To a mixture consisting of 23.3 g (0.153 mol) of 2,3,5-trimethylhydroquinone, 17.5 g (0.128 mol) of zinc chloride, 54 ml of ethyl acetate and 2.5 g of concentrated hydrochloric acid, 46.1 g (0.153 mol) of isophytol (purity: 98.3%) was added dropwise under stirring at 25-30° over 3 hours. At the same temperature, the reaction mixture was stirred for an additional 2 hours. After the reaction mixture was washed with 10 ml of water, the solvent was distilled off. Toluene (100 ml) was added to the residue to dissolve the same. The resulting solution was washed successively with water, alkaline water and a saturated aqueous solution of NaCl, dried over magnesium sulfate and then concentrated under reduced pressure, whereby 66.0 g of the title compound was obtained as a brown oil (yield: 95.2%, GLC purity: 95.1%, α-tocopheryl acetate content: 2.0%, ethyl acetate recovery rate: 50%).
