JPH05271213A - Optically active 2,5-disubstituted tetrahydrofuran derivative and liquid crystal composition containing the same and liquid crystal element - Google Patents

Abstract

PURPOSE:To provide the subject derivative permitting the induction of a sufficient spontaneous polarization, the operation of the liquid crystal composition in a wide temperature range, low viscosity and high speed response by adding the derivative as a chiral dopant to other matrix liquid crystals. CONSTITUTION:An optically active 2,5-disubstituted tetrahydrofuran derivative of formula I [R<1> is alkyl (capable of being substituted with a halogen or alkoxy); X is single bond, O; the ring A is 1,4-phenylene, trans-1,4-cyclohexylene (capable of being substituted with F); the ring B is 1,4-phenylene (capable being substituted with F); R<2> is alkyl; the asymmetric carbon atoms at the 2 and 5-positions of the tetrahydrofuran ring are independently arranged in the (R) or (S) configuration], e.g. (2R, 5R) and (2S, 5R)-2-[4-(4-octyloxyphenyl)phenyl]-5- hexyltetrahydrofuran. The compound of formula I is obtained by reacting an optically active lactol of formula II with an organic metal compound of formula III (Y is MgBr, MgCl, etc.), dehydration-cyclizing the reaction product and subsequently separating the diastereomers.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a novel optically active
The present invention relates to a 5-disubstituted tetrahydrofuran derivative and a liquid crystal material containing the same, and more particularly to a ferroelectric liquid crystal display material excellent in high-speed 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, the TN type, which is the most common display method among them, has a very slow response as compared with other light emitting display methods such as CRT, and obtains a display memory (memory effect) when the applied electric field is cut off. Therefore, there are many restrictions on application to moving screens such as an optical shutter that requires a high-speed response, a printer head, or a television that requires time-division driving, and it cannot be said that it is a suitable display method.

Recently, a display method using a ferroelectric liquid crystal has been reported, and according to this, a TN type liquid crystal display of 100-1 is used.
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 the tilt type chiral smectic 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 the following conditions for use as a ferroelectric liquid crystal element, ie, (a) exhibiting the SC ^* phase in a wide temperature range including room temperature,
(B) To have an appropriate phase series on the high temperature side of the SC ^* phase in order to obtain good orientation, and have a large helical pitch.
(C) Having an appropriate tilt angle, (d) Small viscosity, (e) Large spontaneous polarization to some extent, (f)
No compound is known to satisfy the requirement of exhibiting a fast response alone. 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 a matrix liquid crystal showing a smectic C (hereinafter abbreviated as SC) phase (hereinafter abbreviated as SC host liquid crystal) and an optically active compound. The method of adding a dopant as a so-called chiral dopant is the most general method because a composition having a lower viscosity can be obtained and a high-speed response is possible.

The compound used as the chiral dopant does not necessarily have to exhibit the SC ^* phase or even the liquid crystal phase by itself, but a small amount of the compound can induce sufficient spontaneous polarization in the liquid crystal composition, and the chiral dopant. It is necessary to exhibit properties such as a sufficiently large pitch of the helix induced as a dopant.

In order to induce a 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. This is already known. Based on such an idea, the inventors of the present invention formula (IV)

[0008]

[Chemical 4]

(In the formula, Mes represents a liquid crystal skeleton, and R represents an alkyl group.) An optically active lactone derivative represented by the formula is synthesized. It has been found that a responsive SC ^* liquid crystal composition can be prepared. (Page 16 of the 16th Liquid Crystal Conference, and JP-A-2-286673.
Issue)

[0010]

However, in the compound of the general formula (IV), although the carbonyl group of the lactone ring gives a large dipole moment,
At the same time, there was a problem that the viscosity of the compound was made very large.

It is generally known that the response time of a ferroelectric liquid crystal is proportional to its viscosity and inversely proportional to its spontaneous polarization. For this reason, when a compound of general formula (IV) is used as a chiral dopant, a fast response is obtained. However, the spontaneous polarization at that time becomes a very large value. However, when a liquid crystal element is actually manufactured, if the SC ^* liquid crystal composition has too large spontaneous polarization, it adversely affects the memory property and the like, and it is often difficult to operate properly.
Therefore, in reality, the spontaneous polarization of the composition cannot be increased so much.

Therefore, as a chiral dopant, an optically active compound that can induce a sufficient spontaneous polarization by adding a small amount to a host liquid crystal and can achieve a high-speed response without increasing the viscosity of the composition is desired. ing.

The problem to be solved by the present invention is to provide such an optically active compound and to provide a ferroelectric liquid crystal display material using the same.

[0014]

In order to solve the above-mentioned problems, the present invention has the general formula (I)

[0015]

[Chemical 5]

(In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms which may be substituted by a fluorine atom or an alkoxyl group having 1 to 10 carbon atoms, preferably 6 to 10 carbon atoms. Represents a straight-chain alkyl group, X represents a single bond or -O-, and ring A is optionally substituted with 1 or 2 fluorine atoms 1,4
Represents a phenylene group or a trans-1,4-cyclohexylene group, preferably a 1,4-phenylene group, and ring B is 1,4-which may be substituted with one or two fluorine atoms. It represents a phenylene group, preferably a 1,4-phenylene group, and R ² represents a linear or branched alkyl group having 1 to 18 carbon atoms, and preferably a straight chain having 1 to 8 carbon atoms. It represents a chain alkyl group, and the asymmetric carbon atoms at the 2- and 5-positions of the tetrahydrofuran ring are each independently in the (R) or (S) configuration. ), Which is an optically active 2,5-disubstituted tetrahydrofuran derivative.

The present invention also provides a method for producing these optically active tetrahydrofuran derivatives represented by the general formula (I).

The compounds of general formula (I) according to the present invention are
For example, it can be manufactured according to the following manufacturing method.

That is, the general formula (II)

[0020]

[Chemical 6]

(In the formula, R ² represents a linear or branched alkyl group having 1 to 18 carbon atoms, and the asymmetric carbon atom at the 5-position of the tetrahydrofuran ring has an (R) or (S) configuration. An optically active lactol derivative represented by the general formula (III)

[0022]

[Chemical 7]

(Wherein R ¹ , X, ring A and ring B have the same meanings as in formula (I), Y represents MgBr,
Represents MgCl, MgI or Li. ) Is reacted with an organometallic compound represented by the general formula (V)

[0024]

[Chemical 8]

(In the formula, R ¹ , X, ring A, ring B and R ² have the above-mentioned meanings, and the asymmetric carbon atom at the 4-position of the 1,4-dihydroxyalkyl group is (R) or (S It is possible to obtain a 1,4-diol derivative represented by (1) configuration. This is a mixture of diastereomers. Next, by subjecting this to cyclodehydration in the presence of an acid catalyst,
A tetrahydrofuran derivative is obtained which is a mixture of diastereomers. Each diastereomer can be easily separated by a conventional separation means to obtain the compound of general formula (I).

Here, the optically active lactol derivative of the general formula (II) was first developed by the present inventors, and is disclosed in Japanese Patent Application No. 3-22.
The compound reported in Japanese Patent Publication No. 7507 can be produced, for example, as follows.

That is, the general formula (VI)

[0028]

[Chemical 9]

(Wherein R ² has the same meaning as in formula (I)) and the optically active oxirane derivative represented by formula (VII) is reacted with the dianion of acetic acid.

[0030]

[Chemical 10]

(In the formula, R ² has the same meaning as in formula (I), and the asymmetric carbon atom at the 5-position of the lactone ring is
(R) or (S) arrangement. An optically active lactone derivative represented by the formula (1) is obtained.

By reducing this optically active lactone derivative with diisopropylaluminum hydride, an optically active lactol derivative of the general formula (II) can be obtained.

Further, the organometallic compound of the general formula (III) can be easily obtained from the corresponding chloride, bromide or iodide.

As described above, the optically active 2,5-di-substituted tetrahydrofuran derivative of the general formula (I) of the present invention can be obtained, and each specific compound belonging to these derivatives has a phase such as a melting point. Transition temperature, elemental analysis, infrared absorption spectrum (IR), nuclear magnetic resonance spectrum (NMR),
It can be confirmed by means such as mass spectrum (MS).

The representative examples of the compounds of the general formula (I) thus obtained, and the optical rotation at 20 ° C. and the phase transition temperature measured using the sodium D line are shown below.

[0036]

[Chemical 11]

(In the above, Cr represents a crystalline phase, I represents an isotropic liquid phase, C2 in the absolute configuration of the tetrahydrofuran ring represents a carbon atom at the 2-position, and C5 represents a carbon atom at the 5-position. ) The present invention also provides a liquid crystal composition using the optically active tetrahydrofuran derivative represented by the general formula (I).

The liquid crystal composition of the present invention has the above general formula (I).
It contains at least one of the above compounds as a constituent. Particularly for ferroelectric liquid crystal displays, 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. The composition is suitable.

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

One of the excellent features of the compound of the general formula (I) of the present invention is that when it is used as a chiral dopant for a ferroelectric liquid crystal, it has the above-mentioned optically active lactone derivative of the general formula (IV). It can be mentioned that it can induce a considerably large spontaneous polarization, though it does not reach the limit.

For example, as shown in the embodiments described later,
The above No. 10% by weight of compound 1 and SC host liquid crystal 9
In the SC ^* liquid crystal composition consisting of 0% by weight, the value of spontaneous polarization at 25 ° C. is +6.94 nC / cm ² , which is the most commonly used asymmetric source in liquid crystal (S) -2-methyl. SC ^* liquid crystal compound derived from butanol, for example 4-decyloxybenzoic acid 4-[(S) -2
The spontaneous polarization of -methylbutoxy] phenyl is +1 to 2 nC / c when measured alone without addition to the host liquid crystal.
It can be seen that it is considerably larger than that of about m ² . Therefore, if it is contained in the non-chiral matrix liquid crystal in an amount of about 4 to 5% by weight, it becomes possible to induce spontaneous polarization to an extent sufficient for high-speed response.

Further, the compound of the general formula (I) has a small viscosity as compared with, for example, an optically active lactone derivative of the general formula (IV), since it has no carbonyl group. Therefore, in the SC ^* liquid crystal composition containing the compound of the general formula (I), a high-speed response is possible for the magnitude of the spontaneous polarization.

The compound of the general formula (I) does not show not only the SC ^* phase but also the liquid crystal phase by itself, but the addition of a small amount does not narrow the temperature range of the SC ^* phase and other liquid crystal phases so much. It is easy to obtain a ferroelectric liquid crystal composition exhibiting the SC ^* phase in a wide temperature range.

The SC compound used in the host liquid crystal to be added with the compound of the general formula (I) of the present invention as a dopant is, for example, the following general formula (A).

[0045]

[Chemical 12]

(In the formula, R ^a and R ^b represent a linear or branched alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkanoyloxy group or an alkoxycarbonyloxy group, which may be the same or different. A phenylbenzoate compound represented by the general formula (B)

[0047]

[Chemical 13]

Examples thereof include phenylpyrimidine compounds represented by the formula (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) is also included.

[0050]

[Chemical 14]

(In the formula, R ^a and R ^b have the same meanings as in formula (A), and ring L and ring M are 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 halogens thereof Represents a substituent, and may be the same or different, and Z ^a is —COO—, —OCO—, or —C.
_{H 2 O -, - OCH 2} -, - CH 2 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 of the SC phase to a high temperature range, the general formula (D)

[0053]

[Chemical 15]

(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). Represent
They may be the same or different, and Z ^a and Z ^b each have the same meaning as Z ^{a in} formula (C), and may be the same or different. A tricyclic compound represented by the formula (1) can be used.

It is effective that these compounds are mixed and used as an SC liquid crystal composition, but it is only necessary to show the SC phase as the composition, and it is not always 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 compound to the thus obtained SC liquid crystal composition as a chiral dopant, the compound can be easily added in a wide temperature range including room temperature. A liquid crystal composition exhibiting the SC ^* phase can be obtained.

The present invention also provides a liquid crystal display device comprising a liquid crystal composition containing the optically active 2,5-disubstituted tetrahydrofuran derivative represented by the general formula (I).

Examples of the liquid crystal display element of the present invention include:
The SC ^* liquid crystal composition obtained by adding the compound of the general formula (I) to the above SC host liquid crystal is sealed as a thin film of about 1 to 20 μm between two transparent glass electrodes,
It can be used as a display cell.

In order to obtain good contrast, it is necessary to make the monodomain uniformly oriented. For this reason, many methods have been tried, but in order to show a good alignment property, as a liquid crystal material, from the high temperature side, I phase-N ^* (chiral nematic) phase-SA (smectic A) phase-SC ^* phase It is said that it is necessary to increase the helical pitch in the N ^* phase and the SC ^* phase. In order to increase the helical pitch, a method of mixing an appropriate amount of chiral compounds having mutually opposite twist directions is generally used, but the helical pitch induced by the compound of the general formula (I) of the present invention is not so small. So the adjustment is easy.

[0060]

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

The structures of the compounds are elemental analysis, NMR,
Confirmed by IR and MS. The phase transition temperature was measured by using a polarization microscope equipped with a temperature control stage and a differential scanning calorimeter (DSC) together. (KB in IR
r) is by tableting, (neat) is by liquid film. CDCl _{3 in} NMR represents a solvent,
s is a singlet, d is a doublet, t is a triplet, q is a quadruplet, m
Represents a multiple line and, for example, dd represents a double double line. J represents a coupling constant. 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%".

Reference Example 1 (5R) -5-hexyl-
Synthesis of 2-hydroxytetrahydrofuran (compound of general formula (II))

(1-i) Synthesis of (R) -4-decanolide

[0064]

[Chemical 16]

15.4 ml of diisopropylamine (11
0 mmol) of tetrahydrofuran (THF) 100 m
To the 1 solution, 71.0 ml (110 mmol) of 1.5 M butyllithium-hexane solution was added at -78 ° C, and the mixture was stirred for 30 minutes. Acetic acid 3.0 g (50 mmol) in THF 50 m
1 solution was added and stirred for 1 hour, and 6.4 g (50.0 mmol) of (R) -1,2-epoxyoctane in THF 50 m was added.
1 solution was added and the temperature was raised to room temperature. Add 1M of 3M hydrochloric acid
The mixture was extracted with 100 ml of ethyl acetate three times, the extract was concentrated, 200 ml of toluene and 50 mg of p-toluenesulfonic acid were added to the residue, and the mixture was heated under reflux for 2 hours. The reaction solution was concentrated and then distilled under reduced pressure to obtain (R) -4-decanolide 1.2.
3 g (14% yield) was obtained. Colorless oil, boiling point 160 ° C / 0.2mmHg

(1-ii) (5R) -5-hexyl-
Synthesis of 2-hydroxytetrahydrofuran

[0067]

[Chemical 17]

575 mg of (R) -4-decanolide (3.
4 mmol) in 5 ml of dichloromethane at -78 ° C.
Then, 1.0 ml of a diisobutylaluminum hydride-toluene solution (4.1 ml, 4.0 mmol) was added and the mixture was stirred for 2 hours. After adding 5 ml of 3M hydrochloric acid and filtering through Celite, the mixture was extracted 3 times with 50 ml of ethyl acetate, and the extract was subjected to column chromatography (silica gel, toluene / ether = 5 /
Separation and purification using (1), (5R) -5-hexyl-
2-hydroxytetrahydrofuran 525 mg (yield 9
0%). Colorless oily substance

(Example 1) (2R, 5R) and (2R
S, 5R) -2- [4- (4-octyloxyphenyl) phenyl] -5-hexyltetrahydrofuran (N
o. 1 and No. Compound 2)

(1-a) (4R) -1- [4- (4-
Octyloxyphenyl) phenyl] decane-1,4-
Diol synthesis

[0071]

[Chemical 18]

A Grignard reagent prepared from 722 mg (2.0 mmol) of 1-bromo-4- (4-octyloxyphenyl) benzene and 73 mg (3.0 mmol) of magnesium was obtained at room temperature in a reference example (5R). −
5-hexyl-2-hydroxytetrahydrofuran 86
mg (0.50 mmol) of tetrahydrofuran 2 ml
Reacted with solution. Saturated ammonium chloride aqueous solution 10m
1 was added, and the mixture was extracted 3 times with 50 ml of ethyl acetate. The organic layer was washed, concentrated, and then separated and purified using silica gel column chromatography (hexane / ethyl acetate = 2/1) to obtain (4R) -1- [4- (4-octyloxyphenyl). 148 mg of phenyl] decane-1,4-diol was obtained (yield 65%). IR (KBr) 3300, 2940, 2870, 16
10, 1500, 1470, 1255, 1050, 10
_{^{00,820cm -1 1 H NMR (CDCl 3}} ) δ 0.88 (t, J =
7.0Hz, 3H), 0.89 (t, J = 6.8Hz,
3H), 1.23 to 1.72 (m, 20H), 1.76.
-1.83 (m, 2H), 1.87-1.97 (m, 2)
H), 3.62 to 3.70 (m, 1H), 3.99.
(T, J = 6, 6 Hz, 2H), 4.72 to 4.78
(M, 1H), 6.97 (d, J = 8.8Hz, 2
H), 7.39 (dd, J = 8.1 and 1.6 Hz,
2H), 7.50 (d, J = 8.8Hz, 2H), 7.
53 (d, J = 8.5 Hz, 2H) MS m / z 549 (M ⁺ , 0.5), 454 (1
9), 437 (23), 436 (68), 351 (1
2), 324 (29), 311 (100)

(1-b) (2R, 5R) and (2
Synthesis of S, 5R) -2- [4- (4-octyloxyphenyl) phenyl] -5-hexyltetrahydrofuran

[0074]

[Chemical 19]

(4R) -1- obtained in (1-a) above
[4- (4-octyloxyphenyl) phenyl] decane-1,4-diol 150 mg (0.33 mmol)
In 40 ml of toluene solution of p-toluenesulfonic acid 5
mg was added and the mixture was heated at 120 ° C. for 10 minutes. After the reaction solution was concentrated, it was separated using silica gel column chromatography (hexane / ethyl acetate = 20/1), and further preparative high performance liquid chromatography (Tosoh, Silic).
a-60, 21.5 mm ID x 300 mm, hexane /
Separation and purification using ethyl acetate = 40/1), (2
R, 5R) -2- [4- (4-octyloxyphenyl) phenyl] -5-hexyltetrahydrofuran (polar component, cis isomer) 80 mg (55% yield) and (2
63 mg (yield 44%) of S, 5R) -2- [4- (4-octyloxyphenyl) phenyl] -5-hexyltetrahydrofuran (nonpolar component, trans isomer) were obtained.

(2R, 5R) -2- [4- (4-octyloxyphenyl) phenyl] -5-hexyltetrahydrofuran colorless plate crystal melting point 96.3 ° C. [α] _D ²⁰ + 24.9 ° (c = 0) .89, CHCl ₃ ) IR (KBr) 2970, 2940, 2860, 16
05, 1500, 1470, 1250, 1070, 82
_{^{0,815cm -1 1 H NMR (CDCl 3}} ) δ 0.90 (t, J =
7.0Hz, 3H), 0.90 (t, J = 7.1Hz,
3H), 1.25 to 1.56 (m, 18H), 1.55
~ 1.69 (m, 2H), 1.72-1.88 (m, 4)
H), 2.07 (ddt, J = 12.0, 8.3, an
d6.4 Hz, 1H), 2.26 to 2.34 (m, 1
H), 3.99 (t, J = 6.6 Hz, 2H), 3.9
6 to 4.05 (m, 1H), 4.90 (t, J = 7.3)
Hz, 1H), 6.95 (d, J = 8.8Hz, 2
H), 7.39 (d, J = 8.3 Hz, 2H), 7.4
9 (d, J = 8.8 Hz, 2H), 7.50 (d, J =
8.3 Hz, 2H) MS m / z 436 (M ⁺ , 100), 351 (1
1), 239 (12), 198 (26), 197 (1
3), 196 (16), 183 (10) Elemental analysis: C ₃₀ H ₄₄ O ₂ Calculated: C, 82.52; H, 10.16 % Found: C, 82.67; H, 10 . 40%

(2S, 5R) -2- [4- (4-octyloxyphenyl) phenyl] -5-hexyltetrahydrofuran colorless plate crystal, melting point 106.2-106.8 ° C. [α] _D ²⁰ -43.1 (C = 0.78, CHCl ₃ ) IR (KBr) 2980, 2940, 2870, 16
10, 1500, 1475, 1250, 1060, 82
_{^{0,810cm -1 1 H NMR (CDCl 3}} ) δ 0.89 (t, J =
6.6 Hz, 6 H), 1.25 to 1.56 (m, 19
H), 1.60 to 1.74 (m, 2H), 1.78 to
1.83 (m, 2H), 1.89 (ddt, J = 12.
3, 9.8, and 7.8Hz, 1H), 2.10
2.18 (m, 1H), 2.34 to 2.41 (m, 1
H), 3.99 (t, J = 6.6 Hz, 2H), 4.1
9 (dq, J = 4.19 Hz, 1H), 5.02 (d
d, J = 7.9 and 6.6 Hz, 1H), 6.95
(D, J = 8.8 Hz, 2H), 7.37 (d, J =
8.2H), 7.49 (d, J = 8.8Hz, 2H),
7.5 (d, J = 8.2 Hz, 2H) MS m / z 436 (M ⁺ , 100), 351 (1
3), 239 (13), 198 (23), 197 (1
4), 196 (19), 183 (11), 170 (1
9) Elemental analysis: C ₃₀ H ₄₄ O ₂ Calculated: C, 82.52; H, 10.16 % Found: C, 82.52; H, 10.35 %

(Example 2) (2R, 5R) -2- [4
Synthesis of-(4-heptylphenyl) phenyl] -5-hexyltetrahydrofuran (Compound No. 3) In Example 1, instead of using 1-bromo-4- (4-octyloxyphenyl) benzene, 1-bromo-
In the same manner as in Example 1 except that 4- (4-heptylphenyl) benzene was used, (2R, 5R) -2- [4- (4
-Heptylphenyl) phenyl] -5-hexyltetrahydrofuran was obtained.

White crystal [α] _D ²⁰ + 26.6 ° (c = 1.12, CHCl ₃ ) IR (KBr) 2960, 2930, 2860, 15
00, 1465, 1385, 1260, 1065, 10
05,815,725cm ^-1

Example 3 Preparation of SC ^* Liquid Crystal Composition An SC host liquid crystal (H-1) having the following composition was prepared.

[0081]

[Chemical 20]

The phase transition temperature of this host liquid crystal was as follows. 12.5 ° C (Cr → SC), 55.5 ° C (SC-S
A), 64.5 ° C (SA-N), 70 ° C (NI) (in the above, for example, SC-SA is a smectic C phase-
It means that the smectic A phase transition temperature and the smectic A phase-smectic C phase transition temperature are the same temperature. The same applies below. )

90% of this SC matrix liquid crystal (H-1) and No. 1 of Example 1 were used. A SC ^* liquid crystal composition (M-1) consisting of 10% of the compound of 1 was prepared. The phase transition temperature was as follows. 52.5 ° C (SC ^* -SA), 58 ° C (SA-N ^* ), 6
The melting point at 3.5 ° C (N ^* -I) was not clear.

In the same manner as above, SC host liquid crystal (H-
1) 80% and No. SC consisting of 20% of compound 1
^{* A} liquid crystal composition (M-2) was prepared. The phase transition temperature was as follows. 49.5 ° C (SC ^* -SA), 51.5 ° C (SA-
N ^* ), 56 ° C. (N ^* -I) This composition crystallized when left at room temperature or below for a long time and had a melting point of about 35 ° C.

In the same manner as above, SC host liquid crystal (H-
1) 90% and No. SC consisting of 2% compound 2
^{* A} liquid crystal composition (M-3) was prepared. The phase transition temperature was as follows. 55.5 ° C (SC ^* -SA), 62.5 ° C (SA-
N ^* ), 67.5 ° C. (N ^* -I) This composition crystallized when left at room temperature or below for a long time, and its melting point was about 25 ° C.

In the same manner as above, SC host liquid crystal (H-
1) 80% and No. SC consisting of 20% of compound 2
^{* A} liquid crystal composition (M-4) was prepared. The phase transition temperature was as follows. 55 ° C (SC ^* -SA), 59.5 ° C (SA-N ^* ), 6
5 ° C (N ^* -I) This composition crystallized when left at room temperature or below for a long time, and its melting point was about 40 ° C.

Next, 90% of SC host liquid crystal (H-1) and No. 2 of Example 2 were used. SC ^* liquid crystal composition (M-5) consisting of 10% of the compound of Example 3 was prepared. The phase transition temperature was as follows. 44 ° C (SC ^* -SA), 52 ° C (SA-N ^* ), 60.
5 ° C (N ^* -I) Melting point was not clear.

Example 4 Preparation of Liquid Crystal Display Device The SC ^* liquid crystal composition (M-1) obtained in Example 3 was heated to the isotropic liquid (I) phase, and this was heated to 2 μm in thickness. A glass cell made of a transparent electrode plate (polyimide coating-aligned by rubbing) was filled to prepare a display element. When this was gradually cooled to room temperature, a uniformly aligned SC ^* phase liquid crystal display device was obtained.

Electric field strength of 10 V _pp / μm, 5
When a rectangular wave of 0 Hz was applied and the electro-optical response speed was measured, a high-speed response of 64 μsec at 25 ° C. was confirmed. At this time, the tilt angle was 22.6 °, and the contrast was good. This spontaneous polarization is +6.
It was 94 nC / cm ² .

Similarly, the SC ^* liquid crystal composition (M-
2), (M-3), (M-4) and (M-5) were used to prepare a liquid crystal display element, and its characteristics were measured. The results are shown below.

(M-2): Response 28 μsec, spontaneous polarization +1
1.7 nC / cm ² , tilt angle 21.1 °, good contrast (measurement at 35 ° C.) (M-3): response 126 μsec, spontaneous polarization −2.26 nC
/ Cm ² , tilt angle 18.4 °, good contrast (2
(Measurement at 6 ° C.) (M-4): Response 60 μsec, spontaneous polarization −3.72 nC /
cm ² , tilt angle 19.4 °, good contrast (40
(Measurement at C) (M-5): Response 96 μs, spontaneous polarization +3.93 nC /
cm ² , tilt angle 20.3 °, good contrast (25
(Measured in ° C)

[0092]

INDUSTRIAL APPLICABILITY The optically active compound represented by the general formula (I) of the present invention can induce a sufficient spontaneous polarization by adding a small amount as a so-called chiral dopant to another host liquid crystal, and has a wide temperature range. It is possible to provide a liquid crystal composition that is operable and does not increase the viscosity of the composition so much that a high-speed response is possible.

The compound of the general formula (I) of the present invention is very practical because it can be easily produced industrially, is colorless, and has excellent chemical stability to water and light. further,
The chiral smectic liquid crystal composition of the present invention has about 3
It is possible to realize a high-speed response of 0 μsec, which is extremely useful as a display optical switching element.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hijiro Hiujiro 4-29-3-101 Kamizuruma, Sagamihara City, Kanagawa Prefecture (72) Inventor Tetsuo Kusumoto 1-9-2-102, Minamidai, Sagamihara City, Kanagawa Prefecture (72) Inventor Kenichi Sato 35-11 Kamimizo, Sagamihara-shi, Kanagawa (72) Inventor Akiko Nakayama 1380-K-702, Yamazaki-cho, Machida-shi, Tokyo

Claims (6)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ is a halogen atom or 1 to 10 carbon atoms.
Represents an alkyl group having 1 to 18 carbon atoms which may be substituted by an alkoxyl group, X represents a single bond or -O-, and ring A is 1,4-phenylene optionally substituted by a fluorine atom. Group or trans-1,4
Represents a cyclohexylene group, ring B represents a 1,4-phenylene group optionally substituted by a fluorine atom, R ² represents an alkyl group having 1 to 18 carbon atoms,
The asymmetric carbon atoms at positions 2 and 5 of the tetrahydrofuran ring are each independently in the (R) or (S) configuration. ) An optically active 2,5-disubstituted tetrahydrofuran derivative represented by 2. The optically active 2,5-disubstituted tetrahydrofuran derivative according to claim 1, wherein both ring A and ring B are 1,4-phenylene groups. 3. A compound represented by the general formula (II): (In the formula, R ² represents an alkyl group having 1 to 18 carbon atoms, and the asymmetric carbon atom at the 5-position of the tetrahydrofuran ring is
(R) or (S) arrangement. ) And an optically active lactol derivative represented by the general formula (III): (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, and X represents a single bond or-
Represents O-, and ring A is a 1,4-phenylene group optionally substituted by a fluorine atom or trans-1,4-
Represents a cyclohexylene group, ring B represents a 1,4-phenylene group optionally substituted by a fluorine atom,
Y represents MgBr, MgCl, MgI or Li. ) By reacting with an organometallic compound represented by
The 1,4-diol derivative, which is dehydrated and cyclized in the presence of an acid catalyst, and the resulting diastereomer is then separated. The optics represented by the general formula (I) according to claim 1. Process for the preparation of active 2,5-disubstituted tetrahydrofuran derivatives. 4. A liquid crystal composition containing the optically active 2,5-disubstituted tetrahydrofuran derivative represented by the general formula (I) according to claim 1. 5. The liquid crystal composition according to claim 4, which exhibits a ferroelectric chiral smectic phase. 6. A liquid crystal display device using the liquid crystal composition according to claim 4.