Synthesis of Chalcone Derivatives of Furo [3, 2-c] Pyridine as Potential Antibacterial Agents

Encouraged by the biological activities associated with chalcones and furo[3,2-c]pyridine, the present paper describes the synthesis, spectroscopic identification and antibacterial activity of furo[3,2-c]pyridine chalcone derivatives i.e. 8a-8g in a few high yielding steps from commercially available 2-Furaldehyde. Claisen Schmidt condensation of aldehyde 7 with various acetophenones (R = a-g) was accomplished in presence of sodium hydroxide in methanol at room temperature for 2 hours resulted in the formation of chalcones i.e. N-(2-formylfuro[3,2-c]pyridin-4-yl)benzamide (8a-8g). Furo[3,2-c] chalcone derivatives i.e. 8a-8g were screened in-vitro at a concentration of 250 μg/mL for antibacterial activity against two Grampositive pathogenic organisms: Staphylococcus aureus and Staphylococcus pyogenes and two Gram-negative organisms: Escherichia coli and Pseudomonas aeruginosa. It was observed that among all the compounds tested, compound 2methoxy, 4-methoxy and 3,4,5-trimethoxy showed high activity or equipotent against all the tested bacterial strains with reference to the standard drug Ciprofloxacin. Among the other compounds N-(2-((E)-3-oxo-3-phenylprop-1-enyl)furo[3,2c]pyridin-4-yl)benzamide and N-(2-((E)-3-(3-bromo-4-fluorophenyl)-3-oxoprop-1-enyl)furo[3,2-c]pyridin-4-yl)benzamide (8a and 8g) showed moderate activity, while compounds N-(2-((E)-3-(3-bromophenyl)-3-oxoprop-1-enyl)furo[3,2-c] pyridin-4-yl)benzamide and N-(2-((E)-3-(4-bromophenyl)-3-oxoprop-1-enyl)furo[3,2-c]pyridin-4-yl) benzamide (8e and 8f) showed least activity against all the tested pathogenic organisms.