DE3631611A1 - Hydroterphenyls - Google Patents

Abstract

Hydroterphenyls of the formula I R<1>-Cy-Cy-Z-Ph-R<2> in which R<1> represents alkyl, R<2> represents H, F, Cl, Br, I, OH, CN, NCS, alkyl, -O-alkyl, -COOR<3> or -O-CO-R<3>, Z represents -COO- or a single bond, R<3> represents H, alkyl, -Cy-alkyl, -Ph-alkyl, -Ph-O-alkyl, -Ph-CN or -Ph-F, Cy represents 1,4-cyclohexylene, Ph represents 1,4-phenylene or 1,4-phenylene which is substituted in the 2- or 3-position by fluorine, and alkyl represents an alkyl group having 1-10 C atoms, in which one or more non-adjacent CH2 groups which are not linked by -O- or Ph can also be replaced by -O- and/or -CH=CH-, with the proviso that at least one CH2 group in at least one alkyl group in R<1> and/or R<2> is replaced by -O- or -CH=CH-, can be used as components of liquid-crystalline phases for electro-optical display elements.

Description

The invention relates to new hydroterphenyls of the formula I.

R ¹ -Cy-Cy-Z-Ph-R ² (I)

wherein

R ¹ alkyl, R ² H, F, Cl, Br, J, OH, CN, NCS, alkyl, -O-alkyl, -COOR ³ or -O-CO-R ³ , Z-COO- or a single bond, R ³ H, alkyl, -Cy-alkyl, -Ph-alkyl, -Ph-O-alkyl, -Ph-CN or -Ph-F, Cy1,4-cyclohexylene, Ph1,4-phenylene or in 2- or 3- Position substituted by fluorine-substituted 1,4-phenylene, and alkyl means an alkyl group with 1-10 C atoms, in which also one or more non-adjacent and not linked to -O- Ph CH ₂ groups by -O- and / or -CH = CH- can be replaced, with the proviso that in at least one alkyl group in R ¹ and / or R ² at least one CH ₂ group is replaced by -O- or -CH = CH-.

These substances can, like similar, e.g. B. from the DE-OS 32 11 601 known compounds as components liquid crystalline phases are used, in particular for displays based on the principle of the twisted cell are based.

The invention was based, new stable task to find liquid crystalline compounds which as Components of liquid crystalline phases are suitable especially for nematic phases with a broad nematic Range, low melting point, favorable elastic constants and low viscosity. These The task was to provide the connections of formula I solved.

It has been found that the compounds of the formula I excellent as components of liquid crystalline phases are suitable. In particular, they are stable with their help liquid crystalline phases with low melting point, favorable elastic constants and low viscosity producible.

With the provision of the compounds of formula I will also generally the range of liquid crystalline Substances that can be found under various application technology Aspects of making nematic Mixtures are suitable, considerably widened.

The compounds of formula I have a wide range of applications. Depending on the choice of the substituents, these compounds can serve as base materials from which liquid-crystalline phases are predominantly composed; However, it is also possible to add compounds of the formula I to liquid-crystalline base materials from other classes of compounds, for example in order to reduce the viscosity of such a phase. The compounds of the formula I, in particular those in which R ^{2 is} H, Cl, Br, I, OH, CN or COOH, are also suitable as intermediates for the preparation of other substances which can be used as constituents of liquid-crystalline phases.

The compounds of the formula I are colorless in the pure state and form liquid crystalline mesophases in one for the electro-optical use of the conveniently located temperature range. Chemically they are very stable.

The invention thus relates to the compounds of the formula I and to a process for their preparation, characterized in that a compound corresponding to the formula I which, however, contains (a) reducible group (s) and / or additional CC bonds instead of hydrogen atoms , treated with a reducing agent and, if appropriate, converting the radical R ² into another radical R ² in a compound of the formula I obtained.

The invention furthermore relates to the use of the compounds of formula I as components of liquid crystalline Phases. The subject of the invention are still liquid-crystalline phase with a content on at least one compound of the formula I and electro-optical display elements, such phases contain.  

R ¹ , R ² , R ³ , Cy and Ph have the meaning given above and below, unless expressly stated otherwise.

Z is preferably a single bond. Also preferred are compounds in which Z is -CO-O- and R ^{2 is} fluorine.

Ph is preferably 1,4-phenylene. Also preferred are compounds of the formula I in which Ph is 1,4-phenylene substituted by fluorine in the 2- or 3-position and R ^{2 is} CN or F, particularly preferably F.

If the alkyl group in which at least one CH ₂ group is replaced by -O- or -CH = CH- is identical to R ¹ , the CH ₂ group linked to Cy is preferably not replaced. Preferred compounds of the formula I contain a straight-chain alkyl group in which a CH ₂ group has been replaced by -O-, particularly preferably a group of the formula - (CH ₂ ) _p -OC _q H _{2 q + 1} , in which p is preferably 1 or 2 , particularly preferably 1 and q is 1 to 7, in particular 1 to 4.

The compounds of the formula I include, for example, the preferred compounds of the formula I 'which corresponds to the formula I, but in which the radical R ^{2 is} H, OH, CN, alkyl, -O-alkyl, -COOR ³ or -O-CO-R ³ means, furthermore in particular the preferred nitriles of the formula Ia, furthermore the preferred hydrocarbons of the formula Ib, ethers of the formula Ic, halogen compounds of the formula Id and isothiocyanates of the formula Ie:

R ¹ -Cy-Cy-Z-Ph-CN (Ia)
R ¹ -Cy-Cy-Z-Ph-alkyl (Ib)
R ¹ -Cy-Cy-Z-Ph-O-alkyl (Ic)
R ¹ -Cy-Cy-Z-Ph-Hal (Id)
R ¹ -Cy-Cy-Z-Ph-NCS (Ie)

where Hal is F, secondarily Cl, Br or J.

Formula I also includes the as Intermediates important hydroterphenyl derivatives of Formulas Ie and If and the esters of formulas Ig and Ih:

R ¹ -Cy-Cy-Z-Ph-H (Ie)
R ¹ -Cy-Cy-Z-Ph-OH (If)
R ¹ -Cy-Cy-Z-Ph-COOR ³ (Ig)
R ¹ -Cy-Cy-Z-Ph-O-CO-R ³ (Ig)

In the compounds of formula I and Ia to Ih those stereoisomers preferred in which the substituents on the two 1,4-cyclohexylene residues in each case are in the trans position to each other.

In the compounds of the formula I, the alkyl or O-alkyl radicals, in which one or more non-adjacent CH ₂ groups which are not linked to -O- or Ph can also be replaced by -O- and / or -CH = CH- can be straight-chain or branched.

They are preferably straight-chain, have 2, 3, 4, 5 or 6 carbon atoms and are preferably ethyl, propyl, Butyl, pentyl, hexyl, ethoxy, propoxy, butoxy, pentoxy, Hexoxy, methoxymethyl, ethoxymethyl, propoxymethyl, Butoxymethyl, pentoxymethyl, methoxyethyl, ethoxyethyl, Propoxyethyl, methoxypropyl, ethoxypropyl, methoxybutyl, 1,3-dioxabutyl (= methoxymethoxy), 1,3- 1,4- or 2,4-dioxapentyl, 1,3-, 1,4-, 1,5-, 2,4-, 2,5- or 3,5-dioxahexyl, vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, allyloxy, 2-butenyloxy, furthermore methyl, heptyl, Octyl, nonyl, decyl, methoxy, heptoxy, octoxy, nonoxy, Decoxy, hexoxymethyl, heptoxymethyl or octoxymethyl.

Compounds of the formulas I and Ia to Ih with branched wing groups R ¹ or R ² can occasionally be of importance because of their better solubility in the customary liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Branched groups of this type usually contain no more than one chain branch. Preferred branched radicals R ¹ and R ² are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2 -Ethylhexyl, 2-heptyl (= 1-methylhexyl), 2-octyl (= 1-methylheptyl), 2-ethylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy , 2-ethylhexoxy, 1-methylhexoxy, 1-methylheptoxy.

R ¹ is preferably alkyl, in which a CH ₂ group which is not linked to Cy is replaced by -O- or -CH = CH-, particularly preferably by -O-, and R ^{2 is} F, CN, alkyl or -O-alkyl ( each with a straight-chain alkyl chain with 1-10 C atoms).

Also preferred are compounds of the formula I in which R ^{2 is} alkyl or -O-alkyl, where alkyl is an alkyl group having 1-10 C atoms, in which a CH ₂ group which is not linked to -O- Ph by -O- or -CH = CH-, particularly preferably replaced by -O-, and R ¹ denotes straight-chain alkyl having 1-10 C atoms.

The -CH = CH group can be cis- or trans-substituted be, preferably trans.

The compounds of formula I are per se known methods, as used in the literature (e.g. in the standard works such as Houben-Weyl, methods of organic chemistry, Georg-Thieme-Verlag, Stuttgart) are described, namely under reaction conditions, known and suitable for the above-mentioned implementations are. You can also from well-known, here make use of variants not mentioned in more detail.

If desired, the starting materials can also be in situ are formed such that they can be removed from the reaction mixture not isolated, but immediately to the Reacts compounds of formula I.

The compounds of formula I are preferred prepared by using a compound of formula II

wherein either
R ³ OH and R ⁴ or
R ³ and R ⁴ together represent a CC bond,
reduced.

The carbinols of the formula II (R ³ = OH, R ⁴ = H) can be obtained, for example, by hydrogenation of cyclohexylphenols of the formula R ¹ -Cy-Ph-OH to cyclohexylcyclohexanols of the formula R ¹ -Cy-Cy-OH, Oxidation to the corresponding 4-R ¹ -Cy-cyclohexanones, reaction with a Grignard compound of the formula BrMg-Ph-R ² and hydrolysis. By dehydration, e.g. B. with a strong acid such as sulfuric acid or p-toluenesulfonic acid in an inert solvent such as benzene or toluene, the cyclohexenes of the formula II (R ³ and R ⁴ together = CC bond) can be prepared.

The reduction of the starting materials of formula II to Compounds of formula I are advantageously carried out by catalytic hydrogenation at temperatures between about 0 ° and about 200 ° and pressures between about 1 and 200 bar in an inert solvent, e.g. B. one Alcohol such as methanol, ethanol or isopropanol, one Ethers such as tetrahydrofuran (THF) or dioxane, one Esters such as ethyl acetate, a carboxylic acid such as acetic acid or a hydrocarbon such as cyclohexane.

Suitable catalysts are suitably noble metals such as Pt or Pd, which are in the form of oxides (e.g. PtO ₂ , PdO), on a support (e.g. Pd on carbon, calcium carbonate or strontium carbonate) or in finely divided form (e.g. B. Pt-Mohr) can be used.

After the reduction stage, it may be advisable the stereoisomer mixture obtained into the stable trans isomers (based on the hydrogenation obtained cyclohexane ring), z. B. by Treat with a base such as K-tert-butoxide in an inert solvent such as dimethylformamide (DMF), N-methylpyrrolidone or dimethyl sulfoxide at temperatures between about 0 and about 150 °.

If desired, the radical R ^{2 can be converted} into another radical R ² in a compound of the formula I obtained.

Chlorination or bromination of the hydroterphenyls of the formula Ie leads to chlorine or bromine compounds of the formula I (R ² = Cl or Br), for example using elemental chlorine or bromine in an inert solvent such as diethyl ether, CCl ₄ or acetic acid at temperatures between about -30 and 100 °, where catalysts such as iron filings, iodine or AlCl ₃ may be present.

By reacting these chlorine or bromine compounds with Cu ₂ (CN) ₂ , e.g. B. in the presence of pyridine in an inert solvent such as DMF or N-methylpyrrolidone at temperatures between 40 and 200 °, nitriles of the formula Ia are available.

Furthermore, hydroterphenyls of the formula Ie (I, R ² = H) can be converted into ketones of the formula by acylation with carboxylic acids of the formula HOOC-R ⁵ (in which R ^{5 is} alkyl with 1-9 C atoms) or their reactive derivatives

R ¹ -Cy-Cy-Ph-CO-R ⁵

be transferred, advantageously in the presence of an acid catalyst and an inert solvent at temperatures between about 0 ° and about 120 °. Suitable derivatives of carboxylic acids are primarily their anhydrides and halides, e.g. B. the corresponding acid chlorides and acid bromides. Suitable catalysts are acids such as HF, H ₃ PO ₄ or polyphosphoric acid or, preferably, Lewis acids such as AlCl ₃ , AlBr ₃ , SnCl ₄ , ZnCl ₂ , FeCl ₃ , SbCl ₅ , BF ₃ or its etherate, as a solvent, for. B. CS ₂ , hydrocarbons such as hexane, halogenated hydrocarbons such as dichloromethane, nitrobenzene or tetramethylene sulfone.

The ketones mentioned can be oxidized to carboxylic acids of the formula I (R ² = COOH), for. B. with hypohalite, conveniently generated in situ from bromine and a base such as NaOH in aqueous dioxane at temperatures between about 0 and about 50 °.

The carboxylic acids of formula I (R ² = COOH) can be used in a conventional manner, e.g. B. with SOCl ₂ , or PCl ₅ at temperatures between about 0 and 100 °, in the corresponding acid chlorides and these with ammonia, for. B. in aqueous dioxane at temperatures between about 0 and 30 °, in the corresponding acid amides of the formula

R ¹ -Cy-Cy-Ph-CONH ₂

be transferred.

Dehydration of these amides leads to the nitriles of the formula Ia. Suitable water-releasing agents are, for example, inorganic acid chlorides such as SOCl ₂ , PCl ₃ , POCl ₅ , PCl ₅ , SO ₂ Cl ₂ , COCl ₂ , furthermore P ₂ O ₅ , P ₂ S ₅ , AlCl ₃ (e.g. as a double compound with NaCl), aromatic sulfonic acids and sulfonic acid halides. You can work in the presence or absence of an inert solvent at temperatures between about 20 and 150 °; come as a solvent, for. B. aromatic hydrocarbons such as benzene, toluene or xylene or amides such as DMF into consideration.

Hydrocarbons of the formula Ib are e.g. B. available by reducing the ketones of the formula mentioned

R ¹ -Cy-Cy-Ph-CO-R ⁵

according to Clemmensen's methods (with zinc, amalgamated zinc or tin and Hydrochloric acid, suitably in aqueous-alcoholic solution or in heterogeneous phase with water / benzene or Water / toluene at temperatures between about 80 and 120 °) or Wolff-Kishner (with hydrazine, convenient in Presence of alkali such as KOH or NaOH in a high-boiling Solvents such as diethylene glycol or triethylene glycol at temperatures between about 100 and 200 °). The Ketones can also be catalytically listed below Conditions for the hydrocarbons of the formula Ib are hydrogenated, preferably over a Pt or Pd catalyst at temperatures between 20 and 80 ° normal pressure in one of the solvents mentioned, e.g. B. THF.

Implementation of the ketones mentioned with hydroxylamine, for. B. in aqueous ethanol in the presence of a base such as KOH or pyridine at temperatures between about 20 and 100 °, provides the corresponding oximes, which under the conditions of a Beckmann rearrangement, for. B. with PCl ₅ or formic acid at temperatures between about 20 and 100 °, in the corresponding amides of the formula

R ¹ -Cy-Cy-Ph-NH-CO-R ⁵

converted can be. Hydrolysis, e.g. B. with aqueous mineral acids such as sulfuric acid or hydrochloric acid at temperatures between about 20 and 150 ° leads to the corresponding Amides of the formula

R ¹ -Cy-Cy-Ph-NH ₂ .

This can also be done by Nitration of the hydrocarbons of the formula Ie and subsequent reduction of the nitro compounds obtained formula

R ¹ -Cy-Cy-Ph-NO ₂

are produced, for example by hydrogenation under the conditions specified above, or by chemical means, for. B. with nascent hydrogen, which can be generated with the systems Fe / HCl, Zn / HaOH, Zn / CH ₃ COOH or Sn / HCl, with SnCl ₂ / HCl, with H ₂ S or sulfides or with Na ₂ S ₂ O _4th

Phenols of the formula If are z. B. by diazotization of the amides and subsequent boiling. You can, as usual, diazotize with a salt or an ester of nitrous acid (such as NaNO ₂ or butyl nitrite) in an acidic aqueous medium and then decompose the diazonium salt solution obtained by hydrolysis at temperatures between about 50 and 150 °.

Alkoxy compounds of the formula Ic can be obtained by alkylating the phenols of the formula If, the phenol expediently first in a phenolate, for. B. is converted into the corresponding alkali metal phenolate by treatment with NaOH, KOH, Na ₂ CO ₃ or K ₂ CO ₃ . This can then be reacted with the corresponding alkyl halide, sulfonate or dialkyl sulfate, advantageously in an inert solvent such as acetone, DMF or dimethyl sulfoxide or else an excess of aqueous or aqueous alcoholic NaOH or KOH at temperatures between about 20 and 100 °.

Esters of the formula I (in which Z is -CO-O-) or in the formula Ig (in which R ^{3 is} different from H) and Ih can also be obtained by esterification of carboxylic acids, for. B. the formula I (R ² = COOH) (or its reactive derivatives) with alcohols or phenols z. B. of the formula HO-R ³ (or their reactive derivatives) or of phenols of the formula If (or their reactive derivatives) with carboxylic acids of the formula HOOC-R ³ (or their reactive derivatives).

As reactive derivatives of the carboxylic acids mentioned the acid halides are particularly suitable the chlorides and bromides, furthermore the anhydrides, e.g. B. also mixed anhydrides of the formulas

R ¹ -Cy-Cy-Ph-CO-O
COCH ₃ or R ³ -CO-O-COCH ₃ ,

Azides, esters, in particular Alkyl esters with 1-4 C atoms in the alkyl group.  

As reactive derivatives of the alcohols mentioned or Phenols come especially the corresponding ones Metal alcoholates or phenolates of the formulas

MO-R ³ or
R ¹ -Cy-Cy-Ph-OM

into consideration where M is an equivalent a metal, preferably an alkali metal such as Na or K means.

The esterification is advantageous in the presence of a inert solvent performed. Are well suited in particular ethers such as diethyl ether, di-n-butyl ether, THF, dioxane or anisole, ketones such as acetone, butanone or Cyclohexanone, amides such as DMF or phosphoric acid hexamethyltriamide, Hydrocarbons such as benzene, toluene or xylene, Halogenated hydrocarbons such as carbon tetrachloride or Tetrachlorethylene and sulfoxides such as dimethyl sulfoxide or Sulfolan. Solvents immiscible with water can at the same time advantageous for azeotropic distillation of the water formed during the esterification will. Occasionally, an excess of one organic base, e.g. B. pyridine, quinoline or tiethylamine be used as a solvent for the esterification. The esterification can also be carried out in the absence of a solvent, e.g. B. by simply heating the components in the presence of sodium acetate. The Reaction temperature is between -50 ° and + 250 °, preferably between -20 ° and + 80 °. At these temperatures are the esterification reactions usually after 15 minutes ended up to 48 hours.

In particular, the reaction conditions depend on the Esterification largely depends on the nature of the used Starting materials. So is a free carboxylic acid a free alcohol or phenol usually in Presence of a strong acid, for example one  Mineral acid such as hydrochloric acid or sulfuric acid, implemented. A preferred mode of reaction is implementation an acid anhydride or in particular one Acid chloride with an alcohol, preferably in one basic milieu, with particular bases Alkali metal hydroxides such as sodium or potassium hydroxide, Alkali metal carbonates or bicarbonates such as Sodium carbonate, sodium hydrogen carbonate, potassium carbonate or potassium hydrogen carbonate, alkali metal acetates such as Sodium or potassium acetate, alkaline earth metal hydroxides such as Calcium hydroxide or organic bases such as triethylamine, Pyridine, lutidine, collidine or quinoline are important are. Another preferred embodiment of the Esterification is that the alcohol or Phenol first in the sodium or potassium alcoholate or -phenolate transferred, e.g. B. by treatment with ethanolic sodium or potassium hydroxide solution, this isolated and together with sodium bicarbonate or potassium carbonate with stirring in acetone or diethyl ether suspended and this suspension with a solution of Acid chloride or anhydride in diethyl ether, acetone or DMF added, expediently at temperatures between about -25 and + 20 °.

The phases according to the invention consist of 2 to 25, preferably 6 to 18 components, including at least a compound of formula I. The other ingredients are preferably selected from the nematic or nematogenic substances, especially the known ones Substances from the classes of azoxybenzenes, Benzylidenanilines, biphenyls, terphenyls, phenyl or Cyclohexylbenzoate, cyclohexane-carboxylic acid phenyl or -cyclohexyl esters, phenylcyclohexanes, cyclohexylbiphenyls, Cyclohexylnaphthalenes, 1,4-bis-cyclohexylbenzenes,  4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclohexylpyrimidines, Phenyl or cyclohexyl dioxanes, if appropriate halogenated stilbenes, benzylphenyl ether, tolanes and substituted cinnamic acids.

The most important as components of such Compounds in question of liquid-crystalline phases can be characterized by Formula III,

R ⁶ -AGER ⁷ (III)

where A and E are each carbocyclic or heterocyclic Ring system from the 1,4-disubstituted benzene and Cyclohexane rings, 4,4′-disubstituted biphenyl, Phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-dioxane rings, 2,6-disubstituted naphthalene, di- and tetrahydronaphthalene, Quinazoline and tetrahydroquinazoline educated group,

-CH = CH - N (O) = N- -CH = CY - CH = N (O) - -C = C - CH ₂ -CH ₂ - -CO-O - CH ₂ -O- - CO-S - CH ₂ -S- -CH = N - COO-Ph-COO-

or a CC single bond, Y halogen, preferably chlorine, or -CN, and R ⁶ and R ⁷ alkyl, alkoxy, alkanoyloxy or alkoxycarbonyloxy having up to 18, preferably up to 8 carbon atoms, or one of these radicals also CN, NC, NO ₂ , CF ₃ , F, Cl or Br mean.

In most of these compounds, R ⁶ and R ⁷ are different from one another, one of these radicals usually being an alkyl or alkoxy group. However, other variants of the proposed substituents are also common. Many such substances or mixtures thereof are commercially available. All substances are available according to methods known from the literature.

The phases according to the invention contain about 0.1 to 60, preferably 2 to 25%, one or more compounds of formula I.

The phases according to the invention are produced in yourself in the usual way. As a rule, the components dissolved in one another, expediently at elevated temperature.

By means of suitable additives, the liquid crystalline Phases according to the invention are modified so that they in all types of Liquid crystal display elements can be used.

Such additives are known to the expert and in the Literature described in detail. For example, you can Conductive salts, preferably ethyl-dimethyl-dodecyl-ammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylboranate or complex salts of crown ethers (cf. e.g. Haller et al., Mol. Cryst. Liq. Cryst. Volume 24, pages 249-258 [1973]) to improve conductivity, dichroic Dyes for the production of colored guest-host systems or substances for changing the dielectric anisotropy, the viscosity and / or the orientation of the nematic phases are added. Such substances are for example in DE-OS 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430, 28 53 728 and 29 02 177.  

The following examples are intended to illustrate the invention without limiting it. Percentages above and below mean percentages by weight; all temperatures are given in degrees Celsius. "Customary work-up" means: if necessary, water and / or an organic solvent such as toluene, CH ₂ Cl ₂ or CHCl _{3 are} added, the mixture is separated off, the organic phase is evaporated and the residue is purified by chromatography and / or crystallization.

Example 1

A mixture of 36 g of trans-1-p-bromophenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane, 10 g of Cu ₂ (CN) ₂ , 120 ml of pyridine and 60 ml of N-methylpyrrolidone is heated to 160 ° for 2 hours . The mixture is cooled, a solution of 120 g of FeCl ₃ .6H ₂ O in 600 ml of 20% hydrochloric acid is added, the mixture is heated to 70 ° with stirring for 1.5 hours, worked up as usual and gives trans-1-p-cyanophenyl 4- (trans-4-methoxymethylcyclohexyl) cyclohexane.

The following is obtained analogously from the corresponding bromine compounds:

trans-1-p-cyanophenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-cyanophenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-cyanophenyl-4- (trans-4-butoxymethylcyclohexyl) cyclohexane
trans-1-p-cyanophenyl-4- (trans-4- (3-butenyl) cyclohexyl) cyclohexane
trans-1-p-cyanophenyl-4- (trans-4- (3-pentenyl) cyclohexyl) cyclohexane
trans-1- (3-fluoro-4-cyanophenyl) -4- (trans-4-methoxymethylcyclohexy) cyclohexane
trans-1- (3-fluoro-4-cyanophenyl) -4- (trans-4-ethoxymethylcyclohexyl) cyclohexane

Example 2

A mixture of 30 g of trans-1-p-hydroxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane, 6.9 g of K ₂ CO ₃ , 25 g of hexyl iodide and 250 ml of DMF is heated to 80 ° with stirring for 16 hours , then cooled and worked up as usual. Trans-1-p-hexoxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane is obtained.

The following are produced analogously:

trans-1-p-methoxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-ethoxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-propoxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-butoxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-pentoxyphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane

Example 3

A solution of 1- (p-propylphenyl) -4- (trans-4-methoxymethylcyclohexyl) cyclohexanol {obtainable by reducing methyl trans-4- (4-oxocyclohexyl) cyclohexanecarboxylic acid) (J. Am. Chem. Soc. 73, 2388 [1950]) with LiAlH ₄ after prior protection of the carbonyl group, etherification with methyl iodide in THF in the presence of NaH, removal of the protective group and reaction with p-propylmagnesium bromide} in ethanol is hydrogenated in the presence of Raney nickel. Trans-1-p-propylphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane is obtained.

The following are produced analogously:

trans-1-p-butylphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-pentylphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-heptylphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-fluorophenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-methylphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane
trans-1-p-ethylphenyl-4- (trans-4-methoxymethylcyclohexyl) cyclohexane

trans-1-p-methylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-ethylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-propylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-butylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-pentylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-hexylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-heptylphenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-fluorophenyl-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane
trans-1-p-methylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-ethylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-propylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-butylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-pentylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-hexylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-heptylphenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane
trans-1-p-fluorophenyl-4- (trans-4-propoxymethylcyclohexyl) cyclohexane

Example 4

0.12 mol of methyl iodide (17.0 g) is added to a mixture of 0.1 mol of NaH (4.4 g of a 58% oil dispersion) in 60 ml of THF at 45 ° with the exclusion of atmospheric oxygen and moisture and then within one hour 27.4 g of trans-1-p-hydroxymethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane [obtainable by saponification of trans-1-p-cyanophenyl-4- (trans-4-pentylcyclohexyl) cyclohexane and Reduction of the acid with LiAlH ₄ ] in 50 ml THF. After 2 hours, the mixture is cooled, mixed with aqueous THF and worked up as usual. Trans-1-p-methoxymethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane is obtained

The following are produced analogously:

trans-1-p-methoxymethylphenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p-methoxymethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p-methoxymethylphenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p-methoxymethylphenyl-4- (trans-4-heptylcyclohexyl) cyclohexane

trans-1-p-ethoxymethylphenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p-ethoxymethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p-ethoxymethylphenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p-ethoxymethylphenyl-4- (trans-4-heptylcyclohexyl) cyclohexane
trans-1-p-ethoxymethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane

trans-1-p-propoxymethylphenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p-propoxymethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p-propoxymethylphenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p-propoxymethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane
trans-1-p-propoxymethylphenyl-4- (trans-4-hexylcyclohexyl) cyclohexane
trans-1-p-propoxymethylphenyl-4- (trans-4-heptylcyclohexyl) cyclohexane

trans-1-p-butoxymethylphenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p-butoxymethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p-butoxymethylphenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p-butoxymethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane
trans-1-p-butoxymethylphenyl-4- (trans-4-hexylcyclohexyl) cyclohexane
trans-1-p-butoxymethylphenyl-4- (trans-4-heptylcyclohexyl) cyclohexane

trans-1-p-methoxyethylphenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p-methoxyethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p-methoxyethylphenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p-methoxyethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane
trans-1-p-methoxyethylphenyl-4- (trans-4-hexylcyclohexyl) cyclohexane
trans-1-p-methoxyethylphenyl-4- (trans-4-heptylcyclohexyl) cyclohexane

trans-1-p-ethoxyethylphenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p-ethoxyethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p-ethoxyethylphenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p-ethoxyethylphenyl-4- (trans-4-pentylcyclohexyl) cyclohexane
trans-1-p-ethoxyethylphenyl-4- (trans-4-hexylcyclohexyl) cyclohexane
trans-1-p-ethoxyethylphenyl-4- (trans-4-heptylcyclohexyl) cyclohexane

trans-1-p- (3-butenyl) phenyl-4- (trans-4-ethylcyclohexyl) cyclohexane
trans-1-p- (3-butenyl) phenyl-4- (trans-4-propylcyclohexyl) cyclohexane
trans-1-p- (3-butenyl) phenyl-4- (trans-4-butylcyclohexyl) cyclohexane
trans-1-p- (3-butenyl) phenyl-4- (trans-4-pentylcyclohexyl) cyclohexane
trans-1-p- (3-butenyl) phenyl-4- (trans-4-hexylcyclohexyl) cyclohexane
trans-1-p- (3-butenyl) phenyl-4- (trans-4-heptylcyclohexyl) cyclohexane

Example 5

A mixture of 0.2 moles of trans-4- (trans-4-methoxymethylcyclohexyl) - cyclohexane carboxylic acid chloride, 1 mole of p-fluorophenol and 100 ml of pyridine is stirred for 12 hours. Then 800 ml of toluene are added and the toluene layer is washed in succession with hydrochloric acid, sodium hydroxide solution and Water. After drying, it is worked up as usual. This gives trans-4- (trans-4-methoxymethylcyclohexyl) - p-fluorophenyl cyclohexanecarboxylate.

The following are produced analogously:

3,4-difluorophenyl trans-4- (trans-4-methoxymethylcyclohexyl) cyclohexane carboxylic acid
trans-4- (trans-4-methoxymethylcyclohexyl) cyclohexane carboxylic acid 2,4-difluorophenyl ester

trans-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane carboxylic acid p-fluorophenyl ester
3,4-difluorophenyl trans-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane carboxylic acid
trans-4- (trans-4-ethoxymethylcyclohexyl) cyclohexane carboxylic acid 2,4-difluorophenyl ester

trans-4- (trans-4-propoxymethylcyclohexyl) cyclohexane carboxylic acid p-fluorophenyl ester
3,4-difluorophenyl trans-4- (trans-4-propoxymethylcyclohexyl) cyclohexane carboxylic acid
trans-4- (trans-4-propoxymethylcyclohexyl) cyclohexane carboxylic acid 2,4-difluorophenyl ester

trans-4- (trans-4-methoxyethylcyclohexyl) cyclohexane carboxylic acid p-fluorophenyl ester
3,4-difluorophenyl trans-4- (trans-4-methoxyethylcyclohexyl) cyclohexane carboxylic acid
trans-4- (trans-4-methoxyethylcyclohexyl) cyclohexane carboxylic acid 2,4-difluorophenyl ester

The following are examples of dielectrics according to the invention containing at least one compound of the formula I:  

Example A

A liquid crystalline phase consisting of

20% p-trans-4-propylcyclohexylbenzonitrile, 15% p-trans-4-pentylcyclohexylbenzonitrile, 20% trans-1-p-ethylphenyl-4-propylcyclohexane, 20% trans-1-p-methoxyphenyl-4-propylcyclohexane, 5% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl, 5% 4,4'-bis (trans-4-propylcyclohexyl) -2-fluorobiphenyl, 5% 4,4'-bis (trans-4-pentylcyclohexyl) -2-flourbiphenyl, 5% 4- (trans-4-pentylcyclohexyl) -4 ′ - (trans-4- propyl-cyclohexyl) biphenyl and 5% 4- (trans-4-pentylcyclohexyl-4 ′ - (trans-4- propylcyclohexyl) -2-fluorobiphenyl

has a clearing point of 62 ° and a viscosity of 14.6 mm ² / s at 20 °. An addition of 20% trans-1-p-methoxymethylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane maintains the clearing point at 77 °, while the viscosity is only slightly increased at 14.9 mm ² / s.

Example B

A liquid crystalline phase consisting of

5% 3-fluoro-4-cyanophenyl p-ethylbenzoate, 5% 3-fluoro-4-cyanophenyl p-propylbenzoate, 10% 3-fluoro-4-cyanophenyl p-pentylbenzoate, 10% p-heptylbenzoic acid-3-flour-4-cyanophenyl ester, 30% trans-1-p-propylphenyl-4-pentylcyclohexane 20% trans-1-p-ethoxyphenyl-4-propylcyclohexane, 5% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl, 5% 4,4'-bis (trans-4-pentylcyclohexyl) biphenyl,  5% 4- (trans-4-pentylcyclohexyl) -4 ′ - (trans-4- propylcyclohexyl) biphenyl and 5% 4- (trans-4-pentylcyclohexyl) -4 ′ - (trans-4- propylcyclohexyl) -2-fluorobiphenyl

has a clearing point of 58 ° and a viscosity of 19.5 mm ² / s at 20 °. The addition of 20% trans-1-p-2-butenylphenyl-4- (trans-4-propylcyclohexyl) cyclohexane increases the clearing point to 75 °, the viscosity being simultaneously reduced by 18.7 mm ² / s.

Claims (5)

1. hydroterphenyls of the formula I R ¹ -Cy-Cy-Z-Ph-R ² (I) where R ^{1 is} alkyl, R ² H, F, Cl, Br, J, OH, CN, NCS, alkyl, -O-alkyl, -COOR ³ or -O-CO-R ³ , Z-COO- or a single bond, R ³ H, alkyl, -Cy-alkyl, -Ph-alkyl, Ph-O-alkyl, -Ph-CN or -Ph- F, Cy1,4-cyclohexylene, Ph1,4-phenylene or 1,4-phenylene substituted in the 2- or 3-position by fluorine, and alkyl denotes an alkyl group with 1-10 C atoms, in which also one or more non-adjacent and CH ₂ groups not linked to -O- or Ph can be replaced by -O- and / or -CH = CH-, with the proviso that in at least one alkyl group in R ¹ and / or R ² at least one CH ₂ - Group is replaced by -O- or -CH = CH-. 2. A process for the preparation of hydroterphenylene of the formula I according to claim 1, characterized in that a compound corresponding to the formula I, which, however, contains (instead of) hydrogen atoms (a) reducible group (s) and / or additional CC bond, with a reducing agent treated and that, if appropriate the radical R ² into another radical R ² is converted in a compound of formula I. 3. Use of the compound of formula I after Claim 1 as components of liquid crystalline Phases for electro-optical display elements. 4. Liquid crystalline phase for electro-optical display elements with at least two liquid crystalline Components, characterized in that at least a component is a compound of formula I. Claim 1 is. 5. Electro-optical display element, characterized in that it contains a phase according to claim 4.