JPH08157409A - Optically active compound having 5-substituted-2-alkynyloxy group and liquid crystal composition - Google Patents

Abstract

(57) [Summary] (Corrected) [Constitution] General formula (I) Specifically, for example And a liquid crystal composition containing the compound. [Effect] It has excellent chemical stability against water, light, etc., and can be easily manufactured industrially. Further, it has low viscosity and excellent liquid crystallinity. Therefore, by adding a small amount to the host liquid crystal exhibiting the SC phase, it is possible to obtain a ferroelectric liquid crystal composition having a fast response in a wide temperature range although the spontaneous polarization is small. A ferroelectric liquid crystal composition containing this compound exhibits a high-speed response of about 400 μsec or less. Therefore, it is useful as a material for a liquid crystal optical switching element for display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel optically active liquid crystal compound and a liquid crystal composition containing the same, and more particularly to a ferroelectric liquid crystal display material excellent in response and memory property. .

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used at present due to their excellent features (low voltage operation, low power consumption, thin display, can be used even in bright places and do not cause eye strain). However, in the TN type, which is the most general display method, the response is extremely slow compared with other light emitting display methods such as CRT, and the display memory (memory effect) is obtained when the applied electric field is cut off. Because there is no
There are many restrictions on application to moving screens such as optical shutters that require high-speed response, printer heads, or televisions that require time-division driving, and it cannot be said that this is a suitable display method.

Recently, a display method using a ferroelectric liquid crystal has been reported. According to this, when the display method using a ferroelectric liquid crystal is used, it has a high speed response of 100 to 1000 times that of a TN type liquid crystal and a memory effect. Therefore, it is expected as a next-generation liquid crystal display element, and research and development are being actively conducted at present.

Ferroelectric liquid crystals belong to the tilt-type chiral smectic phase as the liquid crystal phase, of which the chiral smectic C (hereinafter abbreviated as SC ^* ) phase has the lowest viscosity and is most desirable. A large number of liquid crystal compounds exhibiting the SC ^* phase have already been synthesized and studied, but various conditions for use as a ferroelectric liquid crystal device (wide operating temperature range, good orientation, bistable (memory) property, low viscosity, high speed) There is no known compound which alone satisfies the responsiveness). Therefore, it is necessary to mix several or more kinds of compounds and use them as a liquid crystal composition showing an SC ^* phase (hereinafter, abbreviated as SC ^* liquid crystal composition).

The SC ^* liquid crystal composition is prepared by using an achiral compound and smectic C (hereinafter referred to as SC
The method of adding a dopant composed of an optically active compound as a so-called chiral dopant to a host liquid crystal exhibiting a phase is the most general because a composition having a lower viscosity can be obtained and a high-speed response is possible. Target.

Among the various physical properties of the SC ^* liquid crystal composition, the spontaneous polarization and the helical pitch greatly depend on the chiral dopant, but the spontaneous polarization is particularly important. Generally, the response time of a ferroelectric liquid crystal is proportional to viscosity and inversely proportional to spontaneous polarization.
The larger the spontaneous polarization is, the faster the response becomes. However, in reality, the larger the spontaneous polarization is, the more the viscosity is increased. Therefore, in many cases, the speed is not increased so much. It is also known that large spontaneous polarization adversely affects the memory property and the like. Therefore, it is important that the spontaneous polarization is suppressed as small as possible and a high-speed response is possible. Therefore, a low-viscosity SC ^* liquid crystal composition is desired.

Therefore, the compound used as the chiral dopant is required to have a viscosity as low as possible so as not to increase the viscosity of the liquid crystal composition obtained by the addition.
The compound is not necessarily required to exhibit the SC ^* phase or even the liquid crystal phase by itself, but in order to obtain a liquid crystal composition exhibiting the SC ^* phase in a wide temperature range when added to the host liquid crystal, the compound is a liquid crystal phase, preferably SC ^*. It is preferred to exhibit phases.

In order for the chiral dopant to induce spontaneous polarization, an asymmetric carbon in the compound molecule and a dipole close to it are necessary. The dipole is a carbonyl group, ether oxygen or a halogen atom such as chlorine or fluorine. Is usually used. Among these, it is known that an optically active compound using a fluorine atom as a dipole has a relatively low viscosity, and many have been synthesized so far (Japanese Patent Application Laid-Open No. 62-111939, JP-A-62-119939). Kaisho 63-2204
No. 2, JP-A-63-190842, JP-A-1
-27257, JP-A-2-311431,
JP-A-2-231473).

However, when these fluorine-based optically active liquid crystalline compounds are added to the host liquid crystal, a sufficient high-speed response cannot be expected with a small amount of addition, and if they are added to such an extent that high-speed response is possible. There is a problem that the temperature range or phase series of the composition is adversely affected, or the spontaneous polarization becomes large.

[0010]

The problem to be solved by the present invention is that even though its spontaneous polarization is extremely small, it has a low viscosity which enables a high-speed response by adding it as a chiral dopant to a host liquid crystal. It is an object of the present invention to provide a novel optically active compound, and to provide a ferroelectric liquid crystal display material containing the compound and exhibiting a high-speed response in a wide temperature range. Another object is to provide a general method for producing the novel compound.

[0011]

In order to solve the above problems, the present invention provides the following general formula (I):

[0012]

Embedded image

(Wherein R¹Is one or more fluorine
An atom or an alkoxyl group having 1 to 12 carbon atoms
Optionally substituted alkyl having 1 to 18 carbon atoms
A group or an alkoxyl group, an alkyl group having 2 to 18 carbon atoms
Kenyl group or alkenyloxy group having 3 to 18 carbon atoms
And m is 0 or 1, and is ring A, ring B or ring C
Are each independently substituted by one or two fluorine atoms.
Optionally substituted 1,4-phenylene group, pyrimidine
-2,5-diyl group, pyridine-2,5-diyl group, pi
Radine-2,5-diyl group, pyridazine-3,6-diii
Group, 1,3-dioxane-2,5-diyl group or tiger group
Represents a -1,4-cyclohexylene group, Y and Z
Are each independently a single bond, -CH₂CH₂-, -C≡C
-, -CH ₂O- or -OCH₂Represents-, W is fluorine
Atom, -OH, -OCH₃Or -OCF₃And R²
Represents an alkyl group having 1 to 18 carbon atoms, and * represents
Indicates that the carbon atom is an optically active asymmetric carbon atom.
You. ) 5-substituted-2-alkynyloxy group represented by
An optically active liquid crystalline compound having:

In the general formula (I) according to the present invention, R ¹
Is preferably an alkyl group or an alkoxyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms or an alkenyloxy group having 3 to 18 carbon atoms, and a straight chain having 6 to 12 carbon atoms. More preferably, it represents an alkyl group or an alkoxyl group, among which,
A linear alkyl group having 6 to 12 carbon atoms is particularly preferable. When ring A represents a trans-1,4-cyclohexylene group or a 1,3-dioxane-2,5-diyl group, R ¹ is an alkyl group having 1 to 18 carbon atoms or 2 to 18 carbon atoms. It is preferred to represent the alkenyl group of When m = 1, the compound represented by the general formula (I) is tricyclic, and the temperature range of the liquid crystal phase is wide, but the viscosity is slightly high. Therefore, in order to reduce the viscosity, the general formula (I It is preferred that the compounds of I) are bicyclic, ie m = 0. Ring A, ring B and ring C are each independently a 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,3-difluoro-
A 1,4-phenylene group or a pyrimidine-2,5-diyl group is preferred, and at least one of them is preferably a 1,4-phenylene group, but ring A
Is a pyrimidine-2,5-diyl group and ring C is 1,4
A —phenylene group is more preferred, and ring A, ring B and ring C preferably have no more than one heterocycle. Both Y and Z are preferably single bonds. Further, W preferably represents a fluorine atom or —OH, more preferably a fluorine atom. Further, R ² is preferably a linear alkyl group having 1 to 10 carbon atoms.

In the general formula (I), m, ring A, ring B,
Although many structures are possible as the central skeleton (core) by selecting the rings C, Y, and Z, m = 0, that is, compounds of the general formulas (Ia), (Ib), and (Ic) which are bicyclic compounds. )

[0016]

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(Wherein R ¹ , W, R ² and * have the same meanings as in the general formula (I), and in the general formula (Ic), one 1,4-phenylene group is one or two. Which may be substituted with a fluorine atom of formula (I), is a compound of formula (I), in which m = 1, that is, a tricyclic compound of formulas (Id) to (Ih).

[0018]

[Chemical 4]

(Wherein R ¹ , W, R ² and * have the same meanings as in the general formula (I), and the general formula (Id) to
In (Ih), one 1,4-phenylene group may be substituted with one or two fluorine atoms. )
Are preferred, and in the compounds represented by the above general formulas (Ia) to (Ih), general formulas (Ia), (Ib) and (I
c) is particularly preferred, and general formula (Ia) is most preferred.

The present invention also provides a liquid crystal composition containing an optically active compound represented by formula (I). The liquid crystal composition of the present invention contains at least one kind of the optically active compound of the general formula (I) as a constituent component,
Especially for ferroelectric liquid crystal display, SC ^* liquid crystal obtained by adding at least one compound of the above-mentioned general formula (I) as a part or all of the chiral dopant to the host liquid crystal showing the SC phase as the main component. A composition is desirable.

The content of the compound of formula (I) in the liquid crystal composition of the present invention is preferably in the range of 1 to 30% by weight, particularly preferably 2 to 15% by weight.

Further, the compound of the general formula (I) of the present invention is
By adding a small amount to a liquid crystal material exhibiting a nematic phase, it can be used as a TN type liquid crystal for preventing so-called reverse domain, or for use as an STN type liquid crystal. When used as a nematic liquid crystal material in this way,
In the general formula (I), R ¹ and R ² have 1 to 7 carbon atoms.
Is preferably a straight chain alkyl group, m is preferably 0, and ring A is preferably a 1,4-phenylene group or a trans-1,4-cyclohexylene group.

The compound of the general formula (I) of the present invention has the general formula (II) having a corresponding 2-propynyloxy group.

[0024]

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(Wherein R ¹ , m, ring A, ring B, ring C, Y
And Z have the same meaning as in formula (I). )
It can be easily produced from the compound represented by

The general formula (II) is converted to the general formula (III) by using a strong base such as butyl lithium as an anion.

[0027]

[Chemical 6]

By reacting with an optically active oxirane represented by the formula (wherein R ² and * have the same meanings as in formula (I)), W in formula (I) is reacted.
Is a compound of the formula —OH, a general formula (Iw)

[0029]

[Chemical 7]

(Wherein R ¹ , m, ring A, ring B, ring C,
Y, Z, R ² and * have the same meanings as in formula (I). ) The compound represented by this formula can be obtained.
By reacting this general formula (Iw) with a fluorinating agent such as dimethylaminosulfur trifluoride (DAST),
In the general formula (I), W is a compound having a fluorine atom.

[0031]

Embedded image

(Wherein R ¹ , m, ring A, ring B, ring C,
Y, Z, R ² and * have the same meanings as in formula (I). A compound represented by the formula (1) can be produced. Further, by reacting the general formula (Iw) with a methylating agent such as methyl iodide in the presence of a base, the general formula (Iy) in which W in the general formula (I) is —OCH ₃ is represented.

[0033]

[Chemical 9]

(Wherein R ¹ , m, ring A, ring B, ring C,
Y, Z, R ² and * have the same meanings as in formula (I). A compound represented by the formula (1) can be produced. Further, by reacting the general formula (I-w) with S-alkyldithiocarbonic acid chloride to form a dithiocarbonic acid ester, and reacting this with a fluorinating agent, a compound of the general formula (I) in which W is —OCF ₃ is obtained. Certain general formula (Iz)

[0035]

[Chemical 10]

(Wherein R ¹ , m, ring A, ring B, ring C,
Y, Z, R ² and * have the same meanings as in formula (I). A compound represented by the formula (1) can be produced. Here, the compound of the general formula (II) is a compound of the general formula (IV)

[0037]

[Chemical 11]

(In the formula, R ¹ , m, ring A, ring B, ring C, Y
And Z have the same meaning as in formula (I). )
Can be easily obtained by reacting with propargyl bromide in the presence of a base.

Here, the general formula (I
Many of the compounds V) are known as intermediates for producing liquid crystal compounds, and can be produced by ordinary production methods.

On the other hand, some of the optically active oxiranes of the general formula (III) are commercially available, and non-commercially available derivatives can be easily produced from commercially available optically active epichlorohydrin.

The compounds of the general formula (I) of the present invention can be obtained as described above. Specific compounds belonging to these compounds have a phase transition temperature such as a melting point and an infrared absorption spectrum (IR). , Nuclear magnetic resonance spectrum (NMR), mass spectrum (MS) and the like.

Table 1 shows typical examples of the compounds of the general formula (I) thus obtained.

[0043]

[Table 1]

(In the table, Cr represents a crystalline phase, and I represents an isotropic liquid phase.) As can be seen from Table 1, the compound of the general formula (I) does not necessarily show a liquid crystal phase, but the host liquid crystal S when added
The temperature range of the C ^* liquid crystal composition is not so badly affected.

The SC ^* liquid crystal composition obtained by adding the compound of the general formula (I) to the host liquid crystal is
High-speed response is possible by applying an electric field. For example, the first
10% by weight of the compound (Ia-x-1) in the table and a phenylpyrimidine host liquid crystal (H)

[0046]

[Chemical 12]

(In the formula, "%" represents "% by weight".)
In SC ^* liquid crystal composition (M-1) consisting of 90% by weight,
Although the spontaneous polarization at 25 ° C. was as small as 0.1 nC / cm ² or less, it exhibited a high-speed response of 440 μsec. From this, it is understood that the viscosity of the compound of the general formula (I) is very small.

On the other hand, the formula (R-1) described in JP-A-63-22042 is used.

[0049]

[Chemical 13]

10% by weight of the compound of and the host liquid crystal (H)
SC ^* liquid crystal composition (N-1) consisting of 90% by weight was prepared. A cell was similarly prepared using this (N-1), and its electro-optical response was measured at 25 ° C., and a high-speed response of 110 μsec was confirmed, but spontaneous polarization was −5.4 nC / cm. ^It has become very big as ² .

From the above, it can be understood that the viscosity of the compound of the general formula (I) is very small. When the compound of the general formula (I) of the present invention is added as a chiral dopant, the SC compound used in the host liquid crystal is, for example, the following general formula (A).

[0052]

Embedded image

(In the formula, R ^a and R ^b each independently represent a linear or branched alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkanoyloxy group or an alkoxycarbonyloxy group, and they are the same as each other. Phenylbenzoate-based compound represented by the formula (B)

[0054]

[Chemical 15]

A phenylpyrimidine compound represented by the formula (wherein R ^a and R ^b have the same meanings as in formula (A)) can be given. In addition, the general formula (C) including the general formulas (A) and (B)

[0056]

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(In the formula, R ^a and R ^b have the same meanings as in the general formula (A), and the ring L and the ring M are each independently a 1,4-phenylene group, a 1,4-cyclohexylene group, Pyridine-2,5-diyl group, pyrimidine-2,5
Represents a diyl group, a pyrazine-2,5-diyl group, a pyridazine-3,6-diyl group, a 1,3-dioxane-2,5-diyl group or a halogen-substituted product thereof, which may be the same or different. And Z ^a is -COO
-, - OCO -, - CH 2 O -, - OCH 2 -, - CH 2
Represents CH ₂ —, —C≡C— or a single bond. The compound represented by () can be used for the same purpose.

For the purpose of expanding the temperature range showing the SC phase to a high temperature range, the general formula (D)

[0059]

[Chemical 17]

(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). , May be the same as or different from each other, and Z ^a and Z ^b each independently have the same meaning as Z ^a in the general formula (C), and may be the same or different from each other.) A tricyclic compound represented by can be used.

It is effective that these compounds are mixed and used as a liquid crystal composition exhibiting an SC phase. However, it is only necessary to exhibit the SC phase as a composition, and each compound does not necessarily exhibit the SC phase. No need.

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

The SC ^* liquid crystal composition obtained by adding the compound of the general formula (I) of the present invention to the host liquid crystal exhibiting the SC phase forms a thin film of about 1 to 20 μm between two transparent glass electrodes. By enclosing it, it can be used as a display cell. In order to obtain good contrast, it is necessary that the liquid crystal material has a uniformly aligned monodomain. Many methods have been attempted in order to obtain good orientation, but as a liquid crystal material, from the high temperature side, I (isotropic liquid) phase-N ^* (chiral nematic) phase-SA (smectic A) phase-SC.
^It indicates a phase sequence of ^* phase or I phase-SA phase-SC ^* phase, and it is necessary that the spiral pitch in the N ^* phase and the SC ^* phase is large. In order to increase the spiral pitch, generally, a method of mixing an appropriate amount of chiral compounds having opposite twist directions is used, but in the compound of the general formula (I) of the present invention, the induced spiral pitch is so small. The adjustment is easy because it is not provided.

[0064]

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

The phase transition temperature was measured by using a polarizing microscope equipped with a temperature adjusting stage and a differential scanning calorimeter (DSC). The structure of the compound is NMR, IR,
Confirmed by MS and elemental analysis. (Ne in IR
(at) indicates the measurement by the liquid film, and (KBr) indicates the measurement by the tablet molding. CDCl _{3 in} NMR represents a solvent, s is a singlet, d is a doublet, t is a triplet, quin.
tet represents a quintuplet, m represents a multiplet, and, for example, dt
Represents a doublet triplet, and broad represents broad absorption. M ^{+ in} MS represents the parent peak, and the value in parentheses represents the relative intensity of that peak. Temperature represents ° C and all "%" in the composition represent "wt%". (Example 1) 2- [4- (2-propynyloxy)
Synthesis of Phenyl] -5-decylpyrimidine

[0066]

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4- (5-decylpyrimidin-2-yl)
A solution of 2.0 g of phenol, 884 mg of potassium carbonate, 914 mg of propargyl bromide, and 0.5 mg of ferric chloride in 15 ml of acetone was heated under reflux for 2 hours under an argon stream. After completion of the reaction, the reaction mixture was filtered through Celite, and a 10% aqueous sodium hydroxide solution was added to the filtered solution. The organic layer was extracted with dichloromethane, concentrated, and then purified using column chromatography (Wakogel C-300, hexane / ethyl acetate = 5/1) to give 2- [4- (2-propynyloxy) phenyl]. 2.01 g (yield 90%) of -5-decylpyrimidine was obtained. Further, it was recrystallized from hexane to obtain 1.81 g of crystals (yield 81%). Colorless columnar crystals, melting point 57 ° C. IR (KBr) 3281,2926,2852,16
07, 1586, 1543, 1512, 1429, 13
83, 1248, 1169, 1019, 847, 799
_{^{cm -1 1 H NMR (CDCl 3}} ) δ 0.88 (t, J =
6.9 Hz, 3H), 1.26 to 1.35 (m, 14
H), 1.63 (quintet, J = 7.6 Hz, 2
H), 2.54 (t, J = 2.4 Hz, 1H), 2.6
0 (t, J = 7.6 Hz, 1H), 4.77 (d, J =
2.4Hz, 2H), 7.07 (d, J = 9.0Hz,
2H), 8.38 (d, J = 9.0Hz, 2H), 8.
58 (s, 2H) MS m / z 350 (M ⁺ , 100), 311 (3
2), 237 (21), 224 (19), 185 (1
5), 156 (12), 43 (38), 41 (33) High-resolution MS C ₂₃ H ₃₀ N ₂ O Calculated value m / z 350.2356 Measured value m / z 350.2337 (Example 2) (Example 2) R) -2- [4- (5-Hydroxy-2-undecynyloxy) phenyl] -5-decylpyrimidine (compound of (Ia-w-1) in Table 1)

[0068]

[Chemical 19]

2- [4- (2-propynyloxy) phenyl] -5-decylpyrimidine 42 obtained in Example 1 above
To 9 mg of a toluene 2 ml solution, a 1.6 M butyllithium-hexane solution 0.09 ml was added at -78 ° C, and the mixture was stirred for 30 minutes. After completion of the reaction, a solution of 23 mg of (R) -1,2-epoxyoctane in 0.5 ml of toluene was added dropwise over 15 minutes, 0.02 ml of boron trifluoride diethyl etherate was subsequently added, and -50 over 1 hour. The temperature was raised to ° C. The mixture was treated with saturated brine, extracted with ethyl acetate, concentrated, and the residue was purified by column chromatography (hexane / ethyl acetate = 5/1) to give (R) -2- [4-
45 mg of (5-hydroxy-2-undecynyloxy) phenyl] -5-decylpyrimidine was obtained (yield 78%). Recrystallization from hexane gave 40 mg of crystals (yield 69%, 89% ee). Colorless columnar crystal Melting point 55 ° C. [α] _D ²⁰ -3.2 ° (c = 0.74, CHCl ₃ ) IR (neat) 3437,2922,2853,1
607, 1588, 1541, 1433, 1377, 1
256, 1173, 1011, 851, 797 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.86 (t, J =
7.1 Hz, 3 H), 0.88 (t, J = 6.7 Hz,
3H), 1.20 to 1.68 (m, 26H), 1.78
(D, J = 5.2 Hz, 1 H), 2.36 (ddt, J
= 16.7, 6.7, 2.0 Hz, 1H), 2.47
(Ddt, J = 16.7, 4.8, 2.0 Hz, 1
H), 2.60 (t, J = 7.6 Hz, 2H), 3.6
9 to 3.76 (m, 1H), 4.77 (t, J = 2.1)
Hz, 2H), 7.06 (d, J = 9.0Hz, 2
H), 8.37 (d, J = 9.0 Hz, 2H), 8.5
8 (s, 2H) MS m / z 478 (M ⁺ , 22), 364 (1
1), 313 (27), 312 (91), 199 (8
0), 186 (75), 185 (100), 158 (3
1), 69 (10), 43 (37), 41 (33) High-resolution MS C ₃₁ H ₄₆ N ₂ O ₂ Calculated value m / z 478.3557 Measured value m / z 478.3562 (Example 3) (S) -2- [4- (5-fluoro-
Synthesis of 2-undecynyloxy) phenyl] -5-decylpyrimidine (compound of (Ia-x-1) in Table 1)

[0070]

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(R) -2- [4- obtained in Example 2 above
To a solution of 14.5 mg of (5-hydroxy-2-undecynyloxy) phenyl] -5-decylpyrimidine in 1 ml of dichloromethane, 1.0 M dimethylaminosulfur trifluoride (DAST) -dichloromethane solution at −78 ° C. 0.0
5 ml was added and stirred for 30 minutes. After completion of the reaction, water was added to the reaction solution, which was extracted with ether and concentrated, and then separated and purified by column chromatography (Wakogel C-300, hexane / ethyl acetate = 15/1), (S) -2.
-[4- (5-Fluoro-2-undecynyloxy) phenyl] -5-decylpyrimidine 8.8 mg (yield 61
%) Was obtained. Recrystallized from ethanol to give 8.0
mg (yield 57%) was obtained. Colorless needle crystal melting point 54 ° C. [α] _D ²⁰ -6.2 ° (c = 0.64, CHCl ₃ ) IR (KBr) 3430, 2924, 2853, 15
88, 1431, 1248, 1175, 1011, 79
_{^{1cm -1 1 H NMR (CDCl 3}} ) δ 0.86 (t, J =
7.0 Hz, 3 H), 0.88 (t, J = 6.7 Hz,
3H), 1.26 to 1.53 (m, 22H), 1.59
˜1.70 (m, 4H), 2.54 to 2.66 (m, 4)
H), 4.57 (dm, J = 48Hz, 1H), 4.7
6 (t, J = 2.1 Hz, 2H), 7.05 (d, J =
9.0Hz, 2H), 8.37 (d, J = 9.0Hz,
2H), 8.58 (s, 2H) MS m / z 481 (M ⁺⁺ 1,35), 480.
(M ⁺ , 100), 409 (10), 364 (25),
312 (46), 185 (26), 158 (6), 43
(15) Calculated value as high resolution MS C ₃₁ H ₄₅ N ₂ OF m / z 480.3513 Measured value m / z 480.3524 (Example 4) Preparation of SC ^* composition (1)

[0072]

[Chemical 21]

A host liquid crystal (H) having an SC phase consisting of was prepared. The phase transition temperature of this host liquid crystal (H) was as follows. 12.5 ° C (Cr → SC), 55.5 ° C (SC-S
A), 64.5 ° C (SA-N), 70.0 ° C (N-I) 90% by weight of this host liquid crystal and (Ia-x- in Table 1).
SC ^* liquid crystal composition (M
-1) was prepared. The phase transition temperature was as follows. 47.0 ° C (SC ^* -SA), 59.0 ° C (SA-
N ^* ), 64.0 ° C. (N ^* -I) The melting point was not clear.

Further, S consisting of 85% by weight of the host liquid crystal (H) and 15% by weight of the compound (Ia-x-1) in Table 1.
A C ^* liquid crystal composition (M-2) was prepared. The phase transition temperature was as follows. 43.0 ° C (SC ^* -SA), 55.5 ° C (SA-
N ^* ), 60.5 ° C (N ^* -I) The melting point was not clear. (Comparative Example 1) 90% by weight of host liquid crystal and formula (R-1)

[0075]

[Chemical formula 22]

An SC ^* liquid crystal composition (N-1) containing 10% by weight of the compound of the above was prepared. The phase transition temperature of this composition was as follows. 54.5 ° C (SC-SA), 67.0 ° C (SA-N),
69.5 ° C. (N−I) (Example 5) Preparation of Liquid Crystal Display Device The SC ^* liquid crystal composition (M-1) obtained in Example 4 was heated to an isotropic liquid (I) phase, and this was heated. Fill a glass cell consisting of two transparent electrode plates (polyimide coating-aligned by rubbing) with a thickness of 2 μm, and add S
The display element was manufactured by gradually cooling until it showed the C ^* phase.

Electric field strength of 10 V _pp / μm, 5
When a rectangular wave of 0 Hz was applied and the electro-optical response was measured, a high-speed response of 440 μsec at 25 ° C. was confirmed. At this time, the tilt angle was 15 °, and the contrast was good. When a spontaneous polarization was measured by applying a triangular wave, it was 0.1 nC / cm ² or less, which was very small, indicating that the viscosity of this liquid crystal composition was very small.

Similarly, SC ^* liquid crystal composition (M-2)
A cell was prepared by using and the response speed was measured and found to be 370 μsec. (Comparative Example 2) SC ^* liquid crystal composition (N- obtained in Comparative Example 1)
Using 1), a cell was prepared in the same manner as in Example 5, and its electro-optical response was measured.
We were able to confirm a high-speed response of seconds. However, the spontaneous polarization is -5.4 nC / as compared with the case of (M-1).
It has become so large as cm ² .

[0079]

INDUSTRIAL APPLICABILITY The compound represented by formula (I) of the present invention
An optically active compound having a substituted 2-alkynyloxy group has a low viscosity, and when added as a chiral dopant to a host liquid crystal exhibiting an SC phase, it has a high response speed in a wide temperature range although the spontaneous polarization is extremely small. A liquid crystal composition capable of achieving the above can be provided.

Further, the compound of the general formula (I) of the present invention is
It can be easily produced industrially, is colorless and has excellent chemical stability to water, light, etc., and is practical. Furthermore, by using the chiral smectic liquid crystal composition of the present invention, it is easy to realize a high-speed response of about 400 μsec or less, and it is extremely useful as an optical switching element for display.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09K 19/12 9279-4H 19/14 9279-4H 19/18 9279-4H 19/20 9279-4H 19/30 9279-4H 19/34 9279-4H 19/58 9279-4H G02F 1/13 500 1/141 (72) Inventor Kayoko Ito 2-618-2-1-602 (Iiyamamancho, Funabashi, Chiba Prefecture) 72) Inventor Hiyama Jojiro 4-29-3-101 Kamizuruma, Sagamihara City, Kanagawa Prefecture (72) Inventor Tetsuo Kusumoto 1-9-2-102, Minamidai, Sagamihara City, Kanagawa Prefecture (72) Kenichi Sato Sagamihara City, Kanagawa Prefecture Kamimizo 35-11 (72) Inventor Kumiko Ogino 23-1-702 Yotsuyakamimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa

Claims (13)

[Claims] 1. A compound represented by the general formula (I):(In the formula, R¹Is one or more fluorine atoms or
Substituted by an alkoxyl group having 1 to 12 carbon atoms
Alkyl groups having 1 to 18 carbon atoms or
Rucoxyl group, alkenyl group having 2 to 18 carbon atoms, or
Represents an alkenyloxy group having 3 to 18 carbon atoms, m
Represents 0 or 1, and ring A, ring B and ring C are each
Vertically substituted by one or two fluorine atoms,
Good 1,4-phenylene group, pyrimidine-2,5-di
Yl group, pyridine-2,5-diyl group, pyrazine-2,
5-diyl group, pyridazine-3,6-diyl group, 1,3
-Dioxane-2,5-diyl group or trans-1,4
Represents a cyclohexylene group, Y and Z are each independently
Vertically single bond, -CH₂CH₂-, -C≡C-, -CH ₂
O- or -OCH₂Represents-, W is a fluorine atom, -O
H, -OCH₃Or -OCF₃And R²Is a carbon atom
Represents an alkyl group of the number 1 to 18, where * is a carbon atom
Represents an optically active asymmetric carbon atom. )
Optically active compound. 2. The optically active compound according to claim 1, wherein in the general formula (I), Y and Z are both single bonds. 3. In the general formula (I), R ¹ is an alkyl group or an alkoxyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms or 3 to 18 carbon atoms.
3. The optically active compound according to claim 2, which represents the alkenyloxy group of 4. In the general formula (I), ring A, ring B and ring C are each independently a 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4.
An optically active compound according to claim 3, which represents a -phenylene group, a 2,3-difluoro-1,4-phenylene group or a pyrimidine-2,5-diyl group. 5. The optically active compound according to claim 4, wherein in the general formula (I), W represents a fluorine atom or —OH. 6. The optically active compound according to claim 5, wherein in the general formula (I), m is 0. 7. The optically active compound according to claim 6, wherein in the general formula (I), ring A is a pyrimidine-2,5-diyl group and ring C is a 1,4-phenylene group. Compound. 8. The optically active compound according to claim 7, wherein in the general formula (I), R ² is a linear alkyl group having 1 to 10 carbon atoms. 9. The optically active compound according to claim 8, wherein in the general formula (I), R ¹ is a linear alkyl group or alkoxyl group having 6 to 12 carbon atoms. 10. The optically active compound according to claim 9, wherein in the general formula (I), R ¹ is a linear alkyl group having 6 to 12 carbon atoms. 11. The general formula (I) according to any one of claims 1 to 10.
A liquid crystal composition containing an optically active compound represented by: 12. The liquid crystal composition according to claim 11, which exhibits a ferroelectric chiral smectic phase. 13. A liquid crystal display device comprising the liquid crystal composition according to claim 11.