1-(2-Hydroxyethyl)piperazine → 1,8-naphthyridine-3-carboxylic Acid

Participants

Reaction Steps

7-Fluoro-8-[4-(2-hydroxyethyl)-1-piperazinyl]-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid is prepared under the conditions of Example 1 but starting from 1.6 g of 8-chloro-7-fluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid and 6.8 g of 1-(2-hydroxyethyl)piperazine in 16 cm3 of pyridine. After concentrating the reaction mixture to dryness under reduced pressure, the residue is taken up in 50 cm3 of water. The mixture is brought to pH 6.9 by adding 0.4 cm3 of acetic acid. The precipitate obtained is drained, washed with twice 10 cm3 of water and recrystallized twice from 10 cm3 of dimethyl-formamide. 1.1 g of 7-fluoro-8-[4-(2-hydroxyethyl)-1-piperazinyl]-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 275°-276° C.

Provenance & Evidence