2,2-Dimethylpiperazine → HCID 20063307, compound

Participants

Reaction Steps

A suspension of 2 g of 8-chloro-7-fluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid in 7.44 g of 2,2-dimethylpiperazine and 20 cm3 of pyridine is heated at a temperature close to 115° C. for 44 hours. The reaction mixture is concentrated to dryness under reduced pressure (20 kPa) at about 60° C. The residue is taken up in 50 cm3 of ethanol and again concentrated, under reduced pressure, under the above conditions. The solid obtained is taken up in 50 cm3 of diethyl ether, drained, washed with twice 30 cm3 of the same solvent and taken up in 120 cm3 of water and 2 g of methanesulphonic acid. A very small amount of insoluble matter is removed by filtering through diatomaceous silica. 2 cm3 of 50% aqueous potassium hydroxide solution are added to the solution obtained. The precipitate formed is drained and washed with 3 times 25 cm3 of water and a single amount of 50 cm3 of ethanol at about 50° C. 1.6 g of 8-(3,3-dimethyl-1-piperazinyl)-7-fluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid are obtained in the form of a yellow solid melting at 362°-365° C., solvated by 4.9% of water.

Provenance & Evidence