Candida antarctica lipase A in the dynamic resolution of novel furylbenzotiazol-based cyanohydrin acetates
摘要:
A series of novel (R)-furylbenzotiazol-based cyanohydrin acetates were prepared in over 90% isolated yields from the corresponding furancarbaldehydes. The one-pot method combines a basic resin to produce hydrogen cyanide from acetone cyanohydrin, an equilibrium between the formation and decomposition of furylbenzotiazol-based cyanohydrins and the unique enantioselectivity of Candida antarctica lipase A, allowing the acylation of (R)-cyanohydrins in the presence of vinyl acetate in anhydrous acetonitrile. (C) 2003 Elsevier Science Ltd. All rights reserved.
for transamidation of thioamides by N−C(S) transacylation is reported. This process exploits the concept of site-selective N-tert-butoxycarbonyl activation, resulting in ground-state-destabilization of thioamides. The study establishes a powerful direction to the development of new molecules in chemistry and biology by rational modification of nN→π*C=S resonance of the thioamide bond.
报道了第一种通过 NC(S) 转酰基作用对硫代酰胺进行转酰胺基作用的通用、温和且高度化学选择性的方法。该过程利用了位点选择性 N-叔丁氧羰基活化的概念,导致硫代酰胺的基态不稳定。该研究通过对硫代酰胺键的n N →π* C=S共振进行合理修饰,为化学和生物学新分子的发展奠定了有力的方向。
Jagodzinski, Tadeusz S.; Dziembowska, Teresa M.; Szczodrowska, Barbara, Bulletin des Societes Chimiques Belges, 1989, vol. 98, # 5, p. 327 - 338
作者:Jagodzinski, Tadeusz S.、Dziembowska, Teresa M.、Szczodrowska, Barbara
DOI:——
日期:——
CaL-B a highly selective biocatalyst for the kinetic resolution of furylbenzthiazole-2-yl-ethanols and acetates
作者:László Csaba Bencze、Csaba Paizs、Monica Ioana Toşa、Maria Trif、Florin Dan Irimie
DOI:10.1016/j.tetasy.2010.06.010
日期:2010.8
A highly stereoselective enzymatic kinetic resolution of novel various substituted racemic furylbenzthiazole-2-yl-ethanols and their acetates has been developed. Both processes, the enzymatic acylation of the racemic alcohols and the enzymatic methanolysis of racemic acetates yielded highly enantiomerically enriched (ee >98%) resolution product, when CaL-B was used as a biocatalyst in acetonitrile. The absolute configuration of the obtained (R)-(+)-1-(5-(4-chlorobenzo[d]thiazol-2-yl)furan-2-y1)ethanol was determined by a detailed H-1 NMR study of rac- and (+)-1-(5-(4-chlorobenzo[d]thiazol-2-yl)furan-2-yl)ethanol Mosher derivatives. (C) 2010 Elsevier Ltd. All rights reserved.
Aminolysis of aryl dithio-2-thiophenates and dithio-2-furoates in acetonitrile
作者:Hyuck Keun Oh、So Young Woo、Chul Ho Shin、Ikchoon Lee
The aminolyses of the title substrates with anilines and benzylamines are investigated in acetonitrile. A clean second-order kinetics is obtained with a first-order rate law in the amine concentration, which is uncomplicated by the fast proton transfer step. The large magnitude of rho(z) (rho(1g)) as well as rho(x) (rho(nuc)) together with relatively large positive p(xz) values is consistent with a stepwise mechanism in which thiophenolate ion expulsion from the intermediate is rate limiting. For the reactions of aryl dithio-2-thiophenates with benzylamines the magnitude of rho(x) and rho(z) values is relatively smaller suggesting that both the addition and expulsion of thiophenolate are partially rate determining. Relatively large secondary kinetic isotope effects, k(H)/k(D) greater than or equal to 1.7, with deuterated nucleophiles, support involvement a concurrent proton transfer to the departing thiophenolate ion in the transition state. (C) 1998 John Wiley & Sons, Inc.
JAGODZINSKI, TADEUSZ S.;DZIEMBOWSKA, TERESA M.;SZCZODROWSKA, BARBARA, BULL. SOC. CHIM. BELG., 98,(1989) N, C. 327-338
作者:JAGODZINSKI, TADEUSZ S.、DZIEMBOWSKA, TERESA M.、SZCZODROWSKA, BARBARA