Synthesis of 3-(3-Methyl-4-benzenesulfonyl-2-butenyl)-4,5,6-trimethoxy-2-methylphenyl Benzyl Ether by Ultrasonic

3-(3-Methyl-4-benzenesulfonyl-2-butenyl)-4,5,6-trimethoxy-2-methylphenyl benzyl ether,a key intermediate of coenzyme Q10,was synthesized from 3,4,5-trimethoxytoluene(Ⅰ) in overall yield of 57.1%.6-Methyl-2,3,4-tri-methoxybenzaldehyde(Ⅱ) was obtained from Ⅰ via Vilsmeier-Haack reaction in 94.1% yield and converted to 6-methyl-2,3,4-trimethoxyphenol(Ⅲ) via Dakin reaction in 96.2% yield.Phenolic hydroxyl protection of Ⅲ with benzyl bromide produced 6-methyl-2,3,4-trimethoxyphenyl benzyl ether(Ⅳ) in 95.0% yield.Bromination of Ⅳ in the presence of organic base produced 5-bromo-2,3,4-trimethoxy-6-methylphenyl benzyl ether(Ⅴ) in 92.2% yield.Under the condition of ultrasonic,Grignard reagent was prepared from Ⅴ,and then coupled with 4-bromo-2-methyl-1-benzenesulfonyl-2-butene to give the target product in 72.0% yield.Structure of the products were confirmed by FTIR and 1HNMR