JP3054177B2 - Pyridine liquid crystal compounds - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel pyridine-based liquid crystal compound useful for a display device.

[Prior art] Currently, TN (twisted nematic) is used as a liquid crystal display device.
The type display method is most widely used. This TN liquid crystal display has many advantages such as low driving voltage and low power consumption. However, they are inferior to light emitting devices (cathode tubes, electroluminescence, plasma displays, etc.) in response speed. A new TN display device with a twist angle of 180 to 270 ° has been developed, but the response speed is still inferior. As described above, various efforts have been made for improvement, but a TN type display element having a high response speed has not been realized. However, in a new display method using a ferroelectric liquid crystal, which has been actively studied recently, there is a possibility that the response speed can be remarkably improved (NAClark et al .; Applied Phys.lett., 36, 899 (198).
0)). This method uses a chiral smectic phase such as a chiral smectic C phase exhibiting ferroelectricity. It is known that not only the chiral Sc phase but also the phases such as chiral smectic F, G, H and I exhibit ferroelectricity.

Many characteristics are required for ferroelectric liquid crystal materials used in ferroelectric liquid crystal display devices actually used, but at present, a single compound cannot satisfy such characteristics, It is necessary to use a ferroelectric liquid crystal composition obtained by mixing a liquid crystal compound or a non-liquid crystal compound.

Further, not only a ferroelectric liquid crystal composition consisting of a ferroelectric liquid crystal compound alone, but also a compound exhibiting a non-chiral smectic C, F, G, H, I, etc. It has been reported that a composition can be used as a basic substance, and one or more compounds exhibiting a ferroelectric liquid crystal phase can be mixed therewith to form a ferroelectric liquid crystal composition as a whole. Furthermore, a compound or composition exhibiting a phase such as smectic C is used as a basic substance, and one or more compounds that are optically active but do not exhibit a ferroelectric liquid crystal phase are mixed to form a ferroelectric liquid crystal composition as a whole. (Mol. Cryst. Liq. Cryst., 89, 327 (1982)).

Taken together, it can be seen that a ferroelectric liquid crystal composition can be constructed by mixing one or more optically active compounds with a basic substance regardless of whether or not it exhibits a ferroelectric liquid crystal phase.

As these basic substances, various compounds exhibiting a non-chiral smectic liquid crystal phase such as smectic C are used, but practically a liquid crystal compound or a mixture exhibiting a smectic C phase in a wide temperature range including room temperature is desirable. As components of these smectic C liquid crystal mixtures,
And liquid crystal compounds such as phenylbenzoate, biphenyl, phenylpyridine and 5-alkyl-2- (4-alkoxyphenyl) pyrimidine.

[Problems to be Solved by the Invention] However, it is determined whether or not a chiral smectic C liquid crystal material obtained by adding an optically active compound thereto exhibits excellent performance in a liquid crystal display utilizing ferroelectricity. , The final evaluation has not yet been obtained. This is because liquid crystal displays utilizing ferroelectricity have not been technically completed. Therefore, at present, it is necessary to carry out various tests on a new material for a smectic C liquid crystal composition.

[Means for Solving the Problems] The present inventors have conducted intensive studies on a novel liquid crystal compound useful for the smectic C liquid crystal composition, which is suitable for use as described above, and as a result, the present invention has been achieved. did. That is, the present invention relates to the general formula Wherein R and R ′ are an alkyl group having 1 to 18 carbon atoms;
X ₁ and X ₂ are a single bond (direct bond), -O-, -S- or-
C≡C—, Y is —C≡C—, and A is a 1,4-phenylene group or a 4,4′-biphenylene group which may be substituted with a fluorine atom or a chlorine atom (in these groups, Is one or two CH groups which may be replaced by N) or a 2,6-naphthylene group (where A
But In this case, _one of X ₁ and X ₂ is always -C≡C-)].

In the general formula (1), examples of the alkyl group having 1 to 18 carbon atoms for R and R ′ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group,
n-heptyl group, n-octyl group, n-nonyl group, n-
Decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl and the like.

Of these, an alkyl group having 3 to 14 carbon atoms is preferable.

A is preferably substituted by a fluorine atom,
4-phenylene group, 4,4'-biphenylene group or 2,6-
It is a naphthylene group.

Examples of a group in which one or two CH groups present in a 1,4-phenylene group or a 4,4'-biphenylene group are replaced by N include: And so on.

Specific examples of the compound represented by the general formula (1) include compounds having a group shown in Table 1.

In Table 1, each symbol represents the following groups.

BUT; nC ₄ H ₉ -PEN; nC ₅ H ₁₁ -HEX; nC ₆ H ₁₃ -HEP; nC ₇ H ₁₅ -OCT; nC ₈ H ₁₇ -NON; nC ₉ H ₁₉ -DEC; nC ₁₀ H ₂₁ -UND nC ₁₁ H ₂₃ -DOD; nC ₁₂ H ₂₅ -TED; nC ₁₄ H ₂₉ -NAPHTHIL; 2,6-naphthylene group-; a compound represented by the general formula (1) representing a single bond can be prepared, for example, by the following process. Can be synthesized through (Where R, X ₁ , X ₂ , A and R ′ are the same as those in the general formula (1)) (1) When X ₁ is a single bond and Y is —C≡C— That is, the compound of the present invention is obtained by reacting the compound of the general formula (2) with the compound of the general formula (3) in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst. The compound of 1a) can be obtained.

Or That is, the compound of the general formula (4) is reacted with a compound of the general formula (2), 3-methyl-1-butyn-3-ol and triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst. After the compound is formed, powdered sodium hydroxide is allowed to act in anhydrous toluene to obtain a compound of the general formula (5)
Can be obtained. By reacting the compound of the general formula (5) and the compound of the general formula (6) in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst, the compound of the general formula (1)
The compound of a) can be obtained.

The compounds of the general formulas (2) and (5) can be synthesized, for example, through the following steps.

That is, the compound of the general formula (8) can be obtained by hydrogenating the compound of the general formula (7) using platinum dioxide in a hydrogen atmosphere. After diazotizing the compound of the general formula (8), the compound of the general formula (9) can be obtained by reacting the compound with an alkali metal iodide. General formula (9)
The compound of the general formula (11) can be obtained by reacting the compound of the general formula (10) with a compound of the general formula (10) in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst. The compound of the general formula (2), which is a raw material of the compound of the present invention, can be obtained by hydrogenating the compound of the general formula (11) under a hydrogen atmosphere using platinum dioxide. The compound of the general formula (2) is converted to 3-methyl-1
-Butyn-3-ol is reacted with triethylamine in an inert gas atmosphere using a zero-valent or divalent palladium catalyst to give a compound of the general formula (12), and then powdered sodium hydroxide in anhydrous toluene. To give a compound of the general formula (9), which is a raw material of the compound of the present invention.

The compounds of the general formulas (3) and (6) can be synthesized, for example, through the following steps.

X ₂ is -O-, A is Or 2,6-naphthylene group That is, the compound of the general formula (6a), which is a raw material of the compound of the present invention, can be obtained by alkylating the compound of the general formula (13) with an alkylating agent (for example, an alkyl halide). The compound of the general formula (6a) is converted to 3-methyl-
1-butyn-3-ol is reacted with triethylamine in an inert gas atmosphere using a zero-valent or divalent palladium catalyst to give a compound of the general formula (14), and then powdered in anhydrous toluene. By reacting sodium, a compound of the general formula (3a), which is a raw material of the compound of the present invention, can be obtained.

X ₂ is -O-, A is in the case of That is, the compound of the general formula (17) can be obtained by reacting the compound of the general formula (16) obtained by esterifying the compound of the general formula (15) with benzoyl chloride with phenylboric acid in the presence of a palladium catalyst. A compound of the general formula (17) is converted into a halogenating agent (for example, periodic acid +
After halogenation with iodine), the compound is hydrolyzed with an alkali (eg, sodium hydroxide) and isolated and purified to give the compound of the general formula (19). The compound of the general formula (6b), which is a raw material of the compound of the present invention, is obtained by reacting the compound of the general formula (19) with an alkali metal hydroxide and then alkylating the compound with an alkylating agent (eg, an alkyl halide). Can be obtained. General formula (6b)
Is reacted with trimethyl-1-butyn-3-ol in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst to give a compound of the general formula (21). By reacting powdered sodium hydroxide in toluene, the compound of the general formula (3b), which is a raw material of the compound of the present invention, can be obtained.

X ₂ is A is a single bond in the case of That is, the compound of the general formula (6c), which is a raw material of the compound of the present invention, can be obtained by diazotizing the compound of the general formula (22) and reacting the compound with a halide of an alkali metal. Compound of general formula (6c) and 3-methyl-1-
The compound of general formula (23) can be obtained by reacting butyn-3-ol in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst. The compound of the general formula (3c), which is a raw material of the compound of the present invention, can be obtained by reacting the compound of the general formula (23) with sodium hydroxide powder in anhydrous toluene.

(2) When X ₁ is -O- and Y is -C≡C- That is, the compound of the general formula (25) is obtained by reacting the compound of the general formula (24) and the compound of the general formula (3) in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst. I can do it. Reacting the compound of the general formula (25) with an alkali metal salt of an alcohol in anhydrous dimethylformamide or anhydrous dimethylsulfoxide in the presence of copper (I) iodide to obtain a compound of the general formula (1b) which is a compound of the present invention. Can be obtained.

(3) When X ₁ and Y are -C≡C- That is, the compound of the present invention is obtained by reacting a compound of the general formula (25) with a 1-alkyne represented by the general formula (26) in triethylamine under an inert gas atmosphere using a zero-valent or divalent palladium catalyst. The compound of the general formula (1c) can be obtained.

The liquid crystal is generally used as a liquid crystal composition composed of two or more 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 includes a smectic liquid crystal, for example, a smectic liquid crystal having no optically active site [2-p-alkyloxyphenyl-5-alkylpyrimidine, 2-p-alkylphenyl-5-alkyloxypyrimidine, 2-p-alkanoyl. Oxyphenyl-5-alkylpyrimidine, 2-p-alkyloxycarbonylphenyl-5-alkylpyrimidine, 2
-P-alkylphenyl-5-p-alkyloxyphenylpyrimidine, 2-p-alkyloxy-m-fluorophenyl-5-alkylpyrimidine, 2-p-alkyloxyphenyl-5- (trans-4-alkylscrohexyl ) Pyrimidine, 2-p-alkyloxyphenyl-5-alkylpyridine, 2-p-alkyloxy-
m-fluorophenyl-5-alkylpyridine, 2-p
-(P'-alkylphenyl) phenyl-5-alkylpyrimidine, 2-p-alkylphenyl-5-p-alkylphenylpyrimidine, p-alkyloxyphenyl-5-alkylpicolinate, 2-p-alkyloxyphenyl- 5-alkyloxypyrazine, 2-p-alkylphenyl-5-alkylpyrimidine, 2-p-alkyloxyphenyl-5-alkyloxypyrimidine,
2-p-alkylphenyl-5-alkyloxypyrimidine, 4-alkyloxy-4'-biphenylcarboxylic acid-p '-(alkyloxycarbonyl) phenyl ester, 4-alkyloxy-4'-biphenylcarboxylic acid-alkyl ester And / or ferroelectric liquid crystal [optically active 4-alkyloxy-4'-biphenylcarboxylic acid-p '-(2-methylbutyloxycarbonyl) phenyl ester, optically active 4-n-alkyloxy-4'- Biphenylcarboxylic acid-2-methylbutyl ester, optically active p-alkyloxybenzylidene-
p'-Amino-2-chloropropylcinnamate, optically active p-alkyloxybenzylidene-p'-amino-
2-methylbutyl cinnamate etc.] and / or ordinary chiral smectic liquid crystal [optically active 4- (p-alkyloxybiphenyl-p'-oxycarbonyl)-
4 '-(2-methylbutyloxycarbonyl) cyclohexane, optically active pn-alkyloxybenzylidene-p'-(2-methylbutyloxycarbonyl) aniline, etc.]. Further, it may contain a chiral compound having no liquid crystallinity and / or a dichroic dye, for example, an anthraquinone dye or an azo dye.

A liquid crystal composition exhibiting ferroelectricity causes an optical switching phenomenon when a voltage is applied, and a display element having a fast response utilizing this phenomenon can be produced (for example, JP-A-56-107216,
JP-A-59-118744, NA Clark (NACl
ark), ST Lagerwal
l); Applied Physics Letter
sics Lttetter) 36 , 899 (1980), etc.].

The liquid crystal composition of the present invention has a cell spacing of 0.5 to 10 μm.
m, preferably 0.5 to 3 μm in a liquid crystal cell,
By installing a polarizer on both sides, it can be used as an optical switching element (display element).

The above-mentioned liquid crystal cell can be manufactured by providing a transparent electrode and bonding two glass substrates whose surfaces are subjected to an alignment treatment with a spacer interposed therebetween.

Examples of the spacer include alumina beads, glass fibers, and polyimide films. As the orientation treatment method, a usual orientation treatment, for example, a polyimide film, a rubbing treatment, a SiO oblique deposition, or the like can be applied.

EXAMPLES Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

Example 1 Production of Compound No. 64 in Table 1 To 1.4 L of water containing 210 g of sodium hydrogencarbonate was added 187 g of orthofluorophenol and cooled to 10 ° C. or lower. Into this, 423 g of finely crushed iodine was charged in five portions. After confirming that the iodine color had disappeared, the mixture was extracted with toluene. The toluene layer was washed with water, washed with aqueous sodium hydrogen sulfite, and then with water, and then toluene was removed.
The reddish purple liquid obtained by vacuum distillation (bp 124 to 145 ° C / 18 mmHg) was recrystallized with hexane to obtain 120 g of o-fluoro-p-iodophenol as white crystals.

To a solution of 15.0 g of o-fluoro-p-iodophenol dissolved in 120 ml of dimethyl sulfoxide, aqueous sodium hydroxide (3.0 g of sodium hydroxide, 10 ml of water) was added, and the mixture was stirred until a uniform solution was obtained. Next, 10.4 g of n-hexyl bromide was added, and the mixture was stirred at room temperature for 3 days. After pouring the reaction solution into 1 L of ice water, it was extracted three times with hexane. After washing the hexane layer with water, the hexane was removed to obtain 16.7 g of oily pn-hexyloxy-m-fluoroiodobenzene.

9.5 g of 2,5-dibromopyridine and 4.0 g of 3-methyl-1-butyn-3-ol in 80 ml of triethylamine were used as catalysts to prepare bistriphenylphosphine valladium dichloride 32.
The reaction was carried out overnight at room temperature under a nitrogen atmosphere using 0 mg and 80 mg of copper (I) iodide. After the completion of the reaction, triethylamine was removed and extracted with toluene. The toluene layer was washed with hydrochloric acid, washed with water, and then toluene was removed to obtain 7.7 g of the following compound (a).

3.2 g of the compound (a) obtained in the above and 2.7 g of 1-decyne in 50 ml of triethylamine, 240 mg of bistriphenylphosphine palladium dichloride and 60 m of copper (I) iodide were used as catalysts.
Using g, the reaction was carried out at a reflux temperature under a nitrogen atmosphere for 5 hours.
After the completion of the reaction, triethylamine was removed and extracted with hexane. The hexane layer was washed with hydrochloric acid, washed with water, and then hexane was removed, followed by extraction with methanol. By removing methanol, 3.6 g of the following compound (b) was obtained.

Into a solution of 3.6 g of the compound (b) obtained in the above in 100 ml of dry toluene, 1.5 g of powdered sodium hydroxide was added, and the mixture was heated under reflux for 1 hour. After cooling, toluene was removed after washing with water. The obtained black oil was dissolved in hexane and separated and purified by a silica gel column to obtain 1.0 g of the following liquid compound (c).

1.0 g of the compound (c) obtained with 1.4 g of pn-hexyloxy-m-fluoroiodobenzene obtained in the above was used in 30 ml of triethylamine using 40 mg of bistriphenylphosphine palladium dichloride and 10 mg of copper (I) iodide as a catalyst. The reaction was carried out overnight at room temperature under a nitrogen atmosphere. After the completion of the reaction, triethylamine was removed and extracted with hexane. The hexane layer was washed with hydrochloric acid, washed with water, treated with a silica gel column, and then recrystallized twice with ethanol to obtain 0.47 g of the compound of the present invention as a white crystal, No. 64 in Table 1, which is a compound of the present invention. The structure of the compound was confirmed by NMR (nuclear magnetic resonance spectrum analysis), MS (mass spectrometry), IR (infrared absorption spectrum analysis) and elemental analysis. The IR, H-NMR and F-NMR spectra of the above compound are shown in FIGS. 1, 2 and 3, respectively.

Elemental analysis value: Theoretical value (%) Actual value (%) C: 80.37 C: 80.12 H: 8.31 H: 8.53 N: 3.23 N: 2.99 F: 4.39 F: 4.61 Example 2 Production of compound No. 48 in Table 1 25.0 g of p-iodophenol was added to dimethyl sulfoxide 2
Aqueous sodium hydroxide (5.0 g of sodium hydroxide, 20 ml of water) was added to the solution dissolved in 50 ml, and the mixture was stirred until a uniform solution was obtained. Next, 17.8 g of n-hexyl bromide was added and the mixture was stirred at room temperature for 3 days. After pouring the reaction solution into 1 L of ice water, it was extracted three times with hexane. After washing the hexane layer with water, the hexane is removed to obtain an oily pn-
29.5 g of hexyloxyiodobenzene was obtained.

29.5 g of pn-hexyloxyiodobenzene and 3-
12.4 g of methyl-1-butyn-3-ol was reacted in 150 ml of triethylamine at room temperature under nitrogen atmosphere at room temperature under a nitrogen atmosphere using 300 mg of bistriphenylphosphine palladium dichloride and 75 mg of copper (I) iodide as a catalyst. After the completion of the reaction, triethylamine was removed and extracted with hexane. The hexane layer was washed with 1N hydrochloric acid, washed with water, and then hexane was removed to obtain 23.2 g of the following compound (d) as a solid.
I got

In a solution prepared by dissolving 23.2 g of the compound (d) obtained in 1 above in 800 ml of dry toluene, 10.7 g of sodium hydroxide powder was added, and the mixture was heated under reflux for 1 hour. After cooling, toluene was removed after washing with water. The resulting black oil was extracted with methanol, and then methanol was removed to obtain an oily pn.
-12.8 g of hexyloxyphenylacetylene were obtained.

Pn-hexyloxyphenylacetylene obtained in
4.2 g and 5.0 g of 2,5-dibromopyridine in triethylamine 8
In 0 ml, the reaction was carried out overnight at room temperature under a nitrogen atmosphere using 160 mg of bistriphenylphosphine palladium dichloride and 40 mg of copper (I) iodide as a catalyst. After the completion of the reaction, triethylamine was removed and extracted with toluene. The toluene layer was washed with aqueous hydrochloric acid, washed with water, and then toluene was removed, followed by recrystallization from methanol to obtain 6.5 g of the following compound (e).

1.3 g of the compound (e) obtained with 1.0 g of 1-decyne in 40 ml of triethylamine, 80 mg of bistriphenylphosphine palladium dichloride and 20 mg of copper (I) iodide were used as catalysts.
The reaction was carried out at reflux temperature under a nitrogen atmosphere for 5 hours. After the completion of the reaction, triethylamine was removed and extracted with hexane. The hexane layer was washed with hydrochloric acid, washed with water, treated with a silica gel column, and then recrystallized twice with ethanol to obtain white crystals of the compound of the present invention in Table 1.
0.54 g of 48 compounds was obtained. The IR spectrum and H-NMR spectrum of the above compound are shown in FIG. 4 and FIG.
Shown in the figure.

Elemental analysis: Theoretical value (%) Actual value (%) C: 83.85 C: 83.62 H: 8.92 H: 9.03 N: 3.37 N: 3.60 Example 3 Production of compound No. 13 in Table 1 2-chloro-5- Nitropyridine 10.0 g in ethanol 1
The resulting solution was dissolved in 00 ml and reduced at room temperature under a hydrogen atmosphere with nitro group using platinum dioxide. When the absorption of hydrogen disappeared, the catalyst was removed by filtration, and ethanol was removed. By recrystallizing the obtained solid with toluene, 2-chloro-
5.8 g of 5-aminopyridine were obtained.

5.8 g of 2-chloro-5-aminopyridine obtained in 400 ml of water containing 45 g of 36% aqueous hydrochloric acid was added, and the mixture was cooled to 5 ° C or lower. A separately prepared aqueous solution of sodium nitrite (3.1 g of sodium nitrite, 30 ml of water) was dropped therein at 5 ° C. or lower. After the dropwise addition, the mixture was further stirred for 1 hour, and then an aqueous potassium iodide solution (15 g of potassium iodide, 30 ml of water) was added thereto, and the mixture was slowly returned to room temperature and stirred until no nitrogen was generated.
After completion of the reaction, sodium hydroxide was added to make the solution neutral, and then sodium bisulfite was added, followed by stirring for 1 hour.
The resulting precipitate was filtered, washed with water, and then recrystallized from hexane to obtain 7.3 g of 2-chloro-5-iodopyridine.

7.0 g of the 2-chloro-5-iodopyridine obtained in
3.2 g of octin in 100 ml of triethylamine, bistriphenylphosphine palladium dichloride 120 mg as a catalyst
And 30 mg of copper (I) iodide, and reacted for 5 hours under a nitrogen atmosphere. After the completion of the reaction, triethylamine was removed and extracted with hexane. The hexane layer was washed with hydrochloric acid, washed with water, and then treated with a silica gel column to give 5.9 g of the following compound (q) as an oil.

5.9 g of the compound (q) obtained in was dissolved in 80 ml of ethanol, and hydrogenation was carried out under a hydrogen atmosphere at normal pressure using platinum dioxide. When the absorption of hydrogen disappeared, the catalyst was removed by filtration, and ethanol was removed. The obtained liquid was dissolved in hexane and purified by a silica gel column to give 2-
5.4 g of chloro-5-octylpyridine were obtained.

Pn obtained in the same manner as in Example 1 except that n-octyl bromide was used instead of n-hexyl bromide.
-Octyloxy-m-fluoroiodobenzene and 3-
P-n-octyloxy- obtained by reacting methyl-1-butyn-3-ol in the same manner as in Example 2
1.5 g of 2-chloro-5-octylpyridine obtained with 1.6 g of m-fluorophenylacetylene was added to triethylamine 60
The mixture was refluxed under a nitrogen atmosphere for 8 hours using 48 mg of bistriphenylphosphine palladium dichloride, 12 mg of copper (I) iodide and 96 mg of triphenylphosphine as a catalyst in ml. After the completion of the reaction, triethylamine was removed and extracted with toluene. The toluene layer was washed with hydrochloric acid, washed with water, treated with a silica gel column, and then recrystallized three times with ethanol to obtain No. 13 in Table 1 of the compound of the present invention.
0.54 g of the compound was obtained. IR spectrum of the above compound,
The H-NMR spectrum and the F-NMR spectrum are shown in FIGS. 6, 7, and 8, respectively.

Elemental analysis: theoretical (%) actual (%) C: 79.64 C: 79.53 H: 9.15 H: 9.21 N: 3.20 N: 3.34 F: 4.35 F: 4.29 Phases of the compounds obtained in Examples 1 to 3. Table 3 shows transition temperatures.
Shown in

Each symbol in Table 3 represents the following phases.

Cry; crystalline phase Sc; smectic C phase N; nematic phase Iso; isotropic liquid phase; phase exists (); represents a monotropic phase. [Effect of the Invention] The present invention relates to a novel smectic C liquid crystal and smectic C. The present invention provides a smectic liquid crystal useful as a component of a liquid crystal composition, and these smectic liquid crystals have the following remarkable characteristics.

(1) The liquid crystal composition is required to have a negative dielectric anisotropy, but the smectic C liquid crystal of the present invention contains a halogen atom which is electron-withdrawing in the minor axis direction of the molecule and / or contains a nitrogen atom. Therefore, the dielectric anisotropy is negative, and is very useful as a component for making the dielectric anisotropy of the smectic C liquid crystal composition negative.

(2) Since the smectic C liquid crystal of the present invention has no smectic A phase, it has a large tilt angle, and is very useful as a component for adjusting the tilt angle of a practical liquid crystal composition.

(3) The smectic C liquid crystal of the present invention has a smectic C
Since there is no other liquid crystal phase on the lower temperature side than the phase, the temperature range of the smectic C phase can be expanded by mixing,
Very useful.

(4) Low viscosity because there is no ester bond in the molecule.

(5) Excellent compatibility with other smectic C liquid crystals.

(6) The orientation is very good because the molecules are rigid.

(7) Good stability against light, heat and moisture.

(8) Tolan-based optically active compound (tolan-based dopant)
And the structure is very similar, the compatibility with these compounds is very good.

(9) Since the liquid crystal compound of the present invention having a triple bond has a large birefringence, it can be added not only to the smectic C liquid crystal composition but also to the nematic liquid crystal composition to reduce the thickness of the liquid crystal display cell. To increase the response speed.

Due to the above effects, the liquid crystal compound of the present invention is a very useful substance in developing a practical ferroelectric smectic liquid crystal composition.

[Brief description of the drawings]

1, 2 and 3 show the IR, H-NMR and F-NMR spectra of the compound obtained in Example 1, respectively. FIGS. 4 and 5 show the compounds obtained in Example 2, respectively. FIG. 6, FIG. 7, and FIG. 8 show the IR and H-NMR of the compound obtained in Example 3, respectively.
1 shows -NMR and F-NMR spectra.

Continuation of the front page (72) Inventor Kuniyoshi Yoshio 11-11, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto-shi, Kyoto 1 Sanyo Chemical Industries Co., Ltd. (56) References JP-A-60-149564 (JP, A) JP-A-2 -258890 (JP, A) JP-A-2-62861 (JP, A) JP-A-3-145450 (JP, A) JP-A-2-503443 (JP, A) WO 88/7523 (WO, A1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C07D 213/00-213/30 C09K 19/00-19/34 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] (1) General formula [Wherein, R and R ′ are an alkyl group having 1 to 18 carbon atoms, X ₁ and X ₂ are a single bond (direct bond), —O—, —S— or —C≡C—, Y is -C≡C-, and A is a 1,4-biphenylene group which may be substituted with a fluorine atom or a chlorine atom (one or two CH groups present in these groups are replaced by N) ) Or 2,
6-naphthylene group Is a pyridine ring And A is In this case, _one of X ₁ and X ₂ is always -C≡C-)). 2. The pyridine liquid crystal compound according to claim 1, wherein Y is -C≡C-. 3. The pyridine-based liquid crystal compound according to claim 1, wherein two or three of the groups represented by X ₁ , X ₂ and Y are —C≡C—. 4. A is The pyridine-based liquid crystal compound according to any one of claims 1 to 3, wherein 5. A liquid crystal composition containing at least two kinds of compounds, wherein one of the compounds is a liquid crystal composition.
The liquid crystal composition, which is the pyridine-based liquid crystal compound according to any one of the above. 6. A liquid crystal display containing the liquid crystal composition according to claim 5.