Synthesis and biological evaluation of novel indolyl-dihydropyridin-3-carboxylate, dihydro[1,2,4]triazol[1,5]pyridin-3-carboxylate and carbohydrazide derivatives

Abstract

The present study anticipates the development of novel antioxidant, antimicrobial and antitubercular drugs by using the indole scaffold. Novel indole derivatives, (4a-c), (5a-c) and (6a-i) have been prepared. The structures of all these unknown compounds have been confirmed with the help of elemental analysis, IR, ¹H & ¹³C NMR and mass spectral data. All these previously unknown synthesized compounds screened for their antioxidant, antimicrobial and antitubercular activities. Compound 5a exhibited good RSA 76.58 %, IC₅₀ value <25 µg/mL. Compound 5a exhibited higher absorbance 0.691nm, at concentration 100 µg/mL. Compound 6a showed good metal chelating activity (64.10 %) at a concentration 100 µg/mL. Compound 6a showed potent activity against S. aureus and P. aeruginosa. Compounds 4a and 5a showed promising antitubercular activity MIC 6.25 µg/mL. Compound 6a showed excellent activity (MIC= 3.125 µg/mL) against                  M. tuberculosis H37Rv, than the standards pyrazinamide (MIC= 3.125) and Streptomycin (6.25 µg/mL).