2,3 - Dimethoxy-5 - Methyl - 6 - (3 - Methyl - 2 - Hydroxy - 3 - En-1 - Butyl) -1,4 - Hydroquinone-o, O- Dibenzyl Ether Synthesis And Process Optimization

6-(2'-Hydroxy-3'-methylbut-3'-enyl)-2,3-dimethoxy-5-methylhydroquinone O,O'-dibenzyl ether is an important medical intermediate of Coenzyme Q10. A commercial and practical synthesis route with Coenzyme Q0 as material by catalytic hydrogenation, alkylation, benzylation, following epoxidation and isomerization is chosen in this paper.The condition of the first reaction is moderate. The hydrogenation of Q0 catalyzed by Pd/C could almost be carried out quantificationally and the product can be used as material of the next reaction without purification. The optimized conditions of the second to reaction are : the ratio of m(Qo) to m(catalyst) to m(2-Hydroxy-2-methlbut-3-ene) equals tol:0.19:1.5, reaction temperature is 45℃, reaction time is 2 ~2.5hours and droping time is 30min. The yield 90.24% and the content is 95.24%. The optimized conditions of the third reaction are : the ratio of m (alkylation material) to m(NaH) is 1:2.4, reaction temperature is 25℃, reaction time is 3 hours and the reducing agent H was added to improve reaction yield and product purity. The yield of this step is 91.91%. Benzylation product could react with peracetic acid quantificationally under 0℃ and the yield is 98.6%. The solvent E was used to replace silica gel chromatography for separation of epoxide during purification. The yield of the crystallization is 91.91% and the cost is greatly reduced. The yield of the isomerization is 92% and the product with high purity can be used in the following reactions.