Water → (RS)-7-fluoro-8-{3-[4-(2-hydroxyethoxy)phenyl]-1-piperazinyl}-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

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Reaction Conditions

Reaction Steps

A suspension of 7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (1.015 g) and (RS)-2-[4-(2-hydroxyethoxy)phenyl]-piperazine (1.7 g) in dimethyl sulphoxide (15 cc) is heated with stirring to a temperature in the region of 100° C. for 2 hours and a half. After cooling to approximately 20° C., the suspension is treated with water (30 cc), drained and washed with water (3×10 cc). After one recrystallization in dimethylformamide (15 cc), (RS)-7-fluoro-8-{3-[4-(2-hydroxyethoxy)phenyl]-1-piperazinyl}-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (1.2 g)is obtained in the form of a yellow solid, m.p. 276° C.

Provenance & Evidence