| 摘要 |
NEW MATERIAL:The compound of formula I [R is 1-9C n-alkyl; the cyclohexane ring is trans(equatorial-equatorial) configuration]. EXAMPLE:3,4-Difluorophenyl-trans-4-n-pentylcyclohexanecarboxylate of formula II. USE:An agent for lowering the threshold voltage of a liquid crystal material for electro-optical display. It has positive dielectric anisotropy and low viscosity, and can be used as a material for dynamic light-scattering display cell or field-effect cell. PREPARATION:The compound of formula I can be prepared by (1) reacting 3,4- difluoroaniline of formula III with sulfuric acid or hydrochloric acid to form a sulfate, etc., (2) reacting the salt with an aqueous solution of NaNO2, (3) decomposing the obtained diazonium salt in sulfuric acid to the compound of formula IV, and (4) reacting the compound with the compound of formula V in an inert organic solvent in the presence of a basic compound catalyst such as pyridine.
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