JP2819038B2 - Optically active compound, intermediate thereof, liquid crystal composition and liquid crystal display device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel optically active compound, an intermediate thereof, a liquid crystal composition and a liquid crystal display element, and particularly to a ferroelectric substance having excellent responsiveness and excellent memory properties. The present invention relates to a liquid crystal display material.

(Prior art)

Liquid crystal display devices are currently widely used due to their excellent features (low voltage operation, low power consumption, thin display, use in bright places, and no eyestrain). However, the most common TN type display method is CRT
Response is extremely slow compared to light-emitting display methods such as
Also, since the display memory (memory effect) cannot be obtained when the applied electric field is turned off, optical shutters that require high-speed response, printer heads, and televisions that require time-sharing drive are often used for moving images. Therefore, it was not a suitable display method.

Recently, Meyer et al. Reported a display method using a ferroelectric liquid crystal.According to this method, a high-speed response and memory effect of 100 to 1000 times that of a TN type liquid crystal can be obtained. Research and development are being actively pursued.

The ferroelectric liquid crystal belongs to a tilt type chiral smectic phase as a liquid crystal phase, but practically, chiral smectic C (hereinafter referred to as Sc ^*) having the lowest viscosity among them ^.
Is abbreviated. ) Phase is most desirable.

Many liquid crystal compounds exhibiting the Sc ^* phase have already been synthesized and studied. However, the following conditions for use as a ferroelectric display device require the following conditions: (a) Sc in a wide temperature range including room temperature.
^{* In order} to show phase and (b) obtain good orientation, Sc ^*
Having an appropriate phase series on the high temperature side of the phase and having a large helical pitch, (c) having an appropriate tilt angle,
It is preferable that (d) the viscosity is small and (e) the spontaneous polarization is large to some extent, but none of them satisfy these requirements alone.

For this reason, a liquid crystal compound exhibiting the Sc ^* phase (hereinafter referred to as Sc ^* compound) or the like is mixed and used as a liquid crystal composition exhibiting the Sc ^* phase (hereinafter referred to as Sc ^* liquid crystal composition). However, it is necessary for the liquid crystal compound exhibiting the Sc ^* phase to have low viscosity and to have a spontaneous polarization larger than a certain level in order to realize a high-speed response.

Further, it can be used as a Sc ^* composition by adding it to a liquid crystal compound or a composition exhibiting another smectic C (hereinafter referred to as Sc) phase as a chiral dopan,
In this case, since the viscosity can be reduced, a higher-speed response is possible, which is generally used. The compound used as a chiral dopan does not necessarily have to exhibit the Sc ^* phase by itself, but it is necessary for the composition to exhibit similar properties.

[Problems to be solved by the invention]

The conventional liquid crystal compound exhibiting the Sc ^* phase is insufficient in viscosity and spontaneous polarization, and has a problem in providing a liquid crystal material with high response speed, and its improvement has been desired.

The problem to be solved by the present invention is particularly Sc phase or
By adding as a chiral dopant to the host liquid crystal showing Sc ^* phase, we can provide optically active compounds that can induce large spontaneous polarization and provide ferroelectric liquid crystal display materials that can respond at high speed. It is to make.

It is known that in order to induce large spontaneous polarization, a group having a strong dipole moment needs to be as close as possible to the central skeleton (core) and asymmetric carbon of the liquid crystal molecule. A carbonyl group is generally used as a group having a strong dipole moment, but a cyano group can be cited as a stronger group. However, as a compound in which this cyano group is directly bonded to an asymmetric carbon, Is only known, and a compound in which a cyano group is directly connected to the core has not been known.

[Means for Solving the Problems] The present invention provides an optically active compound represented by the following general formula (I) in order to solve the above problems.

In the general formula (I), R ¹ represents an alkyl group or an alkoxyl group having 1 to 18 carbon atoms, and when asymmetric carbon is present due to branching, it may be optically active or racemic. But preferably 4 carbon atoms
And represents an alkyl group or an alkoxyl group, more preferably a linear alkoxyl group. R ² represents an alkyl group having 1 to 18 carbon atoms, more preferably a straight-chain alkyl having 1 to 8 carbon atoms.

m represents 0 (zero) or 1, and when m = 0, m = 1 is preferable because liquid crystallinity is deteriorated and the transition temperature of the composition tends to be lowered.

Are each independently (Trans-1,4-cyclohexylene group), , Preferably And particularly preferably Represents X represents a fluorine or chlorine atom, preferably a fluorine atom. Z is -COO -, - OCO -, - CH 2 O
—, —OCH ₂ —, —CH ₂ CH ₂ —, —C≡C— or a single bond, preferably a single bond. Y represents COO or CH ₂ O, preferably COO. C ^* represents an asymmetric carbon atom in the (R) or (S) configuration.

In the general formula (I), Y is COO; Wherein m is 1, Z is a single bond, It is preferred that R ¹ is an alkyl group or an alkoxyl group having 4 to 12 carbon atoms, and R ² is an alkyl group having 1 to 8 carbon atoms. In particular, R ² is preferably nC ₆ H ₁₃ , and at this time, R ¹ is more preferably nC ₈ H ₁₇ O.

The present invention also provides a liquid crystal composition using these novel compounds belonging to the general formula (I).

The liquid crystal composition according to the present invention contains at least one of the compounds of the above general formula (I) as a constituent, and the liquid crystal composition preferably exhibits a ferroelectric chiral smectic phase. In particular, for use in ferroelectric liquid crystal display, a Sc ^* liquid crystal obtained by adding at least one kind of the compound of the general formula (I) as a part or all of a chiral dopant to a base liquid crystal showing a Sc phase as a main component. Compositions are suitable.

Also, by adding a small amount to nematic liquid crystal, TN
It can be used for preventing so-called reverse domain as a liquid crystal, or for use as an STN liquid crystal.

In order to produce the optically active compound having a cyano group of the above general formula (I), an optically active compound represented by the following general formula (I ′) can be used as an intermediate.

(In the formula, R ² and C ^* represent the same as those in the general formula (I), and R ³ represents —OH or —OCH _3. ) When Y represents COO, the following general formula It can be easily produced by reacting a compound represented by the general formula (II), which is a compound belonging to (I '), with an acid chloride represented by the general formula (V) in the presence of a base such as pyridine. Alternatively, a compound represented by the general formula (II), which is a compound belonging to the general formula (I '), is reacted with a carboxylic acid represented by the general formula (VI) in the presence of a condensing agent such as dicyclohexylcarbodiimide (DCC). Can also be manufactured.
When Y represents CH ₂ O, a compound represented by the general formula (II), which is a compound belonging to the general formula (I ′), and a bromide represented by the general formula (VII) are treated with a base or silver tetrafluoroborate. The reaction can be carried out in the presence of a silver salt such as

(Where R ¹ , R ² , m X, Y, Z and C ^* represent the same as those of the general formula (I). Here, the optically active phenol derivative having a cyano group of the general formula (II) which is a compound belonging to the general formula (I ′) is also a novel compound, and the present invention belongs to the general formula (I ′). Also provided are compounds of general formula (II).

The compound of the general formula (II) can be produced as follows.

The tosyloxy group of the optically active compound represented by the general formula (III) is reduced and eliminated with a reducing agent such as sodium borohydride to give a compound represented by the general formula (IV), which is a compound belonging to the general formula (I '). Optically active compound
Next, the compound represented by the general formula (II) can be obtained by removing the methyl group using aluminum chloride, dimethyl sulfide, ethanethiol or the like.

Here, the optically active phenol derivative having a cyano group of the general formula (IV), which is a compound belonging to the general formula (I ′), is also a novel compound, and the present invention relates to a compound belonging to the general formula (I ′). Also provided is a compound of formula (IV).

(In the above formula, R ² is the same as that of the general formula (I).) On the other hand, the compound represented by the general formula (III) is prepared by converting 4-methoxyethanenitrile into a compound of the general formula (VIII) in the presence of a strong base. )
After reacting with an optically active epoxide represented by, each diastereomer is separated by ordinary separation means such as column chromatography, and further in the presence of a base such as pyridine,
It can be obtained by tosylating a hydroxyl group with a base P-toluenesulfonyl.

In the above formula, R ² , C ^* has the same meaning as in general formula (II), and C ^** independently of C ^* represents an asymmetric carbon in the (R) or (S) configuration.

As described above, the optically active compounds of the general formula (I) of the present invention can be obtained. The specific compounds belonging to these and the specific intermediates belonging to the general formula (II) have melting points, Phase transition temperature, infrared absorption spectrum (IR),
It can be confirmed by means such as nuclear magnetic resonance spectrum (NMR) and mass spectrometry (MS).

The compounds of the general formula (V) or (VI) are almost already known, and can be obtained by ordinary synthetic chemistry techniques. The compound of the general formula (VIII) can be obtained by reducing the compound of the general formula (V) and then brominating the compound.

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

One of the outstanding features of the compounds of general formula (I) is that
It can be mentioned that the spontaneous polarization (Ps) is sufficiently large.

For example, in a Sc ^* composition in which a compound shown in an example described later is added to a matrix liquid crystal exhibiting a Sc phase by 10%, Ps at 25 ° C.
The value is as large as 5.3 nC / cm ² . This is most commonly used as a source of asymmetry in liquid crystals (S) -2-
Sc ^* compound derived from methyl butanol, for example, (S) -2
It can be seen that -methylbutyl p-decyloxybenzylideneaminobenzoate (DOBAMBC) or the like alone is much larger than that of about 4 nC / cm ² . this is,
It is considered that the asymmetric center in the compound of the general formula (I) is directly connected to the central skeleton part (core) of the liquid crystal molecule and a cyano group having a strong dipole moment. If about 2 to 3% or more is added to the substance, spontaneous polarization sufficient for high-speed response can be induced.

The compound of the general formula (I) of the present invention is preferably used by being added to a liquid crystal composition, rather than being used alone. In that case, a chiral dopant comprising at least one optically active compound of the general formula (I) and, if necessary, another optically active compound is added to another liquid crystal compound or liquid crystal composition. In particular, when used as a ferroelectric liquid crystal display device, it is desirable to use a non-chiral liquid crystal compound showing a Sc phase as a main component or a composition in addition to a liquid crystal composition. Since the optically active compound of the general formula (I) can induce a sufficiently large spontaneous polarization, Sc
When added to the liquid crystal in an amount of 2 to 3% or more, a certain degree of spontaneous polarization is induced in the composition, and a high-speed response becomes possible. Since the compound of the general formula (I) alone shows the Sc ^* phase up to a considerably high temperature, addition of this compound does not narrow the temperature range of the Sc ^* phase.

Also, by adding a small amount to nematic liquid crystal, TN
Prevention of reverse domain that can be said as liquid crystal, or
It can also be used for applications such as STN liquid crystal.

The compound having an optically active group represented by the general formula (I) of the present invention should be used as a Sc liquid crystal composition for doping.
Examples of the Sc compound include a phenylbenzoate-based compound represented by the following general formula (A) and a pyrimidine-based compound represented by the general formula (B).

(In the formula, R ^a and R ^b represent a linear or branched alkyl group, alkoxyl group, alkoxycarbonyl group, alkanoyloxy group, or alkoxycarbonyloxy group, and may be the same or different.) (In the formula, R ^a and R ^b represent the same meaning as in the general formula A.)
Further, the compounds represented by the general formula (C), including the general formulas (A) and (B), can be used for the same purpose.

(Wherein, R ^a and R ^b have the same meanings as in the general formula A, (1,4-cyclohexylene group), Alternatively, these halogen-substituted compounds may be the same or different. Z ^a is -COO -, - OCO -, -
CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ —, —C≡C—, or a single bond. In order to expand the temperature range of the Sc phase to a high temperature range,
A tricyclic compound represented by the general formula (D) can be used.

(Wherein, R ^a and R ^b are the same as those in the general formula A, Is of the general formula (C) And may be the same or different,
Z ^a, Z ^b is a same as Z ^a of the the general formula (C), and may be the same or different. It is effective to mix these compounds to use as a Sc liquid crystal composition, but 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 represented by the general formula (I) of the present invention and, if necessary, another optically active compound as a chiral dopant to the Sc liquid crystal composition thus obtained, the compound can be easily applied over a wide temperature range including room temperature. A liquid crystal composition exhibiting the Sc ^* phase can be obtained.

The optically active compound of the general formula (I) of the present invention can be combined with other Sc
The liquid crystal composition obtained by doping the compound or the Sc liquid crystal composition can be used as a display cell by sealing it as a thin film of about 1 to 20 μm between two transparent glass electrodes. Thereby, the liquid crystal display device of the present invention can be substantially obtained. In order to obtain good contrast, it is necessary to form monodomains that are uniformly oriented. Many methods have been attempted for this purpose, but in order to exhibit good alignment, the liquid crystal material must be composed of N ^* phase and Sc ^*.
It is necessary to increase the helical pitch in the phase.
To increase the helical pitch, it is sufficient to mix an appropriate amount of chiral compounds having opposite twist directions. The helical pitch induced by the compound of the general formula (I) of the present invention is particularly high in the N ^* phase. The adjustment is easy because it is not short in the temperature range.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to Examples, but of course, the gist and scope of the present invention are not limited by these Examples.

The structure of the compound was determined by nuclear magnetic resonance spectrum (NM
R), infrared absorption spectrum (IR), and mass spectrum (MS). The phase transition temperature was measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DS).
(KBr) is measured by tablet molding, (neat) is measured by liquid film, (Nujol)
Represents the measurement in suspension in liquid paraffin, respectively. In NMR, (CDCL ₃ ) (CCl ₄ ) is a solvent, s is a singlet, d is a doublet, t is a triplet, q is a quadruple, m is a multiplet, and broad is a broad absorption. And J represents a coupling constant. M ^{+ in} MS represents the parent peak;
The numerical value in parentheses indicates the relative intensity of the peak. The temperature represents ° C. All percentages in the compositions represent percent by weight.

Reference Example 1 (2S, 4R) and (2R, 4R) -4-hydroxy-2- (4
Synthesis of -methoxyphenyl) decanenitrile To a solution of 750 mg of 4-methoxyphenylacetonitrile in 10 ml of tetrahydrofuran (THF) at −78 ° C. was added 3.3 ml of a 1.55 M hexane solution of butyllithium (n-BuLi), and 1
After stirring for an hour, (2R) -1,2-epoxyoctane 651 mg
Was added, and the temperature was raised to -10 ° C. A saturated aqueous ammonium chloride solution was added, and the mixture was extracted with ether, and then subjected to column chromatography (Kieselgel 60, hexane / ethyl acetate = 4/1) to give (2S, 4R) and (2R, 4R) -4-hydroxy-2- (4-methoxy). Phenyl) decanenitrile about 1:
926 mg (70% yield) of one mixture was obtained. The two products were further separated by medium pressure column chromatography.

 The identification data is shown below.

(2R, 4R) -4-hydroxy-2- (4-methoxyphenyl) decanenitrile Oil Rf 0.29 (hexane / ethyl acetate = 3/1) ▲ [α] ²⁰ _D ▼ -29.5 ゜ (c = 2.61, MeOH) ) IR (neat) 3450,2240,1610,1510,1250,1175,1030,825,6
_{^{25cm -1 1 H NMR (CDCl 3}} ) δ 0.88 (t, J = 7.0Hz, 3H), 1.22~1.54
(M, 10H), 1.65 (broad s, 1H), 1.80 (ddd, J = 13.9, 10.
5,4.4Hz, 1H), 1.98 (ddd, J = 13.9,11.5,2.4Hz, 1H), 3.3
9 (m, 1H), 3.81 (s, 3H), 4.01 (dd, J = 11.5,4.4Hz, 1
H), 6.90 (d, J = 8.7Hz, 2H), 7.27 (d, J = 8.7Hz, 2H) MS m / z: 275 (M +, 3.0), 159 (100) Elementary analysis: C ₁₇ H ₂₅ As NO ₂ Calculated: C, 74.14; H, 9.15; N, 5.09% Found: C, 73.84; H, 9.02; N, 4.81% (2R, 4R) -4-hydroxy-2- (4-methoxyphenyl) ) decane nitrile oil Rf 0.24 (hexane / ethyl acetate = 3/1) ▲ [α] ²⁰ _D ▼ -20.8 DEG (c = 2.06, MeOH) IR (neat) 3450,2240,1610,1510,1250,1030, 825,625cm
_{^{-1 1 H NMR (CDCl 3)}} δ 0.86 (t, J = 6.8Hz, 3H), 1.18~1.48
(M, 10H), 1.50 (broad s, 1H), 1.96 (ddd, J = 13.8, 9.
9,3.2Hz, 1H), 2.08 (ddd, J = 13.8,9.7,5.3Hz, 1H), 3.39
(M, 1H), 3.81 (s, 3H), 4.01 (dd, J = 9.9,5.3Hz, 1H),
6.90 (d, J = 8.7Hz, 2H), 7.26 (d, J = 8.7Hz, 2H) MS m / z: 275 (M +, 4.0), 159 (100) Elementary analysis: as C ₁₇ H ₂₅ NO ₂ Calculated: C, 74.14; H, 9.15; N, 5.09% Found: C, 73.80; H, 9.24; N, 4.92% Reference Example 2 (2S, 4R) -4-tosyloxy-2- (4-methoxyphenyl) ) Synthesis of decannitrile (2S, 4R) -4-hydroxy-2- (4-methoxyphenyl) decanenitrile 559 mg (2.0 mmol) of pyridine 5m
1 ml of a solution of 774 mg 4.1 mmol of tosyl chloride under ice cooling in 3 ml of pyridine and 24 ml of dimethylaminopyridine (DMAP)
g (0.2 mmol) was added and the mixture was stirred at room temperature for 3 days. The reaction solution was adjusted to pH 7 with dilute hydrochloric acid, extracted with ether (150 ml), washed with dilute hydrochloric acid and saturated saline, and concentrated. The residue was subjected to column chromatography (Kieselgel 60, hexane: ethyl acetate =
4: 1) and purified (2S, 4R) -4-tosyloxy-2-
550 mg of (4-methoxyphenyl) decanenitrile (yield 6
3%).

 The identification data is shown below.

Oil ▲ [α] ²⁰ _D ▼ + 14 ゜ (c = 1.1, MeOH) IR (neat) 2940,2860,2240,1650,1600,1510,1460,1360,
1250,1170,1130,895 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.85 (t, J = 7.0 Hz, 3H), 1.19 (m, 8
H), 1.64 (m, 2H), 2.07 (m, 2H), 2.46 (s, 3H), 3.70
(M, 1H), 3.80 (s, 3H), 4.72 (m, 1H), 6.88 (d, J = 8.7H
z, 2H), 7.18 (d, J = 8.7Hz, 2H), 7.37 (d, J = 8.3Hz, 2
H), 7.85 (d, J = 8.3 Hz, 2H). MS m / z: 429 (M ⁺ , 0.8), 258 (56.2), 257 (100). Elemental analysis: As C ₂₄ H ₃₁ NO ₄ S Calculated: C, 67.10; H, 7.27; N, 3.26; S, 7.46 Found: C, 67.17; H, 7.43; N, 3.14; S, 7.52 Reference Example 3 Synthesis of (2R, 4R) -4-tosyloxy-2- (4-methoxyphenyl) decanenitrile 730 mg of (2R, 4R) -4-hydroxy-2- (4-methoxyphenyl) decanenitrile in the same manner as in Reference Example 2.
(2R, 4R) -4-tosyloxy-2-
563 mg of (4-methoxyphenyl) decanenitrile (yield 5
0%).

Oil ▲ [α] ²⁰ _D ▼ + 5.7 ゜ (c = 1.1, CHCl ₃ ) IR (neat) 2930,2870,2240,1610,1600,1360,1250,890cm
_{^{-1 1 H NMR (CDCl 3)}} δ 0.83 (t, J = 7.0Hz, 3H), 1.05-1.22
(M, 8H), 1.54-1.60 (m, 2H), 2.10 (ddd, J = 14.6,8.6,
4.1Hz, 1H), 2.36 (ddd, J = 14.6, 7.5, 6.2Hz, 1H), 2.46
(S, 3H), 3.82 (s, 3H), 3.87 (dd, J = 8.6,6.2Hz, 1H),
4.49 (dtd, J = 7.5,6.0,4.1Hz, 1H), 6.90 (d, J = 8.8Hz, 2
H), 7.23 (d, J = 8.8Hz, 2H), 7.35 (d, J = 8.3Hz, 2H), 7.
79 (d, J = 8.3 Hz, 2H). MS m / z: 429 (M ⁺ , 1), 258 (45), 257 (100), 231 (15),
159 (68). Elemental analysis: As C ₂₄ H ₃₁ NO ₄ S Calculated: C, 67.10; H, 7.27; N, 3.26; S, 7.46 Found: C, 66.90; H, 7.33; N, 3.19; S, 7.60. 1 (Production of compound of general formula (IV)) Synthesis of (S) -2- (4-methoxyphenyl) decanenitrile 0.10 g of sodium borohydride was added to a solution of 380 mg (0.885 mmol) of (2S, 4R) -4-tosyloxy-2 (4-methoxyphenyl) decanenitrile in 4 ml of dimethyl sulfoxide.
(2.65 mmol), and the mixture was heated and stirred at 70 ° for 2.5 hours. The reaction solution was neutralized with 4N hydrochloric acid, extracted with 100 ml of ethyl acetate, washed with brine, dried over anhydrous magnesium sulfate and concentrated. The residue was subjected to column chromatography (Kieselgel 6
0, hexane: ethyl acetate = 4: 1)
60 mg of an approximately 1: 1 mixture of (S) -2- (4-methoxyphenyl) decanenitrile and 1-cyano-2-hexyl-1- (4-methoxyphenyl) cyclopropane was obtained.

 The identification data is shown below.

Oil IR (neat) 2930,2860,2130,1610,1510,1460,1300,1250,
_{^{1180,1030,830cm -1 1 H NMR (CDCl 3}} ) δ 0.87 (t, J = 7.1Hz, 3H), 0.89 (t, J
= 6.9Hz, 3H), 117-1.94 (m, 27H), 3.71 (s, 3H), 3.81
(S, 3H), 6.86 (d, J = 8.9Hz, 2H), 6.89 (d, J = 8.8Hz, 2
H), 7.2 (d, J = 8.9 Hz, 2H), 7.23 (d, J = 8.8 Hz, 2H). MS m / z: 259 (M ⁺ , 7), 257 (M ⁺ , 9), 172 (11), 160 (1
2), 159 (100), 147 (16), 146 (35). Example 2 (Production of compound of general formula (II)) (S) -2- (4-Hydroxyphenyl) decanenitrile synthesis (S) -2- obtained in Example 1 was added to a solution of 814 mg (6.11 mmol) of aluminum chloride in 10 ml of dimethylsulfide.
A solution of 264 mg of a mixture of about 1: 1 (4-methoxyphenyl) decanenitrile and 1-cyano-2-hexyl-1- (4-methoxyphenyl) cyclopropane in 10 ml of dimethylsulfide was added, and the mixture was stirred at room temperature for 3 hours. Further, a mixed solution of 1 ml of ethanethiol and 5 ml of dichloromethane was added, and the mixture was stirred overnight. The mixture was neutralized by adding saturated sodium hydrogen carbonate, extracted with 250 ml of dichloromethane, washed with saturated saline, dried over anhydrous magnesium sulfate, and concentrated. The residue was separated by preparative thin-layer chromatography (hexane: ethyl acetate = 3: 1), and further separated by high performance liquid chromatography (Tosoh, Silica-60, 21.5 mm, ID × 300 mm, hexane: ethyl acetate = 100: 1) to give (S) -2- (4-hydroxyphenyl) decanenitrile (50 mg, yield 28%).

 The identification data is shown below.

Colorless crystals, melting point 41-42 ゜ ▲ [α] ²⁰ _D ▼ -8.6 ゜ (c = 2.5, MeOH) IR (neat) 3400, 2940, 2870, 2250, 1615, 1600, 1560, 1440,
_{^{830cm -1 1 H NMR (CDCl 3}} ) δ 2.87 (t, J = 6.7Hz, 3H), 1.20-1.36
(M, 10H), 1.36-1.52 (m, 2H), 1.76-1.94 (m, 2H), 3.
70 (dd, J = 8.4,6.4Hz.1H), 5.60-5.78 (broad s, 1H),
6.83 (d, J = 8.5 Hz, 2H), 7.16 (d, J = 8.5 Hz, 2H). High resolution MS: M ₁₇ calculated as C ₁₇ H ₂₅ ON M ⁺ calculated: 245.1774 Found: 245.176 Example 3 Synthesis of compound of general formula (I) Optically active (S) -2- (4) obtained in Example 2 37 mg of 4-hydroxyphenyl) decanenitrile and 4- (4-
Octyloxyphenyl) benzoic acid chloride (59 mg) was dissolved in dichloromethane (8 mg), and pyridine (0.5 ml) was added thereto.
Stirred under reflux for 10 hours. 50 ml of ether was added, and the mixture was washed with 10% hydrochloric acid, then with water until the aqueous layer became neutral, and further washed with saturated saline. After dehydration with anhydrous sodium sulfate, the solvent was distilled off to obtain 67 mg of a crude product. Purified by silica gel column chromatography (solvent: hexane / ethyl acetate mixed system) to obtain optically active 4- (1-cyanodecyl) (S) -4- (S-octyloxyphenyl) benzoate.
10 mg of phenyl were obtained. Measurement of the phase transition temperature was further recrystallized from ethanol, melting point is 92.5 ° C., the Sc ^* phase to 110 ° C., showed S _A phase to 140 ° C..

 The identification data is shown below.

_{NMR (CDCl 3): 0.86-0.92 (} m, 6H), 1.25-1.57 (m, 22
H), 1.78-1.91 (m, 4H), 3.78-3.84 (m, 1H), 4.02 (t,
J = 6.5Hz.2H), 7.01 (d, J = 8Hz, 2H), 7.26 (d, J = 8Hz, 2
H), 7.40 (d, J = 8 Hz, 2H), 7.60 (d, J = 8 Hz, 2H), 7.69
(D, J = 8 Hz, 2H), 8.22 (d, J = 8 Hz, 2H). IR: (Nujol): 1735,1605,1290,1280,1200,1175,1080,83
0,770 (cm ^-1 ) Example 4 Preparation of Sc ^* Liquid Crystal Composition and Display Element A base liquid crystal having the following composition and exhibiting a Sc phase was prepared.

The phase transition temperature (° C.) of this composition is as follows.

(N represents a nematic phase.) Sc comprising 90% of the parent liquid crystal and 10% of the compound of Example 3.
^{* When a} liquid crystal composition was prepared, it was found to be Sc ^* phase, 81
° C. S _A phase at below 86 ° C. indicates N ^* phase below its melting point was not clear.

The composition is heated to an isotropic liquid phase, which has a thickness of 2.
Two 3μm transparent electrode plates (polyimide coating-
(A rubbing orientation treatment was performed) to form a thin film cell, which was gradually cooled to room temperature to obtain a uniformly oriented Sc ^* phase cell.

A rectangular wave having an electrolytic strength of V _PP / μm, 50 Hz was applied to this cell, and its electro-optical response was measured.
A high-speed response of μs was confirmed. The tilt angle at this time is
The temperature was 18.2 ° C, and the contrast was good. The spontaneous polarization was 5.3 nC / cm ² and its polarity was

Then, it was prepared the mother liquid crystal 95% and compounds consisting of 5% Sc ^* composition of Example 3, the Sc ^* phase at 63 ° C. or less, S _A phase at 77.5 ° or less, at 84 ° C. or less N ^* Phase. The optical response at 25 ° C. similarly measured was 220 μs, the tilt angle at this time was 22.2 °, and the spontaneous polarization was 2.6 nC /
It was cm ^2. The contrast was very good.

〔The invention's effect〕

The optically active compound represented by the general formula (I) of the present invention exhibits a liquid crystal phase, and can induce a large spontaneous polarization by being used as a so-called chiral dopant in another Sc ^* liquid crystal composition or a Sc liquid crystal composition. And a high-speed response can be made possible. In addition, the general formula (I) of the present invention
The optically active compound represented by and the intermediate thereof can be easily produced industrially, are colorless, have excellent chemical stability against water, light, heat and the like, and are practical.

Further, the liquid crystal material comprising a chiral smectic liquid crystal compound or composition according to the present invention can realize a high-speed response of about 120 μsec, and is extremely useful as an optical switching element for display.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C07D 237/08 C07D 237/08 237/24 237/24 239/26 239/26 239/28 239/28 241/12 241/12 241/24 241/24 319/06 319/06 C09K 19/20 C09K 19/20 19/30 19/30 19/34 19/34 G02F 1/13 500 G02F 1/13 500 // C07M 7:00 (72 Inventor Tajiro Hiyama 4-29-3-101 Kamitsuruma, Sagamihara City, Kanagawa Prefecture 1380 CI Heights K-702 (58) Fields surveyed (Int. Cl. ⁶ , DB name) CA (STN) CAOLD (STN) REGISTRY (STN) WPIDS (STN)

Claims (5)

(57) [Claims] 1. An optically active compound having a cyano group and represented by the following general formula (I). (Wherein, R ¹ represents an alkyl group having 1 to 18 carbon atoms or an alkoxyl group, R ² represents an alkyl group having 1 to 18 carbon atoms, m represents 0 or 1, Are independently (Trans 1,4-cyclohexylene group), X represents a fluorine atom or a chlorine atom, and Z represents-
COO -, - OCO -, - CH 2 O -, - OCH 2 -, - CH 2 CH 2 -, -
Y represents COO or CH ₂ O, and C ^* represents an asymmetric carbon atom in the (R) or (S) configuration. ) 2. The optically active compound represented by the general formula (I) according to claim 1, wherein Y is COO. 3. A liquid crystal composition comprising at least one optically active compound represented by the general formula (I) according to claim 1. 4. A liquid crystal display device comprising the liquid crystal composition according to claim 3. 5. The method according to claim 1, which is represented by the following general formula (I ').
Or an optically active compound which is an intermediate of the compound of the general formula (I) according to 2. (In the formula, R ² and C ^* represent the same as those in the general formula (I) according to claim 1, and R ³ represents —OH or —OCH _3. )