反应详情

Ethyl 1-ethyl-7-methoxy-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate (82 g) was added to a mixture of fuming nitric acid (200 ml) and concd. sulfuric acid (330 ml), then the mixture was heated at 80° C. for 2 hours with stirring. The mixture was poured into 500 ml of ice-water. The precipitate was collected, washed with water, and dried. Recrystallization from ethanol gave 93.5 g of ethyl 1-ethyl-1,4-dihydro-7-methoxy-6-nitro-4-oxo-1,8-naphthyridine-3-carboxylate, m.p. 223.5°-227° C.

1. customThe precipitate was collected
2. washwashed with water
3. customdried
4. customRecrystallization from ethanol