JP2002332262A - Fluorene derivative, antiferroelectric liquid crystal composition containing the same, and liquid crystal display device using the same - Google Patents

Abstract

(57) [Summary] (Modified) [PROBLEMS] A novel liquid crystal compound having a fluorene ring,
Provided are a liquid crystal composition containing the same and a liquid crystal display device using the liquid crystal composition. SOLUTION: The compound of the general formula 1. (R ¹ is C 2-20 alkyl, wherein one —CH ₂ — or two non-adjacent —CH ₂ — are independently —
O -, - COO -, - C≡C- or -CH = CH- may be substituted with, R ² is alkyl of C1-10, methyl herein is substituted with trifluoromethyl or fluoromethyl X may be -C≡C- or-
CH ₂ CH ₂ —, A ¹ is 1,4-phenylene or the like, and A ² is methyl, ethyl, methyl in which one or more hydrogen is replaced with fluorine, or one or more hydrogen is replaced with fluorine Wherein A ³ is a single bond, -O- or-
COO-, m is an integer of 0 to 10, and C * represents an asymmetric carbon. )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal compound having a fluorene ring, a liquid crystal composition containing the same and a liquid crystal composition containing the same, which can be suitably used for a liquid crystal display device, particularly an antiferroelectric liquid crystal display device. The present invention relates to a liquid crystal display device using

[0002]

2. Description of the Related Art As a display device using a nematic liquid crystal composition, a twisted nematic (TN) system or the like is known, but an electro-optical response time is longer than that of a display using a cathode ray tube (CRT). On the other hand, a display element using an antiferroelectric liquid crystal composition has a shorter response time and a wider viewing angle than a display element using a nematic liquid crystal composition. Therefore,
This display element is expected to achieve a response time comparable to a CRT.

The antiferroelectric phase of the antiferroelectric liquid crystal composition has a total of 3 in two ferroelectric states and one antiferroelectric state.
Since three stable states are indicated, three-state switching is used for display. The features of the three-state switching are a sharp threshold characteristic and a wide optical hysteresis at the transition between the antiferroelectric phase and the ferroelectric phase (ADL Cha).
ndani et al., Jpn. J. Appl. Phys. , 2
7, No. 5, L729, 1988). A display with a wide viewing angle and high contrast is possible by combining this feature with the simple matrix method.

Recently, an antiferroelectric liquid crystal composition having no threshold (Inui et al., J. Mater. Che.
m. , 6 (4), p. 671, 1996). A display element using this composition exhibits a V-shaped optical response, and by combination with an active matrix method such as a TFT, gradation display which is difficult with a simple matrix method is easy.

[0005]

When an antiferroelectric liquid crystal composition having three stable states is used in a display device, the operating temperature range is wide including around room temperature, and the threshold voltage is low. , And the temperature dependency of the threshold voltage is small. When a thresholdless antiferroelectric liquid crystal composition is used for a display device, there is no clear threshold value, and a V-shaped optical response is exhibited.
It is necessary that the hysteresis is small. Therefore,
The antiferroelectric liquid crystal compound needs to exhibit the above characteristics when the composition is prepared. Further, it is preferable that this compound is stable against light, heat, and the like, has an antiferroelectric phase near room temperature, and has good compatibility with other liquid crystal compounds.

[0006]

Accordingly, the present inventors have made intensive studies to find an antiferroelectric liquid crystal compound satisfying these characteristics and completed the following invention. The present inventors have found that a fluorene derivative having a fluorene ring and having a core structure and an optically active group linked by an ester bond is suitable as a component of the antiferroelectric liquid crystal composition. The present invention relates to a compound having a fluorene ring represented by the formula (1), a composition containing the compound, and a liquid crystal display device using the composition.

[0007] In the formula, R ¹ is alkyl of 2 to 20 carbon atoms, one -CH ₂ in the alkyl - or not adjacent two -CH ₂ - each independently -O -, - COO -, - C
R ² is alkyl having 1 to 10 carbons, wherein methyl in the alkyl may be replaced by trifluoromethyl or fluoromethyl; Is —C≡C— or —CH ₂ CH ₂ —, and A ¹ is 1,4-phenylene, or at least one hydrogen independently represents fluorine, chlorine, bromine,
And 1,4-phenylene substituted with at least one of trifluoromethyl and A ² is methyl, ethyl, methyl in which at least one hydrogen is replaced with fluorine, or at least one hydrogen is replaced with fluorine Ethyl, and A ³ is a single bond, -O-, or-
COO-, m is an integer of 0 to 10, and C * represents an asymmetric carbon. The compound represented by the formula (1) may be referred to as a compound (1) in some cases.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the compound (1), X is -C≡C-
Or -CH ₂ CH ₂ - because it is, it can be represented by compounds (1-1) and (1-2).

A ¹ of compound (1) is 1,4-phenylene or 1,4-phenylene in which at least one hydrogen is independently replaced by at least one of fluorine, chlorine, bromine and trifluoromethyl. is there. Preferred are the following phenylenes. These eight phenylenes and compounds (1-1) and (1-
Compounds (1-1-1) to (1-1) obtained by combining
-8) and compounds (1-2-1) to (1-2-8) are preferred.

[0010]

[0011]

R ¹ of the compound (1) has 2 to 20 carbon atoms.
And preferably alkyl having 5 to 16 carbon atoms. Straight chain alkyls are preferred over branched alkyls. In these alkyl, one -CH ₂ -
Or two non-adjacent -CH ₂ -are each independently-
O-, -COO-, -C≡C-, or -CH = CH-
May be replaced by For example, alkoxy, alkoxyalkyl, alkoxyalkoxy, alkanoyloxy, alkoxycarbonyl, alkynyl, alkynyloxy, alkenyl, alkenyloxy and the like.

Preferred alkyls are ethyl, propyl,
Butyl, pentyl, isopentyl, hexyl, isohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl. Preferred alkoxy is ethyloxy, propyloxy, butyloxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy,
Decyloxy, undecyloxy, dodecyloxy, tridecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy, heptadecyloxy and octadecyloxy.

Preferred alkanoyloxy are ethanoyloxy, propanoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonanoyloxy, decanoyloxy, undecanoyloxy, dodecanoyloxy , Tridecanoyloxy, tetradecanoyloxy, pentadecanoyloxy, hexadecanoyloxy, heptadecanoyloxy and octadecanoyloxy.

R ² of the compound (1) has 1 to 10 carbon atoms.
And preferably linear alkyl. The methyl in the alkyl may be replaced by trifluoromethyl or fluoromethyl. Such R
² is, for example, trifluoromethyl, 2,2,2-trifluoroethyl, fluoromethyl, 2-fluoroethyl. A ^{2 in} compound (1) is methyl, ethyl, fluorine-substituted methyl, or fluorine-substituted ethyl. Preferably, methyl, fluoromethyl, difluoromethyl, trifluoromethyl, 1,1-difluoroethyl, 2,2,
2-trifluoroethyl and 1,1,2,2,2-pentafluoroethyl. More preferred are methyl and trifluoromethyl. A ³ of compound (1) is
It is a single bond, -O- or -COO-. Preferably, it is a single bond.

Another form of the preferred compound (1) is as follows:
It is a cage. In the formula (1), R ¹Is from 2 to 2 carbon atoms
0 alkyl and one -CH in this alkyl_Two
-Is -O-, -COO-, -C≡C-, or -CH =
CH— may be replaced by R^TwoIs 1 to 1 carbon atoms
0 linear alkyl;^TwoIs methyl and A^ThreeIs simply
A compound that is a bond. In the formula (1), R¹Is charcoal
Straight-chain alkyl having a prime number of 2 to 20, wherein
One -CH_Two-Is -O-, -COO-, -C≡C
-, Or -CH = CH-;
^TwoIs a linear alkyl having 1 to 10 carbons,^TwoIs bird
A compound that is fluoromethyl.

To produce the compound (1), an optically active secondary alcohol (2) is used as a raw material. In the alcohol (2), R ² is alkyl having 1 to 10 carbons, wherein methyl in the alkyl may be replaced by trifluoromethyl or fluoromethyl, and A ² is methyl, ethyl and at least one hydrogen Methyl substituted by fluorine, or ethyl wherein at least one hydrogen is replaced by fluorine, A ³ is a single bond, —O—, or —COO—, and m is 0 to 1
It is an integer of 0, and C * represents an asymmetric carbon.

Of the alcohols (2), most of the compounds in which A ³ is a single bond are known and can be easily obtained. For example, 1- (trifluoromethyl) alkanols can be obtained by the method of Suzuki et al. (Liquid C
rystals, Vol 6, No. 2, p. 167, 198
9 years). The following compounds can be prepared by this method or by combining with known synthetic methods.

[0019]

[0020]

Among the alcohols (2), compounds wherein A ³ is --O-- or --COO-- are disclosed in JP-A-64-3154.
JP, JP-A-5-983, JP-A-10-139
No. 706 and Japanese Patent Application Laid-Open No. 10-87541. The present inventors have disclosed a method for producing alcohol (2) in JP-A-10-248593. The compounds shown below can be produced by these methods or by combining with known synthetic methods.

[0022]

The general method for producing compound (1) is as follows. First, a method for producing the compound (1) in which R ¹ is alkoxy or alkanoyloxy will be described. An optically active ester (Ph1) is synthesized by an ester reaction between a p-bromobenzoic acid derivative and an optically active alcohol. Dicyclohexylcarbodiimide or 1
A condensing agent such as -ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride is used. This ester (Ph1) is used for cross-coupling in the production process of compounds (1-1a) and (1-2a).

[0024]

The fluorene (a) is acetylated by a Friedel-Crafts reaction and further oxidized by a Bayer-Villiger reaction to obtain 2-acetoxyfluorene (b).
Compound (b) is brominated and further hydrolyzed to give 2-bromo-7-hydroxyfluorene (c). Compound (c) is reacted with an alkyl halide or alkanoyl chloride in the presence of a suitable base such as sodium hydroxide, potassium hydroxide, sodium hydride, triethylamine, pyridine or the like to obtain compound (d).

Compound (d) is cross-coupled with trimethylsilylacetylene in the presence of a palladium catalyst, followed by detrimethylsilylation to obtain ethynylfluorene derivative (e). The compound (e) is cross-coupled with the previously synthesized optically active p-bromobenzoic acid derivative (Ph1) in the presence of a palladium catalyst to give a compound (1-1a) wherein R ³ is alkyl or alkanoyl.
Get. Compound (1-1a) is hydrogenated to give compound (1a).
-2a) is obtained.

[0027]

Next, a compound (1) wherein R ¹ is alkyl
The manufacturing method of is shown. After acylating fluorene (a) by Friedel-Crafts reaction, the acyl group is reduced with hydrazine to obtain 2-alkylfluorene. Bromination of 2-alkylfluorene gives 2-alkyl-7-bromofluorene. Thereafter, the above-described method is followed. That is, R ¹ is obtained by the procedure of cross-coupling with trimethylsilylacetylene, hydrolysis, and cross-coupling with an optically active p-bromobenzoic acid derivative (Ph1).
Are compounds (1-1) and (1-2).

[0029]

The compounds, liquid crystal compositions and liquid crystal display devices of the present invention will be described in more detail with reference to the following examples. The compounds described in Examples 1 to 8 and the compounds which can be produced according to the production methods described in the Examples and the above are represented by the structural formulas of Compounds [1] to [150]. The measurement of the physical properties was performed by the following method. Phase transition temperature: The sample was placed on a slide glass, covered with a cover glass, and then placed on a hot stage. Sample at 1 ° C
The phase transition temperature was observed with a deflection microscope while heating at a rate of / min. The unit of temperature is ° C. In the phase transition, N is a nematic phase, SA is a smectic A phase, SC is a smectic C phase, SC ^* is a chiral smectic C phase, and SCA ^*.
Indicates an antiferroelectric phase, SCγ ^* indicates a ferrielectric phase, SX indicates an unidentified smectic phase, and Iso indicates a clearing point. Melting point: 1 ° C./m using differential scanning calorimetry (DSC)
The sample was heated in and the melting point was measured.

Threshold voltage: One of a pair of substrates obtained by coating a polyimide substrate with a polyimide-based alignment film on a glass substrate provided with a transparent electrode was rubbed to face each other to form a cell having an electrode spacing of 5 μm. . A sample in an isotropic liquid phase was injected into this cell and then slowly cooled to prepare an antiferroelectric liquid crystal display device in which the sample was an SCA ^* phase. The optical response and applied voltage when a 50 mHz triangular wave was applied between the electrodes on the upper and lower substrates of the display element were observed with a two-phenomenon oscilloscope. A voltage sufficiently higher than the threshold was applied to the electrode, and the threshold voltage at the phase transition between the antiferroelectric phase and the ferroelectric phase was measured from the change in the optical response. Optical response: A sample was injected into an alignment-treated cell having an electrode spacing of 2 μm, and measured from a change in transmitted light intensity when a 1 kHz rectangular wave having a Vpp of 20 V (plus or minus 10 V) was applied. .

Embodiment 1 Preparation of Compound [8] First Stage: 150 g of fluorene in dichloromethane (1
L) Cool the solution to 0 ° C and dry anhydrous aluminum chloride 126
g was added little by little. Further, a solution of 74 g of acetyl chloride in dichloromethane (400 ml) was added dropwise, and the mixture was stirred for 1 hour while maintaining 0 ° C. The reaction mixture was washed with ice 6
The mixture was poured into 1 L of N hydrochloric acid, and the precipitated solid was separated by filtration. After drying, this was recrystallized from toluene to obtain 165 g of 2-acetylfluorene. Melting point: 12
9 ° C.

Second stage: 2-acetylfluorene 165
g, formic acid 320 g, and acetic anhydride 120 g in dichloromethane (1 L), sulfuric acid 40 ml was added, and then hydrogen peroxide water 120 ml was added dropwise. After stirring at room temperature for 30 minutes, the mixture was heated to 40 ° C. and further stirred for 5 hours. 1 L of water was added, and the dichloromethane layer was separated, and washed with a saturated aqueous solution of sodium carbonate, an aqueous solution of sodium hydrogen sulfite, and water in that order. After drying over anhydrous magnesium sulfate,
Concentration gave a solid. This was recrystallized from a mixed solvent of heptane and ethyl acetate 1: 1 to obtain 149 g of 2-acetoxyfluorene. Melting point: 130 [deg.] C.

Third step: 330 ml of acetic acid and 11 of acetic anhydride
70 g of 2-acetoxyfluorene was added to 0 ml of the solution and dissolved by heating to 65 ° C. Bromine 1 in this solution
25 g was added dropwise in 40 minutes, and the mixture was further stirred for 1 hour.
The reaction mixture was poured into 1 L of water, and the precipitated crystals were collected by filtration. The dried crystals were recrystallized from a mixed solution of 400 ml of ethanol and 300 ml of ethyl acetate to obtain 69 g of 2-
Bromo-7-acetoxyfluorene was obtained. Melting point: 13
0 ° C.

Fourth step: A mixture of 69 g of 2-bromo-7-acetoxyfluorene, 9 g of lithium hydroxide and 350 ml of ethylene glycol was refluxed for 1 hour. The reaction mixture was poured into 300 ml of 6N hydrochloric acid, and then 350 ml of ethyl acetate was added.
Extracted with l. The solution was washed with a saturated aqueous solution of sodium carbonate and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was recrystallized from chloroform to obtain 40 g of 2-bromo-7-hydroxyfluorene. Melting point: 183-184C.

Fifth step: 7 g of 2-bromo-7-hydroxyfluorene, 8 g of dodecyl bromide, 4.4 potassium carbonate
g and 30 ml of dimethylformamide were refluxed for 3 hours. 6N hydrochloric acid was added to the reaction mixture, and the mixture was extracted with toluene. After washing the solution with water, it was dried over anhydrous magnesium sulfate and concentrated. The residue was recrystallized from acetone to give 11
g of 2-bromo-7-dodecyloxyfluorene was obtained. Phase transition temperature: Cr85 SA92 Iso.

Sixth stage: 8 g of 2-bromo-7-dodecyloxyfluorene, 3.5 g of trimethylsilylacetylene
g, 0.12 g of dichlorobis (triphenylphosphine) palladium, 0.03 g of copper iodide, 0.09 g of triphenylphosphine, and 100 ml of triethylamine were refluxed for 3 hours. After the reaction mixture was filtered to remove insolubles, triethylamine was distilled off under reduced pressure. The residue was purified by silica gel column chromatography using toluene as an eluting solvent to obtain 7.6 g of 2-dodecyloxy-7-trimethylsilylethynylfluorene. Melting point: 80 ° C.

Step 7: 7.6 g of 2-dodecyloxy-7-trimethylsilylethynylfluorene, 0.3 g of sodium hydroxide, 4 ml of water, 100 parts of tetrahydrofuran
The ml mixture was stirred at 60 ° C. for 8 hours. Water was added to the reaction mixture to terminate the reaction. The mixture was extracted with ethyl acetate, and the solution was dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent was purified by silica gel column chromatography in which the eluting solvent was toluene, and further recrystallized from ethanol to obtain 5.2 g of 2-dodecyloxy-ethanol.
7-Ethynylfluorene was obtained. Phase transition temperature: Cr 7
4 SA 101Iso.

Step 8: 150 g of p-bromobenzoic acid,
(R) -2-octanol (optical purity 99% ee or more)
A solution of 95 g of dimethylaminopyridine 1 g in methylene chloride (1.5 L) was cooled in an ice bath. 166
g of dicyclohexylcarbodiimide was added in several portions, and the mixture was stirred at room temperature for 24 hours. After removing the insoluble matter by filtration, the residue obtained by concentration was purified by silica gel column chromatography in which the eluting solvent was toluene, and further distilled under reduced pressure to obtain 130 g of (R) -p.
-1-methylheptyl bromobenzoate was obtained. boiling point:
(1.33 hPa) 133-140 ° C.

Ninth step: 1.5 g of 2-dodecyloxy-7-ethynylfluorene, 1.3 g of (R) -p-bromobenzoic acid = 1-methylheptyl, 0.03 g of dichlorobis (triphenylphosphine) palladium, iodine A mixture of 0.007 g of copper chloride, 0.02 g of triphenylphosphine and 50 ml of triethylamine was refluxed for 3 hours. Insoluble matters were removed by filtration, and triethylamine was distilled off under reduced pressure. The residue was purified by silica gel column chromatography in which the elution solvent was toluene, and recrystallized twice from acetone to obtain 1.5 g of compound [8]. The phase transition temperature is shown on the right side of the structural formula of compound [8].

Embodiment 2 FIG. Production of compound [68] 0.5 g of compound [8] was added to 25 ml of terahydrofuran.
0.02 g of palladium carbon was added, and hydrogen was absorbed at normal pressure. After 2 hours, the absorption of hydrogen ceased, so the reaction mixture was filtered to remove the catalyst and the solvent was distilled off.
The residue was recrystallized twice from acetone to obtain 0.4 g of compound [68]. The phase transition temperature is shown on the right side of the structural formula of compound [68].

Embodiment 3 FIG. Preparation of Compound No. [47] First step: 1 g of 4-bromo-2-fluorobenzoic acid,
1 g of dicyclocarbodiimide was added to a solution of 1 g of (S)-(−)-6-ethoxy-1,1,1-trifluoro-2-hexanol (98% ee optical purity) in dichloromethane (50 ml), and the mixture was stirred at room temperature for 12 hours. Stirred. The insolubles were removed by filtration, and the solution was washed with 6N hydrochloric acid, a saturated aqueous solution of sodium carbonate and water in that order, and dried over anhydrous magnesium sulfate. The residue obtained by evaporating the solvent was purified by silica gel column chromatography, and 0.7 g of (S)-
1-Trifluoromethyl-5-ethoxypentyl 4-bromo-2-fluorobenzoate was obtained.

Second step: 0.65 g of 2-dodecyloxy-7-ethynylfluorene, (S) -4-bromo-2
-1-trifluoromethyl-5-ethoxypentyl fluorobenzoate 0.7 g, dichlorobis (triphenylphosphine) palladium 0.014 g, copper iodide 0.00
Using 4 g, 0.01 g of triphenylphosphine and 30 ml of triethylamine as raw materials,
By the same method as in the step, 0.3 g of compound [47] was obtained. The phase transition temperature is shown on the right side of the structural formula of compound [47].

Embodiment 4 FIG. Preparation of Compound No. [127] 1st Step: 4 g of 2-bromo-7-hydroxyfluorene
To a solution of 20 ml of triethylamine and 50 ml of chloroform was added 4.1 g of tetradecanoyl chloride, and the mixture was refluxed for 3 hours. 50 ml of water was added, and extracted with 50 ml of chloroform. The chloroform extract was washed with 6N hydrochloric acid and a saturated aqueous solution of sodium carbonate, and then dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent was recrystallized from ethanol to obtain 6.2 g of 2-bromo-7-tetradecanoyloxyfluorene. Phase transition temperature: Cr 81
SA 94 Iso.

Second stage: 6.2 g of 2-bromo-7-tetradecanoyloxyfluorene, 2.5 g of trimethylsilylacetylene, 0.18 g of dichlorobis (triphenylphosphine) palladium, 0.05 g of copper iodide, 0 g of triphenylphosphine .13 g, triethylamine 10
0 ml of the mixture was refluxed for 2 hours. Insolubles were removed by filtration, and triethylamine was distilled off. The obtained residue was purified by silica gel column chromatography, and further recrystallized from ethanol to obtain 5.9 g of 2-trimethylsilylethynyl-7-tetradecanoyloxyfluorene. Melting point: 89C.

Third step: A solution of 4.9 g of 2-trimethylsilylethynyl-7-tetradecanoyloxyfluorene in 200 ml of tetrahydrofuran was cooled to -60 ° C., and 25 ml of a 1N solution of tetrabutylammonium fluoride in tetrahydrofuran was added thereto for 1 hour. Stirred. −
The temperature was raised to 30 ° C., 25 ml of water was added, the mixture was slowly brought to room temperature, and the mixture was further stirred for 2 hours. Toluene 10
The mixture was extracted with 0 ml, washed with 6N hydrochloric acid and a saturated aqueous solution of sodium carbonate, and dried over anhydrous magnesium sulfate. Purification by silica gel column chromatography and recrystallization from ethanol gave 3.7 g of 2-ethynyl-7-tetradecanoyloxyfluorene. Phase transition temperature: Cr 74
SX 95 Iso.

Fourth stage: A mixture of 5 g of 4-bromo-2-fluorobenzoic acid, 3 g of (R) -2-octanol and 50 ml of dichloromethane was cooled to 0 ° C., and 5.7 g of dicyclohexylcarbodiimide and 0.5 g of dimethylaminopyridine were added. 1 g was added, and the mixture was further stirred at room temperature for 12 hours.
Water was added for liquid separation, and the dichloromethane layer was dried over anhydrous magnesium sulfate. The residue obtained by evaporating the solvent was purified by silica gel column chromatography in which the eluting solvent was toluene, and 5.4 g of (R) -4-bromo-2- was used.
1-Methylhexyl fluorobenzoate was obtained.

Fifth step: 0.7 g of 2-ethynyl-7-tetradecanoyloxyfluorene, 0.56 of 1-methylhexyl (R) -4-bromo-2-fluorobenzoate
g, dichlorobis (triphenylphosphine) palladium 0.012 g, copper iodide 0.0032 g, triphenylphosphine 0.009 g, triethylamine 30 ml
Was used to obtain a compound [127] in the same manner as in the ninth step of Example 1. The phase transition temperature of the compound [12
7] on the right side of the structural formula.

Embodiment 5 FIG. Production of Compound [136] 0.5 g of Compound [127], 0.02 of palladium carbon
g, a solution of 25 ml of terahydrofuran was absorbed with hydrogen at normal pressure. After two hours, the absorption of hydrogen stopped.
The reaction mixture was filtered to remove the catalyst, and the solvent was distilled off. The residue was recrystallized twice from acetone to obtain 0.4 g of compound [136]. The phase transition temperature of the compound [13
6] on the right side of the structural formula.

Embodiment 6 FIG. Production of Compound [16] First Step: 102 g of fluorene in dichloromethane (1
L) Cool the solution to 0 ° C and add anhydrous aluminum chloride 105
g, then add 100 g of octanoyl chloride
Was added dropwise. After stirring at 0 ° C for 3 hours,
The reaction mixture was poured into 1 L of 6N hydrochloric acid. After extraction with dichloromethane and drying over anhydrous magnesium sulfate, the solvent was distilled off to obtain a solid. This was recrystallized from a mixed solvent of heptane and ethyl acetate to obtain 158 g of 2-octanoylfluorene.

Second stage: 2-octanoylfluorene 1
After 58 g and 1 L of diethylene glycol were added to 100 ° C. to form a solution, 73 g of potassium hydroxide and then 65 g of hydrazine were added. The reaction mixture was heated and stirred for 6 hours until the temperature of the reaction mixture reached 250 ° C. while removing water with a Dean Stark. After adding water and extracting with diethyl ether, the extract layer was washed with water and dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent was recrystallized from ethanol,
3 g of 2-octylfluorene were obtained. Melting point: 64-6
6 ° C.

Third stage: 10 g of 2-octylfluorene
1.8 ml of bromine was added dropwise to a chloroform (100 ml) solution of, followed by stirring at room temperature for 4 hours. 100 ml of a saturated aqueous solution of sodium carbonate was added, and the chloroform layer was washed with an aqueous solution of sodium thiosulfate and water in that order, and dried over anhydrous magnesium sulfate. The residue was purified by silica gel column chromatography (toluene) and recrystallization (acetone) to give 2-bromo-7-octylfluorene 8
g was obtained. Melting point: 83-85 [deg.] C.

Fourth step: 2-bromo-7-octylfluorene and trimethylsilylacetylene are cross-coupled in the same manner as in the sixth step in Example 1, and the same method as in the seventh step in Example 1 is used. Hydrolysis yielded 3 g of 2-ethynyl-7-octylfluorene. Melting point: 74 [deg.] C.

Fifth step: 0.85 g of 2-ethynyl-7-octylfluorene, 0.93 g of 1-methylheptyl 4-bromobenzoate, 0.02 g of dichlorobis (triphenylphosphine) palladium, 0.006 g of copper iodide,
Compound [16] was obtained in the same manner as in the ninth step of Example 1, using 0.015 g of triphenylphosphine and 50 ml of triethylamine. The phase transition temperature is described on the right side of the structural formula of compound [16].

Embodiment 7 FIG. Production of Compound [76] Compound [16] was hydrogenated in the same manner as in Example 2 to obtain Compound [76]. The phase transition temperature is described on the right side of the structural formula of compound [76]. Compounds [1] to [150] which can be produced according to the production methods described in Examples 1 to 7 and above are shown by structural formulas.

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

Embodiment 8 FIG. Tristable antiferroelectric liquid crystal composition showing clear hysteresis The following composition of antiferroelectric liquid crystal composition (MIX1), (M
IX2) was prepared.

[0071]

The above compositions (MIX1) and (MIX2)
Was uniform without causing phase separation. The compatibility is good. 1 shows the phase transition temperature of this composition. Composition (M
IX1): Cr unknown SCA ^* 110.1 SC ^*
112.7 SA 140.5 Iso. Composition (M
IX2): Cr unknown SCA ^* 95.0 SA1
12.3 Iso. Composition (MIX1) and Compound [MH
FIG. 1 shows the results of measuring the threshold voltage of [POBC] at each temperature. The composition (MIX1) contains the compound [MHPOB]
C] shows a threshold voltage much lower than that of C alone, and its temperature dependence is also very small. MIX1 showed a tri-state optical response with a well-defined threshold.

Embodiment 9 FIG. Thresholdless antiferroelectric liquid crystal composition The following liquid crystal composition (MIX3) was prepared.

[0074]

The phase transition temperature of the composition (MIX3) is shown.
Cr unknown SCA ^* 83.5SA 87.7 Is
o. Figure 2 shows the optical response to a triangular wave voltage at 75 ° C.
Shown in As can be seen from FIG. 2, the composition (MIX3) showed a V-shaped optical response without hysteresis.

[0076]

In many cases, the compound (1) of the present invention exhibits an antiferroelectric phase over a wide temperature range, or has a potential antiferroelectric property even when it does not exhibit an antiferroelectric phase. are doing.
This compound has excellent compatibility when mixed with another antiferroelectric liquid crystal compound, and is sufficiently stable against heat, light, and the like. The antiferroelectric liquid crystal composition containing this compound as a component exhibits a very low threshold value and its temperature dependence is very small, so that a display element having a low driving voltage can be formed.
Since the thresholdless antiferroelectric liquid crystal composition containing the compound of the present invention has no hysteresis and exhibits a V-shaped optical response, gradation display can be easily performed in combination with an active matrix system such as a TFT. Display device can be realized.

[Brief description of the drawings]

FIG. 1 shows a composition (MIX1) and a compound [MHP]
The results of measuring the threshold voltage of OBC] at each temperature are shown.

FIG. 2 shows the optical response of the composition (MIX3) to a triangular wave voltage at 75 ° C.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/141 G02F 1/141 F-term (Reference) 2H088 GA01 HA08 JA20 MA11 MA12 MA13 4H006 AA01 AA04 AB64 BJ50 BM10 BM30 BM71 BM72 BP10 BP30 4H027 BA07 BD01 BD02 BD05 BD08 BD22 DM08

Claims (7)

[Claims] 1. A compound represented by the formula (1). (Wherein, R ¹ is alkyl of 2 to 20 carbon atoms, one -CH ₂ in the alkyl - or not adjacent two -CH ₂ - each independently -O -, - COO -, -
C≡C-, or -CH = CH- may be replaced by, R ² is alkyl of 1 to 10 carbon atoms, methyl in the alkyl may be replaced by trifluoromethyl or fluoromethyl, X is -C≡C- or -CH ₂ CH ₂ - is, a ¹ is 1,4-phenylene or at least one hydrogen, independently, fluorine, chlorine, bromine,
And 1,4-phenylene substituted with at least one of trifluoromethyl and A ² is methyl, ethyl, methyl in which at least one hydrogen is replaced with fluorine, or at least one hydrogen is replaced with fluorine Ethyl, and A ³ is a single bond, -O-, or-
COO-, m is an integer of 0 to 10, and C * represents an asymmetric carbon. ) 2. The compound according to claim 1, wherein in the formula (1), X is —C≡C—. 3. In the formula (1), X represents —CH ₂ CH ₂ —
The compound according to claim 1, which is 4. In the formula (1), R ¹ is alkyl having 2 to 20 carbon atoms, and one of —CH in the alkyl is
_2- is -O-, -COO-, -C≡C-, or -CH
The compound according to claim 1, wherein R ² is linear alkyl having 1 to 10 carbons, A ² is methyl, and A ³ is a single bond. 5. In the formula (1), R ¹ is straight-chain alkyl having 2 to 20 carbon atoms, and one of-
CH ₂ — is —O—, —COO—, —C≡C—, or —
CH = CH-, and R ² has 1 carbon atom.
The compound of claim 1, wherein A ² is trifluoromethyl. 6. A liquid crystal composition containing at least one compound according to claim 1. Description: 7. A liquid crystal display device comprising a liquid crystal composition containing at least one compound according to any one of claims 1 to 5.