Ethyl 2-(2-chloro-6,7,8-trifluoro-3-quinolinecarbonyl)(dimethylamino)acrylate 、
2-氟乙胺盐酸盐 、
三乙胺 、
1,8-二氮杂双环[5.4.0]十一碳-7-烯 在
3-ethoxycarbonyl-1-(2-fluoroethyl)-7,8,9-trifluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine 作用下,
以
乙醇 为溶剂,
以After the same treatment of the reaction mixture as in Example 24, 3-ethoxycarbonyl-7,8,9-trifluoro-1-(2-fluoroethyl)-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (2.8 g) is obtained in the form of a yellow solid, m.p. 302°-304° C.的产率得到3-ethoxycarbonyl-1-(2-fluoroethyl)-7,8,9-trifluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine