反应详情

[2-(1-Cyclohexenyl)-4-oxo-4H-[1]-benzopyran-8-yl]acetic acid (2.0 g) was dissolved in ethanol (50 ml) and to the solution was added conc. sulfuric acid (0.5 ml). The mixture was heated under reflux for 5 hours. After dilution with water, the mixture was extracted with ethyl acetate and the extract was washed with water, dried (MgSO4) and concentrated under reduced pressure to obtain the title compound as crystals. The crystals were recrystallized from ethyl acetate to obtain prisms, yield 1.34 g (61.0%), m.p. 126°-127° C.

1. temperatureThe mixture was heated
2. temperatureunder reflux for 5 hours
3. extractionAfter dilution with water, the mixture was extracted with ethyl acetate
4. washthe extract was washed with water
5. dry with materialdried (MgSO4)
6. concentrationconcentrated under reduced pressure