反应详情

Fuming nitric acid (200 ml) was cooled to from -30° to -35° C. and 4-chromanone (29.0 g) was added with stirring over 30 minutes. The mixture was further stirred for 30 minutes at the intact temperature and successively poured into ice water. The resulting mixture was extracted with ethyl acetate (2,500 ml). The organic layer was dried with anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure to obtain the crude product as a yellow solid. The crude product was washed with a solvent mixture, n-hexane:ethyl acetate=1:1, to obtain 6-nitro-4-chromanone (27.0 g).

1. additionwas added
2. stirringThe mixture was further stirred for 30 minutes at the intact temperature
3. extractionThe resulting mixture was extracted with ethyl acetate (2,500 ml)
4. dry with materialThe organic layer was dried with anhydrous magnesium sulfate
5. distillationthe solvent was distilled off under reduced pressure
6. customto obtain the crude product as a yellow solid
7. washThe crude product was washed with a solvent mixture, n-hexane