| 摘要 |
NEW MATERIAL:A compound expressed by formula I (R' is 1-10C alkyl; X' is halogen of F, Cl or Br; X'' is H or X'). EXAMPLE:4-(trans-4''-propylcyclhexyl-1''-ethyl)-4'-fluorotolan. USE:One component of a liquid crystal composition. The above-mentioned compound is a neomatic liquid crystal compound having low viscosity, has large anisotropy of refractive index and high N-I transition temperature and mixed with other component to provide a practical liquid crystal material. PREPARATION:A compound expressed by formula VII is reacted with a compound expressed by formula II in CS2 in the presence of AlCl3 to give a ketone derivative expressed by formula III, which is reacted with a reducing agent such as LiAlH4, in a solvent to afford a compound expressed by formula IV, which is subjected to dehydration in the presence of a catalyst such as paratoluene sulfonic acid, in an inert organic solvent to give a compound expressed by formula V, which is then subjected to addition reaction with Br2 in a solvent to provide a compound expressed by formula VI. The compound expressed by formula VI is reacted with potassium tert. butoxide to give the compound expressed by formula I.
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