| 摘要 |
NEW MATERIAL:A compound of formula I [R is 1-9C n-alkyl; the configuration of the cyclohexane is trans(equatorial-equatorial)]. USE:An electro-optical display material: it is a nematic liquid crystal with positive dielectric anisotropy. The mixing of the substance with a liquid crystal composition lowers the viscosity and threshold voltage with high compatibility. PREPARATION:The compound of formula III is formed from a compound of formula II and acetyl chloride and converted into a compound of formula IV by reaction with sodium hypochlorite in a sodium hydroxide solution. Then, the product is hydrogenated and acidified to liberate the free acid, which is subjected to thermal rearrangement to give a compound of formula V. The compound of formula V is allowed to react with thionyl chloride to give a compound of formula VI, finally the product is allowed to react with 3,4-difluorophenol in the presence of pyridine to give the compound of formula I .
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