Water → RP60556A

Participants

Reaction Conditions

Reaction Steps

A suspension of 10.5 g of ethyl 7-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylate in 100 cm3 of acetic acid and 100 cm3 of 17.5% aqueous hydrochloric acid solution was heated, with stirring, at a temperature around 110° C. for approximately 4 hours. After cooling to approximately 20° C., 25 cm3 of water were added to the reaction mixture. The insoluble material was filtered off and washed 3 times with 200 cm3 of water and 2 times with 100 cm3 of ethanol. 9.3 g of 7-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid were obtained in the form of a yellow solid melting at approximately 320° C., which solid was used without additional purification in the subsequent stages.

Provenance & Evidence