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[en] The 8 coumarin derivatives have been synthesized from 8 starting materials(2-hydroxy-benzophenone, 2,2'-dihydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-5-methylbenzophenone, 5-chloro-2-hydroxy-4-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-4'-dimethoxybenzophenone) with phenylacetic acid and Ac2O/TEA in acetone at reflux temperature. The ratio of o-hydroxybenzophenone, phenylacetic acid, Ac2O and TEA is 1:1:8:8 in acetone. Our results showed higher products yields of coumarin derivatives than Shama and Ray's method in previous papers. A new intermediate form was proposed to our mechanism of coumarin synthetic method
[en] A regioselective synthesis of pyridines by the addition of malonate anions to pyridine N-oxide derivatives, which have been activated by trifluoromethanesulfonic anhydride, is reported. The reaction selectively affords either 2- or 4-substituted pyridines in good yields. Graphical abstract: .
[en] For the purpose of development of effective synthetic process of CHMI, a series of experiments were preformed on the preparation of CHMAIE, the intermediate of CHMI. For the first step, CHMA was synthesized by dropwise mixing of cyclohexylamine with maleic anhydride in toluene and 98.2% of theoretical CHMA was obtained by precipitation at 10 .deg. C for 2 hours. The optimum reaction temperature of the esterification, preparation reaction of CHAMIE from CHMA, was 68 .deg. C, and equilibrium conversion at optimum temperature was 98.5%. Equilibrium reaction time decreased with reaction temperature, and 4 hours was taken to reach equilibrium at optimum reaction temperature. Toluene in the final reaction product could be recovered by vacuum distillation. The recovery of toluene was increased with distillation temperature and 98% of toluene could be recovered at 55 .deg. C
[en] This book introduces overseas chemical industry, which deals with General chemistry on economic view in the world and prospect and current situation over chemical industry, organic chemistry material on production and demand such as petrochemistry, Energy Supply, Ethylene, Propylene, BTX, Ethylene glycol, Acetaldehyde, Acetic acid, Vinyl Acetate Monomer, PVA, Acrylonitrile, Acrylic esters, Propylene oxide, Propylene Glycol, PPG, Phenol, Acetone, Isopropyl Alcohol, Butanol, Octanol, Methanol, Formalin, Caprolactam Cyclohexane, PTA/DMT, Polyisocyanate, MEK/MIBK, 1.4-BG/THF, Phthalic anhydride and Maleic Anhydride.
[en] In this first report it is described the synthesis, separation and purification of the 2-radioiodinated histamine- I-labelled histamine by a mixed anhydride reaction. About 75% incorporation of I-125, from Na125I, was achieved with a molecular ratio of 1:1 mixed anhydride:histamine. The radiochemical purity of the conjugate by TLC was > 99% and its theoretical specific activity, 3850 μCi/μg. Dissolved in ethanol and held at -20 degree centigree under darkness decomposition on storage didn't exceed 1% per month. (Author) 13 refs
[en] A radiation curable coating composition comprising (i) an adduct of a monoethylenically unsaturated carboxylic acid or hydroxy alkyl ester thereof with an anhydride containing at least 3 carbon atoms and selected from monoepoxides, lactones, and mixtures thereof, the adduct containing an average of at least 1 mole of anhydride per mol of hydroxy ester and an average of at least 2 moles of anhydride per mol of acid, (ii) a polyacrylate
[en] The objective of this study is to explore the effects of maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) on properties of polypropylene (PP)-based binder. The viscosity of feedstocks as well as properties of green parts, brown parts and sintered parts were investigated. Through the analysis of viscosity, the feedstock containing 8 vol% POE-g-MAH in binder was supposed to be more suitable for the injection molding. The impact absorbed energy at break increased with increasing POE-g-MAH content in binder while the bending strength decreased first and then increased. The introduction of POE-g-MAH improve the density distribution and increased the density of green parts. After debinding, most binder components were removed regardless of the POE-g-MAH content in binder. As for the parts after sintering, the carbon content decreased with an increase in POE-g-MAH content. The results suggest that POE-g-MAH act as a toughening agent as well as compatibilizer for PP-based binder/metal powder system. The mechanical properties of the green parts could be enhanced even after multiple injection and in addition the powder-binder separation trend could be decreased. (paper)
[en] The soluble NTPDase1 from L. pneumophila was crystallized in six crystal forms and the structure was solved using a sulfur SAD approach. Nucleoside triphosphate diphosphohydrolases (NTPDases) are a large class of nucleotidases that hydrolyze the (γ/β)- and (β/α)-anhydride bonds of nucleoside triphosphates and diphosphates, respectively. NTPDases are found throughout the eukaryotic domain. In addition, a very small number of members can be found in bacteria, most of which live as parasites of eukaryotic hosts. NTPDases of intracellular and extracellular parasites are emerging as important regulators for the survival of the parasite. To deepen the knowledge of the structure and function of this enzyme class, recombinant production of the NTPDase1 from the bacterium Legionella pneumophila has been established. The protein could be crystallized in six crystal forms, of which one has been described previously. The crystals diffracted to resolutions of between 1.4 and 2.5 Å. Experimental phases determined by a sulfur SAD experiment using an orthorhombic crystal form produced an interpretable electron-density map