Hydrochloric Acid → 1-Methylamino-6,8-difluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid

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Reaction Steps

A mixture of 1.95 g of 1-methylamino-6,7,8-trifluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid, 3.05 g of anhydrous piperazine and 20 ml of dry pyridine is refluxed for 6 hours. The solvent is stripped off in vacuo, the residue is taken up in 20 ml of water, the pH is brought to 7-8 with half-concentrated hydrochloric acid, with cooling, and the precipitate is filtered off with suction, washed with ice-water and dried at 100° C. in vacuo. 1.8 g of 1-methylamino-6,8-difluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid of decomposition point 276°-278° C. are obtained.

Provenance & Evidence