DE19941651A1 - New fluorothiophene, furan, isoxazole, thiazole, cyclopentane, cyclopentene and alkylfluorothiophenecarboxylic acid compounds are useful in liquid crystals mixtures and synthesis of liquid crystals, agrochemicals and pharmaceuticals - Google Patents

Abstract

New compounds with a 5-membered ring are 4- and 5-fluorothiophen-2,5-diyl, 3- and 5-fluorothiophen-2,4-diyl, furan-2,5- and -2,5-diyl, isoxazol-3,5-diyl, thiazol-2,5- and -2,4-diyl, cyclopentan-1,3-diyl and cyclopenten-1,3-diyl carboxylic ester, alcohol, ether and alkane compounds (I). New compounds with a 5-membered ring are 4- and 5-fluorothiophen-2,5-diyl, 3- and 5-fluorothiophen-2,4-diyl, cyclopentan-1,3-diyl and cyclopenten-1,3-diyl carboxylic ester, alcohol, ether and alkane compounds (I) of the following formula. R<1> - X - (A<1> - M<1>)a-(A<2> -M<2>)b - A<3> - Y - E (I) E = T-Z-R<2> group containing a 5-membered ring; T = 4- or 3-fluorothiophenyl-2,5-diyl, 3- or 5-fluorothiophenyl-2,4-diyl, furan-2,5- or -2,4-diyl, isoxazol-3,5-diyl, thiazol-2,5- or -2,4-diyl cyclopentan-1,3-diyl or cyclopenten-1,3-diyl; Z = a single bond or ether oxygen (-O-); R<1>, R<2> = hydrogen (H) or linear or branched 1-20 carbon (C) (fluoro)alkyl (optionally with asymmetric C atoms and/or substituents in the chain), X = a single bond, -O-, -OC(=O)-, -C(=O)O- or -OC(=O)O-; Y = -OC(=O)-, -OCH2- or -CH2CH2-; A<1>, A<2>, A<3> = (substituted) phenylen-1,4- or -1,3-diyl, cyclohexan-1,4-diyl, 1-cyclohexen-1,4-diyl, 1-alkyl-1-silacyclohexan-1,4-diyl, pyridin-2,5-diyl, pyrimidin-2,5-diyl, cyclopenten-2,5-diyl or thiophen-2,5-diyl; M<1>, M<2> = -OC(=O)-, -OCH2-, -CH2CH2-, -OC(=O)CH2CH2-, -OCH2CH2CH2-, -CC-, -CH2CH2CH2CH2- or a single bond; a,b = 0 or 1. Certain combinations of substituents and specified cyclohexyl cyclopentanoate compounds (II) are excluded. The full definitions are given in DEFINITIONS (Full Definitions) Field. Independent claims are also included for: (1) new 5-alkyl-4- and -3-fluoro-thiophen-2-carboxylic acid compounds (III); (2) liquid crystal mixtures containing compound(s) (I); (3) ferroelectric switches and displays containing a liquid crystal mixture of this type.

Description

In addition to nematic and cholesteric liquid crystals, more recently also optically active inclined smectic (ferroelectric) liquid crystals in commercial display devices used.

Clark and Lagerwall were able to show that the use of ferroelectric Liquid crystals (FLC) in very thin cells for optoelectric switching or Display elements leads, which compared to the conventional IN ("twisted nematic ") cells have switching times that are up to a factor of 1000 faster (see e.g. EP-A 0 032 362). Because of this and others cheaper Properties, e.g. B. the bistable switching option and almost angle-independent contrast, FLCs are basically for Areas of application such as computer displays are well suited.

For a more in-depth discussion of the technical requirements for FLCs, go to European patent application 97118671.3 and DE-A 197 48 432 referred.

For use in ferroelectric liquid crystal mixtures, especially in When operated in inverse mode, 3,5-diarylisoxazoles are described in JP-A 10-333113.

But since the development, especially of ferroelectric Liquid crystal mixtures, in no way considered complete the manufacturers of displays are on the most varied Components for mixtures are of interest, among other things, because only  the interaction of the liquid crystalline mixtures with the individual Components of the display device or the cells (e.g. the orientation layer) Allows conclusions to be drawn about the quality of the liquid-crystalline mixtures.

It has now been found that isoxazole derivatives of the formula (I) are present in very small amounts Mixing quantities the properties of liquid crystal mixtures, in particular chiral-smectic mixtures, favorably affect, e.g. B. in terms of dielectric anisotropy and / or the melting point, but also with regard to the switching behavior, the values of the tilt angle or its Temperature dependence.

The invention therefore relates to isoxazole derivatives of the formula (I)

R ¹ -X- (A ¹ -M ¹ ) _a - (A ² -M ² ) _b -A ³ -YTZR ² (I),

where the symbols and indices have the following meanings:
T is undirected
Isoxazole-3,5-diyl
R ^{1 is} hydrogen or a straight-chain or branched C _1-20 alkyl or C _2-20 alkenykest (with or without asymmetrical C atoms), where

• a) one or two non-terminal CH ₂ groups can be replaced independently of one another by -O- or -C (= O) - with the proviso that two adjacent CH ₂ groups cannot be replaced at the same time and / or
• b) a CH ₂ group can be replaced by -C∼C- and / or
• c) a CH ₂ group by -Si (CH ₃ ) ₂ -, cyclopropane-1,2-diyl, cyclobutane-1,3-diyl, cyclopentane-1,4-diyl, bicyclo [1.1.1] pentane-1 , 3-diyl or cyclohexane-1,4-diyl can be replaced and / or
• d) one or more H atoms can be replaced by F and / or CN can;
• e) in the case of a branched alkyl radical having asymmetric carbon atoms, the asymmetric carbon atoms have either -CH ₃ , -OCH ₃ , -CF ₃ , F, CN and / or Cl as substituents or
  are built into a 3- to 7-membered ring, in which one or two non-adjacent CH ₂ groups can be replaced by -O- and a non-adjacent CH ₂ group by -OC (= O) -;

R ²

Hydrogen or a straight-chain or branched alkyl radical (with or without asymmetrical carbon atoms) with 1 to 20 carbon atoms, a non-terminal CH ₂

Group can be replaced by -O- or -OC (= O) - or -C (= O) O- and / or one or more H atoms can be replaced by F with the provisos,

• 1. That the -CH ₂ group closest to the isoxazole cannot be replaced by -O when Z is -O-
• 2. R ² can only be hydrogen if Z is a single bond.

X: a single bond, -O-, OC (= O) -, -C (= O) O- or -OC (= O) O-
Y: -OC (= O) -, -OCH ₂

-, -CH ₂

CH ₂

-
Z: a single bond or -O-
A ¹

, A ²

, A ³

are independently phenylene-1,4-diyl, optionally mono- or disubstituted by CN or F, phenylene-1,3-diyl, optionally mono- or disubstituted by CN or F, cyclohexane-1,4-diyl, where one or two H atoms through CN and / or CH ₃

and / or F can be replaced, 1-cyclohexene-1,4-diyl, where one H atom can be replaced by F, 1-alkyl-1-silacyclohexane-1,4-diyl, pyridine-2,5-diyl , optionally monosubstituted by F, pyrimidine-2,5-diyl, optionally monosubstituted by F, thiophene-2,5-diyl;
M ¹

, M ²

are undirected independently of each other
-OC (= O) -, -OCH ₂

, -CH ₂

CH ₂

-, -OC (= O) CH ₂

CH ₂

-, -OCH ₂

CH ₂

CH ₂

-, -C∼C-, -CH ₂

CH ₂

CH ₂

CH ₂

- or a single bond;
a, b are independently 0 or 1.
"Terminal" means e.g. B. in R ¹

the CH ₂ linked to X or H

-Groups. "non-directional" means the possibility of mirror-inverted installation of Group.

The following compounds of the formulas (I-1) to (I-15) are preferred

in which mean:
R ^{3 is} hydrogen or a straight-chain or branched alkyl radical (with or without asymmetrical carbon atoms) with 1 to 16 carbon atoms, in which a non-terminal CH ₂ group can also be replaced by -O- or non-directed -OC (= O) - can and in which one or more H atoms can be replaced by F;
R ^{4 is} hydrogen or a straight-chain or branched alkyl or alkyloxy radical (with or without asymmetrical carbon atoms) with 1 to 16 carbon atoms.

The compounds of the formula (I), in particular (I-1) to (I-16), in which R ^{3 is} a straight-chain alkyl radical having 2 to 16 C atoms and R ^{4 is} a straight-chain alkyl or alkyloxy radical with 1 to 16 carbon atoms mean.

The compounds of the formula (I), in particular (I-1) to (I-16), in which R ^{3 is} a straight-chain alkyloxy radical having 2 to 12 C atoms and R ^{4 is} a straight-chain alkyl or alkyloxy radical with 1 are also particularly preferred mean up to 12 carbon atoms.

Among the compounds of the formula (I) which are to be used as optically active components (dopant) in liquid-crystal mixtures, preference is given to those in which the alkyl group contains the asymmetric carbon atoms in the form of at least one of the groupings

• a) -CH (CH ₃ ) C _m H _{2m + 1} , where m has values from 2 to 8
• b) -OC.H (CH ₃ ) C _m H _{2m + 1} , where m has values from 2 to 8
• c) -OC.H (CH ₃ ) CO ₂ C _m H _{2m + 1} , where m has values from 1 to 10
• d) -OC (= O) CH (CH ₃ ) OC _m H _{2m + 1} , where m has values from 1 to 10
• e) -OC (= O) CH (F) C _m H _{2m + 1} , where m has values from 1 to 10
• f) -OCH ₂ CH (F) C _m H _{2m + 1} , where m has values from 1 to 10
• g) -OCH ₂ CH (F) CH (F) C _m H _{2m + 1} , where m has values from 1 to 10
• h) oxirane-2,3-diyl
  where C. marks the asymmetric carbon atom.

The compounds according to the invention are prepared per se methods known from the literature, as used in standard works on organic matter Synthesis, e.g. B. Houben-Weyl, Methods of Organic Chemistry, Georg- Thieme-Verlag, Stuttgart.

However, it may prove necessary to vary / modify the literature methods for the requirements of mesogenic building blocks, since e.g. B. functional derivatives with long (<C ₆ ) alkyl chains often show less reactivity than z. B. the methyl or ethyl analogs.

As for linking functional derivatives of isoxazoles with others As far as liquid crystal-specific building blocks are concerned, reference is expressly made to DE-A 197 48 432 referenced in the list of methods familiar to the expert is specified.

The invention also relates to the use of compounds of the formula (I) in liquid crystal mixtures, preferably smectic and nematic, chiral-smectic liquid crystal mixtures are particularly preferred. In particular use in chiral-smectic liquid crystal mixtures is preferred, which are operated in ads with active matrix elements.

The use in mixtures for active matrix is very particularly preferred. LCDs in which the chiral-smketic liquid crystal layer is a monostable Monodomaine trains.  

The invention furthermore relates to liquid crystal mixtures, preferably smectic and nematic, particularly preferably ferroelectric (Chiral smectic) liquid crystal mixtures containing one or more Compounds of formula (I).

The liquid crystal mixtures according to the invention generally contain 2 to 35, preferably 2 to 25, particularly preferably 2 to 20 components.

They generally contain 0.01 to 80 wt .-%, preferably 0.1 to 60% by weight, particularly preferably 0.1 to 30% by weight, of one or more, preferably 1 to 10, particularly preferably 1 to 5, very particularly preferably 1 to 3, the compounds of formula (I) according to the invention.

Other components of liquid crystal mixtures, the invention Compounds of formula (I) are preferably selected from the known compounds with smectic and / or nematic and / or cholesteric phases. In this sense, suitable others Mix components are particularly in the international Patent application PCT / EP 96/03154 and DE-A 197 48 432 listed on the reference is hereby expressly made.

The mixtures according to the invention can in turn be used in electro-optical or completely optical elements, e.g. B. display elements, Switching elements, light modulators, elements for image processing and / or Signal processing or in general in the field of non-linear optics.

Another object of the invention is therefore a switching and / or Display device, preferably a smectic, containing one Liquid crystal mixture comprising one or more compounds of the formula (I) contains.  

Ferroelectric switching and / or are particularly preferred Display devices that contain active matrix elements (see e.g. DE-A 198 22 830).

Various documents are cited in the present application, for example to illustrate the technical environment of the invention. To all these documents are hereby expressly referred to; they apply through Quotation as part of the present application.

The invention is further illustrated by the following examples without it wanting to restrict it.

example 1

3-propyloxy-isoxazole-5-carboxylic acid- [4- (5-undecyl-pyrimidine-2- yl) phenyl] esters

4.9 g of 4 - (5-undecyl-pyrimidin-2-yl) phenol, 1.7 g of 3-propyloxy-isoxazole-5-carboxylic acid (manufactured according to Xue et al., Bioorg. Med. Chem. Letters 8 (1998 ) 3499 by reaction of the commercially available 3-hydroxy-isoxazole-5-carboxylic acid methyl ester with 1-bromopropane at 60 ° C in dimethylformamide / potassium carbonate and subsequent saponification with LiOH in tetrahydrofuran) and 2.1 g of dicyclohexylcarbodiimide in 50 ml of dichloromethane for 24 hours at room temperature touched. After filtration, distillation of the dichloromethane, chromatographic purification (silica gel; dichloromethane / heptane) and recrystallization from acetonitrile, the target compound is obtained as colorless crystals with the phase sequence × 91 S _A 109 N 126 I.

Analogously to Example 1, the compounds (I-1) to (I-12) can be prepared in which R ^{4 represents} an alkyloxy radical; using the method of Dulin et al., Proc. Soc. exp. Biol. Med., 1966, 121, 777 prepared 3-alkyl-isoxazole-5-carboxylic acids, the compounds (I-1) to (1- (I-12) are also available, in which R ^{4 is} an alkyl radical.

Example 2 (3-Propyloxy-isoxazol-5-yl) methyl [4- (5-undecyl-pyrimidin-2-yl) phenyl] ether

To a reacted mixture of equimolar amounts of diethylazodicarboxylate and triphenylphosphine in THF, equimolar amounts of 4 - (5-undecyl pyrimidin-2-yl) phenol and 3-propyloxy-isoxazol-5-yl-methanol (produced by LiAlH ₄ reduction of 3-propyloxy -Isoxazole-5-carboxylic acid methyl ester). After 24 h at room temperature it is brought to dryness in a vacuum. After chromatographic purification (silica gel, dichloromethane) and recrystallization, the target compound can be obtained.

Analogously, the compounds (I-13) to (I-15) can be obtained.

Claims (7)

1. isoxazole derivatives of the formula (I),
R ¹ -X- (A ¹ -M ¹ ) _a - (A ² -M ² ) _b - A ³ -YTZR ² (I)
where the symbols and indices have the following meanings:
T is undirected
Isoxazole-3,5-diyl
R ^{1 is} hydrogen or a straight-chain or branched C _1-20 alkyl or C _2-20 alkenyl radical (with or without asymmetric C atoms), where

• a) one or two non-terminal CH ₂ groups can be replaced independently of one another by -O- or -C (= O) - with the proviso that two adjacent CH ₂ groups cannot be replaced at the same time and / or
• b) a CH ₂ group can be replaced by -C∼C- and / or
• c) a CH ₂ group by -Si (CH ₃ ) ₂ -, cyclopropane-1,2-diyl, cyclobutane-1,3-diyl, cyclopentane-1,4-diyl, bicyclo [1.1.1] pentane-1 , 3-diyl or cyclohexane-1,4-diyl can be replaced and / or
• d) one or more H atoms can be replaced by F and / or CN;
• e) in the case of a branched alkyl radical having asymmetric carbon atoms, the asymmetric carbon atoms -CH ₃ , -OCH ₃ , -CF ₃ , F, CN and / or Cl have as substituents or
  are built into a 3- to 7-membered ring, in which one or two non-adjacent CH ₂ groups can be replaced by -O- and a non-adjacent CH ₂ group by -OC (= O) -;

R ^{2 is} hydrogen or a straight-chain or branched alkyl radical (with or without asymmetrical carbon atoms) with 1 to 20 carbon atoms, where a non-terminal CH ₂ group is defined by -O- or -OC (= O) - or -C ( = O) can be O-replaced and / or one or more H atoms can be replaced by F with the provisos,

• 1. That the -CH ₂ group closest to the isoxazole cannot be replaced by -O- when Z is -O-
• 2. R ² can only be hydrogen if Z is a single bond.

X: a single bond, -O-, OC (= O) -, -C (= O) O- or -OC (= O) O-
Y: -OC (= O) -, -OCH ₂ -, -CH ₂ CH ₂ -
Z: a single bond or -O-
A ¹ , A ² , A ³ are independently phenylene-1,4-diyl, optionally mono- or disubstituted by CN or F, phenylene-1,3-diyl, optionally mono- or disubstituted by CN or F, cyclohexane -1,4-diyl, where one or two H atoms can be replaced by CN and / or CH ₃ and / or F, 1-cyclohexene-1,4-diyl, where one H atom can be replaced by F, 1-alkyl-1-silacyclohexane-1,4-diyl, pyridine-2,5-diyl, optionally monosubstituted by F, pyrimidine-2,5-diyl, optionally monosubstituted by F, thiophene-2,5-diyl;
M ¹ , M ² are independently non-directional -OC (= O) -, -OCH ₂ -, -CH ₂ CH ₂ -, -OC (= O) CH ₂ CH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -C∼C-, -CH ₂ CH ₂ CH ₂ CH ₂ - or a single bond;
a, b are independently 0 or 1. 2. Liquid crystal mixture containing at least one compound of the formula (I) according to claim 1. 3. Liquid crystal mixture according to claim 2, characterized in that it is ferroelectric (chiral smectic). 4. Liquid crystal mixture according to claim 2, characterized in that it is nematic. 5. Liquid crystal mixture according to one of claims 2 to 4, characterized characterized in that they contain 0.01 to 80% by weight of one or more Contains compounds of formula (I). 6. Ferroelectric switching and / or display device containing one Ferroelectric liquid crystal mixture according to claim 5. 7. Ferroelectric switching and / or display device according to claim 6, characterized in that it contains active matrix elements and the Liquid crystal layer forms a monostable monodomain.