JPH0625100A - Antiferroelectric liquid crystal compound - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a display element, etc., independently showing antiferroelectricity in a wide temperature range including a room temperature, comprising a fluorooxybiphenyl-4-carboxylic acid oxycarbonylfluorophenyl ester derivative. CONSTITUTION:2-Fluoro-4-benzyloxybenzoic acid is reacted with (R)-1- trifluoromethyl-5-methoxypentanol of formula I (* is asymmetric carbon atom) in the presence of a dehydrating condensation agent and a basic catalyst to give (R)-2-fluoro-4-bencyloxynenzoic acid-1-trifluoromethyl-5-methoxypentyl ester. This compound is debenzylated in the presence of palladium carbon, etc., as a catalyst and reacted with a 3'-fluoro-4'-undecyloxybiphenyl-4-carboxylic acid of formula III (R is 10-13C alkyl) in the presence of a dehydrating condensation agent, etc., to give the objective optically active compound of formula IV showing antiferroelectricity independently in a wide temperature range including a room temperature.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel antiferroelectric liquid crystal compound. INDUSTRIAL APPLICABILITY The antiferroelectric liquid crystal compound of the present invention is useful as an antiferroelectric liquid crystal material exhibiting a chiral smectic C _A phase having three stable molecular alignment states with excellent fast response.

[0002]

2. Description of the Related Art Currently, display devices using liquid crystal compounds are
It is widely used from the viewpoints of its low voltage drivability, low power consumption, small size and thinness. The antiferroelectric liquid crystal exhibits the third stable state when no electric field is applied, in addition to the two stable states shown by the ferroelectric liquid crystal. Further, it has excellent properties such as having a memory property, few alignment defects, and being able to repair defects by applying an electric field.

Although some of such antiferroelectric liquid crystal compounds are known, there are very few examples which show antiferroelectricity in a region including room temperature in the temperature rising process alone (Japanese Patent Laid-Open No. 131450/1990). Issue). Therefore, at present, a method of decreasing the antiferroelectric property expression temperature to a region of room temperature or lower by compounding has been investigated (Japanese Patent Laid-Open No. 1-213390).

[0004]

The present invention has a molecular structure different from that of the conventionally known antiferroelectric liquid crystal material, and compared with the conventional compound, the antiferroelectric liquid crystal material alone has an antiferroelectric property in a wide temperature range including room temperature. A liquid crystal material having a dielectric property is provided.

[0005]

The present invention has the general formula [I]
And a display device using the antiferroelectric liquid crystal compound represented by the formula (1) and the antiferroelectric liquid crystal compound represented by the general formula (I).

[0006]

[Chemical 2]

(Wherein R is an alkyl group having 10 or 11 carbon atoms) In the above general formula [I], R is 10 or 11 carbon atoms.
Is an alkyl group, that is, a decyl group or an undecyl group, which may be linear or branched.

Examples of the compound represented by the general formula [I] of the present invention include the following compounds. No. 1: (R) -3′-fluoro-4′-decyloxybiphenyl-4-carboxylic acid-3-fluoro-4- (1
-Trifluoromethyl-5-methoxypentyloxycarbonyl) phenyl ester No. 2: (R) -3'-fluoro-4'-undecyloxybiphenyl-4-carboxylic acid-3-fluoro-4-
(1-Trifluoromethyl-5-methoxypentyloxycarbonyl) phenyl ester

(Production Method) The compound represented by the general formula [I] of the present invention can be produced by the method shown in the following reaction scheme. Hereinafter, the reaction formula will be exemplified. In the formula, R
Are the same as those defined in the general formula [I], and the number of [] in the formula represents the upper compound.

[0010]

[Chemical 3]

In the reaction step (1), dicyclohexylcarbodiimide or the like is used as the dehydration condensing agent, and N,
It can be easily carried out by reacting in an organic base such as N-dimethyl-4-aminopyridine or the like in a solvent such as methylene chloride or chloroform. The reaction step (2) is
The debenzylation step can be carried out by a known method such as palladium carbon or the like as a catalyst, ethanol, acetic acid or the like as a solvent, and hydrogenation at atmospheric pressure. The reaction step (3) can be carried out in exactly the same manner as the reaction step (1), and is easily carried out by the general formula [I] which is the object compound of the present invention.
Can be led to the compound of

(Manufacture of Device) When manufacturing a device using the liquid crystal compound of the present invention, a conventional device manufacturing technique using a ferroelectric liquid crystal can be applied. That is, it can be obtained by injecting a liquid crystal compound into a structure in which two transparent substrates each having a transparent electrode and having a surface subjected to an alignment treatment are bonded together with a spacer interposed therebetween. As the material of the alignment film, polyvinyl alcohol, polyimide, SiO, SiO ₂ or the like can be used. Further, as the spacer, silica beads, alumina beads, glass fibers, polymer films, etc. can be used.

[0013]

INDUSTRIAL APPLICABILITY The optically active compound of the present invention has a molecular structure different from that of a conventionally known antiferroelectric liquid crystal material, and, compared with the conventional compound, it has an antiferroelectric property in a wide temperature range including room temperature alone. It shows sex.

[0014]

EXAMPLES The present invention will be described in more detail below with reference to examples. In addition, the measurement of the phase transition temperature and the identification of the phase in the examples were performed by observing the electric field response of DSC and the device manufactured in Example 1 with a polarizing microscope. The abbreviation used to indicate the phase transition temperature (° C); C
ry is the crystalline phase, SmC _A ^* is the chiral smectic C
_A phase, SmC ^* is chiral smectic C phase, Sm
A represents a smectic A phase, and Iso represents an isotropic liquid phase. Further, the upper value represents the phase transition temperature when the temperature was raised at 5 ° C./min, and the lower value represents the phase transition temperature when the temperature was lowered at 5 ° C./min.

(Example 1) (R) -3'-fluoro-4'-undecyloxybiphenyl-4-carboxylic acid-3-fluoro-4- (1-trifluoromethyl-5-methoxypentyloxycarbonyl) Phenyl Ester (Compound No. 2) (1) (R) -2-Fluoro-4-benzyloxybenzoic Acid-1-Trifluoromethyl-5-methoxypentyl Ester Preparation 2-Fluoro-4-benzyloxybenzoic Acid 1 .50 g
(6.10 mmol), 0.95 g (5.01 m) of (R) -1-trifluoromethyl-5-methoxypentanol
mol) and 0.37 g (3.10 mmol) of N, N-dimethylaminopyridine and 20 methylene chloride.
After adding ml and stirring at room temperature, 1.58 g (7.65 mmol) of dicyclohexylcarbodiimide was added,
The reaction was carried out at room temperature for 2 hours.

After completion of the reaction, the precipitated solid matter was filtered off, washed with water, washed with a 5% acetic acid aqueous solution, washed with water, and then dried over anhydrous magnesium sulfate. The desiccant was filtered off and methylene chloride was distilled off to obtain a crude target product. By purifying this by silica gel column chromatography, 1.71 g (4.12 mmol) of the target (R) -2-fluoro-4-benzyloxybenzoic acid-1-trifluoromethyl-5-methoxypentyl ester was obtained. Got

(2) Production of (R) -2-fluoro-4-hydroxybenzoic acid-1-trifluoromethyl-5-methoxypentyl ester (R) -2-fluoro-4 obtained in the above (1). -Benzyloxybenzoic acid-1-trifluoromethyl-5-methoxypentyl ester 1.60 g (3.90 mmo
l) was dissolved in 10 ml of acetic acid, then, under a hydrogen atmosphere, 5
% Palladium carbon 0.39 g was used to react at room temperature for 5 hours. After completion of the reaction, palladium carbon was filtered off and acetic acid was distilled off to obtain a crude target product. By purifying this by silica gel column chromatography, the desired (R) -2-fluoro-4-hydroxybenzoic acid-
1.23 g (3.79 mmol) of 1-trifluoromethyl-5-methoxypentyl ester was obtained.

(3) Production of target compound (Compound No. 2) 97 mg of (R) -2-fluoro-4-hydroxybenzoic acid-1-trifluoromethyl-5-methoxypentyl ester obtained in the above (2) (0.30 mmol),
3'-fluoro-4'-undecyloxybiphenyl-
140 mg (0.36 mmol) of 4-carboxylic acid and 22 mg of N, N-dimethyl-4-aminopyridine
10 ml of methylene chloride was added to (0.18 mmol), and the mixture was stirred at room temperature, then 93 mg (0.45 mmol) of dicyclohexylcarbodiimide was added, and 2
Reacted for hours.

After the completion of the reaction, the precipitated solid matter was separated by filtration, washed with water, washed with a 5% acetic acid aqueous solution, washed with water, and then dried over anhydrous magnesium sulfate. The desiccant was filtered off and methylene chloride was distilled off to obtain a crude target product. This product was purified by silica gel column chromatography to give the desired (R) -3'-fluoro-4'-undecyloxybiphenyl-4-carboxylic acid-3-fluoro-4.
-(1-Trifluoromethyl-5-methoxypentyloxycarbonyl) phenyl ester 190 mg (0.2
7 mmol) was obtained.

¹ H-NMR spectrum (ppm) 0.89 (t, 3H), 1.14-1.53 (m, 20H), 1.80-1.95 (m, 2H),
3.30 (s, 3H), 3.38 (t, 2H), 4.08 (t, 2H), 5.50−5.61 (m, 1
H), 7.06 (t, 1H), 7.16 (d, 2H), 7.40 (t, 2H), 7.70 (d, 2H),
8.06 (t, 1H), 8.25 (d, 2H) IR spectrum (cm ^-1 ) 2860, 2800, 1780, 1770, 1640, 1540, 1436, 1300, 11
50, 1080, 900, 790, 720 Phase transition temperature (℃)

[0021]

[Chemical 4]

(Example 2) (R) -3'-fluoro-4'-decyloxybiphenyl-4-carboxylic acid-3-fluoro-4- (1-trifluoromethyl-5-methoxypentyloxycarbonyl) phenyl Ester (Compound No. 1) The target compound was synthesized in exactly the same manner as in Example 1 and the phase transition temperature was measured. The results are shown below.

Phase transition temperature (° C.)

[0024]

[Chemical 5]

Comparative Example 1 (R) -3'-fluoro-4'-dodecyloxybiphenyl-4-carboxylic acid-3-fluoro-4- (1-trifluoromethyl-5-methoxypentyloxycarbonyl) phenyl Ester The target compound was synthesized and the phase transition temperature was measured in exactly the same manner as in Example 1. The results are shown below.

[0026]

[Chemical 6]

This compound had a higher minimum temperature at which it exhibits antiferroelectricity, as compared with the compounds of Examples.

(Comparative Examples 2 and 3) In the same manner as in Example 1,
The compounds in which R in the following general formula [VI] is shown in Table 1 were synthesized, and the phase transition precursor phenomenon of each compound was measured. The results are shown in Table 1. In each of these compounds, the lower limit temperature exhibiting antiferroelectricity was higher than that of the compound of the example.

[0029]

[Chemical 7]

[0030]

[Table 1]

Claims (1)

[Claims] 1. An antiferroelectric liquid crystal compound represented by the general formula [I]. [Chemical 1] (In the formula, R is an alkyl group having 10 or 11 carbon atoms)