Hydrochloric Acid → 1-(2,4-Difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-1,8-naphthyridine-3-carboxylic acid hydrochloride

Participants

Reaction Steps

In 1.2 ml of 6N hydrochloric acid was suspended 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-1,8-naphthyridine-3-carboxylate, and the resulting suspension was subjected to reaction under reflux for 2 hours. Subsequently, 2 ml of water was added thereto and crystals were collected by filtration and washed with 1 ml of water to obtain 190 mg (yield 93.2%) of 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-1,8-naphthyridine-3-carboxylic acid hydrochloride having a melting point of 249°-252° C. (decomp.).

Provenance & Evidence