Efficient, green and solvent-free synthesis of tetrasubstituted imidazoles using SbCl/SiO as heterogeneous catalyst.

Antimony trichloride absorbed on silica gel (SbCl/SiO) 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. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]