2,5-Di:substd. 1,3-dioxan or pyrimidine derivs. - useful as components of liq. crystal media for electro-optical displays

摘要

2,5-Di-substd. heterocycles of formula (I) are claimed n = 1-10; Het = a gp. of formula (II), (III) or (IV): A = trans-1,4-cyclohexylene or (if Het = (IV), X = OCF3 or OCHF2 and/or Y = Z = F) 1,4-phenylene; X = CN, F, C1, CF3 or OCHF2; Y Z = H or F. X = F, Cl, CF3 or OCF3; Y = Z = H or Y = Z = H, or Y = F and Z = H or F. (I) are obtd by standard methods (e.g. reaction of substd. phenylcyclohexane-carboxaldehyde with a diol to give the 1.3-dioxan type, reaction of the corresp. amidine (via the corresp. acid and nitrilel with alpha-alkyl-beta-)dialkylaminoacrolein to give the pyrimidine type. e.tc, USE/ADVANTAGE; (I) are useful as components of liq. crystal media for electro-optical displays (claimed); also claimed are; such liq. crystalline media with at least 2 liq. crystal components, at least one of which is a cpd. (I) and electro-optical displays based on liq. crystal cells contg. such media. Media contg (I) have a broad nematic range, excellent nematogenicity at low temp., excellent chemical stability. pronounced epsilon-normal at high positive dielectric anisotropy. etc.,