JPH08143523A - Production of 3-(n-alkylamino)-acylanilide - Google Patents

Abstract

PURPOSE: To provide a method of producing a 3-(N-alkylamino)acylanilide, an important intermediate for dyes, which can solves the environmental problems on the production through the conventional process, the corrosion problems in the production facilities and the quality problems of the product. CONSTITUTION: A 3-amino-acylanilide is dissolved in a solvent, an alkyl-aldehyde is added to the solution to effect the addition reaction of the aldehyde to the anilide. This reaction mixture is catalytically hydrogenated in the presence of a catalyst. Or 3-amino-acylanilide is dissolved in a solvent and an alkylaldehyde is dripped to the solution, as the solution is pressurized with hydrogen in the presence of a hydrogenation catalyst, to effect the reductive alkylation reaction. Then, the catalyst is filtered off, the filtrate is distilled under reduced pressure at a temperature lower than 50 deg.C to recover the solvent and the unreacted substances. Thus, the objective 3-(N-alkylamino)-acylanilide of high purity is produced with increased commodity value.

Description

Detailed Description of the Invention

[0001]

Industrial field: 3- (N-alkylamino) -acylanilides are industrially very important compounds as intermediates for dyes.

[0002]

BACKGROUND OF THE INVENTION Conventional 3- (N-alkylamino) -acylanilides are prepared by alkylating 3-amino-acylanilides by the addition of alkyl chloride or alkyl sulfuric acid in the presence of alkali carbonate to give 3- (N-alkylamino) Methods for obtaining -alkylamino) -acylanilides are known.

[0003]

In the conventional method, it is necessary to neutralize unreacted alkyl chloride or alkyl sulfuric acid after the reaction, but since the compound has an acylamino group, it varies depending on the pH condition. The neutralization process is very difficult because of the possibility.

Further, a large amount of waste water is generated for separating and purifying salts obtained by neutralization and alkali salts used as a deoxidizing agent, which causes environmental problems.

In addition, there arises a problem of corrosion of manufacturing equipment due to floating sulfate ions generated during the reaction.

Further, the 3- (N-alkylamino) -acylanilides obtained by the conventional method have a problem in purity and shape because they contain a small amount of impurities, and the commercial value is impaired.

The present invention eliminates the need for neutralization treatment, solves the problem of drainage, eliminates the corrosion of manufacturing equipment, and raises the quality of 3- (N-alkylamino) -acylanilides of high quality never seen before. It is a production method that can be obtained in a yield.

[0008]

[Means for Solving the Problems] 3- (N
As a new method for producing -alkylamino) -acylanilides, the inventors have made intensive studies and invented the synthesis by a reductive alkylation method.

Furthermore, the solvent and unreacted materials are recovered by distilling the reaction solution under reduced pressure at 50 ° C. or lower,
We have invented a method for purifying (N-alkylamino) -acylanilides.

According to the present invention, industrially high yield,
A method for producing high quality 3- (N-alkylamino) -acylanilides has been completed.

That is, according to the present invention, 3-amino-acylanilides and alkyl aldehydes are dissolved in a solvent and subjected to reductive alkylation reaction in the presence of a catalyst and hydrogen to give 3- (N-alkylamino) -acylanilides. After the synthesis, the catalyst was separated from the reaction solution, the solvent and unreacted alkyl aldehyde were distilled and recovered under reduced pressure at 50 ° C. or lower, and further cooled to give 3- (N-alkylamino)-
A method for producing 3- (N-alkylamino) -acylanilides, which comprises obtaining the acylanilides as highly pure crystals.

The 3- (N-alkylamino) -acylanilides produced by the present invention are represented by the general formula of [Chemical Formula 1].

[0013]

Embedded image

In the formula, R and R'represent an alkyl group having 1 to 3 carbon atoms.

In the formula, X is H, methoxy or ethoxy group.

Alkyl aldehyde is formaldehyde, acetaldehyde or propionaldehyde.

The solvent is methanol, ethanol or propanol.

As the catalyst, a catalyst having a reductive alkylation ability such as platinum, palladium or nickel is used.

In the reductive alkylation reaction of the present invention, 3-amino-acylanilides are dissolved in a solvent, an alkylaldehyde is added thereto, and the alkylaldehyde is added to the 3-amino-acylanilides, and then a catalyst is added. Then, the reduction reaction is performed under hydrogen pressure, or the 3-amino-acylanilides are dissolved in a solvent, a catalyst is added thereto, and the alkyl aldehyde is gradually added dropwise under hydrogen pressure. .

The alkyl aldehyde is used in a 1- to 1.1-fold molar amount with respect to 1 mol of 3-amino-acylanilides.

The solvent is 3-amino-acylanilide 1
1 to 20 parts by weight is used with respect to parts by weight.

The catalyst is a 3-amino-acylanilide 1
0.005 to 0.1 part by weight is used with respect to parts by weight.

The reaction temperature is in the range of 15 to 150 ° C,
The reaction is preferably carried out at 40 ° C or lower.

The pressure of hydrogen is 20 kg / cm ² G or less.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

[0026]

【Example】

<Example 1> 222 g (1.5 mol) of 3-amino-acetanilide, 2,000 g of ethanol, and 66 g of acetaldehyde were placed in a 5 L autoclave made of SUS equipped with a stirrer.
(1.5 mol) was charged and the temperature was raised to 60 ° C with stirring.
After 1 hour, the temperature was cooled to 30 ° C, 5.5g of carbon-palladium catalyst was added, and the hydrogen pressure was 10kg.
Hydrogen was supplied at / cm ² G.

The time when the absorption of hydrogen disappeared was taken as the end point of the reaction, and it took 5 hours to complete the reaction.

After cooling to room temperature, the catalyst was separated by filtration to obtain a reaction liquid.

This reaction solution was placed in an eggplant-shaped flask and kept at 50 ° C. in a water bath to recover ethanol as a solvent and a small amount of unreacted acetaldehyde under reduced pressure of 40 mmHg.

The crystals remaining in the eggplant-shaped flask were scraped with a spatula and naturally dried.

As a result of analysis, this product was 3- (N-ethylamino) -acetanilide, and the yield was 99.1%.
Met.

<Example 2> 270 g (1.5 mol) of 3-amino-4-methoxy-acetanilide and 2,000 g of methanol were placed in a 5 L autoclave made of SUS equipped with a stirrer.
g, carbon palladium catalyst 6.5 g, and reaction temperature 3
While maintaining at 5 ° C and hydrogen pressure of 10 kg / cm ² G, 66 g (1.5 mol) of acetaldehyde was gradually added dropwise.

The time point at which the absorption of hydrogen disappeared was taken as the end point of the reaction, and it took 5 hours to complete the reaction.

After cooling to room temperature, the catalyst was separated by filtration to obtain a reaction solution.

The solvent and unreacted acetaldehyde were recovered from the reaction solution in a reactor at 50 ° C. under a reduced pressure of 40 mmHg.

The product remaining in the reactor was taken out and dried at a low temperature in a dryer.

As a result of analysis of this product, the yield of 3- (N-ethylamino) -4-methoxy-acetanilide was 9
It was 8.6%.

[0038]

INDUSTRIAL APPLICABILITY 3-Amino-acylanilides are treated with 3- (N-alkylamino)-by a reductive alkylation reaction.
Acylanilide was prepared, and from this reaction solution, a pressure of 50 ° C was applied.
The method for producing 3- (N-alkylamino) -acylanilide, which recovers the solvent and unreacted alkylaldehyde below, is a new industrial method of 3- (N-alkylamino) -acylanilide which is not available in conventional methods. It is a manufacturing method.

When 3- (N-alkylamino) -acylanilides are produced by utilizing the present invention, in the environmental problems due to a large amount of waste water, equipment corrosion problems, and product quality problems, they are better than conventional methods. It is a method for producing 3- (N-alkylamino) -acylanilides, which shows remarkable progress and is industrially extremely advantageous.

Claims (3)

[Claims] 1. A 3- (N-alkylamino) -acylanilide is synthesized by a reductive alkylation reaction of a 3-amino-acylanilide and an alkylaldehyde in the presence of a solvent, a catalyst and hydrogen. A method for producing 3- (N-alkylamino) -acylanilides by separating the catalyst from the liquid and distilling and recovering the solvent and a small amount of alkyl aldehyde from the furnace liquid under reduced pressure at 50 ° C or lower. 2. The reductive alkalization reaction according to claim 1, wherein 3-amino-acylanilides are dissolved in a solvent,
A method for performing a reaction characterized by adding alkyl aldehyde to this, adding the alkyl aldehyde to 3-amino-acylanilides, adding a catalyst to this reaction solution, and supplying reductive alkylation by supplying hydrogen. . 3. The reductive alkylation reaction according to claim 1, wherein 3-amino-acylanilides are dissolved in a solvent,
A catalyst is added to this, and it is placed under hydrogen pressure. A method for carrying out a reaction characterized in that an alkyl aldehyde is added dropwise to this for reductive alkylation.