Acetic Acid → 5,6,7,8-Tetrafluoro-1-(2,4-difluorophenyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid

Participants

Reaction Steps

40.1 g of ethyl 5,6,7,8-tetrafluoro-1-(2,4-difluorophenyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylate are added to a mixture of 28.5 ml of concentrated sulphuric acid, 250 ml of glacial acetic acid and 200 ml of water and the mixture is heated under reflux for 2 hours. The hot solution is poured onto ice and the precipitate is filtered off with suction, washed with water and dried. 34.5 g of the title compound of melting point 250°-252° C. are obtained.

Provenance & Evidence