反应详情

The mixed solution of acetic anhydride (3 ml) and acetic acid (3 ml) was cooled and nitric acid (3 ml) was added cautiously with stirring. Then a solution of 2,2,4,6,7-pentamethyl-3-phenyl-2,3-dihydrobenzofuran (3.7 g, 13.9 mmol) in acetic anhydride (3 ml) was added dropwise and the mixture was stirred for 30 minutes. The reaction mixture was poured into ice-cold water and the product was extracted with ethyl acetate. The extract was washed with saturated sodium bicarbonate solution, dried and concentrated. The residue was purified by column chromatography on silica gel (hexane-isopropyl ether, 9:1) and crystallized from methanol to obtain the desired compound (2.08 g, yield: 48.1%), m.p. 155°-156° C.

1. stirringthe mixture was stirred for 30 minutes
2. additionThe reaction mixture was poured into ice-cold water
3. extractionthe product was extracted with ethyl acetate
4. washThe extract was washed with saturated sodium bicarbonate solution
5. customdried
6. concentrationconcentrated
7. customThe residue was purified by column chromatography on silica gel (hexane-isopropyl ether, 9:1)
8. customcrystallized from methanol