5-三氟甲基-2-氯-4-吡啶硼酸的合成研究

Study on synthesis of 2-chloro-5-trifluoromethyl pyridine-4-yl-boronic acid

采用2-氯-4-碘-5-三氟代甲基吡啶为起始原料,与正丁基锂溶液反应制备5-三氟甲基-2-氯-4-吡啶硼酸。实验研究了合成反应过程几种反应条件对合成产率的影响情况,采用HPLC,FTIR,1 H NMR等方法对产品的纯度和结构进行了分析表征。实验结果表明:当反应温度为-70℃,反应时间为2h,反应物料配比n(2-氯-4-碘-5-三氟代甲基吡啶)∶n(硼酸三丁酯)∶n(正丁基锂)为1.00∶1.20∶1.20,溶液pH值为9.0时,5-三氟甲基-2-氯-4-吡啶硼酸的收率为83.10%,纯度可达98.65%以上。

2-chloro-5-trifluoromethyl pyridine-4-yl-boronic acid was prepared with 2-chloro-4-iodo-5-trifluoromethyl pyridine as the raw material through reaction with n-butyl lithium reagent.Several reaction conditions of the synthesis process were studied through the experiment.The purity and structure of the products were characterized by HPLC,FTIR and 1H NMR.Experimental result shows that when the temperature is-70 ％C,the reaction time is 2 h,the molar ratio of n（C6 H2C1F3 IN） ∶ n（Q2H27BO3） ∶ n（C4H9Li） is 1.00 ∶ 1.20 ∶ 1.20,and the pH is 9.0,the yield of 2 chloro 5 trifluoromethyl pyridine-4-yl-boronic acid reaches 83.10％,and its purity is up to 98.65％.