JPH04217665A - Branched phenylpyridine compound and liquid crystal composition containing the same - Google Patents

Abstract

PURPOSE:To provide the title novel compound useful as a component for ferroelectric liquid crystal materials capable of realizing quick response. CONSTITUTION:The objective compound of formula I (X and Y are each H or methyl, except that they are H at the same time; m and n are each 4-20; Z is carbonyl or methylene), for example, 5-(6methylheptanoyl)-2-(4-heptylphenyl) pyridine. The present compound can be obtained by the following process: a reaction is made between a substituted acetophenone of formula II and a formate, and the resulting product is reacted with cyanoacetamide into a pyridone of formula III, which is then converted to its chlorinated modification followed by dechlorination into a cyano modification of formula IV, which is then reacted with a Grignard reagent.

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel compound useful as a ferroelectric liquid crystal material and a liquid crystal composition containing the same. 2. Description of the Related Art A twisted nematic (TN) type is a typical display system for liquid crystal display devices that is currently in widespread use. However, this system using a nematic liquid crystal phase has problems such as slow response speed and inferior viewing angle characteristics compared to display systems such as CRT, and its use as a display has been limited. Recently, a display system using ferroelectric liquid crystals has been reported by Clark and Lagerwell et al. (Japanese Patent Application Laid-open No. 56-107216, US Pat. It is attracting attention as a next-generation liquid crystal display element because it is capable of creating a bistable state with responsiveness and memory properties, and also has excellent viewing angle characteristics. One of the liquid crystal phases of ferroelectric liquid crystal is a chiral smectic C (hereinafter abbreviated as SC*) phase. In order to use it as a display element, a wide range of S
Although many characteristics are required, such as having a C* phase and high-speed response, there is no single compound that satisfies these characteristics.
Currently, liquid crystal compositions consisting of several types of compounds are being used. One method for constructing the composition is to add an optically active compound to a liquid crystal compound or liquid crystal composition (hereinafter referred to as base liquid crystal) that exhibits a smectic C (hereinafter abbreviated as SC) phase that does not exhibit ferroelectricity. There is a method (Mol.Cryst.Liq.Cryst., 8
9, 327 (1982)). SC used here
Components of the base liquid crystal exhibiting a phase include liquid crystal compounds such as phenylbenzoate, Schiff base, biphenyl, phenylpyrimidine, and phenylpyridine. In recent years, the following phenylpyrimidine liquid crystal compounds have been actively studied from the viewpoint of SC properties, low viscosity, etc. ##STR2## However, the above-mentioned base liquid crystal is still not at a fully satisfactory level in terms of high-speed response, and further improvements have been desired. SUMMARY OF THE INVENTION An object of the present invention is to provide novel compounds and liquid crystal compositions useful as components of ferroelectric liquid crystal materials that can achieve high-speed response. [Means for Solving the Problems] The above object is to contain a phenylpyridine compound having a branch represented by the following general formula (I) and at least one type of compound of the general formula (I). This problem was solved by developing a liquid crystal composition with the following characteristics. General formula (I) ##STR3## In the formula, X and Y represent hydrogen or a methyl group. However, this excludes the case where X and Y are hydrogen at the same time. m,
n each independently represents an integer of 4 to 20, and Z represents a carbonyl group or a methylene group. [0011] The compound of formula (I) can be produced by various synthetic methods, for example, by the following route. ##STR4## That is, substituted acetophenone (1) and formic acid ester (2) are reacted in the presence of sodium methoxide to form an enolate, which is further reacted with cyanoacetamide to form a pyridone ( 3). Next, this is reacted with phosphorus oxychloride to form the chloride (4), and then dechlorinated to form the cyano form (5). The compound (I) in which Z is a carbonyl group can be produced by reacting this cyano compound (5) with a Grignard reagent. Further, by reducing this compound with hydrazine, the compound (I) in which Z is represented by a methylene group can be produced. As a result of extensive research in the search for a base liquid crystal useful for high-speed response, the present inventors have discovered some compounds of formula (I) in which at least one side chain has an alkyl group or acyl group with a terminal methyl branch. is SC by itself
It has been discovered that the compound exhibits a gradient smectic phase such as the SF phase or the SF phase, and that replacing a part of the base liquid crystal of a ferroelectric liquid crystal composition with the compound contributes to high-speed response without significantly impairing the SC properties of the composition, The present invention has now been completed. As shown in the Examples below, a ferroelectric liquid crystal composition obtained by mixing the liquid crystal compound of the present invention with a ferroelectric liquid crystal material exhibits very good responsiveness. That is, the compound of the present invention is a liquid crystal material useful as a ferroelectric liquid crystal material. Examples of the compounds of the present invention include the following compounds. 5-(6-methylheptanoyl)-2-(4-heptylphenyl)pyridine 5-(7-methyloctanoyl)-2-(4-heptylphenyl)pyridine 5-(8-methylnonanoyl)-2 -(4-Heptylphenyl)pyridine 5-(9-methyldecanoyl)-2-(4-heptylphenyl)pyridine 5-(7-methyloctanoyl)-2-(4-octylphenyl)pyridine 5-(8 -methylnonanoyl)-2-(4-octylphenyl)pyridine 5-(9-methyldecanoyl)-2-(4-octylphenyl)pyridine 5-(8-methylnonanoyl)-2-(4-nonylphenyl)pyridine 5 -(9-methyldecanoyl)-2-(4-nonylphenyl)pyridine5-(10-methylundecanoyl)-2-(4-nonylphenyl)pyridine5-(9-methyldecanoyl)-2- (4-decylphenyl)pyridine 5-(10-methylundecanoyl)-2-(4-decylphenyl)pyridine 5-(11-methyldodecanoyl)-2-(4-decylphenyl)pyridine 5 -octanoyl-2-(4-(6-methylheptyl)
phenyl)pyridine5-nonanoyl-2-(4-(7-methyloctyl)phenyl)pyridine5-decanoyl-2-(4-(7-methyloctyl)phenyl)pyridine5-nonanoyl-2-(4-(8 -methylnonyl)phenyl)pyridine5-decanoyl-2-(4-(8-methylnonyl)phenyl)pyridine5-undecanoyl-2-(4-(8-methylnonyl)
phenyl)pyridine5-decanoyl-2-(4-(9-methyldecyl)phenyl)pyridine5-undecanoyl-2-(4-(9-methyldecyl)
phenyl)pyridine 5-dodecanoyl-2-(4-(9-methyldecyl)phenyl)pyridine 5-(7-methyloctanoyl)-2-(
4-(6-methylheptyl)phenyl)pyridine 5-(
8-Methylnonanoyl)-2-(4-(7-methyloctyl)phenyl)pyridine 5-(9-methyldecanoyl)-2-(4-(7-methyloctyl)phenyl)pyridine 5-(9-methyldecanoyl) Noyl)-2-(4-(8-
methylnonyl)phenyl)pyridine 5-(10-methylundecanoyl)-2-(4-(8-methylnonyl)phenyl)pyridine 5-(9-methyldecanoyl)-2-
(4-(9-methyldecyl)phenyl)pyridine 5-(
10-methylundecanoyl)-2-(4-(9-methyldecyl)phenyl)pyridine 5-(11-methyldodecanoyl)-2-(4-(9-methyldecyl)phenyl)pyridine 5-( 6-Methylheptyl)-2-(4-heptylphenyl)pyridine 5-(7-methyloctyl)-2-(4-heptylphenyl)pyridine 5-(8-methylnonyl)-2-(4-heptylphenyl)pyridine 5-(7-methyloctyl)-2-(4-octylphenyl)pyridine 5-(8-methylnonyl)-2-(4-octylphenyl)pyridine 5-(9-methyldecyl)-2-(4-octylphenyl ) Pyridine 5-(8-methylnonyl)-2-(4-nonylphenyl)pyridine 5-(9-methyldecyl)-2-(4-nonylphenyl)pyridine 5-(10-methylundecyl)-2-(4 -nonylphenyl)pyridine 5-(9-methyldecyl)-2-(4-decylphenyl)pyridine 5-(10-methylundecyl)-2-(4-decylphenyl)pyridine 5-(11-methyldodecyl)- 2-(4-decylphenyl)pyridine 5-octyl-2-(4-(6-methylheptyl)phenyl)pyridine 5-nonyl-2-(4-(7-methyloctyl)phenyl)pyridine 5- Decyl-2-(4-(7-methyloctyl)phenyl)pyridine 5-nonyl-2-(4-(8-methylnonyl)phenyl)pyridine 5-decyl-2-(4-(8-methylnonyl)phenyl)pyridine 5-Undecyl-2-(4-(8-methylnonyl)phenyl)pyridine 5-decyl-2-(4-(9-methyldecyl)phenyl)pyridine 5-undecyl-2-(4-(9-methyldecyl)phenyl) Pyridine 5-dodecyl-2-(4-(9-methyldecyl)phenyl)pyridine 5-(7-methyloctyl)-2-(4-
(6-methylheptyl)phenyl)pyridine 5-(8-
methylnonyl)-2-(4-(7-methyloctyl)phenyl)pyridine 5-(9-methyldecyl)-2-(4
-(7-methyloctyl)phenyl)pyridine 5-(9
-methyldecyl)-2-(4-(8-methylnonyl)phenyl)pyridine 5-(10-methylundecyl)-2
-(4-(8-methylnonyl)phenyl)pyridine 5-
(9-methyldecyl)-2-(4-(9-methyldecyl)phenyl)pyridine 5-(10-methylundecyl)
-2-(4-(9-methyldecyl)phenyl)pyridine 5-(11-methyldodecyl)-2-(4-(9-methyldecyl)phenyl)pyridine [0022] Furthermore, in the general formula (I) of the present invention, The represented compound can be combined with other liquid crystal compounds, but for example, by combining it with at least one of the compounds shown below, a liquid crystal composition having a wide SC phase can be obtained. . In this case, the compound represented by formula (I) is preferably used in an amount of 1 to 99% by weight of the liquid crystal composition obtained. 5-(7-methyloctyl)-2-(4-octylphenyl)pyrimidine 5-(8-methylnonyl)-2-(4-octylphenyl)pyrimidine 5-(9-methyldecyl)-2-(4 -octylphenyl)pyrimidine 5-(8-methylnonyl)-2-(4-nonylphenyl)pyrimidine 5-nonyl-2-(4-(8-methylnonyl)phenyl)pyrimidine 5-decyl-2-(4-(8 -Methylnonyl)phenyl)pyrimidine 5-decyl-2-(4-(9-methyldecyl)phenyl)pyrimidine 5-(9-methyldecyl)-2-(4-(8-methylnonyl)phenyl)pyrimidine 5-(9-methyldecyl )-2-(4-(9-methyldecyl)phenyl)pyrimidine 5-(10-methylundecyl)-2-(4-(9-methyldecyl)phenyl)pyrimidine 5-nonyloxy-2-(4- 5-octyl-2-(4-octyloxyphenyl)pyrimidine 5-nonyl-2-(4-octyloxyphenyl)pyrimidine 5-heptyl-2-(4-nonyloxyphenyl)pyrimidine 5-hexyl- 2-(4-pentylbiphenyl-4'
-) Pyrimidine 5-heptyl-2-(4-pentylbiphenyl-4'
-) pyrimidine 5-octyl-2-(4-heptylbiphenylyl-4'
-) Pyrimidine 5-heptyl-2-(4-heptyloxyphenyl)pyridine 5-heptyl-2-(4-octyloxyphenyl)pyridine 5-heptyl-2-(4-nonyloxyphenyl)pyridine 5- Heptyl-2-(3-fluoro-4-octyloxyphenyl)pyridine 5-(4-heptyloxyphenyl)-2-(4-heptylphenyl)pyridine 5-decyl-2-(4-decanoyloxyphenyl)pyrimidine 4-octyloxyphenyl-4'-decyloxybenzoate 4-octyloxyphenyl-4'-decylbenzoate 4-hexyloxyphenyl-4'-octylbenzoate [0027] Furthermore, compounds represented by general formula (I) and A liquid crystal composition made of a combination with the above compounds can be combined with various optically active compounds, but
For example, a ferroelectric liquid crystal composition can be obtained by combining it with at least one kind of optically active compound as shown below. In this case, the optically active compound shown below is desirably used in an amount of 0.1 to 90% by weight of the resulting liquid crystal composition. 5-octyl-2-[4-((2S)-2
-fluorooctyloxy)phenyl]pyrimidine 5-[(2S)-2-((2S)-2-propyloxypropanoyloxy) propyloxy]-2-(4-octyloxyphenyl)pyrimidine 5-[(2S) -2-((2S)-2-propyloxypropanoyloxy)propyloxy]-2-(4-heptylbiphenylyl-
4'-)pyrimidine 5-((2S)-2-methylbutyl)-2-(4-heptylbiphenylyl-4'-)pyrimidine [Example] Examples are shown below, but the present invention It is not limited. Example 1 5-(9-methyldecanoyl)-2-(4
-decylphenyl)pyridine (in formula (I), X=H
, Y=Me, m=8, n=7, Z=carbonyl group. ) (1) Production of 5-cyano-2-(4-decylphenyl)pyridone In a solution of 59.4 g of sodium methoxide and 3 liters of toluene, 26 g of p-decylacetophenone and 7 ml of ethyl formate were added.
After dropping 8 g, the mixture was stirred at room temperature for 8 hours. In the reaction solution, n
- Add 500 ml of butanol and 1 liter of water, take out the aqueous layer, and remove 84 g of α-cyanoacetamide and aqueous piperidine acetate solution (8 ml of acetic acid + 14 ml of piperidine/50 ml of water)
was added and stirred at 90°C for 2 hours. After cooling to 60℃,
Crystals precipitated by adding acetic acid were filtered and washed with methanol to obtain 153 g of 5-cyano-2-(4-decylphenyl)pyridone. (2) Production of 5-cyano-2-(4-decylphenyl)pyridine 5-cyano-2-(4-decylphenyl)pyridone 15
A solution of 3 g of phosphorus oxychloride and 290 ml of phosphorus oxychloride was heated under reflux for 20 hours. The reaction solution was poured into water and made alkaline with an aqueous sodium hydroxide solution, and then the precipitated crystals were filtered off. The crude crystals were purified by column chromatography and recrystallization to obtain 124 g of 5-cyano-6-chloro-2-(4-decylphenyl)pyridine. Next, in a solution of 100 g of this chloride and 1.5 liters of dimethylformamide,
Zinc powder 63g, sodium iodide 72g, water 8.6g
was added and stirred at 130°C for 5 hours. The reaction solution was filtered, acetic acid was added to the filtrate, extracted with toluene, the solvent was distilled off, and the residue was purified by column chromatography and recrystallization to obtain 5-cyano-2-(4-decylphenyl)pyridine 5.
2.5g was obtained. (3) Production of 5-(9-methyldecanoyl)-2-(4-decylphenyl)pyridine Tetrahydrofuran solution of 1.0 g of magnesium 2
To prepare a Grignard reagent, 30 ml of a solution of 8.8 g of 8-methylnonyl bromide in tetrahydrofuran was added dropwise to 0 ml of the solution.
was added at 40°C and refluxed for 1 hour. The reaction solution was poured into ice water containing diluted hydrochloric acid, extracted with 200 ml of toluene, washed with an aqueous sodium bicarbonate solution, and washed with water, and then the solvent was distilled off. The residue was then purified by column chromatography using chloroform as a solvent and recrystallized from ethanol to obtain the desired 5-(9-methyldecanoyl)-2-(4
4.5 g of -decylphenyl)pyridine was obtained. [0035] This material had a liquid crystal phase, and its phase transition temperature (°C) was as follows. Cr74.9S
C 94.5 SA 100.7 I Example 2 5-(9-methyldecyl)-2-(4-octylphenyl)pyridine (in formula (I), X=H, Y=Me, m
=6, n=7, Z=methylene group. )0037]
The reaction was carried out in the same manner as in Example 1, except that p-octylacetophenone was used instead of p-decylacetophenone in Example 1, and 5-(9-methyldecanoyl)-2-(4- Octylphenyl)pyridine was obtained. Add 2.2 g of this compound to 2.2 g of hydrazine monohydrate.
5 g of potassium hydroxide, and 50 ml of diethylene glycol were added thereto, and the mixture was stirred at 120°C for 1 hour and then at 200°C for 2 hours. Pour the reaction solution into ice water and add 100% toluene.
After washing with water, the solvent was distilled off. The residue was then purified by column chromatography using a mixed solvent of hexane/ethyl acetate (20/1) and recrystallized from ethanol to obtain the desired 5-(9-methyldecyl)-2-(4-octylphenyl). ) pyridine 1
．． Obtained 0g. This material had a liquid crystal phase, and its phase transition temperature (°C) was as follows. Cr25.6S
F 58.9 I [0039] Example 3 The reaction was carried out in the same manner as in Example 2, except that 7-methyloctyl bromide was used instead of 8-methylnonyl bromide, and the following compound was prepared. I got it. 5-(8-methylnonyl)-2-(4-octylphenyl)pyridine (in formula (I), X=H,
Y=Me, m=6, n=6, Z=methylene group. )
[0041] This material had a liquid crystal phase, and its phase transition temperature (°C) was as follows. Cr3.9S
F 45.7 SA 49.0 I Example 4 16% by weight of 5-(9-methyldecanoyl)-2-(4-decylphenyl)pyridine of Example 1, which is a compound of the present invention, and the following: A liquid crystal composition consisting of a compound group represented by chemical formula 5 is SC * ⇔ SA: 50.5°C, SA ⇔
I: showed a phase transition temperature of 77.7°C. ##STR5## This composition was injected into a 2 μm thick cell equipped with a transparent electrode coated with polyimide as an alignment treatment agent and subjected to parallel treatment by rubbing the surface. When the device was placed between two orthogonal polarizers and an electric field was applied, changes in transmitted light intensity were observed due to the application of ±5 V. When the spontaneous polarization value Ps was determined from the change in transmitted light intensity at this time using the response time and the triangular wave method, it was as follows. Temperature Response time Ps 25
°C 41.0μs
27.7nC/cm2 0046
Example 5 Consisting of 16% by weight of 5-(9-methyldecyl)-2-(4-octylphenyl)pyridine of Example 2, which is a compound of the present invention, and a group of compounds represented by chemical formula 5 of Example 4 The liquid crystal composition is SC*⇔SA: 54.3°C
, SA⇔I: exhibited a phase transition temperature of 70.2°C. Further, the response time Ps of this composition was determined as follows. Temperature Response time Ps 25
°C 48.8μs
26.8nC/cm2 [0048] Comparative Example A composition consisting of the compound group represented by the following chemical formula 6 is SC
*⇔SA: 56.5℃, SA⇔I: 74.1℃
showed a phase transition temperature of ##STR6## Further, the response time, Ps, of this composition was determined as follows. Temperature Response time Ps 25
℃ 62.0μs
28.4nC/cm2 [Effects of the Invention] The present invention provides a novel compound,
By using the compound in combination with a ferroelectric liquid crystal material, a ferroelectric liquid crystal composition with improved responsiveness can be provided without significantly impairing the SC properties of the composition.

Claims (2)

[Claims] 1. A phenylpyridine compound having a branch represented by the following general formula (I). General formula (I) [Formula 1] In the formula, X and Y represent hydrogen or a methyl group. however,
Except when X and Y are hydrogen at the same time. m and n each independently represent an integer of 4 to 20, and Z represents a carbonyl group or a methylene group. 2. A liquid crystal composition comprising the branched phenylpyridine compound according to claim 1.