A method for preparing an organic sulfide compound using photocatalysis
By using a photocatalytic coupling reaction between disulfide compounds and tetrahydrofuran, the high-temperature and high-risk problems in the synthesis of traditional organosulfur ether compounds have been solved, achieving efficient, green, and low-cost CS bond construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING TECH UNIV
- Filing Date
- 2025-02-14
- Publication Date
- 2026-04-21
AI Technical Summary
Existing methods for synthesizing organosulfur compounds require metal catalysts, oxidants, and high-temperature conditions, and have low economic efficiency and safety, as well as poor substrate universality.
Organic sulfide compounds were prepared by using a photocatalytic system to couple disulfide compounds and tetrahydrofuran under the action of alkali and benzophenone compounds through ultraviolet light irradiation.
It efficiently constructs CS bonds under mild conditions, with environmentally friendly reaction conditions, high yield, and low cost.
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Figure CN120004826B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic synthesis and relates to a method for preparing organosulfur compounds using photocatalysis. Specifically, it relates to a method for synthesizing sulfur compounds by using benzophenone compounds as photocatalysts under alkaline conditions, and by generating sulfur compounds from disulfides and tetrahydrofuran under ultraviolet light catalysis. Background Technology
[0002] With the development of modern science, sulfur-containing compounds have found wide applications in pesticides, pharmaceuticals, chemical dyes, and functional materials. In the biomedical field, the preparation of cyclic analogs of peptides using thioether bonds can improve their bioactivity and resistance to biodegradation by restricting conformational migration. In materials chemistry, sulfur has a profound impact on the physical, electronic, and surface properties of synthesized materials. Vulcanized rubber has revolutionized the rubber industry by significantly improving the physical properties of rubber. Lithium-sulfur batteries possess a higher theoretical specific capacity than lithium-ion batteries, achieving higher energy density and lower cost, making them one of the most promising candidates for next-generation energy storage.
[0003] However, traditional synthesis of sulfur-containing compounds often requires the addition of metal catalysts, additives, oxidants, and high temperatures; some synthetic methods also require pre-functionalization of the substrate, resulting in low atom economy; and some methods have poor substrate universality and a narrow range of applications. Photo-driven organic chemistry reactions are developing rapidly, and significant progress has been made in the field of C(sp3)-H bond functionalization. Currently, methods for constructing C / S bonds through hydrocarbon functionalization require the addition of excess peroxides and high reaction temperatures, resulting in low reaction economy and safety. Summary of the Invention
[0004] The technical problem to be solved by this invention is to provide a new method for preparing organosulfur ether compounds, which addresses the shortcomings of existing technologies. This invention uses a photocatalytic system to achieve the functionalization of carbon-hydrogen bonded substrates under mild conditions, avoiding the use of hazardous peroxides as oxidants, and efficiently constructing compounds containing CS bonds. This method has mild reaction conditions, is environmentally friendly, has a high yield, and is low in cost.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0006] This invention discloses a method for preparing organosulfur ether compounds using photocatalysis. Disulfide compound 1 and tetrahydrofuran undergo a coupling reaction under the action of an alkali and a catalyst, and under ultraviolet light irradiation, to obtain organosulfur ether compound 3.
[0007] The structural formula of the disulfide compound 1 is shown in Formula 1, and the structural formula of the organosulfur ether compound 3 is shown in Formula 3.
[0008]
[0009] in,
[0010] n is an integer selected from 0 to 5;
[0011] R is selected from halogens, substituted or unsubstituted C1-C6 alkyl groups, or substituted or unsubstituted C1-C6 alkoxy groups; wherein the substitution is selected from those substituted by any number of halogens.
[0012] In some embodiments, preferably, n is 0 or 1.
[0013] In some embodiments, preferably, R is selected from fluorine, chlorine, bromine, iodine, substituted or unsubstituted methyl, tert-butyl, or methoxy; wherein the substitution is selected from substitution by any number of halogens.
[0014] In some embodiments, more preferably, R is selected from fluorine, chlorine, bromine, methyl, tert-butyl, trifluoromethyl, or methoxy.
[0015] In some embodiments, the alkali is any one or a combination of several of sodium tert-butoxide, potassium tert-butoxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, and cesium carbonate.
[0016] In some embodiments, preferably, the alkali is cesium hydroxide.
[0017] In some embodiments, the catalyst is a benzophenone compound; the benzophenone compound is any one or a combination of several of benzophenone, 4-chlorobenzophenone, 4-bromobenzophenone, 4-fluorobenzophenone, 4-methylbenzophenone, 4-methoxybenzophenone, and 4,4'-dichlorobenzophenone.
[0018] In some embodiments, preferably, the catalyst is a benzophenone compound; the benzophenone compound is 4-chlorobenzophenone.
[0019] In some embodiments, the molar ratio of the disulfide compound 1 to tetrahydrofuran is 0.2:(20-30).
[0020] In some embodiments, preferably, the molar ratio of the disulfide compound 1 to tetrahydrofuran is 0.2:(22-28), more preferably 0.2:25.
[0021] In some embodiments, the molar ratio of the disulfide compound 1 to the base is 1.0:(2.0 to 2.5).
[0022] In some embodiments, preferably, the molar ratio of the disulfide compound 1 to the base is 1.0:(2.0 to 2.2), and more preferably 1.0:2.0.
[0023] In some embodiments, the molar ratio of the disulfide compound 1 to the catalyst is 1.0:(0.2 to 0.5).
[0024] In some embodiments, preferably, the molar ratio of the disulfide compound 1 to the catalyst is 1.0:(0.3-0.5), more preferably 1.0:0.5.
[0025] In some embodiments, the wavelength of the ultraviolet light is 300–400 nm.
[0026] In some embodiments, the wavelength of the ultraviolet light is 350–400 nm, more preferably 360–375 nm.
[0027] The ultraviolet light originates from an ultraviolet LED lamp with a power of 15-60W, preferably 35-55W, and more preferably 40W.
[0028] In some embodiments, the coupling reaction is carried out at room temperature.
[0029] The coupling reaction described herein takes 12 to 24 hours.
[0030] Beneficial effects:
[0031] This invention provides a novel method for preparing organosulfur compounds. Under light irradiation, a photocatalyst extracts hydrogen atoms from tetrahydrofuran to generate alkyl radicals, which are then converted into carbocations via redox reactions. Simultaneously, disulfide compounds generate sulfur radicals under light irradiation, which produce sulfide anions under alkaline conditions. These sulfide anions and carbocations undergo a coupling reaction to yield sulfide compounds. The method provided by this invention is rationally designed, with mild reaction conditions, is environmentally friendly, and has low cost, achieving a yield of up to 91%. It provides a new method for the synthesis of organosulfur compounds and has promising industrial applications. Attached Figure Description
[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.
[0033] Figure 1 For product 3a 1 H NMR spectrum.
[0034] Figure 2 For product 3a 13 C10 NMR spectrum. Detailed Implementation
[0035] The present invention can be better understood from the following embodiments. However, those skilled in the art will readily understand that the descriptions in the embodiments are for illustrative purposes only and should not, and will not, limit the invention as detailed in the claims.
[0036] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.
[0037] Example 1:
[0038]
[0039] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 79%.
[0040] Product 3a 1 The H NMR spectrum is shown in [reference]. Figure 1 , 13 The C NMR spectrum is shown below. Figure 2 The specific NMR data are as follows: 1 HNMR (400MHz, CDCl3) δ7.54–7.47(m,2H),7.32–7.26(m,2H),7.24–7.19(m,1H),5.64(dd,J=7.2,3.9H z,1H),4.07–3.99(m,1H),3.98–3.92(m,1H),2.42–2.31(m,1H),2.07–1.91(m,2H),1.91–1.83(m,1H); 13 C NMR (100MHz, CDCl3) δ134.6,130.0,127.8,125.8,86.1,66.3,31.6,23.8.
[0041] Example 2:
[0042]
[0043] Under an argon atmosphere, 4,4'-dibromodiphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 WUV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3b, with a yield of 69%.
[0044] The NMR data for compound 3b are as follows: 1 H NMR (400MHz, CDCl3) δ7.43–7.38(m,2H),7.38–7.34(m,2H),5.61(dd,J=7.2,3.8Hz ,1H),4.04–3.93(m,2H),2.37–2.31(m,1H),2.07–1.93(m,2H),1.93–1.84(m,1H); 13 C NMR (100MHz, CDCl3) δ134.96,132.58,131.86,120.93,87.14,67.33,32.62,24.82.
[0045] Example 3:
[0046]
[0047] Under an argon atmosphere, 4,4'-dichlorodiphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 WUV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3c, with a yield of 91%.
[0048] The NMR data for compound 3c are as follows: 1 H NMR (400MHz, CDCl3) δ7.46–7.40(m,2H),7.29–7.23(m,2H),5.60(dd,J=7.2,3.8Hz ,1H),4.05–3.92(m,2H),2.36–2.23(m,1H),2.07–1.94(m,2H),1.93–1.84(m,1H); 13 C NMR (100MHz, CDCl3) δ134.25,132.95,132.42,128.92,87.25,67.31,32.60,25.63.
[0049] Example 4:
[0050]
[0051] Under an argon atmosphere, bis(4-(trifluoromethyl)phenyl) disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3d, with a yield of 83%.
[0052] The NMR data for compound 3d are as follows: 1 H NMR (400MHz, CDCl3) δ7.64–7.48(m,4H),5.75(dd,J=7.3,3.8Hz,1H),4.07–3.93(m,2H),2.49–2.35(m,1H),2.12–1.85(m,3H); 13 CNMR(100MHz, CDCl3)δ141.5,129.5,128.2(q,J=32.7Hz),125.6(q,J=3.7Hz),124.2(q,J=268.0Hz),86.2,67.5,32.6,24.8; 19 F NMR (375MHz, CDCl3) δ -62.5.
[0053] Example 5:
[0054]
[0055] Under an argon atmosphere, bis[4-(tert-butyl)phenyl]disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3e, with a yield of 60%.
[0056] The NMR data for compound 3e are as follows: 1 H NMR (400MHz, CDCl3) δ7.49–7.39(m,2H),7.36–7.28(m,2H),5.73–5.46(m, 1H),4.13–3.83(m,2H),2.41–2.30(m,1H),2.07–1.82(m,3H),1.30(s,9H); 13 C NMR (100MHz, CDCl3) δ150.1,131.9,131.4,125.9,87.4,67.2,34.5,32.6,31.3,24.9.
[0057] Example 6:
[0058]
[0059] Under an argon atmosphere, bis[4-(methoxy)phenyl]disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3f, with a yield of 46%.
[0060] The NMR data for compound 3f are as follows: 1 H NMR (400MHz, CDCl3) δ7.51–7.42(m,2H),6.89–6.80(m,2H),5.52–5.44(m,1H),4.06–3.98(m, 1H),3.97–3.89(m,1H),3.79(s,3H),2.36–2.26(m,1H),2.03–1.91(m,2H),1.90–1.80(m,1H); 13 C NMR (100MHz, CDCl3) δ159.4,134.6,125.5,114.4,88.2,67.2,55.3,32.5,24.9.
[0061] Example 7:
[0062]
[0063] Under an argon atmosphere, bis(4-fluorophenyl) disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, denoted as 3 g of compound, with a yield of 56%.
[0064] The NMR data for 3g of compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.26–7.23(m,3H),6.93–6.88(m,1H),5.68(dd,J=7.2,3.9Hz,1H),4.08–3.93(m,2H),2.44–2.35(m,1H),2.10–1.84(m,3H); 13 C NMR (100MHz, CDCl3) δ162.69 (d, J = 247.8Hz), 138.27 (d, J = 8.0Hz), 129.98 (d, J = 8.5Hz), 125 .92(d,J=3.0Hz),117.20(d,J=22.9Hz),113.53(d,J=21.2Hz),86.78,67.37,32.59,24.81; 19 F NMR (375MHz, CDCl3) δ-112.43.
[0065] Example 8:
[0066]
[0067] Under an argon atmosphere, bis(4-methylphenyl) disulfide (0.20 mmol, 1.0 equiv) and 4-chlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 WUV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, denoted as compound 3h, with a yield of 83%.
[0068] The NMR data for compound 3h are as follows: 1 H NMR (400MHz, CDCl3) δ7.41–7.39(m,2H),7.12–7.10(m,2H),5.57(dd,J=7.2,3.8Hz,1H),4.05–3.9 9(m,1H),3.96–3.91(m,1H),2.37–2.33(m,1H),2.32(s,3H),2.04–1.92(m,2H),1.92–1.81(m,1H); 13 C NMR (101MHz, CDCl3) δ137.07,131.90,131.70,129.62,87.61,67.23,32.60,24.86,21.11.
[0069] The following examples are based on Example 1, and the photocatalysts were screened.
[0070] Example 9:
[0071]
[0072] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and benzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain a crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 22%.
[0073] Example 10:
[0074]
[0075] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-methoxybenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 14%.
[0076] Example 11:
[0077]
[0078] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-methylbenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain a crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 20%.
[0079] Example 12:
[0080]
[0081] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-bromobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 26%.
[0082] Example 13:
[0083]
[0084] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and 4-fluorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 28%.
[0085] Example 14:
[0086]
[0087] Under an argon atmosphere, diphenyl disulfide (0.20 mmol, 1.0 equiv) and 4,4'-dichlorobenzophenone (0.10 mmol, 50.0 mol%) were added to a dry 10 mL Schlenk tube equipped with a magnetic flux. Then, cesium hydroxide aqueous solution (50 wt% aqueous solution, 2.0 equiv cesium hydroxide) and THF (2.0 mL) were added via syringe. The reaction was carried out at room temperature under 40 W UV LED (360-375 nm) illumination for 24 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with EtOAc (3 × 15 mL). The combined organic phases were washed with saturated sodium chloride solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 20:1) to obtain an oily liquid, designated as compound 3a, with a yield of 25%.
[0088] This invention provides a method for preparing organosulfur ether compounds using photocatalysis. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.
Claims
1. A method for preparing organosulfur ether compounds using photocatalysis, characterized in that, Disulfide compound 1 and tetrahydrofuran undergo a coupling reaction under the action of a base and a catalyst, and under ultraviolet light irradiation, to prepare organosulfur ether compound 3. The structural formula of the disulfide compound 1 is shown in Formula 1, and the structural formula of the organosulfur ether compound 3 is shown in Formula 3. ； ； in, n is an integer selected from 0 to 5; R is selected from halogens, substituted or unsubstituted C1-C6 alkyl groups, or substituted or unsubstituted C1-C6 alkoxy groups; wherein the substitution is selected from substitution by any number of halogens; The catalyst is a benzophenone compound; the benzophenone compound is any one or a combination of several of the following: benzophenone, 4-chlorobenzophenone, 4-bromobenzophenone, 4-fluorobenzophenone, 4-methylbenzophenone, 4-methoxybenzophenone, and 4,4'-dichlorobenzophenone.
2. The method according to claim 1, characterized in that, n is 0 or 1.
3. The method according to claim 1, characterized in that, R is selected from fluorine, chlorine, bromine, iodine, substituted or unsubstituted methyl, tert-butyl, or methoxy; wherein the substitution is selected from substitution by any number of halogens.
4. The method according to claim 1, characterized in that, The alkali is any one or a combination of several of sodium tert-butoxide, potassium tert-butoxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, and cesium carbonate.
5. The method according to claim 1, characterized in that, The molar ratio of the disulfide compound 1 to tetrahydrofuran is 0.2:(20~30).
6. The method according to claim 1, characterized in that, The molar ratio of the disulfide compound 1 to the base is 1.0:(2.0~2.5).
7. The method according to claim 1, characterized in that, The molar ratio of the disulfide compound 1 to the catalyst is 1.0:(0.2~0.5).
8. The method according to claim 1, characterized in that, The wavelength of the ultraviolet light is 300~400 nm.
9. The method according to claim 1, characterized in that, The coupling reaction is carried out at room temperature.