已经详细研究了2-氨基-2-脱氧甘露糖醛糖与异氰酸芳基酯的反应,并获得了脲和杂环衍生物。糖基呋喃并[ 2,1- d ]咪唑烷基-2-酮62的形成机理现已变得可见,而先前的报道和涉及该主题的经典文献提出了反应产物的替代结构。该反应是pH依赖性的,在酸性pH值下仅能平稳地获得呋喃酮类自行车,而在中性或碱性介质中,可以分离出5-羟基咪唑啉-2-酮衍生物66。这些单环结构似乎是反应的真正中间体,并且在适当的条件下,可以独家转化为相应的顺式融合的五元环系统。同样,还制备了第一个顺式融合的吡喃并[ 2,1- d ]咪唑烷基-2-酮75。
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.
A facile access to ureido sugars. Synthesis of urea-bridged β-cyclodextrins
作者:Inés Maya、Óscar López、Susana Maza、José G. Fernández-Bolaños、José Fuentes
DOI:10.1016/j.tetlet.2003.09.140
日期:2003.11
The preparation of a urea-bridged beta-cyclodextrin dimer and of a 6-monodeoxy-6-mono[3-(beta-D-glucopyranos-2-yl)ureido]-beta-cyclodextrin has been developed, using triphosgene as the isocyanation agent in an aqueous two-phase system. Per-O-acetylated beta-D-gluco and mannopyranosylamines and 2-amino-2-deoxy-alpha- and beta-D-glucose were also transformed into the corresponding isocyanates and converted in situ into ureas by coupling with aromatic and aliphatic amines. (C) 2003 Elsevier Ltd. All rights reserved.