JPS58128339A - Preparation of beta-aroylacrylic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a medicine, agricultural chemical or intermediate therefor selectively in high yield, by reacting an aromatic compound with maleic anhydride in the presence of anhydrous aluminum chloride while removing hydrogen chloride to the outside of the system. CONSTITUTION:An aromatic compound consisting of an aromatic hydrocarbon or aromatic halogenated hydrocarbon, particularly a compound expressed by the formula (R1 is secondary alkyl; R2 and R3 are H, lower alkyl or halogen) is reacted with maleic anhydride in the presence of anhydrous aluminum chloride in a solvent, preferably dichloromethane or 1,2-dichloroethane, under reduced pressure or an inert gas, particularly nitrogen or air, is introduced into the reaction mixture to carry out the reaction while removing 80% or more formed hydrogen chloride to the outside of the system. Thus, the aimed beta-aroylacrylic acid is obtained advantageously by suppressing side reactions, e.g. dealkylation or intramolecular alkylation.

Description

Detailed Description of the Invention The present invention provides a method for producing β-aroyl acrylic acid by reacting an aromatic compound and maleic anhydride in the presence of aluminum chloride, in which the reaction is performed while removing hydrogen chloride from the system. In particular, the present invention relates to a method for selectively producing β-aroyl acrylic acid in high yield.

β-Aroyl acrylic acid is used as a medicine, agrochemical, or an intermediate for their production.

It is known that β-aroyl acrylic acid is produced by a 7-Riedel-Krach reaction between an aromatic compound and maleic anhydride. and R6 represents hydrogen, a lower alkyl group, or a halogen group), side reactions such as dealkylation and intramolecular alkylation occur, and the yield of β-aroyl acrylic acid decreases. It is difficult to say that I am necessarily satisfied.

The present inventors have conducted intensive studies to suppress the side reactions mentioned above and improve the selectivity and yield of β-aroyl acrylic acid, and as a result, the hydrogen chloride produced in the reaction was transported outside the prefecture It was discovered that β-aroyl acrylic acid can be obtained selectively and in high yield by carrying out the reaction while removing it, and the present invention was achieved based on this discovery.

That is, in the present invention, β-
In the method for producing aroyl acrylic acid, by performing the reaction under reduced pressure or introducing a gas inert to the reaction into the reaction mixture, while removing 80% or more of the generated hydrogen chloride from the system, β characterized by reacting
- A method for producing aroyl acrylic acid.

The aromatic compound used in the method of the present invention is an aromatic compound consisting of an aromatic hydrocarbon or an aromatic halogenated hydrocarbon, and is preferably of the general formula (wherein R is a secondary alkyl group, R2 and R3 represents a hydrogen atom, a lower alkyl group or a halogen atom. Specifically, these aromatic compounds include, for example, cumene, 3-metadiisopropylbenzene, L3y5 1J isopropylbenzene, 5-fluoro-1,3-diisopropylbenzene, 5-chloro-1,3-diisopropylbenzene, and 5-chloro-1,3-diisopropylbenzene. Bromo-1,3-diisopropylbenzene, 3.
5-dichlorocumene, metadi5ea-butylbenzene, 1,3.5-)so5ee-butylbenzene, 5-
Examples include chloro-1,3-di-BeQ-butylbenzene and 5-chloro-1,3-di-5ec-butylbenzene. Among these, 1-5,5-)
Diisopropylbenzene, 1,3.5-tIJ-sec
- Particular preference is given to applying the method of the invention to butylbenzene.

In the method of the invention, the reaction between the aromatic compound and maleic anhydride is carried out in the presence of anhydrous aluminum chloride.

The amounts of maleic anhydride and anhydrous aluminum chloride to be used are usually about 0.8 to 1.5 mol, respectively, and about 1.9 to 2.5 mol, respectively, per 1 mol of the aromatic compound, preferably about 0.8 to 1.5 mol, respectively. 95 to 1.1 mol, about 2.0 to 2.1 mol may be used.

Although the reaction proceeds without a solvent, it is preferable to use an inert solvent for the reaction in order to control the progress of the reaction and suppress the production of by-products. Examples of solvents used for this purpose include halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, and chlorobenzene, and nitro compounds such as nitromethane and nitrobenzene.
, 2-dichloroethane is preferably used.

In the method of the present invention: 1. 8 of hydrogen chloride produced in the reaction
It is necessary to remove 0% or more from the reaction system, and more preferably 95% or more. If the hydrogen chloride removal rate is less than 80%, the selectivity to β-aroyl acrylic acid and its yield will decrease. Methods for removing hydrogen chloride produced in the reaction from the reaction system include conducting the reaction while introducing an inert gas such as nitrogen, air, helium, or argon into the reaction mixture in the reaction system; There is a method in which the reaction is carried out while reducing the pressure of the reaction system to promote the removal of hydrogen chloride.

When the reaction is carried out under reduced pressure, the pressure is usually 10 to 500
mmHg5 preferably 50 to 2D OmmHB
is within the range of Among these methods, the method of introducing nitrogen is particularly preferred.

In the method of the present invention, the aromatic compound is added dropwise to a mixture consisting of maleic anhydride, anhydrous aluminum chloride, and optionally a solvent. A method of adding anhydrous aluminum chloride to a solution to cause a reaction,
The reaction can be carried out by any method, such as by dropping a mixture of maleic anhydride and anhydrous aluminum chloride into an aromatic compound and a solvent; Particularly preferred is a method in which the aromatic compound is added dropwise for reaction.

The reaction temperature is usually in the range of 0 to 80°C, preferably 10 to 30°C.

In the method of the present invention, the target β-aroyl acrylic acid can be obtained by hydrolyzing the mixture after the completion of the reaction, extracting it, concentrating it, and treating it according to conventional methods such as sublimation, crystallization, and distillation. . EXAMPLES Next, the method of the present invention will be specifically explained using Examples, but the present invention is not limited thereto.

Example 1 3 equipped with stirrer, dropping device, cooler and thermometer
9-81 g of maleic anhydride in a 00 mg four-loaf flask
(0.1 mol) and 1,2-dichloroethane 100 m5
and anhydrous aluminum chloride 2 while keeping it at 15℃.
8.0 g (0.21 mol) were added. After stirring the mixture for 20ml at 15°C, 1.3.5-
) 20.43 g (0.1 mol) of diisopropylbenzene was added dropwise over 1.5 hours. Simultaneously with the start of dropping triisopropylbenzene, nitrogen was supplied at a flow rate of 450 mβ/m 1
After the dropwise addition was completed, the reaction was further carried out at 15° C. for 1 hour while continuing to blow nitrogen into the reaction mixture.

During this time, 98% of the generated hydrogen chloride was removed from the reaction system. The reaction mixture was poured into water containing 20 m4 of concentrated hydrochloric acid for hydrolysis, ether was added to separate the mixture, and after washing with water and drying, the solvent was distilled off. The generated β-(2,
As a result of quantifying 4,6-)diisopropylbenzoyl)acrylic acid by gas chromatography, the yield was 95%.

Example 2 1.3.5-tri-5ec-butylbenzene 2 instead of 1.3.5-)diisopropylbenzene in Example 1
Example 1 except that 4.63 g (o, 1 mol) was used.
When the reaction was carried out in the same manner as above, β-(2,4,6-tri-5eC-butylbenzoyl)acrylic acid was obtained in a yield of 93%.
Obtained with. The removal rate of hydrogen chloride gas generated during this reaction was 96%.

Example 3 Di-5-chloro-1,3-diisopropylbenzene 19 instead of 1.3.5-)liisopropylbenzene in Example 1
-Producted in the same manner as in Example 1 except that 67 g (osmol) was used, and β-(2-chloro-4,6-diisopropylbenzoyl)acrylic acid and β-(4-chloro-2,6-
8-diisopropylbenzoyl)acrylic acid was produced in yields of 72% and 13%, respectively. The removal rate of hydrogen chloride in this case was 95%.

Example 4 A reaction was carried out in the same manner as in Example 1 except that 100 J of methylene chloride was used instead of 1,2-dichloroethane in Example 1, and β-(2,4,6-triimbrobylbenzoyl) was obtained. The yield of acrylic acid was 96%. The hydrogen chloride removal rate in this case was 98%.

Example 5 Nitrogen flow ffi450mj7/mj of Example 1, n 15
The reaction was carried out in the same manner as in Example 1 except that the reaction rate was changed to 0 m6/min, and the yield of β-(2,4,6-)diisopropylbenzoyl)acrylic acid was 93%.

The removal rate of hydrogen chloride in the reaction mixture was 94%.

Example 6 The reaction was carried out in the same manner as in Example 1 except that air was blown in instead of nitrogen in Example 1, and β-(2,4,6-1
-Yield of lyisopropylbenzoyl)acrylic acid is 95
%Met. Removal rate of hydrogen chloride in reaction mixture is 98%
Met.

Example 7 The same procedure as in Example 1 was carried out except that instead of blowing in nitrogen as in Example 1, a water pump was used to maintain the pressure in the reaction system at 1.00 mmHg. 6-)
The yield of IJ isopropyl benzoyl) acrylic acid is 93
%Met. Removal rate of hydrogen chloride in reaction mixture is 95%
Met.

Example 8 The same procedure as in Example 1 was carried out except that the reaction temperature in Example 1 was changed from 15°C to 25°C. The yield of β-(2,416-triisopropylbenzoyl)acrylic acid was 91%. there were. The removal rate of hydrogen chloride in the reaction mixture was 98%.

Comparative Example 1 When the same operation as in Example 1 was performed without blowing nitrogen, the yield of β-(2,4,6-lyisopropylbenzoyl)acrylic acid was 90%.

The removal rate of hydrogen chloride in the reaction mixture was 14%.

Claims (1)

[Claims] (1) β-aroyl acrylic acid is produced by reacting an aromatic compound consisting of an aromatic hydrocarbon or an aromatic non-logogenated hydrocarbon with maleic anhydride in the presence of anhydrous aluminum chloride. In the production method, the reaction is performed while removing 80% or more of the generated hydrogen chloride from the reaction system by conducting the reaction under reduced pressure or introducing a gas inert to the reaction into the reaction mixture. Characteristic method for producing β-aroyl acrylic acid. Q) The aromatic compound has the general formula (wherein R1 is a secondary alkyl group, R2 and R3 are a hydrogen atom, a lower alkyl group, or a halogen atom).
The method according to claim (1), which is a compound represented by: (3) The method according to claim (1), wherein the reaction is carried out in the presence of a solvent of dichloromethane or 1,2-dichloroethane. (4) The method according to claim (1), wherein the gas inert to the reaction introduced into the reaction mixture is nitrogen or air. (5) According to claim 1, in which aluminum chloride is added to a mixture of maleic anhydride and a solvent to form a complex, and an aromatic compound is added dropwise to the mixture to react. Method.