DE4137401C2 - Benzene derivatives and liquid crystalline medium - Google Patents

Description

The invention relates to new benzene derivatives of the formula I

wherein
RH, an unsubstituted, an alkyl or alkenyl radical with 1 to 15 carbon atoms which is simply substituted by CN or CF ₃ or an at least monosubstituted by halogen, where one or more CH ₂ groups in these radicals are each independently of one another by O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- can be replaced so that O atoms are not directly linked to each other,

L ¹ and L ² each independently of one another H, F or Cl A ¹ and A ² each independently of one another

• (a) trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH ₂ groups can also be replaced by -O- and / or -S-,
• (b) 1,4-phenylene, which also contains one or two CH groups can be replaced by N,
• (c) radical from the group 1,4-cyclohexenylene, 1,4-bicyclo (2,2,2) octylene, piperidine-1,4-diyl, Naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl,

where the residues (a) and (b) can be substituted by one or two fluorine,
Z ¹

and Z ²

each independently of the other -CO-O-, -O-CO-, -CH ₂

O-, -OCH ₂

-, -CH ₂

CH ₂

-, -CH = CH-, -C∼C- or a single bond, one of the radicals Z ¹

and Z ²

also - (CH ₂

) ₄

- or -CH = CH-CH ₂

CH ₂

-,
m 0, 1 or 2,
X ¹

F or Cl, and
X ²

Cl, CF ₃

, OCF ₃

or OCHF ₂

means.  

The invention further relates to the use of this Ver bonds as components of liquid crystalline media as well as liquid crystal and electro-optical display elements, which contain the liquid-crystalline media according to the invention ten.

The compounds of formula I can be used as components liquid crystalline media are used, especially for Displays based on the principle of the twisted cell, the Guest-host effect, the effect of deformation erect Phases or the effect of dynamic scattering.

The invention was based, new stable task to find liquid-crystalline or mesogenic compounds, which are suitable as components of liquid-crystalline media and in particular at the same time a comparatively small one Have viscosity and a relatively high dielectric Anisotropy.

It has now been found that compounds of the formula I as Components of liquid crystalline media are particularly suitable are. In particular, they are comparatively low Viscosities. With their help, stable liquid crystalline media with a wide mesophase range and advantageous values for the optical and dielectric Preserved anisotropy. These media also show a lot good low-temperature behavior.

In WO 88/08441 compounds with a terminal OCF ₂ CF ₂ H group such. B.

described, however, too smecti at lower temperatures phases tend.

With regard to the most diverse areas of application such ger connections with high Δε, however, it was desirable other compounds with high nematogenicity are available too have precisely tailored to the respective applications have different properties.

With the provision of compounds of formula I will also generally the range of liquid crystalline Substances that are under different application techni viewpoints for the production of liquid crystalline Mixtures are suitable, considerably widened.

The compounds of formula I have a wide range of uses area of application. Depending on the choice of Substi These compounds can be used as base materials serve from which liquid-crystalline media predominate the part is composed; but it can also connect gene of formula I from liquid crystalline base materials  other classes of compounds can be added, for example the dielectric and / or optical anisotropy to influence such dielectric and / or in order to To optimize threshold voltage and / or 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 Temperaturbe rich. They are stable chemically, thermally and against light.

The invention thus relates to the compounds of Formula I and the use of these compounds as a compo nenten liquid-crystalline media. Subject of Invention are also liquid crystalline media with a Content of at least one compound of the formula I and Liquid crystal display elements, especially electro-optical ones Display elements that contain such media.

For the sake of simplicity, A ³ in the following means a radical of the formula

Cyc a 1,4-cyclohexyl residue,
Y OCF ₂ -CHX ¹ X ² .

Che a 1,4-cyclohexenylene residue, dio a 1,3-dioxane-2,5-diyl residue, dit a 1,3-dithiane-2,5-diyl residue, Phe a 1,4-phenylene residue, Pyd a pyridine-2, 5-diyl radical, Pyr a pyrimidine-2,5-diyl radical and Bi a bicyclo (2,2,2) octylene radical, where Cyc and / or Phe can be unsubstituted or mono- or disubstituted by F or CN. L is preferably F. X ¹ is preferably F and X ² F, Cl, CF ₃ or OCF ₃ .

A ² and A ² are preferably selected from the group Cyc, Che, Phe, Pyr, Pyd and Dio, preferably only one of the radicals A ¹ and A ² present in the molecule being Che, Phe, Pyr, Pyd or Dio.

The compounds of the formula I accordingly comprise compounds with two rings of the sub-formulas Ia and Ib:

RA ² -A ³ -Y Ia

RA ² -Z ² -A ³ -Y Ib.

Connections with three rings of the sub-formulas Ic to If:

RA ¹ -A ² -A ³ -Y Ic

RA ¹ -Z ¹ -A ² -Z ² -A ³ -Y Id

RA ¹ -Z ¹ -A ² -A ³ -Y Ie

RA ¹ -A ² -Z ² -A ³ -Y If

as well as compounds with four rings of the sub-formulas Ig to Im:

RA ¹ -A ¹ -A ² -A ³ -Y Ig

RA ¹ -Z ¹ -A ¹ -A ² -A ³ -Y Ih

RA ¹ -A ¹ -Z ¹ -A ² -A ³ -Y Ii

RA ¹ -A ¹ -A ² -Z ¹ -A ³ -Y Ij

RA ¹ -Z ¹ -A ¹ -Z ¹ -A ² -A ³ -Y Ik

RA ¹ -A ¹ -Z ¹ -A ² -Z ² -A ³ -Y Il

RA ¹ -Z ¹ -A ¹ -Z ¹ -A ² -Z ² -A ³ -Y Im.

These include in particular those of sub-formulas Ia, Ib, Ic, Id, Ie, If, Ii and Il preferred.

The preferred compounds of sub-formula Ia include those of sub-formulas Iaa to Iah:

R-Phe-A ³ -Y Iaa

R-Phe-A ³ -Y Iab

R-Dio-A ³ -Y Iac

R-Pyr-A ³ -Y Iad

R-Pyd-A ³ -Y Iae

R-Cyc-A ³ -Y Iaf

R-Cyc-A ³ -Y Iag

R-Che-A ³ -Y Iah.

These include those of the formulas Iaa, Iab, Iac, Iad, Iaf and Iag is particularly preferred.  

The preferred compounds of sub-formula Ib include those of sub-formulas Iba and Ibb:

R-Cyc-CH ₂ CH ₂ -A ³ -Y Iba

R-Cyc-COO-A ³ -Y Ibb.

The preferred compounds of sub-formula Ic include those of sub-formulas Ica to Ico:

R-Phe-Phe-A ³ -Y Ica

R-Phe-Phe-A ³ -Y Icb

R-Phe-Dio-A ³ -Y Icc

R-Cyc-Cyc-A ³ -Y Icd

R-Phe-Cyc-A ³ -Y Ice

R-Cyc-Cyc-A ³ -Y Icf

R-Pyd-Phe-A ³ -Y Icg

R-Pyr-Phe-A ³ -Y i

R-Phe-Pyr-A ³ -Y Ici

R-Cyc-Pyr-A ³ -Y Icj

R-Cyc-Phe-A ³ -Y Ick

R-Cyc-Phe-A ³ -Y Icl

R-Dio-Phe-A ³ -Y Icm

R-Che-Phe-A ³ -Y Icn

R-Phe-Che-A ³ -Y Ico.

These include those of the formulas Ica, Icc, Icd, Ice, Ici and Icj particularly preferred.  

The preferred compounds of sub-formula Id include those of sub-formulas Ida to Idm:

R-Phe-Z ¹ -Phe-Z ¹ -A ³ -Y Ida

R-Phe-Z ¹ -Phe-Z ¹ -A ³ -Y Idb

R-Phe-Z ¹ -Dio-Z ¹ -A ³ -Y Idc

R-Cyc-Z ¹ -Cyc-Z ¹ -A ³ -Y Idd

R-Cyc-Z ¹ -Cyc-Z ¹ -A ³ -Y Ide

R-Pyd-Z ¹ -Phe-Z ¹ -A ³ -Y Idf

R-Phe-Z ¹ -Pyd-Z ¹ -A ³ -Y Idg

R-Pyr-Z ¹ -Phe-Z ¹ -A ³ -Y Idh

R-Phe-Z ¹ -Pyr-Z ¹ -A ³ -Y Idi

R-Phe-Z ¹ -Cyc-Z ¹ -A ³ -Y Idj

R-Cyc-Z ¹ -Phe-Z ¹ -A ³ -Y Idk

R-Cyc-Z ¹ -Phe-Z ¹ -A ³ -Y Idl

R-Dio-Z ¹ -Phe-Z ¹ -A ³ -Y Idm.

The preferred compounds of sub-formula Ie include those of sub-formulas Iea to Iel:

R-Pyr-Z ¹ -Phe-A ³ -Y Iea

R-Dio-Z ¹ -Phe-A ³ -Y Ieb

R-Phe-Z ¹ -Phe-A ³ -Y Iec

R-Cyc-Z ¹ -Phe-A ³ -Y Ied

R-Cyc-Z ¹ -Phe-A ³ -Y Iee

R-Phe-Z ¹ -Cyc-A ³ -Y Ief

R-Cyc-Z ¹ -Cyc-A ³ -Y Ieg

R-Cyc-Z ¹ -Cyc-A ³ -Y Ieh

R-Phe-Z ¹ -Dio-A ³ -Y Iei

R-Pyd-Z ¹ -Phe-A ³ -Y Iej

R-Phe-Z ¹ -Pyr-A ³ -Y Iek

R-Cyc-Z ¹ -Pyr-A ³ -Y Iel

The preferred compounds of the sub-formula If include those of the sub-formulas Ifa to Ifr:

R-Pyr-Phe-Z ¹ -A ³ -Y Ifa

R-Pyr-Phe-OCH ₂ -A ³ -Y Ifb

R-Phe-Phe-Z ¹ -A ³ -Y Ifc

R-Phe-Phe-OOC-A ³ -Y Ifd

R-Phe-Phe-Z ¹ -A ³ -Y Ife

R-Cyc-Cyc-Z ¹ -A ³ -Y Iff

R-Cyc-Cyc-Z ¹ -A ³ -Y Ifg

R-Cyc-Cyc-CH ₂ CH ₂ -A ³ -Y Ifh

R-Pyd-Phe-Z ¹ -A ³ -Y Ifi

R-Dio-Phe-Z ¹ -A ³ -Y Ifj

R-Phe-Cyc-Z ¹ -A ³ -Y Ifk

R-Phe-Cyc-Z ¹ -A ³ -Y Ifl

R-Phe-Pyd-Z ¹ -A ³ -Y Ifm

R-Che-Phe-Z ¹ -A ³ -Y Ifn

R-Phe-Che-Z ¹ -A ³ -Y Ifo

R-Cyc-Phe-Z ¹ -A ³ -Y Ifp

R-Cyc-Phe-OOC-A ³ -Y Ifq

RCyc-Phe-Z ¹ -A ³ -Y Ifr.

In the compounds of the formulas above and below, Y preferably means OCF ₂ -CHF-OCF ₃ , OCF ₂ -CHFCl, OCF ₂ -CHF-CF ₃ or OCF ₂ -CHCl ₂ .

R is preferably alkyl, furthermore alkoxy. A ¹ and / or A ^{2 are} preferably Phe, Cyc, Che, Pyr or Dio. The compounds of the formula I preferably contain no more than one of the radicals Bi, Pyd, Pyr, Dio or Dit.

Also preferred are compounds of the formula I and all sub-formulas in which A ¹ and / or A ^{2 is} 1,4-phenylene which is mono- or disubstituted by F or monosubstituted by CN. In particular, these are 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene and 3,5-difluoro-1,4-phenylene as well as 2-cyano-1,4-phenylene and 3-cyano- 1,4-phenylene. In a particularly preferred embodiment, A ^{2 is} 3,5-difluoro-1,4-phenylene and m 1 or 2.

Z ¹ and Z ² preferably denote a single bond, -CO-O-, -O-CO- and -CH ₂ CH ₂ -, in the second place preferably -CH ₂ O- and -OCH ₂ -.

If one of the radicals Z ¹ and Z ^{2 is} - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ , the other radical Z ¹ or Z ² (if present) is preferably the single bond.

Preferred compounds of this type correspond to the sub-formula I '

wherein Z ² - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ - and R, A ¹ , A ² , m, L, Q, X ¹ and X ^{2 have} the meaning given for formula I. The preferred meanings for R, A ¹ , A ² , m, L, X ¹ and X ^{2 also} correspond to those for the compounds of the formula I.

m is preferably 1 or 0, particularly preferably 0.

If R is an alkyl radical and / or an alkoxy radical, it can be straight or branched. Preferably it is straight-chain, 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 tetra decoxy.

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 CH ₂ group has been replaced by -CH = CH-, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Accordingly, it means especially 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-l-, 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.

If R is an alkyl radical in which one CH ₂ group has been replaced by -O- and one has been replaced by -CO-, these are preferably adjacent. Thus, they contain an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. These are preferably straight-chain and have 2 to 6 carbon atoms.

Accordingly, they mean especially acetyloxy, propionyloxy, Butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, Propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxy carbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxy carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) butyl.

If R is an alkyl radical in which one CH ₂ group has been replaced by unsubstituted or substituted -CH = CH- and an adjacent CH ₂ group has been replaced by CO or CO-O or O-CO-, this can be straight-chain or branched . It is preferably straight-chain and has 4 to 13 carbon atoms. Accordingly, it means especially acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxy-propyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxy heptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyloxyl, Methacryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxy butyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl, 9-methacryloyloxynonyl.

If R is a monosubstituted by CN or CF ₃ alkyl or alkenyl radical, this radical is preferably straight-chain and tion substitution by CN or CF ₃ in ω-Posi.

If R is at least one substituted by halogen Alkyl or alkenyl radical, this radical is preferred as straight-chain and halogen is preferably F or Cl. At Multiple substitution is preferably halogen F. The resul residues also include perfluorinated residues. At Single substitution can be the fluorine or chlorine substituent in be in any position, but preferably in the ω position.

Compounds of formula I which are used for polymerization suitable wing groups R are suitable to represent liquid crystalline polymers.

Compounds of 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 kind are components for ferroelectric materials.

Compounds of formula I with S _A phases are suitable for example for thermally addressed displays.

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

If R represents an alkyl radical in which two or more CH ₂ groups have been replaced by -O- and / or -CO-O-, this can be straight-chain or branched. It is preferably branched and has 3 to 12 carbon atoms. Accordingly, it means especially 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-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-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 (ethoxy carbonyl) - methyl, 2,2-bis (ethoxycarbonyl) ethyl, 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) butyl, 5,5-bis (ethoxycarbonyl) hexyl .

Compounds of the formula I which are used for polycondensation suitable wing groups R are suitable for display liquid-crystalline polycondensates.

Formula I includes both the racemates of these compounds also the optical antipodes and their mixtures.

Among these compounds of formula I and the sub formulas are preferred in which at least one of the residues contained therein is one of the preferred Has meanings.

In the compounds of formula I, those are stereo isomers preferred, in which the rings Cyc and piperidine are trans-1,4-disubstituted. Those of the above mentioned formulas, the one or more groups Pyd, Pyr and / or Dio included, each enclose the two 2,5-position isomers.

Some particularly preferred smaller groups of compounds are those of the sub-formulas I1 to I11:

The 1,4-cyclohexenylene group preferably has the following structures:

Some particularly preferred smaller groups of compounds are those of the sub-formulas IA to IE:

The compounds of formula I are known per se Methods presented as they are in the literature (e.g. in the Standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart Vol IX, pp. 867 ff.) are described, under reaction conditions that are known and suitable for the implementations mentioned.

It is also possible to do so from those known per se, but not here make use of the variants mentioned.

The compounds of the invention can e.g. B. prepared by using a compound of formula II,

wherein R, A ¹ , A ² , Z ¹ , Z ² and m have the meaning given, metalized according to the following reaction scheme and then reacted with a suitable electrophile:

Scheme 1

The target products are known from the phenol obtained ten methods, e.g. B. by reaction with 1,1-difluoroethane vaten in the presence of dioxane, sodium and DMF under pressure available.

Other synthetic methods are apparent to the expert. For example, correspondingly substituted 1,3-difluorobenzene compounds or monofluorinated analogues (L = H) can be converted into the 1,3-difluoro compounds or monofluorinated analogs (L = H) in the 5-position and the rest R- (A ¹ -Z ¹ ) _m -A ² -Z ² subsequently by reactions customary in liquid crystal chemistry (e.g. esterification, etherification or couplings e.g. according to the article E. Poetsch, contacts (Darmstadt) 1988 (2), p. 15).

The compounds of formula II can, for example, according to following synthesis schemes are prepared:

Scheme 2

(A = - (- A ¹ -Z ¹ ) _m - A ² - / Z ² = -CH ₂ CH ₂ -)

Scheme 3

(A = - (- A ¹ -Z ¹ -) _m - A ² - / Z ² = single bond)

Scheme 4

Scheme 5

Scheme 6

The starting materials are either known or can be found in Analogy to known compounds.  

Esters of the formula I can also correspond by esterification carboxylic acids (or their reactive derivatives) with alcohols or phenols (or their reactive Derivatives) or by the DCC method (DCC = dicyclohexyl carbodiimide) can be obtained.

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

The synthesis of some particularly preferred compounds is specified below:  

Scheme 7

Scheme 8

Esters of the formula I can also correspond by esterification carboxylic acids (or their reactive derivatives) with alcohols or phenols (or their reactive Derivatives) or by the DCC method (DCC = dicyclohexylcar bodiimid) can be obtained.  

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

In another process for making the compounds of the formula I, an aryl halide is reacted with an olefin in the presence of a tertiary amine and a palladium catalyst sators (see R.F. Heck, Acc. Chem. Res. 12 (1979) 146). Suitable aryl halides are, for example, chlorides, Bromides and iodides, especially bromides and iodides. The for the success of the coupling reaction required tertiary Amines such as B. triethylamine, are also suitable Solvent. Examples of palladium catalysts are its salts, especially Pd (II) acetate, with organic Phosphorus (III) compounds such as B. Triarylphosphanen suitable net. You can do this in the presence or absence of a inert solvent at temperatures between about 0 ° and 150 °, preferably between 20 ° and 100 °, work; as Solvents come e.g. B. nitriles such as acetonitrile or Hydrocarbons such as benzene or toluene into consideration. The Aryl halides and olefins used as starting materials are often commercially available or can be made according to litera be known processes, for example by halogenation of corresponding parent compounds or through elimination reactions on corresponding alcohols or halides.  

In this way, stilbene derivatives can be produced, for example bar. The stilbenes can still be made by Reaction of a 4-substituted benzaldehyde with a corresponding Phoshorylid after Wittig. But you can also Prepare tolanes of the formula I by instead of the oil monosubstituted acetylene (Synthesis 627 (1980) or Tetrahedron Lett. 27, 1171 (1986)).

Aryl halides can also be used to couple aromatics Aryltin compounds are implemented. These are preferred Reactions with the addition of a catalyst such. B. one Palladium (0) complex in inert solvents such as coal hydrogen at high temperatures, e.g. B. in boiling Xylene, carried out under protective gas.

Couplings of alkynyl compounds with aryl halides can be analogous to that of A.O. King, E. Negishi, F.J. Villani and A. Silveira in J. Org. Chem. 43, 358 (1978) Procedures are carried out.

Tolanes of the formula I can also be obtained via the Fritsch-Buttenberg Wiechell rearrangement (Ann. 279, 319, 1984) are produced, in which 1,1-diaryl-2-halogenethylenes are rearranged Diarylacetylenes in the presence of strong bases.

Tolanes of formula I can also be prepared by: the corresponding style level is brominated and then one Subjects to dehydrohalogenation. You can do it yourself well-known, not mentioned variants of this implementation apply the tongue.  

Ethers of the formula I can be obtained by etherification of corresponding hydroxyl compounds, preferably corresponding phenols, the hydroxyl compound advantageously first being converted into a corresponding metal derivative, e.g. B. by treatment with NaH, NaNH ₂ , NaOH, KOH, Na ₂ CO ₃ or K ₂ CO _{3 is converted} into the corresponding alkali metal alcoholate or alkali metal phenolate. This can then be reacted with the corresponding alkyl halide, sulfonate or dialkyl sulfate, who, advantageously in an inert solvent such as. As acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide or with an excess of aqueous or aqueous alcoholic shear NaOH or KOH at temperatures between about 20 ° and 100 °.

The starting materials are either known or can be found in Analogy to known compounds.

The compounds of the formula I 'with Z ² = - (CH ₂ ) ₄ - can be prepared according to the following scheme:

Scheme 9

In the Pd (II) -catalyzed coupling reaction, either directly the target product I 'or a preliminary product, in this is completely analogous to the above methods of connection gene or formula I the rest -Y is introduced.

The compounds of the formula I 'with Z ² = -CH = CH-CH ₂ CH ₂ - can also be prepared by Wittig according to the following scheme:

Scheme 10

The preferred trans isomers can according to the literature isomerization methods who manufactured the. Any preliminary products obtained with R ° = H become complete analogous to the precursors of the compounds of formula I. by introducing the radical -Y into the compounds of the formula I transferred.

The aldehydes can be reacted accordingly by Heck substituted 1-bromo-3-fluorobenzene derivatives with allyl alcohol can be obtained.

The liquid-crystalline media according to the invention contain preferably in addition to one or more of the invention Compounds as further components 2 to 40, in particular 4 to 30 components. Very particularly preferably included these media in addition to one or more of the invention Connections 7 to 25 components. This further inventory parts are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular their substances from the classes of azoxybenzenes, benzylidene anilines, biphenyls, terphenyls, phenyl or cyclohexylbenes zoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, Phenyl or cyclohexyl esters of cyclohexylbenzoic acid, Phenyl or cyclohexyl ester of cyclohexylcyclohexane bonic acid, cyclohexyl phenyl ester of benzoic acid, cyclo hexanecarboxylic acid, or cyclohexylcyclohexanecarboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcy clohexane, cyclohexylcyclohexane, cyclohexylcyclohexylcyclo hexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexyl biphenyls, phenyl or cyclohexyl pyrimidines, phenyl  or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, Phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclo hexyl-2- (4-phenyl-cyclohexyl) ethane, 1-cyclohexyl-2-bipheny lylethane, 1-phenyl-2-cyclohexyl-phenylethane, optionally halogenated stilbenes, benzylphenyl ether, tolanes and substi acted cinnamic acids. The 1,4-phenylene groups in these ver bonds can also be fluorinated.

The most important compounds which are suitable as further constituents of media according to the invention can be characterized by the formulas 1, 2, 3, 4 and 5:

R'-LE-R '' 1

R'-L-COO-E-R '' 2

R'-L-OOC-E-R '' 3

R'-L-CH ₂ CH ₂ -E-R "4

R'-L-C∼C-E-R '' 5.

In formulas 1, 2, 3, 4 and 5, L and E mean the same or can be different, each independently a bivalent residue from the from -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe- and -G-Cyc- as well whose mirror images formed group, whereby Phe unsubstituted ized or fluorine-substituted 1,4-phenylene, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexylene, Pyr Pyrimi din-2-5-diyl or pyridine-2,5-diyl, bio 1,3-dioxane2,5-diyl and G 2- (trans-1,4-cyclohexyl) ethyl, pyrimidine-2,5-diyl, Pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl mean.  

One of the radicals L and E is preferably Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. Preferably included ten the media according to the invention one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group Cyc, Phe and Pyr and simultaneously one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein one of L and E is selected from the group Cyc, Phe and Pyr and the other residue is selected from the Group -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally selected one or more components from the compounds of the formulas 1, 2, 3, 4 and 5, in which the Residues L and E are selected from the group -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.

R 'and R' 'mean in a smaller subset of the verb extensions of formulas 1, 2, 3, 4 and 5 each independently of each other alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or Alkanoyloxy with up to 8 carbon atoms. The following will this smaller subgroup is called Group A and the verb are with the sub-formulas 1a, 2a, 3a, 4a and 5a designated. Most of these compounds are R 'and R '' differ from one another, one of these residues mostly Is alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller subgroup, referred to as group B, of the compounds of the formulas 1, 2, 3, 4 and 5, R '' -F, -Cl, -NCS or - (O) _i CH _{3- (k + 1)} F _k Cl ₁ , where i is 0 or 1 and k + 1 is 1, 2 or 3; the compounds in which R ″ has this meaning are designated by the sub-formulas 1b, 2b, 3b, 4b and 5b. Those compounds of the sub-formulas 1b, 2b, 3b, 4b and 5b in which R ″ has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ are particularly preferred.

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b R 'the given for the compounds of sub-formulas 1a-5a Meaning and is preferably alkyl, alkenyl, alkoxy or Alkoxyalkyl.

In another smaller subset of the compounds of the Formulas 1, 2, 3, 4 and 5 mean R '' -CN; this subset is hereinafter referred to as group C and the connection This subgroup is created with sub-formulas 1c, 2c, 3c, 4c and 5c. In the connections of the R 'has partial formulas 1c, 2c, 3c, 4c and 5c for the verb and the meanings of the sub-formulas 1a-5a preferably alkyl, alkoxy or alkenyl.

In addition to the preferred compounds of groups A, B and C are also other compounds of the formulas 1, 2, 3, 4 and 5 with other variants of the proposed substituents in use. All of these substances are known from the literature methods or by analogy.

In addition to the compounds of the formula I according to the invention, the media according to the invention preferably contain one or more compounds which are selected from group A and / or group B and / or group C. The mass fractions of the compounds from these groups in the media according to the invention are preferred
Group A: 0 to 90%, preferably 20 to 90%, in particular 30 to 90%
Group B: 0 to 80%, preferably 10 to 80%, in particular 10 to 65%
Group C: 0 to 80%, preferably 5 to 80%, in particular 5 to 50%
wherein the sum of the mass fractions of the compounds from groups A and / or B and / or C contained in the respective media according to the invention is preferably 5% -90% and in particular 10% to 90%.

The media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30% of the invention appropriate connections. Media are also preferred holding more than 40%, in particular 45 to 90%, of inventions connections according to the invention. The media preferably contain three, four or five compounds according to the invention.

The media according to the invention are produced in yourself in the usual way. Usually the components dissolved in one another, expediently at elevated temperature. By The liquid-crystalline phases can be followed by suitable additives the invention can be modified so that it has been used in all known types of liquid crystal display elements can be used. Such additives are known to the person skilled in the art known and described in detail in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemistry, Weinheim, 1980). For example, pleochroiti  dyes for the production of colored guest-host systems or substances for changing the dielectric anisotrop pie, the viscosity and / or the orientation of the nematic Phases are added.

The following examples are intended to illustrate the invention without limiting it. Above and below, percentages mean weight percent. All temperatures are given in degrees Celsius. Mp. Means melting point, Kp. = Clearing point. Furthermore, K = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperatures. Δn means optical anisotropy (589 nm, 20 ° C) and the viscosity (mm ² / sec) was determined at 20 ° C.

"Conventional work-up" means: water is optionally added, extracted with methylene chloride, diethyl ether or toluene, separated, the organic phase is dried, evaporated and the product is purified by distillation under reduced pressure or crystallization and / or chromatography. The following abbreviations are used:
DAST: Diethylaminosulfur trifluoride
DCC: dicyclohexylcarbodiimide
DDQ. Dichlorodicyanobenzoquinone
DIBALH: diisobutyl aluminum hydride
Feces: Potassium tertiary butanolate
THF: tetrahydrofuran
pTSOH: p-toluenesulphonic acid
TMEDA: tetramethylethylenediamine

example 1

A mixture of 0.2 mol of 2,6-difluoro-4- [trans-4- (trans-4- Propylcyclohexyl) cyclohexyl] phenol (can be prepared according to the scheme 1), 80 ml of dioxane and 0.05 mol of sodium is at room temperature stirred for 2.5 hours. Then 40 ml of DMF are added and the Phenolatlsg. in an autoclave with 1,1-difluoro-2,2- dichlorethylene (2.7 bar) heated to 50-70 ° with stirring.

This process is repeated until the pressure is constant. Then the reaction mixture is mixed with water and as usual worked up. Obtained after cleaning by crystallization 2,6-difluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclo hexyl] -1,1-difluoro-2,2-dichloroethoxybenzene.

The following compounds of the formula become analogous

produced:

Examples 2 to 93

The following compounds of the formula according to the invention are obtained analogously from the corresponding precursors of the formula II:

Example 94

37.1 g of I (0.1 mol) in 150 ml of a solvent mixture of THF / toluene (1: 4 by volume ratio) are pre-charged, then 11.5 g of zinc bromide are anhydrous and 1.4 g of lithium granules are then added. The mixture is treated with ultrasound under argon and stirring for 4 hours between 0 ° C. and 10 ° C. in order to convert I into the corresponding dialkyl zinc compound. The organic zinc compound is mixed with 21.1 g of II (0.1 mol) and 1.5 g (2 mol%) of 1,1'-bis (diphenylphosphino) ferrocene-palladium (II) dichloride (PdCl ₂ dppf) and after removal of the ultrasonic bath and cooling, stirred for 24 hours at room temperature. It is decomposed with 100 ml of saturated NH ₄ Cl solution with stirring, the organic phase is separated off, the aqueous phase is extracted twice with toluene. The combined organic extracts provide after drying, concentration and chromatography on silica gel with hexane III. (I can be produced by chain extension using a malonic ester.) With II, the alkyl bromides listed below can be converted analogously to I:

Example 95

(r = 0.2 or 4)

According to the synthesis scheme above, after transfer of 1 into the organic zinc compound by a Pd (II) catalyst Coupled reaction obtained with 2, the compound 3. Hydrogenolytic cleavage of the benzyl ether leads to the phenol 4th

4.0 g (0.01 mol) of this phenol are analogous to Example 1 implemented further and the obtained 5 recrystallized from ethanol siert.

The following compounds of the formula become analogous

receive:

Claims (5)

1. benzene derivatives of the formula I,
wherein
RH, an unsubstituted, a simply by CN or CF ₃ or an at least one halogen-substituted alkyl or alkenyl radical having 1 to 15 carbon atoms, in which radicals one or more CH ₂ groups are each independently of one another -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- can be replaced so that O atoms are not directly linked to each other,
L ¹ and L ² each independently of one another H, F or Cl A ¹ and A ² each independently of one another

• (a) trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH ₂ groups can also be replaced by -O- and / or -S-,
• (b) 1,4-phenylene radical, in which one or two CH groups can also be replaced by N,
• (c) radical from the group 1,4-cyclohexenylene, 1,4-bicyclo (2,2,2) -octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydro-naphthalene-2,6 -diyl and 1,2,3,4-tetra hydronaphthalene-2,6-diyl,

where the radicals (a) and (b) can be substituted by one or two fluorine,
Z ¹ and Z ² each independently of one another -CO-O-, -O-CO-, -CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ -, -CH = CH-, -C∼C- or a single bond, one of the radicals Z ¹ and Z ² also - (CH ₂ ) ₄ - or -CH = CH- CH ₂ CH ₂ -,
m 0, 1 or 2,
X ¹ F or Cl, and
X ² Cl, CF ₃ , OCF ₃ or OCHF ₂
means. 2. Use of compounds of formula I according to claim 1 as Components of liquid crystalline media. 3. Use of compounds of formula I according to claim 1 in one liquid crystalline medium containing at least two liquid crystalline Components. 4. Use of compounds of formula I according to claim 1 in one Liquid crystal display element. 5. Use of compounds of formula I according to claim 1 as Dielectric in an electro-optical display element.