反应详情

Gas ammonia was bubbled for 30 minutes in a solution of ethyl 8-nitro-4-oxo-4H-benzopyran-2-carboxylate (2.109 g, 8.02 mmol) in anhydrous ethanol (50 ml) and anhydrous tetrahydrofuran (50 ml). After that the mixture was evaporated to dryness and the resulting solid residue was suspended in concentrated hydrochloric acid (20 ml) stirring at room temperature for 4 h. Then the mixture was diluted with water, the solid was recovered by filtration, washed repeatedly with water and dried under vacuum on phosphorous pentoxyde, to obtain 1.515 g of the title product (81% yield).

1. customAfter that the mixture was evaporated to dryness
2. additionThen the mixture was diluted with water
3. filtrationthe solid was recovered by filtration
4. washwashed repeatedly with water
5. customdried under vacuum on phosphorous pentoxyde