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CN-121974783-A - Method for dehalogenation reduction of electron-rich aryl halide

CN121974783ACN 121974783 ACN121974783 ACN 121974783ACN-121974783-A

Abstract

The invention discloses a dehalogenation and reduction method of an electron-rich aryl halide, which takes the aryl halide as a raw material, and prepares corresponding aromatic compounds through heating reaction in the presence of phosphorous acid, iodine simple substance and solvent. The method directly avoids the defect that the prior mainstream method needs to use an expensive transition metal catalyst and an equivalent metal reagent, takes low-cost low-toxicity and stable phosphorous acid as a reducing agent, takes iodine simple substance as a catalyst, and reduces the electronic-rich aryl halide into corresponding aromatic hydrocarbon through one-step dehalogenation, has the advantages of no metal participation, simplicity in operation, low cost, environment friendliness and the like, avoids the limitations of using the metal reagent and difficult mass production of special equipment, and the byproduct generally comprises phosphoric acid and corresponding phosphorus salt thereof after the phosphorous acid is reacted, can be quickly removed through washing, is simple in post-treatment, and is beneficial to industrial production.

Inventors

  • XIAO JING
  • GE XIUMIN
  • XIE YUXIANG
  • WANG MENGFAN
  • YIN SHUANGFENG

Assignees

  • 湖南科技大学

Dates

Publication Date
20260505
Application Date
20260403

Claims (9)

  1. 1. The method is characterized in that aryl halide is taken as a raw material, and is heated to react in the presence of phosphorous acid, iodine simple substance and solvent to prepare corresponding aromatic hydrocarbon compounds, wherein the reaction equation is shown in a formula I: A formula I; Wherein the aromatic ring in the aryl halide is an aromatic ring containing electron-rich substituent, the electron-rich substituent is one or more of hydrocarbon group, methoxy group, amino group, imino group and amino group, the aromatic ring is benzene ring or naphthalene ring or benzene ring or naphthalene ring containing alkyl substituent, and X is Cl, br or I.
  2. 2. The method of claim 1, wherein the aryl halide is selected from one of the following structural formulas: 、 、 、 、 、 、 、 、 、 、 、 、 。
  3. 3. the method according to claim 1 or 2, wherein the molar ratio of the aryl halide to the phosphorous acid is 1:1-8, the molar ratio of the aryl halide to the iodine simple substance is 1:0.01-1, and the concentration of the aryl halide in the solvent is 0.2-1.0 mol/L.
  4. 4. The method of claim 3, wherein the molar ratio of the aryl halide to the phosphorous acid is 1:2-5, and the molar ratio of the aryl halide to the elemental iodine is 1:0.05-0.5.
  5. 5. The process according to claim 1 or 2, characterized in that the solvent is 1, 2-dichloroethane, chlorobenzene, chloroform, dichloromethane, benzene, or toluene.
  6. 6. The method according to claim 1 or 2, wherein the atmosphere of the heating reaction is an air atmosphere or a protective atmosphere, further preferably a protective atmosphere, such as nitrogen, argon or the like.
  7. 7. The method of claim 6, wherein the atmosphere of the heating reaction is a protective atmosphere.
  8. 8. The method according to claim 1 or 2, wherein the heating reaction temperature is 60-100 ℃ and the heating reaction time is not less than 18 h.
  9. 9. The method according to claim 1 or 2, wherein after the heating reaction, the reaction solution is extracted, dried and filtered, distilled, and then separated and purified by column chromatography.

Description

Method for dehalogenation reduction of electron-rich aryl halide Technical Field The invention relates to a method for dehalogenating and reducing electron-rich aryl halides into corresponding aromatic hydrocarbons, belonging to the technical field of fine chemical synthesis. Background Aryl halide dehalogenation reduction is the most basic and irreplaceable functional group conversion reaction in organic synthesis, industrial production, environmental management and medical materials, and according to the report of related literature, the following methods are currently used for the dehalogenation reduction of aryl halides into corresponding aromatic hydrocarbons: First, this is currently the most predominant reduction method, starting from aryl halides, by reduction of the aryl halide to the corresponding aryl in the presence of an equivalent reducing agent, transition metal catalyst, etc. But most of the reduction processes need hydrogen, the safety is not high, expensive transition metal is needed to participate, the economy is not high, and the target product has hidden danger of metal residue, 。 Second, starting from an aryl halide, the aryl halide is reduced to the corresponding aromatic hydrocarbon in the presence of an equivalent metal reducing agent. The active metal reducing agent is needed, the operation is more complex, the economy is not high, the metal solid waste can be generated, the environment is not friendly, the practicability is poor, 。 Third, starting from aryl halides, the aryl halides are reduced to the corresponding aromatic hydrocarbons by using special equipment, such as microwave reactors or photochemical reactors. However, this method requires the use of special equipment and expensive photocatalytic reagents, is not easy to scale up, is poorly viable and practical, 。 Disclosure of Invention In order to solve the problems existing in the reduction of the existing aromatic hydrocarbon halide into the corresponding aromatic hydrocarbon, the invention aims to provide the method which takes the low-cost and easily-obtained low-toxicity and safe phosphorous acid as the reducing agent to replace the traditional metal reducing agent, hydrogen and the like, and uses catalytic amount of iodine to replace transition metal catalysis to dehalogenate and reduce the electron-rich aryl halide into the corresponding aromatic hydrocarbon, so that the method avoids the use of expensive metal catalysts and equivalent metal reducing agents, and has the advantages of low production cost, low-cost and easily-obtained raw materials, simple reaction conditions, environmental protection and contribution to industrial production. In order to achieve the above purpose, the present invention adopts the following technical scheme: An electron-rich aryl halide dehalogenation reduction method uses aryl halide as raw material, and adopts heating reaction in the presence of phosphorous acid, iodine simple substance and solvent to obtain the corresponding aromatic compound, the reaction equation is shown in formula I: A formula I; wherein the aromatic ring in the aryl halide is an aromatic ring containing electron-rich substituent, the electron-rich substituent is one or more of hydrocarbon group, methoxy, amino, imino and amino, the substituted positions and the number are not limited and can be the same or different, the aromatic ring is benzene ring or naphthalene ring or benzene ring or naphthalene ring containing alkyl substituent, such as methyl, ethyl, isopropyl, tert-butyl and the like, and X is Cl, br or I. Preferably, the aryl halide is selected from one of the following structural formulas: 、、、、、、、、、、、 、。 Preferably, the molar ratio of the aryl halide to the phosphorous acid is 1:1-8, more preferably 1:2-5, the molar ratio of the aryl halide to the iodine simple substance is 1:0.01-1, more preferably 1:0.05-0.5, and the concentration of the aryl halide in the solvent is 0.2-1.0 mol/L. Preferably, the solvent is 1, 2-dichloroethane, chlorobenzene, chloroform, dichloromethane, benzene, or toluene. Preferably, the atmosphere of the heating reaction is an air atmosphere or a protective atmosphere, and more preferably a protective atmosphere such as nitrogen, argon, or the like. Preferably, the heating reaction temperature is 60-100 ℃, and the heating reaction time is not less than 18 h. Preferably, after the heating reaction is finished, the reaction liquid is extracted, dried, filtered, steamed in a rotary way and then separated and purified by column chromatography. The invention has the beneficial effects that: The invention provides a dehalogenation reduction method of an electron-rich aryl halide, which is low in cost, easy to obtain, low in toxicity and safe, and the defect that the prior main stream method needs to use an expensive transition metal catalyst and an equivalent metal reagent to participate is directly avoided. The method takes the low-cost low-toxicity and relatively stable phosphoro