Sample records for terephthalic acid synthesis

  1. Synthesis and Verification of Biobased Terephthalic Acid from Furfural

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


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

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


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

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

    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: [Department of Chemistry, Vivekananda Mahavidyalaya, Burdwan, 713103 WB (India)


    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.

  4. Synthesis and Characterization of Nanosized Uranyl Coordination Polymers derived from Terephthalic acid and Azoles

    Maged S.Al-Fakeh


    Full Text Available The structure of the complexes [UO2(TPA(Azole(H2O].xH2O, TPA = 1,4-benzenedicarboxylic acid and azoles = 2-aminobenzothiazole, 2-aminothiazole, 2-amino-4-methylthiazole and 2-mercaptobenzothiazole has been prepared and characterized. The structure of the complexes has been assigned based on elemental analysis, IR, electronic spectral studies, magnetic measurement, molar conductance, Scanning electron microscope (S.E.M, X-ray powder diffraction techniques investigations and thermogravimetric analysis complete the characterization of the compound. Thermogravimetry(TG, derivative thermogravimetry (DTG and differential thermal analysis (DTA have been used to study the thermal decomposition of the complexes. The kinetic parameters have been calculated making use of the Coats-Redfern and Horowitz-Metzger. The scanning electron microscope SEM photographs and particle size calculations from the powder XRD data indicate the average size of the prepared UO2(II (28-56 nm supramolecular coordination polymers in the nanoscale range. The biological screening of the compounds was also tested.

  5. Synthesis of carboxylate complexes and evaluation of their catalytic activities for polyesterification of castor oil (Ricinum communis with terephthalic acid

    Eduardo Ulisses Xavier Peres


    Full Text Available The use of castor oil (Ricinus communis has been pointed out as an interesting alternative to produce several polymers obtained from step-growth polymerization and are suitable to be used as resins and coatings. The ricinoleate metal complexes Ni[C17H34(OHCOO]2, Sn[C17H34(OHCOO]2, Co[C17H34(OHCOO]2 and Fe[C17H34(OHCOO]2 have been prepared and used as catalyst precursors for polyesterification of castor oil and terephthalic acid (TFA. The observed catalytic activity decreased in the order: Fe[C17H34(OHCOO]2 > Co[C17H34(OHCOO]2 > Sn[C17H34(OHCOO]2 > Ni[C17H34(OHCOO]2. The new polymeric materials did not show homogeneity in their chains, as indicated by their high polydispersity. Indeed, the polydispersity index value varied from 5.49 for the polymer produced in the presence of the nickel complex to 12.42 for these prepared with the cobalt compound. On the other hand, the final material presented high molecular weight, being the lower value (Mw = 13400 Da observed for the polymer prepared with the nickel complex and the highest (Mw = 36400 Da verified for the one obtained with the cobalt compound. It was observed only a glass transition temperature for all the materials, suggesting an amorphous structure of polymeric chains.

  6. Spectrofluorimetric determination of terbium with terephthalic acid


    A spectrofluorimetric method has been developed for the determination of terbium(III) based on the formation of a complex with terephthalic acid [benzene-1, 4-dicarboxylic acid (TPA)] in slightly acidic aqueous solution in the presence of gelatin. Terbium ion can form a stable complex with TPA with the stoichiometry of 1:2. The best excitation and maximum emission wavelengths are observed at 260 nm and 545 nm, respectively. The fluorescence intensity of terbium complex gets the strongest within 20 min and remains stable up to 10 h, and it is proportional to terbium(III) concentration in the range of 4.0(10(5-1.6(10(7 mol@L(1 under the optimum conditions. The fluorescence system has good selectivity, sensitivity and stability. The relative standard deviation is still within (4% in the presence of 1200-fold amounts of the other lanthanide ions when the concentration of terbium(III) is 1.0(10(6 mol@L(1 and common co-existing ions hardly interfere the determination. It has been applied to the direct fluorimetric determination of trace terbium (III) in rare earth ores and oxides.

  7. Stannous oxalate as a novel catalyst for the synthesis of polytrimethylene terephthalate


    Stannous oxalate was prepared efficiently and characterized by XRD and FT-IR. It exhibited higher catalytic activity and had profitable effect than tetrabutyl titanate and stannous octoate for the synthesis of polytrimethylene terephthalate (PTT) via esterification-route. Over this catalyst, the degree of esterification of pure terephthalic acid was up to 94.4% at 260 ℃ after 1.5 h,while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polyester, polymerized at 260 ℃,60 Pa for 2 h, was 0.8950 dL/g and 15 mol/t, respectively. Stannous oxalate was a promising catalyst for the synthesis of PTT polyester.(C) 2007 Yun Cheng Cui. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

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

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


    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 ...


    GAO Cuili; JI Quan; KONG Qingshan; XIA Yanzhi


    To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly(lactic acid-co-glycol terephthalate) (PETA), was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, 1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the TmS and TdS of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.

  10. Adsorptive Separation and Recovery of Organic Compounds from Purified Terephthalic Acid Plant Effluent

    Khachane, P.K.; Heesink, A. Bert M.; Versteeg, G.F.; Pangarkar, V.G.


    Several organic impurities formed in the p-xylene oxidation process for manufacture of terephthalic acid are carried into the aqueous effluent from the crystallization section of PTA plant of crystallizers for purified terephthalic acid (PTA). These compounds impose a burden on the effluent treatmen

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

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


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

  12. Adsorptive Separation and Recovery of Organic Compounds from Purified Terephthalic Acid Plant Effluent

    Khachane, P.K.; Heesink, A. Bert M.; Versteeg, G. F.; Pangarkar, V.G.


    Several organic impurities formed in the p-xylene oxidation process for manufacture of terephthalic acid are carried into the aqueous effluent from the crystallization section of PTA plant of crystallizers for purified terephthalic acid (PTA). These compounds impose a burden on the effluent treatment plant. Due to the presence of these impurities the recycle of aqueous effluent from crystallization section of PTA plant to the PTA crystallizer is not possible. The aim of this study is to check...

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

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


    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


    Shen-guo Wang; Kai Tang


    Poly(ethylene terephthalate)-polycaprolactone block copolymer (PCL-b-PET) is a polyester with improved biodegradability. In the present paper, a new direct copolymerization method of ε-caprolactone (ε-CL) and bishydroxyethylene terephthalate (BHET) in the presence of Ti(OBu)4 was proposed for the synthesis of PCL-b-PET. The PCL-b-PET copolymer was characterized by IR, GPC and 1H-NMR techniques, and the effects of synthesis conditions, such as temperature, reaction time and concentration of catalyst on the copolymerization were discussed.

  15. Toxicological review and oral risk assessment of terephthalic acid (TPA) and its esters: A category approach.

    Ball, Gwendolyn L; McLellan, Clifton J; Bhat, Virunya S


    Polyethylene terephthalate, a copolymer of terephthalic acid (TPA) or dimethyl terephthalate (DMT) with ethylene glycol, has food, beverage, and drinking water contact applications. Di-2-ethylhexyl terephthalate (DEHT) is a plasticizer in food and drinking water contact materials. Oral reference doses (RfDs) and total allowable concentrations (TACs) in drinking water were derived for TPA, DMT, and DEHT. Category RfD and TAC levels were also established for nine C(1)-C(8) terephthalate esters. The mode of action of TPA, and of DMT, which is metabolized to TPA, involves urinary acidosis, altered electrolyte elimination and hypercalciuria, urinary supersaturation with calcium terephthalate or calcium hydrogen terephthalate, and crystallization into bladder calculi. Weanling rats were more sensitive to calculus formation than dams. Calculi-induced irritation led to bladder hyperplasia and tumors in rats fed 1000 mg/kg-day TPA. The lack of effects at 142 mg/kg-day supports a threshold for urine saturation with calcium terephthalate, a key event for calculus formation. Chronic dietary DMT exposure in rodents caused kidney inflammation, but not calculi. Chronic dietary DEHT exposure caused general toxicity unrelated to calculi, although urine pH was reduced suggesting the TPA metabolite was biologically-active, but of insufficient concentration to induce calculi. Respective oral reference doses of 0.5, 0.5, and 0.2 mg/kg-day and total allowable drinking water concentrations of 3, 3, and 1 mg/L were derived for TPA, DMT, and DEHT. An oral RfD of 0.2 mg/kg-day for the terephthalate category chemicals corresponded to a drinking water TAC of 1 mg/L.

  16. Induction of Bladder Lesion by Terephthalic Acid and Its Mechanism


    Objective To provide more information for rational evaluation of potential risks of terephthalic acid (TPA), we studied the effects of TPA on rats' bladders in 90 days after TPA exposure. Methods Sprague Dawley rats were subdivided into five groups, ingesting 0 %, 0.04 %, 0.2 %, 1 %, and 5 % TPA respectively for a sub-chronic feeding study lasting for 90 days. Urine, serum and samples of brain, liver, lung, kidney, bladder, etc. Were collected and analyzed. Results TPA ingesting decreased the value of urinary pH, and increased the contents of Ca2+, Zn2+, Mg2+, Na+, K+ in urine. The volume of 24 h urine was significantly increased in male rats in the 1 % and 5 % TPA groups. Urinary white sediment was found in both sexes, and its formation in male rats seemed more susceptible than that in female rats. Alpha 2u-globulin (AUG) in serum and urine of male rats was markedly increased in a dose-dependent manner. Fifteen cases of hyperplasia (simple or atypical) were determined in the 5 % TPA ingesting group, 14/52 in male rats and1/23 in female rats. Among them 3 male rats had no stone or calculus. Those with either bladder stones or hyperplasia were accompanied with urinary white sediments. Conclusion White sediment accompanied with elevated urine AUG is the basis of TPA induced urolith formation, and is also associated with TPA induced bladder epithelialcell proliferation. It can act as an early biomarker for the potential toxic effect of TPA.

  17. Tetra(acetylacetonato) tin(Ⅳ) as new catalyst for polytrimethylene terephthalate synthesis


    Chelate tetra(acetylacetonato) tin(Ⅳ) was prepared and used as catalyst for polytrimethylene terephthalate synthesis.It exhibited higher catalytic activity than tetrabutyl titanate,butyltinhydroxide oxide and dibutyltin oxide.Decrease in reaction time, content of terminal carboxyl group,color intensity and increase in intrinsic viscosity were observed.The unique molecular structure can be considered as factor remarkably improving the catalytic activity of tetra(acetylacetonato) tin(Ⅳ).

  18. Evaluation of Acoustic Cavitation in Terephthalic Acid Solutions Containing Gold Nanoparticles by the Spectrofluorometry Method

    Ameneh Sazgarnia


    Full Text Available Background. When a liquid is irradiated with high intensity and low-frequency ultrasound, acoustic cavitation occurs. The existence of particles in a liquid provides nucleation sites for cavitation bubbles and leads to a decrease in the ultrasonic intensity threshold needed for cavitation onset. Materials and Methods. The study was designed to measure hydroxyl radicals in terephthalic acid solutions containing gold nanoparticles in a near field of a 1 MHz sonotherapy probe. The effect of ultrasound irradiation parameters containing mode of sonication and ultrasound intensity in hydroxyl radicals production have been investigated by the spectrofluorometry method. Results. Recorded fluorescence signal in terephthalic acid solution containing gold nanoparticles was higher than the terephthalic acid solution without gold nanoparticles. Also, the results showed that any increase in intensity of the sonication would be associated with an increase in the fluorescence intensity. Conclusion. Acoustic cavitation in the presence of gold nanoparticles has been introduced as a way for improving therapeutic effects on the tumors in sonodynamic therapy. Also, the terephthalic acid dosimetry is suitable for detecting and quantifying free hydroxyl radicals as a criterion of cavitation production over a certain range of conditions in medical ultrasound fields.

  19. High rate treatment of terephthalic acid production wastewater in a two-stage anaerobic bioreactor

    Kleerebezem, R.; Beckers, J.; Pol, L.W.H.; Lettinga, G.


    The feasibility was studied of anaerobic treatment of wastewater generated during purified terephthalic acid (PTA) production in two-stage upflow anaerobic sludge blanket (UASB) reactor system. The artificial influent of the system contained the main organic substrates of PTA-wastewater: acetate, be

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

    Georg Steinkellner


    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.

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

    Mi Lin Zhang


    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.

  2. Porous heterometallic Cd(II)-Ca(II)-terephthalate: Synthesis, structure, luminescent and gas adsorption properties

    Liu, Haiping; Dong, Yanli; Ren, Hailiang


    A new heterometallic poly(dihydrate-one and a half terephthalate-cadmium calcium) coordination polymer, namely [CdCa(pdc)1.5(H2O)2]n (1, H2pdc = terephthalic acid), has been successfully obtained by the solvothermal reactions of H2pdc, Cd(NO3)2·4H2O and Ca(NO3)2·4H2O. Single crystal X-ray diffraction analysis reveals that compound 1 features a 3D porous framework based on 1D chain subunits. Moreover, compound 1 is luminescent and exhibits high adsorption capacities for H2, CH4 and CO2 at room temperature.

  3. Investigation on injury of liver and kindey among the workers exposed to terephthalic acid, ethylene glycol and (or) dowtherm A.


    Objective: To study injury of liver and kidney among the workers exposed to terephthalic acid (TPA), ethylene glycol(EG) and (or) dowtherm A(DOW), and to research for the early biological monitoring indexes.

  4. 1-Phenyl-3-(quinolin-5-yl)urea as a host for distinction of phthalic acid and terephthalic ac

    Dipjyoti Kalita; Jubaraj B Baruah


    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.

  5. Dynamic modeling and control of industrial crude terephthalic acid hydropurification process

    Li, Zhi; Zhong, Weimin; Liu, Yang; Luo, Na; Qian, Feng [East China University of Science and Technology, Shanghai (China)


    Purified terephthalic acid (PTA) is critical to the development of the polyester industry. PTA production consists of p-xylene oxidation reaction and crude terephthalic acid (CTA) hydropurification. The hydropurification process is necessary to eliminate 4-carboxybenzaldehyde (4-CBA), which is a harmful byproduct of the oxidation reaction process. Based on the dynamic model of the hydropurification process, two control systems are studied using Aspen Dynamics. The first system is the ratio control system, in which the mass flows of CTA and deionized water are controlled. The second system is the multivariable predictive control-proportional-integral-derivative cascade control strategy, in which the concentrations of 4-CBA and carbon monoxide are chosen as control variables and the reaction temperature and hydrogen flow are selected as manipulated variables. A detailed dynamic behavior is investigated through simulation. Results show that the developed control strategies exhibit good control performances, thereby providing theoretical guidance for advanced control of industry-scale PTA production.

  6. Direct electrospray ionization mass spectrometry quantitative analysis of sebacic and terephthalic acids in biodegradable polymers.

    Rizzarelli, Paola; Zampino, Daniela; Ferreri, Loredana; Impallomeni, Giuseppe


    A direct, rapid, and easy electrospray ionization mass spectrometry (ESI-MS) method to determine concentrations of sebacic acid (SA) and terephthalic acid (TA) residues in biodegradable copolymers was developed. Copolyester samples were synthesized from 1,4-butanediol and sebacic and terephthalic acids by melt polymerization. Extraction of monomers was performed in methanol. Their concentrations were determined by direct infusion ESI-MS, without chromatographic separation, using 1,12-dodecanedioic acid (DDA) as an internal standard. Calibration curves were obtained by plotting the ratio of the areas of the peaks relative to monomers and DDA standard as a function of their concentration ratio. We validated the method by determining the concentration of TA residue using both the ESI-MS protocol and high-performance liquid chromatography (HPLC) analysis with UV detection. The linearity range and the detection limit of this assay were 0.1-5.0 and 0.01 ppm for SA and 0.1-6.0 and 0.03 ppm for TA. This assay represents a useful alternative to conventional methods currently employed for acid quantification, resulting advantageous for its speed and high sensitivity.

  7. Stannous oxalate: An efficient catalyst for poly(trimethylene terephthalate) synthesis


    A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.

  8. Condensation Polymers of Terephthalic Acid and 1,4-Diaminobutane and Their Schiff Base Complexes

    Sandeep Rai


    Full Text Available Amino-terminated oligomeric poly(tetramethylene terephthalamide (PTTA was prepared by condensation of terephthalic acid and 1,4-diaminobutane using phosphorylation technique. Schiff base complexes of this polyamide were synthesized with salicylaldehyde and 2-hydroxy-1-naphthaldehyde complexes of Co(II, Ni(II, and Cu(II. The polyamide as well as Schiff base complexes were characterized by elemental analysis, IR spectroscopy, and magnetic susceptibility measurements. Thermal stabilities of ligand and its various complexes were compared by thermogravimetric analysis.

  9. Terephthalic acid wastewater treatment by using two-stage aerobic process


    Based on the tests between anoxic and aerobic process, the two-stage aerobic process with a biological selector was chosen to treat terephthalic acid wastewater (PTA). By adopting the two- stage aerobic process, the CODCr in PTA wastewater could be reduced from 4000-6000 mg/L to below 100 mg/L; the COD loading in the first aerobic tank could reach 7.0-8.0 kgCODCr/(m3.d) and that of the second stage was from 0.2 to 0.4 kgCODCr/(m3.d). Further researches on the kinetics of substrate degradation were carried out.

  10. Segmented block copolymers based on poly(butylene terephthalate) and telechelic polyesters and polyamides of dimerized fatty acids

    Manuel, H.J.; Gaymans, R.J.


    Segmented block copolymers (SBCs) based on poly(butylene terephthalate) (PBT) and telechelics based on dimerized fatty acids have been synthesized in the melt. The dimerized fatty acids were coupled with diols or diamines to synthesize polyesters and polyamides of low molar mass. With these telechel

  11. Synthesis, crystal structure and magnetic properties of terephthalate-isophthalete- and phthalate-bridged copper (II) dinuclear complexes

    Cano, J.; De Munno, G.; Sanz, J.L.; Ruiz, R.; Lloret, F.; Faus, J.; Julve, M.


    The ability of the dianions of the terephthalic (H{sub 2}ta), isophthalic (H{sub 2} ita) and phthalic (H{sub 2} phta) acids both to act as bridges between copper (II) ions and to mediate intramolecular exchange interactions has been investigated by single crystal X-ray diffraction and variable-temperature magnetic susceptibility measurements. (Author) 31 refs.


    LI Xingui; HUANG Meirong; GUAN Guihe; SUN Tong


    Nine thermotropic liquid crystalline terpolyesters based on vanillic acid(V), p-hydroxybenzoic acid(H) and poly(ethylene terephthalate)(E) were investigated by thermogravimetry to ascertain their thermostability and the kinetic parameters for thermal degradation. Overall activation energy data of the degradation had been calculated over the range 5~70% weight loss. The temperatures and the activation energy of the degradation lie in the ranges of 384~394 ℃ at a heating rate of 1 ℃/min and 176~205 KJ/mol at the weight loss of 5%, respectively, which suggests that the terpolyesters have good thermostability.

  13. Metabolism of Terephthalic Acid and Its Effects on CYP4B1 Induction


    Objective To investgate the metabolism of terephthalic acid (TPA) in rats and its mechanism. Methods Metabolism was evaluated by incubating sodium terephthalate (NaTPA) with rat normal liver microsomes, or with microsomes pretreated by phenobarbital sodium, or with 3-methycholanthrene, or with diet control following a NADPH-generating system. The determination was performed by high performance liquid chromatography (HPLC), and the mutagenic activation was analyzed by umu tester strain Salmonella typhimurium NM2009. Expression of CYP4B 1 mRNA was detected by RT-PCR. Results The amount of NaTPA (12.5-200 μmol· L-1) detected by HPLC did not decrease in microsomes induced by NADPH-generating system. Incubation of TPA (0.025-0.1 mmol·L-1) with induced or noninduced liver microsomes in an NM2009 umu response system did not show any mutagenic activation. TPA exposure increased the expression of CYP4B 1 mRNA in rat liver, kidney, and bladder. Conclusion Lack of metabolism of TPA in liver and negative genotoxic data from NM2009 study are consistent with other previous short-term tests, suggesting that the carcinogenesis in TPA feeding animals is not directly interfered with TPA itself and/or its metabolites.

  14. Determination of the Thermal Decomposition Products of Terephthalic Acid by Using Curie-Point Pyrolyzer

    Begüm Elmas Kimyonok, A.; Ulutürk, Mehmet


    The thermal decomposition behavior of terephthalic acid (TA) was investigated by thermogravimetry/differential thermal analysis (TG/DTA) and Curie-point pyrolysis. TG/DTA analysis showed that TA is sublimed at 276°C prior to decomposition. Pyrolysis studies were carried out at various temperatures ranging from 160 to 764°C. Decomposition products were analyzed and their structures were determined by gas chromatography-mass spectrometry (GC-MS). A total of 11 degradation products were identified at 764°C, whereas no peak was observed below 445°C. Benzene, benzoic acid, and 1,1‧-biphenyl were identified as the major decomposition products, and other degradation products such as toluene, benzophenone, diphenylmethane, styrene, benzaldehyde, phenol, 9H-fluorene, and 9-phenyl 9H-fluorene were also detected. A pyrolysis mechanism was proposed based on the findings.

  15. Synthesis and properties of poly(butylene terephthalate)-b-polyisobutylene segmented block copolymers

    Walch, E.; Gaymans, R.J.


    Segmented block copolymers of polyisobutylene (PIB) and poly(butylene terephthalate) (PBT) were made by condensation polymerization of α,θ-di-anhydride telechelic PIB, with 1,4-butanediol and dimethyl terephthalate. The inherent viscosity of the polymers was between 0.35 and 2.0 dl g−1. The extracta

  16. 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.

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


    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.

  17. Fuzzy Neural Network Model of 4-CBA Concentration for Industrial Purified Terephthalic Acid Oxidation Process

    刘瑞兰; 苏宏业; 牟盛静; 贾涛; 陈渭泉; 褚健


    A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeling.First,a set of preliminary input variables is selected according to prior knowledge and experience. Secondly,a method based on the maximum correlation coefficient is proposed to detect the dead time between the process variables and response variables. Finally, the fuzzy curve method is used to reduce the unimportant input variables.The simulation results based on industrial data show that the relative error range of the FNN model is narrower than that of the American Oil Company (AMOCO) model. Furthermore, the FNN model can predict the trend of the 4-CBA concentration more accurately.

  18. Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater


    As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%-78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

  19. Multi-objective Optimization of Industrial Purified Terephthalic Acid Oxidation Process

    牟盛静; 苏宏业; 古勇; 褚健


    Multi-objective optimization of a purified terephthalic acid (PTA) oxidation unit is carried out in this paper by using a process model that has been proved to describe industrial process quite well. The model is a semiempirical structured into two series ideal continuously stirred tank reactor (CSTR) models. The optimal objectives include maximizing the yield or inlet rate and minimizing the concentration of 4-carboxy-benzaldhyde, which is the main undesirable intermediate product in the reaction process. The multi-objective optimization algorithm applied in this study is non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ). The performance of NSGA-II is further illustrated by application to the title process.

  20. Direct Silver Micro Circuit Patterning on Transparent Polyethylene Terephthalate Film Using Laser-Induced Photothermochemical Synthesis

    Chen-Jui Lan


    Full Text Available This study presents a new and improved approach to the rapid and green fabrication of highly conductive microscale silver structures on low-cost transparent polyethylene terephthalate (PET flexible substrate. In this new laser direct synthesis and pattering (LDSP process, silver microstructures are simultaneously synthesized and laid down in a predetermined pattern using a low power continuous wave (CW laser. The silver ion processing solution, which is transparent and reactive, contains a red azo dye as the absorbing material. The silver pattern is formed by photothermochemical reduction of the silver ions induced by the focused CW laser beam. In this improved LDSP process, the non-toxic additive in the transparent ionic solution absorbs energy from a low cost CW visible laser without the need for the introduction of any hazardous chemical process. Tests were carried out to determine the durability of the conductive patterns, and numerical analyses of the thermal and fluid transport were performed to investigate the morphology of the deposited patterns. This technology is an advanced method for preparing micro-scale circuitry on an inexpensive, flexible, and transparent polymer substrate that is fast, environmentally benign, and shows potential for Roll-to-Roll manufacture.

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

    Smitha Rajesh


    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.

  2. Biosynthesis of terephthalic acid, isophthalic acid and their derivatives from the corresponding dinitriles by tetrachloroterephthalonitrile-induced Rhodococcus sp.

    He, Yu-Cai; Wu, Ya-Dong; Pan, Xue-He; Ma, Cui-Luan


    The nitrilase from Rhodococcus sp. CCZU10-1 catalyses the hydrolysis of dinitriles to acids without the formation of amides and cyanocarboxylic acids. It was induced by benzonitrile and its analogues (tetrachloroterephthalonitrile > ε-caprolactam > benzonitrile > phenylacetonitrile), and had activity towards aromatic nitriles (terephthalonitrile > tetrachloroterephthalonitrile > isophthalonitrile > tetrachloroisophthalonitrile > tetrafluoroterephthalonitrile > benzonitrile). After the optimization, the highest nitrilase induction [311 U/(g DCW)] was achieved with tetrachloroterephthalonitrile (1 mM) in the medium after 24 h at 30 °C after optimum enzyme activity was at pH 6.8 and at 30 °C. Efficient biocatalyst recycling was achieved by cell immobilization in calcium alginate, with a product-to-biocatalyst ratios of 776 g terephthalic acid/g DCW and 630 g isophthalic acid/g DCW.

  3. Kinetic evaluation and process performance of an upflow anaerobic filter reactor degrading terephthalic acid.

    Davutluoglu, Orkun I; Seckin, Galip


    The anaerobic degradation of terephthalic acid (TA) as the sole organic carbon source was studied in an upflow anaerobic filter (UAF) reactor. The reactor was seeded with biomass obtained from a full-scale upflow anaerobic sludge bed (UASB) reactor and was used to treat wastewater from a petrochemical facility producing dimethyl terephthalate. The UAF reactor was operated for 252 d with a constant hydraulic retention time of 24 h, and the organic loading rate (OLR) was gradually increased from 1 to 10 g-chemical oxygen demand (COD)/L d. After a lag period of approximately 40 d, the COD removal efficiency increased exponentially and high removal rate values (≈90%) were obtained, except for at highest OLR (10 g-COD/L d). The high removal rates and the robustness of the reactor performance could be attributed to the formation of biofilm as well as granular sludge. The methane production rates (0.22 to 2.15 L/d) correlated well with the removed OLRs (0.3 to 6.8 g-COD/L d) during the various phases of treatment, indicating that the main mechanism of TA degradation occurs via methanogenic reactions. The average methane content of the produced biogas was 70.3%. The modified Stover-Kincannon model was found to be applicable for the anaerobic degradation of TA in UAFs (Umax = 64.5, KB = 69.1 g-COD/L d and Ymax = 0.27 L-CH4/g-CODremoved). These results suggest that UAF reactors are among the most effective reactor configurations for the anaerobic degradation of TA.

  4. The selective recycling of mixed plastic waste of polylactic acid and polyethylene terephthalate by control of process conditions

    Carné Sánchez , Arnau; Collinson, Simon R.


    The glycolysis of postconsumer polyethylene terephthalate (PET) waste was evaluated with catalysts of zinc acetate, zinc stearate and zinc sulfate, showing that zinc acetate was the most soluble and effective. The chemical recycling by solvolysis of polylactic acid (PLA) and PET waste in either methanol or ethanol was investigated. Zinc acetate as a catalyst was found to be necessary to yield an effective depolymerization of waste PLA giving lactate esters, while with the same reaction condit...

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

    K Sathish Kumar


    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.

  6. Lewis acid/base character and crystallisation properties of poly(butylene terephthalate).

    Santos, José M R C A; Guthrie, James T


    Two grades of poly(butylene terephthalate) were analysed by means of inverse gas chromatography (IGC) and the results correlated with the respective crystallisation properties. The following parameters were determined by IGC: the dispersive component of the surface tension, the enthalpy and the entropy of adsorption of selected polar and apolar probes, and the Lewis acidity and basicity constants, Ka and Kb respectively. The interpretation of the values determined for Ka and Kb is in agreement with the FTIR spectra relating to the carboxyl end-group and the hydroxyl end-group concentrations in these polymers. The differences in the molecular weight values and in the end-group type and concentration, between the two grades of PBT, do not cause differences in the crystallisation activation energy. This observation suggests that there is a leading contribution of the Lewis basic sites to the crystallisation activation energy of the grades of PBT that were analysed. However, the lower value of Ka and the greater molar mass of one of the PBT grades lead to a corresponding lower crystallisation degree.

  7. Anaerobic degradation of purified terephthalic acid wastewater using a novel, rapid mass-transfer circulating fluidized bed.

    Feng, Yangyang; Lu, Beibei; Jiang, Yu; Chen, Yinwen; Shen, Shubao


    The anaerobic treatability of purified terephthalic acid (PTA) wastewater in a novel, rapid mass-transfer fluidized bed reactor using brick particles as porous carrier materials was investigated. The reactor operation was stable after a short 34 day start-up period, with chemical oxygen demand (COD) removal efficiency between 65 and 75%, terephthalate (TA) removal efficiency between 60% and 70%, and system organic loading rate (OLR) increasing from 7.37 to 18.52 kg COD/m(3) d. The results demonstrate that the reactor is very efficient, and requires a low hydraulic retention time (HRT) of 8 h to remove both TA and COD from the high-concentration PTA wastewater. The system also has high resistance capacity to varied OLR.

  8. Development of biodegradable metaloxide/polymer nanocomposite films based on poly-ε-caprolactone and terephthalic acid.

    Varaprasad, Kokkarachedu; Pariguana, Manuel; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Sadiku, Emmanuel Rotimi


    The present investigation describes the development of metal-oxide polymer nanocomposite films from biodegradable poly-ε-caprolactone, disposed poly(ethylene terephthalate) oil bottles monomer and zinc oxide-copper oxide nanoparticles. The terephthalic acid and zinc oxide-copper oxide nanoparticles were synthesized by using a temperature-dependent precipitation technique and double precipitation method, respectively. The terephthalic acid synthesized was confirmed by FTIR analysis and furthermore, it was characterized by thermal analysis. The as-prepared CuO-ZnO nanoparticles structure was confirmed by XRD analysis and its morphology was analyzed by SEM/EDS and TEM. Furthermore, the metal-oxide polymer nanocomposite films have excellent mechanical properties, with tensile strength and modulus better than pure films. The metal-oxide polymer nanocomposite films that were successfully developed show a relatively brighter colour when compared to CuO film. These new metal-oxide polymer nanocomposite films can replace many non-degradable plastics. The new metal-oxide polymer nanocomposite films developed are envisaged to be suitable for use in industrial and domestic packaging applications.

  9. Catalytic Synthesis Lactobionic Acid

    V.G. Borodina


    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

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

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


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

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

    F. Malek


    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.

  12. Synthesis and characterization of azo acrylates grafted onto polyethylene terephthalate by gamma irradiation

    Bucio, Emilio [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico)]. E-mail:; Skewes, Phill [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico); Burillo, Guillermina [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico)


    Polyethylene terephthalate (PET) films were grafted with acryloyl chloride by gamma irradiation, and the grafted films were reacted with Disperse Red 1 or 4-phenylazophenol. The films where characterized by atomic force microscopy, differential scanning calorimetry, FTIR-ATR, light polarized microscopy, elemental analysis and UV spectroscopy. The surface of the films was homogeneous, and the dye underwent trans to cis photoreaction, whereby the red films became colorless by the irradiation of UV light at room temperature.

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

    Marschewski, Marcel [Institute of Energy Research and Physical Technology, Clausthal University of Technology, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Otto, Christian [Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstrasse 6, 38678 Clausthal-Zellerfeld (Germany); Wegewitz, Lienhard [Clausthal Centre of Materials Engineering, Clausthal University of Technology, Agricolastrasse 2, 38678 Clausthal-Zellerfeld (Germany); Höfft, Oliver [Institute of Electrochemistry, Clausthal University of Technology, Arnold-Sommerfeld-Str. 6, 38678 Clausthal-Zellerfeld (Germany); Schmidt, Andreas, E-mail: [Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstrasse 6, 38678 Clausthal-Zellerfeld (Germany); Maus-Friedrichs, Wolfgang, E-mail: [Institute of Energy Research and Physical Technology, Clausthal University of Technology, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Clausthal Centre of Materials Engineering, Clausthal University of Technology, Agricolastrasse 2, 38678 Clausthal-Zellerfeld (Germany)


    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.

  14. Synthesis and Characterizations of Poly(trimethylene terephthalate-b-poly(tetramethylene glycol Copolymers

    Feng Liu


    Full Text Available A series of poly(trimethylene terephthalate-b-poly(tetramethylene glycol (PTT-PTMEG copolymers were synthesized by two-step melt-polycondensation. The copolymers were characterized by using Fourier transform infrared spectroscopy (FTIR, 1H NMR spectroscopy, rheometer, differential scanning calorimetry (DSC, polarized optical microscopy (POM, thermal gravimetric analysis (TGA, and mechanical properties. The results suggest that by increasing the flexible PTMEG contents from 0% to 60 wt%, the copolymers show decreased glass transition temperatures, melting points, melt-crystallization temperatures, hardness, tensile strength, thermostability, and smaller spherulites dimensions; however it has much increased impact strength and elongation at breaking point. Compared with commercial poly(butylene terephthalate (PBT-type TPEE with 25 mol% flexible segments, PTT-type TPEE having 25 mol% flexible segments has a lower glass transition temperature, melting point, crystallization temperature, and much lower tensile strength although it has a much higher impact strength than that of PBT-type TPEE, and it is not suitably used as a commercial TPEE.


    HU Hengliang; MU Xiangqi; WU Shizhen


    The crystallization kinetics of the copolyester, poly(ethylene terephthalate) (PET) modified by sodium salt of 5-sulpho-isophthalic acid(SIPM), was investigated by means of differential scanning calorimeter. The experimental results and polari-microscopy observation all showed that the introduction of SIPM did not affect the nucleation of crystallization. Within the temperature range between their glass transition temperature Tg and melting point T., the crystallization rate of the copolyester sample decreased with increasing content of SIPM. The relative crystallization rate constant Z of SIPM/DMT (dimethyl terephthalate) 4mol % sample was about 1% pure PET's Z value. For isothermal crystallized copolyester samples, DSC heating curves displayed multi-melting behavior. This was interpreted by molecular weight fractionation during crystallization and premelting-recrystallization mechanism. This interpretation showed why the second melting point Tm2 will change according to Hoffman-Weeks(H-W) equation[1] and the first melting point Tm1 will increase with increasing SIPM. The principal cause of these phenomena is the high temperature crystallization rate decreases rapidly with increasing SIPM.

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

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


    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.

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

    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: [Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695 (United States)


    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.

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

    Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M., E-mail: [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


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

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

    Mohammed S. M. Abdelbaky


    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+.

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

    Montuori, P; Jover, E; Morgantini, M; Bayona, J M; Triassi, M


    Phthalic acid and phthalate esters are of growing interest due to their significant usage and potential toxicity. Polyethylene terephthalate (PET) and glass are both widely used materials for bottled 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 analysed in a large number of Italian bottled water samples. These samples showed different concentrations of phthalates are nearly 20 times higher in samples bottled in PET than those from glass bottles with total levels of phthalates of 3.52 and 0.19 microg l(-1), respectively. However, the observed levels do not represent a significant exposure pathway when considering the US Environmental Protection Agency (USEPA) reference dose (an estimate of a daily oral exposure to the human population, including sensitive subgroups, that is likely to be without an appreciable risk of deleterious effects during a lifetime). In addition, no significant correlation was found between the phthalate concentrations and the physicochemical properties of the different water samples, apart from the still/sparkling water parameter for the PET samples. In this instance, slightly higher concentrations were observed for the PET bottled still water samples than for the sparkling water samples, although no explanation has been found yet.

  1. Syntheses and applications of Eu(Ⅲ)complexes of 2-thienyltrifluoroacetonate, terephthalic acid and phenanthroline as light conversion agents

    ZHAO Xue-hui; HUANG Ke-long; JIAO Fei-peng; YANG You-ping; LI Zhao-jian; LIU Zhi-guo; HU Shun-qin


    A series of europium(Ⅲ)complexes of 2-thienyltrifluoroacetonate(HTTA), terephthalic acid(TPA) and phenanthroline (Phen) were synthesized.The new complexes Eu(TPA)(TTA)Phen and Eu2(TPA)(TTA)4Phen2 were characterized by elemental analysis, IR spectrum, scanning electron microscope and thermal stability analysis.The results show that the thermal stability of the Eu(Ⅲ)complexes increases in the following order: the mononuclear complex Eu(TTA)3Phen, the binuclear complex Eu2(TPA)(TTA)4Phen2, the chain polynuclear complex Eu(TPA)(TTA)Phen. And the formation of the binuclear/polynuclear structure of the new complexes appears to be responsible for the enhancement of their thermal and optical stability.In addition, The fluorescence excitation spectra of these new complexes show more broad excitation bands than that of the complex Eu(TTA)3Phen corresponding to their formation.The enhancement of Eu3+ fluorescence in the new complexes Can be observed by the addition of Gd3+.The bright red luminescent plastics carl be obtained when the complex EuGd(TPA)(TTA)4Phen2 is added above 0.5%(mass fraction).

  2. A two-stage anaerobic system for biodegrading wastewater containing terephthalic acid and high strength easily degradable pollutants


    The high strength easily biodegradable pollutants(represented by CODE) are strong inhibitors of terephthalic acid(TA) anaerobic biodegradation. At the same time, TA can inhibiteasily biodegradable pollutants removal under anaerobic conditionsto a limited extent. This mutual inhibition could happen and causea low removal efficiency of both TA and CODE, when the effluentfrom TA workshops containing TA and easily biodegradable pollutantsare treated by a single anaerobic reactor system. Based upon thetreatment kinetics analysis of both TA degradation and CODEremoval, a two-stage up-flow anaerobic sludge blanket and up-flowfixed film reactor(UASB-UAFF) system for dealing with this kind ofwastewater was developed and run successfully at laboratory scale.An UASB reactor with the methanogenic consortium as the first stageremoves the easily biodegradable pollutants(CODE). An UAFF reactor as the second stage is mainly in charge of TA degradation. At aHRT 18.5h, the CODE and TA removal rate of the system reached 89.2% and 71.6%, respectively.

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

    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: [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)


    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.

  4. One-pot Synthesis of Bis(dihydropyrimidinone-4-yl)benzene Using Boric Acid as a Catalyst

    TU Shu-Jiang; ZHU Xiao-Tong; FANG Fang; ZHANG Xiao-Jing; ZHU Song-Lei; LI Tuan-Jie; SHI Da-Qing; WANG Xiang-Shan; JI Shun-Jun


    A simple effective synthesis of bis(dihydropyrimidinone-4-yl)benzene derivatives, using boric acid as catalyst,from isophthalic aldehyde or terephthalic aldehyde, 1,3-dicarbonyl compounds and urea or thiourea in glacial acetic acid was described. As the expansion of the classical Biginelli reaction, this method has the advantage of excellent yields 83%-94% and short reaction time 0.5-1.5 h.

  5. Synthesis of PET and Its Copolymer with Rare Earth Catalysts

    张天骄; 武荣瑞


    A new catalyst system was used in the synthesis of polyethylene terephthalate(PET) and its copolymers, which involved a Ln3+ containing compound. The catalytic effects were studied, and it was found that the direct esterification reaction of terephthalate acid(TPA) with ethylene glycol(EG) can be accelerated by the addition of Ln3+ containing compound, which acts as a promoter of the catalyst Sb2O3 in polycondensation of bis hydroxyethyl terephthalate(BHET).

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

    Christoph S. Nabzdyk


    Full Text Available 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 device. PET and PGA polymers were electrospun from either a single-blended solution (ePET/ePGA-s or two separate polymer solutions (ePET/ePGA-d. ePET/ePGA-d material revealed two distinct fibers and was significantly stronger than the single fiber ePET/ePGA-s material. After 21 days of incubation in PBS, ePET-PGA-s showed fiber strand breaks likely due to the degradation of the PGA within the ePET-ePGA-s fiber, while the ePET/ePGA-d material showed intact ePET fibers even after ePGA fiber degradation. The ePET/ePGA- material was able to release red fluorescent dye for at least 14 days. Attachment of human aortic smooth muscle cells (AoSMCs was similar to both materials. ePET/ePGA-d materials maybe a step towards bypass graft materials that can be custom-designed to promote cellular attachment while serving as a drug delivery platform for IH prevention.

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

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


    Tetramethyl-terephthalate (TMT) is the constitutive linker of the flexible porous iron(III) carboxylate Metal Organic Framework (MOF) MIL-88B_4CH₃ 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 μg ml⁻¹, respectively. The recovery of the TMT reached 86, 89 and 97% for urine, spleen and liver tissues, respectively. The linearity of the calibration curves in urine and tissues was satisfactory in all cases as evidenced by correlation coefficients >0.990. The within-day and between-day precisions were <15% (n=6) and the accuracy ranged in all cases between 86 and 103%. This method has finally allowed the quantification of TMT in rat urine and in tissue samples of rats administered intravenously with iron(III) tetramethyltherepthalate MIL-88B_4CH₃ nanoparticles.

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

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


    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.

  9. A brief review of para-xylene oxidation to terephthalic acid as a model of primary C-H bond activation

    Nor Aqilah Mohd Fadzil; Mohd Hasbi Ab Rahim; Gaanty Pragas Maniam


    The oxidation of para-xylene to terephthalic acid has been commercialised as the AMOCO process (Co/Mn/Br) that uses a homogeneous catalyst of cobalt and manganese together with a corrosive bromide compound as a promoter. This process is conducted in acidic medium at a high tempera-ture (175-225 °C). Concerns over environmental and safety issues have driven studies to find mild-er oxidation reactions of para-xylene. This review discussed past and current progress in the oxida-tion of para-xylene process. The discussion concentrates on the approach of green chemistry in-cluding (1) using heterogeneous catalysts with promising high selectivity and mild reaction condi-tion, (2) application of carbon dioxide as a co-oxidant, and (3) application of alternative promoters. The optimisation of para-xylene oxidation was also outlined.

  10. Toxicokinetics of terephthalic acid%对苯二甲酸的毒代动力学研究

    姚宏伟; 王心如; 王顶贤; 戴建国; 徐锡坤; 施爱民


    通过研究对苯二甲酸(TPA)在大鼠的毒代动力学,为制定生物接触限值(BEI)提供依据。选清洁级SD大鼠8只,一次性灌胃染毒100mg/kgBWTPA后,采用反相高效液相色谱法测定尿TPA浓度,用3P97计算毒代动力学参数。结果显示,TPA在体内的毒代动力学行为符合一级吸收二室模型,吸收速率常数ka为0.51/h,吸收相半衰期t1/2ka=0.488h,分布相半衰期t1/2d为2.446h,达峰时间tpeak为2.16h,消除速率常数Ku为0.143/h,消除相半衰期t1/2β为31.551h,TPA经尿排泄累积量为10.00mg,24h内约50%的TPA由尿排泄,48h内约52%,72h内约53%以上的TPA由尿排泄。结论:TPA在体内吸收快、消除快,主要以原形由尿排泄,提示职业人群的工后尿TPA可作为接触性生物标志物。%In order to study the toxicokinetics of terephthalic acid(TPA) inrats, and provide scientific basis for its biological exposed index(BEI), the concentrations of urine TPA in rats after single oral administration in dose of 100mg/kgBW were determined by high pressure liquid chromatography. The toxicokinetic parameters were computed by using 3P97 program. The results showed that the first-order kinetics and two-compartment model were noted on the elimination of TPA . The main toxicokinetic parameters were as follows: Ka=0.51/h, T1/2ka=0.488h, T1/2α=2.446h ,Tpeak =2.160h, Ku=0.143/h,T1/2β=31.551h, Xu(max)= 10.00mg. The excretion rates of TPA in urine were about 50%, 52% and 53% in 0~24h, 0~48h and 0~72 h respectively after administration. TPA is well absorbed when given orally and rapidly eliminated via urine. Urine TPA at the end of work shift should be considered as a biomarker of exposure for the occupational workers.

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

    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)


    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)

  12. The preparation of terephthalic acid by solvent-free oxidation of p-xylene with air over T(p-Cl)PPMnCl and Co(OAc)2

    Yang Xiao; Xiao Yan Zhang; Qin Bo Wang; Ze Tan; Can Cheng Guo; Wei Deng; Zhi Gang Liu; He Fei Zhang


    An attempt has been made to prepare terephthalic acid (TPA) by solvent-free oxidation of p-xylene (PX) with air over tetra(p-chlorophenylporphinato)manganese chloride (T(p-Cl)PPMnCl) and cobalt acetate. The co-catalysis between T(p-Cl)PPMnCl and Co(OAc)2 has been discovered under solvent-free conditions. TPA yield could be increased significantly when T(p-Cl)PPMnCl and Co(OAc)2 were used together. The addition of T(p-Cl)PPMnCl into the reaction mixture over Co(OAc)2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA. The effect of temperature on reaction was also investigated.

  13. 工业PTA氧化过程的多目标优化%Multi-objective Optimization of Industrial Purified Terephthalic Acid Oxidation Process

    牟盛静; 苏宏业; 古勇; 褚健


    Multi-objective optimization of a purified terephthalic acid (PTA) oxidation unit is carried out in this paper by using a process model that has been proved to describe industrial process quite well. The model is a semiempirical structured into two series ideal continuously stirred tank reactor (CSTR) models. The optimal objectives include maximizing the yield or inlet rate and minimizing the concentration of 4-carboxy-benzaldhyde, which is the main undesirable intermediate product in the reaction process. The multi-objective optimization algorithm applied in this study is non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ). The performance of NSGA-Ⅱ is further illustrated by application to the title process.

  14. Aldehyde-alcohol reactions catalyzed under mild conditions by chromium(III) terephthalate metal organic framework (MIL-101) and phosphotungstic acid composites.

    Bromberg, Lev; Hatton, T Alan


    Porous materials based on chromium(III) terephthalate metal organic frameworks (MIL-101) and their composites with phosphotungstic acid (PTA) were studied as heterogeneous acid catalysts in aldehyde-alcohol reactions exemplified by acetaldehyde-phenol (A-P) condensation and dimethylacetal formation from benzaldehyde and methanol (B-M reaction). The MIL-101 was synthesized solvothermically in water, and the MIL101/PTA composite materials were obtained by either impregnation of the already prepared MIL-101 porous matrix with phosphotungstic acid solution or by solvothermic treatment of aqueous mixtures of Cr(NO(3))(3), and terephthalic and phosphotungstic acids. The MIL101/PTA materials appeared to be effective catalysts for both A-P and B-M reactions occurring at room temperature, with half-lives ranging from 0.5 h (A-P) to 1.5-2 h (B-M) and turnover numbers over 600 for A-P and over 2900 for the B-M reaction, respectively. A synergistic effect of the strong acidic moieties (PTA) addition to mildly acidic Brønsted and Lewis acid cites of the MIL-101 was observed with the MIL101/PTA composites. The ability of the PTA and MIL101/PTA materials to strongly absorb and condense acetaldehyde vapors was discovered, with the MIL101/PTA absorbing over 10-fold its dry weight of acetaldehyde condensate at room temperature. The acetaldehyde was converted rapidly to crotonaldehyde and higher-molecular-weight compounds while in contact with MIL-101 and MIL101/PTA materials. The stability of the MIL-101 and MIL101/PTA catalysts was assessed within four cycles of the 1-day alcohol-aldehyde reactions in terms of the overall catalyst recovery, PTA or Cr content, and reaction rate constants in each cycle. The loss of the catalyst over 4 cycles was approximately 10 wt % for all tested catalysts due to the incomplete recovery and minute dissolution of the components. The reaction rates in all cycles remained unchanged and the catalyst losses stopped after the third cycle. The developed

  15. Synthesis of aminoaldonic acids

    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...... and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones......,4-lactone, respectively. A 2,3-aziridino-2,3-dideoxypentonamide 70 was also prepared from D-glucono-1,5-lactone. The lactones were converted into methyl 3,4-O-isopropylidene-2-O-sulfonyl esters 42, 50, 62 and 68, which upon treatment with concentrated aqueous ammonia yielded the aziridino compounds...

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

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


    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 to obtain carbamoyl and carboxylic acid functionalities over the thermodynamically most favored imide group. Products derived from both anhydrides 1 and 2 were isolated as pure regioisomeric compounds under innovative experimental conditions. The chemo- and regioselectivity of products derived from dianhydrides were determined by NMR spectroscopy and confirmed by density functional theory (DFT). All products were characterized by NMR, FTIR, and MS. PMID:24511299

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

    Adrián Ochoa-Terán


    Full Text Available 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 to obtain carbamoyl and carboxylic acid functionalities over the thermodynamically most favored imide group. Products derived from both anhydrides 1 and 2 were isolated as pure regioisomeric compounds under innovative experimental conditions. The chemo- and regioselectivity of products derived from dianhydrides were determined by NMR spectroscopy and confirmed by density functional theory (DFT. All products were characterized by NMR, FTIR, and MS.

  18. Non-dispersive solvent extraction of p-toluic acid from purified terephthalic acid plant wastewater with p-xylene as extractant

    Qing-ran KONG; You-wei CHENG; Li-jun WANG; Xi LI‡


    题目:对二甲苯非分散相溶剂萃取精对苯二甲酸工业废水中的对甲基苯甲酸  目的:采用对二甲苯为萃取剂,通过非分散相溶剂萃取(膜基萃取)同时回收利用精对苯二甲酸(PTA)工业废水中的对甲基苯甲酸和水。  创新点:1.采用非分散相溶剂萃取有效地实现了工业条件下 PTA 废水的净化和资源的回收利用;2.采用数学模拟优化工业萃取的操作参数。  方法:1.进行对二甲苯萃取实验,考察操作条件对萃取效率和萃余水杂质浓度的影响;2.通过数学模拟,建立膜萃取过程的数学模型,对操作参数与膜结构参数进行敏感性分析。  结论:1.非分散相溶剂萃取可以有效解决 PTA 工业废水的回收利用问题;2.质量传递的速率控制步骤是管程中的水相扩散;3.优化的工业操作条件为:中空纤维膜内径为200~250μm,萃取时间为50~60 s,水油两相体积比为9.0,萃取温度为318 K。%Non-dispersive solvent extraction (NDSE) with p-xylene as extractant was employed as a novel separation method to recover both p-toluic (PT) acid and water from purified terephthalic acid (PTA) wastewater. The mass transport behavior of PT acid from aqueous solution to p-xylene was investigated by experiments and numerical simulation. Experiments showed that NDSE is feasible and effective. Residual PT acid in the raffinate can be reduced to lower than the permitted limit of wastewater re-use (100 g/m3) with extraction time longer than 60 s in industrial conditions. A mathematical model of PT acid mass transport was developed to optimize the membrane module performance. The model was validated with the experimental results with relative errors of less than 6%. Numerical analysis for mass transfer through the lumen side, the porous membrane layer, and the shell side showed that PT acid transport in the aqueous solution is the rate determining step. The effects

  19. 降低精对苯二甲酸溶剂系统醋酸消耗的研究%Research and Implementation of Decreasing the Acetic Acid Consumption in Purified Terephthalic Acid Solvent System

    徐圆; 朱群雄


    Decreasing the acetic acid consumption in purified terephthalic acid(PTA) solvent system has become a hot issue with common concern.In accordance with the technical features.the electrical conductivity is in direct proportion to the acetic acid content.General regression neural network(GRNN)is used to establish the model of electrical conductivity on the basis of mechanism analysis,and then particle swarm optimization (PSO)algorithm with the improvement of mertia weight and population diversity is proposed to regulate the operatmg conditions.Thus.the method of decreasing the acid lossS is derived and applied to PTA solvent system in a chemical plant.Cases studies show that the precision of modeling and optimization are higher.The results also provide the optimal operating conditions,which decrease the cost and improve the profit.

  20. Diisononyl 1,2-cyclohexanedicarboxylic acid (DINCH) and Di(2-ethylhexyl) terephthalate (DEHT) in indoor dust samples: concentration and analytical problems.

    Nagorka, Regine; Conrad, André; Scheller, Christiane; Süssenbach, Bettina; Moriske, Heinz-Jörn


    Possible human health effects of phthalate plasticizers have been intensely discussed during the last decade. Di(2-ethylhexyl) phthalate (DEHP), the phthalate acid ester with the largest production volume worldwide, has been substituted by new compounds like Diisononyl 1,2-cyclohexanedicarboxylic acid (DINCH) or Di(2-ethylhexyl) terephthalate (DEHT) in many applications. There are numerous reports about concentration levels of phthalates in indoor environments, but data on concentrations of these alternative plasticizers are not available yet. Also, the methods for the determination of phthalate substitutes are not yet established. This study presents the results achieved by quantification using different analytical methods. Data on the concentration of DEHT and DINCH in 953 dust samples from German households are presented. These samples were obtained in four different studies conducted from 1997 to 2009. Maximum concentrations of 110 mg DINCH/kg dust and 440 mg DEHT/kg dust were found. Especially the amount of DINCH has increased significantly after the market introduction of this plasticizer in 2002. Up to the beginning of 2006, DINCH was found in 44% of the dust samples. Dust samples collected in 2009 indicate an increased concentration for both softeners.

  1. Heat Treatment Effects on the Mechanical Properties and Morphologies of Poly (Lactic Acid/Poly (Butylene Adipate-co-terephthalate Blends

    Hsien-Tang Chiu


    Full Text Available In this study the relationships between mechanicals properties and morphology of the poly (lactic acid (PLA/poly (butylene adipate-co-terephthalate (PBAT blends with or without heat treatment were investigated. The differential scanning calorimetry (DSC analysis showed that blends have a two-phase structure indicating that they are immiscible. On the other hand, the PLA/PBAT (30/70 blend achieved the best tensile and impact strength because of its sea-island morphology, except for high PBAT content. The PLA/PBAT (70/30 and PLA/PBAT (50/50 blends showed irregular and directive-layer morphologies, in scanning electron microscopy (SEM analysis, producing a break cross-section with various fiber shapes. Both blends showed lower tensile strength and impact strength than the PLA/PBAT (30/70. After heat treatment, the PLA/PBAT blends showed high modulus of tensile and HDT because of a high degree of crystallization. The high degree of crystallization in the blends, which originated in the heat treatment, reduced their impact strength and elongation. However, the effect of high degree of crystallization on the PLA/PBAT (30/70 blend was small because of its sea-island morphology.

  2. Radiation induced deposition of copper nanoparticles inside the nanochannels of poly(acrylic acid)-grafted poly(ethylene terephthalate) track-etched membranes

    Korolkov, Ilya V.; Güven, Olgun; Mashentseva, Anastassiya A.; Atıcı, Ayse Bakar; Gorin, Yevgeniy G.; Zdorovets, Maxim V.; Taltenov, Abzal A.


    Poly(ethylene terephthalate) PET, track-etched membranes (TeMs) with 400 nm average pore size were UV-grafted with poly(acrylic acid) (PAA) after oxidation of inner surfaces by H2O2/UV system. Carboxylate groups of grafted PAA chains were easily complexed with Cu2+ ions in aqueous solutions. These ions were converted into metallic copper nanoparticles (NPs) by radiation-induced reduction of copper ions in aqueous-alcohol solution by gamma rays in the dose range of 46-250 kGy. Copper ions chelating with -COOH groups of PAA chains grafted on PET TeMs form polymer-metal ion complex that prevent the formation of agglomerates during reduction of copper ions to metallic nanoparticles. The detailed analysis by X-Ray diffraction technique (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the deposition of copper nanoparticles with the average size of 70 nm on the inner surface of nanochannels of PET TeMs. Samples were also investigated by FTIR, ESR spectroscopies to follow copper ion reduction.

  3. Improving the simultaneous removal of chemical oxygen demand and terephthalic acid in a cross-flow aerobic sludge reactor by using response surface methodology.

    Hu, Dong-Xue; Tian, Yu; Chen, Zhao-Bo; Ge, Hui; Cui, Yu-Bo; Ran, Chun-Qiu


    Central composite design and response surface methodology (RSM) were implemented to optimize the operational parameters for a cross-flow aerobic sludge reactor (CFASR) in remedying mixed printing and dyeing wastewater (MPDW). The individual and interactive effects of three variables, hydraulic retention time (HRT), pH and sludge loading rate (SLR), on chemical oxygen demand (COD) and terephthalic acid (TA) removal rates were evaluated. For HRT of 15.3-19.8 hours, pH of 7.2-8.1 and SLR of 0.4-0.6 kg chemical oxygen demand (COD) per kg mixed liquor suspended solids per day, COD and TA removal rates of the CFASR exceeded 85% and 90%, respectively. The check experiment revealed that the effluent from the optimized CFASR was stable below the limitation of 100 mg COD/L and the TA concentration decreased by 6.0% compared to the usual CFASR. The results verified that the RSM was useful for optimizing the operation parameters of the CFASR in remedying MPDW.

  4. 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

    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)


    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)

  5. "Long-distance" H/D isotopic self-organization phenomena in scope of the infrared spectra of hydrogen-bonded terephthalic and phthalic acid crystals

    Flakus, Henryk T.; Hachuła, Barbara.; Hołaj-Krzak, Jakub T.; Al-Agel, Faisal A.; Rekik, Najeh


    This paper deals with the experimental and theoretical studies of abnormal properties of terephthalic acid (TAC) and phthalic acid (PAC) crystals manifested in the H/D isotopic exchange. The widely utilized deuteration routine appeared to be insufficiently effective in the case of the h6-TAC isotopomer. In the case of the d4-TAC derivative the isotopic exchange process occurred noticeably more effectively. In contrast, both isotopomers of PAC, h6 and d4, appeared much more susceptible for deuteration. A theoretical model was elaborated describing "long-distance" dynamical co-operative interactions involving hydrogen bonds in TAC and PAC crystals. The model assumes extremely strong dynamical co-operative interactions of hydrogen bonds from the adjacent (COOH)2 cycles. This leads to an additional stabilization of h6-TAC molecular chains. The interaction energies affect the chemical equilibrium of the H/D isotopic exchange. The model predicts a differentiated influence of the H and D atoms linked to the aromatic rings on to the process. In this approach the totally-symmetric Csbnd H bond stretching vibrations and the proton stretching totally symmetric vibrations couple with the π-electronic motions. It was also shown that identical hydrogen isotope atoms, H or D, in whole TAC molecules, noticeably enlarge the energy of the dynamical co-operative interactions in the crystals, in contrast to the case of different hydrogen isotopes present in the carboxyl groups and linked to the aromatic rings. The "long-distance" dynamical co-operative interactions in PAC crystals were found of a minor importance due to the electronic properties of PAC molecules.

  6. Simple synthesis of radiolabelled bromoacetic acid

    Abrams, D.N.; Gaudreault, R.C.; Noujaim, A.A.

    Bromoacetic acid has been used as a chemical precursor in the synthesis of a large number of biologically active compounds including uracil (1) and malonic acid. We required /sup 3/H and /sup 14/C labelled bromoacetic acid as an intermediate in the preparation of new bifunctional chelating agents for dual label studies with proteins and monoclonal antibodies. The sulfur catalyzed bromination of acetic acid proved to be a facile synthesis of radiolabelled bromoacetic acid directly from /sup 3/H and /sup 14/C sodium acetate.

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

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


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

  8. Synthesis of β-Amino Acid Derivatives

    Zhao Yonghua; Ma Zhihua; Jiang Nan; Wang Jianbo


    In recent years, β-amino acids and their derivatives have attracted considerable attention due to their occurrence in biologically active natural products, such as dolastatins,cyclohexylnorstatine and Taxol. β-Amino acids also find application in the synthesis of β-lactams,piperidines, indolizidines. Moreover, the peptides consisting of β-amino acids, the so-called β-peptides, have been extensively studied recently. Consequently, considerable efforts have been directed to the synthesis of β-amino acids and their derivatives1. In particular, stereoselective synthesis of β-amino acids has been a challenging project, and there are only limited methods available. In this presentation, we report our efforts in this area.


    Hui-qing Zhang; Xiong-yan Zhao; De-shan Liu; Qi-xiang Zhou


    A series of liquid crystalline multi-block copolymers poly[1,6-bis(4-oxybenzoyl-oxy)hexane terephthalate]-b-bisphenol A polycarbonate (PHTH-6-b-PC) with different segment lengths were synthesized in tetrachloroethane by solution polycondensation in which hydroxyl terminated PC and acyl chloride terminated PHTH-6 were used. It is found that block copolymers with high molecular weight and welldefined structures were obtained. All the block copolymers exhibit a nematic liquid crystalline texture.

  10. Synthesis and Structure of Tetraploid (Imidazole) Copper(Ⅱ) Terephthalate, [Cu (Im) 4](teph)

    万钧; 叶素娟; 温永红; 张书圣


    The crystal structure of [Cu(Im)4] (teph) ( Im= imidazole,teph = terephthalate) has been determined by X-ray crystallography. It crystallizes in the triclinic system, space group P1 with cell dimensions of a = 0.80356(16) nm, b = 0.84269(17)nm, c =0.88967(18)nm, α=76.90(3)°, β=68.95(3)°, γ=75.94(3)°, and Z =1. Its structure of the title compound is composed of discrete monomeric molecule of [Cu(Im)4](teph). The copper (II) ions have a square plane geometry with the CuN4 chromophore.

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

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


    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.

  12. Poly(ethylene Terephthalate), Pet: A Review On The Synthesis Processes, Degradation Mechanisms And Its Recycling [poli(tereftalato De Etileno), Pet:uma Revisão Sobre Os Processos De íntese, Mecanismos De Egradação E Sua Reciclagem

    Romao W.; Spinace M.A.S.; De Paoli M.-A.


    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 a...

  13. 工业PTA氧化过程中4-CBA浓度的模糊神经网络模型%Fuzzy Neural Network Model of 4-CBA Concentration for Industrial Purified Terephthalic Acid Oxidation Process

    刘瑞兰; 苏宏业; 牟盛静; 贾涛; 陈渭泉; 褚健


    A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeling.First, a set of preliminary input variables is selected according to prior knowledge and experience. Secondly, a method based on the maximum correlation coefficient is proposed to detect the dead time between the process variables and response variables. Finally, the fuzzy curve method is used to reduce the unimportant input variables. The simulation results based on industrial data show that the relative error range of the FNN model is narrower than that of the American Oil Company (AMOCO) model. Furthermore, the FNN model can predict the trend of the 4-CBA concentration more accurately.

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

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


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

  15. Lipase catalyzed synthesis of epoxy-fatty acids

    CHEN, Qian; LI, Zu-Yi


    Lipase catalyzed synthesis of epoxy-fatty acidas from unsaturated carboxylic acids was investigated.Under mild conditions unsaturated arboxylic acids were convcveed to peroxide,then the unsaturated peroxycarboxylic acids epoxidised the C=C bond of themselves

  16. The synthesis and some properties of nylon 4,T

    Gaymans, R.J.


    The synthesis of nylon 4,T from tetramethylenediamine and a terephthalic acid derivative was studied in a two step-process: prepolymerization, followed by postcondensation in the solid state (4 h, 290°C). The prepolymers were prepared by the nylon salt method, ester polymerization method, interfacia

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

    Millar, J.M.


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

  18. Synthesis of Two Natural Oleanolic Acid Saponins

    LI, Chun-Xia; ZANG, Jing; WANG, Peng; ZHANG, Xiu-Li; GUAN, Hua-Shi; LI, Ying-Xia


    Ocean University of China, Qingdao, Shandong 266003, China3-O-[β-D-Glucopyranosyl-(1→3)-α-L-arabinopyranosyl]-oleanolic acid-28-O-[β-D-glucopyranosyl] ester 1 was synthesized concisely by a convergent strategy. Using stepwise fashion for the synthesis of saponin 2,3-O-{ [β-D-glucopyranosyl-( 1→ 2 ) ]-[ α-L-arabinopyranosyl-( 1→ 3 ) ]-α-L-arabinopyranosyl }-oleanolic acid-28-O-(β-D-glucopyranosyl) ester, an abnormal phenomenon, that the terminal arabinosyl residue took the 1C4 conformation instead of typical 4C1 form, was observed. Deprotection or heating could not resume the normal conformation,which resulted in the product of 2' not 2.

  19. Synthesis of lipoteichoic acids in Bacillus anthracis.

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


    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. Polyglycerol phosphate-specific monoclonal antibodies were used to detect LTA in the envelope of B. anthracis strain Sterne (pXO1(+) pXO2(-)) vegetative forms. B. anthracis mutants lacking ltaS1, ltaS2, ltaS3, or ltaS4 did not display defects in growth or LTA synthesis. In contrast, B. anthracis strains lacking both ltaS1 and ltaS2 were unable to synthesize LTA and exhibited reduced viability, altered envelope morphology, aberrant separation of vegetative forms, and decreased sporulation efficiency. Expression of ltaS1 or ltaS2 alone in B. anthracis as well as in other microbes was sufficient for polyglycerol phosphate synthesis. Thus, similar to S. aureus, B. anthracis employs LtaS enzymes to synthesize LTA, an envelope component that promotes bacterial growth and cell division.

  20. Synthesis of 6E-Geranylgeraniol-19-oic Acid

    LI Shu-hua; PENG Li-Zeng; LI Wei-dong; LI Yu-lin


    The present paper deals with the facile synthesis of 6E-geranylgeraniol-19-oic acid(1), a naturally occuring alicyclic diterpene acid, by a Horner-Wadsworth-Emmons olefination of two readily available fragments 7 and 3.

  1. Synthesis of Stereoisomers of 3-Aminocyclohexanecarboxylic Acid and cis-3-Aminocyclohexene-5-carboxylic Acid

    HU Yu; YU Sheng-Liang; YANG Yu-Jin; ZHU Jin; DENG Jin-Gen


    A practical synthesis of stereoisomers of 3-aminocyclohexanecarboxylic acid and cis-3-aminocyclohexene-5-carboxylic acid was achieved from cyclohexene-4-carboxylic acid via a key resolving approach with chiral 1-phenylethylamine.

  2. Deoxyribonucleic acid synthesis and deoxynucleotide metabolism during bacterial spore germination.

    Setlow, P


    Deoxyribonucleic acid (DNA) synthesis during germination of Bacillus megaterium spores takes place in two stages. In stage I (0-55 min) DNA synthesis is slow and there is no detectable net synthesis, whereas in stage II (from 55 min on) the rate of synthesis is much faster and net DNA synthesis occurs. Deoxyribonucleotide pool sizes match the rates of DNA synthesis in stages I and II. The level of deoxyribonucleotide triphosphates is not correlated with the level of deoxyribonucleotide kinases, but rather with that of ribonucleotide reductase activity.

  3. Synthesis of Biobased Succinonitrile from Glutamic Acid and Glutamine

    Lammens, T.M.; Nôtre, Le J.; Franssen, M.C.R.; Scott, E.L.; Sanders, J.P.M.


    Succinonitrile is the precursor of 1,4-diaminobutane, which is used for the industrial production of polyamides. This paper describes the synthesis of biobased succinonitrile from glutamic acid and glutamine, amino acids that are abundantly present in many plant proteins. Synthesis of the intermedia

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

    Forster, Denis; DeKleva, Thomas W.


    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)

  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

    Jutakan Boonmee


    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. The use of layer by layer self-assembled coatings of hyaluronic acid and cationized gelatin to improve the biocompatibility of poly(ethylene terephthalate) artificial ligaments for reconstruction of the anterior cruciate ligament.

    Li, Hong; Chen, Chen; Zhang, Shurong; Jiang, Jia; Tao, Hongyue; Xu, Jialing; Sun, Jianguo; Zhong, Wei; Chen, Shiyi


    In this study layer by layer (LBL) self-assembled coatings of hyaluronic acid (HA) and cationized gelatin (CG) were used to modify polyethylene terephthalate (PET) artificial ligament grafts. Changes in the surface properties were characterized by scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and contact angle and biomechanical measurements. The cell compatibility of this HA-CG coating was investigated in vitro on PET films seeded with human foreskin dermal fibroblasts over 7days. The results of our in vitro studies demonstrated that the HA-CG coating significantly enhanced cell adhesion, facilitated cell growth, and suppressed the expression of inflammation-related genes relative to a pure PET graft. Furthermore, rabbit and porcine anterior cruciate ligament reconstruction models were used to evaluate the effect of this LBL coating in vivo. The animal experiment results proved that this LBL coating significantly inhibited inflammatory cell infiltration and promoted new ligament tissue regeneration among the graft fibers. In addition, the formation of type I collagen in the HA-CG coating group was much higher than in the control group. Based on these results we conclude that PET grafts coated with HA-CG have considerable potential as substitutes for ligament reconstruction.

  7. Au3+/Au0 Supported on Chromium(III Terephthalate Metal Organic Framework (MIL-101 as an Efficient Heterogeneous Catalystfor Three-Component Coupling Synthesis of Propargylamines

    Lili Liu


    Full Text Available Post-synthesis modification is a useful method for the functionalization of metal–organic frameworks (MOFs. A novel catalyst Au@MIL-101-ED-SA (ED = ethylenediamine, SA = salicylaldehyde, containing coexisting Au3+ ions and Au0 nanoparticles, was prepared successfully by post-synthesis modification with ethylenediamine, salicylaldehyde and gold. Gold nanoparticles supported on MIL-101 (Au@MIL-101 were prepared successfully by the impregnation method. Au@MIL-101-ED-SA and Au@MIL-101 were characterized by N2 adsorption–desorption, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and inductively coupled plasma-optical emission spectrometry. Au@MIL-101-ED-SA and Au@MIL-101 were applied as environmentally friendly catalysts in the three-component coupling reaction of aldehydes, amines, and alkynes for the preparation of diverse propargylamines. Au@MIL-101-ED-SA contained a fraction of cationic gold (Au3+/Au0 = 0.9 and showed higher catalytic activity than Au@MIL-101, which was prepared by the impregnation method. Furthermore, the reactions were performed under heterogeneous conditions and the novel catalyst was successfully recycled for four consecutive runs.

  8. 厌氧折流板反应器处理PTA废水及其相分离特性%Terephthalic acid(PTA) wastewater treated by anaerobic baffled reactor and its phase separation characteristics

    杨忠林; 钟中; 韩萍芳; 吕效平


    The start-up and phase separation characteristics of the anaerobic baffled reactor (ABR) treating purified terephthalic acid (PTA) wastewater were investigated. Results showed that under these conditions the temperature was (35 ± 1) ℃ , hydraulic retention time was 40 h and volumetric loading rate was 3.60 kg/(m3·d) , the ABR started up successfully and the maximum removal efficiency of COD reached 80% after 62 d operation. The concentration of volatile fatty acids ( VFA) in the different compartments of ABR decreased along the flow direction, In contrast, the content of CH4 , the volatile suspended solid (VSS) , the ratio of VSS and the total suspended solid (TSS) , the specific methane production activities and the coenzyme F420 increased, the significant phase separation characteristics.%对厌氧折流板反应器(ABR)处理精对苯二甲酸(PTA)生产废水的启动及相分离过程进行研究.结果表明:经过62 d的运行,反应器在(35±1)℃、水力停留时间40 h、容积负荷3.60 kg/(m3·d)的条件下,最大COD去除率达到80%以上,ABR启动成功.沿着水流方向,不同格室中挥发性脂肪酸(VFA)浓度依次减小,CH4含量不断增加,且污泥中挥发性悬浮固体浓度(VSS)及其与总悬浮固体浓度(TSS)之比、产甲烷活性和辅酶F420不断增大,ABR中显示出显著的厌氧微生物相分离特性.

  9. Effect of Hydroxyapatite Nanoparticles on the Degradability of Random Poly(butylene terephthalate-co-aliphatic dicarboxylates Having a High Content of Terephthalic Units

    Nina Heidarzadeh


    Full Text Available Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The second synthesis step was a thermal transesterification between the corresponding homopolymers, always attaining a random distribution as verified by NMR spectroscopy. Hybrid polymer composites containing 2.5 wt % of hydroxyapatite (HAp were also prepared by in situ polymerization. Hydroxyl groups on the nanoparticle surface allowed the grafting of polymer chains in such a way that composites were mostly insoluble in the typical solvents of the parent copolyesters. HAp had some influence on crystallization from the melt, thermal stability, and mechanical properties. HAp also improved the biocompatibility of samples due to the presence of Ca2+ cations and the damping effect of phosphate groups. Interestingly, HAp resulted in a significant increase in the hydrophilicity of samples, which considerably affected both enzymatic and hydrolytic degradability. Slight differences were also found in the function of the dicarboxylic component, as the lowest degradation rates was found for the sample constituted of the most hydrophobic sebacic acid units.

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

    Chian-Hui Lai


    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.

  11. Study on Cell Cycle Regulatory Mechanism in Rat Bladder Carcinogenesis Promoted by Terephthalic Acid%对苯二甲酸促进大鼠膀胱癌发生的细胞周期调节机制研究

    石远; 唐建梅


    [ Objective ] To study the cell cycle regulatory mechanism in rat bladder carcinogenesis promoted by terephthalic acid (TPA). [ Methods ] A total of 50 male Wister rats were divided into test group (30 rats) and control group (20 rats), respectively intraperitoneally injected with N-methyl-N-nitrosourea (MNU) and citrate buffer twice a week for 4 weeks, and then basal diet containing 5%TPA were given to the test group and basal diet to the control group separately for the next 22 weeks. Major regulatory proteins in Gl cell cycle checkpoint including pl6INK4a, cyclin-dependent kinase 4 (Cdk4), cyclin Dl, and retinoblastoma protein (pRb) were determined during various stages of urinary bladder carcinogenesis by immunohistochemistry. [ Results ] In MNU-5% TPA treated group, the incidences of overexpression of Cdk4, cyclin Dl and pRb in papilloma were significantly higher than those in epithelial simple hyperplasia (P=0.023, .P<0.001 and P< 0.001, respectively) and in papillary or nodular (PN) hyperplasia (P=0.042, ^=0.012 and P=0.002, respectively). The incidence of absent expression of pl61NK4 in papilloma was much higher than that in epithelial simple hyperplasia {P=0.004) and in PN hyperplasia (P=0.02). [ Conclusion ] Our results clearly reveal that the disorder of pl6INK4-cyclin Dl/Cdk4-pRb pathway is associated with bladder carcinogenesis promoted by TPA-stone.%[目的]研究对苯二甲酸(terephthalic acid,TPA)促进膀胱癌发生的细胞周期调节机制.[方法]50只blister大鼠分为实验组(30只)及对照组(20只),每周两次分别腹腔注射甲基亚硝墓脲(MNU)和冰柠檬酸盐缓冲液,持续4周.在随后的22周,分别给大鼠饲以含5%TPA和0%TPA的饲料.利用免疫组织化学方法检查G1细胞周期关卡的主要调节蛋白包括抑癌基因p16(INK4a)蛋白(pl6(INK4a))、周期素依赖性蛋白激酶4(Cdk4)、细胞周期蛋白D1(cyclin Dl)和成视网膜细胞瘤蛋白(pRb)在大鼠膀胱癌发生各

  12. Inadequacy of prebiotic synthesis as origin of proteinous amino acids.

    Wong, J T; Bronskill, P M


    The production of some nonproteinous, and lack of production of other proteinous, amino acids in model prebiotic synthesis, along with the instability of glutamine and asparagine, suggest that not all of the 20 present day proteinous amino acids gained entry into proteins directly from the primordial soup. Instead, a process of active co-evolution of the genetic code and its constituent amino acids would have to precede the final selection of these proteinous amono acids.

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

    Weber, Arthur L.


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

  14. Polymeric cracking of waste polyethylene terephthalate to chemicals and energy.

    Brems, Anke; Baeyens, Jan; Vandecasteele, Carlo; Dewil, Raf


    Polyethylene terephthalate (PET) is a widely used thermoplastic. PET residues represent on average 7.6 wt% of the different polymer wastes in Europe. Pyrolysis of these wastes is attracting increasing interest, and PET is a potential candidate for this thermal process. The paper measures and discusses the kinetics of the pyrolysis reaction in terms of the reaction rate constants as determined by dynamic thermogravimetric analysis, with special emphasis on the required heating rate to obtain relevant results. The product yields and compositions are also determined. Gaseous products represent 16-18 wt%. The amounts of condensables and carbonaceous residue are a function of the operating mode, with slow pyrolysis producing up to 24 wt% of carbonaceous residue. Major condensable components are benzoic acid, monovinyl terephthalate, divinyl terephthalate, vinyl benzoate, and benzene. The present paper complements previous literature findings by (1) the study of the influence of the heating rate on the reaction kinetics in dynamic pyrolysis tests, (2) the isothermal investigation in a fluidized bed reactor to pyrolyze PET, and (3) the assessment of upgrading and recovery of the products. The paper concludes with a proposed reactor recommendation for PET pyrolysis, in either the bubbling or circulating fluidized bed operating mode.

  15. Synthesis of fatty acid starch esters in supercritical carbon dioxide

    Muljana, Henky; van der Knoop, Sjoerd; Keijzer, Danielle; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.


    This manuscript describes an exploratory study on the synthesis of fatty acid/potato starch esters using supercritical carbon dioxide (scCO(2)) as the solvent. The effects of process variables such as pressure (6-25 MPa), temperature (120-150 degrees C) and various basic catalysts and fatty acid der

  16. Concise synthesis of a novel antifungal agent 4-methoxydecanoic acid

    Pagudala Narsimha


    Full Text Available 4-Methoxy decanoic acid is belongs to a fatty acid family and has a novel anti- fungal activity. The aliphatic molecule has been synthesized in seven steps with an overall yield 41%. The synthesis was started from a commercially available epichloro hydrin and all the reactions were very clean.

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

    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:


    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)

  18. Transesterification of Ethylene Carbonate with Dimethyl Terephthalate over Various Metal Acetate Catalysts


    The reaction between ethylene carbonate and dimethyl terephthalate was carried out for the simultaneous synthesis of dimethyl carbonate and poly( ethylene terephthalate). This reaction is an excellent chemical process that is environmentally friendly and produces no poisonous substance. The metal acetate catalysts used for this reaction are discussed in detail. Lithium acetate dihydrate was found to be a novel and efficient catalyst for this reaction. Compared with other metal acetates, lithium acetate dihydrate can attain a maximum catalytic activity at a lower concentration.When the reaction was carried out under the following conditions: the reaction temperature from 230 to 250 ℃, molar ratio of ethylene carbonate(EC) to dimethyl terephthalate(DMT) 3: 1, reaction time 3 h, and a catalyst amount of 0. 4% (molar fraction to DMT), the yield of dimethyl carbonate(DMC) was 79. 1%.

  19. Phosphoric Acid-Mediated Synthesis of Vinyl Sulfones through Decarboxylative Coupling Reactions of Sodium Sulfinates with Phenylpropiolic Acids.

    Rong, Guangwei; Mao, Jincheng; Yan, Hong; Zheng, Yang; Zhang, Guoqi


    A novel phosphoric acid -mediated synthesis of vinyl sulfones through decarboxylative coupling reactions of sodium sulfinates with phenylpropiolic acids is described. This transformation is efficient and environmentally friendly.

  20. Synthesis of L-2-amino-8-oxodecanoic acid: an amino acid component of apicidins

    Linares de la Morena, María Lourdes; Agejas Chicharro, Francisco Javier; Alajarín Ferrández, Ramón; Vaquero López, Juan José; Álvarez-Builla Gómez, Julio


    The synthesis Of L-2-amino-8-oxodecanoic acid (Aoda) is described. This is a rare amino acid component of apicidins, a family of new cyclic tetrapeptides, inhibitors of histone deacetylase. Aoda was synthesised in seven steps from L-glutamic acid along with some derivatives. Universidad de Alcalá Fundación General de la Universidad de Alcalá FEDER

  1. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

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


    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order...

  2. Palmitic acid and linoleic acid metabolism in Caco-2 cells: Different triglyceride synthesis and lipoprotein secretion

    van Greevenbroek, M.M.J.; Voorhout, W.F.; Erkelens, D.W.; van Meer, G.; de Bruin, T.W.A.


    Polarized monolayers of intestinal Caco-2 cells were used to study the effects of saturated palmitic acid (16:0) and polyunsaturated linoleic acid (18:2) on triglyceride synthesis and lipoprotein secretion. Monolayers were incubated for 24 h, at the apical or lumenal side, with palmitic acid (16:0)

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

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


    Degradation of unusual fatty acids through β-oxidation within transgenic plants has long been hypothesized as a major factor limiting the production of industrially useful unusual fatty acids in seed oils. Arabidopsis seeds expressing the castor fatty acid hydroxylase accumulate hydroxylated fatty acids up to 17% of total fatty acids in seed triacylglycerols; however, total seed oil is also reduced up to 50%. Investigations into the cause of the reduced oil phenotype through in vivo [(14)C]acetate and [(3)H]2O metabolic labeling of developing seeds surprisingly revealed that the rate of de novo fatty acid synthesis within the transgenic seeds was approximately half that of control seeds. RNAseq analysis indicated no changes in expression of fatty acid synthesis genes in hydroxylase-expressing plants. However, differential [(14)C]acetate and [(14)C]malonate metabolic labeling of hydroxylase-expressing seeds indicated the in vivo acetyl-CoA carboxylase activity was reduced to approximately half that of control seeds. Therefore, the reduction of oil content in the transgenic seeds is consistent with reduced de novo fatty acid synthesis in the plastid rather than fatty acid degradation. Intriguingly, the coexpression of triacylglycerol synthesis isozymes from castor along with the fatty acid hydroxylase alleviated the reduced acetyl-CoA carboxylase activity, restored the rate of fatty acid synthesis, and the accumulation of seed oil was substantially recovered. Together these results suggest a previously unidentified mechanism that detects inefficient utilization of unusual fatty acids within the endoplasmic reticulum and activates an endogenous pathway for posttranslational reduction of fatty acid synthesis within the plastid.

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

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


    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.

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

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele


    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

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

    Morowitz, Harold; Peterson, Eta; Chang, Sherwood


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

  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

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


    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. Differential diagnosis in patients with suspected bile acid synthesis defects

    Dorothea Haas; Hongying Gan-Schreier; Claus-Dieter Langhans; Tilman Rohrer; Guido Engelmann; Maura Heverin; David W Russell


    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.

  9. Biobased synthesis of acrylonitrile from glutamic acid

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


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

  10. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao


    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  11. Synthesis of triamino acid building blocks with different lipophilicities.

    Jyotirmoy Maity

    Full Text Available To obtain different amino acids with varying lipophilicity and that can carry up to three positive charges we have developed a number of new triamino acid building blocks. One set of building blocks was achieved by aminoethyl extension, via reductive amination, of the side chain of ortnithine, diaminopropanoic and diaminobutanoic acid. A second set of triamino acids with the aminoethyl extension having hydrocarbon side chains was synthesized from diaminobutanoic acid. The aldehydes needed for the extension by reductive amination were synthesized from the corresponding Fmoc-L-2-amino fatty acids in two steps. Reductive amination of these compounds with Boc-L-Dab-OH gave the C4-C8 alkyl-branched triamino acids. All triamino acids were subsequently Boc-protected at the formed secondary amine to make the monomers appropriate for the N-terminus position when performing Fmoc-based solid-phase peptide synthesis.

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

    Mijin Dušan Ž.


    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.

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


    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...

  14. Green Synthesis of Acid Esters from Furfural via Stobbe Condensation

    Shubhra Banerjee


    Full Text Available Solvent-free Stobbe condensation of furfural 1 with dimethyl succinate 2 under anhydrous conditions at room temperature using dry-solid potassium tertiary butoxide gave 3-carbomethoxy, 4-furyl-3-butenoic acid 3, which upon methylation followed by Stobbe condensation reaction with different aldehydes and/or ketones under anhydrous conditions at room temperature afforded substituted carbomethoxy acids 5a–f. These acid ester products were saponified to the corresponding dicarboxylic acids 6a–f which are useful in the synthesis of photochromic fulgides.

  15. Synthesis of p-(Di-n-propylsulphamyl Benzoic Acid

    S. K. Shukla


    Full Text Available A process for the synthesis of p-carboxybenzene sulphonylchloride by oxidation of toluene-p-sulphonylchloride as well as toluene-p-sulphonic acid has been developed. p-carboxybenzene sulphonylchloride on condensation with di-n-propylamine yield p-(di-n-propylsulphamyl -benzoic acid, an uricusuric agent employed in chronic gouty arthritis and used as an antiuric adjuvant known in trade as "Benemid, Probenecid".

  16. Methane-to-acetic acid synthesis matriculates at Penn State

    Rotman, D.


    Direct conversion of methane to commercially valuable chemicals remains one of the grails of industrial chemistry. But scientists at Pennsylvania State University (University Park) appear to have made a significant step forward, reporting the direct catalytic conversion of methane into acetic acid under relatively mild conditions. Commercial acetic production involves a three-step process, including steam reforming of methane to synthesis gas (syngas) and the carbonylation of methanol of acetic acid.

  17. Stereoselective synthesis of unsaturated α-amino acids.

    Fanelli, Roberto; Jeanne-Julien, Louis; René, Adeline; Martinez, Jean; Cavelier, Florine


    Stereoselective synthesis of unsaturated α-amino acids was performed by asymmetric alkylation. Two methods were investigated and their enantiomeric excess measured and compared. The first route consisted of an enantioselective approach induced by the Corey-Lygo catalyst under chiral phase transfer conditions while the second one involved the hydroxypinanone chiral auxiliary, both implicating Schiff bases as substrate. In all cases, the use of a prochiral Schiff base gave higher enantiomeric excess and yield in the final desired amino acid.

  18. Design and Synthesis of Novel Peptide Nucleic Acid Monomers

    白金泉; 李英; 刘克良


    All of the four nucleobases in DNA have replaced the 4-hydroxy group of N-[2-(tert-butoxycarbonylaminomethyl)-trams-4-hydroxy]tetrahydropyrrole acetic acid methyl ester with cis-stereochemistry. An efficient route for the synthesis of N-[2-(tert-butoxycarbonylaminomethyl)-trans-4-hydroxy]-tetrahydropyrrole acetic acid methyl ester has been developed.Starting with this intermediate, the protected monmers were synthesized by the Mitsunobu reaction or via its tosylate.

  19. Cyclic phosphatidic acid and lysophosphatidic acid induce hyaluronic acid synthesis via CREB transcription factor regulation in human skin fibroblasts.

    Maeda-Sano, Katsura; Gotoh, Mari; Morohoshi, Toshiro; Someya, Takao; Murofushi, Hiromu; Murakami-Murofushi, Kimiko


    Cyclic phosphatidic acid (cPA) is a naturally occurring phospholipid mediator and an analog of the growth factor-like phospholipid lysophosphatidic acid (LPA). cPA has a unique cyclic phosphate ring at the sn-2 and sn-3 positions of its glycerol backbone. We showed before that a metabolically stabilized cPA derivative, 2-carba-cPA, relieved osteoarthritis pathogenesis in vivo and induced hyaluronic acid synthesis in human osteoarthritis synoviocytes in vitro. This study focused on hyaluronic acid synthesis in human fibroblasts, which retain moisture and maintain health in the dermis. We investigated the effects of cPA and LPA on hyaluronic acid synthesis in human fibroblasts (NB1RGB cells). Using particle exclusion and enzyme-linked immunosorbent assays, we found that both cPA and LPA dose-dependently induced hyaluronic acid synthesis. We revealed that the expression of hyaluronan synthase 2 messenger RNA and protein is up-regulated by cPA and LPA treatment time dependently. We then characterized the signaling pathways up-regulating hyaluronic acid synthesis mediated by cPA and LPA in NB1RGB cells. Pharmacological inhibition and reporter gene assays revealed that the activation of the LPA receptor LPAR1, Gi/o protein, phosphatidylinositol-3 kinase (PI3K), extracellular-signal-regulated kinase (ERK), and cyclic adenosine monophosphate response element-binding protein (CREB) but not nuclear factor κB induced hyaluronic acid synthesis by the treatment with cPA and LPA in NB1RGB cells. These results demonstrate for the first time that cPA and LPA induce hyaluronic acid synthesis in human skin fibroblasts mainly through the activation of LPAR1-Gi/o followed by the PI3K, ERK, and CREB signaling pathway.

  20. Kynurenic acid synthesis by human glioma

    Vezzani, A; Gramsbergen, J B; Versari, P;


    Biopsy material from human gliomas obtained during neurosurgery was used to investigate whether pathological human brain tissue is capable of producing kynurenic acid (KYNA), a natural brain metabolite which can act as an antagonist at excitatory amino acid receptors. Upon in vitro exposure to 40...

  1. Succinic Acid Synthesis by Ethanol-Grown Yeasts

    Svetlana V. Kamzolova


    Full Text Available The synthesis of succinic acid in ethanol-containing media has been tested in 32 yeasts of different genera (Debaryomyces, Candida, Pichia, Saccharomyces, Torulopsis. The capability of succinic acid synthesis was revealed in 29 strains, from which two most effective producers were selected. When grown in a fermentor under high aeration in mineral medium with pulsed addition of ethanol, the strain Candida catenulata VKM Y-5 produced succinic acid up to 5.2 g/L with mass yield of 32.6 % and energy yield of 14.8 %; the other strain, Candida zeylanoides VKM Y-2324, excreted 9.4 g/L of succinic acid with mass and energy yields of 39 and 17.8 %, respectively. It was indicated that succinic acid formation in the yeasts was accompanied by the synthesis of considerable amounts of malic acid, which was apparently due to a high activity of the glyoxylate cycle. Growth characteristics of both strains were studied in dependence on the concentrations of ethanol, zinc ions and nitrogen in the medium.

  2. One-Pot Synthesis of N-Phosphoryl Amino Acids

    GUO Xin; FU Hua; LIN Chang-Xue; ZHAO Yu-Fen


    @@ Phosphoramidates have been considered as an important class of rationally designed therapeutics especially asoligonucleotide analogs employed as antisene and antigene agents. [1] N-Phosphoryl amino acids are of biological andpharmaceutical interest, [2] and can be used as the building blocks in synthesis of polypeptides. [3

  3. Synthesis of gold nanoparticles using various amino acids.

    Maruyama, Tatsuo; Fujimoto, Yuhei; Maekawa, Tetsuya


    Gold nanoparticles (4-7nm) were synthesized from tetraauric acid using various amino acids as reducing and capping agents. The gold nanoparticles were produced from the incubation of a AuCl4(-) solution with an amino acid at 80°C for 20min. Among the twenty amino acids tested, several amino acids produced gold nanoparticles. The color of the nanoparticle solutions varied with the amino acids used for the reduction. We adopted l-histidine as a reducing agent and investigated the effects of the synthesis conditions on the gold nanoparticles. The His and AuCl4(-) concentrations affected the size of the gold nanoparticles and their aggregates. The pH of the reaction solution also affected the reaction yields and the shape of the gold nanoparticles.

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

    Akiyoshi Hoshino


    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.

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

    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)


    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.

  6. [Possible route for thiamine participation in fatty acid synthesis].

    Buko, V U; Larin, F S


    The possibility of thiamine partaking in the synthesis of fatty acids through the functions unrelated to the catalytic properties of thiamine-diphosphate was studied. Rats kept on a fat-free ration devoid of thiamine were given thiamine of thiochrome with no vitaminic properties. The total fatty acids content in different tissues and incorporation therein of tagged acetate and pyruvate was determined, while the fatty acids composition of the liver was investigated by using gas chromatography. Thiamine and thiochrome produced a similar effect on a number of the study factors, i.e. they forced down the total acids level in the spleen, intensified incorporation of tagged acetate and pyruvate in fatty acids of the heart and uniformly changed the fatty acids composition in the liver. It is suggested that the unindirectional effects of thiamine and thiochrome is due to the oxidative transformation of thiamine into thiochrome.

  7. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu


    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues.

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

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


    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.

  9. 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

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


    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.

  10. Synthesis of isothiocyanate-derived mercapturic acids

    Vermeulen, M.; Zwanenburg, B.; Chittenden, G.J.F.; Verhagen, H.


    Twelve mercapturic acids derived from saturated and unsaturated aliphatic and aromatic isothiocyanates were synthesised, by adding isothiocyanate to a solution of N-acetyl-L-cysteine and sodium bicarbonate, in a typical yield of 77%. Isothiocyanates were synthesised first by adding the corresponding

  11. Fatty acid phytyl ester synthesis in chloroplasts of Arabidopsis.

    Lippold, Felix; vom Dorp, Katharina; Abraham, Marion; Hölzl, Georg; Wewer, Vera; Yilmaz, Jenny Lindberg; Lager, Ida; Montandon, Cyrille; Besagni, Céline; Kessler, Felix; Stymne, Sten; Dörmann, Peter


    During stress or senescence, thylakoid membranes in chloroplasts are disintegrated, and chlorophyll and galactolipid are broken down, resulting in the accumulation of toxic intermediates, i.e., tetrapyrroles, free phytol, and free fatty acids. Chlorophyll degradation has been studied in detail, but the catabolic pathways for phytol and fatty acids remain unclear. A large proportion of phytol and fatty acids is converted into fatty acid phytyl esters and triacylglycerol during stress or senescence in chloroplasts. We isolated two genes (PHYTYL ESTER SYNTHASE1 [PES1] and PES2) of the esterase/lipase/thioesterase family of acyltransferases from Arabidopsis thaliana that are involved in fatty acid phytyl ester synthesis in chloroplasts. The two proteins are highly expressed during senescence and nitrogen deprivation. Heterologous expression in yeast revealed that PES1 and PES2 have phytyl ester synthesis and diacylglycerol acyltransferase activities. The enzymes show broad substrate specificities and can employ acyl-CoAs, acyl carrier proteins, and galactolipids as acyl donors. Double mutant plants (pes1 pes2) grow normally but show reduced phytyl ester and triacylglycerol accumulation. These results demonstrate that PES1 and PES2 are involved in the deposition of free phytol and free fatty acids in the form of phytyl esters in chloroplasts, a process involved in maintaining the integrity of the photosynthetic membrane during abiotic stress and senescence.

  12. Synthesis of Chiral Amino Cyclic Phosphoric Acids


    Chirai amino cyclic phosphoric acids, 5-amino-2-hydroxy-4- (4-nitrophenyl)-l, 3,2-dioxaphospho- rinane 2-oxide and 2-hydroxy-4- (4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64. 2% and 72. 8% respectively) from 2-amino-l-aryl-l,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.

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

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


    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.

  14. Reaction kinetics of polybutylene terephthalate polycondensation reaction

    Darda, P. J.; Hogendoorn, J. A.; Versteeg, G. F.; Souren, F.


    The kinetics of the forward polycondensation reaction of polybutylene terephthalate (PBT) has been investigated using thermogravimetric analysis (TGA). PBT - prepolymer with an initial degree of polymerization of 5.5 was used as starting material. The PBT prepolymer was prepared from dimethyl tereph

  15. Inhibition of in vitro cholesterol synthesis by fatty acids.

    Kuroda, M; Endo, A


    Inhibitory effect of 44 species of fatty acids on cholesterol synthesis has been examined with a rat liver enzyme system. In the case of saturated fatty acids, the inhibitory activity increased with chain length to a maximum at 11 to 14 carbons, after which activity decreased rapidly. The inhibition increased with the degree of unsaturation of fatty acids. Introduction of a hydroxy group at the alpha-position of fatty acids abolished the inhibition, while the inhibition was enhanced by the presence of a hydroxy group located in an intermediate position of the chain. Branched chain fatty acids having a methyl group at the terminal showed much higher activity than the corresponding saturated straight chain fatty acids with the same number of carbons. With respect to the mechanism for inhibition, tridecanoate was found to inhibit acetoacetyl-CoA thiolase specifically without affecting the other reaction steps in the cholesterol synthetic pathway. The highly unsaturated fatty acids, arachidonate and linoleate, were specific inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA synthase. On the other hand, ricinoleate (hydroxy acid) and phytanate (branched-chain acid) diminished the conversion of mevalonate to sterols by inhibiting a step or steps between squalene and lanosterol.

  16. Microwave-Assisted Rapid Enzymatic Synthesis of Nucleic Acids.

    Hari Das, Rakha; Ahirwar, Rajesh; Kumar, Saroj; Nahar, Pradip


    Herein we report microwave-induced enhancement of the reactions catalyzed by Escherichia coli DNA polymerase I and avian myeloblastosis virus-reverse transcriptase. The reactions induced by microwaves result in a highly selective synthesis of nucleic acids in 10-50 seconds. In contrast, same reactions failed to give desired reaction products when carried out in the same time periods, but without microwave irradiation. Each of the reactions was carried out for different duration of microwave exposure time to find the optimum reaction time. The products produced by the respective enzyme upon microwave irradiation of the reaction mixtures were identical to that produced by the conventional procedures. As the microwave-assisted reactions are rapid, microwave could be a useful alternative to the conventional and time consuming procedures of enzymatic synthesis of nucleic acids.

  17. Synthesis of ellagic acid and its 4,4'-di-Ο-alky derivatives from gallic acid

    Alam, Ashraful; 高口, 豊; 坪井, 貞夫


    Synthesis of ellagic acid and its 4,4'-di-Ο-alkyl derivatives from gallic acid is described. Ellagic acid is prepared by oxidative coupling of gallic acid with ο-chloranil. Functionalized methyl bormogallate underwent Ullmann coupling to give the biphenyl that upon lactonization resulted in the ellagic acid and its alkoxy derivatives.

  18. Tannic acid-mediated green synthesis of antibacterial silver nanoparticles.

    Kim, Tae Yoon; Cha, Song-Hyun; Cho, Seonho; Park, Youmie


    The search for novel antibacterial agents is necessary to combat microbial resistance to current antibiotics. Silver nanoparticles (AgNPs) have been reported to be effective antibacterial agents. Tannic acid is a polyphenol compound from plants with antioxidant and antibacterial activities. In this report, AgNPs were prepared from silver ions by tannic acid-mediated green synthesis (TA-AgNPs). The reaction process was facile and involved mixing both silver ions and tannic acid. The absorbance at 423 nm in the UV-Visible spectra demonstrated that tannic acid underwent a reduction reaction to produce TA-AgNPs from silver ions. The synthetic yield of TA-AgNPs was 90.5% based on inductively coupled plasma mass spectrometry analysis. High-resolution transmission electron microscopy and atomic force microscopy images indicated that spherical-shaped TA-AgNPs with a mean particle size of 27.7-46.7 nm were obtained. Powder high-resolution X-ray diffraction analysis indicated that the TA-AgNP structure was face-centered cubic with a zeta potential of -27.56 mV. The hydroxyl functional groups of tannic acid contributed to the synthesis of TA-AgNPs, which was confirmed by Fourier transform infrared spectroscopy. The in vitro antibacterial activity was measured using the minimum inhibitory concentration (MIC) method. The TA-AgNPs were more effective against Gram-negative bacteria than Gram-positive bacteria. The MIC for the TA-AgNPs in all of the tested strains was in a silver concentration range of 6.74-13.48 μg/mL. The tannic acid-mediated synthesis of AgNPs afforded biocompatible nanocomposites for antibacterial applications.

  19. A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

    Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L


    The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

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

    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))


    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.

  1. Facile Synthesis of Oleanolic Acid Monoglycosides and Diglycosides

    Mao-Sheng Cheng


    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.

  2. Synthesis of Rosin Acid Starch Catalyzed by Lipase

    Rihui Lin


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

  3. Very long chain fatty acid synthesis in sunflower kernels.

    Salas, Joaquín J; Martínez-Force, Enrique; Garcés, Rafael


    Most common seed oils contain small amounts of very long chain fatty acids (VLCFAs), the main components of oils from species such as Brassica napus or Lunnaria annua. These fatty acids are synthesized from acyl-CoA precursors in the endoplasmic reticulum through the activity of a dissociated enzyme complex known as fatty acid elongase. We studied the synthesis of the arachidic, behenic, and lignoceric VLCFAs in sunflower kernels, in which they account for 1-3% of the saturated fatty acids. These VLCFAs are synthesized from 18:0-CoA by membrane-bound fatty acid elongases, and their biosynthesis is mainly dependent on NADPH equivalents. Two condensing enzymes appear to be responsible for the synthesis of VLCFAs in sunflower kernels, beta-ketoacyl-CoA synthase-I (KCS-I) and beta-ketoacyl-CoA synthase-II (KCS-II). Both of these enzymes were resolved by ion exchange chromatography and display different substrate specificities. While KCS-I displays a preference for 20:0-CoA, 18:0-CoA was more efficiently elongated by KCS-II. Both enzymes have different sensitivities to pH and Triton X-100, and their kinetic properties indicate that both are strongly inhibited by the presence of their substrates. In light of these results, the VLCFA composition of sunflower oil is considered in relation to that in other commercially exploited oils.

  4. 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

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


    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)

  5. pH and ionic strength-sensitive drug release from poly (L-lysine-alt-terephthalic acid) microcapsules: effects of dissociable groups on the microcapsule structure; pH to ion kyodo ni otoshita poly(L-lysine-alt-terephthal san) microcapsule kara no yakubutsu hoshutsu seigyo

    Makino, K. [Science University of Tokyo, Tokyo (Japan). Faculty of Pharmaceutical Science


    Poly(L-lysine-alt-terephthalic acid) microcapsules change their particle size, volume and the membrane permeability, depending on pH and the ionic strength. The mechanisms of the change in membrane shape were studied. The water content in the membrane and the sensitivity to the stimuli changed corresponding to the changes in the charge density and in the hydrophobicity of the membrane. These phenomena were considered as the phase transition of a hydrogen. In aqueous solutions, the microcapsules shrank by the addition of multi-valent cations or by the addition of the solvent with low permittivity such as ethanol. The viscosity of the membrane was high when the water content of the microcapsules was high. Also, the mass density of the membrane was inversely proportional to the microcapsule size. 4 refs., 3 figs.

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

    Kristina Vlahoviček-Kahlina


    Full Text Available Muramic acid is found in many peptide natural products containing oligo(polysaccharide 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-fluorenylmethyloxycarbonyl-α-D-glucopyranoside (6 from N-acetylglucosamine (1 is described. Important improvements over previous synthetic approaches to glucopyranosides 2 (benzyl 2-acetamido-2-deoxy-α-D-glucopyranoside and 3 (benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-D-glucopyranoside, key building blocks in preparation of 6, include synthesis simplification and efficient isolation and purification. Optically pure (S-2-chloropropionic acid 7 was prepared and introduced to the positon 3-O of sugar moiety to give compound 4 (benzyl 2-acetamido-4,6-O-benzylidene-3-O-[(R-1-carboxyethyl]-2-deoxy-α-D-glucopyranoside with the (R-configuration of the lactyl side-chain in excellent overall yield and optical purity. Deacetylation of amino group gave compound 5 (benzyl 2-amino-4,6-O-benzylidene-3-O-[(R-1-carboxyethyl]-2-deoxy-α-D-glucopyranoside suitable for incorporation of the Fmoc protecting group to give protected muramic acid derivative 6, a useful building block in peptide synthesis.

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

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


    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.

  8. Induction of phytic acid synthesis by abscisic acid in suspension-cultured cells of rice.

    Matsuno, Koya; Fujimura, Tatsuhito


    A pathway of phytic acid (PA) synthesis in plants has been revealed via investigations of low phytic acid mutants. However, the regulation of this pathway is not well understood because it is difficult to control the environments of cells in the seeds, where PA is mainly synthesized. We modified a rice suspension culture system in order to study the regulation of PA synthesis. Rice cells cultured with abscisic acid (ABA) accumulate PA at higher levels than cells cultured without ABA, and PA accumulation levels increase with ABA concentration. On the other hand, higher concentrations of sucrose or inorganic phosphorus do not affect PA accumulation. Mutations in the genes RINO1, OsMIK, OsIPK1 and OsLPA1 have each been reported to confer low phytic acid phenotypes in seeds. Each of these genes is upregulated in cells cultured with ABA. OsITPK4 and OsITPK6 are upregulated in cells cultured with ABA and in developing seeds. These results suggest that the regulation of PA synthesis is similar between developing seeds and cells in this suspension culture system. This system will be a powerful tool for elucidating the regulation of PA synthesis.

  9. 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

    Mallinger, A


    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.

  10. Synthesis and Characterization of Fatty Acid Conjugates of Niacin and Salicylic Acid.

    Vu, Chi B; Bemis, Jean E; Benson, Ericka; Bista, Pradeep; Carney, David; Fahrner, Richard; Lee, Diana; Liu, Feng; Lonkar, Pallavi; Milne, Jill C; Nichols, Andrew J; Picarella, Dominic; Shoelson, Adam; Smith, Jesse; Ting, Amal; Wensley, Allison; Yeager, Maisy; Zimmer, Michael; Jirousek, Michael R


    This report describes the synthesis and preliminary biological characterization of novel fatty acid niacin conjugates and fatty acid salicylate conjugates. These molecular entities were created by covalently linking two bioactive molecules, either niacin or salicylic acid, to an omega-3 fatty acid. This methodology allows the simultaneous intracellular delivery of two bioactives in order to elicit a pharmacological response that could not be replicated by administering the bioactives individually or in combination. The fatty acid niacin conjugate 5 has been shown to be an inhibitor of the sterol regulatory element binding protein (SREBP), a key regulator of cholesterol metabolism proteins such as PCSK9, HMG-CoA reductase, ATP citrate lyase, and NPC1L1. On the other hand, the fatty acid salicylate conjugate 11 has been shown to have a unique anti-inflammatory profile based on its ability to modulate the NF-κB pathway through the intracellular release of the two bioactives.

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

    Markus Heiny


    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.

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

    Mamani, J.B., E-mail: [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)


    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.

  13. Transcutaneous delivery of levodopa: enhancement by fatty acid synthesis inhibition.

    Babita, Kumar; Tiwary, Ashok K


    The present investigation aimed at evaluating the role of fatty acid synthesis inhibition in enhancing transcutaneous delivery of levodopa (LD). Rat epidermis was treated with ethanol and various doses of cerulenin (an inhibitor of fatty acid synthase enzyme system) for reducing the normal level of fatty acids. Calcium chloride (0.1 mM) and/or verapamil (1 microM) were coapplied to cerulenin treated skin in order to modulate duration of epidermal perturbation. These treated skin portions were used for estimation of altered triglyceride content (an indicator of fatty acid synthesis), differential scanning calorimetry (DSC) analysis, and in vitro permeation of LD. Plasma concentration of LD was monitored in rats following topical application of various transdermal formulations. Application of cerulenin (0.1 or 0.15 mM/7 cm(2)) to viable rat skin inhibited approximately 60% triglyceride synthesis with respect to control at 2 h. Coapplication of calcium chloride (0.1 mM) significantly increased this inhibition, whereas verapamil application reduced this effect. The decrease in triglyceride content reduced the enthalpy of the lipid endothermic transition. The in vitro permeation of LD was enhanced 3-fold across skin excised after treatment with cerulenin. LD did not permeate across normal skin. The effective plasma concentration (C(eff)) of LD was achieved within 3 h and maintained till 10 h by a single topical application of a carbidopa-levodopa combination (1:4) to ethanol-perturbed cerulenin-treated skin. Coapplication of calcium chloride reduced the time lag to achieve C(eff) to 2 h and maintained it till 24 h. A single transdermal LD (64 mg) patch formulated with calcium chloride (0.1 mM) and cerulenin (0.1 mM) dissolved in a propylene glycol:ethanol (7:3) mixture seems to offer a noninvasive approach for transcutaneous delivery of levodopa.

  14. Synthesis of zincosilicate mordenite using citric acid as complexing agent

    MeiDong; JianjuoWang; YuhanSun


    The zincosilicate analog of zeolite mordenite was hydrothermally synthesized in the presence of citric acid and characterized with several spectroscopic techniques.The zeolite thus prepared had a higher crystallinity and Zn concentration in the framework compared with the one obtained in the absence of citric acid.XRD and FTIR provided evidence for the incorporation of Zn in the framework.Results of XAFS indicated a tetrahedral structure of Zn in the lattice framework with a Zn-O distancd of 0.1938nm.It is speculated that the citric acid might decrease the concentration of Zn2 in the synthesis mixture,there by preventing the unfavorable-formation of oxide or hydroxide species.2001 Elsevier Science B.V.All rights reserved.

  15. 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

    M. Onciu


    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.

  16. Synthesis of benzyl cinnamate by enzymatic esterification of cinnamic acid.

    Wang, Yun; Zhang, Dong-Hao; Chen, Na; Zhi, Gao-Ying


    In this study, lipase catalysis was successfully applied in synthesis of benzyl cinnamate through esterification of cinnamic acid with benzyl alcohol. Lipozyme TLIM was found to be more efficient for catalyzing this reaction than Novozym 435. In order to increase the yield of benzyl cinnamate, several media, including acetone, trichloromethane, methylbenzene, and isooctane, were used in this reaction. The reaction showed a high yield using isooctane as medium. Furthermore, the effects of several parameters such as water activity, reaction temperature, etc, on this reaction were analyzed. It was pointed out that too much benzyl alcohol would inhibit lipase activity. Under the optimum conditions, lipase-catalyzed synthesis of benzyl cinnamate gave a maximum yield of 97.3%. Besides, reusable experiment of enzyme demonstrated that Lipozyme TLIM retained 63% of its initial activity after three cycles. These results were of general interest for developing industrial processes for the preparation of benzyl cinnamate.

  17. Depolymerization of polyethylene terephthalate in supercritical methanol

    Goto, Motonobu; Koyamoto, Hiroshi; Kodama, Akio; Hirose, Tsutomu; Nagaoka, Shoji


    The degradation of polyethylene terephthalate (PET) in supercritical methanol was investigated with the aim of developing a process for chemical recycling of waste plastics. A batch reactor was used at temperatures of 573-623 K under an estimated pressure of 20 MPa for a reaction time of 2-120 min. PET was decomposed to its monomers, dimethyl terephthalate and ethylene glycol, by methanolysis in supercritical methanol. The reaction products were analysed using size-exclusion chromatography, gas chromatography-mass spectrometry, and reversed-phase liquid chromatography. The molecular weight distribution of the products was obtained as a function of reaction time. The yields of monomer components of the decomposition products including by-products were measured. Continuous kinetics analysis was performed on the experimental data.

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

    Vasiljeva, I.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation)]. E-mail:; 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)


    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)

  19. (-)-Hydroxycitric Acid Nourishes Protein Synthesis via Altering Metabolic Directions of Amino Acids in Male Rats.

    Han, Ningning; Li, Longlong; Peng, Mengling; Ma, Haitian


    (-)-Hydroxycitric acid (HCA), a major active ingredient of Garcinia Cambogia extracts, had shown to suppress body weight gain and fat accumulation in animals and humans. While, the underlying mechanism of (-)-HCA has not fully understood. Thus, this study was aimed to investigate the effects of long-term supplement with (-)-HCA on body weight gain and variances of amino acid content in rats. Results showed that (-)-HCA treatment reduced body weight gain and increased feed conversion ratio in rats. The content of hepatic glycogen, muscle glycogen, and serum T4 , T3 , insulin, and Leptin were increased in (-)-HCA treatment groups. Protein content in liver and muscle were significantly increased in (-)-HCA treatment groups. Amino acid profile analysis indicated that most of amino acid contents in serum and liver, especially aromatic amino acid and branched amino acid, were higher in (-)-HCA treatment groups. However, most of the amino acid contents in muscle, especially aromatic amino acid and branched amino acid, were reduced in (-)-HCA treatment groups. These results indicated that (-)-HCA treatment could reduce body weight gain through promoting energy expenditure via regulation of thyroid hormone levels. In addition, (-)-HCA treatment could promote protein synthesis by altering the metabolic directions of amino acids. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Synthesis of a Nitro Analogue of Plakoric Acid

    ZHANG,Qi; JIN,Hong-Xia; LIU,He-Hua; WU,Yi-Kang


    Synthesis of a nitro analogue of plakoric acid is presented. The peroxy bond was incorporated into the substrate structure through a boron trifluoride etherate catalyzed methoxy-hydroperoxy group partial exchange reaction in djethyl ether with urea-hydrogen peroxide complex (UHP, a commercially available solid reagent) as the source of the hydrogen peroxide. Under the given conditions, only one of the two methoxyl groups underwent the MeO-OOH exchange and the resulting hydroperoxy hemiketal proceeded directly to the end product through an intramolecular Michael addition of the hydroperoxyl group to the nitro group activated carbon-carbon double bond.

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

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


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

  2. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Kitadai, Norio


    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.

  3. Route to Renewable PET: Reaction Pathways and Energetics of Diels–Alder and Dehydrative Aromatization Reactions Between Ethylene and Biomass-Derived Furans Catalyzed by Lewis Acid Molecular Sieves


    Silica molecular sieves that have the zeolite beta topology and contain framework Lewis acid centers (e.g., Zr-β, Sn-β) are useful catalysts in the Diels–Alder and dehydrative aromatization reactions between ethylene and various renewable furans for the production of biobased terephthalic acid precursors. Here, the main side products in the synthesis of methyl 4-(methoxymethyl)benzene carboxylate that are obtained by reacting ethylene with methyl 5-(methoxymethyl)-furan-2-carboxylate are iden...

  4. Lactic acid demineralization of shrimp shell and chitosan synthesis

    Alewo Opuada AMEH


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

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

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


    A complementary dopant system formed by hydrochloric and camphor sulfonic (CSA) acids was used in the in-situ synthesis of a polyaniline (PANi)/polyvinyl alcohol (PVA) composite. The conductivity measurements showed that the use of CSA either as single dopant or codopant caused a decrement up to 2 orders of magnitude on the overall conductivity as well as an improvement on thermal stability. The PANi/PVA composites were characterized by spectroscopic and thermal analysis. Conducting emeraldin...

  6. Synthesis of 6-phosphofructose aspartic acid and some related Amadori compounds.

    Hansen, Alexandar L; Behrman, Edward J


    We describe the synthesis and characterization of 6-phosphofructose-aspartic acid, an intermediate in the metabolism of fructose-asparagine by Salmonella. We also report improved syntheses of fructose-asparagine itself and of fructose-aspartic acid.

  7. Synthesis and characterization of acetic acid and ethanoic acid (based)-maleimide

    Poad, Siti Nashwa Mohd; Hassan, Nurul Izzaty; Hassan, Nur Hasyareeda


    A new route to the synthesis of maleimide is described. 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)acetic acid maleimide (1) and 2-(4-(2,5-Dioxo-2,5-dihydro- 1H-pyrrol-1-yl)phenyl)ethanoic acid maleimide (2) have been synthesized by the reaction of maleic anhydride with glycine and 4-aminophenyl acetic aicd. Maleimide (1) was synthesized by conventional technique while maleimide (2) was synthesized by microwave method. The compounds were characterized using FT-Infrared (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopies and Mass Spectrometry.

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

    Tonali eBlanco Ayala


    Full Text Available Kynurenic acid (KYNA, an astrocyte-derived, endogenous antagonist of α7 nicotinic acetylcholine and excitatory amino acid receptors, regulates glutamatergic, GABAergic, cholinergic and dopaminergic neurotransmission in several regions of the rodent brain. Synthesis of KYNA in the brain and elsewhere is generally attributed to the enzymatic conversion of L-kynurenine (L-KYN by kynurenine aminotransferases (KATs. However, alternative routes, including KYNA formation from D-kynurenine (D-KYN by D-amino acid oxidase (DAAO and the direct transformation of kynurenine to KYNA by reactive oxygen species (ROS, have been demonstrated in the rat brain. Using the rat cerebellum, a region of low KAT activity and high DAAO activity, the present experiments were designed to examine KYNA production from L-KYN or D-KYN by KAT and DAAO, respectively, and to investigate the effect of ROS on KYNA synthesis. In chemical combinatorial systems, both L-KYN and D-KYN interacted directly with peroxynitrite (ONOO- and hydroxyl radicals (OH•, resulting in the formation of KYNA. In tissue homogenates, the non-specific KAT inhibitor aminooxyacetic acid (AOAA; 1 mM reduced KYNA production from L-KYN and D-KYN by 85.1 ± 1.7% and 27.1 ± 4.5%, respectively. Addition of DAAO inhibitors (benzoic acid, kojic acid or 3-methylpyrazole-5-carboxylic acid; 5 µM each attenuated KYNA formation from L-KYN and D-KYN by ~35% and ~66%, respectively. ONOO- (25 µM potentiated KYNA production from both L-KYN and D-KYN, and these effects were reduced by DAAO inhibition. AOAA attenuated KYNA production from L-KYN + ONOO- but not from D-KYN + ONOO-. In vivo, extracellular KYNA levels increased rapidly after perfusion of ONOO- and, more prominently, after subsequent perfusion with L-KYN or D-KYN (100 µM. Taken together, these results suggest that different mechanisms are involved in KYNA production in the rat cerebellum, and that, specifically, DAAO and ROS can function as alternative routes

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

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


    Kynurenic acid (KYNA), an astrocyte-derived, endogenous antagonist of α7 nicotinic acetylcholine and excitatory amino acid receptors, regulates glutamatergic, GABAergic, cholinergic and dopaminergic neurotransmission in several regions of the rodent brain. Synthesis of KYNA in the brain and elsewhere is generally attributed to the enzymatic conversion of L-kynurenine (L-KYN) by kynurenine aminotransferases (KATs). However, alternative routes, including KYNA formation from D-kynurenine (D-KYN) by D-amino acid oxidase (DAAO) and the direct transformation of kynurenine to KYNA by reactive oxygen species (ROS), have been demonstrated in the rat brain. Using the rat cerebellum, a region of low KAT activity and high DAAO activity, the present experiments were designed to examine KYNA production from L-KYN or D-KYN by KAT and DAAO, respectively, and to investigate the effect of ROS on KYNA synthesis. In chemical combinatorial systems, both L-KYN and D-KYN interacted directly with peroxynitrite (ONOO−) and hydroxyl radicals (OH•), resulting in the formation of KYNA. In tissue homogenates, the non-specific KAT inhibitor aminooxyacetic acid (AOAA; 1 mM) reduced KYNA production from L-KYN and D-KYN by 85.1 ± 1.7% and 27.1 ± 4.5%, respectively. Addition of DAAO inhibitors (benzoic acid, kojic acid or 3-methylpyrazole-5-carboxylic acid; 5 μM each) attenuated KYNA formation from L-KYN and D-KYN by ~35% and ~66%, respectively. ONOO− (25 μM) potentiated KYNA production from both L-KYN and D-KYN, and these effects were reduced by DAAO inhibition. AOAA attenuated KYNA production from L-KYN + ONOO− but not from D-KYN + ONOO−. In vivo, extracellular KYNA levels increased rapidly after perfusion of ONOO− and, more prominently, after subsequent perfusion with L-KYN or D-KYN (100 μM). Taken together, these results suggest that different mechanisms are involved in KYNA production in the rat cerebellum, and that, specifically, DAAO and ROS can function as alternative

  10. Lewis Acidic Ionic Liquids As New Addition Catalyst For Oleic Acid To Monoestolide Synthesis

    Nadia Farhana Adnan


    Full Text Available Estolide compound has a large potential in many industrial applications such as biodegradable lubricants and in cosmetic formulation. In this study, monoestolide can be prepared by addition reaction of oleic acid under vacuum-reflux and solvent free condition for 10 hours at 85 °C in the presence of solid zinc chloride anhydrous (ZnCl2, choline chloride (ChCl and ionic liquids (IL ChCl-ZnCl2, ChCl-FeCl3, ChCl-SnCl2, ChCl-CuCl2 as homogenous acid catalysts. These reactions were compared with common homogenous catalyst namely sulfuric acid (H2SO4. The FTIR analysis show that addition reaction using the above catalysts showed the presence of three new peaks at 1732 cm-1 for C=O ester, 967.0 cm-1 for trans-CH=CH and 1176 cm-1 for C-O-C which confirmed the existence of monoestolide. The LC-MS results showed peak for the present of new monoestolides at retention time (tR 12.3 min corresponding to m/z 563.48. Among the IL, ChCl-ZnCl2 surprisingly exhibited higher activity which is 98 % acid oleic conversion and 80 % selective for the synthesis of monoestolides. As a result, this IL gave two potential functions as a solvent as well as a green catalyst for monoestolide synthesis from oleic acid.

  11. Recent developments in the catalytic asymmetric synthesis of alpha- and beta-amino acids.

    Ma, Jun-An


    The stereoselective synthesis of amino acids is of great importance for the construction of optically active natural products and pharmaceuticals. Apart from enzymes, a broad repertoire of chiral reagents, auxiliaries, and catalysts can be used for the formation of amino acids. Asymmetric reactions using catalytic amounts of chiral molecules provide efficient methods for the generation of optically active proteinogenic and nonproteinogenic amino acids. This minireview collects recent work on catalytic asymmetric synthesis of alpha- and beta-amino acids.

  12. Lipase catalyzed synthesis of organic acid esters of lactic acid in non-aqueous media.

    Kiran, K R; Divakar, S


    Lipases from Rhizomucor miehei (Lipozyme IM20) and porcine pancreas (PPL) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. Reactions were carried out at both shake-flask and bench-scale levels. Various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer pH and water volume, were investigated for optimization of yields. While ethylmethyl ketone (EMK) was found to be the best solvent for shake-flask reactions, chloroform gave higher yields at bench-scale level. Detailed studies were carried out with respect to the synthesis of palmitoyl and stearoyl lactic acids. At shake-flask level, maximum yields of 37.5 and 40% were observed in case of palmitoyl and stearoyl lactic acids, respectively, with Lipozyme IM20; at bench-scale level, the maximum yields were 85.1 and 99% respectively, when PPL was employed. Of all the organic acids employed (C(2)--C(18)), only lauric, palmitic and stearic acids gave yields above 50%. At bench-scale level, PPL could be reused for up to three cycles with yields above 40%. Esters prepared were found to conform to Food Chemical Codex (FCC) specifications in terms of acid value, ester value, sodium and lactic acid contents.

  13. Synthesis of long-chain polyunsaturated fatty acids in preterm newborns fed formula with long-chain polyunsaturated fatty acids

    Carnielli, Virgilio P.; Simonato, Manuela; Verlato, Giovanna; Luijendijk, Ingrid; De Curtis, Mario; Sauer, Pieter J. J.; Cogo, Paola E.


    Background: Docosahexaenoic acid (DHA) and arachidonic acid (AA) are long-chain polyunsaturated fatty acids (LCPs) that play pivotal roles in growth and neurodevelopment. Objective: We aimed to quantify the synthesis of LCPs in preterm infants fed infant formula containing LCPs. Design: Twenty-two p

  14. 对苯二甲酸催化加氢制备1,4-环己烷二甲酸的热力学分析%Thermodynamic Analysis of Catalytic Hydrogenation of Terephthalic Acid to 1,4-Cyclohexane-Dicarboxylic Acid

    朱庆才; 畅延青


    The thermodynamics of the hydrogenation of terephthalic acid(TA) to 1,4-cyclohexanedicarboxylic acid(CHDA) was studied,and the standard molar enthalpies of formation,standard molar enthalpies of vaporization and molar heat capacities at constant pressure of the main products and byproducts were calculated by the Constantinou-Gani group contribution method and Rozicka-Domalski group contribution method. The enthalpy changes,Gibbs free energy changes and equilibrium constants of the chemical reaction in the hydrogenation in the temperature range of 373.15-573.15 K were calculated also. The results showed that the benzene ring hydrogenation and decarboxylation were dominant in the hydrogenation of TA. The TA hydrogenation to CHDA is an exothermic reaction and low temperature is favorable toit,while the TA decarboxylation to benzoic acid is an endothermic reaction and high temperature is favorable to it. As low temperature is unbeneficial to the dissolution of TA,the appropriate reaction temperature should be chosen between 493.15-523.15 K.%采用Constantinou-Gani基团贡献法和Rozicka-Domalski基团贡献法计算了对苯二甲酸(TA)加氢制备1,4-环己烷二甲酸(CHDA)过程中可能涉及的主副产物的标准摩尔生成焓、标准摩尔蒸发焓和定压热容。在373.15~573.15 K的温度下,分别计算了TA加氢反应体系中各反应的焓变、Gibbs自由能变和平衡常数。计算结果表明,在373.15~573.15 K温度范围内,TA加氢反应以苯环加氢反应和脱羧基反应为主。TA加氢生成CHDA的反应是放热反应,低温有利于该反应的进行,而TA脱羧基生成苯甲酸的反应是吸热反应,高温有利于该反应的进行。但因低温不利于TA的溶解,综合考虑,选择TA加氢制备CHDA的反应温度为493.15~523.15 K较适宜。

  15. The effect of linoleic acid on the whole body synthesis rates of polyunsaturated fatty acids from α-linolenic acid and linoleic acid in free-living rats.

    Domenichiello, Anthony F; Kitson, Alex P; Chen, Chuck T; Trépanier, Marc-Olivier; Stavro, P Mark; Bazinet, Richard P


    Docosahexaenoic acid (DHA) is thought to be important for brain function. The main dietary source of DHA is fish, however, DHA can also be synthesized from precursor omega-3 polyunsaturated fatty acids (n-3 PUFA), the most abundantly consumed being α-linolenic acid (ALA). The enzymes required to synthesize DHA from ALA are also used to synthesize longer chain omega-6 (n-6) PUFA from linoleic acid (LNA). The large increase in LNA consumption that has occurred over the last century has led to concern that LNA and other n-6 PUFA outcompete n-3 PUFA for enzymes involved in DHA synthesis, and therefore, decrease overall DHA synthesis. To assess this, rats were fed diets containing LNA at 53 (high LNA diet), 11 (medium LNA diet) or 1.5% (low LNA diet) of the fatty acids with ALA being constant across all diets (approximately 4% of the fatty acids). Rats were maintained on these diets from weaning for 8 weeks, at which point they were subjected to a steady-state infusion of labeled ALA and LNA to measure DHA and arachidonic acid (ARA) synthesis rates. DHA and ARA synthesis rates were generally highest in rats fed the medium and high LNA diets, while the plasma half-life of DHA was longer in rats fed the low LNA diet. Therefore, increasing dietary LNA, in rats, did not impair DHA synthesis; however, low dietary LNA led to a decrease in DHA synthesis with tissue concentrations of DHA possibly being maintained by a longer DHA half-life.

  16. Baker's Yeast Deficient in Storage Lipid Synthesis Uses cis-Vaccenic Acid to Reduce Unsaturated Fatty Acid Toxicity.

    Sec, Peter; Garaiova, Martina; Gajdos, Peter; Certik, Milan; Griac, Peter; Hapala, Ivan; Holic, Roman


    The role of cis-vaccenic acid (18:1n-7) in the reduction of unsaturated fatty acids toxicity was investigated in baker's yeast Saccharomyces cerevisiae. The quadruple mutant (QM, dga1Δ lro1Δ are1Δ are2Δ) deficient in enzymes responsible for triacylglycerol and steryl ester synthesis has been previously shown to be highly sensitive to exogenous unsaturated fatty acids. We have found that cis-vaccenic acid accumulated during cultivation in the QM cells but not in the corresponding wild type strain. This accumulation was accompanied by a reduction in palmitoleic acid (16:1n-7) content in the QM cells that is consistent with the proposed formation of cis-vaccenic acid by elongation of palmitoleic acid. Fatty acid analysis of individual lipid classes from the QM strain revealed that cis-vaccenic acid was highly enriched in the free fatty acid pool. Furthermore, production of cis-vaccenic acid was arrested if the mechanism of fatty acids release to the medium was activated. We also showed that exogenous cis-vaccenic acid did not affect viability of the QM strain at concentrations toxic for palmitoleic or oleic acids. Moreover, addition of cis-vaccenic acid to the growth medium provided partial protection against the lipotoxic effects of exogenous oleic acid. Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.

  17. Methanolysis of Poly(ethylene terephthalate) in Supercritical Phase


    The depolymerization of poly(ethylene terephthalate, PET) in supercritical methanol is studied using a stainless stirred autoclave at temperature of 255~260℃, pressure of 8.5~14.0 MPa, and methanol/PET weight ratio of 3~8. Under the optimal conditions, the PET is depolymerized completely to its monomers in 60 min. The main products of the reaction are dimethyl terephthalate and ethylene glycol. There are still some small amounts of byproducts, such as methyl-(2-hydroxyethyl) terephthalate, bis(hydroxyethyl) terephthalate, dimers and oligomers. Reversed-phase high performance liquid chrom- atography and gas chromatography are used to analyze solid products and liquid products respectively. The results of depolymerization show that the yield of dimethyl terephthalate and the degree of PET depolymerization are dependent on the reaction temperature, weight ratio of methanol to PET and reaction time. But the reaction pressure has little influence on the depolymerization as long as methanol is in supercritical state.

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

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


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

  19. Polyethylene terephthalate thin films; a luminescence study

    Carmona-Téllez, S.; Alarcón-Flores, G.; Meza-Rocha, A.; Zaleta-Alejandre, E.; Aguilar-Futis, M.; Murrieta S, H.; Falcony, C.


    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.

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

    Lei Anping


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

  1. Total synthesis of five lipoteichoic acids of Clostridium difficile

    Hogendorf, Wouter Frederik Johan; Gisch, Nicolas; Schwudke, Dominik;


    The emergence of hypervirulent resistant strains have made Clostridium difficile a notorious nosocomial pathogen and has resulted in a renewed interest in preventive strategies, such as vaccines based on (synthetic) cell wall antigens. Recently, the structure of the lipoteichoic acid (LTA......) of this species has been elucidated. Additionally, this LTA was found to induce the formation of protective antibodies against C. difficile in rabbits and mice. The LTA from C. difficile is isolated as a microheterogenous mixture, differing in size and composition, impeding any structure-activity relationship...... studies. To ensure reliable biological results, pure and well-defined synthetic samples are required. In this work the total synthesis of LTAs from C. difficile with defined chain length is described and the initial biological results are presented....

  2. Electrochemical Synthesis of Dendritic Polyaniline in BrФnsted Acid Ionic Liquids

    刘宝友; 许丹倩; 徐振元


    BrФnsted acid ionic liquids were successfully applied to the electrochemical synthesis of polyaniline films on platinum electrode surfaces by using cyclic voltammetry. The scanning electron micrographs showed distinct changes in morphological structures. The films exhibited quite dense packing and good ordering of polymer dendrite as compared with those prepared using conventional hydrochloric acid, indicating that Bronsting acid ionic liquids might be promising alternatives to dual medium-dopants in the synthesis of conducting polymers.

  3. Enzymatic synthesis and application of fatty acid ascorbyl esters

    Stojanović Marija M.


    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

  4. Synthesis and photochromic property of nanosized amino acid polyoxometalate compounds

    Sun, Dehui; Zhang, Jilin; Ren, Huijuan; Cui, Zhenfeng


    A series of novel nanosized amino acid-polyoxometalate compounds were successfully synthesized using a low temperature solid-state chemical reaction method. Their compositions, structures, morphologies, photochromic properties were characterized by ICP-AES/MS, TG/DTA, FTIR, XRD, SEM and UV-Vis diffuse reflectance spectra (DRS), respectively. The elemental analysis results showed that the compounds ((HThr)7PMo12O42•4H2O, (HTyr)7PMo12O42Â.5H2O, (HSer)7PMo12O42•5H2O and (HGlu)7PMo12O42•4H2O) were obtained. The analyses of the TG/DTA, XRD and FTIR confirmed that the four compounds are new phases different from the corresponding reactants and they are composed of the polyoxometalate anions and the corresponding protonated amino acids, respectively. Observation of the SEM revealed that the particle shape (e.g. (HThr)7PMo12O42Â.4H2O nanoplates, (HTyr)7PMo12O42•5H2O nanorods, (HSer)7PMo12O42•5H2O and (HGlu)7PMo12O42•4H2O nanoparticles) depended strongly on the structures of amino acids. This implied that the amino acids can play a structural template agent role in synthesis of the Silverton-type polyoxometalate compounds. After irradiated with ultraviolet light, these samples all exhibited photochromism. Their photochromic mechanism may be explained based on Yamase's photochromic model. These photochromic compounds could be applied to the field of photosensitive materials.

  5. Amino acids inhibit kynurenic acid formation via suppression of kynurenine uptake or kynurenic acid synthesis in rat brain in vitro.

    Sekine, Airi; Okamoto, Misaki; Kanatani, Yuka; Sano, Mitsue; Shibata, Katsumi; Fukuwatari, Tsutomu


    The tryptophan metabolite, kynurenic acid (KYNA), is a preferential antagonist of the α7 nicotinic acetylcholine receptor at endogenous brain concentrations. Recent studies have suggested that increase of brain KYNA levels is involved in psychiatric disorders such as schizophrenia and depression. KYNA-producing enzymes have broad substrate specificity for amino acids, and brain uptake of kynurenine (KYN), the immediate precursor of KYNA, is via large neutral amino acid transporters (LAT). In the present study, to find out amino acids with the potential to suppress KYNA production, we comprehensively investigated the effects of proteinogenic amino acids on KYNA formation and KYN uptake in rat brain in vitro. Cortical slices of rat brain were incubated for 2 h in Krebs-Ringer buffer containing a physiological concentration of KYN with individual amino acids. Ten out of 19 amino acids (specifically, leucine, isoleucine, phenylalanine, methionine, tyrosine, alanine, cysteine, glutamine, glutamate, and aspartate) significantly reduced KYNA formation at 1 mmol/L. These amino acids showed inhibitory effects in a dose-dependent manner, and partially inhibited KYNA production at physiological concentrations. Leucine, isoleucine, methionine, phenylalanine, and tyrosine, all LAT substrates, also reduced tissue KYN concentrations in a dose-dependent manner, with their inhibitory rates for KYN uptake significantly correlated with KYNA formation. These results suggest that five LAT substrates inhibit KYNA formation via blockade of KYN transport, while the other amino acids act via blockade of the KYNA synthesis reaction in brain. Amino acids can be a good tool to modulate brain function by manipulation of KYNA formation in the brain. This approach may be useful in the treatment and prevention of neurological and psychiatric diseases associated with increased KYNA levels.

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

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


    by the peroxidized PUFA. Arachidonic acid and eicosapentaenoic acid showed a dose- and time-dependent cytotoxicity. Two other antioxidants: 50 µM a-tocopherol acid succinate and 1 µM N,N'-diphenyl-1,4-phenylenediamine, both proved more efficient than a-tocopherol phosphate. There was a significant correlation......Rat hepatocyte long-term cultures were utilized to investigate the impact of different polyunsaturated fatty acids (PUFA) on the insulin-induced de novo fatty acid synthesis in vitro. The addition of 0.5 mM albumin-complexed oleic, linoleic, columbinic, arachidonic, eicosapentaenoic...... or docosahexaenoic acid resulted in a marked suppression of fatty acid synthesis. By evaluation of cell viability (determined as the leakage of lactate dehydrogenase (LDH)) it turned our, that the antioxidant used (50 µM a-tocopherol phosphate) had a low antioxidant activity, resulting in cytotoxic effects...

  7. Inhibition of Interjacent Ribonucleic Acid (26S) Synthesis in Cells Infected by Sindbis Virus

    Scheele, Christina M.; Pfefferkorn, E. R.


    The interrelationship of viral ribonucleic acid (RNA) and protein synthesis in cells infected by Sindbis virus was investigated. When cultures were treated with puromycin early in the course of infection, the synthesis of interjacent RNA (26S) was preferentially inhibited. A similar result was obtained by shifting cells infected by one temperature-sensitive mutant defective in RNA synthesis from the permissive (29 C) to the nonpermissive (41.5 C) temperature. Under both conditions, the viral RNA produced appeared to be fully active biologically. Once underway, the synthesis of viral RNA in wild-type Sindbis infections did not require concomitant protein synthesis. PMID:5817400

  8. Reviewing the Tannic Acid Mediated Synthesis of Metal Nanoparticles

    Tufail Ahmad


    Full Text Available Metal nanoparticles harbour numerous exceptional physiochemical properties absolutely different from those of bulk metal as a function of their extremely small size and large superficial area to volume. Naked metal nanoparticles are synthesized by various physical and chemical methods. Chemical methods involving metal salt reduction in solution enjoy an extra edge over other protocols owing to their relative facileness and capability of controlling particle size along with the attribute of surface tailoring. Although chemical methods are the easiest, they are marred by the use of hazardous chemicals such as borohydrides. This has led to inclination of scientific community towards eco-friendly agents for the reduction of metal salts to form nanoparticles. Tannic acid, a plant derived polyphenolic compound, is one such agent which embodies characteristics of being harmless and environmentally friendly combined with being a good reducing and stabilizing agent. In this review, first various methods used to prepare metal nanoparticles are highlighted and further tannic acid mediated synthesis of metal nanoparticles is emphasized. This review brings forth the most recent findings on this issue.

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

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


    Full Text Available

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

  10. Ceramide synthesis from free fatty acids in rat brain: function of NADPH and substrate specificity

    Singh, I.


    At the subcellular level, the synthesis of ceramide from free lignoceric acid and sphingosine in brain required reconstituted enzyme system (particulate fraction, heat-stable and heat-labile factors) and pyridine nucleotide (NADPH). The mitochondrial electron transfer inhibitors (KCN and antimycin A), energy uncouplers (oligomycin and 2,4-dinitrophenol), and carboxyatractyloside, which prevents the transport of ATP and ADP through the mitochondrial wall, inhibit the synthesis of ceramide in the presence of NADPH but have very little effect in the presence of ATP. Similar to the synthesis of ceramide, the synthesis of ATP from NADPH and NADH by the particulate fraction also required cytoplasmic factors (heat-stable and heat-labile factors). Moreover, ATP, but not its analog (AMP-CH2-P-O-P), can replace NADPH, thus suggesting that the function of the pyridine nucleotide is to provide ATP for the synthesis of ceramide. The cytoplasmic factors were not required for the synthesis of ceramide in the presence of ATP. The maximum velocity for synthesis of ceramide from free fatty acids of different chain lengths (C16-C26) was bimodal, with maxima around stearic acid (C18) and behenic acid (C22). The relative rate of synthesis of ceramide parallels the relative distribution of these fatty acids in brain cerebrosides and sulfatides.

  11. Soluble Polymer-Supported Synthesis of α-Amino Acid Derivatives

    XIE Cheng; HU Chun-Ling; ZHANG Gang-Shen; CHEN Zu-Xing


    @@ Due to the central role played by α-amino acid in chemistry and biology, the development of versatile and new methodology for the synthesis of natural and unnatural α-amino acid has emerged as an important and challenging synthetic endeavour for organic chemists.[1] Among the various methodologies reported for α-amino acid synthesis, [2,3] the solid-phase organic synthesis (SPOS) has served as an important approach. [4] However, inherent prob lems on solid supports are reactive site accessibility, site-site interaction and monitoring of the reaction.

  12. Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running


    Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential a...

  13. Amino Acid Synthesis in Seafloor Environments on Icy Worlds

    Flores, Erika; Barge, Laura; VanderVelde, David; Kallas, Kayo; Baum, Marc M.; Russell, Michael J.; Kanik, Isik


    In 2005, the Cassini mission detected plumes erupting from Enceladus' surface, containing carbon dioxide, methane, silica, and possibly ammonia. Subsequent laboratory experiments indicated that the silica particles in the plumes were generated under alkaline conditions and at moderate temperatures of ~90°C (Hsu et al., 2015); one scenario for such conditions would be the existence of alkaline (serpentinization-driven) hydrothermal activity within Enceladus. Alkaline vents are significant since they have been proposed as a likely environment for the emergence of metabolism on the early Earth (Russell et al. 2014) and thus could also provide a mechanism for origin of life on ocean worlds with a water-rock interface. Alkaline vents in an acidic, iron-containing ocean could produce mineral precipitates that could act as primitive enzymes or catalysts mediating organic reactions; for example, metal sulfides can catalyze the reductive amination of pyruvate to alanine (Novikov and Copley 2013). We have conducted experiments testing the synthesis of amino acids catalyzed by other iron minerals that might be expected to precipitate on the seafloor of early Earth or Enceladus. Preliminary results indicate that amino acids as well as other organic products can be synthesized in 1-3 days under alkaline hydrothermal conditions. We also find that the yield and type of organic products is highly dependent on pH and temperature, implying that understanding the specifics of the geochemical hydrothermal gradients on Enceladus (or other ocean worlds) will be significant in determining their potential for synthesizing building blocks for life.Hsu, H.-W. et al. (2015), Nature 519, 207-210.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Novikov Y. and Copley S. D. (2013) PNAS 110, 33, 13283-13288.

  14. Physiological effects of γ-linolenic acid and sesamin on hepatic fatty acid synthesis and oxidation.

    Ide, Takashi; Iwase, Haruka; Amano, Saaya; Sunahara, Saki; Tachihara, Ayuka; Yagi, Minako; Watanabe, Tsuyoshi


    Interrelated effects of γ-linolenic acid (GLA) and sesamin, a sesame lignan, on hepatic fatty acid synthesis and oxidation were examined. Rats were fed experimental diets supplemented with 0 or 2 g/kg sesamin (1:1 mixture of sesamin and episesamin) and containing 100 g/kg of palm oil (saturated fat), safflower oil rich in linoleic acid, or oil of evening primrose origin containing 43% GLA (GLA oil) for 18 days. In rats fed sesamin-free diets, GLA oil, compared with other oils, increased the activity and mRNA levels of various enzymes involved in fatty acid oxidation, except for some instances. Sesamin greatly increased these parameters, and the enhancing effects of sesamin on peroxisomal fatty acid oxidation rate and acyl-CoA oxidase, enoyl-CoA hydratase and acyl-CoA thioesterase activities were more exaggerated in rats fed GLA oil than in the animals fed other oils. The combination of sesamin and GLA oil also synergistically increased the mRNA levels of some peroxisomal fatty acid oxidation enzymes and of several enzymes involved in fatty acid metabolism located in other cell organelles. In the groups fed sesamin-free diets, GLA oil, compared with other oils, markedly reduced the activity and mRNA levels of various lipogenic enzymes. Sesamin reduced all these parameters, except for malic enzyme, in rats fed palm and safflower oils, but the effects were attenuated in the animals fed GLA oil. These changes by sesamin and fat type accompanied profound alterations in serum lipid levels. This may be ascribable to the changes in apolipoprotein-B-containing lipoproteins.

  15. Fatty acid digestion, synthesis and metabolism in broiler chickens and pigs

    Smink, W.


    The impact of variation in the composition of dietary fat on digestion, metabolism and synthesis of fatty acids was studied in broiler chickens and in pigs. In young broiler chickens, digestion of unsaturated fatty acids was substantially higher compared with that of saturated fatty acids. Po

  16. Oxalic Acid Catalyzed Three Component One Pot Synthesis of 3,4-Dihydroquinazolin-4-ones

    SANGSHETTI Jaiprakash-N.; KOKARE Nagnnath-D.; SHINDE Devanand-B.


    An efficient one-pot method for synthesis of an array of 3,4-dihydroquinazolin-4-ones from anthranilicacid, triethyl orthoformate, and anilines using oxalic acid as a catalyst was described. The present protocol offers im-provements for the synthesis of 3,4-dihydroquinazolin-4-ones with regard to short reaction time, high yields of products, and simplicity in operation.

  17. The Synthesis of cis- and trans-Fused Bicyclic Sugar Amino Acids

    Risseeuw, Martijn D.P.; Grotenbreg, Gijsbert M.; Witte, Martin D.; Tuin, Adriaan W.; Leeuwenburgh, Michiel A.; Marel, Gijsbert A. van der; Overkleeft, Herman S.; Overhand, Mark


    Four isomeric bicyclic sugar amino acids (SAAs) were prepared from an α-acetylenic-C-glucoside by employing a Petasis olefination and a ring-closing metathesis (RCM) as key steps. The applicability of the resulting SAAs in solid-phase peptide synthesis was demonstrated by the synthesis of a tetrapep

  18. Ultrasound-assisted synthesis of aliphatic acid esters at room temperature.

    Hobuss, Cristiane B; Venzke, Dalila; Pacheco, Bruna S; Souza, Alexander O; Santos, Marco A Z; Moura, Sidnei; Quina, Frank H; Fiametti, Karina G; Vladimir Oliveira, J; Pereira, Claudio M P


    This work describes the ultrasound-assisted synthesis of saturated aliphatic esters from synthetic aliphatic acids and either methanol or ethanol. The products were isolated in good yields after short reaction times under mild conditions.

  19. Sulfanilic acid catalyzed solvent-free synthesis of 1,5-benzodiazepine derivatives


    Sulfanilic acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepines from o-phenylenediamine and ketones. This method is simple, effective and environmentally friendly and gives better yields.

  20. Simultaneous Synthesis of Dimethyl Carbonate and Poly(ethylene terephthalate) Using Alkali Metals as Catalysts%碱金属化合物催化同时合成碳酸二甲酯和聚对苯二甲酸乙二醇酯

    张丹; 王庆印; 姚洁; 王越; 曾毅; 王公应


    Dimethyl carbonate (DMC) and poly(ethylene terephthalate) was simultaneously synthesized by the transesterification of ethylene carbonate (EC) with dimethyl terephthalate (DMT) in this paper. This reaction is an excellent green chemical process without poisonous substance. Various alkali metals were used as the catalysts. The results showed alkali metals had catalytic activity in a certain extent. The effect of reaction condition was also studied. When the reaction was carried out under the following conditions: the reaction temperature 250℃, molar ratio of EC to DMT 3: 1, reaction time 3h, and catalyst amount 0.004 (molar ratio to DMT), the yield of DMC was 68.9%.

  1. Synthesis of 1-O-methylchlorogenic acid: reassignment of structure for MCGA3 isolated from bamboo (Phyllostachys edulis) leaves

    The first synthesis of 1-O-methylchlorogenic acid is described. The short and efficient synthesis of this compound provides laboratory-scale quantities of the material to investigate its biological properties. The synthesis involved C-1 alkylation of the known (-)-4,5-cyclohexylidenequinic acid lact...

  2. Copper-catalyzed formic acid synthesis from CO2 with hydrosilanes and H2O.

    Motokura, Ken; Kashiwame, Daiki; Miyaji, Akimitsu; Baba, Toshihide


    A copper-catalyzed formic acid synthesis from CO2 with hydrosilanes has been accomplished. The Cu(OAc)2·H2O-1,2-bis(diphenylphosphino)benzene system is highly effective for the formic acid synthesis under 1 atm of CO2. The TON value approached 8100 in 6 h. The reaction pathway was revealed by in situ NMR analysis and isotopic experiments.

  3. Synthesis of stable C-linked ferrocenyl amino acids and their use in solution-phase peptide synthesis.

    Philip, Anijamol T; Chacko, Shibin; Ramapanicker, Ramesh


    Incorporation of ferrocenyl group to peptides is an efficient method to alter their hydrophobicity. Ferrocenyl group can also act as an electrochemical probe when incorporated onto functional peptides. Most often, ferrocene is incorporated onto peptides post-synthesis via amide, ester or triazole linkages. Stable amino acids containing ferrocene as a C-linked side chain are potentially useful building units for the synthesis of ferrocene-containing peptides. We report here an efficient route to synthesize ferrocene-containing amino acids that are stable and can be used in peptide synthesis. Coupling of 2-ferrocenyl-1,3-dithiane and iodides derived from aspartic acid or glutamic acid using n-butyllithium leads to the incorporation of a ferrocenyl unit to the δ-position or ε-position of an α-amino acid. The reduction or hydrolysis of the dithiane group yields an alkyl or an oxo derivative. The usability of the synthesized amino acids is demonstrated by incorporating one of the amino acids in both C-terminus and N-terminus of tripeptides in solution phase.

  4. Distribution, synthesis, and absorption of kynurenic acid in plants.

    Turski, Michal P; Turska, Monika; Zgrajka, Wojciech; Bartnik, Magdalena; Kocki, Tomasz; Turski, Waldemar A


    Kynurenic acid (KYNA) is an endogenous antagonist of the ionotropic glutamate receptors and the α7 nicotinic acetylcholine receptor as well as an agonist of the G-protein-coupled receptor GPR35. In this study, KYNA distribution and synthesis in plants as well as its absorption was researched. KYNA level was determined by means of the high-performance liquid chromatography with fluorescence detection. KYNA was found in leaves, flowers, and roots of tested medicinal herbs: dandelion (Taraxacum officinale), common nettle (Urtica dioica), and greater celandine (Chelidoniummajus). The highest concentration of this compound was detected in leaves of dandelion--a mean value of 0.49 µg/g wet weight. It was shown that KYNA can be synthesized enzymatically in plants from its precursor, L-kynurenine, or absorbed by plants from the soil. Finally, the content of KYNA was investigated in 21 herbal tablets, herbal tea, herbs in sachets, and single herbs in bags. The highest content of KYNA in a maximum daily dose of herbal medicines appeared in St. John's wort--33.75 µg (tablets) or 32.60 µg (sachets). The pharmacological properties of KYNA and its presence in high concentrations in medicinal herbs may suggest that it possesses therapeutic potential, especially in the digestive system and should be considered a new valuable dietary supplement.

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

    Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng, E-mail:


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

  6. Abc Amino Acids: Design, Synthesis, and Properties of New Photoelastic Amino Acids

    Standaert, Robert F [ORNL; Park, Dr Seung Bum [Seoul National University


    Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A in the backbone upon transa?cis photoisomerization. This isomer, designated mpAbc, has substituents at meta and para positions on the inner (azo-linked) and outer rings, respectively. An efficient synthesis of Fmoc-protected mpAbc was executed in which the biaryl components were formed via Suzuki couplings and the azo linkage was formed via amine/nitroso condensation; protected forms of three other Abc isomers were prepared similarly. A decapeptide incorporating mpAbc was synthesized by conventional solid-phase methods and displayed characteristic azobenzene photochemical behavior with optimal conversion to the cis isomer at 360 nm and a thermal cisa?trans half life of 100 min. at 80 AoC.

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

    Joanna Gajowy


    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.

  8. Chemical modification and functionalisation of poly(ethylene terephthalate) fiber

    Kim, I.H.; Kim, S.H. [Sungkyunkwan University, Suwon (Korea)


    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.

  9. A Facile Method for Asymmetric Synthesis of β-Hydroxy-α-amino Acids

    LI,Shuo; LI,Lei; ZHANG,Zhi-Hui; XU,Peng-Fei


    @@ β-Hydroxy-a-amino acids are an important class of amino acids due to their inherent biological investigations[1] and as structural components of more complex biomolecules.[2] β-Hydroxy-a-amino acids have been used as intermediates in the asymmetric synthesis of other compounds.[3] An efficient and convenient concise method for the preparation of optically pure enantiomers of β-hydroxy-α-amino acids would be of general interest.

  10. Synthesis of Nature-Inspired Medium-Sized Fused Heterocycles from Amino Acids.

    Ventosa-Andrés, Pilar; La-Venia, Agustina; Ripoll, Carlos Alfonso Barea; Hradilová, Ludmila; Krchňák, Viktor


    Herein, we describe the synthesis of molecular scaffolds consisting of medium-sized fused heterocycles using amino acids, which are some of the most useful building blocks used by nature as well as chemists to create structural diversity. The acyclic precursors were assembled by using traditional Merrifield solid-phase peptide synthesis, and cyclization was carried out through acid-mediated tandem endocyclic N-acyliminium ion formation, followed by nucleophilic addition with internal nucleophiles. The synthesis of molecular scaffolds consisting of seven-, eight-, and nine-membered rings proceeded with full stereocontrol of the newly generated stereogenic center in most cases.

  11. Chemical Synthesis and Functionalization of Cobalt Ferrite Nanoparticles with Oleic Acid and Citric Acid Encapsulation

    Watawe Shrikant C.


    Full Text Available The functionalized nanoparticles have now a prime importance because of their wide ranging biomedical applications. The particles having size range 30nm-150nm are useful for cell wall interaction specifically the pinocytosis which takes place in all types of cells. The Cobalt ferrite nanoparticles have been synthesized using chemical co- precipitation route and the pH and temperature of the synthesis is controlled to obtain the optimum sized particles. The coating of Sodium Oleate and Citric acid was carried out in aqueous medium at room temperature. The characterization of coated and uncoated particles has been carried out using XRD and IR which confirm the ferrite structure formation. The TGA-DTA analysis shows the coating of magnetic particles. The SEM micrographs reveal the particle size, before and after coating to be in the range of 45 to 90 nm. The saturation magnetization is found to be 16.8 emu/gm.

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

    Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng


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

  13. Epoxy Resin and Polyurethane Compositions from Glycolized Poly (ethylene terephthalate Wastes

    Gintaras MACIJAUSKAS


    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:

  14. Synthesis of chlorogenic acid and p-coumaroyl shikimates from glucose using engineered Escherichia coli.

    Cha, Mi Na; Kim, Hyeon Jeong; Kim, Bong Gyu; Ahn, Joong-Hoon


    Chlorogenic acid and hydroxylcinnamoyl shikimates are major dietary phenolics as well as antioxidants, with recently discovered biological, activities including protection against chemotheraphy side effects and prevention of cardiovascular disease and cancer. Certain fruits and vegetables produce these compounds, although a microbial system can also be utilized for synthesis of chlorogenic acid and hydroxylcinnamoyl shikimates. In this study, we engineered Escherichia coli to produce chlorogenic acid and p-coumaroyl shikimates from glucose. For the synthesis of chlorogenic acid, two E. coli strains were used; one strain for the synthesis of caffeic acid from glucose and the other strain for the synthesis of chlorogenic acid from caffeic acid and quinic acid. The final yield of chlorogenic acid using this approach was approximately 78 mg/l. To synthesize p-coumaroyl shikimates, wild-type E. coli as well as several mutants were tested. Mutant E. coli carrying deletions in three genes (tyrR, pheA, and aroL) produced 236 mg/l of p-coumaroyl shikimates.

  15. The control of ribonucleic acid synthesis in bacteria. The synthesis and stability of ribonucleic acids in relaxed and stringent amino acid auxotrophs of Escherichia coli.

    Gray, W J; Midgley, J E


    The biosynthesis and stability of various RNA fractions was studied in RC(str) and RC(rel) multiple amino acid auxotrophs of Escherichia coli. In conditions of amino acid deprivation, RC(str) mutants were labelled with exogenous nucleotide bases at less than 1% of the rate found in cultures growing normally in supplemented media. Studies by DNA-RNA hybridization and by other methods showed that, during a period of amino acid withdrawal, not more than 60-70% of the labelled RNA formed in RC(str) mutants had the characteristics of mRNA. Evidence was obtained for some degradation of newly formed 16S and 23S rRNA species to heterogeneous material of lower molecular weight. This led to overestimations of the mRNA content of rapidly labelled RNA from such methods as simple examination of sucrose-density-gradient profiles. In RC(rel) strains the absolute and relative rates of synthesis of the various RNA fractions were not greatly affected. However, the stability of about half of the mRNA fraction was increased in RC(rel) strains during amino acid starvation, giving kinetics of mRNA labelling and turnover that were identical with those found in either RC(str) or RC(rel) strains inhibited by high concentrations of chloramphenicol. Coincidence hybridization techniques showed that the mRNA content of amino acid-starved RC(str) auxotrophs was unchanged from that found in normally growing cells. In contrast, RC(rel) strains deprived of amino acids increased their mRNA content about threefold. In such cultures the mRNA content of accumulating newly formed RNA was a constant 16% by wt.

  16. Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

    Hiroyuki Kato


    Full Text Available Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential amino acids. We determined fractional protein synthesis rates (FSR at different time points following exercise. Mixed protein and collagen protein FSRs in skeletal muscle were determined by measuring protein-bound enrichments of hydroxyproline and proline, and by measuring the intracellular enrichment of proline, using injections of flooding d3-proline doses. A leucine-enriched mixture of essential amino acids (or distilled water as a control was administrated 30 min or 1 day post-exercise. The collagen protein synthesis in the vastus lateralis was elevated for 2 days after exercise. Although amino acid administration did not increase muscle collagen protein synthesis, it did lead to augmented mixed muscle protein synthesis 1 day following exercise. Thus, contrary to the regulation of mixed muscle protein synthesis, muscle collagen protein synthesis is not affected by amino acid availability after damage-inducing exercise.

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

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


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

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

    Higgs, Paul G


    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.

  19. Synthesis and characterization of some N-substituted amides of salicylic acid

    Lupea Xenia Alfa; Padure Mirabela


    The synthesis of some N-substituted aromatic amides in the salicylic acid series was achieved, by direct reaction between primary amines and salicylic acid in inert organic solvent, in the presence of PCl3. The compounds that were obtained, partially not described in literature, were characterized by chemical-physical methods.

  20. Synthesis and characterization of some N-substituted amides of salicylic acid

    Lupea Xenia Alfa


    Full Text Available The synthesis of some N-substituted aromatic amides in the salicylic acid series was achieved, by direct reaction between primary amines and salicylic acid in inert organic solvent, in the presence of PCl3. The compounds that were obtained, partially not described in literature, were characterized by chemical-physical methods.

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

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

  2. Microwave-assisted base-free synthesis of trans-cinnamic acids using hypervalent iodonium salts

    Min Zhu; Chao Shentu; Zhong Shi Zhou


    A fast and convenient base-free Heck reaction of acrylic acid with hypervalent iodonium salts was achieved under microwave irradiation in water, providing a simple method for the synthesis of trans-cinnamic acids in good yields in short time.

  3. Design and Synthesis of Chiral Molecular Tweezers Based on Deoxycholic Acid


    A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms.Instead of using toxic phosgene,the triphosgene was employed in synthesis of the molecular tweezers receptors.These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.

  4. Synthesis of β3-Amino Acids via Catalyst- and Solvent-Free Aza-Michael Reaction


    A safe, environmentally friendly and cost-effective method for the synthesis of β-amino acid derivatives has been developed. Treatment of α,β-unsaturated compounds with aliphatic amines furnishes β-amino acid derivatives in good to excellent yields via a catalyst- and solvent-free aza-Michael addition.

  5. Polyethylene terephthalate degradation under reactor neutron irradiation

    Chikaoui, K.; Izerrouken, M.; Djebara, M.; Abdesselam, M.


    This paper is devoted to study the defects generated by reactor neutron in polyethylene terephthalate (PET) films. The explored fast neutron fluence ranges from 2.02×1016 to 2.07×1018 n cm-2. The induced damages were investigated using ultraviolet-visible spectrophotometry (UV-vis), Fourier Transform Infrared spectrometry (FTIR) and X-ray diffraction (XRD). The UV-vis spectra show important changes indicating the degradation of the chemical structure and the creation of new chromophores. FTIR spectra reveal that the intensities of the different absorption bands decrease linearly under fast neutron irradiation. The internal reference band at 1410 cm-1 is used to follow the overall damage during irradiation. The 1342 cm-1 band corresponding to CH2 wagging of trans conformation of crystalline phase show a sharpe linear decrease as the fast neutrons fluence goes up. The creation of the monosubstituted benzene, investigated using the 1610 cm-1 band. It shows a linear increase with fast neutron fluence. It is found from XRD analysis that the diffraction peak (100) intensity is drastically reduced after irradiation at 2.02×1016 n cm-2.

  6. Potency of individual bile acids to regulate bile acid synthesis and transport genes in primary human hepatocyte cultures.

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


    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.

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

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


    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.

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

    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: [University of Arizona, Department of Pharmacology and Toxicology, Tucson, AZ 85721 (United States)


    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

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

    Bunch, Lennart; Liljefors, Tommy; Greenwood, Jeremy R


    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 conformat...... studies on native 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) (IC(50) > 300 microM, [(3)H]AMPA) or kainic acid (IC(50) > 160 microM, [(3)H]kainic acid) receptors nor in binding studies on the cloned iGluR5,6 subtypes (IC(50) > 300 microM, [(3)H]kainic acid)....

  10. Asymmetric synthesis of amino acid precursors in interstellar complex organics by circularly polarized light

    Takano, Yoshinori; Takahashi, Jun-ichi; Kaneko, Takeo; Marumo, Katsumi; Kobayashi, Kensei


    The asymmetric synthesis of amino acid precursors from complex organics have been performed. A gaseous mixture of carbon monoxide, ammonia and water (molecules which are among those identified in the interstellar medium) was irradiated with 3.0 MeV protons to obtain amino acid precursors within high-molecular-weight complex organics of up to 3,000 Da. The amino acid precursor products synthesized were then irradiated with right (R-) or left (L-) ultraviolet circularly polarized light (UV-CPL)...

  11. Synthesis and Characterization of Dual Acidic Ionic Liquids

    Xiao Hua WANG; Guo Hong TAO; Zi Yan ZHANG; Yuan KOU


    Novel ionic liquids with dual acidity, of which the cation contains Bronsted acidity and anions contain Lewis acidity were synthesized. These ionic liquids obtained were identified by NMR,FT-IR, SDT and FAB-MS. Their acidities were determined by pyridine probe on IR spectrography.

  12. Enzymatic Modification of Poly (ethylene terephthalate) Fiber with Lipase from Aspergillus oryzae

    WANG Xiao-hua; LU Da-nian; SHAO Zhi-yu; HONG Feng


    Lipase preparation from Aspergiilus oryzae could act on ester bonds on the surface of poly (ethylene terephthalate) fibers and a possible hydrolytic product mono (2-hydroxyethyl) terephthalate was released. After the iipase modification, there were more carboxyl groups on the treated poly (ethylene terephthalate) fabric surface that resulted in binding with mote cationic dyes. Increased hydrophilicity and antistatic ability of poly (ethylene terephthalate) samples were found based on moisture regain, water contact angle and static half decay time.

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


    The 13C-labeled fatty acids octanoic-1-13C acid and palmitic-l-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 unlabeled fatty acids.

  14. 75 FR 6634 - Polyethylene Terephthalate Film, Sheet, and Strip from India: Final Results of Countervailing...


    ... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip from India: Final Results... terephthalate film, sheet, and strip (PET film) from India for the period January 1, 2007 through December 31, 2007. See Polyethylene Terephthalate Film, Sheet, and Strip from India: Preliminary Results...

  15. 76 FR 76943 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results of Antidumping Duty...


    ... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From India: Final Results... terephthalate film (PET Film) from India.\\1\\ This review covers one producer/exporter of subject merchandise... Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping Duty Administrative...

  16. 76 FR 9745 - Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results of Antidumping Duty...


    ... Film from the People's Republic of China (PRC), for which the scope is essentially identical to the... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From Taiwan: Final Results... terephthalate film (PET Film) from Taiwan. See Polyethylene Terephthalate Film, Sheet, and Strip From...

  17. Safety assessment of modified terephthalate polymers as used in cosmetics.

    Becker, Lillian C; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan


    The safety of 6 modified terephthalate polymers as cosmetic ingredients was assessed. These ingredients mostly function as exfoliants, bulking agents, hair fixatives, and viscosity-increasing agents-nonaqueous. Polyethylene terephthalate (PET) is used in leave-on products up to 100% and in rinse-off products up to 2%. The Cosmetic Ingredient Review Expert Panel (Panel) considered that the PET used in cosmetics is chemically equivalent to that used in medical devices. The Panel determined that the Food and Drug Administration's determination of safety of PET in several medical devices, which included human and animal safety data, can be used as the basis for the determination of safety of PET and related polymers used in cosmetics. Use studies of cosmetic eye products that contain PET demonstrated no ocular irritation or dermal sensitization. The Panel concluded that modified terephthalate polymers were safe as cosmetic ingredients in the practices of use and concentration described in this safety assessment.

  18. Transesterification Kinetics of Dimethyl Terephthalate with 1,4-Butanediol

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


    PBT (polybutylene terephthalate) has excellent mechanical properties such as low absorption, dimensional stability, abrasion resistance. It is used in manufacturing electronic components, the automobile part and the various precise parts. Bis (hydroxybutyl) terephthalate (BHBT) which is a PBT monomer, can be produced by transesterification reaction of DMT (dimethyl terephthalate) with 1,4-butandiol (BD). The kinetics of transesterification reaction of DMT with BD using zinc acetate as a catalyst was studied in a batch reactor. Previous kinetic studies was carried out in a semibatch 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 transesterification reaction were developed and used to characterize the reaction kinetics and the composition distribution of the reaction products. More accurate models than previous models was obtained and found to have a good agreement between model predictions and experimental data.

  19. Tuning Gold Nanorod Synthesis Through Pre-reduction with Salicylic Acid

    Scarabelli, Leonardo; Grzelczak, Marek; Liz-Marzán, Luis M.


    Successful synthesis of gold nanorods requires subtle combination of additives and reducing species. The latter are of major importance, as the reducing power determines the rate of metallic gold formation, which often defines the final shape and anisotropy. Ascorbic acid is a common reducing agent in the synthesis of gold nanorods, but its relatively strong reducing power limits the tunability of the final shape and optical response. We propose here a bimodal reducing agent system comprising...

  20. Role of dehydration catalyst acid properties on one-step DME synthesis over physical mixtures

    Fraga, Marco André; Appel, Lúcia Gorenstin; Farias, Andréa Maria Duarte de; Ramos,F.S.; Borges, Luiz Eduardo Pizarro; Monteiro, José L. F.; Souza-Aguiar, E. F.


    The direct synthesis of dimethyl ether (DME) was studied in a continuous high-pressure unit composed basically of a Berty reactor and online gas chromatograph. A commercial methanol synthesis catalyst and some solid-acid catalysts (alumina. HZSM-S. tungsten-zirconia and sulfated-zirconia) were used as physical mixtures. The dehydration catalysts were characterised by pyridine adsorption followed by IR spectroscopy and tested in the methanol dehydration reaction itself. All samples were active...

  1. Synthesis of novel fullerene α-amino acid conjugates

    Jing Zhang; Yan Xia Wang; Feng Kang; Ying Ya Shao; Zong Jie Li; Xin Lin Yang


    Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas)and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.

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

    Kovács, Viktória; Gondor, Orsolya K.; Szalai, Gabriella; Darkó, Éva; Majláth, Imre; Janda, Tibor; Pál, Magda, E-mail:


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

  3. Synthesis of protected (2S,4R)-2-amino-4-methyldecanoic acid, a proposed component of culicinins

    Wei Zhang; Tian Tian Sun; Duo Mei; Jun Fei Wang; Ying Xia Li


    The protected (2S,4R)-2-amino-4-methyldecanoic acid, a proposed component of culicinins has been synthesized over 10 steps and in total 28% yields using Wittig reaction and Schollkopf amino acid synthesis as key steps.

  4. New hydroxamic acid derivatives of fluoroquinolones: synthesis and evaluation of antibacterial and anticancer properties.

    Rajulu, Gavara Govinda; Bhojya Naik, Halehatty Seephya; Viswanadhan, Abhilash; Thiruvengadam, Jayaraman; Rajesh, Kondodiyil; Ganesh, Sambasivam; Jagadheshan, Hiriyan; Kesavan, Poonimangadu Koppolu


    A series of new hydroxamic acid derivatives (6a-f) at C-3 position of fluoroquinolones were designed and synthesized through multistep synthesis. The design concept involved replacement of the 3-carboxylic acid in fluoquinolones with hydroxamic acid as an acid mimicking group. The synthetic work employed in this work provides a good example for the synthesis of pure hydroxamic acid based fluoroquinolones. The synthesized compounds were characterized by (1)H-NMR, electrospray ionization (ESI)-MS and IR. The new compounds were tested for their in vitro antimicrobial and anti-proliferative activity. Out of the six derivatives, compound 6e exhibited moderate antibacterial activity by inhibiting the growth of Escherichia coli and Klebsiella pneumoniae (MIC: 4.00-8.00 µg/mL). Compounds 6b and 6f displayed good growth inhibition against A549 Lung adenocarcinoma and HCT-116 Colon carcinoma cell lines.

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

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


    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.

  6. Pyrolysis of Polytrimethylene Terephthalate (PTT) Fiber by Pyrolysis Gas Chromatography-Mass Spectroscopy

    QIAN He-sheng


    Pyrolysis of polytrimethylene terephthalate (PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates. At 400℃, pyrolysis of molecular chain could occur, only 13 pyrolysates could be identified. The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃. At 550℃ -750℃, pyrolysis of molecular chain could completely take place, 46 pyrolysates could be found. As the temperature increases, the compositions of pyrolysate are distinctly increased. Several compounds, especially benzoic acid, monopropenyl-p-phthalate, 2 - propenyl benzoate, di - 2 - propenyl ester, 1,4 -benzenedicarboxylic acid, benzene, 1, 5 - hexadiene, biphenyl and 1, 3 - propanediol dibenzoate could be formed. The thermal degradation mechanism, which is determined by structure and amount of the thermal decomposition products, are described. During pyrolysis of polytrimethylene terephthalate, polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain. The chain scissions are followed by the elimination reaction, linkage action and secondary reactions, which bring about a variety fragment.

  7. Myristic acid potentiates palmitic acid-induced lipotoxicity and steatohepatitis associated with lipodystrophy by sustaning de novo ceramide synthesis.

    Martínez, Laura; Torres, Sandra; Baulies, Anna; Alarcón-Vila, Cristina; Elena, Montserrat; Fabriàs, Gemma; Casas, Josefina; Caballeria, Joan; Fernandez-Checa, Jose C; García-Ruiz, Carmen


    Palmitic acid (PA) induces hepatocyte apoptosis and fuels de novo ceramide synthesis in the endoplasmic reticulum (ER). Myristic acid (MA), a free fatty acid highly abundant in copra/palmist oils, is a predictor of nonalcoholic steatohepatitis (NASH) and stimulates ceramide synthesis. Here we investigated the synergism between MA and PA in ceramide synthesis, ER stress, lipotoxicity and NASH. Unlike PA, MA is not lipotoxic but potentiated PA-mediated lipoapoptosis, ER stress, caspase-3 activation and cytochrome c release in primary mouse hepatocytes (PMH). Moreover, MA kinetically sustained PA-induced total ceramide content by stimulating dehydroceramide desaturase and switched the ceramide profile from decreased to increased ceramide 14:0/ceramide16:0, without changing medium and long-chain ceramide species. PMH were more sensitive to equimolar ceramide14:0/ceramide16:0 exposure, which mimics the outcome of PA plus MA treatment on ceramide homeostasis, than to either ceramide alone. Treatment with myriocin to inhibit ceramide synthesis and tauroursodeoxycholic acid to prevent ER stress ameliorated PA plus MA induced apoptosis, similar to the protection afforded by the antioxidant BHA, the pan-caspase inhibitor z-VAD-Fmk and JNK inhibition. Moreover, ruthenium red protected PMH against PA and MA-induced cell death. Recapitulating in vitro findings, mice fed a diet enriched in PA plus MA exhibited lipodystrophy, hepatosplenomegaly, increased liver ceramide content and cholesterol levels, ER stress, liver damage, inflammation and fibrosis compared to mice fed diets enriched in PA or MA alone. The deleterious effects of PA plus MA-enriched diet were largely prevented by in vivo myriocin treatment. These findings indicate a causal link between ceramide synthesis and ER stress in lipotoxicity, and imply that the consumption of diets enriched in MA and PA can cause NASH associated with lipodystrophy.

  8. Synthesis and Bioassay of 4-Substituted 2-Oxoglutaric Acids

    Qiu Yun CHEN; Qing Shan LIU; Christopher J. SCHOFIELD


    Three 2-oxoglutaric acid analogues were synthesized. Their interaction with factorinhibiting hypoxia-inducible factor (FIH) was studied using LC-MS method. The results show that hydrophobic substitutes of 2-oxoglutaric acids have great influence on their inhibitor activity.

  9. A Green Synthesis of Diisopropyl Phosphoryl Amino Acid


    In this paper, we report that diisopropyl phosphoryl amino acid could be prepared with reasonable yields under solvent-free condition by adding amino acid to the mixture of diisopropyl phosphite and N-chlorodiisopropylamine.

  10. Absence of cholesterol synthesis as contrasted with the presence of fatty acid synthesis in some arthropods

    Zandee, D.I.


    1. 1. After administration of acetate-1-14C absence of cholesterol synthesis was demonstrated in the lobster Homarus gammarus (L.), the spider Avicularia avicularia (L.) and in the millepede Graphidostreptus tumuliporus (Karsch). 2. 2. However, the animals utilize acetate for the synthesis of fatty

  11. Synthesis and antibacterial evaluation of 3-Farnesyl-2-hydroxybenzoic acid from Piper multiplinervium.

    Malami, Ibrahim; Gibbons, Simon; Malkinson, John P


    3-Farnesyl-2-hydroxybenzoic acid is an antibacterial agent isolated from the leaves of Piper multiplinervium. This compound has activity against both Gram positive and Gram negative bacteria including Escherichia coli, Staphylococcus aureus and Helicobacter pylori. This research aimed to synthesize a natural antibacterial compound and its analogs. The synthesis of 3-Farnesyl-2-hydroxybenzoic acid consists of three steps: straightforward synthesis involving protection of phenolic hydroxyl group, coupling of suitable isoprenyl chain to the protected aromatic ring at ortho position followed by carboxylation with concomitant deprotection to give the derivatives of the salicylic acid. All the three prenylated compounds synthesized were found to exhibit spectrum of activity against S. aureus (ATCC) having MIC: 5.84×10(-3), 41.46×10(-2) and 6.19×10(-1) μmol/ml respectively. The compounds also displayed activity against resistance strain of S. aureus (SA1119B) having MIC: 5.84×10(-3), 7.29×10(-3) and 3.09×10(-1) μmol/ml respectively. This synthesis has been achieved and accomplished with the confirmation of it structure to that of the original natural product, thus producing the first synthesis of the natural product and providing the first synthesis of its analogs with 3-Farnesyl-2-hydroxybenzoic acid having biological activity higher than that of the original natural product.

  12. Synthesis of alpha-hydroxyphosphonic acids from Lesquerella oil

    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 ...

  13. A Convenient Synthesis of Amino Acid Methyl Esters

    Yaowu Sha


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

  14. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

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


    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…

  15. Synthesis and spectroscopic characterization of fluorescent solid rare earth complexes with hydroxamic acids


    The complexes RE2(DHYA)3 .nH2O in the title bar were synthesized through some reactions oftrivalent rareearth ions. In the process of synthesis, dihydroxamic acids were taken as ligands while the alcohol was taken as a solvent.The ligands included adipylhydroxamic acid (ADHA), p-phthalichydroxamic acid (PPHA), oxalohydroxamic acid (OXHA), butadihydroxamic acid (BDHA), o-phthalichydroxamic acid (OPHA), benzoylhydroxamic acid (BHA), etc.Measured at 25 ℃, the molar conductances in various modes are 13.00-21.05 S. cm2. mol-1, which shows that rare-earth complexes are nonelectrolytes and the hydroxamino groups of the complexes have taken part in bonding. Infrared spectra, ultraviolet spectra, nuclear magnetic resonance (1HNMR) spectra, and fluorescence spectra were used to investigate the complexes. Experiments have proved that the complexes of Eu3+ and Tb3+ with aromatic hydroxamic acids have good fluorescent characteristics.




    Full Text Available The chemical synthesis product is the amide of chlorine salicylic acid andsulphanilamide (5ClSA-SA. This research had as objective the effect of this productfrom salicylic acid class as a potential medicine on the serum transaminasis activity.5ClSA-SA has been administrated intraperitoneal to Wistar rats for 7 daysconsecutively determining ALT and AST transaminasis activities after 5 and 7 days.Serum transaminases had high values compared to the control sample (220% ASTand 237% ALT.This synthesis product can lead to stress that induces increasing of plasmaticenzymes activity, transaminasis being one of those.

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

    Alejandro F. Arteaga


    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.

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

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


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

  19. Synthesis and mesomorphic behaviour of lithocholic acid derivatives

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


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

  20. Racemic synthesis and solid phase peptide synthesis application of the chimeric valine/leucine derivative 2-amino-3,3,4-trimethyl-pentanoic acid.

    Pelà, M; Del Zoppo, L; Allegri, L; Marzola, E; Ruzza, C; Calo, G; Perissutti, E; Frecentese, F; Salvadori, S; Guerrini, R


    The synthesis of non natural amino acid 2-amino-3,3,4-trimethyl-pentanoic acid (Ipv) ready for solid phase peptide synthesis has been developed. Copper (I) chloride Michael addition, followed by a Curtius rearrangement are the key steps for the lpv synthesis. The racemic valine/leucine chimeric amino acid was then successfully inserted in position 5 of neuropeptide S (NPS) and the diastereomeric mixture separated by reverse phase HPLC. The two diastereomeric NPS derivatives were tested for intracellular calcium mobilization using HEK293 cells stably expressing the mouse NPS receptor where they behaved as partial agonist and pure antagonist.

  1. The synthesis of astaxanthin esters,independent of the formation of cysts,highly correlates with the synthesis of fatty acids in Haematococcus pluvialis


    The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty acids, though it is an well known phenomenon that the accumulation of astaxanthin is usually accompanied by the formation of cyst. The red cysts contain more than 30% of fatty acids, with 81% of the unsaturated fatty acids. Taken together, besides a resource of astaxanthin, H. pluvialis would be a good resource of valuable fatty acids.

  2. The synthesis of astaxanthin esters, independent of the formation of cysts, highly correlates with the synthesis of fatty acids in Haematococcus pluvialis

    MIAO FengPing; LU DaYan; ZHANG ChengWu; ZUO JinCheng; GENG YaHong; HU HongJun; LI YeGuang


    The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty acids, though it is an well known phenomenon that the accumulation of astaxanthin is usually accompanied by the formation of cyst. The red cysts contain more than 30% of fatty acids, with 81% of the unsaturated fatty acids. Taken together, besides a resource of astaxanthin, H. Pluvialis would be a good resource of valuable fatty acids.

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

    Nelson, G.; Kelley, D.; Schmidt, P.; Virk, S.; Serrato, C.


    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 /sup 3/H/sub 2/O, enzyme activities were measured spectrophotometrically except for AC which was assayed with /sup 14/C-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.

  4. Amino acid starvation has opposite effects on mitochondrial and cytosolic protein synthesis.

    Mark A Johnson

    Full Text Available Amino acids are essential for cell growth and proliferation for they can serve as precursors of protein synthesis, be remodelled for nucleotide and fat biosynthesis, or be burnt as fuel. Mitochondria are energy producing organelles that additionally play a central role in amino acid homeostasis. One might expect mitochondrial metabolism to be geared towards the production and preservation of amino acids when cells are deprived of an exogenous supply. On the contrary, we find that human cells respond to amino acid starvation by upregulating the amino acid-consuming processes of respiration, protein synthesis, and amino acid catabolism in the mitochondria. The increased utilization of these nutrients in the organelle is not driven primarily by energy demand, as it occurs when glucose is plentiful. Instead it is proposed that the changes in the mitochondrial metabolism complement the repression of cytosolic protein synthesis to restrict cell growth and proliferation when amino acids are limiting. Therefore, stimulating mitochondrial function might offer a means of inhibiting nutrient-demanding anabolism that drives cellular proliferation.

  5. Synthesis of pyrophosphonic acid analogues of farnesyl pyrophosphate

    Valentijn, A.R.P.M.; Berg, O. van den; Marel, G.A. van der; Cohen, L.H.; Boom, J.H. van


    The synthesis of four new analogues (i.e. 3-6) of farnesyl pyrophosphate (FPP), which may function as inhibitor of squalene synthase, is described. Compounds 3 and 4 were readily accessible by reaction of farnesal with diethyl phosphite or dimethyl lithiomethylphosphonate, respectively, followed by

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

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


    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)

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

    Kerridge, John F.


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

  8. The use of poly(ethylene terephthalate)-poly(aniline) composite for trypsin immobilisation

    Caramori, S.S. [Laboratorio de Quimica de Proteinas, Departamento de Bioquimica e Biologia Molecular, Instituto de Ciencias Biologicas, Universidade Federal de Goias, Cx. Postal 131, 74001-970 Goiania-GO (Brazil)], E-mail:; Fernandes, K.F. [Laboratorio de Quimica de Proteinas, Departamento de Bioquimica e Biologia Molecular, Instituto de Ciencias Biologicas, Universidade Federal de Goias, Cx. Postal 131, 74001-970 Goiania-GO (Brazil)], E-mail:


    This paper presents trypsin immobilisation on strips of poly(ethylene terephthalate)-poly(aniline), activated with glutaraldehyde (PET-PANIG) composite. The photomicrography of the material showed changes corresponding to the chemical modifications produced in the steps of synthesis. The immobilisation process was very efficient under optimal conditions (18.6%). The immobilised and free enzyme presented the same pH and temperature optimum. PET-PANIG-trypsin was able to hydrolyse casein, albumin, gelatine, and skimmed milk. Km{sub app} value for PET-PANIG-trypsin was very close to Km of the free enzyme for casein. Immobilised trypsin showed higher stability than the free enzyme, with 100% activity after 14 days of storage at 4 deg. C and 100% operational stability after 4 cycles of use.

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

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


    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...... 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...... 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...

  10. The use of ascorbate as an oxidation inhibitor in prebiotic amino acid synthesis: a cautionary note.

    Kuwahara, Hideharu; Eto, Midori; Kawamoto, Yukinori; Kurihara, Hironari; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei


    It is generally thought that the terrestrial atmosphere at the time of the origin of life was CO(2)-rich and that organic compounds such as amino acids would not have been efficiently formed abiotically under such conditions. It has been pointed out, however, that the previously reported low yields of amino acids may have been partially due to oxidation by nitrite/nitrate during acid hydrolysis. Specifically, the yield of amino acids was found to have increased significantly (by a factor of several hundred) after acid hydrolysis with ascorbic acid as an oxidation inhibitor. However, it has not been shown that CO(2) was the carbon source for the formation of the amino acids detected after acid hydrolysis with ascorbic acid. We therefore reinvestigated the prebiotic synthesis of amino acids in a CO(2)-rich atmosphere using an isotope labeling experiment. Herein, we report that ascorbic acid does not behave as an appropriate oxidation inhibitor, because it contributes amino acid contaminants as a consequence of its reactions with the nitrogen containing species and formic acid produced during the spark discharge experiment. Thus, amino acids are not efficiently formed from a CO(2)-rich atmosphere under the conditions studied.

  11. The Use of Ascorbate as an Oxidation Inhibitor in Prebiotic Amino Acid Synthesis: A Cautionary Note

    Kuwahara, Hideharu; Eto, Midori; Kawamoto, Yukinori; Kurihara, Hironari; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei


    It is generally thought that the terrestrial atmosphere at the time of the origin of life was CO2-rich and that organic compounds such as amino acids would not have been efficiently formed abiotically under such conditions. It has been pointed out, however, that the previously reported low yields of amino acids may have been partially due to oxidation by nitrite/nitrate during acid hydrolysis. Specifically, the yield of amino acids was found to have increased significantly (by a factor of several hundred) after acid hydrolysis with ascorbic acid as an oxidation inhibitor. However, it has not been shown that CO2 was the carbon source for the formation of the amino acids detected after acid hydrolysis with ascorbic acid. We therefore reinvestigated the prebiotic synthesis of amino acids in a CO2-rich atmosphere using an isotope labeling experiment. Herein, we report that ascorbic acid does not behave as an appropriate oxidation inhibitor, because it contributes amino acid contaminants as a consequence of its reactions with the nitrogen containing species and formic acid produced during the spark discharge experiment. Thus, amino acids are not efficiently formed from a CO2-rich atmosphere under the conditions studied.

  12. Synthesis and transdermal properties of acetylsalicylic acid and selected esters


    The primary aim of this study was to determine the transdermal penetration of acetylsalicylic acid and some of its derivatives, to establish a correlation, if any, with selected physicochemical properties and to determine if transdermal application of acetylsalicylic acid and its derivatives will give therapeutic drug concentrations with respect to transdermal flux. Ten derivatives of acetylsalicylic acid were prepared by esterification of acetylsalicyloyl chloride with ten different alcohols...

  13. A Novel Synthesis of β-Hydroxy-α-amino Acids

    ZHANG Zhi-Hui; LI Shuo; XU Pen-gFei


    @@ β-hydroxy-α-amino acids constitute an important class of compounds as naturally occurring amino acids and as components of many complex natural products possessing a wide range of biological activities. [1] As a consequence of the essential role played by these amino acids in the biological systems and their utility as synthetic building blocks, a number of useful strategies have been devised for their preparation. [2

  14. Modulation by Amino Acids: Toward Superior Control in the Synthesis of Zirconium Metal-Organic Frameworks.

    Gutov, Oleksii V; Molina, Sonia; Escudero-Adán, Eduardo C; Shafir, Alexandr


    The synthesis of zirconium metal-organic frameworks (Zr MOFs) modulated by various amino acids, including l-proline, glycine, and l-phenylalanine, is shown to be a straightforward approach toward functional-group incorporation and particle-size control. High yields in Zr-MOF synthesis are achieved by employing 5 equivalents of the modulator at 120 °C. At lower temperatures, the method provides a series of Zr MOFs with increased particle size, including many suitable for single-crystal X-ray diffraction studies. Furthermore, amino acid modulators can be incorporated at defect sites in Zr MOFs with an amino acid/ligand ratio of up to 1:1, depending on the ligand structure and reaction conditions. The MOFs obtained through amino acid modulation exhibit an improved CO2 -capture capacity relative to nonfunctionalized materials.

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

    Canping Pan


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

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

    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


    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.

  17. Differential regulation of protein synthesis by amino acids and insulin in peripheral and visceral tissues of neonatal pigs.

    Suryawan, Agus; O'Connor, Pamela M J; Bush, Jill A; Nguyen, Hanh V; Davis, Teresa A


    The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are maximally stimulated after feeding. In the current study, we examined the individual roles of amino acids and insulin in the regulation of protein synthesis in peripheral and visceral tissues of the neonate by performing pancreatic glucose-amino acid clamps in overnight-fasted 7-day-old pigs. We infused pigs (n = 8-12/group) with insulin at 0, 10, 22, and 110 ng kg(-0.66) min(-1) to achieve approximately 0, 2, 6 and 30 muU ml(-1) insulin so as to simulate below fasting, fasting, intermediate, and fed insulin levels, respectively. At each insulin dose, amino acids were maintained at the fasting or fed level. In conjunction with the highest insulin dose, amino acids were also allowed to fall below the fasting level. Tissue protein synthesis was measured using a flooding dose of L: -[4-(3)H] phenylalanine. Both insulin and amino acids increased fractional rates of protein synthesis in longissimus dorsi, gastrocnemius, masseter, and diaphragm muscles. Insulin, but not amino acids, increased protein synthesis in the skin. Amino acids, but not insulin, increased protein synthesis in the liver, pancreas, spleen, and lung and tended to increase protein synthesis in the jejunum and kidney. Neither insulin nor amino acids altered protein synthesis in the stomach. The results suggest that the stimulation of protein synthesis by feeding in most tissues of the neonate is regulated by the post-prandial rise in amino acids. However, the feeding-induced stimulation of protein synthesis in skeletal muscles is independently mediated by insulin as well as amino acids.

  18. Synthesis And Application Of Natural Polymeric Plasticizer Obtained Through Polyesterification Of Rice Fatty Acid

    Vieira, MGA; da Silva, MA; Macumoto, ACG; dos Santos, LO; Beppu, Mm


    This study includes the synthesis of a new natural plasticizer obtained through esterification reaction of rice fatty acid and polyols, its physicochemical characterization and its preliminary application in polyvinyl chloride (PVC). Monopropylene glycol, octanol and diethylene glycol were used as polyols for esterification reaction. Catalyst Fascat (R) 4100, was also added. Viscosity, acidity and hydroxyl index, moisture content, molar mass, chemical composition (by FTIR) and color were dete...




    The chemical synthesis product is the amide of chlorine salicylic acid andsulphanilamide (5ClSA-SA). This research had as objective the effect of this productfrom salicylic acid class as a potential medicine on the serum transaminasis activity.5ClSA-SA has been administrated intraperitoneal to Wistar rats for 7 daysconsecutively determining ALT and AST transaminasis activities after 5 and 7 days.Serum transaminases had high values compared to the control sample (220% ASTand 237% ALT).This syn...

  20. One-pot Synthesis of Lewis Acidic Ionic Liquids for Friedel-Crafts Alkylation


    Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. The ionic liquids were used as catalyst for Friedel-Crafts alkylation of benzene and 1-dodecene. The turnovers of 1-dodecene were higher than 99%. Monoalkylbenzene selectivity was 98%, while the 2-substituent product selectivity was 45%.

  1. A convenient synthesis of pyrroles catalyzed by acidic resin under solvent-free condition



    A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition. Macroporous strongly acidic styrol resin (D001) as a novel, efficient, cost-effective, and reusable solid acid catalyst for the synthesis of pyrroles under the same conditions. The pyrroles were obtained in high yields in short reaction times.


    Ya-li Su; Xiu-ru Li; Yue-jin Tong; Yue-sheng Li


    A novel AB3-type monomer was prepared from gallic acid and DL-2-aminobutyric acid, and used for the synthesis of the biocompatible hyperbranched poly(ester-amide)s by self-polycondensation. The polymers were characterized via FTIR and NMR spectroscopy and thermal analysis, and the average degree of branching of the polymers was estimated to be 0.75.The polymers with abundant acetyl end groups were found to be amorphous with lower intrinsic viscosity, better thermal stability and excellent solubility.

  3. Improved synthesis of isostearic acid using zeolite catalysts

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

  4. Polyphosphorous acid catalyzed cyclization in the synthesis of cryptolepine derivatives


    11-Oxo-10,11-dihydroxy-5H-indolo[3,2,b]quinoline7-carboxylic acid was obtained specifically by polyphosphorous acid catalyzed cyclization with optimal reaction conditions. Biological assays showed that it potentially inhibits the proteasomal chymotrypsin-like activity in vitro and suppresses breast cancer cell growth.

  5. New phenstatin-fatty acid conjugates: synthesis and evaluation.

    Chen, Jinhui; Brown, David P; Wang, Yi-Jun; Chen, Zhe-Sheng


    New phenstatin-fatty acid conjugates have been synthesized and tested against the KB-3-1, H460, MCF-7 and HEK293 cell lines, with an increase in anti-proliferative activity being observed at the micro-molar level paralleling an increase in un-saturation in the fatty acid component.

  6. Asymmetric synthesis of aromatic β-amino acids using ω-transaminase: Optimizing the lipase concentration to obtain thermodynamically unstable β-keto acids.

    Mathew, Sam; Jeong, Seong-Su; Chung, Taeowan; Lee, Sang-Hyeup; Yun, Hyungdon


    Synthesized aromatic β-amino acids have recently attracted considerable attention for their application as precursors in many pharmacologically relevant compounds. Previous studies on asymmetric synthesis of aromatic β-amino acids using ω-transaminases could not be done efficiently due to the instability of β-keto acids. In this study, a strategy to circumvent the instability problem of β-keto acids was utilized to generate β-amino acids efficiently via asymmetric synthesis. In this work, thermodynamically stable β-ketoesters were initially converted to β-keto acids using lipase, and the β-keto acids were subsequently aminated using ω-transaminase. By optimizing the lipase concentration, we successfully overcame the instability problem of β-keto acids and enhanced the production of β-amino acids. This strategy can be used as a general approach to efficiently generate β-amino acids from β-ketoesters.

  7. Synthesis of quinoxalines in the presence of heteropoly acids

    Fatemeh Hakimia


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

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

    Conti, P; De Amici, M; Bräuner-Osborne, Hans


    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...

  9. Expedient synthesis of triazole-linked glycosyl amino acids and peptides.

    Kuijpers, B.H.M.; Groothuys, S.; Keereweer, A.R.; Quaedflieg, P.J.; Blaauw, R.H.; Delft, F.L. van; Rutjes, F.P.J.T.


    [structure: see text] An expedient, high-yielding synthesis of two types of triazole-linked glycopeptides is described. These novel and stable glycopeptide mimics were prepared via Cu(I)-catalyzed [3 + 2] cycloaddition of either azide-functionalized glycosides and acetylenic amino acids or acetyleni

  10. Synthesis of new hyodeoxycholic acid thiosemicarbazone derivatives under solvent-free conditions using microwave

    Zhi Chuan Shi; Zhi Gang Zhao; Xing Li Liu; Yu Chen


    An efficient and simple method for synthesis of new hyodeoxycholic acid thiosemicarbazone derivatives under solvent-free conditions using microwave has been developed. Its main advantages are short reaction times, good conversions and the environmentally friendly nature of the process. The preliminary results indicate that some of these compounds possess inhibitory effects against E. coli.

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

    Nandurkar, Nitin Subhash; Petersen, Rico; Qvortrup, Katrine


    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-s...

  12. Effect of cholecystectomy on bile acid synthesis and circulating levels of fibroblast growth factor 19

    Barrera, Francisco; Azocar, Lorena; Molina, Hector; Schalper, Kurt A.; Ocares, Marcia; Liberona, Jessica; Villarroel, Luis; Pimentel, Fernando; Perez-Ayuso, Rosa M.; Nervi, Flavio; Groen, Albert K.; Miquel, Juan F.


    Background and rationale for the study. FGF19/15 is a gut-derived hormone presumably governing bile acid (BA) synthesis and gallbladder (GB) refilling. FGF19 mRNA is present in human GB cholangiocytes (hGBECs); however, the physiological significance of GB-derived FGF19 remains unknown. We investiga

  13. Synthesis of 2-(alkylamino-1-phenylethane-1-thiosulfuric acids, potential schistosomicides

    Liliani Salum Alves Moreira


    Full Text Available The total synthesis of seven here-to-fore unreported aromatic aminoalkanethiosulfuric acids, their physical properties and those of the aminoalcohol and bromoalkanamine intermediates are reported. All structures were established by including ¹H and 13C NMR, IR and MS spectroscopy and elemental analysis.

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

    Logrado, Lucio P.L.; Santos, Maria Lucilia dos [Brasilia Univ., DF (Brazil). Inst. de Quimica. Lab. de Isolamento e Transformacao de Moleculas Organicas]. E-mail:; Silveira, Damaris [Brasilia Univ., DF (Brazil). Faculdade de Ciencias da Saude; Romeiro, Luiz A.S. [Universidade Catolica de Brasilia, Taguatinga, DF (Brazil). Nucleo de Quimica Bioorganica e Medicinal; Moraes, Manoel O. de; Cavalcanti, Bruno C.; Costa-Lotufo, Leticia V.; Pessoa, Claudia do O [Ceara Univ., Fortaleza, CE (Brazil). Lab. de Oncologia Experimental


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

  15. 2-(hydroxymethyl)aspartic acid: synthesis, crystal structure, and reaction with a transaminase

    Walsh, J.J.; Metzler, D.E.; Powell, D.; Jacobson, R.A.


    The synthesis and x-ray crystal structure of 2-(hydroxymethyl) aspartic acid and the preliminary evaluation of its interaction with cytosolic aspartate aminotransferase of pig heart are described. A dissociation constant 1.4 mM for the L-2-(hydroxymethyl) aspartate complex with the enzyme was obtained. 2 figures. (DP)

  16. A Meldrum's Acid Catalyzed Synthesis of Bis (indolyl) methanes in Water under Ultrasonic Condition

    WANG,Shun-Yi; JI,Shun-Jun; SU,Xiao-Ming


    A highly effective Meldrum's acid catalyzed synthesis of bis(indol-3-yl)methanes has been developed. This reaction provides the corresponding bis(indol-3-yl)methanes in high yields after short reaction time in the presence of 2 mol% catalyst in water under ultrasonic condition.

  17. Brain-specific modulation of kynurenic acid synthesis in the rat

    Gramsbergen, J B; Hodgkins, P S; Rassoulpour, A;


    This study was designed to investigate modulatory mechanisms that control the synthesis of the neuroprotective endogenous excitatory amino acid receptor antagonist kynurenate. De novo kynurenate formation was examined in vitro using tissue slices from rat brain, liver, and kidney. In slices from ...

  18. A Practical Synthesis of (S)-(+)-2-(6(-methoxyl-2-naphthyl) propionic Acid


    A simplified procedure for enantioselective synthesis of (S)-(+)-2-(6(-methoxyl-2- naphthyl) propionic acid ((S)-(+)-naproxen), starting from (6-methoxy-(-naphthyl) -1-propanone, with D-mannitol as auxiliary catalyzed by SmCl3 in one-pot is described. The yield is 87.5 %(ee value 99 %).

  19. Bis-pyrene-modified unlocked nucleic acids: synthesis, hybridization studies, and fluorescent properties

    Perlíková, Pavla; Ejlersen, Maria; Langkjaer, Niels


    Efficient synthesis of a building block for the incorporation of a bis-pyrene-modified unlocked nucleic acid (UNA) into oligonucleotides (DNA*) was developed. The presence of bis-pyrene-modified UNA within a duplex leads to duplex destabilization that is more profound in DNA*/RNA and less distinc...

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

    Shitole Nana Vikram


    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. Lipase-catalyzed synthesis of oligoesters of 2,5-furandicarboxylic acid with aliphatic diols

    Cruz-Izquierdo, Álvaro; Broek, van den Lambertus A.M.; Serra, Juan L.; Llama, María J.; Boeriu, Carmen G.


    2,5-Furandicarboxylic acid is a platform chemical for the production of biobased polymers and materials. This study reports the synthesis of furan oligoesters via polytransesterification of dimethyl furan-2,5-dicarboxylate and linear α, ω-aliphatic diols with chain length ranging from C2 to C12,

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

    Santosh V Goswami; Prashant B Thorat; Sudhakar R Bhusare


    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.

  3. An acid-stable tert-butyldiarylsilyl (TBDAS) linker for solid-phase organic synthesis.

    Diblasi, Christine M; Macks, Daniel E; Tan, Derek S


    [reaction: see text] A new, robust tert-butyldiarylsilyl (TBDAS) linker has been developed for solid-phase organic synthesis. This linker is stable to both protic and Lewis acidic reaction conditions, overcoming a significant limitation of previously reported silyl linkers. Solid-phase acetal deprotection, olefination, asymmetric allylation, and silyl protecting group deblocking reactions have been demonstrated with TBDAS-linked substrates.

  4. Asymmetric and efficient synthesis of homophenylalanine derivatives via Friedel-Crafts reaction with trifluoromethanesulfonic acid

    Murashige, Ryo; Hayashi, Yuka; Hashimoto, Makoto; 橋本, 誠


    An efficient Friedel-Crafts reaction of TFA-Asp(Cl)-OMe and stoichiometric amounts of benzene was established by using neat trifluoromethanesulfonic acid (TfOH) as solvent and catalyst under a mild condition. This methodology has been applied to many aromatic compounds and enabled synthesis of several homophenylalanine derivatives.

  5. An Unexpected and Efficient Synthesis of Open-chain Derivatives of Bistetronic Acid under Microwave Irradiation

    SHI Feng; MA Ning; ZHOU Dianxiang; ZHANG Ge; JIANG Bo; TU Shujiang


    An unexpected and efficient synthesis of novel open-chain derivatives of bistetronic acid has been successfully achieved in glyclol under microwave irradiation (MW).This method has the prominent advantages of short reaction time,high yield,operational simplicity as well as environmental friendliness.

  6. Incorporation of isosorbide into poly(butylene terephthalate) via solid-state polymerization.

    Sablong, Rafaël; Duchateau, Robbert; Koning, Cor E; de Wit, Gert; va Es, Daan; Koelewijn, Roelof; van Haveren, Jacco


    The biomass-based monomer isosorbide was incorporated into poly(butylene terephthalate) (PBT) by solid-state polymerization (SSP) using the macrodiol monomer BTITB-(OH) 2, which consists of isosorbide (I), terephthalic acid (T), and 1,4-butandiol (B) residues. This macromonomer can be synthesized by a simple one-pot, two-step reaction. Polymers with number-average molecular weights up to 100,000 g x mol (-1) were readily synthesized from various ratios of PBT/BTITB-(OH) 2. Their molecular weights, thermal properties, and colors were compared with corresponding copolyesters that were obtained by melt polycondensation. We found that T m, T c, and especially T g were superior for materials that were obtained by SSP. This is ascribed to differences in the microstructures of both types of copolyesters; the SSP products exhibit a more blocky structure than do the more random melt-polymerized counterparts. The SSP method resulted in much higher molecular weights and much less colored polymers, and it seems to be the preferred route for incorporating biobased monomers that exhibit limited thermal stability into engineering plastics.

  7. [Asymmetric synthesis of aromatic L-amino acids catalyzed by transaminase].

    Xia, Wenna; Sun, Yu; Min, Cong; Han, Wei; Wu, Sheng


    Aromatic L-Amino acids are important chiral building blocks for the synthesis of many drugs, pesticides, fine chemicals and food additives. Due to the high activity and steroselectivity, enzymatic synthesis of chiral building blocks has become the main research direction in asymmetric synthesis field. Guided by the phylogenetic analysis of transaminases from different sources, two representative aromatic transaminases TyrB and Aro8 in type I subfamily, from the prokaryote Escherichia coli and eukaryote Saccharomyces cerevisia, respectively, were applied for the comparative study of asymmetric transamination reaction process and catalytic efficiency of reversely converting keto acids to the corresponding aromatic L-amino acid. Both TyrB and Aro8 could efficiently synthesize the natural aromatic amino acids phenylalanine and tyrosine as well as non-natural amino acid phenylglycine. The chiral HPLC analysis showed the produced amino acids were L-configuration and the e.e value was 100%. L-alanine was the optimal amino donor, and the transaminase TyrB and Aro8 could not use D-amino acids as amino donor. The optimal molar ratio of amino donor (L-alanine) and amino acceptor (aromatic alpha-keto acids) was 4:1. Both of the substituted group on the aromatic ring and the length of fatty acid carbon chain part in the molecular structure of aromatic substrate alpha-keto acid have the significant impact on the enzyme-catalyzed transamination efficiency. In the experiments of preparative-scale transamination synthesis of L-phenylglycine, L-phenylalanine and L-tyrosine, the specific production rate catalyzed by TryB were 0.28 g/(g x h), 0.31 g/(g x h) and 0.60 g/(g x h) and the specific production rate catalyzed by Aro8 were 0.61 g/(g x h), 0.48 g/(g x h) and 0.59 g/(g x h). The results obtained here were useful for applying the transaminases to asymmetric synthesis of L-amino acids by reversing the reaction balance in industry.

  8. Synthesis and transdermal properties of acetylsalicylic acid and selected esters.

    Gerber, Minja; Breytenbach, Jaco C; Hadgraft, Jonathan; du Plessis, Jeanetta


    The primary aim of this study was to determine the transdermal penetration of acetylsalicylic acid and some of its derivatives, to establish a correlation, if any, with selected physicochemical properties and to determine if transdermal application of acetylsalicylic acid and its derivatives will give therapeutic drug concentrations with respect to transdermal flux. Ten derivatives of acetylsalicylic acid were prepared by esterification of acetylsalicyloyl chloride with ten different alcohols. The experimental aqueous solubility, logD and transdermal flux values were determined for acetylsalicylic acid and its derivatives at pH 4.5. In vitro penetration was measured through excised female human abdominal skin in diffusion cells. The experimental aqueous solubility of acetylsalicylic acid (6.56 mg/ml) was higher than that of the synthesised acetylsalicylate derivatives (ranging from 1.76 x 10(-3) to 3.32 mg/ml), and the logD of acetylsalicylic acid (-0.85) was lower than that of its derivatives (ranging from -0.25 to 1.95). There was thus an inverse correlation between the aqueous solubility data and the logD values. The experimental transdermal flux of acetylsalicylic acid (263.83 nmol/cm(2)h) was much higher than that of its derivatives (ranging from 0.12 to 136.02 nmol/cm(2)h).


    Dileep Tiwari


    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.

  10. Polylactic acid (PLA) synthesis and modifications: a review

    Yanling CHENG; Shaobo DENG; Paul CHEN; Roger RUAN


    This article reviews various methods of synthesizing polycondensation and ring-opening polymerization and modifying properties of polylactic acid (PLA), which may be used as biomaterials, such as a drug carrier in a drug delivery system, as a cell scaffold and suture in tissue engineering, and as packaging materials in packaging engineering field. Copolymerization of lactide with other monomers or polymers such as malic acid, polyethylene glycol (PEG), polyglycolic acid (PGA), or dextran, as well as blending polylactide with natural derivatives and other methods of modification are discussed. Surface modifications of PLA-type copolymers, such as surface coating,chemical modification, and plasma treatment are described.

  11. Retinoic acid synthesis and functions in early embryonic development

    Kam Richard Kin Ting


    Full Text Available Abstract Retinoic acid (RA is a morphogen derived from retinol (vitamin A that plays important roles in cell growth, differentiation, and organogenesis. The production of RA from retinol requires two consecutive enzymatic reactions catalyzed by different sets of dehydrogenases. The retinol is first oxidized into retinal, which is then oxidized into RA. The RA interacts with retinoic acid receptor (RAR and retinoic acid X receptor (RXR which then regulate the target gene expression. In this review, we have discussed the metabolism of RA and the important components of RA signaling pathway, and highlighted current understanding of the functions of RA during early embryonic development.

  12. Microbiologically produced carboxylic acids used as building blocks in organic synthesis.

    Aurich, Andreas; Specht, Robert; Müller, Roland A; Stottmeister, Ulrich; Yovkova, Venelina; Otto, Christina; Holz, Martina; Barth, Gerold; Heretsch, Philipp; Thomas, Franziska A; Sicker, Dieter; Giannis, Athanassios


    Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building blocks. Thereby, our biotechnological goal was the development of process fundamentals regarding the variable use of renewable raw materials, the development of a multi purpose bioreactor and application of a pilot plant with standard equipment for organic acid production to minimize the technological effort. Furthermore the development of new product isolation procedures, with the aim of direct product recovery, capture of products or single step operation, was necessary. The application of robust and approved microorganisms, also genetically modified, capable of using a wide range of substrates as well as producing a large spectrum of products, was of special importance. Microbiologically produced acids, like 2-oxo-glutaric acid and 2-oxo-D-gluconic acid, are useful educts for the chemical synthesis of hydrophilic triazines, spiro-connected heterocycles, benzotriazines, and pyranoic amino acids. The chiral intermediate of the tricarboxylic acid cycle, (2R,3S)-isocitric acid, is another promising compound. For the first time our process provides large quantities of enantiopure trimethyl (2R,3S)-isocitrate which was used in subsequent chemical transformations to provide new chiral entities for further usage in total synthesis and pharmaceutical research.Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building

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

    Attallah, Olivia A., E-mail: [Center of Nanotechnology, Nile University, 12677 Giza (Egypt); Pharmaceutical Chemistry Department, Heliopolis University, 11777 El Salam, Cairo (Egypt); Girgis, E. [Solid State Physics Department, National Research Center, 12622 Dokki, Giza (Egypt); Advanced Materials and Nanotechnology Lab, CEAS, National Research Center, 12622 Dokki, Giza (Egypt); Abdel-Mottaleb, Mohamed M.S.A. [Center of Nanotechnology, Nile University, 12677 Giza (Egypt)


    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. - Highlights: • We synthesize nicotinic acid coated magnetite nanorods via hydrothermal technique • Effect of nicotinic acid concentration on the nanorods properties was significant • Nanorods maintained uniform shape with increased concentration of nicotinic acid • Alterations occurred in particle size, mineral phases and magnetics of coated samples.

  14. Synthesis and catalytic application of amino acid based dendritic macromolecules

    Koten, G. van; Gossage, R.A.; Jastrzebski, J.T.B.H.; Ameijde, J. van; Mulders, S.J.E.; Brouwer, Arwin J.; Liskamp, R.M.J.


    The use of amino acid based dendrimers as molecular scaffolds for the attachment of catalytically active organometallic Ni ''pincer'' complexes, via a urea functionality, is described; the dendrimer catalysts have comparable activity to their mononuclear (NCN)NiX analogues.

  15. Synthesis of azo derivatives of 4-aminosalicylic acid

    Zheng Bao Zhao; Hui Xia Zheng; Yuan Gui Wei; Jiang Liu


    For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively.The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, N-salicyloyl glycine acid to get azo derivatives of 4-ASA.The azo derivatives were hydrolyzed under the alkaline condition to get the target products.All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details.New derivatives of 4-ASA were characterized.The synthetic route was reasonable and feasible.

  16. [Clarification on publications concerning the synthesis of acetylsalicylic acid].

    Lafont, O


    Charles Frédéric Gerhardt (1816-1856) mentioned in his Traité de chimie Organique (1854) a publication, in French (realized in 1852 but published in 1853) entitled "Researches on anhydrous organic acids" in which, was reported the reaction of sodium salicylate with acetyl chloride. He thought that the reaction product was an acid anhydride, but obtained really crude acetylsalicylic acid. Later on, but also in 1853, a publication in german, by the same author related the same experiments. Surprisingly only the second publication has been mentioned in most of the historical studies on the subject. Acetyl salicylic acid was identified and synthesised in 1859 by von Gilm by another method and the product obtained by Gerhardt was identified to it in 1869.

  17. Synthesis and Physicochemial Properties of Three Glutaric Acid Diester

    Salma Bte Samidin


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

    Basmadjian, G.P.; Ice, R.D. (Oklahoma Univ., Oklahoma City (USA). College of Pharmacy); Mills, S.L. (Tennessee Univ., Memphis (USA). College of Pharmacy)


    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.

  19. Synthesis and Physicochemial Properties of Three Glutaric Acid Diester

    Salma Bte Samidin


    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...

  20. Synthesis and proton conductibility of ternary germanic heteropoly acids

    SANG Xiaoguang; WU Qingyin


    The ternary germanic heteropoly acids H5GeW11VO40·22H2O and H5GeMo11VOd0.24H2O were synthesized for the first time by the stepwise acidification and the stepwise addition of solution of the component elements. The products were characterized by ICP, IR, UV, XRD and TG-DTA. The proton conductibility and the activation energy of proton conduction of the heteropoly acids were investigated.

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

    S Z Mohamed Shamshuddin; N Nagaraju


    The transesterification of methyl salicylate with phenol has been studied in vapour phase over solid acid catalysts such as ZrO2, MoO3 and SO$^{2-}_{4}$ or Mo(VI) ions modified zirconia. The catalytic materials were prepared and characterized for their total surface acidity, BET surface area and powder XRD patterns. The effect of mole-ratio of the reactants, catalyst bed temperature, catalyst weight, flowrate of reactants, WHSV and time-on-stream on the conversion (%) of phenol and selectivity (%) of salol has been investigated. A good yield (up to 70%) of salol with 90% selectivity was observed when the reactions were carried out at a catalyst bed temperature of 200°C and flow-rate of 10 mL/h in presence of Mo(VI)/ZrO2 as catalyst. The results have been interpreted based on the variation of acidic properties and powder XRD phases of zirconia on incorporation of SO$^{2-}_{4}$ or Mo(VI) ions. The effect of poisoning of acid sites of SO$^{2-}_{4}$ or Mo(VI) ions modified zirconia on total surface acidity, powder XRD phases and catalytic activity was also studied. Possible reaction mechanisms for the formation of salol and diphenyl ether over acid sites are proposed.

  2. Fatty acids induce leukotriene C4 synthesis in macrophages in a fatty acid binding protein-dependent manner.

    Long, Eric K a; Hellberg, Kristina; Foncea, Rocio; Hertzel, Ann V; Suttles, Jill; Bernlohr, David A


    Obesity results in increased macrophage recruitment to adipose tissue that promotes a chronic low-grade inflammatory state linked to increased fatty acid efflux from adipocytes. Activated macrophages produce a variety of pro-inflammatory lipids such as leukotriene C4 (LTC4) and 5-, 12-, and 15-hydroxyeicosatetraenoic acid (HETE) suggesting the hypothesis that fatty acids may stimulate eicosanoid synthesis. To assess if eicosanoid production increases with obesity, adipose tissue of leptin deficient ob/ob mice was analyzed. In ob/ob mice, LTC4 and 12-HETE levels increased in the visceral (but not subcutaneous) adipose depot while the 5-HETE levels decreased and 15-HETE abundance was unchanged. Since macrophages produce the majority of inflammatory molecules in adipose tissue, treatment of RAW264.7 or primary peritoneal macrophages with free fatty acids led to increased secretion of LTC4 and 5-HETE, but not 12- or 15-HETE. Fatty acid binding proteins (FABPs) facilitate the intracellular trafficking of fatty acids and other hydrophobic ligands and in vitro stabilize the LTC4 precursor leukotriene A4 (LTA4) from non-enzymatic hydrolysis. Consistent with a role for FABPs in LTC4 synthesis, treatment of macrophages with HTS01037, a specific FABP inhibitor, resulted in a marked decrease in both basal and fatty acid-stimulated LTC4 secretion but no change in 5-HETE production or 5-lipoxygenase expression. These results indicate that the products of adipocyte lipolysis may stimulate the 5-lipoxygenase pathway leading to FABP-dependent production of LTC4 and contribute to the insulin resistant state.

  3. Synthesis and Bioactivity of (R)-Ricinoleic Acid Derivatives: A Review.

    Pabiś, Sylwia; Kula, Józef


    (R)-Ricinoleic acid (RA) [(12R,9Z)-hydroxyoctadecenoic acid], the main compound of castor seed oil, because of its unusual structure readily undergoes multi-directional chemical and biochemical transformations to produce derivatives with the retained carbon skeleton or with its degradation. Many of these are of high biological activity, as documented by an in vitro study, and possess therapeutic potential. This review article provides an overview of the recent developments in the area of synthesis of RA based compounds with anticancer and antimicrobial activities. Moreover, the antiinflammatory and analgesic properties of some ricinoleic acid derivatives are also highlighted.

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

    Meyhoff, Ulrich; Riber, Ulla; Boas, Ulrik


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

  5. Kinetics of acetic acid synthesis from ethanol over a Cu/SiO2 catalyst

    Voss, Bodil; Schjødt, Niels Christian; Grunwaldt, Jan-Dierk;


    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...

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

    Dev S


    Full Text Available In the present investigation mefenamic acid prodrug of β-cyclodextrins was synthesized. The primary hydroxy group of β-cyclodextrins was used to block the acid group. The synthesis involved a series of protection and deprotection reaction. The ester was evaluated for stability in simulated gastric and intestinal fluid. The hydrolysis of cyclodextrin conjugate in colon is confirmed by the hydrolysis kinetics studies in rat faecal material. The ester was also evaluated for ulcerogenicity. Results of these studies established the primary aim of masking the ulcerogenic potential of free drug, by using 12-fold dose of the normal dose of mefenamic acid and equivalent doses of the ester.

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

    Kalisankar Bera; Dwayaja Nadkarni; Iirishi N N Namboothiri


    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.



    The optical α-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical α-amino acids. This is a new method for the asymmetric synthesis of α-amino acids. The influences of catalyst,temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.

  9. Effect of O-acetylsalicylic acid on lipid synthesis by guinea pig gastric mucosa in vitro

    Spohn, M.; McColl, I.


    The aim of this work was to investigate the involvement of lipids as possible components of the gastric mucosal barrier by studying the synthesis and secretion of lipids by the epithelial cell lining of gastric mucosa and the effect of salicylate on these processes. O-Acetylsalicylic acid reversibly reduced in vitro incorporation of (U-/sup 14/C) and of DL-(2-/sup 14/C) mevalonic acid into lipids by isolated epithelial cells and by intact mucosa of guinea pig stomach, indicating reversible inhibition of lipid synthesis by the tissue in the presence of the drug. Inhibition of incorporation of both precursors into total lipids, into their fatty acid components, and into cholesterol is demonstrated. 19 refs.

  10. Studies on chemical modification and biology of a natural product, gambogic acid (II): Synthesis and bioevaluation of gambogellic acid and its derivatives from gambogic acid as antitumor agents.

    Wang, Jinxin; Ma, Junhai; You, Qidong; Zhao, Li; Wang, Fan; Li, Chong; Guo, Qinglong


    Gambogic acid (GA) has been reported to be a potent apoptosis inducer. The fact that it is amenable to chemical modification makes GA an attractive molecule for the development of anticancer agents. We firstly reported the synthesis of gambogellic acid, which was generated under acid catalysis from readily available GA by a base-catalyzed diene intramolecular annelation. Sequentially, thirteen new compounds were synthesized and their inhibitory activity on HT-29, Bel-7402, BGC-823, and A549 cell lines were evaluated in vitro by MTT assay, and (38, 40)-epoxy-33-chlorogambogellic acid (4) was identified as a BGC-823 cell apoptosis inducer through MTT cell assay, observations of morphological changes, and Annexin-V/PI double-staining assay. Compound 4 showed significant effects in inducing apoptosis and might serve as a potential lead compound for discovery of new anticancer drugs. Further structure-activity relationships (SARs) of gambogic acid derivatives were discussed.

  11. Laser transmission welding of poly(ethylene terephthalate) and biodegradable poly(ethylene terephthalate) - Based blends

    Gisario, Annamaria; Veniali, Francesco; Barletta, Massimiliano; Tagliaferri, Vincenzo; Vesco, Silvia


    Joining of Poly(Ethylene Terephthalate) PET and its biodegradable derivatives is of high relevance to ensure good productive rate, low cost and operational safety for fabrication of medical and electronic devices, sport equipments as well as for manufacturing of food and drug packaging solutions. In the present investigation, granules of PET and PETs modified by organic additives, which promote biodegradation of the polymeric chains, were prepared by extrusion compounding. The achieved granules were subsequently re-extruded to shape thin (330 μm) flat sheets. Substrates cut from these sheets were joined by Laser Transmission Welding (LTW) with a continuous wave High Power Diode Laser (cw-HPDL). First, based on a qualitative evaluation of the welded joints, the most suitable operational windows for PETs laser joining were identified. Second, characterization of the mechanical properties of the welded joints was performed by tensile tests. Accordingly, Young's modulus of PET and biodegradable PET blends was studied by Takayanagi's model and, based on the experimental results, a novel predicting analytical model derived from the mixture rule was developed. Lastly, material degradation of the polymeric joints was evaluated by FT-IR analysis, thus allowing to identify the main routes to thermal degradation of PET and, especially, of biodegradable PET blends during laser processing.

  12. Catabolism of Branched Chain Amino Acids Supports Respiration but Not Volatile Synthesis in Tomato Fruits

    Andrej Kochevenko; Wagner L.Araújo; Gregory S.Maloney; Denise M.Tieman; Phuc Thi Do; Mark G.Taylor; Harry J.Klee; Alisdair R.Fernie


    The branched-chain amino acid transaminases (BCATs) have a crucial role in metabolism of the branched-chain amino acids leucine,isoleucine,and valine.These enzymes catalyze the last step of synthesis and the initial step of degradation of these amino acids.Although the biosynthetic pathways of branched chain amino acids in plants have been extensively investigated and a number of genes have been characterized,their catabolism in plants is not yet completely understood.We previously characterized the branched chain amino acid transaminase gene family in tomato,revealing both the subcellular localization and kinetic properties of the enzymes encoded by six genes.Here,we examined possible functions of the enzymes during fruit development.We further characterized transgenic plants differing in the expression of branched chain amino acid transaminases 1 and 3,evaluating the rates of respiration in fruits deficient in BCAT1 and the levels of volatiles in lines overexpressing either BCAT1 or BCAT3.We quantitatively tested,via precursor and isotope feeding experiments,the importance of the branched chain amino acids and their corresponding keto acids in the formation of fruit volatiles.Our results not only demonstrate for the first time the importance of branched chain amino acids in fruit respiration,but also reveal that keto acids,rather than amino acids,are the likely precursors for the branched chain flavor volatiles.

  13. Synthesis and quantitative structure-property relationships of side chain-modified hyodeoxycholic acid derivatives.

    Sabbatini, Paola; Filipponi, Paolo; Sardella, Roccaldo; Natalini, Benedetto; Nuti, Roberto; Macchiarulo, Antonio; Pellicciari, Roberto; Gioiello, Antimo


    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.

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

    Antimo Gioiello


    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.

  15. Synthesis, structure, and biological applications of α-fluorinated β-amino acids and derivatives.

    March, Taryn L; Johnston, Martin R; Duggan, Peter J; Gardiner, James


    This review gives a broad overview of the state of play with respect to the synthesis, conformational properties, and biological activity of α-fluorinated β-amino acids and derivatives. General methods are described for the preparation of monosubstituted α-fluoro-β-amino acids (Scheme 1). Nucleophilic methods for the introduction of fluorine predominantly involve the reaction of DAST with alcohols derived from α-amino acids, whereas electrophilic sources of fluorine such as NFSI have been used in conjunction with Arndt-Eistert homologation, conjugate addition or organocatalyzed Mannich reactions. α,α-Difluoro-β-amino acids have also been prepared using DAST; however, this area of synthesis is largely dominated by the use of difluorinated Reformatsky reagents to introduce the difluoro ester functionality (Scheme 9). α-Fluoro-β-amino acids and derivatives analyzed by X-ray crystal and NMR solution techniques are found to adopt preferred conformations which are thought to result from stereoelectronic effects associated with F located close to amines, amides, and esters (Figs. 2-6). α-Fluoro amide and β-fluoro ethylamide/amine effects can influence the secondary structure of α-fluoro-β-amino acid-containing derivatives including peptides and peptidomimetics (Figs. 7-9). α-Fluoro-β-amino acids are also components of a diverse range of bioactive anticancer (e.g., 5-fluorouracil), antifungal, and antiinsomnia agents as well as protease inhibitors where such fluorinated analogs have shown increased potency and spectrum of activity.

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

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


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

  17. Synthesis of Enriched 10B Boric Acid of Nuclear Grade

    张雷; 张卫江; 徐姣; 任新


    An economic and effective method of preparing enriched 10B boric acid was established by chemical reac-tion of enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certain conditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factors were investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yield of enriched 10B boric acid could reach 97. 2%and the purity was up to 94. 1%under the following conditions:the tem-perature was 50—60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystal-lization and titration analysis, the purity of the product could reach over 99. 2%from 94.1%.

  18. The Use of Supported Acidic Ionic Liquids in Organic Synthesis

    Rita Skoda-Földes


    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.

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

    Tremblay, Sebastien [Research Center on Aging, Sherbrooke University Geriatric Institute, 1036 Belvedere Street South, Sherbrooke, Quebec, J1H 4C4 (Canada)]. E-mail:; 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)


    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.

  20. Lysophosphatidic acid as a phospholipid mediator: pathways of synthesis.

    Gaits, F; Fourcade, O; Le Balle, F; Gueguen, G; Gaigé, B; Gassama-Diagne, A; Fauvel, J; Salles, J P; Mauco, G; Simon, M F; Chap, H


    From very recent studies, including molecular cloning of cDNA coding for membrane receptors, lysophosphatidic acid (LPA) reached the status of a novel phospholipid mediator with various biological activities. Another strong argument supporting this view was the discovery that LPA is secreted from activated platelets, resulting in its appearance in serum upon blood coagulation. The metabolic pathways as well as the enzymes responsible for LPA production are poorly characterized. However, a survey of literature data indicates some interesting issues which might be used as the basis for further molecular characterization of phospholipases A able to degrade phosphatidic acid.

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

    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 un...... under alkaline and reducing conditions. Assignments of H-1 NMR spectra were achieved by homo- and heteronuclear 1D and 2D correlations. Double pulsed field gradient spin-echo one-dimensional NOESY proved especially valuable for assignment of aromatic protons....

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

    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...... under alkaline and reducing conditions. Assignments of 1H NMR spectra were achieved by homo- and heteronuclear 1D and 2D correlations. Double pulsed field gradient spin-echo one-dimensional NOESY proved especially valuable for assignment of aromatic protons....

  3. Radiation synthesis and characterization of polyacrylic acid hydrogels


    The pH-sensitive polyacrylic acid (PAA) hydrogels were synthesized by gamma-ray irradiation at an ambient temperature. The influences of dose, monomer concentration, cross-linking agent content, pH, and ionic strength on the swelling ratio (SR) of the PAA hydrogels were investigated in detail. The results show that the SR of the hydrogel decreases with an increase in the dose, monomer concentration, and cross-linking agent content. In alkaline solution, the SR of the hydrogels is much higher than that in acid solution. Also, the ionic strength can influence the SR of the hydrogels. The more the concentration, the lower the SR.

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

    Janaína G. Alonso


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

  5. Recent Advances in Substrate-Controlled Asymmetric Induction Derived from Chiral Pool α-Amino Acids for Natural Product Synthesis.

    Paek, Seung-Mann; Jeong, Myeonggyo; Jo, Jeyun; Heo, Yu Mi; Han, Young Taek; Yun, Hwayoung


    Chiral pool α-amino acids have been used as powerful tools for the total synthesis of structurally diverse natural products. Some common naturally occurring α-amino acids are readily available in both enantiomerically pure forms. The applications of the chiral pool in asymmetric synthesis can be categorized prudently as chiral sources, devices, and inducers. This review specifically examines recent advances in substrate-controlled asymmetric reactions induced by the chirality of α-amino acid templates in natural product synthesis research and related areas.

  6. 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

    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


    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)

  7. The Synthesis and Evaluation of Arctigenin Amino Acid Ester Derivatives.

    Cai, En-Bo; Yang, Li-Min; Jia, Cai-Xia; Zhang, Wei-Yuan; Zhao, Yan; Li, Wei; Song, Xing-Zhuo; Zheng, Man-Ling


    The use of arctigenin (ARG), a traditional medicine with many pharmacological activities, has been restricted due to its poor solubility in water. Five amino acid derivatives of ARG have been synthesized using glycine, o-alanine, valine, leucine, and isoleucine, which have t-butyloxy carbonyl (BOC) as a protective group. In this study, we examined the effects of removing these protective groups. The results showed that the amino acid derivatives have better solubility and nitrite-clearing ability than ARG. Among the compounds tested, the amino acid derivatives without protective group were the best. Based on these results, ARG and its two amino acid derivatives without protective group (ARG8, ARG10) were selected to evaluate their anti-tumor activity in vivo at a dosage of 40 mg/kg. The results indicated that ARG8 and ARG10 both exhibit more anti-tumor activity than ARG in H22 tumor-bearing mice. The tumor inhibition rates of ARG8 and ARG10 were 69.27 and 43.58%, which was much higher than ARG. Furthermore, the mice treated with these compounds exhibited less damage to the liver, kidney and immune organs compared with the positive group. Furthermore, ARG8 and ARG10 improved the serum cytokine levels significantly compared to ARG. In brief, this study provides a method to improve the water solubility of drugs, and we also provide a reference basis for new drug development.

  8. Stereoselective synthesis of amino acid derivatives using carbohydrates as templates

    Kunz, Horst; Sager, Wilfried; Pfrengle, Waldemar; Laschat, Sabine; Schanzenbach, Dirk


    Glycosylamines contain the easily cleavable semi-aminal-type N-glycosidic bond. O-Protected glycosylamines, therefore, can advantageously be used as a form of "asymmetric ammonia", for instance, in Strecker syntheses and in Ugi reactions to give amino acid amides as well as in modifications of the Mannich reaction.

  9. First Synthesis of 1,4-Dimethoxy-2-Naphthoxyacetic acid.

    Chinea, Kimberly; Banerjee, Ajoy K


    2-Acetyl-1-hydroxynaphthalene was converted into 1,4-dimethoxy-2-naphthoxyacetic acid in seven steps (methylation, Bayer-Villiger oxidation, hydrolysis, bromination, methylation, alkylation and hydrolysis). 2-Hydroxy-1,4-naphthoquinone on acetylation, aromatization, methylation and hydrolysis, respectively, also yielded the title compound.

  10. Synthesis of 9-oxononanoic acid, a precursor for biopolymers.

    Otte, Konrad B; Kirtz, Marko; Nestl, Bettina M; Hauer, Bernhard


    Polymers based on renewable resources have become increasingly important. The natural functionalization of fats and oils enables an easy access to interesting monomeric building blocks, which in turn transform the derivative biopolymers into high-performance materials. Unfortunately, interesting building blocks of medium-chain length are difficult to obtain by traditional chemical means. Herein, a biotechnological pathway is established that could provide an environmentally suitable and sustainable alternative. A multiple enzyme two-step one-pot process efficiently catalyzed by a coupled 9S-lipoxygenase (St-LOX1, Solanum tuberosum) and 9/13-hydroperoxide lyase (Cm-9/13HPL, Cucumis melo) cascade reaction is proposed as a potential route for the conversion of linoleic acid into 9-oxononanoic acid, which is a precursor for biopolymers. Lipoxygenase catalyzes the insertion of oxygen into linoleic acid through a radical mechanism to give 9S-hydroperoxy-octadecadienoic acid (9S-HPODE) as a cascade intermediate, which is subsequently cleaved by the action of Cm-9/13HPL. This one-pot process afforded a yield of 73 % combined with high selectivity. The best reaction performance was achieved when lipoxygenase and hydroperoxide lyase were applied in a successive rather than a simultaneous manner. Green leaf volatiles, which are desired flavor and fragrance products, are formed as by-products in this reaction cascade. Furthermore, we have investigated the enantioselectivity of 9/13-HPLs, which exhibited a strong preference for 9S-HPODE over 9R-HPODE.

  11. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    Sylvain Rault


    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.

  12. Synthesis and Fungicidal Activities of Pyrimethanil Heterocyclic Acid Salt

    SUN,Xiao-Hong; LIU,Yuan-Fa; CHEN,Bang; JIA,Ying-Qi; YANG,Jian-Wu


    Seven pyrimethanil salts were synthesized by organic base containing nitrogen atom reacting with substituted pyridine acids. They are reported for the first time. Their structures have been confirmed by IR, 1H NMR and elemental analysis. The preliminary toxicity tests indicated that most of them exhibited excellent fungicidal activities.The relationship between the structures and the fungicidal activities of the compounds was discussed.

  13. An amino acid depleted cell-free protein synthesis system for the incorporation of non-canonical amino acid analogs into proteins.

    Singh-Blom, Amrita; Hughes, Randall A; Ellington, Andrew D


    Residue-specific incorporation of non-canonical amino acids into proteins is usually performed in vivo using amino acid auxotrophic strains and replacing the natural amino acid with an unnatural amino acid analog. Herein, we present an efficient amino acid depleted cell-free protein synthesis system that can be used to study residue-specific replacement of a natural amino acid by an unnatural amino acid analog. This system combines a simple methodology and high protein expression titers with a high-efficiency analog substitution into a target protein. To demonstrate the productivity and efficacy of a cell-free synthesis system for residue-specific incorporation of unnatural amino acids in vitro, we use this system to show that 5-fluorotryptophan and 6-fluorotryptophan substituted streptavidin retain the ability to bind biotin despite protein-wide replacement of a natural amino acid for the amino acid analog. We envisage this amino acid depleted cell-free synthesis system being an economical and convenient format for the high-throughput screening of a myriad of amino acid analogs with a variety of protein targets for the study and functional characterization of proteins substituted with unnatural amino acids when compared to the currently employed in vivo methodologies.

  14. Effect Factors in Synthesis of Nicotinic Acid by Electrooxidation of 3-Picoline

    SUN Xiu-yun; ZHANG Yu-min; CAO Xue-jing; ZHANG Heng-bin; LI Fei; XU Yu-ling


    In an electrolytic cell with a proton exchange membrane, nicotinic acid was synthesized at the PbO2 anode. The relationship between the current density and the potential at different concentrations of 3-picoline and sulfuric acid as well as at different temperatures was studied with polarization curves. The effects of the concentrations of sulfuric acid and 3-picoline, the anode potential and the reaction temperature on the selectivity and the current efficiency were explored. The optimum conditions were determined by orthogonal experiments. Under optimum conditions the selectivity and the current efficiency for the synthesis of nicotinic acid might reach 89% and 65%, respectively. The concentrations of 3-picoline and nicotinic acid were analyzed with high performance liquid chromatography and the product was characterized with elemental analysis, chromatography-mass spectrometry and IR spectrometry.

  15. Synthesis and Biological Evaluation of Novel Phosphatidylcholine Analogues Containing Monoterpene Acids as Potent Antiproliferative Agents.

    Anna Gliszczyńska

    Full Text Available The synthesis of novel phosphatidylcholines with geranic and citronellic acids in sn-1 and sn-2 positions is described. The structured phospholipids were obtained in high yields (59-87% and evaluated in vitro for their cytotoxic activity against several cancer cell lines of different origin: MV4-11, A-549, MCF-7, LOVO, LOVO/DX, HepG2 and also towards non-cancer cell line BALB/3T3 (normal mice fibroblasts. The phosphatidylcholines modified with monoterpene acid showed a significantly higher antiproliferative activity than free monoterpene acids. The highest activity was observed for the terpene-phospholipids containing the isoprenoid acids in sn-1 position of phosphatidylcholine and palmitic acid in sn-2.

  16. Synthesis and Biological Evaluation of Novel Phosphatidylcholine Analogues Containing Monoterpene Acids as Potent Antiproliferative Agents

    Gliszczyńska, Anna; Niezgoda, Natalia; Gładkowski, Witold; Czarnecka, Marta; Świtalska, Marta; Wietrzyk, Joanna


    The synthesis of novel phosphatidylcholines with geranic and citronellic acids in sn-1 and sn-2 positions is described. The structured phospholipids were obtained in high yields (59–87%) and evaluated in vitro for their cytotoxic activity against several cancer cell lines of different origin: MV4-11, A-549, MCF-7, LOVO, LOVO/DX, HepG2 and also towards non-cancer cell line BALB/3T3 (normal mice fibroblasts). The phosphatidylcholines modified with monoterpene acid showed a significantly higher antiproliferative activity than free monoterpene acids. The highest activity was observed for the terpene-phospholipids containing the isoprenoid acids in sn-1 position of phosphatidylcholine and palmitic acid in sn-2. PMID:27310666

  17. Synthesis of medronic acid monoesters and their purification by high-performance countercurrent chromatography or by hydroxyapatite

    Elina Puljula; Jouko Vepsäläinen; Petri A. Turhanen


    We achieved the synthesis of important medronic acid monoalkyl esters via the dealkylation of mixed trimethyl monoalkyl esters of medronic acid. Two methods were developed for the purification of medronic acid monoesters: 1) small scale (10–20 mg) purification by using hydroxyapatite and 2) large scale (tested up to 140 mg) purification by high-performance countercurrent chromatography (HPCCC).

  18. Synthesis of medronic acid monoesters and their purification by high-performance countercurrent chromatography or by hydroxyapatite

    Elina Puljula


    Full Text Available We achieved the synthesis of important medronic acid monoalkyl esters via the dealkylation of mixed trimethyl monoalkyl esters of medronic acid. Two methods were developed for the purification of medronic acid monoesters: 1 small scale (10–20 mg purification by using hydroxyapatite and 2 large scale (tested up to 140 mg purification by high-performance countercurrent chromatography (HPCCC.

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

    Stan, Catalina; Stefanache, Alina; Dumitrache, M


    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.

  20. Developmental aspects and factors influencing the synthesis and status of ascorbic Acid in the pig.

    Mahan, D C; Ching, S; Dabrowski, K


    Ascorbic acid synthesis in the pig occurs at mid-pregnancy, but activity of the enzyme l-gulono-gamma-lactone oxidase (GLO) declines thereafter during gestation and remains low when the pig nurses the sow. During late gestation the ascorbic acid concentration in the fetus increases, but serum and liver ascorbic acid concentration in the sow declines without affecting the dam's liver GLO activity. It is presumed that as gestation progresses an increased amount of maternal ascorbic acid is transferred to the fetus and to the mammary gland. Colostrum and milk are rich sources of the vitamin and supply the nursing pig with ascorbic acid. The available data suggest that high amounts of ascorbic acid appear to suppress liver GLO activity in the pig. Upon weaning, when exogenous vitamin C is generally not provided, liver GLO activity and serum ascorbic acid increases. During the initial periods postweaning, some reports have indicated growth benefits of supplemental vitamin C. Body tissues differ in their concentrations of ascorbic acid, but tissues of high metabolic need generally have greater concentrations. The corpus luteum in the female, the testis in the male, and the adrenal glands in all pigs contain greater concentrations of the vitamin. Knockout genes preventing ascorbic acid synthesis in pigs have demonstrated poor skeletal and collagen formation and poor antioxidant protection. Under periods of stress ascorbic acid declines in the adrenal, but the pig rapidly recovers to its resting state once the stressor agent is removed. Although there are periods when supplemental vitamin C has been shown to promote pig performance (e.g., during high environmental stress and early postweaning), supplemental vitamin C has not been shown to routinely enhance pig performance.


    De-zhu Ma; Dong-sheng Li; Ming-chuan Zhao; Mo-zhen Wang; Ran Ye; Xiao-lie Luo


    A series of ethylene oxide-butylene terephthalate (EOBT) segmented copolymers with different soft segment length and hard segment content were synthesized. The compositional heterogeneity was studied by solvent extraction. The results show that the compositional heterogeneity increases when soft segment length and hard segment content increase. The compositional heterogeneity is also reflected in the crystallization behavior and morphology of soft and hard segment in EOBT segmented copolymer. The more compositional heterogeneous the EOBT segmented copolymer is, the more different the morphology and the crystallization behavior between separated fractions. Compared with ethylene oxide-ethylene terephthalate (EOET) segmented copolymer, compositional heterogeneity in EOBT segmented copolymer is weaker. But the compositional heterogeneity in EOBT segmented copolymer with long soft segment and high hard segment content is still obvious.

  2. Pyridine salvage and nicotinic acid conjugate synthesis in leaves of mangrove species.

    Ashihara, Hiroshi; Yin, Yuling; Deng, Wei-Wei; Watanabe, Shin


    The metabolic fate of [carbonyl-14C]nicotinamide was surveyed in leaf disks of seven mangrove species, Bruguiera gymnorrhiza, Rhizophora stylosa, Kandeliaobovata, Sonneratia alba, Pemphis acidula, Lumnitzera racemosa and Avicennia marina, with and without 250 mM NaCl. Uptake of [14C]nicotinamide by leaf disks was stimulated by 250 mM NaCl in K. candel, R. stylosa, A. marina and L. racemosa. [Carbonyl-14C]nicotinamide was converted to nicotinic acid and was utilised for the synthesis of nucleotides and nicotinic acid conjugates. Formation of nicotinic acid by the deaminase reaction was rapid; there was little accumulation of nicotinamide in the disks 3h after administration. Radioactivity from [carbonyl-14C]nicotinamide was incorporated into pyridine nucleotides (mainly NAD and NADP) in all mangrove leaves, and the rates varied from 2% (in L. racemosa) to 15% (S. alba) of the total radioactivity taken up. NaCl generally reduced nicotinic acid salvage for NAD and NADP. In all mangrove leaf disks, the most heavily labelled compounds (up to 70% of total radioactivity) were trigonelline (N-methylnicotinic acid) and/or nicotinic acid N-glucoside. Trigonelline was formed in all mangrove plants, but N-glucoside synthesis was found only in leaves of A. marina and K. obovata. In A. marina, incorporation of radioactivity into N-glucoside (51%) was much greater than incorporation into trigonelline (2%). In general, NaCl stimulates the synthesis of these pyridine conjugates. The rate of decarboxylation of nicotinic acid in roots of A. marina seedlings was much greater than for the corresponding reaction observed in leaves.

  3. Green synthesis of gold-chitosan nanocomposites for caffeic acid sensing.

    Di Carlo, Gabriella; Curulli, Antonella; Toro, Roberta G; Bianchini, Chiara; De Caro, Tilde; Padeletti, Giuseppina; Zane, Daniela; Ingo, Gabriel M


    In this work, colloidal gold nanoparticles (AuNPs) stabilized into a chitosan matrix were prepared using a green route. The synthesis was carried out by reducing Au(III) to Au(0) in an aqueous solution of chitosan and different organic acids (i.e., acetic, malonic, or oxalic acid). We have demonstrated that by varying the nature of the acid it is possible to tune the reduction rate of the gold precursor (HAuCl(4)) and to modify the morphology of the resulting metal nanoparticles. The use of chitosan, a biocompatible and biodegradable polymer with a large number of amino and hydroxyl functional groups, enables the simultaneous synthesis and surface modification of AuNPs in one pot. Because of the excellent film-forming capability of this polymer, AuNPs-chitosan solutions were used to obtain hybrid nanocomposite films that combine highly conductive AuNPs with a large number of organic functional groups. Herein, Au-chitosan nanocomposites are successfully proposed as sensitive and selective electrochemical sensors for the determination of caffeic acid, an antioxidant that has recently attracted much attention because of its benefits to human health. A linear response was obtained over a wide range of concentration from 5.00 × 10(-8) M to 2.00 × 10(-3) M, and the limit of detection (LOD) was estimated to be 2.50 × 10(-8) M. Moreover, further analyses have demonstrated that a high selectivity toward caffeic acid can be achieved without interference from catechin or ascorbic acid (flavonoid and nonphenolic antioxidants, respectively). This novel synthesis approach and the high performances of Au-chitosan hybrid materials in the determination of caffeic acid open up new routes in the design of highly efficient sensors, which are of great interest for the analysis of complex matrices such as wine, soft drinks, and fruit beverages.

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

    Jovičić Mirjana C.


    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

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

    Hartati Hartati


    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:] | View in  |

  6. Role of ferrocyanides in the prebiotic synthesis of α-amino acids.

    Ruiz-Bermejo, Marta; Osuna-Esteban, Susana; Zorzano, María-Paz


    We investigated the synthesis of α-amino acids under possible prebiotic terrestrial conditions in the presence of dissolved iron (II) in a simulated prebiotic ocean. An aerosol-liquid cycle with a prebiotic atmosphere is shown to produce amino acids via Strecker synthesis with relatively high yields. However, in the presence of iron, the HCN was captured in the form of a ferrocyanide, partially inhibiting the formation of amino acids. We showed how HCN captured as Prussian Blue (or another complex compound) may, in turn, have served as the HCN source when exposed to UV radiation, allowing for the sustained production of amino acids in conjunction with the production of oxyhydroxides that precipitate as by-products. We conclude that ferrocyanides and related compounds may have played a significant role as intermediate products in the prebiotic formation of amino acids and oxyhydroxides, such as those that are found in iron-containing soils and that the aerosol cycle of the primitive ocean may have enhanced the yield of the amino acid production.

  7. Squalene mono-oxygenase, a key enzyme in cholesterol synthesis, is stabilized by unsaturated fatty acids.

    Stevenson, Julian; Luu, Winnie; Kristiana, Ika; Brown, Andrew J


    SM (squalene mono-oxygenase) catalyses the first oxygenation step in cholesterol synthesis, immediately before the formation of the steroid backbone at lanosterol. SM is an important control point in the pathway, and is regulated at the post-translational level by accelerated cholesterol-dependent ubiquitination and proteasomal degradation, which is associated with the accumulation of squalene. Using model cell systems, we report that SM is stabilized by unsaturated fatty acids. Treatment with unsaturated fatty acids such as oleate, but not saturated fatty acids, increased protein levels of SM or SM-N100-GFP (the first 100 amino acids of SM fused to GFP) at the post-translational level and partially overcame cholesterol-dependent degradation, as well as reversing cholesterol-dependent squalene accumulation. Maximum stabilization required activation of fatty acids, but not triacylglycerol or phosphatidylcholine synthesis. The mechanism of oleate-mediated stabilization appeared to occur through reduced ubiquitination by the E3 ubiquitin ligase MARCH6. Stabilization of a cholesterol biosynthetic enzyme by unsaturated fatty acids may help maintain a constant cholesterol/phospholipid ratio.

  8. Concise synthesis of the A/BCD-ring fragment of gambieric acid A

    Fuwa, Haruhiko; Fukazawa, Ryo; Sasaki, Makoto


    Gambieric acid A (GAA) and its congeners belong to the family of marine polycyclic ether natural products. Their highly complex molecular architecture and unique biological activities have been of intense interest within the synthetic community. We have previously reported the first total synthesis, stereochemical reassignment, and preliminary structure–activity relationships of GAA. Here we disclose a concise synthesis of the A/BCD-ring fragment of GAA. The synthesis started from our previously reported synthetic intermediate that represents the A/B-ring. The C-ring was synthesized via an oxiranyl anion coupling and a 6-endo cyclization, and the D-ring was forged by means of an oxidative lactonization and subsequent palladium-catalyzed functionalization of the lactone ring. In this manner, the number of linear synthetic steps required for the construction of the C- and D-rings was reduced from 22 to 11. PMID:25629027

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

    Lin, B. L.; Raghavan, V.


    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.

  10. Synthesis, antimicrobial evaluation and QSAR studies of propionic acid derivatives

    Sanjiv Kumar


    Full Text Available A series of Schiff bases (1–17 and esters (18–24 of propionic acid was synthesized in appreciable yield and characterized by physicochemical as well as spectral means. The synthesized compounds were evaluated in vitro for their antimicrobial activity against Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, Gram negative bacterium Escherichia coli and fungal strains Candida albicans and Aspergillus niger by tube dilution method. Results of antimicrobial screening indicated that besides having good antibacterial activity, the synthesized compounds also displayed appreciable antifungal activity and compound 10 emerged as the most active antifungal agent (pMICca and pMICan = 1.93. The results of QSAR studies demonstrated that antibacterial, antifungal and overall antimicrobial activities of synthesized propionic acid derivatives were governed by the topological parameters, Kier’s alpha first order shape index (κα1 and valence first order molecular connectivity index (1χv.

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

    Ana Gil-Mesón


    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.

  12. Enzymatic synthesis of palm olein-based fatty thiohydroxamic acids.

    Al-Mulla, Emad A Jaffar; Yunus, Wan Md Zin Wan; Ibrahim, Nor Azowa Bt; Rahman, Mohd Zaki Ab


    Fatty thiohydroxamic acids (FTAs) have been successfully synthesized from palm olein and thiohydroxamic acid by a one-step lipase catalyzed reaction. The use of immobilized lipase (Lipozyme RMIM) as the catalyst for the preparation reaction provides an easy isolation of the enzyme from the products and other components in the reaction mixture. The FTAs were characterized using Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance ((1)H NMR) technique and elemental analysis. The highest conversion percentage (95 %) was obtained when the process was carried out for 30 hours using urea to palm oil ratio of 6.0: 1.0 at 40 °C. The method employed offers several advantages such as renewable and abundant of the raw material, simple reaction procedure, environmentally friendly process and high yield of the product.




    A branched polyethyleneimine (BPEI) was applied to poly(ethylene terephthalate)(PET) fabric to improve its surface moisture absorption so that the fabric becomes less liable to retention of electrostatic charge. The durability of this treatment was assessed by washing and followed by measurement of charge development on the fabric. The treated samples showed improved surface wetting compared to the untreated. The results are consistent with attachment of the BPEI to the PET surface by a cross-linking mechanism.

  14. Effect of pressure on the crystallization behaviour of polyethylene terephthalate

    Li Li; Huang Rui


    Crystallized polyethylene terephthalate (PET) samples were obtained at high pressures of 200-400 MPa at a temperature of 603 K, and another group of the samples were made at pressures of 250-350 MPa and different temperatures with a fixed supercooling. The samples were investigated by means of differential scanning calorimetry and scanning electron microscopy. Characterization results suggested that high pressure could increase the crystallization rate and promote the thickening process of PET lamellar crystals.

  15. Synthesis and photoactivity of phenylazonaphthalene peptide nucleic acid monomers

    Jin Du Li; Miao Chen; Sheng Liu; Hao Bo Zhang; Zhi Lu Liu


    Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized,and their photoisomerization was examined.The new PNA monomers showed reversible trans-cis isomerization with UV and visible light irradiation,which might be the foundation of photo-regulating the hybridization between PNA containing phenylazonaphthalene unit and DNA.Simultaneously,the fluorescence of the new PNA monomers might make them especially useful as structural probes.

  16. Stereoselective synthesis of L-guluronic acid alginates.

    Dinkelaar, Jasper; van den Bos, Leendert J; Hogendorf, Wouter F J; Lodder, Gerrit; Overkleeft, Herman S; Codée, Jeroen D C; van der Marel, Gijsbert A


    The glycosylation properties of gulopyranosides have been mapped out, and it is shown that gulose has an intrinsic preference for the formation of 1,2-cis-glycosidic bonds. It is postulated that this glycosylation behaviour originates from nucleophilic attack at the oxacarbenium ion, which adopts the most favourable 3H4 conformation. Building on the stereoselectivity of gulose, a guluronic acid alginate trisaccharide was assembled for the first time by using gulopyranosyl building blocks.


    HE Binlin; WANG Linfu; CHEN Weizhu


    A series of macromolecular copolymers of styrene and divinyl-benzene were prepared in the presence of iso-octanol or 2-ethyl butyl alcohol. The factors which affected the physical structures of the copolymer were discussed. The macroporous amido-phosphonic acid resin was obtained after the acetylation, phosphonylation and amination of the crosslinked polystyrene. The factors which affected each reaction were studied and the change of physical structures of the copolymer were discussed.

  18. Electrochemical Dicarboxylation of Styrene: Synthesis of 2-Phenylsuccinic Acid

    WANG, Huan; LIN, Mei-Yu; FANG, Hui-Jue; CHEN, Ting-Ting; LU, Jia-Xing


    Electrochemical dicarboxylation of styrene in the presence of atmospheric pressure of CO2 with a Ti cathode monium bromide to give 2-phenylsuccinic acid. Influences of the nature of the electrodes, the current density, the passed charge and the temperature on electrolysis were studied to optimize the electrolytic conditions, with the maximal isolated yield to be 86.07%. The mechanism of the elelctrocarboxylation process has been studied by cyclic voltammetry.

  19. First synthesis of thia steroids from cholic acid.

    Ibrahim-Ouali, Malika; Rocheblave, Luc


    Heterosteroids remain interesting due to their potential biological activities. This prompted us to synthesize novel thia steroids possessing the heteroatom in the A-ring. We set out to describe a new and versatile method for preparing 3-thia steroids from cholic acid via a selective oxidation of one hydroxyl group, a Baeyer-Villiger oxidation and a photolysis as the key steps. The characteristic (1)H and (13)C NMR spectroscopic features of the synthesized compounds are reported.

  20. Microwave Irradiation Promoted Synthesis of Aryloxy Acetic Acids

    LIN Min; ZHOU Jin-mei; XIA Hai-ping; YANG Rui-feng; LIN Chen


    Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%-97.4%) were obtained when the molar ratio of the reactants was n(ArOH) : n(NaOH): n(ClCH2CO2H) =1: 2.5: 1.2 with microwave irradiation power of 640 W for 65-85 s.

  1. A C2-symmetric chiral pool-based flexible strategy: synthesis of (+)- and (-)-shikimic acids, (+)- and (-)-4-epi-shikimic acids, and (+)- and (-)-pinitol.

    Ananthan, Bakthavachalam; Chang, Wan-Chun; Lin, Jhe-Sain; Li, Pin-Hui; Yan, Tu-Hsin


    Via combination of a novel acid-promoted rearrangement of acetal functionality with the controlled installation of the epoxide unit to create the pivotal epoxide intermediates in enantiomerically pure form, a simple, concise, flexible, and readily scalable enantiodivergent synthesis of (+)- and (-)-shikimic acids and (+)- and (-)-4-epi-shikimic acids has emerged. This simple strategy not only provides an efficient approach to shikimic acids but also can readily be adopted for the synthesis of (+)- and (-)-pinitols. These concise total syntheses exemplify the use of pivotal allylic epoxide 14 and its enantiomer ent-14. A readily available inexpensive C2-symmetric L-tartaric acid (7) served as key precursor. In general, the strategy here provides a neat example of the use of a four-carbon chiron and offers a good account of the synthesis of functionalized cyclohexane targets.

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

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


    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.

  3. Glutamic Acid - Amino Acid, Neurotransmitter, and Drug - Is Responsible for Protein Synthesis Rhythm in Hepatocyte Populations in vitro and in vivo.

    Brodsky, V Y; Malchenko, L A; Konchenko, D S; Zvezdina, N D; Dubovaya, T K


    Primary cultures of rat hepatocytes were studied in serum-free media. Ultradian protein synthesis rhythm was used as a marker of cell synchronization in the population. Addition of glutamic acid (0.2 mg/ml) to the medium of nonsynchronous sparse cultures resulted in detection of a common protein synthesis rhythm, hence in synchronization of the cells. The antagonist of glutamic acid metabotropic receptors MCPG (0.01 mg/ml) added together with glutamic acid abolished the synchronization effect; in sparse cultures, no rhythm was detected. Feeding rats with glutamic acid (30 mg with food) resulted in protein synthesis rhythm in sparse cultures obtained from the rats. After feeding without glutamic acid, linear kinetics of protein synthesis was revealed. Thus, glutamic acid, a component of blood as a non-neural transmitter, can synchronize the activity of hepatocytes and can form common rhythm of protein synthesis in vitro and in vivo. This effect is realized via receptors. Mechanisms of cell-cell communication are discussed on analyzing effects of non-neural functions of neurotransmitters. Glutamic acid is used clinically in humans. Hence, a previously unknown function of this drug is revealed.


    王申军; 马瑞杰; 菅秀君; 贾庆龙; 楚庆岩


    The paper introduced the application and synthesis methods for salicylic acid, and described emphatically green synthesis methods with good social and economic benefits prospect.%介绍水杨酸的应用及其合成方法,并对有社会和经济效益前景的绿色合成方法进行阐述。

  5. In situ synthesis of peptide nucleic acids in porous silicon for drug delivery and biosensing.

    Beavers, Kelsey R; Mares, Jeremy W; Swartz, Caleb M; Zhao, Yiliang; Weiss, Sharon M; Duvall, Craig L


    Peptide nucleic acids (PNA) are a unique class of synthetic molecules that have a peptide backbone and can hybridize with nucleic acids. Here, a versatile method has been developed for the automated, in situ synthesis of PNA from a porous silicon (PSi) substrate for applications in gene therapy and biosensing. Nondestructive optical measurements were performed to monitor single base additions of PNA initiated from (3-aminopropyl)triethoxysilane attached to the surface of PSi films, and mass spectrometry was conducted to verify synthesis of the desired sequence. Comparison of in situ synthesis to postsynthesis surface conjugation of the full PNA molecules showed that surface mediated, in situ PNA synthesis increased loading 8-fold. For therapeutic proof-of-concept, controlled PNA release from PSi films was characterized in phosphate buffered saline, and PSi nanoparticles fabricated from PSi films containing in situ grown PNA complementary to micro-RNA (miR) 122 generated significant anti-miR activity in a Huh7 psiCHECK-miR122 cell line. The applicability of this platform for biosensing was also demonstrated using optical measurements that indicated selective hybridization of complementary DNA target molecules to PNA synthesized in situ on PSi films. These collective data confirm that we have established a novel PNA-PSi platform with broad utility in drug delivery and biosensing.

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

    T. Catalina Adarme-Vega


    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 Δ-6-elongase-encoding gene in salinities of 5 and 10 ppt compared to higher salinity levels. The expression of the gene encoding β-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.

  7. Clean synthesis of biodiesel over solid acid catalysts of sulfonated mesopolymers


    FDU-15-SO3H,a solid acid material prepared from the sulfonation of FDU-15 mesoporous polymer,has been demonstrated to serve as an efficient catalyst in the esterification of palmitic acid with methanol as well as in the transesterification of fatty acid-edible oil mixture.FDU-15-SO3H achieved an acid conversion of 99.0% when the esterification was carried out at 343 K with a methanol/palmitic acid molar ratio of 6:1 and 5 wt% catalyst loading.It was capable of giving 99.0% yield of fatty acid methyl esters (FAME) when the transesterification of soybean oil was performed at 413 K and the methanol/oil weight ratio of 1:1.FDU-15-SO3H was further applied to the transesterification/esterification of the oil mixtures with a varying ratio of soybean oil to palmitic acid,which simulated the feedstock with a high content of free fatty acids.The yield of FAME reached 95% for the oil mixtures containing 30 wt% palmitic acid.This indicated the sulfonated mesopolymer was a potential catalyst for clean synthesis of fuel alternative of biodiesel from the waste oil without further purification.

  8. Manufacturing, structure and properties of recycled polyethylene terephthalate /liquid crystal polymer/montmorillonite clay nanocomposites

    Japins, Guntis; Berzina, Rita; Zicans, Janis; Merijs Meri, Remo; Ivanova, Tatjana; Kalkis, Valdis; Reinholds, Ingars


    Polyethylene terephthalate (PET)/liquid crystal polymer (LCP)/monthmorillonite clay (MMT) compositions were obtained by melt mixing. Their mechanical, structural, rheological and thermal properties were investigated.

  9. Efficient Fixation of Carbon Dioxide by Electrolysis - Facile Synthesis of Useful Carboxylic Acids -

    Masao Tokuda


    Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide (scCO2) has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.

  10. Stereoselective Synthesis of α-Amino-C-phosphinic Acids and Derivatives

    José Luis Viveros-Ceballos


    Full Text Available α-Amino-C-phosphinic acids and derivatives are an important group of compounds of synthetic and medicinal interest and particular attention has been dedicated to their stereoselective synthesis in recent years. Among these, phosphinic pseudopeptides have acquired pharmacological importance in influencing physiologic and pathologic processes, primarily acting as inhibitors for proteolytic enzymes where molecular stereochemistry has proven to be critical. This review summarizes the latest developments in the asymmetric synthesis of acyclic and phosphacyclic α-amino-C-phosphinic acids and derivatives, following in the first case an order according to the strategy used, whereas for cyclic compounds the nitrogen embedding in the heterocyclic core is considered. In addition selected examples of pharmacological implications of title compounds are also disclosed.


    堵文斌; 王继元; 朱庆奋; 陈韶辉


    A series of Pd/C catalysts for hydropurification of crude terephthalic acid (CTA)were prepared by impregnating with solutions having various pH values, and the prepared catalysts were characterized by XRD and TEM techniques. Effects of impregnation pH values on the performance of catalyst during removing p-carboxy benzaldehyde (4-CBA), the main impurity in CTA, were investigated. Results showed that catalyst prepared with an impregnation solution pH value of 3.0 exhibited the best catalytic activity, under a reaction temperature of 280 ℃, H2 partial pressure of 0. 6 MPa and a reaction time of 1.0 h,the conversion of 4-CBA over said Pd/C catalyst was almost 100 %. In this catalyst the palladium particles were highly dispersed on the surface of active carbon and presented as microcrystalline structure. A comparison study was carried out between said Pd/C catalyst (prepared at pH value of 3.0 )and an import catalyst. Under severe testing conditions and after repeating testing, the deactivation tendency and palladium sintering behavior of these two catalysts were similar, which indicated that the hydropurification performance of these two catalysts was in the same level.%采用不同pH值的浸渍液制备了粗对苯二甲酸(CTA)加氧精制Pd/C催化剂,考察了浸渍液的pH值对CTA中的主要杂质对羧基苯甲醛(4-CBA)的加氢精制性能的影响,并采用XRD、TEM等手段对催化剂进行了表征.结果表明,浸渍液的pH值为3.0时,金属Pd以微晶的形式高度分散在活性炭载体上,Pd/C催化剂的活性最高,在反应温度280℃、H2分压0.6 MPa、反应时间1.0 h的条件下,Pd/C催化剂上的4-CBA的转化率接近100%.经过多次苛刻的重复反应试验,pH值为3.0条件下制备的Pd/C催化剂与某进口催化剂的活性衰减趋势以及Pd晶粒的烧结情况相当,说明自制Pd/C催化剂的加氢性能已经达到该进口催化剂的性能水平.

  12. Enzyme-catalyzed Transesterification of Unusual Substrate: Synthesis of Acyclovir and L-ascorbic Acid (Vitamin C) Vinyl Esters


    The synthesis of acyclovir and L-ascorbic acid with divinyladipate was performed with alkaline protease from Bacillus subtilis and lipase from Lipozyme (immobilized from Mucor miehei) in different anhydrous organic solvents. Two corresponding derivatives were obtained.

  13. A practical synthesis of 3,4-diethoxybenzthioamide based on Friedel-Crafts reaction with potassium thiocyanate in methanesulfonic acid.

    Aki, Shinji; Fujioka, Takafumi; Ishigami, Masashi; Minamikawa, Jun-ichi


    The synthesis of 3,4-diethoxybenzthioamide, the key intermediate for OPC-6535, is achieved by employing Friedel-Crafts reaction of 1,2-diethoxybenzene with potassium thiocyanate in methanesulfonic acid at ambient temperature.

  14. Synthesis and anticancer evaluation of alpha-lipoic acid derivatives.

    Zhang, Shi-Jie; Ge, Qiu-Fu; Guo, Dian-Wu; Hu, Wei-Xiao; Liu, Hua-Zhang


    alpha-Lipoic acid derivatives were synthesized and evaluated for their in vitro anticancer activities against NCI-460, HO-8910, KB, BEL-7402, and PC-3 cell lines. The results, for most compounds exhibited dose-dependent inhibitory property and several compounds had good inhibitions at the dose of 100 microg/mL. Compound 17 m was further selected for in vivo evaluation against S180 xenograft in ICR mice, which had 24.7% tumor-weight inhibition through intragastric administration of 200mg/kg of body weight. Moreover, the LD(50) in mice for 17 m through ig exceeded 1000 mg/kg of body weight.

  15. Synthesis, preliminary bioevaluation and computational analysis of caffeic acid analogues.

    Liu, Zhiqian; Fu, Jianjun; Shan, Lei; Sun, Qingyan; Zhang, Weidong


    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.

  16. Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

    Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory


    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. Enzymatic synthesis of enantiopure alpha- and beta-amino acids by phenylalanine aminomutase-catalysed amination of cinnamic acid derivatives.

    Wu, Bian; Szymanski, Wiktor; Wietzes, Piet; de Wildeman, Stefaan; Poelarends, Gerrit J; Feringa, Ben L; Janssen, Dick B


    The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of alpha-phenylalanine to beta-phenylalanine, an important step in the biosynthesis of the N-benzoyl phenylisoserinoyl side-chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)-cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring-substituted (E)-cinnamic acids can serve as a substrate in PAM-catalysed ammonia addition reactions for the biocatalytic production of several important beta-amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non-natural aromatic alpha- and beta-amino acids in excellent enantiomeric excess (ee >99 %). The internal 5-methylene-3,5-dihydroimidazol-4-one (MIO) cofactor is essential for the PAM-catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent.

  18. Total synthesis of gracilioether F. Development and application of Lewis acid promoted ketene–alkene [2+2] cycloadditions and late-stage C—H oxidation

    Rasik, Christopher M. [Indiana Univ., Bloomington, IN (United States); Brown, M. Kevin [Indiana Univ., Bloomington, IN (United States)


    The first synthesis of gracilioether F, a polyketide natural product with an unusual tricyclic core and five contiguous stereocenters, is described. Key steps of the synthesis include a Lewis acid promoted ketene–alkene [2+2] cycloaddition and a late-stage carboxylic acid directed C(sp³)—H oxidation. The synthesis requires only eight steps from norbornadiene.

  19. Enzymatic Synthesis of Dipeptide Derivatives Containing Noncoded Amino Acids in Organic Solvents

    YANG,Hong(杨洪); ZHOU,Chuang(周闯); TIAN,Gui-Ling(田桂玲); YE,Yun-Hua(叶蕴华)


    A series of dipeptide derivatives containing non-coded amino acis, N-Boc-4-X-Phe-Ala-NHNHNHPh (X= Cl, Br, I, NO2),were synthesized by using thermoase in organic solvents. The physical data were consistent with the same samples prepared by 3-( diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4 (3H)-one (DEPBT). Influence of different substituted groups of the non-coded amino acids and different organic solvents on the enzymatic peptide synthesis was studied.

  20. Lewis acid promoted dual bond formation: facile synthesis of dihydrocoumarins and spiro-tetracyclic dihydrocoumarins.

    Niharika, Pedireddi; Ramulu, Bokka Venkat; Satyanarayana, Gedu


    Lewis acid (FeCl3) mediated dual bond (C-C and C-O) formation for synthesis of 3,4-dihydrocoumarins is presented. This method has successfully delivered a number of dihydrocoumarins containing dense functionalities on the aromatic ring. Significantly, the present method enabled achieving dihydrocoumarins with tertiary as well as quaternary carbon atoms at the benzylic position. Gratifyingly, the novel spiro-tetracyclic lactones have also been dextrously prepared using this process.

  1. One-step synthesis of 1-chloro-3-arylacetone derivatives from arylacetic acids.

    Zacuto, Michael J; Dunn, Robert F; Figus, Margaret


    A practical one-step method has been developed to prepare α-chloroketones from readily available, inexpensive phenylacetic acid derivatives. The method utilizes the unique reactivity of an intermediate Mg-enolate dianion, which displays selectivity for the carbonyl carbon of chloromethyl carbonyl electrophiles. Decarboxylation of the intermediate occurs spontaneously during the reaction quench. The utility of the reaction products has been demonstrated through the total synthesis of the natural product cimiracemate B.


    Anees Pangal


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

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

    León, John Jairo Castillo; Rindzevicius, Tomas; Wu, Kaiyu


    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....

  4. Synthesis and biological evaluation of new salvinorin A analogues incorporating natural amino acids.

    Fichna, Jakub; Lewellyn, Kevin; Yan, Feng; Roth, Bryan L; Zjawiony, Jordan K


    The synthesis and in vitro evaluation of a new series of salvinorin A analogues substituted at the C(2) position with natural amino acids is reported. Compound 12, containing Val, displayed high affinity and full agonist activity at the kappa-opioid receptor. Analogues with bulky and/or aromatic residues were inactive, showing the importance of size and electronegativity of C(2)-substituents for binding affinity of salvinorin A derivatives.

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

    Panda, Biswajit, E-mail:; Goyal, P. S. [Pillai’s Institute of Information Technology, Engineering, Media Studies and Research, Dr. K. M. Vasudevan Pillai’s Campus, New Panvel, 410 206 (India)


    Magnetic nano particles of Fe{sub 3}O{sub 4} coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe{sup 2+} and Fe{sup 3+} 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 Fe{sub 3}O{sub 4} 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 Fe{sub 3}O{sub 4} particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe{sub 3}O{sub 4} particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm.


    LI Zhongqin; GUO Daiping; HUANG Xinghua; YANG Kai; XU Xiaoping


    In this paper, the poly(acrylamide) hydrogel used to immobilize saccharomyces cerevisiae for asymmetric synthesis of R(-)-mandelic acid was prepared with free radical ploymerization in deionized water at room temperature under nitrogen atmosphere. The influence of the composition of hydrogel, loading amount of cells and culture conditions on the asymmetric synthesis was investigated. Results show that PAAm hydrogel is a feasible carrier for immobilization of cells which is a potential alternative method to prepare enantiomerically pure R(-)-mandelic acid.

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

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


    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.


    M. V. C. B. Cortes


    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 β-amino acids from other substituteddihydrothymines.

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

    Rabe, Patrick; Klapschinski, Tim A.; Brock, Nelson L.


    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......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...

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

    Patrick Rabe


    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.

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

    Camilo A. Navarro D.


    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.

  12. Total synthesis of leopolic acid A, a natural 2,3-pyrrolidinedione with antimicrobial activity

    Dhavan, Atul A; Kaduskar, Rahul D; Musso, Loana; Scaglioni, Leonardo; Martino, Piera Anna


    Summary The first total synthesis of leopolic acid A, a fungal metabolite with a rare 2,3-pyrrolidinedione nucleus linked to an ureido dipeptide, was designed and carried out. Crucial steps for the strategy include a Dieckmann cyclization to obtain the 2,3-pyrrolidinedione ring and a Wittig olefination to install the polymethylene chain. An oxazolidinone-containing leopolic acid A analogue was also synthesized. The antibacterial activity showed by both compounds suggests that they could be considered as promising candidates for future developments. PMID:27559415

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

    Mario J. Simirgiotis


    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.

  14. Photocatalytic Synthesis of Gold Nanoparticles Using Preyssler Acid and Their Photocatalytic Activity



    Preyssler acid H14[NaP5W30O110] was used as reducing agent and stabilizer for the synthesis of gold nanoparticles by photolysis of Au(Ⅲ)/Preyssler acid/propan-2-ol solution. Preyssler acid plays both the role of transferring electrons from propan-2-ol to Au(Ⅲ) and stabilizing the nanoparticles. Propan-2-ol was used as sacrificial reagent for the photoformation of reduced Preyssler acid. Gold nanoparticles (Au NPs) were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM), and particle size distribution (PSD) measurements. The synthesized Au NPs had a uniform hexagonal morphology and their size was about 17 nm. The catalytic performance of these NPs for photodegradation of methyl orange (MeO) was investigated in aqueous solution. UV-Vis studies showed that Au NPs can catalyze photodegradation of this azo dye. The pseudo-first-order rate constants were also calculated for this reaction.

  15. The jasmonate precursor, 12-oxo-phytodienoic acid, induces phytoalexin synthesis in Petroselinum crispum cell cultures.

    Dittrich, H; Kutchan, T M; Zenk, M H


    The pentacyclic biosynthetic precursor of jasmonic acid, 12-oxo-phytodienoic acid, was found to induce synthesis of the major flavonoid, apiin, in cell suspension cultures of Petroselinum crispum. The accumulation of apiin was preceded by an increase in the relative levels of poly (A)+ RNAs that code for the flavonoid biosynthetic enzymes phenylalanine ammonia lyase, 4-coumarate:CoA ligase and chalcone synthase, Poly (A)+ RNAs reached maximal levels at approximately 4-6 h after the addition of elicitor while flavonoids continued to accumulate in the cultures for at least 6 days. 12-Oxo-phytodienoic acid is the first pentacyclic precursor in the jasmonic acid biosynthetic chain which functions as a signal transducer for phytoalexin induction.

  16. Effect of amino acids on the repression of alkaline protease synthesis in haloalkaliphilic Nocardiopsis dassonvillei

    Amit K. Sharma


    Full Text Available A newly isolated salt-tolerant alkaliphilic actinomycete, Nocardiopsis dassonvillei strain OK-18 grows on mineral salts medium with glucose as carbon source. It also grows and produces protease with amino acids as sole carbon source. The synthesis of extracellular alkaline protease parallel to growth was repressible by substrate concentrations. The absolute production of the protease was delinked with growth under nutritional stress, as protease production was high, despite poor growth. When amino acids served as the sole source of carbon and nitrogen, the enzyme production was significantly controlled by the number of amino acids. Maximal protease production was achieved with proline, asparagine, tyrosine, alanine, methionine and valine as sole source of carbon and nitrogen in minimal medium. With the increasing number of different amino acids in the presence and absence of glucose, the protease production was synergistically lower as compared to complex medium.

  17. In vitro synthesis of the unit that links teichoic acid to peptidoglycan.

    Hancock, I; Baddiley, J


    The role of cytidine diphosphate (CDP)-glycerol in gram-positive bacteria whose walls lack poly(glycerol phosphate) was investigated. Membrane preparations from Staphylococcus aureus H, Bacillus subtilis W23, and Micrococcus sp. 2102 catalyzed the incorporation of glycerol phosphate residues from radioactive CDP-glycerol into a water-soluble polymer. In toluenized cells of Micrococcus sp. 2102, some of this product became linked to the wall. In each case, maximum incorporation of glycerol phosphate residues required the presence of the nucleotide precursors of wall teichoic acid and of uridine diphosphate-N-acetylglucosamine. In membrane preparations capable of synthesizing peptidoglycan, vancomycin caused a decrease in the incorporation of isotope from CDP-glycerol into polymer. Synthesis of the poly (glycerol phosphate) unit thus depended at an early stage on the concomitant synthesis of wall teichoic acid and later on the synthesis of peptidoglycan. It is concluded that CDP-glycerol is the biosynthetic precursor of the tri(glycerol phosphate) linkage unit between teichoic acid and peptidoglycan that has recently been characterized in S. aureus H.

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

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


    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.

  19. Ionic liquids as novel solvents for the synthesis of sugar fatty acid ester.

    Mai, Ngoc Lan; Ahn, Kihun; Bae, Sang Woo; Shin, Dong Woo; Morya, Vivek Kumar; Koo, Yoon-Mo


    Sugar fatty acid esters are bio-surfactants known for their non-toxic, non-ionic, and high biodegradability . With great emulsifying and conditioning effects, sugar fatty acids are widely used in the food, pharmaceutical, and cosmetic industries. Biosynthesis of sugar fatty acid esters has attracted growing attention in recent decades. In this study, the enzymatic synthesis of sugar fatty acid esters in ionic liquids was developed, optimized, and scaled up. Reaction parameters affecting the conversion yield of lipase-catalyzed synthesis of glucose laurate from glucose and vinyl laurate (i.e. temperature, vinyl laurate/glucose molar ratio, and enzyme loads) were optimized by response surface methodology (RSM). In addition, production was scaled up to 2.5 L, and recycling of enzyme and ionic liquids was investigated. The results showed that under optimal reaction conditions (66.86 °C, vinyl laurate/glucose molar ratio of 7.63, enzyme load of 73.33 g/L), an experimental conversion yield of 96.4% was obtained which is close to the optimal value predicted by RSM (97.16%). A similar conversion yield was maintained when the reaction was carried out at 2.5 L. Moreover, the enzymes and ionic liquids could be recycled and reused effectively for up to 10 cycles. The results indicate the feasibility of ionic liquids as novel solvents for the biosynthesis of sugar fatty acid esters.

  20. Synthesis and Application of a Novel Perfluorooctylated Citric Acid

    YANG Wei; QING Feng-Ling; MENG Wei-Dong


    A novel perfluorooctylated citric acid was synthesized successfully via allylation of triethyl citrate followed by perfluorooctylation, reduction and hydrolysis. The fabrics treated with this compound showed good oil repellent and moderate water repellent properties: the oil repellent rating and the water repellent score were 6 and 80 respectively.Even after 10 washing cycles, the repellent properties were kept at the same level. The finished fabrics also showed some wrinkle-resistant properties, and the dry wrinkle recovery angle was increased by 53° compared with untreated fabrics. The critical surface energy of the treated fabric surface was 20±1 mN/m. This multifunctional compound also showed good water solubility, which would be beneficial for the environmental protection.

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

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


    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.

  2. Synthesis and Insecticidal Activities of Novel Phthalic Acid Diamides

    闫涛; 李玉新; 李永强; 王多义; 陈伟; 刘卓; 李正名


    In order to discover novel insecticides with the new action mode on ryanodine receptor (RyR), a series of novel phthalic acid diamide derivatives were designed and synthesized. All compounds were characterized by 1H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that some title compounds exhibited excellent insecticidal activities against Mythimna separata, Spodoptera exigua, and Plutella xylostella. The title compound 3-nitro-N-cyclopropyl-N'-[2-methyl-4-(perfluoropropan-2-yl)phenyl]phthalamidte (4a) was more efficient against diamondback moths than the control (chlorantraniliprole). The effects of some title compounds on intracellular calcium of neurons from the Spodoptera exigua proved that the title compounds were RyR activators.

  3. Synthesis and cholinesterase inhibition of cativic acid derivatives.

    Alza, Natalia P; Richmond, Victoria; Baier, Carlos J; Freire, Eleonora; Baggio, Ricardo; Murray, Ana Paula


    Alzheimer's disease (AD) is a neurodegenerative disorder associated with memory impairment and cognitive deficit. Most of the drugs currently available for the treatment of AD are acetylcholinesterase (AChE) inhibitors. In a preliminary study, significant AChE inhibition was observed for the ethanolic extract of Grindelia ventanensis (IC₅₀=0.79 mg/mL). This result prompted us to isolate the active constituent, a normal labdane diterpenoid identified as 17-hydroxycativic acid (1), through a bioassay guided fractionation. Taking into account that 1 showed moderate inhibition of AChE (IC₅₀=21.1 μM), selectivity over butyrylcholinesterase (BChE) (IC₅₀=171.1 μM) and that it was easily obtained from the plant extract in a very good yield (0.15% w/w), we decided to prepare semisynthetic derivatives of this natural diterpenoid through simple structural modifications. A set of twenty new cativic acid derivatives (3-6) was prepared from 1 through transformations on the carboxylic group at C-15, introducing a C2-C6 linker and a tertiary amine group. They were tested for their inhibitory activity against AChE and BChE and some structure-activity relationships were outlined. The most active derivative was compound 3c, with an IC₅₀ value of 3.2 μM for AChE. Enzyme kinetic studies and docking modeling revealed that this inhibitor targeted both the catalytic active site and the peripheral anionic site of this enzyme. Furthermore, 3c showed significant inhibition of AChE activity in SH-SY5Y human neuroblastoma cells, and was non-cytotoxic.

  4. Fatty Acid Composition of Tobacco Seed Oil and Synthesis of Alkyd Resin

    MUKHTAR,Azam; ULLAH,Habib; MUKHTAR,Hamid


    The fatty acid composition of tobacco seed oil revealed that the oil is rich in unsaturated fatty acids, having linoleic acid (71.63%), oleic acid (13.46%) and palmitic acid (8.72%) as the most abundant unsaturated and saturated fatty acids respectively. So the tobacco oil was characterized as semi-drying type on the basis of fatty acid composition. The synthesis of alkyd resin was carried out by alcoholysis or monoglyceride process using an alkali refined tobacco seed oil, pentaerythritol, cis-1,2,3,6-tetrahydrophthalic anhydride along with lithium hydroxide as catalyst.The alkyd resin so prepared was found to be bright and of low color with high gloss. The drying and hardness properties and adhesion of the tobacco seed oil derived alkyd resin were also found a bit superior to those of other alkyd resins of the same oil length. In addition, the water and acid resistance of the said alkyd was also found comparable to the other alkyds.

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

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert


    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.

  6. Microwave-Assisted Synthesis of Poly(Aspartic Acid-Itaconic Acid) Copolymer and Its Characterization

    Zhang Yuling; Jiang Yijian; Hu Zhiguang; Wei Hanxiao; Guo Jun; Wang Jilong


    Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid (Asp) and itaconic acid (Ita) un-der microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itaconic acid and aspartic acid, catalyst type, catalyst and organic solvent content on copolymer yield, and the performance for inhibition of CaCO3 fouling were investigated. It was found that the product yield achieved a highest record of 95% when the amount of catalyst NaH2PO4was 0.012 mol, the amount of organic solvent propylene carbonate was 16 mL, the molar ratio of Asp/Ita was 3:1, the microwave output power was 1200 W and the irradiation time was 5.5 min. And the product performance for inhibition of calcium carbonate also reached a highest value of 94.38%. Structural characterization of the product showed that the product was the aspartic acid-itaconic acid copolymer.

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

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


    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.

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

    Madsen, U; Sløk, F A; Stensbøl, T B;


    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...

  9. Enhanced Cutinase-Catalyzed Hydrolysis of Polyethylene Terephthalate by Covalent Fusion to Hydrophobins

    Ribitsch, Doris; Herrero Acero, Enrique; Przylucka, Agnieszka; Zitzenbacher, Sabine; Marold, Annemarie; Gamerith, Caroline; Tscheließnig, Rupert; Jungbauer, Alois; Rennhofer, Harald; Lichtenegger, Helga; Amenitsch, Heinz; Bonazza, Klaus; Kubicek, Christian P.; Guebitz, Georg M.


    Cutinases have shown potential for hydrolysis of the recalcitrant synthetic polymer polyethylene terephthalate (PET). We have shown previously that the rate of this hydrolysis can be enhanced by the addition of hydrophobins, small fungal proteins that can alter the physicochemical properties of surfaces. Here we have investigated whether the PET-hydrolyzing activity of a bacterial cutinase from Thermobifida cellulosilytica (Thc_Cut1) would be further enhanced by fusion to one of three Trichoderma hydrophobins, i.e., the class II hydrophobins HFB4 and HFB7 and the pseudo-class I hydrophobin HFB9b. The fusion enzymes exhibited decreased kcat values on soluble substrates (p-nitrophenyl acetate and p-nitrophenyl butyrate) and strongly decreased the hydrophilicity of glass but caused only small changes in the hydrophobicity of PET. When the enzyme was fused to HFB4 or HFB7, the hydrolysis of PET was enhanced >16-fold over the level with the free enzyme, while a mixture of the enzyme and the hydrophobins led only to a 4-fold increase at most. Fusion with the non-class II hydrophobin HFB9b did not increase the rate of hydrolysis over that of the enzyme-hydrophobin mixture, but HFB9b performed best when PET was preincubated with the hydrophobins before enzyme treatment. The pattern of hydrolysis by the fusion enzymes differed from that of Thc_Cut1 as the concentration of the product mono(2-hydroxyethyl) terephthalate relative to that of the main product, terephthalic acid, increased. Small-angle X-ray scattering (SAXS) analysis revealed an increased scattering contrast of the fusion proteins over that of the free proteins, suggesting a change in conformation or enhanced protein aggregation. Our data show that the level of hydrolysis of PET by cutinase can be significantly increased by fusion to hydrophobins. The data further suggest that this likely involves binding of the hydrophobins to the cutinase and changes in the conformation of its active center. PMID:25795674

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

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


    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.

  11. Salicylic acid and PEG-contained polyanhydrides: synthesis, characterization, and in vitro salicylic acid release.

    Cai, Qixiang; Zhu, K J; Zhang, Jianxiang


    Poly [bi(o-carboxyphenyl)adipate-polyethylene glycol] anhydrides--P(BOCA-PEG)--polymeric drugs were synthesized and characterized by Fourier transformed infrared spectroscopy, NMR, DSC, gel permeation chromatography, etc. Salicylic acid loading efficiency of these polymers ranged from 43.5% to 71.3%, which was much higher than that of other polymeric drugs with salicylic acid. The in vitro release of salicylic acid from the polymers was carried out in buffer conditions with different pH values and and rat gastrointestinal contents. The results showed the release rate of salicylic acid increased with the increase of PEG content in the polymers and the increase of pH value of degradation buffer solution. The rat cecal contents also greatly promoted the release of salicylic acid. In 0.1M phosphate buffer solution at pH8.0, 37 degrees C containing 5% rat cecal contents, P(BOCA-PEG200)(80:20) had 15% salicylic acid released in 21 hr, indicating its potential use in colon-specific salicylic acid delivery.

  12. Synthesis of novel conjugates of a saccharide, amino acids, nucleobase and the evaluation of their cell compatibility

    Dan Yuan


    Full Text Available This article reports the synthesis of a novel type of conjugate of three fundamental biological build blocks (i.e., saccharide, amino acids, and nucleobase and their cell compatibility. The facile synthesis starts with the synthesis of nucleobase and saccharide derivatives, then uses solid-phase peptide synthesis (SPPS to build the peptide segment (Phe-Arg-Gly-Asp or naphthAla-Phe-Arg-Gly-Asp with fully protected groups, and later, an amidation reaction in liquid phase connects these three parts together. The overall yield of these multiple step synthesis is about 34%. Besides exhibiting excellent solubility, these conjugates of saccharide–amino acids–nucleobase (SAN, like the previously reported conjugates of nucleobase–amino acids–saccharide (NAS and nucleobase–saccharide–amino acids (NSA, are mammalian cell compatible.

  13. Synthesis and characterization of arsenate antimonic acid AAAc(1 : 1)

    WANG Xue-wen; CHEN Qi-yuan; YIN Zhou-lan; ZHANG Ping-min; WANG Yu-wen


    The AAAc(1 : 1) was synthesized in water by As2O3 and Sb2O3 with molar ratio of 1 : 1: AAAc(1 : 1)was characterized by Raman, IR, TG/DTG, DSC, XPS and XRD. The results show that there are four peaks to vsof As-OH, As-O-Sb, Sb-OH and Sb-O-Sb in Raman spectra of AAAc(1 : 1) at 100 - 1 000 cm-1. The solution of AAAc(1 : 1) was also titrated with KOH solution. The titration results show that AAAc(1 : 1) is a hexabasic acid with dissociation constants of k1 = 3.62 × 10-2 , k2 = 3.05 × 10-3 , k3 = 6. 43 × 10-6 , k4 = 9. 78 × 10-8 ,k5 = 1.32 × 10-11 , k6 =3.87 × 10-12. AAAc(1 : 1) has a good solubility and stability in water, its solid obtained by free volatilizing water from its solution under air at ambient temperature is amorphous. Chemical and thermal analyture of AsO ( OH )2-OH-Sb ( OH )4-O-Sb ( OH )4-OH-AsO ( OH )2 or As ( OH )3-O-Sb(OH)4-O-Sb(OH)4-O-As(OH)3 (isomerism) through experimental determination and geometry optimization.

  14. The effects of retinoic acid on immunoglobulin synthesis: Role of interleukin 6

    Ballow, M.; Xiang, Shunan; Wang, Weiping; Brodsky, L. [Children`s Hospital of Buffalo, NY (United States)]|[State Univ. of New York, Buffalo, NY (United States)


    Retinoic acid (RA) and its parent compound, retinol (ROH, vitamin A), have been recognized as important immunopotentiating agents. Previous studies from our laboratory have demonstrated that PA can augment formalin-treated Staphylococcus aureus (SAC) stimulated immunoglobulin (Ig) synthesis of cord blood mononuclear cells (CBMC). To determine the mechanism(s) by which RA modulates Ig synthesis, we studied the effects of RA on B cells and cytokine production. The addition of RA (10{sup -5} to 10{sup -10} M) to Epstein-Barr virus (EBV)-transformed B-cell clones derived from either adult or cord blood B cells augmented Ig secretion twofold. In contrast, cell proliferation was inhibited as measured by {sup 3}H-thymidine incorporation. We evaluated two cytokines known to be constitutively produced by EBV cell lines, IL-1 and IL-6. While RA had no effect on IL-1 production, IL-6 synthesis was greatly enhanced (20- to 45-fold), which was also reflected by an increase in steady-state mRNA levels for IL-6 but not TNF-{alpha} or TGF-{beta} on Northern blot analysis. Polyclonal rabbit anti-IL-6 antibodies were used to block the augmenting effects of RA on Ig synthesis of adenoidal B cells. RA-induced augmentation in IgG and IgA synthesis was blocked 58 and 29%, respectively, by anti-IL-6 antibodies. These studies suggest that the enhancing effects of RA on Ig synthesis are mediated, at least in part, by the autocrine or paracrine effects of IL-6 on B-cell differentiation. 37 refs., 5 figs.

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

    Robabeh Baharfar; Razieh Azimi


    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.

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

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


    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.

  17. Effect of Nitric Acid Concentrations on Synthesis and Stability of Maghemite Nanoparticles Suspension

    Irwan Nurdin


    Full Text Available Maghemite (γ-Fe2O3 nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD, transmission electron microscopy (TEM, alternating gradient magnetometry (AGM, thermogravimetric analysis (TGA, dynamic light scattering (DLS, and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.

  18. Effect of nitric acid concentrations on synthesis and stability of maghemite nanoparticles suspension.

    Nurdin, Irwan; Johan, Mohd Rafie; Yaacob, Iskandar Idris; Ang, Bee Chin


    Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.

  19. Rates of synthesis and degradation of ribosomal ribonucleic acid during differentiation of Dictyostelium discoideum.

    Mangiarotti, G; Altruda, F; Lodish, H F


    Synthesis of ribosomes and ribosomal ribonucleic acid (RNA) continued during differentiation of Dictyostelium discoideum concurrently with extensive turnover of ribosomes synthesized during both growth and developmental stages. We show here that the rate of synthesis of 26S and 17S ribosomal RNA during differentiation was less than 15% of that in growing cells, and by the time of sorocarp formation only about 25% of the cellular ribosomes had been synthesized during differentiation. Ribosomes synthesized during growth and differentiation were utilized in messenger RNA translation to the same extent; about 50% of each class were on polyribosomes. Ribosome degradation is apparently an all-or-nothing process, since virtually all 80S monosomes present in developing cells could be incorporated into polysomes when growth conditions were restored. By several criteria, ribosomes synthesized during growth and differentiation were functionally indistinguishable. Our data, together with previously published information on changes in the messenger RNA population during differentiation, indicate that synthesis of new ribosomes is not necessary for translation of developmentally regulated messenger RNA. We also establish that the overall rate of messenger RNA synthesis during differentiation is less than 15% of that in growing cells.

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

    Kovács, Viktória; Gondor, Orsolya K; Szalai, Gabriella; Darkó, Eva; Majláth, Imre; Janda, Tibor; Pál, Magda


    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.

  1. Compromised mitochondrial fatty acid synthesis in transgenic mice results in defective protein lipoylation and energy disequilibrium.

    Stuart Smith

    Full Text Available A mouse model with compromised mitochondrial fatty acid synthesis has been engineered in order to assess the role of this pathway in mitochondrial function and overall health. Reduction in the expression of mitochondrial malonyl CoA-acyl carrier protein transacylase, a key enzyme in the pathway encoded by the nuclear Mcat gene, was achieved to varying extents in all examined tissues employing tamoxifen-inducible Cre-lox technology. Although affected mice consumed more food than control animals, they failed to gain weight, were less physically active, suffered from loss of white adipose tissue, reduced muscle strength, kyphosis, alopecia, hypothermia and shortened lifespan. The Mcat-deficient phenotype is attributed primarily to reduced synthesis, in several tissues, of the octanoyl precursors required for the posttranslational lipoylation of pyruvate and α-ketoglutarate dehydrogenase complexes, resulting in diminished capacity of the citric acid cycle and disruption of energy metabolism. The presence of an alternative lipoylation pathway that utilizes exogenous free lipoate appears restricted to liver and alone is insufficient for preservation of normal energy metabolism. Thus, de novo synthesis of precursors for the protein lipoylation pathway plays a vital role in maintenance of mitochondrial function and overall vigor.

  2. 聚乳酸的合成方法%Synthesis of polylactic acid



    聚乳酸是一类具有优良生物相容性和可生物降解的高分子材料,被广泛应用于医用领域,受到越来越多的关注.聚乳酸的合成主要有两种方法: 丙交酯的开环聚合和乳酸直接缩聚.综述近年来聚乳酸合成研究的最新进展,介绍了聚乳酸聚合的两种高效方法-反应挤出法和直接-固相聚合法,并展望了聚乳酸合成研究的前景.%Polylactic acid (PLA) is a biocompatible and biodegradable polymer, thus it is widely used in the medical area and is much more attractive. There are two main methods to synthetizing PLA, ring-opening polymerization of lactide and condensation polymerization of lactic acid. In this paper, the process of the new research of the PLA synthesis was reviewed. Beside, the PLA synthesis methods of reactive extrusion and direct melting polycondensation were introduced, which are two high efficiency methods. Finally, the foreground of PLA synthesis was prospected.

  3. 76 FR 58248 - Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, In Part, of...


    ... International Trade Administration Polyethylene Terephthalate Film, Sheet and Strip From India: Rescission, In... (CVD) order on polyethylene terephthalate film, sheet and strip from India covering the period January... companies: Ester Industries Limited, Garware Polyester Ltd., Jindal Poly Films Limited of India,...

  4. 76 FR 47546 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...


    ... Strip from India, 67 FR 44175 (July 1, 2002) (PET Film India Order). On July 1, 2010, the Department... Duty Determination: Polyethylene Terephthalate Film, Sheet, and Strip (PET Film) From India, 67 FR... Determination: Polyethylene Terephthalate Film, Sheet, and Strip From India, 66 FR 65893 (December 21, 2001),...

  5. 77 FR 46687 - Polyethylene Terephthalate Film, Sheet, and Strip From India: Preliminary Results of Antidumping...


    ... Review, 73 FR 71601 (November 25, 2008); see also Certain Polyethylene Terephthalate Film, Sheet and... Republic of China: Final Results of Antidumping Duty Administrative Review and New Shipper Review, 73 FR...: Final Modification, 77 FR 8101 (February 14, 2012). \\52\\ See Polyethylene Terephthalate Film, Sheet,...

  6. 78 FR 60311 - Polyethylene Terephthalate Film, Sheet, and Strip From Brazil, China, and the United Arab...


    ... COMMISSION Polyethylene Terephthalate Film, Sheet, and Strip From Brazil, China, and the United Arab Emirates... order on polyethylene terephthalate (``PET'') film, sheet, and strip from Brazil, China, and the United..., China, and the United Arab Emirates (73 FR 66595). The Commission is conducting reviews to...

  7. 78 FR 79400 - Polyethylene Terephthalate Film, Sheet, and Strip From the People's Republic of China: Initiation...


    ..., sheet, and strip (``PET film'') from the People's Republic of China (``PRC'') meets the statutory and... Terephthalate Film, Sheet, and Strip from the People's Republic of China; A-570-924; Request for New Shipper... International Trade Administration Polyethylene Terephthalate Film, Sheet, and Strip From the People's...


    Kumari Santosh


    Full Text Available 4-chloro-3-nitrobenzoic acid was selected as nucleus structure having good antibacterial property. It was thought worthwhile to synthesize Schiff base derivatives of 4-chloro-3-nitrobenzoic acid in search of better antibacterial agents. The compounds were synthesized by first reducing nitro group in presence of Sn/HCl to 3-amino-4-chlorobenzoic acid, which on treatment with substituted benzaldehyde afforded the synthesis of the envisaged compounds. The synthesized compounds were purified and chemically characterized. They were screened for their antibacterial activity and result suggested that SKY-1, SKY-5 and SKY-8 were highly active against both Gram (+ and Gram(- bacteria like B.subtilis, S.aureus and E.coli whereas all are were found moderately to inactive against P.aeruginosa.

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

    Anna Pawełczyk


    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. Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway.

    Lovelock, Sarah L; Lloyd, Richard C; Turner, Nicholas J


    Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1 cB elimination mechanism.

  11. Nitrogen Deposition Via N+ Implantation:Implications for Primordial Amino Acids Synthesis Revisited

    WANG Wei; SHI Huaibin; WANG Xiangqin; YU Zengliang


    In this paper amino acids synthesis in aqueous solution induced by ion implantation,which was possibly ubiquitous on primitive Earth,is investigated.As a discharge using a graphite rod as the anode under a nitrogen atmosphere was performed against ammonia water,it was found that three kinds of amino acids were produced.They were glycine,serine and alanine.By introducing ion implantation into the carboxylate solution,ammonia and amino acids were also formed via nitrogen deposition/fixation.Another isotopic experiment showed that both OH and H radicals played a crucial role in the arc-discharge-promoted reactions in aqueous solution Therefore,we believe that the impact of ions in the original atmospheric conditions might have functioned as a promoter in the chemical origin and evolution of life.

  12. A plausible simultaneous synthesis of amino acids and simple peptides on the primordial Earth.

    Parker, Eric T; Zhou, Manshui; Burton, Aaron S; Glavin, Daniel P; Dworkin, Jason P; Krishnamurthy, Ramanarayanan; Fernández, Facundo M; Bada, Jeffrey L


    Following his seminal work in 1953, Stanley Miller conducted an experiment in 1958 to study the polymerization of amino acids under simulated early Earth conditions. In the experiment, Miller sparked a gas mixture of CH4, NH3, and H2O, while intermittently adding the plausible prebiotic condensing reagent cyanamide. For unknown reasons, an analysis of the samples was not reported. We analyzed the archived samples for amino acids, dipeptides, and diketopiperazines by liquid chromatography, ion mobility spectrometry, and mass spectrometry. A dozen amino acids, 10 glycine-containing dipeptides, and 3 glycine-containing diketopiperazines were detected. Miller's experiment was repeated and similar polymerization products were observed. Aqueous heating experiments indicate that Strecker synthesis intermediates play a key role in facilitating polymerization. These results highlight the potential importance of condensing reagents in generating diversity within the prebiotic chemical inventory.

  13. Parallel Synthesis of an Imidazole-4,5-dicarboxamide Library Bearing Amino Acid Esters and Alkanamines

    Rosanna Solinas


    Full Text Available The imidazole-4,5-dicarboxylic acid scaffold is readily derivatized with amino acid esters and alkanamines to afford compounds with intramolecularly hydrogen bonded conformations that mimic substituted purines and therefore are hypothesized to be potential inhibitors of kinases through competitive binding to the ATP site. In this work, a total of 126 dissymmetrically disubstituted imidazole-4,5-dicarboxamides with amino acid ester and alkanamide substituents were prepared by parallel synthesis. The library members were purified by column chromatography on silica gel and the purified compounds characterized by LC-MS with LC detection at 214 nm. A selection of the final compounds was also analyzed by 1H-NMR spectroscopy. The analytically pure final products have been submitted to the Molecular Library Small Molecule Repository (MLSMR for screening in the Molecular Library Screening Center Network (MLSCN as part of the NIH Roadmap.

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

    S Adhikari; P Banerji


    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.

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

    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: [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)


    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.

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

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


    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.

  17. Docosahexaenoic acid synthesis from alpha-linolenic acid is inhibited by diets high in polyunsaturated fatty acids.

    Gibson, R A; Neumann, M A; Lien, E L; Boyd, K A; Tu, W C


    The conversion of the plant-derived omega-3 (n-3) α-linolenic acid (ALA, 18:3n-3) to the long-chain eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) can be increased by ALA sufficient diets compared to ALA deficient diets. Diets containing ALA above an optimal level result in no further increase in DHA levels in animals and humans. The present study evaluates means of maximizing plasma DHA accumulation by systematically varying both linoleic acid (LA, 18:2n-6) and ALA dietary level. Weanling rats were fed one of 54 diets for three weeks. The diets varied in the percentage of energy (en%) of LA (0.07-17.1 en%) and ALA (0.02-12.1 en%) by manipulating both the fat content and the balance of vegetable oils. The peak of plasma phospholipid DHA (>8% total fatty acids) was attained as a result of feeding a narrow dietary range of 1-3 en% ALA and 1-2 en% LA but was suppressed to basal levels (∼2% total fatty acids) at dietary intakes of total polyunsaturated fatty acids (PUFA) above 3 en%. We conclude it is possible to enhance the DHA status of rats fed diets containing ALA as the only source of n-3 fatty acids but only when the level of dietary PUFA is low (<3 en%).

  18. Up-cycling of PET (polyethylene terephthalate) to the biodegradable plastic PHA (polyhydroxyalkanoate).

    Kenny, Shane T; Runic, Jasmina Nikodinovic; Kaminsky, Walter; Woods, Trevor; Babu, Ramesh P; Keely, Chris M; Blau, Werner; O'Connor, Kevin E


    The conversion of the petrochemical polymer polyethylene terephthalate (PET) to a biodegradable plastic polyhydroxyal-kanoate (PHA) is described here. PET was pyrolised at 450 degrees C resulting in the production of a solid, liquid, and gaseous fraction. The liquid and gaseous fractions were burnt for energy recovery, whereas the solid fraction terephthalic acid (TA) was used as the feedstock for bacterial production of PHA. Strains previously reported to grow on TA were unable to accumulate PHA. We therefore isolated bacteria from soil exposed to PET granules at a PET bottle processing plant From the 32 strains isolated, three strains capable of accumulation of medium chain length PHA (mclPHA) from TA as a sole source of carbon and energy were selected for further study. These isolates were identified using 16S rDNA techniques as P. putida (GO16), P. putida (GO19), and P. frederiksbergensis (GO23). P. putida GO16 and GO19 accumulate PHA composed predominantly of a 3-hydroxydecanoic acid monomer while P. frederiksbergensis GO23 accumulates 3-hydroxydecanoic acid as the predominant monomer with increased amounts of 3-hydroxydodecanoic acid and 3-hydroxydodecenoic acid compared to the other two strains. PHA was detected in all three strains when nitrogen depleted below detectable levels in the growth medium. Strains GO16 and GO19 accumulate PHA at a maximal rate of approximately 8.4 mg PHA/l/h for 12 h before the rate of PHA accumulation decreased dramatically. Strain GO23 accumulates PHA at a lower maximal rate of 4.4 mg PHA/l/h but there was no slow down in the rate of PHA accumulation over time. Each of the PHA polymers is a thermoplastic with the onset of thermal degradation occurring around 308 degrees C with the complete degradation occurring by 370 degrees C. The molecular weight ranged from 74 to 123 kDa. X-ray diffraction indicated crystallinity of the order of 18-31%. Thermal analysis shows a low glass transition (-53 degrees C) with a broad melting

  19. Synthesis of hydrogenised dimeric acid%氢化二聚酸的制备

    刘林学; 赵彬侠


    目的 研究开发氢化二聚酸合成方法及其性质、用途.方法 以国内已大量工业化生产的不饱和二聚酸为原料经催化加氢方法生产性能更优异的氢化二聚酸.结果 采用自行开发的鈀催化剂在170~220℃,1.5~2.5MPa即可顺利地进行加氢反应,8 h后反应基本完成,转化率大于98%,总收率95%.结论 该法所生产的氢化二聚酸酸值、碘值、皂化值、黏度与国外同类产品相近.%Aim To research the synthesis process of hydrogenised dimeric acid. Methods The title compound was synthesized from dimeric acid by hydrogenisation via catalysis. Results Pd/C is used as catalyst being stirred for 8 h at 170 ~220℃ ,1. 5 ~2. 5 Mpa, the conversion of dimeric acid is more than 98% , the total yield is 95%. Conclusion The process was mild and available for synthesis of hydrogenised dimeric acid. The performance index (acid value, iodine value, saponification value and viscocity) of hydrogenised dimeric acid achieved that of o-verseas similar products.

  20. Intestinal FXR-mediated FGF15 production contributes to diurnal control of hepatic bile acid synthesis in mice

    Stroeve, Johanna H. M.; Brufau, Gemma; Stellaard, Frans; Gonzalez, Frank J.; Staels, Bart; Kuipers, Folkert


    Hepatic bile acid synthesis is subject to complex modes of transcriptional control, in which the bile acid-activated nuclear receptor farnesoid X receptor (FXR) in liver and intestine-derived, FXR-controlled fibroblast growth factor 15 (Fgf15) are involved. The Fgf15 pathway is assumed to contribute

  1. Silica Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Quinoxalines at Room Temperature

    Khodabakhsh Niknam


    Full Text Available The reaction of 3-mercaptopropylsilica (MPS and chlorosulfonic acid in chloroform afforded silica bonded S-sulfonic acid (SBSSA, which was used as a catalyst for the room temperature synthesis of quinoxaline derivatives from 1,2-diamino compounds and 1,2-dicarbonyl compounds. The catalyst could be recycled and reused several times without any loss of efficiency.

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

    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 ...


    ZHANGYuehua; HUANGWenqiang; 等


    An improved method is developed by using strongly acidic cation exchange resin(001×1,H+ form) as a catalyst for the synthesis of diphenyl 1-(N-benzyloxycarbonyl-amino) alkanephosphonates and 1-(N-benzyloxycarbonylamino) alkanephenyl phosphinic acids in high yields.

  4. Synthesis and optimization ring opening of monoepoxide linoleic acid using p-toluenesulfonic acid.

    Salimon, Jumat; Abdullah, Bashar Mudhaffar; Yusop, Rahimi M; Salih, Nadia; Yousif, Emad


    Biolubricant base oils, 9,12-hydroxy-10,13-oleioxy-12-octadecanoic acid (HYOOA) was synthesized based on the esterification reaction of Monoepoxide linoleic acid 9(12)-10(13)-monoepoxy 12(9)-octadecanoic acid (MEOA) with oleic acid (OA) and catalyzed by p-Toluenesulfonic acid. The optimum conditions for the experiment using D-optimal design to obtain high yield% of 84.61, conversion% of 83.54 and lowest OOC% of 0.05 were predicted at OA/MEOA ratio of 0.2:1 (mol/mol), PTSA/MEOA ratio of 0.4:1 (mol/mol), reaction temperature at 110°C, and reaction time at 4.5 h. The FTIR peaks of HYOOA indicate the disappearance of the absorption band at 820 cm(-1), which belongs to the oxirane ring. (13)C and (1)H NMR spectra analyses confirmed the result of HYOOA with appearance carbon-ester (C = O) chemical shift at 174.1 ppm and at 4.06 ppm for (13)C and (1)H NMR respectively.

  5. Qualitative comparison of polyethylene terephthalate flakes from various collection systems in Germany.

    Snell, H; Nassour, A; Nelles, M


    In 2003, a deposit system for one-way packaging was introduced in Germany. Since that time, polyethylene terephthalate beverage packaging is collected through various collection systems, a deposit system, a reusable packaging system and the 'Green Dot' (the dual system) with the yellow bag. The manner of collection had a decisive influence on the quality of the generated recycled materials. The research at hand shows for the first time how the quality of polyethylene terephthalate flakes depends on the type of collection system. The results are based on a 14-year time frame, during which the quality of the polyethylene terephthalate flakes was examined using the different collection systems. The criterion used was the amount of contamination of polyethylene terephthalate flakes with various polymers, metals and other substances. Grain size and bulk density were also compared. The outcome shows that material from the deposit systems resulted in a better quality of polyethylene terephthalate (PET) flakes.

  6. A novel preparation of milk protein/polyethylene terephthalate fabric

    Zhou, J. F.; Zheng, D. D.; Zhong, L.; Zhang, F. X.; Zhang, G. X.


    In this work, -NH2 groups were introduced to polyethylene terephthalate (PET) fibers by nitration and reduction method, and then milk protein was grafted on the nitrated and reduced PET (NR PET) fibers by sucrose glycidyl ether crosslinking agent. FTIR suggested the milk protein was successfully grafted on PET fiber surface. SEM images showed a layer of substance covered on the PET fiber surface. DSC demonstrated an excellent thermal stability of milk protein/PET fiber. The moisture regain was improved by milk protein/PET fiber. Moreover, the crease recovery angle and stiffness were retained by the milk protein/PET fabric.

  7. Thermal Behavior of Poly(trimethylene-co-ethylene terephthalate)

    Yong XU; Sheng Rong YE; Jin Wen QIAN


    Poly (trimethylene-co-ethylene terephthalate) with various compositions of diol has been synthesized. The crystallization of copolyesters with high comonomer content was observed by both wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). It was found that the copolyesters become less crystallizable with the involvement of the comonomer,the crystals of crystallizable copolyesters come from PTT or PET homopolymers. The glass transition temperature (Tg) of the copolyester increases with increasing PET component in the copolyester, and the relationship between Tg and composition obey both Fox equation and additive law, the former is better in describing this relationship.

  8. Electron beam irradiation effects on poly(ethylene terephthalate)

    Burillo, G. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico, DF 04510 (Mexico)], E-mail:; Tenorio, L.; Bucio, E. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico, DF 04510 (Mexico); Adem, E. [Departamento de Fisica Experimental, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico, DF 04510 (Mexico); Lopez, G.P. [Department of Chemical and Nuclear Engineering, Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131 (United States)


    Changes in poly(ethylene terephthalate) subjected to electron beam irradiation at doses up to 15 MGy and dose rate of 1.65 MGy/h, were investigated by differential scanning calorimetry, molecular weight measurement, X-ray photoelectron spectroscopy, and scanning electron microscopy. Irradiated samples showed a decrease of molecular weight with a minimum at 5 MGy, which is attributed to chain scission of the macromolecules and then an increase at further doses due to branching and some degradation effect. Irradiation in air is not an important factor because the high dose rate of irradiation inhibits oxygen diffusion in the samples.


    LI Wei; TONG Gang; ZHOU Yiqin; QI Zongneng


    The Thermally Stimulated Current (TSC) spectra of a series of Sub-Tg annealed polyethylene terephthalate (PET) specimens have been measured. It is found that there is only one peak at 80℃ above room temperature, which related to the thermo-relaxation of frozen-in dipoles. The activation energy of such dipole motion has been calculated. The relation between the maximum current and the storage time can be explained by the free volume theory and agrees with the results from the excess thermodynamic properties. Compared with Differential Scanning Calorimeter (DSC) and tensile stress-strain method, TSC is a simpler and more sensitive method in studying Sub-Tg annealed polymers.

  10. Amino acids attached to 2'-amino-LNA: Synthesis of DNA mixmer oligonucleotides with increased duplex stability

    Johannsen, Marie Willaing; Wengel, Jesper; Wamberg, Michael Chr.;


    The synthesis of 2'-amino-LNA (locked nucleic acid) opens up exciting possibilities for modification of nucleic acids by conjugation to the 2'-nitrogen. Incorporation of unmodified and N-functionalized 2'-amino-LNA nucleotides improve duplex stability compared to unmodified DNA. 2'-Amino......-LNA nucleosides derivatized with amino acids have been synthesized and incorporated into DNA oligonucleotides. Following oligonucleotide synthesis, peptides have been added using solid phase peptide coupling chem. Modification of oligonucleotides with pos. charged residues greatly improves thermal stability....

  11. High-yield synthesis of bioactive ethyl cinnamate by enzymatic esterification of cinnamic acid.

    Wang, Yun; Zhang, Dong-Hao; Zhang, Jiang-Yan; Chen, Na; Zhi, Gao-Ying


    In this paper, Lipozyme TLIM-catalyzed synthesis of ethyl cinnamate through esterification of cinnamic acid with ethanol was studied. In order to increase the yield of ethyl cinnamate, several media, including acetone, isooctane, DMSO and solvent-free medium, were investigated in this reaction. The reaction showed a high yield by using isooctane as reaction medium, which was found to be much higher than the yields reported previously. Furthermore, several parameters such as shaking rate, water activity, reaction temperature, substrate molar ratio and enzyme loading had important influences on this reaction. For instance, when temperature increased from 10 to 50 °C, the initial reaction rate increased by 18 times and the yield of ethyl cinnamate increased by 6.2 times. Under the optimum conditions, lipase-catalyzed synthesis of ethyl cinnamate gave a maximum yield of 99%, which was of general interest for developing industrial processes for the preparation of ethyl cinnamate.

  12. Simple synthesis of luminescent CdSe quantum dots from ascorbic acid and selenium dioxide.

    Wang, Yilin; Yu, Meihua; Yang, Kun; Lu, Jianping; Chen, Linqing


    A simple, low-cost and convenient method was developed for the synthesis of highly luminescent CdSe quantum dots (QDs) in an aqueous medium. Compared with previous methods, this synthesis was carried out in one pot using ascorbic acid (C6H8O6) to replace NaBH4 or N2H4·H2O as a reductant, and selenium dioxide to replace selenium or its other hazardous, expensive and unstable compounds as a precursor. The mechanism of CdSe QDs formation was elucidated. The influence of various experimental variables, including refluxing time, Cd/MSA and Cd/Se molar ratios, on the luminescent properties of the QDs were systematically investigated. X-Ray powder diffraction and transmission electron microscopy characterization indicated that the QDs had a pure cubic zinc-blended structure with a spherical shape.

  13. One-step synthesis of boronic acid functionalized gold nanoclusters for photoluminescence sensing of dopamine

    Chen, Huide; Liu, Chunxiu; Xia, Yunsheng


    This study is the first to report one-step synthesis of boronic acid functionalized gold nanoclusters (AuNCs) using mixed ligands of 4-mercaptophenylboronic acid (MPBA) and glutathione. Furthermore, the emission color of the products can be fancily tuned from green to near-infrared by simply changing the proportion of the two stabilizers. In basic media, dopamine (DA) molecules themselves polymerize each other and form polydopamine with large amounts of cis-diol groups, which then react with boronic acid groups on the AuNC’s surface based on the formation of boronate esters. As a result, the photoluminescence of the AuNCs is well quenched by the electron transfer effect. Accordingly, DA molecules are assayed from 0.5 to 9 μM, and the detection limit is as low as 0.1 μM. The as-prepared AuNCs exhibit high selectivity; the existing biomolecules including various amino acids, ascorbic acid, uric acid, glucose, etc, do not interfere with the assay. The proposed method is successfully applied to the assay of DA in human serum, indicating its practical potential.

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

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


    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.


    Ling-ling Wang; Yi-xian Wu; Ri-wei Xu; Guan-ying Wu; Wan-tai Yang


    Poly(amino acid) has been widely utilized in drug delivery, tissue engineering and biomedical materials. Thebiomateriais based on poly(glutamic acid) are usually modified via copolymerization with other monomers such as L-asparticacid to improve the uncontrolled degradation rate. The ring-opening homo- and co-polymerization of y-benzyl-L-glutamateN-carboxyanhydride (BLG-NCA) and β-benzyl-L-aspartate N-carboxyanhydride (BLA-NCA) were carried out in solution byusing triethylamine (TEA) as initiator. The BLG-NCA homopolymerization could take place even at-30℃ and molecularweight of poly(γ-benzyl-L-glutamate) decreased with increasing polymerization temperature. The BLA-NCA polymerizationdid not occur at -10℃ and was needed to be carried out at 25℃ to improve the polymerization. Poly(γ-benzyl-L-glutamate)and poly(β-benzyl-L-aspartate) with unimodal molecular weigh distribution and weight average molecular weight (Mw) of32100 and 4000 could be obtained at 25℃. The copolymers of γ-benzyl L-glutamate and β-benzyl L-aspartate withunimodal molecular weight distribution and Mw ranging from 5600 to 24600 could be prepared. The useful copolymers ofpoly(L-glutamic acid-co-L-aspartic acid) were further prepared by removal of benzyl groups.

  16. Synthesis of cellulose by Acetobacter xylinum. VI. Growth on citric acid-cycle intermediates.



    Gromet-Elhanan, Zippora (The Hebrew University, Jerusalem, Israel) and Shlomo Hestrin. Synthesis of cellulose by Acetobacter xylinum. VI. Growth on citric acid-cycle intermediates. J. Bacteriol. 85:284-292. 1963.-Acetobacter xylinum could be made to grow on ethanol, acetate, succinate, or l-malate. The growth was accompanied by formation of opaque leathery pellicles on the surface of the growth medium. These pellicles were identified as cellulose on the basis of their chemical properties, solubility behavior, and infrared absorption spectra. Washed-cell suspensions prepared from cultures grown on ethanol or the organic acids, in contrast to washed sugar-grown cells, were able to transform citric-cycle intermediates into cellulose. The variations in the substrate spectrum of cellulose synthesis between sugar-grown cells and organic acids-grown cells were found to be correlated with differences in the oxidative capacity of the cells. The significance of the findings that A. xylinum could be made to grow on ethanol on complex as well as synthetic media is discussed from the viewpoint of the whole pattern of Acetobacter classification.

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

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


    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.

  18. Synthesis, isolation and characterization of methyl levulinate from cellulose catalyzed by extremely low concentration acid

    Hui; Li; Lincai; Peng; Lu; Lin; Keli; Chen; Heng; Zhang


    A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were developed in this study.Effects of different process variables towards the catalytic performance were performed as a function of reaction time.The results indicated that sulfuric acid concentration,temperature and initial cellulose concentration had significant effects on the synthesis of methyl levulinate.An optimized yield of around 50%was achieved at 210 C for 120 min with sulfuric acid concentration of 0.01 mol/L and initial cellulose concentration below 100 g/L.The resulting product mixture was isolated by a distillation technique that combines an atmospheric distillation with a vacuum distillation where n-dodecane was added to help distill the heavy fraction.The light fraction including mainly methanol could be reused as the reaction medium without any substantial change in the yield of methyl levulinate.The chemical composition and structural of lower heavy fraction were characterized by GC/MS,FTIR,1H-NMR and13C-NMR techniques.Methyl levulinate was found to be a major ingredient of lower heavy fraction with the content over 96%.This pathway is efficient,environmentally benign and economical for the production of pure levulinate esters from cellulose.

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

    Hajar Zamani


    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.

  20. Aliphatic amidase of Rhodococcus rhodochrous PA-34: Purification, characterization and application in synthesis of acrylic acid.

    Thakur, Neerja; Kumar, Vijay; Sharma, Nirmal Kant; Thakur, Shikha; Bhalla, Tek Chand


    An intracellular aliphatic amide degrading inducible amidase produced by Rhodococcus rhodochrous PA-34 was characterized and acrylic acid synthesis from acrylamide was carried out using whole cell amidase. A bioprocess was developed at 50 ml fed batch reaction using 400 mM acrylamide feeding at an interval of 30 min resulted in the production of 4 g acrylic acid with volumetric and catalytic productivity of 80 g/l and 19 g/g/h respectively. The amidase of this organism had molecular weight of 40 kDa and was purified to 8.5 fold with 8% yield. This enzyme was active within the temperature range of 30 to 60 °C, with optimum temperature 45 °C and pH 7.5. The Vmax, Km, and kcat of purified amidase were calculated as 250 U/mg protein, 4.5 mM, and 166 sec-1 for acrylamide. The enzyme showed tolerance to metal chelating agent (EDTA) and was strongly inhibited by heavy metal ions Hg2+, Ag2+, Cu2+ and Co2+. R. rhodochrous PA-34 amidase preferentially hydrolyzed small aliphatic toxic amide such as acrylamide. Thus, the amidase of R. rhodochrous PA-34 is promising biocatalyst for the synthesis of industrially important acids and biodegradation of toxic amides.