Mannich bases of 7-piperazinylquinolones and kojic acid derivatives: synthesis, in vitro antibacterial activity and in silico study.

Novel Mannich bases of 7-piperazinylquinolones with kojic acid and chlorokojic acid were designed as new quinolone antibacterials. All compounds showed significant in vitro antibacterial activity against both Gram-positive and Gram-negative bacteria. Particularly, chlorokojic derivative 2b was the most potent compound against Staphylococcus aureus and Pseudomonas aeruginosa (MIC values≤0.19 μg/mL). Its activity was 4-8 times more than that of standard drug norfloxacin. The molecular docking study of compound 2b further supported the molecular basis of the designed compounds.