JP2906729B2 - Optically active aromatic ester compound, its production method and use - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel liquid crystal compound useful as a display material, and more particularly to a liquid crystal material having ferroelectricity.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used as various optical devices at present, and mainly TN [twisted.
A nematic (Twisted Nematic) type display system is adopted. This method has advantages such as low power consumption and light receiving property that does not emit light by itself, so that eyestrain is small. However, responsiveness is extremely poor and a memory effect cannot be obtained.

[0003] In recent years, image displays have tended to require particularly high-speed response. For this reason, response characteristics of liquid crystal compounds have been actively improved. There is still a large difference in response time as compared to type display methods such as light emitting diodes, electroluminescence or plasma displays.
For this reason, efforts are being made to find new display systems that can take advantage of the advantages of liquid crystal displays that are light-receiving and have low power consumption, and that can respond at high speed.
Physical Letter (Appl. Plys. Lette.,) 36, 899 (1
980), a display device utilizing the optical switching phenomenon of ferroelectric liquid crystal has been proposed. This ferroelectric liquid crystal was discovered by RB Meyer et al. [Zunald Physique, 36 , L-69 (1975)] and has a chiral smectic C (hereinafter Sc ^* ) in terms of molecular arrangement ^. Phase, etc.).

[0004] Liquid crystal compounds exhibiting the Sc ^* phase have been studied so far, and many compounds have been synthesized. However, in order to use these compounds alone as a ferroelectric liquid crystal display device, the following conditions, ie, the following conditions:
(1) exhibits ferroelectricity over a wide temperature range including room temperature,
(2) It has an appropriate tilt angle, (3) has a large spontaneous polarization, and (4) has low viscosity. (5) As a result, it is necessary to exhibit a high-speed response. However, there is no known material which satisfies these requirements, and it is mainly used as a Sc ^* liquid crystal composition.

[0005] Sc^*Two methods for obtaining a liquid crystal composition
And one is Sc^*Mix multiple types of compounds that exhibit phase
Other methods are chiral or non-chiral
Smectic C (hereinafter S^(*)liquid crystal exhibiting phase c)
By adding a chiral compound to the compound or composition
is there. In the former method, strong spontaneous polarization or wide temperature range
Sc^*Liquid crystal composition having a phase (hereinafter referred to as Sc^*Liquid crystal composition
That. ) Can be easily obtained. In the latter way
Depends on the chiral compound to be added and its amount,
The mother S^(*)The liquid crystal compound or composition exhibiting the c phase is
If it is not chiral, there is no spontaneous polarization, so Sc
^*As a liquid crystal composition, it is difficult to obtain large spontaneous polarization. I
S^(*)Compound c has low viscosity
Sc^*High-speed response as a liquid crystal composition
It is possible to get excellent ones. S^(*)c mother liquid crystal
The chiral compound to be added to the composition is not necessarily a single compound.
Sc ^*It doesn't have to show a phase, it just needs to show a liquid crystal phase
is not.

[0006]

For the above reasons, a large spontaneous polarization can be obtained, or a sufficient spontaneous polarization can be induced by using as little as possible, thereby improving the orientation and maintaining the Sc ^* phase as much as possible. There is a desire for a chiral compound.

[0007]

Means for Solving the Problems The present inventors have assiduously studied to solve the above-mentioned problems, and have reached the present invention. That is, the present invention provides a compound represented by the general formula 1 (Wherein, X represents a -COO- or -OCO-, R ₁
And R ₂ have 1 carbon atom which may have a halogen atom.
Represents an alkyl group having from 20 to 20 or an alkoxyalkyl group having from 2 to 20 carbon atoms, m and k represent 1 or 2, and p and q represent 0 or 1. * Represents an asymmetric carbon atom. The present invention provides an optically active aromatic ester compound represented by the formula (1), its production method and use. In order to obtain a compound having a large spontaneous polarization in the compound represented by the general formula 1, p and / or q are preferably 1. For m and k, m = k =
In the case of 1, the compound (Chemical Formula 1) becomes a two-ring type, which causes a decrease in liquid crystallinity. When m = k = 2, the compound becomes a four-ring type, which causes an increase in viscosity. The three-ring type of 3 is more preferred.

Hereinafter, the present invention will be described in detail.

The optically active aromatic ester compound represented by the general formula 1 of the present invention is represented by the general formula 2 (Wherein, R ₂ , k, q and * have the same meanings as described above) and a compound represented by the general formula (Wherein, R ₁ , m, p and * have the same meanings as described above, and Y represents a hydroxyl group or a halogen atom), or
General formula 4 (Wherein, R ₂ , k, q, Y and * have the same meanings as described above) and a compound represented by the general formula (Wherein, R ₁ , m, p and * have the same meanings as described above).

In these reactions, the optically active phenol compound represented by the general formula (2) or (5) containing an asymmetric carbon as a raw material is, for example, 4-hydroxyacetophenone or 4-acetyl-4'-hydroxybiphenyl. After converting the hydroxyl group to benzyl ether using sodium hydride and benzyl bromide, reducing the acetyl group using sodium borohydride or the like to lead to α-hydroxyethyl, then acetyl chloride to acetic ester with pyridine, This acetate ester is asymmetrically hydrolyzed using an enzyme “lipase” to obtain an optically active α-hydroxyethyl group, and then is acylated or alkylated.
Finally, it can be produced by hydrogenation and debenzylation in the presence of a palladium catalyst.

The optically active carboxylic acid represented by the general formula (3) or (4) containing an asymmetric carbon can be obtained, for example, by converting methyl acetylbenzoate or methyl 4-acetyl-4'-biphenylcarboxylate to sodium borohydride. To reduce the acetyl group to an α-hydroxyethyl group, and then form an acetic ester with acetyl chloride-pyridine. Then, the acetic ester is asymmetrically hydrolyzed using an enzyme “lipase” to give an optically active α-hydroxyethyl group. Base. Then, when p or q is 0, it can be produced by alkylating with a halide or tosylate and sodium hydride, and further hydrolyzing the obtained ether form with an alkali. In the case of the above, the compound can be produced by hydrolyzing the ester group of the compound having an optically active α-hydroxyethyl group, and then acylating the α-hydroxyethyl group.

Such optically active phenol compounds (Chemical Formulas 2 and 5) and optically active carboxylic acid compounds (Chemical Formula 3)
And p- (1-alkyloxyethyl) phenol, 4 ′-(1-alkyloxyethyl)
-4-hydroxybiphenyl, p- (1-alkoxyalkyloxyethyl) phenol, 4 '-(1-alkoxyalkyloxyethyl) -4-hydroxybiphenyl, p- (1-alkyloxyethyl) benzoic acid, p-
(1-alkoxyalkyloxyethyl) benzoic acid,
4 '-(1-alkyloxyethyl) -4-biphenylcarboxylic acid, 4'-(1-alkoxyalkyloxyethyl) -4-biphenylcarboxylic acid, p- (1-alkylcarbonyloxyethyl) phenol, 4'- (1-
Alkylcarbonyloxyethyl) -4-hydroxybiphenyl, p- (1-alkoxyalkylcarbonyloxyethyl) phenol, 4 ′-(1-alkoxyalkylcarbonyloxyethyl) -4-hydroxybiphenyl, p- (1-alkylcarbonyloxy Ethyl) benzoic acid, p- (1-alkoxyalkylcarbonyloxyethyl) benzoic acid, 4 ′-(1-alkylcarbonyloxyethyl) -4-biphenylcarboxylic acid, 4′-
(1-alkoxyalkylcarbonyloxyethyl)-
Examples are 4-biphenylcarboxylic acids, which are acid halides (eg acid chloride, acid bromide),
Alternatively, phenols can be used as metal phenolates and phenol tosylate.

Here, the above-mentioned alkyl or alkoxyalkyl corresponds to R ₁ and R ₂ in the above-mentioned general formulas (2), (5) and (3) and (4). Methyl, ethyl,
Propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,
Alkyl such as heptadecyl, octadecyl, nonadecyl, eicosyl, methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl,
Methoxyhexyl, methoxyheptyl, methoxyoctyl, methoxynonyl, methoxydecyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, ethoxybutyl, ethoxypentyl, ethoxyhexyl, ethoxyheptyl, ethoxyoctyl, ethoxynonyl, ethoxydecyl, propoxymethyl, propoxyethyl , Propoxypropyl, propoxybutyl, propoxypentyl, propoxyhexyl, propoxyoctyl, propoxydecyl, butoxymethyl, butoxyethyl, butoxypropyl, butoxybutyl, butoxypentyl, butoxyhexyl, butoxyheptyl, butoxynonyl, pentyloxymethyl, pentyloxyethyl , Pentyloxypropyl, pentyloxybutyl, pentyloxypentyl, pentyl Kishiokuchiru, pentyloxy decyl, hexyl oxymethyl, hexyl oxyethyl, hexyl oxypropyl, hexyloxy butyl,
Hexyloxypentyl, hexyloxyhexyl, hexyloxyoctyl, hexyloxynonyl, hexyloxydecyl, heptyloxymethyl, heptyloxyethyl, heptyloxypropyl, heptyloxypentyl, octyloxymethyl, octyloxyethyl, decyloxymethyl, decyloxy Examples include alkoxyalkyl such as ethyl, decyloxypropyl, and the like.

The reaction between the optically active phenolic compound 2 and the optically active carboxylic acid compound 3 or the optically active carboxylic acid compound 4 and the optically active phenolic compound
The reaction with Chemical formula 5 can be carried out by applying a usual esterification method and reacting with a catalyst in the presence or absence of a solvent. When a solvent is used in this reaction, examples of the solvent include tetrahydrofuran, ethyl ether, acetone, methyl ethyl ketone, toluene, benzene, chlorobenzene,
Solvents which are inert to the reaction of aliphatic or aromatic hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, dimethylformamide, hexane and the like, ethers, halogenated hydrocarbons and the like, alone or in a mixture. The amount can be used without any particular limitation.

Examples of the catalyst include dimethylaminopyridine, triethylamine, tri-n-butylamine,
Organic or inorganic basic substances such as pyridine, picoline, lysine, imidazole, sodium carbonate, sodium methylate, potassium hydrogen carbonate and the like can be mentioned. Further, an organic acid or an inorganic acid such as toluenesulfonic acid, methanesulfonic acid, or sulfuric acid can be used as a catalyst. Further, esterifying agents such as dicyclohexylcarbodiimide, imidazoyl imidazole and the like can be used.

The amount of the catalyst used depends on the type of each reaction raw material used, the combination of the catalyst used, and the like, and cannot always be specified. For example, when an acid halide is used, one equivalent or more of the acid halide is used. Are used.

The reaction time is not particularly limited. After completion of the reaction, the desired optically active aromatic ester compound represented by the general formula 1 can be isolated from the reaction mixture by a usual separation means, for example, extraction, liquid separation, concentration, and the like.
If necessary, it can be purified by column chromatography, recrystallization, or the like.

[0018]

The compound of the present invention can induce a sufficient spontaneous polarization and improve the alignment property when mixed into a Sc ^* liquid crystal composition.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited by these examples.

Example 1 2.1 g (10 mmol) of (R)-(+)-4- (1-propoxyethyl) benzoic acid and (S)-(-)-4- (1
-Octyloxyethyl) phenol (2.5 g, 10 mmol) was dissolved in anhydrous dichloromethane (30 ml).
2.5 g (12 mmol) of dicyclohexylcarbodiimide and 0.2 g of 4-pyrrolidinopyridine were added, and the mixture was added at room temperature.
Stirred for hours. The resulting white precipitate was filtered off, the filtrate was diluted with 100 ml of toluene, and the toluene solution was washed with 5% acetic acid, water, 5% aqueous sodium hydrogen carbonate and brine in that order, and dried over anhydrous magnesium sulfate. The obtained toluene solution is concentrated under reduced pressure, and then purified by silica gel column chromatography (eluent: toluene-ethyl acetate) to obtain (+)-4- (1-octyloxyethyl) phenyl-4 ′-( 1-propoxyethyl) benzoate
3.7 g (81% yield) was obtained as a colorless viscous liquid. [Α] _D ²⁵ = + 24.8 ° (c = 0.83, CHCl ₃ )

Example 2 1.8 g (10 mmol) of (R)-(+)-4- (1-propoxyethyl) phenol was dissolved in 20 ml of pyridine, and (R)-(+)-4- (1) was dissolved at room temperature. -Hexyloxyethyl) benzoic acid chloride (2.7 g, 10 mmol) was added and reacted for 2 hours. The reaction mixture was 2N hydrochloric acid 10
Pour into 0 ml and extract with 200 ml of toluene, then
The toluene solution was washed with 1N aqueous hydrochloric acid, water, 5% aqueous sodium hydrogen carbonate and water in that order, and then dried over anhydrous magnesium sulfate. The obtained toluene solution was concentrated under reduced pressure, and then purified by silica gel column chromatography (eluent: toluene-ethyl acetate) to obtain (+)-4- (1-propoxyethyl) phenyl-4 '-(1-hexyl). Oxyethyl) benzoate
3.8 g (92% yield) was obtained as a colorless transparent liquid. [Α] _D ²⁵ = + 61.1 ° (c = 0.13, CHCl ₃ )

Examples 3 to 5 The reaction and post-treatment were carried out in the same manner as in Example 1 except that the optically active carboxylic acid compound and the optically active phenol compound were changed to the compounds shown in Table 1, and the results are shown in Table 1. The compound was obtained.

[0023]

Example 6 The compound obtained in Example 2 was prepared as a liquid crystal composition shown in Table 2. The preparation was carried out by mixing and weighing a predetermined compound at a predetermined weight while heating and melting it in a sample bottle. A polyimide-based polymer film is provided on a glass substrate on which an isodium oxide transparent electrode is provided, rubbed in a certain direction, and glass fibers (diameter: 5 μm) are used as spacers so that the rubbing directions of the two substrates are parallel. A liquid crystal cell was assembled, and the above liquid crystal composition was sealed in a vacuum to obtain a liquid crystal element. This liquid crystal element was combined with a polarizer, an electric field of 20 V was applied, and a change in transmitted light intensity was observed. As a result, it became clear that the switching element was used. At this time, the Sc ^* phase temperature range was 25 to 53 ° C, the spontaneous polarization was 1.8 nc / cm ² at 45 ° C, and a uniform domain was observed.

[0025]

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 69/773 C09K 19/20 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. The general formula 1 (Wherein, X represents a -COO- or -OCO-, R ₁
And R ₂ have 1 carbon atom which may have a halogen atom.
Represents an alkyl group having from 20 to 20 or an alkoxyalkyl group having from 2 to 20 carbon atoms, m and k represent 1 or 2, and p and q represent 0 or 1. * Represents an asymmetric carbon atom. ) An optically active aromatic ester compound represented by the formula: 2. The general formula 2 (Wherein, R ₂ , k, q and * have the same meanings as described above) and a phenol compound of the general formula (Wherein, R ₁ , m, p and * have the same meaning as described above, and Y represents a hydroxyl group or a halogen atom). A method for producing an optically active aromatic ester compound represented by the formula (1), wherein X is -COO-. 3. The general formula (Wherein, R ₂ , k, q, Y and * have the same meanings as described above) and a compound represented by the general formula (Wherein R ₁ , m, p and * have the same meanings as described above), characterized by reacting with an optically active phenol compound represented by the general formula ( ₁ ): A method for producing an ester compound (where X is -OCO-). 4. A liquid crystal composition comprising at least one optically active aromatic ester compound represented by the general formula (1). 5. A liquid crystal display device comprising a liquid crystal composition containing at least one optically active aromatic ester compound represented by the general formula 1.