A simple and efficient one-pot synthesis of novel benzimidazo[1,2-a]- chromeno[4,3-d] pyrimidinones catalyzed by [Et3NH][HSO4]

Abstract

A simple and efficient one-pot synthesis of novel polyheterocyclic benzimidazo[1,2-<em>a</em>]- chromeno[4,3-<em>d</em>]pyrimidinones <strong>4</strong> <em>via</em> a three-component condensation of 2-aminobenzimidazole <strong>1</strong>, aromatic aldehydes <strong>2</strong> and 4-hydroxy coumarin <strong>3</strong> catalyzed by Bronsted acid ionic liquid triethyl ammonium hydrogen sulphate [Et₃NH][HSO₄] under solvent-free conditions is reported. The main advantages of this protocol are short reaction time, easy work-up, operational simplicity, and excellent yields with high purity, without intervention of chromatography.