JP3206682B2 - Phenylpyrimidine derivative having optically active cyanocyclopropane ring and liquid crystal composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel phenylpyrimidine derivative having an optically active cyanocyclopropane ring and a liquid crystal material containing the same, particularly to a ferroelectric liquid crystal display material having excellent responsiveness and memory properties.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used at present because of their excellent features (low-voltage driving, low power consumption, thin display, use in bright places, and no eyestrain). However, the TN type, which is the most common display method, has a very slow response as compared with other light-emitting display methods such as a CRT, and obtains display memory (memory effect) when the applied electric field is cut off. Therefore, there are many restrictions on application to moving images such as an optical shutter and a printer head that require a high-speed response, and a television that requires a time-division drive, and the display method is not always suitable.

Recently, a display method using a ferroelectric liquid crystal has been reported.
Since a high-speed response of 000 times and a memory effect can be obtained, it is expected as a next-generation liquid crystal display device, and research and development are being actively conducted at present.

The liquid crystal phase of the ferroelectric liquid crystal belongs to a tilt type chiral smectic phase. Among them, a chiral smectic C (hereinafter abbreviated as SC ^* ) phase has the lowest viscosity and is most desirable. Although many liquid crystal compounds exhibiting the SC ^* phase have already been synthesized and studied, the following conditions for use as a ferroelectric liquid crystal element, namely, (a) exhibiting the SC ^* phase in a wide temperature range including room temperature, (B) In order to obtain a good orientation, the SC ^* phase has an appropriate phase series on the high temperature side and its helical pitch is large; (c) it has an appropriate tilt angle; Small,
There is no known compound which satisfies (e) a certain degree of spontaneous polarization and (f) a fast response. Therefore, it is necessary to mix several or more compounds to use as a liquid crystal composition exhibiting an SC ^* phase (hereinafter abbreviated as SC ^* liquid crystal composition).

[0005] As a method for preparing an SC ^* liquid crystal composition, a smectic C (hereinafter, referred to as SC) comprises an achiral compound.
The method of adding a dopant composed of an optically active compound as a so-called chiral dopant to a base liquid crystal (hereinafter abbreviated as SC base liquid crystal) exhibiting a phase can provide a composition having a lower viscosity and a higher speed. Most common because it allows a response.

The compound used as a chiral dopant alone does not necessarily need to exhibit the SC ^* phase and does not need to exhibit even the liquid crystal phase, but it can induce sufficient spontaneous polarization in the liquid crystal composition with a small amount of addition. It is necessary to exhibit properties such as a sufficiently large spiral pitch induced as a dopant.

In order to induce large spontaneous polarization as a chiral dopant, it is necessary that a group having a strong dipole moment is fixed as close as possible to the central skeleton (core) and asymmetric carbon of the compound molecule. That is already known. Based on such an idea, the present inventors have made general formula (II)

[0008]

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(Wherein R ³ represents an alkyl group or an alkoxyl group, and ring B is a 1,4-phenylene group or a trans-1,4-cyclohexyl group which may be substituted by one or two fluorine atoms. An optically active cyanocyclopropane derivative represented by the formula (1) represents a silene group, and R ⁴ represents an alkyl group. It has been found that it is possible to prepare an SC ^* liquid crystal composition having properties. (36th liquid crystal discussion meeting preprints, 36 pages, and JP-A-3-236365)

[0010]

As described above, it has been known that an optically active cyanocyclopropane derivative has excellent properties as a chiral dopant, but in particular, it lowers viscosity and further improves response. Was required.

There are many known liquid crystal skeletons that tend to exhibit an SC (or SC ^* ) phase. Typical examples thereof include an ester type such as phenyl benzoate and a phenylpyrimidine type. Can be. Comparing the two, the phenylpyrimidine-type compound has the lower viscosity, and is therefore most often used as a constituent material of the SC parent liquid crystal.

Therefore, it is considered that the optically active compound for a chiral dopant is preferably a phenylpyrimidine type skeleton rather than an ester type skeleton in order to reduce the viscosity.

[0013] An object of the present invention is to provide a phenylpyrimidine derivative having an optically active lactone ring capable of achieving the above object, and further comprise a ferroelectric substance containing the same and capable of high-speed response. An object of the present invention is to provide a liquid crystal display material.

[0014]

According to the present invention, there is provided a compound represented by the general formula (I):

[0015]

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(In the formula, R ¹ represents a fluorine atom or an alkyl group having 1 to 18 carbon atoms which may be substituted by an alkoxyl group having 1 to 10 carbon atoms, preferably 4 to 12 carbon atoms. X represents a linear alkyl group.
Represents a single bond or -O-, and m represents 0 or 1, but preferably represents m = 0. Ring A represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group which may be substituted by one or two fluorine atoms, preferably a 1,4-phenylene group. R
² represents an alkyl group having 1 to 10 carbon atoms, preferably a linear alkyl group having 1 to 10 carbon atoms, and the asymmetric carbon atoms at the 1- and 2-positions of the cyclopropane ring are each independently And (R) or (S) arrangement. A phenylpyrimidine derivative having an optically active cyanocyclopropane ring represented by the formula:

The present invention also provides a liquid crystal composition containing the optically active compound represented by the general formula (I).

The liquid crystal composition of the present invention has the general formula (I)
And at least one compound of the above general formula (I) in a SC matrix liquid crystal, which is a main component, for use in ferroelectric liquid crystal display. SC ^* liquid crystal compositions containing part or all of the dopant are most desirable.

Further, by adding a small amount of the compound of the general formula (I) of the present invention to a nematic liquid crystal, it is possible to prevent a so-called reverse domain as a TN type liquid crystal, or to obtain a TN type liquid crystal.
It can also be used for applications as an N-type liquid crystal.

The compound of the general formula (I) of the present invention can be produced, for example, according to the following production method. General formula (III)

[0021]

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(Wherein Y represents a halogen atom, preferably a bromine atom, and the absolute configuration of R ² and the asymmetric carbon atom at the 1- and 2-positions of the cyclopropane ring is represented by the general formula (I) An optically active cyanocyclopropane derivative represented by the following general formula (IV):

[0023]

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Wherein R ¹ , X, m and ring A have the same meanings as in formula (I), and Z represents a halogen atom, but preferably represents a chlorine atom. Is reacted in the presence of a nickel complex or the like to obtain a compound of the general formula (I). Here, as the nickel complex, for example, dibromobis (triphenylphosphine) nickel (II) is preferable.

The general formula (II) used here as a raw material
The optically active cyanocyclopropane derivative (I) can be produced, for example, as follows. General formula (V)

[0026]

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(Wherein Y represents the same meaning as in the general formula (III)), a strong base is used as an anion of a phenylacetonitrile derivative, and this is represented by the general formula (V
I)

[0028]

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(Wherein R ² and * have the same meanings as in formula (I)) to react with an optically active oxirane derivative represented by formula (VII)

[0030]

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(Wherein Y represents the general formula (III), R ² and *
Represents the same meaning as in general formula (I), respectively.)
To obtain an optically active 4-hydroxyalkanenitrile derivative. This is reacted with p-toluenesulfonyl chloride to form a tosylate, and then reacted with a strong base to obtain a compound of the general formula (I).

Here, some of the optically active oxirane derivatives of the general formula (VI) are commercially available, and compounds that are not commercially available can be easily synthesized from commercially available optically active epichlorohydrin.

As described above, the general formula (I) of the present invention
Can be obtained. Specific specific compounds belonging to these include phase transition temperature such as melting point, infrared absorption spectrum (IR), nuclear magnetic resonance spectrum (NMR),
It can be confirmed by means such as mass spectrum (MS).

Representative examples of the compound of the general formula (I) thus obtained are shown in Table 1.

[0035]

[Table 1]

(In the table, Cr represents a crystal phase, I represents an isotropic liquid phase, the phase transition temperature represents a transition temperature between the left phase and the right phase of the numeral, and Cr42I represents the crystal phase. The transition temperature between the liquid phase and the isotropic liquid phase is 42 ° C. The same applies hereinafter.)

The compound of the formula (I) of the present invention can induce a sufficiently large spontaneous polarization by adding a small amount of the compound to the SC matrix liquid crystal, thereby obtaining a liquid crystal composition capable of high-speed response.

For example, only 5% by weight of the compound (No. 1) in Table 1 and a phenylpyrimidine-based base liquid crystal 95
The spontaneous polarization at 25 ° C. of the SC ^* liquid crystal composition composed of% by weight was +6.8 nC / cm ² , and a high-speed response of 50 μsec was confirmed in a display cell manufactured using the same. On the other hand, among the ester-type optically active compounds of the aforementioned general formula (II), the typical formula (R)

[0039]

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The spontaneous polarization at 25 ° C. of the SC ^* liquid crystal composition comprising 5% by weight of the compound and 95% by weight of the same base liquid crystal was +7.4 nC / cm ² , and the response measured in the same manner was 79 μs. It has become quite late.

The compound of the general formula (I) has the general formula (II)
In the above compound, the ester-type skeleton was replaced with a phenylpyrimidine-type skeleton, but it can be understood that the responsiveness was greatly improved by the replacement.

Further, the compound (No. 1) 10
% By weight and 90% by weight of the same base liquid crystal, an SC ^* liquid crystal composition was prepared and left at room temperature for a long time.
No precipitation or phase separation was observed. On the other hand, when an SC ^* liquid crystal composition comprising 10% by weight of the compound of the formula (R) and 90% by weight of the same base liquid crystal was prepared and allowed to stand at room temperature, phase separation was observed in part. Therefore, it is clear that the compound of the general formula (I) of the present invention is superior to the compound of the general formula (II) particularly in the compatibility with phenylpyrimidine-based parent liquid crystals.

As described above, the compound of the general formula (I) of the present invention can induce a sufficiently large spontaneous polarization even when added in a small amount. Therefore, the added amount to the SC parent liquid crystal should be about 2% or more in total. When used in combination with other chiral dopants, even smaller amounts are possible.

The compound of the general formula (I) of the present invention is
Some of them alone do not show the SC ^* phase, and when such a compound is added to the base liquid crystal, the composition may tend to lower the maximum temperature of the SC ^* phase. Usually, the addition amount required to induce sufficient spontaneous polarization is small, so there is no particular problem.
It is preferable to use a base liquid crystal having a high maximum temperature of the C phase.

In general, an optically active compound which induces a large spontaneous polarization even when added in a small amount has a tendency to narrow the temperature range of the chiral nematic (N ^* ) phase or to easily eliminate it. In many cases, the smectic A (SA) phase has a strong tendency to expand the temperature range. When such a compound is used as a chiral dopant, the phase sequence of the obtained SC ^* liquid crystal composition may be I (isotropic liquid phase) -SA (smectic A) -SC ^* from a high temperature range. Many.

However, according to the current alignment technology, it is most desirable that the SC ^* liquid crystal composition exhibits an IN ^* -SA-SC ^* phase sequence from a high temperature range. Since the compound of the general formula (I) of the present invention has almost no tendency to narrow the temperature range of the N ^* phase upon addition, it is very easy to obtain the above-mentioned desirable phase series.

In order to obtain excellent orientation, the above-mentioned I-
In addition to the N ^* -SA-SC ^* phase series, N ^* and SC ^* phases,
In particular, it is also important that the helical pitch in the N ^* phase is large. In order to increase the helical pitch, it is sufficient to add an optically active compound in which the direction of the induced helical is reversed. However, the compound of the general formula (I) of the present invention requires a small amount of addition. The helical pitch is large for the magnitude of the induced spontaneous polarization, and the adjustment is relatively easy.

The SC compound used in the base liquid crystal to which the compound of the general formula (I) of the present invention is added as a dopant includes, for example, the following general formula (A)

[0049]

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(Wherein, R ^a and R ^b represent a linear or branched alkyl group, alkoxyl group, alkoxycarbonyl group, alkanoyloxy group or alkoxycarbonyloxy group. Or a phenylbenzoate compound represented by the general formula (B):

[0051]

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(Wherein R ^a and R ^b have the same meanings as in formula (A)). The general formula (C) including the general formulas (A) and (B)

[0053]

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(Wherein R ^a and R ^b have the same meanings as in formula (A), and ring L and ring M are each 1,4
-Phenylene group, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6
- diyl group, 1,3-dioxane-2,5-diyl group, or represents these halogen substituents may be the being the same or different, Z ^a is -COO -, - O
_{CO -, - CH 2 O -} , - OCH 2 -, - CH 2 CH 2 -,
—C≡C— or a single bond. The compound represented by the formula (1) can be used for the same purpose.

In order to extend the temperature range of the SC phase to a high temperature range, the general formula (D)

[0056]

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(Wherein, R ^a and R ^b have the same meanings as in formula (A), and ring L, ring M and ring N have the same meanings as ring L and ring M in formula (C). represents, represented by may be the being the same or different, Z ^a and Z ^b are each the formula represents the same meaning as Z ^a of (C), may be the same or different) Tricyclic compounds can be used.

It is effective to mix these compounds and use them as an SC liquid crystal composition. However, it is only necessary to show the SC phase as the composition, and it is not necessary for each compound to show the SC phase. .

By adding the compound of the general formula (I) of the present invention and, if necessary, other optically active compounds to the SC liquid crystal composition thus obtained as a chiral dopant,
A liquid crystal composition exhibiting the SC ^* phase in a wide temperature range including room temperature can be easily obtained.

The compound of general formula (I) of the present invention is
The SC ^* liquid crystal composition obtained by adding to the base liquid crystal can be used as a display cell, for example, by enclosing it as a thin film of about 1 to 20 μm between two transparent glass electrodes. In order to obtain good contrast, it is necessary to use a monodomain that is uniformly oriented, and many methods have been tried. In order to show good alignment, the liquid crystal material needs to show a phase series of IN ^* -SA-SC ^* from a high temperature side and to increase the helical pitch in the N ^* phase and the SC ^* phase. However, when the compound of the general formula (I) of the present invention is used as described above, it is easy to obtain such a composition.

[0061]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but of course the gist and scope of the present invention are not limited by these examples.

The structure of the compound is represented by NMR, IR, MS
And elemental analysis. The phase transition temperature was measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DSC). (KBr) in IR
Indicates measurement by tablet molding, and (neat) indicates measurement by liquid film. CDCl _{3 in} NMR represents a solvent, s represents a singlet, d represents a doublet, t represents a triplet, m represents a multiplet, and for example, dt represents a double triplet. M in MS
⁺ Represents the parent peak, and the number in parentheses represents the relative intensity of that peak. All “%” in the composition represent “% by weight”.

Example 1 Synthesis of (1R, 2S) -1-cyano-2-hexyl-1- [4- (5-octylpyrimidin-2-yl) phenyl] cyclopropane (Compound No. 1)

[0064]

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(1-a) Synthesis of (4R) -2- (4-bromophenyl) -4-hydroxydecanenitrile 736 ml (5.3 mmol) of diisopropylamine,
In a solution of tetrahydrofuran (THF) 10 ml, -78
3.3 ml of 1.5 M butyllithium-hexane solution at ℃
(5.3 mmol) and stirred for 30 minutes. After completion of the reaction, 980 mg of 4-bromophenylacetonitrile
(3.0 mmol) of THF (5 ml) and hexamethylphosphoric triamide (1 ml) were added, and the mixture was stirred for 30 minutes. Next, 769 mg of (R) -1,2-epoxyoctane
(6.0 mmol) in 3 ml of THF was added and the temperature was raised to room temperature. After neutralization with 3M hydrochloric acid, the reaction product was extracted twice with 60 ml of ethyl acetate. After concentrating the organic layer,
Separation and purification using silica gel chromatography (hexane / ethyl acetate = 10/1) gave (4R) -2-
996 mg (61% yield) of (4-bromophenyl) -4-hydroxydecanenitrile was obtained.

Colorless liquid IR (neat) 3430, 2950, 2930, 2
860, 2240, 1485, 1405, 1070, 1
010,820 cm ^-1 Non-polar component ¹ H NMR (CDCl ₃ ) δ 0.89 (t, J =
6.7 Hz, 3H), 1.24 to 1.40 (m, 10
H), 1,76-1.83 (ddd, J = 13.9,1
0.8, and 4.3 Hz, 1H), 1.94 to 2.0
2 (m, 1H), 3.92 to 4.00 (m, 1H),
4, 17 (dd, J = 11.6 and 4.3 Hz, 1
H), 7.24 (d, J = 8.4 Hz, 2H), 7.5
1 (d.J = 8.4 Hz, 2H)

Polar component ¹ H NMR (CDCl ₃ ) δ 0.86 (t, J =
6.7 Hz, 3H), 1.19 to 1.38 (m, 8
H), 1.41 to 1.49 (m, 2H), 1.91 to
1.98 (m, 1H), 2.11 (ddd, J = 13.
9, 9.9, and 5.3 Hz, 1H), 3.33-
3.40 (m, 1H), 4.05 (dd, J = 10.0
and 5.3 Hz, 1H), 7.25 (d, J = 8.6)
Hz, 2H), 7.52 (d, J = 8.5 Hz, 2H) MS m / z 325 (M ^{++ 2,} 4), 323 (M ⁺ ,
4), 307 (15), 305 (15), 223 (1
1), 210 (15), 209 (78), 208 (1
4), 207 (78), 196 (39), 194 (3
7), 116 (54), 77 (22), 69 (38),
55 (100)

(1-b) (1R, 2S) -1- (4-
Synthesis of (bromophenyl) -1-cyano-2-hexylcyclopropane (4R) -2- (4-bromophenyl) -4-hydroxydecanenitrile 996 mg obtained in (1-a) above
To a solution of (3.1 mmol) and 20 mg of 4-N, N dimethylaminopyridine in 3 ml of pyridine, 1.18 g (6.2 mmol) of p-toluenesulfonyl chloride was added, followed by stirring at room temperature for 24 hours. 100 ml of ethyl acetate was added to the reaction solution, and the mixture was washed with 3M hydrochloric acid. After concentrating the organic layer, dimethylformamide 10 ml, sodium hydride (60%
(Oily) 200 mg and stirred at room temperature for 3 hours. 3M
After neutralization with hydrochloric acid, the reaction product was extracted twice with 50 ml of ether, the extract was concentrated, and the obtained residue was subjected to silica gel column chromatography (hexane / ethyl acetate = 2).
(1R, 2S) -1-
540 mg (57% yield) of (4-bromophenyl) -1-cyano-2-hexylcyclopropane were obtained.

Colorless liquid [α] _D + 29.8 ° (C = 1.6, CHCl ₃ , 20
° C) IR (neat) 2950,2925,2850,2
230, 1490, 1460, 1380, 1115, 1
_{^{070,1005,820cm -1 1 H NMR (CDCl 3}} ) δ 0.89 (t, J =
6.9 Hz, 3H), 1.28 to 1.58 (m, 11
H), 1.66-1.75 (m, 2H), 7.14
(D, J = 8.7 Hz, 2H), 7.46 (d, J =
8.7 Hz, 2H) MS m / z 307 (M ^{++ 2,} 9), 305 (M ⁺ ,
9), 210 (15), 209 (98), 208 (15
9, 207 (100), 141 (14), 140 (1
3), 128 (26), 115 (16), 70 (1
6), 69 (14), 56 (22), 55 (26), 4
3 (53), 41 (69) Calculated m / z as high resolution MS C ₁₆ H ₂₀ BrN M ⁺ 305.0779, M ⁺⁺ 2 307.
0759 actual value M ⁺ 305.0795, M ⁺⁺ 2 307.
0759

(1-c) Synthesis of (1R, 2S) -1-cyano-2-hexyl-1- [4- (5-octylpyrimidin-2-yl) phenyl] cyclopropane In the above (1-b) 230 mg (0.75 mmol) of (1R, 2S) -1- (4-bromophenyl) -1-cyano-2-hexylcyclopropane obtained, 2-chloro-5
Octyl pyrimidine 170 mg (0.75 mmol),
Dichlorobis (triphenylphosphine) nickel 53
mg (10 mol%) of N, N-dimethylformamide 2
336 μl of hexabutylditin was added to the ml solution, and 8
Stirred at 0 ° C. for 4 hours. 2 ml of 3M hydrochloric acid was added, and then saturated sodium hydrogen carbonate was added to adjust the pH to 10, and the reaction product was extracted twice with 50 ml of ethyl acetate. After concentrating the organic layer, it was separated using silica gel column chromatography (hexane / ethyl acetate = 20/1).
Preparative high performance liquid chromatography (Tosoh, Sili
gel-60, 21.5 mm ID × 300 mm, hexane / ethyl acetate = 30/1)
(1R, 2S) -1-cyano-2-hexyl-1- [4
-(5-Octylpyrimidin-2-yl) phenyl] cyclopropane (31 mg, yield 10%) was obtained.

Colorless plate crystals Melting point 42 ° C. [α] _D + 33.5 ° (C = 0.9, CHCl ₃ , 20
° C) IR (KBr) 2950,2925,2850,22
_{^{40,1535,1430,800cm -1 1 H NMR (CDCl 3}} ) δ 0.88 (t, J =
7.0 Hz, 3H), 0.89 (t, J = 6.9 Hz,
3H), 1.24 to 1.43 (m, 8H), 1.48
(Dd, J = 7.2 and 5.1 Hz, 1H), 1.5
2 to 1.81 (m, 6H), 2.62 (t, J = 7.6)
Hz, 2H), 7.37 (d, J = 8.7 Hz, 2
H), 8.39 (d, J = 8.7 Hz, 2H), 8.6
2 (s, 2H) MS m / z 418 (M ^{++ 1,} 30), 417 (M ⁺ ,
88), 335 (19), 332 (17), 320 (4
8), 319 (100), 262 (17), 235 (2
3), 234 (70), 22 (17), 221 (9
2), 220 (729, 193 (22), 57 (2
1), 55 (32), 43 (88), 41 (86) Elemental analysis: C ₂₈ H ₃₉ N ₃ Calculated: C, 80.53%; H, 9.41%; N, 1
0.06% found: C, 80.43%; H, 9.38%; N, 1
0.35%

Example 2 Preparation of SC ^* Liquid Crystal Composition An SC parent liquid crystal (H-1) having the following composition was prepared.

[0073]

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The phase transition temperature of the base liquid crystal was as follows. Phase transition temperature (° C) Cr12.5 SC55.5 SA6
4.5 N70 I 95% of this base liquid crystal (H-1) and (No.
SC ^* liquid crystal composition (M-1) comprising 5% of compound 1)
Was prepared. The phase transition temperature was as follows.

Phase transition temperature (° C.) SC ^* 45 SA61.
5N ^* 64I The melting point was not clear. Similarly, an SC ^* liquid crystal composition (M-2) composed of 90% of the SC parent liquid crystal (H-1) and 10% of the compound of (No. 1) was prepared. The phase transition temperature was as follows.

Phase transition temperature (° C.) SC ^* 37 SA60.
5N ^* 62I

Example 3 Production of Liquid Crystal Display Element The SC ^* liquid crystal composition (M-1) obtained in Example 2 was heated to an isotropic liquid (I) phase, and this was heated to a thickness of 2 μm. A glass cell composed of two transparent electrode plates (polyimide coating-aligned by rubbing) was filled to prepare a display element. When this was gradually cooled to room temperature, a cell of SC ^* phase which was uniformly oriented was obtained. When a rectangular wave with an electric field strength of 10 V _pp / μm and 50 Hz was applied to this cell, and its electro-optical response speed was measured,
A high-speed response of 50 μsec at 25 ° C. was confirmed. At this time, the tilt angle was 19.0 °, and the contrast was very good. The spontaneous polarization was +6.8 nC / cm ² .

Similarly, SC ^* liquid crystal composition (M-2)
Was used to produce a liquid crystal display element, and its characteristics were measured. The results were as follows. (M-2): response: 25 μs, spontaneous polarization: +10.1 nC
/ Cm ² , tilt angle: 11.2 °, good contrast

(Comparative Example) SC Base Liquid Crystal (H-1) 95%
And an ester-based formula (R) having an optically active lactone ring

[0080]

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An SC ^* liquid crystal composition (N-1) comprising 5% of the above compound was prepared. The phase transition temperature was as follows. Phase transition temperature (° C) SC ^* 63 SA73 N ^* 79.5
I. A cell was fabricated in the same manner, and the electro-optical characteristics were measured. The response was 79 μs, which was slower than (M-1). The spontaneous polarization is +7.4 nC / cm ² and the tilt angle is 2
5.5 ゜.

[0082]

The optically active compound represented by the general formula (I) of the present invention has excellent compatibility with other liquid crystal compounds, and can induce large spontaneous polarization only by adding a small amount as a chiral dopant. Thus, a liquid crystal composition capable of high-speed response in a wide temperature range and having excellent alignment properties can be obtained.

The compound of the general formula (I) of the present invention
It is very practical because it can be easily produced industrially, is colorless and has excellent chemical stability against water, light and the like. Further, the chiral smectic liquid crystal composition of the present invention can realize a high-speed response of 30 μsec or less, and is extremely useful as a constituent material of a light switching element for display.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuo Kusumoto 1-9-2-102 Minamidai, Sagamihara City, Kanagawa Prefecture (72) Inventor Kenichi Sato 35-11 Kamimizo, Sagamihara City, Kanagawa Prefecture (72) Inventor Akiko Nakayama Tokyo 1380-K-702, Yamazaki-cho, Machida-shi (72) Inventor Yellow, Alberta, Canada Edmonton, 26-10525-83 (58) Fields investigated (Int. Cl. ⁷ , DB name) C07D 239/26 C07D 239 / 34 C09K 19/34 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A compound of the general formula (I) (In the formula, R ¹ represents 1 carbon atom which may be substituted by a fluorine atom or an alkoxyl group having 1 to 10 carbon atoms.)
X represents a single bond or -O-, m represents 0 or 1, and ring A is a 1,4-phenylene group or trans-1, which may be substituted by a fluorine atom. Represents a 4-cyclohexylene group, R ² represents an alkyl group having 1 to 10 carbon atoms, and the asymmetric carbon atoms at the 1- and 2-positions of the cyclopropane ring are each independently
(R) or (S) arrangement. An optically active compound represented by the formula: 2. The optically active compound according to claim 1, wherein m = 0. 3. A liquid crystal composition containing the optically active compound represented by the general formula (I) according to claim 1. 4. The liquid crystal composition according to claim 3, which exhibits a ferroelectric chiral smectic phase.