JP3159471B2 - Method for producing salicylic acid derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a salicylic acid derivative which is useful as an intermediate of a developer for pressure-sensitive copying paper or as a developer for thermal paper.

[0002]

2. Description of the Related Art Heretofore, as a method for producing a salicylic acid derivative, there has been known a method for producing a salicylic acid derivative from a corresponding substituted phenol and carbon dioxide by a Kolbe-Schmidt reaction (Japanese Patent Publication No. Sho 51-151).
25174) are known. For example, 3-alkyl-
5-Aralkylsalicylic acid derivative, 3-cyclohexyl-5-α, α-dimethylbenzylsalicylic acid is o-
Cyclohexylphenol and α-methylstyrene are reacted in the presence of an acid catalyst to obtain 2-cyclohexyl-
It is produced by performing a Kolbe-Schmidt reaction using 4-α, α-dimethylbenzylphenol.
In this case, since the reaction for introducing a carboxyl group is performed at a high temperature and a high pressure, a pressure-resistant reactor is required, and there is a disadvantage that the reaction is generally expensive. On the other hand, some alkylation reactions of salicylic acid are also known. For example, a method of reacting salicylic acid with isobutanol to obtain tert-butylsalicylic acid (“Jikken Kagaku Koza”, Vol. 18, p. 30 (1950) Maruzen),
One mole of salicylic acid is reacted with two moles of 1-phenylethanol to give 5- [α-methyl-4 ′-(α-methylbenzyl) -benzyl] salicylic acid and / or 3,5-di (α-methylbenzyl) salicylic acid (JP-A-61-100493, 62-96449) and the like are known.

Generally, a salicylic acid compound as a developer for pressure-sensitive paper and heat-sensitive paper is excellent in clarity of a color image and storage stability. On the other hand, pressure-sensitive paper has poor water resistance, such as a delayed generation rate due to lack of compatibility with capsule oil in which a colorless dye is dissolved, and poor water resistance, such as the disappearance of a color image with water, to compensate for these drawbacks. Therefore, various attempts have been made. For example, a method of introducing an aromatic substituent or the like into a salicylic acid skeleton to make up for the above-mentioned disadvantage has been frequently used. In the method of introducing such a substituent, a method using phenols as a starting material is typical as described above. An object of the present invention is to provide a novel method for producing a high-purity 3-alkyl-5-benzylsalicylic acid derivative by a very easy reaction operation in a high yield.

[0003]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems. As a result, a method for producing a salicylic acid derivative capable of selectively introducing various benzyl groups at the 5-position of salicylic acid and suppressing other side reactions such as dimerization of a benzyl compound and formation of a benzyl condensate is found. The present invention has been completed. That is, the present invention
A salicylic acid compound represented by the general formula (I):

[0004]

Embedded image (Wherein R ₁ represents an alkyl group or a cycloalkyl group having 1 to 12 carbon atoms) Benzyl compounds represented by the general formula (II) or (III)

[0005]

Embedded image (Wherein, R ₂ and R ₃ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aralkyl group, an aryl group or a cycloalkyl group, and R ₄ represents a hydrogen atom or a C 1 to C ₄ (Indicating a lower alkyl group) in the presence of an aluminum chloride catalyst.

[0006]

Embedded image (Wherein, R ₁ represents an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group, and R ₂ and R ₃ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aralkyl group, an aryl group or A cycloalkyl group).

The salicylic acid compound used in the present invention is represented by the general formula (I), wherein R ₁ represents an alkyl group or a cycloalkyl group. Specific salicylic acid compounds include 3-methylsalicylic acid, 3-ethylsalicylic acid,
-Isopropylsalicylic acid, 3-sec-butylsalicylic acid, 3-tert-butylsalicylic acid, 3-cyclohexylsalicylic acid, 3-nonylsalicylic acid, and the like. The starting benzyl alcohols, benzyl alkyl ethers and dibenzyl ethers represented by the formulas (II) and (III) used in the present invention have 1 to 12 carbon atoms having no substituent or a substituent on the benzene nucleus. It is a compound having at least one alkyl group, aralkyl group, aryl group, cycloalkyl group or halogen atom such as chlorine, bromine or fluorine at the ortho, meta or para position. The alkyl group in the benzyl alkyl ethers is a lower alkyl group having 1 to 4 carbon atoms. When the number of carbon atoms is 4 or less, the reaction is fast, and the esterification reaction does not occur, and the desired product is easily obtained. In addition, when the number of carbon atoms is 4, that is, when a butyl group is used, the reaction of the tert-butyl group tends to be slow.

The benzyl alcohol used in the present invention includes benzyl alcohol, o-methylbenzyl alcohol, m-methylbenzyl alcohol, p-methylbenzyl alcohol, o-ethylbenzyl alcohol and m-methylbenzyl alcohol.
Ethylbenzyl alcohol, p-ethylbenzyl alcohol, o-isopropylbenzyl alcohol, pn-propylbenzyl alcohol, p-tert-butylbenzyl alcohol, p-nonylbenzyl alcohol, o-phenylbenzyl alcohol, p-cyclohexylbenzyl alcohol, p- (benzyl) benzyl alcohol,
2,3-dimethylbenzyl alcohol, 2,4-dimethylbenzyl alcohol, 2,5-dimethylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 3,4-dimethylbenzyl alcohol, 3,5-dimethylbenzyl alcohol, 2, 4-diethylbenzyl alcohol, 3-methyl-4-ethylbenzyl alcohol, 2,5- (dimethylbenzyl) benzyl alcohol, p-chlorobenzyl alcohol, o-chlorobenzyl alcohol, p-bromobenzyl alcohol, m-fluorobenzyl alcohol And the like, but are not limited thereto.

The benzyl alkyl ethers include benzyl methyl ether, benzyl ethyl ether, benzyl isopropyl ether, benzyl n-butyl ether, o-methyl benzyl methyl ether, o-methyl benzyl ethyl ether, o-methyl benzyl isobutyl ether, m -Methylbenzyl methyl ether, m-
Methyl benzyl ethyl ether, m-methyl benzyl isopropyl ether, o-ethyl benzyl methyl ether, o-ethyl benzyl ethyl ether, o-ethyl benzyl isopropyl ether, p-ethyl benzyl methyl ether, p-ethyl benzyl ethyl ether, p-
Ethyl benzyl isopropyl ether, p-ethyl benzyl-n-butyl ether, o-isopropyl benzyl ethyl ether, p-isopropyl benzyl ethyl ether, pn-propyl benzyl ethyl ether, p-te
rt-butylbenzylethyl ether, p-tert-butylbenzylisopropyl ether, p-tert-octylbenzylethyl ether, p-nonylbenzylmethylether, p-dodecylbenzylmethylether, p-phenylbenzylmethylether, o-phenylbenzyl Isopropyl ether, p-cyclohexylbenzyl ethyl ether, 2,3-dimethylbenzyl methyl ether,
2,4-dimethylbenzyl methyl ether, 2,5-dimethylbenzyl methyl ether, 2,6-dimethylbenzyl methyl ether, 3,4-dimethylbenzyl methyl ether, 3,5-dimethylbenzyl methyl ether, 2,4-diethyl Benzyl methyl ether, 3,4-dimethylbenzyl ethyl ether, 3,5-dimethylbenzyl ethyl ether, 2,3-dimethylbenzyl isopropyl ether,
2,4-dimethylbenzyl-n-propyl ether, 3,4-
Dimethylbenzyl-n-butyl ether, 2,4-dimethylbenzyl-sec-butyl ether, 3,5-dimethylbenzyl-n-amyl ether, 2,4-diethylbenzylethyl ether, 3,5-diethylbenzylisopropyl ether, 2, 3-diethylbenzyl-n-butyl ether,
2,4-diisopropylbenzyl methyl ether, 3,5-
Diisopropylbenzyl ethyl ether, 3-methyl-
4-ethylbenzyl methyl ether, 3-methyl-5
tert-butylbenzyl methyl ether, p-methylbenzylmethyl ether, p-methylbenzylethyl ether, p-methylbenzyl-n-propyl ether, p-methylbenzylisopropyl ether, p-methylbenzyl-n-butyl ether, p-methyl Benzyl-sec-butyl ether, p-methylbenzyl isobutyl ether, p-chlorobenzyl methyl ether, p-fluorobenzyl isopropyl ether, o-bromobenzyl methyl ether, m-bromobenzyl methyl ether, and the like, but are not limited thereto. Not something.

The dibenzyl ethers include dibenzyl ether, di (o-methylbenzyl) ether,
(M-methylbenzyl) ether, di (p-methylbenzyl) ether, di (o-ethylbenzyl) ether,
Di (m-ethylbenzyl) ether, di (p-ethylbenzyl) ether, di (o-isopropylbenzyl) ether, di (pn-propylbenzyl) ether, di (p-tert-butylbenzyl) ether, (P-nonylbenzyl) ether, di (o-phenylbenzyl) ether, di (p-cyclohexylbenzyl) ether,
Di [p- (benzyl) benzyl] ether, di (2,3-dimethylbenzyl) ether, di (2,4-dimethylbenzyl) ether, di (2,5-dimethylbenzyl) ether, di (2,6- Dimethylbenzyl) ether, di (3,4
-Dimethylbenzyl) ether, di (3,5-dimethylbenzyl) ether, di (2,4-diethylbenzyl) ether, di (3-methyl-4-ethylbenzyl) ether, di [2,5- (dimethylbenzyl) ) Benzyl] ether, di (p-chlorobenzyl) ether, di (o-chlorobenzyl) ether and the like, but are not limited thereto.

The amounts of these various benzyl compounds used are as follows:
The amount is 1 to 1.5 mol for benzyl alcohols or benzyl alkyl ethers and 0.5 to 0.75 mol for dibenzyl ethers per mol of salicylic acid. Aluminum chloride used as a catalyst may be anhydrous or one having water of crystallization, and the amount used is 0.02 to 50 mol% based on salicylic acid. Preferably in consideration of economy.
It is in the range of 1 to 10 mol%. The reaction temperature is in the range of 50 to 180 ° C, preferably 70 to 160 ° C. The reaction time is between 1 and 20 hours. In the reaction of the present invention, a solvent may be used if necessary. Examples of the solvent include those inert to the reaction, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; and halogenated hydrocarbons such as 1,2-dichloroethane, 1,1,2-trichloroethane, and monochlorobenzene. And organic acids such as acetic acid and propionic acid. When these solvents are used, the content is preferably 30 volumes / weight or less in consideration of the economy of the raw materials.

A general method of practicing the present invention is as follows:
A predetermined amount of salicylic acid, a benzyl compound, and a catalyst may be simultaneously placed in a reactor, and the temperature may be raised and reacted at a predetermined temperature, or the reaction may be performed while dropping the benzyl compound into a reaction solution. Water or alcohol generated as the reaction proceeds is trapped outside the system. If necessary, a trace amount of water or alcohol remaining in the system is removed from the system with nitrogen.

After completion of the reaction, if crystals have precipitated, they can be isolated as crystals. When it is in a dissolved state, the solvent can be distilled off and recrystallized with an appropriate recrystallization solvent to obtain crystals. The progress of the reaction and the purity of the isolated product can be determined by analysis using high performance liquid chromatography or the like.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Example 1 15.2 g (0.1 mol) of 3-methylsalicylic acid, 13.4 g (0.11 mol) of benzyl methyl ether and aluminum chloride
0.6 g is charged into a glass reactor, and the reaction temperature is 130-140.
A condensation reaction was performed at 6 ° C. for 6 hours. On the way, generated methanol was removed from the system by passing nitrogen gas through. After the reaction,
After cooling to 90 ° C., adding 30 ml of toluene and then cooling, crystals were precipitated. This was filtered to obtain crude crystals, which were further recrystallized with toluene to obtain 17.1 g of white crystals of 3-methyl-5-benzylsalicylic acid (yield 71%). 156 ° C
～159 ° C. Elemental analysis (C ₁₅ H ₁₄ 0 _{3) ^{1 H-NMR (CDCl 3)}} 2.15 (s, 3H), 3.89 (s, 2H), 7.3 (m, 8H), 10.5 (s, 1H)

Example 2 A glass reactor was charged with 15.2 g (0.1 mol) of 3-methylsalicylic acid, 14.9 g (0.11 mol) of p-methylbenzyl methyl ether and 0.6 g of aluminum chloride.
The condensation reaction was carried out at 130 to 140 ° C for 6 hours. On the way, generated methanol was removed from the system by passing nitrogen gas through. Crystals were precipitated in the course of the reaction, and at the end of the reaction, most of them were precipitated as crystals. After the reaction was completed, 50 ml of toluene was added,
After heating and adding 0.1 g of activated carbon, the mixture was filtered hot. When the filtrate was cooled, crystals precipitated. This was filtered to obtain crude crystals, which were further recrystallized with toluene to give 3-methyl-5-
17.9 g of white crystals of (4-methylbenzyl) salicylic acid were obtained (yield 70%). Mp 168 ℃ ~171 ℃ Elemental analysis (C ₁₆ H ₁₆ 0 _{3) ^{1 H-NMR (CDCl 3)}} 2.2 (s, 3H), 2.3 (s, 3H), 3.8 (s, 2H), 7.3 (m, 7H), 10.
5 (s, 1H)

[0016] Example 3 3-methyl salicylic acid 15.2 g (0.1 mol) were charged benzyl alcohol 11.9 g (0.11 mol) and aluminum chloride with crystal water _{(AlCl 3 · 6H 2 O)} 0.32g glass reactor, The condensation reaction was carried out at a reaction temperature of 110 to 135 ° C. for 6 hours.
On the way, generated water was removed from the system by passing a nitrogen gas through. After the completion of the reaction, the mixture was cooled, added with 70 ml of toluene, and heated.
After adding 0.1 g of activated carbon, the mixture was filtered hot. When this filtrate was cooled, crystals precipitated. This was filtered to obtain crude crystals, which were further recrystallized from toluene to obtain 16.4 g (yield: 68%) of white crystals of 3-methyl-5-benzylsalicylic acid.
Melting point 156 ℃ ～ 159 ℃

[0017]

According to the present invention, useful 3-alkyl-5-beta is obtained by reacting an inexpensive benzyl compound and a salicylic acid compound as raw materials using an aluminum chloride catalyst.
Ndyl salicylic acid can be easily produced and can be inexpensively supplied to the fields of pressure-sensitive paper and heat-sensitive paper, which have conventionally been expensive and their use has been limited. This greatly contributes to the development of industry.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) C07C 65/105-65/15 C07C 51/353 C07C 65/17 C07B 61/00 300 B01J 27/125 CA ( STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A salicylic acid compound represented by the general formula (I): ## STR1 ## (Wherein R ₁ represents an alkyl group or cycloalkyl group having 1 to 12 carbon atoms) A benzyl compound represented by the general formula (II) or (III) (Wherein, R ₂ and R ₃ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aralkyl group, an aryl group or a cycloalkyl group, and R ₄ represents a hydrogen atom or a C 1 to C ₄ A method for producing a salicylic acid derivative represented by the general formula (IV), wherein the reaction is carried out in the presence of an aluminum chloride catalyst (indicating a lower alkyl group). Embedded image (Wherein, R ₁ represents an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group, and R ₂ and R ₃ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aralkyl group,
Represents an aryl group or a cycloalkyl group)