SONICATED ASSISTED SYNTHESIS OF BENZIMIDAZOLES, BENZOXAZOLES AND BENZOTHIAZOLES IN AQUEOUS MEDIA

ABSTRACT Ammonium nickel sulphate [(NH 4 ) 2 SO 4 .NiSO 4 .6H 2 O] was found as a new catalyst to synthesis 2-aryl benzimidazole, 2-aryl benzothiazole and 2-aryl benzoxazole in aqueous media under sonication irradiation. The procedure is an eco-friendly, efficient and provides simple workup and good yield. Keywords : - Benzimidazole, benzothiazole, benzoxazole, aqueous media, sonication, ammonium nickel sulphate. e-mail: snthore@rediffmail.com INTRODUCTION The benzimidazoles, benzoxazole and benzthaizoles are an important heterocyclic nucleus which has been widely used in medicinal chemistry 1,2 . These heterocycles are an important pharmacophore 3,4 in drug discovery and good intermediate 5 in synthesis of many important organic compounds. These heterocycles shows different pharmacological properties such as antibacterial 6 , antiviral 7 , antifugal 8 , anticancer 9 , anticonvulsant 10 and immunosuppressant 11 .These heterocycles can be prepared by condensing carboxylic acid 12 , acid chloride