反应详情

Ethyl 6-ethoxy-4-hydroxy-1,5-naphthyridine-3-carboxylate (3.0 g) was added to phosphorus oxychloride (25 ml), with stirring, at ambient temperature. The mixture was heated at 50° C. for 45 minutes. The mixture was cooled to 10° C. and added to ice/water at less than 5° C. The mixture was then basified with concentrated aqueous ammonia solution SG 0.88 at less than 5° C. The mixture was extracted with dichloromethane to give ethyl 4-chloro-6-ethoxy-1,5-naphthyridine-3-carboxylate, m.p. 61°-64° C.

1. temperatureThe mixture was heated at 50° C. for 45 minutes
2. temperatureThe mixture was cooled to 10° C.
3. extractionThe mixture was extracted with dichloromethane