反应详情

The 8-chloro-3-ethoxycarbonyl-7-fluoro-1-(N-formyl-N-methylamino)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthpyridine is prepared under the conditions of Example 1 but starting from 19.25 g of ethyl 2-(2,7-dichloro-6-fluoroquinoline-3-carbonyl)-3-dimethylaminoacrylate, 4.05 g of N-formyl-N-methylhydrazine and 1.6 g of DBU in 200 cm3 of ethanol. 16.4 g of 8-chloro-3-ethoxycarbonyl-7-fluoro-1-(N-formyl-N-methyl-amino)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine are obtained in the form of a colorless solid melting at 296°-298° C., which is used for the subsequent steps without further purification.