Methanesulfonic Acid → HCID 14853344, compound

Participants

Reaction Steps

A suspension of 0.98 g of 3-ethoxycarbonyl-7-fluoro-1-methoxy-8-(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine in 15 cm3 of ethanol, 9 cm3 of water and 6 cm3 of 2 N aqueous potassium hydroxide solution is stirred at a temperature close to 20° C. for 1 hour. 6 cm3 of 2 N methanesulphonic acid are added to the solution obtained and the mixture is extracted with 3 times 10 cm3 of trichloromethane. The combined organic extracts are washed with 3 times 5 cm3 of water, dried over magnesium sulphate, filtered and concentrated to dryness under reduced pressure (20 kPa) at about 50° C. The dry extract obtained is taken up in 5 cm3 of diisopropyl ether, drained and washed with twice 2 cm3 of the same solvent. After recrystallizing once from 30 cm3 of dimethylformamide containing 30% of ethanol, 0.3 g of 7-fluoro-1-methoxy-8-(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid is obtained in the form of a brown solid melting at 270° C.

Provenance & Evidence