2,3-二甲氧基-5-甲基-1,4-苯醌的合成研究

以对甲酚(2)为原料,经溴化、甲氧基化、甲醚化、氧化四步反应合成了辅酶Q10的重要中间体2,3-二甲氧基-5-甲基-1,4-苯醌(1),(2)与溴反应得到2,6-二溴-4-甲基-苯酚(3),收率95.2%,(3)与甲醇钠在DMF做溶剂和CuBr催化的条件下反应得到2,6-二甲氧基-4-甲基-苯酚(4),收率91.6%,(4)与硫酸二甲酯反应生成3,4,5-三甲氧基甲苯(5),此步反应中采用加入相转移催化剂四丁基溴化铵不仅缩短了反应时间且提高了产率,收率87.3%,(5)与H2O2通过氧化反应,得到目标产物(1),收率61.5%,纯度99%。四步反应的总收率达到46.9%。并通过IR和1H NMR确定了目标化合物及中间体的结构。

Study on the Synthesis of 2,3-Dimethoxyl-5-methyl-1,4-quinone

2,3-Dimethoxyl-5-methyl-1,4-quinone,an important intermediate of coenzyme Q_(10),was obtained via a four-step process using p-cresol(2[STBZ]) as starting material.(2) reacted with bromine to give 2,6-dibromo-4-methyl-phenol(3) with a 95.2% yield.2,6-Dimethoxyl-4methyl-phenol(4) was obtained through the reaction between(3) and sodium methylate with DMF as solvent and CuBr as catalyst.a 91.6% yield was realized.Methylation with dimethylsulfate was employed to give 3,4,5trimethoxytoluence(5).In this step,a phase transfer catalyst was used to shorten the reaction-time and to improve the yield,which was about 87.3%,The target product was obtained through the oxidation reaction between([STHZ]5) and H_2O_2 with a 61.5% yield and 99% purity.The total yield of the process reached 46.9%.The target compound was identified by IR and()~1H NMR.