JP2002069082A - Method for producing silacyclohexane compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preferentially produce a trans-silacyclohexane compound. SOLUTION: This method for producing the silacyclohexane compound of the general formula (4), characterized by converting a compound of the general formula (1) into a halosilacyclohexane of the general formula (2), reacting the halosilacyclohexane with an alcohol of the general formula: R'OH to convert into an alkoxysilacyclohexane of the general formula (3), equilibrating the alkoxysilacyclohexane, and then reducing the equilibrated compound. Therein, R is an alkyl, an alkoxyalkyl or a fluoroalkyl; Ar is an aryl; Q is a non- condensed polycyclic group represented by a fluorophenylcycloalkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a silacyclohexane compound used as a liquid crystal material of a liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device utilizes an optical anisotropy and a dielectric heteroelectric property of a liquid crystal material. Depending on the display mode, a TN type (twisted nematic type) and an STN type (super twisted nematic type) are used. , SBE type (super birefringent type),
DS type (dynamic scattering type), guest-host type, DAP type (deformed type of aligned phase), PD type (polymer dispersed type) and O
There are various types such as MI type (optical mode interference type).
The most common display devices are based on the Schadt-Helfrich effect and have a twisted nematic structure.

The properties required of the liquid crystal material used in these liquid crystal displays slightly vary depending on the display system, but the liquid crystal temperature range is wide, and the liquid crystal material is stable against moisture, air, light, heat, an electric field, and the like. This is commonly required in any of the display methods. Further, it is desired that the liquid crystal material has a low viscosity and provides a short address time, a low threshold voltage and a high contrast in the cell.

[0004]

In recent years, as the applications of liquid crystal displays have expanded, the characteristics required for liquid crystal materials have become increasingly severe and strict. In particular, it has been desired to further improve the characteristics of conventional liquid crystal materials, such as lowering the driving voltage, widening the temperature range corresponding to the needs for vehicles, and improving low-temperature performance.

[0005] In addition, in the production process of a conventionally known hydrocarbon liquid crystal compound, it is inevitable that a non-liquid crystal cis-isomer is produced as a by-product in addition to a trans-isomer having a liquid crystallinity. These are purified by a method such as recrystallization to separate only the trans form. On the other hand, in order to reduce the loss in the production process, the trans form may be selectively produced, but a method for selectively producing the trans form has not been reported so far.

From such a viewpoint, the inventors have developed a novel liquid crystal compound containing a silicon atom in a molecule for the purpose of improving a liquid crystal substance, and have previously filed an application. Although trans-forms are useful as these liquid crystal compounds, they are obtained as a mixture of cis-forms and trans-forms in the production stage, and it is necessary to separate the trans-form from these.

Therefore, an object of the present invention is to provide a method for preferentially producing a trans-form required for practical use when producing these novel liquid crystal compounds.

[0008]

That is, the present invention provides a compound represented by the following general formula:

Embedded image (However, Ar is a phenyl group or a tolyl group, and R is
A linear alkyl group having 10 to 10, a branched alkyl group having 3 to 8 carbon atoms, a mono- or difluoroalkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 2 to 7 carbon atoms, Q is

Embedded image (However,

Embedded image as well as

Embedded image Are each independently

Embedded image Or

Embedded image Represents

Embedded image Is

Embedded image Or

Embedded imageX represents CN, F, Cl, CF_Three, CF_TwoCl, OC
F_Three, OCHF_Two, OCF_TwoCl, OCHF Cl, (O)_m
CY = CX₁X_Two(M is 0 or 1, Y and X₁Is H, F or
Represents Cl, X_TwoRepresents F or Cl. ), O (C
H_Two)_r(CF_Two)_sX_Three(R and s are 0, 1 or 2 and
X represents a number in which (r + s) is 2, 3 or 4;_ThreeIs F
Represents Cl. ), R or OR groups, i1, i2 and
And i3 are each 0 or 1, and i1 + i2 + i3 = 1
Where j and k are 0, 1, or 2, respectively.
And j + k represents 0, 1, or 2, and Y₁And Y_Two
Each independently represents H, F or Cl;_ThreeIs H,
Represents F or a methyl group, and 1 (ell) represents 0, 1 or 2.
You. ). ) Is represented by the general formula

Embedded image (Where X 'represents F, Cl, Br or I), and then converted into a halosilacyclohexane represented by the general formula

Embedded image by reacting with an alcohol represented by R′OH (where R ′ represents a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 8 carbon atoms);

Embedded image Is converted to alkoxysilacyclohexane represented by

Embedded image Wherein the silacyclohexane compound represented by the formula is obtained.

Next, the present invention will be described in more detail.

The present invention relates to a method for preferentially producing a trans-form required for practical use in producing these novel liquid crystal compounds. Such a highly stereoselective reaction is impossible with conventional hydrocarbon-based liquid crystal compounds,
The present invention can be achieved by a novel liquid crystal compound containing a silicon atom in a molecule, which was previously filed by the present inventors. As a result, the yield of the entire production process is improved, and the process is more economical than conventional hydrocarbon-based liquid crystal compounds.

Specifically, as shown in the following reaction formula, from a phenylsilacyclohexane compound,
A halosilacyclohexane compound can be obtained by a reaction with an electrophile. It is preferable to use 1 to 2 equivalents of the electrophile with respect to silacyclohexane. This reaction is 0
The temperature is preferably from 80 to 80 ° C, and the temperature is preferably from 10 to 40 ° C.

Embedded image

Examples of the electrophilic reagent include halogen, hydrogen halide, metal halide, sulfonic acid derivative, acid halide, and alkyl halide. In particular, iodine, bromine, chlorine, iodine monochloride, hydrogen chloride, hydrogen bromide, hydrogen iodide, mercury (II) chloride, trimethylsilyl chlorosulfonate, acetyl chloride, acetyl bromide,
Preferred examples include benzoyl chloride and t-butyl chloride. In order to increase the reaction rate, Lewis acids such as aluminum chloride, zinc chloride, titanium tetrachloride, and boron trifluoride may be added or light irradiation (visible light, ultraviolet light) may be performed.

At this time, the configuration of the alkyl group is equilibrated on the silicon atom, and Q and the alkyl group have a more stable trans configuration with respect to the silacyclohexane ring.

Embedded image

In general, it is known that reduction of chlorosilane proceeds by steric inversion (“The Chemis”).
try of Organic Silicon Co
mounds Part 1 "Chapter 4, Saul P
atai and ZviRappport; Joh
n Wiley & Sons (1989)).

Embedded image

Accordingly, when the halosilacyclohexane compound is reduced using a reducing agent described later, the reduction proceeds by steric inversion, and the yield of the desired trans form is reduced.

Embedded image

[0016] Therefore, by passing through an alkoxysilacyclohexane compound that can be reduced by steric retention, the configuration of the alkyl group on the silicon atom is equilibrated, and after the ratio of the trans form is increased, reduction is carried out. The inventors have found that the trans form can be obtained with good yield, and have completed the present invention.

More specifically, the required alkoxysilacyclohexane compound can be obtained by reacting a halosilacyclohexane compound with an alcohol.

[0018]

Embedded image

At this time, the configuration of the alkyl group is equilibrated on the silicon atom, so that Q and the alkyl group have a more stable trans configuration.

[0020]

Embedded image

In general, reduction of alkoxysilane is known to proceed by steric retention (“The Chem”).
istry of Organic Silicon
Compounds Part 1 "Chapter 4, Saul
Patai and Zvi Rapport;
John Wiley & Sons (1989)).

[0022]

Embedded image

Accordingly, when the alkoxysilacyclohexane compound is reduced using a reducing agent described later, the reduction proceeds due to steric retention, and the desired trans form can be obtained in good yield.

Embedded image

More specifically, the alcohol used in the reaction of [Chemical Formula 31] is preferably a linear or branched alkyl alcohol having 1 to 10 carbon atoms. At this time, an amine such as triethylamine or urea, or an epoxy such as propylene oxide may be added to neutralize the generated hydrogen halide.

As shown in [Formula 32], equilibration occurs when converting the halosilacyclohexane compound to the alkoxysilacyclohexane compound. This reaction is preferably performed at 0 to 80 ° C. for 0.1 to 5 hours. In addition, heating at 30 to 80 ° C., 1 to 5 equivalents to lower alcohol halosilacyclohexane compound having 1 to 5 carbon atoms such as methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, etc. Use or addition of sodium methylate or sodium ethylate metal alcoholate can promote equilibration. Further, these operations can be combined. At this time, as the solvent, ethers such as diethyl ether, THF, dioxane, the above-mentioned alcohols, benzene,
It is preferable to use hydrocarbons such as toluene and hexane.

Reagents used for reduction of the equilibrated alkoxysilacyclohexane compound include metal hydrides such as sodium hydride, calcium hydride, trialkylsilanes, borane, dialkylaluminum, lithium aluminum hydride, borohydride Complex hydride compounds such as sodium, lithium borohydride, potassium borohydride, tributylammonium borohydride (Co
hydride and their substituted hydride compounds, ie, lithium trialkoxyaluminum hydride, sodium di (methoxyethoxy) aluminum hydride, lithium triethylborohydride,
Sodium cyanoborohydride and the like can be mentioned. These reducing reagents are used in an amount of 1 to 5 equivalents relative to alkoxysilacyclohexane, and the reduction
-100 ° C, more preferably 20-70 ° C. Such a reduction reaction is carried out in a solution of diethyl ether, THF, dioxane, toluene, xylene, hexane, isooctane and the like.

As described above, the compound produced according to the method of the present invention is purified to a purity required for practical use by a conventional method such as recrystallization or chromatography to obtain the desired trans-form of the silacyclohexane type liquid crystal compound. Obtainable.

According to the method of the present invention, the selectivity of the trans-isomer of the silicon-containing liquid crystal compound can be increased as compared with the known production process of the hydrocarbon liquid crystal compound. Therefore, it is very significant that the loss due to the by-product of the cis-form in the manufacturing process is reduced.

[0029]

The present invention will be described below in more detail with reference to specific examples.

[Production Example 1] 4- (trans-4- (2-
Production of (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-silacyclohexane 47.0 g of 3,4-difluorobenzyltriphenylphosphonium bromide and tetrahydrofuran (hereinafter referred to as “THF”) 12.0 g of potassium t-butoxide was added to 200 ml of a mixture to prepare a light-colored ylide solution, and 4- (4-n-pentyl-4-phenyl-4-silacyclohexyl) cyclohexanecarbamate was added to this solution. 35.0 g of aldehyde were added in 50 ml of THF. After stirring at room temperature for 2 hours, the mixture was poured into ice water and extracted with ethyl acetate. 100 ml of n-hexane was added to the residue obtained by washing with ordinary brine, drying and concentration, the resulting triphenylphosphine oxide crystals were filtered off, and the filtrate was concentrated. The residue was purified by silica gel chromatography to give 4- (trans-4- (2- (3,4-difluorophenyl) ethenyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-silacyclohexane 41.7.
g was obtained. IR (liquid film) νmax: 2920, 2855, 159
5,1515,1425,1290,1110,96
0,800cm ^-1

The obtained 4- (trans-4- (2-
40.0 g of (3,4-difluorophenyl) ethenyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-silacyclohexane was dissolved in 200 ml of ethyl acetate, and hydrogenated at 0.1 MPa using 200 mg of platinum oxide as a catalyst. did. After the theoretical amount of hydrogen has been consumed, the catalyst is filtered off and the filtrate is concentrated to give 4- (trans-4- (2-
40.2 g of (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-silacyclohexane was obtained. IR (liquid film) νmax: 2920, 2855, 160
5,1518,1280,1110,853,810c
m ^-1

Example 1 trans-4- (trans-4- (2- (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-
Production of pentyl-1-silacyclohexane 4- (trans-4- (2-) obtained in Production Example 1
(3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-silacyclohexane 40.0 g at room temperature, 1.0 mol / l (liter) iodine monochloride 100 ml dichloromethane solution
Was added and stirred for 1 hour to obtain a cis-trans isomer mixture. GC-MS (70 eV) (m / z) ⁺ cis form: 426 (M ⁺ ), 355 (M ⁺ -C ₅ H ₁₁ ), trans form: 426 (M ⁺ ), 355 (M ⁺ -C ₅ H ₁₁₎ )

Subsequently, a mixture of 4.0 g of methanol and 11.0 g of triethylamine was added to this solution at room temperature.
The mixture was further stirred under reflux for 1 hour. The resulting 4- (trans-4
-(2- (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-pentyl-1-methoxy-1-
When the mixture of cis-trans isomers of silacyclohexane was quantified by gas chromatography, the cis-form (retention time: 12.02 minutes) and the trans-form (retention time: 12.
28 min) was 10:90. (Measurement conditions: 58 manufactured by Hewlett-Packard)
90-II, capillary column: Hewlett-Pa
The measurement was carried out under the same conditions as in Ultra-20.25φ × 30 m manufactured by CARD. (Temperature conditions: temperature is raised from 200 ° C. to 300 ° C. at 10 ° C./min, hereinafter abbreviated as “200 ° C. + 10 ° C./min→300° C.”) GC-MS (70 eV) (m / z) ⁺ cis-form: 422 (M ⁺ ), 351 (M ⁺ -C ₅ H ₁₁ ) Trans form: 422 (M ⁺ ), 351 (M ⁺ -C ₅ H ₁₁ )

Next, after concentrating the reaction mixture, 200 ml of hexane was added to precipitate by-product triethylamine hydrochloride, which was filtered off, and the filtrate was concentrated to give 4-ethylamine.
(Trans-4- (2- (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-pentyl-1
34.6 g of -methoxy-1-silacyclohexane were obtained. This was dissolved in 100 ml of THF, and added to a solution of 10.0 g of lithium aluminum hydride in 100 ml of THF. After the reaction mixture was stirred under reflux for 1 hour, the target cis-trans isomer mixture was quantified by gas chromatography under the above conditions.
35 minutes) and the trans form (retention time: 11.61 minutes) were 12:88. The reaction mixture was treated with 5% hydrochloric acid 200
The mixture was poured into ml and extracted with ethyl acetate. After washing with ordinary brine, drying and concentration, purification was performed by silica gel chromatography to obtain 28.9 g (yield: 86.3%) of the desired product. This compound exhibited nematic liquid crystallinity between 7.6 and 69.7 ° C., and was found to be very useful as a liquid crystal material. IR (liquid film) νmax: 2920, 2852, 209
8,1520,1286,1211,1119,88
7,816 cm ^-1

[Comparative Example 1] 4-Compound obtained in [Production Example 1]
(Trans-4- (2- (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-pentyl-1
To 40.0 g of -phenyl-1-silacyclohexane at room temperature, 100 ml of a 1.0 mol / l (liter) solution of iodine monochloride in dichloromethane was added, and the mixture was stirred for 1 hour to obtain a cis-trans isomer mixture. When this was quantified by gas chromatography under the above conditions, the cis form (retention time: 12.62 minutes) and the trans form (retention time: 13.
05 min) was 83:17. After concentrating the reaction mixture, the residue was dissolved in 100 ml of THF,
Of lithium aluminum hydride in THF10
0 ml was added to the solution. After stirring the reaction mixture for 30 minutes,
The ratio of the cis-trans isomer was 83:17 when the target cis-trans isomer mixture was quantified by gas chromatography under the above conditions. 5% reaction mixture
The mixture was poured into 200 ml of hydrochloric acid and extracted with ethyl acetate. After washing with ordinary brine, drying and concentration, the resultant is purified by silica gel chromatography to obtain 5.4 g of the desired product (yield 16.1).
%).

[Production Example 2] 4- (trans-4- (3,4-difluorophenyl)
Cyclohexyl) -1-n-pentyl-1-phenyl-
Production of 1-silacyclohexane 19.3 g of 3,4-difluorobromobenzene was dropped into a mixture of 2.55 g of magnesium and 50 ml of THF, and refluxed for 3 hours to obtain a Grignard reagent. This is 4
-(4-n-pentyl-4-phenyl-4-silacyclohexyl) cyclohexanone 34.0 g of THF 50 m
1 solution was added. After refluxing for 2 hours, the reaction mixture was cooled to room temperature, poured into an aqueous ammonium chloride solution, and extracted with benzene. 1 g of p-toluenesulfonic acid was added to this benzene solution.
Was added, and the generated water was separated and removed while refluxing. When no more water distilled, the mixture was cooled to room temperature. Next, the reaction mixture was poured into an aqueous sodium hydrogen carbonate solution, washed with ordinary brine, dried and concentrated, and the residue was purified by silica gel chromatography to give 4- (4- (3,4
-Difluorophenyl) -3-cyclohexenyl) -1
38.0 g of -n-pentyl-1-phenyl-1-silacyclohexane were obtained. This was dissolved in 200 ml of ethyl acetate, and 0.2 mg of palladium-carbon was used as a catalyst.
Hydrogenation was performed at 5 MPa. After the theoretical amount of hydrogen has been consumed, the catalyst is filtered off and the filtrate is concentrated to give 4- (trans-4
-(3,4-difluorophenyl) cyclohexyl)-
38.2 g of 1-n-pentyl-1-phenyl-1-silacyclohexane was obtained. IR (liquid film) νmax: 2920, 2855, 160
3,1517,1422,1274,1110,86
8,812 cm ^-1

Example 2 trans- (4- (trans-4- (3,4-difluorophenyl) cyclohexyl))-1-n-pentyl-
Production of 1-silacyclohexane 4- (trans-4- (3,4) obtained in [Production Example 2]
-Difluorophenyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-silacyclohexane 38.
To 0 g, 100 ml of a 1.0 mol / l (liter) solution of iodine monochloride in dichloromethane was added at room temperature, followed by stirring for 1 hour to obtain a cis-trans isomer mixture. GC-MS (70 eV) (m / z) ⁺ cis form: 398 (M ⁺ ), 327 (M ⁺ -C ₅ H ₁₁ ) Trans form: 398 (M ⁺ ), 327 (M ⁺ -C ₅ H ₁₁ )

Subsequently, a mixture of 5.0 g of ethanol and 6.0 g of urea was added to this solution at room temperature, and the mixture was further stirred under reflux for 1 hour. The obtained cis-trans isomer mixture of 4- (trans-4- (3,4-difluorophenyl) cyclohexyl) -1-n-pentyl-1-ethoxy-1-silacyclohexane was quantified by gas chromatography. The ratio between the cis form (retention time: 10.65 minutes) and the trans form (retention time: 10.72 minutes) was 10:90. GC-MS (70 eV) (m / z) ⁺ cis form: 408 (M ⁺ ), 337 (M ⁺ -C ₅ H ₁₁ ) Trans form: 408 (M ⁺ ), 337 (M ⁺ -C ₅ H ₁₁ )

Next, after concentrating this reaction mixture, 200 ml of hexane was added to separate by-produced urea hydrochloride.
The residue is concentrated to give 4- (trans-4- (3,4-difluorophenyl) cyclohexyl) -1-n-pentyl-
33.8 g of 1-ethoxy-1-silacyclohexane was obtained. This was dissolved in 100 ml of THF, and added to a solution of 10.0 g of lithium aluminum hydride in 100 ml of THF. After the reaction mixture was stirred under reflux for 1 hour, the target cis-trans isomer mixture was quantified by gas chromatography under the above-mentioned conditions. As a result, the cis-isomer (retention time: 9.5) was obtained.
6 minutes) and the trans form (retention time: 9.66 minutes) were 11:89. 200 ml of 5% hydrochloric acid
And extracted with ethyl acetate. After washing with ordinary brine, drying and concentration, purification was performed by silica gel chromatography to obtain 25.2 g (yield: 80.2%) of the desired product. This product exhibited nematic liquid crystallinity between 14.3 and 71.6 ° C., and was found to be very useful as a liquid crystal material. IR (liquid film) νmax: 2923, 2845, 209
2,1608,1520,1296,1213,111
3,891,825,808cm ^-1

[Comparative Example 2] 4-Compound obtained in [Production Example 2]
(Trans-4- (3,4-difluorophenyl) cyclohexyl) -1-n-pentyl-1-phenyl-1-
1.0 mol at room temperature in 33.0 g of silacyclohexane
/ L (liter) dichloromethane solution of iodine monochloride 1
After adding 00 ml, the mixture was stirred for 1 hour to obtain a cis-trans isomer mixture. When this was quantified by gas chromatography under the above conditions, the cis form (retention time: 10.83)
Min) to the trans form (retention time: 11.17 minutes) was 84:16. After concentrating the reaction mixture, the residue was dissolved in 100 ml of THF and added at 0 ° C. to a solution of 10.0 g of lithium aluminum hydride in 100 ml of THF. After the reaction mixture was stirred for 30 minutes, the mixture of cis-trans isomers as a target product was quantified by gas chromatography under the above conditions.
4:16. The reaction mixture was poured into 200 ml of 5% hydrochloric acid and extracted with ethyl acetate. Wash with normal brine,
After drying and concentration, the residue was purified by silica gel chromatography to obtain 3.9 g (yield 12.4%) of the desired product.

[Production Example 3] 4- (p-fluorophenyl) -1-n-heptyl-1
Preparation of -Phenyl-1-silacyclohexane 17.5 g of p-fluorobromobenzene was dropped into a mixture of 2.55 g of magnesium and 50 ml of THF, and 3
Reflux for an hour to obtain a Grignard reagent. 4-n-
Heptyl-4-phenyl-4-silacyclohexanone 2
8.0 g of a 50 ml solution of THF was added. After refluxing for 2 hours, the reaction mixture was cooled to room temperature, poured into an aqueous ammonium chloride solution, and extracted with benzene. Add p to this benzene solution
-1 g of toluenesulfonic acid was added, and the generated water was separated and removed while refluxing. When no more water distilled, the mixture was cooled to room temperature. The reaction mixture was poured into aqueous sodium hydrogen carbonate solution, washed with normal brine, dried and concentrated, and the residue was purified by silica gel chromatography.
4- (p-fluorophenyl) -1-n-heptyl-1
-Phenyl-1-sila-3-cyclohexene 33.0 g
I got This was dissolved in 200 ml of ethanol, and hydrogenated at 0.5 MPa using 200 mg of palladium-carbon as a catalyst. After the theoretical amount of hydrogen has been consumed, the catalyst is filtered off and the filtrate is concentrated to give 4- (p-fluorophenyl) -1.
33.2 g of -n-heptyl-1-phenyl-1-silacyclohexane was obtained.

Example 3 Production of trans-4- (p-fluorophenyl) -1-n-heptyl-1-silacyclohexane 4- (p-fluorophenyl) obtained in [Production Example 3]
To 33.0 g of -1-n-heptyl-1-phenyl-1-silacyclohexane, 100 ml of a 1.0 mol / l (liter) solution of iodine monochloride in dichloromethane was added at room temperature, and the mixture was stirred for 1 hour. A mixture was obtained. GC-MS (70 eV) (m / z) ⁺ cis form: 326 (M ⁺ ), 298 (M ⁺ -C ₂ H ₄ ), 29
7 (M ⁺ -C ₇ H ₁₅ ) trans form: 326 (M ⁺ ), 298 (M ⁺ -C ₂ H ₄ ),
297 (M ⁺ -C ₇ H ₁₅ )

Subsequently, a mixture of 7.0 g of isopropyl alcohol and 11.0 g of triethylamine was added to this solution at room temperature, and the mixture was further stirred under reflux for 1 hour. The obtained 4-
When a mixture of cis-trans isomers of (p-fluorophenyl) -1-n-heptyl-1-isopropoxy-1-silacyclohexane was quantified by gas chromatography, a cis-isomer (retention time: 6.64 minutes) was obtained. The ratio of the trans form (retention time: 6.74 minutes) was 14:86. GC-MS (70 eV) (m / z) ⁺ cis form: 350 (M ⁺ ), 322 (M ⁺ -C ₂ H ₄ ), 25
1 (M ⁺ -C ₇ H ₁₅ ) trans form: 350 (M ⁺ ), 322 (M ⁺ -C ₂ H ₄ ),
251 (M ⁺ -C ₇ H ₁₅ )

Next, after concentrating the reaction mixture, 200 ml of hexane was added to precipitate by-product triethylamine hydrochloride, which was separated by filtration, and the filtrate was concentrated to give 4- (p
-Fluorophenyl) -1-n-heptyl-1-isopropoxy-1-silacyclohexane 28.2 g were obtained.
This was dissolved in 100 ml of THF, and added to a solution of 10.9 g of lithium aluminum hydride in 100 ml of THF.
After the reaction mixture was stirred under reflux for 2 hours, the target cis-trans isomer mixture was quantified by gas chromatography under the above-mentioned conditions. As a result, the cis-isomer (retention time: 5.65) was obtained.
Min) to the trans form (retention time: 5.71 minutes) is 1
5:85. The reaction mixture was poured into 200 ml of 5% hydrochloric acid and extracted with ethyl acetate. Wash with normal brine,
After drying and concentration, the residue was purified by silica gel chromatography to obtain 19.0 g (yield: 72.6%) of the desired product. IR (liquid film) νmax: 2920, 2100, 151
0,1458,1408,1228,985,887,
820 cm ^{-1 13} C-NMR (67.5 MHz, CDCl ₃ ): 10.
56 (s), 12.13 (s), 14.11 (s), 2
2.74 (s), 24.44 (s), 29.08
(S), 31.85 (s), 33.19 (s), 33.
45 (s), 46.92 (s), 114.90 (d),
127.89 (d), 144.31 (d), 161.0
9 (d) ppm

[Comparative Example 3] 4-Compound obtained in [Production Example 3]
To 33.0 g of (p-fluorophenyl) -1-n-heptyl-1-phenyl-1-silacyclohexane, 100 ml of a 1.0 mol / l (liter) solution of iodine monochloride in dichloromethane was added at room temperature, followed by stirring for 1 hour. , A mixture of cis-trans isomers. When this was quantified by gas chromatography under the above conditions, the cis form (retention time: 6.50 minutes) and the trans form (retention time: 6.78)
Min) was 83:17. After concentrating the reaction mixture, the residue was dissolved in 100 ml of THF, and at 0 ° C. 10.0 g of lithium aluminum hydride in 100 ml of THF was added.
1 solution. After stirring the reaction mixture for 30 minutes, the target cis-trans isomer mixture was quantified by gas chromatography under the above conditions, and the ratio of the cis-isomer to the trans-isomer was 80:20. The reaction mixture was poured into 200 ml of 5% hydrochloric acid and extracted with ethyl acetate. After washing with ordinary brine, drying and concentration, purification by silica gel chromatography gave 5.0 g of the desired product (19.2% yield).
I got

The following compounds were prepared in the same manner as in Example 1.

Example 4 trans-4- (2- (trans-4- (3,4-difluorophenyl) cyclohexyl) ethyl) -1-n-
Preparation of propyl-1-silacyclohexane 4- (2-trans-4- (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-propyl-1
-Phenyl-1-silacyclohexane. Retention time of gas chromatography cis form: 9.82 minutes, trans form: 9.92 minutes Temperature: 200 ° C. + 10 ° C./min→300° C. Ratio of cis form and trans form: 15:85 Yield: 73.1% Liquid crystal temperature range: C11.2N63.5I IR (liquid film) νmax: 2922, 2850, 210
0,1909,1518,1288,887,815c
m ^-1

Comparative Example 4 In the same manner as in Comparative Example 1, 4- (2-trans-4- (3,4-difluorophenyl) ethyl) cyclohexyl) -1-n-propyl-1
[Example 4] from -phenyl-1-silacyclohexane
Was produced. The ratio of cis to trans is 8
0:20, and the yield was as low as 11.5%.

Example 5 Preparation of 4 '-(trans-4-n-propyl-4-silacyclohexyl) -4-fluorobiphenyl 4'-(4-n-propyl-4-phenyl-4-silacyclohexyl ) -4-Fluorobiphenyl. Retention time of gas chromatography Cis form: 8.64 minutes, trans form: 8.78 minutes Temperature: 200 ° C. + 10 ° C./min→300° C. Ratio of cis form and trans form: 16:84 Yield: 71.6% Liquid crystal temperature range: C80.2N119.3I IR (liquid film) νmax: 2918, 2854, 208
7, 1604, 1497, 1238, 987, 889,
816 cm ^-1

Comparative Example 5 The purpose of [Example 5] from 4 '-(4-n-propyl-4-phenyl-4-silacyclohexyl) -4-fluorobiphenyl in the same manner as in [Comparative Example 1]. Was manufactured. The ratio of the cis-isomer to the trans-isomer was 79:21, and the yield was as low as 13.5%.

Example 6 Preparation of trans-4- (2- (p-ethoxyphenyl) ethyl) -1-n-pentyl-1-silacyclohexane 4- (2- (p-ethoxyphenyl) ethyl-1 -N-
(Pentyl-1-phenyl) silacyclohexane. Retention time of gas chromatography: cis form: 7.98 minutes, trans form: 8.10 minutes Temperature: 200 ° C. + 10 ° C./min→300° C. Ratio of cis form to trans form: 20:80 Yield: 68.9% Liquid crystal temperature range: C0.2 (N) -1.7I IR (liquid film) νmax: 2918, 2852, 209
8, 1612, 1512, 1244, 1051, 88
7,822 cm ^-1

[Comparative Example 6] In the same manner as in [Comparative Example 1], 4- (2- (p-ethoxyphenyl) ethyl-1-n-
The target product of [Example 6] was produced from pentyl-1-phenyl) silacyclohexane. The ratio of the cis-form to the trans-form was 81:19, and the yield was as low as 12.6%.

Example 7 trans, trans-2-fluoro-4- (4-n-pentyl-4-silacyclohexyl) -4 '-(4-n-
Preparation of propylcyclohexyl) biphenyl 2-fluoro-4- (4-n-pentyl-4-phenyl-4-silacyclohexyl) -4 ′-(trans-4-
n-Propylcyclohexyl) biphenyl. Retention time of gas chromatography: cis form: 19.55 minutes, trans form: 20.25 minutes Temperature: constant at 300 ° C. Ratio of cis form and trans form: 11:89 Yield: 74.6% Liquid crystal temperature range: C79. 0S95.0N247.0I IR (liquid film) νmax: 2920, 2848, 209
8, 1493, 1404, 1194, 987, 887,
812 cm ^-1

[Comparative Example 7] In the same manner as in [Comparative Example 1], 2-fluoro-4- (4-n-pentyl-4-phenyl-4-silacyclohexyl) -4 '-(trans-4-
The target product of [Example 7] was produced from (n-propylcyclohexyl) biphenyl. The ratio of the cis-isomer to the trans-isomer was 87:13, and the yield was as low as 9.6%.

Example 8 Preparation of trans, trans-4- (4-methoxycyclohexyl) -1-n-propyl-1-silacyclohexane 4- (trans-4-methoxycyclohexyl) -1-
Obtained from n-propyl-1-phenyl-1-silacyclohexane. Retention time of gas chromatography cis form: 4.33 minutes, trans form: 4.47 minutes Temperature: 200 ° C. + 10 ° C./min→300° C. Ratio of cis form and trans form: 19:81 Yield: 69.9% Liquid crystal temperature range: C <−60N−40.0I IR (liquid film) νmax: 2928, 2856, 282
0, 2098, 1452, 1103, 989, 887,
843,820 cm ^-1

Comparative Example 8 In the same manner as in Comparative Example 1, 4- (trans-4-methoxycyclohexyl) -1- was used.
The target product of Example 8 was produced from n-propyl-1-phenyl-1-silacyclohexane. The ratio of the cis-isomer to the trans-isomer was 83:17, and the yield was as low as 10.1%.

Example 9 Production of 4- (2- (trans-4-n-pentyl-4-silacyclohexyl) ethyl) -3 ', 4'-difluorobiphenyl 4- (2- (4-n- Pentyl-4-phenyl-4-silacyclohexyl) ethyl) -3 ′, 4′-difluorobiphenyl. Retention time of gas chromatography: cis form: 5.43 minutes, trans form: 5.53 minutes Temperature: constant at 300 ° C. Ratio of cis form and trans form: 18:82 Yield: 70.2% Liquid crystal temperature range: C38. 6N58.2I IR (liquid film) νmax: 2920, 2850, 210
0,1605,1504,1311,1267,814
cm ^-1

Comparative Example 9 4- (2- (4-n-pentyl-4-phenyl-4-silacyclohexyl) ethyl) -3 ′, 4′-difluorobiphenyl was prepared in the same manner as in Comparative Example 1. To produce the target product of [Example 9]. The ratio between the cis form and the trans form is 80:20, and the yield is 1
It was found to be unfavorable, as low as 1.4%.

Example 10 trans, trans-4- (4- (4-n-propyl-
4-silacyclohexyl) cyclohexyl) -3 ′,
Production of 4'-difluorobiphenyl 4- (trans-4- (4-n-propyl-4-phenyl-4-silacyclohexyl) cyclohexyl)-
Obtained from 3 ', 4'-difluorobiphenyl. Retention time of gas chromatography: cis isomer: 21.23 minutes, trans isomer: 21.59 minutes Temperature: constant at 300 ° C. Ratio of cis isomer to trans isomer: 14:86 Yield: 71.1% Liquid crystal temperature range: C82. 7S107.5N229.1I IR (liquid film) νmax: 2916, 2848, 210
4,1533,1506,1279,985,889,
845,814cm ^-1

[Comparative Example 10] In the same manner as in [Comparative Example 1], 4- (trans-4- (4-n-propyl-4-phenyl-4-silacyclohexyl) cyclohexyl)-
From 3 ′, 4′-difluorobiphenyl [Example 10]
Was produced. The ratio of cis to trans is 8
The ratio was 5:15, and the yield was as low as 8.9%.

Example 11 Preparation of 4- (trans-4-n-pentyl-4-silacyclohexyl) -2 ′, 4 ″ -difluoroterphenyl 4- (4-n-pentyl-4-phenyl-4 -Silacyclohexyl) -2 ', 4 "-difluoroterphenyl. Retention time of gas chromatography: cis form: 11.78 minutes, trans form: 12.67 minutes Temperature: constant at 300 ° C. Ratio of cis form and trans form: 10:90 Yield: 73.1% Liquid crystal temperature range: C87. 8S135.0N250.3I IR (KBr Disc) νmax: 2918,284
6,2106,1487,1223,887,816c
m ^-1

[Comparative Example 11] In the same manner as in [Comparative Example 1], 4- (4-n-pentyl-4-phenyl-4-silacyclohexyl) -2 ′, 4 ″ -difluoroterphenyl was used to prepare [Example. [11] The ratio of the cis-isomer to the trans-isomer was 89:11, and the yield was as low as 7.3%, which was unfavorable.

Example 12 Preparation of trans-4- (4-n-pentyl-4-silacyclohexyl) -2-fluoro-4 '-(2- (3,4-difluorophenyl) ethyl) biphenyl 4- (4-n-pentyl-4-phenyl-4-silacyclohexyl) -2-fluoro-4 ′-(2- (3,4-
Obtained from difluorophenyl) ethyl) biphenyl. Retention time of gas chromatography Cis form: 15.89 minutes, trans form: 17.18 minutes Temperature: constant at 300 ° C. Ratio of cis form and trans form: 11:89 Yield: 72.8% Liquid crystal temperature range: C49. 5 (SA) 50.6N150.
5I IR (KBr Disc) νmax: 2920, 210
2,1518,1491,1404,1290,128
6,1120,889,818cm ^-1

[Comparative Example 12] In the same manner as in [Comparative Example 1], 4- (4-n-pentyl-4-phenyl-4-silacyclohexyl) -2-fluoro-4 '-(2- (3,3 4
The target product of [Example 12] was produced from -difluorophenyl) ethyl) biphenyl. The ratio of the cis-isomer to the trans-isomer was 89:11, and the yield was as low as 7.5%.

Example 13 Preparation of trans, trans-4- (2- (4- (4-n-propyl-4-silacyclohexyl) cyclohexyl) ethyl) -4'-chloro-3'-fluorobiphenyl -(2- (trans-4- (4-n-propyl-4-
Phenyl-4-silacyclohexyl) cyclohexyl)
Ethyl) -4'-chloro-3'-fluorobiphenyl. Retention time of gas chromatography: cis form: 17.35 minutes, trans form: 18.39 minutes Temperature: constant at 300 ° C. Ratio of cis form to trans form: 14:86 Yield: 70.1% Liquid crystal temperature range: C63. 3N208.0I IR (liquid film) νmax: 2920, 2850, 209
6,1560,1481,1200,1070,98
2,889,845,805cm ^-1

[Comparative Example 13] In the same manner as in [Comparative Example 1], 4- (2- (trans-4- (4-n-propyl-4)
The target compound of [Example 13] was produced from -phenyl-4-silacyclohexyl) cyclohexyl) ethyl) -4'-chloro-3'-fluorobiphenyl. The ratio between the cis form and the trans form is 84:16, and the yield is 10.4%.
It was found to be low, which was not preferable.

Example 14 Production of 4- (2- (trans- (4-n-pentyl-4-silacyclohexyl)) ethyl) -4 ′-(4-fluorophenyl) biphenyl 4- (2- ( 4-n-pentyl-4-phenyl-4-silacyclohexyl) ethyl) -4 '-(4-fluorophenyl) biphenyl. Retention time of gas chromatography: cis form: 18.91 minutes, trans form: 19.45 minutes Temperature: constant at 300 ° C. Ratio of cis form and trans form: 17:83 Yield: 71.6%

[Comparative Example 14] In the same manner as in [Comparative Example 1], 4- (2- (4-n-pentyl-4-phenyl-4-phenyl-4-) was used.
The target product of [Example 14] was produced from (silacyclohexyl) ethyl) -4 '-(4-fluorophenyl) biphenyl. The ratio of the cis-isomer to the trans-isomer was 80:20, and the yield was as low as 14.2%.

Example 15 4- (trans-4- (trans-4-n-pentyl-
Preparation of 4-silacyclohexyl) cyclohexyl) -1-trifluoromethoxybenzene 4- (trans-4- (4-N-pentyl-4-phenyl-4-silacyclohexyl) cyclohexyl) -1-
Obtained from trifluoromethoxybenzene. Retention time of gas chromatography cis form: 9.28 minutes, trans form: 9.58 minutes Temperature: 200 ° C. + 10 ° C./min→300° C. Ratio of cis form and trans form: 18:82 Yield: 68.8% Liquid crystal temperature range: C37.7N80.1I IR (KBr Disc) νmax: 2924,285
4,2102,1510,1267,1223,119
4,1159,987,818cm ^-1

[Comparative Example 15] 4- (trans-4- (4-N-pentyl-4-phenyl-4-silacyclohexyl) cyclohexyl) -1 was prepared in the same manner as in [Comparative Example 1].
-The intended product of [Example 15] was produced from trifluoromethoxybenzene. The ratio of cis to trans is 82:
18, and the yield was as low as 13.9%.

[0071]

As described above, according to the present invention, among the silacyclohexane compounds having a silicon atom in the molecule, it has become possible to preferentially produce a trans-isomer having liquid crystallinity. The thus obtained silacyclohexane liquid crystal compound is very useful as a material for a liquid crystal display device or the like.

Continuing from the front page (72) Inventor Takeshi Kaneo 28, Nishifukushima, Nishifukushima-mura, Nakakushiro-gun, Niigata Prefecture Inside the Synthetic Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Tatsushi Kaneko, Kushiro-mura, Nakakushiro-gun, Niigata Shin-Etsu Chemical Co., Ltd., Synthetic Technology Research Laboratories, 28-28 Nishifukushima, Japan (72) Inventor Mutsumi Nakajima, 28-28 Nishi-Fukushima, Oku-ku, Niigata Pref. (Reference) 4H027 BD02 BD04 BE04 DJ01 DJ03 DJ04 4H049 VN01 VP01 VQ84 VS84 VT03 VT05 VT19 VU25 VV03 VV16

Claims (1)

[Claims] 1. A compound of the general formula(However, Ar is a phenyl group or a tolyl group, and R is
A straight-chain alkyl group having 10 to 10 carbon atoms and a branched chain alkyl group having 3 to 8 carbon atoms.
Alkyl group, mono- or difluoroalkyl having 1 to 10 carbon atoms
Or an alkoxyalkyl group having 2 to 7 carbon atoms, Q is(However,AndAre independently of each otherOrAnd representsIsOrX represents CN, F, Cl, CF_Three, CF_TwoCl, OC
F_Three, OCHF_Two, OCF_TwoCl, OCHF Cl, (O)_m
CY = CX₁X_Two(M is 0 or 1, Y and X₁Is H, F or
Represents Cl, X_TwoRepresents F or Cl. ), O (C
H_Two)_r(CF_Two)_sX_Three(R and s are 0, 1 or 2 and
X represents a number in which (r + s) is 2, 3 or 4;_ThreeIs F
Represents Cl. ), R or OR groups, i1, i2 and
And i3 are each 0 or 1, and i1 + i2 + i3 = 1
Where j and k are 0, 1, or 2, respectively.
And j + k represents 0, 1, or 2, and Y₁And Y_Two
Each independently represents H, F or Cl;_ThreeIs H,
Represents F or a methyl group, and 1 (ell) represents 0, 1 or 2.
You. ). ) Is converted to a compound represented by the general formula:(However, X 'represents F, Cl, Br or I.)
After conversion to halosilacyclohexane, R'OH (where R 'is a linear alkyl group having 1 to 10 carbon atoms or carbon)
Represents a branched alkyl group having a prime number of 3 to 8. Al)
Reacting with Cole to form the general formulaIs converted to alkoxysilacyclohexane represented by
After equilibration, reduction is performed to obtain the general formulaCharacterized by obtaining a silacyclohexane compound represented by
A method for producing a silacyclohexane compound.