SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF INDOLE DERIVATIVES BEARING BENZIMIDAZOLE/BENZOTHIAZOLE MOIETY

Abstract

Objective: The present work deals with the synthesis and characterization of biologically active new indole derivatives viz., 2-((1H-benzo[d]imidazol-2-yl)thio)-N-(4-(3-(1H-indol-3-yl)acryloyl)phenyl)acetamide 6a-d, N-(4-(3-(1H-indol-3-yl)acryloyl)phenyl)-2-((5-methoxy-1H-benzo[d]imidazol-2-yl)thio)acetamide 7a-d and N-(4-(3-(1H-indol-3-yl)acryloyl)phenyl)-2-(benzo[d]thiazol-2-ylthio)acetamide 8a-d.Methods: All these newly synthesized compounds were screened for their in vitro antimicrobial activity by an agar plate diffusion method, antioxidant activities: like 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity (RSA), ferric ions (Fe3+) reducing antioxidant power (FRAP), ferrous (Fe2+) metal ion chelating activity.Results: The structures of all the newly synthesized compounds were characterized by their IR, 1HNMR, mass spectral studies and elemental analysis. Compounds 6b, 7a, 7b, 8a and 8b exhibited good radical scavenging activity (RSA) at a concentration 100 µg/ml, compounds 7b, 7c, 7d and 8b displayed good ferric ions (Fe3+) reducing antioxidant power (FRAP) at a concentration 100 µg/ml, compounds 7b, 7d, 8b and 8d showed good ferrous (Fe2+) ion metal chelating activity. Compounds 7d and 8d exhibited good activity against all the screened bacteria and fungi.Conclusion: The synthesised compounds 7d having methoxy group at 5 positions of benzimidazoles ring, bromo group at 5 positions of indole ring, and 8d having bromo group at position 5 of indole ring, both the compounds have exhibited potent antimicrobial activity. Some compounds have shown very good antioxidant activity.