Disubstituted pyrimidines

摘要

Pyrimidines of the formula: <IMAGE> I Wherein Y is nitrogen and Z is =CH-, or Z is nitrogen and Y is =CH-; R1 is alkyl and R2 is cyano, alkyl, p-alkylphenyl or trans-4-alkylcyclohexyl; where each alkyl denotes either a straight chain alkyl group of 1 to 12 carbon atoms or a branched chain alkyl group of the formula C2H5-CH(CH3)-(CH2)n, n is 1, 2 or 3; with the proviso that the compound contains at most only one of said branched chain alkyl group and with the further proviso that the sum of the carbon atoms in all of the alkyl groups within the compound is at most 14 are described. Liquid crystalline mixtures comprising Compound I as well as their use in electro-optical devices also are disclosed.