JP3147187B2 - 4-substituted-3-fluorotrifluoromethylbenzene derivatives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a 4-substituted-3-fluorotrifluoromethylbenzene derivative and a liquid crystal composition containing the compound as an active ingredient.

[0002]

2. Description of the Related Art A liquid crystal display device utilizes an optical anisotropy and a dielectric anisotropy of a liquid crystal material. Depending on the display mode, a TN type (twisted nematic type) and a DS type (dynamic scattering type) are used. ), Guest-host type, DAP type, etc., and the properties of liquid crystal materials suitable for each use are different. However, any liquid crystal substance has moisture, air,
It is common to be stable to heat, light, etc., it shows a liquid crystal phase in the widest possible temperature range around room temperature, and furthermore, the optimal dielectric anisotropy that varies depending on the type of display element Value (△ ε). However, at present, no single compound satisfies such conditions, and at present, a liquid crystal composition obtained by mixing several types of liquid crystal compounds and non-liquid crystal compounds is used. In recent years, particularly, a liquid crystal display element having a higher display quality has been demanded, and a display element using a TFT (thin film transistor) has been developed to meet the demand. As the liquid crystal required for the TFT type liquid crystal display element, it is necessary to use a compound having a large specific resistance value. As a general liquid crystal compound, a compound having a cyano group is often used, and it is known that a cyano group is decomposed when used in a TFT type liquid crystal display element to which a high voltage is applied. As prior arts, JP-A-57-64626 and JP-A-58-201734 disclose compounds of the following formula:

[0003]

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Have been disclosed. Δ 化合物 (dielectric anisotropy value) of this compound is about +2.
Further, Mol. Cryst. Liq. Cryst. Vol 42, 77 (1988) and JP-A-59-78129 disclose bicyclic and tricyclic compounds represented by the following formulae.

[0005]

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It has been disclosed that Δ △ is about +
It was about 8. Adjustment of the operating voltage is required for liquid crystal display elements, especially elements using TFTs. Therefore, the components of the liquid crystal used therein have various values of Δε required for them, and are electrically and chemically stable. Compounds are required. Further, compatibility with various other liquid crystal compounds is required for use as a composition.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal having a low viscosity, a large Δε of about +8, being electrically and chemically stable, and having good compatibility with other liquid crystal compounds. And a liquid crystal composition.

[0008]

According to the present invention, there is provided a compound of the general formula

[0009]

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(Wherein R is hydrogen or C 1 -C 15)
And m and n are each independently 0 or 1, and when m is 0, n is 0
Represented by 4-substituted-3-fluoro-trifluoromethylbenzene derivatives and the compounds in that) is a liquid crystal composition containing as an active ingredient. Since the compound of the present invention exhibits a relatively large positive dielectric anisotropy value, has a low viscosity, is electrically stable, and is stable to heat, air, light, etc., it has a TFT type liquid crystal display. It is extremely useful for obtaining a liquid crystal composition used for a device.

The liquid crystal composition provided by the present invention comprises:
In addition to the component (A) containing at least one compound represented by the formula (I), a component (B) containing one or more compounds having a high dielectric anisotropy, preferably {ε ≧ 5, | ε | <5
(C) containing one or more compounds having a low dielectric anisotropy, a component (D) containing one or more compounds having a clearing point exceeding 80 ° C., and optionally other components (E). ).

Particularly preferred compounds as component (B) are shown below.

[0013]

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[0014]

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Here, R represents an alkyl or alkenyl group having 1 to 10 carbon atoms, and one or two non-adjacent carbon atoms of the group may be replaced by an oxygen atom. Particularly preferred compounds as the component (C) are shown below.

[0016]

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[0017]

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[0018]

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Here, R and R 'represent an alkyl group or an alkenyl group having 1 to 10 carbon atoms, and one or two non-adjacent carbon atoms of the group may be replaced by an oxygen atom. Particularly preferred compounds as the component (D) are shown below.

[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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Here, R and R 'represent an alkyl group or an alkenyl group having 1 to 10 carbon atoms, and one or two non-adjacent carbon atoms of the group may be replaced by an oxygen atom. Particularly preferred compounds as the component (E) are shown below.

[0031]

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[0032]

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Here, R represents an alkyl or alkenyl group having 1 to 10 carbon atoms, and one or two non-adjacent carbon atoms of the group may be replaced by an oxygen atom. Next, the production method of the compound of the present invention will be described. In the formula (I), the compound 1-trifluoromethyl-
In the case of 3-fluoro-4- (trans-4-alkylcyclohexyl) benzene, 3-fluoro-4-bromobenzotrifluoride is reacted with shaved magnesium in a tetrahydrofuran solvent (abbreviated as THF) as shown below. Thus, a Grignard reagent was prepared, and then the Grignard reagent was reacted with trans-4-alkylcyclohexanone to produce alcohol derivative 4 . The alcohol 4 was subjected to a dehydration reaction using p-toluenesulfonic acid as a catalyst to give 1-trifluoromethyl-3-fluoro-4.
-(Trans-4-Alkylcyclohexen-1-yl) benzene 5 was produced. Then, this compound is subjected to catalytic reduction under pressure using Raney nickel as a catalyst, and the obtained trans form is purified by recrystallization to obtain the desired 1-trifluoromethyl-3-fluoro-4- (trans-4
-Alkylcyclohexyl) benzene 1 was prepared.

[0034]

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Next, a compound 2- (trans-4-alkylcyclohexyl)-wherein m = 1 and n = 0 in the formula (I)
In the case of 1- (2-fluoro-4-trifluoromethylphenyl) ethane, a Grignard reagent prepared from 3-fluoro-4-bromobenzotrifluoride in the same manner as in the case of the production of compound 1 as described below Trans-4-alkylcyclohexylacetyl chloride 6 was reacted with iron acetylacetonate as a catalyst to produce ketone body 7 . Next, after reducing 7 with lithium aluminum hydride to form an alcohol form 8 , a dehydration reaction was carried out using p-toluenesulfonic acid as a catalyst to give 2- (trans-4-alkylcyclohexyl) -1- (2-fluoro-4 -Trifluoromethylphenyl) ethene 9 was prepared. Then, this compound is subjected to catalytic reduction under pressure using palladium-carbon as a catalyst to obtain the desired 2- (trans-
4-alkylcyclohexyl) -1- (2-fluoro-
4-trifluoromethylphenyl) ethane 2 was prepared.

[0036]

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Next, in the formula (I), the compound 2- (trans-4-alkylcyclohexyl) -1- in which m = n = 1 is used.
In the case of [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane,
Reaction of Grignard reagent prepared from 3-fluoro-4-bromobenzotrifluoride with 4- (trans-4-alkylcyclohexylethyl) cyclohexanone 10 in the same manner as in the production of compound 1
11 were produced. This 11 was subjected to a dehydration reaction using p-toluenesulfonic acid as a catalyst to give 2- (trans-4-alkylcyclohexyl) -1- [4- (2-fluoro-
4-trifluoromethylphenyl) cyclohexene-1
-Yl] ethane 12 was produced. Then, this compound is subjected to catalytic reduction under pressure using Raney nickel as a catalyst,
Further, the obtained trans form was purified by recrystallization to obtain the desired 2-
(Trans-4-alkylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane 3 was produced.

[0038]

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[0039]

The compound of the present invention has good compatibility with many other liquid crystal compounds, that is, liquid crystal compounds of ester type, Schiff base type, biphenyl type, phenylcyclohexane type and heterocyclic type. By adding the compound of formula (1) as a component of the liquid crystal composition, it is possible to adjust the magnitude of Δε without increasing the viscosity so much, and to obtain an extremely chemically stable liquid crystal composition having various threshold voltages. Can be. Also, the NI point of the composition can be increased.

[0040]

EXAMPLES The production methods and use examples of the compounds of the present invention will be described in more detail with reference to the following examples. Example 1 [1-trifluoromethyl-3-fluoro-4- (trans-4-Puropirushi Kurohekishiru) benzene ((m = n = 0, R = C 3 H 7 of also of the compounds of I) type) Production] (No. 1) The reaction step is divided into three steps of 1) Grignard reaction, 2) dehydration reaction of alcohol, and 3) catalytic hydrogenation of cyclohexene derivative. Hereinafter, details of each manufacturing process will be described.

1) Grignard reaction The Grignard reagent was prepared according to a conventional method. That is, 3.7 g of shaved magnesium and 30 ml of ether were placed in a flask, and 40 ml of an ether solution of 34.7 g of 3-fluoro-4-bromobenzotrifluoride was added thereto.
Was added dropwise at room temperature while maintaining the internal temperature at 20 ° C. for about 1 hour. The mixture was stirred and aged for 2 hours at the same temperature to prepare a Grignard reagent. The product thus obtained is 2-fluoro-4-trifluoromethylphenyl magnesium bromide. After aging, 20 ml of an ether solution of 10 g (0.071 mol) of 4-propylcyclohexanone was added dropwise over 40 minutes so that the inside of the system was refluxed, and then the mixture was heated and refluxed for 2 hours. After the completion of the reflux, 60 ml of a 6N hydrochloric acid aqueous solution was added dropwise under ice cooling to terminate the reaction. The reaction solution was transferred to a separatory funnel, washed successively with water (200 ml), a saturated aqueous solution of sodium hydrogen carbonate (100 ml) and water (200 ml), and dried over anhydrous magnesium sulfate. Crude alcohol [1-trifluoromethyl-3-fluoro-4- (4-propylcyclohexyl-
1-Ol) benzene] 37.7 g (yield 54)
%). The obtained reaction mixture was directly used for the next dehydration reaction step.

2) Dehydration reaction A sample crude alcohol mixture [1-trifluoromethyl-3-fluoro-4- (4-propylcyclohexyl-1) was placed in a 200 ml three-necked flask equipped with a drain tube, a cooling tube and a stirrer. -Ol) benzene] 37.7 g, p-toluenesulfonic acid monohydrate 0.67 g and toluene 90 ml
Was added and heated under reflux for 3 hours to carry out a dehydration reaction. After the reaction was completed, the reaction mixture was allowed to cool to room temperature, washed sequentially with 100 ml of a saturated aqueous solution of sodium hydrogencarbonate and 200 ml of water, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain 35.0 g of a reaction mixture. The obtained reaction mixture was subjected to silica gel column chromatography using an ethyl acetate-heptane-based mixed solvent as an elution solvent, followed by distillation under reduced pressure to collect a fraction at 117 to 125 ° C / 2 mmHg. Further, the distillate was recrystallized with ethanol as a solvent to obtain 6.27 g (yield: 29.5%) of colorless crystals. This is 1-trifluoromethyl-3-fluoro-4- (propylcyclohexen-1-yl) benzene.

[0043]

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3) Catalytic hydrogenation of cyclohexene derivative 6.27 g of 1-trifluoromethyl-3-fluoro-4- (propylcyclohexen-1-yl) benzene was dissolved in 50 ml of ethyl acetate and developed Raney nickel catalyst.
0 g (wet) was added, and the hydrogen pressure was 5 to 10 kg / cm at room temperature.
^The mixture was stirred for 19 hours while hydrogen was added in ² to perform a catalytic hydrogenation reaction. After completion of the reaction, the catalyst was filtered off, and the solvent was distilled off under reduced pressure to obtain 6.0 g of a reaction mixture. The obtained reaction mixture was purified by silica gel column chromatography using heptane as an eluting solvent, and then recrystallized repeatedly using dry ice in ethanol to obtain 1-trifluoromethyl-3-fluoro-4- (trans 1.3 g of (-4-propylcyclohexyl) benzene (yield 2
1.5%).

[0045]

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¹ H-NMR δ (ppm) CDCl ₃
TMS internal standard 0.8 to 2.1 (16H, m) 2.87 (1H, m, Ph-CH) 7.16 to 7.40 (3H, m, Ph) Alkyl group instead of 4-propylcyclohexanone Using a different 4-alkylcyclohexanone
Trifluoromethyl-3-fluoro-4- (trans-
4-Alkylcyclohexyl) benzene can be produced.

1-trifluoromethyl-3-fluoro-4- (trans-4-methylcyclohexyl) benzene (No. 2) 1-trifluoromethyl-3-fluoro-4- (trans-4-ethylcyclohexyl) benzene (No. 3) 1-trifluoromethyl-3-fluoro-4- (trans-4-butylcyclohexyl) benzene (No. 4) 1-trifluoromethyl-3-fluoro-4- (trans-4-pentylcyclohexyl) ) Benzene (No. 5) 1-trifluoromethyl-3-fluoro-4- (trans-4-hexylcyclohexyl) benzene (No. 6) 1-trifluoromethyl-3-fluoro-4- (trans-4- Heptylcyclohexyl) benzene (No. 7) 1-trifluoromethyl-3-fluoro-4- (trans-4 -Octylcyclohexyl) benzene (No. 8) 1-trifluoromethyl-3-fluoro-4- (trans-4-nonylcyclohexyl) benzene (No. 9) 1-trifluoromethyl-3-fluoro-4- (trans -4-decylcyclohexyl) benzene (No. 10) 1-trifluoromethyl-3-fluoro-4- (trans-4-undecylcyclohexyl) benzene (No. 11) 1-trifluoromethyl-3-fluoro-4- (Trans-4-dodecylcyclohexyl) benzene (No. 12) 1-trifluoromethyl-3-fluoro-4- (trans-4-tridecylcyclohexyl) benzene (No. 13) 1-trifluoromethyl-3-fluoro- 4- (trans-4-tetradecylcyclohexyl) benzene (No. 14) 1- Trifluoromethyl-3-fluoro-4- (trans-4-pentadecylcyclohexyl) benzene (No. 15) Example 2 [2- (trans-4-propylcyclohexyl) -1- (2-fluoro-4-trifluoro) Production of methylphenyl) ethane (m = 1, n = 0, R = C ₃ H ₇ in the compound of formula (I)) (No. 16) The reaction step is 1) Grignard reaction, 2) reduction reaction, 3)
It is divided into four steps of dehydration reaction and 4) catalytic hydrogenation with palladium-carbon. Hereinafter, details of each manufacturing process will be described.

1) Grignard reaction A three-necked flask equipped with a condenser, a thermometer, a dropping funnel and a stirrer was charged with 2.05 g (0.086 g) of shaved magnesium.
mol) and THF (40 ml), and 3-fluoro-4-bromobenzotrifluoride 1 was added while maintaining the internal temperature at 25 ° C.
40 ml of a 8.9 g THF solution was added dropwise over about one hour. The mixture was aged for 3.5 hours while stirring at room temperature to prepare a Grignard reagent. Meanwhile, in a separately prepared three-necked flask, 12.2 g of trans-4-propylcyclohexylacetyl chloride and 0.4 of iron (III) acetylacetonate
After 2 g and 20 ml of THF were added and the mixture was cooled to 0 ° C. under ice cooling, the above-prepared Grignard reagent was added dropwise over 20 minutes while maintaining the temperature at 0 ° C. After completion of the dropwise addition, the mixture was aged for 2 hours at the same temperature, and then cooled under ice-cooling so as not to exceed 3 ° C.
Then, 30 ml of a 6N hydrochloric acid aqueous solution was added dropwise to terminate the reaction. After the reaction solution was extracted with toluene (400 ml), the extracted layer was washed successively with 100 ml of a 6N aqueous hydrochloric acid solution and water until the mixture became neutral, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain 30.3 g of the reaction mixture. Obtained. The reaction mixture was repeatedly recrystallized with ethanol as a solvent to give colorless crystals.13.
2 g (70.1% yield) was obtained. This is [2- (trans-4-propylcyclohexyl)]-2-fluoro-4
-Trifluoromethylacetophenone.

[0049]

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¹ H-NMR δ (ppm) CDCl ₃ TMS internal standard 0.8 to 2.0 (17 H, m) 2.85 (1 H, d, J = 6.5, 2.9 Hz, —CH ₂ — ) 7.41 (1H, dd, J = 、 １2.0, 10.7 Hz, Ph-3) 7.49 (1H, dd, J = 、 2.0, 6.8 Hz, Ph-5) 7.91 (1H, dd, J = 6.8, -7.2 Hz, Ph-6) 2) Reduction reaction Lithium aluminum in 50 ml of THF under a nitrogen atmosphere in a three-necked flask equipped with a dropping funnel, a thermometer and a nitrogen inlet tube. After adding 0.79 g of hydride and cooling to 0 ° C. under ice-cooling, 50 ml of a THF solution containing 13.2 g of [2- (trans-4-propylcyclohexyl)]-2-fluoro-4-trifluoromethylacetophenone was added at less than 5 ° C. It takes 40 minutes to keep did. After completion of the dropwise addition, the mixture was stirred at the same temperature for 3.5 hours. Next, 25 ml of ethyl acetate, 50 ml of water and 50 ml of a 6N hydrochloric acid aqueous solution were added to terminate the reaction. The reaction solution was transferred to a separating funnel and then toluene (10
0 ml), extracted with 6N hydrochloric acid aqueous solution 100 ml, water 100 m
l, washed successively with 100 ml of a saturated aqueous solution of sodium hydrogencarbonate and water (200 ml), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure.
g was obtained. This is 2- (trans-4-propylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane-1-ol. The alcohol mixture was used directly in the next dehydration reaction without purification.

[0051]

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¹ H-NMR δ (ppm) CDCl ₃
TMS internal standard 0.7 to 2.4 (20H, m) 5.12 (1H, bs, -OH) 7.18 to 7.72 (3H, m, Ph) 3) Dehydration reaction Drainage tube, thermometer And 2- (trans-4-propylcyclohexyl) -1- in an eggplant flask equipped with a condenser tube
16.8 g of (2-fluoro-4-trifluoromethylphenyl) ethane-1-ol, 0.8 g of p-toluenesulfonic acid monohydrate and 50 ml of toluene were added, and heated with a magnetic stirrer for 9 hours. Reflux was performed. After cooling to room temperature, 200 ml of water was added and the mixture was transferred to a separating funnel.
The mixture was washed with 200 ml of a saturated aqueous solution of sodium hydrogencarbonate and further with 400 ml of water, dried over anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure to obtain 13.3 g of a reaction mixture. The reaction mixture was subjected to silica gel column chromatography using heptane as an eluent to separate polar substances, and then recrystallized repeatedly with a mixed solvent of ethanol-ethyl acetate to obtain 5.6 g of colorless crystals (yield: 44.7%). . This is 2-
(Trans-4-propylcyclohexyl) -1- (2
-Fluoro-4-trifluoromethylphenyl) ethene.

[0053]

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¹ H-NMR δ (ppm) CDCl ₃
TMS internal standard 0.8-2.0 (17H, m) 6.30 (1H, dd, J = 16.2 and 5.7)
6Hz, PhCH = C H -) 6.54 (1H, d, J = 16.2Hz, PhC H = C
H-) 7.18-7.64 (3H, m, Ph) 4) Catalytic hydrogenation with palladium-carbon 2- (trans-4-propylcyclohexyl) -1-
5.6 g of (2-fluoro-4-trifluoromethylphenyl) ethene was added to ethanol 60 in a 100 ml eggplant flask.
After dissolving in 5 ml, 0.5 g of a 5% palladium carbon catalyst was added, and a catalytic hydrogenation reaction was carried out for 9 hours while adding hydrogen at a hydrogen pressure of 5 to 10 kg / cm ² at room temperature according to a conventional method. After the reaction, the catalyst was filtered off, and the solvent was distilled off under reduced pressure to obtain 4.1 g of a reaction mixture. The obtained reaction mixture was subjected to distillation under reduced pressure, and a fraction having a bp of 148 to 149 ° C./3 mmHg was separated to obtain 3.3 g of a colorless oil. This is the final target product, 2- (trans-4-propylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane.

[0055]

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¹ H-NMR δ (ppm) CDCl ₃ TMS internal standard 0.8 to 2.0 (17H, m) 2.54 to 2.82 (4H, m, —CH ₂ CH ₂ —) 7.10 ７7.60 (3H, m, Ph) ¹³ C-NMR δ (ppm) CDCl ₃ TMS internal standard 112.52 (J _CF = 26.18, 4.03 Hz, Ph-3) 120.89 (J _CF = 4.03 Hz, Ph-5) 122.89 (J _CF = 271.27 Hz, Ph-CF ₃ ) 129.00 (J _CF = 32.9, 5.73 Hz, Ph-4) 131.00 (J _CF = 5.73 Hz, Ph-6) 134.40 (J _CF = 16.12 Hz, Ph-1) 160.74 (J _CF = 247.09 Hz, Ph-2) Alkyl instead of trans-4-propylcyclohexylacetyl chloride Transformers with different groups Below using 4-alkyl-cyclohexyl-acetyl chloride 2-
(Trans-4-alkylcyclohexyl) -1- (2
-Fluoro-4-trifluoromethylphenyl) ethane can be produced.

2- (trans-4-methylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 17) 2- (trans-4-ethylcyclohexyl) -1- (2 -Fluoro-4-trifluoromethylphenyl) ethane (No. 18) 2- (trans-4-butylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 19) 2 -(Trans-4-pentylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 20) 2- (trans-4-hexylcyclohexyl) -1- (2-fluoro-4- Trifluoromethylphenyl) ethane (No. 21) 2- (trans-4-heptylcyclohexyl) -1- (2-fluoro-4-trif Fluoromethylphenyl) ethane (No. 22) 2- (trans-4-octylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 23) 2- (trans-4-nonyl) Cyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 24) 2- (trans-4-decylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) Ethane (No. 25) 2- (trans-4-undecylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 26) 2- (trans-4-dodecylcyclohexyl) -1 -(2-Fluoro-4-trifluoromethylphenyl) ethane (No. 27) 2- (trans-4-tridecylcyclohexyl) -1- (2-Fluoro-4-trifluoromethylphenyl) ethane (No. 28) 2- (trans-4-tetradecylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. .29) 2- (trans-4-pentadecylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane (No. 30) Example 3 [2- (trans-4-propylcyclohexyl)- (in formula (I) compounds m = n = 1, R = C 3 ones H ₇₎ 1-[trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane production] (No 31) The reaction steps are classified into three steps: 1) Grignard reaction, 2) dehydration reaction, and 3) catalytic hydrogenation with Raney nickel. Hereinafter, details of each manufacturing process will be described.

1) Grignard reaction 1.58 g of shaved magnesium and TH
Then, 30 ml of a THF solution containing 14.6 g of 3-fluoro-4-bromobenzotrifluoride was added dropwise at room temperature over 2 hours so that the inside of the reaction system was maintained at 20 ° C., and further 3 hours at the same temperature. Aging was performed to prepare a Grignard reagent. Among the Grignard reagents thus prepared, 4- (trans-4-propylcyclohexylethyl)
25 ml of a THF solution of 12.5 g of cyclohexanone was added dropwise over 30 minutes at room temperature. After completion of the addition, the mixture was aged for 4 hours while maintaining the temperature at 40 ° C. in a warm bath. After aging, cool under ice-cooling.
After adding 100 ml of an aqueous solution of N hydrochloric acid, the solution was transferred to a separatory funnel and T
After separating the HF layer, the aqueous layer was further extracted with toluene (100 ml). After mixing the THF layer and the extraction layer,
l, 50 ml of saturated sodium bicarbonate aqueous solution and water (2
And then dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure to obtain 19.9 g of a brown oily substance.
(GC selectivity 64.8%). This is 4- (trans-4-propylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) cyclohexane-
1-Or-containing mixture. The reaction mixture was used for the next dehydration reaction step as it was.

2) Dehydration reaction In a three-necked flask equipped with a drain tube, a cooling tube, a thermometer and a stirrer, 4- (trans-4-propylcyclohexyl) -1- (2-fluoro-4-trifluoro) 18. Methylphenyl) cyclohexane-1-ol-containing mixture
9 g, 0.18 g of p-toluenesulfonic acid and 100 ml of toluene were added, and the mixture was heated and refluxed for 22 hours while stirring. After cooling to room temperature, it was transferred to a separatory funnel and water (200 m
l), washed successively with 100 ml of saturated aqueous sodium hydrogen carbonate solution and water (200 ml), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain 21.5 g of a reaction mixture. The obtained reaction mixture was subjected to distillation,
7. A fraction at a temperature of 1 ° C./1 mmHg was fractionated, and the fraction was recrystallized with a mixed solvent of ethanol-ethyl acetate to give colorless crystals.
31 g [yield from 4- (trans-4-propylcyclohexylethyl) cyclohexanone 41.9%] was obtained. This is 2- (trans-4-propylcyclohexyl) -1- [4- (2-fluoro-4-trifluoromethylphenyl) cyclohexen-1-yl] ethane.

[0060]

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¹ H-NMR δ (ppm) CDCl ₃
TMS internal standard 0.6~2.6 (28H, m) 5.99 ( 1H, m, PhC = C H -) 7.20~7.35 (3H, m, Ph) 3) contact by Raney nickel hydrogenation Dissolve 8.31 g of 2- (trans-4-propylcyclohexyl) -1- [4- (2-fluoro-4-trifluoromethylphenyl) cyclohexen-1-yl] ethane in 50 ml of ethyl acetate in a 100 ml eggplant flask, 8.0 g of developed Raney nickel was added, and a catalytic hydrogenation reaction was carried out for 21 hours while adding hydrogen at a hydrogen pressure of 5 to 10 kg / cm ² at room temperature according to a conventional method. After the reaction, the catalyst was filtered off, and the solvent was distilled off under reduced pressure to obtain 5.5 g of a colorless oil.
Further, for the purpose of separating only the trans form, recrystallization was repeated using an ethanol-ethyl acetate mixed solvent to obtain 1.5 g of colorless crystals (yield 15.6%). This is the final product 2- (trans-4-propylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl]
It is ethane.

[0062]

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¹ H-NMR δ (ppm) CDCl ₃
TMS internal standard 0.6~2.0 (30H, m) 2.54~2.92 ( 1H, m, Ph-C H -) 7.06~7.32 (3H, m, Ph) 13 C- NMR δ (ppm) CDCl ₃ TMS internal standard 112.73 (J _CF = 26.18, 3.5 Hz, P
h-3) 121.00 (J _CF = 4.0 Hz, Ph-5) 122.80 (J _CF = 271.27 Hz, -CF ₃ ) 128.00 (J _CF = 32.9, 6.0 Hz, Ph)
-4) 128.30 (J _CF = 6.0 Hz, Ph-6) 138.55 (J _CF = 16.1 Hz, Ph-1) 160.27 (J _CF = 247.10 Hz, Ph-2) GC- MS (EI) 398 (M ^<+> , 16%), 379
^{(M + -F, 4),} 355 (M + -C 3 H 7, 1), 2
59 (3), 245 (4), 232 (16), 203
(13), 191 (11), 177 (24), 145
(1), 138 (10), 125 (16), 109
(9), 97 (19), 83 (62), 69 (10
0), 55 (87), 41 (60), and 29 (1
7) 4- (trans-4-propylcyclohexylethyl)
Instead of cyclohexanone, 4-
The following 2- (trans-4-alkylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane is produced using (trans-4-alkylcyclohexylethyl) cyclohexanone. can do.

2- (trans-4-methylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 32) 2- (trans-4-ethylcyclohexyl) ) -1- [Trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 33) 2- (trans-4-butylcyclohexyl) -1- [trans-4- (2- Fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 34) 2- (trans-4-pentylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 35) 2- (trans-4-hexylcyclohexyl) -1- [trans-4 (2-Fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 36) 2- (trans-4-heptylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) Cyclohexyl] ethane (No. 37) 2- (trans-4-octylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 38) 2- (trans -4-nonylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 39) 2- (trans-4-decylcyclohexyl) -1- [trans- 4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 40) 2- (trans-4-undecylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 41) 2- (trans-4-dodecylcyclohexyl) ) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 42) 2- (trans-4-tridecylcyclohexyl) -1- [trans-4- (2 -Fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 43) 2- (trans-4-tetradecylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl Ethane (No. 44) 2- (trans-4-pentadecylcyclohexyl) -1- [ Lance-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane (No. 45) Example 4 (use example) 1,2-difluoro-4- [trans-4- (trans-4-ethylcyclohexane) Xyl) cyclohexyl] benzene 13.2% (weight, same hereafter) 1,2-difluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene 13.2% 1,2-difluoro- 4- [trans-4- (trans-4-pentylcyclohexyl) cyclohexyl] benzene 13.2% 2- (trans-4-ethylcyclohexyl) -1- [trans-4- (3,4-difluorophenyl) cyclohexyl Ethane 12.7% 2- (trans-4-propylcyclohexyl) -1- [trans -4- (3,4-difluorophenyl) cyclohexyl] ethane 6.5% 2- (trans-4-pentylcyclohexyl) -1- [trans-4- (3,4-difluorophenyl) cyclohexyl] ethane 12.7 % Trans-4-ethyl- (3,4-difluorobiphenyl-4'-yl) cyclohexane 5.7% trans-4-propyl- (3,4-difluorobiphenyl-4'-yl) cyclohexane 5. 7% trans-4-pentyl- (3,4-difluorobiphenyl-4'-yl) cyclohexane 11.4% 1-fluoro-4- [trans-4- (trans-4-ethylcyclohexyl) cyclohexyl] benzene The liquid crystal composition having a composition of 5.7% has a nematic liquid crystal-clearing point of 10%.
2.3 ° C. Although this liquid crystal composition was sealed in a TN cell (twisted nematic cell) having a cell thickness of 8.6 μm, the operating threshold voltage was 2.29 V, Δε was +4.92, Δn was 0.092, and the viscosity was 21. It was 1 cp.

Using this liquid crystal composition as a mother liquid crystal, 88 parts of the liquid crystal composition was added with 12 parts of 1-trifluoromethyl-3-fluoro-4- (trans-4-propylcyclohexyl) benzene prepared in Example 1. Has a nematic-clearing point of 77.1 ° C. and Δε of +4.8. The operating threshold voltage is 2.05 V, and Δn is 0.08
4. The viscosity was 21.8 cp. The same mother liquid crystal 88
The nematic-clearing point of the liquid crystal composition in which 12 parts of 2- (trans-4-propylcyclohexyl) -1- (2-fluoro-4-trifluoromethylphenyl) ethane prepared in Example 2 was added to 7 parts of the liquid crystal composition was 79.2. At ° C, Δε is +4.8
Met. The operating threshold voltage is 2.13V, and
n was 0.085 and viscosity was 19.5 cp.

On the other hand, 4- (trans-4-propylcyclohexyl) ethoxybenzene 21.1% (weight, the same applies hereinafter) 1,2-difluoro-4- [trans-4- (trans-4-ethylcyclohexyl) cyclohexyl] Benzene 17.5% 1,2-difluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene 17.5% 1,2-difluoro-4- [trans-4- (trans- 4-pentylcyclohexyl) cyclohexyl] benzene 17.5% 2- (trans-4-ethylcyclohexyl) -1- [trans-4- (3,4-difluorophenyl) cyclohexyl] ethane 3.0% 2- (trans -4-propylcyclohexyl) -1- [trans-4- (3,4-difluoro Phenyl) cyclohexyl] ethane 1.5% 2- (trans-4-pentylcyclohexyl) -1- [trans-4- (3,4-difluorophenyl) cyclohexyl] ethane 3.0% trans-4-ethyl- (3 , 4-Difluorobiphenyl-4'-yl) cyclohexane 2.4% trans-4-propyl- (3,4-difluorobiphenyl-4'-yl) cyclohexane 2.4% trans-4-pentyl- ( Nematic of a liquid crystal composition having a composition of 3,4-difluorobiphenyl-4'-yl) cyclohexane 4.7% 4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] toluene 9.4% Liquid crystal-clearing point is 9
4.6 ° C. The liquid crystal composition was sealed in a TN cell (twisted nematic cell) having a cell thickness of 8.7 μm, but the operating threshold voltage was 2.72 V, Δε was +3.36, Δn was 0.089, and the viscosity was 15. It was 7 cp.

Using this liquid crystal composition as a base liquid crystal, 95 parts of 2- (trans-4-propylcyclohexyl) -1- [trans-4- (2-fluoro-4-trifluoromethylphenyl) prepared in Example 3 was used. ) Cyclohexyl]
The nematic-clearing point of the liquid crystal composition containing 5 parts of ethane was 94.6 ° C., and Δ △ was +3.4. The operating threshold voltage was 2.71 V, Δn was unchanged at 0.089, and the viscosity was 19.4 cp.

Continued on the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 25/18 C09K 19/30 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. A compound of the general formula (In the above formula, R represents hydrogen or a linear or branched alkyl group having 1 to 15 carbon atoms, and m and n independently represent 0
Or a number of 1, but when m is 0, n is 0 ) 4-substituted-3-fluorotrifluoromethylbenzene derivative. 2. The 1-trifluoromethyl-3-fluoro-4- (trans-4-alkylcyclohexyl) benzene of the following formula wherein m = n = 0 in claim 1. Embedded image 3. A 2- (trans-4-alkylcyclohexyl) according to claim 1, wherein m = 1 and n = 0.
-1- (2-Fluoro-4-trifluoromethylphenyl) ethane. Embedded image 4. A 2- (trans-4-alkylcyclohexyl) -1 of the following formula wherein m = n = 1 in claim 1.
-[Trans-4- (2-fluoro-4-trifluoromethylphenyl) cyclohexyl] ethane. Embedded image 5. A liquid crystal composition comprising two or more components containing at least one compound according to claim 1.