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1

Absorption of Carbon Dioxide in Aqueous Piperazine/Methyldiethanolamine  

E-print Network

Absorption of Carbon Dioxide in Aqueous Piperazine/Methyldiethanolamine Sanjay Bishnoi and Gary T dioxide absorption in 0.6 M piperazine PZ r4 M methyldiethanolamine ( )MDEA was measured in a wetted wall dioxide from synthesis gas in ammonia plants and hydrogenrcarbon Z .monoxide plants Wammes et al., 1994

Rochelle, Gary T.

2

Thermodynamics of Piperazine/Methyldiethanolamine/Water/Carbon Sanjay Bishnoi and Gary T. Rochelle*  

E-print Network

Thermodynamics of Piperazine/Methyldiethanolamine/Water/Carbon Dioxide Sanjay Bishnoi and Gary T though MDEA is present at much higher concentrations. Introduction Thermodynamics of aqueous amine are usually rate-controlling. Fur- thermore, a consistent thermodynamic model can quan- tify the energy

Rochelle, Gary T.

3

Aerobic biodegradability of methyldiethanolamine (MDEA) used in natural gas sweetening plants in batch tests and continuous flow experiments.  

PubMed

Mixtures of different amines including tertiary amines (methyldiethanolamine, MDEA) are commonly used for the removal of CO2 from gas mixtures or in gas sweetening processes for the extraction of CO2 and H2S. The absorber solutions used can be released into the industrial waste water due to continuous substitution of degraded MDEA, periodically cleaning processes or an accidental spill. In this study, the aerobic biodegradability of MDEA was investigated in a standardised batch test and a continuous flow experiment (40 l/d). The results of the batch test indicated that the MDEA-solution was non-biodegradable during the test period of 28 days, whereas the continuous flow experiments showed biodegradation of more than 96% based on TOC-measurements. This was probably due to the adaptation of the microorganisms to this particular waste water contamination during continuous flow experiment. PMID:12871741

Fürhacker, M; Pressl, A; Allabashi, R

2003-09-01

4

Molecular dynamics simulation studies of absorption in piperazine activated MDEA solution.  

PubMed

Development of more efficient solvent solutions for removal of CO(2) from natural gas and flue gases is a major task, which contributes to improved design of process plants and leads to decreased costs for its removal. Understanding the mechanisms of CO(2) absorption as well as analysis of undesired simultaneous processes is crucially important in this regard. In this work, we have applied Molecular Dynamics (MD) to investigate the absorption of CO(2) from a binary mixture of CO(2) and CH(4) into aqueous piperazine activated MDEA solution. The MD simulations were performed at a constant temperature of 298 K for five different systems with a loading factor of 0.07 to provide insight into molecular distribution in the amine solution and to enhance understanding of absorption mechanisms on the molecular scale. Force field parameters that were missing from the OPLS-AA force field, as well as charge distribution of piperazine (PZ), protonated piperazine (PZH(+)), piperazine carbamate (PZCOO(-)) and MDEA were obtained by QM calculations. The results of our simulations emphasize the importance of piperazine and piperazine carbamate in accelerating the absorption process. For the first time, we have shown the undesirable trapping of CH(4) by the amine solution and revealed that amine groups are mainly responsible for both absorption of CO(2) and the undesired trapping of CH(4). PMID:21691636

Farmahini, Amir Hajiahmadi; Kvamme, Bjørn; Kuznetsova, Tatiana

2011-07-28

5

Determination of rate constants for the reaction between methyldiethanolamine and carbon dioxide  

E-print Network

1985) Charles Meade Brabson, Jr. , B. S. , Virginia Polytechnic Institute and State University Chairman of Advisory Committee: Dr. J. A. Bullin The kinetics of the reaction between carbon dioxide (COz) and aqueous methyldiethanolamine (MDEA... Comparison of Observed Rate with Predicted Rates 75 8 Summary of Runs Using Three Percent Aqueous MEA Solution . 79 9 Comparison of Rate Constants for Second Order Reversible Model . . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 81 10 Summary...

Brabson, Charles Meade

2012-06-07

6

Determination of diethanolamine or N-methyldiethanolamine in high ammonium concentration matrices by capillary electrophoresis with indirect UV detection: application to the analysis of refinery process waters.  

PubMed

Alkanolamines such as diethanolamine (DEA) and N-methyldiethanolamine (MDEA) are used in desulfurization processes in crude oil refineries. These compounds may be found in process waters following an accidental contamination. The analysis of alkanolamines in refinery process waters is very difficult due to the high ammonium concentration of the samples. This paper describes a method for the determination of DEA in high ammonium concentration refinery process waters by using capillary electrophoresis (CE) with indirect UV detection. The same method can be used for the determination of MDEA. Best results were achieved with a background electrolyte (BGE) comprising 10 mM histidine adjusted to pH 5.0 with acetic acid. The development of this electrolyte and the analytical performances are discussed. The quantification was performed by using internal standardization, by which triethanolamine (TEA) was used as internal standard. A matrix effect due to the high ammonium content has been highlighted and standard addition was therefore used. The developed method was characterized in terms of repeatability of migration times and corrected peak areas, linearity, and accuracy. Limits of detection (LODs) and quantification (LOQs) obtained were 0.2 and 0.7 ppm, respectively. The CE method was applied to the determination of DEA or MDEA in refinery process waters spiked with known amounts of analytes and it gave excellent results, since uncertainties obtained were 8 and 5%, respectively. PMID:15338092

Bord, N; Crétier, G; Rocca, J-L; Bailly, C; Souchez, J-P

2004-09-01

7

Improvement of amine-modification with piperazine for the adsorption of CO2  

NASA Astrophysics Data System (ADS)

Both selectivity and capacity of CO2 adsorption were considerably increased when PZ (piperazine) was added in MDEA (methyldiethylamine) that used to modify the surface of silica gels. The adsorbent saturated with CO2 was regenerated at ambient temperature through nitrogen purge. A set of PSA (pressure swing adsorption) operation with 200 cycles was carried out and applicability of the modified adsorbent was thus illustrated. The CO2 content in the column-top stream decreased from 13% to below 0.05% at steady state.

Xue, Quanmin; Wu, Di; Zhou, Yaping; Zhou, Li

2012-02-01

8

The effect of phosphoric acid on the absorption of carbon dioxide into solutions of methyldiethanolamine  

E-print Network

the coabsorption of COz into MDEA solutions. The absorption of carbon dioxide into aqueous MDEA solutions is a mass- transfer process from the gas phase to the liquid phase followed by a chemical reaction. Several researchers, including Tomcej et ah (1989... the carbon dioxide reaction. The objective of this study is to determine whether the addition of small amounts of phosphoric acid (HsPO4) to aqueous MDEA will reduce the rate of CO2 absorption. This will be accomplished by determining comparative kinetic...

Cordi, Eric Marshall

2012-06-07

9

Piperazine-induced occupational asthma  

SciTech Connect

Asthmatic reactions were studied among some 130 factory workers who handled amines and other chemicals. Among present employees, we found 15 cases of asthma associated with occupational exposure to chemicals; among former employees there were at least 18. The inducing agent was judged to be piperazine in 29 persons and ethylenediamine (EDA) in three. The asthma was of the late or dual type; immediate reactions alone were to seen. No one had attacks of asthma before employment, and atopic subjects were not preferentially affected. Routine spirometry revealed airway obstruction in fewer than half of the recent cases. Tests of nonspecific bronchial reactivity with methacholine in six subjects with recent asthma showed hyperactivity in five, while tow subjects with earlier asthma did not have hyperactivity. Bronchial provocation tests with piperazine in one subject were positive both in the factory and in the laboratory. The level of piperazine was 1.2 mg/m3 time-weighted average (TWA) in a work place associated with induction of the asthmatic state, and 0.3 mg/m3 in a place connected with attacks in ''sensitized'' subjects.

Hagmar, L.; Bellander, T.; Bergoeoe, B.; Simonsson, B.G.

1982-03-01

10

Development of an analytical technique and construction of an apparatus to study the reaction between carbon dioxide and methyldiethanolamine  

E-print Network

dioxide (CO ) and methyldiethanolamine ( NDEA) in aqueous solu- 2 tions were investigated for two amine concentrations, temperatures from 80 to 150 F ( 27-66 C) and pressures o 0 from 100-270 psig (7. . 8-19. 4 atm). A gas-liquid contactor... and the froth spilled over a weir where the gas disengaged from the amine solution. Good material balance closure verified that the reactor could be used to obtain absorption rate data. The carbon dioxide and other components in the amine solution were...

Robbins, Gary Don

2012-06-07

11

Survey and Down-Selection of Acid Gas Removal Systems for the Thermochemical Conversion of Biomass to Ethanol with a Detailed Analysis of an MDEA System  

SciTech Connect

The first section (Task 1) of this report by Nexant includes a survey and screening of various acid gas removal processes in order to evaluate their capability to meet the specific design requirements for thermochemical ethanol synthesis in NREL's thermochemical ethanol design report (Phillips et al. 2007, NREL/TP-510-41168). MDEA and selexol were short-listed as the most promising acid-gas removal agents based on work described in Task 1. The second report section (Task 2) describes a detailed design of an MDEA (methyl diethanol amine) based acid gas removal system for removing CO2 and H2S from biomass-derived syngas. Only MDEA was chosen for detailed study because of the available resources.

Nexant, Inc., San Francisco, California

2011-05-01

12

John Arthur McLees, Jr. Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water at  

E-print Network

Copyright by John Arthur McLees, Jr. 2006 #12;Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water in Engineering The University of Texas at Austin May, 2006 #12;Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water

Rochelle, Gary T.

13

21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.  

Code of Federal Regulations, 2011 CFR

...Piperazine-carbon disulfide complex oral dosage forms. 520.1802...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS...Piperazine-carbon disulfide complex oral dosage...

2011-04-01

14

1-Benzhydryl-4-(4-chloro-phenyl-sulfonyl)piperazine  

PubMed Central

The title compound, C23H23ClN2O2S, was synthesized by the nucleophilic substitution of 1-benzhydrylpiperazine with 4-chloro­phenyl­sulfonyl chloride. The piperazine ring is in a chair conformation. The geometry around the S atom is that of a distorted tetra­hedron. There is a large range of bond angles around the piperazine N atoms. The dihedral angle between the least-squares plane (p1) defined by the four coplanar C atoms of the piperazine ring and the benzene ring is 81.6?(1)°. The dihedral angles between p1 and the phenyl rings are 76.2?(1) and 72.9?(2)°. The two phenyl rings make a dihedral angle of 65.9?(1)°. Intramolecular C—H?O hydrogen bonds are present. PMID:21201390

Girisha, H. R.; Naveen, S.; Vinaya, K.; Sridhar, M. A.; Shashidhara Prasad, J.; Rangappa, K. S.

2008-01-01

15

Theoretical study of differential enthalpy of absorption of CO2 with MEA and MDEA as a function of temperature.  

PubMed

Temperature dependent correlations for enthalpy of deprotonation, carbamate formation, and heat of absorption of the overall reaction between aqueous MEA and MDEA and gaseous CO2 are calculated on the basis of computational chemistry based ln K values input to the Gibbs-Helmholtz equation. Temperature dependency of reaction equilibrium constants for deprotonation and carbamate formation reactions is calculated with the SM8T continuum solvation model coupled with density functional theoretical calculations at the B3LYP/6-311++G(d,p) level of theory. Calculated reaction equilibrium constants and enthalpies of individual reactions and overall heat of absorption are compared against experimental data in the temperature range 273.15-373 K. Temperature dependent correlations for different reaction equilibrium constants and enthalpies of reactions are given. These correlated results can be used in thermodynamic models such as UNIQUAC and NRTL for better understanding of post-combustion CO2 capture solvent chemistry. PMID:23855311

Gupta, Mayuri; da Silva, Eirik F; Hartono, Ardi; Svendsen, Hallvard F

2013-08-15

16

Akinleye Olaolu Alawode Oxidative Degradation of Piperazine in the  

E-print Network

process parameters such as catalyst concentration, duration and agitation on degradation was studiedM/hr to 5mM/hr. The degradation rate was found to be dependent on agitation rate and catalyst concentration#12;Copyright by Akinleye Olaolu Alawode 2005 #12;Oxidative Degradation of Piperazine

Rochelle, Gary T.

17

Investigations on the stereoselectivity of the phase II metabolism of the 3,4-methylenedioxyethylamphetamine (MDEA) metabolites 3,4-dihydroxyethylamphetamine (DHEA) and 4-hydroxy-3-methoxyethylamphetamine (HMEA).  

PubMed

Different elimination was reported for the two enantiomers of the designer drug 3,4-methylenedioxyethylamphetamine (MDEA) in vivo. In the present work, the enantioselectivity of glucuronidation and sulfation of the MDEA phase I metabolites 3,4-dihydroxyethylamphetamine (DHEA) and 4-hydroxy-3-methoxyethylamphetamine (HMEA) was investigated. First, glucuronide standards were synthesized using rat liver microsomes. Incubations were performed with recombinant human UDP-glucuronyltransferases (UGT) and pooled human liver microsomes (pHLM) for glucuronidation and using recombinant human sulfotransferases (SULT) and pooled human liver cytosol (pHLC) for sulfation. Product formation experiments were performed by quantification of the phase II metabolites using liquid chromatography-high-resolution mass spectrometry. Additionally, substrate depletion experiments were conducted by gas chromatography-mass spectrometry after chiral derivatization for sulfation. UGT2B7, 2B15, and 2B17 were involved in glucuronidation of HMEA and SULT1A1 and SULT1A3 and SULT1A3 and SULT1E1 in the sulfation of DHEA and HMEA, respectively. SULTs provided much higher affinity, whereas UGTs showed higher capacities. Marked stereoselectivity could be observed for UGT2B15, UGT2B17, and pHLM toward S-HMEA, for SULT1A3 and pHLC toward S-DHEA and for SULT1A3 and pHLC toward R-HMEA. In conclusion, the phase II metabolism might also contribute to the observed different pharmacokinetic properties of MDEA. PMID:22564759

Schwaninger, Andrea E; Meyer, Markus R; Zapp, Josef; Maurer, Hans H

2012-07-01

18

Virtual Screening and Biological Evaluation of Piperazine Derivatives as Human Acetylcholinesterase Inhibitors  

PubMed Central

The piperazine derivatives have been shown to inhibit human acetylcholinesterase. Virtual screening by molecular docking of piperazine derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K), 4-(4-methyl)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S1), and 4-(4-chloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S3) has been shown to bind at peripheral anionic site and catalytic sites, whereas 4-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S4) and 4-(2,5-dichloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S7) do not bind either to peripheral anionic site or catalytic site with hydrogen bond. All the derivatives have differed in number of H-bonds and hydrophobic interactions. The peripheral anionic site interacting molecules have proven to be potential therapeutics in inhibiting amyloid peptides aggregation in Alzheimer's disease. All the piperazine derivatives follow Lipinski's rule of five. Among all the derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K) was found to have the lowest TPSA value. PMID:24288651

Varadaraju, Kavitha Raj; Kumar, Jajur Ramanna; Mallesha, Lingappa; Muruli, Archana; Mohana, Kikkeri Narasimha Shetty; Mukunda, Chethan Kumar; Sharanaiah, Umesha

2013-01-01

19

Thermodynamics of carbon dioxide in aqueous piperazine/potassium carbonate systems at stripper conditions  

E-print Network

GHGT-8 1 Thermodynamics of carbon dioxide in aqueous piperazine/potassium carbonate systems thermodynamic models. The range in CO2 solubility measured from 100 � 120 o C for K+ /PZ mixtures was from (0 and Technology to expand the thermodynamic data of for potassium carbonate/piperazine/CO2 with measurements of CO

Rochelle, Gary T.

20

Practical Synthesis of 1-(7-Fluoro-naphthalen-1-yl)piperazine Hydrochloride  

Microsoft Academic Search

A practical and scalable preparation of 1-(7-fluoronaphthalen-1-yl)-piperazine hydrochloride (1) is reported. The original route for the synthesis of this compound involved the use of 1-amino-7-fluoronaphthalene and bis(2-chloroethyl)amine hydrochloride, two highly toxic compounds. A new protocol has been developed that employs a palladium-catalyzed Buchwald–Hartwig cross-coupling reaction between 1-Boc-piperazine and 1-bromo-7-fluoronaphthalene followed by piperazine deprotection with HCl gas. In addition, an efficient

Javier Magano; Anne Akin; Michael H. Chen; Kendra Giza; Jennifer Moon; James Saenz

2008-01-01

21

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2012 CFR

...Significant New Uses for Specific Chemical Substances § 721.10102...piperazine (1:1). (a) Chemical substance and significant new...to reporting . (1) The chemical substance identified as...specified in § 721.80(j) (flame retardant). (ii)...

2012-07-01

22

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2013 CFR

...Significant New Uses for Specific Chemical Substances § 721.10102...piperazine (1:1). (a) Chemical substance and significant new...to reporting . (1) The chemical substance identified as...specified in § 721.80(j) (flame retardant). (ii)...

2013-07-01

23

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2010 CFR

...Significant New Uses for Specific Chemical Substances § 721.10102...piperazine (1:1). (a) Chemical substance and significant new...to reporting . (1) The chemical substance identified as...specified in § 721.80(j) (flame retardant). (ii)...

2010-07-01

24

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2011 CFR

...Significant New Uses for Specific Chemical Substances § 721.10102...piperazine (1:1). (a) Chemical substance and significant new...to reporting . (1) The chemical substance identified as...specified in § 721.80(j) (flame retardant). (ii)...

2011-07-01

25

Synthesis and Characterization of Piperazine-Modified Linseed Oil Fatty Amide Coatings  

Microsoft Academic Search

Piperazine-modified fatty amide (PMF) was prepared from N,N-bis(2 hydroxy ethyl) linseed oil fatty amide and piperazine through condensation polymerization. It was further cured with butylated melamine formaldehyde in different phr (parts per hundred part of resin) (PMF-BMF). PMF and PMF-BMF systems were subjected to spectroscopic analysis to ascertain their structure and curing scheme. Thermal studies and curing behavior of these

Sharif Ahmad; S. M. Ashraf; Manawwer Alam

2006-01-01

26

Solid-liquid equilibrium for mixtures containing cresols, piperazine, and dibutyl ether  

SciTech Connect

The solid-liquid phase diagrams have been determined for six binary and one ternary system composed of m-cresol, p-cresol, piperazine, and dibutyl ether. The results indicate the existence of 1-2 complexes in the p-cresol + m-cresol, piperazine + m-cresol, and piperazine + p-cresol systems. The observed melting points were correlated with composition by an empirical equation. Dissociation extractive crystallization is one of the potential methods for separating a compound from close boiling point mixtures such as p-cresol + 2,6-xylenol (1) and m-cresol + p-cresol systems. Gaikar et al. reported that using piperazine as a neutralizing agent and dibutyl ether as a solvent enables the recovery of 91% of p-cresol from a m-cresol + p-cresol mixture. This attractive method is of interest for further investigations. This attractive method is of interest for further investigations. To obtain better insight into this separation process, the authors measured the melting points of the mixtures composed of m-cresol, p-cresol, piperazine, and dibutyl ether by the solid-disappearance method over a temperature range from 246 and 382 K and atmospheric pressure.

Mingjer Lee; Peichi Chi (National Taiwan Inst. of Tech., Taipei (Taiwan, Province of China))

1993-04-01

27

1-Tosyl-4-[2-(trifluoro-meth-yl)benz-yl]piperazine  

PubMed Central

In the crystal structure of the title compound, C19H21F3N2O2S, the piperazine ring adopts a chair conformation. The dihedral angles between the mean plane of the piperazine ring and the tosyl and trifluoro­methyl­phenyl rings are 74.52?(3) and 68.30?(2)°, respectively. The sulfonamide N atom deviates from the plane defined by the three attached atoms by 0.327?(1)?Å. The crystal structure is stabilized by weak C—H?? inter­actions. PMID:23424518

Sreenivasa, S.; Anitha, H. C.; ManojKumar, K. E.; Tonannavar, J.; Jayashree, Yenagi; Suchetan, P. A.; Palakshamurthy, B. S.

2013-01-01

28

Cation-exchange high-performance liquid chromatographic assay of piperazine in some pharmaceutical formulations  

Microsoft Academic Search

An assay method for the quality control of piperazine in some formulations was developed utilizing cation-exchange high-performance liquid chromatography. A sample solution, containing 1-phenylpropanolamine-HCl as internal standard, was chromatographed on a 250 × 4.6 mm I.D. Ultrasil CX column with an aqueous mobile phase containing 0.07 M KH2PO4 (pH 3.0)-triethylamine (100:0.01), and differential refractive index detection. Piperazine and 1-phenylpropanolamine-HCl eluted

Henry S. I. Tan; Jianling Xu; Yaohan Zheng

1995-01-01

29

1-Phenyl-piperazine-1,4-diium tetra-chlorido-cobalt(II)  

PubMed Central

In the title mol­ecular salt, (C10H16N2)[CoCl4], the piperazine ring of the phenyl­piperazine dication adopts a chair conformation and the phenyl ring occupies an equatorial orientation. In the tetra­chlorido­cobaltate(II) dianion, the Co—Cl bond lengths for the chloride ions not accepting hydrogen bonds are significantly shorter than those for the chloride ions accepting such bonds. In the crystal, the components are linked by N—H?Cl hydrogen bonds, generating [001] chains. PMID:24826100

Dhieb, Abdelhamid Chiheb; Janzen, Daron E.; Rzaigui, Mohamed; Smirani Sta, Wajda

2014-01-01

30

Advanced Amine Solvent Formulations and Process Integration for Near-Term CO2 Capture Success  

SciTech Connect

This Phase I SBIR project investigated the economic and technical feasibility of advanced amine scrubbing systems for post-combustion CO2 capture at coal-fired power plants. Numerous combinations of advanced solvent formulations and process configurations were screened for energy requirements, and three cases were selected for detailed analysis: a monoethanolamine (MEA) base case and two “advanced” cases: an MEA/Piperazine (PZ) case, and a methyldiethanolamine (MDEA) / PZ case. The MEA/PZ and MDEA/PZ cases employed an advanced “double matrix” stripper configuration. The basis for calculations was a model plant with a gross capacity of 500 MWe. Results indicated that CO2 capture increased the base cost of electricity from 5 cents/kWh to 10.7 c/kWh for the MEA base case, 10.1 c/kWh for the MEA / PZ double matrix, and 9.7 c/kWh for the MDEA / PZ double matrix. The corresponding cost per metric tonne CO2 avoided was 67.20 $/tonne CO2, 60.19 $/tonne CO2, and 55.05 $/tonne CO2, respectively. Derated capacities, including base plant auxiliary load of 29 MWe, were 339 MWe for the base case, 356 MWe for the MEA/PZ double matrix, and 378 MWe for the MDEA / PZ double matrix. When compared to the base case, systems employing advanced solvent formulations and process configurations were estimated to reduce reboiler steam requirements by 20 to 44%, to reduce derating due to CO2 capture by 13 to 30%, and to reduce the cost of CO2 avoided by 10 to 18%. These results demonstrate the potential for significant improvements in the overall economics of CO2 capture via advanced solvent formulations and process configurations.

Fisher, Kevin S.; Searcy, Katherine; Rochelle, Gary T.; Ziaii, Sepideh; Schubert, Craig

2007-06-28

31

Atrazine removal by covalent bonding to piperazine functionalized PolyHIPEs  

Microsoft Academic Search

The removal of atrazine from water by a solid phase extraction technique using insoluble polymers is described. Porous crosslinked polymers bearing piperazine moieties were prepared in a one step reaction from the precursor 4-nitrophenylacrylate incorporating polymers (PolyHIPE type prepared by the polymerization of the continuous phase of a high internal phase emulsion and polymer beads prepared by suspension polymerization). Polymers

Irena Pulko; Mitja Kolar; Peter Krajnc

2007-01-01

32

Effects of piperazine derivatives on the activity of frog skeletal muscle fibers.  

PubMed

1. This study was undertaken to characterize the effects of some piperazine derivatives on excitable cell membranes. Three original Bulgarian compounds with favorable effects on cardiovascular and nervous system--piperazine derivatives with code names P-11 (N1-[3-oxo-3-phenyl-2-methyl-propyl]-N4-[trans-3-hydroxy-1,2,3,4- tetrahydro-2-naphthyl]-piperazine dihydrochloride), AS2 (N1-benzhydryl-N4-allyl piperazine dihydrochloride) and 35-M (Schiff's base of N1-benzhydryl-N4-aminopiperazine with triacetonamine, dioxalate salt) were tested in experiments with conventional microelectrode technique on isolated frog muscle fibers. 2. After 30-min treatment with tested drugs at concentrations of 10-100 microM the recorded intra-(ICAP) and extracellular action potentials (ECAPs) showed an amplitude decrease and duration increase. The total ionic current (Ii) decreased as the outward phase was almost abolished by P-11. The propagation velocity (PV) of excitation and the twitch amplitude also decreased. These changes were agent- and concentration-dependent. 3. The effect potency of the agents diminished in the following order: P-11 > AS2 > 35-M. 4. Concentrations higher than 100 microM for all agents completely, but reversibly, inhibited membrane excitability. 5. The results demonstrate compound- and concentration-induced modulation of Ca2+ current with blockade of Ca(2+)-dependent K+ and Cl- membrane channels of muscle fiber treated with the compound tested. PMID:7590143

Radicheva, N; Vydevska, M; Mileva, K

1995-10-01

33

New metal phosphonates containing coordination piperazine or pyridyl groups  

SciTech Connect

Reactions of transition metal(II) salts with three aminophosphonic acids, 1-[(H{sub 2}O{sub 3}PCH{sub 2}){sub 2}NCH{sub 2}CH{sub 2}-]-piperazine-4-CH{sub 2}PO{sub 3}H{sub 2} (H{sub 6}L{sup 1}), 3-pyridyl-CH{sub 2}N(CH{sub 2}PO{sub 3}H{sub 2}){sub 2} (H{sub 4}L{sup 2}) and 4-pyridyl-CH{sub 2}N(CH{sub 2}PO{sub 3}H{sub 2}){sub 2} (H{sub 4}L{sup 3}) afforded three new metal phosphonates, namely, Cu(H{sub 4}L{sup 1}).2H{sub 2}O (1), Co(H{sub 3}L{sup 2}){sub 2}.H{sub 2}O (2) and [Co(H{sub 2}L{sup 3})(H{sub 2}O)].H{sub 2}O (3). The structure of compound 1 features a 1D chain in which the CuN{sub 2}O{sub 3} and CPO{sub 3} polyhedra are interconnected by bridging phosphonate ligands to form 1D chains. Compound 2 has a layered structure. The cobalt(II) ions in the octahedral coordination geometries and {l_brace}CPO{sub 3}{r_brace} tetrahedra are interconnected into an inorganic chain via -N(CH{sub 2}PO{sub 3}H){sub 2} moieties, and adjacent chains are further bridged by the coordination pyridyl groups of H{sub 3}L{sup 2} into a 2D layer. The structure of compound 3 features a 2D double layered structure, in which the Co(II) ions are interconnected by bridging phosphonate groups into a 1D chain along b-axis. Neighboring chains are interconnected by coordination pyridyl groups into a double layer perpendicular to the c-axis.

Song Junling [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Mao Jianggao [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)]. E-mail: mjg@ms.fjirsm.ac.cn

2005-11-15

34

Kinetics of carbon dioxide absorption and desorption in aqueous alkanolamine solutions using a novel hemispherical contactor—I. Experimental apparatus and mathematical modeling  

Microsoft Academic Search

This two-parts paper summarizes the experimental and theoretical results of a comprehensive and first of its kind study on the kinetics of carbon dioxide (CO2) absorption and desorption in and from aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), methyl-diethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) and their mixtures (i.e., MEA+AMP, MEA+MDEA, DEA+AMP and DEA+MDEA). Part-1 of this paper presents a detailed design

Aqil Jamal; Axel Meisen; C. Jim Lim

2006-01-01

35

Copper(I) Cyanide Networks: Synthesis, Structure, and Luminescence Behavior. Part 2. Piperazine Ligands and Hexamethylenetetramine1  

E-print Network

Copper(I) Cyanide Networks: Synthesis, Structure, and Luminescence Behavior. Part 2. Piperazine-organic network chemistry of copper(I) cyanide with bridging nitrogen ligands (L).1­3 Because a single cyanide

Pike, Robert D.

36

Crystal structure of 3-[4-(pyrimidin-2-yl)piperazin-1-ium-1-yl]butano-ate  

PubMed Central

The title compound, C12H18N4O2, crystallizes in the zwitterionic form with protonation at the N atom of the piperazine ring bearing the carboxylate group. The piperazine ring adopts a slightly distorted chair conformation. In the crystal, N—H?O hydrogen bonds are observed, forming chains along [010]. The packing is consolidated by C—H?O inter­actions, which generate a three-dimensional network.

Yamuna, Thammarse S.; Jasinski, Jerry P.; Kaur, Manpreet; Anderson, Brian J.; Yathirajan, H.S.

2014-01-01

37

N-Substituted Piperazines Abused by Humans Mimic the Molecular Mechanism of 3,4-Methylenedioxymethamphetamine (MDMA, or ‘Ecstasy’)  

Microsoft Academic Search

3,4-Methylenedioxymethamphetamine (MDMA, or ‘Ecstasy’) is an illicit drug that stimulates the release of serotonin (5-HT) and dopamine (DA) from neurons. Recent evidence reveals that drug users are ingesting piperazine analogs, like 1-benzylpiperazine (BZP, or ‘A2’) and 1-(m-trifluoromethylphenyl)piperazine (TFMPP, or ‘Molly’), to mimic psychoactive effects of MDMA. In the present study, we compared the neurochemistry of MDMA, BZP, and TFMPP in

Michael H Baumann; Robert D Clark; Allison G Budzynski; John S Partilla; Bruce E Blough; Richard B Rothman

2005-01-01

38

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes  

Microsoft Academic Search

A novel tetradentate salicylic acid–formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, 1H NMR and electronic spectral

Shamim Ahmad Khan; Nahid Nishat; Shadma Parveen; Raza Rasool

2011-01-01

39

Potent piperazine hydroxyethylamine HIV protease inhibitors containing novel P3 ligands.  

PubMed

The 2-isopropyl thiazolyl group is a highly optimized P3 ligand for C2 symmetry-based HIV protease inhibitors, as exemplified in the drug ritonavir. Here we report that incorporation of this P3 ligand into a piperazine hydroxyethylamine series also yielded novel, highly potent inhibitors. In tissue culture assays, the presence of human serum was less deleterious to the activity of these inhibitors than to that of ritonavir. Furthermore, potent activity against ritonavir resistant HIV was observed. PMID:9934466

Chen, X; Kempf, D J; Sham, H L; Green, B E; Molla, A; Korneyeva, M; Vasavanonda, S; Wideburg, N E; Saldivar, A; Marsh, K C; McDonald, E; Norbeck, D W

1998-12-15

40

Bis{4-[(1,3-benzodioxol-5-yl)meth-yl]piperazin-1-yl}methane  

PubMed Central

In the title compound, C25H32N4O4, both piperazine rings adopt a chair conformation. One of dioxolane ring systems is essentially planar [dihedral angle = 0.9?(2)°] while the other adopts a slightly disordered envelope conformation, the mean plane of the dioxolane ring being twisted by 3.6?(2)° from that of the benzene ring. The dihedral angle between the benzene rings is 69.9?(5)°. No classical hydrogen bonds were observed. PMID:24454103

Kavitha, Channappa N.; Jasinski, Jerry P.; Anderson, Brian J.; Yathirajan, H. S.; Kaur, Manpreet

2013-01-01

41

1-Isopropyl-4-tosyl-piperazin-1-ium trifluoro-acetate.  

PubMed

In the title compound, C(14)H(23)N(2)O(2)S(+)·C(2)F(3)O(2) (-), the piperazine ring adopts a chair conformation. The crystal packing is stabilized by C-H?O and N-H?O hydrogen bonds between the cation and anion. The F atoms are disordered over two positions; the site occupancy factors are 0.55?(2) and 0.45?(2). PMID:21200786

Li, Jiang-Sheng; Yang, Dao-Wu; Liu, Wei-Dong

2007-01-01

42

Studies in piperazine containing poly(sulphone-amide)s for use in water desalination  

Microsoft Academic Search

Poly(sulphone-amide) polymers were prepared from reactions of 4,4?-diaminodiphenylsulphone (DDS) and piperazine with isophthaloyl chloride (ICl) or terephthaloyl chloride (TCl) in N-methylpyrollidone (NMP) by low temperature polycondensation. Properties such as inherent viscosity, percent moisture regain, percent solubility in different solvents, chlorine absorbance and thermal analysis were studied. Membranes were cast from solutions of these polymers in N, N?-dimethylacetamide (DMAC) containing dissolved

M. V. Biware; N. D. Ghatge

1995-01-01

43

Applications of quantitative structure-activity relationships to drug design of piperazine derivatives  

Microsoft Academic Search

Applications of quantitative structure-activity relationship (QSAR) procedures to our own practical drug research are reviewed. A benzylpiperazine cerebral vasodilator (KB-2796) and a piperazine-acetate antiulcer agent (KB-5492) were successfully optimized by use of QSAR information. In these cases, appropriate strategies of the synthetic research were devised and QSAR analyses were performed repeatedly in each step during the research. In the last

Hiroshi Ohtaka

1995-01-01

44

A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives  

PubMed Central

Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion®) and levocetirizine (Xyzal®) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed®), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening®) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad®) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up

2013-01-01

45

A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives.  

PubMed

Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion®) and levocetirizine (Xyzal®) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed®), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening®) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad®) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up; Kim, Sae-Hoon

2013-10-01

46

Electrophysiological effects of piperazine and diethylcarbamazine on Ascaris suum somatic muscle.  

PubMed Central

1 Electrophysiological recordings were made from the bag region of Ascaris suum muscle. Membrane potential and input conductance or membrane current under voltage clamp were measured. 2 In high-Cl- Ringer, bath-applied piperazine, at concentrations greater than 10(-4)M, produced a dose-dependent and reversible increase in input conductance associated with a hyperpolarizing potential. The increase in input conductance was reduced when the preparations were bathed in low-Cl- Ringer. Gamma-Aminobutyric acid (GABA) and piperazine reversal potentials were measured with a voltage clamp on the same cells using iontophoretic application of the agonists. The reversal potentials were the same and close to the predicted Nernst Cl- potential (-65 mV). When GABA and piperazine were applied simultaneously piperazine reversibly reduced the amplitude of the control outward GABA current response. It was concluded that piperazine acts as a GABA agonist of low potency on the extra-synaptic GABA receptors of the bag, mediating an increase in Cl- conductance. 3 Acetylcholine was applied iontophoretically within 100 micron of the bag region while the preparation was bathed in a low-Ca2+, low-Cl- Ringer. The response under voltage clamp was a dose-dependent inward current associated with an increase in input conductance. This response was reversibly antagonized by 3 X 10(-5)M tubocurarine, high concentrations of diethylcarbamazine (10(-3) to 10(-2)M) but not high concentrations of piperazine (10(-3) to 10(-2)M). It was concluded that there are extra-synaptic acetylcholine receptors on the bag region of Ascaris muscle and that diethylcarbamazine but not piperazine acts as an antagonist. 4 Bath-applied diethylcarbamazine (10(-4) to 2 X 10(-3)M) produced a reversible dose-dependent depolarization of the membrane potential which was associated with an increase in the amplitude and frequency of spontaneous depolarizing potentials in active preparations at 32 degrees C to 35 degrees C in high-Cl- Ringer. The excitatory action of diethylcarbamazine was not blocked by 3 X 10(-5)M tubocurarine. Diethylcarbamazine (10(-4) to 10(-3)M) had no effect on the outward current response to GABA iontophoresis. Diethylcarbamazine (10(-4) to 10(-2)M) reversibly antagonized in a dose-dependent manner the delayed rectification of the bag membrane. In a low-Ca2+, low-Cl- Ringer, diethylcarbamazine (10(-4) to 2 X 10(-3)M) reversibly antagonized the voltage-sensitive outward current of the bag. This effect was mimicked by high-K+ Ringer or perfusion with 4-aminopyridine (10(-3) to 2 X 10(-3)M). It was concluded that diethylcarbamazine did not react with the GABA receptor but antagonized a voltage-sensitive K+ conductance. PMID:7139188

Martin, R. J.

1982-01-01

47

Threaded structure and blue luminescence of (CuCN)20(Piperazine)7{ Robert D. Pike,* Kathryn E. deKrafft, Amanda N. Ley and Tristan A. Tronic  

E-print Network

Threaded structure and blue luminescence of (CuCN)20(Piperazine)7{ Robert D. Pike,* Kathryn E. de and highly luminescent 20 : 7 complex of CuCN with piperazine (Pip) was formed under aqueous conditions; its of luminescent metal­organic networks based on CuCN,9 we herein report the formation of a copper-rich network

Pike, Robert D.

48

2-[2-(4-Methyl-piperazin-1-yl)eth-yl]iso-indoline-1,3-dione  

PubMed Central

In the title compound, C15H19N3O2, the piperazine ring adopts a chair conformation, with its N—C bonds in pseudo-equatorial orientations. The dihedral angle between the C atoms of the piperazine ring and the phthalamide ring system (r.m.s. deviaiton = 0.008?Å) is 89.30?(8)°. In the crystal, mol­ecules are linked by C—H?O hydrogen bonds, generating a three-dimensional network and aromatic ?–? inter­actions also occur [centroid–centroid distances = 3.556?(1)–3.716?(1)?Å]. PMID:24764996

Zhou, Mi; Shao, Ying; Xia, Yong-an; Liu, Xiao-Long; Sun, Xiao-Qiang

2014-01-01

49

Synthesis of aluminium complexes bearing a piperazine-based ligand system  

Microsoft Academic Search

Aluminium complexes bearing the N,N-chelating ligand 1,4-bis(2-hydroxy-3,5-di-tert-butyl)piperazine (1) have been synthesised. Both monometallic and bimetallic aluminium methyl complexes (2 and 3, respectively) were prepared by treatment of 1 with the appropriate amount of AlMe3. Complex 2 can be converted to 3 by addition of excess AlMe3. Bimetallic aluminium-ethyl complex 4 was also prepared. Treatment of 1 with AlEt2Cl afforded the

Nick C. Johnstone; Elham S. Aazam; Peter B. Hitchcock; J. Robin Fulton

2010-01-01

50

Synthesis and antimicrobial evaluation of new chalcones containing piperazine or 2,5-dichlorothiophene moiety.  

PubMed

Two new series of chalcones have been synthesized by reacting 1-(4-piperazin-1-yl-phenyl)ethanone and 1-(2,5-dichloro-3-thienyl)-1-ethanone with different substituted benzaldehydes in turn by Claisen-Schmidt condensation. The compounds have been characterized by IR, (1)H NMR spectral and microanalysis data. All the synthesized compounds have been evaluated for antimicrobial activity. Some of these derivatives are potentially active against Gram-positive bacteria, Staphylococcus aureus and Escherichia coli while the most potent compound (1) in this study showed MIC(50) value of 2.22 microg/mL against Candida albicans. PMID:17719779

Tomar, V; Bhattacharjee, G; Kamaluddin; Kumar, Ashok

2007-10-01

51

4-(Furan-2-carbon-yl)piperazin-1-ium 3,5-di-nitro-benzoate  

PubMed Central

In the cation of the title salt, C9H13N2O2 +·C7H3N2O6 ?, the piperazine ring adopts a slightly distorted chair conformation. Twofold rotational disorder is exhibited by the furan ring in a 0.430?(4):0.570?(4) ratio. In the crystal, N—H?O hydrogen bonds link the ions into chains along [010]. Additional weak C—H?O inter­actions are observed, leading to a supra­molecular layer parallel to (011). PMID:24940274

Kavitha, Channappa N.; Kaur, Manpreet; Jasinski, Jerry P.; Butcher, Ray J.; Yathirajan, H.S.

2014-01-01

52

Kinetics of N-nitrosopiperazine formation from nitrite and piperazine in CO2 capture.  

PubMed

Piperazine (PZ) is an efficient amine for carbon capture systems, but it can form N-nitrosopiperazine (MNPZ), a carcinogen, from nitrogen oxides (NO(x)) in flue gas from coal or natural gas combustion. The reaction of nitrite with PZ was studied in 0.1 to 5 mol/dm(3) PZ with 0.001 to 0.8 mol CO2/mol PZ at 50 to 135 °C. The reaction forming MNPZ is first order in nitrite, piperazine carbamate species, and hydronium ion. The activation energy is 84 ± 2 kJ/mol with a rate constant of 8.5 × 10(3) ± 1.4 × 10(3) dm(6) mol(-2) s(-1) at 100 °C. The proposed mechanism involves protonation of the carbamate species, nucleophilic attack of the carbamic acid, and formation of bicarbonate and MNPZ. These kinetics and mechanism will be useful in identifying inhibitors and other strategies to reduce nitrosamine accumulation in CO2 capture by scrubbing with PZ or other amines. PMID:23438967

Goldman, Mark J; Fine, Nathan A; Rochelle, Gary T

2013-04-01

53

Synthesis and SAR of piperazine amides as novel c-jun N-terminal kinase (JNK) inhibitors  

PubMed Central

A novel series of c-jun N-terminal kinase (JNK) inhibitors were designed and developed from a high-throughput-screening hit. Through the optimization of the piperazine amide 1, several potent compounds were discovered. The X-ray crystal structure of 4g showed a unique binding mode different from other well known JNK3 inhibitors. PMID:19433357

Shin, Youseung; Chen, Weiming; Habel, Jeff; Duckett, Derek; Ling, Yuan Yuan; Koenig, Marcel; He, Yuanjun; Vojkovsky, Tomas; LoGrasso, Philip; Kamenecka, Theodore M.

2009-01-01

54

Synthesis and SAR of piperazine amides as novel c-jun N-terminal kinase (JNK) inhibitors  

SciTech Connect

A novel series of c-jun N-terminal kinase (JNK) inhibitors were designed and developed from a high-throughput-screening hit. Through the optimization of the piperazine amide 1, several potent compounds were discovered. The X-ray crystal structure of 4g showed a unique binding mode different from other well known JNK3 inhibitors.

Shin, Youseung; Chen, Weiming; Habel, Jeff; Duckett, Derek; Ling, Yuan Yuan; Koenig, Marcel; He, Yuanjun; Vojkovsky, Tomas; LoGrasso, Philip; Kamenecka, Theodore M.; (Scripps)

2009-09-14

55

Atrazine removal by covalent bonding to piperazine functionalized PolyHIPEs.  

PubMed

The removal of atrazine from water by a solid phase extraction technique using insoluble polymers is described. Porous crosslinked polymers bearing piperazine moieties were prepared in a one step reaction from the precursor 4-nitrophenylacrylate incorporating polymers (PolyHIPE type prepared by the polymerization of the continuous phase of a high internal phase emulsion and polymer beads prepared by suspension polymerization). Polymers were applied to sequester atrazine from aqueous solutions with a concentration of 33 ppb and irreversible covalent bonding to the polymers was achieved. GC/MS/MS was used to monitor the dynamics of atrazine uptake and it was found that almost complete removal of atrazine was accomplished with an excess of polymer after 48 hours at room temperature. For comparison, polymer beads of identical chemistry but lower porosity were also used and showed significantly slower action (near complete removal after 72 hours). PMID:17662371

Pulko, Irena; Kolar, Mitja; Krajnc, Peter

2007-11-01

56

(Z)-1-Di-phenyl-methyl-4-(3-phenyl-prop-2-en-yl)piperazine  

PubMed Central

In the title compound, C26H28N2, the piperazine group adopts a chair conformation with the exocyclic N—C bonds in equatorial orientations. The dihedral angle between the geminal benzene rings is 80.46?(12)° and the C=C—C—N torsion angle is 145.9?(2)°. In the crystal, weak C—H?? inter­actions link the mol­ecules into [100] chains. PMID:24860379

Shivaprakash, S.; Chandrasekara Reddy, G.; Jasinski, Jerry P.

2014-01-01

57

Piperazine-like compounds: a new group of designer drugs-of-abuse on the European market.  

PubMed

1-Aryl-piperazine compounds are, depending on their substituents, selective for certain serotonin receptors and together with their easy availability and their so-called legal status, this group of psychoactive compounds are potential designer drugs-of-abuse. Internet in that respect is an important source of information and distribution facilities. Because this development may have consequences for the interpretation of future clinical and forensic toxicological case studies, some analytical aspects of 1-benzyl-piperazine (BZP), 1-[4-methoxyphenyl]-piperazine (pMeOPP) and 1-[3-trifluoromethylphenyl]-piperazine (TFMPP) were studied. BZP was not detected by the AxSYM FPIA technology designed to determine amphetamine-like compounds, but had showed some cross reactivity with EMIT d.a.u.. The cross reactivities at 300 and 12,000ng/ml (RS)-amphetamine equivalents were 0.4 and 1.3%, respectively. Although BZP was not identified directly by the REMEDi HS Drug Profiling System, it can be detected by this HPLC/UV scanning system. Using GC/NPD without derivatisation, BZP, pMeOPP and TFMPP can be analysed for and applying GC/MS without or with acetylation or trifluoroacetylation, these compounds can be identified unambiguously. The usefulness of GC/NPD and GC/MS in this respect was demonstrated by the quantitative and qualitative analysis of the content of a capsule with the synthetic stimulant A2, which proved to contain 86.4mg of BZP. PMID:11516887

de Boer, D; Bosman, I J; Hidvégi, E; Manzoni, C; Benkö, A A; dos Reys, L J; Maes, R A

2001-09-15

58

Quantitative determination of some pharmaceutical piperazine derivatives through complexation with iron(III) chloride.  

PubMed

A simple, accurate and sensitive spectrophotometric method has been developed for the determination of three pharmaceutical piperazine derivatives, namely ketoconazole (KC), trimetazidine hydrochloride (TMH) and piribedil (PD). This method is based on the formation of yellow orange complexes between iron(III) chloride and the investigated drugs. The optimum reaction conditions, spectral characteristics, conditional stability constants and composition of the water soluble complexes have been established. The method permits the determination of KC, TMH and PD over a concentration range 1-15, 1-12 and 1-12 microg ml(-1), respectively. Sandell sensitivity is found to be 0.016, 0.013 and 0.013 microg cm(-2) for KC, TMH and PD, respectively. The method was sensitive, simple, reproducible and accurate within +/-1.5%. The method is applicable to the assay of the three drugs under investigation in different dosage forms and the results are in good agreement with those obtained by the official methods (USP and JP). PMID:12875888

Abou-Attia, F M; Issa, Y M; Abdel-Gawad, F M; Abdel-Hamid, S M

2003-08-01

59

Design, synthesis and evaluation of new thiazole-piperazines as acetylcholinesterase inhibitors.  

PubMed

In this study, some new 2-(4-substituted piperazine-1-yl)-N-[4-(2-methylthiazol-4-yl)phenyl]acetamide derivatives were synthesized. The synthesized compounds were screened for their anticholinesterase activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes by in vitro Ellman's method. The structural elucidation of the compounds was performed by using IR, (1)H-NMR, (13)C-NMR and FAB(+)-MS spectral data and elemental analyses results. Biological assays revealed that at 0.1 µM concentration, the most active compounds against AChE were 5n, 5o and 5p that indicated 96.44, 99.83 and 89.70% inhibition rates, respectively. Besides, IC50 value of the compound 5o was determined as 0.011 µM, whereas IC50 value of standard drug donepezil was 0.054 µM. The synthesized compounds did not show any notable inhibitory activity against BChE. PMID:22871134

Yurtta?, Leyla; Kaplanc?kl?, Zafer As?m; Özkay, Yusuf

2013-10-01

60

Corrosion in CO{sub 2} capture process using blended monoethanolamine and piperazine  

SciTech Connect

This work explores the promise of aqueous solutions of blended monoethanolamine (MEA) and piperazine (PZ) as a cost-effective solvent for carbon dioxide (CO{sub 2}) capture, from industrial flue gas streams with respect to corrosion, which is regarded as one of the, most severe operational problems in typical CO{sub 2} capture plants. Electrochemical corrosion experiments were carried out using the potentiodynamic polarization technique for corrosion measurements. The results show that the blended MEA/PZ solutions are more corrosive than the MEA solutions. The corrosion rate of carbon steel increases with concentration of PZ, total amine concentration, CO{sub 2} loading of solution, solution temperature, and the presence of heat stable salts. Among the tested heat-stable salts, formate is the most corrosive salt, followed by acetate, oxalate, and thiosulfate in the absence of oxygen (O{sub 2}), while acetate is the most corrosive salt followed by formate, oxalate, and thiosulfate in the presence of O{sub 2}.

Nainar, M.; Veawab, A. [University of Regina, Regina, SK (Canada). Faculty of Engineering

2009-10-15

61

Temperature- and pH-responsive nanoparticles of biocompatible polyurethanes for doxorubicin delivery.  

PubMed

A series of temperature- and pH-responsive polyurethanes based on hexamethylene diisocyanate (HDI) and 4,4'-diphenylmethane diisocyanate (MDI) were synthesized by a coupling reaction with bis-1,4-(hydroxyethyl) piperazine (HEP), N-methyldiethanolamine (MDEA) and N-butyldiethanolamine (BDEA), respectively. The chemical structure, molecular weight, thermal property and crystallization properties were characterized by Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) spectroscopy. The resulting polyurethanes were then used to prepare nanoparticles either by direct dispersion method or dialysis method. Their pH and temperature responsibilities were evaluated by optical transmittance and size measurement in aqueous media. Interestingly, HDI-based and MDI-based polyurethanes exhibited different pH and temperature responsive properties. Nanoparticles based on HDI-HEP and HDI-MDEA were temperature-responsive, while MDI-based biomaterials were not. All of them showed pH-sensitive behavior. The possible responsive mechanism was investigated by (1)H NMR spectroscopy. The cytotoxicity of the polyurethanes was evaluated using methylthiazoletetrazolium (MTT) assay in vitro. It was shown that the HDI-based polyurethanes were non-toxic, and could be applied to doxorubicin (DOX) encapsulation. The experimental results indicated that DOX could be efficiently encapsulated into polyurethane nanoparticles and uptaken by Huh-7 cells. The loaded DOX molecules could be released from the drug-loaded polyurethane nanoparticles upon pH and temperature changes, responsively. PMID:23262421

Wang, Anning; Gao, Hui; Sun, Yanfang; Sun, Yu-long; Yang, Ying-Wei; Wu, Guolin; Wang, Yinong; Fan, Yunge; Ma, Jianbiao

2013-01-30

62

Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.  

PubMed

Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals. PMID:25167095

McDonald, Jacob D; Kracko, Dean; Doyle-Eisele, Melanie; Garner, C Edwin; Wegerski, Chris; Senft, Al; Knipping, Eladio; Shaw, Stephanie; Rohr, Annette

2014-09-16

63

Formation of p-cresol:piperazine complex in solution monitored by spin-lattice relaxation times and pulsed field gradient NMR diffusion measurements  

NASA Astrophysics Data System (ADS)

A study of the nature of the anthelmintic p-cresol:piperazine complex in chloroform solution has been conducted using different NMR techniques: self-diffusion coefficients using DOSY; NOE, NULL, and double-selective T1 measurements to determine inter-molecular distances; and selective and non-selective T1 measurements to determine correlation times. The experimental results in solution and CP-MAS were compared to literature X-ray diffraction data using molecular modeling. It was shown that the p-cresol:piperazine complex exists in solution in a very similar manner as it does in the solid state, with one p-cresol molecule hydrogen bonded through the hydroxyl hydrogen to each nitrogen atom of piperazine. The close correspondence between the X-ray diffraction data and the inter-proton distances obtained by NULL and double selective excitation techniques indicate that those methodologies can be used to determine inter-molecular distances in solution.

de Carvalho, Erika Martins; Velloso, Marcia Helena Rodrigues; Tinoco, Luzineide Wanderley; Figueroa-Villar, José Daniel

2003-10-01

64

Effect of the piperazine unit and metal-binding site position on the solubility and anti-proliferative activity of ruthenium(II)- and osmium(II)- arene complexes of isomeric indolo[3,2-c]quinoline-piperazine hybrids.  

PubMed

In this study, the indoloquinoline backbone and piperazine were combined to prepare indoloquinoline-piperazine hybrids and their ruthenium- and osmium-arene complexes in an effort to generate novel antitumor agents with improved aqueous solubility. In addition, the position of the metal-binding unit was varied, and the effect of these structural alterations on the aqueous solubility and antiproliferative activity of their ruthenium- and osmium-arene complexes was studied. The indoloquinoline-piperazine hybrids L(1-3) were prepared in situ and isolated as six ruthenium and osmium complexes [(?(6)-p-cymene)M(L(1-3))Cl]Cl, where L(1) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-2-N-amine, M = Ru ([1a]Cl), Os ([1b]Cl), L(2) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-4-N-amine, M = Ru ([2a]Cl), Os ([2b]Cl), L(3) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-8-N-amine, M = Ru ([3a]Cl), Os ([3b]Cl). The compounds were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, ESI mass spectrometry, IR and UV-vis spectroscopy, and single-crystal X-ray diffraction. The antiproliferative activity of the isomeric ruthenium and osmium complexes [1a,b]Cl-[3a,b]Cl was examined in vitro and showed the importance of the position of the metal-binding site for their cytotoxicity. Those complexes containing the metal-binding site located at the position 4 of the indoloquinoline scaffold ([2a]Cl and [2b]Cl) demonstrated the most potent antiproliferative activity. The results provide important insight into the structure-activity relationships of ruthenium- and osmium-arene complexes with indoloquinoline-piperazine hybrid ligands. These studies can be further utilized for the design and development of more potent chemotherapeutic agents. PMID:24927493

Filak, Lukas K; Kalinowski, Danuta S; Bauer, Theresa J; Richardson, Des R; Arion, Vladimir B

2014-07-01

65

HS process: an advanced process for selective H/sub 2/S  

SciTech Connect

Union Carbide's HS process offers improved efficiency in both H/sub 2/S removal and system costs while remaining flexible to diverse gas-conditioning requirements. The process combines three principal elements - an MDEA (methyldiethanolamine) solvent, a multistaged contactor design, and a special selective contactor tray. Prototype pilot-plant operations have demonstrated the superior performance of the HS process over existing methods.

Sigmund, P.W.; Butwell, K.F.; Wussler, A.J.

1981-01-01

66

3-Chloro-6-{4-[3-(trifluoro-meth-yl)phen-yl]piperazin-1-yl}pyridazine.  

PubMed

The title compound, C(15)H(14)ClF(3)N(4), was synthesized from 3,6-dichloro-pyridazine and 1-[3-(trifluoro-meth-yl)phen-yl]piper-azine. The piperazine ring is flanked by 3-chloro-pyridazine and 3-trifluoro-methyl-phenyl rings and adopts a chair conformation, whereas the 3-chloro-pyridazine and 3-trifluoro-methyl-phenyl rings are planar, with maximum deviations of 0.0069?(13) and 0.0133?(14)?Å, respectively. The crystal structure is stabilized by weak inter-molecular C-H?N hydrogen-bond inter-actions. PMID:21580304

Arslan, Hakan; Utku, Semra; Hardcastle, Kenneth I; Gökçe, Mehtap; Lense, Sheri

2010-01-01

67

Tri- and tetraurea piperazine cyclophanes: synthesis and complexation studies of preorganized and folded receptor molecules.  

PubMed

A series of symmetrical tri- and tetrameric N-ethyl- and N-phenylurea-functionalized cyclophanes have been prepared in nearly quantitative yields (86-99?%) from the corresponding tri- and tetraamino-functionalized piperazine cyclophanes and ethyl or phenyl isocyanates. Their conformational and complexation properties have been studied by single-crystal X-ray diffraction, variable-temperature NMR spectroscopy, and ESI-MS analysis. The rigid 27-membered trimeric cyclophane skeleton assisted by a seam of intramolecular hydrogen bonds results in a preorganized ditopic recognition site with an all-syn conformation of the urea moieties that, complemented by a lipophilic cavity of the cyclophane, binds molecular and ionic guests as well as ion pairs. The all-syn conformation persists in acidic conditions and the triprotonated triurea cyclophane binds an unprecedented anion pair, H(2)PO(4)(-)???HPO(4)(2-), in the solid state. The tetra-N-ethylurea cyclophane is less rigid and demonstrates an induced-fit recognition of diisopropyl ether in the solid state. The guest was encapsulated within the lipophilic interior of a quasicapsule, formed by intramolecular hydrogen-bond-driven folding of the 36-membered cyclophane skeleton. In the gas phase, the essential role of the urea moieties in the binding was demonstrated by the formation of monomeric 1:1 complexes with K(+), TMA(+), and TMP(+) as well as the ion-pair complexes [KI+K](+), [TMABr+TMA](+) and [TMPBr+TMP](+). In the positive-mode ESI-MS analysis, ion-pair binding was found to be more pronounced with the larger tetraurea cyclophanes. In the negative mode, owing to the large size of the binding site, a general binding preference towards larger anions, such as the iodide, over smaller anions, such as the fluoride, was observed. PMID:21077059

Raatikainen, Kari; Beyeh, N Kodiah; Rissanen, Kari

2010-12-27

68

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes  

NASA Astrophysics Data System (ADS)

A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, 1H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.

Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

2011-10-01

69

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes.  

PubMed

A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, (1)H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand. PMID:21757398

Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

2011-10-15

70

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.  

PubMed

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid?pyridine heterosynthon and N-H?O catemer hydrogen bonds involving the amide group. The acid?amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl?carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24?h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug. PMID:25075330

Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

2014-03-01

71

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt  

PubMed Central

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid?pyridine heterosynthon and N—H?O catemer hydrogen bonds involving the amide group. The acid?amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl?carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24?h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug. PMID:25075330

Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

2014-01-01

72

Bis(1-methyl-piperazine-1,4-diium) di-?-bromido-bis-[tetra-bromido-bismuthate(III)] dihydrate  

PubMed Central

In the title hydrated salt, (C5H14N2)2[Bi2Br10]·2H2O, the com­plete [Bi2Br10]4? biocta­hedron is generated by crystallographic inversion symmetry. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position. In the crystal, the tetra­anions and water mol­ecules are linked by O—H?Br and O—H?(Br,Br) hydrogen bonds to generate [100] chains. The chains are crosslinked by N—H?Br, N—H?O and C—H?Br hydrogen bonds originating from the piperazinediium dications, thereby forming a three-dimensional network. PMID:24940195

Essid, Manel; Roisnel, Thierry; Marouani, Houda

2014-01-01

73

Luminescent cadmium phenylenediacetate coordination polymers with bis(pyridylformyl)piperazine tethers: Influence of pendant arm position on topology  

NASA Astrophysics Data System (ADS)

Hydrothermal synthesis has generated divalent cadmium coordination polymers containing phenylenediacetate (phda) and bis(4-pyridylformyl)piperazine (bpfp) ligands, in which the position of the pendant acetate arms plays a very significant role in structure direction during self-assembly. [Cd(1,2-Hphda) 2(4-bpfp)] n ( 1) exhibits 2-D polymeric layers with embedded anti-syn bridged [Cd(OCO) 2] n ribbons. {[Cd(1,3-phda)(4-bpfp)(H 2O)] 2} n ( 2) has crystallographically independent (4,4) grids with different carboxylate binding modes, engaged in parallel interpenetration. {[Cd(1,4-phda)(4-bpfp)(H 2O)]} n ( 3) manifests acentric 1-D chains with an uncommon 4-connected 3 34 25 topology instilled by the mismatch in ligand length. Luminescent properties of all phases are also reported.

Wang, Curtis Y.; LaDuca, Robert L.

2010-11-01

74

Thermodynamic Investigation and Mixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands.  

PubMed

Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and its metal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1?M NaNO(3)) using a potentiometric technique. The order of -?G(0) and -?H(0) was found to obey Co(2+) < Ni(2+) < Cu(2+) > Zn(2+), in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L?=?amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter ?log K. PMID:23226992

El-Sherif, Ahmed A; Shehata, Mohamed R; Shoukry, Mohamed M; Barakat, Mohammad H

2012-01-01

75

Pelanserin: 3-[3-(4-phenyl-piperazin-1-yl)prop-yl]quinazoline-2,4(1H,3H)-dione  

PubMed Central

The title compound, C21H24N4O2, is a potent serotonin 5-HT2 and ?1-adrenoceptor antagonist. The n-propyl chain links the quinazolinedione heterocycle and the phenyl­piperazine group in which the benzene ring is equatorially located and the piperazine ring has the expected chair conformation. The dihedral angle between the planes of the benzene ring and the quinazolinedione ring system is 74.1?(1)°. In the crystal, mol­ecules form centrosymmetric dimers through R 2 2(8) hydrogen-bonded rings involving the amine and one carbonyl group of the quinazolinedione moiety. These dimers are extended into chains extending along the a-axis direction through expanded centrosymmetric cyclic C—H?O associations involving the second carbonyl group, giving R 2 2(20) and R 1 2(7) motifs.

Aguirre Hernandez, Gerardo; Somanathan, Ratnasamy; Bernes, Sylvain

2014-01-01

76

Effects of repeated administration of the monoamine oxidase inhibitor phenelzine on the discriminability of d-lysergic acid diethylamide (LSD) and 1-(m-trifluoromethylphenyl) piperazine (TFMPP)  

Microsoft Academic Search

Rats trained to discriminate d-lysergic acid diethylamide (LSD; 0.08 mg\\/kg) or 1-(m-trifluoromethylphenyl) piperazine (TFMPP; 0.8 mg\\/kg) were treated with the monoamine oxidase inhibitor (MAOI) phenelzine (10 mg\\/kg\\/day) for 7 days. After a 24 h “washout” period, they were challenged with the training drug (and dose) or saline, during extinction test sessions. Following 0.08 mg\\/kg LSD, LSD-trained rats responded primarily on

Kathryn A. Cunningham; Brenda A. Carroll; James B. Appel

1986-01-01

77

Titanium(IV)-mediated synthesis of 2,3-diisothiocyanato-succinic acid diesters and 3,6-dithioxo-piperazine derivatives  

Microsoft Academic Search

Oxidative homocoupling of titanium(IV) enolates of 2-isothiocyanato-carboxylic esters resulted in the synthesis of 2,3-diisothiocyanato-succinic acid diesters. The reactions were carried out using DIPEA\\/TiCl4 oxidizing system and led to chiral dimers (instead of meso) as main products. Titanium(IV) enolates derived from hindered 2-isothiocyanato-carboxylates did not undergo the oxidative homocoupling but gave 3,6-dithioxo-piperazines.

Dariusz Cie?

2007-01-01

78

Absorption of carbon dioxide by the absorbent composed of piperazine and 2-amino-2-methyl-1-propanol in PVDF membrane contactor  

Microsoft Academic Search

This paper tests the performance of microporous polyvinylidinefluoride (PVDF) hollow fiber in a gas absorption membrane process (GAM) using the aqueous solutions of piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP). Experiments were conducted at various gas flow rates, liquid flow rates and absorbent concentrations. Experimental results showed that wetting ratio was about 0.036% when used with the aqueous alkanolamine solutions, while that

Su-Hsia Lin; Pen-Chi Chiang; Chun-Fan Hsieh; Meng-Hui Li; Kuo-Lun Tung

2008-01-01

79

Phenyl benzenesulfonamides are novel and selective 5-HT6 antagonists: identification of N-(2,5-dibromo-3-fluorophenyl)-4-methoxy-3-piperazin-1-ylbenzenesulfonamide (SB-357134).  

PubMed

Substituted N-phenyl-4-methoxy-3-piperazin-1-ylbenzenesulfonamides and conformationally restricted analogues have been identified as high affinity and selective 5-HT6 antagonists. Compounds from this series had a range of pharmacokinetic profiles in rat and in general there was a correlation between clearance and CNS penetration. Based on its overall biological profile 2 (SB-357134) was selected for further pre-clinical evaluation. PMID:11140733

Bromidge, S M; Clarke, S E; Gager, T; Griffith, K; Jeffrey, P; Jennings, A J; Joiner, G F; King, F D; Lovell, P J; Moss, S F; Newman, H; Riley, G; Rogers, D; Routledge, C; Serafinowska, H; Smith, D R

2001-01-01

80

Piperazine-2,3-dicarboxylic acid Derivatives as Dual Antagonists of NMDA and GluK1-Containing Kainate Receptors  

PubMed Central

Competitive N-methyl-D-aspartate receptor (NMDAR) antagonists bind to the GluN2 subunit, of which there are four types (GluN2A-D). We report that some N1-substituted derivatives of cis-piperazine-2,3-dicarboxylic acid display improved relative affinity for GluN2C and GluN2D versus GluN2A and GluN2B. These derivatives also display subtype-selectivity among the more distantly related kainate receptor family. Compounds 18i and (?)-4 were the most potent kainate receptor antagonists and 18i was selective for GluK1 versus GluK2, GluK3 and AMPA receptors. Modeling studies revealed structural features required for activity at GluK1 subunits and suggested that S674 was vital for antagonist activity. Consistent with this hypothesis, replacing the equivalent residue in GluK3 (alanine) with a serine imparts 18i antagonist activity. Antagonists with dual GluN2D and GluK1 antagonist activity may have beneficial effects in various neurological disorders. Consistent with this idea, antagonist 18i (30 mg/Kg i.p.) showed antinociceptive effects in an animal model of mild nerve injury. PMID:22111545

Irvine, Mark W.; Costa, Blaise M.; Dlaboga, Daniel; Culley, Georgia; Hulse, Richard; Scholefield, Caroline L.; Atlason, Palmi; Fang, Guangyu; Eaves, Richard; Morley, Richard; Mayo-Martin, Maria B.; Amici, Mascia; Bortolotto, Zuner A.; Donaldson, Lucy; Collingridge, Graham L.; Molnár, Elek; Monaghan, Daniel T.; Jane, David E.

2011-01-01

81

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine  

NASA Astrophysics Data System (ADS)

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n = 4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH = 3.05, 6.50, 8.40). The UV absorption and fluorescence intensity of NPP remarkably increased in presence of SCXn revealing formation of the inclusion complexes between NPP and SCXn. Moreover, the formation constants (K) of inclusion complexes were also determined by the non-linear fitting method, and the obtained data showed that the formation constants decreased gradually with the increasing of the pH value. When the pH value was 3.05, the formation constant of NPP with SCX8 reached a maximum of 1.7 × 107 L mol-1. The stoichiometric ratio was verified to be 1:1 by the continuous variation method. Meanwhile FT-IR and DSC analysis also indicated that NPP could form the inclusion complex with SCXn. In order to explore the inclusion mechanism of NPP with SCXn, 1H NMR and molecular modeling studies were carried out and experimental results showed that the part of benzene ring of NPP penetrated into the hydrophobic cavity of SCXn.

Zhang, Yongbin; Chao, Jianbin; Zhao, Shuhui; Xu, Penghao; Wang, Hongfang; Guo, Zhiqiang; Liu, Diansheng

2014-11-01

82

Growth, nonlinear optical, thermal, dielectric and laser damage threshold studies of semiorganic crystal: Monohydrate piperazine hydrogen phosphate  

NASA Astrophysics Data System (ADS)

Monohydrate piperazine hydrogen phosphate (MPHP), a semi organic nonlinear optical material has been synthesized and single crystals were grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction study on grown crystal reveals that they belong to monoclinic crystal system with space group P21/c; (a = 6.39 Å; b = 12.22 Å; c = 11.16 Å; ? = 97.14°; V = 864 Å3). The structural perfection of the grown crystal was analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. FTIR spectrum confirms the presence of the functional groups in synthesized material. UV-Vis spectrum indicates that the crystal is transparent in the entire visible region with a lower cut off wavelength of 387 nm. The variation of dielectric properties of the grown crystal with respect to frequency has been investigated at different temperatures. Thermal analysis carried out on the MPHP crystal shows that the crystal is stable up to 135 °C. Relative powder second harmonic generation efficiency tested by Kurtz-Perry powder technique, which was about 0.638 times that of Potassium dihydrogen phosphate.

Krishnan, P.; Gayathri, K.; Bhagavannarayana, G.; Gunasekaran, S.; Anbalagan, G.

2013-02-01

83

Solid-state variable-temperature NMR study of the phase separation of polybutadiene polyurethane zwitterionomers  

NASA Astrophysics Data System (ADS)

Polybutadiene polyurethane (PBDPU) zwitterionomers based on 4,4'-diphenylmethane diisocyanate (MDI), methyl-diethanolamine (MDEA), and hydroxy terminated polybutadiene are studied with variable-temperature (VT) wide-line 1H NMR. Spin—spin relaxation times ( T2) and spin—lattice relaxation times ( T1) are measured. It is found that phase separation of PBDPU does not change significantly upon ionization. The initial incorporation of ionization groups destroys the crystallinity of the hard segment while further ionization enhances physical crosslinks in the hard phase. The results are compared with a previous VT NMR study on polyether polyurethane zwitterionomers based on MDI, MDEA and 1000 Da molecular weight polytetramethylene oxide.

Yang, G.; Chen, Q.; Wang, Y.; Yang, C.; Wu, X.

1994-07-01

84

N-Aryl Piperazine Metabotropic Glutamate Receptor 5 Positive Allosteric Modulators Possess Efficacy in Preclinical Models of NMDA Hypofunction and Cognitive Enhancement  

PubMed Central

Impaired transmission through glutamatergic circuits has been postulated to play a role in the underlying pathophysiology of schizophrenia. Furthermore, inhibition of the N-methyl-d-aspartate (NMDA) subtype of ionotropic glutamate receptors (NMDAR) induces a syndrome that recapitulates many of the symptoms observed in patients with schizophrenia. Selective activation of metabotropic glutamate receptor subtype 5 (mGlu5) may provide a novel therapeutic approach for treatment of symptoms associated with schizophrenia through facilitation of transmission through central glutamatergic circuits. Here, we describe the characterization of two novel N-aryl piperazine mGlu5 positive allosteric modulators (PAMs): 2-(4-(2-(benzyloxy)acetyl)piperazin-1-yl)benzonitrile (VU0364289) and 1-(4-(2,4-difluorophenyl)piperazin-1-yl)-2-((4-fluorobenzyl)oxy)ethanone (DPFE). VU0364289 and DPFE induced robust leftward shifts in the glutamate concentration-response curves for Ca2+ mobilization and extracellular signal-regulated kinases 1 and 2 phosphorylation. Both PAMs displayed micromolar affinity for the common mGlu5 allosteric binding site and high selectivity for mGlu5. VU0364289 and DPFE possessed suitable pharmacokinetic properties for dosing in vivo and produced robust dose-related effects in reversing amphetamine-induced hyperlocomotion, a preclinical model predictive of antipsychotic-like activity. In addition, DPFE enhanced acquisition of contextual fear conditioning in rats and reversed behavioral deficits in a mouse model of NMDAR hypofunction. In contrast, DPFE had no effect on reversing apomorphine-induced disruptions of prepulse inhibition of the acoustic startle reflex. These mGlu5 PAMs also increased monoamine levels in the prefrontal cortex, enhanced performance in a hippocampal-mediated memory task, and elicited changes in electroencephalogram dynamics commensurate with procognitive effects. Collectively, these data support and extend the role for the development of novel mGlu5 PAMs for the treatment of psychosis and cognitive deficits observed in individuals with schizophrenia. PMID:23965381

Gregory, K.J.; Herman, E.J.; Ramsey, A.J.; Hammond, A.S.; Byun, N.E.; Stauffer, S.R.; Manka, J.T.; Jadhav, S.; Bridges, T.M.; Weaver, C.D.; Niswender, C.M.; Steckler, T.; Drinkenburg, W.H.; Ahnaou, A.; Lavreysen, H.; Macdonald, G.J.; Bartolome, J.M.; Mackie, C.; Hrupka, B.J.; Caron, M.G.; Daigle, T.L.; Lindsley, C.W.; Conn, P.J.

2013-01-01

85

Synthesis and biological evaluation of novel benzyl piperazine derivatives of 5-(5-nitroaryl)-1,3,4-thiadiazoles as Anti-Helicobacter pylori agents  

PubMed Central

Background and the purpose of the study Helicobacter pylori is recognized as the main cause of gastritis and gastroduodenal ulcers and classified as class 1 carcinogen pathogen. Different 1,3,4-thiadiazole derivatives bearing 5-nitroaryl moiety have been shown considerable anti- H. pylori activity. In attempt to find new and potent derivatives of described scaffold, a new series of 1-(substituted benzyl)-4-(5-(5-nitroaryl-2-yl)-1,3,4-thiadiazol-2-yl)piperazine derivatives were synthesized and evaluated against three metronidazole-resistant isolates of H. pylori using paper disk diffusion bioassay test. Methods The title compounds were prepared through the reaction of 1-(5-(5-nitroaryl-2-yl)-1,3,4-thiadiazol-2-yl) piperazine 5a-b and substituted benzyl chloride in DMF. The inhibitory activity of the new derivatives 6a-q against three metronidazole-resistant isolates of H. pylori was evaluated by the disc diffusion method and compared with the commercially available standard drug metronidazole. Results and discussion The results of SAR study indicated that the potency and anti-H. pylori activity profile of synthesized derivatives is mainly attributed to the substituted nitroaryl moiety at the C-5 position of 1,3,4-thiadiazole ring. Most of 1,3,4-thiadiazole derivatives bearing 5-nitrofuran moiety at C-5 position of central thiadiazole ring, demonstrated more promising anti-H. pylori than the 5-nitrothiophen counterpart. Conclusion The most potent nitrofuran derivative containing 3-methoxybenzyl piperazine pendant at the C-2 position of 1,3,4-thiadiazole ring (compound 6i), demonstrated strong anti-H. pylori potential at studied concentrations 100-25 ?g/disk (IZD?>?20 mm) against all studied metronidazole- resistant isolates of H. pylori. PMID:23924894

2013-01-01

86

New class of methyl tetrazole based hybrid of (Z)-5-benzylidene-2-(piperazin-1-yl)thiazol-4(%H)-one as potent antitubercular agents.  

PubMed

In search of potential therapeutics for tuberculosis, we describe here the synthesis and in vitro antitubercular activity of a novel series of thiazolone piperazine tetrazole derivatives. Among all the synthesized derivatives, four compounds (10, 14, 20 and 33) exhibited more potent activity (MIC=3.08, 3.01, 2.62 and 2.51 ?M) than ethambutol (MIC=9.78 ?M) and pyrazinamide (MIC=101.53 ?M) against Mycobacterium tuberculosis. Furthermore, they displayed no toxicity against Vero cells (C1008) and mouse bone marrow derived macrophages (MBMDM?). These investigated analogues have emerged as possible lead molecule to enlarge the scope of the study. PMID:25127167

Chauhan, Kuldeep; Sharma, Moni; Trivedi, Priyanka; Chaturvedi, Vinita; Chauhan, Prem M S

2014-09-01

87

Investigation of the mode of binding of a novel series of N-benzyl-4-heteroaryl-1-(phenylsulfonyl)piperazine-2-carboxamides to the hepatitis C virus polymerase  

SciTech Connect

Structure based rationales for the activities of potent N-benzyl-4-heteroaryl-1-(phenylsulfonyl)piperazine-2-carboxamide inhibitors of the hepatitis C viral polymerase are described herein. These compounds bind to the hepatitis C virus non-structural protein 5B (NS5B), and co-crystal structures of select examples from this series with NS5B are reported. Comparison of co-crystal structures of a potent analog with both NS5B genotype 1a and genotype 1b provides a possible explanation for the genotype-selectivity observed with this compound class and suggests opportunities for the further optimization of the series.

Gentles, Robert G.; Sheriff, Steven; Beno, Brett R.; Wan, Changhong; Kish, Kevin; Ding, Min; Zheng, Xiaofan; Chupak, Louis; Poss, Michael A.; Witmer, Mark R.; Morin, Paul; Wang, Ying-Kai; Rigat, Karen; Lemm, Julie; Voss, Stacey; Liu, Mengping; Pelosi, Lenore; Roberts, Susan B.; Gao, Min; Kadow, John F. (BMS) [BMS

2013-11-20

88

Mechanism-Based Inactivation of Human Cytochrome P450 3A4 by Two Piperazine-Containing Compounds.  

PubMed

Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine (EMTPP) have been previously identified as mechanism-based inactivators (MBI) of CYP2D6. The present study shows that both SCH 66712 and EMTPP are also MBIs of CYP3A4. Inhibition of CYP3A4 by SCH 66712 and EMTPP was determined to be concentration, time, and NADPH dependent. In addition, inactivation of CYP3A4 by SCH 66712 was shown to be unaffected by the presence of electrophile scavengers. SCH 66712 displays type I binding to CYP3A4 with a spectral binding constant (Ks) of 42.9 ± 2.9 µM. The partition ratios for SCH 66712 and EMTPP were 11 and 94, respectively. Whole protein mass spectrum analysis revealed 1:1 binding stoichiometry of SCH 66712 and EMTPP to CYP3A4 and a mass increase consistent with adduction by the inactivators without addition of oxygen. Heme adduction was not apparent. Multiple mono-oxygenation products with each inactivator were observed; no other products were apparent. These are the first MBIs to be shown to be potent inactivators of both CYP2D6 and CYP3A4. PMID:25273356

Bolles, Amanda K; Fujiwara, Rina; Briggs, Erran D; Nomeir, Amin A; Furge, Laura Lowe

2014-12-01

89

Measurement of nitrosamine and nitramine formation from NOx reactions with amines during amine-based carbon dioxide capture for postcombustion carbon sequestration.  

PubMed

With years of full-scale experience for precombustion CO(2) capture, amine-based technologies are emerging as the prime contender for postcombustion CO(2) capture. However, concerns for postcombustion applications have focused on the possible contamination of air or drinking water supplies downwind by potentially carcinogenic N-nitrosamines and N-nitramines released following their formation by NO(x) reactions with amines within the capture unit. Analytical methods for N-nitrosamines in drinking waters were adapted to measure specific N-nitrosamines and N-nitramines and total N-nitrosamines in solvent and washwater samples. The high levels of amines, aldehydes, and nitrite in these samples presented a risk for the artifactual formation of N-nitrosamines during sample storage or analysis. Application of a 30-fold molar excess of sulfamic acid to nitrite at pH 2 destroyed nitrite with no significant risk of artifactual nitrosation of amines. Analysis of aqueous morpholine solutions purged with different gas-phase NO and NO(2) concentrations indicated that N-nitrosamine formation generally exceeds N-nitramine formation. The total N-nitrosamine formation rate was at least an order of magnitude higher for the secondary amine piperazine (PZ) than for the primary amines 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA) and the tertiary amine methyldiethanolamine (MDEA). Analysis of pilot washwater samples indicated a 59 ?M total N-nitrosamine concentration for a system operated with a 25% AMP/15% PZ solvent, but only 0.73 ?M for a 35% MEA solvent. Unfortunately, a greater fraction of the total N-nitrosamine signal was uncharacterized for the MEA-associated washwater. At a 0.73 ?M total N-nitrosamine concentration, a ~25000-fold reduction in concentration is needed between washwater units and downwind drinking water supplies to meet proposed permit limits. PMID:22831707

Dai, Ning; Shah, Amisha D; Hu, Lanhua; Plewa, Michael J; McKague, Bruce; Mitch, William A

2012-09-01

90

Toward understanding amines and their degradation products from postcombustion CO2 capture processes with aerosol mass spectrometry.  

PubMed

Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

Ge, Xinlei; Shaw, Stephanie L; Zhang, Qi

2014-05-01

91

Process Design and Integration of Shale Gas to Methanol  

E-print Network

Noureldin for assistance with process design. 6 NOMENCLATURE C2 ? ethane C3 ? propane DEA ? diethanolamine GHG ? greenhouse gas kWh ? kilowatt hour LPG ? liquefied petroleum gas MDEA ? methyldiethanolamine MEA ? monoethanolamine Me... are separated into light and heavy fractions through cooling and partial condensation in a heat exchanger. Modern plants use cryogenic separation to separate propane and butane, also known as liquefied petroleum gas (LPG). In this process, crude gas...

Ehlinger, Victoria M.

2013-02-04

92

Simultaneous process and molecular design/selection through property integration  

E-print Network

CO2-Eq. Carbon dioxide equivalent d Characteristic value in Eq. (3.30) DEG Diethylene glycol DGA Diglycolamine E Emission F Process source flowrate f fresh source index fi,j flowrate of source i entering... gas treatment facility, two process sources diethylene glycol (DEG) (S1) and monoethanolamine (MEA) (S2) are used with a fresh stream of methyldiethanolamine (MDEA) (F1) to make up the solvent loss (Kohl and Nielsen, 1997). Operating experience...

Qin, Xiaoyun

2007-04-25

93

Synthesis of new 1-phenyl-2-(4-substituted-piperazin-1-yl)-propanol derivatives and evaluation of their antidepressant-like effects.  

PubMed

In this study, we synthesized eight novel 1-phenyl-2-(4-substituted-piperazin-1-yl)-propanol derivatives and evaluated their antidepressant-like activities. The chemical structures of the synthesised compounds were elucidated by spectroscopy and elemental analyses. Potential antidepressant-like effects of the test compounds (20 mg kg(-1)) were investigated using the tail-suspension test and modified forced swimming test (MFST) in mice. Additionally, the spontaneous locomotor activity of the mice was assessed using the activity cage apparatus. Both the reference drug fluoxetine (20 mg kg(-1)) and the test compounds 3a-3e and 3g significantly shortened the immobility time of the mice in both the behavioural tests. These test compounds also increased the swimming time in MFST without any change in the climbing duration. Compounds 3c-3e and 3g were significantly more potent in inducing these effects than 3a and 3b. None of the compounds changed the locomotor activities of the animals, thus antidepressant-like effects of test compounds were specific. The findings support those of previous studies that reported antidepressant-like activities of aryl alkanol piperazine derivatives. PMID:23595553

Demir Özkay, Ümide; Yurtta?, Leyla; Özkay, Yusuf; Üçel, Umut Irfan; Can, Özgür Devrim; Öztürk, Yusuf

2013-07-01

94

Lanthanide N,N'-piperazine-bis(methylenephosphonates) (Ln=La, Ce, Nd) that display flexible frameworks, reversible hydration and cation exchange  

SciTech Connect

Hydrothermal syntheses of lanthanide bisphosphonate metal organic frameworks comprising the light lanthanides lanthanum, cerium and neodymium and N,N'-piperazine bis(methylenephosphonic acid) (H{sub 2}L(1) and its 2-methyl and 2,5-dimethyl derivatives (H{sub 2}L(2) and H{sub 2}L(3)) gives three new structure types. At elevated starting pH (ca. 5 and above) syntheses give 'type I' materials with all metals and acids of the study (MLnLxH{sub 2}O, M=Na, K, Cs; Ln=La, Ce, Nd; x{approx}4: KCeL(1).4H{sub 2}O, C2/c, a=23.5864(2) A, b=12.1186(2) A, c=5.6613(2) A, beta=93.040(2){sup o}). The framework of structure type I shows considerable flexibility as the ligand is changed, due mainly to rotation around the -N-CH{sub 2}- bond of the linker in response to steric considerations. Type I materials demonstrate cation exchange and dehydration and rehydration behaviour. Upon dehydration of KCeL.4H{sub 2}O, the space group changes to P2{sub 1}/n, a=21.8361(12) A, b=9.3519(4) A, c=5.5629(3) A, beta=96.560(4){sup o}, as a result of a change of the piperazine ring from chair to boat configuration. When syntheses are performed at lower pH, two other structure types crystallise. With the 'non-methyl' ligand 1, type II materials result (LnL(1)H{sub 2}L(1).4.5H{sub 2}O: Ln=La, P-1, a=5.7630(13) A, b=10.213(2) A, c=11.649(2) A, alpha=84.242(2){sup o}, beta=89.051(2){sup o}, gamma=82.876(2){sup o}) in which one half of the ligands coordinate via the piperazine nitrogen atoms. With the 2-methyl ligand, structure type III crystallises (LnHL(2).4H{sub 2}O: Ln=Nd, Ce, P2{sub 1}/c, a=5.7540(9) A, b=14.1259(18) A, c=21.156(5) A, beta=90.14(2){sup o}) due to unfavourable steric interactions of the methyl group in structure type II. - Graphical abstract: The lanthanides La, Ce and Nd give a family of metal organic frameworks based on N,N'-piperazinebismethylenephosphonate ligands: these display reversible dehydration, structural flexibility and cation exchange.

Mowat, John P.S.; Groves, John A.; Wharmby, Michael T.; Miller, Stuart R.; Li Yang; Lightfoot, Philip [School of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife KY16 9ST (United Kingdom); Wright, Paul A., E-mail: paw2@st-and.ac.u [School of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife KY16 9ST (United Kingdom)

2009-10-15

95

Poly[bis-[8-ethyl-5-oxo-2-(piperazin-1-yl)-5,8-dihydro-pyrido[2,3-d]pyrimidine-6-carboxyl-ato]cadmium  

PubMed Central

The title layered coordination polymer, [Cd(C14H16N5O3)2]n or [Cd(ppa)2]n, where ppa is 8-ethyl-5-oxo-2-(piperazin-1-yl)-5,8-dihydro­pyrido[2,3-d]pyrimidine-6-carboxyl­ate, was syn­thesized under hydro­thermal conditions. The CdII atom (site symmetry 2) exhibits a distorted cis-CdN2O4 octa­hedral geometry defined by two N-monodentate and two O,O?-bidentate ppa monoanions. The extended two-dimensional structure resulting from the bridging ppa species is a grid lying parallel to (001). An N—H?O hydrogen bond helps to establish the crystal packing. PMID:21588905

Gao, Jun; Gao, Jing; Pei, Bo; Huang, Jing

2010-01-01

96

Novel 3-nitro-1H-1,2,4-triazole-based piperazines and 2-amino-1,3-benzothiazoles as antichagasic agents  

PubMed Central

We have previously shown that 3-nitro-1H-1,2,4-triazole-based amines demonstrate significant trypanocidal activity, in particular against T. cruzi, the causative parasite of Chagas disease. In the present work we further expanded our research by evaluating in vitro the trypanocidal activity of nitrotriazole-based piperazines and nitrotriazole-based 2-amino-1,3-benzothiazoles to establish additional SARs. All nitrotriazole-based derivatives were active or moderately active against T. cruzi; however two of them did not fulfill the selectivity criteria. Five derivatives were active or moderately active against T.b. rhodesiense while one derivative was moderately active against L. donovani. Active compounds against T. cruzi demonstrated selectivity indexes (toxicity to host cells/toxicity to T. cruzi amastigotes) from 117-1725 and 12 of 13 compounds were up to 39-fold more potent than the reference compound benznidazole. Detailed SARs are discussed. PMID:24012457

Papadopoulou, Maria V.; Bloomer, William D.; Rosenzweig, Howard S.; Kaiser, Marcel; Chatelain, Eric; Ioset, Jean-Robert

2013-01-01

97

Synthesis and evaluation of 4-substituted piperidines and piperazines as balanced affinity ? opioid receptor (MOR) agonist/? opioid receptor (DOR) antagonist ligands.  

PubMed

In this letter, we describe a series of 4-substituted piperidine and piperazine compounds based on tetrahydroquinoline 1, a compound that shows balanced, low nanomolar binding affinity for the mu opioid receptor (MOR) and the delta opioid receptor (DOR). We have shown that by changing the length and flexibility profile of the side chain in this position, binding affinity is improved at both receptors by a significant degree. Furthermore, several of the compounds described herein display good efficacy at MOR, while simultaneously displaying DOR antagonism. The MOR agonist/DOR antagonist has shown promise in the reduction of negative side effects displayed by selective MOR agonists, namely the development of dependence and tolerance. PMID:24365161

Bender, Aaron M; Clark, Mary J; Agius, Michael P; Traynor, John R; Mosberg, Henry I

2014-01-15

98

catena-Poly[[[tetra-aqua-magnesium]-trans-?-[(piperazine-1,4-diium-1,4-di-yl)bis-(methyl-ene)]di-phospho-nato] hemihydrate  

PubMed Central

The structure of the title polymer, }[Mg(C6H14N2O6P2)(H2O)4]·0.5H2O}n, is based on centrosymmetric MgO6 octahedra, which are linked by [(piperazine-1,4-diium-1,4-di­yl)bis­(methyl­ene)]di­phospho­nate ligands, forming chains parallel to [1-1-1]. These chains are connected via hydrogen bonds primarily formed between the phospho­nate groups and water mol­ecules. The latter constitute four of the corners of the MgO6 polyhedra and bind to the O atoms of the phospho­nate groups of neighbouring chains. The lattice water molecule is disordered around an inversion centre, exhibiting an occupancy of 0.25. PMID:24109276

Schilling, Lars-Hendrik; Stock, Norbert

2013-01-01

99

Piperidin-1-yl-phosphonic acid and (4-phosphono-piperazin-1-yl) phosphonic acid: A new class of iron corrosion inhibitors in sodium chloride 3% media  

NASA Astrophysics Data System (ADS)

The inhibiting effect of the piperidin-1-yl-phosphonic acid (PPA) and (4-phosphono-piperazin-1-yl) phosphonic acid (PPPA) on the behavior of iron in 3% NaCl media has been examined by electrochemical and gravimetric measurements. Potentiodynamic polarization studies clearly reveal the fact that the addition of increasing concentrations of phosphonic acids moves the corrosion potential towards negative values and reduces the corrosion rate. In uninhibited and inhibited solutions, the increasing of temperature reduces the inhibition efficiency. Changes in impedance parameters ( Rt and Cdl) are indicative of adsorption of PPA and PPPA on the metal surface leading to the formation of protective films. Gravimetric measurements reveal that the presence of PPA and PPPA increases the inhibition efficiency by decreasing the corrosion rate. The results obtained by corrosion weight loss tests reveal that adsorption of compounds tested on the ARMCO iron surface obeys to Langmuir adsorption isotherm.

Amar, H.; Benzakour, J.; Derja, A.; Villemin, D.; Moreau, B.; Braisaz, T.

2006-07-01

100

Critical tests in equids with fenbendazole alone or combined with piperazine: particular reference to activity on benzimidazole-resistant small strongyles.  

PubMed

Seven critical tests in equids were conducted with single doses of fenbendazole (5 mg kg-1) alone (Panacur--American Hoechst, Somerville, NJ); (2 tests with paste and 1 with suspension formulation) or in combination with piperazine (American Hoechst); (40 mg base kg-1); (4 tests with paste formulation). The main purpose of the tests was evaluation of activity against benzimidazole-resistant small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus). Natural infections of 2 populations of benzimidazole-resistant small strongyles were evaluated; 1 was population B in 2 horses and the other was population S in 5 ponies. Removal of the 5 species of population B was 49-91% in the animal treated with fenbendazole paste alone and 100% (4 of these species present) in the animal treated with the combination. For population S, 2 of the 5 resistant species were present in small numbers in 1 animal treated with fenbendazole paste alone and all were removed; the 1 animal receiving fenbendazole suspension alone had removals of 0-70% for the 5 benzimidazole-resistant species. Also for population S, the 5 resistant species were present in 2 animals treated with the paste combination and removal was 98-100% and of 4 of the 5 resistant species in 1 animal, removal was 76-99%. Removal of large strongyles (Strongylus vulgaris and Strongylus edentatus) was 92-100% for fenbendazole paste alone or in combination with piperazine in the 5 infected animals. For Oxyuris equi, present in 1 animal treated with the combination, there was 91% removal of immature and 100% removal of mature specimens. There probHably was no activity by fenbendazole alone or the combination against bots, tapeworms, and parenteral stages of S. vulgaris and S. edentatus. The combination may have had some activity against immature Habronema spp. and mature abronema muscae. PMID:6683041

Lyons, E T; Tolliver, S C; Drudge, J H

1983-02-01

101

Development of simultaneous gas chromatography–mass spectrometric and liquid chromatography–electrospray ionization mass spectrometric determination method for the new designer drugs, N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP) and their main metabolites in urine  

Microsoft Academic Search

To prove the intake of recently controlled designer drugs, N-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP), a simple, sensitive and reliable method which allows us to simultaneously detect BZP, TFMPP and their major metabolite in human urine has been established by coupling gas chromatography–mass spectrometry (GC–MS) and high-performance liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS). GC–MS accompanied by trifluoroacetyl (TFA) derivatization and LC–MS

Hiroe Tsutsumi; Munehiro Katagi; Akihiro Miki; Noriaki Shima; Tooru Kamata; Mayumi Nishikawa; Kunio Nakajima; Hitoshi Tsuchihashi

2005-01-01

102

catena-Poly[[[(1-ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydro-quinoline-3-carboxyl-ato-?2 O 3,O 4)copper(II)]-?-1-ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydro-quinoline-3-carboxyl-ato-?3 N 7?:O 3,O 4] tetra-hydrate  

PubMed Central

In the title compound, {[Cu(C16H17FN3O3)2]·4H2O}n, the CuII atom is bonded to two O,O?-bidentate 1-ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydro­quinoline-3-carboxyl­ate (norf) monoanions and a symmetry-generated N-bonded norf anion, resulting in a distorted square-pyramidal coordination environ­ment with the N atom occupying the apical site. The bridging norf anion results in one-dimensional chains propogating along [010]. A network of O—H?O and N—H?O hydrogen bonds helps to establish the crystal structure. PMID:21201639

Wang, Shu-Ye; Song, Xue-Ming; Duan, Li-Xiang; An, Zhe

2008-01-01

103

Mononuclear zinc(II) complexes of 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols: Synthesis, structural characterization, DNA binding and cheminuclease activities  

NASA Astrophysics Data System (ADS)

Four new zinc(II) complexes [Zn(HL1-4)Cl2] (1-4), where HL1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, have been isolated and fully characterized using various spectro-analytical techniques. The X-ray crystal structure of complex 4 shows the distorted trigonal-bipyramidal coordination geometry around zinc(II) ion. The crystal packing is stabilized by intermolecular NH⋯O hydrogen bonding interaction. The complexes display no d-d electronic band in the visible region due to d10 electronic configuration of zinc(II) ion. The electrochemical properties of the synthesized ligands and their complexes exhibit similar voltammogram at reduction potential due to electrochemically innocent Zn(II) ion, which evidenced that the electron transfer is due to the nature of the ligand. Binding interaction of complexes with calf thymus DNA was studied by UV-Vis absorption titration, viscometric titration and cyclic voltammetry. All complexes bind with CT DNA by intercalation, giving the binding affinity in the order of 2 > 1 ? 3 > 4. The prominent cheminuclease activity of complexes on plasmid DNA (pBR322 DNA) was observed in the absence and presence of H2O2. Oxidative pathway reveals that the underlying mechanism involves hydroxyl radical.

Ravichandran, J.; Gurumoorthy, P.; Karthick, C.; Kalilur Rahiman, A.

2014-03-01

104

Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines  

NASA Astrophysics Data System (ADS)

A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2?-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

2014-12-01

105

Synthesis, growth, structural and optical studies of organic nonlinear optical material - Piperazine-1,4-diium bis 2,4,6-trinitrophenolate  

NASA Astrophysics Data System (ADS)

Piperazine-1,4-diium bis 2,4,6-trinitrophenolate is one of the useful organic materials with nonlinear optical (NLO) and pharmaceutical applications. The material was grown by slow evaporation solution growth method at room temperature. The crystal system and lattice parameters were identified by single crystal XRD analysis. The grown material crystallizes in monoclinic system with P21/n space group. The main functional groups NH2, NO2, Csbnd N, Cdbnd C, and phenolic ‘O' atom were identified using FTIR analysis. The protons and carbons of grown crystal with various chemical environments were studied by 1H and 13C NMR spectroscopy to confirm the molecular structure. The optical properties of the crystal were studied by UV-vis-NIR spectroscopy and the transmission 100% range starts from 532 nm onwards. The optical band gap was measured as 2.63 eV from the plot of (?h?)2 versus h?. The thermal stability was detected at 304.1 °C using TG-DTA analysis. The dielectric studies of the sample were carried out at different temperatures in the frequency range from 50 Hz to 5 MHz to establish the dielectric nature of the crystal. Photoconductivity measurements were carried out on the grown crystal. The Second Harmonic Generation (SHG) of the crystal was tested to confirm the nonlinear optical property.

Suguna, S.; Anbuselvi, D.; Jayaraman, D.; Nagaraja, K. S.; Jeyaraj, B.

2014-11-01

106

Synthesis, growth, structural and optical studies of organic nonlinear optical material--piperazine-1,4-diium bis 2,4,6-trinitrophenolate.  

PubMed

Piperazine-1,4-diium bis 2,4,6-trinitrophenolate is one of the useful organic materials with nonlinear optical (NLO) and pharmaceutical applications. The material was grown by slow evaporation solution growth method at room temperature. The crystal system and lattice parameters were identified by single crystal XRD analysis. The grown material crystallizes in monoclinic system with P21/n space group. The main functional groups NH2, NO2, CN, CC, and phenolic 'O' atom were identified using FTIR analysis. The protons and carbons of grown crystal with various chemical environments were studied by 1H and 13C NMR spectroscopy to confirm the molecular structure. The optical properties of the crystal were studied by UV-vis-NIR spectroscopy and the transmission 100% range starts from 532 nm onwards. The optical band gap was measured as 2.63 eV from the plot of (?h?)2 versus h?. The thermal stability was detected at 304.1°C using TG-DTA analysis. The dielectric studies of the sample were carried out at different temperatures in the frequency range from 50 Hz to 5 MHz to establish the dielectric nature of the crystal. Photoconductivity measurements were carried out on the grown crystal. The Second Harmonic Generation (SHG) of the crystal was tested to confirm the nonlinear optical property. PMID:24878440

Suguna, S; Anbuselvi, D; Jayaraman, D; Nagaraja, K S; Jeyaraj, B

2014-11-11

107

Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines.  

PubMed

A series of heteroleptic copper(II) complexes of the type [CuL(1-4)(diimine)](ClO4)2 (1-8) [L(1-4)=2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine=2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172×10(-)(4)cm(-)(1)) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in [Formula: see text] ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA. PMID:24998685

Ravichandran, J; Gurumoorthy, P; Imran Musthafa, M A; Kalilur Rahiman, A

2014-12-10

108

Optically active antifungal azoles: synthesis and antifungal activity of (2 R,3 S)-2-(2,4-difluorophenyl)-3-(5-{2-[4-aryl-piperazin-1-yl]-ethyl}-tetrazol-2-yl\\/1-yl)-1-[1,2,4]-triazol-1-yl-butan-2-ol  

Microsoft Academic Search

A series of (2R,3S)-2-(2,4-difluorophenyl)-3-(5-{2-[4-aryl-piperazin-1-yl]-ethyl}-tetrazol-2-yl)-1-[1,2,4]-triazol-1-yl-butan-2-ol (11a–n) and (2R,3S)-2-(2,4-difluorophenyl)-3-(5-{2-[4-aryl-piperazin-1-yl]-ethyl}-tetrazole-1-yl)-1-[1,2,4]-triazol-1-yl-butan-2-ol (12a–n) has been synthesized. The antifungal activity of compounds was evaluated by in vitro agar diffusion and broth dilution assay. Compounds 11d and its positional isomer 12d having 3-trifluoromethyl substitution on the phenyl ring of piperazine demonstrated significant antifungal activity against variety of fungal cultures (Candida spp. C. neoformans and Aspergillus spp.). The

Ram Shankar Upadhayaya; Neelima Sinha; Sanjay Jain; Nawal Kishore; Ramesh Chandra; Sudershan K. Arora

2004-01-01

109

2-{2-[4-(4-Fluoro-phen-yl)piperazin-1-yl]-2-oxoeth-yl}-6-(morpholin-4-yl)-4-phenyl-pyridazin-3(2H)-one  

PubMed Central

In the title compound, C26H28FN5O3, the morpholine ring adopts a chair conformation. The piperazine ring is puckered [Q T = 0.5437?(15)?Å, ? = 8.89?(15) and ? = 357.2?(11)°]. The 1,6-dihydro­pyridazine ring makes dihedral angles of 28.03?(7) and 77.46?(7)° with the phenyl and benzene rings, respectively. In the crystal, mol­ecules are linked along the c axis by C—H?O inter­actions and are flattened parallel to the ac plane. C–H?? inter­actions also contribute to the stability of the structure. PMID:21522416

Ayd?n, Abdullah; Sukuroglu, Murat; Akkurt, Mehmet; Buyukgungor, Orhan

2011-01-01

110

Carbon dioxide adsorption by physisorption and chemisorption interactions in piperazine-grafted Ni2(dobdc) (dobdc = 1,4-dioxido-2,5-benzenedicarboxylate).  

PubMed

The metal-organic framework Ni(2)(dobdc) (CPO-27-Ni, where dobdc = 1,4-dioxido-2,5-benzenedicarboxylate) has been post-synthetically modified with piperazine (pip) - a known 'accelerator' to improve the kinetics of CO(2) uptake in alkanolamine solvents for chemical absorption - and the impact of the modification on the CO(2) uptake and selectivity over N(2) has been probed. While the modified framework, Ni(2)(dobdc)(pip)(0.5) (pip-CPO-27-Ni), exhibits a lower uptake of CO(2) compared with the non-grafted material, the selectivity for CO(2) over N(2) at 25 °C and at pressures pertinent to post-combustion flue gas capture (0.1-0.15 bar) is enhanced. Mechanistically, the interaction between the CO(2) molecules and the free amine sites in pip-CPO-27-Ni occurs via physisorption and chemisorption interactions, in which CO(2) binds to the framework with an isosteric heat of adsorption (-Q(st)) of 40.5 kJ mol(-1) at very low coverage (P = 0.033 mbar), followed by binding at a higher heat of adsorption (-Q(st) = 46.2 kJ mol(-1) at P = 3.55 mbar). Pure water adsorption isotherms revealed a two-step mechanism for uptake in CPO-27-Ni, consistent with adsorption into the first and second hydration spheres of Ni(2+) followed by subsequent uptake via physisorption into the pores. Additional steric hindrance in pip-CPO-27-Ni results in a single step only. The working capacity over multiple cycles was also investigated using a temperature swing adsorption process which revealed reversible CO(2) adsorption and desorption of 10 wt% over 10 cycles. PMID:22903310

Das, Anita; Southon, Peter D; Zhao, Ming; Kepert, Cameron J; Harris, Andrew T; D'Alessandro, Deanna M

2012-10-14

111

H-bond pattern in arylpiperazine structures. Structures of cis and trans 2-{4-[4-(2-methoxyphenyl)piperazin-1-yl]but-2-enyl}isoindoline-1,3-diones and their hydrochloride salts  

NASA Astrophysics Data System (ADS)

The crystal structures of cis and trans-isomers of 2-{4-[4-(2-methoxyphenyl)piperazin-1-yl]but-2-enyl}isoindoline-1,3-diones have been solved in two different forms - as free bases and as hydrochlorides. It was concluded that the conformations of arylpiperazine derivatives with an aliphatic spacer in their neutral and protonated forms are similar and usually extended. The molecule bending found for the free cis-isomer is reflected in variation of the supramolecular synthons formation. The hydrogen bonds pattern in studied structure was analyzed. In the crystals of both free bases head-to-head dimers are predominant, while in hydrochlorides inter-ionic salt bridges form the main structure motifs. The most important difference in hydrogen bonds patterns of both forms lies in the fact that piperazine carbon atoms contribute to weak C dbnd O···H-C interactions as proton donors only in the structures of hydrochlorides. This article will also review selected arylpiperazine structures deposited in CSD from the point of view of their hydrogen bonds pattern.

Karolak-Wojciechowska, Janina; Mrozek, Agnieszka; Fruzi?ski, Andrzej; Szczesio, Ma?gorzata; Kowalski, Piotr; Kowalska, Teresa

2010-08-01

112

Two new three-dimensional zinc phosphites templated by piperazine: [H2pip][Zn3(HPO3)4(H2O)2] and K[H2pip]0.5[Zn3(HPO3)4  

NASA Astrophysics Data System (ADS)

Two three-dimensional open-framework zinc phosphites with the same organically templated, [H2pip][Zn3(HPO3)4(H2O)2] (1) and K[H2pip]0.5[Zn3(HPO3)4] (2) (pip = piperazine), have been solvothermally synthesized and structurally characterized by IR, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Compound 1 consists of ZnO4 tetrahedra, [HPO3] pseudopyramids and [ZnO4(H2O)2] octahedra, which are linked through their vertexes to generate three-dimensional architecture with intersecting 8-membered channels along the [1 0 0], [0 0 1] and [1 0 1] directions. Compound 2 is constructed from strictly alternating ZnO4 tetrahedra and [HPO3] pseudopyramids, and exhibits (3,4)-connected inorganic framework with 8-, and 12-membered channels, in which the K+ and diprotonated H2pip2+ extra-framework cations reside, respectively. The coexistence of inorganic K+ and organic piperazine mixed templates in the structure is unique and, to the best of our knowledge, firstly observed in metal-phosphite materials. In addition, the participation of left-handed and right-handed helical chains in construction of the puckered 4.82 sheet structure in 2 is also noteworthy.

Zhang, Xiao; Wang, Guo-Ming; Wang, Zong-Hua; Wang, Ying-Xia; Lin, Jian-Hua

2014-01-01

113

Design, synthesis, radiolabeling and in vivo evaluation of carbon-11 labeled N-[2-[4-(3-cyanopyridin-2-yl)piperazin-1-yl]ethyl]-3-methoxybenzamide, a potential Positron Emission Tomography tracer for the dopamine D4 receptors  

PubMed Central

Here we describe the design, synthesis, physicochemical, and pharmacological evaluation of D4 dopamine receptor ligands related to N-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]-3-methoxybenzamide (2). Structural features were incorporated to increase affinity for the target receptor, to improve selectivity over D2 and sigma1 receptors, to enable labeling with carbon-11 or fluorine-18, and to adjust lipophilicity within the range considered optimal for brain penetration and low nonspecific binding. Compounds 7 and 13 showed the overall best characteristics: nanomolar affinity for the D4 receptor, > 100-fold selectivity over D2 and D3 dopamine receptor 5-HT1A, 5-HT2A and 5-HT2C serotonin receptors and sigma1 receptors, and logP = 2.37–2.55. Following intraperitoneal administration, both compounds rapidly entered the central nervous system. The methoxy of N-[2-[4-(3-cyanopyridin-2-yl)piperazin-1-yl]ethyl]-3-methoxybenzamide (7) was radiolabelled with carbon-11 and subjected to PET analysis in non-human primate. [11C]7 time-dependently accumulated to saturation in the posterior eye in the region of the retina, a tissue containing a high density of D4 receptors. PMID:20873719

Lacivita, Enza; De Giorgio, Paola; Lee, Irene T.; Rodeheaver, Sean I.; Weiss, Bryan A.; Fracasso, Claudia; Caccia, Silvio; Berardi, Francesco; Perrone, Roberto; Zhang, Ming-Rong; Maeda, Jun; Higuchi, Makoto; Suhara, Tetsuya; Schetz, John A.; Leopoldo, Marcello

2010-01-01

114

Shell coal gasification plant (SCGP-1) environmental performance results  

SciTech Connect

Environmental studies in slip-stream process development units at SCGP-1, Shell's advanced coal gasification demonstration plant, located near Houston, Texas, have demonstrated that the gas and water effluents from the Shell Coal Gasification Process (SCGP) are environmentally benign on a broad slate of coals. This report presents the results of those environmental studies. It contains two major subjects, which describe, respectively, the experiments on gas treating and the experiments on water treating. Gas treatment focused on the performance of aqueous methyldiethanolamine (MDEA) and sulfinol-M. 8 refs., 24 figs., 13 tabs.

Bush, W.V.; Baker, D.C.; Tijm, P.J.A. (Shell Development Co., Houston, TX (United States))

1991-07-01

115

Study of a regenerative process for selective sulfur dioxide removal using organic solvents  

SciTech Connect

In searching appropriate solvents for selective sulfur dioxide removal it has been found that sulfur dioxide solubility can be well correlated by the Gutmann donor number of the solvent. Two solvents, N-methylpyrrolidone (NMP) and methyldiethanolamine (MDEA), have been selected for experiments. Mixtures of sulfur dioxide and solvent (1:1 mole ratio) have been prepared at low temperature. These mixtures give complexes, stable under the experimental conditions, with a melting point well above the melting point of the separate components. These mixtures have been analyzed by infra red, ultraviolet/visible and nuclear magnetic resonance spectroscopy. Solubility of sulfur dioxide in NMP and MDEA has been measured at 25{degrees}C in the range of 2000-5000 ppmv using a stirred tank reactor. 14 refs., 4 figs., 2 tabs.

Van Dam, M.H.H.; Lamine, A.S. [Laboratorie des Sciences du Genie Chimiques (France)] [and others

1996-12-31

116

Designer Drug (DD) abuse in Poland; a review of the psychoactive and toxic properties of substances found from seizures of illegal drug products and the legal consequences thereof. Part II--piperazines/piperidines, phenylethylamines, tryptamines and miscellaneous 'others'.  

PubMed

As the second and concluding part, this paper continues the summary review of the scientific evidence obtained from the literature and focuses on the remaining 4/6 groupings of DDs identified in illegal products found in the huge drug seizures made recently in Poland. They consist of piperazines/piperidines, phenylethylamines, tryptamines, (briefly mentioned), and a miscellaneous 'others' category; cannabinoids and cathinones derivatives having being reviewed in the first part. Also included in the introduction and discussion sections, in both reviews, are some legal aspects variously interwoven with the science. It is thus intended that these two articles may help suitable legislation to be rapidly devised to make the prohibition of DDs permanent whenever deemed necessary, as well as providing an up-to-date reference source for those engaged in the DD issue; whether scientists or regulatory bodies. PMID:23311821

Bili?ski, Przemys?aw; Ho?ownia, Piotr; Kapka-Skrzypczak, Lucyna; Wojty?a, Andrzej

2012-01-01

117

Metabolism, excretion, and pharmacokinetics of ((3,3-difluoropyrrolidin-1-yl)((2S,4S)-4-(4-(pyrimidin-2-yl)piperazin-1-yl)pyrrolidin-2-yl)methanone, a dipeptidyl peptidase inhibitor, in rat, dog and human.  

PubMed

The disposition of 3,3-difluoropyrrolidin-1-yl{(2S,4S)-4-[4-(pyrimidin-2-yl)piperazin-1-yl]pyrrolidin-2-yl}methanone (PF-00734200), a dipeptidyl peptidase IV inhibitor that progressed to phase 3 for the treatment of type 2 diabetes, was examined in rats, dogs, and humans after oral administration of a single dose of [(14)C]PF-00734200. Mean recoveries of administered radioactivity were 97.1, 92.2, and 87.2% in rats, dogs, and humans, respectively. The majority of radioactive dose was detected in the urine of dogs and humans and in the feces of rats. Absorption of PF-00734200 was rapid in all species, with maximal plasma concentrations of radioactivity achieved within 1 h after the dose. Circulating radioactivity was primarily composed of the parent drug (79.9, 80.2, and 94.4% in rat, dog, and human, respectively). The major route of metabolism was due to hydroxylation at the 5' position of the pyrimidine ring (M5) in all species. In vitro experiments with recombinant cytochrome P450 isoforms suggested that the formation of M5 was catalyzed both by CYP2D6 and CYP3A4. Molecular docking simulations showed that the 5' position of the pyrimidine moiety of PF-00734200 can access the heme iron-oxo of both CYP3A4 and CYP2D6 in an energetically favored orientation. Other metabolic pathways included amide hydrolysis (M2), N-dealkylation at the piperazine nitrogen (M3) and an unusual metabolite resulting from scission of the pyrimidine ring (M1). Phase II metabolic pathways included the following: carbamoyl glucuronidation (M9), glucosidation (M15) on the pyrrolidine nitrogen, and conjugation with creatinine to form an unusual metabolite/metabonate (M16). The data from these studies suggest that PF-00734200 is eliminated by both metabolism and renal clearance. PMID:22896728

Sharma, Raman; Sun, Hao; Piotrowski, David W; Ryder, Tim F; Doran, Shawn D; Dai, Haiqing; Prakash, Chandra

2012-11-01

118

An azide-bridged copper(II) complex: poly[piperazine-1,4-dium [tetra-?3-azido-?(12)N(1):N(1):N(1)-hexa-?2-azido-?(12)N(1):N(1)-di-?2-azido-?(4)N(1):N(3)-pentacopper(II)] tetrahydrate].  

PubMed

A new Cu(II)-azide complex, {(C4H12N2)[Cu5(N3)12]·4H2O}n, has been synthesized by the reaction of piperazine, Cu(OAc)2·2H2O (OAc is acetate) and NaN3. In the structure, ?2-1,1- and ?3-1,1,1-azide anions bridge five Cu(II) cations to form a linear pentanuclear cluster unit, which is further linked by ?2-1,1- and ?2-1,3-azide anions to form a two-dimensional condensed [Cu5(N3)12]n layer. The diprotonated piperazine and the solvent water molecules are hydrogen bonded to the coordination layers to form a three-dimensional supramolecular network. PMID:25370112

Liu, Hou Ting; Lu, Jing

2014-11-15

119

Structural and spectroscopic characterization of a novel potential chemotherapeutic agent 3-(1-adamantyl)-1-{[4-(2-methoxyphenyl)piperazin-1-yl]methyl}-4-methyl-1H-1,2,4-triazole-5(4H)-thione by first principle calculations  

NASA Astrophysics Data System (ADS)

Quantum chemical calculations of energy, geometrical structure and vibrational wavenumbers of a novel functionalized triazoline-3-thione compound (a potential chemotherapeutic agent) with substituted piperazine and adamantyl substituents attached at the 2- and 5-positions, respectively, chemically known as 3-(1-adamantyl)-1-{[4-(2-methoxyphenyl)piperazin-1-yl]methyl}-4-methyl-1H-1,2,4-triazole-5(4H)-thione, were carried out, using DFT method. The detailed interpretation of the infrared and Raman spectra of the molecule under study is based on potential energy distribution. The difference between the observed and scaled wavenumbers of most of the normal modes is very small with B3LYP/6-311+G(d,p) method. The values of the electric dipole moment, polarizability and first static hyperpolarizability of the title compound have also been investigated. The HOMO, LUMO and molecular electrostatic potential map have been used to elucidate the molecular properties.

El-Emam, Ali A.; Al-Tamimi, Abdul-Malek S.; Al-Rashood, Khalid A.; Misra, Hriday N.; Narayan, Vijay; Prasad, Onkar; Sinha, Leena

2012-08-01

120

A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium  

NASA Astrophysics Data System (ADS)

Piperazine-dithiocarbamate of potassium (K2DTC2pz) was used as a new precursor for the spontaneous deposition of sulfur on the Au(100) surface in alkaline solution. Two new sulfur phases were studied by scanning tunneling microscopy (STM). These phases were formed by six sulfur atoms (S6 phase, hexamer) and by four sulfur atoms (S4 phase, tetramer with ?{2}×?{2} structure), and they were observed in coexistence with the well-known quasi-square patterns formed by eight sulfur atoms (S8 phase, octomer). A model was proposed where sulfur multilayers were formed by a ?{2}×?{2} phase adsorbed directly on the gold surface while one of the other structures: hexamers or octomers were deposited on top. Sulfur layers were formed on gold terraces, vacancies and islands produced by lifting reconstructed surface. Sequential high-resolution STM images allowed the direct observation of the dynamic of the octomers, while the ?{2}×?{2} structure remained static. Images also showed the reversible association/dissociation of the octomer.

Martínez, Javier A.; Valenzuela B., José; Cao Milán, R.; Herrera, José; Farías, Mario H.; Hernández, Mayra P.

2014-11-01

121

N-(3-Fluoro-4-(4-(2-methoxy or 2,3-dichlorophenyl) piperazine-1-yl)-butyl)-aryl carboxamides as Selective Dopamine D3 Receptor Ligands: Critical Role of the Carboxamide Linker for D3 Receptor Selectivity  

PubMed Central

N-(3-fluoro-4-(4-(2,3-dichloro- or 2-methoxyphenyl)piperazine-1-yl)-butyl)-aryl carboxamides were prepared and evaluated for binding and function at dopamine D3 (D3R) and D2 receptors (D2R). In this series, we discovered some of the most D3R selective compounds reported to date, (e.g. 8d and 8j >1000-fold D3R-selective over D2R.) In addition, chimeric receptor studies further identified the second extracellular (E2) loop as an important contributor to D3R binding selectivity. Further, compounds lacking the carbonyl group in the amide linker were synthesized and while these amine-linked analogues bound with similar affinities to the amides at D2R, this modification dramatically reduced binding affinities at D3R by >100-fold (e.g. D3RKi for 15b = 393 v. for 8j = 2.6 nM) resulting in compounds with significantly reduced D3R selectivity. This study supports a pivotal role for the D3R E2 loop and the carbonyl group in the 4-phenylpiperazine class of compounds and further reveals a point of separation between structure-activity relationships at D3R and D2R. PMID:21495689

Banala, Ashwini K.; Levy, Benjamin A.; Khatri, Sameer S.; Furman, Cheryse A.; Roof, Rebecca A.; Mishra, Yogesh; Griffin, Suzy A.; Sibley, David R.; Luedtke, Robert R.; Newman, Amy Hauck

2011-01-01

122

Layer silicates modified with 1,4-bis(3-aminopropyl)piperazine for the removal of Th(IV), U(VI) and Eu(III) from aqueous media.  

PubMed

Natural montmorillonite (M) and synthetic kanemite (K) have been functionalized with 1,4-bis(3-aminopropyl)piperazine reacted with methylacrylate to yield new inorganic-organic chelating materials. The original and modified materials were characterized by X-ray diffractometry, textural analysis, SEM and nuclear magnetic nuclei of carbon-13 and silicon-29. The chemically modified clay samples (M-APPMA and K-APPMA) showed modification of its physical-chemical properties including: specific area 45.0m(2)g(-1) (M) to 978.8 m(2)g(-1) (M-APPMA) and 23.5m(2)g(-1) (K) to 898.9 m(2)g(-1) (K-APPMA). The ability of these materials to remove thorium(IV), uranyl(VI) and europium(III) from aqueous solution was followed by a series of adsorption isotherms, which were fitted to non-linear Sips adsorption isotherm model. To achieve the best adsorption conditions the influence of pH and variation of metal concentration were investigated. The energetic effects (Delta(int)H degrees , Delta(int)G degrees and Delta(int)S degrees ) caused by metal ions adsorption were determined through calorimetric titrations. PMID:19604631

Guerra, Denis L; Pinto, Alane A; Viana, Rúbia R; Airoldi, Claudio

2009-11-15

123

1D + 1D ? 1D polyrotaxane, 2D + 2D ? 3D interpenetrated, and 3D self-penetrated divalent metal terephthalate bis(pyridylformyl)piperazine coordination polymers.  

PubMed

Divalent metal coordination polymers containing terephthalate (tere) and bis(4-pyridylformyl)piperazine (bpfp) show diverse and interesting two-dimensional (2D) interpenetrated, three-dimensional (3D) self-penetrated, or one-dimensional (1D) polyrotaxane topological features. Isostructural {[M(tere)(bpfp)(H(2)O)(2)]•4H(2)O}(n) phases (1, Zn; 2, Co) exhibit mutually inclined 2D + 2D ? 3D interpenetration of gridlike layers. {[Cd(4)(tere)(4)(bpfp)(3)(H(2)O)(2)]·8H(2)O}(n) (3) possesses a novel 3,4,8-connected trinodal self-penetrated network with (4.6(2))(2)(4(2)6(16)8(7)10(3))(4(2)6(4))(2) topology. [Zn(2)Cl(2)(tere)(bpfp)(2)](n) (4) is the first example of a 1D + 1D ? 1D polyrotaxane coordination polymer, to the best of our knowledge. Metal coordination geometry plays a crucial role in dictating the overall dimensionality in this system. Thermal decomposition behavior and luminescent properties of the d(10) configuration metal derivatives are also presented herein. PMID:21776990

Wang, Curtis Y; Wilseck, Zachary M; LaDuca, Robert L

2011-09-19

124

Poly[[di-aqua-[?-1,4-bis(pyridin-4-ylmeth-yl)piperazine-?2 N:N?]{?-2,2?-[(1,4-phenyl-ene)bis(-oxy)]di-acetato-?2 O:O?}cobalt(II)] penta-hydrate  

PubMed Central

In the title compound, {[Co(C10H8O6)(C16H20N4)(H2O)2]·5H2O}n, octa­hedrally coordinated CoII ions on crystallographic inversion centres are bound by trans O atoms belonging to two hydro­quinone-O,O?-di­acetate (hqda) anions {systematic name: 2,2?-[(1,4-phenyl­ene)bis­(­oxy)]di­acetate}, two trans-pyridine N-donor atoms from two bis­(pyridin-4-ylmeth­yl)piperazine (4-bpmp) ligands, and two trans aqua ligands. The exobidentate hqda and 4-bpmp ligands form [Co(hqda)(4-bpmp)(H2O)2]n coordination polymer layers parallel to (110) that are anchored into the full crystal structure by O—H?O hydrogen bonding between aqua ligands and ligated hqda O atoms. Disordered water mol­ecules of crystallization occupy incipient channels along [100]. However, these could not modeled reliably and so they were treated with SQUEEZE in PLATON [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystal data take the presence of these mol­ecules into account. The crystal under investigation was twinned by non-merohedry, the twin fraction of the components being 53.3% and 46.7%. Only data from the major twin component were used in the refinement. PMID:24940193

Sample, Alexander D.; LaDuca, Robert L.

2014-01-01

125

Retention of ionisable compounds on high-performance liquid chromatography XVIII: pH variation in mobile phases containing formic acid, piperazine, tris, boric acid or carbonate as buffering systems and acetonitrile as organic modifier.  

PubMed

In the present work dissociation constants of commonly used buffering species, formic acid, piperazine, tris(hydroxymethyl)-aminomethane, boric acid and carbonate, have been determined for several acetonitrile-water mixtures. From these pK(a) values a previous model has been successfully evaluated to estimate pH values in acetonitrile-aqueous buffer mobile phases from the aqueous pH and concentration of the above mentioned buffers up to 60% of acetonitrile, and aqueous buffer concentrations between 0.005 (0.001 mol L(-1) for formic acid-formate) and 0.1 mol L(-1). The relationships derived for the presently studied buffers, together with those established for previously considered buffering systems, allow a general prediction of the pH variation of the most commonly used HPLC buffers when the composition of the acetonitrile-water mobile phase changes during the chromatographic process, such as in gradient elution. Thus, they are an interesting tool that can be easily implemented in general retention models to predict retention of acid-base analytes and optimize chromatographic separations. PMID:19201416

Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

2009-03-20

126

Inhibitors of farnesyl protein transferase. 4-Amido, 4-carbamoyl, and 4-carboxamido derivatives of 1-(8-chloro-6,11-dihydro-5H-benzo[5,6]- cyclohepta[1,2-b]pyridin-11-yl)piperazine and 1-(3-bromo-8-chloro-6,11- dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl)piperazine.  

PubMed

The synthesis of a variety of novel 4-amido, 4-carbamoyl and 4-carboxamido derivatives of 1-(8-chloro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl) piperazine to explore the SAR of this series of FPT inhibitors is described. This resulted in the synthesis of the 4- and 3-pyridylacetyl analogues 45a and 50a, respectively, both of which were orally active but were found to be rapidly metabolized in vivo. Identification of the principal metabolites led to the synthesis of a variety of new compounds that would be less readily metabolized, the most interesting of which were the 3- and 4-pyridylacetyl N-oxides 80a and 83a. Novel replacements for the pyridylacetyl moiety were also sought, and this resulted in the discovery of the 4-N-methyl and 4-N-carboxamidopiperidinylacetyl derivatives 135a and 160a, respectively. All of these derivatives exhibited greatly improved pharmacokinetics. The synthesis of the corresponding 3-bromo analogues resulted in the discovery of the 4-pyridylacetyl N-oxides 83b (+/-) and 85b [11S(-)] and the 4-carboxamidopiperidinylacetamido derivative 160b (+/-), all of which exhibited potent FPT inhibition in vitro. All three showed excellent oral bioavailability in vivo in nude mice and cynomolgus monkeys and exhibited excellent antitumor efficacy against a series of tumor cell lines when dosed orally in nude mice. PMID:9526562

Mallams, A K; Rossman, R R; Doll, R J; Girijavallabhan, V M; Ganguly, A K; Petrin, J; Wang, L; Patton, R; Bishop, W R; Carr, D M; Kirschmeier, P; Catino, J J; Bryant, M S; Chen, K J; Korfmacher, W A; Nardo, C; Wang, S; Nomeir, A A; Lin, C C; Li, Z; Chen, J; Lee, S; Dell, J; Lipari, P; Liu, M

1998-03-12

127

Design, synthesis, and biological evaluation of 3-[4-(2-hydroxyethyl)piperazin-1-yl]-7-(6-methoxypyridin-3-yl)-1-(2-propoxyethyl)pyrido[3,4-b]pyrazin-2(1H)-one, a potent, orally active, brain penetrant inhibitor of phosphodiesterase 5 (PDE5).  

PubMed

We recently described a novel series of aminopyridopyrazinones as PDE5 inhibitors. Efforts toward optimization of this series culminated in the identification of 3-[4-(2-hydroxyethyl)piperazin-1-yl]-7-(6-methoxypyridin-3-yl)-1-(2-propoxyethyl)pyrido[3,4-b]pyrazin-2(1H)-one, which possessed an excellent potency and selectivity profile and demonstrated robust in vivo blood pressure lowering in a spontaneously hypertensive rat (SHR) model. Furthermore, this compound is brain penetrant and will be a useful agent for evaluating the therapeutic potential of central inhibition of PDE5. This compound has recently entered clinical trials. PMID:20196613

Hughes, Robert O; Rogier, D Joseph; Jacobsen, E Jon; Walker, John K; Macinnes, Alan; Bond, Brian R; Zhang, Lena L; Yu, Ying; Zheng, Yi; Rumsey, Jeanne M; Walgren, Jennie L; Curtiss, Sandra W; Fobian, Yvette M; Heasley, Steven E; Cubbage, Jerry W; Moon, Joseph B; Brown, David L; Acker, Brad A; Maddux, Todd M; Tollefson, Mike B; Mischke, Brent V; Owen, Dafydd R; Freskos, John N; Molyneaux, John M; Benson, Alan G; Blevis-Bal, Rhadika M

2010-03-25

128

Development of simultaneous gas chromatography-mass spectrometric and liquid chromatography-electrospray ionization mass spectrometric determination method for the new designer drugs, N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP) and their main metabolites in urine.  

PubMed

To prove the intake of recently controlled designer drugs, N-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP), a simple, sensitive and reliable method which allows us to simultaneously detect BZP, TFMPP and their major metabolite in human urine has been established by coupling gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). GC-MS accompanied by trifluoroacetyl (TFA) derivatization and LC-MS analyses were performed after the enzymatic hydrolysis and the solid phase extraction with OASIS HLB, and BZP, TFMPP and their major metabolites, 4'-hydroxy-BZP (p-OH-BZP), 3'-hydroxy-BZP (m-OH-BZP) and 4'-hydroxy-TFMPP (p-OH-TFMPP), have found to be satisfactorily separated on a semi-micro SCX column with acetonitrile-40 mM ammonium acetate buffer (pH 4) (75:25, v/v) as the eluent. The detection limits produced by GC-MS were estimated to be from 50 ng/ml to 1 microg/ml in the scan mode, and from 200 to 500 ng/ml in the selected ion monitoring (SIM) mode. Upon applying the LC-ESI-MS technique, the linear calibration curves were obtained by using the SIM mode for all analytes in the concentration range from 10 ng/ml to 10 microg/ml. The detection limits ranged from 5 to 40 ng/ml in the scan mode, and from 0.2 to 1 ng/ml in the SIM mode. These results indicate the high reliability and sensitivity of the present procedure, and this procedure will be applicable for proof of intake of BZP and TFMPP in forensic toxicology. PMID:15833296

Tsutsumi, Hiroe; Katagi, Munehiro; Miki, Akihiro; Shima, Noriaki; Kamata, Tooru; Nishikawa, Mayumi; Nakajima, Kunio; Tsuchihashi, Hitoshi

2005-05-25

129

Neuroprotective targets through which 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a sigma receptor ligand, mitigates the effects of methamphetamine in vitro.  

PubMed

Exposure to high or repeated doses of methamphetamine can cause hyperthermia and neurotoxicity, which are thought to increase the risk of developing a variety of neurological conditions. Sigma receptor antagonism can prevent methamphetamine-induced hyperthermia and neurotoxicity, but the underlying cellular targets through which the neuroprotection is conveyed remain unknown. Differentiated NG108-15 cells were thus used as a model system to begin elucidating the neuroprotective mechanisms targeted by sigma receptor antagonists to mitigate the effects of methamphetamine. In differentiated NG108-15 cells, methamphetamine caused the generation of reactive oxygen/nitrogen species, an increase in PERK-mediated endoplasmic reticulum stress and the activation of caspase-3, -8 and -9, ultimately resulting in apoptosis at micromolar concentrations, and necrotic cell death at higher concentrations. The sigma receptor antagonist, 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), attenuated methamphetamine-induced increases in reactive oxygen/nitrogen species, activation of caspase-3, -8 and -9 and accompanying cellular toxicity. In contrast, 1,3-di(2-tolyl)-guanidine (DTG), a sigma receptor agonist, shifted the dose response curve of methamphetamine-induced cell death towards the left. To probe the effect of temperature on neurotoxicity, NG108-15 cells maintained at an elevated temperature (40 °C) exhibited a significant and synergistic increase in cell death in response to methamphetamine, compared to cells maintained at a normal cell culture temperature (37 °C). SN79 attenuated the enhanced cell death observed in the methamphetamine-treated cells at 40 °C. Together, the data demonstrate that SN79 reduces methamphetamine-induced reactive oxygen/nitrogen species generation and caspase activation, thereby conveying neuroprotective effects against methamphetamine under regular and elevated temperature conditions. PMID:24380829

Kaushal, Nidhi; Robson, Matthew J; Rosen, Abagail; McCurdy, Christopher R; Matsumoto, Rae R

2014-02-01

130

21 CFR 520.1807 - Piperazine.  

Code of Federal Regulations, 2012 CFR

...milligrams per pound of body weight. (ii) Indications for use. For removal of large roundworm (Ascaris suum ) and nodular worms (Oesophagostomum spp.). (iii) Limitations. For use in drinking water or feed. Use as sole source of...

2012-04-01

131

21 CFR 520.1807 - Piperazine.  

...your veterinarian for assistance in the diagnosis, treatment, and control of parasitism...your veterinarian for assistance in the diagnosis, treatment, and control of parasitism...your veterinarian for assistance in the diagnosis, treatment, and control of...

2014-04-01

132

Spectroscopic (FT-IR, FT-Raman) investigations and quantum chemical calculations of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl)piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione  

NASA Astrophysics Data System (ADS)

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl) piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione have been investigated experimentally and theoretically using Gaussian09 software package. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Gauge-including atomic orbital 1H NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular Electrostatic Potential was performed by the DFT method and the infrared and Raman intensities have also been reported. First hyperpolarizability is calculated in order to find its role in non-liner optics. The calculated geometrical parameters (SDD) are in agreement with that of similar derivatives. Mulliken’s net charges have been calculated and compared with the atomic natural charges.

Renjith, R.; Mary, Y. Sheena; Panicker, C. Yohannan; Varghese, Hema Tresa; Pakosi?ska-Parys, Magdalena; Van Alsenoy, C.; Al-Saadi, Abdulaziz A.

2014-08-01

133

Synthesis and in vivo evaluation of [(18)F]2-(4-(4-(2-(2-fluoroethoxy)phenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)-dione ([(18)F]FECUMI-101) as an imaging probe for 5-HT1A receptor agonist in nonhuman primates.  

PubMed

The 5-HT1AR partial agonist PET radiotracer, [(11)C]CUMI-101, has advantages over an antagonist radiotracer as it binds preferentially to the high affinity state of the receptor and thereby provides more functionally meaningful information. The major drawback of C-11 tracers is the lack of cyclotron facility in many health care centers thereby limiting widespread clinical or research use. We identified the fluoroethyl derivative, 2-(4-(4-(2-(2-fluoroethoxy)phenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)dione (FECUMI-101) (Ki=0.1nM; Emax=77%; EC50=0.65nM) as a partial agonist 5-HT1AR ligand of the parent ligand CUMI-101. FECUMI-101 is radiolabeled with F-18 by O-fluoroethylation of the corresponding desmethyl analogue (1) with [(18)F]fluoroethyltosylate in DMSO in the presence of 1.6equiv of K2CO3 in 45±5% yield (EOS). PET shows [(18)F]FECUMI-101 binds specifically to 5-HT1AR enriched brain regions of baboon. The specificity of [(18)F]FECUMI-101 binding to 5-HT1AR was confirmed by challenge studies with the known 5-HT1AR ligand WAY100635. These findings indicate that [(18)F]FECUMI-101 can be a viable agonist ligand for the in vivo quantification of high affinity 5-HT1AR with PET. PMID:23816046

Majo, Vattoly J; Milak, Matthew S; Prabhakaran, Jaya; Mali, Pratap; Savenkova, Lyudmila; Simpson, Norman R; Mann, J John; Parsey, Ramin V; Kumar, J S Dileep

2013-09-01

134

Synthesis of Pyrimidine Incorporated Piperazine Derivatives and their Antimicrobial Activity  

PubMed Central

Thiophene substituted chalcones (1a-e) were cyclised with thiourea in presence of potassium hydroxide to get 4-substituted-6-(thiophen-2-yl)pyrimidine-2-thiols (2a-e) which were then stirred with methyl iodide to obtain 4-substituted-2-(methylsulfanyl)-6-(thiophen-2-yl)pyrimidines (3a-e). Compounds (3a-e) were refluxed with different N-methylpiperazine and N-phenylpiperazine to afford 4-substituted-2-(4-methylpiperazin-1-yl)-6-(thiophen-2-yl)pyrimidines (4a-e) and 4-substituted-2-(4-phenylpiperazin-1-yl)-6-(thiophen-2-yl)pyrimidines (5a-e). The structures of all the newly synthesised compounds 4b, 4d, 5a and 5b showed good antibacterial activity at 40?g/mlconcentration. Compounds 4a, 4d, 4e, 5c and 5e showed significant antifungal activity at 40 ?g/ml concentration compared with standard drugs.

Thriveni, K. S.; Padmashali, B.; Siddesh, M. B.; Sandeep, C.

2014-01-01

135

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian;” if not labeled for use by stomach tube or drench, the label shall bear...

2014-04-01

136

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2013 CFR

... See No. 050604 in § 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2013-04-01

137

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2011 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian;” if not labeled for use by stomach tube or drench, the label shall bear...

2011-04-01

138

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2010 CFR

... See No. 050604 in § 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2010-04-01

139

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

... See No. 050604 in § 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2014-04-01

140

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2011 CFR

... See No. 050604 in § 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2011-04-01

141

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2012 CFR

... See No. 050604 in § 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2012-04-01

142

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2013 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian;” if not labeled for use by stomach tube or drench, the label shall bear...

2013-04-01

143

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2010 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian;” if not labeled for use by stomach tube or drench, the label shall bear...

2010-04-01

144

Rigorous modeling of the acid gas heat of absorption in alkanolamine solutions  

SciTech Connect

In this work, we are interested in the estimation of CO{sub 2} and H{sub 2}S heats of absorption in aqueous solutions of alkanolamine: monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). Two methods can be used to calculate the heat release during the absorption phenomenon. The easier which consists of applying the integration of the Gibbs-Helmholtz expression remains inaccurate. The second one, more rigorous, evaluates the heat transfer through an internal energy balance for an open system. The balance expression contains partial molar enthalpies of species in the liquid phase which are calculated from the electrolyte nonrandom-two-liquid (NRTL) excess Gibbs energy model. The calculations carried out in this method can be considered as predictive regarding the NRTL model because its interaction parameters were previously and solely fitted on vapor-liquid equilibrium (VLE) data and not on experimental heat of absorption data. The comparison between both methods and experimental data for the three alkanolamines shows the contribution of this rigorous calculation to better estimate both properties (i.e., solubility and heat) and its usefulness to improve processes. Heats of absorption calculated with the second method can be used in addition to VLE data to fit NRTL parameters. This procedure leads to less-correlated parameters and allows extrapolating the model with more confidence. 63 refs., 10 figs., 6 tabs.

Emilie Blanchon le Bouhelec; Pascal Mougin; Alain Barreau; Roland Solimando [Institut Francais du Petrole, Rueil-Malmaison (France). Departement Thermodynamique et Modelisation Moleculaire

2007-08-15

145

Ion-exchange membranes for bulk separation of acid gases  

SciTech Connect

The field test has continued with PFSA composite membranes. The substrates have been a microporous polypropylene supplied by 3M Co. The membranes have been imbibed with either aqueous solutions of methyldiethanolamine (MDEA) or n-methylpyrrolidone (NMP). Data from five composite membranes have thusfar been obtained and are presented in the following Figure 6. The composite 1 membrane gave erratic performance before it mechanically failed, but most of the observed separation factors were high enough (>35) to be consistent with the initial results from the gel-NE 111 membrane. The separation factor for the other four composites have been consistently low (between 13 and 3). The main difference is that between composite l and the rest we installed an inertial separator to remove excess moisture from the feed stream. This separator may be too efficient and the membranes may be drying out. Another possibility is that the membranes may just not be made well enough and sufficient uncoated pores may exist to subvert the separation efficiency. We tested a membrane which had been removed from the field test rig in our laboratory permeation equipment. Those results are presented in Figures 7 and 8. Again good agreement between the field test and our lab experiments.

Giarratano, P.; Pellegrino, J.J.

1992-01-01

146

Ion-exchange membranes for bulk separation of acid gases  

SciTech Connect

The field test has continued with PFSA composite membranes. The substrates have been a microporous polypropylene supplied by 3M Co. The membranes have been imbibed with either aqueous solutions of methyldiethanolamine (MDEA) or n-methylpyrrolidone (NMP). Data from five composite membranes have thusfar been obtained and are presented in the following Figure 6. The composite 1 membrane gave erratic performance before it mechanically failed, but most of the observed separation factors were high enough (>35) to be consistent with the initial results from the gel-NE 111 membrane. The separation factor for the other four composites have been consistently low (between 13 and 3). The main difference is that between composite l and the rest we installed an inertial separator to remove excess moisture from the feed stream. This separator may be too efficient and the membranes may be drying out. Another possibility is that the membranes may just not be made well enough and sufficient uncoated pores may exist to subvert the separation efficiency. We tested a membrane which had been removed from the field test rig in our laboratory permeation equipment. Those results are presented in Figures 7 and 8. Again good agreement between the field test and our lab experiments.

Giarratano, P.; Pellegrino, J.J.

1992-12-01

147

2-{4-[(1,3-Benzodioxol-5-yl)meth-yl]piperazin-1-yl}pyrimidine  

PubMed Central

In the title compound, C16H18N4O2, known also as peribedil, the dihedral angle between the mean planes of the pyrimidine and benzene rings is 56.5?(8)°. The 1,3-dioxole fragment adopts an envelope conformation with the methyl­ene C atom forming the flap; this atom deviates by 0.232?(3)?Å from the plane defined by the remaining atoms of the 1,3-benzodioxole unit. In the crystal, C—H?? inter­actions between c-glide-related mol­ecules arrange them into columns extending along the c-axis direction. The columns related by a unit translation along the b axis are packed into (100) layers via another C—H?? inter­action involving the pyrimidine ring as an acceptor. PMID:24046690

Wu, Chunli; Li, Jieming; Wei, Huijie; Hang, Ye; Jiang, Yueming

2013-01-01

148

1,4-Diferrocenyl-2-methyl-piperazine-1,4-diium bis-(trifluoro-acetate).  

PubMed

In the title compound, [Fe(2)(C(5)H(5))(2)(C(17)H(24)N(2))](CF(3)COO)(2), the cation possesses a crystallographically imposed inversion centre. The methyl group is disordered over two positions of equal occupancy. The Fe-C bond lengths to the two cyclo-penta-diene rings vary from 2.025?(6) to 2.044?(6)?Å. Inter-molecular N-H?O and C-H?O hydrogen bonds link the cations and anions into a three-dimensional network. PMID:21583407

Chen, Fang

2009-01-01

149

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2013 CFR

...520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Administer by stomach tube. Do not fast horses before or after treatment...used in horses intended for use as food. Federal law restricts this...

2013-04-01

150

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

...520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Administer by stomach tube. Do not fast horses before or after treatment...used in horses intended for use as food. Federal law restricts this...

2014-04-01

151

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2012 CFR

...520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Administer by stomach tube. Do not fast horses before or after treatment...used in horses intended for use as food. Federal law restricts this...

2012-04-01

152

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2011 CFR

...520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Administer by stomach tube. Do not fast horses before or after treatment...used in horses intended for use as food. Federal law restricts this...

2011-04-01

153

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2010 CFR

...520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Administer by stomach tube. Do not fast horses before or after treatment...used in horses intended for use as food. Federal law restricts this...

2010-04-01

154

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: “Federal law restricts this drug to use by or on the order of a licensed veterinarian.”...

2014-04-01

155

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

Code of Federal Regulations, 2012 CFR

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: “Federal law restricts this drug to use by or on the order of a licensed veterinarian.”...

2012-04-01

156

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

Code of Federal Regulations, 2013 CFR

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: “Federal law restricts this drug to use by or on the order of a licensed veterinarian.”...

2013-04-01

157

21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.  

Code of Federal Regulations, 2010 CFR

...but less than 10 1 1/2 10 or heavier 2 1 (2) Indications for use. For removal of immature (fourth stage larvae) and adult hookworms (Ancylostoma caninum, A. braziliense, and Uncinaria stenocephala ) and ascarids (Toxocara...

2010-04-01

158

Synthesis, molecular docking and biological evaluation of metronidazole derivatives containing piperazine skeleton as potential antibacterial agents.  

PubMed

Metronidazole has a broad-spectrum antibacterial activity. Hereby a series of novel metronidazole derivatives were designed and synthesized based on nitroimidazole scaffold in order to find some more potent antibacterial drugs. For these compounds which were reported for the first time, their antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus were tested. These compounds showed good antibacterial activities against Gram-positive strains. Compound 4m represented the most potent antibacterial activity against S. aureus ATCC 25923 with MIC of 0.003 ?g/mL and it showed the most potent activity against S. aureus TyrRS with IC50 of 0.0024 ?M. Molecular docking of 4m into S. aureus tyrosyl-tRNA synthetase active site were also performed to determine the probable binding mode. PMID:24680059

Wang, She-Feng; Yin, Yong; Qiao, Fang; Wu, Xun; Sha, Shao; Zhang, Li; Zhu, Hai-Liang

2014-04-15

159

N-(4-Methyl-piperazin-4-ium-1-yl)dithio-carbamate sesquihydrate  

PubMed Central

In the crystal structure of the title compound, C6H13N3S2·1.5H2O, weak N—H?S inter­actions between the zwitterionic mol­ecules are observed, leading to an extensively folded layered arrangement parallel to (100). There are three crystallographically independent water mol­ecules in the asymmetric unit, which are disordered and only half occupied. PMID:22719506

Mietlarek-Kropidlowska, Anna; Chojnacki, Jaroslaw; Wityk, Pawel; Wieczor, Milosz; Becker, Barbara

2012-01-01

160

Novel tacrine/acridine anticholinesterase inhibitors with piperazine and thiourea linkers.  

PubMed

A new series of substituted tacrine/acridine and tacrine/tacrine dimers with aliphatic or alkylene-thiourea linkers was synthesized and the potential of these compounds as novel human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE) inhibitors with nanomolar inhibition activity was evaluated. The most potent AChE inhibitor was found to be homodimeric tacrine derivative 14a, which demonstrated an IC50 value of 2 nM; this value indicates an activity rate which is 250-times higher than that of tacrine 1 and 7500-times higher than 7-MEOTA 15, the compounds which were used as standards in the study. IC50 values of derivatives 1, 9, 10, 14b and 15 were compared with the dissociation constants of the enzyme-inhibitor complex, Ki1, and the enzyme-substrate-inhibitor complex, Ki2, for. A dual binding site is presumed for the synthesized compounds which possess two tacrines or tacrine and acridine as terminal moieties show evidence of dual site binding. DFT calculations of theoretical desolvation free energies, ??Gtheor, and docking studies elucidate these suggestions in more detail. PMID:25036600

Hamulakova, Slavka; Imrich, Jan; Janovec, Ladislav; Kristian, Pavol; Danihel, Ivan; Holas, Ondrej; Pohanka, Miroslav; Böhm, Stanislav; Kozurkova, Maria; Kuca, Kamil

2014-09-01

161

Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water at 35 70 C  

E-print Network

as it was an experience I will always cherish. George Goff may very well have been the most important member of Dr after he left the group, and I am extremely appreciative of that. Mark Nelson from Air Quality with during my stay at the University of Texas. He has provided me with invaluable experience working in pilot

Rochelle, Gary T.

162

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

Code of Federal Regulations, 2011 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics or other gastrointestinal irritants should not be administered in conjunction with this...

2011-04-01

163

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2011 CFR

...Reserved] (d) Conditions of use. It is used as a drench for horses as follows: (1) Indications for use. An anthelmintic effective against infections of large strongyles (Strongylus vulgaris, S. edentatus ), small strongyles...

2011-04-01

164

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2012 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics and other gastrointestinal irritants should not be administered in conjunction with this...

2012-04-01

165

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2013 CFR

...Reserved] (d) Conditions of use. It is used as a drench for horses as follows: (1) Indications for use. An anthelmintic effective against infections of large strongyles (Strongylus vulgaris, S. edentatus ), small strongyles...

2013-04-01

166

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2010 CFR

...Reserved] (d) Conditions of use. It is used as a drench for horses as follows: (1) Indications for use. An anthelmintic effective against infections of large strongyles (Strongylus vulgaris, S. edentatus ), small strongyles...

2010-04-01

167

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

Code of Federal Regulations, 2010 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics or other gastrointestinal irritants should not be administered in conjunction with this...

2010-04-01

168

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

Code of Federal Regulations, 2012 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics or other gastrointestinal irritants should not be administered in conjunction with this...

2012-04-01

169

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics or other gastrointestinal irritants should not be administered in conjunction with this...

2014-04-01

170

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

Code of Federal Regulations, 2013 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics or other gastrointestinal irritants should not be administered in conjunction with this...

2013-04-01

171

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2010 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics and other gastrointestinal irritants should not be administered in conjunction with this...

2010-04-01

172

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2013 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics and other gastrointestinal irritants should not be administered in conjunction with this...

2013-04-01

173

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics and other gastrointestinal irritants should not be administered in conjunction with this...

2014-04-01

174

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2011 CFR

...animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious disease. As with most anthelmintics, drastic cathartics and other gastrointestinal irritants should not be administered in conjunction with this...

2011-04-01

175

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

...Reserved] (d) Conditions of use. It is used as a drench for horses as follows: (1) Indications for use. An anthelmintic effective against infections of large strongyles (Strongylus vulgaris, S. edentatus ), small strongyles...

2014-04-01

176

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2012 CFR

...Reserved] (d) Conditions of use. It is used as a drench for horses as follows: (1) Indications for use. An anthelmintic effective against infections of large strongyles (Strongylus vulgaris, S. edentatus ), small strongyles...

2012-04-01

177

75 FR 41488 - Agency Information Collection Activities: Submission for OMB Review; Comment Request  

Federal Register 2010, 2011, 2012, 2013

...section in Step 5(a) on Copy 1. The new drug analytes are methylenedioxymethamphetamine (MDMA), commonly known as ``ecstasy''; methyleneamphetamine (MDA), and methylenedioxyethylamphetamine (MDEA). MDA and MDEA are both close chemical...

2010-07-16

178

Synthesis and characterization of novel calix[4]arene piperazine derivative for the extraction of transition metals and dichromate ions  

Microsoft Academic Search

This article displays the synthesis of N-(2-tosylato)ethylpiperazine (ii) and 5,11,17,23-tetra-tert-butyl-25,27-bis-(2-piprazinoethyl)-26,28-dihydroxycalix[4]arene (3). Compounds (ii) and 3 were characterized through elemental analysis, FT-IR, 1H NMR and\\/or 13C NMR studies. The transition metal cations (Hg2+, Co2+, Ni2+, Cu2+, and Cd2+) and dichromate anion were studied by liquid–liquid extraction experiment. The results showed that compound 3 has moderate but selective extraction ability for Hg2+

Fozia Tabassum Minhas; Shahabuddin Memon; M. I. Bhanger

2010-01-01

179

O(2)-dependent efficacy of novel piperidine- and piperazine-based chalcones against the human parasite Giardia intestinalis.  

PubMed

Giardia intestinalis is the most frequent protozoan agent of intestinal diseases worldwide. Though commonly regarded as an anaerobic pathogen, it preferentially colonizes the fairly oxygen-rich mucosa of the proximal small intestine. Therefore, when testing new potential antigiardial drugs, O2 should be taken into account, since it also reduces the efficacy of metronidazole, the gold standard drug against giardiasis. In this study, 46 novel chalcones were synthesized by microwave-assisted Claisen-Schmidt condensation, purified, characterized by high-resolution mass spectrometry, (1)H and (13)C nuclear magnetic resonance, and infrared spectroscopy, and tested for their toxicity against G. intestinalis under standard anaerobic conditions. As a novel approach, compounds showing antigiardial activity under anaerobiosis were also assayed under microaerobic conditions, and their selectivity against parasitic cells was assessed in a counterscreen on human epithelial colorectal adenocarcinoma cells. Among the tested compounds, three [30(a), 31(e), and 33] were more effective in the presence of O2 than under anaerobic conditions and killed the parasite 2 to 4 times more efficiently than metronidazole under anaerobiosis. Two of them [30(a) and 31(e)] proved to be selective against parasitic cells, thus representing potential candidates for the design of novel antigiardial drugs. This study highlights the importance of testing new potential antigiardial agents not only under anaerobic conditions but also at low, more physiological O2 concentrations. PMID:24217695

Bahadur, Vijay; Mastronicola, Daniela; Tiwari, Hemandra Kumar; Kumar, Yogesh; Falabella, Micol; Pucillo, Leopoldo Paolo; Sarti, Paolo; Giuffrè, Alessandro; Singh, Brajendra Kumar

2014-01-01

180

O2-Dependent Efficacy of Novel Piperidine- and Piperazine-Based Chalcones against the Human Parasite Giardia intestinalis  

PubMed Central

Giardia intestinalis is the most frequent protozoan agent of intestinal diseases worldwide. Though commonly regarded as an anaerobic pathogen, it preferentially colonizes the fairly oxygen-rich mucosa of the proximal small intestine. Therefore, when testing new potential antigiardial drugs, O2 should be taken into account, since it also reduces the efficacy of metronidazole, the gold standard drug against giardiasis. In this study, 46 novel chalcones were synthesized by microwave-assisted Claisen-Schmidt condensation, purified, characterized by high-resolution mass spectrometry, 1H and 13C nuclear magnetic resonance, and infrared spectroscopy, and tested for their toxicity against G. intestinalis under standard anaerobic conditions. As a novel approach, compounds showing antigiardial activity under anaerobiosis were also assayed under microaerobic conditions, and their selectivity against parasitic cells was assessed in a counterscreen on human epithelial colorectal adenocarcinoma cells. Among the tested compounds, three [30(a), 31(e), and 33] were more effective in the presence of O2 than under anaerobic conditions and killed the parasite 2 to 4 times more efficiently than metronidazole under anaerobiosis. Two of them [30(a) and 31(e)] proved to be selective against parasitic cells, thus representing potential candidates for the design of novel antigiardial drugs. This study highlights the importance of testing new potential antigiardial agents not only under anaerobic conditions but also at low, more physiological O2 concentrations. PMID:24217695

Bahadur, Vijay; Mastronicola, Daniela; Tiwari, Hemandra Kumar; Kumar, Yogesh; Falabella, Micol; Pucillo, Leopoldo Paolo; Sarti, Paolo

2014-01-01

181

The 5-substituted piperazine as a novel secondary pharmacophore greatly improving the physical properties of urea-based  

E-print Network

,b Bruce D. Hammockb and Ya-Qiu Longa,* a State Key Laboratory of Drug Research, Shanghai Institute in the metabolism of endogenous chemical mediators such as arachidonic acid, linoleic acid, and other lipid epoxides. Epoxides of arachidonic acid (epoxyeicosatrienoic acids or EETs) are known effectors of blood pressure3

Hammock, Bruce D.

182

CO2 Capture by Absorption with Potassium Carbonate  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The best solvent and process configuration, matrix with MDEA/PZ, offers 22% and 15% energy savings over the baseline and improved baseline, respectively, with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal. The stripper rate model shows that a ''short and fat'' stripper requires 7 to 15% less equivalent work than a ''tall and skinny'' one. The stripper model was validated with data obtained from pilot plant experiments at the University of Texas with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ under normal pressure and vacuum conditions using Flexipac AQ Style 20 structured packing. Experiments with oxidative degradation at low gas rates confirm the effects of Cu{sup +2} catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu{sup +2}. At 150 C, the half life of 30% MEA with 0.4 moles CO{sub 2}/mole amine is about 2 weeks. At 100 C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO{sub 2} loading and decreases with MEA concentration. The base case corrosion rate in 5 M MEA/1,2M PZ is 22 mpy. With 1 wt% heat stable salt, the corrosion rate increases by 50% to 160% in the order: thiosulfate< oxalate

Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Jason Davis; Marus Hiilliard; Qing Xu; David Van Wagener; Jorge M. Plaza

2006-12-31

183

Rapid and simple LC-MS/MS screening of 64 novel psychoactive substances using dried blood spots.  

PubMed

The range of novel psychoactive substances (NPS) including phenethylamines, cathinones, piperazines, tryptamines, etc. is continuously growing. Therefore, fast and reliable screening methods for these compounds are essential and needed. The use of dried blood spots (DBS) for a fast straightforward approach helps to simplify and shorten sample preparation significantly. DBS were produced from 10 µl of whole blood and extracted offline with 500 µl methanol followed by evaporation and reconstitution in mobile phase. Reversed-phase chromatographic separation and mass spectrometric detection (RP-LC-MS/MS) was achieved within a run time of 10 min. The screening method was validated by evaluating the following parameters: limit of detection (LOD), matrix effect, selectivity and specificity, extraction efficiency, and short-term and long-term stability. Furthermore, the method was applied to authentic samples and results were compared with those obtained with a validated whole blood method used for routine analysis of NPS. LOD was between 1 and 10 ng/ml. No interference from matrix compounds was observed. The method was proven to be specific and selective for the analytes, although with limitations for 3-FMC/flephedrone and MDDMA/MDEA. Mean extraction efficiency was 84.6 %. All substances were stable in DBS for at least a week when cooled. Cooling was essential for the stability of cathinones. Prepared samples were stable for at least 3 days. Comparison to the validated whole blood method yielded similar results. DBS were shown to be useful in developing a rapid screening method for NPS with simplified sample preparation. PMID:23868723

Ambach, Lars; Hernández Redondo, Ana; König, Stefan; Weinmann, Wolfgang

2014-04-01

184

77 FR 39737 - Controlled Substances: Proposed Adjustment to the Aggregate Production Quotas for 2012  

Federal Register 2010, 2011, 2012, 2013

...4-Methylenedioxy-N-ethylamphetamine (MDEA)...... 15 g......................... 24 g. 3,4-Methylenedioxymethamphetamine (MDMA).......... 22 g......................... 30 g. 3,4-Methylenedioxypyrovalerone...

2012-07-05

185

4-(2-Fluoro-benzo-yl)-1-[2-(4-hy-droxy-phen-yl)-2-oxoeth-yl]piperazin-1-ium trifluoro-acetate  

PubMed Central

In the crystal structure of the title compound, C19H20FN2O3 +·C2F3O2 ?, N—H?O and O—H?O hydrogen bonds link two cations and two anions into a 22-atom ring. These rings are further linked into a three dimensional network by weak C—H?O contacts. PMID:23284541

Bian, Fuyong; Jin, Yi; Chi, Shaoming; Shi, Guojun; Xu, Sichuan

2012-01-01

186

4-(2-Fluoro-benzo-yl)-1-[2-(4-hy-droxy-phen-yl)-2-oxoeth-yl]piperazin-1-ium trifluoro-acetate.  

PubMed

In the crystal structure of the title compound, C(19)H(20)FN(2)O(3) (+)·C(2)F(3)O(2) (-), N-H?O and O-H?O hydrogen bonds link two cations and two anions into a 22-atom ring. These rings are further linked into a three dimensional network by weak C-H?O contacts. PMID:23284541

Bian, Fuyong; Jin, Yi; Chi, Shaoming; Shi, Guojun; Xu, Sichuan

2012-11-01

187

Universit degli Studi di Roma "La Sapienza" Via di Grottarossa 1037 00189 Roma  

E-print Network

semestre) *************(M-DEA01) *************(M-PED01) *************(M-PSI08) Anatomia Umana e Clinica I - II (I anno, I e II semestre) *************(BIO16) *************(BIO16) *************(BIO16) Anatomia

Guidoni, Leonardo

188

Design of the Williams Field Services Mobile Bay ethane recovery plant  

SciTech Connect

ABB Randall designed, procured and constructed a two train expander plant with a base case design capacity of 525 MMscfd and a hydraulic design capacity of 600 MMscfd. Randall has used its Recycle Reflux Process, proven in other installations, resulting in a calculated ethane recovery of 93% at 525 MMscfd (78% at 600 MMscfd) and ethane rejection. Liquids production creates a design challenge due to the presence of acid gas components such as CO{sub 2}, H{sub 2}S, mercaptans and COS, with the latter three causing the product to fail the copper strip test. The challenge is to remove the components to the required level with minimum cost and in an operator-friendly manner. The following combinations of processes were reviewed: DGA, MDEA and Merichem, COS Hydrolysis and MDEA, MDEA and KOH, Sulfinol, MDEA and SulfaClean; and MDEA and mol sieve. This paper will give a brief description, an illustration and economic impact information of each one. Lastly, the rationale behind the selection of the COS Hydrolysis bed, MDEA absorber and provisions to add an iron sponge bed is discussed.

Vogel, D.C.; McKenzie, D.

1999-07-01

189

Optical Properties of Acrylate-Based Negative-Type Photoresist and Its Application to Optical Waveguide Fabrication  

Microsoft Academic Search

In this article, we present some of the optical properties of a polymeric acrylate-based photoresist material called PNME, by its principal components, which are pentaerythritol triacrylate, n-methyldiethanolamine, and eosin. The refractive index and absorption spectra were measured. Because of the low absorption of PNME in the datacom and telecom regions, PNME was studied with respect to its suitability for the

Pavol Gustafik; Okihiro Sugihara; Naomichi Okamoto

2004-01-01

190

Synthesis and Evaluation of Anti-acetylcholinesterase Activity of 2-(2-(4-(2-Oxo-2-phenylethyl)piperazin-1-yl) ethyl)Isoindoline-1,3-dione Derivatives with Potential Anti-Alzheimer Effects  

PubMed Central

Objective(s): Alzheimer's disease (AD) is a neurodegenerative disorder in elderly patients. Decrease in cholinergic neurotransmission is the main known cause in the pathophysiology of the disease. Improvement and potentiation of the cholinergic system could be beneficial for treatment of the AD. Acetylcholinesterase inhibitors such as donepezil can enhance the duration of action of acetylcholine (Ach) and therefore, through this mechanism improve the symptoms of AD. Materials and Methods: In the current study, based on the potential inhibitory activity of phthalimide derivatives towards acetylcholinesterase enzyme, a new series of phthalimide-based compounds were synthesized (4a-4e) and anti-acetylcholinesterase effect was assessed using Ellman's test. Compound 4b with 4-Fluorophenyl moiety was the most potent derivative in this series (IC50 = 16.42 ± 1.07 µM). It was shown that, none of the synthesized compounds showed superior inhibitory potency compared to donepezil (0.41 ± 0.09 µM) as a reference drug. Conclusion: The new synthesized phthalimide based analogs could function as potential acetylcholinesterase inhibitors. Further studies are necessary for development of potent analogs. PMID:24379961

Aliabadi, Alireza; Foroumadi, Alireza; Mohammadi-Farani, Ahmad; Garmsiri Mahvar, Mahdi

2013-01-01

191

Synthesis and evaluation of 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-(2-(4-substitutedpiperazin-1-yl)acetyl)piperazin-1-yl)quinoline-3-carboxylic acid derivatives as anti-tubercular and antibacterial agents.  

PubMed

A series of twenty two novel 1-cyclopropyl-6-fluoro-4-oxo-7-(4-substitutedpiperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid analogues were synthesized, characterized ((1)H NMR, (13)C NMR and LCMS) and screened for their in vitro anti-tubercular and antibacterial activity. Many of these compounds exhibited MIC values in the range 7.32-136.10 ?M against Mycobacterium tuberculosis H37Rv. Eight compounds were further subjected to cytotoxic studies. Furthermore, the title compounds were screened for antibacterial activity against Staphylococcus aureus ATCC 29213 (gram positive) and Escherichia coli ATCC 25922 (gram negative) bacteria. Many of these compounds exhibited MIC values in the range 0.44-34.02 ?M. Compound 3f was found to be the most active with an MIC of 0.44 and 0.8 ?M respectively against both the strains. In general, the antibacterial activity of title compounds was more prominent. PMID:24333580

Suresh, Narva; Nagesh, Hunsur Nagendra; Renuka, Janupally; Rajput, Vikrant; Sharma, Rashmi; Khan, Inshad Ali; Kondapalli Venkata Gowri, Chandra Sekhar

2014-01-01

192

Discovery of a novel sub-class of ROMK channel inhibitors typified by 5-(2-(4-(2-(4-(1H-Tetrazol-1-yl)phenyl)acetyl)piperazin-1-yl)ethyl)isobenzofuran-1(3H)-one.  

PubMed

A sub-class of distinct small molecule ROMK inhibitors were developed from the original lead 1. Medicinal chemistry endeavors led to novel ROMK inhibitors with good ROMK functional potency and improved hERG selectivity. Two of the described ROMK inhibitors were characterized for the first in vivo proof-of-concept biology studies, and results from an acute rat diuresis model confirmed the hypothesis that ROMK inhibitors represent new mechanism diuretic and natriuretic agents. PMID:24075732

Tang, Haifeng; de Jesus, Reynald K; Walsh, Shawn P; Zhu, Yuping; Yan, Yan; Priest, Birgit T; Swensen, Andrew M; Alonso-Galicia, Magdalena; Felix, John P; Brochu, Richard M; Bailey, Timothy; Thomas-Fowlkes, Brande; Zhou, Xiaoyan; Pai, Lee-Yuh; Hampton, Caryn; Hernandez, Melba; Owens, Karen; Roy, Sophie; Kaczorowski, Gregory J; Yang, Lihu; Garcia, Maria L; Pasternak, Alexander

2013-11-01

193

Design, Synthesis, and Pharmacological Evaluation of Novel 2-(4-substituted piperazin-1-yl)1, 8 Naphthyridine 3-Carboxylic Acids as 5-HT3 Receptor Antagonists for the Management of Depression.  

PubMed

1, 8-naphthyridine-3-carboxylic acid analogs were synthesized and found to possess potential 5-HT3 receptor antagonism as well as antidepressant-like activity. Initially, 5-HT3 receptor antagonism of all the compounds was determined in the form of pA2 value against agonist 2-methyl 5-HT in longitudinal muscle-myenteric plexus preparation from guinea-pig ileum. Among all the compounds tested, compound 7a demonstrated most promising pA2 value of 7.6. Subsequently, all the compounds were evaluated for antidepressant activity using forced swim test and tail suspension test in mice. Compounds 7a, 7d, 7f, 7h, and 7i exhibited significant (p < 0.05) antidepressant-like activity as compound to vehicle-treated group. Importantly, none of the tested compound affected locomotor activity of mice at tested dose levels. PMID:24903617

Dhar, Arghya K; Mahesh, Radhakrishnan; Jindal, Ankur; Devadoss, Thangaraj; Bhatt, Shvetank

2014-12-01

194

Studies on the metabolism and the toxicological analysis of the nootropic drug fipexide in rat urine using gas chromatography–mass spectrometry  

Microsoft Academic Search

Qualitative studies are described on the metabolism and the toxicological analysis of the nootropic fipexide (FIP) in rat urine using gas chromatography–mass spectrometry (GC–MS). FIP was extensively metabolized to 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), 4-chlorophenoxyacetic acid, 1-[2-(4-chlorophenoxy)acetyl]piperazine, N-(4-hydroxy-3-methoxy-benzyl)piperazine, piperazine, N-(3,4-methylenedioxybenzyl)ethylenediamine, and N-[2-(4-chlorophenoxy)acetyl]ethylenediamine. The authors’ systematic toxicological analysis (STA) procedure using full-scan GC–MS after acid hydrolysis of one urine aliquot, liquid-liquid extraction and acetylation

Roland F. Staack; Hans H. Maurer

2004-01-01

195

Chukwuemeka I. Okoye Carbon Dioxide Solubility and Absorption Rate in  

E-print Network

Copyright by Chukwuemeka I. Okoye 2005 #12;Carbon Dioxide Solubility and Absorption Rate _______________________ Nicholas A. Peppas #12;Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O for. #12;iii Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O

Rochelle, Gary T.

196

Canadian Gas Treating Solvent Quality Control - Unique Challenges  

Microsoft Academic Search

Unusual gas compositions, harsh weather conditions, and remote producing locations have posed significant problems for the Canadian Gas Treating Industry. A few amine types, including DEA, MDEA, and Sulfinol-D™ are widely used in Canadian gas treating facilities. Process conditions cause these amines to degrade over time, with each amine type producing a unique set of degradation products. The most common

Steve Carlson; Steve Canter; Jim Jenkins

197

Rapid analysis of illicit drugs by mass spectrometry: Results from seizures in Ireland  

Microsoft Academic Search

A gas chromatographic procedure with mass spectrometric detection (GC-MS) was established to determine the principal amphetamines, methylenedioxymethylamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) and methylenedioxyamphetamine (MDA), cocaine and pharmacologically active impurities in 'ecstasy' tablets. The procedure was developed and optimised by combining the individual methods for the various drugs of abuse available in the literature into a single GC-MS run. New variants of

Donnacha O’Connell; James J. A. Heffron

2000-01-01

198

Z .Fluid Phase Equilibria 168 2000 241258 www.elsevier.nlrlocaterfluid  

E-print Network

in MDEA solutions neutralized with sulfuric acid. The physical solubility is seen to decrease absorption of acid gases by alkanolamines has found application in a wide variety of industries, including the processing of natural gas and the removal of CO from synthesis gas in the2 production of hydrogen or ammonia

Rochelle, Gary T.

199

Integration of GC\\/EI-MS and GC\\/NCI-MS for simultaneous quantitative determination of opiates, amphetamines, MDMA, ketamine, and metabolites in human hair  

Microsoft Academic Search

In this paper, the possibility of using a multiple ionization mode approach of GC\\/MS was developed for the simultaneous hair testing of common drugs of abuse in Asia, including amphetamines (amphetamine, AP; methamphetamine, MA; methylenedioxy amphetamine, MDA; methylenedioxy methamphetamine, MDMA; methylenedioxy ethylamphetamine, MDEA), ketamine (ketamine, K; norketamine, NK), and opiates (morphine, MOR; codeine, COD; 6-acetylmorphine, 6-AM). This strategy integrated the

Ya-Hsueh Wu; Keh-liang Lin; Su-Chin Chen; Yan-Zin Chang

2008-01-01

200

Arsenic in Natural Gas: Analysis and Characterization of Pipeline Solids by H NMR and Other Methods  

Microsoft Academic Search

Natural gas from the Abo gas field in New Mexico is known to contain arsenic in the form of tertiary alkylarsines. Deposition of alkylarsine sulfides near the pressure regulation equipment in the transmission lines may cause serious operational problems. 'H NMR spectra of CDCl3 solutions of the pure compounds, trimethylarsine sulfide (TMAS), dimethylethylarsine sulfide (DMEAS) and methyldiethylarsine sulfide (MDEAS) were

W. Delgado-morales; R. A. Zingaro; M. S. Mohan

1994-01-01

201

Impaired cognitive performance in drug free users of recreational ecstasy (MDMA)  

Microsoft Academic Search

OBJECTIVESEcstasy (3,4-methylenedioxymethamphetamine (MDMA) and related congerers: MDA, MDEA) is the name given to a group of popular recreational drugs. Animal data raise concern about neurotoxic effects of high doses of ecstasy on central serotonergic systems. The threshold dose for neurotoxicity in humans is not clear and serotonin is involved in several functions including cognition. The purpose of this study was

Euphrosyne Gouzoulis-Mayfrank; Jörg Daumann; Frank Tuchtenhagen; Susanne Pelz; Steffanie Becker; Hans-Jürgen Kunert; Bruno Fimm; Henning Sass

2000-01-01

202

Novel new ester quaternaries for improved performance benefits as rinse cycle fabric softeners  

Microsoft Academic Search

A number of new diesterquats and anidoester quats were synthesized and tested for biodegradation and softening. Methyldiethanolamine,\\u000a 3-methoxylpropylamine, diethanolaminopropylamine, aminoethylethanolamine, dimethylethanolamine, and diethanolamine were reacted,\\u000a either “as is” or after alkoxylation, with tallow fatty acid and further converted into dialkyl quats. The diesterquat from\\u000a diethanolisopropanolamine was by far the best of the ester quats synthesized in overall biodegradation, softening, and

Floyd E. Friedli; Robert Keys; C. Joe Toney; Owen Portwood; Dave Whittlinger; Markus Doerr

2001-01-01

203

Effets comparés du Piribédil et de trois de ses métabolites sur le système extrapyramidal du rat  

Microsoft Academic Search

Summary The effects of Piribedil on central dopaminergic receptors were compared with the effects elicited by 3 metabolites of this drug. One of them S-584=[1-(2-pyrimidyl)-4 (3–4 dihydroxyphenyl) piperazine] showed dopaminergic stimulant properties when administered by the i.p. route, in unilateral nigro-neostriatal lesioned rats. Other metabolites: S 3284=[1-(2-pyrimidyl)1N-oxydo-4 piperonyl piperazine] and S 3473=[1-(5 hydroxy 2 pyrimidyl)-4 piperonyl piperazine] were ineffective.

J.-C. Poignant; F. Lejeune; E. Malecot; M. Petitjean; G. Regnier; R. Canevari

1974-01-01

204

Cinnarizinium picrate  

PubMed Central

In the title salt {systematic name: 4-diphenyl­methyl-1-[(E)-3-phenyl­prop-2-en-1-yl]piperazin-1-ium 2,4,6-trinitro­pheno­late), C26H29N2 +·C6H2N3O7 ?, the cinnarizinium cation is protonated at the piperazine N atom connected to the styrenylmethyl group; the piperazine ring adopts a distorted chair conformaiton. In the crystal, bifurcated N—H?(O,O) hydrogen bonds link the components into two-ion aggregates. PMID:22719532

Song, Yanxi; Chidan Kumar, C. S.; Nethravathi, G. B.; Naveen, S.; Li, Hongqi

2012-01-01

205

Acidic gas capture by diamines  

DOEpatents

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

Rochelle, Gary (Austin, TX); Hilliard, Marcus (Missouri City, TX)

2011-05-10

206

Acta Poloniae Pharmaceutica. Volume 26, Number 3, 1969.  

National Technical Information Service (NTIS)

Contents: Synthesis of some piperidyl esters of acetyltropic and diphenylacetic acids; Alkylation of 4-acyl-4-phenylpiperidines; Synthesis of 2-aminoethyl-hydrazine and some of its derivatives; gamma-(N-2-pyridono)-propyl-piperazines substituted at positi...

1969-01-01

207

The effect of low-level thiabendazole on gastro-intestinal parasites of goats  

E-print Network

cactus contortus, ~osterta ta ~st rta t and Trichostron lus axei in cattle under Florida conditions. He concluded that only when combined w1th hexachlorethane and piperazine citrate phenothiazine significantly reduced the numbers of these genera. l7... cactus contortus, ~osterta ta ~st rta t and Trichostron lus axei in cattle under Florida conditions. He concluded that only when combined w1th hexachlorethane and piperazine citrate phenothiazine significantly reduced the numbers of these genera. l7...

Paculdo, Damaso Jurado

2012-06-07

208

ABBREVIATiONS: GABAR, y-aminobutyric acid type A receptor; GABA, y-aminobutyric acid; HEPES, 4-(2-hydroxyethyl)-1 -piperazineethane-sulfonic acid; PIPES, piperazine-N,N'-bis(2-ethanesulfonic acid); DZP, diazepam; ZOL, zolpidem; I-V. current-voltage, Vh, m  

E-print Network

, diazepam; ZOL, zolpidem; I-V. current-voltage, Vh, membrane holding potential; p-gal, f3-galactosidase; GFP- containing receptors (26 MM). a533y2L receptors were zinc and diazepam sensitive but zolpidem insensitive

Abraham, Nader G.

209

Hydrothermal Synthesis and Characterization of Two Mixed Valence Piperazine-Vanadium Phosphates: (C 4H 12N 2)(H 3O)[(VOPO 4) 4(H 2O)H 2PO 4]·3H 2O and (C 4H 12N 2)[(VO)(VO 2) 2(H 2O)(PO 4) 2  

NASA Astrophysics Data System (ADS)

Two new phases, (C 4H 12N 2)(H 3O)[(VOPO 4) 4(H 2O)H 2PO 4]·3H 2O (1) and (C 4H 12N 2)[(VO)(VO 2) 2(H 2O)(PO 4) 2] (2) have been synthesized hydrothermally and characterized by single crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility. Compound 1 has an open-framework structure and is closely related to (VO) 2(PO 4) 2H 2PO 4·N 2C 2H 10, whereas compound 2 has layered structure containing discrete trinuclear [V 3O 13(H 2O)] corner-sharing units. In both structures the V atoms are mixed-valence, V IV and V V, with octahedral and trigonal bipyramidal geometry. Crystal data: (C 4H 12N 2)(H 3O)[(VOPO 4) 4(H 2O)H 2PO 4]·3H 2O 1, monoclinic, space group P2/ n (No. 13), a=9.6448(7) Å, b=8.8770(7) Å, c=14.813(1) Å, ?=91.936(2)°, Z=4, R1=0.0717; (C 4H 12N 2)[(VO)(VO 2) 2(H 2O)(PO 4) 2] 2, triclinic, space group Poverline1 (No. 2); a=6.1650(5) Å, b=10.8206(9) Å, c=11.854(1) Å, ?=66.598(1)°, ?=76.008(2)°, ?=83.439(2)°, Z=2, R1=0.0467.

Do, Junghwan; Bontchev, Ranko P.; Jacobson, Allan J.

2000-11-01

210

Structure-activity-relationship study of N6-(2(4-(1H-indol-5-yl)piperazin-1-yl)ethyl)-N6-propyl-4,5,6,7-tetrahydrobenzo[d]thiazole-2,6-diamine analogues: Development of highly selective D3 dopamine receptor agonists along with a highly potent D2/D3 agonist and their pharmacological characterization  

PubMed Central

In our effort to develop multifunctional drugs against Parkinson’s disease, a structure-activity-relationship study was carried out based on our hybrid molecular template targeting D2/D3 receptors. Competitive binding with [3H]spiroperidol was used to evaluate affinity (Ki) of test compounds. Functional activity of selected compounds in stimulating [35S]GTP?S binding was assessed in CHO-cells expressing either human D2 or D3 receptors. Our results demonstrated development of highly selective compounds for D3 receptor ((?)-40; Ki D3 = 1.84 nM, D2/D3 = 583.2, (?)-45; Ki D3 = 1.09 nM, D2/D3 = 827.5). Functional data identified (?)-40 (EC50 D2 = 114 nM and D3 = 0.26 nM, D2/D3 = 438) as one of the highest D3 selective agonists known to date. In addition, high affinity, non-selective, D3 agonist, (?)-19 (EC50 D2 = 2.96 nM and D3 = 1.26 nM), was also developed. Lead compounds with antioxidant activity were evaluated using an in vivo PD animal model. PMID:22642365

Johnson, Mark; Antonio, Tamara; Reith, Maarten E. A.; Dutta, Aloke K.

2012-01-01

211

Modification of agonist binding moiety in hybrid derivative 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-1-ol/-2-amino versions: Impact on functional activity and selectivity for dopamine D2/D3 receptors  

PubMed Central

The goal of the present study was to explore, in our previously developed hybrid template, the effect of introduction of additional heterocyclic rings (mimicking catechol hydroxyl groups as bioisosteric replacement) on selectivity and affinity for the D3 versus D2 receptor. In addition, we wanted to explore the effect of derivatization of functional groups of the agonist binding moiety in compounds developed by us earlier from the hybrid template. Binding affinity (Ki) of the new compounds was measured with tritiated spiperone as the radioligand and HEK-293 cells expressing either D2 or D3 receptors. Functional activity of selected compounds was assessed in the GTP?S binding assay. In the imidazole series, compound 10a exhibited the highest D3 affinity whereas the indole derivative 13 exhibited similar high D3 affinity. Functionalization of the amino group in agonist (+)-9d with different sulfonamides derivatives improved the D3 affinity significantly with (+)-14f exhibiting the highest affinity. However, functionalization of the hydroxyl and amino groups of 15 and (+)-9d, known agonist and partial agonist, to sulfonate ester and amide in general modulated the affinity. In both cases loss of agonist potency resulted from such derivatization. PMID:23623679

Gopishetty, Bhaskar; Zhang, Suhong; Kharkar, Prashant S.; Antonio, Tamara; Reith, Maarten; Dutta, Aloke K.

2013-01-01

212

Molecular Characterization of the mde Operon Involved in L-Methionine Catabolism of Pseudomonas putida  

Microsoft Academic Search

A 15-kb region of Pseudomonas putida chromosomal DNA containing the mde operon and an upstream regulatory gene (mdeR) has been cloned and sequenced. The mde operon contains two structural genes involved in L-methionine degradative metabolism: the already-identified mdeA, which encodes L-methionine g-lyase (H. Inoue, K. Inagaki, M. Sugimoto, N. Esaki, K. Soda, and H. Tanaka. J. Biochem. (Tokyo) 117:1120-1125, 1995),

HIROYUKI INOUE; KENJI INAGAKI; SHIN-ICHI ERIGUCHI; TAKASHI TAMURA; NOBUYOSHI ESAKI; KENJI SODA; HIDEHIKO TANAKA

1997-01-01

213

An Absorption Model for Solvent XDS on Removing Organosulfurs from High Sour Natural Gas  

Microsoft Academic Search

A novel solvent, XDS, was developed to remove H2S, organic sulfur, and acid compounds in the crude high sour natural gas. Results showed that XDS solvent has a remarkable organic sulfur selectivity compared with the industrial conventional solvent, MDEA. Sulfur compound could reach 66.1 mg\\/m at 50% XDS solvent, gas to oil ratio 130 and 40°C. The organic sulfur removing

J.-H. Zhang; B.-X. Shen; J.-C. Liu; H. Sun

2010-01-01

214

World sulfur production: Petroleum derived as of January 1, 1996  

SciTech Connect

Data are presented on world sulfur production by company within each country. The table lists the source of the sulfur (refinery gases, natural gas, acid gas, sour gas, oil sands, associated gas, or resid asphalt), the type of process used to recovery the sulfur, plant design capacity, and production. Processes include Claus, chlorination, Scot, Sulfinol, Sulfreen, modified Claus, bed absorption, MDEA-LoCat, Selectox, Parsons, SNEA, Comprimo, Uhde, Stretford, and Wellman-Lord.

NONE

1996-07-01

215

HâS-removal processes for low-Btu coal gas  

Microsoft Academic Search

Process descriptions are provided for seven methods of removing HâS from a low-Btu coal-derived gas. The processes include MDEA, Benfield, Selexol, Sulfinol, Stretford, MERC Iron Oxide, and Molecular Sieve. Each of these processes was selected as representing a particular category of gas treating (e.g., physical solvent systems). The open literature contains over 50 processes for HâS removal, of which 35

1979-01-01

216

Surface composition and protein adsorption of polyurethane membrane  

Microsoft Academic Search

Membranes of uncomplexed polyurethanes (PUs) were prepared by hydroxyl-terminated polybutadiene (HTPB), 4,4?-dicyclohexylmethane diisocyanate (H12MDI) and 1,4-butane diol (1,4-BD). While complexed PUs were prepared by using N-methyl diethanol (MDEA) as the chain extender of which the tertiary amines were complexed with cupric ions. Molar ratio of protein adsorption of fibrinogen to albumin (F\\/A molar ratio) on polymer surface was measured. The

Shih-Liang Huang; Cheng-Fang Ou; Juin-Yih Lai

1999-01-01

217

Quantitative determination of amphetamines, cocaine, and opiates in human hair by gas chromatography\\/mass spectrometry  

Microsoft Academic Search

Hair of young subjects (N=36) suspected for drug abuse was analysed for morphine, codeine, heroin, 6-acetylmorphine, cocaine, methadone, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA). The analysis of morphine, codeine, heroin, 6-acetylmorphine, cocaine, and methadone in hair included incubation in methanol, solid-phase extraction, derivatisation by the mixture of propionic acid anhydride and pyridine, and gas chromatography\\/mass spectrometry (GC\\/MS).

L Skender; V Kara?i?; I Br?i?; A Bagari?

2002-01-01

218

Pathology of deaths associated with \\  

Microsoft Academic Search

AIMS: To study the postmortem pathology associated with ring substituted amphetamine (amphetamine derivatives) misuse. METHODS: The postmortem findings in deaths associated with the ring substituted amphetamines 3,4-methylenedioxymethyl-amphetamine (MDMA, ecstasy) and 3,4-methylenedioxyethylamphetamine (MDEA, eve) were studied in seven young white men aged between 20 and 25 years. RESULTS: Striking changes were identified in the liver, which varied from foci of individual

C M Milroy; J C Clark; A R Forrest

1996-01-01

219

A family of novel Mn3Ln4 clusters displaying single-molecule magnet behavior.  

PubMed

Using 3-methyloxysalicylaldoxime (mosaoH2) and N-methyl diethanolamine (N-mdeaH2) as coligands, a family of heptanuclear Mn/Ln heterometallic compounds [Mn(II)Mn(III)2Ln(III)4(mosao)2(mosaoH)4(piv)4(N-mdea)4]·xMeCN [Ln = Dy(), Tb() and Y(), pivH = pivalic acid] have been prepared. The crystal structures of were obtained, and their core consists of two Mn(III)Ln2(?3-OR)2 (RO(2-) = N-mdea(2-)) triangles linked to a central Mn(II) atom. A dc magnetic susceptibility study reveals that single-ion effects of the Ln ions are dominant in compounds and . As for compound , which contains diamagnetic Y ions, the magnetic interactions between Mn ions via oximate NO bridges are revealed to be ferromagnetic. Fitting of the ?mT vs. T data gives g = 1.96 and J = 1.12 cm(-1), affording a S = 13/2 ground state. All of the three compounds exhibit frequency-dependent out-of-phase ac susceptibility signals indicative of slow magnetization relaxation and potential SMM behavior. Among them, and display the out-of-phase ? peak maximum above 2.0 K. Fitting of the ac susceptibility data to the Arrhenius law gives an energy barrier Ueff = 9.27/13.83 K for and , respectively. PMID:25273696

Chen, Hui; Ma, Cheng-Bing; Hu, Ming-Qiang; Wen, Hui-Min; Chen, Chang-Neng

2014-10-22

220

PUTATIVE AGMATINASE INHIBITOR FOR HYPOXIC-ISCHEMIC NEW BORN BRAIN DAMAGE  

PubMed Central

Agmatine is an endogenous brain metabolite, decarboxylated arginine, which has neuroprotective properties when injected intraperitoneally (i.p.) into rat pups following hypoxic-ischemia. A previous screen for compounds based on rat brain lysates containing agmatinase with assistance from computational chemistry, led to piperazine-1-carboxamidine as a putative agmatinase inhibitor. Herein, the neuroprotective properties of piperazine-1-carboxamidine are described both in vitro and in vivo. Organotypic entorhinal-hippocampal slices were firstly prepared from seven-day-old rat pups and exposed in vitro to atmospheric oxygen depletion for 3 hrs. Upon reoxygenation the slices were treated with piperazine-1-carboxamidine or agmatine (50 ?g/ml agents), or saline, and 15 hours later propidium iodine was used to stain. Piperazine-1-carboxamidine or agmatine produced substantial in vitro protection compared to post-reoxygenated saline-treated controls. An in vivo model involved surgical right carotid ligation followed by exposure to hypoxic ischemia (8% oxygen) for 2.5 hours. Piperazine-1-carboxamidine at 50 mg/kg i.p. was given 15 minutes post-reoxygenation and continued twice daily for 3 days. Cortical agmatine levels were elevated (+28.5%) following piperazine-1-carboxamidine treatment with no change in arginine or its other major metabolites. Histological staining with anti-Neun monoclonal antibody also revealed neuroprotection of CA1–3 layers of the hippocampus. Until endpoint at 22 days of age, no adverse events were observed in treated pups' body weights, rectal temperatures, or prompted ambulation. Piperazine-1-carboxamidine therefore appears to be a neuroprotective agent of a new category, agmatinase inhibitor. PMID:23334804

Piletz, John E.; Klenotich, Stephanie; Lee, Ken S.; Zhu, Qian Long; Valente, Edward; Collins, Michael A.; Jones, Vyvyca; Lee, Soeb Nam; Yangzheng, Feng

2013-01-01

221

1-Piperonylpiperazinium 4-chloro-benzoate  

PubMed Central

In the title salt {systematic name: 1-[(1,3-benzodioxol-5-yl)meth­yl]piperazin-1-ium 4-chloro­benzoate}, C12H17N2O2 +·C7H4ClO2 ?, the piperazine ring adopts a slightly disordered chair conformation. The dioxole ring is in a flattened envelope conformation with the methyl­ene C atom forming the flap. The relative orientation of the piperonyl ring system and the piperazine rings is reflected in the N—C—C C torsion angle of 132.3?(1)°. In the anion, the mean plane of the carboxyl­ate group is twisted from that of the benzene ring by 14.8?(9)°. In the crystal, the components are linked by N—H?O and weak C—H?O hydrogen bonds, forming chains along [010]. PMID:24764993

Kavitha, Channappa N.; Kaur, Manpreet; Anderson, Brian J.; Jasinski, Jerry P.; Yathirajan, H. S.

2014-01-01

222

Mutagenicity of products generated by the reaction between several antiparasitic drugs and nitrite  

SciTech Connect

Drugs containing secondary aliphatic amines, heterocyclic nitrogen, or secondary aliphatic amido groups (chloroquine, dehydroemetine, mebendazole, and piperazine) and pyrimidine derivatives such as pyrantel pamoate were reacted in vitro with sodium nitrite at pH 3.7 and became mutagenic for Salmonella typhimurium strain TA1535. The products derived from the nitrosation of chloroquine and dehydroemetine required metabolic activation by mammalian hepatic S9 to be mutagenic. The N-nitroso derivatives of mebendazole, piperazine, and pyrantel pamoate were mutagenic with and without S9, although more activity was noted in the presence of S9 with the nitrosated compounds formed from mebendazole and piperazine. Under identical conditions, no mutagenic products were detected from quaternary ammonium salts such as bephenium hydroxynaphthoate or drugs containing tertiary heterocyclic amino groups, such as iodochlorhydroxyquin.

Alba, M.A.; Espinose, J.; Cortinas de Nava, C.

1988-01-01

223

Effect of piribedil and its metabolite, S584, on brain lipid peroxidation in vitro and in vivo  

Microsoft Academic Search

We studied the effect of piribedil (1-3,4-methylendioxybenzyl-4-(2-pyrimidyl) piperazine) and its catechol metabolite, S584 (1-(3,4-dihydroxybenzyl-4-(2-pyrimidinyl)-piperazine), on rat brain lipid peroxidation (a) in vitro in rat synaptosomes and cortical slices after induction of an oxidative stress and (b) in vivo in mouse brain after short-term exposure (two and three 4-h cycles) to O2\\/CO2 (95%:5%). The metabolite (10?4–10?5 M), but not piribedil, prevented

Federico Calzi; Raffaele Bellasio; Giovanna Guiso; Silvio Caccia; Maria Teresa Tacconi

1997-01-01

224

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Progress has been made in this reporting period on three subtasks. The rigorous Electrolyte Non-Random Two-Liquid (electrolyte-NRTL) model has been regressed to represent CO{sub 2} solubility in potassium carbonate/bicarbonate solutions. An analytical method for piperazine has been developed using a gas chromatograph. Funding has been obtained and equipment has been donated to provide for modifications of the existing pilot plant system with stainless steel materials.

Gary T. Rochelle; A. Frank Seibert; J. Tim Cullinane; Terraun Jones

2003-01-01

225

Quantitative determination of amoxicillin and its decomposition products by high-performance liquid chromatography.  

PubMed

Amoxicillin, amoxicilloates, amoxicillin oligomers and amoxicillin piperazine-2,5-dione are separated by reversed-phase (C8) high-performance liquid chromatography with gradient elution. Quantitative results are reported for a number of samples. Amoxicillin trihydrate samples mostly contain amoxicilloate as the main impurity. Samples of the sodium salt also contain the piperazine-2,5-dione and the dimer. Higher oligomers such as the trimer and tetramer were not present in significant amounts. Several samples were also analysed by a mercurimetric titration method. PMID:3988846

De Pourcq, P; Hoebus, J; Roets, E; Hoogmartens, J; Vanderhaeghe, H

1985-03-15

226

LC determination and purity evaluation of nefazodone HCl in bulk drug and pharmaceutical formulations  

Microsoft Academic Search

A simple, selective and reproducible reversed-phase liquid chromatography (LC) method has been developed for the quantitative determination of nefazodone hydrochloride (I) in the presence of its related impurities, namely 5-ethyl-4-(2-phenoxyethyl)-2H-1,2,4-triazol-3-(4H)one (II), 1-(3-chlorophenyl)-4-(3-chloropropyl) piperazine hydrochloride (III) and 1,11-trimethylene-bis[4-(3-chlorophenyl) piperazine] hydrochloride (IV). The separation was achieved using an Inertsil ODS-3V (250×4.6 mm2) column and a mobile phase comprising 0.05 M KH2PO4 (pH

D Sreenivas Rao; S Geetha; M. K Srinivasu; G Om Reddy

2001-01-01

227

Possible pharmacokinetic and pharmacodynamic factors affecting parkinsonism inducement by cinnarizine and flunarizine  

Microsoft Academic Search

Potentialities of cinnarizine [1-(diphenylmethyl)-4-(3-phenyl-2-propenyl)piperazine, CZ] and its fluorine derivative flunarizine [1-[bis(4-fluorophenyl)-methyl]-4-(3-phenyl-2-propenyl)piperazine, FZ] to induce parkinsonism as an adverse effect were evaluated pharmacokinetically and pharmacodynamically in rats. In multiple-dose experiments, CZ or FZ was given to rats at a daily dose of 20 ?mol\\/kg for 1, 5, 10, 15, and 30 days, and CZ, FZ, and the ring-hydroxylated metabolites of their

Satoru Kariya; Sadao Isozaki; Yasuhiro Masubuchi; Tokuji Suzuki; Shizuo Narimatsu

1995-01-01

228

Simultaneous determination of amphetamine and its analogs in human whole blood by gas chromatography-mass spectrometry.  

PubMed

A sensitive and specific gas chromatography-mass spectrometry (GC-MS) method for the determination of amphetamine (AM), methamphetamine (MA), methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA) and methylenedioxyethylamphetamine (MDEA) in whole blood was designed, using the respective pentadeuterated analogs of the analytes as internal standards (I.S.). After alkalinisation of blood samples, the amphetamines were extracted using diethyl ether, derivatized with heptafluorobutyric anhydride, then purified by successive washings with deionized water and 4% NH4OH. Extraction recoveries were 85.2% for AM, 90.9% for MA, 76.5% for MDA, 84.1% for MDMA and 63.6% for MDEA. Chromatographic separation was performed on a non-polar 30 m x 0.32 mm HP 5 MS capillary column using a temperature program. Detection was carried out in the electron-impact, selected ion-monitoring mode, using three mass-to-charge ratios for each analyte and one for each I.S. Limits of detection ranged from 0.5 to 8 ng/ml and limits of quantification were 10 ng/ml for AM, MDMA and MDEA; 20 ng/ml for MA; and 50 ng/ml for MDA. The method was linear from this limit up to 1000 ng/ml for all analytes, with good intra-assay precision and good intermediate precision and accuracy over these ranges. There was no interferences from other sympathomimetic drugs such as ephedrine, norephedrine or methoxyphenamine. This method is thus suitable for clinical and forensic toxicology, as well as for doping control. PMID:9390716

Marquet, P; Lacassie, E; Battu, C; Faubert, H; Lachâtre, G

1997-10-24

229

The SULFTEN system commercial experience with a new tail gas treating technology  

SciTech Connect

The SULFTEN system is a tail gas reduction process which offers low emissions and high energy savings, while retaining the ease of operation of a typical amine based tail gas treating unit. The system is capable of reducing the vent gas H/sub 2/S concentration to less than 10ppmv. The system is highly selective, increasing the CO/sub 2/ slip. It is based on a proprietary MDEA based solvent with none of the disadvantages of more complicated TGTUs. Actual operating experience at Champlin Petroleum Company's Corpus Christi, Texas Refinery confirmed the validity of the above performance and savings. An attractive payout of approximately one year is realized.

Tragitt, G.N.; Armstrong, T.R.; Bourdon, J.C.; Sigmund, P.W.

1985-03-01

230

Proceedings of the gas conditioning conference, 1981  

SciTech Connect

This volume contains proceedings of 10 papers delivered at the meeting. The following subjects are covered: operating data from a commercial MDEA gas treater; oxygen use in Claus sulfur plants; different approaches to solving gas treating problems; gas sweetening in Saudi Arabia in large DGA plants; methanol injection and recovery in a large turboexpander plant; use of methanol for hydrate control in expander plants; natural gas dehydration; use of methanol in an acid gas removal solvent in coal gasification processes; ways to avoid excessive glycol related costs in the operation of gas dehydrators; Claus tail gas cleanup. Some papers are accompanied by bibliographical citations. Each contribution is abstracted and indexed separately.

Not Available

1981-01-01

231

Preparation and investigation of separation properties of polyethersulfone supported poly(piperazineamide) nanofiltration membrane using microwave-assisted polymerization  

Microsoft Academic Search

The effect of microwave irradiation on preparation of composite nanofiltration membranes was investigated. Interfacial polymerization technique was employed by applying trimesoyl chloride (TMC) and piperazine (PIP) as the reagents for preparation of polyamide (PA) skin layer on a polyethersulfone (PES) support. The different times (0, 10, 30 and 60s) and powers (540, 720 and 900W) of microwave irradiation were applied.

Y. Mansourpanah; S. S. Madaeni; A. Rahimpour

2009-01-01

232

Published: March 23, 2011 r 2011 American Chemical Society 428 dx.doi.org/10.1021/ml200008b |ACS Med. Chem. Lett. 2011, 2, 428432  

E-print Network

allosamidin,23 and piperazine derivatives.24 Most of these compounds are natural products or their derivatives, and their use for either in vivo studies or as ligand design leads is significantly impeded by their limited chitinase inhibitor comprised of two linked caffeine molecules with desirable druglike properties

van Aalten, Daan

233

Intramolecular Pd(II)-Catalyzed Aerobic Oxidative Amination of Alkenes: Synthesis of Six-Membered N-Heterocycles  

PubMed Central

Use of a base-free Pd(DMSO)2(TFA)2 catalyst system enables the synthesis of six-membered nitrogen heterocycles via a Wacker-type aerobic oxidative cyclization of alkenes bearing tethered sulfonamides. Various heterocycles, including morpholines, piperidines, piperazines, and piperazinones are accessible by this method. PMID:22356620

Lu, Zhan; Stahl, Shannon S.

2012-01-01

234

Libraries from Libraries: A Series of Sulfonamide Linked Heterocycles Derived from the Same Scaffold  

PubMed Central

A libraries from libraries approach is described for the synthesis of five different sulfonamide linked scaffolds. Four of the scaffolds are sulfonamides linked to heterocycles; piperazine, thiourea, cyclic guanidine, and dimethyl cyclic guanidine. The fifth scaffold is a polyamine linked sulfonamide. Three different diversity positions were effectively incorporated into each scaffold providing a number of different compounds with good yields and purity. PMID:24363466

Debevec, Ginamarie; Chen, Wenteng; Yu, Yongping; Houghten, Richard A.; Giulianotti, Marc A.

2013-01-01

235

Water Research 38 (2004) 24992504 Modeling the sorption kinetics of divalent metal  

E-print Network

Water Research 38 (2004) 2499­2504 Modeling the sorption kinetics of divalent metal ions in revised form 13 February 2004; accepted 5 March 2004 Abstract The sorption kinetics of the divalent metals/sorbent ratios (from 1.67 to 3.33 mol sorbate/mol sorption sites) in 10 mM Na-piperazine N; N0 -bis 2- ethane

Roden, Eric E.

236

General acteoside of Rehmanniae leaves in the treatment of primary chronic glomerulonephritis: a randomized controlled trial.  

PubMed

The objective of the study was to investigate the effectiveness and efficacy of the randomized, parallel, and controlled trial of Traditional Chinese Medicine, general acteoside of Rehmanniae leaves, compared with piperazine ferulate in the treatment of primary chronic glomerulonephritis. Rehmanniae leaves and piperazine ferulate can reduce proteinuria and erythrocyturia effectively in the treatment of primary chronic glomerulonephritis. A total of 400 patients diagnosed with primary chronic glomerulonephritis were recruited from outpatient clinics and were randomly assigned to the treatment group (general acteoside of Rehmanniae leaves, two 200mg tablets, bid) or the control group (piperazine ferulate, four 50-mg tablets, bid ). The primary outcome was 24-h urinary protein. Secondary outcome measures included estimated glomerular filtration rate (eGFR), erythrocyturia, and electrolytes. After 8 weeks of treatment, the treatment group and the control group showed a mean reduction in 24-h proteinuria of 34.81% and 37.66%. The 95% CI of difference of the mean reduction in 24-h proteinuria between the two groups was [-11.50%, 5.80%]. No significant differences were found between the two groups in the erythrocyturia reduction. Neither group showed obvious changes between baseline and 8 weeks in eGFR or electrolytes. Adverse events occurred at a similarly low rate in the treatment group (1.5%) and control group (2.5%, P = 0.7238). Both general acteoside of Rehmanniae leaves and piperazine ferulate can reduce proteinuria and erythrocyturia effectively in the treatment of primary chronic glomerulonephritis. PMID:24146510

Qiu, HongYu; Fan, WenXing; Fu, Ping; Zuo, Chuan; Feng, Ping; Liu, Fang; Zhou, Li; Chen, Feng; Zhong, Hui; Liang, YaPing; Shi, Mei

2013-01-01

237

Molecular Structure of Piperazinomycin  

NSDL National Science Digital Library

Piperazinomycin is a naturally occuring macrocylic piperazine. This natural product is colorless and insoluble in water and was isolated from the bacterium streptovercillium olivoreticulis. This metabolite possesses antimicrobial, antifungal as well as antibiotic properties. Piperazinomycin can be synthesized by a bacteria of the streptovercillium genus.

2003-04-11

238

Oxidation products of amines in CO2 capture Andrew Sexton, Gary T. Rochelle*  

E-print Network

inhibitor A is not present; glycolate is most prevalent when proprietary inhibitor A is added to MEA is much slower than the rate of piperazine degradation; this suggests inhibitor A is an effective degradation inhibitor. The quantification of these degradation products and the oxygen stoichiometry

Rochelle, Gary T.

239

1Mem Inst Oswaldo Cruz, Rio de Janeiro, Vol. 98: 000-000, 2003 8-Methoxy-naphtho[2,3-b]thiophen-4,9-quinone, a  

E-print Network

share a defence mechanism against oxidative stress based on the dithiol trypanothione [N1,N8-bis or empiric approaches, different classes of compounds, including peptides and peptoid, substituted polyamines piperazines and nitrofuran derivatives, were studied for their inhibitory potential (see reviews by Werbovetz

Schnaufer, Achim

240

Adsorption and desorption of atrazine on a melamine-based soil amendment  

E-print Network

Adsorption kinetics and adsorption-desorption of atrazine on organoclay composites prepared with the surfactant 6-piperazin-1-yl-N,N'-bis-(1,1,3,3-tetramethyl-butyl)-(1,3,5)triazine-2,4-diamine and Houston Black clay were studied using the indirect...

Neitsch, Susan Lynn

2004-09-30

241

Dipeptidyl peptidase-4 inhibitor with ?-amino amide scaffold: synthesis, SAR and biological evaluation.  

PubMed

Inhibitors of dipeptidyl peptidase-4 (DPP4) have been shown to be effective treatments for type 2 diabetes. Several series of ?-amino amide containing piperazine derivatives have been prepared and evaluated as a inhibitor of DPP4. Finally compound 5m was selected for further evaluation. PMID:22850208

Kim, Heung Jae; Kwak, Woo Young; Min, Jong Pil; Sung, Si Young; Kim, Ha Dong; Kim, Mi Kyung; Kim, Hae Sun; Park, Kyung Jin; Son, Moon Ho; Kim, Soon Hoe; Lee, Bong Jin

2012-09-01

242

The Effect of the Adsorption of Multicharge Cations on the Selectivity of a Nanofiltration Membrane  

Microsoft Academic Search

The selective and electrokinetic properties of an OPMN-KMZ nanofiltration membrane with a selective layer of piperazine and trimesoyl chloride copolymer with respect to aqueous solutions of barium, yttrium, and thorium nitrates are investigated in a wide range of their concentrations. It is disclosed that, after the charge reversal of the initially negatively charged surface of this membrane by thorium cations,

K. G. Sabbatovskii

2003-01-01

243

pubs.acs.org/jmc Published on Web 11/11/2010 r 2010 American Chemical Society 8376 J. Med. Chem. 2010, 53, 83768386  

E-print Network

pubs.acs.org/jmc Published on Web 11/11/2010 r 2010 American Chemical Society 8376 J. Med. Chem retaining high potency. The SAR studies revealed that the meta- or para-substituted phenyl spacer and N4 -acetyl or sulfonyl substituted piperazine were optimal structures for achieving high potency and good

Hammock, Bruce D.

244

Use of anthelmintics in herbivores and evaluationof risks for the non target fauna of pastures  

Microsoft Academic Search

The overall purpose of this paper was to review the major and most recent literature relat- ing the effects of anthelmintics on dung breeding invertebrates and dung degradation. Faecal residues or metabolites of drugs belonging to the benzimidazole and levamisole\\/morantel groups are relatively harmless to dung fauna, on the contrary to other anthelmintics such as coumaphos, dichlorvos, pheno- thiazine, piperazine,

Jean-Pierre Lumaret; Faiek Errouissi

2002-01-01

245

CO2 Capture by Absorption with Potassium Carbonate  

E-print Network

corrosion rate in 5 M MEA/1.2M PZ is 22 mpy. With 1 wt% heat stable salt, the corrosion rate increases by 50 solution increases significantly with CO2 loading and decreases with MEA concentration. The base case absorber. The oxidative degradation of piperazine or organic acids is reduced significantly by inhibitor A

Rochelle, Gary T.

246

ORIGINAL ARTICLE The interaction of zinc with membrane-associated 18.5 kDa  

E-print Network

of polar and charged amino acids, and has an adaptive conformation depending on its environment and binding HEPES N-(2-Hydroxyethyl) piperazine-N0 -2- ethanesulfonic acid HPLC High-performance liquid. Dutcher Department of Physics, University of Guelph, Guelph, ON N1G 2W1, Canada 123 Amino Acids (2010) 39

Dutcher, John

247

Optical Properties of Acrylate-Based Negative-Type Photoresist and Its Application to Optical Waveguide Fabrication  

NASA Astrophysics Data System (ADS)

In this article, we present some of the optical properties of a polymeric acrylate-based photoresist material called PNME, by its principal components, which are pentaerythritol triacrylate, n-methyldiethanolamine, and eosin. The refractive index and absorption spectra were measured. Because of the low absorption of PNME in the datacom and telecom regions, PNME was studied with respect to its suitability for the fabrication of a channel waveguide and/or an optical fiber. A multimode optical waveguide was fabricated using a cold UV stamping fabrication method, and propagation losses at 1.3 ?m were measured. An optical fiber core was fabricated using a light-induced self-writing fabrication method. In our study, it was found that optical waveguides made from PNME have low propagation losses due to smooth sidewalls and the low absorption of PNME. An optical waveguide with a corrugated core was also fabricated.

Gustafik, Pavol; Sugihara, Okihiro; Okamoto, Naomichi

2004-04-01

248

Routine analysis of amphetamine class drugs as their naphthaquinone derivatives in human urine by high-performance liquid chromatography.  

PubMed

We describe a simple HPLC method which is suitable for the routine confirmation of immunoassay positive amphetamine urine samples. The precolumn derivisation method employing sodium naphthaquinone-4-sulphonate was found to have adequate sensitivity, selectivity and precision for the measurement of amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxyethylamphetamine (MDEA) at 500 microg/l cutoff level for confirmatory analysis of amphetamines in urine. The specificity of the method is enhanced by detecting the peaks at two different wavelengths. The ratios of the peak heights measured at the two wavelengths were different for each of the 5 amphetamines analysed. There was no interference from other phenylethylamine analogues that are commonly found in "over the counter" preparations. The HPLC method is compared to a commercial TLC system for detecting amphetamines in urine of drug abusers attending drug rehabilitation programmes. The HPLC confirmatory method described is a viable alternative to GC or to the more complex and costly GC-MS techniques for confirming amphetamine, methamphetamine, MDMA, MDA and MDEA in urine of drug abusers especially when used in a clinical care setting. PMID:10670737

Talwar, D; Watson, I D; Stewart, M J

1999-12-10

249

'Catalysts' for polyacrylamide gel polymerization and detection of proteins by silver staining.  

PubMed

The crosslinker diacrylyl-piperazine produces polyacrylamide gels which display improved electrophoretic separation of proteins and better physical strength. It also produces gels with improved detection of proteins by ammoniacal silver staining by reducing the background. This reduced background provided us with an opportunity to investigate residual background staining caused by the catalytic reagents utilized in the polymerization of acrylamide gels. The commonly used catalyst system, tetramethyl-ethylenediamine and ammonium persulfate was shown to be responsible for the yellow staining background found after a prolonged development time with silver staining. An alternate catalyst system has been designed to decrease further the formation of this background staining. Dimethyl-piperazine or tetramethylethylenediamine, potassium or ammonium persulfate, and sodium thiosulfate are shown to provide for gels which have excellent mechanical and staining characteristics. These catalytic systems produce little background staining despite prolonged development time with the ammoniacal silver stain, and they reduce background staining with the dichromate silver stain. PMID:2484987

Hochstrasser, D F; Merril, C R

1988-01-01

250

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. CO{sub 2} mass transfer rates are second order in piperazine concentration and increase with ionic strength. Modeling of stripper performance suggests that 5 m K{sup +}/2.5 m PZ will require 25 to 46% less heat than 7 m MEA. The first pilot plant campaign was completed on June 24. The CO{sub 2} penetration through the absorber with 20 feet of Flexipac{trademark} 1Y varied from 0.6 to 16% as the inlet CO{sub 2} varied from 3 to 12% CO{sub 2} and the gas rate varied from 0.5 to 3 kg/m{sup 2}-s.

Gary T. Rochelle; Eric Chen; J.Tim Cullinane; Marcus Hilliard; Jennifer Lu; Babatunde Oyenekan; Ross Dugas

2004-07-29

251

CO{sub 2} CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Thermodynamic modeling predicts that the heat of desorption of CO{sub 2} from 5m K+/2.5 PZ from 85 kJ/mole at 40 C to 30 kJ/mole at 120 C. Mass transfer modeling of this solvent suggests that carbonate and general salt concentration play a major role in catalyzing the rate of reaction of CO{sub 2} with piperazine. Stripper modeling suggests that with the multipressure stripper, the energy consumption with a generic solvent decreases by 15% as the heat of desorption is decreased from 23.8 to 18.5 kcal/gmol. A second pilot plant campaign with 5m K+/2.5 PZ was successfully completed.

Gary T. Rochelle; J.Tim Cullinane; Marcus Hilliard; Eric Chen; Babatunde Oyenekan; Ross Dugas

2005-01-31

252

Antitumor Activity of Bis-Indole Derivatives  

PubMed Central

This paper reports the synthesis of compounds formed by two indole systems separated by a heterocycle (pyridine or piperazine). As a primary screening, the new compounds were submitted to the National Cancer Institute for evaluation of antitumor activity in the human cell line screen. The pyridine derivatives were far more active than the piperazine derivatives. For the study of the mechanism of action, the most active compounds were subjected to COMPARE analysis and to further biological tests including proteasome inhibition and inhibition of plasma membrane electron transport. The compound bearing the 5-methoxy-2-indolinone moiety was subjected to the first in vivo experiment (hollow fiber assay) and was active. It was therefore selected for the second in vivo experiment (human tumor xenograft in mice). In conclusion we demonstrated that this approach was successful since some of the compounds described are much more active than the numerous, so far prepared and tested 3-indolylmethylene-2-indolinones. PMID:18598018

Andreani, Aldo; Burnelli, Silvia; Granaiola, Massimiliano; Leoni, Alberto; Locatelli, Alessandra; Morigi, Rita; Rambaldi, Mirella; Varoli, Lucilla; Landi, Laura; Prata, Cecilia; Berridge, Michael V.; Grasso, Carole; Fiebig, Heinz-Herbert; Kelter, Gerhard; Burger, Angelika M.; Kunkel, Mark W.

2009-01-01

253

Nitroimidazoles. V. Synthesis and anti-HIV evaluation of new 5-substituted piperazinyl-4-nitroimidazole derivatives.  

PubMed

A series of 2-alkylthio-1-[4-(1-benzyl-2-ethyl-4-nitro-1H- -imidazol-5-yl)-piperazin-1-yl]ethanones (3-9) and alkyl-[4-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-yl)-piperazin-1-yl)ketones (11-20) as well as the indole analogue 22 were synthesized from 4-nitro-5-piperazinyl imidazole derivative 1, with the aim to develop newly non-nucleoside reverse transcriptase inhibitors (NNRTIs). The newly synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compound 4 showed inhibition of HIV-1 (EC50 0.45 microg mL-1) and HIV-2 (0.50 microg mL-1), while 11 showed inhibition of HIV-1 (EC50 2.48 microg mL-1, SI = 4). PMID:18165184

Al-Soud, Yaseen A; Al-Masoudi, Najim A; Hassan, Hamed Gh; De Clercq, Erik; Pannecouque, Christophe

2007-12-01

254

Nitroimidazoles Part 6. Synthesis, structure and in vitro anti-HIV activity of new 5-substituted piperazinyl-4-nitroimidazole derivatives.  

PubMed

2-Amino-1-[4-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-yl)piperazin-1-yl]ethanone [6] was prepared from 1-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-yl) piperazine [3]. A series of new 2-oxoethyl-arylamide [9,10] and 2-oxoethyl-arylsulphonamide [11-14] derivatives were synthesized from [6] with the aim of developing new non-nucleoside reverse transcriptase inhibitors. Alternatively, the amine [17] was synthesized from [3] via the phthalimide derivative [16]. The arylsulphonamide derivatives [18-23] and the arylamide analogues [24-26] were synthesized from [17]. The compounds were evaluated for their anti-HIV-1 and anti-HIV-2 activity in MT-4 cells. PMID:17907377

Al-Masoudi, Najim A; Al-Soud, Yaseen A; De Clercq, Erik; Pannecouque, Christophe

2007-01-01

255

CO2 Capture by Absorption with Potassium Carbonate  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The final campaign of the pilot plant was completed in February 2006 with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ using Flexipac AQ Style 20. The new cross-exchanger reduced the approach temperature to less than 9 C. Stripper modeling has demonstrated that a configuration with a ''Flashing Feed'' requires 6% less work that a simple stripper. The oxidative degradation of piperazine proceeds more slowly than that of monoethanolamine and produces ethylenediamine and other products. Uninhibited 5 m KHCO{sub 3}/2.5 m PZ corrodes 5 to 6 times faster that 30% MEA with 0.2 mol CO{sub 2}/mol MEA.

Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Amorvadee Veawab

2006-04-28

256

Cinnarizinium fumarate  

PubMed Central

In the title salt {systematic name: 4-diphenyl­methyl-1-[(E)-3-phenyl­prop-2-en-1-yl]piperazin-1-ium (2Z)-3-carb­oxy­prop-2-enoate}, C26H29N2 +·C4H3O4 ?, the piperazine ring in the cation adopts a distorted chair conformation and contains a positively charged N atom with quaternary character. The dihedral angle between the mean planes of the phenyl rings of the diphenyl­methyl group is 74.2?(7)° and those between these rings and the phenyl ring of the 3-phenyl­prop-2-en-1-yl group are 12.7?(9) and 80.6?(8)°. In the crystal, N—H?O and O—H?O hydrogen bonds form chains along [001]. Weak C—H?O inter­actions connect parallel chains along [010], forming layers perpendicular to the a-axis direction. PMID:23476398

Kavitha, C. N.; Yildirim, Sema Ozturk; Jasinski, Jerry P.; Yathirajan, H. S.; Butcher, Ray J.

2013-01-01

257

A Valence Bond Description of Dizwitterionic Dithiolene Character in an Oxomolybdenum-bis(dithione)  

PubMed Central

Metallo-dithiolene non-innocence is explored in an oxomolybdenum-bis(dithione) complex, [Mo4+O(i-Pr2Pipdt)2Cl][PF6] (where i-Pr2Pipdt is N,N’-piperazine-2,3-dithione), that possesses a piperazine ring as an integral part of the dithiolene ligand. The title complex displays unusual spectroscopic features for a formally reduced Mo(IV) dithiolene complex, namely a low energy metal-to-ligand charge transfer band with appreciable intensity and C-C and C-S stretching frequencies that are markedly different from those of oxomolydenum complexes coordinated to dianionic dithiolene ligands. The electronic structure of the ligand has been described in valence bond terms as a resonance hybrid of dithione and dizwitterionic dithiolene contributing structures. PMID:23956683

Mtei, Regina P.; Perera, Eranda; Mogesa, Benjamin; Stein, Benjamin; Basu, Partha; Kirk, Martin L.

2013-01-01

258

Integration of GC/EI-MS and GC/NCI-MS for simultaneous quantitative determination of opiates, amphetamines, MDMA, ketamine, and metabolites in human hair.  

PubMed

In this paper, the possibility of using a multiple ionization mode approach of GC/MS was developed for the simultaneous hair testing of common drugs of abuse in Asia, including amphetamines (amphetamine, AP; methamphetamine, MA; methylenedioxy amphetamine, MDA; methylenedioxy methamphetamine, MDMA; methylenedioxy ethylamphetamine, MDEA), ketamine (ketamine, K; norketamine, NK), and opiates (morphine, MOR; codeine, COD; 6-acetylmorphine, 6-AM). This strategy integrated the characteristics of gas chromatography-mass spectrometry (GC-MS) using electron impact ionization (EI) and negative chemical ionization (NCI). Hair samples (25 mg) were washed, cut, and incubated overnight at 25 degrees C in methanol-trifluoroacetic acid (methanol-TFA). The samples were extracted by solid phase extraction (SPE) procedure, derivatized using heptafluorobutyric acid anhydride (HFBA) at 70 degrees C for 30 min, and the derivatives analyzed by GC-MS with EI and NCI. The limit of detection (LOD) with GC/EI-MS analysis obtained were 0.03 ng/mg for AP, MA, MDA, MDMA, and MDEA; 0.05 ng/mg for K, NK, MOR, and COD; and 0.08 ng/mg for 6-AM. The LOD of GC/NCI-MS analysis was much lower than GC/EI-MS analysis. The LOD obtained were 30 pg/mg for AP and MDA in GC/EI-MS and 2 pg/mg in GC/NCI-MS. Therefore, the sensitivity of AP and MDA in GC/NCI-MS was improved from 15-fold compared with EI. The sensitivity of AP, MA, MDA, MDMA, MDEA, MOR, and COD was improved from 15- to 60-fold compared with EI. In addition, the sensitivity of 6-AM increased 8-fold through selection of m/z 197 for the quantitative ion. Moreover, K and NK could dramatically improve their sensitivity at 200- and 2000-fold. The integration of GC/EI-MS and GC/NCI-MS can obtain the high sensitivity and complementary results of drugs of abuse in hair. Six hair samples from known drug abusers were examined by this new strategy. These results show that integrating the characteristics of GC/EI-MS and GC/NCI-MS were not only enhancement of the sensitivity but also avoid wrong results and wrong interpretations of correct results. PMID:18585989

Wu, Ya-Hsueh; Lin, Keh-Liang; Chen, Su-Chin; Chang, Yan-Zin

2008-07-15

259

Cyclooctadepsipeptides—an anthelmintically active class of compounds exhibiting a novel mode of action  

Microsoft Academic Search

There are three major classes of anthelmintics for veterinary use: the benzimidazoles\\/prebenzimidazoles, the tetrahydropyrimidines\\/imidazothiazoles, and the macrocyclic lactones. In nematodes, there are five targets for the existing anthelmintics: the nicotinergic acetylcholine receptor which is the target of tetrahydropyrimidines\\/imidazothiazoles and indirectly that of the acetylcholineesterase inhibitors; the GABA receptor which is the target of piperazine, the glutamate-gated chloride channel as the

Achim Harder; Hans-Peter Schmitt-Wrede; Jürgen Krücken; Predrag Marinovski; Frank Wunderlich; James Willson; Kiran Amliwala; Lindy Holden-Dye; Robert Walker

2003-01-01

260

Structure-Related Inhibitory Effect of Antimicrobial Enoxacin and Derivatives on Theophylline Metabolism by Rat Liver Microsomes  

Microsoft Academic Search

Enoxacin, an antimicrobial fluoroquinolone with a 7-piperazinyl-1,8-naphthyridine skeleton, is a potent inhibitor of cytochrome P-450-mediated theophylline metabolism. The present study was designed to clarify, using seven enoxacin derivatives, the molecular characteristics of the fluoroquinolone responsible for the inhibition. Three derivatives with methyl-substituted 7-piperazine rings inhibited rat liver microsomal the- ophylline metabolism to 1,3-dimethyluric acid to an extent similar to that

YASUYUKI MIZUKI; IWAO FUJIWARA; TOSHIKAZU YAMAGUCHI; ANDYUTAKA SEKINE

1996-01-01

261

5HT 1C receptor antagonists have anxiolytic-like actions in the rat social interaction model  

Microsoft Academic Search

The effects of a range of 5-HT receptor antagonists were examined in an animal model of anxiety — the social interaction test. Six antagonists with high affinity for 5-HT1C receptors; mianserin, (+) mianserin, 1-naphthyl piperazine, ICI 169 369, pizotifen and LY 53857 all increased the time spent in active social interaction by pairs of weight-matched rats under high light unfamiliar

G. A. Kennett

1992-01-01

262

Stimulation of a dopamine-sensitive adenylate cyclase in homogenates of rat striatum by a metabolite of piribedil (ET 495)  

Microsoft Academic Search

The addition of dopamine (1–100µM) to homogenates of rat striatum incubated with ATP evoked a 120% increase in the rate of cyclic 3'5' adenosine monophosphate (cyclic AMP) production. The effects of added dopamine were mimicked by the addition of the compound S 584 [1-3,4-(dihydroxybenzyl)-4-(2-pyrimidinyl) piperazine] (1–100 µM), a catechol metabolite of the dopaminergic stimulant drug piribedil (ET 495). The latter

R. J. Miller; L. L. Iversen

1974-01-01

263

Synthesis, properties and supramolecular structure of piperazinediium thiosulfate monohydrate +  

Microsoft Academic Search

Aqueous reaction of ammonium thiosulfate with piperazine (pip) results in the formation of the title compound (pipH2)[S2O3]?H2O 1 (pipH2 = piperazinediium) in good yield. 1 was characterized by elemental analysis, IR, Raman and NMR spectra, X-ray powder pattern and its structure was determined.\\u000a On heating at 100°C, 1 transforms to anhydrous piperazinediium thiosulfate 2, which can be rehydrated to the

Bikshandarkoil R Srinivasan; Ashish R Naik; Sunder N Dhuri; Christian Näther; Wolfgang Bensch

264

Modification of Marine Natural Product Ningalin B and SAR Study Lead to Potent P-Glycoprotein Inhibitors.  

PubMed

In this study, new marine ningalin B analogues containing a piperazine or a benzoloxy group at ring C have been synthesized and evaluated on their P-gp modulating activity in human breast cancer and leukemia cell lines. Their structure-activity relationship was preliminarily studied. Compounds 19 and 20 are potent P-gp inhibitors. These two synthetic analogues of permethyl ningalin B may be potentially used as effective modulators of P-gp-mediated drug resistance in cancer cells. PMID:25329704

Yang, Chao; Wong, Iris L K; Jin, Wen Bin; Jiang, Tao; Chow, Larry M C; Wan, Sheng Biao

2014-01-01

265

Characterization of metal corrosion by aqueous amino acid salts for the capture of CO 2  

Microsoft Academic Search

We investigated the absorption ability of potassium salts of amino acid solutions for carbon dioxide and compared the results\\u000a with MEA. The corrosion and degradation behavior were investigated in a CO2 absorption process using aqueous potassium salts of glycine and taurine. The experimental parameters varied were the concentration,\\u000a amino acid type, temperature, CO2 loading, piperazine, and the presence of corrosion

Seongyeon Ahn; Ho-Jun Song; Jin-Won Park; Ji Hyun Lee; In Young Lee; Kyung-Ryong Jang

2010-01-01

266

On the nature of boron-carbon-nitrogen compounds synthesised from organic precursors  

Microsoft Academic Search

Three compounds were prepared through pyrolysis of organic precursors, namely pyridine-borane, piperazine-borane, poly(acrylonitrile)-BCl3, following the routes proposed in the literature for the synthesis of single-phase boron carbonitrides of various compositions. X-ray diffraction and MAS NMR studies performed on the powders obtained suggest that the resulting compounds are mixtures of amorphous boron and turbostratically distorted hexagonal boron nitride and graphite rather

Yuri G. Andreev; Torsten Lundström; Robin K. Harris; Se-Woung Oh; David C. Apperley; Derek P. Thompson

1995-01-01

267

Synthesis of some 2,3-disubstituted quinazolones as possible anticonvulsants.  

PubMed

By the condensation of 2-phenyl-3-acylchloride quinazolin (3H)-4-one with N-phenyl- and N-methyl piperazines or piperidine, 15 new 2-phenyl-3-piperidino/substituted piperazino acyl-quinazolin (3H)-4-ones 1--3 have been prepared. All the compounds barring one exhibited at the 100 mg/kg dose level significant activity against pentylenetetrazol induced seizures but these compounds did not afford any protection against electroshock induced seizures. PMID:740559

Misra, V S; Pandey, R N; Dua, P R

1978-01-01

268

Separation of positional CPP isomers by chiral HPLC-DAD of seized tablets  

Microsoft Academic Search

Meta-chlorophenylpiperazine, one of the synthetic piperazine-derived designer drugs, is to date controlled as an illicit substance\\u000a in five European member states. Depending on the position of the chlorine atom, different positional isomers of CPP (ortho-, meta- and para-) are possible. Therefore, there is a need to develop an analytical method for the separation and identification of the three\\u000a 1-chlorophenylpiperazines in

Jennifer Schürenkamp; Justus Beike; Heidi Pfeiffer; Helga Köhler

2011-01-01

269

Modification of Marine Natural Product Ningalin B and SAR Study Lead to Potent P-Glycoprotein Inhibitors  

PubMed Central

In this study, new marine ningalin B analogues containing a piperazine or a benzoloxy group at ring C have been synthesized and evaluated on their P-gp modulating activity in human breast cancer and leukemia cell lines. Their structure-activity relationship was preliminarily studied. Compounds 19 and 20 are potent P-gp inhibitors. These two synthetic analogues of permethyl ningalin B may be potentially used as effective modulators of P-gp-mediated drug resistance in cancer cells. PMID:25329704

Yang, Chao; Wong, Iris L. K.; Jin, Wen Bin; Jiang, Tao; Chow, Larry M. C.; Wan, Sheng Biao

2014-01-01

270

Pharmacokinetics of Buspirone Extended-Release Tablets: A Single-Dose Study  

Microsoft Academic Search

The objective of this study is to evaluate the absorption of buspirone and its biotransformation to 1-(2-pyrimidinyl) piperazine (1-PP) from two different extended-release (ER) formulations of buspirone HCl tablets (12-hour and 24-hour in vitro release) and from a commercially available immediate-release (IR) tablet. A single dose of the 30 mg ER tablets was compared with two doses of the 15

Adel Sakr; Mahalaxmi Andheria

2001-01-01

271

Vardenafil: structural basis for higher potency over sildenafil in inhibiting cGMP-specific phosphodiesterase-5 (PDE5)  

Microsoft Academic Search

Phosphodiesterase-5 (PDE5) inhibitors act by competing with the substrate, cGMP, for the catalytic site of the enzyme. Two commercialized PDE5 inhibitors, sildenafil and vardenafil, are being used to treat erectile dysfunction. These two compounds differ in the heterocyclic ring system used to mimic the purine ring of cGMP. They also differ in the substituent (ethyl\\/methyl) of a piperazine side chain.

Jackie D Corbin; Alfreda Beasley; Mitsi A Blount; Sharron H Francis

2004-01-01

272

Dielectric studies of water absorbed in epoxies  

E-print Network

consisting of chains of water molecules. In this thesis, dielectric spectroscopy was used to investigate the behavior of water absorbed in a model epoxy/amine polymer system (diglycidyl ether of bisphenol A cured with amino ethyl piperazine). Dielectric... OF TABLES TABLE I Analysis of Purified DER-332 Epoxy Resin. II Analysis of DEH-3g Curing Agent . III Epoxy Film Thickness Measurements . IV Relative Humidity Comparison. V WLF Comparison. VI Comparison of Calculated Activation Energies. VII Glass...

Pham, Ha Quoc

2012-06-07

273

Binding properties of SA4503, a novel and selective ? 1 receptor agonist  

Microsoft Academic Search

The binding profiles of SA4503 (1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride), a novel ? receptor ligand, to ?1 and ?2 receptor subtypes in guinea pig and rat brain membranes were evaluated. SA4503 showed a high affinity for the ?1 receptor subtype labeled by (+)-[3H]pentazocine (IC50 = 17.4 ± 1.9 nM), while it had about 100-fold less affinity for the ?2 receptor subtype labeled by

Kiyoshi Matsuno; Minako Nakazawa; Kazuyoshi Okamoto; Yoichi Kawashima; Shiro Mita

1996-01-01

274

Preclinical profile of a novel metabotropic glutamate receptor 5 positive allosteric modulator  

Microsoft Academic Search

Recent reports have indicated that patients with schizophrenia have a profound hypo-functionality of glutamatergic signaling pathways. Positive allosteric modulation of mGlu5 receptor has been postulated to augment NMDA function and thereby alleviate the glutamatergic hypo-function observed in schizophrenic patients. Here we report the in vitro and in vivo characterization of CPPZ (1-(4-(2-chloro-4-fluorophenyl)piperazin-1-yl)-2-(pyridin-4-ylmethoxy)ethanone), a structurally novel positive allosteric modulator selective for

Nathan Spear; Reto A. Gadient; Deidre E. Wilkins; MyLinh Do; Jeffrey S. Smith; Kim L. Zeller; Patricia Schroeder; Minli Zhang; Jalaj Arora; Vijay Chhajlani

2011-01-01

275

Cutaneous drug eruption from cetirizine and hydroxyzine  

Microsoft Academic Search

Topical application of the antihistamines commonly leads to sensitization for patients, but skin reactions provoked by their systemic use are very rare. The antihistamines cetirizine and hydroxyzine are piperazine derivatives, on the structural basis of an ethylenediamine, but the cross-reactions between the 2 have rarely been reported. A 44-year-old man visited because of the generalized morbilliform eruptions with pruritus over

Bark-Lin Lew; Choong-Rim Haw; Mu-Hyoung Lee

2004-01-01

276

Chlorophenylpiperazine analogues as high affinity dopamine transporter ligands.  

PubMed

Selective ?2 ligands continue to be an active target for medications to attenuate the effects of psychostimulants. In the course of our studies to determine the optimal substituents in the ?2-selective phenyl piperazines analogues with reduced activity at other neurotransmitter systems, we discovered that 1-(3-chlorophenyl)-4-phenethylpiperazine actually had preferentially increased affinity for dopamine transporters (DAT), yielding a highly selective DAT ligand. PMID:24211020

Motel, William C; Healy, Jason R; Viard, Eddy; Pouw, Buddy; Martin, Kelly E; Matsumoto, Rae R; Coop, Andrew

2013-12-15

277

Effects of cetirizine dihydrochloride on human lymphocytes in vitro: micronucleus induction. Evaluation of clastogenic and aneugenic potential using CREST and FISH assays  

Microsoft Academic Search

\\u000a Abstract Cetirizine dihydrocloride, a widely administered antiallergic drug with the amine piperazine in its molecule, was studied\\u000a as to its ability to cause micronucleus formation in human lymphocyte cultures treated in vitro. Peripheral lymphocytes from\\u000a four different donors were cultured and treated with different concentrations of the compound. Cetirizine dihydrocloride was\\u000a shown to induce enhanced micronucleus frequency in a dose-dependent

D. Vlastos; G. Stephanou

1998-01-01

278

Rhodium catalyzed hydroformylation of 1,1-bis( p-fluorophenyl)allyl or propargyl alcohol: a key step in the synthesis of Fluspirilen and Penfluridol  

Microsoft Academic Search

Fluspirilen (1) and Penfluridol (2), two neuroleptic agents, belong to a wide class of pharmaceuticals that contain in their molecules a 4,4-bis(p-fluorophenyl)butyl group bound to a nitrogen atom of a pyrrolidine, piperidine or piperazine moiety. A key intermediate for the synthesis of compounds 1 and 2, 4,4-bis(p-fluorophenyl)butylbromide (15), has been prepared starting from commercially available 4,4?-difluorobenzophenone (7) following a preparative

Carlo Botteghi; Mauro Marchetti; Stefano Paganelli; Francesco Persi-Paoli

2001-01-01

279

Intercalation of Cyclic Amines into ?-Titanium Phosphate  

Microsoft Academic Search

The intercalation of some amines (aniline, benzylamine, cyclohexylamine,piperidine, pyridine, pyrazine and piperazine) into a-titaniumphosphate, Ti(HPO4)2×H2O,has been investigated by the batch method and\\/or by exposing the host to thevapour of the amines. The changes in the interlayer distance of the solidduring the intercalation process was followed by X-ray powder diffraction.The new intercalates were characterised by chemical and thermal analysis.Materials with a

Aránzazu Espina; Enrique Jaimez; Sergei A. Khainakov; Camino Trobajo; José R. García; Julio Rodríguez

1998-01-01

280

Discovery of a Novel Series of CHK1 Kinase Inhibitors with a Distinctive Hinge Binding Mode  

PubMed Central

A novel series of CHK1 inhibitors with a distinctive hinge binding mode, exemplified by 2-aryl-N-(2-(piperazin-1-yl)phenyl)thiazole-4-carboxamide, was discovered through high-throughput screening using the affinity selection–mass spectrometry (AS-MS)-based Automated Ligand Identification System (ALIS) platform. Structure-based ligand design and optimization led to significant improvements in potency to the single digit nanomolar range and hundred-fold selectivity against CDK2. PMID:24900442

2012-01-01

281

Synthesis and antibacterial evaluation of novel 8-fluoro Norfloxacin derivatives as potential probes for methicillin and vancomycin-resistant Staphylococcus aureus  

Microsoft Academic Search

A series of novel 8-fluoro Norfloxacin derivatives and the hybrids of its piperazinyl derivatives incorporated with 1,3,5-triazine and pyrimidine were synthesized. All the above compounds were evaluated for their antibacterial activity against Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus and methicillin & vancomycin-resistant S. aureus. Among all, compounds having Morpholine, N-methyl\\/phenyl\\/benzyl\\/pyrimidinyl piperazines and n-butylamine substitution at C-7 position, have shown increased potency

Naresh Sunduru; Leena Gupta; Kuldeep Chauhan; Nripendra N. Mishra; Praveen K. Shukla; Prem M. S. Chauhan

2011-01-01

282

THEJOURNALOF BIOLOGICALCHEMISTRY 0 1985by The American Societyof Biological Chemists, Inc.  

E-print Network

of 10 ~ L MTbC13 with 100 p~ dipicolinic acid free acid forms, respectively, of piperazine-N,N"bis(2-carboxyglutamic acid; Ln3+, general for all lanthanides; F-1, bovine prothrombinfragment 1 (residues 1-156);1-1, bovine prothrombinintermediate 1 (residues 157-582); K,PIPES, Na2PIPES, PIPES,dipotassium, disodium, and acid); TbDPA, solution

Thomas, David D.

283

Evaluation of alkanolamine solutions for carbon dioxide removal in cross-flow rotating packed beds  

Microsoft Academic Search

The removal of CO2 from a 10vol% CO2 gas by chemical absorption with 30wt% alkanolamine solutions containing monoethanolamine (MEA), piperazine (PZ), and 2-amino-2-methyl-1-propanol (AMP) in the cross-flow rotating packed bed (RPB) was investigated. The CO2 removal efficiency increased with rotor speed, liquid flow rate and inlet liquid temperature. However, the CO2 removal efficiency decreased with gas flow rate. Also, the

Chia-Chang Lin; Yu-Hong Lin; Chung-Sung Tan

2010-01-01

284

Lomefloxacinium picrate.  

PubMed

IN THE CATION OF THE TITLE COMPOUND [SYSTEMATIC NAME: (RS)-4-(3-carb-oxy-1-ethyl-6,8-difluoro-4-oxo-1,4-dihydro-quinolin-7-yl)-2-methyl-piperazin-1-ium 2,4,6-trinitro-phenolate], C(17)H(20)F(2)N(3)O(3) (+)·C(6)H(2)N(3)O(7) (-), the piper-azine ring adopts a slightly distorted chair conformation and contains a protonated N atom. An intra-molecular O-H?O hydrogen bond occurs in the cation. The dihedral angles between the mean planes of the six-atom piperazine ring and the 10-atom fused ring system is 43.3?(5)°. The picrate anion inter-acts with the protonated N atom of an adjacent cation through a bifurcated N-H?(O,O) three-center hydrogen bond. Strong N-H?O hydrogen bonds in concert with weak ?-? stacking inter-actions [centroid-centroid distance = 3.6460?(14)?Å] dominate the crystal packing, creating a two-dimensional network structure along [011]. PMID:21523140

Jasinski, Jerry P; Butcher, Ray J; Siddegowda, M S; Yathirajan, H S; Hakim Al-Arique, Q N M

2011-01-01

285

Antidepressant and antipsychotic activity of new quinoline- and isoquinoline-sulfonamide analogs of aripiprazole targeting serotonin 5-HT?A/5-HT?A/5-HT? and dopamine D?/D? receptors.  

PubMed

A series of new quinoline- and isoquinoline-sulfonamide analogs of aripiprazole was synthesized to explore the influence of two structural features - replacement of ether/amide moiety with sulfonamide one, and localization of a sulfonamide group in the azine moiety. In contrast to aripiprazole, compound 33 (N-(3-(4-(2,3-dichlorophenyl)piperazin-1-yl)propyl)quinoline-7-sulfonamide) and 39 (N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)isoquinoline-3-sulfonamide) displaying multireceptor 5-HT(1A)/5-HT(2A)/5-HT(7)/D(2)/D(3) profile, and behaving as 5-HT(1A) agonists, D(2) partial agonists, and 5-HT(2A)/5-HT(7) antagonists, produced significant antidepressant activity in FST in mice. On the other hand, their 4-isoquinolinyl analog 40 (N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)isoquinoline-4-sulfonamide), with similar receptor binding and functional profile, additionally displayed remarkable antipsychotic properties in the MK-801-induced hyperlocomotor activity in mice. PMID:23279866

Zajdel, Pawe?; Marciniec, Krzysztof; Ma?lankiewicz, Andrzej; Grychowska, Katarzyna; Sata?a, Grzegorz; Duszy?ska, Beata; Lenda, Tomasz; Siwek, Agata; Nowak, Gabriel; Partyka, Anna; Wróbel, Dagmara; Jastrz?bska-Wi?sek, Magdalena; Bojarski, Andrzej J; Weso?owska, Anna; Paw?owski, Maciej

2013-02-01

286

1-Piperonylpiperazinium picrate  

PubMed Central

In the cation of the title salt [systematic name: 4-(2H-1,3-benzodioxol-5-ylmeth­yl)piperazin-1-ium 2,4,6-tri­nitro­phen­o­late], C12H17N2O2 +·C6H2N3O7 ?, the piperazine ring adopts a slightly disordered chair conformation. The piperonyl ring system and the piperazine ring are twisted with respect to each other with an N—C—C—C torsion angle of 40.7?(2)°. In the anion, the dihedral angles between the mean planes of the nitro substituents ortho to the phenolate O atom and the mean plane of the phenyl ring are 28.8?(9) and 32.2?(8)°. In contrast, the nitro group in the para position lies much closer to the aromatic ring plane, subtending a dihedral angle of 3.0?(1)°. In the crystal, the cations and anions inter­act through N—H?O hydrogen bonds and a weak C—H?O inter­action. Weak C—H?O inter­actions are also observed between the anions, forming R 2 2(10) graph-set ring motifs. In addition, a weak centroid–centroid ?–? stacking inter­action between the aromatic rings of the cation and the anion, with an inter­centroid distance of 3.7471?(9)?Å, contributes to the crystal packing, resulting in a two-dimensional network along (10-1). PMID:24764915

Kavitha, Channappa N.; Kaur, Manpreet; Anderson, Brian J.; Jasinski, Jerry P.; Yathirajan, H. S.

2014-01-01

287

Targeting tumor hypoxia with 2-nitroimidazole-indocyanine green dye conjugates  

PubMed Central

Abstract. Tumor hypoxia is a major indicator of treatment resistance to chemotherapeutic drugs, and fluorescence optical tomography has tremendous potential to provide clinically useful, functional information by identifying tumor hypoxia. The synthesis of a 2-nitroimidazole-indocyanine green conjugate using a piperazine linker (piperazine-2-nitroimidazole-ICG) capable of robust fluorescent imaging of tumor hypoxia is described. In vivo mouse tumor imaging studies were completed and demonstrate an improved imaging capability of the new dye relative to an earlier version of the dye that was synthesized with an ethanolamine linker (ethanolamine-2-nitroimidazole-ICG). Mouse tumors located at imaging depths of 1.5 and 2.0 cm in a turbid medium were imaged at various time points after intravenous injection of the dyes. On average, the reconstructed maximum fluorescence concentration of the tumors injected with piperazine-2-nitroimidazole-ICG was twofold higher than that injected with ethanolamine-2-nitroimidazole-ICG within 3 h postinjection period and 1.6 to 1.7 times higher beyond 3 h postinjection. The untargeted bis-carboxylic acid ICG completely washed out after 3 h postinjection. Thus, the optimal window to assess tumor hypoxia is beyond 3 h postinjection. These findings were supported with fluorescence images of histological sections of tumor samples and an immunohistochemistry technique for identifying tumor hypoxia. PMID:23764695

Xu, Yan; Zanganeh, Saeid; Mohammad, Innus; Aguirre, Andres; Wang, Tianheng; Yang, Yi; Kuhn, Liisa; Smith, Michael B.; Zhu, Quing

2013-01-01

288

Structural aspects of intermolecular interactions in the solid state of 1,4-dibenzylpiperazines bearing nitrile or amidine groups.  

PubMed

The crystal structures of the title 1,4-bis(4-cyanobenzyl)piperazine (1) and 1,4-bis(4-amidinobenzyl)piperazine tetrahydrochloride tetrahydrate (2) are reported. Compound (1) crystallizes in the triclinic space group P\\bar 1 and compound (2) in the monoclinic space group P21/n. In both (1) and (2) the asymmetric unit contains one half of the molecule because the central piperazine rings were located across a symmetry center. The packing of both molecules was dominated by hydrogen bonds. The crystal lattice of (1) was formed by weak C-H...N and C-H...? interactions. The crystal structure of (2) was completely different, with cations as well as chloride anions and water molecules taking part in intermolecular interactions. Single-crystal X-ray diffraction studies combined with density functional theory (DFT) calculations allowed the characterization of the intermolecular interactions in those two systems having different types of very strong electrophilic groups: non-ionic nitrile and ionic amidine. Chemical shift data from (13)C CP/MAS (Cross Polarization Magic Angle Spinning) NMR spectra were analyzed using the different procedures for the theoretical computation of shielding constants. PMID:25274515

Rezler, Mateusz; Zo?ek, Teresa; Wolska, Irena; Maciejewska, Dorota

2014-10-01

289

Structural aspects of intermolecular interactions in the solid state of 1,4-dibenzylpiperazines bearing nitrile or amidine groups  

PubMed Central

The crystal structures of the title 1,4-bis(4-cyanobenzyl)piperazine (1) and 1,4-bis(4-amidinobenzyl)piperazine tetrahydrochloride tetrahydrate (2) are reported. Compound (1) crystallizes in the triclinic space group and compound (2) in the monoclinic space group P21 /n. In both (1) and (2) the asymmetric unit contains one half of the molecule because the central piperazine rings were located across a symmetry center. The packing of both molecules was dominated by hydrogen bonds. The crystal lattice of (1) was formed by weak C—H?N and C—H?? interactions. The crystal structure of (2) was completely different, with cations as well as chloride anions and water molecules taking part in intermolecular interactions. Single-crystal X-ray diffraction studies combined with density functional theory (DFT) calculations allowed the characterization of the intermolecular interactions in those two systems having different types of very strong electrophilic groups: non-ionic nitrile and ionic amidine. Chemical shift data from 13C CP/MAS (Cross Polarization Magic Angle Spinning) NMR spectra were analyzed using the different procedures for the theoretical computation of shielding constants. PMID:25274515

Rezler, Mateusz; Zolek, Teresa; Wolska, Irena; Maciejewska, Dorota

2014-01-01

290

Anti-Trichomonas vaginalis activity from triterpenoid derivatives.  

PubMed

Trichomonas vaginalis is a flagellated parasite that causes trichomonosis, the most common non-viral sexually transmitted disease (STD) in the world. Worryingly, trichomonosis is associated to increased transmission of HIV. Due to high frequency of the infection during pregnancy and the development of metronidazole-resistant isolates, therapeutic alternatives to 5-nitroimidazole are being searched. Triterpenes are natural products presenting several biological activities such as anti-protozoal activity. The aim of this study was to evaluate the in vitro anti-T. vaginalis activity from betulinic and ursolic acids, as well as semisynthetic derivatives obtained. Compounds obtained from betulinic acid presented better activity than those from ursolic acid. Piperazine derivatived from betulinic acid presented minimum inhibitory concentration (MIC) value of 91.2 ?M, and the kinetic growth curve performed with parasites treated with this most active compound revealed complete inhibition of trophozoite proliferation at 2 h of incubation and total abolition of trophozoite growth in 24 h, revealing that the piperazine derivative is an efficient trichomonacidal molecule. The same compound promoted total erythrocyte lysis and lactate dehydrogenase (LDH) liberation of 83 and 100% (at 45.6 and 91.2 ?M, respectively), indicating parasite membrane damage. The piperazine derivative demonstrated cytotoxic effect against the HMVII and HeLa cell lineages at the MIC value. This is the first report of semisynthetic triterpenoid derivatives with anti-T. vaginalis activity, revealing the high potential of these compounds as trichomonacidal agents. PMID:24880238

Innocente, Adrine Maria; Vieira, Patrícia de Brum; Frasson, Amanda Piccoli; Casanova, Bruna Bento; Gosmann, Grace; Gnoatto, Simone Cristina Baggio; Tasca, Tiana

2014-08-01

291

Paper spray and extraction spray mass spectrometry for the direct and simultaneous quantification of eight drugs of abuse in whole blood.  

PubMed

Determination of eight drugs of abuse in blood has been performed using paper spray or extraction spray mass spectrometry in under 2 min with minimal sample preparation. A method has been optimized for quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), morphine, cocaine, and ?9-tetrahydrocannabinol (THC) from a single blood spot. Sample to sample variations of 1-5% relative standard deviation were achieved using stable isotope-labeled internal standards and tandem mass spectrometry. Limits of detection for all drugs were below typical physiological and toxicological levels. Paper spray and extraction spray each used less than 10 ?L of whole blood. These methods exhibit the potential for performing rapid and high-throughput assays for selective on-site multicompound quantitative screening of illicit drugs. PMID:24970379

Espy, Ryan D; Teunissen, Sebastiaan Frans; Manicke, Nicholas E; Ren, Yue; Ouyang, Zheng; van Asten, Arian; Cooks, R Graham

2014-08-01

292

Heat of Dissolution Measurements for CO2 in Mixed Alkanolamine Solvents  

SciTech Connect

The main objective of this research was to measure heat of dissolution of CO{sub 2} in carefully mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture process, and for better understanding of the thermodynamics of CO{sub 2}-Alkanolamine systems. An experimental set-up has been designed using the Isothermal Micro Calorimeter for measuring the solubilities and enthalpies of CO{sub 2} in mixed solvents made of MEA, MDEA, PZ, KF and water. All the measurements were done at temperatures 15, 40, and 75 C by maintaining a constant pressure of 100 psig. A detailed study has been done on the variation of solubilities and enthalpies over a wide range of temperatures, pressures and concentrations, by extracting the information from the literature.

Vinayak Kabadi

2007-03-17

293

Discrimination and identification of regioisomeric ?-keto analogues of 3,4-methylenedioxyamphetamines by gas chromatography-mass spectrometry  

Microsoft Academic Search

Very recently, ?-keto derivatives of 3,4-methylenedioxyamphetamines (MDAs) have appeared on the illicit drug market. In the\\u000a present study, we synthesized three isomers of ?-keto derivatives of MDAs, 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one\\u000a (bk-MBDB), 2-ethylamino-1-(3,4-methylenedioxyphenyl) propan-1-one (bk-MDEA), and 2-dimethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one\\u000a (bk-MDDMA), and measured their electron ionization mass spectra without and with trifluoroacetyl (TFA) derivatization using\\u000a gas chromatography-mass spectrometry (GC-MS). Although the spectral profiles of the three

Kei Zaitsu; Munehiro Katagi; Hiroe T. Kamata; Akihiro Miki; Hitoshi Tsuchihashi

2008-01-01

294

pH dependent efflux of methamphetamine derivatives and their reversal through human Caco-2 cell monolayers.  

PubMed

The purpose of this study was to investigate possible efflux mechanisms involved in amphetamine derivative transport such as for 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), para-methoxyamphetamine (p-MA), dexamphetamine and pseudoephedrine, especially across pH gradients that exist in intestinal or kidney transport. This was determined using our Caco-2 subclone, CLEFF9. Transport of the amphetamine derivatives was evaluated at pH 7.4 and pH 6/7.4+/-efflux inhibitors. Na+-H+ transporter inhibition via carbonyl cyanide-4-trifluoromethoxy phenylhydrazone (FCCP), and metabolic inhibition using Na-azide and Na-orthovanadate were also conducted, as well as using noradrenalin, adrenalin and other inhibitors of a range of carrier mediated transport systems such as histamine, organic cation transporters and dopamine carrier systems. At pH 7.4, the rate of transport for dexamphetamine, pseudoephedrine and MDMA in both apical to basolateral and reverse directions was all very rapid, confirming extensive passive diffusion at systemic pH. However, creating a pH 6.0/7.4 gradient showed marked increase in basolateral to apical transport of all amphetamines tested, with dexamphetamine, MDEA, MDMA and p-MA having a net efflux ratio of around 16, 14, 13 and 11 respectively and this was not reversed with P-glycoprotein inhibitors. Azide, FCCP, adrenalin, noradrenalin and reserpine were able to reduce the efflux by 2 to 3 fold, although tetraethylammonium could not. This suggested that extraneuronal monoamine transporters (hEMT) could be involved. This data suggests that elevated endogenous adrenalin levels may reduce amphetamine removal from the body based on these in vitro studies. Also, the use of stomach acid lowering drugs could result in more rapid systemic uptake of these amphetamine derivatives. PMID:18638470

Crowe, Andrew; Diep, Susanna

2008-09-11

295

Gas separation using ion exchange membranes for producing hydrogen from synthesis gas  

SciTech Connect

The main goal of this project is to demonstrate the use of facilitated transport membranes to separate gases resulting from the formation of H{sub 2}, specifically C0{sub 2} and H{sub 2}S from CO and H{sub 2}. As part of this goal a field test is performed at a producing natural gas plant (Carter Creek Chevron Natural Gas Plant, Evanston, WY) to evaluate the performance and long term stability of candidate membranes. Laboratory work at the National Institute of Standard and Technology (NIST) leads and parallels the field tests. Through a series of tests in the WIST laboratory and at the Chevron/Carter Creek test rig, the investigators are establishing the apparent separation and productivity capabilities of polymer membranes imbibed with various solvents and chemical carriers. In some samples the membranes are also subjected to solvent-swelling heat treatment (gel-treatment). The polymer material is polyperfluorosufonic acid (PFSA-Nafion). The chemical carriers, e.g. methyldiethanolamine (EDA) and ethylenediamine (EDA) enhance the transport and selectivity of the membrane. They may be in solution with H{sub 2}0, glycerol, ethylene glycol, and n-methylpyrrolidone (NMP). Nafion 117 (NE117) is a commercial film, 200 microns thick, which is available from DuPont Co. A developmental polymer film, Nafion 111 (NE111) 30--40 microns thick was made available by the DuPont Co.

Pellegrino, J.J.; Giarratano, P.J.

1992-01-01

296

Gas separation using ion exchange membranes for producing hydrogen from synthesis gas. Quarterly report 22 covering the period October 1, 1991--December 31, 1991  

SciTech Connect

The main goal of this project is to demonstrate the use of facilitated transport membranes to separate gases resulting from the formation of H{sub 2}, specifically C0{sub 2} and H{sub 2}S from CO and H{sub 2}. As part of this goal a field test is performed at a producing natural gas plant (Carter Creek Chevron Natural Gas Plant, Evanston, WY) to evaluate the performance and long term stability of candidate membranes. Laboratory work at the National Institute of Standard and Technology (NIST) leads and parallels the field tests. Through a series of tests in the WIST laboratory and at the Chevron/Carter Creek test rig, the investigators are establishing the apparent separation and productivity capabilities of polymer membranes imbibed with various solvents and chemical carriers. In some samples the membranes are also subjected to solvent-swelling heat treatment (gel-treatment). The polymer material is polyperfluorosufonic acid (PFSA-Nafion). The chemical carriers, e.g. methyldiethanolamine (EDA) and ethylenediamine (EDA) enhance the transport and selectivity of the membrane. They may be in solution with H{sub 2}0, glycerol, ethylene glycol, and n-methylpyrrolidone (NMP). Nafion 117 (NE117) is a commercial film, 200 microns thick, which is available from DuPont Co. A developmental polymer film, Nafion 111 (NE111) 30--40 microns thick was made available by the DuPont Co.

Pellegrino, J.J.; Giarratano, P.J.

1992-01-01

297

Interactions of anthelmintic drugs in Caenorhabditis elegans neuro-muscular ion channel mutants.  

PubMed

Due to the increasing development of anthelmintic resistance in nematodes worldwide, it is important to search for anthelmintic compounds with new modes of action and also to investigate the possibility to combine compounds with possible synergistic effects. There might also be the chance to take advantage of the fact that nematode populations which have developed resistance against one anthelmintic class might respond hypersusceptibly to another drug class. The aim of this study was to investigate responses of Caenorhabditis elegans populations with mutations in neuro-muscular ion channels to different anthelmintic classes. Furthermore, potential synergistic effects between two anthelmintic compounds from different classes, i.e. emodepside and tribendimidine, were studied. Although there was neither a synergistic nor an antagonistic effect between emodepside and tribendimidine, other types of interactions could be identified. The C. elegans GABAA-receptor (GABAA-R) unc-49 mutants, showing decreased emodepside susceptibility, were more susceptible to tribendimidine than wild-type C. elegans. In contrast, the reverse phenomenon - hypersusceptibility to emodepside in tribendimidine resistant acetylcholine-receptor (AChR) loss of function mutants - was not observed. Moreover, the slo-1 mutant strain (completely emodepside resistant) also showed hypersusceptibility to piperazine. Interestingly, neither the GABAA-R unc-49 mutants nor the AChR mutants showed decreased susceptibility against piperazine, although there were some studies that indicated an involvement of GABAA-R or AChR in the piperazine mode of action. In conclusion, the present study provides evidence suggesting that interactions between commercially available anthelmintic drugs with different modes of action might be a relatively common phenomenon but this has to be carefully worked out for each anthelmintic and each anthelmintic drug combination. Moreover, results obtained in C. elegans will have to be confirmed using parasitic nematodes in the future. PMID:23707730

Miltsch, Sandra M; Krücken, Jürgen; Demeler, Janina; Ramünke, Sabrina; Harder, Achim; von Samson-Himmelstjerna, Georg

2013-12-01

298

Diketopiperazine Derivatives from the Marine-Derived Actinomycete Streptomyces sp. FXJ7.328  

PubMed Central

Five new diketopiperazine derivatives, (3Z,6E)-1-N-methyl-3-benzylidene-6-(2S-methyl-3-hydroxypropylidene)piperazine-2,5-dione (1), (3Z,6E)-1-N-methyl-3-benzylidene-6-(2R-methyl-3-hydroxypropylidene)piperazine-2,5-dione (2), (3Z,6Z)-3-(4-hydroxybenzylidene)-6-isobutylidenepiperazine-2,5-dione (3), (3Z,6Z)-3-((1H-imidazol-5-yl)-methylene)-6-isobutylidenepiperazine-2,5-dione (4), and (3Z,6S)-3-benzylidene-6-(2S-but-2-yl)piperazine-2,5-dione (5), were isolated from the marine-derived actinomycete Streptomyces sp. FXJ7.328. The structures of 1–5 were determined by spectroscopic analysis, CD exciton chirality, the modified Mosher’s, Marfey’s and the C3 Marfey’s methods. Compound 3 showed modest antivirus activity against influenza A (H1N1) virus with an IC50 value of 41.5 ± 4.5 ?M. In addition, compound 6 and 7 displayed potent anti-H1N1 activity with IC50 value of 28.9 ± 2.2 and 6.8 ± 1.5 ?M, respectively. Due to the lack of corresponding data in the literature, the 13C NMR data of (3Z,6S)-3-benzylidene-6-isobutylpiperazine-2,5-dione (6) were also reported here for the first time. PMID:23538868

Wang, Pei; Xi, Lijun; Liu, Peipei; Wang, Yi; Wang, Wei; Huang, Ying; Zhu, Weiming

2013-01-01

299

Behavioral approach to nondyskinetic dopamine antagonists: identification of seroquel.  

PubMed

A great need exists for antipsychotic drugs which will not induce extrapyramidal symptoms (EPS) and tardive dyskinesias (TDs). These side effects are deemed to be a consequence of nonselective blockade of nigrostriatal and mesolimbic dopamine D2 receptors. Nondyskinetic clozapine (1) is a low-potency D2 dopamine receptor antagonist which appears to act selectively in the mesolimbic area. In this work dopamine antagonism was assessed in two mouse behavioral assays: antagonism of apomorphine-induced climbing and antagonism of apomorphine-induced disruption of swimming. The potential for the liability of dyskinesias was determined in haloperidol-sensitized Cebus monkeys. Initial examination of a few close cogeners of 1 enhanced confidence in the Cebus model as a predictor of dyskinetic potential. Considering dibenzazepines, 2 was not dyskinetic whereas 2a was dyskinetic. Among dibenzodiazepines, 1 did not induce dyskinesias whereas its N-2-(2-hydroxyethoxy)ethyl analogue 3 was dyskinetic. The emergence of such distinctions presented an opportunity. Thus, aromatic and N-substituted analogues of 6-(piperazin-1-yl)-11H-dibenz[b,e]azepines and 11-(piperazin-1-yl)dibenzo[b,f][1,4]thiazepines and -oxazepines were prepared and evaluated. 11-(4-[2-(2-Hydroxyethoxy)ethyl]piperazin-1-yl)dibenzo[b,f][1,4]thiazepine (23) was found to be an apomorphine antagonist comparable to clozapine. It was essentially nondyskinetic in the Cebus model. With 23 as a platform, a number of N-substituted analogues were found to be good apomorphine antagonists but all were dyskinetic. PMID:11462978

Warawa, E J; Migler, B M; Ohnmacht, C J; Needles, A L; Gatos, G C; McLaren, F M; Nelson, C L; Kirkland, K M

2001-02-01

300

Rapid room temperature synthesis of electrocatalytically active Au nanostructures.  

PubMed

We describe a facile route for the one-pot room temperature synthesis of anisotropic Au nanostructures in aqueous solution in the absence of seeds or surfactants and their electrocatalytic activity. The Au nanostructures were synthesized using piperazine derivatives 1-(2-hydroxyethyl)piperazine and 1,4-Bis(2-hydroxyethyl)piperazine as reducing agents. The Au nanostructures were characterized by spectral, transmission electron microscopic (TEM), X-ray diffraction and electrochemical measurements. The absorption spectrum of colloidal nanoparticles displays two bands ~580 and ~930 nm, corresponding to the dipole and quadrupole plasmon resonance, respectively. TEM measurements show that the Au nanostructures have penta-twined polyhedral shape with an average size of 52 nm. X-ray and selected area electron diffraction patterns reveal the existence of face centered cubic nanocrystalline Au. The concentration of Au(III) controls the stability of the nanoparticles. The nanoparticles were immobilized on 3-D silicate network pre-assembled on a conducting support to examine their electrocatalytic activity. The nanoparticle-based electrochemical interface was characterized by spectral, voltammetric and impedance measurements. The nanoparticle shows high catalytic activity in the oxidation of NADH and reduction of oxygen. Unique inverted 'V' shape voltammogram was obtained for the oxidation of NADH at less positive potential. The nanoparticle-based interface favors two-step four-electron reduction of oxygen to water in neutral pH. Significant decrease in the overpotential for the oxidation of NADH and reduction of oxygen with respect to the polycrystalline Au electrode was observed. The electrocatalytic performance of the polyhedral nanoparticle is compared with the conventional citrate stabilized spherical nanoparticles. PMID:20970809

Das, Ashok Kumar; Raj, C Retna

2011-01-15

301

Three-dimensional hydrogen-bonded framework structures in flunarizinium nicotinate and flunarizinediium bis(4-toluenesulfonate) dihydrate.  

PubMed

The structures of two salts of flunarizine, namely 1-bis[(4-fluorophenyl)methyl]-4-[(2E)-3-phenylprop-2-en-1-yl]piperazine, C26H26F2N2, are reported. In flunarizinium nicotinate {systematic name: 4-bis[(4-fluorophenyl)methyl]-1-[(2E)-3-phenylprop-2-en-1-yl]piperazin-1-ium pyridine-3-carboxylate}, C26H27F2N2(+)·C6H4NO2(-), (I), the two ionic components are linked by a short charge-assisted N-H...O hydrogen bond. The ion pairs are linked into a three-dimensional framework structure by three independent C-H...O hydrogen bonds, augmented by C-H...?(arene) hydrogen bonds and an aromatic ?-? stacking interaction. In flunarizinediium bis(4-toluenesulfonate) dihydrate {systematic name: 1-[bis(4-fluorophenyl)methyl]-4-[(2E)-3-phenylprop-2-en-1-yl]piperazine-1,4-diium bis(4-methylbenzenesulfonate) dihydrate}, C26H28F2N2(2+)·2C7H7O3S(-)·2H2O, (II), one of the anions is disordered over two sites with occupancies of 0.832?(6) and 0.168?(6). The five independent components are linked into ribbons by two independent N-H...O hydrogen bonds and four independent O-H...O hydrogen bonds, and these ribbons are linked to form a three-dimensional framework by two independent C-H...O hydrogen bonds, but C-H...?(arene) hydrogen bonds and aromatic ?-? stacking interactions are absent from the structure of (II). Comparisons are made with some related structures. PMID:25093364

Kavitha, Channappa N; Yathirajan, Hemmige S; Kaur, Manpreet; Hosten, Eric C; Betz, Richard; Glidewell, Christopher

2014-08-15

302

Caenorhabditis elegans Neuromuscular Junction: GABA Receptors and Ivermectin Action  

PubMed Central

The prevalence of human and animal helminth infections remains staggeringly high, thus urging the need for concerted efforts towards this area of research. GABA receptors, encoded by the unc-49 gene, mediate body muscle inhibition in Caenorhabditis elegans and parasitic nematodes and are targets of anthelmintic drugs. Thus, the characterization of nematode GABA receptors provides a foundation for rational anti-parasitic drug design. We therefore explored UNC-49 channels from C. elegans muscle cultured cells of the first larval stage at the electrophysiological and behavioral levels. Whole-cell recordings reveal that GABA, muscimol and the anthelmintic piperazine elicit macroscopic currents from UNC-49 receptors that decay in their sustained presence, indicating full desensitization. Single-channel recordings show that all drugs elicit openings of ?2.5 pA (+100 mV), which appear either as brief isolated events or in short bursts. The comparison of the lowest concentration required for detectable channel opening, the frequency of openings and the amplitude of macroscopic currents suggest that piperazine is the least efficacious of the three drugs. Macroscopic and single-channel GABA-activated currents are profoundly and apparently irreversibly inhibited by ivermectin. To gain further insight into ivermectin action at C. elegans muscle, we analyzed its effect on single-channel activity of the levamisol-sensitive nicotinic receptor (L-AChR), the excitatory receptor involved in neuromuscular transmission. Ivermectin produces a profound inhibition of the frequency of channel opening without significant changes in channel properties. By revealing that ivermectin inhibits C. elegans muscle GABA and L-AChR receptors, our study adds two receptors to the already known ivermectin targets, thus contributing to the elucidation of its pleiotropic effects. Behavioral assays in worms show that ivermectin potentiates piperazine-induced paralysis, thus suggesting that their combination is a good strategy to overcome the increasing resistance of parasites, an issue of global concern for human and animal health. PMID:24743647

Hernando, Guillermina; Bouzat, Cecilia

2014-01-01

303

catena-Poly[[diaqua-zinc(II)]-?-piper-azine-1,4-diacetato-?N,O:N,O].  

PubMed

The asymmetric unit of the title compound, [Zn(C(8)H(12)N(2)O(4))(H(2)O)(2)](n), contains a Zn(II) ion residing on an inversion center, half of a centrosymmetric piperazine-1,4-diacetate ligand (L) and a water mol-ecule. The Zn(II) ion is trans-coordinated by two N,O-bidentate L ligands and by two water mol-ecules in a distorted octa-hedral geometry. In the crystal structure, inter-molecular O-H?O hydrogen bonds link polymeric chains into a three-dimensional supra-molecular structure. PMID:21578597

Bi, Jian-Hong

2009-01-01

304

Conformationally constrained analogs of N-substituted piperazinylquinolones: synthesis and antibacterial activity of N-(2,3-dihydro-4-hydroxyimino-4H-1-benzopyran-3-yl)-piperazinylquinolones.  

PubMed

A series of novel quinolone agents bearing a particular bulky and conformationally constrained bicyclic substituent (2,3-dihydro-4-hydroxyimino-4H-1-benzopyran-3-yl- moiety) on the piperazine ring of 7-piperazinyl quinolones (norfloxacin, enoxacin, ciprofloxacin, and levofloxacin) were synthesized and evaluated against a panel of Gram-positive and Gram-negative bacteria. Among these derivatives, ciprofloxacin counterpart 9c, highly inhibited the tested Gram-positive bacteria, superior to that of the reference drugs, and displayed antibacterial activity at non-cytotoxic concentrations. PMID:19544301

Emami, Saeed; Foroumadi, Alireza; Samadi, Nasrin; Faramarzi, Mohammad A; Rajabalian, Saeed

2009-07-01

305

Characterization of the Transport, Metabolism, and Pharmacokinetics of the Dopamine D3 Receptor-Selective Fluorenyl- and 2-Pyridylphenyl Amides Developed for Treatment of Psychostimulant Abuse  

PubMed Central

The recent discovery of novel high-affinity and selective dopamine D3 receptor (DA D3R) antagonists and partial agonists has provided tools with which to further elucidate the role DA D3R plays in substance abuse. The present study was conducted to evaluate the transport, metabolism, pharmacokinetics, and brain uptake of the DA D3R-selective fluorenyl amides, NGB 2904 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-9H-fluorene-2-carboxamide] fumarate) and JJC 4-077 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)-3-hydroxybutyl)-9H-fluorene-2-carboxamide hydrochloride], and the 2-pyridylphenyl amides, CJB 090 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-(pyridine-2-yl)benzamide hydrochloride] and PG 01037 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)-trans-but-2-enyl)-4-(pyridine-2-yl)benzamide hydrochloride], all of which have been studied in animal models of psychostimulant abuse. Additional screening with a panel of human and rat Supersomes was performed for NGB 2904 and PG 01037. Drug-stimulated ATPase activation assays and bidirectional transport and efflux assays were used to test for substrate specificity of NGB 2904 and PG 01037 for human and rat efflux transporters. All compounds exhibited moderate elimination half-lives, ranging from 1.49 to 3.27 h, and large volumes of distribution (5.95–14.19 l/kg). The brain-to-plasma ratios ranged from 2.93 to 11.81 and were higher than those previously reported for cocaine. Brain exposure levels of NGB 2904 and PG 01037 were significantly reduced after intraperitoneal administration compared with intravenous administration. The metabolism of these compounds was mediated primarily by CYP3A subfamilies. PG 01037 was a P-glycoprotein-transported substrate. Higher doses of these compounds are often required for in vivo action, suggesting decreased bioavailability via extravascular administration that may be attributed to high drug efflux and hepatic metabolism. These studies provide important preclinical information for optimization of next-generation D3R selective agents for the treatment of drug addiction. PMID:20228156

Mason, Clifford W.; Hassan, Hazem E.; Kim, Kang-Pil; Cao, Jianjing; Eddington, Natalie D.; Newman, Amy Hauck

2010-01-01

306

Separation and determination of chlorophenylpiperazine isomers in confiscated pills by capillary electrophoresis.  

PubMed

A simple capillary electrophoretic method with spectrophotometric UV detection at 236 nm has been developed for the selective separation and determination of 1-(2-chlorophenyl)piperazine (oCPP), 1-(3-chlorophenyl)piperazine (mCPP) and 1-(4-chlorophenyl)piperazine (pCPP) in confiscated pills. Several cyclodextrin derivatives were tested to compose the background electrolyte (BGE). The optimized BGE contained 20 mmol/L phosphoric acid adjusted to pH 2.5 with triethylamine and 10 mmol/L ?-cyclodextrin, which provided acceptable resolution of analytes and candidate interferents in less than 15 min. The analyses were performed at constant voltage of 25 kV in 60 cm (effective length 50 cm; 50 ?m i.d.) uncoated fused-silica capillary maintained at 25°C with sample injection at 4,826 Pa for 8s. Procaine at a concentration of 0.1mg/mL was used as internal standard (IS). Possible interference from other drugs such as amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, 1-(3-trifluoromethylphenyl)piperazine and cocaine was also examined. The analytical curves were linear (R(2)=0.9994-0.9995) in the range of 10-200 ?g/mL (for oCPP and mCPP) and 20-200 ?g/mL for pCPP. Limits of detection (LODs) were 2.0 ?g/mL (oCPP), 2.5?g/mL (mCPP) and 3.5 ?g/mL (pCPP). Intraday precision at three concentration levels and six replicates of each level (10, 100, 200 ?g/mL of each analyte; n=18) was evaluated for the corrected peak area ratio of analyte to IS and the migration times giving RSDs ? 4.9%. The accuracy was estimated for mCPP by a recovery test at the same three concentration levels and recoveries varied from 101.0 to 101.6%. The method has been successively applied to the analysis of 17 confiscated pills based mostly on mCPP. PMID:23831489

Siroká, Jitka; Polesel, Daniel N; Costa, Jose L; Lanaro, Rafael; Tavares, Marina F M; Polášek, Miroslav

2013-10-01

307

A novel amalgamation of 1,2,3-triazoles, piperidines and thieno pyridine rings and evaluation of their antifungal activity.  

PubMed

It is the first report of the novel amalgamation of 1,2,3-triazoles, piperidines, thieno pyridine rings and evaluation of their antifungal activity. The synthesized compounds showed interesting moderate to good antifungal activity, wherein they were able to discriminate between the two species Aspergillus flavus and Aspergillus niger of the same genus. In addition, the main highlight of this series is the sensitivity of the fungal strain Cryptococcus neoformans to the compounds having p-chlorobenzoyl (9h), methane sulfonyl (9i) and p-methylbenzene sulfonyl (9j) attached to the piperazine nitrogen. PMID:23807083

Darandale, Sunil N; Mulla, Nayeem A; Pansare, Dattatraya N; Sangshetti, Jaiprakash N; Shinde, Devanand B

2013-07-01

308

Comparative Behavioral Pharmacology of Cocaine and the Selective Dopamine Uptake Inhibitor RTI-113 in the Squirrel Monkey1  

Microsoft Academic Search

The behavioral effects of 3b-(4-chlorophenyl)tropane-2b-car- boxylic acid phenyl ester hydrochloride (RTI-113; 0.03-1.0 mg\\/ kg), a selective dopamine uptake inhibitor, were compared with those of cocaine (0.03-3.0 mg\\/kg) and 1-{2-(bis(4-fluorophenyl- )methoxy)ethyl}-4-(3-phenylpropyl)piperazine dihydrochloride (GBR 12909; 0.03-3.0 mg\\/kg) in squirrel monkeys. Intermediate doses of each drug produced significant increases in response rate maintained by a fixed-interval (FI) 300-s schedule of stimulus termination, but

LEONARD L. HOWELL; PAUL W. CZOTY; MICHAEL J. KUHAR; F. IVY CARROL

309

A fluorine 1,2-migration via aryl cation/radical/radical anion/radical sequence.  

PubMed

Irradiation of a 7-piperazino-8-fluoroquinolone causes formal 1,2-fluorine migration, piperazine loss and reduction, or nucleophile addition in 8. Product study, laser flash photolysis, and computational modeling support F(-) detachment to yield a triplet 8-quinolyl cation that either inserts intramolecularly or is trapped by Cl(-), Br(-). However, iodide and pyrrole reduce it to the radical that continues the 'redox tour' (aryl cation? radical? radical anion? radical and then again radical or radical anion) leading to the rearranged products. PMID:23869692

Pretali, Luca; Dondi, Daniele; D'Angelantonio, Mila; Manet, Ilse; Fasani, Elisa; Monti, Sandra; Bovio, Bruna; Albini, Angelo

2013-08-01

310

Cross-Modulation of Synaptic Plasticity by b-Adrenergic and 5HT1A Receptors in the Rat Basolateral Amygdala  

Microsoft Academic Search

blocked Iso- and forskolin-induced potentiation. The effect of 5-HT was mimicked by the selective 5-HT1A agonist 8-hydroxy- dipropylaminotetralin and was blocked by the selective 5-HT1A antagonist 1-(2-methoxyphenyl)-4(4-(2-phthalimido)butyl)piperazine, indicating its mediation by 5-HT1A receptors. To determine the locus of interaction, Sp-cAMPS, a membrane-permeable acti- vator of PKA, was applied, and the potentiation produced by Sp-cAMPS was completely blocked in slices pretreated

Su-Jane Wang; Li-Liang Cheng; Po-Wu Gean

1999-01-01

311

Inhibition of Acute, Latent, and Chronic-Phase Human Immunodeficiency Virus Type 1 (HIV1) Replication by a Bistriazoloacridone Analog That Selectively Inhibits HIV1 Transcription  

Microsoft Academic Search

Nanomolar concentrations of temacrazine (1,4-bis(3-(6-oxo-6H-v-triazolo(4,5,1-de)acridin-5-yl)amino-pro- pyl)piperazine) were discovered to inhibit acute human immunodeficiency virus type 1 (HIV-1) infections and suppress the production of virus from chronically and latently infected cells containing integrated proviral DNA. This bistriazoloacridone derivative exerted its mechanism of antiviral action through selective inhibition of HIV-1 transcription during the postintegrative phase of virus replication. Mechanistic studies revealed that

JIM A. TURPIN; ROBERT W. BUCKHEIT; DAVID DERSE; MELINDA HOLLINGSHEAD; KAREN WILLIAMSON; CARLA PALAMONE; M. CLAYTON OSTERLING; SHAWN A. HILL; LISA GRAHAM; CATHERINE A. SCHAEFFER; MING BU; MINGJUN HUANG; WIESLAW M. CHOLODY; CHRISTOPHER J. MICHEJDA; WILLIAM G. RICE; SAIC Frederick

1998-01-01

312

Stereoselective Synthesis of Saturated Heterocycles via Pd-Catalyzed Alkene Carboetherification and Carboamination Reactions  

PubMed Central

The development of Pd-catalyzed carboetherification and carboamination reactions between aryl/alkenyl halides and alkenes bearing pendant heteroatoms is described. These transformations effect the stereoselective construction of useful heterocycles such as tetrahydrofurans, pyrrolidines, imidazolidin-2-ones, isoxazolidines, and piperazines. The scope, limitations, and applications of these reactions are presented, and current stereochemical models are described. The mechanism of product formation, which involves an unusual intramolecular syn-insertion of an alkene into a Pd-Heteroatom bond is also discussed in detail. PMID:19183704

Wolfe, John P.

2009-01-01

313

Synthesis and optimization of 2-pyridin-3-yl-benzo[d][1,3]oxazin-4-one based inhibitors of human neutrophil elastase.  

PubMed

The hit-to-lead optimization of the HNE inhibitor 5-methyl-2-(2-phenoxy-pyridin-3-yl)-benzo[d][1,3]oxazin-4-one is described. A structure-activity relationship study that focused on the 5 and 7 benzoxazinone positions yielded the optimized 5-ethyl-7-methoxy-benzo[d][1,3]oxazin-4-one core structure. 2-[2-(4-Methyl-piperazin-1-yl)-pyridin-3-yl] derivatives of this core were shown to yield HNE inhibitors of similar potency with significantly different stabilities in rat plasma. PMID:19577470

Shreder, Kevin R; Cajica, Julia; Du, Lingling; Fraser, Allister; Hu, Yi; Kohno, Yasushi; Lin, Emme C K; Liu, Steve J; Okerberg, Eric; Pham, Lan; Wu, Jiangyue; Kozarich, John W

2009-08-15

314

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. A rigorous thermodynamic model has been developed with a stand-alone FORTRAN code to represent the CO{sub 2} vapor pressure and speciation of the new solvent. Parameters have been developed for use of the electrolyte NRTL model in AspenPlus. Analytical methods have been developed using gas chromatography and ion chromatography. The heat exchangers for the pilot plant have been ordered.

Gary T. Rochelle; Eric Chen; J. Tim Cullinane; Marcus Hilliard; Terraun Jones

2003-04-01

315

Characterization of two cyclic metabolites of sitagliptin.  

PubMed

Two novel metabolites of the dipeptidyl peptidase inhibitor sitagliptin (MK-0431, (2R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)-butan-2-amine), were identified after purification from dog urine. The metabolites (referred to as M2 and M5) were characterized by hydrogen/deuterium exchange tandem mass spectrometry and NMR spectroscopy nuclear Overhauser effect experiments as the cis and trans stereoisomers formed by cyclization of the primary amino group with the alpha carbon of the piperazine ring, following oxidative desaturation. PMID:17220240

Liu, David Q; Arison, Byron H; Stearns, Ralph A; Kim, Dooseop; Vincent, Stella H

2007-04-01

316

Diffusion of water in nanoporous NF polyamide membrane  

NASA Astrophysics Data System (ADS)

Diffusion of water sorbed in a nanofiltration (NF) polyamide membrane as studied by quasielastic neutron scattering (QENS) is reported here. The trimesoyl chloride-piperazine based NF membrane was synthesized by interfacial polymerization technique and was characterized by positron annihilation lifetime spectroscopy (PALS) and SEM techniques. PALS data shows that the membrane has an average pore size ˜4.6 Å. QENS data from water sorbed NF membrane show that the diffusion in the sorbed water occurs through jump diffusion with the jump lengths distributed randomly. Translational diffusion coefficient obtained for water sorbed in the NF membrane is found to be smaller than that of bulk water.

Sharma, V. K.; Singh, P. S.; Gautam, S.; Mitra, S.; Mukhopadhyay, R.

2009-08-01

317

Synthesis and structure-activity relationship of dihydrobenzofuran derivatives as novel human GPR119 agonists.  

PubMed

Through appropriate medicinal chemistry design tactics and computer-assisted conformational modeling, the initial lead A was evolved into a series of dihydrobenzofuran derivatives 3 as potent GPR119 agonists. This Letter describes the optimization of general structure 3, including the substituent(s) on dihydrobenzofuran, the R(1) attachment on right-hand piperidine nitrogen, and the left-hand piperidine/piperazine and its attachment R(2). The efforts led to the identification of compounds 13c and 24 as potent human GPR119 modulators with favorable metabolic stability, ion channel activity, and PXR profiles. PMID:24755425

Ye, Xiang-Yang; Morales, Christian L; Wang, Ying; Rossi, Karen A; Malmstrom, Sarah E; Abousleiman, Mojgan; Sereda, Larisa; Apedo, Atsu; Robl, Jeffrey A; Miller, Keith J; Krupinski, John; Wacker, Dean A

2014-06-01

318

Inhibitory Effect of the New Orally Active CCR4 Antagonist K327 on CCR4+CD4+ T Cell Migration into the Lung of Mice with Ovalbumin-Induced Lung Allergic Inflammation  

Microsoft Academic Search

CC chemokine receptor 4 (CCR4) is expressed on Th2 cells, found in inflamed tissues of allergic diseases, and is therefore suspected to be involved in the pathogenesis of allergic diseases by controlling Th2 cell migration into inflamed tissues. The aim of the present study was to investigate the inhibitory effect of a selective CCR4 antagonist, K327 [6-cyclopropancarbonyl-4-(2,4-dichlorobenzylamino)-2-(4-[2-(piperidin-1-yl)ethyl] piperazin-1-yl)-7,8-dihydro-5H-pyrido (4,3-d)pyrimidine], on

Takashi Sato; Masato Komai; Miho Iwase; Katsuya Kobayashi; Harunobu Tahara; Etsuo Ohshima; Hitoshi Arai; Ichiro Miki

2009-01-01

319

Drug-induced parkinsonism: cinnarizine and flunarizine are potent uncouplers of the vacuolar H +ATPase in catecholamine storage vesicles  

Microsoft Academic Search

Cinnarizine (1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine) and its di-fluorinated derivative flunarizine inhibit the MgATP-dependent generation of a transmembrane proton electrochemical gradient in chromaffine granule ghosts. The concentrations giving 50% inhibition (IC50) of the MgATP-dependent generation of the pH-gradient were 5.9±0.6 ?M (n=6) and 3.0±0.3 ?M (n=5) for cinnarizine and flunarizine, respectively. The IC50 values for inhibiting the generation of the membrane potential were even

Ole Terland; Torgeir Flatmark

1999-01-01

320

Diamidines versus Monoamidines as Anti-Pneumocystis Agents: An in vivo Study  

PubMed Central

Some compounds articulated around a piperazine or an ethylenediamine linker have been evaluated in vitro to determine their activity in the presence of a 3T6 fibroblast cell line and an axenic culture of Pneumocystis carinii, respectively. The most efficient antifungal derivatives, namely N,N?-bis(benzamidine-4-yl)ethane-1,2-diamine (compound 6, a diamidine) and N-(benzamidine-4-yl)-N?-phenylethane-1,2-diamine (compound 7, a monoamidine), exhibited no cytotoxicity and were evaluated in vivo in a rat model. Only the diamidine 6 emerged as a promising hit for further studies. PMID:24276317

Stanicki, Dimitri; Pottier, Muriel; Gantois, Nausicaa; Pincon, Claire; Forge, Delphine; Mahieu, Isabelle; Boutry, Sebastien; Vanden Eynde, Jean Jacques; Martinez, Anna; Dei-Cas, Eduardo; Aliouat, El-Moukhtar

2013-01-01

321

Hydrothermal synthesis and characterization of a new vanadyl sulfate compound: crystal structure of [V(IV)OSO 4(H 2O) 4]·SO 4·[H 2N(C 2H 4) 2NH 2  

Microsoft Academic Search

The hydrothermal reaction of a mixture of vanadylacetylacetonate-VO(acac)2, Na2SO4, piperazine, and diluted H2SO4 at 160°C gives a blue colored solution which yields rectangular blue crystals of [V(IV)OSO4(H2O)4]·SO4·[H2N(C2H4)2NH2] (1) in a 60% yield. Complex 1 is a new organic–inorganic compound: a vanadyl sulfate cocrystallized with organic species. The structure of 1 consists of layers of [V(IV)OSO4(H2O)4] separated by SO4?2? and doubly

M. Ishaque Khan; Sabri Cevik; Robert J Doedens

1999-01-01

322

Improved hydrogen ion buffering of media for the culture of freshwater algae  

Microsoft Academic Search

Six hydrogen ion buffers, piperazine-N, N?-bis (2-ethanesulphonic acid) (PIPES), N(-2-acetamido)-2-aminoethanesulphonic acid (ACES), N, N-bis (2-hydroxyethyl)-2-aminoethanesulphonic acid (BES), N-tris (hydroxymethyl)-methyl-2-aminoethanesulphonic acid (TES), N-2-hydroxyethylpiperazine-N?-2-ethanesulphonic acid (HEPES) and N-tris (hydroxymethyl) methylglycine (TRICINE), employed at 0·02 m concentration in freshwater media at their p values, were found to have no adverse effects on the growth rates of Oscillatoria redekei van Goor, Chlorella vulgaris Beij.

R. V. Smith; R. H. Foy

1974-01-01

323

Pharmacological characterization of a novel phosphodiesterase type 5 (PDE5) inhibitor lodenafil carbonate on human and rabbit corpus cavernosum  

Microsoft Academic Search

Nitrergic nerves and endothelial cells release nitric oxide (NO) in the corpus cavernosum, a key mediator that stimulates soluble guanylyl cyclase to increase cGMP levels causing penile erection. Phosphodiesterase 5 (PDE5) inhibitors, such as sildenafil, prolong the NO effects by inhibiting cGMP breakdown. Here, we report a novel PDE5 inhibitor, lodenafil carbonate, (Bis-(2-{4-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-benzenesulfonyl]piperazin-1-yl}-ethyl)carbonate) that is a dimer of lodenafil. We

Haroldo A. Toque; Cleber E. Teixeira; Raquel Lorenzetti; Cristina E. Okuyama; Edson Antunes; Gilberto De Nucci

2008-01-01

324

Determining the subjective effects of TFMPP in human males  

Microsoft Academic Search

Rationale  Trifluoromethylphenyl piperazine (TFMPP) is an active constituent of a relatively new group of recreational drugs known as\\u000a ‘party pills’. TFMPP has been anecdotally reported to induce mild psychedelic effects similar to lysergic acid diethylamide\\u000a and psilocybin. There has been no research about the subjective effects of TFMPP in humans.\\u000a \\u000a \\u000a \\u000a \\u000a Objectives  This study aimed to investigate the subjective effects of TFMPP in

Reem K. Jan; Joanne C. Lin; HeeSeung Lee; Janie L. Sheridan; Rob R. Kydd; Ian J. Kirk; Bruce R. Russell

2010-01-01

325

Determining the subjective and physiological effects of BZP combined with TFMPP in human males  

Microsoft Academic Search

Rationale  ‘Party Pills’ containing benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) have been used in a recreational\\u000a context since the 1990s and, prior to April 2008, were legally available in New Zealand. Taken together, they have been reported\\u000a to produce a ‘high’ similar to that produced by 3,4-methylenedioxymethamphetamine (MDMA).\\u000a \\u000a \\u000a \\u000a \\u000a Objectives  There has been little research on the subjective effects of piperazines in humans. The

Joanne C. Lin; Reem K. Jan; HeeSeung Lee; Maree-Ann Jensen; Rob R. Kydd; Bruce R. Russell

2011-01-01

326

Determination of anthelmintic activity of the leaf and bark extract of tamarindus indica linn.  

PubMed

The aim of the present study was to evaluate the anthelmintic activity of ethanolic and aqueous extract of leaves and bark of Tamarindus indica Linn using Pheretima posthuma and Tubifex tubifex as test worms. The time of paralysis and time of death were studied and the activity was compared with piperazine citrate as reference standard. The alcohol and aqueous extract of bark of Tamarindus indica exhibited significant anthelmintic activity as evidenced by decreased paralyzing time and death time. The results thus support the use of Tamarindus indica as an anthelmintic agent. PMID:22131633

Das, S S; Dey, Monalisha; Ghosh, A K

2011-01-01

327

Determination of Anthelmintic Activity of the Leaf and Bark Extract of Tamarindus Indica Linn  

PubMed Central

The aim of the present study was to evaluate the anthelmintic activity of ethanolic and aqueous extract of leaves and bark of Tamarindus indica Linn using Pheretima posthuma and Tubifex tubifex as test worms. The time of paralysis and time of death were studied and the activity was compared with piperazine citrate as reference standard. The alcohol and aqueous extract of bark of Tamarindus indica exhibited significant anthelmintic activity as evidenced by decreased paralyzing time and death time. The results thus support the use of Tamarindus indica as an anthelmintic agent. PMID:22131633

Das, S. S.; Dey, Monalisha; Ghosh, A. K.

2011-01-01

328

Actions of ?2 adrenoceptor ligands at ?2A and 5HT1A receptors: the antagonist, atipamezole, and the agonist, dexmedetomidine, are highly selective for ?2A adrenoceptors  

Microsoft Academic Search

This study examined the activity of chemically diverse ?2 adrenoceptor ligands at recombinant human (h) and native rat (r) ?2A adrenoceptors as compared with 5-HT1A receptors. First, in competition binding experiments at h?2A and h5-HT1A receptors expressed in CHO cells, several compounds, including the antagonists 1-(2-pyrimidinyl)piperazine (1-PP), (?)-idazoxan,\\u000a benalfocin (SKF 86466), yohimbine and RX 821,002, displayed preference for h?2A versus

Adrian Newman-Tancredi; Jean-Paul Nicolas; Valérie Audinot; Samantha Gavaudan; Laurence Verrièle; Manuelle Touzard; Christine Chaput; Nelly Richard; Mark J. Millan

1998-01-01

329

Rapid method for isolating targeted organic chemicals from biological matrices  

SciTech Connect

The initial development is reported for a novel countercurrent filtration/dialysis and solid phase extractant system for the rapid isolation of low molecular weight target compounds from biological media. Except for piperazine (a highly water-soluble drug), recoveries of 50 - 95% were achieved for chemical warfare agent simulants and anthelmintic drugs extracted from meat, grain, or milk. The results suggest the potential for broad applications to complex samples such as environmental media and physiological specimens which traditionally require extensive fractionation prior to analysis.

Caton, J.E.; Griest, W.H.; Watson, A.P.; Buchanan, M.V. (Oak Ridge National Lab., TN (United States)); Hazen, K.H. (Univ. of Iowa, Iowa City, IA (United States))

1994-01-01

330

5HT 1A receptor antagonist p-MPPI attenuates acute ethanol effects in mice and rats  

Microsoft Academic Search

The effect of a selective 5-HT1A antagonist, 4-(2?-methoxy-)phenyl-1-[2?-(N-2??-pyridinyl)-p-iodobenzamino-]ethyl-piperazine (p-MPPI), on acute ethanol-induced hypothermia, sleep and suppression of acoustic startle reflex in C3H\\/He mice and Wistar rats was studied. Administration of p-MPPI at the doses of 0.4, 0.7 and 1.0 mg\\/kg reduced in a dose-dependent manner the ethanol-induced hypothermia and the sleep time and attenuated the ethanol-induced decrease of acoustic startle

Nina K. Popova; Elena A. Ivanova

2002-01-01

331

Simultaneous quantitative determination of amphetamines, ketamine, opiates and metabolites in human hair by gas chromatography/mass spectrometry.  

PubMed

A gas chromatography/mass spectrometry (GC/MS) method was developed and validated for the determination of common drugs of abuse in Asia. The method was able to simultaneously quantify amphetamines (amphetamine; AP, methamphetamine; MA, methylenedioxy amphetamine; MDA, methylenedioxymeth mphetamine; MDMA, methylenedioxy ethylamphetamine; MDEA), ketamine (ketamine; K, norketamine; NK), and opiates (morphine; MOR, codeine; COD, 6-acetylmorphine; 6-AM) in human hair. Hair samples (25 mg) were washed, cut, and incubated overnight at 25 degrees C in methanol/trifluoroacetic acid (methanol/TFA). The samples were extracted by solid-phase extraction (SPE), derivatized using heptafluorobutyric acid anhydride (HFBA) at 70 degrees C for 30 min, and the derivatives were analyzed by electron ionization (EI) GC/MS in selected ion monitoring mode. Confirmation was accomplished by comparing retention times and the relative abundances of selected ions with those of standards. Deuterated analogs of the analytes were used as internal standards for quantification. Calibration curves for ten analytes were established in the concentration range 0.1-10 ng/mg with high correlation coefficients (r2 > 0.999). The intra-day and inter-day precisions were within 12.1% and 15.8%, respectively. The intra-day and inter-day accuracies were between -8.7% and 10.7%, and between -5.9% and 13.8%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 0.03 and 0.05 ng/mg for AP, MA, MDA, MDMA and MDEA; 0.05 and 0.08 ng/mg for K, NK, MOR and COD; and 0.08 and 0.1 ng/mg for 6-AM. The recoveries were above 88.6% for all the compounds, except K and NK which were in the range of 71.7-72.7%. Eight hair samples from known polydrug abusers were examined by this method. These results show that the method is suitable for broad-spectrum drug testing in a single hair specimen. PMID:18288687

Wu, Ya-Hsueh; Lin, Keh-Liang; Chen, Su-Chin; Chang, Yan-Zin

2008-01-01

332

1-Piperonylpiperazinium 4-nitro-benzoate monohydrate  

PubMed Central

In the title hydrated salt [systematic name: 1-(1,3-benzodioxol-5-ylmeth­yl)piperazin-1-ium 4-nitro­benzoate monohydrate], C12H17N2O2 +·C7H4NO4 ?·H2O, the piperazinium ring of the cation adopts a slightly distorted chair conformation. The piperonyl and piperazine rings are rotated with respect to each other with an N—C—C—C torsion angle of 45.6?(2)°. In the anion, the nitro group is almost coplanar with the adjacent benzene ring, forming a dihedral angle of only 3.9?(4)°. In the crystal, the cations, anions and water mol­ecules are linked through N—H?O and O—H?O hydrogen bonds into chains along the a axis. In addition, weaker inter­molecular C—H?O inter­actions are also observed within the chains. The anions form centrosymmetric couples through ?-stacking inter­actions, with an inter­centroid distance of 3.681?(4)?Å between the benzene rings. PMID:24764985

Kavitha, Channappa N.; Kaur, Manpreet; Anderson, Brian J.; Jasinski, Jerry P.; Yathirajan, H. S.

2014-01-01

333

Buffers in daphnid culture and bioassay  

SciTech Connect

When an algal diet is employed, or precipitation of dissolved inorganics during autoclaving is likely, or test circumstances introduce pH changes, addition of a buffer to daphnid culture or bioassay media is appropriate. Glycylglycine, employed in this research for 20 years, is unsuitable for general use because it required microbe-free cultures. In contrast, n-hydroxyethyl piperazine-n-2-propane sulfonic acid (HEPPSO) and N-2-hydroxyethyl piperazine-N{prime}-2-ethane sulfonic acid (HEPES) offer safe and effective pH control at 300 ppm for animals, 400 ppm for algae (weight excludes Na), with no requirement for microbe-free cultures. No negative effects on fecundity, monitored in both single and multigeneration tests, or on vigor, measured by acute bioassay performance, were observed. The 48-h LC50 for glycylglycine is approximately 4,500 ppm. No deaths occur at or below 10,000 ppm of either HEPES or HEPPSO. When bioassayed against zinc (as chloride), animals reared in cultures buffered by HEPES, HEPPSO, or glycylglycine and tested in unfed acute bioassays performed similarly, allowing 100% survival in 1,000 ppb in 48 h with an CL50 of approximately 1,750 ppb.

Keating, K.I.; Caffrey, P.B.; Dagbusan, B.C. [Rutgers-the State Univ., New Brunswick, NJ (United States). Dept. of Environmental Science

1996-03-01

334

Synthesis and anticonvulsant properties of new acetamide derivatives of phthalimide, and its saturated cyclohexane and norbornene analogs.  

PubMed

The synthesis and anticonvulsant properties of new piperazine or morpholine acetamides derived from 2-(1,3-dioxoisoindolin-2-yl)-, 2-(1,3-dioxo-3a,4,5,6,7,7a-hexahydroisoindol-2-yl-) and (3,5-dioxo-4-azatricyclo[5.2.1.0(2,6)]dec-8-en-4-yl)-acetic acid were described. Initial anticonvulsant screening was performed using maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizures tests. The neurotoxicity was determined applying the minimal motor impairment rotarod test. The in vivo results revealed that numerous compounds were effective in the MES screen. The most active was 2-{2-[4-(4-fluorophenyl)piperazin-1-yl]-2-oxoethyl}isoindoline-1,3-dione (12) that revealed protection in the electrically induced seizures at a dose of 30 mg/kg and 100 mg/kg 0.5 h and 4 h after i.p. administration in mice respectively. This molecule given orally in rats at a dose of 30 mg/kg was more potent than reference anticonvulsant--phenytoin. PMID:21840629

Kami?ski, Krzysztof; Obniska, Jolanta; Wiklik, Beata; Atamanyuk, Dmytro

2011-09-01

335

Blood pH optrode based on evanescent waves and refractive index change  

NASA Astrophysics Data System (ADS)

Sensing pH in blood with an silica multimode optical fiber. This sensor is based on evanescent wave absorption and measures the change of the refractive index and absorption in a cladding made of a biocompatible Polymer. In contrast to many existing fiber optical sensors which are based upon different dyes or florescent material to sense the pH, here presents a solution where a part of the cladding is replaced with a Poly (?-amino ester) made of 1.4-Butanediol diacrylate, Piperazine, and Trimethylolpropane Triacrylate. Piperazine has the feature of changing its volume by swelling or shrinking in response to the pH level. This paper utilizes this dimension effect and measure the refractive index and the absorption of the cladding in respect to different pH-levels. The alteration of refractive index also causes a change in the absorption and therefore the output power changes as a function of the pH level. The sensor is sensitive to pH in a wide spectral range and light absorbency can be observed for wavelengths ranging from UV to far IR.

Hammarling, Krister; Hilborn, Jöns; Nilsson, Hans-Erik; Manuilskiy, Anatoliy

2014-02-01

336

Selective naked-eye detection of Hg²? through an efficient turn-on photoinduced electron transfer fluorescent probe and its real applications.  

PubMed

A simple molecular fluorescent probe 5 has been designed and synthesized by appending anthracene and benzhydryl moieties through a piperazine bridge. The probe upon interaction with different metal ions showed high selectivity and sensitivity (2 ppb) for Hg(2+) through fluorescence "turn-on" response in HEPES buffer. The significant fluorescence enhancement (~10-fold) is attributable to PET arrest due to complexation with nitrogen atoms of the piperazine unit and Hg(2+) in 1:2 stoichiometry, in which a naked-eye sensitive fluorescent blue color of solution changed to a blue-green (switched-on). As a proof of concept, promising prospects for application in environmental and biological sciences 5 have been utilized to detect Hg(2+) sensitively in real samples, on cellulose paper strips, in protein medium (like BSA), and intracellularly in HeLa cells. Moreover, the optical behavior of 5 upon providing different chemical inputs has been utilized to construct individual logic gates and a reusable combinational logic circuit. The combinational circuit (switch ON mode; OR logic gate) is easily resettable to the original position (switch OFF mode; INHIBIT logic gate) by applying reset chemical inputs (OH(-) and PO4(3-)) with great reproducibility. PMID:25098642

Srivastava, Priyanka; Razi, Syed S; Ali, Rashid; Gupta, Ramesh C; Yadav, Suresh S; Narayan, Gopeshwar; Misra, Arvind

2014-09-01

337

Cr(III), Fe(III) and Co(III) complexes of tetradentate (ONNO) Schiff base ligands: Synthesis, characterization, properties and biological activity  

NASA Astrophysics Data System (ADS)

A series of metal complexes were synthesized from equimolar amounts of Schiff bases: 1,4-bis[3-(2-hydroxy-1-naphthaldimine)propyl]piperazine (bappnaf) and 1,8-bis[3-(2-hydroxy-1-naphthaldimine)- p-menthane (damnaf) with metal chlorides. All of synthesized compounds were characterized by elemental analyses, spectral (UV-vis, IR, 1H- 13C NMR, LC-MS) and thermal (TGA-DTA) methods, magnetic and conductance measurements. Schiff base complexes supposed in tetragonal geometry have the general formula [M(bappnaf or damnaf)]Cl· nH 2O, where M = Cr(III), Co(III) and n = 2, 3. But also Fe(III) complexes have octahedral geometry by the coordination of two water molecules and the formula is [Fe(bappnaf or damnaf)(H 2O) 2]Cl. The changes in the selected vibration bands in FT-IR indicate that Schiff bases behave as (ONNO) tetradentate ligands and coordinate to metal ions from two phenolic oxygen atoms and two azomethine nitrogen atoms. Conductance measurements suggest 1:1 electrolytic nature of the metal complexes. The synthesized compounds except bappnaf ligand have the antimicrobial activity against the bacteria: Escherichia coli (ATCC 11230), Yersinia enterocolitica (ATCC 1501), Bacillus magaterium (RSKK 5117), Bacillus subtilis (RSKK 244), Bacillus cereus (RSKK 863) and the fungi: Candida albicans (ATCC 10239). These results have been considerably interest in piperazine derivatives due to their significant applications in antimicrobial studies.

Keskio?lu, Eren; Gündüzalp, Ayla Balaban; Çete, Servet; Hamurcu, Fatma; Erk, Birgül

2008-08-01

338

Ferrous iron uptake by Bifidobacterium bifidum var. pennsylvanicus: the effect of metals and metabolic inhibitors.  

PubMed

Ferrous iron uptake studies in Bifidobacterium bifidum var. pennsylvanicus were carried out in a well-defined salt solution termed "modified Hanks solution" at both high iron concentrations (LAFIUS conditions) and low concentrations (HAFIUS conditions). Various divalent metals, Mn2+, Zn2+, Ni2+ and Cu2+, inhibited iron uptake under HAFIUS conditions in a non-competitive manner, and in a pseudo-competitive manner under LAFIUS conditions. Cr2+ had no effect. Co2+ inhibited iron uptake competitively under HAFIUS conditions. Metabolic affectors that inhibited iron uptake both under HAFIUS and LAFIUS conditions were: tetraphenylphosphonium chloride, diethylstilbesterol, vanadate, carbonylcyanide-m-chlorophenyl-hydrazone, and a mixture of valinomycin and nigericin. Substances that stimulated iron uptake were KCl, valinomycin, and nigericin. Iron uptake under LAFIUS conditions in piperazine-buffered modified Hanks solution was higher than that in the acetate-buffered solution, and acetate inhibited iron uptake in the piperazine buffer. HAFIUS showed no difference. It is concluded that iron uptake in bifidobacteria is driven by an ATPase-dependent proton-motive force and that both the pH gradient and membrane potential are involved in this process. Mn2+, Zn2+, Ni2+, and Cu2+ may be transported via LAFIUS, but not HAFIUS. HAFIUS may transport only Co2+ in addition to Fe2+. PMID:3038634

Bezkorovainy, A; Solberg, L; Poch, M; Miller-Catchpole, R

1987-01-01

339

Small molecule disruptors of the glucokinase-glucokinase regulatory protein interaction: 4. Exploration of a novel binding pocket.  

PubMed

Structure-activity relationship investigations conducted at the 5-position of the N-pyridine ring of a series of N-arylsulfonyl-N'-2-pyridinyl-piperazines led to the identification of a novel bis-pyridinyl piperazine sulfonamide (51) that was a potent disruptor of the glucokinase-glucokinase regulatory protein (GK-GKRP) interaction. Analysis of the X-ray cocrystal of compound 51 bound to hGKRP revealed that the 3-pyridine ring moiety occupied a previously unexplored binding pocket within the protein. Key features of this new binding mode included forming favorable contacts with the top face of the Ala27-Val28-Pro29 ("shelf region") as well as an edge-to-face interaction with the Tyr24 side chain. Compound 51 was potent in both biochemical and cellular assays (IC50=0.005 ?M and EC50=0.205 ?M, respectively) and exhibited acceptable pharmacokinetic properties for in vivo evaluation. When administered to db/db mice (100 mg/kg, po), compound 51 demonstrated a robust pharmacodynamic effect and significantly reduced blood glucose levels up to 6 h postdose. PMID:25001129

Hong, Fang-Tsao; Norman, Mark H; Ashton, Kate S; Bartberger, Michael D; Chen, Jie; Chmait, Samer; Cupples, Rod; Fotsch, Christopher; Jordan, Steven R; Lloyd, David J; Sivits, Glenn; Tadesse, Seifu; Hale, Clarence; St Jean, David J

2014-07-24

340

Cinnarizinium bis-(p-toluene-sulfonate) dihydrate  

PubMed Central

The asymmetric unit of the title salt [systematic name: 1-benzhydryl-4-cinnamylpiperazine-1,4-diium bis­(p-toluene­sulfonate) dihydrate], C26H30N2 2+·2C7H7O3S?·2H2O, consists of a diprotonated cinnarizinium cation hydrogen bonded through two water mol­ecules to two independent p-toluene­sulfonate anions, one which is disordered over two sets of sites in a 0.793?(3):0.207?(3) ratio. In the cation, the piperazine ring adopts a chair configuration and contains two positively charged N atoms with quarternery character. The dihedral angle between the two benzene rings in the benzhydr­yl group is 71.8?(1)°. The benzene ring flanked opposite the piperazine ring is twisted by 75.9?(9) and 8.8?(3)° from these two benzene rings. In the crystal, the [N—H?Owater—H?O( S)]2 hydrogen-bonded asymmetric unit is connected by further O—H?O hydrogen bonds linking the components into chains along [100]. PMID:23634038

Kavitha, C. N.; Butcher, Ray J.; Jasinski, Jerry P.; Yathirajan, H. S.; Dayananda, A. S.

2013-01-01

341

Cinnarizinium dipicrate  

PubMed Central

In the cinnarizinium dication of the title compound {systematic name: 1-diphenyl­methyl-4-[(2E)-3-phenyl­prop-2-en-1-yl]piperazine-1,4-diium bis­(2,4,6-trinitro­phenolate)}, C26H30N2 2+·2C6H2N3O7 ?, the piperazine group is protonated at both N atoms and adopts a slightly distorted chair conformation. Strong N—H?Ohy­droxy cation–anion hydrogen bonds link the dication and two anions. In the cation, the (2E)-3-phenyl­prop-2-en-1-yl fragment is disordered over two positions in a ratio of 0.586?(4): 0.414?(4). Two nitro groups in one anion and three in the other one demonstrate rotational disorder. The crystal packing is stabilized by weak inter­molecular ?–? [centroid–centroid distances = 3.844?(7), 3.677?(9), 3.825?(5), 3.634?(2) and 3.729?(7)?Å], C—H?? and C—H?O inter­actions. PMID:21523154

Jasinski, Jerry P.; Butcher, Ray J.; Siddegowda, M. S.; Yathirajan, H. S.; Chidan Kumar, C. S.

2011-01-01

342

Zero-valent iron mediated degradation of ciprofloxacin - Assessment of adsorption, operational parameters and degradation products.  

PubMed

The zero-valent iron (ZVI) mediated degradation of the antibiotic ciprofloxacin (CIP) was studied under oxic condition. Operational parameters such as ZVI concentration and initial pH value were evaluated. Increase of the ZVI concentration from 1 to 5gL(-1) resulted in a sharp increase of the observed pseudo-first order rate constant of CIP degradation, reaching a plateau at around 10gL(-1). The contribution of adsorption to the overall removal of CIP and dissolved organic carbon (DOC) was evaluated after a procedure of acidification to pH 2.5 with sulfuric acid and sonication for 2min. Adsorption increased as pH increased, while degradation decreased, showing that adsorption is not important for degradation. Contribution of adsorption was much more important for DOC removal than for CIP. Degradation of CIP resulted in partial defluorination since the fluoride measured corresponded to 34% of the theoretical value after 120min of reaction. Analysis by liquid chromatography coupled to mass spectrometry showed the presence of products of hydroxylation on both piperazine and quinolonic rings generating fluorinated and defluorinated compounds as well as a product of the piperazine ring cleavage. PMID:25150686

Perini, João Angelo de Lima; Silva, Bianca Ferreira; Nogueira, Raquel F Pupo

2014-12-01

343

Affinity of An(VI) for N4-Tetradentate Donor Ligands: Complexation of the Actinyl(VI) Ions with N4-Tetradentate Ligands  

SciTech Connect

In this report the affinity of four N4-tetradentate ligands that incorporate the 2- methylpyridyl functionality with hexavalent actinides (AnO2+2 ) has been investigated in methanol solution. The ligands studied include N,N*-bis(2-methylpyridyl)diaminoethane (BPMDAE), N,N-bis(2-methylpyridyl)-1,3-diaminopropane (BPMDAP), N,N*-bis(2-pyridylmethyl) piperazine (BPMPIP), and trans-N,N-bis(2-pyridylmethyl)-1,2-diaminocyclohexane (BPMDAC). Conditional stability constants describing the strength of the interaction were determined by UV-visible spectrophotometry. The log10K101 values for both U(VI) and Pu(VI) are comparable and show the same trend of stability with ligand structure. Dinuclear complexes are also indicated as being important. The log10K201 values for Pu(VI) complexation with the N4-ligands are identical for the four ligands (within experimental error), indicating that the structure of the ligand backbone has little effect on the stability of the (PuO2)2L2+ complex. The exception to this trend is the behavior of N,N*- bis(2-pyridylmethyl)piperazine (BPMPIP) with Pu(VI). This ligand displays a tendency to reduce Pu(VI) within the experimental time frame of 45 minutes. BPMPIP is the only ligand tested that contains tertiary amines in the ligand backbone. The decomposition of BPMPIP by Pu(VI) suggests a susceptibility of tertiary amines to oxidative degradation.

Ogden, Mark; Sinkov, Sergey I.; Lumetta, Gregg J.; Nash, Kenneth L.

2012-05-01

344

A bisazobenzene crosslinker that isomerizes with visible light  

PubMed Central

Summary Background: Large conformational and functional changes of azobenzene-modified biomolecules require longer azobenzene derivatives that undergo large end-to-end distance changes upon photoisomerization. In addition, isomerization that occurs with visible rather than UV irradiation is preferred for biological applications. Results: We report the synthesis and characterization of a new crosslinker in which a central piperazine unit links two azobenzene chromophores. Molecular modeling indicates that this crosslinker can undergo a large change in end-to-end distance upon trans,trans to cis,cis isomerization. Photochemical characterization indicates that it does isomerize with visible light (violet to blue wavelengths). However, the thermal relaxation rate of this crosslinker is rather high (?½ ~ 1 s in aqueous buffer at neutral pH) so that it is difficult to produce large fractions of the cis,cis-species without very bright light sources. Conclusion: While cis-lifetimes may be longer when the crosslinker is attached to a biomolecule, it appears the para-piperazine unit may be best suited for applications where rapid thermal relaxation is required. PMID:23359333

Samanta, Subhas; Qureshi, Harris I

2012-01-01

345

Development and validation of a single LC-MS/MS assay following SPE for simultaneous hair analysis of amphetamines, opiates, cocaine and metabolites.  

PubMed

The two major challenges in hair analysis are the limited amount of samples usually available and the low targeted concentrations. To overcome these limitations, a liquid chromatography-electrospray-tandem mass spectrometry method (LC-ESI-MS/MS) allowing the simultaneous analysis of 17 amphetamines (amphetamine, BDB, m-CPP, dexfenfluramine, DOB, DOM, ephedrine, MBDB, MDA, MDEA, MDMA, methamphetamine, methylphenidate, 4-MTA, norephedrine, norfenfluramine and PMA), 5 opiates (morphine, codeine, heroin, ethylmorphine, and 6AM), cocaine and 5 metabolites [ecgonine methyl ester (EME), benzoylecgonine (BZE), anhydroecgonine methyl ester (AME), cocaethylene, and norcocaine] has been developed. The validation procedure included linearity, intra-day and inter-day variability and accuracy for 5 days (5 replicates at 3 concentration levels). Proficiency studies were used to check the accuracy of the method. As a result, all amphetamines, opiates and cocaine derivatives were satisfactory identified by 2 MRM transitions in 15 min. Calibration curves were performed by a quadratic 1/X weighted regression. The calibration model fits from 0.05 to 10 ng/mg. The limits of detection (LODs) range between 0.005 and 0.030 ng/mg. Precision has been checked by intra-day and inter-day RSD, and associated relative bias, which were lower than 25% for the limits of quantifications (LOQs) and lower than 20% for the other levels tested. This method was routinely applied to hair samples: two positive results of adult drug addicts are presented. PMID:24378313

Imbert, L; Dulaurent, S; Mercerolle, M; Morichon, J; Lachâtre, G; Gaulier, J-M

2014-01-01

346

Comparing selective H/sub 2/S removal methods in CO/sub 2/ floods  

SciTech Connect

Presents case studies of processes chosen for H/sub 2/S removal, focusing on decision-driving criteria. Emphasizes that the criteria (ethane recovery incentive, fuel gas cost, capital available, and use of existing NGL plant) are not the only important variables to be considered in determining process selections and overall facility designs. H/sub 2/S content of the associated gas stream is typically about 3% at the beginning of the project, and is projected to decrease to about 0.5% at some point in time during the flood. Processes chosen for study are Benfield or Sulfinol gas treating with MDEA selective H/sub 2/S removal from CO/sub 2/ product stream; sour NGL recovery pretreatment plus Selexol selective H/sub 2/S removal from processed gas stream; Ryan/Holmes cryogenic fractionation processes plus DEA NGL product treating; and Benfield gas treating followed by Selexol selective H/sub 2/S removal from CO/sub 2/ product stream. Concludes that the variables discussed here seem to be the decision-driving forces that change most frequently between projects in this area.

Laengrich, A.; Carlisle, K.; Harmon, C.

1982-08-01

347

Critical review, comparative evaluation, cost update, and baseline data development services in oil shale mining, in-situ liquefaction, and above ground retorting processes from the environmental, permitting, and licensing viewpoints. Volume III. Emission source identification and source-specific pollution control applications. Part 1  

SciTech Connect

The present volume is the third major deliverable of the title study. The document accomplished two objectives: (1) It identifies all major emission sources within an integrated flowsheet of oil shale operations encompassing mining, preparation, retorting, and upgrading; and (2) It delineates the logic process for selecting and instigating source-specific pollution controls, selected among all currently commercially available options. Specific pollutants dealt with in the present Volume III are sulfur species, (H/sub 2/S and SO/sub 2/ primarily), particulates, fugitive dust, and arsenic species. The present Volume III is divided into two separate Parts. Part 1 covers: (1) Sulfur species (H/sub 2/S and SO/sub 2/); (2) Particulates and fugitive dust; and (3) Arsenic. Retort off-gas control processes considered include: MDEA; Benfield Process; Physical absorption systems; Sulfinol Process; and The Holmes-Stretford Process. Processes considered for the control of SO/sub 2/ in flue gas are: Wellman-Lord Process; Limestone Slurry Process; Lime Slurry Process; Chiyoda Thoroughbred 121; Lime Slurry Spray Dryer/Fabric Filter Process; Resox Process; Magnesia Slurry Process; Double Alkali Process; Citrate/Phosphate Absorption Process; Ammonia-Ammonium Bisulfite Process; IFP Process; Activated Carbon Process; Catalytic Oxidation processes; Shell/UOP Copper Oxide Process; and Davy S-H Process. For removal of dusts and particulates, cyclones, electrostatic precipitators, afterburners, scrubbers, mist eliminators, fabric filters and sonic agglomeration are evaluated. Wastewater, off-gas, and product oil controls for arsenic removal are also presented. (DMC)

Not Available

1981-05-01

348

Sulften system commercialized  

SciTech Connect

Operation of a Sulften system resulted in reduced fuel gas usage, reduced regeneration steam consumption, increased CO/sub 2/ slip, and increased capacity available in the sulfur recovery unit (SRU) compared with performance of a 25%-MDEA plant. Vent gas contained less than 10 ppmv H/sub 2/S, which allows for direct atmospheric discharge. The system performed as well as, if not better than, conventional amine-based tail gas treating units (TGTUS) while producing a vent gas of superior environmental characteristics. Economics of the operation resulted in a simple payout of approximately one year or a declining cash flow return on investment of 64%. Attainable sulfur recoveries of Claus-Based SRUS (up to 97%) are inadequate to meet emission regulations. Therefore, TGTUS have been developed which, when combined with a SRU achieve recoveries in excess of 99.9%. Two types of TGTUS are commercially available: tail gas incineration processes oxidize (incinerate) sulfur species in SRU tail gas and react resulting SO/sub 2/ to remove it from vent gas; tail gas reduction processes reduce sulfur species in SRU tail gas and react produced H/sub 2/S with compounds that remove it from vent gas. Vent gas from amine-based tail gas reduction processes usually requires incineration to meet the 10 ppmv H/sub 2/S limit.

Tragitt, G.N.; Armstrong, T.R.; Bourdon, J.C.; Sigmund, P.W.

1986-02-01

349

Hybrid Membrane/Absorption Process for Post-combustion CO2 Capture  

SciTech Connect

This report summarizes scientific/technical progress made for bench-scale membrane contactor technology for post-combustion CO2 capture from DOE Contract No. DE-FE-0004787. Budget Period 1 (BP1) membrane absorber, Budget Period 2 (BP2) membrane desorber and Budget Period 3 (BP3) integrated system and field testing studies have been completed successfully and met or exceeded the technical targets (? 90% CO2 removal and CO2 purity of 97% in one membrane stage). Significant breakthroughs are summarized below: BP1 research: The feasibility of utilizing the poly (ether ether ketone), PEEK, based hollow fiber contractor (HFC) in combination with chemical solvents to separate and capture at least 90% of the CO2 from simulated flue gases has been successfully established. Excellent progress has been made as we have achieved the BP1 goal: ? 1,000 membrane intrinsic CO2 permeance, ? 90% CO2 removal in one stage, ? 2 psi gas side pressure drop, and ? 1 (sec)-1 mass transfer coefficient. Initial test results also show that the CO2 capture performance, using activated Methyl Diethanol Amine (aMDEA) solvent, was not affected by flue gas contaminants O2 (~3%), NO2 (66 ppmv), and SO2 (145 ppmv). BP2 research: The feasibility of utilizing the PEEK HFC for CO2-loaded solvent regeneration has been successfully established High CO2 stripping flux, one order of magnitude higher than CO2 absorption flux, have been achieved. Refined economic evaluation based on BP1 membrane absorber and BP2 membrane desorber laboratory test data indicate that the CO2 capture costs are 36% lower than DOE’s benchmark amine absorption technology. BP3 research: A bench-scale system utilizing a membrane absorber and desorber was integrated into a continuous CO2 capture process using contactors containing 10 to 20 ft2 of membrane area. The integrated process operation was stable through a 100-hour laboratory test, utilizing a simulated flue gas stream. Greater than 90% CO2 capture combined with 97% CO2 product purity was achieved throughout the test. Membrane contactor modules have been scaled from bench scale 2-inch diameter by 12-inch long (20 ft2 membrane surface area) modules to 4-inch diameter by 60-inch long pilot scale modules (165 ft2 membrane surface area). Pilot scale modules were tested in an integrated absorption/regeneration system for CO2 capture field tests at a coal-fired power plant (Midwest Generation’s Will County Station located in Romeoville, IL). Absorption and regeneration contactors were constructed utilizing high performance super-hydrophobic, nano-porous PEEK membranes with CO2 gas permeance of 2,000 GPU and a 1,000 GPU, respectively. Field tests using aMDEA solvent achieved greater than 90% CO2 removal in a single stage. The absorption mass transfer coefficient was 1.2 (sec)-1, exceeding the initial target of 1.0 (sec)-1. This mass transfer coefficient is over one order of magnitude greater than that of conventional gas/liquid contacting equipment. The economic evaluation based on field tests data indicates that the CO2 capture cost associated with membrane contactor technology is $54.69 (Yr 2011$)/tonne of CO2 captured when using aMDEA as a solvent. It is projected that the DOE’s 2025 cost goal of $40 (Yr 2011$)/tonne of CO2 captured can be met by decreasing membrane module cost and by utilizing advanced CO2 capture solvents. In the second stage of the field test, an advanced solvent, Hitachi’s H3-1 was utilized. The use of H3-1 solvent increased mass transfer coefficient by 17% as compared to aMDEA solvent. The high mass transfer coefficient of H3-1 solvent combined with much more favorable solvent regeneration requirements, indicate that the projected savings achievable with membrane contactor process can be further improved. H3-1 solvent will be used in the next pilot-scale development phase. The integrated absorption/regeneration process design and high performance membrane contactors developed in the current bench-scale program will be used as the base technology for future pilot-scale development.

Li, Shiguang; Shou, S.; Pyrzynski, Travis; Makkuni, Ajay; Meyer, Howard

2013-12-31

350

Microfluidic chip based nano liquid chromatography coupled to tandem mass spectrometry for the determination of abused drugs and metabolites in human hair.  

PubMed

A microfluidic chip based nano-HPLC coupled to tandem mass spectrometry (nano-HPLC-Chip-MS/MS) has been developed for simultaneous measurement of abused drugs and metabolites: cocaine, benzoylecgonine, cocaethylene, norcocaine, morphine, codeine, 6-acetylmorphine, phencyclidine, amphetamine, methamphetamine, MDMA, MDA, MDEA, and methadone in the hair of drug abusers. The microfluidic chip was fabricated by laminating polyimide films and it integrated an enrichment column, an analytical column and a nanospray tip. Drugs were extracted from hairs by sonication, and the chromatographic separation was achieved in 15 min. The drug identification and quantification criteria were fulfilled by the triple quardropule tandem mass spectrometry. The linear regression analysis was calibrated by deuterated internal standards with all of the R(2) at least over 0.993. The limit of detection (LOD) and the limit of quantification (LOQ) were from 0.1 to 0.75 and 0.2 to 1.25 pg/mg, respectively. The validation parameters including selectivity, accuracy, precision, stability, and matrix effect were also evaluated here. In conclusion, the developed sample preparation method coupled with the nano-HPLC-Chip-MS/MS method was able to reveal the presence of drugs in hairs from the drug abusers, with the enhanced sensitivity, compared with the conventional HPLC-MS/MS. PMID:22281681

Zhu, Kevin Y; Leung, K Wing; Ting, Annie K L; Wong, Zack C F; Ng, Winki Y Y; Choi, Roy C Y; Dong, Tina T X; Wang, Tiejie; Lau, David T W; Tsim, Karl W K

2012-03-01

351

Nitrile-functionalized tertiary amines as highly efficient and reversible SO2 absorbents.  

PubMed

Three different types of nitrile-functionalized amines, including 3-(N,N-diethylamino)propionitrile (DEAPN), 3-(N,N-dibutylamino)propionitrile (DBAPN), and N-methyl-N,N-dipropionitrile amine (MADPN) were synthesized, and their SO2 absorption performances were evaluated and compared with those of hydroxy-functionalized amines such as N,N-diethyl-N-ethanol amine (DEEA), N,N-dibutyl-N-ethanol amine (DBEA), and N-methyl-N,N-diethanol amine (MDEA). Absorption-desorption cycle experiments clearly demonstrate that the nitrile-functionalized amines are more efficient than the hydroxy-functionalized amines in terms of absorption rate and regenerability. Computational calculations with DBEA and DBAPN revealed that DBEA bearing a hydroxyethyl group chemically interacts with SO2 through oxygen atom, forming an ionic compound with a covalently bound OSO2(-) group. On the contrary, DBAPN bearing a nitrile group physically interacts with SO2 through the nitrogen and the hydrogen atoms of the two methylene groups adjacent to the amino and nitrile functionalities. PMID:24291666

Hong, Sung Yun; Kim, Heehwan; Kim, Young Jin; Jeong, Junkyo; Cheong, Minserk; Lee, Hyunjoo; Kim, Hoon Sik; Lee, Je Seung

2014-01-15

352

Development of a method for the analysis of drugs of abuse in vitreous humor by capillary electrophoresis with diode array detection (CE-DAD).  

PubMed

This work presents the development of an analytical method based on capillary electrophoresis with diode array detection for the analysis of drugs of abuse and biotransformation products in vitreous humor. Composition of the background electrolyte, implementation of an online pre-concentration strategy and sample preparation procedures were objects of study. The complete electrophoretic separation of 12 analytes (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), ketamine, cocaine, cocaethylene, lidocaine, morphine, 6-monoacetylmorphine and heroin) and the internal standard N-methyl-1-(3,4-methylenedioxyphenyl)-2-butamine (MBDB) was obtained within 13min of run. The method was validated presenting good linearity (r(2)>0.99), recovery ?90%, precision better than 12% RSD and acceptable accuracy in the range of 86-118% at three concentration levels (50, 100 and 500ng/mL). LODs and LOQs in the order of 1-5ng/mL and 5-10ng/mL, respectively, were obtained. After validation, the method was applied to eighty-seven vitreous humor samples and the results were compared to those obtained by a liquid chromatography tandem mass spectrometry (LC-MS/MS) screening method, routinely used by the forensic toxicology laboratory of the Sao Paulo State Police, Brazil. Cocaine was detected in 7.1%, cocaethylene in 3.6%, lidocaine in 2.4% and ketamine in 1.2% of the total number of analyzed samples. PMID:24325829

Costa, Jose Luiz; Morrone, Andre Ribeiro; Resende, Rodrigo Ribeiro; Chasin, Alice Aparecida da Matta; Tavares, Marina Franco Maggi

2014-01-15

353

A demonstration of the use of ultra-performance liquid chromatography-mass spectrometry [UPLC/MS] in the determination of amphetamine-type substances and ketamine for forensic and toxicological analysis.  

PubMed

We have recently seen the emergence of ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry as an alternative to traditional high-performance liquid chromatography techniques. The strengths of UPLC technology promote the ability to separate and identify drug compounds with significant gains in resolution and sensitivity and marked reductions in the overall time of analysis. As increased throughput is the desire of the practical toxicology laboratory, the aim of this study was to trial commercially available technology by assessment of the separation of several commonly encountered amphetamine-type substances. From injection of a poly-drug reference standard and whole blood extract, we successfully separated and identified amphetamine, methamphetamine, ephedrine, pseudoephedrine, phentermine, MDA, MDMA, MDEA and ketamine in less than 3 min using the Acquity UPLC-Micromass Quattro Micro API MS instrumentation (Waters Corporation, USA). In addition to this significant reduction in overall run time, all peaks exhibited acceptable resolution using selected ion recording (SIR), with analysis indicating the capability to separate 5-11 peaks in 1.75 min using the current system parameters. From this introductory data, it is therefore indicated that the technological advancements defining ultra-performance liquid chromatography will allow it to serve as a powerful analytical tool for rapid throughput analysis. PMID:16617037

Apollonio, Luigino G; Pianca, Dennis J; Whittall, Ian R; Maher, William A; Kyd, Jennelle M

2006-05-19

354

Stereoisomeric profiling of drugs of abuse and pharmaceuticals in wastewaters of Valencia (Spain).  

PubMed

The enantiomeric and diastereomeric profiling of chiral pharmaceuticals (ephedrine, norephedrine, atenolol and venlafaxine) and illicit drugs (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA) and 3,4-methylenedioxy-N-ethylamphetamine (MDEA)) was undertaken over a period of fourteen consecutive days in three wastewater treatment plants (WWTPs) in the city of Valencia, Spain. Degradation efficiency of WWTPs was found to be compound and enantiomer dependent. Selective enantiomer enrichment was observed for several target analytes. Amphetamine and MDMA were enriched with R(-)-enantiomers. 1S,2S(+)-pseudoephedrine was found to be more readily degradable during activated sludge treatment than its diastereomer 1R,2S(-)-ephedrine. Atenolol underwent enrichment with either S(-)- or R(+)-enantiomer in different WWTPs. This unexpected enantiomeric variation in the stereoselective degradation of atenolol could be attributed to different processes utilized during activated sludge treatment. The application of (enantiomeric) profiling of wastewater revealed usage patterns of chiral drugs in the Valencia region. PMID:25029504

Vazquez-Roig, Pablo; Kasprzyk-Hordern, Barbara; Blasco, Cristina; Picó, Yolanda

2014-10-01

355

Evaluation of amphetamine-type stimulant abuse through hair analysis: Results from 12 years of work.  

PubMed

Hair analysis is a reliable tool for detecting long-term exposure to illegal drugs, including amphetaminetype stimulants, over periods from a few weeks to a few months, depending on the length of the hair used for analysis. Between 2000 and 2012, over 600 hair samples were analysed at the Institute for Medical Research and Occupational Health, Croatia (IMROH) for the presence of amphetamine-type stimulants. IMROH has used the same procedure for testing hair samples for amphetamine-type stimulants for over twelve years. It was found to be reliable for confirming repeated abuse of amphetamine-type stimulants. Gas chromatography/mass spectrometry (GC/MS) was used to determine amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA-Ecstasy), and 3,4-methylenedioxyethylamphetamine (MDEA) in hair. Hair samples were either taken at the Institute, delivered by mail or a third person brought them to the laboratory. In most cases, the hair samples were tested anonymously. A total of 23 % of the tested samples were positive for one or more amphetamine-type stimulant. MDMA was the most frequently detected substance, whereas the most frequent combination was amphetamine with MDMA. Our results could indicate a trend in amphetamine-type stimulant abuse among young people in the Republic of Croatia. PMID:24945418

Br?i? Kara?onji, Irena; Brajenovi?, Nataša

2014-06-01

356

High throughput screening of CO2 solubility in aqueous monoamine solutions.  

PubMed

Post-combustion Carbon Capture and Storage technology (CCS) is viewed as an efficient solution to reduce CO(2) emissions of coal-fired power stations. In CCS, an aqueous amine solution is commonly used as a solvent to selectively capture CO(2) from the flue gas. However, this process generates additional costs, mostly from the reboiler heat duty required to release the carbon dioxide from the loaded solvent solution. In this work, we present thermodynamic results of CO(2) solubility in aqueous amine solutions from a 6-reactor High Throughput Screening (HTS) experimental device. This device is fully automated and designed to perform sequential injections of CO(2) within stirred-cell reactors containing the solvent solutions. The gas pressure within each reactor is monitored as a function of time, and the resulting transient pressure curves are transformed into CO(2) absorption isotherms. Solubility measurements are first performed on monoethanolamine, diethanolamine, and methyldiethanolamine aqueous solutions at T = 313.15 K. Experimental results are compared with existing data in the literature to validate the HTS device. In addition, a comprehensive thermodynamic model is used to represent CO(2) solubility variations in different classes of amine structures upon a wide range of thermodynamic conditions. This model is used to fit the experimental data and to calculate the cyclic capacity, which is a key parameter for CO(2) process design. Solubility measurements are then performed on a set of 50 monoamines and cyclic capacities are extracted using the thermodynamic model, to asses the potential of these molecules for CO(2) capture. PMID:21341690

Porcheron, Fabien; Gibert, Alexandre; Mougin, Pascal; Wender, Aurélie

2011-03-15

357

HPLC and MS/MS study of polar contaminants in a wetland adjoining a sour-gas plant  

SciTech Connect

An analytical methodology was developed for target analyses and broad spectrum characterization of polar contaminants such as nitrogenous and organosulfur compounds in wetlands using the complementary techniques of HPLC with electrochemical (EC) detection and tandem MS with probe and electrospray ionization. Tandem MS was well suited for the identification and quantification of mixtures of polar compounds in water samples and soil extracts, while HPLC-EC provided sensitive detection of compounds transparent to MS detection and conventional methods. The usefulness of the methodology is demonstrated by studying the removal of polar contaminants from a wetland in western Canada affected by releases of hydrocarbon-rich condensate and free product from an adjoining sour-gas plant. The concern is that the mobile water-soluble polar contaminants may not be as efficiently attenuated by volatilization or adsorption processes as the more hydrophobic hydrocarbons and that some of the polar toxic compounds may break through to contaminate groundwater and surface waters. Samples of groundwater, surface water, and aqueous soil extracts were analyzed to quantify levels of polar contaminants in the presence of high concentrations of hydrocarbons. The use of water extracts reduced the background interference from hydrocarbons and other non-polar compounds that were present in the soil samples. HPLC-EC was used to quantify the target compounds that included monoethanolamine, diethanolamine and methyldiethanolamine and sulfolane-derived compounds while tandem MS was used to identify related compounds and degradation products. Influent concentrations were in the ppm range and discharge concentrations were in the ppb range.

Dickson, L.C.; Headley, J.V.; Peru, K. [National Hydrology Research Inst., Saskatoon, Saskatchewan (Canada); Spiegel, K.; Gandrass, J. [GKSS Research Centre, Geesthacht (Germany)

1995-12-31

358

New antimonato polyoxovanadates based on the [V 14IVSb 8IIIO 42(H 2O)] 4- cluster type  

NASA Astrophysics Data System (ADS)

Two new antimonato polyoxovanadates with compositions (enH 2) 2[V 14Sb 8O 42(H 2O)]•3H 2O ( 1) (en = ethylenediamine) and (ppzH 2) 2[V 14Sb 8O 42(H 2O)] ( 2) (ppz = piperazine) were synthesized under solvothermal conditions. Compound 1 crystallizes in the monoclinic space group P2 1/n with a = 13.6969(8) Å, b = 11.9183(10) Å, c = 19.0413(12) Å, ? = 108.346(7), V = 2950.4(4) Å 3 and compound 2 crystallizes in the monoclinic space group P2 1/c with lattice parameters a = 13.7114(10) Å, b = 11.9476(5) Å, c = 19.9391(14) Å, ? = 109.043(8), V = 3087.6(3) Å 3. The central structural motif of both structures can be derived from the {V 18O 42} archetype cluster replacing four VO 5 square pyramids by four Sb 2O 5 moieties yielding two perpendicular oriented eight-membered rings composed of edge-sharing VO 5 polyhedra. According to bond valence sum calculations the electronic situation in the clusters may be formulated as [V IV14Sb III8O 42(H 2O)] 4-. In compound 1 the cluster anions are arranged along the b-axis in a …ABAB… fashion, whereas the anions in 2 are stacked along the c-axis in a …AAA… mode. In both compounds neighbored clusters exhibit relatively short Sb-O separations indicating weak inter-cluster interactions, leading to a layer-like arrangement of the [V IV14Sb III8O 42(H 2O)] 4- anions. In the structure of 1 the charge balancing organic ammonium ions are fully disordered whereas the organic cations in 2 are ordered. Further characterization of compound 1 and 2 revealed that the initially used N,N,N',N'-tetramethylethylenediamine was decomposed to ethylenediamine in 1 and the applied amine 1 -methylpiperazine was fragmented to piperazine in 2. Syntheses with the latter amine led to crystallization of compound 1. But compound 2 could not be prepared applying piperazine in the reaction slurry.

Antonova, Elena; Wutkowski, Adam; Näther, Christian; Bensch, Wolfgang

2011-12-01

359

Discovery of a novel CCR5 antagonist lead compound through fragment assembly.  

PubMed

CCR5, as the major co-receptor for HIV-1 entry, is an attractive novel target for the pharmaceutical industry in the HIV-1 therapeutic area. In this study, based on the structures of maraviroc and 1,4-bis(4-(7-chloroquinolin-4-yl)piperazin-1-yl)butane-1,4-dione (1), which was identified using structure-based virtual screening in conjunction with a calcium mobilization assay, a series of novel small molecule CCR5 antagonists have been designed and synthesized through fragment assembly. Preliminary SARs were obtained, which are in good agreement with the molecular binding model and should prove helpful for future antagonist design. The novel scaffold presented here might also be useful in the development of maraviroc-derived second generation CCR5 antagonists. PMID:18830165

Liu, Yanqing; Zhou, Enkun; Yu, Kunqian; Zhu, Jin; Zhang, Yu; Xie, Xin; Li, Jian; Jiang, Hualiang

2008-01-01

360

Synthesis and in vitro antimycobacterial activity of B-ring modified diaryl ether InhA inhibitors  

PubMed Central

In earlier work structure-based design studies resulted in the discovery of alkyl substituted diphenyl ether inhibitors of InhA, the enoyl reductase from Mycobacterium tuberculosis. Compounds such as 5-hexyl-2-phenoxyphenol 19 are nM inhibitors of InhA and inhibit the growth of both sensitive and isoniazid-resistant strains of Mycobacterium tuberculosis with MIC90 values of 1–2 µg/mL. However, despite their promising in vitro activity, these compounds have ClogP values of over 5. In efforts to reduce the lipophilicity of the compounds, and enhance potentially enhance compound bioavailability, a series of B ring analogues of 19 were synthesized that contained either heterocylic nitrogen rings or phenyl rings having amino, nitro, amide or piperazine functions. Compounds 3c, 3e and 14a show comparable MIC90 values to that of 19, but have improved ClogP values. PMID:18457948

am Ende, Christopher W.; Knudson, Susan E.; Liu, Nina; Childs, James; Sullivan, Todd J.; Boyne, Melissa; Xu, Hua; Gegina, Yelizaveta; Knudson, Dennis L.; Johnson, Francis; Peloquin, Charles A.; Slayden, Richard A.; Tonge, Peter J.

2008-01-01

361

Characterization of saturable absorbers using an open-aperture Gaussian-beam Z scan  

SciTech Connect

We present a theoretical investigation on the open-aperture Gaussian-beam Z-scan technique for two dominant saturable absorption models, by using the Adomian decomposition method. Analytic expressions of the Z-scan traces are deduced for a cw laser and a pulsed laser, respectively; in particular, for performable simulations, the optimal sum upper limit is found. We give an experimental demonstration, in which a side-chain azobenzene polymer poly [6-[1-(4-(4-nitrophenylazo)phenyl) piperazine] hexyl methacrylate] (Pda) film behaves as a test sample. The results manifest that our theory is reasonable and the Pda film is a good saturable absorber at the wavelength of 532 nm.

Gu Bing; Fan Yaxian; Wang Jin; Chen Jing; Ding Jianping; Wang Huitian; Guo Bin [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China) and School of Physical Science and Technology, Nanjing Normal University, Nanjing 210097 (China); National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); College of Information Science and Technology, Nanjing Forestry University, Nanjing 210037 (China)

2006-06-15

362

Adsorption, inhibition, and biotransformation of ciprofloxacin under aerobic conditions.  

PubMed

The adsorption, inhibition, and biotransformation of the fluoroquinolone antibiotic ciprofloxacin (CIP) under aerobic conditions were investigated in this study. The maximum adsorption capacity and the Langmuir constant were 37.9 mg CIP/g VSS and 37 L/g, respectively. A glucose-fed aerobic culture was inhibited by CIP at 10mg/L or higher and the degree of inhibition increased with increasing CIP concentration. However, the microbial activity recovered to some extent with prolonged incubation under a semi-continuous feeding mode. A low extent of CIP biotransformation was observed in an aerobic, glucose-fed culture derived from poultry litter extract. LC/UV/MS analysis of the biotransformation product showed that only the piperazine ring was oxidized, while the antibiotic quinolone part of CIP was intact. PMID:23902755

Liu, Zhanguang; Sun, Peizhe; Pavlostathis, Spyros G; Zhou, Xuefei; Zhang, Yalei

2013-09-01

363

Synthesis and antibacterial activity of quinolone-based compounds containing a coumarin moiety.  

PubMed

A new series of quinolone-based compounds containing a coumarin moiety have been synthesized and studied for their antibacterial activity against a panel of gram-positive and gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The results of the antibacterial evaluation of N-[2-(coumarin-3-yl)ethyl]piperazinyl quinolone derivatives in comparison with parent quinolones (norfloxacin, ciprofloxacin, and enoxacin) indicated that N-[2-(coumarin-3-yl)-2-oxoethyl]ciprofloxacin derivative (compound 8b) showed comparable or more potent antibacterial activity with respect to the reference drugs against the test strains. Generally, in both gram-positive and gram-negative bacteria, better results are obtained with cyclopropyl at the N-1 position of the quinolone ring and 2-oxo- on the ethyl spacer of coumarin and piperazine rings. PMID:18072241

Emami, Saeed; Foroumadi, Alireza; Faramarzi, Mohammad A; Samadi, Nasrin

2008-01-01

364

OA10 is a novel p38alpha mitogen-activated protein kinase inhibitor that suppresses osteoclast differentiation and bone resorption.  

PubMed

In search of anti-bone resorbing agents for the potential treatment of osteoporosis, we synthesized a novel compound Tert-butyl 4-(3-[1H-indole-2-carboxamido]benzoyl)piperazine-1-carboxylate (OA10) and found that OA10 is capable of inhibiting RANKL-mediated osteoclast formation and osteoclastic bone resorption in a dose-dependent manner. This biological effect is further supported by the fact that OA10 suppressed osteoclastic-specific gene expression, including tartrate-resistant acid phosphatase, cathepsin K receptor, and calcitonin receptor. Further molecular mechanism investigation revealed OA10 inhibited p38 phosphorylation, suppressed c-fos and NFATc1 expression without affecting NF-?B or JNK signaling pathways. Taken together, this study suggested that OA10 can inhibit osteoclastogenesis by suppressing p38-c-Fos-NFATc1 cascade. OA10 may be developed as a therapeutic drug for osteoclast-related osteolytic diseases. PMID:24357524

Jiang, T; Qin, A; Shao, Z Y; Tian, B; Zhai, Z J; Li, H W; Zhu, Z A; Dai, K R; Ming, H Zheng; Yu, Y P; Jiang, Q

2014-05-01

365

Synthesis of novel ciprofloxacin analogues and evaluation of their anti-proliferative effect on human cancer cell lines.  

PubMed

A series of twenty two novel 1-cyclopropyl-6-fluoro-4-oxo-7-(4-substituted piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid analogues have been synthesized, characterized ((1)H NMR, (13)C NMR and LCMS) and evaluated for their inhibitory activity on the proliferation of human caucasian acute lymphoblastic leukemia cells (CCRF-CEM), breast adenocarcinoma cells (MDA-MB-468) and human colon carcinoma cells (HCT-116). Among all the synthesized ciprofloxacin analogues 3t at 50 ?M showed comparable potency to doxorubicin (10 ?M) in all three cell lines and 3j inhibited proliferation of MDA-MB-468 up to 35% selectively over other two cell lines. PMID:24138941

Suresh, Narva; Nagesh, Hunsur Nagendra; Sekhar, Kondapalli Venkata Gowri; Kumar, Anil; Shirazi, Amir N; Parang, Keykavous

2013-12-01

366

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The baseline campaign with 30% MEA has given heat duties from 40 to 70 kcal/gmol CO{sub 2} as predicted by the stripper model. The Flexipak 1Y structured packing gives significantly better performance than IMTP 40 duped packing in the absorber, but in the stripper the performance of the two packings is indistinguishable. The FTIR analyzer measured MEA volatility in the absorber represented by an activity coefficient of 0.7. In the MEA campaign the material balance closed with an average error of 3.5% and the energy balance had an average error of 5.9.

Gary T. Rochelle; Marcus Hilliard; Eric Chen; Babatunde Oyenekan; Ross Dugas; John McLees

2005-07-31

367

CO2 Capture by Absorption with Potassium Carbonate  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. In Campaign 3 of the pilot plant, the overall mass transfer coefficient for the stripper with 7 m MEA decreased from 0.06 to 0.01 mol/(m{sup 3}.s.kPa) as the rich loading increased from 0.45 to 0.6 mol CO{sub 2}/mol MEA. Anion chromatography has demonstrated that nitrate and nitrite are major degradation products of MEA and PZ with pure oxygen. In measurements with the high temperature FTIR in 7 m MEA the MEA vapor pressure varied from 2 to 20 Pa at 35 to 70 C. In 2.5 m PZ the PZ vapor pressure varied from 0.2 to 1 Pa from 37 to 70 C.

Gary T. Rochelle; Marcus Hilliard; Eric Chen; Babatunde Oyenekan; Ross Dugas; John McLees; Andrew Sexton; Amorvadee Veawab

2005-01-26

368

Improved solvent formulations for efficient CO? absorption and low-temperature desorption.  

PubMed

This experimental study describes efficient CO? capture by 2-amino-2-methyl-1-propanol (AMP)/piperazine (PZ) in ethylene glycol monoethyl ether (EGMEE, 2-ethoxyethanol) containing approximately 15 wt?% of water. In these experiments, the solvent is continuously circulated between the absorber (packed-bed reactor at 30, 40, or 45?°C) and the desorber (at 80, 85, or 90?°C). The CO? -solvent reaction equilibria have been investigated by using ¹³C?NMR spectroscopy, which provides confirmatory evidence that the formation of mono- and biscarbamate derivatives of PZ accounts for most of the CO? absorbed by the AMP/PZ/EGMEE/H?O blend. The solid-state structures of AMP carbamate and of the carbonate salt of protonated AMP have been determined by using XRD. Both AMPCO?(-) and CO(3)(2-) species completely convert to the monoalkyl carbonates on dissolving the respective salts in methanol, ethanol, or ethylene glycol. PMID:22778091

Barzagli, Francesco; Di Vaira, Massimo; Mani, Fabrizio; Peruzzini, Maurizio

2012-09-01

369

Amphoteric, prevailingly cationic L-arginine polymers of poly(amidoamino acid) structure: synthesis, acid/base properties and preliminary cytocompatibility and cell-permeating characterizations.  

PubMed

A linear amphoteric poly(amidoamino acid), L-ARGO7, is prepared by Michael-type polyaddition of L-arginine with N,N'-methylenebisacrylamide. Chain-extension of acrylamide end-capped L-ARGO7 oligomers with piperazine leads to high-molecular-weight copolymers in which L-arginine maintains its absolute configuration. Acid/base properties of L-ARGO7 polymers show isolectric points of ? 10 and positive net average charges per repeating unit at pH = 7.4 from 0.25 to 0.40. These arginine-rich synthetic polymers possibly share some of the unique biological properties of polyarginine cell-permeating peptides. In vitro tests with mouse embryo fibroblasts balb/3T3 clone A31 show that L-ARGO7 polymers are endowed with effective cell internalization ability combined with minimal cytotoxicity. PMID:24821667

Ferruti, Paolo; Mauro, Nicolò; Falciola, Luigi; Pifferi, Valentina; Bartoli, Cristina; Gazzarri, Matteo; Chiellini, Federica; Ranucci, Elisabetta

2014-03-01

370

Design, synthesis, biological evaluation of substituted benzofurans as DNA gyraseB inhibitors of Mycobacterium tuberculosis.  

PubMed

DNA gyrase of Mycobacterium tuberculosis (MTB) is a type II topoisomerase and is a well-established and validated target for the development of novel therapeutics. By adapting the medium throughput screening approach, we present the discovery and optimization of ethyl 5-(piperazin-1-yl) benzofuran-2-carboxylate series of mycobacterial DNA gyraseB inhibitors, selected from Birla Institute of Technology and Science (BITS) database chemical library of about 3000 molecules. These compounds were tested for their biological activity; the compound 22 emerged as the most active potent lead with an IC50 of 3.2±0.15?M against Mycobacterium smegmatis DNA gyraseB enzyme and 0.81±0.24?M in MTB supercoiling activity. Subsequently, the binding of the most active compound to the DNA gyraseB enzyme and its thermal stability was further characterized using differential scanning fluorimetry method. PMID:25129171

Renuka, Janupally; Reddy, Kummetha Indrasena; Srihari, Konduri; Jeankumar, Variam Ullas; Shravan, Morla; Sridevi, Jonnalagadda Padma; Yogeeswari, Perumal; Babu, Kondra Sudhakar; Sriram, Dharmarajan

2014-09-01

371

Synthesis and antibacterial activity of nitroaryl thiadiazole-gatifloxacin hybrids.  

PubMed

A number of gatifloxacin analogues containing a nitroaryl-1,3,4-thiadiazole moiety attached to the piperazine ring at C-7 position were prepared and evaluated as antibacterial agents against a panel of gram-positive and gram-negative bacteria. Among synthesized compounds, nitrofuran analog 6a exhibited more potent inhibitory activity against gram-positive bacteria including Staphylococcus epidermidis (MIC=0.0078 microg/mL), Bacillus subtilis (MIC=0.0039 microg/mL), Enterococcus faecalis (MIC=0.125 microg/mL) and Micrococcus luteus (MIC=0.125 microg/mL), with respect to other synthesized compounds and reference drug gatifloxacin. The target compounds were also assessed for their cytotoxic activity against normal mouse fibroblast (NIH/3T3) cells using MTT assay. The results indicated that these compounds exhibit antibacterial activity at non-cytotoxic concentrations. PMID:18950903

Jazayeri, Seyyedehsamira; Moshafi, Mohammad Hassan; Firoozpour, Loghman; Emami, Saeed; Rajabalian, Saeed; Haddad, Mitra; Pahlavanzadeh, Farahnaz; Esnaashari, Manzarbanoo; Shafiee, Abbas; Foroumadi, Alireza

2009-03-01

372

Synthesis and antibacterial activity of some novel N-substituted piperazinyl-quinolones.  

PubMed

A series of N-substituted-piperazinyl-quinolones were synthesized and evaluated for in vitro antibacterial activity. Compounds with a 2-(2,4-dichlorophenyl)-2-oxoethyl group attached to the piperazine ring (5a-c) had similar antibacterial activity to the reference drugs, ciprofloxacin, norfloxacin and enoxacin against both Gram-positive and Gram-negative bacteria. The oximes 6a-c and 6g-i were almost less active than corresponding ketones against the tested microorganisms, however the 2,4-difluorophenyl analogues (6g-i) were more active than 2,4-dichlorophenyl derivatives (6a-c). If the hydrogen of oxime is replaced with a benzyl group (6d-f & 6j-l), in-vitro antibacterial activity was decreased against both Gram-positive and Gram-negative bacteria. Generally ciprofloxacin derivatives were more active than norfloxacin and enoxacin derivatives. PMID:11822230

Foroumadi, A; Davood, A; Mirzaei, M; Emami, S; Moshafi, M H

2001-01-01

373

Construction of two novel indium phosphites with (3,6)- and (3,5)-connected frameworks: Synthesis, structure and characterization  

NASA Astrophysics Data System (ADS)

Two novel anionic indium phosphites, formulated as [H3O][In(HPO3)2] (1) and [C4H12N2][In2(HPO3)3(C2O4)] (2), were prepared under hydrothermal conditions by using piperazine (PIP) as a structure-directing agent (SDA). Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 crystallize in the hexagonal space group P63mc (No. 186) and orthorhombic space group Cmcm (No. 63), respectively. Compound 1, constructed from InO6 octahedra and HPO3 pseudo-pyramids, exhibits a rare (3,6)-connected layer structure with kgd (Kagome dual) topology. Compound 2, on the other hand, features a 3D phosphite-oxalate hybrid structure with intersecting 8- and 12-MRs channels. From a topological perspective 2 can be regarded as a (3, 5)-connected binodal net with the Schläfli symbol (42.6)(42.65.83).

Li, Huiduan; Zhang, Lirong; Huo, Qisheng; Liu, Yunling

2013-01-01

374

Vortioxetine for the treatment of major depressive disorder.  

PubMed

Vortioxetine (Brintellix(®), 1-[2-(2,4-dimethylphenyl-sulfanyl)-phenyl]-piperazine) is a multimodal antidepressant targeting the 5-HT1A, 5-HT1B, 5-HT1D, 5-HT3, 5-HT7 receptors and the serotonin (5-HT) transporter (5-HTT). Vortioxetine administration induces antidepressant- and anxiolytic-like effects, and can enhance cognitive performance in rodents. Several clinical trials have reported the efficiency and a satisfactory tolerability of vortioxetine treatment in depressed patients. Remarkably, vortioxetine has a specific positive impact on cognitive symptoms in depressed patients. Overall, vortioxetine is an efficacious antidepressant drug for the treatment of patients with a major depressive episode and has a unique mechanism of action offering a new therapeutic option. PMID:25166025

Tritschler, Laurent; Felice, Daniela; Colle, Romain; Guilloux, Jean-Philippe; Corruble, Emmanuelle; Gardier, Alain Michel; David, Denis Joseph

2014-11-01

375

EVALUATION OF ANTHELMINTIC ACTIVITIES OF AERIAL PARTS of Celsia coromandeliane Vahl AND Mollugo pentaphylla Linn  

PubMed Central

The anthelmintic activities of different extracts of aerial parts of Celsia coromandeliane Vahl and Mollugo pentaphylla Linn were evaluated separately on adult Indian earthworm (Pheritima posthuma). It was found that petroleum ether (PECC), chloroform (CCC), ethanol (ECC) extract of C. coromandeliane and petroleum ether (PEMP), benzene (BMP), ethyl acetate (EAMP), ethanol (EMP) extract of M. pentaphylla showed anthelmintic activities at the concentration of 5 mg/ml of each. The anthelmintic effects of CCC, PEMP, BMP and EAMP at 5 mg/ml and PECC at 10-mg/ml concentrations are comparable with that of the effects produced by the reference standards albendazole (10 mg/ml) and piperazine citrate (10 mg/ml). PMID:22557204

Pal, Dilip Kumar; Majumder, Avijit; Bandyopadhyay, Pranab Kumar; Jena, Anima; Panday, Rajesh

2006-01-01

376

(C4N2H12)3[Ln3(OH)(SO4)7] (Ln = Sm, Eu, and Tb): a series of honeycomb-like open-framework lanthanide sulfates with extra-large channels containing 24-membered rings.  

PubMed

Three novel organic amine templated honeycomb-like lanthanide sulfates, (C4N2H12)3[Ln3(OH)(SO4)7] (Ln = Sm (1), Eu (2), and Tb (3)), with extra-large channels containing 24-membered rings (24MR) have been synthesized by using chair form piperazine as the structure-directing agent under one-pot solvothermal reactions. The three compounds are isostructural, and the open framework of the title compounds is the first lanthanide sulfate example with extra-large channels containing 24MR. It has an acs framework topology. The three compounds are strong luminescent materials that display characteristic Sm(3+), Eu(3+), and Tb(3+) emission bands in the visible region. The observed second-harmonic generation efficiencies of the three compounds are all 0.4 times that of urea. TGA profiles and XRD measurements demonstrate their high thermal stability. PMID:23464507

Zhang, Deng; Lu, Yun; Zhu, Dunru; Xu, Yan

2013-03-18

377

Investigation of the inhibiting action of O-, S- and N-dithiocarbamato(1,4,8,11-tetraazacyclotetradecane)cobalt(III) complexes on the corrosion of iron in HClO 4 acid  

NASA Astrophysics Data System (ADS)

The inhibiting properties of four macrocyclic cobalt(III) complexes of the general formula [Co III(Rdtc)cyclam](ClO 4) 2, where cyclam and Rdtc- refer to 1,4,8,11-tetraazacyclotetradecane and morpholine-, thiomorpholine-, piperazine-, N-methylpiperazine-dithiocarbamates, respectively, has been studied on the corrosion of iron in aerated 0.1 M HClO 4 solutions by potentiodynamic polarization (dc) technique and electrochemical impedance spectroscopy (ac). Inhibitor efficiency for the corrosion of iron is found to be better for cobalt complexes then for related amino-ligands. The impedance increases with inhibitor concentration. Polarization curves indicate that the inhibitors are predominantly mixed-type. Better protection by the complex inhibitors was obtained with longer immersion time. The best fit for inhibitors adsorption is obtained using the Langmuir isotherm model. Molecular modeling calculations were used to correlate structural properties of the complex species and their inhibition efficiency.

Babi?-Samardžija, K.; Khaled, K. F.; Hackerman, N.

2005-02-01

378

Synthesis and antinociception activity of new substituted phenothiazines and ethylenediamines as antihistaminic drugs.  

PubMed

Antihistamines play an important role in medicine when it comes to relieving seasonal or non-seasonal rhinitis, the common cold, and itching. They have also shown many various combinations of pharmacological properties such as anti-inflammatory and analgesic activities. Phenothiazines and ethylenediamines are 2 important classes of antihistamines with analgesic activities in addition to other pharmacological effects. In this study, some new derivatives of these compounds (V-IX) were synthesized and their antinociceptive behaviors were examined by pharmacological tests. The results indicated that new analogue with methyl groups produced a better analgesic activity than chlorine atoms but less than III (without any substitutions) in ethylenediamine class. Also in phenothiazine class, adding pyrimidine and pyridine substituted showed the better analgesic activity compared to other groups. Moreover, the analgesic activities proved that dimethylamine is the best group in amino alkyl side chain of these molecules relative to the substituted piperazines in new analogues. PMID:24446204

Ahmadi, A; Naderi, N; Souri, M; Shirkavand, F; Nahri-Niknafs, B

2014-11-01

379

Synthesis, crystal structures, and magnetic properties of cobalt(II) and nickel(II) complexes of 2,2?-bipyridine-6,6?-dicarboxylate: three three-dimensional networks formed via hydrogen bonding interactions  

Microsoft Academic Search

Three Co(II) and Ni(II) complexes, namely [Co(bpdc)(H2O)2] (1), [Ni(bpdc)(H2O)2] (2), and [Co2(bpdc)2(prz)0.5(H2O)3]·0.5H2O (3) (H2bpdc = 2,2?-bipyridine-6,6?-dicarboxylic acid and prz = piperazine), have been synthesized from H2bpdc and the corresponding metal salts under hydrothermal conditions. The complexes were characterized by physico-chemical\\u000a and spectroscopic methods, as well as by X-ray crystallography. Compounds 1 and 2 both consist of neutral mononuclear molecules, of [Co(bpdc)(H2O)2] and [Ni(bpdc)(H2O)2], respectively.

Jin-Zhong Gu; Dong-Yu Lv; Zhu-Qing Gao; Jian-Zhao Liu; Wei Dou

2011-01-01

380

Cinnarizinium 3,5-dinitro-salicylate  

PubMed Central

The title compound [systematic name: 4-diphenyl­methyl-1-(3-phenylprop-2-en-1-yl)-piperazin-1-ium 2-carb­oxy-4,6-dinitro­pheno­late], C26H29N2 +·C7H3N2O7 ?, is the dinitro­salicylate salt of a tertiary amine. Deprotonation of the carb­oxy­lic acid group occurred on the phenolic hy­droxy group. The diaza­cyclo­hexane ring adopts a chair conformation. Intra­molecular O—H?O and inter­molecular C—H?O and N—H?O hydrogen bonds are observed. The N—H?O hydrogen bonds are bifurcated at the H atom and connect the cinnarizinium and 3,5-dinitro­salicylate ions together. Inter­molecular C—H?O hydrogen bonds connect the components into layers perpendicular to the crystallographic a axis. PMID:22606110

Dayananda, Alaloor S.; Yathirajan, Hemmige S.; Gerber, Thomas; Hosten, Eric; Betz, Richard

2012-01-01

381

Pharmacokinetic-Pharmacodynamic Contributions to the Convulsant Activity of Fluoroquinolones in Rats  

PubMed Central

The in vivo convulsant activities in rats of five representative fluoroquinolones (FQs), norfloxacin, enoxacin, sparfloxacin, fleroxacin, and pefloxacin, were compared. The experimental approach allowed distinction between the drugs’ ability to reach the pharmacological receptors at the level of the central nervous system (pharmacokinetic contribution) and their ability to interact with these receptors (pharmacodynamic contribution). The presence of a methyl group on the piperazine moiety decreased the pharmacodynamic contribution to the convulsant activity by severalfold, and the ratios of concentrations of the FQs in cerebrospinal fluid (CSF) to concentrations of unbound FQs in plasma varied from about 5 to 75% as a function of lipophilicity. Interestingly, FQs with the highest intrinsic convulsant activities had the lowest levels of diffusion in CSF and vice versa. This in vivo approach provides information complementary to that of in vitro experiments and should be recommended for early preclinical assessment of a new FQ’s epileptogenic risk. PMID:10348785

Delon, Annie; Bouquet, Serge; Huguet, Francois; Brunet, Valerie; Courtois, Philippe; Couet, William

1999-01-01

382

The first bis-cyanoxime: synthesis and properties of a new versatile and accessible polydentate bifunctional building block for coordination and supramolecular chemistry.  

PubMed

A new multidentate bifunctional organic ligand – di-N,N?-(2-cyano-2-oximinoacetyl)piperazine – was synthesized in high yield using a two-step procedure carried out under ambient conditions. At first, the reaction of piperazine and neat methylcyanoacetate led to the di-N,N?-(cyanoacetyl)piperazine (1), which then was converted into bis-cyanoxime, di-N,N?-(2-cyano-2-oximinoacetyl)piperazine (HL, 2) using a room temperature nitrosation reaction with gaseous methylnitrite. Synthesized bis-cyanoxime was characterized by 1H, 13C NMR, UV-visible, IR spectroscopy and the X-ray analysis. The ligand 2 exists as a mixture of three diastereomers arising from the syn- and anti-geometry of the cyanoxime group. The prolonged crystallization of 2 from an ethanol–water mixture leads to the formation of: (a) colorless crystals that according to the X-ray analysis contain a 51.2:48.8% co-crystallized mixture of both isomers that have the same H-bonding motif (minority), and (b) a white amorphous material that represents an almost pure anti-isomer (majority). The deprotonation of 2 leads to the formation of a yellow dianion that demonstrated pronounced solvatochromism of its n ? ?* transition in the nitroso-chromophore. The disodium salt Na2L·4H2O (3) was obtained from 2 using NaOC2H5 in ethanol. The new bis-cyanoxime 2 reacts with Tl2CO3 and AgNO3 in aqueous solutions with the formation of light-stable, sparingly soluble yellow precipitates of M?2L·xH2O composition (M? = Tl, Ag; Tl = 4, x = 0; Ag = 5, x = 2). The reaction of 3 with Ni2+ or K2M??Cl4 (M?? = Pd, Pt) in aqueous solutions leads to NiL·4H2O (6), PdL·4H2O (7) and PtL·5H2O (8). The crystal structure of 4 was determined and revealed the formation of a 3D-coordination polymeric complex in which the bis-cyanoxime acts as a dianionic, bridging, formally decadentate ligand. Each Tl(I) center has two bonds (2.655, 2.769 Å), shorter than the sum of ionic radii Tl–O (oxime group), and three longer, >2.89 Å, mostly electrostatic Tl···O contacts, involving oxygen atoms of the amide-group and the oxime-group of neighboring units. Among several possible binding modes, the coordination of the bis-cyanoxime dianion of 2 adopted in complex 4 is unusual, and evidenced its great potential as a versatile building block for coordination and supramolecular chemistry. PMID:23385567

Cheadle, Carl; Gerasimchuk, Nikolay; Barnes, Charles L; Tyukhtenko, Sergiy I; Silchenko, Svitlana

2013-04-14

383

Quantum mechanics/molecular mechanics modeling of fatty acid amide hydrolase reactivation distinguishes substrate from irreversible covalent inhibitors  

PubMed Central

Carbamate and urea derivatives are important classes of fatty acid amide hydrolase (FAAH) inhibitors that carbamoylate the active-site nucleophile Ser241. In the present work, the reactivation mechanism of carbamoylated FAAH is investigated by means of a quantum mechanics/molecular mechanics (QM/MM) approach. The potential energy surfaces for decarbamoylation of FAAH covalent adducts, deriving from the O-aryl carbamate URB597 and from the N-piperazinylurea JNJ1661610, were calculated and compared to that for deacylation of FAAH acylated by the substrate oleamide. Calculations show that a carbamic group bound to Ser241 prevents efficient stabilization of transition states of hydrolysis, leading to large increments in the activation barrier. Moreover, the energy barrier for the piperazine carboxylate was significantly lower than that for the ciclohexyl carbamate derived from URB597. This is consistent with experimental data showing slowly reversible FAAH inhibition for the N-piperazinylurea inhibitor and irreversible inhibition for URB597. PMID:23425199

Lodola, Alessio; Capoferri, Luigi; Rivara, Silvia; Tarzia, Giorgio; Piomelli, Daniele; Mulholland, Adrian; Mor, Marco

2013-01-01

384

Site-specific rate constants for iron removal from diferric transferrin by nitrilotris(methylenephosphonic acid) and pyrophosphate.  

PubMed

The kinetics of iron removal from human serum diferric transferrin by nitrilotris(methylenephosphonic acid) (NTP) and pyrophosphate (PPi) have been studied in 0.1 M, pH 7.4, N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonate buffer at 25 degrees C using urea/polyacrylamide gel electrophoresis. The four microscopic rate constants required for a complete description of iron removal from the two transferrin metal-binding sites have been measured at 100 mM concentrations of NTP and PPi. There is very good agreement between the rate constants determined by electrophoresis in this study and the corresponding rate constants determined spectrophotometrically for monoferric transferrins that have been labeled at the empty binding site with substitutionally inert Co(III). The results validate the use of cobalt-labeled transferrins as models for kinetic studies on iron removal from diferric transferrin. PMID:2168158

Bali, P K; Harris, W R

1990-09-01

385

Antituberculosis: Synthesis and Antimycobacterial Activity of Novel Benzimidazole Derivatives  

PubMed Central

A total of seven novel benzimidazoles were synthesized by a 4-step reaction starting from 4-fluoro-3-nitrobenzoic acid under relatively mild reaction conditions. The synthesized compounds were screened for their antimycobacterial activity against M. tuberculosis H37Rv (MTB-H37Rv) and INH-resistant M. tuberculosis (INHR-MTB) strains using agar dilution method. Three of them displayed good activity with MIC of less than 0.2??M. Compound ethyl 1-(2-(4-(4-(ethoxycarbonyl)-2-aminophenyl)piperazin-1-yl)ethyl)-2-(4-(5-(4-fluorophenyl)pyridin-3-ylphenyl-1H-benzo[d]imidazole-5-carboxylate (5g) was found to be the most active with MIC of 0.112??M against MTB-H37Rv and 6.12??M against INHR-MTB, respectively. PMID:24381946

Keng Yoon, Yeong; Ashraf Ali, Mohamed; Choon, Tan Soo; Ismail, Rusli; Chee Wei, Ang; Suresh Kumar, Raju; Beevi, Farzana

2013-01-01

386

Effect of putative efflux pump inhibitors and inducers on the antimicrobial susceptibility of Campylobacter jejuni and Campylobacter coli.  

PubMed

The CmeABC efflux pump plays an important role in the antimicrobial resistance of Campylobacter jejuni and Campylobacter coli. The aim of this investigation was to study the effect of putative efflux pump inhibitors, phenyl-arginine-beta-naphthylamide (PAbetaN) and 1-(1-naphthylmethyl)-piperazine (NMP), as well as the effect of putative efflux pump inducers, sodium salicylate and sodium deoxycholate, on the MIC levels of erythromycin, ciprofloxacin, kanamycin, tetracycline and rifampicin for C. jejuni and C. coli. Our results indicated that susceptibility to erythromycin and rifampicin increased, respectively, 8- to 32- and 8- to 64-fold in the presence of PAbetaN and to a lesser extent in the presence of NMP. Salicylate produced a 2- to 4-fold increase in ciprofloxacin MIC values, whereas little effect was observed in the presence of deoxycholate. PMID:18566143

Hannula, Minna; Hänninen, Marja-Liisa

2008-07-01

387

Ab-Initio Study of Electronic Structure and Magnetic Properties of Pipz-H2[MnF4(HF2)  

NASA Astrophysics Data System (ADS)

The full-potential linearized augmented plane wave method was applied to study the electronic and the magnetic properties of the compound pipz-H2[MnF4(HF2)](pipz=piperazine). The band structure, the total density of states, the partial density of states and the electron density were calculated to explain the electronic and the magnetic properties of pipz-H2[MnF4(HF2)] in the ferromagnetic state. It is found that the magnetic moment of the molecule mainly comes from the Mn atoms with partial contribution from the F atoms. The symmetrical sigma/sigma bonds via H atoms along Mn-F-H-F-Mn chains and the weak direct-exchange interaction between F(2), F(3) and Mn atoms have effect on the electronic structure and the magnetism of pipz-H2[MnF4(HF2)].

Yao, Kai-Lun; Wang, Li-Qiang; Liu, Zu-Li; Zou, Wei-Dong; Luo, Shi-Jun; Zu, Feng-Xia; Zhu, Lin

2003-10-01

388

Mutagenicity of urine from mice exposed orally to nitrite and various aminated antiparasitic drugs  

SciTech Connect

Mutagenic N-nitroso compound formation from the in vitro reaction of amebicides and anthelmintic drugs, which are pyrimidine derivatives or contain secondary aliphatic amines or heterocyclic nitrogens, has been previously described. Under similar conditions, antiparasitic drugs containing halogenated derivatives of tertiary amines or quaternary ammonium salts do not form mutagenic nitrosated compounds. In the present study the mutagenic activity of mouse urine was determined after oral administration of sodium nitrite and the two above-mentioned groups of drugs. Results show that the simultaneous administration of piperazine or chloroquine with sodium nitrite produced urinary mutagens that appeared conjugated as glucuronides, whereas pyrantel pamoate and dehydroemetine in the presence of nitrite caused only slightly mutagenic urine. No mutagenic activity was detected in the urine of mice to which halogenated derivatives of tertiary amines (iodochlorhydroxyquin) or quaternary ammonium salts (bephenium hydroxynaphthoate) were administered together with nitrite.

Alba, M.A.; Aguirre, J.E.; Ramirez, J.; de Nava, C.C. (U.N.A.M. (Mexico))

1989-01-01

389

Regulatory role of adrenergic neurotransmitters on the spontaneous muscular activity in the ruminant trematode Paramphistomum cervi (Paramphistomatidae).  

PubMed

The neuromuscular system of helminths is an important area for target identification and drug development. Many anthelmintics, namely ivermectin, levamisole, piperazine, pyrantel, praziquantel and organophosphates, produce paralysis of helminths by affecting their neuromuscular systems. The neuromuscular system of helminths is also an important area of research to identify some of the important differences between the neuromuscular physiology of helminths and mammals. The identification of differences would help in developing newer target-specific, safe and effective anthelmintics. The present study was carried out to investigate the effects of different adrenergic neurotransmitters (epinephrine, norepinephrine, dopamine, l-dopa) and their antagonists (propranolol and haloperidol) on the spontaneous muscular activity of isometrically mounted Paramphistomum cervi. PMID:23721888

Saikia, B; Barua, C C; Hazarika, S; Lahon, L C; Saikia, D; Borah, R S; Verma, P K

2014-09-01

390

Synthesis, characterization, equilibrium study and biological activity of Cu(II), Ni(II) and Co(II) complexes of polydentate Schiff base ligand  

NASA Astrophysics Data System (ADS)

Schiff base ligand, 1,4-bis[(2-hydroxybenzaldehyde)propyl]piperazine (BHPP), and its Cu(II), Ni(II) and Co(II) metal complexes were synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance and spectral (IR and UV-vis) studies. The ground state of BHPP ligand was investigated using the BUILDER module of MOE. Metal complexes are formed in the 1:1 (M:L) ratio as found from the elemental analysis and found to have the general formula [ML]·nH2O, where M = Co(II), Ni(II) and Cu(II), L = BHPP. In all the studied complexes, the (BHPP) ligand behaves as a hexadentate divalent anion with coordination involving the two azomethine nitrogen's, the two nitrogen atoms of piperazine ring and the two deprotonated phenolic OH-groups. The magnetic and spectral data indicates octahedral geometry of metal(II) complexes. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. They were found to be more active against Gram-positive than Gram-negative bacteria. Protonation constants of (BHPP) ligand and stability constants of its Cu2+, Co2+ and Ni2+ complexes were determined by potentiometric titration method in 50% DMSO-water solution at ionic strength of 0.1 M sodium nitrate. It has been observed that the protonated Schiff base ligand (BHPP) have four protonation constants. The divalent metal ions Cu2+, Ni2+ and Co2+ form 1:1 complexes.

El-Sherif, Ahmed A.; Shehata, Mohamed R.; Shoukry, Mohamed M.; Barakat, Mohammad H.

2012-10-01

391

Molecular Mechanism of MBX2319 Inhibition of Escherichia coli AcrB Multidrug Efflux Pump and Comparison with Other Inhibitors.  

PubMed

Efflux pumps of the resistance nodulation division (RND) superfamily, such as AcrB, make a major contribution to multidrug resistance in Gram-negative bacteria. The development of inhibitors of the RND pumps would improve the efficacy of current and next-generation antibiotics. To date, however, only one inhibitor has been cocrystallized with AcrB. Thus, in silico structure-based analysis is essential for elucidating the interaction between other inhibitors and the efflux pumps. In this work, we used computer docking and molecular dynamics simulations to study the interaction between AcrB and the compound MBX2319, a novel pyranopyridine efflux pump inhibitor with potent activity against RND efflux pumps of Enterobacteriaceae species, as well as other known inhibitors (D13-9001, 1-[1-naphthylmethyl]-piperazine, and phenylalanylarginine-?-naphthylamide) and the binding of doxorubicin to the efflux-defective F610A variant of AcrB. We also analyzed the binding of a substrate, minocycline, for comparison. Our results show that MBX2319 binds very tightly to the lower part of the distal pocket in the B protomer of AcrB, strongly interacting with the phenylalanines lining the hydrophobic trap, where the hydrophobic portion of D13-9001 was found to bind by X-ray crystallography. Additionally, MBX2319 binds to AcrB in a manner that is similar to the way in which doxorubicin binds to the F610A variant of AcrB. In contrast, 1-(1-naphthylmethyl)-piperazine and phenylalanylarginine-?-naphthylamide appear to bind to somewhat different areas of the distal pocket in the B protomer of AcrB than does MBX2319. However, all inhibitors (except D13-9001) appear to distort the structure of the distal pocket, impairing the proper binding of substrates. PMID:25114133

Vargiu, Attilio V; Ruggerone, Paolo; Opperman, Timothy J; Nguyen, Son T; Nikaido, Hiroshi

2014-10-01

392

A 3D porous indium(III) coordination polymer involving in-situ ligand synthesis  

SciTech Connect

The hydrothermal reaction of In{sup 3+} and 1,2,4-benzenetricarboxylic acid with the presence of piperazine leads to the generation of a novel 3D porous coordination polymer, [H{sub 3}O][In{sub 2}(btc)(bdc)(OH){sub 2}].5.5H{sub 2}O (1), (btc=1,2,4-benzenetricarboxylate, bdc=1,4-benzenedicarboxylate). Compound 1 crystallizes in orthorhombic space group Pbca with a=16.216(7) A, b=13.437(6) A, c=31.277(14) A, and Z=8. It is interesting to find that the in-situ decarboxylation reaction of 1,2,4-benzenetricarboxylate (btc) partially transformed into 1,4-benzenedicarboxylate (bdc) occurs. The 16 indium(III) centers were linked by four btc, four bdc and two mu{sub 2}-OH ligands to form a box-girder. The adjacent box-girders are further connected by the bdc and btc ligands to generate a novel porous metal-organic framework containing nanotubular open channel with a cross-section of approximately 11.5x11.3 A{sup 2}. The micropores are occupied by lattice water molecules, and the solvent-accessible volume of the unit cell was estimated to be 3658.6 A{sup 3}, which is approximately 53.7% of the unit-cell volume (6815.4 A{sup 3}). - Graphical Abstract: The hydrothermal reaction of In{sup 3+} and 1,2,4-benzenetricarboxylic acid with the presence of piperazine leads to the generation of a novel 3D porous coordination polymer, [H{sub 3}O][In{sub 2}(btc)(bdc)(OH){sub 2}].5.5H{sub 2}O, (btc=1,2,4-benzenetricarboxylate, bdc=1,4-benzenedicarboxylate).

Han Zhengbo, E-mail: ceshzb@lnu.edu.c [College of Chemistry, Liaoning University, Shenyang 110036 (China); Song Yongjuan; Ji Jianwei; Zhang Wei; Han Guangxi [College of Chemistry, Liaoning University, Shenyang 110036 (China)

2009-11-15

393

Theoretical and experimental studies of the isomeric protonation in solution for a prototype aliphatic ring containing two nitrogens  

PubMed Central

Theoretical calculations were carried out for studying the tautomeric protonation of N-methyl piperazine as a prototype six-member aliphatic ring containing a secondary and a tertiary nitrogen atom. The protonation was investigated in three solvents: water, acetonitrile, and dichloromethane. Calculations were performed up to the B3LYP/aug-cc-pvtz and QCISD(T)/CBS levels by applying the IEF-PCM polarizable continuum dielectric solvent model. Relative solvation free energies also were calculated upon explicit solvent models by utilizing the free-energy perturbation theory as implemented in Monte Carlo simulations. The relative free energy for the N-methyl piperazine tautomer protonated at the secondary (NMps) rather than at the tertiary (NMpt) nitrogen was calculated at a ratio of 47/53 in infinitely dilute aqueous solution. The ratio further decreases in lower polarity solvents. In contrast, NMR experiments suggest that the protonation takes place primarily at the secondary nitrogen in 0.37 molar aqueous solution with NMps/NMpt = 80/20. The NMps tautomer is exclusive in dichloromethane at the same concentration. The discrepancy between theory and experiment was resolved by considering association equilibria in parallel with the protonation for the solute. As a result, the theoretically predicted tautomer ratios were obtained in close agreement with the experimental values. The NMps tautomer could form a preferable dimeric structure, where one or two chloride anion(s) is/are in hydrogen bonds with protons of the associating monomers. The calculations suggest that the proton relocation may take place by solvent assistance in water or along an intramolecular proton jump in the twist-boat conformation. The predicted activation free energy was about 10 kcal/mol on the basis of variable temperature NMR experiments in DCM. PMID:19994881

Maheshwari, Aditya; Kim, Yong-Wah

2009-01-01

394

Design and evaluation of a solid sampler for the monitoring of airborne 1,6-hexamethylene diisocyanate (HDI) and its prepolymers in two-component spray painting.  

PubMed

An active, solvent-free solid sampler was developed for the collection of 1,6-hexamethylene diisocyanate (HDI) aerosol and prepolymers. The sampler was made of a filter impregnated with 1-(2-methoxyphenyl)piperazine contained in a filter holder. Interferences with HDI were observed when a set of cellulose acetate filters and a polystyrene filter holder were used; a glass fiber filter and polypropylene filter cassette gave better results. The applicability of the sampling and analytical procedure was validated with a test chamber, constructed for the dynamic generation of HDI aerosol and prepolymers in commercial two-component spray paints (Desmodur N75) used in car refinishing. The particle size distribution, temporal stability, and spatial uniformity of the simulated aerosol were established in order to test the sampler. The monitoring of aerosol concentrations was conducted with the solid sampler paired to the reference impinger technique (impinger flasks contained 10 mL of 0.5 mg/mL 1-(2-methoxyphenyl)piperazine in toluene) under a controlled atmosphere in the test chamber. Analyses of derivatized HDI and prepolymers were carried out by using high-performance liquid chromatography and ultraviolet detection. The correlation between the solvent-free and the impinger techniques appeared fairly good (Y = 0.979X-0.161; R = 0.978), when the tests were conducted in the range of 0.1 to 10 times the threshold limit value (TLV) for HDI monomer and up to 60 micrograms/m3 (3 U.K. TLVs) for total -N=C=O groups. PMID:1642167

Huynh, C K; Vu-Duc, T; Savolainen, H

1992-03-01

395

DAT/SERT Selectivity of Flexible GBR 12909 Analogs Modeled Using 3D-QSAR Methods  

PubMed Central

The dopamine reuptake inhibitor GBR 12909 (1-{2-[bis(4-fluorophenyl)methoxy]ethyl}-4-(3-phenylpropyl)piperazine, 1) and its analogs have been developed as tools to test the hypothesis that selective dopamine transporter (DAT) inhibitors will be useful therapeutics for cocaine addiction. This 3D-QSAR study focuses on the effect of substitutions in the phenylpropyl region of 1. CoMFA and CoMSIA techniques were used to determine a predictive and stable model for the DAT/serotonin transporter (SERT) selectivity (represented by pKi (DAT/SERT)) of a set of flexible analogs of 1, most of which have eight rotatable bonds. In the absence of a rigid analog to use as a 3D-QSAR template, six conformational families of analogs were constructed from six pairs of piperazine and piperidine template conformers identified by hierarchical clustering as representative molecular conformations. Three models stable to y-value scrambling were identified after a comprehensive CoMFA and CoMSIA survey with Region Focusing. Test set correlation validation led to an acceptable model, with q2 = 0.508, standard error of prediction = 0.601, two components, r2 = 0.685, standard error of estimate = 0.481, F value = 39, percent steric contribution = 65, and percent electrostatic contribution = 35. A CoMFA contour map identified areas of the molecule that affect pKi (DAT/SERT). This work outlines a protocol for deriving a stable and predictive model of the biological activity of a set of very flexible molecules. PMID:17127069

Gilbert, Kathleen M.; Boos, Terrence L.; Dersch, Christina M.; Greiner, Elisabeth; Jacobson, Arthur E.; Lewis, David; Matecka, Dorota; Prisinzano, Thomas E.; Zhang, Ying; Rothman, Richard B.; Rice, Kenner C.; Venanzi, Carol A.

2007-01-01

396

Synthesis, characterization, equilibrium study and biological activity of Cu(II), Ni(II) and Co(II) complexes of polydentate Schiff base ligand.  

PubMed

Schiff base ligand, 1,4-bis[(2-hydroxybenzaldehyde)propyl]piperazine (BHPP), and its Cu(II), Ni(II) and Co(II) metal complexes were synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance and spectral (IR and UV-vis) studies. The ground state of BHPP ligand was investigated using the BUILDER module of MOE. Metal complexes are formed in the 1:1 (M:L) ratio as found from the elemental analysis and found to have the general formula [ML]·nH(2)O, where M=Co(II), Ni(II) and Cu(II), L=BHPP. In all the studied complexes, the (BHPP) ligand behaves as a hexadentate divalent anion with coordination involving the two azomethine nitrogen's, the two nitrogen atoms of piperazine ring and the two deprotonated phenolic OH-groups. The magnetic and spectral data indicates octahedral geometry of metal(II) complexes. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. They were found to be more active against Gram-positive than Gram-negative bacteria. Protonation constants of (BHPP) ligand and stability constants of its Cu(2+), Co(2+) and Ni(2+) complexes were determined by potentiometric titration method in 50% DMSO-water solution at ionic strength of 0.1 M sodium nitrate. It has been observed that the protonated Schiff base ligand (BHPP) have four protonation constants. The divalent metal ions Cu(2+), Ni(2+) and Co(2+) form 1:1 complexes. PMID:22935596

El-Sherif, Ahmed A; Shehata, Mohamed R; Shoukry, Mohamed M; Barakat, Mohammad H

2012-10-01

397

Assessment of synergistic combination potential of probiotic and bacteriophage against antibiotic-resistant Staphylococcus aureus exposed to simulated intestinal conditions.  

PubMed

This study was designed to evaluate the combined effect of probiotic Lactobacillus rhamnosus and bacteriophage SA11 on the control of antibiotic-sensitive Staphylococcus aureus (ASSA) and antibiotic-resistant S. aureus (ARSA) under the simulated intestinal conditions. The survivability of ASSA and ARSA were determined in the simulated phosphate-buffered saline (PBS)-, trypticase soy broth (TSB)-, and milk-based gastric juices adjusted to pH 2.0, 3.0, and 5.0 at 37 °C for 30 min. The inhibitory effect of bacteriophage SA11 and probiotic on the growth of ASSA and ARSA was evaluated in the simulated intestinal juices at 37 °C for 20 h. The least reductions in the numbers of ASSA and ARSA were observed in the milk-based gastric juices at pH 2.0 (<1 log). No significant changes in the teichoic acid-mediated sliding motility were observed for ASSA and ARSA after 30-min exposure to the simulated gastric juices (pH 2.0, 3.0, and 5.0), responsible for the enhanced bacterial attachment to the epithelial cells. The bacteriophage SA11 was stable down to pH 5.0 and up to 0.06 % bile salts. The bacteriophage SA11 combined with probiotic effectively inhibited the growth of ASSA and ARSA in the simulated intestinal conditions, showing more than 4 log reduction. The relative expression levels of adhesion-related genes (clfA, eno, and fnbA) and efflux-related genes (mdeA, norB, and norC) were less decreased in ARSA than in ASSA after exposure to the simulated gastrointestinal conditions. These results might shed light on the application of bacteriophage to control the ingested antibiotic-resistant foodborne pathogens in the intestinal tract. PMID:25015717

Woo, Jihoon; Ahn, Juhee

2014-10-01

398

On-line liquid chromatography/tandem mass spectrometry simultaneous determination of opiates, cocainics and amphetamines in dried blood spots.  

PubMed

A novel approach has been developed for the illicit drugs quantitative determination using dried blood spots (DBS) on filter paper. The illicit drugs tested were opiates (morphine and its 3- and 6-glucuronide metabolites, codeine, 6-monoacetylmorphine), cocainics (ecgonine methylester, benzoylecgonine, cocaine, cocaethylene) and amphetamines (amphetamine, methamphetamine, MDA, MDMA, MDEA). The described method, requiring a small blood volume, is based on high performance liquid chromatography coupled to tandem mass spectrometry using on-line extraction. A Whatman card 903 was spotted with 30?L of whole blood and left overnight to dry at room temperature. A 3-mm diameter disk was removed using a manual punch, suspended in 150?L of water for 10min with ultrasonication, and then 100?L was injected in the on-line LC-MS/MS system. An Oasis HLB was used as an extraction column and a C18 Atlantis as an analytical column. The chromatographic cycle was performed with 20mM ammonium formate buffer (pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 16min. Detection was performed in positive electrospray ionization mode (ESI+) with a Quattro Micro (Waters). Recoveries of all analytes were up to 80%. DBS were stored in duplicate at 4°C and -20°C for up to 6 months. Illicit drugs seemed to be much more stabled at -20°C. Furthermore, it was tested whether analysis of DBS may be as reliable as that of whole blood investigating authentic samples; significant correlations were obtained. This DBS assay has potential as rapid, sensitive and inexpensive option for the illicit drugs determination in small blood volumes, which seems of great interest in suspected cases of driving under the influence of drugs. PMID:22281234

Saussereau, E; Lacroix, C; Gaulier, J M; Goulle, J P

2012-02-15

399

Three serotonin responses in cultured mouse hippocampal and striatal neurons.  

PubMed

Serotonin (5-HT) produced 3 different types of responses in neurons of mouse hippocampal and striatal cell cultures. These 3 responses have been characterized in terms of their pharmacological specificity, physiological mechanism, and dependence on cytoplasmic components. The most frequently observed response was inhibitory and was the result of a receptor-mediated activation of an inwardly rectifying potassium conductance. Typically, the response peaked within 1-3 sec of agonist application and did not exhibit desensitization. 5-Methoxy-N,N-dimethyltryptamine also produced this response in both striatal and hippocampal cultures and had no effect on the other 5-HT currents observed in this study. The selective 5-HT agonists--8-hydroxy-2-(di-n-propylamino)-tetralin, 1-(m-chlorophenyl) piperazine, and 1-(2-methoxyphenyl) piperazine--did not activate this outward current response. Methysergide did not block the 5-HT-activated outward current and often acted as an agonist. The response was lost in low-series-resistance recordings which facilitate solution exchange between the patch electrode and the cell. The loss of this response was prevented by using high-resistance patch electrodes, which retard this exchange. The 2 other responses described in this study were excitatory. They were seen less often than the inhibitory response. One of the excitatory responses was fast, with a time to peak of approximately 200 msec and a duration of 2-4 sec. The other was slow, with a time to peak of 7-10 sec and a duration of approximately 30-40 sec. Both of these responses were accompanied by a conductance increase. The fast excitatory response reversed at depolarized potentials and desensitized with a rate that varied with voltage. Metoclopramide and d-tubocurarine completely and reversibly blocked this fast excitatory response, while methysergide had no effect. The fast excitatory response was not lost during intracellular dialysis of cells in cultures from either striatum or hippocampus. In cultures from both brain regions, the slow excitatory response was blocked by methysergide. The slow excitatory response was lost even in patch-clamp recordings with high-resistance electrodes. This response was similar to responses to dopamine, norepinephrine, and forskolin, all of which are known to activate adenylate cyclase in the CNS. PMID:2965756

Yakel, J L; Trussell, L O; Jackson, M B

1988-04-01

400

Gas pre-treatment and their impact on liquefaction processes  

SciTech Connect

Natural gas generally requires removal of H{sub 2}S, CO{sub 2}, COS, organic sulfur compounds, mercury and water prior to liquefaction in order to meet product specifications, avoid blockages and to prevent damage to process equipment. The cost of pre-treatment is dependent on the type and concentrations of the contaminants in the natural gas. Most of the operational base load LNG plants process feed gas with only low concentrations of CO{sub 2}, mercury and water as contaminants. This type of gas requires the minimum of treating, often comprising of a CO{sub 2} removal unit, molecular sieves for drying and a carbon bed for mercury removal. The Shell sulfinol process is the most widely applied acid gas removal process, serving some 40% of the installed base load LNG capacity, and has proven to be very reliable and cost effective. If substantial quantities of H{sub 2}S are present in the feed, a sulfur recovery unit is required as well. When mercaptans are also present in gas feed, the Shell Sulfinol process is strongly preferred, Almost the automatic choice for as the acid gas removal step, since it combines total CO{sub 2} and H{sub 2}S removal with mercaptan removal up to 97%. Formulated methyl diethanol amine (MDEA) solvents have a comparable capital cost to Sulfinol, but lack the mercaptan removal capabilities. There is one exception, the Flexsorb formulation (from Exxon) which also contains sulfolane. Later revamp of a gas pre-treatment unit from limited mercaptan handling capability to significant mercaptan handling capability can also elegantly be done using an integrated Sulfinol based concept. Whereas the capital cost for dehydration and mercury removal depend mainly on the natural gas throughput, the relative capital investment for acid gas removal treating in a LNG plant increases significantly with increasing CO{sub 2} content., At 2% mol CO{sub 2} the acid gas unit represents from 6% of the processing equipment cost at 2% mol CO{sub 2} but at 14% mol CO{sub 2} it represents 15% of the processing equipment cost. The capital cost for dehydration and mercury removal depend mainly on the natural gas throughput. New developments such as membrane technologies are starting to be considered as an option for bulk removal of CO{sub 2} but solvent absorption remains the only cost effective treatment process for gas to meet LNG specifications. Further developments may change this in the future.

Klinkenbijl, J.M.; Dillion, M.L.; Heyman, E.C.

1999-07-01

401

Identification of a lead small-molecule inhibitor of the Aurora kinases using a structure-assisted, fragment-based approach.  

PubMed

Aurora A and Aurora B are potential targets for anticancer drug development due to their roles in tumorigenesis and disease progression. To identify small-molecule inhibitors of the Aurora kinases, we undertook a structure-based design approach that used three-dimensional structural models of the Aurora A kinase and molecular docking simulations of chemical entities. Based on these computational methods, a new generation of inhibitors derived from quinazoline and pyrimidine-based tricyclic scaffolds were synthesized and evaluated for Aurora A kinase inhibitory activity, which led to the identification of 4-(6,7-dimethoxy-9H-1,3,9-triaza-fluoren-4-yl)-piperazine-1-carbothioic acid [4-(pyrimidin-2-ylsulfamoyl)-phenyl]-amide. The lead compound showed selectivity for the Aurora kinases when it was evaluated against a panel of diverse kinases. Additionally, the compound was evaluated in cell-based assays, showing a dose-dependent decrease in phospho-histone H3 levels and an arrest of the cell cycle in the G(2)-M fraction. Although biological effects were observed only at relatively high concentrations, this chemical series provides an excellent starting point for drug optimization and further development. PMID:16891462

Warner, Steven L; Bashyam, Sridevi; Vankayalapati, Hariprasad; Bearss, David J; Han, Haiyong; Mahadevan, Daruka; Von Hoff, Daniel D; Hurley, Laurence H

2006-07-01

402

Biochemical constituents of a wild strain of Schizophyllum commune isolated from Achanakmar-Amarkantak Biosphere Reserve (ABR), India.  

PubMed

A wild strain of Schizophyllum commune (MTCC 9670) isolated from Achanakmar-Amarkantak Biosphere Reserve of Central India was evaluated for the production of bioactive compounds. The chemical constituents of wild and in vitro grown cultures were compared. Under optimized conditions, different organic and aqueous extracts from mycelia and fruiting bodies were used to extract chemical components from the cultures grown in vitro. The gas chromatography combined wih mass spectrometry analysis of extracts identified two phenolic compounds, namely Phenyl benzoate (C13H10O2) and 4-(phenyl methoxy) phenol (C13H12O2) in the ethanolic extract of in vitro grown fruiting bodies and one antibacterial compound Pyrrolo (1, 2-a) piperazine-3, 6-dione (C7H10O2N2) in the methanolic extract of mycelia. High-performance liquid chromatography analysis revealed that the gallic acid and L-ascorbic acid were identifiable antioxidant components in the extracts possessing high free radical scavenging activity. The findings suggest that the wild strain of S. commune may serve as the source of novel bioactive compounds with effective antimicrobial and antioxidant activities. PMID:23475305

Tripathi, Arpita Mani; Tiwary, Bhupendra N

2013-08-01

403

Enrofloxacin hydro­chloride dihydrate  

PubMed Central

The asymmetric unit of the title compound, C19H23FN3O3 +·Cl?·2H2O [systematic name: 4-(3-carb­oxy-1-cyclo­propyl-6-fluoro-4-oxo-1,4-di­hydro­quin­o­lin-7-yl)-1-ethyl­piperazin-1-ium chloride dihydrate], consists of two independent monocations of the protonated enrofloxacin, two chloride anions and four water mol­ecules. In the cations, the piperazinium rings adopt chair conformations and the dihedral angles between the cyclo­propyl ring and the 10-membered quinoline ring system are 56.55?(2) and 51.11?(2)°. An intra­molecular O—H?O hydrogen bond is observed in each cation. In the crystal, the components are connected via O—H?Cl, N—H?Cl and O—H?O hydrogen bonds, and a ?–? inter­action between the benzene rings [centroid–centroid distance = 3.6726?(13)?Å], resulting in a three-dimensional array. PMID:24826167

Miranda-Calderón, Jorge E.; Gutiérrez, Lilia; Flores-Alamo, Marcos; García-Gutiérrez, Ponciano; Sumano, Héctor

2014-01-01

404

Pore with gate: modulating hydrogen storage in metal-organic framework materials via cation exchange.  

PubMed

A range of anionic metal-organic framework (MOF) materials has been prepared by combination of In(III) with tetracarboxylate isophthalate-based ligands. These materials incorporate organic cations, either H2ppz2+ (ppz = piperazine) or Me2NH2+, that are hydrogen bonded to the pore wall. These cations act as a gate controlling entry of N2 and H2 gas into and out of the porous host. Thus, hysteretic adsorption/desorption for N2 and H2 is observed in these systems, reflecting the role of the bulky hydrogen bonded organic cations in controlling the kinetic trapping of substrates. Post-synthetic cation exchange with Li+ leads to removal of the organic cation and the formation of the corresponding Li+ salts. Replacement of the organic cation with smaller Li+ leads to an increase in internal surface area and pore volume of the framework material, and in some cases to an increase in the isosteric heat of adsorption of H2 at zero coverage, as predicted by theoretical modelling. The structures, characterisation and analysis of these charged porous materials as storage portals for H2 are discussed. Inelastic neutron scattering experiments confirm interaction of H2 with the carboxylate groups of the isophthalate ligands bound to In(III) centres. PMID:22455060

Yang, Sihai; Callear, Samantha K; Ramirez-Cuesta, Anibal J; David, William I F; Sun, Junliang; Blake, Alexander J; Champness, Neil R; Schröder, Martin

2011-01-01

405

Optimization of Imidazo[4,5-b]pyridine-Based Kinase Inhibitors: Identification of a Dual FLT3/Aurora Kinase Inhibitor as an Orally Bioavailable Preclinical Development Candidate for the Treatment of Acute Myeloid Leukemia  

PubMed Central

Optimization of the imidazo[4,5-b]pyridine-based series of Aurora kinase inhibitors led to the identification of 6-chloro-7-(4-(4-chlorobenzyl)piperazin-1-yl)-2-(1,3-dimethyl-1H-pyrazol-4-yl)-3H-imidazo[4,5-b]pyridine (27e), a potent inhibitor of Aurora kinases (Aurora-A Kd = 7.5 nM, Aurora-B Kd = 48 nM), FLT3 kinase (Kd = 6.2 nM), and FLT3 mutants including FLT3-ITD (Kd = 38 nM) and FLT3(D835Y) (Kd = 14 nM). FLT3-ITD causes constitutive FLT3 kinase activation and is detected in 20–35% of adults and 15% of children with acute myeloid leukemia (AML), conferring a poor prognosis in both age groups. In an in vivo setting, 27e strongly inhibited the growth of a FLT3-ITD-positive AML human tumor xenograft (MV4–11) following oral administration, with in vivo biomarker modulation and plasma free drug exposures consistent with dual FLT3 and Aurora kinase inhibition. Compound 27e, an orally bioavailable dual FLT3 and Aurora kinase inhibitor, was selected as a preclinical development candidate for the treatment of human malignancies, in particular AML, in adults and children. PMID:23043539

2012-01-01

406

Microorganisms hydrolyse amide bonds; knowledge enabling read-across of biodegradability of fatty acid amides.  

PubMed

To get insight in the biodegradation and potential read-across of fatty acid amides, N-[3-(dimethylamino)propyl] cocoamide and N-(1-ethylpiperazine) tall oil amide were used as model compounds. Two bacteria, Pseudomonas aeruginosa PK1 and Pseudomonas putida PK2 were isolated with N-[3-(dimethylamino)propyl] cocoamide and its hydrolysis product N,N-dimethyl-1,3-propanediamine, respectively. In mixed culture, both strains accomplished complete mineralization of N-[3-(dimethylamino)propyl] cocoamide. Aeromonas hydrophila PK3 was enriched with N-(1-ethylpiperazine) tall oil amide and subsequently isolated using agar plates containing dodecanoate. N-(2-Aminoethyl)piperazine, the hydrolysis product of N-(1-ethylpiperazine) tall oil amide, was not degraded. The aerobic biodegradation pathway for primary and secondary fatty acid amides of P. aeruginosa and A. hydrophila involved initial hydrolysis of the amide bond producing ammonium, or amines, where the fatty acids formed were immediately metabolized. Complete mineralization of secondary fatty acid amides depended on the biodegradability of the released amine. Tertiary fatty acid amides were not transformed by P. aeruginosa or A. hydrophila. These strains were able to utilize all tested primary and secondary fatty acid amides independent of the amine structure and fatty acid. Read-across of previous reported ready biodegradability results of primary and secondary fatty acid amides is justified based on the broad substrate specificity and the initial hydrolytic attack of the two isolates PK1 and PK3. PMID:24509885

Geerts, Roy; Kuijer, Patrick; van Ginkel, Cornelis G; Plugge, Caroline M

2014-07-01

407

Oxidation of ofloxacin by Oxone/Co(2+): identification of reaction products and pathways.  

PubMed

Oxidative degradation of ofloxacin (OFX) by sulfate free radicals (SO4 (-•)) in the UV/Oxone/Co(2+)oxidation process was investigated for the first time, with a special focus upon identifying the transformation products as well as understanding the reaction pathways. Thirteen main compounds were identified after the initial transformation of OFX; the detailed structural information of which were characterized by high-performance liquid chromatography-high resolution mass spectrometry and MS fragmentation analysis. The degradation pathways mainly encompassed ring openings at both the piperazinyl substituent and the quinolone moiety, indicating that the usage of SO4 (-•) aided the oxidative degradation of OFX to undergo more facile routes compared to those in previous reports by using OH(•)/h(+) as the oxidant, where the initial transformation attacks were mainly confined to the piperazine moiety. Moreover, in this study, smart control over the pH conditions of the oxidation system via different modes of Oxone dosage resulted in the selective degradation of the functional sites of OFX molecule, where it was shown that the SO4 (-•)-driven destruction of the quinolone moiety of OFX molecule favored the neutral pH conditions. This would be beneficial for the reduction of bacterial resistance against quinolones in the aqueous environment. PMID:24174312

Pi, Yunqing; Feng, Jinglan; Sun, Jingyu; Song, Mengke; Sun, Jianhui

2014-02-01

408

In vitro cytotoxicity and phototoxicity of N-piperazinyl quinolone derivatives with a 2-thienyl group.  

PubMed

We examined the cytotoxic potential of nine N-[2-substituted-2-(2-thienyl)ethyl] piperazinyl quinolone derivatives on human oral epithelial mouth carcinoma (KB) and human squamous carcinoma (A431) cell lines. Phototoxic properties of these compounds were also evaluated by mouse 3T3 fibroblast under ultraviolet-A (UVA) irradiation. The percent of cell viability was evaluated by MTT assay. Compound 6 having a 4-[2-(phenylmethoxyimino)-2-(2-thienyl)ethyl] group attached to N4 position of piperazine ring of enoxacin showed the highest cytotoxicity potential on both A431 and KB cell lines (IC50 of 3.11+/-0.52 and 4.91+/-1.94 microg/ml, respectively). While some of the other tested compounds exhibited clear phototoxic potential in 3T3 cell line, compound 6 showed only a minor potential of phototoxicity. These findings suggest the high potential of 4-[2-(phenylmethoxyimino)-2-(2-thienyl)ethyl] derivative of enoxacin as a cytotoxic compound with low potency of phototoxic reactions. The mentioned chemical was identified to be of special interest for further characterization. PMID:17507195

Pardakhty, Abbas; Foroumadi, Alireza; Hashemi, Mehdi; Rajabalian, Saeed; Heidari, Mahmoud Reza

2007-09-01

409

Formation of secondary triplet species after excitation of fluoroquinolones in the presence of relatively strong bases.  

PubMed

Laser flash photolysis of 7-(piperazin-1-yl) fluoroquinolones leads to the formation of a triplet excited state (3A*) at the end of the pulse (lambdamax 520, 610, and 620 nm for enoxacin, ciprofloxacin, and norfloxacin, respectively). Phosphate and bicarbonate buffers react with 3A* to form a secondary triplet (3B*, reaction rates (0.8-9.9) x 108 M-1 s-1), whose T-T absorption is red-shifted (lambdamax 670 nm for enoxacin, 700 nm for ciprofloxacin and norfloxacin). The formation of a secondary triplet is not a common process and disagrees with previous work suggesting that electron transfer occurs between phosphate buffer and the primary triplet excited state with the formation of the anion radical of the fluoroquinolone (FQ.-). We have shown that the FQ.- transient absorption spectrum is quite distinct from that of 3B*. The photophysical characteristics of 3B* have been determined by energy transfer to naproxen, and it has been found that its energy is lower than that of 3A*. PMID:18717558

Lorenzo, Fernando; Navaratnam, Suppiah; Allen, Norman S

2008-09-17

410

Dopamine transport sites selectively labeled by a novel photoaffinity probe: 125I-DEEP  

SciTech Connect

The dopamine transporter was labeled using a photosensitive compound related to GBR-12909, {sup 125}I-1-(2-(diphenylmethoxy)ethyl)-4-(2- (4-azido-3-iodophenyl)ethyl)piperazine ({sup 125}I-DEEP). {sup 125}I-DEEP bound reversibly and with high affinity to the dopamine transport protein in the absence of light and could be covalently attached to the protein following exposure to UV light. In rat striatal homogenates, {sup 125}I-DEEP was found to incorporate covalently into a protein with apparent molecular weight of 58,000 Da. The properties of this binding protein were characteristic of the dopamine transporter since covalent attachment could be inhibited by dopamine-uptake blockers with the proper pharmacological rank order of potencies. Covalent binding was also inhibited in a stereospecific manner by (+) and (-) cocaine, as well as other cocaine analogs. The protein was not found in the cerebellum. The dopamine transporter appears to exist in a glycosylated form since photoaffinity-labeled transport sites could adsorb to wheat germ-agglutinin and could be specifically eluted from the column by beta-N-acetylglucosamine.

Grigoriadis, D.E.; Wilson, A.A.; Lew, R.; Sharkey, J.S.; Kuhar, M.J. (National Institute on Drug Abuse, Baltimore, MD (USA))

1989-08-01

411

Antiarrhythmic, hypotensive and ?1-adrenolytic properties of new 2-methoxyphenylpiperazine derivatives of xanthone.  

PubMed

The main goal of this study was to assess antiarrhythmic and hypotensive activity of new 2-methoxyphenylpiperazine derivatives of xanthone. In order to better understand mechanism of action of studied compounds, their abilities to antagonize the increase in blood pressure elicited by adrenaline, noradrenaline and methoxamine, as well as the antagonistic properties for ?1-adrenoceptors on isolated rat aorta were evaluated. Therapeutic antiarrhythmic activity was investigated in an adrenaline-induced model of arrhythmia. Hypotensive activity in normotensive rats was evaluated after oral administration. Influence on blood vasopressor response and ?1-adrenoceptors in rat thoracic aorta was evaluated to determine if the observed cardiovascular effects could be related to ?1-adrenolytic properties. Tested compounds produced antiarrhythmic and hypotensive activity. The most active compound was MH-99 - (R,S)-4-(2-hydroxy-3-(4-(2-methoxyphenyl)piperazine-1-yl)propoxy)-9H-xanthen-9-one hydrochloride. All studied compounds showed ?1-adrenolytic properties in the in vivo and in vitro tests. The results indicate that the new valuable compounds with antiarrhythmic and hypotensive activity might be found in the group of xanthone derivatives. Further pharmacological utility of these compounds should be investigated. PMID:24751714

Rapacz, Anna; Pytka, Karolina; Sapa, Jacek; Kubacka, Monika; Filipek, Barbara; Szkaradek, Natalia; Marona, Henryk

2014-07-15

412

Structure-activity relationship studies on isoindoline inhibitors of dipeptidyl peptidases 8 and 9 (DPP8, DPP9): is DPP8-selectivity an attainable goal?  

PubMed

This work represents the first directed study to identify modification points in the topology of a representative DPP8/9-inhibitor, capable of rendering selectivity for DPP8 over DPP9. The availability of a DPP8-selective compound would be highly instrumental for studying and untwining the biological roles of DPP8 and DPP9 and for the disambiguation of biological effects of nonselective DPP-inhibitors that have mainly been ascribed to blocking of DPPIV's action. The cell-permeable DPP8/9-inhibitor 7 was selected as a lead and dissected into several substructures that were modified separately for evaluating their potential to contribute to selectivity. The obtained results, together with earlier work from our group, clearly narrow down the most probable DPP8-selectivity imparting modification points in DPP8/9 inhibitors to parts of space that are topologically equivalent to the piperazine ring system in 7. This information can be considered of high value for future design of compounds with maximal DPP8 selectivity. PMID:21711053

Van Goethem, Sebastiaan; Matheeussen, Veerle; Joossens, Jurgen; Lambeir, Anne-Marie; Chen, Xin; De Meester, Ingrid; Haemers, Achiel; Augustyns, Koen; Van der Veken, Pieter

2011-08-25

413

Pharmacodynamic modeling of sequence-dependent antitumor activity of insulin-like growth factor blockade and gemcitabine.  

PubMed

Agents that block insulin-like growth factor (IGF) signaling are under investigation in clinical trials. Antitumor effects are likely to be enhanced when combined with other agents, but administration sequence effects on activity are not well-described. Three breast cancer cell lines (MCF-7, MDA-MB-231, and Hs-578T) were treated with Gemcitabine and small molecule receptor tyrosine kinase inhibitor cis-3-[3-(4-methyl-piperazin-l-yl)-cyclobutyl]1-(2-phenyl-quinolin-7-yl)-imidazo [1,5-a]pyrazin-8-ylamine (PQIP) as single agents and then in combination in the forward (Gemcitabine followed by PQIP) and reverse (PQIP followed by Gemcitabine) sequences. Antitumor effects were assessed longitudinally by Bayesian analysis using WinBUGS. The pharmacodynamic model adequately predicted the observed data. The differences in the cell-kill rate constants for the forward vs. reverse sequence ranged from 0.11 to 0.64 (day(-1)), and statistical significance was generally dependent on cell line and PQIP concentration. These data indicate that treatment with Gemcitabine first, followed by PQIP is superior to the reverse sequence in vitro. PMID:22101930

Khatri, Amit; Brundage, Richard C; Hull, Jessica M; Williams, Brent W; Yee, Douglas; Kirstein, Mark N

2012-03-01

414

Plaque Assay of Rickettsiae in a Mammalian Cell Line  

PubMed Central

Clear-cut and repeatable plaque assays were obtained for three rickettsiae of the spotted fever group (Rickettsia rickettsi, R. conori, and R. montana) in Vero cells used in a manner similar to that for arboviruses. In addition, three typhus group agents (R. typhi, R. canada, R. prowazeki) induced plaques in these cells. In preliminary tests Coxiella burneti (Nine Mile strain) failed to produce plaques. Comparable results were obtained in plastic flasks and plastic culture trays incubated in ambient air with or without addition of N-2-hydroxyethyl-piperazine-N?-2-ethanesulfinic acid buffer. Larger and more well defined R. rickettsi plaques were produced when cultures were overlaid with Leibovitz (L15) medium than with either medium 199 or Eagle medium. Phosphate-buffered saline containing bovine plasma albumin (fraction V), in contrast to brain heart infusion broth, as a diluent for preparing inocula consistently permitted development of larger and more numerous plaques with three agents: R. rickettsi, R. conori, and R. montana. When R. rickettsi and R. typhi were assayed in parallel in primary chicken embryo cultures and Vero cells, comparable results were obtained, but with R. canada results in Vero cells were superior. In contrast, R. prowazeki produced inconsistent results in Vero cells. Images PMID:4208640

Cory, J.; Yunker, C. E.; Ormsbee, R. A.; Peacock, M.; Meibos, H.; Tallent, G.

1974-01-01

415

Expression and Characterization of Acidothermus celluloyticus E1 Endoglucanase in Transgenic Duckweed Lemna minor 8627  

SciTech Connect

Endoglucanase E1 from Acidothermus cellulolyticus was expressed cytosolically under control of the cauliflower mosaic virus 35S promoter in transgenic duckweed, Lemna minor 8627 without any obvious observable phenotypic effects on morphology or rate of growth. The recombinant enzyme co-migrated with the purified catalytic domain fraction of the native E1 protein on western blot analysis, revealing that the cellulose-binding domain was cleaved near or in the linker region. The duckweed-expressed enzyme was biologically active and the expression level was up to 0.24% of total soluble protein. The endoglucanase activity with carboxymethylcellulose averaged 0.2 units mg protein{sup -1} extracted from fresh duckweed. The optimal temperature and pH for E1 enzyme activity were about 80 C and pH 5, respectively. While extraction with HEPES (N-[2-hydroxyethyl]piperazine-N{prime}-[2-ethanesulfonic acid]) buffer (pH 8) resulted in the highest recovery of total soluble proteins and E1 enzyme, extraction with citrate buffer (pH 4.8) at 65 C enriched relative amounts of E1 enzyme in the extract. This study demonstrates that duckweed may offer new options for the expression of cellulolytic enzymes in transgenic plants.

Sun, Y.; Cheng, J. J.; Himmel, M. E.; Skory, C. D.; Adney, W. S.; Thomas, S. R.; Tisserat, B.; Nishimura, Y.; Yamamoto, Y. T.

2007-01-01

416

Serotonin-stimulated phosphoinositide turnover: mediation by the S2 binding site in rat cerebral cortex but not in subcortical regions  

SciTech Connect

In rat cerebral cortex, serotonin (5-HT) stimulates phosphoinositide turnover with an EC50 of 1 microM in the presence of pargyline. The EC50 is 16-fold higher in the absence of pargyline. Selective S2 antagonists inhibit 5-HT-stimulated phosphoinositide turnover. Schild analysis of the blockade by ketanserin of the 5-HT effect gives an estimated Kd of ketanserin for the phosphoinositide-linked receptor of 11.7 nM, which agrees with the Kd (3.5 nM) of (/sup 3/H)ketanserin for the S2 site. Furthermore, MK-212, 5-HT and 5-fluorotryptamine stimulate phosphoinositide turnover with potencies that resemble their potencies at the S2 but not the S1 binding site. Of 11 agonists tested, the tryptamine derivatives tend to be more efficacious than the piperazine derivatives. The selective S1 agonist 8-hydroxy-2-(di-N-propylamino)tetralin is inactive at stimulating phosphoinositide turnover. No significant relationship exists between the regional distributions of 5-HT-stimulated phosphoinositide turnover and S2 binding sites. Furthermore, the S2 antagonist ketanserin is less potent and less efficacious in hippocampus and limbic forebrain than in cerebral cortex. These data suggest that 5-HT-stimulated phosphoinositide turnover is linked to the S2 binding site in rat cerebral cortex. However, 5-HT increases phosphoinositide turnover in subcortical regions by mechanisms other than stimulation of the S2 receptor.

Conn, P.J.; Sanders-Bush, E.

1985-07-01

417

Multifunctional Antioxidants for the Treatment of Age-Related Diseases  

PubMed Central

Analogs of N,N-dimethyl-4-(pyrimidin-2-yl)- piperazine-1-sulfonamide possessing either a free radical scavenger group (FRS), chelating groups (CHL), or both (FRS+CHL) have been synthesized. Electrospray ionization mass spectrometry studies indicate that select members of this series bind ions in the relative order of Cu1+= Cu2+ > Fe2+= Fe3+>Zn2+ with no binding of Ca2+ or Mg2+ observed. In vitro evaluation of these compounds in human lens epithelial, human retinal pigmented epithelial, and human hippocampal astrocyte cell lines indicates that all analogs possessing the FRS group as well as the water soluble vitamin E analog 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid protect these cells against decreased cell viability and glutathione levels induced by hydrogen peroxide. In addition, those compounds possessing CHL groups also protected these cells against hydroxyl radicals generated by the Fenton reaction. These compounds are good candidates for the preventive treatment of cataract, age-related macular degeneration (AMD), and Alzheimer's dementia (AD). PMID:20078105

Jin, Hongxia; Randazzo, James; Zhang, Peng; Kador, Peter F.

2010-01-01

418

Syntheses, structures, and photoluminescence of d 10 coordination architectures: From 1D to 3D complexes based on mixed ligands  

NASA Astrophysics Data System (ADS)

Six new compounds, namely, {[Cd 3(Himpy) 3(tda) 2]·3H 2O} n ( 1), {[Zn 3(bipy) 2(tda) 2(H 2O) 2]·4H 2O} n ( 2), {[Cd 3(bipy) 3(tda) 2]·4H 2O} n ( 3), {[Cd 3(tda) 2(H 2O) 3Cl]·H 2O} n ( 4), {[Zn 2(tz)(tda)(H 2O) 2]·H 2O} n ( 5) and {[Cd 7(pz)(tda) 4(OAc)(H 2O) 7]·3H 2O} n ( 6) [H 3tda = 1H-1,2,3-triazole-4,5-dicarboxylic acid, Himpy = 2-(1H-imidazol-2-yl)pyridine, bipy = 2,2'-bipyridine, Htz = 1H-1,2,4-triazole, H 2pz = piperazine] have been prepared under hydrothermal condition and characterized by elemental analyses, infrared spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction analyses. Compound 1 is a 1D column-like structure and displays a 3D supramolecular network via the ?···? stacking interaction. The compounds 2 and 3 exhibit similar 2D layer-like structure, which further extend to 3D supermolecular structure by the ?···? stacking interaction. All of compounds 4- 6 display 3D framework with diverse topology constructed from the tda 3- ligands in different coordination modes and secondary ligands (or bridging atom) connecting metal ions. Furthermore, the thermal stabilities and photoluminescent properties of compounds 1- 6 were studied.

Yuan, Gang; Shao, Kui-Zhan; Du, Dong-Ying; Wang, Xin-Long; Su, Zhong-Min

2011-05-01

419

Small-Molecule Inhibition and Activation-Loop Trans-Phosphorylation of the IGF1 Receptor  

SciTech Connect

The insulin-like growth factor-1 receptor (IGF1R) is a receptor tyrosine kinase (RTK) that has a critical role in mitogenic signalling during embryogenesis and an antiapoptotic role in the survival and progression of many human tumours. Here, we present the crystal structure of the tyrosine kinase domain of IGF1R (IGF1RK), in its unphosphorylated state, in complex with a novel compound, cis-3-[3-(4-methyl-piperazin-l-yl)-cyclobutyl]-1-(2-phenyl-quinolin-7-yl)-imidazo[1, 5-a]pyrazin-8-ylamine (PQIP), which we show is a potent inhibitor of both the unphosphorylated (basal) and phosphorylated (activated) states of the kinase. PQIP interacts with residues in the ATP-binding pocket and in the activation loop, which confers specificity for IGF1RK and the highly related insulin receptor (IR) kinase. In this crystal structure, the IGF1RK active site is occupied by Tyr1135 from the activation loop of an symmetry (two-fold)-related molecule. This dimeric arrangement affords, for the first time, a visualization of the initial trans-phosphorylation event in the activation loop of an RTK, and provides a molecular rationale for a naturally occurring mutation in the activation loop of the IR that causes type II diabetes mellitus.

Wu,J.; Li, W.; Craddock, B.; Foreman, K.; Mulvihill, M.; Ji, Q.; Miller, W.; Hubbard, S.

2008-01-01

420

Antituberculosis agents. VI. Activity of a new ciprofloxacin derivative against Mycobacterium avium and some drug-resistant strains of Mycobacterium tuberculosis.  

PubMed

The in vitro antimycobacterial activity of a new quinolone derivative, 1a containing 2-(2-furyl)-2-oxoethyl group at N-4 position of piperazine ring of Ciprofloxacin was tested for efficacy in vitro in TB-infected macrophage model (EC90 = 3.25 micrograms/ml and EC99 > 12.5 micrograms/ml). The MIC values of 1a were determined against M. tuberculosis strains resistant to Isoniazid (MIC = 1.56 micrograms/ml), Rifampin (MIC = 1.56 micrograms/ml), Ethambutol (MIC = 0.78 microgram/ml), Kanamycin (MIC = 0.78 microgram/ml) and Ciprofloxacin (MIC > 25 micrograms/ml). Furthermore, the MIC and selectivity index (SI) of 1a were evaluated against M. avium. Also, in this study the minimum bactericidal concentration (MBC) of 1a was determined against M. tuberculosis H37Rv (MBC = 6.25 micrograms/ml) and strain resistant to Rifampim (MBC = 25 micrograms/ml) and Isoniazid (MBC = 25 micrograms/ml). PMID:12481384

Foroumadi, A; Soltani, F; Moshafi, M H

2002-01-01

421

Complexation of N4-Tetradentate Ligands with Nd(III) and Am(III)  

SciTech Connect

To improve understanding of aza-complexants in trivalent actinide–lanthanide separations, a series of tetradentate N-donor ligands have been synthesized and their complexation of americium(III) and neodymium(III) investigated by UV–visible spectrophotometry in methanolic solutions. The six pyridine/alkyl amine/imine ligands are N,N0-bis(2-methylpyridyl)-1,2-diaminoethane, N,N0-bis(2-methylpyridyl)-1,3-diaminopropane, trans-N,N-bis(2-pyridylmethyl)-1,2-diaminocyclohexane (BPMDAC), N,N’-bis(2-pyridylmethyl)piperazine, N,N’-bis-[pyridin-2-ylmethylene]ethane-1,2-diamine, and trans-N,Nbis-([pyridin-2-ylmethylene]-cyclohexane-1,2-diamine. Each ligand has two pyridine groups and two aliphatic amine/imine N-donor atoms arranged with different degrees of preorganization and structural backbone rigidity. Conditional stability constants for the complexes of Am(III) and Nd(III) by these ligands establish the selectivity patterns. The overall selectivity of Am(III) over Nd(III) is similar to that reported for the terdentate bis(dialkyltriazinyl)pyridine molecules. The cyclohexane amine derivative (BPMDAC) is the strongest complexant and shows the highest selectivity for Am(III) over Nd(III) while the imines appear to prefer a bridging arrangement between two cations. These results suggest that this series of ligands could be employed to develop an enhanced actinide(III)– lanthanide(III) separation system.

Ogden, Mark D.; Sinkov, Sergey I.; Meier, G. Patrick; Lumetta, Gregg J.; Nash, Kenneth L.

2012-12-06

422

Fabrication and application of a new modified electrochemical sensor using nano-silica and a newly synthesized Schiff base for simultaneous determination of Cd2+, Cu2+ and Hg2+ ions in water and some foodstuff samples.  

PubMed

A new chemically modified carbon paste electrode was constructed and used for rapid, simple, accurate, selective and highly sensitive simultaneous determination of cadmium, copper and mercury using square wave anodic stripping voltammetry (SWASV). The carbon paste electrode was modified by N,N'-bis(3-(2-thenylidenimino)propyl)piperazine coated silica nanoparticles. Compared with carbon paste electrode, the stripping peak currents had a significant increase at the modified electrode. Under the optimized conditions (deposition potential, -1.100 V vs. Ag/AgCl; deposition time, 60s; resting time, 10s; SW frequency, 25 Hz; pulse amplitude, 0.15 V; dc voltage step height, 4.4 mV), the detection limit was 0.3, 0.1 and 0.05 ng mL(-1) for the determination of Cd(2+), Cu(2+) and Hg(2+), respectively. The complexation reaction of the ligand with several metal cations in methanol was studied and the stability constants of the complexes were obtained. The effects of different cations and anions on the simultaneous determination of metal ions were studied and it was found that the electrode is highly selective for the simultaneous determination of Cd(2+), Cu(2+) and Hg(2+). Furthermore, the present method was applied to the determination of Cd(2+), Cu(2+) and Hg(2+) in water and some foodstuff samples. PMID:23522108

Afkhami, Abbas; Soltani-Felehgari, Farzaneh; Madrakian, Tayyebeh; Ghaedi, Hamed; Rezaeivala, Majid

2013-04-10

423

Do imipramine and dihydroergosine possess two components - one stimulating 5-HT sub 1 and the other inhibiting 5-HT sub 2 receptors  

SciTech Connect

The mechanisms by which imipramine and dihydroergosine stimulate the 5-HT syndrome in rats and inhibit the head-twitch response in rats and mice were studied. Imipramine- and dihydroergosine-included stimulation of the 5-HT syndrome was inhibited stereoselectively by propranolol, a high affinity ligand for 5-HT{sub 1} receptor sites, but not by ritanserin, a specific 5-HT{sub 2} receptor antagonist. (-) -Propranolol potentiated the inhibitory effect of imipramine, but not of dihydroergosine on the head-twitch response, while ritanserin was without effect. As expected, 8-OH-DPAT, a selective 5-HT{sub 1A} receptor agonist, stimulated, and 5-HT{sub 1B} agonists CGS 12066B and 1-(trifluoromethylphenyl) piperazine (TFMPP) failed to stimulate the 5-HT syndrome induced in rats by pargyline and 5-HTP administration. A higher dose of ritanserin inhibited the syndrome. While 8-OH-DPAT alone produced all behavioral components of the 5-HT syndrome, dihydroergosine or imipramine alone even at very high doses never produced tremor or a more intensive forepaw padding as seen when these drugs were given in combination with pargyline and 5-HTP. A single administration of (-)-propranolol also inhibited the head-twitch response. This effect lasted in mice longer that after ritanserin administration. In in vitro experiments dihydroergosine expressed approximately twenty-fold higher affinity for {sup 3}H-ketanserin binding sites than imipramine.

Pericic, D.; Mueck-Seler, D. (Rudjer Boskovic Institute, Zagreb (Yugoslavia))

1990-01-01

424

Chiral and achiral imidazole-linked tetrahedral zinc phosphonate frameworks with photoluminescent properties.  

PubMed

Presented here are three imidazole-linked tetrahedral zinc phosphonate frameworks based on a special ligand 2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonic acid (= ImhedpH4) with both an organic imidazole linker and inorganic phosphonate groups. Three new compounds, namely, [Zn2(ImhedpH2)2(ox)](H2ppz) (1), Zn3(ImhedpH)2(H2O)4 (2) and [Zn3(Imhedp)2](H2ppz) (3) (ox = oxalate and ppz = piperazine), were obtained by hydrothermal synthesis and structurally characterized by single-crystal X-ray diffraction. Compound 1 shows a chain structure with the ox ligands linking the [Zn2(ImhedpH2)2] units, and the resulting chains are further connected to form a 3D structure through the strong N-H···O and O-H···O hydrogen bonds between the neighboring chains. Compound 2 displays an inorganic layer structure with dangling imidazole units, where these protonated imidazoles also act as pillars between adjacent inorganic layers. Compound 3 features an unusual chiral three-dimensional (3D) Zn-Imhedp framework with guest H2ppz(2+) cations. It can be topologically represented as a 4-connected qtz network. Furthermore, the luminescent properties of the three compounds were investigated in the solid state. PMID:24100382

Zhang, Xiu-Ling; Cheng, Kai; Wang, Fei; Zhang, Jian

2014-01-01

425

Synthesis, structure and characterization of two new open-framework gallium phosphite-oxalates of varying dimensionality  

NASA Astrophysics Data System (ADS)

Using N, N-dimethyl-piperazine as structure directing agent, two new gallium phosphite-oxalates [Ga2(HPO3)2(H2PO3)2(C2O4)](C6N2H16) (I) and [Ga2(HPO3)2(H2PO3)(C2O4)](C6N2H16)0.5 (II) have been synthesized under solvothermal and hydrothermal conditions, respectively and further characterized by powder X-ray diffraction, IR spectroscopy, TGA, ICP-AES and elemental analyses. Single crystal X-ray diffraction reveals that the striking feature of I and II is that they possess the same second building unit (SBU) Ga2P2 constructed from two GaO6 octahedra and two [HPO32-] pseudo-pyramids sharing oxygen atoms. However, due to the different connecting fashions of SBUs, [C2O42-] groups and [H2PO3-] pseudo-pyramids, the final frameworks of them are distinctly different. Compound I shows 2D layered structures with 8-membered ring (8-MR) windows in the ab plane while compound II presents a 3D open-framework with 8-MR channels along the b axis.

Li, Caixia; Huang, Liangliang; Zhou, Mingdong; Xia, Jing; Ma, Hongwei; Zang, Shuliang; Wang, Li

2013-12-01

426

Improved antifouling properties of polyamide nanofiltration membranes by reducing the density of surface carboxyl groups.  

PubMed

Carboxyls are inherent functional groups of thin-film composite polyamide nanofiltration (NF) membranes, which may play a role in membrane performance and fouling. Their surface presence is attributed to incomplete reaction of acyl chloride monomers during the membrane active layer synthesis by interfacial polymerization. In order to unravel the effect of carboxyl group density on organic fouling, NF membranes were fabricated by reacting piperazine (PIP) with either isophthaloyl chloride (IPC) or the more commonly used trimesoyl chloride (TMC). Fouling experiments were conducted with alginate as a model hydrophilic organic foulant in a solution, simulating the composition of municipal secondary effluent. Improved antifouling properties were observed for the IPC membrane, which exhibited lower flux decline (40%) and significantly greater fouling reversibility or cleaning efficiency (74%) than the TMC membrane (51% flux decline and 40% cleaning efficiency). Surface characterization revealed that there was a substantial difference in the density of surface carboxyl groups between the IPC and TMC membranes, while other surface properties were comparable. The role of carboxyl groups was elucidated by measurements of foulant-surface intermolecular forces by atomic force microscopy, which showed lower adhesion forces and rupture distances for the IPC membrane compared to TMC membranes in the presence of calcium ions in solution. Our results demonstrated that a decrease in surface carboxyl group density of polyamide membranes fabricated with IPC monomers can prevent calcium bridging with alginate and, thus, improve membrane antifouling properties. PMID:23205860

Mo, Yinghui; Tiraferri, Alberto; Yip, Ngai Yin; Adout, Atar; Huang, Xia; Elimelech, Menachem

2012-12-18

427

The cardioprotective effect of TG-6, a newly synthesized compound, on ischemia-reperfusion injury in rats.  

PubMed

We tested 3-nitro-4-((4-(2,3,4-trimethoxybenzyl)piperazin-1-yl)methyl) benzoylguanidine tartrate (TG-6) which is combinated of two known cardioprotective agents cariporide and trimetazidine, whether additively to reduce ischemia-reperfusion injury in rats. Using models of in vitro perfusion (Langendorff system) and in vivo open chest left anterior descending coronary artery ligation causing ischemia-reperfusion injury. We also used Fura-2 to measure the cytosolic Ca²? concentrations ([Ca²?]i) in cardiomyocytes, western blot analysis the protein expression of Kv1.4, Kv4.2, Kv4.3 in myocardial ischemia-reperfusion rats. TG-6 improved the cardiac function in both in vivo and in vitro models, lowered Lactate Dehydrogenase (LDH), Creatine Kinase (CK), Malodialdehyed (MDA) activity while enhanced Superoxide Dismutase (SOD) activity. High dose of TG-6 improved the hypoxia injury of cardiomyocytes induced by sodium dithionite (Na?S?O?), enhanced the viability and decreased the [Ca²?]i. It also down-regulated the expression of Kv1.4 and increased the expression of Kv4.2 and Kv4.3, so it might through regulating the expression of the transient outward potassium current (Ito) to improve the cardiac function. PMID:22425651

Zhou, Yi; Gong, Guoqing; Yang, Wenhui; Wang, Yin; Xu, Jing; Xu, Yungen

2012-05-15

428

Aqueous ethylenediamine for CO(2) capture.  

PubMed

Aqueous ethylenediamine (EDA) has been investigated as a solvent for CO(2) capture from flue gas. EDA can be used at 12 M (mol kg(-1) H(2)O) with an acceptable viscosity of 16 cP (1 cP=10(-3) Pa s) with 0.48 mol CO(2) per equivalent of EDA. Similar to monoethanolamine (MEA), EDA can be used up to 120 degrees C in a stripper without significant thermal degradation. Inhibitor A will effectively eliminate oxidative degradation. Above 120 degrees C, loaded EDA degrades with the production of its cyclic urea and other related compounds. Unlike piperazine, when exposed to oxidative degradation, EDA does not result in excessive foaming. Over much of the loading range, the CO(2) absorption rate with 12 M EDA is comparable to 7 M MEA. However, at typical rich loading, 12 M EDA absorbs CO(2) 2 times slower than 7 M MEA. The capacity of 12 M EDA is 0.72 mol CO(2)/(kg H(2)O+EDA) (for P(CO(2) )=0.5 to 5 kPa at 40 degrees C), which is about double that of MEA. The apparent heat of CO(2) desorption in EDA solution is 84 kJ mol(-1) CO(2); greater than most other amine systems. PMID:20677204

Zhou, Shan; Chen, Xi; Nguyen, Thu; Voice, Alexander K; Rochelle, Gary T

2010-08-23

429

Inhibition of neuronal dopamine uptake by some antiallergic drugs.  

PubMed

The effects of 10 antiallergic drugs (astemizole, azelastine, ebastine, emedastine, epinastine, ketotifen, oxatomide, terfenadine, pemirolast and tranilast) on neuronal dopamine uptake were examined. Some drugs examined showed a concentration-dependent inhibition of [3H]dopamine uptake into synaptosomal preparations of the rat striatum. The inhibition constant (Ki) values were 231-876 nM for ebastine, terfenadine, oxatomide and astemizole. The specific binding of [3H] (1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine) (GBR12935) to the rat striatal membranes was also inhibited by these antiallergic drugs. There was a good correlation between the degrees of inhibition of [3H]dopamine uptake and [3H]GBR12935 binding. Then, the behavioral excitement induced by L-DOPA (100 mg/kg, s.c.) plus pargyline hydrochloride (80 mg/kg, i.p.) in mice was significantly enhanced by i.p. treatment with ebastine (10 mg/kg) and astemizole (5 mg/kg). These results suggest that the neuronal dopamine uptake is inhibited by some antiallergic drugs, especially ebastine. PMID:9696404

Matsunaga, K; Sato, T; Shuto, H; Tsuruta, Y; Suemaru, K; Gomita, Y; Oishi, R

1998-06-01

430

Three organically templated magnesium sulfates: Chemical preparation, hydrogen-bonded structures and thermal behavior  

NASA Astrophysics Data System (ADS)

Three new organically templated magnesium sulfates using ethylenediamine, dabco and piperazine have been synthesized by the slow evaporation method and structurally characterized by single-crystal X-ray diffraction. The chemical purity of the products and the presence of the different entities building the compounds were tested by the EDAX measurements, chemical analysis of the elements and the IR spectroscopy. Compound (I), (C2H10N2)[Mg(SO4)2(H2O)4], crystallizes in the triclinic system, space group P -1, while both hybrid materials (C4H12N2)[Mg(H2O)6](SO4)2 (II) and (C6H14N2)[Mg(H2O)6](SO4)2 (III) adopt another structure type and they crystallize in the monoclinic system, space group C2/c. The three supramolecular compounds are built from anions and cations linked together through a 3-D hydrogen bond network. The thermal decomposition of precursors, studied by thermogravimetric analysis (TG) and temperature-dependent X-ray diffraction (TDXD), show successive intermediate hydrates and crystalline anhydrous compounds upon dehydration.

Rekik, Walid; Naïli, Houcine; Mhiri, Tahar; Bataille, Thierry

2012-10-01

431

Construction of two novel indium phosphites with (3,6)- and (3,5)-connected frameworks: Synthesis, structure and characterization  

SciTech Connect

Two novel anionic indium phosphites, formulated as [H{sub 3}O][In(HPO{sub 3}){sub 2}] (1) and [C{sub 4}H{sub 12}N{sub 2}][In{sub 2}(HPO{sub 3}){sub 3}(C{sub 2}O{sub 4})] (2), were prepared under hydrothermal conditions by using piperazine (PIP) as a structure-directing agent (SDA). Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 crystallize in the hexagonal space group P6{sub 3}mc (No. 186) and orthorhombic space group Cmcm (No. 63), respectively. Compound 1, constructed from InO{sub 6} octahedra and HPO{sub 3} pseudo-pyramids, exhibits a rare (3,6)-connected layer structure with kgd (Kagome dual) topology. Compound 2, on the other hand, features a 3D phosphite-oxalate hybrid structure with intersecting 8- and 12-MRs channels. From a topological perspective 2 can be regarded as a (3, 5)-connected binodal net with the Schlaefli symbol (4{sup 2}.6)(4{sup 2}.6{sup 5}.8{sup 3}). Highlights: Black-Right-Pointing-Pointer Two novel indium phosphite and indium phosphite-oxalate hybrid compounds are synthesized. Black-Right-Pointing-Pointer (3, 6)-connected layer structure with kgd topology. Black-Right-Pointing-Pointer (3,5)-connected binodal net with the Schlaefli symbol (4{sup 2}.6)(4{sup 2}.6{sup 5}.8{sup 3}).

Li Huiduan [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Department of Chemistry and Life Science, Chuxiong Normal University, Chuxiong 675000 (China); Zhang Lirong; Huo Qisheng [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Liu Yunling, E-mail: yunling@jlu.edu.cn [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China)

2013-01-15

432

Antimycobacterial Activities of Novel 5-(1H-1,2,3-Triazolyl)Methyl Oxazolidinones  

PubMed Central

The antibacterial activities of a series of triazolyl oxazolidinones against Mycobacterium tuberculosis strain in vitro and in vivo in a mice model are presented. Most active compounds were noncytotoxic against VERO cells with acceptable selectivity indexes (SI) as measures of compound tolerability. Structure activity relationships (SARs) revealed that analogs with alkylcarbonyl (IC90: < 0.2 to 0.422??g/mL) and arylcarbonyl (IC90: < 0.2 to 2.103??g/mL) groups at the piperazine 4N-position-displayed potent antimycobacterium activities, comparable to the methanesulfonyl (IC90: < 0.2??g/mL) analog, linezolid (IC90: < 0.2??g/mL), and isoniazid (IC90: < 0.034??g/mL). The furanylcarbonyl derivative also displayed potent activity, while the arylsulfonyl analogs were inactive. Of the triazolyl oxazolidinones, the morpholino (PH-27) derivative with medium bioavailability in plasma was most active in vivo, but relatively less efficacious than isoniazid. PMID:22577542

Phillips, Oludotun Adebayo; Udo, Edet Ekpenyong; Varghese, Reny

2012-01-01

433

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The stripper model with Aspen Custom Modeler and careful optimization of solvent rate suggests that 7 m MEA and 5 m K+/2.5 m PZ will be practically equivalent in energy requirement and optimum solution capacity. The multipressure stripper reduces energy consumption by 15% with a maximum pressure of 5 atm. The use of vanadium as a corrosion inhibitor will carry little risk of long-term environmental or health effects liability, but the disposal of solvent with vanadium will be subject to regulation, probably as a hazardous waste. Analysis of the pilot plant data from Campaign 1 has given values of the mass transfer coefficient consistent with the rate data from the wetted wall column. With a rich end pinch, 30% MEA should provide a capacity of 1.3-1.4 mole CO{sub 2}/kg solvent.

Gary T. Rochelle; Eric Chen; Jennifer Lu; Babatunde Oyenekan; Ross Dugas

2004-11-08

434

PITPs as Targets for Selectively Interfering With Phosphoinositide Signaling in Cells  

PubMed Central

Sec14-like phosphatidylinositol transfer proteins (PITPs) integrate diverse territories of intracellular lipid metabolism with stimulated phosphatidylinositol-4-phosphate production, and are discriminating portals for interrogating phosphoinositide signaling. Yet, neither Sec14-like PITPs, nor PITPs in general, have been exploited as targets for chemical inhibition for such purposes. Herein, we validate the first small molecule inhibitors (SMIs) of the yeast PITP Sec14. These SMIs are nitrophenyl(4-(2-methoxyphenyl)piperazin-1-yl)methanones (NPPMs), and are effective inhibitors in vitro and in vivo. We further establish Sec14 is the sole essential NPPM target in yeast, that NPPMs exhibit exquisite targeting specificities for Sec14 (relative to related Sec14-like PITPs), propose a mechanism for how NPPMs exert their inhibitory effects, and demonstrate NPPMs exhibit exquisite pathway selectivity in inhibiting phosphoinositide signaling in cells. These data deliver proof-of-concept that PITP-directed SMIs offer new and generally applicable avenues for intervening with phosphoinositide signaling pathways with selectivities superior to those afforded by contemporary lipid kinase-directed strategies. PMID:24292071

Nile, Aaron H.; Tripathi, Ashutosh; Yuan, Peihua; Mousley, Carl J.; Suresh, Sundari; Wallace, Iain Michael; Shah, Sweety D.; Pohlhaus, Denise Teotico; Temple, Brenda; Nislow, Corey; Giaever, Guri; Tropsha, Alexander; Davis, Ronald W.; St Onge, Robert P.; Bankaitis, Vytas A.

2013-01-01

435

Chemical modifications of antisense morpholino oligomers enhance their efficacy against Ebola virus infection.  

PubMed

Phosphorodiamidate morpholino oligomers (PMOs) are uncharged nucleic acid-like molecules designed to inactivate the expression of specific genes via the antisense-based steric hindrance of mRNA translation. PMOs have been successful at knocking out viral gene expression and replication in the case of acute viral infections in animal models and have been well tolerated in human clinical trials. We propose that antisense PMOs represent a promising class of therapeutic agents that may be useful for combating filoviral infections. We have previously shown that mice treated with a PMO whose sequence is complementary to a region spanning the start codon of VP24 mRNA were protected against lethal Ebola virus challenge. In the present study, we report on the abilities of two additional VP24-specific PMOs to reduce the cell-free translation of a VP24 reporter, to inhibit the in vitro replication of Ebola virus, and to protect mice against lethal challenge when the PMOs are delivered prior to infection. Additionally, structure-activity relationship evaluations were conducted to assess the enhancement of antiviral efficacy associated with PMO chemical modifications that included conjugation with peptides of various lengths and compositions, positioning of conjugated peptides to either the 5' or the 3' terminus, and the conferring of charge modifications by the addition of piperazine moieties. Conjugation with arginine-rich peptides greatly enhanced the antiviral efficacy of VP24-specific PMOs in infected cells and mice during lethal Ebola virus challenge. PMID:19223614

Swenson, Dana L; Warfield, Kelly L; Warren, Travis K; Lovejoy, Candace; Hassinger, Jed N; Ruthel, Gordon; Blouch, Robert E; Moulton, Hong M; Weller, Dwight D; Iversen, Patrick L; Bavari, Sina

2009-05-01

436

Sulfomethylation of Di-, Tri-, and polyazamacrocycles: a new route to entry of mixed-side-chain macrocyclic chelates.  

PubMed

The sulfomethylation of piperazine and the polyazamacrocycles, [9]aneN3, [12]aneN3, [12]aneN4, and [18]aneN6 with formaldehyde bisulfite in aqueous medium at various pH values is described. The number of methanesulfonate groups introduced into these structures was found to be largely determined by pH. At neutral pH, disubstituted products of [9]aneN3, [12]aneN3, [12]aneN4 are formed and, in the latter case, the trans-1,7-bis(methanesulfonate) isomer was predominant. Similarly, a single, symmetrical trisubstituted product was formed with [18]aneN6 at neutral pH. Monomethanesulfonated products of these same polyaza compounds were formed at more acidic pH's. These sulfomethylated products were used as an entry into a series of mono- and diacetate, phosphonate, and phosphinate derivatives of [9]aneN3, [12]aneN3, and [12]aneN4. The sulfonate groups may be converted to acetates without isolation of intermediates by using cyanide to displace the sulfonate(s) followed by acidic hydrolysis. The aminomethanesulfonates may also be oxidatively hydrolyzed by using aqueous triiodide as a prelude to the preparation of aminomethanephosphonates or aminomethanephosphinates. PMID:1334438

van Westrenen, J; Sherry, A D

1992-01-01

437

Simultaneous determination of a novel diphenylpiperazine calcium channel blocker and its four metabolites in rat liver microsomes by liquid chromatography tandem mass spectrometry.  

PubMed

Dipfluzine hydrochloride (Dip), a novel diphenylpiperazine calcium channel blocker, has revealed the characteristics of a promising candidate for the treatment of cerebral vascular diseases in preclinical studies. Our research identified and quantified Dip and its 4 metabolites (M1, M2, M4 and M5) in rat liver microsomes by liquid chromatography tandem mass spectrometry. The results showed that Dip was firstly metabolized to M1 and M5 by 1- and 4-dealkylation from a piperazine nitrogen, and then the latter was subsequently metabolized to M2 and M4. The concentrations of Dip, M1, M2 and M5 were 557.3 ± 26.3, 854.3 ± 46.0, 2796.7± 126.9, 2473.3 ± 82.6 and 4.0 ± 0.4, 2.4 ± 0.1, 318.2 ± 8.7 and 27.4 ± 1.5 ng/ml in male and female rats, respectively. M4 (404.2 ± 22.2 ng/ml) was detected only in males not in females, suggesting that there is gender difference in the metabolism of Dip. PMID:22473133

Guo, Wei; Kong, Dezhi; Du, Yingfeng; Shi, Xiaowei; Wang, Wei; Wang, Yongli

2012-01-01

438

Novel progesterone receptor modulators with gene selective and context-dependent partial agonism.  

PubMed

Progesterone receptor (PR) modulators are used in contraception and post-menopausal hormone therapy, and are under clinical development for reproductive disorders such as uterine fibroids and endometriosis. Development of tissue selective PR modulators (SPRMs) with reduced side effects and improved pharmacology represents a large unmet medical need in the area of women's health. One approach to addressing this need is to focus on the two PR isoforms PR-A and PR-B. In vitro and in vivo studies have revealed both distinct as well as overlapping gene regulation and functional responses of the two PR isoforms that suggests that PR-A selective modulators may retain a desired biological profile. We have identified a chemical series of 4-(4-chlorophenyl)-substituted piperazine carbimidothioic acid esters (PCEs) that have partial PR agonist activity and selectively activate some PR-A isoform regulated genes in T47D cells. However, full microarray analysis in these cells does not predict a global isoform selective profile for these compounds, but rather a unique gene-selective profile is observed relative to steroidal progestins. Using multiplexed peptide interaction profiling and co-activator recruitment assays we find that the mechanism of partial agonism is only partly defined by the ability to recruit known co-activators or peptides but also depends on the cell and promoter context of the gene under investigation. The data demonstrate global consequences of mechanistic and functional differences that can lead to selective biological responses of novel steroid receptor modulators. PMID:19013437

Berrodin, Thomas J; Jelinsky, Scott A; Graciani, Nilsa; Butera, John A; Zhang, Zhiming; Nagpal, Sunil; Winneker, Richard C; Yudt, Matthew R

2009-01-15

439

Extrapyramidal adverse drug reactions associated with trimetazidine: a series of 21 cases.  

PubMed

Over the last few years, a number of cases of extrapyramidal disorders associated with trimetazidine (TMZ) use has been reported. Here, we report on a series of 21 cases. All but one of the patients (mean age 74) had been taking TMZ for several years. The indication for prescription of TMZ could not be identified in seven cases. The TMZ-associated adverse drug reactions were typical parkinsonism (akinesia and/or rigidity and/or rest tremor) in 17 cases, gait disorders in three cases (one with orthostatic tremor), and restless leg syndrome in one case. Discontinuation of TMZ led to complete disappearance of the symptoms in 16 cases and a significant reduction in the five other patients. TMZ has the same piperazine core as the dopamine antagonists flunarizine and cinnarizine (both of which have been reported to induce extrapyramidal symptoms). Hence, striatal D2 receptor blockade could result in the onset or the worsening of extrapyramidal disorders. Even though this adverse drug reaction is now listed in TMZ's Summary of Product Characteristics (because of the initial reports), the risk remains poorly known by clinicians. There is a need to raise awareness of this phenomenon and to reassess TMZ 's risk-benefit ration, especially in the elderly. PMID:22044594

Masmoudi, Kamel; Masson, Henri; Gras, Valérie; Andréjak, Michel

2012-04-01

440

Determination of methyl isocyanate in outdoor residential air near metam-sodium soil fumigations.  

PubMed

The soil fumigant metam-sodium (CH3NHCS2Na) produces the bioactive respiratory irritant methyl isothiocyanate (MITC). Recent laboratory gas-phase oxidative studies indicate that MITC rapidly transforms to the more toxic methyl isocyanate (MIC) in the lower atmosphere. Inhalation exposure risks from MITC plus MIC may therefore be an occupational worker and/or bystander health concern. To address this concern, MIC was monitored, along with MITC, in outdoor residential air in Washington state during the peak fall metam fumigation season. XAD-7 cartridges, coated with 1-(2-pyridyl)piperazine, were developed to retain MIC as its stable substituted urea derivative. Of the 68 residential air measurements of MIC, 15 (22%) were observed to be above the California Environmental Protection Agency's chronic inhalation reference level of 1 ?g/m(3), with an observed maximum MIC air concentration of 4.4 ?g/m(3). This study indicates MIC air concentrations can be anticipated along with MITC in residential air where seasonal metam soil fumigant applications occur. PMID:25144617

Woodrow, James E; LePage, Jane T; Miller, Glenn C; Hebert, Vincent R

2014-09-10

441

A study of the swelling and model protein release behaviours of radiation-formed poly(N-vinyl 2-pyrrolidone-co-acrylic acid) hydrogels  

NASA Astrophysics Data System (ADS)

Hydrogels were prepared from poly(acrylic acid-co-N-vinyl pyrrolidone), poly(AA-co-VP) and mixtures of poly(AA-co-VP) and poly(ethylene oxide), PEO, by gamma radiolysis of aqueous solutions of the AA and VP monomers containing ethylene glycol dimethacrylate, EGDMA, as crosslinker and PEO. The AA/VP composition range of the poly(AA-co-VP) was XAA 0.7-0.9. The swelling behaviours of the hydrogels from the dry state were investigated in water (pH 6.5) and 50 mM 4-(2-hydroxyethyl)piperazine-1-ethylsulfonic acid buffer, HEPES buffer, at pH 7.4 and 295 K. The effects of poly(AA-co-VP) composition, crosslinker mole fraction and the presence of PEO on the equilibrium swelling ratio for the gels was examined. The kinetics of the release of a model protein, horseradish peroxidase, HRP, from the hydrogels in water were also studied at 295 K.

Wang, David; Hill, David J. T.; Rasoul, Firas; Whittaker, Andrew K.

2011-02-01

442

Detection of new psychoactive substance use among emergency room patients: Results from the Swedish STRIDA project.  

PubMed

The "STRIDA" project monitors the occurrence and trends of new psychoactive substances (NPS; "Internet drugs/designer drugs/legal highs") in Sweden, and collects information about their clinical symptoms, toxicity and associated health hazards. The initial results of the project documented a widespread use of many different NPS by mainly adolescents and young (age range 13-63 years, median 20), male (79%) adults, among cases of drug intoxications presenting at emergency departments and intensive care units across the country. The new substances were identified in samples of urine and blood by a multi-component LC-MS/MS method, and the severity of clinical symptoms were graded by the Poisoning Severity Score (PSS). Of the initial 189 samples submitted for laboratory investigation, 156 (83%) tested positive for at least one drug. Besides classical substances such as ethanol, cannabis and amphetamines, many NPS were detected comprising synthetic cannabinoid receptor agonists ("Spice"), piperazines, substituted phenethylamines, synthetic cathinones, hallucinogenic tryptamines, piperidines, opioid related substances, ketamine and related substances, and GABA analogues (in total more than 50 substances). About half of the cases were demonstrated to be multiple drug intoxications, sometimes making it hard to associate the clinical presentations with one specific substance. In conclusion, the STRIDA project has documented use of a broad variety of NPS among mainly young people all over Sweden. PMID:24726531

Helander, Anders; Bäckberg, Matilda; Hultén, Peter; Al-Saffar, Yasir; Beck, Olof

2014-10-01

443

A bifunctional Pd/MgO solid catalyst for the one-pot selective N-monoalkylation of amines with alcohols.  

PubMed

It has been found that a bifunctional metal Pd/base (MgO) catalyst performs the selective monoalkylation of amines with alcohols. The reaction goes through a series of consecutive steps in a cascade mode that involves: 1) the abstraction of hydrogen from the alcohol that produces the metal hydride and the carbonyl compound; 2) condensation of the carbonyl with the amine to give an imine, and 3) hydrogenation of the imine with the surface hydrogen atoms from the metal hydride. Based on isotopic and spectroscopic studies and on the rate of each elementary step, a global reaction mechanism has been proposed. The controlling step of the process is the hydride transfer from the metal to the imine. By changing the crystallite size of the Pd, it is demonstrated that this is a structure-sensitive reaction, whereas the competing processes that lead to subproducts are not. On these bases, a highly selective catalyst has been obtained with Pd crystallite size below 2.5 nm in diameter. The high efficiency of the catalytic system has allowed us to extend the process to the one-pot synthesis of piperazines. PMID:19904774

Corma, Avelino; Ródenas, Tania; Sabater, María J

2010-01-01

444

Mechanistic insight into ligand binding to G-quadruplex DNA  

PubMed Central

Specific guanine-rich regions in human genome can form higher-order DNA structures called G-quadruplexes, which regulate many relevant biological processes. For instance, the formation of G-quadruplex at telomeres can alter cellular functions, inducing apoptosis. Thus, developing small molecules that are able to bind and stabilize the telomeric G-quadruplexes represents an attractive strategy for antitumor therapy. An example is 3-(benzo[d]thiazol-2-yl)-7-hydroxy-8-((4-(2-hydroxyethyl)piperazin-1-yl)methyl)-2H-chromen-2-one (compound 1), recently identified as potent ligand of the G-quadruplex [d(TGGGGT)]4 with promising in vitro antitumor activity. The experimental observations are suggestive of a complex binding mechanism that, despite efforts, has defied full characterization. Here, we provide through metadynamics simulations a comprehensive understanding of the binding mechanism of 1 to the G-quadruplex [d(TGGGGT)]4. In our calculations, the ligand explores all the available binding sites on the DNA structure and the free-energy landscape of the whole binding process is computed. We have thus disclosed a peculiar hopping binding mechanism whereas 1 is able to bind both to the groove and to the 3’ end of the G-quadruplex. Our results fully explain the available experimental data, rendering our approach of great value for further ligand/DNA studies. PMID:24753420

Di Leva, Francesco Saverio; Novellino, Ettore; Cavalli, Andrea; Parrinello, Michele; Limongelli, Vittorio

2014-01-01

445

AdeRS combination codes differentiate the response to efflux pump inhibitors in tigecycline-resistant isolates of extensively drug-resistant Acinetobacter baumannii.  

PubMed

Tigecycline (TGC)-resistant extensively drug-resistant Acinetobacter baumannii (XDRAB) is an increasing threat in regard to nosocomial infections. The resistance-nodulation-cell division (RND) efflux pump has played an important role in TGC resistance. In this study, total 81 TGC-resistant XDRAB isolates were analyzed for their responses to the efflux pump inhibitor 1-(1-naphthylmethyl)-piperazine (NMP). We found that NMP could reduce by 4-fold or greater than 4-fold the minimum inhibitory concentration (MIC) of TGC in 45 isolates (55.6 %). After typing with pulsed-field gel electrophoresis (PFGE), group A appeared to be the major cluster with good synergistic response to NMP. Transcripts of the AdeABC efflux pump gene were consistently more correlated with TGC resistance than transcripts of the AdeFGJ or AdeIJK efflux pump genes in these isolates. Of the 81 isolates, the amino acid sequences of AdeR and AdeS were further classified and combined into 31 different codes. Although the dissemination of TGC-resistant XDRAB isolates was genetically diverse in our hospital, their responses to NMP conversion were still strain-dependent. We found that AdeRS combination codes were better than PFGE typing in separating groups of isolates with different sensitivity to NMP conversion. PMID:24939621

Sun, J-R; Perng, C-L; Lin, J-C; Yang, Y-S; Chan, M-C; Chang, T-Y; Lin, F-M; Chiueh, T-S

2014-12-01

446

Particle aggregation by positive dielectrophoresis  

E-print Network

Particle aggregates are formed with viable yeast cells (Saccharomyces cerevisiae) and bacterial cells (Escherichia coli and Micrococcus luteus), and are assembled in an interdigitated-castelled microelectrode using positive dielectrophoresis with an alternating current sinusoidal voltage of 2-20 V peak-peak at 1 MHz. The height of S. cerevisiae aggregates are increased by the addition of the ampholytes N-[2-hydroxyethyl] piperazine-n'-[2-ethanesulfonic acid] (HEPES) or e-aminocaproic acid (EACA) due to the resulting rise in permittivity of the aqueous solution. The mean height of S. cerevisiae aggregates in the presence of 1 M HEPES was 25.7 % higher than achieved in an ampholyte-free solution. Based on the results obtained, a next-generation triangular grooved microelectrode is proposed as an alternative to the interdigitated-castelled microelectrode. This innovation could mark a paradigm shift from aggregating particles at specific regions of high electric strength (e.g. electrode edge) towards a layer by layer aggregation of particles along a microelectrode.

Charles Osarinmwian

2013-12-05

447

Different effects of selective dopamine uptake inhibitors, GBR 12909 and WIN 35428 on HIV-1 Tat toxicity in rat fetal midbrain neurons  

PubMed Central

Drug abuse is a risk factor for neurological complications in HIV infection. Cocaine has been shown to exacerbate HIV-associated brain pathology and enhance neurotoxicity of HIV-1 Tat and gp120 proteins. In this study, we found that the selective inhibitor of dopamine transporter (DAT) function, 1-[2-[bis(4- fluorophenyl) methoxy]ethyl]-4-(3-phenylpropyl) piperazine (GBR 12909, vanoxerine), but not the selective inhibitors of serotonin and norepinephrine (SERT and NET) transporters, sertraline and nizoxetine, emulated cocaine-mediated enhancement of Tat neurotoxicity in rat fetal midbrain primary cell cultures. Similar to cocaine, the significant increase of Tat toxicity in midbrain cell cultures was observed at micromolar dose (5 ?M) of GBR 12909. However, different doses of another selective dopamine uptake inhibitor, WIN 35428 did not affect Tat neurotoxicity. The study supports the hypothesis that changes in control of dopamine (DA) homeostasis are important for the cocaine-mediated enhancement of HIV-1 Tat neurotoxicity. Our results also demonstrate that the inhibitors of DA uptake, which can bind to different domains of DAT, differ in their ability to mimic synergistic toxicity of cocaine and HIV-1 Tat in the midbrain cell culture. PMID:18606182

Aksenov, Michael Y.; Aksenova, Marina V.; Silvers, Janelle M.; Mactutus, Charles F.; Booze, Rosemarie M.

2014-01-01

448

Anti-AIDS Agents 90. Novel C-28 Modified Bevirimat Analogs as Potent HIV Maturation Inhibitors  

PubMed Central

In a continuing study of bevirimat (2), the anti-HIV-maturation clinical trials agent, 28 new betulinic acid (BA, 1) derivatives were designed and synthesized. Among these compounds, 17, with a C-28 MEM ester moiety, and 22, with a C-28 ethyl hexanoate, increased the anti-HIV replication activity compared with 2 by two-fold, while compounds 40–41 and 48–49, with C-28 piperazine or piperidine amide substitutions, increased the activity by three- to fifteen-fold. The best new compound 41 exhibited an anti-HIV IC50 value of 0.0059 ?M, compared with 0.087 ?M for 2. All of the active compounds showed only anti-maturation effects, as confirmed by TZM-bl assay, in blocking the HIV replication. The results suggest that proper C-28 substitutions can further enhance the anti-maturation activity of 2, without any anti-entry effects. Thus, 41 may serve as a promising new lead for development of anti-AIDS clinical trial candidates. PMID:22978745

Qian, Keduo; Bori, Ibrahim D.; Chen, Chin-Ho; Huang, Li; Lee, Kuo-Hsiung

2012-01-01

449

pH-Responsive Artemisinin Derivatives and Lipid Nanoparticle Formulations Inhibit Growth of Breast Cancer Cells In Vitro and Induce Down-Regulation of HER Family Members  

PubMed Central

Artemisinin (ART) dimers show potent anti-proliferative activities against breast cancer cells. To facilitate their clinical development, novel pH-responsive artemisinin dimers were synthesized for liposomal nanoparticle formulations. A new ART dimer was designed to become increasingly water-soluble as pH declines. The new artemisinin dimer piperazine derivatives (ADPs) remained tightly associated with liposomal nanoparticles (NPs) at neutral pH but were efficiently released at acidic pH's that are known to exist within solid tumors and organelles such as endosomes and lysosomes. ADPs incorporated into nanoparticles down regulated the anti-apoptotic protein, survivin, and cyclin D1 when incubated at low concentrations with breast cancer cell lines. We demonstrate for the first time, for any ART derivative, that ADP NPs can down regulate the oncogenic protein HER2, and its counterpart, HER3 in a HER2+ cell line. We also show that the wild type epidermal growth factor receptor (EGFR or HER1) declines in a triple negative breast cancer (TNBC) cell line in response to ADP NPs. The declines in these proteins are achieved at concentrations of NP109 at or below 1 µM. Furthermore, the new artemisinin derivatives showed improved cell-proliferation inhibition effects compared to known dimer derivatives. PMID:23516601

Zhang, Yitong J.; Gallis, Byron; Taya, Michio; Wang, Shusheng; Ho, Rodney J. Y.; Sasaki, Tomikazu

2013-01-01

450

Fe(III) Reduction and U(VI) Immobilization by Paenibacillus sp. Strain 300A, Isolated from Hanford 300A Subsurface Sediments  

PubMed Central

A facultative iron-reducing [Fe(III)-reducing] Paenibacillus sp. strain was isolated from Hanford 300A subsurface sediment biofilms that was capable of reducing soluble Fe(III) complexes [Fe(III)-nitrilotriacetic acid and Fe(III)-citrate] but unable to reduce poorly crystalline ferrihydrite (Fh). However, Paenibacillus sp. 300A was capable of reducing Fh in the presence of low concentrations (2 ?M) of either of the electron transfer mediators (ETMs) flavin mononucleotide (FMN) or anthraquinone-2,6-disulfonate (AQDS). Maximum initial Fh reduction rates were observed at catalytic concentrations (<10 ?M) of either FMN or AQDS. Higher FMN concentrations inhibited Fh reduction, while increased AQDS concentrations did not. We also found that Paenibacillus sp. 300A could reduce Fh in the presence of natural ETMs from Hanford 300A subsurface sediments. In the absence of ETMs, Paenibacillus sp. 300A was capable of immobilizing U(VI) through both reduction and adsorption. The relative contributions of adsorption and microbial reduction to U(VI) removal from the aqueous phase were ?7:3 in PIPES [piperazine-N,N?-bis(2-ethanesulfonic acid)] and ?1:4 in bicarbonate buffer. Our study demonstrated that Paenibacillus sp. 300A catalyzes Fe(III) reduction and U(VI) immobilization and that these reactions benefit from externally added or naturally existing ETMs in 300A subsurface sediments. PMID:22961903

Ahmed, Bulbul; Cao, Bin; McLean, Jeffrey S.; Ica, Tuba; Dohnalkova, Alice; Istanbullu, Ozlem; Paksoy, Akin; Fredrickson, Jim K.

2012-01-01

451

The distributional nexus of choroid plexus to cerebrospinal fluid, ependyma and brain: toxicologic/pathologic phenomena, periventricular destabilization, and lesion spread.  

PubMed

Bordering the ventricular cerebrospinal fluid (CSF) are epithelial cells of choroid plexus (CP), ependyma and circumventricular organs (CVOs) that contain homeostatic transporters for mediating secretion/reabsorption. The distributional pathway ("nexus") of CP-CSF-ependyma-brain furnishes peptides, hormones, and micronutrients to periventricular regions. In disease/toxicity, this nexus becomes a conduit for infectious and xenobiotic agents. The sleeping sickness trypanosome (a protozoan) disrupts CP and downstream CSF-brain. Piperamide is anti-trypanosomic but distorts CP epithelial ultrastructure by engendering hydropic vacuoles; this reflects phospholipidosis and altered lysosomal metabolism. CP swelling by vacuolation may occlude CSF flow. Toxic drug tools delineate injuries to choroidal compartments: cyclophosphamide (vasculature), methylcellulose (interstitium), and piperazine (epithelium). Structurally perturbed CP allows solutes to penetrate the ventricles. There, CSF-borne pathogens and xenobiotics may permeate the ependyma to harm neurogenic stem cell niches. Amoscanate, an anti-helmintic, potently injures rodent ependyma. Ependymal/brain regions near CP are vulnerable to CSF-borne toxicants; this proximity factor links regional barrier breakdown to nearby periventricular pathology. Diverse diseases (e.g., African sleeping sickness, multip