JPS59196854A - Ester of 4-alkyl-2-cyanophenol - Google Patents

Abstract

NEW MATERIAL:The trans-4-[ 4-( trans-4-alkylcyclohexyl )phenyl ]cyclohexanecarboxylic acid 2-cyano-4-alkylphenyl ester of formula I (R and R' are 1-15C alkyl). EXAMPLE:A liquid crystal composition having negative dielectric anisotropy and high clear point, and exhibiting liquid crystal phase over a wide temperature range. PREPARATION:The compound of formula I can be prepared by reducing 4-(trans- 4-alkylcyclohexyl)-biphenyl-4'-carboxylic acid of formula II with metallic sodium in isoamyl alcohol, converting the resultant compound of formula III to the acid chloride of formula IV with SOCl2, and reacting the chloride with 2-cyano- 4-alkylphenol in the presence of pyridine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 4-alkyl-2-cyanphenol esters and compositions thereof, and relates to a novel liquid crystal compound having negative dielectric anisotropy and a liquid crystal composition containing the same.

Liquid crystal display devices utilize the optical anisotropy and dielectric anisotropy of liquid crystal materials, and depending on the display format, there are TN type (
There are various types such as twisted nematic type (twisted nematic type), DS type (dynamic scattering type), guest-host type, and DAP type, and the properties of the liquid crystal materials suitable for each use are different. It is common for all liquid crystal materials to be stable against moisture, air, heat, light, etc., and there is a need for materials that exhibit a liquid crystal phase over as wide a temperature range as possible, centered around room temperature. There is.

At present, there is no single compound substance that satisfies these conditions, and a liquid crystal composition obtained by completely mixing several types of liquid crystal compounds and non-liquid crystal compounds is used.

Recently, guest display, which is a color LCD display method, has been
Host-type liquid crystal display devices have started to attract a lot of attention. This uses a mixture of liquid crystal and color chromatography, and the positive guest-host type display element uses liquid crystal with a negative dielectric anisotropy value, and the liquid crystal has various properties as its constituent components. There is a need for liquid crystal compounds with good compatibility and negative dielectric anisotropy.

An object of the present invention is to provide a novel liquid crystal compound suitable for such uses.

That is, the present invention provides trans-4-(4-()trans-4- The present invention relates to esters of 4-alkyl-2-cyanphenol using alkylcyclohexyl) phenylcocyclohexanecarboxylic acid-2-cyano-4-alkylphenyl ester, and a liquid crystal composition containing all of them.

The compounds of the present invention have high clearing points, such as trans-4-(4-()trans-4), which is one of the compounds of the present invention.
-Crystalline nematic point (hereinafter abbreviated as C-N point) of -pentylcyclohexyl)phenylcocyclohexanecarboxylic v-2-cyano-4-hegtylphenyl ester.

) is 99.1°C, nematic clearing point (hereinafter N-1
Abbreviated as dot. ) exhibits a liquid crystal phase over a wide temperature range of 199.2°C, and by adding it as a component to a liquid crystal composition, it is possible to raise the clearing point without increasing the viscosity of the liquid crystal composition. I can do it. Furthermore, the dielectric anisotropy value (
Hereinafter, it will be abbreviated as Δε. , , ) is about -3, so by mixing it with other nematic liquid crystals, it is possible to obtain a liquid crystal composition having negative dielectric anisotropy that can be used for guest-host type display devices. In addition, by combining it with one having a positive dielectric anisotropy value, it can be used in a p two-frequency method type display element.

Next, a method for producing the compound of the present invention will be described. First, 4-(+・lance-4,-furkylcyclohexyl)biphenylyl-
4-fucarboxylic acid (compound mark) is reduced with metallic sodium in inoamyl alcohol to obtain trans-4-C
4-Ctrans-4-alkylcyclohexyl)phenylcocyclohexanecarboxylic acid (compound volume)) is obtained.

Next, compound (1) was made into an acid chloride (compound (IV)) with thionyl chloride, and reacted with 2-cyano-4-alkylphenol in the presence of pyridine to obtain the desired trans-4
-(4-()lans-4-alkylcyclohexyl)phenyl)cyclohexanecarboxylic acid-2-cyano-4-
Alkylphenyl ester (compound (1)) can be produced.

The above chemical formula is expressed as follows:

Example 1 trans-4-(4-(1-trans-4-pentylcyclohexyl)phenyl)cyclohexanecarboxylic acid-2
-cyano-4-heptyl phenyl ester (compound% 71
(1) Trans-4-(4-(trans-
Production of 4-pentylcyclohexyl)phenylcocyclohexanecarboxylic acid (compound Gl) 4, -(trans-4-pentylcyclohexyl)biphenylyl-4'
-Carvone I'FR (compound Gl) ) 10y total inamyl alcohol 2500 tt! Stir with l;
Heated at 90°C. Next, metallic sodium 809 was added to cause a vigorous reaction.

It takes 3 hours to continue to reflux the metal) I
When an additional 120 g of Jum was added, the reaction solution gradually became homogeneous. After the reaction was completed, the mixture was allowed to cool to 100°C.

Next, isoamyl alcohol was distilled off while adding water.

Next, 2000wt1 of water-i was added. Then 6N-H
Add Ct2# to make it completely acidic, and remove the precipitated V by filtration.
Washed with water. Then, it was recrystallized using acetic acid to obtain trans-4
-(4-() lance-4-pentylcyclohexyl)
phenyl)cyclohexanecarboxylic acid (compound 11))
Obtained 4.5y. This carboxylic acid also exhibits liquid crystallinity, and its crystalline smectic point (hereinafter abbreviated as C-3 point) is 289.1°C, and the smectic clearing point (hereinafter referred to as S-I point) is 289.1°C.
Abbreviated as dot. ) was 274.3°C (accompanied by decomposition).
showed that.

(2) Esterification Trans-4-(4-(trans-4~pentylcyclohexyl)phenylcocyclohexanecarboxylic! (compound side)) 0.68f produced in the above (1) is fused with thionyl chloride 10 at 80° with t. It was heated to C. The reaction solution is 1
The mixture became homogeneous over time, and the reaction was continued for an additional hour. Excess thionyl chloride was then distilled off under reduced pressure to leave an oily acid chloride. Separately, 0.43 y of 2-cyano-4-hebutylphenol was dissolved in 5 ml of pyridine, and the above-mentioned acid chloride was added thereto with stirring.

After the reaction, 50 ml of toluene was added and the mixture was poured into water. The toluene layer separated into layers was treated with 6N-HCL,
A solution of 2N-Na0I was then washed with water and finally dried using anhydrous sodium sulfate.Then, toluene was distilled off under reduced pressure to obtain a crystal, which was recrystallized with ethyl acetate to obtain the desired product. trans-4-(4-(trans-4-pentylcyclohexyl)phenyl)cyclohexanecarboxylic acid-2-cyano-4-heptylphenyl ester (compound (1)) 0.6 i y (yield 57.7 %) was obtained.The C-N point of this was 99.1°
C, N-I point was 199.2°C.

Example 2 (Usage Example) The N-I point of an ester-based nematic liquid crystal composition (Rixon FN-45 manufactured by Chisso) was G-224 manufactured by Merck & Co.
,) was added at 1% by weight, and the distance between the opposing transparent electrodes was 1%.
A complete guest/host cell was made by sealing it in a 0 μm cell, and the threshold voltage was measured to be 3.80V.

Next, the compound of the present invention, trans-4-(4-()
10 parts by weight of lance-4-heptylcyclohexyl)phenylcocyclohexanecarboxylic acid-2-cyano-4-hebutylphenyl ester was added to the liquid crystal composition (F'N-4).
5) A liquid crystal composition was prepared by mixing 90 parts by weight. The N-I point of the composition is 75.0'C, Δε is -1, 1, 20
The viscosity at °C was 24.4 cp, and a guest-host type liquid crystal cell was made by adding 1% by weight of dye G-224 to this cell and sealing it in the same cell as above, and measuring its threshold voltage. As a result, the voltage dropped significantly to 8.40V.

that's all

Claims (1)

[Scope of Claims] (]) trans-IL[:4-(trans-4-
Esters of 4-alkyl-2-cyanophenol with alkylcyclohexyl) phenylcocyclohexanecarbonate-2-cyano-4-alkylphenyl ester. (2) trans-4-(4-()trans-4-alkylcyclohexyl)phenylcocyclohexane carbon t represented by the general formula (in the above formula, R and R' represent an alkyl group having 1 to 15 carbon atoms) A liquid crystal composition comprising an ester of 4-f-alkyl-2-cyanphenol, where i=2-2-cyano-4-alkylphenyl ester.