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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. Renal handling of terephthalic acid

    International Nuclear Information System (INIS)

    By use of the Sperber in vivo chicken preparation method, infusion of radiolabeled terephthalic acid ([14C]TPA) into the renal portal circulation revealed a first-pass excretion of the unchanged compound into the urine. This model was utilized further to characterize the excretory transport of [14C]TPA and provide information on the structural specificity in the secretion of dicarboxylic acids. At an infusion rate of 0.4 nmol/min. 60% of the [14C]TPA which reached the kidney was directly excreted. An infusion rate of 3 or 6 mumol/min resulted in complete removal of [14C]TPA by the kidney. These results indicate that TPA is both actively secreted and actively reabsorbed when infused at 0.4 nmol/min and that active reabsorption is saturated with the infusion of TPA at higher concentrations. The secretory process was saturated with the infusion of TPA at 40 mumol/mn. The excretory transport of TPA was inhibited by the infusion of probenecid, salicylate, and m-hydroxybenzoic acid, indicating that these organic acids share the same organic anion excretory transport process. m-Hydroxybenzoic acid did not alter the simultaneously measured excretory transport of p-aminohippuric acid (PAH), suggesting that there are different systems involved in the secretion of TPA and PAH. The structural specificity for renal secretion of dicarboxylic acids was revealed by the use of o-phthalic acid and m-phthalic acid as possible inhibitors of TPA secretion

  5. Electrochemical synthesis of FeS2 thin film: An effective material for peroxide sensing and terephthalic acid degradation

    International Nuclear Information System (INIS)

    Electrochemically FeS2 thin films have been synthesized on ITO substrates at room temperature (25 °C). UV–Vis, X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) were used for the characterization of nanostructure FeS2 thin films. Two probe I–V measurements convey that the material is p type and a p-n junction (diode) was found to be developed between FeS2 and ITO layer. Cyclic voltametry study shows that FeS2/ITO electrode facilitates the reduction of hydrogen peroxide and exhibits excellent electro-catalytic activity towards its sensing. Photocatalytic study reveals that the synthesized thin films are also efficient to degrade terephthalic acid (TA). - Graphical abstract: Electrochemically FeS2 thin films have been synthesized on ITO substrate. The synthesized material is effective for the reduction of H2O2 and the sensitivity of the material is strongly dependent on pH and temperature. Photocatalytic study reveals that the material is quite effective towards decomposition of terephthalic acid. These results indicate that the material can play a dual role as pollutant cleanup for environmental interest. - Highlights: • Electrochemically FeS2 thin films are synthesized. • The material is effective to sense the H2O2 and degrade terephthalic acid. • It plays a dual role as pollutant cleanup for environmental interest

  6. 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

  7. Solvothermal synthesis of uranium(VI) phases with aromatic carboxylate ligands: A dinuclear complex with 4-hydroxybenzoic acid and a 3D framework with terephthalic acid

    Science.gov (United States)

    Zhang, Yingjie; Karatchevtseva, Inna; Bhadbhade, Mohan; Tran, Toan Trong; Aharonovich, Igor; Fanna, Daniel J.; Shepherd, Nicholas D.; Lu, Kim; Li, Feng; Lumpkin, Gregory R.

    2016-02-01

    With the coordination of dimethylformamide (DMF), two new uranium(VI) complexes with either 4-hydroxybenzoic acid (H2phb) or terephthalic acid (H2tph) have been synthesized under solvothermal conditions and structurally characterized. [(UO2)2(Hphb)2(phb)(DMF)(H2O)3]·4H2O (1) has a dinuclear structure constructed with both pentagonal and hexagonal bipyramidal uranium polyhedra linked through a ?2-bridging ligand via both chelating carboxylate arm and alcohol oxygen bonding, first observation of such a coordination mode of 4-hydroxybenzoate for 5 f ions. [(UO2)(tph)(DMF)] (2) has a three-dimensional (3D) framework built with pentagonal bipyramidal uranium polyhedra linked with ?4-terephthalate ligands. The 3D channeled structure is facilitated by the unique carboxylate bonding with nearly linear C-O-U angles and the coordination of DMF molecules. The presence of phb ligands in different coordination modes, uranyl ions in diverse environments and DMF in complex 1, and tph ligand, DMF and uranyl ion in complex 2 has been confirmed by Raman spectroscopy. In addition, their thermal stability and photoluminescence properties have been investigated.

  8. Kinetic and Catalytic Studies in Polyethylene Terephthalate Synthesis

    OpenAIRE

    Ahmadnian, Fatemeh

    2008-01-01

    Polyethylene terephthalate synthesis by polycondensation of bis (hydroxyethylene) terephthalate and its low molecular weight oligomers catalyzed by different titanium (IV) based catalysts was investigated. An industrial catalyst, antimony triacetate, was used as a reference catalyst. Polycondensation was carried out in a stirred tank reactor made of aluminium in the temperature range of 250°C to 280°C under 1 mbar vacuum. The products were characterized with respect to conversion of reaction,...

  9. Production of Diethyl Terephthalate from Biomass-Derived Muconic Acid.

    Science.gov (United States)

    Lu, Rui; Lu, Fang; Chen, Jiazhi; Yu, Weiqiang; Huang, Qianqian; Zhang, Junjie; Xu, Jie

    2016-01-01

    We report a cascade synthetic route to directly obtain diethyl terephthalate, a replacement for terephthalic acid, from biomass-derived muconic acid, ethanol, and ethylene. The process involves two steps: First, a substituted cyclohexene system is built through esterification and Diels-Alder reaction; then, a dehydrogenation reaction provides diethyl terephthalate. The key esterification reaction leads to improved solubility and modulates the electronic properties of muconic acid, thus promoting the Diels-Alder reaction with ethylene. With silicotungstic acid as the catalyst, nearly 100 % conversion of muconic acid was achieved, and the cycloadducts were formed with more than 99.0 % selectivity. The palladium-catalyzed dehydrogenation reaction preferentially occurs under neutral or mildly basic conditions. The total yield of diethyl terephthalate reached 80.6 % based on the amount of muconic acid used in the two-step synthetic process. PMID:26592149

  10. 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.

  11. 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 ...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Transient Current Behaviour of Poly (p-hydroxybenzoic acid-co-ethylene terephthalate) Liquid Crystal Polymers

    Science.gov (United States)

    Yarramaneni, Sridharbabu; Sharma, Anu; Quamara, J. K.

    2011-07-01

    Transient current behaviour of pristine Poly (p-hydroxybenzoic acid-co-ethylene terephthalate) Liquid crystal polymer which is a copolymer of poly ethylene terephthalate and poly p-hydroxybenzoic acid referred as PET/x.PHB polymer liquid crystals have been studied at different biasing electric fields ranging from 13 kV/cm to 104.3 kV/cm and at temperatures 120° C and 250° C for molar ratio x =0.8.

  17. 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.

  18. 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

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

    OpenAIRE

    Smitha Rajesh; Zagabathuni Venkata Panchakshari Murthy

    2014-01-01

    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 expensive, 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 scien...

  20. 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...

  1. 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.

  2. Rapid determination of terephthalic acid in the hydrothermal decomposition product of poly(ethylene terephthalate) by thermochemolysis-gas chromatography in the presence of tetramethylammonium acetate.

    Science.gov (United States)

    Ishida, Yasuyuki; Ohsugi, Kei; Taniguchi, Kohei; Ohtani, Hajime

    2011-01-01

    Thermochemolysis-gas chromatography in the presence of tetramethylammonium acetate was applied to the direct determination of terephthalic acid (TPA) contained in solid decomposition products obtained from the hydrothermal recycling process of poly(ethylene terephthalate) (PET). On the chromatograms of the hydrothermal decomposition products of PET, a sharp peak of the TPA component was clearly observed as its corresponding dimethyl ester formed through the thermochemolysis reaction. Based on the peak intensities, the contents of TPA in the decomposition products were determined precisely and rapidly without using any cumbersome sample pretreatments. PMID:21985932

  3. 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.

  4. 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)

  5. 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.

  6. 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)

  7. 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)

  8. 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

  9. 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.

  10. 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

  11. 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

  12. ?-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)

  13. 4-[(E-2-(Pyridin-2-ylethenyl]pyridine–terephthalic acid (2/1

    Directory of Open Access Journals (Sweden)

    Paola Castro-Montes

    2012-12-01

    Full Text Available The title 2:1 co-crystal, 2C12H10N2·C8H6O4, crystallizes with one molecule of 4-[(E-2-(pyridin-2-ylethenyl]pyridine (A and one half-molecule of terephthalic acid (B in the asymmetric unit. In the crystal, the components are linked through heterodimeric COOH...Npyridine synthons, forming linear aggregates of composition –A–B–A–B–. Further linkage through weak C—H...O and C—H...? interactions gives two-dimensional hydrogen-bonded undulating sheets propagating in the [100] and [010] directions. These layers are connected through additional weak C—H...O contacts, forming a three-dimensional structure.

  14. 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)

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Smitha Rajesh

    2014-01-01

    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 expensive, 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.

  17. 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...

  18. The effect of oligomeric terminal group balance on catalyzed polycondensation of Poly(ethylene terephthalate)

    OpenAIRE

    Patel, Himanshu

    2008-01-01

    Poly(ethylene terephthalate) commonly known as PET has been a commercially important polymer since its introduction in 1950s and it is mainly used in fiber and packaging industries. It is mainly produced by synthesis of terephthalic acid (TPA) and ethylene glycol (EG). For PET synthesis, at first, primary esterification of TPA with EG takes place. The chain prolongation is further obtained by the reaction between carboxyl-groups (COOH) and ester-end groups (OH) of the oligomers (secondary est...

  19. 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...

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

    OpenAIRE

    Malek, F; 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(ε-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...

  1. 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

  2. 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(ε-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.

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

    International Nuclear Information System (INIS)

    Highlights: • Adsorption study of terephthalic acid (TPA) with MIES. • Flat adsorption of the molecules on gold. • Upright adsorption of the TPA molecules on oxidized aluminum. - Abstract: 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

  4. A New Process Modeling Method Based on Extension Theory and Its Application in Purified Terephthalic Acid Solvent System

    Science.gov (United States)

    Yuan, Xu; Qunxiong, Zhu

    Owing to the complexity and nonlinearity of chemical process, the intelligent process modeling has become a hot issue. For the purified terephthalic acid (PTA) solvent system, the acetic acid consumption is a crucial production index that has received much more attention in monitoring and guiding the production conditions. In this work, the focus is on the understanding and modeling the influence of operating conditions on acetic acid consumption, which is composed of matter-element model, extension transformation and general regression neural network (GRNN).Thus it comes to an extension engineering method for process modeling of chemical industry. Through the actual application in PTA solvent system of a chemical plant, cases studies show that the proposed method enables us to understand matters in an overall way, to describe thinking process of human beings in a formalized way, to model the chemical process precisely, which exploits a new way to simulate and guide the production process in chemical industry.

  5. Levulinic acid in organic synthesis

    International Nuclear Information System (INIS)

    Data concerning the methods of synthesis, chemical transformations and application of levulinic acid are analysed and generalised. The wide synthetic potential of levulinic acid, particularly as a key compound in the synthesis of various heterocyclic systems, saturated and unsaturated ketones and diketones, difficultly accessible acids and other compounds is demonstrated. The accessibility of levulinic acid from hexose-containing wood-processing and agricultural wastes is noted. The bibliography includes 260 references.

  6. 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

  7. Kojic acid in organic synthesis

    OpenAIRE

    Zirak, Maryam; EFTEKHARI-SIS, Bagher

    2015-01-01

    The reactions of kojic acid in organic synthesis are reviewed. The aim of this review is to cover the literature up to the end of 2014, showing the distribution of publications involving kojic acid chemistry in the synthesis of various pyrone containing compounds, pyridine and pyridone heterocycles, and also other organic compounds. First, introductory text about the preparation, biological, and industrial applications, and the chemical properties of kojic acid is given. Then its uses in orga...

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

    Energy Technology Data Exchange (ETDEWEB)

    Akyildiz, Halil I. [Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Mousa, Moataz Bellah M. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Jur, Jesse S., E-mail: jsjur@ncsu.edu [Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2015-01-28

    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-O{sub x} 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.

  9. 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

  10. 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.

  11. Acetate-assisted Synthesis of Chromium(III) Terephthalate and Its Gas Adsorption Properties

    International Nuclear Information System (INIS)

    We report a facile synthetic approach of high-quality chromium(III) terephthalate [MIL-101(Cr)] by acetate-assisted method in the absence of toxic HF. Results indicate that the morphology and surface area of the MIL-101(Cr) can be tuned by modifying the molar ratio of acetate/Cr(NO3)3. The Brunauer-Emmett-Teller (BET) surface area of MIL-101(Cr) synthesized at the optimized condition can exceed 3300 m2/g. It is confirmed that acetate could promote the dissolution of di-carboxylic linker and accelerate the nucleation ratio. So the pure and small size of MIL-101(Cr) with clean pores can be obtained. CO2, CH4 and N2 adsorption isotherms of the samples are studied at 298 K and 313 K. Compared with the traditional method, MIL-101(Cr) synthesized by acetate-assisted method possess enhanced CO2 selective adsorption capacity. At 1.0 bar 298 K, it exhibits 47% enhanced CO2 adsorption capacity. This may be attributed to the high surface area together with clean pores of MIL-101(Cr)

  12. 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.

  13. 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)

  14. Synthesis of Aromatic Polyester (Polyarylate) by Removal of Phenol from Condenatin Polymerization of Bisphenol A and Diphenyl Terephthalate/Isophthalate Mixtures; Bisufenoru A to jifeniruterefutarato/isofutarato kongobutsu tono jushukugo ni yoru hokozoku poriesuteru(poriarireto) no gosei

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Takashi. [Asahi CHemical Industry Crop., Okayama (Japan). Chemicals and Plastics Deveopment Laboratory; Kinoshita, Takashi,; Masamoto, Junzo. [Kyoto Institute of Tecnology, Kyoto (Japan). Department of Polymer Science and Engineering

    1999-01-10

    Industrially avaiable poly (bisphenol A arenedicarboxylate) Npolyarylate) is conventionally produced by the omterfacial condensation polymerization of bisphenol A and the mixture of terephthaloyl/isophthaloyl chlorides. We now report a new synthetic method without using the acid chloride derivatives, and the synthesis of oligomeric arenedicarboxylate by the melt condensation polymerization of bisphenol A and diphenyl terephthalte/isophthalate (mole ratio of reactants is 1/0.5/0.5). By removal of phenol from the reaction mixture, we obtained oligomeric ester, which can be changed to a high molecular weight polyester in the subsequent reactions. This report discussed the kenetics of the melt condensation of bisphenol A and diphenyl terephthalate/isophthalate mixtures. The melt condensation polymerization of bisphenol A and diphenyl terephthalate/isophthalate was analyzed by the bimolecular reaction of -OH and a phenyl ester. The activation energy was estimated to be 32.2 kcal/mol. The relationships between the reduced viscosity and molecular weight was estimated and the following experimental equation was obtained; {eta}{sub sp}/C=7.46x10{sup -5}M{sup 0.83}{sub w}. Polymer was analyzed by {sup 1}H-NMR, and the ratio of the end group of the hydroxy group to phenyl ester group was determined. FD-MS suggested four types of oligomeric ester end groups: phenyl-hydroxy, hydroxy-hydroxy, and cyclic. (author)

  15. 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.)

  16. 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

  17. Interaction of carboxylic acids with rutile TiO2(110): IR-investigations of terephthalic and benzoic acid adsorbed on a single crystal substrate

    Science.gov (United States)

    Buchholz, Maria; Xu, Mingchun; Noei, Heshmat; Weidler, Peter; Nefedov, Alexei; Fink, Karin; Wang, Yuemin; Wöll, Christof

    2016-01-01

    The adsorption of two carboxylic acids, benzoic acid (BA) and terephthalic acid (TPA), on a single crystal rutile TiO2(110) substrate was studied using infrared reflection-absorption spectroscopy (IRRAS) in conjunction with DFT calculations. On the basis of the high-quality IR data (in particular for the OH bands), various adsorbate species with different geometries could be identified. The adsorption of both, BA and TPA, on TiO2(110) leads to deprotonation of carboxylic acids and protonation of substrate O-atoms. At low coverage, the deprotonated BA molecule adsorbs on TiO2(110) in an upright, bidentate configuration, while the TPA molecule adopts a flat-lying geometry with both carboxylates bound to the surface in a monodentate geometry. At higher coverages, a transition from flat-lying to upright-oriented TPA molecules occurs. At saturation coverage, both BA and TPA molecules undergo dimerization indicating the presence of pronounced attractive intermolecular interactions. We propose that the BA dimers are stabilized by the interaction between adjacent phenyl rings, while the TPA dimerization is attributed to the formation of double hydrogen bonds between adjacent apical carboxylic groups.

  18. 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.

  19. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    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...... 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, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones...

  20. Chemical recycling of industrial poly(ethylene terephthalate) waste: synthesis of aromatic polyester polyols, their properties and use

    OpenAIRE

    Irena VITKAUSKIENÄ–

    2011-01-01

    In this study, the generation points, reasons and properties of industrial PET waste were examined in detail. Different chemical recycling ways were suggested for each kind of industrial PET waste. Under glycolysis of industrial PET waste by ethylene glycol, the yield of the main product bis(2-hidroxyethylene) terephthalate was higher than 85 %. Several series of aromatic polyester polyols (APP) were synthesized by transesterification of industrial PET waste using diethyleneglycol (DEG) in th...

  1. 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...

  2. Determination of zinc, cadmium, cobalt and nikel by flame atomic absorption spectrometry after preconcentration by poly(ethylene terephthalate) fibers grafted with methacrylic acid

    Science.gov (United States)

    Ba?, Hüseyin; Türker, A. Rehber; Co?kun, Ramazan; Saçak, Mehmet; Yi?ito?lu, Mustafa

    2000-07-01

    A method for the determination of Zn, Cd, Co and Ni by flame atomic absorption spectrophotometry after preconcentrating on poly(ethylene terephthalate) fibers grafted with methacrylic acid has been developed. The batch adsorption method was used for the preconcentration studies. Effect of pH, amount of adsorbent, concentration and volume of elution solution, shaking time and interfering ions on the recovery of the analytes have been investigated. Recoveries of Zn, Cd, Co and Ni were 97.3±0.4%, 98.3±0.2%, 94.1±0.3% and 96.5±0.6% at 95% confidence level, respectively, at optimum conditions. Langmuir adsorption isotherm curves were also studied for the analytes. The adsorption capacity of the adsorbent was found as 298, 412, 325 and 456 mg/g for Zn, Cd, Co and Ni, respectively. Poly(ethylene terephthalate) fibers grafted with methacrylic acid are suitable for repeated use without loss of capacity for more than thirty cycles. The proposed method was applied to the determination of trace metals in river water and synthetic sea water. Trace metals have been determined with high precision.

  3. Quantification of tetramethyl-terephthalic acid in rat liver, spleen and urine matrices by liquid-liquid phase extraction and HPLC-photodiode array detection.

    Science.gov (United States)

    Baati, Tarek; Horcajada, Patricia; David, Olivier; Gref, Ruxandra; Couvreur, Patrick; Serre, Christian

    2012-01-01

    Tetramethyl-terephthalate (TMT) is the constitutive linker of the flexible porous iron(III) carboxylate Metal Organic Framework (MOF) MIL-88B_4CH? based drug nanocarrier (MIL stands for Material from Institut Lavoisier). A method for the determination of the concentration of tetramethyl-terephthalic acid has been developed in different biological rat matrices (liver, spleen and urine) using a liquid-liquid phase extraction and high-performance liquid chromatography (HPLC) coupled to photodiode array detection with 4-aminosalicylic acid as internal standard. The extraction conditions of TMT have been varied from urine to tissue depending on the complexity of the biological matrices. The chromatographic separation was performed with a gradient elution. In all matrices, the limits of detection and quantification of TMT was 0.01 and 0.05 ?g ml?¹, respectively. The recovery of the TMT reached 86, 89 and 97% for urine, spleen and liver tissues, respectively. The linearity of the calibration curves in urine and tissues was satisfactory in all cases as evidenced by correlation coefficients >0.990. The within-day and between-day precisions were <15% (n=6) and the accuracy ranged in all cases between 86 and 103%. This method has finally allowed the quantification of TMT in rat urine and in tissue samples of rats administered intravenously with iron(III) tetramethyltherepthalate MIL-88B_4CH? nanoparticles. PMID:22608098

  4. 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.

  5. 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.

  6. 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.

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

    International Nuclear Information System (INIS)

    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.

  8. 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)

  9. Coexistence of one- and two-dimensional supramolecular assemblies of terephthalic acid on Pd(111) due to self-limiting deprotonation

    International Nuclear Information System (INIS)

    The adsorption of terephthalic acid [C6H4(COOH)2, TPA] on a Pd(111) surface has been investigated by means of scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy, and near-edge x-ray absorption fine structure spectroscopy under ultrahigh vacuum conditions at room temperature. We find the coexistence of one- (1D) and two-dimensional (2D) molecular ordering. Our analysis indicates that the 1D phase consists of intact TPA chains stabilized by a dimerization of the self-complementary carboxyl groups, whereas in the 2D phase, consisting of deprotonated entities, the molecules form lateral ionic hydrogen bonds. The supramolecular growth dynamics and the resulting structures are explained by a self-limiting deprotonation process mediated by the catalytic activity of the Pd surface. Our models for the molecular ordering are supported by molecular mechanics calculations and a simulation of high resolution STM images

  10. 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.

  11. Enantioselective total synthesis of (+)-lithospermic acid.

    Science.gov (United States)

    Ghosh, Arun K; Cheng, Xu; Zhou, Bing

    2012-10-01

    An enantioselective synthesis of (+)-lithospermic acid, a potent anti-HIV agent, has been accomplished in a convergent manner in nine steps. The synthesis features an enantioselective intramolecular oxa-Michael addition catalyzed by a quinidine derivative, a hypervalent iodine-mediated rearrangement of chromanone to dihydrobenzofuran, an enantioselective ?-oxyamination, and an intermolecular C-H olefination. PMID:22978790

  12. Synthesis and diagnostic use of ?-substituted fatty acids

    International Nuclear Information System (INIS)

    The application, evaluation and synthesis are discussed of the radioiodinated ?-substituted fatty acids used as myocardial imaging agents. The possibilities of the synthesis of all modifications of the radiolabelled fatty acids - ?-halogen acids, ?(p-iodophenyl) acids, ?-5-iodothienyl acids, ?-substituted ?- and ?-methyl-branched fatty acids, ?-iodoalkenyl fatty acids and ?-substituted tellurium fatty acids are demonstrated. The iodination methods are also included. (author)

  13. 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

  14. 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

  15. Enantioselective Total Synthesis of Secalonic Acid E.

    Science.gov (United States)

    Ganapathy, Dhandapani; Reiner, Johannes R; Löffler, Lorenz E; Ma, Ling; Gnanaprakasam, Boopathy; Niepötter, Benedikt; Koehne, Ingo; Tietze, Lutz F

    2015-11-16

    The first enantioselective synthesis of a secalonic acid containing a dimeric tetrahydroxanthenone skeleton is described, using a Wacker-type cyclization of a methoxyphenolic compound to form a chiral chroman with a quaternary carbon stereogenic center with >99% ee. Further steps are a Sharpless dihydroxylation and a Dieckmann condensation to give a tetrahydroxanthenone. A late-stage one-pot palladium-catalyzed Suzuki-dimerization reaction leads to the 2,2'-biphenol linkage to complete the enantioselective total synthesis of secalonic acid E in 18?steps with 8% overall yield. PMID:26447631

  16. Conducting polymer films fabricated by oxidative graft copolymerization of aniline on poly(acrylic acid) grafted poly(ethylene terephthalate) surfaces.

    Science.gov (United States)

    Wang, Jiku; Liu, Xuyan; Choi, Ho-Suk; Kim, Jong-Hoon

    2008-11-27

    A conductive polyaniline/poly(ethylene terephthalate) (PANI/PET) composite film was fabricated via the oxidative graft copolymerization of aniline (ANI) onto the plasma-induced poly(acrylic acid) (PAAc) grafted PET surface. The attenuated total reflectance Fourier transform infrared spectroscopy spectra (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results confirmed that PANI was successfully grafted onto the surface of the PAAc-g-PET films. The effects of the experimental conditions on the percentage of PANI grafted onto the PAAc-g-PET films were extensively investigated. A very high grafting percentage of ANI can be obtained through the acid-base reaction between the aniline monomer and PAAc on the PAAc-g-PET surface at high temperature. As a result, the grafting percentage of PANI can be increased to as high as 12.18 wt %, which causes the surface resistance of the PANI-g-PAAc-g-PET film to be reduced to about 1000 Omega/sq. We predicted that this is because of the high flexibility of the PAAc molecular chains and high solubility of aniline, both of which facilitate the binding of aniline to PAAc during this high temperature acid-base reaction. It was observed by atomic force microscopy (AFM) that the PANI-modified PET surface exhibits higher size irregularity and surface roughness, which further indicated that a much greater number of aniline molecules can be reactively bonded to and distributed along the grafted AAc chains and that the PANI-g-PAAc-g-PET surface resulting from the sequential oxidative graft copolymerization can possess higher electrical conductivity. PMID:18975893

  17. 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

  18. 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)

  19. 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.

  20. 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.

  1. Preparation, morphology and thermal properties of electrospun fatty acid eutectics/polyethylene terephthalate form-stable phase change ultrafine composite fibers for thermal energy storage

    International Nuclear Information System (INIS)

    Highlights: ► Electrospun binary fatty acid eutectics/PET ultrafine composite fibers were prepared. ► Fatty acid eutectics had appropriate phase transition temperature and heat enthalpy. ► Their morphological structures and thermal properties were different from each other. ► Composite fibers could be innovative form-stable PCMs for thermal energy storage. - Abstract: The ultrafine composite fibers based on the composites of binary fatty acid eutectics and polyethylene terephthalate (PET) with varied fatty acid eutectics/PET mass ratios (50/100, 70/100, 100/100 and 120/100) were fabricated using the technique of electrospinning as form-stable phase change materials (PCMs). The five binary fatty acid eutectics including LA–MA, LA–PA, MA–PA, MA–SA and PA–SA were prepared according to Schrader equation, and then were selected as an innovative type of solid–liquid PCMs. The results characterized by differential scanning calorimeter (DSC) indicated that the prepared binary fatty acid eutectics with low phase transition temperatures and high heat enthalpies for climatic requirements were more suitable for applications in building energy storage. The structural morphologies, thermal energy storage and thermal stability properties of the ultrafine composite fibers were investigated by scanning electron microscope (SEM), DSC and thermogravimetric analysis (TGA), respectively. SEM images revealed that the electrospun binary fatty acid eutectics/PET ultrafine composite fibers possessed the wrinkled surfaces morphologies compared with the neat PET fibers with cylindrical shape and smooth surfaces; the grooves or ridges on the corrugated surface of the ultrafine composite fibers became more and more prominent with increasing fatty acid eutectics amount in the composite fibers. The fibers with the low mass ratio maintained good structural morphologies while the quality became worse when the mass ratio is too high (more than 100/100). DSC measurements suggested that the heat enthalpies of melting and crystallization of the ultrafine composite fibers increased gradually with increasing fatty acid eutectics amounts, but their phase transition temperatures had almost no obvious variation as relative to the corresponding fatty acid eutectics. Meanwhile, the characteristic temperatures and heat enthalpies of the ultrafine composite fibers varied with the different types of binary fatty acid eutectics. TGA results indicated that the degradation of electrospun binary fatty acid eutectics/PET ultrafine composite fibers with representative mass ratio of 100/100 had two steps and corresponded respectively to the degradations of binary fatty acid eutectics and PET polymer chains; and the charred residue at 700 °C of the composite fibers was lower than that of the neat PET fibers. It could be envisioned that the electrospun binary fatty acid eutectics/PET composite fibers would be extensively used for latent heat storage in the field of building energy conservation.

  2. 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

  3. Synthesis of carbon-13-labeled tetradecanoic acids.

    Science.gov (United States)

    Sparrow, J T; Patel, K M; Morrisett, J D

    1983-07-01

    The synthesis of tetradecanoic acid enriched with 13C at carbons 1, 3, or 6 is described. The label at the carbonyl carbon was introduced by treating 1-bromotridecane with K13CN (90% enriched) to form the 13C-labeled nitrile, which upon hydrolysis yielded the desired acid. The [3-13C]tetradecanoic acid was synthesized by alkylation of diethyl sodio-malonate with [1-13C]1-bromododecane; the acid was obtained upon saponification and decarboxylation. The label at the 6 position was introduced by coupling the appropriately labeled alkylcadmium chloride with the half acid chloride methyl ester of the appropriate dioic acid, giving the corresponding oxo fatty acid ester. Formation of the tosylhydrazone of the oxo-ester followed by reduction with sodium cyanoborohydride gave the labeled methyl tetradecanoate which, upon hydrolysis, yielded the desired tetradecanoic acid. All tetradecanoic acids were identical to unlabeled analogs as evaluated by gas-liquid chromatography and infrared or NMR spectroscopy. These labeled fatty acids were used subsequently to prepare the correspondingly labeled diacyl phosphatidylcholines. PMID:6631228

  4. Corrosion of an amorphous indium tin oxide film on polyethylene terephthalate at low concentrations of acrylic acid

    International Nuclear Information System (INIS)

    Highlights: â–º Corrosion of ITO film on polymer substrate. â–º Removal of In from ITO in acrylic acid. â–º Degradation of conductivity of ITO film with acrylic adhesives. - Abstract: The corrosion behavior of ITO film deposited at low temperature on a polymer substrate by DC magnetron sputtering is studied in 0.05 M acrylic acid to investigate possible corrosion in contact with acrylic adhesives, which are employed in the fabrication of flexible optoelectronic devices. The shift in steady state open circuit potential (OCP) to negative values in electrochemical measurements suggests the increase in dissolution of ITO film with increasing immersion time. The potentiodynamic polarization results show an increase in Ecorr and a decrease in Icorr to lower values with time. This suggests that the electro-activity of ITO film decreases with increasing immersion time. Scanning electron microscopy shows corrosion of the ITO film. X-ray photoelectron spectroscopy analysis indicates a gradual removal of indium from the ITO layer. Electrochemical impedance spectroscopy analysis reveals two time constants and an increase in the charge transfer resistance of the Nyquist plot which suggests a decrease in the conductivity of ITO film with increasing immersion time. Both the electrochemical and surface characterization studies suggest a degradation of the conductivity of ITO film with increasing immersion time in 0.05 M acrylic acid.

  5. Synthesis of Lipoteichoic Acids in Bacillus anthracis

    OpenAIRE

    Garufi, Gabriella; Hendrickx, Antoni P.; Beeri, Karen; Kern, Justin W.; Sharma, Anshika; Richter, Stefan G.; Schneewind, Olaf; Missiakas, Dominique

    2012-01-01

    Lipoteichoic acid (LTA), a glycerol phosphate polymer, is a component of the envelope of Gram-positive bacteria that has hitherto not been identified in Bacillus anthracis, the causative agent of anthrax. LTA synthesis in Staphylococcus aureus and other microbes is catalyzed by the product of the ltaS gene, a membrane protein that polymerizes polyglycerol phosphate from phosphatidyl glycerol. Here we identified four ltaS homologues, designated ltaS1 to -4, in the genome of Bacillus anthracis....

  6. 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...

  7. Features of fatty acid synthesis in higher plants

    International Nuclear Information System (INIS)

    In the biosynthesis of fatty acid in the presence of 3H2O, 3H is incorporated into the hydrocarbon chain of the fatty acid. The features in the fatty acid synthesis of higher plants were investigated by applying 3H2O method to the measurement of the ability of spinach leaves synthesizing fatty acid. Sucrose, acetate, pyruvate, PGA, PEP, OAA, citrate, etc. were employed as the substrates of fatty acid synthesis to trace the process of synthesis of each fatty acid. The demand of various cofactors related to the ability of spinach chloroplast fatty acid synthesizing was also examined. Light dependence of the fatty acid synthesis of chloroplast as well as the influences of N,N'-dicyclohexyl carbodiimide, carbonylcyanide-4-trifluoromethoxy phenyl hydrazone and NH4Cl were discussed. The results were compared with the reports on the fatty acid synthesis of avocado pear, castor bean, etc. (Kobatake, H.)

  8. 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

  9. 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...

  10. 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)

  11. Photo destruction of polyethylene terephthalate

    International Nuclear Information System (INIS)

    Present article is devoted to photo destruction of polyethylene terephthalate. The photo destruction of polyethylene terephthalate was studied by means of different methods under the conditions of irradiation of fibers in the open air and in the vacuum by wide ultraviolet spectre and monochromatic radiation.

  12. 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

  13. Synthesis of 3C–SiC nanowires by reaction of poly(ethylene terephthalate) waste with SiO{sub 2} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Lei; Zhong, Hao; Chen, Qianwang, E-mail: cqw@ustc.edu.cn

    2013-07-25

    Highlights: •The 3C–SiC nanowires have been synthesized by reaction of poly(ethylene terephthalate) (PET) waste and SiO{sub 2} 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 SiO{sub 2} 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. Catalysis of the Carbonylation of Alcohols to Carboxylic Acids Including Acetic Acid Synthesis from Methanol.

    Science.gov (United States)

    Forster, Denis; DeKleva, Thomas W.

    1986-01-01

    Monsanto's highly successful synthesis of acetic acid from methanol and carbon monoxide illustrates use of new starting materials to replace pretroleum-derived ethylene. Outlines the fundamental aspects of the acetic acid process and suggests ways of extending the synthesis to higher carboxylic acids. (JN)

  19. 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.

  20. 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.

  1. A bacterium that degrades and assimilates poly(ethylene terephthalate).

    Science.gov (United States)

    Yoshida, Shosuke; Hiraga, Kazumi; Takehana, Toshihiko; Taniguchi, Ikuo; Yamaji, Hironao; Maeda, Yasuhito; Toyohara, Kiyotsuna; Miyamoto, Kenji; Kimura, Yoshiharu; Oda, Kohei

    2016-03-11

    Poly(ethylene terephthalate) (PET) is used extensively worldwide in plastic products, and its accumulation in the environment has become a global concern. Because the ability to enzymatically degrade PET has been thought to be limited to a few fungal species, biodegradation is not yet a viable remediation or recycling strategy. By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, that is able to use PET as its major energy and carbon source. When grown on PET, this strain produces two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. Both enzymes are required to enzymatically convert PET efficiently into its two environmentally benign monomers, terephthalic acid and ethylene glycol. PMID:26965627

  2. 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}.

  3. 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)

  4. 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)

  5. 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

  6. 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)

  7. Synthesis of Orthogonally Protected Muramic Acid Building Blocks for Solid Phase Peptide Synthesis

    OpenAIRE

    Vlahovi?ek-Kahlina, Kristina; Jakas, Andreja

    2015-01-01

    Muramic acid is found in many peptide natural products containing oligo(poly)saccharide moieties. Taking into consideration that the Fmoc methodology is routinely used for solid-phase peptide synthesis, preparation of orthogonally protected muramic acid building blocks for total solid-phase synthesis of these natural products is of particular practical importance. Herein a simple and efficient synthesis of benzyl 2-amino-4,6-O-benzylidene-3-O-[(R)-1-carboxyethyl]-2-deoxy-N-9-fluorenylmethylox...

  8. 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.

  9. Convenient synthesis of optically pure ?-mono and ?,?-disubstituted ?-amino acids

    International Nuclear Information System (INIS)

    Optically pure ?-mono-and ?,?-disubstituted ?-amino acids were conveniently prepared in four steps and in 27-40% overall yields from the correspondingly substituted racemic ?-hydroxy acids that can be readily obtained from diethyl malonate. In the synthesis, (S)-phenylethylamine has been used as a resolving agent and as a source of the amino group in the ?-amino acids

  10. Automated solid-phase synthesis of oligosaccharides containing sialic acids

    Directory of Open Access Journals (Sweden)

    Chian-Hui Lai

    2015-05-01

    Full Text Available A sialic acid glycosyl phosphate building block was designed and synthesized. This building block was used to prepare ?-sialylated oligosaccharides by automated solid-phase synthesis selectively.

  11. 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)

  12. 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)

  13. 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...

  14. 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.

  15. 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.

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

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    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....

  17. 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.

  18. Nucleic acid arrays and methods of synthesis

    Science.gov (United States)

    Sabanayagam, Chandran R. (Allston, MA); Sano, Takeshi (Needham, MA); Misasi, John (Syracuse, NY); Hatch, Anson (Seattle, WA); Cantor, Charles (Del Mar, CA)

    2001-01-01

    The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

  19. 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)

  20. 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

  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. 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 ...

  3. 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...

  4. 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...

  5. 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...

  6. 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 beha...

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. 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...

  15. 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)

  16. Synthesis of [14CO]ellagic acid

    International Nuclear Information System (INIS)

    [14CO]Ellagic acid with a chemical purity of 98.9% and radiochemical purity of 99.9% was synthesized with an overall yield of 16% (both chemically and radiochemically). Reaction of 14CO2 with lithiated 3,4,5-trimethoxybenzene and demethylation of the resulting 3,4,5-trimethoxybenzoic acid was followed by esterification and coupling of methyl gallate into ellagic acid. Two efficient coupling methods were employed: direct aeration and aeration of methyl gallate in the presence of the phenolic oxidase, tyrosinase. The latter method produced the highest yield and purity. This preparation produced [14CO]ellagic acid with a specific activity of 20 mCi/mmol. The yields of labeled 3,4,5-trimethoxybenzoic acid and ellagic acid based on Ba14CO3 were 65% and 16%, respectively. (author)

  17. 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

  18. Synthesis of itaconic acid from the irradiation of aconitic acid-clay suspensions

    International Nuclear Information System (INIS)

    The radiolysis of aconitic acid in aqueous solution and in water-clay suspensions was studied. Among the radiolytic products, itaconic acid (HO2C-C(=CH2)-CH2CO2H) was formed. Itaconic acid is a valuable monomer in the formulation of polymers. The synthesis of itaconic acid can be achieved in one step using aqueous solutions of aconitic acid and in water-clay suspensions exposed to ionizing radiation. The yield of formation does not compete with fermentation procedures for the synthesis of itaconic acid, but for laboratory purposes is a very simple method to prepare it. Other products of the radiolysis were carbon dioxide, tricarballylic and citric/isocitric acids. (Author)

  19. 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...

  20. 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)...

  1. 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)

  2. 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.

  3. The spark discharge synthesis of amino acids from various hydrocarbons

    Science.gov (United States)

    Ring, D.; Miller, S. L.

    1984-01-01

    The spark discharge synthesis of amino acids using an atmosphere of CH4+N2+H2O+NH3 has been investigated with variable pNH3. The amino acids produced using higher hydrocarbons (ethane, ethylene, acetylene, propane, butane, and isobutane) instead of CH4 were also investigated. There was considerable range in the absolute yields of amino acids, but the yields relative to glycine (or alpha-amino-n-butyric acid) were more uniform. The relative yields of the C3 to C6 aliphatic alpha-amino acids are nearly the same (with a few exceptions) with all the hydrocarbons. The glycine yields are more variable. The precursors to the C3-C6 aliphatic amino acids seem to be produced in the same process, which is separate from the synthesis of glycine precursors. It may be possible to use these relative yields as a signature for a spark discharge synthesis provided corrections can be made for subsequent decomposition events (e.g. in the Murchison meteorite).

  4. 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

  5. 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

  6. Selective Synthesis of Citric Acid from Molasses using Aspergillus Niger

    Directory of Open Access Journals (Sweden)

    Jayant.K.Pohnerkar

    2014-03-01

    Full Text Available Selective synthesis of Citric Acid from local cane molasses using Aspergillus niger was studied. A local stain of A.niger isolated from lemon tree leaves & cultured. A.niger stain ATCC-595 were separately studied for the Bioconversion of local molasses into citric acid. The molasses fermentation was carried out at 30°C in a flask. The results showed increased efficiency for citric acid production when compared with wild type. It produced 210.12 gm/lit of citric acid as compared to wild stain 102.5 gm/lit. The maximum citric acid production is on the 9th day of fermentation by used stain and 11th day by the wild type. This investigation is one of the ecofriendly technology can be used for economic development & environmental protection in india. By recycling & reusing waste material from cane Industries Citric acid production can be easily done.

  7. 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.

  8. 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.

  9. Glucose and Insulin Induction of Bile Acid Synthesis

    Science.gov (United States)

    Li, Tiangang; Francl, Jessica M.; Boehme, Shannon; Ochoa, Adrian; Zhang, Youcai; Klaassen, Curtis D.; Erickson, Sandra K.; Chiang, John Y. L.

    2012-01-01

    Bile acids facilitate postprandial absorption of nutrients. Bile acids also activate the farnesoid X receptor (FXR) and the G protein-coupled receptor TGR5 and play a major role in regulating lipid, glucose, and energy metabolism. Transgenic expression of cholesterol 7?-hydroxylase (CYP7A1) prevented high fat diet-induced diabetes and obesity in mice. In this study, we investigated the nutrient effects on bile acid synthesis. Refeeding of a chow diet to fasted mice increased CYP7A1 expression, bile acid pool size, and serum bile acids in wild type and humanized CYP7A1-transgenic mice. Chromatin immunoprecipitation assays showed that glucose increased histone acetylation and decreased histone methylation on the CYP7A1 gene promoter. Refeeding also induced CYP7A1 in fxr-deficient mice, indicating that FXR signaling did not play a role in postprandial regulation of bile acid synthesis. In streptozocin-induced type I diabetic mice and genetically obese type II diabetic ob/ob mice, hyperglycemia increased histone acetylation status on the CYP7A1 gene promoter, leading to elevated basal Cyp7a1 expression and an enlarged bile acid pool with altered bile acid composition. However, refeeding did not further increase CYP7A1 expression in diabetic mice. In summary, this study demonstrates that glucose and insulin are major postprandial factors that induce CYP7A1 gene expression and bile acid synthesis. Glucose induces CYP7A1 gene expression mainly by epigenetic mechanisms. In diabetic mice, CYP7A1 chromatin is hyperacetylated, and fasting to refeeding response is impaired and may exacerbate metabolic disorders in diabetes. PMID:22144677

  10. Photolabile linker for the synthesis of hydroxamic acids

    DEFF Research Database (Denmark)

    The present invention relates to a photolabile hydroxamate linker based on the o - nitroveratryl group and its application for multistep solid-phase synthesis and controlled photolytic release of hydroxamic acids. The invention provides a method for producing a solid support comprising a...... hydroxylamine - functionalized photolabile linker, and the so produced hydroxylamine - functionalized photolabile solid support. The invention further provides a method for synthesizing a one-bead-one compound library of hydroxamic acid derivatives on a photolabile linker, as well as a method for screening a...... library of hydroxamic acid derivatives....

  11. 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

  12. Synthesis of azido derivatives of mucobromic acid

    Directory of Open Access Journals (Sweden)

    N. Mbebe

    2013-04-01

    Full Text Available Mucobromic acid is a highly reactive multicentered molecule. It was converted to its corresponding but unstable diazido derivative by reaction with two equivalents of sodium azide. The resultant 3,4-diazido-5-hydroxyfuran-2(5H-one was obtained in moderate yield (42% but decomposed readily even at low temperatures. Its more stable analogue 3,4-diazido-5-methoxyfuran-2(5H-one was obtained in excellent yield after reacting 5-methoxy-3,4-dibromofuranone with two equivalents of sodium azide. The 4,5-dibromopyridazinones which are in effect masked mucobromic acid derivatives, underwent nucleophilic substitution reactions with various nucleophiles, including azides and afforded corresponding azidopyridazinones in good yields. The synthesized azido-furanone and pyridazinone derivatives are earmarked for click reactions.DOI: http://dx.doi.org/10.4314/bcse.v27i1.17

  13. 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

  14. Inhibition of polyketide synthesis in Alternaria alternata by the fatty acid synthesis inhibitor cerulenin.

    OpenAIRE

    Hiltunen, M. (Maarit); SÖDERHÄLL K.

    1992-01-01

    The fatty acid synthase inhibitor cerulenin (50 to 100 micrograms/ml) inhibited production of the polyketide mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) by the mold Alternaria alternata. The results suggested that AOH synthesis was inhibited by a direct mechanism by cerulenin, whereas production of AME was probably limited by a shortage of the precursor AOH.

  15. Advances in catalytic production of bio-based polyester monomer 2,5-furandicarboxylic acid derived from lignocellulosic biomass.

    Science.gov (United States)

    Zhang, Junhua; Li, Junke; Tang, Yanjun; Lin, Lu; Long, Minnan

    2015-10-01

    Recently, the production and utilization of 2,5-furandicarboxylic acid (FDCA) have become a hot research topic in catalyst field and polyester industry for its special chemical structure and a wide range of raw material source. FDCA is a potential replacement for the terephthalic acid monomer used in the production of poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), which opens up a new pathway for obtaining biomass-based polyester to replace or partially replace petroleum based polyester. Here, we mainly reviewed the catalytic pathway for the synthesis of FDCA derived from lignocellulosic biomass or from the related downstream products, such as glucose, 5-hydroxymethylfurfural (HMF). Moreover, the utilization of oxidation catalysts, the reaction mechanism, the existing limitations and unsolved challenges were also elaborated in detail. Therefore, we hope this mini review provides a helpful overview and insight to readers in this exciting research area. PMID:26076643

  16. Multienzymatic synthesis of nucleic acid derivatives: a general perspective.

    Science.gov (United States)

    Fernández-Lucas, Jesús

    2015-06-01

    Living cells are most perfect synthetic factory. The surprising synthetic efficiency of biological systems is allowed by the combination of multiple processes catalyzed by enzymes working sequentially. In this sense, biocatalysis tries to reproduce nature's synthetic strategies to perform the synthesis of different organic compounds using natural catalysts such as cells or enzymes. Nowadays, the use of multienzymatic systems in biocatalysis is becoming a habitual strategy for the synthesis of organic compounds that leads to the realization of complex synthetic schemes. By combining several steps in one pot, a significant step economy can be realized and the potential for environmentally benign synthesis is improved. Using this sustainable synthetic system, several work-up steps can be avoided and pure products are ideally isolated after a series of reactions in one single vessel after just one straightforward purification step. In recent years, enzymatic methodology for the preparation of nucleic acid derivatives (NADs) has become a standard technique for the synthesis of a wide variety of natural NADs. Enzymatic methods have been shown to be an efficient alternative for the synthesis of nucleoside and nucleotide analogs to the traditional multistep chemical methods, since chemical glycosylation reactions include several protection-deprotection steps and the use of chemical reagents and organic solvents that are expensive and environmentally harmful. In this minireview, we want to illustrate what we consider the most current relevant examples of in vivo and in vitro multienzymatic systems used for the synthesis of nucleic acid derivatives showing advantages and disadvantages of each methodology. Finally, a detailed perspective about the impact of -omics in multienzymatic systems has been described. PMID:25952113

  17. Synthesis of azido derivatives of mucobromic acid

    OpenAIRE

    N. Mbebe; W. Masamba; N.D. Jumbam

    2013-01-01

    Mucobromic acid is a highly reactive multicentered molecule. It was converted to its corresponding but unstable diazido derivative by reaction with two equivalents of sodium azide. The resultant 3,4-diazido-5-hydroxyfuran-2(5H)-one was obtained in moderate yield (42%) but decomposed readily even at low temperatures. Its more stable analogue 3,4-diazido-5-methoxyfuran-2(5H)-one was obtained in excellent yield after reacting 5-methoxy-3,4-dibromofuranone with two equivalents of sodium azide. Th...

  18. Photolabile linker for the synthesis of hydroxamic acids

    OpenAIRE

    Nielsen, Thomas Eiland; Qvortrup, Katrine

    2013-01-01

    The present invention relates to a photolabile hydroxamate linker based on the o - nitroveratryl group and its application for multistep solid-phase synthesis and controlled photolytic release of hydroxamic acids. The invention provides a method for producing a solid support comprising a hydroxylamine - functionalized photolabile linker, and the so produced hydroxylamine - functionalized photolabile solid support. The invention further provides a method for synthesizing a one-bead-one compoun...

  19. 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...

  20. SYNTHESIS OF HYDROGELS CONTAINING INDOLBUTYRIC ACID AS ROOTING AUXIN

    Scientific Electronic Library Online (English)

    DIETER, KLATTENHOFF; RENE, ESCOBAR; EDUARDO, ALISTE.

    2006-06-01

    Full Text Available This article is devoted to the synthesis and characterization of acrylamide-acrylic acid hydrogels containing indolbutyric acid (IBA) as rooting auxin by two different methods. In the first alternative, the hormone is incorporated in the reagents mixture before polymerization, and in the second one, [...] IBA become incorporated through a dry hydrogel hydration in a hormone ethanol-water solution. In both cases the quantity of IBA incorporated to the gel is determined and interrelated with IBA concentration in the mixtures and solutions

  1. Synthesis of rosin acid starch catalyzed by lipase.

    Science.gov (United States)

    Lin, Rihui; Li, He; Long, Han; Su, Jiating; Huang, Wenqin

    2014-01-01

    Rosin, an abundant raw material from pine trees, was used as a starting material directly for the synthesis of rosin acid starch. The esterification reaction was catalyzed by lipase (Novozym 435) under mild conditions. Based on single factor experimentation, the optimal esterification conditions were obtained as follows: rosin acid/anhydrous glucose unit in the molar ratio 2:1, reaction time 4 h at 45°C, and 15% of lipase dosage. The degree of substitution (DS) reaches 0.098. Product from esterification of cassava starch with rosin acid was confirmed by FTIR spectroscopy and iodine coloration analysis. Scanning electron microscopy and X-ray diffraction analysis showed that the morphology and crystallinity of the cassava starch were largely destroyed. Thermogravimetric analysis indicated that thermal stability of rosin acid starch decreased compared with native starch. PMID:24977156

  2. Facile Synthesis of Oleanolic Acid Monoglycosides and Diglycosides

    Directory of Open Access Journals (Sweden)

    Mao-Sheng Cheng

    2008-07-01

    Full Text Available Oleanolic acid and its glycosides are important natural products, possessing various attractive biological activities such as antitumor, antivirus and anti-inflammatory properties. In the present work, fifteen oleanolic acid saponins bearing various saccharide moieties, including 3-monoglycoside, 28-monoglycoside and 3,28-diglycoside, were easily synthesized in high yields. Benzyl was chosen as the protective group for the COOH(28 group, instead of commonly used methyl and allyl, to avoid difficulties in the final deprotection. Alkali-promoted condensation of the carboxylic acid with bromoglycosides was found to be more efficient in the synthesis of 28-glycosides. Two approaches were investigated and proved practicable in the preparation of 3,28- diglycosides. This method is suitable for preparing oleanolic acid glycosides with structural diversity for extensive biological evaluation and structure-activity relationship study, and it also apply new idea for the corresponding synthetic methods to the glycoside derivatives of other triterpenoid.

  3. 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.

  4. Tailored fatty acid synthesis via dynamic control of fatty acid elongation

    OpenAIRE

    Torella, Joseph P.; Tyler J. Ford; Kim, Scott N.; Chen, Amanda M.; Way, Jeffrey C; Silver, Pamela A

    2013-01-01

    Medium-chain fatty acids (MCFAs, 4–12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even- and odd-chain–length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, there...

  5. 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.

  6. 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...

  7. Design and Synthesis of a Dual Linker for Solid Phase Synthesis of Oleanolic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Shaorong Wang

    2011-06-01

    Full Text Available A hydrophilic amino-terminated poly(ethylene glycol-type dual linker for solid phase synthesis of oleanolic acid derivatives using trityl chloride resin was designed and synthesized for the first time. Model reactions in both liquid and solid phase were performed to show the feasibility of its selective cleavage at two different sites. The biological assay results indicated that the long and flexible alkyl ether functionality in the linker is less likely to be critical for the binding event. Following the successful solid-phase synthesis of model compounds, the potential of this dual linker in reaction monitoring and target identification is deemed worthy of further study.

  8. Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A; Synthese de derives de l'acide tetronique et de l'acide pulvinique. Synthese totale de la norbadione A

    Energy Technology Data Exchange (ETDEWEB)

    Mallinger, A

    2008-11-15

    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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Protein and RNA synthesis in kainic acid-injected striata

    International Nuclear Information System (INIS)

    Injections of kainic acid into rat neostriata destroy neuronal soma in the injected area. Kainic acid-injected neostriata show a significant increase (as compared with control) in the incorporation in vitro of label from radioactive leucine into the TCA-insoluble protein fraction at all time periods studied (from 1 to 80 days after the kainic acid injection), with the greatest stimulation (6-7-fold) occurring between the third and eighth day. At 1-5 days there was also increased incorporation in vitro of label from uridine into RNA. The increased protein synthesis is probably due to the astrocytes which invade the injected area and are still seen in electron microscopic studies 2-3 months after the injections. (Auth.)

  14. 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

  15. 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.

  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. Stereoselective synthesis of uridine-derived nucleosyl amino acids.

    Science.gov (United States)

    Spork, Anatol P; Wiegmann, Daniel; Granitzka, Markus; Stalke, Dietmar; Ducho, Christian

    2011-12-16

    Novel hybrid structures of 5'-deoxyuridine and glycine were conceived and synthesized. Such nucleosyl amino acids (NAAs) represent simplified analogues of the core structure of muraymycin nucleoside antibiotics, making them useful synthetic building blocks for structure-activity relationship (SAR) studies. The key step of the developed synthetic route was the efficient and highly diastereoselective asymmetric hydrogenation of didehydro amino acid precursors toward protected NAAs. It was anticipated that the synthesis of unprotected muraymycin derivatives via this route would require a suitable intermediate protecting group at the N-3 of the uracil base. After initial attempts using PMB- and BOM-N-3 protection, both of which resulted in problematic deprotection steps, an N-3 protecting group-free route was envisaged. In spite of the pronounced acidity of the uracil-3-NH, this route worked equally efficient and with identical stereoselectivities as the initial strategies involving N-3 protection. The obtained NAA building blocks were employed for the synthesis of truncated 5'-deoxymuraymycin analogues. PMID:22059552

  19. 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.

  20. 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.

  1. 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

  2. Synthesis and Radioprotective Properties of Pulvinic Acid Derivatives

    International Nuclear Information System (INIS)

    A high-throughput screening method has highlighted the marked antioxidant activity of some pulvinic acid derivatives (PADs) towards oxidation of thymidine, under ? and UV irradiation, and Fenton-like conditions. Here, we report the synthesis of a series of new hydrophilic PADs and the evaluation of their radioprotective efficacy in cell culture. Using a cell-based fluorescent assay, we show that some of these compounds have a pronounced ability to prevent cell death caused by radiation and to allow the subsequent resumption of proliferation. Thus, PADs may be considered as a novel class of radioprotective agents. (authors)

  3. 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

  4. 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.

  5. Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

    Directory of Open Access Journals (Sweden)

    Roman Matthessen

    2014-10-01

    Full Text Available The near-unlimited availability of CO2 has stimulated a growing research effort in creating value-added products from this greenhouse gas. This paper presents the trends on the most important methods used in the electrochemical synthesis of carboxylic acids from carbon dioxide. An overview is given of different substrate groups which form carboxylic acids upon CO2 fixation, including mechanistic considerations. While most work focuses on the electrocarboxylation of substrates with sacrificial anodes, this review considers the possibilities and challenges of implementing other synthetic methodologies. In view of potential industrial application, the choice of reactor setup, electrode type and reaction pathway has a large influence on the sustainability and efficiency of the process.

  6. 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.

  7. 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...

  8. 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

  9. 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

  10. Cyclic diguanylic acid and cellulose synthesis in Agrobacterium tumefaciens

    International Nuclear Information System (INIS)

    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 cellulose during growth in the absence of plant cells, and this capacity was retained in resting cells. Synthesis of a cellulosic product from UDP-glucose in vitro with membrane preparations was markedly stimulated by c-di-GMP and its precursor GTP and was further enhanced by Ca2+. The calcium effect was attributed to inhibition of a c-di-GMP-degrading enzyme shown to be present in the cellulose synthase-containing membranes

  11. 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 ...

  12. [Polyethylene terephthalate (PET)--health aspects and food packaging application].

    Science.gov (United States)

    Cwiek-Ludwicka, Kazimiera

    2003-01-01

    Polyethylene terephthalate (PET) due to its physicochemical properties, especially regidity and glass-like transparency is widely used as food packaging material. The relevant legislation states that substances may not migrate from food contacting materials in quantities that may cause undesirable changes in organoleptic properties of food coming into contact with such material. The lists of substances authorized for food contact plastic materials and requirements for the final product were established. The requirements concern global migration limits (60 mg/kg or 10 mg/dm2) and specific migration limits (SML) set for substances which, when migrate into food in grater quantities may cause risk for human health. For the products manufactured from PET the specific migration limits were set for terephthalic acid (7.5 mg/kg), for isophthalic acid (5 mg/kg), for isophthalic acid dimethyl ester (0.05 mg/kg) and for ethylene and diethylene glycol (30 mg/kg). PET may undergo thermal degradation resulting in formation of acetaldehyde, which may influence organoleptic characteristics of packaged foods changing taste and smell. PMID:14531083

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

    OpenAIRE

    O'Reilly, Elaine; Pes, Lara; Ortin, Yannick; Müller-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...

  14. 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...

  15. recA gene product is responsible for inhibition of deoxyribonucleic acid synthesis after ultraviolet irradiation.

    OpenAIRE

    Trgovcević, Z; Petranović, D.; Petranović, M; Salaj-Smic, E

    1980-01-01

    Deoxyribonucleic acid synthesis after ultraviolet irradiation was studied in wild-type, uvrA, recB, recA recB, and recA Escherichia coli strains. Inhibition of deoxyribonucleic acid synthesis, which occurs almost immediately after exposing the cells to ultraviolet radiation, depends on the functional gene recA.

  16. 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)

  17. Nogalamycin Inhibits Ribonucleic Acid Synthesis in Growing and Developing Cells of the Slime Mold Dictyostelium discoideum

    OpenAIRE

    Ennis, H L

    1981-01-01

    Nogalamycin, an anthracycline antibiotic that intercalates into deoxyribonucleic acid, is a potent inhibitor of ribonucleic acid (RNA) synthesis in the slime mold Dictyostelium discoideum. The antibiotic inhibits RNA synthesis in growing cells and in inactivated spores, and in this way inhibits spore germination. Protein synthesis is much less inhibited. Nogalamycin inhibits ribosomal RNA, transfer RNA, and messenger RNA equally. Polysomes break down in the presence of the drug with a half-li...

  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. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Injury-induced inhibition of small intestinal protein and nucleic acid synthesis

    International Nuclear Information System (INIS)

    Small intestinal mucosal weight and nutrient absorption are significantly diminished early after cutaneous thermal injuries. Because these intestinal properties are highly dependent on rates of nucleic acid and protein synthesis, in vivo incorporation of thymidine, uridine, and leucine into small intestinal deoxyribonucleic acid, ribonucleic acid, and proteins were measured. Deoxyribonucleic acid synthesis was markedly decreased with the lowest thymidine incorporation in the jejunum (p less than 0.01); these findings were confirmed by autoradiographic identification of radiolabeled nuclei in the intestinal crypts. Protein synthesis was decreased by 6 h postinjury (p less than 0.01) but had returned to normal by 48 h. Consistent with a decreased rate of protein synthesis, ribonucleic acid synthesis was also decreased 18 h postinjury (p less than 0.01). These decreased deoxyribonucleic acid, ribonucleic acid, and protein synthesis rates are not likely a result of ischemia because in other studies of this injury model, intestinal blood flow was not significantly changed by the burn injury. Potentially, factors initiating the acute inflammatory reaction may directly inhibit nucleic acid and protein synthesis and lead to alterations in nutrient absorption and intestinal barrier function after injury

  5. Malonic ester and acetoacetic ester synthesis of 2-[11,14C]methyl-fatty acids

    International Nuclear Information System (INIS)

    Suitable conditions were sought for the synthesis of various 2-[11,14C]methyl-fatty acids by malonic ester synthesis and acetoacetic ester synthesis, both involving radio-methylation with [11,14C]CH3I. The malonic ester synthesis gave 2-[11C]methyl-fatty acids with over 60% decay-corrected yields in about 40 min and the [14C]products with somewhat higher yields at a longer time. In the acetoacetic ester synthesis, several 2-[14C]methyl-fatty acids were synthesized in 50-70% yields by the hydrolysis of the radio-methylated acetoacetates with a concentrated potassium hydroxide solution, together with by-product ketones. This hydrolysis was completed in 5 min at 70oC, whereas rather drastic conditions or a longer time were needed for the thermal decarboxylation in the malonic ester synthesis. (author)

  6. Enzymatic synthesis and application of fatty acid ascorbyl esters

    Directory of Open Access Journals (Sweden)

    Stojanović 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.

  7. 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.

  8. 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)

  9. 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...

  10. 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

  11. 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.

  12. 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'')...

  13. 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.

  14. 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...

  15. Tailored fatty acid synthesis via dynamic control of fatty acid elongation

    Energy Technology Data Exchange (ETDEWEB)

    Torella, JP; Ford, TJ; Kim, SN; Chen, AM; Way, JC; Silver, PA

    2013-07-09

    Medium-chain fatty acids (MCFAs, 4-12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even-and odd-chain-length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, thereby slowing acyl-ACP elongation and redirecting flux from phospholipid synthesis to MCFA production. Our results show that induced protein degradation can be used to dynamically alter metabolic flux, and thereby increase the yield of a desired compound. The strategy reported herein should be widely useful in a range of metabolic engineering applications in which essential enzymes divert flux away from a desired product, as well as in the production of polyketides, bioplastics, and other recursively synthesized hydrocarbons for which chain-length control is desired.

  16. Tailored fatty acid synthesis via dynamic control of fatty acid elongation.

    Science.gov (United States)

    Torella, Joseph P; Ford, Tyler J; Kim, Scott N; Chen, Amanda M; Way, Jeffrey C; Silver, Pamela A

    2013-07-01

    Medium-chain fatty acids (MCFAs, 4-12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even- and odd-chain-length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, thereby slowing acyl-ACP elongation and redirecting flux from phospholipid synthesis to MCFA production. Our results show that induced protein degradation can be used to dynamically alter metabolic flux, and thereby increase the yield of a desired compound. The strategy reported herein should be widely useful in a range of metabolic engineering applications in which essential enzymes divert flux away from a desired product, as well as in the production of polyketides, bioplastics, and other recursively synthesized hydrocarbons for which chain-length control is desired. PMID:23798438

  17. 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.

  18. 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.

  19. 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

  20. 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

  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. 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 ...

  3. Fullerene-derivatized amino acids: synthesis, characterization, antioxidant properties, and solid-phase peptide synthesis.

    Science.gov (United States)

    Yang, Jianzhong; Alemany, Lawrence B; Driver, Jonathan; Hartgerink, Jeffrey D; Barron, Andrew R

    2007-01-01

    A series of [60]fullerene-substituted phenylalanine (Baa) and lysine derivatives have been prepared by the condensation of 1,2-(4'-oxocyclohexano)fullerene with the appropriately protected (4-amino)phenylalanine and lysine, respectively. Conversion of the imine to the corresponding amine is achieved by di-acid catalyzed hydroboration. The reduction of the imine is not accompanied by hydroboration of the fullerene cage. The [70]fullerene phenylalanine derivative has also been prepared as have the di-amino acid derivatives. The compounds were characterized by MALDI-TOF mass spectrometry, UV/Vis spectroscopy, and cyclic voltammetry. 1H and 13C NMR spectroscopy allowed the observation of diastereomers. Fullerene-substituted peptides may be synthesized on relatively large scale by solid-phase peptide synthesis. The presence of the C60-substituted amino acid in a peptide has a significant effect on the secondary structures and self-assembly properties of peptides as compared to the native peptide. The antioxidant assay of Baa and a Baa-derived anionic peptide was determined to be significantly more potent than Trolox. PMID:17236230

  4. 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...

  5. 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...

  6. 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

  7. Effect of fatty acids on the synthesis and secretion of apolipoprotein B by rat hepatocytes

    International Nuclear Information System (INIS)

    The modulation of apolipoprotein B synthesis and secretion by fatty acids in rat hepatocytes was studied. Maximum apolipoprotein B production was obtained in the case of oleic acid followed by linoleic, stearic and palmitic/linolenic acid when compared to control which was not supplemented with any fatty acids. Oleic acid was found to exert a concentration dependent increase in the secretion of [3H] apolipoprotein B into the medium while that associated with the cell layer was not affected. Pulse chase experiments in the presence of oleic acid showed that it caused an increase in the secretion of apolipoprotein B into the medium. 14C-acetate incorporation into cholesterol and cholesteryl ester associated with the cell layer and secreted very low density lipoproteins also showed an increase in the presence of oleic acid indicating an increase in cholesterogenesis. The effect of oleic acid on [3H] apolipoprotein B and very low density lipoprotein secretion appeared to be mediated through cholesterol as (i)ketoconazole, an inhibitor of cholesterol synthesis caused significant reduction in the stimulatory effect of oleic acid on apolipoprotein secretion and (ii) mevinolin, another inhibitor of cholesterol synthesis also reversed the stimulatory effect of oleic acid on apolipoprotein B secretion. These results indicated that oleic acid may influence apolipoprotein B synthesis and secretion in hepatocytes probably by affecting cholesterol/cholesteryl ester formation which may be a critical component in the secretion of apolipoprotein B as lipoproteins. (author). 21 refs., 4 figs., 2 tabs

  8. 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

  9. 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.

  10. 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

  11. 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 ...

  12. 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.

  13. 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.

  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. 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...

  18. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Hugenberg, S.T.; Myers, S.L.; Brandt, K.D.

    1989-04-01

    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.

  20. 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

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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,...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

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

    Science.gov (United States)

    2013-08-07

    ... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary... conducting an administrative review under the countervailing duty (CVD) order on polyethylene terephthalate... polyethylene terephthalate film, sheet and strip, whether extruded or coextruded. Excluded are metallized...

  20. 21 CFR 870.3470 - Intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or...

    Science.gov (United States)

    2010-04-01

    ... polypropylene, polyethylene terephthalate, or polytetrafluoroethylene. 870.3470 Section 870.3470 Food and Drugs... polypropylene, polyethylene terephthalate, or polytetrafluoroethylene. (a) Identification. An intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene is a...

  1. Characterization of a novel N-acetylneuraminic acid lyase favoring N-acetylneuraminic acid synthesis.

    Science.gov (United States)

    Ji, Wenyan; Sun, Wujin; Feng, Jinmei; Song, Tianshun; Zhang, Dalu; Ouyang, Pingkai; Gu, Zhen; Xie, Jingjing

    2015-01-01

    N-Acetylneuraminic acid lyase (NAL, E.C. number 4.1.3.3) is a Class I aldolase that catalyzes the reversible aldol cleavage of N-acetylneuraminic acid (Neu5Ac) from pyruvate and N-acetyl-D-mannosamine (ManNAc). Due to the equilibrium favoring Neu5Ac cleavage, the enzyme catalyzes the rate-limiting step of two biocatalytic reactions producing Neu5Ac in industry. We report the biochemical characterization of a novel NAL from a "GRAS" (General recognized as safe) strain C. glutamicum ATCC 13032 (CgNal). Compared to all previously reported NALs, CgNal exhibited the lowest kcat/Km value for Neu5Ac and highest kcat/Km values for ManNAc and pyruvate, which makes CgNal favor Neu5Ac synthesis the most. The recombinant CgNal reached the highest expression level (480 mg/L culture), and the highest reported yield of Neu5Ac was achieved (194 g/L, 0.63 M). All these unique properties make CgNal a promising biocatalyst for industrial Neu5Ac biosynthesis. Additionally, although showing the best Neu5Ac synthesis activity among the NAL family, CgNal is more related to dihydrodipicolinate synthase (DHDPS) by phylogenetic analysis. The activities of CgNal towards both NAL's and DHDPS' substrates are fairly high, which indicates CgNal a bi-functional enzyme. The sequence analysis suggests that CgNal might have adopted a unique set of residues for substrates recognition. PMID:25799411

  2. 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.

  3. Synthesis and Characterization of Esters Derived from Ricinoleic Acid and Evaluation of their Low Temperature Property

    International Nuclear Information System (INIS)

    A series of ester compounds derived from ricinoleic acid to be used as bio lubricants base stock have been synthesized. The resulting products were confirmed by FTIR and NMR analyses. The synthesis was carried out in three stages: epoxidation of ricinoleic acid; synthesis of 10,12-dihydroxy-9-acyloxy stearic acid from epoxidized ricinoleic acid with various fatty acids and esterification of the acyloxy stearic acid products with octanol to yield octyl-10,12-dihydroxy-9-acyloxy stearate. The viscosities, flash points and pour points (PP) behavior of the products were measured. The resulting esters had an increased in molar weight and viscosity and decreased in pour points as compared to ricinoleic acid. (author)

  4. 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.

  5. 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 ...

  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. 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.

  8. 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.

  9. 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.

  10. 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.

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

    DEFF Research Database (Denmark)

    Nandurkar, Nitin Subhash; Petersen, Rico; Qvortrup, Katrine; Komnatnyy, Vitaly V.; Taveras, Kennedy; Le Quement, Sebastian Thordal; Frauenlob, Robin; Givskov, Michael; Nielsen, Thomas Eiland

    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...... and heteroaromatics, ultimately affording hydroxamic acid derivatives in high purities....

  12. 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)

  13. Exogenous fatty acids affect CDP-choline pathway to increase phosphatidylcholine synthesis in granular pneumocytes

    International Nuclear Information System (INIS)

    Regulation of phosphatidylcholine (PC) synthesis in rat granular pneumocytes isolated by tryptic digestion of lungs and maintained in primary culture for 24 h was investigated by following effects of exogenous fatty acids on [3H-methyl]choline incorporation into PC and disaturated PC (DSPC). At 0.1 mM choline, the rate of choline incorporation into PC and DSPC was 440 +/- and 380 +/- 50 pmol/h/ug Pi (mean +/- SE, n=3-5), respectively, and was linear for up to 3 h. PC synthesis was significantly increased by 0.1 mM each of palmitic, oleic, linoleic, or linolenic acid. However, synthesis of DSPC was increased only by palmitic acid and this increase was prevented by addition of oleic acid suggesting lack of effect on the remodeling pathway. Pulse-chase experiments with choline in absence or presence of palmitic or oleic acid showed that the label declined in choline phosphate and increased in PC more rapidly in presence of either of the fatty acids, suggesting rapid conversion of choline phosphate to PC. Microsomal choline phosphate cytidyltransferase activity in cells preincubated without or with palmitic acid for 3 h was 0.81 +/- 0.07 and 1.81 +/- 0.09 nmol choline phosphate converted/min/mg protein (n=4). These results suggest that in granular pneumocytes, exogenous fatty acids modulate PC synthesis by increasing choline phosphate cytidyltransferase activity

  14. 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...

  15. 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.

  16. 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.

  17. A new synthesis of double labeled [7,9-13C2] folic acid

    International Nuclear Information System (INIS)

    A convenient small scale chemical synthesis of double labeled folic acid with 13C at positions C-7 and C-9 is reported. [1,3-13C2] acetone was converted into folic acid in two steps, with [1, 1, 3]-trichloroacetone as the labeled intermediate. (Author)

  18. Potency of Individual Bile Acids to Regulate Bile Acid Synthesis and Transport Genes in Primary Human Hepatocyte Cultures

    Science.gov (United States)

    Liu, Jie; Lu, Hong; Lu, Yuan-Fu; Lei, Xiaohong; Cui, Julia Yue; Ellis, Ewa; Strom, Stephen C.; Klaassen, Curtis D.

    2014-01-01

    Bile acids (BAs) are known to regulate their own homeostasis, but the potency of individual bile acids is not known. This study examined the effects of cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA) on expression of BA synthesis and transport genes in human primary hepatocyte cultures. Hepatocytes were treated with the individual BAs at 10, 30, and 100?M for 48 h, and RNA was extracted for real-time PCR analysis. For the classic pathway of BA synthesis, BAs except for UDCA markedly suppressed CYP7A1 (70–95%), the rate-limiting enzyme of bile acid synthesis, but only moderately (35%) down-regulated CYP8B1 at a high concentration of 100?M. BAs had minimal effects on mRNA of two enzymes of the alternative pathway of BA synthesis, namely CYP27A1 and CYP7B1. BAs increased the two major target genes of the farnesoid X receptor (FXR), namely the small heterodimer partner (SHP) by fourfold, and markedly induced fibroblast growth factor 19 (FGF19) over 100-fold. The BA uptake transporter Na+-taurocholate co-transporting polypeptide was unaffected, whereas the efflux transporter bile salt export pump was increased 15-fold and OST?/? were increased 10–100-fold by BAs. The expression of the organic anion transporting polypeptide 1B3 (OATP1B3; sixfold), ATP-binding cassette (ABC) transporter G5 (ABCG5; sixfold), multidrug associated protein-2 (MRP2; twofold), and MRP3 (threefold) were also increased, albeit to lesser degrees. In general, CDCA was the most potent and effective BA in regulating these genes important for BA homeostasis, whereas DCA and CA were intermediate, LCA the least, and UDCA ineffective. PMID:25055961

  19. Impaired negative feedback suppression of bile acid synthesis in mice lacking βKlotho

    OpenAIRE

    ITO, SHINJI; Fujimori, Toshihiko; Furuya, Akiko; Satoh, Junko; Nabeshima, Yoko; NABESHIMA, YO-ICHI

    2005-01-01

    We have generated a line of mutant mouse that lacks βKlotho, a protein that structurally resembles Klotho. The synthesis and excretion of bile acids were found to be dramatically elevated in these mutants, and the expression of 2 key bile acid synthase genes, cholesterol 7α-hydroxylase (Cyp7a1) and sterol 12α-hydroxylase (Cyp8b1), was strongly upregulated. Nuclear receptor pathways and the enterohepatic circulation, which regulates bile acid synthesis, seemed to be largely intact; however, bi...

  20. Synthesis of zirconium carbide nanosized powders by pursed wire discharge in oleic acid

    Science.gov (United States)

    Sugashima, Kenta; Suzuki, Kazuma; Suzuki, Tsuneo; Nakayama, Tadachika; Suematsu, Hisayuki; Niihara, Koichi

    2016-01-01

    In this study, we propose novel PWD methods in inert gas mixed organic vapor and organic liquid which work as harmless carbon sources. Metal zirconium wire evaporation by PWD in organic vapor or liquid media was investigated. It was confirmed that in the PWD process using oleic acid liquid, single phase zirconium carbide nanopowders were synthesized by a reaction between Zr vapor and oleic acid. A new method for synthesis of carbide nanopowders was developed using the PWD in organic liquid. Therefore, the present result suggested that PWD method in oleic acid liquids is effective for the synthesis of carbide nanopowders.

  1. 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.)

  2. Synthesis, binding affinity at glutamic acid receptors, neuroprotective effects, and molecular modeling investigation of novel dihydroisoxazole amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Grazioso, Giovanni; Roda, Gabriella; Pinto, Andrea; Hansen, Kasper Bø; Nielsen, Birgitte; Madsen, Ulf; Bräuner-Osborne, Hans; Egebjerg, Jan; Vestri, Valentina; Pellegrini-Giampietro, Domenico E; Sibille, Pauline; Acher, Francine C; De Micheli, Carlo

    2005-01-01

    The four stereoisomers of 5-(2-amino-2-carboxyethyl)-4,5-dihydroisoxazole-3-carboxylic acid(+)-4, (-)-4, (+)-5, and (-)-5 were prepared by stereoselective synthesis of two pairs of enantiomers, which were subsequently resolved by enzymatic procedures. These four stereoisomers and the four stereoi...

  3. 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.

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

    International Nuclear Information System (INIS)

    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

  5. 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...

  6. Synthesis and tissue biodistribution of [?-11C]palmitic acid. A novel PET imagining agent for cardiac fatty acid metabolism

    International Nuclear Information System (INIS)

    In order to diagnose patients with medium-chain acyl-CoA dehydrogenase deficiency with a noninvasive diagnostic technique such as positron emission tomography, they have developed a synthesis of [?-11C]palmitic acid. The radiochemical synthesis was achieved by coupling an alkylfuran Grignard reagent (7) with [11C]methyl iodide, followed by rapid oxidative cleavage of the furan ring to the carboxylate using ruthenium tetraoxide. Tissue biodistribution studies in rags comparing [?-11C]palmitic acid and [1-11C]palmitic acid show that the %ID/g and %ID/organ in the heart tissue after administration of [?-11C]palmitic acid is approximately 50% greater than after administration of [1-11C]palmitic acid, due to the diminished metabolism of the [?-11C]palmitic acid. These studies show as well, low uptake in nontarget tissues (blood, lung, kidney, and muscle). PET images of a dog heart obtained after administration of [?-11C]- and [1-11C]palmitic acid show virtually identical uptake and distribution in the myocardium. The differing cardiac washout of labeled palmitates measured by dynamic PET studies may allow diagnosis of disorders in cardiac fatty acid metabolism

  7. 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.

  8. Synthesis and structural analysis of 13C-fatty acids

    International Nuclear Information System (INIS)

    The 13C-labelled fatty acids octanoic-1-13C acid and palmitic-1-13C acid were synthetically prepared from Ba 13CO3. The yield of the former was more than 90% and that of the latter was above 85%. MS, IR, 1H-NMR and 13NMR were performed to analyze the structures of the two 13C-fatty acids, compared with their unlabelled fatty acids

  9. 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...

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

    Science.gov (United States)

    ... disease (cirrhosis). The spleen may also become enlarged (splenomegaly). The inability to absorb certain fat-soluble vitamins ( ... inherited ; intestine ; jaundice ; oxidoreductase ; prevalence ; recessive ; rickets ; soluble ; splenomegaly ; steatorrhea ; synthesis ; vitamins You may find definitions for ...

  11. 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.

  12. 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...

  13. Synthesis of 18F-FDG using improved single-pot acid hydrolysis process

    International Nuclear Information System (INIS)

    In order to explore an optimum condition to increase the synthesis yield of 2-18F-2-deoxy-?-D-glucose (18F-FDG) by using improved single-pot acid hydrolysis Chemistry Process Control Unit (CPCU), various production conditions such as the reaction temperature, the time of acid hydrolysis and others were tested. The results showed that the determinant factor which affects the synthesis yield was the quantities of water present in reaction media. The total 18F-FDG synthesis time could be minimized by effective dehydration step and regulating the amount of hydrogen chloride. The synthesis yield could be increased by improving the production conditions of 18F-FDG. (authors)

  14. 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

  15. 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)

  16. 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...

  17. Synthesis and characterization of copolymer hydrogels of chitosan, itaconic acid and N-isopropilacrylamide

    OpenAIRE

    Milosavljevi? Nedeljko B.; Milašinovi? Nikola Z.; Filipovi? Jovanka M.; Kalagasidis-Kruši? Melina T.

    2011-01-01

    This paper deals with synthesis of copolymer hydrogels of N-isopropilacrylamide, itaconic acid and chitosan. During synthesis, pH of the reaction solution and temperature were varied. It was found that reaction at higher temperature, above lower critical solution temperature (LCST) value of N-isopropilacrylamide resulted in a formation of polymer rich domains or aggregates in the matrix of loosely tied network, which cause a higher degree of swelling. Moreover, reaction pH also affects ...

  18. 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...

  19. 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

  20. Inhibitors of Fatty Acid Synthesis Induce PPAR ? -Regulated Fatty Acid ? -Oxidative Genes: Synergistic Roles of L-FABP and Glucose.

    Science.gov (United States)

    Huang, Huan; McIntosh, Avery L; Martin, Gregory G; Petrescu, Anca D; Landrock, Kerstin K; Landrock, Danilo; Kier, Ann B; Schroeder, Friedhelm

    2013-01-01

    While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor- ? (PPAR ? ) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20?mM) but not physiological (6?mM) glucose conferred on both TOFA and C75 the ability to induce PPAR ? transcription of the fatty acid ? -oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPAR ? in the context of high glucose at levels similar to those in uncontrolled diabetes. PMID:23533380

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Peptide nucleic acids: structure, properties, applications, strategies and practice of chemical synthesis

    International Nuclear Information System (INIS)

    The information on the structure and properties of peptide nucleic acids (PNA) is generalised. The use of PNA oligomers in biomolecular studies and biotechnology is exemplified. The published data on the most important methods for the chemical synthesis of PNA oligomers with the main emphasis on the efficiency of condensation reactions are considered. The methods for PNA synthesis are systematised; their advantages and disadvantages are discussed. Some recommendations for optimisation of the condensation procedure and synthesis of PNA are presented. The bibliography includes 153 references.

  6. 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

  7. Orthogonally Protected Furanoid Sugar Diamino Acids for Solid-Phase Synthesis of Oligosaccharide Mimetics.

    Science.gov (United States)

    John, Franklin; Wittmann, Valentin

    2015-08-01

    Sugar diamino acids (SDAs), which differ from the widely used sugar amino acids in the presence of a second amino group connected to the carbohydrate core, share structural features of both amino acids and carbohydrates. They can be used for the preparation of linear and branched amide-linked oligosaccharide mimetics. Such oligomers carry free amino groups, which are positively charged at neutral pH, in a spatially defined way and, thus, represent a potential class of aminoglycoside mimetics. We report here the first examples of orthogonally protected furanoid SDAs and their use in solid-phase synthesis. Starting from d-glucose, we developed a divergent synthetic route to three derivatives of 3,5-diamino-3,5-dideoxy-d-ribofuranose. These building blocks are compatible with solid-phase peptide synthesis following the 9-fluorenylmethoxycarbonyl (Fmoc) strategy, which we demonstrate by the synthesis of an SDA tetramer. PMID:26161849

  8. Aqueous Microwave-Assisted Solid-Phase Synthesis Using Boc-Amino Acid Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yoshinobu Fukumori

    2013-07-01

    Full Text Available We have previously developed water-based microwave (MW-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of nanoparticle reactants on the resin in water. We also demonstrated the syntheses of Leu-enkephalin, Tyr-Gly-Gly-Phe-Leu-OH, and difficult sequence model peptide, Val-Ala-Val-Ala-Gly-OH, using our water-based MW-assisted protocol with Boc-amino acid nanoparticles.

  9. 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

  10. 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 ...

  11. 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.

  12. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

    Science.gov (United States)

    Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

    2011-01-01

    A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

  13. 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.

  14. Effect of retinoic acid on melanoma cell-derived factor stimulation of fibroblast glycosaminoglycan synthesis.

    Science.gov (United States)

    Edward, M; Godden, J L; Alexander, C L; MacKie, R M

    1997-06-01

    The hyaluronan-rich matrix that surrounds many tumours and facilitates tumour cell growth and invasion is thought to be predominantly synthesized by normal stromal cells stimulated by tumour cell-derived factors. This study examines the possibility that the production of tumour cell-derived factors that stimulate fibroblast glycosaminoglycan (GAG) synthesis may be blocked by exposure to differentiation-inducing agents such as retinoic acid. We have demonstrated that Hs294T, C8161 and A375 human melanoma cell lines release factors into their medium that stimulate normal fibroblast GAG synthesis. Exposure of these melanoma cells to retinoic acid failed to mediate any significant reduction in growth over a 7-day period. Retinoic acid failed to block the tumour cell production of GAG-stimulating activities and even enhanced the activities produced by the C8161 cell line, particularly at low retinoic acid concentrations (48% stimulation at 10(-9) M retinoic acid; P < 0.02). Addition of retinoic acid directly to fibroblast cultures exposed to fibroblast-conditioned medium resulted in an inhibition of GAG synthesis with a 33% inhibition observed at 10(-5) M. Addition of retinoic acid to fibroblast cultures exposed to the tumour cell-conditioned medium failed to inhibit the stimulation of GAG synthesis. Other differentiation-inducing agents, such as hexamethylene-bis-acetamide and butyrate, also failed to block the production of tumour cell-derived GAG-stimulating activities. These results demonstrate that retinoic acid and other differentiation-inducing agents fail to inhibit melanoma cell production of fibroblast GAG synthesis-stimulating factors or their action upon fibroblasts. PMID:9195557

  15. 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.

  16. 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.

  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 μm.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Regulation of nucleic acid synthesis in Artemia salina nauplii by environmental salinity.

    Science.gov (United States)

    Ewing, R D; Conte, F P; Peterson, G L

    1980-01-01

    Ribonucleic acid synthesis in Artemia salina nauplii was strongly inhibited by increasing salinity in the surrounding media, as measured by incorporation of tritiated uridine. Although precursor pools varied in both concentration and specific activity with increasing salinity, these changes did not account for the reduction in ribonucleic acid synthesis. Low levels of oxygen at high salt concentrations did not account for this effect. Intracellular ATP concentrations decreased as the salinity of the environment was increased. Levels of ATP were not affected either by increased oxygen or by the presence of ouabain in the medium. PMID:7356052

  3. Synthesis of glycosyl-amino acids of biological interest; Sintese de glicoaminoacidos de interesse biologico

    Energy Technology Data Exchange (ETDEWEB)

    Campo, Vanessa Leiria; Carvalho, Ivone [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: carronal@usp.br

    2008-07-01

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

  4. 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...

  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. 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

  7. Amino acids augment muscle protein synthesis in neonatal pigs during acute endotoxemia by stimulating mTOR-dependent translation initiation

    Science.gov (United States)

    In skeletal muscle of adults, sepsis reduces protein synthesis by depressing translation initiation and induces resistance to branched-chain amino acid stimulation. Normal neonates maintain a high basal muscle protein synthesis rate that is sensitive to amino acid stimulation. In the present study...

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

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Bertel, Linda; Páez-Mozo, Edgar; Martínez, Fernando

    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...... 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...

  9. Synthesis of ( sup 14 CO)ellagic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wenguang Zeng; Heur, Y.-H.; Stoner, G.D. (Medical Coll. of Ohio, Toledo, OH (United States)); Kinstle, T.H. (Bowling Green State Univ., OH (United States))

    1991-06-01

    ({sup 14}CO)Ellagic acid with a chemical purity of 98.9% and radiochemical purity of 99.9% was synthesized with an overall yield of 16% (both chemically and radiochemically). Reaction of {sup 14}CO{sub 2} with lithiated 3,4,5-trimethoxybenzene and demethylation of the resulting 3,4,5-trimethoxybenzoic acid was followed by esterification and coupling of methyl gallate into ellagic acid. Two efficient coupling methods were employed: direct aeration and aeration of methyl gallate in the presence of the phenolic oxidase, tyrosinase. The latter method produced the highest yield and purity. This preparation produced ({sup 14}CO)ellagic acid with a specific activity of 20 mCi/mmol. The yields of labeled 3,4,5-trimethoxybenzoic acid and ellagic acid based on Ba{sup 14}CO{sub 3} were 65% and 16%, respectively. (author).

  10. Synthesis, acid properties and catalysis by niobium oxide nanostructured materials

    OpenAIRE

    Marín García, Mª Luisa; Hallett-Tapley, Geniece L.; Impellizzeri, Stefania; Fasciani, Chiara; Simoncelli, Sabrina; Netto-Ferreira, Jose Carlos; Scaiano, Juan C.

    2014-01-01

    Several forms of niobium oxide were prepared, including nanostructured mesoporous materials, and their acidity properties were comprehensively investigated and compared with commercially available materials. The composites were characterized by a variety of techniques, including XRD, TEM, N-2 adsorption and Hammett acid indicator studies. The acidity of the niobium oxide derivatives was also investigated by the ability of the materials to successfully promote the halochromic ring-opening of a...

  11. 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...

  12. Synthesis and Characterization of Poly(glyceric Acid Carbonate): A Degradable Analogue of Poly(acrylic Acid).

    Science.gov (United States)

    Zhang, Heng; Lin, Xinrong; Chin, Stacy; Grinstaff, Mark W

    2015-10-01

    The synthesis and characterization of a degradable version of poly(acrylic acid), poly(glyceric acid carbonate), are reported. Specifically, atactic and isotactic poly(benzyl glycidate carbonate)s are obtained via the ring-opening copolymerization of rac-/(R)-benzyl glycidate with CO2 using a bifunctional rac-/(S,S)-cobalt salen catalyst in high carbonate linkage selectivity (>99%) and polymer/cyclic carbonate selectivity (∼90%). Atactic poly(benzyl glycidate carbonate) is an amorphous material with a T(g) (glass transition temperature) of 44 °C, while its isotactic counterpart synthesized from enantiopure epoxide and catalyst is semicrystalline with a T(m) (melting temperature) = 87 °C. Hydrogenolysis of the resultant polymers affords the poly(glyceric acid carbonate). Poly(glyceric acid carbonate) exhibits an improved cell cytotoxicity profile compared to poly(acrylic acid). Poly(glyceric acid carbonate)s also degrade remarkably fast (t(1/2) ≈ 2 weeks) compared to poly(acrylic acid). Cross-linked hydrogels prepared from poly(glyceric acid carbonate) and poly(ethylene glycol) diaziridine show significant degradation in pH 8.4 aqueous buffer solution compared to similarly prepared hydrogels from poly(acrylic acid) and poly(ethylene glycol) diaziridine. PMID:26378624

  13. 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

  14. 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.

  15. 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)

  16. Polymers from fatty acids: poly(ω-hydroxyl tetradecanoic acid) synthesis and physico-mechanical studies.

    Science.gov (United States)

    Liu, Chen; Liu, Fei; Cai, Jiali; Xie, Wenchun; Long, Timothy E; Turner, S Richard; Lyons, Alan; Gross, Richard A

    2011-09-12

    This Article describes the synthesis and physicomechanical properties of bioplastics prepared from methyl ω-hydroxytetradecanoic acid (Me-ω-OHC14), a new monomer available by a fermentation process using an engineered Candida tropicalis strain. Melt-condensation experiments were conducted using titanium tetraisopropoxide (Ti[OiPr](4)) as a catalyst in a two-stage polymerization (2 h at 200 °C under N(2), 4 h at 220 °C under 0.1 mmHg). Poly(ω-hydroxytetradecanoate), P(ω-OHC14), M(w), determined by SEC-MALLS, increased from 53K to 110K as the Ti(OiPr)(4) concentration increased from 50 to 300 ppm. By varying the polymerization conditions (catalyst concentration, reaction time, second-stage reaction temperature) a series of P(ω-OHC14) samples were prepared with M(w) values from 53K to 140K. The synthesized polyesters with M(w) ranging from 53K to 140K were subjected to characterization by DSC, TGA, DMTA, and tensile testing. Influences of P(ω-OHC14) molecular weight, melting point, and enthalpies of melting/crystallization on material tensile properties were explored. Cold-drawing tensile tests at room temperature for P(ω-OHC14) with M(w) 53K-78K showed a brittle-to-ductile transition. In contrast, P(ω-OHC14) with M(w) 53K undergoes brittle fracture. Increasing P(ω-OHC14) M(w) above 78K resulted in a strain-hardening phenomena and tough properties with elongation at break ~700% and true tensile strength of ~50 MPa. Comparisons between high density polyethylene and P(ω-OHC14) mechanical and thermal properties as a function of their respective molecular weights are discussed. PMID:21793591

  17. 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...

  18. Phenazines and natural products; novel synthesis of saphenic acid

    DEFF Research Database (Denmark)

    Petersen, Lars; Jensen, Knud J.; Nielsen, John

    The natural product saphenic acid (6-(1-hydroxyethyl)1- phenazinecarboxylic acid) was synthesized from readily accessible starting materials. The desired product was obtained in an overall yield of 22% for four steps with the key steps being formation of a diphenylamine, followed by cyclization...

  19. Phenazines and natural products; Novel synthesis of saphenic acid

    DEFF Research Database (Denmark)

    Petersen, Lars; Jensen, Knud Jørgen; Nielsen, John

    The natural product saphenic acid (6-(1-hydroxyethyl)1-phenazinecarboxylic acid) was synthesized from readily accessible starting materials. The desired product was obtained in an overall yield of 22% for four steps with the key steps being formation of a diphenylamine, followed by cyclization...

  20. 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 ...

  1. 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...

  2. Synthesis of triallylmethane based on the reactions of triallylborane with carbonic acid derivatives

    International Nuclear Information System (INIS)

    The reactions of triallylborane with carbonic acid derivatives (ethylene carbonate, diethylcyanoamide, and O,S-dimethyl-dithio carbonate) have been studied for the purpose of preparation of hydroxy-, amino-, and thio derivatives of triallylmethane. An original method for the synthesis of the triallylmethane functional derivatives based on the reactions of triallylborane with the above-mentioned carbonic acid derivatives at 110-120 deg C has been developed. 23 refs.; 1 tab

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

    OpenAIRE

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

    2015-01-01

    Solid-phase synthesis of purine derivatives bearing an alpha-amino acid motif in position 9 is described herein. Polymer supported amines were acylated with various Fmoc-alpha-amino acids and, after cleavage of the protecting group, arylation with 4,6-dichloro-5-nitropyrimidine or 2,4-dichloro-5-nitropyrimidine was performed. The second chlorine atom was replaced with various amines. Subsequent reduction of the nitro group, followed by reaction with aldehydes, afforded the purine scaffold. Af...

  4. Synthesis, Characterization and In Vitro Anticancer Evaluation of Itaconic Acid Based Random Copolyester

    OpenAIRE

    J. Gowsika; R. Nanthini

    2014-01-01

    The present study deals with the synthesis and characterization of an aliphatic copolyester, poly [butylene fumarate-co-butylene itaconate] (PIFB) copolymer was obtained from itaconic acid, fumaric acid, and 1,4-butanediol using titanium tetraisopropoxide (TTiPO) through a two step process of transesterification and melt polycondensation. The synthesized aliphatic random copolyester was characterized with the help of FT-IR, 1H-NMR, 13C-NMR, viscosity measurements, Gel Permeation Chromatograph...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. Synthesis and reactivity of alpha-trialkylsilyl alpha-amino acids

    OpenAIRE

    Veri, Elisabetta

    2006-01-01

    This work deals with the synthesis and reactivity of alpha-trialkylsilyl alpha-amino acids. They were synthesised using an established protocol involving rhodium(II)-catalysed insertion reactions of alpha-trialkylsilyl alpha-diazo esters into N-H bonds of carbamates. As an extension to this procedure, it was accounted that a diastereoselective approach to N-protected alpha-trialkylsilyl alpha-amino acids precursors may lead, after deprotection, to the formation of enantiomerically-pure alpha-...

  10. 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.

  11. 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

  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. (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

  15. 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.

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

    International Nuclear Information System (INIS)

    Highlights: â–º An easy method for synthesis of graphene sheets using alfalfa plants was introduced. â–º An novelty formation mechanism of graphene sheets using alfalfa plants was proposed. â–º 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

  17. Synthesis and pharmacology of 3-hydroxy-delta2-isoxazoline-cyclopentane analogues of glutamic acid

    DEFF Research Database (Denmark)

    Conti, P; De Amici, M; Bräuner-Osborne, Hans; Madsen, U; Toma, L; De Micheli, C

    2002-01-01

    The synthesis and pharmacology of two potential glutamic acid receptor ligands are described. Preparation of the bicyclic 3-hydroxy-delta2-isoxazoline-cyclopentane derivatives (+/-)-7 and (+/-)-8 was accomplished via 1,3-dipolar cycloaddition of bromonitrile oxide to suitably protected 1-amino-cy...

  18. 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

  19. Methods for the synthesis of tritium-labelled fatty acids and their derivatives, oxylipins and steroids

    International Nuclear Information System (INIS)

    The achievements in the field of synthesis and application of tritium-labelled oxylipins, steroids, fatty acids, phospho-, sphingo- and other lipids are reviewed. The importance of these studies for the solution of current problems of biochemistry, biology and pharmacology is exemplified in the application of labelled compounds. The bibliography includes 148 references.

  20. (Het)aroylpyruvic acids and their derivatives as promising building blocks for organic synthesis

    International Nuclear Information System (INIS)

    Methods of synthesis of (het)aroylpyruvic acids and their acyclic derivatives (esters, amides and hydrazides), and their reactions with various C-, N-, O-, S-nucleophiles are described. Problems of tautomerism and biological activity of (het)aroylpyruvates and products of their transformation are briefly considered. The bibliography includes 191 references.

  1. Fluorine-containing 2,4-dioxo acids in the synthesis of heterocyclic compounds

    International Nuclear Information System (INIS)

    The review surveys the data on the synthesis, tautomerism, electronic structures and chemical transformations of 4-polyfluoroalkyl- and 4-pentafluorophenyl-2,4-dioxo acids and their derivatives. The reactions yielding fluorinated heterocyclic compounds and their further conversions are considered. The bibliography includes 86 references.

  2. Synthesis of mono-ADP-ribosylated oligopeptides using ribosylated amino acid building blocks.

    Science.gov (United States)

    van der Heden van Noort, Gerbrand J; van der Horst, Maarten G; Overkleeft, Herman S; van der Marel, Gijsbert A; Filippov, Dmitri V

    2010-04-14

    Adenosine diphosphate ribosylation (ADP-ribosylation) is a widely occurring post-translational modification of proteins at nucleophilic side chains of amino acid residues, such as asparagine, glutamic acid, and arginine. Elucidation of the biological role of ADP-ribosylation events would benefit from the availability of well-defined ADP-ribosylated peptides. Main issues in the construction of synthetic ADP-ribosylated peptides involve the availability of protected ribosylated amino acids suitable for peptide synthesis, development of a protective group strategy for peptide fragments compatible with the integrity of the adenosine diphosphate moiety, and an efficient procedure for pyrophosphate formation. In this paper we present a first approach to the chemical synthesis of ADP-ribosylated peptides in solution and on solid support. We describe an efficient synthesis of suitably protected ribosylated asparagine and glutamine building blocks suitable for Fmoc-based peptide synthesis. We further demonstrate a successful application of these ribosylated amino acids in the assembly of three fully synthetic ADP-ribosylated peptides by solution and solid phase approaches. PMID:20232863

  3. Synthesis and biological activity of some novel fluorenone-, 2- or 7-nitrofluorenone-1-carbonylamino acid derivatives

    OpenAIRE

    S. A. M. SHEDID; Hassan, H. M.

    1999-01-01

    The synthesis of fluorenone-, 2- or 7-nitrofluorenone-1-carbonylamino acid methyl ester and hydrazide derivatives IV-XXX is described. Many of the products were found to be active against a number of microorganisms. The spectral data of the synthesized compounds IV-XXX and the results of biological screening are briefly discussed.

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

    OpenAIRE

    Shitole Nana Vikram; Balasahe V. Shitole; Gopal K. Kakde; Shingare, Murlidhar S

    2013-01-01

    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.

  5. 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.

  6. Total synthesis of (±)-epithuriferic acid methyl ester via Diels-Alder reaction.

    Science.gov (United States)

    Koprowski, Marek; Bałczewski, Piotr; Owsianik, Krzysztof; Różycka-Sokołowska, Ewa; Marciniak, Bernard

    2016-01-27

    In this paper, we have described the first total synthesis of (±)-epithuriferic acid methyl ester from non-natural sources, in four steps (20% overall yield). The key step involves the Diels-Alder reaction of isobenzofuran with methyl 3-(dimethoxyphosphoryl)acrylate which is controlled by "ortho" regio- and endo stereoselectivities due to the COOMe group. PMID:26750755

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. 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)

  15. 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.

  16. 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.

  17. 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

  18. Synthesis and Physicochemial Properties of Three Glutaric Acid Diester

    Directory of Open Access Journals (Sweden)

    Salma Bte Samidin

    2016-01-01

    Full Text Available Abstract Three diesters were prepared through the esterification reaction of diacid (glutaric acid with 3 different straight chain alcohols with para-toluene sulphonic acid (PTSA (4% as a catalyst. The resulting products were confirmed by Fourier Transform Infrared (FTIR and Nuclear Magnetic Resonance (NMR analyses. The oxidative stability, viscosity, flash point and pour point were measured.  Dioctyl glutarate and didecyl glutarate showed a liquid form at room temperature. Glutaric acid diesters produced show high oxidative stability, higher than 187?C and high temperature pour point. Didodecyl glutarate forms solid at room temperature and shows high flash point of 210?C and viscosity index VI of 194 respectively. Keywords: Biolubricant, esterification, glutaric acid, alcohol

  19. 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...

  20. Synthesis of 1-11C-labeled fatty acid from [11C]HCN

    International Nuclear Information System (INIS)

    A new chemical approach to the preparation of [1-11C]fatty acids from [11C]HCN has been developed. Four straight chain [l-11C]fatty acids (C15-C18) and one branched chain [l-11C]fatty acid (3-methylheptadecanoic acid) were produced by the reaction of alkyl bromides with 11Cn- and subsequent hydrolysis. The synthesis time was 47-67 min after the end of bombardment, with radiochemical yields of 16-20 mCi (70-83%) for a series of straight chain [l-11C]fatty acids and 4-8 mCi (33-42%) for 3-methyl [l-11C]heptadecanoic acid (from 120 mCi of trapped [11C]HCN). This method has some advantages, such as no requirement of absolutely anhydrous solvent, easy 11C-labeling using an extremely small amount of substrate, and good reproducibility. (author)

  1. 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.

  2. 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 ...

  3. Double-helical nucleic acids with cross-linked strands: synthesis and applications in molecular biology

    International Nuclear Information System (INIS)

    Data on the methods employed for cross-linking of DNA strands and for the synthesis of oligonucleotide duplexes with cross-links between strands are summarised. Existing methods are systematised; their advantages and drawbacks are discussed. The examples of applications of DNA duplexes with covalently cross-linked chains for the study of protein-nucleic acid recognition and mechanisms of action of nucleic acid-binding proteins for gaining information about the spatial structure of nucleic acids, and for the solution of other problems of molecular biology are given. The bibliography includes 131 references.

  4. 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.

  5. 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

    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 dehydrogenation of acetaldehyde to acetic acid. The apparent reaction order was 0.89 with respect to water and...

  6. 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)

  7. 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

  8. Synthesis and properties of synthetic fulvic acid derived from hematoxylin

    Science.gov (United States)

    Litvin, Valentina A.; Minaev, Boris F.; Baryshnikov, Gleb V.

    2015-04-01

    A model fulvic acid (FA) was synthesized from a natural dye, hematoxylin, in a slow oxidative polymerization/condensation reaction catalysed by OH- at pH ca. 12. The resulting dark-brown product, acidified to pH ca. 2, did not precipitate from the reaction solution. It was isolated and purified by cation-exchange resin. Its physicochemical and spectroscopic properties, as determined by means of elemental analysis, molecular weight analyses, Fourier transform infra red (FTIR) and ultraviolet-visible (UV-VIS) spectroscopy, X-ray diffraction and electron paramagnetic resonance (EPR) spectroscopy, showed a close resemblance to natural FA. The similarity and differences between synthetic fulvic acids derived from hematoxylin and the natural fulvic acids substances are discussed. Quantum-chemical calculations of the supposed primary oxidation products of hematoxylin are performed and compared with observations.

  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. Synthesis of bis(2-chloroethyl)amides of polyhydroxy acids

    International Nuclear Information System (INIS)

    The bis(2-chloroethyl)amides of peracetylated L-arabonic, D-gluconic, and D-galactaric acids were synthesized. The acetyl protection in the obtained compounds is removed anomalously in alkaline media (ammonia, triethylamine, barium methoxide), but in acidic media (HCl) complete deacetylation occurs with the formation of the bis(2-chloroethyl)amides of the respective acids. The PMR spectra were obtained on a Tesla BS-497 spectrometer at 100 MHz in deuterochloroform with HMDS as internal standard. The chemical shifts are given with reference to TMS. The 13C NMR spectra were recorded on a Bruker WM-250 instrument at 62.89 MHz in deuterochloroform or heavy water with methanol as standard

  11. Synthesis of potential Schistosomicides: new 2-(alkylamino)-1-octometiosulfuric acids

    International Nuclear Information System (INIS)

    Four new 2-(alkylamino)-1-octanethiosulfuric acids (1) were synthesized from 1-octene. 1-Octene was epoxidized with MCPBA or with a two-phase system composed of H2O2, sodium tungstate, phosphoric acid, 1-octene and a phase transfer agent. Reaction of the 1,2-epoxyoetane with primary amines furnished 1-(alkylamino)-2octanols which were converted to the respective N-alkyl-2-bromo-1-octanamine hydrobromides by reaction with hydrobromic acid, followed by phosphorus tribromide. Finally, substitution of the bromide ion with sodium thiosulfate was accompanied by rearrangement via an aziridine intermediate, resulting in formation of the product. 1. The intermediates and the final products were screened for activity against infection by Schistosoma mansoni, only the final products in which the N-alkyl group was sec-butyl or isopropyl exhibited activity. Nuclear magnetic resonance and infrared and mass spectroscopy analysis are presented. (author)

  12. 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.

  13. Regulation of bile acid synthesis in humans: studies on cholesterol 7 alpha-hydroxylation in vivo.

    Science.gov (United States)

    Bertolotti, M; Abate, N; Loria, P; Concari, M; Guicciardi, M E; Dilengite, M A; Bozzoli, M; Carubbi, F; Carulli, N

    1995-01-01

    Over the last few years important progress has been made on the quantitation of cholesterol 7 alpha-hydroxylation, the rate-limiting step of bile acid synthesis. The use of a technique based on the determination of body water tritium enrichment after i.v. administration of [7 alpha-3H] cholesterol has allowed in vivo investigation of this step in humans in different experimental conditions. The cholesterol 7 alpha-hydroxylation rate was not affected by the administration of the hydrophilic bile acid ursodeoxycholic acid (UDCA) whereas it was significantly reduced by the more hydrophobic chenodeoxycholic acid (CDCA) and even more so by the strongly hydrophobic deoxycholic acid (DCA). The administration of cholestyramine induced a significant dose-related increase of 7 alpha-hydroxylation along with a correspondent decrease in plasma cholesterol. The administration of simvastatin exerted no effect on cholesterol 7 alpha-hydroxylation despite a marked decrease in serum cholesterol. Treatment with fibrates reduced plasma lipid levels and 7 alpha-hydroxylation rates. Hydroxylation rates were unchanged in familial hypercholesterolaemia and increased in familial combined hyperlipidaemia. These data suggest that in humans bile acid synthesis can be affected by quantitative and qualitative alterations of the enterohepatic circulation of bile acids. Changes in cholesterol 7 alpha-hydroxylation rates may be associated with alterations in plasma lipid levels, but such a relationship is ill-defined and seems to vary with the different experimental models. PMID:8775473

  14. 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.

  15. Synthesis and Quantitative Structure-Property Relationships of Side Chain-Modified Hyodeoxycholic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Antimo Gioiello

    2013-08-01

    Full Text Available Bile acids have emerged as versatile signalling compounds of a complex network of nuclear and membrane receptors regulating various endocrine and paracrine functions. The elucidation of the interconnection between the biological pathways under the bile acid control and manifestations of hepatic and metabolic diseases have extended the scope of this class of steroids for in vivo investigations. In this framework, the design and synthesis of novel biliary derivatives able to modulate a specific receptor requires a deep understanding of both structure-activity and structure-property relationships of bile acids. In this paper, we report the preparation and the critical micellization concentration evaluation of a series of hyodeoxycholic acid derivatives characterized by a diverse side chain length and by the presence of a methyl group at the alpha position with respect to the terminal carboxylic acid moiety. The data collected are instrumental to extend on a quantitative basis, the knowledge of the current structure-property relationships of bile acids and will be fruitful, in combination with models of receptor activity, to design and prioritize the synthesis of novel pharmacokinetically suitable ligands useful in the validation of bile acid-responsive receptors as therapeutic targets.

  16. 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

  17. 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.

  18. 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

  19. Synthesis of a diaminopropanoic acid-based nucleoamino acid and assembly of cationic nucleopeptides for biomedical applications.

    Science.gov (United States)

    Roviello, Giovanni N; Musumeci, Domenica; Bucci, Enrico M; Pedone, Carlo

    2012-12-01

    In this work, we report a synthetic approach to a Fmoc-protected nucleoamino acid, based on L-diaminopropanoic acid, carrying the DNA nucleobase on the alpha-amino group by means of an amide bond, suitable for the solid-phase synthesis of novel nucleopeptides of potential interest in biomedicine. After ESI-MS and NMR characterization this building block was used for the assembly of a thymine-functionalized nucleopeptide, composed of nucleobase-containing L-diaminopropanoic acid moieties and underivatized L-lysine residues alternated in the backbone. Circular dichroism studies performed on the cationic nucleopeptide and adenine-containing DNA and RNA molecules suggested that the thymine-containing peptide is able to interact with both DNA and RNA. In particular, a significant conformational variation in the RNA structure was suggested by CD studies. Human serum stability assays were also conducted on the cationic nucleopeptide, which was found to be highly resistant to enzymatic degradation. PMID:22688861

  20. Automated synthesis of {sup 11}C-acetoacetic acid, a key alternate brain fuel to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Sebastien [Research Center on Aging, Sherbrooke University Geriatric Institute, 1036 Belvedere Street South, Sherbrooke, Quebec, J1H 4C4 (Canada)]. E-mail: Sebastien.Tremblay@USherbrooke.ca; Ouellet, Rene [Sherbrooke Molecular Imaging Centre, Etienne-LeBel Clinical Research Centre, Centre Hospitalier Universitaire de Sherbrooke, Quebec, J1H 5N4 (Canada); Rodrigue, Serge [Sherbrooke Molecular Imaging Centre, Etienne-LeBel Clinical Research Centre, Centre Hospitalier Universitaire de Sherbrooke, Quebec, J1H 5N4 (Canada); Langlois, Rejean [Sherbrooke Molecular Imaging Centre, Etienne-LeBel Clinical Research Centre, Centre Hospitalier Universitaire de Sherbrooke, Quebec, J1H 5N4 (Canada); Department of Nuclear Medicine and Radiobiology, Quebec, J1H 5N4 (Canada); Benard, Francois [Sherbrooke Molecular Imaging Centre, Etienne-LeBel Clinical Research Centre, Centre Hospitalier Universitaire de Sherbrooke, Quebec, J1H 5N4 (Canada); Department of Nuclear Medicine and Radiobiology, Quebec, J1H 5N4 (Canada); Cunnane, Stephen C. [Research Center on Aging, Sherbrooke University Geriatric Institute, 1036 Belvedere Street South, Sherbrooke, Quebec, J1H 4C4 (Canada); Department of Medicine, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, Quebec, J1H 5N4 (Canada)

    2007-08-15

    An automated, one-pot radio-synthesis module for the routine preparation of 1-[{sup 11}C]acetoacetic acid has been developed. The enolate anion of acetone was reacted with [{sup 11}C]CO{sub 2} in tetrahydrofuran (THF), followed by hydrolysis and purification by ion-exchange chromatography. The total synthesis time was 18 min and radiochemical yield was 34% after decay correction. HPLC analysis showed {<=}3% impurities while residual THF ({<=}200 ppm) and ethanol ({<=}500 ppm) were well under the tolerable limits for human studies.

  1. 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.

  2. 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.

  3. Synthesis and phosphorylation of the glial fibrillary acidic protein during brain development: A tissue slice study

    Energy Technology Data Exchange (ETDEWEB)

    Noetzel, M.J. (Washington Univ. School of Medicine, St. Louis, MO (USA))

    1990-01-01

    Brain slices were incubated with either (3H) amino acids or (32P) orthophosphate in order to characterize the synthesis and phosphorylation of the glial fibrillary acidic protein (GFAP) in the rat nervous system. The incorporation of (3H) amino acids into GFAP was found to increase significantly during early postnatal development, reaching a peak of activity on day 5 of life and then declining over the next 2 weeks. Concomitant with this peak of synthetic activity the content of GFAP in rat brain was also observed to increase dramatically. GFAP continued to accumulate in brain through postnatal day 30 despite a decrease in the synthesis of the protein. These results indicate that the increase in GFAP during the first month of life cannot be ascribed solely to the rate of GFAP synthesis. The findings are consistent with the hypothesis that during later stages of astrocytic development the accumulation of GFAP may be primarily dependent upon a low rate of protein degradation. The pattern of GFAP phosphorylation in the developing rat brain differed from that observed for the incorporation of (3H) amino acids. The peak incorporation of 32P into GFAP occurred on postnatal day 10 at a time when synthesis of the protein had declined by 43%. These findings suggest that during development phosphorylation of GFAP is mediated by factors different from those directing its synthesis. In addition, phosphorylation of GFAP did not alter its solubility in cytoskeletal preparations indicating that GFAP phosphorylation is probably not a major regulatory mechanism in disassembly of the astroglial filaments.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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)

  11. 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

  12. 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

  13. 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.

  14. Aqueous Synthesis of Peptide Thioesters from Amino Acids and a Thiol Using 1,1?-Carbonyldiimidazole

    Science.gov (United States)

    Weber, Arthur L.

    2005-10-01

    A new method was developed for the synthesis of peptide thioesters from free amino acids and thiols in water. This one-pot simple method involves two steps: (1) activation in water of an amino acid presumably as its N-carboxyanhydride (NCA) using 1,1?-carbonyldiimidazole (CDI), and (2) subsequent condensation of the activated amino acid-NCA in the presence of a thiol. With this method citrulline peptide thioesters containing up to 10 amino acid residues were prepared in a single reaction. This aqueous synthetic method provides a simple way to prepare peptide thioesters for studies of peptide replication involving ligation of peptide thioesters on peptide templates. The relevance of peptide replication to the origin-of-life process is supported by previous studies showing that amino acid thioesters (peptide thioester precursors) can be synthesized under prebiotic conditions by reaction of small sugars with ammonia and a thiol.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. Fatty acid synthesis is inhibited by inefficient utilization of unusual fatty acids for glycerolipid assembly

    OpenAIRE

    Bates, Philip D.; Johnson, Sean R.; Cao, Xia; Li, Jia; Nam, Jeong-Won; Jaworski, Jan G.; Ohlrogge, John B; Browse, John

    2014-01-01

    Many plants produce valuable fatty acids in seed oils that provide renewable alternatives to petrochemicals for production of lubricants, coatings, or polymers. However, most plants producing these unusual fatty acids are unsuitable as crops. Metabolic engineering of oilseed crops, or model species, to produce the high-value unusual fatty acids has produced only low yields of the desired products, and previous research has indicated fatty acid degradation as a potential major factor hindering...

  5. 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 ...

  6. 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.

  7. 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

  8. 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.)

  9. 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.

  10. Influence of light on the free amino acid content and ?-aminobutyric acid synthesis in Brassica juncea seedlings.

    Science.gov (United States)

    Li, Xiaohua; Kim, Yeon Bok; Uddin, Md Romij; Lee, Sanghyun; Kim, Sun-Ju; Park, Sang Un

    2013-09-11

    Glutamate decarboxylase (GAD; EC 4.1.1.15) is an important enzyme in ?-aminobutyric acid (GABA) biosynthesis. Here we report the influence of light on amino acid accumulation and investigate the molecular mechanism by which light influences GABA biosynthesis at the seedling stage of two mustard (Brassica juncea) cultivars (green-leaf and purple-leaf). Gene expression profiles of four GAD-encoding genes (GAD1, GAD2, GAD4a, and GAD4b) and their impact on GABA biosynthesis were analyzed. Light exerted an obvious influence on amino acid accumulation in mustard seedlings. GAD gene expression was also significantly regulated by light/dark or dark treatment, which differentially regulated GABA biosynthesis in B. juncea seedlings. High-performance liquid chromatography (HPLC) revealed that the seeds of purple cultivars contain a higher amount of free amino acids and GABA than do the seeds of green cultivars. After seed germination, however, the accumulation of free amino acids peaked in dark-treated seedlings on day 9 in both cultivars, whereas GABA synthesis peaked at 9 days under light conditions. This study may provide a foundation for understanding the effect of light on amino acids, particularly GABA biosynthesis in Brassica plants. PMID:23909820

  11. 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.

  12. Enzymatic Synthesis of Fatty Hydroxamic Acid Derivatives Based on Palm Kernel Oil

    Directory of Open Access Journals (Sweden)

    Sidik Silong

    2011-08-01

    Full Text Available Fatty hydroxamic acid derivatives were synthesized using Lipozyme TL IM catalyst at biphasic medium as the palm kernel oil was dissolved in hexane and hydroxylamine derivatives were dissolved in water: (1 N-methyl fatty hydroxamic acids (MFHAs; (2 N-isopropyl fatty hydroxamic acids (IPFHAs and (3 N-benzyl fatty hydroxamic acids (BFHAs were synthesized by reaction of palm kernel oil and N-methyl hydroxylamine (N-MHA, N-isopropyl hydroxylamine (N-IPHA and N-benzyl hydroxylamine (N-BHA, respectively. Finally, after separation the products were characterized by color testing, elemental analysis, FT-IR and 1H-NMR spectroscopy. For achieving the highest conversion percentage of product the optimum molar ratio of reactants was obtained by changing the ratio of reactants while other reaction parameters were kept constant. For synthesis of MFHAs the optimum mol ratio of N-MHA/palm kernel oil = 6/1 and the highest conversion was 77.8%, for synthesis of IPFHAs the optimum mol ratio of N-IPHA/palm kernel oil = 7/1 and the highest conversion was 65.4% and for synthesis of BFHAs the optimum mol ratio of N-BHA/palm kernel oil = 7/1 and the highest conversion was 61.7%.

  13. [New biological active derivatives of indomethacin and acetylsalicylic acid. Synthesis, physico-chemical characterisation and structure validation].

    Science.gov (United States)

    Stan, Catalina; Stefanache, Alina; Dumitrache, M

    2006-01-01

    It is well known that niflumic acid glycinamide has a good antiinflammatory action useful in gum inflammatory diseases. The objective of this study was to obtain new glycinamides of acetylsalicylic acid and indomethacin, which could have a better antiinflammatory action than niflumic acid glycinamide. The study presents the synthesis, physico-chemical characterisation and structure validation of these glycinamides. PMID:17438920

  14. 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...

  15. 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

  16. 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 ...

  17. 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)

  18. Synthesis and antifungal activity of bile acid-derived oxazoles.

    Science.gov (United States)

    Fernández, Lucía R; Svetaz, Laura; Butassi, Estefanía; Zacchino, Susana A; Palermo, Jorge A; Sánchez, Marianela

    2016-04-01

    Peracetylated bile acids (1a-g) were used as starting materials for the preparation of fourteen new derivatives bearing an oxazole moiety in their side chain (6a-g, 8a-g). The key step for the synthetic path was a Dakin-West reaction followed by a Robinson-Gabriel cyclodehydration. A simpler model oxazole (12) was also synthesized. The antifungal activity of the new compounds (6a-g) as well as their starting bile acids (1a-g) was tested against Candida albicans. Compounds 6e and 6g showed the highest percentages of inhibition (63.84% and 61.40% at 250μg/mL respectively). Deacetylation of compounds 6a-g, led to compounds 8a-g which showed lower activities than the acetylated derivatives. PMID:26827629

  19. 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.

  20. Poly(ethylene terephthalate) surface modification by deep UV (172 nm) irradiation

    International Nuclear Information System (INIS)

    The prospects of obtaining desired surface-mediated characteristics while retaining bulk-mediated physical properties and avoiding potential environmental issues with wet chemical technology lends considerable appeal to photochemical approaches. We investigated the response of poly(ethylene terephthalate) to 172 nm UV from a xenon excimer lamp in the absence of oxygen, using XPS, ToF/SIMS, and AFM. The main effects are increasing loss of a C=O moiety and carboxylic acid production without effect on topography upto a total fluence of 16 J/cm2. Above this level no further change in surface chemistry was evident, but surfaces became rougher, suggesting the onset of etching

  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. 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...

  3. 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...

  4. Synthesis and biological activity of diisothiocyanate-derived mercapturic acids.

    Science.gov (United States)

    Grzywa, Renata; Winiarski, ?ukasz; Psurski, Mateusz; Rudnicka, Agata; Wietrzyk, Joanna; Gajda, Tadeusz; Oleksyszyn, Józef

    2016-01-15

    This Letter deals with new non-natural diisothiocyanates, their mercapturic acid derivatives-conjugated with N-acetylcysteine as well as their antiproliferative activity towards human colon cancer cell lines and their inhibitory potency towards histone deacetylase activity. The activity of analysed isothiocyanates is not significantly different than their N-acetylcysteine conjugates. In comparison to simple mono-isothiocyanate analogues, aliphatic diisothiocyanates and their conjugates are much more active than the simple presence of two isothiocyanate functionalities could indicate. PMID:26639764

  5. 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.

  6. 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...

  7. 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  |

  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. 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)

  10. 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)

  11. 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.

  12. Thorium terephthalates coordination polymers synthesized in solvothermal DMF/H2O system.

    Science.gov (United States)

    Falaise, Clément; Charles, Jean-Sébastien; Volkringer, Christophe; Loiseau, Thierry

    2015-03-01

    A series of thorium-based terephthalates have been solvothermaly synthesized in N,N-dimethylformamide (DMF) with different amounts of water and various temperatures (100-150 °C). Without the addition of water, the Th-H2bdc-DMF system gives rise to the formation of two phases, Th(bdc)2(DMF)2 (1) and Th6O4(OH)4(H2O)6(bdc)6·6DMF·12H2O (3) (bdc = 1,4-benzenedicarboxylate or terephthalate). Their structures are built up of isolated thorium centers ThO8(DMF)2 for (1) and the hexanuclear core Th6O4(OH)4(H2O)6 for (3). The latter adopts the UiO-66 metal-organic framework topology and exhibits a very high porosity for an actinides-based porous material (BET surface up to 730(6) m(2)·g(-1)). The synthesis of (3) is also favored upon adding water. However, for pure aqueous solutions or for a very low amount of water, a third solid Th(bdc)2 (2) crystallizes and contains thorium monomers ThO8. The main similitude with the parent system dedicated to tetravalent uranium concerns the possibility to stabilize the An6O8(H2O)6 core by terephthalate linkers and to reproduce An(bdc)2(DMF)2 for both actinides U(4+) and Th(4+). The thermal treatment of the latter shows a structural transition into the crystalline Th(bdc)2 (2) solid. PMID:25668215

  13. Acid gradient across plasma membrane can drive phosphate bond synthesis in cancer cells: acidic tumor milieu as a potential energy source.

    Science.gov (United States)

    Dhar, Gautam; Sen, Suvajit; Chaudhuri, Gautam

    2015-01-01

    Aggressive cancers exhibit an efficient conversion of high amounts of glucose to lactate accompanied by acid secretion, a phenomenon popularly known as the Warburg effect. The acidic microenvironment and the alkaline cytosol create a proton-gradient (acid gradient) across the plasma membrane that represents proton-motive energy. Increasing experimental data from physiological relevant models suggest that acid gradient stimulates tumor proliferation, and can also support its energy needs. However, direct biochemical evidence linking extracellular acid gradient to generation of intracellular ATP are missing. In this work, we demonstrate that cancer cells can synthesize significant amounts of phosphate-bonds from phosphate in response to acid gradient across plasma membrane. The noted phenomenon exists in absence of glycolysis and mitochondrial ATP synthesis, and is unique to cancer. Biochemical assays using viable cancer cells, and purified plasma membrane vesicles utilizing radioactive phosphate, confirmed phosphate-bond synthesis from free phosphate (Pi), and also localization of this activity to the plasma membrane. In addition to ATP, predominant formation of pyrophosphate (PPi) from Pi was also observed when plasma membrane vesicles from cancer cells were subjected to trans-membrane acid gradient. Cancer cytosols were found capable of converting PPi to ATP, and also stimulate ATP synthesis from Pi from the vesicles. Acid gradient created through glucose metabolism by cancer cells, as observed in tumors, also proved critical for phosphate-bond synthesis. In brief, these observations reveal a role of acidic tumor milieu as a potential energy source and may offer a novel therapeutic target. PMID:25874623

  14. Effects of Long Chain Fatty Acid Synthesis and Associated Gene Expression in Microalga Tetraselmis sp.

    Directory of Open Access Journals (Sweden)

    T. Catalina Adarme-Vega

    2014-06-01

    Full Text Available With the depletion of global fish stocks, caused by high demand and effective fishing techniques, alternative sources for long chain omega-3 fatty acids are required for human nutrition and aquaculture feeds. Recent research has focused on land-based cultivation of microalgae, the primary producers of omega-3 fatty acids in the marine food web. The effect of salinity on fatty acids and related gene expression was studied in the model marine microalga, Tetraselmis sp. M8. Correlations were found for specific fatty acid biosynthesis and gene expression according to salinity and the growth phase. Low salinity was found to increase the conversion of C18:4 stearidonic acid (SDA to C20:4 eicosatetraenoic acid (ETA, correlating with increased transcript abundance of the ?-6-elongase-encoding gene in salinities of 5 and 10 ppt compared to higher salinity levels. The expression of the gene encoding ?-ketoacyl-coenzyme was also found to increase at lower salinities during the nutrient deprivation phase (Day 4, but decreased with further nutrient stress. Nutrient deprivation also triggered fatty acids synthesis at all salinities, and C20:5 eicosapentaenoic acid (EPA increased relative to total fatty acids, with nutrient starvation achieving a maximum of 7% EPA at Day 6 at a salinity of 40 ppt.

  15. 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)

  16. 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)

  17. 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.

  18. 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

  19. 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

  20. 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.