A method for preparing a highly efficient selective oxidation system for thioethers and benzyl CH bonds

Abstract

The invention discloses a preparation method for a highly efficient selective oxidation system for thioethers and benzylic C-H bonds, trichloroacetonitrile (CCl3CN) being used as a green photosensitizer, and belongs to the technical field of organic synthetic chemistry. The specific steps are as follows: ① placing thioether compounds and trichloroacetonitrile in a reaction tube and adding methanol to dissolve them; ② placing alkylbenzene and benzyl ether compounds in a reaction tube and dissolving them in trichloroacetonitrile, and placing the reaction tube under ultraviolet light for irradiation to obtain corresponding oxidation products. The invention realizes the selective oxidation of thioethers and benzylic C-H bonds, which not only has high yield, wide application range of substrates, easy availability of raw materials, and good economy, but also has mild reaction conditions and is green and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the field of organic chemical synthesis, and in particular to a preparation method for a highly efficient selective oxidation system for thioether and benzyl CH bonds. Background Art

[0002] In recent years, visible light-driven chemical reactions have become a very powerful tool that can perform various functionalizations under mild reaction conditions. However, most visible light-mediated reaction systems require the addition of metal photocatalysts, such as ruthenium, iridium, uranium complexes, etc. These photocatalysts often contain toxic heavy metal compounds and are generally expensive. Therefore, from the perspective of environmental protection and economy, it is very necessary to develop a class of visible light-driven chemical reactions catalyzed by green photocatalysts.

[0003] Sulfoxides are widely present in pharmaceuticals and agricultural products, and are usually synthesized by sulfide oxidation. In existing literature reports, how to avoid excessive oxidation of thioethers to sulfones is a big problem. Usually, sulfoxides are active groups in drug molecules, and even a small amount of sulfone will greatly affect the activity of the drug. Therefore, an oxidation system that can selectively oxidize thioethers to sulfoxides is of great significance in the fields of drug synthesis, agrochemicals, polymers, etc. At the same time, oxidation at the benzyl position is also a very important type of reaction, which plays an important role in the modification of natural drugs.

[0004] In recent years, many chemists have made important contributions in the field of the two oxidation reactions mentioned in the present invention, but how to selectively oxidize sulfides to sulfoxides and oxidize benzylic CH bonds under mild conditions is still extremely challenging. Therefore, it is very meaningful to develop some green, economical and efficient reaction methods to achieve such oxidation reactions. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a preparation method for a thioether and benzylic CH bond efficient selective oxidation system. The present invention realizes the selective oxidation of thioether and benzylic CH bond, which has high yield, wide application range of substrates, easy availability of raw materials, good economy, mild reaction conditions and green environmental protection.

[0006] To achieve the purpose of the present invention, the following scheme is adopted:

[0007] A method for preparing a highly efficient selective oxidation system for thioether and benzyl CH bonds, the method for preparing the oxidation product comprising the following steps: ① placing a thioether compound 1 and a photosensitizer in a reaction tube and adding a solvent to dissolve them, ② placing an alkylbenzene and a benzyl ether compound 3 in a reaction tube and dissolving them in the photosensitizer, and placing the reaction tubes ① and ② under ultraviolet light for irradiation to obtain corresponding oxidation products 2 and 4;

[0008]

[0009] After the reaction is completed, most of the solvent is removed by distillation under reduced pressure to obtain a crude product, and the crude product is separated and purified by column chromatography using an eluent to obtain the target product;

[0010] wherein R1 is selected from phenyl, substituted phenyl, benzyl, naphthalene, pyridine, thiophene, thiazole, R2 is selected from C1-3 alkyl, substituted alkyl, phenyl, substituted phenyl, benzyl, R3 is selected from phenyl, substituted phenyl, R4 is selected from alkyl, substituted alkyl; the substituted phenyl is substituted by methyl, halogen, cyano, methoxy, and the substituted alkyl is substituted by halogen;

[0011] The photosensitizer is selected from trichloroacetonitrile, and the solvent is selected from methanol.

[0012] Furthermore, the wavelength range of the purple light is: 395-400 nm LEDs 10W.

[0013] Furthermore, the molar ratio of the sulfide compound to trichloroacetonitrile is 1:0.15; the molar ratio of the alkylbenzene and benzyl ether compounds to trichloroacetonitrile is 1:10.6.

[0014] Furthermore, the eluent is petroleum ether and ethyl acetate.

[0015] Further, in preparing oxidation product 2, the volume ratio of eluent petroleum ether and ethyl acetate is 2:1 to 1:1; in preparing oxidation product 4, the volume ratio of petroleum ether and ethyl acetate is 20:1 to 15:1.

[0016] The technology of the present invention has the following advantages:

[0017] A highly efficient selective oxidation system and application method for thioether and benzylic CH bonds is realized through a visible light-driven free radical reaction. This method is carried out at room temperature through a visible light-driven reaction, and does not use metal photocatalysts, thus avoiding the use of toxic heavy metals. It is a mild, green and environmentally friendly reaction type.

[0018] The preparation process of the invention is simple, efficient and has a high yield. The yield of most target products is more than 90%. The reaction conditions are mild and the target compounds are easy to separate and purify. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] none DETAILED DESCRIPTION

[0020] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention; unless otherwise specified, the raw materials and reagents recorded are commercially available products; all target compounds were identified by NMR ( 1 H, 13C) Spectral data characterization; The yields of the target products in the following examples are all isolated yields.

[0021] The chemical formula of some raw materials used in the examples is as follows

[0022]

[0023] The product chemical formula in the embodiment is as follows

[0024]

[0025] Example 1: A mixture of 1a (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 7 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain product 2a with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.69-7.60 (m, 2H), 7.58-7.46 (m, 3H), 2.73 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 145.74, 131.12, 129.44, 123.55, 44.05.

[0026] Example 2: A mixture of 1b (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 7 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain product 2b with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.64-7.56 (m, 2H), 7.55-7.48 (m, 2H), 2.73 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 144.20, 137.20, 129.65, 124.97, 44.05.

[0027] Example 3: A mixture of 1c (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 12 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain product 2c with a yield of 97%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.71-7.64 (m, 2H), 7.57-7.49 (m, 2H), 2.72 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 144.85, 132.59, 125.47, 125.16, 44.01.

[0028] Example 4: A mixture of 1d (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 21 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain product 2d with a yield of 97%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.64-7.54 (m, 2H), 7.21-7.11 (m, 2H), 2.65 (s, 3H).; 13 C NMR(101 MHz, Chloroform-d) δ 164.54, 162.04, 140.12, 140.09, 124.86, 124.77,115.79, 115.57, 43.16, 43.15.

[0029] Example 5: A mixture of 1e (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 10 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2e with a yield of 97%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows:1 H NMR (400 MHz, Chloroform-d) δ 7.64-7.56 (m, 2H), 7.08-7.00 (m, 2H), 3.86 (s, 3H), 2.71 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 161.96, 136.58, 125.46, 114.85, 55.55,44.02.

[0030] Example 6: A mixture of 1f (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 24 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2f with a yield of 82%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.57-7.51 (m, 2H), 7.33 (d, J = 7.9 Hz, 2H), 2.70 (s, 3H), 2.42 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 142.44, 141.51, 130.04,123.53, 44.00, 21.41.

[0031] Example 7: A mixture of 1g (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2mL) was stirred at room temperature for 3.5 hours under irradiation with 10W purple LEDs (wavelength range: 395-400nm). After the reaction was completed, the reaction mixture was transferred to a 100ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain 2g of the product with a yield of 89%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.15-8.08 (m, 2H), 7.79-7.72 (m, 2H), 2.77 (s, 3H), 2.66 (s, 3H); 13C NMR (101 MHz, Chloroform-d) δ 197.09, 150.91, 139.07, 129.17, 123.76,43.83, 26.84.

[0032] Example 8: A mixture of 1h (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 4 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2h with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.85 (d, J = 8.4 Hz, 2H), 7.78 (d, J = 8.4 Hz, 2H), 2.78 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 151.46, 133.04, 124.33, 117.74, 114.84, 43.84.

[0033] Example 9: A mixture of 1i (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 7 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2i with a yield of 97%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.67 (dt, J = 1.7, 1.1 Hz, 1H), 7.57-7.42 (m, 3H), 2.75 (s, 3H); 13 C NMR(101 MHz, Chloroform-d) δ 147.82, 135.73, 131.23, 130.95, 130.62, 129.18,124.03, 123.65, 121.62, 44.05, 33.85, 3.44, 2.87.

[0034] Example 10: A mixture of 1j (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 16 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2j with a yield of 96%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows 1 H NMR (400 MHz, Chloroform-d) δ 7.52 (td, J = 7.9, 5.2 Hz, 1H), 7.46-7.36 (m, 2H), 7.20 (td,J = 8.3, 2.6 Hz, 1H), 2.75 (s, 3H); 13C NMR (101 MHz, Chloroform-d) δ 164.39,161.89, 148.39, 148.34, 131.14, 131.06, 119.17, 119.14, 118.29, 118.08,110.98, 110.74, 44.04.

[0035] Example 11: A mixture of 1k (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 7 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2k with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.82 (t, J = 1.8 Hz, 1H), 7.63 (ddd, J = 7.9, 2.0, 1.1 Hz, 1H), 7.55 (dt, J = 7.9, 1.3 Hz, 1H), 7.41 (t, J = 7.8 Hz, 1H), 2.75 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 147.97, 134.13, 130.86, 126.47, 123.61,122.09, 44.07.

[0036] Example 12: A mixture of 1l (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 9 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2l with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.42 (t, J = 7.9 Hz, 1H), 7.26 (dd, J = 2.6, 1.6 Hz, 1H), 7.14 (dt, J = 7.7, 1.2 Hz, 1H), 7.02 (ddd, J = 8.2, 2.6, 0.9 Hz, 1H), 3.88(s, 3H), 2.73 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 160.51, 147.17,130.32, 117.44, 115.52, 107.86, 55.61, 44.05.

[0037] Example 13: A mixture of 1m (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 20 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2m with a yield of 97%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.95 (dd, J = 7.8, 1.7 Hz, 1H), 7.64-7.54 (m, 2H), 7.43-7.34(m, 1H), 2.83 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 145.33, 132.94, 132.30, 128.77, 125.71, 118.44, 41.90.

[0038] Example 14: A mixture of 1n (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 12 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2n with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.96 (dd, J = 7.8, 1.7 Hz, 1H), 7.55 (td, J = 7.5, 1.4 Hz, 1H), 7.46 (td, J = 7.6, 1.7 Hz, 1H), 7.40 (dd, J = 7.9, 1.4 Hz, 1H), 2.83 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 143.53, 132.01, 129.79, 129.77, 128.18,125.30, 41.63.

[0039] Example 15: A mixture of 1o (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 6 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2o with a yield of 96%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.65-7.56 (m, 2H), 7.56-7.50 (m, 1H), 7.55-7.45 (m, 2H), 2.91(dq, J = 13.2, 7.4 Hz, 1H), 2.78 (dq, J = 13.3, 7.4 Hz, 1H), 1.20 (t, J = 7.4Hz, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 143.14, 130.96, 129.15, 124.16,50.24, 5.97.

[0040] Example 16: A mixture of 1p (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 14 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2p with a yield of 97%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.69-7.60 (m, 2H), 7.64-7.49 (m, 3H), 3.98 (dt, J = 11.7, 7.5Hz, 1H), 3.66 (ddd, J = 11.9, 6.6, 5.8 Hz, 1H), 3.17 (ddd, J = 7.5, 6.2, 1.3Hz, 2H).; 13C NMR (101 MHz, Chloroform-d) δ 142.77, 131.46, 129.53, 123.91,59.38, 36.70.

[0041] Example 17: A mixture of 1q (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 22 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2q with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.72-7.61 (m, 2H), 7.58-7.45 (m, 3H), 2.27 (tt, J = 7.9, 4.9Hz, 1H), 1.30-1.19 (m, 1H), 1.09-0.98 (m, 1H), 1.02-0.86 (m, 2H).; 13 C NMR (101 MHz, Chloroform-d) δ 144.88, 130.95, 129.18, 124.03, 33.85, 3.44, 2.86.

[0042] Example 18: A mixture of 1r (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 2.5 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2r with a yield of 89%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.51-7.37 (m, 3H), 7.41-7.34 (m, 2H), 7.33-7.13 (m, 3H), 6.98(dt, J = 6.5, 1.7 Hz, 2H), 4.09 (d, J = 12.6 Hz, 1H), 4.00 (d, J = 12.6 Hz,1H); 13 C NMR (101 MHz, Chloroform-d) δ 159.0, 149.3, 147.8, 129.3, 128.9, 125.4, 123.8, 122.9, 117.1, 76.7, 68.9, 33.8, 25.9, 25.5.

[0043] Example 19: A mixture of 1s (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 5 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2s with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.70-7.62 (m, 2H), 7.50-7.43 (m, 2H), 2.82 (hept, J = 6.9 Hz, 1H), 1.24 (d, J = 6.9 Hz, 3H), 1.13 (d, J = 6.8 Hz, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 140.89, 132.12, 126.58, 125.45, 54.59, 15.79, 13.78.

[0044] Example 20: A mixture of 1t (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 24 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2t with a yield of 34%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.43-7.26 (m, 5H), 4.06 (d, J = 12.8 Hz, 1H), 3.93 (d, J =12.8 Hz, 1H), 2.46 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 130.05, 129.67,129.01, 128.47, 60.33, 37.30.

[0045] Example 21: A mixture of 1u (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 15 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2u with a yield of 89%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.42-7.24 (m, 10H), 3.96-3.82 (m, 4H); 13 C NMR (101 MHz, Chloroform-d) δ 130.17, 130.14, 128.99, 128.40, 57.26.

[0046] Example 22: A mixture of 1v (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 17 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2v with a yield of 94%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows:1 H NMR (400 MHz, Chloroform-d) δ 7.65 (dt, J = 7.0, 2.7 Hz, 4H), 7.51-7.39 (m, 6H); 13 C NMR (101 MHz, Chloroform-d) δ 145.58, 131.09, 129.36, 124.80.

[0047] Example 23: A mixture of 1w (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2mL) was stirred at room temperature for 16 hours under irradiation with 10W purple LEDs (wavelength range: 395-400nm). After the reaction was completed, the reaction mixture was transferred to a 100ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2w with a yield of 98%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.93 (dd, J = 7.7, 1.4 Hz, 2H), 7.63 (dd, J = 7.6, 1.2 Hz, 2H), 7.55 (td, J = 7.6, 1.2 Hz, 2H), 7.43 (td, J = 7.6, 1.4 Hz, 2H); 13 C NMR (101 MHz, Chloroform-d) δ 141.39, 129.87, 129.04, 128.45, 128.43, 124.49.

[0048] Example 24: A mixture of 1x (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 22 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2x with a yield of 91%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.66-7.57 (m, 2H), 7.53 (d, J = 8.1 Hz, 2H), 7.49-7.37 (m,3H), 7.25 (d, J = 8.0 Hz, 2H), 2.36 (s, 3H);13 C NMR (101 MHz, Chloroform-d) δ145.78, 142.45, 141.68, 130.91, 130.06, 129.28, 125.00, 124.69, 21.43.

[0049] Example 25: A mixture of 1y (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 10 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2y with a yield of 96%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.02-7.95 (m, 2H), 7.81 (dt, J = 7.7, 0.8 Hz, 2H), 7.60 (td,J = 7.6, 1.2 Hz, 2H), 7.50 (td, J = 7.5, 1.1 Hz, 2H); 13 C NMR (101 MHz, Chloroform-d) δ 145.12, 137.11, 132.59, 129.57, 127.55, 121.94.

[0050] Example 26: A mixture of 1z (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 5 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2z with a yield of 98%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.22 (d, J = 1.8 Hz, 1H), 8.03-7.87 (m, 3H), 7.60 (ddd, J = 7.2, 3.3,1.9 Hz, 3H), 2.80 (s, 3H); 13C NMR (101 MHz, Chloroform-d) δ 142.73, 134.44,132.93, 129.63, 128.54, 128.09, 127.82, 127.39, 124.07, 119.46, 43.82.

[0051] Example 27: A mixture of 1aa (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 20 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2aa with a yield of 99%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.63 (ddd, J = 4.8, 1.7, 0.9 Hz, 1H), 8.04 (dt, J = 7.9, 1.1Hz, 1H), 7.96 (td, J = 7.7, 1.7 Hz, 1H), 7.40 (ddd, J = 7.5, 4.7, 1.3 Hz,1H), 2.86 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 165.92, 149.58, 138.16,124.63, 119.27, 41.31.

[0052] Example 28: A mixture of 1ab (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 4 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2ab with a yield of 89%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.65 (dd, J = 5.0, 1.3 Hz, 1H), 7.49 (dd, J = 3.7, 1.3 Hz, 1H), 7.13 (dd, J = 5.0, 3.6 Hz, 1H), 2.93 (s, 3H); 13C NMR (101 MHz, Chloroform-d) δ 147.33, 130.86, 129.36, 127.44, 44.49.

[0053] Example 29: A mixture of 1ac (0.4 mmol), CCl3CN (0.15 equiv.) and CH3OH (2 mL) was stirred at room temperature for 48 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 2 / 1) to obtain the product 2ac with a yield of 81%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.97 (d, J = 3.1 Hz, 1H), 7.67 (d, J = 3.1 Hz, 1H), 3.02 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 176.65, 144.70, 123.69, 43.39.

[0054] Example 30: A mixture of 3a (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 2 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain product 4a with a yield of 53%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.01-7.93(m, 2H), 7.65-7.53 (m, 1H), 7.47 (m, 2H), 2.62 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 198.13, 137.08, 133.12, 128.57, 128.30, 26.65.

[0055] Example 31: A mixture of 3b (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 5 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain product 4b with a yield of 71%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.84-7.80(m, 2H), 7.64-7.59 (m, 2H), 2.59 (s, 3H). 13 C NMR (101 MHz, Chloroform-d) δ197.06, 135.83, 131.91, 131.33, 129.86, 128.33, 26.55.

[0056] Example 32: A mixture of 3c (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 5 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain product 4c with a yield of 64%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.02 (m,1H), 7.88-7.77 (m, 1H), 7.62 (m, 1H), 7.28 (t, J = 7.9 Hz, 1H), 2.53 (s, 3H); 13 C NMR (101 MHz, Chloroform-d) δ 196.67, 138.81, 135.98, 131.40, 130.21,126.86, 122.97, 26.64.

[0057] Example 33: A mixture of 3d (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 8 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain product 4d with a yield of 51%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1H NMR (400 MHz, Chloroform-d) δ 8.08-8.01(m, 2H), 7.58-7.53 (m, 1H), 7.47-7.41 (m, 2H), 3.92 (s, 3H), 3.39 (s, 1H); 13 CNMR (101 MHz, Chloroform-d) δ 167.15, 132.94, 129.59, 128.41, 128.38, 52.13.

[0058] Example 34: A mixture of 3e (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 10 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain the product 4e with a yield of 61%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 8.17-8.06(m, 4H), 7.66-7.56 (m, 2H), 7.48 (t, J = 7.8 Hz, 4H); 13 C NMR (101 MHz, Chloroform-d) δ 158.85, 137.14, 129.56, 128.65, 128.01, 127.56, 121.01,114.91, 69.95.

[0059] Example 35: A mixture of 3f (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 6 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain the product 4f with a yield of 78%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1H NMR (400 MHz, Chloroform-d) δ 8.10 (dd, J= 7.8, 1.4 Hz, 1H), 7.55 (td, J = 7.6, 1.4 Hz, 1H), 7.40 (td, J = 7.6, 1.2Hz, 1H), 7.28 (d, J = 7.6 Hz, 1H), 4.54 (t, J = 6.0 Hz, 2H), 3.07 (t, J = 6.0Hz, 2H); 13 C NMR (101 MHz, Chloroform-d) δ 165.19, 139.56, 133.71, 130.46, 127.74, 127.25, 125.33, 67.34, 27.86.

[0060] Example 36: A mixture of 3 g (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 10 hours under irradiation with 10 W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain 4 g of the product with a yield of 54%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.70-7.59(m, 1H), 7.17-7.07 (m, 1H), 4.64 (s, 1H); 13 C NMR (101 MHz, Chloroform-d) δ199.95, 174.03, 137.91, 124.10, 122.02, 121.17, 113.69, 74.71.

[0061] Example 37: A mixture of 3h (0.4 mmol) and CCl3CN (0.5 mL) was stirred at room temperature for 10 hours under irradiation with 10W purple LEDs (wavelength range: 395-400 nm). After the reaction was completed, the reaction mixture was transferred to a 100 ml round-bottom flask and the solvent was concentrated in vacuo. The mixture was purified by flash chromatography (petroleum ether / ethyl acetate = 15 / 1) to obtain the product 4h with a yield of 50%. The NMR nuclear magnetic resonance spectrum characterization data of the compound are as follows: 1H NMR (400 MHz, Chloroform-d) δ 8.18 (dd,J = 7.8, 1.9 Hz, 1H), 7.59 (ddd, J = 8.3, 7.4, 1.9 Hz, 1H), 7.14 (td, J =7.6, 1.0 Hz, 1H), 7.07 (dd, J = 8.4, 1.0 Hz, 1H), 4.09 (s, 3H); 13 C NMR (101MHz, Chloroform-d) δ 165.66, 158.12, 135.14, 133.78, 122.18, 117.58, 111.68,56.69.

Claims

1. A method for preparing a highly efficient selective oxidation system for thioethers and benzylic CH bonds, characterized in that: The preparation method of the oxidation product comprises the following steps: ① placing a thioether compound 1 and a photosensitizer in a reaction tube and adding a solvent to dissolve them, ② placing a compound 3 having a benzyl CH bond in a reaction tube and dissolving it in the photosensitizer, and placing the reaction tubes of ① and ② under ultraviolet light to irradiate to obtain corresponding oxidation products 2 and 4; After the reaction is completed, most of the solvent is removed by distillation under reduced pressure to obtain a crude product, and the crude product is separated and purified by column chromatography using an eluent to obtain the target product; wherein R1 is selected from phenyl, substituted phenyl, benzyl, naphthyl, pyridyl, thienyl, thiazolyl, and R2 is selected from C 1-3 Alkyl, substituted alkyl, phenyl, substituted phenyl, benzyl, the substituted phenyl is substituted by methyl, halogen, cyano, methoxy, the substituted alkyl is substituted by halogen; R3 is selected from phenyl, substituted phenyl, R4 is selected from alkyl, the substituted phenyl is substituted by halogen, methoxy; The photosensitizer is selected from trichloroacetonitrile, and the solvent is selected from methanol.

2. The method for preparing a highly efficient selective oxidation system for thioether and benzylic CH bonds according to claim 1, characterized in that: The wavelength range of the purple light: 395-400nm LEDs 10W.

3. The method for preparing a highly efficient selective oxidation system for thioether and benzylic CH bonds according to claim 1, characterized in that: The molar ratio of thioether compound to trichloroacetonitrile is 1:0.15; the molar ratio of compound 3 to trichloroacetonitrile is 1:10.

6.

4. The method for preparing a highly efficient selective oxidation system for thioether and benzylic CH bonds according to claim 1, characterized in that: The eluents are petroleum ether and ethyl acetate.

5. The method for preparing a highly efficient selective oxidation system for thioether and benzylic CH bonds according to claim 4, characterized in that: To prepare oxidation product 2, the volume ratio of eluent petroleum ether and ethyl acetate is 2:1 to 1:1; to prepare oxidation product 4, the volume ratio of eluent petroleum ether and ethyl acetate is 20:1 to 15:1.

Images