| 摘要 |
NEW MATERIAL:alpha-Halo-alkanoates expressed by formula I [R is 1-15C straight-chain or branched alkyl (optically active or nonoptically active in the case of branched alkyl); X is F, Cl or Br; A is formula II-IV, etc., (R' is 1-20C straight-chain or branched alkyl; Y is H, F, Cl, Br or CN); * indicates optically active carbon atom]. EXAMPLE:(2S,3S)-4'-Octyl-4-biphenylyl-2-chloro-3-methyl-pentanoate. USE:A liquid crystalline substance capable of imparting spontaneous polarization (Ps) to chiral or nonchiral smectic liquid crystal compositions and shortening time of response of ferroelectric liquid crystal display elements and preventing liquid crystals from forming reverse.twisted domains. PREPARATION:A compound expressed by formula V is diazotized in the presence of a hydrogen halide and substituted by a halogen. The resultant compound expressed by formula VI is esterified in the presence of a dehydration condensing agent to afford the aimed compound expressed by formula I.
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