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Sample records for dien bien phu

  1. Crystal structure of the Pseudomonas aeruginosa cytoplasmic heme binding protein, Apo-PhuS.

    PubMed

    Tripathi, Sarvind; O'Neill, Maura J; Wilks, Angela; Poulos, Thomas L

    2013-11-01

    Iron is an essential element to all living organisms and is an important determinant of bacterial virulence. Bacteria have evolved specialized systems to sequester and transport iron from the environment or host. Pseudomonas aeruginosa, an opportunistic pathogen, uses two outer membrane receptor mediated systems (Phu and Has) to utilize host heme as a source of iron. PhuS is a 39 kDa soluble cytoplasmic heme binding protein which interacts and transports heme from the inner membrane heme transporter to the cytoplasm where it is degraded by heme oxygenase thus releasing iron. PhuS is unique among other cytoplasmic heme transporter proteins owing to the presence of three histidines in the heme binding pocket which can potentially serve as heme ligands. Out of the three histidine residues on the heme binding helix, His 209 is conserved among heme trafficking proteins while His 210 and His 212 are unique to PhuS. Here we report the crystal structure of PhuS at 1.98Å resolution which shows a unique heme binding pocket and oligomeric structure compared to other known cytoplasmic heme transporter and accounts for some of the unusual biochemical properties of PhuS. PMID:23973453

  2. A Conversation with Zoltan P. Dienes

    ERIC Educational Resources Information Center

    Sriraman, Bharath; Lesh, Richard

    2007-01-01

    The name of Zoltan P. Dienes (1916- ) stands with those of Jean Piaget, Jerome Bruner, Edward Begle, and Robert Davis as a legendary figure whose work left a lasting impression on the field of mathematics education. Dienes' name is synonymous with the multibase blocks that he invented for the teaching of place value. Among numerous other things,…

  3. Predictors for dioxin accumulation in residents living in Da Nang and Bien Hoa, Vietnam, many years after Agent Orange use.

    PubMed

    Pham, Diem T; Nguyen, Hang M; Boivin, Thomas G; Zajacova, Anna; Huzurbazar, Snehalata V; Bergman, Harold L

    2015-01-01

    Agent Orange (AO) was the main defoliant used by the US in Vietnam from 1961 to 1971; AO was contaminated with dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD). Three major dioxin “hot spots” remain from previous AO storage and use at former US bases at Bien Hoa, Da Nang, and Phu Cat, posing potential health risks for Vietnamese living on or near these hot spots. We evaluated potential risk factors contributing to serum TCDD levels in Vietnamese residents at and near contaminated sites in Da Nang and Bien Hoa, Vietnam. We used multiple linear regression to analyze possible associations of blood dioxin concentrations with demographic, socioeconomic, lifestyle, and dietary risk factors for residents living on or near these hot spots. For the Da Nang study, fish farming on the site, living on property flooded from monsoon rains, and age were among the factors showing significant positive associations with serum TCDD concentrations. For the Bien Hoa study, fish farmers working at this site and their immediate family members had significantly higher serum TCDD concentrations. Our results suggest that water-related activities, especially fish-farming, at the hot spots increased the risk of exposure to dioxin. PMID:25463251

  4. Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea

    SciTech Connect

    Lee, G.H.; Watkins, J.S.

    1996-12-31

    The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressive interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.

  5. Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea

    SciTech Connect

    Lee, G.H. ); Watkins, J.S. )

    1996-01-01

    The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressive interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.

  6. Spectroscopic Determination of Distinct Heme Ligands in Outer-Membrane Receptors PhuR and HasR of Pseudomonas aeruginosa

    PubMed Central

    Smith, Aaron D.; Modi, Anuja R.; Sun, Shengfang; Dawson, John H.; Wilks, Angela

    2015-01-01

    Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonas heme uptake) and HasR (heme assimilation system). The HasR receptor acquires heme through interaction with a secreted hemophore, HasAp. The non-hemophore-dependent PhuR is encoded along with proteins required for heme translocation into the cytoplasm. Herein, we report the isolation and characterization of the HasR and PhuR receptors. Absorption and MCD spectroscopy confirmed that, similar to other Gram-negative OM receptors, HasR coordinates heme through the conserved N-terminal plug His-221 and His-624 of the surface-exposed FRAP-loop. In contrast, PhuR showed distinct absorption and MCD spectra consistent with coordination through a Tyr residue. Sequence alignment of PhuR with all known Gram-negative OM heme receptors revealed a lack of a conserved His within the FRAP loop but two Tyr residues at positions 519 and 529. Site-directed mutagenesis and spectroscopic characterization confirmed Tyr-519 and the N-terminal plug His-124 provide the heme ligands in PhuR. We propose that PhuR and HasR represent nonredundant heme receptors capable of sensing and accessing heme across a wide range of physiological conditions on colonization and infection of the host. PMID:25849630

  7. A new species of Dixonius (Squamata: Gekkonidae) from Phu Quy Island, Vietnam.

    PubMed

    Botov, Andreas; Phung, Trung My; Nguyen, Truong Quang; Bauer, Aaron M; Brennan, Ian G; Ziegler, Thomas

    2015-01-01

    We describe a new species of Dixonius on the basis of five specimens from Phu Quy Island, Binh Thuan Province, in southern Vietnam. The new species can be distinguished from congeners based on molecular and morphological differences. Diagnostic features are: small size (SVL up to 44 mm); 7 or 8 supralabials; 11 or 12 rows of keeled tubercles on dorsum; 21-23 ventral scale rows; 5 or 6 precloacal pores in males; a canthal stripe running from rostrum through the eye and terminating behind the head; second pair of postmentals about one third to one half size of first pair; ground color of dorsum brown, with one or two rows of light yellow or orange spots in one or two rows along flanks, and irregular bands or a reticulated network of dark marks on dorsum. This is the fifth species of Dixonius known to occur in Vietnam. PMID:26624650

  8. Vietnam: An Historical Perspective.

    ERIC Educational Resources Information Center

    Shackford, Julie

    This book provides an overview of Vietnam's history prior to the U.S. presence there. The book begins with a chronology extending from prehistoric times to the defeat of the French at Dien Bien Phu in 1954. Each chapter provides background information along with a glossary, student activities, and project suggestions. Chapters include: (1)…

  9. Syntheses and properties of poly([6. 2]cyclophane-1,5-diene)s: Electroactive polymers

    SciTech Connect

    Guerrero, D.J.

    1993-01-01

    The synthesis and characterization of (E,E)-[6.2]-(2,5)thiophenophane-1,5-diene (2) is described. Ultraviolet and variable temperature [sup 1]H-nmr spectroscopy were used to deduce structural detail of 2 in solution. Cationic cyclopolymerization of 2 gave polymer 3 which has bridged thiophene rings pendant to the polymer backbone. Structural details of polymer 3 are largely based on comparison with its known benzene analogue (1), poly(2-vinylthiophene) (15) and poly(5-methyl-2-vinylthiophene) (17). The thermal and electronic properties of polymer 3 were compared to those of 15. Polymer 3 exhibited conductivity in the 10[sup [minus]3]-10[sup [minus]4] S/cm range when exposed to iodine vapor. Apparent energies of activation for conductivity in iodine saturated polymers 3 and 15 were calculated from conductivity temperature dependence measurements. Differences in conductivity behavior for iodine saturated polymers 1, 3, and 15 are discussed in terms of both charge generation and mobility. The effects of increasing the electric field on photoconductivity and mobility of 1 and 3 are discussed. Utilization of 1 and 3 in the construction of polymer based chemical sensors for iodine is demonstrated. A novel iodine promoted ring opening polymerization of [2,2]-(2,5)thiophenophane (TPP) is presented. Ft-ir studies of the resulting films revealed formation of a poly ((2,5)-thienylene ethylene) type structure. [2.2]-(2,5)-furanophane and [2.2]-(9,10)-anthracenophane treated similarly also gave the corresponding poly(arylene ethylene) polymers. [2.2]paracyclophane, 4-nitro-[2.2]paracyclophane, anti-[2.2]-(1,4)-naphthalenophane and (E,E)-[6.2]paracyclophane-1,5-diene did not give polymer in the presence of iodine. Electrochemical ring opening polymerization of TPP at a Pt anode suggests a radical cationic intermediate during polymerization.

  10. Integration ofhup cosmid pHU52 into the chromosomal DNA ofCicer-Rhizobium using Tn5 as an homologous sequence.

    PubMed

    Kunnimalaiyaan, M; Lodha, M L; Sreekumar, K R

    1992-11-01

    Cosmid pHU52, which carrieshup genes ofBradyrhizobium japonicum, has been integrated into theCicer-Rhizobium G36-84 genome via Tn5-mediated homologous recombination. Tn5 was inserted into both the cosmid pHU52 and the chromosome ofCicer-Rhizobium to provide a region of DNA homology, without affecting the expression of necessary genes. An incompatible plasmid, pPH1JI, was used to select those few cells that had undergone recombination. The integration of the cosmid was demonstrated by Southern blot analysis. Chromosomal integration of thehup genes maximized stability and minimized the potential for their horizontal transfer to other bacterial species. The integratedhup genes were found to expressex planta as well in nodules. The method described illustrates how a given gene can be stably integrated into the chromosome. PMID:24425601

  11. Palladium-catalysed hydroamidocarbonylation of 1,3-dienes.

    PubMed

    Li, Haoquan; Fang, Xianjie; Jackstell, Ralf; Neumann, Helfried; Beller, Matthias

    2016-06-01

    Herein, we report our recent result on the development of the selective catalytic method towards the synthesis of β,γ-unsaturated imides via Pd-catalysed hydroamidocarbonylation of conjugated dienes. Note that this reaction proceeds under acid additive free conditions. Various dienes, including those of high industrial value (e.g. isoprene, 1,3-butadiene), are shown to be compatible with our established method (28 examples, 40-99% yield), which leads to the corresponding β,γ-unsaturated imides in a highly efficient and atom-economic fashion. PMID:27169986

  12. Alkyl substituted [2.2]paracyclophane-1,9-dienes.

    PubMed

    Lidster, Benjamin J; Kumar, Dharam R; Spring, Andrew M; Yu, Chin-Yang; Helliwell, Madeleine; Raftery, James; Turner, Michael L

    2016-07-01

    [2.2]Paracyclophane-1,9-dienes substituted with n-octyl chains have been synthesised from the corresponding dithia[3.3]paracyclophanes using a benzyne induced Stevens rearrangement. The use of 2-(trimethylsilyl)phenyl trifluoromethanesulfonate and tetra-n-butylammonium fluoride as the in situ benzyne source gave significantly improved yields over traditional sources of benzyne and enabled the preparation of n-octyl substituted [2.2]paracyclophane-1,9-dienes on a multi-gram scale. PMID:27249777

  13. Process for crosslinking and extending conjugated diene-containing polymers

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor); Havens, Stephen J. (Inventor)

    1977-01-01

    A process using a Diels-Alder reaction which increases the molecular weight and/or crosslinks polymers by reacting the polymers with bisunsaturated dienophiles is developed. The polymer comprises at least 75% by weight based on the reaction product, has a molecular weight of at least 5000 and a plurality of conjugated 1,3-diene systems incorporated into the molecular structure. A dienophile reaction with the conjugated 1,3-diene of the polymer is at least 1% by weight based on the reaction product. Examples of the polymer include polyesters, polyamides, polyethers, polysulfones and copolymers. The bisunsaturated dienophiles may include bis-maleimides, bis maleic and bis tumaric esters and amides. This method for expanding the molecular weight chains of the polymers, preferable thermoplastics, is advantageous for processing or fabricating thermoplastics. A low molecular weight thermoplastic is converted to a high molecular weight plastic having improved strength and toughness for use in the completed end use article.

  14. Recent advances in stereoselective synthesis of 1,3-dienes.

    PubMed

    De Paolis, Michael; Chataigner, Isabelle; Maddaluno, Jacques

    2012-01-01

    The aim of this review is to present the latest developments in the stereoselective synthesis of conjugated dienes, covering the period 2005-2010. Since the use of this class of compounds is linked to the nature of their appendages (aryls, alkyls, electron-withdrawing, and heterosubstituted groups), the review has been categorized accordingly and illustrates the most representative strategies and mechanisms to access these targets. PMID:22527407

  15. The origin and evolution of skarn-forming fluids from the Phu Lon deposit, northern Loei Fold Belt, Thailand: Evidence from fluid inclusion and sulfur isotope studies

    NASA Astrophysics Data System (ADS)

    Kamvong, Teera; Zaw, Khin

    2009-05-01

    The Phu Lon skarn Cu-Au deposit is located in the northern Loei Fold Belt (LFB), Thailand. It is hosted by Devonian volcano-sedimentary sequences intercalated with limestone and marble units, intruded by diorite and quartz monzonite porphyries. Phu Lon is a calcic skarn with both endoskarn and exoskarn facies. In both skarn facies, andradite and diopside comprise the main prograde skarn minerals, whereas epidote, chlorite, tremolite, actinolite and calcite are the principal retrograde skarn minerals. Four types of fluid inclusions in garnet were distinguished: (1) liquid-rich inclusions; (2) daughter mineral-bearing inclusions; (3) salt-saturated inclusions; and (4) vapor-rich inclusions. Epidote contains only one type of fluid inclusion: liquid-rich inclusions. Fluid inclusions associated with garnet (prograde skarn stage) display high homogenization temperatures and moderate salinities (421.6-468.5 °C; 17.4-23.1 wt% NaCl equiv.). By contrast, fluid inclusions associated with epidote (retrograde skarn stage) record lower homogenization temperatures and salinities (350.9-399.8 °C; 0.5-8 wt% NaCl equiv.). These data suggest a possible mixing of saline magmatic fluids with external, dilute fluid sources (e.g., meteoric fluids), as the system cooled. Some fluid inclusions in garnet contain hematite daughters, suggesting an oxidizing magmatic environment. Sulfur isotope determinations on sulfide minerals from both the prograde and retrograde stages show a uniform and narrow range of δ34S values (-2.6 to -1.1 ‰ δ34S), suggesting that the ore-forming fluid contained sulfur of orthomagmatic origin. Overall, the Phu Lon deposit is interpreted as an oxidized Cu-Au skarn based on the mineralogy and fluid inclusion characteristics.

  16. Rapid assembly of structurally defined and highly functionalized conjugated dienes via tethered enyne metathesis.

    PubMed

    Yao, Q

    2001-06-28

    [reaction: see text] Conjugated dienes are versatile building blocks in organic synthesis, and the development of new methods for their synthesis remains an important topic in modern synthetic organic chemistry. We describe here an expedient synthesis of highly functionalized conjugated dienes through sequential silicon-tethered ring-closing enyne metathesis mediated by Grubbs' Ru carbene catalysts and Tamao oxidation. Notable attributes of this methodology include short synthetic manipulations and the structural complexity it confers on the resulting diene moiety. PMID:11418051

  17. An efficient, overall [4+1] cycloaddition of 1,3-dienes and nitrene precursors.

    PubMed

    Wu, Qiong; Hu, Jian; Ren, Xinfeng; Zhou, Jianrong

    2011-10-01

    Intermolecular cycloadditions of conjugated dienes and nitrene precursors usually produce aziridines. A generally useful method was lacking to directly provide the [4+1] cycloadducts, 3-pyrrolines. We have realized this transformation by using an uniquely active catalyst, copper(II) 1,1,1,5,5,5-hexafluoroacetylacetonate ([Cu(hfacac)(2)]). The method is applicable to a wide array of dienes with good yields. When 1,4-disubstituted dienes are used as substrates, good-to-excellent cis or trans selectivity can be obtained. Interestingly, the cis or trans preference depends on the nature of the substituents, rather than diene geometry. Mechanistic studies reveal that the [4+1] cycloaddition proceeds through diene aziridination and subsequent ring expansion. Among common copper catalysts, only [Cu(hfacac)(2)] can efficiently catalyze both steps, which explains the unique efficiency of the catalyst. PMID:21887836

  18. Synthesis, characterization, and reactivity of ruthenium diene/diamine complexes including catalytic hydrogenation of ketones.

    PubMed

    Morilla, M Esther; Rodríguez, Pilar; Belderrain, Tomas R; Graiff, Claudia; Tiripicchio, Antonio; Nicasio, M Carmen; Pérez, Pedro J

    2007-10-29

    Thermal reactions between [RuCl2(diene)]n (diene = 2,5-norbornadiene, nbd; 1,5-cyclooctadiene, cod) with an excess of N,N,N',N'-tetramethylethylene diamine (tmeda) afforded derivatives [RuCl2(diene)(tmeda)] (diene = nbd, 1; cod, 2) as a mixture of cis and trans isomers. When thermolysis was performed under H2 mixtures of hydride species [RuCl(H)(diene)(tmeda)] (diene = nbd, 3; cod, 4) and the bis-tmeda adduct trans-[RuCl2(tmeda)2] (5) were obtained in different ratios depending upon the reaction conditions and reaction times. Heating polymeric Ru(II) precursors in toluene in the presence of a 5-fold excess of the bulkier N,N,N',N'-tetraethylethylene diamine (teeda) resulted in a rare diamine dealkylation process with formation of trans-[RuCl2(nbd)(Et2NCH2CH2NHEt)] (6) and trans-[RuCl2(cod)(EtHNCH2CH2NHEt)] (7) in high yields. The presence of N-H functionalities in the coordinated diamine ligands of 6 and 7 was unambiguously established by single-crystal X-ray diffraction studies. The dealkylation process of the teeda ligand seems to proceed intramolecularly as shown by solution NMR studies performed with the soluble Ru(II) precursors trans-[RuCl2(amine)2(diene)] (diene = nbd, amine = morpholine, 9; diene = cod, amine = Et2NH, 10). The above complexes [RuCl2(diene)(diamine)] have been tested as precatalysts in the hydrogenation of ketones both for transfer as well as direct hydrogenation, the latter route being the most effective. PMID:17900107

  19. Recent Applications of Acyclic (Diene)iron Complexes and (Dienyl)iron Cations in Organic Synthesis

    PubMed Central

    Chaudhury, Subhabrata

    2009-01-01

    Complexation of (tricarbonyl)iron to an acyclic diene serves to protect the ligand against oxidation, reduction and cycloaddition reactions while the steric bulk of this adjunct serves to direct the approach reagents to unsaturated groups attached to the diene onto the face opposite to iron. Furthermore, the Fe(CO)3 moiety can serve to stabilize carbocation centers adjacent to the diene (i.e. pentadienyl-iron cations). Recent applications of these reactivities to the synthesis of polyene, cyclopropane, cycloheptadiene and cyclohexenone containing natural products or analogs will be presented. PMID:21709767

  20. Description of the tadpoles of two endemic frogs: the Phu Luang cascade frog Odorrana aureola (Anura: Ranidae) and the Isan big-headed frog Limnonectes isanensis (Anura: Dicroglossidae) from northeastern Thailand.

    PubMed

    Ampai, Natee; Rujirawan, Attapol; Arkajag, Jirachai; Mcleod, David S; Aowphol, Anchalee

    2015-01-01

    We describe the external morphology of the tadpoles of two frogs endemic to Thailand: the Phu Luang cascade frog    (Odorrana aureola) and the Isan big-headed frog (Limnonectes isanensis) from the type localities in the Phu Luang Wildlife Sanctuary, Loei Province, northeastern Thailand. Morphological and genetic characters (16S rRNA) were used to identify specimen and match tadpoles to the adults. Detailed descriptions of external morphology and coloration in life are provided for both species. We provide a brief discussion of the ecology of these tadpoles and a comparison to previously published data from tadpoles of closely related taxa. Additionally, we provide evidence for the utility of larval morphology in resolving the taxonomic puzzles presented by cryptic species complexes. PMID:26250010

  1. Substitution effect on the cylization/fluorination reaction of N-dienes in superacid.

    PubMed

    Vardelle, Emilie; Martin-Mingot, Agnès; Jouannetaud, Marie-Paule; Bachmann, Christian; Marrot, Jérôme; Thibaudeau, Sébastien

    2009-08-21

    The novel cyclization/fluorination reaction of N-dienes in superacid was extended to substituted substrates. The influence of the substitution on superelectrophilic character of dicationic intermediates was shown and its dramatic effect on the synthesis of fluoropiperidines was studied. On the basis of new dicationic alpha-chloronium ammonium intermediates, starting from halogen-substituted dienes, high-valued fluorinated piperidines were synthesized. PMID:19588903

  2. Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

    PubMed Central

    Röse, Philipp; Emge, Steffen; Yoshida, Jun-ichi

    2015-01-01

    Summary The cobalt(I)-catalysed 1,4-hydrovinylation reaction of allyloxytrimethylsilane and allyl alcohol with substituted 1,3-dienes leads to hydroxy-functionalised 1,4-dienes in excellent regio- and diastereoselective fashion. Those 1,4-dienols can be converted into tetrahydrofuran and pyran derivatives under indirect electrochemical conditions generating selenium or iodonium cations. The reactions proceed in good yields and regioselectivities for the formation of single diastereomers. PMID:25815067

  3. Spiro[2.4]hepta-4,6-dienes: synthesis and application in organic synthesis

    NASA Astrophysics Data System (ADS)

    Menchikov, L. G.; Nefedov, O. M.

    2016-03-01

    This review integrates and describes systematically the data in the field of spiro[2.4]hepta-4,6-dienes published in the past 15 years. The changes in the development of studies that took place during this period are noted. The methods for the synthesis, the reactivity details and key chemical transformations of spiro[2.4]hepta-4,6-dienes are considered, with the emphasis on applications of these compounds in organic synthesis. The bibliography includes 207 references.

  4. Non-Planar Structures of the High-Energy Rotational Conformers of 2-METHYLBUTA-1,3-DIENE (isoprene) and 2,3-DIMETHYLBUTA-1,3-DIENE

    NASA Astrophysics Data System (ADS)

    Panchenko, Yu. N.; Bock, Ch. W.; Larkin, J. D.; Abramenkov, A. V.; Kühnemann, F.

    2009-06-01

    Optimization of the geometrical parameters and determination of the force fields for rotamers of the title molecules were performed at the MP2(FC)/aug-cc-pVDZ//MP2(FC)/aug-cc-pVDZ computational level. The vibrational analyses of these conformers were carried out using scaled quantum-mechanical force field methodology. Recent experimental wavenumbers for these conformers and their deuteroisomers were incorporated into these analyses. The theoretical non-planar structures of the high-energy conformers of 2-methylbuta-1,3-diene (isoprene) and 2,3-dimethylbuta-1,3-diene were corroborated by good agreement between the experimental and theoretical wavenumbers of the molecules under investigation. The dihedral angles of the non-planar high-energy conformers for rotation around the =C-C= bond are as follows: 41.6^° for 2-methylbuta-1,3-diene (isoprene) and 47.0^° for 2,3-dimethylbuta-1,3-diene. Previous studies performed at the HF/6-31G level gave 41.0^° and 48.5^° for the first and second compounds, respectively. Yu. N. Panchenko, Ch. W. Bock, J. D. Larkin, A. V. Abramenkov, F. Kühnemann, Struct. Chem. 19, 421 (2008). Yu. N. Panchenko, Ch. W. Bock, J. D. Larkin, A. V. Abramenkov, Struct. Chem. 19, 793 (2008)

  5. Solvent-free cyclization of linear dienes using olefin metathesis and the Thorpe-Ingold effect

    SciTech Connect

    Forbees, M.D.E.; Myers, T.L.; Maynard, H.D.; Schulz, G.R. ); Patton, J.T.; Smith, D.W. Jr.; Wagener, K.B. )

    1992-12-30

    The olefin metathesis reaction is of great synthetic utility in polymer chemistry. The recent development of ring-opening (ROMP) and acyclic diene (ADMET) metathesis polymerization reactions has opened new avenues for the synthesis of novel polymeric materials. Recently the authors used ADMET to synthesize several photochemically active poly(keto olefins) using the catalyst Mo(CHCMe[sub 2]Ph)(NAr)(OCMe(CF[sub 3])[sub 2])[sub 2] (Ar = 2,6-diisopropylphenyl) (1) developed by Schrock and co-workers in 1990. In the course of that work, they discovered that neat samples of highly substituted dienes will cyclize quantitatively via metathesis to give difunctional five- and seven-membered rings instead of the expected linear polymer. Examples of substituted diene cyclizations by metathesis even in the presence of a solvent are rare. Their systematic exploitation in organic synthesis has therefore been limited to two recent studies by Fu and Grubbs, who cyclized several substituted diene ethers, amines, and amides to unsaturated oxygen and nitrogen heterocycles. Cyclization of unsubstituted dienes in various solvents has been reported, but complete conversion occurred in only a few cases. Formation of cyclic alkene oligomers from back-biting during the ROMP reaction is also known. The reactions reported here are unusual in that they are intermolecular between catalyst and substrate, yet can give 100% yield of product solely from the monomer in the absence of solvent. 13 refs.

  6. Anomalous Reactivity and Selectivity in the Intermolecular Diels-Alder Reactions of Multisubstituted Acyclic Dienes with Geometrical Isomers of Enals.

    PubMed

    Zhou, Jia-Hui; Cai, Sai-Hu; Xu, Yun-He; Loh, Teck-Peng

    2016-05-20

    A Lewis-acid catalyzed intermolecular Diels-Alder reaction between multisubstituted acyclic dienes and the E and Z isomers of α,β-enals was studied. It was found that the diene reacted selectively with the Z-isomer of the α,β-enal. PMID:27132468

  7. Reversal of the Regiochemistry in the Rhodium-Catalyzed [4+3] Cycloaddition Between Vinyldiazoacetates and Dienes

    PubMed Central

    Guzmán, Pablo E.; Lian, Yajing

    2015-01-01

    A regio-, diastereo- and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst Rh2(S-BTPCP)4. This methodology provides facile access to 1,4-cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of vinylcarbenes with dienes. PMID:25266984

  8. Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

    PubMed Central

    Eberlin, Ludovic; Tripoteau, Fabien; Carreaux, François

    2014-01-01

    Summary In the last few years, multicomponent reactions involving boron substituted 1,3-dienes have emerged as important tools in synthetic organic chemistry. The most significant recent results and developments obtained in this area are reported in this review. PMID:24605143

  9. The stereoselective synthesis of dienes through dehalogenative homocoupling of terminal alkenyl bromides on Cu(110).

    PubMed

    Sun, Qiang; Cai, Liangliang; Ma, Honghong; Yuan, Chunxue; Xu, Wei

    2016-05-21

    We have successfully achieved the stereoselective synthesis of a specific cis-diene moiety through a dehalogenative homocoupling of alkenyl bromides on the Cu(110) surface, where the formation of a cis-form organometallic intermediate is the key to such a stereoselectivity as determined by DFT calculations. PMID:27063567

  10. Implicit Learning of Nonlocal Musical Rules: A Comment on Kuhn and Dienes (2005)

    ERIC Educational Resources Information Center

    Desmet, Charlotte; Poulin-Charronnat, Benedicte; Lalitte, Philippe; Perruchet, Pierre

    2009-01-01

    In a recent study, G. Kuhn and Z. Dienes (2005) reported that participants previously exposed to a set of musical tunes generated by a biconditional grammar subsequently preferred new tunes that respected the grammar over new ungrammatical tunes. Because the study and test tunes did not share any chunks of adjacent intervals, this result may be…

  11. A New Steroidal 5,7-Diene Derivative, 3β-Hydroxyandrosta-5, 7-Diene-17β-Carboxylic Acid, Shows Potent Anti-proliferative Activity

    PubMed Central

    Kim, Tae-Kang; Chen, Jianjun; Li, Wei; Zjawiony, Jordan; Miller, Duane; Janjetovic, Zorica; Tuckey, Robert C; Slominski, Andrzej

    2010-01-01

    The new steroidal 5,7-diene, 3β-hydroxyandrosta-5,7-diene-17β-carboxylic acid (17-COOH-7DA), was synthesized from 21-acetoxypregnenolone, with the oxidative cleavage of the side chain being dependent on the presence of oxygen. In human epidermal (HaCaT) keratinocytes, 17-COOH-7DA inhibited proliferation in a dose-dependent manner, starting at a dose as low as 10−11 M. This inhibition was accompanied by decreased expression of epidermal growth factor receptor, bcl2 and cyclin E2 mRNAs and by increased expression of involucrin mRNA. Inhibition of proliferation was associated with slowing of the cell cycle in G1/G0 phases but not with cell death. 17-COOH-7DA was significantly more potent than pregnenolone, 17-COOH-pregnenolone, 17-COOCH3-7DA and calcitriol. 17-COOH-7DA also inhibited proliferation of normal human epidermal melanocytes and human and hamster melanoma lines, however, with lower potency than for keratinocytes. In normal human dermal fibroblasts 17-COOH-7DA stimulated proliferation in serum-free media but inhibited it in the presence of 5% serum. 17-COOH-7DA inhibited cell colony formation of human and hamster melanoma cells, and induced monocyte-like differentiation of human HL60 leukemia cells. Thus, the new steroidal 5,7-diene, 17-COOH-7DA, can serve as an inhibitor of proliferation of normal keratinocytes and normal and malignant melanocytes, as a condition-dependent regulator of fibroblast proliferation and a stimulator of leukemia cell differentiation. PMID:20025893

  12. "On Water" Organocatalyzed [4 + 2] Cycloaddition of Enones and Nitro Dienes for the Enantioselective Synthesis of Densely Substituted Cyclohexanones.

    PubMed

    Vamisetti, Ganga B; Chowdhury, Raghunath; Kumar, Mukesh; Ghosh, Sunil K

    2016-05-01

    An "on water" hydroquinine-based primary amine-benzoic acid organocatalyst system was found to be best suited to produce 3,4,5-trisubstituted cyclohexanones with a nitro group in the 4-position from enones and nitro dienes under ambient conditions in good yield, with good diastereoselectivity, and with excellent enantioselectivity. An appreciable rate enhancement by water was observed compared to organic solvents. Mechanistic analysis of the reaction suggests that it followed an endo [4 + 2] cycloaddition with enamine of enone as diene and nitro diene as dienophile. PMID:27120404

  13. Effects of diene valepotriates from Valeriana glechomifolia on Na+/K+-ATPase activity in the cortex and hippocampus of mice.

    PubMed

    Müller, Liz G; Salles, Luisa; Lins, Helena A; Feijó, Priscilla R O; Cassel, Eduardo; Vargas, Rubem; von Poser, Gilsane L; Noël, François; Quintas, Luis E M; Rates, Stela M K

    2015-02-01

    Diene valepotriates obtained from Valeriana glechomifolia present antidepressant-like activity, mediated by dopaminergic and noradrenergic neurotransmissions. Also, previous studies have shown inhibitory activity of diene valepotriates towards Na(+)/K(+)-ATPase from the rat brain in vitro. Nevertheless, in vivo studies regarding the action of diene valepotriates on this enzyme are still lacking. Considering that Na(+)/K(+)-ATPase cerebral activity is involved in depressive disorders, the aim of this study was to investigate the effects of acute (5 mg/kg, p. o.) and repeated (5 mg/kg, p. o., once a day for three days) diene valepotriate administration on Na(+)/K(+)-ATPase activity in the cortex and hippocampus of mice submitted or not submitted to the forced swimming test. In addition, the protein expression of Na(+)/K(+)-ATPase α1, α2, and α3 isoforms in the cortex of mice repeatedly treated with diene valepotriates (and submitted or not submitted to the forced swimming test) was investigated. Diene valepotriates significantly decreased mice immobility time in the forced swimming test when compared to the control group. Only the animals repeatedly treated with diene valepotriates presented increased Na(+)/K(+)-ATPase activity in the cerebral cortex, and the exposure to the forced swimming test counteracted the effects of the diene valepotriates. No alterations in the hippocampal Na(+)/K(+)-ATPase activity were observed. Repeated diene valepotriate administration increased the cortical content of the α2 isoform, but the α3 isoform protein expression was augmented only in mice repeatedly treated with diene valepotriates and forced to swim. Mice treated with the vehicle and submitted to the forced swimming test also presented an increase in the content of the α2 isoform, but no alterations in Na(+)/K(+)-ATPase activity. These results suggest that cortical Na(+)/K(+)-ATPase may represent a molecular target of the diene valepotriates in vivo and long

  14. Regio- and Stereoselective Monoepoxidation of Dienes using Methyltrioxorhenium: Synthesis of Allylic Epoxides

    PubMed Central

    2015-01-01

    Methyltrioxorhenium (MTO) complexed with pyridine was shown to be a highly effective catalyst for the regioselective monoepoxidation of conjugated di- and trienes using 30% H2O2 at or below room temperature. The resultant allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well as substructures present in many bioactive natural products. The site of epoxidation was dependent upon olefin substitution, olefin geometry (Z vs E), and the presence of electron-withdrawing substituents on adjacent carbons. For 1-acyl(silyl)oxypenta-2,4-dienes, epoxidation of the distal olefin was generally favored in contrast to the adjacent regioselectivity characteristic of Sharpless, peracid, and other directed epoxidations of hydroxylated dienes. PMID:25321319

  15. Lewis acid activation of carbodicarbene catalysts for Rh-catalyzed hydroarylation of dienes.

    PubMed

    Roberts, Courtney C; Matías, Desirée M; Goldfogel, Matthew J; Meek, Simon J

    2015-05-27

    The activation of carbodicarbene (CDC)-Rh(I) pincer complexes by secondary binding of metal salts is reported for the catalytic site-selective hydro-heteroarylation of dienes (up to 98% yield and >98:2 γ:α). Reactions are promoted by 5 mol % of a readily available tridentate (CDC)-Rh complex in the presence of an inexpensive lithium salt. The reaction is compatible with a variety of terminal and internal dienes and tolerant of ester, alkyl halide, and boronate ester functional groups. X-ray data and mechanistic experiments provide support for the role of the metal salts on catalyst activation and shed light on the reaction mechanism. The increased efficiency (120 to 22 °C) made available by catalytic amounts of metal salts to catalysts containing C(0) donors is a significant aspect of the disclosed studies. PMID:25961506

  16. Formal Asymmetric (4+1) Annulation Reaction between Sulfur Ylides and 1,3-Dienes.

    PubMed

    Rousseau, Olivier; Delaunay, Thierry; Dequirez, Geoffroy; Trieu-Van, Tran; Robeyns, Koen; Robiette, Raphaël

    2015-09-01

    A highly enantioselective synthesis of functionalized cyclopentanoids by a formal asymmetric (4+1) annulation strategy was developed. The methodology consists of a stereoselective cyclopropanation reaction between chiral sulfur ylides and 1,3-dienes followed by a, in situ, stereospecific MgI2 -catalyzed rearrangement of vinylcyclopropanes. This method is distinguished by a remarkable compatibility with functional groups and a high stereocontrol. PMID:26235566

  17. Asymmetric Conjugate Alkynylation of Cyclic α,β-Unsaturated Carbonyl Compounds with a Chiral Diene Rhodium Catalyst.

    PubMed

    Dou, Xiaowei; Huang, Yinhua; Hayashi, Tamio

    2016-01-18

    Asymmetric conjugate alkynylation of cyclic α,β-unsaturated carbonyl compounds (ketones, esters, and amides) was realized by use of diphenyl[(triisopropylsilyl)ethynyl]methanol as an alkynylating reagent in the presence of a rhodium catalyst coordinated with a new chiral diene ligand (Fc-bod; bod=bicyclo[2.2.2]octa-2,5-diene, Fc=ferrocenyl) to give high yields of the corresponding β-alkynyl-substituted carbonyl compounds with 95-98% ee. PMID:26636764

  18. Comment on: Discovery of the fossiliferous Cu Brei Formation (Lower Devonian) in the Kon Tum Block (South Viet Nam): Tong-Dzuy Thanh, Than Duc Duyen, Nguyen Huu Hung, Bui Phu My

    NASA Astrophysics Data System (ADS)

    Maluski, Henri

    2008-01-01

    The publication of Tong-Dzuy Thanh et al. calls for two remarks: The metamorphism in the "Kon Tum block" cannot be younger than Permian because the outcrop they describe is not metamorphic. Their very interesting discovery is a new piece of evidence for the exotic origin of the Dien Binh Series.

  19. Polymerization of 1,3-Conjugated Dienes with Rare-Earth Metal Precursors

    NASA Astrophysics Data System (ADS)

    Zhang, Zhichao; Cui, Dongmei; Wang, Baoli; Liu, Bo; Yang, Yi

    This chapter surveys the publications except patents related to cis-1,4-, trans-1,4-, 3,4-regio-, and stereoselective polymerizations of 1,3-conjugated dienes with rare-earth metal-based catalytic systems during the past decade from 1999 to 2009. The concerned catalyst systems are classified into the conventional Ziegler-Natta catalysts, the modified Ziegler-Natta catalysts, and the single-site cationic systems composed of lanthanocene and noncyclopentadienyl precursors, respectively. For the conventional Ziegler-Natta catalysts of the most promising industry applicable recipe, the multicomponents based on lanthanide carboxylate or phosphate or alkoxide precursors, research works concern mainly about optimizing the catalyst preparation and polymerization techniques. Special emphases are put on the factors that influence the catalyst homogeneority, catalytic activity and efficiency, as well as cis-1,4-selectivity. Meanwhile, tailor-made lanthanide aryloxide and amide complexes are designed and fully characterized to mimic the conventional Ziegler-Natta catalysts, anticipated to elucidate the key processes, alkylation and cationization, for generating the active species. Regarding to the single-site catalytic systems generally comprising well-defined complexes containing lanthanide-carbon bonds, investigations cover their versatile catalytic activity and efficiency, and the distinguished regio- and stereoselectivity for both polymerization of dienes and copolymerization of dienes with alkenes. The correlation between the sterics and electronics of ligands and the molecular structures of the complexes and their catalytic performances are highlighted. The isolation of the probable active species in these polymerization processes from the stoichiometric reactions of the precursors with activators will be presented.

  20. Stereoselective Rh-Catalyzed Hydrogenative Desymmetrization of Achiral Substituted 1,4-Dienes.

    PubMed

    Fernández-Pérez, Héctor; Lao, Joan R; Vidal-Ferran, Anton

    2016-06-17

    Highly efficient catalytic stereoselective hydrogenative desymmetrization reactions mediated by rhodium complexes derived from enantiopure phosphine-phosphite (P-OP) ligands are described. The highest performing ligand, which contains a TADDOL-derived phosphite fragment [TADDOL = (2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(diphenylmethanol)], presented excellent catalytic properties for the desymmetrization of a set of achiral 1,4-dienes, providing access to the selective formation of a variety of enantioenriched secondary and tertiary alcohols (six examples, up to 92% ee). PMID:27230728

  1. C-H Polyaddition of Dimethoxyarenes to Unconjugated Dienes by Rare Earth Catalysts.

    PubMed

    Shi, Xiaochao; Nishiura, Masayoshi; Hou, Zhaomin

    2016-05-18

    The C-H polyaddition of dimethoxyarenes such as 1,4-dimethoxybenzene and 4,4'-dimethoxybiphenyl to unconjugated dienes such as norbornadiene and 1,4-divinylbenzene has been achieved for the first time by using cationic half-sandwich rare earth alkyl catalysts. This protocol afforded novel polymer materials consisting of dimethoxyarene moieties and nonpolar hydrocarbon structure motifs (cyclic, linear, and aromatic) in perfectly alternating sequences that are otherwise difficult to make. The reaction proceeded via C═C double bond insertion into a C-H bond ortho to each of the two methoxy groups in a step-growth polymerization fashion. PMID:27149275

  2. Food as a source of dioxin exposure in the residents of Bien Hoa City, Vietnam.

    PubMed

    Schecter, Arnold; Quynh, Hoang Trong; Pavuk, Marian; Päpke, Olaf; Malisch, Rainer; Constable, John D

    2003-08-01

    Recently, elevated dioxin levels, over 5 parts per trillion (ppt) 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), from Agent Orange was reported in 95% of 43 selected residents of Bien Hoa City, a city in southern Vietnam near a former air base used for Agent Orange-spraying missions. Agent Orange herbicide, contaminated with TCDD, was sprayed in Vietnam between 1962 and 1971 primarily for use as a defoliant. Typical blood TCCD levels are 2 ppt in Vietnamese, but levels are as high as 413 ppt in Bien Hoa City. Elevated TCDD was found in children born many years after Agent Orange spraying ended and in immigrants from non-Agent Orange-sprayed parts of Vietnam, which documented new exposures. Extremely elevated soil TCDD samples, over 1 million ppt, and elevated TCDD in sediment were found in some nearby areas such as Bien Hung Lake. The primary route of intake of almost all dioxins in humans is food. However, in our prior studies in Bien Hoa, food was unavailable for dioxin analysis so the route of intake was not confirmed. In the 1970s, while Agent Orange was still being sprayed, elevated human milk TCDD levels as high as 1850 were detected in milk from Vietnamese people living in Agent Orange-sprayed areas where consumption of fish was high. Furthermore, also in the 1970s, elevated TCDD levels (up to 810 ppt) were found in fish and shrimp from the same area as the milk donors. In the 1980s, we found elevated TCDD and also other organohalogen levels in human tissue, pork, fish, a turtle, and a snake in Southern Vietnam. For these reasons, we recently collected food from Bien Hoa and analyzed it for dioxins, polychlorinated biphenyls (PCBs), DDT and its metabolites, and other organochlorines. We found marked elevation of TCDD, the dioxin characteristic of Agent Orange, in some of the food products, including ducks with 276 ppt and 331 ppt wet weight, chickens from 0.031-15 ppt wet weight, fish from 0.063-65 ppt wet weight, and a toad with 56 ppt wet weight. Usual TCDD

  3. Unprecedented Intramolecular [4 + 2]-Cycloaddition between a 1,3-Diene and a Diazo Ester.

    PubMed

    Qiu, Huang; Srinivas, Harathi D; Zavalij, Peter Y; Doyle, Michael P

    2016-02-17

    Diazo compounds that are well-known to undergo [3 + 2]-cycloaddition provide the first examples of the previously unknown [4 + 2]-cycloaddition with dienes that occur thermally under mild conditions and in high yields. Reactions are initiated from reactants prepared from propargyl aryldiazoacetates that undergo gold(I)-catalyzed rearrangement to activated 1,3-dienyl aryldiazoacetates. These reactions proceed to mixtures of both [4 + 2]-cycloaddition and the 1,3-dienyl aryldiazoacetate after long reaction times. At short reaction times, however, both E- and Z-1,3-dienyl aryldiazoacetates are formed and, after isolation, thermal reactions with the E-isomers form the products from [4 + 2]-cycloaddition with ΔH(‡)298 = 15.6 kcal/mol and ΔS(‡)298 = -27.3 cal/(mol·°C). The Z-isomer is inert to [4 + 2]-cycloaddition under these conditions. The Hammett relationships from aryl-substituted diazo esters (ρ = +0.89) and aryl-substituted dienes (ρ = -1.65) are consistent with the dipolar nature of this transformation. PMID:26794409

  4. Ligand-based reactivity of a platinum bisdithiolene: double diene addition yields a new C2-chiral chelate ligand.

    PubMed

    Kerr, Mitchell J; Harrison, Daniel J; Lough, Alan J; Fekl, Ulrich

    2009-10-01

    The reaction of Pt(tfd)(2) [tfd = S(2)C(2)(CF(3))(2)] with excess 2,3-dimethyl-1,3-butadiene initially yields the expected 1:1 adduct, in which the diene has added across two sulfur atoms on separate tfd ligands. However, within 1 day at 50 degrees C, this kinetic product quantitatively converts into a thermodynamic product where two dienes have added to one tfd ligand via unprecedented addition across the dithiolene CS bonds. The new reaction is highly selective for the C(2)-symmetric diastereomer. A new chiral bisthioether chelate ligand has formed in the product, which has been characterized crystallographically. PMID:19634863

  5. Nitroso Diels-Alder (NDA) Reaction as an Efficient Tool for the Functionalization of Diene-Containing Natural Products

    PubMed Central

    Carosso, Serena; Miller, Marvin J.

    2014-01-01

    This review describes the use of nitroso Diels-Alder reactions for the functionalization of complex diene-containing natural products in order to generate libraries of compounds with potential biological activity. The application of this methodology to the structural modification of a series of natural products (thebaine, steroidal dienes, rapamycin, leucomycin, colchicine, isocolchicine and piperine) is discussed using relevant examples from the literature from 1973 onwards. The biological activity of the resulting compounds is also discussed. Additional comments are provided that evaluate the methodology as a useful tool in organic, bioorganic and medicinal chemistry. PMID:25119424

  6. Successive C-C Coupling of Dienes to Vicinally Dioxygenated Hydrocarbons: Ruthenium Catalyzed [4+2] Cycloaddition across the Diol, Hydroxycarbonyl or Dione Oxidation Levels

    PubMed Central

    Geary, Laina M.; Glasspoole, Ben W.; Kim, Mary M.; Krische, Michael J.

    2013-01-01

    The ruthenium(0) catalyst generated from Ru3(CO)12 and tricyclohexylphosphine or BIPHEP promotes successive C-C coupling of dienes to vicinally dioxygenated hydrocarbons across the diol, hydroxyketone and dione oxidation levels to form products of [4+2] cycloaddition. A mechanism involving diene-carbonyl oxidative coupling followed by intramolecular carbonyl addition from the resulting allylruthenium intermediate is postulated. PMID:23448269

  7. Strategic use of nickel(0)-catalyzed enyne-epoxide reductive coupling towards the synthesis of (−)-cyatha-3,12-diene

    PubMed Central

    Sparling, Brian A.; Simpson, Graham L.; Jamison, Timothy F.

    2009-01-01

    Various situations are explored in which the nickel(0)-catalyzed enyne-epoxide reductive coupling was utilized to access key intermediates towards the total synthesis of (−)-cyatha-3,12-diene (1). Enantioenriched 3,5-dien-1-ols with a variety of functionality were obtained in a straightforward manner from easily accessible 1,3-enynes and terminal epoxides. PMID:20161213

  8. Mechanistic Aspects of the Palladium-Catalyzed Isomerization of Allenic Sulfones to 1-Arylsulfonyl 1,3-Dienes.

    PubMed

    Hampton, Carissa S; Harmata, Michael

    2016-06-01

    When an allenic sulfone is treated under palladium catalysis in the presence of a weak acid, isomerization to a 1-arylsulfonyl 1,3-diene occurs. Investigations of the mechanistic aspects of this isomerization were performed, leading to the mechanism proposed herein. Some further studies of reaction parameters are reported. PMID:27127922

  9. Novel polymer composites from waste ethylene-propylene-diene-monomer rubber by supercritical CO2 foaming technology.

    PubMed

    Jeong, Keuk Min; Hong, Yeo Joo; Saha, Prosenjit; Park, Seong Ho; Kim, Jin Kuk

    2014-11-01

    In this study, a composite has been prepared by mixing waste rubber, such as ethylene-propylene-diene-monomer and low-density poly ethylene foaming, with supercritical carbon dioxide. In order to optimise the foaming process of the waste ethylene-propylene-diene-monomer-low-density poly ethylene composite, the variations of pressure and temperature on the foamed Microcell formation were studied. As indicated in scanning electron microscope photographs, the most uniform microcellular pattern was found at 200 bar and 100 °C using 30% by weight of waste ethylene-propylene-diene-monomer. Carbon dioxide could not be dissolved uniformly during foaming owing to extensive cross-linking of the waste ethylene-propylene-diene-monomer used for the composite. As a result the presence of un-uniform microcells after foaming were observed in the composite matrix to impart inferior mechanical properties of the composite. This problem was solved with uniform foaming by increasing the cross-link density of low-density poly ethylene using 1.5 parts per hundred dicumyl peroxide that enhances composite tensile and compressive strength up to 57% and 15%, respectively. The composite has the potential to be used as a foaming mat for artificial turf. PMID:25106537

  10. Determination of double bond position in conjugated dienes by chemical ionization mass spectrometry with isobutane

    SciTech Connect

    Doolittle, R.E.; Tumlinson, J.H.; Proveaux, A.

    1985-07-01

    The chemical ionization (CI) mass spectra of a series of functionalized conjugated dienes, including aldehydes, alcohols, formates, acetates, and hydrocarbons were investigated to determine whether fragmentations occur that are characteristic of the position of the conjugated system within the hydrocarbon chain. CI with isobutane as ionizing gas produces structure-specific fragment ions with m/z ratios that can be used to locate the positions of the double bonds in most of the cases studied. When the conjugated system is proximal to the functional group or conjugated with the functional group, other fragmentation processes take precedence. These patterns of fragmentations constitute a very useful analytical tool for the location of conjugated double bonds in a variety of natural products. 34 references, 3 tables, 3 figures.

  11. 3α-Hy­droxy­tirucalla-8,24-dien-21-oic acid

    PubMed Central

    Yousuf, S.; Kamdem, R. S. T.; Ngadjui, B. T.; Wafo, P.; Fun, Hoong-Kun

    2011-01-01

    The title compound, C30H48O3, a triterpene isolated from the resin of canarium schweinfurthiiand, is an isomer of the previously reported triterpene 3α-hy­droxy­tirucalla-7,24-dien-21-oic acid [Mora et al. (2001 ▶). Acta Cryst. C57, 638–640], which crystallizes in the same trigonal space group. The title mol­ecule consists of four fused rings having chair, half-chair, half-chair and envelope conformations for rings A, B, C and D, respectively (steroid labelling). An intra­molecular C—H⋯O hydrogen bond generates an S(7) ring. In the crystal, mol­ecules are linked by O—H⋯O and C—H⋯O inter­actions, forming (001) sheets. PMID:21754206

  12. Total (1)H NMR assignment of 3β-acetoxypregna-5,16-dien-20-one.

    PubMed

    Becerra-Martinez, Elvia; Ramírez-Gualito, Karla E; Pérez-Hernández, Nury; Joseph-Nathan, Pedro

    2015-12-01

    This work describes the total and unambiguous assignment of the 750 MHz (1)H NMR spectrum of 3β-acetoxypregna-5,16-dien-20-one or 16-DPA (1), the well-known intermediate utilized in the synthesis of biological important commercial steroids. The task was accomplished by extracting the coupling constant values in the overlapped spectrum region by HSQC, and using these values in the (1)H iterative full spin analysis integrated in the PERCH NMR software. Comparison of the experimental vicinal coupling constants of 1 with the values calculated using Altona provides an excellent correlation. The same procedure, when applied to the published data of progesterone (2) and testosterone (3), afforded an acceptable correlation for 2 and a poor correlation for 3. In the last case, this suggested the reassignment of all four vicinal coupling constants for the methylene signals at the C-15 and C-16 positions, demonstrating the utility of this methodology. PMID:26476187

  13. The diene isomerization energies dataset: A difficult test for double-hybrid density functionals?

    NASA Astrophysics Data System (ADS)

    Wykes, M.; Pérez-Jiménez, A. J.; Adamo, C.; Sancho-García, J. C.

    2015-06-01

    We have systematically analyzed the performance of some representative double-hybrid density functionals (including PBE0-DH, PBE-QIDH, PBE0-2, XYG3, XYGJ-OS, and xDH-PBE0) for a recently introduced database of diene isomerization energies. Double-hybrid models outperform their corresponding hybrid forms (for example, PBE0-DH, PBE0-2, and PBE-QIDH are more accurate than PBE0) and the XYG3, XYGJ-OS, and xDH-PBE0 functionals perform excellently, providing root mean square deviation values within "calibration accuracy." XYGJ-OS and xDH-PBE0 also rival the best performing post-Hartree-Fock methods at a substantially lower cost.

  14. Public health assessment of dioxin-contaminated fish at former US airbase, Bien Hoa, Vietnam.

    PubMed

    Durant, James T; Boivin, Thomas G; Pohl, Hana R; Sinks, Thomas H

    2015-01-01

    Ponds at the former US airbase at Ben Hoa, Vietnam are contaminated with Agent Orange. The ponds had been used for aquaculture, and in all likelihood, fish from those ponds have been sold to the public. We assessed human exposure to 2,3,7,8-tetrachloro-dibenzo-dioxin (2,3,7,8-TCDD) in fish samples from the ponds. For on-base tilapia, muscle concentrations 2,3,7,8-TCDD ranged from 1.4 to 32.7 pg/g. Fat concentrations ranged from 73.3 to 3990 pg/g. Estimated human exposure doses exceed international guidelines and exceed 2,3,7,8-TCDD's lowest adverse effect levels. The Bien Hoa fishponds are a completed human pathway for TCDD exposure. PMID:25087452

  15. Vertical distribution of dioxins in soil of Bien Hoa airbase, Vietnam.

    PubMed

    Huyen, Dang Thuong; Igarashi, Toshifumi; Shiraiwa, Takuya

    2015-01-01

    Bien Hoa airbase is a known dioxin-contaminated hotspot in Vietnam. The contamination occurred during the Vietnam War at the site where dioxins were transported, stored, sprayed, and spilled in the area. Dioxins, which are cancer inducing substances, may transfer from the soil to food crops and finally to human beings living around the area. Many surveys of dioxins in soil, water, organisms, and human have been carried out in this study area since 2002. In this paper vertical distribution of dioxins in undisturbed soil cores were examined. Twelve soil samples from three drilled cores were collected to analyze dioxin levels according to the standard Japanese analytical method. The results showed that the toxicity equivalency quantity (TEQ) in one soil sample at a depth of 2.6 m reached 3,300 pg-TEQ/g-dw. High TEQs were also observed in the clay layer. This anomaly of dioxin concentrations could be attributed to the affinity of dioxins for the clay layer. The isomer patterns in the soils were different from those in the soil of Hokkaido in that 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) was the most dominant in the soil sample. This indicates that the dioxins originate from a defoliant Agent Orange disposed at the site after the Vietnam War. PMID:26155439

  16. Total Synthesis of the Galbulimima Alkaloids Himandravine and GB17 Using Biomimetic Diels–Alder Reactions of Double Diene Precursors

    PubMed Central

    Larson, Reed T.; Pemberton, Ryan P.; Franke, Jenna M.; Tantillo, Dean J.; Thomson, Regan J.

    2015-01-01

    The enantioselective total syntheses of himandravine and GB17 were completed through a common biomimetic strategy involving Diels–Alder reactions of unusual double diene containing linear precursors. The double diene precursors, containing or lacking a C12 substituent as required to produce GB17 or himandravine, respectively, were found to undergo Diels–Alder reactions to afford mixtures of regioisomeric cycloadducts that map onto the alternative carbocyclic frameworks of both himandravine and GB17. Computational investigations revealed that these Diels–Alder reactions proceed via transition state structures of similar energy that have a high degree of bispericyclic character and that the low levels of regioselectivity observed in the reactions are a consequence of competing orbital interaction and distortion energies. The combined experimental and computational results provide valuable insights into the biosynthesis of the Galbulimima alkaloids. PMID:26305231

  17. Synthesis of 1,3-Dienes via a Sequential Suzuki-Miyaura Coupling/Palladium-Mediated Allene Isomerization Sequence.

    PubMed

    Al-Jawaheri, Yassir; Kimber, Marc C

    2016-07-15

    We report a facile method for the synthesis of 1,3-dienes by a sequential process consisting of a palladium-catalyzed, base-free, Suzuki-Miyaura coupling/isomerization sequence. This sequence couples boronic acids with propargyl alcohols, generating the requisite allene in situ, followed by conversion of the unactivated allene to its 1,3-diene via a hydro-palladation/dehydro-palladation process. This process is general for a range of boronic acids, including boronic acids with electron-donating and -withdrawing groups, as well as heteroarylboronic acids. Key to this process is the boric acid byproduct of the base-free Suzuki-Miyauru coupling, which generates the required palladium-hydrido complex [H-Pd(II)-OB(OH)2] required for the isomerization. PMID:27355240

  18. Total Synthesis of the Galbulimima Alkaloids Himandravine and GB17 Using Biomimetic Diels-Alder Reactions of Double Diene Precursors.

    PubMed

    Larson, Reed T; Pemberton, Ryan P; Franke, Jenna M; Tantillo, Dean J; Thomson, Regan J

    2015-09-01

    The enantioselective total syntheses of himandravine and GB17 were completed through a common biomimetic strategy involving Diels-Alder reactions of unusual double diene containing linear precursors. The double diene precursors, containing or lacking a C12 substituent as required to produce GB17 or himandravine, respectively, were found to undergo Diels-Alder reactions to afford mixtures of regioisomeric cycloadducts that map onto the alternative carbocyclic frameworks of both himandravine and GB17. Computational investigations revealed that these Diels-Alder reactions proceed via transition state structures of similar energy that have a high degree of bispericyclic character and that the low levels of regioselectivity observed in the reactions are a consequence of competing orbital interaction and distortion energies. The combined experimental and computational results provide valuable insights into the biosynthesis of the Galbulimima alkaloids. PMID:26305231

  19. Ruthenium-catalyzed intramolecular metathesis of dienes and its application in the synthesis of bridged and spiro azabicycles

    NASA Astrophysics Data System (ADS)

    Kuznetsov, N. Yu; Bubnov, Yu N.

    2015-07-01

    The review presents a historical excursion into catalytic alkene metathesis, covering the problems of history of the discovery of this process, as well as investigations on the properties, structure and reactivity of the most popular ruthenium catalysts for metathesis, mechanism of their action and decomposition. The main part covers studies devoted to the syntheses of bridged azabicyclic and 1-azaspirocyclic compounds comprising the intramolecular metathesis of dienes as the key step. The formation of a bicyclic skeleton of a series of natural bridged (cocaine, ferruginine, calystegines, and anatoxin-a) and spiro (pinnaic acids, halichlorine, hystrionicotoxin, and cephalotaxine) azabicycles, as well as their analogues and compounds with larger rings is demonstrated. The methods for the synthesis of diene precursors and the conditions for final assembling of the bicyclic compounds are considered in detail. The generalization of the literature data allows one to efficiently carry out the mentioned process taking into account the most important features. The bibliography includes 129 references.

  20. [Preparation of androsta-1,4-diene-3,17-dione from sterols using Mycobacterium neoaurum VKPM As-1656 strain].

    PubMed

    Molchanova, M A; Andriushina, V A; Savinova, T S; Stytsenko, T S; Rodina, N V; Voĭshvillo, N E

    2007-01-01

    A product of microbiological cleavage of the sterols side chain, androsta-1,4-diene-3,17-dione, is toxic for bacteria, in particular, actinobacteria of the genera Mycobacterium and Arthrobacter. Sterols were transformed into androsta-1,4-diene-3,17-dione by culturing the M. neoaurum VKPM An-1656 strain in a high yield, provided that a sorbent was used for elimination of contact between the bacterial cells and the product. Unlike the cholesterol side chain, the more branched chains of phytosterols were cleaved in the presence of M. neoaurum at a high rate only under turbulent stirring of the culture medium, which intensified the formation of hydrocarbonate ion from NaNI3 in situ. PMID:17682396

  1. Enantioselective Aminomethylamination of Conjugated Dienes with Aminals Enabled by Chiral Palladium Complex-Catalyzed C-N Bond Activation.

    PubMed

    Liu, Yang; Xie, Yinjun; Wang, Hongli; Huang, Hanmin

    2016-04-01

    A novel highly enantioselective aminomethylamination of conjugated dienes with aminals catalyzed by a chiral palladium complex ligated with BINOL-derived chiral diphosphinite has been successfully developed. This reaction proceeds via a Pd-catalyzed cascade C-N bond activation, aminomethylation, and asymmetric allylic amination reaction under mild reaction conditions, providing a unique and efficient strategy for the synthesis of enantiomerically pure allylic 1,3-diamines. PMID:26998813

  2. The true identity of the triterpene component of Wyethia mollis, a lanosta-diene containing a tetrahydropyran E-ring.

    PubMed

    Smith, Cole T; Noll, Bruice; Waddell, Thomas G; Knight, Kyle S

    2013-03-01

    The crystal structure of a triterpene component of Wyethia mollis has been obtained and compared with the previously reported structure of the compound. The compound in the crystal structure, lanosta-8,24-dien-3-one, 16,23-epoxy-(161beta, 23R), (1), is different from the previously reported compound, but has identical NMR and mass spectrometric data. The revised structure contains a tetrahydropyran E ring, a structural moiety rare in steroid triterpenes. PMID:23678796

  3. Ionizing radiation-induced destruction of benzene and dienes in aqueous media.

    PubMed

    Al-Sheikhly, Mohamad; Poster, Dianne L; An, Jung-Chul; Neta, Pedatsur; Silverman, Joseph; Huie, Robert E

    2006-05-01

    Pulse radiolysis with spectrophotometric and conductometric detection was utilized to study the formation and reactions of radicals from benzene and dienes in aqueous solutions. The benzene OH adduct, *C6H6OH, reacts with O2 (k = 3 x 10(8) L mol(-1) s(-1)) in a reversible reaction. The peroxyl radical, HOC6H6O2*, undergoes O2*- elimination, bimolecular decay, and reaction with benzene to initiate a chain reaction, depending on the dose rate, benzene concentration, and pH. The occurrence of the chain reaction is demonstrated in low-dose-rate gamma radiolysis experiments where the consumption of O2 was monitored. 1,4-Cyclohexadiene, 1,4-hexadiene, and 1,4-pentadiene form OH-adducts and undergo H-abstraction by O*- radicals. The OH-adducts react with O2 to form peroxyl radicals. These peroxyl radicals, however, do not undergo unimolecular O2*- elimination but rather decay by second-order processes, which lead to subsequent steps of O2*- elimination. PMID:16719115

  4. Response of ethylene propylene diene monomer rubber (EPDM) to simulant Hanford tank waste

    SciTech Connect

    NIGREY,PAUL J.

    2000-02-01

    This report presents the findings of the Chemical Compatibility Program developed to evaluate plastic packaging components that may be incorporated in packaging mixed-waste forms for transportation. Consistent with the methodology outlined in this report, the author performed the second phase of this experimental program to determine the effects of simulant Hanford tank mixed wastes on packaging seal materials. That effort involved the comprehensive testing of five plastic liner materials in an aqueous mixed-waste simulant. The testing protocol involved exposing the materials to {approximately}143, 286, 571, and 3,670 krad of gamma radiation and was followed by 7-, 14-, 28-, 180-day exposures to the waste simulant at 18, 50, and 60 C. Ethylene propylene diene monomer (EPDM) rubber samples subjected to the same protocol were then evaluated by measuring seven material properties: specific gravity, dimensional changes, mass changes, hardness, compression set, vapor transport rates, and tensile properties. The author has determined that EPDM rubber has excellent resistance to radiation, this simulant, and a combination of these factors. These results suggest that EPDM is an excellent seal material to withstand aqueous mixed wastes having similar composition to the one used in this study.

  5. Synthesis of brominated acenaphthylenes and their flame-retardant effects on ethylene-propylene-diene terpolymer

    SciTech Connect

    Morita, Y.; Hagiwara, M.

    1982-09-01

    Bromoacenaphthylenes and their condensates as flame-retardant reagents were synthesized by bromination of acenaphthylene using ZnCl/sub 2/ - CF/sub 3/COOH or FeCl/sub 3/ as catalysts and subsequent dehydrobromination. The chief components were identified as bromoacenaphthylene monomers when ZnCl/sub 2/ - CF/sub 3/COOH were used, and as their condensates (mostly trimers) in the case of FeCl/sub 3/. Their performance as flame-retardant reagents for ethylene-propylene-diene terpolymer (EPDM) was evaluated by measuring the oxygen index of finished compounds, and flammability by a vertical flammability test based on UL-94-VO. Both the monomers and the condensates demonstrated high flame-retardant effectiveness. The high efficiency was attributed to their excellent dispersity in the base polymer and their characteristic thermal decomposition behavior. In thermal gravimetric analysis (TGA), they decomposed in a very wide range of temperature (ca.200-560/sup 0/C), which covers the decomposition range of EPDM. This was attributed to the existence of bromines of different thermal stabilities in one molecule. This paper is a part of a series of studies to develop new flame retardants which can give high flame retardancy as well as stabilty against ionizing radiation to EPDM.

  6. Synthesis of Highly Functionalized Tri- and Tetrasubstituted Alkenes via Pd-Catalyzed 1,2-Hydrovinylation of Terminal 1,3-Dienes

    PubMed Central

    2016-01-01

    An efficient method for the construction of Csp2–Csp3 bond in a regio- and stereoselective fashion involving 1,3-terminal dienes, enol triflates/nonaflates, and sodium formate under Pd(0)-catalysis is described. The three component assembly allows trapping of a π-allyl intermediate, after the initial migratory insertion of the diene, by a hydride source that leads to structurally complex and synthetically challenging tri- and tetrasubstituted alkene building blocks. PMID:25555197

  7. Aza-Morita-Baylis-Hillman reactions and cyclizations of conjugated dienes activated by sulfone, ester, and keto groups.

    PubMed

    Sorbetti, Jovina M; Clary, Kristen N; Rankic, Danica A; Wulff, Jeremy E; Parvez, Masood; Back, Thomas G

    2007-04-27

    The aza-Morita-Baylis-Hillman reactions of aldimines 2 with several activated conjugated dienes were found to proceed smoothly in DMF in the presence of 3-hydroxyquinuclidine (HQD). Imines 2 reacted with 1-(p-toluenesulfonyl)-1,3-butadiene (3), methyl 2,4-pentadienoate (6), hexa-3,5-dien-2-one (7), and 1-phenylpenta-2,4-dien-1-one (8) to afford adducts 4, 13, 14, and 15, respectively. While products 4, 13, and 15 were formed as E,Z mixtures, adducts 14 were obtained as essentially pure E-isomers. Cyclization of the E-isomers of the products derived from the dienyl sulfone 3 and the dienoate ester 6 occurred via intramolecular conjugate addition under base-catalyzed conditions to afford functionalized piperidines 5 and 16, respectively. The aza-Morita-Baylis-Hillman reaction and subsequent cyclization of the imine 2a with 3 were also carried out as a one-pot reaction, while the reaction mixture was simultaneously irradiated at 300 nm to effect the photoisomerization of the unreactive Z-adduct of the corresponding 4 to the more reactive E-isomer. PMID:17381156

  8. In vivo anticancer, anti-inflammatory, and toxicity studies of mixed-ligand Cu(II) complexes of dien and its Schiff dibases with heterocyclic aldehydes and 2-amino-2-thiazoline. Crystal structure of [Cu(dien)(Br)(2a-2tzn)](Br)(H(2)O).

    PubMed

    Chaviara, A Th; Christidis, P C; Papageorgiou, A; Chrysogelou, E; Hadjipavlou-Litina, D J; Bolos, C A

    2005-11-01

    A new series of complexes of the type [Cu(dien)(2a-2tzn)Y(2)] and [Cu(dienXX)(2a-2tzn)Y(2)], where dien=diethylenetriamine and dienXX=Schiff dibase of diethylenetriamine formed with 2-furaldehyde (dienOO), 2-thiophenecarboxaldehyde (dienSS), or pyrrol-2-carboxaldehyde (dienNN); Y=Cl, Br or NO(3); and 2a-2tzn=2-amino-2-thiazoline, were synthesized and their structure established by C, H, N and Cu analysis; IR and electronic spectra; magnetic susceptibility; and molar conductivity. The isolated complexes are monomers, paramagnetic, and electrolytes of types 1:1 or 1:2. In both types of solid state complexes, [Cu(dien)(2a-2tzn)Y(2)] and [Cu(dienXX)(2a-2tzn)Y(2)], dien and its Schiff dibases are bonded to Cu(II) in a tridentate fashion through 3N atoms. The coordination sphere is completed by the endocyclic nitrogen of the thiazoline moiety and by two Cl, Br, or NO(3) groups with distorted octahedral geometry. The proposed structure of these compounds was supported by X-ray analysis of [Cu(dien)(Br)(2a-2tzn)](Br)(H(2)O). The coordination polyhedron around the copper atom can be described as a distorted square pyramid [Cu(dien)(Br)(2a-2tzn)](+). Its basal plane is occupied by the four nitrogen atoms of the dien and thiazoline ligands with Cu-N distances ranging between 1.996(6) and 2.032(3)A, and the axial position is occupied by one of the two bromine atoms (Br1) with a Cu1-Br1 bond distance of 2.782(1)A. The second bromine atom (Br2) is 4.694(2)A from the copper atom, which exists as a discrete anion and is responsible for the cationic nature of the complex. Results regarding toxicity, antitumor, and anti-inflammatory activities of the investigated compounds are promising and allow the selection of a lead compound for further biological studies. PMID:16144711

  9. Triarylphosphine Ligands with Hemilabile Alkoxy Groups. Ligands for Nickel(II)-Catalyzed Olefin Dimerization Reactions. Hydrovinylation of Vi-nylarenes, 1,3-Dienes, and Cycloisomerization of 1,6-Dienes

    PubMed Central

    Biswas, Souvagya; Zhang, Aibin; Raya, Balaram

    2014-01-01

    Substitution of one of the phenyl groups of triphenylphosphine with a 2-benzyloxy-, 2-benzyloxymethyl- or 2-benzyloxyethyl-phenyl moiety results in a set of simple ligands, which exhibit strikingly different behaviour in various nickel(II)-catalyzed olefin dimerization reactions. Complexes of ligands with 2-benzyloxyphenyl-, 2-benzyloxymethylphenyl-diphenylphosphine (L5 and L6 respectively) are most active for hydrovinylation (HV) of vinylarenes, with the former leading to extensive isomerization of the primary 3-aryl-1-butenes into the conjugated 2-aryl-2-butenes even at −55 °C. However, 2-benzyloxymethyl-substituted ligand L6 is slightly less active, leading up to quantitative yields of the primary products of HV at ambient temperature with no trace of isomerization, thus providing the best option for a practical synthesis of these compounds. In sharp contrast, hydrovinylation of a variety of 1,3-dienes is best catalyzed by nickel(II)-complexes of 2-benzyloxyphenyldiphenylphosphine, L5. The other two ligands, 2-benzyloxymethyl-(L6) and 2-benzyloxyethyl-diphenylphosphine (L7) are much less effective in the HV of 1,3-dienes. Nickel(II)-catalyzed cycloisomerization of 1,6-dienes into methylenecyclopentanes, a reaction mechanistically related to the other hydrovinylation reactions, is also uniquely effected by nickel(II)-complexes of L5, but not of L6 or L7. In an attempt to prepare authentic samples of the methylencyclohexane products, nickel(II)-complexes of N-heterocyclic carbene-ligands were examined. In sharp contrast to the phosphines, which give the methylenecyclopentanes, methylenecyclohexanes are the major products in the (N-heterocyclic carbene)nickel(II)-mediated reactions. PMID:25395919

  10. Triarylphosphine Ligands with Hemilabile Alkoxy Groups. Ligands for Nickel(II)-Catalyzed Olefin Dimerization Reactions. Hydrovinylation of Vi-nylarenes, 1,3-Dienes, and Cycloisomerization of 1,6-Dienes.

    PubMed

    Biswas, Souvagya; Zhang, Aibin; Raya, Balaram; RajanBabu, T V

    2014-07-01

    Substitution of one of the phenyl groups of triphenylphosphine with a 2-benzyloxy-, 2-benzyloxymethyl- or 2-benzyloxyethyl-phenyl moiety results in a set of simple ligands, which exhibit strikingly different behaviour in various nickel(II)-catalyzed olefin dimerization reactions. Complexes of ligands with 2-benzyloxyphenyl-, 2-benzyloxymethylphenyl-diphenylphosphine (L5 and L6 respectively) are most active for hydrovinylation (HV) of vinylarenes, with the former leading to extensive isomerization of the primary 3-aryl-1-butenes into the conjugated 2-aryl-2-butenes even at -55 °C. However, 2-benzyloxymethyl-substituted ligand L6 is slightly less active, leading up to quantitative yields of the primary products of HV at ambient temperature with no trace of isomerization, thus providing the best option for a practical synthesis of these compounds. In sharp contrast, hydrovinylation of a variety of 1,3-dienes is best catalyzed by nickel(II)-complexes of 2-benzyloxyphenyldiphenylphosphine, L5. The other two ligands, 2-benzyloxymethyl-(L6) and 2-benzyloxyethyl-diphenylphosphine (L7) are much less effective in the HV of 1,3-dienes. Nickel(II)-catalyzed cycloisomerization of 1,6-dienes into methylenecyclopentanes, a reaction mechanistically related to the other hydrovinylation reactions, is also uniquely effected by nickel(II)-complexes of L5, but not of L6 or L7. In an attempt to prepare authentic samples of the methylencyclohexane products, nickel(II)-complexes of N-heterocyclic carbene-ligands were examined. In sharp contrast to the phosphines, which give the methylenecyclopentanes, methylenecyclohexanes are the major products in the (N-heterocyclic carbene)nickel(II)-mediated reactions. PMID:25395919

  11. Soft Propargylic Deprotonation: Designed Ligand Enables Au-Catalyzed Isomerization of Alkynes to 1,3-Dienes

    PubMed Central

    2015-01-01

    By functionalizing the privileged biphenyl-2-ylphosphine with a basic amino group at the rarely explored 3′ position, the derived gold(I) complex possesses orthogonally positioned “push” and “pull” forces, which enable for the first time soft propargylic deprotonation and permit the bridging of a difference of >26 pKa units (in DMSO) between a propargylic hydrogen and a protonated tertiary aniline. The application of this design led to efficient isomerization of alkynes into versatile 1,3-dienes with synthetically useful scope under mild reaction conditions. PMID:24911158

  12. Tricyclo­[6.2.1.02,7]undeca-4,9-diene-3,6-dione

    PubMed Central

    Wang, Chongchen

    2008-01-01

    The title compound, C11H10O2, crystallizes with two independent mol­ecules in the asymmetric unit. In one mol­ecule, the dihedral angle between the mean planes of the C—C=C—C group of the diene unit and essentially planar cyclo­hexene ring is 51.07 (9)°, while in the other mol­ecule it is 54.49 (12)°. In the crystal structure, weak inter­molecular C—H⋯O inter­actions link the mol­ecules into columns along the b axis. PMID:21201200

  13. Synthesis and behavior of novel sulfonated water-soluble N-heterocyclic carbene (η(4)-diene) platinum(0) complexes.

    PubMed

    Ruiz-Varilla, Andrea M; Baquero, Edwin A; Silbestri, Gustavo F; Gonzalez-Arellano, Camino; de Jesús, Ernesto; Flores, Juan C

    2015-11-14

    A series of water-soluble (NHC)Pt(0)(dvtms) and (NHC)Pt(0)(AE) complexes containing different sulfonated NHC ligands (dvtms = divinyltetramethyldisiloxane and AE = diallyl ether) are reported. The dvtms compounds have been found to be quite robust and to display some conformational rigidity, whereas their AE counterparts are less stable and more flexible. The catalytic evaluation of these complexes in the hydrosilylation of alkynes in water revealed no benefits in favor of the complexes containing the more labile spectator diene (AE), and a fairly regular catalytic behavior for all complexes that restricts the location of the sulfonate group to the proximity of the metal site. PMID:26346995

  14. Bicyclo[3.2.1]octa-3,6-dien-2-yl cation: a bishomoantiaromate.

    PubMed

    Volz, Heinrich; Shin, Jung-Hyu

    2006-03-17

    Antiaromatic compounds with a closed loop of 4n p-electrons are relatively unstable and often difficult to study. We report in this article the synthesis of alcohols 2-(4'-fluorophenyl)bicyclo[3.2.1]octan-2-ol 11, 2-(4'-fluorophenyl)bicyclo[3.2.1]oct-3-en-2-ol 12, and 2-(4'-fluorophenyl)bicyclo[3.2.1]octa-3,6-dien-2-ol 13 and their transformations into corresponding carbocations 14-16, respectively, in a superacidic medium (FSO3H/SO2ClF) at -120 degrees C. Cations 14-16 are characterized by NMR analysis (1H, 13C, 19F), and 15 and 16 are further characterized by quenching in NaOCH3/H3COH at -120 degrees C. The relative stabilities of 14-16 are determined experimentally by 19F NMR spectroscopy. Cation 16 is found to be experimentally less stable than cation 15 by 3.7 kcal/mol. DFT calculations (structure and energy: B3LYP/6-31G(d); NMR: B3LYP/6-311+G(2d,p)) are performed for alcohols 11-13 and bicyclo[3.2.1]octyl cations 6, 7, 9, 14-16, 26, 28, and 30. In the case of 11-16, data from DFT calculations is in good agreement with experimental data. Because 6,7-dimethylenebicyclo[3.2.1]oct-3-en-2-yl cation 26 is more stable than cation 7 by 1.69 kcal/mol, the inductive effect of sp(2)-hybridized carbon atoms C6 and C7 in carbocations 6 and 16 cannot be the reason for the destabilization of 6 relative to 7 and 16 relative to 15. Destabilization of 6 relative to 7 and 16 relative to 15 and the calculated NICS of 6 (+4.17 ppm) and 16(+3.3 ppm) document that 6 and 16 are bishomoantiaromates. PMID:16526766

  15. Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien)2(μ-1κ,2κ2-AsS4)]n (Ln==Sm, Eu, Gd) and [Ln(dien)2(1κ2-AsS4)] (Ln==Tb, Dy, Ho)

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian

    2013-10-01

    Solvothermal reactions of Ln2O3, As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien)2(μ-1κ,2κ2-AsS4)]n [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien)2(1κ2-AsS4)] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln2O3 oxides were converted to [Ln(dien)2]3+ complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS4 unit. In 1-3, the AsS4 units interconnect the [Ln(dien)2]3+ cations via Ln-S bonds as tridentate μ-1κ,2κ2-AsS4 bridging ligands, resulting in the neutral coordination polymers [Ln(dien)2(μ-1κ,2κ2-AsS4)]n (Ln1). In 4-6, the AsS4 units coordinate with the Ln3+ ion of [Ln(dien)2]3+ as 1κ2-AsS4 chelating ligands to form neutral coordination compounds [Ln(dien)2(1κ2-AsS4)] (Ln2). The Ln3+ ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln3+ ions. Optical absorption spectra showed that 1-6 have potential use as semiconductors with the band gaps in the range 2.18-3.21 eV.

  16. Ambient temperature ligation of diene functional polymer and peptide strands onto cellulose via photochemical and thermal protocols.

    PubMed

    Tischer, Thomas; Claus, Tanja K; Oehlenschlaeger, Kim K; Trouillet, Vanessa; Bruns, Michael; Welle, Alexander; Linkert, Katharina; Goldmann, Anja S; Börner, Hans G; Barner-Kowollik, Christopher

    2014-06-01

    In the present contribution, two novel ambient temperature avenues are introduced to functionalize solid cellulose substrates in a modular fashion with synthetic polymer strands (poly(trifluoro ethyl methacrylate), PTFEMA, Mn = 4400 g mol(-1) , Đ = 1.18) and an Arg-Gly-Asp (RGD) containing peptide sequence. Both protocols rely on a hetero Diels-Alder reaction between an activated thiocarbonyl functionality and a diene species. In the first-thermally activated-protocol, the cellulose features surface-expressed thiocarbonylthio compounds, which readily react with diene terminal macromolecules at ambient temperature. In the second protocol, the reactive ene species are photochemically generated based on a phenacyl sulfide-decorated cellulose surface, which upon irradiation expresses highly reactive thioaldehyde species. The generated functional hybrid surfaces are characterized in-depth via ToF-SIMS and XPS analysis, revealing the successful covalent attachment of the grafted materials, including the spatially resolved patterning of both synthetic polymers and peptide strands using the photochemical protocol. The study thus provides a versatile platform technology for solid cellulose substrate modification via efficient thermal and photochemical ligation strategies. PMID:24706565

  17. A gold-catalyzed unique cycloisomerization of 1,5-enynes: efficient formation of 1-carboxycyclohexa-1,4-dienes and carboxyarenes.

    PubMed

    Wang, Shaozhong; Zhang, Liming

    2006-11-01

    A novel Au-catalyzed migratory cycloisomerization strategy is advanced. Implementation of this strategy led to the development of a unique Au-catalyzed 1,5-enyne cycloisomerizatioin involving carboxy migration and Au-mediated C-C single bond formation. 1-Carboxycyclohexa-1,4-dienes and carboxyarenes can be prepared with good efficiency and with flexible substitution patterns. PMID:17076498

  18. Development of palladium-carbene catalysts for telomerization and dimerization of 1,3-dienes: from basic research to industrial applications.

    PubMed

    Clement, Nicolas D; Routaboul, Lucie; Grotevendt, Anne; Jackstell, Ralf; Beller, Matthias

    2008-01-01

    The following account summarises recent developments in the area of palladium-catalysed telomerisation and dimerisation reactions of 1,3-dienes. The most active types of catalyst, palladium-carbene complexes, were tested in pilot plant and proved to be industrially viable. PMID:18680130

  19. Cu(I)-catalyzed diamination of conjugated dienes. Complementary regioselectivity from two distinct mechanistic pathways involving Cu(II) and Cu(III) species.

    PubMed

    Zhao, Baoguo; Peng, Xingao; Zhu, Yingguang; Ramirez, Thomas A; Cornwall, Richard G; Shi, Yian

    2011-12-28

    Conjugated dienes can be diaminated at the internal and/or terminal double bonds using Cu(I) as catalyst and N,N-di-t-butyldiaziridinone (1) as nitrogen source. The regioselectivity is highly dependent upon the choice of Cu(I) catalyst and the substituents on diene substrates. The diamination likely proceeds via two mechanistically distinct pathways. The N-N bond of N,N-di-t-butyldiaziridinone (1) is first homolytically cleaved by the Cu(I) catalyst to form four-membered Cu(III) species A and Cu(II) radical species B, which are in rapid equilibrium. The internal diamination likely proceeds in a concerted manner via Cu(III) species A, and the terminal diamination likely involves Cu(II) radical species B. Kinetic studies have shown that the diamination is first-order in N,N-di-t-butyldiaziridinone (1), zero-order in olefin, and first-order in total Cu(I) catalyst, and the cleavage of the N-N bond of 1 by the Cu(I) catalyst is the rate-determining step. The internal diamination is favored by use of CuBr without ligand and electron-rich dienes. The terminal diamination is favored when using CuCl-L and dienes with radical-stabilizing groups. PMID:22081888

  20. Cu(I)-Catalyzed Diamination of Conjugated Dienes. Complementary Regioselectivity from Two Distinct Mechanistic Pathways Involving Cu(II) and Cu(III) Species

    PubMed Central

    Zhao, Baoguo; Peng, Xingao; Zhu, Yingguang; Ramirez, Thomas A.; Cornwall, Richard G.

    2011-01-01

    Conjugated dienes can be diaminated at the internal and/or terminal double bonds using Cu(I) as catalyst and N,N-di-t-butyldiaziridinone (1) as nitrogen source. The regioselectivity is highly dependent upon the choice of Cu(I) catalyst and the substituents on diene substrates. The diamination likely proceeds via two mechanistically distinct pathways. The N-N bond of N,N-di-t-butyldiaziridinone (1) is first homolytically cleaved by the Cu(I) catalyst to form four-membered Cu(III) species A and Cu(II) radical species B, which are in rapid equilibrium. The internal diamination likely proceeds in a concerted manner via Cu(III) species A and the terminal diamination likely involves Cu(II) radical species B. Kinetic studies have shown that the diamination is first-order in N,N-di-t-butyldiaziridinone (1), zero-order in olefin, first-order in total Cu(I) catalyst, and the cleavage of the N-N bond of 1 by the Cu(I) catalyst is the rate-determining step. The internal diamination is favored by use of CuBr without ligand and electron-rich dienes. The terminal diamination is favored when using CuCl-L and dienes with radical-stabilizing groups. PMID:22081888

  1. Computational Examination of (4 + 3) versus (3 + 2) Cycloaddition in the Interception of Nazarov Reactions of Allenyl Vinyl Ketones by Dienes.

    PubMed

    Li, Zhe; Boyd, Russell J; Burnell, D Jean

    2015-12-18

    A computational examination of the tandem Nazarov/cycloaddition process involving an allenyl vinyl ketone with a diene has been carried out using the ωB97X-D/6-311++G(d,p)//ωB97X-D/6-31+G(d,p) method with solvation modeled by SMD-PCM. The barrier for the initial Lewis acid mediated Nazarov reaction, which provided the intermediate cyclic oxylallyl cation, was higher than that for any subsequent cycloaddition. The barrier for the first step of a subsequent stepwise reaction did not vary much with the diene, and the lowest barrier was with the diene in its s-trans conformation. Stepwise formation of a (4 + 3) cycloaddition product was not energetically feasible, but (3 + 2) cycloaddition products could have been produced through low energy pathways. The barrier for a concerted (4 + 3) cycloaddition did depend upon the diene, which was always in an s-cis geometry. The barriers for the compact and the extended geometries for the transition states of (4 + 3) cycloadditions were not much different. PMID:26595587

  2. Synthesis, crystal growth and characterization of 1,5-diphenylpenta-1,4-dien-3-one: An organic crystal

    NASA Astrophysics Data System (ADS)

    Vanchinathan, K.; Bhagavannarayana, G.; Muthu, K.; Meenakshisundaram, S. P.

    2011-11-01

    1,5-Diphenylpenta-1,4-dien-3-one ( dibenzalacetone, DBA) was synthesized by a base-catalyzed aldol condensation reaction between benzaldehyde and acetone. High quality single crystals have been grown by the slow evaporation of ethanol solution and the crystal belongs to monoclinic system with centrosymmetric space group C 2/c. The DBA crystals are transparent in the entire visible region and have a lower optical cutoff at ∼440 nm. It is stable up to 119 °C and has a good chemical stability. The high resolution X-ray diffraction curve (DC) indicates that the specimen is free from structural grain boundaries. Molecular packing leads to a centrosymmetric arrangement resulting in zero second harmonic generation (SHG; χ(2)=0) efficiency.

  3. Surface modification of argon/oxygen plasma treated vulcanized ethylene propylene diene polymethylene surfaces for improved adhesion with natural rubber

    NASA Astrophysics Data System (ADS)

    Basak, Ganesh C.; Bandyopadhyay, Abhijit; Neogi, Sudarsan; Bhowmick, Anil K.

    2011-01-01

    Vulcanized ethylene propylene diene polymethylene (EPDM) rubber surface was treated in a radio frequency capacitatively coupled low pressure argon/oxygen plasma to improve adhesion with compounded natural rubber (NR) during co-vulcanization. The plasma modified surfaces were analyzed by means of contact angle measurement, surface energy, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive X-ray sulfur mapping and atomic force microscopy. Several experimental variables such as plasma power, length of exposure time and composition of the argon-oxygen gas mixture were considered. It was delineated that plasma treatment changed both surface composition and roughness, and consequently increased peel strength. The change in surface composition was mainly ascribed to the formation of C-O and -Cdbnd O functional groups on the vulcanized surfaces. A maximum of 98% improvement in peel strength was observed after plasma treatment.

  4. Synthesis, crystal structure and properties of [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} with mixed-valent Ge centers

    SciTech Connect

    Yue, Cheng-Yang; Yuan, Zhuang-Dong; Zhang, Lu-Ge; Wang, Ya-Bai; Liu, Guo-Dong; Gong, Liao-Kuo; Lei, Xiao-Wu

    2013-10-15

    One new manganese thiogermanate, [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} (dien=diethylenetriamine), was prepared under mild solvothermal conditions and structurally and spectroscopically characterized. The title compound crystallizes in the orthorhombic system, chiral space group P2{sub 1}2{sub 1}2{sub 1} (no. 19) with a=9.113(4) Å, b=12.475(5) Å, c=17.077(7) Å, V=1941.5(15) Å{sup 3} and Z=4. Its structure features a three-dimensional (3D) network composed of a one-dimensional (1D) [Ge{sub 2}S{sub 4}]{sup 2−} anionic chain and a [(dien){sub 2}Mn]{sup 2+} complex interconnected via various hydrogen bonds. The most interesting structural feature of the compound is the presence of two different oxidation states of germanium centers in the 1D [Ge{sub 2}S{sub 4}]{sup 2−} chain, which is also supported by the result of X-ray photoelectron spectroscopy measurement. The optical property of the title compound has also been studied by UV–vis spectra. - Graphical abstract: One new thiogermanate, [(dien){sub 2}Mn]Ge{sub 2}S{sub 4}, contains a one-dimensional [Ge{sub 2}S{sub 4}]{sup 2−} anionic chain with two different oxidation states of germanium centers. Display Omitted - Highlights: • One new manganese thiogermanate [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} was prepared. • The compound features 1D [Ge{sub 2}S{sub 4}]{sup 2−} chain composed of [Ge{sup II}S{sub 4}] and [Ge{sup IV}S{sub 4}] tetrahedra. • The first example of inorganic–organic hybrid thiogermanates with mixed valent Ge centers.

  5. Transport and bioaccumulation of polychlorinated dibenzo-p-dioxins and dibenzofurans at the Bien Hoa Agent Orange hotspot in Vietnam.

    PubMed

    Van Thuong, Nguyen; Hung, Nguyen Xuan; Mo, Nguyen Thi; Thang, Nguyen Manh; Huy, Pham Quang; Van Binh, Hoang; Nam, Vu Duc; Van Thuy, Nguyen; Son, Le Ke; Minh, Nguyen Hung

    2015-10-01

    The Bien Hoa airbase (south of Vietnam) is known as one of the Agent Orange hotspots which have been seriously contaminated by Agent Orange/dioxin during the Vietnam War. Hundreds of samples including soil, sediment and fish were collected at the Bien Hoa Agent Orange hotspot for assessment of the environmental contamination caused by dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The toxicity equivalency quotient (TEQ) concentration of PCDD/Fs in soil and sediment varied from 7.6 to 962,000 and 17 to 4860 pg/g dry wt, respectively, implying very high contamination of PCDD/Fs in several areas. PCDD/F levels in fish ranged between 1.8 and 288 pg/g TEQ wet wt and was generally higher than advisory guidelines for food consumption. 2,3,7,8-Tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) contributed 66-99 % of TEQ for most of the samples, suggesting 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) from Agent Orange as the major source of the contamination. The vertical transport of PCDD/Fs was observed in soil column with high TEQ levels above 1000 pg/g dry wt (Vietnamese limit for necessary remediation activities- TCVN 8183:2009 (2009)) even at a depth of 1.8 m. The vertical transport of PCDD/Fs has probably mainly taken place during the "Ranch Hand" defoliant spray activities due to the leaks and spills of phenoxy herbicides and solvents. The congener patterns suggest that transports of PCDD/Fs by weathering processes have led to their redistribution in the low-land areas. Also, an estimate for the total volume of contaminated soil requiring remediation to meet Vietnamese regulatory limits is provided. PMID:25510612

  6. Direct, redox-neutral prenylation and geranylation of secondary carbinol C-H bonds: C4-regioselectivity in ruthenium-catalyzed C-C couplings of dienes to α-hydroxy esters.

    PubMed

    Leung, Joyce C; Geary, Laina M; Chen, Te-Yu; Zbieg, Jason R; Krische, Michael J

    2012-09-26

    The ruthenium catalyst generated in situ from Ru(3)(CO)(12) and tricyclohexylphosphine, PCy(3), promotes the redox-neutral C-C coupling of aryl-substituted α-hydroxy esters to isoprene and myrcene at the diene C4-position, resulting in direct carbinol C-H prenylation and geranylation, respectively. This process enables direct conversion of secondary to tertiary alcohols in the absence of stoichiometric byproducts or premetalated reagents, and is the first example of C4-regioselectivity in catalytic C-C couplings of 2-substituted dienes to carbonyl partners. Mechanistic studies corroborate a catalytic cycle involving diene-carbonyl oxidative coupling. PMID:22985393

  7. A new C12 alcohol identified as a sex pheromone and a trail-following pheromone in termites: the diene (Z,Z)-dodeca-3,6-dien-1-ol.

    PubMed

    Robert, Alain; Peppuy, Alexis; Sémon, Etienne; Boyer, François D; Lacey, Michael J; Bordereau, Christian

    2004-01-01

    The diunsaturated C12 alcohol (Z,Z)-dodeca-3,6-dien-1-ol (dodecadienol) has been characterized by GC-MS and FTIR as a novel releaser pheromone in termites. This alcohol identified in Ancistrotermes pakistanicus (Termitidae, Macrotermitinae) possesses a double pheromonal function which again illustrates the chemical parsimony of termites compared with other social insects. In workers, dodecadienol elicits trail-following at a very low concentration (activity threshold at 0.1 pg/cm of trail); in male alates it induces trail-following at a low concentration (1-10 pg/cm) and sexual attraction at a higher concentration (about 1 ng). Traces of the monounsaturated C12 alcohol (Z)-dodec-3-en-1-ol (dodecenol), known as a trail pheromone of several Macrotermitinae, were also found in the sternal gland extracts of A. pakistanicus, although only dodecadienol was present at the surface of the sternal gland. Workers of A. pakistanicus are not sensitive to dodecenol, but they are as sensitive to dodecatrienol as to dodecadienol. However, in the study area (Vietnam), A. pakistanicus is living in sympatry only with those Macrotermitinae using dodecenol as a trail pheromone, the foraging populations therefore being well isolated through their respective trail pheromones. The presence of three types of unsaturated C12 alcohols as releaser pheromones in the only Macrotermitinae subfamily is discussed, and a possible biosynthetic pathway from linoleic acid is proposed for dodecadienol. PMID:14740102

  8. Oxidative Cyclization of 1,5-Dienes with Hydrogen Peroxide Catalyzed by an Osmium(III) Complex: Synthesis of cis-Tetrahydrofurans.

    PubMed

    Sugimoto, Hideki; Kanetake, Takayuki; Maeda, Kazuki; Itoh, Shinobu

    2016-03-18

    Stereoselective oxidative cyclization of 1,5-dienes with hydrogen peroxide catalyzed by [Os(III)(OH)(H2O)(L-N4Me2)](PF6)2 (1: L-N4Me2 = N,N'-dimethyl-2,11-diaza-[3,3](2,6)pyridinophane) is explored. 1,5-Dienes involving geraniol derivatives are converted to the corresponding tetrahydrofurans in modest to high yields. The products exclusively have the cis-conformation with respect to the substituents at the 2- and 5-positions of the tetrahydrofuran ring. The products also have a syn-conformation with respect to the furan oxygen atom and the hydroxyl groups. Mechanistic studies including a direct reaction of the oxo-hydroxo-osmium(V) complex, 2, with a dihydroxylated geraniol derivative are performed. PMID:26950609

  9. Base-catalyzed intramolecular hydroamination of cyclohexa-2,5-dienes: insights into the mechanism through DFT calculations and application to the total synthesis of epi-elwesine.

    PubMed

    Rousseau, Géraldine; Lebeuf, Raphaël; Schenk, Kurt; Castet, Frédéric; Robert, Frédéric; Landais, Yannick

    2014-11-01

    The base-catalyzed intramolecular hydroamination of 1-ethylaminocyclohexa-2,5-dienes is described. The transformation proceeds through isomerization of the cyclohexa-1,4-dienyl fragment into the corresponding conjugated 1,3-diene prior to the hydroamination step. Attaching a chiral glycinol ether auxiliary on the amino group allows the protonation to occur with complete diastereocontrol. The resulting lithium amide then adds onto the 1,3-dienyl moiety, affording the desired fused pyrrolidine ring along with the corresponding lithium allylic anion. Protonation of the latter then proceeds with high regiocontrol to favor the resulting allylic amines. In contrast, when the reaction was performed on primary amines, fused pyrrolidines bearing a homoallylic amino group were obtained. The stereochemical course of the process and determination of the reaction pathways were established based on calculations performed at the DFT level. Finally, application of the methodology to the enantioselective synthesis of (+)-epi-elwesine, a crinane alkaloid, is described. PMID:25223607

  10. A simple and efficient approach to the synthesis of endo and exo bicyclo[6.1.0]nona-3,5-diene-9-carboxaldehyde.

    PubMed

    Ghandi, Mehdi; Mashayekhi, Gholamreza

    2007-01-01

    Monobromination of 1,5-cyclooctadiene, followed by cyclopropanation with ethyl diazoacetate, led to the formation of endo and exo ethyl 4,5-dibromobicyclo[6.1.0]nonane-9-carboxylates 3a and 3b. Bis-dehydrobromination of 3a and 3b using 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) afforded the endo and exo ethyl bicyclo[6.1.0]nona-3,5-diene-9-carboxylates 4a and 4b. Reduction of these compounds to the corresponding alcohols 5a and 5b and subsequent oxidation with pyridinium chlorochromate (PCC) resulted in the formation of the target compounds endo and exo bicyclo[6.1.0]nona-3,5-diene-9-carboxaldehydes 6a and 6b. PMID:17978767

  11. Highly Chemo- and Regioselective Construction of Spirocarbocycles by a Pd(0)-Catalyzed Dearomatization of Phenol-Based Biaryls with 1,3-Dienes.

    PubMed

    Luo, Lei; Zheng, Huayu; Liu, Jingjing; Wang, Hui; Wang, Yaoyu; Luan, Xinjun

    2016-05-01

    A novel Pd(0)-catalyzed intermolecular carbocyclization of phenol-derived biaryls with 1,3-dienes has been implemented through a sequence of oxidative addition to the C-I bond, regioselective olefin insertion, and allylative dearomatization. This method provides a broad range of attractive spirocyclic compounds bearing two contiguous tertiary/quaternary carbon centers in good yields with excellent chemoselectivity and regioselectivity. Moreover, preliminary results indicate that asymmetric control of this process is feasible with chiral ligands. PMID:27120015

  12. Environmental Health Risk Assessment of Dioxin Exposure through Foods in a Dioxin Hot Spot—Bien Hoa City, Vietnam

    PubMed Central

    Tuyet-Hanh, Tran Thi; Vu-Anh, Le; Ngoc-Bich, Nguyen; Tenkate, Thomas

    2010-01-01

    This study used the Australian Environmental Health Risk Assessment Framework to assess the human health risk of dioxin exposure through foods for local residents in two wards of Bien Hoa City, Vietnam. These wards are known hot-spots for dioxin and a range of stakeholders from central government to local levels were involved in this process. Publications on dioxin characteristics and toxicity were reviewed and dioxin concentrations in local soil, mud, foods, milk and blood samples were used as data for this risk assessment. A food frequency survey of 400 randomly selected households in these wards was conducted to provide data for exposure assessment. Results showed that local residents who had consumed locally cultivated foods, especially fresh water fish and bottom-feeding fish, free-ranging chicken, duck, and beef were at a very high risk, with their daily dioxin intake far exceeding the tolerable daily intake recommended by the WHO. Based on the results of this assessment, a multifaceted risk management program was developed and has been recognized as the first public health program ever to have been implemented in Vietnam to reduce the risks of dioxin exposure at dioxin hot-spots. PMID:20623031

  13. Diene Valepotriates from Valeriana glechomifolia Prevent Lipopolysaccharide-Induced Sickness and Depressive-Like Behavior in Mice.

    PubMed

    Müller, Liz G; Borsoi, Milene; Stolz, Eveline D; Herzfeldt, Vivian; Viana, Alice F; Ravazzolo, Ana Paula; Rates, Stela Maris K

    2015-01-01

    Valeriana glechomifolia, a native species from southern Brazil, presents antidepressant-like activity and diene valepotriates (VAL) contribute to the pharmacological properties of the genus. It is known that depression can develop on an inflammation background in vulnerable patients and antidepressants present anti-inflammatory properties. We investigated the effects of VAL (10 mg/kg, p.o.) on sickness and depressive-like behaviors as well as proinflammatory cytokines (IL-1β and TNF-α) and BDNF expression in the cortex of mice exposed to a 5 min swimming session (as a stressful stimulus) 30 min before the E. coli LPS injection (600 µg/kg, i.p.). The forced swim + LPS induced sickness and depressive-like behaviors, increased the cortical expression of IL-1β and TNF-α, and decreased BDNF expression. VAL was orally administered to mice 1 h before (pretreatment) or 5 h after (posttreatment) E. coli LPS injection. The pretreatment with VAL restored the behavioral alterations and the expression of cortical proinflammatory cytokines in LPS-injected animals but had no effects on BDNF expression, while the posttreatment rescued only behavioral alterations. Our results demonstrate for the first time the positive effects of VAL in an experimental model of depression associated with inflammation, providing new data on the range of action of these molecules. PMID:26170871

  14. Radiation processed polychloroprene-co-ethylene-propene diene terpolymer blends: Effect of radiation vulcanization on solvent transport kinetics

    NASA Astrophysics Data System (ADS)

    Dubey, K. A.; Bhardwaj, Y. K.; Chaudhari, C. V.; Kumar, Virendra; Goel, N. K.; Sabharwal, S.

    2009-03-01

    Blends of polychloroprene rubber (PCR) and ethylene propylene diene terpolymer rubber (EPDM) of different compositions were made and exposed to different gamma radiation doses. The radiation sensitivity and radiation vulcanization efficiency of blends was estimated by gel-content analysis, Charlesby-Pinner parameter determination and crosslinking density measurements. Gamma radiation induced crosslinking was most efficient for EPDM ( p0/ q0 ˜ 0.08), whereas it was the lowest for blends containing 40% PCR ( p0/ q0 ˜ 0.34). The vulcanized blends were characterized for solvent diffusion characteristics by following the swelling dynamics. Blends with higher PCR content showed anomalous swelling. The sorption and permeability of the solvent were not strictly in accordance with each other and the extent of variation in two parameters was found to be a function of blend composition. The Δ G values for solvent diffusion were in the range -2.97 to -9.58 kJ/mol and indicated thermodynamically favorable sorption for all blends. These results were corroborated by dynamic swelling, experimental as well as simulated profiles and have been explained on the basis of correlation between crosslinking density, diffusion kinetics, thermodynamic parameters and polymer-polymer interaction parameter.

  15. Diene Valepotriates from Valeriana glechomifolia Prevent Lipopolysaccharide-Induced Sickness and Depressive-Like Behavior in Mice

    PubMed Central

    Müller, Liz G.; Borsoi, Milene; Stolz, Eveline D.; Herzfeldt, Vivian; Viana, Alice F.; Ravazzolo, Ana Paula; Rates, Stela Maris K.

    2015-01-01

    Valeriana glechomifolia, a native species from southern Brazil, presents antidepressant-like activity and diene valepotriates (VAL) contribute to the pharmacological properties of the genus. It is known that depression can develop on an inflammation background in vulnerable patients and antidepressants present anti-inflammatory properties. We investigated the effects of VAL (10 mg/kg, p.o.) on sickness and depressive-like behaviors as well as proinflammatory cytokines (IL-1β and TNF-α) and BDNF expression in the cortex of mice exposed to a 5 min swimming session (as a stressful stimulus) 30 min before the E. coli LPS injection (600 µg/kg, i.p.). The forced swim + LPS induced sickness and depressive-like behaviors, increased the cortical expression of IL-1β and TNF-α, and decreased BDNF expression. VAL was orally administered to mice 1 h before (pretreatment) or 5 h after (posttreatment) E. coli LPS injection. The pretreatment with VAL restored the behavioral alterations and the expression of cortical proinflammatory cytokines in LPS-injected animals but had no effects on BDNF expression, while the posttreatment rescued only behavioral alterations. Our results demonstrate for the first time the positive effects of VAL in an experimental model of depression associated with inflammation, providing new data on the range of action of these molecules. PMID:26170871

  16. Metal Catalysis in Thiolation and Selenation Reactions of Alkynes Leading to Chalcogen‐Substituted Alkenes and Dienes

    PubMed Central

    2015-01-01

    Abstract This review covers recent achievements in metal‐catalyzed Z−H and Z−Z (Z=S, Se) bond addition to the triple bonds of alkynes—a convenient and atom‐efficient way to carbon‐element bond formation. Various catalytic systems (both homogeneous and heterogeneous) developed to date to obtain mono‐ and bis‐chalcogen‐substituted alkenes or dienes, as well as carbonyl compounds or heterocycles, starting from simple and available alkynes and chalcogenols or dichalcogenides are described. The right choice of metal and ligands allows us to perform these transformations with high selectivities under mild reaction conditions, thus tolerating unprotected functional groups in substrates and broadening ways of further modification of the products. The main aim of the review is to show the potential of the catalytic methods developed in synthetic organic chemistry. Thus, emphasis is made on the scope of reactions, types of products that can be selectively formed, convenience, and scalability of the catalytic procedures. A brief mechanistic description is also given to introduce new readers to the topic. PMID:27308193

  17. Structure Revision of (22E)-Ergosta-7,22-diene-3β,5α,6β,9α,14α- pentol from the Spores of the Medicinal Mushroom Ganoderma lucidum.

    PubMed

    Yaoita, Yasunori; Machida, Koichi

    2016-02-01

    Careful reexamination of the published ¹H and ¹³C NMR spectral data of (22E)-ergosta-7,22-diene-3β,5α,6β,9α,14α-pentol (1), isolated from the spores of the medicinal mushroom Ganoderma lucidum, indicates that, in reality, the compound is (22E)-ergosta-7,22-diene-3β,5α,6β,9α,14β-pentol (5). PMID:27032196

  18. Sulfur monoxide transfer from peri-substituted trisulfide-2-oxides to dienes: substituent effects, mechanistic studies and application in thiophene synthesis.

    PubMed

    Grainger, Richard S; Patel, Bhaven; Kariuki, Benson M; Male, Louise; Spencer, Neil

    2011-04-20

    Three peri-substituted trisulfide-2-oxides are prepared by treatment of 1,8-naphthalene dithiols with thionyl chloride and pyridine. The 1,2,3-trithiane-2-oxide ring adopts a sofa conformation in the solid state, with a pseudoaxial oxygen and evidence of ring strain (peri-interaction). Heating the trisulfide-2-oxides in the presence of a diene results in formal sulfur monoxide (SO) transfer to form unsaturated cyclic sulfoxides, along with a recyclable 1,8-naphthalene disulfide. The presence of o-methoxy or o-tert-butyl substituents on the naphthalene ring lowers the temperature and increases the rate at which SO transfer occurs. Trapping experiments and kinetic studies are consistent with the generation of triplet SO, followed by in situ trapping by diene. Transfer of SO also occurs upon irradiation at room temperature, but yields of sulfoxide are lower. Dehydration of the sulfoxides under Pummerer conditions gives thiophenes, including the naturally occurring thioperillene. Two dienes form thiophenes directly under the SO transfer conditions. The methodology is applied in a formal synthesis of the antiplatelet medication Plavix. PMID:21443185

  19. Theoretical investigation of the stereochemistry of the polymerization of. cap alpha. -olefins and dienes with the participation of Ziegler-Natta catalysts

    SciTech Connect

    Minsker, K.S.; Karpasas, M.M.

    1986-09-01

    The processes involved in the formation of the active polymerization sites in heterogeneous Ziegler-Natta catalysts have been investigated with consideration of the real structure of the components by the atom-atom potential method, the Monte-Carlo method, a modified diatomics-in-molecules method, and the CNDO/2 method with the aid of the available experimental facts. It has been shown that three types of bimetallic active sites (AS), which differ with respect to the spatial configuration of the coordination sphere, viz., AS-1, AS-2, and AS-3, form, depending on the electronic structure of the homogeneous component R /SUB n/ M, the ionic radius of M (M is a metal from groups I-III), and the unit-cell parameters of the heterogeneous component MeX /SUB m/ (Me is a transition metal from groups IV-VIII). Only the AS-1 sites are stereospecific in the polymerization of ..cap alpha..-olefins and 1,3-dienes (isotactic polyolefins and 1,4-trans-polydienes form); the AS-2 sites are nonstereospecific in the polymerization of ..cap alpha..-olefins, but they form stereoregular 1,4-cis-polydienes; the AS-3 sites are nonstereospecific in the polymerization of both ..cap alpha..-olefins and 1,3-dienes. The phenomenon of stereoregularization in the polymerization of ..cap alpha..-olefins and 1,3-dienes is determined by the steric and electrostatic factors.

  20. Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln==Sm, Eu, Gd) and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln==Tb, Dy, Ho)

    SciTech Connect

    Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian

    2013-10-15

    Solvothermal reactions of Ln{sub 2}O{sub 3}, As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln{sub 2}O{sub 3} oxides were converted to [Ln(dien){sub 2}]{sup 3+} complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS{sub 4} unit. In 1−3, the AsS{sub 4} units interconnect the [Ln(dien){sub 2}]{sup 3+} cations via Ln−S bonds as tridentate μ-1κ,2κ{sup 2}-AsS{sub 4} bridging ligands, resulting in the neutral coordination polymers [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln1). In 4−6, the AsS{sub 4} units coordinate with the Ln{sup 3+} ion of [Ln(dien){sub 2}]{sup 3+} as 1κ{sup 2}-AsS{sub 4} chelating ligands to form neutral coordination compounds [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln2). The Ln{sup 3+} ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln{sup 3+} ions. Optical absorption spectra showed that 1−6 have potential use as semiconductors with the band gaps in the range 2.18−3.21 eV. - Graphical abstract: Two types of Ln-thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] were prepared by solvothermal methods and the soft Lewis basic AsS{sub 4}{sup 3–} ligand to Ln(III) centers with polyamine co-ligand was obtained. Display Omitted - Highlights: • Lanthanide thioarsenates were prepared by solvothermal methods. • The soft Lewis basic AsS{sub 4} ligand coordinate Ln{sup 3+} ions with coexistence polyamine ligands. • Two structural types of Ln-thioarsenates with structural turnover at Tb were obtained along Ln series. • The Ln-thioarsenates are potential semiconductors

  1. Assessment of the role of in situ generated (E)-2,4-diene-valproic acid in the toxicity of valproic acid and (E)-2-ene-valproic acid in sandwich-cultured rat hepatocytes

    SciTech Connect

    Surendradoss, Jayakumar; Chang, Thomas K.H.; Abbott, Frank S.

    2012-11-01

    Valproic acid (VPA) undergoes cytochrome P450-mediated desaturation to form 4-ene-VPA, which subsequently yields (E)-2,4-diene-VPA by β-oxidation. Another biotransformation pathway involves β-oxidation of VPA to form (E)-2-ene-VPA, which also generates (E)-2,4-diene-VPA by cytochrome P450-mediated desaturation. Although the synthetic form of (E)-2,4-diene-VPA is more hepatotoxic than VPA as shown in various experimental models, there is no conclusive evidence to implicate the in situ generated (E)-2,4-diene-VPA in VPA hepatotoxicity. The present study investigated the effects of modulating the in situ formation of (E)-2,4-diene-VPA on markers of oxidative stress (formation of 2′,7′-dichlorofluorescein; DCF), steatosis (accumulation of BODIPY 558/568 C{sub 12}), necrosis (release of lactate dehydrogenase; LDH), and on cellular total glutathione (GSH) levels in sandwich-cultured rat hepatocytes treated with VPA or (E)-2-ene-VPA. Treatment with either of these chemicals alone increased each of the toxicity endpoints. In VPA-treated hepatocytes, (E)-2,4-diene-VPA was detected only at trace levels, even after phenobarbital (PB) pretreatment and there was no effect on the toxicity of VPA. Furthermore, pretreatment with a cytochrome P450 enzyme inhibitor, 1-aminobenzotriazole (1-ABT), did not influence the extent of VPA toxicity in both PB-pretreated and vehicle-pretreated hepatocytes. However, in (E)-2-ene-VPA-treated hepatocytes, PB pretreatment greatly enhanced the levels of (E)-2,4-diene-VPA and this was accompanied by a further enhancement of the effects of (E)-2-ene-VPA on DCF formation, BODIPY accumulation, LDH release, and GSH depletion. Pretreatment with 1-ABT reduced the concentrations of (E)-2,4-diene-VPA and the extent of (E)-2-ene-VPA toxicity; however, this occurred in PB-pretreated hepatocytes, but not in control hepatocytes. In conclusion, in situ generated (E)-2,4-diene-VPA is not responsible for the hepatocyte toxicity of VPA, whereas it

  2. The Labdane Ent-3-Acetoxy-Labda-8(17), 13-Dien-15-Oic Decreases Blood Pressure In Hypertensive Rats

    PubMed Central

    Simplicio, Janaina A.; Simão, Marilia R.; Ambrosio, Sergio R.; Tirapelli, Carlos R.

    2016-01-01

    Background Labdane-type diterpenes induce lower blood pressure via relaxation of vascular smooth muscle; however, there are no studies describing the effects of labdanes in hypertensive rats. Objective The present study was designed to investigate the cardiovascular actions of the labdane-type diterpene ent-3-acetoxy-labda-8(17), 13-dien-15-oic acid (labda-15-oic acid) in two-kidney 1 clip (2K-1C) renal hypertension. Methods Vascular reactivity experiments were performed in aortic rings isolated from 2K-1C and normotensive (2K) male Wistar rats. Nitrate/nitrite (NOx) measurement was performed in aortas by colorimetric assay. Blood pressure measurements were performed in conscious rats. Results Labda-15-oic acid (0.1-300 µmol/l) and forskolin (0.1 nmol/l - 1 µmol/l) relaxed endothelium-intact and endothelium-denuded aortas from both 2K-1C and 2K rats. Labda-15-oic acid was more effective at inducing relaxation in endothelium-intact aortas from 2K pre-contracted with phenylephrine when compared to the endothelium-denuded ones. Forskolin was more potent than labda-15-oic acid at inducing vascular relaxation in arteries from both 2K and 2K-1C rats. Labda-15-oic acid-induced increase in NOx levels was lower in arteries from 2K-1C rats when compared to 2K rats. Intravenous administration of labda-15-oic acid (0.3-3 mg/kg) or forskolin (0.1-1 mg/kg) induced hypotension in conscious 2K-1C and 2K rats. Conclusion The present findings show that labda-15-oic acid induces vascular relaxation and hypotension in hypertensive rats. PMID:27096521

  3. On the mechanism of the Di-. pi. -methane rearrangement of bicyclo(3. 2. 1)octa-2,6-diene: Deuterium labeling and generation of diradical intermediates via photolysis and thermolysis of appropriate azoalkanes

    SciTech Connect

    Adam, W.; Doerr, M. ); De Lucchi, O. )

    1989-07-05

    The direct (254 nm) and acetone-sensitized (300 nm) photolyses of 2,4,4-trideuteriobicyclo(3.2.1)octa-2,6-diene (D-1) gave exclusively 3,5,5-trideuteriotricyclo(4.2.0.0)oct-3-ene (D-7) and 2,6,6-trideuteriotricyclo(3.2.1.0)oct-3-ene (D-8) but no rearranged diene, namely, 2,8,8-trideuteriobicyclo(3.2.1)octa-2,6-diene (D-1{prime}). Pyrolysis (400{degree}C) and direct (334 nm) and benzophenone-sensitized (364 nm) photolyses of the azoalkane 3,5,5-trideuterio-9,10-diazatricyclo(4.4.0.0)deca-3,9-diene (D-9) afforded a mixture of tricyclooctenes D-7 (major product) and D-8 and bicyclooctadiene D-1, but no rearranged diene D-1{prime}. These three modes of denitrogenation of the azoalkane 2,2,7-trideuterio-4,5-diazatricyclo(4.3.1.0)deca-4,8-diene (D-10) led only to the tricyclooctene D-8 (major product) and equal amounts of the bicyclooctadienes D-1 and D-1{prime}. Distinct temperature profiles were observed in the product fingerprints of the direct photolysis (334 nm) of the azoalkanes 9 and 10. For both azoalkanes 9 and 10 the quantum yields of denitrogenation increased with rising temperature. In none of these transformations could bicyclo(3.3.0)octa-2,7-diene (2) be detected. These results imply that the di-{pi}-methane rearrangement of the bicyclooctadienes 1 (D-1) and the denitrogenations of the azoalkanes 9 (D-9) and 10 (D-10) are disjoint chemical events. The intervention of diazenyl diradicals (one-bond cleavage of the azoalkanes) is postulated to be responsible for this disparity. The intervention of cyclopropyldicarbinyl diradical 3 as bona fide reaction intermediate in the di-{pi}-methane rearrangement of bicyclooctadiene 1 is questioned.

  4. Ultraviolet photochemistry of buta-1,3- and buta-1,2-dienes: Laser spectroscopic absolute hydrogen atom quantum yield and translational energy distribution measurements

    SciTech Connect

    Hanf, A.; Volpp, H.-R.; Sharma, P.; Mittal, J. P.; Vatsa, R. K.

    2010-07-14

    Using pulsed H-atom Lyman-{alpha} laser-induced fluorescence spectroscopy along with a photolytic calibration approach, absolute H-atom product quantum yields of {phi}{sub H-b13d}=(0.32{+-}0.04) and {phi}{sub H-b12d}=(0.36{+-}0.04) were measured under collision-free conditions for the 193 nm gas-phase laser flash photolysis of buta-1,3- and buta-1,2-diene at room temperature, which demonstrate that nascent H-atom formation is of comparable importance for both parent molecules. Comparison of the available energy fraction, f{sub T-b13d}=(0.22{+-}0.03) and f{sub T-b12d}=(0.13{+-}0.01), released as H+C{sub 4}H{sub 5} product translational energy with results of impulsive and statistical energy partitioning modeling calculations indicates that for both, buta-1,3- and buta-1,2-diene, H-atom formation is preceded by internal conversion to the respective electronic ground state (S{sub 0}) potential energy surfaces. In addition, values of {sigma}{sub b-1,3-d-L{alpha}=}(3.5{+-}0.2)x10{sup -17} cm{sup 2} and {sigma}{sub b-1,2-d-L{alpha}=}(4.4{+-}0.2)x10{sup -17} cm{sup 2} for the previously unknown Lyman-{alpha} (121.6 nm) radiation photoabsorption cross sections of buta-1,3- and buta-1,2-diene in the gas-phase were determined.

  5. Bis(μ2-iso-propyl-imido-κ(2) N:N)bis-[(η(5)-cyclo-penta-dien-yl)(ethenolato-κO)titanium(IV)].

    PubMed

    Haehnel, Martin; Spannenberg, Anke; Rosenthal, Uwe

    2014-01-01

    The title dinuclear half-sandwich complex, [CpTi(OCH=CH2)(μ2-N-iPr)]2 (Cp = cyclo-penta-dien-yl; iPr = isopropyl), was ob-tained from the reaction of Cp2TiCl2, n-butyl-lithium and iso-propyl-amine in tetra-hydro-furan. Each Ti(IV) atom is coordinated by one Cp ligand, one vin-yloxy unit and two bridging imido groups in a strongly distorted tetra-hedral geometry. There are two half mol-ecules in the asymmetric unit, such that whole mol-ecules being generated by inversion symmetry. PMID:24526944

  6. Synthesis of 2-Aryl- and 2-Vinylpyrrolidines via Copper-Catalyzed Coupling of Styrenes and Dienes with Potassium β-Aminoethyl Trifluoroborates.

    PubMed

    Um, Chanchamnan; Chemler, Sherry R

    2016-05-20

    2-Arylpyrrolidines occur frequently in bioactive compounds, and thus, methods to access them from readily available reagents are valuable. We report a copper-catalyzed intermolecular carboamination of vinylarenes with potassium N-carbamoyl-β-aminoethyltrifluoroborates. The reaction occurs with terminal, 1,2-disubstituted, and 1,1-disubstituted vinylarenes bearing a number of functional groups. 1,3-Dienes are also good substrates, and their reactions give 2-vinylpyrrolidines. Radical clock mechanistic experiments are consistent with the presence of carbon radical intermediates and do not support participation of carbocations. PMID:27160334

  7. Theoretical study of free-radical-mediated 5-exo-trig cyclizations of chiral 3-substituted hepta-1,6-dienes.

    PubMed

    d'Antuono, Philippe; Fritsch, Alain; Ducasse, Laurent; Castet, Frédéric; James, Philippe; Landais, Yannick

    2006-03-16

    Free radical-mediated 5-exo-trig cyclizations of hepta-1,6-dienes incorporating allylsilane, alkyl and alkoxy analogues are modeled using correlated ab initio calculations. The structural, electronic and thermochemical properties of reactants, products and transition species involved in the key step of the radical cyclization process are analyzed and compared with those predicted by the Beckwith-Houk transition models. The product ratios are calculated from the Gibbs energy differences between the possible transition structures following the Curtin-Hammet principle and compared to experimental values. PMID:16526655

  8. Silver ion high pressure liquid chromatography provides unprecedented separation of sterols: application to the enzymatic formation of cholesta-5,8-dien-3 beta-ol.

    PubMed Central

    Ruan, B; Shey, J; Gerst, N; Wilson, W K; Schroepfer, G J

    1996-01-01

    We report that silver ion HPLC provides remarkable separations of C27 sterols differing only in the number or location of olefinic double bonds. This technique has been extended to LC-MS, analysis of purified components by GC, GC-MS, and 1H NMR, and to its use on a semipreparative scale. The application of this methodology for the demonstration of the catalysis, by rat liver microsomes, of the conversion of 7-dehydrocholesterol to cholesta-5,8-dien-3 beta-ol is also presented. PMID:8876182

  9. Brønsted Acid-Catalyzed Transfer Hydrogenation of Imines and Alkenes Using Cyclohexa-1,4-dienes as Dihydrogen Surrogates.

    PubMed

    Chatterjee, Indranil; Oestreich, Martin

    2016-05-20

    Cyclohexa-1,4-dienes are introduced to Brønsted acid-catalyzed transfer hydrogenation as an alternative to the widely used Hantzsch dihydropyridines. While these hydrocarbon-based dihydrogen surrogates do offer little advantage over established protocols in imine reduction as well as reductive amination, their use enables the previously unprecedented transfer hydrogenation of structurally and electronically unbiased 1,1-di- and trisubstituted alkenes. The mild procedure requires 5.0 mol % of Tf2NH, but the less acidic sulfonic acids TfOH and TsOH work equally well. PMID:27181437

  10. Chemistry of enol ethers. LXXXIV. Condensation of acetals of saturated aldehydes with 2-trimethylsilyloxy-1,3-dienes. Synthesis of /beta/-alkoxy-alkyl vinyl and divinyl ketones

    SciTech Connect

    Makin, S.M.; Nazarova, O.N.; Dymshakova, G.M.; Kundryutskova, L.A.

    1988-11-10

    The addition of the acetals of saturated aldehydes (formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and isobutyraldehyde) to 2-trimethylsilyloxy-4-methyl-1,3-pentadiene in the presence of aprotic acids (ZnCl/sub 2/, ZnBr/sub 2/, FeCl/sub 3/, SnCl/sub 4/, BF/sub 3/ /times/ OEt/sub 2/) takes place at positions 1, 2 of the diene system with the formation of /beta/-alkoxyalkyl vinyl ketones. The most effective catalysts of this reaction were stannic chloride and zinc bromide. The alkyl derivatives of divinyl ketones are formed when the obtained /beta/-alkoxyalkyl vinyl ketones are heated with p-toluenesulfonic acid.

  11. [Overexpressing 3-ketosteroid-Δ1-dehydrogenase for degrading phytosterols into androst-1,4-diene-3,17-dione].

    PubMed

    Zhang, Lele; Zhang, Xian; Shao, Minglong; Chen, Rongrong; Rao, Zhiming; Li, Hu; Xu, Zhenghong

    2015-11-01

    We constructed plasmid pMTac to overexpress 3-ketosteroid-Δ1-dehydrogenase (KSDD) in Mycobacterium neoaurum JC-12 for improving androst-1,4-diene-3,17-dione (ADD) production. To construct pMTac, pACE promoter on pMF41 was replaced by tac promoter, and then four recombinants were constructed, which were M. neoaurum JC-12/pMF41-gfp, M. neoaurum JC-12/pMTac-gfp, M. neoaurum JC-12/pMF41-ksdd and M. neoaurum JC-12/pMTac-ksdd. Fluorescence detection results show that much more green fluorescent protein (GFP) was expressed in M. neoaurum JC-12/pMTac-ksdd than M. neoaurum JC-12/pMF41-ksdd. The activity of KSDD was 2.41 U/mg in M. neoaurum JC-12/pMTac-ksdd, 6.53-fold as that of M. neoaurum JC-12 and 4.36-fold as that of M. neoaurum JC-12/pMF41-ksdd. In shake flask fermentation, ADD production of M. neoaurum JC-12/pMTac-ksdd was 5.94 g/L, increased about 22.2% compared to the original strain M. neoaurum JC-12 and 12.7% to M. neoaurum JC-12/pMF41-ksdd. AD (4-androstene-3,17-dione) production of JC-12/pMTac-ksdd was 0.17 g/L, decreased 81.5% compared to M. neoaurum JC-12 and 71.2% to M neoaurum JC-12/pMF41-ksdd. In the 5 L fermenter, 20 g/L phytosterols was used as substrate, ADD production of M. neoaurum JC-12/pMTac-ksdd was improved to 10.28 g/L. pMTac is favorable for expressing KSDD in M. neoaurum JC-12, and overexpression of KSDD has beneficial effect on ADD producing, and it is the highest level ever reported using fermentation method in M. neoaurum. PMID:26939442

  12. Expression of Delta(12) fatty acid desaturase during the induced accumulation of the antifungal diene in avocado fruits.

    PubMed

    Wang, Xuejun; Beno-Moualem, Delila; Kobiler, Ilana; Leikin-Frenkel, Alicia; Lichter, Amnon; Prusky, Dov

    2004-11-01

    SUMMARY The preformed (Z,Z)-1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene (AFD) is the most active antifungal compound in avocado; it affects the quiescence of Colletotrichum gloeosporioides in unripe fruit. One of the genes encoding Delta(12) fatty acid desaturase (avfad12) was hypothesized to take part in the biosynthesis of AFD, and its expression pattern and enzymatic activity were determined in relation to the content of AFD. Using avfad12-3 as a probe, high levels of expression were detected in young fruits and leaves, where the level of AFD was highest. In contrast, Northern analysis of RNA from mature leaves and fruits showed no transcripts from the avfad12 gene family and lower AFD content. The transcripts from the avfad12 gene family, the enzymatic activity of Delta(12) fatty acid desaturase, and the level of AFD in unripe-resistant fruits increased transiently when the fruits were inoculated with C. gloeosporioides or exposed to ethylene (40 microL/L), low temperature (4 degrees C) or 1 mm H(2)O(2), but ripe fruits were not affected. The effect of H(2)O(2) on the transcripts from the avfad12 gene family is of specific importance, because reactive oxygen species were produced by unripe-resistant host fruit soon after inoculation of C. gloeosporioides. In addition, the fungus itself produced H(2)O(2) in culture medium at pH 5.0, which is similar to the pH of unripe-resistant fruit, but not at pH 7.0. Treatments that enhanced Delta(12) fatty acid desaturase activity increased the concentration of the AFD precursor, linoleic acid, and its incorporation into AFD; these treatments also caused a delay in decay development. The present results demonstrate temporal relationships among the transcripts from the avfad12 gene family, the synthesis of the precursor of AFD (linoleic acid), the AFD content and quiescence of C. gloeosporioides in unripe fruits. PMID:20565631

  13. Reactivity Study of Pyridyl-Substituted 1-Metalla-2,5-diaza-cyclopenta-2,4-dienes of Group 4 Metallocenes.

    PubMed

    Becker, Lisanne; Reiß, Fabian; Altenburger, Kai; Spannenberg, Anke; Arndt, Perdita; Jiao, Haijun; Rosenthal, Uwe

    2016-07-25

    In this work the reactivity of 1-metalla-2,5-diaza-cyclopenta-2,4-dienes of group 4 metallocenes, especially of the pyridyl-substituted examples, towards small molecules is investigated. The addition of H2 , CO2 , Ph-C≡N, 2-py-C≡N, 1,3-dicyanobenzene or 2,6-dicyanopyridine results in exchange reactions, which are accompanied by the elimination of a nitrile. For CO2 , a coordination to the five-membered cycle occurs in case of Cp*2 Zr(N=C(2-py)-C(2-py)=N). A 1,4-diaza-buta-1,3-diene complex is formed by H-transfer in the conversion of the analogous titanocene compound with CH3 -C≡N, PhCH2 -C≡N or acetone. For CH3 -C≡N a coupling product of three acetonitrile molecules is established additionally. In order to split off the metallocene from the coupled nitriles, we examined reactions with HCl, PhPCl2 , PhPSCl2 and SOCl2 . In the last case, the respective thiadiazole oxides and the metallocene dichlorides were obtained. A subsequent reaction produced thiadiazoles. PMID:27312375

  14. Functional Identification of Valerena-1,10-diene Synthase, a Terpene Synthase Catalyzing a Unique Chemical Cascade in the Biosynthesis of Biologically Active Sesquiterpenes in Valeriana officinalis*

    PubMed Central

    Yeo, Yun-Soo; Nybo, S. Eric; Chittiboyina, Amar G.; Weerasooriya, Aruna D.; Wang, Yan-Hong; Góngora-Castillo, Elsa; Vaillancourt, Brieanne; Buell, C. Robin; DellaPenna, Dean; Celiz, Mary Dawn; Jones, A. Daniel; Wurtele, Eve Syrkin; Ransom, Nick; Dudareva, Natalia; Shaaban, Khaled A.; Tibrewal, Nidhi; Chandra, Suman; Smillie, Troy; Khan, Ikhlas A.; Coates, Robert M.; Watt, David S.; Chappell, Joe

    2013-01-01

    Valerian is an herbal preparation from the roots of Valeriana officinalis used as an anxiolytic and sedative and in the treatment of insomnia. The biological activities of valerian are attributed to valerenic acid and its putative biosynthetic precursor valerenadiene, sesquiterpenes, found in V. officinalis roots. These sesquiterpenes retain an isobutenyl side chain whose origin has been long recognized as enigmatic because a chemical rationalization for their biosynthesis has not been obvious. Using recently developed metabolomic and transcriptomic resources, we identified seven V. officinalis terpene synthase genes (VoTPSs), two that were functionally characterized as monoterpene synthases and three that preferred farnesyl diphosphate, the substrate for sesquiterpene synthases. The reaction products for two of the sesquiterpene synthases exhibiting root-specific expression were characterized by a combination of GC-MS and NMR in comparison to the terpenes accumulating in planta. VoTPS7 encodes for a synthase that biosynthesizes predominately germacrene C, whereas VoTPS1 catalyzes the conversion of farnesyl diphosphate to valerena-1,10-diene. Using a yeast expression system, specific labeled [13C]acetate, and NMR, we investigated the catalytic mechanism for VoTPS1 and provide evidence for the involvement of a caryophyllenyl carbocation, a cyclobutyl intermediate, in the biosynthesis of valerena-1,10-diene. We suggest a similar mechanism for the biosynthesis of several other biologically related isobutenyl-containing sesquiterpenes. PMID:23243312

  15. Functional Analysis of Amorpha-4,11-Diene Synthase (ADS) Homologs from Non-Artemisinin-Producing Artemisia Species: The Discovery of Novel Koidzumiol and (+)-α-Bisabolol Synthases.

    PubMed

    Muangphrom, Paskorn; Seki, Hikaru; Suzuki, Munenori; Komori, Aya; Nishiwaki, Mika; Mikawa, Ryota; Fukushima, Ery Odette; Muranaka, Toshiya

    2016-08-01

    The production of artemisinin, the most effective antimalarial compound, is limited to Artemisia annua. Enzymes involved in artemisinin biosynthesis include amorpha-4,11-diene synthase (ADS), amorpha-4,11-diene 12-monooxygenase (CYP71AV1) and artemisinic aldehyde Δ(11)13 reductase (DBR2). Although artemisinin and its specific intermediates are not detected in other Artemisia species, we reported previously that CYP71AV1 and DBR2 homologs were expressed in some non-artemisinin-producing Artemisia plants. These homologous enzymes showed similar functions to their counterparts in A. annua and can convert fed intermediates into the following products along the artemisinin biosynthesis in planta These findings suggested a partial artemisinin-producing ability in those species. In this study, we examined genes highly homologous to ADS, the first committed gene in the pathway, in 13 Artemisia species. We detected ADS homologs in A. absinthium, A. kurramensis and A. maritima. We analyzed the enzymatic functions of all of the ADS homologs after obtaining their cDNA. We found that the ADS homolog from A. absinthium exhibited novel activity in the cyclization of farnesyl pyrophosphate (FPP) to koidzumiol, a rare natural sesquiterpenoid. Those from A. kurramensis and A. maritima showed similar, but novel, activities in the cyclization of FPP to (+)-α-bisabolol. The unique functions of the novel sesquiterpene synthases highly homologous to ADS found in this study could provide insight into the molecular basis of the exceptional artemisinin-producing ability in A. annua. PMID:27273626

  16. Enantioselective Arylation of N-Tosylimines by Phenylboronic Acid Catalysed by a Rhodium/Diene Complex: Reaction Mechanism from Density Functional Theory.

    PubMed

    Sieffert, Nicolas; Boisson, Julien; Py, Sandrine

    2015-06-26

    A DFT study of the reaction mechanism of the rhodium-catalysed enantioselective arylation of (E)-N-propylidene-4-methyl-benzenesulfonamide by phenylboronic acid [Lin et al J. Am. Chem. Soc. 2011, 133, 12394] is reported. The catalyst ([{Rh(OH)(diene)}2]) includes a chiral diene ligand and the reaction is conducted in 1,4-dioxane in the presence of drying agents (4 Å molecular sieves). Because phenylboronic acid is in equilibrium with phenylboroxin and water under the reaction conditions, three catalytic cycles are proposed that differ in the way the transmetallation and the release of the product are brought about, depending on the availability of phenylboronic acid, water and boroxin in the reaction medium. Based on computations, a new mechanism for the title reaction is proposed, in which phenylboronic acid plays the double role of "aryl source" and proton donor. This path does not require the presence of adventitious water molecules, in keeping with a reaction conducted in a dry medium. Comparisons with the generally accepted mechanism for arylation of enones proposed by Hayashi and co-workers (J. Am. Chem. Soc. 2002, 124, 5052) show that the latter mechanism is less favourable and is not expected to operate in the case of the N-tosylimine substrate considered herein. Finally, the possibility that phenylboroxin is the aryl source has also been investigated, but is not found to be competitive. PMID:26032123

  17. Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

    SciTech Connect

    Zhao Jing; Liang Jingjing; Pan Yingli; Zhang Yong; Jia Dingxian

    2011-06-15

    Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en){sub 2}(dien)({eta}{sup 2}-SbSe{sub 4})] (Ln=Ce(1a), Nd(1b)), [Ln(en){sub 2}(dien)(SbSe{sub 4})] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)({mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4})]{sub {infinity}} (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)({eta}{sup 2}-SbSe{sub 4})] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe{sub 4}]{sup 3-} acts as a monodentate ligand mono-SbSe{sub 4}, a bidentate chelating ligand {eta}{sup 2}-SbSe{sub 4} or a tridentate bridging ligand {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} to the lanthanide(III) center depending on the Ln{sup 3+} ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E{sub g} between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: > Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. > The [SbSe{sub 4}]{sup 3-} anion acts as a mono-SbSe{sub 4}, a {eta}{sup 2}-SbSe{sub 4} or a {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} ligand to the Ln{sup 3+} ions. > The soft base ligand [SbSe{sub 4}]{sup 3-} can be controlled to coordinate to the Ln{sup 3+} ions with en+dien and en+trien as co-ligands.

  18. Thermoplastic vulcanizate nanocomposites based on polypropylene/ethylene propylene diene terpolymer (PP/EPDM) prepared by reactive extrusion

    NASA Astrophysics Data System (ADS)

    Mirzadeh, Amin

    using the solvent extraction and gravimetry technique. Additionally, the effect of continuity on rheological behaviour of TPE nanocomposites was investigated. The ultimate goal in this field is to maximize the rubber like behaviour by controlling the blend morphology and the level of crosslinking. Therefore, this study also covers the effects of nanoclay presence and its dispersion level on the crosslinking reaction of thermoplastic vulcanizate nanocomposites prepared by reactive extrusion. Here, the rubber phase was dynamically vulcanized using dimethylol phenolic resin or octylphenol-formaldehyde resin along with stannous chloride dihydrate as the catalyst. In the present study, the dynamic vulcanization of the prepared TPVs and corresponding nanocomposites are characterized using different criteria, such as gel content, viscosity and normalized storage modulus in the time sweep tests, nuclear magnetic resonance (NMR) signal line width, bound curative content and residual diene concentration. The combination of the above parameters appears to be sufficient to provide a clear description of the systems. The last part of the present study is devoted to find how the dispersion level of nanoclay and consequently the extent of crosslinking change the rubber like behaviour and the morphology of the prepared TPVs. Therefore, recently developed method named temperature scanning stress relaxation (TSSR) was used to estimate the rubber indices of TPVs and TPV nanocomposites. The mentioned method also successfully provided information about the extent of crosslinking reaction. It is shown that the rubber like behaviour of the blends containing 50wt% and 60wt% of EPDM in which morphological studies suggest the presence of the rubber droplets in vicinity of irregular shape rubber particles with a low level of interconnectivity, correlates with the rubber droplet size. Therefore, the nanoclay presence affects the rubber index values mainly through its effect on the size of the

  19. Metalloporphyrin-Based Hypercrosslinked Polymers Catalyze Hetero-Diels-Alder Reactions of Unactivated Aldehydes with Simple Dienes: A Fascinating Strategy for the Construction of Heterogeneous Catalysts.

    PubMed

    Dou, Zhiyu; Xu, Li; Zhi, Yongfeng; Zhang, Yuwei; Xia, Hong; Mu, Ying; Liu, Xiaoming

    2016-07-11

    We describe a novel and intriguing strategy for the construction of efficient heterogeneous catalysts by hypercrosslinking catalyst molecules in a one-pot Friedel-Crafts alkylation reaction. The new hypercrosslinked polymers (HCPs) as porous solid catalysts exhibit the combined advantages of homogeneous and heterogeneous catalysis, owing to their high surface area, good stability, and tailoring of catalytic centers on the frameworks. Indeed, a new class of metalloporphyrin-based HCPs were successfully synthesized using modified iron(III) porphyrin complexes as building blocks, and the resulting networks were found to be excellent recyclable heterogeneous catalysts for the hetero-Diels-Alder reaction of unactivated aldehydes with 1,3-dienes. Moreover, this new strategy showed wide adaptability, and many kinds of homogeneous-like solid-based catalysts with high catalytic performance and excellent recyclability were also constructed. PMID:27147500

  20. Intense Ground-State Charge-Transfer Interactions in Low-Bandgap, Panchromatic Phthalocyanine-Tetracyanobuta-1,3-diene Conjugates.

    PubMed

    Sekita, Michael; Ballesteros, Beatriz; Diederich, François; Guldi, Dirk M; Bottari, Giovanni; Torres, Tomás

    2016-04-25

    A cycloaddition-retroelectrocyclization reaction between tetracyanoethylene and two zinc phthalocyanines (Zn(II) Pcs) bearing one or four anilino-substituted alkynes has been used to install a strong, electron-accepting tetracyanobuta-1,3-diene (TCBD) between the electron-rich Zn(II) Pc and aniline moieties. A combination of photophysical, electrochemical, and spectroelectrochemical investigations with the Zn(II) Pc-TCBD-aniline conjugates, which present panchromatic absorptions in the visible region extending all the way to the near infrared, show that the formal replacement of the triple bond by TCBD has a dramatic effect on their ground- and excited-state features. In particular, the formation of extremely intense, ground-state charge-transfer interactions between Zn(II) Pc and the electron-accepting TCBD were observed, something unprecedented not only in Pc chemistry but also in TCBD-based porphyrinoid systems. PMID:27010677

  1. Neolignans with a Rare 2-Oxaspiro[4.5]deca-6,9-dien-8-one Motif from the Stem Bark of Cinnamomum subavenium.

    PubMed

    Lai, Yongji; Liu, Tingting; Sa, Rongjian; Wei, Xialan; Xue, Yongbo; Wu, Zhaodi; Luo, Zengwei; Xiang, Ming; Zhang, Yonghui; Yao, Guangmin

    2015-07-24

    Two pairs of racemic spirodienone neolignans with a rare 2-oxaspiro[4.5]deca-6,9-dien-8-one motif, named (±)-subaveniumins A (1) and B (2), were isolated from the bark of Cinnamomum subavenium. The chiral separation of the (+)-1, (-)-1, (+)-2, and (-)-2 enantiomers was accomplished via high-performance liquid chromatography on a chiral column. Their structures were elucidated using single-crystal X-ray diffraction and spectroscopic analyses (UV, IR, HRESIMS, and 1D and 2D NMR). The absolute configurations of the enantiomers were determined by comparing the experimental and calculated electronic circular dichroic spectra. The (+)-1, (-)-1, (+)-2, and (-)-2 enantiomers exhibited moderate inhibitory effects against NO production in RAW264.7 mouse macrophages induced by lipopolysaccharide, with IC50 values of 17.9, 5.6, 15.1, and 4.3 μM, respectively. PMID:26087384

  2. A New Series of Complexes Possessing Rare “Tertiary” Sulfonamide Nitrogen-to-Metal Bonds of Normal Length: fac-[Re(CO)3(N(SO2R)dien)]PF6 Complexes with Hydrophilic Sulfonamide Ligands

    PubMed Central

    Abhayawardhana, Pramuditha L.; Marzilli, Patricia A.; Fronczek, Frank R.

    2014-01-01

    Tertiary sulfonamide nitrogen-to-metal bonds of normal length are very rare. We recently discovered such a bond in one class of fac-[Re(CO)3(N(SO2R)(CH2Z)2)]n complexes (Z = 2-pyridyl) with N(SO2R)dpa ligands derived from di-(2-picolyl)amine (N(H)dpa). fac-[M(CO)3(N(SO2R)(CH2Z)2)]n agents (M = 186/188Re, 99mTc) could find use as radiopharmaceutical bioconjugates when R is a targeting moiety. However, the planar, electron-withdrawing 2-pyridyl groups of N(SO2R)dpa destabilize the ligand to base and create relatively rigid chelate rings, raising the possibility that the rare M– N(sulfonamide) bond is an artifact of a restricted geometry. Also, the hydrophobic 2-pyridyl groups could cause undesirable accumulation in the liver, limiting future use in radiopharmaceuticals. Our goal is to identify a robust, hydrophilic, and flexible N(CH2Z)2 chelate framework. New C2-symmetric ligands, N(SO2R)(CH2Z)2 with (Z = CH2NH2; R = Me, dmb, or tol), were prepared by treating N(H)dien(Boc)2, a protected diethylenetriamine (N(H)dien) derivative, with methanesulfonyl chloride (MeSO2Cl), 3,5-dimethylbenzenesulfonyl chloride (dmbSO2Cl), and 4-methylbenzenesulfonyl chloride (tolSO2Cl). Treatment of fac-[Re(CO)3(H2O)3]+ with these ligands, designated as N(SO2R)dien, afforded new fac-[Re(CO)3(N(SO2R)dien)]PF6 complexes. Comparing the fac-[Re(CO)3(N(SO2Me)dien)]PF6 and fac-[Re(CO)3(N(SO2Me)dpa)]PF6 complexes, we find that the ReI–N(sulfonamide) bonds are normal in length and statistically identical and that the methyl 13C NMR signal has an unusually upfield shift compared to that in the free ligand. We attribute this unusual upfield shift to the fact that the sulfonamide N undergoes an sp2-to-sp3 rehybridization upon coordination to ReI in both complexes. Thus, the sulfonamide N of N(SO2R)dien ligands is a good donor, even though the chelate rings are conformationally flexible. Addition of the strongly basic and potentially monodentate ligand, 4-dimethylaminopyridine, did not affect

  3. Crystal structure of 4,4-di-bromo-1-(3,4-di-meth-oxy-phen-yl)-2-aza-buta-1,3-diene-1-carbo-nitrile.

    PubMed

    Chaabene, Marwa; Khatyr, Abderrahim; Knorr, Michael; Askri, Moheddine; Rousselin, Yoann; Kubicki, Marek M

    2016-08-01

    The title compound, C12H10Br2N2O2, represents an example of a planar π-con-jugated 2-aza-butadiene mol-ecule, which is both an inter-esting starting material for further organic transformations and a potential ligand in organometallic coordination chemistry. Its metric mol-ecular parameters are typical for the family of 2-aza-buta-1,3-dienes not substituted at the (CH) 3-position. In the crystal, the almost planar (r.m.s. deviation = 0.0658 Å) aza-diene mol-ecules form one-dimensional double-wide ribbons through inter-molecular halogen bonds (C-Br⋯O and C-Br⋯Br-C), which then stack in a slipped manner through weak C-H⋯Br and π-π inter-actions to generate a three-dimensional network. PMID:27536405

  4. Enhanced Production of Androst-1,4-Diene-3,17-Dione by Mycobacterium neoaurum JC-12 Using Three-Stage Fermentation Strategy

    PubMed Central

    Shao, Minglong; Zhang, Xian; Rao, Zhiming; Xu, Meijuan; Yang, Taowei; Li, Hui; Xu, Zhenghong

    2015-01-01

    To improve the androst-1,4-diene-3,17-dione (ADD) production from phytosterol by Mycobacterium neoaurum JC-12, fructose was firstly found favorable as the initial carbon source to increase the biomass and eliminate the lag phase of M. neoaurum JC-12 in the phytosterol transformation process. Based on this phenomenon, two-stage fermentation by using fructose as the initial carbon source and feeding glucose to maintain strain metabolism was designed. By applying this strategy, the fermentation duration was decreased from 168 h to 120 h with the ADD productivity increased from 0.071 g/(L·h) to 0.108 g/(L·h). Further, three-stage fermentation by adding phytosterol to improve ADD production at the end of the two-stage fermentation was carried out and the final ADD production reached 18.6 g/L, which is the highest reported ADD production using phytosterol as substrate. Thus, this strategy provides a possible way in enhancing the ADD production in pharmaceutical industry. PMID:26352898

  5. Growth and characterization of a new organic nonlinear optical crystal: 1-(3-Nitrophenyl)-5-phenylpenta-2,4-dien-1-one

    NASA Astrophysics Data System (ADS)

    Patil, P. S.; Kumar, P. Ajay; Venugopal Rao, S.; Bhagavannarayana, G.

    2015-08-01

    Organic nonlinear optical single crystal of 1-(3-Nitrophenyl)-5-phenylpenta-2,4-dien-1-one (Ci3NC) with dimensions 25×15×10 mm3 was successfully grown for the first time by the slow evaporation solution growth technique (SEST). The structural perfection of the grown crystals has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements, and it was found that the crystalline perfection is reasonably good having very low angle (tilt angle ≤1‧) internal structural grain boundary. Thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. Powder test with Nd:YAG laser radiation shows second harmonic generation which is about 7 times that of urea. The optical transmittance window and the lower cutoff wavelength of the Ci3NC have been identified by UV-vis-NIR studies. Third-order nonlinear optical (NLO) response of Ci3NC has been examined using Z-scan technique with femtosecond (fs), MHz pulses at wavelengths of 870 nm and 900 nm. Various NLO coefficients such as two-photon absorption (2PA) coefficient (β), three photon absorption (3PA) coefficient (γ), and nonlinear refractive index (η2) were evaluated.

  6. In situ reactive compatibilization of polypropylene/ethylene-propylene-diene monomer thermoplastic vulcanizate by zinc dimethacrylate via peroxide-induced dynamic vulcanization.

    PubMed

    Chen, Yukun; Xu, Chuanhui; Liang, Xingquan; Cao, Liming

    2013-09-12

    This work demonstrates an approach of in situ reactive compatibilization between polypropylene (PP) and ethylene-propylene-diene monomer (EPDM) by using zinc dimethacrylate (ZDMA) as a compatibilizer and, simultaneously, as a very strong reinforcing agent. With the incorporation of 7phr ZDMA in the PP/EPDM (30/70, w/w) thermoplastic vulcanizate (TPV), the tensile strength, tear strength, elongation at break, and hardness of PP/EPDM/ZDMA TPV were increased from 5.3 MPa, 31.3 kN/m, 222%, and 78 up to 11.2 MPa, 64.2 kN/m, 396%, and 83, respectively. This tremendous reinforcing as well as the compatibilization effect of the ZDMA was understood by polymerization of ZDMA and ZDMA reacted with EPDM and PP during peroxide-induced dynamic vulcanization. A peculiar phase structure that rubber particles were surrounded and "bonded" by a thick transition zone that contained numerous of nanoparticles with dimensions of about 20-30 nm was observed from transmission electron microscopy. Scanning electron microscopy results confirmed that incorporation of ZDMA reduced the size of the cross-linked EPDM particles. Moreover, we found that the compatibilized TPV showed a higher tan δ peak temperature for EPDM phase and a lower tan δ peak temperature for PP phase. The suggested method for in situ reactive compatibilization of PP and EPDM offers routes to the design of new TPV-based technical products for diversified applications. PMID:23981036

  7. Morphology study of peroxide-induced dynamically vulcanized polypropylene/ethylene-propylene-diene monomer/zinc dimethacrylate blends during tensile deformation.

    PubMed

    Chen, Yukun; Xu, Chuanhui; Cao, Liming; Wang, Yanpeng; Fang, Liming

    2013-06-27

    Polypropylene (PP)/ethylene-propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blend (EPDM/PP ratio of 30/70) with remarkable extensibility was successfully prepared via peroxide dynamic vulcanization. The uniaxial tensile properties, crystallization behavior, structure, and morphology during stretching were investigated. The tensile process study showed that the PP/EPDM/ZDMA blend exhibited the rubbery-like behavior with an elongation beyond 600%. The ZDMA graft-product domain increased the compatibility and interfacial adhesion between rubber and PP phases, while it reduced the crystallinity of the PP phase. On the basis of TEM and SEM analyses, we found that the cross-linked rubber particles could be elongated and oriented along the tensile direction, whereas the ZDMA graft-product domain "encapsulated" rubber phase together, acting as a "bridge" between elongated rubber phases and the PP phase during uniaxial stretching. The stress could be effectively transferred from the PP phase to the numerous elongated rubber phases due to the excellent compatibility and interfacial adhesion between rubber and PP phases, resulting in the rubbery-like behavior. PMID:23742700

  8. endo/exo stereoselectivity in Diels-Alder reactions of α,β-dialkylated conjugated enals to cyclic 1,3-dienes: intermediates in the synthesis of (-)-β-santalol and its analogs.

    PubMed

    Chapuis, Christian; Skuy, David; de Saint Laumer, Jean-Yves; Brauchli, Robert

    2014-10-01

    Highly exo-selective [4+2] cycloadditions of cyclopenta-1,3-diene 2a to α,β-dialkyl conjugated enals 5 are compared with the analogous endo-favored Diels-Alder reaction of cyclohexa-1,3-diene 7. The exo-stereoselectivity is lower in the homologous case of methylcyclopenta-1,3-diene 9. This diastereoselectivity is discussed either in terms of a retro-homo-Diels-Alder reaction, associated with thermodynamic control, or with respect to either a competing hetero-Diels-Alder/Claisen or Cope domino pathway, or retro-Claisen/retro-hetero-Diels-Alder of the endo-homo-cycloadducts. These hypothetical mechanisms have been examined by DFT calculations at the MPW1K(CH2 Cl2 )/6-31+G** level of theory for the AlCl3 -mediated cycloadditions of 5d to 2a and 7. Application of Corey's methodology to the γ-halogeno-α-methyl-substituted dienophiles 5a and 5b allowed an enantioselective preparation of known and useful intermediates for the synthesis of either the naturally occurring (-)-β-santalol or its potentially olfactive structural analogs. PMID:25329781

  9. Dual Regulation of Cell Death and Cell Survival upon Induction of Cellular Stress by Isopimara-7,15-Dien-19-Oic Acid in Cervical Cancer, HeLa Cells In vitro

    PubMed Central

    Abu, Nadiah; Yeap, Swee K.; Pauzi, Ahmad Z. Mat; Akhtar, M. Nadeem; Zamberi, Nur R.; Ismail, Jamil; Zareen, Seema; Alitheen, Noorjahan B.

    2016-01-01

    The Fritillaria imperialis is an ornamental flower that can be found in various parts of the world including Iraq, Afghanistan, Pakistan, and the Himalayas. The use of this plant as traditional remedy is widely known. This study aims to unveil the anti-cancer potentials of Isopimara-7,15-Dien-19-Oic Acid, extracted from the bulbs of F. imperialis in cervical cancer cell line, HeLa cells. Flow cytometry analysis of cell death, gene expression analysis via cDNA microarray and protein array were performed. Based on the results, Isopimara-7,15-Dien-19-Oic acid simultaneously induced cell death and promoted cell survival. The execution of apoptosis was apparent based on the flow cytometry results and regulation of both pro and anti-apoptotic genes. Additionally, the regulation of anti-oxidant genes were up-regulated especially thioredoxin, glutathione and superoxide dismutase- related genes. Moreover, the treatment also induced the activation of pro-survival heat shock proteins. Collectively, Isopimara-7,15-Dien-19-Oic Acid managed to induce cellular stress in HeLa cells and activate several anti- and pro survival pathways. PMID:27065873

  10. Heats of formation of [2.2]paracyclophane-1-ene and [2.2]paracyclophane-1,9-diene - an experimental study.

    PubMed

    de Meijere, Armin; Kozhushkov, Sergei I; Rauch, Karsten; Schill, Heiko; Verevkin, Sergey P; Kümmerlin, Martin; Beckhaus, Hans-Dieter; Rüchardt, Christoph; Yufit, Dmitrii S

    2003-12-10

    The enthalpies of formation [Delta(g)] of tricyclo[8.2.2.2(4,7)]hexadeca-1(13),2,4(16),5,7(15),10(14),11-heptaene (2, 1,2-dehydro[2.2]paracyclophane or [2.2]paracyclophane-1-ene) and tricyclo[8.2.2.2(4,7)]hexadeca-1(13),2,4(16),5,7(15),8,10(14),11-octaene (3, 1,2,9,10-dehydro[2.2]paracyclophane or [2.2]paracyclophane-1,9-diene) have been determined by measuring their heats of combustion in a microcalorimeter and their heats of sublimation by the transpiration method. Values of the strain energies (SE) [SE(2) = 34.7 kcal mol(-)(1), SE(3) = 42.0 kcal mol(-)(1)] have been derived from the gas-phase heats of formation and are compared with those from MM3 and PM3 calculations and with the corresponding value SE(1) = 30.1 kcal mol(-)(1) for the parent tricyclo[8.2.2.2(4,7)]hexadeca-1(13),4(16),5,7(15),10(14),11-hexaene (1, [2.2]paracyclophane). The higher strain energies of 2 and 3 (by 4.6 and 11.9 kcal mol(-)(1)) are in accord with the well-known increased reactivities of their aromatic rings as a consequence of their increased bending. As revealed by an X-ray crystal structure analysis, the bending in the monoene 2 corresponds to that of 1 and 3 at one of two bridging corners. PMID:14653746

  11. Protection of HepG2 cells against acrolein toxicity by 2-cyano-3,12-dioxooleana-1,9-dien-28-imidazolide via glutathione-mediated mechanism.

    PubMed

    Shah, Halley; Speen, Adam M; Saunders, Christina; Brooke, Elizabeth A S; Nallasamy, Palanisamy; Zhu, Hong; Li, Y Robert; Jia, Zhenquan

    2015-10-01

    Acrolein is an environmental toxicant, mainly found in smoke released from incomplete combustion of organic matter. Several studies showed that exposure to acrolein can lead to liver damage. The mechanisms involved in acrolein-induced hepatocellular toxicity, however, are not completely understood. This study examined the cytotoxic mechanisms of acrolein on HepG2 cells. Acrolein at pathophysiological concentrations was shown to cause apoptotic cell death and an increase in levels of protein carbonyl and thiobarbituric acid reactive acid substances. Acrolein also rapidly depleted intracellular glutathione (GSH), GSH-linked glutathione-S-transferases, and aldose reductase, three critical cellular defenses that detoxify reactive aldehydes. Results further showed that depletion of cellular GSH by acrolein preceded the loss of cell viability. To further determine the role of cellular GSH in acrolein-mediated cytotoxicity, buthionine sulfoximine (BSO) was used to inhibit cellular GSH biosynthesis. It was observed that depletion of cellular GSH by BSO led to a marked potentiation of acrolein-mediated cytotoxicity in HepG2 cells. To further assess the contribution of these events to acrolein-induced cytotoxicity, triterpenoid compound 2-cyano-3,12-dioxooleana-1,9-dien-28-imidazolide (CDDO-Im) was used for induction of GSH. Induction of GSH by CDDO-Im afforded cytoprotection against acrolein toxicity in HepG2 cells. Furthermore, BSO significantly inhibited CDDO-Im-mediated induction in cellular GSH levels and also reversed cytoprotective effects of CDDO-Im in HepG2 cells. These results suggest that GSH is a predominant mechanism underlying acrolein-induced cytotoxicity as well as CDDO-Im-mediated cytoprotection. This study may provide understanding on the molecular action of acrolein which may be important to develop novel strategies for the prevention of acrolein-mediated toxicity. PMID:25504014

  12. Phase I Study of the Synthetic Triterpenoid, 2-Cyano-3, 12-Dioxoolean-1, 9-Dien-28-Oic Acid (CDDO), in Advanced Solid Tumors

    PubMed Central

    Speranza, Giovanna; Gutierrez, Martin E.; Kummar, Shivaani; Parker, Robert J.; Collins, Jerry; Yu, Yunkai; Cao, Liang; Murgo, Anthony J.; Doroshow, James H.; Chen, Alice

    2015-01-01

    Background The triterpenoid 2-Cyano-3, 12-Dioxoolean-1, 9-Dien-28-Oic Acid (CDDO, previously RTA-401) is a multifunctional molecule that controls cellular growth and differentiation. It is capable of activating the transcription factor peroxisome proliferator activator receptor-γ (PPARγ) and inducing apoptosis in malignant cells in vitro and in vivo. We conducted a phase I dose-escalation study to determine the toxicity, the maximum tolerated dose, and the pharmacokinetics and pharmacodynamics of CDDO, administered as a 5-day continuous infusion every 28 days in patients with advanced cancers. Methods An accelerated titration design was followed, with one patient per cohort entered, and doses ranging from 0.6 mg/m2/hr to 38.4 mg/m2/hr. Pharmacokinetics of CDDO was assessed and cleaved poly (ADP-ribose) polymerase (c-PARP), as a marker of apoptosis, was measured in peripheral blood mononuclear cells to assess drug effect. Results Seven patients, one patient per dose level up to dose level 7 (38.4 mg/m2/hr), were enrolled and received a total of 11 courses of treatment. Cmax increased proportionally with dose. Preclinically determined efficacious blood level (1 μM) of drug was attained at the highest dose level. One patient, at dose level 6, experienced grade 2 mucositis, nausea, vomiting, and anorexia. Four patients, on different dose levels, developed thromboembolic events subsequently considered as dose-limiting toxicity. No anti-tumor activity was noted. Conclusion A causal relationship of observed thromboembolic events to CDDO was considered possible but could not be established. Because of the adverse events and the development of an orally bioavailable derivative compound, CDDO methyl ester, this trial was terminated. PMID:21805353

  13. Postnatal decline in gonadal secretion of dehydroepiandrosterone and 3 beta-hydroxyandrosta-5,7-dien-17-one in the newborn foal.

    PubMed

    Raeside, J I; Renaud, R L; Christie, H L

    1997-11-01

    Dehydroepiandrosterone (DHEA) and 3 beta-hydroxyandrosta-5,7-dien-17-one (7-dehydro-DHEA) are secreted in large quantities by the remarkably hypertrophied fetal gonads of both sexes in the pregnant mare. Their secretion serves as the fetal component of a feto-placental unit for oestrogen production in equine pregnancies. They are secreted in large amounts but show a decline in late pregnancy when the fetal gonads regress and levels of oestrogens in the mare fall as a consequence. We have examined the levels of these precursor steroids in the newborn foal in the first days after birth. DHEA and 7-dehydro-DHEA were measured in peripheral plasma in a direct RIA with a DHEA antibody which cross-reacts with 7-dehydro DHEA (> 150%). Subsequent studies were performed with solid-phase extraction, separation of unconjugated from conjugated steroids, and HPLC fractionation followed by RIA. Detection on HPLC at 254 and 280 nm was compared with results from RIA. It was concluded that DHEA is the major steroid produced by the gonads at birth. The concentrations are highly variable in the first day of postnatal life (70.45 +/- 63.06 ng/ml, n = 52) and decline rapidly to < 2 ng/ml (n = 6) at 96 h after birth. At this time the sulphate form is also seen, with an increasing ratio of DHEAS/DHEA as the value for total DHEA falls. The mechanism and significance of the apparent abrupt decline in gonadal steroidogenesis in the newborn foal remain unknown. PMID:9415062

  14. HDL derived from the different phases of conjugated diene formation reduces membrane fluidity and contributes to a decrease in free cholesterol efflux from human THP-1 macrophages.

    PubMed

    Girona, Josefa; LaVille, Agnes E; Solà, Rosa; Motta, Claude; Masana, Lluís

    2003-09-22

    Oxidized HDL (ox-HDL) has been reported to reduce free cholesterol efflux from cells. In this study we investigate the effect of different stages of ox-HDL on macrophage membrane fluidity and its effect on free cholesterol efflux from macrophages as a cell function influenced by ox-HDL. HDL was oxidized by means of conjugated diene production using copper as a prooxidant. Fluidity of HDL and human THP-1 macrophage membranes was evaluated by changes in fluorescence anisotropy (r) by DPH probe where lower (r) values give higher fluidity. We found that ox-HDL derived from the propagation phase (PP-HDL) and the decomposition phase (DP-HDL) became less fluid ((r): 0.263+/-0.001, 0.279+/-0.002, respectively) than HDL from the lag phase (LP-HDL) and native HDL (nat-HDL) ((r): 0.206+/-0.001) (P<0.05). Macrophages incubated with PP-HDL and DP-HDL had less fluid membranes ((r): 0.231+/-0.001, 0.243+/-0.002, respectively) than those incubated with LP-HDL and nat-HDL ((r): 0.223+/-0.001) (P<0.05). Consequently, fluidity was reduced not only in ox-HDL but also in the cell membranes exposed to ox-HDL. A significant negative correlation was observed between macrophage membrane fluorescence anisotropy (r) and free cholesterol efflux from these cells (-0.876; P<0.05). Thus, lower membrane fluidity was associated with lower free cholesterol efflux from cells. In conclusion, the increase in the HDL oxidation process leads to a lost of macrophage membrane fluidity that could contribute to an explanation of the reduction of free cholesterol efflux from cells by ox-HDL. PMID:14499733

  15. Administration d’anti-inflammatoires non stéroïdiens aux enfants ayant des antécédents de sibilance

    PubMed Central

    Sih, Kendra; Goldman, Ran D.

    2016-01-01

    Résumé Question Un enfant qui fréquente ma clinique s’est récemment fait une entorse à la cheville et il éprouve de la douleur et de la difficulté à supporter son poids sur la jambe affectée. Sa mère lui donne de l’acétaminophène parce qu’on lui a dit de ne jamais utiliser d’anti-inflammatoires non stéroïdiens (AINS) en raison de son asthme contrôlé par pharmacologie. L’asthme chez un enfant est-il une contre-indication à l’administration d’AINS? La maladie respiratoire exacerbée par les AINS existe-t-elle comme entité réelle? Réponse Les AINS sont des médicaments analgésiques et antipyrétiques efficaces. La maladie respiratoire exacerbée par des AINS a été décrite chez des adultes ayant certains facteurs de prédisposition, mais n’a pas été clairement identifiée chez un grand nombre d’enfants. Les AINS peuvent donc être recommandés aux enfants ayant une sibilance connue qui n’ont pas d’antécédents de maladie respiratoire déclenchée par des AINS. PMID:27521406

  16. An ab initio study of relationships between bond lengths and the harmonic and anharmonic cross-coupling constants involving the double bonds in hetero-atom substituted conjugated dienes

    NASA Astrophysics Data System (ADS)

    Bock, Charles W.; Trachtman, Mendel; George, Philip

    1982-12-01

    The lengths of the terminal double bonds and the central CC single bond, and the cross-coupling constant involving the double bonds, calculated ab initio using the unscaled 4-31G basis set, are reported for 15 planar conformers of conjugated dienes containing the OCC'C″ grouping, 9 planar conformers containing the OCC'N grouping, and 6 planar conformers containing the OCC'O'grouping. The larger values for the CC bond length tend to be associated with the smaller values for the double-bond lengths, and vice versa. A linear relationship holds fairly well between rcc and the sum of the double-bond lengths. The sign of the cross-coupling constant is the same for each type of conjugated diene, negative for foc.c'c″ and foc.c'N' but positive for foc.c'o'. The values of foc.c'c″ and f oc.c'N are larger the smaller rcc' in accord with a linear relationship. For all three types of diene the values for pairs of cis and trans conformers do not differ very much, the ratio fcis/ ftrans being a little greater than 1 in ten cases and a little less than 1 in six cases. This lack of any marked difference between cis and trans conformers suggests that the coupling between the double bonds occurs in the main via the bonded framework of the molecule, and that "through-space" interactions, which would be a special feature of cis conformers, are of relatively little importance.

  17. Theoretical Study of Mechanism and Regioselectivity of 1,3-dipolar Cycloaddition of N-[methyl]-C-[5-nitro-2-furyl] Nitrilimine with Dimethyl 7-oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylate

    NASA Astrophysics Data System (ADS)

    Moeinpour, Farid

    2010-04-01

    The mechanism and regioselectivity of 1,3-dipolar cycloaddition of N-[methyl]-C-[5-nitro-2-furyl] nitrilimine with dimethyl 7-oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylate were investigated using activation energy calculations and density functional theory-based reactivity indexes. The reaction proceeds by an asynchronous concerted mechanism. The calculations are performed at the B3LYP/6-31G(d) level of theory and the obtained results are in agreement with experimental outcome.

  18. Eléments traces dans le sérum des enfants malnutris et bien nourris vivants à Lubumbashi et Kawama dans un contexte d'un environnement de pollution minière

    PubMed Central

    Musimwa, Aimée Mudekereza; Kanteng, Gray Wakamb; Kitoko, Hermann Tamubango; Luboya, Oscar Numbi

    2016-01-01

    Introduction La place des éléments traces métalliques essentiels en nutrition humaine ne peut plus être ignorée. Les déficits d'apports, les carences secondaires souvent sous – estimées, et les carences iatrogènes font le lit de pathologies telles que les infections et autres. D'où leurs dosages ont une importance particulière pour en évaluer la gravité et faciliter une prise en charge précoce ou améliorer le régime alimentaire. Cette étude a eu pour objectif de déterminer le profil sanguin en éléments traces (cuivre, sélénium, zinc, fer, chrome, cobalt, etc) chez les enfants malnutris et biens nourris dans un milieu minier à Lubumbashi. Méthodes Trois cents onze cas ont été colligés, 182 malnutris et 129 biens nourris, dans une étude descriptive transversale, effectuée de juillet 2013 à décembre 2014. Pour lequel un échantillonnage exhaustif a été réalisé. Le dosage des métaux dans le sérum s'est fait à l’ ICP-OES (spectrométrie de masse à plasma gon induit) au laboratoire de l'Office Congolais de Contrôle de Lubumbashi. Résultats Les oligoéléments essentiels (cuivre, zinc, sélénium et fer) se retrouvent à des concentrations très basses chez les enfants malnutris comme chez les biens nourris. L'arsenic, le cadmium, le magnésium et le manganèse se présentent à des concentrations normales par rapport aux valeurs de références chez les enfants biens nourris. L'antimoine, le chrome, le plomb et le cobalt se retrouvent élevés chez les malnutris et biens nourris. Le nickel est normal chez les malnutris et les biens nourris. Le magnésium, manganèse se sont présentés à des taux très bas chez les enfants malnutris. Conclusion Les enfants malnutris et biens nourris présentent une malnutrition aux oligo-éléments essentiels associés aux éléments traces métalliques. Ce qui permet de supposer qu'une carence en micronutriments essentiel favorise l'absorption des métaux lourds. PMID:27583075

  19. Crystal structure of 4,4-di­bromo-1-(3,4-di­meth­oxy­phen­yl)-2-aza­buta-1,3-diene-1-carbo­nitrile

    PubMed Central

    Chaabene, Marwa; Khatyr, Abderrahim; Knorr, Michael; Askri, Moheddine; Rousselin, Yoann; Kubicki, Marek M.

    2016-01-01

    The title compound, C12H10Br2N2O2, represents an example of a planar π-con­jugated 2-aza­butadiene mol­ecule, which is both an inter­esting starting material for further organic transformations and a potential ligand in organometallic coordination chemistry. Its metric mol­ecular parameters are typical for the family of 2-aza­buta-1,3-dienes not substituted at the (CH) 3-position. In the crystal, the almost planar (r.m.s. deviation = 0.0658 Å) aza­diene mol­ecules form one-dimensional double-wide ribbons through inter­molecular halogen bonds (C—Br⋯O and C—Br⋯Br—C), which then stack in a slipped manner through weak C—H⋯Br and π–π inter­actions to generate a three-dimensional network. PMID:27536405

  20. Structure of trichloro(diethylenetriamine)gold(II), Au(dien)Cl/sub 3/, determined by single-crystal x-ray diffraction, Raman, and EXAFS spectroscopies: an EXAFS caveat

    SciTech Connect

    Elder, R.C.; Watkins, J.W. II

    1986-01-15

    EXAFS spectroscopy of solid samples suggests that Au(dien)Cl/sub 3/ is a molecular entity with pseudooctahedral coordination. The three nitrogen donors from the dien ligand and one chlorine form an equatorial plane with two axial Au-Cl bonds of uncertain length (2.6 or 3.0 A) completing the coordination sphere. A single-crystal X-ray diffraction study confirms the overall structure but yields axial Au-Cl lengths of 3.121 (4) and 3.183 (3) A. The crystals are orthorhombic, space group Pbca, with cell constants a = 12.442 (5), b = 12.878 (9), and c = 13.177 (3) A and eight molecules per unit cell. These molecules were further characterized by Raman spectroscopy in solution as well as the solid state. Equatorial and axial Au-Cl stretching vibrations are observed for both phases, indicating some stability of the Au-Cl(axial) bonds in solution. 25 references, 3 figures, 4 tables.

  1. Identification of (3S, 9R)- and (3S, 9S)-megastigma-6,7-dien-3,5,9-triol 9-O-beta-D-glucopyranosides as damascenone progenitors in the flowers of Rosa damascena Mill.

    PubMed

    Suzuki, Masayuki; Matsumoto, Shigetaka; Mizoguchi, Masaya; Hirata, Satoshi; Takagi, Kazuteru; Hashimoto, Ikue; Yamano, Yumiko; Ito, Masayoshi; Fleischmann, Peter; Winterhalter, Peter; Morita, Tetuichiro; Watanabe, Naoharu

    2002-12-01

    The progenitors of damascenone (1), the most intensive C13-norisoprenoid volatile aroma constituent of rose essential oil, were surveyed in the flowers of Rosa damascena Mill. Besides 9-O-beta-D-glucopyranosyl-3-hydroxy-7,8-didehydro-beta-ionol (4b), a stable progenitor already isolated from the residual water after steam distillation of flowers of R. damascena Mill., two labile progenitors were identified to be (3S, 9R)- and (3S, 9S)-megastigma-6,7-dien-3,5,9-triol 9-O-beta-D-glucopyranosides (2b) based on their synthesis and HPLC-MS analytical data. Compound 2b gave damascenone (1), 3-hydroxy-beta-damascone (3) and 4b upon heating under acidic conditions. PMID:12596869

  2. ([2.2.2]Cryptand-κ6 O)potassium (η4-cyclo­octa­diene)bis­(η2-pyrene)cobaltate(1−) pentane hemisolvate

    PubMed Central

    Brennessel, William W.; Ellis, John E.

    2012-01-01

    The cation, anion, and solvent in the title compound, [K(C18H36N2O6)][Co(C8H12)(C16H10)2]·0.5C5H12, are well separated. The pentane solvent mol­ecules are found in channels along [100] and were modeled as disordered over crystallographic inversion centers. Using the mid-points of the coordinated olefins, the angle between the Cpy/Cpy–Co–Cpy/Cpy and the Ccod/Ccod–Co–Ccod/Ccod planes (py is pyrene and cod is cyclo­octa­diene) is 67.6 (2)°. Thus, the overall geometry of the coordination sphere around cobalt is best described as distorted tetra­hedral. PMID:22807709

  3. (18-Crown-6)potassium [(1,2,5,6-η)-cyclo­octa-1,5-diene][(1,2,3,4-η)-naph­tha­lene]­ferrate(−I)

    PubMed Central

    Brennessel, William W.; Ellis, John E.

    2012-01-01

    The title salt, [K(C12H24O6)][Fe(C8H12)(C10H8)], is the only known naphthalene complex containing iron in a formally negative oxidation state. Each (naphthalene)(1,5-cod)ferrate(−I) anion is in contact with one (18-crown-6)potassium cation via K⋯C contacts to the outer four carbon atoms of the naphthalene ligand (cod = 1,5-cyclo­octa­diene, 18-crown-6 = 1,4,7,10,13,16-hexa­oxacyclo­octa­deca­ne). When using the midpoints of the coordinating olefin bonds, the overall geometry of the coordination sphere around iron can be best described as distorted tetra­hedral. The naphthalene fold angle between the plane of the iron-coordinating butadiene unit and the plane containing the exo-benzene moiety is 19.2 (1)°. PMID:23125569

  4. Crystal structure of dimethyl 3,4,5,6-tetra­phenyl­cyclo­hexa-3,5-diene-1,2-di­carboxyl­ate

    PubMed Central

    Greenberg, Fred H.; Nazarenko, Alexander Y.

    2016-01-01

    In the title compound, C34H28O4, the cyclo­hexa­diene ring has a screw-boat conformation with a torsion angle between the double bonds being on average ca 15° [15.2 (3) and −15.3 (3) in the two independent mol­ecules]. All four phenyl rings in both mol­ecules are arranged in a propeller-like conformation. The two mol­ecules exhibit S,R- and R,S- chirality, respectively, and are connected via C—H⋯O inter­molecular inter­actions. In turn, these weakly bound dimers form the mol­ecular crystal. PMID:27555937

  5. High-Pressure Micellar Solutions of Symmetric and Asymmetric Styrene?Diene Diblocks in Compressible Near Critical Solvents: Micellization Pressures and Cloud Pressures Respond but Micellar Cloud Pressures Insensitive to Copolymer Molecular Weight, Concentration, and Block Ratio Changes

    SciTech Connect

    Winoto, Winoto; Tan, Sugata; Shen, Youqin; Radosz, Maciej; Hong, Kunlun; Mays, Jimmy

    2009-01-01

    Micellar solutions of polystyrene-block-polybutadiene and polystyrene-block-polyisoprene in propane are found to exhibit significantly lower cloud pressures than the corresponding hypothetical nonmicellar solutions. Such a cloud-pressure reduction indicates the extent to which micelle formation enhances the apparent diblock solubility in near-critical and hence compressible propane. Concentration-dependent pressure-temperature points beyond which no micelles can be formed, referred to as the micellization end points, are found to depend on the block type, size, and ratio. The cloud-pressure reduction and the micellization end point measured for styrene-diene diblocks in propane should be characteristic of all amphiphilic diblock copolymer solutions that form micelles in compressible solvents.

  6. [4+2] cycloaddition reactions between 1,8-disubstituted cyclooctatetraenes and diazo dienophiles: stereoelectronic effects, anticancer properties and application to the synthesis of 7,8-substituted bicyclo[4.2.0]octa-2,4-dienes.

    PubMed

    Grange, Rebecca L; Gallen, Michael J; Schill, Heiko; Johns, Jenny P; Dong, Lin; Parsons, Peter G; Reddell, Paul W; Gordon, Victoria A; Bernhardt, Paul V; Williams, Craig M

    2010-08-01

    A detailed examination of [4+2] cycloaddition reactions between 1,8-disubstituted cyclooctatetraenes and diazo compounds revealed that 4-phenyl-1,2,4-triazole-3,5-dione (PTAD) reacts to form either 2,3- or 3,4-disubstituted adducts. The product distribution can be controlled by modulating the electron density of the cyclooctatetraene. Unprecedented [4+2] cycloadditions between diisopropyl azodicarboxylate (DIAD) and 1,8-disubstituted cyclooctatetraenes are also described and further manipulation of a resulting cycloadduct uncovered a new pathway to the synthetically challenging bicyclo[4.2.0]octa-2,4-diene family. Variation of the substituents resulted in a range of compounds displaying selective action against different human tumour cell types. PMID:20572168

  7. Reactions of 7,8-dithiabicyclo[4.2.1]nona-2,4-diene 7-exo-oxide with dodecacarbonyl triiron Fe3(CO)12: a novel type of sulfenato thiolato diiron hexacarbonyl complexes.

    PubMed

    Windhager, Jochen; Apfel, Ulf-Peter; Yoshino, Tomoharu; Nakata, Norio; Görls, Helmar; Rudolph, Manfred; Ishii, Akihiko; Weigand, Wolfgang

    2010-07-01

    The reaction of Fe(3)(CO)(12) (13) with 7,8-dithiabicyclo[4.2.1]nona-2,4-diene 7-exo-oxide (12) yields the sulfenato-thiolato complex 14, which is used as starting material for further reactions. The disulfenato complex 17 is obtained by using one equivalent of dimethyldioxirane (DMD), and the monoepoxide 18 is prepared by the oxidation of 14 with an excess of DMD. Complex 14 can be converted to the monophosphine complexes 19a and 19b by subsequent substitution of one CO ligand using trimethylaminoxide Me(3)NO and triphenylphosphine PPh(3). Additional substitution reactions are done with 17 by using acetonitrile as a ligand to form 20a and 20b. In the electrochemical part of the paper, the reactions of the reduced iron species 14, 15, 17, and 19a are studied. PMID:20473980

  8. Analysis of the aliphatic monomer composition of polyesters associated with Arabidopsis epidermis: occurrence of octadeca-cis-6, cis-9-diene-1,18-dioate as the major component.

    PubMed

    Bonaventure, Gustavo; Beisson, Frédéric; Ohlrogge, John; Pollard, Mike

    2004-12-01

    Although the surface waxes from Arabidopsis thaliana leaves and stems have been thoroughly characterized, the monomer composition of the polyesters of the cuticular membrane has not been analyzed. Delipidated Arabidopsis leaves or stems, when depolymerized under conditions to cleave polyesters, produced typical omega-hydroxy fatty acid cutin monomers such as 16-hydroxy-palmitate, 10,16-dihydroxy-palmitate and 18-hydroxy-9,10-epoxy-stearate. However, the major monomer was octadeca-cis-6, cis-9-diene-1,18-dioate, with lesser amounts of octadec-cis-9-ene-1,18-dioate and hexadeca-1,16-dioate. These dicarboxylates were found predominantly in epidermal peels from Arabidopsis stems and are therefore likely to be associated with the cuticular membrane. They were also found in analyses of canola leaves but were absent in tomato and apple fruit cutins. In the fad2-1 mutant line of Arabidopsis, which has reduced levels of linoleate and linolenate and elevated oleate in cytosolic phospholipids, the amount of octadeca-cis-6, cis-9-diene-1,18-dioate was 50% reduced, with a concomitant increase in octadec-cis-9-ene-1,18-dioate. In a fatb-ko line of Arabidopsis, where the availability of cytosolic palmitate is impaired, there was an 80% loss of C16 monomers and a compensating increase in C18 monomers. The presence of substantial amounts of dicarboxylates in cuticular membranes is unexpected. High amounts of aliphatic dicarboxylates are usually considered as an indicator of suberin, and are reported only as very minor components of cutin. The high level of polyunsaturation is also unusual in cuticles; saturated fatty acid monomers usually predominate, with lesser amounts of monounsaturates. These novel findings for Arabidopsis demonstrate that a broad range of monomer compositions are possible for polyesters of the epidermis. PMID:15584957

  9. Synthesis of novel 17-(4'-formyl)pyrazolylandrosta-5,16-dienes and their derivatives as potent 17α-hydroxylase/C17,20-lyase inhibitors or antiproliferative agents depending on the substitution pattern of the heteroring.

    PubMed

    Kovács, Dóra; Wölfling, János; Szabó, Nikoletta; Szécsi, Mihály; Schelz, Zsuzsanna; Zupkó, István; Frank, Éva

    2016-09-14

    A series of novel 17-(4'-formyl)pyrazolylandrosta-5,16-dienes were efficiently synthesized in two steps from pregnadienolone acetate with monosubstituted hydrazines via the cyclization/formylation sequence of the primarily formed hydrazones on treatment with the Vilsmeier-Haack reagent. The products were further transformed by deacetylation and subsequent reduction in order to enlarge the compound library available for pharmacological studies. Moreover, 4'-formylpyrazoles containing H or Me on the heteroring-N were subjected to oxime formation and Ac2O-induced dehydration to furnish the corresponding 4'-cyano derivatives in good yields. The antiproliferative activities of the structurally related steroidal 17-exo-pyrazole derivatives were tested in vitro on four human adherent breast cancer cell lines (MCF7, T47D, MDA-MB-231 and MDA-MB-361): the microculture tetrazolium assay revealed that seven compounds exerted better cell growth-inhibitory effects on some or all these cell lines than those of the reference cisplatin. With regard to the well-known structural features that a potent C17,20-lyase inhibitor should possess, some relevant derivatives were tested in vitro from the aspects of their inhibitory effects on rat testicular enzyme, and one of them proved to exert noteworthy enzyme-inhibitory action, with an IC50 (26 nM) of the same order of magnitude as that of abiraterone. PMID:27209562

  10. Crystal structure of μ-fluorido-bis-{(η(4)-cyclo-octa-diene)[hexa-fluorido-anti-monato(V)]platinum(II)} hexa-fluorido-anti-monate(V) hydrogen fluoride 0.75-solvate.

    PubMed

    Seppelt, Konrad; Friedemann, Roland

    2016-01-01

    In the complex cation of the binuclear solvated title salt, [Pt2F(SbF6)2(C8H12)2]SbF6·0.75HF, an F atom bridges the two platinum(II) atoms with a bond angle of 123.3 (2)°. The corresponding Pt-F bond lengths are in the range of other fluorine-bridged binuclear platinum(II) complexes. Two of the three SbF6 (-) anions each coordinate with one F atom to one platinum(II) atom. Including the η(4)-bound cyclo-octa-diene (COD) ligands, the overall coordination sphere of each platinum(II) atom is square-planar. The third SbF6 (-) anion is not bound to the complex. Hydrogen fluoride is present in the crystal structure as a solvent disordered over three positions, each with an occupancy of 0.25. F⋯F distances of 2.5512 (7), 2.6076 (8) and 3.2215 (10) Å to surrounding SbF6 (-) anions are indicative of F-H⋯F hydrogen-bonding inter-actions although no H atoms could be localized for the disordered solvent mol-ecules. The resulting hydrogen-bonded network is three-dimensional. PMID:26870575

  11. The antidiabetic compound 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from averrhoa carambola L., demonstrates significant antitumor potential against human breast cancer cells

    PubMed Central

    Gao, Ying; Huang, Renbin; Gong, Yixuan; Park, Hyo Sim; Wen, Qingwei; Almosnid, Nadin Marwan; Chippada-Venkata, Uma D.; Hosain, Najlaa Abdulrhman; Vick, Eric; Farone, Anthony; Altman, Elliot

    2015-01-01

    2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) is a cyclohexanedione found in the roots of Averrhoa carambola L., commonly known as starfruit. Researchers have shown that DMDD has significant therapeutic potential for the treatment of diabetes; however, the effects of DMDD on human cancers have never been reported. We investigated the cytotoxic effects of DMDD against human breast, lung and bone cancer cells in vitro and further examined the molecular mechanisms of DMDD-induced apoptosis in human breast cancer cells. DMDD suppressed the growth of breast carcinoma cells, but not normal mammary epithelial cells, via induction of G1 phase cell cycle arrest, oxidative stress and apoptosis. DMDD increased the level of intracellular reactive oxygen species (ROS) and DMDD-induced ROS generation was found to be associated with the mitochondrial activity. The cytotoxicity that was induced by DMDD was attenuated by co-treatment with the antioxidant N-acetyl-L-cysteine (NAC). DMDD-induced cell apoptosis involved the activation of both the intrinsic mitochondrial pathway and the extrinsic receptor pathway. In addition, DMDD inhibited the canonical NF-κB signaling pathway at all steps, including TNF-α production, phosphorylation of NF-κB p65 and IκBα, as well as TNF-α activated NF-κB p65 nuclear translocation. Collectively, our studies indicate that DMDD has significant potential as a safe and efficient therapeutic agent for the treatment of breast cancer. PMID:26203774

  12. A comparison between the effects of gamma radiation and sulfur cure system on the microstructure and crosslink network of (styrene butadiene rubber/ethylene propylene diene monomer) blends in presence of nanoclay

    NASA Astrophysics Data System (ADS)

    Shoushtari Zadeh Naseri, Aida; Jalali-Arani, Azam

    2015-10-01

    Rubber blends based on (styrene-butadiene rubber (SBR)/ethylene-propylene-diene monomer (EPDM)) with and without organoclay (OC) were prepared through a melt mixing process. The concentration ratio of the rubber phases (EPDM/SBR; 50/50 wt%) and the amount of the OC were kept constant. The samples were then vulcanized by means of gamma radiation using a Co-60 gamma source as well as sulfur cure system. The effect of absorbed dose on the formation of the crosslinks was confirmed by the Fourier transform infrared spectroscopy (FTIR). The effects of absorbed dose, sulfur cure system and OC on the gel content, and crosslink density were evaluated by the chemical tests. Applying the Charlesby-Pinner equation to estimate the radiation chemical yield, revealed that the use of OC in the blend caused 20% reduction in the degradation/crosslinking ratio. Employing the swelling test data, some thermodynamic parameters were determined. Using field emission scanning electron microscopy (FE-SEM) to investigate microstructure of the samples revealed a more homogeneous structure and also an increase in compatibility of the blend components in the sample cured by the irradiation in comparison to that cured by the sulfur curing system.

  13. Therapeutic effects of C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me; bardoxolone methyl) on radiation-induced lung inflammation and fibrosis in mice

    PubMed Central

    Wang, Yan-Yang; Zhang, Cui-Ying; Ma, Ya-Qiong; He, Zhi-Xu; Zhe, Hong; Zhou, Shu-Feng

    2015-01-01

    The C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me), one of the synthetic triterpenoids, has been found to have potent anti-inflammatory and anticancer properties in vitro and in vivo. However, its usefulness in mitigating radiation-induced lung injury (RILI), including radiation-induced lung inflammation and fibrosis, has not been tested. The aim of this study was to explore the therapeutic effect of CDDO-Me on RILI in mice and the underlying mechanisms. Herein, we found that administration of CDDO-Me improved the histopathological score, reduced the number of inflammatory cells and concentrations of total protein in bronchoalveolar lavage fluid, suppressed secretion and expression of proinflammatory cytokines, including transforming growth factor-β and interleukin-6, elevated expression of the anti-inflammatory cytokine interleukin-10, and downregulated the mRNA level of profibrotic genes, including for fibronectin, α-smooth muscle actin, and collagen I. CDDO-Me attenuated radiation-induced lung inflammation. CDDO-Me also decreased the Masson’s trichrome stain score, hydroxyproline content, and mRNA level of profibrotic genes, and blocked radiation-induced collagen accumulation and fibrosis. Collectively, these findings suggest that CDDO-Me ameliorates radiation-induced lung inflammation and fibrosis, and this synthetic triterpenoid is a promising novel therapeutic agent for RILI. Further mechanistic, efficacy, and safety studies are warranted to elucidate the role of CDDO-Me in the management of RILI. PMID:26124639

  14. The antidiabetic compound 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from Averrhoa carambola L., demonstrates significant antitumor potential against human breast cancer cells.

    PubMed

    Gao, Ying; Huang, Renbin; Gong, Yixuan; Park, Hyo Sim; Wen, Qingwei; Almosnid, Nadin Marwan; Chippada-Venkata, Uma D; Hosain, Najlaa Abdulrhman; Vick, Eric; Farone, Anthony; Altman, Elliot

    2015-09-15

    2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) is a cyclohexanedione found in the roots of Averrhoa carambola L., commonly known as starfruit. Researchers have shown that DMDD has significant therapeutic potential for the treatment of diabetes; however, the effects of DMDD on human cancers have never been reported. We investigated the cytotoxic effects of DMDD against human breast, lung and bone cancer cells in vitro and further examined the molecular mechanisms of DMDD-induced apoptosis in human breast cancer cells. DMDD suppressed the growth of breast carcinoma cells, but not normal mammary epithelial cells, via induction of G1 phase cell cycle arrest, oxidative stress and apoptosis. DMDD increased the level of intracellular reactive oxygen species (ROS) and DMDD-induced ROS generation was found to be associated with the mitochondrial activity. The cytotoxicity that was induced by DMDD was attenuated by co-treatment with the antioxidant N-acetyl-L-cysteine (NAC). DMDD-induced cell apoptosis involved the activation of both the intrinsic mitochondrial pathway and the extrinsic receptor pathway. In addition, DMDD inhibited the canonical NF-κB signaling pathway at all steps, including TNF-α production, phosphorylation of NF-κB p65 and IκBα, as well as TNF-α activated NF-κB p65 nuclear translocation.Collectively, our studies indicate that DMDD has significant potential as a safe and efficient therapeutic agent for the treatment of breast cancer. PMID:26203774

  15. DNA incision evaluation, binding investigation and biocidal screening of novel metallonucleases of 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione based Knoevenagel condensate having methionine: Synthesis and structural validation

    NASA Astrophysics Data System (ADS)

    Chandrasekar, Thiravidamani; Pravin, Narayanaperumal; Raman, Natarajan

    2015-02-01

    Four new metallonucleases of the composition [MLCl] (where M = Cu(II), Ni(II), Zn(II) and Co(II); L = Knoevenagel condensate Schiff base, obtained by the condensation reaction of 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione with p-nitrobenzaldehyde and methionine amino acid) have been synthesised and characterized thoroughly by microanalytical data, magnetic susceptibility, molar conductivity, UV-Vis., IR, 1H NMR, 13C NMR and EPR spectral techniques. Their geometry is investigated and established to have square planar geometry. Electronic absorption spectroscopy, cyclic voltammetry and viscosity measurements reveal that the complexes strongly bind to calf thymus DNA via an intercalation mechanism. DNA cleavage efficiency of these complexes is explored by gel electrophoresis, and they are found to endorse the cleavage of pBR322 DNA in presence of oxidant H2O2. These results reveal that all the complexes show better nuclease activity. Moreover, the biological screening against few pathogens reveals that that the complexes have potent biocidal activity than the free ligand.

  16. Methyl 2-Cyano-3,11-dioxo-18-olean-1,12-dien-30-oate (CDODA-Me), a Derivative of Glycyrrhetinic Acid, Functions as a Potent Angiogenesis Inhibitor

    PubMed Central

    Pang, Xiufeng; Zhang, Li; Wu, Yougen; Lin, Lei; Li, Jingjie; Qu, Weijing; Safe, Stephen

    2010-01-01

    Methyl 2-cyano-3,11-dioxo-18-olean-1,12-dien-30-oate (CDODA-Me), a triterpenoid acid derived synthetically from glycyrrhetinic acid, has been characterized as a peroxisome proliferator-activated receptor γ agonist with a broad range of receptor-dependent and -independent anticancer activities. Although CDODA-Me decreases the expression of some angiogenic genes in cancer cells, the direct effects of this compound on angiogenesis have not been defined. In this study, we have extensively investigated the activities of CDODA-Me in multiple angiogenesis assays. Our results showed that this agent inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration, invasion, and lamellipodium and capillary-like structure formation of human umbilical endothelial cells (HUVECs) in a concentration-dependent manner. Moreover, CDODA-Me abrogated VEGF-induced sprouting of microvessels from rat aortic rings ex vivo and inhibited the generation of new vasculature in the Matrigel plugs in vivo, where CDODA-Me significantly decreased the number of infiltrating von Willebrand factor-positive endothelial cells. To understand the molecular basis of this antiangiogenic activity, we examined the signaling pathways in CDODA-Me-treated HUVECs. Our results showed that CDODA-Me significantly suppressed the activation of VEGF receptor 2 (VEGFR2) and interfered with the mammalian target of rapamycin (mTOR) signaling, including mTOR kinase and its downstream ribosomal S6 kinase (S6K), but had little effect on the activities of extracellular signal-regulated protein kinase and AKT. Taken together, CDODA-Me blocks several key steps of angiogenesis by inhibiting VEGF/VEGFR2 and mTOR/S6K signaling pathways, making the compound a promising agent for the treatment of cancer and angiogenesis-related pathologies. PMID:20631299

  17. Crystal structure of (18-crown-6)potassium(I) [(1,2,3,4,5-η)-cyclo­hepta­dien­yl][(1,2,3-η)-cyclo­hepta­trien­yl]cobalt(I)

    PubMed Central

    Brennessel, William W.; Ellis, John E.

    2015-01-01

    The reaction of bis­(anthracene)cobaltate(−I) with excess cyclo­hepta­triene, C7H8, resulted in a new 18-electron cobaltate containing two different seven-membered ring ligands, based on single-crystal X-ray diffraction. The asymmetric unit of this structure contains two independent cation–anion pairs of the title complex, [K(18-crown-6)][Co(η3-C7H7)(η5-C7H9)], where 18-crown-6 stands for 1,4,7,10,13,16-hexa­oxa­cyclo­octa­decane (C12H24O6), in general positions and well separated. Each (18-crown-6)potassium cation is in contact with the η3-coordinating ligand of one cobaltate complex. Each η3-coordinating ligand behaves as an allylic anion whose exo-diene moiety is bent away from the allylic plane, and thus is not involved directly in the bonding. The metal-coordinating portions of the anionic η5 ligands are planar and one of these ligands is modeled as disordered over two positions, with occupancy ratio 0.699 (5):0.301 (5), such that one orientation is rotated by one carbon atom with respect to the other. The diffraction intensities were integrated according to non-merohedral twin law [-1 0 0/0 -1 0/0.064 0 1], a 180° rotation about reciprocal lattice axis [001], and the masses of the twin domains refined to equal amounts. As both ligands are formally coordinated as anions, the cobalt atom is best considered to be CoI. This compound is of inter­est as the first to possess cyclo­hepta­trienyl and cyclo­hepta­dienyl ligands in an anionic metal complex. PMID:25844191

  18. In Vitro Activity of 2-methoxy-1,4-naphthoquinone and Stigmasta-7,22-diene-3β-ol from Impatiens balsamina L. against Multiple Antibiotic-Resistant Helicobacter pylori

    PubMed Central

    Wang, Yuan-Chuen; Li, Wan-Yu; Wu, Deng-Chyang; Wang, Jeh-Jeng; Wu, Cheng-Hsun; Liao, Jyun-Ji; Lin, Cheng-Kun

    2011-01-01

    Infection with Helicobacter pylori is strongly associated with gastric cancer and gastric adenocarcinoma. WHO classified H. pylori as a group 1 carcinogen in 1994. Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures and fingernail inflammation. In this study, we isolated anti-H. pylori compounds from this plant and investigated their anti- and bactericidal activity. Compounds of 2-methoxy-1,4-naphthoquinone (MeONQ) and stigmasta-7,22-diene-3β-ol (spinasterol) were isolated from the pods and roots/stems/leaves of I. balsamina L., respectively. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) for MeONQ were in the ranges of 0.156–0.625 and 0.313–0.625 μg mL−1, respectively, and in the ranges of 20–80 μg mL−1 both of MICs and MBCs for spinasterol against antibiotic (clarithromycin, metronidazole and levofloxacin) resistant H. pylori. Notably, the activity of MeONQ was equivalent to that of amoxicillin (AMX). The bactericidal H. pylori action of MeONQ was dose-dependent. Furthermore, the activity of MeONQ was not influenced by the environmental pH values (4–8) and demonstrated good thermal (121°C for 15 min) stability. MeONQ abounds in the I. balsamina L. pod at the level of 4.39% (w/w db). In conclusion, MeONQ exhibits strong potential to be developed as a candidate agent for the eradication of H. pylori infection. PMID:19773391

  19. A focal adhesion kinase inhibitor 16-hydroxy-cleroda-3,13-dien-16,15-olide incorporated into enteric-coated nanoparticles for controlled anti-glioma drug delivery.

    PubMed

    Thiyagarajan, Varadharajan; Lin, Shi-Xiang; Lee, Chia-Hung; Weng, Ching-Feng

    2016-05-01

    16-Hydroxy-cleroda-3,13-dien-16,15-olide (HCD) which is extracted from a medicinal plant, Polyalthia longifolia, was shown to exhibit anticancer activity through apoptosis and FAK inhibition in our previous study. To improve its solubility and efficacy, a novel HCD delivery system using copper-substituted mesoporous silica nanoparticles (MSNs) was designed as a delivery vehicle, and the outer surfaces of MSNs were further coated with enteric polymers to prevent the drug from leaching in the stomach acid. All the data regarding synthesis and physical characterization, including Zeta potential, FT-IR spectra, N2 adsorption-desorption isotherms (BET), drug loading, powder X-ray diffraction, Thermo gravimetric analysis (TGA), Transmission electron microscopy (TEM), and Scanning electron microscopy (SEM) were well characterized. The non-coated MSN-HCD exposed to acidic pH (1.2) showed a rapid degradation of the drug, whereas the enteric-coated samples presented a sustained release profile in the gastrointestinal pHs. Cell cytotoxicity was further confirmed by the MTT-C6 Glioma cell line, in vitro. When compared with the control and pure HCD, the MSN-HCD revealed a potential anti-proliferation effect via the synergistic effect of the drug and the MSN vehicle. Additionally, this MSN-HCD had the effect of increasing the reactive oxygen species (ROS) levels and altered the Mitochondria membrane potential (MMP) in C6 cell line. The in vivo anti-tumor efficacy of enteric-coated MSN-HCD was evaluated by C6 Glioma bearing xenograft nude mice, and enteric-coated MSN-HCD clearly exhibited the greatest anti-glioma activity, as compared to the pure HCD and the untreated control. In terms of the effective treatment of brain glioma, this study provides conclusive evidence of the successful development of the anti-cancer agent HCD conjugated with enteric-coated MSN as a delivery control mechanism with enhanced dissolution characteristics. PMID:26851441

  20. A mutant form of 3-ketosteroid-Δ(1)-dehydrogenase gives altered androst-1,4-diene-3, 17-dione/androst-4-ene-3,17-dione molar ratios in steroid biotransformations by Mycobacterium neoaurum ST-095.

    PubMed

    Shao, Minglong; Zhang, Xian; Rao, Zhiming; Xu, Meijuan; Yang, Taowei; Li, Hui; Xu, Zhenghong; Yang, Shangtian

    2016-05-01

    Mycobacterium neoaurum ST-095 and its mutant M. neoaurum JC-12, capable of transforming phytosterol to androst-1,4-diene-3,17-dione (ADD) and androst-4-ene-3,17-dione (AD), produce very different molar ratios of ADD/AD. The distinct differences were related to the enzyme activity of 3-ketosteroid-Δ(1)-dehydrogenase (KSDD), which catalyzes the C1,2 dehydrogenation of AD to ADD specifically. In this study, by analyzing the primary structure of KSDDI (from M. neoaurum ST-095) and KSDDII (from M. neoaurum JC-12), we found the only difference between KSDDI and KSDDII was the mutation of Val(366) to Ser(366). This mutation directly affected KSDD enzyme activity, and this result was confirmed by heterologous expression of these two enzymes in Bacillus subtilis. Assay of the purified recombinant enzymes showed that KSDDII has a higher C1,2 dehydrogenation activity than KSDDI. The functional difference between KSDDI and KSDDII in phytosterol biotransformation was revealed by gene disruption and complementation. Phytosterol transformation results demonstrated that ksdd I and ksdd II gene disrupted strains showed similar ADD/AD molar ratios, while the ADD/AD molar ratios of the ksdd I and ksdd II complemented strains were restored to their original levels. These results proved that the different ADD/AD molar ratios of these two M. neoaurum strains were due to the differences in KSDD. Finally, KSDD structure analysis revealed that the Val(366)Ser mutation could possibly play an important role in stabilizing the active center and enhancing the interaction of AD and KSDD. This study provides a reliable theoretical basis for understanding the structure and catalytic mechanism of the Mycobacteria KSDD enzyme. PMID:26886757

  1. 2-Cyano-3,12-dioxoolean-1,9-dien-28-oic acid and related compounds inhibit growth of colon cancer cells through peroxisome proliferator-activated receptor gamma-dependent and -independent pathways.

    PubMed

    Chintharlapalli, Sudhakar; Papineni, Sabitha; Konopleva, Marina; Andreef, Michael; Samudio, Ismael; Safe, Stephen

    2005-07-01

    2-Cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) and the corresponding methyl (CDDO-Me) and imidazole (CDDO-Im) esters induce peroxisome proliferator-activated receptor gamma (PPARgamma)-dependent transactivation in SW-480 colon cancer cells, and these responses were inhibited by small inhibitory RNA for PPARgamma. Moreover, in a mammalian two-hybrid assay using the PPARgamma(2)-VP16 fusion plasmid and GAL4-coactivator/corepressor chimeras and a construct (pGAL4) containing five tandem GAL4 response elements, CDDO, CDDO-Me, and CDDO-IM induce transactivation and PPARgamma interaction with multiple coactivators. A major difference among the three PPARgamma agonists was the higher activity of CDDO-Im to induce PPARgamma interactions with the corepressor SMRT. CDDO, CDDO-Me, and CDDO-Im inhibited SW-480, HCT-116, and HT-29 colon cancer cell proliferation at low concentrations and induced cell death at higher concentrations. Growth inhibition at lower concentrations correlated with induction of the tumor suppressor gene caveolin-1 which is known to inhibit colon cancer cell growth. Induction of caveolin-1 by CDDO, CDDO-Me, and CDDO-Im was inhibited by the PPARgamma antagonist N-(4'-aminopyridyl-2-chloro-5-nitrobenzamide (T007), whereas higher doses induced apoptosis [poly(ADP-ribose) polymerase cleavage], which was not inhibited by T007. These results illustrate that CDDO-, CDDO-Me, and CDDO-Im induce both PPARgamma-dependent and -independent responses in colon cancer cells, and activation of these pathways are separable and concentration-dependent for all three compounds. PMID:15798084

  2. Ultraviolet photochemistry of Co{sup III}L(H{sub 2}O)SO{sub 3}{sup +} [L = Me{sub 6}[14]dieneN{sub 4}, [14]aneN{sub 4}] complexes. Quandaries about the linkage isomerization to O-bonded sulfite and the photogeneration of cobalt(I) in sequential biphotonic photolysis

    SciTech Connect

    Gibney, S.C.; Ferraudi, G.; Shang, M.

    1999-06-14

    The catalyzed and uncatalyzed oxidation of sulfite have been a matter of continued interest. Attention to these processes has a basic science motive as well as the need to resolve a number of long-recognized technical problems, i.e., gas desulfurization, pollution, and health problems. Two new macrocyclic complexes with S-bonded sulfite, Co(Me{sub 6}[14]diene N{sub 4})(H{sub 2}O)SO{sub 3}{sup +} and Co([14]ane N{sub 4})(H{sub 2}O)SO{sub 3}{sup +}, were prepared. The type of the So{sub 3}{sup 2{minus}} linkage in [Co(Me{sub 6}[14]diene N{sub 4})(H{sub 2}O)SO{sub 3}]ClO{sub 4} was established by means of the X-ray structure (crystal system, orthorhombic). In a study of the photochemical properties, transient spectra revealed the photoredox formation of Co(II) macrocycles and the photoisomerization to O-bonded sulfite. Precursors of these products were also observed and tentatively identified as an ion pair and an adduct of the SO{sub 3}{sup {sm_bullet}{minus}} radical and the unsaturated macrocycle Me{sub 6}[14]diene N{sub 4}. The photogeneration of SO{sub 3}{sup {sm_bullet}{minus}} was verified by means of the radical`s ESR spectrum. High power laser irradiations resulted in the secondary photolysis of the intermediates and the formation of Co(I) products. The mechanism of the primary and secondary photolysis is discussed.

  3. (2R*,4R*,7S*,10R*,12R*)-3,11,13,15-Tetra­oxa­penta­cyclo­[5.5.3.01,7.02,4.010,12]penta­deca-5,8-dien-14-one

    PubMed Central

    Mehta, Goverdhan; Sen, Saikat; Kumar, C. S. Ananda

    2013-01-01

    The title compound, C11H8O5, features a ‘skipped’ diene, an anti-bis­(epoxide) and a cyclic carbonate, all embedded in a densely functionalized [4.4.3]propellane scaffold. The crystal packing of this diepoxide is effected primarily by C—H⋯O hydrogen bonds, which link the mol­ecules into tapes along the b axis. Inter-tape connectivity is brought about by centrosymmetrically disposed pairs of C⋯O contacts [3.183 (4) Å] between the Cδ+=Oδ- dipoles of neighbouring carbonate moieties. PMID:24098200

  4. Androgen receptor inactivation contributes to antitumor efficacy of 17{alpha}-hydroxylase/17,20-lyase inhibitor 3beta-hydroxy-17-(1H-benzimidazole-1-yl)androsta-5,16-diene in prostate cancer.

    PubMed

    Vasaitis, Tadas; Belosay, Aashvini; Schayowitz, Adam; Khandelwal, Aakanksha; Chopra, Pankaj; Gediya, Lalji K; Guo, Zhiyong; Fang, Hong-Bin; Njar, Vincent C O; Brodie, Angela M H

    2008-08-01

    We previously reported that our novel compound 3beta-hydroxy-17-(1H-benzimidazole-1-yl)androsta-5,16-diene (VN/124-1) is a potent 17alpha-hydroxylase/17,20-lyase (CYP17) inhibitor/antiandrogen and strongly inhibits the formation and proliferation of human prostate cancer LAPC4 tumor xenografts in severe combined immunodeficient mice. In this study, we report that VN/124-1 and other novel CYP17 inhibitors also cause down-regulation of androgen receptor (AR) protein expression in vitro and in vivo. This mechanism of action seems to contribute to their antitumor efficacy. We compared the in vivo antitumor efficacy of VN/124-1 with that of castration and a clinically used antiandrogen, Casodex, and show that VN/124-1 is more potent than castration in the LAPC4 xenograft model. Treatment with VN/124-1 (0.13 mmol/kg twice daily) was also very effective in preventing the formation of LAPC4 tumors (6.94 versus 2410.28 mm(3) in control group). VN/124-1 (0.13 mmol/kg twice daily) and VN/124-1 (0.13 mmol/kg twice daily) + castration induced regression of LAPC4 tumor xenografts by 26.55% and 60.67%, respectively. Treatments with Casodex (0.13 mmol/kg twice daily) or castration caused significant tumor suppression compared with control. Furthermore, treatment with VN/124-1 caused marked down-regulation of AR protein expression, in contrast to treatments with Casodex or castration that caused significant up-regulation of AR protein expression. The results suggest that VN/124-1 acts by several mechanisms (CYP17 inhibition, competitive inhibition, and down-regulation of the AR). These actions contribute to inhibition of the formation of LAPC4 tumors and cause regression of growth of established tumors. VN/124-1 is more efficacious than castration in the LAPC4 xenograft model, suggesting that the compound has potential for the treatment of prostate cancer. PMID:18723482

  5. Clinical association of baseline levels of conjugated dienes in low-density lipoprotein and nitric oxide with aggressive B-cell non-Hodgkin lymphoma and their relationship with immunoglobulins and Th1-to-Th2 ratio

    PubMed Central

    Haddouche, Mustapha; Meziane, Warda; Hadjidj, Zeyneb; Mesli, Naima; Aribi, Mourad

    2016-01-01

    Objective The aim of this study was to highlight the clinical association of baseline levels of conjugated dienes in low-density lipoprotein (LDL-BCD) and nitric oxide (NO) with immunoglobulins (Igs) and T helper (Th)1/Th2 ratio in patients with newly diagnosed B-cell non-Hodgkin lymphoma (NHL). Patients and methods Thirty-two newly diagnosed patients with aggressive B-cell NHL and 25 age-, sex-, and body-mass-index-matched healthy controls were randomly selected for a cross-sectional case–control study conducted at the Hematology Department of Tlemcen Medical Centre University (northwest of Algeria). Results Circulating levels of LDL-BCD and NO and those of IgA and IgM were significantly higher in patients than in controls. The levels of Th1/Th2 ratio and plasma total antioxidant capacity were significantly lower in patients compared with controls, while malondialdehyde and protein carbonyl levels were significantly higher in patients. B-cell NHL was significantly associated with high levels of LDL-BCD from 25th to 75th percentile (25th percentile: relative risk [RR] =2.26, 95% confidence interval [CI] 1.42–3.59, P=0.014; 50th percentile: RR =2.84, 95% CI 1.72–4.68, P<0.001; 75th percentile: RR =5.43, 95% CI 2.58–11.42, P<0.001). Similarly, the disease was significantly associated with high levels of NO production from 25th to 75th percentile (25th percentile: RR =2.07, 95% CI 1.25–3.44, P=0.024; 50th percentile: RR =2.78, 95% CI 1.63–4.72, P<0.001; 75th percentile: RR =4.68, 95% CI 2.21–9.91, P<0.001). Moreover, LDL-BCD levels were positively and significantly correlated with interferon (IFN)-γ, whereas NO levels were inversely and significantly correlated with IFN-γ and Th1/Th2 ratio. Conclusion LDL-BCD and NO production seem to be associated with aggressive B-cell NHL and alteration of Th1/Th2 ratio. Our results have to be examined using ex vivo mechanistic studies leading to further investigations of these parameters, with an interest in the

  6. Crystal structure of (±)-(1SR,5SR,6SR,7SR,10SR,11SR,13SR)-13-benz­yloxy-7-meth­oxy­meth­oxy-11,15,18,18-tetra­methyl-3-oxo-2,4-dioxa­tetra­cyclo­[12.3.1.01,5.06,11]octa­deca-14,16-dien-10-yl benzoate

    PubMed Central

    Oishi, Takeshi; Fukaya, Keisuke; Yamaguchi, Yu; Sugai, Tomoya; Watanabe, Ami; Sato, Takaaki; Chida, Noritaka

    2015-01-01

    In the title compound, C36H42O8, the dioxolane ring adopts a twist conformation; the two adjacent C atoms deviate alternately from the mean plane of other atoms by −0.287 (5) and 0.174 (5) Å. The cyclo­hexane, cyclo­hexa­diene and central cyclo­octane rings show chair, half-chair and boat–chair forms, respectively. As a result of the strained ring system, the tetra­subsituted olefin in the cyclo­hexa­diene is skewed from an ideal planar structure. In the crystal, C—H⋯O hydrogen bonds connect the mol­ecules into a sheet parallel to (100). The sheets are further linked by other weak C—H⋯O and C—H⋯π inter­actions, forming a three-dimensional network. PMID:25995863

  7. catena-Poly[[bis­(ethanol-κO)mangan­ese(II)]-μ-2,5-di­chloro-3,6-di­oxo­cyclo­hexa-1,4-diene-1,4-bis­(olato)-κ4 O 1,O 6:O 3,O 4

    PubMed Central

    Tanaka, Seiya; Himegi, Akiko; Ohishi, Tomomi; Fuyuhiro, Akira; Kawata, Satoshi

    2014-01-01

    In the title coordination polymer, [Mn(C6Cl2O4)(C2H5OH)2]n, the MnII atom and the chloranilate [systematic name: 2,5-di­chloro-3,6-dioxo­cyclo­hexa-1,4-diene-1,4-bis­(olate)] ion lie on crystallographic inversion centers. The geometry around the MnII atom is a distorted octa­hedron involving four O atoms of two chloranilate ions and two O atoms from two ethanol mol­ecules. The chloranilate ion serves as a bridging ligand between the MnII ions, leading to an infinite linear chain along the b-axis direction. The chains are linked by O—H⋯O hydrogen bonds between the apically coordinating ethanol mol­ecule and the chloranilate ion, affording a two-dimensional layer expanding parallel to the ab plane. PMID:24764952

  8. Dichlorido-1κCl,3κCl-hexa­kis­[1,1,2,2,3,3(η5)-cyclo­penta­dien­yl]di-μ2-oxido-1:2κ2 O:O;2:3κ2 O:O-trizirconium(IV)

    PubMed Central

    Kraft, Bradley M.; Brennessel, William W.

    2012-01-01

    The title compound, [Zr3(C5H5)6Cl2O2], exists as discrete mol­ecules possessing a series of three Cp2Zr units (Cp is cyclo­penta­dien­yl) bridged by oxide ligands and end-capped by chloride ligands. The Cp planes in the central and terminal zirconocene units form dihedral angles of 53.3 (2) and 53.5 (2)°, respectively. The two Zr—O—Zr bridge angles are nearly linear and form a planar Zr3O2 core. The mol­ecule bears C2 symmetry with the central Zr atom lying on a crystallographic twofold axis. PMID:22807735

  9. Synthesis of Pyrazolo[5,1-a]isoindoles and Pyrazolo[5,1-a]isoindole-3-carboxamides through One-Pot Cascade Reactions of 1-(2-Bromophenyl)buta-2,3-dien-1-ones with Isocyanide and Hydrazine or Acetohydrazide.

    PubMed

    Tian, Miaomiao; He, Yan; Zhang, Xinying; Fan, Xuesen

    2015-08-01

    A novel and efficient method for the construction of the pyrazolo[5,1-a]isoindole scaffold via a one-pot three-component cascade reaction of 1-(2-bromophenyl)buta-2,3-dien-1-one with hydrazine and isocyanide promoted by a Pd catalyst is described. This cascade process proceeds through initial condensation of the allenic ketone with hydrazine followed by Pd-catalyzed isocyanide insertion into the C-Br bond and intramolecular C-N bond formation. Interestingly, when acetohydrazide was used in place of hydrazine, a more sophisticated procedure involving condensation, isocyanide insertion into C-H and C-Br bonds, deacetylation, and formation of C-C, C-O, and C-N bonds occurred to afford pyrazolo[5,1-a]isoindole-3-carboxamides with good efficiency. PMID:26153651

  10. [2,5-Bis(2,2'-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene]dichloridomanganese(II): from a mononuclear compound to a three-dimensional supramolecular framework through C-H···Cl hydrogen bonds and π-π stacking interactions.

    PubMed

    Lu, Zhengliang; Zhao, Yuanchao; Chen, Baolian; Huang, Ximing; Fan, Chunhua

    2014-07-01

    The title compound, [MnCl2(C24H20N6)], has been synthesized and characterized based on the multifunctional ligand 2,5-bis(2,2'-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene (L). The Mn(II) centre is five-coordinate with an approximately square-pyramidal geometry. The L ligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one-dimensional chain by two C-H···Cl hydrogen bonds. These chains are assembled into a two-dimensional layer through π-π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three-dimensional supramolecular framework is attained through π-π stacking interactions between adjacent coordinated bipyridyl groups. PMID:24992119

  11. Trichlorido{2-[2-(η5-cyclo­penta­dien­yl)-2-methyl­prop­yl]-1-trimethyl­silyl-1H-imidazole-κN 3}titanium(IV) tetra­hydro­furan hemisolvate

    PubMed Central

    Ge, Fang; Nie, Wanli; Borzov, Maxim V.; Churakov, Andrei V.

    2010-01-01

    The title compound, [Ti(C15H23N2Si)Cl3]·0.5C4H8O, has been prepared from {2-[2-(η5-cyclo­penta­dien­yl)-2-methyl­prop­yl]-1H-imidazolyl-κN 1}bis­(N,N-diethyl­amido-κN)titanium(IV), (C12H14N2)Ti(NEt2)2, by reaction with excess of Me3SiCl in tetra­hydro­furan (THF) at 353 K. The crystal structure contains THF as adduct solvent, disordered around a center of inversion. The presence of THF and the adduct ratio has been independently supported by 1H NMR spectroscopy. The coordination polyhedron of the Ti atom is distorted square-pyramidal, assuming the cyclo­penta­dienyl (Cp) ring occupies one coordination site. The Ti, Si and CH2 group C atoms only deviate slightly from the imidazole ring plane [by 0.021 (4), 0.133 (4) and 0.094 (4) Å, respectively]. Comparison of the principal geometric parameters with those of the few known structurally characterized analogues reveal small differences in bond lengths and angles at the Ti atom. The title complex is only stable in THF-d 8 in the presence of excess Me3SiCl, otherwise it exists in an equilibrium with equimolar amounts of dichlorido{2-[2-(η5-cyclo­penta­dien­yl)-2-methyl­prop­yl]-1H-imidazolyl-κN 3}titanium(IV) and chloro­trimethyl­silane. PMID:21579034

  12. Synthesis and pharmacological evaluations of new steroidal anti-inflammatory antedrugs: 9alpha-Fluoro-11beta,17alpha,21-trihydroxy-3,20-dioxo-pregna-1,4-diene-16alpha-carboxylate (FP16CM) and its derivatives.

    PubMed

    Park, Kwan-Kyun; Ko, Dong-Hoon; You, Zhengqing; Heiman, Ann S; Lee, Henry Joung

    2006-01-01

    In continuing efforts to develop potent anti-inflammatory steroids without systemic adverse effects, methyl 9alpha-fluoro-11beta,17alpha,21-trihydroxy-3,20-dioxo-pregna-1,4-diene-16alpha-carboxylate (FP16CM) and its 16-alkoxycarbonyl derivatives (FP16CE, FP16CP and FP16CB) were synthesized based on the antedrug concept. The steroids were evaluated for their pharmacological activities and adverse systemic effects. All steroidal antedrugs showed both binding affinity to the glucocorticoid receptor in liver cytosol and inhibitory effect on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophage cell. These compounds also inhibited croton-oil-induced ear edema and showed no systemic effects such as thymus atrophy and suppression of corticosterone level after 5-day treatment. Among those compounds tested, FP16CM showed the highest activities in receptor binding, NO inhibition and ear edema, these activities were comparable to those of prednisolone. Hydrolysis study in plasma showed that FP16CB was hydrolyzed rapidly, with the half-live (T1/2) of 3.2 min and the half-lives of other compounds were between 16.9 and 29.4 min. These results support the antedrug concept, of which the decrease in systemic adverse effects is attributed to fast hydrolysis to inactive metabolite in the systemic circulation. PMID:16280144

  13. "Bien Educado": Measuring the Social Behaviors of Mexican American Children

    ERIC Educational Resources Information Center

    Bridges, Margaret; Cohen, Shana R.; McGuire, Leah Walker; Yamada, Hiro; Fuller, Bruce; Mireles, Laurie; Scott, Lyn

    2012-01-01

    Young children's expected social behaviors develop within particular cultural contexts and contribute to their academic experience in large part through their relationships with their teachers. Commonly used measures focus on children's problem behaviors, developed from psychopathology traditions, and rarely situate normative and positive…

  14. Levels of polychlorinated dibenzodioxins and polychlorinated dibenzofurans in breast milk samples from three dioxin-contaminated hotspots of Vietnam.

    PubMed

    Manh, Ho Dung; Kido, Teruhiko; Tai, Pham The; Okamoto, Rie; Honma, Seijiro; Liang, Sun Xian; Anh, Le Thai; Maruzeni, Shoko; Nghi, Tran Ngoc; Nishijo, Muneko; Nakagawa, Hideaki; Nhu, Dang Duc; Van Tung, Dao; Hung, Nguyen Ngoc; Son, Le Ke

    2015-04-01

    We determined polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in breast milk of 143 primiparae living around the three most dioxin-contaminated areas of Vietnam. The women sampled lived in the vicinity of former U.S. air bases at Bien Hoa (n=51), Phu Cat (n=23), and Da Nang (n=69), which are known as dioxin hotspots. Breast milk samples from Bien Hoa City, where residents live very close to the air base, showed high levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), with 18% of the samples containing >5 pgTCDD/g lipid. However, Phu Cat residents lived far from the air base and their samples showed lower TCDD levels, with none containing >5 pgTCDD/g lipid. In Da Nang, TCDD levels in mothers from Thanh Khe (close to the air base, n=43) were significantly higher than those in mothers from Son Tra (far from the air base, n=26), but not other PCDD and PCDF (PCDD/F) congeners. Although TCDD levels in Bien Hoa were the highest among these hotspots, levels of other PCDD/F congeners as well as the geometric mean concentration of total PCDD/F level in Bien Hoa (9.3 pg toxic equivalents [TEQ]/g lipid) were significantly lower than the level observed in Phu Cat (14.1 pgTEQ/g lipid), Thanh Khe (14.3 pgTEQ/g lipid), and Son Tra (13.9 pgTEQ/g lipid). Our findings indicated that residents living close to former U.S. air bases were exposed to elevated levels of TCDD, but not of other PCDD/F congeners. PMID:25569577

  15. Numerical Simulation of Petroleum Generation and Migration in the Song Hong Basin, Vietnam

    NASA Astrophysics Data System (ADS)

    Son, Byeong-Kook; Thi Nguyen, Hong; Park, Mee-Sook

    2014-05-01

    The numerical modeling of petroleum systems is an effective tool to understand generation, migration and accumulation of hydrocarbons in a sedimentary basin and hence to determine future targets for the hydrocarbon exploration. The numerical modeling identifies two petroleum systems in the Song Hong Basin, which is a petroliferous Cenozoic basin, offshore eastern Vietnam. These petroleum systems were named DinhCao-PhuCu(.) Petroleum System and SongHuong-BienDong(.) Petroleum System. DinhCao-PhuCu(.) Petroleum System covers northern and central parts of the Song Hong basin with Oligocene shale and coaly shale source rocks of Dinh Cao formation, which are dominated by type II-III kerogens. The hydrocarbon generation starts at 13 Ma within deeply buried Oligocene strata located in the centre of the basin. The hydrocarbon expels from the Oligocene source rock and migrates laterally and then up dip toward marginal areas where Middle Miocene sandstones of Phu Cu formation are present as major reservoirs. The numerical model shows that the critical moment occurs at about 3.5 Ma. The DinhCao-PhuCu(.) petroleum system is confirmed by sparse occurrence of oil and gas along the coast of eastern Vietnam. SongHuong-BienDong(.) Petroleum System is identified in limited areas of the central and southern Song Hong basin. The major source rock of this petroleum system is Lower Miocene dark claystones of Song Huong formation which contain gas prone, type III kerogen. The migration model shows that hydrocarbons are generated from the Miocene source rocks in the center of the basin at about 12 Ma, and migrates updip through sand bodies of Quang Ngai formation to the major boundaries faults, and further moves into highly permeable up-dipping units, the Bien Dong formation. The best depiction of the generation-migration-accumulation of hydrocarbons occurs at about 2 Ma. The presence of the SongHuong-BienDong(.) Petroleum System is indicated by the large gas fields in the central and

  16. New provincial records of skinks (Squamata: Scincidae) from northwestern Vietnam

    PubMed Central

    Pham, Anh Van; Le, Dzung Trung; Nguyen, Son Lan Hung; Ziegler, Thomas

    2015-01-01

    Abstract We report six new records of skinks from northwestern Vietnam: Eutropis macularius, Scincella devorator, S. monticola, S. ochracea, Sphenomorphus cryptotis and S. indicus. Our new findings increase the species number of skinks (Scincidae) to nine in Dien Bien Province and to 14 in Son La Province. We also provide additional natural history data of aforementioned species. PMID:25698899

  17. Silurian and Devonian in Vietnam—Stratigraphy and facies

    NASA Astrophysics Data System (ADS)

    Thanh, Tống Duy; Phương, Tạ Hoàng; Janvier, Philippe; Hùng, Nguyễn Hữu; Cúc, Nguyễn Thị Thu; Dương, Nguyễn Thùy

    2013-09-01

    Silurian and Devonian deposits in Viet Nam are present in several zones and regions, including Quang Ninh, East Bac Bo, and West Bac Bo Zones of the Bac Bo Region, the Dien Bien-Nghe An and Binh Tri Thien Zones of the Viet-Lao Region, and the South Trung Bo, and Western Nam Bo Zones of the South Viet Nam Region (Fig. 1). The main lithological features and faunal composition of the Silurian and Devonian Units in all these zones are briefly described. The Silurian consists of deep-water deposits of the upper parts of the Co To and Tan Mai Formations in the Quang Ninh Zone, the upper parts of the Phu Ngu Formation in the East Bac Bo Zone and the upper parts of the Long Dai and Song Ca Formations in the Viet-Lao Region. Shallow water facies Silurian units containing benthic faunas are more widely distributed, including the upper part of the Sinh Vinh and Bo Hieng Formations in the West Bac Bo Zone, the Kien An Formation in the Quang Ninh Zone, and, in the Viet-Lao Region, the Dai Giang Formation and the upper part of the Tay Trang Formation. No Lower and Middle Devonian deposits indicate deep water facies, but they are characterized by different shallow water facies. Continental to near shore, deltaic facies characterize the Lower Devonian Song Cau Group in the East Bac Bo Zone, the Van Canh Formation in the Quang Ninh Zone, and the A Choc Formation in the Binh Tri Thien Zone. Similar facies also occur in the Givetian Do Son Formation of the Quang Ninh Zone, and the Tan Lap Formation in the East Bac Bo Zone, and consist of coarse terrigenous deposits—cross-bedded conglomerates, sandstone, etc. Most Devonian units are characterized by shallow marine shelf facies. Carbonate and terrigenous-carbonate facies dominate, and terrigenous facies occur in the Lower and Middle Devonian sections in some areas only. The deep-water-like facies is characteriztic for some Upper Devonian formations in the Bac Bo (Bang Ca and Toc Tat Formations) and Viet-Lao Regions (Thien Nhan and

  18. Effect of ultimate pH on postmortem myofibrillar protein degradation and meat quality characteristics of Chinese Yellow crossbreed cattle.

    PubMed

    Li, Peng; Wang, Tiantian; Mao, Yanwei; Zhang, Yimin; Niu, Lebao; Liang, Rongrong; Zhu, Lixian; Luo, Xin

    2014-01-01

    This paper describes the complex effects of postmortem ultimate pH (pHu) on Chinese Yellow crossbreed cattle quality during postmortem ageing and provides an explanation of how pHu affects beef tenderness. High pHu beef had the highest initial tenderness (P < 0.05) compared with other groups at 1 day postmortem. Intermediate and low pHu beef had similar initial WBSF at 1 day postmortem, but intermediate pHu beef had slower tenderization rate than low pHu beef (P < 0.05). Purge loss, cooking loss, L*, a*, and b* values decreased with increasing pHu during ageing (P < 0.05). Myofibril fragmentation index (MFI) was higher in high pHu beef than intermediate and low pHu beef throughout ageing (P < 0.05). Protein degradation studies found that desmin and troponin-T appeared degraded within 0.5 h postmortem for high and low pHu beef, compared to >2 days for intermediate pHu beef. Overall, Chinese Yellow crossbred cattle tenderness is related to pHu, which may be affected by proteolytic enzymatic activity. Therefore, pHu may be used to predict beef tenderness and other quality characteristics during postmortem ageing. To achieve consistent tenderness, different ageing times should be used, depending on pHu. PMID:25197695

  19. Effect of Ultimate pH on Postmortem Myofibrillar Protein Degradation and Meat Quality Characteristics of Chinese Yellow Crossbreed Cattle

    PubMed Central

    Wang, Tiantian; Mao, Yanwei; Zhang, Yimin; Niu, Lebao; Liang, Rongrong; Zhu, Lixian; Luo, Xin

    2014-01-01

    This paper describes the complex effects of postmortem ultimate pH (pHu) on Chinese Yellow crossbreed cattle quality during postmortem ageing and provides an explanation of how pHu affects beef tenderness. High pHu beef had the highest initial tenderness (P < 0.05) compared with other groups at 1 day postmortem. Intermediate and low pHu beef had similar initial WBSF at 1 day postmortem, but intermediate pHu beef had slower tenderization rate than low pHu beef (P < 0.05). Purge loss, cooking loss, L*, a*, and b* values decreased with increasing pHu during ageing (P < 0.05). Myofibril fragmentation index (MFI) was higher in high pHu beef than intermediate and low pHu beef throughout ageing (P < 0.05). Protein degradation studies found that desmin and troponin-T appeared degraded within 0.5 h postmortem for high and low pHu beef, compared to >2 days for intermediate pHu beef. Overall, Chinese Yellow crossbred cattle tenderness is related to pHu, which may be affected by proteolytic enzymatic activity. Therefore, pHu may be used to predict beef tenderness and other quality characteristics during postmortem ageing. To achieve consistent tenderness, different ageing times should be used, depending on pHu. PMID:25197695

  20. Between ethylene and polyenes--the non-adiabatic dynamics of cis-dienes.

    PubMed

    Kuhlman, Thomas S; Glover, William J; Mori, Toshifumi; Møller, Klaus B; Martínez, Todd J

    2012-01-01

    Using Ab Initio Multiple Spawning (AIMS) with a Multi-State Multi-Reference Perturbation theory (MS-MR-CASPT2) treatment of the electronic structure, we have simulated the non-adiabatic excited state dynamics of cyclopentadiene (CPD) and 1,2,3,4-tetramethyl-cyclopentadiene (Me4-CPD) following excitation to S1. It is observed that torsion around the carbon-carbon double bonds is essential in reaching a conical intersection seam connecting S1 and S0. We identify two timescales; the induction time from excitation to the onset of population transfer back to S0 (CPD: -25 fs, Me4-CPD: -71 fs) and the half-life of the subsequent population transfer (CPD: -28 fs, Me4-CPD: -48 fs). The longer timescales for Me4-CPD are a kinematic consequence of the inertia of the substituents impeding the essential out-of-plane motion that leads to the conical intersection seam. A bifurcation is observed on S1 leading to population transfer being attributable, in a 5 : 2 ratio for CPD and 7 : 2 ratio for Me4-CPD, to two closely related conical intersections. Calculated time-resolved photoelectron spectra are in excellent agreement with experimental spectra validating the simulation results. PMID:23230770

  1. Bis(η(5)-penta-methyl-cyclo-penta-dien-yl)aluminium tetra-bromido-aluminate.

    PubMed

    Purdy, Andrew P; Dugger, Cherrelle; Butcher, Ray J

    2014-03-01

    The title compound, [Al(C10H15)2][AlBr4], was formed during the reduction of a mixture of Cp*AlBr2 and AlBr3. The Al(III) atoms of the two crystallographically independent cations each lie on an inversion center, and the [AlBr4](-) anions are on general positions. At 123 K, the structure exhibits disorder in two of the Br atoms of the [AlBr4](-) ion, with a ratio occupancy of 0.733 (6): 0.267 (3). In the crystal, there is possible weak hydrogen bonding between some methyl groups and Br atoms. The interactions link the moieties in a three-dimensional array. PMID:24764951

  2. An Approach to Mimicking the Sesquiterpene Cyclase Phase by Nickel-Promoted Diene/Alkyne Cooligomerization

    PubMed Central

    Holte, Dane; Götz, Daniel C. G.; Baran, Phil S.

    2012-01-01

    Artificially mimicking the cyclase phase of terpene biosynthesis inspires the invention of new methodologies, since working with carbogenic frameworks containing minimal functionality limits the chemist’s toolbox of synthetic strategies. For example, the construction of terpene skeletons from five-carbon building blocks would be an exciting pathway to mimic in the laboratory. Nature oligomerizes, cyclizes, and then oxidizes γ,γ-dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP) to all of the known terpenes. Starting from isoprene, the goal of this work was to mimic Nature’s approach for rapidly building molecular complexity. In principle, the controlled oligomerization of isoprene would drastically simplify the synthesis of terpenes used in the medicine, perfumery, flavor, and materials industries. This article delineates our extensive efforts to cooligomerize isoprene or butadiene with alkynes in a controlled fashion by zero-valent nickel catalysis building off the classic studies by Günther Wilke and coworkers. PMID:22229741

  3. An approach to mimicking the sesquiterpene cyclase phase by nickel-promoted diene/alkyne cooligomerization.

    PubMed

    Holte, Dane; Götz, Daniel C G; Baran, Phil S

    2012-01-20

    Artificially mimicking the cyclase phase of terpene biosynthesis inspires the invention of new methodologies, since working with carbogenic frameworks containing minimal functionality limits the chemist's toolbox of synthetic strategies. For example, the construction of terpene skeletons from five-carbon building blocks would be an exciting pathway to mimic in the laboratory. Nature oligomerizes, cyclizes, and then oxidizes γ,γ-dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP) to all of the known terpenes. Starting from isoprene, the goal of this work was to mimic Nature's approach for rapidly building molecular complexity. In principle, the controlled oligomerization of isoprene would drastically simplify the synthesis of terpenes used in the medicine, perfumery, flavor, and materials industries. This article delineates our extensive efforts to cooligomerize isoprene or butadiene with alkynes in a controlled fashion by zerovalent nickel catalysis building off the classic studies by Wilke and co-workers. PMID:22229741

  4. Macrocyclic polyenynes: a stereoselective route to vinyl-ether-containing skipped diene systems.

    PubMed

    Ronson, Thomas O; Voelkel, Martin H H; Taylor, Richard J K; Fairlamb, Ian J S

    2015-05-11

    The stereoselective synthesis of a challenging macrocyclic polyene scaffold, containing a sensitive vinyl ether motif, has been accomplished using O,C-dilithiation/selective C-alkylation, Pd-catalysed etherification and Wittig reactions as key steps. An end-game macrocyclisation strategy employed a regio- and stereoselective Stille cross-coupling using Pd(Br)(N-Succ)(AsPh3)2 (AsCat) as the precatalyst. PMID:25891970

  5. EPDM polymers with intermolecular asymmetrical molecular weight, crystallinity and diene distribution

    SciTech Connect

    Datta, S.; Cheremishinoff, N.P.; Kresge, E.N.

    1993-12-31

    Rapid extrusion of EPDM elastomers require low viscosity and thus low molecular weights for the polymer. Efficient vulcanization of these elastomers requires network perfection and thus high molecular weights for the polymer. The benefits of these apparently mutually exclusive goals is important in uses of EPDM elastomers which require extrusion of profiles which are later cured. This paper shows that by introducing simultaneously asymmetry in the distribution of molecular weights, crystallinity and vulcanizable sites these apparently contradictory goals can be resolved. While these polymers cannot be made from a single Ziegler polymerization catalyst, the authors show the synthesis of these model EPDM polymers by blending polymers with very different molecular weights, ethylene and ENB contents. These blends can be rapidly extruded without melt fracture and can be cured to vulcanizates which have excellent tensile properties.

  6. Nazarov reactions intercepted by (4 + 3) cycloadditions with oxygen-substituted dienes.

    PubMed

    LeFort, François M; Mishra, Vinayak; Dexter, Graham D; Morgan, Timothy D R; Burnell, D Jean

    2015-06-01

    The oxyallyl cation intermediate from the Lewis acid mediated Nazarov reaction of an allenyl vinyl ketone was intercepted by acyclic, 2-silyloxy-substituted butadienes by highly regioselective (4 + 3) cycloadditions. Stereoselectivity was often modest, but in some instances steric interactions were responsible for high selectivity. The results are consistent with concerted (4 + 3) cycloadditions. In many instances, the (4 + 3) products were susceptible to fragmentation or rearrangement in the presence of the Lewis acid. PMID:25984922

  7. World heritage site - Bien du Patrimoine Mondial - Kluane/Wrangell-St. Elias/Glacier Bay/Tatshenshini-Alsek

    USGS Publications Warehouse

    Labay, Keith A.; Wilson, Frederic H.

    2004-01-01

    The four parks depicted on this map make up a single World Heritage Site that covers 24.3 million acres. Together, they comprise the largest internationally protected land-based ecosystem on the planet. The United Nations Educational, Scientific and Cultural Organization (UNESCO) established the World Heritage Program in 1972 for the identification and protection of the world?s irreplaceable natural and cultural resources. World Heritage Sites are important as storehouses of memory and evolution, as anchors for sustainable tourism and community, and as laboratories for the study and understanding of the earth and culture. This World Heritage Site protects the prominent mountain ranges of Kluane, Wrangell, Saint Elias, and Chugach. It includes many of the tallest peaks on the continent, the world's largest non-polar icefield, extensive glaciers, vital watersheds, and expanses of dramatic wilderness. [Les quatre parcs figurant sur cette carte ne constituent qu?un seul site du patrimoine mondial recouvrant plus de 99 millions de km2, ce qui en fait le plus grand ecosysteme terrestre protege par loi internationale. En 1972, L?UNESCO (l?organisation des Nations Unies pour les sciences, l'education et la culture) a etabli le programme du patrimoine mondial afin d?identifier et de proteger les ressources naturelles et culturelles irremplacables de notre plan?te. Si les sites du patrimoine mondial sont si importants c'est parce qu'ils representent a la fois des livres ouverts sur l?histoire de la Terre, le point de depart du tourisme durable et du developpement des collectivites, des laboratoires pour etudier et comprendre la nature et la culture. Ce site du patrimoine mondial assure la protection des chaines de montagnes de Kluane, Wrangell, Saint Elias, et Chugach. On y trouve plusieurs des plus hauts sommets du continent, le plus grand champ de glace non-polaire du monde, d?immenses glaciers, des bassins hydrologiques essentiels, et de la nature sauvage a perte de vue.

  8. Canada's Kids: Thriving? Or Just Surviving? = Les enfants du Canada: Se developpent-ils bien ou vivotent-ils simplement?

    ERIC Educational Resources Information Center

    McCloskey, Donna, Ed.

    1997-01-01

    This quarterly journal issue (in English and French versions) includes the following articles: (1) "Canada's Kids: Thriving? Or Just Surviving?" (McCloskey, Donna), an overview of the latest research on the well-being of Canada's children; (2) "The Fence at the Edge of the Cliff: Approaching Family Policy in Canada" (Mirabelli, Alan), which…

  9. A cocrystal of 3α-hy­droxy­tirucalla-8,24-dien-21-oic acid and 3β-fluoro­tirucalla-7,24-dien-21-oic acid (0.897:0.103)

    PubMed Central

    Yousuf, S.; Kamdem, R. S. T.; Wafo, P.; Ngadjui, B. T.; Fun, Hoong-Kun

    2011-01-01

    The title compound, 0.897C30H48O3.0.103C30H47O2F is a co-crystal of two triterpenes isolated from the resin of Canarium schweinfurthiiand Engl. Both triterpenes consists of four trans-fused rings having chair/half-chair/half-chair and envelope conformations. The mol­ecular conformations are stabilized by intra­molecular C—H⋯O hydrogen bonds, forming rings of S(7) graph-set motif. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O and C—H⋯O inter­actions, forming sheets parallel to (001). All atoms. excepting the axially-oriented hydroxyl group in the major component and the equatorially-oriented fluorine atom in the minor component, are overlapping. PMID:21754032

  10. A cocrystal of 3α-hy-droxy-tirucalla-8,24-dien-21-oic acid and 3β-fluoro-tirucalla-7,24-dien-21-oic acid (0.897:0.103).

    PubMed

    Yousuf, S; Kamdem, R S T; Wafo, P; Ngadjui, B T; Fun, Hoong-Kun

    2011-04-01

    The title compound, 0.897C(30)H(48)O(3).0.103C(30)H(47)O(2)F is a co-crystal of two triterpenes isolated from the resin of Canarium schweinfurthiiand Engl. Both triterpenes consists of four trans-fused rings having chair/half-chair/half-chair and envelope conformations. The mol-ecular conformations are stabilized by intra-molecular C-H⋯O hydrogen bonds, forming rings of S(7) graph-set motif. In the crystal, mol-ecules are linked by inter-molecular O-H⋯O and C-H⋯O inter-actions, forming sheets parallel to (001). All atoms. excepting the axially-oriented hydroxyl group in the major component and the equatorially-oriented fluorine atom in the minor component, are overlapping. PMID:21754032

  11. Diels-Alder Trapping of Photochemically Generated Dienes with Acrylic Esters: A Novel Approach to Photocured Polymer Film Development

    NASA Technical Reports Server (NTRS)

    Ilhan, Faysal; Tyson, Daniel S.; Smith, Deedee; Meador, Mary Ann; Meador, Michael A.

    2004-01-01

    Diels-Alder cycloadditions have often been utilized in polymer synthesis as an alternative to condensation reactions. In our earlier efforts, we developed a new method for the preparation of linear aromatic polyimides, which employs o-quionodimethanes (o-QDMs), generated by a well-known photochemical reaction: the photoenolization of o-methylphenyl ketones. Photolysis of o-methylbenzophenone 1 produces hydroxy-o-quino- diemthane 2, which can be trapped with dienophiles, such as dimethyl acetylenedicarboxylate, to efficiently yield the corresponding cycloadduct (Scheme 1). Here we extend this approach to a novel photocuring process for development of polymer films. We synthesized a series of molecules with multi o-mehtylphenyl ketone functionalities. We further investigated these molecules as photoreactive monomers to obtain polyester films through Diels-Alder cycloadditions.

  12. Mechanistic interpretation of selective catalytic hydrogenation and isomerization of alkenes and dienes by ligand deactivated Pd nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhu, Jie S.; Shon, Young-Seok

    2015-10-01

    Unsupported thiolate-capped palladium nanoparticle catalysts are found to be highly substrate-selective for alkene hydrogenation and isomerization. Steric and poisoning effects from thiolate ligands on the nanoparticle surface control reactivity and selectivity by influencing alkene adsorption and directing either di-σ or mono-σ bond formation. The presence of overlapping p orbitals and α protons in alkenes greatly influences the catalytic properties of deactivated palladium nanoparticles leading to easily predictable hydrogenation or isomerization products.Unsupported thiolate-capped palladium nanoparticle catalysts are found to be highly substrate-selective for alkene hydrogenation and isomerization. Steric and poisoning effects from thiolate ligands on the nanoparticle surface control reactivity and selectivity by influencing alkene adsorption and directing either di-σ or mono-σ bond formation. The presence of overlapping p orbitals and α protons in alkenes greatly influences the catalytic properties of deactivated palladium nanoparticles leading to easily predictable hydrogenation or isomerization products. Electronic supplementary information (ESI) available: Supplementary figures, methods, materials, and characterization data. See DOI: 10.1039/c5nr05090a

  13. 11,20-Dihy­droxy-3-oxopregna-1,4-dien-21-oic acid monohydrate

    PubMed Central

    Guo, Zhanqiang; Tang, Shengan; Duan, Hongquan

    2011-01-01

    The title compound, C21H28O5·H2O, is the hydrate of a steroid derivative and was obtained by degradation of solid prednisolone sodium phosphate. The six C atoms in ring A are nearly co-planar with a mean deviation of 0.015 Å. Rings B and C are both in chair conformations, while ring D has an envelope form. In the crystal, inter­molecular O—H⋯O hydrogen-bonding inter­actions occur between the hy­droxy groups, carbonyl O atoms and solvent water mol­ecules, resulting in an overall three-dimensional structure. PMID:21754697

  14. From supramolecular polymersomes to stimuli-responsive nano-capsules based on poly(diene-b-peptide) diblock copolymers

    NASA Astrophysics Data System (ADS)

    Chécot, F.; Lecommandoux, S.; Klok, H.-A.; Gnanou, Y.

    2003-01-01

    This paper discusses the self-assembly of block copolymers into vesicular morphology. After a brief state of art of the field, a system based on an amphiphilic poly(butadiene)-b-poly(γ-L-glutamic acid) (PB-b-PGA) diblock copolymer in aqueous solution is discussed in detail. The aggregation behavior of this block copolymer has been investigated by means of fluorescence spectroscopy, dynamic (DLS) and static (SLS) light scattering as well as transmission electron microscopy (TEM). The diblock copolymer was found to form well-defined vesicles in water. The size of these so-called polymersomes or peptosomes could be reversibly manipulated as a function of both pH and ion strength. Depending on the pH of the aqueous solution, the hydrodynamic radii of these vesicles were found to vary from 100 nm to 150 nm. By cross-linking the 1,2-vinyl double bonds present in the polybutadiene block, the ability to transform a transient supramolecular self-organized aggregate into a permanent “shape-persistent stimuli-responsive nanoparticle” has been demonstrated.

  15. 3,8-Dimethyl-4,7-diaza-deca-3,7-diene-2,9-dione dioxime.

    PubMed

    Achiwawanich, Supakit; Duangtongyou, Tanwawan; Pakawatchai, Chaveng; Siripaisarnpipat, Sutatip

    2010-01-01

    The complete mol-ecule of the title compound, C(10)H(18)N(4)O(2), is generated by a crystallographic inversion centre at the mid-point of the central C-C bond. The two oxime groups have an E configuration. In the crystal, mol-ecules are linked through inter-molecular O-H⋯N hydrogen bonds. PMID:21522645

  16. 3,8-Dimethyl-4,7-diaza­deca-3,7-diene-2,9-dione dioxime

    PubMed Central

    Achiwawanich, Supakit; Duangtongyou, Tanwawan; Pakawatchai, Chaveng; Siripaisarnpipat, Sutatip

    2011-01-01

    The complete mol­ecule of the title compound, C10H18N4O2, is generated by a crystallographic inversion centre at the mid-point of the central C—C bond. The two oxime groups have an E configuration. In the crystal, mol­ecules are linked through inter­molecular O—H⋯N hydrogen bonds. PMID:21522645

  17. Observing the orbital ordering of Ti(III) ions in catalysts for the polymerization of diene compounds

    NASA Astrophysics Data System (ADS)

    Biktagirov, V. V.; Anufrienko, V. F.; Biktagirova, E. V.

    2016-02-01

    The orbital ordering of Ti(III) ions is observed via EPR spectroscopy for the catalytic system TiCl4 + TIBA in an isopentane solution with an excess of organoaluminum compound. A model of the alternating ground states of 3 d 1 ions ( d xy and d_{z^2 } is proposed for the ordered structures. Ti(III) ions with the d xy ground states are mono- and dialkylated.

  18. 17β-Hy­droxy-17α-methyl­androsta-1,4-dien-3-one

    PubMed Central

    Karpinska, Jolanta; Erxleben, Andrea; McArdle, Patrick

    2013-01-01

    The title compound, C20H28O2, is a steroid with strong anabolic properties. The present solvent-free form crystallizes with two mol­ecules per asymmetric unit. In the crystal, both mol­ecules are involved in the formation of O—H⋯O hydrogen-bonded chains which extend along the b-axis direction. PMID:23476441

  19. Erratum: Di-μ-nitrosyl-bis-[(η-penta-methyl-cyclo-penta-dien-yl)ruthenium(0)](Ru-Ru). Corrigendum.

    PubMed

    Pearsal, Matthew; Gembicky, Milan; Dominiak, Paulina; Larsen, Anna; Coppens, Philip

    2010-01-01

    The acknowledgement in the paper by Pearsal, Gembicky, Dominiak, Larsen & Coppens [Acta Cryst. (2007), E63, m2596] is extended and an omitted reference is added.[This corrects the article DOI: 10.1107/S1600536807045321.]. PMID:21578980

  20. 77 FR 64102 - Frozen Warmwater Shrimp From the Socialist Republic of Vietnam: Amended Final Results and Partial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ... FR 55800 (September 11, 2012) (``Final Results''). On September 17, 2012, the Minh Phu Group,\\2\\ Phu... of Vietnam: Preliminary Results of Administrative Review, 77 FR 13547 (March 7, 2012) (``Preliminary....; Versaggi Shrimp Co.; and Craig Wallis. \\8\\ See Preliminary Results, 77 FR at 13548. These amended...

  1. Katimavik Participant's Manual, Book VIII, Nutrition and Well-Being = Katimavik manuel du participant, cahier VIII, l'alimentation et le bien-etre.

    ERIC Educational Resources Information Center

    Crelinsten, Michael, Ed.

    The bilingual student manual focuses on the nutrition and well-being learning activity portion of Katimavik, a nine-month volunteer community service and experiential learning program for 17 to 21 year old Canadians. Providing participants with basic information and tools to assess and improve nutritional states and tie nutrition concerns into a…

  2. Grassroots Action Research and the Greater Good (La investigación acción de base y el bien mayor)

    ERIC Educational Resources Information Center

    Rainey, Isobel

    2011-01-01

    This study examines the action research topics and topic preferences of two groups of grassroots teachers: active researchers, and potential researchers. The analysis of the topics appears to indicate that, over the past decade, action research at the teaching of English at the grassroots level to speakers of other languages has been principally…

  3. Selective hydrogenation of dienes and alkynes to alkenes in the presence of products of the reaction of bis-. pi. -allylpalladium chloride with amines

    SciTech Connect

    Cherkashin, G.M.; Shuikina, L.P.; Parenago, O.P.; Frolov, V.M.

    1987-06-01

    The authors have shown that the interaction of bis-..pi..-allylpalladium chloride with primary or secondary amines containing alkyl groups of substantial size (octyl- or dioctylamine) in toluene medium leads to the formation of palladium complexes active in the homogeneous catalytic hydrogenation of unsaturated hydrocarbons.

  4. Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates

    PubMed Central

    Edmunds, Michael; Raheem, Mohammed Abdul; Boutin, Rebecca; Tait, Katrina

    2016-01-01

    Summary Palladium-catalyzed ring-opening reactions of C1 substituted 7-oxanorbornadiene derivatives with aryl iodides were investigated. The optimal conditions for this reaction were found to be PdCl2(PPh3)2, ZnCl2, Et3N and Zn in THF. Both steric and electronic factors played a role in the outcome of the reaction as increasing the steric bulk on the bridgehead carbon decreased the yield. These reactions were found to be highly regioselective, giving only one of the two possible regioisomers in all cases. A diverse collection of novel, highly substituted biphenyl derivatives were obtained. PMID:26977182

  5. Crystal structure of 15,16-ep-oxy-7β,9α-di-hydroxy-labdane-13(16),14-dien-6-one.

    PubMed

    Singh, Vikram Dev; Kamni; Amina, Musarat; Al-Musayeib, Nawal; Anthal, Sumati; Kant, Rajni

    2015-07-01

    In the title mol-ecule, C20H30O4, both cyclo-hexane rings adopt chair conformations. In the crystal, mol-ecules are connected by O-H⋯O hydrogen bonds forming chains along [100]. In addtion, an intra-molecular O-H⋯O hydrogen bond forms an S(5) ring. PMID:26279920

  6. Complexation of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-diene dithiocyanate with nickel (II) acetate

    NASA Astrophysics Data System (ADS)

    Ishak, Nur Iliyani Mohd; Yamin, Bohari M.

    2013-11-01

    The complexation of nickel acetate with tetraaza involves deprotonation of protonated amine nitrogen to form neutral ligand coordinated to the nickel via the four nitrogen atom. The dication complex is paired with thiocyanate anions. The complex was characterized by elemental analysis, UV-VIS and FTIR spectroscopic method. The crystal structure of nickel complex characterized by X-Ray crystallography and adopts square planar geometry.

  7. CATALYZED CYCLIZATION OF [ALPHA],[OMEGA]-DIENES: A VERSATILE PROTOCOL FOR THE SYNTHESIS OF FUNCTIONALIZED CARBOCYCLIC AND HETEROCYCLIC COMPOUNDS. (R826120)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  8. Processable, high temperature polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and bis-dienes

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.

    1988-01-01

    1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene reacts with various anthracene end-capped polyimide oligomers to form Diels-Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21,000 to 32,000. These resins exhibit lower weight loss in air than in nitrogen. This is suggested to be due to dehydration (loss of water ranges from 2 to 5 percent) at temperatures of 390 to 400 C to give thermooxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermooxidative stability, the polymers have potential as processable, matrix resins for high temperature composite applications.

  9. Addition polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and Bis-dienes: Processable resins for high temperature application

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.

    1987-01-01

    1,4,5,8-Tetrahydro-1,4;5,8-diepoxyanthracene reacts with various anthracene endcapped polyimide oligomers to form Diels-Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21,000 to 32,000. Interestingly, these resins appear to be more stable in air then in nitrogen. This is shown to be due to a unique dehydration (loss of water ranges from 2 to 5 percent) at temperatures of 390 to 400 C to give thermo-oxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermo-oxidative stability, the polymers have potential as processible, matrix resins for high temperature composite applications.

  10. (1E,3E)-1,4-Bis(4-meth­oxy­phen­yl)buta-1,3-diene

    PubMed Central

    Narayan, Gopinathan; Rath, Nigam P.; Das, Suresh

    2010-01-01

    The title compound, C18H18O2, which exhibits blue emission in the solid state, is an inter­mediate in the preparation of liquid crystals and polymers. The mol­ecule is located on an inversion centre. In the crystal, mol­ecules are arranged in a herringbone motif. PMID:21587646

  11. Diversification of ortho-Fused Cycloocta-2,5-dien-1-one Cores and Eight- to Six-Ring Conversion by σ Bond C-C Cleavage.

    PubMed

    Eccleshare, Lee; Lozada-Rodríguez, Leticia; Cooper, Phillippa; Burroughs, Laurence; Ritchie, John; Lewis, William; Woodward, Simon

    2016-08-22

    Sequential treatment of 2-C6 H4 Br(CHO) with LiC≡CR(1) (R(1) =SiMe3 , tBu), nBuLi, CuBr⋅SMe2 and HC≡CCHClR(2) [R(2) =Ph, 4-CF3 Ph, 3-CNPh, 4-(MeO2 C)Ph] at -50 °C leads to formation of an intermediate carbanion (Z)-1,2-C6 H4 {CA (=O)C≡CB R(1) }{CH=CH(CH(-) )R(2) } (4). Low temperatures (-50 °C) favour attack at CB leading to kinetic formation of 6,8-bicycles containing non-classical C-carbanion enolates (5). Higher temperatures (-10 °C to ambient) and electron-deficient R(2) favour retro σ-bond C-C cleavage regenerating 4, which subsequently closes on CA providing 6,6-bicyclic alkoxides (6). Computational modelling (CBS-QB3) indicated that both pathways are viable and of similar energies. Reaction of 6 with H(+) gave 1,2-dihydronaphthalen-1-ols, or under dehydrating conditions, 2-aryl-1-alkynylnaphthlenes. Enolates 5 react in situ with: H2 O, D2 O, I2 , allylbromide, S2 Me2 , CO2 and lead to the expected C-E derivatives (E=H, D, I, allyl, SMe, CO2 H) in 49-64 % yield directly from intermediate 5. The parents (E=H; R(1) =SiMe3 , tBu; R(2) =Ph) are versatile starting materials for NaBH4 and Grignard C=O additions, desilylation (when R(1) =SiMe) and oxime formation. The latter allows formation of 6,9-bicyclics via Beckmann rearrangement. The 6,8-ring iodides are suitable Suzuki precursors for Pd-catalysed C-C coupling (81-87 %), whereas the carboxylic acids readily form amides under T3P® conditions (71-95 %). PMID:27452351

  12. N′-[(1E,2E)-3,7-Dimethyl­octa-2,6-dien-1-yl­idene]pyridine-4-carbohydrazide

    PubMed Central

    Bhat, Mashooq A.; Abdel-Aziz, Hatem A.; Ghabbour, Hazem A.; Hemamalini, Madhukar; Fun, Hoong-Kun

    2012-01-01

    In the title compound, C16H21N3O, the mol­ecule adopts an E conformation about the central C=N double bond. The 2-methyl­pent-2-ene group is disordered over two sets of sites, with a refined occupancy ratio of 0.785 (8):0.215 (8). The dihedral angle between the essentially planar [the r.m.s. value for the major component is 0.021 (7) and its maximum deviation is 0.025 (4) Å; the r.m.s. value for the minor component is 0.03 (4) and its maximum deviation is 0.05 (3) Å] major and minor components of the 2-methyl­but-2-ene group is 35.9 (13)°. In the crystal, C—H⋯O and N—H⋯O hydrogen bonds link the molecules, with the same O atom acting as the acceptor. This results in C 1 1(4) and C 1 1(5) [001] chains. PMID:22606092

  13. The Isomerization of Δ5-Androstene-3,17-dione by the Human Glutathione Transferase A3-3 Proceeds via a Conjugated Heteroannular Diene Intermediate*

    PubMed Central

    Daka, Jonathan L.; Achilonu, Ikechukwu; Dirr, Heini W.

    2014-01-01

    The seemingly simple proton abstraction reactions underpin many chemical transformations, including isomerization reactions, and are thus of immense biological significance. Despite the energetic cost, enzyme-catalyzed proton abstraction reactions show remarkable rate enhancements. The pathways leading to these accelerated rates are numerous and on occasion partly enigmatic. The isomerization of the steroid Δ5-androstene-3,17-dione by the glutathione transferase A3-3 in mammals was investigated to gain insight into the mechanism. Particular emphasis was placed on the nature of the transition state, the intermediate suspected of aiding this process, and the hydrogen bonds postulated to be the stabilizing forces of these transient species. The UV-visible detection of the intermediate places this species in the catalytic pathway, whereas fluorescence spectroscopy is used to obtain the binding constant of the analog intermediate, equilenin. Solvent isotope exchange reveals that proton abstraction from the substrate to form the intermediate is rate-limiting. Analysis of the data in terms of the Marcus formalism indicates that the human glutathione transferase A3-3 lowers the intrinsic kinetic barrier by 3 kcal/mol. The results lead to the conclusion that this reaction proceeds through an enforced concerted mechanism in which the barrier to product formation is kinetically insignificant. PMID:25248748

  14. Diels-Alder Cycloadditions: A MORE Experiment in the Organic Laboratory Including a Diene Identification Exercise Involving NMR Spectroscopy and Molecular Modeling

    ERIC Educational Resources Information Center

    Shaw, Roosevelt; Severin, Ashika; Balfour, Miguel; Nettles, Columbus

    2005-01-01

    Two Diels-Alder reactions are described that are suitable for a MORE (microwave-induced organic reaction enhanced) experiment in the organic chemistry laboratory course. A second experiment in which the splitting patterns of the vinyl protons in the nuclear magnetic resonance (NMR) spectra of two MORE adducts are used in conjunction with molecular…

  15. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  16. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  17. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  18. A purple odyssey: synthesis and structure of 3-amino-4-hy-droxy-6-oxo-cyclo-hexa-2,4-dien-1-iminium chloride monohydrate.

    PubMed

    Plater, M John; Harrison, William T A

    2016-05-01

    In the cation of the title hydrated mol-ecular salt, C6H7N2O2 (+)·Cl(-)·H2O, the six-membered ring shows unequal bond lengths consistent with delocalization of electrons over two separate 6π systems with single bonds between them. In the crystal, the components are linked by N-H⋯Cl, N-H⋯O, O-H⋯Cl and O-H⋯O hydrogen bonds, generating double layers propagating in (100). PMID:27307999

  19. Complexation of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-diene dithiocyanate with nickel (II) acetate

    SciTech Connect

    Ishak, Nur Iliyani Mohd; Yamin, Bohari M.

    2013-11-27

    The complexation of nickel acetate with tetraaza involves deprotonation of protonated amine nitrogen to form neutral ligand coordinated to the nickel via the four nitrogen atom. The dication complex is paired with thiocyanate anions. The complex was characterized by elemental analysis, UV-VIS and FTIR spectroscopic method. The crystal structure of nickel complex characterized by X-Ray crystallography and adopts square planar geometry.

  20. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  1. 6-(2-Hydroxy­anilinomethyl­ene)-4-nitro­cyclo­hexa-2,4-dien-1-one

    PubMed Central

    Böhme, Uwe; Fels, Sabine

    2008-01-01

    The molecule of the title compound, C13H10N2O4, is nearly planar with a dihedral angle between the two aromatic rings of 2.24 (9)°. The NH group forms an intramolecular hydrogen bond with the carbonyl O atom. The mol­ecules form dimers about inversion centers in the crystal structure via inter­molecular O—H⋯O hydrogen bonds. PMID:21200741

  2. Effect of chronic aluminum exposure on the levels of conjugated dienes and enzymatic antioxidants in hippocampus and whole brain of rat

    SciTech Connect

    Gupta, A.; Shukla, G.S.

    1995-11-01

    The reported association between elevated tissue levels of aluminum (Al) and certain human neurological disorders have evoked increasing attention on the neurotoxic effects of aluminum. High levels of Al have been reported in hippocampal neurons comprising neurofibrillary tangles in senile dementia of Alzheimer`s type, amyotropic lateral sclerosis and Parkinsonian dementia of Guam. Aluminum is considered to be the causal factor for a high incidence of dialysis encephalopathy. It has been shown that the incidence of Alzheimer`s disease was higher in places with a high Al content in drinking water compared to low level areas. Varied uses of Al in pharmaceutical preparations, foods, water purification and many house-hold items have increased the risk of its exposure to general population. The exposure may be as high as 500 mg/kg/day in children with uremia who are treated with Al containing phosphate binding gels. Aluminum ingestion in humans and experimental animals have been reported to produce behavioural dysfunctions. The mechanism of al neurotoxicity is not understood at present. Attempts made in this direction have reported its interaction with blood-brain barrier function, decreased membrane fluidity, glutathione depletion and increased brain lipid peroxidation. These studies indicate the possibility that oxidative stress may be one of the possible mechanisms of Al-induced neurotoxicity. Since Al has been reported to be in high concentrations in hippocampal neurons in certain neurological diseases and there is wealth of evidence implicating hippocampal impairment and memory dysfunction, we attempted to investigate the effect of chronic Al intoxication on the status of enzymatic antioxidants and the extent of peroxidative damage in hippocampus and whole brain of rat. 16 refs., 4 figs., 1 tab.

  3. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  4. Characterization of the first-in-class T-cell-engaging bispecific single-chain antibody for targeted immunotherapy of solid tumors expressing the oncofetal protein claudin 6

    PubMed Central

    Stadler, Christiane R.; Bähr-Mahmud, Hayat; Plum, Laura M.; Schmoldt, Kathrin; Kölsch, Anne C.; Türeci, Özlem; Sahin, Ugur

    2016-01-01

    abstract The fetal tight junction molecule claudin 6 (CLDN6) is virtually absent from any normal tissue, whereas it is aberrantly and frequently expressed in various cancers of high medical need. We engineered 6PHU3, a T-cell-engaging bispecific single chain molecule (bi-(scFv)2) with anti-CD3/anti-CLDN6 specificities, and characterized its pharmacodynamic properties. Our data show that upon engagement by 6PHU3, T cells strongly upregulate cytotoxicity and activation markers, proliferate and acquire an effector phenotype. 6PHU3 exerts potent killing of cancer cells in vitro with EC50 values in the pg/mL range. Subcutaneous xenograft tumors in NSG mice engrafted with human PBMCs are eradicated by 6PHU3 treatment and survival of mice is significantly prolonged. Tumors of 6PHU3-treated mice are strongly infiltrated with activated CD4+, CD8+ T cells and TEM type cells but not Tregs and display a general activation of a mostly inflammatory phenotype. These effects are only observed upon bispecific but not monospecific engagement of 6PHU3. Together with the exceptionally cancer cell selective expression of the oncofetal tumor marker CLDN6, this provides a safeguard with regard to toxicity. In summary, our data shows that the concept of T-cell redirection combined with that of highly selective targeting of CLDN6-positive solid tumors is effective. Thus, exploring 6PHU3 for clinical therapy is warranted. PMID:27141353

  5. Impact of divergent selection for ultimate pH of pectoralis major muscle on biochemical, histological, and sensorial attributes of broiler meat.

    PubMed

    Alnahhas, N; Le Bihan-Duval, E; Baéza, E; Chabault, M; Chartrin, P; Bordeau, T; Cailleau-Audouin, E; Meteau, K; Berri, C

    2015-09-01

    The impact of divergent selection based on the ultimate pH (pHu) of pectoralis major (P. major) muscle on the chemical, biochemical, and histological profiles of the muscle and sensorial quality of meat was investigated in broiler chickens. The protein, lipid, DM, glycogen and lactate content, glycolytic potential, proteolysis, lipid and protein oxidation index, muscle fiber cross-sectional area, capillary density, and collagen surface were determined on the breast P. major muscle of 6-wk-old broilers issued from the high-pHu (pHu+) and low-pHu (pHu-) lines. Sensory attributes were also evaluated on the breast (roasted or grilled) and thigh (roasted) meat of the 2 lines. Protein, lipid, and DM content of P. major muscle were not affected by selection ( > 0.05). However, the P. major muscle of the pHu+ line was characterized by lower residual glycogen (-16%; ≤ 0.001) and lactate (-14%; ≤ 0.001) content and lower glycolytic potential (-14%; ≤ 0.001) compared with the pHu- line. Although the average cross-sectional area of muscle fibers and surface occupied by collagen were similar ( > 0.05) in both lines, fewer capillaries per fiber (-15%; ≤ 0.05) were observed in the pHu+ line. The pHu+ line was also characterized by lower lipid oxidation (thiobarbituric acid reactive substance index: -23%; ≤ 0.05) but protein oxidation and proteolysis index were not different ( > 0.05) between the 2 lines. At the sensory level, selection on breast muscle pHu mainly affected the texture of grilled and roast breast meat, which was judged significantly more tender ( ≤ 0.001) in the pHu+ line, and the acid taste, which was less pronounced in the roasted breast meat of the pHu+ line ( ≤ 0.002). This study highlighted that selection based on pHu does not affect the chemical composition and structure of breast meat. However, by modifying muscle blood supply and glycogen turnover, it affects meat acidity and oxidant status, both of which are likely to contribute to the large

  6. Early on-line classification of beef carcasses based on ultimate pH by near infrared spectroscopy.

    PubMed

    Reis, Marlon M; Rosenvold, Katja

    2014-02-01

    Prediction of ultimate pH (measured 48 h post mortem; pH(u)) in beef from Visible-near infrared (VIS-NIR) spectra collected 20 to 40 min post mortem was assessed. Spectra were collected from carcasses (cows: n = 86, bulls: n = 170, steers: n = 363, and heifers: n = 38) in a commercial hot boning abattoir under routine conditions. Partial Least Squares (PLS) models showed limited accuracy with RMSE for validation equal to 0.26, 0.20 and 0.36 for the All-animals, Non-bulls and Bulls models, respectively. The pH(u)-PLS-predicted values were used to segregate carcasses as normal (pH(u)<5.8) or high (pH(u) ≥ 5.8) showing better performance, by correctly classifying at least 90% of high pH(u) carcasses. The Non-bulls model was equivalent to the current technology used in the abattoir to classify carcasses based on pH(u). Thus near infrared spectroscopy (NIRS) could be used for on-line classification of beef carcasses based on pH(u). PMID:24211544

  7. Metabolic engineering of E.coli for the production of a precursor to artemisinin, an anti-malarial drug [Chapter 25 in Manual of Industrial Microbiology and Biotechnology, 3rd edition

    SciTech Connect

    Petzold, Christopher; Keasling, Jay

    2011-07-18

    This document is Chapter 25 in the Manual of Industrial Microbiology and Biotechnology, 3rd edition. Topics covered include: Incorporation of Amorpha-4,11-Diene Biosynthetic Pathway into E. coli; Amorpha-4,11-Diene Pathway Optimization; "-Omics" Analyses for Increased Amorpha-4,11-Diene Production; Biosynthetic Oxidation of Amorpha-4,11-Diene.

  8. The Development of a Taxonomy of the Life Skills Required to Become a Balanced Self-Determined Person = Essaie de Classification des Competences Necessaires pour Devenir une Personne Autonome et Bien Equilibree.

    ERIC Educational Resources Information Center

    Smith, Paul

    Intended for use by life skills coaches and students, program evaluators, and individuals developing lesson plans and other training materials, this taxonomy includes all of the terminal performance behaviors and corresponding sub-skills required to become and function as a balanced, self-determined person who manages the problems of everyday life…

  9. Are the Kids Alright? What's Shaping the Attitudes, Values and Behaviour of our Young People? = Les enfants se portent-ils bien? Qu'est-ce qui faconne les attitudes, les valeurs et le comportement de nos jeunes?

    ERIC Educational Resources Information Center

    Theilheimer, Ish, Ed.

    1992-01-01

    This theme issue explores the behavior of teenagers. "Are the Kids Alright?" (Ish Theilheimer) develops a perspective on the subject of teen behavior, noting that a growing number of young people demonstrate discontent, alienation, aggression, violence, and antisocial behavior, and that a growing underclass of children is likely to fail. The…

  10. (μ3-Hydrido)[μ3-2-(tri-methyl-sil-yl)ethyl-idyne-κ(3) C (1):C (1):C (1)]tetra-kis-[(η(5)-cyclo-penta-dien-yl)cobalt(II)].

    PubMed

    Haehnel, Martin; Spannenberg, Anke; Rosenthal, Uwe

    2013-11-01

    In the title compound, [Co4(C5H5)4(μ3-CCH2SiMe3)(μ3-H)], the Co atoms form a distorted tetra-hedron with the ethyl-idyne moiety bridging three of the Co atoms as well as the hydrido ligand also bridging three of the Co atoms. The Co-Co bond lengths in the Co4 tetrahedron vary from 2.3844 (4) to 2.4608 (4) Å. Each Co atom is additionally η(5)-bonded to a cyclopentadienyl (Cp) anion. PMID:24454164

  11. Practical synthesis of [n]cycloparaphenylenes (n = 5, 7-12) by H2SnCl4-mediated aromatization of 1,4-dihydroxycyclo-2,5-diene precursors.

    PubMed

    Patel, Vijay Kumar; Kayahara, Eiichi; Yamago, Shigeru

    2015-04-01

    Cyclic precursors of cycloparaphenylenes (CPPs) containing 1,4-dihydroxy-2,5-cyclohexadien-1,4-diyl units are prepared by modifying a synthetic method developed by Jasti and co-workers for the synthesis of corresponding 1,4-dimethoxy derivatives. Reductive aromatization of the diyl moieties by SnCl2/2 HCl takes place under mild conditions and affords the CPPs in good yields, incorporating 5 or 7-12 phenylene units. Highly strained [5]CPP is synthesized in greater than 0.3 g scale. (119)Sn NMR spectroscopy clarifies the in situ formation of an ate complex, H2SnCl4, upon mixing a 2:1 ratio of HCl and SnCl2, which serves as a highly active reducing agent under nearly neutral conditions. When more than 2 equivalents of HCl, in relation to SnCl2, are used, acid-catalyzed decomposition of the CPP precursors takes place. The stoichiometry of HCl and SnCl2 is critical in achieving the desired aromatization reaction of highly strained CPP precursors. PMID:25753916

  12. Transmetalation from B to Rh in the course of the catalytic asymmetric 1,4-addition reaction of phenylboronic acid to enones: a computational comparison of diphosphane and diene ligands.

    PubMed

    Li, You-Gui; He, Gang; Qin, Hua-Li; Kantchev, Eric Assen B

    2015-02-14

    Transmetalation is a key elementary reaction of many important catalytic reactions. Among these, 1,4-addition of arylboronic acids to organic acceptors such as α,β-unsaturated ketones has emerged as one of the most important methods for asymmetric C-C bond formation. A key intermediate for the B-to-Rh transfer arising from quaternization on a boronic acid by a Rh-bound hydroxide (the active catalyst) has been proposed. Herein, DFT calculations (IEFPCM/PBE0/DGDZVP level of theory) establish the viability of this proposal, and characterize the associated pathways. The delivery of phenylboronic acid in the orientation suited for the B-to-Rh transfer from the very beginning is energetically preferable, and occurs with expulsion of Rh-coordinated water molecules. For the bulkier binap ligand, the barriers are higher (particularly for the phenylboronic acid activation step) due to a less favourable entropy term to the free energy, in accordance with the experimentally observed slower transmetalation rate. PMID:25422851

  13. Un mode de découverte inhabituel d'hyperparathyroïdie primaire: fractures multiples sur tumeurs brunes secondaires à un adénome parathyroïdien ectopique médiastinal

    PubMed Central

    Yassine, Asmaa; Guerboub, Ahmed Anas; Arsalane, Adil; Biyi, Abdelhamid; Moussaoui, Souad El; Belmejdoub, Ghizlaine

    2015-01-01

    La tumeur brune est une entité clinique bénigne apparaissant comme une manifestation squelettique rare de l'hyperparathyroïdie primaire. Il s'agit d'une cause inhabituelle de fractures pathologiques. Nous rapportons ici le cas clinique d'un patient âgé de 20 ans chez qui l'hyperparathyroïdie primitive a été découverte devant des tumeurs brunes multiples. PMID:26966486

  14. Crystal structure of azido­(η5-cyclo­penta­dien­yl)bis­(tri­phenyl­phosphane-κP)ruthenium(II) di­chloro­methane hemisolvate

    PubMed Central

    Hernández-Calva, Adriana; Meléndez-Balbuena, Lidia; Arroyo, Maribel; Ramírez-Monroy, Armando

    2014-01-01

    The title solvated complex, [Ru(η5-C5H5)(N3){P(C6H5)3}2]·0.5CH2Cl2, displays a typical piano-stool geometry about the RuII atom. The bond lengths and angles of the cyclo­penta­dienyl and phosphane ligands are very similar to that of the unsolvated complex [Taqui Khan et al. (1994 ▶). Acta Cryst. C50, 502–504]. The azide anion displays similar N—N distances of 1.173 (3) and 1.156 (3) Å and has an N—N—Ru angle of 119.20 (15)°, indicating a greater contribution of the canonical form Ru—N=N(+)=N(-) for the bonding situation. An intra­molecular C—H⋯N hydrogen-bonding inter­action between one ortho H atom of a phosphane ligand and the N atom coordinating to the metal is observed. A similar inter­molecular inter­action is observed between a meta H atom of a phosphane ligand and the terminal azide N atom of a neighbouring complex. Finally, two C—H⋯N inter­actions exists between the H atoms of the di­chloro­methane solvent mol­ecule and the terminal N atom of two azide anions. The solvent mol­ecule is located about a twofold rotation axis and shows disorder of the Cl atoms with an occupancy ratio of 0.62 (3):0.38 (3). PMID:25484673

  15. (2Z,4E)-1-(5-Fluoro-2-hy­droxy­phen­yl)-5-(4-fluoro­phen­yl)-3-hy­droxy­penta-2,4-dien-1-one

    PubMed Central

    Chen, Jing-Wei; He, Zhuo; Wu, Zhen; Fang, Mei-Juan; Fang, Hua

    2014-01-01

    In the title mol­ecule, C17H12F2O3, the dihedral angle between the benzene rings is 8.6 (2)°. In the crystal, two pairs of O—H⋯O hydrogen bonds connect the mol­ecules into inversion dimers. In addition, weak C—H⋯F hydrogen bonds link the dimers into a two-dimensional network parallel to (10-4). The carbonyl O atom is an acceptor for two weak intra­molecular hydrogen bonds. PMID:24527017

  16. Ameliorative Effects of Operculina turpethum and its Isolated Stigma-5,22dien-3-o-β-D-glucopyranoside on the Hematological Parameters of Male Mice Exposed to N-Nitrosodimethylamine, a Potent Carcinogen

    PubMed Central

    Sharma, Veena; Singh, Manu

    2014-01-01

    Objectives: Enormous propensity of plants to synthesize a variety of structurally diverse bioactive compounds, has made the plant kingdom a potential source of chemical constituents with various therapeutic values, including antitumor and cytotoxic activities. Blood is a good indicator to determine the physiological and pathological status of man and animal. The objective of the present study is to determine the effect of Operculina turpethum root extract and its isolated glycoside treatment on the hematological parameters in the mice with N-Nitrosodimethylamine (NDMA) induced cancer. Materials and Methods: The body weights of the animals were recorded before and after the experiment. Non-coagulated blood was tested for total erythrocyte count, total leukocyte count, hemoglobin, differential leukocyte count (DLC) and for other blood indices. Results: A significant (P < 0.01), (P < 0.001) recovery of the red blood cell and white blood cell counts, packed cell volume and hemoglobin content in the host after 21 day treatment was shown. Conclusion: These results show that the extract of Operculina turpethum is relatively safe following oral administration and have possible stimulatory effect on red blood cell production and there was dose dependent therapeutic effect. PMID:24748732

  17. Hexamethyl 13,14-dioxapenta­cyclo­[8.2.1.14,7.02,9.03,8]tetra­deca-5,11-diene-1,4,5,6,11,12-hexa­carboxyl­ate

    PubMed Central

    Lough, Alan J.; Jack, Kelsey; Tam, William

    2012-01-01

    In the title compound, C24H24O14, the stereochemistry at the cyclo­butane ring is cis-anti-cis and the –COOMe groups in the bicyclic rings are syn to each other. The mol­ecule lies on a twofold rotation axis. In the crystal, weak C—H⋯O hydrogen bonds connect mol­ecules into chains along [001], forming R 2 2(10) rings. PMID:23125745

  18. Addition polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and Bis-dienes. 2: Evidence for thermal dehydration occurring in the cure process

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Olshavsky, Michael A.; Meador, Michael A.; Ahn, Myong-Ku

    1988-01-01

    Diels-Alder cycloaddition copolymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and anthracene end-capped polyimide oligomers appear, by thermogravimetric analysis (TGA), to undergo dehydration at elevated temperatures. This would produce thermally stable pentiptycene units along the polymer backbone, and render the polymers incapable of unzipping through a retro-Diels-Alder pathway. High resolution solid 13C nuclear magnetic resonance (NMR) of one formulation of the polymer system before and after heating at elevated temperatures, shows this to indeed be the case. NMR spectra of solid samples of the polymer before and after heating correlated well with those of the parent pentiptycene model compound before and after acid-catalyzed dehydration. Isothermal gravimetric analyses and viscosities of the polymer before and after heat treatment support dehydration as a mechanism for the cure reaction.

  19. {2-[(η5-Cyclo­penta­dien­yl)diphenyl­meth­yl]-1H-imidazolido-κN}bis­(N,N-diethyl­amido)­titanium(IV)

    PubMed Central

    Cai, Xianfeng; Xu, Yingying; Nie, Wanli; Borzov, Maxim V.

    2011-01-01

    The chemically achiral title mol­ecule, [Ti(C4H10N)2(C21H16N2)], crystallizes in the chiral space group P21. All three N atoms coordinating to the TiIV atom adopt planar environments [sums of valence angles = 359.5 (6), 360.0 (7) and 360.0 (6)°], which is indicative of pπ–dπ donation from all of these N atoms to the metal and, thus, of the formal 18 e− nature of the complex. The overall coordination about the TiIV atom is distorted tetra­hedral, assuming the cyclo­penta­dienyl ring occupies one coordination site. The Ti—Nimidazole amide-type bond is longer by approximately 0.16 Å than the other two Ti—Namide bonds. PMID:21754286

  20. Bis(μ-2-tert-butyl-phenyl-imido-1:2κN:N)chlorido-2κCl-(diethyl ether-1κO)(2η-penta-methyl-cyclo-penta-dien-yl)lithiumtantalum(V).

    PubMed

    Cole, Jacqueline M; Chan, Michael C W; Gibson, Vernon C; Howard, Judith A K

    2011-06-01

    In the title compound, [LiTa(C(10)H(15))(C(10)H(13)N)(2)Cl(C(4)H(10)O)], the Ta(V) atom is coordinated by a η(5)-penta-methyl-cyclo-penta-dienyl (Cp*) ligand, a chloride ion and two N-bonded 2-tert-butyl-phenyl-imide dianions. With respect to the two N atoms, the chloride ion and the centroid of the Cp* ring, the tantalum coordination geometry is approximately tetra-hedral. The lithium cation is bonded to both the 2-tert-butyl-phenyl-imide dianions and also a diethyl ether mol-ecule, in an approximate trigonal planar arrangement. The Ta⋯Li separation is 2.681 (15) Å. In the crystal, a weak C-H⋯Cl inter-action links the mol-ecules. When compared to the 2,6-diisopropyl-phenyl-imide analogue ('the Wigley derivative') of the title compound, the two structures are conformationally matched with an overall r.m.s. difference of 0.461Å. PMID:21754594

  1. (3-Chloro­phen­yl){2-eth­oxy-5-[(Z)-hydroxy(phen­yl)methyl­idene]cyclo­penta-1,3-dien-1-yl}methanone

    PubMed Central

    Tinţaş, Mihaela-Liliana; Varga, Richard A.; Grosu, Ion; Bogdan, Elena

    2012-01-01

    The title compound, C21H17ClO3, which crystallizes as one of two possible oxo/hy­droxy-fulvene prototropic tautomers, possesses a strong intra­molecular O—H⋯O hydrogen bond that closes a seven-membered ring. The dihedral angles between the central five-membered ring and two pendant rings are 55.05 (9) and 44.51 (10)°. The crystal packing is characterized by weak inter­molecular C—H⋯O inter­actions between an H atom of the oxymethyl­ene unit and the carbonyl group of an adjacent mol­ecule, resulting in formation of chains of mol­ecules along the a axis. PMID:22346947

  2. (Glycol-κ2 O,O′)nitros­yl(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) bis­(tri­fluoro­methane­sulfonate)

    PubMed Central

    Munie, Semeret; Larsen, Anna; Gembicky, Milan

    2008-01-01

    The title compound, [Ru(C10H15)(NO)(HOCH2CH2OH)](CF3SO3)2, possesses a three-legged piano-stool geometry around the Ru atom, with an average Ru—O distance of 2.120 (6) Å and an Ru—N—O angle of 159.45 (14)°. The ethyl­eneglycol ligand forms a non-planar metallacyclic ring by chelating the Ru atom via the O atoms. The O⋯O distances of 2.554 (2) and 2.568 (2) Å are indicative of hydrogen bonding between coordinated ethyl­eneglycol and outer-sphere trifluoro­methane­sulfonate fragments. The crystal packing is stabilized by ionic forces and several CH3⋯·F (2.585 and 2.640 Å) and CH3⋯O inter­actions (2.391, 2.678, 2.694 and 2.699 Å) between the penta­methyl­cyclo­penta­dienyl ligand and trifluoro­methane­sulfonate anion. There is noticeable short inter­molecular contact [2.9039 (16) Å], between an O atom of the SO3 group and a C atom of the penta­methyl­cyclo­penta­dienyl ligand. PMID:21201270

  3. A purple odyssey: synthesis and structure of 3-amino-4-hy­droxy-6-oxo­cyclo­hexa-2,4-dien-1-iminium chloride monohydrate

    PubMed Central

    Plater, M. John; Harrison, William T. A.

    2016-01-01

    In the cation of the title hydrated mol­ecular salt, C6H7N2O2 +·Cl−·H2O, the six-membered ring shows unequal bond lengths consistent with delocalization of electrons over two separate 6π systems with single bonds between them. In the crystal, the components are linked by N—H⋯Cl, N—H⋯O, O—H⋯Cl and O—H⋯O hydrogen bonds, generating double layers propagating in (100). PMID:27307999

  4. 5,5,7,12,14,14-Hexamethyl-1,8-diaza-4,11-diazo­niacyclo­tetra­deca-4,11-diene dichloride trihydrate

    PubMed Central

    Ismail, Wafiuddin; Yamin, Bohari M.; Daran, Jean-Claude

    2012-01-01

    In the title compound, C16H34N4 2+·2Cl−·3H2O, the two protonated N atoms in the macrocyclic ring of the dication are located at diagonally opposite positions. There are two intramolecular N—H⋯N hydrogen bonds in the cation. The crystal structure features O—H⋯Cl, O—H⋯O, C—H⋯Cl and N—H⋯Cl hydrogen bonds. PMID:22590349

  5. Crystal structure of 1,1,2,2-tetra­methyl-1,2-bis­(2,3,4,5-tetra­methyl­cyclo­penta-2,4-dien-1-yl)disilane

    PubMed Central

    Godemann, Christian; Spannenberg, Anke; Beweries, Torsten

    2015-01-01

    The mol­ecular structure of the title compound, C22H38Si2, features a trans arrangement of the cyclo­penta­dienyl rings to avoid steric strain [C—Si—Si—C torsion angle = −179.0 (5)°]. The Si—Si bond length is 2.3444 (4) Å. The most notable inter­molecular inter­actions in the mol­ecular packing are C—H⋯π contacts that lead to the formation of wave-like supra­molecular chains along the b axis. PMID:26594581

  6. Crystal structure of 1,1,2,2-tetra-methyl-1,2-bis-(2,3,4,5-tetra-methyl-cyclo-penta-2,4-dien-1-yl)disilane.

    PubMed

    Godemann, Christian; Spannenberg, Anke; Beweries, Torsten

    2015-11-01

    The mol-ecular structure of the title compound, C22H38Si2, features a trans arrangement of the cyclo-penta-dienyl rings to avoid steric strain [C-Si-Si-C torsion angle = -179.0 (5)°]. The Si-Si bond length is 2.3444 (4) Å. The most notable inter-molecular inter-actions in the mol-ecular packing are C-H⋯π contacts that lead to the formation of wave-like supra-molecular chains along the b axis. PMID:26594581

  7. cyclo-Tri-μ-oxido-tris-{[(η,η)-1,2-bis-(cyclo-penta-dien-yl)-1,1,2,2-tetra-methyl-disilane]zirconium(IV)}: a trimeric disila-bridged oxidozirconocene.

    PubMed

    Arnold, Thomas; Braunschweig, Holger; Gruss, Katrin

    2011-04-01

    The title compound, [Zr(3)(C(14)H(20)Si(2))(3)O(3)], consists of three disila-bridged zirconocene units, which are connected via an oxide ligand, forming a nearly planar six-membered ring with a maximum displacement of 0.0191 (8) Å. The compound was isolated as a by-product from a mixture of [(C(5)H(4)SiMe(2))(2)ZrCl(2)] and Li[AlH(4)] in Et(2)O. PMID:21753927

  8. The Structure and Assembly Mechanism of a Novel Three-Stranded Tubulin Filament that Centers Phage DNA

    PubMed Central

    Zehr, Elena A.; Kraemer, James A.; Erb, Marcella L.; Coker, Joanna K.C.; Montabana, Elizabeth A.; Pogliano, Joe; Agard, David A.

    2014-01-01

    SUMMARY Tubulins are a universally conserved protein superfamily that carry out diverse biological roles by assembling filaments with very different architectures. The underlying basis of this structural diversity is poorly understood. Here, we determine a 7.1 Å cryo-EM reconstruction of the bacteriophage-encoded PhuZ filament and provide molecular-level insight into its cooperative assembly mechanism. The PhuZ family of tubulins is required to actively center the phage within infected host cells, facilitating efficient phage replication. Our reconstruction and derived model reveal the first example of a three-stranded tubulin filament. We show that the elongated C-terminal tail simultaneously stabilizes both longitudinal and lateral interactions, which in turn define filament architecture. Identified interaction surfaces are conserved within the PhuZ family, and their mutagenesis compromises polymerization in vitro and in vivo. Combining kinetic modeling of PhuZ filament assembly and structural data we suggest a common filament structure and assembly mechanism for the PhuZ family of tubulins. PMID:24631461

  9. Family health consequences of modernisation programmes in Black Thai communities.

    PubMed

    Oosterhoff, Pauline; White, Joanna; Nguyen, Thi Huong

    2011-12-01

    Southeast Asian governments implement ambitious programmes to reduce population growth and maternal mortality in areas with large minority ethnic populations. Although some of these programmes introduce new social and health practices that meet their broader aims, they may pay inadequate attention to the protective and medically beneficial aspects of traditional practices. This study examined the decline of temporary matrilocality (zu kuay) among the Black Thai in Dien Bien, Vietnam, as a response to policies adopted under the government programme of Doi Moi ('modernisation'). The patrilocal, patrilinear cultural norms of the majority ethnic Kinh people were promoted and zu kuay discouraged at a time when heroin availability increased dramatically but harm reduction programmes were not yet in place. This historical coincidence appears to have heightened certain Thai women's vulnerability to marriages with HIV-positive injecting drug users. Policies and guidelines on marriage and reproductive health should take into account the role of minority ethnic traditions, as well as local health-seeking practices, in order not only to improve reproductive programmes but also to reduce HIV vulnerability. PMID:21491273

  10. Trichinella infection in wild boars and synanthropic rats in northwest Vietnam.

    PubMed

    Thi, N Vu; Nguyen, V D; Praet, N; Claes, L; Gabriël, S; Huyen, N T; Dorny, P

    2014-02-24

    Trichinellosis is an emerging parasitic zoonosis in North Vietnam. In this survey, hunted and farm-bred wild boars as well as synanthropic rats were sampled in two provinces of northwest Vietnam where outbreaks of trichinellosis have recently occurred. Evidence of Trichinella infection was studied by parasitological, serological and molecular methods. The results showed relatively low prevalence of Trichinella spiralis in hunted wild boars (2/62 (3.2%; 95% CI: 0.8- 4.8)) and rats (23/820 (2.8%; 95% CI: 13.7-32.3)). Parasite burdens in the muscle tissues were between 0.1 and 0.03 larvae/g, and 0.1 and 7 larvae/g in wild boars and rats, respectively. Seroprevalence in farm-bred wild boars was negative. The findings of Trichinella-infected rats in 7 of the 20 districts of Dien Bien and Son La provinces suggest that the parasite is circulating in these regions. These results indicate that the local population and health centers should be made aware of the risks of eating raw or undercooked meat dishes prepared from wild animals. PMID:24360291

  11. If Your Child Learns in Two Languages: A Parent's Guide for Improving Educational Opportunities for Children Acquiring English as a Second Language = Si su nino aprende en dos idiomes: Una guia para que las familias sepan como mejorar las oportunidades educativas de los ninos que adquieren el ingles como segunda lengua = Neu lon Ban Hoc Bang Hai Thu Tieng: Chi-nam cua phu-huynh de cai tien co hoi hoc van cua con em dang hoc Anh van nhu sinh ngu thu hai.

    ERIC Educational Resources Information Center

    Zelasko, Nancy; Antunez, Beth

    This guide, in English, Spanish, and Vietnamese, aims to inform parents of students who have learned or are learning English as a Second Language about appropriate approaches for educating children so that they can work with schools to ensure a high quality education for their children. The emphasis is on explaining the laws, schools, and research…

  12. Delta. sup 2 -triterpenes: Early intermediates in the diagenesis of terrigenous triterpenoids

    SciTech Connect

    Ten Haven, H.L. ); Peakman, T.M. ); Rullkoetter, J. )

    1992-05-01

    A series of {Delta}{sup 2}-triterpenoids (oleana-2,12-diene, oleana-2,13(18)-diene, oleana-2,18-diene, ursa-2,12-diene, and tarazera-2,14-diene) has been identified in Holocene buried mangrove sediments (Florida, USA) by comparison of the mass spectra of and by co-injections with authentic standards. In the Oligocene Brandon lignite (Vermont, USA) oleana-2,12-diene and oleana-2,13(18)-diene were also identified, along with two A-ring contracted amyrin derivatives. By comparison with the sedimentary occurrence of related analogues of oxyallobetulin and betulin and the demonstrated diagenetic formation of lup-2-ene from lupan-3-one, these novel terrigenous biological markers are considered diagenetic products formed by dehydration of precursor molecules, such as {alpha}- and {beta}-amyrin, and tarazerol. The identification of these early intermediates brings us one step closer to the full understanding of the diagenetic fate of terrigenous triterpenoids.

  13. Effects of One Cycle of Recurrent Selection for Early Blight Resistance in a Diploid Hybrid Solanum phureja-S. stenotomum Population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight, caused by Alternaria solani, is the second most important foliar disease in potatoes, after late blight, around the world. Heritable early blight resistance was previously identified in a diploid hybrid population of Solanum phureja-S. stenotomum (phu-stn). Seventy-two clones, consis...

  14. Two cycles of recurrent maternal half-sib selection reduce foliar late blight in a diploid hybrid Solanum phureja-S. stenotomum population by two-thirds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum (phu-stn). The objective of this study was to determine if resistance t...

  15. Effects of Three Different Nucleoid-Associated Proteins Encoded on IncP-7 Plasmid pCAR1 on Host Pseudomonas putida KT2440

    PubMed Central

    Suzuki-Minakuchi, Chiho; Hirotani, Ryusuke; Shintani, Masaki; Takeda, Toshiharu; Takahashi, Yurika; Matsui, Kazuhiro; Vasileva, Delyana; Yun, Choong-Soo; Okada, Kazunori; Yamane, Hisakazu

    2015-01-01

    Nucleoid-associated proteins (NAPs), which fold bacterial DNA and influence gene transcription, are considered to be global transcriptional regulators of genes on both plasmids and the host chromosome. Incompatibility P-7 group plasmid pCAR1 carries genes encoding three NAPs: H-NS family protein Pmr, NdpA-like protein Pnd, and HU-like protein Phu. In this study, the effects of single or double disruption of pmr, pnd, and phu were assessed in host Pseudomonas putida KT2440. When pmr and pnd or pmr and phu were simultaneously disrupted, both the segregational stability and the structural stability of pCAR1 were markedly decreased, suggesting that Pmr, Pnd, and Phu act as plasmid-stabilizing factors in addition to their established roles in replication and partition systems. The transfer frequency of pCAR1 was significantly decreased in these double mutants. The segregational and structural instability of pCAR1 in the double mutants was recovered by complementation of pmr, whereas no recovery of transfer deficiency was observed. Comprehensive phenotype comparisons showed that the host metabolism of carbon compounds, which was reduced by pCAR1 carriage, was restored by disruption of the NAP gene(s). Transcriptome analyses of mutants indicated that transcription of genes for energy production, conversion, inorganic ion transport, and metabolism were commonly affected; however, how their products altered the phenotypes of mutants was not clear. The findings of this study indicated that Pmr, Pnd, and Phu act synergistically to affect pCAR1 replication, maintenance, and transfer, as well as to alter the host metabolic phenotype. PMID:25681185

  16. Holo- And Apo- Structures of Bacterial Periplasmic Heme Binding Proteins

    SciTech Connect

    Ho, W.W.; Li, H.; Eakanunkul, S.; Tong, Y.; Wilks, A.; Guo, M.; Poulos, T.L.

    2009-06-01

    An essential component of heme transport in Gram-negative bacterial pathogens is the periplasmic protein that shuttles heme between outer and inner membranes. We have solved the first crystal structures of two such proteins, ShuT from Shigella dysenteriae and PhuT from Pseudomonas aeruginosa. Both share a common architecture typical of Class III periplasmic binding proteins. The heme binds in a narrow cleft between the N- and C-terminal binding domains and is coordinated by a Tyr residue. A comparison of the heme-free (apo) and -bound (holo) structures indicates little change in structure other than minor alterations in the heme pocket and movement of the Tyr heme ligand from an 'in' position where it can coordinate the heme iron to an 'out' orientation where it points away from the heme pocket. The detailed architecture of the heme pocket is quite different in ShuT and PhuT. Although Arg{sup 228} in PhuT H-bonds with a heme propionate, in ShuT a peptide loop partially takes up the space occupied by Arg{sup 228}, and there is no Lys or Arg H-bonding with the heme propionates. A comparison of PhuT/ShuT with the vitamin B{sub 12}-binding protein BtuF and the hydroxamic-type siderophore-binding protein FhuD, the only two other structurally characterized Class III periplasmic binding proteins, demonstrates that PhuT/ShuT more closely resembles BtuF, which reflects the closer similarity in ligands, heme and B{sub 12}, compared with ligands for FhuD, a peptide siderophore.

  17. Tuberculome de Bouchut dans la tuberculose multi focale: à propos de quatre cas

    PubMed Central

    Janah, Hicham; Alami, Ahmed; Souhi, Hicham; Zegmout, Adil; Naji-Amrani, Hicham; Raoufi, Mohamed; Elouazzani, Hanane; Rhorfi, Ismail Abderrahmani; Abid, Ahmed

    2014-01-01

    La tuberculose multifocale a connu un regain de fréquence avec la pandémie du SIDA, elle s'observe encore chez des sujets non infectés par le VIH surtout dans les pays en voie de développement notamment au Maroc. Nous rapportons quatre observations de tuberculose multifocale chez trois patients immunocompétents et un patient immunodéprimé. Quatre patients ont bénéficié d'un bilan phtisiologique, biologique, sérologique(HIV), radiologique et d'angiographie à la fluorescéine pour suspicion de tuberculose multifocale. Il s'agit de trois hommes et une femme, d’âge moyen de 44 ans, trois patients sont immunocompétents et un patient séropositif. La tuberculose intéressait trois localisations chez les quatre patients: pulmonaire dans quatre cas, ophtalmique dans quatre cas, digestive dans un cas, urinaire dans un cas, cérébrale dans un cas et un cas d'atteinte de la moelle osseuse. L'atteinte ophtalmologique est représentée par des nodules choroïdiens de Bouchut dans quatre cas et un nodule papillaire de Bouchut dans un cas; aucun des ces patients ne présentait une uvéite granulomateuse. Nos malades ont reçu un traitement anti-tuberculeux d'une durée de neuf mois avec une bonne évolution clinique, biologique, radiologique et angiographique. Au Maroc, la tuberculose continue à surprendre aussi bien par son extension touchant le sujet débilité et le sujet immunocompétent, que par ses présentations diverses y compris l'atteinte oculaire qu'elle faut rechercher par un examen ophtalmologique soigneux et systématique. PMID:25478047

  18. Source identification and distribution reveals the potential of the geochemical Antarctic sea ice proxy IPSO25.

    PubMed

    Belt, S T; Smik, L; Brown, T A; Kim, J-H; Rowland, S J; Allen, C S; Gal, J-K; Shin, K-H; Lee, J I; Taylor, K W R

    2016-01-01

    The presence of a di-unsaturated highly branched isoprenoid (HBI) lipid biomarker (diene II) in Southern Ocean sediments has previously been proposed as a proxy measure of palaeo Antarctic sea ice. Here we show that a source of diene II is the sympagic diatom Berkeleya adeliensis Medlin. Furthermore, the propensity for B. adeliensis to flourish in platelet ice is reflected by an offshore downward gradient in diene II concentration in >100 surface sediments from Antarctic coastal and near-coastal environments. Since platelet ice formation is strongly associated with super-cooled freshwater inflow, we further hypothesize that sedimentary diene II provides a potentially sensitive proxy indicator of landfast sea ice influenced by meltwater discharge from nearby glaciers and ice shelves, and re-examination of some previous diene II downcore records supports this hypothesis. The term IPSO25-Ice Proxy for the Southern Ocean with 25 carbon atoms-is proposed as a proxy name for diene II. PMID:27573030

  19. Metal-Free Hydrosilylation Polymerization by Borane Catalyst.

    PubMed

    Kim, Dong Wook; Joung, Seewon; Kim, Jeung Gon; Chang, Sukbok

    2015-12-01

    The first example of metal-free hydrosilylation polymerization between dienes and disilanes is developed by using a borane catalyst, B(C6F5)3 to replace precious transition-metal-based systems. Under the easy-to-handle and mild conditions, a step-growth polymerization of two readily available diene and disilane units was achieved with high degrees of polymerization. Various combinations of dienes and disilanes produced polycarbosilanes with a broad range of structures and properties. PMID:26474096

  20. Diversity-Oriented Approaches to Polycyclics and Bioinspired Molecules via the Diels-Alder Strategy: Green Chemistry, Synthetic Economy, and Beyond.

    PubMed

    Kotha, Sambasivarao; Chavan, Arjun S; Goyal, Deepti

    2015-05-11

    We describe diverse approaches to various dienes and their utilization in the Diels-Alder reaction to produce a variety of polycycles. The dienes covered here are prepared by simple alkylation reaction or via the Claisen rearrangement or by enyne metathesis of alkyne or enyne building blocks. Here, we have also included the Diels-Alder chemistry of dendralenes, a higher analog of cross-conjugated dienes. The present article is inclusive of o-xylylene derivatives that are generated in situ starting with benzosultine or benzosulfone derivatives. The Diels-Alder reaction of these dienes with various dienophiles gave diverse polycyclic systems and biologically important targets. PMID:25875156

  1. Bis[1,2-bis­(meth­oxy­carbon­yl)ethene-1,2-dithiol­ato-κ2 S,S′]bis­(η5-penta­methyl­cyclo­penta­dien­yl)tetra-μ3-sulfido-tetra­iron(4 Fe–Fe) hexa­fluoridophosphate

    PubMed Central

    Inomata, Shinji; Ito, Shohei; Takase, Tsugiko

    2013-01-01

    The asymmetric unit of the title compound, [Fe4(C6H6O4S2)2(C10H15)2S4]PF6, contains two different complex cations and two PF6 − anions. The two complex cations have similar conformations with the butterfly-like Fe4S4 core surrounded by two penta­methyl­cyclo­penta­dienyl ligands and the S atoms of two dithiol­ate ligands. In each Fe4S4 core, there are four short Fe—Fe and two long Fe⋯Fe contacts, suggesting bonding and non-bonding inter­actions, respectively. The Fe—S distances range from 2.1287 (13) to 2.2706 (16) Å for one and from 2.1233 (13) to 2.2650 (16) Å for the other Fe4S4 core. The Fe—S distances involving the dithiol­ate ligands are in a more narrow range [2.1764 (16)–2.1874 (13) Å for one and 2.1743 (14)–2.1779 (16) Å for the other cation]. There are no significant inter­actions between cations and anions. PMID:23634019

  2. Tetra-tert-butyl 13,14-dioxapenta­cyclo­[8.2.1.14,7.02,9.03,8]tetra­deca-5,11-diene-5,6,11,12-tetra­carboxyl­ate

    PubMed Central

    Lough, Alan J.; Jack, Kelsey; Tam, William

    2012-01-01

    The stereochemistry of the title compound, C32H44O10, at the cyclo­butane ring is cis-anti-cis. The mol­ecule lies across an inversion center. In the crystal, weak C—H⋯O hydrogen bonds connect mol­ecules into chains along [100], forming R 2 2(6) rings. PMID:23125744

  3. Tetra­methyl 1,4-dimethyl-13,14-dioxa­penta­cyclo­[8.2.1.14,7.02,9.03,8]tetra­deca-5,11-diene-5,6,11,12-tetra­carboxyl­ate

    PubMed Central

    Lough, Alan J.; Jack, Kelsey; Tam, William

    2012-01-01

    In the title compound, C22H24O14, the relative stereochemistry at the cyclo­butane ring is cis-anti-cis and the methyl groups in the bicyclic rings are syn to each other. The two carboxyl­ate groups attached to the same —C=C— bond are disordered over two sets of sites in a 0.603 (2):0.397 (2) ratio. In the crystal, weak C—H⋯O hydrogen bonds connect mol­ecules into C(12) chains along [001] incorporating R 2 2 2(10) rings. PMID:23125743

  4. [1,1′-Bis(di­phenyl­phosphan­yl)cobalto­cenium-κ2 P,P′](η5-cyclo­penta­dien­yl){2-[4-(4-ethynylphen­yl)phen­yl]ethynyl-κC}ruthenium(II) hexa­fluorido­phosphate

    PubMed Central

    Zeng, Ling-Zhen; Wu, Yun-Ying; Tian, Guang-Xuan; Li, Zhen

    2013-01-01

    In the title compound, [CoRu(C5H5)(C16H9)(C17H14P)2]PF6, the RuII atom is coordinated by a cyclo­penta­dienyl ring in an η5-mode, one C atom from a 4,4′-diethynyl-1,1′-biphenyl ligand and two P atoms from a chelating 1,1′-bis­(di­phenyl­phosphan­yl)cobaltocenium ligand, giving a three-legged piano-stool geometry. In the crystal, weak C—H⋯F hydrogen bonds link the complex cations and hexa­fluorido­phosphate anions into a three-dimensional supra­molecular structure. PMID:24454037

  5. Trichlorido-1κ2 Cl,2κCl-(2,6-dimethyl­phenolato-2κO)-μ-oxido-bis{1,2(η5)-2,3,4,5-tetra­methyl-1-[4-(trimethyl­silyl)phen­yl]cyclo­penta­dien­yl}dititanium(IV)

    PubMed Central

    Luo, Xuyang; Wu, Qiaolin; Mu, Ying

    2011-01-01

    The title dinuclear titanocene, [Ti2(C8H9O)(C18H25Si)2Cl3O], contains one Ti atom tetra­hedrally coordinated by two Cl atoms, a bridging O atom and the substituted cyclo­penta­dienyl ligand, and another Ti atom tetra­hedrally coordinated by a Cl atom, a bridging O atom, the 2,6-dimethyl­phenolate ligand and the substituted cyclo­penta­dienyl ligand. The bridging O atom lies on a twofold rotation axis. PMID:22064795

  6. Crystal structures of (1E,4E)-1,5-bis­(5-bromo­thio­phen-2-yl)-2,4-di­methyl­penta-1,4-dien-3-one and (E)-4-(5-bromo­thio­phen-2-yl)-1,3-di­phenyl­but-3-en-2-one

    PubMed Central

    Nithya, C.; Sithambaresan, M.; Kurup, M. R. Prathapachandra

    2016-01-01

    The title compounds, C15H12Br2OS2, (I), and C20H15BrOS, (II), were synthesized by employing Claisen–Schmidt condensation of pentan-3-one and di­benzyl­acetone with 5-bromo­thio­phene-2-carbaldehyde in the presence of methano­lic KOH. Even though 1:2 products were expected in both of the reactions, 1:2 and 1:1 products were obtained as (I) and (II), respectively. In (I), the two methyl groups are trans to each other, 29.5 (7) and 28.7 (7)° away from the central carbonyl bond between them, whereas the two phenyl rings of di­benzyl­acetone subtend a dihedral angle of 53.09 (18)°. In the crystal of (I), C—H⋯O hydrogen bonds define mol­ecular chains along c. A second type of mol­ecular chain is formed along b by means of C—Br⋯π inter­actions. These two families of mol­ecular chains are stacked by π–π inter­actions, forming a three-dimensional supra­molecular architecture. In (II), similar C—H⋯O hydrogen bonds as in (I) define inversion dimers, whilst C—H⋯.π inter­actions build a staircase structure along the a axis. PMID:26958387

  7. cyclo-Tri-μ-oxido-tris­{[(η5,η5)-1,2-bis­(cyclo­penta­dien­yl)-1,1,2,2-tetra­methyl­disilane]zirconium(IV)}: a trimeric disila-bridged oxidozirconocene

    PubMed Central

    Arnold, Thomas; Braunschweig, Holger; Gruss, Katrin

    2011-01-01

    The title compound, [Zr3(C14H20Si2)3O3], consists of three disila-bridged zirconocene units, which are connected via an oxide ligand, forming a nearly planar six-membered ring with a maximum displacement of 0.0191 (8) Å. The compound was isolated as a by-product from a mixture of [(C5H4SiMe2)2ZrCl2] and Li[AlH4] in Et2O. PMID:21753927

  8. Perinatal HIV Status and Executive Function During School-Age and Adolescence: A Comparative Study of Long-Term Cognitive Capacity Among Children From a High HIV Prevalence Setting.

    PubMed

    Ezeamama, Amara E; Kizza, Florence N; Zalwango, Sarah K; Nkwata, Allan K; Zhang, Ming; Rivera, Mariana L; Sekandi, Juliet N; Kakaire, Robert; Kiwanuka, Noah; Whalen, Christopher C

    2016-04-01

    The aim of this study was to determine whether perinatal HIV infection (PHIV), HIV-exposed uninfected (PHEU) versus HIV-unexposed (PHU) status predicted long-term executive function (EF) deficit in school-aged Ugandan children.Perinatal HIV status was determined by 18 months via DNA polymerase chain reaction test and confirmed at cognitive assessment between 6 and 18 years using HIV rapid-diagnostic test. Primary outcome is child EF measured using behavior-rating inventory of executive function questionnaire across 8 subscales summed to derive the global executive composite (GEC). EF was proxy-reported by caregivers and self-reported by children 11 years or older. Descriptive analyses by perinatal HIV status included derivation of mean, standard deviations (SD), number, and percent (%) of children with EF deficits warranting clinical vigilance. Raw scores were internally standardized by age and sex adjustment. EF scores warranting clinical vigilance were defined as ≥ mean + 1.5SD. t Tests for mean score differences by perinatal HIV status and linear-regression models were implemented in SAS version 9.4 to derive HIV status-related EF deficits (β) and 95% confidence intervals (CIs).Proxy-reported and self-reported EF were assessed in 166 and 82 children, respectively. GEC deficit was highest for PHIV (mean = 121.9, SD = 29.9), intermediate for PHEU (mean = 107.5, SD = 26.8), and lowest for PHU (mean = 103.4, SD = 20.7; P-trend < 0.01). GEC deficit levels warranting clinical vigilance occurred in 9 (15.8%), 5 (9.3%) and 0 (0%) PHIV, PHEU, and PHU children, respectively (P-trend = 0.01). Nineteen percent (n = 32) children had deficits requiring clinical vigilance in ≥2 proxy-reported EF subscales. Of these, multisubscale deficits occurred in 35.1%, 13.0%, and 9.3% of PHIV, PHEU, and PHU respectively (P-trend = 0.001). Multivariable analyses find significantly higher GEC deficits for PHIV compared with PHU and PHEU

  9. Perinatal HIV Status and Executive Function During School-Age and Adolescence

    PubMed Central

    Ezeamama, Amara E.; Kizza, Florence N.; Zalwango, Sarah K.; Nkwata, Allan K.; Zhang, Ming; Rivera, Mariana L.; Sekandi, Juliet N.; Kakaire, Robert; Kiwanuka, Noah; Whalen, Christopher C.

    2016-01-01

    Abstract The aim of this study was to determine whether perinatal HIV infection (PHIV), HIV-exposed uninfected (PHEU) versus HIV-unexposed (PHU) status predicted long-term executive function (EF) deficit in school-aged Ugandan children. Perinatal HIV status was determined by 18 months via DNA polymerase chain reaction test and confirmed at cognitive assessment between 6 and 18 years using HIV rapid-diagnostic test. Primary outcome is child EF measured using behavior-rating inventory of executive function questionnaire across 8 subscales summed to derive the global executive composite (GEC). EF was proxy-reported by caregivers and self-reported by children 11 years or older. Descriptive analyses by perinatal HIV status included derivation of mean, standard deviations (SD), number, and percent (%) of children with EF deficits warranting clinical vigilance. Raw scores were internally standardized by age and sex adjustment. EF scores warranting clinical vigilance were defined as ≥ mean + 1.5∗SD. t Tests for mean score differences by perinatal HIV status and linear-regression models were implemented in SAS version 9.4 to derive HIV status-related EF deficits (β) and 95% confidence intervals (CIs). Proxy-reported and self-reported EF were assessed in 166 and 82 children, respectively. GEC deficit was highest for PHIV (mean = 121.9, SD = 29.9), intermediate for PHEU (mean = 107.5, SD = 26.8), and lowest for PHU (mean = 103.4, SD = 20.7; P-trend < 0.01). GEC deficit levels warranting clinical vigilance occurred in 9 (15.8%), 5 (9.3%) and 0 (0%) PHIV, PHEU, and PHU children, respectively (P-trend = 0.01). Nineteen percent (n = 32) children had deficits requiring clinical vigilance in ≥2 proxy-reported EF subscales. Of these, multisubscale deficits occurred in 35.1%, 13.0%, and 9.3% of PHIV, PHEU, and PHU respectively (P-trend = 0.001). Multivariable analyses find significantly higher GEC deficits for PHIV compared with PHU

  10. Within-Host Evolution of Pseudomonas aeruginosa Reveals Adaptation toward Iron Acquisition from Hemoglobin

    PubMed Central

    Marvig, Rasmus Lykke; Damkiær, Søren; Khademi, S. M. Hossein; Markussen, Trine M.; Molin, Søren

    2014-01-01

    ABSTRACT Pseudomonas aeruginosa airway infections are a major cause of mortality and morbidity of cystic fibrosis (CF) patients. In order to persist, P. aeruginosa depends on acquiring iron from its host, and multiple different iron acquisition systems may be active during infection. This includes the pyoverdine siderophore and the Pseudomonas heme utilization (phu) system. While the regulation and mechanisms of several iron-scavenging systems are well described, it is not clear whether such systems are targets for selection during adaptation of P. aeruginosa to the host environment. Here we investigated the within-host evolution of the transmissible P. aeruginosa DK2 lineage. We found positive selection for promoter mutations leading to increased expression of the phu system. By mimicking conditions of the CF airways in vitro, we experimentally demonstrate that increased expression of phuR confers a growth advantage in the presence of hemoglobin, thus suggesting that P. aeruginosa evolves toward iron acquisition from hemoglobin. To rule out that this adaptive trait is specific to the DK2 lineage, we inspected the genomes of additional P. aeruginosa lineages isolated from CF airways and found similar adaptive evolution in two distinct lineages (DK1 and PA clone C). Furthermore, in all three lineages, phuR promoter mutations coincided with the loss of pyoverdine production, suggesting that within-host adaptation toward heme utilization is triggered by the loss of pyoverdine production. Targeting heme utilization might therefore be a promising strategy for the treatment of P. aeruginosa infections in CF patients. PMID:24803516

  11. Preference of Ruthenium-Based Metathesis Catalysts toward Z- and E-Alkenes as a Guide for Selective Reactions to Alkene Stereoisomers.

    PubMed

    Lee, Jihong; Kim, Kyung Hwan; Lee, Ok Suk; Choi, Tae-Lim; Lee, Hee-Seung; Ihee, Hyotcherl; Sohn, Jeong-Hun

    2016-09-01

    As a guide for selective reactions toward either Z- or E-alkene in a metathesis reaction, the relative preference of metathesis Ru catalysts for each stereoisomer was determined by a method using time-dependent fluorescence quenching. We found that Ru-1 prefers the Z-isomer over the E-isomer, whereas Ru-2 prefers the E-isomer over the Z-isomer. The Z/E-alkene preference of the catalysts precisely predicted the Z/E isomeric selectivity in the metathesis reactions of diene substrates possessing combinations of Z/E-alkenes. For the diene substrates, the rate order of the reactions using Ru-1 was Z,Z-1,6-diene > Z,E-1,6-diene > E,E-1,6-diene, while the completely opposite order of E,E-1,6-diene > Z,E-1,6-diene > Z,Z-1,6-diene was exhibited in the case of Ru-2. PMID:27463964

  12. Terpenes from leaves of Guarea macrophylla (Meliaceae).

    PubMed

    Lago, J H; Brochini, C B; Roque, N F

    2000-12-01

    The dichloromethane extract from the leaves of Guarea macrophylla (Meliaceae) was submitted to adsorption chromatography. Guai-6-en-10beta-ol, isopimara-7,15-dien-2alpha-ol and cycloarta-23,25-dien-3-one were isolated and identified by spectroscopic data, mainly by 1H and 13C NMR analyses; eight other known terpenoids were also isolated. PMID:11190388

  13. Learning Non-Local Dependencies

    ERIC Educational Resources Information Center

    Kuhn, Gustav; Dienes, Zoltan

    2008-01-01

    This paper addresses the nature of the temporary storage buffer used in implicit or statistical learning. Kuhn and Dienes [Kuhn, G., & Dienes, Z. (2005). Implicit learning of nonlocal musical rules: implicitly learning more than chunks. "Journal of Experimental Psychology-Learning Memory and Cognition," 31(6) 1417-1432] showed that people could…

  14. Antifungal isopimaranes from Hypoestes serpens.

    PubMed

    Rasoamiaranjanahary, L; Guilet, D; Marston, A; Randimbivololona, F; Hostettmann, K

    2003-09-01

    Five isopimarane diterpenes (7beta-hydroxyisopimara-8,15-dien-14-one, 14alpha-hydroxyisopimara-7,15-dien-1-one, 1beta,14alpha-dihydroxyisopimara-7,15-diene, 7beta-hydroxyisopimara-8(14),15-dien-1-one and 7beta-acetoxyisopimara-8(14),15-dien-1-one) have been isolated from the leaves of Hypoestes serpens (Acanthaceae). All compounds exhibited antifungal activity against both the plant pathogenic fungus Cladosporium cucumerinum and the yeast Candida albicans; two of them also displayed an acetylcholinesterase inhibition. The structures of the compounds were determined by means of spectrometric methods, including 1D and 2D NMR experiments and MS analysis. PMID:12943772

  15. Triterpenes from Protium hebetatum resin.

    PubMed

    Marques, Delcio Dias; Graebner, Ilmar Bernardo; de Lemos, Telma Leda Gomes; Machado, Luciana Lucas; Assunção, Jõao Carlos Costa; Monte, Francisco José Queiroz

    2010-08-01

    Three olean (beta-amyrenone, beta-amyrin and maniladiol), three ursane (alpha-amyrinone, alpha-amyrin and breine) and four tirucallane (3-oxotirucalla-8,24-dien-21-6ic acid, 3alpha-hydroxytirucalla-8,24-dien-21-oic acid, 3alpha-acetoxytirucalla-8,24-dien-21-oic acid and 3alpha-hydroxytirucalla-7,24-dien-21-oic acid) triterpenes were isolated from the oleoresin of Protium hebetatum Daly. The structures were established mainly by 13C, 1D and 2D NMR spectroscopic analysis. The isolation of 3alpha-hydroxytirucalla-8,24-dien-21-oic acid permitted correction of the chemical shift assignments of some of its carbon atoms. PMID:20839613

  16. Biotransformation of dianabol with the filamentous fungi and β-glucuronidase inhibitory activity of resulting metabolites.

    PubMed

    Khan, Naik T; Zafar, Salman; Noreen, Shagufta; Al Majid, Abdullah M; Al Othman, Zeid A; Al-Resayes, Saud Ibrahim; Atta-ur-Rahman; Choudhary, M Iqbal

    2014-07-01

    Biotransformation of the anabolic steroid dianabol (1) by suspended-cell cultures of the filamentous fungi Cunninghamella elegans and Macrophomina phaseolina was studied. Incubation of 1 with C. elegans yielded five hydroxylated metabolites 2-6, while M. phaseolina transformed compound 1 into polar metabolites 7-11. These metabolites were identified as 6β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (2), 15α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (3), 11α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (4), 6β,12β,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (5), 6β,15α,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (6), 17β-hydroxy-17α-methylandrost-1,4-dien-3,6-dione (7), 7β,17β,-dihydroxy-17α-methylandrost-1,4-dien-3-one (8), 15β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (9), 17β-hydroxy-17α-methylandrost-1,4-dien-3,11-dione (10), and 11β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (11). Metabolite 3 was also transformed chemically into diketone 12 and oximes 13, and 14. Compounds 6 and 12-14 were identified as new derivatives of dianabol (1). The structures of all transformed products were deduced on the basis of spectral analyses. Compounds 1-14 were evaluated for β-glucuronidase enzyme inhibitory activity. Compounds 7, 13, and 14 showed a strong inhibition of β-glucuronidase enzyme, with IC50 values between 49.0 and 84.9 μM. PMID:24755238

  17. Formation of ternary complexes by coordination of (diethylenetriamine)-platinum(II) to N1 or N7 of the adenine moiety of the antiviral nucleotide analogue 9.

    PubMed

    Kampf, G; Lüth, M S; Kapinos, L E; Müller, J; Holý, A; Lippert, B; Sigel, H

    2001-05-01

    The synthesis of (Dien)Pt(PMEA-N1), where Dien = diethylenetriamine and PMEA2- = dianion of 9-[2-(phosphonomethoxy)ethyl]adenine, is described. The acidity constants of the threefold protonated H3[(Dien)Pt(PMEA-N1)]3+ complex were determined and in part estimated (UV spectrophotometry and potentiometric pH titration): The release of the proton from the (N7)H+ site in H4[(Dien)Pt(PMEA-N1)]3+ occurs with a rather low pKa (= 0.52+/-0.10). The release of the proton from the -P(O)2(OH) group (pKa = 6.69+/-0.03) in H[(Dien)Pt(PMEA-N1)]+ is only slightly affected by the N1-coordinated (Dien)Pt2+ unit. Comparison with the acidic properties of the H[(Dien)Pt(PMEA-N7)]+ species provides evidence that in the (Dien)Pt(PMEA-N7) complex in aqueous solution an intramolecular, outer-sphere macrochelate is formed through hydrogen bonds between the -PO3(2-) residue of PMEA2- and a PtII-coordinated (Dien)NH2 group; its formation degree amounts to about 40%. The stability constants of the M[(Dien)Pt(PMEA-N1)]2+ complexes with M2+ = Mg2+, Ca2+, Ni2+, Cu2+ and Zn2+ were measured by potentiometric pH titrations in aqueous solution at 25 degrees C and I = 0.1 M (NaNO3). Application of previously determined straight-line plots of log K(M(R-PO3))M versus pK(H(R-PO3)H for simple phosph(on)ate ligands. R-PO3(2-), where R represents a non-inhibiting residue without an affinity for metal ions, proves that the primary binding site of (Dien)Pt(PMEA-N1) is the phosphonate group with all metal ions studied; in fact, Mg2+, Ca2+ and Ni2+ coordinate (within the error limits) only to this site. For the Cu[(Dien)Pt(PMEA-N1)]2+ and Zn[(Dien)Pt(PMEA-N1)]2- systems also the formation of five-membered chelates involving the ether oxygen of the -CH2-O-CH2-PO3(2-) residue could be detected; the formation degrees are about 60% and 30%, respectively. The metal-ion-binding properties of the isomeric (Dien)Pt(PMEA-N7) species studied previously differ in so far that the resulting M[(Dien)Pt(PMEA-N7)]2+ complexes

  18. 12. Photocopy of map from Atlas of Westchester County by ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Photocopy of map from Atlas of Westchester County by Joseph E. Bien, published by Julius Bien & Company, New York, 1893 - Moquette Row Housing, Moquette Row North & Moquette Row South, Yonkers, Westchester County, NY

  19. A non-calcemic sulfone version of the vitamin D(3) analogue seocalcitol (EB 1089): chemical synthesis, biological evaluation and potency enhancement of the anticancer drug adriamycin.

    PubMed

    Posner, G H; Crawford, K R; Peleg, S; Welsh, J E; Romu, S; Gewirtz, D A; Gupta, M S; Dolan, P; Kensler, T W

    2001-09-01

    Novel side-chain diene sulfones 5, analogues of the natural hormone 1alpha,25-dihydroxyvitamin D(3) (calcitriol, 1), were designed to incorporate some of the therapeutically most favorable structural features of the Leo Pharmaceutical Company's drug candidate diene EB 1089 (seocalcitol, 4) and of the Hopkins' non-calcemic side-chain sulfone analogues 2 and 3. Synthesis of diene sulfones 5 features selective Swern oxidation of a primary silyl ether in the presence of a secondary silyl ether (9-->10) and Horner-Wadsworth-Emmons aldehyde addition by a 1-phosphonyl-3-sulfonyl stabilized carbanion regiospecifically at the 1-position to form E,E-diene sulfone 11. Sulfone diene analogue 5a with natural 1alpha,3beta-diol functionality, but not its diastereomer 5b with unnatural A-ring stereochemistry, is antiproliferative in vitro toward murine keratinocytes and malignant melanoma cells, as well as toward MCF-7 human breast cancer cells. Combining diene sulfone 5a with the currently used anticancer drug adriamycin (ADR) caused a noteworthy 3-fold enhancement of ADR antiproliferative potency in MCF-7 cells. Sulfone diene analogue 5a is weakly active transcriptionally in MCF-7 and ROS 17/2.8 cells, binds poorly but measurably to the vitamin D receptor (VDR), and desirably is non-calcemic in vivo at a daily dose (7 days) of 10 microg/kg of rat body weight. PMID:11553477

  20. Zircon U-Pb ages and geochemistry of granitoids in the Truong Son terrane, Vietnam: Tectonic and metallogenic implications

    NASA Astrophysics Data System (ADS)

    Shi, Mei-Feng; Lin, Fang-Cheng; Fan, Wen-Yu; Deng, Qi; Cong, Feng; Tran, My-Dung; Zhu, Hua-Ping; Wang, Hong

    2015-04-01

    Truong Son terrane, one of the most important tectonic and metallogenic terranes in Indochina block, is composed of many volcano-plutonic complexes. Reported here is geochronological and geochemical data obtained from six different volcano-plutonic complexes. The new data reveals that the granite from the Hai Van complex is 438 Ma in age, and shows collision-related geochemical characteristics; whereas another five samples from five volcano-plutonic complexes present consistent emplacement and crystallization ages ranging from 261 to 242 Ma. Dien Bien granodiorite, Phia Bioc monzogranite and Dong Trau rhyolite display typical subduction-related calc-alkaline affinity (e.g., depletion in Nb-Ta and Ti and enrichment in Rb and La), while monzogranite from Song Ma complex displays collision-related shoshoniteseries and granites from Bengiang-Queson complex are related to post-collision calc-alkaline series. Based on these observations, in combination with the previous published geochronological data, we propose that at least four major stages of magmatic activities occurred during the Paleozoic and the Early Mesozoic through the Truong Son terrane: Ordovician-Silurian (420-470 Ma), Late Carboniferous-Early Permian (280-300 Ma), Late Permian to Mid-Triassic (245-270 Ma) and Middle-Late Triassic (200-245 Ma). These magmatic activities are not only attributed to the Tethyan Song Ma ocean southwestward subduction but also related to Paleo Tamky-Phuoc Son oceanic bidirectional subduction. Synthesized with regional metallogenic data, we identified three metallogenic epochs: (1) Late Carboniferous-Early Permian (280-300 Ma) arc-magmatic hydrothermal Cu-Au-Fe polymetallic metallogenic system related to the Tamky-Phuoc Son ocean north-dipping subduction; (2) Late Permian-Middle Triassic (245-280 Ma) arc-magmatic hydrothermal Cu-Au-Fe and orogenic W-Sn-Au polymetallic metallogenic system, which linked to both Paleo-Tethyan Song Ma ocean south-dipping subduction and Tamky

  1. Analyse des facteurs prédictifs de malignité des goitres nodulaires : à propos de 500 cas

    PubMed Central

    Bouaity, Brahim; Darouassi, Youssef; Chihani, Mehdi; Touati, Mohamed Mliha; Ammar, Haddou

    2016-01-01

    Les nodules thyroïdiens sont très fréquents et moins de 10% d'entre eux sont malin. Ils posent un véritable problème diagnostique et thérapeutique surtout par rapport à leur nature bénigne ou maligne. L’étude de certains facteurs cliniques et paracliniques de présomption de malignité permet de bien codifier la stratégie thérapeutique. Le but de ce travail est d’étudier les facteurs prédictifs de malignité des goitres nodulaires et comparer nos résultats à ceux de la littérature. Il s'agit d'une étude rétrospective à propos de 500 cas de goitres nodulaires opérés au service d'Oto-rhino-laryngologie (ORL) et Chirurgie cervico-faciale (CCF) de l'hôpital militaire Avicenne de Marrakech entre 2006 et 2012. Le pourcentage de cancers a été de 6,8%. L’âge moyen de nos patients était de 46 ans, avec une sex-ratio de 5 (F/H). A la palpation cervicale; le caractère dure du nodule a été constaté dans 94,4% des cas de cancer, avec des limites irrégulières dans 64,70% des cas de cancer. Trois nodules étaient fixes et ils étaient tous malins. Les adénopathies cervicales ont été constatées chez 8 malades dont 7 présentaient des cancers. A l’échographie, 61,8% des nodules malins présentaient un aspect hypoéchogène, avec des contours flous dans 88,24% des cas. La vascularisation intra nodulaire était présente dans 35,3% de ces cas des cancers avec des microcalcifications chez 55,9% d'entre eux. Le halo hypoéchogene périnodulaire était incomplet dans 73,5% des cas de cancer. Nos patients étaient en euthyroïdie dans 84,6% des cas. Les facteurs prédictifs de malignité d'un goitre nodulaire, étaient donc dans notre étude d'abord cliniques: l’âge supérieur à 60 ans, la consistance dure du nodule, sa fixité, son caractère irrégulier et mal limité à la palpation, ainsi que la présence d'adénopathie(s) cervicale(s) à l'examen; et échographiques: le caractère hypoéchogène, les limites floues, la présence de

  2. Kinetics and mechanism of the oxidation of alkenes and silanes by hydrogen peroxide catalyzed by methylrhenium trioxide (MTO) and a novel application of electrospray mass spectrometry to study the hydrolysis of MTO

    SciTech Connect

    Tan, Haisong

    1999-11-08

    Conjugated dienes were oxidized by hydrogen peroxide with methylrhenium trioxide (MTO) as catalyst. Methylrhenium bis-peroxide was the major reactive catalyst present. Hydroxyalkenes and trisubstituted silane were also tested. Mechanisms for each of these reactions are presented.

  3. Ozonolysis of unsaturated compounds in the synthesis of insect pheromones and juvenoids

    NASA Astrophysics Data System (ADS)

    Ishmuratov, Gumer Yu; Kharisov, Rinat Ya; Odinokov, Viktor N.; Tolstikov, Genrikh A.

    1995-06-01

    The review surveys data on the use of the ozonolysis of cyclic and acyclic monoenes, dienes, and trienes in various stages of the total synthesis of insect pheromones and juvenoids. The bibliography includes 178 references.

  4. LINERS FOR SANITARY LANDFILLS AND CHEMICAL AND HAZARDOUS WASTE DISPOSAL SITES

    EPA Science Inventory

    This report lists addresses of sanitary landfills and chemical and hazardous waste disposal sites and holding ponds with some form of impermeable lining. Liners included are polyethylene, polyvinyl chloride, Hypalon R, ethylene propylene diene monomer, butyl rubber, conventional ...

  5. DEVELOPMENT OF CHEMICAL COMPATIBILITY CRITERIA FOR ASSESSING FLEXIBLE MEMBRANE LINERS

    EPA Science Inventory

    Laboratory testing was conducted to develop chemical resistance data using immersion tests. Six FML materials (polyvinylchloride, chlorinated polyethylene, chlorosulfonated polyethylene, high density polyethylene, epichlorohydrin and ethylene propylene diene terpolymer) were test...

  6. Pregnane-10,2-carbolactones from a Hawaiian Marine Sponge in the Genus Myrmekioderma.

    PubMed

    Dai, Jingqiu; Yoshida, Wesley Y; Kelly, Michelle; Williams, Philip

    2016-05-27

    Four new pregnanes, 3β,4β-dihydroxy-17-methyl-17α-pregna-5,13-diene-10,2-carbolactone (1), 6β-chloro-3β-hydroxy-17-methyl-17α-pregna-4,13-diene-10,2-carbolactone (2), 3β-hydroxy-6β-methoxy-17-methyl-17α-pregna-4,13-diene-10,2-carbolactone (3), and 3β,6β-dihydroxy-17-methyl-17α-pregna-4,13-diene-10,2-carbolactone (4), were isolated from an undescribed species of Myrmekioderma Ehlers along with the known pregnane carbolactone (5). The structures of the new compounds were determined by spectroscopic methods and comparison with previously described compounds. Compound 5 showed almost 4-fold activation of pregnane X receptor, while 2 inhibited BACE1 with an IC50 value of 82 μM. PMID:27104967

  7. Click and Patterned Functionalization of Graphene by Diels-Alder Reaction.

    PubMed

    Li, Jing; Li, Meng; Zhou, Li-Li; Lang, Shuang-Yan; Lu, Hai-Yan; Wang, Dong; Chen, Chuan-Feng; Wan, Li-Jun

    2016-06-22

    Chemical functionalization is a promising approach to controllably manipulate the characteristics of graphene. Here, we designed cis-dienes, featuring two dihydronaphthalene backbones, to decorate a graphene surface via Diels-Alder (DA) click reaction. The installation of a diene moiety into a nonplanar molecular structure to form cis-conformation enables a rapid (∼5 min) DA reaction between graphene and diene groups. Patterned graphene of sub-micrometer resolution can be obtained by easily soaking poly(methyl methacrylate)-masked graphene in solution of hydroxyl-substituted cis-diene at room temperature. The functionalization degree can be further controlled by carrying out the reaction at higher temperature. The present result gives important insight into the effect of molecular conformation on the graphene functionalization process, and provides an effective and facile method for graphene functionalization. PMID:27264112

  8. Thermoplastic vulcanizates: new materials of choice.

    PubMed

    Severyns, K

    2000-03-01

    Increasingly, thermoplastic vulcanizates of ethylene propylene diene monomer rubber-polypropylene are being specified for medical applications. This article describes their properties and advantages over thermoset rubbers and other conventional medical elastomeric materials. PMID:10915490

  9. Alkanediyl and related derivatives of permethylhafnocene

    SciTech Connect

    Bercaw, J.E.; Moss, J.R.

    1992-02-01

    The objective of this study was to investigate the synthesis of alkanediyl complexes of some early transition metals and to compare their chemistry with that of the known mononuclear alkyl complexes. Reactions of hafnium complexes with dienes are described.

  10. Synthesis of tetrasubstituted 1-silyloxy-3-aminobutadienes and chemistry beyond Diels–Alder reactions

    PubMed Central

    Li, Xijian; Peng, Siyu; Li, Li; Huang, Yong

    2015-01-01

    Electron-rich dienes have revolutionized the synthesis of complex compounds since the discovery of the legendary Diels–Alder cycloaddition reaction. This highly efficient bond-forming process has served as a fundamental strategy to assemble many structurally formidable molecules. Amino silyloxy butadienes are arguably the most reactive diene species that are isolable and bottleable. Since the pioneering discovery by Rawal, 1-amino-3-silyloxybutadienes have been found to undergo cycloaddition reactions with unparalleled mildness, leading to significant advances in both asymmetric catalysis and total synthesis of biologically active natural products. In sharp contrast, this class of highly electron-rich conjugated olefins has not been studied in non-cycloaddition reactions. Here we report a simple synthesis of tetrasubstituted 1-silyloxy-3-aminobutadienes, a complementarily substituted Rawal's diene. This family of molecules is found to undergo a series of intriguing chemical transformations orthogonal to cycloaddition reactions. Structurally diverse polysubstituted ring architectures are established in one step from these dienes. PMID:25898310

  11. ENSO and anthropogenic impacts on phytoplankton diversity in tropical coastal waters

    NASA Astrophysics Data System (ADS)

    Doan-Nhu, Hai; Nguyen-Ngoc, Lam; Nguyen, Chi-Thoi

    2016-01-01

    16-year phytoplankton data were analysed to assess ENSO and anthropogenic impacts on biodiversity and community structure at 3 locations (Nha-Trang and Phan-Thiet Bays and near Phu-Qui Island) in South Centre Viet Nam to understand (1) the primary scales of change in phytoplankton community structure, and traditional and taxonomic diversity indices; (2) the significance of environmental changes and/or climate variability on phytoplankton diversity; and (3) the usefulness of these long-term data for analysing future impacts of anthropogenic and climate changes. Traditional and taxonomic diversity indices were compared and tested in linkage with environmental conditions and ENSO. Nutrient data indicated stronger environmental impacts in Phan-Thiet Bay, milder in Nha-Trang Bay and less noticeable near Phu-Qui Island. There were measurable impacts of both anthropogenic and ENSO on phytoplankton at different locations in various parameters, e.g. species number, diversity and community structures. The lowest diversity was recorded in the most anthropogenically impacted site, Phan-Thiet Bay. Although a stronger impact on phytoplankton was recorded in ENSO year in Phan Thiet Bay, quantitative separation between anthropogenic and ENSO impacts using phytoplankton biodiversity indices was impossible. In the waters with less anthropogenic impacts, ENSO effects on taxonomic diversity was better indicated by negative phytoplankton responses to the ONI index (Nha-Trang Bay) and recovery of phytoplankton after the ENSO events (near Phu-Qui Island). Among the diversity indices, the taxonomic diversity indices (e.g. Δ+ and Λ+) better described impacts of ENSO than the traditional ones.

  12. Thermal rearrangements in 1,2-poly/1,4-hexadiene/s

    NASA Technical Reports Server (NTRS)

    Golub, M. A.

    1978-01-01

    The work described was carried out to study the thermal rearrangements of two unsaturated diene polymers - 1,2-poly(cis-1,4-hexadiene) (CHD) and 1,2-poly(trans-1.4-hexadiene) (THD). It is shown that both CHD and THD have a predominatly 1,8 diene structure and seem to cyclize mainly by the (2 + 2) thermal cycloaddition of double bonds, and to a small extent also by sigmatropic rearrangement with hydrogen shift.

  13. Inhibition of T-lymphocyte proliferation by cucurbitacins from Picrorhiza scrophulariaeflora.

    PubMed

    Smit, H F; van den Berg, A J; Kroes, B H; Beukelman, C J; Quarles van Ufford, H C; van Dijk, H; Labadie, R P

    2000-09-01

    Two cucurbitacin aglycons were isolated from the dried rhizomes of Picrorhiza scrophulariaeflora and were identified as 25-acetoxy-2,3, 16,20-tetrahydroxy-9-methyl-19-norlanosta-5,23-dien-22-one (picracin, 1) and 2,3,16,20,25-pentahydroxy-9-methyl-19-norlanosta-5, 23-dien-22-one (deacetylpicracin, 2). Both compounds inhibit mitogen-induced T-lymphocyte proliferation at an IC(50) value of 1 microM. PMID:11000045

  14. Three new oxazoline alkaloids from Gymnotheca chinensis.

    PubMed

    Xiao, Shi-Ji; Guo, Da-Le; Zhang, Mao-Sheng; Chen, Fang; Ding, Li-Sheng; Zhou, Yan

    2016-08-01

    Three novel oxazoline alkaloids, 1-oxa-3-azaspiro [4.5] dec-2-ene-8-one (1), 1-oxa-3-azaspiro [4.5] dec-2, 6-diene-8-one (2), and 1-oxa-3-azaspiro [4.5] dec-10-methoxy-2, 6-diene-8-one (3) were isolated from the methanol extract of the whole plant of Gymnotheca chinensis. The chemical structures were established by means of spectroscopic analysis including one- and two-dimensional NMR spectroscopy. PMID:26949983

  15. Cytotoxic sterols from the formosan brown alga Turbinaria ornata.

    PubMed

    Sheu, J H; Wang, G H; Sung, P J; Chiu, Y H; Duh, C Y

    1997-12-01

    Two hydroperoxysterols 24-hydroperoxy-24-vinyl-cholesterol (1) and 29-hydroperoxystigmasta-5,24(28)-dien-3beta-ol (2), and fucosterol (3) were isolated from the brown alga Turbinaria ornata (Sargassaceae). Hydroperoxide 2 is a new natural compound and was converted into 29-hydroxystigmasta-5,24 (28)-dien-3beta-ol (4) by reaction with LAH. Sterols 1, 2, and 4 exhibited cytotoxicity against various cancer cell lines. PMID:17252381

  16. Hand-held lactate analyzer as a tool for the real-time measurement of physical fatigue before slaughter and pork quality prediction.

    PubMed

    Rocha, L M; Dionne, A; Saucier, L; Nannoni, E; Faucitano, L

    2015-04-01

    The objectives of this study were to assess the relationship between blood lactate variation measured at the plant, and pork quality variation on a large sample size and under commercial preslaughter handling conditions. A total of 600 pigs were randomly chosen on arrival at a commercial slaughter plant and blood samples taken from the ear vein at unloading (UN), after lairage (LA), in the restrainer (RE; before stunning) and at exsanguination (EX) were analysed for lactate content using a Lactate Scout Analyzer (LSA). In order to have a large range of measures, pigs were distributed into two groups; one kept in lairage overnight (G1) and the other for 2 to 3 h (G2) before slaughter. Meat quality was assessed in the Longissimus thoracis (LT), Semimembranosus (SM) and Adductor (AD) muscles by measuring the pH 30 min postmortem (pH1) and at 24 h postmortem (pHu), the colour and the drip loss. Blood lactate levels did not differ between G1 and G2 (P>0.05). A reduced muscle lactate and glucose contents (P=0.02 and P=0.004, respectively) resulting in a lower (P<0.001) glycolytic potential (GP) was observed in the LT muscle of G1 pigs when compared with G2 loins. In the LT muscle of G1 pigs, the lower GP resulted in an increased pHu (r=-0.67; P<0.001), decreased drip loss (r=0.57; P<0.001) and darker colour (r=0.50; P<0.001) compared with G2. In both G1 and G2 pigs, the lower GP was correlated to higher pHu value in the SM and AD muscles (r=-0.73; P<0.001). The greatest correlation was observed in G2 between blood lactate levels at LA and pHu value of the SM and AD muscles (r=0.46 and r=0.44, respectively; P<0.001 for both muscles). The second greatest correlation was found between blood lactate levels at EX and pH1 value in the SM muscle in both groups (r=-0.37 and r=-0.41, respectively; P<0.001 for both groups). Based on the results of this study, it appears that blood lactate levels, as measured by the LSA, reliably reflect the physiological response of pigs to

  17. The dinosaurs of Thailand

    NASA Astrophysics Data System (ADS)

    Buffetaut, Eric; Suteethorn, Varavudh

    After more than ten years of Thai-French research, the Thai dinosaur record, from the continental rocks of the Khorat Plateau, is, to date, the best in Southeast Asia. The oldest evidence consists of footprints of small dinosaurs from the Middle to Late Jurassic Phra Wihan Formation. The most varied dinosaur assemblage hitherto found in Thailand comes from the Late Jurassic Sao Khua Formation; it is dominated by sauropods, but also includes various theropods. Large theropod footprints are known from the Early Cretaceous Phu Phan Formation. Theropods and the primitive ceratopsian Psittacosaurus occur in the Aptian-Albian Khok Kruat Formation.

  18. Within-host evolution of Pseudomonas aeruginosa reveals adaptation toward iron acquisition from hemoglobin.

    PubMed

    Marvig, Rasmus Lykke; Damkiær, Søren; Khademi, S M Hossein; Markussen, Trine M; Molin, Søren; Jelsbak, Lars

    2014-01-01

    ABSTRACT Pseudomonas aeruginosa airway infections are a major cause of mortality and morbidity of cystic fibrosis (CF) patients. In order to persist, P. aeruginosa depends on acquiring iron from its host, and multiple different iron acquisition systems may be active during infection. This includes the pyoverdine siderophore and the Pseudomonas heme utilization (phu) system. While the regulation and mechanisms of several iron-scavenging systems are well described, it is not clear whether such systems are targets for selection during adaptation of P. aeruginosa to the host environment. Here we investigated the within-host evolution of the transmissible P. aeruginosa DK2 lineage. We found positive selection for promoter mutations leading to increased expression of the phu system. By mimicking conditions of the CF airways in vitro, we experimentally demonstrate that increased expression of phuR confers a growth advantage in the presence of hemoglobin, thus suggesting that P. aeruginosa evolves toward iron acquisition from hemoglobin. To rule out that this adaptive trait is specific to the DK2 lineage, we inspected the genomes of additional P. aeruginosa lineages isolated from CF airways and found similar adaptive evolution in two distinct lineages (DK1 and PA clone C). Furthermore, in all three lineages, phuR promoter mutations coincided with the loss of pyoverdine production, suggesting that within-host adaptation toward heme utilization is triggered by the loss of pyoverdine production. Targeting heme utilization might therefore be a promising strategy for the treatment of P. aeruginosa infections in CF patients. IMPORTANCE Most bacterial pathogens depend on scavenging iron within their hosts, which makes the battle for iron between pathogens and hosts a hallmark of infection. Accordingly, the ability of the opportunistic pathogen Pseudomonas aeruginosa to cause chronic infections in cystic fibrosis (CF) patients also depends on iron-scavenging systems. While

  19. Constituents of south Indian vetiver oils.

    PubMed

    Mallavarapu, Gopal Rao; Syamasundar, Kodakandla V; Ramesh, S; Rao, Bhaskaruni R Rajeswara

    2012-02-01

    The essential oils isolated from vetiver [Vetiveria zizanioides (L.) Nash.] roots collected from four locations in south India were analyzed by GC-FID and GC-MS. Eighty constituents, representing 94.5-97.8% of the oils, have been identified. The oils from Bangalore, Hyderabad, Kundapur, and Mettupalayam were rich in sesquiterpenes and oxygenated sesquiterpenes with cedrane, bisabolane, eudesmane, eremophilane, and zizaane skeletons. The main components of the four essential oils were: eudesma-4,6-diene (delta-selinene) + beta-vetispirene (3.9-6.1%), beta-vetivenene (0.9-9.4%), 13-nor-trans-eudesma-4(15),7-dien-11-one + amorph-4-en-10-ol (5.0-6.4%), trans-eudesma-4(15),7-dien-12-ol (vetiselinenol) + (E)-opposita-4(15),7(11)-dien-12-ol (3.7-5.9%), eremophila-1 (10),11-dien-2alpha-ol (nootkatol) + ziza-6(13)-en-12-ol (khusimol) (16.1-19.2%), and eremophila-1(10),7(11)-dien-2alpha-ol (isonootkatol) + (E)-eremophila-1(10),7(11)-12-ol (isovalencenol) (5.6-6.9%). The important compounds that impart the characteristic vetiver odor are: khusimene, delta-selinene, beta-vetivenene, cyclocopacamphan-12-ol (epimers A and B), vetiselinenol, khusimol, isovalencenol, khusimone, alpha-vetivone, and beta-vetivone. The chemical profiles of the oils are comparable to Haitian vetiver oil. PMID:22474964

  20. Predicting pork quality using Vis/NIR spectroscopy.

    PubMed

    Balage, Juliana Monteiro; da Luz E Silva, Saulo; Gomide, Catarina Abdalla; Bonin, Marina de Nadai; Figueira, Ana Cristina

    2015-10-01

    Visible and near-infrared reflectance spectroscopy (Vis/NIRS) was used to predict the ultimate pH (pHu), color, intramuscular fat (IMF) and shear force (WBSF) of pork samples and to build classifiers capable of categorizing the samples by tenderness (tender or tough) and juiciness (juicy and dry). Spectra were collected from 400 to 1495nm, and 200 data points were generated for every sample (n=134). Sixty-seven percent of the sample set was used for calibration, and 33% was used for validation. Partial least squares (PLS) calibration models were developed for each characteristic measured. A coefficient of determination (R(2)) and residual prediction deviation (RPD) were used to evaluate the accuracy of the calibration models. The pHu and color prediction models developed in this study fit this classification, indicating that these predictive models can be used to predict quality traits of intact pork samples. The Vis/NIRS offered great potential for correctly classifying pork Longissimus into two tenderness and two juiciness classes. PMID:26021598

  1. Cloning and characterization of hydrogen uptake genes from Rhizobium leguminosarum.

    PubMed Central

    Leyva, A; Palacios, J M; Mozo, T; Ruiz-Argüeso, T

    1987-01-01

    A gene library of genomic DNA from the hydrogen uptake (Hup)-positive strain 128C53 of Rhizobium leguminosarum was constructed by using the broad-host-range mobilizable cosmid vector pLAFR1. The resulting recombinant cosmids contained insert DNA averaging 21 kilobase pairs (kb) in length. Two clones from the above gene library were identified by colony hybridization with DNA sequences from plasmid pHU1 containing hup genes of Bradyhizobium japonicum. The corresponding recombinant cosmids, pAL618 and pAL704, were isolated, and a region of about 28 kb containing the sequences homologous to B. japonicum hup-specific DNA was physically mapped. Further hybridization analysis with three fragments from pHU1 (5.9-kb HindIII, 2.9-kb EcoRI, and 5.0-kb EcoRI) showed that the overall arrangement of the R. leguminosarum hup-specific region closely parallels that of B. japonicum. The presence of functional hup genes within the isolated cosmid DNA was demonstrated by site-directed Tn5 mutagenesis of the 128C53 genome and analysis of the Hup phenotype of the Tn5 insertion strains in symbiosis with peas. Transposon Tn5 insertions at six different sites spanning 11 kb of pAL618 completely suppressed the hydrogenase activity of the pea bacteroids. Images PMID:2822654

  2. [Community vegetable gardens as a health promotion activity: an experience in Primary Healthcare Units].

    PubMed

    Costa, Christiane Gasparini Araújo; Garcia, Mariana Tarricone; Ribeiro, Silvana Maria; Salandini, Marcia Fernanda de Sousa; Bógus, Cláudia Maria

    2015-10-01

    Urban and peri-urban agriculture (UPA) is being practiced in different settings, contributing to the improvement of health in communities and healthier environments. In order to identify the meanings and implications of the practice of UPA in Primary Healthcare Units (PHU) as an activity of health promotion (HP), and to what extent its therapeutic dimension characterizes it as an activity aligned with complementary and integrative practices (CIP), a qualitative cross-sectional study was performed in Embu das Artes, State of São Paulo. From the analysis, the following main themes arose: health concept, health outcomes, the return to traditional practices and habits and the reorientation of health services. It was possible to identify the close link between the cultivation of vegetable gardens and HP guidelines and fields of action, such as creating healthier environments, boosting community actions, developing personal skills, stimulating autonomy and empowerment and demands for the reorientation of services. The garden activities, set up in PHU areas, proved to be an implementation strategy of CIP. The conclusion reached is that vegetable gardening activities in community gardens are seen to be health promotion practices that integrate key elements of CIP. PMID:26465852

  3. Variation in haem pigment concentration and colour in meat from British pigs.

    PubMed

    Warriss, P D; Brown, S N; Adams, S J; Lowe, D B

    1990-01-01

    Variation in chemically determined total haem pigment concentration and instrumentally determined colour was examined in 223 samples of M. longissimus dorsi (LD) representative of the majority of slaughter pigs currently produced in the UK. Whether pigs were sired by White (Large White or Landrace) or Meat-line boars did not affect any measured characteristic but source breeding company influenced total haem pigment concentration (P < 0·01). Haem pigment concentration was higher in muscles from gilts, compared with castrates, boars being intermediate. Gilts also had darker muscles, based on EEL Reflectance values (P < 0·05), and lower hue values (P < 0·05). When compared with animals fed ad-libitum, restricted-fed pigs had higher concentrations of muscle haem pigment (P < 0·001) and this resulted in meat that was slightly darker (P < 0·05), despite having lower ultimate pH (pHu) (P < 0·05), and had a lower hue value (P < 0·001). Measurements of reflectance, total soluble protein and pHu indicated that differences in the incidence of potentially pale, soft, exudative or dark, firm, dry muscle were unlikely to be important contributors to variation in the colour of the meat in this study. PMID:22055663

  4. Water displacement by cyanogold complexes in binuclear nickel(II) compounds based on bridging oxalate. Synthesis, structural diversity, magnetic properties, and DFT calculations.

    PubMed

    Vitoria, Pablo; Muga, Iñaki; Gutiérrez-Zorrilla, Juan M; Luque, Antonio; Román, Pascual; Lezama, Luis; Zúniga, F Javier; Beitia, Javier I

    2003-02-24

    Several cyanogold complexes react with the binuclear nickel complex [(Ni(dien)(H(2)O))(2)(mu-ox)](PF(6))(2).2H(2)O to give the compounds [(Ni(dien)(H(2)O))(2)(mu-ox)]Br(2) (1), [(Ni(dien)(Au(CN)(2)))(2)(mu-ox)] (2), and [(Ni(dien))(2)(mu-ox)(mu-Au(CN)(4))](PF(6)) (3) (dien, diethilenetriamine; ox, oxalate). In the case of compounds 2 and 3, water displacement by the corresponding cyanogold complex takes place, whereas compound 1 is formed by a substitution of the anion. The crystal structures of compounds 1 and 2 present a 2D arrangement where the layers are connected by van der Waals forces (1) or N-H.Ntbd1;C hydrogen bonds (2), where each binuclear complex is hydrogen bonded to its neighbors, whereas compound 3 presents a novel structure where the tetracyanoaurate acts as a bridging ligand to give a polymeric compound. Magnetic studies of these compounds reveal an antiferromagnetic behavior. Finally, density functional theory (DFT) calculations have been performed on isolated models of compounds 2 and 3 in order to gain some insight about the different behavior of the [Au(CN)(2)](-) and [Au(CN)(4)](-) groups as ligands and proton acceptors in hydrogen bonds. PMID:12588126

  5. Synthesis of novel polyfluorinated acrylic monomers and oligomers

    SciTech Connect

    Antonucci, J.M.; Stansbury, J.W.

    1993-12-31

    An unhindered tertiary amine catalyzed reaction of monofunctional and difunctional hydrocarbon acrylates with paraformaldehyde under neat conditions yields unique difunctional acrylic monomers and oligomers, respectively. These multifunctional vinyl products have a predominantly 1,6-diene structure which favors cyclopolymerization. This reaction has been extended to the synthesis of similar polyfluorinated aliphatic monomers arrangements are determined by the nature of their fluoroester groups, e.g.-CF{sub 2}CH{sub 2}O{sub 2}C- favors a 1,4-diene rather than a 1,6-diene structure. In the present study the scope of this novel formaldehyde/acrylate insertion condensation reaction was further extended to include the synthesis of polyfluorinated aryl difunctional monomers and oligomers, e.g. from 2,3,4,5,6-pentafluorobenzyl acrylate and hexafluorobisphenol A diacrylate. The former did not require DMSO and yielded 1,6-, 1,8- and 1,10-dienes whereas the latter required DMSO and yielded oligomers mainly with 1,4-diene linkages.

  6. Eupha-7,9(11),24-trien-3beta-ol ("antiquol C") and other triterpenes from Euphorbia antiquorum latex and their inhibitory effects on Epstein-Barr virus activation.

    PubMed

    Akihisa, Toshihiro; Kithsiri Wijeratne, E M; Tokuda, Harukuni; Enjo, Fumio; Toriumi, Masakazu; Kimura, Yumiko; Koike, Kazuo; Nikaido, Tamotsu; Tezuka, Yasuhiro; Nishino, Hoyoku

    2002-02-01

    The structures of three triterpene alcohols isolated from the latex of Euphorbia antiquorum were established to be eupha-7,9(11),24-trien-3beta-ol (2; antiquol C), 19(10-->9)abeo-8alpha,9beta,10alpha-eupha-5,24-dien-3beta-ol (3; antiquol B), and 24-methyltirucalla-8,24(24(1))-dien-3beta-ol (4; euphorbol) on the basis of spectroscopic methods. Compounds 3 and 4 have previously been assigned the erroneous structures of 10alpha-cucurbita-5,24-dien-3alpha-ol and 24-methyleupha-8,24(24(1))-dien-3beta-ol, respectively. Compounds 2-4 and four other known compounds isolated from the latex, euphol (1), lemmaphylla-7,21-dien-3beta-ol (5), isohelianol (6), and camelliol C (7), showed potent inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). PMID:11858748

  7. New α-Glucosidase Inhibitory Triterpenic Acid from Marine Macro Green Alga Codium dwarkense Boergs

    PubMed Central

    Ali, Liaqat; Khan, Abdul Latif; Al-Kharusi, Lubna; Hussain, Javid; Al-Harrasi, Ahmed

    2015-01-01

    The marine ecosystem has been a key resource for secondary metabolites with promising biological roles. In the current study, bioassay-guided phytochemical investigations were carried out to assess the presence of enzyme inhibitory chemical constituents from the methanolic extract of marine green alga—Codium dwarkense. The bioactive fractions were further subjected to chromatographic separations, which resulted in the isolation of a new triterpenic acid; dwarkenoic acid (1) and the known sterols; androst-5-en-3β-ol (2), stigmasta-5,25-dien-3β,7α-diol (3), ergosta-5,25-dien-3β-ol (4), 7-hydroxystigmasta-4,25-dien-3-one-7-O-β-d-fucopyranoside (5), 7-hydroxystigmasta-4,25-dien-3-one (6), and stigmasta-5,25-dien-3β-ol (7). The structure elucidation of the new compound was carried out by combined mass spectrometry and 1D (1H and 13C) and 2D (HSQC, HMBC, COSY, and NOESY) NMR spectroscopic data. The sub-fractions and pure constituents were assayed for enzymatic inhibition of alpha-glucosidase. Compound 1 showed significant inhibition at all concentrations. Compounds 2, 3, 5, and 7 exhibited a dose-dependent response, whereas compounds 4–6 showed moderate inhibition. Utilizing such marine-derived biological resources could lead to drug discoveries related to anti-diabetics. PMID:26184240

  8. Cluster synthesis. 39. New platinum-ruthenium carbonyl cluster complexes with bridging hydride ligands. Synthesis and structural characterizations of Ru sub 4 Pt(CO) sub 13 (COD)(. mu. -H) sub 2 , Ru sub 3 Pt(CO) sub 9 (. mu. -CO)(COD)(. mu. -H) sub 2 , Ru sub 4 Pt sub 2 (CO) sub 11 (COD) sub 2 (. mu. sub 3 -H) sub 2 , and Ru sub 5 Pt sub 5 (CO) sub 18 (COD) sub 2 (. mu. -H) sub 2 , COD = Cycloocta-1,5-diene

    SciTech Connect

    Adams, R.D.; Zhaoyang Li; Jauching Lii; Wengan Wu )

    1992-08-05

    The reaction of Ru{sub 4}(CO){sub 13}({mu}-H){sub 2} (1) with Pt(COD){sub 2} at 25 C yielded four new platinum-ruthenium carbonyl cluster complexes Ru{sub 4}Pt(CO){sub 13}(COD)({mu}-H){sub 2} (2) (37%), Ru{sub 3}Pt(CO){sub 9}({mu}-CO)(COD)({mu}-H){sub 2} (3) (10%), Ru{sub 4}Pt{sub 2}-(CO){sub 11}(COD){sub 2}({mu}{sub 3}-H){sub 2} (4) (2.5%), and Ru{sub 5}Pt{sub 5}(CO){sub 18}(COD){sub 2}({mu}{sub 3}-H){sub 2} (5) (1%). All compounds were characterized by IR, {sup 1}H NMR, and single-crystal X-ray diffraction analyses. The cluster of compound 2 consists of a butterfly tetrahedron of four ruthenium atoms with one triangular face capped by a Pt(COD) grouping. Compound 3 consists of a cluster of three ruthenium atoms and one platinum atom in a tetrahedral arrangement. Compound 4 consists of a tetrahedral cluster of four ruthenium atoms with two of the triangular faces capped by Pt(COD) groupings. The other two triangular faces have triply bridging hydride ligands. In the cluster of compound 5, the five ruthenium and four of the platinum atoms are arranged in the form of a face-shared bioctahedron. The shared face consists of three of the platinum atoms. The fifth platinum atom is a cap on one of the Ru{sub 2}Pt triangles. Two hydride ligands are believed to bridge metals of the triangular faces on the opposite ends of the bioctahedron.

  9. Cluster synthesis. 38. Formation of high-nuclearity platinum-osmium cluster complexes. Synthesis, structural characterizations, and interrelationships of Pt[sub 4]Os[sub 6](CO)[sub 22](COD), Pt[sub 5]Os[sub 6](CO)[sub 21](COD)[sub 2], Pt[sub 4]Os[sub 6](CO)[sub 19](COD)[sub 2], and Pt[sub 7]Os[sub 6](CO)[sub 21](COD)[sub 2] (COD = cycloocta-1,5-diene)

    SciTech Connect

    Adams, R.D.; Jauching Lii; Wengan Wu )

    1992-06-10

    The chemistry of heteronuclear cluster complexes containing Pt has attracted a great deal of interest becasue of the importance of Pt alloys to the process of catalytic petroleum reforming. Three new high-nuclearity Pt-Os carbonyl cluster complexes Pt[sub 4]Os[sub 6](CO)[sub 22](COD) (2), Pt[sub 5]Os[sub 6](CO)[sub 21](COD)[sub 2] (3), and Pt[sub 4]Os[sub 6](CO)[sub 19](COD)[sub 2] (4) were obtained in 17%, 13%, and 9% yields, respectively, from the pyrolysis of Pt[sub 2]Os[sub 3](CO)[sub 10](COD)[sub 2] (1) under a CO atmosphere at 128C. Compounds 2-4 were characterized by IR, [sup 1]H NMR, and single-crystal X-ray diffraction analyses. Compound 2 consists of two Pt[sub 3]Os[sub 3] octahedra sharing a Pt[sub 3] triangular face. A Pt(COD) group caps one of the Os[sub 3] triangular faces. Compound 3 is structurally similar to compound 2 but has an additional Pt(COD) group capping one of the PtOs[sub 2] triangular faces. The cluster of compound 4 can be viewed as a meta-bicapped Pt[sub 2]Os[sub 4] octahedron with an additional Pt(COD) group capping a PtOs[sub 2] traingle to one of the capping groups on the octahedron and a Pt(COD) group bridging the Pt-Pt edge of the octahedron. Compound 2 was converted to 4 in 65% yield, when it was irradiated in the presence of COD. When compound 2 was treated with 1 equiv of trimethylamine N-oxide and 2 equiv of Pt(COD)[sub 2], compound 3 and a new higher nuclearity platinum-osmium carbonyl complex Pt[sub 7]Os[sub 6](CO)[sub 21](COD)[sub 2] (5; 8% yeild) were obtained. Compound 5 was characterized by a single-crystal X-ray diffraction analysis. It was formed by the loss of one CO from 2 and the addition of three Pt atoms and one COD ligand. Compound 2 was converted to the known compound Pt[sub 4]Os[sub 6](CO)[sub 21](COD)([mu]-H)[sub 2] in good yield (79%) by reacting with trimethylamine N-oxide and hydrogen.

  10. An enantioselective central-axial-central chiral element transfer process leading to a concise synthesis of (+)-sterpurene: Intramolecular Diels-Alder reactions of vinylallene sulfoxides

    SciTech Connect

    Gibbs, R.A.; Bartels, K.; Lee, R.W.K.; Okamura, W.H. )

    1989-05-10

    The intramolecular Diels-Alder (IMDA) reaction of vinylallene sulfoxide 19 as the diene component occurs in a rapid and stereoselective manner at room temperature to give tricyclic 20 in good yield. Sulfoxide 19 cyclizes {approximately} 140 times faster than the corresponding hydrocarbon 15a. It was also shown that gem-dimethyl substitution on the tether linking the vinylallene and vinyl group accelerates the rate of cyclization by only a factor of {approximately} 2.6. Treatment of enantiomerically enriched diene propargyl alcohol 6 with benzenesulfenyl chloride gave vinyallene sulfoxide 4 which cyclized in a highly enantio- and diastereoselective fashion to afford optically active tricyclic sulfoxide 5. Sulfoxide 5 was converted in two steps to the novel sesquiterpene fungal metabolite (+)-sterpurene, thus establishing its absolute configuration. By use of 2D NMR techniques, most of the proton and carbon signals in the {sup 1}H and {sup 13}C NMR spectra of sterpurene (8) and the precursor diene 33 were assigned.

  11. The sterols of Cucurbita moschata ("calabacita") seed oil.

    PubMed

    Rodriguez, J B; Gros, E G; Bertoni, M H; Cattaneo, P

    1996-11-01

    From the sterol fraction of seed oil from commercial Cucurbita moschata Dutch ("calabacita") delta 5 and delta 7 sterols having saturated and unsaturated side chain were isolated by chromatographic procedures and characterized by spectroscopic (1H and 13C-nuclear magnetic resonance, mass spectrometry) methods. The main components were identified as 24S-ethyl 5 alpha-cholesta-7,22E-dien-3 beta-ol (alpha-spinasterol); 24S-ethyl 5 alpha-cholesta-7,22E,25-trien-3 beta-ol (25-dehydrochondrillasterol); 24S-ethyl 5 alpha-cholesta-7,25-dien-3 beta-ol; 24R-ethyl-cholesta-7-en-3 beta-ol (delta 7-stigmastenol) and 24-ethyl-cholesta-7, 24(28)-dien-3 beta-ol (delta 7,24(28)-stigmastadienol). PMID:8934454

  12. Indolizinones as synthetic scaffolds: fundamental reactivity and the relay of stereochemical information†

    PubMed Central

    Hardin Narayan, Alison R.

    2012-01-01

    Indolizinones are under-explored N-heterocycles that react with exquisite chemo- and stereoselectivity. An exploration of the fundamental reactivity of these azabicycles demonstrates the potential to relay stereochemical information from the ring-fusion to newly formed stereocenters on the bicyclic core. The indolizinone diene undergoes selective hydrogenation and readily participates in Diels–Alder cycloadditions as well as ene reactions. The vinylogous amide embedded in the five-membered ring is resistant to reaction when the diene is in place. However, removal of the diene allows for diastereoselective hydrogenation of, and 1,4-additions to, the vinylogous amide. These fundamental reactions with indolizinones have provided a structurally diverse array of products that hold promise in the context of natural product synthesis. PMID:22072189

  13. Understanding reactivity and regioselectivity in Diels-Alder reactions of a sugar-derived dienophile bearing two competing EWGs. An experimental and computational study.

    PubMed

    Giri, Germán F; Sarotti, Ariel M; Spanevello, Rolando A

    2015-10-13

    The effect of an extra EWG in the reactivity and regioselectivity in Diels-Alder reactions of β-cyanolevoglucosenone and 4 different dienes was studied by a joint computational and experimental study. Conceptual DFT analysis successfully predicted an important enhancement in the reactivity, and correctly anticipated the regioselectivity in the reactions with isoprene. However, this static treatment failed when dealing the regiochemical preference of the reactions involving a substituted anthracene as diene. MPW1K/6-31G* calculations correctly reproduced the experimental observations. Based on the collected data, we found that when dealing with dienes and dienophiles with no clear electronically activated position, the ease of pyramidalization of the interacting atoms dictates the regioselectivity of the DA reaction. PMID:26318382

  14. An unusual mulinane diterpenoid from the Chilean plant Azorella trifurcata (Gaertn) Pers.

    PubMed

    Areche, Carlos; Sepulveda, Beatriz; San Martin, Aurelio; Garcia-Beltrán, Olimpo; Simirgiotis, Mario; Cañete, Alvaro

    2014-09-01

    Four new mulinane-type diterpenoids besides the known compounds mulin-11,13-dien-20-oic acid, 13α-hydroxyazorellane, 13β-hydroxyazorellane, mulinolic acid, azorellanol, and mulin-11,13-dien-18-acetoxy-16,20-dioic acid were isolated from the Chilean plant Azorella trifurcata. One of the new metabolites isolated, 7α-acetoxy-9-epi-13β-hydroxymulinane, possesses a new trans-syn-trans arrangement in a tricyclic ring system not previously encountered in nature. Among the mulinane diterpenoids isolated, mulin-11,13-dien-20-oic acid showed the gastroprotective effect on HCl-EtOH-induced gastric lesions in mice (ED50 = 55 mg kg(-1)). Regarding the mode of gastroprotective action for this active compound, its effect was reduced by pre-treatment of the mice with indomethacin and N-ethylmaleimide, suggesting that prostaglandins and sulfhydryl compounds are positively involved in the gastroprotective activity using this model. PMID:25008488

  15. Stereoselective synthesis of 11-phenylundeca-5Z,9Z-dienoic acid and investigation of its human topoisomerase I and IIα inhibitory activity.

    PubMed

    D'yakonov, Vladimir A; Dzhemileva, Lilya U; Makarov, Aleksey A; Mulukova, Alfiya R; Baev, Dmitry S; Khusnutdinova, Elza K; Tolstikova, Tatiana G; Dzhemilev, Usein M

    2015-06-01

    (5Z,9Z)-11-Phenylundeca-5,9-dienoic acid was stereoselectively synthesized, based on original cross-cyclomagnesiation of 2-(hepta-5,6-dien-1-yloxy)tetrahydro-2H-pyran and buta-2,3-dien-1-ylbenzene with EtMgBr in the presence of Cp2TiCl2 catalyst giving 2,5-dialkylidenemagnesacyclopentane in 86% yield. The acid hydrolysis of the product and the Jones oxidation of the resulting 2-{[(5Z,9Z)-11-phenylundeca-5,9-dien-1-yl]oxy}tetrahydro-2Н-pyran afforded (5Z,9Z)-11-phenylundeca-5,9-dienoic acid in an overall yield of 75%. A high inhibitory activity of the synthesized acid with respect to human topoisomerase I (hTop1) and II (hTop2α) was determined. PMID:25913198

  16. Sequential Diels–Alder/[3,3]-sigmatropic rearrangement reactions of β-nitrostyrene with 3-methyl-1,3-pentadiene

    PubMed Central

    Pipic, Alma; Zeller, Matthias; Tsetsakos, Panagiota

    2013-01-01

    Summary The tin(IV)-catalyzed reaction of β-nitrostyrene with (E)-3-methyl-1,3-pentadiene in toluene afforded two major nitronic ester cycloadducts in 27% and 29% yield that arise from the reaction at the less substituted diene double bond. Also present were four cycloadducts from the reaction at the higher substituted diene double bond, two of which were the formal cycloadducts of (Z)-3-methyl-1,3-pentadiene. A Friedel–Crafts alkylation product from the reaction of the diene, β-nitrostyrene, and toluene was also obtained in 10% yield. The tin(IV)-catalyzed reaction of β-nitrostyrene with (Z)-3-methyl-1,3-pentadiene in dichloromethane afforded four nitronic ester cycloadducts all derived from the reaction at the higher substituted double bond. One cycloadduct was isolated in 45% yield and two others are formal adducts of the E-isomer of the diene. The product formation in these reactions is consistent with a stepwise mechanism involving a zwitterionic intermediate. The initially isolated nitronic ester cycloadducts underwent tin(IV)-catalyzed interconversion, presumably via zwitterion intermediates. Cycloadducts derived from the reaction at the less substituted double bond of (E)-3-methyl-1,3-pentadiene underwent a [3,3]-sigmatropic rearrangement on heating to afford 4-nitrocyclohexenes. Cycloadducts derived from the reaction at the higher substituted diene double bond of either diene failed to undergo a thermal rearrangement. Rates and success of the rearrangement are consistent with a concerted mechanism possessing a dipolar transition state. An initial assessment of substituent effects on the rearrangement process is presented. PMID:24204426

  17. Incidence, distribution, seasonality, and demographic risk factors of Salmonella Enteritidis human infections in Ontario, Canada, 2007–2009

    PubMed Central

    2013-01-01

    Background In Canada, surveillance systems have highlighted the increasing trend of Salmonella enterica serovar Enteritidis (S. Enteritidis) human infections. Our study objectives were to evaluate the epidemiology of S. Enteritidis infections in Ontario using surveillance data from January 1, 2007 through December 31, 2009. Methods Annual age-and-sex-adjusted incidence rates (IRs), annual and mean age-adjusted sex-specific IRs, and mean age-and-sex-adjusted IRs by public health unit (PHU), were calculated for laboratory-confirmed S. Enteritidis cases across Ontario using direct standardization. Multivariable Poisson regression with PHU as a random effect was used to estimate incidence rate ratios (IRRs) of S. Enteritidis infections among years, seasons, age groups, and sexes. Results The annual age-and-sex-adjusted IR per 100,000 person-years was 4.4 [95% CI 4.0-4.7] in 2007, and 5.2 [95% CI 4.8-5.6] in both 2008 and 2009. The annual age-adjusted sex-specific IRs per 100,000 person-years ranged from 4.5 to 5.5 for females and 4.2 to 5.2 for males. The mean age-adjusted sex-specific IR was 5.1 [95% CI 4.8-5.4] for females and 4.8 [95% CI 4.5-5.1] for males. High mean age-and-sex-adjusted IRs (6.001-8.10) were identified in three western PHUs, one northern PHU, and in the City of Toronto. Regression results showed a higher IRR of S. Enteritidis infections in 2009 [IRR = 1.18, 95% CI 1.06-1.32; P = 0.003] and 2008 [IRR = 1.17, 95% CI 1.05-1.31; P = 0.005] compared to 2007. Compared to the fall season, a higher IRR of S. Enteritidis infections was observed in the spring [IRR = 1.14, 95% CI 1.01-1.29; P = 0.040]. Children 0–4 years of age (reference category), followed by children 5–9 years of age [IRR = 0.64, 95% CI 0.52-0.78; P < 0.001] had the highest IRRs. Adults ≥ 60 years of age and 40–49 years of age [IRR = 0.31, 95% CI 0.26-0.37; P < 0.001] had the lowest IRRs. Conclusions The study findings suggest that there was an increase in the incidence of S

  18. SNPs detection in DHPS-WDR83 overlapping genes mapping on porcine chromosome 2 in a QTL region for meat pH

    PubMed Central

    2013-01-01

    Background The pH is an important parameter influencing technological quality of pig meat, a trait affected by environmental and genetic factors. Several quantitative trait loci associated to meat pH are described on PigQTL database but only two genes influencing this parameter have been so far detected: Ryanodine receptor 1 and Protein kinase, AMP-activated, gamma 3 non-catalytic subunit. To search for genes influencing meat pH we analyzed genomic regions with quantitative effect on this trait in order to detect SNPs to use for an association study. Results The expressed sequences mapping on porcine chromosomes 1, 2, 3 in regions associated to pork pH were searched in silico to find SNPs. 356 out of 617 detected SNPs were used to genotype Italian Large White pigs and to perform an association analysis with meat pH values recorded in semimembranosus muscle at about 1 hour (pH1) and 24 hours (pHu) post mortem. The results of the analysis showed that 5 markers mapping on chromosomes 1 or 3 were associated with pH1 and 10 markers mapping on chromosomes 1 or 2 were associated with pHu. After False Discovery Rate correction only one SNP mapping on chromosome 2 was confirmed to be associated to pHu. This polymorphism was located in the 3’UTR of two partly overlapping genes, Deoxyhypusine synthase (DHPS) and WD repeat domain 83 (WDR83). The overlapping of the 3’UTRs allows the co-regulation of mRNAs stability by a cis-natural antisense transcript method of regulation. DHPS catalyzes the first step in hypusine formation, a unique amino acid formed by the posttranslational modification of the protein eukaryotic translation initiation factor 5A in a specific lysine residue. WDR83 has an important role in the modulation of a cascade of genes involved in cellular hypoxia defense by intensifying the glycolytic pathway and, theoretically, the meat pH value. Conclusions The involvement of the SNP detected in the DHPS/WDR83 genes on meat pH phenotypic variability and their

  19. A molecular symmetry analysis of the electronic states and transition dipole moments for molecules with two torsional degrees of freedom

    SciTech Connect

    Obaid, R.; Leibscher, M.

    2015-02-14

    We present a molecular symmetry analysis of electronic states and transition dipole moments for molecules which undergo large amplitude intramolecular torsions. The method is based on the correlation between the point group of the molecule at highly symmetric configurations and the molecular symmetry group. As an example, we determine the global irreducible representations of the electronic states and transition dipole moments for the quinodimethane derivative 2-[4-(cyclopenta-2,4-dien-1-ylidene)cyclohexa-2,5-dien-1-ylidene]-2H-1, 3-dioxole for which two torsional degrees of freedom can be activated upon photo-excitation and construct the resulting symmetry adapted transition dipole functions.

  20. Base-Free Conditions for Rhodium-Catalyzed Asymmetric Arylation To Produce Stereochemically Labile α-Aryl Ketones.

    PubMed

    Dou, Xiaowei; Lu, Yixin; Hayashi, Tamio

    2016-06-01

    The asymmetric arylation of 2,2-dialkyl cyclopent-4-ene-1,3-diones with aryl boronic acids was found to be efficiently catalyzed by a chiral diene-rhodium μ-chloro dimer, [{RhCl((R)-diene*)}2 ], in the absence of bases in toluene/H2 O to give 2,2-dialkyl 4-aryl cyclopentane-1,3-diones in high yields with high enantioselectivity. Such compounds can not be obtained with high enantiomeric purity under the standard basic conditions used for rhodium-catalyzed asymmetric arylation because the α-aryl ketone products undergo racemization under the basic conditions. PMID:27100902

  1. Small, beautiful and magnetically exotic: {V4W2}- and {V4W4}-type polyoxometalates.

    PubMed

    Rasmussen, Maren; Näther, Christian; van Leusen, Jan; Warzok, Ulrike; Schalley, Christoph A; Kögerler, Paul; Bensch, Wolfgang

    2016-06-28

    Minimal-nuclearity vanadato-tungstate clusters in [{V(IV)(dien)}4WO14]·4H2O () and [{V(IV)(dien)}4WO20]·6H2O () feature cores of edge-sharing WO6 octahedra, surrounded by a ring of four vanadyl groups. Surprisingly, the V(iv) centers in both and are ferromagnetically coupled, in contrast to all other known vanadato-polyoxotungstates featuring the ubiquituos V-O-W-O-V exchange pathways. PMID:27310000

  2. Terpenoids from Euphorbia pekinensis.

    PubMed

    Fang, Fu-Hu; Li, Wen-Hai; Han, Zheng-Zhi; Huang, Wen-Jun; Li, Dong-Xu; Zhao, Sha; Tang, Min-Hao; Yuan, Cheng-Shan

    2015-01-01

    Euphorpekone A (1) and euphorpekone B (2), two new diterpenoids, 3β-hydroxy-25-methyloxylanosta-8,23-diene, a new triterpenoid (3), together with a known triterpenoid, 3β,25-dihydroxylanosta-8,23-diene (4), were isolated from Euphorbia pekinensis Rupr. Their structures were elucidated on the basis of UV, IR, 1D ((1)H, (13)C, NOE) and 2D ((1)H-(1)H COSY, HSQC, HMBC) NMR, HR-ESI-MS, X-ray diffraction analysis, and CD method. PMID:26654567

  3. Enantio- and periselective nitroalkene Diels-Alder reactions catalyzed by helical-chiral hydrogen bond donor catalysts.

    PubMed

    Peng, Zhili; Narcis, Maurice J; Takenaka, Norito

    2013-01-01

    Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio- and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst was investigated by exploiting readily available 5-substituted pentamethylcyclopentadienes. The catalyst was found to tolerate dienes with different steric demands as well as dienes substituted with heteroatoms. The synthetic utility of 5-substituted pentamethylcyclopentadienes is rather limited, and thus we have developed a three-step route to 1,4,5,5-tetrasubstituted cyclopentadienes from commercially available ketones. PMID:23966083

  4. 5,8-Epidioxysterols and related derivatives from a Chinese soft coral Sinularia flexibilis.

    PubMed

    Yu, Shanjiang; Deng, Zhiwei; van Ofwegen, Leen; Proksch, Peter; Lin, Wenhan

    2006-11-01

    Chromatographic separation of the methanolic extract of the marine soft coral, Sinularia flexibilis, resulted in the isolation and characterization of four new sterols, 5alpha,8alpha-epidioxygorgosta-6-en-3beta-ol (1), 5alpha,8alpha-epidioxygorgosta-6,9(11)-dien-3beta-ol (2), 22alpha,28-epidioxycholesta-5,23(E)-dien-3beta-ol (3) and its C-22 epimer (4), along with nine known sterols. The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, 1H and 13C NMR, HMQC, HMBC, and NOESY) analyses. PMID:16930652

  5. Reversible Thermoset Adhesives

    NASA Technical Reports Server (NTRS)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  6. Silver Nanoparticle-Catalyzed Diels-Alder Cycloadditions of 2′-Hydroxychalcones

    PubMed Central

    Cong, Huan; Becker, Clinton F.; Elliott, Sean J.; Grinstaff, Mark W.; Porco, John A.

    2010-01-01

    Metal nanoparticles are currently being employed as catalysts for a number of classical chemical transformations. In contrast, identification of novel reactions of nanoparticles, especially towards the synthesis of complex natural products and derivatives, is highly underdeveloped and represents a bourgeoning area in chemical synthesis. Herein, we report silica-supported silver nanoparticles as solid, recyclable catalysts for Diels-Alder cycloadditions of 2′-hydroxychalcones and dienes in high yield and turnover number. The use of silver nanoparticle catalysts is further demonstrated by the total synthesis of the cytotoxic natural product panduratin A employing a highly electron-rich dienophile and Lewis acid-sensitive diene. PMID:20443601

  7. Alienusolin, a new 4α-deoxyphorbol ester derivative, and crotonimide C, a new glutarimide alkaloid from the Kenyan Croton alienus.

    PubMed

    Ndunda, Beth; Langat, Moses K; Wanjohi, John M; Midiwo, Jacob O; Kerubo, Leonidah O

    2013-12-01

    Two novel compounds, alienusolin, a 4α-deoxyphorbol ester (1), crotonimide C, a glutarimide alkaloid derivative (2), and ten known compounds, julocrotine (3), crotepoxide (4), monodeacetyl crotepoxide (5), dideacetylcrotepoxide, (6), β-senepoxide (7), α-senepoxide (8), (+)-(2S,3R-diacetoxy-1-benzoyloxymethylenecyclohex-4,6-diene (9), benzyl benzoate (10), acetyl aleuritolic (11), and 24-ethylcholesta-4,22-dien-3-one (12) were isolated from the Kenyan Croton alienus. The structures of the compounds were determined using NMR, GCMS, and HRESIMS studies. PMID:24356872

  8. Copper(II)-catalyzed room temperature aerobic oxidation of hydroxamic acids and hydrazides to acyl-nitroso and azo intermediates, and their Diels-Alder trapping.

    PubMed

    Chaiyaveij, Duangduan; Cleary, Leah; Batsanov, Andrei S; Marder, Todd B; Shea, Kenneth J; Whiting, Andrew

    2011-07-01

    CuCl(2), in the presence of a 2-ethyl-2-oxazoline ligand, is an effective catalyst for the room temperature, aerobic oxidation of hydroxamic acids and hydrazides, to acyl-nitroso and azo dienophiles respectively, which are efficiently trapped in situ via both inter- and intramolecular hetero-Diels-Alder reactions with dienes. Both inter- and intramolecular variants of the Diels-Alder reaction are suitable under the reaction conditions using a variety of solvents. Under the same conditions, an acyl hydrazide was also oxidized to give an acyl-azo dienophile which was trapped intramolecularly by a diene. PMID:21644530

  9. Cucurbitane-type triterpenes from Citrullus lanatus (watermelon) seeds.

    PubMed

    Kikuchi, Takashi; Okada, Rina; Harada, Yu; Ikushima, Kenji; Yamakawa, Takahiro; Yamada, Takeshi; Tanaka, Reiko

    2013-10-01

    Two new cucurbitane-type triterpenes, 24-hydroperoxycucurbita-5,25-dien-3beta-ol (1) and 25-hydroperoxycucurbita-5,23-dien-3beta-ol (2), were isolated from a MeOH extract of Citrullus lanatus seeds. Compounds 1 and 2 exhibited moderate cytotoxic activities with IC50 values of 33.4-52.4 microM against HL-60 (human leukemia), P388 (murine leukemia), and L1210 (murine leukemia) cells. Compound 1 showed melanogenesis inhibitory activity (melanin content 80.0 %) with low cytotoxicity (cell viability 97.6%) at a low concentration (10 microM). PMID:24354176

  10. An unexpected double Diels-Alder reaction of (E)-2-bromo-4-aryl-1,3-pentadiene involving [1,5]-hydrogen migration and HBr elimination: synthesis of bicyclo[2.2.2]octene derivatives.

    PubMed

    Huang, Pingping; Liu, Lingyan; Chang, Weixing; Li, Jing

    2015-03-01

    An unexpected double Diels-Alder (DDA) reaction of (E)-2-bromo-4-aryl-1,3-pentadiene was developed and resulted in a series of "butterfly-like" bicyclo[2.2.2]octene derivatives in moderate to good yields without the need for a metal catalyst. The proposed mechanism involves a [1,5]-sigmatropic hydrogen migration and HBr elimination. Through this decisive [1,5]-hydrogen shift step, the electronic properties and steric hindrance of the conjugated diene substrate are completely altered and the DDA reaction of this potential diene synthon is successfully achieved. PMID:25620015

  11. Prevalence of Opisthorchis viverrini-Like Fluke Infection in Ducks in Binh Dinh Province, Central Vietnam.

    PubMed

    Dao, Thanh Thi Ha; Abatih, Emmanuel Nji; Nguyen, Thanh Thi Giang; Tran, Ha Thi Lam; Gabriël, Sarah; Smit, Suzanne; Le, Phap Ngoc; Dorny, Pierre

    2016-06-01

    Following the first report of Opisthorchis viverrini infection in a domestic duck in Phu My District of Binh Dinh Province, Central Vietnam, many other cases were observed in the province. We determined the infection rate and intensity of O. viverrini infection in ducks in 4 districts of the province. A total of 178 ducks were randomly selected from 34 farms for examination of flukes in the liver and gall bladder. An infection rate of 34.3% (range 20.7-40.4% among districts) was found; the intensity of infection was 13.8 worms per infected duck (range 1-100). These findings show the role of ducks as a host for O. viverrini, duck genotype, which is sympatric with the human O. viverrini genotype in this province. It also stresses the need for investigations on the zoonotic potential and the life cycle of this parasite. PMID:27417094

  12. A New Representative of Star-Shaped Fungi: Astraeus sirindhorniae sp. nov. from Thailand

    PubMed Central

    Phosri, Cherdchai; Watling, Roy; Suwannasai, Nuttika; Wilson, Andrew; Martín, María P.

    2014-01-01

    Phu Khieo Wildlife Sanctuary (PKWS) is a major hotspot of biological diversity in Thailand but its fungal diversity has not been thouroughly explored. A two-year macrofungal study of this remote locality has resulted in the recognition of a new species of a star-shaped gasteroid fungus in the genus Astraeus. This fungus has been identified based on a morphological approach and the molecular study of five loci (LSU nrDNA, 5.8S nrDNA, RPB1, RPB2 and EF1-a). Multigene phylogenetic analysis of this new species places it basal relative to other Astraeus, providing additional evidence for the SE Asian orgin of the genus. The fungus is named in honour of Her Majesty Princess Sirindhorn on the occasion the 84th birthday of her father, who have both been supportive of natural heritage studies in Thailand. PMID:24806455

  13. Microdeletions in patients with gusher-associated, X-linked mixed deafness (DFN3)

    PubMed Central

    Bach, I.; Brunner, H. G.; Beighton, P.; Ruvalcaba, R. H. A.; Reardon, W.; Pembrey, M. E.; van der Velde-Visser, S. D.; Bruns, G. A. P.; Cremers, C. W. R. J.; Cremers, F. P. M.; Ropers, H.-H.

    1992-01-01

    Employing various probes from the proximal part of the Xq21 region, which is known to harbor the DFN3 gene, we have investigated 13 unrelated male probands with X-linked deafness, to detect possible deletions. For two of these patients, microdeletions could be detected by using probe pHU16 (DXS26). One of these deletions also encompasses locus DXS169, indicating that it extends farther toward the centromere. The presence of normal hybridization patterns in the DNA of 25 unrelated control males suggests that these deletions are the primary cause of progressive mixed deafness in these patients. If so, their molecular characterization may pave the way for the identification and isolation of the corresponding gene. ImagesFigure 2 PMID:1609803

  14. A simple rule based model for scheduling farm management operations in SWAT

    NASA Astrophysics Data System (ADS)

    Schürz, Christoph; Mehdi, Bano; Schulz, Karsten

    2016-04-01

    For many interdisciplinary questions at the watershed scale, the Soil and Water Assessment Tool (SWAT; Arnold et al., 1998) has become an accepted and widely used tool. Despite its flexibility, the model is highly demanding when it comes to input data. At SWAT's core the water balance and the modeled nutrient cycles are plant growth driven (implemented with the EPIC crop growth model). Therefore, land use and crop data with high spatial and thematic resolution, as well as detailed information on cultivation and farm management practices are required. For many applications of the model however, these data are unavailable. In order to meet these requirements, SWAT offers the option to trigger scheduled farm management operations by applying the Potential Heat Unit (PHU) concept. The PHU concept solely takes into account the accumulation of daily mean temperature for management scheduling. Hence, it contradicts several farming strategies that take place in reality; such as: i) Planting and harvesting dates are set much too early or too late, as the PHU concept is strongly sensitivity to inter-annual temperature fluctuations; ii) The timing of fertilizer application, in SWAT this often occurs simultaneously on the same date in in each field; iii) and can also coincide with precipitation events. Particularly, the latter two can lead to strong peaks in modeled nutrient loads. To cope with these shortcomings we propose a simple rule based model (RBM) to schedule management operations according to realistic farmer management practices in SWAT. The RBM involves simple strategies requiring only data that are input into the SWAT model initially, such as temperature and precipitation data. The user provides boundaries of time periods for operation schedules to take place for all crops in the model. These data are readily available from the literature or from crop variety trials. The RBM applies the dates by complying with the following rules: i) Operations scheduled in the

  15. A new interstitial ostracod species of the genus Paracobanocythere from Vietnam, with mitochondrial CO1 sequence data of three Asian species.

    PubMed

    Tanaka, Hayato; Dung, Le Doan; Higashi, Ryouichi; Tsukagoshi, Akira

    2016-01-01

    This study is a first report of an interstitial ostracod from Southeast Asia. The ostracod species, Paracobanocythere vietnamensis sp. n., was found in the marine interstitial environment of Phu Quoc Island, Vietnam. Thus far, three species of this genus have been described. The morphology of the carapace as well as the appendages of this new species are quite similar to Paracobanocythere hawaiiensis and Paracobanocythere watanabei. However, we found that they could be easily distinguished according to the morphology of the male copulatory organ. Additionally, we estimated the evolutionary distances among these three species based on nucleotide and amino acid sequences of the mitochondrial CO1 gene. Similar morphologies of carapaces and appendages, and relatively small evolutionary distances according to CO1 between Paracobanocythere vietnamensis sp. n. and Paracobanocythere watanabei suggest that these two species are very closely related. PMID:27006603

  16. A new interstitial ostracod species of the genus Paracobanocythere from Vietnam, with mitochondrial CO1 sequence data of three Asian species

    PubMed Central

    Tanaka, Hayato; Dung, Le Doan; Higashi, Ryouichi; Tsukagoshi, Akira

    2016-01-01

    Abstract This study is a first report of an interstitial ostracod from Southeast Asia. The ostracod species, Paracobanocythere vietnamensis sp. n., was found in the marine interstitial environment of Phu Quoc Island, Vietnam. Thus far, three species of this genus have been described. The morphology of the carapace as well as the appendages of this new species are quite similar to Paracobanocythere hawaiiensis and Paracobanocythere watanabei. However, we found that they could be easily distinguished according to the morphology of the male copulatory organ. Additionally, we estimated the evolutionary distances among these three species based on nucleotide and amino acid sequences of the mitochondrial CO1 gene. Similar morphologies of carapaces and appendages, and relatively small evolutionary distances according to CO1 between Paracobanocythere vietnamensis sp. n. and Paracobanocythere watanabei suggest that these two species are very closely related. PMID:27006603

  17. Prevalence of Opisthorchis viverrini-Like Fluke Infection in Ducks in Binh Dinh Province, Central Vietnam

    PubMed Central

    Dao, Thanh Thi Ha; Abatih, Emmanuel Nji; Nguyen, Thanh Thi Giang; Tran, Ha Thi Lam; Gabriël, Sarah; Smit, Suzanne; Le, Phap Ngoc; Dorny, Pierre

    2016-01-01

    Following the first report of Opisthorchis viverrini infection in a domestic duck in Phu My District of Binh Dinh Province, Central Vietnam, many other cases were observed in the province. We determined the infection rate and intensity of O. viverrini infection in ducks in 4 districts of the province. A total of 178 ducks were randomly selected from 34 farms for examination of flukes in the liver and gall bladder. An infection rate of 34.3% (range 20.7-40.4% among districts) was found; the intensity of infection was 13.8 worms per infected duck (range 1-100). These findings show the role of ducks as a host for O. viverrini, duck genotype, which is sympatric with the human O. viverrini genotype in this province. It also stresses the need for investigations on the zoonotic potential and the life cycle of this parasite. PMID:27417094

  18. Monitoring of rice cropping intensity in the upper Mekong Delta, Vietnam using time-series MODIS data

    NASA Astrophysics Data System (ADS)

    Chen, C. F.; Son, N. T.; Chang, L. Y.

    2012-01-01

    Information on rice growing areas is important for policymakers to devise agricultural plans. This research explores the monitoring of rice cropping intensity in the upper Mekong Delta, Vietnam (from 2001 to 2007) using time-series MODIS NDVI 250-m data. Data processing includes three steps: (1) noise is filtered from the time-series NDVI data using empirical mode decomposition (EMD); (2) endmembers are extracted from the filtered time-series data and trained in a linear mixture model (LMM) for classification of rice cropping systems; and (3) classification results are verified by comparing them with the ground-truth and statistical data. The results indicate that EMD is a good filter for noise removal from the time-series data. The classification results confirm the validity of LMM, giving an overall accuracy of 90.1% and a Kappa coefficient of 0.7. The lowest producer and user accuracies were associated with single crop rain-fed rice class due to the mixed pixel problems. A strong yearly correlation at the district level was revealed in the MODIS-derived areas (R2 ⩾ 0.9). Investigation of interannual changes in rice cropping intensity from 2001 to 2007 showed a remarkable conversion from double to triple crop irrigated rice from 2001 to 2003, especially in the Thoai Son and Phu Tan districts. A big conversion from triple crop rice back to double crop rice cultivation was also observed in Phu Tan from 2005 to 2006. These changes were verified by visual interpretation of Landsat images and examination of NDVI profiles.

  19. Effects of carbazole-degradative plasmid pCAR1 on biofilm morphology in Pseudomonas putida KT2440.

    PubMed

    Lee, Seunguk; Takahashi, Yurika; Oura, Hiromu; Suzuki-Minakuchi, Chiho; Okada, Kazunori; Yamane, Hisakazu; Nomura, Nobuhiko; Nojiri, Hideaki

    2016-04-01

    Bacteria typically form biofilms under natural conditions. To elucidate the effect of the carriage of carbazole-degradative plasmid pCAR1 on biofilm formation by host bacteria, we compared the biofilm morphology, using confocal laser scanning microscopy, of three pCAR1-free and pCAR1-carrying Pseudomonas hosts: P. putida KT2440, P. aeruginosa PAO1 and P. fluorescens Pf0-1. Although pCAR1 did not significantly affect biofilm formation by PAO1 or Pf0-1, pCAR1-carrying KT2440 became filamentous and formed flat biofilms, whereas pCAR1-free KT2440 formed mushroom-like biofilms. pCAR1 contains three genes encoding nucleoid-associated proteins (NAPs), namely, Pmr, Pnd and Phu. The enhanced filamentous morphology was observed in two double mutants [KT2440(pCAR1ΔpmrΔpnd) and KT2440(pCAR1ΔpmrΔphu)], suggesting that these NAPs are involved in modulating the filamentous phenotype. Transcriptome analyses of the double mutants identified 32 candidate genes that may be involved in filamentation of KT2440. Overexpression of PP_2193 in KT2440 induced filamentation and overexpression of PP_0308 or PP_0309 in KT2440(pCAR1) enhanced filamentation of cells over time. This suggests that pCAR1 induces development of an abnormal filamentous morphology by KT2440 via a process involving overexpression of several genes, such as PP_2193. In addition, pCAR1-encoded NAPs partly suppress too much filamentation of KT2440(pCAR1) by repressing transcription of some genes, such as PP_0308 and PP_0309. PMID:26743211

  20. Bruising in Slaughter Cattle and Its Relationship with Creatine Kinase Levels and Beef Quality as Affected by Animal Related Factors

    PubMed Central

    Mpakama, T.; Chulayo, A. Y.; Muchenje, V.

    2014-01-01

    The objective of the study was to determine the effects of animal related factors on bruising in slaughter cattle, creatine kinase (CK) and beef quality. Three hundred and twenty one cattle from three breeds (108 Bonsmara, 130 Beefmaster and 83 Brahman) were used in this study. The animals were grouped as follows: Group 1 (16 months old), Group 2 (18 months old) and Group 3 (24 months old). At exsanguinations, blood samples for CK determination were collected using disposable vacutainer tubes. Muscularis longissimus thoracis et lumborum (LTL) was collected 24 h after slaughter to determine the colour (L*, a*, and b*) and ultimate pH (pHu) of beef. Breed, sex and age had significant effects (p<0.05) on bruising score, CK levels and beef quality. Bonsmara breed had the highest (80%) bruising score percentage, CK (705.3±80.57 U/L) and pHu (6.3±0.05) values while the Bonsmara had the highest L* (24.8±0.78) a* (17.5±0.53) and b* (12.8±0.53) values. Higher CK levels were also observed in winter compared to summer, spring and autumn respectively. Therefore, animal factors (sex, breed and animal age at slaughter) contribute to the development of bruises and have an effect on the levels of CK and meat quality. It was also concluded that there is no significant relationship between meat parameters (L,* a*, and b*) and CK levels. PMID:25050007

  1. Bruising in slaughter cattle and its relationship with creatine kinase levels and beef quality as affected by animal related factors.

    PubMed

    Mpakama, T; Chulayo, A Y; Muchenje, V

    2014-05-01

    The objective of the study was to determine the effects of animal related factors on bruising in slaughter cattle, creatine kinase (CK) and beef quality. Three hundred and twenty one cattle from three breeds (108 Bonsmara, 130 Beefmaster and 83 Brahman) were used in this study. The animals were grouped as follows: Group 1 (16 months old), Group 2 (18 months old) and Group 3 (24 months old). At exsanguinations, blood samples for CK determination were collected using disposable vacutainer tubes. Muscularis longissimus thoracis et lumborum (LTL) was collected 24 h after slaughter to determine the colour (L*, a*, and b*) and ultimate pH (pHu) of beef. Breed, sex and age had significant effects (p<0.05) on bruising score, CK levels and beef quality. Bonsmara breed had the highest (80%) bruising score percentage, CK (705.3±80.57 U/L) and pHu (6.3±0.05) values while the Bonsmara had the highest L* (24.8±0.78) a* (17.5±0.53) and b* (12.8±0.53) values. Higher CK levels were also observed in winter compared to summer, spring and autumn respectively. Therefore, animal factors (sex, breed and animal age at slaughter) contribute to the development of bruises and have an effect on the levels of CK and meat quality. It was also concluded that there is no significant relationship between meat parameters (L,* a*, and b*) and CK levels. PMID:25050007

  2. A calibration procedure to improve global rice yield simulations with EPIC

    SciTech Connect

    Xiong, Wei; Balkovic, Juraj; van der Velde, M.; Zhang, Xuesong; Izaurralde, Roberto C.; Skalsky, Rastislav; Lin, Erda; Mueller, Nathan; Obersteiner, Michael

    2014-02-01

    Crop models are increasingly used to assess impacts of climate change/variability and management practices on productivity and environmental performance of alternative cropping systems. Calibration is an important procedure to improve reliability of model simulations, especially for large area applications. However, global-scale crop model calibration has rarely been exercised due to limited data availability and expensive computing cost. Here we present a simple approach to calibrate Environmental Policy Integrated Climate (EPIC) model for a global implementation of rice. We identify four parameters (potential heat unit – PHU, planting density – PD, harvest index – HI, and biomass energy ratio – BER) and calibrate them regionally to capture the spatial pattern of reported rice yield in 2000. Model performance is assessed by comparing simulated outputs with independent FAO national data. The comparison demonstrates that the global calibration scheme performs satisfactorily in reproducing the spatial pattern of rice yield, particularly in main rice production areas. Spatial agreement increases substantially when more parameters are selected and calibrated, but with varying efficiencies. Among the parameters, PHU and HI exhibit the highest efficiencies in increasing the spatial agreement. Simulations with different calibration strategies generate a pronounced discrepancy of 5–35% in mean yields across latitude bands, and a small to moderate difference in estimated yield variability and yield changing trend for the period of 1981–2000. Present calibration has little effects in improving simulated yield variability and trends at both regional and global levels, suggesting further works are needed to reproduce temporal variability of reported yields. This study highlights the importance of crop models’ calibration, and presents the possibility of a transparent and consistent up scaling approach for global crop simulations given current availability of

  3. Sequence diversity in coding regions of candidate genes in the glycoalkaloid biosynthetic pathway of wild potato species.

    PubMed

    Manrique-Carpintero, Norma C; Tokuhisa, James G; Ginzberg, Idit; Holliday, Jason A; Veilleux, Richard E

    2013-09-01

    Natural variation in five candidate genes of the steroidal glycoalkaloid (SGA) metabolic pathway and whole-genome single nucleotide polymorphism (SNP) genotyping were studied in six wild [Solanum chacoense (chc 80-1), S. commersonii, S. demissum, S. sparsipilum, S. spegazzinii, S. stoloniferum] and cultivated S. tuberosum Group Phureja (phu DH) potato species with contrasting levels of SGAs. Amplicons were sequenced for five candidate genes: 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 and 2 (HMG1, HMG2) and 2.3-squalene epoxidase (SQE) of primary metabolism, and solanidine galactosyltransferase (SGT1), and glucosyltransferase (SGT2) of secondary metabolism. SNPs (n = 337) producing 354 variations were detected within 3.7 kb of sequenced DNA. More polymorphisms were found in introns than exons and in genes of secondary compared to primary metabolism. Although no significant deviation from neutrality was found, dN/dS ratios < 1 and negative values of Tajima's D test suggested purifying selection and genetic hitchhiking in the gene fragments. In addition, patterns of dN/dS ratios across the SGA pathway suggested constraint by natural selection. Comparison of nucleotide diversity estimates and dN/dS ratios showed stronger selective constraints for genes of primary rather than secondary metabolism. SNPs (n = 24) with an exclusive genotype for either phu DH (low SGA) or chc 80-1 (high SGA) were identified for HMG2, SQE, SGT1 and SGT2. The SolCAP 8303 Illumina Potato SNP chip genotyping revealed eight informative SNPs on six pseudochromosomes, with homozygous and heterozygous genotypes that discriminated high, intermediate and low levels of SGA accumulation. These results can be used to evaluate SGA accumulation in segregating or association mapping populations. PMID:23853090

  4. Sequence Diversity in Coding Regions of Candidate Genes in the Glycoalkaloid Biosynthetic Pathway of Wild Potato Species

    PubMed Central

    Manrique-Carpintero, Norma C.; Tokuhisa, James G.; Ginzberg, Idit; Holliday, Jason A.; Veilleux, Richard E.

    2013-01-01

    Natural variation in five candidate genes of the steroidal glycoalkaloid (SGA) metabolic pathway and whole-genome single nucleotide polymorphism (SNP) genotyping were studied in six wild [Solanum chacoense (chc 80-1), S. commersonii, S. demissum, S. sparsipilum, S. spegazzinii, S. stoloniferum] and cultivated S. tuberosum Group Phureja (phu DH) potato species with contrasting levels of SGAs. Amplicons were sequenced for five candidate genes: 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 and 2 (HMG1, HMG2) and 2.3-squalene epoxidase (SQE) of primary metabolism, and solanidine galactosyltransferase (SGT1), and glucosyltransferase (SGT2) of secondary metabolism. SNPs (n = 337) producing 354 variations were detected within 3.7 kb of sequenced DNA. More polymorphisms were found in introns than exons and in genes of secondary compared to primary metabolism. Although no significant deviation from neutrality was found, dN/dS ratios < 1 and negative values of Tajima’s D test suggested purifying selection and genetic hitchhiking in the gene fragments. In addition, patterns of dN/dS ratios across the SGA pathway suggested constraint by natural selection. Comparison of nucleotide diversity estimates and dN/dS ratios showed stronger selective constraints for genes of primary rather than secondary metabolism. SNPs (n = 24) with an exclusive genotype for either phu DH (low SGA) or chc 80-1 (high SGA) were identified for HMG2, SQE, SGT1 and SGT2. The SolCAP 8303 Illumina Potato SNP chip genotyping revealed eight informative SNPs on six pseudochromosomes, with homozygous and heterozygous genotypes that discriminated high, intermediate and low levels of SGA accumulation. These results can be used to evaluate SGA accumulation in segregating or association mapping populations. PMID:23853090

  5. Structures and biological activities of triterpenes and sesquiterpenes obtained from Russula lepida.

    PubMed

    Lee, Jong-Soo; Maarisit, Wilmar; Abdjul, Delfly B; Yamazaki, Hiroyuki; Takahashi, Ohgi; Kirikoshi, Ryota; Kanno, Syu-Ichi; Namikoshi, Michio

    2016-07-01

    A seco-cucurbitane triterpene and two aristolane sesquiterpenes, named (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid, (+)-1,2-didehydro-9-hydroxy-aristlone, and (+)-12-hydroxy-aristlone, were isolated from fruiting bodies of the medicinal mushroom Russula lepida, together with (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid and (+)-aristlone. The structures of the first three compounds, including their absolute configurations, were assigned on the basis of their NMR and ECD spectra. Two seco-cucurbitane triterpenes, (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid and (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid, inhibited the activity of protein tyrosine phosphatase 1B (PTP1B), with IC50 values of 20.3 and 0.4μM, respectively. All isolated compounds did not show cytotoxicity against human cancer cell lines, Huh-7 (hepatoma) and EJ-1 (bladder), at 50μM. PMID:27066716

  6. Antioxidant activity of banana flavonoids.

    PubMed

    Vijayakumar, S; Presannakumar, G; Vijayalakshmi, N R

    2008-06-01

    The antioxidant activity of flavonoids from banana (Musa paradisiaca) was studied in rats fed normal as well as high fat diets. Concentrations of peroxidation products namely malondialdehyde, hydroperoxides and conjugated diens were significantly decreased whereas the activities of catalase and superoxide dismutase were enhanced significantly. Concentrations of glutathione were also elevated in the treated animals. PMID:18329185

  7. Synthesis of Lepadiformine Using a Hydroamination Transform.

    PubMed

    Tabor, M Greg; Shenvi, Ryan A

    2015-12-01

    Dissection of lepadiformine by a double hydroamination transform affords a simple achiral amino diene. This reaction is accomplished in the forward sense by amine-directed hydroboration and an oxidative alkyl shift to nitrogen, both of which occur with high stereoselectivity to generate three stereogenic centers and the lepadiformine skeleton. PMID:26584132

  8. New cucurbitacin glycosides from Picrorhiza kurrooa.

    PubMed

    Stuppner, H; Wagner, H

    1989-12-01

    From the roots of Picrorhiza kurrooa Royle and Benth., seven cucurbitacin glycosides have been isolated and structurally elucidated mainly by NMR and mass spectroscopy. Four of them (4, 5, 6, 7) are new and two, the 2-O-glycoside of cucurbitacin B (25-acetoxy-2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norl anosta-5, 23-diene-3,11,22-trione) and the 2-O-glucoside of 23,24 didydrocucurbitacin B (25-acetoxy-2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norl anost-5-ene-3, 11-22-trione) were so far not reported as constituents of this plant. The four new cucurbitacins could be identified as 2-beta-glucosyloxy-3,16,20,25-tetrahydroxy-9-methyl-19-norlanos ta-5, 23-diene-22-one, 2-beta-glucosyloxy-3,16,20,25-tetrahydroxy-9-methyl-19-norlanos t-5-ene-22-one, the 2-O-glucoside of cucurbitacin Q (25-acetoxy-2-beta-glucosyloxy-3,16,20-trihydroxy-9-methyl-19-n orlanosta-5, 23-diene-11,22-dione), and the 2-O-glucoside of deacetoxycucurbitacin B (2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norlanosta-5 , 24-diene-3,11,22-trione). PMID:2616673

  9. Teaching Experiment: The Effect of Manipulatives in Second Graders' Learning of Mathematics, Volume I. PMDC Technical Report No. 11.

    ERIC Educational Resources Information Center

    Behr, Merlyn J.

    This teaching experiment investigated variables which affect how well children learn from manipulative aids and how to use such aids in teaching mathematics. Five small groups from one second-grade classroom were stratified by achievement and taught using (1) counting sticks; (2) Dienes blocks; (3) abacus; (4) all three materials; or (5) counting…

  10. New library of aminosulfonyl-tagged Hoveyda–Grubbs type complexes: Synthesis, kinetic studies and activity in olefin metathesis transformations

    PubMed Central

    Borré, Etienne; Caijo, Frederic

    2010-01-01

    Summary Seven novel Hoveyda–Grubbs precatalysts bearing an aminosulfonyl function are reported. Kinetic studies indicate an activity enhancement compared to Hoveyda’s precatalyst. A selection of these catalysts was investigated with various substrates in ring-closing metathesis of dienes or enynes and cross metathesis. The results demonstrate that these catalysts show a good tolerance to various chemical functions. PMID:21165173

  11. Synthesis of the Reported Pyranonaphthoquinone Structure of the Indoleamine-2,3-dioxygenase Inhibitor Annulin B by Regioselective Diels-Alder Reaction.

    PubMed

    Inman, Martyn; Carvalho, Catarina; Lewis, William; Moody, Christopher J

    2016-09-01

    Annulin B, isolated from the marine hydroid isolated from Garveia annulata, is a potent inhibitor of the tryptophan catabolizing enzyme indoleamine-2,3-dioxygenase (IDO). A synthesis of the reported pyranonaphthoquinone structure is described, in which the key step is a regioselective Diels-Alder reaction between a pyranobenzoquinone dienophile and a silyl ketene acetal diene. PMID:27513176

  12. Increase in cellular pool of low-molecular-weight iron during ethanol metabolism in rat hepatocyte cultures. Relationship with lipid peroxidation.

    PubMed

    Sergent, O; Morel, I; Cogrel, P; Chevanne, M; Pasdeloup, N; Brissot, P; Lescoat, G; Cillard, P; Cillard, J

    1995-01-01

    Ethanol-induced lipid peroxidation was studied in primary rat hepatocyte cultures supplemented with ethanol at the concentration of 50 mM. Lipid peroxidation was assessed by two indices: (1) conjugated dienes by second-derivative UV spectroscopy in lipid extract of hepatocytes (intracellular content), and (2) free malondialdehyde (MDA) by HPLC-UV detection and quantitation for the incubation medium (extracellular content). In cultures supplemented with ethanol, free MDA increased significantly in culture media, whereas no elevation of conjugated diene level was observed in the corresponding hepatocytes. The cellular pool of low-mol-wt (LMW) iron was also evaluated in the hepatocytes using an electron spin resonance procedure. An early increase of intracellular LMW iron (< or = 1 hr) was observed in ethanol-supplemented cultures; it was inhibited by 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, whereas alpha-tocopherol, which prevented lipid peroxidation, did not inhibit the increase of LMW iron. Therefore, the LMW iron elevation was the result of ethanol metabolism and was not secondarily induced by lipid hydroperoxides. Thus, ethanol caused lipid peroxidation in rat hepatocytes as shown by the increase of free MDA, although no conjugated diene elevation was detected. During ethanol metabolism, an increase in cellular LMW iron was observed that could enhance conjugated diene degradation. PMID:7779546

  13. Cobalt-Catalyzed [2π + 2π] Cycloadditions of Alkenes: Scope, Mechanism, and Elucidation of Electronic Structure of Catalytic Intermediates.

    PubMed

    Schmidt, Valerie A; Hoyt, Jordan M; Margulieux, Grant W; Chirik, Paul J

    2015-06-24

    Aryl-substituted bis(imino)pyridine cobalt dinitrogen compounds, ((R)PDI)CoN2, are effective precatalysts for the intramolecular [2π + 2π] cycloaddition of α,ω-dienes to yield the corresponding bicyclo[3.2.0]heptane derivatives. The reactions proceed under mild thermal conditions with unactivated alkenes, tolerating both amine and ether functional groups. The overall second order rate law for the reaction, first order with respect to both the cobalt precatalyst and the substrate, in combination with electron paramagnetic resonance (EPR) spectroscopic studies established the catalyst resting state as dependent on the identity of the precatalyst and diene substrate. Planar S = ½ κ(3)-bis(imino)pyridine cobalt alkene and tetrahedral κ(2)-bis(imino)pyridine cobalt diene complexes were observed by EPR spectroscopy and in the latter case structurally characterized. The hemilabile chelate facilitates conversion of a principally ligand-based singly occupied molecular orbital (SOMO) in the cobalt dinitrogen and alkene compounds to a metal-based SOMO in the diene intermediates, promoting C-C bond-forming oxidative cyclization. Structure-activity relationships on bis(imino)pyridine substitution were also established with 2,4,6-tricyclopentyl-substituted aryl groups, resulting in optimized catalytic [2π + 2π] cycloaddition. The cyclopentyl groups provide a sufficiently open metal coordination sphere that encourages substrate coordination while remaining large enough to promote a challenging, turnover-limiting C(sp(3))-C(sp(3)) reductive elimination. PMID:26030841

  14. Learning Machine, Vietnamese Based Human-Computer Interface.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    The sixth session of IT@EDU98 consisted of seven papers on the topic of the learning machine--Vietnamese based human-computer interface, and was chaired by Phan Viet Hoang (Informatics College, Singapore). "Knowledge Based Approach for English Vietnamese Machine Translation" (Hoang Kiem, Dinh Dien) presents the knowledge base approach, which…

  15. Roof System EPDM Shrinkage.

    ERIC Educational Resources Information Center

    Betker, Edward

    1998-01-01

    Looks at Ethylene Propylene Diene Terpolymer rubber roof membranes and the potential problems associated with this material's shrinkage. Discusses how long such a roof should perform and issues affecting repair or replacement. Recommends that a building's function be considered in any roofing decision. (RJM)

  16. Total Synthesis of (±)-Gracilioether F.

    PubMed

    Shen, Xin-Yue; Peng, Xiao-Shui; Wong, Henry N C

    2016-03-01

    Total synthesis of (±)-gracilioether F was achieved via a pivotal reductive cleavage of 1,2-dioxane from allenic ester in 11 steps. The key 1,2-dioxane species, derived from singlet oxygen and a diene, could be used as a common precursor for a stereocontrolled formation of the crucial 1,4-diol through a reductive cleavage. PMID:26878903

  17. Enantioselective Synthesis of (+)-Estrone Exploiting a Hydrogen Bond-Promoted Diels−Alder Reaction

    PubMed Central

    2010-01-01

    Starting from Dane’s diene and methylcyclopentenedione, (+)-estrone is synthesized along the Quinkert−Dane route in 24% total yield. The key step is an enantioselective Diels−Alder reaction promoted by an amidinium catalyst as efficiently as by a traditional Ti-TADDOLate Lewis acid. PMID:20302330

  18. Continuous Flow of Nitroso Diels-Alder Reaction

    PubMed Central

    2015-01-01

    Our flow reaction systems have provided quantitative yields of nitroso Diels-Alder products with no byproducts in cases of cyclic dienes without temperature and pressure controls. Additionally, the reaction times were significantly shortened by using homogeneous catalyst (CuCl) or heterogeneous reagent (MnO2) in comparison with batch reaction. PMID:26138229

  19. Understanding Roofing Systems.

    ERIC Educational Resources Information Center

    Michelsen, Ted

    2001-01-01

    Reviews the various types of multi- and single-ply roofing commonly used today in educational facilities. Roofing types described involve built-up systems, modified bitumen systems; ethylene propylene diene terpolymer roofs; and roofs of thermoplastic, metal, and foam. A description of the Roofing Industry Educational Institute is included. (GR)

  20. Catalytic applications of mono- and dinuclear complexes containing metal-carbon sigma bonds. Final report, November 1, 1993--October 31, 1996

    SciTech Connect

    Norton, J.R.

    1996-12-31

    This report discusses results from several studies involved in the project. Investigations include: vibrational models for surface olefins and alkylidenes; mechanism of the formation and fragmentation of diosmacyclobutanes; reaction of dienes and allenes with diosmacyclobutanes; determination by nematic phase NMR of the structure of mononuclear and dinuclear ethylene complexes of osmium; and generation of ``coordinatively unsaturated`` complexes by protonation of methyl osmium complexes.

  1. Experimental and Computational Studies of the Macrocyclic Effect of an Auxiliary Ligand on Electron and Proton Transfers Within Ternary Copper(II)–Histidine Complexes

    SciTech Connect

    Song, Tao; Lam, Corey; Ng, Dominic C.; Orlova, G.; Laskin, Julia; Fang, De-Cai; Chu, Ivan K.

    2009-06-01

    The dissociation of [CuII(L)His]•2+ complexes [L = diethylenetriamine (dien) or 1,4,7-triazacyclononane (9-aneN3)] bears a strong resemblance to the previously reported behavior of [CuII(L)GGH]•2+ complexes. We have used low energy collision-induced dissociation experiments and density functional theory (DFT) calculations at the B3LYP/6-31+G(d) level to study the macrocyclic effect of the auxiliary ligands on the formation of His•+ from prototypical [CuII(L)His]•2+ systems. DFT revealed that the relative energy barriers of the same electron transfer (ET) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ are very similar, with the ET reactions of [CuII(9-aneN3)His]•2+ leading to the generation of two distinct His•+ species; in contrast, the proton transfer (PT) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ differ considerably. The PT reactions of [CuII(9-aneN3)His]•2+ are associated with substantially higher barriers (>13 kcal/mol) than those of [CuII(dien)His]•2+. Thus, the sterically encumbered auxiliary 9-aneN3 ligand facilitates ET reactions while moderating PT reactions, allowing the formation of hitherto non-observable histidine radical cations.

  2. Multistep Synthesis of a Terphenyl Derivative Showcasing the Diels-Alder Reaction

    ERIC Educational Resources Information Center

    Davie, Elizabeth A. Colby

    2015-01-01

    An adaptable multistep synthesis project designed for the culmination of a second-year organic chemistry laboratory course is described. The target compound is a terphenyl derivative that is an intermediate in the synthesis of compounds used in organic light-emitting devices. Students react a conjugated diene with dimethylacetylene dicarboxylate…

  3. Active low-valent niobium catalysts from NbCl5 and hydrosilanes for selective intermolecular cycloadditions.

    PubMed

    Satoh, Yasushi; Obora, Yasushi

    2011-10-21

    An active niobium catalyst was developed via a simple and nontoxic reduction method from NbCl(5)/hydrosilane and utilized for the selective [2 + 2 + 2] cycloaddition reaction of terminal alkynes and alkenes/α,ω-dienes, to give 1,3-cyclohexadiene derivatives in high yields with excellent chemo- and regioselectivity. PMID:21919436

  4. Catalyst-Controlled Formal [4 + 3] Cycloaddition Applied to the Total Synthesis of (+)-Barekoxide and (−)-Barekol

    PubMed Central

    Lian, Yajing; Miller, Laura C.; Born, Stephen

    2010-01-01

    The tandem cyclopropanation/Cope rearrangement between bicyclic dienes and siloxyvinyldiazoacetate, catalyzed by the dirhodium catalyst Rh2(R-PTAD)4 effectively accomplishes enantiodivergent [4 + 3] cycloadditions. The reaction proceeds by a cyclopropanation followed by a Cope rearrangement of the resulting divinylcyclopropane. This methodology was applied to the synthesis (+)-barekoxide (1) and (−)-barekol (2). PMID:20704267

  5. Design of a Brønsted acid with two different acidic sites: synthesis and application of aryl phosphinic acid-phosphoric acid as a Brønsted acid catalyst.

    PubMed

    Momiyama, N; Narumi, T; Terada, M

    2015-12-11

    A Brønsted acid with two different acidic sites, aryl phosphinic acid-phosphoric acid, has been synthesized. Its catalytic performance was assessed in the hetero-Diels-Alder reaction of aldehyde hydrates with Danishefsky's diene, achieving high reaction efficiency. PMID:26445921

  6. Chemical composition and antimicrobial activity of Cymbopogon citratus and Cymbopogon giganteus essential oils alone and in combination.

    PubMed

    Bassolé, I H N; Lamien-Meda, A; Bayala, B; Obame, L C; Ilboudo, A J; Franz, C; Novak, J; Nebié, R C; Dicko, M H

    2011-09-15

    As part of ongoing research on the chemical composition and the antimicrobial properties of Burkinabe plants essential oils alone and in combination, essential oils (EOs) from leaves of Cymbopogon citratus and Cymbopogon giganteus from Burkina Faso were analyzed by GC-FID and GC-MS. Five constituents, which accounted for 96.3% of the oil, were identified in the EO of C. citratus. Geranial (48.1%), neral (34.6%) and myrcene (11.0%) were the major constituents. For C. giganteus a total of eight compounds were identified which represented 86.0% of the oils extracted. The dominant compounds were limonene (42%) and a set of monoterpene alcohols: trans-p-mentha-1(7),8-dien-2-ol (14.2%), cis-p-mentha-1(7),8-dien-2-ol (12%), trans-p-mentha-2,8-dien-1-ol (5.6%) and cis-p-mentha-2,8-dien-1-ol (5.2%). The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose. PMID:21665450

  7. A new tetracyclic triterpene from the latex of Euphorbia nerifolia.

    PubMed

    Mallavadhani, Uppuluri V; Satyanarayana, K V S; Mahapatra, Anita; Sudhakar, A V S

    2004-02-01

    A new tetracyclic triterpene 9,19-cyclolanost-22(22'), 24-diene-3beta-ol, named as nerifoliene (2) along with euphol (1) were isolated from the fresh latex of Euphorbia nerifolia. Their structures were elucidated on the basis of spectral (IR, 1H and 13C NMR, FAB and EI Mass) data. PMID:14974615

  8. Antiparasitic, Nematicidal and Antifouling Constituents from Juniperus Berries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A bioassay-guided fractionation of Juniperus procera berries yielded antiparasitic, nematicidal and antifouling constituents, including a wide range of known abietane, pimarane and labdane diterpenes. Among these, abieta-7,13-diene (1) demonstrated in vitro antimalarial activity against Plasmodium f...

  9. Volatile non-terpenoid hydrocarbons from Ligusticum grayi roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The root essential oil of Ligusticum grayi Coult. & Rose (Apiaceae) contains three volatile non-terpenoid hydrocarbons: the known C11 compound viridene, whose structure is hereby corrected to 1-[(2Z)-pent-2-en-1-yl]cyclohexa-1,3-diene; and the heretofore unreported C10 compounds 1-[(2Z)-but-2-en-1-y...

  10. Study of Intermediate Products from the Cross-linking Reactions of Genipin with Beta-Lactoglobulin and Related Peptides by MALDI-TOF/TOF Mass Spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genipin, methyl-1R,2R,6S-2-hydroxy-9-(hydroxymethyl)-3-oxabicyclo[4.3.0]nona-4,8-diene-5-carboxylate, is an aglycone derivative from geniposide found in the Gardenia jasminoides fruits, obtained through enzymatic hydrolysis with beta-glucosidase. Genipin has been shown to be capable of cross-linking...

  11. Total Synthesis of a Diacetonide Derivative of Thuggacin A.

    PubMed

    Yadav, Jhillu S; Dutta, Palash

    2016-03-01

    A highly stereoselective total synthesis of the diacetonide derivative of the antibiotic thuggacin A has been described. The synthesis features the stereoselective Stille cross-coupling reaction to set up the whole carbon framework, aldol condensation to construct the highly substituted conjugated diene, non-Evans syn aldol, CBS reduction, Hantzsch's thiazole synthesis, Horner-Wadsworth-Emmons reaction, and Shiina's macrolactonization. PMID:26856208

  12. 21 CFR 522.1884 - Prednisolone sodium succinate injection.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Prednisolone sodium succinate injection. 522.1884... § 522.1884 Prednisolone sodium succinate injection. (a) Chemical name. 11 beta, 17, 21-Trihydroxypregna-1, 4-diene-3, 20-dione 21-succinate sodium salt. (b) Specifications. Each milliliter of...

  13. 21 CFR 522.1884 - Prednisolone sodium succinate injection.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Prednisolone sodium succinate injection. 522.1884... § 522.1884 Prednisolone sodium succinate injection. (a) Chemical name. 11 beta, 17, 21-Trihydroxypregna-1, 4-diene-3, 20-dione 21-succinate sodium salt. (b) Specifications. Each milliliter of...

  14. {sup 17}O NMR investigations of oxidative degradation in polymers

    SciTech Connect

    Alam, T.M.; Celina, M.; Assink, R.A.; Gillen, K.T.; Clough, R.L.

    1996-12-31

    We have initiated studies using both solution and solid state magic angle spinning {sup 17}O NMR for a series of oxidatively aged polymers. This short note reports the solution {sup 17}O NMR for oxidatively degraded polypropylene, ethylene-propylene-diene, polyisoprene, and nitrile rubber. Enriched O{sub 2} is used during the accelerated aging. 3 figs, 7 refs.

  15. A Selective Rh(I) -Catalyzed Substrate-Controlled C-C Bond Activation of Benzyl Sulfonamide/Alcohol-Tethered Alkylidenecyclopropanes.

    PubMed

    Chen, Kai; Liu, Jia-Xin; Tang, Xiang-Ying; Shi, Min

    2016-08-01

    Benzyl sulfonamide/alcohol-tethered alkylidenecyclopropanes undergo a rhodium-catalyzed and substrate-controlled selective C-C bond activation, producing three types of common organic structural units: benzo[c]azepine/oxepines, dihydronaphthalen-1-amines, and conjugated dienes. Epoxidation and aromatization of these products to construct two useful compounds have also been achieved. PMID:27305281

  16. Sesquiterpenoids from Valeriana tangutica.

    PubMed

    Qi, Huan-Yang; Wei, Xiao-Ning; Shi, Yan-Ping

    2009-01-01

    A new guaiane-type sesquiterpenoid ethoxyvalerianol (1) and one known sesquiterpenoid valeranone (2) together with selina-4,7(11)-diene (3) and selinene (4), which were obtained from (+)-maaliol (5) by decyclization and dehydration, were isolated from Valeriana tangutica. Their structures were elucidated by 1D- and 2D-NMR spectroscopic data and HR-ESI-MS analysis. PMID:19177234

  17. Dehydrogenative Diels-Alder reaction.

    PubMed

    Ozawa, Takuya; Kurahashi, Takuya; Matsubara, Seijiro

    2011-10-01

    The dehydrogenative cycloaddition of dieneynes, which possess a diene in the form of a styrene moiety and a dienophile in the form of an alkyne moiety, produces naphthalene derivatives when heated. It was found that a key requirement of this process is the presence of a silyl group attached to the alkyne moiety, which forces a dehydrogenation reaction to occur. PMID:21905638

  18. Soy protein with and without isoflavones fails to substantially increase postprandial antioxidant capacity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Five methods for the assessment of antioxidant capacity [whole plasma conjugated diene formation, low-density lipoprotein oxidation susceptibility, ferric-reducing ability of plasma, oxygen radical absorbance capacity and perchloric-acid-treated oxygen radical absorbance capacity (PCA-ORAC)] were us...

  19. Asymmetric synthesis of bicyclic dihydropyrans via organocatalytic inverse-electron-demand oxo-Diels-Alder reactions of enolizable aliphatic aldehydes.

    PubMed

    Li, Jun-Long; Yang, Kai-Chuan; Li, Yi; Li, Qiang; Zhu, Hong-Ping; Han, Bo; Peng, Cheng; Zhi, Yong-Gang; Gou, Xiao-Jun

    2016-08-23

    A highly enantioselective organocatalytic inverse-electron-demand oxo-Diels-Alder reaction involving aqueous acetaldehyde has been discovered. The reaction, in which cyclic enones serve as dienes in the presence of readily available secondary amine catalysts, allows facile construction of optically active bicyclic dihydropyrans. Other typical enolizable aliphatic aldehydes can also serve as competent dienophiles in the reaction. PMID:27436351

  20. Effect of almond skin polyphenolics and quercetin on human LDL and apolipoprotein B-100 oxidation and conformation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almond skin flavonoids (ASF) inhibit Cu2+-induced generation of conjugated dienes in low density lipoproteins (LDL). However, the effect of ASF on apolipoprotein B-100 oxidation and LDL conformation has not been explored. ASF (0.12-2.0 µmol/L gallic acid equivalents) were incubated with human LDL an...

  1. Hydrogen-Bonding Catalysis of Tetraalkylammonium Salts in an Aza-Diels-Alder Reaction.

    PubMed

    Kumatabara, Yusuke; Kaneko, Shiho; Nakata, Satoshi; Shirakawa, Seiji; Maruoka, Keiji

    2016-08-01

    A piperidine-derived tetraalkylammonium salt with a non-coordinating counteranion worked as an effective hydrogen-bonding catalyst in an aza-Diels-Alder reaction of imines and a Danishefsky diene. The hydrogen-bonding interaction between the ammonium salt and an imine was observed as part of a (1) H NMR titration study. PMID:27311924

  2. Organic Lecture Demonstrations.

    ERIC Educational Resources Information Center

    Silversmith, Ernest F.

    1988-01-01

    Provides a listing of 35 demonstrations designed to generate interest in organic chemistry and help put points across. Topics include opening lecture; molecular structure and properties; halogenation; nucleophilic substitution, alkenes and dienes, stereochemistry, spectroscopy, alcohols and phenols, aldehydes and ketones; carboxylic acids, amines,…

  3. Cytotoxic constituents of Lasiosphaera fenzlii on different cell lines and the synergistic effects with paclitaxel.

    PubMed

    Gao, J; Wang, L W; Zheng, H C; Damirin, A; Ma, C M

    2016-08-01

    The fruit body of Lasiosphaera fenzlii was found to show cytotoxicity on cancer cells during a preliminary screening. Repeated column chromatography of the fungal methanol extract resulted in the isolation of six compounds identified as 5α,8α-epidioxy-ergosta-6,22-dien-3β-ol (1), 5α,8α-epidioxy-ergosta-6,9(11),22-trien-3β-ol (2), 5α-ergosta-7,22-dien-3β-ol (3), 5α-ergosta-7,22-dien-3-one (4), ergosta-7,22-dien-3β,5α,6β-triol (5) and 6-dihydroxy-2,3-dihydro-1H-isoindol-1-one (6). The two peroxide compounds, 1 and 2, showed cytotoxic activity and compound 1 was selectively cytotoxic to cancer cells. Furthermore, compound 1 synergised the cytotoxicity of paclitaxel on Hela cells by increasing intracellular accumulation of paclitaxel in cancer cells but not in normal cells. PMID:26382563

  4. Mathematics Curriculum Guide, Section G.

    ERIC Educational Resources Information Center

    Victoria Education Dept. (Australia).

    This guide is a continuation of the series of guides starting with SE 012 723. The entire course is ungraded, but the material referred to in this guide would probably be covered in grade five or six. The concept of place value is studied more deeply using Dienes' Multiple Attribute Blocks, and used in the further development of formal algorithms.…

  5. Cyclopentadiene-mediated hydride transfer from rhodium complexes.

    PubMed

    Pitman, C L; Finster, O N L; Miller, A J M

    2016-07-12

    Attempts to generate a proposed rhodium hydride catalytic intermediate instead resulted in isolation of (Cp*H)Rh(bpy)Cl (1), a pentamethylcyclopentadiene complex, formed by C-H bond-forming reductive elimination from the fleeting rhodium hydride. The hydride transfer ability of diene 1 was explored through thermochemistry and hydride transfer reactions, including the reduction of NAD(+). PMID:26949917

  6. Ursane Triterpenoids from the Bark of Terminalia arjuna

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Five ursane type triterpene glucosyl esters including a new one, 2a,3ß-dihydroxyurs-12,18-dien-28-oic acid 28-O-ß-D-glucopyranosyl ester (1) were isolated from the bark of Terminalia arjuna, along with two known phenolic compounds. It is the first report of ursane type of triterpenoids from this spi...

  7. Attraction of a native Florida leafminer, Phyllocnistis insignis, to pheromone of an invasive citrus Leafminer, P. citrella.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We collected a native North American species, Phyllocnistis insignis (Frey & Boll) (Lepidoptera: Gracillariidae), in traps baited with a 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal (triene) and (Z,Z)-7,11-hexadecadienal (diene), 2 components of the sex pheromone of the invasive citrus leafminer, P....

  8. Attraction of a native Florida leafminer, Phyllocnistis insignis (Lepidoptera: Gracillariidae), to pheromone of invasive citrus leafminer, P. citrella: Evidence for mating disruption of a native nontarget species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We collected a native North American species, Phyllocnistis insignis (Frey & Boll), in traps baited with a 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal (triene) and (Z,Z)-7,11-hexadecadienal (diene), two components of the sex pheromone of the exotic citrus leafminer, Phyllocnistis citrella Stainton....

  9. Synthesis of cyclic sulfones by ring-closing metathesis.

    PubMed

    Yao, Qingwei

    2002-02-01

    A general and highly efficient synthesis of cyclic sulfones based on ring-closing metathesis has been developed. The synthetic utility of the resulting cyclic sulfones was demonstrated by their participation in stereoselective Diels-Alder reactions and transformation to cyclic dienes by the Ramberg-Bäcklund reaction. PMID:11820896

  10. Antimicrobial triterpenes from the stem bark of Crossopteryx febrifuga.

    PubMed

    Chouna, Jean Rodolphe; Tamokou, Jean-de-Dieu; Nkeng-Efouet-Alango, Pépin; Lenta, Bruno Ndjakou; Sewald, Norbert

    2015-07-01

    Phytochemical investigation of the stem bark extract of Crossopteryx febrifuga resulted in the isolation of epimeric mixtures of 3β-urs-12,20(30)-diene-27,28-dioic acid and 18-epi-3β-urs-12,20(30)-diene-27,28-dioic acid (1), as well as: 3β-D-glucopyranosylurs-12,20(30)-diene-27,28-dioic acid and 18-epi-3β-D-glucopyranosylurs-12,20(30)-diene-27,28-dioic acid (2), together with some known compounds such as the monoglyceride of palmitic acid, as well as β-sitosterol and its glucoside. The structures of the isolated compounds were determined by application of spectroscopic methods. The MeOH extract and compounds 1 and 2 were examined for antimicrobial activity in in vitro assays against bacteria (Enterobacter aerogenes ATCC13048, Escherichia coli ATCC8739, Klebsiella pneumoniae ATCC11296, Staphylococcus aureus) and fungi (Candida parapsilosis, Candida albicans ATCC 9002 and Cryptococcus neoformans IP 90526). The tested samples showed selective activities. The antibacterial and antifungal activities of compound 2 (MIC=8-64 μg/mL) were in some cases equal to or even higher than those of the respective reference drugs chloramphenicol (MIC=16- 64 μg/mL) and nystatin (MIC=128-256 μg/mL). PMID:26352201

  11. Optical Trajectories and the Informational Basis of Fly Ball Catching

    ERIC Educational Resources Information Center

    Marken, Richard S.

    2005-01-01

    D. M. Shaffer and M. K. McBeath (see record 2002-02027-006) plotted the optical trajectories of uncatchable fly balls and concluded that linear optical trajectory is the informational basis of the actions taken to catch these balls. P. McLeod, N. Reed, and Z. Dienes (see record 2002-11140-016) replotted these trajectories in terms of changes in…

  12. Antimicrobial effect of the Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (higher Basidiomycetes) and its main compounds.

    PubMed

    Vazirian, Mahdi; Faramarzi, Mohammad Ali; Ebrahimi, Seyed Esmaeil Sadat; Esfahani, Hamid Reza Monsef; Samadi, Nasrin; Hosseini, Seyed Aboulfazl; Asghari, Ali; Manayi, Azadeh; Mousazadeh, Ali; Asef, Mohammad Reza; Habibi, Emran; Amanzadeh, Yaghoub

    2014-01-01

    Mushrooms are considered one of the richest sources of natural antibiotics, and various species of them inhibit the growth of a wide diversity of microorganisms. Ganoderma lucidum, a well-known medicinal mushroom. has many pharmacological and biological activities including an antimicrobial effect, although few studies have investigated the antibacterial and antifungal effects of its purified compounds. The chemical structure of the purified compounds from the hexane fraction was elucidated as ergosta-7,22-dien-3β-yl acetate, ergosta-5,7,22-trien-3β-yl acetate (isopyrocalciferol acetate), ergosta-7,22-dien-3-one, ergosta-7,22-dien-3β-ol, and ergosta-5,7,22-trien-3β-ol (ergostrol). In addition, the structure of ganodermadiol was demonstrated after purification from the chloroform fraction. The fractions inhibited Gram-positive bacteria and yeast, with minimum inhibitory concentration values of 6.25 mg/mL, but were ineffective against Gram-negative bacteria in the tested concentrations. The results were comparable for isolated compounds, whereas the mixture of ergosta-7,22-dien-3β-yl acetate and isopyrocalciferol acetate was weakly effective against Escherichia coli (minimum inhibitory concentration, 10 mg/mL). It could be assumed that the antimicrobial effect of crude fractions is the consequence of mixing triterpenoid and steroid compounds. PMID:24940906

  13. Oil recovery process involving the injection of thickened water

    SciTech Connect

    Byham, D.E.; Chen, C.S.; Sheppard, E.W.

    1980-09-16

    Waterflood oil recovery process involving the use of an amphoteric polyelectrolyte as a thickening agent for mobility control. The amphoteric polyelectrolyte is a copolymer of a quaternary vinyl pyridinium sulfonate and a water-insoluble alpha olefin or hydrogenated diene. Specifically disclosed are vinyl pyridinium sulfonate-styrene block copolymers. The amphoteric polyelectrolytes are stable in high temperature and high brine environments.

  14. Spin labeling EPR studies of the properties of oxidized phospholipid-containing lipid vesicles.

    PubMed

    Megli, Francesco M; Russo, Luciana; Conte, Elena

    2009-02-01

    This study aims at characterizing the structure and some properties of phospholipid multi-lamellar vesicles (MLVs) containing the oxidized species gamma-palmitoyl-beta-(9-hydroperoxy-10,12-octadecanedienoyl)-lecithin (HPPLPC), gamma-palmitoyl-beta-(9-hydroxy-10,12-octadecanedienoyl)-lecithin (HOPLPC), gamma-palmitoyl-beta-glutaroyl-lecithin (GlPPC) and gamma-palmitoyl-beta-azelaoyl-lecithin (AzPPC). Sepharose 4B gel-chromatography was used to ensure and check that only MLVs are used in EPR measurements. Gel-solid to gel-liquid transition temperature (Tm), lateral phase separation, fluidity gradient and polarity profile were studied by use of EPR spectroscopy of enclosed n-doxylstearoyl lecithin spin labels. Contrarily to conjugate dienes and normal phospholipids, pure carboxyacyl species yielded aqueous suspensions showing gel-chromatography elution profile resembling that of lysolecithin micelles. Conjugate dienes/DPPC MLVs showed lateral phase separation at room temperature and Tm value lower than pure DPPC MLVs. Pure conjugate dienes MLVs resembled more PLPC MLVs and displayed free miscibility with PLPC in mixed MLVs. Pure HPPLPC MLV bilayer appeared to be slightly more rigid, while that of HOPLPC and the polarity profile of MLVs made of the pure conjugate dienes species were similar to those of normal PLPC. It is concluded that carboxyacyl lecithins in MLVs tend to disrupt vesicle structure, while conjugated dienes lecithins are more able to affect some physical properties of the bilayer, and that DPPC in MLVs enhances these effects while PLPC shows a better compatibility with the lipoperoxides. PMID:18996354

  15. Systemic complement activation, lung injury, and products of lipid peroxidation.

    PubMed Central

    Ward, P A; Till, G O; Hatherill, J R; Annesley, T M; Kunkel, R G

    1985-01-01

    Previously we have demonstrated that systemic activation of the complement system after intravenous injection of cobra venom factor (CVF) results in acute lung injury as reflected by increases in the vascular permeability of the lung as well as by morphologic evidence of damage to lung vascular endothelial cells. In using the vascular permeability of the lung as the reference, the current studies show a quantitative correlation between lung injury and the appearance in plasma of lipid peroxidation products (conjugated dienes) as well as increased concentrations of lactic dehydrogenase (LDH) and one of its isoenzymes (LDH-4). After injection of CVF, extracts of lungs also showed elevated levels of conjugated dienes, whereas no elevations were found in extracts of liver, kidney, and spleen. There was no evidence in CVF-injected rats of renal or hepatic injury as reflected by the lack of development of proteinuria and the failure to detect increased serum levels of liver-related enzymes. Other peroxidation products identified in plasma of CVF-injected rats involved hydroperoxides and fluorescent compounds with features of Schiff bases. Not surprisingly, malondialdehyde was not found to be a reliable plasma indicator of lipid peroxidation associated with oxygen radical-mediated lung vascular injury. In using a model of oxygen radical-independent lung injury induced by oleic acid, although large amounts of LDH and LDH-4 were found in the plasma, no increases in plasma levels of conjugated dienes were detected. In CVF-injected animals treated with interventions protective against lung injury (neutrophil depletion, catalase, hydroxyl radical scavengers, or iron chelators), there were striking reductions in the plasma levels of conjugated dienes, hydroperoxides, and fluorochromic products. Morphometric analysis of lung sections revealed that the protective interventions did not interfere with the accumulation of neutrophils in lung interstitial capillaries after systemic

  16. An unusual lanostane-type triterpenoid, spiroinonotsuoxodiol, and other triterpenoids from Inonotus obliquus.

    PubMed

    Handa, Noriko; Yamada, Takeshi; Tanaka, Reiko

    2010-10-01

    An unusual lanostane-type triterpenoid, spiroinonotsuoxodiol (1), and two lanostane-type triterpenoids, inonotsudiol A (2) and inonotsuoxodiol A (3), were isolated from the sclerotia of Inonotus obliquus. Their structures were determined to be (3S,7S,9R)-3,7-dihydroxy-7(8-->9)abeo-lanost-24-en-8-one (1), lanosta-8,24-dien-3beta,11beta-diol (2), and (22R)-3beta,22-dihydroxylanosta-8,24-dien-11-one (3) on the basis of NMR spectroscopy, including 1D and 2D ((1)H-(1)H COSY, NOESY, HMQC, HMBC) NMR, and FABMS. Compounds 1-3 showed moderate activity against cultured P388, L1210, HL-60 and KB cells. PMID:20691456

  17. New Antiplasmodial Diterpenes from Gutierrezia sarothrae.

    PubMed

    Su, Qingxi; Dalal, Seema; Goetz, Michael; Cassera, Maria B; Kingston, David G I

    2016-06-01

    Bioassay guided fractionation of the MeOH extract of the plant Gutierrezia sarothrae (Asteraceae) using an assay for antiplasmodial activity against the drug-resistant Dd2 strain of Plasmodium falciparum led to the isolation of the two new diterpenes 3α-angeloyloxy-15-hydroxylabda-7,13-dien-16,15-olid-18-oic acid (1) and 3α-angeloyloxy-15-methoxylabda-7,13-dien-16,15-olid-18-oic acid (2). The structures of 1 and 2 were elucidated by interpretation of 1D and 2D NMR spectroscopic data, mass spectrometry, and comparison with the data of related compounds reported in the literature. Compound 1 exhibited moderate antiplasmodial activity with an IC50 values of 10.4 ± 4.3 μM. PMID:27534100

  18. Complexes of ruthenium and rhodium with aliphatic amines in the catalysis of hydrogenation of unsaturated hydrocarbons

    SciTech Connect

    Turisbekova, K.K.; Shuikina, L.P.; Parenago, O.P.; Frolov, V.F.

    1989-02-01

    The authors synthesized new catalysts highly active in the hydrogenations of unsaturated hydrocarbons, based on complexes of ruthenium and rhodium with higher aliphatic amines, which are soluble in aromatic solvents. The complexes acquired catalytic activity in hydrogenation as a result of their treatment with diisobutyl aluminum hydride. Olefins (1-hexene, cyclopentene, cyclohexene) or dienes (isoprene) were used as the unsaturated compounds. For the ruthenium based catalysts, the highest activity was observed during the hydrogenation of 1-hexene. For the rhodium-based catalysts, the activity in the hydrogenation of olefins and dienes was approximately the same. In the case of the rhodium complex catalysts, the hydrogenation of 1-hexene was accompanied by a side-reaction consisting in isomerization into olefins with inner double bonds.

  19. Trinorcucurbitane and cucurbitane triterpenoids from the roots of Momordica charantia.

    PubMed

    Chen, Jianchao; Tian, Renrong; Qiu, Minghua; Lu, Lu; Zheng, Yongtang; Zhang, Zhongquan

    2008-02-01

    Five cucurbitacins, kuguacins A-E (1-5), together with three known analogues, 3beta,7beta,25-trihydroxycucurbita-5,(23E)-diene-19-al (6), 3beta,25-dihydroxy-5beta,19-epoxycucurbita-6,(23E)-diene (7), and momordicine I (8), were isolated from roots of Momordica charantia. Structures of 1-5 were elucidated by NMR and MS spectroscopic analysis. Among them, compounds 3-5 possess an unprecedented 25,26,27-trinorcucurbitane backbone. Compounds 3 and 5 showed moderate anti-HIV-1 activity with EC(50) values of 8.45 and 25.62 microg/ml, and exerted minimal cytotoxicity against C8166 cells (IC(50)>200 microg/ml), with a selectivity index more than 23.68 and 7.81, respectively. PMID:18045630

  20. Structural elucidation of two new megastigmane glycosides from the leaves of Aquilaria sinensis.

    PubMed

    Sun, Jian; Xia, Fang; Wang, Shu; Wang, Ke-Yuan; Chen, Jin-Ming; Tu, Peng-Fei

    2015-04-01

    The present study was designed to determine the chemical constituents and identify new components of the leaves of Aquilaria sinensis (Lour.) Gilg. The compounds were isolated and purified by repeated silica gel, Sephadex LH-20, and ODS column chromatography and their structures were elucidated by NMR and HR-ESI-MS spectrometry. Eight megastigmane glycosides and two cucurbitacins were isolated and identified as (9S) megastigma-4,7-diene-2,3,9-triol 9-O-β-D-glucopyranoside (1), (9S) megastigma-4(13),7-diene-3,6,9-triol 9-O-β-D-glucopyranoside (2), macarangloside D (3), corchoionoside C (4), staphylionoside H (5), (+) 3-oxo-α-ionol-β-D-glucopyranoside (6), (-) 3-oxo-α-ionol-β-D-glucopyranoside (7), citroside B (8), 2-O-β-D-glucopyranosyl cucurbitacin I (9), bryoamaride (10). Compounds 1 and 2 were newly identified megstigmane glucosides and reported from this genus for the first time. PMID:25908626

  1. New triterpene glucosides from the roots of Rosa laevigata Michx.

    PubMed

    Yuan, Jing-Quan; Yang, Xin-Zhou; Miao, Jian-Hua; Tang, Chun-Ping; Ke, Chang-Qiang; Zhang, Ji-Bao; Ma, Xiao-Jun; Ye, Yang

    2008-01-01

    Two new ursane-type triterpene glucosides, 2alpha,3alpha,24-trihydroxyurs-12,18-dien-28-oic acid beta-D-glucopyranosyl ester (1) and 2alpha,3alpha,23-trihydroxyurs-12,19(29)-dien-28-oic acid beta-D-glucopyranosyl ester (2), were isolated from the roots of Rosa laevigata, together with three known compounds: 2alpha,3beta,19alpha-trihydroxyurs-12-en-28-oic acid beta-Dglucopyranosyl ester (3), 2alpha,3alpha,19alpha-trihydroxyurs-12-en-28-oic acid beta-D-glucopyranosyl ester (4) and 2alpha,3beta,19alpha,23-tetrahydroxyurs-12-en-28-oic acid beta-D-glucopyranosyl ester (5). The structures of new compounds were established on the basis of detailed 1D and 2D NMR spectroscopic analyses. Compounds 2 and 5 exhibited modest in vitro antifungal activities against Candida albicans and C. krusei. PMID:18830152

  2. Sex-pairing pheromone in the Asian termite pest species Odontotermes formosanus.

    PubMed

    Wen, Ping; Ji, Bao-Zhong; Liu, Shu-Wen; Liu, Cong; Sillam-Dussès, David

    2012-05-01

    The sex-pairing pheromone of the black winged subterranean termite, Odontotermes formosanus (Shiraki) (Isoptera, Termitidae), was investigated using headspace-SPME, GC-MS, GC-EAD, and attraction bioassays. Females secrete the pheromone from their sternal gland to attract males. The sex-pairing pheromone is composed of (Z,Z)-dodeca-3,6-dien-1-ol and (Z)-dodec-3-en-1-ol, estimated at 9 to 16.64 ng and 0.2 to 0.54 ng, respectively. Both short- and long-distance sex attraction bioassays were employed to show that these compounds act in synergy at long distance, but only (Z,Z)-dodeca-3,6-dien-1-ol is active at short distance. The pheromone may be useful in efforts to control this pest, which is considered one of the most harmful termite species in Southeast Asia. PMID:22527053

  3. Photochemical transformations of cis-1,2-dibenzoylalkenes

    SciTech Connect

    Lahiri, S.; Dabral, V.; Chauhan, S.M.S.; Chakachery, E.; Kumar, C.V.; Scaiano, J.C.; George, M.V.

    1980-01-01

    Photorearrangements of cis-1,2-dibenzoylalkenes such as 2,3-dibenzoylbicyclo(2.2.2)octa-2,5-diene (9), 2.3-dibenzoylbicyclo(2.2.2)oct-2-ene (21), 2,3-dibenzoylbicyclo(2.2.1)hept-2-ene (28), and 2,3-dibenzoylbicyclo-(2.2.1)hepta-2,5-diene (35) are reported. Irradiation of 9 in methanol gives a mixture of isomeric esters 13 (69%) and 14 (1%), whereas in benzene a mixture of carboxylic acids 10 (26%) and 11 (6%) and loctone 12 (23%) is formed. Similar rearrangements have been observed in the case of 21 and 28. Irradiation of 35 in benzene, however, gives mostly the quadricyclane 36. Laser flash-photolysis studies have shown that diradical intermediates such as 18 and 19 may be involved in the transformation of 9 to the different products. Similar diradical intermediates have been postulated in the rearrangements of 21 and 28.

  4. Gold(I)-Catalyzed Generation of the Two Components of a Formal [4+2] Cycloaddition Reaction for the Synthesis of Tetracyclic Pyrano[2,3,4-de]chromenes.

    PubMed

    Arto, Tamara; Fañanás, Francisco J; Rodríguez, Félix

    2016-06-13

    Ortho-Alkynylbenzaldehydes have been widely used to generate isochromenylium derivatives through gold-catalyzed cycloisomerization. These isochromenylium derivatives have been exploited as formal diene derivatives for reactions with different dienophiles. Herein, we describe the behavior of ortho-alkynylsalicylaldehydes, a particular case of ortho-alkynylbenzaldehydes. The gold-catalyzed cycloisomerization of ortho-alkynylsalicylaldehydes delivers an unusual heterodiene derivative that reacts with electron-rich alkenes through a formal [4+2] cycloaddition. In this reaction, both the diene and dienophile are generated in situ through gold-catalyzed cycloisomerization of appropriate alkynamines or alkynols. This reaction was used to synthesize complex tetracyclic pyrano[2,3,4-de]chromenes from two very simple starting materials (an ortho-alkynylsalicylaldehyde and an alkynamine or alkynol) with complete atom economy and with selective formation of bonds, cycles, and stereocenters. PMID:27167506

  5. Biotransformation of 6-dehydroprogesterone with Aspergillus niger and Gibberella fujikuroi.

    PubMed

    Ahmad, Malik Shoaib; Zafar, Salman; Yousuf, Sammar; Wahab, Atia-Tul-; Rahman, Atta-Ur-; Choudhary, M Iqbal

    2016-08-01

    Microbial transformation of 6-dehydroprogesterone (1) with Aspergillus niger yielded three new metabolites, including 6β-chloro-7α,11α-dihydroxypregna-4-ene-3,20-dione (2), 7α-chloro-6β,11α-dihydroxypregna-4-ene-3,20-dione (3), and 6α,7α-epoxy-11α-hydroxypregna-4-ene-3,20-dione (4), and two known metabolites; 6α,7α-epoxypregna-4-ene-3,20-dione (5), and 11α-hydroxypregna-4,6-diene-3,20-dione (6). Compounds 2, and 3 contain chlorohydrin moiety at C-6, and C-7, respectively. The biotransformation of 1 with Gibberella fujikuroi yielded a known compound, 11α,17β-dihydroxyandrosta-4,6-dien-3-one (7). PMID:27133903

  6. Chemical constituents from the fruiting bodies of Cryptoporus volvatus.

    PubMed

    Wang, Junchi; Li, Guangzhi; Lv, Na; Gao, Li; Cao, Li; Shen, Liangang; Si, Jianyong

    2016-06-01

    New drimane-type sesquiterpene cryptoporol A (1), cryptoporic acid derivative 6'-cryptoporic acid E methyl ester (2), and pseudouridine derivative cryptoporine A (3), as well as a known ergosterol 5α,8α-epidioxy-22E-ergosta-6,22-dien-3β-ol (4), were isolated from a 90 % alcohol extract of the fruiting bodies of Cryptoporus volvatus. The structures of these compounds were established by spectroscopic analysis and circular dichroism. 5α,8α-epidioxy-22E-ergosta-6,22-dien-3β-ol (4) exhibited antiviral activity against porcine reproductive and respiratory syndrome virus, and all compounds showed weak antioxidant activities. PMID:27146415

  7. Ultrasonic Synthesis, Molecular Structure and Mechanistic Study of 1,3-Dipolar Cycloaddition Reaction of 1-Alkynylpyridinium-3-olate and Acetylene Derivatives.

    PubMed

    Aboelnaga, Asmaa; Hagar, Mohamed; Soliman, Saied M

    2016-01-01

    Regioselectively, ethyl propiolate reacted with 1-(propergyl)-pyridinium-3-olate to give two regioisomers; ethyl 4-oxo-8-(prop-2-ynyl)-8-aza-bicyclo(3.2.1)octa-2,6-diene-6-carboxylate 4, ethyl 2-oxo-8-(prop-2-ynyl)-8-aza-bicyclo(3.2.1)octa-3,6-diene-6-carboxylate 5 as well as ethyl 2,6-dihydro-6-(prop-2-ynyl)furo(2,3-c)pyridine-3-carboxylate 6. The obtained compounds were identified by their spectral (IR, mass and NMR) data. Moreover, DFT quantum chemical calculations were used to study the mechanism of the cycloaddition reaction. The regioselectivity was explained using transition state calculations, where the calculations agreed with the formation of products 4 and 5 in almost the same ratio. The reaction was also extended for diphenylaceylene as dipolarophile to give only two products instead of three. PMID:27367661

  8. Biomimetic Nitration of Conjugated Linoleic Acid: Formation and Characterization of Naturally Occurring Conjugated Nitrodienes

    PubMed Central

    Woodcock, Steven R.; Salvatore, Sonia R.; Bonacci, Gustavo; Schopfer, Francisco J.; Freeman, Bruce A.

    2014-01-01

    Nitro-conjugated linoleic acids (NO2-cLA), endogenous nitrodiene lipids which act as inflammatory signaling mediators, were isolated and single isomers purified from the biomimetic acidic nitration products of conjugated linoleic acid (CLA). Structures were elucidated by means of detailed NMR and HPLC–MS/MS spectroscopic analysis and the relative double bond configurations assigned. Additional synthetic methods produced useful quantities and similar isomeric distributions of these unusual and reactive compounds for biological studies and isotopic standards, and the potential conversion of nitro-linoleic to nitro-conjugated linoleic acids was explored via a facile base-catalyzed isomerization. This represents one of the few descriptions of naturally occurring conjugated nitro dienes (in particular, 1-nitro 1,3-diene), an unusual and highly reactive motif with few biological examples extant. PMID:24350701

  9. Female Iberian wall lizards prefer male scents that signal a better cell-mediated immune response.

    PubMed

    López, Pilar; Martín, José

    2005-12-22

    In spite of the importance of chemoreception in sexual selection of lizards, only a few studies have examined the composition of chemical signals, and it is unknown whether and how chemicals provide honest information. Chemical signals might be honest if there were a trade-off between sexual advertisement and the immune system. Here, we show that proportions of cholesta-5,7-dien-3-ol in femoral secretions of male Iberian wall lizards (Podarcis hispanica) were related to their T-cell-mediated immune response. Thus, only males with a good immune system may allocate higher amounts of this chemical to signalling. Furthermore, females selected scents of males with higher proportions of cholesta-5,7-dien-3-ol and lower proportions of cholesterol. Thus, females might base their mate choice on the males' quality as indicated by the composition of their chemical signals. PMID:17148218

  10. Acid-catalyzed Furfuryl Alcohol Polymerization: Characterizations of Molecular Structure and Thermodynamic Properties

    SciTech Connect

    Kim, Taejin; Assary, Rajeev A.; Marshall, Christopher L.; Gosztola, David J.; Curtiss, Larry A.; Stair, Peter C.

    2011-07-22

    The liquid-phase polymerization of furfuryl alcohol catalyzed by sulfuric acid catalysts and the identities of molecular intermediates were investigated by using Raman spectroscopy and density functional theory calculation. At room temperature, with an acid catalyst, a vigorous furfuryl alcohol polymerization reaction was observed, whereas even at a high water concentration, furfuryl alcohol was very stable in the absence of an acid catalyst. Theoretical studies were carried out to investigate the thermodynamics of protonation of furfuryl alcohol, initiation of polymerization, and formation of conjugated dienes and diketonic species by using the B3LYP level of theory. A strong aliphatic C=C band observed in the calculated and measured Raman spectra provided crucial evidence to understand the polymerization reaction mechanism. It is confirmed that the formation of a conjugated diene structure rather than a diketone structure is involved in the furfuryl alcohol polymerization reaction.

  11. Acid-catalyzed furfurly alcohol polymerization : characterizations of molecular structure and thermodynamic properties.

    SciTech Connect

    Kim, T.; Assary, R. S.; Marshall, C. L.; Gosztola, D. J.; Curtiss, L. A.; Stair, P. C.

    2011-01-01

    The liquid-phase polymerization of furfuryl alcohol catalyzed by sulfuric acid catalysts and the identities of molecular intermediates were investigated by using Raman spectroscopy and density functional theory calculation. At room temperature, with an acid catalyst, a vigorous furfuryl alcohol polymerization reaction was observed, whereas even at a high water concentration, furfuryl alcohol was very stable in the absence of an acid catalyst. Theoretical studies were carried out to investigate the thermodynamics of protonation of furfuryl alcohol, initiation of polymerization, and formation of conjugated dienes and diketonic species by using the B3LYP level of theory. A strong aliphatic C=C band observed in the calculated and measured Raman spectra provided crucial evidence to understand the polymerization reaction mechanism. It is confirmed that the formation of a conjugated diene structure rather than a diketone structure is involved in the furfuryl alcohol polymerization reaction.

  12. Two unusual naphthalene-containing compounds from a freshwater fungus YMF 1.01029.

    PubMed

    Dong, Jin-Yan; Song, Hong-Chuan; Li, Jian-Hua; Wang, Chun-Ren; Sun, Rong; Tang, Yu-Shu; Shen, Kai-Ze; Wang, Le; Wang, Li-Mei; Zhou, Yong-Ping; Li, Lei; Zhang, Ke-Qin

    2009-04-01

    Two novel naphthalene-containing compounds, colelomycerones A and B (1 and 2, resp.), and three known metabolites, including preussomerin D (3), (2RS,2'SR,3'E,3SR,4E,8E)-1-O-(beta-D-glucopyranosyl)-3-hydroxy-2-[(2-hydroxyoctadec-3-enoyl)amino]-9-methyloctadeca-4,8-diene (4), and 3beta-hydroxy-5alpha,8alpha-epidioxyergosta-6,22-diene (5), were isolated from the culture broth of an unidentified freshwater water fungus YMF 1.01029. This fungus was collected from a decaying branch of an unidentified tree near Lake Fuxian in Yunnan Province, China. The structures of these five compounds were determined on the basis of their spectroscopic and mass-spectrometric data. Colelomycerones A and B (1 and 2, resp.) represent unprecendented examples of naphthalene-1,2-diones with novel cyclic acetals. Compounds 1-3 showed noticeable antifungal and antibacterial activities. PMID:19353541

  13. Idling revolution control device for internal combustion engine

    SciTech Connect

    Sasaki, T.

    1988-12-13

    This patent describes a method of manufacturing a peroxide curable synthetic elastomer with improved chemical aging and oil resistance properties, comprising the steps of: reacting ethylene, propylene and a diene monomer in a solvent solution in the presence of a suitable catalyst; forming a water slurry product of the resulting ethylene-propylene-nonconjugated diene monomer terpolymer; and solution blending a liquid, high vinyl 1,2-polybutadiene resin with the terpolymer product by adding the 1,2-polybutadiene to the slurry prior to separating and during the terpolymer elastomer, the 1,2-polybutadiene having at least about 80 mole % 1,2 vinyl structure with a pendant vinyl group for every other chain carbon.

  14. Aromatization of hydrocarbons by oxidative dehydrogenation catalyzed by the mixed addenda heteropoly acid H sub 5 PMo sub 10 V sub 2 O sub 40

    SciTech Connect

    Neumann, R. ); Lissle, M. )

    1989-09-15

    The mixed addenda heteropoly acid H{sub 5}PMo{sub 10}V{sub 2}O{sub 40} dissolved in 1,2-dichloroethane with tetraglyme, forming the (tetraglyme){sub 3}-H{sub 5}PMo{sub 10}V{sub 2}O{sub 40} complex, catalyzes the aromatization of cyclic dienes at moderate temperatures in the presence of molecular oxygen. Dehydrogenations of exocyclic dienes such as limonene show that dehydrogenation is preceded by isomerization to their endocyclic isomers. Aromatization takes place by successive one-electron transfers and proton abstractions from the organic substrate to the heteropoly acid the latter being reoxidized by dioxygen coupled with the formation of water.

  15. Influence of stage of lactation on the triacylglycerol composition of buffalo milk fat.

    PubMed

    Arumughan, C; Narayanan, K M

    1981-03-01

    Milk fats obtained from colostrum and early, middle and late lactation samples of buffalo milk were analyzed for their triacylglycerol (TG) compositions. Each milk fat was first separated by thin layer chromatography (TLC) into high, medium and low molecular weight TG. The TG fractions thus obtained were further segregated by argentation TLC, according to their degree of unsaturation into saturated, trans-monoene, cis-monoene, diene and polyene species. With progressive lactation, the major changes from colostral fat were an increase in lower fatty acids and decline in oleic acid. This caused, in turn, marked variations in saturated TG and diene TG and, to a smaller extent, in polyene TG. Monoene TG, both cis and trans, remained practically constant throughout. These trends were largely reversed toward the end of lactation. PMID:7219086

  16. A new sesquiterpenoid from Polyalthia petelotii.

    PubMed

    Yang, Caiqiong; Peng, Wei; Yang, Bijuan; Zhang, Junjie; Chen, Yegao

    2016-07-01

    A new sesquiterpenoid (‒)-ethyl dihydrophaseate (1) was isolated from the stems and leaves of Polyalthia petelotii, together with two clerodane diterpenoids, 16α-hydroxycleroda-3,13(14)Z-dien-15,16-olide (2), 15-hydroxy-cis-ent-cleroda-3,13(E)-diene (3), a eudesmane sesquiterpenoid, eudesm-4(15)-ene-7α,11-diol (4), an aromatic aldehyde, vanillin (5), a bisisoquinolines alkaloid, spinosine (6) and an aporphine alkaloid, (‒)-oliveroline-β-N-oxide (7). Their structures were established by extensive spectroscopic analysis, including 2D-NMR techniques. Compounds 3, 4 and 6 were isolated from the genus Polyalthia for the first time and the others obtained originally from P. petelotii. The isolates were assessed for their cytotoxicity against five human tumour lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), and the result showed that only 2 displayed weak inhibitory activity. PMID:26666779

  17. Synthesis, characterization and fluorescence studies of novel bi-phenyl based acrylate and methacrylate

    NASA Astrophysics Data System (ADS)

    Baskar, R.; Subramanian, K.

    2011-09-01

    4-[(1 E)-3-(biphenyl-4-yl)buta-1,3-dien-1-yl]phenyl prop-2-enoate ( ACH) and 4-[(1 E)-3-(biphenyl-4-yl)buta-1,3-dien-1-yl]phenyl 2-methylprop-2-enoate ( MCH) was synthesized from biphenyl in three steps and their structures were confirmed by elemental analysis, IR, NMR ( 1H, 13C, DEPT135, 1H- 1H COSY, 1H- 13C HSQC and 1H- 13C HMBC) spectroscopic techniques. In this present study, various physicochemical characteristics we demonstrate solubility, color, absorbance and fluorescence property of novel biphenyl based acrylate and methacrylate measured in different solvents like benzene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylsulfoxide and ethanol.

  18. Mechanistic Characterisation of Two Sesquiterpene Cyclases from the Plant Pathogenic Fungus Fusarium fujikuroi.

    PubMed

    Burkhardt, Immo; Siemon, Thomas; Henrot, Matthias; Studt, Lena; Rösler, Sarah; Tudzynski, Bettina; Christmann, Mathias; Dickschat, Jeroen S

    2016-07-18

    Two sesquiterpene cyclases from Fusarium fujikuroi were expressed in Escherichia coli and purified. The first enzyme was inactive because of a critical mutation, but activity was restored by sequence correction through site-directed mutagenesis. The mutated enzyme and two naturally functional homologues from other fusaria converted farnesyl diphosphate into guaia-6,10(14)-diene. The second enzyme produced eremophilene. The absolute configuration of guaia-6,10(14)-diene was elucidated by enantioselective synthesis, while that of eremophilene was evident from the sign of its optical rotation and is opposite to that in plants but the same as in Sorangium cellulosum. The mechanisms of both terpene cyclases were studied with various (13) C- and (2) H-labelled FPP isotopomers. PMID:27294564

  19. General Route to Cyclobutadiene Rhodium Complexes.

    PubMed

    Perekalin, Dmitry S; Shvydkiy, Nikita V; Nelyubina, Yulia V; Kudinov, Alexander R

    2015-11-01

    Cyclobutadiene rhodium complexes bear high potential for applications in organometallic synthesis and catalysis. We have found that the cyclobutadiene complexes with substitutionally labile p-xylene ligands [(C4 R4 )Rh(p-xylene)](+) can be synthesized in one step from the commercially available bis(ethylene) complex [{(C2 H4 )2 RhCl}2 ], p-xylene, and internal alkynes. The replacement of p-xylene by various ligands provides a general access to other [(C4 R4 )Rh] compounds, such as [(C4 R4 )RhCl]x , [(C4 R4 )RhL3 ](+) , [(C4 R4 )Rh(C5 H5 )], and [(C4 R4 )Rh(arene)](+) . Complex [(C4 Et4 )Rh(p-xylene)](+) also catalyzes an unusual cycloisomerization of a 1,11-dien-6-yne into a bicyclic diene. PMID:26387565

  20. Palladium-Catalyzed Trimethylenemethane Cycloaddition of Olefins Activated by the σ-Electron-Withdrawing Trifluoromethyl Group.

    PubMed

    Trost, Barry M; Debien, Laurent

    2015-09-16

    α-Trifluoromethyl-styrenes, trifluoromethyl-enynes, and dienes undergo palladium-catalyzed trimethylenemethane cycloadditions under mild reaction conditions. The trifluoromethyl group serves as a unique σ-electron-withdrawing group for the activation of the olefin toward the cycloaddition. This method allows for the formation of exomethylene cyclopentanes bearing a quaternary center substituted by the trifluoromethyl group, compounds of interest for the pharmaceutical, agrochemical, and materials industries. In the diene series, the cycloaddition operates in a [3 + 4] and/or [3 + 2] manner to give rise to seven- and/or five-membered rings. This transformation greatly improves the scope of the TMM cycloaddition technology and provides invaluable insights into the reaction mechanism. PMID:26291872

  1. Catalytic effect of gallium chloride in the diels-alder reaction between maleic anhydride and its derivatives and unsubstituted and substituted anthracenes

    SciTech Connect

    Kiselev, V.D.; Konovalov, A.I.; Shakirov, I.M.

    1985-11-10

    The stability of n, v complexes between gallium chloride and unsubstituted and substituted maleic anhydrides was determined in benzene by a thermochemical method; it was shown that the stability of the complexes decreases in the transition from maleic anhydrides with electron-donating substituents to maleic anhydrides with electron-withdrawing substituents. The reactivity of these dienophiles in the uncatalyzed Diels-Alder reactions with unsubstituted and substituted anthracenes in benzene and in the reactions catalyzed by gallium chloride was studied. The reactivity of the dienophiles varies similarly in the reactions with the investigated dienes, and this rules out treatment of steric hindrances as the reason for the reduced reactivity of the substituted dienophiles. A decrease in the catalytic effect was observed for the unreactive diene-dienophile pairs.

  2. A chicory cytochrome P450 mono-oxygenase CYP71AV8 for the oxidation of (+)-valencene.

    PubMed

    Cankar, Katarina; van Houwelingen, Adèle; Bosch, Dirk; Sonke, Theo; Bouwmeester, Harro; Beekwilder, Jules

    2011-01-01

    Chicory (Cichorium intybus L.), which is known to have a variety of terpene-hydroxylating activities, was screened for a P450 mono-oxygenase to convert (+)-valencene to (+)-nootkatone. A novel P450 cDNA was identified in a chicory root EST library. Co-expression of the enzyme with a valencene synthase in yeast, led to formation of trans-nootkatol, cis-nootkatol and (+)-nootkatone. The novel enzyme was also found to catalyse a three step conversion of germacrene A to germacra-1(10),4,11(13)-trien-12-oic acid, indicating its involvement in chicory sesquiterpene lactone biosynthesis. Likewise, amorpha-4,11-diene was converted to artemisinic acid. Surprisingly, the chicory P450 has a different regio-specificity on (+)-valencene compared to germacrene A and amorpha-4,11-diene. PMID:21115006

  3. Biodegradation of nitrobenzene through a hybrid pathway in Pseudomonas putida

    SciTech Connect

    Jung, K.H.; Lee, J.Y.; Kim, H.S.

    1995-12-20

    The biodegradation of nitrobenzene was attempted by using Pseudomonas putida TB 103 which possesses the hybrid pathway combining the tod and the tol pathways. Analysis of the metabolic flux of nitrobenzene through the hybrid pathway indicated that nitrobenzene was initially oxidized to cis-1,2-dihydroxy-3-nitrocyclohexa-3,5-diene by toluene dioxygenase in the tod pathway and then channeled into the tol pathway, leading to the complete biodegradation of nitrobenzene. A crucial metabolic step redirecting the metabolic flux of nitrobenzene from the tod to the tol pathway was determined from the genetic and biochemical studies on the enzymes involved in the tol pathway. From these results, it was found that toluate-cis-glycol dehydrogenase could convert cis-1,2-dihydroxy-3-nitrocyclohexa-3,5-diene to catechol in the presence of NAD{sup +} with liberation of nitrite and the reduced form of NAD{sup +} (NADH) into the medium.

  4. Four new glycosides from the fruit of Xanthium sibiricum Patr.

    PubMed

    Jiang, Hai; Yang, Liu; Liu, Chang; Hou, Hui; Wang, Qiuhong; Wang, Zhibin; Yang, Bingyou; Kuang, Haixue

    2013-01-01

    Four new glycosides, namely 3β-norpinan-2-one 3-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (1), (6Z)-3-hydroxymethyl-7-methylocta-1,6-dien-3-ol 8-O-β-d-glucopyranoside (2), (6E)-3-hydroxymethyl-7-methylocta-1,6-dien-3-ol 8-O-β-d-gluco-pyranoside (3), and 7-[(β-d-apiofuranosyl-(1→6)-β-d-glucopyranosyl)oxymethy]-8,8-dimethyl-4,8-dihydrobenzo[1,4]thiazine-3,5-dione (4), were isolated from the fruits of Xanthium sibiricum Patr together with three known compounds, xanthiside (5), adenosine (6), and 2,3-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)-propan-1-one (7). The structures of the new compounds were determined on the basis of detailed spectroscopic analyses. PMID:24152669

  5. New kaurene diterpenoid glycosides from fenugreek seeds.

    PubMed

    Pang, Xu; Kang, Li-Ping; Yu, He-Shui; Zhao, Yang; Xiong, Cheng-Qi; Zhang, Jie; Ma, Bai-Ping

    2013-01-01

    Two new kaurene diterpenoid glycosides, named Graecumoside A (1) and B (2), were isolated from fenugreek seeds, along with three known flavonoid-C-glycosides, isoorientin (3), isovitexin (4) and vitexin (5). By combined analyses of 1D- and 2D-NMR, and MS spectroscopy, the structures of two new compounds were elucidated as 3-O-β- D-glucopyranosyl kaur-5, 16-dien-3β, 6, 13β-trihydroxy-7-oxo-18-oic acid methyl ester and 3-O-β-neohesperidosyl kaur-5, 16-dien-3β, 6, 13β-trihydroxy-7-oxo-18-oic acid methyl ester, respectively. The kaurene diterpenoid glycosides were first isolated and identified from fenugreek seeds. PMID:22950814

  6. Dehalogenation Activity of Selected Fungi Toward δ-Iodo-γ-Lactone Derived from trans,trans-Farnesol.

    PubMed

    Gliszczyńska, Anna; Gładkowski, Witold; Świtalska, Marta; Wietrzyk, Joanna; Szumny, Antoni; Gębarowska, Elżbieta; Wawrzeńczyk, Czesław

    2016-04-01

    Time-course of biotransformation of racemic trans-4-((E)-4',8'-dimethylnona-3',7'-dien-1-yl)-5-iodomethyl-4-methyldihydrofuran-2-one (1) in fungal and yeast cultures was investigated. In these conditions, the substrate 1 was enantioselectively dehalogenated yielding 4-((E)-4',8'-dimethylnona-3',7'-dien-1-yl)-4-methyl-5-methylenedihydrofuran-2-one (2) and its structure was established based on the spectroscopic data. The most effective biocatalyst used was Didymosphaeria igniaria, which catalyzed the process with highest rate and enantioselectivity (ee of product = 76%). The antiproliferative activity of δ-iodo-γ-lactone 1, product of its biotransformation 2, and starting substrate (farnesol) were evaluated toward two cancer cell lines: A549 (human lung adenocarcinoma) and HL-60 (human promyelocytic leukemia). PMID:26923572

  7. Essential-oil polymorphism in the 'resurrection plant' Myrothamnus moschatus and associated ethnobotanical knowledge.

    PubMed

    Randrianarivo, Emmanuel; Rasoanaivo, Philippe; Nicoletti, Marcello; Razafimahefa, Solofoniaina; Lefebvre, Manon; Papa, Fabrizio; Vittori, Sauro; Maggi, Filippo

    2013-11-01

    Gas chromatography/mass spectroscopy analysis (GC/MS) of essential oils obtained from populations of the resurrection plant Myrothamnus moschatus, growing in different areas of Madagascar, allowed identification of three main chemotypes in the species. The first one was provided by plants with a high content of trans-pinocarveol and pinocarvone; the second one involved plants with high percentages of limonene, cis- and trans-p-mentha-1(7),8-dien-2-ol, and β-selinene; and the third chemotype was characterized by plants with high levels of oxygenated sesquiterpenes such as caryophyllene oxide and α- and β-isomers of caryophylla-4(12),8(13)-dien-5-ol. Chemical data were supported by chemometric technique as the principal component analysis. Furthermore, the relationship between the dioecy and phytochemistry within one population was also considered. Finally, correlations between chemical variations and ethnobotanical data were assessed. PMID:24243607

  8. Hydrogenation and Transfer Hydrogenation Promoted by Tethered Ru-S Complexes: From Cooperative Dihydrogen Activation to Hydride Abstraction/Proton Release from Dihydrogen Surrogates.

    PubMed

    Lefranc, Alice; Qu, Zheng-Wang; Grimme, Stefan; Oestreich, Martin

    2016-07-11

    Hydrogenation and transfer hydrogenation of imines with cyclohexa-1,4-dienes, as well as with a representative Hantzsch ester dihydrogen surrogate, are reported. Both processes are catalyzed by tethered Ru-S complexes but differ in the activation mode of the dihydrogen source: cooperative activation of the H-H bond at the Ru-S bond leads to the corresponding Ru-H complex and protonation of the sulfur atom, whereas the same cationic Ru-S catalyst abstracts a hydride from a donor-substituted cyclohexa-1,4-diene to form the neutral Ru-H complex and a low-energy Wheland intermediate. A sequence of proton and hydride transfers on the imine substrate then yields an amine. The reaction pathways are analyzed computationally, and the established mechanistic pictures are in agreement with the experimental observations. PMID:27311877

  9. [Studies on chemical compounds of Chlorella sorokiniana].

    PubMed

    Zhang, Ling; Liu, Ping-huai; Wu, Jiao-na; Yang, Guo-fu; Suo, Yang-yang; Luo, Ning; Chen, Chen

    2015-04-01

    Chemical constituents of Chlorella sorokiniana were isolated and purified by repeated column chromatographies, over silicagel and Sephadex LH-20. Their structures were identified on the basis of physicochemical properties and spectroscopic data analysis. Five compounds were obtained from the petroleum ether extract of Chlorella sorokiniana, and their structures were identified as (22E, 24R)-5alpha, 3beta-epidioxiergosta-6, 22-dien-3beta-ol(1),(24S)-ergosta-7-en-3beta-ol(2), loliolide(3), stigmasta-7,22-dien-3beta,5alpha,6alpha-triol(4), and 3beta-hydroxy-5alpha,6alpha-epoxy-7-megastigmen-9-one(5). The main liposoluble fractions from Chlorella sorokiniana maiuly contain fatty acids, alkyl acids and olefine acids. Components 1-5 were isolated from the genus Chlorella for the first time. PMID:26281556

  10. A new global ionospheric model

    NASA Technical Reports Server (NTRS)

    Yip, K. W.; Vonroos, O. H.

    1975-01-01

    A new global ionospheric model was successfully implemented. The daytime portion of this model provides one-way ionospheric range corrections that compare favorably with those derived from the Mariner Venus/Mercury S- and X-band dual frequency Doppler data. For elevation angles, gamma higher than 30 deg and solar zenith angle less than 80 deg, this model provides calibrations accurate to a few centimeters. The calibrations provided by the nighttime model are also very reasonable. It is interesting to note that the daytime ionospheric calibrations derived from the current calibration scheme, DIEN/TIEN, are fairly close to those given by the new global model, especially in the temporal variations and thus the Doppler effects. The comparison between the nighttime model and DIEN/TIEN was based on the one-way ionospheric range corrections for three passes near the Mariner 9 encounter with Mars in 1971. They can differ by over 30%.

  11. Antioxidant and antifungal activities of Camellia sinensis (L.) Kuntze leaves obtained by different forms of production.

    PubMed

    Camargo, L E A; Pedroso, L S; Vendrame, S C; Mainardes, R M; Khalil, N M

    2016-06-01

    The antioxidant and anticandidal activities of leaves obtained from Camellia sinensis by non-fermentation (green and white teas), semi-fermentation (red tea) and fermentation method (black tea) were investigated. It was evaluated the total phenolic content by Folin-Ciocalteau assay; antioxidant capacities were evaluated in vitro using DPPH and ABTS radicals, hypochlorous acid and superoxide anion scavenger assays, induced hemolysis, lipid peroxidation by conjugated diene formation and myeloperoxidase activity. Anticandidal activity was performed on three strains of Candida spp. The results showed that non-fermented teas have a higher concentration of phenolic compounds, and then presented the best inhibitory activity of AAPH-induced hemolysis, the best inhibition of conjugated diene formation and more pronounced antioxidant activity in all tests. The highest anticandidal activity was obtained from fermented tea, followed by non-fermented tea. These results indicate that the antioxidant activity demonstrated has no direct relation with the anticandidal activity. PMID:26983085

  12. Determination of ideal-gas enthalpies of formation for key compounds: The 1988 project results

    NASA Astrophysics Data System (ADS)

    Steele, W. V.; Chirico, R. D.; Nguyen, A.; Hossenlopp, I. A.; Smith, N. K.

    1990-07-01

    The results of a study aimed at improvement of group contribution methodology for estimation of thermodynamic properties of organic substances are reported. Specific weakness where particular group-contribution terms were unknown, or estimated because of lack of experimental data, are addressed by experimental studies of enthalpies of combustion in the condensed phase and vapor pressure measurements. Ideal-gas enthalpies of formation are reported for 3-methylbuta 1,2-diene; 2,5-dimethylhexa 2,4-diene; acetaldoxime; N,N-diethyl hydroxylamine; 1-methylpyrrolidin-2-one; and phenanthrene. Solid and liquid phase enthalpies of formation at 298.15 K are determined for benzamide. Ring corrections, group terms, and next-nearest-neighbor interaction terms useful in the application of group contribution correlations are derived.

  13. Catalysis of the Aza-Diels-Alder Reaction by Hydrogen and Halogen Bonds.

    PubMed

    Nziko, Vincent de Paul N; Scheiner, Steve

    2016-03-18

    The combination of H2C═NH and cis-1,3-butadiene to form a six-membered ring was examined by quantum calculations. The energy barrier for this reaction is substantially lowered by the introduction of an imidazolium catalyst with either a H or halogen (X) atom in the 2-position, which acts via a H or halogen bond to the N atom of the imine, respectively. X = I has the largest effect, and Cl the smallest; Br and H are roughly equivalent. The catalyst retards the formation of the incipient N-C bond from imine to diene while simultaneously accelerating the C-C bond formation. The energy of the π* LUMO of the imine is lowered by the catalyst, which thereby enhances charge transfer from the diene to the imine. Assessment of free energies suggests catalytic rate acceleration by as much as 4-6 orders of magnitude. PMID:26907727

  14. Ring-closing metathesis as key step in the synthesis of Luffarin I, 16-epi-Luffarin I and Luffarin A.

    PubMed

    Urosa, Aitor; Marcos, Isidro S; Díez, David; Plata, Gabriela B; Padrón, José M; Basabe, Pilar

    2016-05-01

    Natural sesterterpenolides, luffarin I and luffarin A, from Luffariella geometrica have been synthesized, and this is the first reported synthesis of luffarin A. The Yamaguchi esterification of the nor-diterpenic fragment, obtained from 2.8-15μM, with the appropriate furane alcohols yielded the necessary diene intermediates for the synthesis of the target molecules. The key strategic step in this synthesis was the ring-closing metathesis (RCM) reaction of the diene intermediates. This strategy allowed for the synthesis of 16-epi-luffarin I and analogues for structure-activity relationship (SAR) studies. The most active compound exhibited antiproliferative activity against a panel of six human solid tumour cell lines with [Formula: see text] values in the range 2.8-15 M. PMID:26486134

  15. Exploring the intrinsic polar [4+2(+)] cycloaddition reactivity of gaseous carbosulfonium and carboxonium ions.

    PubMed

    Basher, Muftah M; Corilo, Yuri E; Sparrapan, Regina; Benassi, Mario; Augusti, Rodinei; Eberlin, Marcos N; Riveros, José M

    2012-11-01

    Gas-phase reactions of model carbosulfonium ions (CH(3)-S(+)=CH(2;) CH(3)CH(2)-S(+)=CH(2) and Ph-S(+)=CH(2)) and an O-analogue carboxonium ion (CH(3)-O(+)=CH(2)) with acyclic (isoprene, 1,3-butadiene, methyl vinyl ketone) and cyclic (1,3-cyclohexadiene, thiophene, furan) conjugated dienes were systematically investigated by pentaquadrupole mass spectrometry. As corroborated by B3LYP/6-311 G(d,p) calculations, the carbosulfonium ions first react at large extents with the dienes forming adducts via simple addition. The nascent adducts, depending on their stability and internal energy, react further via two competitive channels: (1) in reactions with acyclic dienes via cyclization that yields formally [4+2(+)] cycloadducts, or (2) in reactions with the cyclic dienes via dissociation by HSR loss that yields methylenation (net CH(+) transfer) products. In great contrast to its S-analogues, CH(3)-O(+)=CH(2) (as well as C(2)H(5)-O(+)=CH(2) and Ph-O(+)=CH(2) in reactions with isoprene) forms little or no adduct and proton transfer is the dominant reaction channel. Isomerization to more acidic protonated aldehydes in the course of reaction seems to be the most plausible cause of the contrasting reactivity of carboxonium ions. The CH(2)=CH-O(+)=CH(2) ion forms an abundant [4+2(+)] cycloadduct with isoprene, but similar to the behavior of such α,β-unsaturated carboxonium ions in solution, seems to occur across the C=C bond. PMID:23147832

  16. Hydrocarbon compositions containing polyolefin graft polymers

    SciTech Connect

    Kapuscinski, M.M.; Liu, C.S.; Hart, W.P.; Grina, L.D.

    1987-02-03

    A graft polymer is described comprising an oil-soluble, substantially linear, carbon-carbon backbone polymer having graft polymerized thereon units derived from, as a functional monomer, the reaction product of (i) an unsaturated aldehyde or ketone and (ii) a primary or secondary amine which contains at least one nitrogen atom in a heterocyclic ring. The graft polymer is also described wherein the backbone polymer is a copolymer of ethylene-propylene or a terpolymer of ethylene-propylene-diene monomer.

  17. Photochromism of heterocyclic systems

    NASA Technical Reports Server (NTRS)

    Silversmith, E. F.

    1972-01-01

    The preparations of photochromic dimers of a 2-aryl-4,5-di-phenylimidazyl radical and of a 2,5-diphenyl-3,4-isobenzopyrrole with different substituents in the homocyclic ring are reported. Of the dienes investigated, only 1-4-diphenyl-1,3-butadiene and 2,3-dimethyl-1,3-butadiene gave isolable amounts of the Diels-Adler adducts.

  18. Microbial Aromatization of Steroids into Equilin

    PubMed Central

    Sehgal, S. N.; Vézina, Claude

    1970-01-01

    This report describes the bioconversion of 19-hydroxy-androsta-4, 7-diene-3, 17-dione into equilin with Nocardia rubra. Through mutation and improvement of medium and of conditions, the bioconversion could be improved to yield 40% equilin for a substrate concentration of 1 g/liter. Aromatization of several other 19-hydroxy and 19-nor substrates of the androstene series is reported, and the influence of various substitutions of the substrate molecule on aromatization is discussed. PMID:5492438

  19. Enantiomeric resolution and absolute configuration of asymmetric derivatives of 3,7-dimethylenebicyclo(3. 3. 1)nonane. Synthesis of chiral derivatives of adamantane

    SciTech Connect

    Krasutskii, P.A.; Rodionov, V.N.; Chesskaya, N.S.; Yurchenko, A.G.

    1986-01-10

    A new method was developed for the enantiomeric resolution of asymmetric derivatives of 3,7-dimethylenebicyclo(3.3.1)nonane by liquid chromatography on a chiral sorbent, i.e., silica gel impregnated with silver d-camphor-10-sulfonate. During transannular electrophilic cyclization and photocyclization the enantiomeric dienes, the absolute configurations of which were determined by means of the circular dichromism spectra, form chiral derivatives of adamantane with full retention of the optical purity.

  20. Efficient, Selective, and Green

    PubMed Central

    Smith, Craig R.; RajanBabu, T. V.

    2009-01-01

    Fine tuning of the biaryl and amino moieties of Feringa’s phosphoramidite ligands yields structurally simpler, yet more efficient and selective, ligands for asymmetric hydrovinylation of vinylarenes and acylic 1,3-dienes. The enantioselectivities and yields observed in the formation of the 3-arylbutenes are among the highest for all asymmetric catalytic processes reported to date for the synthesis of intermediates for the widely used antiinflammatory 2-arylpropionic acids including naproxen, ibuprofen, fenoprofen, and flurbiprofen. PMID:18351772

  1. Systematic structure modifications of multitarget prostate cancer drug candidate galeterone to produce novel androgen receptor down-regulating agents as an approach to treatment of advanced prostate cancer.

    PubMed

    Purushottamachar, Puranik; Godbole, Abhijit M; Gediya, Lalji K; Martin, Marlena S; Vasaitis, Tadas S; Kwegyir-Afful, Andrew K; Ramalingam, Senthilmurugan; Ates-Alagoz, Zeynep; Njar, Vincent C O

    2013-06-27

    As part of our program to explore the influence of small structural modifications of our drug candidate 3β-(hydroxy)-17-(1H-benzimidazol-1-yl)androsta-5,16-diene (galeterone, 5) on the modulation of the androgen receptor (AR), we have prepared and evaluated a series of novel C-3, C-16, and C-17 analogues. Using structure activity analysis, we established that the benzimidazole moiety at C-17 is essential and optimal and also that hydrophilic and heteroaromatic groups at C-3 enhance both antiproliferative (AP) and AR degrading (ARD) activities. The most potent antiproliferative compounds were 3β-(1H-imidazole-1-carboxylate)-17-(1H-benzimidazol-1-yl)androsta-5,16-diene (47), 3-((EZ)-hydroximino)-17-(1H-benzimidazol-1-yl)androsta-4,16-diene (36), and 3β-(pyridine-4-carboxylate)-17-(1H-benzimidazol-1-yl)androsta-5,16-diene (43), with GI50 values of 0.87, 1.91, and 2.57 μM, respectively. Compared to 5, compound 47 was 4- and 8-fold more potent with respect to AP and ARD activities, respectively. Importantly, we also discovered that our compounds, including 5, 36, 43, and 47, could degrade both full-length and truncated ARs in CWR22rv1 human prostate cancer cells. With these activities, they have potential for development as new drugs for the treatment of all forms of prostate cancer. PMID:23713567

  2. Toxicity of Pyrolysis Gases from Elastomers

    NASA Technical Reports Server (NTRS)

    Hilado, Carlos J.; Kosola, Kay L.; Solis, Alida N.; Kourtides, Demetrius A.; Parker, John A.

    1977-01-01

    The toxicity of the pyrolysis gases from six elastomers was investigated. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acryltonitrile rubber exhibited the greatest toxicity under these test conditions; carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

  3. Systematic Structure Modifications of Multi-target Prostate Cancer Drug Candidate Galeterone to Produce Novel Androgen Receptor Down-regulating Agents as an Approach to Treatment of Advanced Prostate Cancer

    PubMed Central

    Purushottamachar, Puranik; Godbole, Abhijit M.; Gediya, Lalji K.; Martin, Marlena S.; Vasaitis, Tadas S.; Kwegyir-Afful, Andrew K.; Ramalingam, Senthilmurugan; Ates-Alagoz, Zeynep; Njar, Vincent C. O.

    2013-01-01

    As part of our program to explore the influence of small structural modifications of our drug candidate, 3β-(hydroxy)-17-(1H-benzimidazol-1-yl)-androsta-5,16-diene (galeterone, 5) on the modulation of the androgen receptor (AR), we have prepared and evaluated a series of novel C-3, C-16 and C-17 analogs. Using structure activity analysis, we established that the benzimidazole moiety at C-17 is essential and optimal and also that hydrophilic and heteroaromatic groups at C-3 enhance both anti-proliferative (AP) and AR degrading (ARD) activities. The most potent anti-proliferative compounds were 3β-(1H-imidazole-1-carboxylate)- 17-(1H-benzimidazol-1-yl)-androsta-5,16-diene (47), 3-((EZ)-hydroximino)-17-(1Hbenzimidazol- 1-yl)-androsta-4,16-diene (36), 3β-(pyridine-4-carboxylate)-17-(1H-benzimidazol- 1-yl)-androsta-5,16-diene (43), with GI50 values of 0.87, 1.91 and 2.57 μM, respectively. Compared to 5, compound 47 was 4- and 8-fold more potent with respect to AP and ARD activities, respectively. Importantly, we also discovered that our compounds, including 5, 36, 43 and 47 could degrade both full-length and truncated AR in CWR22rv1 human prostate cancer cells. With these activities, their potential for development as new drugs for the treatment of all forms of prostate cancer. PMID:23713567

  4. Total Synthesis of (−)-Calyciphylline N

    PubMed Central

    Shvartsbart, Artem; Smith, Amos B.

    2014-01-01

    The total synthesis of the architecturally complex Daphniphyllum alkaloid (−)-calyciphylline N has been achieved. Highlights of the synthesis include a Et2AlCl promoted, highly stereoselective susbtrate controlled intramolecular Diels-Alder reaction, a transannular enolate alkylation, an effective Stille carbonylation/Nazarov cyclization sequence, and a high risk dia-stereoselective hydrogenation of a fully substituted conjugated diene ester. PMID:24319987

  5. The Daphniphyllum Alkaloids: Total Synthesis of (−)-Calyciphylline N

    PubMed Central

    2016-01-01

    Presented here is a full account on the development of a strategy culminating in the first total synthesis of the architecturally complex daphniphyllum alkaloid, (−)-calyciphylline N. Highlights of the approach include a highly diastereoselective, intramolecular Diels–Alder reaction of a silicon-tethered acrylate; an efficient Stille carbonylation of a sterically encumbered vinyl triflate; a one-pot Nazarov cyclization/proto-desilylation sequence; and the chemoselective hydrogenation of a fully substituted diene ester. PMID:25756504

  6. Alternate biosynthesis of valerenadiene and related sesquiterpenes.

    PubMed

    Paknikar, Shashikumar K; Kadam, Shahuraj H; Ehrlich, April L; Bates, Robert B

    2013-09-01

    It is proposed that the biosynthesis of the sesquiterpene valerenadiene, a key intermediate in the biosynthesis of a sedative in valerian, involves cyclopropane and not cyclobutane intermediates and includes as a key step a cyclopropylcarbinylcation-cyclopropylcarbinylcation rearrangement analogous to the one observed in the conversion of presqualene to squalene in triterpene and steroid biosynthesis. Similar mechanisms are proposed for the biosynthesis of the related sesquiterpenes pacifigorgiol, tamariscene and (+)-pacifigorgia-1,10-diene. PMID:24273843

  7. Ring Expansion of Cyclic 1,2-Diols to form Medium Sized Rings via Ruthenium Catalyzed Transfer Hydrogenative [4+2] Cycloaddition

    PubMed Central

    Kasun, Zachary A.; Geary, Laina M.

    2014-01-01

    A new method for the ring expansion of cyclic diols is described. Using improved conditions for the ruthenium(0) catalyzed cycloaddition of cyclic 1,2-diols with 1,3-dienes, fused [n.4.0] bicycles 3a–3r (n = 3–6) are formed, which upon exposure to iodosobenzene diacetate engage in oxidative cleavage to form the 9–12 membered rings 4a–4r. PMID:24890278

  8. Taxol biosynthesis: differential transformations of taxadien-5 alpha-ol and its acetate ester by cytochrome P450 hydroxylases from Taxus suspension cells.

    PubMed

    Wheeler, A L; Long, R M; Ketchum, R E; Rithner, C D; Williams, R M; Croteau, R

    2001-06-15

    The biosynthesis of the diterpenoid antineoplastic drug Taxol in Taxus species involves the cyclization of the ubiquitous isoprenoid intermediate geranylgeranyl diphosphate to taxa-4(5),11(12)-diene followed by cytochrome P450-mediated hydroxylation (with allylic rearrangement) of this olefin precursor to taxa-4(20),11(12)-dien-5 alpha-ol, and further oxygenation and acylation reactions. Based on the abundances of naturally occurring taxoids, the subsequent order of oxygenation of the taxane core is considered to occur at C10, then C2 and C9, followed by C13, and finally C7 and C1. Circumstantial evidence suggests that the acetylation of taxadien-5 alpha-ol may constitute the third specific step of Taxol biosynthesis. To determine whether taxadienol or the corresponding acetate ester serves as the direct precursor of subsequent oxygenation reactions, microsomal preparations isolated from induced Taxus cells and optimized for cytochrome P450 catalysis were incubated with each potential substrate. Both taxadienol and taxadienyl acetate were oxygenated to the level of a diol and to higher polyols at comparable rates by cytochrome P450 enzymes of the microsomal preparation. Preparative-scale incubation allowed the isolation of sufficient quantities of the diol derived from taxadienol to permit the NMR-based structural elucidation of this metabolite as taxa-4(20),11(12)-dien-5 alpha,13 alpha-diol, which may represent an alternate route of taxoid metabolism in induced cells. GC-MS-based structural definition of the diol monoacetate derived in microsomes from taxadienyl acetate confirmed this metabolite as taxa-4(20),11(12)-dien-5 alpha-acetoxy-10 beta-ol, thereby indicating that acetylation at C5 of taxadienol precedes the cytochrome P450-mediated insertion of the C10-beta-hydroxyl group of Taxol. PMID:11396929

  9. Stereoselective Total Synthesis of Atractylodemayne A, a Conjugated 2(E),8(Z),10(E)-Triene-4,6-diyne.

    PubMed

    Schmidt, Bernd; Audörsch, Stephan

    2016-03-01

    The first total synthesis of the polyacetylene natural product atractylodemayne A is reported. Stereoselective construction of the conjugated 8(Z),10(E)-diene moiety was achieved through a tethered ring-closing metathesis approach, comprising a Ru-catalyzed RCM followed by a base-induced elimination. A Pd-catalyzed Cadiot-Chodkiewicz coupling was used for the synthesis of the diyne. Overall, atractylodemayne A was synthesized in nine steps for the longest linear sequence. PMID:26886865

  10. Total Synthesis of (±)-Integrifolin.

    PubMed

    Shimomaki, Katsuya; Kusama, Hiroyuki; Iwasawa, Nobuharu

    2016-07-11

    The total synthesis of (±)-integrifolin has been achieved for the first time through the stereoselective preparation of the bicyclo[5.3.0]decane skeleton based on the tungsten-catalyzed cyclization of acyclic trienynes under photoirradiation conditions. Further key transformations of the cyclized product are the Tamao oxidation through cyclic silyl ether, the introduction of two oxygen functionalities by the oxidation of the diene and the construction of three exo-methylene moieties. PMID:27147582

  11. Biotransformation of substituted benzoates to the corresponding cis-diols by an engineered strain of Pseudomonas oleovorans producing the TOL plasmid-specified enzyme toluate-1,2-dioxygenase

    SciTech Connect

    Wubbolts, M.G.; Timmis, K.N. )

    1990-02-01

    The conversion of substituted benzoates into 1,2-cis-dihydroxycyclohexa-3,5-diene carboxylic acids (cis-diols) was affected by using Escherichia coli and Pseudomonas recombinants carrying the xylXYZ genes originating from the Pseudomonas putida mt-2 TOL plasmid, thus producing toluate-1,2-dioxygenase. Pseudomonas oleovorans GPo12 recombinants readily produced meta-and para-substituted cis-diols, but were limited in their oxidation of ortho-substituted substrates.

  12. Nicotiana benthamiana as a Production Platform for Artemisinin Precursors

    PubMed Central

    van Herpen, Teun W. J. M.; Cankar, Katarina; Nogueira, Marilise; Bosch, Dirk; Bouwmeester, Harro J.; Beekwilder, Jules

    2010-01-01

    Background Production of pharmaceuticals in plants provides an alternative for chemical synthesis, fermentation or natural sources. Nicotiana benthamiana is deployed at commercial scale for production of therapeutic proteins. Here the potential of this plant is explored for rapid production of precursors of artemisinin, a sesquiterpenoid compound that is used for malaria treatment. Methodology/Principal Findings Biosynthetic genes leading to artemisinic acid, a precursor of artemisinin, were combined and expressed in N. benthamiana by agro-infiltration. The first committed precursor of artemisinin, amorpha-4,11-diene, was produced upon infiltration of a construct containing amorpha-4,11-diene synthase, accompanied by 3-hydroxy-3-methylglutaryl-CoA reductase and farnesyl diphosphate synthase. Amorpha-4,11-diene was detected both in extracts and in the headspace of the N. benthamiana leaves. When the amorphadiene oxidase CYP71AV1 was co-infiltrated with the amorphadiene-synthesizing construct, the amorpha-4,11-diene levels strongly decreased, suggesting it was oxidized. Surprisingly, no anticipated oxidation products, such as artemisinic acid, were detected upon GC-MS analysis. However, analysis of leaf extracts with a non-targeted metabolomics approach, using LC-QTOF-MS, revealed the presence of another compound, which was identified as artemisinic acid-12-β-diglucoside. This compound accumulated to 39.5 mg.kg−1 fwt. Apparently the product of the heterologous pathway that was introduced, artemisinic acid, is further metabolized efficiently by glycosyl transferases that are endogenous to N. benthamiana. Conclusion/Significance This work shows that agroinfiltration of N. bentamiana can be used as a model to study the production of sesquiterpenoid pharmaceutical compounds. The interaction between the ectopically introduced pathway and the endogenous metabolism of the plant is discussed. PMID:21151979

  13. A Functional Genomics Approach to Tanshinone Biosynthesis Provides Stereochemical Insights

    PubMed Central

    2009-01-01

    Tanshinones are abietane-type norditerpenoid quinone natural products that are the bioactive components of the Chinese medicinal herb Salvia miltiorrhiza Bunge. The initial results from a functional genomics-based investigation of tanshinone biosynthesis, specifically the functional identification of the relevant diterpene synthases from S. miltiorrhiza, are reported. The cyclohexa-1,4-diene arrangement of the distal ring poises the resulting miltiradiene for the ensuing aromatization and hydroxylation to ferruginol suggested for tanshinone biosynthesis. PMID:19905026

  14. A functional genomics approach to tanshinone biosynthesis provides stereochemical insights.

    PubMed

    Gao, Wei; Hillwig, Matthew L; Huang, Luqi; Cui, Guanghong; Wang, Xueyong; Kong, Jianqiang; Yang, Bin; Peters, Reuben J

    2009-11-19

    Tanshinones are abietane-type norditerpenoid quinone natural products that are the bioactive components of the Chinese medicinal herb Salvia miltiorrhiza Bunge. The initial results from a functional genomics-based investigation of tanshinone biosynthesis, specifically the functional identification of the relevant diterpene synthases from S. miltiorrhiza, are reported. The cyclohexa-1,4-diene arrangement of the distal ring poises the resulting miltiradiene for the ensuing aromatization and hydroxylation to ferruginol suggested for tanshinone biosynthesis. PMID:19905026

  15. Chain Walking of Allylrhodium Species Towards Esters During Rhodium‐Catalyzed Nucleophilic Allylations of Imines

    PubMed Central

    Martínez, Jose I.; Smith, Joshua J.; Hepburn, Hamish B.

    2015-01-01

    Abstract Allylrhodium species derived from δ‐trifluoroboryl β,γ‐unsaturated esters undergo chain walking towards the ester moiety. The resulting allylrhodium species react with imines to give products containing two new stereocenters and a Z‐alkene. By using a chiral diene ligand, products can be obtained with high enantioselectivities, where a pronounced matched/mismatched effect with the chirality of the allyltrifluoroborate is evident. PMID:26756445

  16. Chain Walking of Allylrhodium Species Towards Esters During Rhodium-Catalyzed Nucleophilic Allylations of Imines.

    PubMed

    Martínez, Jose I; Smith, Joshua J; Hepburn, Hamish B; Lam, Hon Wai

    2016-01-18

    Allylrhodium species derived from δ-trifluoroboryl β,γ-unsaturated esters undergo chain walking towards the ester moiety. The resulting allylrhodium species react with imines to give products containing two new stereocenters and a Z-alkene. By using a chiral diene ligand, products can be obtained with high enantioselectivities, where a pronounced matched/mismatched effect with the chirality of the allyltrifluoroborate is evident. PMID:26756445

  17. Delta8(14)-steroids in the bacterium Methylococcus capsulatus.

    PubMed Central

    Bouvier, P; Rohmer, M; Benveniste, P; Ourisson, G

    1976-01-01

    The 4,4-dimethyl and 4alpha-methyl sterols of the bacterium Methylococcus capsulatus were identified as 4,4-dimethyl- and 4alpha-methyl-5alpha-cholest-8(14)-en-3beta-ol and 4,4-dimethyl- and 4alpha-methyl-5alpha-cholesta-8(14),24-dien-3beta-ol. Sterol biosynthesis is blocked at the level of 4alpha-methyl delta8(14)-sterols. PMID:999649

  18. Diels-Alder Reactions of Furans with Itaconic Anhydride: Overcoming Unfavorable Thermodynamics.

    PubMed

    Pehere, Ashok D; Xu, Shu; Thompson, Severin K; Hillmyer, Marc A; Hoye, Thomas R

    2016-06-01

    Unfavorable thermodynamics often render furans reluctant to engage in high-yielding Diels-Alder (DA) cycloaddition reactions. Here, we report the highly efficient conversion of the biosourced reactants itaconic anhydride (IA) and furfuryl alcohol (FA) to a single DA adduct. The free energy advantages provided by anhydride ring opening and crystal lattice energy of the product overcome the loss of aromaticity of the furanoid diene. Detailed (1)H NMR studies provided valuable insights about relevant kinetic and thermodynamic features. PMID:27214494

  19. Hydrogenation of unsaturated, aromatic, and heterocyclic compounds with polymer-supported catalysts

    SciTech Connect

    Karakhanov, E.A.; Pshezhetskii, V.S.; Dedov, A.G.; Loktev, A.S.; Lebedeva, T.S.

    1984-04-01

    The authors synthesized and studied catalysts based upon complexes of platinum, palladium, rhodium, and nickel with the following polymeric microligands: copolymers of styrene with maleic acid (S-MA), copolymers of maleic acid with methyl methacrylate (MA-MMA), and polyacrylic acid (PAA). The catalysts showed high activity and selectivity in the hydrogenation of furan and its derivatives, benzofuran, benzodioxane, benzene, nitrobenzene, phenol, olefins and cyclic olefins, and cyclic dienes. 2 tables.

  20. Antimicrobial Diterpenes from Azorella Species Against Gram-Positive Bacteria.

    PubMed

    Donoso, Viviana; Bacho, Mitchell; Núiñez, Solange; Rovirosa, Juana; San-Martin, Aurelio; Leiva, Sergio

    2015-11-01

    The present study was aimed at evaluating the antibacterial activity of mulinane and azorellane diterpenes isolated from the Andean plants Azorella compacta and A. trifoliolata and semisynthetic derivatives against reference and multidrug-resistant strains. The results revealed that the semisynthetic compound 7-acetoxy-mulin-9,12-diene (5) exhibited antibacterial activity against reference and multidrug-resistant strains of Staphylococcus aureus and moderate antimycobacterial activity against Mycobacterium smegmatis ATCC 14468. PMID:26749825

  1. Synthesis and activity of novel 16-dehydropregnenolone acetate derivatives as inhibitors of type 1 5α-reductase and on cancer cell line SK-LU-1.

    PubMed

    Silva-Ortiz, Aylin Viviana; Bratoeff, Eugene; Ramírez-Apan, Teresa; Heuze, Yvonne; Sánchez, Araceli; Soriano, Juan; Cabeza, Marisa

    2015-12-15

    Testosterone (T) plays a crucial role in prostate growth. In androgen-dependent tissues T is reduced to dihydrotestosterone (DHT) because of the presence of the 5α-reductase enzyme. This androgen is more active than T, since it has a higher affinity for the androgen receptor (AR). When this mechanism is altered, androgen-dependent diseases, including prostate cancer, could result. The aim of this study was to synthesize several 16-dehydropregnenolone acetate derivatives containing a triazole ring at C-21 and a linear or alicyclic ester moiety at C-3 of the steroidal skeleton. These steroids were designed as potential inhibitors of the activity of both types (1 and 2) of 5α-reductase. The cytotoxic activity of these compounds was also evaluated on a panel of PC-3, MCF7, and SK-LU-1 human cancer cell lines. The results from this study showed that with the exception of steroids 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-propionate and 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-pentanoate, the compounds exhibit a lower inhibitory activity for both isoenzymes of 5α-reductase than finasteride. Furthermore the 3β-hydroxy-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-20-one and 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-acetate derivatives display 80% cytotoxic activity on the SK-LU-1 cell line. These results also indicated that the triazole derivatives, which have a hydroxyl or acetoxy group at C-3, could have an anticancer effect, whereas the derivatives with a alicyclic ester group at C-3 do not show biological activity. PMID:26631442

  2. Phytotoxic Potential of Secondary Metabolites and Semisynthetic Compounds from Endophytic Fungus Xylaria feejeensis Strain SM3e-1b Isolated from Sapium macrocarpum.

    PubMed

    García-Méndez, Marbella Claudia; Macías-Ruvalcaba, Norma A; Lappe-Oliveras, Patricia; Hernández-Ortega, Simón; Macías-Rubalcava, Martha Lydia

    2016-06-01

    Bioactivity-directed fractionation of the combined culture medium and mycelium extract of the endophytic fungus Xylaria feejeensis strain SM3e-1b, isolated from Sapium macrocarpum, led to the isolation of three known natural products: (4S,5S,6S)-4-hydroxy-3-methoxy-5-methyl-5,6-epoxycyclohex-2-enone or coriloxine, 1; 2-hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 2; and 2,6-dihydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione or fumiquinone B, 3. This is the first report of compound 3 being isolated from this species. Additionally, four new derivatives of coriloxine were prepared: (4R,5S,6R)-6-chloro-4,5-dihydroxy-3-methoxy-5-methylcyclohex-2-enone, 4; 6-hydroxy-5-methyl-3-(methylamino)cyclohexa-2,5- diene-1,4-dione, 5; (4R,5R,6R)-4,5-dihydroxy-3-methoxy-5-methyl-6-(phenylamino)cyclohex-2-enone, 6; and 2-((4-butylphenyl)amino)-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 7. X-ray analysis allowed us to unambiguously determine the structures and absolute configuration of semisynthetic derivatives 4, 5, and 6. The phytotoxic activity of the three isolated natural products and the coriloxine derivatives is reported. Germination of the seed, root growth, and oxygen uptake of the seedlings of Trifolium pratense, Medicago sativa, Panicum miliaceum, and Amaranthus hypochondriacus were significantly inhibited by all of the tested compounds. In general, they were more effective inhibiting root elongation than suppressing the germination and seedling oxygen uptake processes as shown by their IC50 values. PMID:27159617

  3. Cadinane sesquiterpenes from Curcuma parviflora.

    PubMed

    Sadhu, Samir Kumar; Tamaki, Mayu; Ohtsuki, Takashi; Toume, Kazufumi; Koyano, Takashi; Kowithayakorn, Thaworn; Ishibashi, Masami

    2009-04-01

    Two new cadinane sesquiterpenes (1 and 2) were isolated from Curcuma parviflora, and their structures were elucidated by spectroscopic data. Compound 1, 4alpha-acetoxycadina-2,9-diene-1,8-dione, possesses two conjugated enone chromophores, while compound 2, 1alpha,3alpha,4beta-trihydroxy-9-cadinen-8-one, has an enone moiety with three hydroxy groups. Isolation of these cadinane monomers may reasonably suggest that parviflorenes are biogenetically classified as cadinane dimers. PMID:19239239

  4. The daphniphyllum alkaloids: total synthesis of (-)-calyciphylline N.

    PubMed

    Shvartsbart, Artem; Smith, Amos B

    2015-03-18

    Presented here is a full account on the development of a strategy culminating in the first total synthesis of the architecturally complex daphniphyllum alkaloid, (-)-calyciphylline N. Highlights of the approach include a highly diastereoselective, intramolecular Diels-Alder reaction of a silicon-tethered acrylate; an efficient Stille carbonylation of a sterically encumbered vinyl triflate; a one-pot Nazarov cyclization/proto-desilylation sequence; and the chemoselective hydrogenation of a fully substituted diene ester. PMID:25756504

  5. A Synthesis of the Chlorosulfolipid Mytilipin A via a Longest Linear Sequence of Seven Steps

    PubMed Central

    Chung, Won-jin; Carlson, Joseph S.; Bedke, D. Karl

    2013-01-01

    The chlorosulfolipid mytilipin A has been synthesized in racemic form in only seven steps and in enantioenriched form in eight steps. Key transformations include a highly diastereoselective bromoallylation of a sensitive α,β-dichloroaldehyde, a kinetic resolution of a complex vinyl epoxide, a convergent and highly Z-selective alkene cross metathesis, and a chemoselective and diastereoselective dichlorination of a complex diene. PMID:23929596

  6. [Study of pantothenic acid derivatives as cardiac protectors in a model of experimental ischemia and reperfusion of the isolated heart].

    PubMed

    Kumerova, A O; Utno, L Ia; Lipsberga, Z E; Shkestere, I Ia

    1992-04-01

    An isolated heart model with experimental ischemia and reperfusion was used to show effective decrease in lactate, increase in ATP content and prevention of conjugated dienes accumulation in the myocardium by derivatives of pantothenic acid: panthenol (9.0 mg/kg), calcium pantothenate (15.6 mg/kg) and by these ones applied simultaneously as ingredients of perfusate (25 microM) in postischemic period. In that way derivatives of pantothenic acid should be regarded as cardiac protectors. PMID:1391892

  7. Aerobic palladium(II)-catalyzed dehydrogenation of cyclohexene-1-carbonyl indole amides: an indole-directed aromatization.

    PubMed

    Kandukuri, Sandeep R; Oestreich, Martin

    2012-10-01

    A palladium(II)-catalyzed oxidative dehydrogenation of cyclohexene-1-carbonyl indole amides yielding the corresponding benzoylindoles is reported. The new aromatization is also applied to functionalized indoles such as tryptamine and tryptophan. The tethered indole is likely acting as a directing group for allylic C-H bond activation, and there is evidence for a mechanism proceeding through 1,3-diene formation followed by aromatization. PMID:22950832

  8. New applications of Ziegler-Natta organometallic catalysts

    SciTech Connect

    Noskova, N.H.; Sokol'skii, D.V.

    1983-05-01

    The composition of Ziegler-Natta organometallic catalysts was discussed. These catalysts were found to be a set of definite complexes, including a polynuclear cluster complex, in dynamic equilibrium with each other. New applications were found for Ziegler-Natta catalysts, specifically, use for the mild activation of alkanes, reduction of carbon monoxide, and positional isomerization of unconjugated dienes into conjugated analogs which are promising in metal complex catalysis.

  9. Molecular docking simulation studies on potent butyrylcholinesterase inhibitors obtained from microbial transformation of dihydrotestosterone

    PubMed Central

    2013-01-01

    Background Biotransformation is an effective technique for the synthesis of libraries of bioactive compounds. Current study on microbial transformation of dihydrotestosterone (DHT) (1) was carried out to produce various functionalized metabolites. Results Microbial transformation of DHT (1) by using two fungal cultures resulted in potent butyrylcholinesterase (BChE) inhibitors. Biotransformation with Macrophomina phaseolina led to the formation of two known products, 5α-androstan-3β,17β-diol (2), and 5β-androstan-3α,17β-diol (3), while biotransformation with Gibberella fujikuroi yielded six known metabolites, 11α,17β-dihydroxyandrost-4-en-3-one (4), androst-1,4-dien-3,17-dione (5), 11α-hydroxyandrost-4-en-3,17-dione (6), 11α-hydroxyandrost-1,4-dien-3,17-dione (7), 12β-hydroxyandrost-1,4-dien-3,17-dione (8), and 16α-hydroxyandrost-1,4-dien-3,17-dione (9). Metabolites 2 and 3 were found to be inactive, while metabolite 4 only weakly inhibited the enzyme. Metabolites 5–7 were identified as significant inhibitors of BChE. Furthermore, predicted results from docking simulation studies were in complete agreement with experimental data. Theoretical results were found to be helpful in explaining the possible mode of action of these newly discovered potent BChE inhibitors. Compounds 8 and 9 were not evaluated for enzyme inhibition activity both in vitro and in silico, due to lack of sufficient quantities. Conclusion Biotransformation of DHT (1) with two fungal cultures produced eight known metabolites. Metabolites 5–7 effectively inhibited the BChE activity. Cholinesterase inhibition is among the key strategies in the management of Alzheimer’s disease (AD). The experimental findings were further validated by in silico inhibition studies and possible modes of action were deduced. PMID:24103815

  10. 3-Bromopentadienylsilane: A new reagent for the introduction of a functional pentadienyl unit with fixed configuration

    PubMed

    Roux; Santelli; Parrain

    2000-06-15

    The (Z)-1-trimethylsilyl-3-bromopenta-2,4-diene 3 was prepared through a sequence involving the reductive silylation of butadiene, dibromocarbene addition on the resulting disilane 1, and thermolytic ring opening. With aldehydes, this new pentadienylsilane reacts exclusively via an S(E)' ' pathway. In the presence of an alcohol or a carbamate under Lewis acid activation, 3 yields, respectively, bromopentadienyl ethers or bromopentadienyl-protected amines. PMID:10880205

  11. Wild Bitter Melon Leaf Extract Inhibits Porphyromonas gingivalis-Induced Inflammation: Identification of Active Compounds through Bioassay-Guided Isolation.

    PubMed

    Tsai, Tzung-Hsun; Huang, Wen-Cheng; Ying, How-Ting; Kuo, Yueh-Hsiung; Shen, Chien-Chang; Lin, Yin-Ku; Tsai, Po-Jung

    2016-01-01

    Porphyromonas gingivalis has been identified as one of the major periodontal pathogens. Activity-directed fractionation and purification processes were employed to identify the anti-inflammatory active compounds using heat-killed P. gingivalis-stimulated human monocytic THP-1 cells in vitro. Five major fractions were collected from the ethanol/ethyl acetate extract of wild bitter melon (Momordica charantia Linn. var. abbreviata Ser.) leaves and evaluated for their anti-inflammatory activity against P. gingivalis. Among the test fractions, Fraction 5 effectively decreased heat-killed P. gingivalis-induced interleukin (IL)-8 and was subjected to separation and purification by using chromatographic techniques. Two cucurbitane triterpenoids were isolated from the active fraction and identified as 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol (1) and 3β,7β,25-trihydroxycucurbita-5,23-dien-19-al (2) by comparing spectral data. Treatments of both compounds in vitro potently suppressed P. gingivalis-induced IL-8, IL-6, and IL-1β levels and the activation of mitogen-activated protein kinase (MAPK) in THP-1 cells. Both compounds effectively inhibited the mRNA levels of IL-6, tumor necrosis factor (TNF)-α, and cyclooxygenase (COX)-2 in P. gingivalis-stimulated gingival tissue of mice. These findings imply that 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol and 3β,7β,25-trihydroxycucurbita-5,23-dien-19-al could be used for the development of novel therapeutic approaches against P. gingivalis infections. PMID:27058519

  12. Molecular dynamics modelling of mechanical properties of polymers for adaptive aerospace structures

    NASA Astrophysics Data System (ADS)

    Papanikolaou, Michail; Drikakis, Dimitris; Asproulis, Nikolaos

    2015-02-01

    The features of adaptive structures depend on the properties of the supporting materials. For example, morphing wing structures require wing skin materials, such as rubbers that can withstand the forces imposed by the internal mechanism while maintaining the required aerodynamic properties of the aircraft. In this study, Molecular Dynamics and Minimization simulations are being used to establish well-equilibrated models of Ethylene-Propylene-Diene Monomer (EPDM) elastomer systems and investigate their mechanical properties.

  13. Identification and synthesis of macrolide pheromones of the grain beetle Oryzaephilus surinamensis and the frog Spinomantis aglavei.

    PubMed

    Hötling, Susann; Haberlag, Birte; Tamm, Matthias; Collatz, Jana; Mack, Patrick; Steidle, Johannes L M; Vences, Miguel; Schulz, Stefan

    2014-03-10

    Macrolide lactones, the so called cucujolides derived from unsaturated fatty acids, are aggregation pheromones of cucujid grain beetles. Thirty years ago, Oehlschlarger et al. showed that (3Z,6Z)-dodeca-3,6-dien-11-olide (4) and the respective 12-olide (7) attract the sawtoothed grain beetle Oryzaephilus surinamensis, whereas (5Z,8Z,13R)-tetradeca-5,8-dien-13-olide (5) increases the response synergistically. The frass of this beetle is attractive for its parasitoid Cephalonomia tarsalis, which potentially can be used for pest control. A GC/MS analysis of attractive frass showed the presence of 5, together with an unknown isomer. Cucujolide V was tentatively identified also in the femoral glands, pheromone-releasing structures, of the Madagascan mantelline frog Spinomantis aglavei. Therefore, a new route to synthesize doubly unsaturated macrolides allowing the flexible attachment of the side chain was developed. A straightforward method to obtain Z configured macrolides involves ring-closing alkyne metathesis (RCAM) followed by Lindlar-catalyzed hydrogenation. This methodology was extended to homoconjugated diene macrolides by using RCAM after introduction of one Z configured double bond in the precursor by Wittig reaction. A tungsten benzylidyne complex was used as the catalyst in the RCAM reaction, which afforded the products in high yield at room temperature. With the synthetic material at hand, the unknown isomer was identified as the new natural product (5Z,8Z,12R)-tetradeca-5,8-dien-12-olide, cucujolide X (8). Furthermore, the route also allowed the synthesis of cucujolide V in good yield. The natural products were identified by the synthesis of enantiomerically pure or enriched material and gas chromatography on chiral phases. The new macrolide (R)-8 proved to be biologically active, attracting female O. surinamensis, but no males. The synthetic material allowed the identification of (R)-5 in both the beetle and the frog. PMID:24523150

  14. Seismic evidence for hyper-stretched crust and mantle exhumation offshore Vietnam.

    NASA Astrophysics Data System (ADS)

    Savva, D.; Meresse, F.; Pubellier, M.; Chamot-Rooke, N.; Franke, D.; Steuer, S.; Sapin, F.; Auxietre, J. L.

    2012-04-01

    The Phu Khan basin is one of the sub-basins opened during the rifting of the South China Sea during the Eocene. The basin is located against the East-Vietnam Boundary Fault (EVBF) to the west and the oceanic crust to the east. Good quality seismic lines allow us to observe structures which highlight the rifting history of the South China Sea margin and the processes of crustal boudinage. A Moho rise is the prominent feature of the Central part of the basin. The mantle is shallowest in the center of the basin and at places is directly in contact with the sediments, via a large low-angle detachment fault which separates several crustal blocks. The axis of the Moho rise is roughly parallel to the South China Sea propagator direction. As a consequence, the upper and lower crusts are strongly extended by large crustal boudins. The network of normal fault is dense in the upper crust and propagates into the lower crust occasionally. However, the lower crust seems to be missing at some places. At the apex of the Moho rise, several indicators of fluids circulations have been observed, including volcanic edifices and gas escapes features. The seismic facies just above this Moho rise looks poorly stratified and might be affected by a certain degree of metamorphism. Three stages of extension are clearly identifiable, with age constrained by wells calibration of the horizons: the oldest rift sequence is identified from basement to Oligocene horizons; a second from Oligocene to Mid Miocene (15.5 Ma), and a third from Mid-Miocene to Upper Miocene (10.5 Ma). These three rifts have been formed with at least two directions of extension, a first which is North-South and a second NW - SE The well imaged 15.5 Ma horizon is tilted, as well as part of the subsequent in-filling which is fan-shaped. These are in turn sealed by the 10.5Ma unconformity. Although tectonic activity appears diachronous from north to south, we suggest that cessation of rifting and opening did not occur before 12

  15. The Symbiotic Performance of Chickpea Rhizobia Can Be Improved by Additional Copies of the clpB Chaperone Gene.

    PubMed

    Paço, Ana; Brígido, Clarisse; Alexandre, Ana; Mateos, Pedro F; Oliveira, Solange

    2016-01-01

    The ClpB chaperone is known to be involved in bacterial stress response. Moreover, recent studies suggest that this protein has also a role in the chickpea-rhizobia symbiosis. In order to improve both stress tolerance and symbiotic performance of a chickpea microsymbiont, the Mesorhizobium mediterraneum UPM-Ca36T strain was genetically transformed with pPHU231 containing an extra-copy of the clpB gene. To investigate if the clpB-transformed strain displays an improved stress tolerance, bacterial growth was evaluated under heat and acid stress conditions. In addition, the effect of the extra-copies of the clpB gene in the symbiotic performance was evaluated using plant growth assays (hydroponic and pot trials). The clpB-transformed strain is more tolerant to heat shock than the strain transformed with pPHU231, supporting the involvement of ClpB in rhizobia heat shock tolerance. Both plant growth assays showed that ClpB has an important role in chickpea-rhizobia symbiosis. The nodulation kinetics analysis showed a higher rate of nodule appearance with the clpB-transformed strain. This strain also induced a greater number of nodules and, more notably, its symbiotic effectiveness increased ~60% at pH5 and 83% at pH7, compared to the wild-type strain. Furthermore, a higher frequency of root hair curling was also observed in plants inoculated with the clpB-transformed strain, compared to the wild-type strain. The superior root hair curling induction, nodulation ability and symbiotic effectiveness of the clpB-transformed strain may be explained by an increased expression of symbiosis genes. Indeed, higher transcript levels of the nodulation genes nodA and nodC (~3 folds) were detected in the clpB-transformed strain. The improvement of rhizobia by addition of extra-copies of the clpB gene may be a promising strategy to obtain strains with enhanced stress tolerance and symbiotic effectiveness, thus contributing to their success as crop inoculants, particularly under

  16. Gastroprotective effects of new diterpenoid derivatives from Azorella cuatrecasasii Mathias & Constance obtained using a β-cyclodextrin complex with microbial and chemical transformations.

    PubMed

    Sepúlveda, Beatriz; Quispe, Cristina; Simirgiotis, Mario; García-Beltrán, Olimpo; Areche, Carlos

    2016-07-15

    Mulinane diterpenoids isolated from Azorella species have displayed gastroprotective effects in animal models. In this study we have transformed the main constituent, mulin-11,13-dien-20 oic acid from this plant using the filamentous fungus Mucor plumbeus and a β-cyclodextrin inclusion complex and we have obtained two main products with good yields (33% and 15% for compound 4 and 5, respectively) for further preparation of semisynthetic derivatives to evaluate their gastroprotective effects. In addition, one of the compounds isolated from Azorella cuatrecasasii was new (9-epi-13α-hydroxymulinene 1). Six new derivatives 4a-4c and 5a-5c were then prepared by simple chemical transformations. The structures of all compounds were elucidated by spectroscopic means based on 1D and 2D-NMR techniques. Some 8 diterpenes were evaluated for their gastroprotective effects in the ethanol/HCl-induced ulcer model in mice at 20mg/kg. The highest gastroprotective activity was shown by 7α,16-dihydroxymulin-11,13-dien-20-oic acid 5, which was higher than the reference drug lansoprazole, while 16-hydroxymulin-11,13-dien-20-oic acid 4 was as active as lansoprazole. PMID:27262597

  17. Application of an enyne metathesis/Diels-Alder cycloaddition sequence: a new versatile approach to the syntheses of C-aryl glycosides and spiro-C-aryl glycosides.

    PubMed

    Subrahmanyam, Ayyagari V; Palanichamy, Kalanidhi; Kaliappan, Krishna P

    2010-07-26

    An efficient approach for the synthesis of a variety of C-aryl and spiro-C-aryl glycosides is described. This diversity-oriented strategy employed here relies on a sequential enyne metathesis to generate the 1,3-diene moiety and Diels-Alder reaction with different dienophiles followed by aromatisation. Whereas cross-enyne metathesis with ethylene gas is used to install the 1,3-diene moiety at the anomeric centre for the synthesis of C-aryl glycosides, an intramolecular enyne metathesis on the sugar enyne is performed to generate the 1,3-diene moiety for the synthesis of spiro-C-aryl glycosides. Efforts to extend this strategy to the synthesis of the core structure of natural C-aryl glycoside gilvocarcin are also described. A combination of both C-aryl and spiro-C-aryl glycosides in the same moiety to combine the features thereof has also been accomplished. A tandem enyne metathesis/Diels-Alder reaction/aromatisation has also been attempted to directly access the C-aryl glycosides in one pot albeit in low yield. PMID:20549721

  18. Solvothermal syntheses and characterizations of three new holmium selenidostannates(iv): a rare example of adamantane-like [Sn4Se10](4-) selenidostannate(iv) with lanthanide complexes.

    PubMed

    Xiao, Hong-Ping; Zhou, Jian; Wang, Xiao-Li; Zou, Hua-Hong; Zhao, Rong-Qing; Xiao, Hong

    2014-08-28

    Three new holmium selenidostannates(iv), [Ho(dap)4]2[Sn2Se6]Cl2 (, dap = diaminopropane), {[Ho(dien)2]2(μ2-OH)2}[Sn2Se6] (, dien = diethylenetriamine), and [Ho2(tepa)2(μ2-OH)2Cl2]2[Sn4Se10]·4H2O (, tepa = tetraethylenepentamine), have been solvothermally synthesized and structurally characterized. consists of two mononuclear [Ho(dap)4](3+) complex cations, one [Sn2Se6](4-) anion built up from two [SnSe4] tetrahedra sharing a common edge, and two Cl(-) ions. consists of one binuclear holmium(iii) complex {[Ho(dien)2]2(μ2-OH)2}(4+) cation and one dimeric [Sn2Se6](4-) anion. is composed of rare binuclear holmium(iii) complex [Ho2(tepa)2(μ2-OH)2Cl2](2+) cations, adamantane-like [Sn4Se10](4-) and free water molecules. Although a few chalcogenidostannates(iv) with lanthanide(iii) complex cations acting as counterions have been reported, their anions are strongly dominated by the dimeric [Sn2Se6](4-) moieties. represents a rare example of an adamantane-like [Sn4Se10](4-) selenidostannate with lanthanide complexes as counterions. The optical properties of have been investigated by UV-vis spectroscopy. PMID:24986054

  19. The Effect of Acetaminophen on Oxidative Modification of Low-Density Lipoproteins in Hypercholesterolemic Rabbits

    PubMed Central

    Özsoy, Meral Baş; Pabuçcuoğlu, Aysun

    2007-01-01

    Oxidative modification of low-density lipoproteins (LDL) contributes to the pathology of atherosclerosis. Antioxidants may protect LDL against oxidative modification. Acetaminophen, a widely used analgesic and antipyretic agent, has significant antioxidant properties. However, there is little evidence to suggest that acetaminophen acts as an antioxidant for LDL oxidation in vivo. In this study, we investigated the in vivo effect of acetaminophen on LDL oxidation in hypercholesterolemic rabbits. The oxidative modification of LDL was identified by conjugated dienes and thiobarbituric acid-reactive substances (TBARS). In the cholesterol group which rabbits were fed a diet contained 1% g cholesterol for 8 weeks, TBARS contents and conjugated diene levels in the plasma and isolated LDL samples significantly increased compared with the control rabbits (p<0.05). However, in the cholesterol + acetaminophen group, the TBARS contents and conjugated diene levels were significantly lower than that of the cholesterol group (p<0.05). The results from in vitro studies also demonstrated that the LDL isolated from serum was oxidized by Cu++ ions and this oxidation reduced in the presence of acetaminophen. The reduced oxidative modification of LDL by acetaminophen may be of therapeutic value in preventing the development and progression of atherosclerosis. PMID:18392104

  20. Stimulatory effects of starfish sapogenins (Asterias amurensis and Lethasterias nanimensis chelifera) on molluscan heart (Spisula sachalinensis).

    PubMed

    Gorshkov, B A; Kapustina, I I; Kicha, A A; Aminin, D L; Gorshkova, I A

    1998-08-01

    Sapogenins from the starfish Asterias amurensis and Lethasterias nanimensis chelifera, 5 alpha-pregn-9(11)-ene-3 beta,6 alpha-diol-20-one, 5 alpha-cholest-9(11)-ene-3 beta,6 alpha-diol-23-one, 5 alpha-cholesta-9(11),24(25)-diene-3 beta,6 alpha-diol-23-one, (20E)-5 alpha-cholesta-9(11),20(22)-diene-3 beta,6 alpha-diol-23-one and 24 zeta-methyl-5 alpha-cholesta-9(11),20(22)-diene-3 beta,6 alpha-diol-23-one, stimulated the contractile force of the heart of the mollusk Spisula sachalinensis at concentration of 5 x 10(-5) M. Ouabain, a specific inhibitor of Na+,K(+)-ATPase, at concentration of 5 x 10(-5) M had no effect on this physiological model. Starfish sapogenins of the cholestane series moderately inhibited rat brain cortex Na+,K(+)-ATPase and decreased Ca2+ influx into Ehrlich carcinoma cells. In contrast, pregnane asterogenin asterone did not inhibit Na+,K(+)-ATPase and increased the influx of Ca2+ into cells. These effects were not the result of cell membrane damage, because none of the compounds tested have hemolytic activity. PMID:9827037

  1. [Lipid peroxidation and the system of antioxidant protection in rats following a 13-day space flight on the Kosmos-1887 biosatellite].

    PubMed

    Markin, A A; Delenian, N V

    1992-01-01

    After a 13-day space mission, in the rats flown on Cosmos-1887 biosatellite the parameters of lipid peroxidation and antioxidant defense system--the contents of diene conjugates, malonic dialdehyde, Schiff bases, tocopherol, total antioxidant activity (in blood plasma only), antioxidant enzyme activity (in tissues only)--superoxide dismutase, catalase, glutathio peroxidase, glutathio reductase have been measured in the blood plasma, myocardium, skeletal muscles and liver. The liver level of diene conjugates, Schiff bases and tocopherol decreased, and an activity of superoxide dismutase and catalase increased. In the skeletal muscles there was an elevation of diene conjugate contents followed by the decreases in malonic dialdehyde and superoxide dismutase activity. In rat myocardium, superoxide dismutase activity and tocopherol levels increased significantly. In the blood plasma the levels of tocopherol, malonic dialdehyde and total antioxidant activity were elevated. It is concluded that the observed changes in lipid peroxidation developed probably in response to an effect of the last dynamic stage of space flight and during re-adapting to the Earth environments. PMID:1299445

  2. Two novel selenidostannates from mixed structure-directing systems: the large ten-membered ring of [Sn3Se4] semicubes and the 3D [Sn4Se9]n(2n-) with multi-channels.

    PubMed

    Du, Cheng-Feng; Shen, Nan-Nan; Li, Jian-Rong; Hao, Min-Ting; Wang, Zi; Cheng, Chu-Chu; Huang, Xiao-Ying

    2016-06-21

    Ionothermal syntheses, characterization and properties of two selenidostannate compounds with two- or three-dimensional (D) skeletons by utilizing the synergistic structure-directing effects of the ionic liquid (IL) [Bmmim]Cl (Bmmim = 1-butyl-2,3-dimethylimidazolium) and in-situ generated metal-amine complexes (MACs), namely, 2D-(Bmmim)2[Ni(teta)(en)][Sn3Se7]2 (1, teta = triethylenetetramine, en = ethylenediamine) and 3D-(Bmmim)1.5(dienH)0.5Ni(dien)2[Sn4Se9]2 (2, dien = diethylenetriamine) are presented. Single-crystal X-ray diffraction analyses revealed that compound 1 possesses a lamellar anionic [Sn3Se7]n(2n-) structure comprising a large ten-membered ring with a window size of 24.85 × 13.38 Å when considering the [Sn3Se4] semicube as a member. While 2 features a 3D [Sn4Se9]n(2n-) framework with orthogonally intersecting channels where the three different types of cations are filled. The successful isolation of these two compounds demonstrated again that the mixed SDA strategy is promising for the synthesis of novel crystalline selenidostannates. PMID:27193871

  3. LC-MS N-alkylamide profiling of an ethanolic Anacyclus pyrethrum root extract.

    PubMed

    Boonen, Jente; Sharma, Vikas; Dixit, Vinod Kumar; Burvenich, Christian; De Spiegeleer, Bart

    2012-11-01

    An N-alkylamide profiling from an ethanolic Anacyclus pyrethrum DC. root extract was performed using a gradient reversed phase high performance liquid chromatography/UV/electrospray-ionization ion-trap mass spectrometry (HPLC/UV/ESI-MS) method on an embedded polar column. MS1 and MS2 fragmentation data were used for identification purposes while UV was used for quantification. Thirteen N-alkylamides (five N-isobutylamides, three N-methyl isobutylamides, four tyramides and one 2-phenylethylamide) were detected. Six of them, identified as undeca-2E,4E-diene-8,10-diynoic acid isobutylamide, undeca-2E,4E-diene-8,10-diynoic acid N-methyl isobutylamide, tetradeca-2E,4E-diene-8,10-diynoic acid tyramide, deca-2E,4E-dienoic acid N-methyl isobutylamide, tetradeca-2E,4E,XE/Z-trienoic acid tyramide and tetradeca-2E,4E,XE/Z,YE/Z-tetraenoic isobutylamide, are novel compounds which have never been reported before from Anacyclus pyrethrum. PMID:23047251

  4. Organic functional group transformations in water at elevated temperature and pressure: Reversibility, reactivity, and mechanisms

    NASA Astrophysics Data System (ADS)

    Shipp, Jessie; Gould, Ian R.; Herckes, Pierre; Shock, Everett L.; Williams, Lynda B.; Hartnett, Hilairy E.

    2013-03-01

    Many transformation reactions involving hydrocarbons occur in the presence of H2O in hydrothermal systems and deep sedimentary systems. We investigate these reactions using laboratory-based organic chemistry experiments at high temperature and pressure (300 °C and 100 MPa). Organic functional group transformation reactions using model organic compounds based on cyclohexane with one or two methyl groups provided regio- and stereochemical markers that yield information about reversibility and reaction mechanisms. We found rapidly reversible interconversion between alkanes, alkenes, dienes, alcohols, ketones, and enones. The alkane-to-ketone reactions were not only completely reversible, but also exhibited such extensive reversibility that any of the functional groups along the reaction path (alcohol, ketone, and even the diene) could be used as the reactant and form all the other groups as products. There was also a propensity for these ring-based structures to dehydrogenate; presumably from the alkene, through a diene, to an aromatic ring. The product suites provide strong evidence that water behaved as a reactant and the various functional groups showed differing degrees of reactivity. Mechanistically-revealing products indicated reaction mechanisms that involve carbon-centered cation intermediates. This work therefore demonstrates that a wide range of organic compound types can be generated by abiotic reactions at hydrothermal conditions.

  5. The Stone-Wales transformation: from fullerenes to graphite, from radiation damage to heat capacity.

    PubMed

    Heggie, M I; Haffenden, G L; Latham, C D; Trevethan, T

    2016-09-13

    The Stone-Wales (SW) transformation, or carbon-bond rotation, has been fundamental to understanding fullerene growth and stability, and ab initio calculations show it to be a high-energy process. The nature and topology of the fullerene energy landscape shows how the Ih-C60 must be the final product, if SW transformations are fast enough, and various mechanisms for their catalysis have been proposed. We review SW transformations in fullerenes and then discuss the analogous transformation in graphite, where they form the Dienes defect, originally posited to be a transition state in the direct exchange of a bonded atom pair. On the basis of density functional theory calculations in the local density approximation, we propose that non-equilibrium concentrations of the Dienes defect arising from displacing radiation are rapidly healed by point defects and that equilibrium concentrations of Dienes defects are responsible for the divergent ultra-high-temperature heat capacity of graphite.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'. PMID:27501968

  6. Five dimeric thiogermanates with transition metal complexes of multidentate chelating amines: Syntheses, structures, magnetism and photoluminescence

    NASA Astrophysics Data System (ADS)

    Liu, Guang-Ning; Guo, Guo-Cong; Wang, Ming-Sheng; Cai, Li-Zhen; Huang, Jin-Shun

    2010-11-01

    Five new thiogermanates, [Ni II(dien) 2] 2(Ge 2S 6) (dien = diethylenetriamine) ( 1), [Ni II(dien) 2](H 2pipe)(Ge 2S 6) (pipe = piperazine) ( 2), {[Mn II(tren)] 2( μ2-Ge 2S 6)} (tren = N,N,N-tris(2-aminoethyl)amine) ( 3) and {[M II(tepa)] 2( μ2-Ge 2S 6)} (M = Mn ( 4a), Ni ( 4b); tepa = tetraethylenepentamine), have been obtained solvothermally in the presence of tri-(L 3), tetra-(L 4) and penta-dentate (L 5) chelating amines and transition metal (TM) ions. Single-crystal X-ray diffraction analyses show that compounds 1- 2 are comprised of discrete (Ge 2S 6) 4- anions and TM complex (TMC) cations, while compounds 3- 4b are composed of each dimeric (Ge 2S 6) 4- anion bridging two TMC cations via TM-S bonds to form a neutral molecule. Notably, two interesting in situ metal/ligand reactions were observed in the solvothermal syntheses of 2 and 3. The present compounds exhibit wide optical gap ranging from 2.94 to 3.39 eV and photoluminescence with the emission maxima occurring around 440 ( 1, 2, 3 and 4b) and 489 nm ( 4a). Magnetic measurements show the presence of weak antiferromagnetic interactions between magnetic centers in the five compounds.

  7. Inflammatory response, neutrophil activation, and free radical production after acute myocardial infarction: effect of thrombolytic treatment.

    PubMed Central

    Bell, D; Jackson, M; Nicoll, J J; Millar, A; Dawes, J; Muir, A L

    1990-01-01

    Activated neutrophils releasing proteolytic enzymes and oxygen free radicals have been implicated in extending myocardial injury after myocardial infarction. Neutrophil elastase was used as a marker of neutrophil activation and the non-peroxide diene conjugate of linoleic acid was used as an indicator of free radical activity in 32 patients after acute myocardial infarction; 17 were treated by intravenous thrombolysis. Patients with acute myocardial infarction had higher plasma concentrations of neutrophil elastase and the non-peroxide diene conjugated isomer of linoleic acid than normal volunteers or patients with stable ischaemic heart disease. Patients treated by thrombolysis had an early peak of neutrophil elastase at eight hours while those who had not been treated by thrombolysis showed a later peak 40 hours after infarction. The plasma concentration of non-peroxide conjugated diene of linoleic acid was highest 16 hours after the infarction irrespective of treatment by thrombolysis. Quantitative imaging with single photon emission tomography showed decreased uptake of indium-111 labelled neutrophils in the infarcted myocardium (as judged from technetium-99m pyrophosphate) in those who had received thrombolysis, suggesting a decreased inflammatory response. The results indicate increased neutrophil activation and free radical production after myocardial infarction; they also suggest that thrombolysis does not amplify the inflammatory response and may indeed suppress it. Images PMID:2317413

  8. Androstene-17-thioketals. 1st communication: glucocorticoid receptor binding, antiproliferative and antiinflammatory activities of some novel 20-thiasteroids (androstene-17-thioketals).

    PubMed

    Wojnar, R J; Varma, R K; Free, C A; Millonig, R C; Karanewsky, D; Lutsky, B N

    1986-12-01

    The unique replacements of the alpha-hydroxyl and beta-ketol groups of corticoids at C17 with selected, simple alkylthio or (2-fluoroalkyl)thio groups resulted in the structurally novel steroids, C17-alkylthioketals of 9 alpha-fluoro-11 beta-hydroxy-androsta-1,4-diene-3,17-dione. The described androstene-17-thioketals (20-thiasteroids) had high affinities for the glucocorticoid receptor protein of rat liver cytosol. Most were more potent than triamcinolone acetonide, a clinically moderately potent corticoid, in antiproliferative and antiinflammatory activities in mice. Specifically, (11 beta, 17 alpha)-17-(ethylthio)-9 alpha-fluoro-11 beta-hydroxy-17-(methylthio) androsta-1,4-dien-3-one (tipredane, SQ 27,239) and (11 beta, 17 alpha)-17-(ethylthio)-9 alpha-fluoro-17-[2-(fluoroethyl)thio] - 11 beta - hydroxy-androsta-1,4-dien-3-one (SQ 28,300), topically applied, were as potent as halcinonide, a clinically highly potent corticoid, in inhibition of croton oil-induced edema in the mouse. It is suggested that both thiasteroids could be moderately to highly potent topical antiinflammatory agents in man. PMID:3494458

  9. [THE INFLUENCE OF NANODISPERSE CERIUM DIOXIDE ON ONTOGENETIC CHANGES OF ANTIOXIDANT SYSTEM IN THE MUCOSA OF THE STOMACH AND COLON IN RATS].

    PubMed

    Iefimenko, O Yu; Savchenko, I O; Falalyeyeva, T M; Beregova, T V; Zholobak, N M; Shcherbakov, O B; Malyukin, Yu V; Spivak, M Ya

    2015-01-01

    It was established that with age the content of lipid peroxidation products increased in the mucosa of the stomach: Diene conjugates by 30%, products which react to thiobarbituric acid by 285% and Schif bases by 181%. Nanodisperse cerium dioxide (NCD) reduced the content of lipid peroxidation in the gastric mucosa in old rats: Diene conjugates by 43 %, products which react to thiobarbituric acid by 51% and Schif bases by 44% relative to the control group of rats given age. Similarly, it was established that the content of Diene conjugates increased by 40%, products which react to thiobarbituric acid by 114% and Schif bases by 132% in the mucosa of the colon of old rats. NDC significant reduced the content of products which react to thiobarbituric acid by 69% and Schyf basics by 132%. In the stomach superoxide dismutase (by 43%) and catalase activity (by 24%) decreases with age, while in the colon superoxide dismutase activity increases (by 43%). In the colon NCD significant decreased superoxide dismutase (by 34%) and catalase activity (by 21%) relative to controls. Thus, the NDC restores lipid peroxidation in the gastric mucosa and colon, in which develops oxidative stress with age. PMID:26495735

  10. Diterpene constituents of leaves from Juniperus brevifolia.

    PubMed

    Seca, Ana M L; Silva, Artur M S; Bazzocchi, Isabel L; Jimenez, Ignacio A

    2008-01-01

    The dichloromethane extract from leaves of Juniperus brevifolia, through chromatographic fractionations yield six compounds: 3beta-hydroxy-abieta-8,11,13-trien-7-one, 18-hydroxy-sandaracopimara-8(14),15-dien-7-one, sandaracopimara-8(14),15-dien-18-yl formate; and the first examples of sandaracopimaranes and abieta-8,11,13-triene diterpenoids with a large aliphatic chain on C-18, abieta-8,11,13-trien-18-yl hexadecanoate, 7-oxoabieta-8,11,13-trien-18-yl hexadecanoate, sandaracopimara-8(14),15-dien-18-yl hexadecanoate. Moreover fifteen known compounds were also isolated, some of them for the first time identified on Juniperus genus. The compound abieta-8,11,13-trien-18-yl formate is reported for the first time as a natural product. All the structures were established by spectroscopic methods. 2D NMR techniques have allowed the revision of certain previously reported (13)C NMR assignments. Studies on the isolated new compounds showed those possessing a diterpenol ester of a long-chain fatty acid present lipophilicity very distinct from other diterpenoid compounds. PMID:17854850

  11. Comparative sex pherome biosynthesis in Thaumetopoea pityocampa and T. processionea: a rationale for the phenotypic variation in the sex pherome within the genus Thaumetopoea.

    PubMed

    Villorbina, G; Rodríguez, S; Camps, F; Fabriàs, G

    2003-02-01

    The female sex pheromones of the Mediterranean processionary moths (Thaumetopoea sp.) are conjugated dienes or enynes of 16 carbon atoms with the unsaturations located at C11 and C13. To investigate the biochemical basis of this phenotypic variation, the biosynthetic pathway of T. processionea sex pheromone, a diene acetate, has been elucidated and compared to that reported for the enyne-producing species T. pityocampa. Mass labeling experiments showed that T. processionea sex pheromone is biosynthesized from palmitic acid, by subsequent (Z)-11 and (Z)-13 desaturations and final reduction and acetylation. The Pheromone Biosynthesis Activating Neuropeptide (PBAN) activates this biosynthetic pathway downstream of the dienoate intermediate. When either 11-hexadecynoic acid or (Z)-13-hexadecen-11-ynoic acid were administered to T. processionea, this species was able to produce the enyne sex pheromone of T. pityocampa upon PBAN stimulation. In contrast, T. pityocampa does not produce either 11-hexadecynyl acetate or (Z,Z)-11,13-hexadecadienyl acetate, despite having the corresponding precursors in the pheromone gland. However, both acetates are detected after administration of the corresponding alcohols. These overall results suggest that the absence of delta(11) acetylenase and the existence of an enynoate specific reductase in the diene and enyne-producing Thaumetopeae, respectively, account for the different sex pheromones produced by the two groups. PMID:12535674

  12. One pot synthesis of biologically active pregnane derivatives, their single crystal structures, spectroscopic characterization and theoretical calculations

    NASA Astrophysics Data System (ADS)

    Sethi, Arun; Bhatia, Akriti; Bhatia, Gitika; Shrivastava, Atul; Prakash, Rohit

    2013-11-01

    One pot allylic oxidation of 3β-acetoxypregna-5,16-diene-20-one (2) and nucleophilic addition at C-16 position of 3β-hydroxypregna-5,16-diene-20-one (3) yielded 3β-acetoxypregna-5,16-diene-7,20-dione (4) and 3β-hydroxy-16α-(5'-hydroxypentyloxy)-pregn-5-ene-20-one (5) respectively in high yield. A detailed theoretical study supported by X-ray analysis of compounds 4 and 5 has been carried out. Conformational analysis of compounds 4 and 5 was done with the help of crystal structure, which crystallize out in orthorhombic form having P212121 space group. Structural characterization of compounds 4 and 5 was done with the aid of 1H, 13C NMR, IR, UV, ESI-MS and ESI-HRMS. The molecular geometries and vibrational frequencies for compounds 4 and 5 in the ground state were calculated using the Density functional theory (DFT) with 6-31G(d,p) basis set and compared with experimental data. 1H and 13C nuclear magnetic resonance magnetic shifts of 4 and 5 were calculated using GIAO method and compared with the experimental data. UV-Vis spectra of both the compounds were recorded and electronic properties such as HOMO-LUMO energies were calculated by time dependent TD-DFT approach. The compounds were screened for their anti-hyperlipidemic and anti-oxidant activity.

  13. Antimicrobial evaluation of clerodane diterpenes from Polyalthia longifolia var. pendula.

    PubMed

    Sashidhara, Koneni V; Singh, Suriya P; Shukla, P K

    2009-03-01

    Phytochemical investigation of the ethanolic extract of leaves of Polyalthia longifolia var. pendula has led to the isolation of seven clerodane diterpenoids and five alkaloids. (-)-14, 15-bisnor-3, 11E-kolavadien-13-one (1), (-)-16-oxocleroda-3,13(14)E-dien-15-oic acid (2), (-)-16alpha-hydroxycleroda-3,13 (14)Z-dien-15,16-olide (3), (+)-(4-->2)-abeo-16(R/S)-2, 13Z-kolavadien-15, 16-olide-3-al (4), (-)-3beta, 16beta-dihydroxycleroda-4(18), 13(14)Z-dien-15,16-olide (5), (-)-3, 12E-kolavadien-15-oic acid-16-al (6), (-)-labd-13E-en-8-ol-15-oic acid (7), liriodenine (8), (-)-anonaine (9), (+)-isoboldine (10), (-)-asimilobine (11) and hordenine (12) have been isolated. This is the first report of 1, 6 and 10 from this plant species while 12 is reported for first time from this genus. Clerodane derivatives 1-7 were evaluated for their antimicrobial activity. Diterpene 3 was found to be most potent agent with MIC value of 6.25 microg/mL against Staphylococcus aureus and Sporothrix schenckii. PMID:19413108

  14. Les carcinomes de la thyroïde: profils épidémiologique, clinique et thérapeutique, à propos de 102 cas

    PubMed Central

    Touati, Mohamed Mliha; Aljalil, Abdelfettah; Darouassi, Youssef; Chihani, Mehdi; Lahkim, Mohammed; Fihri, Jawad Al Fassi; Bouaity, Brahim; Ammar, Haddou

    2015-01-01

    Les carcinomes thyroïdiens sont des tumeurs malignes assez rares, représentant 1% des cancers. Ils sont généralement de bon pronostic, et présentent des aspects cliniques et évolutifs variés selon leur origine histologique. Notre travail est une étude rétrospective portant sur 102 cas de carcinomes de la thyroïde, colligés sur un nombre total de 811 gestes chirurgicaux thyroïdiens, au service d'oto-rhino-laryngologie et de chirurgie cervico-faciale de l'hôpital militaire Avicenne de Marrakech, sur une période de 8 ans, allant de janvier 2006 à décembre 2013. Les carcinomes thyroïdiens atteignent le sujet jeune avant l’âge de 50 ans, en particulier le sexe féminin. La tendance dans les pays en voie de développement, comme dans le monde entier est en croissance continue, ceci peut être expliqué par l'amélioration des outils d'imagerie et des moyens diagnostiques cytologiques et anatomo-pathologiques. PMID:26405495

  15. Structural characterization of some oxalato-bridged copper(II) and nickel(II) complexes

    NASA Astrophysics Data System (ADS)

    Mautner, Franz A.; Louka, Febee R.; Massoud, Salah S.

    2009-03-01

    A new series of dinuclear oxalato-bridged copper(II) and nickel(II) complexes derived from tridentate amines: [Cu 2(Medpt) 2(μ-C 2O 4)](ClO 4) 2 ( 1), [Cu 2(pmedien) 2(μ-C 2O 4)](ClO 4) 2 ( 2), [Cu 2(DPA) 2(μ-C 2O 4)(ClO 4) 2]·2H 2O (3), and [Ni 2(Et 2dien) 2(μ-C 2O 4)(H 2O) 2](ClO 4) 2·2H 2O ( 4) (C 2O 42- = oxalate dianion, Medpt = 3,3'-diamino- N-methyldipropylmine, pmedien = N, N, N', N'', N''-pentamethyldiethylenetriamine, DPA = di(2-pyridylmethyl)amine and Et 2dien = N, N-diethyldiethylenetriamine) were synthesized and structurally characterized by X-ray crystallography. The spectral and structural characterizations of these complexes are reported. In this series, structures consist of the C 2O 42- bridging the two M(II) centers in a bis-bidentate bonding mode. The Cu 2+ centers are coordinated to the tridentate amines Medpt or pmedien in distorted SP geometry in 1 and 2, respectively, with the ClO 4- groups as counter ions. In the other two complexes, distorted octahedral geometries were achieved by the three nitrogen donors of the DPA and by an oxygen atom from coordinated perchlorate ion in 3 and by the Et 2dien and one water molecule in 4.

  16. [The effect of hypoxia and of subsequent baro-oxygenation on the function of the microsomal oxidation system in the rat liver].

    PubMed

    Shchugaleĭ, V S; Ananian, A A; Miliutina, N P; Sadekova, S I

    1992-01-01

    The increase of cytochrome P-450 by 34% and its catalytic activity with substrate amidopyrine by 57% as compared with control has been shown under hypoxia (0.029 MPa, 1 h). Hyperoxia (0.2 MPa, 1 h) increases the metabolism of amidopyrine by 148%, benzo[a]pyrene by 158% and aniline by 114% and consecutive affection of hypoxia and hyperoxia--by 247, 45 and 138% correspondingly at fixed cytochrome P-450 amount in both series. The amount of diene conjugates and Schiff's bases under hypoxia increases by 40 and 69% correspondingly, the activity of SOD and catalase decreases by 25 and 23%. The activity of hyperoxia raises the diene conjugate content by 19% at all this SOD activity increases by 95%. Consecutive affection of hypoxia and hyperoxia increases the level of diene conjugates and Schiff's bases by 26 and 23% correspondingly, without changing SOD and catalase activity. The relative microsomal viscosity of lipid layer and zones of enzyme-lipid contacts decreased by 20 and 24% under hypoxia, but under hyperoxia and consecutive affection and hypoxia and hyperoxia it increases by 29-28% and 56-40% correspondingly. PMID:1303102

  17. Antitubercular sterols from Thalia multiflora Horkel ex Koernicke.

    PubMed

    Gutierrez-Lugo, Maria-Teresa; Wang, Yuehong; Franzblau, Scott G; Suarez, Enrique; Timmermann, Barbara N

    2005-10-01

    Bioassay guided isolation of an antitubercular extract of the aerial parts of Thalia multiflora led to the isolation of nine stigmast-5-ene and stigmasta-5,22-dien steroids, four isorhamnetin and quercetin flavonoid glycosides, two ceramides, an indole alkaloid and two simple phenolic compounds. Stigmast-5-en-3beta-ol-7-one (2), stigmast-4-ene-6beta-ol-3-one (3), stigmast-5,22-dien-3beta-ol-7-one (7) and stigmast-4,22-dien-6beta-ol-3-one (8) were found to be the most active compounds with MIC values of 1.98 +/- 0.02, 4.2 +/- 0.17, 1.0 +/- 0.06 and 2.2 +/- 0.3 microg/mL, respectively. Compounds 2, 3, 7 and 8 were not cytotoxic to Vero cells at 102 microg/mL. This investigation constitutes the first report of a chemical study of a species of the genus Thalia. PMID:16261518

  18. The metabolism of carbohydrates and lipid peroxidation in lead-exposed workers.

    PubMed

    Kasperczyk, Aleksandra; Dobrakowski, Michal; Ostałowska, Alina; Zalejska-Fiolka, Jolanta; Birkner, Ewa

    2015-12-01

    The present study was undertaken to estimate the effect of occupational exposure to lead on the blood concentration of glucose and several enzymes involved in glycolysis, the citric acid cycle, and the pentose phosphate pathway. To estimate the degree of lipid peroxidation, the concentrations of conjugated dienes were determined. The examined group included 145 healthy male employees of lead-zinc works. Taking into account the mean blood lead levels, the examined group was divided into two subgroups. The control group was composed of 36 healthy male administrative workers. The markers of lead exposure were significantly elevated in both subgroups when compared with the controls. There were no significant changes in fasting glucose concentration and fructose-1,6-bisphosphate aldolase activity in the study population. The concentration of conjugated dienes was significantly higher in both subgroups, whereas the activity of malate dehydrogenase was significantly higher only in the group with higher exposure. The activities of lactate dehydrogenase and sorbitol dehydrogenase were significantly decreased in the examined subgroups. The activity of glucose-6-phosphate dehydrogenase decreased significantly in the group with higher exposure and could be the cause of the elevated concentrations of conjugated dienes. It is possible to conclude that lead interferes with carbohydrate metabolism, but compensatory mechanisms seem to be efficient, as glucose homeostasis in lead-exposed workers was not disturbed. PMID:23833244

  19. Herbicidal and Cytotoxic Constituents from Aralia armata (Wall.) Seem.

    PubMed

    Miao, Hui; Sun, Yongyan; Yuan, Yunfei; Zhao, Huanhuan; Wu, Jiao; Zhang, Weiyun; Zhou, Lijuan

    2016-04-01

    Two new triterpenoids, 3β-hydroxyoleana-11,13(18)-diene-28,30-dioic acid (1) and 3-oxooleana-11,13(18)-diene-28,30-dioic acid (2), one novel triterpenoid glycoside, 3β-O-(6'-O-methyl-β-d-glucuronopyranosyl)oleana-11,13(18)-dien-28-oic acid (3) along with six known compounds (4 - 9) were isolated from the stem bark of Aralia armata (Wall.) Seem. Their structures were elucidated through extensive spectroscopic methods. The herbicidal activities of these compounds against Bidens pilosa L., an invasive weed in P. R. China, were evaluated. Compounds 3, 5, and 6 exhibited more significant herbicidal activities on B. pilosa than the positive-control pendimethalin. Their possible use as herbicidal chemicals or model compounds deserved more attention. The effects of compounds 1 - 9 on Spodoptera litura cultured cell line Sl-1 cell proliferation and its morphology were also evaluated. The results indicated that compounds 1 - 5 affected Sl-1 cell proliferation. Compound 3 showed more obvious proliferation inhibition activities on Sl-1 cell than the positive-control rotenone. With regard to the effect on morphology, compound 2 significantly changed Sl-1 cell, resulting in cell blebbing and vacuole forming. Triterpenoids aremedicinally and agriculturally important, and cytotoxicity of the three new compounds 1 - 3 deserved further studies. PMID:26948515

  20. Source location and characterization of volatile organic compound emissions at a petrochemical plant in Kaohsiung, Taiwan.

    PubMed

    Chen, Chin-Liang; Fang, Hung Yuan; Shu, Chi-Min

    2005-10-01

    This paper elucidated a novel approach to locating volatile organic compound (VOC) emission sources and characterizing their VOCs by database and contour plotting. The target of this survey was a petrochemical plant in Linyan, Kaohsiung County, Taiwan. Samples were taken with canisters from 25 sites inside this plant, twice per season, and analyzed by gas chromatography-mass spectrometry. The survey covered 1 whole year. By consolidated into a database, the data could be readily retrieved, statistically analyzed, and clearly presented in both table and graph forms. It followed from the cross-analysis of the database that the abundant types of VOCs were alkanes, alkenes/dienes, and aromatics, all of which accounted for 99% of total VOCs. By contour plotting, the emission sources for alkanes, aromatics, and alkenes/ dienes were successfully located. Through statistical analysis, the database could provide the range and 90% confidence interval of each species from each emission source. Both alkanes and alkene/dienes came from tank farm and naphtha cracking units and were mainly composed of C3-C5 members. Regarding aromatics, benzene, toluene, and xylenes were the primary species; they were emitted from tank farm, aromatic units, and xylene units. PMID:16295274