DE4344422B4 - Pyri (mi) din derivatives and liquid crystalline medium - Google Patents

Abstract

R einen unsubstituierten oder einen einfach durch CN, Halogen oder CF₃ substituierten Alkyl- oder Alkenylrest mit bis zu 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH₂-Gruppen jeweils unabhängig voneinander durch -O-, -CO-, -CO-O-, -O-CO oder -O-CO-O- so ersetzt sein können, daß O-Atome nicht direkt miteinander verknüpft sind,

(a) trans-1,4-Cyclohexylenrest, worin auch eine oder mehrere nicht benachbarte CH₂-Gruppen durch -O- und/oder -S- ersetzt sein können,
(b) 1,4-Phenylenrest, worin auch eine oder zwei CH-Gruppen durch N ersetzt sein können,
(c) Rest aus der Gruppe 1,4-Cyclohexylen, 1,4-Bicyclo[2.2.2]octylen, Piperidin-1,4-diyl, Naphthalin-2,6-diyl, Decahydronaphthalin-2,6-diyl und 1,2,3,4-Tetrahydronaphthalin-2,6-diyl,
wobei die Reste (a) und (b) durch ein oder zwei Fluor substituiert sein können,
X F, Cl, CN oder Q-Y, wobei
Q -O-, -S- oder eine Einfachbindung
Y ein...The present invention relates to pyri (mi) din derivatives of the formula I in which

R is an unsubstituted or monosubstituted by CN, halogen or CF ₃ alkyl or alkenyl radical having up to 15 carbon atoms, wherein in these radicals also one or more CH ₂ groups each independently of one another by -O-, -CO-, -CO-O-, -O-CO or -O-CO-O- may be replaced so that O atoms are not directly linked to each other,

(a) trans-1,4-cyclohexylene radical, in which also one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S-,
(b) 1,4-phenylene radical, in which also one or two CH groups may be replaced by N,
(c) radical from the group consisting of 1,4-cyclohexylene, 1,4-bicyclo [2.2.2] octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1 , 2,3,4-tetrahydronaphthalene-2,6-diyl,
where the radicals (a) and (b) can be substituted by one or two fluorine,
X is F, Cl, CN or QY, where
Q is -O-, -S- or a single bond
Y a ...

Description

worin
R einen unsubstituierten oder einen einfach durch CN, Halogen oder CF₃ substituierten Alkyl- oder Alkenylrest mit bis zu 15 C-Atomen, wobei in diesen Resten auch eine oder mehrere CH₂-Gruppen jeweils unabhängig voneinander durch -O-, -CO-, -CO-O-, -O-CO oder -O-CO-O- so ersetzt sein können, daß O-Atome nicht direkt miteinander verknüpft sind,

• 
  (a) trans-1,4-Cyclohexylenrest, worin auch eine oder mehrerenicht benachbarte CH₂-Gruppen durch -O- und/oder -S- ersetzt sein können,
• (b) 1,4-Phenylenrest, worin auch eine oder zwei CH-Gruppen durch N ersetzt sein können,
• (c) Rest aus der Gruppe 1,4-Cyclohexylen, 1,4-Bicyclo[2.2.2]octylen, Piperidin-1,4-diyl, Naphthalin-2,6-diyl, Decahydronaphthalin-2,6-diyl und 1,2,3,4-Tetrahydronaphthalin-2,6-diyl,

wobei die Reste (a) und (b) durch ein oder zwei Fluor substituiert sein können,
X F, Cl, CN oder Q-Y, wobei
Q -O-, -S- oder eine Einfachbindung
Y ein oder mehrfach halogeniertes Alkyl oder Alkenyl mit bis zu 10 C-Atomen ist,
Z N oder CH
L¹ und L² jeweils unabhängig voneinander H oder F, und
m 1 oder 2
bedeuten.The present invention relates to pyri (mi) din derivatives of the formula I,

wherein
R is an unsubstituted or monosubstituted by CN, halogen or CF ₃ alkyl or alkenyl radical having up to 15 carbon atoms, wherein in these radicals also one or more CH ₂ groups each independently of one another by -O-, -CO-, -CO-O-, -O-CO or -O-CO-O- may be replaced so that O atoms are not directly linked to each other,

• 
  (a) trans-1,4-cyclohexylene radical, in which also one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S-,
• (b) 1,4-phenylene radical, in which also one or two CH groups may be replaced by N,
• (c) radical from the group consisting of 1,4-cyclohexylene, 1,4-bicyclo [2.2.2] octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1 , 2,3,4-tetrahydronaphthalene-2,6-diyl,

where the radicals (a) and (b) can be substituted by one or two fluorine,
X is F, Cl, CN or QY, where
Q is -O-, -S- or a single bond
Y is mono- or polyhalogenated alkyl or alkenyl having up to 10 carbon atoms,
ZN or CH
L ¹ and L ^{2 are} each independently H or F, and
m 1 or 2
mean.

The The invention further relates to the use of these compounds as components of liquid crystalline Media.

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

R¹ = Alkyl; R² = Alkyl, Alkoxy oder Chlor genannt.The compounds of the formula I are partially of the very general formula in the EP 0 306 505 detected. There, however, only pyri (mi) din derivatives of the formulas

R ¹ = alkyl; R ² = alkyl, alkoxy or chlorine called.

In the patent applications EP 0409634 A2 , JP 05/065485 A2 and DE 4331594 A1 are disclosed pyridine and pyrimidine derivatives having alkyl and alkoxy substituents in which the substituent is placed as in formula I next to the nitrogen atom.

Of the The invention therefore an object of the invention, new stable liquid crystalline or to find mesogenic compounds which are components of liquid-crystalline Media are suitable and in particular at the same time a comparatively low viscosity possess and a relatively high dielectric anisotropy.

It has now been found that compounds of the formula I as components of liquid-crystalline Media excellent are suitable. In particular she over comparatively low viscosities. Leave with their help Stable liquid crystalline Media with wide mesophase range and advantageous values for the optical and dielectric anisotropy. These media also have a very good low temperature behavior.

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

The compounds of the formula I preferably comprise the compounds of the formulas I1-I18

If X represents a halogenated alkyl, alkoxy or alkenyl radical, this may be straight-chain or branched. Preferably he straight-chain and has 1,2,3,4,5,6 or 7 C-atoms; in the case of the alkenyl radical 2,3,4,5,6 or 7 C atoms.

X is preferably F, Cl, CN, OC _n F _{2n + 1} , C _n F _{2n + 1} , O (CH ₂ ) _n -CF ₃ , O (CH ₂ ) n CF ₂ H, O (CH ₂ ) _n -CHF ₂ , (CH ₂ ) _n -CF ₃ , (CH ₂ ) _n -CF ₂ H, (CH ₂ ) _n -CHF ₂ , (CH ₂ ) _n -CH = CF ₂ , (CH ₂ ) _n -CF = CF ₂ , (CH ₂ ) _n -CH = CFH, SC _n F _{2n + 1} , S (CH ₂ ) _n CF ₃ , O (CH ₂ ) _n -CCl ₂ , (CH ₂ ) _n -CH = CCl ₂ or ( CF ₂ ) _n -CF ₂ H, where n is 0 to 7. Particular preference is given to pyridine (III) din derivatives of the formula I in which X, F, Cl, CN, OCF ₃ or OCH ₂ CF ₃ .

If R represents an alkyl radical and / or an alkoxy radical, this may straight-chain or branched. Preferably, it is straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and therefore preferably Ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, Pentoxy, hexoxy or heptoxy, furthermore methyl, octyl, nonyl, decyl, Undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, Nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

oxaalkyl preferably denotes straight-chain 2-oxapropyl (= methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxo-octyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R is an alkyl radical in which a CH ₂ group is replaced by -CH = CH-, this may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. It therefore 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 by -CO-, these are preferably adjacent. Thus, these include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. Preferably, these are straight-chain and have 2 to 6 carbon atoms.

she therefore especially acetyloxy, propionyloxy, butyryloxy, Pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, Butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, Ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, Methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, Butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) -butyl.

If R is an alkyl radical in which a CH ₂ group is replaced by unsubstituted or substituted -CH-CH- and an adjacent CH ₂ group by CO or CO-O or O-CO-, this may be straight-chain or branched , Preferably, it is straight-chain and has 4 to 13 carbon atoms. It therefore particularly means acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxy-butyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl, 9-methacryloyloxynonyl.

If R 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 radical in which two or more CH ₂ groups have been replaced by -O- and / or -CO-O-, this may be straight-chain or branched. Preferably, it is branched and has 3 to 12 carbon atoms. It therefore particularly denotes bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxyhexyl, 7,7-biscarboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxydecyl, 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.

If R is an alkyl or at least monosubstituted by halogen Alkenyl means, this radical is preferably straight-chain and halogen is preferably F or Cl. With multiple substitution Halogen is preferably F. The resulting radicals also include perfluorinated radicals. For single substitution, the fluoro or chlorine substituent in any position, but preferably in the ω position.

links of formulas I with branched wing groups R can occasionally because of a better solubility in the usual liquid crystalline Base materials of importance, but especially as a chiral Dopants when they are optically active. Smectic compounds These types are suitable as components for ferroelectric materials.

branched Groups of this kind usually contain no more than one chain branch. Preferred branched radicals R are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 1-methylheptoxy.

links the formula I, the over for polycondensations suitable wing groups R are suitable to represent liquid crystalline Polycondensates.

formula I included both the racemates of these compounds and the optical antipodes as well as their mixtures.

links of the formula I with SA phases are suitable, for example, for thermal addressed displays.

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

In the compounds of the formula I, those stereoisomers are preferred, in which the cyclohexane ring is trans-1,4-disubstituted.

The Compounds of the formula I are prepared by methods known per se as described in the literature (e.g., in the standard works as Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart) are described, under reaction conditions, for those mentioned Reactions are known and suitable.

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

The Starting materials can if desired also be formed in situ, such that they are removed from the reaction mixture not isolated, but immediately further to the compounds of the formula I implements.

The compounds of the invention can be z. B. easy to prepare according to the following reaction scheme. Scheme 1

The preparation of some particularly preferred compounds is shown in Scheme 2. Scheme 2

The liquid crystalline according to the invention Media preferably contain one or more compounds of the invention as further constituents 2 to 40, in particular 4 to 30 components. All more preferably, these media contain one or more besides Compounds of the invention 7 to 25 components. These other ingredients are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, especially substances from the classes of the azoxybenzenes, Benzylidenaniline, Biphenyls, terphenyls, phenyl or cyclohexyl benzoates, cyclohexane-carboxylic acid-phenyl or cyclohexyl esters, phenyl or cyclohexyl esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters cyclohexylcyclohexanecarboxylic acid, Cyclohexylphenylester of benzoic acid, the cyclohexane carboxylic acid, or cyclohexylcyclohexanecarboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, Cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-biscyclohexylbenzenes, 4,4'-Biscyclohexylbiphenyle, Phenyl or cyclohexylpyrimidines, phenyl or cyclohexylpyridines, Phenyl or cyclohexyl dioxanes, phenyl or cyclohexyl-1,3-dithiane, 1,2-diphenylethanes, 1,2-dicyclohexylethanes, 1-phenyl-2-cyclohexylethanes, 1-cyclohexyl-2- (4-phenyl-cyclohexyl) -ethanes, 1-Cyclohexyl-2biphenylylethanes, 1-phenyl-2-cyclohexyl-phenylethanes, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substituted cinnamic acids. The 1,4-phenylene groups in these compounds can also be fluorinated.

The most important compounds which may be used as further constituents of media according to the invention can be characterized by the formulas 1, 2, 3, 4 and 5: R'-LE-R '' 1 R'-L-COO-E-R "2 R'-L-OOC-E-R "3 R'-L-CH ₂ CH ₂ -E-R "4 R'-LC≡CE-R "5

In the formulas 1, 2, 3, 4 and 5, L and E, the same or different could be, each independently each other is a bivalent radical from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc, -Cyc-Cyc, -Pyr-, Di, -G-Phe and -G-Cyc- and their mirror images formed Group, wherein Phe is 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 preferred Cyc, Phe or Phe-Cyc. Preferably, the media of the invention contain one or more components selected from the compounds of Formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group Cyc, Phe and Pyr and at the same time one or more components selected from the compounds of formulas 1, 2, 3, 4 and 5, wherein one of the radicals L and E selected is selected from the group Cyc, Phe and Pyr and the other radical is selected from the group -Phe-Phe, -Phe-Cyc, -Cyc-Cyc, -G-Phe and -G-Cyc-, and optionally one or more components selected from the compounds of formulas 1, 2, 3, 4 and 5, wherein the radicals L and E selected are from the group -Phe-Cyc, -Cyc-Cyc, -G-Phe and -G-Cyc-.

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

In a smaller subgroup of compounds of formulas 1, 2, 3, 4 and 5, other than group B, R '' is -F, -Cl, -NCS or - (O) _i CH ₃ - _{(k + 1)} F _k Cl ₁ , where i is 0 or 1 and k + 1 is 1, 2 or 3; the compounds in which R "has this meaning are designated by the subformulae 1b, 2b, 3b, 4b and 5b. Particular preference is given to those compounds of the subformulae 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ .

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

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

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

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

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

preferred Media can in addition to the compounds of the invention of formula I consist only of group B compounds. Farther preferred are media which, in addition to the compounds of the formula I, Compounds of Group B and 0-20 % Compounds of group A and / or group C.

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

Table A:

Table B:

In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, wherein the transformation into chemical formulas according to following Tables A and B takes place. All radicals C _n H _{2n + 1} and C _m H _{2m + 1} are straight-chain alkyl radicals with n or m C atoms. The coding according to Table B is self-evident. In Table A, only the acronym for the main body is given. In individual cases, a code for the substituents R ¹ , R ² , L ¹ , L ² and L ³ follows separately from the acronym for the main body with a dash:

Table A:

Table B:

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

DMEU

1,3-Dimethyl-2-imidazoldinon

KOT

Kaliumtertiär-butanolat

THF

Tetrahydrofuran

pTsOH

p-Toluolsulfonsäure

"Conventional workup" means: water is optionally added, extracted with dichloromethane, diethyl ether or toluene, separated, the organic phase is dried, evaporated and the product is purified by distillation under reduced pressure or crystallization and / or chromatography. The following abbreviations are used:

DMEU

1,3-dimethyl-2-imidazoldinon

KOT

Potassium tertiary butoxide

THF

tetrahydrofuran

pTsOH

p-toluenesulfonic acid

example 1

Step 1.1

0.18 mol of trimethylsilylacetylene and 0.18 mol of 4-trans- (4-propylcyclohexyl) bromobenzene are dissolved in 120 ml of piperidine and treated in portions with 0.3 g of tetrakis (triphenylphosphine) palladium (0). After addition of 0.15 g of triphenylphosphine and 0.1 g of copper (I) iodide is slowly heated. Measure allowed to reflux for 1.5 h and then poured the suspension to a HCl / ice-water mixture. After extraction with methyl tert. Butyl ether is worked up as usual. Step 1.2

0.18 mol KOH are dissolved in 255 ml of methanol, treated with the product from step 1.1 (0.18 mol) and stirred for 1 h at room temperature. After addition of 30 ml of conc. HCl and 300 ml of H ₂ O is repeatedly treated with methyl tert. Butyl ether extracted and then worked up as usual. Step 1.3

0.06 mol 1- [4- (trans-4-propylcyclohexyl) phenyl] acetylene, 0.06 mol 5-bromo-2-fluoropyrimidine and 40 ml of triethylamine are introduced and stirred. One by one, 0.1 g bis (triphenylphosphine) palladium (II) chloride, 0.05 g of triphenylphosphine and 0.03 g of copper (I) iodide was added. The mixture is stirred for 48 h at room temperature and pours the mixture in 100 ml of ice-water acidified with 2N HCl. After extraction with methyl tert. Butyl ether is worked up as usual. K 113 N 180.3 I, Δe = 20.5; .DELTA.n = .268.

hergestellt:

Analogously, the following compounds of the formula

produced:

Claims (8)

The present invention relates to pyri (mi) din derivatives of the formula I in which

R is an unsubstituted or monosubstituted by CN, halogen or CF ₃ alkyl or alkenyl radical having up to 15 carbon atoms, wherein in these radicals also one or more CH ₂ groups each independently of one another by -O-, -CO-, -CO-O-, -O-CO or -O-CO-O- may be replaced so that O atoms are not directly linked to each other,

(a) trans-1,4-cyclohexylene radical in which also one or more non-adjacent CH ₂ groups can be replaced by -O- and / or -S-, (b) 1,4-phenylene radical, in which also one or two (C) radical from the group consisting of 1,4-cyclohexylene, 1,4-bicyclo [2.2.2] octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, Decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, where radicals (a) and (b) may be substituted by one or two fluoro, XF, Cl, CN or QY where Q is -O-, -S- or a single bond Y is mono- or polyhalogenated alkyl or alkenyl having up to 10 C atoms, ZN or CH L ¹ and L ^{2 are} each independently H or F, and m is 1 or 2. Pyrimidine derivatives of the formula

wherein R, X,

L ¹ , L ² and m have the meaning given in claim 1. Pyri (mi) din derivatives according to claim 1, wherein X is F, Cl, OCF ₃ , CF ₃ , CN or OCH ₂ CF ₃ . Pyri (mi) din derivatives according to claim 1, wherein m = 1 is. Pyri (mi) din derivatives according to claims 1 to 4, characterized in that L ¹ and L ^{2 are} fluorine. Pyri (mi) din derivatives according to one of the preceding claims, characterized in that

trans-1,4-cyclohexylene, wherein one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S-, wherein the radical may be substituted by one or two fluorine. Pyrimidine derivatives of the formula I1

wherein R, X, L ¹ and L ^{2 have} the meaning given in claim 1. Use of compounds of the formula I as components liquid-crystalline Media.