(RS)-7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid 、
Piperazine,2-[4-(methoxymethyl)phenyl]- 以(RS)-7-fluoro-8-{3-[4-(methoxymethyl)phenyl]-1-piperazinyl}-1-methyl-4-oxo -1,4-dihydrobenzo[b][1,8]-naphthyridine-3-carboxylic acid (1.70 g) is obtained in the form of a yellow solid的产率得到(RS)-7-fluoro-8-{3-[4-(methoxymethyl)phenyl]-1-piperazinyl}-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]-naphthyridine-3-carboxylic acid