GB2410745A - Liquid crystalline cholestanyl derivatives - Google Patents

Description

1 241 0745 Cholestanyl derivatives The present invention relates to

cholestanyl derivatives, to the use thereof as component(s) in liquidcrystalline media, and to liquid-crystal and electro-optical display elements which contain the liquid-crystalline media according to the invention.

The cholestanyl derivatives according to the invention can be used as components of liquid-crystalline media, in particular for displays based on the principle of the twisted cell, the guest-host effect, the effect of defor mation of aligned phases DAP or ECB (electrically controlled birefrin gence), the IPS effect (in plane switching) or the effect of dynamic scat tering.

The substances employed hitherto for this purpose all have certain disad vantages with respect to some of their properties, for example low stability to the action of heat, light or electric fields, unfavourable elastic and/or dielectric properties.

Furthermore, liquid-crystal mixtures having very low birefringence (opti cal anisotropy; An) are increasingly becoming necessary for applications of liquid crystals or liquid-crystalline mixtures, in particular in reflective and transflective display devices and in television sets with a liquid crystal display. At the same time, it is desirable or in many cases necessary for the dielectric anisotropy () of these mixtures to be in the range from highly positive to highly negative values.

For mobile applications in particular, both good low-temperature stability and an adequately high clearing point of these mixtures are of importance.

However, mesogenic or liquid-crystalline compounds having very low birefringence which have been disclosed to date are usually distin guished by an extremely strong tendency towards the formation of smectic phases; furthermore, they frequently do not form a nematic - 2 phase. The few known compounds of negative An have extremely high rotational viscosities and only exhibit a low As (cf., for example, V. Reiffenrath, M. Bremer in.'Anisotropic Organic Materials" (R. Glaser, P. Kaszynski, Eds.), ACS Symposium Series 798, American Chemical Society, Washington, DC, 2001, 195-205). In addition, the solubilityof these compounds is limited.

The invention thus has the object of finding novel stable liquid-crystal line or mesogenic compounds which are suitable as components of liquidcrystalline media, in particular for TN, STN, IPS and TFT displays.

A further object of the present invention is to provide liquidcrystalline compounds which, at the same time as low birefringence, are able to form a nematic phase, preferably of large width. They should furthermore have a high clearing point and good solubility.

Surprisingly, it has been found that these objects are achieved in accordance with the invention by the cholestanyl derivatives of the for mula I CH3 )- Cam 1 H 'CF2o-MG in which -MG stands for-[-A'4-Z'3-]c-[-A43-Z'2-]b-l-A'2-Z''-]a-A''-R11, which prefera- bly represents a mesogenic group; where R" denotes H. -B(OH)2, -B(ORX) (ORY), halogen, ON, SFs, NCS or a lin ear or branched, optionally chiral alkyl radical having from 1 to 15 C atoms which is unsubstituted or mono- or polysubstituted by CN, F. Cl, Br and/or 1, where, in addition, one or more CH2 groups of the alkyl radical may each, independently of one another, be replaced - 3 - by -O-, -S-, -SO2-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CH=CF-, -CF=CF- or-C_C- in such a way that heteroatoms in the chain are not linked directly to one another, where Rx and RY either, independently of one another, denote an alkanyl or alkenyl radical having up to 8 carbon atoms or together form an alkylene bridge having up to 8 carbon atoms in the bridge which is optionally substituted by one or more C'4- alkanyl radicals; A", Am, A'3 and A'4 each, independently of one another, denote trans-1,4-cyclohexylene, in which, in addition, one or more non adjacent CH2 groups may be replaced by -O- and/or-S-, 1,4 phenylene, in which one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by F. Cl, CF3, CN, CH3, OCH3, OCHF2 and/or OCF3, or a radical from the group consisting of 1,4-bicyclo[2.2.2] octylene, piperidine-1,4 dlyl, naphthalene-2,6-dlyl, decahydronaphthalene- 2,6-dlyl and 1,2,3,4-tetrahydronaphthalene-2,6-dlyl, in which, in addition, one or more H atoms may be replaced by F. Cl, CF3, CN, CH3, OCH3, OCHF2 and/or OCF3; z'' z'2 and Z'3 each, independently of one another, denote -CH2O-, -OCH2-, -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CF2CF2-, -CH2CF2-, -CF2CH2-, -CH2CH2-, -CH=CH-, -CH=CF-, -CF=CH-, -CF=CF-, -CF=CF-COO-, -O-CO-CF=CF-, -C-C- or a single bond; a, b and c each, independently of one another, denote 0 or 1; and n can adopt the value 0 or 1.

It should be noted here that the formula I can also be reproduced as follows with the same contents: -: 1 MGCF2J Furthermore, for reasons of simplicity, the cholestanyl group of the compound of the formula I may also be abbreviated to "Chol" for the

purposes of the present description:

: Chol

H

The cholestanyl derivatives of the formula I according to the invention are eminently suitable as components of liquid-crystalline media. They can be used to obtain stable, liquid-crystalline media, in particular suit able for TFT or STN displays.

In particular, the cholestanyl derivatives according to the invention are distinguished by high curing points, broad nematic phase ranges and good solubility.

Through a suitable choice for the ring members and/or the terminal substituents, the physical properties of the cholestanyl derivatives according to the invention can be varied in broad ranges. Thus, it is possible, for example, to obtain cholestanyl derivatives according to the invention having negative, (virtually) neutral, slightly positive or strongly positive values of the dielectric anisotropy with in each case small to very small values of the optical anisotropy.

Liquid-crystalline media having very small values of the optical anisot ropy are of particular importance for reflective and transflective applica tions, i.e. applications in which the respective LCD experiences no or only supporting backlighting.

The provision of the cholestanyl derivatives according to the invention very generally considerably broadens the range of liquid-crvstalline substances which are suitable, from various applicational points of view, for the preparation of liquid-crystalline mixtures. - 5

The cholestanyl derivatives according to the invention have a broad range of applications. Depending on the choice of substituents, these com pounds can serve as base materials of which liquid-crystalline media are predominantly composed; however, it is also possible to add liquidcrystal line base materials from other classes of compound to the cholestanyl derivatives according to the invention in order, for example, to modify the dielectric and/or optical anisotropy of a dielectric of this type and/or to optimise its threshold voltage and/or its viscosity.

Unexpectedly, the substances do not have a significant HTP (= Helical twisting powers), in spite of the large chiral cholestanyl group (which has 9 asymmetric centres), either in the pure substance or in a liquidcrystalline mixture. This also facilitates their use in mixtures which do not comprise a chiral dopant.

In the pure state, the cholestanyl derivatives according to the invention are colourless and form liquid-crystalline mesophases in a temperature range which is favourably located for electro-optical use. They (and the liquid crystalline media comprising them) also have good low-temperature stabil ity. They are stable chemically, thermally and to light.

The present invention furthermore relates to the use of compounds of the formula I as component(s) in liquid-crystalline media.

The present invention likewise relates to liquid-crystalline media having at least two liquid-crystalline components which comprise at least one com pound of the formula 1.

The present invention also relates to liquid-crystal display elements, in particular electro-optical display elements, which contain, as dielectric, a liquid-crystalline medium according to the invention.

Particular preference is given to reflective and transflective liquidcrystal display elements and other liquid-crystal displays having low birefringence - 6 An, so-called "low An mode displaysn, such as, for example, reflective and transflective TN displays.

The meaning of the formula I includes all isotopes of the chemical ele meets bound in the compounds of the formula 1. If the radical -MG in the compound of the formula I according to the invention has radicals or sub stituents which can be in the form of optically active radicals or substitu ents - since they have, for example, a centre of asymmetry these are also encompassed by the present invention. It goes without saying here that the cholestanyl derivatives of the formula I according to the invention can be in isomerically pure form, for example as pure enantiomers or dia stereomers, or in the form of a mixture of a plurality of isomers, for exam ple as a racemate.

Preferred cholestanyl derivatives of the formula I are those in which R" denotes F. Cl, Br, 1, SO2CF3, cyano or a straight-chain or branched alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoroalkenyl radical having up to 8 carbon atoms. With respect to the radicals F. Cl, Br, 1, SO2CF3 and ON, F and Cl are particularly preferred, in particular F. Compounds according to the invention where R" = Br or I are particularly suitable for the preparation of further compounds of the formula I according to the invention by C-C coupling reactions known from the prior art, preferably catalysed by transition metals. With respect to the straight-chain or branched alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoro alkenyl radicals which are preferred for R", the straight-chain (un branched) radicals are particularly preferred. Very particularly preferred alkanyl radicals for R" are methyl, ethyl, npropyl, n-butyl, n-pentyl, n-hexyl, n-heptyl and n-octyl, in particular ethyl, n-propyl and n-pentyl. Very particularly preferred fluoroalkanyl radicals for R" are mono-, di-, tri- and perfluorinated straight-chain alkanyl radicals, in particular-CH2F, -CHF2, -CF3, -CH2CF3 and CF2CF3. Alkoxy radicals which are very particularly preferred for R" are methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n- hexyloxy, n-heptyloxy and n-octyloxy, in particular methoxy, ethoxy, n- propoxy and n-pentoxy. Very particularly preferred fluoroalkoxy radicals for R" are mono-, di-, triand perfluorinated straight-chain alkoxy radicals, in particular-OCHF2 and -OCF3. Very particularly preferred straight-chain - 7 alkenyl radicals for R" are vinyl, 1 E-propenyl, 1 E- butenyl, 1 E-pentenyl, 1 E-hexenyl, 1 E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E- heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and 7-octenyl. Groups having up to 5 carbon atoms are particularly preferred here. Fluoroalkenyl radicals which are very particularly preferred for R" are-CH=CH-CF3 and -CF=CF-CH3.

Preferred cholestanyl compounds of the formula I are those in which n is equal to 0.

It is furthermore preferred for the ring A', and the optionally present rings A'2, A'3 and A44 to each, independently of one another, stand for {0 - 0} {A or \ / . The optional rings A'2, AT and A'4 are particularly preferably, independently of one another, , F or It is furthermore preferred for either no or one further or two further rings selected from A'2, A'3 and A'4 to be present in the compound of the for mula I besides the ring A'', i.e. a+b+c in the formula I is 0, 1 or 2.

It is furthermore preferred for z'', z'2 and Z'3 in the compound of the for mula I each to denote, independently of one another, a single bond, -CF20-, -OCF2-, -CO-O- or -O-OC-, particularly preferably a single bond, 8 -CF2O- or -OCF2-. It is very particularly preferred for none or one of z'', Z'2 and Z'3 to denote something other than a single bond.

In a preferred embodiment of the present invention, the ring A'' is selected from {me, No, on, {/ or Em}.

In this embodiment, it is furthermore particularly preferred for R" to denote a branched or in particular straight-chain alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoroalkenyl radical having up to 8 carbon atoms.

R" then very particularly preferably adopts the above-mentioned particu larly preferred meanings in respect of alkanyl, fluoroalkanyl, alkoxy, fluoro- alkoxy, alkenyl or fluoroalkenyl radicals.

In a further preferred embodiment of the present invention, A'' stands for F a, r or F≥<F 20. In this embodiment, it is furthermore particularly preferred for R'' to denote F. Cl, Br or a branched or in particular straight-chain alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoroalkenyl radical having up to 8 carbon atoms. R" then very particularly preferred adopts the above-mentioned particularly preferred meanings in respect of alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoroalkenyl radicals or stands for F or Cl, in particular F. A group of preferred compounds of the formula I are compounds which, besides the cholestanyl ring system, contain only one further ring A" in the -MG group and have the formula la, where A" and R" have the above mentioned meanings: - 9 - -<: H 'CF2O-Al' R" A further group of preferred compounds of the formula I are compounds which, besides the cholestanyl ring system, contain a ring A'' and a sec- ond ring A'2 in the -MG group and have the formula lb, where A'', A'2, Z" and R'' have the above-mentioned meanings: CH3 ( lb 'CF2O-A'2 z'' A" R" A third group of preferred compounds of the formula I are compounds which, besides the cholestanyl ring system, contain a ring A" and a sec ond ring A'2 and a third ring A'3 in the -MG group and have the formula Ic, where A'', A'2, A'3, z'', Z'2 and R'' have the above- mentioned meanings: ^5 Ic H CF2O-A'3 Zi2 A'2 Z'' A'' R', In respect of this third group, it is particularly preferred for at least one of Z'2 and Z'' to be a single bond and the other to represent a -CF20- bridge.

Rings A'3, A42 and A'' are furthermore preferably selected in such a way that (1) if A'3 represents an aromatic ring and A'2 represents a non-aromatic ring, A" likewise represents a non-aromatic ring; and (2) if A'3 represents a non-aromatic ring, A'2 and A" also represent non-aromatic rings. - 10

Particularly preferred compounds of the formula la encompass the following formulae: Chol-OF OR'' 11 Chd-CF2O$R" 12 Choi-CF2OR11 13 where Chol is as defined above, and R'' can adopt the above-mentioned meanings or preferred meanings.

Particularly preferred compounds of the formula lb encompass the follow ing formulae: Chol-CF2O-OR" 14 Choi-CF2OR71 15 Chol-CF2OR" i6

F

Chol-CF2OR1' 17

OF OFF

Chol-CF2OR1' 18

OF OF

Chol-CF2OR1' 19

F F - 11

Cho'-CF2O IRK 110 Cho'-CF2OR', 111 Cho'-CF2OR" 112 Chol-CF2OR" 113 ChdCF2O:{ WAR" 114 Cho'-CF2OR" 115 Chol-CF2OR" 116 Cho'-OF o R'' 117 Chd-OF O:}R 118 where Chol is as defined above, and R'' can adopt the abovementioned meanings or preferred meanings.

3 Particularly preferred compounds of the formula lo encompass the follow ing formulae: Cho'-CF2O FIR" 1 1 9 Cho'-CF2OR'' 120 - 12 Chol-CF2OR11 121 Cho'-CF2O-R11 122 Chol-CFzOR11 123 Chol-CF2OR11 124 Chol-OF oR11 125 CholCF2ORl' 126 Chol-CF2OR1' 127

F F

Cho'-CF2OR1' 128

F F F

Chol-CF2O j_: R11 129

F

Chol-CF2O I R' 130 - 13

F F

Chol-CF2O g g < R1 131 Cho'-CF2OR" 132 Chd-CF2OR'' 133 Chd-CF2OR" 134 Cho'-CF2OR" 135 Chol-CF2O{ >WRY 136 Chol-CF2O}R" 137 Chol-CF2OR" 138 Cho'CF2OR" 139

F F

Chd-CF2OR" 140 Cho'-CF2OR" 141 Cho'-CF2OR" 142 - 14 Cho'-CF2O OR" 143 Cho!-CF2O OR" 144 Cho'-CF2OR" 145 Chol-CF2OR" 146 Chol-CF2O R" 147 where Chol is as defined above, and R" can adopt the above-mentioned meanings or preferred meanings.

In the above, particularly preferred formulae, R'' preferably denotes alkanyl, fluoroalkanyl, alkoxy or fluoroalkoxy having from 1 to 8 carbon atoms or alkenyl or alkenyloxy having from 2 to 8 C atoms. If R" is bonded directly to an aromatic ring, R" in the above, particularly preferred formu iae preferably also denotes F or Cl.

Of the above preferred compounds 11-147, very particular preference is given to the compounds for which n is equal to 0.

In connection with the present invention, the term "alkyl" - unless defined otherwise elsewhere in this description or in the claims - denotes a straight-chain or branched aliphatic hydrocarbon radical having from 1 to (i.e. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15) carbon atoms; this radical is unsubstituted or mono- or polysubstituted by fluorine, chlorine, bromine, iodine and/or cyano, where the polysubstitution can take place with identical or different substituents.

If this alkyl radical is a saturated radical, it is also referred to as "alkanyl".

Furthermore, the term "alkyl" also encompasses hydrocarbon radicals which are unsubstituted or correspondingly mono- or polysubstituted, in particular by identical or different F, Cl, Br, I and/or-CN radicals, and in which one or more CH2 groups may be replaced by -O- ("alkoxy", "oxa alkyl"), -S- ("thioalkyl"), -SO2-, -CH=CH- ("alkenyl"), -C--C- ("alkynyin) , -CO O- or-O-CO- in such a way that heteroatoms (O and S) in the chain are not linked directly to one another. Alkyl is preferably a straightchain or branched, unsubstituted or substituted alkanyl, alkenyl or alkoxy radical having 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms. If alkyl denotes an alkanyl radical, this is preferably methyl, ethyl, n-propyl, i- propyl, n-butyl, i-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl; CF3, CHF2, CH2F; CF2CF3. The alkanyl radical is particularly preferably straight-chain and Since one or more CH2 groups in an alkyl radical may be replaced by -O-, the term "alkyl" also encompasses Ualkoxy" or "oxaalkyl" radicals. Alkoxy is taken to mean an O-alkyl radical in which the oxygen atom is bonded directly to the group substituted by the alkoxy radical or to the substituted ring, and alkyl is as defined above; alkyl is preferably then alkanyl or alkenyl. Preferred alkoxy radicals are methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy, heptyloxy and octyloxy, where each of these radicals may also be substituted, preferably by one or more fluorine atoms. Alkoxy is particularly preferably -OCH3, -OC2H5, -O-n-C3H7, -O-n-C4Hg, -O-t-C4Hg, -OCF3, -OCHF2, -OCH2F or-OCHFCHF2. In connection with the present invention, the term Uoxaalkyl" denotes alkyl radicals in which at least one non-terminal CH2 group has been replaced by -O- in such a way that no adjacent heteroatoms (O and S) are present. Oxaalkyl preferably encom passes straight-chain radicals of the formula -CaH2a±O-(CH2)b-, where a and b each, independently of one another, denote 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; a is particularly preferably an integer from 1 to 6, and b is 1 or 2.

If one or more CH2 groups in an alkyl radical as defined above have been replaced by sulfur, a "thioalkyl" radical is present. UThioalkyl" preferably encompasses a straight-chain radical of the formula -CaH2a±S] CH2)b-, whereais1,2,3,4,5,6,7,8,90r10,andbisO, 1,2,3,4,5,6,7,8,90r 10; a is particularly preferably an integer from 1 to 6, and b is 0, 1 or 2. The thioalkyl radical may likewise be substituted by F. Cl, Br, I and/or -CN and - 16 ln connection with the present invention, the term "alkenyl" denotes an alkyl radical as defined above in which one or more - CH=CHgroups are present. If two -CH=CH- groups are present in the radical, this may also be referred to as alkadienyl". An alkenyl radical may contain from 2 to 15 (i.e. 2,3,4,5,6,7,8,9,10,11,12,13,140r15)carbonatomsandis branched or preferably straight-chain. The radical is unsubstituted or mono- or polysubstituted, in particular by identical or different F. Cl, Br, I and/or ON radicals. Furthermore, one or more CH2 groups may each, in dependently of one another, be replaced by -0-, -S-, -C-C-, -CO-O- or -OC-O- in such a way that heteroatoms (O and S) are not bonded directly to one another. If the CH=CH group carries a radical other than hydrogen on the two carbon atoms, for example if it is a non-terminal group, the CH=CH group can exist in two configurations, namely as the E isomer and the Z isomer. In general, the E isomer (trans) is preferred. The alkenyl radical preferably contains 2, 3, 4, 5, 6 or 7 carbon atoms and denotes vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 2-propenyl, 2E-butenyl, 2E-pentenyl, 2E-hexenyl, 2E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hex enyl, 4Z-heptenyl, 5-hexenyl or 6-heptenyl. Particularly preferred alkenyl radicals are vinyl, 1 E-propenyl and 3E-butenyl.

If one or more CH2 groups in an alkyl radical have been replaced by -C-C-, an alkynyl radical is present. Replacement of one or more CH2 groups by -CO-O- or-O-CO- is also possible. The following radicals are preferred here: acetoxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetoxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetoxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 2-acetoxypropyl, 3-propionyloxypropyl, 4-acetoxybutyl, methoxycarbonyl, ethoxycarbonyl, propcxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonyl methyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, butoxycarbonyl methyl, 2(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(propoxy carbonyl) ethyl, 3-(methoxycarbonyl)propyl, 3-(ethoxycarbonyl)propyl and 4-(methoxycarbonyl)butyl. - 1 7

If a CH2 group in an alkyl radical has been replaced by unsubstituted or substituted -CH=CH- and an adjacent CH2 group has been replaced by CO, COO or O-CO, this radical may be straight-chain or branched. It is preferably straight-chain and has from 4 to 12 C atoms. Accordingly, it particularly preferably denotes acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyl oxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl or 8-methacryloyloxyoctyl.

If the alkyl radical, alkanyl radical, alkenyl radical or alkoxy radical is sub stituted by at least one halogen, this radical can also be referred to as haloalkyl (for example fluoroalkyl), haloalkanyl (for example fluoroalkanyl), haloalkenyl (for example fluoroalkenyl) or haloalkoxy (for example fluoro alkoxy) and is preferably straight-chain. Halogen is preferably F or Cl. In the case of polysubstitution, halogen is preferably F. The resultant radicals also include perfluorinated radicals. In the case of monosubstitution, the fluorine or chlorine substituent can be in any desired position, but prefera bly in the a>- position.

Compounds of the formula I containing a branched wing group R'' may occasionally be of importance owing to better solubility in the conventional, liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Smectic compounds of this type are suitable as components of ferroelectric materials.

Branched groups of this type preferably contain not more than one chain branch. Preferred branched radicals R" are isopropyl, 2-butyl (= 1-methyl propyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3methyl butyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2propylpentyl, iso propoxy, 2-methylpropoxy, 2- methyl butoxy, 3-methyl butoxy, 2-methyl pentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy, 1methylhexyloxy and 1 -methylheptyloxy. - 18

In connection with the present invention, "alkylene" (orUalkylene bridge") stands for a divalent aliphatic hydrocarbon radical having 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms in the chain, which may optionally also be mono- or polysubstituted by C, .-alkanyl, where the polysubstitution can take place with identical or different substituents. "Alkylene" or alkylene bridge" pref erably stands for a straight-chain, saturated aliphatic radical having 1, 2, 3, 4, 5 or 6 carbon atoms which is unsubstituted or mono- or disubstituted by methyl, in particular for -CH2CH2CH2- or -CH2C(CH3)2CH=.

In connection with the present invention, "halogen" stands for fluorine, chlorine, bromine or iodine.

Of the compounds of the formula I and the sub-formulae, preference is given to those in which at least one of the radicals present therein has one of the preferred meanings indicated.

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, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditions which are known and suitable for the said reactions. Use can be made here of variants which are known per se, but are not mentioned here in greater detail.

The compounds of the formula I can be prepared, for example, in accor dance with the following reaction schemes or analogously thereto. Further synthetic methods are given in the examples.

Scheme 1 shows the preparation of the central synthetic unit B1 starting from commercially available cholestanone A1 by a process known from the literature (D. Seebach, M. Kolb, Liebigs Ann. Chem. 1977, 811-829).

Scheme 2 shows the preparation of the analogous synthetic unit B2 start ing from the cholestanone derivative A2 by the above-mentioned process according to D. Seebach. Starting from B1 and B2, the compounds of the formula I according to the invention are then accessible in accordance with the following schemes 3 to 6, where n stands for 0 if A1 is reacted and n - 19 stands for 1 if A2 is reacted. In these schemes, R'' and alkoxy have the meaning indicated above. L'' and L'2, independently of one another, denote H or F. Scheme 1: \ \ 2-Trimethylsiiyl-1,3-dithiane, n-butyllithium, THE; 0 H -20.C-> RT A1 1 5 <\> Saws H

H

S B1

RT = room temperature Scheme 2: 25: \( 2-Trimethylsilyl-1,3-dithiane, e-but lithium, THF; J H -20 C -> RT A2 30,; B2 RT = room temperature Scheme 3: 1. CF3SO3H- CH2CI2; -70.C (5 min) -A H. C \ 70(C); <: HO<R" L12 0 H NEt3, CH2C12; -70.C R L1t 3. NEt. 3 HF; -70.C 4. DBH; -70.C RT RT = room temperature DBH = 1,3-dibromo-5,5- dimethylhydantoin Scheme 4:

-

a) F F Bra 1. HS(CH2)3SH. OS: F CF3SO3H F 2. Ac2O CF3SO 3. Et2O 1. NEt3, CH2CI2,-70 C L,2R HORi' L12 2. NEt33HF 3. Br2; -70 C to RT - 21 b) 1 CF3SO3H, CH2CIz; -70.C (5 min) -a H. C \ RT (30 min) -> 3 I i JO / -70.C <: HOBr FO- At. ; H NEt3, CH2CI2; -70.C B F 3 NEt3 3 HF; -70.C 4 DBH; -70.C RT 1 n-Bu THF,-78.C 2 B(OMe)3, -78.C RT H3C | H | > 3 HCI,^ - / 15;F,O: i H Pd(PFt3L (it.), borate buffer pH 9, toluene; 80.C

_ Be

L ir0 F L12 RT = room temperature DBH = 1,3-dibromo-5,5-dimethylhydantoin n-BuLi = n-butyllithium - 22 Scheme 5: 1. CF3SO:H, CH2CI2; -70.C (5 min) -> H C RT(30min)-> ^t L B11B2 ' 2 '= I H H HOBr [0'

J F F

NEt3, CH2CI2; -70 C Br 3. NEt3 3 HF; -70 C 0 4. D8H; -70 C -> RT H3C \ c_ Pd(PPh3)4 (cat), H. C < borate buffer pH 9, 1 / Scene; 80.C ' H H alkoxyB(OH)2 A: F): F F alkoxy F F RT = room temperature DBH = 1,3-dibromo-5,5-dimethylhydantoin Scheme 6: 1. CF3SO3H. CH2CI2; -70 C (5 min) -> RT (30 ndn) -> -70 C B1/82 - 2 alkyl H3C-_ NEt3, CH2a2; -70.C H3C > \< 3. NEt33 HF; -70.C / 4.DBH;-70.C->RT o > J H alky RT = room temperature DBH = 1,3-dibromo-5,5- dimethylhydantoin - 23 The starting materials are either known or can be prepared analogously to known compounds.

If desired, the starting materials can also be formed in situ by not isolating them from the reaction mixture, but instead immediately converting them further into the compounds of the formula 1.

The liquid-crystalline media according to the invention preferably comprise from 2 to 40, particularly preferably from 4 to 30, components as further constituents besides one or more compounds according to theinvention. In particular, these media comprise from 7 to 25 components besides 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 the azoxy benzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl esters of cyclohexanecarboxylic acid, phenyl or cyclohexyl esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, cyclohexylphenyl esters of benzoic acid, of cyclohexanecarboxylic acid or of cyclohexylcyclohexanecar boxylic acid, phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexyl cyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-biscyclohexylbenzenes, 4,4'-biscyclohexylbiphenyls, phenyl- or cyclo hexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyl dioxanes, phenyl- or cyclohexyl-1,3-dithianes, 1,2-diphenylethanes, 1,2di cyclohexylethanes, 1 -phenyl-2-cyclohexylethanes, 1 -cyclohexyl-2-(4phenyl cyclohexyl)ethanes, 1-cyclohexyl-2-biphenylylethanes, 1-phenyl-2cyclo hexylphenylethanes, optionally halogenated stilbenes, benzyl phenyl ethers, tolans and substituted cinnamic acids. The 1,4-phenylene groups in these compounds may also be fluorinated.

The most important compounds suitable as further constituents of the media according to the invention can be characterized by the formulae 1, 2, 3, 4 and 5: R'-L-E-R" 1 R'-L-COO-E-R" 2 - 24 R'-L-OOC-E-R" 3 R'-L- CH2CH2-E-R" 4 R'- L-C-C- E- R N 5 In the formulae 1, 2, 3, 4 and 5, L and E, which may be identical or different, each, independently of one another, denote a divalent radical from the group formed by-Phe-,-Cyc-,- Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-,-Thp-, -Phe-Thp-, -Cyc-Thp-, -G-Pheand -G-Cyc- and their mirror images, where Phe denotes unsubstituted or fluorine-substituted 1,4-phenylene, Cyc denotes trans-1,4-cyclohexylene or 1,4-cyclohexenylene, Pyr denotes pyrimidine-2,5-dlyl or pyridine-2,5-dlyl, Dio denotes 1,3-dioxane-2,5- diyl, Thp denotes tetrahydropyran-2,5-dlyl and G denotes 1-ethylene- (trans) cyclohexan-4-yl.

One of the radicals L and E is preferably Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. The media according to the invention preferably comprise one or more components selected from the compounds of the formulae 1, 2, 3, 4 and 5 in which L and E are selected from the group consisting of Cyc, Phe and Pyr and simultaneously one or more components selected from the compounds of the formulae 1, 2, 3, 4 and 5 in which one of the radicals L and E is selected from the group consisting of Cyc, Phe and Pyr and the other radical is selected from the group consisting of -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally one or more components selected from the compounds of the formulae 1, 2, 3, 4 and 5 in which the radicals L and E are selected from the group consisting of -Phe-Cy>, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.

R' and/or R" each, independently of one another, denote alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy having up to 8 C atoms, -F.

-Cl, -CN, -NCS, -(0)'CHk+)FkCI', where i is 0 or 1, k and I are 0, 1, 2 or 3, and where the sum (k + I) is 1, 2 or 3.

In a smaller sub-group of the compounds of the formulae 1, 2, 3, 4 and 5, R' and RN each, independently of one another, denote alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy having up to 8 C atoms. This smaller sub-group is called group A below, and the compounds are referred to by - 25 the sub-formulae 1a, 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 (oxaalkyl).

In another smaller sub-group of the compounds of the formulae 1, 2, 3, 4 and 5, which is referred to as group B. R" denotes -F. -Cl, -NCS or -(0)'CHk+)FkCI', where i is 0 or 1, k and I are 0, 1, 2 or 3, and where the sum (k + I) is 1, 2 or 3. The compounds in which R" has this meaning are referred to by the sub-formulae 1 b, 2b, 3b, 4b and fib. Particular preference is given to those compounds of the sub-formulae 1b, 2b, 3b, 4b and 5b in which R" has the meaning -F. -Cl, -NCS, -CF3, -OCHF2 or -OCF3.

In the compounds of the sub-formulae 1 b, 2b, 3b, 4b and fib, R' has the meaning indicated in respect of the compounds of the sub-formulae 1a to 5a and is preferably alkyl, alkenyl, alkoxy or alkoxyalkyl.

In a further smaller sub-group of the compounds of the formulae 1, 2, 3, 4 and 5, R" denotes -CN; this sub-group is referred to below as group C, and the compounds of this sub-group are correspondingly described by sub formulae 1c, 2c, 3c, 4c and 5c. In the compounds of the sub-formulae 1c, 2c, 3c, 4c and 5c, R' has the meaning indicated in respect of the compounds of the sub-formulae 1a to 5a and is preferably alkyl, alkoxy or alkenyl.

Besides the preferred compounds of groups A, B and/or C, other com pounds of the formulae 1, 2, 3, 4 and 5 having other variants of the proposed substituents are also customary. All these substances are obtainable by methods which are known from the literature or analogously thereto.

Besides compounds of the formula I according to the invention, the media according to the invention preferably comprise one or more compounds selected from groups A, B and/or C. The proportions by weight of the com pounds from these groups in the media according to the invention are pre ferably: - 26 group A: from O to 90%, preferably from 20 to 90%, particularly pref erably from 30 to 90%; group B: from O to 80%, preferably from 10 to 80%, particularly preferably from 10 to 65%; group C: from O to 80%, preferably from 5 to 80%, particularly preferably from 5 to 50%; where the sum of the proportions by weight of the group A, B and/or C com pounds present in the respective media according to the invention is prefera bly from 5 to 90% and particularly preferably from 10 to 90%.

The media according to the invention preferably comprise from 1 to 40%, particularly preferably from 5 to 30%, of the compounds of the formula I according to the invention. Preference is furthermore given to media com prising more than 40%, particularly preferably from 45 to 90%, of com pounds of the formula I according to the invention. The media preferably comprise one, two, three, four or five compounds of the formula I accord ing to the invention.

The liquid-crystal mixtures are prepared in a manner which is conventional per se. In general, the desired amount of the components used in lesser amount is dissolved in the components making up the principal constitu ent, preferably at elevated temperature. It is also possible to mix solutions of the components in an organic solvent, for example in acetone, chloro form or methanol, and to remove the solvent again, for example by distilla tion, after thorough mixing. It is furthermore possible to prepare the mix tures in other conventional manners, for example by using premixes, such as, for example, homologue mixtures, or using so-called "multibottle" sys tems.

The dielectrics may also comprise further additives known to the person skilled in the art and described in the literature. For example, from O to 15%, preferably from 0 to 10%, of pleochroic dyes and/or chiral dopants can be added. The individual compounds added are employed in concen - 27 trations of from 0.01 to 6%, preferably from 0.1 to 3%. However, the concentration data of the other constituents of the liquid-crystal mixtures, i.e. the liquid-crystalline or mesogenic compounds, are indicated without taking into account the concentration of these additives.

In the present application and in the following examples, the structures of the liquid-crystal compounds are indicated by means of acronyms, the transformation into chemical formulae taking place in accordance with Tables A and B below. All radicals CnH2n+, and CmH2m+, are straight-chain alkyl radicals having n and m C atoms respectively. n and m denote inte gers,preferably1,2,3,4,5,6,7,8,9,10,11 or12,wheren=mornm.

The coding in Table B is self-evident. In Table A, only the acronym for the parent structure is indicated. In individual cases, the acronym for the par- ent structure is followed, separated by a dash, by a code for the substitu ents R', R2, L' and L2: Code for R', R' R2. L'. L2.

R2 L' L2.

nm CnH2n+' CmH2m+' H H nO.m OCnH2n+' CmH2m+' H H nOm CnH2n+. OCmH2m+' H H N CnH2n+, CN H H nN.F CnH2n+. CN F H nN.F.F CnH2n+' CN F F nF CnH2n+ ' F H H nOF OCnH2n+' F H H nF.F CnH2n+' F F H nmF CnH2n+. CmH2m+' F H nOCF3 CnH2n+' OCF3 H H n-Vm CnH2n+' -CH=CHCmH2m+' H H nV-Vm CnH2n±CH=CH-CH=CHCmH2m+' H H Preferred mixture components are given in Tables A and B. - 28

Table A:

L1* L1 R'*L2 R2. R'*{2.R2.

PYP PYRP

R1R2 RR2.

BCH CBC L1

R1{_R2. R1R2*

CCH COP L1

R1{C-CR2 L2*

CPTP

R1Coo<}R2

CP

Rl(COOR2

CCPC L'

R1--{C2H4{ - C-C R2. L2

CEPTP - 29 L' L1

R1*{C H:R2* R1*{)C H L2*R2*

ECCP CECP

L1 L' R1 {>C2NR2 R1 {a R2* 2* 2*

L L

EPCH PCH

L' L1 R1_ L2 R,* - C2H4L2*R2*

PTP BECH L1

R1_(C2H4{>R2* R1-In* L2*

EBCH CPC

R1L2,R2. F C2H4}RZ

B FET

R1 R2 R1*-_

CGG CGU - 30

R1' y,-; R2

CFU

Table B:

F F

CnH2n+1CmH2m+1 CnH2 - XF BCH-n.Fm CFU-n-F 1 5 CnH2n+1{)C2H4CmH2m+, I-nm CnH2n ' F CnH2n F BCH-nF.F BCH-nF.F.F CnH2n+ ' F CmH2m+' CBC-nmF CnH2n+1C2H4{CmH2m 1 ECCP-nm CnH2n+1CH2OCmH2m+1 CCH-n1 Em - 31 CnH2n+1{>COO{}CmH2m+1 OS-nm CnH2n+1{COO - F 1 0 CCZU-n-F CnH2COOiCmH2m+1 CnH2 CH-nm CC-n-V

F F F

CnH2F CnH2n+CO> CGU-n-F CDU-n-F

F F F

CnH2 F CnH2n+ OCHF2 CGG-n-F CDU-n-OD CnH2n+1ocF3 IF CnH20CHF2 CCP- nOCF3 CCP-nOCF2.F

F F

CnH2F CnH2oCF3 CCP-nF.F.F CCP-nOCF3.F - 32

F F

CnH2CF2 F CnH2n+1 it} CF2 F

F F

CCQU-n-F CQCU-n-F CnH2F C,H2F F Dec-U-n-F GPTU-n-F

F F

CnH2COO {IF

F

CZGU-n.F CC-1V.V1 CnH2 CnH2 'F F CC-n-V1 CCTU-n-F CnH2n+1CH2CH2{0cF3 CECGn-OT CnH2n+1{ - CH2CH2{;: OCF3 CECU.n-OT - 33 CnH2n+1 CF2O CmH2m+1 CCQPCn-m CnH2n+1 {I} CHAIN CmH2m+1 CCOC-n-m

F

CnH2n+' iCF2CF2{ CF2O F CWCQU-n-F

Table C:

Table C shows possible dopants which are preferably added to the mixtures according to the invention.

C2Hs-CH-CH2O ON C2H5-CH-CH2} ON CH3 CH3 C 15 CB 15 C6H,3-CH {C5H,, CM 21 a C6H,30 _0 O-CH-C6H13 CH3 CM 33 - 34 CHs C6H13{}CO - }COO-CH-C6H,3 R/S 811 row * C3H7 BAA CH2-CH-C2H5 CH3 CM 44 C6H,, O-CH C8H17O 0-CH { : C2H6 C2H6 CM45 CM47 H3C CH3 CH3 O: C6H,75 H

ON

C3H7 Cl H3

F

R/S 2011 Particular preference is given to mixtures according to the invention which, besides one or more compounds of the formula I according to the inven tion, comprise two, three or more compounds selected from Table B. The following examples are intended to explain the invention without lim iting it. Above and below, percentages denote per cent by weight. All tem peratures are given in degrees Celsius. m.p. denotes melting point and cl.p. = clearing point. Furthermore, C = crystalline state, N = nematic phase, Sm = smectic phase and I = isotropic phase. The data between - 35 these symbols represent the transition temperatures. An denotes optical anisotropy (589 nm, 20 C), and 6 the dielectric anisotropy (1 kHz, 20 C).

The An and 6 values of the compounds according to the invention were obtained by extrapolation from liquid-crystalline mixtures which consisted of 10% of the respective compound according to the invention and 90% of the commercially available liquid-crystal mixture ZLI 4792 (Merck, Darm stadt).

"'Conventional work-up'' means that water is added if necessary, the mix ture is extracted with methylene chloride, diethyl ether or toluene, the phases are separated, the organic phase is dried and evaporated, and the product is purified by distillation under reduced pressure or crystallization and/or chromatography.

Above and below, the following abbreviations are used: DMF dimethylformamide LDA lithium diisopropylamide n-BuLi n-butyllithium RT room temperature (about 20 C) THF tetrahydrofuran - 36 ExamDIe 1 The compound of the following formula

F

is prepared as follows: 3: JS ' 25: \ The synthesis of 2 from cholestanone 1 was carried out in accordance with the procedure of D. Seebach, M. Kolb, Liebigs Ann. Chem. 1977, 811-829.

The synthesis of 3 was carried out by the general method in: P. Kirsch, M. Bremer, A. Taugerbeck, T. Wallmichrath, Angew. Chem. Int. Ed. 2001, 40, 1480-1484: 50 mmol of CF3SO3H were added at -70 C to a solution of mmol of 2 in 300 ml of CH2CI2. The solution was allowed to warm to RT, stirred for 1 h and then re-cooled to -70 C. Then, firstly a solution of - 37 mmol of 3,4,5-trifluorophenol and 80 mmol of NEt3 in 100 ml of CH2C12 was added dropwise, followed by 250 mmol of NEt33HF and 250 mmol of bromine in 50 ml of CH2CI2. The mixture was allowed to come to RT, poured onto ice, neutralized using 2N NaOH and extracted with CH2C12.

Conventional work-up was followed by chromatography (silica gel; nheptane) and recrystallization from heptane. Yield: 63% of 3, colourless crystals.

AS = +7.6 An = +0.0312 C 102 N 149.01 The following compounds according to the invention are obtained analo gously using the corresponding precursors: Examoles 2 - 39 20:: t' H 'CF2y

Examples L' L2 Y

2 H H F 3 H F F 4 H H Cl H F Cl 6 F F Cl 7 H H Br 8 H F Br 9 F F Br 10 H H ON 11 H F ON - 38

Examples L' L2 Y

12 F F CN 13 H H CH3 14 H F CH3 F F CH3 16 H H C2H5 17 H F C2Hs 18 F F C2H5 19 H H C3H7 H F C3H7 21 F F C3H7 22 H H C4Hg 23 H F C4He 24 F F C4Hg H H C5H 26 H F C5H' 27 F F CsH1l 28 H H CsH13 29 H F C6H13 F F C6H13 31 H H CF3 32 H F CF3 33 F F CF3 34 H H OCF3 H F OCF3 36 F F OCF3 37 H H OCHF2 38 H F OCHF2 39 F F OCHF2 - 39 Data for CH3 < 'CF2OoCF3

(Example 35):

s = +7.8 An = +0.0426 C94N 175.11 The following compounds according to the invention are obtained analo gously to Example 1 using the corresponding precursors: ExamoIes 40 - 111 H CF, Examples L' L2 L3 L4 Y

H H H H F

41 F H H H F 42 F F H H F 43 F H F H F 44 F F F H F

F F F F F

46 H H H H Cl 47 F H H H Cl 48 F F H H Cl 49 F H F H Cl 50 F F F H Cl 51 F F F F Cl - 40 Examples L1 L2 L3 L4 Y 52 H H H H CN 53 F H H H CN 54 F F H H CN

F H F H CN

56 F F F H CN 57 F F F F CN 58 H H H H CH3 59 F H H H CH3 F F H H CH3 61 F H F H CH3 62 F F F H CH3 63 F F F F CH3 64 H H H H C2H5 F H H H C2H5 66 F F H H C2H5 67 F H F H C2H5 68 F F F H C2H5 69 F F F F C2H5 H H H H C3H7 71 F H H H C3H7 72 F F H H C3H7 73 F H F H C3H7 74 F F F H C3H7 F F F F C3H7 76 H H H H C4Hg 77 F H H H C4Hg 78 F F H H C4Hg 79 F H F H C4Hg F F F H C4Hg 81 F F F F C4Hg 82 H H H H C5H 83 F H H H C5H

Examples L1 2 3 4 y

84 F F H H C5H'' F H F H C5H'' 86 F F F H C5H', 87 F F F F C5H', 88 H H H H C6H'3 89 F H H H C6H'3 F F H H C6H'3 91 F H F H C6H'3 92 F F F H C6H'3 93 F F F F C6H'3 94 H H H H CF3 F H H H CF3 96 F F H H CF3 97 F H F H CF3 98 F F F H CF3 99 F F F F CF3 100 H H H H OCF3 101 F H H H OCF3 102 F F H H OCF3 103 F H F H OCF3 104 F F F H OCF3 105 F F F F OCF3 106 H H H H OCHF 107 F H H H OCHF 108 F F H H OCHF 109 F H F H OCHF

F F F H OCHF

111 F F F F OCHF - 42

ExamPles 112- 138

The following compounds according to the invention are obtained analo gously to the process of Example 1 using the corresponding precursors (in each case the corresponding cyclohexyl-substituted phenol of the formula

HO_R

L2 instead of 3,4,5-trifluorophenol): H 'CF2R

Examples L, L2 R

112 H H CH3 1 13 H F CH3 114 F F CH3 H H C2H5 116 H F C2H5 117 F F C2H5 1 18 H H C3H7 119 H F C3H7 F F C3H7 121 H H C4Hg 122 H F C4Hg 123 F F C4Hg 124 H H C5H H F C5H 126 F F C5H 127 H H C6H 128 H F C6H - 43

Examples L1 L2 R

129 F F C6H'3 H H CF3 131 H F CF3 132 F F CF3 133 H H OCF3 134 H F OCF3 F F OCF3 136 H H OCHF2 137 H F OCHF2 138 F F OCHF2 Experimental data for 15, CH, H "CF2 4 (Example 118): 's = + 2.3 An = +0.0627 C 112 SmA 226 N >300 1 - 44

Example 139 Be

1 0 t, OB(OH)2 -On-F

F F F 5

4 was prepared analogously to the preparation of 3 in Example 1 using 4-bromophenol.

A mixture of 30 mmol of 4, 30 mmol of 5, 2.0 mmol of Pd(PPh3)4, 300 ml of toluene and 300 ml of sodium borate buffer pH 9 was stirred at 80 C for 18 h. The solution was poured into 500 ml of 0.1 N HCI, extracted three times with CH2CI2, dried over Na2SO4 and evaporated to dryness in a rotary evaporator. The crude product was chromatographed (silica gel; n- heptane) and crystallized from n-heptane. Yield: 67% of 6, colourless crystals.

& = -1.2 An = +0.1160 C 105 SmA 211 N 312.81 The following compounds according to the invention are obtained analo gously to Example 139 using the corresponding precursors:

- - 45

Examoles 140- 183 CH3 <'CF R Examples L' L2 L3 L4 R 140 F F H H CH3 141 F F F F CH3 142 H H F F CH3 143 F F H H OCH3 144 F F F F OCH3 145 H H F F OCH3 146 F F H H C2H5 147 F F F F C2H5 148 H H F F C2H5 149 F F F F OC2Hs H H F F OC2H5 151 F F H H C3H7 152 F F F F C3H7 153 H H F F C3H7 154 F F H H OC3H7 F F F F OC3H7 156 H H F F OC3H7 157 F F H H C4He 158 F F F F C4He 159 H H F F C4H' F F H H OC4Hg 161 F F F F OC4Hg 162 H H F F OC4He 163 H H H H CsH'' 164 F F H H C5H'' - 46 Examples L' 2 L3 L4 R F F F F C5H' 166 H H F F OC5H'' 167 F F F H OC5H'' 168 F F H H OC5H'' 169 F F F F C6H'3 H H F F C6H'3 171 F F H H C6H'3 172 F F H H OC6H'3 173 F F F F OC6H'3 174 H H F F OC6H'3 H H H H CF3 176 F F H H CF3 177 F F F F CF3 178 H H F F OCF3 179 F H H H OCF3 F F H H OCF3 181 F F H H oCHF2 182 F F F F OCHF2 183 H H F F OCHF2 - 47 ExamDIes 184 - 223: The following compounds according to the invention are obtained analo- gously to scheme 4 using the corresponding precursors: CH3 <t CH 0 5

H F F F L2

Examples L1 c2 c3 4 5 6 y 184 H H H H H H F

F H H H H H F

186 F F H H H H F 187 F H F H H H F 188 F F F H H H F 189 F F F H F H F 190 F F F F F H F 191 F F F F F F F 192 H H H H H H Cl 193 F H H H H H Cl 194 F F H H H H Cl 195 F H F H H H Cl 196 F F F H H H Cl 197 F F F H F H Cl 198 F F F F F H Cl 199 F F F F F F Cl H H H H H H CF3 - 48 Examples L' L2 L3 L4 L5 6 y 201 F H H H H H CF3 202 F F H H H H CF3 203 F H F H H H CF3 204 F F F H H H CF3 205 F. F F H F H CF3 206 F F F F F H CF3 207 F F F F F F CF3 208 H H H H H H OCF3 209 F H H H H H OCF3 210 F F H H H H OCF3 211 F H F H H H OCF3 212 F F F H H H OCF3 213 F F F H F H OCF3 214 F F F F F H OCF3 215 F F F F F F OCF3 216 H H H H H H OCHF 217 F H H H H H OCHF 218 F F H H H H OCHF 219 F H F H H H OCHF 220 F F F H H H OCHF 221 F F F H F H OCHF 222 F F F F F H OCHF 223 F F F F F F OCHF - 49 Examole 224 The compound of the following formula '4 <

F H

is prepared as follows: H3C i\-a< H3C - 0 c Fit -< 8 was synthesised from the cholestanone derivative 7 in accordance with the procedure of D. Seebach, M. Kolb, Liebigs Ann. Chem. 1977, 811-829.

The synthesis of 9 is carried out by the general method in: P. Kirsch, M. Bremer, A. Taugerbeck, T. Wallmichrath, Angew. Chem. Int. Ed. 2001, 40, 1480-1484: 50 mmol of CF3SO3H are added at -70 C to a solution of mmol of 8 in 300 ml of CH2CI2. The solution is allowed to warm to RT, stirred for 1 h and then re-cooled to -70 C. Then, firstly a solution of - 50 mmol of 3,4,5-trifluorophenol and 80 mmol of NEt3 in 100 ml of CH2CI2 is added dropwise, followed by 250 mmol of NEt33HF and 250 mmol of bromine in 50 ml of CH2CI2. The mixture is allowed to come to RT, poured onto ice, neutralised using 2N NaOH and extracted with CH2CI2. Conven tional workup is followed by chromatography (silica gel; n-heptane) and recrystallisation from heptane, giving 9 as colourless crystals.

The following compounds according to the invention are obtained analo gously using the corresponding precursors: Examoles 225 - 261

- H | H

'CF2Y

Examples L' L2 Y

225 H H F 226 H F F 227 H H Cl 228 H F Cl 229 F F Cl 230 H H Br 231 H F Br 232 F F Br 233 H H CN 234 H F CN 235 F F CN 236 H H CH3 237 H F CH3 238 F F CH3 239 H H C2H5 - 51

Examples L' L2 y

240 H F C2H5 241 F F C2H5 242 H H C3H7 243 H F C3H7 244 F F C3H7 245 H H C4Hg 246 H F C4H 247 F F C4Hg 248 H H C5H 249 H F C5H 250 F F C5H11 251 H H C6H13 252 H F C6H13 253 F F C6H13 254 H H CF3 255 H F CF 256 F F CF3 257 H H OCF3 258 H F OCF3 259 F F OCF3 260 H H OCHF2 261 H F OCHF2 262 F F OCHF2 The following compounds according to the invention are obtained analo gously to Example 224 using the corresponding precursors: - 52 ExamoIes 263 - 334 s K- Examples Li L2 3 c4 y 263 H H H H F 264 F H H H F 265 F F H H F 266 F H F H F 267 F F F H F 268 F F F F F 269 H H H H Cl 270 F H H H Cl 271 F F H H Cl 272 F H F H Cl 273 F F F H Cl 274 F F F F Cl 275 H H H H CN 276 F H H H CN 277 F F H H CN 278 F H F H CN 279 F F F H CN 280 F F F F CN 281 H H H H CH 282 F H H H CH 283 F F H H CH 284 F H F H CH 285 F F F H CH 286 F F F F CH Examples L1 c2 L3 L4 Y 287 H H H H C2H5 288 F H H H C2H5 289 F F H H C2H5 290 F H F H C2H5 291 F F F H C2H5 292 F F F F C2H5 293 H H H H C3H7 294 F H H H C3H7 295 F F H H C3H7 296 F H F H C3H7 297 F F F H C3H7 298 F F F F C3H7 299 H H H H C4Hg 300 F H H H C4Hg 301 F F H H C4Hg 302 F H F H C4Hg 303 F F F H C4Hg 304 F F F F C4Hg 305 H H H H C5H'' 306 F H H H C5H'' 307 F F H H C5H,' 308 F H F H C5H'' 309 F F F H C5H'' 310 F F F F C5H'' 311 H H H H C6H'3 312 F H H H C6H.3 313 F F H H C6H'3 314 F H F H C6H'3 315 F F F H C6H'3 316 F F F F C6H'3 317 H H H H CF3 318 F H H H CF3 - 54 Examples L' L2 L3 L4 Y

-

319 F F H H CF3 320 F H F H CF3 321 F F F H CF3 322 F F F F CF3 323 H H H H OCF3 324 F H H H OCF3 325 F F H H OCF3 326 F H F H OCF3 327 F F F H OCF3 328 F F F F OCF3 329 H H H H OCHF 330 F H H H OCHF 331 F F H H OCHF 332 F H F H OCHF 333 F F F H OCHF 334 F F F F OCHF ExamoIes 335 - 361 The following compounds according to the invention are obtained analo gously to the process of Example 224 using the corresponding precursors (in each case the corresponding cyclohexyl-substituted phenol of the for

HO R

mula L2 instead of 3,4,5-trifluorophenol): > -CF2R c2 -

Examples L' L2 R

335 H H CH3 336 H F CH3 337 F F CH3 338 H H C2H5 339 H F C2H5 340 F F C2H5 341 H H C3H7 342 H F C3H7 343 F F C3H7 344 H H C4Hg 345 H F C4Hg 346 F F C4Hg 347 H H C5H11 348 H F C5H'' 349 F F C5H'' 350 H H C6H'3 351 H F C6H'3 352 F F C6H'3 353 H H CF3 354 H F CF3 355 F F CF3 356 H H OCF3 357 H F OCF3 358 F F OCF3 359 H H OCHF2 360 H F OCHF2 361 F F OCHF2 - 56

Example 362 -<

F n

OB(OH)2 O:F F F 11 s is prepared analogously to the preparation of 9 in Example 224 using 4-bromophenol.

A mixture of 30 mmol of 10, 30 mmol of 5, 2.0 mmol of Pd(PPh3h, 300 ml of toluene and 300 ml of sodium borate buffer pH 9 is stirred at 80 C for 18 h. The solution is poured into 500 ml of 0.1N HCI, extracted three times with CH2CI2, dried over Na2SO4 and evaporated to dryness in a rotary evaporator. The crude product is chromatographed (silica gel; n-heptane) and crystallized from n-heptane, giving 11 as colourless crystals.

The following compounds according to the invention are obtained analogously to Example 362 using the corresponding precursors: ExamDIes 363 406 cF2R - 57 Examples L' L2 L3 L4 R

-

363 F F H H h3 364 F F F F CH3 365 H H F F CH3 366 F F H H OCH3 367 F F F F OCH3 368 H H F F OCH3 369 F F H H C2H5 370 F F F F C2H5 371 H H F F C2H5 372 F F F F OC2H 373 H H F F OCzH5 374 F F H H C3H7 375 F F F F C3H7 376 H H F F C3H7 377 F F H H OC3H 378 F F F F OC3H 379 H H F F OC3H 380 F F H H C4Hg 381 F F F F C4Hg 382 H H F F C4Hg 383 F F H H OC4H 384 F F F F OC4H 385 H H F F OC4H 386 H H H H C5H 387 F F H H C5H1 388 F F F F C5H1, 389 H H F F OC5H 390 F F F H OC5H 391 F F H H OC5H 392 F F F F CsH13 393 H H F F CsH13 - 58 Examples L' L2 L3 L4 R 394 F F H H C6H13 395 F F H H OC6H,3 396 F F F F OC6H'3 397 H H F F OC6H'3 398 H H H H CF3 399 F F H H CF3 400 F F F F CF3 401 H H F F OCF3 402 F H H H OCF3 403 F F H H OCF3 404 F F H H OCHF2 405 F F F F OCHF2 406 H H F F OCHF2

Examples 407 - 446:

The following compounds according to the invention are obtained analo gously to Scheme 4 using the corresponding precursors: rZ WH F F F L2 - 59 Examples L' L2 L3 L4 Ls L6 Y

-

407 H H H H H H F 408 F H H H H H F 409 F F H H H H F 410 F H F H H H F 411 F F F H H H F 412 F F F H F H F 413 F F F F F H F 414 F F F F F F F 415 H H H H H H Cl 416 F H H H H H Cl 417 F F H H H H Cl 418 F H F H H H Cl 419 F F F H H H Cl 420 F F F H F H Cl 421 F F F F F H Cl 422 F F F F F F Cl 423 H H H H H H CF3 424 F H H H H H CF3 425 F F H H H H CF3 426 F H F H H H CF3 427 F F F H H H CF3 428 F F F H F H CF3 429 F F F F F H CF3 430 F F F F F F CF3 431 H H H H H H OCF3 432 F H H H H H OCF3 433 F F H H H H OCF3 434 F H F H H H OCF3 435 F F F H H H OCF3 436 F F F H F H OCF3 437 F F F F F H OCF3 438 F F F F F F OCF3 - 60 Examples L1 L2 L3 L4 Ls Ls Y 439 H H H H H H OCHF2 440 F H H H H H OCHF2 441 F F H H H H OCHF2 442 F H F H H H OCHF2 443 F F F H H H OCHF2 444 F F F H F H OCHF2 445 F F F F F H OCHF2 446 F F F F F F OCHF2 - 61

Mixture Example 1

* A liquid-crystal mixture comprising BCH-3F.F 10.81 % BCH-5F.F 9.01 % ECCP30CF3 4.51 % ECCP-50CF3 4.51 % CBC-33F 1.80% CBC-53F 1.80% CBC-55F 1.80% PCH-6F 7.21 % PCH-7F 5.41 % CCP-20CF3 7.21 % CCP-30CF3 10.81 % CCP40CF3 6. 31 % CCP-50CF3 9.91 % PCH-5F 9.01 % Compound 3 of Example 1 9.88% has the following properties: clearing point: +94.9 C MUG: +5.6 An: +0.0905

Mixture Example 2

A liquid-crystal mixture comprising BCH-3F.F 10.81 % BCH-5F.F 9.01 % ECCP30CF3 4.50% ECCP-50CF3 4.50% CBC-33F 1.80% CBC-53F 1.80% CBC-55F 1.80% PCH-6F 7.21% PCH-7F 5.40% CCP-20CF3 7.21% CCP-30CF3 10.81% CCP40CF3 6.31% CCP-50CF3 9.91% PCH-5F 9.01% Compound of Example 35 9.92% has the following properties: clearing point: +96.8 C As: 55.6 An: '0.0916 Mixture Examole 3 A liquid-crystal mixture comprising BCH-3F.F 10.80% BCH- 5F.F 9.00% ECCP-30CF3 4.50% ECCP-50CF3 4.50% CBC-33F 1.80% CBC-53F 1.80% CBC-55F 1.80% PCH-6F 7.20% PCH-7F 540% CCP-20CF3 7.20% CCP-30CF3 10.80% CCP^OCF3 6.30% CCP-50CF3 9.90% PCH-5F 9.00% Compound of Example 139 9.98% - 63 has the following properties: clearing point: +111.6 C DIG: +4.7 An: +0.0989 a

Mixture Example 4

A liquid-crystal mixture comprising BCH-3F.F 10.81 % BCH-5F.F 9.01 % ECCP30CF3 4.50% ECCP-50CF3 4.50% CBC-33F 1.80% CBC-53F 1.80% CBC-55F 1.80% PCH-6F 7.21 % PCH-7F 5.40 /O CCP-20CF3 7.21 % CCP-30CF3 10.81 % CCP40CF3 6.31 % CCP-50CF3 9.91 % PCH-5F 9.01 % Compound of Example 118 9. 92% has the following properties: clearing point: +111.6 C DOG: +5.0 An: + 0.0936 - 64

Claims (16)

1. Claims 1. A cholestanyl derivative of the formula I CH3 A, H CF2O MG in

   which -MG stands for-[-Ai4-Z'3-]c-[-A'3-Z12-]b-[-A'2-Z''-]a-A'1-R11; 1 5 where R'' denotes H. -B(OH)2, -B(ORX)(ORY), halogen, ON, SF5, NCS or a linear or branched, optionally chiral alkyl radical having from 1 to 15 C atoms which is unsubstituted or mono- or poly substituted by ON, F. Cl, Br and/or 1, where, in addition, one or more CH2 groups of the alkyl radical may each, independ ently of one another, be replaced by -O-, -S-, -SO2-, -CO-, -coo-, -o-co-, -o-co-o-, -CH=CH-, -CH=CF-, -CF=CF- or -C-(; in such a way that heteroatoms in the chain are not linked directly to one another, where Rx and RY either, independently of one another, denote an alkanyl or alkenyl radical having up to 8 carbon atoms or together form an alkylene bridge having up to 8 carbon atoms in the bridge which is optionally substituted by one or more C'.4-alkanyl radicals; A'', A'2, A'3 and A'4 each, independently of one another, denote trans-1,4-cyclohexylene, in which, in addition, one or more non- adjacent CH2 groups may be replaced by-O and/or -S-, 1,4-phenylene, in which one or two CH groups may be replaced by N and in which, in addition, one or more - 65 H atoms may be replaced by F. Cl, CF3, ON, CHa, OCH3, OCHF2 and/or OCF3, or a radical from the group consisting of 1,4-bicydo[2. 2.2]octylene, piperidine-1,4iyl, naphtha lene-2,dlyl, decahydronaphthalene-2,6iyl and 1,2,3,4 tetrahydronaphthalene-2,6-dlyl, in which, in addition, one or more H atoms may be replaced by F. Cl, CF3, ON, CH3, OCH3, OCHF2 and/or OCF3; Z11 Z12 and Z'3 each, independently of one another, denote WHO-, ACHE, -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CF2CF=, CH2CF2-, F2CH2-, -CH2CH2-, -CH=CH-, -CH=CF-,-CF=CH-, -CF=CF-, -CF=CF-CO O-, -O-CO-C F=C F-, or a single bond; a, b and c each, independently of one another, denote O or 1; and n denotes O or 1.
2. 2. A cholestanyl derivative as claimed in claim 1, wherein R11 denotes F. Cl, Br, I, SO2CF3, cyano or a straighthain or branched alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoroalkenyl radical having up to 8 carbon atoms.
3. 3. A cholestanyl derivative as claimed in claim 1 or 2, wherein A", Air, A'3 and A'4 each, independently of one another, stand for - 66

   F

   {} F F. 1 8 <- A}' {/ or I}.
4. 4. A cholestanyl derivative as claimed in any of the preceding claims wherein Z11, z2 and z13 each, independently of one another, denote a sin glebond,F2,-OCF2-,-CO^or-O.
5. 5. A cholestanyl derivative as claimed in any one of the preceding claims, wherein A'2, A'3 and A'4 each independently of one another, stand for {} 4 )=\ F. F' or
6. 6. A cholestanyl derivative as claimed in any of the preceding claims, wherein a+b+c is 0, 1 or 2.
7. 7. A cholestanyl derivative as claimed in any one of the preceding claims, wherein All s$andsfor I, , }, {I or I; and - 67 Ri' denotes a straighthain or branched alkanyl, fluoroalkanyl, alkoxy, fluoroalkoxy, alkenyl or fluoroalkenyl radical having up -to 8-carbon-atoms.
8. 8. A cholestanyl derivative as claimed in any one of the preceding claims 1 to 6, wherein A stands for 4, or;and R., denotes F. a, Or or a straightchain alkanyl, 11uoroallcanyl, alkoxy, fluoroalkoxy, allonym or nits radical having up 8 carbon atoms.
9. 9. A cholestanyl derivative as claimed in any of the preceding claims, wherein n is 0.
10. 10. A cholestanyl derivative as claimed in claim 1, substantially as hereinbefore described with reference to Examples 1 to 446.
11. 11. Use of a cholestanyl derivative as claimed in any of the preceding claims as a component in a liquid-crystalline medium.
12. 12. Liquid-crystalline medium having at least two liquidrystalline components, which comprises at least one cholestanyl derivative as claimed in any one of claims 1 to 10.
13. 13. Liquid crystalline medium substantially as hereinbefore described with reference to Mixture Examples 1 to 4. - 68
14. 14. Liquid-crystal display element, which comprises a liquid-crystalline medium according to claim 12 or 13.

    s
15. 15. Reflective or transflective liquid-crystal display element, which comprises, as dielectric, a liquid-crystalline medium according to claim 12 or 13.
16. 16. Electro-optical display element, characterized in that it contains, as dielectric, a liquid-crystalline medium according to claim 12.