From o-phenylenediamine and p-amino benzoic acid a variety of novel heterocyclic substituted benzimidazole analogs C-N were designed and synthesized by a multistep synthesis. FT-IR, 1H-NMR, Mass spectroscopy and bases of elemental analysis were performed to characterize the structure of synthesized compounds. Test compounds were screened for antitubercular activity against H37RV strains of M. tuberculosis by in vitro M. tuberculosis method. In addition, antimicrobial activity of title compounds was also evaluated against various pathogenic strains of bacteria and fungi by agar streak dilution test. Results of biological studies revealed that all title compounds exhibited mild to good antitubercular and antimicrobial activity. The relationship between the functional group variation and the biological activity of the screened compounds were discussed. The most active compound was found to be 4-(2-(4-(1H-benzmidazol-2-yl)phenyl)hydrazono)-1-(4-chlorophenyl)-3-hydroxy-1H-pyrazol-5(4H)-one H 4-(2-(4-(1H-benzmidazol-2-yl)phenyl)hydrazono)-1-(3-chlorophenyl)-3-hydroxy-1H-pyrazol-5(4H)-one K out of twelve title compounds.
