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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. Determining organic impurities in mother liquors from oxidative terephthalic acid synthesis by microemulsion electrokinetic chromatography.

    Science.gov (United States)

    Huang, Hsi-Ya; Wei, Mercury; Lin, Yu-Ru; Lu, Pin-Hsuan

    2009-03-20

    In this study, a microemulsion electrokinetic chromatography (MEEKC) method was developed to analyze and detect several aromatic acids (benzoic acid (BA), isophthalic acid (IPA), terephthalic acid (TPA), p-toluic acid (p-TA), 4-carboxylbenzaldehyde (4-CBA), trimesic acid (TSA), trimellitic acid (TMA), o-phthalic acid (OPA), and hemimellitic acid (HMA)), which are common organic impurities produced by liquid-phase catalytic oxidation of p-xylene to TPA. The effects of microemulsion composition, column temperature, column length and applied voltage were examined in order to optimize the aromatic acid separations. This work demonstrated that variation in the concentration of surfactant (sodium dodecyl sulfate (SDS)) and oil phase (octane) had a pronounced effect on separation of the nine aromatic acids. It was also found that a decrease in column length had the greatest effect on shortening separation time and improving separation resolution for these aromatic acids when compared to that of an increase in column temperature or applied voltage. However, the nature and concentration of cosurfactants and organic modifiers were found to play only minor roles in the separation mechanism. Thus, a separation with baseline resolution was achieved within 14 min by using a microemulsion solution of pH 2.0 containing 3.7% SDS, 0.975% octane, and 5.0% cyclohexanol; and a 50-cm capillary column (effective length of 40-cm) at 26 degrees C. As a result, the developed MEEKC method successfully determined eight impurities of aromatic acids in the mother liquors produced from the oxidation synthesis of TPA. PMID:19167001

  3. 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.

  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. Electrochemical synthesis of FeS{sub 2} thin film: An effective material for peroxide sensing and terephthalic acid degradation

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Sumanta [Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103 WB (India); Mondal, Palash; Tripathi, Subhankar [Department of Chemistry, Vivekananda Mahavidyalaya, Burdwan, 713103 WB (India); Mondal, Anup [Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103 WB (India); Chakraborty, Biswajit, E-mail: biswajitmailbag@gmail.com [Department of Chemistry, Vivekananda Mahavidyalaya, Burdwan, 713103 WB (India)

    2015-10-15

    Electrochemically FeS{sub 2} 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 FeS{sub 2} 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 FeS{sub 2} and ITO layer. Cyclic voltametry study shows that FeS{sub 2}/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 FeS{sub 2} thin films have been synthesized on ITO substrate. The synthesized material is effective for the reduction of H{sub 2}O{sub 2} 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 FeS{sub 2} thin films are synthesized. • The material is effective to sense the H{sub 2}O{sub 2} and degrade terephthalic acid. • It plays a dual role as pollutant cleanup for environmental interest.

  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 μ2-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 μ4-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. Bio-based poly(ethylene terephthalate) copolyesters made from cyclic monomers derived from tartaric acid

    OpenAIRE

    Japu, Cristina; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; Muñoz Guerra, Sebastián

    2014-01-01

    Two cyclic acetal compounds, 2,3-O-methylene L-threitol and dimethyl 2,3-O-methylene L-threarate, both coming from naturally-occurring tartaric acid, were used as comonomers to replace ethylene glycol and dimethyl terephthalate respectively, in the preparation of PET-based copolyesters by polycondensation in the melt. Synthesis results, structure and thermal properties of the two afforded copolyester series were evaluated and compared regarding composition and type of comonomer used in each c...

  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. 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.

  15. 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.

  16. 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.

  17. 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

  18. THE IMPROVEMENT IN THE TECHNOLOGICAL PROCESS OF OBTAINING TECHNICAL TEREPHTHALIC ACID

    OpenAIRE

    Gimaev, M.; Badikova, A.; Kudasheva, F.

    2011-01-01

    Presents the results of investigation of the composition of by-product a mixture of organic acids (MOA) process for obtaining of terephthalic acid physico-chemical methods of the analysis of IR-spectrometry on the IR-Fourier spectrometer IR Prestige-21, high performance liquid chromatography on liquid chromatograph Hewlett Packard (USA). Studied methods of cleaning MOA. Developed and tested method of cleaning MOA sulfuric acid cleaning MOA sulfuric acid, selected the optimal conditions of the...

  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. Surface-mediated nucleation in the solid-state polymorph transformation of terephthalic acid.

    Science.gov (United States)

    Beckham, Gregg T; Peters, Baron; Starbuck, Cindy; Variankaval, Narayan; Trout, Bernhardt L

    2007-04-18

    A molecular mechanism for nucleation for the solid-state polymorph transformation of terephthalic acid is presented. New methods recently developed in our group, aimless shooting and likelihood maximization, are employed to construct a model for the reaction coordinate for the two system sizes studied. The reaction coordinate approximation is validated using the committor probability analysis. The transformation proceeds via a localized, elongated nucleus along the crystal edge formed by fluctuations in the supramolecular synthons, suggesting a nucleation and growth mechanism in the macroscopic system. PMID:17385859

  9. Biological and Tribological Assessment of Poly(Ethylene Oxide Terephthalate)/Poly(Butylene Terephthalate), Polycaprolactone, and Poly (L\\DL) Lactic Acid Plotted Scaffolds for Skeletal Tissue Regeneration.

    Science.gov (United States)

    Hendrikson, Wilhelmus J; Zeng, Xiangqiong; Rouwkema, Jeroen; van Blitterswijk, Clemens A; van der Heide, Emile; Moroni, Lorenzo

    2016-01-01

    Additive manufactured scaffolds are fabricated from three commonly used biomaterials, polycaprolactone (PCL), poly (L\\DL) lactic acid (P(L\\DL)LA), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT). Scaffolds are compared biologically and tribologically. Cell-seeded PEOT/PBT scaffolds cultured in osteogenic and chondrogenic differentiation media show statistical significantly higher alkaline phosphatase (ALP) activity/DNA and glycosaminoglycans (GAG)/DNA ratios, followed by PCL and P(L\\DL)LA scaffolds, respectively. The tribological performance is assessed by determining the friction coefficients of the scaffolds at different loads and sliding velocities. With increasing load or decreasing sliding velocity, the friction coefficient value decreases. PEOT/PBT show to have the lowest friction coefficient value, followed by PCL and P(L\\DL)LA. The influence of the scaffold architecture is further determined with PEOT/PBT. Reducing of the fiber spacing results in a lower friction coefficient value. The best and the worst performing scaffold architecture are chosen to investigate the effect of cell culture on the friction coefficient. Matrix deposition is low in the cell-seeded scaffolds and the effect is, therefore, undetermined. Taken together, our studies show that PEOT/PBT scaffolds support better skeletal differentiation of seeded stromal cells and lower friction coefficient compared to PCL and P(L/DL)A scaffolds. PMID:26775915

  10. 4-[(E-2-(Pyridin-2-ylethenyl]pyridineterephthalic acid (2/1

    Directory of Open Access Journals (Sweden)

    Paola Castro-Montes

    2012-12-01

    Full Text Available The title 2:1 co-crystal, 2C12H10N2C8H6O4, 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 ABAB. Further linkage through weak CH...O and CH...? interactions gives two-dimensional hydrogen-bonded undulating sheets propagating in the [100] and [010] directions. These layers are connected through additional weak CH...O contacts, forming a three-dimensional structure.

  11. 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)

  12. 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.

  13. 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...

  14. 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...

  15. 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...

  16. 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

  17. Development of a Composite Electrospun Polyethylene Terephthalate-Polyglycolic Acid Material: Potential Use as a Drug-Eluting Vascular Graft

    OpenAIRE

    Nabzdyk, Christoph S.; Maggie Chun; Pathan, Saif G.; Nelson, David W.; Jin-Oh You; Matthew D. Phaneuf; Logerfo, Frank W.; Leena Pradhan-Nabzdyk

    2015-01-01

    Intimal hyperplasia (IH), an excessive wound healing response of an injured vessel wall after bypass grafting, typically leads to prosthetic bypass graft failure. In an approach to ameliorate IH, nondegradable poly(ethylene terephthalate) or PET, which has been used in prosthetic vascular grafts for over 60 years, and biodegradable poly(glycolic acid) or PGA were electrospun using different techniques to generate a material that may serve as permanent scaffold and as a drug/biologic delivery ...

  18. Anticancer studies of drug encapsulated polyethylene terephthalate-Co-polylactic acid nanocapsules

    Directory of Open Access Journals (Sweden)

    K Sathish Kumar

    2011-01-01

    Full Text Available Objectives: The purpose of this study was to investigate the anticancer activity of anticancer drugs (5-fluorouracil and 6-thioguanine in polymeric nanocapsules in the presence and in the absence of gold and iron oxide nanoparticles toward Hep2 cancer cells. Materials and Methods: MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay was used for quantitative measurements for the anticancer cell activity. Encapsulated drug in polyethylene terephthalate-polylactic acid copolymer (PET-co-PLA nanocapsules in the presence and absence of gold and iron oxide nanoparticles were prepared via the W/O/W emulsification solvent-evaporation method. Morphology of the nanoparticles was characterized by transmission electron microscopy and scanning electron microscopy. Conclusion: The average size of the polymeric nanocapsules, gold nanoparticles, and iron oxide nanoparticles were found to be in range of 230-260, 18 -20 nm, 5-10 nm, respectively. The findings in this study inferred that incorporated drug in polymeric nanocapsules with gold nanoparticles and iron oxide nanoparticles show better anticancer activity when compared with encapsulated drug in polymeric nanocapsules.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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...

  5. Construction of antibacterial poly(ethylene terephthalate) films via layer by layer assembly of chitosan and hyaluronic acid.

    Science.gov (United States)

    Del Hoyo-Gallego, Sara; Pérez-Álvarez, Leyre; Gómez-Galván, Flor; Lizundia, Erlantz; Kuritka, Ivo; Sedlarik, Vladimir; Laza, Jose Manuel; Vila-Vilela, Jose Luis

    2016-06-01

    Polyelectrolytic multilayers (PEMs) with enhanced antibacterial properties were built up onto commercial poly(ethylene terephthalate) (PET) films based on the layer by layer assembling of bacterial contact killing chitosan and bacterial repelling highly hydrated hyaluronic acid. The optimization of the aminolysis modification reaction of PET was carried out by the study of the mechanical properties and the surface characterization of the modified polymers. The layer by layer assembly was successfully monitored by TEM microscopy, surface zeta-potential, contact angle measurements and, after labeling with fluorescein isothiocyanate (FTIC) by absorption spectroscopy and confocal fluorescent microscopy. Beside, the stability of the PEMs was studied at physiological conditions in absence and in the presence of lysozyme and hyaluronidase enzymes. Antibacterial properties of the obtained PEMs against Escherichia coli were compared with original commercial PET. PMID:27083341

  6. 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

  7. 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.

  8. 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)

  9. 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.

  10. A Novel and Highly Regioselective Synthesis of New Carbamoylcarboxylic Acids from Dianhydrides

    OpenAIRE

    Adrián Ochoa-Terán; Jesús Estrada-Manjarrez; Marisela Martínez-Quiroz; Marco A. Landey-Álvarez; Eleazar Alcántar Zavala; Georgina Pina-Luis; Hisila Santacruz Ortega; Luis Enrique Gómez-Pineda; José-Zeferino Ramírez; Daniel Chávez; Julio Montes Ávila; Victoria Labastida-Galván; Mario Ordoñez

    2014-01-01

    A regioselective synthesis has been developed for the preparation of a series of N,N′-disubstituted 4,4′-carbonylbis(carbamoylbenzoic) acids and N,N′-disubstituted bis(carbamoyl) terephthalic acids by treatment of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (1) and 1,2,4,5-benzenetetracarboxylic dianhydride (2) with arylalkyl primary amines (A-N). The carbamoylcarboxylic acid derivatives were synthesized with good yield and high purity. The specific reaction conditions were established ...

  11. 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)

  12. 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)

  13. Synthesis, Structures and Luminescence Properties of Metal-Organic Frameworks Based on Lithium-Lanthanide and Terephthalate

    Directory of Open Access Journals (Sweden)

    Mohammed S. M. Abdelbaky

    2016-03-01

    Full Text Available Metal-organic frameworks assembled from Ln(III, Li(I and rigid dicarboxylate ligand, formulated as [LiLn(BDC2(H2O·2(H2O] (MS1-6,7a and [LiTb(BDC2] (MS7b (Ln = Tb, Dy, Ho, Er, Yb, Y0.96Eu0.04, Y0.93Tb0.07, and H2BDC = terephthalic acid, were obtained under hydrothermal conditions. The isostructural MS1-6 crystallize in monoclinic P21/c space group. While, in the case of Tb3+ a mixture of at least two phases was obtained, the former one (MS7a and a new monoclinic C2/c phase (MS7b. All compounds have been studied by single-crystal and powder X-ray diffraction, thermal analyses (TGA, vibrational spectroscopy (FTIR, and scanning electron microscopy (SEM-EDX. The structures of MS1-6 and MS7a are built up of inorganic-organic hybrid chains. These chains constructed from unusual four-membered rings, are formed by edge- and vertex-shared {LnO8} and {LiO4} polyhedra through oxygen atoms O3 (vertex and O6-O7 (edge. Each chain is cross-linked to six neighboring chains through six terephthalate bridges. While, the structure of MS7b is constructed from double inorganic chains, and each chain is, in turn, related symmetrically to the adjacent one through the c glide plane. These chains are formed by infinitely alternating {LiO4} and {TbO8} polyhedra through (O2-O3 edges to create Tb–O–Li connectivity along the c-axis. Both MS1-6,7a and MS7b structures possess a 3D framework with 1D trigonal channels running along the a and c axes, containing water molecules and anhydrous, respectively. Topological studies revealed that MS1-6 and MS7a have a new 2-nodal 3,10-c net, while MS7b generates a 3D net with unusual β-Sn topology. The photoluminescence properties Eu- and Tb-doped compounds (MS5-6 are also investigated, exhibiting strong red and green light emissions, respectively, which are attributed to the efficient energy transfer process from the BDC ligand to Eu3+ and Tb3+.

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

    Science.gov (United States)

    Yener, H. Banu; Helvacı, Şerife Ş.

    2015-09-01

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

  15. Facile preparation of super-hydrophilic poly(ethylene terephthalate) fabric using dilute sulfuric acid under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Fang [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Guangxian, E-mail: zgx656472@sina.com.cn [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Fengxiu [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang, Yuansong [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China)

    2015-09-15

    Highlights: • A durable super-hydrophilic PET fabric was prepared using dilute H{sub 2}SO{sub 4} under microwave irradiation. • Dilute sulfuric acid was gradually concentrated enough to sulfonate PET fabric. • Microwave irradiation made PET fabric modification highly efficient. • The mechanical properties of modified PET fibers were kept well. • The method was novel, rapid, and eco-friendly. - Abstract: The hydrophilicity of a poly(ethylene terephthalate) (PET) fabric was greatly modified by using dilute sulfuric acid, which gradually became concentrated enough to sulfonate the fabric when microwave irradiation (MW) was applied. The modified PET fabric was super-hydrophilic. Modifying the fabric caused the water contact angle to decrease from 132.46 (for the unmodified fabric) to 0°, the water absorption rate to increase from 36.45 to 119.78%, and the capillary rise height to increase from 0.4 to 14.4 cm. The hydrophilicity of the modified PET fabric was not affected by washing it many times. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that there were sulfonic acid groups on the modified fibers. Almost no difference between the surfaces of the unmodified and modified PET fibers was found using scanning electron microscopy. Analysis by differential scanning calorimetry showed that the unmodified and modified fabrics had similar thermostabilities. X-ray diffraction analysis of the crystalline structures of the unmodified and modified fibers showed that they were almost the same. The strength, elasticity, and rigidity of the unmodified fabric were retained by the modified fabric. The modified fabric had better dyeing properties than the unmodified fabric.

  16. Facile preparation of super-hydrophilic poly(ethylene terephthalate) fabric using dilute sulfuric acid under microwave irradiation

    International Nuclear Information System (INIS)

    Highlights: • A durable super-hydrophilic PET fabric was prepared using dilute H2SO4 under microwave irradiation. • Dilute sulfuric acid was gradually concentrated enough to sulfonate PET fabric. • Microwave irradiation made PET fabric modification highly efficient. • The mechanical properties of modified PET fibers were kept well. • The method was novel, rapid, and eco-friendly. - Abstract: The hydrophilicity of a poly(ethylene terephthalate) (PET) fabric was greatly modified by using dilute sulfuric acid, which gradually became concentrated enough to sulfonate the fabric when microwave irradiation (MW) was applied. The modified PET fabric was super-hydrophilic. Modifying the fabric caused the water contact angle to decrease from 132.46 (for the unmodified fabric) to 0°, the water absorption rate to increase from 36.45 to 119.78%, and the capillary rise height to increase from 0.4 to 14.4 cm. The hydrophilicity of the modified PET fabric was not affected by washing it many times. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that there were sulfonic acid groups on the modified fibers. Almost no difference between the surfaces of the unmodified and modified PET fibers was found using scanning electron microscopy. Analysis by differential scanning calorimetry showed that the unmodified and modified fabrics had similar thermostabilities. X-ray diffraction analysis of the crystalline structures of the unmodified and modified fibers showed that they were almost the same. The strength, elasticity, and rigidity of the unmodified fabric were retained by the modified fabric. The modified fabric had better dyeing properties than the unmodified fabric

  17. 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.)

  18. 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

  19. 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; Wll, 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.

  20. 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...

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

    OpenAIRE

    Irena VITKAUSKIENĖ

    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...

  2. 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?, 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

  3. 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?, Hseyin; Trker, A. Rehber; Co?kun, Ramazan; Saak, 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 97.30.4%, 98.30.2%, 94.10.3% and 96.50.6% 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.

  4. Synthesis, Spectroscopic Properties and Antioxidant Activity of Bis-Hydrazones and Schiff's bases Derived from Terephthalic Dihydrazide.

    Science.gov (United States)

    Jois, H S Vidyashree; Kalluraya, Balakrishna; Vishwanath, T

    2015-05-01

    A series of novel Schiff base containing bis-1,2,4-triazole and bis-hydrazone derived from terephthalic dihydrazide was synthesized. All the newly synthesized compounds were characterized by (1)H, (13)C NMR, mass spectra, FTIR and elemental analysis. UV-vis spectra and fluorescent spectra of the compounds were recorded. The effect of substituent such as electron withdrawing and electron donating groups on the fluorescent spectra was studied. Also, the comparative discussion on fluorescent spectra of Schiff's base and hydrazones has been described. The antioxidant activity of the compounds revealed that compound 5c and 5f are the most potent compounds in this series. PMID:25820870

  5. Electronic structures of bare and terephthalic acid adsorbed TiO2(110)-(1 × 2) reconstructed surfaces: origin and reactivity of the band gap states.

    Science.gov (United States)

    Zhang, Wenhua; Liu, Liming; Wan, Li; Liu, Lingyun; Cao, Liang; Xu, Faqiang; Zhao, Jin; Wu, Ziyu

    2015-08-21

    Combined core level spectroscopy, valence spectroscopy and density functional theory studies have probed the terephthalic acid (TPA) adsorption behavior and the electronic structure of the rutile TiO2(110)-(1 × 2) reconstructed surface at room temperature. The TiO2(110)-(1 × 2) reconstructed surface exhibits an electron rich nature owing to the unsaturated coordination of the surface terminated Ti2O3 rows. Deprotonation of TPA molecules upon adsorption produces both surface bridging hydroxyl (ObH) and bidentate terephthalate species with a saturation coverage of nearly 0.5 monolayers (ML). In contrast to the TiO2(110)-(1 × 1) surface, the band gap states (BGSs) on the bare (1 × 2) surface exhibit an asymmetric spectral feature, which is originated from integrated contributions of the Ti2O3 termination and the defects in the near-surface region. The Ti2O3 originated BGSs are found to be highly sensitive to the TPA adsorption, a phenomenon well reproduced by the density functional theory (DFT) calculations. Theoretical simulations of the adsorption process also suggest that the redistribution of the electronic density on the (1 × 2) reconstructed surface accompanying the hydroxyl formation promotes the disappearance of the Ti2O3-row derived BGS. PMID:26173487

  6. Morphology and thermal properties of electrospun fatty acids/polyethylene terephthalate composite fibers as novel form-stable phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Changzhong [Key Laboratory of Cellulose and Lignocellulosics Chemistry, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Linge [Key Laboratory of Cellulose and Lignocellulosics Chemistry, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650 (China); Department of Chemistry, University of Sheffield, Sheffield S3 7HF (United Kingdom); Huang, Yong [Key Laboratory of Cellulose and Lignocellulosics Chemistry, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650 (China); State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China)

    2008-11-15

    The ultrafine fibers based on the composites of polyethylene terephthalate (PET) and a series of fatty acids, lauric acid (LA), myristic acid (MA), palmitic acid (PA), and stearic acid (SA), were prepared successfully via electrospinning as form-stable phase change materials (PCMs). The morphology and thermal properties of the composite fibers were studied by field emission scanning electron microscopy (FE-SEM) and differential scanning calorimetry (DSC), respectively. It was found that the average fiber diameter increased generally with the content of fatty acid (LA) in the LA/PET composite fibers. The fibers with the low mass ratio maintained cylindrical shape with smooth surface while the quality became worse when the mass ratio is too high (more than 100/100). Moreover, the latent heat of the composite fibers increased with the increase of LA content and the phase transition temperature of the fibers have no obvious variations compared with LA. In contrast, both the latent heat and phase transition temperature of the fatty acid/PET composite fibers varied with the type of the fatty acids, and could be well maintained after 100 heating-cooling thermal cycles, which demonstrated that the composite fibers had good thermal stability and reliability. (author)

  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. 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

  9. 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.

  10. 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)

  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 OF MYCOPHENOLIC ACID (MPA)

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention relates to novel tools for improving MPA production. In particular, the present invention relates tofungal enzymes that are specific for MPA synthesis.......The present invention relates to novel tools for improving MPA production. In particular, the present invention relates tofungal enzymes that are specific for MPA synthesis....

  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. Biodegradation of poly(lactic acid), poly(hydroxybutyrate-co-hydroxyvalerate), poly(butylene succinate) and poly(butylene adipate-co-terephthalate) under anaerobic and oxygen limited thermophilic conditions

    OpenAIRE

    Jutakan Boonmee; Charnwit Kositanont; Thanawadee Leejarkpai

    2016-01-01

    In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid) (PLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS), and poly(butylene adipate-co-terephthalate) (PBAT) were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of b...

  15. Enantioselective Total Synthesis of Secalonic Acid E.

    Science.gov (United States)

    Ganapathy, Dhandapani; Reiner, Johannes R; Lffler, Lorenz E; Ma, Ling; Gnanaprakasam, Boopathy; Nieptter, 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. [Total synthesis of nordihydroguaiaretic acid].

    Science.gov (United States)

    Wu, A X; Zhao, Y R; Chen, N; Pan, X F

    1997-04-01

    beta-Keto ester(5) was obtained from vanilin through etherification, oxidation and condensation with acetoacetic ester, (5) on oxidative coupling reaction by NaOEt/I2 produced dimer (6) in high yield. Acid catalyzed cyclodehydration of (6) gave the furan derivative(7), and by a series of selective hydrogenation nordihydroguaiaretic acid, furoguaiacin dimethyl ether and dihydroguaiaretic acid dimethyl ether were synthesized. PMID:11499030

  17. 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.

  18. 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

  19. 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)

  20. 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

  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. 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

  3. 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....

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

    International Nuclear Information System (INIS)

    Highlights: ► Corrosion of ITO film on polymer substrate. ► Removal of In from ITO in acrylic acid. ► 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. 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.)

  6. Synthesis, NMR and crystal characterization of dimeric terephthalates derived from epimeric 4,5-seco-cholest-3-yn-5-ols.

    Science.gov (United States)

    Alarcón-Manjarrez, Carlos; Arcos-Ramos, Rafael; Álamo, Marcos Flores; Iglesias-Arteaga, Martín A

    2016-05-01

    Two dimeric steroidal terephthalates derived from epimeric 4,5-seco-cholest-3-yn-5-ols were prepared starting from cholesterol in a five-step synthetic sequence. X-ray crystallography shows that the obtained compounds display novel supramolecular networks in the solid state in which the facial hydrophobicity of the steroidal skeletons plays an important role. Unambiguous NMR characterization of the obtained dimers is also provided. PMID:26968130

  7. Free volume and microstructural investigation of poly(ethylene terephthalate)-g-acrylic acid (PET-g-AA) copolymer films

    International Nuclear Information System (INIS)

    Acrylic acid (AA) was grafted onto PET films by preirradiation method using a 60Co γ-radiation source. Microstructural investigation of the PET-g-AA copolymers has been carried out by wide angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA) and positron annihilation lifetime spectroscopy (PALS) techniques. The WAXD results showed only marginal variation in the crystallinity of the graft copolymers. Dynamic mechanical analysis showed an increase in the temperature of the α-relaxation and the tan δ value of subroom temperature secondary relaxations. From the PALS results, a complex variation of the free volume parameters, i.e. the o-positronium lifetime (τ3), its intensity (I3), fractional free volume (fv) and the intermediate lifetime component was observed for the graft copolymers. Multiple phenomena of the effect of secondary relaxations, additive behavior of the individual polymer free volume parameters and effects from interfacial defects have been invoked to understand the fluctuational nature of the free volume properties in the graft copolymers.

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

    Science.gov (United States)

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

  10. 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.

  11. 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

  12. 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.

  13. First total synthesis of prasinic acid and its anticancer activity.

    Science.gov (United States)

    Chakor, Narayan; Patil, Ganesh; Writer, Diana; Periyasamy, Giridharan; Sharma, Rajiv; Roychowdhury, Abhijit; Mishra, Prabhu Dutt

    2012-11-01

    The first total synthesis of prasinic acid is being reported along with its biological evaluation. The ten step synthesis involved readily available and cheap starting materials and can easily be transposed to large scale manufacturing. The crucial steps of the synthesis included the formation of two different aromatic units (7 and 9) and their coupling reaction. The synthetic prasinic acid exhibited moderate antitumor activity (IC(50) 4.3-9.1 μM) in different lines of cancer cells. PMID:23031589

  14. 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)

  15. 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.

  16. Genetic dissection of polyunsaturated fatty acid synthesis in Caenorhabditis elegans

    OpenAIRE

    WATTS, JENNIFER L.; Browse, John

    2002-01-01

    Polyunsaturated fatty acids (PUFAs) are important membrane components and precursors of signaling molecules. To investigate the roles of these fatty acids in growth, development, and neurological function in an animal system, we isolated Caenorhabditis elegans mutants deficient in PUFA synthesis by direct analysis of fatty acid composition. C. elegans possesses all the desaturase and elongase activities to synthesize arachidonic acid and eicosapentaenoic acid from saturated fatty acid precurs...

  17. 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.

  18. 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

  19. 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...

  20. 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.

  1. 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

  2. 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 α-sialylated oligosaccharides by automated solid-phase synthesis selectively.

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

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strmgaard, 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....

  4. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, Mauro A.; Silva, Larissa R.S.P.; Correa, Arlene G. [Universidade Federal de Sao Carlos (UFSCAR), Sao Carlos, SP (Brazil). Dept. de Quimica]. E-mail: agcorrea@power.ufscar.br

    2008-07-01

    In this paper we report the synthesis of a series of novel N-aryl anthranilic acids, with good to excellent yields, employing microwaves as heat source to promote the Ullmann coupling between anthranilic acids and aryl bromides possessing electron donating or withdrawing groups. (author)

  6. Ferrocene-containing nucleic acids. Synthesis and electrochemical properties

    International Nuclear Information System (INIS)

    The published data on the synthesis of ferrocene-containing nucleic acid fragments are generalised. The known methods are systematised and their advantages and disadvantages are discussed. The use of nucleoside, nucleotide and oligonucleotide conjugates with ferrocene in the design of systems for electrochemical detection of nucleic acids is considered.

  7. Oleochemical synthesis of an acid cleavable hydrophobe for surfactant use

    Science.gov (United States)

    The synthesis of a series of branched hydroxy stearates from commercially available methyl oleate and common organic acids is reported. A variety of different acids, with 3 to 8 carbon atoms, and also varying in their branching and functionality, were used. The kinetics of the ring opening reactio...

  8. 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.

  9. Nucleic acid and nucleotide-mediated synthesis of inorganic nanoparticles

    Science.gov (United States)

    Berti, Lorenzo; Burley, Glenn A.

    2008-02-01

    Since the advent of practical methods for achieving DNA metallization, the use of nucleic acids as templates for the synthesis of inorganic nanoparticles (NPs) has become an active area of study. It is now widely recognized that nucleic acids have the ability to control the growth and morphology of inorganic NPs. These biopolymers are particularly appealing as templating agents as their ease of synthesis in conjunction with the possibility of screening nucleotide composition, sequence and length, provides the means to modulate the physico-chemical properties of the resulting NPs. Several synthetic procedures leading to NPs with interesting photophysical properties as well as studies aimed at rationalizing the mechanism of nucleic acid-templated NP synthesis are now being reported. This progress article will outline the current understanding of the nucleic acid-templated process and provides an up to date reference in this nascent field.

  10. 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...

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

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele; Stensbl, Tine B; Madsen, Ulf; Bruner-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...

  12. Synthesis of β-(S-methyl)thioaspartic acid and derivatives

    OpenAIRE

    Heredia-Moya, Jorge; KIRK, KENNETH L.

    2008-01-01

    β-(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 β-(S-methyl)thioaspartic acid will be the availability of synthetic β-(S-methyl)thioaspartic acid as well as derivatives designed for peptide incorporation. We report here the synthesis of ...

  13. Effects of bile acid administration on bile acid synthesis and its circadian rhythm in man

    International Nuclear Information System (INIS)

    In man bile acid synthesis has a distinct circadian rhythm but the relationship of this rhythm to feedback inhibition by bile acid is unknown. We measured bile acid synthesis as release of 14CO2 from [26-14C]cholesterol every 2 hr in three normal volunteers during five separate 24-hr periods. Data were fitted by computer to a cosine curve to estimate amplitude and acrophase of the circadian rhythm. In an additional six volunteers, we measured synthesis every 2 hr from 8:00 a.m. to 4:00 p.m. only. During the control period, amplitude (expressed as percentage of mean synthesis) averaged 52% and acrophase averaged 6:49 a.m. During administration of ursodeoxycholic acid (15 mg per kg per day), synthesis averaged 126% of baseline (p less than 0.1), amplitude averaged 43% and acrophase averaged 6:20 a.m. During administration of chenodeoxycholic acid (15 mg per kg per day), synthesis averaged 43% of baseline (p less than 0.001), amplitude averaged 53% and acrophase averaged 9:04 a.m. Addition of prednisone to this regimen of chenodeoxycholic acid to eliminate release of 14CO2 from corticosteroid hormone synthesis resulted in a mean amplitude of 62% and a mean acrophase of 6:50 a.m., values very similar to those in the baseline period. Administration of prednisone alone also did not significantly alter the baseline amplitude (40%) or acrophase (6:28 a.m.). We conclude that neither chenodeoxycholic acid nor ursodeoxycholic acid significantly alters the circadian rhythm of bile acid synthesis in man

  14. Effects of bile acid administration on bile acid synthesis and its circadian rhythm in man

    Energy Technology Data Exchange (ETDEWEB)

    Pooler, P.A.; Duane, W.C.

    1988-09-01

    In man bile acid synthesis has a distinct circadian rhythm but the relationship of this rhythm to feedback inhibition by bile acid is unknown. We measured bile acid synthesis as release of 14CO2 from (26-14C)cholesterol every 2 hr in three normal volunteers during five separate 24-hr periods. Data were fitted by computer to a cosine curve to estimate amplitude and acrophase of the circadian rhythm. In an additional six volunteers, we measured synthesis every 2 hr from 8:00 a.m. to 4:00 p.m. only. During the control period, amplitude (expressed as percentage of mean synthesis) averaged 52% and acrophase averaged 6:49 a.m. During administration of ursodeoxycholic acid (15 mg per kg per day), synthesis averaged 126% of baseline (p less than 0.1), amplitude averaged 43% and acrophase averaged 6:20 a.m. During administration of chenodeoxycholic acid (15 mg per kg per day), synthesis averaged 43% of baseline (p less than 0.001), amplitude averaged 53% and acrophase averaged 9:04 a.m. Addition of prednisone to this regimen of chenodeoxycholic acid to eliminate release of 14CO2 from corticosteroid hormone synthesis resulted in a mean amplitude of 62% and a mean acrophase of 6:50 a.m., values very similar to those in the baseline period. Administration of prednisone alone also did not significantly alter the baseline amplitude (40%) or acrophase (6:28 a.m.). We conclude that neither chenodeoxycholic acid nor ursodeoxycholic acid significantly alters the circadian rhythm of bile acid synthesis in man.

  15. Catalytic methylenedianiline synthesis on porous solid acids

    OpenAIRE

    Salzinger, Michael

    2010-01-01

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

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. Lipase-catalyzed synthesis of fatty acid amide (erucamide) using fatty acid and urea.

    Science.gov (United States)

    Awasthi, Neeraj Praphulla; Singh, R P

    2007-01-01

    Ammonolysis of fatty acids to the corresponding fatty acid amides is efficiently catalysed by Candida antartica lipase (Novozym 435). In the present paper lipase-catalysed synthesis of erucamide by ammonolysis of erucic acid and urea in organic solvent medium was studied and optimal conditions for fatty amides synthesis were established. In this process erucic acid gave 88.74 % pure erucamide after 48 hour and 250 rpm at 60 degrees C with 1:4 molar ratio of erucic acid and urea, the organic solvent media is 50 ml tert-butyl alcohol (2-methyl-2-propanol). This process for synthesis is economical as we used urea in place of ammonia or other amidation reactant at atmospheric pressure. The amount of catalyst used is 3 %. PMID:17898456

  1. 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.

  2. 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)

  3. 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)

  4. Layer-by-layer hyaluronic acid-chitosan coating promoted new collagen ingrowth into a poly(ethylene terephthalate) artificial ligament in a rabbit medical collateral ligament (MCL) reconstruction model.

    Science.gov (United States)

    Li, Hong; Jiang, Jia; Ge, Yunsheng; Xu, Jialing; Zhang, Pengyun; Zhong, Wei; Chen, Shiyi

    2013-01-01

    The ideal artificial ligament graft should have favorable biocompatibility to facilitate cell adhesion, proliferation, and collagen regeneration. In this present study, surface modification was performed on a poly(ethylene terephthalate) (PET) artificial ligament graft by layer-by-layer (LBL) self-assembly coating of hyaluronic acid (HA) and chitosan (CS). The surface characterization of the ligament was examined using scanning electron microscopy, atomic force microscopy, and energy-dispersive X-ray spectroscopy. The results of in vitro culturing of human foreskin fibroblast cells supported the hypothesis that the LBL coating of CS-HA could promote the cell proliferation and adhesion on the sheets. A rabbit medical collateral ligament reconstruction model was used to evaluate the effect of this LBL coating in vivo. The final results proved that this LBL coating could significantly promote and enhance new collagen formation among the graft fibers. On the basis of these results, we conclude that such CS-HA assembly coating could enhance PET graft biocompatibility in vitro and in vivo, and a CS-HA-coated PET graft has considerable potential as a desirable substitute for ligament reconstruction. PMID:23565685

  5. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  6. 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)

  7. Biotin Synthesis Begins by Hijacking the Fatty Acid Synthetic Pathway

    OpenAIRE

    Lin, Steven; Hanson, Ryan E.; Cronan, John E.

    2010-01-01

    Although biotin is an essential enzyme cofactor found in all three domains of life, our knowledge of its biosynthesis remains fragmentary. Most of the carbon atoms of biotin are derived from pimelic acid, a seven carbon dicarboxylic acid, but the mechanism whereby Escherichia coli assembles this intermediate remains unknown. Genetic analysis identified only two genes of unknown function required for pimelate synthesis, bioC and bioH. We report in vivo and in vitro evidence that the pimeloyl m...

  8. 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

  9. 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).

  10. Inhibitory effect of novobiocin on ribonucleic acid synthesis during germination of Bacillus subtilis spores.

    OpenAIRE

    Matsuda, M; Kameyama, T

    1980-01-01

    Novobiocin inhibited ribonculeic acid synthesis during germination of Bacillus subtilis spores. Transcription of certain kinds of genes probably required a preceding conformational change in deoxyribonucleic acid.

  11. 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)

  12. Oxetane &-amido acids : synthesis and derivatisation

    OpenAIRE

    Lucas, Susana Dias, 1980-

    2009-01-01

    In the present work the potential of oxetane δ-amino acids as scaffolds was evaluated. While there is an ample precedence for the use of 6- and 5-membered carbohydrate-derived amino acids as scaffolds, there are no reports on oxetanebased libraries. The oxetane ring is an interesting source of rigidity and well-defined exit vectors, and this unit is present in some important naturally occurring bioactive molecules, such as taxol, oxetanocin or oxetin. Nevertheless, the intrinsic chemical and ...

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

    International Nuclear Information System (INIS)

    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 α-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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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....

  19. Lactide Synthesis and Chirality Control for Polylactic acid Production.

    Science.gov (United States)

    Van Wouwe, Pieter; Dusselier, Michiel; Vanleeuw, Evelien; Sels, Bert

    2016-05-10

    Polylactic acid (PLA) is a very promising biodegradable, renewable, and biocompatible polymer. Aside from its production, its application field is also increasing, with use not only in commodity applications but also as durables and in biomedicine. In the current PLA production scheme, the most expensive part is not the polymerization itself but obtaining the building blocks lactic acid (LA) and lactide, the actual cyclic monomer for polymerization. Although the synthesis of LA and the polymerization have been studied systematically, reports of lactide synthesis are scarce. Most lactide synthesis methods are described in patent literature, and current energy-intensive, aselective industrial processes are based on archaic scientific literature. This Review, therefore, highlights new methods with a technical comparison and description of the different approaches. Water-removal methodologies are compared, as this is a crucial factor in PLA production. Apart from the synthesis of lactide, this Review also emphasizes the use of chemically produced racemic lactic acid (esters) as a starting point in the PLA production scheme. Stereochemically tailored PLA can be produced according to such a strategy, giving access to various polymer properties. PMID:27071863

  20. Effects of Pyrazinamide on Fatty Acid Synthesis by Whole Mycobacterial Cells and Purified Fatty Acid Synthase I

    OpenAIRE

    Boshoff, Helena I; Mizrahi, Valerie; Barry, Clifton E

    2002-01-01

    The effects of low extracellular pH and intracellular accumulation of weak organic acids were compared with respect to fatty acid synthesis by whole cells of Mycobacterium tuberculosis and Mycobacterium smegmatis. The profile of fatty acids synthesized during exposure to benzoic, nicotinic, or pyrazinoic acids, as well as that observed during intracellular hydrolysis of the corresponding amides, was not a direct consequence of modulation of fatty acid synthesis by these compounds but reflecte...

  1. 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

  2. Biotin synthesis begins by hijacking the fatty acid synthetic pathway.

    Science.gov (United States)

    Lin, Steven; Hanson, Ryan E; Cronan, John E

    2010-09-01

    Although biotin is an essential enzyme cofactor found in all three domains of life, our knowledge of its biosynthesis remains fragmentary. Most of the carbon atoms of biotin are derived from pimelic acid, a seven-carbon dicarboxylic acid, but the mechanism whereby this intermediate is assembled remains unknown. Genetic analysis in Escherichia coli identified only two genes of unknown function required for pimelate synthesis, bioC and bioH. We report in vivo and in vitro evidence that the pimeloyl moiety is synthesized by a modified fatty acid synthetic pathway in which the omega-carboxyl group of a malonyl-thioester is methylated by BioC, which allows recognition of this atypical substrate by the fatty acid synthetic enzymes. The malonyl-thioester methyl ester enters fatty acid synthesis as the primer and undergoes two reiterations of the fatty acid elongation cycle to give pimeloyl-acyl carrier protein (ACP) methyl ester, which is hydrolyzed to pimeloyl-ACP and methanol by BioH. PMID:20693992

  3. Ribosomal Synthesis of Peptides with Multiple β-Amino Acids.

    Science.gov (United States)

    Fujino, Tomoshige; Goto, Yuki; Suga, Hiroaki; Murakami, Hiroshi

    2016-02-17

    The compatibility of β-amino acids with ribosomal translation was studied for decades, but it has been still unclear whether the ribosome can accept various β-amino acids, and whether the ribosome can introduce multiple β-amino acids in a peptide. In the present study, by using the Escherichia coli reconstituted cell-free translation system with a reprogramed genetic code, we screened β-amino acids that give high single incorporation efficiency and used them to synthesize peptides containing multiple β-amino acids. The experiments of single β-amino acid incorporation into a peptide revealed that 13 β-amino acids are compatible with ribosomal translation. Six of the tested β-amino acids (βhGly, l-βhAla, l-βhGln, l-βhPhg, l-βhMet, and d-βhPhg) showed high incorporation efficiencies, and seven (l-βhLeu, l-βhIle, l-βhAsn, l-βhPhe, l-βhLys, d-βhAla, and d-βhLeu) showed moderate incorporation efficiencies; whereas no full-length peptide was produced using other β-amino acids (l-βhPro, l-βhTrp, and l-βhGlu). Subsequent double-incorporation experiments using β-amino acids with high single incorporation efficiency revealed that elongation of peptides with successive β-amino acids is prohibited. Efficiency of the double-incorporation of the β-amino acids was restored by the insertion of Tyr or Ile between the two β-amino acids. On the basis of these experiments, we also designed mRNA sequences of peptides, and demonstrated the ribosomal synthesis of peptides containing different types of β-amino acids at multiple positions. PMID:26807980

  4. Gluconic Acid Synthesis in an Electroenzymatic Reactor

    International Nuclear Information System (INIS)

    Highlights: • Novel membrane-less electroenzymatic reactor for gluconic acid production was developed. • Co-generation mode of operation, energy + material production. • The space time yield of reactor at glucose conversion of 47 % was 18.2 g h−1 cm−2. - Abstract: Glucose was selectively oxidized to gluconic acid in a membraneless, flow-through electroenzymatic reactor operated in the mode of co-generating chemicals and electrical energy. At the anode the enzyme glucose oxidase (GOx) in combination with the redox mediator tetrathiafulvalene (TTF) was used as catalyst, while the cathode was equipped with an enzyme cascade consisting of GOx and horseradish peroxidase (HRP). The influence of the electrode preparation procedure, the structural and the operating parameters on the reactor performance was investigated in detail. Under optimized conditions, an open circuit potential of 0.75 V, a current density of 0.6 mA cm−2 and a power density of 100 μA cm−2 were measured. The space time yield of gluconic acid achieved at a glucose conversion of 47% was 18.2 g h−1 cm−2

  5. 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.

  6. 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

  7. Synthesis and Lewis acidity of fluorophosphonium cations.

    Science.gov (United States)

    Caputo, Christopher B; Winkelhaus, Daniel; Dobrovetsky, Roman; Hounjet, Lindsay J; Stephan, Douglas W

    2015-07-21

    A series of fluorophosphonium salts, [R3PF][X] (R = alkyl or aryl; X = FB(C6F5)3, [B(C6F5)4]), have been prepared by reactions of phosphine/borane frustrated Lewis pairs (FLPs) with XeF2 or difluorophosphoranes with [Et3Si][B(C6F5)4]. As the substituents bound to phosphorus become increasingly electron withdrawing, the corresponding fluorophosphonium salts are shown to be increasingly Lewis acidic. Calculations were also performed to determine the relative fluoride ion affinities (FIA) of these fluorophosphonium cations. PMID:25785571

  8. 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...

  9. Synthesis, Characterization and Adsorption Capability of MOF-5

    OpenAIRE

    R.J.B. Balaguru; Rajan, K. S.; M.G. Kumar; N. Iswarya

    2012-01-01

    Metal Organic Frameworks (MOF) are three dimensional organic-inorganic hybrid crystalline materials where a metal containing inorganic cluster is coordinated to a polydentate organic ligand. MOF-5 consists of Zn4O inorganic moiety, that acts as secondary building unit, coordinating to benzene 1,4-dicarboxylate, a bidentate ligand that acts as spacers, to form a three dimensional structure. We report the synthesis of MOF-5 using zinc nitrate and terephthalic acid as precursors dissolved in dim...

  10. Is acetylcarnitine a substrate for fatty acid synthesis in plants

    Energy Technology Data Exchange (ETDEWEB)

    Roughan, G. (Horticulture Research Inst., Auckland (New Zealand)); Post-Beittenmiller, D.; Ohlrogge, J. (Michigan State Univ., East Lansing (United States)); Browse, J. (Washington State Univ., Pullman (United States))

    1993-04-01

    Long-chain fatty acid synthesis from [1-[sup 14]C]acetylcarnitine by chloroplasts isolated from spinach (Spinacia oleracea), pea (Pisum sativum), amaranthus (Amaranthus lividus), or maize (Zea mays) occurred at less than 2% of the rate of fatty acid synthesis from [1-[sup 14]C]acetate irrespective of the maturity of the leaves or whether the plastids were purified using sucrose or Percoll medium. [1-[sup 14]C]Acetylcarnitine was not significantly utilized by highly active chloroplasts rapidly prepared from pea and spinach using methods not involving density gradient centrifugation. [1-[sup 14]C]Acetylcarnitine was recovered quantitatively from chloroplast incubations following 10 min in the light. Unlabeled acetyl-L-carnitine (0.4 mM) did not compete with [1-[sup 14]C]acetate (0.2 mM) as a substrate for fatty acid synthesis by any of the more than 70 chloroplast preparations tested in this study. Carnitine acetyltransferase activity was not detected in any chloroplast preparation and was present in whole leaf homogenates at about 0.1% of the level of acetyl-coenzyme A synthetase activity. When supplied to detached pea shoots and detached spinach, amaranthus, and maize leaves via the transpiration stream, 1 to 4% of the [1-[sup 14]C]acetylcarnitine and 47 to 57% of the [1-[sup 14]C]acetate taken up was incorporated into lipids. Most (78--82%) of the [1-[sup 14]C]acetylcarnitine taken up was recovered intact. It is concluded that acetylcarnitine is not a major precursor for fatty acid synthesis in plants. 29 refs., 5 tabs.

  11. 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...

  12. 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

  13. 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 45C, 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

  14. 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.

  15. 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...

  16. Synthesis and crystal structure of maleopimaric acid.

    Science.gov (United States)

    Rao, Xiaoping; Song, Zhanqian; Yao, Xujie; Han, Chunrui; Shang, Shibin

    2008-01-01

    The title compound maleopimaric acid was synthesized by a Diels-Alder reaction between maleic anhydride and Pinus elliottii engelm oleoresin at room temperature and it was characterized by single crystal X-ray diffraction. The white crystals crystallized in the orthorhombic system, space group P2(12121) with cell dimensions: a = 7.6960 (15) A, b = 11.851 (2) A, c = 24.577 (5) A, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, V = 2241.6(8) A(3), and R(1) = 0.0716, wR(2) = 0.1975. The two fused and unbridged cyclohexane rings form a trans ring junction with chair conformation with two methyl groups in axis positions, the anhydride ring is planar. Crystal water existed in the molecular and stabilized the structure through intermolecular hydrogen bonds. PMID:18626819

  17. 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

  18. In Vitro Fatty Acid Synthesis and Complex Lipid Metabolism in the Cyanobacterium Anabaena variabilis: I. Some Characteristics of Fatty Acid Synthesis.

    Science.gov (United States)

    Lem, N W; Stumpf, P K

    1984-01-01

    In vitro fatty acid synthesis was examined in crude cell extracts, soluble fractions, and 80% (NH(4))(2)SO(4) fractions from Anabaena variabilis M3. Fatty acid synthesis was absolutely dependent upon acyl carrier protein and required NADPH and NADH. Moreover, fatty acid synthesis and elongation occurred in the cytoplasm of the cell. The major fatty acid products were palmitic acid (16:0) and stearic acid (18:0). Of considerable interest, both stearoyl-acyl carrier protein and stearoyl-coenzyme A desaturases were not detected in any of the fractions from A. variabilis. The similarities and differences in fatty acid synthesis between A. variabilis and higher plant tissues are discussed with respect to the endosymbiotic theory of chloroplast evolution. PMID:16663367

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

    OpenAIRE

    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 100μM for 48 h, and RNA was extracted for real-time PCR analysis. ...

  20. Synthesis of a tetrasaccharide fragment of hyaluronic acid having a glucuronic acid at the reducing end

    OpenAIRE

    Vliegenthart, J. F. G.; Slaghek, T.M.; Hyppönen, T.K.; Ogawa, T.; Kamerling, J P

    1993-01-01

    A stereocontrolled synthesis of a tetrasaccharide fragment of hyaluronic acid, beta-p-methoxyphenyl glycoside of beta-D-GlcNAc-(1¨4)-beta-D-GlcNAc-(1¨3)-beta-D-GlcNAc-(1¨4)-D-GlcA, is presented.

  1. 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.

  2. 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.

  3. 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 α-ω 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 α-ω epoxyesters presented serve as a means to introduce carboxylic acid and amine functional groups into poly(lactic acid polymers via ring-opening copolymerization.

  4. 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.)

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Synthesis using alumina precursors subjected to acid attack

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Shaorong Wang; Weishuo Fang

    2011-01-01

    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....

  11. 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

  12. Chemical structure and microstructure of poly(alkylene terephthalate)s, their copolyesters, and their blends as studied by NMR

    OpenAIRE

    Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián

    2014-01-01

    The use of NMR spectroscopy in solution to investigate the chemical structure of engineering poly(alkylene terephthalate)s such as poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT), and poly(butylene terephthalate) (PBT) is reviewed. Chemical defects present in the polyester chain, such as oxydialkylene units, as well as accompanying side products such as cyclic oligomers generated in the polycondensation, are well detected in 1H NMR spectra. The technique is also dem...

  13. 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.

  14. Synthesis of a C-linked hyaluronic acid disaccharide mimetic

    OpenAIRE

    Ren, Zhong-Xu; Yang, Qiang; Price, Kenneth N.; Chen, Tianniu; Nygren, Cara; Turner, John. F. C.; Baker, David C

    2007-01-01

    The synthesis of a C-disaccharide that is designed as a mimetic for the repeating unit disaccharide of hyaluronic acid is described. The target compound was obtained via the SmI2-promoted coupling reaction of the sulfone, 2-acetamido-4,6-O-benzylidene-3-O-tert-butyldimethylsilyl-1,2-dideoxy-1-pyridinylsulfonyl-β-D-glucopyranose (6), and the aldehyde, p-methoxyphenyl 2,3-di-O-benzyl-4-deoxy-4-C-formyl-6-O-p-methoxybenzyl-β-D-glucopyranoside (14).

  15. 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)

  16. An improved synthesis of [15N] 16-Doxyl stearic acid

    International Nuclear Information System (INIS)

    An improved method for the synthesis of [15N] 16-Doxyl stearate, a fatty-acid spin label, is reported. The method requires only one mole of [15N] 2-amino-2-methyl propanol per mole of methyl keto stearate with an overall yield of about 50%. In contrast, the previous method produced only 1-3% yield. The great improvement in yield was achieved mainly through the reduction of reaction volume which increases the reaction rate by the law of mass action. (author)

  17. 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.

  18. Direct synthesis of hydrogen peroxide on palladium catalyst supported on sulfonic acid-functionalized silica

    OpenAIRE

    Blanco Brieva, Gema; Frutos Escrig, Pilar de; Campos Martín, José Miguel; García Fierro, José Luis

    2010-01-01

    The direct synthesis of H2O2 has been successfully achieved at high-concentration and high selectivity on Pd–loaded sulfonic acid-functionalized silica using non acidic solutions and reaction temperature of 313 K.

  19. 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 M each attenuated KYNA formation from L-KYN and D-KYN by ~35% and ~66%, respectively. ONOO- (25 M 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 M. 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

  20. 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

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

    OpenAIRE

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

  2. Regulation of bile acid synthesis in rat hepatocyte monolayer cultures

    International Nuclear Information System (INIS)

    Primary hepatocyte monolayer cultures (PHC) were prepared and incubated in serum free media. Cells from a cholestyramine fed rat converted exogenous [14C]-cholesterol into [14C]-bile acids at a 3-fold greater rate than rats fed a normal diet. PHC synthesize bile acids (BA) at a rate of approximately 0.06 μg/mg protein/h. The major bile acid composition, as determined by GLC, was β-muricholic acid (BMC) and cholic acid (CA) in a 3:1 ratio, respectively. PHC rapidly converted free BA and BA intermediates into taurine conjugated trihydroxy-BA up to 87h after plating. 3-Hydroxy-3-methylglutaryl-coenzyme A-reductase activity assayed in microsomes prepared from PHC, decreased during the initial 48h, then remained constant. Cholesterol 7α-hydroxylase activity decreased during the initial 48h, then increased during the next 48h. This occurred while whole cells produced BA at a linear rate. The effect of individual BA on bile acid synthesis (BAS) was also studied. Relative rates of BAS were measured as the conversion of [14C]-cholesterol into [14C]-BA. BA combinations were tested in order to simulate the composition of the enterohepatic circulation. The addition of TCA (525 μM) plus TCDCA (80μM), in concentrations which greatly exceed the concentration of BA (60μM) in rate portal blood, failed to inhibit BAS. BA plus phospholipid and/or cholesterol also did not inhibit BAS. Surprisingly, crude rat bile with a final concentration comparable to those in the synthetic mix inhibited [14C]-cholesterol conversion into [14C]-BA

  3. 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.

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

    International Nuclear Information System (INIS)

    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

  5. Role for deoxyribonucleic acid ligase in deoxyribonucleic acid polymerase I-dependent repair synthesis in toluene-treated Escherichia coli

    International Nuclear Information System (INIS)

    In a toluene-treated mutant of Escherichia coli K-12 having a temperature-sensitive, conditionally lethal mutation in the structural gene for deoxyribonucleic acid (DNA) ligase, an extensive DNA repair synthesis occurred in x-irradiated cells at the nonpermissive temperature, 420C. At the permissive temperature, 300C, nearly normal semiconservative synthesis and limited repair synthesis were observed when DNA ligase was activated by the addition of nicotinamide adenine dinucleotide. (auth)

  6. 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...

  7. 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.

  8. [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

  9. 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

  10. 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)

  11. 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.

  12. Improved synthesis of amino acid and dipeptide chloromethyl esters using bromochloromethane

    OpenAIRE

    P Gomes; Santos, MI; Trigo, MJ; Castanheiro, R; MOREIRA,R

    2003-01-01

    Peptide chloromethyl esters are important compounds in prodrug synthesis. A simple, mild and efficient method for the synthesis of chloromethyl esters of N-blocked amino acids and dipeptides using exclusively bromochloromethane is reported. These N-blocked amino acid and dipeptide chloromethyl esters react readily with the carboxylic acid group of aspirin and with the sulfonamido group of the antimalarial sulfamethazine, to give the corresponding prodrugs.

  13. 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...

  14. 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.

  15. 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

  16. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-15

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

  18. 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 starting materials. As a key step, the first facially selective hydroboration of a 5-methylidene[2...

  19. 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.

  20. 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

  1. Pore-expanded SBA-15 sulfonic acid silicas for biodiesel synthesis.

    Science.gov (United States)

    Dacquin, J P; Lee, A F; Pirez, C; Wilson, K

    2012-01-01

    Here we present the first application of pore-expanded SBA-15 in heterogeneous catalysis. Pore expansion over the range 6-14 nm confers a striking activity enhancement towards fatty acid methyl ester (FAME) synthesis from triglycerides (TAG), and free fatty acid (FFA), attributed to improved mass transport and acid site accessibility. PMID:22089025

  2. 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

  3. 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

  4. 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.

  5. Synthesis and properties of scandium carboxylate metal-organic frameworks

    OpenAIRE

    Gonzalez-Santiago, Berenice

    2015-01-01

    This work investigated the synthesis, characterisation and properties of known and novel scandium carboxylate Metal-organic Frameworks (MOFs). The first part reports the performance of these Sc-MOFs as Lewis acid catalysts. The porous MOF scandium trimesate MIL-100(Sc) and the scandium terephthalates such as MIL-101(Sc), MIL-88B(Sc) and MIL-68(Sc) (prepared as the Sc-analogue for the first time), and scandium biphenyldicarboxylate MIL-88D(Sc) were prepared and tested as Lewis acid catalysts. ...

  6. Synthesis of acid-functionalized composite via surface deposition of acid-containing amorphous carbon

    Science.gov (United States)

    Du, Bin; Zhang, Xuan; Lou, Lan-Lan; Dong, Yanling; Liu, Gaixia; Liu, Shuangxi

    2012-07-01

    A synthetic procedure, including two steps: a hydrothermal treatment using H2SO4 solution and a thermal treatment with concentrated H2SO4 in Teflon-lined stainless autoclaves was developed to synthesize acid-functionalized composite. In this process, the carbonization of glucose which contributed to the formation of carbon species with acid functional groups occurred on the silica surface. The resultant composite, investigated by powder XRD, low temperature N2 sorption and TEM, possessed well-defined mesostructure. And it was determined by XPS that amorphous carbon was deposited at the silica surface of SBA-15. The presence of multi-functional groups in the composite was confirmed by FT-IR results. Furthermore, carboxylic and sulfonic groups could be incorporated into the composite material via the covalent bond. The composite was employed as the catalyst for the acetalization of carbonyl compounds. It was suggested that acid sites were well dispersed, which was responsible for the good performance in the catalytic test. According to these facts, a synthesis route for mesostructured composite with acid functional groups has been proposed.

  7. 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

  8. 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

  9. 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

  10. WRINKLED1 Rescues Feedback Inhibition of Fatty Acid Synthesis in Hydroxylase-Expressing Seeds1[OPEN

    Science.gov (United States)

    Browse, John

    2016-01-01

    Previous attempts at engineering Arabidopsis (Arabidopsis thaliana) to produce seed oils containing hydroxy fatty acids (HFA) have resulted in low yields of HFA compared with the native castor (Ricinus communis) plant and caused undesirable effects, including reduced total oil content. Recent studies have led to an understanding of problems involved in the accumulation of HFA in oils of transgenic plants, which include metabolic bottlenecks and a decrease in the rate of fatty acid synthesis. Focusing on engineering the triacylglycerol assembly mechanisms led to modest increases in the HFA content of seed oil, but much room for improvement still remains. We hypothesized that engineering fatty acid synthesis in the plastids to increase flux would facilitate enhanced total incorporation of fatty acids, including HFA, into seed oil. The transcription factor WRINKLED1 (WRI1) positively regulates the expression of genes involved in fatty acid synthesis and controls seed oil levels. We overexpressed Arabidopsis WRI1 in seeds of a transgenic line expressing the castor fatty acid hydroxylase. The proportion of HFA in the oil, the total HFA per seed, and the total oil content of seeds increased to an average of 20.9%, 1.26 µg, and 32.2%, respectively, across five independent lines, compared with 17.6%, 0.83 µg, and 27.9%, respectively, for isogenic segregants. WRI1 and WRI1-regulated genes involved in fatty acid synthesis were up-regulated, providing for a corresponding increase in the rate of fatty acid synthesis.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. 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....

  20. 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)

  1. Stereoselective synthesis of a-hydroxy-b-amino acids: the chiral pool approach

    Directory of Open Access Journals (Sweden)

    RADOMIR N. SAICIC

    2004-11-01

    Full Text Available A method for the stereoselective homologation of a-amino acids into syn-a-hydroxy-b-amino acids is described, based on the conversion of stereoisomeric cyanohydrins into trans-oxazolines. The synthetic potential of the method is illustrated in the enantioselective formal synthesis of Bestatin.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-15

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

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

    International Nuclear Information System (INIS)

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

  4. 76 FR 9753 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...

    Science.gov (United States)

    2011-02-22

    ... of the antidumping duty order on polyethylene terephthalate film, sheet, and strip (``PET film... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic... (``POR''), November 6, 2008, through October 31, 2009. \\1\\ See Polyethylene Terephthalate Film,...

  5. 77 FR 73428 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China...

    Science.gov (United States)

    2012-12-10

    ... the antidumping duty order on polyethylene terephthalate film, sheet, and strip (``PET film'') from... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic... Duty Administrative Review: Polyethylene Terephthalate Film, Sheet, and Strip from the...

  6. 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...

  7. 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 100μM 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 100μM. 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 OSTα/β 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

  8. Inhibition of deoxyribonucleic acid gyrase: effects on nucleic acid synthesis and cell division in Escherichia coli K-12.

    OpenAIRE

    Fairweather, N F; Orr, E; Holland, I B

    1980-01-01

    Mutants of Escherichia coli resistant to the antibiotic clorobiocin are also coumermycin resistant, and the mutation to resistance in at least one mutant was mapped near gyrB. We conclude, therefore, that clorobiocin inhibits deoxyribonucleic acid gyrase, and the drug was used to probe the role of this enzyme in vivo. Deozyribonucleic acid synthesis was preferentially inhibited but not completely blocked by the antibiotic. Transcription and cell division were also markedly affected. However, ...

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

    International Nuclear Information System (INIS)

    The synthesis of threo-dl-methylphenidate (Ritalin 1), threo-dl-p-hydroxy-methylphenidate (3), threo-dl-ritalinic acid (2), and threo-dl-p-hydroxyritalinic acid (4) with deuterium incorporated in the piperidine ring is described. These compounds were synthesized for use as internal standards for mass fragmentographic assays of methylphenidate and its metabolites. The synthetic scheme described resulted in less than 0.05% 2H0 in the piperidine ring in any of the preparations. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-04-01

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

  11. The effect of nalidixic acid, rifampicin and chloramphenicol on the synthesis of phospholipase C in Bacillus cereus

    International Nuclear Information System (INIS)

    The effect of nalidixic acid, rifampicin and chloramphenicol on the synthesis of phospholipase C (EC 3.1.4.3) has been studied in washed Bacillus cereus cells resuspended in nutrient broth. In the absence of inhibitors, the synthesis showed a biphasic pattern. No synthesis or release of enzyme was found in the presence of chloramphenicol. When rifampicin was added, phospholipase C synthesis for 10-15 min. Nalidixic acid, at concentrations which inhibited DNA synthesis completely, permitted the synthesis of phospholipase C at the same rate and for a similar length of time as rifampicin. (author)

  12. 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.

  13. 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.)

  14. 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...

  15. Fibre Labelling. Polytrimethylene terephthalate - PTT- DuPont. Intermediate Report

    OpenAIRE

    PICCININI Paola; SENALDI Chiara; ALBERTO LOPES JOÃO FILIPE

    2013-01-01

    In November 2011, the European Commission’s Joint Research Centre (JRC) was entrusted by DG Enterprise to verify the validity and applicability of the testing methods, proposed by DuPont, for the identification and quantification of their new fibre polytrimethylene terephthalate (PTT). The fibre is a type of polyester that differs from the common one polyethylene terephthalate (PET) as it contains one more methylene group in the aliphatic chain that links the terephthalic moiet...

  16. 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 ...

  17. Polyethylene Terephthalate May Yield Endocrine Disruptors

    OpenAIRE

    Sax, Leonard

    2009-01-01

    Background Recent reports suggest that endocrine disruptors may leach into the contents of bottles made from polyethylene terephthalate (PET). PET is the main ingredient in most clear plastic containers used for beverages and condiments worldwide and has previously been generally assumed not to be a source of endocrine disruptors. Objective I begin by considering evidence that bottles made from PET may leach various phthalates that have been putatively identified as endocrine disruptors. I al...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  19. 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

  20. 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

  1. 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.

  2. Phenolic acids in the wild mushroom Ganoderma lucidum and synthesis of some possible metabolites.

    OpenAIRE

    Heleno, Sandrina A.; Ferreira, Isabel C. F. R.; Martins, Anabela; Esteves, Ana P.; Queiroz, Maria João R. P.

    2012-01-01

    Ganoderma lucidum is one of the most extensive!) studied mushrooms due to its medicinal properties, p-Hydroxybenzoic acid was the most abundant phenolic acid found in this mushroom. after HPLC-DAD-MS analysis. In the present work we describe the synthesis of glucuronide and methyl derivatives of p-hydroxybenzoic acid, which arc two of the main circulating metabolites found in humans. Their biological activity is going to be evaluated and compared to the parent compound in order...

  3. Synthesis of novel (1-alkanoyloxy-4-alkanoylaminobutylidene-1,1-bisphosphonic acid derivatives

    Directory of Open Access Journals (Sweden)

    Vepsäläinen Jouko J

    2006-02-01

    Full Text Available Abstract A novel strategy for the synthesis of (1-alkanoyloxy-4-alkanoylaminobutylidene-1,1-bisphosphonic acid derivatives (1a-d via (1-hydroxy-4-alkanoylaminobutylidene-1,1-bisphosphonic acid derivatives (2a-d, starting from alendronate has been developed with reasonable 51–77% overall yields. Intermediate products, (1-hydroxy-4-alkanoylaminobutylidene-1,1-bisphosphonic acid derivatives (2a-d, were prepared in water with reasonable to high yields (52–94%.

  4. Green Synthesis and Urease Inhibitory Activity of Spiro-Pyrimidinethiones/Spiro-Pyrimidinones-Barbituric Acid Derivatives

    OpenAIRE

    Mohammadi Ziarani, Ghodsi; Asadi, Shima; Faramarzi, Sakineh; Amanlou, Massoud

    2015-01-01

    Sulfonic acid functionalized SBA-15 (SBA-Pr-SO3H) with pore size 6 nm as an efficient heterogeneous nanoporous solid acid catalyst exhibited good catalytic activity in the Biginelli-like reaction in the synthesis of spiroheterobicyclic rings with good yield and good recyclability. Spiro-pyrimidinethiones/spiro-pyrimidinones-barbituric acid derivatives were synthesized in a simple and efficient method using the one-pot three-component reaction of a cyclic 1,3- dicarbonyl compounds (barbituric ...

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

    International Nuclear Information System (INIS)

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

  6. 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

  7. 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 ...

  8. 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)

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

    OpenAIRE

    Milosavljevi? Nedeljko B.; Milainovi? Nikola Z.; Filipovi? Jovanka M.; Kalagasidis-Krui? 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 ...

  10. 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 synthesized via reaction between boric acid and various carbon precursors, e.g. phenol-formaldehyde resin, sucrose, 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 diffraction (XRD) and scanning electron microscopy. Possible boron carbide yields up to 95 % ...

  11. Essential amino acid and carbohydrate ingestion before resistance exercise does not enhance postexercise muscle protein synthesis

    OpenAIRE

    Fujita, Satoshi; Dreyer, Hans C.; Drummond, Micah J.; Glynn, Erin L.; Volpi, Elena; Rasmussen, Blake B

    2008-01-01

    Ingestion of an essential amino acid-carbohydrate (EAA + CHO) solution following resistance exercise enhances muscle protein synthesis during postexercise recovery. It is unclear whether EAA + CHO ingestion before resistance exercise can improve direct measures of postexercise muscle protein synthesis (fractional synthetic rate; FSR). We hypothesized that EAA + CHO ingestion before a bout of resistance exercise would prevent the exercise-induced decrease in muscle FSR and would result in an e...

  12. Pectin feeding influences fecal bile acid excretion, hepatic bile acid and cholesterol synthesis and serum cholesterol in rats.

    Science.gov (United States)

    Garcia-Diez, F; Garcia-Mediavilla, V; Bayon, J E; Gonzalez-Gallego, J

    1996-07-01

    This study was designed to investigate the effects of pectin on cholesterol and bile acid metabolism and to elucidate the mechanisms involved in its hypolipidemic effect in rats. The key regulatory enzymes in cholesterol and bile acid metabolism, 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) and cholesterol 7alpha-hydroxylase, were determined. Circulating, hepatic, and biliary lipid concentrations and fecal bile acid excretion were also measured. Male Wistar rats were fed a fiber-free or a pectin-supplemented (7 g/100 g) diet for 4 wk. Bile flow and the biliary secretion of both bile acids and cholesterol were not significantly different than controls in pectin-fed rats. The addition of pectin to the diet resulted in lower serum and liver cholesterol concentrations (-27 and -17%, respectively). Fecal bile acid excretion (+168%) and the hepatic activity of cholesterol 7alpha-hydroxylase (+70%) were significantly higher in pectin-fed animals. HMG-CoA reductase activity was also significantly greater (+11%) in the presence of dietary pectin. Results of our study indicate that pectin, by enhancing fecal bile acid excretion, may cause increased hepatic synthesis of bile acids and liver depletion of cholesterol in rats, which results in a higher rate of cholesterol synthesis and reduced serum cholesterol concentrations. PMID:8683337

  13. 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

  14. 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

  15. 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.

  16. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Junker, L.H.; Davis, R.A. (Univ. of Colorado Health Sciences Center, Denver (USA))

    1989-12-01

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of (14C)cholesterol from (2-14C)acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of (14C)cholesterol from (2-14C)acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis.

  17. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    International Nuclear Information System (INIS)

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of [14C]cholesterol from [2-14C]acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of [14C]cholesterol from [2-14C]acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis

  18. 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.

  19. 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.

  20. Absence of unsaturated fatty acid synthesis in murine T lymphocytes.

    OpenAIRE

    Buttke, T M; Cleave, S. Van; Steelman, L; McCubrey, J A

    1989-01-01

    Stearic acid is toxic for T lymphocytes in vitro but has little effect on B lymphocytes. To investigate the molecular basis for this difference, purified murine T and B lymphocytes were compared for their abilities to incorporate and metabolize stearic acid. Unstimulated T and B cells incorporated identical amounts of stearic acid into six different phospholipids and four neutral lipids. After mitogen stimulation, fatty acid uptake was increased in both lymphocyte types, but cell-specific dif...

  1. 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

  2. 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.

  3. Synthesis of [18-14C]octatriacontane from [1-14C]stearic acid

    International Nuclear Information System (INIS)

    A method was developed to synthesize 14C-labelled n-alkanes for use in cigarette smoke studies. Specifically, n-[18-14C]-octatriacontane was synthesized from 1 mCi [1-14C]stearic acid in a radiochemical yield of 20%. The key features of this synthesis were two consecutive alkylations of tosylmethyl isocyanide followed by acid hydrolysis to [18-14C]-19-octatriacontanone and modified Wolff-Kishner reduction to the n-alkane. After purification on silica gel 25 mg of [18-14C]octatriacontane was obtained with a total radioactivity of 200 μCi, a specific activity of 4.3 mCi/mmol, and a radiochemical purity in excess of 98% by thin layer radiochromatography. The method has also been applied to the synthesis of unlabeled n-pentatriacontane and is considered to be generally applicable to the synthesis of radiolabeled alkanes from radiolabeled fatty acids. (author)

  4. 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.

  5. 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 ...

  6. 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

  7. 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

  8. Synthesis and pharmacology of 3-isoxazolol amino acids as selective antagonists at group I metabotropic glutamic acid receptors

    DEFF Research Database (Denmark)

    Madsen, U; Bräuner-Osborne, H; Frydenvang, Karla Andrea; Hvene, L; Johansen, T N; Nielsen, B; Sánchez, C; Stensbøl, T B; Bischoff, F; Krogsgaard-Larsen, P

    2001-01-01

    Using ibotenic acid (2) as a lead, two series of 3-isoxazolol amino acid ligands for (S)-glutamic acid (Glu, 1) receptors have been developed. Whereas analogues of (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid [AMPA, (RS)-3] interact selectively with ionotropic Glu receptors (i......GluRs), the few analogues of (RS)-2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid [HIBO, (RS)-4] so far known typically interact with iGluRs as well as metabotropic Glu receptors (mGluRs). We here report the synthesis and pharmacology of a series of 4-substituted analogues of HIBO. The hexyl analogue 9 was...

  9. 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.

  10. 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

  11. 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.

  12. Surface effect of two different calcium fluoride fillers on the non-isothermal crystallization behavior of poly(ethylene terephthalate)

    OpenAIRE

    Sánchez Leija, Regina Janet; Riba, Marta; Cayuela Marín, Diana; Dominguez Espinos, Octavio; Sanchez Loredo, Maria Guadalupe

    2014-01-01

    Two different types of calcium fluoride (CaF2) particles were incorporated into a poly(ethylene terephthalate) (PET) matrix, fine particles (approximate to 350nm), and nanoparticles (approximate to 70nm). Both of them were synthesized by a chemical precipitation method using triethanolamine (TEA) as stabilizer. To obtain the nanoparticles, a greater amount of TEA was added during the synthesis in order to limit their growth. Therefore, unlike the fine particles, nanoparticles contained a grea...

  13. 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)

  14. 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...

  15. 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...

  16. 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).

  17. Relationship of lipogenic enzyme activities to the rate of rat liver fatty acid synthesis

    International Nuclear Information System (INIS)

    The mechanism by which diet regulates liver lipogenesis is unclear. Here the authors report how dietary alterations effect the activities of key enzymes of fatty acid (FA) synthesis. Male Sprague-Dawley rats, 400-500 g, were fasted for 48h and then refed a fat-free, high carbohydrate (HC) diet (75% cal. from sucrose) for 0,3,9,24 and 48h, or refed a HC diet for 48h, then fed a high-fat (HF) diet (44% cal. from corn oil) for 3,9,24 and 48h. The FA synthesis rate and the activities of acetyl CoA carboxylase (AC), fatty acid synthase (FAS), ATP citrate lyase (CL), and glucose 6-phosphate dehydrogenase (G6PDH) were determined in the livers. FA synthesis was assayed with 3H2O, enzyme activities were measured spectrophotometrically except for AC which was assayed with 14C-bicarbonate. There was no change in the activity of AC during fasting or on the HC diet. Fasting decreased the rate of FA synthesis by 25% and the activities of FAS and CL by 50%; refeeding the HC diet induced parallel changes in FA synthesis and the activities of FAS, CL, and G6PDH. After 9h on the HF diet, FA synthesis had decreased sharply, AC activity increased significantly while no changes were detected in the other activities. Subsequently FA synthesis did not change while the activities of the enzymes decreased slowly. These enzymes did not appear to regulate FA synthesis during inhibition of lipogenesis, but FAS, CL or G6PDH may be rate limiting in the induction phase. Other key factors may regulate FA synthesis during dietary alterations

  18. 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...

  19. 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...

  20. 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

  1. Increased Production of Fatty Acids and Triglycerides in Aspergillus oryzae by Enhancing Expressions of Fatty Acid Synthesis-Related Genes

    Energy Technology Data Exchange (ETDEWEB)

    Tamano, Koichi; Bruno, Kenneth S.; Karagiosis, Sue A.; Culley, David E.; Deng, Shuang; Collett, James R.; Umemura, Myco; Koike, Hideaki; Baker, Scott E.; Machida, Masa

    2013-01-01

    Microbial production of fats and oils is being developedas a means of converting biomass to biofuels. Here we investigate enhancing expression of enzymes involved in the production of fatty acids and triglycerides as a means to increase production of these compounds in Aspergillusoryzae. Examination of the A.oryzaegenome demonstrates that it contains twofatty acid synthases and several other genes that are predicted to be part of this biosynthetic pathway. We enhancedthe expressionof fatty acid synthesis-related genes by replacing their promoters with thepromoter fromthe constitutively highly expressedgene tef1. We demonstrate that by simply increasing the expression of the fatty acid synthasegenes we successfullyincreasedtheproduction of fatty acids and triglyceridesby more than two fold. Enhancement of expression of the fatty acid pathway genes ATP-citrate lyase and palmitoyl-ACP thioesteraseincreasedproductivity to a lesser extent.Increasing expression ofacetyl-CoA carboxylase caused no detectable change in fatty acid levels. Increases in message level for each gene were monitored usingquantitative real-time RT-PCR. Our data demonstrates that a simple increase in the abundance of fatty acid synthase genes can increase the detectable amount of fatty acids.

  2. Synthesis of hyper branched polyol from palm oil oleic acid

    International Nuclear Information System (INIS)

    Hyper branched polyol from oleic acid of palm oil has been synthesized by a two-step reaction. Dipentaerythritol was initially reacted with 2, 2-bis (hydroxymethyl) propionic acid in a solution medium aided by p-toluene sulfonic acid as a catalyst. This mixture was then used as core and reacted with the oleic acid. Optimization parameters such as processing temperature and reaction time, and chemical analysis (for example OHV, AV, FTIR, NMR and GPC) of the macromolecule synthesized is presented in this paper. (author)

  3. Synthesis and Performance of N-(Benzoyl) Stearic Acid Hydrazide

    OpenAIRE

    Cai, Yan-Hua; Li, Shun-Jiang

    2012-01-01

    N-(benzoyl) stearic acid hydrazide was synthesized from benzoyl hydrazine and stearyl chloride which was deprived from stearic acid via acylation. The structure of the compound had been characterized by FT-IR, 1H NMR, at the same time, the structure of N-(benzoyl) stearic acid hydrazide was optimized by the semiempirical method PM3. The influence of the reaction ratio, reaction time and reaction temperature to the yield of N-(benzoyl) stearic acid hydrazide was investigated by orthogonal expe...

  4. 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.

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

    International Nuclear Information System (INIS)

    Racemic, R- and S-β-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]-β-hydroxybutyric acid and R- or S-[1-11C]-β-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)

  6. 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

  7. 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 u...

  8. 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...

  9. Synthesis and colloidal properties of polyesters based on glutamic acids and glycols of different nature

    OpenAIRE

    Varvarenko, Sergiy; Tarnavchyk, Ihor; Voronov, Andriy; Fihurka, Nataliia; Dron, Iryna; Nosova, Nataliia; Taras, Roman; Samaryk, Volodymyr; Voronov, Stanislav

    2013-01-01

    The paper describes synthesis and colloidal properties of novel α-amino acid based polyesters with controllable hydrophilic-lipophillic balance. Polyesters based on glutamic acid and glycols of different nature were obtained via low-temperature activated polyesterification. Such polymers are able to form micellar structures in self-stabilized water dispersion. Peculiarities of Steglich rection in the case of polyesterefication and side processes were established and optimal conditions for pol...

  10. Synthesis of branched amino acids : isonorstatine, phenylisothreonine, lactacystin analogues, and amino polyols

    OpenAIRE

    Li, Feng

    2007-01-01

    The 1,2-aminoalcohol fragment is found in many natural products and drugs, for example as a central moiety of non-proteinogenic amino acids. It is also an integral part of doxorubicin and daunomycin, which have been used for the treatment of human malignancies. There is, therefore, a particular interest in the synthesis of branched amino hydroxy acids such as isonorstatine, phenylisothreonine, amino polyols and lactacystin derivatives. Norstatine is part of amastatin, an inhibitor of leuc...

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

    OpenAIRE

    Vanda, D.; Jorda, R. (Radek); Lemrov, B.; Voln, T.; Krytof, V. (Vladimr); 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...

  12. 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...

  13. Synthesis of linoleic acids combinatorially-labeled at the vinylic positions as substrates for lipoxygenases

    OpenAIRE

    Meyer, Matthew P.; Klinman, Judith P.

    2008-01-01

    Mammalian lipoxygenases have been implicated in a number of inflammation-related human diseases. Soybean lipoxygenase-1 is the archetypical example of known lipoxygenases. Here we report the synthesis of linoleic acid and (11,11)-d2-linoleic acid which are combinatorially labeled at the vinylic positions (9, 10, 12, and 13). Combinatorial labeling schemes allow for the simultaneous determination of KIEs in enzymatic reactions using NMR. Substrates are, thus, available as probes of detailed me...

  14. 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

  15. 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-...

  16. 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...... stereoisomers of the bicyclic analogue 5-amino-4,5,6,6a-tetrahydro-3aH-cyclopenta[d]isoxazole-3,5-dicarboxylic acid (+)-2, (-)-2, (+)-3, and (-)-3 were tested at ionotropic and metabotropic glutamate receptor subtypes. The most potent NMDA receptor antagonists [(+)-2, (-)-4, and (+)-5] showed a significant...

  17. 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

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

    International Nuclear Information System (INIS)

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

  19. 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.

  20. 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.

  1. 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

    Roč. 17, č. 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

  2. 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.

  3. (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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Synthesis of an ent-Halimanolide from ent-Halimic Acid

    Directory of Open Access Journals (Sweden)

    Julio G. Urones

    2008-05-01

    Full Text Available An efficient synthesis of ent-halimanolide 2 (15,16-epoxy-12-oxo-ent-halima- 5(10,13(16,14-trien-18,2β-olide, from ent-halimic acid has been achieved, corroborating the structure of the natural compound and establishing its absolute configuration.

  9. Conversion of pollutants to fertilisers: ion exchange synthesis of potassium sulphate from acidic mine waters.

    Science.gov (United States)

    Muraviev, D

    2003-01-01

    The paper reports the results obtained by the development of ion exchange synthesis of K2SO4 from the natural acidic mine waters (AMW) of Rio Tinto area (Huelva, Spain). The process flowsheet includes several sequential stages permitting production of potassium sulphate and desalinated water along with the recovery of four metals. PMID:12926638

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

    OpenAIRE

    S. A. M. SHEDID; H. M. HASSAN

    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.

  11. 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)

  12. 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

  13. Enantioselective Total Synthesis of Lycoposerramine-Z Using Chiral Phosphoric Acid Catalyzed Intramolecular Michael Addition.

    Science.gov (United States)

    Zhang, Lan-De; Zhong, Lin-Rui; Xi, Jie; Yang, Xiao-Liang; Yao, Zhu-Jun

    2016-03-01

    A new enantioselective total synthesis of phlegmarine-type Lycopodium alkaloid lycoposerramine-Z (1) has been accomplished, using one-pot chemoselective sequential additions of two different Grignard reagents to the bis-Weinreb-amide intermediate and an efficient construction of the fully fuctionalized cyclohexanone intermediate with a chiral phosphoric acid catalyzed enantioselective intramolecular Michael addition. PMID:26871307

  14. Synthesis of 3-[3H]-5-(4'-azobenzene arsonic acid)-L-tyrosine

    International Nuclear Information System (INIS)

    The title compound (ABA-Tyr) was prepared by direct radiochemical synthesis from tritiated tert.-butoxycarbonyl-L-tyrosine and diazotised arsanilic acid followed by acidolytic deprotection and isolation by preparative high pressure liquid chromatography. The product had a specific activity of 9 Ci mmol-1 and a radiochemical purity of 90-95%. (author)

  15. Synthesis of polyacrylic-acid-based thermochromic polymers

    Science.gov (United States)

    Srivastava, Jyoti; Alam, Sarfaraz; Mathur, G. N.

    2003-10-01

    Smart materials respond to environmental stimuli with particular changes in some variables (for example temperature, pressure and electric field etc), for that reason they are often called responsive materials. In the present work, we have synthesized thermochromic polymer based on poly acrylic acid cobalt chloride (CoCl2) and phosphoric acid (H3PO4) that visually and reversibly changes color in the temperature range (70 - 130°C). These thermochromic materials can be used as visual sensors of temperature. Thermochromic polymers are based on polyacrylic acid and CoCl2 complex.

  16. Synthesis and biological evaluation of novel lipoamino acid derivatives.

    Science.gov (United States)

    Kaki, Shiva Shanker; Arukali, Sammaiah; Korlipara, Padmaja V; Prasad, R B N; Yedla, Poornachandra; Ganesh Kumar, C

    2016-01-01

    Seven novel lipoamino acid conjugates were synthesized from methyl oleate and amino acids. Methyl oleate was grafted to different amino acids using thioglycolic acid as a spacer group. Seven derivatives (3a-g) were prepared and characterized by spectral data (NMR, IR and MS spectral studies). All the derivatives were studied for their antimicrobial, anti-biofilm and anticancer activities. Among all the derivatives, it was found that compound 3b was the most potent antibacterial compound which showed good activity against four Gram positive bacterial strains and also exhibited excellent antifungal activity against a fungal strain. In the anti-biofilm assay, compound 3b showed promising activity with IC50 value of 2.8μM against Bacillus subtilis MTCC 121. All the compounds showed anticancer activities with 3c showing promising anticancer activity (IC50=15.3-22.4μM) against the four cell lines tested. PMID:26586599

  17. 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

  18. Design, synthesis and biological evaluation of novel betulinic acid derivatives

    OpenAIRE

    Yang Shengjie; Liang Na; Li Hu; Xue Wei; Hu Deyu; Jin Linhong; Zhao Qi; Yang Song

    2012-01-01

    Abstract Background Tumor, is one of the major reason for human death, due to its widespread occurrence. Betulinic acid derivatives have attracted considerable attention as cancer chemopreventive agents and also as cancer therapeutics. Many of its derivatives inhibit the growth of human cancer cell lines by triggering apoptosis. With this background, we planned to synthesize a series of betulinic acid derivatives to assess their antiproliferation efficacy on human cancer cell lines. Results A...

  19. SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF OXIME ESTERS FROM DIHYDROCUMIC ACID

    OpenAIRE

    Yanqing Gao,; Jie Song,; Shibin Shang; Dan Wang; Jian Li

    2012-01-01

    Dihydrocumic acid was prepared from β-pinene through oxidation and dehydration. Then, ten oxime esters from dihydrocumic acid were synthesized. Reaction conditions of the oxime esters were adjusted and their structures were characterized by IR, 1H-NMR, MS, and elemental analysis. The antibacterial activity of these newly synthesized oxime esters against Gram-negative bacteria and Gram-positive bacteria was also investigated using the inhibition zone method. The preliminary results indicated t...

  20. Facile Synthesis of Oleanolic Acid Monoglycosides and Diglycosides

    OpenAIRE

    Mao-Sheng Cheng; Yang Liu; Jiao Liu; Mao-Cai Yan; Yu Sha

    2008-01-01

    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 di...

  1. 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)

  2. The synthesis of barbituric acid and some of its derivatives isotopically labelled with 15N

    International Nuclear Information System (INIS)

    Full text: Barbituric acid is the parent compound of a large class of barbiturates that have central nervous system depressant properties, although barbituric acid itself is not pharmacologically active. In recent years, barbituric acid derivatives have been studied as antitumor, anticancer and anti-osteoporosis agents. The aim of this paper is to present the synthesis of barbituric acid-15N, 5,5-diethylbarbituric acid-15N (Veronal-15N) and 5-ethyl-5-phenylbarbituric acid- 15N (Phenobarbitone-15N) . As isotopically labelled material we used urea-15N2, 99 at.% 15N produced at National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania. All compounds were fully characterized by Mass Spectrometry analyses, by FT-IR Spectroscopy and RX Diffraction, and the isotopic label was determined by MS on the molecular compounds. (author)

  3. Synthesis, biological distribution and radiation dosimetry of Te-123m analogues of hexadecenoic acid

    International Nuclear Information System (INIS)

    The synthesis and biological distribution of four Te-123m analogues of hexadecenoic acid in rats, rabbits and dogs were described for use as possible myocardial imaging agents. The heart-to-blood ratios ranged from 0.13 for 3-telluranonadecenoic acid in rats at 5 mins to 6.25 for 18-methyl-17-tellura-9-nonadecenoic acid in dogs at 24 hrs. The biological half-life of the Te-123m labelled fatty acids ranged from 26 to 583 hrs in the hearts of the test animals. These Te-123m fatty acids were retained in the heart longer than radioiodinated fatty acids and have acceptable absorbed doses to the various target organs. (U.K.)

  4. 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.

  5. Synthesis of N,N-Bis(nonaflyl) Squaric Acid Diamide and its Application to Organic Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cheon, Cheol Hong; Yamamoto, Hisashi [The Univ. of Chicago, Chicago (United States)

    2010-03-15

    We have developed a new strong Brφnsted acid bearing two nonaflyl groups based on the squaric acid scaffold. The Brφnsted acid 2 showed the almost same reactivity as bistriflyl squaramide 1 in Mukaiyama aldol and Michael reactions of benzaldehyde with silyl enol ether. Moreover, the utility of Brφnsted acid 2 could be expanded to carbonyl ene reaction of rac-citronellal. Further application of this new Brφnsted acid to organic reactions and to flow system reactors is currently underway in our laboratory. Brφnsted acid catalysis is one of the growing fields in modern organic synthesis.1 Although several Brφnsted acids, such as urea/thiourea, TADDOL, and phosphoric acid, have been applied to a variety of organic reactions, other Brφnsted acid scaffolds have been much less explored. Recently, Rawal et al have developed a Brφnsted acid catalyst based on squaric acid moiety and successfully applied it as a catalyst for conjugate addition of 1,3-dicarbonyl compounds to nitroolefins. More recently, we have developed a strong Brφnsted acid derived from squaric acid by introducing a strong electron withdrawing trifluoromethanesulfonyl (Tf) group and applied it to Mukaiyama aldol and Michael reaction of a variety of aldehydes, ketones, and α,β-unsaturated ketones. As a continuing effort to develop strong Brφnsted acids based on the squaric acid scaffold, it was expected that replacement of Tf group with a longer perfluoro-alkanesulfonyl group would be able to tune the physical properties, such as solubilities in organic solvents and fluoro-philicity, without loss of reactivity. Herein, we report the development of a new Brφnsted acid based on the squaric acid scaffold carrying two nonafluorobutanesulfonyl (Nf) groups and the preliminary results of its reactivity to various organic reactions.

  6. 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.

  7. 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.

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

    International Nuclear Information System (INIS)

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

  9. Magnetic, acidic, ionic liquid-catalyzed one-pot synthesis of spirooxindoles.

    Science.gov (United States)

    Khalafi-Nezhad, Ali; Mohammadi, Somayeh

    2013-09-01

    Magnetic, supported, acidic ionic liquid was synthesized and identified as an efficient catalyst for the one-pot synthesis of novel spirooxindole derivatives at mild conditions and in good yields. Three component reaction of wide variety of substituted isatins, 1,3-dimethyl-2-amino uracil, and barbituric acid, thiobarbituric acid, and dimedon as 1,3-dicarbonyl compounds gives the target compounds. Operational simplicity, low cost, high yields, environmental friendliness, wide applicability and reusability and easy recovery of the catalyst using an external magnet are the key features of this methodology. PMID:23971413

  10. [Synthesis and Anticancer Activity of Betulonic Acid Imidazolides].

    Science.gov (United States)

    Kazakova, O B; Medvedeva, N I; Lopatina, T V; Apryshko, G N; Pugacheva, R B; Yavorskaya, N P; Golubeva, I S; Tolstikov, G A

    2015-01-01

    Synthesis of lupane C28-imidazolides, contained 3-oxo-, 3-oximino- and 2-cyano-2,3-seco-4(23)-en-frag ments in cycle A was carried out. The most antitumor activity at. in vitro testing showed 3-oximino-lup- 20(29)-en-28-yl-1H-imidazole-1-carboxylate; which inhibited the growth or induced apoptosis of non-small lung cancer, colon cancer, breast cancer, CNS cancer, ovarian cancer, prostate cancer, leucosis, melanoma cells. In experiments in mice its moderate antitumor activity against grafted breast adenocarcinoma Ca 755 and adenocarcinima of colon was observed. PMID:26502611

  11. 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 β 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 ω 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

  12. Trans-10, cis-12 conjugated linoleic acid decreases de novo lipid synthesis in human adipocytes

    DEFF Research Database (Denmark)

    Obsen, Thomas; Faergeman, Nils J; Chung, Soonkyu; Martinez, Kristina; Gobern, Semone; Loreau, Olivier; Wabitsch, Martin; Mandrup, Susanne; McIntosh, Michael

    2012-01-01

    [(14)C]-linoleic acids. When using [(14)C]-acetic acid and [(14)C]-pyruvic acid as substrates, 30 μM 10,12 CLA, but not 9,11 CLA, decreased de novo synthesis of triglyceride, free FA, diacylglycerol, cholesterol esters, cardiolipin, phospholipids and ceramides within 3-24 h. Treatment with 30 μM 10...... 7-12 h, respectively. The mRNA levels of liver X receptor (LXR)α and sterol regulatory element binding protein (SREBP)-1c, transcription factors that regulate SCD-1, were decreased by 10,12 CLA within 5 h. These data suggest that the isomer-specific decrease in de novo lipid synthesis by 10,12 CLA...

  13. Labeling and imaging study of fatty acid analogue 18F-FHTA on domestic synthesis module

    International Nuclear Information System (INIS)

    18F-6-thia-14-fluoroheptadecanoic acid (18F-FTHA), a free fatty acid, has been used in myocardial PET imaging. In order to establish an automated synthesis module for routine production, a study was performed on domestic synthesis module. Methods: 18F- FTHA was prepared from Benzyl-14-tosyloxy-6-thia-heptadecanoate as precursor. Biodistribution studies in the NH rats and Micro-PET/CT imaging studies in the SD rat were performed. The results showed that total synthesis time was about 50 minutes and the uncorrected synthesis yield was 10.6%, radiochemical purity was higher than 99%, the product had good stability at room temperature. Biodistribution data in rats showed the uptake of heart was 19.04 ID%/g at 60 minutes, heart-to-liver ratios at 60 and 90 min were 6.4 and 3.2, respectively. Micro-PET/CT imaging of the SD rat showed intense cardiac uptake. Conclusions: Using this procedure a fast, reliable. automated synthesis for the myocardial PET tracer, 18F-FTHA, can be obtained. (authors)

  14. 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

  15. 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)

  16. 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.

  17. 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.

  18. One-Pot synthesis of phosphorylated mesoporous carbon heterogeneous catalysts with tailored surface acidity

    Energy Technology Data Exchange (ETDEWEB)

    Fulvio, Pasquale F [ORNL; Mahurin, Shannon Mark [ORNL; Mayes, Richard T [ORNL; Bauer, Christopher [ORNL; Wang, Xiqing [ORNL; Veith, Gabriel M [ORNL; Dai, Sheng [ORNL

    2012-01-01

    Soft-templated phosphorylated mesoporous carbons with homogeneous distributions of phosphate groups were prepared by a 'one-pot' synthesis method using mixtures of phosphoric acid with hydrochloric, or nitric acids in the presence of Pluronic F127 triblock copolymer. Adjusting the various ratios of phosphoric acid used in these mixtures resulted in carbons with distinct adsorption, structural and surface acidity properties. The pore size distributions (PSDs) from nitrogen adsorption at -196 C showed that mesoporous carbons exhibit specific surface areas as high as 551 m{sup 2}/g and mesopores as large as 13 nm. Both structural ordering of the mesopores and the final phosphate contents were strongly dependent on the ratios of H{sub 3}PO{sub 4} in the synthesis gels, as shown by transmission electron microscopy (TEM), X-ray photoelectron (XPS) and energy dispersive X-ray spectroscopy (EDS). The number of surface acid sites determined from temperature programmed desorption of ammonia (NH{sub 3}-TPD) were in the range of 0.3-1.5 mmol/g while the active surface areas are estimated to comprise 5-54% of the total surface areas. Finally, the conversion temperatures for the isopropanol dehydration were lowered by as much as 100 C by transitioning from the least acidic to the most acidic catalysts surface.

  19. 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.

  20. 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

  1. 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

  2. Prolinol-based nucleoside phosphonic acids: Synthesis and properties

    Czech Academy of Sciences Publication Activity Database

    Vaněk, Václav; Buděšínský, Miloš; Liboska, Radek; Hurychová, Vladimíra; Rosenberg, Ivan

    -, č. 52 (2008), s. 537-538. ISSN 0261-3166. [Joint Symposium of the International Roundtable on Nucleosides, Nucleotides and Nucleic Acids /18./ and the International Symposium on Nucleic Acid Chemistry /35./. Kyoto, 08.09.2008-12.09.2008] R&D Projects: GA MŠk(CZ) LC06061; GA MŠk(CZ) LC06077; GA MŠk LC512 Institutional research plan: CEZ:AV0Z40550506 Keywords : oligonucleotide phosphonate * nucleoside analogue * pyrrolidine * prolinol Subject RIV: CC - Organic Chemistry

  3. 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

  4. SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF OXIME ESTERS FROM DIHYDROCUMIC ACID

    Directory of Open Access Journals (Sweden)

    Yanqing Gao,

    2012-07-01

    Full Text Available Dihydrocumic acid was prepared from β-pinene through oxidation and dehydration. Then, ten oxime esters from dihydrocumic acid were synthesized. Reaction conditions of the oxime esters were adjusted and their structures were characterized by IR, 1H-NMR, MS, and elemental analysis. The antibacterial activity of these newly synthesized oxime esters against Gram-negative bacteria and Gram-positive bacteria was also investigated using the inhibition zone method. The preliminary results indicated that seven compounds displayed better antibacterial activity against Gram-negative bacteria compared with bromogeramine, a commercially available antibacterial agent.

  5. 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.

  6. The promoting effects of geniposidic acid and aucubin in Eucommia ulmoides Oliver leaves on collagen synthesis.

    Science.gov (United States)

    Li, Y; Sato, T; Metori, K; Koike, K; Che, Q M; Takahashi, S

    1998-12-01

    We have reported that collagen synthesis was stimulated by the administration of a hot water extract from the leaves of Eucommia ulmoides OLIVER, Eucommiaceae (Du-Zhong leaves) in false aged model rats. In this paper, we set out to examine the compounds in Du-Zhong leaves that stimulated collagen synthesis in false aged model rats. In experiment 1, a methanol extract of Du-Zhong leaves also stimulated collagen synthesis in aged model rats. An acetone fraction was derived from the methanol extract by silica gel chromatography in experiment 2. The acetone fraction mainly contained iridoides mono-glycosides such as geniposidic acid and aucubin. The administration of geniposidic acid or aucubin stimulated collagen synthesis in aged model rats in experiments 3 and 4 (significance (p<0.05)). The reported pharmacological effects of Du-Zhong leaves, including healing organs and strengthening bone and muscle, are closely related to collagen metabolism. It appears that geniposidic acid and aucubin are the actual compounds in Du-Zhong which caused the effect in our experiments. PMID:9881644

  7. Synthesis of dopamine analogue containing benzeneboronic acid group, a target compound for BNCT

    International Nuclear Information System (INIS)

    Melanin synthesis is accentuated in the melanoma cells. DOPA is one of the melanin precursors, and has been found to be the substrates for tyrosinase. Since Dopamine has the similar structure to DOPA, we have thought that the Dopamine containing boron atom has a possibility to be incorporated into the melanin synthesis pathway, resulting in both higher 10B-delivery and long lasting 10B-accumulation in melanoma. Thus, we tried to synthesize a new amide compound between Dopamine and p-carboxybenzeneboronic acid (PCBA). (author)

  8. Synthesis of dopamine analogue containing benzeneboronic acid group, a target compound for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, T.; Yoshino, K. [Shinshu Univ., Faculty of Science, Matsumoto, Nagano (Japan); Hiratsuka, J. [Kawasaki Medical School, Dept. of Radiation Oncology, Kurashiki, Okayama (Japan); Ichihashi, M. [Kobe Univ. (Japan). School of Medicine

    2000-10-01

    Melanin synthesis is accentuated in the melanoma cells. DOPA is one of the melanin precursors, and has been found to be the substrates for tyrosinase. Since Dopamine has the similar structure to DOPA, we have thought that the Dopamine containing boron atom has a possibility to be incorporated into the melanin synthesis pathway, resulting in both higher {sup 10}B-delivery and long lasting {sup 10}B-accumulation in melanoma. Thus, we tried to synthesize a new amide compound between Dopamine and p-carboxybenzeneboronic acid (PCBA). (author)

  9. Ultraviolet induction of prophage lambda during inhibition of deoxyribonucleic acid synthesis by hydroxyurea

    International Nuclear Information System (INIS)

    Hydroxyurea inhibited synthesis of certain deoxyribonucleic acid (DNA) precursors and caused the cessation of DNA synthesis. It did not cause induction of lambda. Superinfection of an irradiated lysogen with lambda ind- could prevent induction, but the percentage of cells protected decreased as the time between irradiation and superinfection increased. The presence of hydroxyurea did not increase the time during which cells could be rescued by superinfection. The accumulation of DNA precursors after ultraviolet or ionizing radiation was not necessary for the induction of lambda prophage to occur

  10. Early signal transduction linking the synthesis of jasmonic acid in plant.

    Science.gov (United States)

    Hu, Xiangyang; Li, Wansha; Chen, Qi; Yang, Yongping

    2009-08-01

    Jasmonate signaling plays a critical role in protecting plants from pathogens or insect attacks and in limiting damage from abiotic stress. Many events contribute to the regulation of jasmonic acid (JA) synthesis during abiotic or biotic stress, but the details of the underlying mechanism remain unclear. In this Mini-Review paper, we discuss the possible roles of reactive oxygen species (ROS), nitric oxide (NO), calcium influx and mitogen-activated protein kinase (MAPK) cascade during JA synthesis or JA signal transduction. PMID:19820318

  11. 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.

  12. 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.

  13. Automated synthesis of 11C-acetoacetic acid, a key alternate brain fuel to glucose

    International Nuclear Information System (INIS)

    An automated, one-pot radio-synthesis module for the routine preparation of 1-[11C]acetoacetic acid has been developed. The enolate anion of acetone was reacted with [11C]CO2 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

  14. 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.

  15. Design, synthesis and biological evaluation of novel betulinic acid derivatives

    Directory of Open Access Journals (Sweden)

    Yang Shengjie

    2012-11-01

    Full Text Available Abstract Background Tumor, is one of the major reason for human death, due to its widespread occurrence. Betulinic acid derivatives have attracted considerable attention as cancer chemopreventive agents and also as cancer therapeutics. Many of its derivatives inhibit the growth of human cancer cell lines by triggering apoptosis. With this background, we planned to synthesize a series of betulinic acid derivatives to assess their antiproliferation efficacy on human cancer cell lines. Results A series of novel betulinic acid derivatives were designed and synthesized as highlighted by the preliminary antitumor evaluation against MGC-803, PC3, A375, Bcap-37 and A431 human cancer cell lines in vitro. The pharmacological results showed that some of the compounds displayed moderate to high levels of antitumor activities with most of new exhibiting higher inhibitory activities compared to BA. The IC50 values of compound 3c on the five cancer cell lines were 2.3, 4.6, 3.3, 3.6, and 4.3 μM, respectively. Subsequent fluorescence staining and flow cytometry analysis (FCM indicated that compound 3c could induce apoptosis in MGC-803 and PC3 cell lines, and the apoptosis ratios reached the peak (37.38% and 33.74% after 36 h of treatment at 10 μM. Conclusions This study suggests that most of betulinic acid derivatives could inhibit the growth of human cancer cell lines. Furthermore, compound 3c could induce apoptosis of cancer cells.

  16. 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.

  17. Exploring the Potential of Fungal Arylacetonitrilases in Mandelic Acid Synthesis

    Czech Academy of Sciences Publication Activity Database

    Veselá, Alicja Barbara; Křenková, Alena; Martínková, Ludmila

    2015-01-01

    Roč. 57, č. 5 (2015), s. 466-474. ISSN 1073-6085 R&D Projects: GA ČR(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

  18. Synthesis of Borinic Acids and Borinate Adducts Using Diisopropylaminoborane.

    Science.gov (United States)

    Marciasini, Ludovic; Cacciuttolo, Bastien; Vaultier, Michel; Pucheault, Mathieu

    2015-07-17

    In situ formation of aryl Grignard under Barbier condition and diisopropylaminoborane as boron source allows a complete control of the addition onto the boron electrophile. Analytically pure borinic acid derivatives were produced at the gram scale without column chromatography and isolated as borinates adducts, with ethanolamine or 8-hydroxyquinoline, after workup. PMID:26183591

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  20. 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 ...

  1. Hypercrosslinked polystyrene sulphonic acid catalysts for the esterification of free fatty acids in biodiesel synthesis

    OpenAIRE

    Andrijanto, E.; Dawson, E.A.; Brown, D.R.

    2012-01-01

    New sulphonic acid catalysts supported on hypercrosslinked polystyrene have been studied in the esterification of oleic acid with methanol and in the rearrangement of α-pinene to camphene and limonenes. The catalysts have been characterised in terms of specific surface areas and porosities, affinities for water and for cylcohexane vapours, and both concentrations and strengths of acid sites. They have been compared with conventional macroporous polystyrene sulphonic acids (Amberlysts 15 and 3...

  2. 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...

  3. Synthesis of acetic acid via methanol hydrocarboxylation with CO2 and H2.

    Science.gov (United States)

    Qian, Qingli; Zhang, Jingjing; Cui, Meng; Han, Buxing

    2016-01-01

    Acetic acid is an important bulk chemical that is currently produced via methanol carbonylation using fossil based CO. Synthesis of acetic acid from the renewable and cheap CO2 is of great importance, but state of the art routes encounter difficulties, especially in reaction selectivity and activity. Here we report a route to produce acetic acid from CO2, methanol and H2. The reaction can be efficiently catalysed by Ru-Rh bimetallic catalyst using imidazole as the ligand and LiI as the promoter in 1,3-dimethyl-2-imidazolidinone (DMI) solvent. It is confirmed that methanol is hydrocarboxylated into acetic acid by CO2 and H2, which accounts for the outstanding reaction results. The reaction mechanism is proposed based on the control experiments. The strategy opens a new way for acetic acid production and CO2 transformation, and represents a significant progress in synthetic chemistry. PMID:27165850

  4. 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.

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

    DEFF Research Database (Denmark)

    Meyhoff, Ulrich; Riber, Ulla; Boas, Ulrik

    2015-01-01

    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 μg mL-1.......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...

  6. 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

  7. Synthesis and curing of alkyd enamels based on ricinoleic acid

    Directory of Open Access Journals (Sweden)

    Jovičić 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.

  8. [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

  9. Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

    OpenAIRE

    Best, Daniel; Burns, David J.; Lam, Hon Wai

    2015-01-01

    A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor.

  10. Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

    Science.gov (United States)

    Best, Daniel; Burns, David J; Lam, Hon Wai

    2015-01-01

    A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

  11. Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds.

    Science.gov (United States)

    Best, Daniel; Burns, David J; Lam, Hon Wai

    2015-06-15

    A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N-H groups are tolerated on the barbituric acid, with no complications arising from N-H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

  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. 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

  14. Synthesis of Bioconjugate Sesterterpenoids with Phospholipids and Polyunsaturated Fatty Acids.

    Science.gov (United States)

    Gil-Mesón, Ana; Roncero, Alejandro M; Tobal, Ignacio E; Basabe, Pilar; Díez, David; Mollinedo, Faustino; Marcos, Isidro S

    2015-01-01

    A series of sesterterpenoid bioconjugates with phospholipids and polyunsaturated fatty acids (PUFAs) have been synthesized for biological activity testing as antiproliferative agents in several cancer cell lines. Different substitution analogues of the original lipidic ether edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) are obtained varying the sesterterpenoid in position 1 or 2 of the glycerol or a phosphocholine or PUFA unit in position 3. Simple bioconjugates of sesterterpenoids and eicosapentaenoic acid (EPA) have been obtained too. All synthetic derivatives were tested against the human tumour cell lines HeLa (cervix) and MCF-7 (breast). Some compounds showed good IC50 (0.3 and 0.2 μM) values against these cell lines. PMID:26729084

  15. Synthesis of Bioconjugate Sesterterpenoids with Phospholipids and Polyunsaturated Fatty Acids

    Directory of Open Access Journals (Sweden)

    Ana Gil-Mesón

    2015-12-01

    Full Text Available A series of sesterterpenoid bioconjugates with phospholipids and polyunsaturated fatty acids (PUFAs have been synthesized for biological activity testing as antiproliferative agents in several cancer cell lines. Different substitution analogues of the original lipidic ether edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine are obtained varying the sesterterpenoid in position 1 or 2 of the glycerol or a phosphocholine or PUFA unit in position 3. Simple bioconjugates of sesterterpenoids and eicosapentaenoic acid (EPA have been obtained too. All synthetic derivatives were tested against the human tumour cell lines HeLa (cervix and MCF-7 (breast. Some compounds showed good IC50 (0.3 and 0.2 μM values against these cell lines.

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

    Directory of Open Access Journals (Sweden)

    M. Shahrom

    2014-01-01

    Full Text Available Ionic Liquids (ILs are organic salts with low melting points (below 100°C and have been widely promoted as “green solvents” due to their non volatility which results in low impact on the environment and health. Natural occurring amino acids, which are easily obtained, biocompatible and biodegradable, are considered as alternative anions for ILs. Four Amino Acids Ionic Liquids (AAILs have been synthesized by using 4-vinylbenzyltrimethylammonium, [VBTMA] as the cation and glycine, alanine, serine and proline as the anions. The ILs were characterized by Nuclear Magnetic Resonance (NMR and Fourier Transform Infrared Spectroscopy (FTIR. The thermal degradation behavior was measured by Thermogravimetric Analysis (TGA and glass transition temperature measured by Differential Scanning Coulometry (DSC. The result showed that VBTMA Pro gives the highest thermal stability with 178.29°C.

  17. Electrolytic Synthesis of Benzoic Anhydride from Benzoic Acid

    OpenAIRE

    Takahashi, Takeshige; KAMADA, Mitsushi; タカハシ, タケシゲ; カマダ, ミツシ; 高橋, 武重; 鎌田, 三司

    1982-01-01

    Electrolysis of benzoic acid was investigated by means of controlled current operation in acetonitrile with platinum disk electrodes. Benzoic anhydride was obtained from an anolyte at 20-30% of current efficiency as one electron reaction. At the same time, acetamide and hydrogen perchlorate were obtained from the anolyte, and triethylamine was obtained from the catholyte. The yield of acetamide was nearly equal to benzoic anhydride. On the other hand, the yield of triethylamine ap...

  18. Synthesis and Characterization of Hybrid Hyaluronic Acid-Gelatin Hydrogels

    OpenAIRE

    Camci-Unal, Gulden; Cuttica, Davide; Annabi, Nasim; Demarchi, Danilo; Khademhosseini, Ali

    2013-01-01

    Biomimetic hybrid hydrogels have generated broad interest in tissue engineering and regenerative medicine. Hyaluronic acid (HA) and gelatin (hydrolyzed collagen) are naturally derived polymers and biodegradable under physiological conditions. Moreover, collagen and HA are major components of the extracellular matrix (ECM) in most of the tissues (e.g. cardiovascular, cartilage, neural). When used as a hybrid material, HA-gelatin hydrogels may enable mimicking the ECM of native tissues. Althoug...

  19. Synthesis and acid resistance of maya blue pigment

    OpenAIRE

    Sanchez Del Rio, Manolo; Martinetto, Pauline; Reyes-Valerio, C.; Dooryhee, Eric; Suarez, M. (Manuel)

    2012-01-01

    Maya blue is an organo-clay artificial pigment composed of indigo and palygorskite. It was invented and frequently used in Mesoamerica in ancient times (eighth to 16th centuries). We analyse in this paper one of the characteristics of Maya blue that has attracted the attention of scientists since its rediscovery in 1931: its high stability against chemical aggression (acids, alkalis, solvents, etc.) and biodegradation, which has permitted the survival of many works of art for centuries in hos...

  20. 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, Jzef

    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

  1. 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  |

  2. Synthesis and characterization of fatty hydroxamic acids from triacylglycerides.

    Science.gov (United States)

    Hoidy, Wisam H; Ahmad, Mansor B; Al-Mulla, Emad A Jaffar; Yunus, Wan Md Zin Wan; Ibrahim, Nor azowa Bt

    2010-01-01

    In this study, fatty haydroxamic acids (FHAs), which have biological activities as antibiotics and antifungal, have been synthesized via refluxing of triacylglycrides, palm olein, palm stearin or corn oil with hydroxylamine hydrochloride. The products were characterized using the complex formation test of hydroxamic acid group with zinc(I), copper(II) and iron(III), various technique methods including nuclear magnetic resonance ((1)H NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and elemental analysis. Parameters that may affect the conversion of oils to FHAs including the effect of reaction time, effect of organic solvent and effect of hydro/oil molar issue were also investigated in this study. Results of characterization indicate that FHAs were successfully produced from triacylglycrides. The conversion percentages of palm stearin, palm olein and corn oil into their fatty hydroxamic acids are 82, 81 and 78, respectively. Results also showed that hexane is the best organic solvent to produce the FHAs from the three oils used in this study. The optimum reaction time to achieve the maximum conversion percentage of the oils to FHAs was found to be 10 hours for all the three oils, while the optimum molar ration of hydro/to oil was found to be 7:1 for all the different three oils. PMID:20032595

  3. 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)

  4. Fibre labelling. Polytrimethylene terephthalate - PTT - DuPont: Final report

    OpenAIRE

    PICCININI Paola; SENALDI Chiara; ALBERTO LOPES JOÃO FILIPE

    2014-01-01

    In 2011 DG Enterprise and Industry requested the European Commission’s DG-JRC to technical evaluate a petition submitted by E. I. du Pont de Nemours and Company (DuPont). This petition requested the creation of a new generic fibre name under the Directive 2008/121/EC on textile names, now repealed by the EU Regulation 1007/2011. This would allow distinguishing between their fibre, polytrimethylene terephthalate (PTT) and, in particular, polyethylene terephthalate (PET) and polybutylene tereph...

  5. 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)

  6. Nucleic acid and protein synthesis during lateral root initiation in Marsilea quadrifolia (Marsileaceae)

    Science.gov (United States)

    Lin, B. L.; Raghavan, V.

    1991-01-01

    The pattern of DNA, RNA, and protein synthesis during lateral root initiation in Marsilea quadrifolia L. was monitored by autoradiography of incorporated of 3H-thymidine, 3H-uridine, and 3H-leucine, respectively. DNA synthesis was associated with the enlargement of the lateral root initial prior to its division. Consistent with histological studies, derivatives of the lateral root initial as well as the cells of the adjacent inner cortex and pericycle of the parent root also continued to synthesize DNA. RNA and protein synthetic activities were found to be higher in the lateral root initials than in the endodermal initials of the same longitudinal layer. The data suggest a role for nucleic acid and protein synthesis during cytodifferentiation of a potential endodermal cell into a lateral root initial.

  7. 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

  8. 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

  9. 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.

  10. Study on Synthesis, Characterization and Antiproliferative Activity of Novel Diisopropylphenyl Esters of Selected Fatty Acids.

    Science.gov (United States)

    Reddy, Yasa Sathyam; Kaki, Shiva Shanker; Rao, Bala Bhaskara; Jain, Nishant; Vijayalakshmi, Penumarthy

    2016-01-01

    The present study describes the synthesis, characterization and evaluation of antiproliferative activity of novel diisopropylphenyl esters of alpha-linolenic acid (ALA), valproic acid (VA), butyric acid (BA) and 2-ethylhexanoic acid (2-EHA). These esters were chemically synthesized by the esterification of fatty acids with 2,6-diisopropylphenol and 2,4-diisopropylphenol (propofol). The structure of new conjugates viz. propofol-(alpha-linolenic acid) (2,6P-ALA and 2,4P-ALA), propofol-valproic acid (2,6P-VA and 2,4P-VA), propofol-butyric acid (2,6P-BA and 2,4P-BA) and propofol-(2-ethylhexanoic acid) (2,6P2-EHA and 2,4P-2-EHA) were characterized by FT-IR, NMR ((1)H, (13)C) and mass spectral data. The synthesized conjugates having more lipophilic character were tested for antiproliferative in vitro studies on A549, MDA-MB-231, HeLa, Mia-Pa-Ca and HePG2 cancer cell lines. All the conjugates showed specific growth inhibition on studied cancer cell lines. Among the synthesized esters, the conjugates synthesized from BA, VA and 2-EHA exhibited prominent growth inhibition against A549, HeLa, Mia-Pa-Ca and HePG2 cancer cell lines. The preliminary results suggest that the entire novel conjugates possess antiproliferative properties that reduce the proliferation of cancer cells in vitro. PMID:26666272

  11. 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.

  12. Synthesis of labelled compound of ferulic acid and caffeic acid with tritium

    International Nuclear Information System (INIS)

    Effective components of Chinese traditional herbs consist of many compounds, but some of the compounds usually contain unsaturated carbon-carbon double bonds. The unsaturated organic compounds 3H-Ferulic acid and 3H-Caffeic acid are prepared with their tritiated intermediates made by electric-dischange exposure method, which ensures the compounds contaning double bonds not hydrogenated. The 3H-Ferulic acid is composed of 3H-vanillin and Malonic acid. The 3H-Caffeic acid is composed of 3H-protocatechuyl aldehyde and Malonic acid and the specific activity of the products is 0.2 mCi/mg. The radiochemicaly purity is greater than 90%

  13. 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.

  14. 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)

  15. Benzothiazole incorporated barbituric acid derivatives: synthesis and anticonvulsant screening.

    Science.gov (United States)

    Siddiqui, Nadeem; Ahsan, Waquar

    2009-08-01

    A series of 1-(6-substituted-1,3-benzothiazol-2-yl)-3-(substituted phenyl)hexahydro-2,4,6-pyrimidinetriones 4a-t were synthesized starting from substituted anilines. These compounds contained two active anticonvulsant pharmacophores, benzothiazole and barbituric acid. Structures of the compounds were confirmed on the basis of different spectroscopic techniques. All the compounds were evaluated for their anticonvulsant activity. Three compounds 4c, 4d, and 4s showed promising anticonvulsant activities in Maximal Electroshock Seizure test (MES) and subcutaneous pentylenetetrazole test (scPTZ). They also displayed a wide safety profile when tested for the minimal motor impairment test. PMID:19565603

  16. 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.

  17. Synthesis of kojic acid derivatives as secondary binding site probes of D-amino acid oxidase

    Science.gov (United States)

    Raje, Mithun; Hin, Niyada; Duvall, Bridget; Ferraris, Dana V.; Berry, James F.; Thomas, Ajit G.; Alt, Jesse; Rojas, Camilo; Slusher, Barbara S.; Tsukamoto, Takashi

    2013-01-01

    A series of kojic acid (5-hydroxy-2-hydroxymethyl-4H-pyran-4-one) derivatives were synthesized and tested for their ability to inhibit D-amino acid oxidase (DAAO). Various substituents were incorporated into kojic acid at its 2-hydroxymethyl group. These analogs serve as useful molecular probes to explore the secondary binding site, which can be exploited in designing more potent DAAO inhibitors. PMID:23683589

  18. Rheb-TOR signaling promotes protein synthesis, but not glucose or amino acid import, in Drosophila

    Directory of Open Access Journals (Sweden)

    de la Cruz Aida

    2007-03-01

    Full Text Available Abstract Background The Ras-related GTPase, Rheb, regulates the growth of animal cells. Genetic and biochemical tests place Rheb upstream of the target of rapamycin (TOR protein kinase, and downstream of the tuberous sclerosis complex (TSC1/TSC2 and the insulin-signaling pathway. TOR activity is regulated by nutritional cues, suggesting that Rheb might either control, or respond to, nutrient availability. Results We show that Rheb and TOR do not promote the import of glucose, bulk amino acids, or arginine in Drosophila S2 cells, but that both gene products are important regulators of ribosome biogenesis, protein synthesis, and cell size. S2 cell size, protein synthesis, and glucose import were largely insensitive to manipulations of insulin signaling components, suggesting that cellular energy levels and TOR activity can be maintained through insulin/PI3K-independent mechanisms in S2 cell culture. In vivo in Drosophila larvae, however, we found that insulin signaling can regulate protein synthesis, and thus may affect TOR activity. Conclusion Rheb-TOR signaling controls S2 cell growth by promoting ribosome production and protein synthesis, but apparently not by direct effects on the import of amino acids or glucose. The effect of insulin signaling upon TOR activity varies according to cellular type and context.

  19. Synthesis of peptides from amino acids and ATP with lysine-rich proteinoid

    Science.gov (United States)

    Nakashima, T.; Fox, S. W.

    1980-01-01

    The paper examines the synthesis of peptides from aminoacids and ATP with a lysine-rich protenoid. The latter in aqueous solution catalyzes the formation of peptides from free amino acids and ATP; this catalytic activity is not found in acidic protenoids, even though the latter contain a basic aminoacid. The pH optimum for the synthesis is about 11, but it is appreciable below 8 and above 13. Temperature data indicate an optimum at 20 C or above, with little increase in rate up to 60 C. Pyrophosphate can be used instead of ATP, but the yields are lower. The ATP-aided syntheses of peptides in aqueous solution occur with several types of proteinous aminoacids.

  20. Synthesis of Very-Long-Chain Fatty Acids in the Epidermis Controls Plant Organ Growth by Restricting Cell Proliferation

    OpenAIRE

    Nobusawa, Takashi; Okushima, Yoko; Nagata, Noriko; Kojima, Mikiko; Sakakibara, Hitoshi; UMEDA, MASAAKI

    2013-01-01

    The synthesis of very-long-chain fatty acids (VLCFAs) in the epidermis is essential for the proper control of cell growth in Arabidopsis. VLCFAs act via their ability to suppress cytokinin synthesis in the vasculature, thus preventing cell overproliferation in internal tissues.

  1. Caged O-phosphorothioyl amino acids as building blocks for Fmoc-based solid phase peptide synthesis

    OpenAIRE

    Aemissegger, Andreas; Carrigan, Christina N.; Imperiali, Barbara

    2007-01-01

    The synthesis of 1-(2-nitrophenylethyl) caged O-phosphorothioylserine, -threonine and tyrosine derivatives is reported. These amino acid building blocks can be directly incorporated into peptides by Fmoc-based solid phase synthesis as their pentafluorophenyl esters or as symmetric anhydrides. Upon irradiation with UV light, the thiophosphate group, representing a hydrolysis resistant phosphate analog, is revealed.

  2. Regioselectivity in the Ring Opening of Epoxides for the Synthesis of Aminocyclitols from D-(--Quinic Acid

    Directory of Open Access Journals (Sweden)

    Shu-Yu Yang

    2012-04-01

    Full Text Available Efficient syntheses of four aminocyclitols are reported. Each synthesis is accomplished in eight steps starting from D-(--quinic acid. The key step involves a highly regioselective ring opening of epoxides by sodium azide.

  3. Oleic acid coated magnetic nano-particles: Synthesis and characterizations

    International Nuclear Information System (INIS)

    Magnetic nano particles of Fe3O4 coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe2+ and Fe3+ ions. The nano particles were characterized using XRD, TEM, FTIR, TGA and VSM. X-ray diffraction studies showed that nano particles consist of single phase Fe3O4 having inverse spinel structure. The particle size obtained from width of Bragg peak is about 12.6 nm. TEM analysis showed that sizes of nano particles are in range of 6 to 17 nm with a dominant population at 12 - 14 nm. FTIR and TGA analysis showed that -COOH group of oleic acid is bound to the surface of Fe3O4 particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe3O4 particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm

  4. Synthesis and characterization of cashew gum/acrylic acid nanoparticles

    International Nuclear Information System (INIS)

    This paper describes the preparation of nanoparticles from cashew gum (CG) and acrylic acid (AA) by free radical polymerization using cerium (IV) ammonium nitrate (CAN) as an initiator. The yields of the nanoparticles (NP) obtained by varying the RCG/AA from 0.5 to 2.0 were between 65 and 40%. The FT-IR spectra of the NP samples showed bands characteristic of the cashew gum spectrum and a new band at 1560 cm-1 assigned to the stretching vibration of COO- groups of polyacrylic acid. On increasing the RCG/AA from 0.5 to 2.0 an increase in particle size was observed. The NP with an RCG/AA of 0.5 were smaller and had higher storage stability than the NP with an RCG/AA of 1.0 or 2.0. The increase in RCG/AA had no significant effect on the zeta potential of the NP in water. The NP were dried and re-dissolved in water to observe the effect of freeze-drying on particle size. For the NP with an RCG/AA of 0.5 an increase in particle size was observed from 71 to 402 nm, however, for the NP with an RCG/AA of 1.0 or 2.0 a small variation in particle diameter was noted. The behavior of the CG/AA NP was also found to be pH sensitive

  5. 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

  6. A concise route to dihydrobenzo[b]furans: formal total synthesis of (+)-lithospermic acid.

    Science.gov (United States)

    Fischer, Joshua; Savage, G Paul; Coster, Mark J

    2011-07-01

    A sequence of Sonogashira coupling, Pd(II)-catalyzed carbonylative annulation, and benzofuran reduction (Mg, MeOH, NH(4)Cl) provides a convergent and modular synthetic route to trans-2-aryl-2,3-dihydrobenzo[b]furan-3-carboxylates, which are a structural feature of numerous biologically active natural products. This versatile strategy was applied to the formal total synthesis of the anti-HIV natural product (+)-lithospermic acid. PMID:21648396

  7. Lewis acid free high speed synthesis of nimesulide-based novel N-substituted cyclic imides

    International Nuclear Information System (INIS)

    The first synthesis of nimesulide-based novel cyclic imides has been accomplished via the reaction of an amine prepared from nimesulide with appropriate anhydrides in the presence of sodium acetate. Using this process a variety of N-substituted cyclic imides was prepared in good yields in glacial acetic acid. Some of the compounds synthesized showed anti-inflammatory activities when tested in vivo. (author)

  8. Synthesis of DL-[2-13C,15N]aspartic acid

    International Nuclear Information System (INIS)

    A synthesis of the title compound from [13C]paraformaldehyde and [15N]ammonium chloride via ethyl 2-(1,3-[2-13C]dithianyl) acetate (3a) is described. Ethyl[3-13C]3-oxopropanoate derived in situ from 3a was converted by a stepwise Strecker procedure to DL-[2-13C,15N]aspartic acid (7a). (author)

  9. Lewis acid free high speed synthesis of nimesulide-based novel N-substituted cyclic imides

    Energy Technology Data Exchange (ETDEWEB)

    Kankanala, Kavitha; Mukkanti, Khagga [JNT University Hyderabad, Kukatpally (India); Pal, Sarbani, E-mail: sarbani277@yahoo.co [MNR Degree and PG College, Kukatpally, Hyderabad (India). Dept. of Chemistry; Reddy, Vangala Ranga [Dr. Reddy' s Laboratories Ltd. Integrated Product Development, Bachupally, Hyderabad (India)

    2010-07-01

    The first synthesis of nimesulide-based novel cyclic imides has been accomplished via the reaction of an amine prepared from nimesulide with appropriate anhydrides in the presence of sodium acetate. Using this process a variety of N-substituted cyclic imides was prepared in good yields in glacial acetic acid. Some of the compounds synthesized showed anti-inflammatory activities when tested in vivo. (author)

  10. The Bile Acid Synthesis Pathway Is Present and Functional in the Human Ovary

    OpenAIRE

    Nierstenhoefer, Maik; Tobiasch, Edda; Usheva, Anny; Smith, Laura; Yoo, Sang Wook; Penzias, Alan Stewart

    2009-01-01

    Background: Bile acids, end products of the pathway for cholesterol elimination, are required for dietary lipid and fat-soluble vitamin absorption and maintain the balance between cholesterol synthesis in the liver and cholesterol excretion. They are composed of a steroid structure and are primarily made in the liver by the oxidation of cholesterol. Cholesterol is also highly abundant in the human ovarian follicle, where it is used in the formation of the sex steroids. Methodology/Principal F...

  11. Synthesis of 2-(6-Acetamidobenzothiazolethio)acetic Acid Esters as Photosynthesis Inhibitors

    OpenAIRE

    Dusan Loos; Katarina Kralova; Eva Sidoova

    1998-01-01

    The synthesis and photosynthesis-inhibiting activity of 13 new 2-(6-acetamidobenzothiazolethio)acetic acid esters are reported. The new compounds were prepared by acetylation of 2-(alkoxycarbonylmethylthio)-6-aminobenzothiazoles with acetic anhydride. The structure of the compounds was verified by 1H NMR spectra. The compounds inhibit photosynthetic electron transfer in spinach chloroplasts. The structure - activity relation was studied. Lipophilicity was found to influence substantially phot...

  12. Synthesis of Fe Nanoparticles Functionalized with Oleic Acid Synthesized by Inert Gas Condensation

    OpenAIRE

    L. G. Silva; Solis-Pomar, F; C. D. Gutiérrez-Lazos; Manuel F. Meléndrez; Martinez, E.; A. Fundora; E. Pérez-Tijerina

    2014-01-01

    In this work, we study the synthesis of monodispersed Fe nanoparticles (Fe-NPs) in situ functionalized with oleic acid. The nanoparticles were self-assembled by inert gas condensation (IGC) technique by using magnetron-sputtering process. Structural characterization of Fe-NPs was performed by transmission electron microscopy (TEM). Particle size control was carried out through the following parameters: (i) condensation zone length, (ii) magnetron power, and (iii) gas flow (Ar and He). Typical...

  13. Synthesis and characterization of covalent diphenylalanine nanotube-folic acid conjugates

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Rindzevicius, Tomas; Wu, Kaiyu; Schmidt, Michael Stenbæk; Janik, Katarzyna Agnieszka; Boisen, Anja; Svendsen, Winnie Edith; Rozlosnik, Noemi; Castillo, Jaime

    2014-01-01

    Herein, we describe the synthesis and characterization of a covalent nanoscale assembly formed between diphenylalanine micro/nanotubes (PNT) and folic acid (FA). The conjugate was obtained via chemical functionalization through coupling of amine groups of PNTs and carboxylic groups of FA. The sur...... for applications in the detection and diagnosis of cancer or tropical diseases such as leishmaniasis and as a carrier nanosystem delivering drugs to malignant tumors that overexpress folate receptors....

  14. Early signal transduction linking the synthesis of jasmonic acid in plant

    OpenAIRE

    Hu, Xiangyang; Li, Wansha; Chen, Qi; YANG, YONGPING

    2009-01-01

    Jasmonate signaling plays a critical role in protecting plants from pathogens or insect attacks and in limiting damage from abiotic stress. Many events contribute to the regulation of jasmonic acid (JA) synthesis during abiotic or biotic stress, but the details of the underlying mechanism remain unclear. In this Mini-Review paper, we discuss the possible roles of reactive oxygen species (ROS), nitric oxide (NO), calcium influx and mitogen-activated protein kinase (MAPK) cascade during JA synt...

  15. Computer simulation aided synthesis of sodium acrylate/acrylic acid superabsorbent polymers

    OpenAIRE

    Gonçalves, Miguel; Pinto, Virgínia; Dias, Rolando; Costa, Mário Rui

    2011-01-01

    The influence of the synthesis conditions on the end use properties of SAPs was experimentally observed. Initial proportion crosslinker/acrylic acid and degree of neutralization are examples of parameters with strong influence in the performance of these materials. The kinetic model developed is able to capture the main features of SAP production. Ongoing research should allow the prediction of elastic properties of this class of materials.

  16. NOVEL 3-ACETYLCOUMARIN SCHIFFS BASE SYNTHESIS FROM DIFFERENT ACID HYDRAZIDE

    Directory of Open Access Journals (Sweden)

    Anees Pangal

    2013-10-01

    Full Text Available A new series of Schiffs bases, SB1, SB2 and SB3 were synthesized from 3-acetylcoumarin and different acid hydrazides. The 3-acetyl coumarin was synthesized starting from salicylaldehyde and ethylacetoacetate. The structures of the synthesized compounds have been established on the basis of physical and spectral data. They shows a prominent absorption of -(C=N- in FTIR. A survey of existing literature revealed that there are no reports describing the synthesis of such hydrazones.

  17. Synthesis of 2-(6-Acetamidobenzothiazolethioacetic Acid Esters as Photosynthesis Inhibitors

    Directory of Open Access Journals (Sweden)

    Dusan Loos

    1998-04-01

    Full Text Available The synthesis and photosynthesis-inhibiting activity of 13 new 2-(6-acetamidobenzothiazolethioacetic acid esters are reported. The new compounds were prepared by acetylation of 2-(alkoxycarbonylmethylthio-6-aminobenzothiazoles with acetic anhydride. The structure of the compounds was verified by 1H NMR spectra. The compounds inhibit photosynthetic electron transfer in spinach chloroplasts. The structure - activity relation was studied. Lipophilicity was found to influence substantially photosynthetic electron transfer.

  18. Synthesis of methylphosphonic acid by marine microbes: a source for methane in the aerobic ocean

    OpenAIRE

    Metcalf, William W.; Griffin, Benjamin M.; Cicchillo, Robert M.; Gao, Jiangtao; Janga, Sarath Chandra; Cooke, Heather A.; Circello, Benjamin T.; Evans, Bradley S; Martens-Habbena, Willm; Stahl, David A.; van der Donk, Wilfred A

    2012-01-01

    Relative to the atmosphere, much of the aerobic ocean is supersaturated with methane; however, the source of this important greenhouse gas remains enigmatic. Catabolism of methylphosphonic acid by phosphorus-starved marine microbes, with concomitant release of methane, has been suggested to explain this phenomenon, yet methylphosphonate is not a known natural product, nor has it been detected in natural systems. Further, its synthesis from known natural products would require unknown biochemi...

  19. Synthesis of 5-,6-, and 7-membered heterocycles from barbituric acid derivatives

    OpenAIRE

    Guyader, David

    2011-01-01

    SUMMARY A new procedure has been developed for the synthesis of barbituric acid derivatives. The reactions were performed under solvent free conditions without any catalyst. Employing this synthetic route, a large number of chalconoids and 5-,6-, and 7-membered heterocycles have been successfully synthesized in a very short time. The chalconoids have been synthesized from a barbituric derivative and substituted benzaldehydes. The effect of different substituents on the yield of the re...

  20. Synthesis and characterization of organic-inorganic hybrids formed between conducting polymers and crystalline antimonic acid

    OpenAIRE

    Beleze Fábio A.; Zarbin Aldo J. G.

    2001-01-01

    In this paper we report the synthesis and characterization of novel organic-inorganic hybrid materials between the crystalline antimonic acid (CAA) and two conductive polymers: polypyrrole and polyaniline. The hybrids were obtained by in situ oxidative polymerization of monomers by the Sb(V) present in the pyrochlore-like CAA structure. The materials were characterized by infrared and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, CHN elemental analysis and electronic paramagnetic...

  1. Influence of peroxometallic intermediaries present on polyoxometalates nanoparticles surface on the adipic acid synthesis

    OpenAIRE

    Alcañiz Monge, Juan; Trautwein, Guido; García García, Avelina

    2014-01-01

    The cyclohexene oxidation by hydrogen peroxide catalysed by polyoxometalates (POM) has been shown as an adequate green route for the adipic acid synthesis. In this study, it has been demonstrated that POM's salts are effective catalysts for this reaction and how peroxopolyoxometalates intermediaries are the truly responsible species of the POM's salts catalytic activity and solubility. However, the latter can be reduced by calcining the catalyst previously. Polyoxomolybdates salts generally p...

  2. Exercise, Amino Acids and Aging in the Control of Human Muscle Protein Synthesis

    OpenAIRE

    Walker, Dillon K; Dickinson, Jared M.; Timmerman, Kyle L; Drummond, Micah J.; Reidy, Paul T.; Fry, Christopher S.; Gundermann, David M; Rasmussen, Blake B

    2011-01-01

    In this review we discuss recent research in the field of human skeletal muscle protein metabolism characterizing the acute regulation of mammalian target of rapamycin complex (mTORC) 1 signaling and muscle protein synthesis (MPS) by exercise, amino acid nutrition and aging. Resistance exercise performed in the fasted state stimulates mixed MPS within 1 h post-exercise, which can remain elevated for 48 h. We demonstrate that the activation of mTORC1 signaling (and subsequently enhanced transl...

  3. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  4. Synthesis and biological activity of hydroxylated derivatives of linoleic acid and conjugated linoleic acids.

    Science.gov (United States)

    Li, Zhen; Tran, Van H; Duke, Rujee K; Ng, Michelle C H; Yang, Depo; Duke, Colin C

    2009-03-01

    Allylic hydroxylated derivatives of the C18 unsaturated fatty acids were prepared from linoleic acid (LA) and conjugated linoleic acids (CLAs). The reaction of LA methyl ester with selenium dioxide (SeO(2)) gave mono-hydroxylated derivatives, 13-hydroxy-9Z,11E-octadecadienoic acid, 13-hydroxy-9E,11E-octadecadienoic acid, 9-hydroxy-10E,12Z-octadecadienoic acid and 9-hydroxy-10E,12E-octadecadienoic acid methyl esters. In contrast, the reaction of CLA methyl ester with SeO(2) gave di-hydroxylated derivatives as novel products including, erythro-12,13-dihydroxy-10E-octadecenoic acid, erythro-11,12-dihydroxy-9E-octadecenoic acid, erythro-10,11-dihydroxy-12E-octadecenoic acid and erythro-9,10-dihydroxy-11E-octadecenoic acid methyl esters. These products were purified by normal-phase short column vacuum chromatography followed by high-performance liquid chromatography (HPLC). Their chemical structures were characterized by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR). The allylic hydroxylated derivatives of LA and CLA exhibited moderate in vitro cytotoxicity against a panel of human cancer cell lines including chronic myelogenous leukemia K562, myeloma RPMI8226, hepatocellular carcinoma HepG2 and breast adenocarcinoma MCF-7 cells (IC(50) 10-75 microM). The allylic hydroxylated derivatives of LA and CLA also showed toxicity to brine shrimp with LD(50) values in the range of 2.30-13.8 microM. However these compounds showed insignificant toxicity to honeybee at doses up to 100 microg/bee. PMID:19146841

  5. Integrated process of distillation with side reactors for synthesis of organic acid esters

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Chandrakant B; Prindle, John C; Kolah, Aspri; Miller, Dennis J; Lira, Carl T

    2015-11-04

    An integrated process and system for synthesis of organic-acid esters is provided. The method of synthesizing combines reaction and distillation where an organic acid and alcohol composition are passed through a distillation chamber having a plurality of zones. Side reactors are used for drawing off portions of the composition and then recycling them to the distillation column for further purification. Water is removed from a pre-reactor prior to insertion into the distillation column. An integrated heat integration system is contained within the distillation column for further purification and optimizing efficiency in the obtaining of the final product.

  6. Polyol-Free Synthesis of Uniformly Dispersed Pt/Graphene Oxide Electrocatalyst by Sulfuric Acid Treatment

    OpenAIRE

    Tae Kyu Lee; Hyang Jin Park; Min Ki Kwon; Ju Hae Jung; Junbom Kim; Seung Hyun Hur

    2012-01-01

    Polyol-free synthesis of highly loaded Pt catalysts on sulfuric-acid-treated graphene oxide (SGO) was reported. Sulfuric acid treatment increased the surface hydroxyl groups on graphene oxide (GO), which contributed to the reduction of Pt precursors in the absence of external reducing agent. By adjusting pH during the Pt reduction, we can get uniformly dispersed 2.5 nm size Pt nanoparticles on GO surface even at 50 wt% Pt loading amount. Cyclic voltammetry showed that increased pH resulted in...

  7. ENANTIOPURE R(-)-3-AMINOISOBUTYRIC ACID SYNTHESIS USING Pseudomonas aeruginosa AS ENANTIOSPECIFIC BIOCATALYST

    Scientific Electronic Library Online (English)

    M. V. C. B., Cortes; R. R., Menezes; E.G., Oestreicher.

    2015-03-01

    Full Text Available Abstract The main goal of this research was the synthesis of enantiopure R(-)-3-aminoisobutyric acid from dihydrothymine with good yield, high stereospecificity and relative simplicity. Seventy two percent yield of the product was obtained in three steps. Step one consisted of dihydrothymine racemiz [...] ation. Step two was a dihydropyrimidinase reaction involving the Pseudomonas aeruginosa 10145 bacterial strain as the biocatalyst. Step three was performed with a diazotization reaction. The bacteria's enzymes determined the stereochemistry of the process since the diazotization reaction did not interfere at this point. The results of this work provide an interesting method for the production of commercial ?-amino acids from other substituteddihydrothymines.

  8. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    Directory of Open Access Journals (Sweden)

    Patrick Rabe

    2014-08-01

    Full Text Available Tropodithietic acid (TDA is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus aureus and Vibrio anguillarum for a structure–activity relationship (SAR study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues is presented and the bioactivity of the synthetic compounds is discussed.

  9. Aqueous citric acid as green reaction media for the synthesis of octahydroxanthenes

    Directory of Open Access Journals (Sweden)

    Camilo A. Navarro D.

    2013-08-01

    Full Text Available A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

  10. Chemo-enzymatic synthesis of the carbohydrate antigen N-glycolylneuraminic acid from glucose

    OpenAIRE

    Pearce, Oliver M. T.; Varki, Ajit

    2010-01-01

    N-Glycolylneuraminic acid (Neu5Gc) is a non-human sialic acid, which may play a significant role in human pathologies, such as cancer, and vascular disease. Further studies into the role of Neu5Gc in human disease is hindered by limited sources of this carbohydrate. Using a chemoenzymatic approach, Neu5Gc was accessed in 6 steps from glucose. The synthesis allows access to gram scale quantities quickly and economically, and produces Neu5Gc in superior quality to commercial sources. Finally, w...

  11. Concise and Straightforward Asymmetric Synthesis of a Cyclic Natural Hydroxy-Amino Acid

    Directory of Open Access Journals (Sweden)

    Mario J. Simirgiotis

    2014-11-01

    Full Text Available An enantioselective total synthesis of the natural amino acid (2S,4R,5R-4,5-di-hydroxy-pipecolic acid starting from D-glucoheptono-1, 4-lactone is presented. The best sequence employed as a key step the intramolecular nucleophilic displacement by an amino function of a 6-O-p-toluene-sulphonyl derivative of a methyl D-arabino-hexonate and involved only 12 steps with an overall yield of 19%. The structures of the compounds synthesized were elucidated on the basis of comprehensive spectroscopic (NMR and MS and computational analysis.

  12. ENANTIOPURE R(--3-AMINOISOBUTYRIC ACID SYNTHESIS USING Pseudomonas aeruginosa AS ENANTIOSPECIFIC BIOCATALYST

    Directory of Open Access Journals (Sweden)

    M. V. C. B. Cortes

    2015-03-01

    Full Text Available Abstract The main goal of this research was the synthesis of enantiopure R(--3-aminoisobutyric acid from dihydrothymine with good yield, high stereospecificity and relative simplicity. Seventy two percent yield of the product was obtained in three steps. Step one consisted of dihydrothymine racemization. Step two was a dihydropyrimidinase reaction involving the Pseudomonas aeruginosa 10145 bacterial strain as the biocatalyst. Step three was performed with a diazotization reaction. The bacteria's enzymes determined the stereochemistry of the process since the diazotization reaction did not interfere at this point. The results of this work provide an interesting method for the production of commercial ?-amino acids from other substituteddihydrothymines.

  13. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    DEFF Research Database (Denmark)

    Rabe, Patrick; Klapschinski, Tim A.; Brock, Nelson L.; Citron, Christian A.; D'Alvise, Paul; Gram, Lone; Dickschat, Jeroen S.

    2014-01-01

    Tropodithietic acid (TDA) is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus...... aureus and Vibrio anguillarum for a structure-activity relationship (SAR) study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues...

  14. Human fatty acid synthesis is stimulated by a eucaloric low fat, high carbohydrate diet.

    OpenAIRE

    Hudgins, L C; Hellerstein, M; Seidman, C; Neese, R; Diakun, J; Hirsch, J.

    1996-01-01

    A new experimental approach was used to determine whether a eucaloric, low fat, high carbohydrate diet increases fatty acid synthesis. Normally volunteers consumed low fat liquid formula diets (10% of calories as fat and 75% as glucose polymers, n = 7) or high fat diets (40% of calories as fat and 45% as glucose polymers, n = 3) for 25 d. The fatty acid composition of each diet was matched to the composition of each subject's adipose tissue and compared with the composition of VLDL triglyceri...

  15. Synthesis and NMR elucidation of novel octa-amino acid resorcin[4]arenes derivatives

    Scientific Electronic Library Online (English)

    Iman, Elidrisi; Pralav V., Bhatt; Thavendran, Govender; Hendrik G., Kruger; Glenn E. M., Maguire.

    Full Text Available The synthesis of nine novel protected amino acid cavitands is reported. All have four pendant M-undecyl chains and 'headgroups' connected by a two-carbon spacer at eight positions on the aromatic rings. The amino acids employed are glycine, alanine, phenylalanine, leucine, proline, tryptophan, serin [...] e, glutamine and lysine. The structures of the compounds were elucidated using one and two-dimensional NMR techniques which verified that all octa-substituted cavitands have symmetrical C2v conformation at room temperature. These compounds have potential synthetic ion channel applications.

  16. 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......-cyclopent-3-enecarboxylic acids. Their structure was established using a combination of 1H NMR spectroscopy and molecular mechanics calculations carried out on the intermediate cycloadducts (+/-)-11 and (+/-)-12. Amino acid derivatives (+/-)-7 and (+/-)-8 were assayed at ionotropic and metabotropic glutamic...... acid receptor subtypes and their activity compared with that of trans-ACPD and cis-ACPD. The results show that the replacement of the omega-carboxylic group of the model compounds with the 3-hydroxy-delta2-isoxazoline moiety abolishes or reduces drastically the activity at the metabotropic glutamate...

  17. Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

    Science.gov (United States)

    Attallah, Olivia A.; Girgis, E.; Abdel-Mottaleb, Mohamed M. S. A.

    2016-02-01

    Non-aggregated magnetite nanorods with average diameters of 20-30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications.

  18. The effect of pantothenic acid deficiency on keratinocyte proliferation and the synthesis of keratinocyte growth factor and collagen in fibroblasts.

    Science.gov (United States)

    Kobayashi, Daisaku; Kusama, Miho; Onda, Masaaki; Nakahata, Norimichi

    2011-01-01

    It has been reported that pantothenic acid (vitamin B5) and panthenol, an alcohol derivative of pantothenic acid, have beneficial moisturizing effects on the skin. However, few studies have investigated the mechanism of action of pantothenic acid on skin tissues. We tried to clarify the role of pantothenic acid on skin function by using keratinocytes and fibroblasts. The depletion of pantothenic acid from the culture medium suppressed keratinocyte proliferation and promoted differentiation. Moreover, pantothenic acid depletion decreased the synthesis of keratinocyte growth factor and procollagen 4a2 in fibroblasts. These results suggest that pantothenic acid is essential for maintaining keratinocyte proliferation and differentiation. PMID:21258175

  19. Metabolic switch during adipogenesis: From branched chain amino acid catabolism to lipid synthesis.

    Science.gov (United States)

    Halama, Anna; Horsch, Marion; Kastenmüller, Gabriele; Möller, Gabriele; Kumar, Pankaj; Prehn, Cornelia; Laumen, Helmut; Hauner, Hans; Hrabĕ de Angelis, Martin; Beckers, Johannes; Suhre, Karsten; Adamski, Jerzy

    2016-01-01

    Fat cell metabolism has an impact on body homeostasis and its proper function. Nevertheless, the knowledge about simultaneous metabolic processes, which occur during adipogenesis and in mature adipocytes, is limited. Identification of key metabolic events associated with fat cell metabolism could be beneficial in the field of novel drug development, drug repurposing, as well as for the discovery of patterns predicting obesity risk. The main objective of our work was to provide comprehensive characterization of metabolic processes occurring during adipogenesis and in mature adipocytes. In order to globally determine crucial metabolic pathways involved in fat cell metabolism, metabolomics and transcriptomics approaches were applied. We observed significantly regulated metabolites correlating with significantly regulated genes at different stages of adipogenesis. We identified the synthesis of phosphatidylcholines, the metabolism of even and odd chain fatty acids, as well as the catabolism of branched chain amino acids (BCAA; leucine, isoleucine and valine) as key regulated pathways. Our further analysis led to identification of an enzymatic switch comprising the enzymes Hmgcs2 (3-hydroxy-3-methylglutaryl-CoA synthase) and Auh (AU RNA binding protein/enoyl-CoA hydratase) which connects leucine degradation with cholesterol synthesis. In addition, propionyl-CoA, a product of isoleucine degradation, was identified as a putative substrate for odd chain fatty acid synthesis. The uncovered crosstalks between BCAA and lipid metabolism during adipogenesis might contribute to the understanding of molecular mechanisms of obesity and have potential implications in obesity prediction. PMID:26408941

  20. Oxidative cleavage of erucic acid for the synthesis of brassylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed J. Nasrullah; Pooja Thapliyal; Erica N. Pfarr; Nicholas S. Dusek; Kristofer L. Schiele; James A. Bahr

    2010-10-29

    The main focus of this work is to synthesize Brassylic Acid (BA) using oxidative cleavage of Erucic Acid (EA). Crambe (Crambe abyssinica) is an industrial oilseed grown in North Dakota. Crambe has potential as an industrial fatty acid feedstock as a source of Erucic acid (EA). It has approximately 50-60 % of EA, a C{sub 22} monounsaturated fatty acid. Oxidative cleavage of unsaturated fatty acids derived from oilseeds produces long chain (9, 11, and 13 carbon atoms) dibasic and monobasic acids. These acids are known commercial feedstocks for the preparation of nylons, polyesters, waxes, surfactants, and perfumes. Other sources of EA are Rapeseed seed oil which 50-60 % of EA. Rapeseed is grown outside USA. The oxidative cleavage of EA was done using a high throughput parallel pressure reactor system. Kinetics of the reaction shows that BA yields reach a saturation at 12 hours. H{sub 2}WO{sub 4} was found to be the best catalyst for the oxidative cleavage of EA. High yields of BA were obtained at 80 C with bubbling of O{sub 2} or 10 bar of O{sub 2} for 12 hours.

  1. Differential modulation of citrate synthesis and release by fatty acids in perfused working rat hearts.

    Science.gov (United States)

    Vincent, Genevieve; Bouchard, Bertrand; Khairallah, Maya; Des Rosiers, Christine

    2004-01-01

    The objective of this study was to test the effect of increasing fatty acid concentrations on substrate fluxes through pathways leading to citrate synthesis and release in the heart. This was accomplished using semirecirculating work-performing rat hearts perfused with substrate mixtures mimicking the in situ milieu (5.5 mM glucose, 8 nM insulin, 1 mM lactate, 0.2 mM pyruvate, and 0.4 mM oleate-albumin) and 13C methods. Raising the fatty acid concentration from 0.4 to 1 mM with long-chain oleate or medium-chain octanoate resulted in a lowering ( approximately 20%) of cardiac output and efficiency with unaltered O2 consumption. At the metabolic level, beyond the expected effects of high fatty acid levels on the contribution of pyruvate decarboxylation (reduced >3-fold) and beta-oxidation (enhanced approximately 3-fold) to citrate synthesis, there was also a 2.4-fold lowering of anaplerotic pyruvate carboxylation. Despite the dual inhibitory effect of high fatty acids on pyruvate decarboxylation and carboxylation, tissue citrate levels were twofold higher, but citrate release rates remained unchanged at 11-14 nmol/min, representing <0.5% of citric acid cycle flux. A similar trend was observed for most metabolic parameters after oleate or octanoate addition. Together, these results emphasize a differential modulation of anaplerotic pyruvate carboxylation and citrate release in the heart by fatty acids. We interpret the lack of effects of high fatty acid concentrations on citrate release rates as suggesting that, under physiological conditions, this process is maximal, probably limited by the activity of its mitochondrial or plasma membrane transporter. Limited citrate release at high fatty acid concentrations may have important consequences for the heart's fuel metabolism and function. PMID:12933348

  2. Radiation synthesis of nanosilver nanohydrogels of poly(methacrylic acid)

    Science.gov (United States)

    Gupta, Bhuvanesh; Gautam, Deepti; Anjum, Sadiya; Saxena, Shalini; Kapil, Arti

    2013-11-01

    Nanosilver nanohydrogels (nSnH) of poly(methacrylic acid) were synthesized and stabilized using gamma irradiation. The main objective of this study was to develop silver nanoparticles and to evaluate the antimicrobial activity. Radiation helps in the polymerization, crosslinking and reduction of silver nitrate as well. Highly stable and uniformly distributed silver nanoparticles have been obtained within hydrogel network by water in oil nanoemulsion polymerization and were evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) respectively. TEM showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network. The mean size of silver nanoparticles ranging is 10-50 nm. The nanohydrogels showed good swelling in water. Antibacterial studies of nSnH suggest that it can be a good candidate as coating material in biomedical applications.

  3. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B; Bräuner-Osborne, Hans; Lützhøft, H H; Poulsen, M V; Eriksen, L; Krogsgaard-Larsen, P

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2), on...

  4. Expanding the amino acid repertoire of ribosomal polypeptide synthesis via the artificial division of codon boxes

    Science.gov (United States)

    Iwane, Yoshihiko; Hitomi, Azusa; Murakami, Hiroshi; Katoh, Takayuki; Goto, Yuki; Suga, Hiroaki

    2016-04-01

    In ribosomal polypeptide synthesis the library of amino acid building blocks is limited by the manner in which codons are used. Of the proteinogenic amino acids, 18 are coded for by multiple codons and therefore many of the 61 sense codons can be considered redundant. Here we report a method to reduce the redundancy of codons by artificially dividing codon boxes to create vacant codons that can then be reassigned to non-proteinogenic amino acids and thereby expand the library of genetically encoded amino acids. To achieve this, we reconstituted a cell-free translation system with 32 in vitro transcripts of transfer RNASNN (tRNASNN) (S = G or C), assigning the initiator and 20 elongator amino acids. Reassignment of three redundant codons was achieved by replacing redundant tRNASNNs with tRNASNNs pre-charged with non-proteinogenic amino acids. As a demonstration, we expressed a 32-mer linear peptide that consists of 20 proteinogenic and three non-proteinogenic amino acids, and a 14-mer macrocyclic peptide that contains more than four non-proteinogenic amino acids.

  5. Expanding the amino acid repertoire of ribosomal polypeptide synthesis via the artificial division of codon boxes.

    Science.gov (United States)

    Iwane, Yoshihiko; Hitomi, Azusa; Murakami, Hiroshi; Katoh, Takayuki; Goto, Yuki; Suga, Hiroaki

    2016-04-01

    In ribosomal polypeptide synthesis the library of amino acid building blocks is limited by the manner in which codons are used. Of the proteinogenic amino acids, 18 are coded for by multiple codons and therefore many of the 61 sense codons can be considered redundant. Here we report a method to reduce the redundancy of codons by artificially dividing codon boxes to create vacant codons that can then be reassigned to non-proteinogenic amino acids and thereby expand the library of genetically encoded amino acids. To achieve this, we reconstituted a cell-free translation system with 32 in vitro transcripts of transfer RNASNN (tRNASNN) (S = G or C), assigning the initiator and 20 elongator amino acids. Reassignment of three redundant codons was achieved by replacing redundant tRNASNNs with tRNASNNs pre-charged with non-proteinogenic amino acids. As a demonstration, we expressed a 32-mer linear peptide that consists of 20 proteinogenic and three non-proteinogenic amino acids, and a 14-mer macrocyclic peptide that contains more than four non-proteinogenic amino acids. PMID:27001726

  6. Synthesis and structural characterization of a new open-framework zinc terephthalate Zn 3(OH) 2(bdc) 2·2DEF, with infinite Zn-( μ3-OH)-Zn chains

    Science.gov (United States)

    Loiseau, Thierry; Muguerra, Hervé; Férey, Gérard; Haouas, Mohamed; Taulelle, Francis

    2005-03-01

    A new zinc carboxylate Zn 3(OH) 2(bdc) 2·2DEF was synthesized under mild hydrothermal conditions (100 °C, 40 h) in the presence of 1,4-benzenedicarboxylic (bdc) acid, in N,N'-diethylformamide (DEF) solvent. Its structure, characterized by means of single-crystal XRD analysis, consists of connection of ZnO 2(OH) 2 tetrahedra corner-sharing with ZnO 4(OH) 2 octahedra. Two adjacent ZnO 2(OH) 2 tetrahedra have a common edge corresponding to hydroxy group, which is also linked to the octahedrally coordinated zinc atoms with a μ3 configuration. This resulting connection mode generates infinite chains running along the c-axis, and connected to each other via the bdc ligand. Three-dimensional framework is therefore formed with channels running along the c-axis, parallel to the infinite Zn-OH-Zn chains. Within the tunnels are trapped the DEF species, which interacts via hydrogen-bond to the μ3-hydroxy of the zinc chains with the terminal oxygen atom of the formamide function. Analysis by solid state NMR ( 1H and 13C) has confirmed both the presence of occluded solvent molecules within the pores and the incorporation of carboxylate moieties into the framework. The structure of Zn 3(OH) 2(bdc) 2·2DEF is closely related to those of MOF-69 series, constructed with longer organic linkers (4,4'-biphenyldicarboxylate and 2,6-naphthalenedicarboxylate). The structure is observed to loose crystallinity upon heating and removal of the occluded DEF moieties. Crystal data for [Zn 9(OH) 6(O 2C-C 6H 4-CO 2) 6]·6[(CH 3-CH 2) 2NCHO]: a=17.7374(3) Å, b=15.2605(2) Å, c=18.2635(2) Å, β=113.071(1)°, V=4548.2(1) Å3, P21/n (no. 14), Z=1, R1=0.0510, wR2=0.1302 for 11877 reflections I>2σ(I).

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

    Science.gov (United States)

    Falaise, Clment; Charles, Jean-Sbastien; 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)66DMF12H2O (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

  8. Fatty acid synthesis is essential in embryonic development: Fatty acid synthase null mutants and most of the heterozygotes die in utero

    OpenAIRE

    Chirala, Subrahmanyam S.; Chang, Hua; Matzuk, Martin; Abu-Elheiga, Lutfi; Mao, Jianqiang; Mahon, Kathleen; Finegold, Milton; Wakil, Salih J.

    2003-01-01

    In animals, including humans, the source of long-chain saturated fatty acids is de novo synthesis, which is mediated by fatty acid synthase (FAS), ingested food, or both. To understand the importance of de novo fatty acid synthesis, we generated FAS knockout mice. The heterozygous FAS mutants (Fasn+/) are ostensibly normal. In Fasn+/ mice the levels of FAS mRNA and the FAS activity are ?50% and 35% lower, respectively, than those of WT mice; hence, FAS levels are affected by gene dos...

  9. The first proton sponge-based amino acids: synthesis, acid-base properties and some reactivity.

    Science.gov (United States)

    Ozeryanskii, Valery A; Gorbacheva, Anastasia Yu; Pozharskii, Alexander F; Vlasenko, Marina P; Tereznikov, Alexander Yu; Chernov'yants, Margarita S

    2015-08-21

    The first hybrid base constructed from 1,8-bis(dimethylamino)naphthalene (proton sponge or DMAN) and glycine, N-methyl-N-(8-dimethylamino-1-naphthyl)aminoacetic acid, was synthesised in high yield and its hydrobromide was structurally characterised and used to determine the acid-base properties via potentiometric titration. It was found that the basic strength of the DMAN-glycine base (pKa = 11.57, H2O) is on the level of amidine amino acids like arginine and creatine and its structure, zwitterionic vs. neutral, based on the spectroscopic (IR, NMR, mass) and theoretical (DFT) approaches has a strong preference to the zwitterionic form. Unlike glycine, the DMAN-glycine zwitterion is N-chiral and is hydrolytically cleaved with the loss of glycolic acid on heating in DMSO. This reaction together with the mild decarboxylative conversion of proton sponge-based amino acids into 2,3-dihydroperimidinium salts under air-oxygen was monitored with the help of the DMAN-alanine amino acid. The newly devised amino acids are unique as they combine fluorescence, strongly basic and redox-active properties. PMID:26159785

  10. Design, Synthesis, and Antimycobacterial Activity of Novel Theophylline-7-Acetic Acid Derivatives With Amino Acid Moieties.

    Science.gov (United States)

    Stavrakov, Georgi; Valcheva, Violeta; Voynikov, Yulian; Philipova, Irena; Atanasova, Mariyana; Konstantinov, Spiro; Peikov, Plamen; Doytchinova, Irini

    2016-03-01

    The theophylline-7-acetic acid (7-TAA) scaffold is a promising novel lead compound for antimycobacterial activity. Here, we derive a model for antitubercular activity prediction based on 14 7-TAA derivatives with amino acid moieties and their methyl esters. The model is applied to a combinatorial library, consisting of 40 amino acid and methyl ester derivatives of 7-TAA. The best three predicted compounds are synthesized and tested against Mycobacterium tuberculosis H37Rv. All of them are stable, non-toxic against human cells and show antimycobacterial activity in the nanomolar range being 60 times more active than ethambutol. PMID:26502828

  11. Radiation synthesis of nanosilver nanohydrogels of poly(methacrylic acid)

    International Nuclear Information System (INIS)

    Nanosilver nanohydrogels (nSnH) of poly(methacrylic acid) were synthesized and stabilized using gamma irradiation. The main objective of this study was to develop silver nanoparticles and to evaluate the antimicrobial activity. Radiation helps in the polymerization, crosslinking and reduction of silver nitrate as well. Highly stable and uniformly distributed silver nanoparticles have been obtained within hydrogel network by water in oil nanoemulsion polymerization and were evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) respectively. TEM showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network. The mean size of silver nanoparticles ranging is 10–50 nm. The nanohydrogels showed good swelling in water. Antibacterial studies of nSnH suggest that it can be a good candidate as coating material in biomedical applications. - Highlights: • Nanosilver nanohydrogels of PMAA were synthesized and stabilized using Υ-irradiation. • The mean size of silver nanoparticles ranging is 10–50 nm. • Antibacterial studies of nSnH suggest it to be a good candidate for biomedical applications

  12. Slightly viscous amino acid ionic liquids: synthesis, properties, and calculations.

    Science.gov (United States)

    He, Ling; Tao, Guo-Hong; Parrish, Damon A; Shreeve, Jean'ne M

    2009-11-19

    Slightly viscous N-alkyl-substituted glycine ester ionic liquids were prepared via alkylation of glycine ethyl esters with appropriate haloalkanes followed by anion exchange with lithium bis(trifluoromethanesulfonyl)amide. These ionic liquids have been characterized by IR, NMR, elemental analysis, thermal stability, phase behavior, viscosity, and density. Compound 9 crystallizes in the monoclinic system, P2(1)/c. The viscosities of the N,N,N-trialkyl-substituted glycine ester ionic liquids (6, 8, 10) are in the approximately 200 to 400 cP range at 25 degrees C. While exhibiting liquid characteristics analogous to the traditional heterocyclic ionic liquids, these new liquids are much less viscous than known amino acid ionic liquids. The correlation of viscosity and temperature was determined. To understand the influence of the alkyl and ester-substituted groups on viscosity, the electronic distributions and the electrostatic potential surfaces of the glycine-based cations, including glycine (Gly(+)), glycine ethyl ester (GlyET(+)), N,N-dimethyl glycine (DMGly(+)), N,N-dimethyl glycine ethyl ester (DMGlyET(+)), N,N-dimethyl-N-propyl glycine ethyl ester (DMPGlyET(+)), N,N-dimethyl-N-3-fluoropropyl glycine ethyl ester (DMPFGlyET(+)), and N-butyl-N,N-dimethyl glycine ethyl ester (DMBGlyET(+)) cations have been investigated and analyzed. The possible effects on the viscosity coming from the intermolecular interactions arising from Coulomb interactions, hydrogen bonding, polarizability effects, and van der Waals interactions are considered. PMID:19856931

  13. Synthesis of unusual alpha-amino acids and study of the effect of their incorporation into antimicrobial peptides. Total synthesis of biactive marine natural products and analogues thereof

    OpenAIRE

    El Marrouni El Ghazaoui, Abdellatif

    2012-01-01

    The principle theme of this thesis was the synthesis of bioactive compounds. To this end, this work was focus on two main projects. The first one, which was carried out in the Department of Chemistry of the University of Girona under the supervision of Dr Montserrat Heras, concerned the synthesis of new unnatural amino acids bearing a pyrimidine ring within their side chain for incorporation into the antimicrobial peptide BP100 following a rational design in order to improve its biological pr...

  14. Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media.

    Science.gov (United States)

    Moret, Séverine; Dyson, Paul J; Laurenczy, Gábor

    2014-01-01

    The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40 °C, 0.2 M formic acid can be obtained under 200 bar, however, in DMSO the same catalyst affords 1.9 M formic acid. In both solvents the catalysts can be reused multiple times without a decrease in activity. Worldwide demand for formic acid continues to grow, especially in the context of a renewable energy hydrogen carrier, and its production from CO2 without base, via the direct catalytic carbon dioxide hydrogenation, is considerably more sustainable than the existing routes. PMID:24886955

  15. Synthesis of 2-(bromomethyl-13C)-fumaric acid (bromomesaconic acid)

    International Nuclear Information System (INIS)

    The fumarase inhibitor, bromomescaconic acid, has been synthesized with 13C labeling in the bromomethyl group. Di-t-butyl acetylenedicarboxylate was converted with Li (13CH3)2Cu to di-t-butyl (methyl-13C)citraconate. Photochemical isomerization of this di-t-butyl (methyl-13C)mesaconate, followed by deblocking with trifluoroacetic acid gave the title compound. (author)

  16. Metal-Free, Acid-Catalyzed ortho-Directed Synthesis of Anthranilic Acid Derivatives Using Carbodiimides.

    Science.gov (United States)

    Culf, Adrian S; Čuperlović-Culf, Miroslava; Ouellette, Rodney J; Decken, Andreas

    2015-06-01

    One-pot syntheses of fluorescent o-aminobenzoates, o-aminopyridine carboxylates, and a 2'-amino-[1,1'-biphenyl]-2-carboxylic acid are described. Carbodiimides are used as the source of the 2-amino function which inserts onto an aromatic ring using S(N)Ar reaction conditions. This method proceeds regiospecifically with a range of 2-fluoroaromatic acids or esters bearing further aryl fluorine, trifluoromethyl, and cyano substituents. PMID:25990766

  17. Sulfanilic acid functionalized mesoporous SBA-15: A water-tolerant solid acid catalyst for the synthesis of uracil fused spirooxindoles as antioxidant agents

    Indian Academy of Sciences (India)

    Robabeh Baharfar; Razieh Azimi

    2015-08-01

    Incorporating sulfanilic acid as a hydrophobic Brønsted acid inside the nanospaces of SBA-15 led to a water-tolerant solid acid catalyst, SBA-15-PhSO 3 H, which showed excellent catalytic performance in synthesis of uracil-fused spirooxindoles in aqueous ethanol. The synthesized compounds were evaluated for their antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay.

  18. Synthesis and anticancer activity of novel fluorinated asiatic acid derivatives.

    Science.gov (United States)

    Gonçalves, Bruno M F; Salvador, Jorge A R; Marín, Silvia; Cascante, Marta

    2016-05-23

    A series of novel fluorinated Asiatic Acid (AA) derivatives were successfully synthesized, tested for their antiproliferative activity against HeLa and HT-29 cell lines, and their structure activity relationships were evaluated. The great majority of fluorinated derivatives showed stronger antiproliferative activity than AA in a concentration dependent manner. The most active compounds have a pentameric A-ring containing an α,β-unsaturated carbonyl group. The compounds with better cytotoxic activity were then evaluated against MCF-7, Jurkat, PC-3, A375, MIA PaCa-2 and BJ cell lines. Derivative 14 proved to be the most active compound among all tested derivatives and its mechanism of action was further investigated in HeLa cell line. The results showed that compound 14 induced cell cycle arrest in G0/G1 stage as a consequence of up-regulation of p21(cip1/waf1) and p27(kip1) and down-regulation of cyclin D3 and Cyclin E. Furthermore, compound 14 was found to induce caspase driven-apoptosis with activation of caspases-8 and caspase-3 and the cleavage of PARP. The cleavage of Bid into t-Bid, the up-regulation of Bax and the down-regulation of Bcl-2 were also observed after treatment of HeLa cells with compound 14. Taken together, these mechanistic studies revealed the involvement of extrinsic and intrinsic pathways in the apoptotic process induced by compound 14. Importantly, the antiproliferative activity of this compound on the non-tumor BJ human fibroblast cell line is weaker than in the tested cancer cell lines. The enhanced potency (between 45 and 90-fold more active than AA in a panel of cancer cell lines) and selectivity of this new AA derivative warrant further preclinical evaluation. PMID:26974379

  19. Thyroid hormone activation of retinoic acid synthesis in hypothalamic tanycytes.

    Science.gov (United States)

    Stoney, Patrick N; Helfer, Gisela; Rodrigues, Diana; Morgan, Peter J; McCaffery, Peter

    2016-03-01

    Thyroid hormone (TH) is essential for adult brain function and its actions include several key roles in the hypothalamus. Although TH controls gene expression via specific TH receptors of the nuclear receptor class, surprisingly few genes have been demonstrated to be directly regulated by TH in the hypothalamus, or the adult brain as a whole. This study explored the rapid induction by TH of retinaldehyde dehydrogenase 1 (Raldh1), encoding a retinoic acid (RA)-synthesizing enzyme, as a gene specifically expressed in hypothalamic tanycytes, cells that mediate a number of actions of TH in the hypothalamus. The resulting increase in RA may then regulate gene expression via the RA receptors, also of the nuclear receptor class. In vivo exposure of the rat to TH led to a significant and rapid increase in hypothalamic Raldh1 within 4 hours. That this may lead to an in vivo increase in RA is suggested by the later induction by TH of the RA-responsive gene Cyp26b1. To explore the actions of RA in the hypothalamus as a potential mediator of TH control of gene regulation, an ex vivo hypothalamic rat slice culture method was developed in which the Raldh1-expressing tanycytes were maintained. These slice cultures confirmed that TH did not act on genes regulating energy balance but could induce Raldh1. RA has the potential to upregulate expression of genes involved in growth and appetite, Ghrh and Agrp. This regulation is acutely sensitive to epigenetic changes, as has been shown for TH action in vivo. These results indicate that sequential triggering of two nuclear receptor signalling systems has the capability to mediate some of the functions of TH in the hypothalamus. GLIA 2016;64:425-439. PMID:26527258

  20. Downregulation of de Novo Fatty Acid Synthesis in Subcutaneous Adipose Tissue of Moderately Obese Women

    Science.gov (United States)

    Guiu-Jurado, Esther; Auguet, Teresa; Berlanga, Alba; Aragonès, Gemma; Aguilar, Carmen; Sabench, Fàtima; Armengol, Sandra; Porras, José Antonio; Martí, Andreu; Jorba, Rosa; Hernández, Mercè; del Castillo, Daniel; Richart, Cristóbal

    2015-01-01

    The purpose of this work was to evaluate the expression of fatty acid metabolism-related genes in human adipose tissue from moderately obese women. We used qRT-PCR and Western Blot to analyze visceral (VAT) and subcutaneous (SAT) adipose tissue mRNA expression involved in de novo fatty acid synthesis (ACC1, FAS), fatty acid oxidation (PPARα, PPARδ) and inflammation (IL6, TNFα), in normal weight control women (BMI < 25 kg/m2, n = 35) and moderately obese women (BMI 30–38 kg/m2, n = 55). In SAT, ACC1, FAS and PPARα mRNA expression were significantly decreased in moderately obese women compared to controls. The downregulation reported in SAT was more pronounced when BMI increased. In VAT, lipogenic-related genes and PPARα were similar in both groups. Only PPARδ gene expression was significantly increased in moderately obese women. As far as inflammation is concerned, TNFα and IL6 were significantly increased in moderate obesity in both tissues. Our results indicate that there is a progressive downregulation in lipogenesis in SAT as BMI increases, which suggests that SAT decreases the synthesis of fatty acid de novo during the development of obesity, whereas in VAT lipogenesis remains active regardless of the degree of obesity. PMID:26694359

  1. Confinement-induced vitrification in polyethylene terephthalate

    Science.gov (United States)

    Baltá Calleja, F. J.; di Marco, G.; Flores, A.; Pieruccini, M.

    2007-06-01

    Dynamic mechanical thermal analysis performed on cold-drawn polyethylene terephthalate (PET), cold crystallized (annealed) in the temperature interval 100-140°C , reveals the presence of marginally glassy domains above the annealing temperature Ta . This suggests that the thermodynamic force driving crystallization causes the structural arrest of some noncrystalline domains. The latter thus need a temperature higher than Ta to completely defreeze. Differential scanning calorimetry supports this point of view. Analogous investigations on unoriented PET, cold crystallized in the same conditions, do not show the same peculiarities; thus, chain orientation is relevant to vitrification. This phenomenology is first cast in the language of thermodynamics by introducing an excess chemical potential δμ describing the presence of structural constraints in the amorphous domains and the effect of chain orientation. For a first test of this picture, the orientation contribution to δμ is calculated by means of the Gaussian chain model (this implicitly assumes that δμ is related to the density fluctuations). The resulting expression is then used to discuss the structural differences between cold-drawn and unoriented PET samples reported in the literature.

  2. Synthesis of docosahexaenoic acid from eicosapentaenoic acid in retina neurons protects photoreceptors from oxidative stress.

    Science.gov (United States)

    Simón, María Victoria; Agnolazza, Daniela L; German, Olga Lorena; Garelli, Andrés; Politi, Luis E; Agbaga, Martin-Paul; Anderson, Robert E; Rotstein, Nora P

    2016-03-01

    Oxidative stress is involved in activating photoreceptor death in several retinal degenerations. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in the retina, protects cultured retina photoreceptors from apoptosis induced by oxidative stress and promotes photoreceptor differentiation. Here, we investigated whether eicosapentaenoic acid (EPA), a metabolic precursor to DHA, had similar effects and whether retinal neurons could metabolize EPA to DHA. Adding EPA to rat retina neuronal cultures increased opsin expression and protected photoreceptors from apoptosis induced by the oxidants paraquat and hydrogen peroxide (H2 O2 ). Palmitic, oleic, and arachidonic acids had no protective effect, showing the specificity for DHA. We found that EPA supplementation significantly increased DHA percentage in retinal neurons, but not EPA percentage. Photoreceptors and glial cells expressed Δ6 desaturase (FADS2), which introduces the last double bond in DHA biosynthetic pathway. Pre-treatment of neuronal cultures with CP-24879 hydrochloride, a Δ5/Δ6 desaturase inhibitor, prevented EPA-induced increase in DHA percentage and completely blocked EPA protection and its effect on photoreceptor differentiation. These results suggest that EPA promoted photoreceptor differentiation and rescued photoreceptors from oxidative stress-induced apoptosis through its elongation and desaturation to DHA. Our data show, for the first time, that isolated retinal neurons can synthesize DHA in culture. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in retina photoreceptors, and its precursor, eicosapentaenoic acid (EPA) have multiple beneficial effects. Here, we show that retina neurons in vitro express the desaturase FADS2 and can synthesize DHA from EPA. Moreover, addition of EPA to these cultures protects photoreceptors from oxidative stress and promotes their differentiation through its metabolization to DHA. Cover Image for this issue: doi: 10.1111/jnc.13308. PMID:26662863

  3. Synthesis and anticancer activity of nordihydroguaiaretic acid (NDGA) and analogues.

    Science.gov (United States)

    McDonald, R W; Bunjobpon, W; Liu, T; Fessler, S; Pardo, O E; Freer, I K; Glaser, M; Seckl, M J; Robins, D J

    2001-12-01

    Nordihydroguaiaretic acid (NDGA) 1 is a constituent of the creosote bush Larrea divaricata and is well known to be a selective inhibitor of lipoxygenases. NDGA can also inhibit the platelet derived growth factor receptor and the protein kinase C intracellular signalling family, which both play an important role in proliferation and survival of cancers. Moreover, NDGA induces apoptosis in tumour xenografts. Although it is likely to have several targets of action, NDGA is well tolerated in animals. These encouraging results have prompted interest in the compound for clinical study. However, high concentrations of NDGA are required for efficacy and more potent analogues are required. We have synthesized five analogues of NDGA with different lengths of carbon bridge between the two catechol moieties in order to establish the spacing required for optimum anticancer effect and to compare their activities with NDGA. In order to ascertain if the catechol moieties are essential for anticancer activity, we prepared five analogues of NDGA containing only one hydroxyl group on each aromatic ring. NDGA 1, its racemic form 2, the catechol derivatives 5, 6 with five or six carbon atom bridges and the phenol analogues 8-11 with bridges of three to six carbon atoms all showed similar activity, with IC50 values of approximately 3-5 microM against the H-69 small cell lung cancer cell line. Analogues with shorter (3) or longer bridges (7, 12) were much less active. The most potent analogue was the biscatechol with a four-carbon bridge 4 which was > 10 times more active than NDGA and therefore represents a new lead compound in this area. Surprisingly, the tetramethyl ether 14 of this compound was slightly more active than NDGA, but the trihydroxy analogue 13 was less active than NDGA. The conformationally restricted analogue 15 was also less active than NDGA. In summary, simplification of the structure of NDGA by removal of the methyl groups has produced a new lead compound 4, which is >10 times more potent than NDGA as a proliferative inhibitor of H-69 small cell lung cancer cells. PMID:12375879

  4. Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

    Science.gov (United States)

    Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

  5. Synthesis of optically active dodecaborate-containing L-amino acids for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Kusaka, Shintaro [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai (Japan); Hattori, Yoshihide, E-mail: y0shi_hattori@riast.osakafu-u.ac.jp [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai (Japan); Uehara, Kouki; Asano, Tomoyuki [Stella Pharma Corporation, ORIX Kouraibashi Bldg. 5F 3-2-7 Kouraibashi, Chuo-ku, Osaka (Japan); Tanimori, Shinji; Kirihata, Mitsunori [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai (Japan)

    2011-12-15

    A convenient and simple synthetic method of dodecaboratethio-L-amino acid, a new class of tumor-seeking boron carrier for BNCT, was accomplished from S-cyanoethylthioundecahydro-closo-dodecaborate (S-cyanoethyl-{sup 10}BSH, [{sup 10}B{sub 12}H{sub 11}]{sup 2-}SCH{sub 2}CH{sub 2}CN) and bromo-L-{alpha}-amino acids by nearly one step S-alkylation. An improved synthesis of S-cyanoethyl-{sup 10}BSH, a key starting compound for S-alkylation, was also performed by Michael addition of {sup 10}BSH with acryronitrile in high yield. Four kinds of new dodecaboratethio-L-amino acids were obtained in optically pure form without the need for any optical resolution.

  6. The synthesis and evaluation of radioiodinated 14-(iodophenyl)-3-(R,S)methyltetradecanoic acid

    International Nuclear Information System (INIS)

    Radiohalogenated fatty acids (FA) labelled with gamma-emitting isotopes have a potentially important application in studies of impaired myocardial perfusion and metabolism. Evaluation of straight-chain fatty acids radiolabelled in different positions on the FA chain has been reported by many groups. The synthesis, labelling and preliminary evaluation of 131I- and 123I-14-(iodophenyl)-3-(R,S)methyltetradecanoic acid (I-PBMTA) are reported. This radiolabel concentrates in the mouse myocardium with 16% injected dose g-1 and 11% injected dose g-1 at 15 and 30 min, respectively. The images of the canine heart postinjection indicate a high myocardial extraction of the label with activity retained over an hour. The rate of washout of the activity from the heart was very low. This analogue is a potential agent for myocardial imaging studies. (author)

  7. Radiation synthesis of hydrogels with diprotic acid moieties and their use in the adsorption of biomolecules

    CERN Document Server

    Sen, M

    1996-01-01

    Radiation synthesis of diprotic acid moieties containing poly (N-vinyl 2- pyrrolidone) and polyacrylamide hydrogels and their use in the adsorption of biomolecules such as enzymes, proteins and drugs have been investigated. Hydrogels with varying cross-linked densities and ionic moieties were prepared from the ternary systems of N-vinyl 2-pyrrolidone/itaconic acid/water and acrylamide/maleic acid/water by irradiating with gamma rays at ambient temperature. For the characterization of network structure of hydrogels new equations were derived. Determination of average molecular weight between cross-links of hydrogels sensitive to pH changes of the swelling medium was investigated. In order to explain the influence of other external stimuli such as temperature and ionic strength of the swelling medium and the type of the buffer solution on the equilibrium swelling properties were investigated. The effect of these external stimuli on the biomolecule adsorption capacity of hydrogels were investigated for bovine se...

  8. Poly(aniline-co--aminobenzoic acid) deposited on poly(vinyl alcohol): Synthesis and characterization

    Indian Academy of Sciences (India)

    S Adhikari; P Banerji

    2013-08-01

    In this work, we have deposited poly(aniline-co--aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ polymerization. The polymerization was effected within maleic acid (MA) cross-linked PVA hydrogel. The copolymer was obtained by oxidative polymerization of aniline hydrochloride and -aminobenzoic acid using ammonium persulfate as an oxidant. Instead of conventional solution polymerization, here synthesis was carried out on APS soaked MA cross-linked PVA (MA–PVA) film where the polymer was in situ deposited in its conducting form. The composite film was characterized by Fourier transform infra red (FT–IR) and ultraviolet visible (UV–VIS) spectroscopy and electrical measurements. Surface morphology of the composite films was studied by field emission scanning electron microscopy (FESEM). The variation of conductivity of the films was studied.

  9. Hybrid Compounds Strategy in the Synthesis of Oleanolic Acid Skeleton-NSAID Derivatives

    Directory of Open Access Journals (Sweden)

    Anna Pawełczyk

    2016-04-01

    Full Text Available The current study focuses on the synthesis of several hybrid individuals combining a natural oleanolic acid skeleton and synthetic nonsteroidal anti-inflammatory drug moieties (NSAIDs. It studied structural modifications of the oleanolic acid structure by use of the direct reactivity of hydroxyl or hydroxyimino groups at position C-3 of the triterpenoid skeleton with the carboxylic function of anti-inflammatory drugs leading to new perspective compounds with high potential pharmacological activities. Novel ester- and iminoester-type derivatives of oleanolic unit with the different NSAIDs, such as ibuprofen, aspirin, naproxen, and ketoprofen, were obtained and characterized. Moreover, preliminary research of compounds obtaining structure stability under acidic conditions was examined and the PASS method of prediction of activity spectra for substances was used to estimate the potential biological activity of these compounds.

  10. Hybrid Compounds Strategy in the Synthesis of Oleanolic Acid Skeleton-NSAID Derivatives.

    Science.gov (United States)

    Pawełczyk, Anna; Olender, Dorota; Sowa-Kasprzak, Katarzyna; Zaprutko, Lucjusz

    2016-01-01

    The current study focuses on the synthesis of several hybrid individuals combining a natural oleanolic acid skeleton and synthetic nonsteroidal anti-inflammatory drug moieties (NSAIDs). It studied structural modifications of the oleanolic acid structure by use of the direct reactivity of hydroxyl or hydroxyimino groups at position C-3 of the triterpenoid skeleton with the carboxylic function of anti-inflammatory drugs leading to new perspective compounds with high potential pharmacological activities. Novel ester- and iminoester-type derivatives of oleanolic unit with the different NSAIDs, such as ibuprofen, aspirin, naproxen, and ketoprofen, were obtained and characterized. Moreover, preliminary research of compounds obtaining structure stability under acidic conditions was examined and the PASS method of prediction of activity spectra for substances was used to estimate the potential biological activity of these compounds. PMID:27077841

  11. 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...... 0.45 with respect to acetaldehyde, and the apparent activation energy was 33.8kJ/mol. The proposed oxidation of acetaldehyde with hydroxyl in the elementary rate determining step is consistent with these both. Density Functional Theory (DFT) calculations show the preference of water cleavage at the...

  12. Synthesis, purification and characterization of [3,5 - T] p-aminobenzoic acid

    International Nuclear Information System (INIS)

    This paper refers to the synthesis, purification and characterization of [3,5-T] p-aminobenzoic acid (PAB,H' vitamine). The p-aminobenzoic acid is used in the treatment of rheumatic arthritis and dermatological affections. The advantage of tritium labelling of p-aminobenzoic acid is that some biomedical important aspects of collagen's behaviour are made clear. The PAB stimulate the grow of intestinal bacteria so necessary to synthesis of some vitamins (bio tine, pantothenic acid). Tritium is the only radioactive isotope of hydrogen. Several steps have to be carried out in the synthesis of the final product as well as to study its biological behavior. For the labelling of PAB one prefers the substitution of bromine from PAB-3,5-Br with tritium because of simplicity of reaction and the easy synthesis of halogen compound. The first step in synthesis is the protection of NH2 group through acetylation of PAB. After that PAB is bromated into the 3 and 5 position with elementary bromine. The raw compound is purified and recrystallized and characterized through thin layer chromatography.The tritium labelling is performed through substitution of bromine from bromate derivative, using Pd/C (10% Pd) as catalyst and low basic conditions for the neutralization of HBr resulting from reaction. After the separation of PAB-3,5-T through filtration, the catalyst remains on the filter paper and the labelled compound goes in aqueous solution. PAB-3,5-T is purified through thin layer chromatography with the solvent system n-BuOH:NH4OH(25%):H2O:EtOH (8:1:2:2,5, v/v) with silica gel GF254 as support. The determination of activity is carried out with LSC (Liquid Scintillation Counter). A 98% purity was determined through TLC in the same conditions while determination of activity distribution was performed with a 2π Berthold scanner with gas running and without window. The chemical concentration has been measured through UV spectrophotometry and by comparing extinction with calibration curve of the pure compound. (authors)

  13. Effects on cell growth processes (mitosis, synthesis of nucleic acids and of proteins). Chapter 7

    International Nuclear Information System (INIS)

    A review is presented of reports of the interference of -SH radioprotective agents with cell division and with the processes of nucleic acid and protein synthesis which are a prerequisite for mitosis. Mitotic activity is inhibited to the same extent in mammalian tissues as in cultures of animal and plant cells and bacteria. With cultured cells, the toxicity and the antimitotic activity have been found to be at their highest level for intermediate concentrations of the compound and to decrease for higher and lower concentrations. Inhibition of the synthesis of nucleic acids by -SH radioprotective substances has been observed with cultures of cells and bacteria and in mammalian tissues. In vitro interactions with the structures of free DNA and nucleoprotein have also been studied. The extent to which such complexes between the protective agent and DNA or nucleoprotein occur in vivo is not known. A depression of protein synthesis has been observed, and participates in the more general inhibition of growth processes. Possible mechanisms of these effects are discussed. (U.K.)

  14. Angle dependent laser nanopatterning of poly(ethylene terephthalate) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Slepicka, P., E-mail: petr.slepicka@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic); Chaloupka, A. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic); Sajdl, P. [Department of Power Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic); Heitz, J. [Institute of Applied Physics, Johannes Kepler University, 4040 Linz (Austria); Hnatowicz, V. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez (Czech Republic); Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2011-05-01

    Interference effects can lead to the formation of ripple structures at laser-irradiated poly(ethylene terephthalate) surfaces. Poly(ethylene terephthalate) surface was irradiated with linearly polarized light of a pulsed 157 nm laser. In a certain range of irradiation parameters, the irradiation resulted in the formation of coherent ripples patterns. The dimension of the pattern depends on the angle of the laser beam incidence. The surface morphology of the nano-patterned poly(ethylene terephthalate) was analyzed by atomic force microscopy and focused ion beam-scanning electron microscopy. Oxygen concentration in the modified polymer surface was studied by angular resolved X-ray induced photo-electron spectroscopy. Gold nano-layers were consecutively sputtered onto the laser irradiated poly(ethylene terephthalate) surfaces. The morphology of the sputtered gold nano-layers was investigated with atomic force microscopy too. We found that the morphology of the gold nano-layers changes and depends on the surface pattern of the laser irradiated poly(ethylene terephthalate). Formation of gold 'nano-hills' is observed at the ridges of the ripple structures. The amount of oxygen together with the morphology of prepared polymer pattern may be the dominant factors controlling the gold layer growth. The present results are compared with those obtained earlier on PET irradiated with krypton fluoride laser.

  15. Angle dependent laser nanopatterning of poly(ethylene terephthalate) surfaces

    International Nuclear Information System (INIS)

    Interference effects can lead to the formation of ripple structures at laser-irradiated poly(ethylene terephthalate) surfaces. Poly(ethylene terephthalate) surface was irradiated with linearly polarized light of a pulsed 157 nm laser. In a certain range of irradiation parameters, the irradiation resulted in the formation of coherent ripples patterns. The dimension of the pattern depends on the angle of the laser beam incidence. The surface morphology of the nano-patterned poly(ethylene terephthalate) was analyzed by atomic force microscopy and focused ion beam-scanning electron microscopy. Oxygen concentration in the modified polymer surface was studied by angular resolved X-ray induced photo-electron spectroscopy. Gold nano-layers were consecutively sputtered onto the laser irradiated poly(ethylene terephthalate) surfaces. The morphology of the sputtered gold nano-layers was investigated with atomic force microscopy too. We found that the morphology of the gold nano-layers changes and depends on the surface pattern of the laser irradiated poly(ethylene terephthalate). Formation of gold 'nano-hills' is observed at the ridges of the ripple structures. The amount of oxygen together with the morphology of prepared polymer pattern may be the dominant factors controlling the gold layer growth. The present results are compared with those obtained earlier on PET irradiated with krypton fluoride laser.

  16. Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media

    OpenAIRE

    Moret, Séverine; Paul J. Dyson; Laurenczy, Gábor

    2014-01-01

    The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40 °C, 0.2 M formic acid can be obtained under 200 bar, however, in DMSO the same catalyst affords 1.9 M...

  17. Selective use of palmitic acid over stearic acid for synthesis of phosphatidylcholine and phosphatidylglycerol in lung

    International Nuclear Information System (INIS)

    The incorporation of [3H]palmitic acid and [14C]stearic acid into phospholipids in rabbit lung tissue was studied. Under equal molar concentrations of palmitate and stearate, palmitate was incorporated to the 1- and 2-positions of phosphatidylcholine (PC) and phosphatidylglycerol (PG) 2-3 times more than stearate. By contrast, palmitate was 30% less than stearate in phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine. These results suggest that preferential utilization of palmitate over stearate, rather than substrate availability, determines the high content of palmitoyl at the 1- and 2-positions of PC and PG in lung

  18. SYNTHESIS AND CHARACTERIZATION OF A NOVEL SOLID ACID CATALYST FOR IMPROVED USE OF WASTE OIL FEEDSTOCK FOR BIODIESEL PRODUCTION

    Science.gov (United States)

    Carbon Catalyst Synthesis - Sucrose was treated directly with excess sulfuric acid sulfuric acid (9:1 mol/mol, 25C). A carbon foam (nearly 20 fold increase in bulk volume) was immediately formed. The foam was then washed until no sulfate was dete...

  19. Glycerine and levulinic acid: renewable co-substrates for the fermentative synthesis of short-chain poly(hydroxyalkanoate) biopolymers

    Science.gov (United States)

    Glycerine and levulinic acid were used alone and in combination for the fermentative synthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/V) biopolymers. Shake-flask cultures of Pseudomonas oleovorans NRRL B-14682 containing different glycerine:levulinic acid ratios (1%, w/v total carbon ...

  20. Diastereoselective radical addition to ?-alkyl-?-methylene-?-butyrolactams and the synthesis of a chiral pyroglutamic acid derivative

    Directory of Open Access Journals (Sweden)

    Tomoko Yajima

    2013-07-01

    Full Text Available The cis- and trans-stereoselective radical additions to ?-methylene-?-alkyl- ?-lactams were investigated and the scope and limitation of the reaction were also revealed. This stereoselective radical reaction was used for synthesis of chiral pyroglutamic acid derivatives starting from a commercially available chiral amino acid.

  1. Manganese-catalyzed synthesis of cis-?-amino acid esters through organometallic C-H activation of ketimines.

    Science.gov (United States)

    Liu, Weiping; Zell, Daniel; John, Michael; Ackermann, Lutz

    2015-03-23

    Manganese-catalyzed C?H functionalization reactions of ketimines set the stage for the expedient synthesis of cis-?-amino acid esters through site- and regioselective alkene annulations. The organometallic C?H activation occurred efficiently with high functional group tolerance, delivering densely functionalized ?-amino acid derivatives with ample scope. PMID:25663350

  2. SYNTHESIS AND CHARACTERIZATION OF A NOVEL SOLID ACID CATALYST FOR IMPROVED USE OF WASTE OIL FEEDSTOCK FOR BIODIESEL PRODUCTION

    Science.gov (United States)

    Carbon Catalyst Synthesis - Sucrose was treated directly with excess sulfuric acid sulfuric acid (9:1 mol/mol, 25°C). A carbon foam (nearly 20 fold increase in bulk volume) was immediately formed. The foam was then washed until no sulfate was dete...

  3. Application Of Formohydroxamic Acid In Nuclear Processing: Synthesis And Complexation With Technetium-99

    International Nuclear Information System (INIS)

    Acetohydroxamic acid (AHA) is an organic ligand planned for use in the Uranium Extraction (UREX) process. It reduces neptunium and plutonium, and the resultant hydrophilic complexes are separated from uranium by extraction with tributyl phosphate (TBP) in a hydrocarbon diluent. AHA undergoes hydrolysis to acetic acid which will impede the recycling of nitric acid. During recent discussions of the UREX process, it has been proposed to replace AHA by formohydroxamic acid (FHA). FHA will undergo hydrolysis to formic acid which is volatile, thus allowing the recycling of nitric acid. The reported reduction potentials of AHA and pertechnetate (TcO4-) indicated that it may be possible for AHA to reduce technetium, altering its fate in the fuel cycle. At UNLV, it has been demonstrated that TcO4- undergoes reductive nitrosylation by AHA under a variety of conditions. The resulting divalent technetium is complexed by AHA to form the pseudo-octahedral trans-aquonitrosyl (diacetohydroxamic)-technetium(II) complex ((TcII(NO)(AHA)2H2O)+). In this paper, we are reporting the synthesis of FHA and its complex formation with technetium along with the characterization of FHA crystals achieved by NMR and IR spectroscopy. Two experiments were conducted to investigate the complexation of FHA with Tc and the results were compared with previous data on AHA. The first experiment involved the elution of Tc from a Reillex HP anion exchange resin, and the second one monitored the complexation of technetium with FHA by UV-visible spectrophotometry.

  4. Effect of penicillin on fatty acid synthesis and excretion in Streptococcus mutans BHT

    Energy Technology Data Exchange (ETDEWEB)

    Brissette, J.L.; Pieringer, R.A.

    1985-03-01

    Treatment of exponentially growing cultures of Streptococcus mutans BHT with growth-inhibitory concentrations (0.2 microgram/ml) of benzylpenicillin stimulates the incorporation of (2-/sup 14/C) acetate into lipids excreted by the cells by as much as 69-fold, but does not change the amount of /sup 14/C incorporated into intracellular lipids. At this concentration of penicillin cellular lysis does not occur. The radioactive label is incorporated exclusively into the fatty acid moieties of the glycerolipids. During a 4-hr incubation in the presence of penicillin, the extracellular fatty acid ester concentration increases 1.5 fold, even though there is no growth or cellular lysis. An indication of the relative rate of fatty acid synthesis was most readily obtained by placing S. mutans BHT in a buffer containing /sup 14/C-acetate. Under these nongrowing conditions free fatty acids are the only lipids labeled, a factor which simplifies the assay. The addition of glycerol to the buffer causes all of the nonesterified fatty acids to be incorporated into glycerolipid. The cells excrete much of the lipid whether glycerol is present or not. Addition of penicillin to the nongrowth supporting buffer system does not stimulate the incorporation of (/sup 14/C)-acetate into fatty acids.

  5. Effect of penicillin on fatty acid synthesis and excretion in Streptococcus mutans BHT

    International Nuclear Information System (INIS)

    Treatment of exponentially growing cultures of Streptococcus mutans BHT with growth-inhibitory concentrations (0.2 microgram/ml) of benzylpenicillin stimulates the incorporation of [2-14C] acetate into lipids excreted by the cells by as much as 69-fold, but does not change the amount of 14C incorporated into intracellular lipids. At this concentration of penicillin cellular lysis does not occur. The radioactive label is incorporated exclusively into the fatty acid moieties of the glycerolipids. During a 4-hr incubation in the presence of penicillin, the extracellular fatty acid ester concentration increases 1.5 fold, even though there is no growth or cellular lysis. An indication of the relative rate of fatty acid synthesis was most readily obtained by placing S. mutans BHT in a buffer containing 14C-acetate. Under these nongrowing conditions free fatty acids are the only lipids labeled, a factor which simplifies the assay. The addition of glycerol to the buffer causes all of the nonesterified fatty acids to be incorporated into glycerolipid. The cells excrete much of the lipid whether glycerol is present or not. Addition of penicillin to the nongrowth supporting buffer system does not stimulate the incorporation of [14C]-acetate into fatty acids

  6. The Influence of Tallow on Rumen Metabolism, Microbial Biomass Synthesis and Fatty Acid Composition of Bacteria and Protozoa

    DEFF Research Database (Denmark)

    Weisbjerg, Martin Riis; Børsting, Christian Friis; Hvelplund, Torben

    1992-01-01

    Rumen metabolism, microbial biomass synthesis and microbial long chain fatty acid composition were studied in lactating cows fed at two levels of dry matter intake (L, 8.6 kg DM and H, 12.6 kg DM) with 0, 4 and 6% added tallow at the low feed level (L0, L4 and L6) and 0, 2, 4 and 6% at the high...... bacterial and protozoal dry matter increased with increased tallow level, especially due to an increase in fatty acids originating from the feeds. Microbial synthesis in the rumen and flow of amino acids to the duodenum was highest for medium fat intake at the high feed level....

  7. Synthesis and antimicrobial activities of new higher amino acid Schiff base derivatives of 6-aminopenicillanic acid and 7-aminocephalosporanic acid

    Science.gov (United States)

    Özdemir (nee Güngör), Özlem; Gürkan, Perihan; Özçelik, Berrin; Oyardı, Özlem

    2016-02-01

    Novel β-lactam derivatives (1c-3c) (1d-3d) were produced by using 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and the higher amino acid Schiff bases. The synthesized compounds were characterized by elemental analysis, IR, 1H/13C NMR and UV-vis spectra. Antibacterial activities of all the higher amino acid Schiff bases (1a-3a) (1b-3b) and β-lactam derivatives were screened against three gram negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Acinetobacter baumannii RSKK 02026), three gram positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 07005, Bacillus subtilis ATCC 6633) and their drug-resistant isolates by using broth microdilution method. Two fungi (Candida albicans and Candida krusei) were used for antifungal activity.

  8. Synthesis of a metabolically stable modified long-chain fatty acid salt and its photolabile derivative

    International Nuclear Information System (INIS)

    An analogue of the long-chain fatty acid salt, sodium stearate, was synthesized in which the hydrogen atoms at carbons 2, 3, and 18 were replaced by fluorine. The key step in the synthesis was the addition of 3-iodo-2,2,3,3-tetrafluoropropanoic acid amide to 15,15,15-trifluoro-1-pentadecene. Radioactivity was introduced by catalytic reduction of 2,2,3,3,18,18,18-heptafluoro-4-octadecenoic acid amide with carrier-free tritium gas yielding a product with the specific radioactivity of 2.63 TBq/mmol. The resulting 2,2,3,3,18,18,18-heptafluoro-4-octadecenoic acid has a pKa of about 0.5 and is completely dissociated under normal physiological conditions. The fluorinated fatty acid salt analogue is readily taken up into hepatocytes and proved to be metabolically inert. In an approach to the identification of proteins involved in long-chain fatty acid salt transport across membranes and intracellular compartments, the photolabile derivative 11,11-azo-2,2,3,3,18,18,18-heptafluoro[G-3H]octadecanoic acid sodium salt was synthesized with a specific radioactivity of 2.63 TBq/mmol. Photolysis of the photolabile derivative, using a light source with a maximum emission at 350 nm, occurred with a half-life of 1.5 min. The generated carbene reacted with 14C-labeled methanol and acetonitrile with covalent bond formation of 6-13%. Its efficacy for photoaffinity labeling was demonstrated by incorporation into serum albumin, the extracellular fatty acid salt-binding protein, as well as into the intracellular fatty acid salt-binding protein (FABP) of rat liver with the molecular weight of 14,000

  9. 76 FR 18519 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Amended Final Results of...

    Science.gov (United States)

    2011-04-04

    ... Value and Antidumping Duty Order: Polyethylene Terephthalate Film, Sheet, and Strip (PET Film) from... terephthalate film, sheet, and strip (PET Film) from Taiwan.\\1\\ The period of review (POR) is July 1, 2008... Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty Administrative Review, 76...

  10. 78 FR 45512 - Polyethylene Terephthalate Film from India and Taiwan: Extension of Time Limits for Preliminary...

    Science.gov (United States)

    2013-07-29

    ... antidumping duty (AD) orders on polyethylene terephthalate film (PET Film) from India and Taiwan, pursuant to... International Trade Administration Polyethylene Terephthalate Film from India and Taiwan: Extension of Time... Antidumping Duty Orders on Polyethylene Terephthalate Film from India and Taiwan: Adequacy...

  11. 75 FR 81574 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of...

    Science.gov (United States)

    2010-12-28

    ... Countervailing Duty Order: Polyethylene Terephthalate Film, Sheet and Strip (PET Film) from India, 67 FR 44179... Countervailing Duty Determination: Bottle-Grade Polyethylene Terephthalate (PET) Resin From India, ] 70 FR 13460... Terephthalate Film, Sheet and Strip (PET Film) From India, 67 FR 34905 (May 16, 2002),......

  12. 78 FR 35245 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Final...

    Science.gov (United States)

    2013-06-12

    ... review of the antidumping duty order on polyethylene terephthalate film, sheet, and strip (``PET film... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic... review (``POR'') is November 1, 2010, through October 31, 2011. \\1\\ See Polyethylene Terephthalate...

  13. 76 FR 27005 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Initiation and...

    Science.gov (United States)

    2011-05-10

    ... order on polyethylene terephthalate film, sheet and strip (PET film) from the Republic of Korea (Korea... court decision and amended final determination on PET film from Korea. See Polyethylene Terephthalate... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of...

  14. 76 FR 57715 - Polyethylene Terephthalate Film, Sheet, and Strip From the Republic of Korea: Revocation of...

    Science.gov (United States)

    2011-09-16

    ... reasonably foreseeable time. See Polyethylene Terephthalate (PET) Film From Korea, 76 FR 54791 (September 2, 2011), and USITC Publication 4254 (August 2011), entitled Polyethylene Terephthalate (PET) Film from... Terephthalate Film, Sheet, and Strip From the Republic of Korea, 56 FR 25669 (June 5, 1991). On September...

  15. 21 CFR 878.5000 - Nonabsorbable poly(ethylene terephthalate) surgical suture.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonabsorbable poly(ethylene terephthalate... Devices § 878.5000 Nonabsorbable poly(ethylene terephthalate) surgical suture. (a) Identification. Nonabsorbable poly(ethylene terephthalate) surgical suture is a multifilament, nonabsorbable, sterile,...

  16. Synthesis and disappearance of cholesterol and bile acids in miniature swine

    International Nuclear Information System (INIS)

    Minerature swine were fitted with indwelling cannulae at two sites in the gut and catheters in the aorta, portal vein and posterior vena cava. Radioactive acetate, alanine and glucose were administered via the duodenal cannula or the portal vein catheter and synthesis of cholesterol by gut or liver monitored via the aortic serum cholesterol specific activity. Ring labeled cholesterol was administered via jejunum and portal vein and various parameters of disappearance measured during 17 to 66 days. Conversion of cholesterol to bile acids and their subsequent disappearance from gut lumen were measured. Differences were observed in substrate preference of gut and liver and in fate of newly synthesized cholesterol. Cholesterol disappearance was found to follow a two component exponential in serum and a three component exponential in gut. Serum curves were similar to those reported for humans. Two hepatic pools of cholesterol, one accessible to lipoprotein synthesis (anabolic) and another accessible to enterohepatic circulation and 7-?-hydroxylase, were inducated

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

    Directory of Open Access Journals (Sweden)

    Milosavljevi? Nedeljko B.

    2011-01-01

    Full Text Available 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 the degree of swelling and contraction of hydrogels owing to the different ionization of the ionic groups presence in hydrogel. The values of diffusion exponent, n, indicate non-Fickian kinetics corresponding to diffusion and relaxation of polymer chains. These hydrogels could be classified as macroporous hydrogels. Hence, it is possible to synthetize hydrogels of desired functionality which allow their application in different fields.

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

    Directory of Open Access Journals (Sweden)

    Genusova T.N.

    2013-09-01

    Full Text Available The paper compares low-temperature techniques for boron carbide synthesis. Boron carbide was synthesized via reaction between boric acid and various carbon precursors, e.g. phenol-formaldehyde resin, sucrose, 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 diffraction (XRD and scanning electron microscopy. Possible boron carbide yields up to 95 % of the theoretical yield as calculated from initial boron contents at temperatures of 1550 oС were demonstrated. XRD confirmed that the synthesized boron carbide (B4C has a rhombohedral crystalline structure. Final product morphology may be tailored, ranging from isometric to needle-like crystallite morphology. Nanopowders as processed via high-energy milling may be further used as sintering additive for processing of boron carbide ceramics.

  19. Facile synthesis of graphene from graphite using ascorbic acid as reducing agent

    Science.gov (United States)

    Andrijanto, Eko; Shoelarta, Shoerya; Subiyanto, Gatot; Rifki, Sadur

    2016-04-01

    Graphene has attracted a tremendous attention in recent years due to its unique properties such as mechanical, thermal, optical and electrical properties. However, a large scale production of this material is still an issue and subjected to intense research efforts. Here, we show a simple and green approach of the graphene synthesis from graphene oxide using ascorbic acid as reduction agent. A facile synthesis of graphene (rGO) through chemical oxidation of graphite into graphene oxide (GO) was described using modified Hummers method (Improved Tour Method/ITM). The ITM method does not produce toxic gas and the temperature of the oxidation is easily controlled using ice bath. The synthesized of graphene oxide was highly soluble and stable in water. The reduction of graphene oxide into graphene was performed using ascorbic acid (AA) in mild condition. The combined ITM method and green reduction using ascorbic acid open the avenue of replacing hydrazine in the reduction of graphite oxide into graphene and may be very important step for bulk production of graphene.

  20. Synthesis and coating of nanosilver by vanillic acid and its effects on Dunaliella salina Teod.

    Directory of Open Access Journals (Sweden)

    Hajar Zamani

    2013-09-01

    Full Text Available Plant phenolics have high reducing capacity which can be exploited in the synthesis of nanomaterials. In the present study, phytoreductant vanillic acid is used to produce and coat silver nanoparticles. The effects of Ag nanoparticles on the unicellular green algae D. Salina were then investigated. Under optimum pH and temperature, silver ions were reduced to silver metal by vanillic acid. The absorption spectra of the silver nanoparticles showed a maximum band of 410 nm, which is characteristic of the surface plasmon resonance of silver nanoparticles. Dynamic light scattering (DLS showed a narrow distribution size with an average of 52 nm. High concentrations of Ag nanoparticles reduced growth, total carotenoids, chlorophyll content, phenolics and antioxidant activity of the algae. Based on these results, phytoreductant vanillic acid can be used for synthesis and coating of nanosilver. Due to the projected increase in quantities and types of nanomaterials which leads to their elevated release into the environment and also because of the toxicity of nanomaterials, an urgent need to evaluate the impacts of nano-sized particles on the environment and living organisms is felt.