共查询到19条相似文献,搜索用时 871 毫秒
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以β-环糊精为原料,经对甲苯磺酰化、叠氮化、还原氨基后,再与Boc保护的脯氨酸进行肽键缩合和脱Boc保护基,合成了单-6-脯氨酸-β-环糊精,其结构经1H NMR表征. 相似文献
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对α-氨基-β-酮酸酯(β-含氧二肽)的合成进行了探讨.以Boc保护的(L)-缬氨酸及(L)-异亮氨酸为原料,分别与(D,L)-苏氨酸甲酯盐酸盐进行偶合,再用Dess-Martin试剂(DMP)氧化,分别以48%和38%的总收率得到相应的氨基酮酸酯二肽化合物. 相似文献
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氨基磺酸催化剂在有机合成中的应用 总被引:6,自引:0,他引:6
综述了近年来氨基磺酸作为一种绿色催化剂在有机合成中的应用,主要包括酯化与酯交换、基团保护、氮杂Diels-Alder、重排、取代及缩合等反应。参考文献58篇。 相似文献
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Yoshimoto Abe Tetsushi Sekiguchi Takahisha Misono 《Journal of polymer science. Part A, Polymer chemistry》1984,22(3):761-767
The condensation of silicic acid butyl esters was investigated by gel permeation chromatographic (GPC) analysis. The results revealed that the condensation was greatly dependent on a degree of esterification of the esters. The ester with the lowest degree of esterification underwent condensation to form a highly polymerized ester. It was found that fibers could be drawn from the ester solution before gelation. 相似文献
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新型查尔酮类化合物的合成及其生物活性研究 总被引:12,自引:0,他引:12
以3,5-二羟基苯甲酸为原料, 分别经酯化、甲氧甲基保护或甲基化、酰肼化、氧化、醛酮缩合、脱保护基、O-法呢基化或O-异戊烯基化等步骤, 以5.6%~46%的总收率合成了8个未见文献报道的查尔酮类化合物1a~1h, 产物通过1H NMR, 13C NMR, IR, MS进行了结构确证. 对所合成的目标化合物在3个标准活性筛选模型中进行了生物活性试验, 结果表明化合物1b在组织蛋白酶B (CAT-B)模型、化合物1e在细胞分离周期基因25表达的蛋白磷酸酶(CDC25)模型中表现出良好的活性. 相似文献
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This study reports evidence for catalytic deoxygenation of alkanols, alkanals, and alkanediols on dispersed Cu clusters with minimal use of external H(2) and with the concurrent formation of new C-C and C-O bonds. These catalysts selectively remove O-atoms from these oxygenates as CO or CO(2) through decarbonylation or decarboxylation routes, respectively, that use C-atoms present within reactants or as H(2)O using H(2) added or formed in situ from CO/H(2)O mixtures via water-gas shift. Cu catalysts fully convert 1,3-propanediol to equilibrated propanol-propanal intermediates that subsequently form larger oxygenates via aldol-type condensation and esterification routes without detectable involvement of the oxide supports. Propanal-propanol-H(2) equilibration is mediated by their chemisorption and interconversion at surfaces via C-H and O-H activation and propoxide intermediates. The kinetic effects of H(2), propanal, and propanol pressures on turnover rates, taken together with measured selectivities and the established chemical events for base-catalyzed condensation and esterification reactions, indicate that both reactions involve kinetically relevant bimolecular steps in which propoxide species, acting as the base, abstract the α-hydrogen in adsorbed propanal (condensation) or attack the electrophilic C-atom at its carbonyl group (esterification). These weakly held basic alkoxides render Cu surfaces able to mediate C-C and C-O formation reactions typically catalyzed by basic sites inherent in the catalyst, instead of provided by coadsorbed organic moieties. Turnover rates for condensation and esterification reactions decrease with increasing Cu dispersion, because low-coordination corner and edge atoms prevalent on small clusters stabilize adsorbed intermediates and increase the activation barriers for the bimolecular kinetically relevant steps required for both reactions. 相似文献
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Russian Journal of General Chemistry - Six benzenesulfonylhydrazone derivatives of methyl dehydroabietate are synthesized via esterification, benzylic oxidation, condensation with hydrazine... 相似文献
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Thomas Glonek John R. Van Wazer Terrell C. Myers 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):137-150
Abstract Carbodiimide-mediated phosphorylations carried out with ortho-, pyro-, trimeta-, tetrameta-, and long-chain polyphosphoric acids dissolved in various alcohols, with and without an excess of tri-n-butylamine at 27° were found to consist of complicated reaction sequences involving various phosphoric acids, then esters and complexes formed between the carbodiimide and these acids or esters. In the case of the condensation of orthophosphoric acid, the process of stepwise esterification is seen to compete with the process of condensation to form condensed phosphoric acids and their esters. In general, esterification as opposed to condensation is promoted by (a) increased acidity, (b) smaller size, and (c) increased concentration of the alcohol, as well as by (d) increased concentration of dissociable protons in the solution. 31P chemical-shift data are given for ortho, chain, and ring phosphoric acids and their esters dissolved in the corresponding alcohol. Typical kinetic curves and the distribution of products obtained upon the cessation of condensation are also presented. 相似文献
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GUOHui ZOUWu-xin JIQi MAYu-xin MENGJi-ben 《高等学校化学研究》2005,21(4):447-451
Facile direct esterification reactions between 2‘, 3‘-O-isopropylidene-nucleosides and Fmoc- or trityl-protected amino acids via N, N-dicyclohexyl-carbodiimide(DCC) mediated condensation are described. These reactions offer a mild and convenient method to synthesize aminoacylated nucleoside derivatives. 相似文献