JPS6151062A - Anthraquinone compound and liquid crystal composition containing same - Google Patents

Abstract

NEW MATERIAL:Compounds of formula I wherein Y is H when X is NH2 and Y is H, OH when X is OH; R1 is H, F, Cl, CN, CH3, C2H5O, etc.; R2 is H, F, Cl, Br, CN, CF3, unsubstituted or cyclohexyl(oxy) or phenyl-substd. 1-12C alkyl or alkoxy, a group of formula II or III, etc.; R3 is H, CH3, phenyl; R4 is a 1-4C alkyl; one of R5, R6 is H or R4 and the other is R4; R7 is a 2-9C alkyl where at least three H atoms are substituted with F; m is 0-2; n is 0-3. EXAMPLE:Compound of formula IV. USE:Yellow to red anthraquinone compds. for liquid crystal compsn., which have excellent dichroism. PREPARATION:1mol of an anthraquinone compd. of formula V (wherein Z is Cl, Br) is reacted with at least 2mol of a phenol derivative of formula VI in the absence or presence of a solvent (e.g. N-methylpyrrolidone) and in the presence of an acid acceptor (e.g. K2CO3) at 100-250 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a novel anthraquinone compound and a novel anthraquinone compound useful as a dye for the same.

``Prior art'' A method for displaying by sandwiching a nematic or cholesteric liquid crystal containing dichroic dyes with positive or negative dielectric anisotropy between two electrodes and applying a voltage is known as Gestoho's 7T display element. is already known as.

This display element has (1) a wider viewing range than twisted nematic (TN) elements used in calculators, watches, etc.;

(2) Great degree of freedom in selecting hue.

(3) The number of polarizing plates used is reduced.

(4) Cost can be reduced.

There are advantages such as

This guest-host display element changes the molecular alignment direction of the dichroic dye and changes the absorption of light passing through the liquid crystal layer to display the display.Since this is a 50,000-row system, the dichroic dyes used are as follows. It is necessary to satisfy the following items. That is, (1) It should be dissolved in the host liquid crystal to an extent that a practical coloring density can be obtained.

(2) Dogs and other animals exhibit dichroism that contributes to display contrast.

Although such dichroic dyes can be used alone, multicolor displays using light shutters created by dissolving black-based dyes obtained by blending various dyes into liquid crystals have been put to practical use in automobiles. ing.

Conventionally, among the components of black-based pigments, azo pigments have been used for colors from yellow to red, and anthraquinone pigments have been used for blue colors.

However, although the solubility and dichroism of azo dyes are at good levels, the light fastness is at a somewhat insufficient level for use in automotive applications. Furthermore, among the anthraquinone dyes, which generally have better light fastness than azo dyes, there are few known anthraquinone dyes that have good solubility and dichroism and exhibit a yellow to red hue.

"Problems to be Solved by the Invention" Most of the yellow to red pigments used alone as pigments for guest-host type liquid crystal display elements or as a compounding component of black pigments are azo compounds, and it is necessary to use them for automotive applications. It is difficult to say that the light fastness is at a sufficient level when used for purposes such as the following.

Therefore, it is desired to develop an anthraquinone compound that has better light fastness than azo compounds, has a yellow to red hue, and has good solubility and dichroism.

"Means for Solving the Problems" The present inventors have made extensive efforts to develop anthraquinone dyes for guest-host type liquid crystal display devices that exhibit a yellow to red hue and have good solubility, dichroism, and light fastness. As a result of research, I found that the formula (I) (wherein, when X is amine, Y represents hydrogen; when X is hydroxy, Y represents hydrogen or hydroxy. , methyl, ethyl, methoxy, ethoxy representation, R2
is hydrogen; fluorine: chlorine; bromine trifluoromethyl; cyclohexyl, cyclohexyloxy, phenyl, alkyl or alkoxy of Cl5C12 optionally substituted with phenoxyte (in which the carbon chain is interrupted by 1 to 3 oxygen atoms) ) ; (CzH
a O) mcHz-(); - represents p or -ORt. and s Rs represents hydrogen, methyl or phenyl, and R4 represents alkyl of 01-4.几5. One of R6 represents hydrogen or alkyl of 01-4, and the other represents Ct-4
represents an alkyl. Further, R7 represents an alkyl group of 02 to 9 in which at least three or more hydrogen atoms are substituted with fluorine, m represents 0.1 or 2, and n represents O, 1, 2 or 3. ] The present invention was completed by discovering that a novel anthraquinone compound represented by the following has these properties.

The anthraquino/compound represented by the formula (Il) of the present invention can be synthesized by various methods, one example of which is shown below.

Formula ■ [In formula ■, X and Y represent the same meanings as above, and 2 represents chlorine or bromine. ] An anthraquinone compound represented by the formula (Saraya HO8 & (ffl) Alternatively, when X is hydroxy and Y is hydrogen in the formula (Il), the formula (
[V] [In the formula, Rs and R2 have the same meanings as above.

] The amino group of an anthraquinone compound represented by the formula (), when X is amino and Y or hydrogen is - [2M, 几1#R2 represents the same meaning as above. ] It can be synthesized by diazotizing one of the amino groups of an anthraquinone compound represented by the formula and then dediazotizing it.

Specific examples of solvents optionally used when reacting compounds of formula I and compounds of formula (III) include N
-Methylpyrrolidone, N,N-dimethylformamide,
Examples include dimethyl sulfoxide. In addition, examples of acid binders to be allowed to coexist when the compound of 2I and the compound of formula ■Anthraquino/Compound 1
The amount is 2 moles or more, preferably 2 to 3 moles.

The reaction temperature when the compound of formula (1) and the compound of formula (ffl) are reacted in the presence of an acid binder without a solvent or in a solvent is 100 to 250°C, preferably 1205200°C.

To synthesize a compound of formula (I) from a compound of formula ([V) or formula M, the compound of formula (rV) or 2M is diazotized with sodium nitrite in a solvent such as sulfuric acid or acetic acid to obtain the compound of formula (I). The obtained diazonium salt is added to a solvent such as ethanol, ingropanol or dimethylformamide and dediazotized at 50 to 100°C, or it is diazotized with isoamyl nitrite in dimethylformamide for 30 to 10 minutes.
This is achieved by heating to 00°C.

The anthraquinone compound represented by formula (I) of the present invention is used as a dichroic dye, but when preparing a liquid crystal composition, one or more of these compounds are added to the host liquid crystal in an amount of 0.01 to 25% by weight, preferably 0.1-5
It can be used by adding % by weight. The compound of the present invention can be blended with other dichroic dyes to be used as a black blended dye, and furthermore, other optically active substances may be used in combination with the liquid crystal composition of the present invention.

As the host liquid crystal compound used in the liquid crystal composition of the present invention, piphenyl-based, phenylcyclohexane-based, ester-based, pyrimidine-based, dioxane-based, Schiff-based, azo-based, and azoxy-based liquid crystals are used.

The liquid crystal may be nematic, twisted-nematic, cholesteric nematic phase transition type, smectic, etc., and the display method may be any method based on the positive or negative dielectric anisotropy of the liquid crystal.

"Example" The present invention will be explained in more detail with reference to Examples below. In the examples, "parts" means parts by weight.

Example 1 21.5 parts of p-11-butylphenol and 1.5 parts of potassium carbonate are heated to 150 DEG C. in a nitrogen stream to dehydrate them.

Then, the mixture was cooled to 100°C, 4.1 parts of 1-amino-4,8-dihydroxy-3,7-dipromanthraquinone was added, the temperature was raised to 180°C, and the mixture was reacted at the same temperature for 5 hours.

After the reaction is completed, the mixture is cooled to 70°C, 30 parts of methanol is added, and the precipitated crystals are separated, washed with methanol and water, and then dried. When the obtained crude product was purified by column chromatography, two parts of the dye of the following formula were obtained.

Melting point 213 to 214.5°C λmax 528 + 564 nm (in xylene) The acetone dissolution color of this dye was red.

The obtained dye was placed on a liquid crystal ZLI-1565 manufactured by Merck.
% and subjected to homogeneous alignment treatment are sealed in a cell facing each other at a distance of about 10 ropes, and when the voltage is turned on and on, a good contrast is obtained, and the dichroic ratio is It was 10.5. Also, the solubility of this dye in liquid crystal (5% in liquid crystal E-8 manufactured by Merck & Co.)
(dissolution, room temperature) and light fastness were good.

Example 2 20 parts of N-methylpyrrolidone, 10 parts of p-n-butylphenol, and 1.6 parts of potassium carbonate were mixed in a nitrogen stream for 15 minutes.
The temperature is raised to 0°C and dehydration is performed. The mixture was then cooled to 100°C, 4.3 parts of 1.4.5.8-tetrahydroxy-3,7-dipromanthraquinone was added, the temperature was raised to 170°C, and the mixture was reacted at the same temperature for 5 hours.

After the reaction is completed, the mixture is cooled to 70°C, 25 parts of methanol is added, and the precipitated crystals are separated, washed with methanol and water, and then dried. The obtained crude product was purified by column chromatography to obtain 2.5 parts of a dye of the following formula.

Melting point 248-251'C: λmax 521 + 558 nm (in xylene) The acetone dissolution color of this dye was red. It was confirmed by mass spectrometry that the target compound was produced.

The obtained dye was placed on a liquid crystal ZLI-1565 manufactured by Merck.
% was added and sealed in a cell in the same manner as in Example 1, and when the voltage was turned on and off, a good contrast was obtained and the dichroic ratio was 8.0.

Furthermore, this dye had good solubility in liquid crystal and excellent light resistance.

Example 3 5.7 parts of the compound of the following formula was added to 70 parts of dimethylformamide and stirred for 1 hour, then the temperature was raised to 50'GK, and at the same temperature 7 parts of isoamyl nitrite was added, and the mixture was heated to 30°C at 50-55°C. Allow time to react. After the reaction is complete, the reaction solution is poured into ice water, filtered, washed with water, and dried. The obtained crude product was purified by column chromatography to obtain 2.9 parts of the dye of the following formula.

Melting point 194-196°C λmax 496 * 520 nm (in xylene) The acetone solution color of this dye was yellow-orange.

When the obtained dye was added at 1% to ZLI-1565 manufactured by Merck and sealed in a cell and the voltage was turned on and off, a good contrast was obtained and the dichroic ratio was 8.0.

Moreover, this dye had excellent solubility in liquid crystal and light resistance.

Examples 4 to 125゜ An anthraquinone compound represented by the formula (Il) was synthesized and a liquid crystal composition was prepared in the same manner as in Examples 1 to 3. 1 Table 1
~3 shows the structural formula of the anthraquinone compound represented by the formula (VD ~) and the λma expressed.

Table 1゜U Ul-1 Table 2゜1-1 (J U Ul-1 Table 3゜Note 1 C Table 1 to Table 3): Tripolymerity of propylene 2
(Table 1) ° #4 Polymer "Effects of the Invention" A yellow to red anthraquinone compound was obtained which showed excellent solubility in liquid crystal substances and excellent dichroism. This product also has good light fastness, so it has extremely high utility value in preparing liquid crystal compositions.

Claims (2)

[Claims] (1) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In formula (I), when X is amino, Y is hydrogen, and when X is hydroxy, Y is hydrogen or hydroxy. represent Also, R_1 is hydrogen, fluorine, chlorine, cyano, methyl, ethyl, methoxy or ethoxy, and R_2 is hydrogen; fluorine;
Chlorine; Bromine; Cyano; Trifluoromethyl; C_1-C_1_2 alkyl or alkoxy optionally substituted with cyclohexyl, cyclohexyloxy, phenyl, phenoxy (in which the carbon chain is interrupted by 1 to 3 oxygen atoms) (may be) ;-(C_2H_4O)mC
H_2CH=CHR_3;-O(C_2H_4O)mC
H_2CH=CHR_3;-(CH_2)nCOOR_
4;-COR_4;-NHCOR_4;-NHCOOR
＿４；▲There are mathematical formulas, chemical formulas, tables, etc.▼;▲There are mathematical formulas, chemical formulas, tables, etc.▼;▲There are mathematical formulas, chemical formulas, tables, etc.▼;▲There are mathematical formulas, chemical formulas, tables, etc.▼ or -OR
Represents _7. And R_3 represents hydrogen, methyl or phenyl, and R_4 represents alkyl of C_1_-_4. One of R_5 and R_6 represents hydrogen or alkyl of C_1_ to_4, and the other represents alkyl of C_1_ to_4. Furthermore, R_7 is m
represents 0, 1 or 2, and n represents 0, 1, 2 or 3. ] An anthraquinone compound represented by (2) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In formula (I), when X is amino, Y represents hydrogen; when X is hydroxy, Y represents hydrogen or hydroxy. . Also, R_1 may be hydrogen, fluorine, chlorine, cyano, methyl, ethyl, methoxy, or ethoxy, and R_2 may be substituted with hydrogen; fluorine; chlorine; bromine; cyano; trifluoromethyl; cyclohexyl, cyclohexyloxy, phenyl, or phenoxy. -(C_2H_4O)mCH
_2CH=CHR_3;-O(C_2H_4O)mCH
_2CH=CHR_3;-(CH_2)nCOOR_4
;-COR_4;-NHCOOR_4;▲There are mathematical formulas, chemical formulas, tables, etc.▼;▲There are mathematical formulas, chemical formulas, tables, etc.▼;▲There are mathematical formulas, chemical formulas, tables, etc.▼;▲There are mathematical formulas, chemical formulas, tables, etc.▼ Or represents -OR_7. And R_3 is hydrogen, methyl or phenyl, R_4 is C_
Represents an alkyl group of 1_ to _4. One of R_5 and R_6 represents hydrogen or alkyl of C_1_ to_4, and the other represents alkyl of C_1_ to_4. Furthermore, R_7 is C in which at least three or more hydrogens are replaced with fluorine.
m represents 0, 1 or 2, and n represents 0, 1, 2 or 3; A liquid crystal composition containing one or more anthraquinone compounds represented by the following.