二苯乙炔类液晶化合物的“二步法”合成研究

Synthesis of diphenylacetylene liquid crystal compounds by two-step method

二苯乙炔类化合物是高折射率向列相液晶材料的重要成份,其主要合成方法 Sonogashira偶联反应存在着合成路线较长、产率偏低等缺点,不利于工业化生产。基于Sonogashira偶联反应机理,简化二苯乙炔类液晶化合物的合成步骤,以期缩短合成路线,提高全合成产率。实验结果表明,当以取代溴苯为原料,将二苯乙炔类化合物的合成步骤简化成"二步"时,其全合成产率高达73.72%,比"一步法"提高40%左右,比"三步法"和"多步法"提高15%左右;缩短了合成路线,提高了合成效率;探索出最佳反应条件:以高沸点非质子氢试剂(如甲苯)为溶剂,KOH为碱性物质,DMAP为胺类物质,110℃下反应12 h。

Diphenylacetylene compounds are important components of the nematic liquid crystal materials with high refractive index.At present Sonogashira coupling reaction is the main synthetic method for diphenylacetylene,which is not suitable for industrial production due to long synthetic routine and low yield. Based on the mechanism of Sonogashira coupling reaction mechanism,synthetic steps of diphenylacetylene liquid crystal compounds are simplified in order to shorten synthetic routine and increase yield. Using substituted bromobenzene as raw materials,synthesis of diphenylacetylene compounds is simplified to the two-step method,the total synthetic yield is as high as 73. 72%,which is about 40% higher than that by the single step method,about 15% higher than that by three-step method.The optimum reaction conditions are determined as follows： using high boiling aprotic hydrogen reagent（ toluene） as solvent,KOH as basic substance,DMAP as amine,and reaction at 110℃ for 12 h.