DE4218976B4 - benzene derivatives - Google Patents

Abstract

worin
R¹ H, einen unsubstituierten, einen einfach durch CN oder CF₃ oder einen mindestens einfach durch Halogen substituierten Alkyl- oder Alkenylrest mit 1 bis 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH₂-Gruppen jeweils unabhängig voneinander durch -O-, -S-,

-CO-, -CO-O-, -O-CO- oder -O-CO-O- so ersetzt sein können, daß O-Atome nicht direkt miteinander verknüpft sind,
R² einen unsubstituierten oder einen mindestens einfach durch Halogen substituierten Alkyl- oder Alkenylrest mit 1 bis 15 C-Atomen,
A¹ und A² jeweils unabhängig voneinander einen
(a) trans-1,4-Cyclohexylenrest, worin auch eine oder mehrere nicht benachbarte CH₂-Gruppen durch -O- und/oder -S- ersetzt sein können,
(b) 1,4-Phenylenrest, worin auch eine oder zwei CH-Gruppen durch N ersetzt sein können,
(c) Rest aus der Gruppe 1,4-Cyclohexenylen, 1,4-Bicyclo(2,2,2)-octylen, Piperidin-1,4-diyl, Naphthalin-2,6-diyl, Decahydronaphthalin-2,6-diyl und 1,2,3,4-Tetrahydronaphthalin-2,6-diyl,
wobei die Reste (a) und (b) durch CN oder Fluor substituiert sein können,...Benzene derivatives of the formula I,

wherein
R ^{1 is} H, an unsubstituted, an alkyl or alkenyl radical having 1 to 15 C atoms which is monosubstituted by CN or CF ₃ or at least monosubstituted by halogen, where one or more CH ₂ groups in these radicals are also each independently O-, -S-,

-CO-, -CO-O-, -O-CO- or -O-CO-O- may be replaced so that O atoms are not directly linked to one another,
R ^{2 is} an unsubstituted or at least monosubstituted by halogen alkyl or alkenyl radical having 1 to 15 carbon atoms,
A ¹ and A ² each independently
(a) trans-1,4-cyclohexylene radical, in which also one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S-,
(b) 1,4-phenylene radical, in which also one or two CH groups may be replaced by N,
(c) radical from the group consisting of 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 radicals (a) and (b) can be substituted by CN or fluorine,

Description

worin
R¹ H, einen unsubstituierten, einen einfach durch CN oder CF₃ oder einen mindestens einfach durch Halogen substituierten Alkyl- oder Alkenylrest mit 1 bis 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH₂-Gruppen jeweils unabhängig voneinander durch -O-, -S-,

-CO-, -CO-O-, -O-CO- oder -O-CO-O- so ersetzt sein können, daß O-Atome nicht direkt miteinander verknüpft sind,
R² einen unsubstituierten oder einen mindestens einfach durch Halogen substituierten Alkyl- oder Alkenylrest mit 1 bis 15 C-Atomen,
A¹ und A² jeweils unabhängig voneinander einen

• (a) trans-1,4-Cyclohexylenrest, worin auch eine oder mehrere nicht benachbarte CH₂-Gruppen durch -O- und/oder -S- ersetzt sein können,
• (b) 1,4-Phenylenrest, worin auch eine oder zwei CH-Gruppen durch N ersetzt sein können,
• (c) Rest aus der Gruppe 1,4-Cyclohexenylen, 1,4-Bicyclo(2,2,2)-octylen, Piperidin-1,4-diyl, Naphthalin-2,6-diyl, Decahydronaphthalin-2,6-diyl und 1,2,3,4-Tetrahydronaphthalin-2,6-diyl,

wobei die Reste (a) und (b) durch CN oder Fluor substituiert sein können,
Z¹, Z² und Z³ jeweils unabhängig voneinander -CO-O-, -O-CO-, -CH₂O-, -OCH₂-, -CH₂CH₂-, -CH=CH-, -C≡C- oder eine Einfachbindung, einer der Reste Z¹ und Z² auch -(CH₂)₄- oder -CH=CH-CH₂CH₂-,
L^1-4 H oder F, wobei mindestens einer der Reste L^1-4 F bedeutet,
m 0, 1 oder 2
n 0 oder 1, und
r 1 bis 7
bedeutet, sowie diese enthaltende flüssigkristalline Medien.The invention relates to benzene derivatives of the formula I,

wherein
R ^{1 is} H, an unsubstituted, an alkyl or alkenyl radical having 1 to 15 C atoms which is monosubstituted by CN or CF ₃ or at least monosubstituted by halogen, where one or more CH ₂ groups in these radicals are also each independently O-, -S-,

-CO-, -CO-O-, -O-CO- or -O-CO-O- may be replaced so that O atoms are not directly linked to one another,
R ^{2 is} an unsubstituted or at least monosubstituted by halogen alkyl or alkenyl radical having 1 to 15 carbon atoms,
A ¹ and A ² each independently

• (a) trans-1,4-cyclohexylene radical, in which also one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S-,
• (b) 1,4-phenylene radical, in which also one or two CH groups may be replaced by N,
• (c) radical from the group consisting of 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 radicals (a) and (b) may be substituted by CN or fluorine,
Z ¹ , Z ² and Z ^{3 are} each independently -CO-O-, -O-CO-, -CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ -, -CH = CH-, -C≡ C or a single bond, one of Z ¹ and Z ² also - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ -,
L ^1-4 H or F, where at least one of the radicals L ^{1-4 is} F,
m 0, 1 or 2
n 0 or 1, and
r 1 to 7
means, as well as these containing liquid-crystalline media.

The Compounds of the formula I can as components of liquid crystalline Media are used, especially for displays based on the principle the twisted cell, the guest-host effect, the effect of deforming upright phases or the effect based on dynamic dispersion.

Of the Invention was based on the object new stable liquid crystalline or to find mesogenic compounds which are components of liquid-crystalline Media are suitable and in particular at the same time a comparatively low viscosity have a relatively high dielectric anisotropy and a high nematogeneity.

It has now been found that compounds of the formula I as components of liquid-crystalline Media excellent are suitable. In TN and STN cells, the compounds of the invention effect a large surface angle, which leads to improved electro-optical properties. Especially feature she over comparatively low viscosities and high nematogeneities. With their help is stable with liquid crystalline media broad mesophase range and favorable values for the optical and dielectric anisotropy. These media also have a very good low temperature behavior, i. excellent solubility in the usual FK materials, at the same time the occurrence of smectic Phases effectively suppressed becomes.

sind bereits aus der EP 0 385 471 bekannt.Liquid crystals of the formulas

are already out of the EP 0 385 471 known.

in the With regard to the most diverse fields of application of such compounds however, it was desirable more connections available to have tailor-made to the particular applications Have properties.

With the provision of compounds of the formula I is also complete in general, the range of liquid crystalline Substances that differ from different application-technical points of view for the production of liquid crystalline Mixtures are suitable, considerably widened.

The Compounds of the formula I have a wide range of applications. Dependent on from the choice of substituents, these compounds can be considered as Base materials serve, from which liquid-crystalline media for the predominant Part are composed; it can but also compounds of the formula I liquid-crystalline base materials be added from other classes of compounds, for example the dielectric and / or optical anisotropy of such a dielectric to influence and / or its threshold voltage and / or its viscosity to optimize.

The Compounds of the formula I are colorless in the pure state and form liquid crystalline Mesophases in a for the electro-optical use favorable located temperature range. Chemical, thermal and against light they are stable.

object The invention thus relates to the compounds of the formula I and the Use of these compounds as components of liquid-crystalline Media. The invention further liquid-crystalline media with a content of at least one compound of the formula I.

und A³

Cyc eine 1,4-Cyclohexylenrest,
Che einen 1,4-Cyclohexenylenrest, Dio einen 1,3-Dioxan-2,5-diylrest, Dit einen 1,3-Dithian-2,5-diylrest, Phe einen 1,4-Phenylenrest, Pyd einen Pyridin-2,5-diylrest, Pyr einen Pyrimidin-2,5-diylrest und Bi einen Bicyclo(2,2,2)-octylenrest, wobei Cyc und/oder Phe unsubstituiert oder ein- oder zweifach durch F oder CN substituiert sein können. Y ist -O-(C₂H₄O)_r-R².For the sake of simplicity, A ⁴ in the following mean a radical of the formula

and A ³

Cyc is a 1,4-cyclohexylene radical,
Che is a 1,4-cyclohexenylene radical, Dio is a 1,3-dioxane-2,5-diyl radical, Dit is a 1,3-dithiane-2,5-diyl radical, Phe is a 1,4-phenylene radical, Pyd is a pyridine-2, 5-diyl radical, Pyr is a pyrimidine-2,5-diyl radical and Bi is a bicyclo (2,2,2) -octylene radical, where Cyc and / or Phe can be unsubstituted or monosubstituted or disubstituted by F or CN. Y is -O- (C ₂ H ₄ O) _r -R ² .

The compounds of formula I accordingly comprise compounds having two rings of the part Formula Ia: R ¹ -A ² -Z ² -A ⁴ -Y Ia

Compounds with three rings of sub-formulas Ib and Ic: R ¹ -A ¹ -Z ¹ -A ² -Z ² -A ⁴ -Y Ib R ¹ -A ² -Z ² -A ³ -Z ³ -A ⁴ -Y IC

Compounds with four rings of partial formulas Id and Ie: R ¹ -A ¹ -Z ¹ -A ² -Z ² -A ³ -Z ³ -A ⁴ -Y Id R ¹ -A ¹ -Z ¹ -A ¹ -Z ¹ -A ² -Z ² -A ⁴ -Y Ie and five-membered compounds of partial formula If R ¹ -A ¹ -Z ¹ -A ¹ -Z ¹ -A ² -Z ² -A ³ -Z ³ -A ⁴ -Y If ,

The preferred compounds of the partial formula Ia include those of the partial formulas Iaa to Iag R ¹ -Phe-Z ² -A ⁴ -Y Iaa R ¹ -Cyc-Z ² -A ⁴ -Y Iab R ¹ -Pyr-Z ² -A ⁴ -Y Iac R ¹ -pyd-Z ² -A ⁴ -Y Iad R ¹ -Che-Z ² -A ⁴ -Y Iae R ¹ -Dio-Z ² -A ⁴ -Y Iaf R ¹ -Dit-Z ² -A ⁴ -Y tag

among them those of the formulas Iaa, Iab and Iac are particularly preferred.

The preferred compounds of sub-formula Ib include those of sub-formulas Iba to Ibk R ¹ -Phe-Z ¹ -Phe-Z ² -A ⁴ -Y Iba R ¹ -Cyc-Z ¹ -Phe-22-A ⁴ -Y Ibb R ¹ -Dio-Z ¹ -Phe-Z ² -A ⁴ -Y Ibc R ¹ -Che-Z ¹ -Phe-Z ² -A ⁴ -Y Iba R ¹ -Pyd-Z ¹ -Phe-Z ² -A ⁴ -Y Ibe R ¹ -Pyr-Z ¹ -Phe-Z ² -A ⁴ -Y Ibf R ¹ -Cyc-Z ¹ -Cyc-Z ² -A ⁴ -Y Ibf R ¹ -Cyc-Z ¹ -Cyc-Z ² -A ⁴ -Y Ib R ¹ -Phe-Z ¹ -Cyc-Z ² -A ⁴ -Y Ibh R ¹ -Cyc-Z ¹ -Pyr-Z ² -A ⁴ -Y Ibi R ¹ -Phe-Z ¹ -Pyr-Z ² -A ⁴ -Y Ibj R ¹ -CyC-CyC-CH ₂ CH ₂ -A ⁴ -Y Ibk

among them are those of the subformulae Iba, Ibb, Ibf, Ibg, Ibh and Ibk prefers.

The preferred compounds of sub-formula Ic include those of sub-examples Ica to Icg R ¹ -Phe-Z ² -A ³ -Z ³ -A ⁴ -Y Ica R ¹ -Cyc-Z ² -A ³ -Z ³ -A ⁴ -Y Icb R ¹ -Che-Z ² -A ³ -Z ³ -A ⁴ -Y Icc R ¹ -Dio-Z ² -A ³ -Z ³ -A ⁴ -Y Icd R ¹ -Che-Z ² -A ³ -Z ³ -A ⁴ -Y Ice R ¹ -Pyr-Z ² -A ³ -Z ³ -A ⁴ -Y Icf R ¹ -Pyd-Z ² -A ³ -Z ³ -A ⁴ -Y Icg

among them those of the formulas Ica, Icb and Icg are particularly preferred.

The preferred compounds of the partial formula Id include those of the partial formulas Ida to Idl R ¹ -Phe-Z ¹ -Phe-Z ² -A ³ -Z ³ -A ⁴ -Y Ida R ¹ -Pyr-Z ¹ -Phe-Z ² -A ³ -Z ³ -A ⁴ -Y Idb R ¹ -Cyc-Z ¹ -Phe-Z ² -A ³ -Z ³ -A ⁴ -Y Idc R ¹ -Cyc-Z ¹ -Cyc-Z ² -A ³ -Z ³ -A ⁴ -Y Idd R ¹ -Cyc-CY-CH ₂ CH ₂ -A ³ -Z ³ -A ⁴ -Y Ide R ¹ -Phe-Phe-OOC-A ³ -Z ³ -A ⁴ -Y Idf R ¹ -Pyd-Z ¹ -Phe-A ³ -Z ³ -A ⁴ -Y Idg R ¹ -Dio-Z ¹ -Phe-A ³ -Z ³ -A ⁴ -Y Idh R ¹ -Phe-Z ¹ -Cyc-A ³ -Z ³ -A ⁴ -Y Idi R ¹ -Phe-Z ¹ -Pyr-A ³ -Z ³ -A ⁴ -Y Idj R ¹ -Che-Z ¹ -PheA ³ -Z ³ -A ⁴ -Y Idk R ¹ -Cyc-Phe-OOC-A ³ -Z ³ -A ⁴ -Y Idl

among them those of the formulas Ida, Idc, Idd, Ide and Idi are especially special prefers.

The preferred compounds of sub-formula Ie include those of sub-formulas Iea to IEC R ¹ -Phe-Z ¹ -Phe-Z ¹ -Phe-Z ² -A ³ -A ⁴ -Y Iea R ¹ -Phe-Z ¹ -Phe-Z ¹ -Cyc-Z ² -A ³ -A ⁴ -Y Ieb R ¹ -Cyc-Phe-A ³ -A ⁴ -Y Iec R ¹ 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.

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

Preference is also given to compounds of the formula I and of all subformulae in which A ¹ and / or A ^{2 is} monosubstituted or disubstituted by F or simply by CN-substituted 1,4-phenylene. 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.

Z ¹ , Z ² and Z ^{3 are} preferably a single bond, -CO-O-, -O-CO- and -CH ₂ CH ₂ -, secondarily preferably -CH ₂ O- and -OCH ₂ -.

oder

-A³-Z³-A⁴ bedeutet vorzugsweise

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.
m is preferably 0 or 1 and r is preferably 1.
A ⁴ is preferred

or

-A ³ -Z ³ -A ⁴ is preferably

worin Z² eine Einfachbindung, -C₂H₄-, -(CH₂)₄-, -C≡C- oder -CH=CH-CHZCH2- bedeutet und R¹, R², A¹, A², Z¹, L⁴ und m die in Formel I angegebene Bedeutung haben.Preferred compounds of the formula I correspond to the partial formula I ',

wherein Z ^{2 is} a single bond, -C ₂ H ₄ -, - (CH ₂ ) ₄ -, -C≡C- or -CH = CH-CHZCH ₂ - and R ¹ , R ² , A ¹ , A ² , Z ¹ , L ⁴ and m have the meaning given in formula I.

If R ¹ and R ² denote an alkyl radical and / or an alkoxy radical, these may be straight-chain or branched. Preferably, they are straight-chain, have 2, 3, 4, 5, 6 or 7 carbon atoms and therefore preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl , Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

oxaalkyl preferably denotes 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-oxo-octyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R ¹ and R ^{2 are} alkenyl radicals, these may be straight-chain or branched. Preferably, they are straight-chain and have 2 to 10 carbon atoms. Accordingly, they mean in particular 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-S-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.

If R ^{1 is} an alkyl radical in which one CH ₂ group is replaced by -O- and one by -CO-, these are preferably adjacent. Thus, they include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. Preferably, these are straight-chain and have 2 to 6 carbon atoms.

she therefore especially acetyloxy, propionyloxy, butyryloxy, Pentanoyloxy, hexanoxyloxy, acetyloxymethyl, propionyloxymethyl, Butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-actyloxybutyl, Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbanyl, Pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, Butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) -butyl.

If R ^{1 is} an alkenyl radical in which one of the vinyl group adjacent CH ₂ group is replaced by CO or CO-O or O-CO-, this may be straight-chain or branched. Preferably, it is straight-chain and has 4 to 13 carbon atoms. It therefore particularly means acryloyloxymethyl, 2-acryloxyloxyethyl, 3-acryloyloxypropyl, 9-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 3 Methacryloyloxypropyl, 4-methacryloyloxy-butyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl, 9-methacryloyloxynonyl.

If R ¹ is a monosubstituted by CN or CF ₃ alkyl or alkenyl radical, this radical is preferably straight-chain and the substitution by CN or CF ₃ in ω-position.

If R ^{1 is} an alkyl or alkenyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain and halogen is preferably F or Cl. In the case of multiple substitution, halogen is preferably F. The resulting radicals also include perfluorinated radicals. In the case of single substitution, the fluorine or chlorine substituent may be in any position, but preferably in the ω position.

Compounds of the formula I which have wing groups R ¹ suitable for polymerization reactions are suitable for the preparation of liquid-crystalline polymers.

Compounds of the formulas I with branched wing groups R ¹ may occasionally be of importance for better solubility in the customary liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Smectic compounds of this type are useful as components of ferroelectric materials. Compounds of the formula I with S _A phases are suitable, for example, for thermally addressed displays.

branched Groups of this kind usually contain no more than one chain branch. Preferred branched radicals R 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.

If R ^{1 represents} an alkyl radical in which two or more CH ₂ groups have been replaced by -O- and / or -CO-O-, this may be straight-chain or branched. Preferably, it is branched and has 3 to 12 carbon atoms. It therefore particularly denotes 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 (methoxycarbo nyl) octyl, bis (ethoxycarbonyl) methyl, 2,2-bis (ethoxycarbonyl) ethyl, 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) -butyl, 5 , 5-bis- (ethoxycarbonyl) -hexyl.

Under these compounds of the formula I and the sub-formulas are those preferred in which at least one of the radicals contained therein has one of the preferred meanings given.

Some very particularly preferred smaller groups of compounds are those of the subformulae I1 to I17:

The Compounds of the formula I are prepared by methods known per se as described in the literature (e.g., in the standard works as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart Bd. IX, p. 867 ff.) Are described, under reaction conditions, the for the said reactions are known and suitable.

there You can also from known, not mentioned here variants Make use.

worin R¹, R², A¹, A², Z¹, Z², Z³, L¹, L², L³, L⁴, m und n die in Anspruch 1 angegebene Bedeutung haben, gemäß folgendem Reaktionsschema metalliert und anschließend mit einem geeigneten Elektrophil umsetzt: Schema 1

The compounds of the formula I according to the invention can be prepared, for example, by reacting a compound of the formula II,

wherein R ¹ , R ² , A ¹ , A ² , Z ¹ , Z ² , Z ³ , L ¹ , L ² , L ³ , L ⁴ , m and n have the meaning given in claim 1, metallated according to the following reaction scheme and then reacted with a suitable electrophile: Scheme 1

Out the resulting phenol derivative of formula III are the compounds of the formula I according to known etherification methods available.

anschließend durch in der Flüssigkristallchemie gebräuchliche Reaktionen (z.B. Veretherung oder Kopplungen z.B. gemäß dem Artikel E. Poetsch, Kontakte (Darmstadt) 1988 (2), S. 15) eingeführt werden.Other synthetic methods will be apparent to those skilled in the art. For example, in the 5-position, appropriately substituted 1,3-difluorobenzene compounds or monofluorinated analogs (L ⁴ = H) according to above scheme are converted to the 2-OC ₂ H ₄ -OR ² -1,3-difluoro compounds or monofluorinated analogs (L ⁴ = H) and the remainder

subsequently by reactions customary in liquid-crystal chemistry (for example etherification or couplings, for example, according to the article E. Poetsch, Contacts (Darmstadt) 1988 (2), p. 15).

The compounds of the formula II (n = 0) can be prepared, for example, according to the following synthesis scheme:

The dioxalalkyl compounds can be prepared, for example, according to Mitsunobu from the corresponding phenols III and a hydroxy compound in the presence of triphenylphosphine and diethyl azodicarboxylate (S. Bittner, Y. Assaf, Chemistry and Industry, 281 (1975) MS Manhas, WH Hoffman, B. Lal, AK Bose, J. Chem. Soc. Perkin I, 461 11975)): Scheme 3

Furthermore, the compounds of the formula I are obtainable, for example, by etherification of corresponding hydroxy compounds, preferably corresponding phenols, where the hydroxy compound is first expediently converted into a corresponding metal derivative, for example 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, suitably in an inert solvent such as acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide or with an excess of aqueous or aqueous-alkanolic NaOH or KOH at temperatures between about 20 ° and 100 ° C.

The synthesis of some particularly preferred compounds is described in more detail below

The Starting materials for the manufacturing processes are either known or can be found in Be prepared analogously to known compounds.

The compounds of formula I "with Z ² = - (CH ₂ ) ₄ - can be prepared according to the following scheme: Scheme 5

In the Pd (II) -catalyzed coupling reaction either directly the target product I '' is formed or a precursor into which the radical -OC ₂ H ₄ -OR ^{2 is} introduced completely analogously to the above methods for compounds of the formula I.

The liquid crystalline according to the invention Media preferably contain one or more compounds of the invention as further constituents 2 to 40, in particular 4 to 30 components. All more preferably, these media contain one or more besides Compounds of the invention ? up to 25 components. These other ingredients are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, especially substances from the classes of the azoxybenzenes, Benzylidenaniline, Biphenyls, terphenyls, phenyl or cyclohexyl benzoates, cyclohexane-carboxylic acid-phenyl or cyclohexyl esters, phenyl or cyclohexyl esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, cyclohexyl-phenylester the benzoic acid, the cyclohexane carboxylic acid, or cyclohexylcyclohexanecarboxylic acid, phenylcyclohexanes, cyclohexylbiphenyls, Phenylcyclohexylcyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-biscyclohexylbenzenes, 4,4'-biscyclohexylbiphenyls, Phenyl or cyclohexylpyrimidines, phenyl or cyclohexylpyridines, Phenyl or cyclohexyldioxanes, phenyl or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4-phenyl-cyclohexyl) -ethanes, 1-Cyclohexyl-2-biphenylylethanes, 1-phenyl-2-cyclohexyl-phenylethanes, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substituted cinnamic acids. The 1,4-phenylene groups in these compounds can also be fluorinated.

The most important compounds which may be used 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'-LC≡-E-R "5

In the formulas 1, 2, 3, 4 and 5, L and E, the same or different could be, each independently each other is a bivalent radical from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc, -Cyc-Cyc, -Pyr-, -Dio, -G-Phe- and -G-Cyc- and their Mirror images formed group, with Phe unsubstituted or fluorine-substituted 1,4-phenylene, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexylene, pyr pyrimidine-2-5-diyl or pyridine-2,5-diyl, Bio 1,3-dioxane-2,5-diyl and G 2- (trans-1,4-cyclohexyl) -ethyl, pyrimidine-2,5-diyl, Pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl.

Preferably is one of the radicals L and E is Cyc, Phe or Pyr. E is preferred Cyc, Phe or Phe-Cyc. Preferably, the media of the invention contain one or more components selected from the compounds of Formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group Cyc, Phe and Pyr and at the same time one or more components selected from the compounds of formulas 1, 2, 3, 4 and 5, wherein one of the radicals L and E selected is selected from the group Cyc, Phe and Pyr and the other radical is selected from the group -Phe-Phe, -Phe-Cyc, -Cyc-Cyc, -G-Phe and -G-Cyc-, and optionally one or more components selected from the compounds of formulas 1, 2, 3, 4 and 5, wherein the radicals L and E selected are from the group -Phe-Cyc, -Cyc-Cyc, -G-Phe and -G-Cyc-.

R 'and R' 'are in a smaller subgroup the compounds of formulas 1, 2, 3, 4 and 5 are each independently Alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. Below is this smaller one Subgroup group A called and the compounds are with the Partial formulas 1a, 2a, 3a, 4a and 5a. For most of these Compounds are R 'and R '' different from each other, wherein one of these radicals is usually alkyl, alkenyl, alkoxy or alkoxyalkyl is.

In a smaller subgroup of compounds of formulas 1, 2, 3, 4 and 5, other than group B, R '' is -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 subformulae 1b, 2b, 3b, 4b and 5b. Particular preference is given to those compounds of the subformulae 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ .

In R 'has the compounds of the sub-formulas 1b, 2b, 3b, 4b and 5b in the compounds of sub-formulas 1a-5a and is preferably Alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 are R "-CN; this subgroup is hereinafter referred to as group C and the compounds of this Subgroup corresponding to sub-formulas 1c, 2c, 3c, 4c and 5 c described. In the compounds of sub-formulas 1c, 2c, 3c, 4c and 5c has R 'the in the compounds of the sub-formulas 1a-5a meaning indicated and is preferably alkyl, alkoxy or alkenyl.

Next the preferred compounds of groups A, B and C are also others Compounds of formulas 1, 2, 3, 4 and 5 with other variants the proposed substituents in use. All these substances are available by literature methods or in analogy thereto.

In addition to compounds of the formula I according to the invention, the media according to the invention preferably comprise one or more compounds which are selected from the group A and / or group B and / or group C. The mass fractions of the compounds from these groups on 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%, especially 10 to 65% Group C: 0 to 80%, preferably 5 to 80%, especially 5 to 50% wherein the sum of the mass fractions of Verbin contained in the respective media according to the invention groups from the groups A and / or 8 and / or C is preferably 5% -90% and in particular 10% to 90%.

The inventive media preferably contain 1 to 40%, especially preferably 5 to 30 % of compounds of the invention. Further preferred are media containing more than 40%, in particular 45 to 90% of compounds of the invention. The media preferably contain three, four or five compounds according to the invention.

The Production of the media according to the invention takes place in per se usual Wise. In general, the components are dissolved in each other, useful in increased Temperature. By suitable additives can they liquid crystalline Phases according to the invention are modified so that they are in all types of liquid crystal display elements known so far can be used. Such additives are known in the art and described in detail in the literature (H.Kalkker / R.Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, pleochroic dyes for the production of colored guest host systems or substances for change dielectric anisotropy, viscosity and / or orientation be added to the nematic phases.

The following examples are intended to illustrate the invention without limiting it. "Working up" means adding water, extracting with dichloromethane, separating, drying the organic phase, evaporating and purifying the product by crystallization and / or chromatography. Above and below mean percentages by weight. All temperatures are in degrees Celsius. Mp. Means melting point and 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). The viscosity (mm ² / sec) was determined at 20 ° C.

BuLi

Butyllithium

THF

Tetrahydrofuran

TMEDA

Tetramethylethylendiamin

DCC

Dicyclohexylcarbodiimid

DMRP

2-Dimethylaminopyridin

DEAD

Diethylazodicarboxylat

NMP

1-Methyl-2-pyrrolidon

The following abbreviations are used:

BuLi

butyllithium

THF

tetrahydrofuran

TMEDA

tetramethylethylenediamine

DCC

dicyclohexylcarbodiimide

DMRP

2-dimethylaminopyridine

DEAD

diethyl

NMP

1-methyl-2-pyrrolidone

example 1

• a)
  
  To 1.1 moles of magnesium turnings in 200 ml of THF are added two drops of bromine. Subsequently, under inert gas, a solution consisting of 1.1 mol of 3,5-difluorobromobenzene and 250 ml of THF is added dropwise so that the mixture boils at reflux. After completion of the addition, it is refluxed for 1.5 hours. 1.0 mmol of 4-n-propylcyclohexanone, dissolved in 500 ml of THF, is then added dropwise in the course of 45 minutes at the boiling point. Thereafter, a further hour is refluxed. The mixture is allowed to cool to room temperature and hydrolyzed under ice cooling with half konz. HCl. The organic solution is separated and worked up as usual.
• b)
  
  0.82 mol of 1,3-difluoro-trans-4-n-propylcyclohexyl) benzene are dissolved in 1500 ml of THF and admixed with 1.63 mol of potassium tert-butoxide in 750 ml of NMP in portions at 15-17 ° C. The mixture is then stirred for 1 h at this temperature. The mixture is poured into 2 l of ice-water and 150 ml of conc. HCl stirred. It is then extracted with tert-butyl methyl ether and worked up as usual.
• c)
  
  0.08 mol of 1,3-difluoro-trans- (4-n-propylcyclohexyl) benzene are dissolved in 250 ml of THF and treated at -70 ° C with 52 ml of BuLi in portions. The mixture is then stirred for 4 h at this temperature. After addition of 0.094 mol of trimethyl borate is stirred for a further hour at -70 ° C. It is allowed to warm to -30 ° C and added dropwise 17 ml of glacial acetic acid to the solution. Then allowed to stir overnight at room temperature and then dripping 22 ml of a 30% H ₂ O ₂ solution to the mixture. It is then boiled for 2 h at reflux. It is allowed to cool, mixed with water and extracted with tert-butyl methyl ether. Thereafter, the organic phase is worked up as usual.
• d)
  
  A mixture consisting of 0.16 mol of 2,6-difluoro-trans- (4-n-propylcyclohexyl) phenol, 0.179 mol of potassium carbonate, 400 ml of methyl ethyl ketone and 0.179 mol of (2-bromoethyl) methyl ether are refluxed under inert gas for 24 h , It is allowed to cool, mixed with water and worked up as usual. K-9II, Δ∈ = -1.95, Δn = + 0.023

hergestellt:

Analogously, the following compounds of the formula

produced:

Example 2

• a)
  
  78 mmol of potassium tert-butoxide are dissolved at -5 ° C. in 78 mmol of 1- (4- (4-n-pentylcyclohexyl) cyclohexyl) methylenetriphenylphosphonium iodide and 78 mmol of 3,5-difluorobenzaldehyde dissolved in 50 ml of THF 80 ml of THF was added dropwise. The mixture is then stirred at the same temperature for 15 minutes and a further 1.5 h at room temperature. The reaction mixture is hydrolyzed and neutralized with hydrochloric acid. Then it is worked up as usual.
• b)
  
  Analogously to Example 1c and d), the product prepared in Example 2 a) is converted into the phenol compound and then reacted with (2-bromoethyl) methyl ether.

Analogously, the following compounds of the formula are obtained

Example 3

• a)
  
  9 mmol of product from Example 2 a) are dissolved in 30 ml of THF, treated with 0.3 g of 4% Pd-C and hydrogenated. Then, the catalyst is filtered off and the filtrate is concentrated in vacuo to the residue. This is chromatographed on a silica gel column with pentane.
• b)
  
  Analogously to Example 2 b), the product obtained in Example 3 a) is first reacted with trimethyl borate and H ₂ O ₂ / acetic acid and then with (2-bromoethyl) methyl ether.

Analogously, the following compounds of the formula are obtained

Example 4

• a)
  
  0.1 mol of 4- (4-n-pentylcyclohexyl) - (cyclohexylbutylbromid) are initially charged in 150 ml of a solvent mixture of THF / toluene (1: 4), then 11.5 g of zinc bromide anhydrous and then added to 1.4 g of lithium granules. The mixture is sonicated under argon with stirring for 4 hours between 0 ° C and 10 ° C. The resulting organozinc compound is mixed with 0.1 mol of 3,5-difluoro-1-bromo-benzene and 2 mol% of 1,1'-bis (diphenylphosphino) ferrocene-palladium (II) dichloride and after removal of the ultrasonic bath and Cooling for 24 h at room temperature. It is decomposed with 100 ml of saturated NH ₄ Cl solution with stirring, the organic phase separated, the aqueous phase extracted with toluene. The combined organic extracts are dried, concentrated and chromatographed on silica gel.
• b)
  
  The reaction of the difluorobenzene with BuLi and trimethyl borate to form difluorophenol is carried out analogously to Example 1 c).
• c)
  
  Analogously to Example 2 b), the difluorophenol from Example 4 b) is converted to Dioxaalkylverbindung.

Analogously, the following compounds of the formula according to the invention are obtained

Claims (4)

Benzene derivatives of the formula I,

wherein R ^{1 is} H, an unsubstituted, an alkyl or alkenyl radical having 1 to 15 carbon atoms, which is monosubstituted by CN or CF ₃ or at least monosubstituted by halogen, wherein one or more CH ₂ groups in these radicals 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 together, R ^{2 is} an unsubstituted or at least one halogen-substituted alkyl or alkenyl radical having 1 to 15 C atoms, A ¹ and A ^{2 in} each case independently of one another represent a (a) trans-1,4-cyclohexylene radical in which one or more non-adjacent CH ₂ groups is also substituted by -O- and / or - (B) 1,4-phenylene radical, in which also one or two CH groups may be replaced by N, (c) radical from the group consisting of 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, wherein the radicals (a) and (b) may be substituted by CN or fluorine, Z ¹ , Z ² and Z ^{3 are} each independently -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 , Z ² and Z ³ also - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ -, L ^1-4 H or F, wherein at least one of the radicals L ^{1-4 is} F, m is 0, 1 or 2 n is 0 or 1, and r is 1 to 7. Compounds of the formula

wherein R ¹ , R ² , Z ¹ , L ³ and L ⁴ , have the meaning given in claim 1. Compounds of the formula

wherein R ¹ , R ² , L ² , L ³ and L ^{4 have} the meaning given in claim 1. liquid-crystalline Medium with at least two liquid-crystalline Components, characterized in that there is at least one compound of the formula I contains.