CN107619379B - A kind of preparation method of 2- amidos azo aromatic compound - Google Patents

Abstract

A preparation method of a 2-amino azo aromatic compound. The 2-amino azo aromatic compound is prepared by reacting an azo aromatic compound with the structure of formula I with an amine. The reaction process is: the azo aromatic compound , amine, catalyzer and solvent are directly added in the reaction device, and described catalyzer is copper acetate; Described solvent is benzene or xylene or the mixture of the two, and the molar consumption of azobenzene is 1-3 times of amine molar number, Stir and heat to 100°C-130°C, react for 24 hours, and separate the product to obtain 2-aminoazoaromatic compound. The preparation method has simple synthesis route, low raw material price and high yield.

Description

A kind of preparation method of 2-amino azo aromatic compound

technical field

The invention relates to a chemical synthesis method, in particular to a preparation method of a 2-amino azo aromatic compound, belonging to the field of chemistry.

Background technique

Azoaromatic compounds are a class of important compounds with unique molecular skeletons, which are widely used in various functional materials such as pigments, dyes, photosensitive materials, food additives, and diagnostic reagents. Different types, quantities, and positions of substituents on the skeleton of azoaromatic compounds produce different physical and chemical properties. It has always been a research hotspot to develop and explore new methods for efficiently preparing azoaromatic compounds with various structures. So far, humans have developed many effective methods for synthesizing different azoaromatic compounds. The synthetic method of symmetrical azoaromatic compounds is simple and easy to synthesize. It can be obtained only by the reduction of nitroaromatic compounds or the oxidation of arylamines; The synthesis of asymmetric azoaromatic compounds requires the use of compounds such as nitroso compounds or aryl diazonium salts. Although such compounds are simple and easy to obtain and easy to synthesize, they are unstable at room temperature and easy to explode or decompose when exposed to light. There is a great safety risk in the synthesis and preparation, and its safety investment is also relatively large. In recent years, it has been reported that azobenzene and azide compounds are reacted to synthesize 2-amino azo derivatives under rhodium catalysis, but azide compounds Not only is it difficult to prepare, but it is also unstable and easy to explode. Therefore, no matter what method is used, it is difficult to prepare 2-amino azo aromatic compounds. The applicant discloses a dehydrogenation coupling to prepare aromatic compounds in Chinese Patent No. 2014106843824. In this patent, when DG is pyridine or pyrazole, the technical scheme in this patent realizes the preparation of arylamine by catalytic dehydrogenation coupling of cuprous bromide unstable in air, but After testing, in the case where DG is azo, the reaction of the scheme in this patent cannot be carried out at all, and the existence of 2-amino azoaromatic compound cannot be detected after a long time of reaction, so the technical scheme of this patent is in It cannot be realized when DG is azo, and a method for preparing 2-amino azoaromatic compounds through dehydrogenation coupling of amines is needed in chemical synthesis.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned problems existing in the synthesis of current 2-aminoazoaromatic compounds, and provide a preparation method of 2-aminoazoaromatic compounds.

In order to achieve the purpose of the present invention, the following technical scheme is adopted: a preparation method of a 2-amino azo aromatic compound, the described 2-amino azo aromatic compound has a structure of formula III, and the formula I The 2-amino azoaromatic compound of the structure of the formula III is prepared by reacting the azoaromatic compound with the amine of the formula (II) structure, and the reaction formula is as follows:

Among them: R is hydrogen or methyl or chlorine or fluorine, R ₁ , R ₂ , _R are alkyl or hydrogen or phenyl, the reaction process is: add azo aromatic compound, amine, catalyst and solvent directly into the reaction device , the catalyst is copper acetate; the solvent is benzene or xylene or a mixture of the two, the molar amount of azobenzene is 1-3 times the molar number of amine, stirring and heating the temperature to 100°C-130°C, the reaction After 24 hours, the product was isolated to give the 2-aminoazoaromatic compound.

The positive benefits of the present invention are the effects that the preparation method has simple synthesis route, easy-to-obtain raw materials, high safety of raw materials, high safety in the synthesis process, low cost of raw materials and high yield.

Detailed ways

In order to more fully explain the implementation of the present invention, the implementation examples of the present invention are provided, and these implementation examples are only illustrations of the present invention, and do not limit the scope of the present invention.

Example 1:

Add 72mg (0.4mmol) of azobenzene, 24mg (0.2mmol) of benzamide, 4mg (0.02mmol) of copper acetate, 0.1mL of benzene and 0.1mL of xylene into a 20mL reaction flask, ventilate with air, and heat to 120°C for reaction. After stirring for 24 hours, after the reaction, column chromatography separated to obtain 49 mg of the target product with a yield of 81%.

Example 2:

Add 84 mg (0.4 mmol) 4,4'-dimethylazobenzene, 24 mg (0.2 mmol) benzamide, 4 mg (0.02 mmol) copper acetate, 0.1 mL benzene and 0.1 mL xylene to a 20 mL reaction bottle, and pass air, heated to 120°C for reaction, and stirred for 24 hours. After the reaction, column chromatography separated to obtain 53 mg of the target product with a yield of 81%.

Example 3:

Add 100mg (0.4mmol) 4, 4'-dichloroazobenzene, 24mg (0.2mmol) benzamide, 4mg (0.02mmol) copper acetate, 0.1mL benzene and 0.1mL xylene to a 20mL reaction bottle, ventilate with air , heated to 120°C for reaction, and stirred for 24 hours. After the reaction, column chromatography separated to obtain 53 mg of the target product with a yield of 72%.

Example 4:

Add 87mg (0.4mmol) 4,4'-difluoroazobenzene, 24mg (0.2mmol) benzamide, 4mg (0.02mmol) copper acetate, 0.1mL benzene and 0.1mL xylene to a 20mL reaction bottle, ventilate with air , heated to 120°C for reaction, and stirred for 24 hours. After the reaction, column chromatography separated to obtain 46 mg of the target product with a yield of 68%.

Example 5:

Add 72mg (0.4mmol) of azobenzene, 12mg (0.2mmol) of acetamide, 4mg (0.02mmol) of copper acetate, 0.1mL of benzene and 0.1mL of xylene into a 20mL reaction flask, heat to 120°C for reaction, and stir After 24 hours of reaction, column chromatography separated to obtain 35 mg of the target product with a yield of 74%.

Embodiment 6:

Add 72mg (0.4mmol) of azobenzene, 27mg (0.2mmol) of N -phenylacetamide, 4mg (0.02mmol) of copper acetate, 0.1mL of benzene and 0.1mL of xylene into a 20mL reaction flask, ventilate with air, and heat to 120 ℃ for reaction and stirring for 24 hours. After the reaction, column chromatography separated to obtain 43 mg of the target product with a yield of 68%.

Following table one is the product and corresponding yield that adopt technical scheme synthesis of the present invention:

Table I

The mechanism of why this synthetic route can be realized is not clear. The discovery of this synthetic route is highly accidental. It was one of the experiments when the experimenters replaced the DG of the reactant in the patent 2014106843824 with azo to see if the reaction could still proceed. It was discovered by mistakenly adding copper acetate as cuprous bromide.

Claims (1)

1. a kind of preparation method of 2- amidos azo aromatic compound, the 2- amido azo aromatic compounds have formula III Structure, it is characterised in that：The formula of being prepared III is reacted with the amine of formula (II) structure using the structure azo aromatic compound of formula I The 2- amido azo aromatic compounds of structure, reaction equation are as follows：

Wherein：R is hydrogen or methyl or chlorine or fluorine, R₁、R₂It is for alkyl or hydrogen or phenyl, reaction process：By azo aromatics Object, amine, catalyst and solvent are directly added into reaction unit, and the catalyst is copper acetate；The solvent is benzene or two The mixture of toluene or the two, the mole dosage of azobenzene are 1-3 times of amine molal quantity, and agitating and heating temperature is to 100 DEG C -130 DEG C, it reacts 24 hours, separation product obtains 2- amido azo aromatic compounds.