JPH1067763A - 1,2,5-thiadiazole derivative and use thereof as component of liquid crystal mixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new colorless and chemically, thermally and optically stable compound capable of forming the liquid crystal mesophase within a temperature range suitable for electrooptical uses. SOLUTION: This 1,2,5-thiadiazole derivative is represented by formula I (Y is a group represented by formula II; R<1> and R<2> are each H, a straight-chain or a branched chain 1-20C alkyl, etc.; M<1> to M<4> are each O, S, CO, CO-O, etc.; A<1> to A<4> are each 1,4-phenylene, etc., in which one or more Hs may be substituted with F, Cl and/or CN; (a) to (f) are each 0 or 1; the sum total of (b) to (e) is 1, 2 or 3), e.g. 3-(6-decanoxy-2-fluoropyrid-3-yl)-4-phenyl-1,2,5- thiadiazole. The compound represented by formula I is obtained by a well-known method. Thereby, the compound is suitable for a ferroelectric liquid crystal display based on the utilization of twisted helix forming effects, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to novel compounds suitable for use in liquid crystal mixtures.

[0002]

2. Description of the Related Art Recently, besides nematic liquid crystals and cholesteric liquid crystals, optically active tilted smectic (ferroelectric) liquid crystals are also used in commercially available display devices.

[0003] Clark and Lagerwall are:
The use of ferroelectric liquid crystal (FLC) in a very thin cell results in a normal TN (twisted nematic)
It has been shown that opto-electrical switching or display elements with a response time 1000 times faster than the cell can be obtained (see, for example, EP-A 0032362).
Because of this property and other favorable properties, such as the possibility of bistable switching and contrast that is almost independent of viewing angle, FLCs are basically very useful in applications such as computer displays. Are suitable.

When FLC is used in an electro-optical or completely optical component, a compound which forms a tilted or orthogonal smectic phase and is itself optically active, or which forms a smectic phase but is itself Require any compound capable of inducing a ferroelectric smectic phase by doping a compound that is not optically active with the optically active compound. Desirable phases are those that are stable over the widest possible temperature range.

[0005] In order to achieve good contrast in the electro-optical component, a uniform plane of the liquid crystal is required.
r) An orientation is required. Good orientation in the S _A and S * _C phases can be achieved, for example, when the phase sequence of the liquid crystal mixture is as follows with decreasing temperature: isotropic → N * → S _A → The first requirement for S * _C is that the pitch of the helix in the N * phase is very large (greater than 10 μm) or more preferably completely complementary (eg, T. Mat).
sumoto, et al. Proc. of the
6th Int. Display Research
Conf. , Japan Display, Sep
t. 30-Oct. 2,1986, Tokyo Japan
an, p. 468-470, M.P. Murakami, e
t al. Ibid., P. 344-347). This means, for example, doping a chiral liquid-crystal mixture with a left-handed helix in the N * phase with one or more optically active dopants inducing a right-handed helix in such an amount that the helix is exactly complemented. Achieved by

[0006] Clark and Lagerwall S
A further requirement for obtaining a uniform planar alignment using the SFLCD (surface stabilized ferroelectric liquid crystal display) effect is that the pitch in the smectic C * phase is significantly larger than the thickness of the display element. (Mol. Cryst. Liq. Cryst. 94 (1
983), 213 and 114 (1984), 15
1). This is achieved, as in the case of cholesteric pitch, by using dopants with helical rotation in opposite directions.

[0007] The optical response time τ (μ
s) is preferably as short as possible, but the rotational viscosity γ (m
Pas), spontaneous polarization Ps (nC / cm ² ), and electric field strength E (V / m), and obeys the following formula: τ ／ γ / Ps · E The electric field strength E is between electrodes in the electro-optical component The ferroelectric display medium must have low viscosity and high spontaneous polarization to achieve a short response time, as determined by distance and applied voltage.

Finally, in addition to thermal, chemical and photochemical stability, a low value of the optical anisotropy Δn and a low value of the positive or preferably negative dielectric anisotropy Δε are required. (Eg, ST Lagerwall, Ferro)
electric Liquid Crystals
for Displays, SID Symposiu
m, Oct. Meeting, 1985, San Di
ego, Ca, USA).

Only when a mixture containing a plurality of components is used, all of these conditions can be satisfied. The base (or matrix) used here is preferably formed from a compound which itself has the desired phase sequence I → N → S _A → S _{C if} possible. Lowering the melting point, increasing the temperature range of the S _C phase and usually the N phase,
Still other components are often added to the mixture to induce optical activity, complement pitch, and balance optical and dielectric anisotropy. However, for example, the rotational viscosity should not be increased if possible.

[0010] Ferroelectric liquid crystal displays are also known as DHF
It can also operate by utilizing the (twisted helix formation) effect or the PSFLCD (Pitch Stabilized Ferroelectric Liquid Crystal Display, also known as the SBF (Short Pitch Bistable Ferroelectric) effect) effect. The DHF effect is described in I. Ostrovski, Advancesi
n Liquid Crystal Research
and Applications, Oxford /
Budapest, 1980, 469ff, and the PSFLCD effect is described in DE-A 39 20 625 and EP-A 0 405 346. To take advantage of these effects, compared to the SSFLCD effect, it is necessary liquid crystal material having a short S _C pitch.

1,3,4-Thiadiazole derivatives for use in ferroelectric liquid crystal mixtures are described, for example, in EP-
A03095514.

However, since the development of ferroelectric liquid crystal mixtures, in particular, can never be considered complete, display manufacturers are interested in a very wide range of components used in the mixtures. This also means that the liquid crystal mixture and the individual components of the display element or cell (eg alignment films)
This is because it is only possible to conclude about the quality of the liquid crystal mixture by the interaction with.

[0013]

The object of the present invention is therefore to provide new compounds which are suitable for improving the characteristic profiles of liquid-crystal mixtures.

[0014]

SUMMARY OF THE INVENTION Surprisingly, it has been found that 1,2,5-thiadiazole derivatives of the formula (I) are particularly suitable for use in liquid-crystal mixtures.

[0015] Accordingly, the present invention relates to compounds of formula ^{(I): R 1 (-M} 1) a (-A 1 -M 2) b (-A 2 -M 3) c -Y (-M 4 - A ³ ) _d (−M ⁵ −A ⁴ ) _e (−M ⁶ ) _f R ² (I) wherein the symbols and subscripts have the following meanings:

Embedded image And R ¹ and R ² are the same or different and are hydrogen or a linear or branched alkyl group having 1 to 20 carbon atoms (whether having or not having an asymmetric carbon atom). is good), the one or more CH ₂ groups where, -O -, - S -, - CO -, - CS -, - CH = C
H-, -C≡C-, -CO-O-, -O-CO-, -O
-CO-O-, cyclopropane-1,2-diyl, -S
_{i (CH 3) 2 -,} 1,4- phenylene, trans-1,
It may be substituted by 4-cyclohexylene or trans-1,3-cyclopentylene, provided that the oxygen and / or sulfur atoms are not directly linked to each other and / or one or more of the alkyl groups -F hydrogen atoms, -Cl, may be substituted with -Br or -OR ^3, or R ^1, is in one of the following groups (or is racemic optically active) Yes:

Embedded image

Embedded image R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are the same or different,
Hydrogen or a linear or branched alkyl group having 1 to 16 carbon atoms, which may or may not have an asymmetric carbon atom, wherein one or more CH _{The two} groups may be substituted with -O- and / or -CH = CH-, provided that the oxygen atoms are not directly bonded to each other and / or one or more hydrogen atoms of the alkyl group are Or R ⁴ and R ⁵ may be taken together when attached to an oxirane, dioxolane, tetrahydrofuran, tetrahydropyran, butyrolactone or valerolactone system. -(CH ₂ ) _4- or-(C
H ₂ ) _5- ; M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶ may be the same or different and are —O—, —S—, —C
O-, -CO-O-, -O-CO-, -O-CO-O
-, -CO-S-, -S-CO-, -CS-O-, -O
-CS-, -S-CS-S-, -O-CS-O-, S-
CO-S -, - CS - , - CH 2 -O -, - O-CH
_{2 -, - CH 2 -S -} , - S-CH 2 -, - CH = CH
-, -C≡C- or a single bond; A ¹ , A ² , A ³ and A ⁴ are the same or different and one or more hydrogen atoms are replaced by F, Cl and / or CN 1,4-phenylene, pyrazine-2,5-diyl in which one or two hydrogen atoms may be substituted with F, Cl and / or CN, one or two hydrogen atoms in F , 2-pyridazine-3,6-diyl optionally substituted with Cl and / or CN, pyridine-2,5-optionally substituted one or more hydrogen atoms with F, Cl and / or CN Diyl, pyrimidine-2,5-diyl, in which one or two hydrogen atoms may be replaced by F, Cl and / or CN, one or two hydrogen atoms replaced by CN and / or CH ₃ Transformers that may be 1,4-cyclohexylene, 1,
3,4-thiadiazole-2,5-diyl, 1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5
-Diyl, wherein one hydrogen atom is F, Cl and / or C
1,3-thiazole-2,4 which may be substituted by N
-Diyl, wherein one hydrogen atom is F, Cl and / or C
1,3-thiazole-2,5 which may be substituted by N
-Diyl, wherein one hydrogen atom is F, Cl and / or C
Thiophene-2,4-diyl optionally substituted with N, thiophen-2,5-diyl optionally substituted with one or two hydrogen atoms by F, Cl and / or CN, piperazine-1 , 4-diyl, piperazine-2,
5-diyl, one or more hydrogen atoms is F, Cl
And / or naphthalene-2,6-diyl optionally substituted with CN, bicyclo [2.2.2] wherein one or more hydrogen atoms may be substituted with F, Cl and / or CN Octane-1,4-diyl, 1,
3-dioxaborinane-2,5-diyl, or a group Y; a, b, c, d, e and f are 0 or 1, and the sum of b, c, d and e is 1, 2 or 3 Can be].

[0016]

DETAILED DESCRIPTION OF THE INVENTION In the pure state, the compounds of the formula (I) are colorless and generally form liquid-crystalline mesophases in a temperature range which is preferably defined for electro-optical use. They are chemically, thermally and light-stable.

Preference is given to compounds of the formula (I) in which the symbols and indices have the following meanings: R ¹ and R ² are the same or different and are hydrogen or straight-chain or branched having 1 to 18 carbon atoms. (Which may or may not have an asymmetric carbon), wherein one or more CH ₂ groups are -O-, -CO-, -O-CO
—, —CO—O—, —CH ＝ CH—, —C≡C—, cyclopropane-1,2-diyl, —Si (CH ₃ ) ₂ — or trans-1,4-cyclohexylene it may be, except oxygen atoms not directly bonded to each other, and / or, one or more of the hydrogen atoms of the alkyl group -F, may be substituted by -Cl or -OR ^3, or R ¹ is any of the following groups (optically active or racemic):

Embedded image R ³ , R ⁴ and R ⁵ are the same or different and are hydrogen or a linear or branched alkyl group having 1 to 12 carbon atoms (whether having or not having an asymmetric carbon atom); is good), wherein one or more CH ₂ groups, -O- and / or -CH = CH- may be substituted with, except oxygen atoms not directly bonded to each other,
And / or one or more hydrogen atoms of the alkyl group may be replaced by -F or -Cl; or R ⁴ and R ⁵ together when bonded to a dioxolane system — (CH ₂ ) ₄ — or — (CH ₂ ) ₅
M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶
Are the same or different, and are -O-, -CO-, -CO-O
-, - O-CO -, - O-CO-O -, - CH 2 -O
—, —O—CH ₂ —, —CH ＝ CH— or a single bond; A ¹ , A ² , A ³ and A ⁴ are the same or different;
1,4-phenylene in which one or more hydrogen atoms may be replaced by F, Cl and / or CN, wherein one or more hydrogen atoms is F, Cl and / or C
Pyridine-2,5-diyl optionally substituted with N,
One or two hydrogen atoms are F, Cl and / or C
Pyrimidine-2,5-diyl optionally substituted by N, wherein one or two hydrogen atoms are CN and / or C
Trans-1,4-cyclohexylene optionally substituted with H ₃ , 1,3-dioxane-2,5-diyl, 1
Naphthalene-2,6-diyl optionally substituted by one or more hydrogen atoms with F, Cl and / or CN, or a group Y; a, b, c, d, e and f
Is 0 or 1, and the sum of b, c, d and e can be 1, 2 or 3.

Very particular preference is given to compounds of the formula (I) in which the symbols and indices have the following meanings: R ¹ and R ² are identical or different and are hydrogen or straight-chain or branched having 1 to 12 carbon atoms. A branched alkyl group (whether or not having an asymmetric carbon), wherein 1
, Two or three CH ₂ groups are —O—, —CO—O
—, —O—CO— or trans-1,4-cyclohexylene, provided that the oxygen atoms are not directly bonded to each other and / or one or more hydrogen atoms of the alkyl group May be substituted with F, or R ¹ is any of the following groups (optically active or racemic):

Embedded image R ³ is in each case the same or different and is hydrogen or a straight-chain alkyl group having 1 to 9 carbon atoms, wherein one or more CH ₂ groups are substituted by —O—. But oxygen atoms are not directly bonded to each other; M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶ may be the same or different and represent —O—, —CO—O—, -CO-,-
CH ₂ —O—, —O—CH ₂ — or a single bond;
A ¹ , A ² , A ³ and A ⁴ are the same or different,
1,4-phenylene in which two or three hydrogen atoms may be substituted by F, pyridine-2,5-diyl, pyrimidine- in which one or two hydrogen atoms may be substituted by F 2,5-diyl, trans-1,4-cyclohexylene in which one or two hydrogen atoms may be replaced by CN and / or CH ₃ , or one or two hydrogen atoms by F A, b, c, d and e are optionally substituted naphthalene-2,6-diyl;
It is 0 or 1, and the sum of b, c, d and e may be 1 or 2.

Novel compounds are described in standard books on organic synthesis (eg, Houben-Weyl, Method).
ender Organischen Chemi
e, Georg-Thieme-Verlag, Stu
(ttgart) can be prepared by methods known per se from the literature.

The preparation is carried out under reaction conditions known and suitable for the reaction. Modifications known per se can be used for this purpose, but are not described in detail here.

If desired, the starting materials are prepared in situ and are immediately further isolated without isolation from the reaction mixture.
Can also be converted into the compound of formula (I).

For example, 1,2,5-thiadiazole is
J. Org. Chem. 1967, 2823, but here SO ₂
Alternatively, it is necessary to use S ₂ Cl ₂ . 1,2,
Although 5-thiadiazole can also be obtained by reacting a phenol with S ₄ N ₄ (Senryoto
(Yakukin 1990, 35, 207), where the explosive nature of S ₄ N ₄ is a problem.

The novel compounds of the formula (I) are preferably
3,4-dibromo-1,2,5-thiadiazole, 3,
4-diiodo-1,2,5-thiadiazole or 3-
Prepared by a process that avoids the use of sulfur compounds as described above, starting from 3,4-dihalo-1,2,5-thiadiazole, such as bromo-4-iodo-1,2,5-thiadiazole.

Such dihalogen compounds are, for example, L
ancaster (D-63165 Muhleim / M
ain, Germany).

These can be reacted with the metal compound of formula (II) by the catalysis of a transition metal, preferably using palladium or nickel or their compounds: R ¹ (-M ¹ ) _a (- A ¹ -M ² ) _b (-A ² -M ³ ) _c -Met (II) wherein R ¹ , M ¹ , M ² , A ¹ , A ² , a and b are represented by the formula (I) M ³ is a single bond; c is 1; and Met is Li, Na, K, Z
n (X), B (X) ₂ , AlX ₂ , Ti (X) ₃ , Zr
(X) ₃ , Hg (X) or Sn (X) ₃ , where X is the same or different in each case;
_{^{1 (-M 1) a (-A}} 1 -M 2) b (-A 2 -M 3) c, halogen, 1 to 12 carbon atoms, preferably an alkyl or alkoxy group or a cycloalkyl having 1 to 6 carbon atoms A pentadienyl group, and when Met = B (X) ₂ , X may be OH].

The reaction conditions for this reaction and the preparation of the compounds of the formula (II) are described in detail in DE-A 39 60 663, which is hereby incorporated by reference.

Preferred compounds of formula (II) are those wherein Met is B
X ¹ X ² . Wherein X ¹ and X ² are the same or different and are —OH, C ₁ -C ₄ -alkoxy or halogen, or X ¹ and X ² are
₁ -C ₄ - or to form a alkylenedioxy group, or X
¹ and X ² and the boron atom together form a boroxine ring:

Embedded image Part of.

The reaction can be carried out, for example, by homogeneous catalysis with a Pd (0) complex such as tetrakis (triphenylphosphine) palladium (0). Such a process is described, for example, in Synth. Comm. 19
81, 11, 513; EP-A 0 354 434 and E
P-A0470795.

It is also possible to use metal palladium as a catalyst, preferably in the presence of a phosphine ligand. This type of process is described, for example, in WO-A94 /
10105.

For example, EP-A0679619 or E
Palladium catalyzed coupling processes in the presence of a water-soluble phosphorus-containing ligand, preferably phosphine, as described in P-A 0 694 530 are preferred.

To carry out the process, a catalytic amount of a palladium compound soluble in an aromatic boron compound, a thiadiazole derivative, a base, an organic solvent and a water-soluble ligand is combined with water and one or more inert organic compounds. Introduced into a mixture of solvents, from 0 ° C. to 200 ° C., preferably 30 ° C.
At a temperature of from 50 ° to 170 ° C., particularly preferably from 50 ° to 150 ° C., very preferably from 60 ° to 120 ° C., for 1 hour to 100 hours, preferably 5 hours to 7 hours.
Stir for 0 hours, particularly preferably for 5 to 50 hours.

Next, a post-treatment is carried out by a method known per se and commonly used by those skilled in the art.

To avoid contamination of the product by palladium, for example, a sufficient amount of complex ligand can be added to the reaction mixture after the reaction is completed, so that all palladium is incorporated into the aqueous phase. However, if desired, it is also possible to add, when the reaction is completed, a water-soluble complexing agent which is not the same as that used for the reaction, in order to transfer all the palladium to the aqueous phase.

If desired, the palladium can also be removed by chromatographic methods or by precipitation, for example, as a sulfide.

For further work-up after phase separation, the crude product is usually separated from the solvent and then processed in a manner suitable for the particular product, such as recrystallization, distillation, sublimation, zone melting, melting Further purification by crystallization or chromatography.

Organic solvents suitable for the process and forming an organic phase in the reaction medium include, for example, ethers such as diethyl ether, dimethoxymethane, diethylene glycol dimethyl ether, diisopropyl ether, tert-butyl methyl ether, hexane, Hydrocarbons such as isohexane, heptane, cyclohexane, benzene, toluene, xylene, etc., ketones such as 1-butanol, 2-butanol, tert-butanol, higher alcohols which are infinitely miscible with water, and isobutyl methyl ketone such as amyl alcohol , Dimethylacetamide,
Amides such as N-methylpyrrolidone; nitriles such as butyronitrile; and mixtures thereof.

In a particularly preferred variant, the novel process uses water, one or more water-insoluble solvents and one or more water-soluble solvents.

Preferred organic co-solvents that are miscible with the aqueous phase include nitriles such as acetonitrile, formamides such as DMF, lower alcohols such as methanol, ethylene glycol and ethanol, sulfoxides such as DMSO, and THF or dioxane. Cyclic ethers.

Preferred reaction media comprising water, a water-soluble organic solvent and a water-insoluble organic solvent are water, a mixture of toluene and ethanol, water, a mixture of toluene and tetrahydrofuran, and a mixture of water, toluene and acetonitrile, respectively. In some cases, a 1: 2: 1 capacity ratio is preferred.

Bases commonly used in the process include hydroxides of alkali metals and alkaline earth metals,
Alkali metal and alkaline earth metal carbonates, alkali metal bicarbonates, alkali metal and alkaline earth metal acetates, alkali metal and alkaline earth metal alkoxides, and primary, secondary and tertiary amines. .

The base is usually from 100 to 1000 mol%, particularly preferably from 100 to 500 mol%, very particularly preferably 1 to 100 mol%, based on the aromatic boron compound.
50 to 400 mol%, especially 180 to 250 mol
% Used.

The catalyst used is a palladium compound soluble in an organic solvent, for example, palladium ketonate, palladium acetylacetonate, nitrile palladium halide, olefin palladium halide, palladium halide, allylpalladium halide and palladium biscarboxylate a rate, preferably a palladium diketonate, palladium acetylacetonate, bis eta ² - olefin palladium dihalide, palladium (II) halides, eta ³ - allyl palladium halides dimers and palladium biscarboxylates, very particularly More preferably, bis (dibenzylideneacetone) palladium (0) [Pd (db
a) ₂ )], Pd (dba) ₂ · CHCl ₃ , palladium bisacetylacetonate, bis (benzonitrile) palladium dichloride, PdCl ₂ , Na ₂ PdCl ₄ , dichlorobis (dimethylsulfoxide) palladium (II), dichloride Bis (acetonitrile) palladium, palladium-
II acetate, palladium-II propionate, palladium-II butoxide and (1c, 5c-cyclooctadiene) palladium dichloride.

The palladium catalyst is generally from 0.001 to 10 mol%, preferably from 0.01 to 5 mol%, particularly preferably from 0.05 to 3 mol%, very preferably from 0.05 to 3 mol%, based on the aromatic halide or perfluoroalkylsulfonate. Preferably 0.1 to 1.5 mol
% Used.

Suitable water-soluble ligands are, for example, sulfates and / or sulfate radicals and / or carboxylate and / or carboxylic acid radicals and / or phosphonate and / or phosphonate radicals and / or
Or a phosphonium group and / or a peralkylammonium group and / or a hydroxyl group and / or a polyether group having an appropriate chain length.

Preferred types of water-soluble ligands include phosphines substituted with the above groups, for example, trialkylphosphines, tricycloalkylphosphines, triarylphosphines, dialkylarylphosphines, alkyldiarylphosphines, and tripyridylphosphines and tripyridylphosphines. A heteroarylphosphine such as furylphosphine, wherein the three substituents on phosphorus may be the same or different, may be chiral or achiral, and one or more of the ligands may be A plurality of phosphorus groups of phosphine may be linked,
Part of this linkage may be one or more metal atoms, and may be phosphites, phosphinates, and phosphonite, phosphole, dibenzophosphole, and cyclic or oligocyclic or polycyclic compounds containing phosphorus atoms. There may be.

The water-soluble ligands are generally from 0.001 to 20 mol%, preferably from 0.01 to 15 mol%, particularly preferably from 0.05 to 10 mol%, based on the aromatic halide or perfluoroalkylsulfonate, very preferably from 0.05 to 10 mol%. Preferably 0.1 to 6 mol
% Used.

If desired, it is also possible to use a mixture of two or more different water-soluble complex ligands. Most of the water-soluble complex ligands are known from the literature. The synthesis of these compounds is described, for example, in W.S. A. Her
rmann and C.I. W. Kohlpaper, A
ngew. Chem. Int. Ed. Engl. 32
(1993) 1524 and the references cited therein, or can be carried out by methods known from, or analogous to, those familiar to those skilled in the art. For example, the manufacture of BINAS is described, for example, in German Patent Application P 4244274.

The coupling products are likewise of the formula (III)
R ¹ (-M ¹ ) _a (-A ¹ -M ² ) _b -A ² -YX (III) wherein X is Br or I; , 5-thiadiazole-3,4-diyl; other symbols and indices are as defined in formula (I)].

Preferred compounds of formula (III) result from preferred compounds of formula (I).

The novel compounds of the formula (III) can be used for a wide variety of 1,2,5-
It allows thiadiazole derivatives to be synthesized in a significantly reduced number of synthesis steps. In addition, the use of explosive or very toxic compounds is not required.

These intermediate compounds of the formula (III) can be converted into the novel compounds of the formula (I), for example by further boric acid coupling.

Compounds in which M ³ and / or M ⁴ are —O—CH ₂ — can be prepared by converting an alkoxide or phenoxide to a compound of the formula (III) or 3,4-dihalo-1,2,5-
It can be produced by reacting with thiadiazole.

To prepare compounds wherein M ³ and / or M ⁴ are --CO--O--, the corresponding halogen compound of formula (III) or 3,4-dihalo-1,2,5-thiadiazole organometallic compounds, for example into a Grignard compound can then be reacted with CO _2. Subsequent reduction allows M ³ or M ^{4 to} be —CH ₂ —O
Is obtained.

Similar thio compounds can be prepared using thioxides, thiophenoxides and carbon disulfide.

When M ³ or M ⁴ is —CH ＝ CH— or —C
Compounds that are ≡C-groups undergo Heck reactions (eg, Heck, Palladium Reagent).
sin Organic Synthesis, pp.
179-321, Academic Press, Ne
w York, 1985) or DE-
It can be obtained as described in A4438586.

R ¹ (−M ¹ ) _a (−A ¹ −M ² ) _b (−A ² −
M ³ ) _c or (−M ⁴ −A ³ ) _d (−M ⁵ −A ⁴ ) _e (−
Synthesis of M ⁶⁾ _f -R ² radicals are known per se carried out by customary methods familiar to those skilled in the art.

This preparation is carried out under reaction conditions known and suitable for the reaction. Modifications known per se can be used for this purpose, but are not described in detail here.

For example, a compound containing a 1,4-cyclohexylene group and a 1,4-phenylene group is described in DE-A.
A2344732, 2450088, 2429093,
2502904, 2636684, 2701591 and 2752975; DE-A26441724 for compounds containing a pyrimidine-2,5-diyl group; DE-A4 for compounds containing a pyridine-2,5-diyl group.
022223 and EP-A 0 391 203; DE-A for compounds containing a pyridazine-3,6-diyl group
3231462; 1,3,4-thiadiazole-2,5
EP-A 3095 for compounds containing -diyl groups
14; for the naphthalene-2,6-diyl group, WO-
A92 / 16500; For the bicyclo [2.2.2] octane-1,4-diyl group, DE-A371089
0; for the dioxaborinane-2,5-diyl group,
K. Seto et al. , J. et al. Chem. Soc.
Chem. Comm. (1988), 56, respectively.

The preparation of disubstituted pyridines, disubstituted pyrazines, disubstituted pyrimidines and disubstituted pyridazines
For example, the series "The Chemistry of
Heterocyclic Compounds ",
A. Weissbergerland E.C. C. Tayl
or (editors) in the corresponding volume.

The dioxane derivative can be appropriately produced by reacting a suitable aldehyde (or a reactive derivative thereof) with a suitable 1,3-diol (or a reactive derivative thereof). The reaction is preferably carried out in the presence of an inert solvent such as benzene or toluene and / or in the presence of a catalyst such as a strong acid (eg sulfuric acid, benzenesulfonic acid or p-toluenesulfonic acid) from about 20 ° C to about 15 ° C.
It is carried out at a temperature of 0 ° C., preferably between 80 ° C. and 120 ° C. A suitable reactive derivative of the starting material is a primary acetal.

Some of the aldehydes and 1,3-diols and their derivatives are known, and some can be easily prepared from compounds known from the literature by standard methods of organic chemistry. For example,
Aldehydes can be obtained by oxidation of the corresponding alcohols or reduction of nitriles or the corresponding carboxylic acids or derivatives thereof, and diols can be obtained by reduction of the corresponding diesters.

Compounds in which the aromatic ring is substituted by at least one fluorine atom can also be obtained from the corresponding diazonium salts, for example from Balz and Seaman
According to the method of Schimann), the diazonium group can be substituted with a fluorine atom.

For the bonding of the ring systems to one another, see for example: EP-A 694 530, EP-A 6796 for the direct bonding between aromatic and heteroaromatic rings.
19, N.M. Miyaura, T .; Yanai, an
d A. Suzuki, Synth. Comm. 198
1,11,513, J. K. Still, Ang
w. Chem. , Int. Ed. Eng. 1986, 2
5,508, DE-C3930663; J. Sha
rp, W.C. Cheng, V .; Sneekus, Tet
rahedron Letters 1987, 28,
5093, G.C. W. Gray, J.M. Chem. Soc.
Perkin Trans. II, 1989, 2041
And Mol. Cryst. Liq. Cryst. 19
89, 172, 165, 1991, 204, 43 and 91, EP-A 0 449 015, WO-A 89/120.
39, WO-A89 / 03821, EP-A03544
34; for compounds containing a —CH ₂ CH ₂ — bridge,
EA3201721; For compounds containing a -C≡C-bridge, see Koji Seto et al. , Liq
uid Crystals 1990, 8, 861.

The esters of the formula (I) can be obtained by esterifying the corresponding carboxylic acids (or their reactive derivatives) with alcohols or phenols (or their reactive derivatives), or by the DCC method (DCC = Dicyclohexylcarbodiimide).

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

Particularly suitable reactive derivatives of said carboxylic acids are the acid halides, especially the chlorides and bromides, and also the anhydrides, for example mixed anhydrides, azides or esters, especially those having 1-4 carbon atoms in the alkyl radical. Alkyl ester.

Particularly suitable reactive derivatives of said alcohols or phenols are the corresponding metal alkoxides or phenoxides, preferably alkoxides or phenoxides of alkali metals such as sodium or potassium.

The esterification is advantageously carried out in the presence of an inert solvent. Particularly suitable solvents are ethers, such as diethyl ether, di-n-butyl ether, THF, dioxane or anisole; ketones, such as acetone, butanone or cyclohexanone; amides, such as DMF or hexamethylphosphoric triamide; hydrocarbons, such as benzene, toluene Or xylene; halogenated hydrocarbons such as tetrachloromethane, dichloromethane or tetrachloroethylene; and sulfoxides such as dimethylsulfoxide or sulfolane.

The ethers of the formula (I) are obtained by etherification of the corresponding hydroxyl compound, preferably of the corresponding phenol. First, the hydroxyl compound is
By treatment with H, NaNH ₂ , NaOH, KOH, Na ₂ CO ₃ or K ₂ CO ₃ , they are appropriately converted to the corresponding metal derivatives, for example the corresponding alkali metal alkoxides or alkali metal phenoxides. Next,
Reaction with a suitable alkyl halide, alkyl sulfonate or dialkyl sulfate in an inert solvent such as acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide, or with excess aqueous or aqueous / alcoholic NaOH or KOH , About 2
The reaction can be performed at 0-100 ° C.

With respect to the synthesis of specific groups R ¹ , for example, EP-A 0 355 008 for silicon-containing side chains
And EP-A 029954 and EP-A 03981 for compounds containing a cyclopropyl group in the side chain.
55 can be further referenced.

Providing a compound of formula (I) generally broadens the range of liquid crystal materials suitable for preparing liquid crystal mixtures from various application points of view.

In this respect, the compounds of the formula (I) have a wide range of applications. Depending on the choice of the substituent, the formula (I)
The compound of formula (I) can be used as a liquid crystal basic material mainly composed of a liquid crystal phase. However, the compound of formula (I) can be added to a liquid crystal basic material composed of another type of compound, for example, to obtain a dielectric material of this type. The anisotropy and / or optical anisotropy can be changed to optimize the voltage threshold and / or viscosity.

The invention also relates to the use of the compounds of the formula (I) in liquid-crystal mixtures, preferably in ferroelectric and nematic, in particular in ferroelectric mixtures.

The invention further relates to liquid-crystal mixtures, preferably ferroelectric and nematic, in particular ferroelectric mixtures, containing one or more compounds of the formula (I).

The novel liquid crystal mixture generally has 2 to 35 components,
It preferably contains 2 to 25 components, particularly preferably 2 to 20 components.

These mixtures are generally prepared as 0.01-8
0% by weight, preferably 0.1-60% by weight, particularly preferably 0.1-30% by weight, of one or more, preferably 1-10, particularly preferably 1-5, very preferred Include 1-3 novel compounds of formula (I).

The other components of the liquid-crystal mixtures containing the novel compounds of the formula (I) are preferably smectic and / or
Or selected from known compounds having a nematic and / or cholesteric phase. These compounds include, for example:-for example WO86 / 06401 and US-A48
74542, phenylpyrimidine derivatives, for example, meta-substituted 6-membered aromatic compounds described in EP-A0578054, for example, silicon compounds described in EP-A0355008,-for example, described in EP-A0541081 , 1
Mesogenic compounds having only two side chains, for example hydroquinone derivatives as described in EP-A 0603786, for example pyridylpyrimidines as described in WO 92/12974, Keller, Ferroselect
rics 58 (1984), 3; W. Goo
dby, et al. , Liquid Crystal
s and Ordered Fluids, Vol.
4, phenylbenzoate as described in New York, 1984; and 1, for example, as described in EP-B309514.
3,4-thiadiazole.

Suitable chiral non-racemic dopants include, for example, the following: Keller, Ferroselect
rics 1984, 58, 3 and J.C. W. Good
by, et al. , Liquid Crystals
and Ordered Fluids, Vol.
4, optically active phenylbenzoates described in New York, 1984, for example, EP-A0263437 and WO-A9
Optically active oxirane ethers described in 3/13093, for example optically active oxirane esters described in EP-A 0 292 954, for example optically active dioxolane ethers described in EP-A 0 351 746, for example EP- Optically active dioxolane esters described in A03661272, and optically active tetrahydrofuran-2-carboxylic acid esters as described, for example, in EP-A0355561.

The mixtures can also be used in the field of electro-optical or completely optical elements, such as display elements, switching elements, light modulators, image processing and / or signal processing elements, or in general the field of non-linear optics. it can.

The liquid crystal mixture containing the compound of the formula (I)
Particularly suitable for use in electro-optical switching and display devices (displays). Usually, these displays are constructed in such a way that the liquid crystal layer is sandwiched on both sides by layers which are usually in the order of a liquid crystal layer, at least one alignment film, an electrode and a limiting plate (for example made of glass). In addition, these displays may also include spacers, adhesive frames, polarizers, and thin color filter layers for color display. In addition, an antireflection layer, a passivation layer, a compensation layer and a barrier layer,
And components such as thin film transistors (TFTs) and electrically nonlinear elements such as metal / insulator / metal (MIM) elements. The structure of a liquid crystal display has already been described in detail in the relevant monograph (for example, E.C.
Kaneko, "LiquidCrystal TV
Displays; Principles and A
applications of Liquid Cry
stall Displays ”, KTK Scient
if Publishers, 1987).

The novel FLC mixtures are also suitable for use in display devices operating in reverse mode or τV (min) mode. Furthermore, the mixture is also suitable for electric field treatment, ie when operating in a quasi-bookshelf structure (QBG). (For example, H. Ri
eger et al. , SID 91 Digest
(Anaheim), 1991, p. 396).

The new mixtures also have a DHF effect or PS
It is also suitable for use in ferroelectric liquid crystal displays based on the use of the FLCD effect (pitch stabilized ferroelectric liquid crystal display, also known as SBF (short pitch bistable ferroelectric) effect).

Furthermore, the compounds of the formula (I) can also be used as components of an antiferroelectric liquid crystal mixture.

The present invention will be described in more detail by the following examples, which do not limit the invention.

[0085]

【Example】

A: Compound of formula (I) (Example 1) 3- (6-decaneoxy-2-fluoropyrid-3-yl) -4-phenyl-1,2,5-thiadiazole (6-decaneoxy-2-fluoropyrido-3) -Ill)
Boric acid (3.7 g; 12.4 mmol) and 3-bromo-4-phenyl-1,2,5-thiadiazole (1.
0 g; 4.15 mmol) in sodium carbonate (3.9).
5 g), toluene (50 ml), ethanol (25 m
1) and water (25 ml) and a mixture of palladium (II) chloride as catalyst (1 mol%) and trisodium triphenylphosphine trisulfonate (5 mol%) under reflux for 6 hours. By aqueous workup and column chromatography _{(SiO 2 / CH 2 Cl 2} ), 1.
4 g (82% of theory) of 3- (6-decaneoxy-2)
-Fluoropyrid-3-yl-4-phenyl-1,2,2
5-Thiadiazole was obtained.

Example 2 3,4-bis (6-dodecaneoxy-2-fluoropyrid-3-yl) -1,2,2
5-thiadiazole (6-dodecaneoxy-2-fluoropyrid-3-yl) boric acid (2.8 g; 8.6 mmol) and 3,4
-Dibromo-1,2,5-thiadiazole (1.0 g;
4.1 mmol) with sodium carbonate (3.91 g), xylene (40 ml), ethanol (20 ml) and water (20 ml), and palladium chloride (I
Refluxed in a mixture of I) (1 mol%) and trisodium triphenylphosphine trisulfonate (5 mol%) for 15 hours. 1.12 g by aqueous work-up and column chromatography (SiO ₂ / CH ₂ Cl ₂ )
(42% of theory) of 3,4-bis (4-dodecaneoxy-2-fluoropyridyl) -1,2,5-thiadiazole was obtained.

Example 3 3- (4-Cyclohexylphenyl) pyrimidin-2-yl) -4-ethyl-1,
2,5-thiadiazole (4-ethyl-1,2,5-thiadiazol-3-yl) boric acid (1.0 g; 6.4 mmol) and 2-
(4-Cyclohexylphenyl) -5-bromopyrimidine (1.0 g; 3.2 mmol) was treated with sodium carbonate (2.9 g), toluene (30 ml), glycerol (15 ml) and water (15 ml), and tetrakis as a catalyst. The mixture was refluxed for 15 hours in a mixture of (triphenylphosphine) palladium (0) (1 mol%).
Aqueous work-up and column chromatography (SiO ₂
/ CH ₂ Cl ₂ ), 0.65 g (58% of theory)
3- (4-cyclohexylphenyl) pyrimidine-2
-Yl) -4-ethyl-1,2,5-thiadiazole was obtained.

Example 4 3-Octyl-4-phenyl-1,2,5-thiadiazole 3-bromo-4-phenyl-1,2,5-thiadiazole (2.9 g; 12 mmol) was added under a protective gas atmosphere. 1-octylmagnesium bromide (4.6 g; 24 mmol
l) in THF (80 ml), then add THF
1,3-bis (diphenylphosphinopropane) nickel (II) chloride (0.15 mmol) dissolved in
C. was added dropwise. The mixture was then stirred at this temperature for 4 hours, acidified with hydrochloric acid (pH〜2), the organic phase was separated off and evaporated. The crude product was recrystallized from acetonitrile.

Yield: 1.2 g (36% of theory) of 3-
Octyl-4-phenyl-1,2,5-thiadiazole.

B. Example 5 Synthesis of Compound of Formula (III) 3-Bromo-4-phenyl-1,2,5
-Thiadiazole phenylboric acid (2.0 g; 16.4 mmol) and 3,4-dibromo-1,2,5-thiadiazole (4.
0 g; 16.4 mmol) and sodium carbonate (15.
64 g), toluene (60 ml), ethylene glycol (30 ml) and water (30 ml), and palladium (II) chloride (1 mol%) as a catalyst and triphenylphosphine trisulfonate trisodium (5 mol)
1%) in the mixture for 24 hours. Aqueous work-up and column chromatography _{(SiO 2 / CH 2 Cl 2} /
Ethyl acetate 9: 1) gives 1.5 g (38. theoretical amount).
%) Of 3-bromo-4-phenyl-1,2,5-thiadiazole.

Example 6 3-Bromo-4- (4-octyloxyphenyl) -1,2,5-thiadiazole 4-octyloxyphenylboric acid (5.9 g;
6 mmol) and 3,4-dibromo-1,2,5-thiadiazole (5.8 g; 23.6 mmol) were treated with sodium carbonate (19.56 g), toluene (70 ml),
1 in a mixture of acetonitrile (35 ml) and water (35 ml) and tetrakis (triphenylphosphine) palladium (0) (10 mol%) as catalyst.
Refluxed for 4 hours. By aqueous workup and column chromatography _{(SiO 2 / CH 2 Cl 2} ), 5.6g (65% of theory) of 3-bromo-4- (4-octyloxy-phenyl) -1,2,5-thiadiazole I got

Example 7 3-bromo-4- (4-pentylcyclohexylmethoxy) -1,2,5-thiadiazole 4-pentylcyclohexylcarbinol (1.5 g;
8.15 mmol) in dimethylformamide (40 m
l) and sodium hydride (0.3 g; 12.2)
3 mmol) was added over about 15 minutes at room temperature. After gas evolution was complete, 3,4-dibromo-1,2,5-thiadiazole (2.95 g; 12.23 mmol) was added to the resulting alkoxide and the mixture was stirred at 50 ° C. for 6 hours, ice / It was poured into a water mixture, filtered by suction and extracted. Column chromatography (SiO ₂ / CH ₂ C
1.2 g (43% of theory) by separation according to l ₂ )
Of 3-bromo-4- (4-pentylcyclohexylmethoxy) -1,2,5-thiadiazole.

Example 8 (4-phenyl-1,2,2,
3-Thiadiazol-3-yl) boric acid 3-bromo-4-phenyl-1,2,5-thiadiazole (1.7 g; 7.06 mmol) is dissolved in 10 ml of anhydrous tetrahydrofuran, and -78 ° C under a protective gas atmosphere.
And cooled. 4.7 ml (7.5 mmol) of a 1.6 molar n-butyllithium solution in n-hexane was added dropwise over 30 minutes. The mixture was stirred at -78 ° C for another 30 minutes. Next, 1.0 mole ZnC in diethyl ether
l was slowly dropwise ₂ solution 21.6 ml (21.6 mmol). During this time the temperature must not exceed -60 ° C. When the addition was complete, the mixture was stirred for another 30 minutes.

The corresponding boric acid is 3-bromo-4-alkyl-1,2,5-thiadiazole or 3-bromo-
It can be similarly prepared from 4-alkyloxy-1,2,5-thiadiazole. (4-substitution 1,
The crude 2,5-thiadiazol-2-yl) boric acid was used directly in the coupling reaction without isolation, as described in Part A of the Examples.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication // C07M 7:00 (72) Inventor Barbara Hornung, Germany 63594 Haselrod, Schulstrasse 21a

Claims (10)

[Claims] (1) Formula (I): R ¹ (−M ¹ ) _a (−A ¹ −M ² ) _b (−A ² −M ³ ) _c −Y (−M ⁴ −A ³ ) _d (−M _{^{5 - a 4) e (-M}} 6) f R 2 (I) [ wherein the symbols and indices have the following meanings: Y is embedded image And R ¹ and R ² are the same or different and are hydrogen or a linear or branched alkyl group having 1 to 20 carbon atoms (whether having or not having an asymmetric carbon atom). is good), the one or more CH ₂ groups where, -O -, - S -, - CO -, - CS -, - CH = C
H-, -C≡C-, -CO-O-, -O-CO-, -O
-CO-O-, cyclopropane-1,2-diyl, -S
_{i (CH 3) 2 -,} 1,4- phenylene, trans-1,
It may be substituted by 4-cyclohexylene or trans-1,3-cyclopentylene, provided that the oxygen and / or sulfur atoms are not directly linked to each other and / or one or more of the alkyl groups -F hydrogen atoms, -Cl, may be substituted with -Br or -OR ^3, or R ^1, is in one of the following groups (or is racemic optically active) Available: Embedded image R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are the same or different,
Hydrogen or a linear or branched alkyl group having 1 to 16 carbon atoms, which may or may not have an asymmetric carbon atom, wherein one or more CH _{The two} groups may be substituted with -O- and / or -CH = CH-, provided that the oxygen atoms are not directly bonded to each other and / or one or more hydrogen atoms of the alkyl group are Or R ⁴ and R ⁵ may be taken together when attached to an oxirane, dioxolane, tetrahydrofuran, tetrahydropyran, butyrolactone or valerolactone system. -(CH ₂ ) _4- or-(C
H ₂ ) _5- ; M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶ may be the same or different and are —O—, —S—, —C
O-, -CO-O-, -O-CO-, -O-CO-O
-, -CO-S-, -S-CO-, -CS-O-, -O
-CS-, -S-CS-S-, -O-CS-O-, S-
CO-S -, - CS - , - CH 2 -O -, - O-CH
_{2 -, - CH 2 -S -} , - S-CH 2 -, - CH = CH
-, -C≡C- or a single bond; A ¹ , A ² , A ³ and A ⁴ are the same or different and one or more hydrogen atoms are replaced by F, Cl and / or CN 1,4-phenylene, pyrazine-2,5-diyl in which one or two hydrogen atoms may be substituted with F, Cl and / or CN, one or two hydrogen atoms in F , 2-pyridazine-3,6-diyl optionally substituted with Cl and / or CN, pyridine-2,5-optionally substituted one or more hydrogen atoms with F, Cl and / or CN Diyl, pyrimidine-2,5-diyl, in which one or two hydrogen atoms may be replaced by F, Cl and / or CN, one or two hydrogen atoms replaced by CN and / or CH ₃ Transformers that may be 1,4-cyclohexylene, 1,
3,4-thiadiazole-2,5-diyl, 1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5
-Diyl, wherein one hydrogen atom is F, Cl and / or C
1,3-thiazole-2,4 which may be substituted by N
-Diyl, wherein one hydrogen atom is F, Cl and / or C
1,3-thiazole-2,5 which may be substituted by N
-Diyl, wherein one hydrogen atom is F, Cl and / or C
Thiophene-2,4-diyl optionally substituted with N, thiophen-2,5-diyl optionally substituted with one or two hydrogen atoms by F, Cl and / or CN, piperazine-1 , 4-diyl, piperazine-2,
5-diyl, one or more hydrogen atoms is F, Cl
And / or naphthalene-2,6-diyl optionally substituted with CN, bicyclo [2.2.2] wherein one or more hydrogen atoms may be substituted with F, Cl and / or CN Octane-1,4-diyl, 1,
3-dioxaborinane-2,5-diyl, or a group Y; a, b, c, d, e and f are 0 or 1, and the sum of b, c, d and e is 1, 2 or 3 Can be]. 1,2,5-thiadiazole derivative. 2. In the formula (I), the symbols and subscripts have the following meanings: R ¹ and R ² are the same or different and are hydrogen or a linear or branched alkyl group having 1-18 carbon atoms. (Which may or may not have an asymmetric carbon), wherein one or more CH ₂ groups are —O—, —CO—, —O—CO—, —CO— O-,
-CH = CH-, -C≡C-, cyclopropane-1,2
- diyl, -Si (CH _{3) 2} - or trans-1,4
-Cyclohexylene, provided that the oxygen atoms are not directly bonded to each other and / or one or more hydrogen atoms of the alkyl group are -F, -Cl
Or -OR ³ , or R
¹ is any of the following groups (optically active or racemic): R ³ , R ⁴ and R ⁵ are the same or different and are hydrogen or a linear or branched alkyl group having 1 to 12 carbon atoms (whether having or not having an asymmetric carbon atom); is good), wherein one or more CH ₂ groups, -O- and / or -CH = CH- may be substituted with, except oxygen atoms not directly bonded to each other,
And / or one or more hydrogen atoms of the alkyl group may be replaced by -F or -Cl; or R ⁴ and R ⁵ together when bonded to a dioxolane system — (CH ₂ ) ₄ — or — (CH ₂ ) ₅
M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶
Are the same or different, and are -O-, -CO-, -CO-O
-, - O-CO -, - O-CO-O -, - CH 2 -O
—, —O—CH ₂ —, —CH ＝ CH— or a single bond; A ¹ , A ² , A ³ and A ⁴ are the same or different;
1,4-phenylene in which one or more hydrogen atoms may be replaced by F, Cl and / or CN, wherein one or more hydrogen atoms is F, Cl and / or C
Pyridine-2,5-diyl optionally substituted with N,
One or two hydrogen atoms are F, Cl and / or C
Pyrimidine-2,5-diyl optionally substituted by N, wherein one or two hydrogen atoms are CN and / or C
Trans-1,4-cyclohexylene optionally substituted with H ₃ , 1,3-dioxane-2,5-diyl, 1
Naphthalene-2,6-diyl optionally substituted by one or more hydrogen atoms with F, Cl and / or CN, or a group Y; a, b, c, d, e and f
Is 0 or 1, and the sum of b, c, d and e can be 1, 2 or 3. The 1,2,5-thiadiazole derivative of formula (I) according to claim 1, wherein 3. In the formula (I), the symbols and subscripts have the following meanings: R ¹ and R ² are the same or different and are hydrogen or a linear or branched alkyl group having 1 to 12 carbon atoms. (Which may or may not have an asymmetric carbon), wherein one, two or three CH ₂ groups are -O-, -CO-O-, -O-CO -Or trans-1,4-cyclohexylene, provided that the oxygen atoms are not directly linked to each other and / or one or more hydrogen atoms of the alkyl group are
Or R ¹ is any of the following groups (optically active or racemic): R ³ is in each case the same or different and is hydrogen or a straight-chain alkyl group having 1 to 9 carbon atoms, wherein one or more CH ₂ groups are substituted by —O—. But oxygen atoms are not directly bonded to each other; M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶ may be the same or different and represent —O—, —CO—O—, —O -CO-,-
CH ₂ —O—, —O—CH ₂ — or a single bond;
A ¹ , A ² , A ³ and A ⁴ are the same or different,
1,4-phenylene in which two or three hydrogen atoms may be substituted by F, pyridine-2,5-diyl, pyrimidine- in which one or two hydrogen atoms may be substituted by F 2,5-diyl, trans-1,4-cyclohexylene in which one or two hydrogen atoms may be replaced by CN and / or CH ₃ , or one or two hydrogen atoms by F A, b, c, d and e are optionally substituted naphthalene-2,6-diyl;
The 1,2,5-thiadiazole derivative of formula (I) according to claim 1 or 2, wherein 0 or 1 and the sum of b, c, d and e can be 1 or 2. 4. Use of the 1,2,5-thiadiazole derivative of the formula (I) according to claim 1 as a component of a liquid crystal mixture. 5. One or more types of claim 1-3.
1,2,5- of the formula (I) described in one or more of
A liquid crystal mixture containing a thiadiazole derivative. 6. The liquid crystal mixture according to claim 5, which is ferroelectric. 7. 0.01 to 80% by weight of one to one
The liquid crystal mixture according to claim 5 or 6, comprising zero compounds of the formula (I). 8. A liquid crystal mixture comprising a support plate, an electrode, at least one polarizer, at least one alignment film, and a liquid crystal medium, wherein the liquid crystal medium is the liquid crystal mixture according to claim 5. Switching, and / or
Or display device. 9. A compound of the formula (III): R ¹ (-M ¹ ) _a (-A ¹ -M ² ) _b -A ² -YX (III) wherein the symbols and subscripts have the following meanings: : X is Br
Or I; Y is 1,2,5-thiadiazole-
R ¹ is the same or different in each case and is hydrogen or a straight-chain or branched alkyl group having 1 to 20 carbon atoms, even if it has an asymmetric carbon atom. a has may not be), one or more CH ₂ groups where is, -O -, - S -, -
CO-, -CS-, -CH = CH-, -C≡C-, -C
O-O -, - O- CO -, - O-CO-O-, _{cyclopropane-1,2-diyl, -Si (CH 3) 2 -} , 1,4
It may be substituted by phenylene, trans-1,4-cyclohexylene or trans-1,3-cyclopentylene, provided that the oxygen and / or sulfur atoms are not directly bonded to each other and / or One or more hydrogen atoms of the group is -F, -Cl, -B
r or -OR ³ , or R ¹
Is any of the following groups (optically active or racemic): Embedded image R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are the same or different,
Hydrogen or a linear or branched alkyl group having 1 to 16 carbon atoms, which may or may not have an asymmetric carbon atom, wherein one or more CH _{The two} groups may be substituted with -O- and / or -CH = CH-, provided that the oxygen atoms are not directly bonded to each other and / or one or more hydrogen atoms of the alkyl group are Or R ⁴ and R ⁵ may be taken together when attached to an oxirane, dioxolane, tetrahydrofuran, tetrahydropyran, butyrolactone or valerolactone system. -(CH ₂ ) _4- or-(C
H ₂ ) _5- ; M ¹ and M ² may be the same or different and are -O-, -S-, -CO-, -CO-O-,-
O-CO-, -O-CO-O-, -CO-S-, -S-
CO-, -CS-O-, -O-CS-, -S-CS-S
-, -O-CS-O-, S-CO-S-, -CS-,-
_{CH 2 -O -, - O-} CH 2 -, - CH 2 -S -, - S-
A ¹ and A ² are the same or different, and one or more hydrogen atoms are replaced by F, Cl and / or CN; CH ₂ —, —CH ＝ CH—, —C≡C— or a single bond; 1,4-phenylene, one or two
Pyrazine-2,5-diyl, one or two of which hydrogen atoms may be replaced by F, Cl and / or CN
Pyridazine-3,6-diyl, in which one hydrogen atom may be replaced by F, Cl and / or CN, one or more hydrogen atoms may be replaced by F, Cl and / or CN Pyridin-2,5-diyl, wherein one or two hydrogen atoms are optionally substituted with F, Cl and / or CN, one or two hydrogen atoms are CN and Trans-1,4-cyclohexylene optionally substituted with CH ₃ , 1,3,4-thiadiazole-2,5-diyl,
1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5-diyl, 1,3-thiazole- wherein one hydrogen atom may be substituted by F, Cl and / or CN 2,4-diyl, 1,3-thiazol-2,5-diyl in which one hydrogen atom may be substituted by F, Cl and / or CN, one hydrogen atom in F, Cl and / or Thiophene-2 optionally substituted with CN,
4-diyl, thiophene in which one or two hydrogen atoms may be replaced by F, Cl and / or CN
2,5-diyl, piperazine-1,4-diyl, piperazine-2,5-diyl, naphthalene-2,6 in which one or more hydrogen atoms may be substituted by F, Cl and / or CN -Diyl, bicyclo [2.2.2] octane-1,4-diyl, in which one or more hydrogen atoms may be replaced by F, Cl and / or CN, 1,3-dioxaborinane-2, 5-diyl, or a group Y; a and b are 0 or 1]
-Halo-1,2,5-thiadiazole derivatives. 10. Use of a 3-halo-1,2,5-thiadiazole derivative of the formula (III) according to claim 9 as an intermediate in the preparation of a component of a liquid crystal mixture.