反应详情

1-hydroxy-2-(tetrahydropyran-2-yl)oxy-3-chloropropane can be prepared by the following scheme: epichlorohydrin is reacted with acetic acid in the presence of a catalytic amount of iron trichloride to give a mixture of 1-acetyloxy-3-chloropropan-2-ol and 2-acetyloxy-3-chloropropan-1-ol, the major component. The mixture is treated with dihydropyran in the presence of p-toluenesulfonic acid for five hours at 25° C. to give a mixture of 1-acetyloxy-2-(tetrahydropyran-2-yl)oxy-3-chloropropane and 1-(tetrahydropyranyloxy)-2-acetyloxy-3-chloropropane. The mixture is added to a rapidly stirred mixture of aqueous methanol and potassium carbonate at 25° C. and stirred for two hours. Evaporation of the methanol, extraction and drying yields a mixture 1-hydroxy-2-(tetrahydropyran-2-yl)oxy-3-chloropropane and 1-(tetrahydropyran-2-yl)oxy-2-hydroxy-3-chloropropane. Fractional vacuum distillation yields pure 1-hydroxy-2-(tetrahydropyran-2-yl)-oxy-3-chloro-propane since the minor impurity is converted into the more volatile epoxy compound during the distillation procedure.

1. customto give
2. customto give
3. customEvaporation of the methanol, extraction
4. customdrying