New synthetic approaches to sugar ureas. Access to ureido-β-cyclodextrins
作者:Óscar López、Susana Maza、Inés Maya、José Fuentes、José G. Fernández-Bolaños
DOI:10.1016/j.tet.2005.07.041
日期:2005.9
An efficient method for the preparation of urea-bridged cyclodextrins using triphosgene in the isocyanation step in an aqueous two-phase system is reported. Per-O-acetylated glycopyranosylamines and 2-amino-2-deoxy-alpha and beta-D-glucose were also transformed into the corresponding isocyanates using either an aqueous two-phase or an anhydrous dichloromethane medium, and converted in situ into ureas. An alternative method for the preparation of sugar-derived ureas consisting of desulfurization of sugar thioureas with mercury oxide is also presented. (c) 2005 Elsevier Ltd. All rights reserved.