JPS5934169B2 - 4-Substituted-β-methylcinnamic acid 4'-substituted phenyl ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel organic compound, and more particularly to a novel nematic liquid crystal material, 4-substituted-β-
It relates to methyl cinnamic acid 4' monosubstituted phenyl ester.

Nematic liquid crystal materials are considered to be applicable to electronic display elements, and various nematic liquid crystal materials have been proposed.

Among the nematic liquid crystal materials proposed so far, Schiff base compounds are room temperature nematic liquid crystal materials and are the most commonly used. However, these Schiff base compounds are extremely unstable in the presence of water and ultraviolet light, and must be handled with great care.

The present invention is based on the search for a new nematic liquid crystal material in view of this conventional drawback. The present invention is based on the general formula R10C=7-C-00R2 (wherein R1 and R2 are n-alkyl group [CH3(CH2)l] or n-alkoxy group [CH3
(CH2)mO].

However, when 6~8, m=0~7, R1 and R2 are n at the same time.
-Not an alkyl group. In the following specification, R1, R
2 is the same. It has been found that the 4-substituted mono-β-methylcinnamic acid 4'-monosubstituted phenyl ester represented by ) exhibits a nematic liquid crystal phase at or near room temperature in many cases at a relatively low temperature. In addition, these compounds are more stable in the atmosphere than the Schiff base compounds mentioned above, and by mixing several types of these compounds or by mixing them with other nematic liquid crystal materials, they can be used over a wider range than the individual components. A mixed liquid crystal exhibiting a nematic liquid crystal phase was obtained, and this compound was found to be extremely useful in applications such as electronic display devices. The above compounds of the present invention are novel;
It is synthesized according to the following formula.

That is, a 4-monosubstituted acetophenone and ethyl bromoacetate were subjected to a RefOrmatoski reaction in the presence of zinc.
tsky) to form 2-hydroxy-2-
Ethyl (4-monosubstituted phenyl)-propionate was obtained.

This compound (1) was dehydrated using potassium hydrogen sulfate and then hydrolyzed to obtain trans-4-substituted monoβ-methylcinnamic acid.

This compound n) is reacted with thionyl chloride and then with 4-monosubstituted phenol to obtain the target product, trans-4-monosubstituted mono-β-methylcinnamic acid 4'-monosubstituted phenyl ester.

Examples are shown below.

Examples 1 to 10 A mixed solution of 0.061 mol of 4-substituted acetophenone, 0.05 mol of ethyl bromoacetate, 8 ml of benzene and 2 ml of ether is gradually dropped into 4.0 y of zinc under a nitrogen atmosphere.

At this time, the reaction solution is heated to a point where it slightly refluxes. Reflux is continued for 4 hours after the completion of the dropwise addition. The reaction solution is cooled, 10% sulfuric acid water is added, and the organic layer is washed with 5% sulfuric acid water and water. The aqueous layer is extracted with ether, added to the organic layer, and dried over sodium sulfate. Compound (1) is obtained by distilling off the solvent. Add several grams of potassium hydrogen sulfate to compound (4) and heat at 100 to 150°C under a reduced pressure of 10 to 20 m7nHg.
The mixture is heated for several hours to carry out the dehydration reaction. After filtering potassium hydrogen sulfate from the reaction solution, it was heated with ethanol, water, and sodium hydroxide to perform hydrolysis. After adding hydrochloric acid water to this solution, the product was separated by filtration and recrystallized from ethanol to obtain Compound (A) in a yield of 30 to 40%.
Compound 01) was then reacted with thionyl chloride in carbon tetrachloride under reflux, and the acid chloride derivative obtained by distilling off the solvent was reacted with an equivalent amount of phenol in benzene using pyridine. The benzene solution was chromatographed on alumina (activity -). After distilling off benzene, recrystallize from n-hexane to obtain 80-90% of the target product.
Obtained in ~90% yield. Table 1 shows the novel liquid crystal compounds according to the present invention and the temperature ranges at which they become liquid crystals, and all of these compounds were enantiotropic nematic liquid crystals. Note that the temperature range at which liquid crystal is formed was measured using a polarizing microscope equipped with a hot stage. Example 1 of the present invention
The infrared absorption spectra of the new compound corresponding to No. 16 are shown in FIGS. 1 to 16.

In Table 1, column R-R2 indicates the liquid crystal phase transition temperature of the compound, and column B indicates the monoisotropic liquid phase transition temperature of the nematic liquid crystal phase.

Example 17 The temperature range in which the equivalent weight mixture of the compounds obtained in Examples 3, 5, and 7 became nematic liquid crystal was 16 to 69°C, and it was nematic liquid crystal at room temperature.

This mixed liquid crystal was exposed to 60°C in the atmosphere for 10 hours, but there was no change in color, and the transition temperature from the nematic liquid crystal phase to the isotropic liquid phase was 69°C, and no change was observed. Comparative Example 1 P-methoxybenzylidene-P! - When a Schiff base liquid crystal consisting of an equal weight mixture of n-butylaniline and P-ethoxybenzylidene-P'-n-butylaniline was exposed to the air at room temperature for about 10 minutes, it showed a nematic liquid crystal phase and a monoisotropic liquid. The transition temperature to phase was 57°C from 61°C before exposure.
℃ dropped by 4℃.

This fact indicates that the compound of the present invention is more stable in the atmosphere than Schiff base salt crystals.

[Brief explanation of the drawing]

Figures 1 to 16 show novel compounds 4 according to the present invention.
FIG. 2 is an infrared absorption spectrum diagram of a monosubstituted β-methylcinnamic acid l monosubstituted phenol ester.

Claims (1)

[Claims] 1 General formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ {In the formula, R_1 and R_2 are n-alkyl groups [CH_3(
CH_2)_l] or n-alkoxy group [CH_3
(CH_2)_mO]. However, l=6 to 8, m=0 to 7, and R_1 and R_2 are not n-alkyl groups at the same time. ) 4-substitution-
β-Methylcinnamic acid 4'-substituted phenyl ester.