1=Phenyl-2=pyridyl- and pyrimidyl-acetylene(s) useful in liquid crystal media

摘要

Pyri(mi)dine derivs. of formula (I) are new: R = alk(en)yl with up to 15C, opt. mono-substd. by CN, halogen or CF3, in which 1 or more -CH2- gps. may be replaced by -O-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, without directly linked O atoms; ring A = (a) trans-1,4-cyclohexylene (cyc), in which 1 or more non-adjacent -CH2- gps. may be replaced by -O- and/or -S-; (b) 1,4-phenylene (PHe), in which 1 or 2 CH gps. may be replaced by N; or (c) 1,4-cyclohexylene, 1,4-bicyclo-(2.2.2)octylene, piperidin-1,4-diyl, naphtha-2,6-diyl, deca:hydrogen:naphtha-2,6-diyl or 1,2,3,4-tetra:hydro:naphtha-2,6-diyl; and the (a) and (b) gps. may be mono- or di-substd. by F; X = 1-10C alkyl or alkoxy or Q-Y; Q = -O-, -S- or a single bond; Y = H, F, Cl, Cn or a mono- or poly-halo-alk(en)yl gp. with up to 10C; Z = N or CH; L<1>,L<2> = H or F; m = 0, 1 or 2. Also claimed are liquid crystal (LC) media contg. cpd(s). (I), LCD elements contg. this medium and electrooptical display elements contg. the medium as dielectric.