CN110818620A

CN110818620A - Preparation method of meta-aromatic aldehyde

Info

Publication number: CN110818620A
Application number: CN201911123542.7A
Authority: CN
Inventors: 李刚; 贾春起; 吴妮妮; 仲磊; 蔡晓凤
Original assignee: Anyang Normal University
Current assignee: Anyang Normal University
Priority date: 2019-11-17
Filing date: 2019-11-17
Publication date: 2020-02-21

Abstract

A preparation method of meta-aromatic aldehyde adopts aromatic compound as raw material, carbon tribromide as formylation reagent, and the meta-aromatic aldehyde is prepared in the presence of alkali, additive, solvent and catalyst, wherein the alkali is potassium carbonate or sodium carbonate; the additive is acetyl leucine; the solvent is acetonitrile or 1, 4-dioxane; adding the aromatic compound, carbon tribromide, ruthenium catalyst, alkali and solvent directly into a reaction device, stirring and heating to 110-130 ℃, reacting for 20-25 hours, and separating the product to obtain the meta-substituted aromatic aldehyde. The method utilizes cheap and easily-obtained carbon tribromide as an acylation reagent to directly react with the meta-position aryl C-H bond C-H under the catalysis of ruthenium, and is convenient and low in cost.

Description

Preparation method of meta-aromatic aldehyde

Technical Field

The invention relates to a preparation process of meta-aromatic aldehyde, in particular to a process for synthesizing meta-aromatic aldehyde by reacting an aromatic compound with carbon tribromide, and belongs to the field of chemistry.

Background

Because of the rich reactivity of aldehyde group, aromatic aldehyde is an important chemical raw material, and can be conveniently further reacted to prepare various common compounds such as alcohol, amine, carboxylic acid and derivatives thereof, alkene, benzyl halide and the like. There are also many methods for the synthesis of aromatic aldehydes, the most efficient of which is the direct formylation of aryl C-H bonds, such as the Gattermann-Koch reaction, Reimer-Tiemann reaction, Duff reaction, Rieche formylation and Vilsmeier-Haag reaction, which are well known reactions for the synthesis of aryl aldehydes by direct reaction of aryl C-H bonds with formylating reagents and are commonly used in chemical manufacturing and laboratory synthesis, but these formylation reactions are mainly at the ortho-or para-position of the substituents, resulting in the formation of ortho-or para-substituted aromatic aldehydes, while meta-aromatic aldehydes cannot be directly converted from aryl C-H bonds.

Disclosure of Invention

The invention aims to overcome the problem that only ortho-or para-substituted aromatic aldehyde can be synthesized in the traditional method for synthesizing aromatic aldehyde by directly formylating aryl C-H bond, thereby providing a process for synthesizing meta-substituted aromatic aldehyde by directly formylating meta-aryl C-H bond under the catalysis of ruthenium.

In order to realize the purpose of the invention, the following technical scheme is adopted: a preparation method of meta-aromatic aldehyde is disclosed, wherein the meta-aromatic aldehyde is of a structure shown in a formula III, an aromatic compound of a structure shown in a formula I is used as a raw material, and carbon tribromide shown in a formula II is used as a formylation reagent, and the reaction formula is as follows:

wherein: r is hydrogen or methoxy or methyl or phenyl; DG is 2-pyridyl or 2-pyrimidinyl, and the ruthenium catalyst is bis (4-methylisopropylphenyl) ruthenium diacetate; the alkali is potassium carbonate or sodium carbonate; the additive is acetyl leucine; the solvent is acetonitrile or 1, 4-dioxane; adding the aromatic compound, carbon tribromide, ruthenium catalyst, alkali and solvent directly into a reaction device, stirring and heating to 110-130 ℃, reacting for 20-25 hours, and separating the product to obtain the meta-substituted aromatic aldehyde.

Further, the method comprises the following steps of; the molar amount of carbon tribromide is 2-4 times of the molar amount of the aromatic compound.

The invention has the positive and beneficial technical effects that: the method utilizes cheap and easily-obtained carbon tribromide as an acylation reagent to directly react with the meta-position aryl C-H bond C-H under the catalysis of ruthenium, and is convenient and low in cost.

Detailed Description

In order to more fully explain the implementation of the present invention, the implementation examples of the present invention are provided, which are merely illustrative of the present invention and do not limit the scope of the present invention.

Example 1:

31mg (0.2mmol) of 2-phenylpyridine, 151mg (0.6 mmol) of carbon tribromide, 6mg (0.01mmol) of bis (4-methylisopropylphenyl) ruthenium diacetate, 11mg (0.06 mmol) of acetylleucine, 82mg (0.6 mmol) of potassium carbonate and 1mL of acetonitrile were charged in a 20mL pressure-resistant reaction tube, the mixture was sealed under nitrogen, heated to 120 ℃ for reaction, stirred for 24 hours, and after the reaction, column chromatography was performed to obtain 19mg of the objective product, namely, 3- (2-pyridyl) benzaldehyde, with a yield of 53%.

Example 2:

31mg (0.2mmol) of 2-p-tolylpyridine, 151mg (0.6 mmol) of carbon tribromide, 6mg (0.01mmol) of bis (4-methylisopropylphenyl) ruthenium diacetate, 11mg (0.06 mmol) of acetylleucine, 82mg (0.6 mmol) of potassium carbonate, 1mL of acetonitrile, sealing under nitrogen, heating to 120 ℃ for reaction, stirring for 24 hours, and after the reaction, separating by column chromatography to obtain 20.5mg of the target product, namely, 2-methyl-5- (2-pyridyl) benzaldehyde, with the yield of 52%.

Example 3:

31mg (0.2mmol) of 2-p-methoxyphenylpyridine, 151mg (0.6 mmol) of carbon tribromide, 6mg (0.01mmol) of bis (4-methylisopropylphenyl) ruthenium diacetate, 11mg (0.06 mmol) of acetylleucine, 82mg (0.6 mmol) of potassium carbonate, 1mL of acetonitrile, which are sealed under nitrogen, are charged into a 20mL pressure-resistant reaction tube, the reaction mixture is heated to 120 ℃ for reaction, and after the reaction, column chromatography is performed to obtain 22.6mg of the objective product, namely 3- (2-pyridyl) -6-methoxybenzaldehyde, with a yield of 53%.

Example 4:

31mg (0.2mmol) of 2-phenylpyrimidine, 151mg (0.6 mmol) of carbon tribromide, 6mg (0.01mmol) of bis (4-methylisopropylphenyl) ruthenium diacetate, 11mg (0.06 mmol) of acetylleucine, 82mg (0.6 mmol) of potassium carbonate, 1mL of acetonitrile, and sealing under nitrogen were added to a 20mL pressure-resistant reaction tube, and the mixture was heated to 120 ℃ for reaction, stirred for 24 hours, and after the reaction, column chromatography was performed to obtain 24.6mg of the objective 3- (2-pyrimidinyl) benzaldehyde in 67% yield.

Example 5:

31mg (0.2mmol) of 2-p-tolylpyrimidine, 151mg (0.6 mmol) of carbon tribromide, 6mg (0.01mmol) of bis (4-methylisopropylphenyl) ruthenium diacetate, 11mg (0.06 mmol) of acetylleucine, 82mg (0.6 mmol) of potassium carbonate, 1mL of acetonitrile, sealing under nitrogen, heating to 120 ℃ for reaction, stirring for 24 hours, and after the reaction, separating by column chromatography to obtain 22.6mg of the target product, namely, 2-methyl-5- (2-pyrimidinyl) benzaldehyde, with the yield of 57%.

The following table one is a product synthesized by the technical scheme of the invention and the corresponding yield:

watch 1

Claims

1. A preparation method of meta-aromatic aldehyde is disclosed, wherein the meta-aromatic aldehyde has a structure shown in a formula III, and is characterized in that: the aromatic compound with the structure of formula I is used as a raw material, and carbon tribromide shown in formula II is used as a formylation reagent to prepare the compound, and the reaction formula is as follows:

2. The process for producing a meta aromatic aldehyde according to claim 1, wherein: the molar amount of carbon tribromide is 2-4 times of the molar amount of the aromatic compound.