2-氯-3-氟溴苯的合成

Synthesis of 2-Chloro-3-fluorobromobenzene

以3-氯-2-氟苯胺为原料,经溴化和重氮化反应得到2-氯-3-氟溴苯,总摩尔产率约82.5%,纯度≥99%(GC)。产物的结构通过MS及1H NMR验证。其中,溴化反应一步合理的反应条件为:n(3-氯-2-氟苯胺)∶n(NBS)=1∶1.005,溴代时反应温度为10±2℃;重氮化反应条件为:n(4-溴-3-氯-2-氟苯胺)∶n(亚硝酸钠)=1∶1.25,反应温度为80℃左右。该法具有反应条件温和、易于工业化生产的优点。

2-Chloro-3-fluorobromobenzene was synthesized from 3-chloro-2-fluoroaniline by bromization and diazotization with an overall yield of 82.5% and purity of 99.538%（GC）.The structure of the product was confirmed by MS and 1H NMR.The optimized conditions of bromization were： n（3-chloro-2-fluoroaniline）∶n（NBS）= 1∶1.005,temperature at 10±2 ℃;The optimized conditions of diazotization were： n（4-bromo-3-chloro-2-fluoroaniline）∶n（NaNO2） = 1∶1.25,temperature at 80 ℃.The reaction conditions of this procees is mild,and it is suitable for production in industrial scale.