DE3711510A1 - New liquid crystal mustard oil cpds. - prepn. and use in lcd, esp. as dielectric in electro-optical display, with low viscosity and mol. association - Google Patents

Abstract

New mustard oils are of formula (I) R-(A1-Z1)n-A2-Z2-A3-(CH2)p-NCS (I); R = H or 1-15C alkyl, in which one or 2 non-adjacent CH2 gps. can be replaced by -O-, -CC-, -CH=CH-, -CO-, -O-CO- and/or -CO-O-; A1 and A2 independently = 1,4-cyclohexylene (opt. with one or more substits. and opt. with one or 2 non-adjacent CH2 gps. replaced by -O-and/or -S-), piperidin-1,4-diyl; 1,4-bicyclo(2,2,2)octylene; or 1,4-phenylene (opt. with one or 2 F, Cl,Me, N3, NCS and/or CN substits. andopt. with one or 2 CH gps. replaced by N); A3 = 1,4-cyclohexylene (opt. with one or more substits.); or 1,4-phenylene (opt. with one or 2 F, Cl,Me, N3, NCS, CF3 and/or CN substits.); Z1 and Z2 = -CO-O-, -CH2CH2-, -CHCN-CH2-, -CH2-CHCN-, -CH=CH-, -CC-, -OCH2-, -CH2O-, -CH=N-, -N=CH-, -NO=N-, -N=NO- or a single bond; n = 0, 1 or 2; p = 1, 2, 3, 4, 5 or 6. The prepn. of (I) is claimed. USE/ADVANTAGE - (I) are claimed for use in liquid crystal (LC) phases contg. at least 2 LC components and these are claimed for use in LCDs and as dielectric electroptical display cells. They are useful for displays operating on the twisted cell, guest-host effect, aligned phase deformation effect or dynamic scattering effect. (I) are stable LC or mesogenic cpds. with relatively low viscosity and little or no tendency to form mol. associates. they form stable LC phases with wide mesophase region and advantageous optical and dielectric anisotropy.

Description

The invention relates to mustard oils of the formula I

R- (A¹-Z¹) _n -A²-Z²-A³- (CH₂) _p -NCS (I)

wherein
RH or alkyl with 1-15 C atoms, wherein also one or two non-adjacent CH₂ groups by -O-, -C≡C-, -CH≡CH-, -CO-, -O-CO- and / or -CO-O- can be replaced, A¹ and A² each represent an unsubstituted or mono- or polysubstituted 1,4-cyclohexylene group, in which one or two non-adjacent CH₂ groups can also be replaced by -O- and / or -S-, a piperidine-1,4-diyl or 1,4-bicyclo [2,2,2] octylene group or an unsubstituted or by one or two F and / or Cl atoms and / or CH₃ groups and / or N₃- Groups and / or NCS groups and / or CN groups substituted 1,4-phenylene group, in which one or two CH groups can also be replaced by N, A³ an unsubstituted or mono- or polysubstituted 1,4-cyclohexylene group or an unsubstituted one or 1,4-phenylene group substituted by one or two F and / or Cl atoms and / or CH₃ groups and / or N₃ groups and / or NCS groups and / or CF₃ groups and / or CN groups, Z 1 and Z 2 each -CO-O -, -O-CO-, -CH₂CH₂-, -CHCN-CH₂-, -CH₂-CHCN-, -CH = CH-, -C≡C-, -OCH₂-, -CH₂O-, -CH = N-, -N = CH-, -NO = N-, -N = NO- or a single bond, n is 0, 1 or 2 and p is 1, 2, 3, 4, 5 or 6.

For the sake of simplicity, Cy hereinafter means one 1,4-cyclohexylene group, Bi a bicyclo [2,2,2] octylene 1,4-diyl group, Pip a piperidine-1,4-diyl group, Phe a 1,4-phenylene group, Pym a pyrimidine-2,5-diyl group, Pyr is a pyridine-2,5-diyl group and Pyz is a Pyrazine-2,5-diyl group, where Cy and / or Phe and / or Pyr and / or Pyz unsubstituted or by one or two F and / or Cl atoms and / or CH₃ groups and / or N₃ groups and / or NCS groups and / or CF₃ groups and / or CN groups can be substituted. The 1,4-Cyclohexylene groups are preferably trans-1,4-cyclohexylene.

The compounds of formula I can be used as components liquid crystalline phases are used, in particular for displays based on the principle of twisted Cell, the guest-host effect, the effect of the deformation erected phase or the effect of dynamic Scatter.  

The invention was based, new stable task find liquid-crystalline or mesogenic compounds, the as components of liquid crystalline phases are suitable and in particular a comparative one have low viscosity and a reduced viscosity Show tendency to form associates.

Liquid-crystalline mustard oils are known from EP-O 1 26 883, which contain a trans-cyclohexylphenyl group. It has now been found that compounds of the formula I as Components of liquid crystalline phases are particularly suitable are. In particular, they have comparative low viscosities and have no or only a low one Tendency to form molecular associations. With They can be used to make stable liquid-crystalline phases with a wide mesophase range and advantageous values obtained for the optical and dielectric anisotropy.

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

The compounds of formula I have a wide range Scope of application. Depending on the selection of the Substituents can use these compounds as base materials serve from which liquid crystalline phases for the majority are composed; but it can also compounds of the formula I liquid-crystalline base materials added from other classes of compounds be, for example, the dielectric and / or optical anisotropy of such a dielectric influence and / or around its threshold voltage and / or to lower its viscosity.  

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 conveniently located temperature range. Are chemical, thermal and against light they stable.

The invention thus relates to the compounds of the formula I and a process for the preparation of the compounds of the formula I according to claim 1, characterized in that a corresponding amine is treated with thiophosgene, or that a corresponding amine is converted into a dithiocarbamate with carbon disulfide and the latter treated with hydrogen peroxide or a chlorocarbonic acid ester, or by reacting a corresponding halide of the formula I with a salt of thiocyanic acid,
or treating a compound which otherwise corresponds to the formula I but contains one or more reducible groups and / or CC bonds instead of H atoms with a reducing agent,
or that for the preparation of esters of the formula I (in which Z 1 and / or Z 2 are -CO-O- or -O-CO- and / or R contains a carboxyl group) a corresponding carboxylic acid or one of its reactive derivatives with a corresponding alcohol or one of its reactive derivatives,
or that a corresponding hydroxy compound is etherified to prepare ethers of the formula I (in which R is an alkoxy group and / or Z 1 and / or Z 2 is an -OCH₂- or -CH₂O group).

The invention furthermore relates to the use of Compounds of formula I as components of liquid crystalline Phases. The invention also relates to liquid crystalline Phases containing at least one Compound of formula I and liquid crystal display elements, in particular electro-optical display elements that contain such phases.

The compounds of formula I accordingly include Connections with two rings of sub-formula I a:

R-A²-Z²-A³- (CH₂) _p -NCS (I a)

Compounds with three rings of sub-formulas I b and I c:

R-A¹-A²-Z²-A³- (CH₂) _p -NCS (I b)
R-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I c)

as well as compounds with four rings of sub-formulas I d to I g:

R-A¹-A¹-A²-Z²-A³- (CH₂) _p -NCS (I d)
R-A¹-Z¹-A¹-A²-Z²-A³- (CH₂) _p -NCS (I e)
R-A¹-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I f)
R-A¹-Z¹-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I g)

as well as compounds with five rings of the sub-formulas I h to I o:

R-A¹-A¹-A¹-A²-Z²-A³- (CH₂) _p -NCS (I h)
R-A¹-Z¹-A¹-A¹-A²-Z²-A³- (CH₂) _p -NCS (I i)
R-A¹-A¹-Z¹-A¹-A²-Z²-A³- (CH₂) _p -NCS (I j)
R-A¹-A¹-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I k)
R-A¹-Z¹-A¹-Z¹-A¹-A²-Z²-A³- (CH₂) _p -NCS (I l)
R-A¹-Z¹-A¹-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I m)
R-A¹-A¹-Z¹-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I n)
R-A¹-Z¹-A¹-Z¹-A¹-Z¹-A²-Z²-A³- (CH₂) _p -NCS (I d)

In the compounds of the formulas above and below R is preferably alkyl, furthermore alkoxy.

A¹, A² and A³ are preferably Cy, Phe, Pym or Pyr; in particular preferably Cy or Phe; the compounds preferably contain of formula I no more than one of the radicals Bi, Pyd, Pym, Pyr or Pyz.

A³ is preferably Cy. p is preferably 2. n is preferably 0 or 1, particularly preferably 0. R is preferably alkyl or alkoxy.

Z¹ and Z² are preferably single bonds, in the second Line preferably -CO-O-, -O-CO- or -CH₂CH₂ groups.

If R is an alkyl radical and / or an alkoxy radical, it can be straight or branched. Preferably  if it is straight-chain, it has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly preferably means ethyl, propyl, butyl, pentyl, Hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or Heptoxy, also methyl, octyl, nonyl, decyl, undecyl, dodecyl, Tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, Decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

Oxaalkyl preferably means straight-chain 2-oxapropyl (= Methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R is an alkyl radical in which a CH₂ group is replaced by -CH≡CH-, it can be straight-chain or be branched. It is preferably straight-chain and has 2 to 10 carbon atoms. It therefore means special Vinyl, prop-1, or prop-2-enyl, but-1-, 2- or but-3- enyl, pent-1-, 2-, 3- or pent-4-enyl, hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- or hept- 6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, Non-1-, 2-, 3-, 4-, 5-, 6-, 7- or Non-8-enyl, Dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or Dec-9-enyl.

Compounds of the formula I with branched wing groups R can occasionally due to better solubility in the usual liquid-crystalline base materials of importance be, but especially as chiral dopants if they are optically active. Smectic compounds of this type are suitable itself as components for ferroelectric materials.

Branched groups of this type usually do not contain more than a chain branch. Preferred branched R radicals are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl, 2-methylpentyl, 3-methylpentyl,  2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 1-methylheptoxy.

Formula I includes both the racemates of these compounds as well as the optical antipodes and their mixtures. Among the compounds of formula I and I a to I o those in which at least one of the residues contained therein one of the preferred specified Has meanings.

Particularly preferred smaller groups of compounds are those of the formula I 1 to I 14, in which Phe 1,4- Phenylene, Cy 1,4-Cyclohexylene and PheF in 2- or 3-position 1,4-phenylene substituted by fluorine means:

R-Cy-Cy- (CH₂) _p -NCS (I 1)
R-Pym-Phe- (CH₂) _p -NCS (I 2)
R-Pym-PheF- (CH₂) _p -NCS (I 3)
R-Cy-COO-PheF- (CH₂) _p -NCS (I 4)
R-Cy-Phe-Cy- (CH₂) _p -NCS (I 5)
R-Cy-Pym-Phe- (CH₂) _p -NCS (I 6)
R-Cy-CH₂CH₂-Phe- (CH₂) _p -NCS (I 7)
R - Pym-CH₂CH₂-Phe- (CH₂) _p -NCS (I 8)
R-Cy-CH₂CH₂-Cy-Phe- (CH₂) _p -NCS (I 9)
R-Cy-CH₂CH₂-Cy-COO-Phe- (CH₂) _p -NCS (I 10)
R-Cy-Phe-Phe- (CH₂) _p -NCS (I 11)
R-Cy-PheF-Phe- (CH₂) _p -NCS (I 12)
R-Cy-Phe-Phe-Cy- (CH₂) _p -NCS (I 13)
R-Cy-PheF-Phe-Cy- (CH₂) _p -NCS (I 14)

In the compounds of formula I are those stereoisomers preferred, in which the rings Cy, Pip trans-1,4- are disubstituted. Those of the above Formulas that contain one or more groups Pip, Pyd, Pym, Pyr and / or contain Pyz, each enclose the two 2,5- (Pym, Pyr) or 1,4-position isomers (Pip).

In the compounds of formula I in which A¹ is for one in the 2-position substituted by R ring Pyd, Pym, Pyr or Pyz, R is preferably alkyl.

Compounds of the formula I in which R each straight-chain or at most single-branched Alkyl groups or alkoxy groups with 1-12, in particular 2-10 C atoms means.

The following smaller groups are particularly preferred of compounds in which Pym pyrimidine-2,5-diyl, Phe 1,4-phenylene, Cy 1,4-cyclohexylene and PheF in 2- or 3-position is substituted by fluorine-substituted 1,4-phenylene.

Alkyl preferably means straight-chain methyl, ethyl, Propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or Decyl; Oxaalkyl preferably means straight-chain 2-oxapropyl (= methoxymethyl), 2- (= ethoxymethyl) or  3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxa heptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

I. alkyl-Cy-Cy- (CH₂) _p -NCS
Oxaalkyl-Cy-Cy- (CH₂) _p -NCS II. Alkyl-Pym-Phe- (CH₂) _p -NCS
Alkoxycarbonyl-Pym-Phe- (CH₂) _p -NCS
Alkyl-Pym-Phe-2F, (CH₂) _p -NCS
Alkyl-Pym-Phe-3F, (CH₂) _p -NCS
Alkoxycarbonyl-Pym-Phe-2F, - (CH₂) _p -NCS
Alkoxycarbonyl-Pym-Phe-3F, (CH₂) _p -NCS III. Alkyl-Cy-COO-Phe-2F, (CH₂) _p -NCS
Alkyl-Cy-COO-Phe-3F, (CH₂) _p -NCS IV: Alkyl-Cy-Phe-Cy- (CH₂) _p -NCS V. Alkyl-Cy-Pym-Phe- (CH₂) _p -NCS
Alkoxycarbonyl-Cy-Pym-Phe- (CH₂) _p -NCS VI.Alkyl-Pym-CH₂CH₂-Phe- (CH₂) _p -NCS
Oxaalkyl-Pym-CH₂CH₂-Phe- (CH₂) _p -NCS VII. Alkyl-Cy-CH₂CH₂-Phe- (CH₂) _p -NCS
Alkoxycarbonyl-Cy-CH₂CH₂-Phe- (CH₂) _p -NCS VIII.Alkyl-Cy-CH₂CH₂-Cy-Phe- (CH₂) _p -NCS
Alkoxycarbonyl-Cy-CH₂CH₂-Cy-Phe- (CH₂) _p -NCS
Alkyl-Cy-CH₂CH₂-Cy-Phe-2F, (CH₂) _p -NCS
Alkyl-Cy-CH₂CH₂-Cy-Phe-3F, (CH₂) _p -NCS
Alkoxycarbonyl-Cy-CH₂CH₂-Cy-Phe-2F, (CH₂) _p -NCS
Alkoxycarbonyl-Cy-CH₂CH₂-Cy-Phe-3F, (CH₂) _p -NCS IX.Alkyl-Cy-CH₂CH₂-Cy-COO-Phe- (CH₂) _p -NCS X: alkyl-Cy-Phe-Phe- (CH₂ ) _p -NCS
Oxaalkyl-Cy-Phe-Phe- (CH₂) _p -NCS
Alkyl-Cy- (Phe-2F) -Phe- (CH₂) _p -NCS
Alkyl-Cy- (Phe-3F) -Phe- (CH₂) _p -NCS XI.Alkyl-Cy-Phe-Phe-Cy- (CH₂) _p -NCS
Alkyl-Cy- (Phe-2F) -Cy- (CH₂) _p -NCS
Alkyl-Cy- (Phe-3F) -Cy- (CH₂) _p -NCS

The compounds of formula I are known per se Methods as described in the literature (e.g. in standard works such as Houben-Weyl Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart Bd IX, P. 867 ff.) Are described, namely under reaction conditions, known for the above-mentioned implementations and are suitable. You can also use known, Variants not mentioned here do.

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 connections Formula I implemented.

Preferred starting compounds are amines and halogen Compounds corresponding to formula I.

The compounds of the formula I can be prepared by using a compound that is otherwise of the formula I corresponds, but instead of H atoms one or more contains reducible groups and / or C-C bonds, reduced.  

Carbonyl groups are preferably used as reducible groups into consideration, especially keto groups, further e.g. B. free or esterified hydroxyl groups or aromatic bonded halogen atoms. Preferred starting materials for the Reduction correspond to Formula I, but can be in place a cyclohexane ring is a cyclohexene ring or cyclohexanone ring and / or instead of a -CH₂CH₂ group -CH≡CH group and / or instead of a -CH₂ group -CO group and / or a free one instead of an H atom or a functional one (e.g. in the form of its p-toluenesulfonate) modified OH group included.

The reduction can e.g. B. done by catalytic Hydrogenation at temperatures between about 0 ° and about 200 ° and pressures between about 1 and 200 bar in one inert solvents, e.g. B. an alcohol such as methanol, Ethanol or isopropanol, an ether such as tetrahydrofuran (THF) or dioxane, an ester such as ethyl acetate, one Carboxylic acid such as acetic acid or a hydrocarbon like cyclohexane. Suitable catalysts are useful Precious metals such as Pt or Pd, which are in the form of oxides (e.g. PtO₂, PdO), on a support (e.g. Pd on carbon, calcium carbonate or strontium carbonate) or in finely divided Form can be used.

Ketones can also be prepared using Clemmensen's methods (with Zinc, amalgamated zinc or tin and hydrochloric acid, useful in aqueous-alcoholic solution or in heterogeneous Phase with water / toluene at temperatures between about 80 and 120 °) or Wolff-Kishner (with hydrazine, useful in the 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 °) to the corresponding compounds of formula I, which contain alkyl groups and / or -CH₂CH₂ bridges, be reduced.  

Reductions with complex hydrides are also possible. For example, arylsulfonyloxy groups with LiAlH₄ be removed reductively, especially p-toluenesulfonyloxymethyl groups be reduced to methyl groups, appropriately in an inert solvent such as diethyl ether or THF at temperatures between about 0 and 100 °. Double bonds can with NaBH₄ or tributyltin hydride in Methanol are hydrogenated.

Esters of the formula I can also be correspondingly esterified Carboxylic acids (or their reactive derivatives) with alcohols or phenols (or their reactive Derivatives) can be obtained.

The corresponding carboxylic acids and alcohols or phenols are known or can be used in analogy to known methods getting produced.

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

As reactive derivatives of the alcohols mentioned or Phenols come in particular the corresponding metal alcoholates or phenolates, preferably an alkali metal such as sodium or potassium.

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 an organic Base, e.g. B. pyridine, quinoline or triethylamine 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 usually between -50 ° and + 250 °, preferably between -20 ° and + 80 °. At the esterification reactions are in these temperatures usually ended after 15 minutes to 48 hours.

The reaction conditions for the esterification depend in particular largely on the nature of the raw materials used from. So a free carboxylic acid with one free alcohol or phenol usually in the presence a strong acid, for example a mineral acid such as hydrochloric acid or sulfuric acid. A preferred one The reaction is the reaction of an acid anhydride or in particular an acid chloride with a Alcohol, preferably in a basic environment, where as bases in particular alkali metal hydroxides such as sodium or potassium hydroxide, alkali metal carbonates or bicarbonates like sodium carbonate, sodium hydrogen carbonate, Potassium carbonate or potassium hydrogen carbonate, alkali metal acetates such as sodium or potassium acetate, alkaline earth metal hydroxides like calcium hydroxide or organic bases like Triethylamine, pyridine, lutidine, collidine or quinoline are important. Another preferred embodiment the esterification is that you have the alcohol or the 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 suspended in acetone or diethyl ether with stirring and this suspension with a solution of the acid chloride or anhydrides in diethyl ether, acetone or DMF offset, expedient at temperatures between about -25 ° and + 20 °.

Ethers of formula I (wherein R represents an alkoxy group and / or wherein Z¹ and / or Z² is a -OCH₂- or a -CH₂O group) are corresponding by etherification Hydroxy compounds, preferably corresponding phenols, available, the hydroxy compound expediently first in a corresponding metal derivative, e.g. B. by Treat with NaH, NaNH₂, NaOH, KOH, Na₂CO₃ or K₂CO₃ into the corresponding alkali metal alcoholate or alkali metal phenolate is transferred. This can then be done with the corresponding alkyl halide, sulfonate or dialkyl sulfate be implemented, suitably in an inert Solvents such as acetone, 1,2-dimethoxyethane, DMF or Dimethyl sulfoxide or an excess of aqueous or aqueous-alcoholic NaOH or KOH at temperatures between about 20 ° and 100 °.

Compounds of the formula I are particularly advantageous by reacting appropriate amines with thiophosgene received, a procedure that in itself in the German Patent specification 11 17 257 is described.

Such amines can be prepared by methods known per se be preserved.

You can, for example, by reductive splitting of the corresponding azides can be obtained as in the DE-OS 37 04 340 is described. Suitable reducing agents  for this are e.g. B. using hydrogen transition metal catalysts such as platinum or Palladium, especially palladium / animal charcoal.

Such amines can also be obtained by reducing the corresponding nitriles, the representation of which, for. Tie DE-OS 27 02 598, 26 36 684 and 31 51 367 are described with various reducing agents such as alanates and boranates, preferably lithium aluminum hydride, or by hydrogenation using transition metal catalysts, preferably Raney nickel.

Halogen compounds, such as Chlorides, bromides and iodides, which in turn come from the corresponding hydroxy compounds are accessible, with ammonia or an ammonia equivalent such as. B. Phthalimide potassium under metal salt catalysis, in particular with the addition of copper and / or its salts be converted to amines.

Such hydroxy compound can e.g. B. by reducing the corresponding carboxylic acid esters with alanates or boranates, preferably lithium aluminum hydride obtained will.

Organometallic compounds which contain (p -1) methylene groups can also be reacted with aldehydes, preferably with formaldehyde, or those which contain (p -2) methylene groups with epoxides, preferably ethylene oxide, to give the corresponding hydroxy compounds.

These can be reacted with reactive sulfonic acid halides Presence of a base, preferably a tertiary Amines such as B. triethylamine, pyridine or lutidine  the corresponding sulfonic acid esters, for example Tosylates, brosylates, nosylates, mesylates, triflates, Nonaflaten or Tresylaten, are implemented.

The reactants are without solvent or expediently in the presence of an inert solvent brought together to react.

Suitable diluents are preferably ethers such as Diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, Amides such as dimethylformamide, hexamethylphosphoric triamide, Hydrocarbons such as hexane, cyclohexane, benzene, Toluene, xylene, halogenated hydrocarbons such as dichloromethane, Chloroform, carbon tetrachloride, tetrachlorethylene, Sulfoxides such as dimethyl sulfoxide, sulfolane, alcohols such as methanol, ethanol, isopropanol and other organic Solvents such as acetonitrile and nitromethane. Also Water or mixtures of these solvents with one another and / or with water are for the above implementation suitable. The reaction temperatures are between -20 and + 100 °, preferably between 0 and 50 °. With these Temperatures are usually the conversions after 30 Minutes to 24 hours finished.

In a further advantageous method, corresponding Oxy compound or the halides accessible from them reacted with a salt of thiocyanic acid. Suitable Salts for this are, for example, ammonium, sodium and Potassium rhodanide. The implementation is advantageous in the presence an inert non-polar solvent. Good hydrocarbons such as hexane are particularly suitable, Petroleum ether, ligroin, cyclohexane, benzene, toluene and Xylene. The reaction temperatures are between 0 and 150 °, preferably between 20 and 100 °. At these temperatures the implementations are usually after 1 to 60 hours ended.  

Finally, amines can be used instead of the NCS group have an amino group with carbon disulfide in one Dithiocarbamat be transferred and this further under the Influence of various reagents on those according to the invention Mustard oils of formula I are implemented. For execution suitable reagents for this reaction sequence are, for example Hydrogen peroxide (see DE 21 05 473), cyanogen chloride (DE 26 03 508), cyanuric chloride (DE 19 35 302), chlorocarbonic acid ester (DE 11 78 423), alkali hypochlorite or alkali chlorite (DE 9 52 083), phosgene (DE 10 68 250) and heavy metal salts (Dains et al., Org. Synth. Coll. Vol. 1 (1964) 447).

The preparation of the dithiocarbamates from those of the formula I. corresponding amino compounds and carbon disulfide expediently takes place in an inert solvent in the presence of an amine. Suitable solvents are for example hydrocarbons such as hexane, petroleum ether, Ligroin, cyclohexane, benzene, toluene and xylene. As an amine are preferably tertiary amines such as Pyridine, triethylamine or ethyldiisopropylamine are used. The ammonium dithiocarbamates obtained can by e.g. B. centrifugation or filtration, the However, they can also be used in situ to produce mustard oils of the formula I be implemented.

The reaction temperatures for the preparation of the dithiocarbamates are between -20 and + 100 °, preferably between 0 and 40 °. At these temperatures they are Reactions usually complete after 1 to 24 hours.

To convert the ammonium dithiocarbamates is preferred with chlorinated carbonic acid esters or hydrogen peroxide implemented.  

The ammonium dithiocarbamates isolated or obtained in situ can be conveniently in the presence a suitable solvent such as ether such as diethyl ether, tetrahydrofuran, dioxane and halogenated hydrocarbons like dichloromethane, chloroform, Carbon tetrachloride, 1,2-dichloroethane in the case of Chlorocarbonic acid ester or water, formic acid, acetic acid in the case of hydrogen peroxide for reaction bring. At reaction temperatures from -20 to 100 °, the reactions are preferably between 0 and 80 ° usually finished after 1 to 24 hours.

Particularly suitable for the production of mustard oils Formula I is the reaction of suitable amines with carbon disulfide and triethylamine to triethylammonium dithiocarbamates and converting them into mustard oils by treatment with chlorinated carbonate or hydrogen peroxide.

A base of formula I can with an acid in the associated Acid addition salt can be transferred. For this Implementation, inorganic acids can be used e.g. B. sulfuric acid, nitric acid, hydrohalic acids such as hydrochloric acid or hydrobromic acid, Phosphoric acids such as orthophosphoric acid, sulfamic acid, also organic acids, especially aliphatic, alicyclic, araliphatic, aromatic or heterocyclic mono- or polybasic carbon, sulfone or sulfuric acids, e.g. B. formic acid, acetic acid, Propionic acid, pivalic acid, diethyl acetic acid, malonic acid, Succinic acid, pimelic acid, fumaric acid, maleic acid, Lactic acid, tartaric acid, malic acid, benzoic acid, Salicylic acid, 2- or 3-phenylpropionic acid, citric acid, Gluconic acid, ascorbic acid, nicotinic acid, isonicotinic acid, Methane or ethanesulfonic acid, ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalene mono- and disulfonic acids, lauryl sulfuric acid.  

Conversely, it is possible to use an acid addition salt a compound of formula I, the base of formula I. by treatment with a base, e.g. B. with a strong inorganic base such as KOH or NaOH.

The liquid-crystalline phases according to the invention consist from 2 to 25, preferably 3 to 15 components, including at least one compound of formula I. The others Components are preferably selected from the nematic or nematogenic substances, especially the known substances from the classes of azoxybenzenes, Benzylidenanilines, biphenyls, terphenyls, phenyl or Cyclohexylbenzoate, cyclohexane-carboxylic acid phenyl or -cyclohexyl esters, phenylcyclohexanes, cyclohexylbiphenyls, Cyclohexylcyclohexanes, cyclohexylnaphthalenes, 1,4-bis cyclohexylbenzenes, 4,4'-biscyclohexylbiphenyls, phenyl or cyclohexylpyrimidines, phenyl- or cyclohexyldioxanes, Phenyl- or cyclohexyldithanes, 1,2-bis-phenylethanes, 1,2-biscyclohexylethane, 1-phenyl-2-cyclohexylethane, optionally halogenated stilbenes, benzylphenyl ether, Tolanes and substituted cinnamic acids.

The most important as components of such liquid crystalline Leave phases in question are characterized by Formula II,

R¹-L-G-E-R² (II)

where L and E each have a carbo- or heterocyclic ring system consisting of the system consisting of 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,
G
-CH = CH - N (O) = N- -CH = CY - CH = N (O) - -C≡C - CH₂-CH₂- -CO-O - CH₂-O- -CO-S --CH₂-S- -CH = N - COO-Phe-COO-

or a C-C single bond, Y halogen, preferably Chlorine, or -CN, and R¹ and R² alkyl, alkoxy, alkanoyloxy or alkoxycarbonyloxy with up to 18, preferably up to 8 carbon atoms, or one of these residues also CN, NO₂, CF₃, F, Cl or Br mean.

Most of these compounds are R1 and R2 from each other different, one of these residues usually one Is alkyl or alkoxy group. But also other variants the proposed substituents are common. Lots such substances or mixtures thereof are commercially available available. All of these substances are known from the literature Methods can be produced.

The liquid-crystalline phases according to the invention contain about 0.1 to 99, preferably 10 to 95%, one or several compounds of formula I. Also preferred are liquid crystalline phases that are 0.1-50, in particular 0.5-30% of one or more compounds of the Formula I included. Also isotropic compounds of the formula I can be used in the phases according to the invention will.

The preparation of the liquid-crystalline according to the invention Phases take place in the usual way. Usually the components are dissolved into 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 that have become known 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-hexylbenzoate, tetrabutylammonium tetraphenylboranate or complex salts of crown ethers (cf. e.g. I. 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 z. B. 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 described.

The following examples are intended to illustrate the invention, without limiting it. Above and below mean Percentage percentages by weight. All temperatures are given in degrees Celsius.

In the following, "usual" processing means: if necessary Add water, extract with ether, methylene chloride or toluene and / or separating the organic Phase, drying, evaporation and purification by distillation under reduced pressure and / or crystallization and / or chromatography.

F. = melting point, K. = clearing point.

example 1

To a mixture of 8.2 g of 1,1-thiocarbonyldiimidazole and 100 ml of methylene chloride becomes a mixture of 6.6 g trans-4- (trans-4-propylcyclohexyl) cyclohexylmethylamine and 50 ml of methylene chloride. The reaction mixture is stirred for 16 hours at room temperature and at 0 ° C mixed with 70 ml of hydrochloric acid (1 normal). You get after usual work-up trans-4- (trans-4-propylcyclohexyl) - cyclohexylmethyl isothiocyanate with F. = 37 ° C, K. (extr.) = -50 ° C.

The following are produced analogously:
trans-4- (trans-4-ethylcyclohexyl) cyclohexylmethyl isothiocyanate
trans-4- (trans-4-butylcyclohexyl) cyclohexylmethyl isothiocyanate
trans-4- (trans-4-pentylcyclohexyl) cyclohexylmethyl isothiocyanate with F. = 24 ° C, K = 19 ° C
trans-4- (trans-4-hexylcyclohexyl) cyclohexylmethyl isothiocyanate
trans-4- (trans-4-heptylcyclohexyl) cyclohexylmethyl isothiocyanate
trans-4- (trans-4-octylcyclohexyl) cyclohexylmethyl isothiocyanate
2-trans-4- (trans-4-ethylcyclohexyl) cyclohexyl) ethyl 1-isothiocyanate
2-trans-4- (trans-4-propylcyclohexyl) cyclohexyl) ethyl-1-isothiocyanate with F. = 32 ° C, K. = 28 ° C
2-trans-4- (trans-4-butylcyclohexyl) cyclohexyl) ethyl 1-isothiocyanate
2-trans-4- (trans-4-pentylcyclohexyl) cyclohexyl) ethyl 1-isothiocyanate with F. = 23 ° C, K. = 40 ° C
2-trans-4- (trans-4-hexylcyclohexyl) cyclohexyl) ethyl 1-isothiocyanate
2-trans-4- (trans-4-heptylcyclohexyl) cyclohexyl) ethyl 1-isothiocyanate
2-trans-4- (trans-4-octylcyclohexyl) cyclohexyl) ethyl 1-isothiocyanate
3-trans-4- (trans-4-ethylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
3-trans-4- (trans-4-propylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
3-trans-4- (trans-4-butylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
3-trans-4- (trans-4-pentylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
3-trans-4- (trans-4-hexylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
3-trans-4- (trans-4-heptylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
3-trans-4- (trans-4-octylcyclohexyl) cyclohexyl) propyl-1 isothiocyanate
5-ethyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-propyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-butyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-pentyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-hexyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-heptyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-octyl-2- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-ethyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-propyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-butyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-pentyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-hexyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-heptyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
2-octyl-5- (4- (2-isothiocyanatoethyl) phenyl) pyrimidine
5-ethyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
5-propyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
5-butyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
5-pentyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
5-hexyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
5-heptyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
5-octyl-2- (4-isothiocyanatomethylphenyl) pyrimidine
2-ethyl-5- (4-isothiocyanatomethylphenyl) pyrimidine
2-propyl-5- (4-isothiocyanatomethylphenyl) pyrimidine
2-butyl-5- (4-isothiocyanatomethylphenyl) pyrimidine
2-pentyl-5- (4-isothiocyanatomethylphenyl) pyrimidine
2-hexyl-5- (4-isothiocyanatomethylphenyl) pyrimidine
2-heptyl-5- (4-isothiocyanatomethylphenyl) pyrimidine
2-octyl-5- (4-isothiocyanatomethylphenyl) pyrimidine

Example 2

30.5 g of 4- (4- (4-pentylcyclohexyl) cyclohexyl) benzylamine (obtained from 4- (4- (4-pentylcyclohexyl) cyclohexyl) benzonitrile) are with 10 g of carbon disulfide and 30 ml Triethylamine in 500 ml of toluene for 30 hours at 0-10 ° C touched. Then the deposited crystal mass of the triethylammonium dithiocarbonate filtered and with Washed toluene. The intermediate product is suspended in a mixture of 500 ml of chloroform and 50 ml of triethylamine and then dropwise gives chlorocarbonic acid ethyl ester (21 g) added. After removing the excess Triethylamine with dilute hydrochloric acid and Conventional work-up gives 4- (4- (4-pentylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate.  

The following are produced analogously:
4- (4- (4-ethylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate
4- (4- (4-Propylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate
4- (4- (4-butylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate
4- (4- (4-Hexylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate
4- (4- (4-heptylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate
4- (4- (4-octylcyclohexyl) cyclohexyl) phenylmethyl isothiocyanate
3- (4- (4- (4-Ethylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate
3- (4- (4- (4-Propylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate
3- (4- (4- (4-Butylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate
3- (4- (4- (4-Pentylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate
3- (4- (4- (4-Hexylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate
3- (4- (4- (4-Heptylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate
3- (4- (4- (4-Octylcyclohexyl) cyclohexyl) phenyl) propyl-1-isothiocyanate

Example 3

A mixture of 26.4 g of 4- (4- (4-propylcyclohexyl) phenyl) benzylamine (obtained from 4- (4- (4-propylcyclohexyl) phenyl) benzonitrile), 400 ml methylene chloride and 15 ml triethylamine  is mixed with 12 g of thiophosgene and 14 hours stirred at room temperature. After usual work-up 4-isothiocyanatomethyl-4 '- (4-propylcyclohexyl) biphenyl is obtained.

The following are represented in the same way:
4-isothiocyanatomethyl-4 ′ - (4-ethylcyclohexyl) biphenyl
4-isothiocyanatomethyl-4 ′ - (4-butylcyclohexyl) biphenyl
4-isothiocyanatomethyl-4 ′ - (4-pentylcyclohexyl) biphenyl
4-isothiocyanatomethyl-4 ′ - (4-hexylcyclohexyl) biphenyl
4-isothiocyanatomethyl-4 ′ - (4-heptylcyclohexyl) biphenyl
4-isothiocyanatomethyl-4 ′ - (4-octylcyclohexyl) biphenyl
4- (2-isothiocyanatoethyl) -4 ′ - (4-ethylcyclohexyl) biphenyl
4- (2-isothiocyanatomethyl) -4 ′ - (4-propylcyclohexyl) biphenyl
4- (2-isothiocyanatomethyl) -4 ′ - (4-butylcyclohexyl) biphenyl
4- (2-isothiocyanatomethyl) -4 ′ - (4-pentylcyclohexyl) biphenyl
4- (2-isothiocyanatomethyl) -4 ′ - (4-hexylcyclohexyl) biphenyl
4- (2-isothiocyanatomethyl) -4 ′ - (4-heptylcyclohexyl) biphenyl
4- (2-isothiocyanatomethyl) -4 ′ - (4-octylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-ethylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-propylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-butylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-pentylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-hexylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-heptylcyclohexyl) biphenyl
4- (3-isothiocyanatopropyl) -4 ′ - (4-octylcyclohexyl) biphenyl

Example 4

28.0 g of 2-fluoro-4- (4-hexylcyclohexyl) benzylamine (available from 2-fluoro-4-bromobenzonitrile by lithiation at -100 ° C and reaction with 4-hexylcyclohexanone, dehydration of the tertiary alcohol and reduction of the double bond and the Nitrile group) with 12 g of thiophosgene and 25 ml of triethylamine in 300 ml of chloroform for 20 hours at room temperature touched. After the usual work-up, 2-fluoro-4- is obtained. (4-hexylcyclohexyl) phenylmethyl isothiocyanate.

The following are produced analogously:
2-fluoro-4- (4-ethylcyclohexyl) phenylmethyl isothiocyanate
2-fluoro-4- (4-propylcyclohexyl) phenylmethyl isothiocyanate
2-fluoro-4- (4-butylcyclohexyl) phenylmethyl isothiocyanate
2-fluoro-4- (4-pentylcyclohexyl) phenylmethyl isothiocyanate
2-fluoro-4- (4-heptylcyclohexyl) phenylmethyl isothiocyanate
2-fluoro-4- (4-octylcyclohexyl) phenylmethyl isothiocyanate
2- (2-fluoro-4- (4-ethylcyclohexyl) phenyl) ethyl-1-isothiocyanate
2- (2-fluoro-4- (4-propylcyclohexyl) phenyl) ethyl-1-isothiocyanate
2- (2-fluoro-4- (4-butylcyclohexyl) phenyl) ethyl-1-isothiocyanate
2- (2-fluoro-4- (4-pentylcyclohexyl) phenyl) ethyl-1-isothiocyanate
2- (2-fluoro-4- (4-hexylcyclohexyl) phenyl) ethyl-1-isothiocyanate
2- (2-fluoro-4- (4-heptylcyclohexyl) phenyl) ethyl-1-isothiocyanate
2- (2-fluoro-4- (4-octylcyclohexyl) phenyl) ethyl-1-isothiocyanate
3- (2-fluoro-4- (4-ethylcyclohexyl) phenyl) propyl-1-isothiocyanate
3- (2-fluoro-4- (4-propylcyclohexyl) phenyl) propyl-1-isothiocyanate
3- (2-fluoro-4- (4-butylcyclohexyl) phenyl) propyl-1-isothiocyanate
3- (2-fluoro-4- (4-pentylcyclohexyl) phenyl) propyl-1-isothiocyanate
3- (2-fluoro-4- (4-hexylcyclohexyl) phenyl) propyl-1-isothiocyanate
3- (2-fluoro-4- (4-heptylcyclohexyl) phenyl) propyl-1-isothiocyanate
3- (2-fluoro-4- (4-octylcyclohexyl) phenyl) propyl-1-isothiocyanate

Example 5

A mixture of 4.8 g of 4- (4- (4- (4-pentylcyclohexyl) phenyl) phenyl) cyclohexylmethyl) - mesylate (made by lithiation of 4- (4-pentylcyclohexyl) -4′-bromobiphenyl -100 ° C and reaction with 4-oxocyclohexylcarboxylic acid ethyl ester, Dehydration of the tertiary alcohol, reduction the double bond and the ester and subsequent mesylation) 15 ml of toluene and 1.2 g of potassium rhodanide Heated to 80 ° C for 16 hours.  

After cooling and usual work-up, 4- (4- Pentycyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl.

The following are represented in the same way:
4- (4-Ethylcyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl
4- (4-propylcyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl-
4- (4-butylcyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl
4- (4-Hexylcyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl
4- (4-heptylcyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl-
4- (4-octylcyclohexyl) -4 ′ - (4-isothiocyanatomethylcyclohexyl) biphenyl
4- (4-ethylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphen-yl
4- (4-Propylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphenyl
4- (4-butylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphen-yl
4- (4-Pentylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphenyl
4- (4-Hexylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphen-yl
4- (4-heptylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphenyl
4- (4-Octylcyclohexyl) -4 ′ - (4- (2-isothiocyanatoethyl) cyclohexyl) biphen-yl
4- (4-Ethylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biphenyl
4- (4-Propylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biph-enyl
4- (4-Butylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biphenyl
4- (4-Pentylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biph-enyl
4- (4-Hexylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biphenyl
4- (4-heptylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biph-enyl
4- (4-Octylcyclohexyl) -4 ′ - (4- (3-isothiocyanatopropyl) cyclohexyl) biphenyl

The following mixtures are examples of preferred mixtures according to the invention. n means the viscosity at 20 ° in mPa · S, and K. the clearing point. All percentages refer to percentages by weight.

Mix 1

5.0% p-trans-4-propylcyclohexylbenzonitrile

15.0% trans-1-p-methoxyphenyl-4-propylcyclohexane

15.0% trans-1-p-ethoxyphenyl-4-propylcyclohexane

10.0% trans-1-p-butoxyphenyl-4-propylcyclohexane

15.0% 4-ethyl-4 ′ - (trans-4-propylcyclohexyl) biphenyl

15.0% 4-ethyl-4 ′ - (trans-4-pentylcyclohexyl) biphenyl

5.0% 4,4'-bis (trans-4-propylcyclohexyl) biphenyl

20.0% 4- (trans-4-pentylcyclohexyl) cyclohexylmethyl isothiocyanate

K. = 65 ° C,

n

= 17.  

Mix 2

15.0% trans-4- (trans-4-propylcyclohexyl) -1-methoxycyclohexane 15.0% trans-4- (trans-4-propylcyclohexyl) -1-propoxycyclohexane 10.0% trans-4- (trans-4 -Pentylcyclohexyl) -1-methoxycyclohexane 15.0% 4-ethyl-4 ′ - (trans-4-propylcyclohexyl) biphenyl 15.0% 4-ethyl-4 ′ - (trans-4-pentylcyclohexyl) biphenyl 5.0% 4 , 4'-bis (trans-4-propylcyclohexyl) biphenyl 25.0% 2- [4- (trans-4-pentylcyclohexyl) cyclohexyl] ethyl-1-isothiocyanate K. = 74 ° C, n = 17.

Claims (5)

1. Mustard oils of formula I, R- (A¹-Z¹) _n -A²-Z²-A³- (CH₂) _p -NCS (I) wherein
RH or alkyl with 1-15 C atoms, in which also one or two non-adjacent CH₂ groups by -O-, -C≡C-, -CH≡CH-, -CO-, -O-CO- and / or -CO-O- can be replaced, A¹ and A² each represent an unsubstituted or mono- or polysubstituted 1,4-cyclohexylene group, in which one or two non-adjacent CH₂ groups can also be replaced by -O- and / or -S-, a piperidine-1,4-diyl or 1,4-bicyclo [2,2,2] octylene group or an unsubstituted or by one or two F and / or Cl atoms and / or CH₃ groups and / or N₃- Groups and / or NCS groups and / or CN groups substituted 1,4-phenylene group, in which one or two CH groups can also be replaced by N, A³ an unsubstituted or mono- or polysubstituted 1,4-cyclohexylene group or an unsubstituted one or 1,4-phenylene group substituted by one or two F and / or Cl atoms and / or CH₃ groups and / or N₃ groups and / or NCS groups and / or CF₃ groups and / or CN groups, Z 1 and Z 2 each -CO-O -, -O-CO-, -CH₂CH₂-, -CHCN-CH₂-, -CH₂-CHCN-, -CH = CH-, -C≡C-, -OCH₂-, -CH₂O-, -CH = N-, -N = CH-, -NO = N-, -N = NO- or a single bond, n is 0, 1 or 2 and p is 1, 2, 3, 4, 5 or 6. 2. A process for the preparation of mustard oil of the formula I according to claim 1, characterized in that an appropriate amine is treated with thiophosgene,
or by converting an appropriate amine with carbon disulfide into a dithiocarbamate and treating it with hydrogen peroxide or a chlorocarbonic acid ester,
or that a corresponding halide of the formula I is reacted with a salt of thiocyanic acid,
or treating a compound which otherwise corresponds to the formula I but contains one or more reducible groups and / or CC bonds instead of H atoms with a reducing agent,
or that for the preparation of esters of the formula I (in which Z 1 and / or Z 2 are -CO-O- or -O-CO- and / or R contains a carboxyl group) a corresponding carboxylic acid or one of its reactive derivatives with a corresponding alcohol or one of its reactive derivatives,
or that a corresponding hydroxy compound is etherified for the preparation of ethers of the formula I (in which R is an alkoxyl group and / or Z 1 and / or Z 2 is a -OCH₂- or -CH₂O group). 3. Liquid crystalline phase with at least two liquid crystalline phases Components, characterized in that they at least one compound of formula I according to claim 1 contains. 4. liquid crystal display element, characterized in that it is a liquid crystalline phase according to claim 3 contains. 5. Electro-optical display element, characterized in that as a dielectric there is a phase according to claim 3 or 4 contains.