JPH04288058A - Phenylpyridine compound and liquid crystal composition containing the same - Google Patents

Abstract

PURPOSE:To provide a new compound useful as a component for ferroelectric liquid crystal material capable of realizing high-speed response. CONSTITUTION:The compound of formula I (R<1> is 7-15C alkyl; R<2> is 6-15C alkoxymethyl), e.g. 5-hexyloxymethyl-2-(4-heptylphenyl)pyridine. The compound of formula I can be produced by reacting a substituted acetophenone of formula II with a formic acid ester in the presence of sodium methoxide, reacting the obtained enolate with cyanoacetamide to form a pyridone compound, reacting the compound with phosphorus oxychloride, dechlorinating the obtained chlorine compound, hydrolyzing the resultant cyano compound to form an ester compound of formula III and finally reducing and etherifying the ester compound.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel liquid crystal compound useful as a ferroelectric liquid crystal material.

(Prior Art) Twisted nematic (TN) is a typical display system for liquid crystal display devices that is currently widely used. 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 crystal has been reported by Clark and Lageruer et al.
216, U.S. Patent No. 4,367,924, etc.), ferroelectric liquid crystals are capable of producing a bistable state with high-speed response and memory properties, and have excellent viewing angle characteristics. It is attracting attention as a new generation of liquid crystal display elements.

One of the liquid crystal phases of ferroelectric liquid crystal is a chiral smectic C (hereinafter abbreviated as Sc*) phase. In order to be used as a display element, many characteristics are required, such as having a wide range of Sc* phases and high-speed response, but no single compound can satisfy these characteristics, so liquid crystal compositions made of several types of compounds are required. The current situation is that we are dealing with this. 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.Crys
t. Liq, Cryst. , 89, 327 (1982)
). Components of the base liquid crystal exhibiting the Sc phase used here include phenylbenzoate-based, Schiff base-based, biphenyl-based, phenylpyrimidine-based, phenylpyridine-based liquid crystal compounds, and the like. In recent years, the following phenylpyrimidine-based liquid crystal compounds have been actively studied from the viewpoints of Sc properties, low viscosity, and the like.

However, even with the above-mentioned base liquid crystal, it is still not at a fully satisfactory level in terms of contribution to high-speed response.
Further reduction in viscosity was desired.

Furthermore, with respect to the skeleton represented by the formula (I), no skeleton having an Sc phase other than one in which the benzene ring side is substituted with an alkoxy group has been found.

(Objective of the Invention) An object of the present invention is to provide a novel liquid crystal compound useful as a component of a ferroelectric liquid crystal material capable of realizing high-speed response.

(Means for Solving the Problems) The above-mentioned object is based on the general formula (I) [In the formula (I), R1 represents an alkyl group having 7 to 15 carbon atoms, and R2 represents an alkoxymethyl group having 6 to 15 carbon atoms. represents a group. ], and a phenylpyridine compound represented by the general formula (
The problem was solved by developing a liquid crystal composition characterized by containing at least one type of compound I).

As a result of intensive research in the search for Sc-phase liquid crystals, the present inventors found that by substituting the pyridine ring side with an alkoxymethyl group in formula (I), even if the benzene ring side is substituted with an alkyl group, some of the indicates the Sc phase, and S
By replacing a portion of the base liquid crystal of a ferroelectric liquid crystal composition with the compound, including those that do not exhibit a c-phase, the viscosity can be reduced without significantly impairing the Sc properties of the composition, contributing to faster response. This discovery led to the completion of the present invention. That is, the liquid crystal compound of the present invention is a liquid crystal material useful as a ferroelectric liquid crystal material.

The compound of formula (I) can be synthesized in various ways, but
For example, it can be manufactured by the following route.

Namely, substituted acetophenone (1) and formate ester (2)
and 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). This cyano body (5)
The compound (I) can be produced by hydrolyzing the ester compound (6) and then reducing and etherifying it.

Examples of the compounds of the present invention include the following compounds.

5-hexyloxymethyl-2-(4-heptylphenyl)pyridine 5-heptyloxymethyl-2-(4-heptylphenyl)pyridine 5-octyloxymethyl-2-(4-heptylphenyl)pyridine 5-nonyloxymethyl -2-(4-heptylphenyl)pyridine 5-decyloxymethyl-2-(4-heptylphenyl)pyridine 5-heptyloxymethyl-(4-octylphenyl)
Pyridine 5-octyloxymethyl-(4-octylphenyl)
Pyridine 5-nonyloxymethyl-(4-octylphenyl)Pyridine 5-octyloxymethyl-2-(4-nonylphenyl)Pyridine 5-nonyloxymethyl-2-(4-nonylphenyl)
Pyridine 5-decyloxymethyl-2-(4-nonylphenyl)
Pyridine 5-decyloxymethyl-2-(4-decylphenyl)
Pyridine 5-undecyloxymethyl-2-(4-decylphenyl)pyridine (Example) Examples are shown below, but the present invention is not limited thereto.

Example 1, 5-heptyloxymethyl-2-(4-heptylphenyl)pyridine (in formula (1), R1=n-C7H1
5, R2 = n-C7H15OCH2) (1) Production of 5-cyano-2-(4-heptylphenyl)pyridone In a solution of 59.4 g (1 mol) of sodium methoxide and 31 toluene, 218 g of 4-heptylacetophenone (
After dropping 78 g (1.05 mol) of ethyl formate, the mixture was stirred at room temperature for 8 hours. Add 500 ml of n-butanol and 1 liter of water to the reaction solution, take out the aqueous layer, add 84 g (1 mol) of α-cyanoacetamide and piperidine acetate (8 ml of acetic acid + 14 ml of piperidine/50 ml of water),
The mixture was stirred at 90°C for 2 hours. After cooling to 60° C., acetic acid was added and the precipitated crystals were filtered off, washed with methanol, and dried to obtain 153 g (52%) of 5-cyano-2-(4-heptylphenyl)pyridone.

(2) Production of 5-cyano-2-(4-heptylphenyl)pyridine 5-cyano-2-(4-heptylphenyl)pyridone 1
53 g (0.52 mol), 290 ml of phosphorus oxychloride (
A solution of 3.12 mol) 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, and the 5-
124 g (77%) of cyano-6-chloro-2-(4-heptylphenyl)pyridine was obtained. Next, 100 g (0.32 mol) of this chloride and 1.0 g of dimethylformamide were added.
63 g (0.96 mol) of zinc powder, 72 g (0.48 mol) of sodium iodide, 8.6 g (0.0 mol) of water in 5 liters of solution.
．． 48 mol) was added thereto, and the mixture was 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-heptylphenyl)pyridine. 5g (59%) was obtained.

(3) Production of 5-methoxycarbonyl-2-(4-heptylphenyl)pyridine 5-cyano-2-(4-heptylphenyl)pyridine 6
g (0.022 mol) in a solution of 60 ml of ethanol,
Sodium hydroxide 2.6g (0.065 mol), water 20
ml and refluxed for 45 minutes. The reaction solution was poured into warm water and filtered, then hydrochloric acid was added to the filtrate, and after cooling, the precipitated crystals were separated by filtration and dried to yield 5.79 g of 5-hydroxycarbonyl-2-(4-heptylphenyl)pyridine.
I got it. Next, 7.52 g (0.04 mol) of methyl-p-toluenesulfonate was added to a solution of 5.79 g (0.02 mol) of this carboxylic acid, 5.58 g (0.04 mol) of potassium carbonate, and 80 ml of dimethylacetamide. The mixture was stirred at 100°C for 1 hour. The reaction solution was poured into ice water, the precipitated crystals were filtered, and 5-methoxycarbonyl-2-(4
6.2 g of -heptylphenyl)pyridine were obtained.

(4) Production of 5-heptyloxymethyl-2-(4-heptylphenyl)pyridine Lithium aluminum hydride 0.77g (0.0
100 ml of a tetrahydrofuran solution containing 6.1 g (0.02 mol) of 5-methoxycarbonyl-2-(4-heptylphenyl)pyridine was added dropwise to 20 ml of a tetrahydrofuran solution of 2 mol) under ice cooling. After completion of dripping, 10-2
After stirring at 0°C for 1 hour, the reaction solution was poured into a cold aqueous acetic acid solution, extracted with ethyl acetate, the solvent was distilled off, and the remaining amount was purified by column chromatography to obtain 5-hydroxymethyl-2-(4- 4.2 g (7 heptyl phenyl) pyridine
3%). Then sodium hydride (7.1
mmol) in 10 ml of tetrahydrofuran solution, 5-
A solution of 1 g (3.5 mmol) of hydroxymethyl-2-(4-heptylphenyl)pyridine in 10 ml of tetrahydrone furan was added dropwise under ice cooling. After stirring for 1 hour at the same temperature, 1
A solution of 0.95 g (4.2 mmol) of iodoheptane in 20 ml of dimethylformamide was added dropwise.

After stirring at room temperature for 3 hours, the reaction solution was poured into cold hydrochloric acid solution and extracted with toluene. After distilling off the solvent, the residue was purified by column chromatography and recrystallized from ethanol to give 5-heptyloxymethyl-2-( 0.72 g of 4-heptylphenyl)pyridine was obtained.

This material had a liquid crystal phase, and its phase transition temperature was as follows.

300MHz H-NMR spectrum of the obtained 5-decyl-2-(4-heptylphenyl)pyridine (solvent:
CDCl3, internal standard substance: TMS) is shown in FIG.

Example 2 The reaction was carried out in the same manner as in Example 1 except that 1-bromodecane was used instead of 1-iodoheptane in Example 1 to obtain the following target compound.

5-decyloxymethyl-2-(4-heptylphenyl)pyridine Example 3, consisting of 16% by weight of 5-heptyloxymethyl-2-(4-heptylphenyl)pyridine of Example 2, which is a compound of the present invention The mixture (hereinafter abbreviated as composition A) is S
It showed a phase transition temperature of c*■SA: 49.4°C and SA■1: 64.5°C. This composition A was applied with polyimide as an alignment treatment agent, and injected into a 2 μm thick cell equipped with a transparent electrode whose surface was subjected to parallel treatment by rubbing, and this element was placed between two orthogonal polarizers. When an electric field was applied, changes in transmitted light intensity were observed due to the application of +5V. 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, and the viscosity estimated from the half-width of the polarization reversal current peak when a rectangular voltage was applied was determined as follows.

Comparative Example Composition B consisting of the following compounds is Sc*■SA: 56
．． 5°C, SA1: showed a phase transition temperature of 74.1°C.

Further, the response time, Ps, and viscosity of this composition B were determined as follows.

(Effects of the Invention) The present invention provides a novel liquid crystal compound, and by using the liquid crystal compound in combination with a ferroelectric liquid crystal material, a ferroelectric liquid crystal composition with improved responsiveness due to lower viscosity is provided. be done.

[Brief explanation of the drawing]

Figure 1 shows 5-heptyloxymethyl-2 obtained in Example 1.
1H-NMR spectrum of -(4-heptylphenyl)pyridine is shown.

Claims (2)

[Claims] Claims 1: The following general formula (I) [In the formula (I), R1 represents an alkyl group having 7 to 15 carbon atoms, and R2 represents an alkoxymethyl group having 6 to 15 carbon atoms. ] A phenylpyridine compound represented by [Claim 2] The following general formula (I) [In the formula (I), R1 represents an alkyl group having 7 to 15 carbon atoms, and R2 represents an alkoxymethyl group having 6 to 15 carbon atoms. ] At least one phenylpyridine compound represented by
A liquid crystal composition characterized by containing more than one type of liquid crystal composition.