【摘要】 选用硼酸三丁酯为硼化剂,利用格氏试剂法制备了2,6-二甲基苯硼酸,考察了温度、硼化试剂和反应物配比对产率的影响,得出了较佳的合成条件:先由0.1mol2,6-二甲基溴苯与0.12mol镁在43℃反应1.5h制得格氏试剂(产率98.2%),然后与0.2mol硼酸三丁酯在-10℃下发生亲核取代,2h快速升温至20℃,经酸性水解得产品,分离后总产率由有机锂法的51%提高到72.2%,且反应条件更加温和并对产品进行了核磁共振、质谱和IR表征。更多还原

【Abstract】 2,6-Dimethylphenyl boronic acid was prepared from tributyl borate and Grignard reagent. An optimized process was obtained by investigating the influence of temperature, boronization reagent and reactant proportion on the yield. Grignard reagent was prepared from 2,6-dimethylphenyl bromide and 0.12 mol Mg at 43 ℃ in 1.5 h with a yield of 98.2%, then it reacted with 0.2 mol tributyl borate at -10 ℃, and the reaction mixture was hydrolyzed in an acid medium after the temperature was increased to 20 ℃ in 2 h. The total yield is 72.2%, which is much higher than that(51%) of using organic lithium and the experimental conditions are more moderate. The product was characterized by 1H NMR, mass spectrometry and IR.更多还原