نتایج جستجو برای: unsaturated ester
تعداد نتایج: 53007 فیلتر نتایج به سال:
A general and simple procedure to access chiral β'-amino-α,β-enones, in seven steps, from an α,β unsaturated ester has been described. The use of a Horner-Wadsworth-Emmons reaction as a key step for generating the β'-amino-α,β-enones, permits access to a range of substrates under mild conditions and in moderate to high yield.
Highly enantioselective NHC-organocatalyzed synthesis of functionalized cyclopentenes proceeding via α,β-unsaturated acyl azolium intermediates is reported. The organocascade reaction of modified enals with malonic ester derivatives having a γ-benzoyl group involves the Michael-intramolecular aldol-β-lactonization-decarboxylation sequence to deliver cyclopentenes in good yields and excellent ee...
deprotection of phosphate, phosphate, and sulfite esters by silica chloride is described. silica chloride is a mild, selective, and effective reagent for cleavage of benzyl and t-butyl esters of the above compounds.
Sixteen delta 4-uronate monosaccharides were chemically synthesized. Their carboxy group was protected as a methyl or benzyl ester, the anomeric hydroxyl group as a benzyl glycoside and the 2 and 3 hydroxyl groups were protected with different substitution patterns as both ester and ether derivatives. Disaccharides containing delta 4-uronates were prepared from heparin layses. Their carboxy gro...
Unsaturated polyester and epoxy vinyl ester resins have broad utility in composite applications. Today’s commercially available premium thermal performance vinyl ester resins are derived from novolac epoxies and methacrylic acid. These products combine low viscosity with shelf stable, yet fast curing properties, and enable fabricators to manufacture composite parts with rapid throughput for dem...
The Phlomis bracteosa oil constituents of methyl ester derivatives of fatty acids were analyzed using Gas Chromatography coupled to mass spectrometer. The results obtained containing the saturated as well as unsaturated fatty acids of P. bracteosa oils. A total of 18 different components were identified and quantified. Methyl ester of octadecadienoic acid was found in high concentration 6.88 %,...
Several cis-unsaturated fatty acids such as oleic, linoleic, linolenic, eicosapentaenoic, and docosahexaenoic acids added directly to intact human platelets greatly enhance protein kinase C activation as judged by the phosphorylation of its specific endogenous substrate, a 47-kDa protein. This enhancement absolutely requires the presence of a membrane-permeant diacylglycerol, 1,2-dioctanoylglyc...
A computational study of the aqueous pK(a) of some saturated and unsaturated cyclic and linear esters and ketones was carried out at the DFT-B3LYP 6-31++G(2df,2pd), CBS-Q, and G2 levels, with the integral equation formalism polarizable continuum model for solvation, using a proton exchange mechanism. The influence of unsaturation, position of the double bond, and cyclization were studied. The c...
The core objective of this study was to investigate the physicochemical characteristics and fatty acid composition oils sunflower, olive, virgin coconut ginger oils, as well separation their unsaturated acids. data indicated a significant variation in properties (acid, saponification, ester, iodine values) among oils. Transesterification process carried out at molar ratio 1:7:0.1 oil: methanol:...
In this research, an attempt was made to improve the brittle nature of Unsaturated Polyester (UP) polymer which cannot undergo plastic deformation be improved become more resilient by adding Thermoset Vinyl Ester and Methyl Methacrylate (MMA). To show change in toughness polyester material, a test is carried out provide tensile load flexural until material breaks This work reports successful fa...
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