Collect. Czech. Chem. Commun. 1989, 54, 2181-2189

Synthesis of some 1-aryl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids and their antibacterial activity

Stanislav Rádl and Viktor Zikán

Research Institute for Pharmacy and Biochemistry, 130 60 Prague 3


1,4-Dihydro-4-oxoquinoline-3-carboxylic acids VIIIc and VIIId were prepared via their ethyl esters VIIIa and VIIIb, which were obtained by a direct arylation of ethyl 7-chloro-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate (VIa). When treated with piperazine or N-methylpiperazine compound VIIId yields VIIIe or VIIIf, respectively. Reduction of VIIId, VIIIe, and VIIIf with ferrous sulfate yields VIIIg, VIIIh, and VIIIi, respectively. Diazotization and introduction of fluorine into VIIIg using hydrogen fluoride-pyridine yields VIIIj. The compounds prepared were tested for their antimicrobial activity in vitro.