Toothed metal complexes and their preparation methods, and preparation methods of α and β-alkenylsilane compounds.
By using bidentate cobalt or tridentate iron complex catalysts, the problems of high catalyst cost and poor performance in traditional alkyne hydrosilylation reactions have been solved, and efficient preparation of α and β alkenylsilane compounds has been achieved. It has the advantages of simple operation, mild conditions, broad substrate versatility and high reaction selectivity.
Patent Information
- Application Number
- CN202411279232.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2044-09-12
AI Technical Summary
Traditional catalysts for the hydrosilylation of alkynes are expensive and have poor catalytic performance, making it difficult to balance catalytic effect and cost, thus limiting the further development of the reaction.
Using bidentate cobalt complexes or tridentate iron complexes as catalysts, α- and β-alkenylsilane compounds are prepared by reacting with alkynes, silanes, and additives in specific solvents. The high catalytic activity and selectivity of cobalt and iron are utilized to achieve highly efficient catalysis.
It realizes the alkyne hydrosilylation reaction with simple operation, mild conditions, broad substrate universality, high reaction selectivity and high catalytic efficiency, and can simultaneously prepare α and β alkenylsilane compounds.
Smart Images
Figure BDA0005041129390000021 
Figure BDA0005041129390000022 
Figure BDA0005041129390000041
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic chemistry technology, specifically relating to toothed metal complexes and their preparation methods, and methods for preparing α and β-alkenylsilane compounds. Background Technology
[0002] Alkynes are an important class of organic compounds with abundant chemical reactivity and diverse structures. They can be converted into organic compounds such as alkenes or cycloalkanes through hydrosilylation reactions, thus expanding the application range of alkynes. Through hydrosilylation reactions of alkynes, a variety of organic compounds with biological activity or industrial applications can be synthesized, such as pharmaceuticals, pesticides, and polymer materials.
[0003] With the advancement of the reaction, significant progress has been made in the hydrosilylation of alkynes. Traditional catalysts, while exhibiting good catalytic performance, are either expensive and difficult to recover, or inexpensive but lack catalytic effectiveness. Therefore, traditional catalysts present a difficult challenge in balancing catalytic performance and cost, limiting the further development of hydrosilylation reactions of alkynes.
[0004] Cobalt and iron, as inexpensive and environmentally friendly transition metals, have been reported in hydrosilylation reactions in recent years. They exhibit good catalytic activity, high catalytic efficiency, and good stability, and the hydrosilylation reactions they catalyze show excellent chemoselectivity and regioselectivity.
[0005] In view of this, the present invention provides a toothed metal complex and its preparation method, as well as a method for preparing α and β-alkenylsilane compounds. This method can simultaneously obtain α and β-alkenylsilane compounds and has the advantages of mild conditions, broad substrate versatility, high reaction selectivity, and high catalytic efficiency. Summary of the Invention
[0006] The purpose of this invention is to provide a toothed metal complex, which is a bidentate cobalt and a tridentate iron pyridine imine complex. It is an effective cobalt and iron catalyst that can be used in the hydrosilylation of alkynes. It has the advantages of broad substrate versatility, high reaction selectivity and high catalytic efficiency.
[0007] To achieve the above objectives, the technical solution adopted is as follows:
[0008] A toothed metal complex, either a bidentate cobalt complex or a tridentate iron complex, has the following general chemical formula:
[0009]
[0010] Where X is a halogen element.
[0011] Furthermore, in the general chemical structural formula of the aforementioned toothed metal complex, R8, R9, and R...10 It is selected from one of the H, Me, iPr, and tBu groups, and X is Cl or Br.
[0012] Another objective of this invention is to provide a simple method for preparing the aforementioned tooth-shaped metal complex.
[0013] To achieve the above objectives, the technical solution adopted is as follows:
[0014] The preparation method of the above-mentioned tooth-shaped metal complex, wherein the chemical reaction formula of the preparation method is as follows:
[0015]
[0016] Another objective of this invention is to provide a method for preparing α and β-alkenylsilane compounds using the aforementioned toothed metal complex. This preparation method is simple to operate, has mild conditions, and can simultaneously yield α and β-alkenylsilane compounds.
[0017] To achieve the above objectives, the technical solution adopted is as follows:
[0018] A method for preparing α- and β-alkenylsilane compounds is as follows:
[0019] Under nitrogen protection, silanes, alkynes, toothed metal complexes, additives and solvents were mixed and reacted at room temperature for 6-24 hours. The mixtures were then concentrated and separated by silica gel column chromatography to obtain α- and β-alkenylsilane compounds, respectively.
[0020] The toothed metal complex is the toothed metal complex described above;
[0021] Furthermore, the molar ratio of the alkyne, silane, toothed metal complex, and additive is 1:1.0-2.0:0.05-0.03:0.01-0.05;
[0022] The volume of the solvent and the molar amount of the alkyne are in the range of 0.5-2 mL: 1 mmol.
[0023] Furthermore, the structural formula of the alkyne is as follows: R1 and R2 are selected from aryl, heteroaryl, alkyl, and hydrogen.
[0024] Furthermore, the silane has the structural formula R3R4R5SiH, wherein R3, R4, and R5 are selected from hydrogen, alkyl, alkoxy, and aryl.
[0025] Furthermore, the solvent is selected from at least one of the following: tetrahydrofuran, diethyl ether, benzene, toluene, ethyl acetate, dichloromethane, acetonitrile, petroleum ether, n-hexane, and N,N dimethylformamide;
[0026] The additive is sodium triethylborohydride or sodium tert-butoxide.
[0027] Furthermore, in the silica gel column chromatography separation process, petroleum ether is used as the eluent.
[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0029] 1. The technical solution of this invention provides an effective cobalt-iron serrated complex that can be used to catalyze the hydrosilylation of alkynes to prepare α- and β-alkenylsilane compounds. Compared to traditional hydrosilylation reactions, it can simultaneously yield α- and β-alkenylsilane compounds.
[0030] 2. In the technical solution of the present invention, an effective cobalt-iron toothed complex is prepared, which can be used to catalyze the hydrosilylation reaction of alkynes. It has the advantages of simple operation, mild conditions, broad substrate universality, high reaction selectivity and high catalytic efficiency, thus having high applicability. Detailed Implementation
[0031] To further illustrate the toothed metal complexes and their preparation methods, as well as the preparation methods of α- and β-alkenylsilane compounds of the present invention, and to achieve the intended objectives of the invention, the following detailed description, in conjunction with preferred embodiments, details the specific implementation methods, structures, features, and effects of the toothed metal complexes and their preparation methods, as well as the preparation methods of α- and β-alkenylsilane compounds proposed according to the present invention. In the following description, different "one embodiment" or "example" does not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.
[0032] The following will provide a more detailed description of the toothed metal complexes and their preparation methods, as well as the preparation methods of α and β-alkenylsilane compounds of the present invention, with reference to specific embodiments:
[0033] The technical solution of this invention is as follows: Under nitrogen protection, silanes, alkynes, synthesized metal complexes (namely, a bidentate cobalt complex and a tridentate iron complex further synthesized from bidentate ligands), additives, and reaction solvents are mixed and reacted at room temperature for 6-24 hours. The reaction is then processed to obtain α- and β-alkenylsilane compounds. This invention utilizes a simple route to obtain bidentate cobalt and tridentate iron pyridine imine complexes, thereby providing an effective method for preparing α- and β-alkenylsilane compounds via cobalt and iron-catalyzed hydrosilylation of alkynes. Compared with existing methods, its advantages include obtaining metal complexes of different tooth types through a single route, which can be used simultaneously to prepare α- and β-alkenylsilane compounds. It has the advantages of simple operation, mild conditions, broad substrate universality, high reaction selectivity, and high catalytic efficiency. In terms of synthesis, it features simple synthesis and high applicability. The technical solution of this invention is as follows:
[0034] A toothed metal complex, either a bidentate cobalt complex or a tridentate iron complex, has the following general chemical formula:
[0035]
[0036] Where X is a halogen element.
[0037] Preferably, in the general chemical structural formula of the toothed metal complex, R8, R9, and R... 10 It is selected from one of the H, Me, iPr, and tBu groups, and X is Cl or Br.
[0038] The preparation method of the above-mentioned tooth-shaped metal complex, wherein the chemical reaction formula of the preparation method is as follows:
[0039]
[0040] In the above technical solution, the structural formula of the pyridine imine ligand is as follows: (i.e., bidentate ligand 1), R6 is aryl, and R7 is Br or pyrazole. The aryl group is represented in aniline form as follows: R8, R9, R 10 It is selected from one of the H, Me, iPr, and tBu groups.
[0041] By further applying metal salts to the synthesized bidentate ligand 1 and tridentate ligand 2, bidentate cobalt complex 3 and tridentate iron complex 4 can be obtained.
[0042] A method for preparing α- and β-alkenylsilane compounds is as follows:
[0043] Under nitrogen protection, silanes, alkynes, toothed metal complexes, additives and solvents were mixed and reacted at room temperature for 6-24 hours. The mixtures were then concentrated and separated by silica gel column chromatography to obtain α- and β-alkenylsilane compounds, respectively.
[0044] The toothed metal complex is the toothed metal complex described above;
[0045] Preferably, the molar ratio of the alkyne, silane, toothed metal complex, and additive is 1:1.0-2.0:0.05-0.03:0.01-0.05;
[0046] The volume of the solvent and the molar amount of the alkyne are in the range of 0.5-2 mL: 1 mmol.
[0047] Preferably, the structural formula of the alkyne is as follows: R1 and R2 are selected from aryl, heteroaryl, alkyl, and hydrogen.
[0048] Preferably, the silane has the structural formula R3R4R5SiH, wherein R3, R4, and R5 are selected from hydrogen, alkyl, alkoxy, and aryl groups. More preferably, the silane is phenylsilane or diphenylsilane.
[0049] Preferably, the solvent is selected from at least one of tetrahydrofuran, diethyl ether, benzene, toluene, ethyl acetate, dichloromethane, acetonitrile, petroleum ether, n-hexane, and N,N dimethylformamide;
[0050] The additive is sodium triethylborohydride or sodium tert-butoxide.
[0051] Preferably, petroleum ether is used as the eluent in the silica gel column chromatography separation process.
[0052] Example 1: Synthesis of tooth-shaped complexes
[0053] The reaction formula is shown below:
[0054]
[0055] In the reaction equation, R8, R9, R 10 It is selected from one of the H, Me, iPr, and tBu groups, and X is Cl or Br.
[0056] The specific steps are as follows:
[0057] (1) Take 5 mmol of 2-bromo-6-acetylpyridine and 7.5 mmol of aniline with different substituents, add 20 ml of methanol as the reaction solvent and 0.1 ml of formic acid as the catalyst, and carry out the amine-aldehyde condensation reaction under reflux conditions for 24 h. Separate the product by chromatographic column, concentrate and purify to obtain bidentate ligand 1.
[0058] (2) Using the obtained bidentate ligand 1 and pyrazole, with CuI and K2CO3 as co-catalysts, DMSO as reaction solvent, and reaction temperature of 120℃, the tridentate ligand 2 can be obtained after 24h of reaction.
[0059] (3) Take 1 mmol of the above-mentioned bidentate ligand 1 or tridentate ligand 2 and 1.1 mmol of the corresponding metal salt (tridentate ligand 2 reacts with FeCl2, and bidentate ligand 1 reacts with CoX2), use THF as the reaction solvent, stir at room temperature for 24 h, filter the precipitate, and you can get complex 3 or 4, that is, the bidentate cobalt complex or the tridentate iron complex.
[0060] Example 2.
[0061] Complex A and complex B were prepared using the method of Example 1, and their structural formulas are shown below:
[0062]
[0063] Specifically:
[0064] During the preparation of complex A: R8, R9, R 10 They are iPr, iPr, and H, respectively, and X is Cl.
[0065] During the preparation of complex B: R8, R9, R 10 They are iPr, iPr, and H, respectively.
[0066] Examples 3-4.
[0067] Complex A, prepared in Example 2, was used for the synthesis of α-alkenylsilane compounds, and complex B was used for the synthesis of β-alkenylsilane compounds.
[0068] Example 3: The specific steps of the Marvin hydrosilylation reaction of alkynes and benzenesilane catalyzed by bidentate cobalt complex A are as follows:
[0069] Under a nitrogen atmosphere, 0.01 mmol (0.004 g) of cobalt complex, 1.0 mmol of alkyne substrate, 1.0 mmol of benzylsilane, 2 mL of THF solution, and 0.05 mmol of triethylborohydride were added sequentially to a reaction tube, and the resulting mixture was stirred at room temperature for 12 h. The reaction solution was then concentrated, and the crude product was subjected to rapid silica gel column chromatography with petroleum ether as the eluent. The eluent containing the target compound was collected, the solvent was evaporated, and the product was dried to obtain the final product.
[0070] The reactants and products are shown in Table 1.
[0071] Table 1
[0072]
[0073] Specifically:
[0074] Product 1: Phenyl(1-phenylvinyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.61 (dt, J = 6.8, 3.4Hz, 2H), 7.43-7.26 (m, 8H), 6.30-6.20 (m, 1H), 5.89-5.80 (m, 1H), 4.86 (s, 2H).
[0075] Product 2: Phenyl(1-(o-tolyl)vinyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.56 (dd, J=7.9, 1.5Hz, 2H), 7.43-7.34 (m, 3H), 7.18-7.11 (m, 3H ),7.02-6.96(m,1H),5.96-5.91(m,1H),5.90-5.81(m,1H),4.72(s,2H),2.26(s,3H).
[0076] Product 3: Phenyl(1-(m-tolyl)vinyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.64-7.58(m,2H),7.44-7.35(m,3H),7.24-7.16(m,3H),7.08(d ,J=6.9Hz,1H),6.24(d,J=2.1Hz,1H),5.82(d,J=2.3Hz,1H),4.85(s,2H),2.35(s,3H).
[0077] Product 4: Phenyl(1-(p-tolyl)vinyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.60 (dt, J=5.4, 2.6Hz, 2H), 7.41-7.36 (m, 3H), 7.30 (d, J=8.1Hz, 2H), 7.1 3(d,J=7.3Hz,2H),6.23(dd,J=8.0,2.3Hz,1H),5.80(t,J=3.3Hz,1H),4.84(s,2H),2.34(s,3H).
[0078] Product 5: (1-(4-methoxyphenyl)vinyl)(phenyl)silane, its NMR data are as follows: 1H NMR (400MHz, CDCl3) δ7.63-7.58(m,2H),7.44-7.30(m,5H),6.89-6.81(m,2H),6.22-6.16(m,1H),5.79-5.73(m,1H),4.83(s,2H),3.80(s,3H).
[0079] Product 6: (1-(4-fluorophenyl)vinyl)(phenyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.61-7.56(m,2H),7.43-7.31(m,5H),7.03-6.96(m,2H),6.21-6.17(m,1H),5.85-5.80(m,1H),4.82(s,2H).
[0080] Product 7: (E)-(1,2-diphenylvinyl)(phenyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.57 (dd, J=7.8, 1.4Hz, 2H), 7.37 (ddd, J=20.7, 9.9, 4.7Hz, 3H), 7.24 (dd, J=5.2, 2.3 Hz,2H),7.21-7.16(m,1H),7.13-7.09(m,3H),7.08-7.04(m,3H),7.02(dd,J=6.8,2.9Hz,2H),4.78(s,2H).
[0081] Example 4: Anti-Markovnikov hydrosilylation of alkynes with benzylsilane catalyzed by tridentate iron complex B
[0082] The specific steps are as follows:
[0083] Under a nitrogen atmosphere, 0.03 mmol (0.012 g) of an iron complex, 1.0 mmol of an alkyne substrate, 2.0 mmol of benzylsilane, 2 mL of THF solution, and 0.01 mmol of sodium tert-butoxide were added sequentially to a reaction tube, and the resulting mixture was stirred at room temperature for 6 h. The reaction solution was then concentrated, and the crude product was subjected to rapid silica gel column chromatography with petroleum ether as the eluent. The eluent containing the target compound was collected, the solvent was evaporated, and the product was dried to obtain the final product.
[0084] The reactants and products are shown in Table 2.
[0085] Table 2
[0086]
[0087] Specifically:
[0088] Product 8: (E)-phenyl(styryl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.65 (dt, J=10.4, 4.1Hz, 2H), 7.48 (dd, J=9.4, 2.3Hz, 2H), 7.43-7 .31(m,6H),7.20(t,J=11.7Hz,1H),6.53(dt,J=19.0,3.3Hz,1H),4.72(d,J=3.3Hz,2H).
[0089] Product 9: (E)-(3-methylstyryl)(phenyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.75-7.71(m,2H),7.55-7.45(m,4H),7.39-7.32(m,3H),7.21(d,J =5.6Hz,1H),6.59(dt,J=19.0,3.3Hz,1H),4.80(d,J=3.2Hz,2H),2.45(d,J=6.2Hz,3H).
[0090] Product 10: (E)-(2-([1,1'-biphenyl]-4-yl)vinyl)(phenyl)silane, its NMR data are as follows: 1 HNMR(400MHz, CDCl3)δ7.65(dd,J=7.6,1.7Hz,2H),7.62-7.58(m,4H),7.54(d,J=8.4Hz,2H),7 .47-7.35(m,6H),7.19(t,J=12.0Hz,1H),6.56(dt,J=19.0,3.3Hz,1H),4.73(d,J=3.2Hz,2H).
[0091] Product 11: (E)-(4-fluorostyryl)(phenyl)silane, its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.63 (dt, J=7.6, 3.7Hz, 2H), 7.43 (dt, J=9.9, 5.9Hz, 5H), 7.17- 7.12(m,1H),7.07-6.99(m,2H),6.43(dt,J=19.0,3.2Hz,1H),4.71(d,J=3.2Hz,2H).
[0092] Product 12: (E)-phenyl(2-(thiophen-3-yl)vinyl)silane, its NMR data are as follows: 1H NMR (400MHz, CDCl3) δ7.61 (dt, J=4.5, 2.2Hz, 2H), 7.41-7.36 (m, 3H), 7.26 (ddd, J=7.3, 3.9, 1.7Hz, 3H), 7.13 (d, J=18.9Hz, 1H), 6.27 (ddd, J=8.8, 6.5, 3.2Hz, 1H), 4.67 (d, J=3.2Hz, 2H).
[0093] As can be seen from Examples 3-4, the toothed metal complexes prepared by the present invention have the advantages of high reaction selectivity and high catalytic efficiency when used to catalyze the hydrosilylation reaction of alkynes.
[0094] Example 5.
[0095] The specific steps are as follows:
[0096] (1) A bidentate cobalt complex was prepared using the method described in Example 1, wherein R8, R9, and R 10 They are Me, H, and Me respectively, and X is Br.
[0097] (2) Under a nitrogen atmosphere, 0.005 mmol (0.002 g) of the bidentate cobalt complex prepared in step (1), 1.0 mmol of the alkyne substrate (CH3C≡CH), 1.5 mmol of the silane (CH3O-SiH2-C6H5), 1.5 mL of diethyl ether solution, and 0.01 mmol of triethylborohydride were added sequentially to the reaction tube, and the resulting mixture was stirred at room temperature for 24 h. The reaction solution was then concentrated, and the crude product was subjected to rapid silica gel column chromatography. Petroleum ether was used as the eluent for silica gel column chromatography. The eluent containing the target compound was collected, the solvent was evaporated, and the product was dried to obtain the final product. NMR analysis confirmed the presence of alkenylsilane compounds. The product yields were all greater than 75%.
[0098] Example 6.
[0099] The specific steps are as follows:
[0100] (1) A bidentate cobalt complex was prepared using the method described in Example 1, wherein R8, R9, and R 10 H, tBu, and tBu are respectively, and X is Cl.
[0101] (2) Under a nitrogen atmosphere, 0.01 mmol (0.004 g) of the bidentate cobalt complex prepared in step (1), 1.0 mmol of the alkyne substrate (CH3C≡CCH3), 2.0 mmol of diphenylsilane (C6H5-SiH2-C6H5), 0.5 mL of benzene solution, 1.0 mL of toluene solution, and 0.02 mmol of triethylborohydride were added sequentially to the reaction tube, and the resulting mixture was stirred at room temperature for 18 h. The reaction solution was then concentrated, and the crude product was subjected to rapid silica gel column chromatography. Petroleum ether was used as the eluent for silica gel column chromatography. The eluent containing the target compound was collected, the solvent was evaporated, and the product was dried to obtain the final product. NMR analysis confirmed the presence of alkenylsilane compounds. The product yields were all greater than 72%.
[0102] Example 7.
[0103] The specific steps are as follows:
[0104] (1) Tridentate iron complexes were prepared using the method described in Example 1, wherein R8, R9, and R 10 They are Me, H, and Me, respectively.
[0105] (2) Under a nitrogen atmosphere, 0.005 mmol (0.002 g) of the tridentate iron complex prepared in step (1), 1.0 mmol of the alkyne substrate (C6H5C≡CH), 1.0 mmol of the silane (CH3-SiH2-C6H5), 0.5 mL of N,N dimethylformamide solution, and 0.01 mmol of sodium tert-butoxide were added sequentially to the reaction tube, and the resulting mixture was stirred at room temperature for 18 h. The reaction solution was then concentrated, and the crude product was subjected to rapid silica gel column chromatography. Petroleum ether was used as the eluent for silica gel column chromatography. The eluent containing the target compound was collected, the solvent was evaporated, and the product was dried to obtain the final product. NMR analysis confirmed the presence of alkenylsilane compounds. The product yields were all greater than 70%.
[0106] Example 8.
[0107] The operation steps of Example 8 are the same as those of Product 1 in Example 3, except that ethyl acetate, dichloromethane, acetonitrile, petroleum ether, and n-hexane are used as solvents respectively.
[0108] The final products were analyzed by NMR, yielding alkenylsilane compounds. The yields of all products were greater than 80%.
[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. A toothed metal complex, characterized in that, The aforementioned toothed metal complex is a tridentate iron complex, and its general chemical formula is: In the general chemical structural formula of the toothed metal complex, R8, R9, and R 10 It is selected from one of the H, Me, iPr, and tBu groups.
2. The method for preparing the tooth-shaped metal complex according to claim 1, characterized in that, The chemical reaction formula for the preparation method is as follows:
3. A method for preparing α- and β-alkenylsilane compounds, characterized in that, The preparation method is as follows: Under nitrogen protection, silanes, alkynes, toothed metal complexes, additives and solvents were mixed and reacted at room temperature for 6-24 hours. The mixtures were then concentrated and separated by silica gel column chromatography to obtain α- and β-alkenylsilane compounds, respectively. The toothed metal complex is the toothed metal complex according to claim 1; The structural formula of the alkyne is as follows: R1 and R2 are selected from one of aryl, heteroaryl, alkyl, and hydrogen; The silane has the structural formula R3R4R5SiH, wherein R3, R4, and R5 are selected from hydrogen, alkyl, alkoxy, and aryl groups. The additive is sodium triethylborohydride or sodium tert-butoxide.
4. The preparation method according to claim 3, characterized in that, The molar ratio of the alkyne, silane, toothed metal complex, and additive is 1:1.0-2.0:0.05-0.03:0.01-0.05; The ratio of the volume of the solvent to the molar amount of the alkyne is 0.5-2 mL: 1 mmol.
5. The preparation method according to claim 3, characterized in that, The solvent is selected from at least one of the following: tetrahydrofuran, diethyl ether, benzene, toluene, ethyl acetate, dichloromethane, acetonitrile, petroleum ether, n-hexane, and N,N dimethylformamide.
6. The preparation method according to claim 3, characterized in that, In the silica gel column chromatography process, petroleum ether is used as the eluent.