JPH05208941A - Nitrogen-containing troponoid liquid crystal - Google Patents

Abstract

PURPOSE:To obtain the subject nitrogen-containing troponoid compound, useful as a liquid crystal compound, having characteristics excellent as a liquid crystal and capable of realizing a chiral smectic C phase or a nonchiral smectic C phase. CONSTITUTION:The objective compound of formula I (R<1> and R<2> are 1-18C alkyl), e.g. 5-dodecyloxy-2-(4-dodecylaminobenzoyloxy) tropone. This compound is obtained by reacting a 5-hydroxytropone of formula III with an alkyl bromide of the formula R<1>Br, providing a 5-alkoxytropone of formula IV and then reacting the resultant 5-alkoxytropone of formula IV with a 4-alkylaminobenzoic acid chloride of formula V.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel compound useful as a liquid crystal substance in the field of liquid crystal display devices and liquid crystal light switching devices, and more particularly to nitrogen-containing troponoid compounds.
Further, the present invention relates to a liquid crystal composition and a liquid crystal device using the compound.

[0002]

2. Description of the Related Art A liquid crystal display device is widely used in many fields because it has a characteristic that it can be driven with low voltage and low power. For example, a display device in a small device such as a calculator and a word processor, a display device in a dashboard such as an automobile or an airplane is a typical example of use, but due to the improvement in performance, its application range is also applied to fields such as a liquid crystal television. It has been expanded.

As described above, the liquid crystal display element is undergoing remarkable development, and various proposals have been made regarding the device configuration including the operating principle.

The characteristics of the liquid crystal display device largely depend on the characteristics of the liquid crystal material used, and in order to improve the characteristics of the liquid crystal display device, it is important to use a liquid crystal material that conforms to the operating principle of each display device. is there. Therefore, research on liquid crystal substances having desirable characteristics has been actively conducted. New liquid crystal materials also have the potential to provide new operating principles for liquid crystal display devices.

However, compared to other electronic display devices such as LEDs, liquid crystal display devices have the drawback that the response speed is significantly slower. In order to overcome this drawback, current liquid crystal technology is concerned with realizing a reduction in response time by phase conversion using a chiral smectic C phase generated by a layered arrangement of chiral molecules.

On the other hand, troponoids, that is, tropone derivatives are typical compounds of non-benzene aromatic compounds, and many compounds have already been synthesized as interesting research targets. However, it is extremely rare that the troponoid compound is used for industrially useful applications.

The present inventors have been engaged in the synthesis and physical property research of troponoid compounds for many years.
It was found that the troponoid compound represented by the general formula (II) shown in (3) has excellent properties as a liquid crystal, and a patent application has already been filed for this (Japanese Patent Application No. 2-239338).
However, this troponoid compound is not always satisfactory in liquid crystal properties, especially in the phase transition temperature.

[0008]

[Chemical 2]

However, R ¹ and R in the general formula (I)
² represents the following respectively.

R ^{1 is} an alkyl group having 6 to 18 carbon atoms, and R ² is an alkyl group having 1 to 12 carbon atoms.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object thereof is a compound (II) which is useful as a liquid crystal compound and which is disclosed in the previous application.
Another object of the present invention is to provide a nitrogen-containing troponoid compound having excellent properties as a liquid crystal.

[0012] A second object of the present invention is to provide a liquid crystal composition which can be used as a smectic liquid crystal, particularly a novel liquid crystal composition which can realize a chiral smectic C phase or a non-chiral smectic C phase.

A third object of the present invention is to provide a liquid crystal display device using a novel liquid crystal composition in order to improve the response speed.

[0014]

The first object of the present invention is to:
This is achieved by the compound represented by the general formula (I) shown below.

[0015]

[Chemical 3]

However, R ¹ and R in the general formula (I)
² represents the following respectively.

R ^{1 is} an alkyl group having 1 to 18 carbon atoms, R ^{2 is} an alkyl group having 1 to 18 carbon atoms, and the second object of the present invention is selected from the group of compounds represented by the above general formula (I). And a liquid crystal composition containing at least one compound.

The third object of the present invention is achieved by a liquid crystal display device comprising a liquid crystal cell filled with the above liquid crystal composition.

The details of the present invention will be described below.

<Compound (I)> The present invention is based on the discovery that the nitrogen-containing troponoid compound of the above-mentioned general formula (I) exhibits a liquid crystal state, and in particular, substantially exhibits only a smectic C phase. ..

In the general formula (I), R ¹ has ¹ to 10 carbon atoms.
There is no particular limitation as long as it is an alkyl group having 18 carbon atoms, but an alkyl group having 6 to 18 carbon atoms is preferable. R ¹ may contain one or more branched methyl groups or branched ethyl groups, and in this case, the alkyl group may be an optically active group.

R ² is not particularly limited as long as it is an alkyl group having 1 to 18 carbon atoms, but preferably 4 to 1 carbon atoms.
2 is an alkyl group. Further, R ² may contain one or more branched methyl groups or branched ethyl groups, and in this case, the alkyl group may be an optically active group.

Specific examples of the optically active group of R ¹ and R ² include the following.

1-methylpropyl, 1-methylbutyl,
1-methylpentyl, 1-methylhexyl, 1-methylheptyl, 1-methyloctyl, 1-methylnonyl, 1
-Methyldecyl, 1-methylundecyl, 1-methyldodecyl, 2-methylbutyl, 3-methylpentyl, 4-
Methylhexyl, 5-methylheptyl, 6-methyloctyl, 7-methylnonyl, 8-methyldecyl and representative examples of the compounds according to the present invention are shown in Table 1 below.

<Production of Compound (I)> Compound (I) is
For example, it can be suitably produced according to the reaction route shown in Chemical Formula 4 below.

[0026]

[Chemical 4]

That is, first, 5-hydroxytropolone (II
Alkyl bromide is allowed to act on I) to give 5-alkoxytropolone (IV). Then, 5-alkoxy-2- (4-alkylaminobenzoyloxy) tropone (I) can be obtained by reacting this with 4-alkylaminobenzoic acid chloride.

<Liquid Crystal Composition> The liquid crystal composition of the present invention can be constituted so as to contain only a plurality of compounds represented by the formula (I). In addition to one or more compounds represented by formula (I), one or more other compounds may be contained.

In the case of a liquid crystal composition consisting only of a plurality of compounds represented by the formula (I), by mixing a plurality of compounds having a desired liquid crystal phase among the compounds of the formula (I), It is possible to obtain a liquid crystal composition exhibiting a desired liquid crystal phase over a wide temperature range.

When one or more compounds represented by formula (I) and one or more other compounds are contained,
The compound of formula (I), which may be mixed, is not particularly limited,
Various ones can be used. Formula (I) at this time
The ratio of the compound of is preferably 0.5% to 80%, more preferably within 50%.

<Liquid Crystal Display Device> The liquid crystal display device according to the present invention is characterized by using the above liquid crystal composition. Therefore, the specific configuration of the device is not particularly limited, and the same liquid crystal cell structure as the conventional one can be used. Moreover, the device configuration currently used, such as a simple matrix type or an active matrix type, can be used as it is.

[0032]

The action and effect of the present invention The troponoid compound (I) of the present invention exhibits only a smectic C phase as a liquid crystal phase. This is probably because the molecules of compound (I) are arranged in a tilted manner as shown in FIG. Moreover, it is considered that the [1,9] sigmatropy of the compound (I) and the intermolecular hydrogen bond between the NH group and the C═O group contribute to such a molecular arrangement.

The smectic C liquid crystal phase can be suitably used for a new display system using a ferroelectric liquid crystal which is being actively researched at present. This new display method is expected to significantly improve the response speed (Clar
k et al., Applied Phys.lett., 36,899 (1980)). In this display method, a chiral smectic phase such as a chiral smectic C phase (hereinafter abbreviated as Sc ^* phase) exhibiting ferroelectricity is used. In addition, chiral smectic F, G,
The liquid crystal phases such as H and I also show the same ferroelectricity as the Sc ^* phase.

The ferroelectric liquid crystal composition can be formed by using only the ferroelectric liquid crystal compound. Other than that, non-chiral smectic C, F, G,
Mixing one or more ferroelectric liquid crystal compounds or non-liquid crystal optically active compounds, using as a basic substance a compound or composition exhibiting a tilted smectic phase such as H or I (hereinafter abbreviated as a phase such as Sc). Thus, a method of forming a composition exhibiting a ferroelectric liquid crystal phase as a whole can be used. As these basic substances, a compound group of various systems showing a non-chiral smectic liquid crystal phase such as Sc is used.

As described above, the compound (I) of the present invention exhibits the Sc phase in a temperature range relatively higher than room temperature. Therefore, by using a plurality of kinds of compound (I) in combination, the ferroelectric The basic substance of the organic liquid crystal composition can be constituted. A ferroelectric liquid crystal composition can be obtained by adding an optically active compound, preferably an optically active liquid crystal compound, and more preferably one or more ferroelectric liquid crystal compounds to the basic substance thus constituted.

Next, the effect of the present invention will be described in more detail in comparison with the troponoid compound (II) according to the prior invention.

The following No. 1-No.
Compound (I) of No. 7 was prepared and its phase transition temperature was measured. Further, the compound (II) of the prior invention having the same substituents R ¹ and R ² as the above was synthesized according to the method described in the examples of the prior application, and the phase transition temperature thereof was measured. The results were as follows.

Table 1 Substituents Phase transition temperature (° C.) Compound (I) Compound (II) No. R ¹ R ² Cr.Sc.I Cr.Sc.Sa.I 1 n-C ₆ H ₁₃ n-C ₁₂ H ₂₅ 115 (90) 102 2 n-C ₈ H ₁₇ n-C ₁₂ H ₂₅ 108 (100) 100 3 n-C ₁₂ H ₂₅ n-C ₁₂ H ₂₅ 108 (108) 96 (95) 4 n-C ₁₄ H ₂₉ n-C ₁₂ H ₂₅ 109 115 5 n-C ₁₈ H ₃₇ n-C ₄ H ₉ 112 97 (88 95) 6 n-C ₁₈ H ₃₇ n-C ₁₂ H ₂₅ 108 111 98 105 7 n- C ₁₈ H ₃₇ n-C ₁₈ H ₃₇ 111 (111) where Cr is a crystalline phase, Sc is a smectic C phase, Sa is a smectic A phase, and I is an isotropic liquid phase. Also,
() Indicates that the phase is a phase that appears monotropically.

As is clear from the above results, the upper limit temperature of the liquid crystal temperature range of the compound (I) of the present invention is about 10 degrees higher than that of the corresponding compound (II) of the prior application.
Furthermore, No. 1 and No. 2, the compound (I) of the present invention showed a liquid crystal phase, whereas the compound (II) of the prior invention did not show liquid crystallinity. As a result, the compound (I) of the present invention is the compound of the prior application (II) for the following reason.
As a liquid crystal compound.

That is, as described above, the composition exhibiting a phase such as Sc, which is the basic substance of the ferroelectric liquid crystal composition, is required to exhibit the phase such as Sc in a wide temperature range including room temperature. .. In this respect, the upper limit of the liquid crystal temperature region in the compound (I) of the present invention is higher than that of the compound (II) of the prior invention, so that the liquid crystal composition can be prepared by adding the compound (I) of the present invention. The upper limit temperature of Sc can be increased.
In other words, the ferroelectric liquid crystal composition using the compound (I) of the present invention can exhibit ferroelectricity in a temperature range over a higher temperature.

[0041]

EXAMPLES The compounds of the present invention will be described in more detail below with reference to examples.

Example 1 Preparation of Compound (I) shown in Table 3, No. 3, namely 5-dodecylamino-2- (4-dodecylaminobenzoyloxy) tropone; (1) Preparation of 5-dodecyloxytropolone Synthesis Sodium hydride (oil, 55%) 300m under ice cooling
Hexamethylphosphoramide (10 mL) was added to g. Subsequently, 750 mg of 5-hydroxytropolone was added and stirred. Furthermore, after 15 minutes, 1.6 mL of 1-bromododecane was added,
The mixture was stirred at room temperature for 12 hours. This was poured into 50 mL of 2N hydrochloric acid, extracted with ethyl acetate, the organic layer was washed with water, dried and then concentrated. The residue was recrystallized from ethyl acetate to give 5-dodecyloxytropolone.

(2) Synthesis of title compound To a solution of 183 mg of 4-dodecylaminobenzoic acid (melting point; 125 ° C) dissolved in 5 mL of benzene, 2 mL of thionyl chloride was added. After heating under reflux for 5 hours, benzene and excess thionyl chloride were distilled off under reduced pressure. 3 mL of pyridine in the residue
And 5-dodecyloxytropolone synthesized in (1) 1
53 mg and a catalytic amount of 4-dimethylaminopyridine were added, and the mixture was stirred at room temperature for 12 hours. The reaction solution was poured into an aqueous solution of potassium hydrogen sulfate and extracted with chloroform, the organic layer was dried using magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified using silica gel chromatography to give the title compound, 5-dodecyloxy-2-.
(4-dodecylaminobenzoyloxy) tropone 193
mg was obtained (yield 65%).

The spectral data and elemental analysis data of the product are shown below. The phase transition temperature of the product is shown in Table 1.

¹ H-NMR (CDCl ₃ ; δ (ppm)) 0.88 (6H, t, J = 6.6Hz), 1.15-1.60 (36H, m), 1.63
(2H, quint, J = 7.3Hz), 1.80 (2H, quint, J = 6.6Hz), 3.
16 (2H, t, J = 7.3Hz), 3.91 (2H, t, J = 6.6Hz), 6.21 (1
H, br.d, J = 12.1Hz), 6.58 (2H, dm, J = 8.8Hz), 7.10 (1
H, br.d, J = 12.1Hz), 7.22 (2H, d, J = 12.1Hz), 7.98 (2
H, dm, J = 8.8 Hz), ¹³ C-NMR (CDCl ₃ ; ppm) 14.1 (2C), 22.7 (2C), 25.9, 27.1, 28.8, 29.3 (3
C), 29.4, 29.5, 29.6 (7C), 31.9 (2C), 43.6, 68.
8, 105.8, 111.7 (2C), 116.9, 128.7, 132.6 (2
C), 134.0, 140.1, 152.1, 152.4, 162.8, 164.
6, 178.5, IR (KBr; cm ^-1 ) 3320, 2930, 2860, 1730, 1650, 1570, 1525, 1245, 11
80, 1160, 1080 MS; m / z (%) 593 (1, M ⁺ ), 306 (34), 288 (59), 138 (bas
e) Elemental analysis C H N Found: 76.88 9.89 2.15 Calculated _{(C 38 H 59 NO 4)} ; 76.85 10.01 2.36.

Examples 2 to 7 According to the method of Example 1, Nos. 1, 2 and
Compounds (I) of 4,5,6,7 were prepared. The phase transition temperatures of these compounds were as shown in Table 1.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state in which a troponoid compound (I) of the present invention is tilted and aligned when exhibiting a smectic C liquid crystal phase.

Claims (4)

[Claims] 1. A compound represented by the following general formula (I): [Chemical 1] However, R ¹ and R ² in the general formula (I) respectively represent the following. R ¹ : an alkyl group having 1 to 18 carbon atoms, R ² : an alkyl group having 1 to 18 carbon atoms 2. A liquid crystal composition comprising a plurality of compounds selected from the group of compounds according to claim 1. 3. A liquid crystal composition containing at least one compound selected from the group of compounds according to claim 1. 4. A liquid crystal display device comprising a liquid crystal cell filled with the liquid crystal composition according to claim 2.