Synthese einer tetrasaccharideinheit des kapselpolysaccharides von Streptococcus pneumoniae Typ 9V
作者:Hans Paulsen、Bernd Helpap
DOI:10.1016/0008-6215(89)84034-0
日期:1989.3
In the synthesis of 8-methoxycarbonyloctyl O-(alpha-D-galactopyranosyl)-(1----3)-O-(2-acetamido-2-deoxy-beta-D- mannopyranosyl)-(1----4)-O-(beta-D-glucopyranosyl)-(1----4)-alpha-D- glucopyranoside, which represents a component of the capsular polysaccharide of Streptococcus pneumoniae type 9V, the key step was the coupling of alpha-D-Galp-(1----3)-beta-D-ManpNAc-(1----4)-D-Glc as glycosyl donor with
A mild and general procedure for the synthesis of alpha-thioglycosides from glycopyranoses is described. The method involves the treatment of pyranose reductive sugar with sodium hydride, carbon disulfide, and p-nitrobenzoyl chloride, as a key step, to yield p-nitrobenzoyl-alpha-D-thioglycopyranose intermediates with high stereoselectivity, in a one-pot-two-step process. The interest of the strategy highlights a direct stereoselective access to ether-protected 1-thiol-alpha-D-glycopyranose derivatives (Gal, Glc, and Man) from pyranoses in the absence of anomeric 'Lewis acid' promoters. (c) 2006 Elsevier Ltd. All rights reserved.
PAULSEN, HANS;HELPAP, BERND, CARBOHYDR. RES., 186,(1989) N, C. 189-205