1-Methylpiperazine → Hydrochloric Acid

Participants

Reaction Steps

A suspension of 2.64 g of 7-chloro-1-cyclopropyl-4-oxo-1,4-dihydro-1,6-naphthyridine-3-carboxylic acid and 2.5 g of N-methylpiperazine in 30 ml of ethanol or DMSO (=Dimethylsulfoxide) was heated to the boiling point under reflux for 16 hours or to 135°-140° C. for two hours. The diluent was distilled off in vacuo, the residue was dissolved in 30 ml of 1N NaOH, the solution was filtered and the filtrate was acidified with 10 strength hydrochloric acid. The precipitate was filtered off and washed with water and ethanol. It could be recrystallised from N-dimethylformamide/ethanol. 3.1 g (94% of the theoretical yield) of 7-(4-methylpiperazino)-1-cyclopropyl-4-oxo-1,4-dihydro-1,6-naphthyridine-3-carboxylic acid of melting point 326° C. (hydrochloride) (decomposition) were obtained.

Provenance & Evidence