CN-117402077-B - New synthetic method of aromatic azo compound

Abstract

The invention provides a novel synthesis method of aromatic azo compounds. The invention synthesizes the aromatic azo compound by one step by using aniline as the raw material, has high yield, strong substrate adaptability, lower cost, environmental protection, easy realization of industrialization and good application prospect.

Inventors

• HAN GUOZHI
• JIANG BO
• WANG JIANGUO

Assignees

• 徐州淮海生命科学产业研究院有限公司

Dates

Publication Date

20260505

Application Date

20231017

Claims (2)

1. 1. A method for preparing an aromatic azo compound, comprising the steps of: The method comprises the steps of dissolving a compound of a formula 1 and a compound of a formula 2 in an organic solvent, and reacting for 4-8 hours at 100-110 ℃ in the presence of oxygen under the catalysis of metal salt to generate a compound of a formula 3, wherein the metal salt is selected from the combination of Cu (OAc) 2 and NiCl 2 ; the organic solvent is selected from 1, 4-dioxane or toluene; The feeding mole number of Cu (OAc) 2 is 15% of the feeding mole number of the compound of formula 1, and the feeding mole number of NiCl 2 is 5% of the feeding mole number of the compound of formula 1; Wherein the compound of formula 1 is substituted with one or more R 1 , wherein the compound of formula 2 is substituted with one or more R 2 , R 1 and R 2 are independently selected from hydrogen, methyl, ethyl, methoxy, butyl, F, cl, and R 1 and R 2 are not substituted in the ortho position of the aniline when R 1 and R 2 are selected from different substituents.
2. 2. The process according to claim 1, wherein the compound of formula 1 and the compound of formula 2 are selected from the group consisting of,

Description

New synthetic method of aromatic azo compound Technical Field The invention belongs to the field of organic synthesis, and particularly relates to a novel method for synthesizing an aromatic azo compound. Background Aromatic azo compounds are a class of aromatic compounds having an n=n double bond. Has a larger electron conjugation effect. Furthermore, the structure of the double bond results in azo compounds having cis and trans isomerism. In general, trans vs cis are stable. Azo compounds have unique photochromic phenomena, and cis and trans isomers can be mutually converted under the condition of illumination or heating. The unique properties of azo compounds make them widely applicable in the fields of bioactive ligands, cosmetics, organic dyes, food additives, free radical initiators, etc. In particular, organic azo dyes account for 1/3 of the industrial dyes worldwide. Therefore, how to synthesize azo compounds rapidly, simply and environmentally friendly is an extremely attractive field, and two methods for synthesizing aromatic azo compounds are conventionally used, namely, coupling reaction of diazonium salts with aromatic amines or phenols under acidic conditions. Secondly, the Mills reaction of nitrosobenzene and aromatic amine. As shown in fig. 1. When diazonium salts are used as starting materials, the other substrate needs to have a high reactivity to allow the reaction to proceed. It is generally desirable to have the hydroxyl (OH) or amino (NH 2) groups directly attached to the benzene ring. This results in limitations in the reaction. In order to overcome the defects of the traditional reaction, follow the sustainable development, and seek a more environment-friendly and simple-to-operate synthetic method to draw attention of more scientific researchers. In recent years, it has been reported that n=n coupling reactions of aromatic amines or reduction of n=n coupling of aromatic nitro compounds are catalyzed by using complex compounds of transition metal compounds such as copper, nickel, palladium, rhodium, iron, manganese, etc., or MOF materials. The transition metal compound is used as a catalyst, so that the reaction yield can be improved, and the reaction has good selectivity. As shown in fig. 2. However, there are still great challenges in the existing methods of synthesizing azo compounds, in which there are often disadvantages of using different stoichiometries of toxic metal salts, strong oxidants, strong bases and high boiling solvents (DMSO, DMF, toluene). In particular, some organic solvents and organic bases can cause certain damage to the environment. Disclosure of Invention Aiming at the problems of complexity in the synthesis of the traditional azo compound and high cost in the traditional azo compound synthesis, the invention provides a novel method for synthesizing the aromatic azo compound. The preparation method of the aromatic azo compound comprises the following steps: The compound of formula 1 and the compound of formula 2 are dissolved in an organic solvent and react under the catalysis of metal salt at a certain temperature to generate the compound of formula 3, wherein the metal salt is selected from the combination of CuNO 3 or Cu (OAc) 2 and FeCl 3、FeCl2、ZnCl2、CoCl2、NiCl2、NiCO3 or NiSO 4; Wherein the compound of formula 1 is substituted with one or more R 1, wherein the compound of formula 2 is substituted with one or more R 2, R 1 and R 2 are independently selected from hydrogen, C1-C4 alkyl, C1-C3 alkoxy, halogen, dimethylamino or anilino, and R 1 and R 2 are not substituted in the ortho position to the aniline when R 1 and R 2 are selected from different substituents. Preferably, the metal salt is selected from the group consisting of Cu (OAc) 2 in combination with NiCl 2. Preferably, the molar amount of Cu (OAc) 2 is 15% of the molar amount of the compound of formula 1, and the molar amount of NiCl 2 is 5% of the molar amount of the compound of formula 1. Preferably, the organic solvent is selected from one or more of THF, DMSO, DMF, 1, 4-dioxane or toluene. Preferably, the organic solvent is selected from toluene. Preferably, the reaction temperature is 60 ℃ to 110 ℃, preferably 100 ℃. Preferably, the reaction time is 4-8 hours. Preferably, the reaction also requires the presence of oxygen. The invention also provides a preparation method of the aromatic azo compound, which comprises the following steps: The compound of formula 4 and the compound of formula 5 are dissolved in an organic solvent and react under the catalysis of metal salt at a certain temperature to generate the compound of formula 6; Wherein the compound of formula 4 is substituted with one or more R 4 wherein the compound of formula 5 is substituted with one or more R 5, R 4 and R 5 are independently selected from hydrogen, C1-C4 alkyl, C1-C3 alkoxy, halogen, dimethylamino or anilino, and R 4 and R 5 are not substituted in the ortho position to the aniline when R 4 and R 5 are selected from d