First synthesis of a malarial prototype: a fully lipidated and phosphorylated GPI membrane anchor
作者:Jun Lu、K.N. Jayaprakash、Bert Fraser-Reid
DOI:10.1016/j.tetlet.2003.10.179
日期:2004.1
A strategy is described for syntheses of a fully lipidated and phosphorylated prototype of the GPI of Plasmodium falciparum, the causative agent of lethal cerebral, drug-resistant malaria. Orthoesters, prepared in four steps from d-mannose, and methyl α-d-glucopyranoside are the key starting materials. The latter furnishes the inositol moiety using Bender’s procedure, while the former gives the other
Various Lewis acids have been examined as agents which react with N-iodosuccinimide to release iodonium ion for activating n-pentenylorthoester (NPOE) donors, particularly for coupling to acceptors that have acid-labile protecting groups. Although many of the reagents do not tolerate cyclic acetals, (BF3Et2O)-Et-. does. However, the latter cleaves p-methoxybenzyl (PMB), making it possible to use this Lewis acid to simultaneously promote coupling of NPOEs and remove PMB groups. Of several transition metal salts investigated, ytterbium triflate is outstanding in its ability to promote NPOE Coupling With complete preservation of acid-labile protecting groups. (C) 2002 Elsevier Science Ltd. All rights reserved.