一锅法简便合成2,6-二甲基苯硼酸

Preparation of 2,6-dimethylphenyl Boronic Acid by One-pot Grignard Reaction

报道了2,6-二甲基苯硼酸的简便合成新方法.对硼化试剂、反应物比例、溶剂等条件进行了优化,优化后的合成条件为:选用硼酸三丁酯为硼化剂、四氢呋喃为溶剂,将加有2,6-二甲基溴苯、硼酸三丁酯物质量比(n(C8H9Br)∶n(B(OC4H9)3)为1∶1.5的四氢呋喃溶液滴加到1.2当量的镁屑中,于30℃一锅反应2 h后,经酸化水解得产品,分离后的总产率为80.1%.并对产品进行了1H NMR、质谱和IR表征.

A simple and convenient ＂one-pot＂ method is described for the preparation of 2,6-dimethylphenyl boronic acid.Parameters affecting preparation reaction including the boronation reagent,reactant proportion and solvent were investigated in detail.An optimized process was obtained when the solution of 2,6-dimethylphenyl bromide,tributyl borate and THF was added to the magnesium chip by drop,the reactant proportion was n（Mg）∶ n（C8H9Br）∶ n（B（OC4H9）3） = 1.2∶ 1∶ 1.5.The reactant solution was kept in a water bath at 30 ℃ for 2 h,then hydrolyzed in acid medium.The isolated yield is 80.1%.The product was characterized by 1H NMR,mass spectrum and IR.