JP3053447B2 - 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 useful as an intermediate for a color 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.

In addition, a method has been proposed in which salicylic acid is reacted with a styrene compound using an organic sulfonic acid or an inorganic acid in the presence of an aliphatic carboxylic acid to obtain di (α-methylbenzyl) salicylic acid (Japanese Patent Laid-Open Publication No. HEI 9 (1994)). 2-9104
3). In this case, since styrene is used, a styrene polymer is produced as a by-product, the production rate of the 3,5-substituted salicylic acid is poor, and acetic acid, an aliphatic carboxylic acid such as propionic acid and sulfuric acid, methanesulfonic acid and the like are used. 90 in combination with
Since the reaction is carried out at a temperature of up to 130 ° C. and the amount of acid used is 50% by weight or more based on salicylic acid, treatment of this waste acid is also a problem and is not an industrially advantageous method.

Further, when an attempt is made to produce 3-alkyl-5-α-methylbenzylsalicylic acid using 3-alkylsalicylic acid and styrene, a styrene polymer is also produced as a by-product, and purification is repeated to obtain the desired salicylic acid. There are manufacturing difficulties, such as the need to do this.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for producing a high-purity α-methylbenzylsalicylic acid derivative in a very easy reaction operation and in a high yield.

[0006]

Means for Solving the Problems The present inventors diligently studied to achieve the above object. As a result, they have found a method for obtaining a high-purity salicylic acid derivative in a high yield by reacting a salicylic acid compound with α-methylbenzyl halides in the presence of an acid catalyst, and have reached the present invention. That is, the present invention relates to a compound represented by the general formula [I]:

[0007]

Embedded image (Wherein R ₁ represents an alkyl group having 1 to 12 carbon atoms) and a salicylic acid compound represented by the general formula [II]:

[0008]

Embedded image (Wherein X represents a halogen atom, R ₂ and R ₃ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or an aralkyl group) , and the salicylic acid The α-me
Reaction ratio of 1.0 to 1.2 mol of tylbenzyl halides
In the presence of a Friedel-Crafts catalyst, the α-methyl
The reaction is carried out while dropping benzyl halides, and the compound represented by the general formula [III]

[0009]

Embedded image (Wherein, R ₁ represents an alkyl group having 1 to 12 carbon atoms;
₂ and R ₃ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or an aralkyl group).

The salicylic acid compound used in the present invention is represented by the general formula [I], wherein R ₁ is an alkyl group, that is, a linear alkyl group having 1 to 12 carbon atoms or a cyclic alkyl group having 5 to 7 carbon atoms. Represents Specific salicylic acid compounds include 3-methylsalicylic acid, 3-ethylsalicylic acid,
Examples include 3-isopropylsalicylic acid, 3-sec-butylsalicylic acid, 3-tert-butylsalicylic acid, 3-cyclohexylsalicylic acid, and 3-nonylsalicylic acid.

The α-methylbenzyl halides used in the present invention are represented by the general formula [II], wherein X represents a halogen atom. Examples of the type of the halogen atom include chlorine and bromine, and chlorine is preferable. R ₂ and R ₃ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or an aralkyl group. Specific examples of α-methylbenzyl halides include α-methylbenzyl chloride, o
-Methyl-α-methylbenzyl chloride, p-methyl-α-methylbenzyl chloride, m-methyl-α-methylbenzyl chloride, o-ethyl-α-methylbenzyl chloride, p-ethyl-α-methylbenzyl chloride, p -Isopropyl-α-methylbenzyl chloride, p-phenyl-α-methylbenzyl chloride,
p- (α, α-dimethylbenzyl) -α-methylbenzyl chloride, 2,3-dimethyl-α-methylbenzyl chloride, 2,4-dimethyl-α-methylbenzyl chloride, 2,5-dimethyl-α-methyl Benzyl chloride, 3,4-dimethyl-α-methylbenzyl chloride and the like. The amount of the α-methylbenzyl halide to be used is preferably 1.0 to 1.2 mol per 1 mol of the salicylic acid compound represented by the above general formula [I].

The Friedel-Crafts catalyst used in this reaction is, for example, a Lewis acid type catalyst such as ferric chloride, zinc chloride, aluminum chloride, stannic chloride, titanium tetrachloride, boron trifluoride, or a super strong acid. Known perfluoroalkanesulfonic acids, such as trifluoromethanesulfonic acid, Nafi which is a perfluoroalkanesulfonic acid resin
onH (trade name, manufactured by Dupont) or the like can be used. Among them, zinc chloride is particularly preferred. The amount of the catalyst used is in the range of 0.05 to 200 mol%, preferably 0.1 to 100 mol%, in consideration of economy, based on the salicylic acid compound represented by the general formula [I]. Reaction temperature is 2
It is in the range of 0 to 180 ° C, preferably in the range of 80 to 100 ° C. The reaction time is usually 1 to 20 hours.

In the reaction between the salicylic acid compound and α-methylbenzyl halides, a solvent may be used if necessary.
As the solvent, those inert to the reaction, for example, halogenated hydrocarbons such as 1,2-dichloroethane and 1,1,2-trichloroethane, and organic acids such as acetic acid and propionic acid can be used. When these solvents are used, the cost is preferably 30 times (volume / weight) or less in consideration of the economy of the raw material.

A general method for producing the salicylic acid derivative of the present invention is as follows: a salicylic acid compound represented by the general formula [I], α-methylbenzyl halides represented by the general formula [II] and a catalyst are charged in predetermined amounts, and The reaction may be performed at a predetermined temperature, or the reaction may be performed while charging a salicylic acid compound, a catalyst and a solvent in predetermined amounts, and then dropping α-methylbenzyl halides. The end point of this reaction can be determined while observing the reduction of the salicylic acid compound and α-methylbenzyl halide as raw materials by high performance liquid chromatography.

[0015]

The present invention will be described below in more detail with reference to examples. Example 1 In a 500 ml separable flask equipped with a thermometer, a reflux condenser and a stirrer, 38 g of 3-methylsalicylic acid (0.2 g) was added.
5 mol), 0.4 g of zinc chloride and 60 g of 1,2-dichloroethane. After the temperature was raised to 80 ° C., 42.2 g (0.3 mol) of 1-chloroethylbenzene was added dropwise at the same temperature over 4 hours. After the completion of dropping, the temperature is
Reacted for hours. Then, the mixture was cooled and treated with nitrogen gas for 1 hour to remove HCl gas. Then, the crystals were separated by filtration and dried. Further, recrystallization was performed with toluene to obtain the desired 5- (α-methylbenzyl) -3-methylsalicylic acid 5
5 g (86% yield) was obtained. The purity by high performance liquid chromatography was 99% or more. Melting point 129-1
31 ° C. Elemental analysis value C ₁₆ H ₁₆ O ₃ ¹ H-NMR (CDCl ₃ ) δ = 1.61 (d, 3H), 2.22 (s, 3
H), 4.1 (q, 1H), 7.08-7.37 (m, 6H), 7.64-7.67 (
m, 1H)

[0016]

According to the present invention, a high-purity α-methylbenzylsalicylic acid derivative useful as an intermediate of a developer for pressure-sensitive copying paper or as a developer for heat-sensitive paper can be obtained by a simple reaction operation. It provides an industrially advantageous process that can be produced in yield.

Continuation of front page (56) References JP-A-63-132857 (JP, A) JP-A-2-153779 (JP, A) JP-A-2-160815 (JP, A) JP-A-2-310086 (JP) , A) JP-B 51-25174 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 65/105 C07C 51/353

Claims (1)

(57) [Claims] 1. A compound of the general formula [I] (Wherein, R ₁ represents an alkyl group having 1 to 12 carbon atoms), and a salicylic acid compound represented by the following general formula [II]: (Wherein X represents a halogen atom, R ₂ and R ₃ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or an aralkyl group) , and the salicylic acid The α-me
Reaction ratio of 1.0 to 1.2 mol of tylbenzyl halides
In the presence of a Friedel-Crafts catalyst, the α-methyl
General formula [III] characterized in that the reaction is carried out while adding benzyl halides dropwise. (In the formula, R ₁ represents an alkyl group having 1 to 12 carbon atoms, R ₂
And R ₃ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or an aralkyl group).