Studies on syntheses of 1-alkyl/aralkyl-2-cinnamoylbenzimidazoles

Studies on syntheses of 1-alkyl/aralkyl-2-cinnamoylbenzimidazoles (5) have been reported. The title compounds have been synthesized by two different r outes, i) Condensation of 2-acetylbenzimidazole (3) with aromatic aldehydes yielding 2-cinnamoyl-benzimidazoles (4) followed by alkylation under Phase -Transfer catalyzed conditions and ii) Alkylation/aralkylation of 2-acetylb enzimidazole (3) under Phase-Transfer catalysed conditions giving (6) follo wed by condensation with aromatic aldehydes. 4a and 5a were oxidised with K MnO4 to the corresponding benzimidazole 2-carboxilic acids. The structure o f the products (5) are supported by their spectral and analytical data and by the identity of final products obtained in the two routes.