An environmentally friendly, chemoselective, and efficient protocol for the preparation of coumarin derivatives by Pechman condensation reaction using new and reusable heterogeneous Lewis acid catalyst polystyrene-supported GaCl3
作者:Ali Rahmatpour、Sara Mohammadian
DOI:10.1016/j.crci.2013.01.006
日期:2013.3
Résumé An environmentally benign Pechman protocol for the one-pot synthesis of 4-substituted coumarins through the condensation reactions of phenol substrates with β-ketoesters using polystyrene-supported GaCl3 (PS–GaCl3) as a highly active and reusable solid Lewis acid catalyst under mild and heterogeneous conditions in good to excellent yields is described. This new protocol is easy, simple, cost-effective, chemoselective, and in addition has the advantages of easy availability, stability, reusability and eco-friendly character of the catalyst, high to excellent yields, simple experimental and work-up procedure.
摘要
描述了一种环境友好的Pechman法,通过苯酚底物与β-酮酯的缩合反应,利用聚苯乙烯支持的氯化镓(PS–GaCl3)作为高效且可重复使用的固体路易斯酸催化剂,在温和和异相条件下进行4-取代香豆素的一锅合成,反应产率良好至优异。该新方法简单易行、经济实惠、选择性强,并且具有催化剂易获得、稳定性好、可重复使用和环保特性,反应产率高至优异,实验和后处理过程简单。