JP2770385B2 - Pyrimidine derivatives - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel pyrimidine derivative used as an electro-optical display material.

[Summary of the Invention]

The present invention has the general formula (Wherein, R represents a straight-chain alkyl group having 1 to 10 carbon atoms) and has a nematic liquid crystal phase. Further, the liquid crystal compound of the present invention has the following characteristics.

1. High nematic isotropic liquid transition point (hereinafter referred to as NI point).

2. The dielectric anisotropy (hereinafter referred to as Δε) is positive and large.

Therefore, by using a liquid crystal composition in which the compound (1) of the present invention and another liquid crystal compound are mixed, a liquid crystal display device having a wide practical temperature range and a low driving voltage can be provided.

[Conventional technology]

The liquid crystal display device utilizes the electro-optic effect of the liquid crystal, and the liquid crystal phase used for this is a nematic phase,
There is a cholesteric phase and a smectic phase. The most widely used display method is a twisted nematic type (TN type) utilizing a nematic phase.

 Liquid crystal display devices are: 1. Small and thin.

2. Low driving voltage and low power consumption.

3.Since it is a light receiving element, eyes do not get tired even when used for a long time.

Because of its advantages, it has been applied to watches, calculators, audio equipment, various measuring instruments, and dashboards of automobiles. In particular, recently, it has been applied to a display of a very large number of pixels, such as a display of a personal computer or a word processor, and a black and white or color pocket television, and has attracted attention as a display device replacing the CRT. As described above, the liquid crystal display device is applied to various fields, and it is considered that the field of application will be further expanded in the future. It is expected that the characteristics required for the liquid crystal material will also change along with this, but the characteristics shown below are basic and indispensable.

1. No heat, light, electrical and chemical stability.

2. Wide operating temperature range.

3. Fast electro-optical response speed.

4. Low driving voltage.

5. The voltage-light transmittance characteristics must have a steep rise, and the threshold voltage should have little temperature dependence.

6. Wide viewing angle range.

[Problems to be solved by the invention]

Among these properties, many liquid crystals satisfying the property 1 are known, but no liquid crystal compound satisfying the property 2 or less with a single component is known. Therefore, in order to obtain these characteristics, a liquid crystal composition in which several kinds of nematic liquid crystal compounds or non-liquid crystal compounds are mixed is used. Generally, a combination of a liquid crystal compound having a relatively low molecular weight and a CN point (or melting point) near room temperature and a liquid crystal compound having a high molecular weight and an N-1 point of 200 ° C. or more is used. In order to satisfy the characteristics, the NI point is as high as possible and
A liquid crystal compound having the lowest possible -N point is indispensable. 4
In order to satisfy the characteristics of the above, the threshold voltage must be lowered. However, the following relationship exists between the threshold voltage Vth, the elastic constant K, and the anisotropy Δε of the dielectric constant. Δε is large to lower the voltage A liquid crystal material having a small K is required.

However, almost no liquid crystal compound satisfies the characteristics 2 and 4 at the same time, and at present, a composition combining a liquid crystal compound having two characteristics and a liquid crystal compound having the characteristics 3 is used.

Therefore, the present invention satisfies such a demand in the actual situation, and its object is to mix with one or more kinds of other nematic liquid crystal compounds or non-liquid crystal compounds to widen the practical temperature range and to increase the threshold voltage. To provide a novel liquid crystal compound capable of obtaining a liquid crystal composition having a low liquid crystal composition.

[Means for solving the problem]

General formula of the present invention (Wherein, R represents a straight-chain alkyl group having 1 to 10 carbon atoms).

Compound (1) of the present invention can be obtained by the following production method.

Step 1 Compound (2) is reacted with phosphorus oxychloride in dimethyl sulfoxide to obtain compound (3).

Step 2 Compound (4) is reacted with bromine in chloroform to obtain compound (5).

Step 3 Compound (5) is reacted with cuprous cyanide in N-methylpyrrolidone to obtain compound (6).

Step 4 Compound (6) is reacted with sodium nitrite and sulfuric acid in acetic acid to form a diazonium salt, and then reacted with cuprous bromide in hydrobromic acid to obtain compound (7).

Step 5 Compound (7) is reacted with dry hydrogen chloride gas in ethanol and benzene. The solvent is distilled off, and the obtained crystals are reacted with dry ammonia gas in ethanol to obtain a compound (8).

Step 6 Compound (3) and compound (8) are reacted with metallic sodium in ethanol to obtain compound (9).

Step 7 Compound (9) is reacted with cuprous cyanide in N-methylpyrrolidone to obtain compound (1).

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples and application examples.

Example 1 2- (2 ', 5'-difluoro-4'cyanophenyl)-
Preparation of 5- (4 ″ -butylphenyl) pyrimidine Step 1 54 ml of phosphorus oxychloride was added dropwise to 230 ml of dimethylformamide, followed by 42.1 g of 4-butylphenylacetyl chloride, followed by stirring at 70 ° C. for 3 hours. After cooling, dimethylformamide was distilled off, the residue was poured into ice water, excess phosphorus oxychloride was decomposed, and a solution prepared by dissolving 26 g of sodium perchlorate in water was added and cooled.

The precipitate was separated and recrystallized twice from ethanol to give 1-dimethylamino-3-dimethylimino-
58 g of 2- (4-butylphenyl) -propene- (1) -perchlorate were obtained.

Step 2 25 g of 2,5-difluoroaniline was dissolved in 45 ml of chloroform, and 35 g of bromine was added dropwise thereto. After refluxing for 1 hour, the mixture was poured into a 10% potassium hydroxide solution. It was extracted with chloroform and the organic layer was washed with 10% potassium hydroxide solution and water. After chloroform was distilled off, distillation under reduced pressure was carried out (bp 107-112 ° C / 5 mmHg). Recrystallization from a mixed solvent of hexane and chloroform gave 34 g of 4-bromo-2,5-difluoroaniline.

Step 3 4-bromo-2,5-difluoroaniline-34 g,
18 g of cuprous cyanide and 113 ml of N-methylpyrrolidone were placed in a flask and refluxed for 3 hours. Then ferric chloride 70
g, 23 ml of concentrated hydrochloric acid and 85 ml of water. The solution was extracted with chloroform, washed with water and a 10% potassium hydroxide solution, and then chloroform was distilled off. The residue was distilled under reduced pressure (bp 170-180 ° C./17 mmHg) and recrystallized from chloroform to obtain 6.1 g of 4-cyano-2,5-difluoroaniline.
I got

Step 4 Add 2.8 g of sodium nitrite to 20 ml of concentrated sulfuric acid,
After cooling to 10 ° C. or lower, 24 ml of acetic acid was added. Then the solution is 20 ~
6.1 g of 4-cyano-2,5-difluoroaniline was gradually added so as to keep the temperature at 25 ° C. 48% after stirring at 20-25 ° C for 1 hour
7 g of cuprous bromide was dissolved in 180 ml of a hydrobromic acid solution, and the reaction solution was dropped therein. After completion of the dropwise addition, the mixture was stirred at room temperature for 15 hours. After water was added to the reaction solution, the mixture was extracted with chloroform and washed with water. Chloroform of the organic layer was distilled off, and the residue was recrystallized from a mixed solution of methanol and acetone to obtain 5.8 g of 5-bromo-2-cyano-1.4-difluorobenzene.

Step 5 5.8 g of 5-bromo-2-cyano-1.4-difluorobenzene was dissolved in a mixed solution of 11.3 ml of ethanol and 40 ml of benzene, cooled to 0 ° C. or lower, and dried hydrogen chloride gas was added for 1 hour.
Allow time to absorb. Thereafter, the solvent of the reaction solution was distilled off, and the crystals of the residue were washed with ether. The obtained crystals are ethanol
The mixture was stirred into 8.3 ml, and cooled to 0 ° C. or lower. Into this one
After adding 6% ammonia-absorbing ethanol, the mixture was stirred for 1 hour. The solvent after the reaction was distilled off, and the residue crystals were washed with ether to obtain 3.4 g of 4-bromo-2.5-difluorobenzamidine hydrochloride.

Step 6 4-butyro-2.5-difluorobenzamidine hydrochloride 3.4 g, 1-dimethylamino-3-dimethylimmonio-2- (4-butylphenyl) -propene- (1)
5 g of perchlorate were dissolved in 46 ml of methanol. A sodium methylate solution prepared from 0.7 g of metallic sodium and 24 ml of methanol was dropped therein. After stirring at room temperature overnight, the mixture was refluxed for 1 hour. After cooling the reaction solution, water was added, and the precipitated crystals were collected. The resulting crystalline acetone,
Recrystallization was performed from a mixed solvent of methanol, and 2-
(2 ', 5'-difluoro-4'bromophenyl) -5-
2 g of (4 ″ -butylphenyl) pyrimidine were obtained.

Step 7 2 g of 2- (2 ', 5'-difluoro-4'bromophenyl) -5- (4 "-butylphenyl) pyrimidine,
0.8 g of cuprous cyanide and 6 ml of N-methylpyrrolidone were placed in a flask and refluxed for 2 hours. Then 2.7 g of ferric chloride,
The reaction solution was poured into a solution of 0.6 ml of concentrated hydrochloric acid and 2.7 ml of water. The solution was extracted with chloroform, washed with water and a 10% potassium hydroxide solution, and then chloroform was distilled off. The residue was recrystallized from a mixed solvent of acetone and methanol to give 2-
(2 ', 5'-difluoro-4'-cyanophenyl) 5-
0.5 g of (4 ″ -butylphenyl) pyrimidine was obtained. This compound has a nematic liquid crystal phase and has a CN point of 11
The temperature was 8 ° C and the NI point was 168.5 ° C.

〔The invention's effect〕

As described above, the compound of the present invention has a high NI point and a large Δε due to the attachment of a fluorine atom. Therefore, by mixing the compound of the present invention with a general liquid crystal composition, a liquid crystal composition having a wide practical temperature range and a low driving voltage can be obtained.

Claims (1)

(57) [Claims] (1) General formula (Wherein, R represents a linear alkyl group having 1 to 10 carbon atoms).