JP2005289881A - Optically active compound and liquid crystal composition containing the compound - Google Patents

Abstract

【選択図】 なし
PROBLEM TO BE SOLVED: To provide a novel optically active compound capable of withstanding a low voltage requirement for the liquid crystal composition and giving a desired helical pitch by adding to the liquid crystal material while maintaining the low viscosity of the liquid crystal composition. And a liquid crystal composition containing the compound, and an electro-optical display element using the liquid crystal composition.
An optically active compound represented by the following general formula (1).
[Chemical 1]

[Selection figure] None

Description

  The present invention comprises a novel optically active compound which has a different optically active group on both sides of the molecule, and can control HTP (helical twist power) only with a single optically active compound, and the compound. The present invention relates to a liquid crystal composition and an electro-optic display element using the liquid crystal composition. The optically active compound is useful as a liquid crystal compound, and the liquid crystal composition is useful for all display elements and electro-optical display elements of all drive systems.

  Liquid crystals are applied as various electro-optical elements and are put into practical use for displays such as watches, calculators, and automobile panels. Most liquid crystal display devices currently in practical use utilize the dielectric alignment effect of twisted nematic liquid crystal or cholesteric liquid crystal. However, recently, other types of liquid crystal display methods have been actively developed, and the STN method, the cholesteric nematic phase transition display method, and the like have been used. All of the liquid crystal compositions used in these liquid crystal display elements are prepared by introducing an optically active substituent into a nematic liquid crystal or adding an optically active substance to adjust the helical pitch to an arbitrary value. There are many.

  Patent Literature 1, Patent Literature 2 and Patent Literature 3 disclose specific optically active compounds, which describe that optically active compounds having various helical pitch values are required in various applications. Yes. For example, an optically active compound having a large HTP is required for a cholesteric liquid crystal, and an optically active compound that provides a helical pitch that does not change even with a temperature change in a nematic liquid crystal, or an optical that can adjust the temperature change of the helical pitch due to a temperature change. There is a need for active compounds and the like.

Japanese Patent No. 2524341 JP 07-258641 A JP 2002-308833 A

  However, it is difficult to obtain a desired helical pitch using only a single optically active compound. When a helical pitch is prepared using a plurality of optically active compounds, the blending ratio may be blurred or the operation may be complicated. There was a problem. Further, in the cholesteric liquid crystal, when the amount of the optically active compound added is increased, there are problems that the temperature range of the liquid crystal composition is narrowed and the viscosity is increased.

  As described above, the problem to be solved is that an optically active compound capable of providing a desired helical pitch only with a single optically active compound when added to a liquid crystal material, and a liquid crystal composition containing the compound Has never been obtained before.

  Accordingly, an object of the present invention is to add a liquid crystal material to withstand a low voltage requirement for the liquid crystal composition and to provide a desired helical pitch while maintaining the low viscosity of the liquid crystal composition. It is an object of the present invention to provide a novel optically active compound, a liquid crystal composition containing the compound, and an electro-optical display element using the liquid crystal composition.

  As a result of intensive studies, the present inventors have found that a novel optically active compound having different optically active groups on both sides of the molecule can regulate HTP with only a single optically active compound. It has been found that it is extremely suitable for achieving the above.

  The present invention has been made based on the above findings, and provides an optically active compound represented by the following general formula (1), a liquid crystal composition containing the compound, and an electro-optic display device using the liquid crystal composition. To do.

  The optically active compound of the present invention is useful as a liquid crystal material used in a liquid crystal composition for all display elements and electro-optical display elements of any driving system.

  Hereinafter, the optically active compound of the present invention, a liquid crystal composition containing the compound, and an electro-optic display device using the liquid crystal composition will be described in detail based on preferred embodiments thereof.

  In the above general formula (1) representing the optically active compound of the present invention, examples of the benzene ring that may be substituted with a halogen atom, an alkyl group, or an alkoxy group include 2-chloro-1,4-phenylene, 3-chloro- 1,4-phenylene, 2,3-dichloro-1,4-phenylene, 2-bromo-1,4-phenylene, 3-fluoro-1,4-phenylene, 2-methyl-1,4-phenylene, 2, 3-dimethyl-1,4-phenylene, 2-ethyl-1,4-phenylene, 3-propyl-1,4-phenylene, 2-methoxy-1,4-phenylene, 2-ethoxy-1,4-phenylene, etc. Examples of the alkyl group having 1 to 18 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, sec-butyl, isobutyl, amyl, isoamyl, and tertiary amyl. Hexyl, 2-hexyl, 3-hexyl, cyclohexyl, 1-methylcyclohexyl, heptyl, 2-heptyl, 3-heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl , Decyl, stearyl and the like, and as the alkoxy group, methyloxy, ethyloxy, propyloxy, isopropyloxy, butyloxy, sec-butyloxy, tert-butyloxy, isobutyloxy, amyloxy, isoamyloxy, tert-amyloxy, hexyloxy, Examples include cyclohexyloxy, heptyloxy, isoheptyloxy, tertiary heptyloxy, n-octyloxy, isooctyloxy, tertiary octyloxy, 2-ethylhexyloxy, and the like. Examples of the group include vinyl, 1-methylethenyl, 2-methylethenyl, propenyl, butenyl, isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, decenyl, pentadecenyl, eicosenyl, tricosenyl and the like. Examples of alkenyloxy groups include vinyloxy, 1 -Methylethenyloxy, 2-methylethenyloxy, propenyloxy, butenyloxy, isobutenyloxy, pentenyloxy, hexenyloxy, heptenyloxy, octenyloxy, decenyloxy, pentadecenyloxy, eicosenyloxy, tricho Examples of acyl groups include acetyl, propionyl, octanoyl, acryloyl, methacryloyl, phenylcarbonyl (benzoyl), phthaloyl, and 4-trifluoro. Romethylbenzoyl, salicyloyl, oxaloyl, 1,4-butanedicarbonyl, dibutylcarbamoyl, tolylenecarbamoyl, hexamethylenedicarbamoyl and the like. As the halogen atom represented by Y, fluorine atom, chlorine atom, bromine atom, An iodine atom etc. are mentioned.

  Specific examples of the optically active compound of the present invention represented by the general formula (1) include the following compound No. Although 1-10 are mentioned, it is not limited to these compounds.

As the optically active compound of the present invention, in the above general formula (1), A and B are 1,4-phenylene, X ₂ is —O—, X ₄ is —COO—, m and n are 1, In particular, A and B are 1,4-phenylene, X ₁ and X ₃ are single bonds, X ₂ is —O—, X ₄ is —COO—, Y is Cl, m and n are 1, p is 0, q Is preferably 5.

  The method for producing the optically active compound of the present invention is not particularly limited, and for example, the optically active compound a can be synthesized by the following synthesis route. It can be synthesized according to the synthesis route.

  The liquid crystal composition of the present invention comprises at least one kind of the optically active compound of the present invention represented by the above general formula (1) and other components (mother liquid crystals), a conventionally known liquid crystal compound or liquid crystal similar compound, or Examples of the mother liquid crystal include compounds represented by the following general formula (2) or a mixture thereof.

Accordingly, specific examples of the compound represented by the general formula (2) include the following compounds. In the following compounds, Y, Y ₁ , Y ₂ and Y ₃ are the same as those in the general formula (2).

  The content of the optically active compound of the present invention represented by the general formula (1) in the liquid crystal composition of the present invention is not particularly limited, but is generally 0.001 in 100 parts by mass of the total liquid crystal composition. It is preferable to make it contain -50 mass parts, especially 0.01-20 mass parts.

  In the present invention, HTP is a product of the reciprocal of the helical pitch p and the reciprocal of the concentration c of the optically active compound, as shown by the following [Equation 1], and represents the magnitude of the helical induction force of the optically active compound. It is a numerical value that represents.

[Equation 1]
HTP = 1 / p ・ 1 / c

  The helical pitch of nematic liquid crystal or cholesteric liquid crystal used in the present invention can be selected according to the purpose of use, but the helical pitch of nematic liquid crystal is in the range of 5 to 300 μm, and the helical pitch of cholesteric liquid crystal is in the range of 0.2 to 0.7 μm. Is preferred.

  The liquid crystal composition containing the optically active compound of the present invention can be sealed in a liquid crystal cell to constitute various electro-optic display elements. Examples of the electro-optic display element include a dynamic scattering (DS) type, a guest-host (GH) type, a twisted nematic (TN) type, a super twisted nematic (STN) type, a thin film transistor (TFT) type, and a thin film diode ( TFD) type, ferroelectric liquid crystal (FLC) type, antiferroelectric liquid crystal (AFLC) type, polymer dispersed liquid crystal (PDLC) type, cholesteric liquid crystal type, vertical alignment (VA) type, in-plane switching (IPS) type, etc. Various display modes can be applied, and various drive methods such as a static drive method, a time-division drive method, an active matrix drive method, and a two-frequency drive method can be applied.

  The electro-optic display element using the optically active compound of the present invention includes a clock, a calculator, a measuring instrument, an automotive instrument, a copying machine, a camera, an OA device, a portable personal computer, a cellular phone, an electronic book, an optical printer head. It can be used for applications such as passive optical elements, sensors, dimming windows, optical shutter elements, and polarization exchange elements.

  Hereinafter, the present invention will be described in more detail with reference to examples and the like. However, the present invention is not limited by the following examples.

[Synthesis Example 1] Compound No. 1 Synthesis of 1 <Step 1> Synthesis of methyl p-hydroxybiphenylcarboxylate The following methyl p-hydroxybiphenylcarboxylate was synthesized as follows according to the reaction formula shown in [Chemical Formula 15].

  Under an argon stream, 100 g (0.47 mol) of p-hydroxybiphenylcarboxylic acid was suspended in 1.6 l of methanol, and 20 ml of concentrated sulfuric acid was added all at once. After stirring at 65 ° C. for 3 hours, the mixture was cooled to 0 ° C. The precipitate was filtered off, washed with 270 ml of cold methanol, and dried to obtain methyl p-hydroxybiphenylcarboxylate as a white solid (yield 100.24 g, purity 99%, yield 94%).

<Step 2> Synthesis of ester intermediate 1 The following ester intermediate 1 was synthesized as follows according to the reaction formula shown in [Chemical Formula 16].

  Under an argon stream, 100.2 g (0.44 mol) of methyl p-hydroxybiphenylcarboxylate obtained in Step 1, 50.0 g (0.48 mol) of (S), (S) -2,4-pentanediol, tri 138.0 g (0.50 mol) of phenylphosphine was dissolved in 870 ml of diethyl ether, and 101.7 g (0.48 mol) of diisopropyl azodicarboxylate was added dropwise at 40 ° C. or lower. After dropping, the mixture was reacted at room temperature for 1 hour, 500 ml of n-hexane was added, and the mixture was cooled to 5 ° C. The precipitate was filtered, washed with 170 ml of a mixed solvent of diethyl ether: n-hexane = 1: 1, and the solvent was distilled off from the filtrate. The ester intermediate 1 was isolated as a colorless amorphous solid by silica gel chromatography using a mixed solvent of acetone: n-hexane = 1: 2 as a developing solvent. (Yield 133.39 g, purity 87.7%, yield 98%)

<Step 3> Synthesis of ester intermediate 2 The following ester intermediate 2 was synthesized as follows according to the reaction formula shown in [Chemical Formula 17].

  Under an argon stream, 133.4 g (0.40 mol) of ester intermediate 1 obtained in Step 2, 157.6 g (0.60 mol) of triphenylphosphine, and 500 ml of carbon tetrachloride were mixed and heated to 80 ° C. to obtain a solid. Precipitated. The mixture was stirred at 80 ° C. for 1 hour, 300 ml of diethyl ether was added and cooled to room temperature, and the solid was filtered off. The filtered solid was washed with 150 ml of diethyl ether, and ester intermediate 2 was isolated as a colorless amorphous solid by silica gel chromatography using acetone: n-hexane = 1: 4 as a developing solvent (yield 128.06 g, (Purity 93.5%, yield 96%).

<Step 4> Synthesis of Carboxylic Acid Intermediate 1 The following carboxylic acid intermediate 1 was synthesized according to the reaction formula shown in [Chemical Formula 18] as follows.

  Under a nitrogen stream, 128.1 g (0.37 mol) of the ester intermediate 2 obtained in Step 3 was suspended in 390 ml of ethanol, and 37.0 g (0.56 mol) of potassium hydroxide and 130 ml of water were added. The mixture was heated to reflux at 78 ° C. for 2 hours and cooled to room temperature. 1.5 l of water and 60 g of concentrated hydrochloric acid were mixed, and the reaction solution was added to the mixture. Washing with water until pH = 7.0 and drying gave carboxylic acid intermediate 1 as a colorless amorphous solid (yield 107.17 g, purity 95% <, yield 90%).

<Step 5> Compound No. Synthesis of Compound No. 1 1 was synthesized as follows according to the reaction formula shown in [Chemical Formula 19].

4.66 g (0.015 mol) of carboxylic acid intermediate 1 obtained in Step 4, 1.88 g (0.014 mol) of R-(−)-2-octanol, 4- (N, N-dimethylamino) pyridine When 0.089 g (7.3 × 10 ⁻⁴ mol) and 93.20 g of chloroform were mixed and 2.98 g (0.014 mol) of dicyclohexylcarbodiimide dissolved in 7.45 g of chloroform was added dropwise at room temperature, a white solid was precipitated. The mixture was stirred at room temperature for 1.5 hours and cooled to 0 ° C. The solid was filtered off and the filtrate was concentrated to give a crude product. A colorless liquid was isolated by silica gel chromatography using ethyl acetate: n-hexane = 1: 4 as a developing solvent (yield 2.48 g, purity 99.5%, yield 40%).

The obtained colorless liquid has the following infrared absorption spectrum (IR) measurement result and ¹ H-NMR measurement result. 1 was confirmed.

[IR] (cm ^-1 )
2930, 2858, 1713, 1607, 1582, 1562, 1523, 1454, 1377, 1277, 1246, 1186, 1138, 1111, 1082, 829, 773
[ ¹ H-NMR] (ppm)
8.1 (d: 2H), 7.6-7.5 (dd: 4H), 7.0 (d: 2H), 5.1 (m: 1H), 4.7 (m: 1H), 4 .3 (m: 1H), 1.3-1.1 (m: 24H)

[Synthesis Example 2] Compound No. Synthesis of Compound No. 2 According to the reaction formula shown in [Chemical Formula 20], 2 was synthesized as follows.

4.90 g (0.015 mol) of carboxylic acid intermediate 1 obtained in Step 4 of Synthesis Example 1, 2.00 g (0.015 mol) of S-(+)-2-octanol, 4- (N, N- Dimethylamino) pyridine (0.094 g (7.7 × 10 ⁻⁴ mol)) and dichloromethane (98.00 g) are mixed, and 3.17 g (0.015 mol) of dicyclohexylcarbodiimide dissolved in 7.93 g of dichloromethane is added dropwise at room temperature to give a white solid. Precipitated. The mixture was stirred at room temperature for 1.5 hours and cooled to 0 ° C. The solid was filtered off and the solvent was distilled off from the filtrate. A colorless liquid was isolated by silica gel chromatography using ethyl acetate: n-hexane = 1: 4 as a developing solvent (yield 3.53 g, purity 99.5% <, yield 57%).

The IR measurement result and ¹ H-NMR measurement result of the obtained colorless liquid are as follows, and the colorless liquid is the target compound No. 1. 2 was confirmed.

[IR] (cm ^-1 )
2932, 2858, 1713, 1605, 1562, 1523, 1497, 1454, 1377, 1277, 1246, 1184, 1111, 1034, 829, 772
[ ¹ H-NMR] (ppm)
8.1 (d: 2H), 7.8-7.5 (dd: 4H), 7.0 (d: 2H), 5.2 (m: 1H), 4.8 (m: 1H), 4 .3 (m: 1H), 1.5-1.3 (m: 24H)

[Synthesis Example 3] Compound No. Synthesis of compound No. 3 According to the reaction formula shown in [Chemical Formula 21], 3 was synthesized as follows.

  Under a nitrogen stream, 8.19 g (0.026 mol) of carboxylic acid intermediate 1 obtained in Step 4 of Synthesis Example 1, 2.27 g (0.026 mol) of (S) -2-methylbutanol, 4- (N , N-dimethylamino) pyridine (0.16 g, 1.3 mmol) and 164 g of dichloromethane were mixed, and 5.30 g (0.027 mol) of dicyclohexylcarbodiimide dissolved in 13.25 g of dichloromethane was added dropwise at room temperature. Stir. It cooled to 0 degreeC, filtered and the solvent was distilled off. A solid was isolated by silica gel chromatography using ethyl acetate: n-hexane = 1: 2 as a developing solvent, and crystallized from a mixed solvent of methanol: ethyl acetate = 4: 1 to obtain a colorless liquid (yield 11. 27 g, purity 99.7%, yield 71%).

The obtained liquid was subjected to IR analysis and ¹ H-NMR analysis to obtain the target compound No. 1. 3 was identified. The analysis results are shown below.

[IR] (cm ^-1 )
2966, 1705, 1601, 1524, 1497, 1381, 1273, 1246, 1192, 1115, 1076, 826, 775
[ ¹ H-NMR] (ppm)
8.1 (d: 2H), 7.6 (d: 2H), 7.5 (d: 2H), 7.0 (d: 2H), 4.7 (m: 1H), 4.3 (m : 1H), 4.2 (d: 2H), 2.1-0.9 (m: 19H)

[Synthesis Example 4] Compound No. <Step 1> Synthesis of Carboxylic Acid Intermediate 2 The following carboxylic acid intermediate 2 was synthesized as follows according to the reaction formula shown in [Chemical Formula 22].

  Under a nitrogen stream, 304.30 g (2.0 mol) of methyl-p-hydroxybenzoate, 253.16 g (2.0 mol) of benzyl chloride, 359.35 g (2.6 mol) of potassium carbonate and 1538 g of ethanol were mixed and heated for 3 hours. Refluxed. After cooling to room temperature, 1022 g of 10% HCl aqueous solution was added dropwise to stop the reaction. After adding 1280 g of toluene and washing with water three times, the oil layer was extracted and the solvent was distilled off to obtain a solid. 485 g of the obtained solid, 168.33 g (3.0 mol) of potassium hydroxide, 1735 g of ethanol and 457 g of water were mixed and heated under reflux for 1 hour. After cooling to room temperature, the reaction was stopped by dropwise addition of a mixture of 313 g of 50% HCl and 2283 g of water. The solid was filtered off and washed with water to obtain carboxylic acid intermediate 2 as a solid (yield 412.81 g, purity 99.6%, yield 90%).

<Step 2> Synthesis of ester intermediate 3 The following ester intermediate 3 was synthesized according to the reaction formula shown in [Chemical Formula 23] as follows.

  Under a nitrogen stream, 20.83 g (0.091 mol) of the carboxylic acid intermediate 2 obtained in Step 1 and 155.4 g of toluene were mixed, and 2-3 drops of dimethylformamide was added. 16.29 g (0.14 mol) of thionyl chloride was added dropwise, and the mixture was stirred at 60 ° C. for 2 hours. After distilling off half of the thionyl chloride, 50 g of toluene and 0.56 g (4.5 mmol) of dimethylaminopyridine were added, and 12.28 g (0.095 mol) of (R) -2-octanol was added dropwise to precipitate a white solid. . Subsequently, 10.16 g (0.1 mol) of triethylamine was added dropwise, and the mixture was heated to reflux for 2.5 hours. The oil layer was extracted by adding 150 g each of 10% HCl and a saturated aqueous sodium hydrogen carbonate solution followed by water, and the solvent was distilled off. A solid was isolated by silica gel column chromatography using toluene as a developing solvent, and crystallized from a mixed solvent of methanol: ethyl acetate = 3: 1 to obtain ester intermediate 3 as a white solid (yield 26.16 g, (Purity 99.5%, yield 84%).

<Step 3> Synthesis of ester intermediate 4 The following ester intermediate 4 was synthesized according to the reaction formula shown in [Chemical Formula 24] as follows.

26.10 g (0.077 mol) of ester intermediate 3 obtained in Step 2, 1.92 g of Pd—C (50% H ₂ O) and 48.10 g of tetrahydrofuran were mixed and stirred overnight in a hydrogen stream. Celite filtration was performed, and the solvent was distilled off from the filtrate to obtain ester intermediate 4 as a colorless liquid (yield 19.04 g, purity 99.5%, yield 99%).

<Step 4> Compound No. Synthesis of Compound No. 4 4 was synthesized as follows according to the reaction formula shown in [Chemical Formula 25].

  Under a nitrogen stream, 8.68 g (0.027 mol) of the carboxylic acid intermediate 1 obtained in Step 4 of Synthesis Example 1 and 6.81 g of the ester intermediate 4 obtained in Step 3 of Synthesis Example 4 (0. 027 mol), 0.17 g (1.3 mmol) of 4- (N, N-dimethylamino) pyridine and 130.5 g of dichloromethane were mixed, and 5.82 g (0.028 mol) of dicyclohexylcarbodiimide dissolved in 14.65 g of dichloromethane was mixed at room temperature. And stirred at room temperature for 2 hours. The solution was cooled to 0 ° C., filtered and the solvent was distilled off to obtain a solid. The solid was isolated by silica gel column chromatography using ethyl acetate: n-hexane = 1: 2 as a developing solvent, and crystallized from a mixed solvent of methanol: ethyl acetate = 1: 1 to obtain a white solid (yield) 7.12 g, purity 99.7%, yield 75%).

The obtained solid was subjected to IR analysis and ¹ H-NMR analysis to obtain the target compound No. 1. 4 was identified. The analysis results are shown below.

[IR] (cm ^-1 )
2974, 2927, 2855, 1736, 1713, 1601, 1562, 1527, 1497, 1381, 1273, 1188, 1161, 1065, 887, 764
[ ¹ H-NMR] (ppm)
8.2 (d: 2H), 8.1 (d: 2H), 7.7 (d: 2H), 7.6 (d: 2H), 7.3 (d: 2H), 7.0 (d : 2H), 5.2 (m: 1H), 4.7 (m: 1H), 4.3 (m: 1H), 2.0-0.8 (m: 26H)

[Synthesis Example 5] Compound No. Synthesis of 5 <Step 1> Synthesis of ester intermediate 5 The following ester intermediate 5 was synthesized according to the reaction formula shown in [Chemical Formula 26] as follows.

  Under an argon stream, 100.2 g (0.44 mol) of methyl p-hydroxybiphenylcarboxylate obtained in Step 1 of Synthesis Example 1 and 50.0 g of (R), (R) -2,4-pentanediol (0. 48 mol) and 138.0 g (0.50 mol) of triphenylphosphine were dissolved in 870 ml of diethyl ether, and 101.7 g (0.48 mol) of diisopropyl azodicarboxylate was added dropwise at 40 ° C. or lower. After dropping, the mixture was reacted at room temperature for 1 hour, 500 ml of n-hexane was added, and the mixture was cooled to 5 ° C. The precipitate was filtered, washed with 170 ml of a mixed solvent of diethyl ether: n-hexane = 1: 1, and the solvent was distilled off from the filtrate. The ester intermediate 5 was isolated as a colorless amorphous solid by silica gel chromatography using a mixed solvent of acetone: n-hexane = 1: 2 as a developing solvent. (Yield 133.41 g, purity 88.7%, yield 98%)

<Step 2> Synthesis of ester intermediate 6 The following ester intermediate 6 was synthesized as follows according to the reaction formula shown in [Chemical Formula 27].

  Under an argon stream, 133.4 g (0.40 mol) of ester intermediate 5 obtained in Step 1, 157.6 g (0.60 mol) of triphenylphosphine and 500 ml of carbon tetrachloride were mixed and heated to 80 ° C. to obtain a solid. Precipitated. The mixture was stirred at 80 ° C. for 1 hour, 300 ml of diethyl ether was added and cooled to room temperature, and the solid was filtered off. The filtered solid was washed with 150 ml of diethyl ether, and the ester intermediate 6 was isolated as a colorless amorphous solid by silica gel chromatography using acetone: n-hexane = 1: 4 as a developing solvent (yield 128.1 g, (Purity 93.7%, yield 96%).

<Step 3> Synthesis of Carboxylic Acid Intermediate 3 The following carboxylic acid intermediate 3 was synthesized according to the reaction formula shown in [Chemical Formula 28] as follows.

  Under a nitrogen stream, 128.1 g (0.37 mol) of the ester intermediate 6 obtained in Step 2 was suspended in 390 ml of ethanol, and 37.0 g (0.56 mol) of potassium hydroxide and 130 ml of water were added. The mixture was heated to reflux at 78 ° C. for 2 hours and cooled to room temperature. 1.5 l of water and 60 g of concentrated hydrochloric acid were mixed, and the reaction solution was added to the mixture. Washing with water until pH = 7.0 and drying gave carboxylic acid intermediate 3 as a colorless amorphous solid (yield 107.21 g, purity 95% <, yield 90%).

<Step 4> Compound No. Synthesis of Compound No. 5 5 was synthesized according to the reaction formula shown in [Chemical 29] as follows.

  9.64 g (0.03 mol) of the carboxylic acid intermediate 3 obtained in Step 3 and 7.57 g (0.03 mol) of the ester intermediate 4 obtained in Step 3 of Synthesis Example 4 under a nitrogen stream -(N, N-dimethylamino) pyridine (0.19 g, 1.4 mmol) and dichloromethane (145 g) were mixed, and dicyclohexylcarbodiimide (6.47 g, 0.031 mol) dissolved in dichloromethane (16.28 g) was added dropwise at room temperature. Stir for 2 hours. The solution was cooled to 0 ° C., filtered and the solvent was distilled off to obtain a solid. The solid was isolated by silica gel column chromatography using ethyl acetate: n-hexane = 1: 2 as a developing solvent, and crystallized from a mixed solvent of methanol: ethyl acetate = 1: 1 to obtain a white solid (yield) 7.93 g, purity 99.8%, yield 75%).

The obtained solid was subjected to IR analysis and ¹ H-NMR analysis to obtain the target compound No. 1. 5 was identified. The analysis results are shown below.

[IR] (cm ^-1 )
2972, 2927, 2855, 1734, 1713, 1601, 1562, 1527, 1497, 1381, 1273, 1188, 1161, 1065, 887, 763
[ ¹ H-NMR] (ppm)
8.2 (d: 2H), 8.1 (d: 2H), 7.7 (d: 2H), 7.6 (d: 2H), 7.4 (d: 2H), 7.0 (d : 2H), 5.2 (m: 1H), 4.7 (m: 1H), 4.3 (m: 1H), 1.9-0.9 (m: 26H)

[Example 1]
1 part by weight of each of the optically active compounds of the present invention synthesized according to the above Synthesis Examples 1 to 5 is mixed with 100 parts by weight of a typical nematic liquid crystal ZLI-1565 manufactured by Merck Co., Ltd. And the direction of the helix was examined. Further, 30 ° C. pitch at the (P ₃₀₎ and 60 ° C. The (P ₆₀₎ were measured, respectively, was determined the ratio (P ₆₀ / P _30). The measurement results are shown in Table 1.

[Example 2]
Compound No. 13.3 parts by weight of 2 was mixed with 100 parts by weight of ZLI-1565, injected into a parallel alignment cell having a cell thickness of 10 μm, and the selective reflection wavelength was measured with a spectrophotometer, which was 583 nm.

[Comparative Example 1]
The following comparative compound No. 25.3 parts by weight of 1 was mixed with 100 parts by weight of ZLI-1565, injected into a parallel alignment cell having a cell thickness of 10 μm, and the selective reflection wavelength was measured with a spectrophotometer, which was 651 nm.

The following could be confirmed from the above Examples and Comparative Examples. When the optically active compound of the present invention is added to a liquid crystal material, a desired helical pitch can be provided by adding a single optically active compound. Further, the optically active compound of the present invention can be used as a chiral dopant for cholesteric liquid crystal because it can obtain a selected wavelength in the visible light region by adding a small amount.

Claims (4)

An optically active compound represented by the following general formula (1).

The optically active compound according to claim 1, wherein, in the general formula (1), A and B are 1,4-phenylene, X ₂ is -O-, X ₄ is -COO-, and m and n are 1.   A liquid crystal composition comprising at least one optically active compound according to claim 1 or 2.   An electro-optic display element comprising a liquid crystal cell filled with the liquid crystal composition according to claim 3.