| 摘要 |
NEW MATERIAL:A compound of formula I (R is 1-8C alkyl; X and Y are halogen such as Br, Cl or F or H, provided that at least one thereof is halogen). EXAMPLE:5-Propyl-2-(4'-fluorophenylyl-4)pyrimidine. USE:One component in liqid crystal compositions, having a wide liquid crystal temperature range and +20 positive anisotropic value of dielectric constant, capable of reducing the threshold voltage of operation of the liquid crystal compositions by addition thereof, having improved compatibility with other liquid crystal compounds, hig clear point and useful as a liquid crystal component at high temperatures, etc. PREPARATION:A substituted benzonitritrnile of formula II is reacted with HCl gas in CH3OH solvent to form a compound of formula III, which is then reacted with NH3 gas in CH3OH solvent to give a compound of formula IV. The resultant compound of formula IV is condensed with an acrolein derivative of formula Vin the presence of a suitable base catalyst to afford the aimed compound of formula I .
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