JPH0665176A - Liquid crystalline compound - Google Patents

Abstract

PURPOSE:To obtain a new compound useful as a guest host type liquid crystal optical element, having excellent compatibility with other liquid crystal compounds. CONSTITUTION:A compound of formula I (X is 1-10C alkyl, cyclohexyl, 1-8C alkoxy, cyano, nitro, etc.; Y is 1-10C alkyl, cyclohexyl;, 1-8C alkoxy, dimethylamino, etc.) such as compound of formula II. The compound of formula I is obtained by diazotizing an aniline derivative of formula III, coupling the resulting substance with a compound of formula IV (A is acyloxy; B is OH or as shown for Y) and hydrolyzing the group A.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel liquid crystal compound. More specifically, it relates to a liquid crystal compound having absorption of visible light, and the compound is used, for example, in a guest-host type liquid crystal optical element.

[0002]

2. Description of the Related Art As a method of providing a colored liquid crystal optical element, a method of dissolving a dichroic dye having different absorption strengths of visible light in the major axis direction and the minor axis direction of the molecule as a guest molecule in a nematic liquid crystal as a host There is. The arrangement of the liquid crystal molecules changes due to the change in the applied electric field, and the arrangement of the dichroic molecules also changes accordingly. Thereby, the visible light absorption of the dye is changed by applying an electric field, and a colored liquid crystal optical element is manufactured. The dichroic dye, which is indispensable for the guest-host type liquid crystal optical element, generally has a rod-like shape, and the visible light absorption wavelength range is determined by the conjugated electron system serving as the nucleus.

Since the azobenzene dye is rod-shaped in itself, it is useful as a dichroic dye that gives a yellow to red color tone, and some dyes are already known (Japan Society for the Promotion of Science, 142th Committee). See "Liquid Crystal Device Handbook", edited by Nikkan Kogyo Shimbun (1989), page 728). The coloring density of the liquid crystal containing these dichroic dyes is determined by the molecular extinction coefficient of the dye and the density in the liquid crystal. Therefore, one of the properties required for the dichroic dye is excellent compatibility with the liquid crystal, but the low-viscosity liquid crystal used to enhance the response speed has a low polarity, so The solubility is not good, and there is a problem that it is generally difficult to obtain a sufficient coloring density. Moreover, many of the azobenzene derivatives also have a drawback that they are likely to undergo a photogeometric isomerization reaction by the action of light.

[0004]

The present invention has excellent compatibility with liquid crystals, does not cause a photogeometric isomerization reaction by the action of light, and has absorption of visible light suitable for guest-host type liquid crystal optical elements. It is intended to provide a liquid crystal compound.

[0005]

The present inventors have completed the present invention as a result of intensive studies to achieve the above object. That is, the present invention

Equation (1) Equation (1)

[Chemical 2]

(In the formula (1), X is a carbon number of 1-10.
Represents an alkyl group, a cyclohexyl group, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 6 carbon atoms, a cyano group or a nitro group, and Y is an alkyl group having 1 to 10 carbon atoms, a cyclohexyl group, or a carbon number. 1-8 alkoxy group, 1-6 alkoxycarbonyl group, dimethylamino group or diethylamino group), and a hydroxyl group at the ortho position. The liquid crystal compound represented by the formula (1) is characterized by having a hydroxy group at the ortho position of the azo group, and has nematic, smectic or cholesteric liquid crystallinity.

To obtain the azo compound derivative of the present invention represented by the formula (1), the formula (2)

[0009]

[Chemical 3] (In the formula (2), X has the same meaning as described above) The aniline derivative compound is diazotized by a known method to obtain the formula (3)

[0010]

[Chemical 4]

(In the formula (3), A represents an acyloxy group, B is a hydroxyl group or has the same meaning as the above-mentioned Y group), or B is a hydroxyl group. If present, this hydroxyl group is further alkylated or acylated by a known method. The compound of formula (1) can be obtained by hydrolyzing A, which is an acyloxy group, in the azo compound derivative thus obtained. As the substituents X and Y of the compound of the formula (1), methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, cyclohexyl group, methoxy group, Ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl Group, hexyloxycarbonyl group, cyano group, nitro group, dimethylamino group, diethylamino group.

The compound represented by the formula (1) thus obtained exhibits liquid crystallinity and has a yellow to reddish tinge. The hydroxyl group at the ortho position easily forms a hydrogen bond with one nitrogen atom of the azo group, and thus significantly stabilizes the planarity advantageous for the liquid crystal skeleton. In addition, even if the visible light is irradiated, the trans-cis photoisomerization reaction that an ordinary azobenzene derivative exhibits does not occur, and the color tone is stable even in a bright place. It is considered that this is because the hydrogen atom of the ortho-position hydroxyl group is transferred to the nitrogen atom of the azo group by photoexcitation and then immediately returns to the original structure. The compound represented by the formula (1) exhibits good compatibility with other liquid crystal compounds. The liquid crystal compound used here includes those exhibiting a nematic, cholesteric or smectic phase, and examples thereof include, for example, “Liquid Crystal Device Handbook” edited by Japan Society for the Promotion of Science, 142 Committee, Nikkan Kogyo Shimbun (1989 , But not limited thereto.

[0013]

EXAMPLES The present invention will be described in more detail with reference to the examples below, including the synthetic method, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 Synthesis of a compound represented by the following formula (4):

[0015]

[Chemical 5]

Hexylaniline (17.7 parts) was added dropwise to 33.2 parts of concentrated hydrochloric acid and 48 parts of ice water to disperse. After adding an ice bath, keep sodium nitrite 7.2 while keeping the temperature below 10 ° C.
What was dissolved in 20 ml of water was added dropwise. Stir for 30 minutes at 10 ° C. or lower to diazotize. The solution containing the diazonium salt becomes transparent and uniform. The reaction solution is made neutral with a sodium carbonate solution. Separately, 21.4 parts of resorcinol monobenzoate dissolved in 200 ml of methanol is added dropwise to the diazonium solution while maintaining the temperature at 10 ° C. or lower. A saturated aqueous sodium acetate solution is added, and the mixture is stirred at 10 ° C. or lower for 30 minutes and at room temperature for 2 hours while keeping the mixture neutral. The precipitate formed was filtered off, washed with water and n-hexane,
By drying, 35.6 parts of the compound of the following formula (5) was obtained.

[0017]

[Chemical 6]

Next, 5 parts of the compound of the formula (5) was dissolved in 30 parts of DMF-acetone mixed solvent, 2.4 parts of n-hexyl bromide and 2.7 parts of potassium carbonate were added and the mixture was refluxed at 2
React on time. n-Hexane and water are added, and the aqueous layer is extracted with n-hexane. The organic layer is dried over sodium sulfate,
The solvent is distilled off. The obtained solid is dissolved in methanol, 1.0 part of potassium hydroxide is added, and the mixture is stirred at 25-30 ° C for 3 hours. After that, add 0.5 part of potassium hydroxide and add 5
The mixture was stirred at 0 ° C for 1 hour. Add hydrochloric acid to acidify the hydrochloric acid and n-
Extract with hexane-acetic acid ethyl ester. The solvent is distilled off to obtain a solid, which is recrystallized from a solvent of n-hexane to obtain 2.4 parts of the compound of the formula (4). The obtained compound was confirmed to have the structure of Formula (4) by instrumental analysis such as mass spectrum, infrared absorption spectrum, nuclear magnetic resonance spectrum, and elemental analysis.

UV (ethanol) λ _max (nm): 365 IR (KBr) ν _max (cm ⁻¹ ): 3440, 1625 H-NMR, δ _{H (ppm)} (CDCl ₃ ): 0.89 (3 H, t), 0.
91 (3H, t), 1.2-1.7 (14H, mb), 1.8 (2H, m), 2.68 (2H, m)
t), 4.05 (2H, t), 6.46 (1H, d), 6.60 (1H, d), 7.26 (1H,
s), 7.30 (2H, d) 7.72 (1H, d), 7.76 (1H, d) MS (m / e) = 382 (MW = 382) Elemental analysis value (calculation) C ₂₄ H ₃₄ N ₂ O ₂ C = 75.39, H = 8.90, N = 7.33 (actual measurement) C = 76.32, H = 8.87, N = 7.32 Further, the phase transition temperature of this compound is C-N point. 36 ° C, N-
The point I was 76 ° C.

Example 2-7 Compounds (7)-(9) were obtained in the same manner as in Example 1 except that n-propylpromide, pentyl bromide and n-octyl bromide were used instead of n-hexylpromide. Synthesized. Compounds (10) to (12) were synthesized by the same procedure as in Example 1 except that ethyl aniline, decyl aniline and cyclohexyl aniline were used instead of hexyl aniline. The structure of the obtained compound was confirmed by instrumental analysis. Moreover, all the compounds showed liquid crystallinity. Table 1 shows the structure of the compound and its absorption maximum wavelength.

[0021]

[Chemical 7]

[0022]

Table 1 Example compounds In the structural formula (6), λ _max No. No. _{R 1 R 2 (nm) 2} (7) -n-C 6 H 13 -n-C 3 H 7 364 3 (8) -n-C 6 H 13 -n-C 5 H 11 365 4 (9) - _{n-C 6 H 13 -n-} C 8 H 17 365 5 (10) -C 2 H 5 -n-C 6 H 13 364 6 (11) -n-C 10 H 21 -n-C 6 H 13 365 _{7 (12) -C 6 H 11} -n-C 6 H 13 366

Example 8 Synthesis of compound represented by the following formula (13):

[0024]

[Chemical 8]

13.2 parts of para-cyanoaniline was added dropwise to 33.2 parts of concentrated hydrochloric acid and 48 parts of ice water to disperse. After adding an ice bath, keep the temperature below 10 ° C and sodium nitrite 7.
What dissolved 2 parts in 20 ml of water is dripped. Stir for 30 minutes at 10 ° C. or lower to diazotize. The solution containing the diazonium salt becomes transparent and uniform. The reaction solution is made neutral with a sodium carbonate solution. Separately, 21.4 parts of resorcinol monobenzoate dissolved in 200 ml of methanol is added dropwise to the above diazonium solution while maintaining the temperature at 10 ° C. or lower. A saturated aqueous sodium acetate solution is added, and the mixture is stirred at 10 ° C. or lower for 30 minutes and at room temperature for 2 hours while keeping the mixture neutral. The precipitate formed was filtered off, washed with water and n-hexane,
By drying, 28.6 parts of the compound of formula (14) was obtained.

[0026]

[Chemical 9]

Next, 4.5 parts of the compound of formula (14) was added to DMF.
-Dissolve in 30 parts of acetone mixed solvent, add 2.4 parts of n-hexyl bromide and 2.7 parts of potassium carbonate, and react at reflux temperature for 2 hours. n-Hexane and water are added, and the aqueous layer is extracted with n-hexane. The organic layer is dried over sodium sulfate and the solvent is distilled off. The obtained solid is dissolved in methanol, 1.0 part of potassium hydroxide is added, and the mixture is added at 25-30 ° C.
Stir for 3 hours. Then, 0.5 part of potassium hydroxide was added, and the mixture was stirred at 50 ° C. for 1 hour. Water is added to acidify the hydrochloric acid, and the mixture is extracted with n-hexane-acetic acid ethyl ester.
The solvent is distilled off to obtain a solid, which is recrystallized from an n-hexane solvent to obtain 2.2 parts of the compound of the formula (13). The obtained compound was confirmed to have the structure of Formula (13) by instrumental analysis such as mass spectrum, infrared absorption spectrum, nuclear magnetic resonance spectrum, and elemental analysis.

UV (ethanol) λ _max (nm): 392 IR (KBr) ν _max (cm ⁻¹ ): 3440, 222
0,1620 H-NMR, δ _{H (ppm)} (CDCl ₃ ): 0.90 (3 H, t), 1.
2-1.7 (6H, m), 1.80 (2H, m), 4.05 (2H, t), 6.46 (1H, d) 6.60 (1H, dd), 7.26 (1H, s), 7.6-7.9 (4H, m ) MS (m / e) = 323 (MW = 323) Elemental analysis value (calculation) C ₁₉ H ₂₁ N ₃ O ₂ C = 70.59, H = 6.50, N = 13.00 (actual measurement) C = 71.02, H = 6.44, N = 13.30 Further, the phase transition temperature of this compound was 90 ° C. at C-N point, N-
The point I was 95 ° C.

Examples 9-13 In Example 8, para-nitroaniline was used in place of para-cyanoaniline, p-aminobenzoic acid butyl ester,
Compounds (16)-(18) were synthesized by the same procedure using p-aminobenzoic acid ethyl ester. Compounds (19) and (20) were synthesized in the same manner as in Example 8 except that cyclohexyl bromide and n-propyl bromide were used instead of hexyl bromide.
The structure of the obtained compound was confirmed by instrumental analysis. Moreover, all the compounds showed liquid crystallinity. Table 2 shows the structures of the compounds and their absorption maximum wavelengths.

[0030]

[Chemical 10]

[0031]

Table 2 Example compounds In the structural formula (15), λ _max No. No. _{R 3 R 4 (nm) 9} (16) -NO 2 -n-C 6 H 13 412 10 (17) -COOC 4 H 9 -n-C 6 H 13 386 11 (18) -COOC 2 H 5 -n _{-C 6 H 13 384 12 (19} ) -CN -C 6 H 11 393 13 (20) -CN -n-C 3 H 7 392

Example 14 Synthesis of compound represented by the following formula (21):

[0033]

[Chemical 11]

Hexylaniline (17.7 parts) was dropped into concentrated hydrochloric acid (33.2 parts) and ice water (48 parts) to carry out partial oxidation. After adding an ice bath, keep sodium nitrite 7.2 while keeping the temperature below 10 ° C.
What was dissolved in 20 ml of water was added dropwise. Stir for 30 minutes at 10 ° C. or lower to diazotize. The solution containing the diazonium salt becomes transparent and uniform. The reaction solution is made neutral with a sodium carbonate solution. Separately, 22.8 parts of m-methoxyphenol monobenzoate dissolved in 200 ml of methanol is added dropwise to the above diazonium solution while maintaining the temperature at 10 ° C or lower. A saturated aqueous sodium acetate solution is added, and the mixture is stirred at 10 ° C. or lower for 30 minutes and at room temperature for 2 hours while keeping the mixture neutral. The formed precipitate was filtered off, washed with water and n-hexane, and dried to obtain 32.5 parts of the compound of formula (22).

[0035]

[Chemical 12]

Next, 4.2 parts of the compound of the formula (22) was dissolved in methanol, 1.0 part of potassium hydroxide was added, and
Stir at −30 ° C. for 3 hours. After that, potassium hydroxide 0.5
Parts were added and the mixture was stirred at 50 ° C. for 1 hour. Water is added to acidify the hydrochloric acid, and the mixture is extracted with n-hexane-acetic acid ethyl ester. The solvent is distilled off to obtain a solid, which is recrystallized from an n-hexane solvent to obtain 2.8 parts of the compound of the formula (21). The obtained compound was confirmed to have the structure of Formula (21) by instrumental analysis such as mass spectrum, infrared absorption spectrum, nuclear magnetic resonance spectrum, and elemental analysis.

UV (ethanol) λ _max (nm): 360 IR (KBr) ν _max (cm ⁻¹ ): 3440, 1625 H-NMR, δ _{H (ppm)} (CDCl ₃ ): 0.90 (3 H, t), 1.
2-1.8 (8H, m), 2.68 (2H, t), 3.90 (3H, s), 6.46 (1H, d),
6.60 (1H, dd), 7.26 (1H, s), 7.30 (2H, d), 7.72 (1H, d),
7.76 (1H, d) MS (m / e) = 382 (MW = 382) Elemental analysis value (calculation) C ₁₉ H ₂₄ N ₂ O ₂ C = 73.08, H = 7.69, N = 8.97 (Measurement) C = 73.40, H = 7.34, N = 9.20 Further, the phase transition temperature of this compound was 77 ° C. at C-N point, N-
The point I was 80 ° C.

Examples 15 to 17 In the same manner as in Example 14 except that m-diethylaminophenol monobenzoate and m-dimethylaminophenol monobenzoate were used instead of m-methoxyphenol monobenzoate, the compound (23) was obtained. ,
(24) was obtained. Also, in Example 16, p-methoxyaniline was used in place of hexylaniline, and the same operation was performed to obtain compound (25). The structure of the obtained compound was confirmed by instrumental analysis. Moreover, all the compounds showed liquid crystallinity. Table 3 shows the structures of the compounds and their absorption maximum wavelengths.

[0039]

[Chemical 13]

[0040]

Table 3 Example compounds In the structural formula (26), λ _max No. No. _{R 5 R 6 (nm) 15} (23) -n-C 6 H 13 -N (C 2 H 5) 2 416 16 (24) -n-C 6 H 13 -N- (CH 3) 2 414 17 ( 25) —OCH ₃ —OCH ₃ 356

[0041]

The liquid crystal compound represented by the general formula (1) of the present invention is colored and exhibits excellent compatibility with other liquid crystal compounds, and therefore it is soluble in itself or in other liquid crystal compounds. In such a state, it is suitably used for a guest / host type liquid crystal optical element.

Claims (1)

[Claims] 1. Formula (1): (In the formula (1), X is an alkyl group having 1 to 10 carbon atoms, a cyclohexyl group, an alkoxy group having 1 to 8 carbon atoms,
Represents an alkoxycarbonyl group having 1 to 6 carbon atoms, a cyano group or a nitro group, Y represents an alkyl group having 1 to 10 carbon atoms,
A liquid crystal compound represented by a cyclohexyl group, an alkoxy group having 1 to 8 carbon atoms, a dimethylamino group or a diethylamino group).