Piperazine → 6-Fluoro-1-(2,4-difluorophenyl)-1,4-dihydro-5-methyl-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid

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Reaction Steps

A solution of 0.76 g (2.00 mmol) of ethyl 6,7-difluoro-1-(2,4-difluorophenyl)-1,4-dihydro-5-methyl-4-oxo-3-quinolinecarboxylate, 0.69 g (8.00 mmol) of anhydrous piperazine, and 30 ml of acetonitrile was refluxed for 18 hours, cooled, and concentrated. The residue was dissolved in 20 ml 6N hydrochloric acid and refluxed for three hours. The suspension was cooled, concentrated by half and filtered, and the solids were washed with water. The crude product was suspended in water which was made basic (pH 12), filtered, and neutralized to pH 6.8. The precipitate was filtered and neutralized to pH 6.8. The precipitate was filtered, washed with water, and dried to give 0.58 g of the title compound, mp 198°-200° C.

Provenance & Evidence