JPH09301906A - Production of 2,3,6,7,10,11-hexahydroxytriphenylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce 2,3,6,7,10,11-hexahydroxytriphenylene in high purity. SOLUTION: This production of 2,3,6,7,10,11-hexahydroxytriphenylene comprises hydrolyzing and/or alcoholizing a carboxylic acid ester or carbonic acid ester of 2,3,6,7,10,11-hexahydroxytriphenylene.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to discotic liquid crystal mesogens (Naarmann, H., Hanack, M., Mattmer,
R., "Synthesis" 477, 1994; Henderson, P., Ringsdor
f, H., Schuhmacher, P., "Liq. Crystals" 18, 191, 199
5; Beattie, DR, Hindmarsh, P., Goodby, JW, Has
lam, SD, Richardson, RM, "J. Mater. Chem." 2,
1261, 1992; Boden, N., Bushby, RJ, Cammidge, A.
N., "J. Am. Chem. Soc." 117, 925, 1995) and the like, 2,3,6,7,10,11-hexahydrotriphenylene (hereinafter abbreviated as HHTP) useful as a raw material. Regarding manufacturing method.

[0002]

2. Description of the Related Art As a method for producing HHTP, 1,2-dialkoxybenzene is used as a starting material and anhydrous iron chloride is used.
In the presence of (III) (Naarmann, H., Hanack, M., Mattme
r, R., "Synthesis" 477, 1994; Boden, N., Borner, R.
C., Bushby, RJ, Cammidge, AN, Jesudason, M.
V., "Liq. Crystals" 15, 851, 1993) or in the presence of p-chloranil (Musgrave, OC, Webste.
r, CJ, "J. Chem. Soc." (C), 1397, 1971.) Oxidative coupling is carried out to give the trimer 2,3,6.
It is known to produce 7,10,11-hexaalkoxytriphenylene and then dealkylate this product in the presence of boron tribromide or hydrogen bromide.
However, this method cannot dealkylate all of 2,3,6,7,10,11-hexaalkoxytriphenylene, and the reaction product contains insufficiently dealkylated monoalkoxytriphenylene or dialkoxytriphenylene. Alkoxytriphenylene is mixed in several%, and it is very difficult to separate this undealkylated product from HHTP.
High-purity HHTP cannot be obtained by the above method. On the other hand, Naarmann, H. (see Synthesis, 477, 1994)
Et al. Prepared anhydrous sulfuric acid (III) chloride with 9.5 times or more its molar amount of sulfuric acid to prepare a sulfuric acid solution of iron (III) sulfate, and reacted this solution with catechol to produce HHTP iron ( II) It was reported that a complex was obtained, but there is no report that HHTP was isolated in a pure form from this complex.

[0003]

DISCLOSURE OF THE INVENTION The present invention aims to provide a method for obtaining HHTP having a higher purity than that of the conventional method as described above by using a carboxylic acid ester or a carbonic acid ester of HHTP as a raw material. Is.

[0004]

HHT proposed by the present invention
The method for producing P is characterized in that a carboxylic acid ester or a carbonic acid ester of HHTP is used as a raw material and is hydrolyzed and / or alcoholically decomposed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the carboxylic acid ester or carbonic acid ester of HHTP used as a starting material may be derived from 1,2-dialkoxybenzene, but may be derived from catechol. Those are preferable. In the present invention, the carboxylic acid ester of HHTP refers to a compound in which hydrogen of all hydroxyl groups of 2,3,6,7,10,11-hexahydroxytriphenylene is substituted with an acyl group, and the ester is Esterification reagents for obtaining include formic acid, acetic acid, purpionic acid,
Carboxylic acid such as butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, benzoic acid, toluic acid, and naphthoic acid, and halides (typically chlorides) of the above carboxylic acids, and acid anhydrides are all It can be used. However, as the carboxylic acid ester used in the present invention, the hydrogen of the hydroxyl group of HHTP is substituted with an acetyl group.
3,6,7,10,11-hexaacetoxytriphenylene is the most common. The carboxylic acid ester of HHTP can be easily obtained by reacting HHTP with a carboxylic acid or a carboxylic acid derivative (carboxylic acid halide, carboxylic acid anhydride, etc.),
As described above, HHTP is difficult to isolate and purify when produced by a conventional method. Therefore, for example, the reaction product obtained by trimerization of catechol is reduced by a reducing agent such as sodium dithionite and then reacted with a carboxylic acid or a carboxylic acid derivative, or obtained by trimerization of catechol. The reaction product can be obtained by reacting a carboxylic acid or a carboxylic acid derivative in the presence of a reducing agent such as zinc. The carboxylic acid ester of HHTP thus obtained can be easily isolated from the reaction mixture, and can also be easily purified to be highly purified. Similarly, carbonic acid ester of HHTP means 2,3,6,7,1
It means a compound in which all hydroxyl groups of 0,11-hexahydroxytriphenylene form a carbonate, and examples of the carbonic acid esterification reagent for obtaining the ester include alkyl chlorocarbonate, dialkylpyrocarbonate, diarylcarbonate and the like. Can be used. H
Carbonic acid esters of HTP include methyl carbonate, ethyl carbonate, propyl carbonate, butyl carbonate, phenyl carbonate, benzyl carbonate, etc., but the most common one is ethyl carbonate. The carbonic acid ester of HHTP can be obtained by reacting HHTP with a carbonic acid esterification reagent,
As mentioned above, it is difficult to isolate and purify HHTP. Therefore, for example, the reaction product obtained by the trimerization of catechol is reduced with a reducing agent such as sodium dithionite and then reacted with a carbonic acid esterification reagent, or the reaction product obtained by the trimerization of catechol is obtained. The product can be obtained by reacting a carbonic esterification reagent in the presence of a reducing agent such as zinc. The carbonic acid ester of HHTP thus obtained can be easily isolated from the reaction mixture as in the case of the carboxylic acid ester described above, and can also be easily purified to be highly purified.

It is generally preferred to use a catalyst for the hydrolysis and / or alcoholysis utilized in the present invention. As this catalyst, both basic catalysts and acidic catalysts can be used, and specific examples thereof are as follows:
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Potassium hydrogen carbonate, potassium cyanide, sodium borohydride, lithium aluminum hydride, ammonia,
Methylamine, triethylamine, ethanolamine,
Pyridine, sulfuric acid, hydrochloric acid and the like can be mentioned. Among these, it is preferable to use an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The amount of the catalyst used is selected in the range of 0.01 to 20 mol per mol of the starting material. If the amount of the catalyst used is too small, the yield of HHTP decreases, and if it is too large, the burden of post-treatment increases, which is not preferable. The hydrolysis reaction and / or alcohol decomposition reaction of the present invention is carried out in a reaction solvent, and water involved in hydrolysis and alcohol involved in alcohol decomposition are usually supplied to the reaction system as a reaction solvent. . However, when a reaction solvent other than water is used for hydrolysis and a reaction solvent other than alcohol is used for alcohol decomposition, water or alcohol is added in an amount of 6 to 3 per mol of the starting material.
Used in the range of 0 mol. As the alcohol involved in the alcohol decomposition, methanol, ethanol, isopropyl alcohol, etc. can be used. As the reaction solvent, water or an organic solvent which does not inhibit the hydrolysis reaction and / or the alcohol decomposition reaction intended by the present invention can be used, and the organic solvent of this kind is an alcohol such as methanol, ethanol or isopropyl alcohol. , Acetone, ketones such as methyl ethyl ketone, acetonitrile, polar solvents such as dimethylformamide, ether solvents such as tetilahydrofuran, ethyl ether, dioxane, halogenated hydrocarbon solvents such as methylene chloride, chloroform, dichloroethane, benzene, Hydrocarbon-based solvents such as toluene, xylene, and hexane, and mixed solvents thereof are included. Among them, alcohols or ether solvents are preferable, and alcohols are particularly preferable. The reaction temperature is generally -30 ° C to 150 ° C, preferably 0 ° C to 1
00 ° C, more preferably 20 ° C to 80 ° C, most preferably 30 ° C to 60 ° C. The reaction time is generally selected in the range of 1 hour to 100 hours, preferably 2 hours to 50 hours, more preferably 3 hours to 25 hours. By adjusting the reaction temperature and the reaction time as appropriate, it is possible to obtain almost 100
The hydrolysis and / or alcoholysis of the present invention can be performed at a conversion of%.

Next, from the reaction mixture obtained by hydrolysis and / or alcoholysis, H which is the target product is obtained.
Explaining the method of recovering HTP, when an acidic catalyst is used for hydrolysis and / or alcoholysis, HHTP having a purity of 90 to 99% can be recovered by filtering the reaction mixture as it is. . In the case of using a basic catalyst, for example, by mixing an aqueous hydrochloric acid solution with the reaction mixture and then filtering, a purity of 90 to 90 can be obtained as in the case of using an acidic catalyst.
99% HHTP can be recovered. When a basic catalyst such as sodium hydroxide is used for hydrolysis and / or alcoholysis, in this case, the hydrolysis and / or alcoholysis of the present invention results in the conversion of HHTP carboxylic acid ester and carbonic acid ester into HHTP. The above sodium salt is decomposed into HHTP by mixing the reaction mixture with an aqueous hydrochloric acid solution. This decomposition is exothermic, so
In order to suppress the temperature rise, it is preferable to use a relatively dilute hydrochloric acid aqueous solution. Further, when alcohol is used as a reaction solvent for hydrolysis and / or alcoholysis, the produced HHTP is soluble in alcohol and insoluble in water. Therefore, mixing with an aqueous hydrochloric acid solution is advantageous for precipitating HHTP. Is. The concentration of the hydrochloric acid aqueous solution added to the reaction mixture can be arbitrarily selected within the range of 0.1 to 12 N, preferably 1 to 6 N, and more preferably 2 to 4 N. The amount of the hydrochloric acid aqueous solution added to the reaction mixture is, by volume, 1 to 2 of the reaction mixture.
0 times, preferably 2 to 10 times, more preferably 3 to 5 times
It is chosen in the range of double. When an organic solvent that is incompatible with water or alcohol is used as a reaction solvent for hydrolysis and / or alcohol decomposition, these solvents may be distilled or extracted prior to addition of the aqueous hydrochloric acid solution. If desired, it can be removed from the reaction mixture. As mentioned above, according to the method of the present invention, HH
TP can be obtained with a purity of 90 to 99%.
The purity can be further increased by applying a known purification means such as a recrystallization method to P.

Next, a synthetic example of the carboxylic acid ester and carbonic acid ester of HHTP used as the starting material of the present invention will be shown. Synthesis Example 1 (Synthesis of acetic acid ester of HHTP) FeCl ₃ (anhydrous) was added to a 5 L separable flask.
Then, water (333 ml) was slowly added with a dropping funnel while cooling with ice. Then catechol solution (4
1 wt%, catechol: 113 g, H ₂ O: 164 g)
Was introduced. The reaction was carried out at normal pressure of 50 ° C. for 1 hour. After the reaction was completed, 2.3 L of 3N hydrochloric acid aqueous solution was added and the mixture was left standing overnight. The precipitated crude HHTP (composition: HHTP 40% by mass, iron complex 5% by mass, quinone body 55% by mass) was separated by filtration, washed with water, and then air-dried for one day in a nitrogen stream (78 g, 6).
9%). 25 g of dried crude HHTP was added to acetic anhydride (500
ml), zinc (25 g), triethylamine (20 m
1) was added, and the mixture was refluxed (130 ° C.) under atmospheric pressure at 1
After reacting for a period of time, it was filtered hot and left overnight. The generated crystals were separated by filtration, washed with acetic anhydride, acetone, and methanol, and dried to obtain 30.8 g (yield 70%) of hexaacetoxytriphenylene (hereinafter referred to as HATP) which is an acetic acid ester of HHTP. Was given. The pale yellow crystals thus obtained were dissolved in dimethylformamide (240 ml) containing 2.5% by volume of acetic anhydride, hot filtered, left to stand overnight, filtered, washed with dimethylformamide and methanol and dried. By doing, purity 9
21.6 g of 9.5% HATP (recrystallization yield 70%)
Obtained. Synthesis Example 2 (Synthesis of propionate ester of HHTP) To 25 g of crude HHTP obtained in the same manner as in Synthesis Example 1 above, propionic anhydride (500 ml), zinc (25 g) and triethylamine (30 ml) were added, and the mixture was heated at 125 ° C. for 1 hour. After reacting, hot filtration was performed and left overnight. The generated crystals were separated by filtration, washed with acetone and methanol, and dried to give 13.9 g of HHTP propionate (yield 2
7.2%) was obtained. The pale yellow crystals thus obtained are
It was dissolved in 2.5% by volume of propionic anhydride (240 ml) and hot-filtered, and after standing overnight, it was filtered again, washed with methanol, and dried to obtain HH having a purity of 99.9%.
18.7 g of TP propionate (total yield 69.
0%). Synthesis Example 3 (Synthesis of HHTP ethyl carbonate) Synthesis was carried out in the same manner as in Synthesis Example 1 described above, and further 10% Na
Crude HHTP washed with ₂ S ₂ O ₄ solution (32.4 g)
To a mixture of dichloromethane (100 ml) and ethyl chlorocarbonate (78.1 g), triethylamine (72.9 g) was added dropwise under ice cooling. After completion of dropping, the mixture was stirred at room temperature for 4 hours. A few drops of acetic acid were added to this reaction solution, 600 ml of dichloromethane was added, and the dichloromethane solution was washed twice with a separating funnel. Next, anhydrous magnesium sulfate was added thereto, and the mixture was left standing overnight, filtered, and dichloromethane in the filtrate was evaporated to give 57.7 g (76.
3%). The solid was recrystallized from 2-propanol to give 42.7 g of pure HHTP ethyl carbonate (56.
5%). The melting purity of this product was 99.6%.

[0009]

The present invention will be described in more detail with reference to the following examples, but these examples do not limit the present invention. The conversion rate to HHTP in the examples was measured by high performance liquid chromatography (HPLC). Column: Zorvax ODS 4.6 × 250 mm manufactured by DuPont, mobile phase: CH ₃ CN / H ₂ O / H ₃ PO ₄ = 60/40
/0.1 Flow rate: 1.0 ml / min Retention time: HHTP; 2.2 min HATP;
3 min HHTP propionate; 8.7 min mobile phase: CH ₃ CN / H ₂ O / H ₃ PO ₄ = 80/20
/0.1 Flow rate: 1.0 ml / min Retention time: HHTP ethyl carbonate; 8.9 min HHTP; ¹ H-NMR (400 MHz, CD ₃ OD) δ 4.85 (s, 6H, OH), 7. 74 (s, 6
H, Arom) ppm ¹³ C-NMR (100 MHz, DMSO-d ₆ ) δ 107.85, 121.92, 145.30 ppm HHTP; m. p. 326 to 334 ° C. ¹ H-NMR (400 MHz, DMSO-d ₆ ) δ 2.39 (s, 18 H, CH ₃ ), 8.66 (s,
6H, Arom) ppm ¹³ C-NMR (100 MHz, DMSO-d ₆ ) δ 20.38, 119.05, 127.19, 14
2.39,168.40 ppm HHTP propionate: m.p. p. 266-27
0 ° C. ¹ H-NMR (270 MHz, CDCl ₃ ) δ 1.32 (t, J = 7.3 Hz, 18 H, C
H ₃ ), 2.63 (q, J = 7.3 Hz, 12H, CH
₂ ), 8.09 (s, 6H, Arom) ppm ¹³ C-NMR (67.5 MHz, CDCl ₃ ) δ 9.17, 27.66, 118.12, 127.5.
2 142.19,171.55 ppm HHTP ethyl carbonate [2,3,6,7,10,
11-hexa (ethoxycarbonyloxy) triphenylene] m. p. 198 to 201 ° C. ¹ H-NMR (270 MHz, CDCl ₃ ) δ 1.44 (t, J = 7.0 Hz, 18 H, C
H ₃ ), 4.41 (q, J = 7.0 Hz, 12H, CH
₂ ), 8.07 (s, 6H, Arom) ppm ¹³ C-NMR (67.5 MHz, CDCl ₃ ) δ 14.23, 65.33, 117.85, 127.
26, 142.25, 152.60 ppm Example 1 Hexaacetoxytriphenylene (HA obtained in Synthesis Example 1)
TP) 57.7 g was suspended in 500 ml of ethanol,
When 288 ml of a 10% sodium hydroxide aqueous solution was added thereto, the reaction solution changed to dark blue. 2 at reflux temperature
After heating for an hour, the reaction solution was poured into 1 liter of water, and the pH was adjusted to 1 with hydrochloric acid. The solid content precipitated in the reaction solution was separated by filtration and dried to obtain 26.2 g of HHTP blue-gray crude crystals (yield 81%, purity 99.7%). The conversion of hydrolysis in this example was almost 100%. Example 2 Hexaacetoxytriphenylene (HA obtained in Synthesis Example 1
TP) 57.7 g, 30% sodium hydroxide aqueous solution 10
It was suspended in 0 ml and stirred at 60 ° C. for 2 hours. Then, the reaction solution was poured into 500 ml of water, and hydrochloric acid was added dropwise until the pH reached 1. The solid content precipitated in the reaction solution is filtered off,
It was dried to obtain 26.0 g of crude HHTP crystals (yield 80%, purity 99.5%). Example 3 144.2 g of hexaacetoxytriphenylene (HATP) obtained by the same method as in Synthesis Example 1 was added to 500 m of methanol.
10% sodium hydroxide aqueous solution 7
20 ml was added. After heating at reflux temperature for 2 hours, the reaction solution was poured into 3 liters of water and salting out was performed with hydrochloric acid. The precipitate was filtered off and dried to obtain 64.8 g of crude HHTP crystals (yield 80%, purity 99.6%). Example 4 66.0 g of HHTP propionate obtained by the same method as in Synthesis Example 2 was suspended in 250 ml of methanol,
To this, 360 ml of 10% aqueous sodium hydroxide solution was added. After heating at reflux temperature for 2 hours, the reaction solution was poured into 1.5 liters of water and salting out was performed with hydrochloric acid. The precipitate was filtered off and dried to give 25.9 g of crude HHTP crystals (yield 80
%, Purity 99.8%) was obtained. Example 5 2,3,6,7,10,11-hexa (ethoxycarbonyloxy) triphenylene 7.56 obtained in Synthesis Example 3
g was suspended in 50 ml of methanol, and 28.8 g of a 10% sodium hydroxide aqueous solution was added thereto, and the reaction solution instantly turned dark blue. After heating at reflux temperature for 2 hours, the reaction solution was poured into 150 ml of water and salting out was performed, and carbon dioxide was vigorously generated. The pH was adjusted to 1 and the precipitate was filtered off and dried to give crude HHTP crystals 2.6.
6 g (yield 82%, purity 99.9%) was obtained. Example 6 HHTA (144.2 g) in methanol (500 ml)
Suspended in and triethylamine (152 g) was added. After reacting for 2 hours at the reflux temperature, 3000 ml of water was added and salting out was performed with hydrochloric acid. The precipitate was filtered and dried to obtain 59.9 g of crude HHTP crystals (yield 74%, purity 99.7%). Example 7 7.53 g of 2,3,6,7,10,11-hexa (ethoxycarbonyloxy) triphenylene was suspended in methanol (50 ml), and triethylamine (7.0) was added.
When g) was added, the reaction solution immediately turned dark blue. After reacting for 2 hours at the reflux temperature, 150 ml of water was added and salting out was performed with hydrochloric acid. After the pH was adjusted to 1, the precipitate was filtered and dried to obtain 2.47 g of crude HHTP crystals (yield 7
6%, purity 99.6%) was obtained.

Claims (2)

[Claims] 1. 2,3,6,7,10,11,2,3,6,7,10,11 characterized by hydrolyzing and / or alcoholylating a carboxylic acid esterified product of 2,3,6,7,10,11-hexahydroxytriphenylene. -Method for producing hexahydroxytriphenylene. 2. A 2,3,6,7,10,11- which is characterized in that a carbonic acid ester of 2,3,6,7,10,11-hexahydroxytriphenylene is hydrolyzed and / or alcoholically decomposed. Method for producing hexahydroxytriphenylene.