Acetic Acid → HCID 20063289, compound

Participants

Reaction Steps

A suspension of 0.8 g of 3-ethoxycarbonyl-7,9-difluoro-1-methyl-4-oxo-8-(1-piperazinyl)-1,4-dihydrobenzo[b][1,8]naphthyridine in 20 cm3 of ethanol and 20 cm3 of N aqueous potassium hydroxide solution is heated at a temperature close to 75° C. for 1 hour and a half. 12 g of a 10% aqueous acetic acid solution are added to the solution obtained, at this temperature. The insoluble matter obtained is drained at about 75° C. and washed 3 times with 30 cm3 of water at about 20° C. After recrystallizing once from 90 cm3 of dimethylformamide, 0.5 g of 7,9-difluoro-1-methyl-4-oxo-8-(1-piperazinyl)-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid is obtained in the form of a yellow solid melting at 345°-347° C.

Provenance & Evidence