Water → RP60556A

Participants

Reaction Conditions

Reaction Steps

A suspension of 5.0 g of 7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid and 6.2 g of 4-(4-fluorophenyl)-piperazine in 30 cm3 of dimethyl sulphoxide was heated, with stirring, at a temperature around 90° 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 with 2 times 25 cm3 of water. After recrystallizing once from 150 cm3 of dimethylformamide, 7.6 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 about 318-9° C.

Provenance & Evidence