JPH04169573A - Pyrimidine derivative, liquid crystal composition containing the derivative and liquid crystal display element produced by using the same - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R is 1-10C alkyl; A is single bond, 1,4-phenylene or group of formula II ; the configuration of cyclohexane ring is trans). EXAMPLE:2-(3',5'-Difluoro-4'-chlorophenyl)-5-butylpyrimidine. USE:A liquid crystal display element. The compound remarkably lowers the threshold voltage without deteriorating electrooptical properties (alpha value and betavalue) and is useful as a principal component of a liquid crystal composition for supertwisted nematic display. PREPARATION:The objective compound of formula I can be produced by reacting a compound of formula III derived from 2,6-difluoroaniline with a compound of formula IV or formula V in ethanol in the presence of metallic sodium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel pyrimidine derivative used as an electro-optical display material, a liquid crystal composition containing the same, and a liquid crystal display element using the same.

[Summary of the invention]

The present invention is based on the general formula (in the above formula, R represents a straight chain alkyl group having 1 to 10 carbon atoms, A represents either a single bond, a bond, or e; the cyclohexane ring has a trans configuration). A pyrimidine derivative characterized by the following characteristics, a liquid crystal composition containing the same, and a display using the same. The compound of the present invention is characterized by an extremely large positive dielectric constant anisotropy (hereinafter referred to as Δε). Therefore, by using a liquid crystal composition containing the compound (1) of the present invention, a liquid crystal display device with low driving voltage can be provided.

[Conventional technology]

Liquid crystal display devices utilize the electro-optic effect of liquid crystals, and liquid crystal phases used therein include nematic phase, cholesteric phase, and smectic phase. The most widely used display system at present is a twisted nematic (hereinafter referred to as TN) type that utilizes a nematic phase.

The liquid crystal display device is 1. Can be made small and thin.

2. Low driving voltage and low power consumption.

3. Since it is a light-receiving element, your eyes won't get tired even if you use it for a long time.

Because of these advantages, it has been applied to watches, calculators, audio equipment, various measuring instruments, automobile dashboards, etc. Particularly recently, it has been applied to displays with a large number of pixels, such as personal computer and word processor displays, as well as monochrome or color pocket televisions, and is attracting attention as a display device that can replace CRTs. As described above, liquid crystal display devices are being applied in many fields, and it is thought that the fields of application will further expand in the future. It is thought that the characteristics required of liquid crystal materials will change along with this, but the characteristics shown below are basic and indispensable.

1. Must be non-colored and thermally, optically, electrically and chemically stable.

2. Wide practical temperature range.

3. Fast electro-optical response speed.

4. Low driving voltage.

5. The rise of the voltage-light transmission regression characteristic is steep, and the temperature dependence of the threshold voltage (hereinafter referred to as Vlk) is small.

6. Wide viewing angle range.

[Problem to be solved by the invention]

Among these characteristics, many liquid crystals that satisfy characteristic 1 are known, but liquid crystal compounds that satisfy characteristic 2 or less as a single component are not known. Therefore, in order to obtain these characteristics, a liquid crystal composition in which several types of nematic liquid crystal compounds or non-liquid crystal compounds are mixed is used. 4 of these
In order to satisfy the characteristics of V lh and elastic constant (hereinafter referred to as
There is the following relationship between and Δε, and in order to lower Vlh, a liquid crystal compound with a large VlhLx(K/Δε)1/2 Δε and a small K is required.

Therefore, the present invention has been made to meet the demands under these circumstances, and its purpose is to create a liquid crystal composition with a low threshold voltage by mixing it with one or more other nematic liquid crystal compounds or non-liquid crystal compounds. An object of the present invention is to provide a novel liquid crystal compound that can be obtained.

[Means to solve the problem]

The present invention is based on the general formula (in the above formula, R represents a straight chain alkyl group having 1 to 10 carbon atoms, A represents any one of a single bond, a tassel bond, and e. Also, the cyclohexane ring has a trans configuration). A pyrimidine derivative characterized by the following characteristics, a liquid crystal composition containing the same, and a display using the same. Compound (1) of the present invention can be obtained by the following production method.

Step 1) React compound (2) with bromine in chloroform to obtain compound (3) Step 2) React compound (3) with cupric cyanide in N-methylpyrrolidone to obtain compound (4) obtain.

Step 3) Compound (4) is reacted with sodium nitrite and sulfuric acid in acetic acid to form a diazonium salt, and then reacted with cuprous chloride in hydrochloric acid to obtain compound (5).

Step 4) Compound (5) is reacted with dry hydrogen chloride gas in a mixed solvent of ethanol and benzene. Distill the solvent,
The obtained crystals are reacted with ammonia gas to form compound (6)
get.

Step 5) Compound (1) is obtained by reacting compound (6) and compound (7) or (8) with metallic sodium in ethanol.

When mixing the pyrimidine derivative of the present invention, the components of the base liquid crystal composition include, but are not limited to, the following compounds, which are compatible with all conventional liquid crystal compounds or their similar compounds. The resulting liquid crystal composition has a low threshold voltage.

R% c o o ()R' May represent a cy group, an alkoxymethylene group, CN or F, and the cyclohexane ring is in the trans configuration. ) The proportion of the compound of the present invention that can be mixed into this liquid crystal composition is 1 to 50% by weight, but a range of 3 to 30% by weight is particularly preferable in consideration of crystal precipitation in a low temperature region.

A liquid crystal display device using a liquid crystal composition containing at least one type of compound of the present invention is suitable for a liquid crystal display element using a time division drive method, and is particularly suitable for high time division drive in TN type and STN type liquid crystal display elements. is possible.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 (Synthesis of compound 1-a) Production process of 2-(3',5'-difluoro-4'-chlorophenyl)-5-butylpyrimidine 1) 2,6-difluoroaniline 10 into 180 mN of chloroform
0 g was dissolved, and 140 g of bromine was added dropwise into the solution. After stirring at room temperature for 3 hours, the reaction solution was poured into 10% potassium hydroxide solution. It was extracted with chloroform and the organic layer was extracted with 10
% potassium hydroxide solution and water. After chloroform was distilled off, vacuum distillation was performed (bpHo~115℃/3
mm Hg) Recrystallized from hexane to obtain 95 g of 4-bromo-2,6-difluoroaniline.

Step 2) 4-bromo-2,6-difluoroaniline 95
g, cupric cyanide 50gXN-methylpyrrolidone 32
0 mJ7 was placed in a flask and refluxed for 3 hours. after that,
The reaction solution was poured into a solution of 190 g of ferric chloride, 61 ml of a-hydrochloric acid, and 230 mg of water.

The solution was extracted with chloroform, washed with water and 10% potassium hydroxide solution, and then the chloroform was distilled off. The residue was distilled under reduced pressure and recrystallized from a mixed solvent of 4-cyano-2,6-difluoroaniline 13.
2g was obtained.

Step 3) 8.5 g of sodium nitrite was added to 64 ml of concentrated sulfuric acid, and after cooling to below 10° C., 75 ml of acetic acid, Q, was added.

After that, the solution was kept at 20-25℃ so that 4-cyano-2
, 19.2 g of 6-difluoroaniline were gradually added.

After stirring at 20-25° C. for 1 hour, 27 g of cuprous chloride was dissolved in 250 mN of concentrated hydrochloric acid, and the reaction solution was added dropwise thereto. After the dropwise addition was completed, the mixture was stirred at room temperature for 15 hours. After adding water to the reaction solution, it was extracted with chloroform and washed with water. Chloroform in the organic layer was distilled off, and the residue was recrystallized from a mixed solvent of methanol and acetone to give 2-chloro-5-cyano-1,
7.3 g of 3-difluorobenzene was obtained.

Step 4) Dissolve 7.3 g of 2-chloro-5-cyano-1,3-difluorobenzene in a mixed solvent of 25 ml of ethanol and 280 ml of 11% bene, cool to below 0°C, and add 1 ml of dry hydrogen chloride gas. It absorbed time.

Thereafter, the solvent of the reaction solution was distilled off, and the obtained crystals were added to 27 ml of ethanol, stirred, and cooled to below 0°C. After adding 38 mN of 16% ammonia-absorbed ethanol to the mixture, the mixture was stirred for 1 hour. The solvent of the reaction solution was distilled off to obtain 9.2 g of 4-chloro-3,5-difluorobenzamidine salt.

Step 5) Metallic sodium 4 into methanol 350mj7
．． Dissolve 4 g to prepare a sodium methylate solution. Therein were added 5.4 g of 4-chloro-3,5-difluorobenzamidine salt, 3-ethoxy-2-butyl acrolein (synthesis method: Chem.

Ber, 104.665-667 (1971))
Add 7g. Thereafter, the mixture was stirred at room temperature overnight and then refluxed for 1 hour. After ethanol was distilled off from the reaction solution, chloroform was added and washed with water, and chloroform was distilled off. After the residue was purified by chloroform-silica gel column chromatography, it was recrystallized from methanol to give 2-(3'
, 5'-difluoro-4'-chlorophenyl)-5-
0.8 g of butylpyrimidine was obtained. Crystals of this compound
Isotropic liquid transition point (hereinafter referred to as C-I point) is 64.8℃
Met.

Example 2 (Synthesis of compound 1-b) 2-(3',5'-difluoro-4'-chlorophenyl)-5-(4'-butylphenyl)pyrimidine manufacturing steps 1-4) Same as Example 1 4-chloro-3,5
-Difluorobenzamidine salt was obtained.

Step 5) 4-chloro-3,5-difluorobenzamidine salt 2g 11-dimethylamino-3-dimethylimmonio 2-(4-butylphenyl)-propene-(1)-
Perchlorate (synthesis method is 2°Chem, 17.293
~294 (1977)) 3.8g with methanol 3
3m, dissolved in IJ. Metal sodium 0 in this
．． A sodium methylate solution made from 5 g and 17 ml of methanol was added dropwise. After stirring overnight at room temperature, 2
Refluxed for an hour. After cooling the reaction solution, the precipitated crystals were filtered. The obtained crystals were purified by chloroform-silica gel column chromatography and then recrystallized from a mixed solvent of acetone and methanol to give 2-(3', 5'
-difluoro-4'-chlorophenyl)-5-(4'
0.9 g of -butylphenyl)pyrimidine was obtained. The crystal-smectic liquid crystal transition point (hereinafter referred to as C-3m point) of this compound is 105.4°C.
The isotropic liquid transition point (hereinafter referred to as Sm-I point) is 149℃
Met.

Example 3 (Synthesis of Compound 1-c) Preparation of 2-(3',5'-difluoro-4'-chlorophenyl)-5-[4'-()lans-4″'-butylcyclohexyl)phenylcopyrimidine Steps 1 to 4) 4-chloro-3,5 in the same manner as in Example 1
-Difluorobenzamidine salt was obtained.

Engineering fM5) 4-chloro-3,5-difluorobenzamidine salt 2g11-dimethylamino-3-dimethylimmonio 2-[4'-(trans-4'-butylcyclohexyl)phenyl]-propene-(1)- 4.6 g of perchlorate, 4-5 g of methanol and 17 rJ of methanol
A sodium methylate solution made from was added dropwise. Thereafter, the mixture was stirred at room temperature overnight and then refluxed for 2 hours. After cooling the reaction solution, the precipitated crystals were filtered. The obtained crystals were purified by chloroform-silica gel chromatography and then recrystallized from a mixed solvent of chloroform and acetone.
1.2 g of -(3',5'-difluoro-4'-chlorophenyl)-5-[4'-()lance-4-1butylcyclohexyl)phenyl]pyrimidine was obtained. The crystal-nematic liquid crystal transition point (hereinafter C-
(referred to as point N) is 133.

1℃, nematic liquid crystal-isotropic liquid transition point (hereinafter N-1
point) was 285.4°C. Example 4 (Liquid crystal composition) Commercially available mixed liquid crystal ZLI-1565 (manufactured by Merck & Co., Ltd., N-
I point 89.3℃) is used as the base liquid crystal, and currently - N - for boat fishing.
4-(trans-
41-pentylcyclohexyl) = 42-cyanobiphenyl and the compound of the present invention, 2-(3', 5
'-difluoro-4'-chlorophenyl)-5- [
A liquid crystal composition of 4'-(1-lance-4'''-butylcyclohexyl)phenyl]pyrimidine was prepared.

[Composition A]

ZLI-1565 90 parts by weight Cs
H++(HΣ(Carry!XCN 101iJi part)
Composition B] Compositions A and B consisting of 90 parts by weight of ZLI-1565 were prepared, and the refractive index anisotropy (hereinafter referred to as Δn) at the N-1 point was measured. The results are shown in Table 1.

Example 9 (Liquid crystal display element) As shown in FIG. 1, an electrode 3 made of a transparent conductive film (for example, an ITO film) is formed on glass substrates 1 and 2, and an alignment agent made of polyimide or the like is applied thereon. do. Next, the alignment control layer 4 was formed by rubbing, and the glass substrates 1 and 2 were placed facing each other with a sealant 6 in between, and the liquid crystal compositions A and B prepared in Example 8 were injected between the glass substrates, respectively. , by pasting polarizing plates on the outer surfaces of substrates 1 and 2,
Type liquid crystal display cells A and B were produced. Note that the cell gap was 8 μm.

The viewing angle dependence (α), steepness (β), and threshold voltage (Vlh) of the voltage-light transmission characteristics of the liquid crystal display cell thus produced were measured at 20° C. using AC static driving. In addition, α, β, V + h 5V31. is defined by the following formula.

The above measurement results are shown in Table 2.

Although the second display cell was used, similar effects were obtained when an STN type liquid crystal display cell was used.

〔Effect of the invention〕

As described above, when the compound of the present invention is mixed into a general liquid crystal composition, it has the effect of significantly lowering the threshold voltage without deteriorating the electro-optical properties (α value, β value). In these respects, the present invention is extremely useful as a basic component of liquid crystal compositions for super twisted nematic displays, which are currently the mainstream of liquid crystal display devices.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a liquid crystal display cell manufactured in an example of the present invention. 1.2...Glass substrate 3...Transparent electrode 4...Orientation control layer 5...Polarizing plate 6...Sealing agent or more

Claims (1)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the above formula, R represents a straight-chain alkyl group having 1 to 10 carbon atoms, A represents a single bond, ▲There are mathematical formulas, chemical formulas, tables, etc.▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼ Represents any of the following. Furthermore, a pyrimidine derivative characterized in that the cyclohexane ring is in a trans configuration. (2) A claim characterized by being represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1-a) (In the above formula, R represents a straight-chain alkyl group having 1 to 10 carbon atoms) Item 1. Pyrimidine derivative according to item 1. (3) A claim characterized by being represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (1-b) (In the above formula, R represents a straight-chain alkyl group having 1 to 10 carbon atoms) Item 1. Pyrimidine derivative according to item 1. (4) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1-c) (In the above formula, R represents a straight-chain alkyl group having 1 to 10 carbon atoms, and the cyclohexane ring is in the trans configuration.) Pyrimidine derivative according to claim 1, characterized in that: (5) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the above formula, R represents a straight-chain alkyl group having 1 to 10 carbon atoms, A is a single bond, ▲ Numerical formula, chemical formula, table, etc.) There are ▼, etc.
▲There are mathematical formulas, chemical formulas, tables, etc.▼ Represents any of the following. Furthermore, a liquid crystal composition characterized in that the composition contains at least one pyrimidine derivative represented by the following formula (the cyclohexane ring has a trans configuration). (6) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the above formula, R represents a straight chain alkyl group having 1 to 10 carbon atoms, A is a single bond, ▲ Numerical formula, chemical formula, table, etc.) There are ▼, etc.
▲There are mathematical formulas, chemical formulas, tables, etc.▼ Represents any of the following. Further, a liquid crystal display element characterized in that a liquid crystal composition containing at least one kind of pyrimidine derivative represented by the following formula (a cyclohexane ring has a trans configuration) is used.