One-pot synthesis of 2,4,5-tri-substituted and 1,2,4,5- tetra-substituted imidazoles catalyzed by poly (4-vinylpyridinium tribromide) (P.V.P.Br3) or citric acid

An efficient, one-pot method for preparation of tri and tetra-substituted imidazoles by condensation of benzil, aldehydes, and ammonium acetate or primary amine in the presence of a catalytic amount of citric acid or poly(4-vinylpyridinium tribromide) (P.V.P.Br3) under solvent-free conditions is reported. The remarkable advantages of this method are the inexpensive green catalyst, mild reaction conditions, simple procedures, and excellent yields of products.

Poly(4-vinylpyridinium tribromide)  Citric acid  Benzil  Ammonium acetate  Aromatic aldehydes