Acetic Acid → 1-Cyclopropyl-6,8-difluoro-7-methyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid

Participants

Reaction Steps

A mixture of 30 g of ethyl 1-cyclopropyl-6,8-difluoro-7-methyl-1,4-dihydro-4-oxo-3-quinolinecarboxylate, 210 ml of glacial acetic acid, 160 ml of water and 23.5 ml of concentrated sulphuric acid is heated under reflux for 2 hours. The hot suspension is then poured onto ice and the precipitate is filtered off with suction, rinsed thoroughly with water and dried in vacuo at 100° C. 25.9 g of pure 1-cyclopropyl-6,8-difluoro-7-methyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid of melting point 227°-229° C. are obtained in this manner.

Provenance & Evidence