JPH0395164A - New ester compound and liquid crystal composition containing the same - Google Patents

Abstract

NEW MATERIAL:An ester compound expressed by the formula (R1 and R2 are 1-18C alkyl; C* is asymmetric carbon). EXAMPLE:4-[2-(4-Hexyloxyphenyl)-5-pyrimidinyl]phenyl, 2-pentyloxypropionate. USE:Useful as a liquid crystal material for optoelectronics-related elements, chemically stable and capable of providing a ferroelectric liquid crystal itself and imparting excellent properties by mixing thereof with other liquid crystal compounds. PREPARATION:For example, ethyl lactate is reacted with an alkyl halide in the presence of silver oxide. An alkali is then added to hydrolyze the resultant product to provide a 2-alkyloxypropionic acid, which is then subjected to dehydrating condensation reaction with a 2-alkylphenyl-5-hydroxyphenylpyrimidine to afford the exemplified compound in the formula.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention can provide a stable thermotroscopic liquid crystalline material, for example, for use in displays such as liquid crystal televisions, optical printer heads, optical Fourier transform elements, and lights. The present invention relates to a novel ester compound used in a liquid crystal material useful as a material for optical and electronic devices such as valves, and a liquid crystal composition containing this compound.

[Prior Art] Currently, liquid crystal materials are used as various display elements for watches, calculators, small televisions, etc., but these are mainly nematic liquid crystal materials. This nematic liquid crystal utilizes operation based on the weak interaction (ΔεE'/2) between the dielectric anisotropy Δε and the electric field E, so the response time to the electric field is several orders of magnitude.
It is slow at 0m SeC. For this reason, there are limits to its use in fields that require high-speed response, and the display capacity is also reaching its limit, which is one of the obstacles to increasing the screen size.

By the way, in 1975, R. 4-(4-n-decyloxybenzylideneamino)cinnamic acid-2-methylbutyl ester (DOBA
The emergence of ferroelectric liquid crystals, with MBC as a representative example, and the development of N, A. A surface-stabilized ferroelectric liquid crystal using bistable states in thin cells proposed by Clark et al.
The SSFLC) cell has made possible a liquid crystal cell with high-speed response on the μsec order and memory performance.

For this reason, many ferroelectric liquid crystal compounds have been synthesized to date.
Proposed. By the way, in order for these ferroelectric liquid crystal compounds to be used as liquid crystal materials, they must exhibit a chiral smectic C phase at least in a wide temperature range near room temperature, have large spontaneous polarization, and be chemically stable. is necessary. However, it is difficult to obtain a single compound that satisfies these requirements, and as with conventional nematic liquid crystal materials, there is a movement toward solving this problem by mixing several types of compounds. As this type of liquid crystal material, a type of phenylpyrimidine compound has been proposed (for example, Japanese Patent Application Laid-Open No. 63-235393).

However, there are still only a few types of these ferroelectric liquid crystal compounds, and a fully satisfactory ferroelectric liquid crystal composition has not yet been produced.

[Problem to be solved by the invention]

The present invention solves the above problems, and an object of the present invention is to be chemically stable, exhibit a chiral smectic C phase in a wide temperature range near room temperature, and be useful as a material for liquid crystal compositions having large spontaneous polarization. The purpose of this research is to propose new ester compounds.

[Means for Solving the Problems] The present invention is based on the following general formula CH, I R, , R, represents an alkyl group having 1 to 18 carbon atoms, C8 represents an asymmetric carbon, and a liquid crystal composition containing this compound.

R, , R, in the compound of the above formula of the present invention are selected from alkyl groups having 1 to 18 carbon atoms from a practical production standpoint.

Representative examples of this compound and their physical and chemical properties are as follows.

CH, C, H,, ○−◎１◎−◎−○C−C”H−0−C,H
,,0 I R (KBr, cm ""): 2920,
2850, +770. 1605, +580,14
30, 1255, 1120. 795H-N
M R (CDCI, medium, TMS standard, δ value ppm)
:8.95 (2H, d), 8.44 (2}1, d)
,7. 63 (2H, d), 7.27 (2H, d),
7.0 (2H, d), 4.3 (IH, q), 4.1 (2
H, t), 3.8-3.1 (2H), 2.0-1.1 (
14H), 0,9. (6H,t)M": 490 The compound represented by the above general formula can be synthesized by the following method.

Ethyl lactate and an alkyl halide are reacted in the presence of silver oxide to form a 2-alkyloxyprobionic acid ester, and then an alkali is added to perform hydrolysis to obtain a 2-alkyloxyprobionic acid. Next, this compound and 2-alkylphenyl-5-hydroxyphenyl birimicin are subjected to a dehydration condensation reaction to obtain 4-(2-(4-alkyloxyphenyl)-5 represented by the general formula above).
(pyrimidinyl) phenyl, 2-alkyloxyprobionic acid ester can be obtained.

This compound can be used alone as a ferroelectric liquid crystal material, but it can also be used in combination with other liquid crystal materials.

For example, when mixed with a pyrimidine-based base liquid crystal material,
Without changing the phase series of the base liquid crystal, it increases the transition temperature from the smectic A phase to the chiral smectic C phase, increases the response speed, and further increases the angle of rotation, achieving extremely good effects.

[Example] (-) Ethyl monolactate 8. 3g (70mmol), l
-25 g (126 mmol) of iodobentane and 13.6 g (58 mmol) of silver oxide were mixed and left at room temperature for one week. Next, after filtering the solid content and washing the furnace liquid with a 5% aqueous sodium hydroxide solution and water,
Dry with magnesium sulfate. Magnesium sulfate was removed by filtration, the furnace liquid was concentrated, and distilled under reduced pressure to obtain 117 韡12
1℃/3 1~3 4 mml {g fraction was collected and (
-)-2-pentyloxypropionic acid ethyl ester was obtained. The yield was 41%, the optical rotation α (Q = 1 cm, nea
t) was -5.32.

(2) - -2-Pentyloxypropionate (-)-2-pentyloxypropionic acid ethyl ester 5. 24g (27.8mmol), 26ml of ethanol, 26ml of water, 2.3ml of sodium hydroxide
0 g was added, and the mixture was heated under reflux for 2 hours. After distilling off the ethanol, 40 ml of 4N hydrochloric acid aqueous solution was added, followed by extraction with ether. This ether layer was washed with water and then dried over magnesium sulfate. After removing magnesium sulfate, it was distilled under reduced pressure to 127-128°C/4,0 mml.
-1 g of fraction was collected to obtain (-)-2-pentyloxyprobionic acid. The yield was 76%, the optical rotation a (Q
= 1 cm, neat) was -5.97.

Using 4-hexyloxycyanobenzene as a starting material, the Journal
further Praktische Chemie)
3 2 1.06 g of 2-hexyloxyphenyl-5-hydroxyphenylpyrimidine (3
．． 0 4 mmol), (-)-2-pentyloxyprobionic acid 0.4 8 g (3.0 mmol) and 1,4
-dimethylaminopyridine 4 6mg (0.38m
After adding 80 ml of methylene chloride to the mol) and stirring to make it homogeneous, N,N-dicyclohexylcarbodiimide 0
．． 88 g (4.27 mmol) was added. After stirring overnight, the white crystals were filtered, the filtrate was concentrated, and dried under reduced pressure.
White crystals were obtained. This crystal was purified by silica gel chromatography and recrystallized to give 4-(2-(4-hexyloxyphenyl)-5-
1.32 g (yield: 90%) of pyrimidinyl)phenyl, 2-bentyloxyprobionic acid ester was obtained.

(4) The above compound was injected into a 3 μm thick cell made of glass with transparent electrodes coated with polyimide and rubbed, and observed with a polarized light microscope while controlling the temperature on a hot stage. I did it. The temperature was changed at a rate of 2°C per minute.

As a result, during the cooling process, the phase changed from an isotropic liquid to a chiral smectic C phase at 146.4°C, and became a crystal at 100°C. In addition, during the temperature raising process, it became a chiral smectic C phase at 100.3°C and became an isotropic liquid at 146.4°C.

In addition, when spontaneous polarization was measured using trigonometry, it was found to be 14]. ，
4°C, 3ovpp, 100tz {z(7) Condition Te148
．． 4 nC/crd, 126, . 4°C, 40Vp
It showed 1 8 3 nC/cnl under the conditions of p, tootlz.

On the other hand, a base liquid crystal mixed with a non-chiral phenylpyrimidine compound that forms a nematic phase at 67 to 62°C, a smectic A phase at 62 to 47°C, and a smectic C phase at 47 to 7°C was combined with the above. 4-(2-(4-hexyloxyphenyl)-5-pyrimidinyl)phenyl,
When 15% of 2-pentyloxybrobionic acid ester was added and liquid crystallinity was evaluated in the same cell as above,
It takes a cholesteric phase at 76-73°C, a smectic A phase at 73-71°C, a chylanoresmectic C phase at 71-5°C, and has a spontaneous polarization of 16 nC/cn? at 25°C. ,
The tilt angle was 27'' and the response time was 38 μsec.

From this result, the compound of the present invention has a chiral smectic C phase over a wide temperature range and exhibits large spontaneous polarization, and furthermore, when the compound of the present invention is mixed into the base liquid material, it changes the phase series of the base liquid crystal. Smectic A
It can be seen that it has the effect of increasing the transition temperature from the chiral smectic C phase, increasing the response speed, and increasing the tilt angle.

[Effect of the invention] The novel compound of the present invention is chemically stable, becomes a ferroelectric liquid crystal by itself, and has exceptional properties such as imparting good properties when mixed with other liquid crystal compounds. It can be used as a useful liquid crystal material for optoelectronic devices.

Claims (2)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. A novel ester compound with characteristics. (2) A liquid crystal composition containing the compound according to claim (1).