反应详情

3-Benzoyloxy-2-methyl-4-pyrone (40.60 g, 176.5 mmol) is stirred at 20°-25° C. for 3 hours with 265 ml (530 mmol) of 2N sodium hydroxide solution. The solution is adjusted to pH 6.5 and extracted three times with 200 ml of dichloromethane each time. The combined organic phases are dried over sodium sulphate and concentrated on a rotary evaporator. The crude product is recrystallized in acetone and gives 8.90 g (40%) of 3-hydroxy-2-methyl-4-pyrone, m.p. 156°-158° C.

1. extractionextracted three times with 200 ml of dichloromethane each time
2. dry with materialThe combined organic phases are dried over sodium sulphate
3. concentrationconcentrated on a rotary evaporator
4. customThe crude product is recrystallized in acetone