A method for synthesizing N-(substituted benzyl) arylamine compounds under visible light conditions

Abstract

The application discloses a method for synthesizing N-(substituted benzyl) arylamine compounds under visible light conditions, and the synthesis process of the method is as follows: (E)-N,1-diarylformimidate, 3CzEPAIPN and N,N-diisopropylethylamine are added in a glass reaction container in proportion, CH3CN is used as a solvent, and magnetic stirring is carried out at room temperature under blue light irradiation for 3-4 hours; after the reaction is completed, a crude product is obtained through rotary evaporation under reduced pressure; and finally, the N-(substituted benzyl) arylamine compound is obtained through column chromatography separation and purification. The application innovatively uses a metal-free catalytic system, avoids using a strong oxidant, and exhibits good selectivity and atomic economy under mild reaction conditions, thereby providing a new strategy for C-C bond activation with application prospects in the field of green synthesis.

Description

Technical Field

[0001] This invention belongs to the field of organic synthetic chemistry, specifically relating to a novel method for synthesizing N-(substituted benzyl)aromatic amine compounds by Schiff base reduction coupling and C / C bond cleavage under visible light conditions. Background Technology

[0002] Amines are an important class of bioactive chemical substances found in many pharmaceuticals, agrochemicals, and natural products (Organic & Biomolecular Chemistry, 2020, 18(30): 5832-5837.). Examples include anti-Parkinson's disease drugs, anti-Trekking disease drugs, and antihistamines for treating rhinitis (Catalysis Communications, 2020, 136:105906; Organic Chemistry Frontiers, 2023, 10(3): 730-744.). Various synthetic methods have been established to construct and functionalize amines, among which reductive amination is considered one of the most universal and effective methods (Organic Letters, 2018, 20(4): 905-908; ACS Catalysis, 2017, 7(12): 8152-8158.). To achieve efficient and highly selective reductive amination, researchers have strived to find suitable reduction methods. However, these methods still have limitations, such as the use of strong reducing agents (metal borohydrides, formic acid, ammonium formate, and silanes, etc.) and precious metal catalysts (iridium and rhodium, etc.), as well as high-temperature conditions (Journal of Molecular Liquids, 2014, 196: 208-210; Chemistry-A European Journal, 2017, 23(9): 2217-2224; Asian Journal of Organic Chemistry, 2018, 7(9): 1815-1818; Chemical Communications, 2018, 54(88): 12467-12470; RSC Advances, 2016, 6(62): 57603-57625; Chemical Society Reviews, 2012, 41(4): 1415-1427.).

[0003] Currently, there are three main methods for constructing N-(substituted benzyl)aromatic amines. The first method is to use visible light or photocatalysts (such as eosin Y and ruthenium catalysts) to initiate single electron transfer (SET) to achieve C / C bond cleavage (ChemCatChem, 2016, 8(6): 1028-1032; Advanced Synthesis & Catalysis, 2021, 363(15): 3803-3811; Angewandte Chemie International Edition, 2015, 54(30): 8828-8832; RSC Advances, 2021, 11(31): 18966-18973.). The second method uses transition metals (such as Fe, Ir, Ni) or their salts as catalysts to activate CH and C / C bonds and promote coupling reactions (Chemical Communications, 2009, 47: 7372-7374; Nature Catalysis, 2021, 4(8): 703-710; Journal of the American Chemical Society, 2020, 142(49): 20594-20599.). The third method uses oxidants (such as DTBP, TBHP, O2) to promote oxidation reactions and combine coupling or cyclization to construct new skeletons (Organic Letters, 2021, 23(7): 2664-2669; The Journal of Organic Chemistry, 2024, 89(3): 1524-1533.). In recent years, researchers have successively developed various C / C bond breaking methods, such as transition metal catalytic systems, organic photocatalytic systems, and redox-mediated strategies. It is worth noting that these traditional methods have significant drawbacks in terms of environmental compatibility: metal catalyst residues are difficult to remove, and strong oxidizing / reducing reagents cause severe pollution, limiting their practical applications. To address this, this study developed a novel green C-C bond cleavage method based on visible light photocatalysis. Using the environmentally friendly photocatalyst 3CzEPAIPN, efficient conversion of Schiff bases was achieved in a reaction system composed of DIPEA and acetonitrile, successfully constructing N-(substituted benzyl)arylamine skeletons. This method innovatively employs a metal-free catalytic system, avoiding the use of strong oxidants, and exhibits good selectivity and atom economy under mild reaction conditions, providing a promising new strategy for C-C bond activation in the field of green synthesis. Summary of the Invention

[0004] The purpose of this invention is to overcome the limitations of current methods for synthesizing N-(substituted benzyl)aromatic amines and to develop a photocatalytic metal-free reduction coupling and C / C bond breaking reaction under visible light conditions using 3CzEPAIPN as a catalyst and DIPEA as a base for the rapid generation of N-(substituted benzyl)aromatic amines.

[0005] The invention involves a photocatalytic reaction conducted under a nitrogen atmosphere, using 3CzEPAIPN (3 mol%) as a catalyst, N,N-diisopropylethylamine (DIPEA, 3 equivalents) as a basic additive, and CH3CN as the reaction solvent. The reaction system is irradiated with a dual-wavelength 450-460 nm blue LED light source and allowed to react continuously at room temperature for 3-4 hours. This invention avoids the use of metal catalysts and toxic reagents. Furthermore, the reaction is simple to operate, operates under mild conditions, yields excellent separation, and has a wide range of applicable substrates.

[0006] The objective of this invention is achieved through the following technical solution.

[0007] A method for synthesizing N-(substituted benzyl)aromatic amine compounds under visible light conditions includes the following steps: In a glass reaction vessel, (E)-N,1-diarylmethylimine 1, 3CzEPAIPN, and N,N-diisopropylethylamine were added in proportion. CH3CN was used as solvent, and the mixture was magnetically stirred at room temperature under blue light irradiation for 3-4 h. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the N-(substituted benzyl)arylamine compound 2 was obtained by column chromatography separation and purification.

[0008] Furthermore, the chemical reaction equations for the reductive coupling and C / C bond cleavage of (E)-N,1-diarylmethylimine 1 are shown below:

[0009] In the formula, R 1 R 2 It is selected from one or more of phenyl, halogen atom, methyl, ethyl, p-methyl, tert-butyl, methoxy, tert-butyl, and benzyl; Furthermore, the additive is N,N-diisopropylethylamine.

[0010] Furthermore, the molar ratio of the additive to the (E)-N,1-diarylmethylimine derivative is 3:1.

[0011] Furthermore, the organic solvent is one or more of methanol, acetonitrile, tetrahydrofuran, DMSO, and 1,4-dioxane, with acetonitrile being the preferred solvent.

[0012] Furthermore, the reductive coupling reaction time of the (E)-N,1-diarylmethylimine is 3-4 h.

[0013] Further, the catalyst is one or more of 4-DPAIPN, 2,4,5,6-tetracarbazolium isophthalonitrile (4CzIPN), 2,4,5-tricarbazolium-6-(N-methylaniline) isophthalonitrile (3CzMPAIPN), and 3CzEPAIPN, preferably 3CzEPAIPN.

[0014] Furthermore, the molar ratio of the catalyst to the (E)-N,1-diarylmethylimine compound is 0.03:1.

[0015] Furthermore, the target product N-(substituted benzyl)arylamine is separated and purified by column chromatography. The eluent can be a mixed solvent of petroleum ether and ethyl acetate, with a volume ratio of ethyl acetate to petroleum ether between 1:3 and 10. Preferably, the developing solvent is petroleum ether:ethyl acetate = 5:1.

[0016] The principle of this invention is as follows: Under blue light irradiation, the photocatalyst 3CzEPAIPN is transformed into 3CzEPAIPN. * Then 3CzEPAIPN * A single-electron transfer with DIPEA yields 3CzEPAIPN. ·- Imine and 3CzEPAIPN ·- An α-amino radical anion is generated via a single-electron transfer mechanism, while 3CzEPAIPN completes its cycle back to the ground state. The α-amino radical anion extracts an H atom from the DIPEA species. + Then, through C-C reductive coupling, the intermediate 1,2-ethylenediamine is obtained. Under visible light, 1,2-ethylenediamine undergoes C-C bond cleavage to generate an α-amino radical anion, which is then released from... Extract one The final product N-(substituted benzyl)arylamine was obtained.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) This method innovatively adopts a metal-free catalytic system, avoids the use of strong oxidants, and exhibits good selectivity and atom economy under mild reaction conditions.

[0018] (2) This study developed a novel green C-C bond breaking method based on visible light photocatalysis. Using the environmentally friendly photocatalyst 3CzEPAIPN, the efficient conversion of Schiff base compounds was achieved in a reaction system composed of DIPEA and acetonitrile, and the N-(substituted benzyl)aromatic amine skeleton was successfully constructed. Attached Figure Description

[0019] Figure 1 , Figure 2These are the proton and carbon spectra of the target product obtained in Example 1; Figure 3 , Figure 4 These are the proton and carbon spectra of the target product obtained in Example 2; Figure 5 , Figure 6 These are the proton and carbon spectra of the target product obtained in Example 3; Figure 7 , Figure 8 These are the proton and carbon spectra of the target product obtained in Example 4; Detailed Implementation

[0020] The present invention will be further described below with specific examples, but the scope of protection and implementation of the present invention are not limited thereto.

[0021] Example 1

[0022] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-bromophenyl)-N-phenylmethylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-bromobenzyl)aniline was purified by silica gel column chromatography with a yield of 69%.

[0023] The proton and carbon spectra of the obtained target product are as follows: Figure 1 and Figure 2 As shown, the structural characterization data is as follows: 1 H NMR (500 MHz, Chloroform-d) δ 7.63 (d, J = 7.9 Hz, 1H), 7.47 (d, J= 7.9 Hz, 1H), 7.31 (t, J = 7.5 Hz, 1H), 7.24 (t, J = 7.8 Hz, 2H), 7.19 (t, J= 7.7 Hz, 1H), 6.79 (t, J = 7.3 Hz, 1H), 6.67 (d, J = 7.9 Hz, 2H), 4.46 (s,2H), 4.28 (s, 1H) ppm. 13 C { 1H}NMR (125 MHz, Chloroform-d) δ 147.4, 138.0, 132.5, 129.1,128.8, 128.4, 127.3, 123.0, 117.5, 112.6, 48.1 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 13 H 12 BrN 262.0226; found262.0229. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0024] Example 2

[0025] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-bromophenyl)-N-(4-bromophenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product 4-bromo-N-(2-bromobenzyl)aniline was purified by silica gel column chromatography with a yield of 57%.

[0026] The proton and carbon spectra of the obtained target product are as follows: Figure 3 and Figure 4 As shown, the structural characterization data is as follows: 1 H NMR (500 MHz, Chloroform-d) δ 7.61 (d, J = 7.9 Hz, 1H), 7.38 (d, J= 7.7 Hz, 1H), 7.28 (t, J = 8.4 Hz, 3H), 7.20 - 7.15 (m, 1H), 6.52 (s, 1H), 6.50 (s, 1H), 4.40 (s, 2H), 4.28 (s, 1H) ppm. 13 C { 1 H}NMR (125 MHz, Chloroform-d) δ 146.5, 137.5, 132.8, 131.9,129.0, 128.8, 127.5, 123.2, 114.4, 109.3, 48.3 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 13 H 11 Br2N 339.9331; found 339.9334. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0027] Example 3

[0028] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-bromophenyl)-N-(o-tolyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-bromobenzyl)-2-methylaniline was purified by silica gel column chromatography with a yield of 68%.

[0029] The proton and carbon spectra of the obtained target product are as follows: Figure 5 and Figure 6 As shown, the structural characterization data is as follows: 1 H NMR (500 MHz, DMSO-d6) δ 7.48 - 7.40 (m, 1H), 7.34 - 7.29 (m, 1H), 7.28 - 7.22 (m, 2H), 6.99 (d, J = 7.2 Hz, 1H), 6.88 (d, J = 7.1 Hz, 1H), 6.48(t, J = 7.3 Hz, 1H), 6.20 (d, J = 8.1 Hz, 1H), 5.70 (t, J = 6.1 Hz, 1H), 4.40(d, J = 6.0 Hz, 2H), 2.18 (s, 3H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 145.7, 137.1, 132.0, 129.9, 129.2,128.4, 128.3, 127.1, 126.7, 121.8, 116.0, 109.2, 44.1, 17.8 ppm. HRMS (ESI-TOF) m / z: [M+H] +calcd for C 14 H 14 BrN 276.0382; found276.0374. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0030] Example 4

[0031] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-bromophenyl)-N-(4-ethylphenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-bromobenzyl)-4-ethylaniline was purified by silica gel column chromatography with a yield of 73%.

[0032] The proton and carbon spectra of the obtained target product are as follows: Figure 7 and Figure 8 As shown, the structural characterization data is as follows: 1 H NMR (500 MHz, Chloroform-d) δ 7.83 (dt, J = 17.5, 8.2 Hz, 1H), 7.65 (dt, J = 15.6, 7.6 Hz, 1H), 7.46 (dq, J = 14.3, 7.4 Hz, 1H), 7.39 - 7.26(m, 3H), 6.80 (dt, J = 17.2, 8.3 Hz, 2H), 4.67 - 4.54 (m, 2H), 4.26 (s, 1H), 2.91 - 2.76 (m, 2H), 1.59 - 1.44 (m, 3H) ppm. 13 C { 1 H}NMR (125 MHz, Chloroform-d) δ 145.5, 138.3, 133.2, 132.5,128.9, 128.4, 127.3, 123.0, 112.8, 48.4, 27.8, 15.9 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 15 H 16BrN 290.0539; found 290.0546. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0033] Example 5

[0034] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-bromophenyl)-N-(2,5-dimethylphenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-bromobenzyl)-2,5-dimethylaniline was obtained by silica gel column chromatography with a yield of 67%.

[0035] The structural characterization data of the obtained target product are shown below: 1 H NMR (500 MHz, DMSO-d6) δ 7.60 (d, J = 7.9 Hz, 1H), 7.35 (d, J = 7.8Hz, 1H), 7.31 - 7.27 (m, 1H), 7.16 (t, J = 6.7 Hz, 1H), 6.88 (d, J = 7.4 Hz,1H), 6.34 (d, J = 5.8 Hz, 1H), 6.11 (s, 1H), 5.61 (t, J = 6.1 Hz, 1H), 4.40(d, J = 5.8 Hz, 2H), 2.17 (s, 3H), 2.08 (s, 3H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 145.7, 138.7, 135.5, 132.3, 129.8,128.6, 128.5, 127.6, 122.4, 118.8, 116.8, 110.0, 46.8, 21.2, 17.4ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 15 H 17 BrN 290.0539; found290.0539. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0036] Example 6

[0037] A quartz reaction tube was prepared for use. Weighed (E)-N-([1,1'-biphenyl]-4-yl)-1-(2-bromophenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere with blue light irradiation at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-bromobenzyl)-[1,1'-biphenyl]-4-amine was purified by silica gel column chromatography with a yield of 67%.

[0038] The structural characterization data of the obtained target product are shown below: 1 H NMR (500 MHz, DMSO-d6) δ 7.65 (dd, J = 8.0, 1.2 Hz, 1H), 7.58 -7.51 (m, 2H), 7.45 - 7.40 (m, 3H), 7.39 - 7.33 (m, 3H), 7.27 - 7.19 (m, 2H), 6.67 - 6.61 (m, 2H), 6.52 (t, J = 6.1 Hz, 1H), 4.36 (d, J = 6.0 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 147.8, 140.5, 138.3, 132.4, 128.9,128.8, 128.7, 127.9, 127.7, 127.2, 125.7, 125.4, 122.6, 112.5, 46.7ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 19 H 16 BrN 338.0539; found338.0548. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0039] Example 7

[0040] A quartz reaction tube was prepared for use. Weighed (E)-1-(4-bromophenyl)-N-(4-tert-butylphenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(4-bromobenzyl)-4-tert-butylaniline was purified by silica gel column chromatography with a yield of 47%.

[0041] The structural characterization data of the obtained target product are shown below: 1 H NMR (500 MHz, DMSO-d6) δ 7.48 (d, J = 8.4 Hz, 2H), 7.30 (d, J = 8.1Hz, 2H), 7.05 (d, J = 8.5 Hz, 2H), 6.47 (d, J = 8.5 Hz, 2H), 6.12 (t, J = 6.2Hz, 1H), 4.21 (d, J = 6.1 Hz, 2H), 1.18 (s, 9H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 145.9, 140.2, 138.0, 131.1, 129.3,125.4, 119.4, 112.0, 46.0, 33.4, 31.4 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 17 H 20 BrN 318.0852; found318.0853. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0042] Example 8

[0043] A quartz reaction tube was prepared for use. Weighed (E)-N,1-bis(4-bromophenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the crude product 4-bromo-N-(4-bromobenzyl)aniline was purified by silica gel column chromatography with a yield of 51%.

[0044] The structural characterization data of the obtained target product are shown below: 1 H NMR (500 MHz, DMSO-d6) δ 7.49 (d, J = 8.4 Hz, 2H), 7.28 (d, J = 8.1Hz, 2H), 7.17 (d, J = 9.1 Hz, 2H), 6.56 - 6.51 (m, 2H), 6.51 (s, 1H), 4.23(d, J = 6.1 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 147.6, 139.3, 131.4, 131.2, 129.3,119.7, 114.2, 106.6, 45.6 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 13 H 11 Br2N 339.9331; found 339.9329. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0045] Example 9

[0046] A quartz reaction tube was prepared for use. Weighed (E)-N-(4-bromophenyl)-1-phenylmethylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-benzyl-4-bromoaniline was purified by silica gel column chromatography with a yield of 38%.

[0047] The structural characterization data of the obtained target product are shown below: 1 H NMR (500 MHz, DMSO-d6) δ 7.32 (d, J = 6.8 Hz, 4H), 7.23 (d, J = 6.5Hz, 1H), 7.16 (d, J = 8.7 Hz, 2H), 6.52 (d, J = 8.7 Hz, 2H), 6.48 (d, J = 5.9Hz, 1H), 4.24 (d, J = 6.0 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 147.9, 139.8, 131.3, 128.3, 127.2,126.7, 114.2, 106.3, 46.3 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 13 H 12 BrN 262.0226; found262.0230. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0048] Example 10

[0049] A quartz reaction tube was prepared for use. Weighed (E)-N-([1,1'-biphenyl]-4-yl)-1-phenylmethylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-benzyl-[1,1'-biphenyl]-4-amine was purified by silica gel column chromatography with a yield of 69%.

[0050] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.52 (d, J = 7.6 Hz, 2H), 7.40 - 7.31 (m,8H), 7.22 (dt, J = 14.3, 7.2 Hz, 2H), 6.66 (d, J = 8.3 Hz, 2H), 6.48 (t, J =6.1 Hz, 1H), 4.31 (d, J = 6.1 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 148.7, 141.0, 140.7, 129.2, 128.8, 128.0, 127.6, 127.1, 126.2, 125.9, 113.1, 46.8 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 19 H 17 N 260.1434; found 260.1439. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0051] Example 11

[0052] A quartz reaction tube was prepared for use. Weighed (E)-N-(4-bromophenyl)-1-(4-methoxyphenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product 4-bromo-N-(4-methoxybenzyl)aniline was purified by silica gel column chromatography with a yield of 51%.

[0053] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.25 (d, J = 8.5 Hz, 2H), 7.16 (d, J = 8.8Hz, 2H), 6.88 (d, J = 8.7 Hz, 2H), 6.52 (d, J = 8.8 Hz, 2H), 6.41 (d, J = 6.1Hz, 1H), 4.15 (s, 2H), 3.71 (s, 3H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 158.1, 147.9, 131.4, 131.3, 128.4,114.2, 113.7, 106.3, 55.0, 45.8 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 14 H 14 BrNO 292.0332; found292.0330. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0054] Example 12

[0055] A quartz reaction tube was prepared for use. Weighed (E)-N-(4-bromophenyl)-1-(p-tolyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the crude product 4-bromo-N-(4-methylbenzyl)aniline was purified by silica gel column chromatography with a yield of 42%.

[0056] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.23 (d, J = 8.1 Hz, 2H), 7.17 (d, J = 8.6Hz, 2H), 7.12 (d, J = 7.7 Hz, 2H), 6.53 (s, 2H), 6.45 (t, J = 6.1 Hz, 1H), 4.20 (d, J = 5.9 Hz, 2H), 2.27 (s, 3H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 147.9, 136.6, 135.7, 131.3, 128.9,127.1, 114.2, 106.3, 46.1, 20.7 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 14 H 14 BrN 276.0382; found276.0377. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0057] Example 13

[0058] A quartz reaction tube was prepared for use. Weighed (E)-N-([1,1'-biphenyl]-4-yl)-1-(2-chlorophenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere with blue light irradiation at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-chlorobenzyl)-[1,1'-biphenyl]-4-amine was purified by silica gel column chromatography with a yield of 63%.

[0059] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.52 (d, J = 7.6 Hz, 2H), 7.46 (d, J = 6.8Hz, 1H), 7.40 (d, J = 8.4 Hz, 3H), 7.36 (d, J = 7.2 Hz, 2H), 7.29 (s, 2H), 7.21 (d, J = 7.6 Hz, 1H), 6.63 (s, 2H), 6.53 (s, 1H), 4.39 (s, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 147.9, 140.5, 136.9, 132.3, 129.3,128.8, 128.7, 128.5, 127.9, 127.3, 127.2, 125.8, 125.5, 112.5, 44.1 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 19 H 16 ClN 294.1044; found 294.1048. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0060] Example 14

[0061] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-chlorophenyl)-N-(naphth-2-yl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours, monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-chlorobenzyl)naphth-2-amine was purified by silica gel column chromatography with a yield of 68%.

[0062] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.63 (dd, J = 8.5, 5.2 Hz, 2H), 7.51 -7.47 (m, 2H), 7.45 (dt, J = 7.4, 3.8 Hz, 1H), 7.29 - 7.25 (m, 3H), 7.12 -7.07 (m, 2H), 6.62 (d, J = 8.9 Hz, 2H), 4.45 (d, J = 5.8 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 146.2, 136.7, 135.0, 132.5, 129.3,128.9, 128.5, 128.5, 127.4, 127.2, 126.6, 126.1, 125.5, 121.2, 118.1, 102.6,44.2 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 17 H 14 ClN 268.0888; found268.0900. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0063] Example 15

[0064] A quartz reaction tube was prepared for use. Weighed (E)-1-(2-chlorophenyl)-N-(naphth-1-yl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(2-chlorobenzyl)naphth-1-amine was purified by silica gel column chromatography with a yield of 62%.

[0065] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 8.35 - 8.30 (m, 1H), 7.79 - 7.74 (m, 1H), 7.49 - 7.44 (m, 3H), 7.39 (dd, J = 7.3, 2.1 Hz, 1H), 7.28 - 7.20 (m, 2H), 7.18 (t, J = 7.9 Hz, 1H), 7.11 (d, J = 8.1 Hz, 1H), 7.05 (t, J = 5.9 Hz, 1H), 6.26 (d, J = 7.5 Hz, 1H), 4.60 (d, J = 5.7 Hz, 2H) ppm. 13 C { 1 H} NMR(125 MHz, DMSO-d6) δ 143.4, 136.6, 134.1, 132.2, 129.2,128.3, 128.2, 128.1, 127.1, 126.7, 125.7, 124.2, 123.0, 121.6, 115.9, 103.3,44.3 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 17 H 14 ClN 268.0888; found268.0891. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0066] Example 16

[0067] A quartz reaction tube was prepared for use. Weighed (E)-1-(4-chlorophenyl)-N-(naphth-1-yl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(4-chlorobenzyl)naphth-1-amine was purified by silica gel column chromatography with a yield of 53%.

[0068] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.65 (t, J = 8.2 Hz, 2H), 7.52 (d, J = 8.2Hz, 1H), 7.45 (d, J = 8.5 Hz, 2H), 7.40 (d, J = 8.5 Hz, 2H), 7.29 (t, J = 7.6Hz, 1H), 7.14 - 7.10 (m, 2H), 6.72 (d, J = 2.4 Hz, 1H), 6.65 (t, J = 6.1 Hz,1H), 4.40 (d, J = 6.0 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 146.3, 139.0, 135.0, 131.3, 129.1,128.5, 128.3, 127.5, 126.6, 126.0, 125.5, 121.2, 118.3, 103.0, 45.8ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 17 H 14 ClN 268.0888; found268.0903. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0069] Example 17

[0070] A quartz reaction tube was prepared for use. Weighed (E)-1-(4-chlorophenyl)-N-(naphth-2-yl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the final product N-(4-chlorobenzyl)naphth-2-amine was purified by silica gel column chromatography with a yield of 73%.

[0071] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 8.26 (s, 1H), 7.75 (s, 1H), 7.47 - 7.40(m, 4H), 7.35 (d, J = 8.1 Hz, 2H), 7.17 (t, J = 7.9 Hz, 1H), 7.08 (d, J = 8.2Hz, 1H), 7.03 (t, J = 6.0 Hz, 1H), 6.32 (d, J = 7.5 Hz, 1H), 4.50 (d, J = 5.8Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 143.4, 139.2, 134.1, 131.0, 128.7,128.2, 128.0, 126.7, 125.7, 124.1, 123.1, 121.6, 115.6, 103.7, 45.7 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 17 H 14 ClN 268.0888; found268.0901. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0072] Example 18

[0073] A quartz reaction tube was prepared for use. Weighed (E)-N-(4-bromophenyl)-1-(4-chlorophenyl)methylimine (0.2 mmol), N,N-diisopropylethylamine (0.6 mmol), 3CzEPAIPN (0.006 mmol), and acetonitrile (4 mL) were added sequentially. The reaction was carried out under a nitrogen atmosphere and irradiated with blue light at room temperature for 3-4 hours. The reaction was monitored by TCL. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the crude product 4-bromo-N-(4-chlorobenzyl)aniline was purified by silica gel column chromatography with a yield of 62%.

[0074] The structural characterization data of the obtained target product are shown below: 1H NMR (500 MHz, DMSO-d6) δ 7.37 (d, J = 8.5 Hz, 2H), 7.34 (d, J = 8.7Hz, 2H), 7.16 (d, J = 8.9 Hz, 2H), 6.54 (t, J = 6.1 Hz, 1H), 6.52 - 6.48 (m,2H), 4.24 (d, J = 5.8 Hz, 2H) ppm. 13 C { 1 H}NMR (125 MHz, DMSO-d6) δ 147.6, 138.9, 131.4, 131.2, 129.0,128.3, 114.2, 106.5, 45.5 ppm. HRMS (ESI-TOF) m / z: [M+H] + calcd for C 13 H 11 BrClN 295.9836; found295.9833. Based on the above characterization data, the structure of the target compound is inferred as follows:

[0075] The above embodiments are some examples of the method of the present invention, but they do not limit the specific implementation of the present invention. Any substitution of substituents, changes in the basic skeleton, or simplification of conditions made without departing from the spirit and principle of the present invention should be classified as equivalent substitution methods and are included within the protection scope of the present invention.

Claims

1. A method for synthesizing N-(substituted benzyl)aromatic amine compounds under visible light conditions, characterized in that, It includes the following steps: In a glass reaction vessel, (E)-N,1-diarylmethylimine 1, 3CzEPAIPN, and N,N-diisopropylethylamine were added in proportion. CH3CN was used as solvent, and the mixture was magnetically stirred at room temperature under blue light irradiation for 3-4 h. After the reaction was completed, the crude product was obtained by rotary evaporation under reduced pressure. Finally, the N-(substituted benzyl)arylamine compound 2 was obtained by column chromatography separation and purification.

2. The synthesis method according to claim 1, characterized in that, The chemical reaction equations for the reductive coupling and C / C bond cleavage of (E)-N,1-diarylmethylimine 1 are shown below: In the formula, R 1 R 2 It is selected from one or more of phenyl, halogen atom, methyl, ethyl, p-methyl, tert-butyl, methoxy, and tert-butyl.

3. The preparation method according to claim 1 or 2, characterized in that, The additive is N,N-diisopropylethylamine; the molar ratio of the additive to (E)-N,1-diarylmethylimine derivatives is 3:

1.

4. The preparation method according to claim 1 or 2, characterized in that, The organic solvent is one or more of methanol, acetonitrile, tetrahydrofuran, DMSO, and 1,4-dioxane, with acetonitrile being preferred.

5. The preparation method according to claim 1 or 2, characterized in that, The catalyst is one or more of 4-DPAIPN, 2,4,5,6-tetracarbazole isophthalonitrile (4CzIPN), 2,4,5-tricarbazole-6-(N-methylaniline) isophthalonitrile (3CzMPAIPN), and 3CzEPAIPN, preferably 3CzEPAIPN; the molar ratio of the catalyst to the (E)-N,1-diarylmethylimine compound is 0.03:

1.

6. The preparation method according to claim 1 or 2, characterized in that, The reductive coupling and C / C bond cleavage reaction of the (E)-N,1-diarylmethylimine takes 3-4 h.

7. The preparation method according to claim 1 or 2, characterized in that, The target product, N-(substituted benzyl)aromatic amine derivative, was purified by column chromatography. The eluent was a mixture of petroleum ether and ethyl acetate in a volume ratio of 10:1 to 3:1.

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