CN105568312B - A kind of method that Indirect Electro catalyzes and synthesizes 2 aryl pyrrole compounds - Google Patents

Abstract

The invention provides a method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds. The method uses aromatic halides, pyrroles and their derivatives as raw materials, uses imidazole ionic liquids as electrolytes, and uses aprotic polar solvents as reaction solvents. , The PDI compound of the 10-perylenetetracarboxylic acid imide structural unit is the medium of indirect electrocatalysis, and the C-2-position arylated pyrrole is synthesized by a constant current or constant potential electrolysis method without the use of a metal catalyst and the addition of a base. and its derivatives. The invention has the characteristics of simple and fast operation, mild reaction conditions, no need to add metal catalysts, no need for strong alkaline reaction conditions, etc. It has broad application prospects in the synthesis of natural products, medicines and materials, and is in line with the development of "green chemical synthesis industry" requirements.

Description

A kind of indirect electrocatalytic synthesis method of 2-arylpyrrole compound

technical field

The present invention relates to the fields of organic chemistry and electrochemical synthesis, in particular to a method for direct C-2 arylation of pyrrole and its derivatives through indirect electroreduction reaction using small organic molecule PDI as a medium .

technical background

Functionalized pyrrole derivatives widely exist in many active natural products and synthetic drugs, and can also be used as synthetic intermediates in organic synthesis and polymer material preparation (Kern, J.C.; Terefenko, E.; Trybulski, E.; Berrodin, T.J.; Cohen, J.; Winneker, R.C.; Yudt, M.R.; Zhang, Z.; Zhu, Y.; Zhang, P. Bioorg. Med. Chem. Lett. 2010, 20, 4816.). Therefore, how to efficiently and quickly synthesize functionalized pyrrole derivatives has attracted extensive attention of researchers.

In recent years, a large number of literatures have reported the synthesis of functionalized pyrrole and its derivatives through the direct arylation reaction of C-H activation at the C-2 position of pyrrole. However, the existing methods usually need to be realized under the catalysis of transition metal catalysts. Commonly used catalysts mainly include palladium ((a) Cho, B.S.; Bae, H.J.; Chung, Y.K.J Org Chem2015, 80, 5302. (b) Bernhammer, J.C.; Huynh, H.V.Organometallics 2014, 33, 1266. (c) Zhao, L.; Bruneau, C.; Doucet, H. ChemCatChem 2013, 5, 255. (d) Xu, Y.; Zhao, L.; .(e) Islam, S.; Larrosa, I. Chem Eur J 2013, 19, 15093. (f) Roy, D.; Mom, S.; Royer, S.; Lucas, D.; Hierso, J.- C.; Doucet, H. ACSCatal. 2012, 2, 1033. (g) Ghosh, D.; Lee, H. M. Org. Lett. 2012, 14, 5534. (h) Bensaid, S.; Doucet, H. ChemSusChem 2012 , 5, 1559. (i) Sezen, B.; Sames, D.J.Am.Chem.Soc.2003, 125, 5274.), rhodium ((a) Ueda, K.; Amaike, K.; Maceiczyk, R.M.; Itami , K.; Yamaguchi, J.J.Am.Chem.Soc.2014, 136, 13226. (b) Ackermann, L.; Lygin, A.V.Org Lett. 2011, 13, 3332.), copper (Honraedt, A.; Raux, M.-A.; Le Grognec, E.; Jacquemin, D.; Felpin, F.-X. Chem. Commun. 2014, 50, 5236.) and cobalt (Punji, B.; Song, W.; Shevchenko, G.A.; Ackermann, L. Chem.-Eur. J. 2013, 19, 10605.). There are only a few literature reports that do not require metal catalysts and use strong base as the medium for synthesis ((a) Vakuliuk, O.; Koszarna, B.; Gryko, D.T.Adv.Synth.Catal.2011,353,925. (b) Vakuliuk , O.; Koszarna, B.; Gryko, D.T. Synthesis 2011, 2833. (c) Vakuliuk, O.; Gryko, D.T. Eur. J. Org. Chem. 2011, 2854.). However, most of the reported synthetic methods need to be carried out under high temperature (120°C-150°C) or strong alkali conditions, and the reaction time is long. Therefore, it is of great theoretical significance and potential application prospect to develop a direct arylation method of pyrrole and its derivatives with high efficiency, mild reaction conditions, process safety and environmental friendliness.

3,4,9,10-perylenetetracarboxylic imide (PDI, the structure shown in the following formula) is a kind of commonly used fluorescent dyes. Recently, it has been reported that such compounds can be used as photocatalysts for visible light-catalyzed dehalogenation of aromatic halides and C-C coupling reactions of aromatic halides with pyrrole (Ghosh, I.; Ghosh, T.; Bardagi, J.I.; Konig, B. Science 2014, 346, 725.). In addition, studies on the electrochemical behavior of PDI compounds have shown that this type of compound usually has two reversible oxidation-reduction pairs, and the reduction potential is low, so it is easy to be reduced. However, there is no research report on the application of PDI compounds in electrocatalytic organic synthesis reactions. Therefore, based on the advantages of high selectivity and mild reaction conditions of the indirect electrocatalytic organic synthesis method, combined with the electrochemical properties of PDI compounds, we consider using PDI as a medium for indirect electrocatalytic organic synthesis reactions, and invented the aromatic A synthetic method for synthesizing 2-arylated pyrrole derivatives through indirect electrocatalytic reduction reaction of halides, pyrrole and its derivatives as raw materials.

Structural formula of PDI compounds

The present invention is a research funded by the National Natural Science Foundation of China (21272282).

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the existing direct C-2 arylation method of pyrrole and its derivatives, and provide a kind of indirect electrocatalytic synthesis with mild reaction conditions, fast reaction speed, high selectivity and environmental friendliness Method for 2-arylpyrroles. It uses aromatic halides, pyrrole and its derivatives as raw materials, organic small molecule PDI as a medium, and electrons as a clean reducing agent, without using metal catalysts and adding alkalis.

The invention is an efficient method for direct arylation of the C-2 position of pyrrole and its derivatives, using aryl halides, pyrrole and their derivatives as reaction raw materials, using imidazole ionic liquids as electrolytes, and using aprotic The polar solvent is the reaction solvent, and at room temperature, the PDI compound with the structural unit of 3,4,9,10-perylenetetracarboxylic acid imide is used as a medium to synthesize C- 2-arylated pyrrole and its derivatives.

The reaction involved in the present invention can be represented by the following general formula:

Wherein X is selected from chlorine, bromine or iodine; the aromatic ring of the aromatic halide is a benzene ring, which can be 2-substituted or 4-substituted; R ₁ is an electron-withdrawing substituent; R ₂ is selected from H, methyl or phenyl substituted base.

The specific process of the present invention is: when using the H-type split electrolytic cell to carry out the reaction, the aromatic halide, the reaction medium PDI, the supporting electrolyte, the solvent, and pyrrole and its derivatives are sequentially added to the cathode chamber of the electrolytic cell, and the LiCl, the supporting Electrolyte, solvent, and pyrrole and its derivatives are added to the anode chamber in sequence, and the cathode and anode are respectively inserted (for the constant potential reaction, the cathode chamber also needs to be inserted into the Ag/AgNO ₃ (CH ₃ CN solution) reference electrode), under the condition of stirring at room temperature Carry out constant current or constant potential electrolytic reaction to consume electricity 1F/mol-10F/mol; when using an undivided single-cell electrolytic cell for the reaction, the aromatic halogenated compound, the reaction medium PDI, the supporting electrolyte, the solvent, and pyrrole and its derivatives Sequentially add to the electrolytic cell, insert the cathode and anode (for the constant potential reaction, also need to insert the Ag/AgNO ₃ (CH ₃ CN solution) reference electrode), and carry out the constant current or constant potential electrolysis reaction under the condition of stirring at room temperature until the power consumption 1F/mol-10F/mol. After the electrolysis, the reaction mixture was separated and purified to obtain a C-2 arylated pyrrole compound.

The method of the present invention is described in further detail below

1) The aromatic halides described in the present invention can be aryl iodides, aryl bromides or aromatic chlorides; the aromatic ring substituents can be acetyl, ester, cyano and other electron-withdrawing substituents, but not only limited to these substituents.

2) The pyrrole and its derivatives described in the present invention can be N-substituted or unsubstituted, and the substituent can be methyl or phenyl; the molar ratio of the pyrrole to the aromatic halide is 5:1 to 50 :1, preferably 20:1-50:1. It should be noted that during the actual reaction, only the pyrrole added to the cathode chamber participates in the target reaction, and the ratio range of pyrrole and aryl halide refers to the part added to the cathode chamber. The purpose of adding pyrrole to the anode chamber is to promote the electrooxidation reaction in the anode chamber. Only in this way can the electroreduction reaction in the cathode chamber proceed smoothly, and there is no precise requirement for the amount of pyrrole added to the anode chamber.

3) The solvent used in the present invention is an aprotic polar solvent, which can be N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and acetonitrile.

4) The ionic liquid used in the present invention is a disubstituted or trisubstituted imidazole type ionic liquid, which can be 1,3-dialkyl substituted or 1,2,3-trialkyl substituted imidazole bistrifluoromethanesulfonimide salt, or 1,3-dialkyl-substituted or 1,2,3-trialkyl-substituted imidazolium tetrafluoroborate.

5) In the method of the present invention, the reaction is carried out at room temperature, and the method of indirect electrocatalysis is adopted, which can be the method of constant current electrolysis or the method of constant potential electrolysis; the current of the constant current electrolysis method is preferably 1mA-20mA; The constant potential electrolysis method uses Ag/AgNO ₃ (CH ₃ CN solution) as a reference electrode, and the electrode potential is preferably -1V to -9V; the reaction requires power consumption of 1F/mol to 10F/mol.

6) The method of the present invention is characterized in that the electrolytic cell used can be an undivided single-cell electrolytic cell or an H-type split electrolytic cell; the H-type split electrolytic cell is split with a G4 sand core plate. The H-type split electrolytic cell can be fired with reference to the literature (J.Am.CCCm.CCC.2C15C 13CC CC16-CC1C).

C) method according to the present invention, when carrying out electrolysis reaction in undivided single cell electrolytic cell, used negative electrode (working electrode) is glassy carbon electrode or platinum plate electrode, and anode (counter electrode) is graphite rod electrode, Zinc sheet electrode or iron sheet electrode; when reacting in the H-type split electrolytic cell, the cathode (working electrode) used is a glassy carbon electrode or a platinum sheet electrode, and the anode (counter electrode) is a graphite rod electrode.

C) The medium of the indirect electrocatalysis used in the present invention is 3,4,9,10-perylenetetracarboxylic acid imide (PDI) compound, its structure is shown in the following formula:

Where R can be unsubstituted or substituted phenyl, and the substituent is selected from monosubstituted methyl or methoxy; R' is selected from linear or branched alkyl, cyclohexyl, or substituted or unsubstituted phenyl , the substituent can be monosubstituted or polysubstituted methyl, isopropyl or methoxy; the molar ratio of PDI to substrate aryl halide is 1:4C to 1:4, preferably 1:1C-1: 4.

The synthesis method of the indirect electrocatalytic C-2 arylated pyrrole and its derivatives provided by the present invention has not been reported in the literature, and has the characteristics of simple operation, mild reaction conditions, simple and easy separation of products, safe reaction process and environmental friendliness. . The indirect electrocatalytic medium PDI used in this method is a common industrial dye, which is stable and easy to synthesize. In addition, compared with the same type of reactions reported in the literature, this method does not require the use of metal catalysts, does not need to be carried out under strong alkaline conditions, and uses electrons as clean reducing agents with less environmental pollution. The organic electrochemical synthesis is carried out at normal temperature and normal pressure, and the reaction can be terminated and started at any time, and the reaction can have better selectivity by controlling the electrode potential. These characteristics effectively improve the controllability of the reaction, provide an alternative method for the preparation of natural products, drugs and materials, and have broad prospects in the development of "green chemical synthesis industry".

detailed description

Below in conjunction with embodiment the present invention will be further described.

Embodiment 1: the synthesis of N-methyl-(2-(4-acetyl) phenyl)-pyrrole

40mg (0.2mmol) 4-bromoacetophenone, 4mg (0.005mmol) N,N'-bis(2,6-diisopropylphenyl)-3,4,9,10-perylenetetracarboxylic Imine was added to the cathode chamber of the H-type split reaction cell equipped with a glassy carbon working electrode (10mm×40mm), and 20mg (0.5mmol) lithium chloride was added to the anode chamber equipped with a glassy carbon rod counter electrode. Add 10 mL of 0.15 mol/L 1-methyl-3-ethylimidazole bistrifluoromethanesulfonimide/dimethyl sulfoxide electrolyte solution into the two electrode chambers respectively. Add 450 μL (5 mmol) N-methylpyrrole to the cathode chamber, and 90 μL (1 mmol) N-methylpyrrole to the anode chamber. Set the current value to 5mA, constant current electrolysis, and stop the reaction after the reaction passes through the electricity of 10F/mol. After the reaction, 20 mL of water was added to the catholyte, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain N-methyl- (2-(4-acetyl)phenyl)-pyrrole 32 mg, yield 60%.

Add 50mg (0.2mmol) 4-iodoacetophenone, 11mg (0.02mmol) N,N'-diphenyl-3,4,9,10-perylenetetracarboximide to the glassy carbon working electrode (10mm×40mm) H-type split reaction cell cathode chamber, 20mg (0.5mmol) lithium chloride was added to the anode chamber equipped with a glassy carbon rod counter electrode. Add 10 mL of 0.15 mol/L 1,3-bis-methylimidazole bistrifluoromethanesulfonimide/dimethyl sulfoxide electrolyte solution into the two electrode chambers respectively. Add 900 μL (10 mmol) N-methylpyrrole to the cathode chamber, and 90 μL (1 mmol) N-methylpyrrole to the anode chamber. Set the current value to 5mA, constant current electrolysis, and stop the reaction after the reaction passes through the electric quantity of 5F/mol. After the reaction, 20 mL of water was added to the catholyte, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain N-methyl- (2-(4-acetyl)phenyl)-pyrrole 32 mg, yield 80%.

¹ H NMR (400MHz, CDCl ₃ ) δ8.01(d, J=8.2Hz, 2H), 7.53(d, J=8.2Hz, 2H), 6.80(s, 1H), 6.38(d, J=1.6Hz ,1H),6.26(t,J=2.7Hz,1H),3.75(s,3H),2.65(s,3H); ¹³ C NMR(101MHz,CDCl ₃ )δ197.6,137.9,134.9,133.4,128.6,128.0 ,125.3,110.2,108.4,35.5,26.6; EI-MS(70eV),m/z(%):199[M] ⁺ ,184(100)[M-CH ₃ ] ⁺ ,156(47)[M- CH ₃ CO] ⁺ ,128(20),77(15).

Embodiment 2: the synthetic method of N-methyl-(2-(2-cyano) phenyl) pyrrole

28mg (0.2mmol) 2-chlorobenzonitrile, 33mg (0.05mmol) N,N'-bis(2,4,6-trimethylphenyl)-3,4,9,10-perylenetetracarboxylic Diimine was added to the cathode chamber of the H-type split reaction cell equipped with glassy carbon working electrode (10mm×40mm) and Ag/AgNO ₃ (0.01M CH ₃ CN solution) reference electrode, and 20mg (0.5mmol) Lithium chloride is added to the anode chamber with a glassy carbon rod counter electrode. Add 10 mL of 0.15 mol/L 1-ethyl-2,3-dimethylimidazolium bistrifluoromethanesulfonimide/acetonitrile electrolyte solution into the two electrode chambers respectively. Add 450 μL (5 mmol) N-methylpyrrole to the cathode chamber, and 90 μL (1 mmol) N-methylpyrrole to the anode chamber. The constant potential electrolysis is carried out under the condition of -9V relative to the reference electrode, and the reaction is stopped after passing through the electric quantity of 1F/mol. After the reaction, 20 mL of water was added to the reaction liquid, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain N-methyl- (2-(2-cyano)phenyl)pyrrole 23 mg, yield 64%.

Add 36mg (0.2mmol) 2-bromobenzonitrile, 11mg (0.02mmol) N,N'-bis(3-pentyl)-3,4,9,10-perylenetetracarboximide to the Glassy carbon working electrode (10mm × 40mm) H-type split reaction cell cathode chamber, 20mg (0.5mmol) lithium chloride was added to the anode chamber equipped with glassy carbon rod counter electrode. Add 10 mL of 0.15 mol/L 1-methyl-3-ethylimidazole bistrifluoromethanesulfonimide/N,N-dimethylacetamide electrolyte solution into the two electrode chambers respectively. Add 90 μL (1 mmol) N-methylpyrrole to the cathode chamber, and 90 μL (1 mmol) N-methylpyrrole to the anode chamber. Set the current value to 1mA, constant current electrolysis, and stop the reaction after the reaction passes through 2F/mol of electricity. After the reaction, 20 mL of water was added to the reaction liquid, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain N-methyl- (2-(2-cyano)phenyl)pyrrole 27 mg, yield 74%. inside

¹ H NMR (400MHz, CDCl ₃ ) δ7.77(d, J=7.7Hz, 1H), 7.63(t, J=7.7Hz, 1H), 7.49–7.42(m, 2H), 6.82(s, 1H) ,6.50–6.36(m,1H),6.28(t,J=2.9Hz,1H),3.64(s,3H); ¹³ C NMR(101MHz,CDCl ₃ )δ136.9,133.5,132.3,130.9,129.9,127.4, 124.8,118.6,112.8,111.5,108.3,34.8; EI-MS(70eV),m/z(%):182(72)[M] ⁺ ,181(100)[MH] ⁺ .

Embodiment 3: the synthesis of 4-(N-methyl-2-pyrrolyl)-methyl benzoate

43mg (0.2mmol) methyl 4-bromobenzoate, 11mg (0.02mmol) N,N'-dicyclohexyl-3,4,9,10-perylenetetracarboximide, 10mL of 0.15mol/L The electrolyte solution of 1-methyl-3-ethylimidazolium tetrafluoroborate/N,N-dimethylformamide, 900μL (10mmol) N-methylpyrrole were sequentially added to the glassy carbon working electrode (10mm× 40mm) and a single-port electrolytic cell with an iron counter electrode. Set the current value to 10mA, constant current electrolysis, and stop the reaction after the reaction passes through 5F/mol of electricity. After the reaction was completed, 20 mL of water was added to the reaction liquid, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain 4-(N- Methyl-2-pyrrolyl)-benzoic acid methyl ester 36 mg, yield 85%.

¹ H NMR (400MHz, CDCl ₃ ) δ8.09(d, J=7.9Hz, 2H), 7.50(d, J=7.9Hz, 2H), 6.79(s, 1H), 6.45–6.31(m, 1H) ,6.32–6.12(m,1H),3.96(s,3H),3.74(s,3H); ¹³ C NMR(101MHz,CDCl ₃ )δ167.0,137.8,133.5,130.9,129.8,127.9,125.1,110.1,108.3 ,52.1,35.4; EI-MS (70eV), m/z(%):215(95)[M] ⁺ ,184(100)[M-CH ₃ O] ⁺ ,156(45)[M-CH ₃ COO] ⁺ .

Embodiment 4: the synthesis of 4-(N-methyl-2-pyrrolyl) benzonitrile

36mg (0.2mmol) 4-bromobenzonitrile, 12mg (0.02mmol) N,N'-bis(4-methoxyphenyl)-3,4,9,10-perylenetetracarboximide, 10 mL of 0.15 mol/L 1,2,3-trimethylimidazolium tetrafluoroborate/dimethyl sulfoxide electrolyte solution, 900 μL (10 mmol) N-methylpyrrole were sequentially added to the platinum mesh working electrode ( 10mm×40mm) and a single-port electrolytic cell with a zinc sheet counter electrode. Set the current value to 20mA, constant current electrolysis, and stop the reaction after passing through the electric quantity of 5F/mol. After the reaction was completed, 20 mL of water was added to the reaction solution, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain 4-(N- Methyl-2-pyrrolyl)benzonitrile 27 mg, yield 75%.

¹ H NMR (400MHz, CDCl ₃ ) δ7.69(d, J=8.2Hz, 2H), 7.53(d, J=8.2Hz, 2H), 6.81(s, 1H), 6.41–6.34(m, 1H) ,6.26(t,J=3.1Hz,1H),3.74(s,3H); ¹³ C NMR(101MHz,CDCl ₃ )δ137.7,132.6,132.3,132.3,128.3,125.9,119.1,110.8,109.7,108.6,35.5 ; EI-MS (70eV), m/z (%): 182 (100) [M] ⁺ .

Embodiment 5: the synthesis of 4-pyrrolyl acetophenone

40mg (0.2mmol) 4-bromoacetophenone, 17mg (0.02mmol) N,N'-bis(2,6-diisopropylphenyl)-5,12-diphenyl-3,4,9 , 10-perylenetetracarboximide, 10mL of 0.15mol/L 1-methyl-3-ethylimidazolium bistrifluoromethanesulfonimide/N,N-dimethylformamide electrolyte solution, 670μL (10mmol) pyrrole was sequentially added to a single-port electrolytic cell equipped with a glassy carbon working electrode (10mm×40mm), a zinc counter electrode and a Ag/AgNO ₃ (0.01M CH ₃ CN solution) reference electrode. The constant potential electrolysis is carried out under the condition of -1V relative to the reference electrode, and the reaction is stopped after passing through the electric quantity of 5F/mol. After the reaction, 20 mL of water was added to the reaction liquid, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain 4-pyrrolylbenzene Ethanone 22mg, yield 60%.

¹ H NMR (400MHz,DMSO-d ₆ )δ11.53(s,1H),7.93(d,J=8.3Hz,2H),7.75(d,J=8.3Hz,2H),6.97(s,1H) ,6.72(s,1H),6.19(s,1H),2.56(s,3H); ¹³ C NMR(101MHz,DMSO-d ₆ )δ197.3,137.7,133.9,130.5,129.5,123.3,121.6,110.2,108.5 ,27.0; EI-MS(70eV), m/z(%):185(85)[M] ⁺ ,170(100)[M-CH ₃ ] ⁺ ,142(43)[M-CH ₃ CO] ⁺ .

Embodiment 6: the synthesis of 2-pyrrolylbenzonitrile

34mg (0.2mmol) 2-chlorobenzonitrile, 18mg (0.02mmol) N,N'-bis(2,6-diisopropylphenyl)-5,12-bis(4-methylphenyl) -3,4,9,10-perylenetetracarboximide, 10mL of 0.15mol/L 1-methyl-3-ethylimidazolium bistrifluoromethanesulfonimide/dimethylsulfoxide electrolyte solution , 670μL (10mmol) of pyrrole was sequentially added to a single-port electrolytic cell equipped with a glassy carbon working electrode (10mm×40mm) and a graphite rod counter electrode. Set the current value to 4mA, constant current electrolysis, and stop the reaction after the reaction passes through the electric quantity of 2F/mol. After the reaction, 20 mL of water was added to the reaction solution, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain 2-pyrrolylbenzene Formaldehyde 22 mg, yield 65%.

¹ H NMR (400MHz,DMSO-d ₆ )δ11.50(s,1H),7.81(d,J=7.7Hz,1H),7.70(s,2H),7.36(d,J=3.6Hz,1H) ,7.00(s,1H),6.83(s,1H),6.23(s,1H); ¹³ C NMR(101MHz,DMSO-d ₆ )δ136.0,134.9,133.9,127.7,126.9,126.6,121.7,120.0,110.1 ,110.0,106.9,40.4,40.2,40.0,39.8,39.5,39.3,39.1; EI-MS(70eV), m/z(%):168(100)[M] ⁺ .

Embodiment 7: the synthesis of 2-(N-phenylpyrrolyl) benzonitrile

34mg (0.2mmol) 2-chlorobenzonitrile, 18mg (0.02mmol) N,N'-bis(2,6-diisopropylphenyl)-5,12-bis(4-methoxyphenyl )-3,4,9,10-perylenetetracarboximide, 10mL of 0.15mol/L 1-methyl-3-ethylimidazole bistrifluoromethanesulfonimide/dimethyl sulfoxide electrolyte Solution, 1.0g (5mmol) N-phenylpyrrole was sequentially added to a single-hole electrolytic cell equipped with a glassy carbon working electrode (10mm×40mm) and an iron sheet counter electrode. Set the current value to 4mA, constant current electrolysis, and stop the reaction after the reaction passes through the electric quantity of 2F/mol. After the reaction, 20 mL of water was added to the reaction liquid, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain 2-(N- 39mg of phenylpyrrolyl)benzonitrile, yield 80%.

¹ H NMR (400MHz, DMSO-d ₆ ) δ7.82(d, J=7.7Hz, 1H), 7.54(t, J=7.6Hz, 1H), 7.42(t, J=7.6Hz, 1H), 7.39 –7.33(m, 2H), 7.33–7.23(m, 2H), 7.18–7.08(m, 3H), 6.60(d, J=2.0Hz, 1H), 6.44–6.37(m, 1H). ¹³ C NMR (101MHz,DMSO-d ₆ )δ139.7,136.5,134.0,133.1,131.3,129.7,129.0,128.2,127.3,125.9,125.6,118.7,113.9,111.7,110.0; EI-MS (70eV), m/z (% ):244(100)[M] ⁺ .

Embodiment 8: the synthesis of 4-(N-phenyl-pyrrolyl) acetophenone

Add 50mg (0.2mmol) 4-iodoacetophenone, 14mg (0.02mmol) N,N'-dihexyl-3,4,9,10-perylenetetracarboximide to a glassy carbon working electrode ( 10mm × 40mm) of the cathode chamber of the H-type split reaction cell, 20mg (0.5mmol) lithium chloride was added to the anode chamber equipped with a glassy carbon rod counter electrode. Add 10 mL of 0.15 mol/L 1-methyl-3-ethylimidazole bistrifluoromethanesulfonimide/dimethyl sulfoxide electrolyte solution into the two electrode chambers respectively. Add 1.0 g (5 mmol) N-phenylpyrrole to the cathode chamber, and 0.2 g (1 mmol) N-phenylpyrrole to the anode chamber. Set the current value to 2mA, constant current electrolysis, and stop the reaction after passing through the electric quantity of 5F/mol. After the reaction, 20 mL of water was added to the catholyte, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure and purified by silica gel column chromatography to obtain 4-(N- Phenyl-pyrrolyl)acetophenone 39 mg, yield 75%.

¹ H NMR (400MHz, CDCl ₃ ) δ7.81(d, J=7.9Hz, 2H), 7.42–7.32(m, 3H), 7.21(t, J=7.8Hz, 4H), 7.01(s, 1H) ,6.66–6.54(m,1H),6.42(s,1H),2.57(s,3H); ¹³ C NMR(101MHz,CDCl ₃ )δ197.6,140.3,137.5,134.5,132.6,129.3,128.3,127.7,127.1 ,126.0,125.8,112.3,109.8,26.5; EI-MS(70eV),m/z(%):261(100)[M] ⁺ ,246(92)[MH ₃ ] ⁺ ,218(90)[M -CH ₃ CO] ⁺ .

Claims (7)

1. A method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds, using aromatic halides and pyrrole and derivatives thereof as raw materials, with imidazole ionic liquids as electrolytes, and with aprotic polar solvents as reaction solvents, It is characterized in that: at room temperature, the PDI compound with the structural unit of 3,4,9,10-perylenetetracarboxylic acid imide is used as the medium of indirect electrocatalysis, without using metal catalyst and adding alkali, through constant current Or the method of constant potential electrolysis consumes 1F/mol to 10F/mol of pyrrole and derivatives thereof synthesized at C-2 position arylation; the aromatic halide is selected from aryl iodide, aryl bromide or aromatic chloride , wherein the aromatic ring is a 2-substituted or 4-substituted benzene ring, and the substituent is an electron-withdrawing substituent; the pyrrole and its derivatives are N-substituted or unsubstituted, and the substituent is methyl or phenyl; The imidazole ionic liquid is a disubstituted or trisubstituted imidazole ionic liquid; the molar ratio of pyrrole and its derivatives to aromatic halides is 5:1 to 50:1. 2. The method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds according to claim 1, wherein the electron-withdrawing substituent is selected from acetyl, ester or cyano. 3. the method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds as claimed in claim 1, characterized in that: the aprotic polar solvent is selected from N, N-dimethylformamide, N, N - Dimethylacetamide, dimethylsulfoxide or acetonitrile. 4. The method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds as claimed in claim 1, characterized in that: the imidazole ionic liquid is selected from 1,3-dialkyl substitution or 1,2,3- Trialkyl-substituted imidazole bistrifluoromethanesulfonimide salt, or 1,3-dialkyl-substituted or 1,2,3-trialkyl-substituted imidazole tetrafluoroborate. 5. the method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds as claimed in claim 1, is characterized in that: the electric current of described constant current electrolysis method is 1mA-20mA; Described constant potential electrolysis method uses Ag/AgNO ₃ is a reference electrode, and the electrode potential is -1V to -9V. 6. The method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds as claimed in claim 1, characterized in that: the medium of the indirect electrocatalysis is 3,4,9,10-perylenetetracarboxylic acid imide The structure of amine PDI compounds is shown in the figure below: Among them: R is selected from unsubstituted or substituted phenyl, and the substituent is selected from monosubstituted methyl or methoxy; R' is selected from 3-pentyl, straight chain alkyl with 5-8 carbons, cyclohexyl , or substituted or unsubstituted phenyl, and the substituents are selected from monosubstituted or polysubstituted methyl, isopropyl or methoxy. 7. The method for indirect electrocatalytic synthesis of 2-arylpyrrole compounds according to claim 1 or 6, wherein the molar ratio of PDI to the substrate aryl halide is 1:40 to 1:4.