Design, Synthesis and Biological Screening of 2, 4- Disubstituted Quinolines

A series of 2,4 disubstituted quinoline derivatives were synthesized though multi-step reactions. Aniline was reacted with benzaldehyde and pyruvic acid to form 2-Phenylquinolin-4-carboxylic acid 1 and converted to 2-Phenylquinolin- 4-carbonyl chloride 2, which on subsequent reaction with substituted amines gave 2-Phenylquinoline-4-substituted Phenylcarboxamide 3. The newly synthesized title compounds were evaluated for their antibacterial and antifungal activities against B. subtilis, K. pneumonia, E. coli, S. aureus, A. niger as well as anticancer activity. Preliminary results indicated that most of the 2,4 Diphenyl quinoline derivatives demonstrated good antibacterial and antifungalactivities. Among the newly synthesized compounds, N-2-Diphenyl quinolin-4- carboxamide 3a and N-p-Tolylquinolin-4-carboxamide 3f were found to possess maximum anticancer activity. It was concluded that two bulky aryl groups at 2 and 4 positions enhances the activity of synthesized quinoline derivatives. The compounds N-p-Tolylquinolin-4-carboxamide 3f and 2-Phenyl-N-(pyridin-2-yl) quinolin-4-carboxamide 3j were found to possess maximum activity against the tested strains of B. subtilis, K. pneumonia, E. coli, S. aureus and A. niger. It can be concluded that two bulky aryl groups at 2 and 4 positions enhances the activity of quinoline derivatives.