JP2528440B2 - Optically active substance and liquid crystal composition containing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel optically active substance and a liquid crystal composition containing the same.

[0002]

BACKGROUND ART As various optical elements characterized by having optical activity, many are known as exemplified below.

1) Utilizing the cholesteric / nematic phase transition effect in the liquid crystal state (JJ Wys)
oki, A .; Adams and W.D. Haas; "Physical Review Letters" (Phys. Rev.
Lett. ), 20, 1024 (1968)), 2) Utilizing the white Taylor type guest-host effect in a liquid crystal state (DL White and and
G. N. Taylor; "Journal of Applied Physics" (J. Appl. Phys.), 4
5 , 4718 (1974)), 3) Chiral smectic C phase, H in liquid crystal state
Using the ferroelectric effect of N-phase, F-phase, I-phase, G-phase, K-phase, and J-phase (NA Clark and STL
agerwall; “Applied Physics Letters” (Appl. Phys. Lett.), 36 , 89.
9 (1980)), 4) A liquid crystal compound having a cholesteric phase is fixed in a matrix to utilize its selective scattering property to be used as a notch filter or a bandpass filter (FJ Kahn; "Applied
Physics Letters "(Appl. Phys. Let
t. ), 18, 231 (1971)), which is used as a circularly polarized beam splitter utilizing circular polarization characteristics (SD Jacobs, SPIE, 37, 98 (19).
81)); and so on.

Although detailed description of each method is omitted, all of them are important as a display element or a modulation element.

Further, by adding a very small amount to a nematic liquid crystal composition for twisted nematic (TN) type display device, the occurrence of stripe pattern (reverse domain) on the display surface is prevented and the uniformity of the display is increased. It can be effectively used for things.

Conventionally, 2-methylbutanol, secondary octyl alcohol, secondary butyl alcohol, chloride are used as optically active intermediates for synthesizing functional materials required for optical elements characterized by having optical activity. Known are p- (2-methylbutyl) benzoic acid, secondary phenethyl alcohol, amino acid derivatives, camphor derivatives, cholesterol derivatives and the like.

However, these have the following problems. The optically active chain hydrocarbon derivative is difficult to change in structure, and is very expensive except for a part thereof. Amino acid derivatives are relatively inexpensive and easy to change in structure, but the hydrogen groups of amines are chemically active, and hydrogen bonds and chemical reactions easily occur, which limits the properties of functional materials. It is easy to fall. Camphor derivative
Cholesterol derivatives are difficult to change in structure and
The steric hindrance is likely to adversely affect the properties of the functional material.

The above-mentioned drawbacks have been a major limitation in developing various materials.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points. That is, the present invention aims to provide a compound which can be bound to a functional material intermediate having an appropriate intermolecular force and shape without impairing the optical activity, and which can be freely designed in terms of molecular design. And

Further, according to the present invention, it is easy to change the length of the alkyl group. Arnold,
"Zeit Schriftfür Physica Rische Chemie" (Z. Phys. Chem.), 226, 14
6 (1964), a liquid crystal compound capable of controlling the type and temperature range of a liquid crystal phase developed in a liquid crystal state, and a liquid crystal composition containing the compound as at least one compounding component are provided. The purpose is to
Further, the present invention provides LB (Langmuir-Blodg).
The purpose of the present invention is to provide a compound capable of easily controlling a hydrophobic group and stably forming a film when a monomolecular cumulative film is produced by the ett) film method.

[0011]

SUMMARY OF THE INVENTION The present invention has the general formula (II)

[0012]

Embedded image (R ^* represents an alkyl group having an asymmetric carbon atom and having 4 to 12 carbon atoms) and an optically active bis (4-alkylphenyl) disulfide and a liquid crystal composition containing at least one of them as a compounding component. I will provide a.

Since the compound represented by the general formula (II) has an asymmetric carbon and a thiol group through a benzene ring, it does not lose its optical activity and thus has a thiolcarboxylic acid ester bond, a sulfide bond or a sulfoxide. Since various derivatives can be easily synthesized by conjugation and the like, the compound is expected to be available in a very wide range. However, to date, the formula (I
No optically active compound as shown in I) is known.

As a result of intensive studies based on the above findings, the present inventors succeeded in synthesizing the compound represented by the general formula (II) and completed the present invention.

The novel optically active substance represented by the general formula (II) of the present invention is effective in preventing a reverse domain in a twisted nematic (TN) type cell by adding it to a nematic liquid crystal. When added to nematic liquid crystal, it can be used as a chiral nematic liquid crystal in a phase transition type liquid crystal element or a white Taylor type guest / host type liquid crystal element.

In a device that utilizes the ferroelectricity of the chiral smectic phase, its characteristics can be improved by adding it to the liquid crystal composition.
A smectic liquid crystal having the following general formula (I
By adding the optically active substance represented by I), it becomes possible to utilize it as a ferroelectric chiral smectic phase.

[0017]

Embedded image

[0018]

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As described above, the novel optically active substance represented by the general formula (II) of the present invention is very effective as a material used for improving the performance of a ferroelectric liquid crystal device or a TN type liquid crystal device. is there.

[0020]

DETAILED DESCRIPTION OF THE INVENTION First, a method for synthesizing an optically active substance of the present invention will be described.

In order to produce the optically active 4-alkylbenzenethiol represented by the general formula (II) according to the present invention, it is appropriate to use, for example, an optically active aliphatic alcohol as a starting material. Specifically, 3-methylpentanol, 4-methylhexanol, 1-methylheptanol, 2-methylbutanol, 2-methyloctanol,
2-Methylnonanol, 2-methyldecanol and the like are used.

First, the optically active alcohol as described above,
After halogenation or sulfonation, it is reacted with phenylmagnesium halide, and the obtained optically active alkylbenzene is chlorosulfonylated. By reducing the obtained optically active 4-alkylphenylsulfonyl chloride under relatively mild conditions, the compound of the general formula (I
The optically active bis (4-alkylphenyl) disulfide of I) is obtained.

Upon reduction of the above-mentioned optically active 4-alkylphenylsulfonyl chloride, the following general formula (I)

[0024]

[Chemical 6] (R ^* represents an alkyl group having an asymmetric carbon atom and having 4 to 12 carbon atoms.) An optically active 4-alkylbenzenethiol can also be produced as a by-product, but this is removed by, for example, silica gel chromatography or other means. Thus, the optically active bis (4-alkylphenyl) disulfide of the present invention can be obtained.

Further, the optically active bis- (4-alkylphenyl) disulfide of the general formula (II) of the present invention is further reduced to produce the optically active 4-alkylbenzenethiol of the above general formula (I). To do.

The above synthetic routes are summarized as follows.

[0027]

[Chemical 7]

The general formula (I) thus obtained is
The following are mentioned as an example of the compound of (II).

(+)-4- (2'-methylbutyl) benzenethiol (+)-4- (1'-methylpropyl) benzenethiol (-)-4- (1'-methylpropyl) benzenethiol (+) -4- (1'-methylhexyl) benzenethiol (-)-4- (1'-methylhexyl) benzenethiol (+)-4- (1 ', 3'-dimethylpropyl) benzenethiol (-)-4 -(1 ', 3'-Dimethylpropyl) benzenethiol (+)-4- (1'-methylbutyl) benzenethiol (-)-4- (1'-methylbutyl) benzenethiol (+)-4- (3' -Methylpentyl) benzenethiol (-)-4- (2'-methyloctyl) benzenethiol (-)-4- (2'-methylnonyl) benzenethiol (-)-4- ( '- methyldecyl) benzenethiol (+) - 4- (4'-methylhexyl) benzenethiol (+) - bis [4- (2'-methylbutyl) phenyl]
Disulfide (+)-bis [4- (1'-methylpropyl) phenyl] disulfide (-)-bis [4- (1'-methylpropyl) phenyl] disulfide (+)-bis [4- (1'-methyl) Hexyl) phenyl] disulfide (−)-bis [4- (1′-methylhexyl) phenyl] disulfide (+)-bis [4- (1 ′, 3′-dimethylpropyl)
Phenyl] disulfide (−)-bis [4- (1 ′, 3′-dimethylpropyl)
Phenyl] disulfide (+)-bis [4- (1'-methylbutyl) phenyl]
Disulfide (-)-bis [4- (1'-methylbutyl) phenyl]
Disulfide (+)-bis [4- (3'-methylpentyl) phenyl] disulfide (-)-bis [4- (3'-methylpentyl) phenyl] disulfide (-)-bis [4- (2'-methyl) Octyl) phenyl] disulfide (−)-bis [4- (2′-methylnonyl) phenyl]
Disulfide (-)-bis [4- (2'-methyldecyl) phenyl]
Disulfide (+)-bis [4- (4'-methylhexyl) phenyl] disulfide The optically active substance of formula (II) thus obtained is
It is effective to prevent the reverse domain in the TN type cell by adding it to the nematic liquid crystal. In this case, it is preferable to use the liquid crystal composition in an amount of 0.01 to 50% by weight.

When added to the nematic liquid crystal, it can be used as a chiral nematic liquid crystal in a phase transition type liquid crystal element or a white Taylor type guest-host type liquid crystal element as a liquid crystal composition. In this case, it is preferably used in a proportion of 0.01 to 80% by weight of the liquid crystal composition.

The optically active substance of the formula (II) is
The characteristics such as durability can be improved by adding, for example, 0.01 to 80% by weight to a liquid crystal composition exhibiting a ferroelectric chiral smectic liquid crystal state by itself. Further, a liquid crystal composition exhibiting a ferroelectric chiral smectic phase can be provided by adding it to a smectic liquid crystal. In this case, it is preferable to add 0.01 to 80% by weight of the liquid crystal composition.

[0032]

The bis- (4-alkylphenyl) disulfide, which is the optically active substance of the present invention represented by the above formula (II), is added to a nematic liquid crystal to give
It is possible to effectively prevent the reverse domain in the TN type cell.

As described above, the bis- (4-
The alkylphenyl) disulfide can be bonded to a functional material intermediate having an appropriate intermolecular force and shape without impairing the optical activity, and the molecular design can be freely performed. In particular, by selecting the length of the alkyl group, it is possible to control the type of liquid crystal phase and the temperature range that appear in the liquid crystal state.

The liquid crystal composition containing at least one bis- (4-alkylphenyl) disulfide of the present invention can be effectively used for improving the performance by using it as a chiral nematic liquid crystal or a chiral smectic liquid crystal. .

Hereinafter, the present invention will be described more specifically with reference to Examples and Reference Examples.

[0036]

Example 1 Bis [4- (2'-methylbutyl) phenyl] disulfide was prepared by the following first to fourth steps.

First step

[0038]

Embedded image

2-Methylbutyl alcohol (I) 197
g was dissolved in 1370 ml of pyridine, cooled to 10 ° C. or lower in an ice bath, and then p-toluenesulfonyl chloride 5 was added.
12 g was added and stirred for 1 hour. After leaving it in the cold place overnight,
1500 ml of cold water was added and stirred for 2 hours. Next, it was extracted with 200 ml of benzene, washed with 5N HCl and water, dried over anhydrous sodium sulfate, and the solvent was distilled off to obtain 510 g of 2'-methylbutyl (II) 4-methylbenzenesulfonate.

Second step

[0041]

[Chemical 9]

40 g of brombenzene, magnesium 6.
A phenylmagnesium bromide solution prepared from 2 g and 300 ml of ether was cooled to 5 ° C., and 1 ′ of 2′-methylbutyl (II) 4-methylbenzenesulfonate was cooled.
A mixture of 25 g and 130 ml of ether was added dropwise. After stirring for 2 hours, raising the temperature and refluxing for 2 hours,
I left it overnight. 10% H ₂ SO ₄ was added to the reaction solution to adjust the pH to 2. The organic layer was washed successively with an aqueous sodium bicarbonate solution and water, dried over anhydrous magnesium sulfate, and the solvent was evaporated.
The product was subjected to vacuum distillation to obtain 48 g of 4- (2'-
Methylbutyl) benzene (III) was obtained. The IR data is shown below.

IR (cm^-1 ): 2960, 2940, 2
880, 1600, 1500, 1465, 1430, 1
380, 1370.

Third step

[0045]

[Chemical 10]

4- (2'-methylbutyl) benzene (I
II) 49 g was dissolved in 150 ml of chloroform, -1
At 0 ° C., 79 g of ClSO ₃ H was added dropwise for about 1 hour.
Then, the mixture was stirred at room temperature for 6 hours. After the reaction, the mixture was poured into ice and neutralized with a NaOH aqueous solution, and then the solvent was distilled off to obtain 380 g of crystals.

The obtained crystals were dissolved in 350 ml of benzene, and 70 g of PCl ₅ was added little by little at room temperature. Then, the mixture was stirred at 55 ° C. for 5 hours, poured into ice, and the organic layer was washed with water. Further, the organic layer was separated, dried over anhydrous sodium sulfate, and the solvent was distilled off to obtain an oily substance. This oil is
Purified by silica gel column chromatography using n-hexane / isopropyl ether as a mobile phase, 51 g
4- (2 ″ -methylbutyl) benzene-4′-thionyl chloride (IV) was obtained, the IR and NMR data of which are shown below.

IR (cm ^-1 ): 2980, 2940, 2
880, 1600, 1385, 1180.

NMR (ppm): 8.2-7.2 (4
H), 2.7-2.5 (2H), 1.6-0.8 (9
H).

Fourth step

[0051]

[Chemical 11]

410 g of concentrated H ₂ SO ₄ was added to 410 g of water, cooled to -15 ° C., and 46.3 g of 4- (2 ″ -methylbutyl) benzene-4′-thionyl chloride (IV) was added.
Was added dropwise over 20 minutes. Then, zinc powder 108g at 0 ℃
The following was added and stirred at -3 ° C for 2.5 hours. After returning to room temperature, the temperature was slowly raised and the mixture was stirred at 45 ° C. for 70 minutes.

The reaction mixture was extracted with isopropyl ether, washed with water, dried over anhydrous sodium sulfate, and the solvent was distilled off to obtain 25 g of an oily substance. This oily substance was purified by silica gel column chromatography using a mixed liquid of n-hexane / ethyl acetate = 100: 1 as a mobile phase, and bis [4- (2′-methylbutyl) phenyl] disulfide (V) was added to 1 .2g, and (V) and 4- (2 '
17.0 g of a 1: 1 mixture of -methylbutyl) benzenethiol (VI) was obtained. (V) MNR data is shown below.

NMR (ppm): 7.4 to 6.9 (8
H), 2.6 to 2.3 (4H), 1.7 to 0.8 (18)
H).

Reference Example 1 4- (2'-methylbutyl) benzenethiol was produced by a reduction process including the following reactions.

[0056]

[Chemical 12]

68 g of concentrated H ₂ SO ₄ was added to 210 g of ice,
After cooling to -12 ° C, 1.0 g of (V) obtained in Example 1 and 17 g of a mixture of (V) and (VI) were added dropwise over 40 minutes. Then, 53.6 g of zinc powder was added at 0 ° C. or below, and −1
The mixture was stirred at 0 ° C for 2 hours. After returning to room temperature, the temperature was slowly raised and the mixture was stirred at 59 ° C. for 2.5 hours. The optical rotation, IR and NMR data of the product are shown below.

Optical rotation: [α] _D ²⁹ = + 13.2 ° IR (cm ^-1 ): 2970, 2930, 2880, 25
80, 1600, 1500, 1465, 1150, 10
85.

NMR (ppm): 7.2-6.9 (4
H), 3.3 (1H), 2.5 to 2.3 (2H), 1.
7-0.8 (9H). Example 2 To 99 parts by weight of Rixon GR-63 (biphenyl liquid crystal mixture manufactured by Chisso Corporation), 1 part by weight of (+)-bis (4- (2′-methylbutyl) phenyl) disulfide of Example 1 was added. A twisted nematic (TN) cell was prepared using the added liquid crystal mixture. It was observed that this cell had a significantly reduced reverse domain compared to the TN cell made with Rixon GR-63 only.

Claims (2)

(57) [Claims] 1. The following general formula (II): (R ^* represents an alkyl group having 4 to 12 carbon atoms having an asymmetric carbon atom.), Which is an optically active bis (4-alkylphenyl) disulfide. 2. The following general formula (II): (R ^* represents an alkyl group having 4 to 12 carbon atoms having an asymmetric carbon atom), and at least one optically active bis (4-alkylphenyl) disulfide is contained in the liquid crystal composition. .