Efficient, green and solvent-free synthesis of tetrasubstituted imidazoles using SbCl3/SiO2 as heterogeneous catalyst

Abstract

Antimony trichloride absorbed on silica gel (SbCl3/SiO2) efficiently catalyses the four-component cyclocondensation of 1,2-diketone, aldehyde, ammonium acetate, and primary amine under solvent-free conditions to afford the corresponding tetrasubstituted imidazoles in high yields. The main merit of this study is introducing a novel catalyst to successful synthesis of a wide range of 1,2,4,5-tetrasubstituted imidazoles for the first time. The proposed method involves features such as simplicity, generality, fairly good efficiency, and reusability of the catalyst. An overall and effective synthetic strategy for the preparation of 1,2,4,5-tetrasubstituted imidazoles is introduced in the presence of SbCl3.SiO2 as a green and heterogeneous catalyst under solvent-free conditions.