Preparation method of polyimide and application of polyimide in drug molecule trifluoromethylation photoreaction

Abstract

The invention relates to a preparation method of polyimide and application of the polyimide in photoreaction of drug molecule trifluoromethylation, and mainly provides a novel method for orthogonal condensation between aryl dianhydride and polyaniline, so that a series of electron acceptor donor type polyimide materials are rapidly constructed. The material can be used as a heterogeneous photocatalyst for catalyzing visible light induced aromatic hydrocarbon trifluoromethylation reaction. The method has the advantages and effects of mild conditions, no transition metal catalysis, repeated use of the catalyst, greenness, sustainability and the like. More importantly, the method can be applied to modification after trifluoromethylation of a plurality of drug molecules, and shows a huge application prospect in the field of pharmaceutical chemicals.

Description

Technical Field

[0001] The invention belongs to the field of material chemistry and relates to organic synthesis technology, in particular to a method for preparing a polyimide homogeneous photocatalyst and its application in trifluoromethylation synthesis of drug molecules. Background Art

[0002] As a shining pearl in the current field of green chemistry, the synthesis reaction induced by visible light shows great potential for directly converting light energy into chemical energy. However, the practical challenge is that most organic compounds do not have the ability to effectively absorb in the visible light region, making it difficult to directly utilize this natural resource. To overcome this obstacle, the academic community introduced photocatalysts as a medium to capture visible light energy, realize the transition from the ground state to the excited state, and use this as a driving force to promote subsequent chemical reactions. According to the existence form in the reaction system, photocatalysts can be divided into two categories: homogeneous and heterogeneous. In the homogeneous system, photocatalysts are further divided into two camps: transition metal complexes and organic dyes. Although transition metal complexes are known for their excellent optical properties, their application in the fields of medicine and chemical industry is severely restricted due to heavy metal residues, potential toxic threats and high costs. On the other hand, although organic dyes are cost-effective, their structural instability leads to easy photobleaching during the catalytic process, affecting the durability of the catalytic effect. Therefore, in the pursuit of a greener, more efficient and economical synthesis route, how to balance the optical activity, cost-effectiveness and environmental friendliness of photocatalysts has become a key issue that researchers need to solve urgently.

[0003] Polyimide, as a rising star in the field of donor-acceptor polymers, has greatly enhanced the efficiency of charge separation and the stability of electron-hole pairs with its iconic covalent imide bond structure and unique donor-acceptor alternating arrangement design, and has gradually become a multifunctional heterogeneous photocatalytic platform with highly flexible and controllable structure. In particular, the π-π stacking mechanism unique to aromatic polyimides can significantly accelerate the flow of charges and the electronic polarization process within the material, opening up more efficient charge transfer channels, thereby greatly improving the activity and efficiency of the catalyst. In addition, in the excited state of polyimide, the periodically arranged long-lived carbonyl radical anions in its structure not only greatly enhance the stability of the excitons, but also effectively inhibit the exciton recombination phenomenon, further optimizing the overall performance of the heterogeneous photocatalyst.

[0004] On the other hand, the trifluoromethyl group, a widely existing core pharmacophore, profoundly affects many key physical and biological properties of the parent molecule, including but not limited to permeability, oil-water partition ratio, biocompatibility and metabolic stability, and its regulatory role cannot be ignored. In recent years, given the core position of trifluoromethyl aromatic compounds in popular drugs and high-efficiency pesticides, the study of trifluoromethylation of aromatic compounds directly through photochemical reactions has become a research hotspot and frontier exploration in academia. Early research progress mainly relied on the use of high-cost ruthenium-based complexes or stoichiometric acetone as homogeneous photocatalysts to promote the smooth progress of the reaction. However, the problem of catalyst residues emerged and became a bottleneck restricting its widespread application. Based on Rh-modified TiO2 nanoparticles and innovative mesoporous graphitic carbon nitride heterogeneous photocatalyst systems, C Ar The oxidative trifluoromethylation of –H bonds has opened up a new path for the development of the field. Nevertheless, an in-depth analysis from the perspective of the reaction mechanism found that the current heterogeneous catalytic system has not yet gotten rid of its dependence on external oxidants. This situation not only shows the limitations of current technology, but also further highlights the urgent need and significance of developing new trifluoromethylation photocatalysts that are more efficient, environmentally friendly, and have clear mechanisms. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a new method for orthogonal condensation between aromatic dianhydrides and polyanilines, thereby quickly constructing a series of electron acceptor donor polyimide materials. At the same time, the application of the method in catalyzing visible light-induced trifluoromethylation of aromatic hydrocarbons has important application significance in the field of pharmaceuticals and chemical industry.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A method for preparing polyimide, the method comprising: fully mixing aromatic dianhydride, i.e., electron acceptor, and polyarylamine, i.e., electron donor, to obtain a polymer; transferring the polymer to a tube furnace; heating the temperature to 350°C at 5°C / min in a nitrogen atmosphere; maintaining the temperature for 8 hours; then, performing continuous Soxhlet extraction on the crude product and vacuum drying to obtain a target product polyimide, wherein the target product polyimide structural formula comprises:

[0008]

[0009] Among them, PI stands for polyperylene imide, NI stands for polynaphthalimide, and BI stands for polyphenylimide.

[0010] Furthermore, an application of the above-mentioned synthetic product polyimide is provided, which is used to catalyze the visible light-induced trifluoromethylation reaction of aromatic hydrocarbons, and the reaction equation is as follows:

[0011]

[0012] Furthermore, the reaction conditions include: using aromatic hydrocarbons, benzene rings or heterocycles, and trifluoromethylsulfenyl chloride as starting materials, polyimide as a photocatalyst, and dipotassium hydrogen phosphate as a base at room temperature, in a nitrogen atmosphere, and irradiating with 430nm LED blue light. After the reaction is complete, separation and purification are performed to obtain a series of trifluoromethylation products of drug molecules, among which polyimide can be separated by filtration or centrifugation and can be reused after drying.

[0013] The advantages and positive effects of the present invention are:

[0014] 1. The method of the present invention mainly provides a new method for orthogonal condensation between aromatic dianhydrides and polyanilines, and quickly constructs a series of electron acceptor donor polyimide materials. The method has many advantages such as mild conditions, no transition metal catalysis, repeated use of catalysts, and green sustainability. The polyimide material prepared by the method of the present invention can be used as a heterogeneous photocatalyst to catalyze the visible light-induced trifluoromethylation reaction of aromatics. More importantly, the method can be applied to the post-trifluoromethylation modification of many drug molecules, showing its huge application prospects in the field of pharmaceutical chemicals.

[0015] 2. The present invention innovatively introduces polyimide as a heterogeneous photocatalyst, overcoming the limitations of traditional homogeneous photocatalysts such as high cost, heavy metal residue risk, structural instability, and difficulty in recycling and reuse. At the same time, the polyimide photocatalyst exhibits excellent catalytic efficiency, realizes the trifluoromethylation structural post-modification of aromatic drug molecules, and has many advantages such as mild conditions, wide substrate application range, and green sustainability, opening up new application technologies for the design and synthesis of fluorine-containing drug molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A synthesis diagram of a preparation method of a polyimide of the present invention;

[0017] Figure 2 This is a photoreaction process diagram of direct trifluoromethylation of aromatic hydrocarbons catalyzed by a polyimide according to the present invention. DETAILED DESCRIPTION

[0018] A method for preparing a polyimide designed by the present invention comprises the following steps: Figure 1Specifically, A represents an electron acceptor, namely aromatic dianhydride; D represents an electron donor, namely polyarylamine, and 12 electron donor-acceptor type polyimides are successfully constructed through nucleophilic condensation reaction of the two. The specific steps of the method include: in a nitrogen atmosphere, orthogonally mixing four electron donor components, namely 1,3,5-tris(4-aminophenyl)benzene (D1), (ethylene-1,1,2,2-tetrayl)tetraphenylamine (D2), (1,3,5-triazine-2,4,6-triyl)triphenylamine (D3), tris(4-aminophenyl)amine (D4) and three electron acceptor components, namely 3,4,9,10-floretetaracarboxylic dianhydride (A1), 1,4,5,8-naphthalenetetracarboxylic dianhydride (A2), 1,2,4,5-benzenetetracarboxylic anhydride (A3), transferring the polymer into a tube furnace, heating to 350°C at 5°C / min in a nitrogen atmosphere, and calcining at this temperature for 8 hours. The crude product is continuously Soxhlet extracted and vacuum dried to obtain the target polyimide. According to the specific electron acceptor unit structure, the above polyimides can be divided into three series, namely, perylene imide (PI-1, PI-2, PI-3, PI-4), naphthyl imide (NI-1, NI-2, NI-3, NI-4) and benzimide (BI-1, BI-2, BI-3, BI-4).

[0019] At the same time, the present invention provides a polyimide-catalyzed direct trifluoromethylation photoreaction of aromatic hydrocarbons, the reaction equation is as follows: Figure 2 As shown. Specifically, the trifluoromethylation photoreaction, the aromatic drug substrates include: pirfenidone, caffeine, pentoxifylline, doxaphylline, tangeretin, griseofulvin, paroxetine, gemfibrozil ester, naproxen ester. The trifluoromethylation photoreaction, its characteristic reaction conditions include: in a 10mL Schlenk tube, 0.2mmol of aromatic compound, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst are stirred evenly in 2.0mL acetonitrile. Subsequently, under nitrogen atmosphere and room temperature, the reaction system is irradiated with a 10W blue LED lamp. When the aromatic substrate is completely consumed, the reaction mixture is concentrated under vacuum conditions, and the resulting residue is purified by silica gel chromatography, using petroleum ether / ethyl acetate as an eluent to finally obtain the target product. The photocatalyst can also be separated from the reaction system by filtration or centrifugation and reused.

[0020] Example 1

[0021] In a 10mL Schlenk tube, 0.2mmol of diclazuril, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When diclazuril was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0022]

[0023] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=5:1, v / v) afforded the title compound as a white solid (44.8mg, 46% yield), mp 77.4–79.0℃; 1 H NMR(400MHz,Chloroform-d)δ7.72(s,2H),7.48–7.33(m,2H),7.34–7.28(m,2H),6.20(s,1H),3.47(s,3H). 13 C{ 1 H}NMR(101MHz,Chloroform-d)δ151.4,147.3,140.3,136.2,134.5,131.4,130.5,1 29.3,128.2,127.0(q,J=32.8Hz),125.3,118.9(q,J=274.9Hz),116.0,37.0,28.1. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-67.83.HRMS(ESI-TOF)m / z:[M+NH4] + Calculate for C 19 H 14 Cl3F3N5O2,488.9894; found:488.9888.

[0024] Example 2

[0025] In a 10mL Schlenk tube, 0.2mmol of pirfenidone, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, a 10W blue LED lamp was used to irradiate the reaction system under nitrogen atmosphere and room temperature. When pirfenidone was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to obtain the target product.

[0026]

[0027] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=5:1, v / v) afforded the title compound as a white solid (20.0mg, 39% yield), 1 H NMR (400MHz, Chloroform-d) δ7.69 (d, J = 2.6 Hz, 1H), 7.57–7.40 (m, 3H), 7.39–7.31 (m, 3H), 2.17 (d, J = 1.0 Hz, 3H). 13 C{ 1 H} NMR (101MHz, Chloroform-d) δ 157.5, 141.7 (q, J = 5.0Hz), 140.0, 139.4, 129.4, 128.9, 126.5, 122.6 (q, J = 272.0Hz), 121.0 (q, J = 30.7Hz), 113.1, 17.0. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-65.88.

[0028] Example 3

[0029] In a 10mL Schlenk tube, 0.2mmol of caffeine, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When the caffeine was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0030]

[0031] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=5:1, v / v) afforded the title compound as a white solid (43.5mg, 83% yield); 1H NMR(400MHz,Chloroform-d)δ4.14(s,3H),3.57(s,3H),3.40(s,3H).13C{1H}NMR(101MHz,Chloroform-d)δ155.3,151.1, 146.3,138.7(q,J=40.0Hz),118.0(q,J=271.3Hz),109.4,33.0,29.7,28.0.19F{1H}NMR(376MHz,Chloroform-d)δ-62.42.

[0032] Example 4

[0033] In a 10mL Schlenk tube, 0.2mmol of pentoxifylline, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When pentoxifylline was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to obtain the target product.

[0034]

[0035] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=5:1, v / v) afforded the title compound as a white solid (52.6 mg, 76% yield); 1 H NMR (400MHz, Chloroform-d) δ4.12(d,J=1.3Hz,3H),4.03–3.85(m,2H),3.54(s,3H),2.47(t,J=6.9Hz,2H),2.12(s,3H),1.74–1.46(m,4H). 13 C{ 1H}NMR(101MHz,Chloroform-d)δ208.6,155.3,151.1,146.6,138.9(q,J=39.8Hz),118.2(q,J=271.2Hz),109.7,43.1,41.1,33.2,30.0,29.8,27.3,20.9. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-62.42.

[0036] Example 5

[0037] In a 10mL Schlenk tube, 0.2mmol of doxaphylline, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When doxaphylline was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to obtain the target product.

[0038]

[0039] In a 10mL Schlenk tube, 0.2mmol of aromatic compound, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When the aromatic substrate was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0040] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=5:1, v / v) afforded the title compound as a yellow solid (23.4mg, 35% yield); 1 H NMR (400MHz, Chloroform-d) δ5.34(t,J=4.4Hz,1H),4.68(d,J=4.4Hz,2H),3.97–3.88(m,4H),3.60(s,3H),3.42(s,3H). 13 C{ 1H}NMR(101MHz,Chloroform-d)δ155.3,151.3,146.7,139.2(q,J=39.8Hz),118.2(q,J=271.6Hz),109.5,100.9,65.3,48.7,29.9,28.3. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-60.79.

[0041] Example 6

[0042] In a 10mL Schlenk tube, 0.2mmol of tangeretin, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When tangeretin was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0043]

[0044] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=10:1, v / v) afforded the title compound as a white solid (49.3 mg, 56% yield); 1 H NMR (400MHz, Chloroform-d) δ7.60(d,J=8.8Hz,2H),7.03(d,J=8.8Hz,2H),4.10(s,3H),3.99(s,3H),3.96(s,3H),3.93(s,3H),3.91(s,3H). 13 C{ 1 H}NMR(101MHz,Chloroform-d)δ173.6,164.9,162.3,152.1,148.5,146.8,144.9,137.7,130.8 ,124.3,122.9(q,J=274.7Hz),114.2,113.9,112.3(q,J=29.0Hz),62.3,62.1,61.8,61.7,55.5. 19 F{ 1H}NMR(376MHz,Chloroform-d)δ-56.05.

[0045] Example 7

[0046] In a 10mL Schlenk tube, 0.2mmol of griseofulvin, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When griseofulvin was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0047]

[0048] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=10:1, v / v) afforded the title compound as a yellow liquid (45.9mg, 57% yield); 1 H NMR(400MHz,Chloroform-d)δ6.17(s,1H),4.04(s,3H),3.98(s,3H),3.84(s,3H),3.10(dd, J=16.8,13.9Hz,1H),2.87–2.78(m,1H),2.50(dd,J=16.8,4.9Hz,1H),0.94(d,J=6.7Hz,3H). 13 C{ 1 H}NMR(101MHz,Chloroform-d)δ191.9,190.8,173.0,169.0,165.1,158.0,121.6(q,J=275.9Hz) ,118.0(q,J=28.1Hz),104.9,97.4,92.1,90.1,64.4(q,J=2.7Hz),57.2,56.5,40.0,35.9,14.1. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-58.45.HRMS(ESI-TOF)m / z:[M+Na] + Calculate for C 18 H 16ClF3NaO6,433.0480; found:433.0485.

[0049] Example 8

[0050] In a 10mL Schlenk tube, 0.2mmol of paroxetine, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred evenly in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When paroxetine was completely consumed, the reaction mixture was concentrated under vacuum conditions, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0051]

[0052] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=10:1, v / v) afforded the title compound as a colorless liquid (34.8mg, 35% yield); 1 H NMR(400MHz,Chloroform-d)δ7.16–7.10(m,2H),6.99(s,1H),6.96(d,J=8.6Hz,2H),6.26(s,1H),5.94(s,2H),δ4.46–4.20(m,2H),3.67(dd ,J=9.1,2.5Hz,1H),3.51(d,J=8.3Hz,1H),2.84(d,J=46.5Hz,3H),2.03(d,J=19.6Hz,1H),1.86–1.79(m,1H),1.73–1.65(m,1H)1.50(s,9H). 13 C{ 1 H}NMR(101MHz,Chloroform-d)δ162.9,160.4,154.9,153.0,151.1,140.7,139.0(d,J=3.3Hz),128.8(d,J=7.8Hz),123.8 (q,J=271.6Hz),115.7,115.5,110.6(q,J=31.5Hz),106.7(q,J=5.7Hz),102.0,95.5,79.7,68.9,43.8,42.0,33.8,28.5. 19 F{ 1H}NMR(376MHz,Chloroform-d)δ-60.56,-116.05.HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 25 H 27 F4NO5,498.1898; found:498.1899.

[0053] Example 9

[0054] In a 10mL Schlenk tube, 0.2mmol of gemfibrozil ester, 0.4mmol of trifluoromethanesulfonyl chloride and 2mg of PI-2 photocatalyst were stirred in 2.0mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10W blue LED lamp under nitrogen atmosphere and room temperature. When gemfibrozil ester was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0055]

[0056] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=10:1, v / v) afforded the title compound as a colorless solid (41.2mg, 62% yield); 1 H NMR(400MHz,Chloroform-d)δ7.34(s,1H),6.63(s,1H),3.95(t,J=5.7Hz,2H),3 .67(s,3H),2.42(d,J=2.0Hz,3H),2.19(s,3H),1.98–1.58(m,4H),1.22(s,6H). 13 C{ 1 H}NMR(101MHz,Chloroform-d)δ178.2,159.0,135.7,128.0(q,J=5.4Hz),125.0(q,J=272 .6Hz), 123.9, 120.4 (d, J = 29.8Hz), 113.8, 68.1, 51.8, 42.1, 37.0, 25.2, 25.0, 19.4, 15.6. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-59.91.

[0057] Example 10

[0058] In a 10 mL Schlenk tube, 0.2 mmol of naproxen ester, 0.4 mmol of trifluoromethanesulfonyl chloride and 2 mg of PI-2 photocatalyst were stirred in 2.0 mL of acetonitrile. Subsequently, the reaction system was irradiated with a 10 W blue LED lamp under nitrogen atmosphere and room temperature. When the naproxen ester was completely consumed, the reaction mixture was concentrated under vacuum, and the residue was purified by silica gel chromatography using petroleum ether / ethyl acetate as eluent to finally obtain the target product.

[0059]

[0060] Purification by column chromatography on silica gel (petroleum ether / ethyl acetate=10:1, v / v) afforded the title compound as a colorless liquid (20.0mg, 32% yield); 1 H NMR(400MHz,Chloroform-d)δ8.13(d,J=10.7Hz,1H),7.89(d,J=9.2Hz,1H),7.65(d,J=1.9Hz,1H),7.46(dd,J= 9.1, 2.1Hz, 1H), 7.25 (d, J = 9.2Hz, 1H), 3.93 (s, 3H), 3.81 (q, J = 7.1Hz, 1H), 3.62 (s, 3H), 1.53 (d, J = 7.2Hz, 3H). 13 C{ 1 H}NMR(101MHz,Chloroform-d)δ174.8,156.9,136.3,134.2,130.2,129.1,128.1 ,126.8,124.5(q,J=5.2Hz),122.6(q,J=276.3Hz),114.4,57.2,52.2,45.0,18.4. 19 F{ 1 H}NMR(376MHz,Chloroform-d)δ-52.63.HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 16 H 16 F3O3,313.1046; found:313.1043.

[0061] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing a polyimide, characterized in that: The method comprises: fully mixing aromatic dianhydride, i.e., electron acceptor, and polyarylamine, i.e., electron donor, to obtain a polymer; transferring the polymer into a tube furnace; heating the temperature to 350° C. at 5° C. / min in a nitrogen atmosphere; maintaining the temperature for 8 hours; then, performing continuous Soxhlet extraction on the crude product and vacuum drying to obtain a target product, polyimide; the target product polyimide structural formula comprises: Among them, PI stands for polyperylene imide, NI stands for polynaphthalimide, and BI stands for polyphenylimide.

2. An application of the polyimide according to claim 1, characterized in that: It is applied to catalyze the visible light-induced trifluoromethylation reaction of aromatic hydrocarbons, and the reaction equation is as follows:

3. The use of a polyimide according to claim 2, characterized in that: The reaction conditions include: using aromatic hydrocarbons, benzene rings or heterocycles, and trifluoromethylsulfenyl chloride as starting materials, polyimide as a photocatalyst, and dipotassium hydrogen phosphate as a base at room temperature, in a nitrogen atmosphere, and irradiating with 430nm LED blue light. After the reaction is complete, separation and purification are performed to obtain a series of trifluoromethylation products of drug molecules, among which polyimide can be separated by filtration or centrifugation and can be reused after drying.

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