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Sample records for terephthalic acid synthesis

  1. Synthesis and Verification of Biobased Terephthalic Acid from Furfural

    Science.gov (United States)

    Tachibana, Yuya; Kimura, Saori; Kasuya, Ken-Ichi

    2015-02-01

    Exploiting biomass as an alternative to petrochemicals for the production of commodity plastics is vitally important if we are to become a more sustainable society. Here, we report a synthetic route for the production of terephthalic acid (TPA), the monomer of the widely used thermoplastic polymer poly(ethylene terephthalate) (PET), from the biomass-derived starting material furfural. Biobased furfural was oxidised and dehydrated to give maleic anhydride, which was further reacted with biobased furan to give its Diels-Alder (DA) adduct. The dehydration of the DA adduct gave phthalic anhydride, which was converted via phthalic acid and dipotassium phthalate to TPA. The biobased carbon content of the TPA was measured by accelerator mass spectroscopy and the TPA was found to be made of 100% biobased carbon.

  2. Effects of synthesis conditions on chemical structures and physical properties of copolyesters from lactic acid, ethylene glycol and dimethyl terephthalate

    Directory of Open Access Journals (Sweden)

    2009-07-01

    Full Text Available Lactic acid/ethylene terephthalate copolyesters were synthesized by the standard melt polycondensation of lactic acid (L, ethylene glycol (EG and dimethyl-terephthalate (DMT. Effects of reaction temperatures and types of catalysts on the structures and properties of the copolymers were examined. In addition, feasibility of promoting the copolymerization process by a novel synthesis step of using thermo-stabilizers was investigated. The results show that a reaction temperature of higher than 180°C is necessary to produce copolymers with appreciable molecular weight. However, degradation was observed when the reaction temperature is higher than 220°C. Triphenyl phosphate (TPP shows promising results as a potential thermo-stabilizer to minimize this problem. It was found that Sb2O3 and Tin(II octoate are most effective among 4 types of catalysts employed in this study. 1H-NMR results indicate that copolymers have a random microstructure composed mainly of single L units alternately linked with ET blocks at various sequential lengths. The longer ET sequence in the chain structure leads to the increase in melting temperature of the copolymer. TGA results show that the resulting copolymers possessed greater thermal stability than commercially-available aliphatic PLA, as a result of the inclusion of T (terephthalate units in the chain structure.

  3. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural

    OpenAIRE

    Pacheco, Joshua J.; Davis, Mark E

    2014-01-01

    Current, plant-based polyethylene terephthalate (PET) is produced from biomass-derived ethylene glycol [the terephthalic acid (PTA) used is not from biomass]. To have a 100% biomass-derived PET, PTA must be produced from biomass. Here, pathways for the production of renewable PTA, using Diels-Alder reactions between ethylene and oxidized derivatives of 5-hydroxymethylfurfural, a biomass-derived chemical, are reported. These pathways are enabled by new catalytic chemistry that may provide rout...

  4. Synthesis and luminescent properties of Eu(III) complexes of 2-thienyltrifluoroacetonate, terephthalic acid and trioctylphosphine oxide

    International Nuclear Information System (INIS)

    This work reports the synthesis and luminescent properties of the terephthalic acid (TPA) and europium(III) (Eu(III)) with 2-thienyltrifluoroacetonate (HTTA) and trioctylphosphine oxide (TPPO), in the solid state. The new complexes Eu(TPA)(TTA)(TPPO)2 and Eu2(TPA)(TTA)4(TPPO)4 were characterized by elemental analysis, infrared spectroscopy, scanning electronic microscopy and thermal stability analysis. The complexes Eu(TPA)(TTA)(TPPO)2 and Eu2(TPA)(TTA)4(TPPO)4 present higher thermal stability than Eu(TTA)3(TPPO)2 does. And the formation of the binuclear/polynuclear structure of the complexes appears to be responsible for the enhancement of the thermal stability. The emission spectra present narrow emission bands that arise from the 5D0-7F J (J = 0-4) transition of the Eu3+ ion. The spectral data of the complexes Eu(TPA)(TTA)(TPPO)2 and Eu2(TPA)(TTA)4(TPPO)4 show only one sharp peak in the region of the 5D0-7F0 transition indicating that only one Eu(III) ion species is present in each sample. In addition, the luminescence decay curves of the complexes Eu(TPA)(TTA)(TPPO)2 and Eu2(TPA)(TTA)4(TPPO)4 fit a single-exponential decay law. The values of quantum efficiencies of the emitting 5D0 level for the complexes Eu(TPA)(TTA)(TPPO)2 and Eu2(TPA)(TTA)4(TPPO)4 are 26.4 and 25.6%, respectively

  5. Catalytic and Mechanistic Studies of Polyethylene Terephthalate Synthesis

    OpenAIRE

    Toufaili, Faissal-Ali El-

    2006-01-01

    Polyethylene terephthalate synthesis by polycondensation of its monomer bis-hydroxy ethylene terephthalate was investigated. Two catalysts were studied; a homogenous one based on antimony and a heterogeneous one based on hydrotalcite. Two methods were applied to monitor the reaction progress; thermogravimetry and calorimetry. The reaction was performed in bulk under non-isothermal conditions in the melt phase. 10 mg of monomer/catalyst mixtures were heated at a constant heating rate in the ra...

  6. Synthesis and characterizations of degradable aliphatic-aromatic copolyesters from lactic acid, dimethyl terephthalate and diol: Effects of diol type and monomer feed ratio

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available Lactic acid-based aliphatic/aromatic copolyesters are synthesized to incorporate the degradability of polylactic acid and good mechanical properties of aromatic species by using polycondensation of lactic acid (LA, dimethyl terephthalate (DMT, and various diols. Effects of diol lengths and comonomer feed ratios on structure and properties of the resulting copolymers are investigated. Three types of diols with different methylene lengths are employed, i.e., ethylene glycol (EG, 1,3-propanediol (PD and 1,4-butanediol (BD. LA/DMT/diol feed ratios of 2:1:2, 1:1:2, and 1:2:4 are used in each diol system. It is found that types of the diols play an important role in the properties of the copolyester, where an increase in diol length results in an increase in the copolymers molecular weight, and a decrease in Tg, Tm and crystallinity, when a constant monomer feed ratio is employed. Monomer feed ratio also has a significant effect on properties of the copolymers, where an increase in the aromatic content leads to formation of copolymers with higher molecular weight, longer aromatic block sequence and high aromatic to aliphatic ratio in the chain structure. These, in turn, lead to an increase in Tg, Tm, crystallinity and thermal stability of the copolymer samples, and a reduction in their solubility.

  7. Degradation of terephthalic acid by a newly isolated strain of Arthrobacter sp.0574

    Scientific Electronic Library Online (English)

    Yi-Mei, Zhang; Yao-Qun, Sun; Zhi-Jiang, Wang; Jie, Zhang.

    Full Text Available Terephthalic acid is an important industrial chemical but its production typically generates 3-10 tons of wastewater, which is a significant source of pollution. Although recent research has shown that terephthalic acid can be degraded by physical and chemical methods, these methods are complex and [...] expensive. Microbial degradation of terephthalic acid is a popular alternative because it is environmentally friendly. We isolated a Gram-positive strain capable of growing aerobically on terephthalic acid as the sole carbon and energy source. It was identified as Arthrobacter sp. by 16S rDNA sequencing and its physiological and biochemical characteristics. For terephthalic acid degradation, the optimal temperature of the resting cells was 30 °C, optimal shaking speed was 150 rpm, the most suitable pH was 7.0, and the ability to degrade terephthalic acid was inhibited by concentrations of terephthalic acid above 10 g/L.

  8. The Glycolysis of Poly(ethylene terephthalate) Waste: Lewis Acidic Ionic Liquids as High Efficient Catalysts

    OpenAIRE

    Mi Lin Zhang; Xue Feng Bai; Qun Feng Yue; Lin Fei Xiao

    2013-01-01

    Poly(ethlyene terephthalate) waste from a local market was depolymerized by ethylene glycol (EG) in the presence of Lewis acidic ionic liquids [Bmim]ZnCl3 and the qualitative analysis showed that bis(hydroxyethyl) terephthalate was the main product. Compared with ionic liquid [Bmim]Cl, the Lewis acidic ionic liquids showed highly catalytic activity in the glycolysis of poly(ethylene terephthalate) PET. Significantly, the conversion of PET and the yield of bis(hydroxyethyl) terephthalate were ...

  9. Sequential pyrolysis of plastic to recover polystyrene HCL and terephthalic acid

    Science.gov (United States)

    Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

    1995-01-01

    A process of pyrolyzing plastic waste feed streams containing polyvinyl chloride, polyethylene terephthalate, polystyrene and polyethylene to recover polystyrene HCl and terephthalic acid comprising: heating the plastic waste feed stream to a first temperature; adding an acid or base catalyst on an oxide or carbonate support; heating the plastic waste feed stream to pyrolyze polyethylene terephthalate and polyvinyl chloride; separating terephthalic acid or HCl; heating to a second temperature to pyrolyze polystyrene; separating styrene; heating the waste feed stream to a third temperature to pyrolyze polyethylene; and separating hydrocarbons.

  10. Synthesis Dibenzyl Terephthalate Through Depolimerization of Poly(ethylene terephthalate as Alternative of Waste Plastics Recycling.

    Directory of Open Access Journals (Sweden)

    Dyah Anitasari

    2005-04-01

    Full Text Available Synthesis dibenzyl terephathalate were done through PET degradation by refluxing in benzyl alcohol at 145oC temperature for 20, 24, and 28 hours in the presence of zinc acetate catalyst. The result of degradation was purified by recristalization in methanol and then melting point (mp, FTIR, 1H NMR spectra, and TLC spot were determined. The melting point of product degradation for 28 hours was 98-99 oC. Based FTIR spectra known that compunds of product degradation have OH, C=O, C-O, CH, monosubstituted benzene, disubstituted benzene groups, while on 1H NMR spectra showed chemical shift at 8.2 ppm (s, 10 H of monosubtituted benzene, 7.5 ppm (s, 9 H consist of 4 H disubstituted benzene and 5 H of aromatic benzyl alcohol, 5.4 ppm (s, 1 H from OH benzyl alcohol, 4.8 ppm (s, 4 H of methylene, and 2.9 ppm (s, 7 H of other traces. The single spot of TLC plate indicated that product degradation for 28 hours might be a single compund. Based these characterization concluded that compound of product degradation was dibenzyl terephthalate contains benzyl alcohol and other traces.

  11. Chemical Recycling of Pop Bottles: The Synthesis of Dibenzyl Terephthalate from the Plastic Polyethylene Terephthalate

    Science.gov (United States)

    Donahue, Craig J.; Exline, Jennifer A.; Warner, Cynthia

    2003-01-01

    A laboratory procedure involving the chemical recycling of the plastic polyethylene terephthalate (PET or PETE) from 2-L pop bottles is described. A transesterification reaction is employed to depolymerize PET. At atmospheric pressure in refluxing benzyl alcohol in the presence of a catalyst, PET is converted to dibenzyl terephthalate in moderate yields. This procedure models an industrial process that involves the transesterification reaction of PET with methanol at high temperature and pressure, conditions not normally accessible in an undergraduate laboratory, to yield dimethyl terephthalate and ethylene glycol. A second method of preparing dibenzyl terephthalate starting with terephthaloyl chloride is also described. The diester from these two approaches is characterized using melting points, TLC, and IR and NMR spectroscopy. This experiment has been used in a general chemistry sequence that has sections on organic chemistry and polymer chemistry, but is also well suited for an introductory organic chemistry laboratory course or a polymer chemistry laboratory course. This lab experiment is part of a larger effort to develop a general chemistry sequence for engineering students using the theme of chemistry and the automobile. Student results are presented.

  12. New Titanium-Based Catalysts for the Synthesis of Poly(ethylene terephthalate)

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Youngkeun; Yoon, Seungwoong; Hwang, Yongtaek; Song, Bogeun [Honam Petrochemical Corporation, Daejeon (Korea, Republic of)

    2012-10-15

    Poly(ethylene terephthalate) (PET) is a polymer with relatively low cost and high performance, which is widely used in various applications such as bottles, textile fibers, films and engineering plastics for automobiles and electric industries. Commercial catalysts used for synthesis of PET are in general antimony (Sb) compounds. Antimony(III) oxide, antimony(III) acetate and antimony(III) glycolate are used as a catalyst in 95% of PET manufacturing industries worldwide. The few organoantimony compounds that have been identified in environmental and biological samples are all in the form of methylated Sb-species. The Sb trace element is extremely toxic to mammals, and interferes with embryonic and fetal development, also, carcinogenic to humans. In addition to being found in drinking water, food packaging and soft-drink bottles. According to the World Health Organization (WHO), Sb species concentration lower than 20 ppb are acceptable for drinking water. According to a recent study, in 14 brands of bottled water from Canada, Sb concentrations increased on average 19% during 6 months storage at room temperature, but 48 brands of water from 11 European countries increased on average 90% under identical conditions. Therefore, a very important challenge for polyester catalysis is to come-up with a new Sb-free catalysts with low environmental impact. Intensive efforts have been made to find other stable and more environmental friendly non-antimony catalysts, such as those based on titanium. Titanium-based catalysts have been known for many years and actually are used for polybutylene terephthalate (PBT) and polypropylene terephthalate (PPT) production, however, polycondensation (PC) of PET manufacture is not well studied in literature. To date, only few esterification processes have been applied for the synthesis of PET by titanium catalysts. Herein, we report an efficient synthesis characterization and polymerization of PET for a series of new nontoxic organotitanium catalyst. Titanium metal has strong activity in polyesterification and forms stable complex with heteroatom-containing ligands (Scheme 1). These properties of titanium have been used advantageously in simple methods of syntheses and production of inexpensive metal catalyst. The high activity and selectivity of titanium-containing catalysts, their good solubility, and the absence of acidic effluent, which causes corrosion, are the reasons why these catalysts are frequently used in industry.

  13. New Titanium-Based Catalysts for the Synthesis of Poly(ethylene terephthalate)

    International Nuclear Information System (INIS)

    Poly(ethylene terephthalate) (PET) is a polymer with relatively low cost and high performance, which is widely used in various applications such as bottles, textile fibers, films and engineering plastics for automobiles and electric industries. Commercial catalysts used for synthesis of PET are in general antimony (Sb) compounds. Antimony(III) oxide, antimony(III) acetate and antimony(III) glycolate are used as a catalyst in 95% of PET manufacturing industries worldwide. The few organoantimony compounds that have been identified in environmental and biological samples are all in the form of methylated Sb-species. The Sb trace element is extremely toxic to mammals, and interferes with embryonic and fetal development, also, carcinogenic to humans. In addition to being found in drinking water, food packaging and soft-drink bottles. According to the World Health Organization (WHO), Sb species concentration lower than 20 ppb are acceptable for drinking water. According to a recent study, in 14 brands of bottled water from Canada, Sb concentrations increased on average 19% during 6 months storage at room temperature, but 48 brands of water from 11 European countries increased on average 90% under identical conditions. Therefore, a very important challenge for polyester catalysis is to come-up with a new Sb-free catalysts with low environmental impact. Intensive efforts have been made to find other stable and more environmental friendly non-antimony catalysts, such as those based on titanium. Titanium-based catalysts have been known for many years and actually are used for polybutylene terephthalate (PBT) and polypropylene terephthalate (PPT) production, however, polycondensation (PC) of PET manufacture is not well studied in literature. To date, only few esterification processes have been applied for the synthesis of PET by titanium catalysts. Herein, we report an efficient synthesis characterization and polymerization of PET for a series of new nontoxic organotitanium catalyst. Titanium metal has strong activity in polyesterification and forms stable complex with heteroatom-containing ligands (Scheme 1). These properties of titanium have been used advantageously in simple methods of syntheses and production of inexpensive metal catalyst. The high activity and selectivity of titanium-containing catalysts, their good solubility, and the absence of acidic effluent, which causes corrosion, are the reasons why these catalysts are frequently used in industry

  14. A New Esterase from Thermobifida halotolerans Hydrolyses Polyethylene Terephthalate (PET) and Polylactic Acid (PLA)

    OpenAIRE

    Georg Steinkellner; Karl Gruber; Helmut Schwab; Guebitz, Georg M; Rosario Diaz Rodriguez; Annemarie Marold; Sabine Zitzenbacher; Anita Dellacher; Katrin Greimel; Doris Ribitsch; Enrique Herrero Acero

    2012-01-01

    A new esterase from Thermobifida halotolerans (Thh_Est) was cloned and expressed in E. coli and investigated for surface hydrolysis of polylactic acid (PLA) and polyethylene terephthalate (PET). Thh_Est is a member of the serine hydrolases superfamily containing the -GxSxG- motif with 85–87% homology to an esterase from T. alba, to an acetylxylan esterase from T. fusca and to various Thermobifida cutinases. Thh_Est hydrolyzed the PET model substrate bis(benzoyloxyethyl)terephthalate and PET r...

  15. A New Esterase from Thermobifida halotolerans Hydrolyses Polyethylene Terephthalate (PET and Polylactic Acid (PLA

    Directory of Open Access Journals (Sweden)

    Georg Steinkellner

    2012-02-01

    Full Text Available A new esterase from Thermobifida halotolerans (Thh_Est was cloned and expressed in E. coli and investigated for surface hydrolysis of polylactic acid (PLA and polyethylene terephthalate (PET. Thh_Est is a member of the serine hydrolases superfamily containing the -GxSxG- motif with 85–87% homology to an esterase from T. alba, to an acetylxylan esterase from T. fusca and to various Thermobifida cutinases. Thh_Est hydrolyzed the PET model substrate bis(benzoyloxyethylterephthalate and PET releasing terephthalic acid and mono-(2-hydroxyethyl terephthalate in comparable amounts (19.8 and 21.5 mmol/mol of enzyme while no higher oligomers like bis-(2-hydroxyethyl terephthalate were detected. Similarly, PLA was hydrolyzed as indicated by the release of lactic acid. Enzymatic surface hydrolysis of PET and PLA led to a strong hydrophilicity increase, as quantified with a WCA decrease from 90.8° and 75.5° to 50.4° and to a complete spread of the water drop on the surface, respectively.

  16. The Glycolysis of Poly(ethylene terephthalate Waste: Lewis Acidic Ionic Liquids as High Efficient Catalysts

    Directory of Open Access Journals (Sweden)

    Mi Lin Zhang

    2013-11-01

    Full Text Available Poly(ethlyene terephthalate waste from a local market was depolymerized by ethylene glycol (EG in the presence of Lewis acidic ionic liquids [Bmim]ZnCl3 and the qualitative analysis showed that bis(hydroxyethyl terephthalate was the main product. Compared with ionic liquid [Bmim]Cl, the Lewis acidic ionic liquids showed highly catalytic activity in the glycolysis of poly(ethylene terephthalate PET. Significantly, the conversion of PET and the yield of bis(hydroxyethyl terephthalate were achieved at 100% and 83.8% with low catalyst ([Bmim]ZnCl3 loading (0.16 wt %. Investigation also showed that the catalytic activity of [Bmim]ZnCl3 was higher than that of [Bmim]MnCl3. Catalyst [Bmim]ZnCl3 can be reused up to five times and 1H-NMR results show that the recovered catalyst is similar to the fresh one. A mechanism of the glycolysis of PET catalyzed by [Bmim]ZnCl3 was proposed.

  17. 1-Phenyl-3-(quinolin-5-yl)urea as a host for distinction of phthalic acid and terephthalic ac

    Indian Academy of Sciences (India)

    Dipjyoti Kalita; Jubaraj B Baruah

    2013-03-01

    Co-crystals of 1-phenyl-3-(quinolin-5-yl)urea (1) with terephthalic acid, adipic acid; and salts of 1 with phthalic acid, -toluenesulphonic acids are prepared and structurally characterized. The reaction of phthalic acid and -toluenesulphonic acid resulted in protonation of the host 1, whereas the terephthalic acid and adipic acid interact with 1, led to cocrystals with the host 1 through hydrogen bond interactions. The hydrogen bonds that appears in the urea taps of the host molecules 1 are lost while formation of salts; in such cases anions interacts with the urea portion of the host, while in the co-crystals the hydrogen bonded urea taps are retained. The salts are yellow in colour while the co-crystals are colourless; thereby the positional isomer phthalic acid can be distinguished from the terephthalic acid.

  18. Polyesters production from the mixture of phthalic acid, terephthalic and glycerol

    International Nuclear Information System (INIS)

    Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

  19. Preparation of polymer blends from glycerol, fumaric acid and of poly(ethylene terephthalate) (PET) recycled

    International Nuclear Information System (INIS)

    Polymer blends based on recycled poly(ethylene terephthalate) (PET) and poly(glycerol fumarate) polyesters were prepared in different PET concentrations. The PET powder was dispersed during the poly(glycerol fumarate) synthesis at 260 deg C. The resulting blends were characterized by X-ray diffraction. The thermal stability of the materials was evaluated by thermogravimetric analysis and differential scanning calorimetry. The morphology was studies by scanning electron microscopy. The blends were clearly immiscible. The possibility of (interfacial) compatibilization of the PET domains, caused by transesterification reactions between PET and glycerol were discussed. (author)

  20. The influence of Copolimers Acrylic Acid onto Poli(Etilene Terephthalate)woven fabric

    International Nuclear Information System (INIS)

    To improve suitability of wearing poli etilene terephthalate (PET) wovenfabric, it need to enhance the ability in absorbing of water vapour. For theabove reason acrylic acid (AA) has been grafted onto PET wovenfabric(PET-g-AA). Fourier Transform Infrared (FT-IR) data show that poly(acrylic acid) have grafted onto PET woven fabric. Thermal propertiesobtained from DSC (Differential Scanning Calorimeter) measurements of PET-g-AA show that the grafting does not affect bulk properties of PET. Thedecrease of the tensile strength had occurred to PET-g-MMA, however it ratherinfluenced by the reaction time than the initial concentration of acrylicacid. (author)

  1. Application of several advanced oxidation processes for the destruction of terephthalic acid (TPA)

    International Nuclear Information System (INIS)

    Terephthalic acid (TPA) is widely applied as a raw material in making polyester fiber, polyethylene terephthalate (PET) bottles, polyester films, etc. TPA is toxic and is known to act as endocrine disruptor. TPA wastewater is traditionally treated by biological process and this study aims to evaluate the effectiveness of several advanced oxidation processes on TPA removal. The oxidation processes studied were: UV-TiO2, UV-H2O2, UV-H2O2-Fe, O3, O3/Fe, O3/TiO2, UV-O3-H2O2-Fe and UV-O3-H2O2-Fe-TiO2. The results indicate that the time required for the complete destruction of 50 ppm of TPA can be minimized from 10 h using UV-TiO2 system, to less than 10 min by UV-H2O2-Fe-O3 system. Some of the likely organic intermediates identified during TPA destruction include, benzoquinone, benzene, maleic acid and oxalic acid. Possible destruction pathway of TPA has been proposed. TPA degradation by various systems was also analyzed based on the reaction kinetics and operating costs

  2. Application of several advanced oxidation processes for the destruction of terephthalic acid (TPA)

    Energy Technology Data Exchange (ETDEWEB)

    Thiruvenkatachari, Ramesh [Department of Chemical Engineering, Sunchon National University, 315 Maegok Dong, Suncheon 540-742, Chonnam (Korea, Republic of); Kwon, Tae Ouk [Department of Chemical Engineering, Sunchon National University, 315 Maegok Dong, Suncheon 540-742, Chonnam (Korea, Republic of); Jun, Jung Chul [Department of Chemical Engineering, Sunchon National University, 315 Maegok Dong, Suncheon 540-742, Chonnam (Korea, Republic of); Balaji, Subramanian [Department of Chemical Engineering, Sunchon National University, 315 Maegok Dong, Suncheon 540-742, Chonnam (Korea, Republic of); Matheswaran, Manickam [Department of Chemical Engineering, Sunchon National University, 315 Maegok Dong, Suncheon 540-742, Chonnam (Korea, Republic of); Moon, Il Shik [Department of Chemical Engineering, Sunchon National University, 315 Maegok Dong, Suncheon 540-742, Chonnam (Korea, Republic of)]. E-mail: ismoon@sunchon.ac.kr

    2007-04-02

    Terephthalic acid (TPA) is widely applied as a raw material in making polyester fiber, polyethylene terephthalate (PET) bottles, polyester films, etc. TPA is toxic and is known to act as endocrine disruptor. TPA wastewater is traditionally treated by biological process and this study aims to evaluate the effectiveness of several advanced oxidation processes on TPA removal. The oxidation processes studied were: UV-TiO{sub 2}, UV-H{sub 2}O{sub 2}, UV-H{sub 2}O{sub 2}-Fe, O{sub 3}, O{sub 3}/Fe, O{sub 3}/TiO{sub 2}, UV-O{sub 3}-H{sub 2}O{sub 2}-Fe and UV-O{sub 3}-H{sub 2}O{sub 2}-Fe-TiO{sub 2}. The results indicate that the time required for the complete destruction of 50 ppm of TPA can be minimized from 10 h using UV-TiO{sub 2} system, to less than 10 min by UV-H{sub 2}O{sub 2}-Fe-O{sub 3} system. Some of the likely organic intermediates identified during TPA destruction include, benzoquinone, benzene, maleic acid and oxalic acid. Possible destruction pathway of TPA has been proposed. TPA degradation by various systems was also analyzed based on the reaction kinetics and operating costs.

  3. Effect of heat and solvent treatment on radiation grafting of acrylic acid to poly(ethylene terephthalate)

    International Nuclear Information System (INIS)

    Direct radiation graft polymerization of acrylic acid onto oriented poly(ethylene terephthalate) films and fibers subjected to thermal treatment and treated with structure-active solvents, such as dichloroethane and dioxane, was studied. Poly(ethylene terephthalate) films and fibers treated with the solvents were irradiated on a 60Co ?-source with doses 10-20 kGy, at dose rates 1-4 kGy/h. Based on the results of thermomechanical analysis, X-ray diffraction, sorption, and acrylic acid grafting, conclusions were drawn concerning the character of structural changes in poly(ethylene terephthalate) exposed to structure-active solvents. The physicochemical properties of the graft copolymers obtained were examined, including the resistance to ?-radiation

  4. Effect of oral administration of terephthalic acid on testicular functions of rats

    International Nuclear Information System (INIS)

    To investigate the toxic effect of terephthalic acid (TPA) on testicular functions of rats, male Sprague-Dawley rats were orally administered TPA in diet at the levels 0 (control), 0.2, 1 and 5% for 90 days. Testicular functions were assessed by histopathology, testicular sperm head counts, daily sperm production, sperm motility (measured by computer-assisted sperm analysis, CASA), biochemical indices (marker testicular enzymes), and serum testosterone. Oral feeding with terephthalic acid did not cause body and testes weight loss in TPA-treated groups. Histopathologically, damages of spermatogenic cells and Sertoli cells were observed by electron microscope, testicular sperm head counts, daily sperm production, and activities of sorbitol dehydrogenase (SDH) were decreased significantly in the 5% TPA group. The motility of spermatozoa was reduced significantly in all treated groups, which was correlated with administration doses. Serum testosterone concentrations were not declined in treated groups. In conclusion, TPA can cause impairment of testicular functions. The primary sites of action may be spermatogenic cells and Sertoli cells. The results of the present study provide first information of TPA on testicular functions in male rats

  5. Bimodal electricity generation and aromatic compounds removal from purified terephthalic acid plant wastewater in a microbial fuel cell.

    Science.gov (United States)

    Marashi, Seyed Kamran Foad; Kariminia, Hamid-Reza; Savizi, Iman Shahidi Pour

    2013-02-01

    Wastewater of purified terephthalic acid (PTA) from a petrochemical plant was examined in a membrane-less single chamber microbial fuel cell for the first time. Time course of voltage during the cell operation cycle had two steady phases, which refers to the fact that metabolism of microorganisms was shifted from highly to less biodegradable carbon sources. The produced power density was 31.8 mW m(-2) (normalized per cathode area) and the calculated coulombic efficiency was 2.05 % for a COD removal of 74 % during 21 days. The total removal rate of different pollutants in the PTA wastewater was observed in the following order: (acetic acid) > (benzoic acid) > (phthalic acid) > (terephthalic acid) > (p-toluic acid). The cyclic voltammetry results revealed that the electron transfer mechanism was dominated by mediators which were produced by bacteria. PMID:23076363

  6. ?-radiation-induced graft copolymerization of acrylic acid onto poly (ethylene terephthalate) films: A study by thermal analysis

    International Nuclear Information System (INIS)

    The grafting of acrylic acid onto poly (ethylene terephthalate) films with ? radiation was carried out. The effects of different parameters, such as the monomer concentration, inhibitor concentration, and irradiation dose, on the grafting yield were investigated. The grafting yield depended on these parameters, and its maximum value was obtained at a 1.5% inhibitor concentration and a 40%, monomer concentration. The obtained grafting films were characterized with water swelling measurements, differential scanning, calorimetry, and thermogravimetric analysis. The results of differential scanning calorimetry showed decreases in the heat capacity step and the glass-transition temperature with increasing grafting yield. The ability of poly (ethylene terephthalate) to crystallize and the size of the crystalline domains were affected by the grafting. The grafted poly(ethylene terephthalate) that was obtained was tested as an ion exchanger for copper, nickel, cobalt, and lead. The capacity of the grafted films for ion recovery was dependent on the grafting yield. (author)

  7. Preparation and characterization of polymer blends based on recycled PET and polyester derived by terephthalic acid

    International Nuclear Information System (INIS)

    Environmentally friendly materials, made from industrial waste, are being increasingly used as a solution to the growing amount of waste generated by society, but also as a cheaper alternative to replace conventional materials for use in construction. In this work were investigated the properties of polymer blends based on recycled PET and a polyester derived from terephthalic acid and glycerin, a co-product of biodiesel. The samples were characterized by XRD, TGA, DSC, FTIR and SEM. The polyester synthesized showed a degradation event near 300 deg C. The blends with higher ratio of PET showed thermal behavior similar to pure PET. The X-ray diffraction showed that the polymer blends are semicrystalline materials. The micrographs presents the presence of a smooth surface, indicating the possibility of miscibility between the arrays. Therefore, the blending makes possible the fabrication of low-cost materials with applications in several areas. (author)

  8. Assessing human exposure to phthalic acid and phthalate esters from mineral water stored in polyethylene terephthalate and glass bottles

    OpenAIRE

    Montuori, Paolo; Jover, Eric; Morgantini, Marcello; Bayona, Josep Maria; Triassi, Maria

    2008-01-01

    Abstract Abstract. Phthalic acid and phthalates esters present a growing interest due to a large use and to their potential toxicity. Polyethylene terephthalate (PET) and glass are both widely used materials for the bottling of drinking water. In this study, phthalic acid (PhA), bis(2-ethylhexyl) phthalate (DEHP), dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiisoBP) and dibutyl phthalate (DBP) were analyzed in a large pool of Italian bottled water sampl...

  9. Ultrafiltration membranes from waste polyethylene terephthalate and additives: synthesis and characterization

    Scientific Electronic Library Online (English)

    Smitha, Rajesh; Zagabathuni Venkata Panchakshari, Murthy.

    Full Text Available The synthesis and characterization of asymmetric ultrafiltration membranes from recycled polyethylene terephthalate (PET) and polyvinylpyrrolidone (PVP) is reported. PET is currently used in many applications, including the manufacture of bottles and tableware. Monomer extraction from waste PET is e [...] xpensive, and this process has not yet been successfully demonstrated on a viable scale. Hence, any method to recycle or regenerate PET once it has been used is of significant importance from scientific and environmental research viewpoints. Such a process would be a green alternative due to reduced raw monomer consumption and the additional benefit of reduced manufacturing costs. The membranes described here were prepared by a phase-inversion process, which involved casting a solution containing PET, m-cresol as solvent, and polyethylene glycol (PEG) of different molecular weights as additives. The membranes were characterized in terms of pure water permeability (PWP), molecular weight cut-off (MWCO), and flux and membrane morphology. The results show that the addition of PEG with high molecular weights leads to membranes with higher PWP. The presence of additives affects surface roughness and membrane morphology.

  10. Photocatalytic degradation of terephthalic acid on sulfated titania particles and identification of fluorescent intermediates.

    Science.gov (United States)

    Lin, Xuan Hao; Lee, Si Ni; Zhang, Wenlin; Li, Sam Fong Yau

    2016-02-13

    Terephthalic acid (TA) is toxic and known as an endocrine disruptor. In this paper, the photocatalytic degradation of TA using sulfated titanium dioxide SO4(2-)/TiO2 photocatalysts was investigated. The photocatalysts were prepared by sol-gel method and characterized by XRD, SEM, BET, ICP/MS and spectroscopic methods. Their activities were compared with bare TiO2 and Degussa P25. The effects of catalyst sulfur content, the initial TA concentration and pre-treatment conditions (O2, N2 or non-pretreated) were studied. O2 functions were also explored. Since there had been no comprehensive study of fluorescent intermediates reported yet, we investigated the intermediates and discovered 5 new intermediates (4 fluorescent and 1 non-fluorescent) which were identified by gas chromatography-mass spectrometry (GC/MS) and fluorescence spectroscopy. These intermediates are complementary to the previously identified carboxylic acid intermediates and might provide new insights to the mechanism of photocatalytic degradation of TA. Since TA is widely used as a probing molecule for photocatalytically generated (·)OH radicals, the ratios of fluorescent intermediates of TA degradation may provide new clues to the photocatalytic activity and mechanism. Based on the results obtained, the possible destruction pathway of TA is also proposed. PMID:26513565

  11. Synthesis and properties of poly(hexamethylene terephthalate)/multiwall carbon nanotubes nanocomposites

    OpenAIRE

    González Vidal, Nathalie; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián; Castell, Pere; Martínez, Maria Teresa

    2010-01-01

    Poly(hexamethylene terephthalate) (PHT)/carbon nanotubes (CNT) nanocomposites containing 1% and 3% (w/w) of filler were prepared by two procedures: in situ ring-opening polymerization of hexamethylene terephthalate cyclic oligomers in the presence of CNT and melt blending of PHT/CNT mixtures. Arc discharge multiwalled carbon nanotubes, both pristine (MWCNT) and hydroxyl functionalized (MWCNT-OH), were used. The objective was to evaluate the effect of preparation procedure, n...

  12. Chemical recycling of poly(ethylene terephthalate). Application to the synthesis of multiblock copolyesters

    OpenAIRE

    F. Malek; A. El Mejjatti; T. Harit; A. Riahi; R. Khiari; I. Bouabdallah

    2014-01-01

    The chemical recycling of the poly(ethylene terephthalate), (PET), has been successfully carried out by glycolysis in the presence of bis (2-hydroxyethyl) terephthalate (BHET) resulting in the formation of hydroxytelechelic oligomers. These oligomers were then treated with carboxytelechelic poly(?-caprolactone) oligomers of Mn = 2300 and Mn = 730 g•mol–1 molecular weight, in the absence or presence of the titanium tetrabutyloxide (Ti(OBu)4) as a catalyst to get multiblock copolyesters. The ch...

  13. Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ge-Fu; Wu, Peng; Wei, Qun-Shan; Lin, Jian-yi; Liu, Hai-Ning [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Gao, Yan-Li [China University of Geosciences, Wuhan 430074 (China)

    2010-08-15

    Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H{sub 2}) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m{sup 3} d, hydraulic retention time (HRT) of 6 h and temperature of (35 {+-} 1) C, when the pH value, alkalinity and oxidation-reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO{sub 3}/L, and -220 to -250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H{sub 2} volume content was estimated to be 48-53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H{sub 2} production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H{sub 2} production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H{sub 2} production from high-strength chemical wastewater. (author)

  14. Chemical recycling of poly(ethylene terephthalate. Application to the synthesis of multiblock copolyesters

    Directory of Open Access Journals (Sweden)

    F. Malek

    2014-08-01

    Full Text Available The chemical recycling of the poly(ethylene terephthalate, (PET, has been successfully carried out by glycolysis in the presence of bis (2-hydroxyethyl terephthalate (BHET resulting in the formation of hydroxytelechelic oligomers. These oligomers were then treated with carboxytelechelic poly(?-caprolactone oligomers of Mn = 2300 and Mn = 730 g•mol–1 molecular weight, in the absence or presence of the titanium tetrabutyloxide (Ti(OBu4 as a catalyst to get multiblock copolyesters. The chemical structure of the synthesized copolyesters was investigated by size exclusion chromatography (SEC and proton Nuclear Magnetic Resonance (1H NMR spectroscopy. Moreover the differential scanning calorimetry (DSC was used to explore their thermal properties. The ester-ester interchange reaction was observed between the two oligopolyesters, was studied and discussed in detail.

  15. High resolution solid state NMR in liquid. 4. 1H NMR study of terephthalic acid nano-particles

    International Nuclear Information System (INIS)

    High-resolution 1H NMR spectra of terephthalic acid (TPA) ultrafine particles (UFP's) were obtained under the conditions of rapid Brownian motion of UFP's in liquid CCl4 (UFP-NMR method). Six signals were resolved in the range of 6.85 to 7.65 ppm with respect to an tetramethylsilane. These were assigned to aromatic protons, even though only a single signal at 8.15 ppm was obtained from molecular dispersion of TPA in acetone. TPA-UFP dispersions were prepared by a vacuum evaporation technique combined with a cold matrix-isolation method. Particle sizes obtained were ca. 15 nm by a dynamic laser scattering method. The results from UFP-NMR method are discussed in conjunction with those from solid state 1H NMR via a CRAMPS method and with a conventional liquid state NMR of TPA. (author)

  16. Synthesis and Characterization of Cobalt/Palladium Multilayer Film and Nanodiscs on Polyethylene Terephthalate Substrate.

    Science.gov (United States)

    Li, Bihan; Liu, Xinming; Zhu, Mei; Wang, Zongbin; Adeyeye, A O; Choi, W K

    2015-06-01

    Cobalt/Palladium (Co/Pd) multilayer film and nanodisc samples were fabricated on polyethylene terephthalate (PET) substrates. The effects of surface roughness and grain size of PET substrate, the Co/Pd layer and the Au intermediate layer on the magnetic properties of these samples were investigated. We observed that the coercivity for Co/Pd films deposited directly on a smoother PET substrate is significantly smaller when compared with Co/Pd films deposited at the same time on Au buffer layer. The patterned Co/Pd nanodisc array exhibited a larger coercivity than the corresponding continuous film due to lower probability of finding nucleation sites in reduced film area. PMID:26369045

  17. Polyesters production from the mixture of phthalic acid, terephthalic and glycerol; Producao de poliesteres a partir da mistura de acido ftalico, tereftalico e glicerol

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M., E-mail: adrianaequfba@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Carvalho, R.F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Ambiental Urbana

    2010-07-01

    Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

  18. Atmospheric pressure synthesis of photoluminescent hybrid materials by sequential organometallic vapor infiltration into polyethylene terephthalate fibers

    Science.gov (United States)

    Akyildiz, Halil I.; Mousa, Moataz Bellah M.; Jur, Jesse S.

    2015-01-01

    Exposing a polymer to sequential organometallic vapor infiltration (SVI) under low pressure conditions can significantly modify the polymer's chemical, mechanical, and optical properties. We demonstrate that SVI of trimethylaluminum into polyethylene terephthalate (PET) can also proceed readily at atmospheric pressure, and at 60 °C the extent of reaction determined by mass uptake is independent of pressure between 2.5 Torr and 760 Torr. At 120 °C, however, the mass gain is 50% larger at 2.5 Torr relative to that at 760 Torr, indicating that the precursor diffusion in the chamber and fiber matrix decreases at higher source pressure. Mass gain decreases, in general, as the SVI process temperature increases both at 2.5 Torr and 760 Torr attributed to the faster reaction kinetics forming a barrier layer, which prevents further diffusion of the reactive species. The resulting PET/Al-Ox product shows high photoluminescence compared to untreated fibers. A physical mask on the polymer during infiltration at 760 Torr is replicated in the underlying polymer, producing an image in the polymer that is visible under UV illumination. Because of the reduced precursor diffusivity during exposure at 760 Torr, the image shows improved resolution compared to SVI performed under typical 2.5 Torr conditions.

  19. In situ synthesis of TiO2/polyethylene terephthalate hybrid nanocomposites at low temperature

    International Nuclear Information System (INIS)

    TiO2 nanoflowers were in situ grown on polyethylene terephthalate (PET) non-woven fabric by hydrolysis of TiCl4 in aqueous solution in the presence of nanocrystal cellulose grafted PET fabric (NCC-g-PET) at a low temperature of 70 °C. Nanocrystal cellulose (NCC) pre-grafted on PET fabric acted as hydrophilic substrate and morphology inducing agent to promote the nucleation and crystal growth of TiO2. Detailed information on the synthetic process was presented. The resulting samples were characterized using FE-SEM, EDS, ATR-IR, Raman microscopy, XRD and TG analysis. The photocatalytic activity of the samples was evaluated by the degradation of orange methyl under solar light. Characteristic results indicate that rutile TiO2 nanoflowers have grown abundantly on PET non-woven fabric, and the established hydrogen bonding strengthens the interfacial interaction between the inorganic particles and the polymeric substrates. The methyl orange decoloration test under natural solar light demonstrates that this TiO2/PET hybrid nanocomposites exhibit excellent self-cleaning performance which is expected to have a good potential for commercialization.

  20. Atmospheric pressure synthesis of photoluminescent hybrid materials by sequential organometallic vapor infiltration into polyethylene terephthalate fibers

    International Nuclear Information System (INIS)

    Exposing a polymer to sequential organometallic vapor infiltration (SVI) under low pressure conditions can significantly modify the polymer's chemical, mechanical, and optical properties. We demonstrate that SVI of trimethylaluminum into polyethylene terephthalate (PET) can also proceed readily at atmospheric pressure, and at 60?°C the extent of reaction determined by mass uptake is independent of pressure between 2.5?Torr and 760?Torr. At 120?°C, however, the mass gain is 50% larger at 2.5?Torr relative to that at 760?Torr, indicating that the precursor diffusion in the chamber and fiber matrix decreases at higher source pressure. Mass gain decreases, in general, as the SVI process temperature increases both at 2.5?Torr and 760?Torr attributed to the faster reaction kinetics forming a barrier layer, which prevents further diffusion of the reactive species. The resulting PET/Al-Ox product shows high photoluminescence compared to untreated fibers. A physical mask on the polymer during infiltration at 760?Torr is replicated in the underlying polymer, producing an image in the polymer that is visible under UV illumination. Because of the reduced precursor diffusivity during exposure at 760?Torr, the image shows improved resolution compared to SVI performed under typical 2.5?Torr conditions

  1. Visible light photocatalytic activity of rutile TiO2 fiber clusters in the degradation of terephthalic acid

    Science.gov (United States)

    Yener, H. Banu; Helvac?, ?erife ?.

    2015-09-01

    Rutile TiO2 nanoparticles, in different structural and morphological properties, were produced by the hydrolysis of titanium tetrachloride in a highly acidic reaction media at moderate temperatures without calcination. Their photocatalytic activities were investigated in the liquid-phase degradation of terephthalic acid under visible light illumination. The parameters, which are the concentration of the titanium tetrachloride solution (0.1-1 M) and reaction temperature (60-95 °C), effective on the properties of the particles, and their photocatalytic performances, were investigated. The XRD patterns indicated a pure rutile crystal structure at moderate temperatures without need of calcination. The FEGSEM images showed the formation of flower-, pinecone-, and sphere-like clusters consisting of interconnected nanofibers. The N2 adsorption-desorption isotherms pointed out the microporous structure of the clusters. Band gap energies were found to be varying between 3.02 and 3.08 eV due to the well-developed rutile crystallite structure. Systematic studies elucidated that the optimum reactant concentration and reaction temperature are 0.5 M TiCl4 and 95 °C, respectively. The rutile clusters synthesized at the optimum reaction conditions exhibited 99 % of the photocatalytic degradation of TPA under visible light illumination at shorter irradiation times compared with commercial P25 TiO2.

  2. Adsorption analysis of thin films of terephthalic acid on Au and Al studied by MIES, UPS and XPS

    Science.gov (United States)

    Marschewski, Marcel; Otto, Christian; Wegewitz, Lienhard; Höfft, Oliver; Schmidt, Andreas; Maus-Friedrichs, Wolfgang

    2015-06-01

    The adsorption behavior of thin films of terephthalic acid (TPA) evaporated on a gold surface as well as on an aluminum foil was studied. The orientation of the molecules was characterized by metastable induced electron spectroscopy (MIES) and ultraviolet photoelectron spectroscopy (UPS). To make sure that the evaporation of TPA is nondestructive, additional X-ray photoelectron spectroscopy (XPS) was performed. These measurements also exclude any radiation damage. TPA on the gold surface shows a well-ordered layer growth up to 7.5 nm. Since the MIES spectra show both the acid structure and the phenyl group, a flat-laying orientation is assumed. In contrast, the phenylic carbon structure could not be observed while evaporating TPA on the oxidized aluminum foil. The MIES/UPS spectra only show the COOH group. To exclude a random arrangement of the molecules we also performed low temperature measurements. It can be concluded from these measurements, in addition to the fact that the work function increases during the evaporation, that TPA has a perpendicular arrangement on the aluminum foil.

  3. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    1997-01-01

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures of 2,5-anhydrides and not the expected 2-acetamido-2-deoxy aldose phenylhydrazones. The acetylated phenylhydrazones were found to eliminate acetic acid when heated in aqueous ethanol and 1-phenylazoal...

  4. Dibutylphosphoric acid synthesis

    International Nuclear Information System (INIS)

    This work consists on the synthesis of dibutylphosphoric acis (DBP) by reaction of butanol with phosphorus pentoxid and on its separation by liquid-liquid extraction. It also deals with the characterization of DBP by some physicochemical analysis methods such as : chromatography, pH-metry and infrared and ultraviolet spectrophotometries. this study showed essentialy, that DBP can be formed in an appreciable amount (55%) when the reaction is realised with butanol/pentoxid molar ratio upper than 3 at temperature of 95 C

  5. Development of a bioprocess to convert PET derived terephthalic acid and biodiesel derived glycerol to medium chain length polyhydroxyalkanoate

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, Shane T.; Nikodinovic Runic, Jasmina; O' Connor, Kevin E. [University College Dublin (Ireland). School of Biomolecular and Biomedical Sciences; Kaminsky, Walter [Hamburg Univ. (Germany). Inst. of Technical and Macromolecular Chemistry; Woods, Trevor; Babu, Ramesh P. [Dublin Univ. (Ireland). Materials Ireland Polymer Research Center

    2012-08-15

    Sodium terephthalate (TA) produced from a PET pyrolysis product and waste glycerol (WG) from biodiesel manufacture were supplied to Pseudomonas putida GO16 in a fed-batch bioreactor. Six feeding strategies were employed by altering the sequence of TA and WG feeding. P. putida GO16 reached 8.70 g/l cell dry weight (CDW) and 2.61 g/l PHA in 48 h when grown on TA alone. When TA and WG were supplied in combination, biomass productivity (g/l/h) was increased between 1.3- and 1.7-fold and PHA productivity (g/l/h) was increased 1.8- to 2.2-fold compared to TA supplied alone. The monomer composition of the PHA accumulated from TA or WG was predominantly composed of 3-hydroxydecanoic acid. PHA monomers 3-hydroxytetradeeanoic acid and 3-hydroxytetradecenoic acid were not present in PHA accumulated from TA alone but were present when WG was supplied to the fermentation. When WG was either the sole carbon source or the predominant carbon source supplied to the fermentation the molecular weight of PHA accumulated was lower compared to PHA accumulated when TA was supplied as the sole substrate. Despite similarities in data for the properties of the polymers, PHAs produced with WG present in the PHA accumulation phase were tacky while PHA produced where TA was the sole carbon substrate in the polymer accumulation phase exhibited little or no tackiness at room temperature. The co-feeding of WG to fermentations allows for increased utilisation of TA. The order of feeding of WG and TA has an effect on TA utilisation and polymer properties. (orig.)

  6. Synthesis of new kojic acid based unnatural ?-amino acid derivatives.

    Science.gov (United States)

    Balakrishna, C; Payili, Nagaraju; Yennam, Satyanarayana; Uma Devi, P; Behera, Manoranjan

    2015-11-01

    An efficient method for the preparation of kojic acid based ?-amino acid derivatives by alkylation of glycinate schiff base with bromokojic acids have been described. Using this method, mono as well as di alkylated kojic acid-amino acid conjugates have been prepared. This is the first synthesis of C-linked kojic acid-amino acid conjugate where kojic acid is directly linked to amino acid through a C-C bond. PMID:26318994

  7. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    JØrgensen, Christel Thea

    1997-01-01

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures of 2,5-anhydrides and not the expected 2-acetamido-2-deoxy aldose phenylhydrazones. The acetylated phenylhydrazones were found to eliminate acetic acid when heated in aqueous ethanol and 1-phenylazoalkenes could be isolated by crystallisation. By this method the 17, 20, 23 and 25 were prepared from the phenylhydrazones of D-galactose, D-mannose, L-rhamnose and D-arabinose, respectively. The phenylazoalkenes were selectively reduced with sodium borohydride to give 2-deoxy aldose phenylhydrazones, which were hydrolysed to the corresponding 2-deoxy aldoses. Thus, 2-deoxy-D-lyxo-hexose (33), 2-deoxy-D-arabino-hexose (35), 2,6-dideoxy-L-arabino-hexose (37) and 2-deoxy-D-erythro-hexose (39) were prepared by this new method.Three new 2,3-aziridino-2,3-dideoxyhexonamides 43, 51 and 64 were prepared by a three step procedure from the readily available D-glucono-1,5-lactone, D-gulono-1,4-lactone and L-rhamnono-1,4-lactone, respectively. A 2,3-aziridino-2,3-dideoxypentonamide 70 was also prepared from D-glucono-1,5-lactone. The lactones were converted into methyl 3,4-O-isopropylidene-2-O-sulfonyl esters 42, 50, 62 and 68, which upon treatment with concentrated aqueous ammonia yielded the aziridino compounds. The aziridino amides 43 and 51 were reductively cleaved with hydrazine to give 3-amino-2,3-dideoxyhexonhydrazides 83 and 85, which were easily converted into the corresponding lactone 84 and acid 86. The aziridine ring of 43 and 51 was also opened with acetic acid to give the 3-amino-3-deoxyhexonic acids 79 and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97and 103 were prepared by periodate cleavage of the corresponding hexonolactones. These compounds did not react with 2-(3,4-dimethoxyphenyl)ethyl amine 105. Instead the commercially available unsubstituted 4-carboxyl tetronolactone 108 was converted into the 2-(3,4-dimethoxyphenyl)ethyl amides 110 and 111 in two steps. These amides were cyclised by the Bischler-Napieralski cyclisation to give the dihydroisoquinoline lactones 113 and 114, which were reduced to give the target tetrahydroisoquinoline lactones 115, 117 and 118.

  8. Lysophosphatidic acid synthesis and release.

    OpenAIRE

    Pagès, Céline; Simon, Marie-Françoise; Valet, Philippe; Saulnier-Blache, Jean Sébastien

    2001-01-01

    Lysophosphatidic acid (LPA) is a bioactive phospholipid controlling numerous cellular responses through the activation of specific G-protein coupled transmembrane receptors. LPA is present in several biological fluids (serum, plasma, aqueous humor) and can be secreted by several cell types (platelets, fibroblasts, adipocytes, cancer cells). Whereas, multiple pathways of synthesis and degradation of LPA have been described, their relative contribution in extracellular secretion and biodisponib...

  9. The Rate of Grafting and Some Kinetic Parameters of the Graft Copolymerization of Methacrylic Acid on Poly (Ethylene Terephthalate) Fibers with Azobisisobutyronitrile

    OpenAIRE

    ÇEL?K, Meltem; SAÇAK, Mehmet

    2000-01-01

    In this study the rate of grafting and some kinetic parameters of the graft copolymerization of methacrylic acid on poly(ethylene terephthalate) fibers with azobisisobutyronitrile was investigated. The rate of grafting was found to be proportional to the 0.94 and 1.22 powers of initiator and monomer concentrations, respectively. By carrying out the graft copolymerization reaction at four different temperatures ranging from 70 oC to 90 oC, the overall rate activation energy of the reaction was...

  10. Nanocomposites Based on Polybutylene Terephthalate Synthesized from Cyclic Oligomers of Butylene Terephthalate and Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    L.V. Bardash

    2015-03-01

    Full Text Available The paper describes structure and electric properties of nanocomposites based on polybutylene terephthalate (PBT filled by multiwalled carbon nanotubes (MWCNTs. Cyclic butylene terephthalate oligomers with low melt viscosity were used for PBT/MWCNTs nanocomposites synthesis to reach better dispersion of MWCNTs. The dependence of electric conductivity of nanocomposites on processing methods was established as well as electrical percolation threshold for PBT/MWCNTs was determined as 0.22 wt. % of MWCNTs.

  11. Fatty acid synthesis by spinach chloroplasts, 2

    International Nuclear Information System (INIS)

    By incorporation of 3H2O into the fatty acid chain in the presence of unlabelled precursor, we showed that fatty acids are synthesized from PGA, PEP and pyruvate by intact spinach chloroplasts in the light. 13C-tracer experiments confirmed that 1-C of pyruvate is decarboxylated and 2-C is incorporated into fatty acids by the chloroplasts. The patterns of fatty acids synthesized from PGA and pyruvate were the same as that from acetate. The highest rate of fatty acid synthesis was reached at the physiological concentration of PGA (3 mM) and pyruvate (1 mM). These results indicate the operation of the following path in the chloroplasts in light: PGA?PEP?pyruvate?acetylCoA?fatty acids. Since citrate and OAA were much less active and malate and glyoxylate were inert as precursors for fatty acid synthesis, PEP or pyruvate carboxylation, citrate lyase reaction and malate synthetase reaction are not involved in the formation of acetylCoA and fatty acids. Since pyruvate was much more effective as a substrate for fatty acid synthesis than lactate, acetaldehyde or acetate, direct decarboxylation path is considered to be the primary path from pyruvate to acetylCoA. The insignificant effect of chloroplast-washing on fatty acid synthesis from PGA and pyruvate indicates that the glycolytic path from PGA to pyruvate is associated with the chloroplasts. Since pyruvate was more effectively incorporated into fatty acids than acetylCoA, it is unlikely that pyruvate decarboxylation to acetylCoA is due to mitochondria contaminating the chloroplast preparation. On the basis of measurements of 3H2O incorporation in the light and dark, the activity of fatty acid synthesis in spincah leaves appears to be shared by the activities in chloroplasts (87%) and other organelles (13%). (author)

  12. Surface modification of poly(ethylene terephthalate) (PET) film by gamma-ray induced grafting of poly(acrylic acid) and its application in antibacterial hybrid film

    Science.gov (United States)

    Ping, Xiang; Wang, Mozhen; Xuewu, Ge

    2011-04-01

    Acrylic acid (AA) was facilely grafted onto poly(ethylene terephthalate) (PET) film through gamma-ray induced graft copolymerization. Silver nanoparticles produced by the chemical reduction of silver ions were then immobilized by carboxylic anions and embedded on the surface of PET-g-PAA film. It was found that the DG of PAA on PET film increases with the absorbed dose and would finally control the amount of loaded silver nanoparticles. The prepared PET-g-PAA/Ag hybrid films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The bactericidal activity of the PET-g-PAA/Ag hybrid film was evaluated by the efficiency of killing Escherichia coli. The results showed that the PET-g-PAA/Ag hybrid film has a strong and stable antibacterial activity.

  13. Modification of Poly(Ethylene Terephthalate) Fiber by Grafting of Acrylic Acid/Acrylamide for Removal of Pb+2 from Aqueous Solutions

    International Nuclear Information System (INIS)

    A new fibrous adsorbent was prepared by grafting Acrylic Acid /Acryl Amide co-monomers onto Poly(Ethylene Terephthalate) fibers. The resulting sorbent has been characterized by Fourier Transform Infrared spectroscopy, Thermo Gravimetric Analysis, Scanning Electron Microscopy and elemental analysis and studied for the preconcentration and determination of trace Pb+2 ion from water sample. The effects of reaction conditions such as monomer mixture ratio, grafting yield, polymerization. The time and temperature on grafting were investigated. Batch adsorption method was used for the pre concentration studies. Recovery of Pb+2 was 100.2% at optimum conditions. The adsorption capacity of the adsorbent was found 44.1 mg/g for Pb+2.

  14. Chemical recycling of post-consumer PET: structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature

    International Nuclear Information System (INIS)

    Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L-1 NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed. (author)

  15. Mechanical properties and morphology of biodegradable poly(lactic acid)/poly(butylene adipate-co-terephthalate) blends compatibilized by transesterification

    International Nuclear Information System (INIS)

    Highlights: ? Compatibility between PLA and PBAT is improved through transesterification. ? Elongation at break of PLA was up to almost 300%. ? Both toughness and stiffness of PLA/PBAT blends are improved significantly after the incorporation of TBT. -- Abstract: Biodegradable poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends with various tetrabutyl titanate (TBT) concentration were prepared through melt-extrusion. Mechanical properties and morphology were characterized in terms of tensile and impact testing, dynamical mechanical analysis and scanning electron micrograph (SEM). The results indicated that the overall mechanical properties (including tensile strength, elongation at break, toughness and stiffness) of PLA/PBAT blends can be improved significantly after the incorporation of TBT. The SEM micrographs demonstrated that the compatibility and strong interaction between PLA and PBAT was improved via transesterification during melt-extrusion. The interfacial debonding, pullout of PBAT, yielding deformation were the most important mechanisms to improve toughness.

  16. Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A

    International Nuclear Information System (INIS)

    When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A

  17. Synthesis of tritium labelled fluorescent eicosapolyenoic acids

    International Nuclear Information System (INIS)

    A synthesis of tritium labelled fluorescent eicosapolyenoic acids from /5, 6, 8, 9, 11, 12, 14, 15 - 3H8/ -arachidonic acid is described. The bromination-debromination steps resulted in a mixture of tritiated eicosapolyenoic acids with a system of five conjugated double bonds and ?max at 330 nm. Reaction products were separated by RP-HPLC and their fluorescent parameters were measured. Fluorescent eicosapolyenoic acids had emission max at 470 nm ( ?ex 346 nm). The molar radioactivity of acids obtained was in the range 3.3 - 5.6 TBq/mmol. (author). 3 refs

  18. Exposure to the polyester PET precursor--terephthalic acid induces and perpetuates DNA damage-harboring non-malignant human breast cells.

    Science.gov (United States)

    Luciani-Torres, Maria Gloria; Moore, Dan H; Goodson, William H; Dairkee, Shanaz H

    2015-01-01

    Identification of early perturbations induced in cells from non-cancerous breast tissue is critical for understanding possible breast cancer risk from chemical exposure. We have demonstrated previously that exposure to the ubiquitous xenoestrogens, bisphenol A (BPA) and methyl paraben, promotes the hallmarks of cancer in non-malignant human high-risk donor breast epithelial cells (HRBECs) isolated from several donors. Here we show that terephthalic acid (TPA), a major chemical precursor of polyethylene terephthalate (PET) containers used for the storage of food and beverages, increased the ER?: ER? ratio in multiple HRBEC samples, suggesting an estrogenic effect. Although, like BPA and methyl paraben, TPA also promoted resistance to tamoxifen-induced apoptosis, unlike these chemicals instead of inducing an increased S-phase fraction, TPA treatment arrested cell proliferation. DNA-PK, ATM and members of the MRN complex, known to be involved in DNA damage sensor and effector proteins, were elevated indicating induction of DNA strand breaks. Early DNA damage checkpoint response, mediated through p53/p21, led to G1 arrest in TPA-exposed cells. Removal of TPA from the growth medium resulted in the rapid induction of BCL2, increasing the ratio of anti-: pro-apoptotic proteins, together with overexpression of Cyclin A/CDK2 proteins. Consequently, despite elevated p53(pSer15) and H2AX(pSer139), indicating sustained DNA damage, TPA exposed cells resumed robust growth rates seen prior to TPA exposure. The propensity for the perpetuation of DNA aberrations that activate DNA damage pathways in non-malignant breast cells justifies careful consideration of human exposure to TPA, particularly at vulnerable life stages. PMID:25411358

  19. Synthesis of excitatory amino acid analogues

    OpenAIRE

    Goundry, WRF; Lee, V; Baldwin, JE

    2006-01-01

    A general route to excitatory amino acid analogues has been developed as exemplified by the synthesis of A-1 and A-2. The key reactions involved were a Negishi coupling of Jackson's organozinc reagent with vinyl bromide 8 and subsequent ring closure of 15 and 16 using the Mitsunobu reaction. © Georg Thieme Verlag Stuttgart.

  20. Synthesis of pyromellitic acid esters

    Science.gov (United States)

    Fedorova, V. A.; Donchak, V. A.; Martynyuk-Lototskaya, A. N.

    1985-01-01

    The ester acids necessary for studyng the thermochemical properties of pyromellitic acid (PMK)-based peroxides were investigated. Obtaining a tetramethyl ester of a PMK was described. The mechanism of an esterification reaction is discussed, as is the complete esterification of PMK with primary alcohol.

  1. Preparation of polymer blends from glycerol, fumaric acid and of poly(ethylene terephthalate) (PET) recycled; Preparacao de blendas polimericas a partir do glicerol, acido fumarico e do politereftalato de etileno (PET) pos consumo

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Marina A.O.; Guimaraes, Danilo H.; Brioude, Michel M.; Jose, Nadia M. [Instituto de Quimica, Universidade Federal da Bahia, Salvador, BA (Brazil); Prado, Luis A.S. de A. [Institut fuer Kunststoffe und Verbundwerkstoffe - Technische Universitaet Hamburg-Harburg, Hamburg (Germany)

    2011-07-01

    Polymer blends based on recycled poly(ethylene terephthalate) (PET) and poly(glycerol fumarate) polyesters were prepared in different PET concentrations. The PET powder was dispersed during the poly(glycerol fumarate) synthesis at 260 deg C. The resulting blends were characterized by X-ray diffraction. The thermal stability of the materials was evaluated by thermogravimetric analysis and differential scanning calorimetry. The morphology was studies by scanning electron microscopy. The blends were clearly immiscible. The possibility of (interfacial) compatibilization of the PET domains, caused by transesterification reactions between PET and glycerol were discussed. (author)

  2. A new approach of synthesis and morphological control of poly(ethylene terephthalate)-g-polyacrylonitrile composite film with a porous surface

    International Nuclear Information System (INIS)

    Poly(ethylene terephthalate)-g-polyacrylonitrile (PET-g-PAN) composite film with a porous surface was fabricated via gamma-ray-radiation-induced graft polymerization on PET film in an aqueous solution system. The original PET film was first irradiated by gamma ray in the aqueous solution of acrylic acid. Next, the graft polymerization of acrylonitrile (AN) was induced by gamma ray on the surface of the above modified PET film in an aqueous solution of AN. The prepared PET-g-PAN composite film has a smaller static water contact angle than the original PET film. The SEM and AFM images show that the grafted PAN layer on the surface of PET-g-PAN composite film is composed of closely-arranged spherical PAN microspheres with an average diameter of 30 nm. The gaps between the PAN microspheres form fine pores (less than 30 nm) on the surface. The gas barrier property of the PET-g-PAN composite film is much better than that of the original PET film. This work provides a facile and green method to prepare PET-g-PAN composite film with a controllable porous surface morphology by taking advantage of the radiation-induced graft polymerization technique in an aqueous solution system. - Highlights: • PET-g-PAN composite film can be prepared by radiation-induced grafting polymerization. • The PAA grafted on PET film will facilitate the following graft polymerization of AN. • The grafted PAN forms spherical microspheres with an average diameter of 30 nm. • The gaps between the PAN microspheres form a porous topology on the surface. • The gas barrier property of PET film was greatly improved by the grafting of PAN

  3. Synthesis of a conformationally constrained ?-amino acid building block.

    Science.gov (United States)

    O'Reilly, Elaine; Pes, Lara; Ortin, Yannick; Müller-Bunz, Helge; Paradisi, Francesca

    2013-02-01

    Conformationally restricted amino acids are important components in peptidomimetics and drug design. Herein, we describe the synthesis of a novel, non-proteinogenic constrained delta amino acid containing a cyclobutane ring, cis-3(aminomethyl)cyclobutane carboxylic acid (ACCA). The synthesis of the target amino acid was achieved in seven steps, with the key reaction being a base induced intramolecular nucleophilic substitution. A small library of dipeptides was prepared through the coupling of ACCA with proteinogenic amino acids. PMID:22851051

  4. New Methods towards the synthesis of beta-amino acids

    OpenAIRE

    Weiner, Barbara,

    2009-01-01

    The research presented in this thesis had the objective to use enzymes and transition metal catalysts to find new and efficient methods for the synthesis of ?-amino acids from cheap starting materials. ?-Amino acids are key structural elements of peptides, peptidomimetics and other natural products. Consequently they are essential chiral building blocks for the synthesis of pharmaceuticals. In chapter 1, recent catalytic asymmetric methods for the synthesis of ?-amino acids and derivatives ar...

  5. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations.

    Science.gov (United States)

    Karthikeyan, N; Prince, J Joseph; Ramalingam, S; Periandy, S

    2015-03-15

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The (13)C and (1)H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied. PMID:25561302

  6. NEW EFFECTIVE SYNTHESYS OF CHINCHONINIC ACIDS FROM (--?-PINENE

    Directory of Open Access Journals (Sweden)

    Oleg Radul

    2009-12-01

    Full Text Available New effective synthesis of the chiral chinchoninic acids form (--?-pinene has been elaborated. It has been shown that, the considerable increase of the yield and purity of chiral acids is achieved applying the method of under phase transfer catalysis. New effective synthesis of the chiral chinchoninic acids form (--?-pinene has been elaborated. It has been shown that, the considerable increase of the yield and purity of chiral acids is achieved applying the method of under phase transfer catalysis.

  7. Thermal modulation of fatty acid synthesis in Escherichia coli does not involve de novo enzyme synthesis.

    OpenAIRE

    Garwin, J L; Cronan, J E

    1980-01-01

    An increased ratio of unsaturated to saturated fatty acids was synthesized within 30 s after shift of Escherichia coli K-12 from 42 degrees C to 24 degrees C. This was more than 10-fold faster than the induction of beta-galactosidase. Inhibition of ribonucleic acid or protein synthesis had no effect on the response of fatty acid synthesis to temperature shift.

  8. Total synthesis of the polyenoyltetramic acid polycephalin C

    OpenAIRE

    Longbottom, DA; Morrison, AJ; Dixon, DJ; Ley, SV

    2003-01-01

    The total synthesis of the polyenoyltetramic acid polycephalin C is described. Key steps of the synthesis include a double Swern oxidation, double Takai reaction and a double Stille reaction. In addition, the absolute stereochemistry of the ring junction has been determined by synthesis of both isomers and comparison of their CD spectra with natural polycephalin C. © 2003 Elsevier Ltd. All rights reserved.

  9. Enhancement of ribosomal ribonucleic acid synthesis by deoxyribonucleic acid gyrase activity in Escherichia coli.

    Science.gov (United States)

    Oostra, B A; van Vliet, A J; Ab, G; Gruber, M

    1981-12-01

    The effect of the deoxyribonucleic acid (DNA) gyrase inhibitors coumermycin A1, novobiocin, and oxolinic acid on ribonucleic acid (RNA) synthesis in Escherichia coli was studied in vivo and in vitro. Preferential inhibition of ribosomal RNA (rRNA) synthesis was observed. No effect of oxolinic acid and coumermycin on rRNA synthesis was seen in mutants having a DNA gyrase which is resistant to these inhibitors. In a temperature-sensitive DNA gyrase mutant rRNA synthesis was decreased at nonpermissive temperatures. Thus, a functional DNA gyrase is required for rRNA synthesis. Purified DNA gyrase had no effect on rRNA synthesis in a purified system. However, DNA gyrase does show preferential stimulation of rRNA synthesis in a system supplemented with other proteins. Apparently, DNA gyrase stimulation of rRNA synthesis requires another protein. PMID:6171557

  10. Synthesis and NMR characterization of aliphatic-aromatic copolyesters by reaction of poly(ethylene terephthalate) post-consumer and poly(ethylene adipate)

    OpenAIRE

    Alessandra F. Baldissera; Carlos E. S. Valério; Nara. R. de S. Basso; Fernando Guaragna; Sandra Einloft; Martine Tessier; Alain Fradet

    2005-01-01

    An aliphatic-aromatic copolyester of poly(ethylene terephthalate), PET, and poly(ethylene adipate), PEA, PET-co-PEA, was synthesized by the high temperature melt reaction of post-consumer PET and PEA. As observed by NMR spectroscopy, the reaction yielded random copolyesters in a few minutes through ester-interchange reactions, even without added catalyst. The copolyesters obtained in the presence of a catalyst presented higher intrinsic viscosity than that obtained without the addition of cat...

  11. Synthesis of some labelled non-proteinogenic amino acids

    International Nuclear Information System (INIS)

    The literature on the synthesis of labeled non-proteinogenic amino acids contains approximately 300 papers, whereas syntheses of labeled proteinogenic amino acids are dealt with in some 800-1000 publications. However, most of the methods described in this paper for the synthesis of non-proteinogenic amino acids are also used for the preparation of the essential amino acids addition, the first category also contains ?, ?...amino acids, seleno amino acids, N-methyl and ?-methyl amino acids and sometimes have atoms or groups which are not present in the protein building blocks. Furthermore the latter group is more easily available so that methods for synthesis of non-proteinogenic amino acids are more needed

  12. Synthesis and conductivity of undecatungstozircogallic heteropoly acid

    Energy Technology Data Exchange (ETDEWEB)

    Sang Xiaoguang; Wu Qingyin; Pang Wenqin

    2003-11-15

    The undecatungstozircogallic heteropoly acid (HPA) H{sub 5}[Ga(H{sub 2}O)ZrW{sub 11}O{sub 39}].14H{sub 2}O was synthesized for the first time by the stepwise acidification and the stepwise addition of solution of the component elements. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), IR, UV, X-ray diffraction and thermal analysis. The results of AC impedance measurement show that its proton conductivity is 8.76x10{sup -4} S cm{sup -1} at room temperature (16 deg. C) and the activation energy for proton conduction is 21.20 kJ mol{sup -1}.

  13. Synthesis and conductivity of undecatungstocobaltoindic heteropoly acid

    International Nuclear Information System (INIS)

    The undecatungstocobaltoindic heteropoly acid H7[In(H2O)CoW11O39]·14H2O was synthesized for the first time by the stepwise acidification and the stepwise addition of solutions of the component elements as well as the ion exchanging-cooling method. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), IR, UV, X-ray diffraction, and thermal analysis. The IR, UV and XRD indicate that H7[In(H2O)CoW11O39]·14H2O possesses the Keggin structure. The results of AC impedance measurement show that its proton conductivity is 6.64 x 10-3 S cm-1 at room temperature (18 deg. C)

  14. Synthesis and conductivity of decatungstodivanadogermanic heteropoly acid

    International Nuclear Information System (INIS)

    The decatungstodivanadogermanic heteropoly acid H6GeW10V2O40·22H2O was synthesized for the first time by the stepwise acidification and the stepwise addition of solutions of the component elements. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), IR, UV, X-ray diffraction and thermal analysis. The IR, UV and XRD indicate that H6GeW10V2O40·22H2O possesses the Keggin structure. The results of ac impedance measurement show that its proton conductivity is 1.20 x 10-2 S cm-1 at room temperature (16 deg. C)

  15. Synthesis and conductivity of undecatungstozircogallic heteropoly acid

    International Nuclear Information System (INIS)

    The undecatungstozircogallic heteropoly acid (HPA) H5[Ga(H2O)ZrW11O39].14H2O was synthesized for the first time by the stepwise acidification and the stepwise addition of solution of the component elements. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), IR, UV, X-ray diffraction and thermal analysis. The results of AC impedance measurement show that its proton conductivity is 8.76x10-4 S cm-1 at room temperature (16 deg. C) and the activation energy for proton conduction is 21.20 kJ mol-1

  16. Fatty acid synthesis by spinach chloroplasts, 1

    International Nuclear Information System (INIS)

    Intact chloroplasts (about 70% Class I chloroplasts) isolated from spinach leaves incorporated 150 nmoles of [1-14C] acetate into fatty acids per mg chlorophyll in 1 hr at pH 8.3, 250C and 25,000 lux. On electron and phase-contrast microscopies combined with hypotonic treatment of chloroplasts, this synthetic activity was shown to be proportional to the percentage of Class I chloroplasts in the preparation. Light was necessary for the synthesis, the activity in the complete reaction mixture in the dark being only 2% of that in the light. The synthetic activity increased with increasing intensities of light to reach saturation at 6000 lux. CoA and ATP were most effective as cofactors, HCO3-, HPO42-, Mg2+ and Mn2+ were less effective. ATP could be replaced by ADP in the presence of Pi, suggesting possible supply of ATP by photophosphorylation. Omission of the NADPH-generation system and NADH did not affect the synthesis, indicating sufficient provision of endogenous NADPH and NADH in intact chloroplasts under light. Addition of DTE did not cause recovery of the synthetic activity of intact chloroplasts in the dark. (author)

  17. Synthesis of Diaminopimelic Acid, Lysine and Pipecolic Acid from Spartic Acid by Rumen Microorganisms

    Directory of Open Access Journals (Sweden)

    A.M. El-Waziry

    2012-01-01

    Full Text Available The current study was examined the formation of the three Stereoisomers (SI of 2, 6-Diaminopimelic Acid (DAP, lysine and pipecolic acid from aspartic acid by mixed rumen bacteria and protozoa. Mixed rumen bacteria and protozoa were isolated from the rumen of sheep given concentrate mixture and hay and incubated with and without aspartic acid (5 mM. The microbial suspensions were anaerobically incubated at 39°C for 12 h. The results showed that mixed rumen bacteria produced meso-DAP by 0.221 mM, LL-DAP by 0.013 mM, lysine by 0.211 mM during the 12 h incubation periods. This is the first finding to show the synthesis of DAP-SI and lysine from aspartic acid by rumen bacteria. Mixed rumen protozoa produced meso-DAP by 0.231 mM, lysine by 0.443 mM and pipecolic acid by 0.042 mM during the 12 h incubation periods. DD-DAP was not detected during the incubation periods of mixed rumen bacteria and protozoa and also LL-DAP was not detected by mixed rumen protozoa. The synthesis meso-DAP from aspartic acid by rumen protozoa was demonstrated for the first time. The results indicated that mixed rumen bacteria have the ability to synthesis meso-DAP, LL-DAP and lysine from aspartic acid meanwhile, the mixed rumen protozoa have the ability to produced meso-DAP, lysine and pipecolic acid from aspartic acid.

  18. Synthesis and NMR characterization of aliphatic-aromatic co polyesters by reaction of poly(ethylene terephthalate) post-consumer and poly(ethylene adipate)

    International Nuclear Information System (INIS)

    An aliphatic-aromatic copolyester of poly(ethylene terephthalate), PET, and poly(ethylene adipate), PEA, PET-co-PEA, was synthesized by the high temperature melt reaction of post-consumer PET and PEA. As observed by NMR spectroscopy, the reaction yielded random copolyesters in a few minutes through ester-interchange reactions, even without added catalyst. The copolyesters obtained in the presence of a catalyst presented higher intrinsic viscosity than that obtained without the addition of catalyst, due to simultaneous polycondensation and ester-interchange reactions. The structure of the aliphatic-aromatic copolyesters obtained in different PET/PEA ratio is random as observed by NMR analysis. (author)

  19. A simple synthesis of propionic-3-14C acid

    International Nuclear Information System (INIS)

    Propionic-3-14C acid was prepared by methylation of tricarbethoxymethane and subsequent hydrolysis. This method avoids the problems of malonic ester synthesis. A pure monoalkyl derivative was obtained. (author)

  20. Facile synthesis of ?-hydroxy carboxylic acids from the corresponding ?-amino acids

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh

    2014-01-01

    An effective and improved procedure is developed for the synthesis of ?-hydroxy carboxylic acids by treatment of the corresponding protonated ?-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located ? to a carboxylic acid function in order to undergo initial diazotization and successive hydroxylation, since neither ?-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved.

  1. Synthesis of 3C–SiC nanowires by reaction of poly(ethylene terephthalate) waste with SiO2 microspheres

    International Nuclear Information System (INIS)

    Highlights: •The 3C–SiC nanowires have been synthesized by reaction of poly(ethylene terephthalate) (PET) waste and SiO2 microspheres as primary reactant. •The recycling of PET wastes are fulfilled, and it is beneficial to the environment protection. •Increasing information will decrease quality if hospital costs are very different. •The prepared 3C–SiC nanowires have a good morphology. •Other polymer wastes, such as PE, PP, PVC, and PS, can also be managed with this method. -- Abstract: 3C–SiC nanowires have been synthesized by reaction of poly(ethylene terephthalate) (PET) waste with SiO2 microspheres in supercritical carbon dioxide system at 650 °C for 3 h, followed by vacuum annealing at 1500 °C for 4 h. The product was characterized by X-ray diffraction, Raman spectroscopic, Field Emission Scanning Electron Microscopy, and High-resolution Electron Microscopy. The 3C–SiC nanowires are tens of microns in length and 30–150 nm in diameter. It is found that the reaction forming 3C–SiC nanowires take place in the inner of the carbon microspheres generated from PET. The formation mechanism of the 3C–SiC nanowires was discussed

  2. Polyunsaturated fatty acids stimulate phosphatidylcholine synthesis in PC12 cells

    OpenAIRE

    Richardson, U. Ingrid; Wurtman, Richard J.

    2007-01-01

    The synthesis of phospholipids in mammalian cells is regulated by the availability of three critical precursor pools: those of choline, cytidine triphosphate and diacylglycerol. Diacylglycerols containing polyunsaturated fatty acids (PUFAs) apparently are preferentially utilized for phosphatide synthesis. PUFAs are known to play an important role in the development and function of mammalian brains. We therefore studied the effects of unsaturated, monounsaturated and polyunsaturated fatty acid...

  3. Microwave irradiated synthesis and characterization of 1, 4-phenylene bis-oxazoline form bis-(2-hydroxyethyl terephthalamide obtained by depolymerization of poly (ethylene terephthalate (PET bottle wastes

    Directory of Open Access Journals (Sweden)

    Yogesh S. Parab

    2012-04-01

    Full Text Available The aminolytic depolymerization of PET bottle waste with ethanolamine by conventional heating and microwave irradiation heating method was attempted with heterogeneous, recyclable acid catalysts such as beta zeolite (SiO2/ AlO2= 15 Na- form and montmorillonite KSF. The pure product bis-(2-hydroxyethyl terephthalamide (BHETA of aminolysis was obtained in good yield (85- 88%. The BHETA, thus obtained, was subjected to cyclization reaction by heating with polyphosphoric acid as well as by chlorination (using phosphoryl chloride, bromination (using red phosphorous and liquid bromine and nitration (conc. HNO3 + conc. H2SO4 followed by conventional and microwave irradiation heating in N,N- dimethyl formamide/ potassium carbonate solution. The product so obtained was 2, 2’-(1,4-phenylene–bis-(2-oxazoline (PBO, which has applications in polymer synthesis as a chain extender/ chain coupling agent or a cross linker. The productswere analyzed by FTIR, DSC, Mass and NMR (1H and 13C NMR.

  4. Synthesis and conductivity of undecatungstocobaltoindic heteropoly acid

    Energy Technology Data Exchange (ETDEWEB)

    Wu Qingyin [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China)]. E-mail: mqywu@sohu.com; Sang Xiaoguang [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Shao Fei [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Pang Wenqin [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130023 (China)

    2005-07-15

    The undecatungstocobaltoindic heteropoly acid H{sub 7}[In(H{sub 2}O)CoW{sub 11}O{sub 39}]{center_dot}14H{sub 2}O was synthesized for the first time by the stepwise acidification and the stepwise addition of solutions of the component elements as well as the ion exchanging-cooling method. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), IR, UV, X-ray diffraction, and thermal analysis. The IR, UV and XRD indicate that H{sub 7}[In(H{sub 2}O)CoW{sub 11}O{sub 39}]{center_dot}14H{sub 2}O possesses the Keggin structure. The results of AC impedance measurement show that its proton conductivity is 6.64 x 10{sup -3} S cm{sup -1} at room temperature (18 deg. C)

  5. Preparation and characterization of polymer blends based on recycled PET and polyester derived by terephthalic acid; Preparacao e caracterizacao de blendas polimericas a base de PET reciclado e poliester derivado do acido tereftalico

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, L.; Miranda, C.S.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M., E-mail: leandro.ohara@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais

    2010-07-01

    Environmentally friendly materials, made from industrial waste, are being increasingly used as a solution to the growing amount of waste generated by society, but also as a cheaper alternative to replace conventional materials for use in construction. In this work were investigated the properties of polymer blends based on recycled PET and a polyester derived from terephthalic acid and glycerin, a co-product of biodiesel. The samples were characterized by XRD, TGA, DSC, FTIR and SEM. The polyester synthesized showed a degradation event near 300 deg C. The blends with higher ratio of PET showed thermal behavior similar to pure PET. The X-ray diffraction showed that the polymer blends are semicrystalline materials. The micrographs presents the presence of a smooth surface, indicating the possibility of miscibility between the arrays. Therefore, the blending makes possible the fabrication of low-cost materials with applications in several areas. (author)

  6. Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia

    Science.gov (United States)

    Weber, Arthur L.

    1998-01-01

    Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.

  7. Synthesis and NMR characterization of aliphatic-aromatic copolyesters by reaction of poly(ethylene terephthalate post-consumer and poly(ethylene adipate

    Directory of Open Access Journals (Sweden)

    Alessandra F. Baldissera

    2005-03-01

    Full Text Available An aliphatic-aromatic copolyester of poly(ethylene terephthalate, PET, and poly(ethylene adipate, PEA, PET-co-PEA, was synthesized by the high temperature melt reaction of post-consumer PET and PEA. As observed by NMR spectroscopy, the reaction yielded random copolyesters in a few minutes through ester-interchange reactions, even without added catalyst. The copolyesters obtained in the presence of a catalyst presented higher intrinsic viscosity than that obtained without the addition of catalyst, due to simultaneous polycondensation and ester-interchange reactions. The structure of the aliphatic-aromatic copolyesters obtained in different PET/PEA ratio is random as observed by NMR analysis.

  8. Synthesis and NMR characterization of aliphatic-aromatic copolyesters by reaction of poly(ethylene terephthalate) post-consumer and poly(ethylene adipate)

    Scientific Electronic Library Online (English)

    Alessandra F., Baldissera; Carlos E. S., Valério; Nara. R. de S., Basso; Fernando, Guaragna; Sandra, Einloft; Martine, Tessier; Alain, Fradet.

    2005-03-01

    Full Text Available An aliphatic-aromatic copolyester of poly(ethylene terephthalate), PET, and poly(ethylene adipate), PEA, PET-co-PEA, was synthesized by the high temperature melt reaction of post-consumer PET and PEA. As observed by NMR spectroscopy, the reaction yielded random copolyesters in a few minutes through [...] ester-interchange reactions, even without added catalyst. The copolyesters obtained in the presence of a catalyst presented higher intrinsic viscosity than that obtained without the addition of catalyst, due to simultaneous polycondensation and ester-interchange reactions. The structure of the aliphatic-aromatic copolyesters obtained in different PET/PEA ratio is random as observed by NMR analysis.

  9. Possibilities of enzyme synthesis of radioactive nuclei acid components

    International Nuclear Information System (INIS)

    The possibilities of enzyme synthesis of nucleic acid metabolites labelled with 14C or 3H are reviewed. Attention is paid namely to the enzyme synthesis methods of radioactive nucleotides of ribonucleic and deoxyribonucleic acids, especially of the nucleoside-5'-triphosphates of adenine, guanine, uracil, cytosine and thymine which are the direct precursors of nucleic acid biosynthesis. Experimental results obtained in the phosphorylation of radioactive nucleoside-5'-monophosphates catalyzed by purified enzyme preparations from Escherichia coli B are summarized. The possibility of the enzyme preparation of radioactive orotidine-5'-monophosphate and uridine-5'-monophosphate is shown on phosphoribosylation of uracil or orotic acid by the catalytic effect of enzymes present in the cell-free extracts of Brevibacterium ammoniagenes. The methods of the enzyme synthesis of radioactive nucleotides of thymine utilizing the properties of thymine-dependent mutants of Escherichia coli are indicated. (author)

  10. Asymmetric synthesis of carbon-14 labeled alpha amino acids

    International Nuclear Information System (INIS)

    Adaptation of existing methodology for the asymmetric synthesis of unlabeled amino acids led to preparations of L-phenylalanine-2-14C and L-tyrosine-(ring-3,4-14C2), each having high radiochemical and enantiomeric purity. Reaction of the diketopiperazine derived from L-valine and glycine with an appropriate aldehyde provides a 2,3-dehydroamino acid precursor which undergoes asymmetric hydrogenation. Acid hydrolysis provides the new L-amino acid and L-valine (or whichever chiral amino acid was used to prepare the diketopiperazine and to induce asymmetric reduction) and these are readily separated. This approach can be applied to the synthesis of any carbon-labeled chiral alpha amino acid using labeled achiral starting materials. (author). 4 refs

  11. Synthesis of heterocycles from anthranilic acid and its derivatives

    OpenAIRE

    Wiklund, Per

    2004-01-01

    Anthranilic acid (2-aminobenzoic acid, Aa) is the biochemical precursor to the amino acid tryptophan, as well as a catabolic product of tryptophan in animals. It is also integrated into many alkaloids isolated from plants. Aa is produced industrially for production of dyestuffs and pharmaceuticals. The dissertation gives a historical background and a short review on the reactivity of Aa. The synthesis of several types of nitrogen heterocycles from Aa is discussed. Treatme...

  12. Acetylsalicylic acid: Incoming 150 years of the first synthesis

    OpenAIRE

    Mijin Dušan Ž.; Stankovi? Milena; Petrovi? Slobodan D.; Blagojevi? Milorad

    2002-01-01

    Acetylsalicylic acid is one of the most fascinating and versatile drugs known to medicine, as well as one of the oldest. Acetylsalicylic acid is a drug which is safe, with analgetic, antirheumatic, anti-inflammatory antiplatelet and antithrombotic action. It may be applied not only in clinical practice, but also as prevention. The first known use of an acetylsalicylic acid-like preparation can be traced to ancient Greece. In 1853 Charles Gerhardt published the first synthesis of acetylsalicyl...

  13. Synthesis of ?-(S-methyl)thioaspartic acid and derivatives

    OpenAIRE

    Heredia-Moya, Jorge; KIRK, KENNETH L.

    2008-01-01

    ?-(S-Methyl)thioaspartic acid occurs as a posttranslational modification at position 88 in E. coli ribosomal protein S12, a position that is a mutational hotspot resulting in both antibiotic-resistant and antibiotic-sensitive phenotypes. Critical to research designed to determine the biological function of ?-(S-methyl)thioaspartic acid will be the availability of synthetic ?-(S-methyl)thioaspartic acid as well as derivatives designed for peptide incorporation. We report here the synthesis of ...

  14. Fatty Acid Synthesis by Indonesian Marine Diatom, Chaetoceros gracilis

    Directory of Open Access Journals (Sweden)

    ALBERTA RIKA PRATIWI

    2009-12-01

    Full Text Available Since the primary storage nutrients in diatoms consist of lipid, they are potential for the industrial fatty acid production. High value fatty acids include arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. This study aimed to analyze fatty acid synthesis by Chaetoceros gracilis diatom during growth. There was a large increase in lipid yield from 4pg cell-1 mass of lipid per cell at the exponential phase to 283pg cell-1 at stationary phase. The lipid concentrations also increased significantly from the stationary phase to the death phase, but not significantly from the end exponential phase to the stationary phase. The relative percentage of saturated fatty acid (SAFA of the total fatty acid was higher than that of monounsaturated fatty acid (MUFA and polyunsaturated fatty acid (PUFA at all of growth phase. The highest PUFA was found at stationary phase at the same time when SAFA was being the lowest. The majority of SAFA was palmitic acid (24.03-40.35%. MUFA contained significant proportion of oleic acid (19.6-20.9%. Oleic acid, linoleic acid and ?-linolenic acid were found at every stage growth. These fatty acids are considered as precursor for production of long chain PUFA-Docosahexaenoic acid (DHA/22:6?3 through series of desaturation and elongation step with all of desaturase enzyme (?8-D, ?9-D, ?12-D, ?15-D, ?17-D, ?6-D, ?5-D, and ?4-D and elongase enzyme (E.

  15. The synthesis of glutamic acid in the absence of enzymes: Implications for biogenesis

    Science.gov (United States)

    Morowitz, Harold; Peterson, Eta; Chang, Sherwood

    1995-01-01

    This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis.

  16. Synthesis of new fatty acids amides from aminolysis of fatty acid methyl esters (FAMEs)

    International Nuclear Information System (INIS)

    Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce cytotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs). (author)

  17. Synthesis of imidazol-1-yl-acetic acid hydrochloride: A key intermediate for zoledronic acid

    OpenAIRE

    Singh, Santosh Kumar; Manne, Narendra; Ray, Purna Chandra; Pal, Manojit

    2008-01-01

    A convenient and practical synthesis of imidazol-1-yl-acetic acid hydrochloride was achieved via N-alkylation of imidazole using tert-butyl chloroacetate followed by a non-aqueous ester cleavage of the resulting imidazol-1-yl-acetic acid tert-butyl ester in the presence of titanium tetrachloride. The synthesized imidazol-1-yl-acetic acid hydrochloride was then utilized to prepare zoledronic acid.

  18. Differential diagnosis in patients with suspected bile acid synthesis defects

    Directory of Open Access Journals (Sweden)

    Dorothea Haas

    2012-01-01

    Full Text Available AIM: To investigate the clinical presentations associated with bile acid synthesis defects and to describe identification of individual disorders and diagnostic pitfalls. METHODS: Authors describe semiquantitative determination of 16 urinary bile acid metabolites by electrospray ionization-tandem mass spectrometry. Sample preparation was performed by solid-phase extraction. The total analysis time was 2 min per sample. Authors determined bile acid metabolites in 363 patients with suspected defects in bile acid metabolism. RESULTS: Abnormal bile acid metabolites were found in 36 patients. Two patients had bile acid synthesis defects but presented with atypical presentations. In 2 other patients who were later shown to be affected by biliary atresia and cystic fibrosis the profile of bile acid metabolites was initially suggestive of a bile acid synthesis defect. Three adult patients suffered from cerebrotendinous xanthomatosis. Nineteen patients had peroxisomal disorders, and 10 patients had cholestatic hepatopathy of other cause. CONCLUSION: Screening for urinary cholanoids should be done in every infant with cholestatic hepatopathy as well as in children with progressive neurological disease to provide specific therapy.

  19. Regulation of collagen synthesis by ascorbic acid.

    OpenAIRE

    Murad, S; Grove, D.; Lindberg, K A; Reynolds, G.; Sivarajah, A; Pinnell, S R

    1981-01-01

    After prolonged exposure to ascorbate, collagen synthesis in cultured human skin fibroblasts increased approximately 8-fold with no significant change in synthesis of noncollagen protein. This effect of ascorbate appears to be unrelated to its cofactor function in collagen hydroxylation. The collagenous protein secreted in the absence of added ascorbate was normal in hydroxylysine but was mildly deficient in hydroxyproline. In parallel experiments, lysine hydroxylase (peptidyllysine, 2-oxoglu...

  20. Biobased synthesis of acrylonitrile from glutamic acid

    OpenAIRE

    Le Notre, J.E.L.; Scott, E. L.; Franssen, M.C.R.; Sanders, J.P.M.

    2011-01-01

    Glutamic acid was transformed into acrylonitrile in a two step procedure involving an oxidative decarboxylation in water to 3-cyanopropanoic acid followed by a decarbonylation-elimination reaction using a palladium catalyst

  1. Catalytic methylenedianiline synthesis on porous solid acids

    OpenAIRE

    Salzinger, Michael

    2010-01-01

    Methylenedianiline (MDA) is an important raw material for the production of polyurethanes, synthesized from aniline and formaldehyde by an acid catalyzed reaction. Currently HCl is applied as catalyst. Replacing mineral acids by solid acids is of considerable interest for transforming processes towards green chemistry. In this work the SN2-type reaction mechanism and the reaction network of the formation of MDA over solid acid catalysts has been elucidated. The influence of pore size and geom...

  2. Proton and deuterium NMR experiments in zero field. [Perdeuterated p-demethoxybenzene, perdeuterated malonic acid, diethyl terephthalate-d4, nonadecane-2,2'-D2, sodium propionate-D2

    Energy Technology Data Exchange (ETDEWEB)

    Millar, J.M.

    1986-02-01

    High field solid-state NMR lineshapes suffer from inhomogeneous broadening since resonance frequencies are a function of molecular orientation. Time domain zero field NMR is a two-dimensional field-cycling technique which removes this broadening by probing the evolution of the spin system under zero applied field. The simplest version, the sudden transition experiment, induces zero field evolution by the sudden removal of the applied magnetic field. Theory and experimental results of this experiment and several variations using pulsed dc magnetic fuelds to initiate zero field evolution are presented. In particular, the pulsed indirect detection method allows detection of the zero field spectrum of one nuclear spin species via another (usually protons) by utilizing the level crossings which occur upon adiabatic demagnetization to zero field. Experimental examples of proton/deuteron systems are presented which demonstrate the method results in enhanced sensitivity relative to that obtained in sudden transition experiments performed directly on deuterium. High resolution /sup 2/H NQR spectra of a series of benzoic acid derivatives are obtained using the sudden transition and indirect detection methods. Librational oscillations in the water molecules of barium chlorate monohydrate are studied using proton and deuterium ZF experiments. 177 refs., 88 figs., 2 tabs.

  3. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    OpenAIRE

    Akiyoshi Hoshino; Fumihide Kanaya; Kenji Yamamoto; Yoshinobu Manome; Kouki Fujioka; Tomoo Shiohara; Yasuhiro Futamura

    2009-01-01

    Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research...

  4. Synthesis of glycosyl-amino acids of biological interest

    International Nuclear Information System (INIS)

    This work describes the synthesis of the glycosylated amino acids ?GlcNAc-Thr, ?GlcNAc-Thr and ?LacNAc-Thr by the glycosylation reaction of the amino acid threonine with the corresponding glycosyl donors ?GlcNAcCl and ?LacN3Cl. The glycosylated amino acids containing the sugar units ?-D-GlcNAc and ?-D-LacNAc O-linked to threonine amino acids are related to O-glycans found in mucins of the parasite Trypanosoma cruzi, while the corresponding ?-D-GlcNAc isomer is involved in cellular signaling events. (author)

  5. Enzymatic synthesis of [3-14C] cinnamic acid

    International Nuclear Information System (INIS)

    Convenient and efficient route of the synthesis of [3-14C] cinnamic acid is reported. [1-14C] Benzoic acid, prepared by carbonation of Grignard reagent with [14C] carbon dioxide, was reduced to [1-14C] benzyl alcohol. In the enzymatic step this alcohol was selectively oxidised to [1-14C] benzaldehyde using enzyme YADH (Ec. 1.1.1.1) and immediately condensed with malonic acid. This combined chemical and enzymatic approach allows to obtain [3-14C] cinnamic acid with radiochemical yield higher than 50% in respect to the starting alcohol. (author)

  6. Acetylsalicylic acid: Incoming 150 years of the first synthesis

    Directory of Open Access Journals (Sweden)

    Mijin Dušan Ž.

    2002-01-01

    Full Text Available Acetylsalicylic acid is one of the most fascinating and versatile drugs known to medicine, as well as one of the oldest. Acetylsalicylic acid is a drug which is safe, with analgetic, antirheumatic, anti-inflammatory antiplatelet and antithrombotic action. It may be applied not only in clinical practice, but also as prevention. The first known use of an acetylsalicylic acid-like preparation can be traced to ancient Greece. In 1853 Charles Gerhardt published the first synthesis of acetylsalicylic acid. Felix Hoffmann, a chemist for Friedrich Bayer, a German dye company obtained a patent on acetylsalicylic acid some 40 years later. Bayer coined the name Aspirin for the new product. The 20 in century was the century in which many researchers in many companies tried to improve the synthesis of acetylsalicylic acid not only in terms of yield but also purity. This paper describes the history, use, mechanism of action, synthesis and production as well as the purification and stability of acetylsalicylic acid.

  7. Scientific Opinion on the safety evaluation of the active substances, terephthalic acid, dimethyl ester , polymer with 1,4-butanediol, cyclized, polymers with glycidyl methacrylate, hydroxyl-terminated polybutadiene, methyl methacrylate and styrene, and cobalt stearate for use in food contact materials

    OpenAIRE

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2012-01-01

    This scientific opinion of EFSA deals with the safety evaluation of the oxygen absorber (terephthalic acid, dimethyl ester, polymer with 1,4-butanediol, cyclized, polymers with glycidyl methacrylate, hydroxyl-terminated polybutadiene, methyl methacrylate and styrene) copolymer (CAS No 1223402-34-3, FCM substance No 1005) and the oxidation catalyst cobalt stearate (CAS No 1002-88-6 and FCM Substance No 1004), intended to be used up to a maximum percentage of 1% in polyethylene terepht...

  8. Photo destruction of mechanically stressed polyethylene terephthalate

    International Nuclear Information System (INIS)

    Present article is devoted to photo destruction of mechanically stressed polyethylene terephthalate. The influence of tensile load on photo processes which pass in polyethylene terephthalate was studied by means of spectroscopy method.

  9. ASYMMETRIC AMINO-ACID SYNTHESIS - PREPARATION OF THE BETA-ANION DERIVED FROM ASPARTIC-ACID

    OpenAIRE

    Baldwin, J; Moloney, M; North, M

    1989-01-01

    (S)-1-t-Butyl 4-methyl N-benzyloxycarbonylaspartate (5a), and (S)-1-t-butyl 4-allyl N-benzyloxycarbonylaspartate (5b) have been synthesized from (S)-aspartic acid (2), and can be readily alkylated and hydroxyalkylated at the ?-carbon for asymmetric amino acid synthesis.

  10. Alternative kynurenic acid synthesis routes studied in the rat cerebellum

    OpenAIRE

    Blanco Ayala, Tonali; Lugo Huitrón, Rafael; Carmona Aparicio, Liliana; Ramírez Ortega, Daniela; González Esquivel, Dinora; Pedraza Chaverrí, José; Pérez de la Cruz, Gonzalo; Ríos, Camilo; Schwarcz, Robert; Pérez de la Cruz, Verónica

    2015-01-01

    Kynurenic acid (KYNA), an astrocyte-derived, endogenous antagonist of ?7 nicotinic acetylcholine and excitatory amino acid receptors, regulates glutamatergic, GABAergic, cholinergic and dopaminergic neurotransmission in several regions of the rodent brain. Synthesis of KYNA in the brain and elsewhere is generally attributed to the enzymatic conversion of L-kynurenine (L-KYN) by kynurenine aminotransferases (KATs). However, alternative routes, including KYNA formation from D-kynurenine (D-KYN)...

  11. Synthesis of conformationally restricted amino acids - Highly versatile scaffolds

    OpenAIRE

    Sahr, Florian A.

    2010-01-01

    The synthesis of different cispentacin derivatives as well as of a conformational restricted gamma-amino acid was accomplished starting from furan methyl ester and the thereof derived trans-substituted gamma-butyrolactone respectively. The keystep in this synthetic approach is a [3+2]-nitrone-cycloaddition reaction affording two diastereomeric products which were subsequently transformed in a straightforward manner. These amino acids have a broad range of potential applications like in the fi...

  12. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele; Stensbøl, Tine B; Madsen, Ulf; Bräuner-Osborne, Hans; Russo, Emilio; De Sarro, Giovambattista; Bruno, Giuseppe; De Micheli, Carlo

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them behaved as antagonists at mGluR1,5 and as agonists at mGluR2. Furthermore, whereas (+/-)-6 was inactive at all ionotropic glutamate receptors, (+/-)-7 displayed a quite potent antagonism at the NMDA receptor...

  13. Synthesis and Chemistry of Tetronic Acids

    OpenAIRE

    Tejedor, David; García-Tellado, Fernando

    2004-01-01

    Tetronic acids (4-hydroxy-2(5H)-furanones) form a subclass of ?-hydroxybutenolides with the generic structure 1. The best known members of this family are vitamin C (ascorbic acid) 2 and pennicillic acid 3. A great number of these compounds and their metabolites are found in many natural products, which exhibit a wide array of biological properties. The aim of this review is to cover the current synthetic methodologies developed to build these molecules and their specific chemistry more th...

  14. Synthesis of (purin-6-yl) amino acids.

    Czech Academy of Sciences Publication Activity Database

    ?apek, Petr; Hocek, Michal

    Odense : University of Southern Denmark, 2005. P14. [Nucleic Acid Chemical Biology (NACB) PhD Summer School. Novel Synthetic Nucleic Acids and the Targeting of Biologically Important RNAs. 19.06.2005-23.06.2005, Odense] R&D Projects: GA ?R(CZ) GA203/03/0035; GA MŠk(CZ) 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : purines * nucleosides * amino acids Subject RIV: CC - Organic Chemistry

  15. Enzymatic routes for the synthesis of ursodeoxycholic acid.

    Science.gov (United States)

    Eggert, Thorsten; Bakonyi, Daniel; Hummel, Werner

    2014-12-10

    Ursodeoxycholic acid, a secondary bile acid, is used as a drug for the treatment of various liver diseases, the optimal dose comprises the range of 8-10mg/kg/day. For industrial syntheses, the structural complexity of this bile acid requires the use of an appropriate starting material as well as the application of regio- and enantio-selective enzymes for its derivatization. Most strategies for the synthesis start from cholic acid or chenodeoxycholic acid. The latter requires the conversion of the hydroxyl group at C-7 from ?- into ?-position in order to obtain ursodeoxycholic acid. Cholic acid on the other hand does not only require the same epimerization reaction at C-7 but the removal of the hydroxyl group at C-12 as well. There are several bacterial regio- and enantio-selective hydroxysteroid dehydrogenases (HSDHs) to carry out the desired reactions, for example 7?-HSDHs from strains of Clostridium, Bacteroides or Xanthomonas, 7?-HSDHs from Clostridium, Collinsella, or Ruminococcus, or 12?-HSDH from Clostridium or from Eggerthella. However, all these bioconversion reactions need additional steps for the regeneration of the coenzymes. Selected multi-step reaction systems for the synthesis of ursodeoxycholic acid are presented in this review. PMID:25131646

  16. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    Directory of Open Access Journals (Sweden)

    Akiyoshi Hoshino

    2009-06-01

    Full Text Available Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1 system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source and keto acids (oxylic acid sources. In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.

  17. Stereoselective synthesis of stable-isotope-labeled amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

    1994-12-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

  18. Synthesis and characterization of polyamide and polyester, from glycerol and dicarboxylic acids, polymeric blends

    International Nuclear Information System (INIS)

    In this work were prepared and characterized polyamide and polyester blends. The polyester, called PAT, was produced in a becker equipped with high-torque mechanical stirrer, thermometer and condenser Claisen, by adding of glycerol, adipic acid, terephthalic acid and catalyst. The blends films were prepared by physical mixture followed by thermal compression. The polymeric blends and the pure materials were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the blends are semi-crystalline and have good thermal behavior, besides, it evidences that the PAT and polyamide phases are immiscible. (author)

  19. On synthesis of silicoaluminotungstic heteropoly acid

    International Nuclear Information System (INIS)

    A possibility to preparation of silicoaluminotungstic heteropoly acid using 183W and 27Al NMR method was investigated. Heteropoly acid H5SiW11Al(H2O)O39 is made by two methods: ether extraction and by means of electrodialysis in double-chamber apparatus with semipermeable membrane from cation-exchange resin. Concentrated aqueous solution containing heteropoly acid based on SiW11Al(H2O)O395- anion with impurity of 15 % H4SiW12O40 was obtained by electrodialysis. Conducted study revealed that heteropoly acid H5SiW11Al(H2O)O39 (or its based oligomer) may be prepared as not stable (to heating and prolonged endurance) aqueous solution, other than solid form

  20. Investigation of Raman spectra of polyethylene terephthalate

    Science.gov (United States)

    Zhu, Changjun; Tong, Na; Song, Lixin; Zhang, Guoqing

    2015-08-01

    Raman spectrometry was employed to study the characteristics of Raman spectra of polyethylene terephthalate (PET), which were treated with sodium hydroxide, sulfuric acid and copper sulfate, respectively. Raman spectra under different conditions were obtained and the characteristics of the Raman spectra were analyzed. The morphology structures were observed under different conditions using Atomic Force Microscope. The results show that the spectral intensity of PET treated with sodium hydroxide is higher than that untreated between 200-1750 cm-1, while the intensity of PET treated with sodium hydroxide is lower than that untreated beyond 1750 cm-1 and the fluorescence background of Raman spectra is decreased. The spectral intensity of PET treated with sulfuric acid is remarkably reduced than that untreated, and the intensity of PET treated with copper sulphate is much higher than that untreated.

  1. Poli(tereftalato de etileno), PET: uma revisão sobre os processos de síntese, mecanismos de degradação e sua reciclagem / Poly(ethylene terephthalate), PET: a review on the synthesis processes, degradation mechanisms and its recycling

    Scientific Electronic Library Online (English)

    Wanderson, Romão; Márcia A. S., Spinacé; Marco-A. De, Paoli.

    2009-06-01

    Full Text Available Apresentamos uma revisão sobre o poli(tereftalato de etileno) enfatizando os processos de síntese e os mecanismos de degradação. Atualmente o Brasil apresenta um dos maiores índices mundiais de reciclagem mecânica deste polímero, correspondendo a um percentual de 53%. O sucesso desse termoplástico n [...] a indústria de reciclagem deve-se à sua ampla diversidade de aplicações, desde a indústria têxtil (multifilamento) até as indústrias de alimentos, onde as embalagens recicladas grau alimentício poderão ser misturadas com a resina virgem em diversas proporções e reprocessadas para o uso. Uma abordagem sobre a atual legislação do uso de PET reciclado em contato com alimentos também é mostrada neste trabalho. No processo de síntese do PET realizado em duas ou três etapas, são usados comonômeros e aditivos para otimizar as condições de processamento do material. Entretanto, tanto durante a síntese como no processo de reciclagem, ocorrem reações de degradação (termomecânica e termo-oxidativa) e reações secundárias, formando acetaldeído, oligômeros, e o dietileno glicol. A presença desses "contaminantes" acelera o processo de degradação do polímero, afetando a qualidade do produto final. Abstract in english We present a review on poly(ethylene terephthalate), emphasizing the synthesis processes and the degradation mechanisms. Brazil is currently among the countries that most recycle PET, with 53% of this polymer being mechanically recycled. The success of this thermoplastic in the recycling industry is [...] due to its large diversity of applications, from the textile industry to food packaging, where the food grade recycled packages will be mixed with the pristine resin for reprocessing and use. We also discuss the present legal aspects concerning PET recycling and its use in contact with food. In the synthesis of PET, usually done in two or three steps, several co-monomers and additives are used to optimize the final properties and processing conditions. Additionally, during the synthesis, processing and recycling, several degradation (thermomechanical and thermo-oxidation) and secondary reactions occur, producing acetaldehydes, oligomers and diethyleneglicol. The presence of these "contaminants" accelerates the degradation process of the polymer affecting the final product characteristics.

  2. Poli(tereftalato de etileno, PET: uma revisão sobre os processos de síntese, mecanismos de degradação e sua reciclagem Poly(ethylene terephthalate, PET: a review on the synthesis processes, degradation mechanisms and its recycling

    Directory of Open Access Journals (Sweden)

    Wanderson Romão

    2009-06-01

    Full Text Available Apresentamos uma revisão sobre o poli(tereftalato de etileno enfatizando os processos de síntese e os mecanismos de degradação. Atualmente o Brasil apresenta um dos maiores índices mundiais de reciclagem mecânica deste polímero, correspondendo a um percentual de 53%. O sucesso desse termoplástico na indústria de reciclagem deve-se à sua ampla diversidade de aplicações, desde a indústria têxtil (multifilamento até as indústrias de alimentos, onde as embalagens recicladas grau alimentício poderão ser misturadas com a resina virgem em diversas proporções e reprocessadas para o uso. Uma abordagem sobre a atual legislação do uso de PET reciclado em contato com alimentos também é mostrada neste trabalho. No processo de síntese do PET realizado em duas ou três etapas, são usados comonômeros e aditivos para otimizar as condições de processamento do material. Entretanto, tanto durante a síntese como no processo de reciclagem, ocorrem reações de degradação (termomecânica e termo-oxidativa e reações secundárias, formando acetaldeído, oligômeros, e o dietileno glicol. A presença desses "contaminantes" acelera o processo de degradação do polímero, afetando a qualidade do produto final.We present a review on poly(ethylene terephthalate, emphasizing the synthesis processes and the degradation mechanisms. Brazil is currently among the countries that most recycle PET, with 53% of this polymer being mechanically recycled. The success of this thermoplastic in the recycling industry is due to its large diversity of applications, from the textile industry to food packaging, where the food grade recycled packages will be mixed with the pristine resin for reprocessing and use. We also discuss the present legal aspects concerning PET recycling and its use in contact with food. In the synthesis of PET, usually done in two or three steps, several co-monomers and additives are used to optimize the final properties and processing conditions. Additionally, during the synthesis, processing and recycling, several degradation (thermomechanical and thermo-oxidation and secondary reactions occur, producing acetaldehydes, oligomers and diethyleneglicol. The presence of these "contaminants" accelerates the degradation process of the polymer affecting the final product characteristics.

  3. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    OpenAIRE

    Onciu, M.; F. Tanasa; C. Chiriac

    2005-01-01

    Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP) and pyridine (Py) as bases and N-methyl-2-pyrolidinone (NMP) as solvent, at reflux (180-190°C) for 8-12 hours.

  4. The optimisation study of tbp synthesis process by phosphoric acid

    International Nuclear Information System (INIS)

    The present work deals with the optimisation study of TBP synthesis process by phosphoric acid. This way of synthesis is more advantageous than POCL3 or P2O5 as phosphatant agents. these latters are toxic and dangerous for the environnement. The optimisation study is based on a series of 16 experiences taking into account the range of variation of the following parameters : temperature, pressure, reagents mole ratio, promoter content. the yield calculation is based on the randomisation of an equation including all parameters. the resolution of this equation gave a 30% TBP molar ratio. this value is in agreement with that of experimental data

  5. Preferential inhibition of ribonucleic acid synthesis by a new thiosemicarbazone possessing antibacterial and antiparasitic properties.

    OpenAIRE

    Brown, R.E.; Stancato, F A; Wolfe, A D

    1981-01-01

    We determined the influence of the azacycloheptane derivative (H) of a 2-acetylpyridine thiosemicarbazone on growth and macromolecular synthesis in Escherichia coli AT-9. Thiosemicarbazone H caused bacteriostasis and a primary inhibition of ribonucleic acid synthesis; secondary effects included inhibition of deoxyribonucleic acid and protein synthesis. Addition of cooper or other transition elements was not necessary for these inhibitions.

  6. Fatty acid effects on fibroblast cholesterol synthesis

    International Nuclear Information System (INIS)

    Two cell lines of normal (CRL 1475, GM5565) and of familial hypercholesterolemia (FH) (CM 486,488) fibroblasts were preincubated with medium containing the growth factor ITS, 2.5 mg/ml fatty acid-free BSA, or 35.2 ?mol/ml of these fatty acids complexed with 2.5 mg BSA/ml: stearic (18:0), caprylic (8:0), oleic (18:1;9), linoleic (18:2;9,12), linolenic (18:3;9,12,15), docosahexaenoic (22:6;4,7,10,13,16,19)(DHA) or eicosapentaenoic (20:5;5,8,11,14,17)(EPA). After 20 h, cells were incubated for 2 h with 0.2 ?Ci [14C]acetate/ml. Cells were hydrolyzed; an aliquot was quantitated for radioactivity and protein. After saponification and extraction with hexane, radioactivity in the aqueous and organic phases was determined. The FH cells always incorporated 30-90% more acetate/mg protein than normal cells but the pattern of the fatty acid effects was similar in both types. When the values were normalized to 1 for the BSA-only group, cells with ITS had the greatest [14C]acetate incorporation (1.45) followed by the caprylic group (1.14). Cells incubated with 18:3, 20:6 or 22:6 incorporated about the same amount as BSA-only. Those preincubated with 18:2, 18:1, 18:0 showed the least acetate incorporation (0.87, 0.59 and 0.52, respectively). The percentage of total 14C counts which extracted into hexane was much greater in FH cells; however, these values varied with the fatty acid, e.g., 1.31(18:0) and 0.84(8:0) relative to 1

  7. Inhibition of fatty acid synthesis in rat hepatocytes by exogenous polyunsaturated fatty acids is caused by lipid peroxidation

    DEFF Research Database (Denmark)

    Mikkelsen, L.; Hansen, Harald S.; Grunnet, N.; Dich, J.

    1993-01-01

    Rat hepatocyte long-term cultures were utilized to investigate the impact of different polyunsaturated fatty acids (PUFA) on the insulin-induced de novo fatty acid synthesis in vitro. The addition of 0.5 mM albumin-complexed oleic, linoleic, columbinic, arachidonic, eicosapentaenoic or docosahexaenoic acid resulted in a marked suppression of fatty acid synthesis. By evaluation of cell viability (determined as the leakage of lactate dehydrogenase (LDH)) it turned our, that the antioxidant used (5...

  8. Microwave-Promoted synthesis of novel N-Arylanthranilic acids

    Scientific Electronic Library Online (English)

    Mauro A., Bueno; Larissa R. S. P., Silva; Arlene G., Corrêa.

    Full Text Available Nesse trabalho é relatada a síntese de uma série de ácidos N-aril antranílicos inéditos, com bons a excelentes rendimentos, empregando irradiação de microondas como fonte de aquecimento para promover a reação de acoplamento de Ullmann entre ácidos antranílicos e brometos de arila contendo grupos sub [...] stituintes doadores ou aceptores de elétrons. Abstract in english In this paper we report the synthesis of a series of novel N-aryl anthranilic acids, with good to excellent yields, employing microwaves as heat source to promote the Ullmann coupling between anthranilic acids and aryl bromides possessing electron donating or withdrawing groups. [...

  9. Cyclic diguanylic acid and cellulose synthesis in Agrobacterium tumefaciens.

    OpenAIRE

    Amikam, D; Benziman, M.

    1989-01-01

    The occurrence of the novel regulatory nucleotide bis(3',5')-cyclic diguanylic acid (c-di-GMP) and its relation to cellulose biogenesis in the plant pathogen Agrobacterium tumefaciens was studied. c-di-GMP was detected in acid extracts of 32P-labeled cells grown in various media, and an enzyme responsible for its formation from GTP was found to be present in cell-free preparations. Cellulose synthesis in vivo was quantitatively assessed with [14C]glucose as a tracer. The organism produced cel...

  10. Inhibition of fatty acid synthesis in rat hepatocytes by exogenous polyunsaturated fatty acids is caused by lipid peroxidation

    DEFF Research Database (Denmark)

    Mikkelsen, L.; Hansen, Harald S.

    1993-01-01

    Rat hepatocyte long-term cultures were utilized to investigate the impact of different polyunsaturated fatty acids (PUFA) on the insulin-induced de novo fatty acid synthesis in vitro. The addition of 0.5 mM albumin-complexed oleic, linoleic, columbinic, arachidonic, eicosapentaenoic or docosahexaenoic acid resulted in a marked suppression of fatty acid synthesis. By evaluation of cell viability (determined as the leakage of lactate dehydrogenase (LDH)) it turned our, that the antioxidant used (50 µM a-tocopherol phosphate) had a low antioxidant activity, resulting in cytotoxic effects by the peroxidized PUFA. Arachidonic acid and eicosapentaenoic acid showed a dose- and time-dependent cytotoxicity. Two other antioxidants: 50 µM a-tocopherol acid succinate and 1 µM N,N'-diphenyl-1,4-phenylenediamine, both proved more efficient than a-tocopherol phosphate. There was a significant correlation between LDH-leakage and inhibition of fatty acid synthesis. Lipid peroxidation, measured as thiobarbituric acid-reactive substances, also showed a significant correlation with the degree of inhibition of fatty acid synthesis. Furthermore, PUFA had no inhibitory effect on fatty acid synthesis when peroxidation was minimized by the use of proper antioxidants. These data indicate that PUFA in vitro inhibit the insulin-induced de novo fatty acid synthesis in hepatocytes from starved rats, due to cytotoxic effects caused by lipid peroxidation.

  11. 76 FR 54791 - Polyethylene Terephthalate (PET) Film From Korea

    Science.gov (United States)

    2011-09-02

    ...731-TA-459; Third Review] Polyethylene Terephthalate (PET) Film From Korea...antidumping duty order on polyethylene terephthalate (PET) film from Korea...August 2011), entitled Polyethylene Terephthalate (PET) Film from...

  12. Cancer chemotherapy: targeting folic acid synthesis

    Directory of Open Access Journals (Sweden)

    Nicole Hagner

    2010-11-01

    Full Text Available Nicole Hagner, Markus JoergerDepartment of Medical Oncology, Cantonal Hospital, St Gallen, SwitzerlandAbstract: Antifolates are structural analogs of folates, essential one-carbon donors in the synthesis of DNA in mammalian cells. Antifolates are inhibitors of key enzymes in folate metabolism, namely dihydrofolate reductase, ?-glycinamide ribonucleotide transformylase, 5'-amino-4'-imidazolecarboxamide ribonucleotide transformylase, and thymidylate synthetase. Methotrexate is one of the earliest anticancer drugs and is extensively used in lymphoma, acute lymphoblastic leukemia, and osteosarcoma, among others. Pemetrexed has been approved in combination with cisplatin as first-line treatment for advanced non-squamous-cell lung cancer, as a single agent for relapsed non-small-cell lung cancer after platinum-containing chemotherapy, and in combination with cisplatin for the treatment of pleural mesothelioma. Raltitrexed is approved in many countries (except in the United States for advanced colorectal cancer, but its utilization is mainly limited to patients intolerant to 5-fluorouracil. Pralatrexate has recently been approved in the United States for relapsed or refractory peripheral T-cell lymphoma. This article gives an overview of the cellular mechanism, pharmacology, and clinical use of classical and newer antifolates and discusses some of the main resistance mechanisms to antifolate drugs.Keywords: antifolates, cancer, molecular pharmacology, pemetrexed, methotrexate, folate metabolism

  13. Aminolysis of polyethylene terephthalate surface along with in situ synthesis and stabilizing ZnO nanoparticles using triethanolamine optimized with response surface methodology.

    Science.gov (United States)

    Poortavasoly, Hajar; Montazer, Majid; Harifi, Tina

    2016-01-01

    This research concerned the simultaneous polyester surface modification and synthesis of zinc oxide nano-reactors to develop durable photo-bio-active fabric with variable hydrophobicity/hydrophilicity under sunlight. For this purpose, triethanolamine (TEA) was applied as a stabilizer and pH adjusting chemical for the aminolysis of polyester surface and enhancing the surface reactivity along with synthesis and deposition of ZnO nanoparticles on the fabric. Therefore, TEA played a crucial role in providing the alkaline condition for the preparation of zinc oxide nanoparticles and acting as stabilizer controlling the size of the prepared nanoparticles. The stain-photodegradability regarded as self-cleaning efficiency, wettability and weight change under the process was optimized based on zinc acetate and TEA concentrations, using central composite design (CCD). Findings also suggested the potential of the prepared fabric in inhibiting Staphylococcus aureus and Escherichia coli bacteria growth with greater than 99.99% antibacterial efficiency. Besides, the proposed treatment had no detrimental effect on tensile strength and hand feeling of the polyester fabric. PMID:26478337

  14. Cyclic Comonomers for the Synthesis of Carboxylic Acid and Amine Functionalized Poly(l-Lactic Acid

    Directory of Open Access Journals (Sweden)

    Markus Heiny

    2015-03-01

    Full Text Available Degradable aliphatic polyesters such as poly(lactic acid are widely used in biomedical applications, however, they lack functional moieties along the polymer backbone that are amenable for functionalization reactions or could be the basis for interactions with biological systems. Here we present a straightforward route for the synthesis of functional ?-? epoxyesters as comonomers for lactide polymerization. Salient features of these highly functionalized epoxides are versatility in functionality and a short synthetic route of less than four steps. The ?-? epoxyesters presented serve as a means to introduce carboxylic acid and amine functional groups into poly(lactic acid polymers via ring-opening copolymerization.

  15. Photochemical Synthesis of the Bioconjugate Folic Acid-Gold Nanoparticles

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Bertel, Linda

    2013-01-01

    In this paper we present a rapid and simple onepot method to obtain gold nanoparticles functionalized with folic acid using a photochemistry method. The bioconjugate folic acid-gold nanoparticle was generated in one step using a photo-reduction method, mixing hydrogen tetrachloroaurate with folic acid in different ratios and varying the illumination time of a mercury lamp (?= 255 nm). Scanning electron microscopy showed a particle size of around 40-50nm and dynamic light scattering exhibited that the zeta potential varies from -41 to -50mV with different illumination times. Storage in the dark at 4°C prolongs the stability of folic acid-gold nanoparticle suspensions to up to 26 days. Ultraviolet visible and Fourier transform infrared spectroscopy showed a surface plasmon band of around 534nm and fluorescence spectroscopy exhibited a quenching effect on gold nanoparticles in the fluorescence emission of folic acid and thus confirmed the conjugation of folic acid to the surface of gold nanoparticles. In this study we demonstrate the use of a photochemistry method to obtain folic acid-gold nanoparticles in a simple and rapid way without the use of surfactants and long reaction times. The photochemical synthesis of FA-AuNPs opens new perspectives for creating novel functional nanomaterials for biomedical applications.

  16. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    Directory of Open Access Journals (Sweden)

    M. Onciu

    2005-02-01

    Full Text Available Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP and pyridine (Py as bases and N-methyl-2-pyrolidinone (NMP as solvent, at reflux (180-190°C for 8-12 hours.

  17. Rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid

    DEFF Research Database (Denmark)

    Bunch, Lennart; Liljefors, Tommy; Greenwood, Jeremy R; Frydenvang, Karla Andrea; Bräuner-Osborne, Hans; Krogsgaard-Larsen, Povl; Madsen, Ulf

    2003-01-01

    The design and synthesis of conformationally restricted analogues of alpha-amino acids is an often used strategy in medicinal chemistry research. Here we present the rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid (1), a novel conformationally restricted (S)-glutamic acid (Glu) analogue intended as a mimic of the folded Glu conformation. The synthesis of 1 was completed in its racemic form in eight steps from commercially available sta...

  18. Synthesis and characterization of magnetite nanoparticles coated with lauric acid

    Energy Technology Data Exchange (ETDEWEB)

    Mamani, J.B., E-mail: javierbm@einstein.br [Instituto do Cérebro-InCe, Hospital Israelita Albert Einstein-HIAE, 05651-901 São Paulo (Brazil); Costa-Filho, A.J. [Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto (Brazil); Cornejo, D.R. [Instituto de Física Universidade de São Paulo, USP, São Paulo (Brazil); Vieira, E.D. [Instituto de Física, Universidade Federal de Goiás, Goiânia (Brazil); Gamarra, L.F. [Instituto do Cérebro-InCe, Hospital Israelita Albert Einstein-HIAE, 05651-901 São Paulo (Brazil)

    2013-07-15

    Understanding the process of synthesis of magnetic nanoparticles is important for its implementation in in vitro and in vivo studies. In this work we report the synthesis of magnetic nanoparticles made from ferrous oxide through coprecipitation chemical process. The nanostructured material was coated with lauric acid and dispersed in aqueous medium containing surfactant that yielded a stable colloidal suspension. The characterization of magnetic nanoparticles with distinct physico-chemical configurations is fundamental for biomedical applications. Therefore magnetic nanoparticles were characterized in terms of their morphology by means of TEM and DLS, which showed a polydispersed set of spherical nanoparticles (average diameter of ca. 9 nm) as a result of the protocol. The structural properties were characterized by using X-ray diffraction (XRD). XRD pattern showed the presence of peaks corresponding to the spinel phase of magnetite (Fe{sub 3}O{sub 4}). The relaxivities r{sub 2} and r{sub 2}* values were determined from the transverse relaxation times T{sub 2} and T{sub 2}* at 3 T. Magnetic characterization was performed using SQUID and FMR, which evidenced the superparamagnetic properties of the nanoparticles. Thermal characterization using DSC showed exothermic events associated with the oxidation of magnetite to maghemite. - Highlights: • Synthesis of magnetic nanoparticles coated with lauric acid • Characterization of magnetic nanoparticles • Morphological, structural, magnetic, calorimetric and relaxometric characterization.

  19. Synthesis and characterization of magnetite nanoparticles coated with lauric acid

    International Nuclear Information System (INIS)

    Understanding the process of synthesis of magnetic nanoparticles is important for its implementation in in vitro and in vivo studies. In this work we report the synthesis of magnetic nanoparticles made from ferrous oxide through coprecipitation chemical process. The nanostructured material was coated with lauric acid and dispersed in aqueous medium containing surfactant that yielded a stable colloidal suspension. The characterization of magnetic nanoparticles with distinct physico-chemical configurations is fundamental for biomedical applications. Therefore magnetic nanoparticles were characterized in terms of their morphology by means of TEM and DLS, which showed a polydispersed set of spherical nanoparticles (average diameter of ca. 9 nm) as a result of the protocol. The structural properties were characterized by using X-ray diffraction (XRD). XRD pattern showed the presence of peaks corresponding to the spinel phase of magnetite (Fe3O4). The relaxivities r2 and r2* values were determined from the transverse relaxation times T2 and T2* at 3 T. Magnetic characterization was performed using SQUID and FMR, which evidenced the superparamagnetic properties of the nanoparticles. Thermal characterization using DSC showed exothermic events associated with the oxidation of magnetite to maghemite. - Highlights: • Synthesis of magnetic nanoparticles coated with lauric acid • Characterization of magnetic nanoparticles • Morphological, structural, magnetic, calorimetric and relaxometric characterization

  20. A facile synthesis of ethyl 2-acetamido-4-methylenehex-5-enoate, a versatile Diels-Alder synthon for the parallel synthesis of novel alpha-amino acid derivatives

    OpenAIRE

    Chen, R; Lee, V; Adlington, RM; Baldwin, JE

    2007-01-01

    An efficient synthesis of a diene-containing ?-amino acid via the use of Denmark's coupling reaction and its application to the synthesis of novel ?-amino acid via the Diels-Alder reaction are described. © Georg Thieme Verlag Stuttgart.

  1. Increased Bile Acid Synthesis and Deconjugation After Biliopancreatic Diversion.

    Science.gov (United States)

    Ferrannini, Ele; Camastra, Stefania; Astiarraga, Brenno; Nannipieri, Monica; Castro-Perez, Jose; Xie, Dan; Wang, Liangsu; Chakravarthy, Manu; Haeusler, Rebecca A

    2015-10-01

    Biliopancreatic diversion (BPD) improves insulin sensitivity and decreases serum cholesterol out of proportion with weight loss. Mechanisms of these effects are unknown. One set of proposed contributors to metabolic improvements after bariatric surgeries is bile acids (BAs). We investigated the early and late effects of BPD on plasma BA levels, composition, and markers of BA synthesis in 15 patients with type 2 diabetes (T2D). We compared these to the early and late effects of Roux-en-Y gastric bypass (RYGB) in 22 patients with T2D and 16 with normal glucose tolerance. Seven weeks after BPD, insulin sensitivity had doubled and serum cholesterol had halved. At this time, BA synthesis markers and total plasma BAs, particularly unconjugated BAs, had markedly risen; this effect could not be entirely explained by low FGF19. In contrast, after RYGB, insulin sensitivity improved gradually with weight loss and cholesterol levels declined marginally; BA synthesis markers were decreased at an early time point (2 weeks) after surgery and returned to the normal range 1 year later. These findings indicate that BA synthesis contributes to the decreased serum cholesterol after BPD. Moreover, they suggest a potential role for altered enterohepatic circulation of BAs in improving insulin sensitivity and cholesterol metabolism after BPD. PMID:26015549

  2. Synthesis using alumina precursors subjected to acid attack

    International Nuclear Information System (INIS)

    Alumina is a material used in a wide range of applications, including refractories, structural materials, catalysts, sensors, etc.. Several synthetic methods are available for the production of sub-micrometer alpha alumina and nano, however, it is necessary to use special equipment or long synthesis times. Thus, this study aims the synthesis of alumina powders using a technique of treating their acid precursors. The precursors were obtained from the decomposition of aluminum acetate and the 650th 850 deg C, obtaining a precursor amorphous and gamma alumina. These materials were subjected to etching and ashing. Based on the results can be noted that the etching reduced the temperature of formation of alpha phase, yielding alpha alumina in the calcination temperature of 900 deg C. The etching was more effective in reducing the formation temperature alpha phase when using the amorphous precursor (author)

  3. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments.

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids. PMID:25796392

  4. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  5. Lactic acid demineralization of shrimp shell and chitosan synthesis

    Directory of Open Access Journals (Sweden)

    Alewo Opuada AMEH

    2015-05-01

    Full Text Available The use of lactic acid was compared to hydrochloric acid for shrimp shell demineralization in chitosan synthesis. Five different acid concentrations were considered for the study: 1.5M, 3.0M, 4.5M, 6.0M and 7.5M. After demineralization, the shrimp shell were deproteinized and subsequently deacetylated to produce chitosan using sodium hydroxide solution. The synthesized chitosan samples were characterized using solubility, FTIR, SEM, XRD and viscosity. The SEM, FTIR and XRD analysis indicated that chitosan was synthesized with a high degree of deacetylation (83.18±2.11 when lactic acid was used and 84.2±5.00 when HCl was used. The degree of deacetylation and the molecular weight of the chitosan samples were also estimated. ANOVA analysis (at 95% confidence interval indicated that acid type and concentration did not significantly affect the solubility, degree of deacetylation, viscosity and molecular weight of the chitosan within the range considered.

  6. Antimicrobial polyurethane thermosets based on undecylenic acid: synthesis and evaluation.

    Science.gov (United States)

    Lluch, Cristina; Esteve-Zarzoso, Braulio; Bordons, Albert; Lligadas, Gerard; Ronda, Juan C; Galià, Marina; Cádiz, Virginia

    2014-08-01

    In the present study, plant oil-derived surface-modifiable polyurethane thermosets are presented. Polyol synthesis is carried out taking advantage of thiol-yne photopolymerization of undecylenic acid derivatives containing methyl ester or hydroxyl moieties. The prepared methyl ester-containing polyurethanes allow surface modification treatment to enhance their hydrophilicity and impart antimicrobial activity through the following two steps: i) grafting poly(propylene glycol) monoamine (Jeffamine M-600) via aminolysis and ii) Jeffamine M-600 layer complexation with iodine. The antimicrobial activity of the iodine-containing polyurethanes is demonstrated by its capacity to inhibit the growth of Staphylococcus aureus, and Candida albicans in agar media. PMID:24799194

  7. Optimization of Butylphosphate synthesis from O-Phosphoric Acid

    International Nuclear Information System (INIS)

    This work was carried out in order to confirm results of previous work and to enhance the yield of TBP synthesis. This, many reactions have been realised under differents experimental condition (temperature, acid/ alcool molar ratio, pressure and the quantity of promoter agent 'POCL3'). the TBP yield variations as function the experimental parameters, has been expressed, using the 2n factorial plan mathematical model. The experimental results were compared to those given by the theoritical model, and the optimal conditions were then drawn out

  8. Modificação química de poli(tereftalato de etileno) pós-consumo por reação com ácido sulfúrico: estrutura e propriedades / Chemical modification of post consumer poly(ethylene terephthalate) by sulfuric acid reaction: structure and properties

    Scientific Electronic Library Online (English)

    Janaína G., Alonso; Elisabeth C., Molina; Edvani C., Muniz; Adley F., Rubira; Gizilene M. de, Carvalho.

    2005-03-01

    Full Text Available PET pós-consumo foi modificado quimicamente através de reação com ácido sulfúrico por diferentes tempos. O material modificado foi caracterizado por DSC e FTIR-PAS e XPS. Verificou-se que a intensidade relativa do isômero trans diminui enquanto do isômero gauche aumenta para tempos de reação entre 0 [...] e 60 minutos. Após 60 minutos de reação observou-se a presença de endotermas múltiplas que podem ser relacionadas com o desenvolvimento de estruturas intermediárias porque as intensidades relativas dos isômeros trans e gauche não apresentam variação significativa. O valor determinado de capacidade de troca iônica do PET pós-consumo modificado (PETS-pc) é comparável com os valores de resinas ácidas comerciais e não é afetado no intervalo de tempo de reação utilizado. Os valores da capacidade máxima de adsorção, qm, e do parâmetro de afinidade entre o adsorvente e o adsorvato, K, (111,18 ppm e 531,91 mg de corante/100g de adsorvente, respectivamente) para a adsorção do corante Remazol vermelho na amostra quimicamente modificada por 30 minutos foram calculados a partir da isoterma de adsorção de Langmuir. Os resultados indicam que esse material possui características adsorventes, podendo vir a ser utilizado para tratamento de efluente de indústria de tingimento têxtil. Abstract in english Chemical modification of post consumer PET was carried out by reaction with sulfuric acid. The modified material was characterized by DSC, XPS and FTIR-PAS measurements. The relative intensity of trans isomer increases while it decreases for gauche isomer for reaction times from 0 up to 60 min. Afte [...] r 60 minutes of reaction multiple endotherms were observed, which may be related to the development of an intermediated structure, since the relative intensities of the trans and gauche isomers do not change. The ionic exchange capacity of the modified post consumer poly(ethylene terephthalate), PETS-pc, is comparable to commercial acid resins and is not affected by the reaction time. The maximum adsorption capacity, qm, and the affinity parameter, K, (111.18 ppm and 531.91 mg dye/100g adsorvent, respectively) due to the adsorption of Remazol Red were calculated for PET samples chemically modified during 30 minutes from the Langmuir adsorption isotherms. The results indicate that PETS-pc has excellent adsorvent capacity, and can be applied to treatment of textile dye effluents.

  9. Modificação química de poli(tereftalato de etileno pós-consumo por reação com ácido sulfúrico: estrutura e propriedades Chemical modification of post consumer poly(ethylene terephthalate by sulfuric acid reaction: structure and properties

    Directory of Open Access Journals (Sweden)

    Janaína G. Alonso

    2005-03-01

    Full Text Available PET pós-consumo foi modificado quimicamente através de reação com ácido sulfúrico por diferentes tempos. O material modificado foi caracterizado por DSC e FTIR-PAS e XPS. Verificou-se que a intensidade relativa do isômero trans diminui enquanto do isômero gauche aumenta para tempos de reação entre 0 e 60 minutos. Após 60 minutos de reação observou-se a presença de endotermas múltiplas que podem ser relacionadas com o desenvolvimento de estruturas intermediárias porque as intensidades relativas dos isômeros trans e gauche não apresentam variação significativa. O valor determinado de capacidade de troca iônica do PET pós-consumo modificado (PETS-pc é comparável com os valores de resinas ácidas comerciais e não é afetado no intervalo de tempo de reação utilizado. Os valores da capacidade máxima de adsorção, qm, e do parâmetro de afinidade entre o adsorvente e o adsorvato, K, (111,18 ppm e 531,91 mg de corante/100g de adsorvente, respectivamente para a adsorção do corante Remazol vermelho na amostra quimicamente modificada por 30 minutos foram calculados a partir da isoterma de adsorção de Langmuir. Os resultados indicam que esse material possui características adsorventes, podendo vir a ser utilizado para tratamento de efluente de indústria de tingimento têxtil.Chemical modification of post consumer PET was carried out by reaction with sulfuric acid. The modified material was characterized by DSC, XPS and FTIR-PAS measurements. The relative intensity of trans isomer increases while it decreases for gauche isomer for reaction times from 0 up to 60 min. After 60 minutes of reaction multiple endotherms were observed, which may be related to the development of an intermediated structure, since the relative intensities of the trans and gauche isomers do not change. The ionic exchange capacity of the modified post consumer poly(ethylene terephthalate, PETS-pc, is comparable to commercial acid resins and is not affected by the reaction time. The maximum adsorption capacity, qm, and the affinity parameter, K, (111.18 ppm and 531.91 mg dye/100g adsorvent, respectively due to the adsorption of Remazol Red were calculated for PET samples chemically modified during 30 minutes from the Langmuir adsorption isotherms. The results indicate that PETS-pc has excellent adsorvent capacity, and can be applied to treatment of textile dye effluents.

  10. Synthesis of new indolecarboxylic acids related to the plant hormone indoleacetic acid IAA

    Directory of Open Access Journals (Sweden)

    Rosa Flávia A. F. da

    2003-01-01

    Full Text Available The synthesis of 5,6-methylenedioxy-indol-3-yl-methanoic acid 8 and 5,6-methylenedioxy-indol-3-yl-acetic acid 13 is described. Piperonal was employed as starting material, and the construction of the heterocyclic ring based on the Hemetsberger reaction of the corresponding beta-azidostyrene was highly regiospecific. Compound 8 was obtained as a key intermediate towards 13, and a Mannich reaction was used to introduce the required alkyl side chain. The route comprised eight steps giving 13 in 26% overall yield. The formation of the indolic ring via reductive cyclisation of o,beta-dinitrostyrene is also presented.

  11. Synthesis of a conformationally constrained delta-amino acid building block

    OpenAIRE

    O'Reilly, Elaine; Pes, Lara; Ortin, Yannick; Mueller-Bunz, Helge; Paradisi, Francesca

    2013-01-01

    Conformationally restricted amino acids are important components in peptidomimetics and drug design. Herein, we describe the synthesis of a novel, non-proteinogenic constrained delta amino acid containing a cyclobutane ring, cis-3(aminomethyl)cyclobutane carboxylic acid (ACCA). The synthesis of the target amino acid was achieved in seven steps, with the key reaction being a base induced intramolecular nucleophilic substitution. A small library of dipeptides was prepared through the coupling o...

  12. Synthesis and electrochemical behaviour of beta-halodehydroamino acid derivatives.

    Science.gov (United States)

    Ferreira, Paula M T; Monteiro, L S; Pereira, G

    2010-07-01

    Several new beta,beta-dihalo and beta-halo-beta-substituted dehydroalanines and dehydrodipeptides were synthesized by reacting the corresponding dehydroamino acid derivative with a N-halosuccinimide or in the case of beta,beta-di-iododehydroalanines with iodine. The results obtained confirmed that the stereochemical outcome of the halogenation reaction with beta-substituted dehydroamino acids depends on the substrate. Thus, an increase Z-stereoselectivity was found when the beta-phenyldehydroalanines were used as substrates and when these compounds were N-protected with 4-tolylsulfonyl or with carbamates. From this study, it is also possible to conclude that when N-iodosuccinimide was used as reagent a much higher Z-stereoselectivity is found. The electrochemical behaviour of the halogenated dehydroamino acids was studied by cyclic voltammetry. The results show a shift in the reduction peak to higher potentials of the beta-halogenated dehydroamino acids when compared with the corresponding non-halogenated derivatives. As expected, the beta,beta-dihalodehydroalanines exhibit higher peak potentials than beta-halo-beta-substituted dehydroalanines and the bromo derivatives have lower peak potentials when compared with the corresponding iododehydroamino acids. Controlled potential electrolysis of several beta-halo-beta-substituted dehydroamino acids afforded the corresponding dehalogenated dehydroamino acids as mixtures of their E and Z-isomers. In all cases, the major isomer isolated results from dehalogenation without isomerization. These new results show that electrochemical reduction constitutes a valuable method for the synthesis of the E-isomer of beta-substituted dehydroalanines. PMID:20195660

  13. Synthesis and conductivity of heptadecatungstovanadodiphosphoric heteropoly acid with Dawson structure

    International Nuclear Information System (INIS)

    A new solid high-proton conductor, heptadecatungstovanadodiphosphoric heteropoly acid H7P2W17VO62.28H2O with Dawson structure was synthesized by the stepwise acidification and the stepwise addition of element solutions. The optimal proportion of component compounds in the synthesis reaction was given. The product was characterized by chemical analysis, potentiometric titration, IR, UV, XRD, 31P NMR, TG-DTA and electrochemical impedance spectroscopy (EIS). The results indicate that H7P2W17VO62.28H2O possesses the Dawson structure. EIS measurements show a high conductivity (3.10 x 10-2 S cm-1 at 26 deg. C and 75% relative humidity), with an activation energy of 32.23 kJ mol-1 for proton conduction. The mechanism of proton conduction for this heteropoly acid is Vehicle mechanism.

  14. AMINO ACIDS AUGMENT MUSCLE PROTEIN SYNTHESIS IN NEONATAL PIGS DURING ENDOTOXEMIA BY MODULATING TRANSLATION INITIATION

    Science.gov (United States)

    In adults, sepsis reduces protein synthesis in skeletal muscle by restraining translation. The effect of sepsis on amino acid-stimulated muscle protein synthesis has not been determined in neonates, a population who is highly anabolic and whose muscle protein synthesis rates are uniquely sensitive ...

  15. Helicobacter pylori utilises urea for amino acid synthesis.

    Science.gov (United States)

    Williams, C L; Preston, T; Hossack, M; Slater, C; McColl, K E

    1996-01-01

    Helicobacter pylori has one of the highest urease activities of all known bacteria. Its enzymatic production of ammonia protects the organism from acid damage by gastric juice. The possibility that the urease activity allows the bacterium to utilise urea as a nitrogen source for the synthesis of amino acids was investigated. H. pylori (NCTC 11638) was incubated with 50 mM urea, enriched to 5 atom% excess 15N, that is the excess enrichment of 15N above the normal background, in the presence of either NaCl pH 6.0, or 0.2M citrate pH 6.0. E. coli (NCTC 9001) was used as a urease-negative control. 15N enrichment was detected by isotope ratio mass spectrometry. H. pylori showed intracellular incorporation of 15N in the presence of citrate buffer pH 6.0 but there was no significant incorporation of 15N in unbuffered saline or by E. coli in either pH 6.0 citrate buffer or unbuffered saline. The intracellular fate of the urea-nitrogen was determined by means of gas chromatography/mass spectrometry following incubation with 15N enriched 5 mM urea in the presence of either 0.2 M citrate buffer pH 6.0 or 0.2 M acetate buffer pH 6.0. After 5 min incubation in either buffer the 15N label appeared in glutamate, glutamine, phenylalanine, aspartate and alanine. It appears, therefore, that at pH and urea concentrations typical of the gastric mucosal surface, H. pylori utilises exogenous urea as a nitrogen source for amino acid synthesis. The ammonia produced by H. pylori urease activity thus facilitates the organism's nitrogen metabolism at neutral pH as well as protecting it from acid damage at low pH. PMID:8821403

  16. Alternative kynurenic acid synthesis routes studied in the rat cerebellum

    Directory of Open Access Journals (Sweden)

    Liliana Aparicio Carmona

    2015-05-01

    Full Text Available Kynurenic acid (KYNA, an astrocyte-derived, endogenous antagonist of ?7 nicotinic acetylcholine and excitatory amino acid receptors, regulates glutamatergic, GABAergic, cholinergic and dopaminergic neurotransmission in several regions of the rodent brain. Synthesis of KYNA in the brain and elsewhere is generally attributed to the enzymatic conversion of L-kynurenine (L-KYN by kynurenine aminotransferases (KATs. However, alternative routes, including KYNA formation from D-kynurenine (D-KYN by D-amino acid oxidase (DAAO and the direct transformation of kynurenine to KYNA by reactive oxygen species (ROS, have been demonstrated in the rat brain. Using the rat cerebellum, a region of low KAT activity and high DAAO activity, the present experiments were designed to examine KYNA production from L-KYN or D-KYN by KAT and DAAO, respectively, and to investigate the effect of ROS on KYNA synthesis. In chemical combinatorial systems, both L-KYN and D-KYN interacted directly with peroxynitrite (ONOO- and hydroxyl radicals (OH•, resulting in the formation of KYNA. In tissue homogenates, the non-specific KAT inhibitor aminooxyacetic acid (AOAA; 1 mM reduced KYNA production from L-KYN and D-KYN by 85.1 ± 1.7% and 27.1 ± 4.5%, respectively. Addition of DAAO inhibitors (benzoic acid, kojic acid or 3-methylpyrazole-5-carboxylic acid; 5 µM each attenuated KYNA formation from L-KYN and D-KYN by ~35% and ~66%, respectively. ONOO- (25 µM potentiated KYNA production from both L-KYN and D-KYN, and these effects were reduced by DAAO inhibition. AOAA attenuated KYNA production from L-KYN + ONOO- but not from D-KYN + ONOO-. In vivo, extracellular KYNA levels increased rapidly after perfusion of ONOO- and, more prominently, after subsequent perfusion with L-KYN or D-KYN (100 µM. Taken together, these results suggest that different mechanisms are involved in KYNA production in the rat cerebellum, and that, specifically, DAAO and ROS can function as alternative routes for KYNA produc

  17. Synthesis and immunological characterization of modified hyaluronic acid hexasaccharide conjugates.

    Science.gov (United States)

    Gu, Guofeng; Adabala, Pal John Pal; Szczepina, Monica G; Borrelli, Silvia; Pinto, B Mario

    2013-08-16

    The synthesis of a tetanus toxoid (TT)-conjugate of a hyaluronic acid (HA) hexasaccharide is described. The compound was intended for use in monitoring HA levels as a disease marker and as a potential vaccine against Group A Streptococcus (GAS) infections. We also report the synthesis of a chemically modified HA-hexasaccharide-TT conjugate in which the N-acetyl moiety of the N-acetyl-D-glucosamine residue is replaced with an N-propionyl unit in order to enhance immunogenicity. The oligosaccharides are synthesized in a convergent manner. The TT-conjugate syntheses rely on the reaction of the amines on the 6-aminohexyl aglycon of the hexasaccharides with diethyl squarate to give the monoethyl squarate adducts. Subsequent reactions with lysine ?-amino groups on TT then give the glycoconjugates containing an average of 8 hexasaccharide haptens per TT molecule. Immunological studies in mice show very similar antibody responses with both conjugates, suggesting that the N-acetyl groups of the glucosaminyl residues of the HA-hexasaccharide are not a critical part of the epitope recognized by the anti-HA polyclonal immune response. Furthermore, it would appear that the N-acyl moieties are not in close contact with the amino acid residues of the antibody combining sites. PMID:23848545

  18. Synthesis of a stable gold hydrosol by the reduction of chloroaurate ions by the amino acid, aspartic acid

    Indian Academy of Sciences (India)

    Saikat Mandal; P R Selvakannan; Sumant Phadtare; Renu Pasricha; Murali Sastry

    2002-10-01

    Development of reliable protocols for the synthesis of nanoparticles of well-defined sizes and good monodispersity is an important aspect of nanotechnology. In this paper, we present details of the synthesis of gold nanoparticles of good monodispersity by the reduction of aqueous chloroaurate ions by the amino acid, aspartic acid. The colloidal gold solution thus formed is extremely stable in time, indicating electrostatic stabilization via nanoparticle surface-bound amino acid molecules. This observation has been used to modulate the size of the gold nanoparticles in solution by varying the molar ratio of chloroaurate ions to aspartic acid in the reaction medium. Characterization of the aspartic acid-reduced gold nanoparticles was carried out by UV-visible spectroscopy, thermogravimetric analysis and transmission electron microscopy. The use of amino acids in the synthesis and stabilization of gold nanoparticle in water has important implications in the development of new protocols for generation of bioconjugate materials.

  19. ETBE synthesis over silicotungstic acid and tungstophosphoric acid catalysts calcined at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Degirmenci, Levent; Oktar, Nuray; Dogu, Gulsen [Department of Chemical Engineering, Gazi University, 06570 Maltepe, Ankara (Turkey)

    2010-07-15

    Vapor phase ethyl tertiary butyl ether synthesis was investigated using heat treated heteropoly acid catalysts, namely silicotungtsic acid (STA) and tungstophosphoric acid-Keggin (TPA-K) and these results were compared with the results obtained with untreated catalysts. ETBE synthesis experiments showed that heat treatment of TPA-K at temperatures over 473 K had caused significant decrease of its catalytic activity. Activity of STA was more stable and deactivation of this catalyst was observed by heat treatment at 673 K and above. Heat treatment at high temperatures caused loss of constitutional water of STA and TPA-K, causing loss of protons, consequently the loss of acidity of the catalysts, resulting deactivation. FT-IR, TGA-DTA and DRIFTS analyses on pyridine-adsorbed catalysts supported the conclusions related to structural changes of STA and TPA-K with heat treatment. Highest ETBE yields were obtained at around 368 K, while at temperatures over 423 K formation of DEE and ethylene were observed due to dehydration of ethanol. (author)

  20. Effect of uncoated calcium carbonate and stearic acid coated calcium carbonate on mechanical, thermal and structural properties of poly(butylene terephthalate) (PBT)/calcium carbonate composites

    Indian Academy of Sciences (India)

    G S Deshmukh; S U Pathak; D R Peshwe; J D Ekhe

    2010-06-01

    PBT/CaCO3 composites were prepared in a single screw extruder with particle content varying from 0–30% by weight. The influence of surface treatment of the particles, with and without stearic acid (SA), on the mechanical, thermal and structural properties was studied. The experiments included tensile tests, impact tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy. The composite systems containing SA coated CaCO3 were found to exhibit better mechanical properties as compared to composite systems containing uncoated CaCO3, with the S3 system (20% of SA coated CaCO3) exhibiting best combination of mechanical properties. Thermal study revealed that particle type and content had no influence on the melting temperature but the crystallization temperature, % crystallinity and thermal stability increased on increasing the CaCO3 content in PBT matrix. Morphological observation indicated that in PBT composites containing SA coated CaCO3, the coupling agent favours a better polymer filler interaction rendering inorganic polymer interface compatible, which is also evident from better mechanical and thermal properties.

  1. Synthesis of decapeptide of L-aspartic acid and benzyl-L-aspartic acid by solid phase peptide synthesis.

    Science.gov (United States)

    Yoo, Bong K; Miah, M A Jalil; Lee, Eung-Seok; Han, Kun

    2005-07-01

    Polyene macrolide amphotericin B (AmB) is the drug of choice for the treatment of disseminated fungal infections. However, because of its pronounced side effects, the drug has limited applicability. There are few interesting reports, which state that co-administration of the drug with homo-peptide of polyaspartic acid reduces the side effects of the drug. In our present study, an approach has been made to systematically synthesize low molecular weight heteropeptides consisting of L-aspartic acid and its derivative. It was hypothesized that such heteropeptides will reduce the toxic side effects of the drug by facile hydrophobic binding between the polymer and the drug. We have employed the strategy of solid phase peptide synthesis (SPPS) to synthesize low molecular weight hetero-peptides by using L-aspartic acid and benzyl-L-aspartic acid to induce the hydrophobic binding between the peptide and the drug. In future, the proposed methodology can be employed to tailor other polypeptides substituted with benzyl groups to reduce the nephrotoxicity of AmB. PMID:16114487

  2. Expression of fatty acid synthesis genes and fatty acid accumulation in haematococcus pluvialis under different stressors

    Directory of Open Access Journals (Sweden)

    Lei Anping

    2012-03-01

    Full Text Available Abstract Background Biofuel has been the focus of intensive global research over the past few years. The development of 4th generation biofuel production (algae-to-biofuels based on metabolic engineering of algae is still in its infancy, one of the main barriers is our lacking of understanding of microalgal growth, metabolism and biofuel production. Although fatty acid (FA biosynthesis pathway genes have been all cloned and biosynthesis pathway was built up in some higher plants, the molecular mechanism for its regulation in microalgae is far away from elucidation. Results We cloned main key genes for FA biosynthesis in Haematococcus pluvialis, a green microalga as a potential biodiesel feedstock, and investigated the correlations between their expression alternation and FA composition and content detected by GC-MS under different stress treatments, such as nitrogen depletion, salinity, high or low temperature. Our results showed that high temperature, high salinity, and nitrogen depletion treatments played significant roles in promoting microalgal FA synthesis, while FA qualities were not changed much. Correlation analysis showed that acyl carrier protein (ACP, 3-ketoacyl-ACP-synthase (KAS, and acyl-ACP thioesterase (FATA gene expression had significant correlations with monounsaturated FA (MUFA synthesis and polyunsaturated FA (PUFA synthesis. Conclusions We proposed that ACP, KAS, and FATA in H. pluvialis may play an important role in FA synthesis and may be rate limiting genes, which probably could be modified for the further study of metabolic engineering to improve microalgal biofuel quality and production.

  3. Synthesis of esters of 3 A, 7 A, 12 A-three ketocholanic acid

    International Nuclear Information System (INIS)

    The synthesis of esters of 3 A, 7 A, 12 A-three ketocholanic acid was carried out. Their structure and purity were defined by means of infrared-spectroscopy and gas chromatography. The initial 3 A, 7 A, 12 A-three ketocholanic acid was the object of investigation. Methyl, ethyl, propyl, isopropyl, and butyl alcohols were used for synthesis of esters of 3 A, 7 A, 12 A-three ketocholanic acid.

  4. Kinetic resolution and stereoselective synthesis of 3-substituted aspartic acids by using engineered methylaspartate ammonia lyases.

    Science.gov (United States)

    Raj, Hans; Szymanski, Wiktor; de Villiers, Jandré; Puthan Veetil, Vinod; Quax, Wim J; Shimamoto, Keiko; Janssen, Dick B; Feringa, Ben L; Poelarends, Gerrit J

    2013-08-19

    Enzymatic amino acid synthesis: Kinetic resolution and asymmetric synthesis of various valuable 3-substituted aspartic acids, which were obtained in fair to good yields with diastereomeric ratio values of up to >98:2 and enantiomeric excess values of up to >99?%, by using engineered methylaspartate ammonia lyases are described. These biocatalytic methodologies for the selective preparation of aspartic acid derivatives appear to be attractive alternatives for existing chemical methods. PMID:23852946

  5. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    OpenAIRE

    Xuezheng Liang; Shao-Qin Lv; Lin-Mei Rong; Sheng-Xian Zhao; Chunqing Li; Baowei Hu; Chenze Qi

    2010-01-01

    The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols ...

  6. Synthesis and pharmacokinetic profile of rhein- boswellic acid conjugate.

    Science.gov (United States)

    Suneela, Dhaneshwar; Dipmala, Patil

    2012-12-15

    Rhein, an active metabolite of diacerein, down-regulates the gene-expression and production of pro-matrix metalloproteinases and up-regulates the tissue inhibitors of metalloproteinase-1 production. The therapeutic effects of diacerein on osteoarthritis are, at least in part, due to the chondroprotective effect of rhein. Boswellic acid is a specific, non-redox inhibitor of leukotriene synthesis. It is claimed to possess good anti-inflammatory, anti-arthritic, analgesic, and anti-ulcer activities. It prevents the destruction of articular cartilage by decreasing degradation of glycosaminoglycans. Therefore, rhein and boswellic acid were linked chemically through a bioreversible ester linkage to synthesize their mutual prodrug by reported procedure. In vitro release profile of this prodrug was extensively studied in aqueous buffers of varied pH, upper GIT homogenates and 80% human plasma. In vivo release studies were undertaken in blood, urine and feces of rats. The prodrug was stable in HCl buffer (pH 1.2) and stomach homogenates of rats. However; in phosphate buffer (pH 7.4) and in intestinal homogenates the prodrug exhibited 91% and 96% release of rhein and 27.5% and 38% release of boswellic acid respectively over a period of 6h following first order kinetics. In 80% human plasma (in vitro) and rat blood (in vivo) also 96.35% and 91% release of rhein and 78% and 86.41% release of boswellic acid respectively was observed. The 24 h pooled samples of rat urine revealed presence of 6.2% intact prodrug, 7.1% of rhein and 8.9% of boswellic acid indicating their renal excretion. Samples of rat feces pooled over a period of 24 h showed absence of rhein and presence of 3.1% of intact boswellic acid and 4.6% of boswellic acid emphasizing their intestinal excretion. The in vivo release kinetics of prodrug in rat clearly indicated activation of prodrug to be occurring in blood, being catalyzed by the weak alkaline pH of blood (7.4) in combination with esterases present therein. PMID:23107483

  7. Role of phosphatidic acid in plant galactolipid synthesis.

    Science.gov (United States)

    Dubots, Emmanuelle; Botté, Cyrille; Boudière, Laurence; Yamaryo-Botté, Yoshiki; Jouhet, Juliette; Maréchal, Eric; Block, Maryse A

    2012-01-01

    Phosphatidic acid (PA) is a precursor metabolite for phosphoglycerolipids and also for galactoglycerolipids, which are essential lipids for formation of plant membranes. PA has in addition a main regulatory role in a number of developmental processes notably in the response of the plant to environmental stresses. We review here the different pools of PA dispatched at different locations in the plant cell and how these pools are modified in different growth conditions, particularly during plastid membrane biogenesis and when the plant is exposed to phosphate deprivation. We analyze how these modifications can affect galactolipid synthesis by tuning the activity of MGD1 enzyme allowing a coupling of phospho- and galactolipid metabolisms. Some mechanisms are considered to explain how physicochemical properties of PA allow this lipid to act as a central internal sensor in plant physiology. PMID:21501653

  8. Incorporation of Isosorbide into Poly(butylene terephthalate) via Solid-State Polymerization

    OpenAIRE

    Sablong, R.J.; Duchateau, R; Konings, C.E.; Wit, G. de; Es, D.S., van; Koelewijn, R; Van Haveren, J.

    2008-01-01

    The biomass-based monomer isosorbide was incorporated into poly(butylene terephthalate) (PBT) by solid-state polymerization (SSP) using the macrodiol monomer BTITB-(OH)2, which consists of isosorbide (I), terephthalic acid (T), and 1,4-butandiol (B) residues. This macromonomer can be synthesized by a simple one-pot, two-step reaction. Polymers with number-average molecular weights up to 100 000 g·mol¿1 were readily synthesized from various ratios of PBT/BTITB-(OH)2. Their molecular weights, t...

  9. Enzymatic synthesis and application of fatty acid ascorbyl esters

    Directory of Open Access Journals (Sweden)

    Stojanovi? Marija M.

    2013-01-01

    Full Text Available Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully used as a reaction medium, since commonly used solvents with high Log P values are inapplicable due to ascorbic acid high polarity. Acylation of vitamin C using fatty acids, their methyl-, ethyl-, and vinyl esters, as well as triglycerides has been performed, whereas application of the activated acyl donors enabled higher molar conversions. In each case, majority of authors reported that using excessive amount of the acyl donor had positive effect on yield of product. Furthermore, several strategies have been employed for shifting the equilibrium towards the product by water content control. These include adjusting the initial water activity by pre-equilibration of reaction mixture, enzyme preparation with water vapor of saturated salt solutions, and the removal of formed water by the addition of molecular sieves or salt hydrate pairs. The aim of this article is to provide a brief overview of the procedures described so far for the lipase-catalyzed synthesis of fatty acid ascorbyl esters with emphasis on the potential application in food, cosmetics, and pharmaceutics. Furthermore, it has been pointed out that the main obstacles for process commercialization are long reaction times, lack of adequate purification methods, and high costs of lipases. Thus, future challenges in this area are testing new catalysts, developing continuous processes for esters production, finding cheaper acyl donors and reaction mediums, as well as identifying standard procedures for purification of products which will not require consumption of large amounts of non-biocompatible organic solvents.

  10. Fatty Acid Biosynthesis IX. : Fatty Acid Synthesis from Enzymically and Chemically Acetylated Rabbit Mammary Gland Fatty Acid Synthetase.

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids. Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles of acetate were bound per mole of fatty acid synthetase, with 20–25 moles being bound to thiol groups per mole of enzyme. Acylation did not inhibit enzyme activity. The majority of the bound acetate was stable to hydrolysis at o °C. Out of the 60 moles of acetate bound per mole of acetylated enzyme, up to 20 moles were incorporated into fatty acids in the presence of malonyl-CoA and NADPH. # 4. 4. Due to the rapid hydrolysis of acetyl-fatty acid synthetase prepared from both acetyl-CoA and acetic anhydride, direct carboxylation of acetyl-fatty acid synthetase to form malonyl-fatty acid synthetase could not be demonstrated by CO2 fixation under the experimental conditions used. With acetic anhydride as acetyl donor, there was a low rate of incorporation of acetate into fatty acids in the presence of NADPH but absence of added malonyl-CoA. This could be due to direct carboxylation of the acetate bound to fatty acid synthetase or, if any CoA were associated with the fatty acid synthetase, to carboxylation of acetyl-CoA formed by chemical acetylation of this CoA.

  11. Synthesis of Diaminopimelic Acid, Lysine and Pipecolic Acid from Spartic Acid by Rumen Microorganisms

    OpenAIRE

    A.M. El-Waziry

    2012-01-01

    The current study was examined the formation of the three Stereoisomers (SI) of 2, 6-Diaminopimelic Acid (DAP), lysine and pipecolic acid from aspartic acid by mixed rumen bacteria and protozoa. Mixed rumen bacteria and protozoa were isolated from the rumen of sheep given concentrate mixture and hay and incubated with and without aspartic acid (5 mM). The microbial suspensions were anaerobically incubated at 39°C for 12 h. The results showed that mixed rumen bacteria produced meso-DAP by 0.22...

  12. An effective one-pot synthesis of 5-substituted tetronic acids

    OpenAIRE

    Tejedor Aragón, David; López, Gloria V.; García-Tellado, Fernando; Marrero-Tellado, José Juan; De Armas, Pedro; Terrero, David

    2003-01-01

    An expeditions one-pot synthesis of 5-substituted tetronic acids from aldehydes and terminal conjugated alkyne as starting materialñs is described. THe entire process embodies two consecutive chemical events; a catalytic domino reaction to build the 1,3-dioxolane scaffolds 5 and a two-step acid-catalyzed trans-acetalization-lactonization reaction to furnish the tetronic acid derivatives 6.

  13. Synthesis of new polyphosphonic acids, uranium extracting agents in a phosphoric medium

    International Nuclear Information System (INIS)

    Synthesis of organic phosphorus compounds for liquid-liquid extraction of traces of uranium in concentrated phosphoric acid is studied in view of industrial applications. Diphosphonic acids and monoesters and also triphosphonic acids and related compounds are synthetized. Extraction tests show a better efficiency than OPPA

  14. Synthesis of hyaluronic acid oligosaccharides and exploration of a fluorous-assisted approach

    OpenAIRE

    Macchione, Giuseppe; de Paz, José L; Pedro M. Nieto

    2014-01-01

    The synthesis of hyaluronic acid oligomers (tri- and tetrasaccharide) is described. We have followed a pre-glycosylation oxidation strategy. Glucuronic acid units were directly employed in coupling reactions with suitably protected glucosamine derivatives. In order to simplify the puri?cation of synthetic intermediates, a ?uorous-assisted strategy has been also explored. Using this approach, a hyaluronic acid trisaccharide was prepared.

  15. Isolation, structure, and synthesis of viridic acid, a new tetrapeptide mycotoxin of Penicillium viridicatum Westling

    International Nuclear Information System (INIS)

    The isolation of a new toxic metabolite, viridic acid, from Penicillium viridicatum Westling is described. The chemical and spectroscopic properties of the compound are interpreted in terms of the tetrapeptide structure (N,N-dimethyl-o-aminobenzoyl)-glycyl-(N'-methyl-L-valyl)-o-aminobenzoic acid. The structure and chirality of viridic acid were confirmed by total synthesis

  16. Synthesis of dihydropyrimidine ?,?-diketobutanoic acid derivatives targeting HIV integrase.

    Science.gov (United States)

    Sari, Ozkan; Roy, Vincent; Métifiot, Mathieu; Marchand, Christophe; Pommier, Yves; Bourg, Stéphane; Bonnet, Pascal; Schinazi, Raymond F; Agrofoglio, Luigi A

    2015-11-01

    The synthesis and antiviral evaluation of a series of dihydropyrimidinone and thiopyrimidine derivatives bearing aryl ?,?-diketobutanoic acid moiety are described using the Biginelli multicomponent reaction as key step. The most active among 20 synthesized novel compounds were 4c, 4d and 5b, which possess nanomolar HIV-1 integrase (IN) stand transfer (ST) inhibition activities. In order to understand their mode of interactions within the IN active site, we docked all the compounds into the previously reported X-ray crystal structure of IN. We observed that compounds 4c, 4d and 5b occupied an area close to the two catalytic Mg(2+) ions surrounded by their chelating triad (E221, D128 and D185), DC16, Y212 and the ?-diketo acid moiety of 4c, 4d and 5b chelating Mg(2+). As those compounds lack anti-HIV activities in cell, their prodrugs were synthetized. The prodrug 4c' exhibited an anti-HIV activity of 0.19 ?M in primary human lymphocytes with some cytotoxicity. All together, these results indicate that the new analogs potentially interact within the catalytic site with highly conserved residues important for IN catalytic activity. PMID:26451771

  17. The selective generation of acetic acid directly from synthesis gas

    International Nuclear Information System (INIS)

    The authors conclude that each of the ruthenium, cobalt and iodide-containing catalyst components have very specific roles to play in the ''melt'' catalyzed conversion of synthesis gas to acetic acid. C1-Oxygenate formation is only observed in the presence of ruthenium carbonyls - [Ru(CO)3I3]- is here the dominant species - and there is a direct relationship between liquid yield, ?OAc-productivity and [Ru(CO)3I3]- content. Controlled quantities of iodide ensure that initially formed MeOH is rapidly converted to the more reactive methyl iodide. Subsequent cobalt-catalyzed carbonylation to acetic acid may be preparatively attractive (>80% selectivity, good yields) relative to competing syntheses, where the [Co(CO)4]- concentration is maximized that is, where the Co/Ru ratio is >1, the syngas feedstock is rich in CO, and the initial iodide/cobalt ratios are ca. unity. Formation of cobalt-iodide species appears to be a competing, inhibitory step in this catalysis

  18. Synthesis and conductivity of heptadecatungstovanadodiphosphoric heteropoly acid with Dawson structure

    Energy Technology Data Exchange (ETDEWEB)

    Tong Xia; Zhu Weiming [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Wu Qingyin, E-mail: qywu@zju.edu.cn [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Qian Xueyu; Liu Zhen [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Yan Wenfu [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012 (China); Gong Jian [Key Lab of Polyoxometalate Science, the Ministry of Education, Northeast Normal University, Changchun 130024 (China)

    2011-07-21

    A new solid high-proton conductor, heptadecatungstovanadodiphosphoric heteropoly acid H{sub 7}P{sub 2}W{sub 17}VO{sub 62}.28H{sub 2}O with Dawson structure was synthesized by the stepwise acidification and the stepwise addition of element solutions. The optimal proportion of component compounds in the synthesis reaction was given. The product was characterized by chemical analysis, potentiometric titration, IR, UV, XRD, {sup 31}P NMR, TG-DTA and electrochemical impedance spectroscopy (EIS). The results indicate that H{sub 7}P{sub 2}W{sub 17}VO{sub 62}.28H{sub 2}O possesses the Dawson structure. EIS measurements show a high conductivity (3.10 x 10{sup -2} S cm{sup -1} at 26 deg. C and 75% relative humidity), with an activation energy of 32.23 kJ mol{sup -1} for proton conduction. The mechanism of proton conduction for this heteropoly acid is Vehicle mechanism.

  19. Synthesis of fatty acid sterol esters using cholesterol esterase from Trichoderma sp. AS59.

    Science.gov (United States)

    Morinaga, Naoya; Maeda, Atsushi; Mizuno, Takayuki; Bunya, Masanori; Sugihara, Shigeo; Sugihara, Akio

    2011-05-01

    We recently reported the characterization of novel cholesterol esterase (EC. 3.1.1.13) from Trichoderma sp. and preliminary work on sterol ester synthesis. In the present study, we further examined the enzyme ability to synthesize cholesterol esters from cholesterol and free fatty acids of various chain lengths, and compared the fatty acid specificity in synthesis with that in hydrolysis. The enzyme catalyzed the synthesis of medium- and long-chain fatty acid cholesterol esters, but failed to synthesize short-chain fatty acid esters. The fatty acid specificities in the synthesis and hydrolysis of cholesterol esters were entirely different from each other. Unlike other lipolytic enzymes, the enzyme was largely independent of water content in the synthesis of cholesterol oleate, and it achieved near-complete esterification in the presence of an equimolar excess of oleic acid. Of additional interest is the finding that the addition of n-hexane markedly enhanced the esterification activities on all the medium- and long-chain saturated fatty acids used. Based on these findings, we attempted to synthesize stigmasterol stearate as a food additive to lower cholesterol levels in blood plasma, and found that the enzyme catalyzed effective synthesis of the ester without the need of dehydration during the reaction, indicating the potential utility of the enzyme in the food industry. PMID:22113022

  20. Synthesis of fluorescent D-amino acids (FDAAs) and their use for probing peptidoglycan synthesis and bacterial growth in situ

    OpenAIRE

    Kuru, Erkin; Tekkam, Srinivas; Hall, Edward; Brun, Yves V; VanNieuwenhze, Michael S.

    2014-01-01

    Fluorescent D-amino acids (FDAAs) are efficiently incorporated into the peptidoglycan of diverse bacterial species at the sites of active peptidoglycan biosynthesis, allowing specific and covalent probing of bacterial growth with minimal perturbation. Here, we provide a protocol for the synthesis of four FDAAs emitting light in blue, green or red and for their use in peptidoglycan labeling of live bacteria. Our modular synthesis protocol gives easy access to a library of different FDAAs made ...

  1. Synthesis of L-ascorbic acid in the phloem

    Directory of Open Access Journals (Sweden)

    Haupt Sophie

    2003-11-01

    Full Text Available Abstract Background Although plants are the main source of vitamin C in the human diet, we still have a limited understanding of how plants synthesise L-ascorbic acid (AsA and what regulates its concentration in different plant tissues. In particular, the enormous variability in the vitamin C content of storage organs from different plants remains unexplained. Possible sources of AsA in plant storage organs include in situ synthesis and long-distance transport of AsA synthesised in other tissues via the phloem. In this paper we examine a third possibility, that of synthesis within the phloem. Results We provide evidence for the presence of AsA in the phloem sap of a wide range of crop species using aphid stylectomy and histochemical approaches. The activity of almost all the enzymes of the primary AsA biosynthetic pathway were detected in phloem-rich vascular exudates from Cucurbita pepo fruits and AsA biosynthesis was demonstrated in isolated phloem strands from Apium graveolens petioles incubated with a range of precursors (D-glucose, D-mannose, L-galactose and L-galactono-1,4-lactone. Phloem uptake of D-[U-14C]mannose and L-[1-14C]galactose (intermediates of the AsA biosynthetic pathway as well as L-[1-14C]AsA and L-[1-14C]DHA, was observed in Nicotiana benthamiana leaf discs. Conclusions We present the novel finding that active AsA biosynthesis occurs in the phloem. This process must now be considered in the context of mechanisms implicated in whole plant AsA distribution. This work should provoke studies aimed at elucidation of the in vivo substrates for phloem AsA biosynthesis and its contribution to AsA accumulation in plant storage organs.

  2. Templated synthesis of nylon nucleic acids and characterization by nuclease digestion

    OpenAIRE

    Liu, Yu; Wang, Risheng; DING, Liang; Sha, Roujie; Seeman, Nadrian C.; Canary, James W.

    2012-01-01

    Nylon nucleic acids containing oligouridine nucleotides with pendent polyamide linkers and flanked by unmodified heteronucleotide sequences were prepared by DNA templated synthesis. Templation was more efficient than the single-stranded synthesis: Coupling step yields were as high as 99.2%, with up to 7 amide linkages formed in the synthesis of a molecule containing 8 modified nucleotides. Controlled digestion by calf spleen phosphodiesterase enabled the mapping of modified nucleotides in the...

  3. Silicotungstic Acid Modified Bentonite: An Efficient Catalyst for Synthesis of Acetal Derivatives of Aldehydes and Ketones

    OpenAIRE

    Reshu Chaudhary; Monika Datta

    2013-01-01

    Acetals and ketals are among the important materials of organic synthesis and as protecting agent of carbonyl functionality. A milder, efficient and green synthesis of acetals and ketals has been developed using Silicotungstic acid modified Bentonite (STA-Ben) as a catalyst. STA-Ben has been synthesized and characterized by various analytical techniques. It has been found to be an efficient and reusable catalyst for the synthesis of acetyl derivatives in excellent yield...

  4. The asymmetric synthesis of beta-haloaryl-beta-amino acid derivatives

    OpenAIRE

    Bull, SD; Davies, SG; Delgado-Ballester, S; Fenton, G; Kelly, PM; Smith, AD

    2000-01-01

    Lithium N-benzyl-N-?-methyl-4-methoxybenzylamide is employed as a homochiral ammonia equivalent for the asymmetric synthesis of ?-haloaryl-?-amino acid derivatives using a conjugate addition/oxidative deprotection strategy.

  5. A Facile and Efficient Synthesis of N-aryl Imides Using Trifluoroacetic Acid

    Directory of Open Access Journals (Sweden)

    Sunita B. Shinde

    2011-04-01

    Full Text Available An efficient protocol has been demonstrated for the synthesis of pthalimides, maleimides and succinimides in excellent yield using trifluoroacetic acid as the reaction medium and promoter.

  6. An improved synthesis for the (Z)-14-methyl-9-pentadecenoic acid and its topoisomerase I inhibitory activity

    OpenAIRE

    Néstor M. Carballeira; Sanabria, David; Oyola, Delise

    2007-01-01

    An improved synthesis for the (Z)-14-methyl-9-pentadecenoic acid was developed based on the appropriate use of (trimethylsilyl)acetylene as the key reagent in the synthesis. The reported synthesis started with commercially available 8-bromo-1-octanol and furnished the desired acid in seven steps and in a 16% overall yield, a significant improvement over the previous ...

  7. Regulation of bile acid synthesis in man. Presence of a diurnal rhythm.

    OpenAIRE

    Duane, W C; Levitt, D G; Mueller, S M; Behrens, J C

    1983-01-01

    Regulation of bile acid synthesis in man is incompletely understood, in part because of difficulty in making measurements over short time periods when the enterohepatic circulation is intact. We investigated the possibility of a diurnal rhythm of bile acid synthesis in three human subjects given [26-14C]cholesterol. When this isotope of cholesterol, which is randomly labeled in the 26 and 27 positions, is converted to bile acid, the 14C is released as propionic acid randomly labeled in the 1 ...

  8. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    Directory of Open Access Journals (Sweden)

    Xuezheng Liang

    2010-08-01

    Full Text Available The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and ?-keto esters make this novel carbon based acid one of the best choices for the reaction.

  9. 76 FR 8770 - Polyethylene Terephthalate (Pet) Film From Korea

    Science.gov (United States)

    2011-02-15

    ...COMMISSION [Investigation No. 731-TA-459 (Third Review)] Polyethylene Terephthalate (Pet) Film From Korea AGENCY: United States...five-year review concerning the antidumping duty order on polyethylene terephthalate (PET) film from...

  10. Role of Malic Enzyme during Fatty Acid Synthesis in the Oleaginous Fungus Mortierella alpina

    OpenAIRE

    Hao, Guangfei; Chen, Haiqin; Wang, Lei; Gu, Zhennan; Song, Yuanda; ZHANG, HAO; Chen, Wei; Chen, Yong Q

    2014-01-01

    The generation of NADPH by malic enzyme (ME) was postulated to be a rate-limiting step during fatty acid synthesis in oleaginous fungi, based primarily on the results from research focusing on ME in Mucor circinelloides. This hypothesis is challenged by a recent study showing that leucine metabolism, rather than ME, is critical for fatty acid synthesis in M. circinelloides. To clarify this, the gene encoding ME isoform E from Mortierella alpina was homologously expressed. ME overexpression in...

  11. In vitro synthesis of repressible yeast acid phosphatase: identification of multiple mRNAs and products.

    OpenAIRE

    Bostian, K. A.; Lemire, J. M.; Cannon, L E; Halvorson, H. O.

    1980-01-01

    Antibodies to repressible nonspecific acid phosphatase [APase; orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2] purified from Saccharomyces cerevisiae were used to detect the in vitro products of APase mRNA. Immunoprecipitation of cell-free synthesized protein and of in vivo enzyme from cell extracts has shown that derepression of enzyme synthesis in situ is the result of de novo appearance of functional mRNA followed by de novo protein synthesis. At least three unique A...

  12. Mitochondrial fatty acid synthesis is required for normal mitochondrial morphology and function in Trypanosoma brucei

    OpenAIRE

    Guler, Jennifer L.; Kriegova, Eva; SMITH, TERRY K.; Lukeš, Julius; Englund, Paul T

    2008-01-01

    Trypanosoma brucei use microsomal elongases for de novo synthesis of most of its fatty acids. In addition, this parasite utilizes an essential mitochondrial type II synthase for production of octanoate (a lipoic acid precursor) as well as longer fatty acids such as palmitate. Evidence from other organisms suggests that mitochondrially synthesized fatty acids are required for efficient respiration but the exact relationship remains unclear. In procyclic form trypanosomes, we also found that RN...

  13. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    OpenAIRE

    Hartati Hartati; Mardi Santoso; Sugeng Triwahyono; Didik Prasetyoko

    2013-01-01

    This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous aci...

  14. Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng, E-mail: zhxch@zzu.edu.cn

    2014-03-15

    MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H{sub 2}O{sub 2} indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions. Highlights: • 5–45 wt% HPW/MCM-48 mesoporous catalysts were prepared and characterized. • Their catalytic activities for the green synthesis of benzoic acid were investigated. • HPW/MCM-48 was approved to be an efficient catalyst. • 5 wt% HPW/MCM-48 exhibited the highest catalytic activity.

  15. Total synthesis and structure elucidation of JBIR-39: a linear hexapeptide possessing piperazic acid and ?-hydroxypiperazic acid residues.

    Science.gov (United States)

    Yoshida, Masahito; Sekioka, Naoki; Izumikawa, Miho; Kozone, Ikuko; Takagi, Motoki; Shin-Ya, Kazuo; Doi, Takayuki

    2015-02-01

    The total synthesis and stereochemical structural elucidation of JBIR-39, containing four nonproteinogenic piperazic acid (Piz) residues, is reported. The synthesis includes Sc(OTf)3 -catalyzed acylation of a Piz(?-OTBS) derivative with piperazic acid chloride, providing the desired Piz-Piz(?-OTBS) dipeptide in high yield without epimerization. After assembling two additional Piz moieties and (S)-isoleucic acid at the N-terminus, amidation with the (R)-?-methylserine ester at the C-terminus, and deprotection afforded the desired (2R,8S)-hexapeptide, which is the assumed structure of JBIR-39. Although the spectral data of the (2R,8S)-hexapeptide was not identical to JBIR-39, further synthesis of three stereoisomers confirmed the stereochemical structure of JBIR-39 to be (2S,6S,8S,11R,16S,21R,26S,27S). PMID:25524716

  16. Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

    International Nuclear Information System (INIS)

    MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H2O2 indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions. Highlights: • 5–45 wt% HPW/MCM-48 mesoporous catalysts were prepared and characterized. • Their catalytic activities for the green synthesis of benzoic acid were investigated. • HPW/MCM-48 was approved to be an efficient catalyst. • 5 wt% HPW/MCM-48 exhibited the highest catalytic activity

  17. Chemical recycling of post-consumer PET: structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature; Reciclagem quimica do PET pos-consumo: caracterizacao estrutural do acido tereftalico e efeito da hidrolise alcalina em baixa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Talitha Granja; Almeida, Yeda Medeiros Bastos de; Vinhas, Gloria Maria, E-mail: gmvinhas@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Quimica

    2014-09-15

    Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L{sup -1} NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed. (author)

  18. Synthesis of functionalized fluorescent gold nanoclusters for acid phosphatase sensing

    Science.gov (United States)

    Sun, Jian; Yang, Fan; Yang, Xiurong

    2015-10-01

    A novel and convenient one-pot but two-step synthesis of fluorescent gold nanoclusters, incorporating glutathione (GSH) and 11-mercaptoundecanoic acid (MUA) as the functionalized ligands (i.e. AuNCs@GSH/MUA), is demonstrated. Herein, the mixing of HAuCl4 and GSH in aqueous solution results in the immediate formation of non-fluorescent GSH-Au+ complexes, and then a class of ~2.6 nm GSH-coated AuNCs (AuNCs@GSH) with mild orange-yellow fluorescence after several days. Interestingly, the intense orange-red emitting ~1.7 nm AuNCs@GSH/MUA can be synthesized within seconds by introducing an alkaline aqueous solution of MUA into the GSH-Au+ complexes or AuNC@GSH solution. Subsequently, a reliable AuNC@GSH/MUA-based real-time assay of acid phosphatase (ACP) is established for the first time, inspired by the selective coordination of Fe3+ with surface ligands of AuNCs, the higher binding affinity between the pyrophosphate ion (PPi) and Fe3+, and the hydrolysis of PPi into orthophosphate by ACP. Our fluorescent chemosensor can also be applied to assay ACP in a real biological sample and, furthermore, to screen the inhibitor of ACP. This report paves a new avenue for synthesizing AuNCs based on either the bottom-up reduction or top-down etching method, establishing real-time fluorescence assays for ACP by means of PPi as the substrate, and further exploring the sensing applications of fluorescent AuNCs.A novel and convenient one-pot but two-step synthesis of fluorescent gold nanoclusters, incorporating glutathione (GSH) and 11-mercaptoundecanoic acid (MUA) as the functionalized ligands (i.e. AuNCs@GSH/MUA), is demonstrated. Herein, the mixing of HAuCl4 and GSH in aqueous solution results in the immediate formation of non-fluorescent GSH-Au+ complexes, and then a class of ~2.6 nm GSH-coated AuNCs (AuNCs@GSH) with mild orange-yellow fluorescence after several days. Interestingly, the intense orange-red emitting ~1.7 nm AuNCs@GSH/MUA can be synthesized within seconds by introducing an alkaline aqueous solution of MUA into the GSH-Au+ complexes or AuNC@GSH solution. Subsequently, a reliable AuNC@GSH/MUA-based real-time assay of acid phosphatase (ACP) is established for the first time, inspired by the selective coordination of Fe3+ with surface ligands of AuNCs, the higher binding affinity between the pyrophosphate ion (PPi) and Fe3+, and the hydrolysis of PPi into orthophosphate by ACP. Our fluorescent chemosensor can also be applied to assay ACP in a real biological sample and, furthermore, to screen the inhibitor of ACP. This report paves a new avenue for synthesizing AuNCs based on either the bottom-up reduction or top-down etching method, establishing real-time fluorescence assays for ACP by means of PPi as the substrate, and further exploring the sensing applications of fluorescent AuNCs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04826e

  19. Synthesis and Characterization of Fatty Acid/Amino Acid Self-Assemblies

    Directory of Open Access Journals (Sweden)

    Joanna Gajowy

    2014-10-01

    Full Text Available In this paper, we discuss the synthesis and self-assembling behavior of new copolymers derived from fatty acid/amino acid components, namely dimers of linoleic acid (DLA and tyrosine derived diphenols containing alkyl ester pendent chains, designated as “R” (DTR. Specific pendent chains were ethyl (E and hexyl (H. These poly(aliphatic/aromatic-ester-amides were further reacted with poly(ethylene glycol (PEG and poly(ethylene glycol methyl ether of different molecular masses, thus resulting in ABA type (hydrophilic-hydrophobic-hydrophilic triblock copolymers. We used Fourier transform infrared (FTIR and nuclear magnetic resonance (NMR spectroscopies to evaluate the chemical structure of the final materials. The molecular masses were estimated by gel permeation chromatography (GPC measurements. The self-organization of these new polymeric systems into micellar/nanospheric structures in aqueous environment was evaluated using ultraviolet/visible (UV-VIS spectroscopy, dynamic light scattering (DLS and transmission electron microscopy (TEM. The polymers were found to spontaneously self-assemble into nanoparticles with sizes in the range 196–239 nm and critical micelle concentration (CMC of 0.125–0.250 mg/mL. The results are quite promising and these materials are capable of self-organizing into well-defined micelles/nanospheres encapsulating bioactive molecules, e.g., vitamins or antibacterial peptides for antibacterial coatings on medical devices.

  20. Synthesis of carboranyl amino acids, hydantoins, and barbiturates

    International Nuclear Information System (INIS)

    The syntheses of three novel boronated hydantoins, 5-(o-carboran-1-ylmethyl)hydantoin, 14, the tetraphenylphosphonium salt of 7-(hydantoin-5-ylmethyl)dodecahydro-7,8-dicarba-nido-undecaborate, 15, 5-(o-carboran-1-ylmethyl)-2-thiohydantoin, 16, and two new barbiturates, 5,5-bis(but-2-ynyl)barbiturate, 18, and 5,5-bis[(2-methyl-0-carboran-1-yl)methyl]barbiturate, 20, are described. Hydantoins 14-16 were synthesized from o-carboranylalanine (Car, 13). The detailed synthesis of Car and two other carborane-containing amino acids, O-(o-carboran-1-ylmethyl)tyrosine (CBT, 5a) and p-(o-carboran-1-yl)phenylalanine (CBPA, 5b), presented earlier as a communication, 16 are also described. Hydantoin 14 and barbiturates 18 and 20 were tested for their potential anticonvulsant activity. Initial qualitative screening showed moderate activities for hydantoin 14 and barbiturate 18. Barbiturate 20 had no activity. Compound 14 appeared to be nontoxic at doses of 300 mg/kg (mice, ip) and 50 mg/kg (rats, oral). However, 18 was very toxic under similar conditions

  1. A thermodynamic basis for prebiotic amino acid synthesis and the nature of the first genetic code

    CERN Document Server

    Higgs, Paul G

    2009-01-01

    Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these ten early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.

  2. Suppression of glycosaminoglycan synthesis by articular cartilage, but not of hyaluronic acid synthesis by synovium, after exposure to radiation

    International Nuclear Information System (INIS)

    We recently found that injection of 2 mCi of yttrium 90 (90Y; approximately 23,000 rads) into normal canine knees stimulated glycosaminoglycan (GAG) synthesis by femoral condylar cartilage. The present investigation was conducted to determine whether radiation affects cartilage metabolism directly. Rates of GAG synthesis and degradation in normal canine articular cartilage were studied following irradiation. Cultured synovium from the same knees was treated similarly, to determine the effects of irradiation on hyaluronic acid synthesis. Twenty-four hours after exposure to 1,000 rads, 10,000 rads, or 50,000 rads, 35S-GAG synthesis by the cartilage was 93%, 69%, and 37%, respectively, of that in control, nonirradiated cartilage. The effect was not rapidly reversible: 120 hours after exposure to 50,000 rads, GAG synthesis remained at only 28% of the control level. Autoradiography showed marked suppression of 35S uptake by chondrocytes after irradiation. Cartilage GAG degradation was also increased following irradiation: 4 hours and 8 hours after exposure to 50,000 rads, the cartilage GAG concentration was only 66% and 54%, respectively, of that at time 0, while corresponding values for control, nonirradiated cartilage were 90% and 87%. In contrast to its effects on cartilage GAG metabolism, radiation at these levels had no effect on synovial hyaluronic acid synthesis

  3. Crystal structure of Spot 14, a modulator of fatty acid synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Colbert, Christopher L.; Kim, Chai-Wan; Moon, Young-Ah; Henry, Lisa; Palnitkar, Maya; McKean, William B.; Fitzgerald, Kevin; Deisenhofer, Johann; Horton, Jay D.; Kwon, Hyock Joo (Alnylam Pharm.); (UTSMC)

    2011-09-06

    Spot 14 (S14) is a protein that is abundantly expressed in lipogenic tissues and is regulated in a manner similar to other enzymes involved in fatty acid synthesis. Deletion of S14 in mice decreased lipid synthesis in lactating mammary tissue, but the mechanism of S14's action is unknown. Here we present the crystal structure of S14 to 2.65 {angstrom} and biochemical data showing that S14 can form heterodimers with MIG12. MIG12 modulates fatty acid synthesis by inducing the polymerization and activity of acetyl-CoA carboxylase, the first committed enzymatic reaction in the fatty acid synthesis pathway. Coexpression of S14 and MIG12 leads to heterodimers and reduced acetyl-CoA carboxylase polymerization and activity. The structure of S14 suggests a mechanism whereby heterodimer formation with MIG12 attenuates the ability of MIG12 to activate ACC.

  4. Transesterification of Dimethyl Terephthalate with Ethylene Glycol

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jinhong; Cho, Impyo; Jo, Sanhwan; Cho, Minjung; Han, Myungwan [Chungnam National University, Daejeon (Korea, Republic of); Kang, Kyungsuk [Siontech, Daejeon (Korea, Republic of)

    2013-02-15

    The kinetics of the transesterification of dimethyl terephthalate (DMT) with ethylene glycol (EG) was studied in a batch reactor. Bishydroxyethyl terephthalate (BHET), which is poly(ethylene terephthalate) (PET) monomer, can be produced by the transesterification reaction. Zinc acetate was used as a catalyst. Previous kinetic studies was carried out in a semi-batch reactor where generated methanol was removed so that reverse reactions were not considered in the kinetic expressions, resulting in inaccuracy of the kinetic model. Mathematical models of a batch reactor for the tranesterification reaction were developed and used to characterize the reaction kinetics and the composition distribution of the reaction products. More accurate models than previous ones were obtained and found to have a good agreement between model predictions and experimental data. Effect of process variables on the esterification reaction was investigated based on the experimental and simulation results.

  5. Transesterification of Dimethyl Terephthalate with Ethylene Glycol

    International Nuclear Information System (INIS)

    The kinetics of the transesterification of dimethyl terephthalate (DMT) with ethylene glycol (EG) was studied in a batch reactor. Bishydroxyethyl terephthalate (BHET), which is poly(ethylene terephthalate) (PET) monomer, can be produced by the transesterification reaction. Zinc acetate was used as a catalyst. Previous kinetic studies was carried out in a semi-batch reactor where generated methanol was removed so that reverse reactions were not considered in the kinetic expressions, resulting in inaccuracy of the kinetic model. Mathematical models of a batch reactor for the tranesterification reaction were developed and used to characterize the reaction kinetics and the composition distribution of the reaction products. More accurate models than previous ones were obtained and found to have a good agreement between model predictions and experimental data. Effect of process variables on the esterification reaction was investigated based on the experimental and simulation results

  6. Synthesis of deuterium-labelled methylphenidate, p-hydroxy-methylphenidate, ritalinic acid and p-hydroxyritalinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, K.; Kilts, C.; Breese, G. (North Carolina Univ., Chapel Hill (USA). School of Medicine)

    1982-04-01

    The synthesis of threo-dl-methylphenidate (Ritalin 1), threo-dl-p-hydroxy-methylphenidate (3), threo-dl-ritalinic acid (2), and threo-dl-p-hydroxyritalinic acid (4) with deuterium incorporated in the piperidine ring is described. These compounds were synthesized for use as internal standards for mass fragmentographic assays of methylphenidate and its metabolites. The synthetic scheme described resulted in less than 0.05% /sup 2/H/sub 0/ in the piperidine ring in any of the preparations.

  7. Synthesis of Long Chain Unsaturated-alpha,omega-Dicarboxylic Acids from Renewable Materials via Olefin Metathesis

    Science.gov (United States)

    The self-metathesis reaction of soy, rapeseed, tall, and linseed oil fatty acids was investigated for the synthesis of symmetrical long-chain unsaturated-alpha,omega-dicarboxylic acids. The metathesis reactions were carried out in the presence of a Grubbs catalyst under solvent-free conditions at a...

  8. Synthesis and application of stereospecifically tritium or deuterium labelled mevalonic acid

    International Nuclear Information System (INIS)

    Together with a general introduction into the problem of prochirality, a survey is given of the possibilities of both chemical and enzymatic synthesis of stereospecifically deuterium or tritium labelled mevalonic acid. Furthermore, essential works on the application of these labelled mevalonic acids are discussed. (author)

  9. 4-Dimenthylaminopyridine or Acid-Catalyzed Synthesis of Esters: A Comparison

    Science.gov (United States)

    van den Berg, Annemieke W. C.; Hanefeld, Ulf

    2006-01-01

    A set of highly atom-economic experiments was developed to highlight the differences between acid- and base-catalyzed ester syntheses and to introduce the principles of atom economy. The hydrochloric acid-catalyzed formation of an ester was compared with the 4-dimethylaminopyradine-catalyzed ester synthesis.

  10. A Three Step Synthesis of 11-Cycloheptylundecanoic Acid, a Component of the Thermoacidophile Alicyclobacillus cycloheptanicus

    OpenAIRE

    Vasant R. Mamdapur; Sham A. Hassarajani

    1998-01-01

    A simple synthesis of the methyl ester of 11-cycloheptylundecanoic acid (1), isolated from the lipid fraction of the thermoacidofile, Alicyclobacillus cycloheptanicus has been developed. This involved regioselective Grignard coupling between cycloheptylmagnesium bromide and methyl 11-bromoundecanoate (2), prepared from 10- undecanoic acid.

  11. Toward the Synthesis of Cobyric Acid. Enantioselective Syntheses of Completely Differentiated Ring D Synthons

    OpenAIRE

    Wang, Hui; Tassa, Carlos; Jacobi, Peter A.

    2008-01-01

    Alkyne acids 11 were prepared in an enantioselective fashion from allylic ester derivatives 18 or 20 by Ireland-Claisen rearrangement, followed by Si-assisted elimination of HBr. The title compounds are attractive ring D synthons for an ongoing synthesis of cobyric acid.

  12. INFLUENCE OF THE SYNTHESIS PARAMETERS ON SOME TEXTURAL PROPERTIES OF ROMANIAN ACID ACTIVATED BENTONITE

    OpenAIRE

    URSU ALINA VIOLETA; JINESCU GHEORGHITA; NISTOR ILEANA DENISA; GEORGESCU ANA MARIA; MUNTIANU GHIMICIU GABRIELA; SILION MIHAELA

    2010-01-01

    This paper presents the influence of synthesis parameters (concentration of acid solution and the solid: liquid ratio) on textural characteristics of bentonite activated clays: nitrogen adsorption/desorption isotherms, surface and pore size distribution. Acid activated clays present higher specific surface area than the natural bentonite used as feed stock and a better adsorption capacity.

  13. INFLUENCE OF THE SYNTHESIS PARAMETERS ON SOME TEXTURAL PROPERTIES OF ROMANIAN ACID ACTIVATED BENTONITE

    Directory of Open Access Journals (Sweden)

    URSU ALINA VIOLETA

    2010-08-01

    Full Text Available This paper presents the influence of synthesis parameters (concentration of acid solution and the solid: liquid ratio on textural characteristics of bentonite activated clays: nitrogen adsorption/desorption isotherms, surface and pore size distribution. Acid activated clays present higher specific surface area than the natural bentonite used as feed stock and a better adsorption capacity.

  14. 78 FR 9363 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Notice of...

    Science.gov (United States)

    2013-02-08

    ...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...2\\ See Polyethylene Terephthalate Film, Sheet, and Strip...reconsider the SV for polyethylene terephthalate (``PET'')...

  15. Selective inhibition of leukotriene C4 synthesis in human neutrophils by ethacrynic acid

    International Nuclear Information System (INIS)

    Addition of glutathione S-transferase inhibitors, ethyacrynic acid (ET), caffeic acid (CA), and ferulic acid (FA) to human neutrophils led to inhibition of leukotriene C4 (LTC4) synthesis induced by calcium ionophore A23187. ET is the most specific of these inhibitors for it had little effect on LTB4, PGE2, and 5-HETE synthesis. The inhibition of LTC4 was irreversible and time dependent. ET also had little effect on 3H-AA release from A23187-stimulated neutrophils

  16. Radiotracer studies on the synthesis of prorennin and rennin using 14C-amino acids

    International Nuclear Information System (INIS)

    In vivo incorporation of 14C-amino acids into the prorennin and rennin fractions of the abomasal tissue of the intact animal (i.e. calf) has been investigated by : (1) intravenous injection of the label and subsequent isolation of rennin and prorennin fractions from the excised abomasum and (2) feeding. of milk whey fortified with the label to a fistulated kid and subsequent processing of the abomasal juice for rennet extraction. Prorennin incorporates more radioactivity than rennin. This indicates that abomasal tissue uses blood amino acids for prorennin synthesis, but amino acids fed through dietary channels may not be used for rennin synthesis. (M.G.B.)

  17. Synthesis of new indolecarboxylic acids related to the plant hormone indoleacetic acid IAA

    Scientific Electronic Library Online (English)

    Flávia A. F. da, Rosa; Ricardo A., Rebelo; Maria G., Nascimento.

    2003-01-01

    Full Text Available A síntese dos ácidos 5,6-metilenodioxi-indol-3-il-metanóico 8 e 5,6-metilenodioxi-indol-3-il-acético 13 é descrita. Piperonal foi empregado como material de partida, sendo a construção do heterociclo altamente regioespecífica e está fundamentada na reação de Hemetsberger do correspondente beta-azido [...] estireno. O composto 8 foi obtido como intermediário pivotal na preparação de 13, tendo-se conduzida a reação de Mannich para a introdução da cadeia lateral alquílica. A rota sintética empregada englobou oito etapas e conduziu a formação de 13 com rendimento total de 26%. A formação do heterociclo indólico via ciclização redutiva de o,beta-dinitroestireno é também apresentada. Abstract in english The synthesis of 5,6-methylenedioxy-indol-3-yl-methanoic acid 8 and 5,6-methylenedioxy-indol-3-yl-acetic acid 13 is described. Piperonal was employed as starting material, and the construction of the heterocyclic ring based on the Hemetsberger reaction of the corresponding beta-azidostyrene was high [...] ly regiospecific. Compound 8 was obtained as a key intermediate towards 13, and a Mannich reaction was used to introduce the required alkyl side chain. The route comprised eight steps giving 13 in 26% overall yield. The formation of the indolic ring via reductive cyclisation of o,beta-dinitrostyrene is also presented.

  18. Decreased hepatotoxic bile acid composition and altered synthesis in progressive human nonalcoholic fatty liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Lake, April D. [University of Arizona, Department of Pharmacology and Toxicology, Tucson, AZ 85721 (United States); Novak, Petr [Biology Centre ASCR, Institute of Plant Molecular Biology, Ceske Budejovice 37001 (Czech Republic); Shipkova, Petia; Aranibar, Nelly; Robertson, Donald; Reily, Michael D. [Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Co., Princeton, NJ 08543 (United States); Lu, Zhenqiang [The Arizona Statistical Consulting Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Lehman-McKeeman, Lois D. [Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Co., Princeton, NJ 08543 (United States); Cherrington, Nathan J., E-mail: cherrington@pharmacy.arizona.edu [University of Arizona, Department of Pharmacology and Toxicology, Tucson, AZ 85721 (United States)

    2013-04-15

    Bile acids (BAs) have many physiological roles and exhibit both toxic and protective influences within the liver. Alterations in the BA profile may be the result of disease induced liver injury. Nonalcoholic fatty liver disease (NAFLD) is a prevalent form of chronic liver disease characterized by the pathophysiological progression from simple steatosis to nonalcoholic steatohepatitis (NASH). The hypothesis of this study is that the ‘classical’ (neutral) and ‘alternative’ (acidic) BA synthesis pathways are altered together with hepatic BA composition during progression of human NAFLD. This study employed the use of transcriptomic and metabolomic assays to study the hepatic toxicologic BA profile in progressive human NAFLD. Individual human liver samples diagnosed as normal, steatosis, and NASH were utilized in the assays. The transcriptomic analysis of 70 BA genes revealed an enrichment of downregulated BA metabolism and transcription factor/receptor genes in livers diagnosed as NASH. Increased mRNA expression of BAAT and CYP7B1 was observed in contrast to decreased CYP8B1 expression in NASH samples. The BA metabolomic profile of NASH livers exhibited an increase in taurine together with elevated levels of conjugated BA species, taurocholic acid (TCA) and taurodeoxycholic acid (TDCA). Conversely, cholic acid (CA) and glycodeoxycholic acid (GDCA) were decreased in NASH liver. These findings reveal a potential shift toward the alternative pathway of BA synthesis during NASH, mediated by increased mRNA and protein expression of CYP7B1. Overall, the transcriptomic changes of BA synthesis pathway enzymes together with altered hepatic BA composition signify an attempt by the liver to reduce hepatotoxicity during disease progression to NASH. - Highlights: ? Altered hepatic bile acid composition is observed in progressive NAFLD. ? Bile acid synthesis enzymes are transcriptionally altered in NASH livers. ? Increased levels of taurine and conjugated bile acids are observed in NASH. ? Hepatic bile acid synthesis shifts toward the alternative pathway in NASH.

  19. Direct microwave-assisted amino acid synthesis by reaction of succinic acid and ammonia in the presence of magnetite

    Science.gov (United States)

    Jiang, Nan; Liu, Dandan; Shi, Weiguang; Hua, Yingjie; Wang, Chongtai; Liu, Xiaoyang

    2013-10-01

    Since the discovery of submarine hot vents in the late 1970s, it has been postulated that submarine hydrothermal environments would be suitable for emergence of life on Earth. To simulate warm spring conditions, we designed a series of microwave-assisted amino acid synthesis involving direct reactions between succinic acid and ammonia in the presence of the magnetite catalyst. These reactions which generated aspartic acid and glycine were carried out under mild temperatures and pressures (90-180 °C, 4-19 bar). We studied this specific reaction inasmuch as succinic acid and ammonia were traditionally identified as prebiotic compounds in primitive deep-sea hydrothermal systems on Earth. The experimental results were discussed in both biochemical and geochemical context to offer a possible route for abiotic amino acid synthesis. With extremely diluted starting materials (0.002 M carboxylic acid and 0.002 M ammonia) and catalyst loading, an obvious temperature dependency was observed in both cases [neither product was detected at 90 °C in comparison with 21.08 ?mol L-1 (aspartic acid) and 70.25 umol L-1 (glycine) in 180 °C]. However, an opposite trend presented for reaction time factor, namely a positive correlation for glycine, but a negative one for aspartic acid.

  20. Effects of unsaturated fatty acid deprivation on neutral lipid synthesis in Saccharomyces cerevisiae.

    OpenAIRE

    Buttke, T M; Pyle, A L

    1982-01-01

    The effects of unsaturated fatty acid deprivation on lipid synthesis in Saccharomyces cerevisiae strain GL7 were determined by following the incorporation of [14C]acetate. Compared to yeast cells grown with oleic acid, unsaturated fatty acid-deprived cells contained 200 times as much 14C label in squalene, with correspondingly less label in 2,3-oxidosqualene and 2,3;22,23-dioxidosqualene. Cells deprived of either methionine or cholesterol did not accumulate squalene, demonstrating that the ef...

  1. Duodenal prostaglandin synthesis and acid load in health and in duodenal ulcer disease

    International Nuclear Information System (INIS)

    We sought to test the hypothesis that duodenal ulcer disease results from an imbalance between duodenal acid load, an injurious force, and mucosal prostaglandin generation, a protective factor. Ten patients with duodenal ulcer and 8 healthy controls were studied. The duodenal acid load after an amino acid soup was quantified by a double-marker technique. Mucosal biopsy specimens were taken endoscopically from the duodenal bulb before and after the test meal. Prostaglandin synthesis activity was measured by incubating biopsy homogenates in excess [14C]arachidonic acid. Although mean duodenal acid load was higher in duodenal ulcer, ranges overlapped. Neither the qualitative nor quantitative profile of mucosal prostaglandin synthesis activities differed significantly between test groups. Prostaglandin synthesis activities, however, tended to increase post cibum in controls, but change little or decrease in duodenal ulcer. Only by comparing the responses with a meal of both parameters together (duodenal acid load and the change in prostaglandin synthesis activities) was there complete or nearly complete separation of duodenal ulcer from controls. Greatest discrimination was observed with prostacyclin (6-keto-PGF1 alpha). We conclude that in health, mucosal prostaglandin generation in the duodenum is induced post cibum in relation to duodenal acid load; this may be a physiologic example of adaptive cytoprotection. In duodenal ulcer there may be a defect in such a mechanism

  2. Poly(ethylene terephthalate-co-isophthalate) copolyesters obtained from ethylene terephthalate and isophthalate oligomers

    OpenAIRE

    Ubach, Joan; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Quintana Vicente, Robert; Alla Bedahnane, Abdelilah; Muñoz Guerra, Sebastián; Rudé, Elisabet

    2010-01-01

    A series of poly(ethylene terephthalate-co-isophthalate) copolyesters containing up to 50%-mole of isophthalic units were prepared by polycondensation from ethylene terephthalate and ethylene isophthalate fractions of linear oligomers containing from 5 to 6 repeating units in average. The polyesters were obtained in good yields and with high molecular weights. The microstructure of the copolyesters was studied as a function of reaction time by 13C-NMR showing that a random dist...

  3. Synthesis and Hydrolytic Degradation of Substituted Poly(DL-Lactic Acid)s

    OpenAIRE

    Hideto Tsuji; Takehiko Eto; Yuzuru Sakamoto

    2011-01-01

    Non-substituted racemic poly(DL-lactic acid) (PLA) and substituted racemic poly(DL-lactic acid)s or poly(DL-2-hydroxyalkanoic acid)s with different side-chain lengths, i.e., poly(DL-2-hydroxybutanoic acid) (PBA), poly(DL-2-hydroxyhexanoic acid) (PHA), and poly(DL-2-hydroxydecanoic acid) (PDA) were synthesized by acid-catalyzed polycondensation of DL-lactic acid (LA), DL-2-hydroxybutanoic acid (BA), DL-2-hydroxyhexanoic acid (HA), and DL-2-hydroxydecanoic acid (DA), respectively. The hydrolyti...

  4. RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified ?-linolenic acid by rat liver

    OpenAIRE

    Gao, Fei; Taha, Ameer Y.; Ma, Kaizong; Chang, Lisa; Kiesewetter, Dale; Rapoport, Stanley I

    2012-01-01

    Docosahexaenoic acid (DHA, 22:6n-3), an n-3 polyunsaturated fatty acid (PUFA) found at high concentrations in brain and retina and critical to their function, can be obtained from fish products or be synthesized from circulating ?-linolenic acid (?-LNA, 18:3n-3) mainly in the liver. With aging, liver synthetic enzymes are reported reduced or unchanged in the rat. To test whether liver synthesis-secretion of DHA from ?-LNA changes with age, we measured whole-body DHA conversion coefficients an...

  5. Synthesis of Triamino Acid Building Blocks with Different Lipophilicities

    OpenAIRE

    Maity, Jyotirmoy; Honcharenko, Dmytro; Strömberg, Roger

    2015-01-01

    To obtain different amino acids with varying lipophilicity and that can carry up to three positive charges we have developed a number of new triamino acid building blocks. One set of building blocks was achieved by aminoethyl extension, via reductive amination, of the side chain of ortnithine, diaminopropanoic and diaminobutanoic acid. A second set of triamino acids with the aminoethyl extension having hydrocarbon side chains was synthesized from diaminobutanoic acid. The aldehydes needed for...

  6. Solvent-free lipase-catalyzed synthesis of a novel hydroxyl-fatty acid derivative of kojic acid.

    Science.gov (United States)

    El-Boulifi, Noureddin; Ashari, Siti Efliza; Serrano, Marta; Aracil, Jose; Martínez, Mercedes

    2014-02-01

    The aim of this work was the synthesis of a novel hydroxyl-fatty acid derivative of kojic acid rich in kojic acid monoricinoleate (KMR) which can be widely used in the cosmetic and food industry. The synthesis of KMR was carried out by lipase-catalysed esterification of ricinoleic and kojic acids in solvent-free system. Three immobilized lipases were tested and the best KMR yields were attained with Lipozyme TL IM and Novozym 435. Since Lipozyme TL IM is the cheapest, it was selected to optimize the reaction conditions. The optimal reaction conditions were 80 °C for the temperature, 1:1 for the alcohol/acid molar ratio, 600 rpm for stirring speed and 7.8% for the catalyst concentration. Under these conditions, the reaction was scaled up in a 5×10?³ m³ stirred tank reactor. ¹H-¹³C HMBC-NMR showed that the primary hydroxyl group of kojic acid was regioselectively esterified. The KMR has more lipophilicity than kojic acid and showed antioxidant activity that improves the oxidation stability of biodiesel. PMID:24411455

  7. Synthesis and biological properties of amino acids and peptides containing a tetrazolyl moiety

    Science.gov (United States)

    Popova, E. A.; Trifonov, R. E.

    2015-09-01

    Literature data published mainly in the last 15 years on the synthesis and biological properties of amino acid analogues and derivatives containing tetrazolyl moieties are analyzed. Tetrazolyl analogues and derivatives of amino acids and peptides are shown to be promising for medicinal chemistry. Being polynitrogen heterocyclic systems comprising four endocyclic nitrogen atoms, tetrazoles can behave as acids and bases and form strong hydrogen bonds with proton donors (more rarely, with acceptors). They have high metabolic stability and are able to penetrate biological membranes. The review also considers the synthesis and properties of linear and cyclic peptides based on modified amino acids incorporating a tetrazolyl moiety. A special issue is the discussion of the biological properties of tetrazole-containing amino acids and peptides, which exhibit high biological activity and can be used to design new drugs. The bibliography includes 200 references.

  8. Synthesis and role of salicylic acid in wheat varieties with different levels of cadmium tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, Viktória; Gondor, Orsolya K.; Szalai, Gabriella; Darkó, Éva; Majláth, Imre; Janda, Tibor; Pál, Magda, E-mail: pal.magda@agrar.mta.hu

    2014-09-15

    Highlights: • Cd induces the salicylic acid metabolism in wheat. • Salicylic acid is synthesized via benzoic acid and/or ortho-hydroxy-cinnamic acid. • Cd tolerance can be explained by the highly induced glutathione metabolism. • Salicylic acid signalling is correlated with glutathione-related mechanisms. - Abstract: Wheat genotypes with different endogenous SA contents were investigated, in order to reveal how cadmium influences salicylic acid (SA) synthesis, and to find possible relationships between SA and certain protective compounds (members of the antioxidants and the heavy metal detoxification system) and between the SA content and the level of cadmium tolerance. Cadmium exposure induced SA synthesis, especially in the leaves, and it is suggested that the phenyl-propanoid synthesis pathway is responsible for the accumulation of SA observed after cadmium stress. Cadmium influenced the synthesis and activation of protective compounds to varying extents in wheat genotypes with different levels of tolerance; the roots and leaves also responded differently to cadmium stress. Although a direct relationship was not found between the initial SA levels and the degree of cadmium tolerance, the results suggest that the increase in the root SA level during cadmium stress in the Mv varieties could be related with the enhancement of the internal glutathione cycle, thus inducing the antioxidant and metal detoxification systems, which promote Cd stress tolerance in wheat seedlings. The positive correlation between certain SA-related compounds and protective compounds suggests that SA-related signalling may also play a role in the acclimation to heavy metal stress.

  9. Synthesis and role of salicylic acid in wheat varieties with different levels of cadmium tolerance

    International Nuclear Information System (INIS)

    Highlights: • Cd induces the salicylic acid metabolism in wheat. • Salicylic acid is synthesized via benzoic acid and/or ortho-hydroxy-cinnamic acid. • Cd tolerance can be explained by the highly induced glutathione metabolism. • Salicylic acid signalling is correlated with glutathione-related mechanisms. - Abstract: Wheat genotypes with different endogenous SA contents were investigated, in order to reveal how cadmium influences salicylic acid (SA) synthesis, and to find possible relationships between SA and certain protective compounds (members of the antioxidants and the heavy metal detoxification system) and between the SA content and the level of cadmium tolerance. Cadmium exposure induced SA synthesis, especially in the leaves, and it is suggested that the phenyl-propanoid synthesis pathway is responsible for the accumulation of SA observed after cadmium stress. Cadmium influenced the synthesis and activation of protective compounds to varying extents in wheat genotypes with different levels of tolerance; the roots and leaves also responded differently to cadmium stress. Although a direct relationship was not found between the initial SA levels and the degree of cadmium tolerance, the results suggest that the increase in the root SA level during cadmium stress in the Mv varieties could be related with the enhancement of the internal glutathione cycle, thus inducing the antioxidant and metal detoxification systems, which promote Cd stress tolerance in wheat seedlings. The positive correlation between certain SA-related compounds and protective compounds suggests that SA-related signalling may also play a role in the acclimation to heavy metal stress

  10. Synthesis and interconversion of the four isomeric 6-oxo-2,4-heptadienoic acids

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, A.L.; Seltzer, S.

    1985-01-01

    The synthesis of the structural isomers of 6-oxo-2,4-heptadienoic acid was undertaken as a means of providing analogues to investigate the structural requirements of maleylacetone cis-trans isomerase. 6-Oxo-2(Z),4(E)-heptadienoic acid and the methyl esters of 6-oxo-2(E),4(Z)-, 6-oxo-2(Z),4(Z)-, and 6-oxo-2(E),4(E)-heptadienoic acid were synthesized. Base-catalyzed hydrolysis of these esters furnished the corresponding acids except in the case of the 2Z,4Z isomer, which yielded instead the 2Z,4E acid. A mechanism for isomerization is suggested. Photocatalyzed isomerization of the acids and esters as a possible way of generating the ZZ acid was studied. The properties of the acids, their interaction with the enzyme, and what this suggests about the interaction of substrate maleylacetone with the enzyme is discussed. 16 references, 1 figure, 2 tables.

  11. The synthesis of phosphoribosylpyrophosphate from glucose decreases during amino acid starvation of human lymphoblasts

    International Nuclear Information System (INIS)

    Rib-5-P and PP-Rib-P may be produced from glucose via the oxidative and nonoxidative pentose phosphate pathway. The autthors attempt to know which of these two pathways provides most of the PP-Rib-P needed for nuceotide synthesis and try to determine the regulation of Rib-5-P synthesis from glucose. The effect of amino acid starvation on the oxidative pentose phosphate pathway was examined by measuring 14CO2 production from (1-14C) glucose

  12. The synthesis of (2R)- and (2S)-[2-3H]-propionic acid

    International Nuclear Information System (INIS)

    A practical synthesis of (2R)- and (2S)-[2-3H]-propionic acid is described. The key steps in the synthesis are the reduction of [formyl-3H]-3-methoxy-4-mesyloxybenzaldehyde with R- or S-Alpine Borane to (7S)- and (7R)-[7-3H]-3-methoxy-4-mesyloxybenzyl alcohol and the use of the vanillyl moiety as a masked carboxyl group. (Author)

  13. Calorie restriction increases fatty acid synthesis and whole body fat oxidation rates

    OpenAIRE

    Bruss, Matthew D; Khambatta, Cyrus F.; Ruby, Maxwell A.; Aggarwal, Ishita; Hellerstein, Marc K

    2009-01-01

    Calorie restriction (CR) increases longevity and retards the development of many chronic diseases, but the underlying metabolic signals are poorly understood. Increased fatty acid (FA) oxidation and reduced FA synthesis have been hypothesized to be important metabolic adaptations to CR. However, at metabolic steady state, FA oxidation must match FA intake plus synthesis; moreover, FA intake is low, not high, during CR. Therefore, it is not clear how FA dynamics are altered during CR. Accordin...

  14. Synthesis of Boron Carbide from Boric Acid and Carbon-Containing Precursors

    OpenAIRE

    Genusova T.N.; Zakharova K.; Mednikova A.; Rumyantsev V.

    2013-01-01

    The paper compares low-temperature techniques for boron carbide synthesis. Boron carbide was syn-thesized via reaction between boric acid and various carbon precursors, e.g. phenol-formaldehyde resin, su-crose, carbon black, and potato starch. Initial compositions and carbon precursor preparation techniques were selected for synthesis. The resulting products were characterized by IR spectrometry, X-ray diffrac-tion (XRD) and scanning electron microscopy. Possible boron carbide yields up to 95...

  15. Regulation of Polyglutamic Acid Synthesis by Glutamate in Bacillus licheniformis and Bacillus subtilis

    OpenAIRE

    Kambourova, Margarita; Tangney, Martin; Priest, Fergus G.

    2001-01-01

    The synthesis of polyglutamic acid (PGA) was repressed by exogenous glutamate in strains of Bacillus licheniformis but not in strains of Bacillus subtilis, indicating a clear difference in the regulation of synthesis of capsular slime in these two species. Although extracellular ?-glutamyltranspeptidase (GGT) activity was always present in PGA-producing cultures of B. licheniformis under various growth conditions, there was no correlation between the quantity of PGA and enzyme activity. Moreo...

  16. Genetics Home Reference: Congenital bile acid synthesis defect type 1

    Science.gov (United States)

    ... cholesterol ; chronic ; cirrhosis ; congenital ; deficiency ; dehydrogenase ; digestion ; digestive ; enzyme ; failure to thrive ; feces ; gene ; inflammation ; inherited ; intestine ; jaundice ; oxidoreductase ; prevalence ; recessive ; rickets ; soluble ; splenomegaly ; steatorrhea ; synthesis ; vitamins You may find definitions for these and ...

  17. Genetics Home Reference: Congenital bile acid synthesis defect type 2

    Science.gov (United States)

    ... chronic ; cirrhosis ; clotting ; congenital ; deficiency ; dehydrogenase ; digestion ; digestive ; enzyme ; failure to thrive ; feces ; gene ; inflammation ; inherited ; intestine ; jaundice ; prevalence ; recessive ; rickets ; soluble ; steatorrhea ; synthesis ; vitamins You may find definitions for these and ...

  18. Enantioselective synthesis of triarylmethanes by chiral imidodiphosphoric acids catalyzed Friedel-Crafts reactions.

    Science.gov (United States)

    Zhuo, Ming-Hua; Jiang, Yi-Jun; Fan, Yan-Sen; Gao, Yang; Liu, Song; Zhang, Suoqin

    2014-02-21

    The first enantioselective synthesis of pyrrolyl-substituted triarylmethanes has been accomplished using a novel imidodiphosphoric acid catalyst, which is derived from two (R)-BINOL frameworks with different 3,3'-substituents. This strategy was also expanded to the synthesis of bis(indolyl)-substituted triarylmethanes with high enantioselectivities, which could only be obtained with moderate ee values in previous reports. These two efficient Friedel-Crafts alkylation processes feature low catalyst loading, broad functional group compatibilities, and the potential to provide practical pathways for the synthesis of enantioenriched bioactive triarylmethanes. PMID:24490630

  19. Camphor Sulfonic Acid-hydrochloric Acid Codoped Polyaniline/polyvinyl Alcohol Composite: Synthesis and Characterization

    Scientific Electronic Library Online (English)

    Jorge Enrique, Osorio-Fuente; Carlos, Gómez-Yáñez; María de los Ángeles, Hernández-Pérez; Fidel, Pérez-Moreno.

    2014-03-01

    Full Text Available Se utilizó un sistema de dopaje complementario formado por ácido clorhídrico y ácido canforsulfónico (ACS) en la síntesis in-situ de un material compuesto polianilina (PANI)/alcohol polivi-nílico (APV). Las mediciones de conductividad mostraron que el uso de ACS ya sea como dopante o codopante resul [...] tó en un decremento en la conductividad total de hasta 2 órdenes de magnitud así como una mejora en la estabilidad térmica. Los compósitos PANi/APV fueron caracterizados mediante análisis térmicos y espectroscópicos. La formación de la sal esmeraldina conductora fue confirmada por espectroscopia UV-Visible e Infrarroja de Transformada de Fourier. El análisis microestructural se llevó a cabo por MEB. Abstract in english A complementary dopant system formed by hydrochloric and camphor sulfonic (CSA) acids was used in the in-situ synthesis of a polyaniline (PANi)/polyvinyl alcohol (PVA) composite. The conductivity measurements showed that the use of CSA either as single dopant or codopant caused a decrement up to 2 o [...] rders of magnitude on the overall conductivity as well as an improvement on thermal stability. The PANi/PVA composites were characterized by spectro-scopic and thermal analysis. Conducting emeraldine salt formation was confirmed by UV-VIS and FTIR spectroscopy. Microstructure analysis was performed by SEM imaging.

  20. A Convenient Synthesis of Amino Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-05-01

    Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

  1. Synthesis of alpha-hydroxyphosphonic acids from Lesquerella oil

    Science.gov (United States)

    Lesquerella oil has been a substance of growing chemical interest, due to the ease with which it is produced and its similarity in structure to castor oil. The primary fatty acid in Lesquerella oil, lesquerolic acid, is very similar to the principal component of castor oil, ricinoleic acid, and may ...

  2. A Convenient Synthesis of Amino Acid Methyl Esters

    OpenAIRE

    Yaowu Sha; Jiabo Li

    2008-01-01

    A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

  3. A convenient procedure for the solid-phase synthesis of hydroxamic acids on PEGA resins

    DEFF Research Database (Denmark)

    Nandurkar, Nitin Subhash; Petersen, Rico

    2011-01-01

    An efficient method for the solid-phase synthesis of hydroxamic acids is described. The method comprises the nucleophilic displacement of esters immobilized on PEGA resins with hydroxylamine/sodium hydroxide in isopropanol. The hydroxyaminolysis protocol is compatible with a broad range of PEGA-supported peptide and peptidomimetic esters. The methodology was found to be compatible with two new strategies for the synthesis of solid-supported lactams and diketopiperazines, respectively, both relying on the high inter- and intramolecular reactivity of cyclic N-acyliminium ions with electron-rich aromatics and heteroaromatics, ultimately affording hydroxamic acid derivatives in high purities.

  4. Communic Acids: Occurrence, Properties and Use as Chirons for the Synthesis of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Alejandro F. Arteaga

    2012-02-01

    Full Text Available Communic acids are diterpenes with labdane skeletons found in many plant species, mainly conifers, predominating in the genus Juniperus (fam. Cupresaceae. In this review we briefly describe their distribution and different biological activities (anti- bacterial, antitumoral, hypolipidemic, relaxing smooth muscle, etc.. This paper also includes a detailed explanation of their use as chiral building blocks for the synthesis of bioactive natural products. Among other uses, communic acids have proven useful as chirons for the synthesis of quassinoids (formal, abietane antioxidants, ambrox and other perfume fixatives, podolactone herbicides, etc., featuring shorter and more efficient processes.

  5. 75 FR 69400 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...

    Science.gov (United States)

    2010-11-12

    ...Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty order on polyethylene terephthalate film, sheet and strip...December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

  6. 77 FR 14501 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...

    Science.gov (United States)

    2012-03-12

    ...Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...duty (AD) order on polyethylene terephthalate film, sheet and strip...September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

  7. 75 FR 65450 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...

    Science.gov (United States)

    2010-10-25

    ...Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...antidumping duty order on polyethylene terephthalate film, sheet and strip...December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

  8. 75 FR 69629 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Extension...

    Science.gov (United States)

    2010-11-15

    ...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...administrative review on polyethylene terephthalate film, sheet, and strip...of this review. See Polyethylene Terephthalate Film, Sheet, and...

  9. 78 FR 45512 - Polyethylene Terephthalate Film from India and Taiwan: Extension of Time Limits for Preliminary...

    Science.gov (United States)

    2013-07-29

    ...A-533-824, A-583-837] Polyethylene Terephthalate Film from India and Taiwan...duty (AD) orders on polyethylene terephthalate film (PET Film) from...Antidumping Duty Orders on Polyethylene Terephthalate Film from India and...

  10. 77 FR 3730 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, in Part, of Antidumping...

    Science.gov (United States)

    2012-01-25

    ...Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...duty (AD) order on polyethylene terephthalate film, sheet and strip...September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

  11. 78 FR 77649 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates; Preliminary...

    Science.gov (United States)

    2013-12-24

    ...Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty order on polyethylene terephthalate film, sheet, and strip...treated, or primed polyethylene terephthalate film, whether...

  12. 77 FR 1668 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, in Part, of...

    Science.gov (United States)

    2012-01-11

    ...Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...duty (CVD) order on polyethylene terephthalate film, sheet and strip...September 20, 2011. See Polyethylene Terephthalate Film, Sheet and...

  13. 78 FR 78333 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...

    Science.gov (United States)

    2013-12-26

    ...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty order on polyethylene terephthalate film, sheet, and strip...Administrative Review: Polyethylene Terephthalate Film, Sheet, and...

  14. 75 FR 52717 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...

    Science.gov (United States)

    2010-08-27

    ...Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...antidumping duty order on polyethylene terephthalate film, sheet and strip...December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

  15. 78 FR 79400 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Initiation...

    Science.gov (United States)

    2013-12-30

    ...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty order on polyethylene terephthalate film, sheet, and strip...antidumping duty order on polyethylene terephthalate film, sheet, and...

  16. 78 FR 50029 - Polyethylene Terephthalate Film, Sheet and Strip From Brazil: Preliminary Results of Antidumping...

    Science.gov (United States)

    2013-08-16

    ...Administration [A-351-841] Polyethylene Terephthalate Film, Sheet and Strip...antidumping duty order on polyethylene terephthalate film, sheet and strip...Administrative Review of Polyethylene Terephthalate Film, Sheet and...

  17. 75 FR 79336 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...

    Science.gov (United States)

    2010-12-20

    ...Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty order on polyethylene terephthalate film, sheet and strip...December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

  18. 75 FR 14423 - Polyethylene Terephthalate Film, Sheet and Strip from Taiwan: Extension of Time Limit for...

    Science.gov (United States)

    2010-03-25

    ...Administration [A-583-837] Polyethylene Terephthalate Film, Sheet and Strip...antidumping duty order on polyethylene terephthalate film, sheet and strip...antidumping order on polyethylene terephthalate film, sheet and...

  19. 77 FR 9892 - Polyethylene Terephthalate Film, Sheet and Strip from India: Preliminary Intent to Rescind...

    Science.gov (United States)

    2012-02-21

    ...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty (CVD) order on polyethylene terephthalate film, sheet and strip...respect to Vacmet and Polypacks. See Polyethylene Terephthalate Film, Sheet and...

  20. 76 FR 76365 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates: Preliminary...

    Science.gov (United States)

    2011-12-07

    ...Trade Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...order on PET Film from the UAE. See Polyethylene Terephthalate Film, Sheet, and...

  1. 75 FR 49902 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Preliminary Results of Antidumping...

    Science.gov (United States)

    2010-08-16

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  2. 77 FR 73428 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...

    Science.gov (United States)

    2012-12-10

    ...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Antidumping Duty Administrative Review: Polyethylene Terephthalate Film, Sheet, and...

  3. 75 FR 81570 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...

    Science.gov (United States)

    2010-12-28

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...under the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  4. 76 FR 76941 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-12-09

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  5. 75 FR 49900 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Preliminary Results of Antidumping...

    Science.gov (United States)

    2010-08-16

    ...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...order on PET film from Brazil. See Polyethylene Terephthalate Film, Sheet, and...

  6. 77 FR 73010 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates; Preliminary...

    Science.gov (United States)

    2012-12-07

    ...Trade Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...of raw, pre- treated, or primed polyethylene terephthalate film, whether...

  7. 77 FR 14493 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...

    Science.gov (United States)

    2012-03-12

    ...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty administrative review of polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  8. 76 FR 9745 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-02-22

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from Taiwan. See Polyethylene Terephthalate Film, Sheet, and...

  9. 76 FR 40325 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Preliminary Results...

    Science.gov (United States)

    2011-07-08

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...no later than June 30, 2011. See Polyethylene Terephthalate Film, Sheet, and...

  10. 78 FR 35245 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...

    Science.gov (United States)

    2013-06-12

    ...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  11. 78 FR 48143 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...

    Science.gov (United States)

    2013-08-07

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Antidumping Duty Administrative Review: Polyethylene Terephthalate Film, Sheet, and...

  12. 76 FR 30910 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Countervailing...

    Science.gov (United States)

    2011-05-27

    ...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet, and Strip...results of the new shipper review of polyethylene terephthalate film, sheet and strip...Background Since the issuance of Polyethylene Terephthalate Film, Sheet, and...

  13. 77 FR 46704 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Preliminary Results of Antidumping...

    Science.gov (United States)

    2012-08-06

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  14. 75 FR 75172 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Final Results of Antidumping Duty...

    Science.gov (United States)

    2010-12-02

    ...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...interested parties to comment. See Polyethylene Terephthalate Film, Sheet, and...

  15. 76 FR 72676 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-11-25

    ...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...interested parties to comment. See Polyethylene Terephthalate Film, Sheet, and...

  16. 75 FR 49893 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...

    Science.gov (United States)

    2010-08-16

    ...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See also Polyethylene Terephthalate Film, Sheet, and...

  17. 76 FR 27005 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Initiation and...

    Science.gov (United States)

    2011-05-10

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...of Sales at Less Than Fair Value: Polyethylene Terephthalate Film, Sheet, and...

  18. 78 FR 9670 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Administrative...

    Science.gov (United States)

    2013-02-11

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  19. 76 FR 71512 - Polyethylene Terephthalate Film, Sheet, and Strip From Korea: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-11-18

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  20. 75 FR 10758 - Polyethylene Terephthalate Film, Sheet and Strip from India: Initiation of Antidumping Duty and...

    Science.gov (United States)

    2010-03-09

    ...Administration [A-533-824, C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty (CVD) orders on Polyethylene Terephthalate Film, Sheet and Strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  1. 76 FR 76948 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Countervailing...

    Science.gov (United States)

    2011-12-09

    ...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet, and Strip...results of the administrative review of polyethylene terephthalate film, sheet and strip...Background Since the issuance of Polyethylene Terephthalate Film, Sheet, and...

  2. 76 FR 57715 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Revocation of...

    Science.gov (United States)

    2011-09-16

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...existing antidumping duty order on polyethylene terephthalate film, sheet, and...

  3. 75 FR 78968 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates: Preliminary...

    Science.gov (United States)

    2010-12-17

    ...Trade Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...order on PET Film from the UAE. See Polyethylene Terephthalate Film, Sheet, and...

  4. 78 FR 48651 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan; Preliminary Results of Antidumping...

    Science.gov (United States)

    2013-08-09

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet and...

  5. 75 FR 40784 - Polyethylene Terephthalate Film, Sheet, and Strip from the Republic of Korea: Preliminary Results...

    Science.gov (United States)

    2010-07-14

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...until no later than July 7, 2010. See Polyethylene Terephthalate Film, Sheet and...

  6. 78 FR 2365 - Polyethylene Terephthalate Film, Sheet and Strip From India: Partial Rescission of Antidumping...

    Science.gov (United States)

    2013-01-11

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...the antidumping duty (AD) order on polyethylene terephthalate film, sheet and strip...Plastics (America), Inc. \\3\\ See Polyethylene Terephthalate (PET) Film,...

  7. 78 FR 48147 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of...

    Science.gov (United States)

    2013-08-07

    ...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet, and Strip...countervailing duty (CVD) order on polyethylene terephthalate film, sheet and strip...gauges of raw, pretreated, or primed polyethylene terephthalate film, sheet and...

  8. 76 FR 47540 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Preliminary Results of Antidumping...

    Science.gov (United States)

    2011-08-05

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  9. 76 FR 9753 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...

    Science.gov (United States)

    2011-02-22

    ...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  10. 76 FR 75870 - Polyethylene Terephthalate Film, Sheet, and Strip From Korea: Notice of Rescission of Antidumping...

    Science.gov (United States)

    2011-12-05

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, [[Page...revocation of the antidumping duty order on polyethylene terephthalate film, sheet, and...

  11. 75 FR 80457 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for...

    Science.gov (United States)

    2010-12-22

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet and strip...through December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

  12. 78 FR 9668 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2013-02-11

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  13. 76 FR 47546 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...

    Science.gov (United States)

    2011-08-05

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  14. 76 FR 18519 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Amended Final Results of...

    Science.gov (United States)

    2011-04-04

    ...Trade Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty administrative review of polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  15. 76 FR 48122 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil: Preliminary Results of Antidumping...

    Science.gov (United States)

    2011-08-08

    ...Trade Administration [A-351-841] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...order on PET film from Brazil. See Polyethylene Terephthalate Film, Sheet, and...

  16. 78 FR 47276 - Polyethylene Terephthalate (PET) Film, Sheet, and Strip From India: Final Results of the...

    Science.gov (United States)

    2013-08-05

    ...Trade Administration [C-533-825] Polyethylene Terephthalate (PET) Film, Sheet...of the countervailing duty order on polyethylene terephthalate (PET) film, sheet...Notice of Countervailing Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  17. 76 FR 61085 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Extension...

    Science.gov (United States)

    2011-10-03

    ...Trade Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...results of the administrative review of polyethylene terephthalate film, sheet, and strip...results of the review by 60 days. See Polyethylene Terephthalate Film, Sheet, and...

  18. 78 FR 67113 - Polyethylene Terephthalate Film, Sheet and Strip From India and Taiwan: Preliminary Results of...

    Science.gov (United States)

    2013-11-08

    ...Administration [A-533-824, A-583-837] Polyethylene Terephthalate Film, Sheet and Strip...review of the antidumping duty orders on Polyethylene Terephthalate Film, Sheet and Strip...Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and...

  19. 76 FR 76943 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-12-09

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  20. 76 FR 30908 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-05-27

    ...Trade Administration [A-533-824] Polyethylene Terephthalate Film, Sheet, and Strip...results of the new shipper review of polyethylene terephthalate film, sheet and strip...Background Since the issuance of Polyethylene Terephthalate Film, Sheet, and...

  1. 77 FR 19634 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission of Countervailing Duty...

    Science.gov (United States)

    2012-04-02

    ...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty (CVD) order on polyethylene terephthalate film, sheet and strip...respect to Vacmet and Polypacks. See Polyethylene Terephthalate Film, Sheet and...

  2. 75 FR 6634 - Polyethylene Terephthalate Film, Sheet, and Strip from India: Final Results of Countervailing...

    Science.gov (United States)

    2010-02-10

    ...Trade Administration [C-533-825] Polyethylene Terephthalate Film, Sheet, and Strip...of the countervailing duty order on polyethylene terephthalate film, sheet, and strip...2007 through December 31, 2007. See Polyethylene Terephthalate Film, Sheet, and...

  3. Effects of acetylsalicylic acid and paracetamol alone and in combination on prostanoid synthesis in man.

    OpenAIRE

    Bippi, H; Frölich, J. C.

    1990-01-01

    1. The present study was designed to investigate the effects of acetylsalicylic acid and paracetamol given separately and in combination on total body and renal PGE2 synthesis in healthy volunteers. 2. In a randomized four-way cross-over study eleven female volunteers received for two consecutive days 3 g day-1 acetylsalicylic acid or 3 g day-1 paracetamol or a combination of 1.5 g day-1 acetylsalicylic acid and 1.5 g day-1 paracetamol, or 1.5 g day-1 acetylsalicylic acid separated by washout...

  4. Stereocontrolled asymmetric synthesis of alpha-hydroxy-beta-amino acids. A stereodivergent approach.

    Science.gov (United States)

    Aoyagi, Y; Jain, R P; Williams, R M

    2001-04-18

    The stereocontrolled asymmetric synthesis of alpha-hydroxy-beta-amino acids has been investigated via the Lewis acid-promoted cyanation of (5R,6S)-2-acetoxy-4-(benzyloxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazines with trimethylsilyl cyanide. Base-catalyzed hydrolysis of the resulting cyano compounds proceeds with excellent stereoselectivity, providing access to diastereomerically pure oxazine-2-carboxylic acids which were readily converted to each enantiomer of the alpha-hydroxy-beta-amino acids isothreonine and nor-C-statine. PMID:11472118

  5. A note on the prebiotic synthesis of organic acids in carbonaceous meteorites

    Science.gov (United States)

    Kerridge, John F.

    1991-01-01

    Strong similarities between monocarboxylic and hydrocarboxylic acids in the Murchison meteorite suggest corresponding similarities in their origins. However, various lines of evidence apparently implicate quite different precursor compounds in the synthesis of the different acids. These seeming inconsistencies can be resolved by postulating that the apparent precursors also share a related origin. Pervasive D enrichment indicates that this origin was in a presolar molecular cloud. The organic acids themselves were probably synthesized in an aqueous environment on an asteroidal parent body, the hydroxy (and amino) acids by means of the Strecker cyanohydrin reaction.

  6. Electron beam induced modification of poly(ethylene terephthalate) films

    Energy Technology Data Exchange (ETDEWEB)

    Vasiljeva, I.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation)]. E-mail: radiant@skylink.spb.ru; Mjakin, S.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation); Makarov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Krasovsky, A.N. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Varlamov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation)

    2006-10-15

    Electron beam processing of poly(ethylene terephthalate) (PET) films is found to promote significant changes in the melting heat, intrinsic viscosity and polymer film-liquid (water, isooctane and toluene) boundary surface tension. These properties are featured with several maximums depending on the absorbed dose and correlating with the modification of PET surface functionality. Studies using adsorption of acid-base indicators and IR-spectroscopy revealed that the increase of PET surface hydrophilicity is determined by the oxidation of methylene and methyne groups. Electron beam treatment of PET films on the surface of N-vinylpyrrolidone aqueous solution provided graft copolymerization with this comonomer at optimum process parameters (energy 700 keV, current 1 mA, absorbed dose 50 kGy)

  7. Electron beam induced modification of poly(ethylene terephthalate) films

    International Nuclear Information System (INIS)

    Electron beam processing of poly(ethylene terephthalate) (PET) films is found to promote significant changes in the melting heat, intrinsic viscosity and polymer film-liquid (water, isooctane and toluene) boundary surface tension. These properties are featured with several maximums depending on the absorbed dose and correlating with the modification of PET surface functionality. Studies using adsorption of acid-base indicators and IR-spectroscopy revealed that the increase of PET surface hydrophilicity is determined by the oxidation of methylene and methyne groups. Electron beam treatment of PET films on the surface of N-vinylpyrrolidone aqueous solution provided graft copolymerization with this comonomer at optimum process parameters (energy 700 keV, current 1 mA, absorbed dose 50 kGy)

  8. Synthesis and mesomorphic behaviour of lithocholic acid derivatives

    Indian Academy of Sciences (India)

    V A E Shaikh; N N Maldar; S V Lonikar

    2003-08-01

    A series of liquid crystalline derivatives of lithocholic acid were prepared using simple chemical reactions involving the terminal functional group—hydroxyl at C-3 and/or carboxyl at C-24. Thus methyl -3-(3-carboxy propionyl) lithocholate (I), 3-(3-carboxy propionyl) lithocholic acid (II), 3-acetyl lithocholic acid (III), 3-propionyl lithocholic acid (IV), 3-benzoyl lithocholic acid (V), 3-(4-nitrobenzoyl) lithocholic acid (VI), 3-cinnamoyl lithocholic acid (VII), methyl-3-(4-nitrobenzoyl) lithocholate (VIII) and 1,4-bis [cholan-24-methoxy carbonyl-3-oxycarbonyl] butane (IX) were prepared in good yields and characterized by IR, NMR and polarizing optical microscopy. Compounds (I) and (IX) exhibited monotropic behaviour while the others were enantiotropic. Some of the compounds also showed a high tendency of super cooling. Compounds (V), (VI) and (IX) formed cholesteric phase while the remaining compounds displayed smectic phase.

  9. Synthesis and radioprotective activity of cinnamic acid thioester derivative

    International Nuclear Information System (INIS)

    In order to find more effective radioprotective agents from cinnamic acid thioester derivatives, the structure of P - hydroxy-cinnamic acid and sinapic acid into 4'-O-carbethoxy-2-chloro-cinnamic acid diethylaminoethylthiol esterhydrochloride and 3, 4, 5,-trimethoxyphenylpropenolic acid diethylamino ethylthiol ester hydrochloride has been changed. The main step of synthesize of these agents involved the condensation of 4'-O-carbethoxy-phenylpropenoic acid chloride with diethylaminoethylthiol under base catalyst. The protective test on mice irradiated with 60Co ?-rays of 7.5?8.0 Gy was shown that the animal survival rate was enhanced by 30% within 30 days after irradiation in comparison with the control group. The MS, IR and NMR spectra data of cinnamic acid thioester derivative have also been reported. The ESR spectra of the compound was discussed

  10. The prebiotic synthesis of amino acids - interstellar vs. atmospheric mechanisms

    Science.gov (United States)

    Meierhenrich, U. J.; Muñoz Caro, G. M.; Schutte, W. A.; Barbier, B.; Arcones Segovia, A.; Rosenbauer, H.; Thiemann, W. H.-P.; Brack, A.

    2002-11-01

    Until very recently, prebiotic amino acids were believed to have been generated in the atmosphere of the early Earth, as successfully simulated by the Urey-Miller experiments. Two independent studies now identified ice photochemistry in the interstellar medium as a possible source of prebiotic amino acids. Ultraviolet irradiation of ice mixtures containing identified interstellar molecules (such as H2O, CO2, CO, CH3OH, and NH3) in the conditions of vacuum and low temperature found in the interstellar medium generated amino acid structures including glycine, alanine, serine, valine, proline, and aspartic acid. After warmup, hydrolysis and derivatization, our team was able to identify 16 amino acids as well as furans and pyrroles. Enantioselective analyses of the amino acids showed racemic mixtures. A prebiotic interstellar origin of amino acid structures is now discussed to be a plausible alternative to the Urey-Miller mechanism.

  11. Control of deoxyribonucleic acid synthesis in normal rabbit colonic mucosa.

    Science.gov (United States)

    Alpers, D H; Philpott, G W

    1975-10-01

    Although cyclic adenosine 3':5'-monophosphate (cyclic AMP, cAMP) is known to suppress DNA synthesis is cultured cells and experimental tumors, its role in normal intact tissue has been little explored. This study helps to define the influence of modifiers of cyclic AMP levels on DNA synthesis in rabbit colonic mucosa maintained in short term organ culture system. Base line studies showed that incorporation of [3H]thymidine into DNA was linear for 24 hr and predominantly in mucosal cells, as shown by autoradiography. Colon from a normal fed rabbit showed a gradient of DNA synthesis, lowest in the cecum and increasing to a maximum, 3-fold greater, at the splenic flexure. This pattern was obliterated by fasting, at which time no formed stool remained in the colon, and all colon mucosa incorporated thymidine at the lower level of the right colon. Known modifiers of intracellular cAMP were found to depress colonic DNA synthesis. Theophylline inhibited DNA synthesis by 35% at 0.5 mM concentration and increased intracellular cAMP levels. This inhibition took 10 hr to be manifest and was at least partly reversible. It was by far the most active of the methylxanthines, consistent with its potency as a phosphodiesterase inhibitor. N6,02-dibutyryl cyclic AMP inhibited DNA synthesis at concentrations as low as 0.025 mM, whereas adenosine and sodium butyrate were ineffective up to 1.0 mM. 5'-AMP did inhibit DNA synthesis, but only at 0.1 mM or higher and did not elevate intracellular cAMP levels. Other modifiers of cAMP which were effective included prostaglandins E1, E2, and F2alpha (2 times 10(-6) M) and papaverine (1 muM). Thymidine uptake was not affected by any of these drugs. The intrinsic thymidine pool was estimated at 20 muM by isotope dilution, and was not altered by theophylline. DNA synthesis in rabbit colon can be suppressed by increased cAMP levels within the time period allowed by organ culture. Thus, these drugs that elevated cAMP levels did not seem to suppress DNA synthesis by decreasing intracellular thymidine concentrations. PMID:170158

  12. Synthesis of racemic, R- and S-[1-11C]-?-hydroxybutyric acid

    International Nuclear Information System (INIS)

    Racemic, R- and S-?-hydroxybutyric acid were labelled with 11C in the carboxylic position by a two-step stereospecific synthesis starting with carrier-added [11C]cyanide and R/S, R- or S-propylene oxide. Hydrolysis of the intermediate nitrile with hydrochloric acid gave racemic [1-11C]-?-hydroxybutyric acid and R- or S-[1-11C]-?-hydroxybutyric acid with an enantiomeric excess of 87-97%. The total synthesis time (including HPLC purification) was 45-50 min from end of trapping. The isolated decay-corrected radiochemical yield was 20-30% based on [11C]cyanide. The radiochemical purity of the products was > 99%]. (author)

  13. Enzymatic synthesis of 11C-pyruvic acid and 11C-L-lactic acid

    International Nuclear Information System (INIS)

    L-Lactic acid is formed as the end product of glycolysis under anaerobic conditions in all cells, but this reaction is of special significance in the myocardium. L-Lactic acid is reversibly formed from and is in equilibrium with myocardial pyruvic acid, which is its sole metabolic pathway. 11C-Pyruvic acid is synthesized from 11C carbon dioxide using pyruvate-ferredoxin oxidoreductase and coenzymes. The 11C-pyruvic acid is then converted to 11-L-lactic acid by lactic acid dehydrogenase. The availability of 11C-pyruvic acid and 11C-L-lactic acid will permit the in vivo investigation of lactate metabolism. (author)

  14. Cesium salts of phosphotungstic acid: Comparison of surface acidity, leaching stability and catalytic activity for the synthesis of ?-ketoenol ethers

    Scientific Electronic Library Online (English)

    Ezzat, Rafiee; Masoud, Kahrizi.

    2013-08-01

    Full Text Available Catalytic activity of Cs xH3-xPW12O40 catalysts were investigated in the synthesis of ?-ketoenol ethers. It was found that activity; acidity, solubility and consequently, recoverability of these catalysts are related to cesium content. A series of ?-ketoenol ether derivatives were synthesized by usi [...] ng Cs25H0.5PW12O40 catalyst in high to excellent yields. This catalyst showed highest surface acidity and lowest solubility in reaction media in comparison with the other cesium content salts.

  15. Bioengineering of Bacterial Polymer Inclusions Catalyzing the Synthesis of N-Acetylneuraminic Acid

    OpenAIRE

    David O. Hooks; Blatchford, Paul A.; Rehm, Bernd H. A.

    2013-01-01

    N-Acetylneuraminic acid is produced by alkaline epimerization of N-acetylglucosamine to N-acetylmannosamine and then subsequent condensation with pyruvate catalyzed by free N-acetylneuraminic acid aldolase. The high-alkaline conditions of this process result in the degradation of reactants and products, while the purification of free enzymes to be used for the synthesis reaction is a costly process. The use of N-acetylglucosamine 2-epimerase has been seen as an alternative to the alkaline epi...

  16. Physiologic hyperinsulinemia stimulates protein synthesis and enhances transport of selected amino acids in human skeletal muscle.

    OpenAIRE

    Biolo, G; Declan Fleming, R Y; Wolfe, R R

    1995-01-01

    We have investigated the mechanisms of the anabolic effect of insulin on muscle protein metabolism in healthy volunteers, using stable isotopic tracers of amino acids. Calculations of muscle protein synthesis, breakdown, and amino acid transport were based on data obtained with the leg arteriovenous catheterization and muscle biopsy. Insulin was infused (0.15 mU/min per 100 ml leg) into the femoral artery to increase femoral venous insulin concentration (from 10 +/- 2 to 77 +/- 9 microU/ml) w...

  17. Synthesis and pharmacological evaluation of cyclodextrin conjugate prodrug of mefenamic acid

    OpenAIRE

    Dev S; Mhaske Deepali; Kadam S; Dhaneshwar S

    2007-01-01

    In the present investigation mefenamic acid prodrug of ?-cyclodextrins was synthesized. The primary hydroxy group of ?-cyclodextrins was used to block the acid group. The synthesis involved a series of protection and deprotection reaction. The ester was evaluated for stability in simulated gastric and intestinal fluid. The hydrolysis of cyclodextrin conjugate in colon is confirmed by the hydrolysis kinetics studies in rat faecal material. The ester was also evaluated for ulcerogenic...

  18. Somatostatin inhibits gastric acid secretion after gastric mucosal prostaglandin synthesis inhibition by indomethacin in man.

    OpenAIRE

    Mogard, M H; Maxwell, V.; Kovacs, T.; Van Deventer, G; Elashoff, J D; Yamada, T.; Kauffman, G L; Walsh, J.H.

    1985-01-01

    The inhibitory effect of indomethacin, 200 + 200 mg administered per os over 24 hours, on the prostaglandin E2 generative capacity of gastric mucosal tissue was determined in healthy male volunteers. The effect of prostaglandin synthesis inhibition on somatostatin induced suppression of food-stimulated acid secretion was tested. Peptone meal stimulated acid secretion was quantified in five healthy volunteers by intragastric titration with and without indomethacin pretreatment. Somatostatin do...

  19. Asymmetric Synthesis of ?,?-Unsaturated ?-Amino Acids via Efficient Kinetic Resolution with Cinchona Alkaloids

    OpenAIRE

    Hang, Jianfeng; DENG Li

    2009-01-01

    The ?,?-unsaturated amino acids are versatile chiral building blocks and biologically interesting compounds. The asymmetric synthesis of ?,?-unsaturated amino acids presents a challenging task as these compounds are labile toward racemization as well as the undesirable double bond isomerization. An efficient, general and mild kinetic resolution with readily accessible and fully recyclable cinchona alkaloid catalysts has been developed to provide a reliably useful approach toward optically act...

  20. Amino-acid-assisted synthesis and size-dependent magnetic behaviors of hematite nanocubes

    OpenAIRE

    Cao, H; Wang, G; Warner, JH; Watt, AAR

    2008-01-01

    This article reports the amino-acid-assisted synthesis and size-dependent magnetic properties of hematite nanocubes. The products were characterized using x-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM. The magnetic behavior of hematite nanocubes was studied using a vibrating sample magnetometer at room temperature. The sizes of hematite nanocubes were controlled by tuning the reaction parameters. The amino acid has double-hydrophilic fu...

  1. Current dependence on electrical field intensity and temperature in polyethylene terephthalate

    International Nuclear Information System (INIS)

    This article is devoted to current dependence on electrical field intensity and temperature in polyethylene terephthalate. The processes of current passage in polyethylene terephthalate are described.

  2. Development of Escherichia coli MG1655 strains to produce long chain fatty acids by engineering fatty acid synthesis (FAS) metabolism.

    Science.gov (United States)

    Jeon, Eunyoung; Lee, Sunhee; Won, Jong-In; Han, Sung Ok; Kim, Jihyeon; Lee, Jinwon

    2011-06-10

    The goal of this research was to develop recombinant Escherichia coli to improve fatty acid synthesis (FAS). Genes encoding acetyl-CoA carboxylase (accA, accB, accC), malonyl-CoA-[acyl-carrier-protein] transacylase (fabD), and acyl-acyl carrier protein thioesterase (EC 3.1.2.14 gene), which are all enzymes that catalyze key steps in the synthesis of fatty acids, were cloned and over-expressed in E. coli MG1655. The acetyl-CoA carboxylase (ACC) enzyme catalyzes the addition of CO(2) to acetyl-CoA to generate malonyl-CoA. The enzyme encoded by the fabD gene converts malonyl-CoA to malonyl-[acp], and the EC 3.1.2.14 gene converts fatty acyl-ACP chains to long chain fatty acids. All the genes except for the EC 3.1.2.14 gene were homologous to E. coli genes and were used to improve the enzymatic activities to over-express components of the FAS pathway through metabolic engineering. All recombinant E. coli MG1655 strains containing various gene combinations were developed using the pTrc99A expression vector. To observe changes in metabolism, the in vitro metabolites and fatty acids produced by the recombinants were analyzed. The fatty acids (C16) from recombinant strains were produced 1.23-2.41 times higher than that from the wild type. PMID:22112270

  3. Synthesis and Characterization of Molecularly Imprinted Polymers for Phenoxyacetic Acids

    OpenAIRE

    Canping Pan; Tiechun Chen; Fulin Zong; Tao Song; Huiting Zhang

    2008-01-01

    2-methylphenoxyacetic acid (2-MPA), 2-methyl-4-chlorophenxyacetic acid (MCPA) and 4-chlorophenoxyacetic acid (4-CPA) were imprinted to investigate the cross-selectivities of molecularly imprinted polymers (MIPs). The result indicates that 2-MPA, which is similar in shape, size and functionality with phenoxyacetic herbicides, are suitable to be used as a suitable template to prepare the MIPs for retaining phenoxyacetic herbicides. To study the ion-pair interactions between template molecules a...

  4. Synthesis and characterization of molecularly imprinted polymers for phenoxyacetic acids.

    Science.gov (United States)

    Zhang, Huiting; Song, Tao; Zong, Fulin; Chen, Tiechun; Pan, Canping

    2008-01-01

    2-methylphenoxyacetic acid (2-MPA), 2-methyl-4-chlorophenxyacetic acid (MCPA) and 4-chlorophenoxyacetic acid (4-CPA) were imprinted to investigate the cross-selectivities of molecularly imprinted polymers (MIPs). The result indicates that 2-MPA, which is similar in shape, size and functionality with phenoxyacetic herbicides, are suitable to be used as a suitable template to prepare the MIPs for retaining phenoxyacetic herbicides. To study the ion-pair interactions between template molecules and functional monomer 4-vinylpiridine (4-VP), computational molecular modeling was employed. The data indicate that the cross-selectivities of MIPs for phenoxyacetic acid herbicides depend on the binding energies of complexes. PMID:19325723

  5. Synthesis and Characterization of Molecularly Imprinted Polymers for Phenoxyacetic Acids

    Directory of Open Access Journals (Sweden)

    Canping Pan

    2008-01-01

    Full Text Available 2-methylphenoxyacetic acid (2-MPA, 2-methyl-4-chlorophenxyacetic acid (MCPA and 4-chlorophenoxyacetic acid (4-CPA were imprinted to investigate the cross-selectivities of molecularly imprinted polymers (MIPs. The result indicates that 2-MPA, which is similar in shape, size and functionality with phenoxyacetic herbicides, are suitable to be used as a suitable template to prepare the MIPs for retaining phenoxyacetic herbicides. To study the ion-pair interactions between template molecules and functional monomer 4-vinylpiridine (4-VP, computational molecular modeling was employed. The data indicate that the cross-selectivities of MIPs for phenoxyacetic acid herbicides depend on the binding energies of complexes.

  6. 75 FR 53711 - Polyethylene Terephthalate (PET) Film From Korea

    Science.gov (United States)

    2010-09-01

    ...INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-459 (Third Review)] Polyethylene Terephthalate (PET) Film From Korea AGENCY: United States International Trade Commission. ACTION: Institution of a...

  7. Easy synthesis of graphene sheets from alfalfa plants by treatment of nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jiao, E-mail: qujiao@bhu.edu.cn [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013 (China); School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China); Luo, Chunqiu, E-mail: fplj_lcq@163.com [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013 (China); Zhang, Qian; Cong, Qiao [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121013 (China); Yuan, Xing [School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China)

    2013-04-01

    Highlights: ? An easy method for synthesis of graphene sheets using alfalfa plants was introduced. ? An novelty formation mechanism of graphene sheets using alfalfa plants was proposed. ? This method exploits a new carbon source and provides a novel idea to synthesize graphene sheets. -- Abstract: This letter focuses on synthesis of graphene sheets from alfalfa plants by treatment of nitric acid. The transmission electron microscopy image (TEM) demonstrates that the graphene sheets are agglomerated and overlapped, the energy dispersive spectrum (EDS) indicates that the products are pure, and the Raman spectrum shows the graphene sheets are well graphitized. In addition, the formation mechanism of the graphene sheets from alfalfa plants by treatment nitric acid is discussed. These findings inspire the search for a new strategy for synthesis of graphene sheets from renewable natural products, and the lower cost of this new process and carbon source may facilitate industrial production.

  8. Easy synthesis of graphene sheets from alfalfa plants by treatment of nitric acid

    International Nuclear Information System (INIS)

    Highlights: ? An easy method for synthesis of graphene sheets using alfalfa plants was introduced. ? An novelty formation mechanism of graphene sheets using alfalfa plants was proposed. ? This method exploits a new carbon source and provides a novel idea to synthesize graphene sheets. -- Abstract: This letter focuses on synthesis of graphene sheets from alfalfa plants by treatment of nitric acid. The transmission electron microscopy image (TEM) demonstrates that the graphene sheets are agglomerated and overlapped, the energy dispersive spectrum (EDS) indicates that the products are pure, and the Raman spectrum shows the graphene sheets are well graphitized. In addition, the formation mechanism of the graphene sheets from alfalfa plants by treatment nitric acid is discussed. These findings inspire the search for a new strategy for synthesis of graphene sheets from renewable natural products, and the lower cost of this new process and carbon source may facilitate industrial production

  9. Asymmetric synthesis of beta-haloaryl beta-amino acid derivatives

    OpenAIRE

    Bull, SD; Davies, SG; Delgado-Ballester, S; Kelly, PM; Kotchie, LJ; Gianotti, M; Laderas, M; Smith, AD

    2001-01-01

    Lithium N-benzyl-N-?-methyl-4-methoxybenzylamide may be employed as a homochiral ammonia equivalent for the synthesis of homochiral ?-haloaryl ?-amino acid derivatives via a strategy involving its conjugate addition to ?,?-unsaturated ?-haloaryl acceptors and subsequent oxidative deprotection with ceric ammonium nitrate.

  10. Synthesis of Novel N-9-Substituted Purine Derivatives from Polymer Supported alpha-Amino Acids.

    Czech Academy of Sciences Publication Activity Database

    Vanda, D.; Jorda, Radek; Lemrová, B.; Volná, T.; Kryštof, Vladimír; McMaster, C.; Soural, M.

    2015-01-01

    Ro?. 17, ?. 7 (2015), s. 426-432. ISSN 2156-8952 R&D Projects: GA MŠk(CZ) LO1204; GA MŠk(CZ) LO1304 Institutional support: RVO:61389030 Keywords : alpha-amino acids * solid-phase synthesis * purine derivatives Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.032, year: 2014

  11. POLYSTYRENE SULFONIC ACID CATALYZED GREENER SYNTHESIS OF HYDRAZONES IN AQUEOUS MEDIUM USING MICROWAVES

    Science.gov (United States)

    An environmentally benign aqueous protocol for the synthesis of cyclic, bi-cyclic, and heterocyclic hydrazones using polystyrene sulfonic acid (PSSA) as a catalyst has been developed; the simple reaction proceeds efficiently in water in the absence of any organic solvent under mi...

  12. Tannic acid Catalyzed an Efficient Synthesis of 2,4,5-Triaryl-1H-Imidazole

    Directory of Open Access Journals (Sweden)

    Shitole Nana Vikram

    2013-05-01

    Full Text Available Tannic acid (C76H52O46 has been found to be an efficient catalyst for one-pot synthesis of 2,4,5-triaryl substituted imidazoles by the reaction of an arylaldehyde, benzyl/benzoin and an ammonium acetate. The short reaction time and excellent yields making this protocol practical and economically attractive.

  13. Synthesis of diphenylmethane from formalin and benzene in a biphasic system with 12-tungstophosphoric acid.

    Science.gov (United States)

    Hou, Z; Okuhara, T

    2001-09-01

    Heteropoly acids such as H3PW12O40 are exceptionally active catalysts in the synthesis of diphenylmethane from benzene and formalin (aqueous formaldehyde) in a biphasic system and can be recycled simply by drying the aqueous phase at room temperature. PMID:12240444

  14. Phosphotungstic Acid: An Efficient, Cost-effective and Recyclable Catalyst for the Synthesis of Polysubstituted Quinolines

    OpenAIRE

    Sahareh Bashiribod; Minoo Dabiri

    2009-01-01

    Phosphotungstic acid (H3PW12O40) was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedländer condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions.

  15. Phosphotungstic Acid: An Efficient, Cost-effective and Recyclable Catalyst for the Synthesis of Polysubstituted Quinolines

    Directory of Open Access Journals (Sweden)

    Sahareh Bashiribod

    2009-03-01

    Full Text Available Phosphotungstic acid (H3PW12O40 was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedländer condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions.

  16. ULTRASOUND-MEDIATED SYNTHESIS PYRAZINE-2-CARBOXYLAMINO ACIDS AND DIPEPTIDES AS POTENT INSECTICIDAL AND

    OpenAIRE

    Malipeddi Venkataramana; Malipeddi Himaja; Mathur Shaifali; Kilaru Jagadeesh Prathap; V Saisaraswathi

    2010-01-01

    A series of pyrazine-2-carboxylamino acids and dipeptides were synthesized by solution-phase peptide synthesis by conventional as well as by using an ultrasonic bath-type sonicator. The reaction time was drastically reduced by sonication with good yields. The synthesized compounds were characterized by IR, 1H NMR and Mass spectral analysis and evaluated for anthelmintic and insecticidal activities.

  17. Dialdehyde-containing nucleic acids and their components: synthesis, properties and affinity modification of proteins

    International Nuclear Information System (INIS)

    Synthesis, structure and chemical properties of nucleoside dialdehyde derivatives are described. The introduction of aldehyde groups into oligonucleotides is discussed. The methods of affinity modification of proteins with periodate-oxidised nucleic acid derivatives are considered. The bibliography includes 48 references.

  18. Synthesis and biological evaluation of new salicylate macrolactones from anacardic acids

    International Nuclear Information System (INIS)

    In connection with our ongoing investigation in the search for new bioactive compounds using non-isoprenoid phenolic lipids from Anacardium occidentale as starting material, we describe the synthesis and cytotoxicity screening of some novel salicylate macrolactones prepared from anacardic acids, the major constituents of natural cashew nut-shell liquid (CNSL). (author)

  19. Phenylboronic acid catalysed synthesis of 1,5-benzodiazepines via cyclocondensation of -phenylenediamine and ketones

    Indian Academy of Sciences (India)

    Santosh V Goswami; Prashant B Thorat; Sudhakar R Bhusare

    2013-07-01

    Phenylboronic acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepine derivatives via cyclocondensation of -phenylenediamine and various ketones in good to excellent yields (82-91%) using acetonitrile as solvent at reflux condition. The remarkable advantages offered by this method are easy mild reaction condition, experimental work up and good to excellent yields of products.

  20. Synthesis of microporous polymeric BINOL-deríved phosphoric acids and applications in hetererogeneous asymmetric organocatalysis

    OpenAIRE

    Kundu, Dipti Sankar

    2012-01-01

    This thesis presents synthesis of chiral, catalytically active as well as highly selective organic polymers of intrinsic microporosity for application in asymmetric heterogeneous organocatalysis. To polymerize enantiopure BINOL-derivatives, different organic moieties, containing thiophene unit, were synthesized and substituted on BINOL-backbone. Oxidative coupling reaction under suitable condition provided insoluble solid polymeric materials containing chiral BINOL-phosphoric acid. Other than...

  1. ACID CATALYZED SYNTHESIS OF HYPERBRANCHED POLY(GLYCEROL-DIACID) OLIGOMERS

    Science.gov (United States)

    Novel oligomeric prepolymers were synthesized by acid-catalyzed condensation of glycerol with iminodiacetic, azelaic, or succinic acid. The prepolymers were obtained, on average in 62% yield and were characterized by 13C NMR, 1H NMR, MALDI-TOF mass spectrometry, and GPC. The synthesized oligomers ...

  2. Improved synthesis of isostearic acid using zeolite catalysts

    Science.gov (United States)

    Isostearic acids are unique and important biobased products with superior properties. Unfortunately, they are not widely utilized in industry because they are produced as byproducts from a process called clay-catalyzed oligomerization of tall oil fatty acids. Generally, this clay method results in...

  3. SYNTHESIS OF NEW MULTIFUNCTIONAL POLYOLS FROM AN OLEIC ACID DERIVATIVE

    Science.gov (United States)

    Sophorolipids (SL) can be obtained in abundant yield from fermentation of inexpensive agricultural coproducts. Acid alcoholysis of SL removes the sugar portion to give 17- and 18-hydroxy fatty acid esters, usually stearate and oleate, essentially quantitatively. Linoleic products result when saffl...

  4. Immobilization of silver nanoparticles on polyethylene terephthalate

    OpenAIRE

    Reznickova, Alena; Novotna, Zdenka; Kolska, Zdenka; Svorcik, Vaclav

    2014-01-01

    Two different procedures of grafting with silver nanoparticles (AgNP) of polyethylene terephthalate (PET), activated by plasma treatment, are studied. In the first procedure, the PET foil was grafted with biphenyl-4,4?-dithiol and subsequently with silver nanoparticles. In the second one, the PET foil was grafted with silver nanoparticles previously coated with the same dithiol. X-ray photoelectron spectroscopy and electrokinetic analysis were used for characterization of the polymer surface ...

  5. One-Pot Synthesis of Novel Chiral ?-Amino Acid Derivatives by Enantioselective Mannich Reactions Catalyzed by Squaramide Cinchona Alkaloids

    OpenAIRE

    Kankan Zhang; Xueping Liang; Ming He; Jian Wu; Yuping Zhang; Wei Xue; Linhong Jin; Song Yang; Deyu Hu

    2013-01-01

    An ef?cient one-pot synthesis of novel ?-amino acid derivatives containing a thiadiazole moiety was developed using a chiral squaramide cinchona alkaloid as organocatalyst. The reactions afforded chiral ?-amino acid derivatives in moderate yields and with moderate to excellent enantioselectivities. The present study demonstrated for the first time the use of a Mannich reaction catalyzed by a chiral bifunctional organocatalyst for the one-pot synthesis of novel ?-amino acid derivatives bearing...

  6. Albumin and whole-body protein synthesis respond differently to intraperitoneal and oral amino acids.

    Science.gov (United States)

    Tjiong, H L; Fieren, M W; Rietveld, T; Wattimena, J L; Schierbeek, H; Huijmans, J G M; Hop, W C; Swart, G R; van den Berg, J W

    2007-08-01

    Patients with peritoneal dialysis are at risk for malnutrition and hypoalbuminemia, which are indicators of poor outcome. Recently, it was shown that dialysis solutions containing amino acids (AAs) and glucose improve protein anabolism in peritoneal dialysis patients. We determined if the same solutions could increase the fractional synthesis rate of albumin along with whole-body protein synthesis. Changes in the fractional albumin synthetic rate reflect acute change in hepatic albumin synthesis. A random-order cross-over study compared the effects of Nutrineal (AA source) plus Physioneal (glucose) dialysate with Physioneal alone dialysate. Eight patients in the overnight fasting state were compared to 12 patients in the daytime-fed state. Fractional albumin synthetic rate and whole-body protein synthesis were determined simultaneously using a primed-continuous infusion of L-[1-(13)C]-leucine. Fractional albumin synthesis on AAs plus glucose dialysis did not differ significantly from that on glucose alone in the fasting or the fed state. Protein intake by itself (fed versus fasting) failed to induce a significant increase in the fractional synthetic rate of albumin. Conversely, the oral protein brought about a significant stimulation of whole-body protein synthesis. Our findings show that the supply of AAs has different effects on whole-body protein synthesis and the fractional synthetic rate of albumin. PMID:17554255

  7. SYNTHESIS AND PHARMACOLOGICAL SCREENING OF NSUBSTITUTED ANTHRANILIC ACID DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Dileep Tiwari

    2011-06-01

    Full Text Available In the present work eight newly synthesized structurally diverse anthranilic acid derivatives were evaluated for their anti-inflammatory activity against carrageenan induced oedema in albino rats. All the anthranilic acid derivatives were compared for their percentage inhibition of the oedema using control drug phenylbutazone. The desired anthranilic acid derivatives 5-bromo-2-{[5-{[(2E-3-(2- substitutedphenylprop-2-enoyl]amino}-1,3,4,-oxadiazol-2- yl methyl]amino}benzoic acid (compounds 1-4 were synthesized by condensation of 5-bromo-N - (2'-amino acetyl -1',3',4'-oxadiazol-5'-ylmethyl anthranilic acid and substituted aromatic aldehydes, respectively, and the compounds 5-bromo-N – [2'-amino [1"-acetyl-5''- (substitutedaryl-2'-pyrazolin-3"-yl]-1'3'4'-oxadiazol-5'- ylmethyl anthranilic acid (compounds 5-8 were synthesized by the condensation of compounds (1-4 with the hydrazine hydrate in the presence of few drops of glacial acetic acid. Compound 5 was found to be a potent member of this series which showed 51.05% antiinflammatory activity with ED50 of 51.05 mg/kg while phenylbutazone exhibited 47.23% anti-inflammatory activity at the same dose. The structures of the newly synthesized compounds have been established on the basis of spectral (FTIR and 1H-NMR data and elemental analysis.

  8. One pot, rapid and efficient synthesis of water dispersible gold nanoparticles using alpha-amino acids

    International Nuclear Information System (INIS)

    A detailed study on the synthesis of spherical and monodispersed gold nanoparticles (AuNPs) using all of the 20 naturally occurring ?-amino acids has been reported. The synthesized nanoparticles have been further characterized using various techniques such as absorbance spectroscopy, transmission electron microscopy, dynamic light scattering and nuclear magnetic resonance. Size control of the nanoparticles has been achieved by varying the ratio of the gold ion to the amino acid. These monodispersed water soluble AuNPs synthesized using non-toxic, naturally occurring ?-amino acids as reducing and capping/stabilizing agents serve as a remarkable example of green chemistry. (paper)

  9. Asymmetric synthesis of -aminophosphonates: The bio-isosteric analogs of -aminobutyric acid

    Indian Academy of Sciences (India)

    Kalisankar Bera; Dwayaja Nadkarni; Iirishi N N Namboothiri

    2013-05-01

    The properties of aminophosphonates as transition state analogs of amino acids, and as antibacterial, antifungal and antiHIV agents attracted considerable attention in recent years. Although many reviews appeared in the literature covering - and -aminophosphonates, -aminophosphonates did not receive sufficient attention despite the fact that parent -aminophosphonic acid and its derivatives are bio-isosteric analogs of GABA (-amino butyric acid). This review provides a critical summary of the significance of -aminophosphonates and various approaches to their synthesis, with particular emphasis to asymmetric versions.

  10. Monoestolides Synthesis From Ricinoleic-Oleic Acids Using Silicotungstic Acid Sol-Gel Catalyst

    OpenAIRE

    Nor Asikin Mohamad Nordin; Nadia Farhana Adnan; Noraini Hamzah; Wan Nor Roslam Wan Isahak; Jumat Salimon; Mohd Ambar Yarmo

    2011-01-01

    Sol-gel silica-supported hydrated silicotungstic acid (STA sol-gel), prepared by incorporating hydrated silicotungstic acid (STA) into silica via sol-gel technique, was used as an efficient heterogeneous catalyst for condensation reaction of a mixture ricinoleic acid (RA) and oleic acid (OA). The activity and selectivity of STA sol-gel for the condensation reaction of a mixture RA and OA have been investigated and compared with unsupported STA and homogeneous perchloric acid. STA sol-gel and ...

  11. (Al) ZSM-12: Synthesis and Modification of Acid Sites.

    Czech Academy of Sciences Publication Activity Database

    ?ejka, Ji?í; Košová, Gabriela; Žilková, Nad?žda; Hrubá, I.

    Amsterdam : Elsevier, 2002 - (Aiello, R.; Giordano, G.; Testa, F.), s. 247-254 - (Studies in Surface Science and Catalysis.. 142 A). [International FEZA Conference /2./. Taormina (IT), 01.09.2002-05.09.2002] R&D Projects: GA AV ?R IAA4040001; GA AV ?R IBS4040017 Institutional research plan: CEZ:AV0Z4040901 Keywords : zeolite * Al-ZSM-12 * synthesis Subject RIV: CF - Physical ; Theoretical Chemistry

  12. Synthesis of quinoxalines in the presence of heteropoly acids

    Directory of Open Access Journals (Sweden)

    Fatemeh Hakimia

    2013-04-01

    Full Text Available Efficient synthesis of quinoxaline derivatives from the reaction of ?-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced.

  13. Synthesis of quinoxalines in the presence of heteropoly acids

    OpenAIRE

    Fatemeh Hakimia; Bi Bi Fatemeh Mirjalili

    2013-01-01

    Efficient synthesis of quinoxaline derivatives from the reaction of ?-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA) such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced.

  14. Synthesis and characterisation of fatty acid bearing technetium complexes and their precursor stages

    International Nuclear Information System (INIS)

    Over the past 25 years numerous research groups have studied the synthesis of 99mTc-coordinated fatty acids as a means of assessing the metabolic state of individual areas of the heart. Diverse chelate groups have been used for binding the radiometal to a fatty acid skeleton. As yet, however, the use of such 99mTc preparations in nuclear medicine has not been possible due to insufficient accumulation rates and poor substrate recognition during ? oxidation. The present study is therefore intended as a contribution to the study of new developments in technetium coordination chemistry and their suitability for the biocompatible marking of fatty acids. The focal areas of the present study were therefore as follows: synthesis and characterisation of ? functionalised fatty acid derivatives, which according to various coordination concepts should be suitable for binding to technetium; synthesis and structural characterisation of the relevant metal complexes using rhenium, an element similar to technetium in terms of its coordination chemistry which allows experimentation without radioactivity; and transfer of the coordination chemistry of the nonradioactive rhenium reference compound to the no-carrier-added 99mTc complex and provision of suitable 99mTc marked fatty acid preparations for a first assessment in the Langendorff perfused heart model

  15. Scientific Opinion on the safety evaluation of the active substances, terephthalic acid, dimethyl ester , polymer with 1,4-butanediol, cyclized, polymers with glycidyl methacrylate, hydroxyl-terminated polybutadiene, methyl methacrylate and styrene, and cobalt stearate for use in food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2012-10-01

    Full Text Available

    This scientific opinion of EFSA deals with the safety evaluation of the oxygen absorber (terephthalic acid, dimethyl ester, polymer with 1,4-butanediol, cyclized, polymers with glycidyl methacrylate, hydroxyl-terminated polybutadiene, methyl methacrylate and styrene copolymer (CAS No 1223402-34-3, FCM substance No 1005 and the oxidation catalyst cobalt stearate (CAS No 1002-88-6 and FCM Substance No 1004, intended to be used up to a maximum percentage of 1% in polyethylene terephtalate (PET for absorbing oxygen from the food environment. All starting substances of the oxygen absorber formulation and cobalt stearate have been evaluated and approved for use as additives in plastic food contact materials. Methyl methacrylate, glycidyl methacrylate and cobalt stearate were not detected at the detection limits of 0.6, 0.006 and 0.0005 mg/kg food simulant, respectively. Butadiene was not detected in the PET bottles at a detection limit of 0.33 mg/kg plastic. For PET formulated with the maximum 1% of the active copoymer, the migration of the low molecular weight fraction (LMWF of the copolymer was estimated to be less than 35 µg/kg food. The CEF Panel concluded that the use of the copolymer up to 1% w/w in PET for contact with all types of foods at temperature up to 95°C and the use of cobalt stearate as oxidation catalyst in PET, is not of safety concern for the consumer.

  16. Engineered L-serine hydroxymethyltransferase from Streptococcus thermophilus for the synthesis of ?,?-dialkyl-?-amino acids.

    Science.gov (United States)

    Hernandez, Karel; Zelen, Igor; Petrillo, Giovanna; Usón, Isabel; Wandtke, Claudia M; Bujons, Jordi; Joglar, Jesús; Parella, Teodor; Clapés, Pere

    2015-03-01

    ?,?-Disubstituted ?-amino acids are central to biotechnological and biomedical chemical processes for their own sake and as substructures of biologically active molecules for diverse biomedical applications. Structurally, these compounds contain a quaternary stereocenter, which is particularly challenging for stereoselective synthesis. The pyridoxal-5'-phosphate (PLP)-dependent L-serine hydroxymethyltransferase from Streptococcus thermophilus (SHMT(Sth); EC 2.1.2.1) was engineered to achieve the stereoselective synthesis of a broad structural variety of ?,?-dialkyl-?-amino acids. This was accomplished by the formation of quaternary stereocenters through aldol addition of the amino acids D-Ala and D-Ser to a wide acceptor scope catalyzed by the minimalist SHMT(Sth) Y55T variant overcoming the limitation of the native enzyme for Gly. The SHMT(Sth) Y55T variant tolerates aromatic and aliphatic aldehydes as well as hydroxy- and nitrogen-containing aldehydes as acceptors. PMID:25611820

  17. Synthesis and Thermal Properties of Amino Acids Ionic Liquids (AAILS)

    OpenAIRE

    M. Shahrom; C.D. Wilfred

    2014-01-01

    Ionic Liquids (ILs) are organic salts with low melting points (below 100°C) and have been widely promoted as “green solvents” due to their non volatility which results in low impact on the environment and health. Natural occurring amino acids, which are easily obtained, biocompatible and biodegradable, are considered as alternative anions for ILs. Four Amino Acids Ionic Liquids (AAILs) have been synthesized by using 4-vinylbenzyltrimethylammonium, [VBTMA] a...

  18. Vapour phase synthesis of salol over solid acids via transesterification

    Indian Academy of Sciences (India)

    S Z Mohamed Shamshuddin; N Nagaraju

    2010-03-01

    The transesterification of methyl salicylate with phenol has been studied in vapour phase over solid acid catalysts such as ZrO2, MoO3 and SO$^{2-}_4$ or Mo(VI) ions modified zirconia. The catalytic materials were prepared and characterized for their total surface acidity, BET surface area and powder XRD patterns. The effect of mole-ratio of the reactants, catalyst bed temperature, catalyst weight, flowrate of reactants, WHSV and time-on-stream on the conversion (%) of phenol and selectivity (%) of salol has been investigated. A good yield (up to 70%) of salol with 90% selectivity was observed when the reactions were carried out at a catalyst bed temperature of 200°C and flow-rate of 10 mL/h in presence of Mo(VI)/ZrO2 as catalyst. The results have been interpreted based on the variation of acidic properties and powder XRD phases of zirconia on incorporation of SO$^{2-}_4$ or Mo(VI) ions. The effect of poisoning of acid sites of SO$^{2-}_4$ or Mo(VI) ions modified zirconia on total surface acidity, powder XRD phases and catalytic activity was also studied. Possible reaction mechanisms for the formation of salol and diphenyl ether over acid sites are proposed.

  19. Synthesis of new fatty acids amides from aminolysis of fatty acid methyl esters (FAMEs); Sintese de novas amidas graxas a partir da aminolise de esteres metilicos

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carolina R.; Montes D' Oca, Caroline da Ros; Duarte, Rodrigo da C.; Kurz, Marcia H.S.; Primel, Ednei G.; Clementin, Rosilene M.; Villarreyes, Joaquin Ariel M.; Montes D' Oca, Marcelo G., E-mail: dqmdoca@furg.b [Universidade Federal do Rio Grande, RS (Brazil). Escola de Quimica e Alimentos

    2010-07-01

    Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce cytotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs). (author)

  20. Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

  1. Synthesis of starch-g-lactic acid copolymer with high grafting degree catalyzed by ammonia water.

    Science.gov (United States)

    Hu, Yingmo; Tang, Mingru

    2015-03-15

    The study of starch-g-lactic acid copolymer has gained much attention for its completely degradable property, but its intricate synthetic procedure and low graft degree inhibited its further application. In this work, the synthesis of starch-g-lactic acid copolymer was attempted via the catalysis of ammonia water by one-step process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, (13)C NMR and HMBC. The synthetic conditions were optimized as follows, the starch was activated for 2h at 80°C at first, starch and lactic acid with weight ratios of 1:4 reacted for 4h at 90°C in vacuum. The starch-g-lactic acid copolymer can be finally obtained with graft degree of starch 58.9%. PMID:25542110

  2. Synthesis of N-substituted acyclic ?-amino acids and their investigation as GABA uptake inhibitors.

    Science.gov (United States)

    Sitka, Ingolf; Allmendinger, Lars; Fülep, Günther; Höfner, Georg; Wanner, Klaus T

    2013-07-01

    In this publication, we describe the synthesis of new inhibitors for the GABA transporter subtypes GAT1 and especially GAT3. We started with 3-aminopropanoic acid possessing a distinct preference for GAT3 in comparison to GAT1 and furthermore its homolog 3-aminobutanoic acid. A series of respective N-substituted amino acids was synthesized by selective N-monoalkylation of these parent structures with 6 different arylalkyl alcohols via a Mitsunobu-type reaction. The resulting compounds were investigated for their inhibitory potency GABA transporter subtypes. Among all tested compounds the 4,4-diphenylbut-3-enyl substituted 3-aminobutanoic acid (rac)-6b showed highest potency with a pIC50 value of 5.34 at GAT1. Unfortunately, the expected GAT3 potency for 2-[tris(4-methoxyphenyl)methoxy]ethyl substituted derivatives was not as high as observed for the respective nipecotic acid derivatives. PMID:23770450

  3. Convergent synthesis of degradable dendrons based on L-malic acid

    DEFF Research Database (Denmark)

    Meyhoff, Ulrich; Riber, Ulla

    2015-01-01

    New degradable polyester dendrons based on the cellular tricarboxylic acid cycle component L-malic acid were synthesized up to the third generation by convergent synthesis. The dendron wedges could be introduced in a stepwise, highly regioselective fashion. HMBC-NMR revealed that the C1-carbonyl on malic acid was exclusively esterified, before the reaction of the second dendron wedge at C4 took place. Degradation studies on a first generation dendron analyzed by HPLC showed that hydrolytic degradation of the dendron most profoundly takes place at pH 4 and pH 9 with the highest degradation rate at alkaline pH. NMR shows that the dendron degrades to malic acid and fumaric acid derivatives. Preliminary studies performed in the cell culture show low toxicity of the dendrons in concentrations of up to 50 ?g mL-1.

  4. INDOLEACETAMIDE AS AN INTERMEDIATE IN THE SYNTHESIS OF INDOLEACETIC ACID IN PSEUDOMONAS SAVASTANOI.

    Science.gov (United States)

    MAGIE, A R; WILSON, E E; KOSUGE, T

    1963-09-27

    When DL-tryptophan-2-C(14) was incubated with washed cells or cell-free preparations of Pseudomonas savastanoi, two radioactive metabolites were formed. One was identified as indoleacetamide and the second, indoleacetic acid. The amount of indoleacetamide in the reaction mixture increased rapidly during the early stages of incubation; it reached a peak after 15 minutes and declined steadily there-after. Indoleacetic acid, on the other hand, accumulated slowly throughout the incubation period. Cell-free preparations preferentially utilize the L-isomer of tryptophan for the synthesis of indoleacetamide and indoleacetic acid. The results of these experiments suggest, therefore, that P. savastanoi synthesizes indoleacetic acid by the following reactions: L-tryptophan--> indoleacetamide-->indoleacetic acid. PMID:14059783

  5. Synthesis and high pressure liquid chromatography of carbon-11 labeled carboxylic acids: valproic acid and palmitic acid

    International Nuclear Information System (INIS)

    Starting from 11CO2, and using the Grignard reaction, 11C carboxylic acids, valproic and palmitic acid have been synthesised. These acids are particularly useful for myocardium imaging and for studying the in vivo metabolism of fatty acids. (U.K.)

  6. Synthesis and high pressure liquid chromatography of carbon-11 labeled carboxylic acids: valproic acid and palmitic acid

    Energy Technology Data Exchange (ETDEWEB)

    Schmall, B.; Conti, P.S.; Sundoro-Wu, B.; Dahl, J.R.; Jacobsen, J.K.; Lee, R. (Memorial Sloan-Kettering Cancer Center, New York (USA). Biophysics Lab.)

    Starting from /sup 11/CO/sub 2/, and using the Grignard reaction, /sup 11/C carboxylic acids, valproic and palmitic acid have been synthesised. These acids are particularly useful for myocardium imaging and for studying the in vivo metabolism of fatty acids.

  7. Silver Colloid Synthesis in Linear and Branched Anionic Polymer Matrices by Using Ascorbic Acid as Reductant

    Directory of Open Access Journals (Sweden)

    Korychenska O.

    2013-09-01

    Full Text Available Silver colloids were synthesized in linear and branched anionic polymer matrices at different pH reducing by ascorbic acid. The template role of the host polymers in anionic form was studied at pH = 7 and pH = 12. Linear Polyacrylamide and star-like copolymers Dextran-graft-Polyacrylamide after alkaline hydrolysis were used as matrices. Silver colloids were studied by UV-Vis spectrophotometry just after synthesis and in 3 months. It is shown that branched polymer matrices are more efficient in comparison with linear one for in situ silver nanoparticle synthesis. The pH value affects the process of formation was investigated.

  8. Synthesis of asymmetric tetracarboxylic acids and corresponding dianhydrides

    Science.gov (United States)

    Chuang, Chun-Hua (Inventor)

    2008-01-01

    This invention relates to processes for preparing asymmetrical biphenyl tetracarboxylic acids and the corresponding asymmetrical dianhydrides, namely 2,3,3',4'-biphenyl dianhydride (a-BPDA), 2,3,3',4'-benzophenone dianhydride (a-BTDA) and 3,4'-methylenediphthalic anhydride (-MDPA). By cross-coupling reactions of reactive metal substituted o-xylenes or by cross-coupling o-xylene derivatives in the presence of catalysts, this invention specifically produces asymmetrical biphenyl intermediates that are subsequently oxidized or hydrolyzed and oxidized to provide asymmetric biphenyl tetracarboxylic acids in comparatively high yields. These asymmetrical biphenyl tetracarboxylic acids are subsequently converted to the corresponding asymmetrical dianhydrides without contamination by symmetrical biphenyl dianhydrides.

  9. The Use of Supported Acidic Ionic Liquids in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Rita Skoda-Földes

    2014-06-01

    Full Text Available Catalysts obtained by the immobilisation of acidic ionic liquids (ILs on solid supports offer several advantages compared to the use of catalytically active ILs themselves. Immobilisation may result in an increase in the number of accessible active sites of the catalyst and a reduction of the amount of the IL required. The ionic liquid films on the carrier surfaces provide a homogeneous environment for catalytic reactions but the catalyst appears macroscopically as a dry solid, so it can simply be separated from the reaction mixture. As another advantage, it can easily be applied in a continuous fixed bed reactor. In the present review the main synthetic strategies towards the preparation of supported Lewis acidic and Brønsted acidic ILs are summarised. The most important characterisation methods and structural features of the supported ionic liquids are presented. Their efficiency in catalytic reactions is discussed with special emphasis on their recyclability.

  10. High-yield, enzymatic synthesis of 14C- or 3H-labeled 1-O-valproyl-?-D-glucopyranuronic acid, the main metabolite of valproic acid in human

    International Nuclear Information System (INIS)

    A simple and high yield synthesis of radiolabeled 1-O-valproyl-?-D-glucopyranuronic acid was developed with the use of UDP-glucuronosyltransferase. Valproic acid, UDP-glucuronic acid, and UDP-glucuronosyltransferase were incubated for 48 h at an optimum pH of 8.5. The enzymatic synthesis followed by column purification gave 51.8% and 52.5% yields of 14C- and 3H- labeled 1-O-valproyl-?-D-glucopyranuronic acid, respectively. The radiochemical purities of the 14C- and 3H-labeled substances were 98.8% and 99.2%, respectively. In contrast, the chemical synthesis using 2,3,4,6-tetrabenzyl-D-glucopyranose and valproic acid resulted in much lower yield (6.8%). (author)

  11. Novel Enzymatic Synthesis of 3-hydroxybutyric Acid Oligomerswith Inserted Lactobionic Acid Moieties

    OpenAIRE

    Kakasi-Zsurka, S.; Todea, A.; BUT, A.; Paul, C.; Boeriu, C.G.; Nagv, A.; Davidescu, C.M.; Peter, F.

    2011-01-01

    3-Hydroxybutyric acid and lactobionic acid yielded linear and cyclic oligomers in a lipase-catalyzedcondensation polymerization reaction, performed at 80°C in bulk and organic solvent systems. Novozyme435 was the most efficient biocatalyst, and a mixture of t-butanol and dimethylsulfoxide in 80:20 (v/v) ratioprovided the highest copolymer conversions. The highest degree of polymerization reached 7 in case ofcopolymers with inserted lactobionic acid moiety and 11 for the 3-hydroxybutyric acid ...

  12. Convenient synthesis of phosphonodipeptides containing C-terminal ?-aminoalkylphosphonic acids.

    Science.gov (United States)

    Sun, Biyun; Xu, Jiaxi

    2015-07-01

    Phosphonopeptides are important phosphorus analogs of natural peptides and have been widely applied as enzyme inhibitors and antibacterial agents. A series of phosphonodipeptides containing C-terminal ?-aminoalkylphosphonic acids was synthesized in satisfactory to good yields conveniently from 2-(N-benzyloxycarbonylamino)alkanamides, aldehydes, and phosphorus trichloride via Mannich-type reaction and subsequent sequential hydrolysis. The reaction mechanism was proposed and verified by (31)P NMR tracing experiments. The current method is an efficient and convenient method for preparation of phosphonopeptides containing C-terminal ?-aminoalkylphosphonic acids. PMID:25998613

  13. Synthesis and in vitro Cytotoxicity of Novel Ursolic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Yanqiu Meng

    2010-06-01

    Full Text Available In an effort to improve potential hepatoprotective and anti-tumor activities, eight novel ursolic acid (UA derivatives were designed and synthesized with substitution at positions of C-3, C-11and C-28 of UA. Their structures were confirmed using IR, MS and 1H-NMR and elemental analysis. Their in vitro cytotoxicity against various cancer cell lines (HeLa, SKOV3 and BGC-823 was evaluated by the standard MTT assay. Among them, compound 13 exhibited more potent cytotoxicity than ursolic acid.

  14. Synthesis and properties of catalysts prepared from silicomolybdovanadium heteropoly acid

    International Nuclear Information System (INIS)

    Catalytic properties of samples prepared of silicomolybdovanadium heteropoly acid (HPA) have been investigated. The massive catalyst is shown to be comparatively low effective in the reaction of acrolein oxidation to acrylic acid. Impregnation of coarse-dispersed silica gel by the HPA solution results in the formation of active and selective catalyst, whereas low-active catalyst of deep oxidation is formed on the base of high-dispersed silica gel. The obtained data are explained by the formation and stabilization of different forms of vanadium- and molybdenum-containing compounds on the carrier surface

  15. From synthesis to function via iterative assembly of N-methyliminodiacetic acid boronate building blocks.

    Science.gov (United States)

    Li, Junqi; Grillo, Anthony S; Burke, Martin D

    2015-08-18

    The study and optimization of small molecule function is often impeded by the time-intensive and specialist-dependent process that is typically used to make such compounds. In contrast, general and automated platforms have been developed for making peptides, oligonucleotides, and increasingly oligosaccharides, where synthesis is simplified to iterative applications of the same reactions. Inspired by the way natural products are biosynthesized via the iterative assembly of a defined set of building blocks, we developed a platform for small molecule synthesis involving the iterative coupling of haloboronic acids protected as the corresponding N-methyliminodiacetic acid (MIDA) boronates. Here we summarize our efforts thus far to develop this platform into a generalized and automated approach for small molecule synthesis. We and others have employed this approach to access many polyene-based compounds, including the polyene motifs found in >75% of all polyene natural products. This platform further allowed us to derivatize amphotericin B, the powerful and resistance-evasive but also highly toxic last line of defense in treating systemic fungal infections, and thereby understand its mechanism of action. This synthesis-enabled mechanistic understanding has led us to develop less toxic derivatives currently under evaluation as improved antifungal agents. To access more Csp(3)-containing small molecules, we gained a stereocontrolled entry into chiral, non-racemic ?-boryl aldehydes through the discovery of a chiral derivative of MIDA. These ?-boryl aldehydes are versatile intermediates for the synthesis of many Csp(3) boronate building blocks that are otherwise difficult to access. In addition, we demonstrated the utility of these types of building blocks in accessing pharmaceutically relevant targets via an iterative Csp(3) cross-coupling cycle. We have further expanded the scope of the platform to include stereochemically complex macrocyclic and polycyclic molecules using a linear-to-cyclized strategy, in which Csp(3) boronate building blocks are iteratively assembled into linear precursors that are then cyclized into the cyclic frameworks found in many natural products and natural product-like structures. Enabled by the serendipitous discovery of a catch-and-release protocol for generally purifying MIDA boronate intermediates, the platform has been automated. The synthesis of 14 distinct classes of small molecules, including pharmaceuticals, materials components, and polycyclic natural products, has been achieved using this new synthesis machine. It is anticipated that the scope of small molecules accessible by this platform will continue to expand via further developments in building block synthesis, Csp(3) cross-coupling methodologies, and cyclization strategies. Achieving these goals will enable the more generalized synthesis of small molecules and thereby help shift the rate-limiting step in small molecule science from synthesis to function. PMID:26200460

  16. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    Directory of Open Access Journals (Sweden)

    Hartati Hartati

    2013-06-01

    Full Text Available This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively. © 2013 BCREC UNDIP. All rights reservedReceived: 20th January 2013; Revised: 31st March 2013; Accepted: 1st April 2013[How to Cite: Hartati, H., Santoso, M., Triwahyono, S., Prasetyoko, D. (2013. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 14-33. (doi:10.9767/bcrec.8.1.4394.14-33][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4394.14-33] | View in  |

  17. Synthesis and optimization ring opening of monoepoxide linoleic acid using p-toluenesulfonic acid

    OpenAIRE

    SALIMON, Jumat; Abdullah, Bashar Mudhaffar; Rahimi M. Yusop; SALIH, Nadia; Yousif, Emad

    2013-01-01

    Biolubricant base oils, 9,12-hydroxy-10,13-oleioxy-12-octadecanoic acid (HYOOA) was synthesized based on the esterification reaction of Monoepoxide linoleic acid 9(12)-10(13)-monoepoxy 12(9)-octadecanoic acid (MEOA) with oleic acid (OA) and catalyzed by p-Toluenesulfonic acid. The optimum conditions for the experiment using D-optimal design to obtain high yield% of 84.61, conversion% of 83.54 and lowest OOC% of 0.05 were predicted at OA/MEOA ratio of 0.2:1 (mol/mol), PTSA/MEOA ratio of 0.4:1 ...

  18. Synthesis and Physical Properties of Estolide Ester Using Saturated Fatty Acid and Ricinoleic Acid

    OpenAIRE

    Nadia Salih; Bashar Mudhaffar Abdullah; Neeranjini Nallathamby; Jumat Salimon

    2011-01-01

    A study was conveyed to produce estolide ester using ricinoleic acid as the backbone. The ricinoleic acid reacted with saturated fatty acid from C8–C18. These reactions were conducted under vacuum at 60°C for 24?h without solvent. The reaction used acid catalyst, sulphuric acid. The new saturate ricinoleic estolide esters show superior low-temperature properties (?52 ± 0.08°C) and high flash point (>300°C). The yield of the neat estolide esters ranged from 52% to 96%. The viscosity range was...

  19. Synthesis and physical properties of estolide ester using saturated Fatty Acid and ricinoleic Acid.

    Science.gov (United States)

    Salimon, Jumat; Nallathamby, Neeranjini; Salih, Nadia; Abdullah, Bashar Mudhaffar

    2011-01-01

    A study was conveyed to produce estolide ester using ricinoleic acid as the backbone. The ricinoleic acid reacted with saturated fatty acid from C8-C18. These reactions were conducted under vacuum at 60°C for 24?h without solvent. The reaction used acid catalyst, sulphuric acid. The new saturate ricinoleic estolide esters show superior low-temperature properties (-52 ± 0.08°C) and high flash point (>300°C). The yield of the neat estolide esters ranged from 52% to 96%. The viscosity range was 51 ± 0.08 to 86 ± 0.01?cp. These new saturated estolide esters were also compared with saturated branched estolide esters. PMID:22007150

  20. Stereoselective synthesis of amino acid derivatives using carbohydrates as templates

    OpenAIRE

    Kunz, Horst; Sager, Wilfried; Pfrengle, Waldemar; Laschat, Sabine; Schanzenbach, Dirk

    1993-01-01

    Glycosylamines contain the easily cleavable semi-aminal-type N-glycosidic bond. O-Protected glycosylamines, therefore, can advantageously be used as a form of "asymmetric ammonia", for instance, in Strecker syntheses and in Ugi reactions to give amino acid amides as well as in modifications of the Mannich reaction.

  1. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    OpenAIRE

    Sylvain Rault; Jean-Charles Lancelot; Marc-Antoine Bazin; Anne Sophie Voisin-Chiret

    2007-01-01

    A feasibility and chemical study of the coupling conditions of L-ascorbic acidwith ferulic acid derivatives are described on the basis of the known synergistic effects ofmixtures of various antioxidants. Novel L-ascorbic ferulic hybrids linked at the C-3hydroxyl group were prepared with the aim to protect the alcohol function and the enediolsystem.

  2. Exploring the Potential of Fungal Arylacetonitrilases in Mandelic Acid Synthesis.

    Czech Academy of Sciences Publication Activity Database

    Veselá, Alícia Barbara; K?enková, Alena; Martínková, Ludmila

    2015-01-01

    Ro?. 57, ?. 5 (2015), s. 466-474. ISSN 1073-6085 R&D Projects: GA ?R(CZ) GAP504/11/0394 Institutional support: RVO:61388971 Keywords : Fungal arylacetonitrilases * (R)-Mandelic acid manufacture * (R,S)-Mandelonitrile hydrolysis Subject RIV: CE - Biochemistry Impact factor: 1.876, year: 2014

  3. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    Directory of Open Access Journals (Sweden)

    Sylvain Rault

    2007-11-01

    Full Text Available A feasibility and chemical study of the coupling conditions of L-ascorbic acidwith ferulic acid derivatives are described on the basis of the known synergistic effects ofmixtures of various antioxidants. Novel L-ascorbic ferulic hybrids linked at the C-3hydroxyl group were prepared with the aim to protect the alcohol function and the enediolsystem.

  4. Synthesis of 9-oxononanoic acid, a precursor for biopolymers.

    Science.gov (United States)

    Otte, Konrad B; Kirtz, Marko; Nestl, Bettina M; Hauer, Bernhard

    2013-11-01

    Polymers based on renewable resources have become increasingly important. The natural functionalization of fats and oils enables an easy access to interesting monomeric building blocks, which in turn transform the derivative biopolymers into high-performance materials. Unfortunately, interesting building blocks of medium-chain length are difficult to obtain by traditional chemical means. Herein, a biotechnological pathway is established that could provide an environmentally suitable and sustainable alternative. A multiple enzyme two-step one-pot process efficiently catalyzed by a coupled 9S-lipoxygenase (St-LOX1, Solanum tuberosum) and 9/13-hydroperoxide lyase (Cm-9/13HPL, Cucumis melo) cascade reaction is proposed as a potential route for the conversion of linoleic acid into 9-oxononanoic acid, which is a precursor for biopolymers. Lipoxygenase catalyzes the insertion of oxygen into linoleic acid through a radical mechanism to give 9S-hydroperoxy-octadecadienoic acid (9S-HPODE) as a cascade intermediate, which is subsequently cleaved by the action of Cm-9/13HPL. This one-pot process afforded a yield of 73?% combined with high selectivity. The best reaction performance was achieved when lipoxygenase and hydroperoxide lyase were applied in a successive rather than a simultaneous manner. Green leaf volatiles, which are desired flavor and fragrance products, are formed as by-products in this reaction cascade. Furthermore, we have investigated the enantioselectivity of 9/13-HPLs, which exhibited a strong preference for 9S-HPODE over 9R-HPODE. PMID:23934656

  5. First Synthesis of 1,4-Dimethoxy-2-Naphthoxyacetic acid.

    Science.gov (United States)

    Chinea, Kimberly; Banerjee, Ajoy K

    2015-07-01

    2-Acetyl-1-hydroxynaphthalene was converted into 1,4-dimethoxy-2-naphthoxyacetic acid in seven steps (methylation, Bayer-Villiger oxidation, hydrolysis, bromination, methylation, alkylation and hydrolysis). 2-Hydroxy-1,4-naphthoquinone on acetylation, aromatization, methylation and hydrolysis, respectively, also yielded the title compound. PMID:26411019

  6. Versatile synthesis of triptycene Di- and tetracarboxylic acids.

    Czech Academy of Sciences Publication Activity Database

    Rybá?ková, Markéta; B?lohradský, Martin; Holý, Petr; Pohl, Radek; Závada, Ji?í

    -, ?. 12 (2006), s. 2039-2042. ISSN 0039-7881 R&D Projects: GA ?R(CZ) GA203/03/0087 Institutional research plan: CEZ:AV0Z40550506 Keywords : trptycenes * carboxylic acids * oxidations Subject RIV: CC - Organic Chemistry Impact factor: 2.333, year: 2006

  7. Synthesis and antihyperlipidemic activity of piperic acid derivatives.

    Science.gov (United States)

    A, Rong; Bao, Narisu; Sun, Zhaorigetu; Borjihan, Gereltu; Qiao, Yanjiang; Jin, Zhuang

    2015-02-01

    A series of piperic acid derivatives were designed and synthesized from piperine/piperlonguminine, and their antihyperlipidemic activities evaluated in diet-induced hyperlipidemic rats with respect to simvastatin. Two promising analogues 3 and 10 were discovered and their antihyperlipidemic activities were comparable to or better than those of simvastatin. PMID:25920263

  8. Radioactive photoreactive fatty acid analogues: Synthesis, biological utilization and tools for the study of fatty acid transport

    Energy Technology Data Exchange (ETDEWEB)

    Leblanc, P.

    1991-01-01

    The present study focused on the development, synthesis and investigation of the biological activity of a radioactive photoreactive homologous series of fatty acid analogues. The carbene precursor m-diazirinophenol was chosen because of its known photolytic properties. A synthesis of an homologous series of omega tritiated omega hydroxy fatty acids was developed based on the oxidation of commercially available olefins with catalytic amounts of OsO[sub 4] in the presence of NaIO[sub 4] to produce the precursor semialdehydes. The photoreactive homologous series was found to be biologically active both in vitro and in vivo. Using rat liver microsomes it was possible to compare Michaelis-Menten constants with those observed for normal substrates for the production of acyl-CoA derivatives. Furthermore, these derivatives were converted to phosphatidylcholine and phosphatidylethanolamine when the corresponding lysophospholipids were present in the incubation mixture. In vivo investigations consisted of incubating L-cells, a fibroblastic cell line, in culture with the radioactive photoreactive fatty acid analogues. Analyses of the lipid fraction of these cells showed that these analogues were present mostly in phosphatidylcholine and in phosphatidylethanolamine. These phospholipids form the major components of L-cell membranes. The photolysis at 360 nm of cells grown in the presence of these analogues resulted in the radioactive labelling of a large number of proteins presumed to be integral membrane proteins. In a collaborative effort, it was found that upon infection of these cells with vesicular stomatitis virus (VSV), followed by isolation and photolysis of the virions, the viral membrane glycoprotein G was intensely labelled. Prior to photolysis it was demonstrated that radioactivity attached to the G protein corresponded to the nonphotolyzed fatty acid. An Escherichia coli membrane protein was also identified, and a fatty acid diffusion assay was developed.

  9. Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory

    2008-10-15

    The synthesis of nano-crystalline activated fly ash catalyst (AFAC) with crystallite size of 12 nm was carried out by chemical and thermal treatment of fly ash, a waste material generated from coal-burning power plants. Fly ash was chemically activated using sulfuric acid followed by thermal activation at 600{sup o}C. The variation of surface and physico-chemical properties of the fly ash by activation methods resulted in improved acidity and therefore, catalytic activity for acid catalyzed reactions. The AFAC was characterized by X-ray diffraction, FT-IR spectroscopy, N{sub 2}-adsorption-desorption isotherm, scanning electron microscopy, flame atomic absorption spectrophotometry and sulfur content by CHNS/O elemental analysis. It showed amorphous nature due to high silica content (81%) and possessed high BET surface area (120 m{sup 2}/g). The catalyst was found to be highly active solid acid catalyst for liquid phase esterification of salicylic acid with acetic anhydride and methanol giving acetylsalicylic acid and methyl salicylate respectively. A maximum yield of 97% with high purity of acetylsalicylic acid (aspirin) and a very high conversion 87% of salicylic acid to methyl salicylate (oil of wintergreen) was obtained with AFAC. The surface acidity and therefore, catalytic activity in AFAC was originated by increased silica content, hydroxyl content and higher surface area as compared to fly ash. The study shows that coal generated fly ash can be converted into potential solid acid catalyst for acid catalyzed reactions. Furthermore, this catalyst may replace conventional environmentally hazardous homogeneous liquid acids making an ecofriendly; solvent free, atom efficient, solid acid based catalytic process. 27 refs., 5 figs., 2 tabs.

  10. Synthesis and curing of alkyd enamels based on ricinoleic acid

    Directory of Open Access Journals (Sweden)

    Jovi?i? Mirjana C.

    2010-01-01

    Full Text Available A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricinoleic acid were formulated by calculation on alkyd constant. Alkyds were characterized by FTIR and by the determination of acid and hydroxyl numbers. Then synthesized alkyds were made into baking enamels by mixing with melamine-formaldehyde resins (weight ratio of 70:30 based on dried mass. Two types of commercial melamine resins were used: threeisobutoxymethyl melamine-formaldehyde resin (TIMMF and hexamethoxymethyl melamine resin (HMMMF. Prepared alkyd/melamine resin mixtures were cured in a differential scanning calorimeter (DSC under non-isothermal mode. Apparent degree of curing as a function of temperature was calculated from the curing enthalpies. Kinetic parameters of curing were calculated using Freeman-Carroll method. TIMMF resin is more reactive with synthesized alkyds than HMMMF resin what was expected. Alkyd resin with 30 wt% of ricinoleic acid is slightly more reactive than alkyd with 40 wt% of ricinoleic acid, probably because it has the high contents of free hydroxyl and acid groups. The gel content, Tg, thermal stability, hardness, elasticity and impact resistance of coated films cured at 150°C for 60 min were measured. Cured films show good thermal stability since the onset of films thermal degradation determined by thermogravimetric analysis (TGA is observed at the temperatures from 281 to 329°C. Films based on alkyd 30 are more thermal stable than those from alkyd 40, with the same melamine resin. The type of alkyd resin has no significant effect on the gel content and the hardness of film. Hardness of cured film increases with increasing of Tg. The values of the films elasticity are satisfied for all prepared samples and are independent on the type of alkyd or melamine resin. The impact resistances of coated films are very high.

  11. Improved conventional synthesis for 14C-labeled polyglutamates of folic acid

    International Nuclear Information System (INIS)

    The majority of folates existing in nature are of the pteroylpolyglutamyl form and are unable to support Lactobacillus casei growth until the ?-linked glutamyls are digested by conjugase enzymes. Most studies involving folate absorption have utilized monoglutamyl forms of folate, primarily folic acid. Synthetic pteroylpolyglutamates prepared by solid phase or conventional synthesis provided conjugated materials with which to study the absorption and metabolism of natural derivatives; however, the synthetic hepataglutamates support microbiological growth prior to enzymatic hydrolysis whereas the natural conjugates do not. Incomplete purification of intermediate peptides during the synthesis would be the most likely explanation of this growth phenomenon. A modified solution synthesis has been developed which improves upon intermediate peptide condensations, increases product yields, and provides a heptapeptide which does not support microbiological growth until after enzymatic hydrolysis. (author)

  12. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  13. Synthesis and Screening of New Enantiomeracally Enriched Non-Protein (S) and (R)-? -Amino Acids, Peptides and Polymers

    International Science & Technology Center (ISTC)

    Synthesis and Screening of New Potentially Pharmacologically Active Enantiomerically Enriched Non-Protein (S) and (R)-? -Amino Acids, Peptides and Polymers Containing Acetylenic Groups in the Side-Chain Radical

  14. Total synthesis of gracilioether F. Development and application of Lewis acid promoted ketene–alkene [2+2] cycloadditions and late-stage C—H oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Rasik, Christopher M. [Indiana Univ., Bloomington, IN (United States); Brown, M. Kevin [Indiana Univ., Bloomington, IN (United States)

    2014-12-22

    The first synthesis of gracilioether F, a polyketide natural product with an unusual tricyclic core and five contiguous stereocenters, is described. Key steps of the synthesis include a Lewis acid promoted ketene–alkene [2+2] cycloaddition and a late-stage carboxylic acid directed C(sp³)—H oxidation. The synthesis requires only eight steps from norbornadiene.

  15. Synthesis of [19-11C]arachidonic acid

    International Nuclear Information System (INIS)

    The preparation of (all Z)-1,17-dichloro-4,7,10,13-heptadecatraene is reported. The synethesis was performed in five steps with a total yield of 22%, starting from 5-chloro-1-pentyne. The corresponding bisGrignard reagent was used in a copper-mediated coupling reaction with [1-11C]ethyl iodide followed by a carbonation with CO2 to afford [19-11C]arachidonic acid in 23% decay corrected radiochemical yield within 52 min. The radiochemical purity of the final product was 98%. In a typical run starting with 20 GBq [11C]O2, 760 MBq of [1911C] arachidonic acid was obtained, with a specific activity of 1.6 GBq/?mol. (Author)

  16. Synthesis and Thermal Properties of Amino Acids Ionic Liquids (AAILS

    Directory of Open Access Journals (Sweden)

    M. Shahrom

    2014-01-01

    Full Text Available Ionic Liquids (ILs are organic salts with low melting points (below 100°C and have been widely promoted as “green solvents” due to their non volatility which results in low impact on the environment and health. Natural occurring amino acids, which are easily obtained, biocompatible and biodegradable, are considered as alternative anions for ILs. Four Amino Acids Ionic Liquids (AAILs have been synthesized by using 4-vinylbenzyltrimethylammonium, [VBTMA] as the cation and glycine, alanine, serine and proline as the anions. The ILs were characterized by Nuclear Magnetic Resonance (NMR and Fourier Transform Infrared Spectroscopy (FTIR. The thermal degradation behavior was measured by Thermogravimetric Analysis (TGA and glass transition temperature measured by Differential Scanning Coulometry (DSC. The result showed that VBTMA Pro gives the highest thermal stability with 178.29°C.

  17. Polyethylene terephthalate thin films; a luminescence study

    Science.gov (United States)

    Carmona-Téllez, S.; Alarcón-Flores, G.; Meza-Rocha, A.; Zaleta-Alejandre, E.; Aguilar-Futis, M.; Murrieta S, H.; Falcony, C.

    2015-04-01

    Polyethylene Terephthalate (PET) films doped with Rare Earths (RE3+) have been deposited on glass by spray pyrolysis technique at 240 °C, using recycled PET and (RE3+) chlorides as precursors. Cerium, terbium, dysprosium and europium were used as dopants materials, these dopants normally produce luminescent emissions at 450, 545, 573 and 612 nm respectively; the doped films also have light emissions at blue, green, yellow and red respectively. All RE3+ characteristic emissions were observed at naked eyes. Every deposited films show a high transmission in the visible range (close 80% T), films surfaces are pretty soft and homogeneous. Films thickness is around 3 ?m.

  18. Acetyl xylan esterase of Aspergillus ficcum catalyzed the synthesis of peracetic acid from ethyl acetate and hydrogen peroxide.

    Science.gov (United States)

    Park, Seung-Moon

    2011-11-01

    Recombinant acetyl xylan esterase (rAXE) of Aspergillus ficcum catalyzed the synthesis of peracetic acid (PAA) from ethyl acetate and hydrogen peroxide. Ten micrograms of rAXE catalyzed the synthesis of 1.34 mM of PAA, which can be used for the pretreatment of cellulosic biomass in situ. PMID:21824816

  19. REGULATION OF CARDIAC AND SKELETAL MUSCLE PROTEIN SYNTHESIS BY INDIVIDUAL BRANCHED-CHAIN AMINO ACIDS IN NEONATAL PIGS

    Science.gov (United States)

    Skeletal muscle grows at a very rapid rate in the neonatal pig, due in part to an enhanced sensitivity of protein synthesis to the postprandial rise in amino acids. An increase in leucine alone stimulates protein synthesis in skeletal muscle of the neonatal pig; however, the effect of isoleucine and...

  20. Enzymatic synthesis and application of fatty acid ascorbyl esters

    OpenAIRE

    Stojanovi? Marija M.; Carevi? Milica B.; Mihailovi? Mladen D.; Kneževi?-Jugovi? Zorica D.; Petrovi? Slobodan D.; Bezbradica Dejan I.

    2013-01-01

    Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully use...

  1. Synthesis and curing of alkyd enamels based on ricinoleic acid

    OpenAIRE

    Jovi?i? Mirjana C.; Radi?evi? Radmila Ž.; Simendi? Vesna B.

    2010-01-01

    A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricino...

  2. Role of phosphatidic acid in plant galactolipid synthesis

    OpenAIRE

    Dubots, Emmanuelle; Botté, Cyrille; Boudière, Laurence; Yamaryo-Botté, Yoshiki; Jouhet, Juliette; Maréchal, Eric; Block, Maryse A

    2011-01-01

    Phosphatidic acid (PA) is a precursor metabolite for phosphoglycerolipids and also for galactoglycerolipids, which are essential lipids for formation of plant membranes. PA has in addition a main regulatory role in a number of developmental processes notably in the response of the plant to environmental stresses. We review here the different pools of PA dispatched at different locations in the plant cell and how these pools are modified in different growth conditions, particularly during plas...

  3. Synthesis and characterization of solid 2-methoxycinnamylidenepyruvic acid

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, C.T. de; Siqueira, A.B.; Pivatto, M.; Ionashiro, M. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: massaoi@iq.unesp.br; Ionashiro, E.Y. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Quimica

    2008-10-15

    The 2-methoxycinnamylidenepyruvic acid (2-MeO-HCP) was synthesized and characterized for nuclear magnetic resonance ({sup 1}H and {sup 13}C NMR), mass spectrometry (MS), Infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The application of DSC for purity determination is well documented in literature and is used in the analysis of pure organic compounds. The molecular geometry and vibrational frequencies of 2-MeO-HCP have been calculated. (author)

  4. Evolution of Abscisic Acid Synthesis and Signaling Mechanisms

    OpenAIRE

    Hauser, Felix; Waadt, Rainer; Schroeder, Julian I

    2011-01-01

    The plant hormone abscisic acid (ABA) mediates seed dormancy, controls seedling development and triggers tolerance to abiotic stresses, including drought. Core ABA signaling components consist of a recently identified group of ABA receptor proteins of the PYRABACTIN RESISTANCE (PYR)/REGULATORY COMPONENT OF ABA RECEPTOR (RCAR) family that act as negative regulators of members of the PROTEIN PHOSPHATASE 2C (PP2C) family. Inhibition of PP2C activity enables activation of SNF1-RELATED KINASE 2 (S...

  5. Synthesis and study of rare earth complexonates with ethylenediaminedisuccinic acid

    International Nuclear Information System (INIS)

    Solid complexonates with ethylenediaminedisuccinic acid of HMZxnH2O and KMLxnH2O composition are synthesized for the Y, Sc and rare earths. The compounds were studied by different physicochemical methods. According to data on IR and electron spectroscopy the conclusion is made on-COOH-group coordination in protonated HML complexes. The complexes are X-ray amorphous, they have polymeric structure

  6. Recent approaches towards the asymmetric synthesis of ?,?-disubstituted ?-amino acids

    DEFF Research Database (Denmark)

    Vogt, Henning; Brase, S.

    2007-01-01

    The class of alpha,alpha-disubstituted alpha-amino acids has gained considerable attention in the past decades and continues doing so. The ongoing interest in biological and chemical properties of the substance class has inspired the development of many new methodologies for their asymmetric construction, which have not found their way into the general focus of organic chemistry yet. The aim of this review is to provide an overview of the developments in the field since 1998.

  7. The Synthesis and Isolation of N-Tert-Butyl-2-Phenylsuccinamic Acid and N-Tert-Butyl-3-Phenylsuccinamic Acid: An Undergraduate Organic Chemistry Laboratory Experiment

    Science.gov (United States)

    Cesare, Victor; Sadarangani, Ishwar; Rollins, Janet; Costello, Dennis

    2004-01-01

    The facile, high yielding synthesis of phenylsuccinamic acids is described and one of these syntheses, the reaction of phenylsuccinic anhydride with tert-butylamine, is successfully modified and adapted for use in the second-semester organic chemistry laboratory at St. John's University. Succinamic acids are compounds that contain both the amide…

  8. Increase of uric acid synthesis in irradiated chicken's embryos

    International Nuclear Information System (INIS)

    Several important intermediate and end products of uric acid metabolism as well as their corresponding enzymatic reactions were studied in 16 day-old chicken embryos which had been one or more times irradiated or respectively treated with ammonium chloride. After sublethal X-irradiation and at the time of the second irradiation with 800 R, the activity of the glutamine synthetase and the xanthin dehydrogenase in the kidneys of the embryos was increased. In contrast to this the glutamate dehydrogenase activity was moderately decreased. Two hours after the main irradiation the uric acid values as well as the amount of fixed nitrogen in the blood serum of previously-irradiated embryos are noticeably higher than the comparative data in non-previously irradiated animals. The glutamic acid values increase after the second irradiation, but still remain lower than with the non-previously irradiated animals. I achieved concuring ressults when I treated the embryos with ammonium chloride instead of radiation. (orig./MG)

  9. Synthesis of labelled compound of ferulic acid and caffeic acid with tritium

    International Nuclear Information System (INIS)

    Effective components of Chinese traditional herbs consist of many compounds, but some of the compounds usually contain unsaturated carbon-carbon double bonds. The unsaturated organic compounds 3H-Ferulic acid and 3H-Caffeic acid are prepared with their tritiated intermediates made by electric-dischange exposure method, which ensures the compounds contaning double bonds not hydrogenated. The 3H-Ferulic acid is composed of 3H-vanillin and Malonic acid. The 3H-Caffeic acid is composed of 3H-protocatechuyl aldehyde and Malonic acid and the specific activity of the products is 0.2 mCi/mg. The radiochemicaly purity is greater than 90%

  10. Creating carbon-carbon bonds with samarium diiodide for the synthesis of modified amino acids and peptides

    DEFF Research Database (Denmark)

    Ebran, Jean-Philippe; Jensen, Christina M

    2006-01-01

    In this perspective, an overview of our experiences on the application of samarium diiodide in organic synthesis for the preparation of amino acid and peptide analogues is presented. Three different carbon-carbon bond forming reactions are discussed, including side chain introductions, gamma-amino acid synthesis and acyl-like radical additions for the construction of C-C mimics of the peptidic bonds.

  11. l-Amino Acid Ligase from Pseudomonas syringae Producing Tabtoxin Can Be Used for Enzymatic Synthesis of Various Functional Peptides

    OpenAIRE

    Arai, Toshinobu; Arimura, Yasuhiro; Ishikura, Shun; Kino, Kuniki

    2013-01-01

    Functional peptides are expected to be beneficial compounds that improve our quality of life. To address the growing need for functional peptides, we have examined peptide synthesis by using microbial enzymes. l-Amino acid ligase (Lal) catalyzes the condensation of unprotected amino acids in an ATP-dependent manner and is applicable to fermentative production. Hence, Lal is a promising enzyme to achieve cost-effective synthesis. To obtain a Lal with novel substrate specificity, we focused on ...

  12. ENANTIOPURE R(-)-3-AMINOISOBUTYRIC ACID SYNTHESIS USING Pseudomonas aeruginosa AS ENANTIOSPECIFIC BIOCATALYST

    Scientific Electronic Library Online (English)

    M. V. C. B., Cortes; R. R., Menezes; E.G., Oestreicher.

    2015-03-01

    Full Text Available Abstract The main goal of this research was the synthesis of enantiopure R(-)-3-aminoisobutyric acid from dihydrothymine with good yield, high stereospecificity and relative simplicity. Seventy two percent yield of the product was obtained in three steps. Step one consisted of dihydrothymine racemiz [...] ation. Step two was a dihydropyrimidinase reaction involving the Pseudomonas aeruginosa 10145 bacterial strain as the biocatalyst. Step three was performed with a diazotization reaction. The bacteria's enzymes determined the stereochemistry of the process since the diazotization reaction did not interfere at this point. The results of this work provide an interesting method for the production of commercial ?-amino acids from other substituteddihydrothymines.

  13. Microwave-Assisted Synthesis of New Substituted Anilides of Quinaldic Acid

    Directory of Open Access Journals (Sweden)

    Josef Jampilek

    2012-01-01

    Full Text Available In this study a one step method for the preparation of substituted anilides of quinoline-2-carboxylic acid was developed. This efficient innovative approach is based on the direct reaction of an acid or ester with substituted anilines using microwave irradiation. The optimized method was used for the synthesis of a series of eighteen substituted quinoline-2-carboxanilides. The molecular structure of N-(4-bromophenylquinoline-2-carboxamide as a model compound was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group with four molecules within the unit cell and the total structure of the compound can be described as “a slightly screwed boat”.

  14. Biological synthesis of ferulic and sinapic acids labelled with 14C

    International Nuclear Information System (INIS)

    14CH3 labelled ferulic and sinapic acids have been synthesized through an enzymic methylation of caffeic and 5-hydroxyferulic acids using labelled S-adenosyl methionine as 14CH3 donor. The methyltransferases involved which were extracted from stems of Poplar catalyse these reactions with a good efficiency. A purification procedure of 14C S-adenosyl methionine is described which allows the recycling of 14CH3 donor. The yield of the overall process is therefore greatly improved. This method allows the synthesis of products with high specific radioactivity. (author)

  15. N-Heterocyclic carbene/Brønsted acid cooperative catalysis as a powerful tool in organic synthesis

    Directory of Open Access Journals (Sweden)

    Rob De Vreese

    2012-03-01

    Full Text Available The interplay between metals and N-heterocyclic carbenes (NHCs has provided a window of opportunities for the development of novel catalytic strategies within the past few years. The recent successful combination of Brønsted acids with NHCs has added a new dimension to the field of cooperative catalysis, enabling the stereoselective synthesis of functionalized pyrrolidin-2-ones as valuable scaffolds in heterocyclic chemistry. This Commentary will briefly highlight the concept of N-heterocyclic carbene/Brønsted acid cooperative catalysis as a new and powerful methodology in organic chemistry.

  16. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    Directory of Open Access Journals (Sweden)

    Patrick Rabe

    2014-08-01

    Full Text Available Tropodithietic acid (TDA is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus aureus and Vibrio anguillarum for a structure–activity relationship (SAR study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues is presented and the bioactivity of the synthetic compounds is discussed.

  17. Synthesis of ?-amino acid derivatives and peptides via enantioselective addition of masked acyl cyanides to imines.

    Science.gov (United States)

    Yang, Kin S; Rawal, Viresh H

    2014-11-19

    A general, asymmetric synthesis of amino acid derivatives is reported. Masked acyl cyanide (MAC) reagents are shown to be effective umpolung synthons for enantioselective additions to N-Boc-aldimines. The reactions are catalyzed by a modified cinchona alkaloid, which can function as a bifunctional, hydrogen bonding catalyst, and afford adducts in excellent yields (90-98%) and high enantioselectivities (up to 97.5:2.5 er). Unmasking the addition products gives acyl cyanide intermediates that are intercepted by a variety of nucleophiles to afford ?-amino acid derivatives. Notably, the methodology provides an alternative method for peptide bond formation. PMID:25366558

  18. Integrated process of distillation with side reactors for synthesis of organic acid esters

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Chandrakant B; Prindle, John C; Kolah, Aspri; Miller, Dennis J; Lira, Carl T

    2015-11-04

    An integrated process and system for synthesis of organic-acid esters is provided. The method of synthesizing combines reaction and distillation where an organic acid and alcohol composition are passed through a distillation chamber having a plurality of zones. Side reactors are used for drawing off portions of the composition and then recycling them to the distillation column for further purification. Water is removed from a pre-reactor prior to insertion into the distillation column. An integrated heat integration system is contained within the distillation column for further purification and optimizing efficiency in the obtaining of the final product.

  19. Kinetics of acetic acid synthesis from ethanol over a Cu/SiO2 catalyst

    DEFF Research Database (Denmark)

    Voss, Bodil; Schjødt, Niels Christian; Grunwaldt, Jan-Dierk; Andersen, Simon Ivar; Woodley, John

    2011-01-01

    The dehydrogenation of ethanol via acetaldehyde for the synthesis of acetic acid over a Cu based catalyst in a new process is reported. Specifically, we have studied a Cu on SiO2 catalyst which has shown very high selectivity to acetic acid via acetaldehyde compared to competing condensation routes. The dehydrogenation experiments were carried out in a flow through lab scale tubular reactor. Based on 71 data sets a power law kinetic expression has been derived for the description of the dehydrog...

  20. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    DEFF Research Database (Denmark)

    Rabe, Patrick; Klapschinski, Tim A.

    2014-01-01

    Tropodithietic acid (TDA) is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus aureus and Vibrio anguillarum for a structure-activity relationship (SAR) study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues is presented and the bioactivity of the synthetic compounds is discussed.

  1. Design, synthesis and structure of new potential electrochemically active boronic acid-based glucose sensors

    DEFF Research Database (Denmark)

    Norrild, Jens Chr.; Søtofte, Inger

    2002-01-01

    In the course of our investigations on new boronic acid based carbohydrate sensors three new boronic acids 3, 7 and 11 containing a ferrocene moiety were synthesised. Their design includes an intramolecular B-N bonding motif in order to facilitate binding at physiological pH. We report the synthesis of the compounds and our investigations on glucose complexation as studied by C-13 NMR spectroscopy. The crystal structure of 2,4,6-tris[2-(N-ferrocenylmethyl-N-methylaminomethyl) phenyl] boroxin (13...

  2. Synthesis and NMR elucidation of novel octa-amino acid resorcin[4]arenes derivatives

    Scientific Electronic Library Online (English)

    Iman, Elidrisi; Pralav V., Bhatt; Thavendran, Govender; Hendrik G., Kruger; Glenn E. M., Maguire.

    Full Text Available The synthesis of nine novel protected amino acid cavitands is reported. All have four pendant M-undecyl chains and 'headgroups' connected by a two-carbon spacer at eight positions on the aromatic rings. The amino acids employed are glycine, alanine, phenylalanine, leucine, proline, tryptophan, serin [...] e, glutamine and lysine. The structures of the compounds were elucidated using one and two-dimensional NMR techniques which verified that all octa-substituted cavitands have symmetrical C2v conformation at room temperature. These compounds have potential synthetic ion channel applications.

  3. Aqueous citric acid as green reaction media for the synthesis of octahydroxanthenes

    Directory of Open Access Journals (Sweden)

    Camilo A. Navarro D.

    2013-08-01

    Full Text Available A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

  4. Concise and Straightforward Asymmetric Synthesis of a Cyclic Natural Hydroxy-Amino Acid

    Directory of Open Access Journals (Sweden)

    Mario J. Simirgiotis

    2014-11-01

    Full Text Available An enantioselective total synthesis of the natural amino acid (2S,4R,5R-4,5-di-hydroxy-pipecolic acid starting from D-glucoheptono-1, 4-lactone is presented. The best sequence employed as a key step the intramolecular nucleophilic displacement by an amino function of a 6-O-p-toluene-sulphonyl derivative of a methyl D-arabino-hexonate and involved only 12 steps with an overall yield of 19%. The structures of the compounds synthesized were elucidated on the basis of comprehensive spectroscopic (NMR and MS and computational analysis.

  5. Compromised Mitochondrial Fatty Acid Synthesis in Transgenic Mice Results in Defective Protein Lipoylation and Energy Disequilibrium

    OpenAIRE

    Smith, Stuart; Witkowski, Andrzej; Moghul, Ayesha; Yoshinaga, Yuko; Nefedov, Michael; de Jong, Pieter; Feng, Dejiang; Fong, Loren; Tu, Yiping; Hu, Yan; Young, Stephen G.; Pham, Thomas; Cheung, Carling; Katzman, Shana M.; Brand, Martin D.

    2012-01-01

    A mouse model with compromised mitochondrial fatty acid synthesis has been engineered in order to assess the role of this pathway in mitochondrial function and overall health. Reduction in the expression of mitochondrial malonyl CoA-acyl carrier protein transacylase, a key enzyme in the pathway encoded by the nuclear Mcat gene, was achieved to varying extents in all examined tissues employing tamoxifen-inducible Cre-lox technology. Although affected mice consumed more food than control animal...

  6. NOVEL 3-ACETYLCOUMARIN SCHIFF’S BASE SYNTHESIS FROM DIFFERENT ACID HYDRAZIDE

    Directory of Open Access Journals (Sweden)

    Anees Pangal

    2013-10-01

    Full Text Available A new series of Schiff’s bases, SB1, SB2 and SB3 were synthesized from 3-acetylcoumarin and different acid hydrazides. The 3-acetyl coumarin was synthesized starting from salicylaldehyde and ethylacetoacetate. The structures of the synthesized compounds have been established on the basis of physical and spectral data. They shows a prominent absorption of -(C=N- in FTIR. A survey of existing literature revealed that there are no reports describing the synthesis of such hydrazones.

  7. Lewis Acid Catalyzed Asymmetric Three-Component Coupling Reaction: Facile Synthesis of ?-Fluoromethylated Tertiary Alcohols.

    Science.gov (United States)

    Aikawa, Kohsuke; Kondo, Daisuke; Honda, Kazuya; Mikami, Koichi

    2015-12-01

    A chiral dicationic palladium complex is found to be an efficient Lewis acid catalyst for the synthesis of ?-fluoromethyl-substituted tertiary alcohols using a three-component coupling reaction. The reaction transforms three simple and readily available components (terminal alkyne, arene, and fluoromethylpyruvate) to valuable chiral organofluorine compounds. This strategy is completely atom-economical and results in perfect regioselectivities and high enantioselectivities of the corresponding tertiary allylic alcohols in good to excellent yields. PMID:26486488

  8. Polyanionic Carboxyethyl Peptide Nucleic Acids (ce-PNAs): Synthesis and DNA Binding

    Science.gov (United States)

    Kirillova, Yuliya; Boyarskaya, Nataliya; Dezhenkov, Andrey; Tankevich, Mariya; Prokhorov, Ivan; Varizhuk, Anna; Eremin, Sergei; Esipov, Dmitry; Smirnov, Igor; Pozmogova, Galina

    2015-01-01

    New polyanionic modifications of polyamide nucleic acid mimics were obtained. Thymine decamers were synthesized from respective chiral ?- and ?-monomers, and their enantiomeric purity was assessed. Here, we present the decamer synthesis, purification and characterization by MALDI-TOF mass spectrometry and an investigation of the hybridization properties of the decamers. We show that the modified ?-S-carboxyethyl-T10 PNA forms a stable triplex with polyadenine DNA. PMID:26469337

  9. Synthesis of N-succinyl-L,L-diaminopimelic acid mimetics via selective protection.

    Czech Academy of Sciences Publication Activity Database

    Van?k, Václav; Pícha, Jan; Bud?šínský, Miloš; Šanda, Miloslav; Jirá?ek, Ji?í; Holz, R. C.; Hlavá?ek, Jan

    2010-01-01

    Ro?. 17, ?. 3 (2010), s. 405-409. ISSN 0929-8665 R&D Projects: GA AV ?R IAA400550614; GA MŠk(CZ) LC06077 Institutional research plan: CEZ:AV0Z40550506 Keywords : bacterial enzyme * N-succinyl-L,L-diaminopimelic acid (SDAP) * synthesis of SDAP analogues * selective protection Subject RIV: CC - Organic Chemistry Impact factor: 1.849, year: 2010

  10. Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction

    OpenAIRE

    Elizabeth P. Jones; Peter Jones; White, Andrew J. P.; Barrett, Anthony G.M.

    2011-01-01

    A method was developed for the synthesis of ?-alkyl, ?-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave th...

  11. Synthesis, Crystal Structure and Biological Activity of 2-Hydroxyethylammonium Salt of p-Aminobenzoic Acid

    OpenAIRE

    Crisan, Manuela E.; Bourosh, Paulina; Massimo E. Maffei; Forni, Alessandra; Pieraccini, Stefano; Sironi, Maurizio; Chumakov, Yurii M.

    2014-01-01

    p-Aminobenzoic acid (pABA) plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA). The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surfa...

  12. Apicoplast fatty acid synthesis is essential for organelle biogenesis and parasite survival in Toxoplasma gondii

    OpenAIRE

    Mazumdar, Jolly; H. Wilson, Emma; Masek, Kate; A. Hunter, Christopher; Striepen, Boris

    2006-01-01

    Apicomplexan parasites are the cause of numerous important human diseases including malaria and AIDS-associated opportunistic infections. Drug treatment for these diseases is not satisfactory and is threatened by resistance. The discovery of the apicoplast, a chloroplast-like organelle, presents drug targets unique to these parasites. The apicoplast-localized fatty acid synthesis (FAS II) pathway, a metabolic process fundamentally divergent from the analogous FAS I pathway in humans, represen...

  13. ULTRASOUND-MEDIATED SYNTHESIS PYRAZINE-2-CARBOXYLAMINO ACIDS AND DIPEPTIDES AS POTENT INSECTICIDAL AND

    Directory of Open Access Journals (Sweden)

    Malipeddi Venkataramana

    2010-09-01

    Full Text Available A series of pyrazine-2-carboxylamino acids and dipeptides were synthesized by solution-phase peptide synthesis by conventional as well as by using an ultrasonic bath-type sonicator. The reaction time was drastically reduced by sonication with good yields. The synthesized compounds were characterized by IR, 1H NMR and Mass spectral analysis and evaluated for anthelmintic and insecticidal activities.

  14. Computer simulation aided synthesis of sodium acrylate/acrylic acid superabsorbent polymers

    OpenAIRE

    Gonçalves, Miguel; Pinto, Virgínia; Dias, Rolando; Costa, Mário Rui

    2011-01-01

    The influence of the synthesis conditions on the end use properties of SAPs was experimentally observed. Initial proportion crosslinker/acrylic acid and degree of neutralization are examples of parameters with strong influence in the performance of these materials. The kinetic model developed is able to capture the main features of SAP production. Ongoing research should allow the prediction of elastic properties of this class of materials.

  15. Synthesis of 5-hydroxymethylfurfural (HMF) by acid catalyzed dehydration of glucose-fructose mixtures

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; Ringborg, Rolf Hoffmeyer; Grotkjær, Thomas; Pedersen, Sven; Woodley, John M.

    2015-01-01

    Synthesis of 5-hydroxymethylfurfural (HMF) from hexoses has been studied extensively in the scientific literature. However, a process has yet to be implemented at industrial scale. In this paper the simultaneous dehydration of glucose and fructose was investigated, in order to develop a process allowing the use of the cheapest available source of fructose: high fructose corn syrup. The dehydration was catalyzed by hydrochloric acid and conducted in acetone-water mixtures, which ensured good sele...

  16. Synthesis of an acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters

    Science.gov (United States)

    Moens, Luc (Lakewood, CO)

    1999-01-01

    A process of preparing an acid addition salt of delta-aminolevulinic acid comprising: dissolving a lower alkyl 5-bromolevulinate and an alkali metal diformylamide in an organic solvent selected from the group consisting of acetonitrile, methanol, tetrahydrofuran, 2-methyltetrahydrofuran and methylformate or mixtures thereof to form a suspension of an alkyl 5-(N,N-diformylamino) levulinate ester; and hydrolyzing said alkyl 5-(N,N-diformylamino) levulinate with an inorganic acid to form an acid addition salt of delta-amino levulinic acid.

  17. Construction of recombinant Bacillus subtilis strains for efficient pimelic acid synthesis

    Scientific Electronic Library Online (English)

    Wei-Wei, Zhang; Ming-Ming, Yang; Heng-xin, Li; Dun, Wang.

    2011-11-15

    Full Text Available As a precursor, pimelic acid plays an important role in biotin biosynthesis pathway of Bacillus subtilis. Fermentations supplemented with pimelic acid could improve the production of biotin, however, with a disadvantage-high cost. So it is necessary to improve the biosynthesis of pimelic acid via ge [...] netic engineering in B. subtilis. In this study, we constructed a recombinant B. subtilis strain for improving the synthesis of pimelic acid, in which a maltose-inducible Pglv promoter was inserted into the upstream of the cistron bioI-orf2-orf3 and, meanwhile, flanked by the tandem cistrons via a single crossover event. The copy number of the integrant was amplified by high-concentration resistance screen and increased to 4-5 copies. The production of pimelic acid from multiple copies integrant was about 4 times higher than that from single copy (1017.13 ?g/ml VS. 198.89 ?g/ml). And when induced by maltose the production of pimelic acid was about 2 times of that under non-induction conditions (2360.73 ?g/ml VS. 991.59 ?g/ml). Thus, these results demonstrated that the production of pimelic acid was improved obviously through reconstructed B. subtilis. It also suggested that our expression system provided a convenient source of pimelic acid that would potentially lower the cost of production of biotin from engineered B. subtilis.

  18. ?(9)-Tetrahydrocannabinolic acid synthase production in Pichia pastoris enables chemical synthesis of cannabinoids.

    Science.gov (United States)

    Lange, Kerstin; Schmid, Andreas; Julsing, Mattijs K

    2015-10-10

    ?(9)-Tetrahydrocannabinol (THC) is of increasing interest as a pharmaceutical and bioactive compound. Chemical synthesis of THC uses a laborious procedure and does not satisfy the market demand. The implementation of biocatalysts for specific synthesis steps might be beneficial for making natural product availability independent from the plant. ?(9)-Tetrahydrocannabinolic acid synthase (THCAS) from C. sativa L. catalyzes the cyclization of cannabigerolic acid (CBGA) to ?(9)-tetrahydrocannabinolic acid (THCA), which is non-enzymatically decarboxylated to THC. We report the preparation of THCAS in amounts sufficient for the biocatalytic production of THC(A). Active THCAS was most efficiently obtained from Pichia pastoris. THCAS was produced on a 2L bioreactor scale and the enzyme was isolated by single-step chromatography with a specific activity of 73Ug(-1)total protein. An organic/aqueous two-liquid phase setup for continuous substrate delivery facilitated in situ product removal. In addition, THCAS activity in aqueous environments lasted for only 20min whereas the presence of hexane stabilized the activity over 3h. In conclusion, production of THCAS in P. pastoris Mut(S) KM71 KE1, subsequent isolation, and its application in a two-liquid phase setup enables the synthesis of THCA on a mg scale. PMID:26197418

  19. Synthesis, Preliminary Bioevaluation and Computational Analysis of Caffeic Acid Analogues

    Directory of Open Access Journals (Sweden)

    Zhiqian Liu

    2014-05-01

    Full Text Available A series of caffeic acid amides were designed, synthesized and evaluated for anti-inflammatory activity. Most of them exhibited promising anti-inflammatory activity against nitric oxide (NO generation in murine macrophage RAW264.7 cells. A 3D pharmacophore model was created based on the biological results for further structural optimization. Moreover, predication of the potential targets was also carried out by the PharmMapper server. These amide analogues represent a promising class of anti-inflammatory scaffold for further exploration and target identification.

  20. Synthesis of Ethylene diamine tetra methylene phosphonic acid EDTMP

    International Nuclear Information System (INIS)

    Ethylenediamine tetramethylene phosphonic acid (EDTMP) is one of the most widely used ligands which forms stable complexes with various radionuclides all of which have shown high bone affinity and other favorable pharmacological characteristics in biodistribution studies. The EDTMP is very important precursor in the preparation of radiopharmaceutical kits which is used in the applications for bone diagnosis and therapy was synthesized in one step with Mannich type reaction. The obtained product was fully characterized by its multi-nuclear NMR and IR spectroscopy. The purity of the product was confirmed by HPLC. (author)

  1. Synthesis and scale inhibitor performance of polyaspartic acid.

    Science.gov (United States)

    Liu, Zhengyan; Sun, Yonghong; Zhou, Xiaohui; Wu, Tao; Tian, Ying; Wang, Yingzhan

    2011-06-01

    Polyaspartic acid (PASP) has been extensively studied in recent years as a green scale inhibitor. PASP was synthesized by thermal polycondensation of maleic anhydride and ammonium carbonate in this study. The optimal polycondensation reaction conditions were the raw material (maleic anhydride and ammonium carbonate) molar ratio of 1.0:1.2, the polymerization temperature of 180°C and reaction time of 2.0 hr. The results showed that PASP exhibits very good scale inhibiting performance. The inhibition rate was 95% for calcium carbonate and 90% for calcium sulfate by the application of 5 mg/L PASP. PMID:25084581

  2. Synthesis and properties of catalysts prepared from silicomolybdovanadium heteropoly acid

    International Nuclear Information System (INIS)

    The methods of atomic absorption, derivatography, X-ray diffraction analyses as well as infrared and NMR spectroscopy have been used to investigate the processes of drying and thermal decomposition of massive and silica-gel-supported silicomolybdovanadium heteropoly acid (HPA). It is shown that separation of vanadium-enriched admixture doesn't take place at the drying stage in supported samples as compared to the massive HPA. The carrier displaces the HPA thermal decomposition to the region of lower temperatures, stabilizes molybdenum- and vanadium-containing compounds the more, the higher is the carrier dispersity and the lower is the supported HPA content

  3. Aqueous organocatalyzed aldol reaction of glyoxylic acid for the enantioselective synthesis of ?-hydroxy-?-keto acids

    OpenAIRE

    Navarro Moles, Fernando Javier; Guillena Townley, Gabriela; Nájera Domingo, Carmen

    2013-01-01

    N-Tosyl-(Sa)-binam-L-prolinamide is an efficient catalyst for the aqueous aldol reaction, between glyoxylic acid, as monohydrate or aqueous solution, and ketones. This reaction led to the formation of chiral ?-hydroxy-?-keto carboxylic acids in high levels of diastereo- and enantioselectivities achieving mainly anti aldol products.

  4. THE USE OF FATTY ACID-ESTERS TO ENHANCE FREE ACID SOPHOROLIPID SYNTHESIS

    Science.gov (United States)

    Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentat...

  5. Studies on regulation of fatty acid synthesis by thyroid hormone

    International Nuclear Information System (INIS)

    A decrease in the activity of liver acetyl-CoA carboxylase (EC 6.4.1.2) is demonstrated in rats following intravenous injection of L-thyroxine in near physiological dose (50 ?g/100g). However, administration of larger dose of L-thyroxine causes an increase in the enzyme activity in both normal and thyroidectomized rats. Studies on the synthesis of enzyme protein enumerate that while incorporation of DL-I-14C leucine in the hepatic enzyme is reduced, its incorporation into the total protein in liver is raised with increased dose of thyroxine (150 ?g/100 ?g) administration to the thyroidectomized rats, thereby showing a lower rate of carboxylation of acetyl-CoA. The degradation of enzyme in liver follows a first order reaction in normal and thyroidectomized animals receiving low dose of thyroxine (50 ?g/100g) and only an increased degradation of hepatic acetyl-CoA carboxylase is noticed in thyroidectomized rats injected high dose of hormone (15?g/100g) intravenously. Moreover, a gradual increase in the long-chain acyl-CoA in liver of thyroidectomized groups administered a large dose of L-thyroxine is noticed and the hormone is without any effect on the activity of the enzyme in vitro. (author)

  6. Sulfanilic acid functionalized mesoporous SBA-15: A water-tolerant solid acid catalyst for the synthesis of uracil fused spirooxindoles as antioxidant agents

    Indian Academy of Sciences (India)

    Robabeh Baharfar; Razieh Azimi

    2015-08-01

    Incorporating sulfanilic acid as a hydrophobic Brønsted acid inside the nanospaces of SBA-15 led to a water-tolerant solid acid catalyst, SBA-15-PhSO 3 H, which showed excellent catalytic performance in synthesis of uracil-fused spirooxindoles in aqueous ethanol. The synthesized compounds were evaluated for their antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay.

  7. Biotransformation and Stereoselective Synthesis of Pharmaceutical Molecules from Linoleic Acid

    Directory of Open Access Journals (Sweden)

    Muhammad Nor bin Omar

    2007-01-01

    Full Text Available The biotransformation of linoleic acid 1 using immobilised soybean lipoxygenase in a dimethyl sulfoxide (DMSO containing medium followed by sodium borohydride reduction afforded 13(S-hydroxy-octadeca-9(Z,11(E-dienoic acid 13(S-HODE 2 in 69% yield. After methylation, methyl 13(S-HODE was subjected to epoxidation using tert-butyl hydroperoxide (TBHP in the presence of vanadyl acetylacetonate or titanium (IV isopropoxide with D-(-- or L-(+-diisopropyl tartrate. Epoxidation catalysed by titanium (IV isopropoxide/D-(--isopropyl tartarate gave predominantly epoxide 3 (in 75% yield while treatment of 2 with TBHP in the presence of titanium (IV isopropoxide and L-(+-diisopropyl tartrate gave preferentially epoxide 4 in 73% yield. Meanwhile, epoxidation of 2 with TBHP in the presence of vanadyl acetylacetonate gave predominantly epoxide 3 in 72% yield. The fluoro-derivatives 8, 9 and 10 were obtained in high yield when hydroxy-derivative 2, 3 and 4 were converted into their trimethylsilyl derivatives 5, 6 and 7 before treating with diethylaminosulphur trifluoride. Treatment of epoxide 4 with acetamide in dimethyl formamide (DMF afforded a heterocyclic 2-oxazoline 11 in 73% yield.

  8. Synthesis and characterization of cashew gum/acrylic acid nanoparticles

    International Nuclear Information System (INIS)

    This paper describes the preparation of nanoparticles from cashew gum (CG) and acrylic acid (AA) by free radical polymerization using cerium (IV) ammonium nitrate (CAN) as an initiator. The yields of the nanoparticles (NP) obtained by varying the RCG/AA from 0.5 to 2.0 were between 65 and 40%. The FT-IR spectra of the NP samples showed bands characteristic of the cashew gum spectrum and a new band at 1560 cm-1 assigned to the stretching vibration of COO- groups of polyacrylic acid. On increasing the RCG/AA from 0.5 to 2.0 an increase in particle size was observed. The NP with an RCG/AA of 0.5 were smaller and had higher storage stability than the NP with an RCG/AA of 1.0 or 2.0. The increase in RCG/AA had no significant effect on the zeta potential of the NP in water. The NP were dried and re-dissolved in water to observe the effect of freeze-drying on particle size. For the NP with an RCG/AA of 0.5 an increase in particle size was observed from 71 to 402 nm, however, for the NP with an RCG/AA of 1.0 or 2.0 a small variation in particle diameter was noted. The behavior of the CG/AA NP was also found to be pH sensitive

  9. Trans-10, cis-12 conjugated linoleic acid decreases de novo lipid synthesis in human adipocytes

    DEFF Research Database (Denmark)

    Obsen, Thomas; Faergeman, Nils J

    2012-01-01

    Conjugated linoleic acid (CLA) reduces adiposity in vivo. However, mechanisms mediating these changes are unclear. Therefore, we treated cultures of human adipocytes with trans-10, cis-12 (10,12) CLA, cis-9, trans-11 (9,11) CLA or other trans fatty acids (FA), and measured indices of lipid metabolism. The lipid-lowering effects of 10,12 CLA were unique, as other trans FA did not reduce TG content to the same extent. Using low levels of [(14)C]-CLA isomers, it was shown that both isomers were readily incorporated into acylglycerols and phospholipids, albeit at lower levels than [(14)C]-oleic or [(14)C]-linoleic acids. When using [(14)C]-acetic acid and [(14)C]-pyruvic acid as substrates, 30 ?M 10,12 CLA, but not 9,11 CLA, decreased de novo synthesis of triglyceride, free FA, diacylglycerol, cholesterol esters, cardiolipin, phospholipids and ceramides within 3-24 h. Treatment with 30 ?M 10,12 CLA, but not 9,11 CLA, decreased total cellular lipids within 3 days and the ratio of monounsaturated FA (MUFA) to saturated FA, and increased C18:0 acyl-CoA levels within 24 h. Consistent with these data, stearoyl-CoA desaturase (SCD)-1 mRNA and protein levels were down-regulated by 10,12 CLA within 7-12 h, respectively. The mRNA levels of liver X receptor (LXR)? and sterol regulatory element binding protein (SREBP)-1c, transcription factors that regulate SCD-1, were decreased by 10,12 CLA within 5 h. These data suggest that the isomer-specific decrease in de novo lipid synthesis by 10,12 CLA is due, in part, to the rapid repression of lipogenic transcription factors that regulate MUFA synthesis, suggesting an anti-obesity mechanism unique to this trans FA.

  10. Isoniazid inhibition of mycolic acid synthesis by cell extracts of sensitive and resistant strains of Mycobacterium aurum.

    Science.gov (United States)

    Quémard, A; Lacave, C; Lanéelle, G

    1991-06-01

    Isonicotinic acid hydrazide (isoniazid; INH) inhibition of mycolic acid synthesis was studied by using cell extracts from both INH-sensitive and -resistant strains of Mycobacterium aurum. The cell extract of the INH-sensitive strain was inhibited by INH, while the preparation from the INH-resistant strain was not. This showed that the INH resistance of mycolic acid synthesis was not due to a difference in drug uptake or the level of peroxidase activity (similar in both extracts). As INH did not induce accumulation of any labeled intermediates, it is postulated that the drug acts either on production of labeled chain elongation precursors of mycolic acids or an early step of this elongation. The level of inhibition was not changed by addition of NAD or nicotinamide; thus, INH does not act on mycolic acid synthesis as an NAD antimetabolite. Benzoic or acetic acid hydrazides and known or postulated metabolites of INH (i.e., the corresponding acid, aldehyde, or alcohol) were not inhibitors of cell-free mycolic acid synthesis; the complete structure of INH was required, as already known for inhibition of mycobacterial culture growth. Extracts prepared from INH-treated cells showed reduced mycolic acid synthesis, and the inhibition level was not modified by either extensive dialysis or pyridoxal phosphate. This latter molecule efficiently antagonized INH action by reacting rapidly with INH, as shown by differential spectroscopy. Moreover, pyridoxal phosphate did not release inhibition of INH-treated extracts. It is proposed that INH may covalently react with an essential component of the mycolic acid synthesis system. PMID:1656850

  11. The use of fatty acid esters to enhance free acid sophorolipid synthesis.

    Science.gov (United States)

    Ashby, Richard D; Solaiman, Daniel K Y; Foglia, Thomas A

    2006-02-01

    Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 +/- 4 g/l, 42 +/- 7 g/l and 18 +/- 6 g/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography with atmospheric pressure ionization mass spectrometry (LC/API-MS) showed that Me-Soy resulted in 71% open-chain SLs with 59% of those molecules remaining esterified at the carboxyl end of the fatty acids. Et-Soy and Pro-Soy resulted in 43% and 80% open-chain free-acid SLs, respectively (containing linoleic acid and oleic acid as the principal fatty acid species linked to the sophorose sugar at the omega-1 position), with no evidence of residual esterification. PMID:16555009

  12. Inborn error of amino acid synthesis: human glutamine synthetase deficiency.

    Science.gov (United States)

    Häberle, Johannes; Görg, Boris; Toutain, Annick; Rutsch, Frank; Benoist, Jean-François; Gelot, Antoinette; Suc, Annie-Laure; Koch, Hans Georg; Schliess, Freimut; Häussinger, Dieter

    2006-01-01

    Glutamine synthetase (GS) is ubiquitously expressed in human tissues, being involved in ammonia detoxification and interorgan nitrogen flux. Inherited systemic deficiency of glutamine based on a defect of glutamine synthetase was recently described in two newborns with an early fatal course of disease. Glutamine was largely absent in their serum, urine and cerebrospinal fluid. Each of the patients had a homozygous mutation in the glutamine synthetase gene and enzymatic investigations confirmed that these mutations lead to a severely reduced glutamine synthetase activity. From the observation in the first patients with congenital glutamine synthetase deficiency, brain malformation can be expected as one of the leading signs. In addition, other organ systems are probably involved as observed in one of the index patients who suffered from severe enteropathy and necrolytic erythema of the skin. Deficiency of GS has to be added to the list of inherited metabolic disorders as a rare example of a defect in the biosynthesis of an amino acid. PMID:16763901

  13. Synthesis of nalidixic acid based hydrazones as novel pesticides.

    Science.gov (United States)

    Aggarwal, Nisha; Kumar, Rajesh; Srivastva, Chitra; Dureja, Prem; Khurana, J M

    2010-03-10

    Thirty-one substituted hydrazones of nalidixic acid hydrazide were synthesized and characterized by spectral techniques. These compounds were evaluated for various biological activities, namely, fungicidal, insecticidal, and nitrification inhibitory activities. The antifungal activity was evaluated against five pathogenic fungi, namely, Rhizoctonia bataticola , Sclerotium rolfsii , Rhizoctonia solani , Fusarium oxysporum , and Alternaria porii . They showed maximum inihibition against A. porii with ED(50) = 34.2-151.3 microg/mL. The activity was comparable to that of a commercial fungicide, hexaconazole (ED(50) = 25.4 microg/mL). They were also screened for insecticidal activity against third-instar larvae of Spodoptera litura and adults of Callosobruchus maculatus and Tribollium castaneum . Most of them showed 70-100% mortality against S. litura through feeding method at 0.1% dose. These compounds were not found to be effective nitrification inhibitors. PMID:20131903

  14. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B; Bräuner-Osborne, Hans; Lützhøft, H H; Poulsen, M V; Eriksen, L; Krogsgaard-Larsen, P

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and block...

  15. Reciclagem química do PET pós-consumo: caracterização estrutural do ácido tereftálico e efeito da hidrólise alcalina em baixa temperatura / Chemical Recycling of Post-consumer PET: Structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature

    Scientific Electronic Library Online (English)

    Talitha Granja, Fonseca; Yeda Medeiros Bastos de, Almeida; Glória Maria, Vinhas.

    2014-10-01

    Full Text Available Devido ao impacto ambiental causado pelo descarte de embalagens PET, a reciclagem desse material tem sido bastante discutida e avaliada. Em particular, a reciclagem química viabiliza a obtenção dos monômeros utilizados na fabricação da resina PET: o etilenoglicol (EG) e o ácido tereftálico (PTA). Po [...] r isso, estudos de otimização desse processo são importantes tanto do ponto de vista ambiental, quanto econômico. Neste trabalho foram investigados certos parâmetros que influenciam a reação de despolimerização do PET pós-consumo via hidrólise alcalina, a fim de obter o PTA. Os ensaios foram realizados à temperatura de 70 °C, variando a concentração da solução de hidróxido de sódio e o tempo de reação. Os melhores resultados foram obtidos para concentração de NaOH 10,82 mol L-1 e tempo de reação de 9 h. Consequentemente, foi possível comprovar a viabilidade do processo, uma vez que as análises por infravermelho e Ressonância Magnética Nuclear confirmaram a obtenção do PTA em todas as reações realizadas. Abstract in english Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). There [...] fore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L-1 NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed.

  16. The solubilities of benzene polycarboxylic acids in water

    Energy Technology Data Exchange (ETDEWEB)

    Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Manzurola, Emanuel [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Abo Balal, Nazmia [Negev Academic College of Engineering, Beer Sheva (Israel)

    2006-05-15

    The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities.

  17. The solubilities of benzene polycarboxylic acids in water

    International Nuclear Information System (INIS)

    The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities

  18. Possible involvement of phospholipase C and protein kinase C in stimulatory actions of L-leucine and its keto acid, ?-ketoisocaproic acid, on protein synthesis in RLC-16 hepatocytes

    OpenAIRE

    Yagasaki, Kazumi; Morisaki-Tsuji, Naoko; Miura, Atsuhito; Funabiki, Ryuhei

    2002-01-01

    Effects of leucine and related compounds on protein synthesis were studied in RLC-16 hepatocytes. The incorporation of [3H] tyrosine into cellular protein was measured as an indexof protein synthesis. In leucine-depleted RLC-16 cells, L-leucineand its keto acid, ?-ketoisocaproic acid (KIC), stimulated protein synthesis, while D-leucine did not. Mepacrine, an inhibitor of both phospholipase A2 and C canceled stimulatory actions of L-leucine and KIC on protein synthesis, suggesting a possible i...

  19. Inhibition of protein synthesis may explain the bactericidal properties of hypochlorous acid produced by phagocytic cells

    International Nuclear Information System (INIS)

    The authors find that hypochlorous acid (HOCl) and hydrogen peroxide (H2O2) inhibit protein synthesis in E. coli: HOCl is similarly ordered 10x more efficient than H2O2. This result may underlie the mechanism of bacterial killing by phagocytes, which use H2O2 and myeloperoxidase (MPO) to oxidize Cl- to HOCl. Protein synthesis (3H-leu incorporation) was completely inhibited by 50?M HOCl, whereas 50?M H2O2 only gave similarly ordered 10% inhibition. Complete inhibition by H2O2 was only observed at concentrations 2O2. No growth occurred at 50?M HOCl: in contrast 0.5 mM H2O2 was required for similar results. During time-course experiments it was found that the inhibition of cell growth by both HOCl and H2O2 reached a maximum within 30 min (at any concentration used). HOCl reacts avidly with amino groups to form N-chloroamines but H2O2 is unreactive. Amino acids (ala, lys, met, trp) or taurine (all at 10 mM) prevented the effects of HOCl but did not affect H2O2 results. There was an excellent correlation between decreased protein synthesis and diminished cell growth. Inhibition of cell growth was not explained by proteolysis (release of acid-soluble counts), or by loss of membrane integrity. They propose that inhibition of protein synthesis may be a fundamental aspect of the bactericidal functions of phagocytes, and that the production of HOCl by MPO represents a quantitative advantage over H2O2

  20. TORC1 Inhibits GSK3-Mediated Elo2 Phosphorylation to Regulate Very Long Chain Fatty Acid Synthesis and Autophagy

    DEFF Research Database (Denmark)

    Zimmermann, Christine; Santos, Aline

    2013-01-01

    Very long chain fatty acids (VLCFAs) are essential fatty acids with multiple functions, including ceramide synthesis. Although the components of the VLCFA biosynthetic machinery have been elucidated, how their activity is regulated to meet the cell's metabolic demand remains unknown. The goal of this study was to identify mechanisms that regulate the rate of VLCFA synthesis, and we discovered that the fatty acid elongase Elo2 is regulated by phosphorylation. Elo2 phosphorylation is induced upon inhibition of TORC1 and requires GSK3. Expression of nonphosphorylatable Elo2 profoundly alters the ceramide spectrum, reflecting aberrant VLCFA synthesis. Furthermore, VLCFA depletion results in constitutive activation of autophagy, which requires sphingoid base phosphorylation. This constitutive activation of autophagy diminishes cell survival, indicating that VLCFAs serve to dampen the amplitude of autophagy. Together, our data reveal a function for TORC1 and GSK3 in the regulation of VLCFA synthesis that has important implications for autophagy and cell homeostasis.

  1. Synthesis and characterization of novel n-9 fatty acid conjugates possessing antineoplastic properties.

    Science.gov (United States)

    Khan, Azmat A; Husain, Ahmad; Jabeen, Mumtaz; Mustafa, Jamal; Owais, Mohammad

    2012-10-01

    The present study enumerates the synthesis, spectroscopic characterization, and evaluation of anticancer potential of esters of two n-9 fatty acids viz., oleic acid (OLA) and ricinoleic acid (RCA) with 2,4- or 2,6-diisopropylphenol. The synthesis strategy involved esterification of the hydroxyl group of diisopropylphenol (propofol) to the terminal carboxyl group of n-9 fatty acid. The synthesized propofol-n-9 conjugates having greater lipophilic character were tested initially for cytotoxicity in-vitro. The conjugates showed specific growth inhibition of cancer cell lines whereas no effect was observed in normal cells. In general, pronounced growth inhibition was found against the human skin malignant melanoma cell line (SK-MEL-1). The anticancer potential was also determined by testing the effect of these conjugates on cell migration, cell adhesion and induction of apoptosis in SK-MEL-1 cancer cells. Propofol-OLA conjugates significantly induced apoptosis in contrast to propofol-RCA conjugates which showed only weak signals for cytochrome c. Conclusively, the synthesized novel ester conjugates showed considerable moderation of anti-tumor activity. This preliminary study places in-house synthesized conjugates into the new class of anticancer agents that possess selectivity toward cancer cells over normal cells. PMID:22923370

  2. One-step synthesis of hydrothermally stable mesoporous aluminosilicates with strong acidity

    International Nuclear Information System (INIS)

    Using tetraethylorthosilicate (TEOS), polymethylhydrosiloxane (PMHS) and aluminium isopropoxide (AIP) as the reactants, through a one-step nonsurfactant route based on PMHS-TEOS-AIP co-polycondensation, hydrothermally stable mesoporous aluminosilicates with different Si/Al molar ratios were successfully prepared. All samples exclusively showed narrow pore size distribution centered at 3.6 nm. To assess the hydrothermal stability, samples were subjected to 100 deg. C distilled water for 300 h. The boiled mesoporous aluminosilicates have nearly the same N2 adsorption-desorption isotherms and the same pore size distributions as those newly synthesized ones, indicating excellent hydrothermal stability. The 29Si MAS NMR spectra confirmed that PMHS and TEOS have jointly condensed and CH3 groups have been introduced into the materials. The 27Al MAS NMR spectra indicated that Al atoms have been incorporated in the mesopore frameworks. The NH3 temperature-programmed desorption showed strong acidity. Due to the existence of large amount of CH3 groups, the mesoporous aluminosilicates obtained good hydrophobicity. Owing to the relatively large pore and the strong acidity provided by the uniform four-coordinated Al atoms, the excellent catalytic performance for 1,3,5-triisopropylbenzene cracking was acquired easily. The materials may be a profitable complement for the synthesis of solid acid catalysts. - Graphical abstract: Based on the nonsurfactant method, a facile one-step synthesis route has been developed to prepare methyl-modified mesoporous aluminosilicates that possessed hydrothermal stability and strong acidity

  3. Synthesis of acrylate functional telechelic poly(lactic acid) oligomer by transesterification.

    Science.gov (United States)

    Coullerez, G; Lowe, C; Pechy, P; Kausch, H H; Hilborn, J

    2000-08-01

    The controlled synthesis of low molecular weight (Mn from 700 to 10 000 g/mol) poly(lactic acid) (PLA) telechelic oligomers end-capped with acrylate groups by a one-step reaction was investigated. A transesterification reaction was carried out in solution with a Lewis acid titanium catalyst using a high molecular weight PLA and a low molar mass diacrylate. End-functionalization was demonstrated by proton NMR spectroscopy which was also used for quantitative analysis and number average molecular weight determination using the ratio between the acrylic chain ends to the main groups of poly(D,L-lactic acid). The formation of low molar mass oligomers from high molecular weight poly(lactic acid) was verified by gel permeation chromatography. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry showed that the above oligomerization was accompanied by the formation of cyclic compounds. By these means the feasability of a simple transesterification for a controlled synthesis of telechelic oligomers with molecular mass being a function of the added amount of diacrylate has been demonstrated. The glass transition temperatures of the elaborated oligomers varied from -35 to -5 degrees C. Subsequent thermal crosslinking was performed using benzoyl peroxide which enabled the formation of amorphous networks with Tg's close to the body temperature of 40 degrees C. Upon storage in a humid atmosphere the initially fairly hard and brittle networks became, due to hydrolysis, progressively more flexible thus demonstrating the potential biodegradability of these materials. PMID:15348001

  4. Calorie restriction increases fatty acid synthesis and whole body fat oxidation rates.

    Science.gov (United States)

    Bruss, Matthew D; Khambatta, Cyrus F; Ruby, Maxwell A; Aggarwal, Ishita; Hellerstein, Marc K

    2010-01-01

    Calorie restriction (CR) increases longevity and retards the development of many chronic diseases, but the underlying metabolic signals are poorly understood. Increased fatty acid (FA) oxidation and reduced FA synthesis have been hypothesized to be important metabolic adaptations to CR. However, at metabolic steady state, FA oxidation must match FA intake plus synthesis; moreover, FA intake is low, not high, during CR. Therefore, it is not clear how FA dynamics are altered during CR. Accordingly, we measured food intake patterns, whole body fuel selection, endogenous FA synthesis, and gene expression in mice on CR. Within 2 days of CR being started, a shift to a cyclic, diurnal pattern of whole body FA metabolism occurred, with an initial phase of elevated endogenous FA synthesis [respiratory exchange ratio (RER) >1.10, lasting 4-6 h after food provision], followed by a prolonged phase of FA oxidation (RER = 0.70, lasting 18-20 h). CR mice oxidized four times as much fat per day as ad libitum (AL)-fed controls (367 +/- 19 vs. 97 +/- 14 mg/day, P intake from fat. This increase in FA oxidation was balanced by a threefold increase in adipose tissue FA synthesis compared with AL. Expression of FA synthase and acetyl-CoA carboxylase mRNA were increased in adipose and liver in a time-dependent manner. We conclude that CR induces a surprising metabolic pattern characterized by periods of elevated FA synthesis alternating with periods of FA oxidation disproportionate to dietary FA intake. This pattern may have implications for oxidative damage and disease risk. PMID:19887594

  5. Silica Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Quinoxalines at Room Temperature

    Directory of Open Access Journals (Sweden)

    Khodabakhsh Niknam

    2009-05-01

    Full Text Available The reaction of 3-mercaptopropylsilica (MPS and chlorosulfonic acid in chloroform afforded silica bonded S-sulfonic acid (SBSSA, which was used as a catalyst for the room temperature synthesis of quinoxaline derivatives from 1,2-diamino compounds and 1,2-dicarbonyl compounds. The catalyst could be recycled and reused several times without any loss of efficiency.

  6. Glycerine and levulinic acid: renewable co-substrates for the fermentative synthesis of short-chain poly(hydroxyalkanoate) biopolymers

    Science.gov (United States)

    Glycerine and levulinic acid were used alone and in combination for the fermentative synthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/V) biopolymers. Shake-flask cultures of Pseudomonas oleovorans NRRL B-14682 containing different glycerine:levulinic acid ratios (1%, w/v total carbon ...

  7. Asymmetric synthesis of allylic sulfonic acids: enantio- and regioselective iridium-catalyzed allylations of Na2SO3.

    Science.gov (United States)

    Liu, Wei; Zhao, Xiao-ming; Zhang, Hong-bo; Zhang, Liang; Zhao, Ming-zhu

    2014-12-15

    An enantioselective allylation reaction of allylic carbonates with sodium sulfite (Na2 SO3 ) catalyzed by Ir complex was accomplished, providing allylic sulfonic acids in good to excellent yields with a high level of enantio- and regioselectivities. (R)-2-Phenyl-2-sulfoacetic acid, a key intermediate for the synthesis of Cefsulodin and Sulbenicillin, was synthesized as well. PMID:25367779

  8. SYNTHESIS AND CHARACTERIZATION OF A NOVEL SOLID ACID CATALYST FOR IMPROVED USE OF WASTE OIL FEEDSTOCK FOR BIODIESEL PRODUCTION

    Science.gov (United States)

    Carbon Catalyst Synthesis - Sucrose was treated directly with excess sulfuric acid sulfuric acid (9:1 mol/mol, 25°C). A carbon foam (nearly 20 fold increase in bulk volume) was immediately formed. The foam was then washed until no sulfate was dete...

  9. The Synthesis of a Dipeptide from its Component Amino Acids: Protecting Groups in the Elementary Organic Laboratory.

    Science.gov (United States)

    Young, Paul E.; Campbell, Andrew

    1982-01-01

    A simple, three-step procedure for synthesizing a dipeptide from its component amino acids is described. The dipeptide synthesized uses inexpensive amino acids having hydrocarbon side-chains and can be observed in E/Z forms by nuclear magnetic resonance spectroscopy. Each step in the synthesis produces white crystalline products using standard…

  10. Synthesis of optically active dodecaborate-containing L-amino acids for BNCT

    International Nuclear Information System (INIS)

    A convenient and simple synthetic method of dodecaboratethio-L-amino acid, a new class of tumor-seeking boron carrier for BNCT, was accomplished from S-cyanoethylthioundecahydro-closo-dodecaborate (S-cyanoethyl-10BSH, [10B12H11]2?SCH2CH2CN) and bromo-L-?-amino acids by nearly one step S-alkylation. An improved synthesis of S-cyanoethyl-10BSH, a key starting compound for S-alkylation, was also performed by Michael addition of 10BSH with acryronitrile in high yield. Four kinds of new dodecaboratethio-L-amino acids were obtained in optically pure form without the need for any optical resolution.

  11. Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway.

    Science.gov (United States)

    Lovelock, Sarah L; Lloyd, Richard C; Turner, Nicholas J

    2014-04-25

    Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1 cB elimination mechanism. PMID:24692092

  12. Parallel Synthesis of an Imidazole-4,5-dicarboxamide Library Bearing Amino Acid Esters and Alkanamines

    Directory of Open Access Journals (Sweden)

    Rosanna Solinas

    2008-12-01

    Full Text Available The imidazole-4,5-dicarboxylic acid scaffold is readily derivatized with amino acid esters and alkanamines to afford compounds with intramolecularly hydrogen bonded conformations that mimic substituted purines and therefore are hypothesized to be potential inhibitors of kinases through competitive binding to the ATP site. In this work, a total of 126 dissymmetrically disubstituted imidazole-4,5-dicarboxamides with amino acid ester and alkanamide substituents were prepared by parallel synthesis. The library members were purified by column chromatography on silica gel and the purified compounds characterized by LC-MS with LC detection at 214 nm. A selection of the final compounds was also analyzed by 1H-NMR spectroscopy. The analytically pure final products have been submitted to the Molecular Library Small Molecule Repository (MLSMR for screening in the Molecular Library Screening Center Network (MLSCN as part of the NIH Roadmap.

  13. Poly(aniline-co--aminobenzoic acid) deposited on poly(vinyl alcohol): Synthesis and characterization

    Indian Academy of Sciences (India)

    S Adhikari; P Banerji

    2013-08-01

    In this work, we have deposited poly(aniline-co--aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ polymerization. The polymerization was effected within maleic acid (MA) cross-linked PVA hydrogel. The copolymer was obtained by oxidative polymerization of aniline hydrochloride and -aminobenzoic acid using ammonium persulfate as an oxidant. Instead of conventional solution polymerization, here synthesis was carried out on APS soaked MA cross-linked PVA (MA–PVA) film where the polymer was in situ deposited in its conducting form. The composite film was characterized by Fourier transform infra red (FT–IR) and ultraviolet visible (UV–VIS) spectroscopy and electrical measurements. Surface morphology of the composite films was studied by field emission scanning electron microscopy (FESEM). The variation of conductivity of the films was studied.

  14. Total synthesis and properties of the crambescidin core zwitterionic acid and crambescidin 359.

    Science.gov (United States)

    Aron, Zachary D; Overman, Larry E

    2005-03-16

    The total synthesis of the crambescidin core acid 9, crambescidins 359 (8) and 431 (7), and the properties of the crambescidin core are described. A key step of the synthetic route to guanidinium carboxylate 9 is Pd(0) catalyzed cleavage of the ester side chain of pentacyclic cinnamyl ester 15. This ester is also employed to prepare a small library of crambescidin alkaloid analogues that differ in their C14 side chain. The zwitterionic guanidinium carboxylate 9 was shown to readily decarboxylate to form crambescidin 359 (8). Decarboxylation of crambescidin core acid 9 was fastest under basic conditions. In the presence of base, up to eight deuterium atoms can be incorporated into the pentacyclic crambescidin core. Both deuterium incorporation and decarboxylation of crambescidin core acid 9 are the result of facile ring opening of the spirocyclic ether rings of the pentacyclic guanidinium moiety. PMID:15755156

  15. Radiation synthesis of hydrogels with diprotic acid moieties and their use in the adsorption of biomolecules

    CERN Document Server

    Sen, M

    1996-01-01

    Radiation synthesis of diprotic acid moieties containing poly (N-vinyl 2- pyrrolidone) and polyacrylamide hydrogels and their use in the adsorption of biomolecules such as enzymes, proteins and drugs have been investigated. Hydrogels with varying cross-linked densities and ionic moieties were prepared from the ternary systems of N-vinyl 2-pyrrolidone/itaconic acid/water and acrylamide/maleic acid/water by irradiating with gamma rays at ambient temperature. For the characterization of network structure of hydrogels new equations were derived. Determination of average molecular weight between cross-links of hydrogels sensitive to pH changes of the swelling medium was investigated. In order to explain the influence of other external stimuli such as temperature and ionic strength of the swelling medium and the type of the buffer solution on the equilibrium swelling properties were investigated. The effect of these external stimuli on the biomolecule adsorption capacity of hydrogels were investigated for bovine se...

  16. Synthesis of optically active dodecaborate-containing L-amino acids for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Kusaka, Shintaro [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai (Japan); Hattori, Yoshihide, E-mail: y0shi_hattori@riast.osakafu-u.ac.jp [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai (Japan); Uehara, Kouki; Asano, Tomoyuki [Stella Pharma Corporation, ORIX Kouraibashi Bldg. 5F 3-2-7 Kouraibashi, Chuo-ku, Osaka (Japan); Tanimori, Shinji; Kirihata, Mitsunori [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai (Japan)

    2011-12-15

    A convenient and simple synthetic method of dodecaboratethio-L-amino acid, a new class of tumor-seeking boron carrier for BNCT, was accomplished from S-cyanoethylthioundecahydro-closo-dodecaborate (S-cyanoethyl-{sup 10}BSH, [{sup 10}B{sub 12}H{sub 11}]{sup 2-}SCH{sub 2}CH{sub 2}CN) and bromo-L-{alpha}-amino acids by nearly one step S-alkylation. An improved synthesis of S-cyanoethyl-{sup 10}BSH, a key starting compound for S-alkylation, was also performed by Michael addition of {sup 10}BSH with acryronitrile in high yield. Four kinds of new dodecaboratethio-L-amino acids were obtained in optically pure form without the need for any optical resolution.

  17. Monoestolides Synthesis From Ricinoleic-Oleic Acids Using Silicotungstic Acid Sol-Gel Catalyst

    Directory of Open Access Journals (Sweden)

    Nor Asikin Mohamad Nordin

    2011-09-01

    Full Text Available Sol-gel silica-supported hydrated silicotungstic acid (STA sol-gel, prepared by incorporating hydrated silicotungstic acid (STA into silica via sol-gel technique, was used as an efficient heterogeneous catalyst for condensation reaction of a mixture ricinoleic acid (RA and oleic acid (OA. The activity and selectivity of STA sol-gel for the condensation reaction of a mixture RA and OA have been investigated and compared with unsupported STA and homogeneous perchloric acid. STA sol-gel and bulk STA catalysts surface were characterized using X-ray Photoelectron Spectroscopy (XPS analysis. The reactions were carried out under vacuum (2 mBar for 10 hours at 70 0C under solvent-less conditions. The Liquid Chromatography-Mass Spectrometry (LC-MS of reaction products results showed chromatographic peaks for the presence of three new monoestolides at retention times (tR 9.2 min (m/z 577.48, as [M-H]-, 11.2 min (m/z 559.46, [M-H]- and 12.6 min (m/z 561.48, [M-H]-. STA sol-gel catalyst is new promising heterogenous catalyst that can be used for producing estolide compounds from a mixture of RA and OA. STA sol-gel gave 100 % conversion with 60.62 % selectivity to ricinoleic-ricinoleic monoestolide acid (m/z 577.48, [M-H]-, 25.69 % selectivity to ricinoleic-linoleic monoestolide acid (m/z 559.47, [M-H]- and 13.65 % selectivity to ricinoleic-oleic monoestolide (m/z 561.48, [M-H]-.

  18. Epoxy Resin and Polyurethane Compositions from Glycolized Poly (ethylene terephthalate Wastes

    Directory of Open Access Journals (Sweden)

    Gintaras MACIJAUSKAS

    2013-09-01

    Full Text Available The possibility to use poly(ethylene terephthalate (PET bottles production waste as raw material for compositions with high adhesion ability has been investigated. PET waste was glycolyzed with polypropylene glycol and three kinds of oligoesters were formed after depolymerization reaction. The polydispersity of product formed was 1.05. The possibilities to use PET glycolysis products – oligoesters for epoxy resin and polyurethanes were studied. Two-step reaction of oligoesters with epichlorohydrin was chosen for epoxy resin synthesis, while glycolyzed PET reaction with aliphatic isocyanate was used for polyurethane synthesis. The structure and properties of the obtained polymers were investigated. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5237

  19. Chemoenzymatic synthesis of immunogenic meningococcal group C polysialic acid-tetanus Hc fragment glycoconjugates.

    Science.gov (United States)

    McCarthy, Pumtiwitt C; Saksena, Rina; Peterson, Dwight C; Lee, Che-Hung; An, Yanming; Cipollo, John F; Vann, Willie F

    2013-12-01

    Vaccination with meningococcal glycoconjugate vaccines has decreased the incidence of invasive meningitis worldwide. These vaccines contain purified capsular polysaccharides attached to a carrier protein. Because of derivatization chemistries used in the process, conjugation of polysaccharide to protein often results in heterogeneous mixtures. Well-defined vaccines are needed to determine the relationship between vaccine structure and generated immune response. Here, we describe efforts to produce well-defined vaccine candidates by chemoenzymatic synthesis. Chemically synthesized lactosides were substrates for recombinant sialyltransferase enzymes from Camplyobacter jejuni and Neisseria meningitidis serogroup C. These resulting oligosialic acids have the same ?(2-9) sialic acid repeat structure as Neisseria polysaccharide capsule with the addition of a conjugatable azide aglycon. The degree of polymerization (DP) of carbohydrate products was controlled by inclusion of the inhibitor CMP-9-deoxy-NeuNAc. Polymers with estimated DP tetanus toxin protein (TetHc) was coupled as a carrier to the enzymatically synthesized oligosialic acids. Recombinant TetHc was derivatized with an alkyne squarate. Protein modification sites were determined by trypsin proteolysis followed by LC/MS-MS(E) analysis of peptides. Oligosialic acid azides were conjugated to modified TetHc via click chemistry. These chemoenzymatically prepared glycoconjugates were reactive in immunoassays with specific antibodies against either group C polysaccharide or TetHc. Sera of mice immunized with oligosialic acid-TetHc glycoconjugates contained much greater levels of polysaccharide-reactive IgG than the sera of control mice receiving unconjugated oligosialic acids. There was no apparent difference between glycoconjugates containing oligosaccharides of DP synthesis may provide a viable method for making defined meningococcal vaccine candidates. PMID:23949787

  20. Isoniazid inhibition of mycolic acid synthesis by cell extracts of sensitive and resistant strains of Mycobacterium aurum.

    OpenAIRE

    Quémard, A; Lacave, C; Lanéelle, G

    1991-01-01

    Isonicotinic acid hydrazide (isoniazid; INH) inhibition of mycolic acid synthesis was studied by using cell extracts from both INH-sensitive and -resistant strains of Mycobacterium aurum. The cell extract of the INH-sensitive strain was inhibited by INH, while the preparation from the INH-resistant strain was not. This showed that the INH resistance of mycolic acid synthesis was not due to a difference in drug uptake or the level of peroxidase activity (similar in both extracts). As INH did n...

  1. One-Pot Synthesis of Novel Chiral ?-Amino Acid Derivatives by Enantioselective Mannich Reactions Catalyzed by Squaramide Cinchona Alkaloids

    Directory of Open Access Journals (Sweden)

    Kankan Zhang

    2013-05-01

    Full Text Available An ef?cient one-pot synthesis of novel ?-amino acid derivatives containing a thiadiazole moiety was developed using a chiral squaramide cinchona alkaloid as organocatalyst. The reactions afforded chiral ?-amino acid derivatives in moderate yields and with moderate to excellent enantioselectivities. The present study demonstrated for the first time the use of a Mannich reaction catalyzed by a chiral bifunctional organocatalyst for the one-pot synthesis of novel ?-amino acid derivatives bearing a 1,3,4-thiadiazole moiety on nitrogen.

  2. Amino acids attached to 2'-amino-LNA: Synthesis of DNA mixmer oligonucleotides with increased duplex stability

    DEFF Research Database (Denmark)

    Johannsen, Marie Willaing; Wengel, Jesper

    The synthesis of 2'-amino-LNA (locked nucleic acid) opens up exciting possibilities for modification of nucleic acids by conjugation to the 2'-nitrogen. Incorporation of unmodified and N-functionalized 2'-amino-LNA nucleotides improve duplex stability compared to unmodified DNA. 2'-Amino-LNA nucleosides derivatized with amino acids have been synthesized and incorporated into DNA oligonucleotides. Following oligonucleotide synthesis, peptides have been added using solid phase peptide coupling chem. Modification of oligonucleotides with pos. charged residues greatly improves thermal stability.

  3. Amplification by (-)-epigallocatechin gallate and chlorogenic acid of TNF-?-stimulated interleukin-6 synthesis in osteoblasts.

    Science.gov (United States)

    Yamamoto, Naohiro; Tokuda, Haruhiko; Kuroyanagi, Gen; Kainuma, Shingo; Ohguchi, Reou; Fujita, Kazuhiko; Matsushima-Nishiwaki, Rie; Kozawa, Osamu; Otsuka, Takanobu

    2015-12-01

    Polyphenolic compounds in foods and beverages have beneficial effects on human health. (-)-Epigallocatechin gallate (EGCG) and chlorogenic acid (CGA), a major flavonoid in green tea and a major phenolic acid in coffee, respectively, have potent properties, including antioxidative effects. Our previous study demonstrated that p70 S6 kinase acts as a negative regulator in tumor necrosis factor-? (TNF-?)-stimulated interleukin-6 synthesis in osteoblast-like MC3T3-E1 cells. In the present study, the effects of EGCG and CGA on the TNF???stimulated interleukin?6 synthesis were investigated in MC3T3?E1 cells. EGCG and CGA significantly enhanced TNF???stimulated interleukin?6 release. In addition, the interleukin?6 mRNA expression levels induced by TNF?? were supported by EGCG, as well as CGA. EGCG markedly attenuated the TNF-?-induced phosphorylation of p70 S6 kinase whereas CGA failed to affect the phosphorylation. These results strongly suggest that EGCG and CGA enhance the TNF???stimulated interleukin-6 synthesis in osteoblasts, and that the amplifying effect of EGCG, but not CGA, is exerted via inhibiting p70 S6 kinase. PMID:26496857

  4. Effects on cell growth processes (mitosis, synthesis of nucleic acids and of proteins). Chapter 7

    International Nuclear Information System (INIS)

    A review is presented of reports of the interference of -SH radioprotective agents with cell division and with the processes of nucleic acid and protein synthesis which are a prerequisite for mitosis. Mitotic activity is inhibited to the same extent in mammalian tissues as in cultures of animal and plant cells and bacteria. With cultured cells, the toxicity and the antimitotic activity have been found to be at their highest level for intermediate concentrations of the compound and to decrease for higher and lower concentrations. Inhibition of the synthesis of nucleic acids by -SH radioprotective substances has been observed with cultures of cells and bacteria and in mammalian tissues. In vitro interactions with the structures of free DNA and nucleoprotein have also been studied. The extent to which such complexes between the protective agent and DNA or nucleoprotein occur in vivo is not known. A depression of protein synthesis has been observed, and participates in the more general inhibition of growth processes. Possible mechanisms of these effects are discussed. (U.K.)

  5. Asymmetric synthesis of syn-propargylamines and unsaturated ?-amino acids under Brønsted base catalysis.

    Science.gov (United States)

    Wang, Yingcheng; Mo, Mingjie; Zhu, Kongxi; Zheng, Chao; Zhang, Hongbin; Wang, Wei; Shao, Zhihui

    2015-01-01

    Propargylamines are important intermediates for the synthesis of polyfunctional amino derivatives and natural products and biologically active compounds. The classic method of synthesizing chiral propargylamines involves the asymmetric alkynylation of imines. Here, we report a significant advance in the catalytic asymmetric Mannich-type synthesis of propargylamines through catalytic asymmetric addition of carbon nucleophiles to C-alkynyl imines, culminating in a highly syn-selective catalytic asymmetric Mannich reaction of C-alkynyl imines that provide syn-configured propargylamines with two adjacent stereogenic centres and a transition metal-free organocatalytic asymmetric approach to ?-alkynyl-?-amino acids with high efficiency and practicality, via a chiral Brønsted base-catalysed asymmetric Mannich-type reaction of in situ generated challenging N-Boc C-alkynyl imines from previously unreported C-alkynyl N-Boc-N,O-acetals, with ?-substituted ?-keto esters and less-acidic malonate (thio)esters as nucleophiles, respectively. A catalytic activation strategy is also disclosed, which may have broad implications for use in catalysis and synthesis. PMID:26423837

  6. Synthesis and optimization ring opening of monoepoxide linoleic acid using p-toluenesulfonic acid.

    Science.gov (United States)

    Salimon, Jumat; Abdullah, Bashar Mudhaffar; Yusop, Rahimi M; Salih, Nadia; Yousif, Emad

    2013-01-01

    Biolubricant base oils, 9,12-hydroxy-10,13-oleioxy-12-octadecanoic acid (HYOOA) was synthesized based on the esterification reaction of Monoepoxide linoleic acid 9(12)-10(13)-monoepoxy 12(9)-octadecanoic acid (MEOA) with oleic acid (OA) and catalyzed by p-Toluenesulfonic acid. The optimum conditions for the experiment using D-optimal design to obtain high yield% of 84.61, conversion% of 83.54 and lowest OOC% of 0.05 were predicted at OA/MEOA ratio of 0.2:1 (mol/mol), PTSA/MEOA ratio of 0.4:1 (mol/mol), reaction temperature at 110°C, and reaction time at 4.5 h. The FTIR peaks of HYOOA indicate the disappearance of the absorption band at 820 cm(-1), which belongs to the oxirane ring. (13)C and (1)H NMR spectra analyses confirmed the result of HYOOA with appearance carbon-ester (C?=?O) chemical shift at 174.1 ppm and at 4.06 ppm for (13)C and (1)H NMR respectively. PMID:24083099

  7. 76 FR 12937 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for Final...

    Science.gov (United States)

    2011-03-09

    ...Administration [A-533-824] Polyethylene Terephthalate Film, Sheet and Strip...antidumping duty order on polyethylene terephthalate film, sheet and strip...December 31, 2009. See Polyethylene Terephthalate Film, Sheet and...

  8. 76 FR 12938 - Polyethylene Terephthalate Film, Sheet and Strip From India: Extension of Time Limit for Final...

    Science.gov (United States)

    2011-03-09

    ...Administration [C-533-825] Polyethylene Terephthalate Film, Sheet and Strip...countervailing duty order on polyethylene terephthalate film, sheet and strip...December 31, 2009. See Polyethylene Terephthalate Film, Sheet, and...

  9. 78 FR 52500 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Notice of...

    Science.gov (United States)

    2013-08-23

    ...Administration [A-570-924] Polyethylene Terephthalate Film, Sheet, and Strip...2\\ See Polyethylene Terephthalate Film, Sheet, and Strip...Int'l Trade 2013); Polyethylene Terephthalate Film, Sheet, and...

  10. 78 FR 14266 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Notice of Correction to the Final...

    Science.gov (United States)

    2013-03-05

    ...Administration [A-583-837] Polyethylene Terephthalate Film, Sheet, and Strip...antidumping duty order on polyethylene terephthalate film, sheet, and strip...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  11. 76 FR 22867 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates: Final Results of...

    Science.gov (United States)

    2011-04-25

    ...Trade Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...following events have taken place. See Polyethylene Terephthalate Film, Sheet, and...

  12. 76 FR 1135 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2011-01-07

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip...review of the antidumping duty order on polyethylene terephthalate film, sheet, and...

  13. 77 FR 20357 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates: Final Results of...

    Science.gov (United States)

    2012-04-04

    ...Trade Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  14. 75 FR 70901 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2010-11-19

    ...Trade Administration [A-580-807] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping order on polyethylene terephthalate film, sheet and strip...the Republic of Korea (Korea). See Polyethylene Terephthalate Film, Sheet, and...

  15. 78 FR 29700 - Polyethylene Terephthalate Film, Sheet, and Strip From the United Arab Emirates: Final Results of...

    Science.gov (United States)

    2013-05-21

    ...Trade Administration [A-520-803] Polyethylene Terephthalate Film, Sheet, and Strip...review of the antidumping duty order on polyethylene terephthalate film (PET Film) from...1\\ See Polyethylene Terephthalate Film, Sheet, and...

  16. S-(?-10,11-Dihydroxyfarnesoic Acid Methyl Ester Inhibits Melanin Synthesis in Murine Melanocyte Cells

    Directory of Open Access Journals (Sweden)

    Seung-Hwa Baek

    2014-07-01

    Full Text Available The development of antimelanogenic agents is important for the prevention of serious aesthetic problems such as melasmas, freckles, age spots, and chloasmas. In the course of screening for melanin synthesis inhibitors, we found that the culture broth from an insect morphopathogenic fungus, Beauveria bassiana CS1029, exhibits potent antimelanogenic activity. We isolated and purified an active metabolite and identified it as S-(?-10,11-dihydroxyfarnesoic acid methyl ester (dhFAME, an insect juvenile hormone. To address whether dhFAME inhibits melanin synthesis, we first measured the size of the melanin biosynthesis inhibition zone caused by dhFAME. dhFAME also showed inhibitory activity against mushroom tyrosinase in Melan-a cells. Intracellular, dose-dependent tyrosinase inhibition activity was also confirmed by zymography. In addition, we showed that dhFAME strongly inhibits melanin synthesis in Melan-a cells. Furthermore, we compared levels of TYR, TRP-1, TRP-2, MITF, and MC1R mRNA expression by reverse-transcription polymerase chain reaction and showed that treatment of Melan-a cells with 35 ?M dhFAME led to an 11-fold decrease in TYR expression, a 6-fold decrease in TRP-2 expression, and a 5-fold decrease in MITF expression. Together, these results indicate that dhFAME is a potent inhibitor of melanin synthesis that can potentially be used for cosmetic biomaterial(s.

  17. Ammonia lyases and aminomutases as biocatalysts for the synthesis of ?-amino and ?-amino acids.

    Science.gov (United States)

    Turner, Nicholas J

    2011-04-01

    Ammonia lyases catalyse the reversible addition of ammonia to cinnamic acid (1: R=H) and p-hydroxycinnamic (1: R=OH) to generate L-phenylalanine (2: R=H) and L-tyrosine (2: R=OH) respectively (Figure 1a). Both phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) are widely distributed in plants, fungi and prokaryotes. Recently there has been interest in the use of these enzymes for the synthesis of a broader range of L-arylalanines. Aminomutases catalyse a related reaction, namely the interconversion of ?-amino acids to ?-amino acids (Figure 1b). In the case of L-phenylalanine, this reaction is catalysed by phenylalanine aminomutase (PAM) and proceeds stereospecifically via the intermediate cinnamic acid to generate ?-Phe 3. Ammonia lyases and aminomutases are related in sequence and structure and share the same active site cofactor 4-methylideneimidazole-5-one (MIO). There is currently interest in the possibility of using these biocatalysts to prepare a wide range of enantiomerically pure l-configured ?-amino and ?-amino acids. Recent reviews have focused on the mechanism of these MIO containing enzymes. The aim of this review is to review recent progress in the application of ammonia lyase and aminomutase enzymes to prepare enantiomerically pure ?-amino and ?-amino acids. PMID:21131229

  18. Effect of penicillin on fatty acid synthesis and excretion in Streptococcus mutans BHT

    Energy Technology Data Exchange (ETDEWEB)

    Brissette, J.L.; Pieringer, R.A.

    1985-03-01

    Treatment of exponentially growing cultures of Streptococcus mutans BHT with growth-inhibitory concentrations (0.2 microgram/ml) of benzylpenicillin stimulates the incorporation of (2-/sup 14/C) acetate into lipids excreted by the cells by as much as 69-fold, but does not change the amount of /sup 14/C incorporated into intracellular lipids. At this concentration of penicillin cellular lysis does not occur. The radioactive label is incorporated exclusively into the fatty acid moieties of the glycerolipids. During a 4-hr incubation in the presence of penicillin, the extracellular fatty acid ester concentration increases 1.5 fold, even though there is no growth or cellular lysis. An indication of the relative rate of fatty acid synthesis was most readily obtained by placing S. mutans BHT in a buffer containing /sup 14/C-acetate. Under these nongrowing conditions free fatty acids are the only lipids labeled, a factor which simplifies the assay. The addition of glycerol to the buffer causes all of the nonesterified fatty acids to be incorporated into glycerolipid. The cells excrete much of the lipid whether glycerol is present or not. Addition of penicillin to the nongrowth supporting buffer system does not stimulate the incorporation of (/sup 14/C)-acetate into fatty acids.

  19. Chemical modification and functionalisation of poly(ethylene terephthalate) fiber

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.H.; Kim, S.H. [Sungkyunkwan University, Suwon (Korea)

    2002-05-01

    Poly(ethylene terephthalate ) (PET) fibers were modified by deep UV irradiation which was produced by a low pressure mercury lamp. FT-IR and XPS analyses were used to elucidate the surface chemical composition of PET fibers treated with UV. Relative O{sub 1s} intensity increased considerably and it was found that oxygen was incorporated in the form of COO on the fiber surface. FT-IR and XPS analyses proved the existence of carboxylic groups on the surfaces and the adsorption test of cationic compound further supported these results. The concentration of carboxylic acid group on the surface increased remarkably with increasing irradiation time. XPS analysis and adsorption experiments proved that the surface structure of the UV{sub i}rradiated PET fibers were stable for 12 months. Antibacterial property and the deodorization rate of UV-irradiated PET fibers adsorbed with the berberine compound were investigated. reduction rates of bacteria increased by about 21 to 99% compared to unradiated PET fiber. Deodorization rates of 23% for unradiated PET fiber increased to about 75% for 30 min irradiated samples. (author). 33 refs., 3 tabs., 11 figs.

  20. Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media

    OpenAIRE

    Moret, Séverine; Paul J. Dyson; Laurenczy, Gábor

    2014-01-01

    The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40?°C, 0.2?M formic acid can be obtained under 200?bar, however, in DMSO the same catalyst affords 1.9?M...