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以3,4,5-三氟苯酚、3,5-二氟-4’-烷基联苯为原料,经酚羟基保护反应、丁基锂/碘甲烷上甲基反应、Williamson醚化反应等5步反应最终合成4-[二氟(3,4,5-三氟-2-甲基-苯氧基)甲基]-3,5-二氟-4’-烷基联苯类化合物。纯化后目标产物的气相色谱纯度≥99.5%,总收率约为47%,结构经~1HNMR及GC-MS确证。其中,合成2-(3,4,5-三氟-2-甲基-苯氧基)四氢吡喃适宜的物质的量比为n(2-(3,4,5-三氟苯氧基)四氢吡喃)∶n(丁基锂)=1∶1.2,3,4,5-三氟-2-甲基苯酚和4-溴二氟甲基-3,5-二氟-4’-烷基联苯醚化反应的最优化条件为在DMSO中反应4 h。将该化合物添加到液晶的基础配方中,能降低旋转粘度(γ1),提高液晶的响应速度,增加介电各向异性(Δε),降低阈值电压。
Using 3,4,5-trifluorophenol and 3,5-difluoro-4’-alkylbiphenyl as raw materials, phenolic hydroxyl protection reaction, butyl lithium / methyl iodide reaction, Williamson etherification reaction and the like The 5-step reaction finally resulted in the synthesis of 4- [difluoro (3,4,5-trifluoro-2-methyl-phenoxy) methyl] -3,5-difluoro-4’-alkylbiphenyl. Purification of the target product by GC purity ≥ 99.5%, the total yield of about 47%, the structure confirmed by ~ 1HNMR and GC-MS. Among them, the suitable molar ratio of synthesis of 2- (3,4,5-trifluoro-2-methyl-phenoxy) tetrahydropyran is n (2- (3,4,5-trifluorophenoxy Yl) tetrahydropyran): n (butyllithium) = 1: 1.2,3,4,5-trifluoro-2-methylphenol and 4-bromodifluoromethyl-3,5-difluoro-4 ’- alkyl biphenyl etherification reaction conditions in DMSO for 4 h. Adding this compound to the basic formulation of liquid crystal can reduce the rotational viscosity (γ1), increase the response speed of the liquid crystal, increase the dielectric anisotropy (Δε) and lower the threshold voltage.