ONE-POT SYNTHESIS OF POLYSUBSTITUTED IMIDAZOLES FROM ARYLALDEHYDES IN WATER CATALYZED BY NHC USING MICROWAVE IRRADIATION

ABSTRACT A simple, high yielding synthesis of tri (3a-i) and tetrasubstituted (4a-g) imidazols from aldehydes is described. The cornerstone of this methodology involves the condensation of NH 4 OAc, substituted aldehydes, and benzoin, which is synthesized in situ from aldehydes catalyzed by N-heterocyclic carbine (NHC), under microwave irradiation in water to afford trisubstituted imidazoles (3a-i). If arylamine is added in the solution, tetrasubstituted imidazoles (4a-g) can be obtained. Lepidilines B and trifenagrel are also synthesized in high yield using this procedure. All the experiment deta are in agreement with the literature. Keywords: Trisubstituted imidazoles, tetrasubstituted imidazoles, microwave irradiation, Lepidilines B, Trifenagrel, N-heterocyclic carbine (NHC) INTRODUCTION Imidazole ring system is one of the most important substructures found in a large number of natural products and pharmacologically active compounds such as antiulcerative agent cimetidine 1 , the proton pump inhibitor omeprazole