Ferric(III) nitrate supported on kieselguhr: a reusable and inexpensive catalyst for one-pot three-component synthesis of 2,4,5-trisubstituted imidazole derivatives under solvent-free conditions

Abstract

An efficient and green procedure for the synthesis of 2,4,5-trisubstituted-1H-imidazoles with various aldehydes, benzil, and ammonium acetate using a catalytic amount of ferric(III) nitrate supported on kieselguhr (Fe(NO3)3-Kie) as an active and low cost Lewis acid catalyst has been developed. The solid catalyst was easily separated from the reaction mixture and can be reused at least three times. This procedure has remarkable advantages compared to those reported in the previous literature, including high yields, cleaner reaction profiles, simple experimental and work-up procedures, and use of non-toxic or expensive catalyst. Moreover, this protocol is benign to the environment.