JPH107632A - Production of 2-(4'-n-monosubstituted amino-2'-hydroxybenzoyl)benzoic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing 2-(4'-N-monosubstituted amino-2'- hydroxybenzoyl)benzoic acid useful as a synthesis intermediate for a fluoran compound for a recording material such as a pressure sensitive recording paper and heat sensitive recording paper in a simple process in high yield. SOLUTION: This method for producing 2-(4'-N-monosubstituted amino-2'- hydroxybenzoyl)benzoic acid of formula I [R1 is an alkyl, a cycloalkyl, a (p- or m-substituted) phenyl; R2 is H or an alkyl], e.g. 2-(4'-iso-pentylamino-2'- hydroxybenzoyl)benzoic acid, comprises a reaction of 3-monosubstituted aminophenyl of formula II with phthalic anhydride in the absence of solvent or in the presence of an organic solvent at 130-180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing 2- (4'-N-monosubstituted amino-2'-hydroxybenzoyl) benzoic acid. More specifically, general formula (2) useful as a synthetic intermediate of a fluoran compound for recording materials such as pressure-sensitive recording paper and heat-sensitive recording paper

[0002]

Embedded image (Wherein R 1 represents an alkyl group, a cycloalkyl group, or a phenyl group which may have a substituent at the p- or m-position, and R 2 represents a hydrogen atom or an alkyl group). The present invention relates to the production of (4'-N-monosubstituted amino-2'-hydroxybenzoyl) benzoic acid (hereinafter, referred to as monosubstituted benzophenonecarboxylic acid). Many ordinary fluoran compounds are produced using 2- (4'-N-disubstituted amino-2'-hydroxybenzoyl) benzoic acid (hereinafter referred to as disubstituted benzophenone carboxylic acid) as a raw material. Many fluoran compounds produced from acids have a characteristic hue compared to the former, and therefore have extremely high commercial value, and establishment of an industrial production method has been expected.

[0003]

2. Description of the Related Art A process for producing a disubstituted benzophenone carboxylic acid similar to the compound of the present invention is widely known as shown in the following documents and the like, and is commonly used as a process with a high yield. That is, Beilstein main part 1
4, page 675, or JP-B-46-4614, JP-B-51-12626, JP-A-5-213840, JP-A-6-49008, JP-A-6-100512, etc. A method is disclosed in which a phenol and phthalic anhydride are reacted at 70 to 120 ° C. for several hours to several tens of hours in the absence of a solvent or in the presence of an organic solvent to obtain the desired disubstituted benzophenonecarboxylic acid in good yield. In these documents, the upper limit of the reaction temperature range is 12
Some are not limited to 0 ° C. However, it is well known that the higher the temperature is, the lower the yield is due to the by-product of the rhodamine-type dye, and there is no actual case where the temperature is higher than this.

In order to test whether the above-mentioned method for producing a disubstituted benzophenonecarboxylic acid can be diverted as a method for producing a monosubstituted benzophenonecarboxylic acid, the present inventor changed the method to 3-disubstituted aminophenol as shown in the following Reference Example. The reaction was attempted in the same manner using a 3-monosubstituted aminophenol, but the main product was 3′-hydroxy-2-carboxy-benzanilide (hereinafter referred to as anilide) represented by the following general formula (3). The desired mono-substituted benzophenonecarboxylic acid could not be obtained.

[0005]

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As can be seen from these experimental facts, monosubstituted benzophenonecarboxylic acids cannot be easily obtained in the same manner as disubstituted benzophenonecarboxylic acids.
Conventionally, various alternative methods have been studied. The most typical method for producing a conventional monosubstituted benzophenone carboxylic acid is described in, for example, Beilstein's main edition, Vol. 14, 675.
Page or JP-A-49-109119, JP-A-8-1
No. 04817, a method described in the general formula (1)
Is obtained by heating and melting the monosubstituted aminophenol compound and phthalimide at 150 to 200 ° C. in the presence of substantially equimolar boric acid to form an amide compound, and then further hydrolyzing the amide compound.

[0007]

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However, this conventional method has a complicated production route and requires many devices. In addition, this method has a problem in that the boric acid waste liquid, which is known as a rice growth inhibitor, is unavoidably discharged by the adoption of the method, so that the treatment of the boric acid waste liquid imposes a heavy burden on the production side, and industrialization is difficult.
As another production method, JP-A-57-190049, JP-A-7-329416 and JP-A-8-104817 disclose 3-disubstituted aminophenol which is modified with a readily removable substituent such as benzyl to obtain a disubstituted aminophenol. After the amino group, the di-substituted benzophenone carboxylic acid is produced by reacting with the phthalic anhydride according to the general method described above, and the resulting mono-substituted benzophenone carboxylic acid is treated with a desorbing agent such as concentrated sulfuric acid to obtain the desired mono-substituted benzophenone carboxylic acid. A method of obtaining is disclosed. However, also in this method, the reaction steps were complicated, and the yield was not sufficient.

Japanese Patent Application Laid-Open No. 8-127726 discloses that
It is disclosed that mono-substituted benzophenone carboxylic acids can be obtained by the same method as the above-mentioned method for producing di-substituted benzophenone carboxylic acids only for 3-mono-substituted amino phenols in which the amino group is mono-substituted with a 2,6-di-substituted phenyl group. Have been. This is presumably because the phenyl group having a substituent at a limited specific position prevents formation of the anilide compound described above due to its steric effect.

DISCLOSURE OF THE INVENTION The present invention has been accomplished in view of the above-mentioned situation in the conventional method, and has provided a method for producing a mono-substituted benzophenonecarboxylic acid in a simple process with a high yield in a simple process. .

[0010]

That is, the present invention relates to a method of preparing a 3-monosubstituted aminophenol represented by the general formula (1) and phthalic anhydride in the absence of a solvent or in the presence of an organic solvent.
The present invention relates to a method for producing a mono-substituted benzophenonecarboxylic acid represented by the general formula (2), wherein the reaction is carried out at a temperature of up to 180 ° C.

[0011]

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One of the important requirements of the present invention is the reaction temperature. That is, as described above, if the method for producing a disubstituted benzophenonecarboxylic acid is simply diverted as a method for producing a monosubstituted benzophenonecarboxylic acid, the anilide derivative of the general formula (3) becomes a main product, and the desired monosubstituted benzophenonecarboxylic acid is converted to You can't get it. However, this anilide is isolated once, and further isolated in an organic solvent or without solvent.
The anilide is converted to the desired monosubstituted benzophenonecarboxylic acid when the temperature is maintained at a high temperature of 0 to 180 ° C., and the present invention has been achieved based on this finding.
The reaction temperature for carrying out the present invention is more preferably 135 to 160 ° C.

[0013]

When the reaction is carried out in an organic solvent, the amount of the organic solvent is suitably 0.1 to 20 parts by weight per 1 part by weight of the 3-substituted aminophenol. Specifically, benzene, toluene, ethylbenzene, xylene, cumene,
Pseudocumen, mesitylene, cymen, chlorobenzene, dichlorobenzene, nitrobenzene, chlorotoluene, bromobenzene, iodobenzene, iodotoluene, dibromobenzene, hexane, cyclohexane, methylcyclohexane, cyclohexanone, tetrachloroethane, tetrachloroethylene, biphenyl, diphenyl ether, octamethyl Trisiloxane, hexamethyldisiloxane and the like can be used alone or as a mixture.

The phthalic anhydride is preferably used in excess of the 3-monosubstituted aminophenol. The preferred amount of phthalic anhydride used is 0.7 to 2.0 mol, more preferably 0.9 to 1.2 mol per mol of 3-monosubstituted aminophenol.
Is a mole. In the reaction of phthalic anhydride with the 3-monosubstituted aminophenol, a small amount of pyridine is added,
The catalytic effect improves the yield of the desired product. Pyridine is 0.001 to 1 part by weight of 3-substituted aminophenol.
It is preferable to add in the range of 0.5 part by weight. Pyridine may have a substituent, and such examples include α-picoline, β-picoline, γ-picoline, aminopyridine, 4-dimethylaminopyridine and the like. These pyridines can be used alone or as a mixture.

JP-A-62-70350 discloses that
There is disclosed a method of obtaining a disubstituted benzophenone carboxylic acid by heating a rhodamine type dye by-produced in a reaction between a disubstituted aminophenol and phthalic anhydride with an alkali hydroxide to cause a decomposition reaction. After reacting the 3-monosubstituted aminophenol with phthalic anhydride also in the present invention,
Without isolating the monosubstituted benzophenone carboxylic acid, 1 to 10 mol of alkali hydroxide was added per 1 mol of the 3-monosubstituted aminophenol used as a starting material, and the mixture was heat-treated at 80 to 140 ° C. Decomposition of the rhodamine-type dye by-produced by the reaction between the substituted aminophenol and phthalic anhydride is measured, and this decomposition allows more monosubstituted benzophenonecarboxylic acid to be obtained.

After the alkali decomposition reaction of the rhodamine type dye, 2- (4'-N-) represented by the general formula (2) is obtained.
By purifying mono-substituted amino-2'-hydroxybenzoyl) benzoic acid as crystals of an alkali metal salt and filtering off, a purification effect can be obtained. Further, a large amount of the 3-monosubstituted aminophenol represented by the general formula (1) contained in the filtrate can be recovered by neutralization with sulfuric acid, hydrochloric acid or the like, and is economical.

The 2- (4'-N-monosubstituted amino-2'-hydroxybenzoyl) benzoic acid of the present invention is 2
-(4'-N-methylamino-2'-hydroxybenzoyl) benzoic acid, 2- (4'-N-ethylamino-2 '
-Hydroxybenzoyl) benzoic acid, 2- (4'-N-
Propylamino-2'-hydroxybenzoyl) benzoic acid, 2- (4'-N-iso-propylamino-2'-
Hydroxybenzoyl) benzoic acid, 2- (4′-N-butylamino-2′-hydroxybenzoyl) benzoic acid,
2- (4'-N-iso-butylamino-2'-hydroxybenzoyl) benzoic acid, 2- (4'-N-pentylamino-2'-hydroxybenzoyl) benzoic acid, 2-
(4′-N-iso-pentylamino-2′-hydroxybenzoyl) benzoic acid, 2- (4′-N-hexylamino-2′-hydroxybenzoyl) benzoic acid, 2-
(4′-N-octylamino-2′-hydroxybenzoyl) benzoic acid, 2- (4′-N-cyclohexylamino-2′-hydroxybenzoyl) benzoic acid, 2-
(4′-N-benzylamino-2′-hydroxybenzoyl) benzoic acid, 2- (4′-N-phenylamino-
2'-hydroxybenzoyl) benzoic acid, (4'-N-
p-tolylamino-2′-hydroxybenzoyl) benzoic acid, (4′-Nm-tolylamino-2′-hydroxybenzoyl) benzoic acid, 2- (4′-Np-chlorophenylamino-2′-hydroxybenzoyl) ) Benzoic acid, 2- (5′-methyl-4′-N-phenylamino-)
2'-hydroxybenzoyl) benzoic acid and the like.

[0018]

Next, the present invention will be described with reference to examples (parts are by weight). Example 1 3-Iso-pentylaminophenol (53.7 parts) and phthalic anhydride (66.6 parts) were reacted with o-dichlorobenzene (360 parts) at 140 ° C for 4 hours to obtain a deep reddish brown reaction solution. To this reaction solution, 500 parts of water and 100 parts of 48% sodium hydroxide were added, and the reaction product was dissolved in an aqueous layer and separated from an o-dichlorobenzene layer. 4 in the aqueous layer
After adding 150 parts of 8% sodium hydroxide and cooling to 10 ° C., the reaction product was separated as crystals of soda salt, and separated.
The obtained crystals were washed with 100 parts of a 10% aqueous sodium hydroxide solution. This soda salt was dissolved in 500 parts of water, and the pH was adjusted to 4 with dilute hydrochloric acid under stirring, and pale pink 2- (4'-
27.1 parts of iso-pentylamino-2′-hydroxybenzoyl) benzoic acid were obtained (melting point 60-80 ° C.).
The yield of the target compound relative to the starting material 3-iso-pentylaminophenol was 27.6%.

Example 2 A reaction of 53.7 parts of 3-iso-pentylaminophenol and 66.6 parts of phthalic anhydride together with 360 parts of o-dichlorobenzene at 140 ° C. for 4 hours gave a dark reddish brown reaction solution. Next, 48% sodium hydroxide 125 was added to the reaction solution.
Part and add rhodamine at 100 ° C for 1 hour,
The reaction turned from dark reddish brown to brown. 500 parts of water was added to the reaction solution, and the reaction product was dissolved in the aqueous layer and separated from the o-dichlorobenzene layer. 48% in the aqueous layer containing the reactants
After adding 150 parts of sodium hydroxide and cooling to 10 ° C., the reaction product was separated out as crystals of soda salt, separated and washed with a 10% aqueous sodium hydroxide solution.
This soda salt was dissolved in 500 parts of water, and the pH was adjusted to 4 with dilute hydrochloric acid under stirring, and pale pink 2- (4′-iso-pentylamino-2′-hydroxybenzoyl) benzoic acid 3 was added.
4.5 parts were obtained (melting point 60-80 ° C.). Starting material 3-
The yield of the desired product with respect to iso-pentylaminophenol was 35.2%. Next, 100 parts of toluene was added to the soda salt filtrate, the pH was adjusted to 7 with dilute hydrochloric acid under stirring, and the toluene layer was separated and concentrated. As a result 3-iso
-22.5 parts of pentylaminophenol could be recovered (41.9% recovery).

Example 3 Example 3 was repeated except that 53.7 parts of 3-iso-pentylaminophenol and 66.6 parts of phthalic anhydride were reacted together with 360 parts of o-dichlorobenzene, using 5 parts of pyridine. Reaction and treatment are performed in the same manner to give 2- (4′-iso
45.5 parts of -pentylamino-2'-pidroxybenzoyl) benzoic acid were obtained (melting point 60-80 ° C). 3-is
The yield of the desired product relative to o-pentylaminophenol was 46.4%.

Example 4 57 parts of 3-cyclohexylaminophenol and 46.6 parts of phthalic anhydride were reacted with 450 parts of o-dichlorobenzene at 150 ° C. for 2 hours to obtain a deep reddish brown reaction solution. Next, 125 parts of 48% sodium hydroxide was added to the reaction solution, and the reaction solution was decomposed with rhodamine at 100 ° C. for 1 hour, and the reaction solution changed from dark reddish brown to brown. 500 parts of water
The reaction product was dissolved in the aqueous layer and separated from the o-dichlorobenzene layer. To the aqueous layer in which the reaction product was dissolved, 150 parts of 48% sodium hydroxide was added, and the mixture was cooled to 10 ° C., and the reaction product was separated as soda salt crystals. The obtained crystals were separated with a 10% aqueous sodium hydroxide solution. Washed. This soda salt is dissolved in 500 parts of water and diluted with diluted hydrochloric acid to pH 4 with stirring.
To give 55.6 parts of pale pink 2- (4'-cyclohexylamino-2'-hydroxybenzoyl) benzoic acid. (Melting point: 163 to 164 ° C.) The yield of the target compound based on the starting material 3-cyclohexylaminophenol is 5
It was 4.8%. Next, toluene 1 was added to the soda salt filtrate.
After adding 00 parts and adjusting the pH to 7 with dilute hydrochloric acid under stirring,
The toluene layer was separated and concentrated to recover 15.6 parts of 3-cyclohexylaminophenol (recovery rate 27.4).
%).

Example 5 The reaction and treatment were carried out in the same manner as in Example 4 except that when reacting 57 parts of 3-cyclohexylaminophenol with 46.6 parts of phthalic anhydride together with 450 parts of o-dichlorobenzene, 5 parts of pyridine was used. To give 2- (4′-cyclohexylamino-2′-hydroxybenzoyl) benzoic acid 7
1.1 parts were obtained (melting point 163-164 ° C). The yield of the desired product relative to the starting material 3-cyclohexylaminophenol was 69.9%.

Example 6 When 129.5 parts of 3-phenylaminophenol and 124.3 parts of phthalic anhydride were reacted with 280 parts of o-dichlorobenzene, 8 parts of pyridine was added, and the mixture was reacted at 150 ° C. with 5 parts.
The reaction was carried out for an hour to obtain a dark blue-brown reaction solution. To this reaction solution, 300 parts of water and 250 parts of 48% sodium hydroxide were added, and the mixture was stirred to precipitate soda salt crystals. The crystals were separated and washed with 300 parts of acetone. This soda salt is dissolved in 1000 parts of water, and diluted with diluted hydrochloric acid to pH 4 with stirring.
To give 105.2 parts of 2- (4'-phenylamino-2'-hydroxybenzoyl) benzoic acid as red-brown crystals (melting point: 184-186 ° C). The yield of the target compound with respect to the starting material 3-phenylaminophenol was 45.1.
%Met.

Example 7 A reaction of 59.7 parts of 3-p-tolylaminophenol and 53.3 parts of phthalic anhydride together with 225 parts of o-dichlorobenzene at 150 to 155 ° C. for 3.5 hours to give a dark blue-brown reaction A liquid was obtained. To this reaction solution, 300 parts of water and 250 parts of 48% sodium hydroxide were added, and the mixture was stirred to precipitate soda salt crystals. The crystals were separated and washed with 300 parts of acetone. This soda salt was dissolved in 500 parts of water, and the pH was adjusted to 4 with dilute hydrochloric acid under stirring.
34 parts of (4′-p-tolylamino-2′-hydroxybenzoyl) benzoic acid were obtained (melting point: 189-192 ° C.).
The yield of the target compound relative to the starting material, 3-p-tolylaminophenol, was 32.7%.

Example 8 Example 7 was repeated except that 49.7 parts of pyridine were added when reacting 59.7 parts of 3-p-tolylaminophenol with 53.3 parts of phthalic anhydride together with 225 parts of o-dichlorobenzene.
The reaction and treatment were carried out in the same manner as described above to give 2- (4'-p
47.7 parts of (tolylamino-2'-hydroxybenzoyl) benzoic acid were obtained (melting point 189-192 ° C). The yield of the desired product with respect to the starting material, 3-p-tolylaminophenol, was 45.8%.

Reference Example 1 16.4 parts of 3-cyclohexylaminophenol and 13.3 parts of phthalic anhydride were added to 100 to 100 parts of toluene together with 120 parts of toluene.
When the reaction was carried out at 110 ° C., crystals precipitated during the reaction. After reacting for 2 hours, the reaction solution was cooled to room temperature and filtered to obtain 26.3 parts of colorless crystals (melting point: 168 to 170 ° C).
The yield of the above crystals relative to the starting material 3-cyclohexylaminophenol was 90.5%. As a result of structural analysis by IR and NMR, the crystalline compound was found to be N-cyclohexyl-3′hydroxy-2-carboxy-benzanilide.

REFERENCE EXAMPLE 2 19.9 parts of 3-p-tolylaminophenol and 17.8 parts of phthalic anhydride were reacted together with 120 parts of o-dichlorobenzene at 100 to 110 ° C., and crystals were precipitated during the reaction. . After reacting for 2 hours, the reaction solution is cooled to room temperature,
Filtration gave 25.3 parts of colorless crystals (mp 174-18).
3 ° C). The yield of the above crystals relative to the starting material 3-p-tolylaminophenol was 72.9%. As a result of structural analysis by IR and NMR,
-P-tolyl-3'hydroxy-2-carboxy-benzanilide was found.

REFERENCE EXAMPLE 3 "Conversion of anilide to benzophenonecarboxylic acid" 20 parts of the anilide obtained in Reference Example 1 were reacted with 100 parts of o-dichlorobenzene at 150 ° C. for 2 hours and treated in the same manner as in Example 3. And 2- (4'-cyclohexylamino-2 '
-Hydroxybenzoyl) benzoic acid (12.3 parts) was obtained.
The yield based on the anilide was 61.5%.

Application Example 1 "Synthesis of 2-methyl-6-cyclohexylamino-fluoran" 2- (4'-cyclohexylamino-2'-hydroxybenzoyl) benzoic acid 3 in 200 parts of 80% sulfuric acid
3.9 parts were melted at 20-25 ° C. Next, 14 parts of p-cresol was dissolved at 10 ° C and further reacted at 20 ° C for 20 hours. The reaction product was diluted with 1000 parts of ice water while keeping the temperature at 10 ° C. or lower, and the precipitate was separated by filtration. The filtered reaction product was added to 250 parts of toluene and 100 parts of water, and adjusted to pH 10 with sodium hydroxide under reflux. Next, separate the toluene layer,
Activated carbon (5 parts) was added, and clarification filtration was performed. To the residue obtained by concentrating the toluene layer, 200 parts of methanol was added, and the crystals were loosened well and the precipitated crystals were separated by filtration and dried at 110 ° C. overnight.
37.4 parts of pale pink crystals were obtained. Melting point 190.2-19
2.5 ° C. The yield was 91%. 2 thus obtained
-Methyl-6-cyclohexylaminofluoran develops a vivid yellow color on activated clay widely used as a developer in a pressure-sensitive copying system, and has a very high practical value.

[0030]

According to the production method of the present invention, 2- (4'-monosubstituted amino-2'-hydroxybenzoyl) benzoic acid can be obtained in good yield without using boric acid. The obtained benzophenone carboxylic acid derivative is used as a raw material of a fluoran compound having high utility value as an information recording dye.

Claims (4)

[Claims] 1. A compound of the general formula (1) (Wherein R1 represents an alkyl group, a cycloalkyl group, or a phenyl group which may have a substituent at the p- or m-position, and R2 represents a hydrogen atom or an alkyl group). The mono-substituted aminophenol and phthalic anhydride are mixed with each other in the absence of a solvent or in the presence of an organic solvent at 130 to 180.
General formula (2) characterized in that the reaction is carried out at a temperature of ℃. (Wherein R1 and R2 are the same as described above).
-N-monosubstituted amino-2'-hydroxybenzoyl)
A method for producing benzoic acid. (2) R1 in the general formulas (1) and (2) is a cyclohexyl group or a p-methylphenyl group;
The method for producing 2- (4'-N-monosubstituted amino-2'-pidroxybenzoyl) benzoic acid according to claim 1, wherein 2 is a hydrogen atom. 3. The method according to claim 1, wherein the reaction between the 3-monosubstituted aminophenol and phthalic anhydride is carried out in the presence of pyridine which may have a substituent. A method for producing -N-monosubstituted amino-2'-hydroxybenzoyl) benzoic acid. 4. The reaction of 3-monosubstituted aminophenol with phthalic anhydride without isolation of 2- (4'-N-monosubstituted amino-2'-hydroxybenzoyl) benzoic acid without isolation. An alkali hydroxide equivalent to 1 to 10 moles was added to 1 mole of the 3-monosubstituted aminophenol used as a raw material and heat-treated at 80 to 140 ° C. 3. The 2- (4'-N-monosubstituted amino-) according to claim 1 or 2, wherein decomposition of the rhodamine type dye is performed.
2′-Hydroxybenzoyl) method for producing benzoic acid.