A method for preparing an unsymmetrical azobenzene compound

Abstract

The application discloses a preparation method of an asymmetric azobenzene compound; the method comprises the following steps: mixing a compound 1, a compound 2, an oxidizing agent and a solvent to react, and obtaining the asymmetric azobenzene compound; the asymmetric azobenzene compound is synthesized by using the compound 1 phenylhydrazine and the compound 2 phenylboronic acid as raw materials through a one-pot method, the complicated steps of separating and purifying the intermediate in traditional multi-step synthesis are avoided, the operation process is obviously simplified, and the reaction period is shortened. Meanwhile, the synthesis method has good functional group compatibility and high atom economy, and the synthesis efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for preparing an asymmetric azobenzene compound. Background Technology

[0002] Asymmetric azobenzenes, as a key class of N=N bond-containing aromatic compounds, have wide applications in organic dyes, optoelectronic functional materials, and drug molecules. However, their synthesis still faces significant challenges: the traditional Baeyer-Mills reaction requires strong acid conditions, has poor compatibility with electron-deficient substrates, and results in low yields; while coupling strategies based on azo precursors (such as diazonium salts and arylhydrazines) have made some progress, they generally suffer from poor substrate stability, require excess metal catalysts or strong bases, and have harsh reaction conditions, which limit their universal application in structure diversity-oriented synthesis.

[0003] Therefore, it is necessary to develop a new method for preparing asymmetric azobenzene compounds. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes a method for preparing asymmetric azobenzene compounds, which has high atom economy, higher synthesis efficiency, and good functional group tolerance.

[0005] According to a first aspect of the present invention, a method for preparing an asymmetric azobenzene compound is provided, comprising the following steps: Compound 1, compound 2, oxidant and solvent are mixed and reacted to obtain the asymmetric azobenzene compound; The structural formulas of compound 1, compound 2, and the asymmetric azobenzene compound are as follows: , , ; X1, X2, and X3 are each independently selected from C or N; R1 and R2 are one or more substituents, each independently selected from H and C. 1~6 alkyl, C 1~6 Alkyl groups, halogen C 1~6 alkyl halogenates.

[0006] According to a preferred embodiment of the present invention, the molar ratio of compound 1 to compound 2 is 1:(1 to 5). For example, it includes subranges of 1:1, 1:2, 1:3, 1:4, 1:5, or any two of the above ratios.

[0007] According to a preferred embodiment of the present invention, the oxidant includes at least one selected from 2-iodobenzoic acid, iodobenzene acetate, iodobenzene iodide, [bis(trifluoroacetoxy)iodine], tert-butyl hydroperoxide, N-fluorobenzenesulfonylimide, and m-chloroperoxybenzoic acid.

[0008] According to a preferred embodiment of the present invention, the reaction temperature is 60~120°C. For example, it includes 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, or any sub-range consisting of two of the above values.

[0009] According to a preferred embodiment of the present invention, the reaction time is 10-12 hours. For example, it includes 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, or any sub-range consisting of two of the above values.

[0010] According to a preferred embodiment of the present invention, the molar ratio of compound 1 to the oxidant is 1:(2-4). For example, it includes subranges of 1:2, 1:2.5, 1:3, 1:3.5, 1:4, or any two of the above ratios.

[0011] According to a preferred embodiment of the present invention, the solvent includes at least one selected from N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, dichloroethane, toluene, water, and 2,2,2-trifluoroethanol.

[0012] According to a preferred embodiment of the present invention, R1 is one or more substituents, each independently selected from H, C 1~6 alkyl, C 1~6 alkoxy, halogen, C 1~6 alkyl halogenates.

[0013] According to a preferred embodiment of the present invention, R2 is one or more substituents, each independently selected from H and C. 1~6 alkyl, C 1~6 alkoxy, halogen, C 1~6 alkyl halogenates.

[0014] According to a preferred embodiment of the present invention, the reaction is further comprising a purification step after completion.

[0015] According to a preferred embodiment of the present invention, the purified eluent is a mixed solution of petroleum ether, dichloromethane and ethyl acetate.

[0016] The method for preparing an asymmetric azobenzene compound according to an embodiment of the present invention has at least the following beneficial effects: This invention utilizes compounds 1 and 2 as starting materials to synthesize asymmetric azobenzene compounds in a one-pot process, avoiding the cumbersome steps of separating and purifying intermediates required in traditional multi-step synthesis. This significantly simplifies the operation process and shortens the reaction cycle. Furthermore, the reaction exhibits high atom economy, greatly improving the synthesis efficiency.

[0017] The preparation method of the present invention has good substrate universality and functional group tolerance, and can conveniently introduce a variety of different substituents to efficiently construct a library of structurally diverse asymmetric azobenzene compounds.

[0018] The phenylhydrazine-phenylboronic acid N=N coupling / rearrangement tandem reaction strategy established in this invention can efficiently construct a series of structurally diverse asymmetric azobenzene compounds under mild conditions, aligning with the principles of green chemistry. Gram-scale experiments and subsequent derivatization applications such as Sonogashira coupling, Suzuki coupling, and N-propytylation further confirm that the obtained asymmetric azobenzenes can serve as multifunctional synthetic building blocks for the modular construction of functionalized azo materials. Given the wide applications of asymmetric azobenzenes in organic dyes, optoelectronic functional materials, and drug molecule design, this invention provides a new technical route for the green and efficient synthesis of functional azo materials, possessing significant synthetic chemistry application value and industrial transformation potential.

[0019] Definitions and general terms “C 1-6 "alkyl" indicates an alkyl group with a total number of 1-6 carbon atoms, including C64. 1-6 straight-chain alkyl, C 1-6 Branched alkyl groups and C 3-6 The cycloalkyl group can be, for example, a straight-chain alkyl group with a total number of carbon atoms of 1, 2, 3, 4, 5 or 6, a branched-chain alkyl group with a total number of carbon atoms of 1, 2, 3, 4, 5 or 6, or a cycloalkyl group with a total number of carbon atoms of 3, 4, 5 or 6, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, cyclopropyl, methylcyclopropyl, ethylcyclopropyl, cyclopentyl, methylcyclopentyl, cyclohexyl, etc.

[0020] “C 1~6 "Halogenated alkyl" means that at least one H atom on the carbon atom is replaced by any halogen.

[0021] “C 1-6 "alkoxy group" refers to an alkoxy group with a total number of 1-6 carbon atoms, including C64 and C64. 1-6 straight-chain alkoxy, C 1-6 Branched alkoxy groups and C 2-6The cycloalkoxy group can be, for example, a straight-chain alkoxy group with a total number of carbon atoms of 1, 2, 3, 4, 5 or 6, a branched-chain alkoxy group with a total number of carbon atoms of 1, 2, 3, 4, 5 or 6, or a cycloalkoxy group with a total number of carbon atoms of 2, 3, 4, 5 or 6, such as methoxy, ethoxy, n-propoxy, isopropoxy, etc.

[0022] "Halogen" includes any one or more of fluorine, chlorine, bromine, and iodine.

[0023] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0024] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0025] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0026] Example 1 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3aa. The yield of this preparation method was 76%, and the compound was an orange solid with a purity of 99%.

[0027] The synthetic route is as follows:

[0028] The obtained product 3aa is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.96 (d, J = 7.5 Hz, 4H), 7.56 (t, J = 7.4 Hz, 4H), 7.53 – 7.49(m, 2H); 13C NMR (126 MHz, Chloroform- d ) d 152.7, 131.0, 129.1, 122.9. Example 2 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol / L p-methylphenylhydrazine, 0.2 mmol / L phenylboronic acid, 0.4 mmol / L 2-iodobenzoic acid, and 2 mL / L toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3ba. The yield of this preparation method was 73%, and the compound was an orange solid with a purity of 99%.

[0029] The synthetic route is as follows:

[0030] The obtained product 3ba is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.93 (d, J = 7.5 Hz, 2H), 7.87 (d, J = 8.2 Hz, 2H), 7.54 (t, J =7.4 Hz, 2H), 7.49 (t, J = 7.2 Hz, 1H), 7.35 (d, J = 7.8 Hz, 2H), 2.47 (s, 3H); 13 CNMR (126 MHz, Chloroform- d ) d 152.7, 150.8, 141.6, 130.7, 129.8, 129.1, 122.9, 122.7, 21.5. Example 3 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol / L p-ethylphenylhydrazine, 0.2 mmol / L phenylboronic acid, 0.4 mmol / L 2-iodobenzoic acid, and 2 mL / L toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ca. The yield of this preparation method was 68%, and the compound was an orange solid with a purity of 99%.

[0031] The synthetic route is as follows:

[0032] The obtained product 3ca is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.96 (d, J = 7.8 Hz, 2H), 7.91 (d, J = 8.2 Hz, 2H), 7.56 (t, J =7.5 Hz, 2H), 7.50 (t, J = 7.3 Hz, 1H), 7.39 (d, J = 8.1 Hz, 2H), 2.78 (q, J =7.6 Hz, 2H), 1.33 (t, J = 7.5 Hz, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.8, 151.0, 147.9, 130.7, 129.1, 128.6, 123.0, 122.8, 28.9, 15.5. Example 4 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol / L p-tert-butylphenylhydrazine, 0.2 mmol / L phenylboronic acid, 0.4 mmol / L 2-iodobenzoic acid, and 2 mL / L toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. oThe reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3da. The yield of this preparation method was 72%, and the compound was an orange solid with a purity of 99%.

[0033] The synthetic route is as follows:

[0034] The obtained product 3da is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.96 (d, J = 7.5 Hz, 2H), 7.92 (d, J = 8.6 Hz, 2H), 7.59 (d, J =8.7 Hz, 2H), 7.55 (d, J = 7.7 Hz, 2H), 7.50 (t, J = 7.2 Hz, 1H), 1.42 (s, 9H); 13 C NMR (126 MHz, Chloroform- d ) d 154.6, 152.8, 150.7, 130.7, 129.1, 126.1, 122.8, 122.6, 35.1, 31.3. Example 5 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol p-methoxyphenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ea. The yield of this preparation method was 42%, and the compound was an orange solid with a purity of 99%.

[0035] The synthetic route is as follows:

[0036] The obtained product 3ea is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.96 (d, J = 8.9 Hz, 2H), 7.92 – 7.89 (m, 2H), 7.53 (t, J = 7.5Hz, 2H), 7.47 (d, J = 7.2 Hz, 1H), 7.05 (d, J = 8.9 Hz, 2H), 3.92 (s, 3H); 13 CNMR (126 MHz, Chloroform- d ) d 162.1, 152.8, 147.0, 130.4, 129.1, 124.8, 122.6, 114.2, 55.6. Example 6 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol p-fluorophenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3fa. The yield of this preparation method was 71%, and the compound was an orange solid with a purity of 99%.

[0037] The synthetic route is as follows:

[0038] The obtained product 3fa is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d8.03 – 7.94 (m, 4H), 7.59 – 7.50 (m, 3H), 7.24 (t, J = 8.6 Hz, 2H); 13 C NMR (126 MHz, Chloroform- d ) d 164.4 (d, J = 251.9 Hz), 152.5, 149.2 (d, J =2.9 Hz), 131.1, 129.2, 124.9 (d, J = 8.9 Hz), 122.9, 116.1 (d, J = 22.9 Hz); 19 FNMR (471 MHz, Chloroform- d ) d -109.28. Example 7 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol p-chlorophenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was stirred in air at C for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ga. The yield of this preparation method was 66%, and the compound was an orange solid with a purity of 99%.

[0039] The synthetic route is as follows:

[0040] The obtained product 3ga is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.94 (d, J = 7.2 Hz, 2H), 7.91 (d, J = 8.6 Hz, 2H), 7.55 (t, J =7.2 Hz, 2H), 7.52 (d, J= 8.7 Hz, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.5, 151.0, 136.9, 131.3, 129.4, 129.2, 124.2, 123.0. Example 8 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol p-iodophenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ha. The yield of this preparation method was 65%, and the compound was an orange solid with a purity of 99%.

[0041] The synthetic route is as follows:

[0042] The obtained product 3ha is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.97 – 7.94 (m, 2H), 7.89 (d, J = 8.6 Hz, 2H), 7.69 (d, J = 8.6Hz, 2H), 7.54 (dd, J = 10.0, 7.3 Hz, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.5, 151.9, 138.4, 131.4, 129.2, 124.5, 123.0, 97.7. Example 9 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol / L p-trifluoromethylphenylhydrazine, 0.2 mmol / L phenylboronic acid, 0.4 mmol / L 2-iodobenzoic acid, and 2 mL / L toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ia. The yield of this preparation method was 63%, and the compound was an orange solid with a purity of 99%.

[0043] The synthetic route is as follows:

[0044] The obtained product 3ia is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (400 MHz, Chloroform- d ) d 8.03 (d, J = 8.2 Hz, 2H), 7.99 (dd, J = 7.8, 1.9 Hz, 2H), 7.81(d, J = 8.3 Hz, 2H), 7.57 (d, J = 6.6 Hz, 3H); 13 C NMR (101 MHz, Chloroform- d ) d 154.5, 152.4, 132.2 (q, J = 32.5 Hz), 131.8, 129.2, 128.0, 126.3 (q, J = 3.8Hz), 124.0 (d, J = 272.3 Hz), 123.1 (d, J = 15.9 Hz); 19 F NMR (377 MHz, Chloroform- d ) d -62.53. Example 10 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol m-chlorophenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3ja. The yield of this preparation method was 58%, and the compound was an orange solid with a purity of 99%.

[0045] The synthetic route is as follows:

[0046] The obtained product 3ja is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.98 – 7.94 (m, 3H), 7.89 – 7.87 (m, 1H), 7.58 – 7.53 (m, 3H),7.48 (dd, J = 4.9, 2.0 Hz, 2H); 13 C NMR (126 MHz, Chloroform- d ) d 153.5, 152.4, 135.2, 131.6, 130.7, 130.2, 129.2, 123.1, 122.5, 121.8. Example 11 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol m-isopropylphenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3ka. The yield of this preparation method was 61%, and the compound was an orange solid with a purity of 99%.

[0047] The synthetic route is as follows:

[0048] The obtained product at 3 ka is an orange solid, and its 1H and 1C spectral density structural characterization data are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.98 (d, J = 7.7 Hz, 2H), 7.87 (s, 1H), 7.80 (d, J = 7.7 Hz, 1H), 7.57 (t, J = 7.4 Hz, 2H), 7.54 – 7.47 (m, 2H), 7.40 (d, J = 7.4 Hz, 1H), 3.08 (hept, J = 6.9 Hz, 1H), 1.39 (s, 3H), 1.37 (s, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.9, 152.8, 150.1, 130.9, 129.4, 129.1, 129.1, 122.8, 121.1, 120.3, 34.2, 24.0. Example 12 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol m-tert-butylphenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3la. The yield of this preparation method was 53%, and the compound was an orange solid with a purity of 99%.

[0049] The synthetic route is as follows:

[0050] The obtained product 3la is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1H NMR (500 MHz, Chloroform- d ) d 8.04 (d, J = 2.0 Hz, 1H), 7.97 (d, J = 8.0 Hz, 2H), 7.78 (d, J =7.6 Hz, 1H), 7.56 (t, J = 6.3 Hz, 3H), 7.50 (q, J = 7.9 Hz, 2H), 1.45 (s, 9H); 13 C NMR (126 MHz, Chloroform- d ) d 152.8, 152.7, 152.4, 130.9, 129.1, 128.8, 128.2, 122.8, 121.0, 119.2, 35.0, 31.4. Example 13 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol o-iodophenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3ma. The yield of this preparation method was 42%, and the compound was an orange solid with a purity of 99%.

[0051] The synthetic route is as follows:

[0052] The obtained product 3ma is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 8.06 (t, J = 8.2 Hz, 3H), 7.68 (dd, J = 8.0, 1.7 Hz, 1H), 7.56(dt, J= 13.0, 6.8 Hz, 3H), 7.46 (t, J = 7.6 Hz, 1H), 7.20 (t, J = 7.3 Hz, 1H); 13 CNMR (126 MHz, Chloroform- d ) d 152.3, 151.3, 139.9, 132.3, 131.7, 129.3, 129.0, 123.6, 117.4, 102.6. Example 14 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol o-isopropylphenylhydrazine, 0.2 mmol phenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3na. The yield of this preparation method was 25%, and the compound was an orange solid with a purity of 99%.

[0053] The synthetic route is as follows:

[0054] The obtained product 3na is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.97 (d, J = 7.6 Hz, 2H), 7.66 (d, J = 7.6 Hz, 1H), 7.57 (t, J =7.4 Hz, 2H), 7.49 (p, J = 7.3 Hz, 3H), 7.34 – 7.29 (m, 1H), 4.15 (hept, J = 7.0Hz, 1H), 1.40 (s, 3H), 1.38 (s, 3H); 13 C NMR (126 MHz, Chloroform- d) d 153.1,149.7, 148.0, 131.3, 130.8, 129.1, 126.4, 126.3, 123.0, 115.3, 27.8, 23.9. Example 15 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol of 3,4-dimethylphenylhydrazine, 0.2 mmol of phenylboronic acid, 0.4 mmol of 2-iodobenzoic acid, and 2 mL of toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3oa. The yield of this preparation method was 52%, and the compound was an orange solid with a purity of 99%.

[0055] The synthetic route is as follows:

[0056] The obtained product 3oa is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.96 (d, J = 7.7 Hz, 2H), 7.77 (s, 1H), 7.75 (d, J = 7.9 Hz, 1H), 7.56 (t, J = 7.6 Hz, 2H), 7.50 (t, J = 7.1 Hz, 1H), 7.32 (d, J = 7.9 Hz,1H), 2.41 (s, 3H), 2.38 (s, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.8, 151.1, 140.4, 137.5, 130.7, 130.3, 129.1, 123.5, 122.7, 121.0, 20.0. Example 16 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol of 3,5-dimethylphenylhydrazine, 0.2 mmol of phenylboronic acid, 0.4 mmol of 2-iodobenzoic acid, and 2 mL of toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3pa. The yield of this preparation method was 47%, and the compound was an orange solid with a purity of 99%.

[0057] The synthetic route is as follows:

[0058] The obtained product 3pa is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.97 (d, J = 7.7 Hz, 2H), 7.61 (s, 2H), 7.56 (t, J = 7.5 Hz, 2H), 7.51 (t, J = 7.2 Hz, 1H), 7.17 (s, 1H), 2.47 (s, 6H); 13 C NMR (126 MHz, Chloroform- d ) d 152.9, 152.8, 138.8, 132.8, 130.9, 129.1, 122.8, 120.7, 21.3. Example 17 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol of 2,4-dibromophenylhydrazine, 0.2 mmol of phenylboronic acid, 0.4 mmol of 2-iodobenzoic acid, and 2 mL of toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3qa. The yield of this preparation method was 28%, and the compound was an orange solid with a purity of 99%.

[0059] The synthetic route is as follows:

[0060] The obtained product 3qa is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 8.01 (dd, J = 7.6, 2.2 Hz, 2H), 7.85 (d, J = 2.5 Hz, 1H), 7.62(d, J = 8.5 Hz, 1H), 7.56 (d, J = 6.7 Hz, 3H), 7.43 (dd, J = 8.4, 2.4 Hz, 1H); 13 CNMR (126 MHz, Chloroform- d ) d 152.3, 150.0, 134.9, 134.4, 132.2, 129.3, 124.6, 123.7, 122.1, 121.0. Example 18 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol of 2,5-dibromophenylhydrazine, 0.2 mmol of phenylboronic acid, 0.4 mmol of 2-iodobenzoic acid, and 2 mL of toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ra. The yield of this preparation method was 31%, and the compound was an orange solid with a purity of 99%.

[0061] The synthetic route is as follows:

[0062] The obtained product 3ra is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1);1 H NMR (500 MHz, Chloroform- d ) d 8.01 (dd, J = 7.6, 2.2 Hz, 2H), 7.85 (d, J = 2.3 Hz, 1H), 7.64(d, J = 8.5 Hz, 1H), 7.58 – 7.55 (m, 3H), 7.46 (dd, J = 8.5, 2.4 Hz, 1H); 13 C NMR (126 MHz, Chloroform- d ) d 152.4, 150.1, 134.9, 134.4, 132.2, 129.3, 124.5, 123.7, 122.0, 121.0. Example 19 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol of 2-hydrazidepyridine, 0.2 mmol of phenylboronic acid, 0.4 mmol of 2-iodobenzoic acid, and 2 mL of toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3sa. The yield of this preparation method was 43%, and the compound was an orange solid with a purity of 99%.

[0063] The synthetic route is as follows:

[0064] The obtained product 3sa is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 8.79 (s, 1H), 8.08 (s, 2H), 7.91 (d, J = 32.6 Hz, 2H), 7.56 (s, 3H), 7.44 (s, 1H); 13 C NMR (126 MHz, Chloroform-d ) d 162.8, 152.4, 149.5, 138.4, 132.2, 129.2, 125.3, 123.6, 115.7. Example 20 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol p-methylphenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ab. The yield of this preparation method was 63%, and the compound was an orange solid with a purity of 99%.

[0065] The synthetic route is as follows:

[0066] The obtained product 3ab is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.93 (d, J = 7.3 Hz, 2H), 7.86 (d, J = 8.3 Hz, 2H), 7.54 (t, J =7.4 Hz, 2H), 7.49 (d, J = 7.2 Hz, 1H), 7.35 (d, J = 8.0 Hz, 2H), 2.47 (s, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.7, 150.8, 141.6, 130.2, 129.8, 129.1, 122.9, 122.7, 21.5. Example 21 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol p-methoxyphenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ac. The yield of this preparation method was 56%, and the compound was an orange solid with a purity of 99%.

[0067] The synthetic route is as follows:

[0068] The obtained product 3ac is an orange solid, and its 1H and 1C spectral density structural characterization data are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 8.00 (d, J = 9.0 Hz, 2H), 7.96 (d, J = 7.4 Hz, 2H), 7.56 (t, J =7.5 Hz, 2H), 7.49 (t, J = 7.3 Hz, 1H), 7.06 (d, J = 9.0 Hz, 2H), 3.90 (s, 3H); 13 CNMR (126 MHz, Chloroform- d ) d 162.1, 152.8, 147.1, 130.5, 129.1, 124.9, 122.7, 114.3, 55.6. Example 22 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol p-chlorophenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ad. The yield of this preparation method was 54%, and the compound was an orange solid with a purity of 99%.

[0069] The synthetic route is as follows:

[0070] The obtained product 3ad is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.95 (d, J = 7.3 Hz, 2H), 7.91 (d, J = 8.6 Hz, 2H), 7.55 (d, J =7.7 Hz, 2H), 7.52 (d, J = 8.7 Hz, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.5, 151.0, 136.9, 131.3, 129.4, 129.2, 124.2, 123.0. Example 23 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol p-bromophenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ae. The yield of this preparation method was 58%, and the compound was an orange solid with a purity of 99%.

[0071] The synthetic route is as follows:

[0072] The obtained product 3ae is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.94 (d,J = 6.5 Hz, 2H), 7.83 (d, J = 8.5 Hz, 2H), 7.68 (d, J =8.6 Hz, 2H), 7.58 – 7.50 (m, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.5, 151.3, 132.4, 131.4, 129.2, 125.4, 124.4, 123.0. Example 24 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol p-trifluoromethylphenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3af. The yield of this preparation method was 49%, and the compound was an orange solid with a purity of 99%.

[0073] The synthetic route is as follows:

[0074] The obtained product 3af is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: 1 H NMR (500 MHz, Chloroform- d ) d 8.03 (d, J = 8.0 Hz, 2H), 7.99 (dd, J =8.0, 1.8 Hz, 2H), 7.81 (d, J = 8.3 Hz, 2H), 7.59 – 7.54 (m, 3H); 13 C NMR (126MHz, Chloroform- d ) d 154.4, 152.4, 132.2 (d, J = 32.3 Hz), 131.9, 129.2, 126.3(q, J = 3.8 Hz), 123.2, 123.0; 19F NMR (471 MHz, Chloroform- d ) d -62.51. Example 25 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol m-methylphenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3ag. The yield of this preparation method was 46%, and the compound was an orange solid with a purity of 99%.

[0075] The synthetic route is as follows:

[0076] The obtained product 3ag was an orange solid, and its 1H and 1C spectral density structural characterization data are as follows: 1 H NMR (500 MHz, Chloroform- d ) d 7.98 – 7.94 (m, 2H), 7.77 (s, 2H),7.56 (t, J = 7.4 Hz, 2H), 7.50 (t, J = 7.2 Hz, 1H), 7.47 – 7.42 (m, 1H), 7.33(d, J = 7.4 Hz, 1H), 2.50 (s, 3H); 13 C NMR (126 MHz, Chloroform- d ) d 152.8, 152.7, 139.0, 131.8, 130.9, 129.1, 128.9, 123.0, 122.8, 120.5, 21.4. Example 26 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol m-chlorophenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. oThe reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ah. The yield of this preparation method was 42%, and the compound was an orange solid with a purity of 99%.

[0077] The synthetic route is as follows:

[0078] The obtained product 3ah is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 7.98 – 7.92 (m, 3H), 7.87 (d, J = 6.1 Hz, 1H), 7.55 (dd, J =10.1, 7.3 Hz, 3H), 7.49 (d, J = 6.1 Hz, 2H); 13 C NMR (126 MHz, Chloroform- d ) d 153.5, 152.4, 135.2, 131.6, 130.7, 130.2, 129.2, 123.1, 122.4, 121.8. Example 27 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol o-iodophenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3ai. The yield of this preparation method was 37%, and the compound was an orange solid with a purity of 99%.

[0079] The synthetic route is as follows:

[0080] The obtained product 3ai is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f= 0.48 (petroleum ether: ethyl acetate = 50: 1); 1 H NMR (500 MHz, Chloroform- d ) d 8.06 (t, J = 8.1 Hz, 3H), 7.68 (dd, J = 8.0, 1.7 Hz, 1H), 7.56(dt, J = 13.0, 6.8 Hz, 3H), 7.48 – 7.43 (m, 1H), 7.20 (td, J = 7.5, 1.7 Hz, 1H); 13 C NMR (126 MHz, Chloroform- d ) d 152.34, 151.32, 139.88, 132.26, 131.65, 129.25, 128.96, 123.63, 117.39, 102.63. Example 28 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol 3,4-dimethylphenylboronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under C conditions with stirring in air for 12 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3aj. The yield of this preparation method was 29%, and the compound was an orange solid with a purity of 99%.

[0081] The synthetic route is as follows:

[0082] The obtained product 3aj is an orange solid, and its 1H and 1C spectral density structural characterization data are as follows: R f= 0.48 (petroleum ether: ethyl acetate = 50: 1);1H NMR (500 MHz, Chloroform-d) δ 8.01 – 7.97 (m, 2H), 7.80 (s, 1H), 7.79 – 7.76 (m, 1H), 7.57(t, J = 7.5 Hz, 2H), 7.51 (t, J = 7.3 Hz, 1H), 7.34 (d, J = 7.9 Hz, 1H), 2.42(s, 3H), 2.39 (s, 3H); 13C NMR (126 MHz, Chloroform-d) δ 152.84, 151.17,140.38, 137.49, 130.70, 130.35, 129.13, 123.59, 122.78, 121.00, 19.97. Example 29 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol pyridine-4-boronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain the crude product. The crude product was purified by column chromatography to obtain compound 3ak. The yield of this preparation method was 37%, and the compound was an orange solid with a purity of 99%.

[0083] The synthetic route is as follows:

[0084] The obtained product 3ak is an orange solid, and its structural characterization data in proton and carbon spectroscopy are as follows: R f= 0.48 (petroleum ether: ethyl acetate = 50: 1);1H NMR (500 MHz, Chloroform-d) δ 9.28 (s, 1H), 8.78 (s, 1H), 8.18 (d, J = 8.1 Hz, 1H), 7.97(dd, J = 8.0, 1.8 Hz, 2H), 7.64 – 7.47 (m, 4H); 13C NMR (126 MHz, Chloroform-d) δ 152.49, 151.57, 147.28, 131.81, 129.23, 126.97, 123.11. Example 30 This example provides a method for preparing an asymmetric azobenzene compound. The reaction equation and steps are as follows: 0.2 mmol phenylhydrazine, 0.2 mmol pyridine-3-boronic acid, 0.4 mmol 2-iodobenzoic acid, and 2 mL toluene were sequentially added to a 25 mL Schlenk tube and incubated at 100 °C. o The reaction was carried out under air at C for 12 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature to obtain a crude product. The crude product was purified by column chromatography to obtain compound 3al. The yield of this preparation method was 32%, and the compound was an orange solid with a purity of 99%.

[0085] The synthetic route is as follows:

[0086] The obtained product 3al is an orange solid, and its structural characterization data of proton and carbon spectra are as follows: R f = 0.48 (petroleum ether: ethyl acetate = 50: 1);1H NMR (500 MHz, Chloroform-d) δ 9.29 (s, 1H), 8.79 (s, 1H), 8.18 (d, J = 8.1 Hz, 1H), 7.97(d, J = 6.2 Hz, 2H), 7.56 (q, J = 7.5, 6.9 Hz, 4H); 13C NMR (126 MHz, Chloroform-d) δ 152.49, 151.56, 147.28, 131.80, 129.23, 126.94, 123.11,120.46. The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing an asymmetric azobenzene compound, characterized in that, Includes the following steps: Compound 1, compound 2, oxidant and solvent are mixed and reacted to obtain the asymmetric azobenzene compound; The structural formulas of compound 1, compound 2, and the asymmetric azobenzene compound are as follows: 、 、 ； X1, X2, and X3 are each independently selected from C or N; R1 and R2 are one or more substituents, each independently selected from H and C. 1~6 alkyl, C 1~6 alkoxy groups, halogen C 1~6 alkyl halogenates.

2. The preparation method according to claim 1, characterized in that, The molar ratio of compound 1 to compound 2 is 1:(1 to 5).

3. The preparation method according to claim 1, characterized in that, The oxidant includes at least one of 2-iodobenzoic acid, iodobenzene acetate, iodobenzene iodide, [bis(trifluoroacetoxy)iodine], tert-butyl hydroperoxide, N-fluorobenzenesulfonylimide, and m-chloroperoxybenzoic acid.

4. The preparation method according to claim 1, characterized in that, The reaction temperature is 60~120℃.

5. The preparation method according to claim 1, characterized in that, The reaction time is 10-12 hours.

6. The preparation method according to claim 1, characterized in that, The molar ratio of compound 1 to the oxidant is 1:(2-4).

7. The preparation method according to claim 1, characterized in that, The solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, dichloroethane, toluene, water, and 2,2,2-trifluoroethanol.

8. The preparation method according to claim 1, characterized in that, R1 is one or more substituents, each independently selected from H, C. 1~6 alkyl, C 1~6 alkoxy, halogen, C 1~6 alkyl halogenates.

9. The preparation method according to claim 1, characterized in that, R2 is one or more substituents, each independently selected from H, C. 1~6 alkyl, C 1~6 alkoxy, halogen, C 1~6 alkyl halogenates.

10. The preparation method according to claim 1, characterized in that, The reaction is followed by a purification step.

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