JPH06293690A - Liquid crystal compound and composition - Google Patents

Abstract

PURPOSE:To obtain a new liquid crystal compound having a specific structure containing a triple bond and useful as the component of ferrodielectric liquid crystal compositions exhibiting chiral smectic C phases for liquid crystal display elements, etc., enabling a high speed response. CONSTITUTION:A brominated compound of formula I (R<2> is H, 1-12C alkyl; (n) is an integer of 1-12) (e.g. 8-bromo-1-octene) is reacted with a phenol derivative of formula II (R<1> is a 4-12C alkyl; (n) is 1 or 2) containing a triple bond in a solvent such as dimethyl sulfoxide to produce the objective liquid crystal compound of formula III (A is 1,4-phenylene substituted with one or two fluorine, atoms), useful as the component of liquid crystal compositions exhibiting chiral smectic C phases, the phenol derivative being obtained by the reaction of a 4-acetoxy-fluorobromobenzene compound with p-decyloxyphenylacetylene, etc., in the presence of sodium hydroxide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel liquid crystal compound useful as a component of a liquid crystal composition used for a liquid crystal display device and the like, and a liquid crystal composition containing the liquid crystal compound. More specifically, a non-chiral smectic C phase (hereinafter referred to as Sc
The present invention provides a novel tolan-based liquid crystal compound exhibiting a phase) and a ferroelectric liquid crystal composition containing the liquid crystal compound.

[0002]

2. Description of the Related Art Recently, a display system using a ferroelectric liquid crystal compound has been reported by Meyer et al., And a high speed response and a memory effect of 100 to 1000 times that of a TN type can be obtained. Expectations are high, and research and development are currently underway. The liquid crystal phase of the ferroelectric liquid crystal compound belongs to the tilt type chiral smectic phase, but the Sc * phase, which has the lowest viscosity, is the most practically preferable. A large number of liquid crystal compounds exhibiting the Sc * phase have already been synthesized and studied, but the conditions for using as a ferroelectric liquid crystal display element are as follows.
(A) Show Sc * phase in a wide temperature range including room temperature,
Examples include (b) uniform orientation and large helical pitch, (c) proper tilt angle, and (d) low viscosity. However, no liquid crystal compound exhibiting the Sc * phase that satisfies these conditions alone is currently known, and efforts are being made to satisfy these conditions by mixing. Further, development of a novel liquid crystal compound exhibiting a Sc * phase is also underway. On the other hand, as a method for preparing a liquid crystal composition exhibiting the Sc * phase (hereinafter referred to as Sc * liquid crystal composition),
There is also a method of adding a chiral compound to a liquid crystal compound or composition that does not exhibit ferroelectricity and exhibits a non-chiral Sc phase, and development of a liquid crystal compound exhibiting a Sc phase is also underway.
Conventionally, as a tolan-based liquid crystal compound, 4-alkoxy-
4'-alkenyl oxytolan (Special table Sho 63-5022
No. 84), 4-alkoxy-3′-fluoro-
4'-alkoxy tolan (described in JP-A-3-223225) and the like are known.

[0003]

However, of the above-mentioned tolan-based liquid crystal compounds, the former has been developed for nematic liquid crystal compositions, and the excellent effect as the Sc phase cannot be expected. The latter shows the Sc phase and has a low viscosity, but a compound having a lower viscosity is desired in order to obtain a liquid crystal display device for high speed display.

[0004]

Means for Solving the Problems As a result of intensive investigations by the present inventors on a liquid crystal compound exhibiting a Sc phase and having a viscosity lower than that of the above compound, a novel liquid crystal compound having a structure different from the conventional one was found. Heading The invention has been reached. That is, the present invention provides the following general formula (1)

[0005]

[Chemical 2]

[In the formula, R ¹ represents an alkyl group having 4 to 12 carbon atoms, and A is 1,2 substituted with 1 to 2 fluorine atoms.
Represents a 4-phenylene group, n represents an integer of 1 to 12,
R ² represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom]; and a liquid crystal composition containing at least one kind of this liquid crystal compound.

In the general formula (1), the number of carbon atoms represented by R ¹ is 4
As specific examples of the alkyl group of to 12, n-butyl group,
n-pentyl group, n-hexyl group, n-heptyl group,
Examples thereof include an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, and an n-dodecyl group, and among these, a preferable one is an alkyl group having 6 to 10 carbon atoms.

N is preferably an integer of 1-10.

Specific examples of the alkyl group having 1 to 12 carbon atoms represented by R ² include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n. -Heptyl group, n-octyl group, n-nonyl group,
Examples thereof include an n-decyl group, an n-undecyl group, and an n-dodecyl group. Of these, a hydrogen atom and an alkyl group having 1 to 10 carbon atoms are preferable. Specific examples of the liquid crystal compound of the present invention include compounds having groups shown in Tables 1 and 2.

[0010]

[Table 1]

[0011]

[Table 2]

In Tables 1 and 2, each symbol represents the following group. ETY; C ₂ H ₅ -PRO; n-C ₃ H ₉ BU
_{T; n-C 4 H 9} - PEN; n-C 5 H 11 - HEX; n-C 6 H 13 - HE
P; n-C ₇ H ₁₅ -OCT; n-C ₈ H ₁₇ -NON; n-C ₉ H ₁₉ -DE
C; n-C ₁₀ H ₂₁

The compound of the present invention can be synthesized, for example, through the steps shown below (in the following formula, R ¹ , n and R ² are the same as in the case of the general formula (1)).

[0014]

[Chemical 3]

That is, the bromine compound represented by the general formula (2) is reacted with the compound represented by the general formula (3) in the presence of sodium hydroxide to give the compound of the present invention represented by the general formula (1). Can be obtained.

Alternatively, it can be synthesized through the following steps.

[0017]

[Chemical 4]

That is, by reacting the alcohol represented by the general formula (4) with the compound represented by the general formula (3) in the presence of diethylazodicarboxylate and triphenylphosphine, the compound represented by the general formula, which is the compound of the present invention, can be obtained. The compound of (1) can be obtained.

Some of the alcohols represented by the general formula (4) are commercially available, and some of them reduce the corresponding aldehyde with sodium borohydride, lithium aluminum hydride or diisobutylaluminum hydride. Can be obtained.

When R ² is a hydrogen atom, it can be synthesized through the following steps.

[0021]

[Chemical 5]

That is, the compound of the general formula (6) obtained by reacting the dibromo compound represented by the general formula (5) with the compound of the general formula (3) in the presence of sodium hydroxide is potassium-t-. By reacting with butoxide, the compound of the general formula (1 ′), which is the compound of the present invention, can be obtained.

The compound represented by the general formula (3) can be synthesized, for example, through the following steps [wherein R ¹ is the same as in the general formula (1)]. (I) When A is a monosubstituted product

[0024]

[Chemical 6]

That is, 4-acetoxy-3 obtained by reacting 4-bromo-2-fluorophenol with acetyl chloride
-Fluorobromobenzene and 4- represented by the general formula (7)-
The compound of the general formula (8) can be obtained by reacting alkoxyphenylacetylene in the presence of a palladium catalyst. By hydrolyzing the compound of general formula (8) with an alkali, a compound of general formula (3a), which is a raw material for the compound of the present invention, can be obtained. (II) When A is a disubstituted product

[0026]

[Chemical 7]

That is, 2,3-difluoro-4-iodophenol can be obtained by iodizing 2,3-difluorophenol with sodium iodide and sodium hypochlorite. 2,3-difluoro-4-
4- obtained by reacting iodophenol with acetyl chloride
A compound of the general formula (9) can be obtained by reacting acetoxy-2,3-difluoroiodobenzene with 4-alkoxyphenylacetylene represented by the general formula (7) in the presence of a palladium catalyst. By hydrolyzing the compound of general formula (9) with an alkali, a compound of general formula (3b), which is a raw material for the compound of the present invention, can be obtained.

The compound represented by the general formula (7) can be obtained by the method described in the literature (for example, JP-A-3-223225).

Generally, the liquid crystal compound is used as a component of a liquid crystal composition composed of two or more kinds of components, and the liquid crystal compound of the present invention can also be used as a component of the liquid crystal composition. The liquid crystal composition of the present invention comprises a mixture of a plurality of compounds and contains at least one liquid crystal compound of the present invention. Examples of the liquid crystal composition of the present invention include Sc
Examples thereof include a liquid crystal composition [1] exhibiting a phase and a liquid crystal composition [2] exhibiting a Sc * phase, but a liquid crystal composition exhibiting a Sc * phase is preferable.

In the liquid crystal composition [1] of the present invention, the liquid crystal compound of the present invention is used as at least one essential component, and as an optional component, a liquid crystal compound (2-4′-alkyloxyphenyl-5) showing another Sc phase. -Alkylpyrimidine, 2-4'-alkylphenyl-5-alkyloxypyrimidine, 2-4'-alkyloxyoxyphenyl-5-alkyloxypyrimidine, 2-p-alkyloxycarbonylphenyl-5-alkylpyrimidine, 2- 4'-alkyloxy-3'-fluorophenyl-5-alkylpyrimidine, 2-4'-alkyloxy-2 ', 3'-difluorophenyl-5-alkylpyrimidine, 2-4'-alkyloxyphenyl-5- Alkyl pyridine, 2-4′-alkyloxy-3′-fluorophenyl-5-alkyl pyridine, etc.), a smectic liquid crystal compound that does not exhibit a Sc phase and a nematic phase It is a mixture containing a compound selected from to the liquid crystal compound. In the liquid crystal composition [1] of the present invention, the content of one or more liquid crystal compounds of the present invention is usually 5 to 90% by weight.

The liquid crystal composition [2] of the present invention contains at least one liquid crystal compound of the present invention and a liquid crystal compound showing an Sc * phase (optically active 4-alkyloxy-4'-biphenylcarboxylic acid-p '). -(2-Methylbutyloxycarbonyl) phenyl ester, optically active 4-n-alkyloxy
-4'-biphenylcarboxylic acid-2-methylbutyl ester, optically active 4-alkyloxyphenyl-4 '-(4-methylhexyloxy) benzoate, optically active 4-alkenyloxyphenyl-4'-(4-methylhexyl (Oxy) benzoates, naphthalene compounds described in JP-A-63-233932, compounds in which an alkenyl group is introduced into naphthalene compounds described in JP-A-63-233932, and / or chiral compounds 6
3-99032, JP-A-63-190843, JP-A-2-138274, and JP-A-2-256.
No. 673, JP-A-2-262579, JP-A-2-286673, JP-A-3-27374, etc.) as an essential component, and the liquid crystal composition of the present invention [1] as an optional component. A mixture containing a compound selected from the above-mentioned liquid crystal compounds exhibiting a Sc phase, smectic liquid crystal compounds not exhibiting a Sc phase, liquid crystal compounds exhibiting a nematic phase, and dichroic dyes (anthraquinone dyes, azo dyes, etc.). Is.

In the liquid crystal composition [2] of the present invention, the content of one or more liquid crystal compounds of the present invention is usually 5 to 90% by weight, preferably 10 to 70% by weight.

The Sc * liquid crystal composition exhibiting ferroelectricity causes an optical switching phenomenon when a voltage is applied, and a liquid crystal display element having a fast response can be manufactured by utilizing this phenomenon [see, for example, JP-A-56-107216, Kaisho 59-11874
No. 4, gazette, N. A. Clark (NA Clar
k), S. tea. Ragawall (S.T.Lage
rwall); Applied Physics Letter (A
applied Physics Letter) 36 ,
899 (1980), etc.].

The liquid crystal composition of the present invention showing the Sc * phase [2]
The cell spacing is 0.5 to 10 μm, preferably 0.5 to 3 μm.
An optical switching element (liquid crystal display element) can be obtained by vacuum-sealing the liquid crystal cell of m and installing polarizers on both sides. The above liquid crystal cell can be produced by aligning the surface of a substrate provided with a transparent electrode and then bonding the two substrates with a spacer interposed therebetween. The substrate is not particularly limited, and In ₂ O ₃ , SnO
₂ , a glass provided with In ₂ O ₃ —SnO ₂ or the like, a substrate such as a polyester film, a thin film transistor, a substrate on which a diode is formed, or the like. Examples of the spacer include alumina beads, glass fiber, polyimide film and the like. As an alignment treatment method, a normal alignment treatment, for example, a rubbing treatment of a polyimide film, an oblique SiO vapor deposition, or the like can be applied.

[0035]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. The structure of the compound was confirmed by NMR (nuclear magnetic resonance spectrum analysis), MS (mass spectrometry) and elemental analysis. Example 1 No. 1 in Table 1 Preparation of Compound 12 4-Bromo-2-fluorophenol 19.1 g, pyridine 1
10g in a solution of 6.0g dry diethyl ether in 150ml
Acetyl chloride (10.0 g) was added dropwise at a temperature of not higher than 0 ° C. After the dropping is completed,
The mixture was heated under reflux for 2 hours. After pouring it into ice water, remove the ether layer
After washing with 1N hydrochloric acid and washing with water, ether was removed to obtain 20.5 g of liquid 4-acetoxy-3-fluorobromobenzene. 4-acetoxy-3-fluorobromobenzene 1 obtained in
0.0g (42.9 mmol) and 11.1 g (42.9 mmol) of p-decyloxyphenylacetylene in 200 ml of triethylamine were used as catalysts for dichlorobistriphenylphosphine palladium (I
I) 152 mg (0.2 mmol), copper (I) iodide 38 mg (0.2 mmo
l) and 304 mg (1.1 mmol) of triphenylphosphine were heated to reflux under a nitrogen atmosphere for 8 hours. After completion of the reaction, triethylamine was removed and the mixture was extracted with hexane. The hexane layer was washed with 1N aqueous hydrochloric acid and washed with water, and then hexane was removed to obtain 14.9 g (37.8 mmol) of solid 4-decyloxy-4′-acetoxy-3′-fluorotran. 10 ml of an aqueous solution prepared by dissolving 14.9 g (37.8 mmol) of 4-decyloxy-4′-acetoxy-3′-fluorotran obtained in step 200 in ethanol and 3.0 g (76.0 mmol) of sodium hydroxide.
Was added and the mixture was heated under reflux for 2 hours. After cooling to room temperature, ethanol was removed and 1N hydrochloric acid water was added. The precipitated precipitate was collected by filtration and recrystallized from hexane to give 4-decyloxy-4 '.
11.8 g (32.1 mmol) of -hydroxy-3'-fluorotran was obtained. 2.0 g (5.4 mmol) of 4-decyloxy-4'-hydroxy-3'-fluorotolan obtained in 1., 0.65 g of 5-hexenol
(6.5 mmol) and 1.7 g (6.5 mmol) of triphenylphosphine were dissolved in 30 ml of dry tetrahydrofuran, 1.1 g (6.5 mmol) of diethylazodicarboxylate was added thereto at 10 ° C or lower, and the mixture was stirred at room temperature overnight. Tetrahydrofuran was distilled off and then extracted with hexane. Hexane was distilled off, and the obtained solid was purified by a silica gel column and recrystallized from ethanol three times to give N of the compound of the present invention in Table 1.
o. 1.6 g of 12 compounds are obtained. ¹ H-NMR (ppm) 0.87 (t, 3H) 1.22-1.62 (m, 16H) 1.72-
1.87 (m, 4H) 2.12 (dd, 2H) 3.93 (t, 2H) 4.03 (t, 2H) 4.96 ~
5.07 (m, 2H) 5.75 ~ 5.88 (m, 1H) 6.82 (d, 2H) 6.88 (t, 1H)
7.18〜7.22 (m, 2H) 7.42 (d, 2H) ¹⁹ F-NMR (ppm) -58.68 (t, 1F) Elemental analysis value Theoretical value (%) Actual value (%) C: 79.96 C: 80.05 H: 8.72 H: 8.66 F: 4.22 F: 4.35

Example 2 No. 1 in Table 1 Preparation of 14 compound 4-decyloxy-4′-hydroxy-3′-fluorotolan 2.0 g (5.4 mmol), sodium hydroxide 0.26 g (6.5 mmo
5 ml of an aqueous solution prepared by dissolving l) was added into 30 ml of dimethylsulfoxide and stirred until the solution became uniform. Then, 1.2 g (6.5 mmol) of 8-bromo-1-octene was added, and the mixture was stirred at room temperature for 3 days. After completion of the reaction, the mixture was poured into ice water. The obtained solid was isolated by suction filtration, dried, dissolved in toluene and purified by a silica gel column. Then, it was recrystallized three times with ethanol to give the compound of the present invention, No. 1 in Table 1.
1.6 g of 14 compounds are obtained. ¹ H-NMR (ppm) 0.87 (t, 3H) 1.22-1.50 (m, 20H) 1.72-
1.85 (m, 4H) 2.05 (dd, 2H) 3.94 (t, 2H) 4.02 (t, 2H) 4.91 ~
5.03 (m, 2H) 5.74 ~ 5.88 (m, 1H) 6.84 (d, 2H) 6.88 (t, 1H)
7.18 ~ 7.24 (m, 2H) 7.42 (d, 2H) ¹⁹ F-NMR (ppm) -58.74 (t, 1F) Elemental analysis value Theoretical value (%) Actual value (%) C: 80.29 C: 80.18 H: 9.05 H: 9.22 F: 3.97 F: 4.01

Example 3 No. 1 in Table 1 Preparation of Compound 15 In place of 5-hexenol in Example 1, trans
Example 1 except that 2-hexenol was used in the same molar ratio.
By performing the same operation as No. 1 in Table 1 which is a compound of the present invention. 1.6 g of 15 compounds are obtained. ¹ H-NMR (ppm) 0.83 to 0.91 (m, 6H) 1.22 to 1.48 (m, 16H)
1.71 to 1.81 (m, 2H) 2.05 (dd, 2H) 3.95 (t, 2H) 4.55 (dd, 2
H) 5.64 to 5.73 (m, 1H) 5.80 to 5.90 (m, 1H) 6.83 (d, 2H) 6.
90 (t, 1H) 7.18 to 7.22 (m, 2H) 7.42 (d, 2H) ¹⁹ F-NMR (ppm) -58.24 (t, 1F) Elemental analysis value Theoretical value (%) Actual value (%) C: 79.96 C: 79.79 H: 8.72 H: 8.91 F: 4.22 F: 4.11

Example 4 No. 1 in Table 1 Preparation of Compound 16 In place of 5-hexenol in Example 1, trans
Example 1 except that -2-heptenol was used in the same molar ratio.
By performing the same operation as No. 1 in Table 1 which is a compound of the present invention. 1.6 g of 16 compounds are obtained. ¹ H-NMR (ppm) 0.84 to 0.92 (m, 6H) 1.22 to 1.48 (m, 18H)
1.72 to 1.81 (m, 2H) 2.08 (dd, 2H) 3.96 (t, 2H) 4.54 (dd, 2
H) 5.64 to 5.73 (m, 1H) 5.80 to 5.90 (m, 1H) 6.83 (d, 2H) 6.
90 (t, 1H) 7.18 to 7.22 (m, 2H) 7.42 (d, 2H) ¹⁹ F-NMR (ppm) -58.22 (t, 1F) Elemental analysis value Theoretical value (%) Actual value (%) C: 80.13 C: 79.99 H: 8.89 H: 8.97 F: 4.09 F: 4.11

Example 5 No. 1 in Table 1 Preparation of Compound 17 In place of 5-hexenol in Example 1, cis-
Example 1 except that 3-hexenol was used in the same molar ratio.
By performing the same operation as No. 1 in Table 1 which is a compound of the present invention. 1.3 g of 17 compound is obtained. ¹ H-NMR (ppm) 0.87 (t, 3H) 0.98 (t, 3H) 1.22 to 1.49 (m,
14H) 1.71 ~ 1.81 (m, 2H) 2.03 ~ 2.13 (m, 2H) 2.58 (d, 2H)
3.94 (t, 2H) 4.03 (t, 2H) 5.37 ~ 5.46 (m, 1H) 5.50 ~ 5.60
(m, 1H) 6.83 (d, 2H) 6.89 (t, 1H) 7.19 ~ 7.23 (m, 2H) 7.42
(d, 2H) ¹⁹ F-NMR (ppm) -58.50 (t, 1F) Elemental analysis value Theoretical value (%) Actual value (%) C: 79.96 C: 80.00 H: 8.72 H: 8.66 F: 4.22 F: 4.25

Example 6 In Table 2, No. Preparation of 31 compound 2,3-difluorophenol 70.0 g, sodium iodide 80.7 g and sodium hydroxide 21.5 g in methanol 1400
After dissolving in 100 ml and cooling to 0 ° C., 1000 ml of 4% sodium hypochlorite aqueous solution was added dropwise. After the completion of dropping, the mixture was stirred at 0 ° C to 5 ° C for 3 hours. Sodium thiosulfate was added to the reaction mixture to reduce excess iodine, which was then neutralized with hydrochloric acid, extracted with ether and washed with water. After removing the ether, the obtained solid was recrystallized twice with hexane to obtain 96.0 g of white solid 2,3-difluoro-4-iodophenol. 2,3-difluoro-4-iodophenol 25 obtained in.
6g, 16.0g pyridine dissolved in dry diethyl ether 150
10.0 g of acetyl chloride was added dropwise to the solution of ml at 10 ° C or lower.
After completion of dropping, the mixture was heated under reflux for 2 hours. After throwing in ice water,
The ether layer was washed with 1N hydrochloric acid, washed with water, and then the ether was removed to give solid 4-acetoxy-2,3.
-28.6 g of difluoroiodobenzene were obtained. In Example 1, except that 4-acetoxy-2,3-difluoroiodobenzene was used in place of 4-acetoxy-3-fluorobromobenzene in Example 1-
4-decyloxy-
2 ', 3'-Difluoro-4'-hydroxytolan was obtained. In Example 2, 4-decyloxy-3′-fluoro-
4-decyloxy-in place of 4'-hydroxytolan
By repeating the same operation as in Example 2 except that 2 ′, 3′-difluoro-4′-hydroxytran was used in the same molar ratio, the compound of the present invention, No. 2 in Table 2, was used. 1.6 g of 31 compounds are obtained. ¹ H-NMR (ppm) 0.87 (t, 3H) 1.22〜1.51 (m, 20H) 1.72〜
1.85 (m, 4H) 2.05 (dd, 2H) 3.94 (t, 2H) 4.02 (t, 2H) 4.92 ~
5.03 (m, 2H) 5.74 ~ 5.88 (m, 1H) 6.68 (dt, 1H) 6.86 (d, 2H)
7.13 (dt, 1H) 7.45 (d, 2H) ¹⁹ F-NMR (ppm) -58.33 (dd, 1F) -83.00 (dd, 1F) Elemental analysis value Theoretical value (%) Actual value (%) C: 77.38 C : 77.51 H: 8.52 H: 8.37 F: 7.65 F: 7.44

Example 7 In Table 2, No. Preparation of compound 33. 4-decyloxy-3'-fluoro-4 'in Example 4
4-decyloxy-2 ', instead of hydroxytran
By repeating the same operation as in Example 4 except that 3′-difluoro-4′-hydroxytolan was used in the same molar ratio, the compound of the present invention, No. 3 in Table 2, was used. 33 compounds 1.
Got 5g. ¹ H-NMR (ppm) 0.85-0.92 (m, 6H) 1.22-1.49 (m, 18H)
1.72 to 1.82 (m, 2H) 2.08 (dd, 2H) 3.96 (t, 2H) 4.58 (d, 2H)
5.62 to 5.73 (m, 1H) 5.80 to 5.90 (m, 1H) 6.69 (dt, 1H) 6.8
5 (d, 2H) 7.14 (dt, 1H) 7.47 (d, 2H) ¹⁹ F-NMR (ppm) -58.20 (dd, 1F) -82.41 (dd, 1F) Elemental analysis value Theoretical value (%) Actual value ( %) C: 77.14 C: 77.02 H: 8.35 H: 8.55 F: 7.87 F: 7.74

Example 8 No. 2 in Table 2 Preparation of Compound 34 In place of trans-2-heptenol in Example 7, cis
By repeating the same operation as in Example 7 except that 3--3-nonenol was used in the same molar ratio, No. 1.3 g of 34 compound was obtained. ¹ H-NMR (ppm) 0.85-0.92 (m, 6H) 1.22-1.49 (m, 18H)
1.72 to 1.82 (m, 2H) 2.08 (dd, 2H) 3.96 (t, 2H) 4.58 (d, 2H)
5.62 to 5.73 (m, 1H) 5.80 to 5.90 (m, 1H) 6.69 (dt, 1H) 6.8
5 (d, 2H) 7.14 (dt, 1H) 7.47 (d, 2H) ¹⁹ F-NMR (ppm) -58.20 (dd, 1F) -82.41 (dd, 1F) Elemental analysis value Theoretical value (%) Actual value ( %) C: 77.14 C: 77.02 H: 8.35 H: 8.55 F: 7.87 F: 7.74

Table 3 shows the phase transition temperatures of the compounds obtained in Examples 1 to 8.

[0044]

[Table 3] ------------------------------------------------------ Examples ‖ Compound ‖ Phase transition temperature (° C. ) −−−−−−−−−−−−−−−−−−−−−−−−− No. ‖No. ‖ Cry S ₁ S _C Nem Iso −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 1 ‖ 12 ‖ ・ 45.2 (・ 42.2) ・ 56.8 ・ 69.7 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 2 ‖ 14 ‖ ・49.7 (・ 43.8) ・ 60.8 ・ 71.9 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 3 ‖ 15 ‖・ 46.8 ・ 63.4 ・ 66.6 ・ 78.3 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 4 ‖ 16 ‖ ・47.3 ・ 68.5 ・ 68.6 ・ 74.7 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 5 ‖ 17 ‖ ・ 47.2 (・ 39.2) ・ 54.5 ・ 63.7 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 6 ‖ 31 ‖・ 43.4-・ 54.5 ・ 76.2 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 7 ‖ 33 ‖ ・ 33.3 -・ 58.5 ・ 76.3 ・ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 8 ‖ 34 ‖ ・ 33.3 ・ 87.0・ 87.1-・ ----------------------------

Each symbol in Table 3 has the following meaning. Cry; Crystal phase S ₁ ; Unidentified smectic phase S _C ; Smectic C phase Nem; Nematic phase Iso; Isotropic liquid phase ・; Phase exists-; Phase does not exist

All the compounds show the Sc phase.

Examples 9 to 11 and Comparative Example 1 A composition (A) was prepared by mixing the pyrimidine compounds represented by Chemical Formulas 8 to 13 below and the optically active compounds in the proportions shown in Table 4. To this composition, 10% by weight of the compound of the present invention (Compound Nos. 12, 15 and 17) was added,
A liquid crystal composition of the present invention was obtained. Further, Comparative Example 1 was prepared by adding 10% by weight of a liquid crystal compound represented by the following Chemical Formula 14 to the composition (A).

[0048]

[Chemical 8]

[0049]

[Chemical 9]

[0050]

[Chemical 10]

[0051]

[Chemical 11]

[0052]

[Chemical 12]

[0053]

[Chemical 13]

[0054]

[Chemical 14]

In Chemical formula 13, C * represents an asymmetric carbon atom. Next, a glass substrate with a transparent electrode is coated with polyimide as an orientation treatment agent, the surface is rubbed, a spacer is interposed, and the rubbing directions are laminated so as to be antiparallel,
A cell having a cell thickness of 2 μm was prepared. The composition (A), the liquid crystal composition of the present invention and the composition of Comparative Example 1 were respectively injected into this cell to prepare a liquid crystal cell, which was placed between two orthogonal polarizers at 25 ° C. , ± 10 V / μm voltage (E) was applied, and the response speed (τ) was measured. The results are shown in Table 5.

[0056]

[Table 5]

Examples 12 to 14 and Comparative Example 2 The composition of the present invention (Compound No. 3) was added to the composition (A).
1, 33 and 34) was added in an amount of 10% by weight to obtain a liquid crystal composition of the present invention. Further, a liquid crystal compound represented by the following Chemical formula 15 was added to the composition (A) in an amount of 10% by weight to prepare Comparative Example 2.
The response speed was measured in the same manner as above, and the results are shown in Table 6.
It was shown to.

[0058]

[Chemical 15]

[0059]

[Table 6]

When the cell thickness, temperature and applied voltage are the same, there is a proportional relationship between the response speed and the viscosity, and a composition having a shorter response speed has a lower viscosity.

[0061]

The liquid crystal compound of the present invention exhibits the Sc phase and has a low viscosity. Therefore, when it is used as a component of the Sc * liquid crystal composition, the viscosity can be lowered and a high speed response can be realized. Therefore, the compounds and compositions of the present invention are useful as liquid crystal materials used in liquid crystal display devices.

[Table 4]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuro Yanagi 1 1-11, Hitotsubashi-honcho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd.

Claims (2)

[Claims] 1. The following general formula (1): [In the formula, R ¹ represents an alkyl group having 4 to 12 carbon atoms, and A 1
Represents a 1,4-phenylene group substituted with 1 to 2 fluorine atoms, n represents an integer of 1 to 12, R ² represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom]. Liquid crystal compound. 2. A liquid crystal composition comprising a mixture of a plurality of compounds and containing at least one liquid crystal compound according to claim 1.