WO1993003113A1 - Liquid-crystal compounds - Google Patents

Abstract

Disclosed are liquid-crystal compounds of formula (I), in which R is H, an unsubstituted alkyl or alkenyl group with 1 to 15 C-atoms or an alkyl or alkenyl group with 1 to 15 C-atoms substituted with one CN or CF3 group or with at least one halogen atom, where one or more of the CH2 groups in these alkyl or alkenyl groups can be replaced, independently of each other, by -O-, -S-, -( alpha ) -, -CO-, -CO-O-,-O-CO- or -O-CO-O- in such a way that O-atoms are not directly linked to each other; Z<1> and Z, independently of each other, are -CH2CH2-, -CH=CH-, -C=C- or a single bond, or one of the groups Z<1> and Z may also be -(CH2)4- or -CH=CH-CH2CH2-; A and A<1>, independently of each other, are trans-1,4-cyclohexylene, in which one or two non-adjacent CH2 groups may be replaced by -O-, or unsubstituted 1,4-phenylene or 1,4-phenylene substituted with one or two F- and/or Cl-atoms, where one or two CH groups in the 1,4-phenylene groups may be replaced by N; m is 0, 1, 2 or 3; o and s are 0, 1 or 2, with the proviso that (s+o) >/= 2; W is -O-, -COO- or a single bond; Q is -O-, -CH=CH- or a single bond; r is a number from 1 to 7; t is a number from 0 to 7; and Y is F, Cl, CF3, OCF3, CHF2 , OCHF2 or OCH2F. Such compounds are suitable for use as components of liquid-crystal materials.

Description

 Liquid crystalline compounds

The invention relates to liquid-crystalline compounds of the formula I

R- (A ¹ -Z ¹ ) _m - [] _s -Z- (A) _o -W- (CH ₂ ) _r -Q- (CH ₂ ) _t -YI

worin

wherein

RH, an unsubstituted, one simply by CN or CF ₃ or one at least simply by

Halogen-substituted alkyl or alkenyl radical having 1 to 15 carbon atoms, one or more CH ₂ groups in these radicals each being 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 one another,

Z ¹ and Z are each independently of one another -CH ₂ CH ₂ -, -CH = CH-,

-C≡C- or a single bond, one of the radicals Z ¹ and Z also - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ -,

A and A ¹ each independently of one another trans-1, 4-cyclohexylene, in which one or two non-adjacent CH ₂ groups can also be replaced by -O-, or unsubstituted or once or twice substituted by fluorine and / or Cl atoms

1,4-phenylene, in which one or two CH groups can also be replaced by N, m 0, 1, 2 or 3, o and s 0, 1 or 2, where (s + o) ≥ 2,

W -O-, -COO- or a single bond,

Q -O-, -CH = CH- or a single bond, r 1 to 7, t 0 to 1, and

YF, Cl, CF ₃ , OCF ₃ , CHF ₂ , OCHF ₂ or OCH ₂ F means.

The invention further relates to the use of these compounds as components of liquid-crystalline media and liquid-crystal and electro-optical display elements which contain the liquid-crystalline media according to the invention.

The compounds of the formula I can be used as components of liquid-crystalline media, in particular for

Displays that are based on the principle of the twisted cell, the guest-host effect, the effect of the deformation of aligned phases or the effect of dynamic scattering.

The substances previously used for this purpose have certain disadvantages, for example too high melting points, too low clearing points, too little stability against the action of heat, light or electrical fields, too low an electrical resistance, too high a temperature dependence of the threshold voltage, unfavorable elastic and / or dielectric properties.

The materials used to date have disadvantages, in particular in the case of displays of supertwist type (STN) with twist angles of significantly more than 220 ° or in the case of displays with an active matrix.

The object of the invention was to find new stable liquid-crystalline or mesogenic compounds which are suitable as components of liquid-crystalline media and in particular at the same time have a comparatively small number

Viscosity have a relatively high dielectric anisotropy and a high nematogenicity.

It has now been found that compounds of the formula I are particularly suitable as components of liquid-crystalline media. In particular, they have comparatively low viscosities and high nematogenicity. With their help, stable liquid-crystalline media with a wide mesophase range and advantageous values for the optical and dielectric anisotropy can be obtained. These media also have very good low-temperature behavior, i.e.

 excellent solubility in the usual LC materials, while at the same time the occurrence of smectic phases is effectively suppressed.

Liquid crystals of the formula

are already known from WO 8902425. In the

JP 59-155485-A2 is a compound of the formula

called. Finally, in EP 278665 compounds of the formula

described. From DE 31 36 624, DE 32 09 178 and DE 34 10 734 compounds of the following formulas are known:

n = 1 or 6

n = 5 or 7, m = 1, 2, 6, 10 or 11,

 From J 59 01 684 are 3-fluoro-4-substituted 4-bicyclohexylbenzenes of the formula

(R, R '= C _1-10 alkyl)

known.

WO 88 05 803 A describes esters of the general formula alkyl-COO- (CH ₂ ) _1-5 - (CF ₂ ) _8-10 -H

beschrieben. treated. In EP 0 360 521 A compounds of the general formula alkyl-O -O-CH ₂ - (CF ₂ ) _3/5 -F

described.

From WO 89 02 884 are trifluoromethyl ethers of the formula

known. Finally, in DE-OS 39 09 802 compounds of the formula (CH ₂ ) _n CHF ₂

described.

EP-OS 0 168 683 discloses liquid crystals of the following formulas: alkyl- (CH ₂ ) _n -CH = CH-alkyl

alkyl (CH₂) _n-CH=CH-alkyl

alkyl (CH ₂ ) _n -CH = CH-alkyl

Die Verbindungen der Formel I mit Y = CF₃ ermöglichen sowohl

The compounds of formula I with Y = CF ₃ allow both

STN displays with a very high slope of the electro-optical characteristic as well as displays with an active matrix with excellent long-term stability. Compared to the non-fluorine-containing compounds, the compounds according to the invention have both a higher Δε and a higher ε _¡ .

Due to their particularly favorable elastic properties, they are particularly suitable as components for TFT mixtures. With a suitable choice of r and s, the threshold voltages can be significantly reduced in both display types.

In view of the most diverse areas of use of such connections, however, it was desirable to have further connections available which have properties tailored precisely to the respective applications.

With the provision of compounds of the formula I, the range of liquid-crystalline substances which are suitable for the production of liquid-crystalline mixtures from various application-technical points of view is also very broadly widened.

The compounds of formula I have a wide range of uses. Depending on the choice of the substituents, these compounds can serve as base materials from which liquid-crystalline media are predominantly composed; However, it is also possible to add compounds of the formula I to liquid-crystalline base materials from other classes of compounds in order, for example, to influence the dielectric and / or optical anisotropy of such a dielectric and / or to optimize its threshold voltage and / or its viscosity. The compounds of the formula I are colorless in the pure state and form liquid-crystalline mesophases in a temperature range which is favorable for electro-optical use. They are stable chemically, thermally and against light.

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 relates to liquid-crystalline media containing at least one compound of the formula I and liquid-crystal display elements, in particular electro-optical display elements, which contain such media.

Above and below, R, A ¹ , A, Z ¹ , Z, W, Q, Y, m, o, r and t have the meaning given, unless expressly stated otherwise. If A ¹ and A represent a substituted 1,4-phenylene ring, the phenylene ring is preferably substituted in the 2-, 2,3- or 2,6-position by fluorine.

Z ¹ and Z are preferably a single bond or -CH ₂ CH ₂ -.

If one of the radicals Z ¹ and Z - (CH ₂ ) ₂ -, - (CH ₂ ) ₄ - or

-CH = CH-CH ₂ CH ₂ - means, the other radical Z ¹ or Z is preferably a single bond.

worin Z -(CH₂)₄- oder -CH=CH-CH₂CH₂- bedeutet und R, r, t, L, W, Q und Y die in Formel I angegebene Bedeutung haben. Preferred compounds of this type correspond to sub-formula I ', - (CH ₂ ) _r -Q- (CH ₂ ) _t -YI' -

wherein Z is - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ - and R, r, t, L, W, Q and Y have the meaning given in formula I.

Also preferred are compounds of sub-formula I ",

(CH ₂ ) _r -Q- (CH ₂ ) _t -Y I ''

wherein L is H or F and R, Z ¹ , W, Q, Y, r and t have the meaning given in claim 1. If t = 0, Q is preferably a single bond.

Y can also be H if W = 0 or a single bond. For the sake of simplicity, A ″ in the following means a 1,4-cyclohexylene radical, B a radical of the formula wherein

L is preferably F. Y is preferably F, Cl or CF ₃ and r and s are preferably 1, 2, 3 or 4. Q is preferably a single bond.

The compounds of formula I accordingly include

Compounds of the sub-formulas R-A '' - A '' - BW- (CH ₂ ) _r - (CH ₂ ) _t -Y I''a

R-A '' - A '' - BW- (CH ₂ ) _r -O- (CH ₂ ) _t -Y I''b

R-A '' - Z ¹ -A '' - BW- (CH ₂ ) _r - (CH ₂ ) _t -Y I''c

R-A "" - Z ¹ -A "-BW (CH ₂ ) _r -O- (CH ₂ ) _t -Y I''d

R-A '' - A '' - Z ² -BW- (CH ₂ ) _r - (CH ₂ ) _t -Y I''e

RA "-A" -Z ² -BW- (CH ₂ ) _r -O- (CH ₂ ) _t -Y I''f

R-A '' - Z ¹ -A '' - Z2-BW- (CH ₂ ) _r - (CH ₂ ) _t -Y I''g

R-A '' - Z ¹ -A '' - Z2-BW- (CH ₂ ) _r -O- (CH ₂ ) _t -Y I''h Among them, those of the partial formulas I''a, I''b, I "e and I" f are particularly preferred. In the compounds of the sub-formulas I "c to I" h, Z- and Z are -CH ₂ CH ₂ -, -CH = CH- or -C≡C-, preferably -CH ₂ CH ₂ -.

The compounds of

 Formula IA,

C _n H _{2n + 1} -D- (CH ₂ ) _a - _s -Z- (A) _o -O- (CH ₂ ) _r - (CH = CH) _b -CF ₃ IA

wherein n is 0 to 7, D is -O-, -CH = CH- or a single bond, a is 1 to 5, b is 0 or 1 and Z, A, o and r have the meaning given in claim 1. Particularly preferred sub-formulas of the compounds IA are

the compounds of the formula Ia,

worin a 1 bis 5, b 0 oder 1, s 1 oder 2 und A, Z, o und r die in Anspruch 1 angegebene Bedeutung besitzen. - die Verbindungen der Formel Ib, CH ₃ O- (CH ₂ ) _a - _s -Z- (A) _o -O- (CH ₂ ) _r - (CH = CH) _b -CF ₃ Ia

wherein a 1 to 5, b 0 or 1, s 1 or 2 and A, Z, o and r have the meaning given in claim 1. the compounds of the formula Ib,

worin n 1 bis 7, s 1 oder 2, b 0 oder 1 bedeuten und A, Z, o und r die in Anspruch 1 angegebene Bedeutung besitzen. - die Verbindungen der Formel Ic, C _n H _{2n + 1} - _s -Z- (A) _o -O- (CH ₂ ) _r - (CH = CH) _b -CF ₃ Ib

wherein n is 1 to 7, s is 1 or 2, b is 0 or 1 and A, Z, o and r have the meaning given in claim 1. the compounds of the formula Ic

2

worin L¹ H, F oder Cl, L² F oder Cl bedeuten und R, A- , Z¹, Z, m und s die in Anspruch 1 angegebene Bedeutung besitzen.

wherein L ^{1 is} H, F or Cl, L ² F or Cl and R, A-, Z ¹ , Z, m and s have the meaning given in claim 1.

If R in formula I is an alkyl radical and / or an alkoxy radical, this can be straight-chain or branched. It is preferably 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, furthermore methyl , Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

Oxaalkyl preferably means straight-chain 2-oxapropyl (= methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl

(= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3 -, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6 -, 7-, 8- or 9-oxadecyl. If R is an alkenyl radical, 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-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 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 in particular acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, methoxycarbonyl, methoxycarbonyl Propoxycarbonyl, butoxycarbonyl, 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 is an alkenyl radical in which a CH ₂ group adjacent to the vinyl 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-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl,

 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl,

Methacryloyloxymethyl, 2-methacryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxybutyl, 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 the substitution by CN or CF ₃ in ω-position.

If R 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 residues also include perfluorinated residues. In the case of single substitution, the fluorine or chlorine substituent can be in any position, but preferably in the ω position.

Compounds of the formula I which have wing groups R which are suitable for polymerization reactions are suitable for the preparation of liquid-crystalline polymers. Compounds of the formulas I with branched wing groups R can occasionally be important because of their 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 suitable as components for ferroelectric materials. Compounds of the formula I with S _A phases are suitable, for example, for thermally addressed displays.

Branched groups of this type 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 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 (ethoxycarbonyl) methyl, 2,2-bis (ethoxycarbonyl) ethyl,

 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) butyl, 5,5-bis (ethoxycarbonyl) hexyl.

Among these compounds of the formula I and the sub-formulas, preference is given to those in which at least one of the radicals contained therein has one of the preferred meanings indicated.

Some very particularly preferred smaller groups of compounds are those of partial formulas II to 150, in which L is H or F, n = 1-14 and r and t each 1-7.

Die Verbindungen der Formel I werden nach an sich bekannten Methoden dargestellt, wie sie in der Literatur (z.B. in den Standardwerken wie Houben-Weyl, Methoden der Organischen Chemie, Georg-Thieme-Verlag, Stuttgart Bd. IX, S. 867 ff.) beschrieben sind, und zwar unter Reaktionsbedingungen, die für die genannten Umsetzungen bekannt und geeignet sind. Dabei kann man auch von an sich bekannten, hier nicht näher erwähnten Varianten Gebrauch machen .

The compounds of the formula I are prepared by methods known per se, as described in the literature (for example in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart Vol. IX, p. 867 ff.) are described, namely under reaction conditions which are known and suitable for the reactions mentioned. Use can also be made of variants which are known per se and are not mentioned here in detail.

The compounds of formula I according to the invention with W = -O- and A = can, for. B. made by one

 Compound of formula II,

in which L is H or F and R, Z ¹ and Z have the meaning given, metalized according to the following reaction scheme and then reacted with a suitable electrophile:

1. n-BuLi / KOBu ^t

2nd B (OMe) ₃

3rd H ₂ O ₂

Die Verbindungen der Formel II mit L = F sind neu und somit auch Gegenstand der Erfindung. Weiterhin sind Verbindungen der Formel III mit L = F Gegenstand der Erfindung.

The compounds of formula II with L = F are new and thus also the subject of the invention. The invention furthermore relates to compounds of the formula III where L = F.

The invention further relates to liquid-crystalline media containing at least one compound of the formula II.

The compounds of formula I (W = -O-) (W = -O- and A = after) are obtained from the phenol of formula III obtained

known etherification methods, for example by reaction with Hal- (CH ₂ ) _r -Q- (CH ₂ ) _t -Y (Hal = I, Br or Cl) in acetone / K ₂ CO ₃ , if appropriate in the presence of catalytic amounts AI, available.

The compounds of the invention can also be derived from the bromine derivative IV (CH ₂ ) _r -Q- (CH ₂ ) _t -Y IV

Further synthetic methods for the phenyl ethers according to the invention are obvious to the person skilled in the art. For example, correspondingly substituted 1,3-difluorobenzene compounds or monofluorinated analogs (L = H) according to the above scheme can be placed in the 2-O- (CH ₂ ) _r -Q- (CH ₂ ) _t -Y-1, 3-difluoro compounds or monofluorinated analogues (L = H) are transferred and the rest are subsequently converted into

Reactions commonly used in liquid crystal chemistry (e.g. etherification or coupling, e.g. according to the article E. Poetsch, contacts (Darmstadt) 1988 (2), p. 15) are introduced.

The compounds of the formula II can be prepared, for example, according to the following synthesis scheme: Scheme 2

The synthesis of some particularly preferred compounds is detailed below:

Scheme 3 (L = H or F)

1. -H ₂ O

2. H ₂ / Pd-C

1. n-BuLi

2. B (OMe) ₃

3. H ₂ O ₂

Acetone ClCH ₂ CH ₂ CH ₂ F / K ₂ CO ₃

Scheme 4

Ultrasonic

(Luche et al. ↓

 Tetrahedron Lett.

1984, 3463)

↓ H ₂ / Pd-C

Acetone ↓ ICH ₂ CH ₂ CH ₂ Cl / K ₂ CO ₃

CH ₂ CH ₂ CH ₂ Cl

Scheme 5

Ultrasonic

Phenylether der Formel I sind durch Veretherung entsprechender Hydroxyverbindungen, vorzugsweise entsprechender Phenole, erhältlich, wobei die Hydroxyverbindung zweckmäßig zunächst in ein entsprechendes Metallderivat, z.B. durch Behandeln mit NaH, NaNH₂, NaOH, KOH, Na₂CO₃ oder K₂CO₃ in das entsprechende

Phenyl 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, for example by treatment with NaH, NaNH ₂ , NaOH, KOH, Na ₂ CO ₃ or K ₂ CO ₃ appropriate

Alkali metal alcoholate or alkali metal phenolate is converted. This can then be reacted with the corresponding alkyl halide, sulfonate or dialkyl sulfate, advantageously in an inert solvent such as. B. acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide or with an excess of aqueous or aqueous-alcoholic NaOH or KOH at temperatures between about 20 and 100 ° C.

Furthermore, the alkyl ethers can also be prepared according to Mitsunobu from the corresponding phenols and a hydroxy compound in the presence of triphenylphosphine and diethylazodicarboxylate (S. Bittner, Y. Assaf, Chemistry and Industry, 281 (1975); MS Mannas, WH Hoffman, B. Lal, AK Böse, J. Chem. Soc. Perkin I, 461 (1975)):

Scheme 6

Die Ausgangsmaterialien für die Herstellungsverfahren sind entweder bekannt oder können in Analogie zu bekannten Verbindungen hergestellt werden.

The starting materials for the production processes are either known or can be prepared analogously to known compounds.

The compounds of the formula I '''with Z = - (CH ₂ ) ₄ - can be prepared according to the following scheme (n = 1-8):

Scheme 7 (L = H or F)

-CH ₂ CH ₂ -Br

↓ chain extension using malonic ester ↓ via saponification, decarboxylation, ↓ LiAlH ₄ reduction and subsequent ↓ reaction with KBr

(CH₂)₄-Br

(CH ₂ ) ₄ -Br

↓ ZnBr ₂ / Li ultrasound (Luche et al.,

 Tetrahedron Lett 1984 3463)

In the Pd (II) -catalyzed coupling reaction, either the target product I '''is formed directly or a precursor in which the radical -O- (CH ₂ ) _r -Q- (analogously to the above methods for compounds of the formula I CH ₂ ) _t -Y is introduced. The phenyl esters of the formula I (Q = -COO-) according to the invention are obtained from the compounds of the formula II in accordance with the following reaction scheme:

Scheme 8 (L = H or F)

1. BuLi

2. CO ₂

3. H ₂ O

1. R ¹ OH, DMAP

R ¹ = (CH ₂ ) _r -X; 2. DCC

n = 1-8; if X = CF ₃ , CHF ₂ , CH ₂ F 3. (COOH) ₂ n = 2-8; if X = F, Cl, OCF ₃ , OCHF ₂

The benzene derivatives of the formula I according to the invention, in which Q denotes a single bond, are obtained according to the following schemes:

Scheme 9 (L = H or F)

1. BuLi, KO ^t Bu

THF, -100 ° C

2. X- (CH ₂ ) _n -Y

Y = Cl, F, CF ₃ , CHF ₂ X = I or Br

 n = 2-8

Schema 10 (L = H oder F) LiAlH₄

Scheme 10 (L = H or F) LiAlH ₄

CO ₂ H.

 1. DMSO / NaH

CH ₂ -O- (CH

₂)_n-1-Y

₂ ) _n-1 -Y

2. X- (CH ₂ ) _n-1 -Y

 (X = I or Br)

The trifluoroalkyl and alkenyl ethers of the formula

R- (A ¹ -Z ¹ ) _m - _s -ZAO- (CH ₂ ) _r - (CH = CH) _0.1 -CF ₃ are after

known etherification methods, for example by reacting 4-substituted phenols with shark (CH ₂ C _r - (CH = CH) _0.1 -CF _3, where shark means I, Br or Cl, in acetone and potassium carbonate, if appropriate in the presence of catalytic Amounts of potassium iodide available.

The etherification is advantageously carried out in the presence of an inert solvent. In particular, ethers such as diethyl ether, di-n-butyl ether, THF, dioxane or anisole, ketones such as acetone, butanone or cyclohexanone, hydrocarbons such as benzene, toluene or xylene, halogenated hydrocarbons such as carbon tetrachloride, dichloromethane or tetrachlorethylene are particularly suitable.

The synthesis of the trifluoroalkyl and

 -alkenyl compounds is shown in the following schemes

remove: Scheme 11

_s-Z-(A)_o-OH R- (A ¹ -Z ¹ ) _m -

_s -Z- (A) _o -OH

NaOH PPh ₃ / Br ₂

HO- (CH₂)_p-CF₃

-NaBr Br- (CH ₂ ) _r -CF ₃

HO- (CH ₂ ) _p -CF ₃

_s-Z-(A)_o-O-(CH₂}_r-CF₃ R- (A ¹ -Z ¹ ) _m -

_s -Z- (A) _o -O- (CH ₂ } _r -CF ₃

Scheme 12

R- (A ¹ Z ¹ ) _m - _s -Z- (A) _o -OH

Ph₃Br

Br- (Ch ₂ ) _r -P

Ph ₃ Br

base

Br- (CH ₂ ) _r -CH = CH-CF ₃

_s-Z-(A)_o-O-(CH₂)_p-CH=CH-CF₃ R- (A ¹ -Z ¹ ) _m -

_s -Z- (A) _o -O- (CH ₂ ) _p -CH = CH-CF ₃

Scheme 13

R- (A ¹ -Z ¹ ) _m - (L ¹ , L ² : H or F)

 DEAD

PPh ₃ HO- (CH ₂ ) _r -CF ₃

R- (A ¹ -Z ¹ ) _m - (CH ₂ ) _r -CF ₃

Die Verbindungen der Formel Ic

The compounds of formula Ic

 are from the 4-bromo-2-fluorophenol (2,2,2-trifluoroethyl) ether IB,

IB (L = H or F)

 obtainable by the reaction of 4-bromo-2-fluorophenol with 2,2,2-trifluoroethyl methyl sulfonate in the presence of 1,3-dimethyl-2-imidazolidinone (DMEU), as shown in Scheme 14,

Scheme 14 (L = H or F)

CH ₃ SO ₂ -O-CH ₂ CF ₃

N / A

DMEU

DMEU

Li / ZnCl ₂ R- (A ¹ -Z ¹ )

Ultrasonic

R- (A ¹ -Z ¹ ) _m

-OCH₂CF₃ + R-(A¹-Z¹)_m Scheme 15

-OCH ₂ CF ₃ + R- (A ¹ -Z ¹⁾ _m

Na ₂ CO ₃

R- (A¹-Z¹)_m

R- (A ¹ -Z ¹ ) _m

 Pd- (0) Cat.

Die erfindungsgemäßen flüssigkristallinen Medien enthalten vorzugsweise neben einer oder mehreren erfindungsgemäβien Verbindungen als weitere Bestandteile 2 bis 40, insbesondere 4 bis 30 Komponenten. Ganz besonders bevorzugt enthalten diese Medien neben einer oder mehreren erfindungsgemäßen Verbindungen 7 bis 25 Komponenten. Diese weiteren Bestandteile werden vorzugsweise ausgewählt aus nematischen oder nematogenen (monotropen oder isotropen) Substanzen, insbesondere Substanzen aus den Klassen der Azoxybenzole, Benzylidenaniline, Biphenyle, Terphenyle, Phenyl- oder Cyclohexylbenzoate, Cyclohexan-carbonsäure-phenyl- oder cyclohexylester, Phenyl- oder Cyclohexyl-ester der Cyclohexylbenzoesäure, Phenyl- oder Cyclohexyl-ester der Cyclohexylcyclohexancarbonsäure, Cyclohexyl-phenylester der Benzoesäure, der Cyclohexancarbonsäure, bzw. der Cyclohexylcyclohexan- carbonsäure, Phenylcyclohexane, Cyclohexylbiphenyle,

In addition to one or more compounds according to the invention, the liquid-crystalline media according to the invention preferably contain 2 to 40, in particular 4 to 30, components as further constituents. These media very particularly preferably contain 7 to 25 components in addition to one or more compounds according to the invention. These further constituents are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular substances from the classes of azoxybenzenes, benzylidene anilines, biphenyls, terphenyls, phenyl- or cyclohexylbenzoates, cyclohexane-carboxylic acid phenyl- or cyclohexyl esters, phenyl- or cyclohexyl- esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexane carboxylic acid, cyclohexyl phenyl esters of benzoic acid, cyclohexane carboxylic acid, or cyclohexylcyclohexane carboxylic acid, phenylcyclohexanes, cyclohexylbiphenyls,

Phenylcyclohexylcyclohexane, cyclohexylcyclohexane,

Cyclohexylcyclohexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-1, 3-dithiane, 1,2-diphenyls , 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4-phenyl-cyclohexyl) -ethane, 1-cyclohexyl-2-biphenyIylethane, 1-phenyl-2-cyclohexylphenylethane, optionally halogenated stilbenes, benzylphenyl ether, tolanes and substituted cinnamic acids. The

1,4-phenylene groups in these compounds 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'-L-E-R "1

 R'-L-COO-E-R "2

 R'-L-OOC-E-R "3

R'-L-CH ₂ CH ₂ -ER "4

 R'-L-C≡C-E-R "5

In formulas 1, 2, 3, 4 and 5, L and E, which may be the same or different, each independently represent a bivalent radical from the group consisting of -Phe-, -Cyc-, -Phe-Phe-,

-Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe- and -G-Cyc- as well as their mirror images formed group, where Phe unsubstituted or substituted by fluorine-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 one of the radicals L and E is Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. The media according to the invention preferably contain one or more

Components selected from the compounds of the formulas 1, 2, 3, 4 and 5, in which 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 the formulas 1, 2, 3, 4 and 5, wherein one of L and E is selected from Cyc, Phe and Pyr group 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 the formulas 1, 2, 3, 4 and 5, in which the radicals L and E are selected from the group -Phe-

Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.

R 'and R "in a smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 each independently represent alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyioxy or alkanoyloxy having up to 8 carbon atoms. In the following, this smaller subgroup becomes a group Called A and the compounds are designated with the partial formulas la, 2a, 3a, 4a and 5a. In most of these compounds, R 'and R "are different from one another, one of these radicals usually being 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 1, 2 or 3; the compounds in which R "has this meaning are denoted by the sub-formulas 1b, 2b, 3b, 4b and 5b. Particularly preferred are 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 .

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b, R 'has the meaning given for the compounds of sub-formulas la-5a and is preferably alkyl, alkenyl, alkoxy or alkoxyalkyl. In a further smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5, R "means -CN; this subgroup is referred to below as group C and the compounds of this subgroup are correspondingly given subformulas

1c, 2c, 3c, 4c and 5 c. In the connections of the

Sub-formulas 1c, 2c, 3c, 4c and 5c, R 'has the meaning given for the compounds of sub-formulas la-5a and is preferably alkyl, alkoxy or alkenyl.

In addition to the preferred compounds of groups A, B and C, there are also other compounds of the formulas 1, 2, 3, 4 and 5 with other variants of the substituents provided

in use. All of these substances can be obtained by methods known from the literature 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%,

 especially 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 the compounds from groups A and / or B and / or C contained in the respective media according to the invention is preferably 5 to 90% and in particular 10 to 90%.

The media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30%, of compounds according to the invention. Also preferred are media containing more than 40%, in particular 45 to 90%, of compounds 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 a conventional manner. As a rule, the components are dissolved in one another, advantageously at elevated temperature. By means of suitable additives, the liquid-crystalline phases according to the invention can be modified so that they can be used in all types of liquid-crystal display elements which have hitherto become known. Such additives are known to the person skilled in the art and are described in detail in the literature

(H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, pleochroic dyes for producing colored guest-host systems or substances for changing the dielectric anisotropy, the viscosity and / or the orientation of the nematic phases can be added. The following examples are intended to illustrate the invention without limiting it. "Conventional work-up" means: water is added, the mixture is extracted with methylene chloride, the mixture is separated off, the organic phase is dried, evaporated and the product is purified by crystallization and / or chromatography.

Percentages above and below mean percentages by weight. All temperatures are given 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.

The following abbreviations are used:

BuLi butyllithium

 DAST Diethylaminosulfur trifluoride

 DCC dicyclohexylcarbodiimide

 ÖIBALH diisobutyl aluminum hydride

 DMAP 2-dimethylaminopyridine

 DDQ dichlorodicyanobenzoquinone

 KOT potassium tertiary butanolate

NH ₄ Cl ammonium chloride

 THF tetrahydrofuran

 TMEDA tetramethylethylenediamine

pTSOH p-toluenesulfonic acid example 1

To a mixture consisting of 26 mmol of 1-trans-4- (trans-4-n-propylcyclohexyl) -cyclohexyl-3-fluorobenzene (prepared according to Scheme 1), 4.1 g of potassium tert-butoxide and 60 ml of THF 26 mmol n-BuLi were added dropwise at -100 ° C. After stirring for one hour at -100 ° C, 36 mmol at -85 to -90 ° C

Trimethyl borate added dropwise. The mixture is stirred for a further 0.5 h and then 42 mmol of acetic acid are added dropwise at -20 ° C. The mixture is then heated to 30 ° C. and 4.2 ml of H ₂ O _{2 are added} dropwise at this temperature and the mixture is stirred at 50 to 60 ° C. for two hours. The mixture is allowed to cool to room temperature and a 5% sodium dithione solution is added to the mixture. After phase separation and customary workup, the phenol is obtained.

The phenol obtained is reacted with methyl iodide in acetone under reflux in the presence of potassium carbonate to give the methyl ether. After the usual work-up and chromatography on silica gel with hexane, the ether is obtained in pure form. The following ethers of the formula become analogous

 manufactured.

1 ₁

 1

 Example 2

a)

The fluorophenol produced in Example 1 a) is with

 1-Chloro-3-fluoropropane in boiling acetone in the presence of potassium carbonate and a catalytic amount of potassium iodide converted to the phenol ether. After the usual work-up and chromatography on silica gel with hexane, the ether is obtained in pure form.

The fluorophenol produced in Example 1 a) is with

1-chloro-3-iodopropane analogously to Example 2a) converted into the phenol ether. The following compounds of the formula according to the invention are obtained analogously from the corresponding precursors

^

^

1

 1

₁

₁

1

 Example 3

Two drops of bromine are added to a solution of 6.0 g of magnesium shavings in 60 ml of ether. The solution of 48.2 g of 3,5-difluorobromobenzene in 60 ml of ether is then added dropwise. The mixture is stirred for a further 0.5 h and then a solution of 44.5 g of 4-trans- (4-propylcyclohexyl) cyclohexanone in 50 ml of ether is added dropwise at 20-25 ° C. to the Grignard reagent. The mixture is stirred for two hours, poured onto 500 ml of water, with 30 ml of conc. Acidified hydrochloric acid and shaken with ether. The organic phase is evaporated to the residue and then refluxed for 1 h with 1000 ml of toluene and 120 ml of 20% sulfuric acid. After phase separation and neutralization with saturated sodium bicarbonate solution, the mixture is hydrogenated with 10 g Pd / C (5%) at 1 bar and 60 ° C. It is then filtered and concentrated. The pure product is obtained after flash chromatography. K 60 ° N 87.6 ° I, Δε = 3.3

A mixture of 47 mmol of 4-trans- (4-n-propylcyclohexyl) -cyclohexyl-1-trans- (3,5-difluorobenzene), 50 mmol of TMEDA and 150 ml of THF are added at -65 ° C to -70 ° C 31 ml of n-BuLi (15% in hexane) were added dropwise and the mixture was stirred at -70 ° C. for one hour. Then at -85 to -90 ° C initially 57 mmol trimethyl borate, then at -20 ° C 65 mmol acetic acid.

Analogously to Example 2 a), the difluorophenol is reacted with 1-chloro-3-fluoropropane to give the phenol ether.

Analogously to Example 2 b), the difluorophenol prepared in Example 4 b) is reacted with 1-chloro-3-iodine-prcpan. K 50 N 157.2 I, Δε = 5.7

Example 4

A solution consisting of 1 mmol of 4-trans- (4-n-propylcyclohexyl) -cyclohexyl-1-trans- (3,5-difluorophenol), 1 mmol of tripheriylphosphine, 1 mmol of 2-fluoroethanol and 25 ml of THF becomes 1 mmol of diethyl azodicarboxylate was added dropwise at 0-10 ° C.

 The mixture is then stirred for a further hour at room temperature and then worked up as usual.

 K 82 N 165.5 I, Δε = 2.07

Analogously to Example 4 a), 1 mmol of 4-trans- (4-n-propylcyclo-hexyl) -cyclohexyl-1-trans- (3,5-difiuorphenol) is reacted with methanol. K 41 N 151.8 I, Δn = 0.088 The following compounds of the formula according to the invention are obtained analogously from the corresponding precursors

 Example 5

Analog Beispiel 3 c) wird das in Beispiel 5 a) hergestellte Produkt mit 1-Chlor-3-fluor-propan zum Phenolether umgesetzt. c)78 mmol of 1- (4- (4-n-pentylcyclohexyl) cyclohexyl) methylene triphenylphosphonium iodide and 78 mmol of 3,5-diDluorobenzaldehyde dissolved in 50 ml of THF are dissolved in -5 mmol of 78 mmol of potassium tert-butoxide in 80 ml THF added dropwise. The mixture is then stirred at the same temperature for 15 minutes and a further 1.5 hours at room temperature. The reaction mixture is hydrolyzed and neutralized with hydrochloric acid. Then it is worked up as usual.

Analogously to Example 3 c), the product prepared in Example 5 a) is reacted with 1-chloro-3-fluoropropane to give the phenol ether. c)

 Analogously to Example 3 d), the product prepared in Example 5 a) is reacted with 1-chloro-3-iodopropane to give the phenol ether.

Analogously one obtains the corresponding preliminary stages of

 Formula II (L = F) the following compounds of the formula according to the invention

 Y

Beispiel 6 / /

Example 6 //

9 mmol of the product from Example 5 a) are dissolved in 30 ml of THF, mixed with 0.3 g of 4% Pd-C and hydrogenated. The catalyst is then filtered off and the filtrate is removed in vacuo

Residue concentrated. This is chromatographed on a silica gel column with pentane.

You get analog

, K 52 N 95.1 I, Δε = 4.7

Analogously to Example 3 c), the product obtained in Example 6 a) is reacted with l-chloro-3-fluoropropane.

Analogously to Example 3 d), the product prepared in Example 6 a) is reacted with 1-chloro-3-iodopropane to give the phenol ether. The following compounds of the formula are obtained analogously from the corresponding precursors of the formula II (L = F)

Example 7

0.1 mol of 4- (4-n-pentylcyclohexyl) - (cyclohexylbutyl bromide) are placed in 150 ml of a solvent mixture of THF / toluene (1: 4), then 11.5 g of zinc bromide anhydrous and 1.4 g of lithium granules are then added. The mixture is mixed with argon and stirring for 4 hours between 0 ° C and 10 ° C

 Treated with ultrasound. The resulting organic zinc compound is mixed with 0.1 mol of 3, 5-difluoro-1-bromobenzene and 2 mol% of 1,1'-bis (diphenylphosphino) ferrocene palladium (II) dichloride and after removing the ultrasonic bath and the

Cooling stirred at room temperature for 24 h. It is decomposed with 100 ml of saturated NH ₄ Cl solution with stirring, the organic phase is separated off, the aqueous phase with toluene

 extracted. The combined organic extracts are dried, concentrated and chromatographed on silica gel.

The conversion of the difluorobenzene with BuLi and trimethyl borate to the difluorophenol is carried out analogously to Example 1.

Analogously to Example 3 c), the difluorophenol from Example 7 b) is reacted with 1-chloro-3-fluoropropane to give the phenol ether.

Analogously to Example 3 d), the product from Example 7 b) is reacted with 1-chloro-3-iodopropane. Analogously one obtains the corresponding preliminary stages of

 Formula II (L = H or F) the following compounds of the formula according to the invention

Y

₇

₇

 Example 8

26 mmol of 2-fluoroethanol and 0.1 g are added to a suspension of 26 mmol of 4-trans- (4-pentylcyclohexyl) cyclohexyl-1-trans-3,5-difluorobenzoic acid (prepared according to Scheme 7) in 160 ml of dichloromethane Given DMAP. A solution of 6.6 g of DCC in 40 ml of dichloromethane is then added dropwise with stirring. It is stirred overnight at room temperature. Oxalic acid is added, the mixture is stirred for an hour, chromatographed with hexane and recrystallized. K 63 N 148.8 I The following compounds of the formula are obtained analogously:

L 1

L 1

 1

Beispiel 9 1

Example 9

 To a suspension of 50 mmol lithium aluminum hydride in

50 ml of THF is added dropwise to a suspension of 50 mmol of 4-trans- (4-pentylcyclohexyl) -cyclohexyl-1-trans-3,5- (difluorobenzoic acid) in 150 ml of THF. The mixture is then stirred under reflux for 1 h. It is cooled in an ice bath and hydrolysed by adding 6 ml of 10% NaHCO ₃ solution. after adding 12 ml 20%

The organic phase is stripped off with sodium hydroxide solution, dried and concentrated.

A solution of 28 mmol of difluorobenzyl alcohol A in 90 ml of THF is added to a solution of 30 mmol of sodium hydroxide in 30 ml of DMSO. Then 31 mmol of 3-chloro-1-iodopropane are added to the reaction mixture and the mixture is stirred at 50 ° C. overnight. After hydrolysis and customary working up, the ether B is obtained. The following compounds of the formula are obtained analogously

Example 10 y

14.5 g (0.065 mol) of 4- (4-propylcyclohexyl) cyclohexanol are dissolved in 15 ml of THF and successively with 12.5 g (0.065 mol) of trifluorobutyl bromide, 1.2 g of cetyltrimethylammonium bromide, 5.2 g (0.13 mol ) Sodium hydroxide solution and 0.3 ml of water added. The mixture is stirred at 70 ° C. overnight. The mixture is then allowed to cool to room temperature and the mixture is taken up in diethyl ether. After the usual extractive work-up, the ether is obtained, which is purified by chromatography on silica gel (hexane: ethyl acetate = 9: 1). K 10 S _B

47 I. The following trifluoroalkyl ethers of the formula become analogous

 manufactured:

O 1 _{1 11 5 11}

Beispiel 11

Example 11

Br- (CH ₂ ) ₂ - → Br-CH ₂ -CH = CH-CF ₃

11.5 g of potassium tert-butoxide are added in portions to a suspension of 0.1 mol of Wittigsalz in 200 ml of THF at 0-10 ° C.

Then you conduct at the same temperature for so long

Trifluoroacetaldehyde gas until the orange-colored ylide suspension decolors. Then 24 hours at

Stirred at room temperature, poured onto water, neutralized, extracted several times with toluene and the toluene extract after

Evaporated to dryness and filtered through silica gel with hexane. O-CH ₂ CH = CH-CF ₃

0.065 mol of 4- (4-propylcyclohexyl) cyclohexanol, 15 ml of THF, 0.065 mol of 1,1,1-trifluoro-4-bromobut-2-ene, 1.2 g of cetyltrimethylammonium bromide, 0.13 mol of sodium hydroxide solution and 0.3 ml of water are reacted analogously to Example 1.

The following trifluoroalkenyl ethers of the formula - (CH ₂ ) _r -CH = CH-CF ₃

manufactured: O _r

nC ₅ H ₁₁

_{5 11}

Example 12

C ₅ H ₁₁ O- (CH ₂ ) ₃ -CF ₃

0.1 mol of 4- (4-pentylcyclohexyl) phenol, 0.102 mol of triphenylphosphine and 0.1 mol of trifluorobutan-4-ol are added in 250 ml

Tetrahydrofuran at room temperature with drops

0.102 mol of diethyl azodicarboxylate are added with cooling.

The mixture is then stirred overnight. After evaporation, the residue is filtered through silica gel with toluene.

The following trifluoroalkyl ethers of the formula become analogous

_s-Z-(A)_o-O-(CH₂)_r-CF₃ hergestellt: ₁₁ R-

_s -Z- (A) _o -O- (CH ₂ ) _r -CF ₃ produced: ₁₁

₁₁ O

5 ₁₁

O

O 1 ₁

O

1 ₁

_{11 5 11} O

 O

_{1 1}

1 ₁ O

_{1 1}

₁

₁

_{1 1 1}

O

 O

1 ₁

 O

1 ₁

1 ₁

 O

 7

nC ₅ H ₁₁

O 1₁

O 1 ₁

 ₁₁

 _{7  7}

1 ₁

O O

OO

nC ₅ H ₁₁ O

O

nC ₅ H ₁₁

_{1 1 1 1 1}

_{1 1 1}

Beispiel 13

_{1 1 1 1 1}

_{1 1 1}

Example 13

C ₅ H ₁₁ OCR ₂ CH = CR-CF ₃

 0.1 mol of 4- (4-pentylcyclohexyl) phenol and 0.1 mol of 1,1,1-tri-fluoro-4-bromo-but-2-ene are reacted analogously to Example 3.

_s-Z-(A)_o-O-(CH₂)_r-CH=CH-CF₃ hergestellt . O The following trifluoroalkenyl ethers of the formula R-

_s -Z- (A) _o -O- (CH ₂ ) _r -CH = CH-CF ₃ . O

1 ₁

O 1_{1 11}

O 1 ₁

 O O

O 5 ₁₁

1 ₁

 O O

 O

_{1 1 1 1}

_{1 1}

_{1 1 1 1}

Example 14

 0.085 mol of 4-bromo-2-fluorophenolate are dissolved in 100 ml of 1,3-dimethyl-2-imidazolidinone, heated to 140 ° C. and 0.09 ml of 2,2,2-trifluoroethyl methyl sulfonate are added dropwise. The solution is stirred at 140 ° C. for 24 h.

 Then 500 ml of ice water is added and worked up as usual.

 0.015 mol of 4-bromo-2-fluorophenol (2,2,2-trifluoroethyl) ether are mixed with 0.05 ml of trans-n-propylcyclohexylphenylboronic acid, 20 ml of toluene, 10 ml of ethanol, 0.030 mol of sodium carbonate and 0.86 mmol of tetrakis (triphenylphosphine) palladium (0) were added and the mixture was boiled under reflux for 2 h. After adding 100 ml

 Petroleum ether (40-80 °) is worked up as usual.

K 81 S _B 101 S _A 133 N 139.6 I, Δn = 0.152

The following compounds of the formula become analogous

manufactured: L1

K 86 I, Δn = +0.111

 K76N (62.4) I, Δn = +0.137

K96 I, Δn = +0.105

 K 84 N 104, 6 I, Δn = +0.152

K98 I, Δn = +0.111

 K85 I, Δn = +0.120

1 ₁

1 ₁ K 65 N 108.4 I, Δn = +0.142 1 ₁ K90 I, Δn = +0.113

1 ₁ K81N (78.2) I, Δn = +0.119 OO

O

Example 15

Analogously to Example 14 a), 0.085 mol of 4-bromo-2,6-difluorophenolate is mixed dropwise at 140 ° C. with 2,2,2-trifluoroethyl methyl sulfonate.

0.01 mol of trans-4-n-propylcyclohexyl bromide are placed in 15 ml of a solvent mixture of THF / toluene (1: 4) and 1.2 g of zinc chloride and 0.14 g of lithium granules are added. The mixture is treated with protective gas and stirring for 4 hours between 0 and 10 ° C with ultrasound. The organic zinc compound obtained is mixed with 0.01 mol of 4-bromo-2,6-difluorophenol (2,2,2-trifluoroethyl ether) and 2 mol% of 1,1'-bis (diphenylphosphino) ferrocene palladium (II ) added dichloride and, after removal of the ultrasonic bath and cooling, stirred for 24 hours at room temperature. 10 ml of saturated ammonium chloride solution are added, the organic phase is separated off and worked up as usual. K 5 I, Δn = 0.038

The following compounds of the formula become analogous

manufactured:

K 65 S ₃ 91 N 149.9 I; Δn = +0.093

 K 65 N 100.2 I; Δn = +0.084

K 69 N 140 I; Δn = +0.092 1 K 62 S ₃ 92 N 151.7 I; Δn = + 0.097 1 K 60 N 137.7 I; Δn = + 0.086

Example 16

0.035 mol of 3,5-difluorobenzaldehyde, 0.35 mol of propanediol and 3.5 g of p-toluenesulfonic acid are dissolved in 500 ml of toluene and boiled on a water separator.

0,044 mol des Dioxan-Derivats aus Beispiel 16 a) werden in

0.044 mol of the dioxane derivative from Example 16 a) are in

130 ml abs. THF dissolved and cooled to -70 ° C. Then 51 mmol n-BuLi are added dropwise. The mixture is left to stir at -70 ° C. for 0.5 h and then 51 mmol of trimethyl borate are added dropwise to the reaction mixture. Then allowed to warm to -20 ° C and mixed in portions with 5 ml of acetic acid. At a temperature of 30-35 ° C, 132 mmol H ₂ O ₂ are finally added dropwise to the reaction mixture. Then it is worked up as usual.

23 mmol of sodium hydride are suspended in 10 ml of DMEU and then 23 mmol of the phenol derivative from Example 16 b) in 20 ml of DMEU are added dropwise. The mixture is then stirred at 45 ° C for 1 h. 25 mmol of 2,2,2-trifluoroethyl methyl sulfonate in 5 ml of DMEU are added dropwise to the reaction mixture at 140 ° C. and the mixture is stirred at 140 ° C. for 5 h. After the hydrolysis, the mixture is acidified and the reaction mixture is worked up as usual. K 27 I; Δε = 15.76; Δn - = +0.038

The following compounds of the formula become analogous

 manufactured:

Example 17

Analogously to Example 16 c), 13 mmol of 2- [2,6-difluoro-4-hydroxyphenyl] -5-pentipyrimidine are reacted with 13 mmol of sodium hydride in 300 ml of DMEU and 25 mmol of 2,2,2-trifluoroethyl methyl sulfonate. K 66 I; Δε = 18.49; Δn = 0.106

The following compounds of the formula are obtained analogously

Claims

Claims 1. Liquid-crystalline compounds of the formula I R- (A ¹ -Z ¹ ) _m - _s -Z- (A) _o -W- (CH ₂ ) _r -Q- (CH ₂ ) _t -YI

 wherein R H, an unsubstituted, a simple by CN or CF ₃ or an at least monosubstituted by halogen 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 by -O-, -S-, -CO -, -CO-O-, -O-CO-

 or -O-CO-O- can be replaced so that O atoms are not directly linked to one another, Z ¹ and Z are each independently of one another -CH ₂ CH ₂ -, -CH = CH-, -C≡ C- or a single bond, one of the radicals Z ¹ and Z also - (CH ₂ ) ₄ - or -CH = CH-CH ₂ CH ₂ -, A and A ^{1 are} each independently trans-1,4- Cyclohexylene, in which one or two non-adjacent CH ₂ groups can also be replaced by -O-, or unsubstituted or 1,4-phenylene which is substituted once or twice by fluorine and / or Cl atoms, in which also one or two CH groups can be replaced by N. m 0, 1, 2 or 3, o and s 0, 1 or 2, where (s + o) ≥ 2, W -O-, -COO- or a single bond, Q -O-, -CH = CH- or a single bond, r 1 to 7, t 0 to 7, and YF, Cl, CF ₃ , OCF ₃ , CHF ₂ , OCHF ₂ or OCH ₂ F means. 2. Compounds of the formula in which the ring adjacent to W- (CH ₂ ) _r -Q- (CH ₂ ) _t -Y

3. Compounds of formula 1 ″,

wherein L is H or F and R, Z-, Z, W, Y, r and t have the meaning given in claim 1. 4. Compounds of the formula IA, C _n H _{2n + 1} -D- (CH ₂ ) _a - _s -Z- (A) _c -O- (CH ₂ ) _r - (CH = CH) _b -CF ₃ IA

wherein n is 0 to 7, D is -O-, -CH = CH- or a single bond, a is 1 to 5, b is 0 or 1 and Z, A, o, r and s have the meaning given in claim 1. 5. Compounds of the formula Ia CH ₃ O- (CH ₂ ) _a - _s -Z- (A) _o -O- (CH ₂ ) _r - (CH = CH) _b -CF ₃ Ia

wherein a 1 to 5, b 0 or 1, s 1 or 2 and A, Z, o and r have the meaning given in claim 1. 6. Compounds of the formula Ib, C _n H _{2n + 1} - [] _s -Z- (A) _o -O- (CH ₂ ) _r - (CH = CH) _b -CF ₃ Ib

wherein n is 1 to 7, s is 1 or 2, b is 0 or 1 and A, Z, o and r have the meaning given in claim 1. 7. Compounds of the formula Ic R- (A ¹ -Z ¹ ) _m - [-] _s -

-Z OCH ₂ CF ₃ IC

wherein L ^{1 is} H, F or Cl, L ² F or Cl and R, A ¹ , Z ¹ , Z, m and s have the meaning given in claim 1. 8. Compounds of the formula II II

wherein L is, and R, Z ¹ and Z have the meaning given in claim 1. 9. Compounds of formula III

wherein L is, and R, Z ¹ and Z have the meaning given in claim 1. 10. Compounds of formula Ib according to claim 6, characterized  characterized in that s = 2 and Z is a single bond. 11. Compounds of formula Ib according to claim 6, characterized  characterized in that s = 1 and A = 1,4-phenylene. 12. Compounds of formula Ib according to claim 10, characterized  characterized in that Z = single bond. 13. Compounds of formula Ib according to claim 10, characterized characterized in that Z = - (CH ₂ ) ₂ -. 14. Compounds of formula Ib according to claim 10, characterized characterized in that Z = - (CH ₂ ) ₄ -. 15. Compounds of formula IV

wherein L, W, Q, Y, r and t have the meaning given in claim 1. 16. Compounds of formula IB

where L is H or F. 17. Process for the preparation of the compounds IB

where L is H or F. characterized in that 4-bromo-2-fluorophenolate or 4-bromo-2,6-difluorophenolate is reacted with 2,2,2-trifluoroethyl methyl sulfonate in the presence of 1,3-dimethyl-2-imidazoldinone. 18. Use of compounds of the formulas I, II and III as components of liquid-crystalline media. 19. Liquid-crystalline medium with at least two liquid-crystalline components, characterized in that it contains at least one compound of the formula I. 20. Liquid-crystalline medium with at least two liquid-crystalline components, characterized in that it contains at least one compound of the formula II. 21. Liquid crystal display element, characterized in that it contains a liquid crystalline medium according to claim 19 or 20. 22. Electro-optical display element, characterized in that it contains a liquid-crystalline medium as claimed in claim 19 or 20 as a dielectric.