反应详情

4-Benzyloxy-2-hydroxy-acetophenone (20 g, 0.0825 mol), prepared in accordance with Example 4, was dissolved in 150 mL of toluene. To this solution was added diethyl carbonate (25.3 g, 0.21 mol) and the entire contents taken in a beaker was heated while stirring to dissolve the starting material. This solution was then taken in an addition funnel and was added at a rate of 7-8 mL/min (addition time=1.5 hrs) to a suspension of sodium hydride (4.3 g, 10.1 mol) in toluene (100 mL) taken in a 500 mL 4-neck flask equipped with a mechanical stirrer, a distillation apparatus (double jacketed-splitter heads) with a condenser, a thermocouple, and a thermometer to read the temperature of the distillate under N2 atmosphere. The reaction flask was heated to 110°-115° C. with a heating mantle during the addition. Ethanol produced during this reaction is removed as an azeotrope with toluene. Additional toluene was added through the addition funnel to have enough of toluene in the reaction flask. The reaction mixture was refluxed for ~5 hrs to complete the reaction. The contents of the reaction flask were transferred to a separatory funnel and 400 mL of distilled water was added to separate into two phases. The aqueous layer was acidified to pH 2.0 with 1:1 dil. HCl and filtered under vacuum. The crude product was recrystallized from hot methanol; yield 84%.

1. temperaturewas heated
2. dissolutionto dissolve the starting material
3. customThis solution was then taken in an addition funnel
4. customequipped with a mechanical stirrer
5. customa distillation apparatus (double jacketed-splitter heads) with a condenser, a thermocouple, and a thermometer to read
6. temperatureThe reaction flask was heated to 110°-115° C. with a heating mantle during the addition
7. customis removed as an azeotrope with toluene
8. additionAdditional toluene was added through the addition funnel
9. temperatureThe reaction mixture was refluxed for ~5 hrs
10. customthe reaction
11. customThe contents of the reaction flask were transferred to a separatory funnel
12. customto separate into two phases
13. filtrationfiltered under vacuum
14. customThe crude product was recrystallized from hot methanol