含CF2 O桥键四氢吡喃液晶化合物的合成与性能

摘要

2[4′[difluoro (3,4,5trifluoro2methylphenoxy)methyl]-3′,5′difluoro [1,1′biphenyl]-4yl]-5alkyltetrahydropyran derivatives was synthesized via butyl lithium,dehydroxylation,Suzuki and Williamson reaction (five steps'reaction)by employing 1,4-Dibromo-benzene,5-alkyl-tetrahydro-py-ran-2-one and 3,4,5-Trifluoro-2-methyl-phenol as starting materials.The effects of reaction tempera-ture,solvent,catalyst and material ratio on the yield were investigated.The optimum reaction condi-tions for the Dehydroxylation reaction,the mole ratio of hydroxyl compounds,triethylsilane and boron trifluoride diethyl ether is 1 :1.5 :2.5 under the drop-temperature at -70 ~-80 ℃.For the Suzuki reaction,(beta-4)-platinum was the best catalysts.The optimum reaction condition for Wil-liamson etherification of 3,4,5-Trifluoro-2-methyl-phenol were 6 h in DMSO-water mixed solvent. After purification processing,the total yield was 35.6% with the purity was 99.5% (GC),the struc-ture was characterized by 1 H NMR and GC-MS.The addition of the compound into the basic formula of liquid crystal,could improve the dielectric anisotropy (Δε),and could reduce threshold voltage as well.%以对二溴苯、5-烷基-四氢吡喃-2-酮和3,4,5-三氟-2-甲基苯酚为原料,经过丁基锂反应、脱羟基、Suzuki和Williamson等共5步反应最终合成2[4′[二氟(3,4,5-三氟2-甲基苯氧基)甲基]-3′,5′-二氟-[1,1′联苯]-4-基]-5-烷基四氢吡喃类液晶化合物.反应中考察了温度、溶剂、催化剂和原料比对反应收率的影响.其中脱羟基反应滴加温度-70℃~-80℃,原料羟基化合物:三乙基硅烷:三氟化硼乙醚的摩尔比为1:1.5:2.5;Suzuki反应选用四(三苯基磷)钯反应收率最高;3,4,5-三氟-2-甲基苯酚的Williamson醚化最优条件为在DMSO与水的混合溶剂中醚化6 h.纯化后目标产物气相色谱纯度≥99.5%,总收率约为35.6%,结构经1 HNMR及GC-MS确证.该化合物添加到液晶的基础配方中,能增加介电各向异性(Δε),降低阈值电压.