反应详情

温度

60 °C

Under a nitrogen atmosphere, a suspension of 10.9 g (32.4 mmol) of methyl 4-[(E)-2-(4,4-dimethyl-6-chromanyl)-2-methylvinyl]benzoate in 100 ml of ethanol was treated by dropwise addition of 100 ml of 6N potassium hydroxide, with stirring at 60° C. After 1 hour a clear solution resulted. The ethanol was removed by evaporation under reduced pressure, and 100 ml of water was added. The resulting mixture was acidified with 125 ml of concentrated hydrochloric acid, and the acidified mixture was extracted with dichloromethane. The combined extracts were dried (MgSO4) and evaporated in vacuo to give 10.4 g (99% yield) of a solid. Recrystallization of 8.4 g of this solid yielded 5.6 g of the title compound, mp 179°-181° C.

1. customAfter 1 hour a clear solution resulted
2. customThe ethanol was removed by evaporation under reduced pressure, and 100 ml of water
3. additionwas added
4. extractionthe acidified mixture was extracted with dichloromethane
5. dry with materialThe combined extracts were dried (MgSO4)
6. customevaporated in vacuo