JP2005232071A - Pyrazole derivative - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen-bonded liquid crystal compound of new structure, and to provide a liquid crystal composition containing the same. <P>SOLUTION: The new compound is a pyrazole derivative of general formula(1)[ wherein, X<SP>1</SP>and X<SP>2</SP>are each a single bond or a linkage group selected from C≡C, CH=CH, CH=N, OCO, COO, CONH, CO, COCH<SB>2</SB>, OCH<SB>2</SB>, CH<SB>2</SB>NH, O, (CH<SB>2</SB>)<SB>n</SB>( n is ≥2 ), S and NH; Ar<SP>1</SP>and Ar<SP>2</SP>are each a (substituted) aromatic ring or aliphatic ring; m and n are each 0-2( wherein, m+n≥1 ); R<SP>1</SP>is a 1-20C alkyl, 1-20C alkoxy, 1-20C thioalkyl, cyano, nitro or a halogen atom ]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel liquid crystal compound, and more particularly to a hydrogen bonding liquid crystal compound.

  Until now, liquid crystal compounds utilizing various intermolecular interactions (hydrogen bonds, ionic interactions, charge transfer interactions, ion / dipole interactions, fluorine / fluorine interactions, etc.) have been synthesized. A system that exhibits liquid crystallinity by assembling and self-organizing heterogeneous or homogeneous molecules with a hydrogen bond as a driving force is called a hydrogen-bonding liquid crystal compound. This system is known as a complex (A) of 4-alkoxybenzoic acid which is a hydrogen bond donor and a stilbazole derivative which is a hydrogen bond acceptor by Kato and Frechet (see, for example, Patent Document 1). The compound has a nematic phase and a smectic phase, and is expected to be used as a next-generation material in the fields of advanced materials and biomaterials.

  In addition, there are many known systems that exhibit liquid crystallinity by heterogeneous or homogenous molecules gathering and self-organizing with hydrogen bonds as an intermediate (see, for example, Non-Patent Document 1). Since these compounds also have liquid crystalline properties such as a smectic phase and a discotic phase, they are expected to be used in the fields of advanced materials and biomaterials as next-generation materials.

  On the other hand, regarding the liquid crystal compound having a pyrazole ring, 3,5-bis (pn-alkoxyphenyl) pyrazole (B) having an alkoxyphenyl group introduced at the 3,5-positions of pyrazole shown below exhibits a smectic liquid crystal phase. It has been reported (for example, refer nonpatent literature 2).

However, this smectic liquid crystal phase is not a hydrogen-bonded liquid crystal that is expressed as a result of the assembly and self-organization of molecules through hydrogen bonds, but a hydrogen that utilizes pyrazole itself as a hydrogen bond donor and hydrogen bond acceptor. No bondable liquid crystal compound has been known so far.
US 5,139,696 Liquid Crystal, Vol. 4, No. 1, 2000, p4 Mol. Cryst. Liq. Cryst., 1993, Vol.225, pp. 175-182

  An object of the present invention is to provide a hydrogen-bonding liquid crystal compound having a novel structure, and further to provide a liquid crystal composition containing the compound.

  As a result of diligent research to achieve the above-mentioned problems, the present inventor exhibited liquid crystallinity by the pyrazole derivative having a specific substituent introduced at the 4-position of the pyrazole ring being assembled and self-organized with a hydrogen bond as an intermediate. The present inventors have found that the compound and a liquid crystal composition containing the compound are useful as materials for an optical sensor, a thin film transistor, a light emitting material, a solar cell and the like, and have completed the present invention.

  That is, the following general formula (1):

[Wherein, X ¹ and X ² may be the same or different, and —C≡C—, —CH═CH—, —CH═N—, —OCO—, —COO—, —CONH—, —CO —, —COCH ₂ —, —OCH ₂ —, —CH ₂ NH—, —O—, — (CH ₂ ) _n — (n represents a number of 2 or more), —S— and —NH—. A linking group or a single bond is shown, Ar ¹ and Ar ² may be the same or different and each represents an aromatic ring or an aliphatic ring which may have a substituent, and m and n are each 0-2 (provided that M + n ≧ 1), and R ¹ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, a cyano group, a nitro group, or a halogen atom. ]
The pyrazole derivative represented by these is provided.

  The present invention also provides a liquid crystal compound comprising the pyrazole derivative.

  The present invention also provides a liquid crystal composition containing the pyrazole derivative.

  The pyrazole derivative of the present invention becomes a hydrogen bonding liquid crystal compound having a smectic phase by dimerization by hydrogen bonding of the pyrazole ring. Therefore, the compound and the liquid crystal composition containing the compound are useful as a material for a liquid crystal display, a liquid crystalline organic semiconductor, a metal ion sensor, and the like.

が結合してなるものであり、棒状のスメクチック液晶性を発現する。 The pyrazole derivative (1) of the present invention has the following group at the 4-position of the pyrazole ring:

Are bonded and exhibit rod-like smectic liquid crystallinity.

Here, X ¹ and X ² may be the same or different and are —C≡C—, —CH═CH—, —CH═N—, —OCO—, —COO—, —CONH—, —CO—. , —COCH ₂ —, —OCH ₂ —, —CH ₂ NH—, —O—, — (CH ₂ ) _n — (n represents a number of 2 or more), —S— and —NH—. Indicates a group or a single bond. Such a linking group is a linking group that a general liquid crystal compound has. Among these, in the present invention, —C≡C—, —CH═CH—, —OCO—, —COO— or a single bond is particularly preferable.

Ar ¹ and Ar ² represent an aromatic ring or an aliphatic ring which may have a substituent.
Here, examples of the aromatic ring include a 6π electron aromatic ring and a 10π electron aromatic ring. Examples of the 6π electron aromatic ring include benzene, pyridine, pyrimidine, pyridazine, pyrazine, thiophene, furan, pyrrole, thiazole, oxazole, thiadiazole, and oxadiazole, and among these, benzene, pyridine, and thiophene are preferable. Examples of the 10π-electron aromatic ring include naphthalene, quinoline, isoquinoline, quinoxaline, indole, benzothiophene, benzofuran, benzimidazole, benzoxazole, and benzothiazole, and among these, naphthalene is preferable.

  Examples of the aliphatic ring include saturated or unsaturated cyclic hydrocarbon groups having 3 to 10 carbon atoms, such as cycloalkanes such as cyclopropane, cyclobutane, cyclopentane, and cyclohexane, and cycloalkenes such as cyclopropene and cyclohexene. Of these, cyclohexane and bicyclo [2.2.2] octane are preferred.

  Examples of the group that can be substituted with such an aromatic ring or aliphatic ring include halogen atoms such as chlorine and fluorine, cyano group, nitro group, and alkoxy group.

  m and n are each independently 0 to 2 and m + n ≧ 1. A preferred embodiment of m and n is 0 or 1.

R ¹ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, a cyano group, a nitro group, or a halogen atom. Such substituents are all terminal substituents of general liquid crystal compounds.
Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, and an alkoxy group having 1 to 20 carbon atoms. Is, for example, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentoxy group, or an alkylthio group having 1 to 20 carbon atoms, such as a methylthio group, an ethylthio group, an n-propylthio group, n -A butylthio group, n-pentylthio group, etc. are mentioned. Among these, in order to develop a stable liquid crystal phase, the number of carbon atoms is preferably 6 to 12, and particularly an alkyl group having 6 to 12 carbon atoms (hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group). Group, dodecyl group) and an alkoxy group having 6 to 12 carbon atoms (hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group) are preferable.

As the pyrazole derivative represented by the general formula (1) of the present invention, for example, as shown by the following formula, the compound (3) or the compound (4) obtained from the compound (2) and the compound (5) are publicly known. Can be synthesized by deprotecting the trityl (—CPh ₃ ) group with a 90% aqueous acetic acid solution after coupling by a method such as Suzuki coupling or Sonogashira coupling. In addition, coupling reactions such as Stille coupling and Grignard coupling can also be used.

[Wherein R ¹ , A ¹ , A ² , X ¹ , X ² , m, n are the same as those described above, X ³ is a halogen atom such as I, Br, Cl, etc., a triflate group (—OTf), A leaving group such as a tributylstannyl group (—Sn ⁿ Bu ₃ ), a trioctyl tin group (—Sn ⁿ Octyl ₃ ), or a hydrogen atom is shown. ]

  Here, the reaction from the compound (2) to the compound (3) can be performed by, for example, reacting the compound (2) with triethylamine and triphenylmethane bromide in THF at room temperature for 24 hours.

  The reaction from compound (3) to compound (4) can be carried out, for example, by using compound (3), bis (pinacolato) diboron and potassium acetate and a catalytic amount of [1,1′-bis (diphenylphosphino) ferrocene] in DMF. It can be performed by reacting dichloropalladium at 80 ° C. for 24 hours.

The coupling reaction between the compound (3) or the compound (4) and the compound (5) may be a known Suzuki coupling reaction or Sonogashira coupling reaction. For example, the Suzuki coupling reaction between compound (4) and compound (5) is carried out by using compound (4), compound (5), sodium carbonate and a catalytic amount of tetrakis (triphenylphosphine) palladium in DME (ethylene glycol dimethyl ether) / water. This can be carried out by reacting (0) with heating under reflux for 5 to 10 hours. The bacterial head coupling reaction between compound (3) and compound (5) was carried out in triethylamine / piperidine using compound (3), compound (5), catalytic amounts of copper iodide and bis (triphenylphosphine) palladium (II). ) Dichloride can be reacted by reacting at 80 ° C. for 5 hours.
The elimination of the trityl group may be performed in a 90% aqueous acetic acid solution under heating and refluxing for 12 to 24 hours.

  Since the pyrazole derivative thus obtained is dimerized by hydrogen bonding of nitrogen of the pyrazole ring, it becomes a hydrogen bonding liquid crystal compound exhibiting a smectic phase (see Examples).

  The pyrazole derivative of the present invention can be a liquid crystal composition containing one or more of them, and other liquid crystalline or non-liquid crystalline compounds, synthetic organic polymers, and the like. Any other known liquid crystal compound and non-liquid crystal compound can be used. Examples of the synthetic organic polymer include thermoplastic polymers, thermosetting polymers, engineering plastics, and conductive polymers. Such a liquid crystal composition may further contain various additives. Examples of the additive include a plasticizer, a colorant, and a dopant. The liquid crystal composition may further contain a reinforcing material such as glass fiber, carbon fiber, or boron fiber.

Hereinafter, the present invention will be described based on examples. However, the present invention is not limited to the following examples.
The ¹ H-NMR spectrum was measured using JEOL JNM-LA400. At this time, ¹ H-NMR: tetramethylsilane was used as an internal standard.
The UV-Vis spectrum was measured using UV-2400PC manufactured by Shimadzu Corporation.
GCMS-QP5050A from Shimadzu Corporation was used for mass spectrometry.
The phase transition temperature and the phase transition enthalpy were measured using a differential scanning calorimeter SSC / 5200 manufactured by Seiko Instruments Inc.
A polarization microscope with a hot stage; Mettler FP82 Hot Stage, OLYMPUS BH-2, and Mettler FP80 Central Processor were used for observation of the optical texture.
Cry, M, and Iso represent a crystal phase, a liquid crystal phase (intermediate phase), and an isotropic liquid, respectively.

Example 1 4- (4′-octyloxyphenyl) -pyrazole

(1) Synthesis of 4-octyloxyphenylboronic acid

  An n-butyllithium / hexane solution (17.53 mmol) was added to a diethyl ether solution of 1-bromo-4-octyloxybenzene (17.53 mmol) cooled to −70 ° C. and reacted at room temperature for 3 hours. The mixture was cooled again to 60 ° C., trimethyl borate (17.53 mmol) was added dropwise, and the mixture was reacted at room temperature for 12 hours. The reaction solution was ice-cooled, diluted aqueous hydrochloric acid was added, neutralized with saturated brine, and washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to give 4-octyloxyphenylboronic acid (white crystals, 17.19 mmol). Yield 92%.

(2) Synthesis of 2-trityl-4- (4′-octyloxyphenyl) -pyrazole

  1-bromo-4-octyloxybenzene (16.99 mmol), 2-trityl-4-bromopyrazole (16.99 mmol), sodium carbonate (33.98 mmol), tetrakis (triphenylphosphine) palladium (0) (0. 5097 mmol) of ethylene glycol dimethyl ether / water solution was heated to reflux for 5 hours, then cooled with water and extracted with 100 mL of chloroform. Subsequently, it neutralized with the saturated salt solution and washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to obtain 2-trityl-4- (4′-octyloxyphenyl) -pyrazole (white powder, 9.209 mmol). Yield 54%.

(3) Synthesis of 4- (4′-octyloxyphenyl) -pyrazole

  2-Trityl-4- (4′-octyloxyphenyl) -pyrazole (9.209 mmol) suspended in 90% aqueous acetic acid was heated at 110 ° C. for 11 and a half hours. After returning to room temperature, saturated aqueous sodium hydrogen carbonate solution was added until the reaction mixture became weakly alkaline, and the mixture was extracted with ethyl acetate. Subsequently, it neutralized with the saturated salt solution. The organic layer was dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to obtain a crude product. The crude product was chromatographed with toluene / ethyl acetate, and the resulting product was further washed with ethyl acetate / hexane to give 4- (4′-octyloxyphenyl) -pyrazole (white powder, 4. 419 mmol). Yield 45%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.89 (t, J = 7.1Hz, 3H), 1.32 (m, 8H), 1.45 (m, 2H), 1.80 (m, 2H), 3.98 (t, J = 6.6Hz, 2H), 6.93 (d, J = 8.8Hz, 2H), 7.41 (d, J = 8.8Hz, 2H) 7.87 (s, 2H).
From the above analysis results, it was confirmed that the obtained compound was the title compound.
UV-Vis spectrum; λ _max = 253.8 nm (log ε 4.23)
DSC measurement results and optical texture observation;
Heating; Cry 130.7 ° C. (14.14 kJ / mol) → M 189.7 ° C. (33.18 kJ / mol) → Iso
Cooing: Iso185.2 ° C. (−31.08 kJ / mol) → M124.0 ° C. (−9.45 kJ / mol) → Cry
Heating; Cry 128.5 ° C. (8.85 kJ / mol) → M 189.8 ° C. (29.91 kJ / mol) → Iso
The liquid crystal phase showed a mosaic pattern and was identified as a smectic B phase on the optical texture.

Example 2 4- (4'-pentylphenylethynyl) -pyrazole

(1) Synthesis of 2-trityl-4-iodopyrazole

  A tetrahydrofuran solution of 4-iodopyrazole is added dropwise to a tetrahydrofuran solution of triphenylmethane bromide (56.51 mmol) and triethylamine (56.51 mmol) cooled on ice. After reacting at room temperature for 12 hours, the mixture is cooled on ice and 20 mL of water is added. Thereafter, the precipitate was collected by filtration and washed with 50 mL of water and 50 mL of methanol to obtain 2-trityl-4-iodopyrazole (white powder, 32.80 mmol). Yield 61%.

(2) Synthesis of 2-trityl-4- (4′-pentylphenylethynyl) -pyrazole

  2-trityl-4-iodopyrazole (22.92 mmol), p-ethynylpentylbenzene (22.92 mmol), triethylamine 300 mL, copper iodide (1.146 mmol), piperidine 60 mL, dichlorobis (triphenylphosphine) palladium (0) The suspension of (2.292 mmol) is reacted at 80 ° C. for 4 and a half hours. Thereafter, the ice-cooled reaction solution is neutralized with hydrochloric acid and extracted with toluene. The organic layer was washed with saturated brine and washed with water. Then, it was dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain 2-trityl-4- (4′-pentylphenylethynyl) -pyrazole (cream powder, 17.56 mmol). Yield 77%.

(3) Synthesis of 4- (4′-pentylphenylethynyl) -pyrazole

2-Trityl-4- (4′-pentylphenylethynyl) -pyrazole (17.56 mmol) suspended in 90% aqueous acetic acid was heated at 130 ° C. for 17 and a half hours. After returning to room temperature, saturated aqueous sodium hydrogen carbonate solution was added until the reaction mixture became weakly alkaline, and the mixture was extracted with 200 mL of chloroform. Subsequently, the mixture was neutralized with saturated saline and washed with water. It was dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain a crude product. The crude product was chromatographed with toluene / ethyl acetate and the resulting product was further recrystallized with hexane / ethyl acetate to give 4- (4′-pentylphenylethynyl) -pyrazole (white powder, 1.612 mmol). Got. Yield 9%.
¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.89 (t, J = 7.1Hz, 3H), 1.32 (m, 4H), 1.61 (m, 2H), 2.60 (t, J = 8.1Hz, 2H), 7.14 (d, J = 8.1Hz, 2H), 7.40 (d, J = 8.1Hz, 2H) 7.78 (s, 2H), 9.74 (br, 1H).
Mass spectrometry Calculated value: 238.33, experimental value: 238
From the above analysis results, it was confirmed that the obtained compound was the title compound.
UV-Vis spectrum; λ _max = 260.8 nm (log ε 4.21), 275.6 nm (log ε 4.29), 291.8 nm (log ε 4.17)
DSC measurement results and optical texture observation;
Heating; Cry 104.8 ° C. (4.77 kJ / mol) → M 126.9 ° C. (17.61 kJ / mol) → Iso
The liquid crystal phase showed a mosaic pattern and was identified as a smectic B phase on the optical texture.

Example 3 4- (5'-pentyl-2'-thienyl) -pyrazole

(1) Synthesis of 2-pentyl-5-boron dimethoxide thiophene

  An n-butyllithium / hexane solution (36.30 mmol) was added to a diethyl ether solution of 2-pentylthiophene (36.30 mmol) cooled to −78 ° C., reacted at room temperature for 4 hours, and then cooled again to −78 ° C. Then, trimethyl borate (36.30 mmol) was added dropwise and reacted at room temperature for 12 hours. Thereafter, the inorganic salt was removed by Celite filtration, and then the solvent was distilled off under reduced pressure to obtain 2-pentyl-5-boron dimethoxide thiophene (light yellow oil, 32.99 mmol). Yield 91%.

(2) Synthesis of 2-trityl-4- (5′-pentyl-2′-thienyl) -pyrazole

  2-trityl-4-bromopyrazole (12.84 mmol), 2-pentyl-5-boron dimethoxide thiophene (14.13 mmol), sodium carbonate (25.68 mmol), tetrakis (triphenylphosphine) palladium (0) (0 .3852 mmol) of ethylene glycol dimethyl ether / water solution was heated to reflux for 7 and a half hours, then cooled with water and extracted with 200 mL of chloroform. Next, the mixture was neutralized with saturated saline and washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain a crude product. Then, after chromatographic purification with ethyl acetate / hexane, recrystallization from ethyl acetate / hexane gave 2-trityl-4- (5′-pentyl-2′-thienyl) -pyrazole (light yellow solid, 6.527 mmol). Obtained. Yield 51%.

(3) Synthesis of 4- (5'-pentyl-2'-thienyl) -pyrazole

  2-Trityl-4- (5′-pentyl-2′-thienyl) -pyrazole (6.528 mmol) suspended in 90% aqueous acetic acid was heated at 110 ° C. for 16 and a half hours. After returning to room temperature, saturated aqueous sodium hydrogen carbonate solution was added until the reaction mixture became weakly alkaline, and the mixture was extracted with 300 mL of ethyl acetate. Subsequently, it neutralized with the saturated salt solution and washed with water. It was dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain a crude product. Chromatographic purification with toluene / ethyl acetate gave 4- (5′-pentyl-2′-thienyl) -pyrazole (light yellow solid, 4.493 mmol). Yield 69%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.91 (t, J = 7.3Hz, 3H), 1.37 (m, 4H), 1.69 (m, 2H), 2.79 (t, J = 7.3Hz, 2H), 6.68 (d, J = 3.4Hz, 1H), 6.90 (d, J = 3.4Hz, 1H), 7.73 (s, 2H).
Mass spectrometry Calculated value: 220.33, experimental value: 220
From the above analysis results, it was confirmed that the obtained compound was the title compound.
UV-Vis spectrum; λ _max = 277.8 nm (log ε 4.18)
DSC measurement results;
Heating; Cry 66.2 ° C. (2.12 kJ / mol) → M 99.4 ° C. (24.21 kJ / mol) → Iso
DSC measurement revealed the presence of liquid crystal phase.

Example 4 4-[(E) -4'-decyloxystilbazolyl] -pyrazole

(1) Synthesis of (E) -4-bromo-4'-decyloxystilbene

  A solution of 4-decyloxyiodobenzene (7.328 mmol), 4-bromostyrene (6.662 mmol), triethylamine (7.328 mmol), and palladium (II) acetate (0.220 mmol) in acetonitrile was heated at 100 ° C. for 24 hours. . After cooling to room temperature, 50 mL of a 10% aqueous hydrochloric acid solution was added dropwise, and the mixture was extracted with 300 mL of ethyl acetate. Next, the mixture was washed with saturated saline and neutralized, and then washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to obtain a crude product. This was chromatographed with ethyl acetate / hexane to obtain the desired product (white powder, 3.202 mmol). Yield 48%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.88 (t, J = 7.1Hz, 3H), 1.28-1.46 (m, 14H), 1.78 (m, 2H), 3.97 (t, J = 6.6Hz, 2H), 6.88 (d, J = 8.8Hz, 2H ), 6.89 (d, J = 16.3Hz, 1H), 7.04 (d, J = 16.3Hz, 1H), 7.34 (d, J = 8.3Hz, 2H), 7.42 (d, J = 8.6Hz, 2H), 7.45 (d, J = 8.5Hz, 2H).
From the above analysis results, it was confirmed that the obtained compound was the title compound.

(2) Synthesis of 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -pyrazole

2-trityl-4-bromopyrazole (9.842 mmol), bis (pinacolato) diboron (11.81 mmol), potassium acetate (29.53 mmol), [1,1′-bis (diphenylphosphino) ferrocene] dichloropalladium ( II) A solution of (0.5905 mmol) in dimethylformamide is heated at 80 ° C. for 24 hours. The reaction solution was ice-cooled, 50 mL of water was added, and the mixture was extracted with 50 mL of ethyl acetate. Subsequently, the organic layer was washed with saturated brine to neutralize, dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain a crude product. This was washed with acetone to obtain 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -pyrazole (white powder, 6.875 mmol). . Yield 70%.
¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
1.30 (s, 12H), 7.12-7.14 (m, 6H), 7.26-7.30 (m, 6H), 7.75 (s, 1H), 7.94 (s, 1H).
From the above analysis results, it was confirmed that the obtained compound was the title compound.

(3) Synthesis of 2-trityl-4-[(E) -4'-decyloxystilbazolyl] -pyrazole

  (E) -4-Bromo-4'-decyloxystilbene (1.533 mmol), 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -After the reaction with ethylene glycol dimethyl ether / water solution of pyrazole (1.533 mmol), sodium carbonate (3.066 mmol), tetrakis (triphenylphosphine) palladium (0) (0.046 mmol) for 4 and a half hours, the reaction was performed. After cooling to room temperature, 100 mL of water was added and extracted with 350 mL of chloroform. Next, the organic layer was washed with saturated brine, neutralized, washed with water, dried over sodium sulfate, filtered and semi-concentrated, and the precipitated solid was collected by filtration. This solid was washed with acetone and dried under reduced pressure to obtain 2-trityl-4-[(E) -4'-decyloxystilbazolyl] -pyrazole (white powder, 0.826 mmol). Yield 54%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.88 (t, J = 7.1Hz, 3H), 1.28-1.46 (m, 14H), 1.78 (m, 2H), 3.97 (t, J = 6.6Hz, 2H), 6.88 (d, J = 8.75Hz, 2H ), 6.94 (d, J = 16.3Hz, 1H), 7.03 (d, J = 16.6Hz, 1H), 7.21 (m, 6H), 7.32-7.34 (m, 9H), 7.39-7.44 (m, 6H) , 7.63 (s, 1H), 7.96 (s, 1H).
Mass spectrometry Calculated value: 644.38, experimental value: 645
From the above analysis results, it was confirmed that the obtained compound was the title compound.

(4) Synthesis of 4-[(E) -4'-decyloxystilbazolyl] -pyrazole

2-Trityl-4-[(E) -4′-decyloxystilbazolyl] -pyrazole (0.8264 mmol) suspended in 90% aqueous acetic acid was heated at 120 ° C. for 22 hours. After returning to room temperature, water was added and the precipitate was collected by filtration. This solid was suspended in 400 mL of ethyl acetate, washed with saturated brine, and washed with water. The organic layer was concentrated as it was and dried under reduced pressure. The obtained crude product was washed with toluene / ethyl acetate, and the target product was collected by filtration and dried under reduced pressure to give 4-[(E) -4'-decyloxystilbazolyl] -pyrazole (white powder, 0 .630 mmol). Yield 76%.
Since this compound was hardly soluble in a deuterated solvent for NMR measurement, identification by NMR was difficult.
DSC measurement results;
Heating; Cry 158.7 ° C. (5.96 kJ / mol) → MI 200.6 ° C. (12.68 kJ / mol) → MII 214.3 ° C. (0.97 kJ / mol) → MIII 306.9 ° C. (28 50 kJ / mol) → Iso
DSC measurement revealed the presence of liquid crystal phase.

Example 5 4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole

(1) Synthesis of 1-bromo-4- (4'-decyloxyphenylcarbonyloxy) benzene

  A tetrahydrofuran solution of p-decyloxybenzoic acid (35.92 mmol), p-bromophenol (35.92 mmol), dicyclohexylcarbodiimide (35.92 mmol), dimethylaminopyridine (3.592 mmol) is stirred at room temperature for 3 days. The precipitate was removed by filtration, and the filtrate was concentrated and dried under reduced pressure. This was chromatographed from hexane / ethyl acetate to give 1-bromo-4- (4'-decyloxyphenylcarbonyloxy) benzene (white solid, 26.90 mmol). Yield 75%.

(2) Synthesis of 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -pyrazole

  2-trityl-4-bromopyrazole (16.41 mmol), bis (pinacolato) diboron (19.69 mmol), potassium acetate (49.22 mmol), [1,1′-bis (diphenylphosphino) ferrocene] dichloropalladium ( II) A solution of (0.9840 mmol) in dimethylformamide is heated at 80 ° C. for 24 hours. The reaction solution was ice-cooled, 100 mL of water was added, and the mixture was extracted with 200 mL of ethyl acetate. Subsequently, the organic layer was washed with saturated brine to neutralize, dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain a crude product. This was washed with acetone to obtain 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -pyrazole (gray powder, 12.44 mmol). . Yield 76%.

(3) Synthesis of 2-trityl-4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole

  1-Bromo-4- (4'-decyloxyphenylcarbonyloxy) benzene (4.283 mmol), 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2 -Il) -pyrazole (4.079 mmol), sodium carbonate (8.158 mmol), tetrakis (triphenylphosphine) palladium (0) (0.1220 mmol) in ethylene glycol dimethyl ether / water solution was reacted by heating under reflux for 10 hours. Thereafter, the mixture was cooled to room temperature, added with 50 mL of water, and extracted with 100 mL of chloroform. Next, the organic layer was washed with saturated brine, neutralized, washed with water, dried over sodium sulfate, filtered and semi-concentrated, and the precipitated solid was collected by filtration. This solid was dried under reduced pressure to give 2-trityl-4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole (white powder, 2.806 mmol). Yield 69%.

(4) Synthesis of 4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole

  2-Trityl-4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole (2.806 mmol) suspended in 90% aqueous acetic acid was heated at 120 ° C. for 40 hours. Thereafter, water was added and the precipitate was collected by filtration, and the solid was suspended in 200 mL of ethyl acetate, washed with saturated brine, washed with water, and the organic layer was concentrated and dried under reduced pressure. Was chromatographed with toluene / ethyl acetate to give 4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole (white powder, 1.355 mmol). Yield 48%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.89 (t, J = 7.1Hz, 3H), 1.28 (m, 14H), 1.48 (m, 2H), 1.81 (m, 2H), 4.05 (t, J = 6.3 Hz, 2H), 6.97 (d, J = 8.8Hz, 2H), 7.23 (d, J = 8.3Hz, 1H), 7.55 (d, J = 8.3Hz, 2H), 7.89 (s, 2H), 8.15 (d, J = 8.8Hz, 2H).
From the above analysis results, it was confirmed that the obtained compound was the title compound.
UV-Vis spectrum;
λ _max = 300.0 nm (log ε 4.73), 282.0 nm (log ε 4.88)
DSC measurement results;
Cry 121.2 ° C. (4.75 kJ / mol) → MI 152.9 ° C. (0.42 kJ / mol) → MII 163.7 ° C. (3.41 kJ / mol) → MIII 222.1 ° C. (42.39 kJ / mol) → Iso
DSC measurement revealed the presence of liquid crystal phase.

（１）1−ブロモ−４−（４′−デシルオキシフェニルカルボニルオキシ）ベンゼンの合成

Example 6 4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole

(1) Synthesis of 1-bromo-4- (4'-decyloxyphenylcarbonyloxy) benzene

  A tetrahydrofuran solution of p-decyloxyphenol (7.988 mmol), p-bromobenzoic acid (7.988 mmol), dicyclohexylcarbodiimide (7.988 mmol), and dimethylaminopyridine (0.799 mmol) is stirred at room temperature for 3 days. . The precipitate was removed by filtration, and the filtrate was concentrated and dried under reduced pressure. This was chromatographed from hexane / ethyl acetate to give 1-bromo-4- (4'-decyloxyphenylcarbonyloxy) benzene (white solid, 5.076 mmol). Yield 64%.

(2) Synthesis of 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -pyrazole

  2-trityl-4-bromopyrazole (9.84 mmol), bis (pinacolato) diboron (11.81 mmol), potassium acetate (29.53 mmol), [1,1′-bis (diphenylphosphino) ferrocene] dichloropalladium ( II) A solution of (0.5905 mmol) in dimethylformamide is heated at 80 ° C. for 24 hours. The reaction solution was ice-cooled, 100 mL of water was added, and the mixture was extracted with 200 mL of ethyl acetate. Subsequently, the organic layer was washed with saturated brine to neutralize, dried over sodium sulfate, filtered, concentrated and dried under reduced pressure to obtain a crude product. This was washed with acetone to obtain 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl) -pyrazole (gray powder, 6.24 mmol). . Yield 63%.

(3) Synthesis of 2-trityl-4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole

  1-Bromo-4- (4'-decyloxyphenylcarbonyloxy) benzene (3.00 mmol), 2-trityl-4- (4,4,5,5-tetramethyl-1,3,2-dioxaboron-2 -Il) -pyrazole (3.00 mmol), sodium carbonate (6.00 mmol), tetrakis (triphenylphosphine) palladium (0) (0.09 mmol) in ethylene glycol dimethyl ether / water solution was reacted by heating under reflux for 9 hours. Thereafter, the mixture was cooled to room temperature, added with 50 mL of water, and extracted with 100 mL of chloroform. Next, the organic layer was washed with saturated brine, neutralized, washed with water, dried over sodium sulfate, filtered and semi-concentrated, and the precipitated solid was collected by filtration. This solid was dried under reduced pressure to obtain 2-trityl-4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole (white powder, 1.99 mmol). Yield 66%.

(4) Synthesis of 4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole

  2-Trityl-4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole (1.991 mmol) suspended in 90% aqueous acetic acid was heated at 120 ° C. for 40 hours. Thereafter, the mixture was neutralized by adding an aqueous sodium hydrogen carbonate solution, extracted with ethyl acetate, washed with saturated brine, washed with water, dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to obtain a crude product. This was washed with ethyl acetate to obtain 4- [4 ′-(4 ″ -decyloxyphenylcarbonyloxy) phenyl] -pyrazole (white powder, 1.991 mmol). Yield 100%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.89 (t, J = 7.1Hz, 3H), 1.28 (m, 14H), 1.46 (m, 2H), 1.79 (m, 2H), 3.96 (t, J = 6.8Hz, 2H), 6.92 (d, J = 8.8Hz, 2H), 6.94 (d, J = 9.0Hz, 1H), 7.64 (d, J = 8.3Hz, 2H), 7.99 (s, 2H), 8.21 (d, J = 8.5Hz, 2H).
From the above analysis results, it was confirmed that the obtained compound was the title compound.
UV-Vis spectrum;
λ _max = 299.8 nm (log ε 5.01), 290.0 nm (log ε 4.96), 282.2 nm (log ε 5.09)
DSC measurement results;
Heating; Cry 154.8 ° C. (7.28 kJ / mol * ¹ ) → MI 162.0 ° C. (7.28 kJ / mol * ¹ ) → MII 197.3 ° C. (20.10 kJ / mol * ² ) → MIII 01.8 ° C. (20 .10kJ / mol * ² ) → Iso
* ¹ Total value of Cry → MI and MI → MII, * ² Total value of MII → MIII and MIII → Iso.
DSC measurement revealed the presence of liquid crystal phase.

Example 7 trans-4- [4 '-(4 "-pentylcyclohexyl) phenyl] -pyrazole

(1) Synthesis of trans-2-trityl-4- [4 ′ (4 ″ -pentylcyclohexyl) phenyl] -pyrazole

  Trans-4- (4'-pentylcyclohexyl) -phenylboronic acid (12.84 mmol), 2-trityl-4-bromopyrazole (12.84 mmol), sodium carbonate (25.68 mmol), tetrakis (triphenylphosphine) palladium (0) (0.3852 mmol) of ethylene glycol dimethyl ether / water solution was reacted by heating under reflux for 8 hours, cooled to room temperature, added with 200 mL of water, and extracted with 200 mL of chloroform. Next, the organic layer was washed with saturated brine, neutralized, washed with water, dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to obtain a crude product. This solid was washed with ethyl acetate and then dried under reduced pressure to obtain trans-2-trityl-4- [4 ′ (4 ″ -pentylcyclohexyl) phenyl] -pyrazole (white powder, 7.665 mmol). 60%.

(2) Synthesis of trans-4- [4 '-(4 "-pentylcyclohexyl) phenyl] -pyrazole

  Trans-2-trityl-4- [4 ′-(4 ″ -pentylcyclohexyl) phenyl] -pyrazole (7.666 mmol) suspended in 90% aqueous acetic acid was heated for 16 hours at 110 ° C. After returning to room temperature. The mixture was neutralized with an aqueous sodium hydrogen carbonate solution, extracted with ethyl acetate, washed with saturated brine, washed with water, dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to give a crude product. Was purified by chromatography from toluene / ethyl acetate to give trans-4- [4 ′-(4 ″ -pentylcyclohexyl) phenyl] -pyrazole (white powder, 4.048 mmol). Yield 53%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.89 (t, J = 7.3Hz, 3H), 1.00-1.10 (m, 2H), 1.19-1.34 (m, 9H), 1.40-1.51 (m, 2H), 1.89 (t, J = 11.5Hz, 4H) , 2.47 (m, 1H), 7.22 (d, J = 8.1Hz, 2H), 7.43 (d, J = 8.3Hz, 2H), 7.84 (s, 2H).
Mass spectrometry Calculated value: 296.45, experimental value: 296
From the above analysis results, it was confirmed that the obtained compound was the title compound.
UV-Vis spectrum; λ _max = 250.6 nm (log ε4.26)
DSC measurement results;
Heating; Cry 262.1 ° C. (34.4 kJ / mol) → Iso

Example 8 Liquid Crystal Composition 4- (4′-Octyloxyphenyl) -pyrazole obtained in Example 1 and 4-[(E) -4′-decyloxystilbazolyl] obtained in Example 4 -Pyrazole was mixed at a molar ratio of 1: 1, and the optical structure was observed by DSC. The results are shown below.
DSC measurement results;
Heating; Cry 120.9 ° C. (14.71 kJ / mol * ¹ ) → MI 129.7 ° C. (14.71 kJ / mol * ¹ ) → MII 158.1 ° C. (6.95 kJ / mol) → MIII 177.8 ° C. (34.49 kJ) ^{/ mol ※ 2) → MIV187.3 ℃} (34.49kJ / mol ※ 2) → Iso
* ¹ Total value of Cry → MI and MI → MII, * ² Total value of MIII → MIV and MIV → Iso.
From the results of DSC measurement, it was revealed that the liquid crystal phase was present even when the compound of the present invention was mixed to form a liquid crystal composition.

Comparative Example 1 N-methyl-4- (4′-octyloxyphenyl) -pyrazole

  4- (4′-octyloxyphenyl) -pyrazole (1.101 mmol) obtained in Example 1 and trimethyl phosphate (0.551 mmol) were reacted at 155 ° C. for 70 minutes. After cooling to room temperature, toluene was added and washed with an aqueous potassium hydroxide solution, and then the organic layer was washed with saturated brine until neutral. Next, the organic layer was dried over sodium sulfate, filtered, concentrated, and dried under reduced pressure to obtain the desired product (white silver powder, 0.611 mmol). Yield 56%.

¹ H-NMR (CDCl ₃ , Me ₄ Si) δ:
0.89 (t, J = 7.7Hz, 3H), 1.29-1.46 (m, 10H), 1.78 (m, 2H), 3.93 (s, 3H), 3.96 (t, J = 6.6Hz, 2H), 6.89 (d , J = 8.8Hz, 2H), 7.36 (d, J = 8.9Hz, 2H), 7.52 (s, 1H), 7.69 (s, 1H).
Mass spectrometry Calculated value: 286.41, experimental value: 286
From the above analysis results, it was confirmed that the obtained compound was the title compound.
DSC measurement results;
Heating; Cry 117.3 ° C. (50.24 kJ / mol) → Iso
Cooling; Iso 107.4 ° C (-35.97 kJ / mol) → Cry
Heating; Cry 117.1 ° C. (35.34 kJ / mol) → Iso
No liquid crystallinity was observed with N-methylated pyrazole derivatives.

Claims (4)

The following general formula (1)

[Wherein, X ¹ and X ² may be the same or different, and —C≡C—, —CH═CH—, —CH═N—, —OCO—, —COO—, —CONH—, —CO —, —COCH ₂ —, —OCH ₂ —, —CH ₂ NH—, —O—, — (CH ₂ ) _n — (n represents a number of 2 or more), —S— and —NH—. A linking group or a single bond is shown, Ar ¹ and Ar ² may be the same or different and each represents an aromatic ring or an aliphatic ring which may have a substituent, and m and n are each 0-2 (provided that M + n ≧ 1), and R ¹ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, a cyano group, a nitro group, or a halogen atom. ]
A pyrazole derivative represented by:   A liquid crystal compound comprising the pyrazole derivative according to claim 1.   The liquid crystal compound according to claim 2 having a hydrogen bond.   A liquid crystal composition comprising the pyrazole derivative according to claim 1.