| 摘要 |
NEW MATERIAL:A 2,5'-disubstituted-5,2'-bipyrimidinyl of formula I (ring A is formula II or III; X is F, Cl, Br, Cn; R is 1-10C alkyl, alkoxy). EXAMPLE:2-(p-Bromophenyl)-5'-pentyl-5,2'-bipyrimidinyl. USE:A liquidcrystal component that has markedly large positive dielectric anisotropy, makedly large diffractive anisotropy, a significantly wide range of liquidcrystal temperature, very high clear point and satisfactory stability to heat, light, temperature and electricity necessary for liquidcystal displays. PREPARATION:A compound of formula V is obtained from a compound of formula VI through 2 steps and the condensation cyclization between the compound of formula V (Y is F, Cl, Br) and a compound of formula VI is carried out in the presence of an appropriate base catalyst to give the compound of formula I (X is Y), when needed, the compound where Y is Br is cyanated with cupprous cyanide to give another compound of formula I where X is CN.
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