1-(2-Hydroxyethyl)piperazine → 1-Cyclopropyl-7-fluoro-8-[4-(2-hydroxyethyl)-1-piperazinyl]-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

Participants

Reaction Steps

1-Cyclopropyl-7-fluoro-8-[4-(2-hydroxyethyl)-1-piperazinyl]-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid is prepared under conditions analogous to Reference Example 5 but starting from 4 g of 8-chloro-1-cyclopropyl-7-fluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid and 6.2 g of 1-(2-hydroxyethyl)-piperazine in 40 cm3 of pyridine. The reaction mixture is heated for 22 hours at a temperature close to 115° C. The pure product is isolated after recrystallizing 3 times from 3 times 200 cm3 of ethanol containing 10% of dimethylformamide each time. 0.94 g of 1-cyclopropyl-7-fluoro-8-[4-(2-hydroxyethyl)-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 255° C.

Provenance & Evidence