| 摘要 |
NEW MATERIAL:5-Alkyl-2-(4'-alkylphenyl)pyrimidine of formula I (R1, R2 are 1- 10C alkyl). EXAMPLE:5-Propyl-2-(4'-benzylphenyl)pyrimidine. USE:A component for liquid crystal compositions: it has a large anisotropy in refractive index in comparison with its low viscosity, further high stability and compatibility. The addition of the compound increases response properties, contrast, sharpness and lowers the viscosity of the composition and the threshold voltage. PREPARATION:The cyclization reaction between 4-alkylphenylamidine hydrochloride of formula II and alkylmalonic diethyl ester of formula III is carried out in the presence of a catalyst of sodium methoxide to give a compound of formula IV, which is treated with POCl3 to effect chlorination into a compound of formula V. Then, the compound is reduced with hydrogen in the presence of a Pt/C catalyst to give the compound of formula I .
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