Synthesis, antimicrobial, and anticancer evaluation of novel 2-(3-methylindolyl)benzimidazole derivatives

A series of new N -alkyl-2-(3-methyl-indolyl)benzimidazoles 8 ( a – c ) were synthesized by the condensation of N -alkyl-2-propylbenzimidazole-phenylhydrazone derivatives 7 ( a–c ), in polyphosphoric acid (PPA) underwent cyclization via Fischer-indole synthesis. Alkylation of 8 ( b–c ) with different alkylating agents gave the title compounds 9 ( a–f ). All the synthesized compounds were characterized by spectral data. The newly synthesized compounds 8 ( a–c ) and 9 ( a–f ) which possess a variety of N -substituents in both benzimidazole and indole moieties, were evaluated for their antimicrobial and anticancer activities. The results showed that compounds 9b , 9c, and 9d were active only against Gram-positive bacteria, and selective antibacterial activity was exhibited by compounds 8c and 8e against Staphylococcus aureus MLS-16 and Bacillus subtilis , respectively. Further, compounds 8a , 8b, 8c, 9a , 9e , and 9f showed significant anti-proliferative activity.