Synthesis, antibacterial and antitubercular activities of benzimidazole bearing substituted 2-pyridone motifs.

A series of benzimidazole bearing 2-pyridones 5a-r were synthesized and evaluated for their in vitro antibacterial and antitubercular activity. Further, all compounds were examined for their cytotoxic study on VERO cell line and characterized by well-known spectral techniques. It was observed that the compounds 5h, 5i, 5k, 5q and 5r were found to possess significant broad spectrum antibacterial activity (12.5-100 μg/mL of MIC), while compounds 5g-5i, 5k and 5l proved to be the most potent antitubercular activity in range of 2.76-20.4 μM of MIC at low level of cytotoxicity, indicating good selectivity. From SAR studies, lipophilic profile of compounds was remarkably vital for antibacterial activity, while MIC values of antitubercular activity could not be directly correlated with lipophilicity.