1-(4-Fluorophenyl)piperazine → 1-(2,4-Difluorophenyl)-7-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

Participants

Reaction Steps

1-(2,4-Difluorophenyl)-7-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid was prepared under the conditions of Example 1, but from 1.55 g of 7,8-difluoro-1-(2,4-difluorophenyl)-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid and 1.58 g of 4-(4-fluorophenyl)piperazine in 15 cm3 of dimethyl sulphoxide. After recrystallizing once from 55 cm3 of dimethylformamide, 1.4 g of 1-(2,4-difluorophenyl)-7-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid were obtained in the form of a yellow solid melting at about 322° C.

Provenance & Evidence