Synthesis, characterization and antimicrobial activity of 1,3,4-oxadiazole bearing 1H-benzimidazole derivatives

Abstract

2-(Phenoxymethyl)-1H-benzimidazole (3) obtained by acidic condensation of o-phenylene diamine with phenoxyacetic acid, was reacted with ethyl chloroacetate under anhydrous condition to get ethyl [2-(phenoxymethyl)-1H-benzimidazol-1-yl]acetate (4). The ethyl [2-(phenoxymethyl)-1H-benzimidazol-1-yl]acetate (4) on treatment hydrazine hydrate gave 2-[2-(phenoxymethyl)-1Hbenzimidazol-1-yl]acetohydrazide (5). The acid hydrazide group of 5 was cyclocondensed with various aromatic acids in presence of phosphorous oxychloride to get the titled compounds ( 6a–p ). The structures of all the compounds were established on the basis of elemental and spectral analysis. The synthesized compounds were evaluated for their antimicrobial activity. The compound 6d , 6f , 6h and 6d , 6h and 6I a is most active compounds against Escherichia coli and Staphylococcus aureus respectively. The compound 6d , 6f and 6l is most active against Candida albicans and Aspergillus flavus .