液晶材料反-4-[反-4-(3,4,5-三氟苯基)环己基]环己基-1-乙烯的合成

Synthesis of trans-4-[trans-4-(3,4,5-trifluorophenyl)cyclohexane]cyclohexane-1-ethylene liquid crystal compound

以3,4,5-三氟溴苯和单乙二醇缩4,4'-双环己基二酮为起始原料,经格氏反应、脱水、氢化、脱保、转型、Wittig反应、水解、转型和Wittig反应最终合成了标题化合物。其中酮的转型反应中选取20%(m(AlCl3)/m(顺式))量的AlCl3,反应时间1.5 h;脱水反应最佳溶剂选二甲苯,反应时间4 h。纯化后目标产物纯度99.5%,总收率约25%,其结构经IR,1 HNMR及MS确证。

Trans-4-[trans-4-（3,4,5-trifluorophenyl）cyclohexane]cyclohexane-1-ethylene liquid crystal compound was synthesized from 1-bromo-3,4,5-trifluorobenzene and 4,4′-dicyclohexanedione mono-ethylene ketal by Grignard reaction,dehydration,hydrogenation,deprotection,transconformation,Witting reaction,hydrolization,transconformation and Wittig reaction.The optimal conditions for the transformation of ketone were as follows.The amount of AlCl3 was 20%（m（AlCl3）/m（cis）） and the reaction time was 1.5 h.For dehydration,the best solvent was xylene and the reaction time was 4 h.The total yield and purity of the target compound was about 25% and 99.5%（GC）.The structure of compound was affirmed by IR,1HNMR and MS.