JPS60260653A - Benzo(thio)xanthene compound and liquid crystal composition containing it - Google Patents

Abstract

NEW MATERIAL:A benzo(thio)xanthene compound of formula I, where X is O or S; R<1> is an alkyl, an alkoxy, benzyloxy, a trans-4-alkylcyclohexyl(alkyloxy), an alkylamino or a heterocyclic group; R<2> is a trans-4-alkylcyclohexylalkyl, a group of formula II (where R<3> is an alkylene; R<4> is benzyloxy or a trans-4- alkylcyclohexylalkyloxy), etc. USE:A dichroic dye used for a liquid crystal composition of guest-host effect type (having a high dichroic ratio and excellent solubility in a liquid crystal). PREPARATION:A compound of formula III is diazotized with sodium sulfite, etc. and then decomposed with copper sulfate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel benzo(thio)xanthine compound and a liquid crystal composition containing the compound. , 11 7 [Prior art] Conventionally, a liquid crystal 3-crystalline paraboloid formed by dissolving a dye compound in a liquid crystal is interposed between two opposing electrodes to create a guest-host effect between the dye compound and the liquid crystal. It is known that color display can be performed by using this method.

The dye compound used in such a liquid crystal composition is particularly suitable for λ
It is necessary to have properties such as a high chromaticity ratio and high solubility in liquid crystals.

The present inventors conducted studies focusing on benzo(thio)xanthine compounds in order to provide a dye compound having the above properties and exhibiting a yellow to orange hue.

Various benzo(thio)xanthine compounds have been known in the past, but they were mostly used as dyes for fibers such as polyester fibers (Tokuko Showa-atto, Tokko Shosan). J-33! J11 Special Public Service 1973-Star).

However, according to the studies of the present inventors, benzo(thio)xanthin compounds, conventionally known as dyes for textiles, are not necessarily required as dye compounds used in liquid crystal compositions as described above. It has been found that these compounds do not satisfy such properties as those described above, and that they cannot be immediately applied as dye compounds for liquid crystal compositions.

[Purpose of the invention]

Therefore, as a result of further studies, the present inventors found that a specific benzo(thio)xanthin compound exhibits a high cochromaticity ratio and good solubility in liquid crystals, and is capable of producing liquid crystals with good color display. The present invention was completed based on the knowledge that the present invention can provide a composition.

That is, the object of the present invention is to provide a compound of the general formula (1) [wherein, X represents an oxygen atom or a sulfur atom, and R1 is an alkyl group; a penzyloxy group that may be substituted; a trans-≠-alkylcyclohexyl group; a trans-μm alkylcyclohexylalkyloxy group; an alkylamino group that may be substituted with an alkoxy group;
) represents a trans-V-alkylcyclohexyl akylene group; R4 represents a benzyloxy group which may be substituted with an alkyl group or an alkoxy group; a trans-V-alkylcyclohexylalkyloxy group; ); cyclohexyl group; benzyloxy group optionally substituted with an alkyl group or alkoxy group; benzylamino group optionally substituted with an alkyl group or alkoxy group; trans-gualkylcyclohexyl Alkyloxy group; trans-l-alkylcyclohexylalkylamino group; trans-Hiro-alkylcyclohexyloxycarbonyl group; alkylphenyl group:
Indicates an alkoxyphenyl group. ) represents a group. An object of the present invention is to provide a benzo(thio)xanthine compound represented by the following formula and a liquid crystal composition containing the compound.

[Structure of the invention]

The benzo(thio)xanthine compound of the present invention is represented by the general formula (1).

In the formula, R1 is an alkyl group having 1 to 13 carbon atoms; an alkoxy group having 1 to 3h4 carbon atoms, which may be substituted with an alkoxy group having 1 to 13 carbon atoms; an alkyl group having 7 g carbon atoms, etc. or a benzyloxy group which may be substituted with an alkoxy group having 1 to 1 carbon atoms; trans-t-alkyl (for example, alkyl having 1 to 1 carbon atoms); cyclohexyl group; trans-μm alkyl (for example, carbon alkyl having a number of 1A-t) cyclohexylalkyl (e.g., alkyl having 7 carbon atoms)
~ j alkyl) oxy group+11 is substituted with an alkoxy group having carbon number/-1, carbon number/-4 which may be 0! @ indicates a monoalkyl or 9-dialkylamino group; a heterocyclic residue such as a piperidine group or a 1 mol polyy group.

Further, R1 represents an alkylene group such as trans-gualkyl (e.g., alkyl having carbon number/~l), cyclohexylalkyl (e.g., alkyl j having carbon number/~it), and R4 represents an alkyl group having carbon number/-r, etc. Group or number of carbon atoms/
Benzyloxy group optionally substituted with an alkoxy group such as -4; trans-μm alkyl (for example, carbon number /
~t alkyl) cyclohexylalkyl (e.g. carbon number/-j alkyl) oxy group R1 is trans-μm
Alkyl (for example, alkyl having 1 to t carbon atoms) cyclohexyl group;
A pen/zyloxy group optionally substituted with an alkoxy group such as -J'; an alkyl group having a number of 1 to 1 carbon atoms, or a benzyloxy group optionally substituted with an alkoxy group having 1 to 8 carbon atoms; Group; trans-synthene-alkyl (e.g.
alkyl having carbon number/-4) cyclohexylalkyl (e.g. alkyl having 7 to j carbon atoms) oxy group; trans-
Trans-alkyl (e.g., alkyl having carbon number/-4) cyclohexyl alkyl (e.g., alkyl having carbon number/-j); amino group; trans-alkyl (e.g., alkyl having carbon number/-1) cyclohexyl Ox7carbonyl group; number of carbon atoms / alkyl-substituted phenyl group such as ~; number of carbon atoms /
-1 represents an alkoxy-substituted phenyl group. ] represents a group.

In addition, the above-mentioned alkyl group or alkoxy group having 3 or more carbon atoms may be linear or branched.

The benzo(thio)xanthine compound represented by the general formula [1] can be synthesized, for example, by the following method described in Japanese Patent Publication No. 4 Ip-ptto.

Furthermore, when the substituent R1 is an alkylamino group, Tokko Sho! 3-3g? It can also be synthesized by the following method described.

(N) (V) (1) In the above general formulas (1) to (V), X, R1 and R1 have the same meanings as above.

The nematic liquid crystal used in the present invention can be selected from a wide range as long as it exhibits a nematic state within the operating temperature range.

Further, by adding an optically active substance to be described later to such a nematic liquid crystal, it can be made to take a cholesteric state. Examples of nematic liquid crystals include the substances shown in Table 1 or derivatives thereof.

Table 7 11-12- In the above table, R' represents an alkyl group or an alkoxy group,
represents a nitro group, a cyano group, or a halogen atom.

All of the liquid crystals in Table 1 have positive anisotropy, but known ester threads, azoxy-based, azo-based, and
Schiff type, pyrimidine thread.

Diester or biphenyl ester liquid crystals are also available.
It can be mixed with a liquid crystal having positive dielectric anisotropy to form a positive liquid crystal as a whole.

Further, even a liquid crystal having negative dielectric anisotropy can be used as is if an appropriate element configuration and driving method are used.

The host liquid crystal material used in the present invention may be any of the liquid crystals shown in Table 1 or a mixture thereof, but the following 4 is a mixture of glazed liquid crystals,
, 2 and the following ≠
Br1tish Drug House as a mixture of citrus liquid crystals
A liquid crystal sold by E Company under the trade name E-7 is particularly useful in the present invention.

The optically active substance used in the present invention is a chiral nematic compound, for example, an optically 15-active group such as a 2-methylbutyl group, a 3-methylptoxy group, a 3-methylpentyl group, a 3-methylpentoxy group, a 4-methylbexyl group, a V-methelhexyl group, etc. There is a compound that has been introduced into nematic liquid crystal. In addition, t-menthol, d-
Alcohol derivatives such as borneol, d-camphor,
Ketone derivatives such as 3-methylcyclohexane, carboxylic acid derivatives such as d-citronellaic acid and 1-camphoric acid, d
- Optically active compounds such as aldehyde derivatives such as citronellal, alkene derivatives such as d-linonene, and other amine, amide, and nitrile derivatives can be used.

As an element for performing liquid crystal display using the liquid crystal of the present invention, a known liquid crystal display element can be used. That is,
In general, transparent electrodes in an arbitrary pattern are provided on two glass substrates, at least one of which is transparent, and the device is placed so that the two glass substrates are parallel to each other with an appropriate spacer interposed so that the electrode surfaces face each other. The configured one is used.

In the case of nickel, the gap between the elements is determined by the spacer. As the element gap, F13~100μm%, especially S
-S Oμm is preferable from a practical standpoint.

〔Effect of the invention〕

The benzo(thio)xanthine compound of the present invention exhibits good solubility in liquid crystal, and the obtained liquid crystal composition has a high λ color ratio, so that clear color display is possible.

〔Example〕

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

The order parameter representing the λ chromaticity ratio will be explained below. The order parameter S of the dye compound can be determined experimentally from the following equation.

Artificial+AI Here, AI and AJL are the absorbances of the dye for light polarized parallel to and perpendicular to the alignment direction of the liquid crystal, respectively.

Order-9 parameter B is specifically a value indicating the display contrast of the guest-host type liquid crystal element, and the closer this value is to theoretically /, the less the residual color in the white area decreases.
A bright and clear display with high contrast is possible.

Example/) A compound represented by the following structural formula /, /It is dissolved in acetic acid and concentrated hydrochloric acid-211IeK, added with JOml of water, and cooled to OC. An aqueous solution of 0.212 sodium nitrite is added to this solution and stirred at 0-jC for 2-3 hours. Copper sulfate j hydrate 1. Dissolve riiy in water, 20IIIK, riO~rij
Heat CK. The above aqueous solution is added to this solution under stirring and the reaction mixture is stirred for 2 hours at 10°C.

The precipitated crystals were filtered and dried, and impurities were separated and purified by column chromatography using silica gel (manufactured by Wako Pure Chemical Industries, Ltd.; o-, 2oo product names) as a carrier and chloroform as a separation solvent, resulting in the following structure. A compound represented by the formula /20■ was obtained. This compound is -203
It showed a melting point of ~20 tlT. The obtained compound was converted into the above-mentioned phenylcyclohexane y4 mixed liquid crystal ZLI-//J, 2
The compound (dye) was dissolved by repeating the steps of heating the liquid crystal to 70C or higher to turn the liquid crystal into an isotropic liquid, stirring well, and then leaving it to cool.

The above-mentioned liquid crystal composition prepared in this manner was coated with a polyamide resin on the surface in contact with the liquid crystal, coated with a polyamide resin, and rubbed after hardening to form a homogeneous, upper and lower two-layer structure that had been subjected to a homogeneous alignment treatment.
The device was sealed in a device consisting of two glass substrates with an inter-substrate gap of IO μm. In the device subjected to the alignment treatment, the liquid crystal was in a homogeneous alignment state when no voltage was applied, and the dye molecules were also aligned in the same manner according to the host liquid crystal.

The absorption spectrum of the guest-host device thus prepared was measured using light polarized parallel to the alignment direction of the liquid crystal molecules and light polarized perpendicularly to the orientation direction of the liquid crystal molecules.
The maximum absorption wavelength of the dye for each of these polarized lights was determined.

In calculating the absorbance of the dye, corrections were made for absorption by the host liquid crystal and glass substrate and reflection loss of the element.

Also, using A/ and A soil for each polarization, the above formula %formula% The value of order parameter B was calculated from .

The above results are shown in Table 4 (A/)K below.

20-λ) Compound 0. J iG t to 20 tril acetic acid
Dissolve jfC and add 0.0% concentrated hydrochloric acid. Add 10 vil of water and cool to OC. Add sodium nitrite 0, O to this solution.
Add an aqueous solution of ff and stir at o-jC for 2-3 hours. Dissolve 0.71 rt of copper sulfate in 0.1 ml of water and heat to 0 to 100 ml. The above aqueous solution is added to this solution under stirring, and the reaction mixture is stirred for 2 hours in a to-ta OC. The precipitated crystals were filtered and dried, and impurities were separated and purified by column chromatography using silica gel (manufactured by Wako Pure Chemical Industries, Ltd.; C-200 product name) as a carrier and chloroform as a separation solvent, and the following structural formula was obtained. I have looked at the compound shown by θ■. This compound -j♂, θ~
It showed a melting point of 26t, θC. The present compound was dissolved in the above-mentioned phenylcyclohexane thread mixed liquid crystal Zl, Ni//32 in the same manner as the compound obtained in step 1) above, and the maximum absorption wavelength and order parameter S were calculated.
I showed it to Seller 3.

The compounds shown in Table 2 below were produced by the same procedure as above, and the maximum absorption wavelength and order parameter (S) of the isolated compound were measured by the same procedure as above. The results were shown. (However, minutes indicate trans-cyclohexyl.)

Claims (2)

[Claims] (1) General formula (1) [In the formula, X represents an oxygen atom or a sulfur atom, and R1 is an alkyl group; good benzyloxy group; trans-V-alkylcyclohexyl group; trans-Hiro-alkylcyclohexylalkyloxy group; alkylamino group which may be substituted with an alkoxy group; represents a heterocyclic residue, R2 is trans-t -Alkylcyclohexylalkyl group; R4 represents a benzyloxy group which may be substituted with an alkyl group or an alkoxy group; trans-II-alkylcyclohexylalkyloxy group; ): a group represented by the formula cyclohexyl group: a benzyloxy group optionally substituted with an alkyl group or an alkoxy group;
Benzylamino group optionally substituted with an alkyl group or alkoxy group; trans-l-alkylcyclohexylalkyloxy group; trans-alkylcyclohexylalkylamino group; trans-+-furkylcyclohexyloxycarbonyl group ; Alkylphenyl group; Indicates an alkoxyphenyl group. ) represents a group. ] A benzo(thio)xanthine compound represented by (2) General formula (1) [In the formula, X represents an oxygen atom or a sulfur atom, and R1 represents an alkyl group; a benzyloxy group which may be substituted with an alkoxy group; a trans-gualkylcyclohexyl group; a trans-V-alkylcyclohexylalkyloxy group; an alkylamino group which may be substituted with an alkoxy group: a heterocyclic residue, and HR represents a trans- t-alkyl (wherein Ha represents an alkylene group,
R4 is a benzyloxy group optionally substituted with an alkyl group or an alkoxy group; trans-≠-alkylcyclohexylalkyloxy group;
≠-alkylcyclohexyl group; benzyloxy group optionally substituted with an alkyl group or alkoxy group; benzylamino group optionally substituted with an alkyl group or alkoxy group; trans-≠-alkylcyclohexylalkyloxy group; trans-p-alkylcyclohexylalkylamino group; trans-alkylcyclohexyloxy carbonyl group: alkylferol group;
'ylkoxyphenyl group. ) indicates the group represented. ] A liquid crystal composition containing a benzo(thio)xanthine compound represented by: