3-ethoxycarbonyl-7,8-difluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine   、                                                                                      
2-(2-噻吩基)]哌嗪                                                                                                                                                              在
                                                                                                                                                                                 
(RS)-3-ethoxycarbonyl-7-fluoro-1-methyl-4-oxo-8-[3-(thien-2-yl)-1-piperazinyl]-1,4-dihydrobenzo[b][1,8]naphthyridine                                                                                                                                  作用下,
                                                                                                                                                                                                                            以(RS)-3-Ethoxycarbonyl-7-fluoro-1-methyl-4-oxo-8-[3-(2-thienyl)-1-piperazinyl ]-1,4-dihydrobenzo[b][1,8]naphthyridine (2.25 g) is obtained in the form of a yellow solid, m.p. 228° C.的产率得到(RS)-3-ethoxycarbonyl-7-fluoro-1-methyl-4-oxo-8-[3-(thien-2-yl)-1-piperazinyl]-1,4-dihydrobenzo[b][1,8]naphthyridine