Synthesis method and application of a novel photocatalyst 3-benzyl-4-(tetrahydroisoquinolinyl) maleimide derivative

Abstract

The present application relates to the field of C-N coupling synthetic methodology and the field of organic photocatalysis, and in particular to a novel photocatalyst, 3-benzyl-4-(tetrahydroisoquinolinyl) maleimide derivative synthesis method and application. The present application realizes the one-step synthesis of a novel photocatalyst, 3-benzyl-4-(tetrahydroisoquinolinyl) maleimide derivative, from tetrahydroisoquinoline and methylene succinimide compound under the catalysis of elemental iodine in an air atmosphere. The technical scheme has the advantages of cheap and readily available raw materials, no need to use transition metal catalysis, simple operation, etc. The construction of C-N bond can be realized in one step to synthesize the target product by using cheap elemental iodine catalysis. The series of derivatives obtained by the present application have suitable redox potential, and can be used as photocatalysts to catalyze multiple reactions; the catalytic efficiency is high, and only 0.5-1% loading is needed to catalyze the reaction.

Description

Technical Field

[0001] This invention relates to the fields of CN coupling synthesis methodology and organic photocatalysis, specifically to a method for synthesizing and applying a novel photocatalyst—a 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative. Background Technology

[0002] Visible light-catalyzed organic synthesis reactions have developed rapidly in the past 20 years, leading to the development of a series of organic photocatalysts, such as iridium and ruthenium-based catalysts, 4CzIPN, eosin Y, acridine salts, nitrogen carbonides, and carbon quantum dots. While these catalysts are widely used in organic synthesis, the development of newer, cheaper, more readily available, easier-to-store, and more tunable photocatalysts remains crucial as organic synthesis methodologies evolve.

[0003] Currently, there are many photocatalysts on the market, but they all have some problems in terms of synthesis and application. For example, transition metal iridium and ruthenium catalysts have problems such as metal residue; organic catalysts have problems such as difficult synthesis, high cost, poor universality for reactions, difficulty in storage, and difficulty in controlling catalyst molecules. Therefore, based on the above-mentioned problems, the technical problem to be solved by this invention is to develop novel tunable photocatalysts that can be efficiently synthesized using simple raw materials under mild reaction conditions. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings and deficiencies of existing technologies by providing a novel method for preparing photocatalysts. The synthesis method utilizes inexpensive elemental iodine catalysis, eliminates the need for transition metal catalysis, and offers advantages such as a simple reaction system and convenient experimental operation. Furthermore, the derivatives in this series all possess suitable redox potentials, enabling them to catalyze a wide range of reactions. This invention addresses the problems of photocatalyst synthesis and application from both technical and economic perspectives.

[0005] The objective of this invention is achieved through the following technical solution: The first aspect of this invention provides a method for producing 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives, characterized in that an iodine-containing element is used as a catalyst and TBHP (tert-butanol peroxide) is used as a co-oxidizing agent, comprising the following steps: (I) Add methylene succinimide compound, organic amine, elemental iodine, TBHP (tert-butanol peroxide) and organic solvent; (II) Mix the reactants thoroughly, and heat the mixture in air until it reaches 70°C. o Reaction under C; (III) After the reaction is complete, the target product is obtained by column chromatography separation and purification.

[0006] Furthermore, the chemical reaction equations for the synthesis process are shown below: in R 1 Selected from: Hydrogen atom, methyl, hydroxyl, methoxy, phenyl, phenoxy, halogen, nitro, etc.; Organic amines are selected from: Tetrahydroisoquinoline, pyrrole, piperidine, benzylamine, diethylamine, aniline, etc.

[0007] The novel photocatalyst of this invention can be modified by molecular design in the future to change R. 1 By combining the structure of organic amines, the light absorption wavelength is broadened, improving the catalytic reaction efficiency in different wavelength bands; at the same time, the redox potential of the molecule is changed, broadening the application of this compound in the field of catalysis.

[0008] Furthermore, the catalyst is elemental iodine.

[0009] Furthermore, the atmosphere is air.

[0010] Furthermore, one of acetonitrile, ethyl acetate, tert-butanol, methanol, ethanol, and n-propanol, with tert-butanol being the preferred solvent.

[0011] Furthermore, the reaction temperature is 70°C. o C, the reaction time is 1-6 h.

[0012] Further, after the reaction is completed, the separation and purification operation is as follows: the reaction mixture is quenched with water and extracted with dichloromethane. The combined organic extracts are dried with anhydrous sodium sulfate and concentrated by rotary evaporation. The crude product is purified by silica gel column chromatography to obtain 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives, using petroleum ether:ethyl acetate (16:1) as eluent.

[0013] Furthermore, the molar ratio of the compound of structural formula I to the compound of structural formula II is 1 to 3:1, preferably 3:1.

[0014] Furthermore, the molar ratio of the catalyst to the compound of Formula II is 0.1 to 1:1, preferably 0.2:1.

[0015] A second aspect of the present invention provides the catalytic application of 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives, characterized in that the selected specific catalyst R 1 Selected from hydrogen atoms; R 2 Selected from phenyl. The following model reactions are chosen: (I) Anti-Markovnikov addition of styrene to thiophenol; (II) Decarboxylation coupling reaction of phenylacetic acid / indoleacetic acid; (III) Decarboxylation of phenylacetic acid to synthesize imine; (IV) Coupling reaction of thiophenol with tetrahydrofuran.

[0016] The catalytic application of the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative is characterized in that, in a molar ratio, the catalytic reaction template reaction I comprises: styrene, p-chlorobenzylthiophenol, and the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative dissolved in acetonitrile, reacting under visible light irradiation at a wavelength of 455-460 nm at a reaction temperature of 35°C. o C, reaction time is 5 h.

[0017] Furthermore, the chemical reaction equations for the synthesis process are shown below: .

[0018] The catalytic application of the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative is characterized in that, in a molar ratio, the catalytic reaction template reaction I comprises: styrene, p-chlorobenzylthiophenol, and triphenylphosphine; the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative is dissolved in acetonitrile in a molar ratio (1:1:0.2:0.005); and the reaction is carried out under visible light irradiation at a wavelength of 455-460 nm at a reaction temperature of 35°C. o C, reaction time is 5 h.

[0019] Furthermore, the chemical reaction equations for the synthesis process are shown below: .

[0020] The catalytic reaction template reaction II comprises: phenylacetic acid / indoleacetic acid, p-chlorothiophenol, and the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative dissolved in DMSO (dimethyl sulfoxide) at a molar ratio of 1:1:0.01, reacting under visible light irradiation at a wavelength of 455-460 nm at a reaction temperature of 35°C. o C, the reaction time is 12-24 h.

[0021] Furthermore, the chemical reaction equations for the synthesis process are shown below: .

[0022] Furthermore, R 4 Selected from: methyl, halogen, hydroxyl, methoxy, nitro, amino, indole, etc.

[0023] The catalytic reaction template reaction III comprises: naphthaleneacetic acid, an aromatic amine, and the aforementioned 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative dissolved in DMSO (dimethyl sulfoxide) at a molar ratio of 1:1:0.01, reacting under visible light irradiation at a wavelength of 455-460 nm at a reaction temperature of 35°C. o C, the reaction time is 12 h.

[0024] Furthermore, the chemical reaction equations for the synthesis process are shown below: .

[0025] The catalytic reaction template reaction IV comprises: chlorothiophenol and the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative dissolved in THF (tetrahydrofuran) at a molar ratio (1:0.01), reacting under visible light irradiation at a wavelength of 455-460 nm at a reaction temperature of 35°C. o C, the reaction time is 24 h.

[0026] Furthermore, the chemical reaction equations for the synthesis process are shown below: .

[0027] Compared with existing technologies, the present invention has the following advantages and beneficial effects: (I) This invention is the first to adopt a technical solution to construct a novel photocatalyst--3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative in an air atmosphere under the catalysis of iodine-containing elements. The structure is novel and stable and can be stored for a long time without deterioration. (II) A technical solution for constructing a novel photocatalyst—3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives in one step under the catalysis of iodine-containing elements in an air atmosphere. The reaction raw materials are inexpensive and readily available, the reaction has high atom economy, and the reaction operation is simple. Moreover, the one-pot direct selective synthesis of the target product overcomes the huge waste of human, financial and material resources caused by the existing multi-step synthesis method, and saves a lot of research and development time and production cycle. (III) A technical solution for constructing a novel photocatalyst--3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative in one step under the catalysis of iodine-containing elemental in an air atmosphere. The reaction does not require the use of metal catalysts or equivalent metal oxidants, but only requires the use of inexpensive iodine elemental, which reduces environmental pollution, saves raw materials, reduces reaction costs, and is simple to operate and easy to purify. (IV) The novel photocatalyst obtained in this invention—3-benzyl-4-(tetrahydroisoquinolinyl)maleimide framework structure—has great potential for modification, which can broaden the light absorption range and enhance the catalytic ability at different wavelengths. (V) The novel photocatalyst obtained in this invention—3-benzyl-4-(tetrahydroisoquinolinyl)maleimide-based framework structure—has a suitable redox potential and possesses very good catalytic ability, enabling it to catalyze reactions that conventional photocatalysts cannot catalyze. (VI) The novel photocatalyst obtained in this invention—3-benzyl-4-(tetrahydroisoquinolinyl)maleimide framework structure—has excellent catalytic activity advantages. It requires a low loading in the catalytic reaction, and only 0.5%-1% loading is needed to complete the catalytic cycle well. Attached Figure Description

[0028] Figure 1 and Figure 2 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 1, respectively.

[0029] Figure 3 and Figure 4 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 2, respectively.

[0030] Figure 5 and Figure 6 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 3, respectively.

[0031] Figure 7 and Figure 8 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 4, respectively.

[0032] Figure 9 and Figure 10 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 5, respectively.

[0033] Figure 11 and Figure 12 These are the proton and carbon spectra of the target product obtained in Example 6, respectively.

[0034] Figure 13 and Figure 14 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 7, respectively.

[0035] Figure 15 and Figure 16 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 8, respectively.

[0036] Figure 17 and Figure 18 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 9, respectively.

[0037] Figure 19 and Figure 20 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 10, respectively.

[0038] Figure 21 and Figure 22 These are the hydrogen spectrum and carbon spectrum of the target product obtained in Example 11, respectively. Specific implementation methods

[0039] The following examples further illustrate the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are methods that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents and instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially. Example 1

[0040] Add 0.2 mmol of 3-benzylmethyl-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of peroxytert-butanol, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 90% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0041] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 1 and Figure 2 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.46 – 7.42 (m, 2H), 7.39 (dd, J = 5.3, 3.3Hz, 2H), 7.31 (t, J = 7.4 Hz, 3H), 7.26 (d, J = 7.1 Hz, 2H), 7.21 (t, J = 7.2 Hz,1H), 7.18 – 7.15 (m, 2H), 7.12 – 7.09 (m, 1H), 6.95 – 6.91 (m, 1H), 4.86 (s,2H), 3.99 (t, J = 5.9 Hz, 2H), 3.96 (s, 2H), 2.89 (t, J = 5.8 Hz, 2H); 13C NMR (126 MHz, CDCl3) δ 171.57, 167.01, 144.66, 140.12, 133.94,133.07, 132.11, 128.88, 128.81, 128.79, 127.98, 127.25, 126.96, 126.50,126.43, 126.14, 126.04, 102.63, 50.68, 46.65, 29.22, 29.01.

[0042] Based on the above data, the following structure can be derived: . Example 2

[0043] Add 0.2 mmol of 3-(4'-methylbenzylmethyl)-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 85% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0044] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 3 and Figure 4 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.43 (t, J = 7.6 Hz, 2H), 7.38 (d, J = 8.0 Hz, 2H), 7.31 (t, J = 6.8 Hz, 1H), 7.16 (dd, J = 10.8, 5.6 Hz, 4H), 7.11 (d, J = 7.4Hz, 3H), 6.95 (d, J = 6.6 Hz, 1H), 4.87 (s, 2H), 3.99 (t, J = 5.7 Hz, 2H), 3.91(s, 2H), 2.91 (t, J= 5.5 Hz, 2H), 2.31 (s, 3H); 13 C NMR (126 MHz, CDCl3) δ 171.56, 167.07, 144.55, 137.01, 135.91,133.97, 133.13, 132.15, 129.47, 128.85, 128.78, 127.84, 127.20, 126.92,126.48, 126.13, 126.06, 103.11, 50.68, 46.64, 29.26, 28.59, 21.03.

[0045] Based on the above data, the following structure can be derived: . Example 3

[0046] Add 0.2 mmol of 3-(4'-methoxybenzyl)-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of peroxytert-butanol, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 73% yield. The eluent used was petroleum ether and ethyl acetate (10:1).

[0047] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 5 and Figure 6 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.44 (t, J = 7.7 Hz, 2H), 7.38 (d, J = 7.9 Hz, 2H), 7.32 (t, J = 7.3 Hz, 1H), 7.20 – 7.15 (m, 4H), 7.14 – 7.10 (m, 1H), 6.96(d, J = 6.4 Hz, 1H), 6.85 (d, J = 8.5 Hz, 2H), 4.88 (s, 2H), 4.01 (t, J= 5.8 Hz,2H), 3.89 (s, 2H), 3.79 (s, 3H), 2.92 (t, J = 5.8 Hz, 2H); 13 C NMR (126 MHz, CDCl3) δ 171.58, 167.06, 158.16, 144.51, 133.95,133.10, 132.06, 128.91, 128.86, 128.80, 127.22, 126.93, 126.49, 126.13,126.05, 114.19, 103.15, 77.30, 77.04, 76.79, 55.32, 50.70, 46.64, 29.25,28.12.

[0048] Based on the above data, the following structure can be derived: . Example 4

[0049] Add 0.2 mmol of 3-(4'-fluorobenzylmethyl)-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 86% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0050] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 7 and Figure 8 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.44 (t, J = 7.6 Hz, 2H), 7.38 (d, J = 7.8 Hz, 2H), 7.32 (t, J = 7.3 Hz, 1H), 7.24 – 7.20 (m, 2H), 7.17 (d, J = 6.1 Hz, 2H), 7.12 (d, J = 6.8 Hz, 1H), 7.00 (t,J = 8.5 Hz, 2H), 6.93 (d, J = 6.9 Hz, 1H), 4.86(s, 2H), 4.00 (t, J = 5.8 Hz, 2H), 3.92 (s, 2H), 2.91 (t, J = 5.6 Hz, 2H); 13 C NMR (126 MHz, CDCl3) δ 171.51, 166.88, 161.54 (d, J = 244.5 Hz),144.68, 135.68 (d, J = 3.1 Hz), 133.87, 132.92, 132.01, 129.37 (d, J = 7.8 Hz),128.90, 128.81, 127.31, 127.04, 126.57, 126.12, 126.00, 115.59 (d, J = 21.3Hz), 102.32, 50.72, 46.67, 29.21, 28.27.

[0051] Based on the above data, the following structure can be derived: . Example 5

[0052] Add 0.2 mmol of 3-(4'-chlorobenzylmethyl)-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of peroxytert-butanol, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 82% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0053] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 9 and Figure 10 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.44 (t, J= 7.7 Hz, 2H), 7.38 (d, J = 7.5 Hz, 2H), 7.32 (t, J = 7.3 Hz, 1H), 7.28 (d, J = 8.2 Hz, 2H), 7.19 (d, J = 8.5 Hz, 4H), 7.12 (d, J = 6.7 Hz, 1H), 6.94 (d, J = 6.7 Hz, 1H), 4.85 (s, 2H), 4.00 (t, J = 5.7Hz, 2H), 3.92 (s, 2H), 2.92 (t, J = 5.4 Hz, 2H); 13 C NMR (126 MHz, CDCl3) δ 171.45, 166.81, 144.74, 138.56, 133.85,132.87, 132.21, 131.99, 129.30, 128.90, 128.81, 127.33, 127.07, 126.60,126.12, 126.00, 101.92, 50.71, 46.68, 29.22, 28.47.

[0054] Based on the above data, the following structure can be derived: . Example 6

[0055] Add 0.2 mmol of 3-(4'-chlorobenzylmethyl)-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of peroxytert-butanol, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 82% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0056] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 11 and Figure 12 As shown; the structural characterization data are as follows: 1H NMR (500 MHz, CDCl3) δ 7.44 (t, J = 7.7 Hz, 4H), 7.38 (d, J = 7.9 Hz, 2H), 7.32 (t, J = 7.3 Hz, 1H), 7.18 (t, J = 5.6 Hz, 2H), 7.14 (d, J = 7.8 Hz, 3H), 6.94 (d, J = 7.0 Hz, 1H), 4.85 (s, 2H), 4.00 (t, J = 5.8 Hz, 2H), 3.90 (s, 2H), 2.92 (t, J = 5.7 Hz, 2H); 13 C NMR (126 MHz, CDCl3) δ 171.43, 166.80, 144.75, 139.09, 133.85,132.86, 132.00, 131.84, 129.69, 128.89, 128.80, 127.32, 127.07, 126.60,126.12, 126.00, 120.24, 101.84, 50.71, 46.69, 29.22, 28.55.

[0057] Based on the above data, the following structure can be derived: . Example 7

[0058] Add 0.2 mmol of 3-(4'-dimethylaminobenzyl)-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydroisoquinoline, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 72% yield. The eluent used was petroleum ether and ethyl acetate (12:1).

[0059] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 13 and Figure 14 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.44 (t, J = 7.6 Hz, 2H), 7.38 (d, J = 8.3 Hz, 2H), 7.31 (t, J = 6.9 Hz, 1H), 7.20 – 7.10 (m, 5H), 6.99 (d, J = 6.1 Hz, 1H), 6.74 (s, 2H), 4.89 (s, 2H), 4.01 (t, J = 5.2 Hz, 2H), 3.85 (s, 2H), 2.92 (s, 9H); 13 C NMR (126 MHz, CDCl3) δ 171.62, 167.19, 144.37, 134.02, 133.24,132.15, 128.84, 128.79, 128.65, 127.16, 126.87, 126.45, 126.13, 126.10,113.42, 103.77, 50.70, 46.65, 29.29, 27.98.

[0060] Based on the above data, the following structure can be derived: . Example 8

[0061] Add 0.2 mmol of 3-benzylmethyl-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of piperidine, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 90% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0062] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 15 and Figure 16 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.43 (t, J= 7.6 Hz, 2H), 7.38 (d, J = 7.7 Hz, 2H), 7.30 (t, J = 7.6 Hz, 3H), 7.22 (d, J = 7.8 Hz, 3H), 3.89 (s, 2H), 3.65 (d, J =5.1 Hz, 4H), 1.57 (d, J = 4.9 Hz, 6H); 13 C NMR (126 MHz, CDCl3) δ 171.60, 167.14, 145.10, 139.85, 132.23,128.80, 128.64, 127.97, 127.10, 126.27, 126.12, 101.98, 50.06, 29.05, 26.53,24.10.

[0063] Based on the above data, the following structure can be derived: . Example 9

[0064] Add 0.2 mmol of 3-benzylmethyl-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of tetrahydropyrrole, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 hour, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 92% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0065] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 17 and Figure 18 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.45 – 7.41 (m, 2H), 7.38 (d, J = 7.1 Hz, 2H), 7.30 (dd, J = 10.2, 4.5 Hz, 3H), 7.24 (d, J = 7.4 Hz, 2H), 7.19 (t, J= 7.2 Hz,1H), 3.94 (s, 2H), 3.82 (t, J = 6.6 Hz, 4H), 1.90 – 1.85 (m, 4H); 13 C NMR (126 MHz, CDCl3) δ 172.55, 168.08, 145.35, 140.04, 137.17,128.59, 128.58, 128.48, 127.88, 127.50, 126.17, 101.28, 49.79, 41.40, 28.93, 26.44, 24.06.

[0066] Based on the above data, the following structure can be derived: . Example 10

[0067] Add 0.2 mmol of 3-benzylmethyl-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of diethylamine, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 82% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0068] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 19 and Figure 20 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.46 – 7.41 (m, 1H), 7.39 (d, J = 7.3 Hz, 1H),7.32 – 7.27 (m, 1H), 7.22 – 7.18 (m, 1H), 3.87 (s, 1H), 3.57 (q, J = 7.0 Hz, 2H), 1.21 (t, J = 7.0 Hz, 3H); 13C NMR (126 MHz, CDCl3) δ 171.76, 166.73, 143.86, 140.84, 132.27,128.79, 128.68, 127.74, 127.07, 126.21, 126.14, 99.20, 45.89, 28.93, 14.57.

[0069] Based on the above data, the following structure can be derived: . Example 11

[0070] Add 0.2 mmol of 3-benzylmethyl-1-phenyl-pyrrolidine-2,5-dione compound, 0.6 mmol of benzylamine, 0.2 mmol of tert-butanol peroxide, 0.04 mmol of elemental iodine, and 2 ml of tert-butanol solvent to a reaction tube, and incubate at 80 °C. o The reaction was carried out at C for 1 h, monitored by TLC, and stopped after the starting material disappeared. The reaction was quenched by adding 10 ml of water, and extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product in 86% yield. The eluent used was petroleum ether and ethyl acetate (16:1).

[0071] The proton and carbon spectra of the product obtained in this embodiment are as follows: Figure 21 and Figure 22 As shown; the structural characterization data are as follows: 1 H NMR (500 MHz, CDCl3) δ 7.45 – 7.40 (m, 4H), 7.37 (t, J = 7.2 Hz, 2H), 7.33 (d, J = 7.8 Hz, 2H), 7.29 (d, J = 7.3 Hz, 2H), 7.22 (d, J = 7.1 Hz, 3H), 7.19(d, J = 7.5 Hz, 2H), 5.61 (s, 1H), 4.50 (d, J = 6.3 Hz, 2H), 3.75 (s, 2H); 13C NMR (126 MHz, CDCl3) δ 172.47, 167.10, 142.61, 140.36, 137.38,132.12, 129.09, 128.93, 128.78, 128.13, 127.96, 127.17, 127.01, 126.41,125.55, 97.76, 47.70, 27.49.

[0072] Based on the above data, the following structure can be derived: .

[0073] A novel photocatalyst synthesis, applied to photocatalytic reactions, test example 1. ; In a reaction tube, 0.4 mmol of styrene, 0.2 mmol of p-chlorothiophenol, and 0.001 mmol of PC (compound of Example 1) were added sequentially, followed by 2 ml of acetonitrile. The reaction was then placed under visible light at a wavelength of 455-460 nm. The reaction was allowed to proceed for 8 h, and the reaction was monitored by TLC until the reactants were completely reacted. The reaction was quenched by adding water, and the mixture was extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layers were concentrated under reduced pressure and purified by column chromatography to obtain the target product. The eluent used was petroleum ether and ethyl acetate (40:1).

[0074] Synthesis of a novel photocatalyst, applied to photocatalytic reactions, test example 2. ; In a reaction tube, 0.4 mmol of styrene, 0.2 mmol of p-chlorothiophenol, 0.2 mmol of PPh3, and 0.001 mmol of PC (compound of Example 1) were added sequentially, followed by 2 ml of acetonitrile. The reaction was then placed under visible light at a wavelength of 455-460 nm. The reaction was allowed to proceed for 8 h, and the reaction was monitored by TLC until the reactants were completely reacted. The reaction was quenched by adding water, and the mixture was extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layers were concentrated under reduced pressure and purified by column chromatography to obtain the target product. The eluent used was petroleum ether and ethyl acetate (20:1).

[0075] A novel photocatalyst synthesis, applied to photocatalytic reactions, test example 3. ; In a reaction tube, 0.2 mmol of indoleacetic acid, 0.2 mmol of p-chlorothiophenol, 0.2 mmol of cesium carbonate, and 0.001 mmol of PC (compound of Example 1) were added in sequence, followed by 2 ml of DMSO. The reaction was then placed under visible light at a wavelength of 455-460 nm. The reaction was allowed to proceed for 12 h, and the reaction was monitored by TLC until the reactants were completely reacted. The reaction was quenched by adding water, and the mixture was extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product. The eluent used was petroleum ether and ethyl acetate (20:1).

[0076] Synthesis of a novel photocatalyst, applied to photocatalytic reactions, test example 4. ; In a reaction tube, 0.2 mmol of naphthaleneacetic acid, 0.2 mmol of aromatic amine, 0.2 mmol of cesium carbonate, and 0.001 mmol of PC (compound of Example 1) were added in sequence, followed by 2 ml of DMSO. The mixture was placed under visible light at a wavelength of 455-460 nm and reacted for 12 h. The reaction was monitored by TLC until the reactants were completely reacted. The reaction was quenched by adding water, and the mixture was extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product. The eluent used was petroleum ether and ethyl acetate (20:1).

[0077] Synthesis of a novel photocatalyst, applied to photocatalytic reactions, test example 5. ; In a reaction tube, 0.2 mmol of p-chlorothiophenol, 0.2 mmol of cesium carbonate, and 0.001 mmol of PC (compound of Example 1) were added sequentially, followed by 2 ml of tetrahydrofuran. The reaction was then placed under visible light at a wavelength of 455-460 nm. The reaction was allowed to proceed for 12 h, and the reaction was monitored by TLC until the reactants were completely reacted. The reaction was quenched by adding water, and the mixture was extracted three times with 20 ml of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain the target product. The eluent used was petroleum ether and ethyl acetate (30:1).

[0078] To demonstrate the catalytic effect of the catalyst described in this invention, the following three commercially available photocatalysts were selected: Comparative Example 1 The specific implementation method is the same as that in test examples 1-5; the difference is that the compound in test examples 1-5 is replaced with a commercially available photocatalyst (4-CzIPN). Comparative Example 2 The specific implementation method is the same as that in test examples 1-5; the difference is that the compound in test examples 1-5 is replaced with a commercially available photocatalyst (Eosin Y). Comparative Example 3 The specific implementation method is the same as in Test Examples 1-5; the difference is that the compound in Test Examples 1-5 is replaced with a commercially available photocatalyst (Mes-Acr). + ).

[0079] The specific reaction results are shown in Table 1 below:

[0080] As shown in Table 1, under the same reaction conditions, the photocatalyst of this invention produces results that are superior to or comparable to those of commercially available catalysts when used to carry out the above reactions. In particular, Test Examples 1, 2, and 5 show better results than commercially available catalysts, while Test Examples 3 and 4 show slightly lower results than commercially available catalysts, but still maintain superior catalytic performance.

Claims

1. A novel photocatalyst, a 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative, characterized in that, Its general formula is Formula I: I in R 1 Selected from: Hydrogen atom, methyl, hydroxyl, methoxy, phenyl, phenoxy, halogen, nitro, etc.; Organic amines are selected from: Tetrahydroisoquinoline, pyrrole, piperidine, benzylamine, diethylamine, aniline, etc.; The novel photocatalyst of this invention can be molecularly designed by analyzing molecular fluorescence properties to modify R. 1 By combining with different amines, the light absorption wavelength can be broadened, thereby improving the catalytic reaction efficiency in different wavelength bands; at the same time, the redox potential of the molecule can be changed, thus broadening the application of the compound in the field of catalysis.

2. A second aspect of the present invention provides a method for preparing 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives, characterized in that, Using iodine-containing elemental as a catalyst and TBHP (tert-butanol peroxide) as a co-oxidizing agent, the following steps are included: 。 3. A synthetic method as claimed in the claims (I) Add methylene succinimide compound, organic amine, elemental iodine, TBHP (tert-butanol peroxide) and organic solvent; (II) Mix the reactants thoroughly and heat them in air. (III) Purify to obtain the product.

4. The method for preparing the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative according to claim 1, characterized in that, The molar ratio of the methylene succinimide compound, organic amine, elemental iodine, and TBHP is 1:2:0.2:1; the organic solvent is one of acetonitrile, ethyl acetate, tert-butanol, methanol, ethanol, and n-propanol. The reaction temperature is 70°C. o C, the reaction time is 3-6 h; The post-processing includes: quenching the reaction mixture with water after the reaction is complete, extracting with dichloromethane, drying the combined organic extracts with anhydrous sodium sulfate, concentrating by rotary evaporation, purifying the crude product by silica gel column chromatography using petroleum ether:ethyl acetate (20:1) as the eluent.

5. A third aspect of the present invention provides the catalytic application of 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives, characterized in that the selected R 1 Selected from hydrogen atoms. The following model reactions are chosen: (I) Anti-Markovnikov addition of styrene and thiophenol (II) Decarboxylation coupling reaction of phenylacetic acid / indoleacetic acid (III) Decarboxylation of phenylacetic acid to synthesize imine (IV) Coupling reaction of thiophenol with tetrahydrofuran.

6. The catalytic application of the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative, characterized in that, The catalytic reaction template reaction I comprises: styrene, p-chlorothiophenol, and 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives dissolved in acetonitrile at a molar ratio (1:1:0.005), and reacted under visible light irradiation at a wavelength of 455-460 nm. 。 7. The catalytic application of the 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivative, characterized in that, The catalytic reaction template reaction I comprises, by molar ratio, styrene, p-chlorothiophenol, triphenylphosphine, and 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives dissolved in acetonitrile, and reacted under visible light irradiation at a wavelength of 455-460 nm: 。 8. The catalytic template reaction II includes: Phenylacetic acid / indoleacetic acid, p-chlorothiophenol, and 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives dissolved in DMSO (dimethyl sulfoxide) at a molar ratio of 1:1:0.01 reacted under visible light irradiation at a wavelength of 455-460 nm. 。 9. The catalytic template reaction III includes: Naphthaleneacetic acid, aromatic amines, and 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives dissolved in DMSO (dimethyl sulfoxide) at a molar ratio of 1:1:0.01 reacted under visible light irradiation at a wavelength of 455-460 nm. 。 10. The catalytic template reaction V includes: p-Chlorophenonethiophenol and 3-benzyl-4-(tetrahydroisoquinolinyl)maleimide derivatives were dissolved in THF (tetrahydrofuran) at a molar ratio (1:0.01) and reacted under visible light irradiation at a wavelength of 455-460 nm: 。

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