2-(4-Methoxyphenyl)piperazine → (RS)-3-ethoxycarbonyl-7,9-difluoro-8-[3-(4-methoxyphenyl)-1-piperazinyl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A suspension of 3-ethoxycarbonyl-7,8,9-trifluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (2.5 g) and (RS)-2-(4-methoxyphenyl)piperazine (3.5 g) in dimethyl sulphoxide (40 cc) is heated with stirring to a temperature in the region of 95° C. for 2 hours. After treatment of the reaction mixture according to the conditions described in Example 39, (RS)-3-ethoxycarbonyl-7,9-difluoro-8-[3-(4-methoxyphenyl)-1-piperazinyl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (2.8 g) is obtained in the form of a yellow solid, m.p. 209° C., which is used without further purification for the subsequent steps.

Provenance & Evidence