Acetic Acid → (RS)-7-Fluoro-1-methoxy-4-oxo-8-(3-phenyl-1-piperazinyl)-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A suspension of 7,8-difluoro-1-methoxy-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (2 g) and (RS)-2-phenylpiperazine (2.1 g) in dimethyl sulphoxide (30 cc) is heated with stirring for 15 minutes to approximately 50° C. After cooling to approximately 20° C., the reaction mixture is poured into water (100 cc) and treated with acetic acid (1.2 cc). The insoluble matter is drained, washed with water (3×10 cc) and recrystallized in dimethylformamide (80 cc). (RS)-7-Fluoro-1-methoxy-4-oxo-8-(3-phenyl-1-piperazinyl)-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (2 g) is obtained in the form of a yellow solid, decomposing at 284° C.

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