JP2001163834A - Antiferroelectric liquid crystal compound having difluoromethylene bond and liquid crystal composition containing the same - Google Patents

Abstract

[PROBLEMS] To provide an excellent liquid crystal material for a component of an antiferroelectric liquid crystal composition. A compound having a difluoromethylene bond represented by the general formula 1. (R ¹ is C1-16 alkyl and CH ₂ in the group is O or S
O, S, C≡C, CH = C independently of two or more
R ² may be substituted with H, COO or OCO;
Alkyl terminal methyl of 10 is tree or mono - may be fluorinated; A ¹ is the same group as A ^4, trans -
1,4-cyclohexylene or 1,3-dioxane
2,5-diyl; A ² and A ³ are independently 1,4-phenylene or halogen mono - tetrasubstituted 1,4-phenylene; A ⁴
Is the same group as A ² and A ³ , pyrimidine-2,5-diyl or pyridine-2,5-diyl; Z ¹ is OCF ₂ , CF ₂
O, SCF ₂ or CF ^₂ S; Z ₂ is methyl or mono-, di -
Tri - fluorinated methyl, _{ethyl, CH 2 CF 3, CF 2} C
H ₃ or CF ₂ CF ₃ ; Z ³ is a single bond, O or COO; m
¹ and m ² are not 0 or 1 at the same time, and m ³ is an integer of 0 to 8

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel optically active compound having a difluoromethylene bond, a liquid crystal composition using the same, and a liquid crystal display device using the liquid crystal composition.

[0002]

2. Description of the Related Art Liquid crystals are widely used as materials for display devices. Many liquid crystal display elements are a twisted nematic type (TN type) which is a display type using a nematic liquid crystal, a super twisted nematic type (STN type) having a twist angle of 200 ° or more, and a thin film transistor (STN type) as a switching element for each pixel An active matrix system using a TFT (TFT) or the like. These liquid crystal display devices have a cathode ray tube (C) in view of the electro-optical response speed.
(RT). On the other hand, display devices using antiferroelectric liquid crystals are superior to nematic liquid crystal display devices in terms of high-speed response and wide viewing angle. Recently, it has been actively researched and its development has been attempted.

The antiferroelectric phase shows three stable states of two ferroelectric states and one antiferroelectric state, and the three-state switching is used for display. The feature of this three-state switching is that it exhibits a steep threshold characteristic and a wide optical hysteresis at the transition between the antiferroelectric phase and the ferroelectric phase (ADL Chandani et al., Journal of Applied Physics, Vol. 27, No. 5, L72
9, 1988). By combining this feature with the simple matrix method, a display having both a wide viewing angle and a high contrast is possible.

Further, recently, a thresholdless antiferroelectric liquid crystal having no threshold value (Daikara, J. Mater. Che.
m. , 6 (4), p. 671, 1996) or a ferrielectric liquid crystal (JP-A-8-337555). These liquid crystals show a V-shaped optical response and TFT
In combination with the active matrix method, a display element that can easily display gradations, which is difficult with the simple matrix method, can be realized (Japanese Patent Laid-Open No. 7-64056).

When a tristable antiferroelectric liquid crystal is used for a display device, it is necessary to satisfy requirements such as a wide operating temperature range including around room temperature and a low threshold voltage. In the case of a thresholdless antiferroelectric liquid crystal, there is no clear threshold value, a V-shaped optical response is exhibited, and a liquid crystal material with little hysteresis is required. Further, as in the case of a general liquid crystal compound, stability to light and heat, good compatibility, and the like are required.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent liquid crystal material which is useful as a component of an antiferroelectric liquid crystal composition.

[0007]

Means for Solving the Problems The present inventors searched for an optically active compound having a difluoromethylene group as a bonding group, and found that an optically active compound was suitably used as a component of an antiferroelectric liquid crystal composition. The inventors have found a compound that can be formed, and have completed the present invention.

Some liquid crystal compounds having a difluoromethylene group in the partial structure are known. For example, it is disclosed in JP-A-2-289529 and JP-A-5-112778. However, there is no disclosure of the optically active compound of the present invention, and no disclosure of a compound having a difluoromethylene bond exhibiting antiferroelectricity, which is the subject of the present invention.

The compound having a difluoromethylene bond of the present invention is represented by the following items 1) to 4).

1) General formula (1)

Embedded image (Wherein, R ¹ is a linear or branched C 1-16
And one or two alkyl groups present in the group
More than five -CH ₂ - each independently -O -, - S-,
-C≡C-, -CH = CH-, -COO- or -OC
-O- or -S
R ² is a linear or branched alkyl group having 1 to 10 carbon atoms, and -CH _{3 at the} end of the alkyl chain is replaced by -CF ₃ or -CH ₂ F. A ¹ is 1,4-phenylene, 1,4-phenylene substituted with 1 to 4 halogen atoms, trans-1,4-cyclohexylene, 1,3-dioxane-2,5 - diyl, pyrimidine-2,5-diyl or pyridine-2,5-diyl; a ² and a ³ are substituted with independently 1,4-phenylene or 1 to 4 halogen atoms, 4 - be a phenylene; a ⁴ is 1,4-phenylene, be 1-4 1,4-phenylene, pyrimidine-2,5-diyl or pyridine-2,5-diyl which is substituted with a halogen atom; Z ¹ is -OC
F ₂ —, —CF ₂ O—, —SCF ₂ — or —CF ₂ S—; Z ² is —CH ₃ , —CFH ₂ , —CF ₂ H, —C
_{F 3, -CH 2 CH 3,} -CH 2 CF 3, be -CF ₂ CH ₃ or -CF ₂ CF ^_3; Z ₃ is a single bond, -O- or -
COO—, m ¹ and m ² are each 0 or 1, but not simultaneously 1, and m ³ is an integer of 0 to 8; * indicates an optically active carbon. A compound having a difluoromethylene bond represented by the formula:

2) In the general formula (1), R ¹ is a linear alkyl group having 1 to 16 carbon atoms, and one —CH ₂ — existing in this group is replaced by —O—. R ² is a linear alkyl group having 1 to 10 carbon atoms; A ¹ , A ² and A ⁴ are each independently 1,4-phenylene or 1 to 4 hydrogen atoms each independently having F 4 or it is a 1,4-phenylene substituted by Cl; Z ¹ is -CF ₂ O- or -OCF ₂ - a and; Z ² is an -CH ₃ or -CF _3; Z ³ is a single bond M ¹ = 1, m
² = 0, m ³ is an integer of 0 to 8; * indicates an optically active carbon, the compound having a difluoromethylene bond according to the above item 1).

3) In the general formula (1), R ¹ is a linear alkyl group having 1 to 16 carbon atoms, and one —CH ₂ — existing in this group is replaced by —O—. R ² is a linear alkyl group having 1 to 10 carbon atoms; A ¹ , A ² and A ⁴ are each independently 1,4-phenylene or 1 to 4 hydrogen atoms each independently having F 4 Or Cl-substituted 1,4-phenylene; Z ¹ is —CF ₂ O—; Z ² is —CH ₃ ; Z ³ is a single bond; m ¹ = 1, m ² = m ³ = 0; the compound having a difluoromethylene bond according to the above item 1), wherein * represents an optically active carbon.

4) In the general formula (1), R ¹ is a linear alkyl group having 1 to 16 carbon atoms, and one —CH ₂ — existing in this group is replaced by —O—. R ² is a linear alkyl group having 1 to 10 carbon atoms; A ¹ , A ² and A ⁴ are each 1,4-phenylene or 1 to 4 hydrogen atoms each independently being F or Cl is 1,4-phenylene; Z ¹ is-
CF ₂ O-a and; Z ² is an -CF _3; Z ³ is -O-
M ¹ = 1, m ² = m ³ = 0; * represents a compound having a difluoromethylene bond according to the above item 1), which represents an optically active carbon.

The liquid crystal composition of the present invention is shown in the following item 5). 5) At least one compound having a difluoromethylene bond according to any one of the above 1) to 4)
A liquid crystal composition containing a seed.

The liquid crystal display device of the present invention is described in the following item 6). 6) A liquid crystal display device comprising a liquid crystal composition containing at least one compound having a difluoromethylene bond according to any one of the above 1) to 4).

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Specific examples of each group of the general formula (1) according to the compound of the present invention will be described.

Preferred examples of A ^{1 in the} general formula (1) are shown below.

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Preferred examples of A ² or A ^{3 in} the general formula (1) are shown below.

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Preferred examples of A ^{4 in the} general formula (1) are shown below.

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As preferred specific examples of the compound of the present invention, there are shown 12 types of structures represented by the following formulas (1-1) to (1-12). (The optically active group R ^* in the formula is

Embedded image Expressed by )

(1-1) R ¹ -A ¹ -A ² -CF ₂ O-A ⁴ -COO-R ^* (1-2) R ¹ -A ² -CF ₂ O-A ³ -A ⁴ -COO -R ^* (1-3) R ¹ -A ² -CF ₂ O-A ⁴ -COO-R ^* (1-4) R ¹ -A ¹ -A ² -OCF ₂ -A ⁴ -COO-R ^* ( 1-5) R ¹ -A ² -OCF ₂ -A ³ -A ⁴ -COO-R ^* (1-6) R ¹ -A ² -OCF ₂ -A ⁴ -COO-R ^* (1-7) R ¹ -A ¹ -A ² -CF ₂ SA ⁴ -COO-R ^* (1-8) R ¹ -A ² -CF ₂ SA ³ -A ⁴ -COO-R ^* (1-9) R _{^{1 -A 2 -CF 2 S-A}} 4 -COO-R * (1-10) R 1 -A 1 -A 2 -SCF 2 -A 4 -COO-R * (1-11) R 1 -A 2 _{^{-SCF 2 -A 3 -A 4 -COO-}} R * (1-12) R 1 -A 2 -SCF 2 -A 4 -CO OR ^*

Further, when A ¹ , A ² , A ³ and A ⁴ are limited to preferred groups, the compounds represented by the following formulas can be shown as specific examples of the compounds of the present invention.

[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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[0030]

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In these formulas, R ¹ is preferably an alkyl group having 1 to 16 carbon atoms, an alkoxy group or an alkanoyloxy group. As the alkyl group, a straight-chained one having 2 to 12 carbon atoms, specifically, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and the like are preferable. As the alkoxy group, a straight-chain 2 to 12 carbon atoms, specifically, ethoxy, propyloxy, butyloxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy,
Dodecyloxy and the like are preferred. Examples of the alkanoyloxy group include straight-chain carbon atoms having 2 to 12, specifically ethanoyloxy, propanoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonanoyloxy, decanoyl Oxy, undecanoyloxy, dodecanoyloxy and the like are preferred.

The optically active group and the core structure of the compound of the present invention are linked by an ester group. Therefore, an optically active alcohol is used as a raw material for producing the optically active portion. The optically active alcohol used for producing the compound of the present invention can be represented by the general formula (2).

[0033]

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The alcohol represented by the general formula (2) is represented by R
^TwoIs a linear or branched alkyl having 1 to 10 carbon atoms
Group of the alkyl chain terminal -CH_ThreeIs -CF_ThreeOr-
CH _TwoMay be replaced by F, Z^TwoIs -CH_Three, -C
FH_Two, -CF_TwoH, -CF_Three, -CH_TwoCH_Three, -CH_TwoC
F_Three, -CF_TwoCH_ThreeOr -CF_TwoCF_ThreeAnd Z^ThreeIs simply
A bond, —O— or —COO—, m^ThreeIs from 0 to 8
And * represents an optically active carbon.

In the general formula (2), Z ² represents —CH ₃ ,
_{CFH 2, -CF 2 H, -CF} 3, -CH 2 CH 3, -CH 2
CF ₃ , —CF ₂ CH ₃ or —CF ₂ CF ₃ , Z ³ is a single bond, R ² is a linear alkyl group having 1 to 10 carbon atoms, and m ³ is 0 to 8 Many of the integers are known alcohols and are readily available. For example, 1- (trifluoromethyl) -alkanols can be prepared by the method of Suzuki et al. (Liquid Crystals, Vo)
16, No. 2, p. 167, 1989). The specific structure is shown below.

[0036]

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[0037]

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In the general formula (2), Z ² represents —CH ₃ ,
_{CH 2 F, -CF 2 H,} -CF 3, -CH 2 CF 3 or -
Alcohols represented by CF ₂ CF ₃ , Z ³ is a single bond, R ² is a branched alkyl group having 1 to 8 carbon atoms and m ³ is 0 to 8 are disclosed in -195
004. The specific structure of the alcohol is shown below. Such an alcohol is important because it can produce the compound of the general formula (1) which can provide a large tilt angle.

[0039]

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In the general formula (2), Z ² is —CH ₃ or —CF ₃ , Z ³ is —O— or —COO—, and R ² is a linear C 1-8. An optically active alcohol having an alkyl group (-CH _{3 at the} terminal of the alkyl chain may be replaced by -CF ₃ or -CH ₂ F) and m ³ represented by an integer of 0 to 8 is disclosed in 64-315
4, JP-A-5-983, JP-A-10-139706, JP-A-10-87541, and the like, and the present inventors further describe a method for producing a compound having the structure described in JP-A-10-1983.
-248593. Therefore, these optically active alcohols are available as starting materials for the compounds of the present invention. The specific structure is shown below. The compound of the general formula (1) which can be produced from such an alcohol can be used for lowering the threshold voltage.

[0041]

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The production examples of the compounds of the present invention are shown below. The formulas (1-1), (1-2), (1-3), and (1-
The compounds represented by 7), (1-8) and (1-9) can be produced by the following route. The corresponding ester derivative (c) is obtained by an esterification reaction between the carboxylic acid derivative (a) and a phenol or thiophenol derivative (b) having a cyano group. The ester derivative (c) was converted to [2,4
-Bis (4-methoxyphenyl) -1,3-dithia-2,
4-phosphoethane-2,4-disulfide] (hereinafter referred to as Lawesson's reagent) to give a thioester derivative (d). In this reaction, a solvent such as benzene, toluene, mesitylene, and chlorobenzene can be used. The thioester derivative (d) is converted to N-bromosuccinimide (hereinafter referred to as NBS), N
Difluoro by fluorination with a hydrogen fluoride pyridine complex or the like in the presence of iodosuccinimide (hereinafter referred to as NIS) or 1,3-dibromo-5,5-dimethylhydantoin (hereinafter referred to as DBH); A methyleneoxy derivative or a difluoromethylenethioether derivative (e) is obtained. The carboxylic acid derivative (f) is obtained by hydrolyzing (e). The compound (1-1), (1-2), (1-3) of the present invention is obtained by an esterification reaction between (f) and the optically active alcohol (2).
(1-7), (1-8) and (1-9) can be produced.

[0043]

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The formulas (1-4) and (1-
Compounds represented by 5), (1-6), (1-10), (1-11) and (1-12) can be produced by the following route. Phenol or thiophenol derivative (g) and p
-The corresponding ester derivative (i) is obtained by the esterification reaction with the cyano-substituted carboxylic acid derivative (h).
The thioester derivative (j) is obtained by reacting (i) with a Lawson reagent or the like. By fluorinating the thioester derivative (j) with a hydrogen fluoride pyridine complex or the like in the presence of NBS, NIS or DBH, an oxydifluoromethylene derivative or a thiodifluoromethylene derivative (k) is obtained. The carboxylic acid derivative (l) is obtained by hydrolyzing (k). The compounds (1-4), (1-5), (1-6), (1) of the present invention are subjected to an esterification reaction between (1) and the optically active alcohol (2).
-10), (1-11) and (1-12) can be produced.

[0045]

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In the general formula (1), A ² is 1,4-phenylene, A ⁴ is 1,4-phenylene or 1 to 4 hydrogen atoms are each independently substituted with a halogen atom such as F or Cl. 1,4-phenylene, Z ¹ is —CF ₂ O—,
The compound of the formula (1-13) represented by m ¹ = 1 and m ² = 0 can be produced as follows. A Grignard reagent is prepared by reacting 1/2 equivalent of metal magnesium with 1,4-dibromobenzene, and carbon disulfide is added thereto to obtain 4-bromodithiobenzoic acid (m). (M) and a 4-cyanophenol derivative (PCNO
The thioester derivative (n) is obtained by an esterification reaction with H). The difluoromethyleneoxy derivative (o) is obtained by fluorinating (n) with a fluorinating agent such as a hydrogen fluoride pyridine complex. A cross-coupling reaction between (o) and the boronic acid derivative (PB) gives (p). The carboxylic acid derivative (r) is obtained by directly hydrolyzing (p). Alternatively, (r) can also be obtained by reducing (p) to give an aldehyde derivative (q) once and then oxidizing it. (1-13) can be produced by an esterification reaction between (r) and the optically active alcohol (2).

[0047]

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[0048]

The compounds of the present invention will be described in more detail with reference to the following Examples and Comparative Examples. In the following Examples and Comparative Examples, various physical property values were measured by the following methods. Phase transition temperature: The sample was placed on a slide glass, the one covered with a cover glass was placed on a hot stage, and the temperature was measured at a rate of 1 ° C./min under a deflection microscope. In the phase transition, N is a nematic phase, SA is a smectic A phase, SC is a smectic C phase, and SC ^* is a chiral smectic C.
SCA ^* indicates an antiferroelectric phase, SCγ ^* indicates a ferrielectric phase, SX indicates an unidentified smectic phase, and Iso indicates an isotropic liquid. Melting point: 1 ° C./m using differential scanning calorimetry (DSC)
The temperature was measured by raising the temperature in. Optical response: Each composition was injected into an alignment-treated cell having an electrode spacing of 2 μm or 5 μm, Vpp of 20 V,
It was measured from a change in transmitted light intensity when a rectangular wave of 1 kHz was applied. Threshold voltage: one of a pair of substrates obtained by applying a polyimide-based alignment film to a glass substrate provided with a transparent electrode is rubbed to face each other, and is injected in a liquid phase into a cell having an electrode spacing of 5 μm. Slowly cooled to SCA * phase. The threshold voltage of the transition between the antiferroelectric phase and the ferroelectric phase is determined by observing the optical response and applied voltage when a 50 mHz triangular wave is applied to the liquid crystal cell with a two-phenomenon oscilloscope. It was measured from the change in the optical response under a suitably determined applied voltage.

Example 1 4- (difluoro-4'-octyloxybiphenyl-
Production of 4-yl-methyloxy) benzoic acid = 1-methylheptyl ester (compound [6]) (First step) 235 g of 1,4-dibromobenzene and 235 g of tetrahydrofuran (hereinafter referred to as T
A Grignard reagent was prepared by dropwise addition of a 1.5 L solution (abbreviated as HF). 100 g of carbon disulfide was dripped there and stirred for 1 hour. 500 ml of 6N hydrochloric acid was added, extracted with 1 L of ether, and dried over anhydrous magnesium sulfate. The solvent was distilled off to obtain 150 g of 4-bromodithiocarboxylic acid. This was used for the second step without purification.

(Second stage) 16.8 g of sodium hydride
And 100 ml of THF, 50 g of 4-bromodithiobenzoic acid synthesized in the first step and THF1
00 ml solution, followed by p-cyanophenol 2
A solution consisting of 5 g and 100 ml of THF was added dropwise.
After stirring at room temperature for 1 hour, a solution composed of 52.9 g of iodine and 200 ml of THF was added dropwise, and the mixture was stirred at room temperature for 12 hours. Pour 300 ml of water and add chloroform 70
Extracted with 0 ml. Chloroform layer 50m with 6N hydrochloric acid
l, washed with saturated aqueous sodium carbonate and dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent is subjected to silica gel column chromatography (eluted with chloroform).
After refining with, recrystallization with ethanol was performed to obtain 21 g of 4-bromothiobenzoic acid = 4-cyanophenyl ester. Its melting point was 155-158 ° C.

(Third Step) A solution comprising 38 g of DBH and 200 ml of dichloromethane was cooled to -60 ° C.
25 g of hydrogen fluoride pyridine complex (70%) was added dropwise thereto. Next, 21 g of 4-bromothiobenzoic acid = 4-cyanophenyl ester and 150 ml of dichloromethane
Was added dropwise over 30 minutes, and the mixture was stirred for 2 hours while maintaining -60 ° C. The reaction solution was poured into 500 ml of saturated aqueous sodium carbonate containing ice to terminate the reaction. The dichloromethane layer obtained by liquid separation was washed with water, dried over anhydrous magnesium sulfate, the solvent was distilled off, and the resulting residue was purified by silica gel column chromatography (eluted with chloroform), and re-used with heptane. Crystallize α,
20 g of α-difluoro-4-bromobenzyl 4-cyanophenyl ether was obtained. Its melting point was 71-72 ° C.

(Fourth step) α, α-difluoro-4-bromobenzyl 4-cyanophenyl ether 6 g, octyloxybenzeneboronic acid 5 g, sodium carbonate
A solution consisting of 1 g, 0.4 g of tetrakis palladium (0), 150 ml of dimethoxyethane and 25 ml of water was added to 9
Refluxed for hours. 50 ml of water was added, and chloroform 200 was added.
Then, the resulting mixture was extracted with an organic solvent, and the chloroform layer was dried over anhydrous magnesium sulfate. Then, the residue obtained by distilling off the solvent was purified by silica gel column chromatography (eluted with chloroform), recrystallized with ethanol, and 8.6 g of difluoro- (4-octyloxybiphenyl) methyl cyanophenyl ether was obtained. I got This shows a liquid crystal phase, and its phase transition temperature (° C.) is Cr 113 N 146.
It was Iso.

(Fifth step) A solution consisting of 2.6 g of difluoro- (4-octyloxybiphenyl) methyl cyanophenyl ether and 30 ml of THF was heated at -60 ° C.
145 ml of a 1M solution of diisobutylaluminum hydride was added dropwise thereto. After stirring at -60 ° C for 15 minutes, the mixture was slowly returned to room temperature and stirred for 5 hours. 50 ml of 6N hydrochloric acid was added, extracted with ethyl acetate, and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by distilling off the solvent was purified by silica gel column chromatography to obtain 1.2 g of difluoro- (4-octyloxybiphenyl) methylformylphenyl ether. Melting point was 63 ° C.

(Sixth step) While maintaining 0 ° C, 0.8 ml of 8N Jones reagent was added dropwise to a solution consisting of 0.4 g of difluoro- (4-octyloxybiphenyl) methyl formylphenyl ether and 60 ml of acetone.
I stirred for another 3 hours. The reaction solution was filtered to remove insolubles, and the filtrate was poured into 400 ml of water. The precipitated crystals were separated and dried, and 0.38 g of difluoro-
(4-Octyloxybiphenyl) methyl hydroxycarbonylphenyl ether was obtained. This melting point is 19
3 to 195 ° C.

(Seventh Step) A solution consisting of 0.12 g of (R) -2-octanol (optical purity 100% ee), 0.04 g of sodium hydride and 1 ml of dioxane was added to 3
After refluxing for 5 hours, 5 ml of dioxane was added for dilution to prepare an alcoholate solution. Using another reactor, 0.13 g of carbonylbisimidazole was added to a solution consisting of 0.38 g of difluoro- (4-octyloxybiphenyl) methylhydroxycarbonylphenyl ether and 15 ml of dimethylformamide, and the mixture was stirred at room temperature for 1 hour. The alcoholate solution prepared above was added thereto, and 1
Stirred at 00 ° C for 5 hours. Water was added and the mixture was extracted with toluene, and the toluene layer was dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent was purified by silica gel column chromatography, and recrystallized twice from ethanol to obtain 0.1 g of 4- (4-octyloxybiphenyl-4-l.
Difluoromethyleneoxy) -benzoic acid-1-methylheptyl ester (compound [6]) was obtained.

Example 2 4- (difluoro-4'-nonyloxybiphenyl-4
Preparation of (-yl-methyloxy) benzoic acid = 1-methylheptyl ester (compound [7]) (First step) 2.5 g of 4-nonyloxybiphenylcarboxylic acid chloride, 0.8 g of p-cyanophenol, 5 ml of pyridine And 15 ml of toluene were refluxed for 3 hours. 50 ml of toluene and 10 m of water are added to the obtained solution.
1 was added and the mixture was separated. Wash the toluene layer with 6N hydrochloric acid and water,
It was dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by distilling off the solvent was purified by silica gel column chromatography (eluted with chloroform), and further recrystallized with ethanol to obtain 2 g of 4-cyanophenyl = 4'-nonyloxybiphenylcarboxylate. Was. Its melting point was 118 ° C.

(Second step) 4-cyanophenyl = 4'-
A solution consisting of 1 g of nonyloxybiphenylcarboxylate, 0.92 g of Lawesson's reagent and 20 ml of mesitylene was refluxed for 10 hours. Toluene and water were added to the residue obtained by distilling mesitylene under reduced pressure and extracted. The toluene layer was sequentially washed with 6N hydrochloric acid, saturated aqueous sodium carbonate and water, and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by distilling off the solvent was purified by silica gel column chromatography (toluene) to obtain 0.3 g of 4-cyanophenyl = 4'-nonyloxybiphenylthiocarboxylate. The 4-cyanophenyl = 4'-nonyloxybiphenylthiocarboxylate obtained in this way is fluorinated by the method of Example 1 (third step), and further fluorinated from Example 1 (fifth step) to (7th step). 4- (difluoro-4'-nonyloxybiphenyl-4-yl-methyloxy) benzoic acid =
1-methylheptyl ester (compound [7]) can be produced.

Example 3 2-fluoro-4- (difluoro-4'-octyloxybiphenyl-4-yl-methyloxy) benzoic acid = 1
-Preparation of methylheptyl ester (compound [11]) (1st step) 14.4 g of sodium hydride and THF
4-bromodithiobenzoic acid 4 in a 100 ml solution
Solution consisting of 3 g and 100 ml of THF, then 4-
24.6 g of cyano-3-fluorophenol and TH
A solution consisting of 100 ml of F was added dropwise. After stirring at room temperature for 1 hour, 45.3 g of iodine and 200 m of THF were added.
The resulting solution was added dropwise and stirred at room temperature for 12 hours. 300 ml of water was poured and extracted with 700 ml of chloroform. The chloroform layer was washed with 50 ml of 6N hydrochloric acid and saturated aqueous sodium carbonate and dried over anhydrous magnesium sulfate. Then, the residue obtained by distilling off the solvent was purified by silica gel column chromatography (eluted with chloroform), and recrystallized with ethanol to obtain 21 g of 4-
Bromothiobenzoic acid = 4-cyano-3-fluorophenyl ester was obtained.

(Third Step) A solution comprising 29 g of DBH and 100 ml of dichloromethane was cooled to -60 ° C.
15 g of hydrogen fluoride pyridine complex (70%) was added dropwise thereto. Next, 4-bromothiobenzoic acid = 4-cyano-3-
A solution consisting of 17 g of fluorophenyl ester and 200 ml of dichloromethane was added dropwise over 30 minutes, and the mixture was stirred for 2 hours while maintaining the liquid temperature at -60 ° C. The reaction solution was poured into 500 ml of saturated aqueous sodium carbonate containing ice to terminate the reaction. The dichloromethane layer obtained by liquid separation was washed with water and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by distilling off the solvent is purified by silica gel column chromatography (eluted with chloroform), and recrystallized using heptane to obtain α, α-difluoro-4-bromobenzyl 4-cyano-. 8.7 g of 3-fluorophenyl ether were obtained. Its melting point was 116-118 ° C.

(Fourth Step) 1.4 g of α, α-difluoro-4-bromobenzyl 4-cyano-3-fluorophenyl ether, octyloxybenzeneboronic acid 1.1
A solution consisting of 2 g, 0.63 g of sodium carbonate, 0.1 g of tetrakis palladium (0), 30 ml of dimethoxyethane and 5 ml of water was refluxed for 9 hours. 10 ml of water was added, extracted with 60 ml of chloroform, and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by distilling off the solvent was purified by silica gel column chromatography (eluted with chloroform), and recrystallized with ethanol to obtain 0.9 g of difluoro- (4'-octyloxybiphenyl-4-ethyl).
Yl) Methyl 4-cyano-3-fluorophenyl ether was obtained. This showed a liquid crystal phase, and its phase transition temperature (° C.) was Cr 58N 121 Iso.

(Fifth Step) Difluoro- (4'-octyloxybiphenyl-4-yl) methyl 4-cyano-
0.9 g of 3-fluorophenyl ether and THF2
The solution consisting of 0 ml was cooled to -60 ° C, and 4 ml of a 1 M solution of diisobutylaluminum hydride was added dropwise thereto. After stirring at -60 ° C for 15 minutes, the mixture was slowly returned to room temperature and stirred for 5 hours. 10 ml of 6N hydrochloric acid was added, extracted with ethyl acetate, and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by evaporating the solvent was purified by silica gel column chromatography, and 0.4 g of difluoro- (4'-octyloxybiphenyl-4-yl) methyl 4-formyl-3-fluorophenyl ether was obtained. I got Melting point was 62-63 ° C.

(Sixth step) 8N Jones was added to a solution comprising 0.4 g of difluoro- (4'-octyloxybiphenyl-4-yl) methyl 4-formyl-3-fluorophenyl ether and 20 ml of acetone while maintaining 0 ° C. 0.7 ml of the reagent was added dropwise, and the mixture was further stirred for 3 hours. The reaction solution was filtered to remove insolubles, and the filtrate was filtered for 10 minutes.
Poured into 0 ml of water. The precipitated crystals were separated and dried to obtain 0.4 g of difluoro- (4'-octyloxybiphenyl-4-yl) methyl 4-hydroxycarbonyl-3-fluorophenyl ether.

(Seventh Step) A solution consisting of 0.13 g of (R) -2-octanol (100% ee optical purity), 0.04 g of sodium hydride and 1 ml of dioxane was added to 3
After refluxing for 5 hours, 5 ml of dioxane was added for dilution to prepare an alcoholate solution. Using a separate reactor, difluoro- (4'-octyloxybiphenyl-4-yl)
0.4 g of methyl 4-hydroxycarbonyl-3-fluorophenyl ether and dimethylformamide 15
carbonylbisimidazole 0.1
4 g was added and stirred at room temperature for 1 hour. The alcoholate solution prepared above was added thereto, and the mixture was stirred at 100 ° C. for 5 hours. Water was added and the mixture was extracted with toluene, and the toluene layer was dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by distilling off the solvent was purified by silica gel column chromatography, and recrystallized twice with ethanol to obtain 0.1 g of 2-fluoro-4- (difluoro-4'-octyloxybiphenyl-phenyl). 4-yl-methyloxy) benzoic acid = 1-methylheptyl ester (compound [11]) was obtained.

Example 4 4- (Difluoro-4'-octyloxybiphenyl-
Production of 4-yl-methyloxy) benzoic acid = 1-trifluoromethylheptyl ester (compound [46]) 0.27 g of (R) -1-trifluoromethylheptanol (optical purity 100% ee), sodium hydride 0.0
After refluxing a solution consisting of 6 g and 1 ml of dioxane for 3 hours, 5 ml of dioxane was added for dilution to prepare an alcoholate solution. Using a separate reactor, difluoro-
To a solution consisting of 0.6 g of (4-octyloxybiphenyl) methylhydroxycarbonylphenyl ether and 15 ml of dimethylformamide was added 0.21 g of carbonylbisimidazole, and the mixture was stirred at room temperature for 1 hour.
The alcoholate solution previously prepared was added thereto, and 100
Stirred at ° C for 5 hours. Add water and extract with toluene,
The toluene layer was dried with anhydrous magnesium sulfate. The residue obtained by distilling off the solvent was purified by silica gel column chromatography, and recrystallized twice from ethanol to obtain a residue.
g of 4- (4-octyloxybiphenyl-4-difluoromethyleneoxy) -benzoic acid-1-trifluoromethylheptyl ester (compound [46]) was obtained.

According to Examples 1 to 4, the following formula [1]-
The compound of the present invention represented by [220] can be produced. The structure and phase transition temperature (° C.) are shown.

[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078]

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[0079]

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[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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Example 4 Optical Response of Compound [46] at 60 ° C. FIGS. 1 and 2
Shown in The optical response of compound [46] at a cell thickness of 5 μm (FIG. 1) showed tristable switching, and a cell thickness of 2 μm (FIG. 2) showed a V-shaped optical response with no threshold.

Example 5 (Composition Example 1) A liquid crystal composition (MIX1) having the following composition was prepared.

Embedded image The phase transition temperature of the composition (MIX1) is Cr unknown.
SCA ^* 65.5 SC ^* 73.8 SA 80.
2 Iso. FIG. 3 shows the optical response to a triangular wave voltage at 60 ° C. It showed a V-shaped optical response without hysteresis.

[0090]

The compound of the present invention is characterized in that the compound represented by the formula (1)
¹ includes —CF ₂ —, and many of the compounds exhibit an antiferroelectric phase. Further, it is stable against heat, light, and the like, and has excellent compatibility with other liquid crystal components. The compounds of the present invention show a V-shaped optical response without threshold voltage by optimizing the cell conditions. Therefore, by using the compound of the present invention or a composition containing the compound of the present invention, a liquid crystal display element in which gradation display is easy can be realized.

[Brief description of the drawings]

FIG. 1 is a view showing the optical response of compound [46] to a triangular wave voltage at 60 ° C. (cell thickness: 5 μm).

FIG. 2 is a view showing the optical response of compound [46] to a triangular wave voltage at 60 ° C. (cell thickness: 2 μm).

FIG. 3 is a view showing the optical response of a composition (MIX1) to a triangular wave voltage at 75 ° C. (cell thickness: 2 μm).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C07D 213/65 C07D 213/65 213/80 213/80 239/26 239/26 239/34 239/34 239 / 54 319/06 319/06 C09K 19/20 C09K 19/20 19/28 19/28 19/30 19/30 19/34 19/34 G02F 1/13 500 G02F 1/13 500 C07M 7:00 // C07M 7:00 C07D 239/55 (72) Inventor Hideo Saito 1 Chisso stone at 5 Goi Kaigan, Ichihara-shi, Chiba Pref. BB08 CA02 CA06 CA08 CA16 CA42 CB02 CB04 CB08 DA01 4H006 AA01 AA03 AB64 BJ50 BM10 BM30 BM71 BP30 TA04 TB39 TB57 TB61 4H027 BA07 BD01 BD05 BD08 BD21 BD24 CB08 CE08 CF08 CH08 CN08 CU08 DA08 DB08 DC08 DD08 DE08

Claims (6)

[Claims] 1. A compound of the general formula (1) (Wherein, R ¹ is a linear or branched C 1-16
And one or two alkyl groups present in the group
More than five -CH ₂ - each independently -O -, - S-,
-C≡C-, -CH = CH-, -COO- or -OC
-O- or -S
R ² is a linear or branched alkyl group having 1 to 10 carbon atoms, and -CH _{3 at the} end of the alkyl chain is replaced by -CF ₃ or -CH ₂ F. A ¹ is 1,4-phenylene, 1,4-phenylene substituted with 1 to 4 halogen atoms, trans-1,4-cyclohexylene, 1,3-dioxane-2,5 - diyl, pyrimidine-2,5-diyl or pyridine-2,5-diyl; a ² and a ³ are substituted with independently 1,4-phenylene or 1 to 4 halogen atoms, 4 - phenylene; A ⁴ is 1,4
-Phenylene, 1,4-phenylene substituted with 1 to 4 halogen atoms, pyrimidine-2,5-diyl or pyridine-2,5-diyl; Z ¹ is —OCF
_{2 -, - CF 2 O -} , - SCF 2 - , or -CF ₂ S- and and; Z ² is _{-CH 3, -CFH 2, -CF 2} H, -CF 3,
_{-CH 2 CH 3, -CH 2 CF} 3, -CF 2 CH 3 or -C
It is F ₂ CF ^_3; Z ₃ is a single bond, -O- or -COO
And m ¹ and m ² are each 0 or 1 but not simultaneously 1, and m ³ is 0 to 8; * indicates an optically active carbon. A compound having a difluoromethylene bond represented by the formula: 2. In the general formula (1), R ¹ is a linear alkyl group having 1 to 16 carbon atoms, wherein one —CH ₂ — existing in this group is replaced by —O—. R ² is a linear alkyl group having 1 to 10 carbon atoms; A ¹ , A ² and A ⁴ are each independently 1,4-phenylene or 1 to 4 hydrogen atoms each independently having F 4 Or 1,4-phenylene substituted with Cl; Z ¹ is-
CF ₂ O— or —OCF ₂ —; Z ² is —CH ₃ or —CF ₃ ; Z ³ is a single bond; m ¹ = 1, m ²
The compound having a difluoromethylene bond according to claim 1, wherein = 0 and m ³ are integers of 0 to 8; * represents an optically active carbon. 3. In the general formula (1), R ¹ is a linear alkyl group having 1 to 16 carbon atoms, wherein one —CH ₂ — existing in the group is replaced by —O—. R ² is a linear alkyl group having 1 to 10 carbon atoms; A ¹ , A ² and A ⁴ are each independently 1,4-phenylene or 1 to 4 hydrogen atoms each independently having F 4 Or 1,4-phenylene substituted with Cl; Z ¹ is-
CF ₂ O-a and; Z ² is an -CH _3; Z ³ is a single bond; m be ^{1 = 1, m 2 = m} 3 = 0; * the claims consists in showing the optically active carbon Item 6. The compound having a difluoromethylene bond according to Item 1. 4. In the general formula (1), R ¹ is a linear alkyl group having 1 to 16 carbon atoms, wherein one —CH ₂ — existing in the group is replaced by —O—. R ² is a linear alkyl group having 1 to 10 carbon atoms; A ¹ , A ² and A ⁴ are each 1,4-phenylene or 1 to 4 hydrogen atoms each independently being F or C
l is 1,4-phenylene; Z ¹ is -C
F ₂ O-a and; Z ² is an -CF _3; Z ³ is -O-; be ^{m 1 = 1, m 2 =} m 3 = 0; * consists in showing the optically active carbon The compound having a difluoromethylene bond according to claim 1. 5. A liquid crystal composition comprising at least one compound having a difluoromethylene bond according to claim 1. Description: 6. A liquid crystal display device comprising a liquid crystal composition containing at least one compound having a difluoromethylene bond according to claim 1. Description: