DE19941649A1 - 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

Furan derivatives of the formula (I), DOLLAR AR 1 -X- (A 1 M 1) a - (A 2 -M 2) b -A 3 -YTZR 2 DOLLAR A, where, for example, DOLLAR AT furan-2,5-diyl or furan Is -2,4-diyl, DOLLAR AR 1 and R 2 are hydrogen, DOLLAR AX is a single bond, -O-, OC (= O) -, -C (= O) O- or -OC (= O) O- is, DOLLAR AY is -OC (= O) -, -OCH 2 - or CH 2 CH 2 -, DOLLAR AZ is a single bond or -O-, DOLLAR AA 1, A 2, A 3 are independently phenylene-1,4 -diyl, DOLLAR AM 1, M 2 independently of one another undirected DOLLAR A -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, DOLLAR A a, b are independently 0 or 1, DOLLAR A are used in FLC mixtures.

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 TN ("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 nematic liquid crystal mixtures, esters are the Furanacrylic acid with terminal polar phenols described in JP-A 6306098.

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 furan derivatives of the formula (I) below are already present in low admixing quantities the properties of liquid crystal mixtures, especially chiral-smectic mixtures, favorably affect, for. B. in terms of dielectric anisotropy and / or melting point, however also with regard to the switching behavior, the values of the tilt angle or its Temperature dependence.

The invention therefore relates to furan 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 furan-2,5-diyl or furan-2,4-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 can;  
• e) in the case of a branched alkyl group with 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

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

- or -CH ₂

CH ₂

-
Z: a single bond
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 independent of each other undirected -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 linking to X or H CH ₂ groups. "Undirected" means the possibility of mirror-inverted installation of the group.

The following compounds of the formulas (I-1) to (I-16) 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 radical (with or without asymmetrical carbon atoms) with 1 to 16 carbon atoms,

The compounds of the formulas (I), in particular (I-1) to (I-16), in which R ³ and R ⁴ independently of one another denote a straight-chain alkyl radical having 2 to 16 carbon atoms, are particularly preferred.

Also particularly preferred are the compounds of the formulas (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} hydrogen or one is a straight-chain alkyl radical with 2 mean up to 12 carbon atoms.

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

• a) -C * H (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) C * H (CH ₃ ) OC _m H _{2m + 1} , where m has values from 1 to 10
• e) -OC (= O) C * H (F) C _m H _{2m + 1} , where m has values from 1 to 10
• f) -OCH ₂ C * H (F) C _m H _{2m + 1} , where m has values from 1 to 10
• g) -OCH ₂ C * H (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, are described.

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 furans 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, particularly preferably chiral-smectic (ferroelectric). In particular preferred is the use in ferroelectric liquid crystal mixtures which operated in ads with active matrix elements.

The use in mixtures for active matrix is very particularly preferred. LCDs in which the chiral-smectic liquid crystal layer is a monostable Trains mono-domain.

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 containing one, preferably smectic 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, for example, 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 5-Ethyl-furan-2-carboxylic acid [4- (5-undecyl-pyrimidin-2-yl) phenyl] ester

4.9 g of 4 - (5-undecyl-pyrimidin-2-yl) phenol, 1.4 g of 5-ethyl-2-furan carboxylic acid (produced by Perry et al., Appl. Organomet. Chem. 10, 389-392 (1996) Furan-2-carboxylic acid; Mp 90 ° C) and 2.1 g of dicyclohexylcarbodiimide stirred in 50 ml dichloromethane for 24 h at room temperature. After filtration, Distillation of dichloromethane, chromatographic purification (silica gel; Dichloromethane / heptane) and recrystallization from acetonitrile Obtained target compound as colorless crystals with the phase sequence X 80 (N62) I.

Analog is obtained

Example 2 5-Ethyl-furan-2-carboxylic acid [2-fluoro-4- (5-undecyl-pyridin-2-yl) phenyl] ester

with melting point 76 ° C.

Analogously to Example 1, the compounds (I-1) to (I-12) can be prepared.

Example 3 (5-ethyl-furan-2-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 4.9 g of 4 - (5-undecyl pyrimidin-2-yl) phenol and 5-ethyl-furan-2-ylmethanol (produced by LiAlH ₄ - reduction of 5 -Ethyl-furan-2-carboxylic acid methyl ester, which in turn can be obtained from the esterification of 5-ethyl-furan-2-carboxylic acid from Example 1). After 24 h at room temperature it is brought to dryness in a vacuum.

After chromatographic purification (silica gel, dichloromethane) and The target compound can be obtained by recrystallization.

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

The compounds of formula (I-16) can with the sequence 5-ethyl-furan-2-yl-methanol - 2-bromomethyl-5-ethyl-furan - 2-bromomethyl-5-ethyl-furan triphenylphosphonium salt - Wittig reaction 4- (5-R ³ -pyrimidin-2-yl) benzaldehyde - hydrogenation can be obtained.

Claims (7)

1. furan derivatives of the formula (I),
R ¹ -X- (A ¹ -M ¹ ) _a - (A ² -M ² ) _b -A ³ -YT- ZR ² (I)
where the symbols and indices have the following meanings:
T furan-2,5-diyl or furan-2,4-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 one adjacent CH ₂ group by -OC (= O) -;

R ^{2 is} hydrogen or a straight-chain or branched alkyl radical (with or without asymmetrical C atoms) with 1 to 20 C atoms, a non-terminal, not adjacent to the furan -CH ₂ group by -O- or -OC (= O ) - or -C (= O) O- can be replaced and / or one or more H atoms can be replaced by F.
X: a single bond, -O-, OC (= O) -, -C (= O) O- or -OC (= O) O-
Y: -OC (= O) -, -OCH ₂ - or -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 Formula (I) according to claim 1. 3. Liquid crystal mixture according to claim 2, characterized in that it Contains 0.01 to 80 wt .-% of one or more compounds of formula (I).   4. Liquid crystal mixture according to claim 2 or 3, characterized in that that it is ferroelectric (chiral smectic). 5. Liquid crystal mixture according to claim 2 or 3, characterized in that that it is nematic. 6. Ferroelectric switching and / or display device containing one Ferroelectric liquid crystal mixture according to claim 4. 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.