Potassium Hydroxide → 9-Fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-4-methyl-1-oxo-1,4-dihydrobenzo[f][1,7]naphthyridine-2-carboxylic acid

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Reaction Conditions

Reaction Steps

A suspension of 0.70 g of ethyl 9-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-4-methyl-1-oxo-1,4-dihydrobenzo[f][1,7]naphthyridine-2-carboxylate in a mixture of 250 cm3 of ethanol at 40% and 4 cm3 of a 1 N aqueous potassium hydroxide solution was heated, with stirring, for 8 hours at a temperature of 80° C. After cooling to a temperature of 60° C., the light insoluble material was removed by filtration. The solution was neutralized with 4.1 cm3 of a 1 N aqueous hydrochloric acid solution; the insoluble material formed was dewatered, washed 3 times with 20 cm3 of water and twice with 20 cm3 of ethanol and dried under vacuum at 100° C. 0.56 g of 9-fluoro-8-[4-(4-fluorophenyl)piperazin-1-yl]-4-methyl-1-oxo-1,4-dihydrobenzo[f][1,7]naphthyridine-2-carboxylic acid was obtained in the form of yellow crystals, which melted at 346° C.

Provenance & Evidence