反应详情

In a similar manner to Example B1, ethyl 7-ethoxy-4-hydroxy-1,8-naphthyridine-3-carboxylate (8.8 g) and phosphorus oxychloride (50 ml) were heated at 80° C. for 25 minutes to give ethyl 4-chloro-7-ethoxy-1,8-naphthyridine-3-carboxylate, m.p. 72°-75° C.