A copper-catalyzed halogen exchange method of halogenated arenes

Abstract

The application belongs to the field of organic synthesis and relates to a copper-catalyzed halogen exchange method of halogenated aromatic hydrocarbons. The method is that an imine shown in the following formula is used as a ligand, and copper is used to efficiently catalyze the exchange reaction between aryl halide and a halogen source to obtain a halogen exchange product, wherein the halogen source is at least one of an iodine source, a bromine source and a chlorine source. The halogen exchange catalytic system developed by the application has wide substrate applicability, a green and mild reaction system, and the iodine source, the bromine source and the chlorine source used are cheap and easy to obtain, and the application has good industrial application value.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis and relates to a method for preparing different haloaromatic hydrocarbons by copper-catalyzed aryl halogen exchange. Background Technology

[0002] Aryl halides are important intermediates in many pharmaceutical compounds and are widely used in various transition metal-catalyzed cross-coupling reactions. From the dissociation energies of the carbon-halogen bond: C-Cl (351.8 KJ / mol) > C-Br (292.9 KJ / mol) > CI (221.8 KJ / mol), it can be seen that chlorobromine-iodine-substituted aryl halides exhibit significant differences in reactivity. In common chemical reactions, the reactivity differences between halides allow for precise control of the reaction conversion direction by selecting different halides. Therefore, achieving the interconversion of halogen atoms in aryl halides is essential. In 2005, Henri et al. (Chemistry–A European Journal 11 (2005) 2483-2492) reported the exchange of bromine to iodine using 1,10-phenanthroline as a ligand and CuI as a catalyst precursor, but the reaction conversion rate was low, the applicability was limited, and the reaction time required 48 hours. In 2010, Hong Wu et al. (Organic Letters 12 (2010) 1192-1195) reported a Cu(I) catalytic conversion of arylboronic acid to aryl chloride using NCS as the chlorine source. However, the reaction required an excess of copper salt (3.5 equivalents), which limited its industrial application. In 2016, Feng et al. (Catalysis Today 274 (2016) 129-132) reported a halogen exchange method using L-proline as a ligand, Cu2O as a catalyst precursor, and tetramethylammonium chloride as the chlorine source. The conversion rate was good, but the reaction required a high temperature of 110°C for more than 30 hours. Therefore, the current halogen exchange reaction of aryl halides still has some drawbacks and limitations: complex reaction conditions, expensive ligands, low conversion rates, and significant limitations for aryl halides. Based on this, this invention proposes a novel copper-catalyzed method for aryl halogen exchange to prepare different halogenated aromatic hydrocarbons. This invention has a very wide range of applications, applicable to the vast majority of commonly used aryl halides, achieving efficient conversions between aryl iodides, aryl bromides, and aryl chlorides. It is a green, safe, and practical new method for the efficient and widespread preparation of aryl halides. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of existing technologies and provide a copper-catalyzed method for the exchange of aryl halogens to prepare different haloaromatics. It also establishes a widely applicable, environmentally friendly, and green system. The method is simple to operate, uses inexpensive and readily available raw materials, has good substrate applicability, and achieves good yields.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A copper-catalyzed halogen exchange method for halogenated aromatic hydrocarbons, wherein the method uses an imine as a ligand, and copper efficiently catalyzes the exchange reaction between the aryl halide and a halogen source to obtain a halogen exchange product, wherein the halogen source is at least one of a chlorine source, a bromine source, and an iodine source.

[0006] Preferably, the reaction formula of the method is as follows:

[0007]

[0008] In formula (I), X 1 It is bromine or chlorine; X 2 It is chlorine, bromine, or iodine; YX 2 It is a brine source;

[0009] Ar is an aromatic compound containing an aromatic ring, wherein the aromatic ring is a C5-C12 aromatic ring with or without heteroatoms, and the heteroatoms are at least one of N, S, and O. More preferably, the aromatic ring includes, but is not limited to, benzene rings, biphenyl, naphthalene, diphenyl ketones, and heterocyclic structures such as pyridine, pyrazine, quinoline, thiophene, and furan containing N, S, and O heteroatoms.

[0010] R 1 The substituent is at any position on the aromatic ring, and the number of substituents is at least one. The substituents include, but are not limited to, at least one of hydrogen, C1-C6 alkyl, C1-C6 alkoxy, cyano, amino, carboxyl, hydroxyl, nitro, and halogen groups, wherein the halogen group includes at least one of fluorine, chlorine, bromine, and iodine; more preferably, the number of substituents on the aromatic ring is 1 to 3.

[0011] The imine structure is shown in formula (II), where R 2 It is at least one of hydrogen, C1-C6 alkyl, or phenyl containing at least one substituent, wherein the substituent is substituted at any position on the benzene ring, and the substituent on the phenyl is selected from at least one of H, halogen group, C1-C6 alkyl, C1-C6 alkoxy, or nitro, wherein the halogen group includes at least one of fluorine, chlorine, bromine, or iodine.

[0012] Preferably, the iodine source is at least one of sodium iodide, potassium iodide, tetrabutylammonium iodide, and tetramethylammonium iodide; the chlorine source is at least one of tetrabutylammonium chloride and tetramethylammonium chloride; and the bromine source is at least one of sodium bromide, potassium bromide, tetrabutylammonium bromide, and tetramethylammonium bromide. More preferably, the iodine source is sodium iodide, the chlorine source is tetramethylammonium chloride, and the bromine source is sodium bromide.

[0013] Preferably, the copper salt is a cuprous salt, including at least one of cuprous iodide, cuprous chloride, and cuprous bromide.

[0014] Preferably, the molar ratio of the aryl halide, halogen source, imine ligand, and copper salt is (20-30):(20-60):(1-2):1; more preferably, it is 20:40:2:1.

[0015] Preferably, the exchange reaction further includes a solvent, which is one or a mixture of two or more of the following solvents in any proportion: diethylene glycol, polyethylene glycol 2000, butanediol, N,N-dimethylformamide (DMF), 1,3-dimethyl-2-imidazolinone (DMI), and dimethylacetamide (DMAC); more preferably, diethylene glycol. The mass ratio of the aryl halide to the solvent is 1:(1-100); more preferably, 1:(15-30).

[0016] Preferably, the exchange reaction temperature is 90-180℃; more preferably, it is 140℃.

[0017] Preferably, the exchange reaction time is 2-6 hours; more preferably, it is 4 hours.

[0018] Preferably, the imine structure is as follows; more preferably, it is structure 1a:

[0019]

[0020] Preferably, the imine is synthesized from cyclohexanediamine and aldehyde / ketone compounds. Cyclohexanediamine and aldehyde / ketone compounds are added to a solvent, and the reaction yields the desired imine ligand. Compared to existing imine synthesis methods, the preparation method provided by this invention is simpler and milder, can be carried out at room temperature, and uses a green solvent.

[0021] Preferably, the molar ratio of cyclohexanediamine and aldehydes / ketones in the imine preparation reaction is 1:1.

[0022] (0.8-2.5); more preferably 1:1.05.

[0023] Preferably, the reaction temperature for preparing the imine is 20-100℃; more preferably, it is 30℃.

[0024] Preferably, the reaction time for preparing the imine is 1-5 hours; more preferably, it is 3 hours.

[0025] Preferably, the solvent for the imine preparation reaction is one or a mixture of two or more of water, ethanol, methanol, tetrahydrofuran, and toluene in any proportion; more preferably, it is water. The mass ratio of cyclohexanediamine to solvent is 1:(1-100); more preferably, it is 1:(15-30).

[0026] Preferably, the post-processing steps for the imine preparation reaction are as follows: after the reaction is completed, the solvent is removed under reduced pressure to precipitate solids, which are then slurried with petroleum ether and dried to obtain the desired ligand.

[0027] Preferably, the reaction may include a post-processing step, wherein the post-processing steps are as follows: after the reaction is completed, a certain amount of water is added to the reaction solution and extracted with ethyl acetate; the extract is dried and concentrated and then separated by column chromatography to obtain a purified and collected product.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] (1) The halogen exchange system developed in this invention has a wide substrate applicability and can realize arbitrary exchange between the three halogens: bromine, chlorine, and iodine.

[0030] (2) The halogen exchange system developed in this invention has simple reaction operation, is economical and inexpensive, has high ligand efficiency, and is industrially applicable. Detailed Implementation

[0031] The technical solution of the present invention will be further clearly and completely described below through specific embodiments. It should be understood that the embodiments described in this invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but they are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used in the examples are commercially available unless otherwise specified.

[0033] Example 1

[0034]

[0035] 0.785 g (1 eq) of bromobenzene and 0.562 g (1 eq) of chlorobenzene were added to a three-necked flask equipped with a stirrer, along with KI (1-3 eq), catalyst (0.05 eq), ligands 1a-7a (0.1 eq), and 15 ml of solvent. The reaction mixture was heated at a certain temperature for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was obtained by distillation. The target product was a yellow liquid. The specific reaction conditions and yields are shown in Table 1. The post-processing steps in this embodiment are applicable to other embodiments.

[0036] Table 1. Reactions under different conditions and yields

[0037]

[0038] The ligand structure is shown below:

[0039]

[0040] Products obtained from bromobenzene 1 The H NMR data characterization is as follows: 1 H NMR(400MHz,Chloroform-d)δ7.24-7.16(m,5H).

[0041] Example 2

[0042]

[0043] 0.935 g of 4-bromoanisole was added to a three-necked flask equipped with a stir bar, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 g of polyethylene glycol 2000 solvent. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 mL of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)). The target product was a pale yellow solid with a yield of 83%. The post-processing steps in this embodiment are applicable to other embodiments.

[0044] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ7.41 (d, J = 12 Hz, 2H), 6.46 (d, J = 8 Hz, 2H), 3.63 (s, 3H).

[0045] Example 3

[0046]

[0047] 0.860 g of 4-bromoaniline was added to a three-necked flask equipped with a stir bar, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)). The target product was a light gray solid with a yield of 86%. The post-processing steps in this embodiment are applicable to other embodiments.

[0048] Products obtained 1 The H NMR data characterization is as follows:1 H NMR (400MHz, Chloroform-d) δ7.41 (d, J = 12 Hz, 2H), 6.46 (d, J = 8 Hz, 2H), 3.63 (s, 2H).

[0049] Example 4

[0050]

[0051] 0.910 g of 2-bromobenzonitrile was added to a three-necked flask equipped with a stirrer, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)). The target product was a yellow solid with a yield of 75%. The post-processing steps in this embodiment are applicable to other embodiments.

[0052] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ7.85(d,J=7.9Hz,1H),7.45(d,J=7.9Hz,1H),7.27(t,J=7.9Hz,1H),6.94(t,J=7.9Hz,1H).

[0053] Example 5

[0054]

[0055] 0.785 g of 4-chloronitrobenzene was added to a three-necked flask equipped with a stir bar, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)). The target product was a yellow solid with a yield of 77%. The post-processing steps in this embodiment are applicable to other embodiments.

[0056] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ7.96-7.90 (m, 4H).

[0057] Example 6

[0058]

[0059] 0.815 g of 4-bromothiophene was added to a three-necked flask equipped with a stirrer, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was obtained by distillation. The target product was a yellow liquid with a yield of 73%. The post-processing steps in this embodiment are applicable to other embodiments.

[0060] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d): δ7.31 (d, J = 4Hz, 1H), 7.21 (s, J = 4Hz, 1H), 6.78-6.76 (m, 1H).

[0061] Example 7

[0062]

[0063] 0.995 g of 2-bromotrimethylbenzene was added to a three-necked flask equipped with a stirrer, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was obtained by distillation. The target product was a pale yellow liquid with a yield of 77%. The post-processing steps in this embodiment are applicable to other embodiments.

[0064] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ6.87(s,2H),2.41(s,6H),2.22(s,3H).

[0065] Example 8

[0066]

[0067] 1.005 g of 4-bromobenzoic acid was added to a three-necked flask equipped with a stir bar, along with 1.660 g of KI, 0.047 g of CuI, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)). The target product was a white solid with a yield of 85%. The post-processing steps in this embodiment are applicable to other embodiments.

[0068] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ13.14(br,0.79H),7.85(t,J=9.9Hz,2H),7.69(t,J=7.9Hz,2H).

[0069] Example 9

[0070]

[0071] 0.935 g of 4-bromoanisole was added to a three-necked flask equipped with a stirrer, along with 2.960 g of tetrabutylammonium chloride, 0.025 g of CuCl, 0.068 g of ligand 1a, and 15 ml of DMAC solvent. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was obtained by distillation. The target product was a colorless liquid with a yield of 82%. The post-processing steps in this embodiment are applicable to other embodiments.

[0072] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ7.26 (d, J = 12Hz, 2H), 6.84 (d, J = 8Hz, 2H), 3.78 (s, 3H).

[0073] Example 10

[0074]

[0075] 1.305 g of 4-bromobenzophenone was added to a three-necked flask equipped with a stir bar, along with 1.100 g of tetramethylammonium chloride, 0.025 g of CuCl, 0.068 g of ligand 1a, and 15 ml of butanediol solvent. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)). The target product was a white solid with a yield of 86%. The post-processing steps in this embodiment are applicable to other embodiments.

[0076] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d): δ7.78 (t, J = 7.0Hz, 4H), 7.61 (t, J = 7.4Hz, 1H), 7.51-7.45 (m, 4H).

[0077] Example 11

[0078]

[0079] 1.165 g of 4-bromobiphenyl was added to a three-necked flask equipped with a stirrer, along with 1.100 g of tetramethylammonium chloride, 0.025 g of CuCl, 0.068 g of ligand 1a, and 15 ml of DMAC solvent. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the target product was obtained by distillation. The target product was a colorless liquid with a yield of 78%. The post-processing steps in this embodiment are applicable to other embodiments.

[0080] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR(400MHz,Chloroform-d)δ7.62-7.56(m,4H),7.52-7.41(m,5H).

[0081] Example 12

[0082]

[0083] 81 g of bromobenzene was added to a three-necked flask equipped with a stirrer, along with 110 g of tetramethylammonium chloride, 2.475 g of CuCl, 6.8 g of ligand 1a, and 1 L of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 200 mL of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the product was obtained by distillation. The target product was a colorless liquid with a yield of 83%. The post-processing steps in this embodiment are applicable to other embodiments.

[0084] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR(400MHz,Chloroform-d)δ7.29-7.18(m,5H).

[0085] Example 13

[0086]

[0087] 0.862 g of 5-chlorosalicylic acid was added to a three-necked flask equipped with a stir bar, along with 1.030 g of sodium bromide, 0.035 g of CuBr, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried and purified by rapid column chromatography (mobile phase: petroleum ether / ethyl acetate (vv: 40–5:1)) to obtain the target product. The target product was a pale yellow solid with a yield of 78%. The post-processing steps in this embodiment are applicable to other embodiments.

[0088] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR (400MHz, Chloroform-d) δ10.39 (s, 1H), 8.06 (d, J = 2.4Hz, 1H), 7.62 (dd, J = 8.6, 2.4Hz, 1H), 6.94 (d, J = 9Hz, 1H), 5.72 (s, 1H).

[0089] Example 14

[0090]

[0091] 0.818 g of 6-chloroquinoline was added to a three-necked flask equipped with a stirrer, along with 1.030 g of sodium bromide, 0.035 g of CuBr, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the product was obtained by distillation. The target product was a yellow liquid with a yield of 85%. The post-processing steps in this embodiment are applicable to other embodiments.

[0092] Products obtained 1 The H NMR data characterization is as follows: 1 H NMR(400MHz,Chloroform-d)δ8.90(dd,J=4.4,1.8Hz,1H),8.07-8.03(m,1H),7.96(d ,J=6.0Hz,1H),7.96(s,1H),7.75(dd,J=9.0,2.2Hz,1H),7.42(dd,J=8.1,4.2Hz,1H),

[0093] Example 15

[0094]

[0095] 0.637 g of 2-chloroaniline was added to a three-necked flask equipped with a stirrer, along with 1.030 g of sodium bromide, 0.035 g of CuBr, 0.068 g of ligand 1a, and 15 ml of diethylene glycol. The reaction mixture was heated at 140 °C for 4 hours. After the reaction was complete, 20 ml of water was added, and the mixture was extracted with ethyl acetate. The extract was dried, and the product was obtained by distillation. The target product was a yellow liquid with a yield of 81%. The post-processing steps in this embodiment are applicable to other embodiments.

[0096] The obtained product was characterized by the following 1H NMR data: 1H NMR (400MHz, Chloroform-d) δ 7.42 (dd, J = 7.89, 1.76Hz, 1H), 7.11 (m, 1H), 6.75 (dd, J = 8.25, 1.74Hz, 1H), 6.64 (m, 1H).

[0097] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A copper-catalyzed halogen exchange method for aromatic halogens, characterized in that, The method involves using an imine as a ligand, and copper-catalyzed exchange reaction between an aryl halide and a halogen source to obtain a halogen exchange product, wherein: The halogen source is at least one of an iodine source, a chlorine source, and a bromine source; the iodine source is at least one of sodium iodide, potassium iodide, tetrabutylammonium iodide, and tetramethylammonium iodide; the chlorine source is at least one of tetrabutylammonium chloride and tetramethylammonium chloride; and the bromine source is at least one of sodium bromide, potassium bromide, tetrabutylammonium bromide, and tetramethylammonium bromide. The copper is a cuprous salt, selected from at least one of cuprous iodide, cuprous chloride, and cuprous bromide; The molar ratio of the aryl halide, halogen source, imine ligand, and cuprous salt is (20-30):(20-60):(1-2):1; The exchange reaction temperature is 90-180℃; The exchange reaction further includes a solvent, which is one or a mixture of two or more solvents in any proportion, namely diethylene glycol, polyethylene glycol 2000, butanediol, N,N-dimethylformamide, 1,3-dimethyl-2-imidazolinone, and dimethylacetamide. The structural formula of imine is shown below: ， The reaction formula for the method is as follows: ， In the formula, X 1 It is bromine or chlorine; X 2 It is chlorine, bromine, or iodine; YX 2 It is a brine source; R 1 It is a substituent at any position on the aromatic ring, and the number of substituents is at least one. The substituents are selected from at least one of hydrogen, C1-C6 alkyl, C1-C6 alkoxy, cyano, amino, carboxyl, hydroxyl, nitro, and halogen groups. Ar is a C5-C12 aromatic ring compound with or without heteroatoms, wherein the heteroatoms are at least one of N, S, and O.

2. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1, characterized in that, The imine is 1a.

3. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1, characterized in that, The iodine source is sodium iodide or potassium iodide, the chlorine source is tetramethylammonium chloride, and the bromine source is sodium bromide.

4. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1, characterized in that, The copper mentioned is cuprous iodide.

5. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1, characterized in that, The molar ratio of the aryl halide, halogen source, imine ligand, and copper salt is 20:40:2:

1.

6. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1, characterized in that, The solvent is diethylene glycol.

7. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1, characterized in that, The exchange reaction temperature is 140°C.

8. The method for halogen exchange of copper-catalyzed aromatic halogens according to claim 7, characterized in that, The exchange reaction time is 2-6 hours.

9. A method for halogen exchange of copper-catalyzed aromatic halogens according to claim 1 or 2, characterized in that, The imine is synthesized from cyclohexanediamine and aldehyde / ketone compounds. Cyclohexanediamine and aldehyde / ketone compounds are added to a solvent, and the reaction yields the desired imine compound.

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