JPH10324665A - Production of ester compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably producing high-purity ester compounds even in the presence of a quinone as an impurity by the esterification of a polyphenol compound in the presence of a specific compound. SOLUTION: This ester compound is obtained by the esterification of a polyphenol compound with a 3-25C carboxylic acid compound in the presence of a reducing agent. Zinc or magnesium is used as the reducing agent, the former being more preferable, at a dosage of 0.001 to 30 mols per 100 g of the polyphenol compound. A tertiary amine can be optionally used, in order to enhance the effects of the reducing agent. Particularly preferable carboxylic acids are acid halides. The ester compound can be used as a discotic, liquid crystal compound useful as a liquid crystal material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a high-purity ester compound, and more particularly to a method for producing a discotic liquid crystal compound useful as a liquid crystal material with high purity.

[0002]

2. Description of the Related Art In recent years, liquid crystal display elements have been widely used in word processors, personal computers, televisions and the like, and industrial activities such as materials and devices related thereto have been actively carried out. Active development research has also been conducted on liquid crystal compounds, which are basic materials of liquid crystal display materials, and many compounds have been developed. These compounds are being developed for use in various applications other than display devices. In addition to the rod-shaped liquid crystal compounds that have been well known and used in the past, recently, disc-shaped liquid crystal compounds,
So-called discotic liquid crystal compounds have come to the spotlight. Representative examples of discotic liquid crystal compounds include C. Destrade, Mol. Cryst. Liq. Crys
t., 71, 111 (1981) and Shunsuke Takenaka, "Liquid Crystal Chemistry", Chemistry Review, 22, 60 (1994), for example, a tolcene derivative, a triphenylene derivative, an oxyturcene derivative, a benzene derivative. And anthraquinone derivatives. Discotic liquid crystal compounds generally have a structure in which these are used as a central nucleus of a molecule and a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, or the like is radially substituted as a side chain. Discotic liquid crystal compounds are likely to be useful as electronic materials for liquid crystal display elements, optical elements, conductive films, and the like because they readily form monodomain discotic nematic phases as molecular alignment. Among them, discotic liquid crystal compounds in which a side chain is bonded to a central mother nucleus via an ester bond are particularly suitable as a material for a liquid crystal display device or the like.

[0003]

In general, when a liquid crystal is used in an electronic device or the like, the purity of the liquid crystal affects characteristics of a liquid crystal display element, an optical element, a conductive film, and the like. The discotic liquid crystal compound described above is no exception, and its properties are greatly affected by its purity. For example, when a discotic liquid crystal compound is used as a liquid crystal display device such as a liquid crystal display, specifically, as a compensation film material, the film itself is required to have no absorption. However, when impurities of the liquid crystal compound, particularly impurities derived from a quinone compound which is an oxide, are included in the material, the material has absorption on a short wavelength side in a visible light region, and significantly deteriorates performance as a compensation film. . Among the discotic liquid crystal compounds requiring high purity as described above, polyphenol compounds represented by, for example, hexahydroxyturqusene, which are the raw materials of the compounds, generally have extremely poor oxidation stability. Therefore, when a parent nucleus, for example, hexahydroxytorxene is synthesized, a quinone having a hydroxyl group oxidized is easily generated regardless of the synthesis conditions and storage conditions. Also, when performing a reaction for introducing a side chain into the mother nucleus via an ester bond, a quinone compound is easily generated as a by-product during the reaction,
It was very difficult to obtain a highly pure compound. Therefore, the present invention has been made in view of such circumstances, and its purpose is to stably convert a high-purity ester compound from a polyphenol compound into a polyphenol compound regardless of the presence or absence of a quinone derivative derived from the specific polyphenol compound. An object of the present invention is to provide a method for producing an esterified product that can be produced.

[0004]

Means for Solving the Problems In order to achieve the above object, the method for producing an esterified product of the present invention is characterized in that the method comprises the steps of:
The polyphenol compound is esterified using the carboxylic acid compound of No. 5 and a reducing agent. Further, the method for producing an esterified product of the present invention comprises esterifying a polyphenol compound and a quinone of the polyphenol compound using a carboxylic acid compound having 3 to 25 carbon atoms and a reducing agent. In the present invention, the quinone compound refers to an oxide or a partial oxide obtained by oxidizing a hydroxyl group of the polyphenol compound. The method of the present invention is characterized in that the quinone compound as an impurity is reduced, and a polyphenol compound as a raw material is esterified together with a polyphenol compound generated by the reduction to produce a high-purity ester compound. Further, the method of the present invention is suitable for producing an ester compound useful as a discotic liquid crystal compound with high purity.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polyphenol compound used in the present invention is a compound having two or more phenolic hydroxyl groups. In the present invention, a crude polyphenol compound containing a quinone compound which is an oxide of the compound as an impurity can be used as a raw material. Specific examples of polyphenol compounds include, for example, 2,3,7,8,12,13-hexahydroxyturqucene, 2,3,6,7,10,11-hexahydroxytriphenylene, 2,3,7,8 , 12,13-Hexahydroxy-5,10,15-trioxatolcene,
2,3,7,8,12,13-hexahydroxy-5,
10,15-trithia tolcene, hexahydroxybenzene, leucoquinizarin, 1,2,3,5,6,7-
Hexahydroxy-anthracene-9,10-dione,
2,3,5,6-tetrahydroxyhydroquinone and the like. Of these, 2,3,7,8,12,13-
Hexahydroxytorxene, 3,6,7,10,11
-Hexahydroxytriphenylene is preferable, and 2,3,7,8,12,13-hexahydroxytorxene is more preferable. The method for producing the polyphenol compound is not particularly limited, and the compound obtained by synthesis by a known method or a commercially available compound can be directly used in the present invention. Known methods include, for example, a method of dealkylating a corresponding alkoxy compound in the presence of boron tribromide or hydrogen bromide. Specifically, for example, when producing 2,3,7,8,12,13-hexahydroxyturqusene, 3- (3,4-
(Dialkoxyphenyl) -propionic acid is subjected to intramolecular alkylation in the presence of an acid catalyst to give dialkoxyindanone. The dialkoxy indanone is then trimerized by aldol condensation in a polyphosphate to give 2,3,3
7,8,12,13-Hexaalkoxyoxytolcene, which can be obtained by dealkylation in the presence of boron tribromide or hydrogen bromide. Also,
In the case of 2,3,6,7,10,11-hexahydroxytriphenylene, 1,2-dialkoxybenzene is converted to anhydrous iron (III) chloride (H. Naarmann, M. Hanack, R. Ma.
ttmer, Synthesis, 477, 1994, N. Boden, RCBorner,
RJBushby, ANCammidge, MVJesudason, Liq.Crys
t, 15, 851, 1993) or in the presence of p-chloranil (OCMusgrave, CJ Webster, J. Chem. Soc. (C), 1397,
1971), the 2,3,6,7,10,11-hexaalkoxytriphenylene, which is a trimer, is once formed by oxidative coupling. This product can then be prepared by dealkylation as described above. As another method for producing the triphenylene, anhydrous sulfuric acid (III) is reacted with sulfuric acid in a molar amount of 9.5-fold or more to prepare a sulfuric acid solution of iron sulfate (III), and this solution is mixed with catechol. Reaction method (H. Naarmann, M.
Hanack, R. Mattmer, Synthesis, 477, 1994). Compounds obtained by a known method as described above, for example, hexahydroxyturqusene and hexahydroxytriphenylene, do not require any particular purification or the like, and include impurities, specifically, quinones and the like in the present invention. Can be offered.

By reacting the above-mentioned polyphenol compound with a carboxylic acid compound or a reducing agent described below under various conditions or performing post-treatment, an ester compound such as an ester compound represented by the following general formulas (I) to (V) is obtained. be able to.

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Embedded image In the general formulas (I) to (V), R1, R2, R3, R
4, R5 and R6 each independently represent a hydrogen atom or -C
R represents an alkyl group having 2 to 24 carbon atoms, a cycloalkyl group, an aryl group, a substituted alkyl group, a substituted cycloalkyl group, or a substituted aryl group. Where R
Except when 1, R2, R3, R4, R5 and R6 are all hydrogen atoms. R1, R2, R3, R4, R
As more specific examples of 5 and R6,
And those represented by 0.

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Embedded image Here, C _n H _{2n + 1} represents a linear or branched alkyl group, and n is an integer of 1 to 18, preferably 3 to 14. k is 1, 2 or 3.

Embedded image Here, m is an integer of 2 to 14, preferably 2 to 8. X is H or CH ₃ .

Embedded image Here, p is an integer of 1 to 15, preferably 7 to 10.

Embedded image However, q is an integer of 2-14, preferably an integer of 2-8. Substituents exemplified in these Chemical Formulas 6 to 10 are replaced with Chemical Formula 1
R1, R2, R3, R of the general formulas (I) to (V)
In the present invention, the ester compound having 4, 4, R5 and R6 can be obtained with high purity.

Next, the carboxylic acid compound used in the present invention means an esterified product, an acid anhydride or an acid halide of a carboxylic acid having 3 to 25 carbon atoms, and among them, a halide is particularly preferable. Preferred examples of the carboxylic acid compound that can be provided in the present invention include carboxylic acid compounds corresponding to the substituents exemplified in Chemical Formulas 6 to 10. Although the amount of the carboxylic acid compound is not particularly limited, it is arbitrarily determined according to the specific example of the polyphenol compound. Hexahydroxytorxcene, hexahydroxytriphenylene, hexahydroxytrioxatruxene as a polyphenol compound,
Taking leucoquinizarin as an example, usually 1.3 to 42 mol, preferably 1.3 to 13 mol, more preferably 1.3 per 100 g of the polyphenol compound, regardless of the presence or absence of the quinone form of the polyphenol compound. ~
It is selected in the range of 8 moles. Further, taking hexahydroxybenzene as an example, irrespective of the presence or absence of the quinone form of the benzene, per 100 g, usually 2.6 to 80 mol, preferably 2.6 to 26 mol, more preferably 2.6 to 26 mol.
It is selected in the range of 16 moles. Further, in order to promote the reaction between the polyphenol compound and the carboxylic acid compound, it is desirable to use a base as an additive. As such a base, specifically, pyridine, tripropylamine, triethylamine, tributylamine,
N, N-dimethylaniline, diazabicycloundecene and the like can be mentioned. These bases are used as a reaction between a polyphenol compound present in the reaction system and a polyphenol compound produced by reduction of a quinone derivative derived from the polyphenol compound and a carboxylic acid compound, and a hydrogen halide or an acid by-produced by the reaction. It reacts with an acid compound or the like derived from an anhydride and plays a role of trapping it.

As the reducing agent used in the present invention, metals such as zinc, magnesium and aluminum, sodium hydrosulfite, hydrogen sulfide, sulfur dioxide, tin (II) chloride, hydrogen, formic acid, ascorbic acid and the like can be used. In particular, zinc and magnesium are preferred, and zinc is particularly preferred. The amount of the reducing agent to be used is generally 0.001 to 30 mol, preferably 0.01 to 10 mol, more preferably 0.05, per 100 g of the polyphenol compound.
-5 mol, most preferably 0.1-3 mol. Further, a tertiary amine may coexist in the reductive esterification reaction system in order to enhance the effect of the reducing agent. Examples of the tertiary amine include pyridine, tripropylamine, triethylamine, tributylamine, N, N-dimethylaniline, diazabicycloundecene, and the like.
The use amount of the tertiary amine is usually 5 per mole of the reducing agent.
Within a mole, preferably from 0.25 to 3 mole, more preferably from 0.4 to 2 mole, most preferably from 0.5 to 1.5 mole. When the tertiary amine is used to enhance the effect of the reducing agent and simultaneously promote the reaction between the polyphenol compound and the carboxylic acid compound as described above, the tertiary amine is usually used in an amount of 1.3 to 80 mol per 100 g of the polyphenol compound. , Preferably 3 to 30 mol.

In the method of the present invention, a solvent that does not inhibit the reductive esterification reaction and that can dissolve the ester compound as the target product can be used if necessary.
Examples of the reaction solvent include ethyl acetate, toluene, xylene, dimethylformamide, N-methylpyrrolidone, diethyl ether, tetrahydrofuran, diethylene glycol dimethyl ether (diglyme),
Examples thereof include 1,4-dioxane, methylene chloride, and mixtures thereof.

The object of the present invention is to produce a high-purity ester compound. The method comprises a reduction reaction of a quinone compound which is an impurity of the polyphenol compound, a polyphenol compound, and a polyphenol compound formed by reduction and a carboxylic acid compound. And two types of esterification reactions are carried out in the same reactor. Further, in the method of the present invention, it can be said that the two reactions proceed at the same time, or that only the reduction reaction proceeds first, and then the esterification reaction proceeds. In the latter case, the addition of the carboxylic acid compound, which is one of the raw materials, is delayed in the reactor in which the reduction reaction has proceeded. When the reduction reaction and the esterification reaction are allowed to proceed at the same time (in the case described above), the reaction temperature is usually in the range of 0 to 300 ° C, preferably 20 to 80 ° C under normal pressure. The reaction time is 0.1 to 50 hours, preferably 0.2 to 20 hours, more preferably 0.5 to 10 hours. In the case of (1), first, the reduction reaction is carried out by adding a polyphenol, a reducing agent, and optionally a base, to a reaction temperature of 0.
To 300 ° C, preferably 20 to 80 ° C, reaction time 0.5
It is desirably carried out for up to 5 hours, preferably 0.2 to 2 hours. Next, in the esterification reaction, after the reduction reaction, the carboxylic acid compound is added to the reactor, and the reaction temperature is -78.
~ 200 ° C, preferably 0 ~ 80 ° C, reaction time 0.1 ~
It is desirable to carry out for 30 hours, preferably 0.2 to 5 hours.

After completion of the reaction, (1) removal of insoluble substances such as a reducing agent, (2) removal of unreacted raw materials and salts produced as by-products, and (3) removal of the reaction solvent or the solvent used for extraction from the reaction product. The ester compound of the present invention can be isolated by performing the respective operations such as removal. These operations need not necessarily be performed in this order. The operation (1) is preferably performed, for example, by decantation or filtration. The operation (2) is specifically carried out by washing with acidic water, alkaline water and / or water. In this operation, the reaction solvent is previously removed by distillation or the like, and then extracted. It is desirable to replace with a solvent and then to carry out. The extraction solvent varies depending on the type of the ester compound to be obtained and cannot be said unconditionally. Usually, a solvent such as ethyl acetate, chloroform, carbon tetrachloride, dichloroethane, benzene, toluene and hexane is used. Examples of the acidic water used for washing include aqueous solutions of hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, and the like, and examples of the alkaline water include aqueous solutions of sodium hydrogen carbonate, sodium carbonate, potassium carbonate, and the like. Further, the operation (2) can be carried out by reprecipitation using a solvent in which the raw materials and by-products are soluble and the target product is insoluble. The reprecipitation solvent varies depending on the solubility of the obtained ester compound, but examples include water, methanol, ethanol, dioxane, diethyl ether and the like. Further (3)
The operation is usually carried out by distillation, but before and after this operation, a higher purity ester compound is obtained by performing an adsorption treatment on the activated clay, silica, alumina or silica-alumina with a trace amount of a residual carboxylic acid compound. Can be obtained. Then, the ester compound thus isolated has a sufficiently high purity, but the purity can be further increased by performing a recrystallization treatment or the like. Examples of the solvent used for recrystallization include benzene, toluene, isopropyl alcohol, ethanol, methanol, diethyl ether, amyl acetate, water and the like.

[0012]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but these Examples do not limit the present invention.

Synthesis Example 1 In a 5 L three-necked flask equipped with a stirrer and a reflux condenser, 3
-(3,4-dimethoxyphenyl) propionic acid 300
g and polyphosphoric acid (1500 g) under nitrogen atmosphere.
The reaction was performed at 65 ° C. for 30 minutes. After the reaction was cooled, 2000 mL of deionized water was gradually added. After stirring at room temperature for 2 hours, the contents of the flask were transferred to a 5 L separating funnel, and extraction was performed six times with 600 mL of chloroform. The chloroform extract was washed with a saturated aqueous solution of sodium hydrogen carbonate, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated on a rotary evaporator to give 5,6-dimethoxyindanone-
1170 g were obtained. 170 g of the obtained 5,6-dimethoxyindanone-1 and 850 g of ethyl polyphosphate were placed in a 3 L three-necked flask equipped with a stirrer and a reflux condenser, and heated to 140 ° C. for 2 hours while stirring under a nitrogen atmosphere. . After completion of the reaction, 1 L of ethanol was gradually added while cooling the flask with ice. After stirring at room temperature for 1 hour, the precipitate was collected by suction filtration. After washing this collected material with acetone, it was dried overnight in a vacuum dryer at 50 ° C.,
140 g of crude crystals of 2,3,7,8,12,13-hexamethoxytorxene were obtained. The obtained crude crystals were recrystallized from dimethylformamide solvent at a recovery of 99%. 2,3,7,8,12,13- obtained in a 1 L three-necked flask equipped with a stirrer containing 400 mL of toluene and a reflux condenser.
40.0 g of hexamethoxyturqusene was added and suspended, and 187 g of boron tribromide was successively added while stirring and cooling with ice. Then the temperature of the flask was gradually increased from 60 ° C to 120 ° C.
And then reacted at the same temperature for 2 hours. Hydrogen bromide and the like generated on the way were absorbed in a trap containing an aqueous alkali solution. After the reaction, cool the flask to room temperature,
200 mL of methanol was gradually added. At this time, hydrogen bromide, methyl bromide, methyl borate, etc. generated in large amounts are -7
Recovery treatment was performed using a trap cooled to 8 ° C., an alkali trap, or the like. The volatiles were then removed at 60 ° C. under high vacuum,
25.3 g of black crude crystals of 2,3,7,8,12,13-hexahydroxyturqusene were obtained. The content of the quinone compound contained in the crude crystal was determined by H-NMR analysis, which revealed that the quinone structure contained 17%. When a part of the obtained crude crystal was left in the air, it was immediately oxidized and generated heat.

Synthesis Example 2 Ferric sulfate hexahydrate 4 was placed in an ice-cooled 2 L three-necked flask.
60 g and 200 mL of ion-exchanged water are added, and after dissolution,
59.0 g of 1,2-dimethoxybenzene were added. Thereafter, 900 mL of concentrated sulfuric acid was gradually added under water cooling. 2
After 4 hours, the mixture was gradually poured into 10 L of ice water, and after 5 hours, the reaction mixture was filtered to obtain 50.1 g of crude crystals of 2,3,6,7,10,11-hexamethoxytriphenylene. Stirrer containing 900 mL of toluene, 3 L with reflux condenser
2,3,6,7,10,11 obtained in a three-necked flask
50.1 g of crude crystals of hexamethoxytriphenylene were added and suspended, and boron tribromide 3 was added thereto while stirring and cooling with ice.
00 g was added slowly. Then, the temperature of the flask was gradually raised from 60 ° C. to 120 ° C., and after the temperature was raised, a reaction was performed at the same temperature for 2 hours. Hydrogen bromide and the like generated on the way were absorbed in a trap containing an aqueous alkali solution. After completion of the reaction, the flask was cooled to room temperature, and 200 mL of methanol was gradually added.
At this time, a large amount of hydrogen bromide, methyl bromide, methyl borate and the like generated and recovered were collected by a trap cooled to -78 ° C, an alkali trap or the like. Then, volatile components were removed at 60 ° C. under a high vacuum, and the mixture was washed with a mixed solvent of acetonitrile and dichloromethane to obtain 30.1 g of crude crystals of 2,3,6,7,10,11-hexahydroxytriphenylene. H-NMR analysis of the crude crystal showed that the quinone structure was 1
5% was included.

Synthesis Example 3 2,3,7,8,12,13-hexamethoxy-5,1
40.0 g of 0,15-trioxatruxene was reacted with 283 g of boron tribromide in the same manner as in Synthesis Examples 1 and 2, and 2,3,7,8,12,13-hexahydroxy-5,10, Crude crystal of 15-trioxatorcene 3
8.2 g were obtained. H-NMR analysis of the crude crystals revealed that they contained 16% of a quinone compound.

Synthesis Example 4 In a 1 L three-necked flask, p-hydroxybenzoic acid 66 was added.
g, 8-bromooctane 114 g, potassium carbonate 82 g
And 400 mL of N, N-dimethylformamide were added and stirred at 120 ° C. for 4 hours. After cooling after stirring, the reaction mixture was poured into 1 L of water, extracted with 1 L of ethyl acetate,
Washed twice with 300 mL of water. Then, after drying over anhydrous magnesium sulfate, filtration was performed. After the solvent was concentrated under reduced pressure, it was dissolved in 200 mL of methanol, and potassium hydroxide 3
40 mL of a 3 g methanol solution was gradually added dropwise, and the mixture was heated under reflux for 2 hours. The crystals formed after cooling after reflux were filtered and washed with water. The filtrate was dried to obtain 115 g of 4-octyloxybenzoic acid. 23 g of the obtained 4-octyloxybenzoic acid and 25 mL of thionyl chloride were placed in a 300 mL three-necked flask, and reacted by heating under reflux for 2 hours. After completion of the reaction, excess thionyl chloride was distilled off under reduced pressure, then dissolved in 100 mL of ethyl acetate, and washed three times with 100 mL of a cooled saturated aqueous solution of sodium hydrogen carbonate.
The solvent was distilled off, and the residue was distilled under a high vacuum to obtain 22.5 g of 4-octyloxybenzoic acid chloride.

Synthesis Example 5 Using 20.8 g of 4-pentyloxybenzoic acid and 30 mL of thionyl chloride, the reaction and treatment were carried out in the same manner as in Synthesis Example 4 to obtain 20.5 g of 4-pentyloxybenzoic acid chloride. Was.

Synthesis Example 6 Using 22.2 g of 4-hexyloxybenzoic acid and 30 mL of thionyl chloride, the reaction and treatment were carried out in the same manner as in Synthesis Example 4 to obtain 21.5 g of 4-hexyloxybenzoic acid chloride. Was.

Synthesis Example 7 Using 23.2 g of 4-heptyloxybenzoic acid and 30 mL of thionyl chloride, the reaction and treatment were carried out in the same manner as in Synthesis Example 4 to obtain 22.3 g of 4-heptyloxybenzoic acid chloride. Was.

Synthesis Example 8 Using 29.2 g of 4-undecanyloxybenzoic acid and 30 mL of thionyl chloride, the reaction and treatment were carried out in the same manner as in Synthesis Example 4 to obtain 29.4 g of 4-undecanylbenzoic acid chloride. Obtained.

Synthesis Example 9 In a 500 mL three-necked flask, 33 g of ethyl p-hydroxybenzoate and 5-bromopentyl vinyl ether 58 were added.
g, 42 g of potassium carbonate and 200 mL of N, N-dimethylacetamide were added and stirred at 120 ° C. for 5 hours.
After stirring and cooling, the reaction mixture was poured into 1 L of water,
Extracted with mL of ethyl acetate and washed twice with 100 mL of water. After drying over anhydrous magnesium sulfate, filtration was performed.
After concentrating the solvent under reduced pressure, it was dissolved in 300 mL of ethylene glycol, 30 mL of an aqueous solution of 16.8 g of potassium hydroxide was gradually added dropwise, and the mixture was heated with stirring at 130 ° C. for 2 hours. After stirring and cooling, the resulting crystals were filtered off and dissolved in 2 L of water. 50 mL of concentrated hydrochloric acid was added, and the precipitated crystals were filtered under reduced pressure and washed with water. The crystals were dried to obtain 55 g of 4- (5-vinyloxypentyloxy) benzoic acid. 500m
25 g of the obtained 4- (5-vinyloxypentyloxy) benzoic acid and thionyl chloride 4
0 mL was added, and the mixture was heated and refluxed for 2 hours to react. After completion of the reaction, excess thionyl chloride was distilled off under reduced pressure, and the residue was washed with 200 mL of hexane to obtain 26.0 g of 4- (5-vinyloxypentyloxy) benzoic acid chloride.

Synthesis Example 10 In a 1 L three-necked flask, 66 g of ethyl p-hydroxybenzoate, 108 g of 6-bromohexanol, 82 g of potassium carbonate and 400 m of N, N-dimethylformamide were placed.
L was added and stirred at 120 ° C. for 5 hours. After stirring and cooling, the reaction mixture was poured into 1 L of water, extracted with 1 L of ethyl acetate, and washed twice with 200 mL of water. After drying over anhydrous magnesium sulfate, filtration was performed. After the solvent was concentrated under reduced pressure, it was dissolved in 300 mL of methanol, 80 mL of a methanol solution of 34 g of potassium hydroxide was gradually added dropwise, and the mixture was heated under reflux for 2 hours. The crystals formed after cooling after reflux were filtered off and the crystals were dissolved in 1 L of water. 70 mL of concentrated hydrochloric acid was added, and the precipitated crystals were filtered under reduced pressure and washed with ion-exchanged water. The crystals were dried to obtain 95.3 g of 4- (6-hydroxyhexyloxy) benzoic acid. 300m with stirrer and reflux condenser
An L three-necked flask was charged with 23.8 g of the obtained 4- (6-hydroxyhexyloxy) benzoic acid and dioxane 10
After adding 0 mL and 14.5 g of N, N-dimethylaniline, the temperature was raised to 50 ° C., and a solution of 10.9 g of acrylic acid chloride and 50 mL of dioxane was successively added over 30 minutes while stirring. After the addition, the mixture was further heated and stirred at 50 ° C. for 2 hours, and then the reaction solution was poured into 1 L of ion-exchanged water to precipitate crystals. After filtering this precipitate, hexane 2
After washing with 00 mL and drying, 25.0 g of 4- (6-acryloyloxyhexyloxy) benzoic acid was obtained. 500
25.0 g of the obtained 4- (6-acryloyloxyhexyloxy) benzoic acid and 50 mL of thionyl chloride were placed in a mL three-necked flask, and the mixture was heated and refluxed for 2 hours to react. After the completion of the reaction, excess thionyl chloride was distilled off under reduced pressure, washed with 200 mL of hexane, and dried to obtain 25.3 g of 4- (6-acryloylhexyloxy) benzoic acid chloride.

Example 1 500 mL of tetrahydrofuran, 5 of triethylamine
To a 2 L three-necked flask containing 0.0 g and 5.0 g of zinc powder, 20.0 g of the black crude crystals of hexahydroxyturqusene obtained in Synthesis Example 1 was added, and the mixture was stirred under heating and reflux for 1 hour. Next, a solution composed of 106.2 g of 4-heptyloxybenzoic acid chloride obtained in Synthesis Example 7 and 100 mL of tetrahydrofuran was sequentially dropped over 30 minutes,
The mixture was stirred and reacted for 1 hour under reflux. After the reaction, the precipitate and the zinc powder were filtered, and the filtrate was dissolved in ethyl acetate and filtered again. After concentrating the filtrate, it was purified using silica gel column chromatography to obtain white 2,2.
55.9 g of 3,7,8,12,13-hexa (4-pentyloxybenzoyloxy) torxene was obtained (purity 99.6%). Next, with respect to the obtained product, HN
As a result of MR analysis, it was confirmed that there was no absorption due to the quinone compound, and that all the hydroxyl groups of the raw material were substituted with 4-pentyloxybenzoyloxy groups. Also,
When the phase transition temperature of the obtained compound was measured by observation with a polarizing microscope, it was found to be crystalline phase -272 ° C-discotic nematic phase-351 ° C or higher-isotropic phase.

Example 2 500 mL of tetrahydrofuran, 5 of triethylamine
To a 2 L three-necked flask containing 0.0 g and 5.0 g of zinc powder, 20.0 g of the crude crystal of hexahydroxyturqusene synthesized in Synthesis Example 1 was added, and the mixture was stirred under heating and reflux for 1 hour. Thereafter, 4- (6-acryloyloxyhexyloxy) benzoic acid chloride 12 obtained in Synthesis Example 10 was obtained.
A solution composed of 8.7 g and 130 mL of tetrahydrofuran was sequentially added dropwise over 30 minutes, and the mixture was stirred and reacted for 1 hour under reflux. After completion of the reaction, the zinc powder was filtered, then poured into 1 L of ice water, and the precipitated crystals were filtered by suction, washed with hexane, dried, and purified using silica gel column chromatography to give white 2,3,7,8. , 12,13-Hexa (4- (6-acryloyloxyhexyloxy) benzoyloxy) torxene 55.0 g (purity)
99.8%).

Example 3 500 mL of tetrahydrofuran, 5 of triethylamine
To a 2 L three-necked flask containing 0.0 g and 5.0 g of zinc powder was added 20.0 g of the crude crystal of hexahydroxyturqusene obtained in Synthesis Example 1, and the mixture was stirred under heating and reflux for 1 hour. Thereafter, a solution composed of 111.0 g of 4- (5-vinyloxypentyloxy) benzoic acid chloride obtained in Synthesis Example 9 and 100 mL of tetrahydrofuran was successively added dropwise over 30 minutes, and the mixture was stirred and reacted under heating and reflux for 1 hour. Was. After completion of the reaction, the zinc powder was filtered, then poured into 1 L of methanol, and the precipitated crystals were filtered by suction, washed with methanol, dried, and purified by silica gel column chromatography to give white 2,3,7,8. , 12,13-Hexa (4- (5-vinyloxypentyloxy) benzoyloxy) torxene 49.5 g (purity 9)
9.5%).

Example 4 500 mL of tetrahydrofuran, 5 of triethylamine
To a 2 L three-necked flask containing 0.0 g and 5.0 g of zinc powder, 20.0 g of the crude crystal of hexahydroxytriphenylene obtained in Synthesis Example 2 was added, and the mixture was stirred under heating and reflux for 1 hour. Next, a solution composed of 112.3 g of 4-pentyloxybenzoic acid chloride obtained in Synthesis Example 5 and 100 mL of tetrahydrofuran was successively added dropwise over 30 minutes, and reacted by stirring under heating and refluxing for 1 hour. After the reaction, the precipitate and the zinc powder were filtered, and the filtrate was dissolved in ethyl acetate and filtered again. After the filtrate was concentrated, it was purified using silica gel column chromatography to give white 2,3,3.
45.1 g of 6,7,10,11-hexa (4-pentyloxybenzoyloxy) triphenylene was obtained (purity: 99.7%). H-NMR analysis of this crystal showed no absorption derived from the quinone form.

Example 5 500 mL of tetrahydrofuran, 5 of triethylamine
To a 2 L three-necked flask containing 0.0 g and 5.0 g of zinc powder, 20.0 g of the crude crystal of hexahydroxytrioxatolcene obtained in Synthesis Example 3 was added, and then heated under reflux for 1 hour.
Stirred for hours. Next, a solution composed of 94.5 g of 4-octyloxybenzoic acid chloride obtained in Synthesis Example 4 and 100 mL of tetrahydrofuran was successively added dropwise over 30 minutes, and reacted by stirring for 1 hour while heating under reflux. After the reaction, the precipitate and the zinc powder were filtered, and the filtrate was dissolved in ethyl acetate and filtered again. The filtrate was concentrated and then purified using silica gel column chromatography to give white 2,3,7,8,12,13-hexa (4-octyloxybenzoyloxy) -5,10,15-trioxatolcene 51. 6 g were obtained (purity 99.6%). H-NMR analysis of this crystal showed that no absorption derived from the quinone structure was observed.

Example 6 500 mL of tetrahydrofuran, 5 of triethylamine
After adding 3.0 g of 2,3,5,6-tetrahydroxyhydroquinone and 7.0 g of hexahydroxybenzene to a 2 L three-necked flask containing 0.0 g and 5.0 g of zinc powder, the mixture was stirred for 1 hour under reflux with heating. . Immediately after the start of stirring, the color of the system was brown, but the color became lighter with heating and stirring.
Thereafter, 221.3 g of 4-hexyloxybenzoic acid chloride obtained in Synthesis Example 6 and 200 parts of tetrahydrofuran 200
A solution consisting of mL was successively added dropwise over 30 minutes, and the mixture was stirred and reacted for 1 hour under reflux. After the reaction, the precipitate and the zinc powder were filtered, and the filtrate was dissolved in ethyl acetate and filtered again. The filtrate was concentrated and then purified using silica gel column chromatography to obtain white hexa (4-
Hexyloxybenzoyloxy) benzene 43.3 g
(Purity 99.8%). H-NMR analysis of this crystal showed that no absorption derived from the quinone structure was observed.

Example 7 300 mL of tetrahydrofuran, 5 of triethylamine
15.0 g of leucoquinizarin was added to a 1 L three-necked flask containing 0.0 g and 5.0 g of zinc powder, and the mixture was stirred under heating and reflux for 1 hour. Next, 28.7 g of 4-pentyloxybenzoic acid chloride obtained in Synthesis Example 5 and 4-undecanyloxybenzoic acid chloride 3 obtained in Synthesis Example 8
A solution consisting of 9.4 and 100 mL of tetrahydrofuran was sequentially added dropwise over 30 minutes, and the mixture was reacted by stirring for 1 hour while heating under reflux. After the reaction, the precipitate and the zinc powder were filtered, and the filtrate was dissolved in ethyl acetate and filtered again. The filtrate was concentrated and then purified using silica gel column chromatography to obtain 36.2 g of white di (4-pentyloxybenzoyloxy) and di (4-undecanyloxybenzoyloxy) leucoquinizarin (99.
5%). H-NMR analysis of this crystal showed that no absorption derived from the quinone structure was observed.

[0030]

According to the present invention, even when a polyphenol compound containing a quinone compound as an impurity is used or in a situation where it must be used, the quinone compound is reduced to produce a polyphenol compound, and this polyphenol compound is produced. Since the compound is esterified with the raw material polyphenol compound, a desired ester compound, specifically, a discotic liquid crystal compound useful as a liquid crystal material can be produced with high purity and at low cost. When the thus obtained discotic liquid crystal compound is used as an electronic material for, for example, a liquid crystal display device, it becomes possible to obtain the device having excellent liquid crystallinity and transparency.

Continued on the front page (72) Inventor Shinichi Komatsu 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Nippon Oil & Oil Co., Ltd. Central Research Laboratory

Claims (2)

[Claims] 1. A method for producing an ester compound, comprising esterifying a polyphenol compound using a carboxylic acid compound having 3 to 25 carbon atoms and a reducing agent. 2. A method for producing an ester compound, comprising esterifying a polyphenol compound and a quinone of the polyphenol compound using a carboxylic acid compound having 3 to 25 carbon atoms and a reducing agent.