Water → methyl 2-hydroxy-6,7-dihydro-5H-benzocycloheptene-8-carboxylate

참여 물질

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반응 단계

To methyl 2-methoxy-6,7-dihydro-5H-benzocycloheptene-8-carboxylate (5.07 g, 21.8 mmol) dissolved in dichloromethane (100 ml) was added dropwise at −60° C. to −70° C. (inner temperature) boron tribromide (a 1 M solution in dichloromethane, 87 ml), and the resulting mixture was stirred for 5 hours while raising the temperature from −70° C. to room temperature. The reaction mixture was mixed with diethyl ether and water (100 ml) in the order, and was extracted with dichloromethane (100 ml, 50 ml×2). The combined organic layers were dried with anhydrous magnesium sulfate, and were then concentrated under reduced pressure. To the residue dissolved in methanol (150 ml) was added sulfuric acid (0.5 ml), and the resulting mixture was stirred under reflux with heating (100° C.) for 24 hours. The reaction mixture was concentrated under reduced pressure, was mixed with ethyl acetate (150 ml) and was washed with an aqueous saturated solution of sodium chloride (30 ml×3). After drying with anhydrous magnesium sulfate, the organic layer was concentrated under reduced pressure, diisopropyl ether was added to the residue and an insoluble material was collected by filtration. The insoluble material was washed with diisopropyl ether and was then dried under reduced pressure to obtain methyl 2-hydroxy-6,7-dihydro-5H-benzocycloheptene-8-carboxylate (4.31 g, 19.7 mmol, 90%).

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