JPH021830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel organic compound, and more particularly to a novel liquid crystal compound having positive dielectric anisotropy.

As is well known, liquid crystal materials with positive dielectric anisotropy can be used in liquid crystal display devices that use nematic liquid crystals with twisted alignment, so-called TN type cells, and can also be used as host cells by adding appropriate dye materials. It is also used in color liquid crystal display elements that apply this effect. Currently, there is no single compound of these liquid crystal materials that can withstand practical use due to its various properties, such as liquid crystal temperature range, operating voltage, and response performance. Currently, liquid crystal compounds are mixed to obtain products that can withstand a certain level of use.

An object of the present invention is to provide a liquid crystal compound that has excellent practical performance and is useful as a component of a stable liquid crystal composition, which has positive dielectric anisotropy, The present invention also provides a novel liquid crystal compound that has a wide liquid crystal temperature range, a high clearing point (NI point), and excellent stability.

That is, the present invention is based on the general formula 4-(trans-4'-alkyloxycyclohexyl)benzoic acid 3''-chloro-
4″-cyanophenyl ester.

Although the compound of the present invention has a wide nematic temperature range, it has a high melting point (C-N point), so the practical use of this compound alone as a liquid crystal material for display devices is limited. However, because it has excellent compatibility with other liquid crystal compounds and has a high clearing point (N-I point), other liquid crystal substances such as Schiff's base, azoxy, benzoic acid phenyl ester, and cyclohexanecarboxylic acid phenyl Ester type, cyclohexane carboxylic acid cyclohexane ester type, biphenyl type,
It is useful as a so-called high-temperature liquid crystal component that increases the clearing point by mixing with one type of liquid crystal such as phenylcyclohexane type, phenylpyridine type, phenylmetadioxane type, or a mixture of several types of liquid crystals, Furthermore, cyanoterphenyls, which have been widely used for similar purposes,
Compared to liquid crystal materials such as cyanobiphenylcyclohexane, this compound has a large dielectric anisotropy, that is, Δε (estimated value by extrapolation is about 43.9), and has the characteristic of lowering the driving voltage of liquid crystal compositions containing this compound.

The compound of formula () can be produced by the following steps.

First, the known substance methyl trans-4-cyclohexanecarboxylate (W, S, Johnson et al.
JACS 67 , 1045 (1945)) () is reduced with a reducing agent such as lithium aluminum hydride (LiAlH ₄ ) to obtain trans-4-phenylcyclohexylmethanol (). () in dry pyridine
-React with toluenesulfonyl chloride to obtain trans-4-phenylcyclohexylmethyl p-toluenesulfonic acid (). By reacting this () with an alcoholate, trans-4-alkyloxymetal-1-phenylcyclohexane () is obtained. Compound () is heated with iodine and iodic acid in a solvent to form 4-(trans-4'-alkyloxymethylcyclohexyl)-iodobenzene (), and () is reacted with a cyanating agent such as cuprous cyanide. and 4-(trans-4'-alkyloxymethylcyclohexyl)-benzonitrile () are obtained. compound () in a solvent
When heated with KOH etc., it hydrolyzes to form 4-(trans-4'-alkyloxymethylcyclohexyl)
It becomes benzoic acid (). () is reacted with thionyl chloride to produce benzoic acid chloride, and then 3
-When reacting with chloro-4-cyanophenol in pyridine, the target product 4-(trans-4'-
alkyloxymethylcyclohexyl)benzoic acid
3″-chloro-4″-cyanophenyl ester ()
is obtained.

In the third step, the compound () is reacted with sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, sodium pentoxide, sodium hexyl oxide, sodium heptyl oxide, and sodium octyl oxide as alcoholates, respectively. 4-(trans-4'-methyloxymethylcyclohexyl)benzoic acid 3''-chloro-4''-cyanophenyl ester 4-(trans-4'-ethyloxymethyl) Cyclohexyl) benzoic acid 3″-chloro-4″-cyanophenyl ester 4-(trans-4′-propyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester 4-(trans-4′) -butyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester 4-(trans-4′-pentyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester 4-( trans-4′-hexyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester 4-(trans-4′-heptyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester Ester 4-(trans-4′-octyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester is obtained. Details of use are described in a non-limiting manner.

Example 1 [Production of 4-(trans-4′-methyloxymethylcyclohexyl)benzoic acid 3″-chloro-4″-cyanophenyl ester] First step: 11.1 g (0.293 mol) of lithium aluminum hydride was dried. Tetrahydrofuran (THF) 420
Add ml of trans-4 and stir vigorously.
-Methyl cyclohexanecarboxylate 64.0g
(0.293 mol) dissolved in 70 ml of THF is added dropwise while keeping the reaction temperature below 20°C. After dripping
Heat to 55°C, react for 2 hours, and cool. Next, add 12 ml of ethyl acetate and 100 ml of water, then add 350 ml of 18% sulfuric acid water to separate into a tetrahydrofuran layer and an aqueous layer. Add 200 ml of n-heptane, transfer to a separatory funnel, wash with 500 ml of water, then wash with 500 ml of 2% aqueous sodium carbonate solution, and further wash with water until the aqueous layer becomes neutral. After n-heptane and THF were distilled off, the solid remaining in the pot was recrystallized with 20 ml of n-heptane, separated, and the crystals were dried to obtain 51.4 g of 4-phenylcyclohexylmethanol ().
Melting point 47.3-48.5℃.

Second stage Compound () obtained in the first stage 50g (0.268
mol) was dissolved in 110 ml of dry pyridine and cooled to below 5°C. Then, a solution of 50.1 g (0.263 mol) of p-toluenesulfonic acid chloride dissolved in 70 ml of dry toluene was poured into the dropping funnel so that the reaction temperature did not exceed 10°C. Drip small amounts at a time. When the addition is complete, remove the cold bath and stir at room temperature for 4 hours, then add 100ml of water.
Add 300ml of toluene and stir. Transfer it to a separatory funnel, and add the toluene layer twice with 100ml of 6N-HCl water, then once with 200ml of water, and then with 100ml of 2N-NaOH aqueous solution.
The toluene was distilled off under reduced pressure.
ml and dried separately to obtain 77.0 g of trans-4-phenylcyclohexylmethyl p-toluenesulfonate (). Melting point 108.0~
108.7℃.

3rd step Stir 250ml of methyl alcohol at room temperature,
Add 17.4 g (0.755 mol) of metallic sodium cut into small pieces little by little to make sodium methoxide. Compound (200.0g (0.581 mol) obtained after the metallic sodium pieces are gone)
A solution dissolved in 600 ml of dry toluene is gradually added from a dropping funnel so that the internal temperature remains within the range of 50 to 60°C. After the dripping is complete, reflux for 4 hours, cool, and add 20 ml of water.
ml, transfer to a separatory funnel, and wash the toluene layer with water until the aqueous layer becomes neutral. Distill toluene under reduced pressure and then distill under reduced pressure to obtain a boiling point of 105-108
C/1.5 mmHg fractions were collected to obtain 100.0 g of trans-4-methyloxymethyl-1-phenylcyclohexane ().

4th stage 100.0g (0.489 mol) of the compound () obtained in the 3rd stage, 344ml of acetic acid, 91ml of water,
Iodic acid 20.6g (0.117mol), iodine 54.5g
(0.215 mol), 40 ml of carbon tetrachloride, and 14 ml of concentrated hydrochloric acid were added, stirred, and further heated with a mantle heater and refluxed for 3 hours. 10% sodium thiosulfate water after cooling 15
ml to eliminate the color of excess iodine. Add 200ml of n-heptane, transfer to a separatory funnel, wash the n-heptane layer with water until the aqueous layer becomes neutral, distill off the n-heptane under reduced pressure, and remove the residue with 50ml of n-hexane.
After dissolving it in the solution, it was left at -10 to -20℃ for 12 hours, the resulting crystals were separated, and the crystals were dried to obtain 81.3 g of 4-(trans-4'-methyloxymethylcyclohexyl)iodobenzene (). . Melting point 40.3
~42.3℃.

5th step 20.0g (0.061 mol) of the compound () obtained in the 4th step and cuprous cyanide in a 300ml three-necked flask
Add 6.3 g (0.071 mol) and 63 ml of N,N-dimethylformamide (DMF), stir, and heat with a mantle heater to reflux for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, 18 ml of 28% ammonia water was added, stirred, and extracted with 50 ml of n-heptane.
After removing insoluble matter in the heptane layer by filtration, 6N
-Wash with 50ml of HCl, then with 50ml of 2N-NaOH aqueous solution, and then with water until neutral. It was concentrated under reduced pressure, and the resulting crude crystals were recrystallized from 10 ml of ethanol and dried separately to obtain 4-(trans-4'-methyloxymethylcyclohexyl).
6.4 g of benzonitrile () was obtained.

6th step 25g (0.109 mol) of the compound () obtained in the 5th step and ethylene glycol in 2 three-necked flasks
Add 722 ml of KOH dissolved in 26 ml of water, then heat with a mantle heater and reflux for 12 hours. After cooling
Add 200ml of 6N-HCl to make it acidic and crystals will form. The crystals were separated, dried, dissolved in 200 ml of ethanol, and recrystallized to obtain 18.8 g of 4-(trans-4'-methyloxymethylcyclohexyl)benzoic acid (). Melting point (C
-N point) is 182.7℃, clearing point (N-I point) is 234.6
It was warm at ℃.

7th stage Compound () obtained in the 6th stage 18.8g
Add 20 ml of thionyl chloride to (0.076 mol) and heat in a water bath at 60-80°C for 4 hours. Once the mixture became homogeneous, it was left to stand for another hour, and then the pressure was reduced to completely distill off excess thionyl chloride, leaving an oily substance. This is 4-(trans-4'-methyloxymethylcyclohexyl)benzoic acid chloride ().

8th stage 3-chloro-4-cyanophenol 0.6g
(0.004 mol) and 1 g (0.004 mol) of the compound () obtained in step 7 dissolved in 2 ml of dry pyridine.
mol) while stirring vigorously. After leaving the reaction solution overnight, add 10 ml of water and then add 50 ml of toluene for extraction. The toluene layer is washed with 6N-HCl, then with 2N-NaOH aqueous solution, and then with water until it becomes neutral. The toluene solution was distilled off under reduced pressure, and the resulting crude crystals were recrystallized with 10 ml of ethanol and dried separately to obtain the desired 4-(trans-4'-methyloxymethylcyclohexyl)benzoic acid 3''-chloro-4''-cyano. 0.5 g of phenyl ester was obtained. The melting point (CN point) of this product was 99.4°C, and the clearing point (NI point) was 137.0°C. Furthermore, the elemental analysis values of this compound are in good agreement with the calculated values as shown below.

Actual value (%) Calculated value (%) (as C ₂₂ H ₂₂ NClO ₃ ) C 68.8 68.88 H 5.7 5.78 N 3.6 3.65 Cl 9.21 9.24 Examples 2 and 3 Substitute for methyl alcohol in the third step in Example 1 The following compound was obtained in the same manner as in Example 1 using ethyl alcohol and propyl alcohol.

4-(trans-4'-ethyloxymethylcyclohexyl)benzoic acid 3''-chloro-4''-cyanophenyl ester (C-N point) 92.4-93.7°C, (N-I point) 103.6°C.

4-(trans-4'-propyloxymethylcyclohexyl)benzoic acid 3''-chloro-4''-cyanophenyl ester (C-N point) 75.3-76.3°C, (N-I point) 89.8°C.

Example 4 (Usage example) The nematic liquid crystal temperature range (MR) of the liquid crystal composition consisting of is -3 to 52.5℃, and the viscosity η ₂₀ at 20℃ is
23cp, dielectric anisotropy △ε is 11.3 (ε=16.2, ε⊥
= 4.9), and when this was sealed in a TN cell with a cell thickness of 10 μm, the threshold voltage was 1.5V and the saturation voltage was 2.2V.

To this composition, one of the compounds of the present invention, Example 3, was added. The MR of the liquid crystal composition to which ₁₅ parts of
21.0, ε⊥=5.4), and when sealed in the same cell as above, the threshold voltage was 1.31V and the saturation voltage was 1.8V.

Claims (1)

[Claims] 1. General formula (R in the above formula represents an alkyl group having 1 to 5 carbon atoms)
4-(trans-4′-alkyloxymethylcyclohexyl)benzoic acid 3″-chloro-
4″-cyanophenyl ester. 2 General formula (R in the above formula represents an alkyl group having 1 to 5 carbon atoms)
4-(trans-4′-alkyloxymethylcyclohexyl)benzoic acid 3″-chloro-
A liquid crystal composition containing at least one 4″-cyanophenyl ester.