Efficient synthesis of aryloylamido coumarins derivatives via three-component coupling of 4-hydroxycoumarin, aryl glyoxal, and amides catalyzed by ZnO nanoparticles

Modern synthetic design demands high efficiency in terms of minimization of synthetic steps together with maximization of complexity [1]. One of the ways to fulfill these goals is the development and use of multicomponent reactions which consist of several simultaneous bond-forming reactions and allow the high efficient synthesis of complex molecules starting from simple substrates in a One-Pot manner [2].Coumarin and chromene and their derivatives have attracted considerable attention from organic and medicinal chemists for many years as a large number of natural products contain this heterocyclic nucleus. They are widely used as additives in food, perfumes, cosmetics, pharmaceuticals and optical brighteners and dispersed fluorescent and laser dyes. Thus the synthesis of derivatives of this nucleus is of much interest [3].We herein describe a practical and inexpensive method for the preparation of aryloylamido coumarins derivatives via a three-component condensation reaction between 4-hydroxycoumarin, aryl glyoxal, and amides or in the presence of ZnO nanoparticles as catalyst under thermal and solvent-free conditions.