Ethanol → 7-(Benzyloxy)-4-hydroxy-2H-1-benzopyran-2-one

반응식

[C:1](=[O:8])([O:5][CH2:6][CH3:7])OCC.[H-].[Na+].[CH2:11]([OH:13])[CH3:12].[OH2:14].[C:15]1([CH3:21])[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1>>[CH2:21]([O:13][C:11]1[CH:7]=[C:6]2[C:15]([C:16]([OH:14])=[CH:17][C:1](=[O:8])[O:5]2)=[CH:20][CH:12]=1)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1

참가 물질

반응물 5

HCID 702Ethanol

HCID 962Water

HCID 1140Toluene2회

HCID 7766Diethyl Carbonate

HCID 24758Sodium hydride

생성물 1

HCID 547084427-(Benzyloxy)-4-hydroxy-2H-1-benzopyran-2-one수율 84%

실험 절차

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%.