JP2627646B2 - Optically active pyrimidine compound - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a specific optically active pyrimidine compound, and more specifically, a liquid crystal compound which is useful as an electro-optical element by utilizing a response of a ferroelectric smectic liquid crystal to an electric field. It is.
It relates to an optically active pyrimidine compound.

[Conventional technology and its problems]

Liquid crystals have been applied as various electro-optical elements and have been put to practical use in displays of watches, calculators and the like. Most of the liquid crystal display elements that are currently most practically used utilize a dielectric alignment effect of a twisted nematic liquid crystal or a cholesteric liquid crystal. However, when it is applied to a display element having a large number of pixels, which is expected, there are problems in terms of responsiveness, cost-last due to lack of a drive margin, and viewing angle characteristics. Therefore, research and development of a MOS panel and a TFT panel, which form a switching element for each pixel, are being actively conducted.

U.S. Pat. No. 4,367,924 discloses a liquid crystal device based on a new display principle using a smectic phase that eliminates such a defect of the liquid crystal device.

In addition, a liquid crystal compound exhibiting a smectic C ^* phase or an H phase composed of optically active molecules generally has an electric dipole density P and is known to be ferroelectric. Since these chiral smectic liquid crystals have electric dipole knowledge, they are more strongly affected by an electric field than by dielectric anisotropy.
Since the acting force has a property that the peak of P is directed in a direction parallel to the electric field, the direction of the molecule can be controlled by reversing the direction of the applied electric field. Then, by detecting the average change of the molecule in the major axis direction using two polarizing plates, it can be used as an electro-optical element.

The electro-optical element utilizing the response to the electric field of the smectic C ^* phase or the H phase has a spontaneous polarization and an acting force exerted by the electric field three to four orders of magnitude larger than those due to the dielectric anisotropy. It has a high-speed response superior to that of, and can have a memory function by performing appropriate orientation control, and is expected to be applied to high-speed optical shutters or displays with a large amount of display information. It is.

As for such a chiral smectic liquid crystal material having ferroelectricity, various compounds have been synthesized and their properties have been studied.

For example, Japanese Patent Application Laid-Open No. 61-215373 discloses an optically active alkoxyphenyl-alkylphenylpyrimidine compound, and the 13th Liquid Crystal Symposium Proceedings, pp. 46-47 (Showa 6).
In 2), an optically active alkoxyphenyl-alkyl or alkoxyphenyl-pyrimidine compound is proposed as a compound exhibiting a chiral smectic phase in a high temperature range over a wide temperature range.

However, in these compounds, since the optically active alkoxy group is derived from 2-methylbutanol, the alkyl group bonded to the asymmetric carbon atom is limited to an ethyl group. These compounds are not suitable for use as one component of a ferroelectric liquid crystal composition used near room temperature because the temperature at which a chiral smectic phase is exhibited is too high. In addition, these compounds have small spontaneous polarization and are not satisfactory in practical use.

[Means for solving the problem]

In view of the above situation, the present inventors have made intensive studies to find an optically active compound in which the liquid crystal composition for a display element can be used in a suitable temperature range. As a result, the liquid crystal composition is represented by the following general formula (I). It has been found that a novel optically active pyrimidine compound is a very suitable compound for the above purpose.

(Where R represents an alkyl group having 1 to 18 carbon atoms or an alkoxy group having 1 to 18 carbon atoms, R ′ represents a hydrogen atom or an alkyl group having 1 to 9 carbon atoms, X represents a hydrogen atom or Indicates a chlorine atom. However, R 'and X do not simultaneously become hydrogen atoms. m shows the number of 3-6. The optically active pyrimidine compound represented by the general formula (I) will be described in more detail.

Examples of the alkyl group having 1 to 18 carbon atoms represented by R include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, lauryl, myristyl, palmityl, stearyl and the like. Examples of the alkoxy group of Formulas 1 to 18 include an alkoxy group derived from the above alkyl group.

Examples of the alkyl group having 1 to 9 carbon atoms represented by R ′ include a methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl group and the like.

Since the compound of the present invention has an optically active group, it can be used as one component of a ferroelectric liquid crystal composition,
A compound in which R is an alkyl group having about 6 to 18 carbon atoms can be used as a liquid crystal having ferroelectricity.

Further, the compound of the present invention is a compound wherein the alkyl group bonded to the asymmetric carbon atom of the optically active alkoxy group has a chlorine atom or has an alkyl group having 3 to 12 carbon atoms, and is bonded to the asymmetric carbon atom. Compared with the corresponding pyrimidine compound having an optically active alkoxy group having an ethyl group as an alkyl group, the temperature at which a chiral smectic phase is exhibited is lower by about 10 to 20 ° C., and particularly when used near room temperature. It is suitable to be used as one component of the obtained ferroelectric liquid crystal composition.

Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited by the following examples.

Example 1 (S) -2- (4-n-decyloxyphenyl) -5
[4- (4'-methylheptyloxy) phenyl] pyrimidine Take 0.68 g of 55% sodium hydride and 5 ml of dimethylformamide, and add 4.05 g of 4- [2- (4-n-decyloxyphenyl) -5-pyrimidinyl] phenol under ice-cooling.
And a solution of 15 ml of dimethylformamide are added dropwise, followed by 10
The mixture was stirred at 0 ° C for 30 minutes. Then, 2.84 g of p-toluenesulfonic acid ester of (S) -4-methylheptanol was added thereto.
And 15 ml of dimethylformamide are added dropwise at 90 ° C.
Stirred for hours. After cooling, pour the reaction solution into a large amount of ice water,
The precipitated crystals were filtered, washed with water and dried. The obtained crude product was purified using silica gel column chromatography using n-hexane / methylene chloride (1/1) as a developing solvent, and further recrystallized from ethyl alcohol to obtain the desired (S) -2-
(4-n-decyloxyphenyl) -5- [4- (4 ′
-Methylheptyloxy) phenyl] pyrimidine was obtained.

As a result of an infrared spectroscopic analysis, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2925cm -1 (s), 2860cm -1} (m), 1605cm -1 (s), 1580cm -1 (m), 1520cm -1 (w), 1470cm -1 (vw), 1440cm -1 (s), 1395cm ^{-1 (vw), 1380cm -1 (} vw), 1335cm -1 (vw), 1285cm -1 (w), 1255cm -1 (s), 1190cm -1 (w), 1180cm -1 (w), 1130cm - ^{1 (vw), 1065cm -1 (} w), 1035cm -1 (w), 1000cm -1 (vw), 950cm -1 (vw), 930cm -1 (vw), 840cm -1 (m), 805cm -1 ^{(w), 730cm -1 (vw} ), 675cm -1 (vw), 660cm -1 (vw), 570cm -1 (vw), 500cm -1 (vw) scissors the compound in two glass plates of, As a result of phase morphology observation using a polarizing microscope, the following phase transition was confirmed.

This compound was poured into a 2 μm-thick glass transparent electrode cell that had been subjected to an alignment treatment by rubbing, and then heated to 200 ° C. to obtain an isotropic liquid. When the liquid crystal cell was gradually cooled to 160 ° C. and a rectangular wave of ± 15 V, 1 Hz was applied under crossed Nicols, a clear switching operation was confirmed. The response speed (time from application of the electric field to 90% rise) at that time was 280 μsec. The spontaneous polarization by the triangular wave method was 5.1 nC / cm ² .

On the other hand, the corresponding compound using 2-methylbutoxy group as the optically active alkoxy group described in the above-mentioned collection of the 13th meeting of the Liquid Crystal Symposium, the temperature at which the SmC ^* phase is exhibited is 109.0-158.5 ° C. Yes, the minimum temperature is about 10 ° C. higher than the compound of the present invention, and the temperature range is not only about 20 ° C., but the spontaneous polarization is much smaller at 0.2 nC / cm ² .

Example 2 Synthesis of (S) -2- [4- (6'-methylnonyloxy) phenyl] -5- (4-n-nonyloxyphenyl) pyrimidine 4- [5- (4-n-nonyloxyphenyl) -2-
Pyrimidinyl] phenol and 3.12 g of p-toluenesulfonic acid ester of (S) -6-methylnonanol were used in exactly the same manner as in Example 1, and the resulting crude product was treated with acetone. By recrystallization, the desired (S) -2- [4- (6'-methylnonyloxy) phenyl] -5- (4-n-nonyloxyphenyl) pyrimidine was obtained.

As a result of an infrared spectroscopic analysis, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2950cm ^-1 (s), 2880cm ^-1 (m), 1615cm ^-1 (s), 1585cm ^-1 (m), 1520cm ^-1 (w), 1470cm ^-1 (vw), 1440cm ^-1 (s), 1400cm ^{-1 (vw), 1380cm -1 (} vw), 1340cm -1 (vw), 1300cm -1 (w), 1260cm -1 (s), 1190cm -1 (w), 1180cm -1 (w), 1115cm - ¹ (vw), 1040 cm ^-1 (w), 1020 cm ^-1 (w), 840 cm ^-1 (m), 805 cm ^-1 (w), 730 cm ^-1 (vw), 680 cm ^-1 (vw), 660 cm ^-1 (Vw), 570 cm ^-1 (vw), 500 cm ^-1 (vw) The compound was sandwiched between two glass plates, and phase morphology was observed with a polarizing microscope. As a result, the following phase transition was confirmed.

Example 3 (S) -2- (4-n-octylphenyl) -5- [4
Synthesis of-(5'-methyloctyloxy) phenyl] pyrimidine The same operation as in Example 1 except that 3.60 g of 4- [2- (4-n-octylphenyl) -5-pyrimidinyl] phenol and 2.98 g of p-toluenesulfonic acid ester of (S) -5-methyloctanol were used. Was done. The obtained crude product was purified using silica gel column chromatography using n-hexane / ethyl ether (9/1) as a developing solvent,
Further recrystallization from ethyl alcohol / benzyl (8/2) gave (S) -2- (4-n-octylphenyl) -5-
[4- (5'-Methyloctyloxy) phenyl] pyrimidine was obtained.

As a result of an infrared spectroscopic analysis, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2950cm ^-1 (s), 2880cm ^-1 (m), 1615cm ^-1 (m), 1585cm ^-1 (w), 1535cm ^-1 (vw), 1520cm ^-1 (w), 1475cm ^-1 (vw), 1440cm ^{-1 (s), 1380cm -1 (} w), 1290cm -1 (m), 1255cm -1 (m), 1190cm -1 (m), 1120cm -1 (vw), 1050cm -1 (w), 1025cm - ^{1 (vw), 1000cm -1 (} vw), 950cm -1 (vw), 840cm -1 (m), 800cm -1 (w), 730cm -1 (vw), 660cm -1 (vw), 570cm -1 (Vw) This compound was sandwiched between two glass plates, and the phase morphology was observed with a polarizing microscope. As a result, the following phase transition was confirmed.

This compound was injected into a 2 μm-thick glass transparent electrode cell that had been subjected to an alignment treatment by rubbing, and then heated to 180 ° C. to obtain an isotropic liquid. When the liquid phase cell was gradually cooled to 120 ° C. and a rectangular wave of ± 15 V, 1 Hz was applied under crossed Nicols, a clear switching operation was confirmed. The response speed (time from application of the electric field to 90% rise) at that time was 310 μsec. The spontaneous polarization by the triangular wave method was 1.3 nC / cm ² .

On the other hand, the corresponding compound using a 6-methyloctoxy group as an optically active alkoxy group described in Example 2 of JP-A-61-215373 and in the proceedings of the 13th Liquid Crystal Symposium has a SmC ^* phase. The temperature range to be exhibited is 119 ~ 170 ℃ or 113 ~
At 173.8 ° C., the spontaneous polarization is 0.1 nC / cm ² or less, about 20 ° C. higher than the compound of the present invention, and the spontaneous polarization is much smaller.

Example 4 (S) -2- (4-n-octylphenyl) -5- [4
Synthesis of-(4'-methyloctyloxy) phenyl] pyrimidine Same as Example 3 except that 3.60 g of 4- [2- (4'-n-octylphenyl) -5-pyrimidinyl] phenol and 2.98 g of p-toluenesulfonic acid ester of (S) -4-methyloctanol were used. Operation and purification,
(S) -2- (4-n-octylphenyl) -5- [4
-(4'-Methyloctyloxy) phenyl] pyrimidine was obtained.

As a result of an infrared spectroscopic analysis, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2950cm ^-1 (s), 2880cm ^-1 (m), 1615cm ^-1 (m), 1585cm ^-1 (w), 1535cm ^-1 (vw), 1520cm ^-1 (w), 1470cm ^-1 (vw), 1440cm ^{-1 (s), 1395cm -1 (} vw), 1380cm -1 (w), 1290cm -1 (m), 1255cm -1 (m), 1195cm -1 (m), 1120cm -1 (vw), 1040cm - ^{1 (w), 1025cm -1 (} vw), 1000cm -1 (vw), 940cm -1 (vw), 840cm -1 (m), 800cm -1 (w), 730cm -1 (vw), 660cm -1 ^{(vw), 570cm -1 (vw} ), 490cm -1 (vw) scissors the compound in two glass plates of, as a result of the phase morphology observation with a polarizing microscope, it was confirmed following phase transition.

Example 5 (R) -2- (4-n-octylphenyl) -5- [4
Synthesis of-(6'-chloro-4'-methyloctyloxy) phenyl] pyrimidine 3.60 g of 4- [2- (4-n-octylphenyl) -5-pyrimidinyl] phenol and (R) -6-chloro-4
The same operation as in Example 1 was performed except that 3.33 g of p-toluenesulfonic acid ester of -methyloctanol was used. The obtained crude product was purified by silica gel column chromatography using n-hexane / ethyl ether (8/2) as a developing solvent, and further recrystallized from ethyl alcohol / benzene (8/2) to give (R) -2- (4-n-octylphenyl) -5- [4- (6'-chloro-4'-methyloctyloxy) phenyl] pyrimidine was obtained.

As a result of an infrared spectroscopic analysis, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2950cm ^-1 (s), 2860cm ^-1 (m), 1610cm ^-1 (m), 1580cm ^-1 (w), 1520cm ^-1 (w), 1460cm ^-1 (vw), 1435cm ^-1 (s), 1380cm ^{-1 (vw), 1285cm -1 (} w), 1250cm -1 (m), 1195cm -1 (w), 1130cm -1 (vw), 1035cm -1 (w), 940cm -1 (vw), 840cm - ¹ (m), 800 cm ^-1 (w), 730 cm ^-1 (vw), 660 cm ^-1 (vw), 565 cm ^-1 (vw) This compound is sandwiched between two glass plates, and the phase morphology is observed with a polarizing microscope. As a result, the following phase transition was confirmed.

This compound was injected into a 2 μm-thick glass transparent electrode cell that had been subjected to an alignment treatment by rubbing, and then heated to 180 ° C. to obtain an isotropic liquid. The liquid crystal cell was gradually cooled to 120 ° C., and a rectangular wave of ± 15 V, 1 Hz was applied under crossed Nicols, and a clear switching operation was confirmed. At that time, the response speed (time from application of the electric field to 90% rise) was 350 μsec. The spontaneous polarization by the triangular wave method was 44 nC / cm ² .

Example 6 (R) -2- (4-n-octylphenyl) -5- [4
Synthesis of-(6'-chloro-4'-methylhexyloxy) phenyl] pyrimidine 3.60 g of 4- [2- (4-n-octylphenyl) -5-pyrimidinyl] phenol and (R) -6-chloro-4-
P-Toluenesulfonic acid ester of methylhexanol
The same operation and purification as in Example 5 were carried out except for using 3.05 g, to obtain the desired (R) -2- (4-n-octylphenyl)
-5- [4- (6'-Chloro-4'-methylhexyloxy) phenyl] pyrimidine was obtained.

As a result of an infrared spectroscopic analysis, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2925cm ^-1 (s), 2860cm ^-1 (m), 1610cm ^-1 (m), 1580cm ^-1 (w), 1520cm ^-1 (w), 1460cm ^-1 (vw), 1440cm ^-1 (s), 1375cm ^{-1 (vw), 1285cm -1 (} w), 1250cm -1 (m), 1195cm -1 (w), 1130cm -1 (vw), 1030cm -1 (w), 940cm -1 (vw), 840cm - ¹ (m), 800 cm ^-1 (w), 730 cm ^-1 (vw), 660 cm ^-1 (vw), 565 cm ^-1 (vw) This compound is sandwiched between two glass plates, and the phase morphology is observed with a polarizing microscope. As a result, the following phase transition was confirmed.

This compound was injected into a 2 μm-thick glass transparent electrode cell that had been subjected to an alignment treatment by rubbing, and then heated to 180 ° C. to obtain an isotropic liquid. The liquid crystal cell was gradually cooled to 120 ° C., and a rectangular wave of ± 15 V, 1 Hz was applied under crossed Nicols, and a clear switching operation was confirmed. At that time, the response speed (time from application of the electric field to 90% rise) was 260 μsec. The spontaneous polarization by the triangular wave method was 8 nC / cm ² .

As is clear from the above results, the pyrimidine compound of the present invention has a low Sm3 / SmC ^* transition point, and is therefore advantageous for use as a component of a ferroelectric liquid crystal composition used near room temperature, and has spontaneous polarization. It has large features.

Claims (1)

(57) [Claims] 1. An optically active pyrimidine compound represented by the following general formula (I). (Where R represents an alkyl group having 1 to 18 carbon atoms or an alkoxy group having 1 to 18 carbon atoms, R ′ represents a hydrogen atom or an alkyl group having 1 to 9 carbon atoms, X represents a hydrogen atom or Indicates a chlorine atom. However, R 'and X do not simultaneously become hydrogen atoms. m shows the number of 3-6. )