JPS6045872B2 - liquid crystal compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel liquid crystalline compound useful as an electro-optical display element material, and more particularly to a cyanodihydrophenanthrene derivative.

Since nematic liquid crystals tend to cause light scattering and birefringence under the influence of an electric field, that is, their electro-optical properties change significantly, they have come to be widely used in display devices.

The properties that the nematic liquid crystal used in display devices should have include chemical stability, particularly against moisture, air, light in the visible region and ultraviolet region, and furthermore, direct current or alternating current electric fields. In addition, when it is incorporated into an electro-optical display device and commercialized, it is required that the nematic liquid crystal temperature range is at least 00 to 600C.
It is also important that the material does not exhibit a specific absorption band in the visible region, that is, it is colorless. As a result of intensive research to develop a liquid crystalline compound that satisfies these requirements, the present invention has been completed by discovering the suitability of a compound represented by the following general formula (1). .

General formula NC OR (1) (In the formula, R is a linear alkyl group having 1 to 8 carbon atoms, a linear alkylcarbonyl group having 1 to 8 carbon atoms, and 1 to 8 carbon atoms at the 4th position. benzoyl group having a linear alkyl group having 1 to 8 carbon atoms in the 4th position, or cyclohexylyl having a linear alkyl group having 1 to 8 carbon atoms in the 4th position represents a group.

) Since the compound represented by the above general formula (1) has a nitrile group at the 7-position, it exhibits strong positive dielectric anisotropy,
It is particularly promising as a constituent of liquid crystal compositions used in twisted nematic (TN) liquid crystal devices.
*The liquid crystal compound of the present invention can be represented by the general formula (1), and can be synthesized via the following route when 9,10-dihydrophenatonlene (4) is used as a starting material. In order to use the liquid crystalline compound obtained through such a synthesis process in an electro-optical display device, it may be used alone or in combination of two or more compounds represented by the general formula (1). , or may be used in combination with other liquid crystalline compounds exhibiting nematic liquid crystals.

Such mixable nematic liquid crystals have the general formula (wherein R1 and R2 each independently represent an alkyl group or an alkoxy group having 1 to 10 carbon atoms).

), general formula (wherein R3 and R4 each independently represent an alkyl group or an alkoxy group having 1 to 10 carbon atoms.

), general formula (in the formula, R5 and R6 each independently represent an alkyl group or an alkoxy group having 1 to 10 carbon atoms).

), general formula (in the formula, R7 and R8 each independently represent an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, or an alkylcarbonyloxy group having 1 to 10 carbon atoms).

), representing a general formula group.

), general formula (In the formula Rll and Rl.

each independently represents an alkyl group, an alkoxy group, an alkylcarbonyl group or an alkylcarbonyloxy group having 1 to 10 carbon atoms. ), general formula (wherein Rl3 and Rl4 each independently represent an alkyl group, an alkoxy group, or an alkylcarbonyl group having 1 to 10 carbon atoms.

), general formula (wherein Rl5 represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms.

), general formula (wherein Rl6 represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms.

), general formula (wherein Rl7 represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group).

), general formula (wherein Rl8 represents an alkyl group, an alkoxy group, or an alkylcarbonyloxy group having 1 to 10 carbon atoms.

), general formula (wherein Rl9 represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms.

), General Formula 7 (In the formula, R2O represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms.

), or the general formula (in the formula, R2l represents an alkyl group having 1 to 8 carbon atoms).

) etc.

By mixing these, the nematic liquid crystal temperature range can be lowered, and a more practical liquid crystal composition can be obtained. If an electro-optical display element is filled with nematic liquid crystal and a voltage is applied, it can be used as a display, but in addition to nematic liquid crystal, generally known alignment agents,
There is no problem in adding viscosity reducing agents, dichroic dyes, and other additives. The liquid crystal compound according to the present invention has the general formula (1
), and since there is a nitrile group at the 7-position, it has strong positive dielectric anisotropy.

Furthermore, it is highly stable against moisture, air, and light, and exhibits a milky white color with no coloration in the liquid crystal state. Furthermore, the nematic liquid crystal has a characteristic that the temperature range is much wider than that of other nematic liquid crystals.
On the other hand, even a compound that does not exhibit a nematic liquid crystal phase is suitable for mixing with a compound represented by the general formula (1) that exhibits a nematic liquid crystal phase because its properties will not be impaired. Next, the present invention will be specifically explained using synthesis examples.

Synthesis of compound (B) (Step 1) 20.5 g of 9,10-dihydrophenanthrene was dissolved in 1 acetic acid.
Dissolve in 20mt and keep at 30℃ while stirring thoroughly,
Nitration was carried out by dropping 30 ml of fuming nitric acid over 2 hours.

The reaction solution was poured into 3e of water, and the precipitated crystals were separated. The obtained crystals were recrystallized from ethyl alcohol until the melting point was 8.
2-nitro-9,10-dihydrophenanthrene (B) having a temperature of 0 to 81°C was obtained. The yield was 55%. Compound(
Synthesis of C) (Step 2) Add 54 g of iron to a mixture of 2.2 ml of concentrated hydrochloric acid and 27 mL of water, and add 28 g of the compound (B) obtained in Step 1 to this on a hot water bath for 2 hours while stirring. and added.

After the addition, stirring was continued for another 4 hours, and the reaction solution was made basic by adding a 20% aqueous sodium carbonate solution, filtered while hot, and the separated solid was washed with hot ethanol. The washing solution and the washing solution were combined and subsequently cooled to obtain 2-amino-9,10-dihydrophenanthrene (C) having a melting point of 38 to 41°C. The yield was 85%. Synthesis of Compound (2) (Step 3) 20.4 g of Compound (C) obtained in Step 2 was dissolved in 65Tn1 of acetic acid, and 20 ml of acetic anhydride was added.

After the addition, the mixture was heated to 80°C and stirred for 30 minutes to effect acetylation. After cooling, the precipitated crystals were recrystallized with methanol to obtain 2-N-acetylamino-9,10-dihydrophenanthrene (2) having a melting point of 173.5 to 174.0°C. Synthesis of compound (E) (Step 4) 16.6 g of compound (9) obtained in Step 3 and 10.5 g of acetyl chloride
28 g of aluminum chloride was dissolved in 200 ml of nitrobenzene and stirred at room temperature.
00ml solution was slowly added.

Subsequently, after stirring overnight, the resulting crystals were poured into 300 mL of ice water and recrystallized from methanol to obtain 2-N-acetylamino-7-acetyl-9,10-dihydrophenanthrene (E) with a melting point of 214-215°C. . Synthesis of Compound (F) (Step 5) Compound (E) obtained in Step 4 17.
A mixture of 7 g of iodine and 16.5 g of iodine and 60 ml of pyridine was reacted at 100° C. for 2 hours.

After cooling, the brown solid was washed with water, dilute hydrochloric acid, and water to obtain pyridinium, which is compound (F). Synthesis of Compound (G) (Step 6) Compound (F) obtained in Step 5 was
% potassium hydroxide aqueous solution and refluxed for 5 hours, the mixture was cooled and acidified with hydrochloric acid to precipitate crystals.

The obtained crystals were recrystallized with methyl alcohol, and the melting point was 2.
2-amino-7-carboxy9,1 at 39-240°C
0-dihydrophenanthrene (G) was obtained. Compound (H
) Synthesis (Step 7) 8.8 g of compound (G) obtained in Step 6 was added with 130 ml of acetic acid.
Add 20 ml of t1 water and stir to raise the temperature to 80°C.

Dilute sulfuric acid consisting of 4 ml of concentrated sulfuric acid and 130 mt of water is added to this to form a sulfate, and the mixture is cooled to 0°C. Next, a solution prepared by dissolving 3 g of sodium nitrite in 150 mL of water was gradually added dropwise to this solution to effect a diazotization reaction. Excess sodium nitrite was destroyed by adding urea. 22ml of concentrated sulfuric acid,
A solution consisting of 60 ml of water is brought to a boil, and the above diazotization reaction solution is gradually added thereto. After the addition is complete, the solution is refluxed, and then diluted to twice the volume with water to form white crystals (H). I also got it. This was recrystallized from a mixed solvent of ethanol and water.
The melting point was 248-250°C. Synthesis of compound (1) (Step 8) Compound (H) obtained in Step 7 6.8 g 1 Acetic anhydride 40
A solution consisting of 200 ml of mt1 acetic acid was maintained at 60°C, and a mixed solution of 1 ml of sulfuric acid and 6 ml of acetic acid was added thereto while stirring, and the temperature was raised to 90°C.

The mixture was then diluted with a large amount of water, and the precipitated crystals were washed with water to obtain compound (1) having a melting point of 238-239°C. Compound (J
) Synthesis (Step 9) 5.5 g of compound (1) obtained in Step 8, 4.4 g of thionyl chloride, 80 ml of benzene, 8 ml of dimethylformamide
After refluxing the solution consisting of m1 at 80° C. for 2 hours, thionyl chloride and benzene were distilled off under reduced pressure.

The remaining chlorinated crystals were dissolved in anhydrous acetone, and ammonia gas was introduced to obtain crystals of compound (J). Subsequently, after washing with water, it was recrystallized from ethyl acetate. Melting point is 20
The temperature was 3-204°C. Synthesis of compound (K) (Step 10) Add 150 m of acetic anhydride to 4 g of compound (J) obtained in step 9.
1 was added and the mixture was refluxed for 4.5 A with stirring, and then acetic anhydride and the acetic acid produced were distilled off under reduced pressure.

A dehydration reaction occurs from compound (J), leaving compound (K). Synthesis of Compound (L) (Step 11) The crude product of Compound (K) obtained in Step 10 is dissolved in 150 ml of methanol and boiled.

150 ml of 10% aqueous sodium hydroxide solution was gradually added to the mixture, and the mixture was stirred for 10 hours for hydrolysis. This reaction solution was poured into 1e of ice water and made acidic by adding dilute hydrochloric acid, and the precipitated crystals were washed with water and then recrystallized with ethyl acetate to obtain compound (L) with a melting point of 162.0-163.0°C. Ta.
The intermediates obtained in Steps 1 to 9 and Step 11 were confirmed by infrared absorption spectrum (IR) and nuclear magnetic resonance spectrum (NMR) and used in the next step. FIG. 1 shows an NMR chart of compound (L). Synthesis of the compound represented by general formula (1) (Step 1
2) (a) 2-n-hexyloxy 7-cyano 9,1
2.2 g of compound (L) obtained through the synthesis step 11 of 0-dihydrophenanthrene (A). 01 mol) was dissolved in 50 ml of acetone, and 5 g of potassium carbonate was added.

While refluxing this mixture, add 2.5 g of n-hexyl bromide.
After the mixture was gradually added dropwise to g, refluxing was continued for 5 hours. After cooling, the potassium carbonate was poured out from door to door, the Oki liquid was concentrated, and the precipitated crystals were recrystallized from a mixed solvent of benzene and n-hexane. Differential thermal analysis of this product revealed that the melting point was 87.5°C.
The NMR chart of the compound obtained in this synthesis example is shown in FIG. (2.2 g (I).01 mol of compound (L) obtained through synthesis step 11 of 2-methoxy7-cyano-9,10-dihydrophenanthrene) was dissolved in 50 mL of acetone, and 5 g of potassium carbonate was added.

While refluxing the mixture, 2.5 g of dimethyl sulfate was gradually added dropwise, and the mixture was refluxed for 1 hour. After cooling, the potassium carbonate was separated, the liquor was concentrated, and the precipitated crystals were mixed with benzene and n.
- Recrystallized from a mixed solvent of hexane. This compound has 10
6. It changes from a solid phase to an isotropic liquid crystal phase at ℃, then when it is allowed to cool, it changes from an isotropic liquid phase to a nematic liquid crystal phase at 47.0 ℃, and when it is allowed to cool further, it changes from a nematic liquid crystal phase at 36.0 ℃. It became a solid phase.

An NMR chart of the compound obtained in this synthesis example is shown in FIG. (b) Synthetic compound of 2-n-heptanoyloxy-7-cyano-9,10-dihydrophenanthrene (
L) 2.2g (a). 01 mol) was dissolved in 50 mL of benzene, 2 ml of pyridine was added, and the mixture was heated to 50°C.

1.5 g of n-heptanoyl chloride was gradually added to this, and the mixture was stirred at 60°C for 5 hours. After cooling, the generated pyridine hydrochloride was separated, and the liquid solution was washed with water, dehydrated, concentrated, and recrystallized with a mixed solvent of benzene and n-hexane. The transition temperature of this material was 48.0°C, from a solid phase to an isotropic liquid phase, and when it was then left to cool, it changed from an isotropic liquid phase to a nematic liquid crystal phase at 42.0°C. Even when the temperature was further lowered to 20°C, the nematic liquid crystal phase remained and the solid phase did not reach the level. An NMR chart of the compound obtained in this synthesis example is shown in FIG.

(C) Synthesis of 2-(4″-n-butylcyclohexylyloxy)-7-cyano-9,10-dihydrophenanthrene 4-n-butylcyclohexanecarboxylic acid 36.8
g(a). 2 moles) was dissolved in 50 g of thionyl chloride, and 1
After refluxing for a period of time to effect chlorination, excess thionyl chloride was distilled off to obtain 4-n-butylcyclohexyl chloride.

Next, in this, the compound (L) obtained through step 11
44.2g (a). A solution prepared by dissolving 2 mol) in 500 mt of benzene was added and stirred, and 20 g of pyridine was added dropwise. Next, this mixed solution was reacted at a temperature of 50 to 60° C. for 2 hours to effect esterification. After washing the reaction solution with dilute hydrochloric acid and water, the benzene was distilled off, and the residue was recrystallized from n-hexane to obtain 2-(4″-n-butylcyclohexyloxy)-7-cyano-9,10-dihydrophenanthrene. The yield was 80%.Differential thermal analysis of this product showed that at 90°C, the solid state changed to a nematic liquid crystal phase.
It transitioned to an isotropic liquid phase at 25°C. Next, when this product was allowed to cool, it turned into a nematic liquid crystal again at 225°C and a solid phase at 18°C. Further, elemental analysis 1R and NMR spectrum were taken, and it was confirmed that it was 2-(4''-n-butylcyclohexyloxy)-7-cyano-9,10-dihydrophenanthrene.

Elemental analysis Calculated value as C26H29NO2 C: 80.6% H: 7.5% N: 3.6% Analysis value C: 80.5% H: 7.4% N: 3.6% IR spectrum Attached drawing No. See Figure 4. NMR spectrum. See attached drawing, Figure 5. (d) 2-(4'-n-butoxybenzoyloxy)-
Synthesis of 7-cyano-9,10-dihydrophenanthrene 4-n-butoxybenzoic acid 19.4 g (a). 1 mole)
was dissolved in 25 g of thionyl chloride, refluxed for 1 hour to perform a chlorination reaction, and then excess thionyl chloride was distilled off to obtain 4-butoxybenzoic acid chloride.

Next, in this, the compound (L) obtained through step 11
22.1g (a). A solution prepared by dissolving 1 mole of 1 mole) in 500 ml of benzene was added and stirred, and 20 g of pyridine was added dropwise. Next, this mixed solution was reacted at a temperature of 50 to 60° C. for 2 hours to effect esterification. After washing the reaction solution with dilute hydrochloric acid and water, the benzene was distilled off, and the residue was recrystallized from n-hexane to give 2-(4″-n-butoxybenzoyloxy).
-7-cyano9,10-dihydrophenanthrene 29
I got g. The yield was 75%. Differential thermal analysis of this material revealed that it transitioned from a solid phase to a nematic liquid crystal phase at 118.0°C and to an isotropic liquid phase at 249.0°C. Next, when this material was allowed to cool, it transformed to a nematic liquid crystal phase at 240° C., and did not become a solid phase even when the temperature was lowered to room temperature (20° C.), but maintained the liquid crystal phase. Elemental analysis, IR and NMR spectra were also carried out and it was confirmed that it was 2-(4''-n-butoxybenzoyloxy)-7-cyano-9,10-dihydrophenanthrene.Elemental analysis C26H23NO3
Calculated value C: 78.5% H: 5.8% N: 3.5% Analysis value C: 78.6% H: 5.8% N: 3.5% NMR spectrum See attached drawing Figure 6 (2) 2-(4″-n-butylbenzoyloxy)-7
-2.2 g (4) of compound (L) obtained through synthesis step 11 of cyano-9,10-dihydrophenanthrene
．． 01 mol) in 50 ml of benzene, 2 mol of pyridine
mt was added.

This mixture was heated to 50° C., and 2.0 g (0.01 mo) of n-butylbenzoyl chloride was gradually added. After the addition, the mixture was stirred at 60° C. for 5 hours, treated in the same manner as in Synthesis Example (b), and recrystallized from a mixed solvent of benzene and n-hexane. This material transitioned from a solid phase to a nematic liquid crystal phase at 125°C, and from a nematic liquid crystal phase to an isotropic liquid crystal phase at 216°C. Next, when this was allowed to cool, it turned into a nematic liquid crystal phase again at 216°C and turned into a solid phase at 40°C. Compound (f
) ~ (p) melting point (Mp), transition point from solid phase to nematic liquid crystal phase (CH), transition point from nematic liquid crystal phase to isotropic liquid phase (NI), and transition point from nematic liquid crystal phase to solid phase The transition point (NC) is shown in the following table.

All numbers indicate Celsius temperature. The numbers in parentheses indicate the temperature when the temperature drops using a monotropic liquid crystal.

[Brief explanation of drawings]

Figure 1 shows compound (L), Figure 2 shows 2-n-hexyloxy7-cyano 9,10-dihydrophenanthrene, Figure 3 shows 2-n-heptanoyloxy-7-cyano 9,
4 and 5 are NMR spectra of 10-dihydrophenanthrene, respectively.
butylcyclohexyl and lyloxy)-7-cyano 9,
IR and N of 10-dihydrophenanthrene, respectively
It is an MR spectrum diagram.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, R is a linear alkyl group having 1 to 8 carbon atoms;
~8 linear alkylcarbonyl group, a benzoyl group having a linear alkyl group having 1 to 8 carbon atoms at the 4th position, a benzoyl group having a linear alkoxy group having 1 to 8 carbon atoms at the 4th position, or a cyclohexylyl group having a linear alkyl group having 1 to 8 carbon atoms at the 4-position.