反应详情

温度

50 °C

A mixture of 5-hydroxy-2,2-dimethyl-4H-1,3-benzodioxin-4-one (123 g, 633 mmol, Synth. Commun. 1994, 24, 1025), potassium carbonate (262 g, 1.9 mol) and 2,2,2-trifluoroethyl trifluoromethanesulfonate (95.8 mL, 665 mmol) in N,N-dimethylformamide (600 mL) was stirred at 50° C. for 30 min. Then methanol (300 mL) was added to the mixture, and stirring was continued for 5 h at that temperature. After cooling to room temperature, the mixture was diluted with water (500 mL) and neutralized with 2N hydrochloric acid. Product was extracted with a mixture of ethyl acetate-hexane (5:1, 500 mL×3). Combined organic layers were washed with water (500 mL), dried over magnesium sulfate and concentrated under reduced pressure. The residual solid was recrystallized from methanol-water to afford 125 g (79%) of the desired product as colorless crystals.

1. stirringstirring
2. waitwas continued for 5 h at that temperature
3. temperatureAfter cooling to room temperature
4. extractionProduct was extracted with a mixture of ethyl acetate-hexane (5:1, 500 mL×3)
5. washCombined organic layers were washed with water (500 mL)
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residual solid was recrystallized from methanol-water