| 摘要 |
NEW MATERIAL:A compound shown by formula I (R1 and R2 are 1-3C alkyl or CN; with the proviso that at least one of R1 and R2 is alkyl). USE:An electro-optical liquid crystal cell. A liquid crystal compound having an extremely wide nematic liquid crystal temperature range, an especially high transparent point and useful for enlarging a liquid crystal temperature range of another liquid crystal system by addition with a small amount. The existing pyridine ring induces the same effects as those of intermolecular mutual action of heterocyclic ring and improvement in electro-optical characteristics can be expected. PREPARATION:A compound shown by formula II is lithiated with n-butyllithium in dried benzene to form a compound shown by formula III, which is reacted with pyridine in dried diethyl ether and then reacted with a compound shown by the formula R4Br (R4 is 1-8C alkyl) in dried tetrahydrofuran and further hydrolyzed to give a compound shown by formula I when R2 is R4.
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