JPS6084273A - 2,3-dicyano-5-substituted pyrazine derivative - Google Patents

Abstract

NEW MATERIAL:The 2,3-dicyano-5-substituted pyrazine derivative of formula I (R is 1-9C alkyl or alkoxy; X is -O, -CH2 group of formula II, etc.). EXAMPLE:4-(trans-4-Propylcyclohexyl)benzoic acid 4-(2,3-dicyanopyrazinyl-5)phenyl ester. USE:Useful as a high-temperature liquid crystal component. It has broad nematic temperature range and excellent compatibility with other liquid crystal compounds, and raises the clear point of a Schiff-base or azoxy liquid crystal compound. Since the compound has large positive dielectric anisotropy (DELTAepsilon), it can remarkably decrease the driving voltage of a liquid crystal composition at a low dose. PREPARATION:The compound of formula I can be produced by (1) reacting 4-hydroxyacetophenone of formula III with an oxidizing agent, (2) reacting the reaction product with diaminomaleonitrile in a solvent, and (3) reacting the product with a carboxylic acid chloride in the presence of pyridine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel compound having positive dielectric anisotropy, and more particularly to a novel compound having positive dielectric anisotropy and a liquid crystal composition containing the same. Liquid crystal materials with positive dielectric anisotropy can be used in liquid crystal display devices that use nematic liquid crystals with twisted alignment, so-called TN-type cells, and can also be used in the application of the guest-host effect by adding appropriate pigment materials. It is also used in color liquid crystal display devices. These liquid crystal materials cannot be used as a single compound in terms of their performance, ie, liquid crystal temperature range, operating voltage, response performance, etc., for practical use. In reality, at present, products that can withstand use are obtained by mixing several types of liquid crystal compounds or non-liquid crystal compounds.

An object of the present invention is to provide a practically stable compound suitable for such purposes.

The present invention has a large positive dielectric constant anisotropy value, has a wide liquid crystal temperature range, and has a high stability of the nematic clearing point (N-I point). The present invention provides a novel liquid crystal compound. The present invention relates to a 2,3-dicyano-5-substituted pyrazine derivative represented by the general formula (wherein R represents an alkyl group having 1 to 9 carbon atoms or an alcogine group, and X represents -); There is a liquid crystal X-forming acid product containing it.

Although the compounds of the invention have a wide nematic temperature range,
Since the crystal-nematic point (C-N point) is high, this compound alone is not practical for use in display devices. However, because of its excellent compatibility with other liquid crystal compounds and its high nematic clearing point (N-I point), other liquid crystal materials such as ship bases, azoquines, benzoic acid phenyl esters, etc.
A type of liquid crystal such as cyclohexanecarboxylic acid phenyl ester type, cyclohexanecarboxylic acid cyclohexyl ester type, biphenyl type, phenylclohexane type, phenylpyrimidine type, phenylmetadioxane type, etc.
Alternatively, by mixing it with a mixture of several types, the clearing point can be raised.It is useful as a so-called high-temperature liquid crystal component. Compared to liquid crystal materials such as lylcyclohexane, the dielectric constant anisotropy value (△ε
) is larger when using the compounds of the present invention, and smaller due to the use of the compounds of the present invention.
: However, the driving voltage of the liquid crystal composition can be significantly lowered.

The compound of the present invention having such excellent characteristics can be produced by the following reaction.

(C), (D) First, 4-hydroxyacetophenone (A) is suitable. Next, (13) and diaminomaleonitrile (C) are reacted in a suitable inert organic solvent such as tetrahydrofuran to remove the phenol derivative (D).

Next, add the corresponding carboxylic acid chloride in the presence of pyridine (
By reacting with D), the target compound (1) can be obtained.

The method for producing the compound (1) of the present invention and its application examples will be explained in detail in Examples (2) below.

Hereinafter, the crystal-nematic transition point will be abbreviated as the C-N point, the nematic-clearing point as the N-1 point, and the crystal-clearing point as the C-I point.

Example 1 4-()Lance-4-propyrunchlorohexyl)benzoic acid 4-(2,3-dicyanopyrazinyl-5)phenyl ester (1) Production of 4-hydrogin phenylglyoxal hydrate Selenium dioxide 11,11 (0°1 mol) was added to a mixed solution of p-dioxane 5 Q cc and water Qec at 60°C.
The mixture was heated and dissolved. Next, 13.6 F (0.1 mol) of 4-hydroxyacetophenone was added all at once, and the mixture was heated and reacted under rapid flow for 4 hours. After the reaction was completed, the precipitated inorganic substances were washed away, and p-dioxane was distilled off from the liquid f. 80 cc of water was added to the reddish-brown oil, and the mixture was heated and stirred at 80° C. for 2 hours. After the reaction was completed, the precipitated crystals were allowed to cool to room temperature, separated by dj, and dried.
Obtained the objective. Melting point: 109-111″c.

(2) 4-Hydroxyphenylglyoxal hydrated q3Ae obtained in the production of 4-(2,3-zineanopyrazinyl-5)phenol (]). 6f (0,057 mol), and diaminomaleonitrile 6.2 f (0,057 mol)
was dissolved in 20 cc of tetrahydrofuran, and the mixture was stirred at room temperature for 6 hours. After the reaction was completed, tetrahydrofuran was distilled off from the reaction mixture, and the remaining solid was recrystallized from 50 cc of ethanol to obtain the desired product with a molecular weight of 7.72 mm.

Melting point: 204-205°C.

(3) 4-()lans-4-propyruncloheginyl)benzoic acid 4-(2,3-zineanopyrazinyl-5
) Preparation of phenyl ester Two parts of thionyl chloride were added to 1f of 4-(trans-4-propyrunchlorohexyl)benzoic acid, and the mixture was reacted under reflux for 2 hours. After the reaction was completed, excess thionyl chloride was distilled off to obtain acid chloride. On the other hand, the acid chloride obtained earlier was added to a solution of 4-(2,3-ginanopyrazinyl-5)phenol 1f obtained in (2) dissolved in dry pyridine 3ce, and the mixture was heated at 60°C. The reaction was heated for 3 hours. After the reaction was completed, the reaction product was poured into 10 Q cc of water, and the precipitated crystals were extracted with 1 Q cc of toluene. The extract was washed with dilute salt solution, dilute aqueous sodium hydroxide solution, and then water, and the toluene layer was dried over anhydrous sodium sulfate. Subsequently, toluene was distilled off, and the remaining solid material was recrystallized from 5 cc of benzene to obtain a solid product on January 1, 12. C-N point; 164.
8-165.3°C, N-I point; 273°C.

Examples 2-4 The following compound was synthesized by a method similar to Example].

4-Butylbenzoic acid 4 (2+3-dinanopyrazinyl-5) phenyl ester C-I; 123°C 4-pentyloxybenzoic acid 4. -(2,3-Zinanopyrazinyl-5)phenyl ester C-I; 126.4
~1.2 'i', 2°C N-I; 123.5~], 2
3.8℃ trans-4-()trans-4-propylenechlorohexyl)chlorohexanecarboxylic acid 4-(2,3
-Zinanopyrazinyl-5) Phenyl ester C-N; 1 65.7-166°9°C N-I;
The nematic temperature range of the tfk product composition with a proportion of 2'i'8.1°C is -5 to 52°C. Cell thickness of this liquid crystal composition] Oμm
The operating threshold voltage of the TN cell sealed in is 1.5.
4 V, and the saturation voltage was 2.13 V. Also sticky IW
was 23.5 cP at 20°C.

4-(trans-4-propylcyclohexyl)benzoic acid 4-(2,3- The nematic liquid crystal temperature range of the liquid crystal composition containing 5 parts of zineanopyrazinyl-5) phenyl ester is -5°C.
It was ~59°C.

This is sealed in a TN cell with the same cell thickness as above, 10) ttn.The operating threshold voltage is 20V, and the saturated Ichikawa voltage is 1. It was significantly improved to 82V. Also, the viscosity is 2 at 20℃.
It was 5 CP.

Above 111' 1 wa gi ((person Chisso Co., Ltd.
The patent was filed on April 77, 1159 by the company, Kazuo Wakasugi. Substituted pyrazine = Bb body 3, sleeve 1
Relationship with the case of a person who commits 1 mi Patent applicant: Kita 1, Osaka City, Osaka Prefecture Nakanoshima 3-chome 1 T46 Flea No. 82 (〒5
30) (207) Chisso Corporation Representative Sada Nogi Ha1: 4, Agent 2-8-1, 1r-Shuku, Shinjuku-ku, Tokyo (160) 6,
No increase in the number of inventions due to amendments 7, Ner. 4 Correct Claims of the subject specification and each column of detailed description of the invention 8 Answers for amendments (1) Separate claims of the specification Correct as follows.

(2) Re-write details 8th line 1θ line, “273℃” 1'-2
78,0°C”.

(3) Line 16 of Dokuma Pagi, “123°nJ” is “122.
5-12 a, o℃" and 6 IEs.

(4) Same practice, page 9, line 6, “278.1°le”2
77.8~278.1 'Corrected as CJ.

(5) Doheki: Between the 6th line and the 7th line of Dosei, it is written as ``Shiku Legends 5-9 The following five compounds were synthesized by a method similar to Example 1.''

Butyl-4-(2,3-dicyanopyrazinyl-5)phenyl carbonate.

Pentane r&4-(2,8-dicyanopyrazinyl-5)
Phenyl ester.

trans-4-propylcyclohexanecarcibon 4
f-(2,8-dicyanopyrazinyl-5)phenyl ester, I trans-4-(4-7”f-ruphenyl)cyclohexanecarvone+4&4-(2,3-dicyanopyrazinyl-
5) Phenyl ester.

4-(4-Pentylphenyl)amino-3': Ifi11 wave 4-(2,a-dicyanopyrazinyl-5)7enyl ester.

The phase transition points of these compounds are shown in No. 124 along with the results of practical hfq Examples 1 to 4.

In Table 1, C, N, and I of persimmon at the phase transition point are crystals, respectively.
The phase difference of the nematic liquid crystal and isotropic liquid is shown, and the symbol in the lower column indicates the presence of the upper %2 phase. machete, (
) indicates the monotropic transition point. ” (insert).

9. Attachment 4 q lhOMk-'f's'WF between jlllx of the claim (total The alkyl group also represents a frt alkoxy group, where X is 10-1-CH. 2,3-dicyano-5-substituted virazine derivatives.

(2) General formula (wherein R represents an alkyl group or alkoxy group having 1 to 9 carbon atoms, or X□□□4←)
, a 3-dicyano-5-substituted pyrazine aggregate.

that's all

Claims (2)

[Claims] (1) General formula (in the formula, 1 represents an alkyl group or an alkoxy group having 1 to 9 carbon atoms, and X is
A 2,3-dineano-5-substituted pyrazine derivative represented by (representing aX). (2) General formula (wherein R represents an alkyl group or alkoxy group having 1 to 9 carbon atoms, and X contains a 2,3-dicyano-5-substituted pyrazine derivative represented by complement-1) A liquid crystal composition.