Hydrochloric Acid → 1-Cyclopropyl-7-fluoro-8-(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

Participants

Reaction Steps

A suspension of 0.47 g of 1-cyclopropyl-7,8-difluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid and 0.6 g of 1-methylpiperazine in 7 cm3 of dimethyl sulphoxide is heated at a temperature close to 80° C. for 15 minutes. The reaction mixture is poured into 25 cm3 of water and 9 cm3 of N hydrochloric acid are added. The solid obtained is drained and washed with 3 times 5 cm3 of water. After recrystallizing once from a mixture of 4.5 cm3 of ethanol and 4.5 cm3 of dimethylformamide, 0.29 g of 1-cyclopropyl-7-fluoro-8-(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid is obtained in the form of a yellow solid melting at 250° C.

Provenance & Evidence