| 摘要 |
<p>PROBLEM TO BE SOLVED: To easily obtain a 2,3,5-trimethylhydroquinone diester useful as a synthetic intermediate for vitamin E, etc., in high yield by reacting a specific dione with an acylation agent in the presence of a specific easily handleable inexpensive catalyst. SOLUTION: The objective trimethylhydroquinone diester of formula II is produced by reacting 2,6,6-trimethyl-cyclohex-2-ene-1,4-dione of formula I (ketoisophorone or KIP) with an acylation agent in the presence of a catalytic amount of a protonic acid. The reaction is carried out by using an acid catalyst comprising one or more kinds of carboxylic acids (n) selected from orthoboric acid and/or boric anhydride or boric acid triester on one hand and from hydroxycarboxylic acid and a (hydroxy-containing) dicarboxylic acid or tricarboxylic acid on the other hand. The amount of the combined catalyst is preferably 0.1-10 mol%; based on the ketoisophorone used in the reaction.</p> |
