JPH024754A - Difluorobenzonitrile derivative - Google Patents

Abstract

NEW MATERIAL: A compound of formula I (wherein R is a 1-12C alkyl, provided that the CH₂ group existing in this group can be substituted by O, CO or the like on condition that it is not bonded to O; and A is formula II, formula III or the like).

EXAMPLE: 4-(trans-4-Pentylcyclohexyl)-2,3-difluorobenzonitrile.

USE: The derivative is used for electro-optical display element, is useful as a component of a liquid crystal phase, especially the liquid crystal phase of a display based on the principle of a twisted cell, the guest-host effect, the effect of the deformation of an alignment phase and the effect of dynamic scattering.

PROCESS: A formyl compound of formula IV (wherein X is CHO) is formulated by a known method, and the product is reacted with hydroxyamide-O-sulfonic acid to obtain a compound of formula I.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a derivative of 2,3-difluorobenzonitrile represented by the following formula 1: is a 1,4-cyclohexylene group, and PF2N is a 1,4-cyclohexylene group, in which R is C Atom 1-
an alkyl group having 12 groups, and one or two CH, groups present in this group are also -o--co--o, provided that the two oW molecules are not directly bonded to each other. −
may be replaced by co- and/or -CH═CH-, and for the sake of brevity, in the following description CyC is 1.
It represents a 4-phenylene group.

The compounds of formula 1 can be used as components of liquid-crystal phases, in particular for displays based on the twisted cell principle, the guest-host effect, the effect of ordered phase deformation or the effect of dynamic scattering.

An important criterion for multiplex operation of such cells is that the ratio of the anisotropy of the dielectric constant to the dielectric constant perpendicular to the molecular axis, i.e. Δε/ε, is small [e.g. Gharadjedag
Rev, Phas by ji et al.

Appl, p. 11467 (1976)].

To obtain a small Δε/ε soil, a conventional material with a negative Δε is mixed with a material with a positive Δε.

However, in addition to a positive Δε, it is better to use materials that have a strong transverse dipolarity.

A series of liquid crystal compounds of this type have already been synthesized, for example carboxylic acid esters of 4-cyano-2(5)-fluorophenol or 5-cyanopyridine-2
-yl compounds.

However, this 5-cyanopyridin-2-yl compound generally suffers from e.g. poor solubility in mixtures,
It has disadvantages such as high viscosity, high melting point and chemical instability. Furthermore, these compounds generally have a tendency to form higher order smectic phases. Therefore, in combination with a large dielectric constant that is perpendicular to the molecular axis, it has a positive dielectric anisotropy, which can further improve the properties of the mixture for all types of electro-optical applications. A different type of compound is needed.

The aim of the invention is to find stable liquid-crystalline or mesogenic compounds that have a positive dielectric anisotropy, a large negative lateral dipole and, at the same time, a low viscosity.

It has been found that the compound represented by formula (2) is excellently suited as a component of a liquid crystal phase. In particular, by using these compounds stable liquid crystal phases with a wide meso-7ace range and relatively low viscosities can be prepared.

The preparation of compounds of the formula (II) considerably widens the range of liquid-crystalline substances suitable for the preparation of liquid-crystalline mixtures from the point of view of various industrial applications.

The compounds of formula I have a wide range of uses. These compounds can be used as liquid crystal base materials constituting the main part of the liquid crystal phase by selecting substituents.

However, the compound represented by formula (2) can be added to a liquid crystal base material consisting of a different type of compound to improve, for example, the dielectric anisotropy and/or optical anisotropy and/or viscosity and/or The spontaneous polarization and/or phase range and/or tilt angle and/or pinch can be varied.

Furthermore, the compounds of formula I are suitable as intermediates for the production of other types of materials that can be used as components of liquid-crystalline dielectrics.

The compounds of formula I are colorless in the pure state and form liquid-crystalline membranes in the temperature range that is preferred for electro-optical applications. These metal oxides are very stable chemically, thermally and to light.

The invention therefore relates to compounds of formula I.

Furthermore, the present invention relates to the use of a compound of formula (1) as a component of a liquid crystal phase.

The invention also provides 2,3-difluoro-4 as a structural element.
The invention relates to a liquid crystal phase containing at least one compound having -cyanophenyl groups, in particular a compound of the formula I, and the invention also relates to a liquid crystal display element comprising a phase of this type. Phases of this type have particularly advantageous elastic constants and, due to their low Δε/ε1 values, are particularly suitable for TPT mixtures.

Therefore, the compound represented by formula (■) has the following subformulas Ia to I
Compound having 2 rings represented by c: R-Phe-PF2
NIaR-Cyc-PF2
N I bR-Cyc-CHt
CHz-PF2N Ic and a compound having 3 rings represented by the following subformula Id-Ih: R-Phe-Phe-PF2N I
dR-Cyc-Cyc-PF2N
I eR-Cyc-CHtCHz-Cyc-PF2N
I fR-Cyc-CH,0-Phe-
PF2N I gR-Cyc-CHzC
H2-Phe-PF2N Ih In the compound represented by the formula described throughout this specification,
R is preferably alkyl and also alkoxy.

In the formulas described herein, R preferably has 2 to 10, especially 3 to 7, C atoms.

One or two CH, groups present in the R group may also be replaced. Preferably only one CH
Two groups are 10-1-C0- or -CH=CH-1, especially -
Replaced by 0- or 10-CO-.

In the formulas described herein, R is preferably an alkyl, alkoxy or another oxaalkyl group; furthermore, R is an alkyl group in which one or more CH , the group is -o--o-c, assuming that the two heteroatoms are not directly bonded to each other.
It is a group which may be replaced by o- or -CH=CH- or by a combination of two suitable groups.

R is an alkyl group, and one CH present in this group
, when the group may be replaced by an OK child (``
``alkoxy'' or ``oxaalkyl''), or two non-adjacent CH, groups present in this group o
When optionally replaced by atoms ([alkoxyalkoxy" or "dioxaalkyl"), the group can be straight-chain or branched.

Preferably, this group is linear and C[child 2.3.4
．． 5.6 or 7 and are therefore preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or hemethoxy; furthermore, R is methyl, off “Tyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, tunoxy, decoxy, undecoxy,
Dodecoxy, tridecoxy or tetradecyl.

Oxaalkyl is preferably linear 2-oxypropyl(-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, 2-3-4-56- or 7-oxaoctyl, 2-34-5-6-7
- or 8-oxanonyl, 2- 3- 4- 5-
6-7-8- or 9-oxadecyl, 1.3-dioxabutyl(-methoxymethoxy), 1.3-1.4
- or 2,4-dioxapentyl, l, 3-11.4
=1.5-12.4-12,5- or 3.5-dioxahexyl, or l, 3-11.4- 1.5-
1.6-2.4-12.5-12.6-13.5-13
, 6- or 4,6-thioxaheptyl.

R is an alkyl group, and one CH present in this group
, is replaced by -CH=CH-, this radical can be straight-chain or branched.

Preferably, this group is linear and has from 2 to IO children. Therefore, this group is particularly suitable for vinyl, prop-1
- or -2-enyl, budo l- -2- or -3-
Bent-1--2-3- or -4-enyl, Hex-1--2-3-4- or -5-enyl, Hept-1-2-3-4 -5- or -6-enyl, oct-1-2-3-4-5-6- or -7-enyl, non-1-7- or -8-enyl or dec-1 -7--8- or -9-enyl.

R is an alkyl group, and one (H
, is replaced by 10-CO- or -CO-O-, this radical can be linear or branched. Preferably, this group is linear;
It has 2 to 6 C atoms.

Thus, this group includes in particular acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyl Oxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxyethyl,
4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2-, (methoxycarbonyl)ethyl, 2-( ethoxycarbonyl)
Ethyl, 2-(propoxycarbonyl)ethyl, 3-(
Methoxycarbonyl)propyl, 3-(ethoxycarbonyl)propyl or 4-(methoxycarbonyl)butyl.

Compounds of formula I with branched groups R are sometimes of interest as they have good solubility in customary liquid crystal substrates, but if they are optically active chiral doping agents This is particularly important. Smectic compounds of this type are suitable as components for ferroelectric materials.

Branched groups of this type generally have at most one chain branch. Suitable branched groups R1 are isopropyl, 2-butyl (-1-methylpropyl), isobutyl (=2-methylpropyl), 2-methylbutyl, impentyl (-3
-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-7'-pyrupentyl, impropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3 -Methylpentoxy, 2-ethylhexoxy, l-
Methylhexoxy, ■-Methylhebutoxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-nonyl, 2-decyl, 2-
Dodecyl, 6-methyloctoxy, 6-methyloctanoyloxy, 5-methylhebutyloxycarbonyl, 2
-methylbutyryloxy, 3-methylvaleryloxy,
4-methylhexanoyloxy, 2-chloropropionyloxy, 2-chloro-3-methylbutyryloxy, 2
-chloro-4-methylvaleryloxy, 2-chloro-3
-methylvaleryloxy, 2-methyl-3-oxapentyl or 2-methyl-3-oxahexyl.

R is an alkyl group, and two or more CH, groups present in this group are 10- and (or) -CO-
When replaced by O-, this group can be straight-chain or branched. Preferably, this group is branched and has 3 to 12 CyKs. Thus, this group is especially suitable for bis-carboxy-methyl, 2.
2-bis-carboxy-ethyl, 3.3-bis-carboxy-propyl, 4.4-bis-carboxy-butyl,
5.5-bis-carboxy-pentyl, 6,6-biscarboxy-hexyl, 7,7-bis-carboxy-heptyl, 8.8-bis-carboxy-octyl, 9.9-
His-carboxy-nonyl, 10.10-bis-carboxy-decyl, bis-(methoxycarbonyl)-methyl, 2.2-bis-(methoxycarbonyl)-ethyl, 3
．． 3-bis-(methoxycarbonyl)-propyl, 4.
4-bis-(methoxycarbonyl)-butyl, 5,5-
Bis-(methoxycarbonyl)-pentyl, 6.6-bis-(methoxycarbonyl)-hexyl, 7.7-bis-(methoxycarbonyl)-heptyl, 8.8-bis=
(methoxycarbonyl)-octyl, bis-(ethoxycarbonyl-(ethoxycarbonyl)-ethyl, 3.3-bis-
(Ethoxycarbonyl)-propyl, 4,4-bis-(
ethoxycarbonyl)-butyl or 5. -5-bis-(ethoxycarbonyl)-pentyl.

Formula I, in which the terminal group R is a group suitable for use in polycondensation
The compound represented by is suitable for producing liquid crystal polycondensates.

Formula I is intended to encompass both the racemic and optically opposed forms of these compounds, as well as mixtures thereof.

Among the compounds of formula I and also formulas Ia-Ie,
Compounds in which at least one of the groups contained in the molecule has one of the preferred meanings mentioned above are preferred compounds.

A narrow group of preferred compounds of formula I is represented by the following subformula 11-I23: Alkyl-Phe -
PF2N alkoxy-Phe - PF2N alkanoyloxy-Phe - PF2N alkoxycarbonyl-Phe - PF2N alkyl-Cyc
- PF2N alkoxy-Cyc - PF2N alkanoyloxy-Cyc - PF2N alkoxycarbonyl-Cyc - PF2N alkyl-Cyc
- CH2Cl, - PF2N alkoxy-Cyc
CHzCHz-PF2N alkanoyloxy-Cyc
CH2CH2 PF2N alkoxycarbonyl-
Cyc CHzCHz PF2N alkyl-Phe
- Phe - PF2N alkoxy-Phe -
Phe - PF2N alkanoyloxy-Phe -
Phe - PF2N alkoxycarbonyl-Phe
- Phe - PF2N alkyl-Cyc - C
yc-PF2N alkoxy-Cyc-Cyc
- PF2N alkanoyloxy-Cyc - Cyc
- PF2N alkoxycarbonyl-Cyc - C
yc - PF2Nt Engineering 2 I3 I6 Engineering 9 l1 Alkyl-Cyc-CH,CH, -Cyc-PF2N
I 21 alkyl-Cyc-CH*O-
Pha-PF2N I 22alkyl-Cyc-CHtCJ-Phe PF2N
r 23 The compound represented by formula I is described in the literature [
For example, the Method by Houben-Weyl
n der Organischen Chemie (G
eorg-Thien+a Publisher, Stuttgart
They can be prepared by methods known per se, such as those described in standard scientific texts such as J.D.C.), in particular under known reaction conditions suitable for the reactions mentioned. In this case, it is also possible to use variants that are known per se and are not described in detail here.

If desired, the starting compounds can also be produced in situ in such a way that upon their isolation from the reaction mixture, they are immediately further reacted to produce the compounds of formula I.

Compounds of formula I are preferably prepared from compounds of formula 1 below: Formyl compounds of formula
and A have the meaning given above, and x is H, CL C
HO or C0OH"C').

A difluorobenzene derivative represented by the formula ■ (wherein X-
H) can be deprotonated using organometallic compounds or base systems in a manner known per se [this method is described, for example, in A. M. Roe et al. J. Ch.
em, Soc, Chem, Comm.

(1965)].

The corresponding lithium compounds can be formylated using formamides such as dimethylformamide or N-formylpiperidine, (X-CHO), or carboxylated using carbon dioxide, giving (X-CHO) COOH), or can be reacted directly using cyanogen chloride or cyanogen bromide to produce compounds of formula I.

It can be converted into the nitrile compound of formula 1 by known methods [for example, J. 5treith et al., He1v, Acta 59.2786 (1976)].
According to the method described in].

Suitable organometallic compounds are in particular organolithium compounds, such as tetrahydrofuran, dioxane or jerk
-ethers such as butyl methyl ether, hexane,
n-te in an inert solvent such as a hydrocarbon such as benzene or toluene, or a mixture of these solvents.
Examples include rt- or 5ec-butyllithium or methyllithium. Preferably, a complexing agent is used, such as an amine such as tetramethylethylenediamine (TMEDA), or hexamethylphosphoric triamide (HMPT).
) or N,N-dimethylpropylene urea (DMPH)
Amides such as can be added to these solvents.

Usually, the reaction temperature is -120°C to -10°C, preferably -100°C to -50°C.

At these temperatures, the deprotonation reaction is generally 1-
Completed after 10 hours.

Furthermore, the compound of formula I preferably comprises an organic titanium or an organic anine compound with 4-furomo(chloro)
-2,3-difluorobenzonitrile compounds in the presence of metal catalysts (for this process see, for example, DE 3,736.489 and DE 3.632.410).

Compounds of formula I also include, in formula 1, instead of the HIM group, one or more reducible groups and (
or) can be produced by reducing a corresponding compound having a C--C bond.

Reducible groups that can be used are preferably carbonyl groups,
In particular, it is a keto group, and also, for example, a free or esterified hydroxyl group or a halogen atom bonded to an aromatic group. Suitable starting compounds for this reduction include, in formula I, in place of the cyclohexane ring:
It can have a cyclohexene ring or a cyclohexanone ring, and (or) it can have a -CH=CH- group instead of a -CH2CHz- group, and (or) it can have -C〇- instead of a -C1,- group. Corresponding compounds which can contain groups and/or have a free or functionally modified OH group (for example in the form of its p-toluenesulfonate) instead of an H atom.

The reduction is carried out, for example, at a temperature of about θ° to about 200°,
Under a pressure of 200 bar, an inert solvent such as an alcohol such as methanol, ethanol or impropatol, an ether such as tetrahydrofuran (THF) or dioxane, an ester such as ethyl acetate, a carboxylic acid such as acetic acid or cyclohexane It can be carried out by catalytic hydrogenation in hydrocarbons such as. Suitable catalysts are preferably noble metals such as Pt or Pd, in the form of oxides (e.g. PtO,
or Pd0), on a support (for example Pd on charcoal, calcium carbonate or strontium carbonate) or in finely divided form.

Ketone compounds can also be prepared by the method of Clemmensen, in which anine, anine amalgam or tin and hydrochloric acid are mixed at about 80-120°, preferably in an aqueous-alcoholic solution or in a heterogeneous phase system using water/toluene.
temperature) or Wolf f-K15
Hner's method, in which hydrazine is heated at about 100-200° in a high boiling solvent such as diethylene glycol or triethylene glycol, preferably in the presence of an alkali such as KOH or NaOH.
of formula I with an alkyl group and/or -CHz (Jli-bridge)
The corresponding compound shown can be produced.

Furthermore, reduction with complex hydrides can also be used. - As an example, arylsulfonyloxy groups can be reductively separated using LiAffH, in particular:
A p-toluenesulfonyloxymethyl group can be reduced to a methyl group, preferably in an inert solvent such as diethyl ether or THF at a temperature of about 0 to 100'. A double bond (even if a CN group is present)
, NaBH in methanol, or tributyl-tin hydride.

To prepare the nitrile compounds of formula I, the corresponding acid amide compounds can be dehydrated. The amide compounds are obtained, for example, from the corresponding ester compounds or acid halide compounds by reaction with ammonia. Examples of suitable dehydrating agents include 5OCI22, pca
,,pcQ,,pocI2. , so, cQ, or G
OCf: Inorganic acid chlorides such as and also P2O
3, p, s AQCQ3 compounds are, for example, NaC
(used as a complex compound with Q), aromatic sulfonic acids and sulfonylic acid halides. In this case, the reaction is carried out in the presence of an inert solvent or in the absence of about 0
It can be carried out at temperatures between 150° and 150°. Examples of solvents that can be used include bases such as pyridine or triethylamine, aromatic hydrocarbons such as benzene, toluene or xylene, or amides such as DMF.

To prepare said nitrile compounds of formula I, the corresponding acid halide compound, preferably chloride, is heated with sulfamide, preferably in an inert solvent such as tetramethylene sulfone, at a temperature of about 80° to 150°. The reaction can be carried out at a temperature, preferably 120°. The nitrile compounds can be isolated directly after working up in the usual manner.

In addition to one or more compounds according to the invention, the liquid crystal medium according to the invention preferably contains 2 to 40, in particular 4 to 30, components as further components. These mediums very particularly preferably contain, in addition to the above, from 7 to 25 components of one or more compounds according to the invention. These additional components are preferably nematic or nematogenic (monomodified or isotropic) substances, in particular azoxybenzene compounds, benzylideneaniline compounds, biphenyl compounds, terphenyl compounds, phenyl or cyclohexylbenzoate compounds,
Phenyl or cyclohexylcyclohexanecarboxylate compounds, 7-enyl or cyclohexyl ester compounds of cyclohexylbenzoic acid, phenyl or cyclohexyl ester compounds of cyclohexylcyclohexanecarboxylic acid, cyclohexyl phenyl ester compounds of benzoic acid, cyclohexyl cyclohexanecarboxylic acid Phenyl ester compound, cyclohexylcyclohexane carboxylic acid cyclohexyl phenyl ester compound, phenylcyclohexane compound, cyclohexyl biphenyl compound, phenylcyclohexylcyclohexane compound, cyclohexylcyclohexane compound, cyclohexylcyclohexene compound, cyclohexylcyclohexyl Cyclohexene compound, 1,4-bis-cyclohexylbenzene (l compound, 4,4'-bis-cyclohexylbiphenyl compound,) Uniru or cyclohexylpyrimidine compound, phenyl- or cyclohexyldioxane compound, phenyl- or cyclohexyl -1,3-dithiane 6 compounds, 1,2-diphenylethane compounds, 1,2-dicyclohexylethane compounds, l-phenyl-2-cyclohexylethane compounds,
■-Cyclohexyl-2-(4-phenylcyclohexyl)-ethane compound, 1-cyclohexyl-2-biphenylethane compound, l-phenyl-2-cyclohexylphenylethane compound, optionally halogenated selected from the group of stilbene compounds, benzylphenyl ether compounds, tolan compounds and substituted cinnamic acid compounds.

The most important compounds suitable as separate components of the medium according to the invention have characteristics that can be illustrated by the following formulas 1, 2.3.4 and 5: R'-L-E-R'1 R'-L- Coo-E-R “2R
'-L-00C-E-R“
3R'-L-CH2CH2-E-R"
4R'-L-Cmi C-E-R"
5 formula 11 formula 2, formula 3,
In formulas 4 and 5, L and E can be the same or different, and independently of each other, -Phe-
1-Cyc-1-Phe-Phe-1-Phe-Cyc
-1-Cyc-Cyc-1-Pyr-1-Dio-1-
It is a divalent group belonging to the group consisting of G-Phe- and -〇-Cyc- and their mirror image groups, and Phe is 1,
4-phenylene, this group is unsubstituted or substituted with fluorine, and CyC is toran7! , −
1,4-cyclohexylene or 1,4-cyclohexenylene, Pyr is pyrimidine-2,5-diyl or pyridine-2,5-diyl, and Dio is 1.3
-dioxane-2,5-diyl, and G is 2-
(trans-1,4-cyclohexyl)-ethyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl.

Preferably, one of the groups and group E is Cyc, .
Phe or Pyr. E is preferably Cyc,
Phe or Phe-Cyc.

The medium according to the invention preferably has the formula 112.3.4
and 5, the group and the group E present in the molecule are simultaneously combined with one or more components selected from the corresponding compounds selected from the group consisting of CycSPhe and Pyr, and formulas 1, 2.3. In 4 and 5,
One of the groups and groups E present in the molecule is C
ycSPhe and Pyr, and the other one of the groups E and -Phe-Phe
-1-Phe-Cyc-1-Cyc-Cyc-1-G-
One or more components selected from the corresponding compounds selected from the group consisting of Phe- and -G-Cyc- and optionally groups present in the molecule of formulas 1, 2.3.4 and 5. and the group E is -Phe-C
yc-1-Cyc-Cyc-1-G-Phe- and -
Contains one or more components selected from the corresponding compounds selected from the group consisting of 〇-Cyc-.

In the compounds of sub-formulas 1ax 2a, 3as 4as and 5a R' and R# are each independently of one another alkyl, alkenyl, alkoxy, alkenyloxy or alkanoyloxy having up to 8 carbon atoms. . In most of these compounds R/ and R' are different from each other and one of these groups is usually alkyl or alkenyl.

In compounds represented by sub-formulas 1b, 2b, 3b, 4b and 5b, R# is -CN, -CF,, Fl.CQ
or -NC3, in which case R' is subformula 1a
- has the meanings given above for the compounds represented by 5a,
Preferred is alkyl or alkenyl. However, various other substituents proposed in compounds of formulas 1.2.3.4 and 5 are also customary.

A number of such materials or mixtures thereof are commercially available. All of these substances can be obtained by methods known from the literature or by analogous methods.

The medium according to the invention contains compounds 11%21%3a,4
In addition to the components from the group consisting of a and 5a (group l),
Preferably compounds 1b and 2b.

Contains components from the group consisting of 3b14b and 5b (group 2), the proportions of which are preferably as follows: Group 1: 20-90%, especially 30-90% Group 2: 10-90%
80%, in particular 10-50% and the sum of the proportions of compounds according to the invention and compounds from group I and group 2 is 100%.
up to %.

The medium according to the invention preferably contains from 1 to 40% of the compound according to the invention, particularly preferably from 5 to 30%.

The compound according to the invention in an amount of more than 40%, in particular 45 to 9
Preferred mediums according to the invention preferably contain three, four or three compounds according to the invention in an amount of 0%.

The medium according to the invention is prepared in a manner customary per se. Generally, the components are dissolved in each other, preferably at elevated temperatures. The liquid crystal phases according to the invention can be modified by using suitable additives in such a way that they can be used in all liquid crystal display elements of the hitherto disclosed type.

Such additives are known to those skilled in the art and can be found in the literature (
Handboo by H, Kelker/R, Hatz
kof 1iquid Crystals, Verl
ag Chemie, Wein-heimS1980
(2013). For example, colored guest −
Pleochroic dyes can be added to create a host system, or substances can be added to change the dielectric anisotropy, viscosity and/or orientation of the nematic phase.

The following is intended to explain the invention without limiting it. m, p, - melting point; c, p.

= clear point. Throughout this specification, percentages are by weight.

All temperatures are in degrees Celsius.

The term "work up in a conventional manner" shall have the following meaning: adding water and extracting the mixture with methylene chloride;
The organic phase is separated, dried and evaporated, and the product is purified by crystallization and/or chromatography.

Furthermore, C is the crystalline solid state, S is the smectic phase (the index characterizes the type of phase), N is the nematic state, Ch is the cholesteric phase, and I is the isotropic phase. It is for use. The number between the two symbols indicates the transition temperature in degrees Celsius.

Example 1 Preparation of 4-alkyl-4'-cyano-2',3'-difluorobiphenylene compound a) l-(4-pentylcyclohex-1-enyl)-
0.525 n-butyllithium in 320 mQ of 2,3-difluorobenzene hexane
The molar solution is added at -78 DEG C. to a mixture of 0.5 mol of l,2-difluorobenzene, 1000 ml of tetrahydrofuran and 0.5 mol of tetramethylethylenediamine. After stirring for 3 hours at -60°C, 0.525 mol of 4-pentylcyclohexanone dissolved in 100 mQ of tetrahydrofuran was added dropwise and the mixture was allowed to warm to room temperature.
Warm slowly. Without purifying the alcohol product obtained after neutralization, 2 g of p-1' sulfonic acid was dissolved in 250 ml of toluene and using a water separator.
and overheat for 3 hours.

Work-up in a conventional manner to give 1-(4-pentylcyclohex-1-enyl)-2,3-difluorobenzene, boiling point: 123° C. 10,5 torr.

Similarly, 1-(4-(4-
7'-pylphenyl)-cyclohex-1-enyl)-
2,3-'; Fluorobenzene is obtained.

b) 4-(4-pentylcyclohex-1-unyl)
-2,3-Difluorobenzaldehyde tetrahydrofuran 0.12 mol of N-formylpiperidine in 20 mQ of furan was added to 4-(4-pentylcyclohex-1-enyl)-2,3-difluorophenyl at 70°C. 0.1 mol of lithium (this compound is prepared from a benzene compound using n-butyllithium in tetrahydrofuran/tetramethylethylenediamine in a similar manner to Example 1a) is added and the mixture is allowed to stand for 1 hour. 2
Warm to 0°C. acidified and then worked up in the customary manner,
The title aldehyde product is obtained.

c) 4-(4-pentylcyclohex-1-enyl)-
A mixture of 0.12 mol of 2,3-difluorobenzonitrilehydroxylamine-0-sulfonic acid and 50 mff of water is added at 30'O to a mixture of 0.1 mol of the above aldehyde compound and 100 mff of water.

After stirring for 1 hour at room temperature, the mixture was heated at 65°C for 2 hours.
Warm to. Allow to cool and then work up in conventional manner to obtain the title nitrile product as a white solid.

d) Oxidation using 2.3-dichloro-5,6-dicyazbenzoquinone (DDO) 0.2 mol of DDQ is added to a mixture of 0.1 mol of the cyclohexene derivative from example 1c) and toluene 200+II+2 and the mixture is Heat and boil for 2 hours. Allowed to cool and then worked up in a conventional manner to give 4-pentyl-4
'-Cyano-2',3'-difluorobiphenyl is obtained.

Similarly, the following compound is prepared: 4-ethyl-4
'-cyano-2', 3'-difluorobiphenyl 4-propyl-4'-cyano-2', 3'-difluorobiphenyl 4-butyl-4'-cyano-2', 3'-difluorobiphenyl 4-hexyl- 4'-cyano-2', 3'-difluorobiphenyl 4-hebutyl-4'-cyano-2', 3'-difluorobiphenyl 4-octyl-4'-cyano-2', 3'-difluorobiphenyl 4- Ethoxy-4'-cyano-2', 3'-difluorobiphenyl 4-propoxy-4'-cyano-2', 3'-difluorobiphenyl 4-butoxy-4'-cyano-2', 3'-difluorobiphenyl 4 -Pentoxy-4'-cyano-2', 3'-difluorobiphenyl 4-hexoxy-4'-cyano-2', 3'-difluorobiphenyl 4-hebutoxy-4'-cyano-2', 3'-difluoro biphenyl 4-ctoxy-4'-cyano-2',3'-difluorobiphenyl 4"-ethyl-4-cyano-2,3-difluoroterphenyl 4"-propyl-4-cyano-2,3-difluoroter Phenyl 4"-butyl-4-cyano-2,3-difluoroterphenyl 4"-pentyl-4-cyano-2,3-difluoroterphenyl 4"-hexyl-4-cyano-2,3-difluoroterphenyl 4#-Hebutyl-4-cyano-2,3-difluoroterphenyl 4"-octyl-4-cyano-2,3-difluoroterphenyl 4"-ethoxy-4-cyano-2,3-difluoroterphenyl 4 "-Propoxy-4-cyano-2,3-difluoroterphenyl 4"-Butoxy-4-cyano-2,3-difluoroterphenyl 4"-Pentoxy-4-cyano-2,3-difluoroterphenyl 4 “-hexoxy-4-cyano-2,3-difluoroterphenyl 4″-hebutoxy-4-cyano-2,3-difluoroterphenyl 4″-hexoxy-4-cyano-2,3-difluoroterphenyl 4 - (trans-4-ethylcyclohexylmethoxy)-4'-cyano-2',3'-difluorobiphenyl4- (1-trans-4-globylcyclohexylmethoxy)-4'-cyano-2',3'- Difluorobiphenyl 4-(trans-4-butylcyclohexylmethoxy)-4'-cyano-2',3'-difluorobiphenyl 4-(trans-4-pentylcyclohexylmethoxy)-4'-cyano-2',3' -difluorobiphenyl 4-(trans-4-hexylcyclohexylmethoxy)-4'-cyano-2',3'-difluorobiphenyl 4-(trans-4-hexylcyclohexylmethoxy)-4'-cyano- 2',3'-difluorobiphenyl 4-(trans-4-octyldicyclohexylmethoxy)-4'-cyano-2',3'-difluorobiphenyl 1-(4'-cyano-2',3'- 1-(4'-cyano-2',3'-difluorobiphenyl-4-yl)-2-(trans -4-propylcyclohexyl)-ethane 1-(4'-cyano-2', 3'-difluorobiphenyl-4-yl)-2-(trans-4-butylcyclohexyl)-ethane 1-(4'-cyano- 2', 3'-difluorobiphenyl-4-yl')-2-(trans-4-pentylcyclohexyl)-ethane 1-(4'-cyano-2', 3'-difluorobiphenyl-4-yl') - 2-(1-trans-4-hexylcyclohexyl)-ethane 1-(4'-cyano-2',3'-difluorobiphenyl-4-yl)-2-(trans-4-hebutylcyclohexyl)-ethane 1 -(4'-cyano-2',3'-difluorobiphenyl-4-yl) -2-(1-lance-4-octylcyclohexyl)-ethane Example 2 4-cyclohexyl-2,3-difluorobenzonitrile Preparation of compound 4-(4-pentylcyclohex-1-unyl)-2,
0.1 mol of 3-difluorobenzonitrile (this compound is prepared according to Examples 1a)-1c)), palladium/
Activated carbon (1%) 1.0g and toluene 150m (2
The mixture is hydrogenated to saturation at room temperature. filter,
After removing the solvent, the residue was dissolved in dimethyl sulfoxide 1
Potassium tart-butoxide dissolved in 50mff
2 g are added and the mixture is stirred at room temperature for 2 hours. Acidification and then working up in a customary manner gives 4-() lance-4-pentylcyclohexyl)-2,3-difluorobenzonitrile.

Similarly, the following compound is prepared: 4-(trans-4-ethylcyclohexyl)-2,3-difluorobenzonitrile 4-(trans-4-propylcyclohexyl)-2,
3-difluorobenzonitrile 4-(1-lanse-4-
butylcyclohexyl)-2,3-difluorobenzonitrile 4- (trans-4-hexylcyclohexyl)-2
,3-difluorobenzonitrile 4-()lans-4-
hebutylcyclohexyl)-2,3-difluorobenzonitrile 4-(1-lance-4-octylcyclohexyl)-2,3-difluorobenzonitrile 4-(1-
trans-4-ethoxycyclohexyl)-2,3-difluorobenzonitrile 4-(trans-4-propoxycyclohexyl)-2,3-difluorobenzonitrile 4- (trans-4-butoxycyclohexyl) -
2,3-difluorobenzonitrile 4-(trans-4
-benoxycyclohexyl)-2,3-difluorobenzonitrile 4-()trans-4-hexoxycyclohexyl)-2,3-difluorobenzonitrile 4-(trans-4-hebutoxycyclohexyl)-2,3-difluoro Benzonitrile 4-(trans-trans-4
-ethylbicyclohexyl-4'-yl)-2,3-difluorobenzonitrile 4-(trans-trans-4-propylbicyclohexyl-4'-yl)-2,3-difluorobenzonitrile 4-(trans -trans-4-butylbicyclohexyl-4'-yl)-2,3-difluorobenzonitrile 4-(1-trans-trans-4-pentylbicyclohexyl-4'-yl)2,3-difluorobenzo Nitrile 4- (trans-trans-4-hexylbicyclohexyl-4'-yl)-2,3-difluorobenzonitrile 4- (trans-trans-4-hexylbicyclohexyl-4'-yl)- 2,3-difluorobenzonitrile 4-(trans-trans-4-octylbicyclohexyl-4'-yl)-2,3-'; fluorobenzonitrile 4-[trans-4-(trans-4-ethylcyclohexyl) ethyl)cyclohexyl]2,3-difluorobenzonitrile 4-[trans-4-(trans-4-probyldikulohexylethyl)cyclohexyl-2,3-difluorobenzonitrile 4-[trans-4-(trans-4- butylcyclohexylethyl)cyclohexyl]2,3-difluorobenzonitrile 4-[trans-4-(trans-4-pentylcyclohexylethyl)cyclohexyl]-2,3-difluorobenzonitrile 4-[trans-4-(trans-4 -hexylcyclohexylethyl)cyclohexyl]-2,3-difluorobenzonitrile 4-[trans-4-(trans-4-heptylcyclohexylethyl)cyclohexyl]-2,3-difluorobenzonitrile 4-[trans-4-(trans -4-octylcyclohexylethyl)cyclohexyl]2.3-difluorobenzonitrile Example 3 4-[2-(trans-4-alkylcyclohexyl)-ethyl] -2,3-difluorobenzonitrile production a) l-( A solution of 0.21 mol of n-butyllithium in 30 mQ L of 2,3-difluorophenyl)-2trans-4-pentylcyclohexyl)-ethanehexane was added at 100°C to 0.25 mol of 1,2-difluorobenzene, potassium Lert-butoxide 0.20
mol and tetrahydrofuran 200+Q. After stirring for 10 minutes, a mixture of 0.2 mol of 2-(trans-4-pentylcyclohexyl-dityl iodide, 0.2 mol of dimethylaminopropylene urea and 50 mQ of tetrahydrofuran) was added to the mixture.
Add at °C. Stir for 1 hour at -40°C and then work up in conventional manner to obtain the title ethane derivative having a boiling point of 10.5 torr at 135°O. Furthermore, it has C 64°O N 106.7°■ as a by-product,
A small amount of 1,4-di(2-trans-4-pentylcyclohexyl)-ethyl)-2,3-difluorobenzene is obtained.

b) 4-[2-(trans-4-pentylcyclohexyl)-ethyl]-2,3-difluorobenzonitrile.

0.1 mol of the ethane derivative of a) is deprotonated analogously to Example 1a), formylated according to Example 1b) and then reacted according to Example 1c) with 0.12 mol of hydroxylamine-0-sulfonic acid. Work-up in a conventional manner to obtain the title nitrile compound as a colorless solid.
C38°N (t6.3') Similarly, the following compound is prepared: 4-(2-(trans-4-ethylcyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4-(2-( trans-4-propylcyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-(1-trans-4-butylcyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-( 1-trans-4-hexylcyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-(trans-4-hebutylcyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2- (trans-4-octylcyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-(trans-4-ethoxycyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-() trans-4-propoxycyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-(trans-4-butoxycyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-(trans- 4-Pentoxycyclohexyl)-ethyl)-2,'3-difluorobenzonitrile 4- (2-() lance-4-hexoxycyclohexyl)-ethyl)-2,3-difluorobenzonitrile 4- (2-( Trans-4-heptoxycyclohexyl)-ethyl)-2',3-difluorobenzonitrile 4-(2-(trans-4-octoxycyclohexyl)-ethyl)-2,3-difluorobenzonitrile Example 4 4-Alkyl Preparation of -2',3'-difluoro-4'-cyanobiphenylene compound 0.1 mol of chlorotriinpropyl orthotitanate in 20 ml of tetrahydro7ran was added at 5°C to l-
Bromomagnesium-4-propylbenzene (this compound is prepared from 0.1 mol of 4-globy-promobenzene and 0.1 mol of magnesium) is added to a mixture of 90 ml (l) of tetrahydrofuran and the mixture is heated between 5° and 2
Stir for 30 minutes at 0°C. To this mixture was added 1.
3 g and 0.1 mol (this compound is converted from l-1-limethylsilyl 2,3-difluorobenzene into the nitrile in analogy to Examples 1a) to lc) and subsequently brominated with bromine, during which time the product (prepared by distilling off trimethylsilyl bromide).

Stir at room temperature for 24 hours, then work up in the conventional manner, 4
-Propyl 2',3'-difluoro-4'-cyanobiphenyl is obtained.

Similarly, the following compound is prepared: 4-ethyl-2
', 3'-difluoro-4'-cyanobiphenyl 4-butyl-2', 3'-difluoro-4'-cyanobiphenyl 4-pentyl-2', 3'-difluoro-4'-cyanobiphenyl 4-hexyl -2',3'-difluoro-4'-cyanobiphenyl-4-hebutyl-2',3'-difluoro-4'-cy4-
Bromo-2,3-difluorobenzonitrile anobiphenyl 4-octyl-2',3'-difluoro-4'-cyanobiphenyl Example A 2,3-difluoro-4-(trans-4-propylcyclohexylethyl) -Benzonitrile 15%, 2.3-difluoro-4-(trans-4-butylcyclohexylethyl)-benzonitrile 15%, 2.3-difluoro-4-(trans-4-pentylcyclohexylethyl)-benzonitrile lO %, trans-4-propylcyclohexyltrans-sylate 9%, trans-4-pentylcyclohexyltrans-4-
7' hexane-poxylate 9%, p-propylphenyltrans-4-Ctrans-4
-propylcyclohexyl)-cyclohexane-carboxylate 6%, p-pentylphenyltrans-4- ()trans-4
-propylcyclohexyl)-cyclohexane-carboxylate 6%, p-pentylphenyltrans-4- (trans-4
-butylcyclohexyl)-cyclohexane-carboxylate 6%, p-propylphenyltrans-4-(trans-4-
butylcyclohexyl)-cyclohexane-carboxylate 6%, p-trans-4-propylcyclohexylphenyltrans-4-butylcyclohexanecarboxylate
6%, p-5-4-propylcyclohexylphenyl trans-4-pentylcyclohexane-carboxylate 6%, 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl 3% and 4- () lance-4-pentylcyclohexyl)-4
'-(trans-4-propylcyclohexyl)-2-
A nematic liquid crystal mixture consisting of 3% fluorobiphenyl is prepared.

Example B p-1-lance-4-propylcyclohexyl-benzonitrile 15%, 4-ethyl-2',3'-difluoro-4'-cyanobiphenyl 8%, 4-propyl-2'. 3'-difluoro-4'-cyanobiphenyl 7%, 4-butyl-2',3'-difluoro-4'-cyanobiphenyl 8%, p-methoxyphenyltrans-4-propylcyclohexanecarboxylate 5%, p- Ethoxyphenyltrans-4-propylcyclohexanecarboxylate p-methoxyphenyltrans-4-propylcyclohexanecarboxylate 5%, p-ethoxyphenyltrans-4-butylcyclohexanecarboxylate
4%, p-ethoxyphenyltrans-4-pentylcyclohexanecarboxylate 4%, p-methoxyphenyltrans-4-pentylcyclohexanecarboxylate 4%, p-propylphenyltrans-4-
(trans-4-propylcyclohexyl)-cyclohexanecarboxylate 6%, p-pentylphenyltrans-4-(trans-4-
propylcyclohexyl)-cyclohexanecarboxylate 6%, p-pentylphenyltrans-'4-(trans-4
-butylcyclohexyl)-cyclohexanecarboxylate 5%, p-propylphenyltrans-4- (trans-4
-butylcyclohexyl)-cyclohexanecarboxylate 5%, p-propylphenyl p-trans-4-propylcyclohexylbenzoate 8% and p-propylphenyl p-trans-4-pentylcyclohexylbenzoate 6%. Characterize the mixture

Claims (6)

[Claims] (1) Formula I ▲There are mathematical formulas, chemical formulas, tables, etc.▼ I [In the formula, R is an alkyl group having 1 to 12 C atoms, and one or two CH_2 groups present in this group may also be replaced by -O-, -CO-, -O-CO- and/or -CH=CH-, as the two O atoms are not directly bonded to each other, and A ▲There are mathematical formulas, chemical formulas, tables, etc.▼▲There are mathematical formulas, chemical formulas, tables, etc.▼▲There are mathematical formulas, chemical formulas, tables, etc.▼ ▲There are mathematical formulas, chemical formulas, tables, etc.▼▲There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ] A derivative of 2,3-difluorobenzonitrile. (2) A liquid crystal phase containing a compound represented by formula I as a component. (3) A liquid crystal phase containing at least two liquid crystal components, wherein at least one component contains a 4-cyano-2,3-difluorophenyl group as a structural element. (4) The liquid crystal phase according to claim 3, wherein at least one component is a compound represented by formula I. (5) A liquid crystal display element containing the liquid crystal phase according to claim 3 or 4. (6) The electro-optic display element according to claim 5, which contains the liquid crystal phase according to claim 3 or 4 as a dielectric.