Synthesis and Antibacterial Activity of the 4-Quinolone-3-carboxylic Acid Derivatives Having a Trifluoromethyl Group as a Novel N-1 Substituent

Novel 1-trifluoromethyl-4-quinolone derivatives (8a,b) were synthesized, and the antibacterial activity of each was evaluated. An oxidative desulfurization−fluorination reaction was employed to introduce a trifluoromethyl group at the N-1 position as a key step. Among the derivatives, 8a was found to exhibit antibacterial activity comparable to that of norfloxacin (1) against Staphylococcus aureus Smith, Streptococcus pneumoniae IID1210, and Escherichia coli NIHJ JC-2.