1-Methylpiperazine → 1-Cyclopropyl-6-fluoro-8-methoxy-7-(4-methyl-1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

0.12 g (0.0012 mole) of N-methylpiperazine was added to a solution of 0.09 g (0.0003 mole) of 1-cyclopropyl-6,7-difluoro-8-methoxy-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (IIc) (prepared as described in Preparation 6) in 0.5 ml of dimethyl sulfoxide, and the mixture was stirred at 70° C. for 6 hours. At the end of this time, the solvent and the excess N-methylpiperazine were removed by evaporation under reduced pressure at the same temperature, and the residue was washed with ethyl acetate and subjected to silica gel column chromatography, eluted with methanol, to afford 0.03 g of 1-cyclopropyl-6-fluoro-8-methoxy-7-(4-methyl-1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid as colorless powdery crystals, melting at 211°-214° C.

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