Abstract: Compounds of the formula ##STR1## wherein X.sup.1 denotes fluorine or chlorine and X.sup.2 denotes hydrogen, fluorine or chlorine; R.sup.1 is 3E-alkenyl, 4-alkenyl, 2E-alkenyloxy or 3-alkenyloxy; n stands for the number 0 or 1; one of the groups Y.sup.1 and Y.sup.2 is a single covalent bond, --COO--, --OOC--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O-- or --OCH.sub.2 -- and the other of the groups Y.sup.1 and Y.sup.2 is a single covalent bond; and rings A.sup.1 and A.sup.2 each individually are substituted or unsubstituted trans-1,4-cyclohexylene, in which optionally 2 non-adjacent CH.sub.2 groups are replaced by oxygen, or substituted or unsubstituted 1,4-phenylene, in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; with the proviso that X.sup.2 denotes fluorine or chlorine and/or Y.sup.1 or Y.sup.2 denotes --CH.sub.2 O-- or --OCH.sub.2 -- when simultaneously X.sup.1 is fluorine and R.sup.1 is 3E-alkenyl,and their use for liquid crystalline mixtures and electro-optical purposes.

Abstract: Compounds of the formula ##STR1## wherein X.sup.1 denotes fluorine or chlorine and X.sup.2 denotes hydrogen, fluorine or chlorine; R.sup.1 is 3E-alkenyl, 4-alkenyl, 2E-alkenyloxy or 3-alkenyloxy; n stands for the number 0 or 1; one of the groups Y.sup.1 and Y.sup.2 is a single covalent bond, --COO--, --OOC--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O-- or --OCH.sub.2 -- and the other of the groups Y.sup.1 and Y.sup.2 is a single covalent bond; and rings A.sup.1 and A.sup.2 each individually are substituted or unsubstituted trans-1,4-cyclohexylene, in which optionally 2 non-adjacent CH.sub.2 groups are replaced by oxygen, or substituted or unsubstituted 1,4-phenylene, in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; with the proviso that X.sup.2 denotes fluorine or chlorine and/or Y.sup.1 or Y.sup.2 denotes --CH.sub.2 O-- or --OCH.sub.2 -- when simultaneously X.sup.1 is fluorine and R.sup.1 is 3E-alkenyl,and their use for liquid crystalline mixtures and electro-optical purposes.

Abstract: Compounds of the formula ##STR1## wherein X.sup.1 denotes fluorine or chlorine and X.sup.2 denotes hydrogen, fluorine or chlorine; R.sup.1 is 3E-alkenyl, 4-alkenyl, 2E-alkenyloxy or 3-alkenyloxy; n stands for the number 0 or 1; one of the groups Y.sup.1 and Y.sup.2 is a single covalent bond, --COO--, --OOC--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O-- or --OCH.sub.2 -- and the other of the groups Y.sup.1 and Y.sup.2 is a single covalent bond; and rings A.sup.1 and A.sup.2 each individually are substituted or unsubstituted trans-1,4-cyclohexylene, in which optionally 2 non-adjacent CH.sub.2 groups are replaced by oxygen, or substituted or unsubstituted 1,4-phenylene, in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; with the proviso that X.sup.2 denotes fluorine or chlorine and/or Y.sup.1 or Y.sup.2 denotes --CH.sub.2 O-- or --OCH.sub.2 -- when simultaneously X.sup.1 is fluorine and R.sup.1 is 3E-alkenyl,and their use for liquid crystalline mixtures and electro-optical purposes.

Abstract: A ferroelectric liquid crystal mixture containing at least one compound of the formula ##STR1## wherein n stands for the number 0 or 1; X.sup.1 represents a single covalent bond, --COO-- or --OOC-- and X.sup.2 represents a single covalent bond, --COO--, --OOC--, --CH.sub.2 CH.sub.2 --, --OCH.sub.2 -- or --CH.sub.2 O--; rings A.sup.1, A.sup.2 and A.sup.3 each independently signify 1,4-phenylene optionally substituted with cyano, halogen or lower alkyl or pyrimidin-2,5-diyl, pyrazin-2,5-diyl, when n is 1, trans-1,4-cyclohexylene or trans-m-dioxan-2,5-diyl; with the proviso that one of the rings present stands for pyrimidin-2,5-diyl or pyrazin-2,5-diyl when a further ring signifies trans-1,4-cyclohexylene or when n stands for the number 0 and X.sup.1 stands for a single covalent bond; and R.sup.1 signifies an optionally halogen-substituted alkenyl group with up to 18 carbon atoms in which optionally 1 or 2 non-adjacent CH.sub.2 groups are replaced by --O-- and/or a C.dbd.C double bond; with the proviso that R.

Abstract: Compounds of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are independently straight-chain C.sub.1 -C.sub.12 -alkyl or when positioned on an aromatic ring R.sup.1 and R.sup.2 may also independently be straight-chain C.sub.1 -C.sub.12 -alkoxy, or one of R.sup.1 and R.sup.2 may also be a group of the formula: ##STR2## X.sup.1 and X.sup.2 are independently single covalent bonds or one of X.sup.1 and X.sup.2 may also be --CH.sub.2 CH.sub.2 --; rings A.sup.1 and A.sup.2 are independently 1,4-phenylene or, when X.sup.1 or X.sup.2 is --CH.sub.2 CH.sub.2 --, rings A.sup.1 and A.sup.2 may also independently be trans-1,4-cyclohexylene; and R.sup.3 is straight-chain C.sub.1 -C.sub.12 -alkyl or when positioned on an aromatic ring R.sup.3 may also be straight-chain C.sub.1 -C.sub.12 -alkoxy. Their manufacture and use in liquid crystalline mixtures are described.

Abstract: Compounds of the formula ##STR1## wherein R.sup.1 is hydrogen or straight-chain alkyl; R.sup.2 is --CN, --R, --COR, --COOR or when R.sup.2 is positioned on an aromatic ring R.sup.2 also can be --OR, --OOCR or --F; R is alkyl; A is a group with 1 to 4 six-membered rings, these rings being linked directly with one another and with ring B in each case via a single covalent bond or being linked at one or two positions also via --COO--, --OOC-- or --CH.sub.2 CH.sub.

Abstract: A liquid crystalline mixture comprising(a) at least one compound of the formula: ##STR1## wherein R.sup.1 is alkyl, alkoxy, p-alkylphenyl, p-alkoxyphenyl, trans-4-alkylcyclohexyl, 4'-alkyl-4-biphenylyl, p-(trans-4-alkylcyclohexyl)phenyl, 2-(trans-4-alkylcyclohexyl)ethyl or p-[2-(trans-4-alkylcyclohexyl)ethyl]phenyl and R.sup.2 is trans-4-alkylcyclohexyl; or R.sup.1 is trans-4-alkylcyclohexyl and R.sup.2 is p-(trans-4-alkylcyclohexyl)phenyl, p-[2-(trans-4-alkylcyclohexyl)ethyl]phenyl or 4'-(trans-4-alkylcyclohexyl)-4-biphenylyl; or R.sup.1 is p-alkylphenyl and R.sup.2 is p-[2-(trans-4-alkylcyclohexyl)ethyl]phenyl; and the alkyl and alkoxy groups in the substituents R.sup.1 and R.sup.2 are straight-chain groups of 1 to 7 carbon atoms, and;(b) at least one dichroic coloring substance selected from the group of compounds consisting of: ##STR2## wherein R.sup.3 is straight-chain C.sub.1 -C.sub.12 -alkyl and R.sup.4 is straight-chain C.sub.1 -C.sub.4 -alkyl, Z.sup.1 is hydrogen or chlorine, one of the symbols Z.

Abstract: Pyrimidines of the formula: ##STR1## wherein Y is nitrogen and Z is .dbd.CH--, or Z is nitrogen and Y is .dbd.CH--; R.sup.1 is alkyl and R.sup.2 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 C.sub.2 H.sub.5 --CH(CH.sub.3)--(CH.sub.2).sub.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 14are described. Liquid crystalline mixtures comprising Compound I as well as their use in electro-optical devices also are disclosed.

Abstract: Liquid crystal mixtures containing a coloring substance which comprise about 5 to about 40 weight % of trans-p-[5-(4-alkylcyclohexyl)-2-pyrimidinyl]benzonitriles, about 10 to about 60 weight % of trans-4-alkylcyclohexane carboxylic acid phenyl esters and about 0.1 to about 15 weight % of one or more coloring substances of the formula ##STR1## wherein m stands for the number 1 and X is alkoxy and Y is nitro; or m stands for the number 1 or 2; and X is p-alkoxyphenyl and Y is nitro or dialkylamino, or X is alkoxy and Y is -p-nitrophenyl or -(dialkylamino)phenyl; or m stands for the number 2, and X is alkoxy and Y is alkoxy, nitro or dialkylamino, or both X and Y are dialkylamino; and wherein the alkoxy denotes a straight-chain group containing 1 to 12 carbon atoms and the alkyl groups in the dialkylamino each denote a straight-chain alkyl group containing 1 to 4 carbon atoms are described.

Abstract: Compounds of the formula ##STR1## wherein ring A is saturated or aromatic and a saturated ring A which may be present is trans-linked with the second ring; R.sup.1 is a straight-chain alkyl or alkoxy group containing 1 to 11 carbon atoms; R.sup.2 is cyano, a straight-chain alkyl group containing 1 to 11 carbon atoms, an ester group of the formula ##STR2## or, when ring A is saturated, additionally a straight-chain alkoxy group containing 1 to 11 carbon atoms; in the ester group of formula II ring B is either aromatic and X is oxygen or sulfur and R.sup.3 is cyano or a straight-chain alkyl or alkoxy group containing 1 to 10 carbon atoms, or ring B is a trans-1,4-disubstituted cyclohexane ring and X is oxygen and R.sup.3 is cyano or a straight-chain alkyl group containing 1 to 10 carbon atoms; and the total number of carbon atoms in the alkyl and/or alkoxy groups amounts to at most 12, are described. The compounds of formula I are useful in liquid crystal mixtures.

Abstract: Pyrimidine derivatives of the formula ##STR1## wherein at least one of rings A and B is a trans-1,4-disubstituted cyclohexane ring and the other, optionally, may be aromatic and R is straight-chain alkyl or alkoxy of 1 to 10 carbon atoms or a branched-chain alkyl group of the formula C.sub.2 H.sub.5 --CH(CH.sub.3)--(CH.sub.2).sub.n -- wherein n is 1, 2 or 3, are described. Processes for the preparation of the compounds of formula I as well as their uses in liquid crystalline mixtures are also described.

Abstract: Liquid crystalline mixtures comprising trans-phenyldioxane, phenylpyrimidine and phenylbenzoate compounds which are useful in electro-optical apparatuses are disclosed.

Abstract: Optically active pyrimidines of the formula ##STR1## wherein Z is --(CH.sub.2).sub.n -- or --(CH.sub.2).sub.n --O-- wherein n is an integer of 1 to 4 and each of the symbols X is a nitrogen atom and each of the symbols Y is --CH-- or each of the symbols Y is a nitrogen atom and each of the symbols X is --CH--,useful for electro-optical purposes, as well as liquid crystalline mixtures for electro-optical purposes containing compounds of the formula Ia and/or Ib, are described.The compounds of formulas Ia and Ib are useful for electro-optical purposes, for example, in electro-optical apparatuses.

Abstract: Pyrimidine derivatives of the formula ##STR1## wherein at least one of rings A and B is a trans-1,4-disubstituted cyclohexane ring and the other, optionally, may be aromatic and R is straight-chain alkyl or alkoxy of 1 to 10 carbon atoms or a branched-chain alkyl group of the formulas C.sub.2 H.sub.5 --CH(CH.sub.3)--(CH.sub.2).sub.n --wherein n is 1, 2 or 3, are described. Processes for the preparation of the compounds of formula I as well as their uses in liquid crystalline mixtures are also described.

Abstract: Liquid crystal mixtures having positive anisotropy of the dielectric constants comprising a nematogenic material having a clearing point above 60.degree. C., one or more compounds of the formula ##STR1## wherein R.sub.1 and R.sub.2 are hydrogen or straight-chain alkyl, provided that at least one of R.sub.1 and R.sub.2 is other than hydrogen and that R.sub.1 and R.sub.2 together contain no more than 9 carbon atoms,and, if desired, one or more additional doping agents, are described.

Abstract: Liquid crystal mixtures having positive anisotropy of the dielectric constants which comprise a nematogenic mixture with a clearing point above 60.degree. C. which is doped with an organic solvent or solvent mixture with a specific resistance of at least 10.sup.7 Ohm.cm. as well as a dipole moment along the longitudinal axis of the molecule of less than 3.5 Debye, or with a compound of the formula ##STR1## wherein R.sub.14 and R.sub.15 are straight-chain alkyl containing a total of not more than 14 carbon atoms or R.sub.14 is straight-chain alkyl and R.sub.15 is straight-chain alkoxy containing a total of not more than 8 carbon atoms,or a compound of the formula ##STR2## wherein R.sub.16 and R.sub.17 are straight-chain alkyl containing a total of not more than 6 carbon atoms,or a compound of the formula ##STR3## wherein R.sub.16 and R.sub.17 are straight-chain alkyl containing a total of not more than 6 carbon atoms,or mixtures thereof, are described.

Abstract: Phenyl-pyrimidines of the formula ##STR1## wherein R.sub.1 and R.sub.2 are as hereinafter set forth, are described. The end products are useful as liquid crystals.

Abstract: Compounds of the formula ##STR1## wherein when X is nitrogen, Y and Z are --CH--; or when Y is nitrogen, X and Z are --CH--; or when Z is nitrogen, X and Y are --CH--; and one of R.sub.1 and R.sub.2 is cyano and the other is straight-chain alkyl of 1 to 7 carbon atoms, straight-chain alkoxy of 1 to 7 carbon atoms or straight-chain alkanoyloxy of 2 to 7 carbon atoms,Prepared by a variety of methods, are described. The compounds of the invention are useful as components of nematic mixtures.

Abstract: Liquid crystalline alkylcinnamic acid p'-cyanophenyl esters, useful, for example, for electro-optical purposes, are described.

Abstract: Liquid crystal substances or compounds of the formula ##STR1## wherein R is as hereinafter set forth, as well as compositions and electro-optical apparatuses containing them are described.