Acetic Acid → 1-Cyclopropyl-6,7,8-trifluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid

Participants

Reaction Steps

A mixture of 94 g of ethyl 1-cyclopropyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate (7), 600 ml of glacial acetic acid, 450 ml of water and 70 ml of concentrated sulphuric acid is heated under reflux for 1.5 hours. Thereafter, the hot suspension is poured onto ice, and the precipitate is filtered off under suction, rinsed thoroughly with water and dried in vacuo at 100° C. In this manner, 88.9 g of pure 1-cyclopropyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid II of melting point 228°-230° C. (decomposition) are obtained.

Provenance & Evidence