SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF SOME NEWER BENZIMIDAZOLE DERIVATIVES BY MANNICH REACTION

O-phenylenediamine and salicylic acid were used for the synthesis of 2-(1-(substituted phenylamino) methyl-1H benzo[d] imidazol-2-yl) phenol (2a-2h) derivatives by using various substituted aniline. In the first step, reaction of o-phenylenediamine and salicylic acid yielded 2-(1H-benzo[d]imidazol-2-yl) phenol (1), which on Mannich reaction with substituted aniline gave compounds (2a-2h). The structures of these compounds were characterized by IR, 1H NMR, mass spectral data and elemental analysis. Each analogue was tested in vitro for various types of pharmacological activity of this class of drugs including antibacterial, antifungal and anthelmintic activity. Among the synthesized compounds 2a act as vermifuge and no compound was found to be a vermicide. The compound 2c was found to be most active against E.coli and P. aeurigenosa and 2e be most active against B.subtilis and S.aureus. The derivative 2h shows good activity against C.albicans and A.niger.