JP2525224B2 - Liquid crystalline compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) The present invention relates to a novel liquid crystal compound and a liquid crystal composition containing the compound.

Liquid crystal substances and compositions thereof are used for various display devices by utilizing anisotropy of dielectric constant (abbreviated as Δε) and anisotropy of refractive index of light (abbreviated as Δn) in the liquid crystal phase. Have been.

For liquid crystal display system, electrolytic controlled birefringence type (ECB type), twisted nematic type (TN type), super twist birefringence type (SBE type), dynamic scattering type ( There are various methods such as DS type) and guest / host type.

A liquid crystal material used for a display device has a wide liquid crystal phase temperature range, low viscosity, a large positive Δε value or a negative Δε value depending on its display system and various characteristics required for a display element.
It must have various characteristics such as the value and various characteristics (especially threshold voltage) of the display element not changing greatly over a wide temperature range.

However, at present, the liquid crystal phase temperature range, operating voltage,
There is no single compound that can be practically used in terms of response performance. In practice, a mixture of several liquid crystal compounds or a mixture of several liquid crystal compounds with a compound having a potential liquid crystallinity or a non-liquid crystal substance is provided.

An object of the present invention is to provide a liquid crystal compound and a liquid crystal composition that can be used in a liquid crystal display device.
Here, the liquid crystal compound means, in addition to the compound exhibiting a liquid crystal phase, a compound which does not usually exhibit a liquid crystal phase but effectively acts on a certain surface of liquid crystal behavior when dissolved in another liquid crystal compound. .

During the first (the invention of structure) the present invention is (1) the general formula ^{R 1 -A 1 -B 1 -A 2} B 2 -A 3 n CH 2 m CH = CF 2 (I) ( wherein, R ¹ is Hydrogen or alkyl having 1 to 20 carbons or alkenyl having 2 to 20 carbons, and in these alkyl and alkenyl, one --CH ₂ --group or two non-adjacent --CH ₂ --groups is --O-- It may be substituted with a group, and the position and number of the double bond can be arbitrarily selected, wherein A ¹ , A ² and A ³ are each independently And this The hydrogen of may be replaced by fluorine, chlorine or methyl. In the formula, B ¹ and B ² are each independently --CH ₂ CH ₂ -,-
CH ₂ O—, —OCH ₂ — or a single bond, n is 0 or 1
Is an integer and m is a natural number of 1 to 20. The second aspect of the present invention is a liquid crystal composition comprising (2) at least one compound represented by the general formula (I).

Among the compounds of the present invention in which n = 0 in the above formula (I), preferred compounds include compounds represented by the following general formula.

In these formulas, R ¹ has the meaning described above, and R ² is
CH _{2 m} CH = CF ₂ (m is a natural number of 1 to 20), and the phenylene ring is Or May be substituted.

Among the compounds of the present invention having two 6-membered rings represented by the above formula, those in which R ¹ is linear alkyl or alkoxy having 1 to 12 carbon atoms are preferable. Moreover, the thing whose m in R < ² > is 1-10 is preferable.

Examples of the compound of the present invention represented by the formula (1) include 4 '-(3,3-difluoro-2-propenyl) biphenyl 4-methyl-4'-(3,3-difluoro-2-propenyl) biphenyl 4 -Ethyl-4 '-(3,3-difluoro-2-propenyl) biphenyl 4-propyl-4'-(3,3-difluoro-2-propenyl) biphenyl 4-butyl-4 '-(3,3-difluoro 2-Propenyl) biphenyl 4-pentyl-4 '-(3,3-difluoro-2-propenyl) biphenyl 4-hexyl-4'-(3,3-difluoro-2-propenyl) biphenyl 4-heptyl-4 ' -(3,3-Difluoro-2-propenyl) biphenyl 4-octyl-4 '-(3,3-difluoro-2-propenyl) biphenyl 4-nonyl-4'-(3,3-difluoro-2-propenyl) Bihue Nyl 4-decyl-4 '-(3,3-difluoro-2-propenyl) biphenyl 4-undecyl-4'-(3,3-difluoro-2-propenyl) biphenyl 4-dodecyl-4 '-(3,3 -Difluoro-2-propenyl) biphenyl 4 '-(4,4-difluoro-3-butenyl) biphenyl 4-methyl-4'-(4,4-difluoro-3-butenyl) biphenyl 4-ethyl-4 '-( 4,4-Difluoro-3-butenyl) biphenyl 4-propyl-4 '-(4,4-difluoro-3-butenyl) biphenyl 4-butyl-4'-(4,4-difluoro-3-butenyl) biphenyl 4 -Pentyl-4 '-(4,4-difluoro-3-butenyl) biphenyl-4-hexyl-4'-(4,4-difluoro-3-butenyl) biphenyl 4-heptyl-4 '-(4,4-difluoro -3-Buteni ) Biphenyl 4-octyl-4 '-(4,4-difluoro-3-butenyl) biphenyl 4-nonyl-4'-(4,4-difluoro-3-butenyl) biphenyl 4-decyl-4 '-(4, 4-difluoro-3-butenyl) biphenyl 4-undecyl-4 '-(4,4-difluoro-3-butenyl) biphenyl 4-dodecyl-4'-(4,4-difluoro-3-butenyl) biphenyl etc. . Examples of the compound represented by the formula (2) include 4- (3,3-difluoro-2-propenyl) phenylcyclohexane trans-4-methyl- [4- (3,3-difluoro-2.
-Propenyl) phenyl] cyclohexane trans-4-ethyl- [4- (3,3-difluoro-2
-Propenyl) phenyl] cyclohexane trans-4-propyl- [4- (3,3-difluoro-
2-Propenyl) phenyl] cyclohexane trans-4-butyl- [4- (3,3-difluoro-2
-Propenyl) phenyl] cyclohexane trans-4-pentyl- [4- (3,3-difluoro-
2-Propenyl) phenyl] cyclohexane trans-4-hexyl- [4- (3,3-difluoro-
2-Propenyl) phenyl] cyclohexane trans-4-heptyl- [4- (3,3-difluoro-
2-Propenyl) phenyl] cyclohexane trans-4-octyl- [4- (3,3-difluoro-
2-Propenyl) phenyl] cyclohexane trans-4-nonyl- [4- (3,3-difluoro-2)
-Propenyl) phenyl] cyclohexane trans-4-decyl- [4- (3,3-difluoro-2
-Propenyl) phenyl] cyclohexane trans-4-undecyl- [4- (3,3-difluoro-2-propenyl) phenyl] cyclohexane trans-4-dodecyl- [4- (3,3-difluoro-
2-Propenyl) phenyl] cyclohexane 4- (4,4-difluoro-3-butenyl) phenylcyclohexane trans-4-methyl- [4- (4,4-difluoro-3)
-Butenyl) phenyl] cyclohexane trans-4-ethyl- [4- (4,4-difluoro-3)
-Butenyl) phenyl] cyclohexane trans-4-propyl- [4- (4,4-difluoro-
3-butenyl) phenyl] cyclohexane trans-4-butyl- [4- (4,4-difluoro-3)
-Butenyl) phenyl] cyclohexane trans-4-pentyl- [4- (4,4-difluoro-
3-butenyl) phenyl] cyclohexane trans-4-hexyl- [4- (4,4-difluoro-
3-butenyl) phenyl] cyclohexane trans-4-heptyl- [4- (4,4-difluoro-
3-butenyl) phenyl] cyclohexane trans-4-octyl- [4- (4,4-difluoro-
3-butenyl) phenyl] cyclohexane trans-4-nonyl- [4- (4,4-difluoro-3)
-Butenyl) phenyl] cyclohexane trans-4-decyl- [4- (4,4-difluoro-3
-Butenyl) phenyl] cyclohexane trans-4-undecyl- [4- (4,4-difluoro-3-butenyl) phenyl] cyclohexane trans-4-dodecyl- [4- (4,4-difluoro-
Examples thereof include 3-butenyl) phenyl] cyclohexane. When the compound of the formula (3) is exemplified, 4- [trans-4- (3,3-difluoro-2-propenyl) cyclohexyl] cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-methylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-ethylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-propylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-butylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-pentylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-hexylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-heptylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-octylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-nonylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-decylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-undecylcyclohexyl) cyclohexane trans-1- (3,3-difluoro-2-propenyl)
-4- (trans-4-dodecylcyclohexyl) cyclohexane 4- [trans-4- (44-difluoro-3-butenyl) cyclohexyl] cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-methylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-ethylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-propylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-butylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-pentylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-hexylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-heptylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-octylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-nonylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-decylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-undecylcyclohexyl) cyclohexane trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-dodecylcyclohexyl) cyclohexane and the like.

Among the compounds of the present invention in which n = 1 in the above formula (I), preferred compounds include compounds represented by the following formula.

In these formulas, R ¹ and R ² have the above-mentioned meanings, and a phenylene ring is May be substituted. In these, m in R ² is 1 to 10
Are particularly preferred.

The compound of the present invention can be produced, for example, according to the following synthetic method.

(In the above formula, R ¹ , A ¹ , A ² , A ³ , B ¹ , B ² , n and m have the above-mentioned meanings, and Ph means phenyl.) That is, the general formula (II) The aldehyde derivative represented by is reacted with triphenylphosphine and sodium chlorodifluoroacetate under reflux in a solvent of diethylene glycol dimethyl ether. This reaction is a bititei (Wi
ttig) reaction is known as a reaction for generating a carbon-carbon double bond (for example, Org. Synth. col. Vol.
V, 390 (1973)). The 2,2-difluoroethene derivative of the formula (I) can be obtained by subjecting the reaction product to separation and purification operations such as distillation under reduced pressure, chromatography and recrystallization.

The aldehyde derivative represented by the general formula (II), which is a starting material, can be produced, for example, according to the following synthetic method.

(In the above formula, R ¹ , A ¹ , B ¹ , A ² , B ² , A ³ and n have the above-mentioned meanings, and i-Bu and Ph respectively mean isobutyl and phenyl.) The substituted benzonitrile or substituted cyclohexanecarbonitrile represented by the general formula (IV) is reacted with diisobutylaluminum hydride in a dry toluene solvent at low temperature. Then, the reaction solution is treated with methanol, water and hydrochloric acid, and the product is extracted with toluene. After the extract is neutralized, washed with water, dried, etc., the substituted benzaldehyde represented by the general formula (V) or the general separation / purification means such as vacuum distillation, chromatography and recrystallization is applied. Substituted cyclohexanecarbaldehyde can be obtained.

Many of the compounds represented by the general formula (IV), which are the starting materials, are themselves used as liquid crystal materials.
Other substances can be easily produced by combining these liquid crystal material compound production methods or known reactions. In addition to the production method using the nitrile derivative represented by the formula (IV) as a starting material, a substituted benzoic acid, a substituted cyclohexanecarboxylic acid, a substituted benzyl alcohol, a substituted cyclohexylmethanol, etc. are reduced or oxidized (V)
A production method using an aldehyde compound represented by the formula can also be used.

Furthermore, the aldehyde derivative (V) is reacted with methoxymethyltriphenylphosphonium chloride and a base (for example, potassium-t-butoxide, sodium methylate, phenyllithium, n-butyllithium, etc.) by a Wittig reaction to produce methoxy. The vinyl derivative (VI) is obtained. When this compound (VI) is heated under acidic conditions (for example, it is heated with hydrochloric acid in a tetrahydrofuran solvent), an aldehyde derivative (VII) having one more methylene than the original aldehyde derivative (V) can be obtained. By repeating the Wittig reaction and the acid treatment reaction m times using the aldehyde derivative (V) as a raw material, m
It is possible to obtain an aldehyde derivative (II) having 1 or more.

The compound of the formula (I) of the present invention is a liquid crystal compound having a relatively low viscosity and is suitable for producing a liquid crystal display device having a higher response speed.

The compound of the present invention is a compound having stability to heat, light, electricity, air, moisture and the like necessary for a liquid crystal display material. Further, the compound of the present invention has excellent compatibility with other liquid crystal compounds, so that a liquid crystal material suitable for various uses can be obtained by mixing with such a compound or a mixture thereof. .

Examples of the liquid crystal component used in addition to the compound of formula (I) as the component of the liquid crystal composition of the present invention include the following (i)
Liquid crystal compounds represented by the following formulas (xxxiii) are preferred.

In the formulas (i) to (xxxiii), X is , Y represents —CN, a halogen atom, R ¹ or OR ¹ , R and R ¹ represent an alkyl group, and The hydrogen atom of may be substituted with a halogen atom.

In the present invention, the liquid crystal compound or liquid crystal mixture is mixed with the compound of formula (I) in an amount of preferably 1 to 30% by weight, more preferably 5 to 20% by weight. In the formula (I), n =
If the content of the compound of 0 exceeds 30% by weight, the clearing point of the resulting composition may be greatly lowered, which is not preferable. Further, if the content of the compound of the formula (I) in which n = 1 exceeds 30% by weight, the viscosity of the obtained composition may increase, which is also not preferable.

The bicyclic compounds represented by the general formulas (1) to (16) described above have extremely low viscosity and excellent compatibility with other existing liquid crystals, and when these compounds are added to the nematic liquid crystal composition. Also has the property of not significantly lowering the nematic-isotropic liquid phase transition point. In particular, the compound of the general formula (3) is a compound having a very small Δn, and has excellent properties for preparing a liquid crystal composition having a small Δn.

Furthermore, the three-ring liquid crystal compounds of the general formulas (17) to (25) described above often have a higher clearing point than the two-ring compounds.
These are relatively low-viscosity compounds as tricyclic liquid crystal compounds.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples. In the examples, crystal-smectic phase transition point, crystal-nematic phase transition point, smectic-smectic phase transition point, smectic-nematic phase transition point, smectic-isotropic liquid phase transition point and nematic-isotropic liquid phase transition point. The points are abbreviated as CS point, CN point, SS point, SN point, SI point and NI point, respectively.

Example 1 (1) Preparation of trans-4- (trans-4-propylcyclohexyl) cyclohexanecarbaldehyde Trans-4- (trans-4-propylcyclohexyl) cyclohexanecarbonitrile 100 g (0.43 mol)
After 200 ml of toluene and 200 ml of toluene were replaced with nitrogen while stirring at 0 ° C., 300 g of a 25 wt% toluene solution of diisobutylaluminum hydride was gradually added under stirring at a reaction temperature of 5 ° C. or lower under a nitrogen stream. Reaction temperature gradually increased to 20 ℃ over 3 hours
And stirred at 20 ° C. for 10 hours under a nitrogen stream. The reaction solution was cooled to 0 ° C., and 200 ml of methanol, 200 ml of water and 500 ml of 6N hydrochloric acid were added dropwise with stirring. To the reaction solution was added 300 ml of toluene to extract the product. The toluene solution was washed 5 times with 200 ml of a saturated aqueous solution of sodium hydrogencarbonate and then washed with water until the aqueous layer became neutral, and the toluene solution was dried over anhydrous sodium sulfate. After separating the drying agent, the residue obtained by distilling off toluene was dried under reduced pressure to obtain 87 g of the desired product.
(0.37 mol) was obtained.

(2) Preparation of trans-4- (trans-4-propylcyclohexyl) cyclohexylacetaldehyde 127.5 g (0.372 mol) of commercially available methoxymethyltriphenylphosphonium chloride was added to methyl-t-butyl ether 1 and stirred in an argon atmosphere. At -10 ℃
43.1 g (0.384 mol) of potassium t-butoxide in 10 minutes
Was added. After stirring the reaction solution for 1 hour at 0 ° C., (1)
Trans-4- (trans-4-propylcyclohexyl) cyclohexanecarbaldehyde obtained in 48.9 g
A solution of (0.207 mol) in methyl-t-butyl ether (200 ml) was added dropwise at -10 ° C over 15 minutes. The reaction solution was stirred at 0 ° C. for 1 hour, and toluene 0.3 and water 0.3 were added. This toluene solution was separated and washed four times with 0.3 of water, and dried over anhydrous sodium sulfate. After separating the desiccant, the residue obtained by distilling off toluene was heated and dissolved in 100 ml of ethyl acetate, and left at room temperature for one day. The precipitated crystals were separated, the mother liquor was concentrated, dissolved in heptane and purified by silica gel column chromatography to give trans-1- (2-methoxy-1-ethenyl) -4- (trans-4-propylcyclohexyl). ) 43.1 g (0.163 mol) of cyclohexane was obtained. Tetrahydrofuran (500 ml) and 2N-hydrochloric acid (120 ml) were added to the total amount, and the mixture was heated under reflux with stirring for 1 hour and then cooled. The reaction solution is washed with 300 ml of toluene and 1 of water. This toluene solution was washed with water 1 three times,
It was dried over anhydrous sodium sulfate. After the drying agent was separated and toluene was distilled off, the obtained residue was dried under reduced pressure to obtain trans-4- (trans-4-propylcyclohexyl) cyclohexylacetaldehyde 38.0 g (0.152 mol).

(3) Preparation of trans-1- (3,3-difluoro-2-propenyl) -4-trans-4-propylcyclohexyl) cyclohexane trans-4- (trans-obtained according to (2).
4-propylcyclohexyl) cyclohexylacetaldehyde 42.0 g (0.168 mol), triphenylphosphine 5
0.6 g (0.193 mol), sodium chlorodifluoroacetate 5
1.2 g (0.336 mol) and 160 ml of dimethylformamide were heated and stirred at about 90 ° C. for 3 hours under a nitrogen stream, and then cooled to room temperature. After the reaction, 200 ml of toluene and 200 ml of water were added. This toluene solution was washed three times with 200 ml of water and dried over anhydrous sodium sulfate. After separating the desiccant, toluene was distilled off, and the obtained residue was distilled under reduced pressure. The distillate was dissolved in heptane, purified by silica gel column chromatography, recrystallized repeatedly with a mixed solvent of heptane and ethanol (1:10), and finally dried to give the desired compound trans-1- (3 18.7 g (0.0657 mol) of 3,3-difluoro-2-propenyl) -4- (trans-4-propylcyclohexyl) cyclohexane was obtained. The compound had a CS point of -11.5 ° C and an SI point of 55.4 ° C.

Similarly, using trans-4- (trans-4-pentylcyclohexyl) cyclohexanecarbonitrile as a raw material, the following trans-1- (3,3-difluoro-2-
Propenyl) -4- (trans-4-pentylcyclohexyl) cyclohexane was prepared.

 The CS point was 3.5 ° C and the SI point was 65.7 ° C.

Example 2 trans-4-propyl- (4-cyanophenyl) cyclohexane was used as a starting material, and trans-4-propyl [4- (3,3-difluoro-2-propenyl) was prepared in the same manner as in Example 1. ) Phenyl] cyclohexane was prepared. The melting point of this product was -7.0 ° C.

Example 3 4-pentyl-4 ′-(3,3-difluoro-2-propenyl) biphenyl was prepared by a method similar to that of Example 1 using 4-pentyl-4′-cyanobiphenyl as a starting material. . This product has an SS point of 36.9 ℃ and SI point of 53.1 ℃.
showed that.

Example 4 (1) Preparation of 3- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] -1-propanal 102.7 g (0.300 mol) of commercially available methoxymethyltriphenylphosphonium chloride was added to methyl-t-butyl ether. In addition to 1, at -10 ℃ under stirring in an argon atmosphere
33.7 g (0.300 mol) of potassium t-butoxide in 10 minutes
Was added. The reaction solution was stirred at 0 ° C for 1 hour and then at -10 ° C, trans-4-prepared by the method of Example 1 (2).
(Trans-4-propylcyclohexyl) cyclohexylacetaldehyde 50 g (0.200 mol) of methyl-t-
A 200 ml solution of butyl ether was added dropwise at -10 ° C over 15 minutes. After the reaction solution was stirred at 0 ° C. for 1 hour, 0.3 of toluene and 0.3 of water were added. This toluene solution was separated and washed four times with 0.3 of water, and dried over anhydrous sodium sulfate. After separating the desiccant, toluene was distilled off, and the resulting residue was dissolved by heating in 100 ml of ethyl acetate and allowed to stand at room temperature for 1 day. The precipitated crystals were separated, the mother liquor was concentrated, dissolved in heptane and purified by silica gel column chromatography to give trans-1- (3-methoxy-2-propenyl) -4- (trans-4-propylcyclohexyl). ) Cyclohexane
42.6 g (0.153 mol) was obtained. To the whole amount, 330 ml of tetrahydrofuran and 90 ml of 2N-hydrochloric acid were added, and the mixture was heated under reflux with stirring for 1 hour and then cooled. The reaction solution is washed with 300 ml of toluene and 1 of water. Add this toluene solution to water 1
It was separated and washed three times with and dried over anhydrous sodium sulfate.
After separating the desiccant, toluene was distilled off, and the obtained residue was dried under reduced pressure to give 3- [trans-4- (trans-4
35.6 g (0.135 mol) of -propylcyclohexyl) cyclohexyl] -1-propanal was obtained.

(2) Preparation of trans-1- (4,4-difluoro-3-butenyl) -4- (trans-4-propylcyclohexyl) cyclohexane 3- [trans-4- (trans-
4-propylcyclohexyl) cyclohexyl] -1-
Propanal 27.5g (0.104mol), triphenylphosphine 31.4g (0.120mol), sodium chlorodifluoroacetate 31.7g (0.208mol) and dimethylformamide 130
ml was heated and stirred at about 90 ° C. for 3 hours under a nitrogen stream, and then cooled to room temperature. After the reaction, 200 ml of toluene and 200 ml of water were added. This toluene solution was washed three times with 200 ml of water and dried over anhydrous sodium sulfate. After separating the desiccant, toluene was distilled off, and the obtained residue was distilled under reduced pressure. Dissolve the distillate in heptane and purify by silica gel column chromatography, and then heptane and ethanol (1:
Recrystallization was repeated with the mixed solvent of 10) and finally dried to obtain the desired compound trans-1- (4,4-difluoro-).
10.2 g (0.0342 mol) of 3-butenyl) -4- (trans-4-propylcyclohexyl) cyclohexane was obtained.
The compound had a CS point of -10.3 ° C and an SI point of 70.3 ° C.

Similarly, the following compounds were prepared using the corresponding aldehyde compound as a raw material.

Trans-1- (4,4-difluoro-3-butenyl)-
4- (trans-4-pentylcyclohexyl) cyclohexane CS point-22.8 ° C, SI point 85.7 ° C trans-4-propyl-1- [4- (4,4-difluoro-3-butenyl) phenyl] cyclohexane melting point -15.6 ° C 4-Pentyl-4 ′-(4,4-difluoro-3-butenyl) biphenyl CS point −25.4 ° C., SS point 30.8 ° C., SI point 50.6 ° C. Example 5 (use example 1) Of the liquid crystal composition A consisting of 72.0 ° C., the viscosity η _{20 at} 20 ° C. is 27.5 cP, Δε is 11.0 (ε _// = 15.7, ε _⊥ = 4.
7), and, [Delta] n is 0.14 (n _e = 1.63, a n _o = 1.49), although this was sealed in a TN cell having a cell thickness 10μm threshold voltage 1.83V, the saturation voltage was found to be 2.79V .

The compound of the present invention shown in Example 4 trans-1- (4,4-difluoro-3-butenyl) -4- (trans-4-propylcyclohexyl) was added to 85 parts by weight of the liquid crystal composition A.
The liquid crystal composition containing 15 parts by weight of cyclohexane has an NI point of 7
It does not drop much at 0.2 ℃, η ₂₀ is extremely reduced to 19.5 cP, Δε becomes 9.5 (ε _// = 13.9, ε _⊥ = 4.4), and Δn
Decreased to 0.12 (n _e = 1.61, n _o = 1.49). The threshold voltage (abbreviated as Vth) of this composition sealed in the above-mentioned TN cell is 1.80 V and the saturation voltage (abbreviated as Vsat) is 2.
It dropped to 77V.

Example 6 (Use Examples 2 to 8) To 85 parts by weight of the above-mentioned liquid crystal composition A, 15 parts by weight of the compound of the present invention shown in Table 1 prepared in Examples 1 to 4 was mixed, respectively, to obtain 7 kinds of liquid crystal compositions. The thing was prepared. The physical properties of these seven kinds of liquid crystal compositions are shown in FIG.
The results are shown in Table 1.

(Effects of the Invention) The present invention provides novel liquid crystal compounds and liquid crystal mixtures. The novel liquid crystalline compounds have low viscosity,
Many of them have characteristics such as small Δn and small Δε, and by utilizing these properties, a liquid crystal mixture useful as a display element material can be obtained.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C07C 43/192 C07C 43/192 43/225 43/225 C09K 19/12 C09K 19/12 19/14 19/14 19/20 19/20 19/30 19/30 19/44 19/44 // G02F 1/13 500 G02F 1/13 500

Claims (2)

(57) [Claims] 1. A general formula ^{R 1 -A 1 -B 1 -A 2} B 2 -A in _{^{3 n CH 2 m CH = CF}} 2 ( wherein, R ¹ is alkyl or the number of carbon atoms of the hydrogen or carbon number of 1 to 20 alkenyl of 2 to 20, in the alkyl and alkenyl one -CH ₂ - not adjacent groups or phase two -CH ₂ - groups may be replaced by -O- groups, double bonds The position and number can be selected arbitrarily, where A ¹ , A ² and A ³ are independent of each other. Or The hydrogen of may be replaced by fluorine, chlorine or methyl. In the formula, B ¹ and B ² are each independently --CH ₂ CH ₂ -,-
CH ₂ O—, —OCH ₂ — or a single bond, n is 0 or 1
Is an integer and m is a natural number of 1 to 20. ). Wherein the general formula ^{R 1 -A 1 -B 1 -A 2} B 2 -A in _{^{3 n CH 2 m CH = CF}} 2 ( wherein, R ¹ is alkyl or the number of carbon atoms of the hydrogen or carbon number of 1 to 20 alkenyl of 2 to 20, in the alkyl and alkenyl one -CH ₂ - not adjacent groups or phase two -CH ₂ - groups may be replaced by -O- groups, double bonds The position and number can be selected arbitrarily, where A ¹ , A ² and A ³ are independent of each other. Or The hydrogen of may be replaced by fluorine, chlorine or methyl. In the formula, B ¹ and B ² are each independently --CH ₂ CH ₂ -,-
CH ₂ O—, —OCH ₂ — or a single bond, n is 0 or 1
Is an integer and m is a natural number of 1 to 20. ) A liquid crystal composition containing a compound represented by