precursors cytidine 5'-monophosphate-3-aminopropylphosphonate and cytidine 5'-monophosphate-N-hydroxy-3-aminopropylphosphonate. Despite the established function as a bona fide N-acetyltransferase, FrbF shows no sequence similarity to any member of the GCN5-like N-acetyltransferase (GNAT) superfamily. Here, we present the 2.0 Å resolution crystal structure of FrbF in complex with acetyl-CoA, which demonstrates a unique architecture that is distinct from those of canonical GNAT-like acetyltransferases. We also utilized the co-crystal structure to guide structure-function studies that identified the roles of putative active site residues in the acetyltransferase mechanism. The combined biochemical and structural analyses of FrbF provide insights into this previously uncharacterized family of N-acetyltransferases and also provide a molecular framework toward the production of novel N-acyl derivatives of FR-900098. PMID:21865168

  15. Separation of americium from europium by solvent extraction from aqueous phosphonate media

    SciTech Connect

    Ensor, D.D.; Nash, K.L.

    1994-12-31

    Complexes between Am{sup 3+} or Eu{sup 3+} and phosphonoacetic acid differ in relative stability in accord with the electrostatic model of cation binding. The smaller Eu{sup 3+} cation forms stronger complexes with PAA than the larger Am{sup 3+} cation. The observed metal complexes in the acid range from 0.005 M to 0.02 M (at I= 0.5 M) are Eu(HL){sup +}, Eu(H{sub 3}L){sub 2}{sup +}, Eu(HL){sub 2}{sup {minus}} and Am(H{sub 2}L){sup 2+}, Am(HL){sup +}, Am(H{sub 2}L){sub 2}{sup +}. When used as a holdback reagent, PAA slightly enhances the separation of Am/Eu when used with sulfonic acids or CMPO/nitrate, but reduces separation efficiency with HDEHP. In a CMPO/SCN{sup {minus}} extraction system which favors extraction of Am over Eu, addition of PAA increases the separation efficiency by a factor of 2-3 at 0.3 M PAA/0.5 M SCN{sup {minus}}. The calculated stability constants can be used to explain the separation factors, but do not always accurately predict metal distribution ratios in the CMPO systems, implying that there are details of this system which have not been fully elucidated.

  16. The chemolithoautotroph Acidithiobacillus ferrooxidans can survive under phosphate-limiting conditions by expressing a C-P lyase operon that allows it to grow on phosphonates.

    PubMed

    Vera, Mario; Pagliai, Fernando; Guiliani, Nicolas; Jerez, Carlos A

    2008-03-01

    The chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans is of great importance in biomining operations. During the bioleaching of ores, microorganisms are subjected to a variety of environmental stresses and to the limitations of some nutrients, such as inorganic phosphate (P(i)), which is an essential component for all living cells. Although the primary source of phosphorus for microorganisms is P(i), some bacteria are also able to metabolize P(i) esters (with a C-O-P bond) and phosphonates (with a very inert C-P bond). By using bioinformatic analysis of genomic sequences of the type strain of A. ferrooxidans (ATCC 23270), we found that as part of a Pho regulon, this bacterium has a complete gene cluster encoding C-P lyase, which is the main bacterial enzyme involved in phosphonate (Pn) degradation in other microorganisms. A. ferrooxidans was able to grow in the presence of methyl-Pn or ethyl-Pn as an alternative phosphorus source. Under these growth conditions, a great reduction in inorganic polyphosphate (polyP) levels was seen compared with the level for cells grown in the presence of P(i). By means of reverse transcription-PCR (RT-PCR), DNA macroarrays, and real-time RT-PCR experiments, it was found that A. ferrooxidans phn genes were cotranscribed and their expression was induced when the microorganism was grown in methyl-Pn as the only phosphorus source. This is the first report of phosphonate utilization in a chemolithoautotrophic microorganism. The existence of a functional C-P lyase system is a clear advantage for the survival under P(i) limitation, a condition that may greatly affect the bioleaching of ores. PMID:18203861

  17. Organocatalytic Asymmetric Michael/Cyclization Cascade Reactions of 3-Hydroxyoxindoles/3-Aminooxindoles with α,β-Unsaturated Acyl Phosphonates for the Construction of Spirocyclic Oxindole-γ-lactones/lactams.

    PubMed

    Chen, Lin; Wu, Zhi-Jun; Zhang, Ming-Liang; Yue, Deng-Feng; Zhang, Xiao-Mei; Xu, Xiao-Ying; Yuan, Wei-Cheng

    2015-12-18

    Enantioselective Michael/cyclization cascade reactions of 3-hydroxyoxindoles/3-aminooxindoles with α,β-unsaturated acyl phosphonates by using a cinchonine derived squaramide as the catalyst were developed. A broad range of spirocyclic oxindole-γ-lactones/lactams could be obtained in moderate to excellent yields (up to 98%) with good to excellent diastereo- and enantioselectivities (up to >99:1 dr and 97% ee) under mild conditions. This work represents the first example about the α,β-unsaturated acyl phosphonates for the asymmetric construction of spirocyclic oxindoles. PMID:26550839

  18. Proton Conduction in a Phosphonate-Based Metal–Organic Framework Mediated by Intrinsic “Free Diffusion inside a Sphere”

    PubMed Central

    2016-01-01

    Understanding the molecular mechanism of proton conduction is crucial for the design of new materials with improved conductivity. Quasi-elastic neutron scattering (QENS) has been used to probe the mechanism of proton diffusion within a new phosphonate-based metal–organic framework (MOF) material, MFM-500(Ni). QENS suggests that the proton conductivity (4.5 × 10–4 S/cm at 98% relative humidity and 25 °C) of MFM-500(Ni) is mediated by intrinsic “free diffusion inside a sphere”, representing the first example of such a mechanism observed in MOFs. PMID:27182787

  19. Human absorbed dose estimation for a new (175)Yb-phosphonate based on rats data: Comparison with similar bone pain palliation agents.

    PubMed

    Vaez-Tehrani, Mahdokht; Zolghadri, Samaneh; Yousefnia, Hassan; Afarideh, Hossein

    2016-09-01

    In this work, the absorbed dose to human organs for (175)Yb-BPAMD was evaluated based on the biodistribution studies in rats. The results showed that the bone surface would receive the highest absorbed dose after injection of (175)Yb-BPAMD with 13.32mGy/MBq, while the other organs receive insignificant absorbed dose. Also, the comparison of (175)Yb-BPAMD with other therapeutic phosphonate complexes demonstrated noticeable characteristics for this new agent. Generally, based on the obtained results, (175)Yb-BPAMD can be considered as a promising agent for bone pain palliative therapy in near future. PMID:27337650

  20. Recovery of phosphonate surface contaminants from glass using a simple vacuum extractor with a solid-phase microextraction fiber

    SciTech Connect

    Gary S. Groenewold; Jill R. Scott; Cathy Rae

    2011-07-01

    Recovery of chemical contaminants from fixed surfaces for analysis can be challenging particularly if it is not possible to acquire a solid sample. A simple device is described that collects semivolatile organic compounds from fixed surfaces by creating an enclosed volume over the surface, then generating a modest vacuum. A solid-phase microextraction fiber is then inserted into the evacuated volume where it functions to sorb volatilized organic contaminants. The device is based on a syringe modified with a seal that is used to create the vacuum, with a perforable plunger through which the SPME fiber is inserted. The vacuum speeds partitioning of the semivolatile compounds into the gas phase, and reduces the boundary layer around the SPME fiber, which enables a fraction of the volatilized organics to partition into the SPME fiber. After sample collection the SPME fiber is analyzed using conventional gas chromatography/mass spectrometry. The methodology has been used to collect organophosphorus compounds from glass surfaces, to provide a simple test for the functionality of the devices. Thirty minute sampling times (deltaTvac) resulted in fractional recovery efficiencies ranged from 10(-3) to > 10(-1), and in absolute terms collection of low nanograms was demonstrated. Fractional recovery values were correlated to the vapor pressure of the compounds being sampled. Fractional recovery increased with increasing deltaTvac, and displayed a roughly logarithmic profile indicating that an operational equilibrium is being approached. Fractional recovery decreased with increasing time between exposure and sampling, however recordable quantities of the phosphonates could be collected three weeks after exposure.