2-Methylpiperazine → HCID 14700559, compound

Participants

Reaction Steps

A suspension of 3.5 g of 8-chloro-7-fluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid and 4.6 g of 2-methylpiperazine in 40 cm3 of pyridine is heated at a temperature close to 115° C., with stirring, for 13 hours. The reaction mixture is concentrated to dryness under reduced pressure (20 kPa) at 60° C. The residue is twice taken up with 30 cm3 of ethanol and concentrated under reduced pressure under the above conditions. The solid obtained is taken up in 60 cm3 of water and 10 cm3 of 30% aqueous potassium hydroxide solution. The aqueous phase is washed with twice 100 cm3 of trichloromethane, 10.28 g of methanesulphonic acid are added and the aqueous phase is again washed with twice 100 cm3 of trichloromethane. 10 cm3 of 30% aqueous potassium hydroxide solution are added. The precipitate formed is drained and washed with 3 times 10 cm3 of water and twice 10 cm3 of ethanol. 2.7 g of 7-fluoro-1-methyl-8-(3-methyl-1-piperazinyl)-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid are obtained in the form of a yellow solid melting at 360°-363° C.

Provenance & Evidence