JP2511746B2 - Liquid crystal compounds and compositions - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel liquid crystal compound useful as a component of a liquid crystal composition used for a liquid crystal display device and the like and a liquid crystal composition containing this liquid crystal compound. More specifically, the present invention provides a novel naphthalene-based liquid crystal compound exhibiting a chiral smectic C phase (hereinafter abbreviated as Sc * phase) and a liquid crystal composition containing the liquid crystal compound.

[0002]

2. Description of the Related Art Recently, a display system using a ferroelectric liquid crystal compound was reported by Mayer et al. According to this, a high-speed response and a memory effect 100 to 1000 times higher than that of a TN type can be obtained, so that a next-generation display can be obtained. It is expected as an element, and research and development are being actively pursued at present. The liquid crystal phase of the ferroelectric liquid crystal compound belongs to the tilt type chiral smectic phase, but practically, it is abbreviated as the chiral smectic C phase (hereinafter, referred to as Sc * phase), which has the lowest viscosity. ) Is most desirable. A large number of liquid crystal compounds exhibiting the Sc * phase have already been synthesized and studied, but the conditions for use as a ferroelectric display element are: (a) showing Sc * in a wide temperature range including room temperature, b) showing uniform orientation and having a large helical pitch,
(C) having an appropriate tilt angle, (d) having low viscosity, and the like. However, no liquid crystal compound exhibiting the Sc * phase that satisfies these conditions alone has been known, and efforts have been made to satisfy these conditions by mixing. In addition, the development of new liquid crystal compounds exhibiting the Sc * phase is also in progress. On the other hand, as a method for preparing a liquid crystal composition exhibiting a Sc * phase (hereinafter referred to as a Sc * liquid crystal composition), a chiral compound is added to a liquid crystal compound or composition exhibiting a non-chiral Sc phase that does not exhibit ferroelectricity. There is also a method of addition, and development of a liquid crystal compound exhibiting a Sc phase is underway. A racemate of a liquid crystal compound exhibiting the Sc * phase can also be used as the liquid crystal compound exhibiting the Sc phase. Conventionally, Sc phase or S
Phenylpyrimidine-based liquid crystal compounds represented by the following chemical formulas 6 and 7 are known as typical liquid crystal compounds exhibiting the c * phase.

[0003]

Embedded image

[0004]

[Chemical 7]

[0005]

However, since the Sc * liquid crystal composition using these phenylpyrimidine type liquid crystal compounds has poor orientation, zigzag defects are likely to occur when injected into a cell, and the contrast ratio is not increased. There's a problem.

[0006]

Means for Solving the Problems The present inventors have used a liquid crystal compound exhibiting an Sc * phase, which is used as a component of an Sc * liquid crystal composition having a better orientation than the above compounds, and a liquid crystal compound exhibiting a racemic Sc phase. As a result of intensive investigations, a new liquid crystal compound having a structure different from the conventional one was found, and the present invention was completed. That is, the present invention is represented by the following general formula

[0007]

[In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms, A represents a group selected from the following Chemical formulas 9 to 12,
NAP represents a 2,6-naphthylene group, n represents an integer of 0 to 9, * represents an asymmetric carbon atom, and R ² represents ^{2 to 2} carbon atoms.
And a liquid crystal composition containing at least one kind of the liquid crystal compound.

[0008]

[Chemical 9]

[0009]

[Chemical 10]

[0010]

[Chemical 11]

[0011]

[Chemical 12]

In the general formula (1), the number of carbon atoms represented by R ¹ is 1
Specific examples of the alkyl group of to 18 include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group,
n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group, etc. Is mentioned.

Of these, preferred ones have 3 to 10 carbon atoms.
14 alkyl groups. n is preferably an integer of 0-5. Specific examples of the alkyl group having 2 to 10 carbon atoms represented by R ² include ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n- Examples thereof include an octyl group, an n-nonyl group and an n-decyl group. Of these, preferred ones have 2 to 2 carbon atoms.
6 is an alkyl group. Specific examples of the liquid crystal compound of the present invention include compounds having groups shown in Tables 1 to 4.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

[0017]

[Table 4]

In Tables 1 to 4, each symbol represents the following group. _{ETY; C 2 H 5 - HEX} ; nC 6 H 13 - OC
_{T; nC 8 H 17 - NON} ; nC 9 H 19 - DEC; nC 10 H 21 - UN
D; nC ₁₁ H ₂₂ −

The liquid crystal compounds of the present invention exemplified in Table 1 above show the Sc * phase in the optically active form and the Sc phase in the case of the racemic form, all of which are useful as a component of the liquid crystal composition. The compound of the present invention can be synthesized, for example, through the steps shown in <I> to <IV>, wherein R ¹ , NAP and R ² are the same as those in the general formula (1). <I> When A is a group represented by Chemical formula 9

[0020]

[Chemical 13]

That is, 6-bromo-2-naphthol and the alcohol of the general formula (2) are condensed with a dehydration condensation agent (for example, diethyl azodiformate and triphenylphosphine), or 6- The compound of the general formula (4) can be obtained by reacting bromo-2-naphthol with the p-toluenesulfonic acid ester of alcohol represented by the general formula (3) in the presence of a base. Grignard obtained from the compound of general formula (4) and metallic magnesium
The compound of the general formula (6) can be obtained by reacting a phenol reagent with 2,5-dibromopyridine in the presence of a palladium catalyst. Compounds of general formula (6) and general formula (7)
The compound of the general formula (8) can be obtained by reacting 1-alkyne represented by the formula (1) in triethylamine in an inert gas atmosphere in the presence of a palladium catalyst. A compound of the general formula (1a), which is a compound of the present invention, can be obtained by hydrogenating the compound of the general formula (8) using a palladium carbon under a hydrogen atmosphere. <II> When A is a group represented by Chemical formula 10

[0022]

Embedded image

That is, 6-cyano-2-naphtho- obtained by reacting 6-bromo-2-naphthol with copper (I) cyanide.
The amidine salt can be obtained by reacting hydrogen chloride gas with hydrogen chloride in anhydrous ethanol and then with ammonia gas. The compound of general formula (10) can be obtained by reacting this amidine salt with acrolein represented by general formula (9) in ethanol in the presence of a base (for example, sodium ethoxide). General formula (10)
The compound of formula (2) is condensed with a dehydrating condensing agent (for example, diethyl azodiformate and triphenylphosphine) or the p of the alcohol of formula (3) is condensed. -The compound of the general formula (1b), which is the compound of the present invention, can be obtained by reacting toluenesulfonic acid ester in the presence of a base. In addition, some of the compounds of general formula (9), which are the starting materials for the above compound (1b), can be obtained as commercial products, and some of them can be synthesized through the following steps.

[0024]

[Chemical 15]

That is, the compound of the general formula (13) obtained by reacting the compound of the general formula (11) with a Grignard reagent prepared from metallic magnesium and ethyl orthoformate,
The compound of the general formula (9), which is a raw material of the compound of the present invention, can be obtained by acting a Vilsmeier reagent.

<III> When A is a group represented by Chemical formula 11

[0027]

[Chemical 16]

That is, by reacting the Grignard reagent of the general formula (5) with 1-bromo-3-fluoro-4-iodobenzene in the presence of a palladium catalyst, the general formula (1
The compound of 4) can be obtained. A compound of the general formula (1) is obtained by reacting a compound of the general formula (14) with a 1-alkyne represented by the general formula (7) in the presence of a palladium catalyst.
The compound of 5) can be obtained. The compound of the general formula (15), which is the compound of the present invention, can be obtained by hydrogenating the compound of the general formula (15) using palladium carbon. <IV> When A is a group represented by Chemical formula 12,

[0029]

[Chemical 17]

That is, the compound of the general formula (16) can be obtained by reacting the Grignard reagent of the general formula (5) with 4-benzyloxy-2,3-difluoroiodobenzene in the presence of a palladium catalyst. . General formula (1
The compound of general formula (17) can be obtained by hydrogenolysis of the compound of 6) using palladium carbon. By reacting the compound of the general formula (17) with trifluoromethanesulfonic anhydride, the compound of the general formula (18)
Can be obtained. The compound of general formula (19) can be obtained by reacting the compound of general formula (18) with 1-alkyne represented by general formula (7) using a palladium catalyst in an inert gas atmosphere. By hydrogenating the compound of the general formula (19) using palladium carbon, the compound of the general formula (1d)
Can be obtained. In addition, the above compound (1d)
4-Benzyloxy-2,3-difluoroiodobenzene, which is the starting material of, can be synthesized through the following steps.

[0031]

[Chemical 18]

That is, 2,3-difluorophenol is iodinated with sodium hypochlorite and sodium iodide, and then benzyl chloride is added in the presence of a base.
By tellurization, 4-benzyloxy-2,3-difluoroiodobenzene can be obtained.

The liquid crystal compound is generally used as a component of a liquid crystal composition composed of two or more kinds of components, and the liquid crystal compound of the present invention can also be used as a component of the liquid crystal composition. The liquid crystal composition of the present invention comprises a mixture of a plurality of compounds and contains at least one liquid crystal compound of the present invention. Examples of the composition of the present invention include the liquid crystal composition [1] of the present invention exhibiting the Sc phase and the liquid crystal composition [2] of the present invention exhibiting the Sc * phase. In the liquid crystal composition [1] of the present invention, at least one liquid crystal compound exhibiting the Sc phase which is the racemic compound of the present invention is an essential component, and as an optional component, a liquid crystal compound (2-4′-) exhibiting another Sc phase. Alkyloxyphenyl-5-alkylpyrimidines, 2-4'-alkylphenyl-5-alkyloxypyrimidines, 2-4'-
Alkyloxyoxyphenyl-5-alkyloxypyrimidines, 2-p-alkyloxycarbonylphenyl-5-
Alkylpyrimidine, 2-4'-alkyloxy-3'-fluorophenyl-5-alkylpyrimidine, 2-4'-alkyloxy-2 ', 3'-difluorophenyl-5-alkylpyrimidine, 2-4'-alkyl Oxyphenyl-5-
Alkyl pyridine, 2-4′-alkyloxy-3′-fluorophenyl-5-alkyl pyridine, etc.), a mixture containing a compound selected from a smectic liquid crystal compound not exhibiting a Sc phase and a liquid crystal compound exhibiting a nematic phase.
In the liquid crystal composition [1] of the present invention, the content of one or more liquid crystal compounds of the present invention is usually 5 to 100% by weight. In the liquid crystal composition [2] of the present invention, at least one kind of liquid crystal compound showing Sc * of the present invention is an essential component, and as an optional component, the liquid crystal composition [1] of the present invention and another liquid crystal compound showing a Sc phase. (2-4'-alkyloxyphenyl-5-alkylpyrimidine, 2-4'-alkylphenyl-5-alkyloxypyrimidine, 2-4'-alkyloxyoxyphenyl-5-
Alkyloxypyrimidine, 2-p-alkyloxycarbonylphenyl-5-alkylpyrimidine, 2-4'-alkyloxy-3'-fluorophenyl-5-alkylpyrimidine, 2-4'-alkyloxy-2 ', 3' -Difluorophenyl-5-alkylpyrimidine, 2-4'-alkyloxyphenyl-5-alkylpyridine, 2-4'-alkyloxy-3'-fluorophenyl-5-alkylpyridine, etc.), liquid crystal exhibiting Sc * phase Compounds (optically active 4-alkyloxy-4'-biphenylcarboxylic acid-p '-(2-methylbutyloxycarbonyl) phenyl ester, optically active 4-n-alkyloxy-4'-biphenylcarboxylic acid-
2-methylbutyl ester, etc.), chiral compounds (JP-A-63-99032, JP-A-63-190843, JP-A-2-138274, JP-A-2-256673, JP-A-2-262579, JP-A-2-286673, JP-A-3
-27374 etc.), a smectic liquid crystal compound which does not exhibit an Sc phase, a liquid crystal compound which exhibits a nematic phase, and a compound selected from dichroic dyes (anthraquinone dyes, azo dyes, etc.). In the liquid crystal composition [2] of the present invention, the content of one or more liquid crystal compounds of the present invention is usually 5 to 99% by weight.

A liquid crystal composition exhibiting ferroelectricity causes an optical switching phenomenon when a voltage is applied, and a liquid crystal display element having a fast response can be manufactured by utilizing this phenomenon [see, for example, JP-A-56-1].
07216, JP 59-118744 A, NA Clark, ST-Ragawall (S.
T.Lagerwall); Applied Physics Letter (App
lied Physics Letter) 36 , 899 (1980), etc.].

The liquid crystal composition of the present invention showing the Sc * phase [2]
Can be used as an optical switching element (liquid crystal display element) by vacuum-sealing in a liquid crystal cell having a cell interval of 0.5 to 10 μm, preferably 0.5 to 3 μm and installing polarizers on both sides. The liquid crystal cell can be manufactured by providing a transparent electrode and bonding two glass substrates whose surfaces are oriented with a spacer interposed therebetween. Examples of the spacer include alumina beads, glass fiber, and polyimide film. As the alignment treatment method, a normal alignment treatment, for example, a polyimide film, a rubbing treatment, or a SiO oblique vapor deposition can be applied.

[0036]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Example 1 No. 1 in Table 1 Preparation of Compound 1 6-Bromo-2-naphthol in 400 ml of dry ethanol
25.0 g and potassium hydroxide 7.5 g were added and stirred until the solution became uniform. Then optically active p-toluenesulfonic acid-
2-Methylbutyl ester (27.4 g) was added and the mixture was heated under reflux for 20 hours. After the reaction was completed, ethanol was removed and water was added. The resulting solid was filtered and dried, and then recrystallized from methanol to obtain 24.6 g of optically active 6-bromo-2- (2'-methylbutyloxy) naphthalene. Grigna prepared from 5.0 g of 6-bromo-2- (2'-methylbutyloxy) naphthalene obtained in 3.2 and 3.2 g of 1,2-dibromoethane
2,5-dibromopyridine (4.9 g) was added to a diethyl ether solution of the reagent and nitrogen substitution was performed. After cooling to 10 ° C or lower with an ice water bath, 100 mg of dichloro {1,4-bis (diphenylphosphino) butane} palladium (II) was added and the mixture was stirred for 1 hour as it was. After removing the ice water bath and stirring for further 2 hours, water was added while cooling in the ice water bath. After adding toluene, the organic layer was washed with water and then the solvent was removed. The obtained solid was recrystallized with ethanol to obtain 3.4 g of the compound (a) represented by the following chemical formula 19.

[0037]

[Chemical 19]

1.7 g of the compound (a) obtained in 1 and 1-decyne
1.3 g of triethylamine in 70 ml of copper (I) iodide 5 mg, dichlorobistriphenylphosphine palladium (II) 20
mg and triphenylphosphine 40 mg, and heated under reflux for 6 hours under a nitrogen atmosphere. After completion of the reaction, the temperature was returned to room temperature to remove triethylamine. After extracting the product with toluene, the toluene layer was washed with 1N hydrochloric acid and washed with water, and then treated with a silica gel column. After removing toluene, 150 ml of ethanol and 200 mg of 5% palladium carbon were added to the obtained solid, and hydrogenation was performed at a reflux temperature. After confirming that the absorption of hydrogen disappeared, the catalyst was removed by filtration and cooled to room temperature. The obtained crystal was recrystallized twice with ethanol to give a white crystal of the compound of the present invention, No. 1 in Table 1. 1.2 g of compound 1 was obtained. The structure of the compound is NMR (nuclear magnetic resonance spectrum analysis), MS
It was confirmed by (mass spectrometry), IR (infrared absorption spectrum analysis) and elemental analysis. IR (cm ^-1 ) 2922.0 2854.0 1630.0 1605.0 1493.0 1468.0 1390.0 1255.0 1212.0 1033.0 816.0 470.0 NMR (ppm) 0.88 (t, 3H) 0.99 (t, 3H) 1.07 (d, 3H) 1.18 ~ 1.43 (m, 15H) 1.55 ~ 1.70 (m, 3H) 1.88 ~ 2.01 (m, 1H) 2.64 (t, 2H) 3.83 ~ 4.00 (m, 2H) 7.13 ~ 7.20 (m, 2H) 7.55 (dd, 1H) 7.72 ~ 7.86 (m, 3H) 8.08 (dd, 1H) 8.38 (d, 1H) 8.53 (d, 1H) Elemental analysis value Theoretical value (%) Actual value (%) C: 83.53 C: 83.41 H: 9.51 H: 9.73 N: 3.25 N: 3.39 Implemented Table 5 shows the phase transition temperatures of the compound obtained in Example 1.

[0039]

[Table 5] Example Phase transition temperature (° C) -----------------------------. Cry Sc * S _A I −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 1 ・ 74.0 ・ 81.4 ・ 88.3 ・−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Each symbol in Table 5 has the following meaning. Cry; Crystal phase Sc *; Chiral smectic C phase S _A ; Smectic A phase Iso; Isotropic liquid phase.

[0041]

By using the liquid crystal compound of the present invention as a component of the Sc * liquid crystal composition, the orientation of this composition can be improved and the contrast ratio can be increased.
Further, the liquid crystal compound of the present invention is a compound capable of extending the temperature range of the Sc * phase by being used as a component of the Sc * liquid crystal composition because it does not exhibit other smectic phases in the low temperature range. Therefore, the compounds and compositions of the present invention are useful as liquid crystal materials used in liquid crystal display devices.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuro Yanagi 1-11 Ichibashi-honcho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd. Examiner Michie Hirayama

Claims (2)

(57) [Claims] 1. The following general formula: [In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms, and A 1
Represents a group selected from the following chemical formulas 2 to 5, NAP represents a 2,6-naphthylene group, n represents an integer of 0 to 9, * represents an asymmetric carbon atom, and R ² represents the number of carbon atoms. Represents an alkyl group of 2 to 10]. Embedded image Embedded image Embedded image Embedded image 2. A liquid crystal composition comprising a mixture of a plurality of compounds and containing at least one liquid crystal compound according to claim 1.