反应详情

A solution of ethyl 6-acetoxy-2,5,7,8-tetramethylchroman-2-acetate (36.5 g, ~108 mmol) and 50% aqueous sodium hydroxide (110 mL) in a mixture of ethanol (500 mL) and water (500 mL) was stirred at ambient temperature for 7 h. The reaction mixture was extracted with hexane (2×200 mL). The pH of the resulting solution was adjusted to ~2 with concentrated hydrochloric acid. Water (~200 mL) was added and the reaction mixture was cooled in an ice/water bath. Crystallization was induced by scratching with a glass rod and the solid that formed was collected by filtration. The solid was recrystallized from an ethanol/water mixture to give 20.2 g (70.9% yield) of the desired product as a tan solid.

1. extractionThe reaction mixture was extracted with hexane (2×200 mL)
2. additionWater (~200 mL) was added
3. temperaturethe reaction mixture was cooled in an ice/water bath
4. customCrystallization
5. customthe solid that formed
6. filtrationwas collected by filtration
7. customThe solid was recrystallized from an ethanol/water mixture