| 摘要 |
A process for the manufacture of a 2,3,5-trimethylhydroquinone diacylate comprising reacting ketoisophorone with an acylating agent in the presence of a NH- or CH-acidic catalyst, particularly certain bis (perfluorinated hydrocarbyl sulphonyl) imides and metal salts thereof and, respectively, certain tris (perfluoroalkanesulphonyl or pentafluorobenzenesulphonyl) methanes and metal salts thereof. The acylating agent is particularly an acid anhydride, an acyl halide or an enol ester. The so-obtained 2,3,5-trimethylhydroquinone diacylate can be converted into (all-rac)- alpha -tocopherol by transesterification to yield 2,3,5-trimethylhydroquinone and reaction of the latter with isophytol. (all-rac)- alpha -Tocopherol itself is the most active member of the vitamin E group.
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