Method for synthesizing N-(phenanthridine-6-ylmethyl) benzamide compound through visible light catalysis

Abstract

The invention discloses a method for synthesizing an N-(phenanthridine-6-yl methyl) benzamide compound through visible light catalysis, which comprises the following steps: taking 2-aryl phenyl isocyanide and hydroxamic acid ester as raw materials, and cyclizing in a solvent under the irradiation of visible light with the wavelength of 450-455nm to generate a phenanthridine derivative. On the basis of the method, a series of N-(phenanthridine-6-yl methyl) benzamide compounds are obtained by using different substituted 2-aryl phenyl isocyanide and hydroxamic acid ester. Compared with a traditional method for synthesizing the phenanthridine derivative, the method has the advantages that the condition is mild, high temperature and high pressure are not needed, an additional oxidant is not needed, and a unique method is provided for synthesizing the phenanthridine derivative; the method has the advantages of wide substrate application range, simple operation steps and high product yield.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemical synthesis, and in particular to a method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds catalyzed by visible light. Background Art

[0002] As the most active component in organic synthesis, nitrogen-containing heterocycles (N-heterocycles) not only play an important role in various bioactive substrates, drugs, natural products and organic materials, but are also recognized as key intermediates in synthetic chemistry. Among them, phenanthridine is one of the most important and attractive N-heterocycles, which is widely present in many natural products, drugs and functionalized polycyclic heterocycles. In view of the great potential of phenanthridine in drug and material chemistry, the exploration of efficient and selective preparation methods of phenanthridine derivatives has always attracted much attention. Among the various synthetic methods reported for phenanthridine compounds, the intramolecular cyclization of ortho-substituted diaryl compounds is the main synthetic method. At present, the intramolecular cyclization methods for synthesizing phenanthridine derivatives mainly include: free radical cyclization method, benzylene method, multi-component one-pot cascade method, microwave-promoted method and transition metal catalysis method. However, there are still certain limitations in these methods: such as the difficulty in obtaining reaction raw materials, harsh reaction conditions, more steps, low yield, and lack of universal applicability.

[0003] Therefore, it is of great significance to develop a new method for synthesizing phenanthridine derivatives under efficient, simple and mild conditions. Summary of the invention

[0004] The present invention aims to provide a method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis, wherein the method uses 2-arylphenylisocyanate and hydroxamate as raw materials, and synthesizes N-(phenanthridin-6-ylmethyl)benzamide compounds by a visible light-mediated free radical tandem cyclization reaction. The reaction conditions are mild, the operation is simple, the substrate has a wide range of application, and the atomic utilization rate is high, and the method has broad application prospects.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The present invention provides a method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis. The method comprises: using 2-arylphenylisocyanate and hydroxamate as raw materials, carrying out a photocatalytic reaction under the conditions of a photosensitizer, a base and a solvent, visible light irradiation and argon protection, to synthesize N-(phenanthridin-6-ylmethyl)benzamide compounds, and the chemical reaction formula is:

[0007]

[0008] in:

[0009] R1 is selected from hydrogen, methoxy, methyl, tert-butyl;

[0010] R2 is selected from hydrogen, halogen, methoxy, methyl, tert-butyl, n-butyl, thiomethyl or phenoxy;

[0011] R3 is selected from hydrogen, halogen, methoxy, tert-butyl, methyl, cyclohexane, cyclopentane.

[0012] Furthermore, the solvent is N,N-dimethylethylamine. The volume of the solvent is preferably 1.0 mL.

[0013] Furthermore, the base is triethylenediamine.

[0014] Furthermore, the photosensitizer is bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt.

[0015] Further, the amount of the photosensitizer is 0.5-1.0 mol% of the molar amount of 2-arylphenylisocyanate. Preferably, the molar amount of the photosensitizer is 0.5 mol% of the molar amount of 2-arylphenylisocyanate.

[0016] Further, the molar ratio of the 2-arylphenyl isocyanate:hydroxamate:base is 1:(1.5-2.0):(1.5-3.0). Preferably, the molar amount of the base is 3 times the molar amount of the 2-arylphenyl isocyanate.

[0017] Furthermore, the reaction concentration of the 2-arylphenyl isocyanate is 0.05-0.2 mol / L.

[0018] Furthermore, the wavelength of the visible light is 450-455nm, and the power is 12W.

[0019] Furthermore, the photocatalytic reaction time is 24 hours.

[0020] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0021] The present invention is the first to report the use of visible light catalysis to synthesize N-(phenanthridin-6-ylmethyl)benzamide compounds, breaking through the barrier limitations of traditional reactions. Compared with traditional methods, the present invention has the following significant advantages:

[0022] (1) Mild conditions: room temperature reaction, only 450-455nm visible light is required, no high temperature, high pressure or additional oxidants are required.

[0023] (2) Green and efficient: high atom utilization, product yield as high as 63%-89%, and few side reactions.

[0024] (3) Substrate universality: R1, R2, and R3 can include a variety of substituents such as hydrogen, halogen, methoxy, and phenoxy, with strong adaptability. A total of 18 target compounds were synthesized, covering a variety of substituent combinations, verifying the universality of the method.

[0025] (4) Simple operation: only the raw materials, photosensitizer, base and solvent need to be mixed, and column chromatography purification can be performed directly after the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 is the H NMR spectrum of the compound of the present invention.

[0028] Figure 2 is the NMR carbon spectrum of the compound of the present invention.

[0029] Figure 3 It is the reaction equation involved in the present invention.

[0030] Figure 4 The figure is a reaction mechanism diagram that may be involved in the reaction of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0032] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0033] To solve the technical problem of the present invention, the overall idea of ​​the present invention is as follows:

[0034] Hydrogen atom transfer (HAT) processes provide an important strategy for selective CH functionalization. Recently, 1,5-hydrogen transfer from N- or O-centered radicals has been well developed and widely used to build complex molecules via photoredox catalysis due to the low barrier and stable six-membered chair transition state. In contrast, 1,2-hydrogen transfer processes are uncommon due to the high barrier and constrained natural three-center transition state. Therefore, product formation via a net 1,2-HAT process remains a major challenge in modern organic synthesis.

[0035] According to a typical embodiment of the present invention, a method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis is provided, the method comprising: using 2-arylphenylisocyanate and isohydroxamate as raw materials, carrying out a photocatalytic reaction under the conditions of a photosensitizer, a base and a solvent and visible light irradiation and argon protection to synthesize N-(phenanthridin-6-ylmethyl)benzamide compounds.

[0036] The reaction mechanism involved in this reaction (such as Figure 4 shown) is:

[0037] Under visible light irradiation, the photocatalyst [Ir(III)] forms an excited state [Ir(III)]*. Subsequently, [Ir(III)]* and hydroxamate 2a undergo a single electron transfer (SET) process to produce an amide radical A, a carboxylate anion (ArCOO-), and [Ir(IV)]. Subsequently, through an intramolecular 1,2-hydrogen atom transfer (1,2-HAT) process, the amide radical A is converted into a more stable carbon-centered radical B, which is captured by the ground state 2-arylphenylisocyanate 1a to generate an imine radical C, which then undergoes intramolecular cyclization to form intermediate D. Intermediate D then interacts with [Ir(IV)] and undergoes a second SET process to form a cationic intermediate E and [Ir(III)]. Finally, intermediate E undergoes deprotonation to generate the target product 3a.

[0038] By nuclear magnetic resonance spectroscopy ( 1 H NMR), carbon spectrum ( 13 C NMR) and high-resolution mass spectrometry confirmed the structure of N-(phenanthridin-6-ylmethyl)benzamide compounds, as shown in the attached Figure 1 , Attachment Figure 2 The nuclear magnetic resonance images were measured using a Varian INOVA-400 nuclear magnetic resonance instrument, with tetramethylsilane (TMS) as the internal standard (δ0 ppm) and deuterated chloroform as the solvent; the high-resolution mass spectra were measured using an Agilent 1946B mass spectrometer. Figure 1 Nuclear magnetic resonance (NMR): clearly shows the chemical shifts of the phenanthridine ring, amide group and substituents. Figure 2High-resolution mass spectrometry (HRMS): The molecular ion peak matches the theoretical value (e.g. [M+H] + The peak is 313.1335).

[0039] The N-(phenanthridin-6-ylmethyl)benzamide compounds prepared by the present invention have great application prospects:

[0040] (1) Can be used as drug intermediates: Phenanthridine compounds are the core structural units of anti-tumor drugs (such as vorinostat) and antiviral drugs (such as atazanavir).

[0041] (2) Can be used as functional materials: used to prepare optoelectronic materials (such as OLED devices) and catalysts (such as MnO2 nanoparticles).

[0042] (3) Industrial potential: Mild conditions and high yields are suitable for large-scale production, reducing energy consumption and costs.

[0043] The following will describe in detail a method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds catalyzed by visible light in the present application in combination with embodiments, comparative examples and experimental data.

[0044] Example 1: Synthesis of Compound 3a

[0045]

[0046] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-1,1'-biphenyl 1a (17.9 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0047] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 23.7 mg of the product as a white solid with a yield of 76% and a melting point of 135-136°C; 1 H NMR (400MHz, Chloroform-d) δ8.81–8.45 (m, 3H), 8.30–7.49 (m, 11H), 5.29 (d, J = 4.2Hz, 2H). 13C NMR (100 MHz, Chloroform-d) δ 167.4, 154.4, 142.5, 134.7, 132.9, 131.7, 131.3, 129.6, 129.0, 128.8, 128.1, 127.34, 127.29, 124.9, 124.2, 122.7, 122.3, 42.7. HRMS (ESI) m / z: Calculated value C 21 H 17 N2O[M+H] + 313.1335, measured value: 313.1333.

[0048] Example 2: Synthesis of Compound 3b

[0049]

[0050] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-4-methyl-1,1'-biphenyl 1b (19.3 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0051] (2) After the reaction was completed, silica gel column chromatography was used to separate and purify the product to obtain 28.1 mg of a white solid with a yield of 86% and a melting point of 104-105°C; 1 H NMR(400MHz,Chloroform-d)δ8.67(t,J=3.9Hz,1H),8.56(dd,J=8.3,1.1Hz,1H),8.40(d,J=8.4Hz,1H),8.17(dd,J=8.3,1.2Hz,1H),8.08–8.00(m,2 H),7.93(d,J=1.8Hz,1H),7.86–7.81(m,1H),7.71–7.65(m,1H),7.60–7.5 1(m,3H),7.48(dd,J=8.3,1.8Hz,1H),5.23(d,J=3.9Hz,2H),2.60(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 154.2, 142.6, 139.2, 134.7, 132.9, 131.6, 131.2, 129.1, 128.9, 128.8, 127.5, 127.3, 124.7, 123.8, 122.5, 122.1, 121.8, 42.7, 21.7. HRMS (ESI) m / z: calcd. 22 H 19 N2O[M+H] + 327.1492, measured value: 327.1496.

[0052] Example 3: Synthesis of Compound 3c

[0053]

[0054] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-5-methoxy-1,1'-biphenyl 1c (20.9 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0055] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 24.6 mg of the product as a yellow solid with a yield of 75% and a melting point of 209-210°C; 1 H NMR(400MHz,Chloroform-d)δ8.64(t,J=4.0Hz,1H),8.46(dd,J=8.3,1.4Hz,1H),8.15–8.11(m,2H),8.06–8.00(m,2H),7.93(d,J=2 .5Hz,1H),7.75–7.71(m,1H),7.66–7.61(m,1H),7.58–7.49(m,3H),7.32(dd,J=9.0,2.5Hz,1H),5.22(d,J=3.9Hz,2H),4.04(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 161.8, 153.8, 135.1, 134.8, 131.6, 129.7, 129.1, 128.8, 127.3, 126.7, 124.0, 122.3, 119.1, 118.0, 103.6, 55.7, 42.7. HRMS (ESI) m / z: calculated value [M+H] + C 22 H 19 N2O2 343.1441, measured value: 343.1443.

[0056] Example 4: Synthesis of Compound 3d

[0057]

[0058] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-4-tert-butyl-1,1'-biphenyl 1d (23.5 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0059] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 32.8 mg of the product as a white solid with a yield of 89% and a melting point of 107-109°C; 1 H NMR(400MHz,Chloroform-d)δ8.58(dd,J=51.3,8.5Hz,3H),8.27(d,J=8.3Hz,1H),8.19–8.11(m,1H),8.07 –7.98(m,2H),7.94–7.86(m,1H),7.80–7.69(m,2H),7.60–7.51(m,3H),5.33(d,J=3.9Hz,2H),1.50(s,9H). 13C NMR (100 MHz, Chloroform-d) δ 167.5, 154.4, 152.5, 142.7, 134.9, 132.9, 131.6, 131.2, 128.8, 127.6, 127.4, 125.5, 124.9, 124.0, 122.6, 122.0, 121.8, 42.9, 35.1, 31.5. HRMS (ESI) m / z: calcd. 25 H 25 N2O[M+H] + 369.1961, measured value: 369.1963.

[0060] Example 5: Synthesis of Compound 3e

[0061]

[0062] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-6-methyl-1,1'-biphenyl 1e (19.3 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0063] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 21.5 mg of the product as a yellow solid with a yield of 66% and a melting point of 212-213°C; 1 H NMR(400MHz,Chloroform-d)δ8.86(d,J=8.6Hz,1H),8.68(t,J=3.6Hz,1H),8.27–8.15(m,1H),8.10–7.96 (m,3H),7.87–7.80(m,1H),7.72(t,J=7.6Hz,1H),7.63–7.45(m,5H),5.21(d,J=3.9Hz,2H),3.07(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 153.6, 143.9, 135.3, 134.7, 134.1, 131.6, 131.5, 130.4, 128.7, 128.6, 128.1, 127.3, 127.2, 127.1, 125.0, 124.7, 123.7, 42.6, 26.9. HRMS (ESI) m / z: calcd. 22 H 19 N2O[M+H] + 327.1492, measured value: 327.1491.

[0064] Example 6: Synthesis of Compound 3f

[0065]

[0066] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-2'-methyl-1,1'-biphenyl 1f (19.3 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0067] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 21.2 mg of the product as a yellow solid with a yield of 65% and a melting point of 93-95°C; 1 H NMR(400MHz,Chloroform-d)δ8.85–8.80(m,1H),8.76(s,1H),8.26–8.14(m,2H),8.07– 8.03(m,2H),7.79–7.65(m,4H),7.57–7.51(m,3H),5.28(d,J=3.9Hz,2H),3.14(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.4, 154.7, 136.1, 135.6, 134.7, 132.4, 131.6, 129.9, 128.8, 128.3, 127.5, 127.3, 126.9, 126.6, 125.64, 125.62, 123.3, 43.0, 27.1. HRMS (ESI) m / z: calcd. 22 H 19 N2O[M+H] + 327.1492, measured value: 327.1490.

[0068] Example 7: Synthesis of Compound 3g

[0069]

[0070] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-4'-methoxy-1,1'-biphenyl 1 g (20.9 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0071] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 25.3 mg of the product as a white solid with a yield of 74% and a melting point of 192-193°C; 1 H NMR(400MHz,Chloroform-d)δ8.61(t,J=3.9Hz,1H),8.46–8.35(m,2H),8.09–7.98(m,3H),7.66–7 .50(m,5H),7.42(dd,J=9.0,2.6Hz,1H),7.33(d,J=2.6Hz,1H),5.10(d,J=3.9Hz,2H),3.95(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 159.1, 153.2, 141.6, 134.6, 131.6, 129.5, 128.7, 127.9, 127.3, 127.2, 127.1, 125.3, 124.22, 124.16, 122.2, 121.7, 104.1, 55.9, 42.7. HRMS (ESI) m / z: calcd. 22 H 19 N2O2[M+H] + 343.1441, measured value: 343.1445

[0072] Example 8: Synthesis of Compound 3h

[0073]

[0074] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 4'-n-butyl-2-isocyano-1,1'-biphenyl 1h (23.5 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0075] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 27.3 mg of the product as a white solid with a yield of 74% and a melting point of 159-160°C; 1 H NMR(400MHz,Chloroform-d)δ8.70(t,J=3.9Hz,1H),8.55–8.46(m,2H),8.12(dd,J=8.1,1.4Hz,1H),8.08–8.01(m,2H),7.96(d,J=1.7Hz,1H),7.73–7.67( m,2H),7.66–7.61(m,1H),7.59–7.50(m,3H),5.24(d,J=3.8Hz,2H),2.86(t,J =7.8Hz,2H),1.78–1.68(m,2H),1.43(q,J=7.4Hz,2H),0.98(t,J=7.3Hz,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.4, 154.0, 143.1, 142.3, 134.8, 132.3, 131.6, 130.9, 129.6, 128.8, 128.4, 127.3, 127.1, 124.28, 124.26, 123.7, 122.6, 122.1, 42.8, 36.0, 33.8, 22.5, 14.1. HRMS (ESI) m / z: calcd. 25 H 25 N2O[M+H] + 369.1961, measured value: 369.1958.

[0076] Example 9: Synthesis of Compound 3i

[0077]

[0078] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 4'-tert-butyl-2-isocyano-1,1'-biphenyl 1i (23.5 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0079] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 27.6 mg of the product as a white solid with a yield of 75% and a melting point of 194-195°C; 1 H NMR(400MHz,Chloroform-d)δ8.73(t,J=4.1Hz,1H),8.57(dd,J=18.5,8.4Hz,2H),8.20–8.14(m,2H),8.05(dd,J=7.5,1. 9Hz, 2H), 7.98 (dd, J=8.7, 2.0Hz, 1H), 7.75–7.64 (m, 2H), 7.55 (q, J=7.1, 6.5Hz, 3H), 5.33 (d, J=3.9Hz, 2H), 1.49 (s, 9H). 13C NMR (100 MHz, Chloroform-d) δ 167.4, 154.5, 151.4, 142.3, 134.9, 131.6, 130.8, 129.7, 129.5, 128.8, 128.6, 127.4, 127.2, 124.21, 124.18, 122.6, 122.2, 120.4, 42.7, 35.4, 31.5. HRMS (ESI) m / z: calcd. 25 H 25 N2O[M+H] + 369.1961, measured value: 369.1960.

[0080] Example 10: Synthesis of Compound 3j

[0081]

[0082] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-4'-phenoxy-1,1'-biphenyl 1j (27.1 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0083] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 29.1 mg of the product as a white solid with a yield of 72% and a melting point of 103-104°C; 1 H NMR(400MHz,Chloroform-d)δ8.66–8.56(m,2H),8.47(dd,J=8.2,1.6Hz,1H),8.14(dd,J=8.1,1.5Hz,1H),8.04–7.98(m,2 H),7.73–7.64(m,3H),7.61–7.50(m,4H),7.45–7.38(m,2H),7.24–7.19(m,1H),7.15–7.07(m,2H),5.09(d,J=3.8Hz,2H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 157.2, 156.5, 153.5, 142.0, 134.7, 131.6, 130.3, 129.6, 128.7, 128.6, 128.4, 127.4, 127.3, 125.5, 124.8, 124.5, 124.0, 123.7, 122.0, 119.4, 111.8, 42.6. HRMS (ESI) m / z: calcd. 27 H 21 N2O2[M+H] + 405.1598, measured value: 405.1596.

[0084] Example 11: Synthesis of Compound 3k

[0085]

[0086] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-4'-phenoxy-1,1'-biphenyl 1k (22.5 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0087] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 25.4 mg of the product as a white solid with a yield of 71% and a melting point of 221-223°C; 1 H NMR(400MHz,Chloroform-d)δ8.59(t,J=4.0Hz,1H),8.52–8.42(m,2H),8.12(dd,J=8.1,1.4Hz,1H),8.08–7 .96(m,2H),7.87(d,J=2.0Hz,1H),7.74–7.62(m,3H),7.61–7.47(m,3H),5.21(d,J=3.9Hz,2H),2.65(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 153.4, 142.2, 139.7, 134.7, 131.7, 130.1, 123.0, 129.7, 128.8, 128.6, 127.4, 127.3, 124.7, 124.0, 123.0, 122.0, 119.9, 42.7, 15.7. HRMS (ESI) m / z: calcd. 22 H 19 N2OS2[M+H] + 359.1213, measured value: 359.1211.

[0088] Example 12: Synthesis of Compound 31

[0089]

[0090] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 4'-fluoro-2-isocyano-1,1'-biphenyl 1l (19.7 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0091] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 28.7 mg of the product as a colorless oil with a yield of 87%; 1 H NMR(400MHz,Chloroform-d)δ8.59(dd,J=9.1,5.2Hz,1H),8.54(t,J=4.1Hz,1H),8.46(dd,J=8.2,1.5Hz,1H),8.14(dd,J=8.0,1.5Hz ,1H),8.05–7.99(m,2H),7.79(dd,J=9.3,2.6Hz,1H),7.75–7.70(m,1H),7.69–7.64(m,1H),7.62–7.51(m,4H),5.15(d,J=4.0Hz,2H). 13C NMR(100MHz,Chloroform-d)δ167.3,161.7(d,J=250.0Hz),153.6(d,J=4.0Hz),142.2,134.6,129.7,129.5(d,J=2.0H z),128.9,128.8,127.7,127.32,125.31(d,J=8.5Hz),123.7,122.0,120.5(d,J=23.7Hz),109.6(d,J=21.7Hz),42.7. 19 F NMR (376 MHz, Chloroform-d) δ -110.26–-110.43 (m). HRMS (ESI) m / z: calculated value C 21 H 16 FN2O[M+H] + 331.1241, measured value: 331.1240.

[0092] Example 13: Synthesis of Compound 3m

[0093]

[0094] (1) A magnetic particle was added to a dry 10 mL reaction tube, followed by the addition of 4'-chloro-2-isocyano-1,1'-biphenyl 1m (21.4 mg, 0.1 mmol), N-methyl-N-((4-(trifluoromethyl)benzoyloxy)benzamide 2a (48.4 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), and then the air was evacuated and backfilled with argon (3 times). N,N-dimethylacetamide (1.0 mL) was added, and the reaction tube was transferred to a 450-455 nm wavelength visible light reactor (12 W) and irradiated therein for 24 hours;

[0095] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 29.5 mg of the product as a white solid with a yield of 85% and a melting point of 191-193°C; 1 H NMR(400MHz,Chloroform-d)δ8.70–8.41(m,3H),8.30–8.11(m,2H),8.08–7.99(m,2H),7.83(dd,J =8.9,2.1Hz,1H),7.80–7.74(m,1H),7.73–7.66(m,1H),7.60–7.50(m,3H),5.23(d,J=3.9Hz,2H). 13C NMR (100 MHz, Chloroform-d) δ 167.4, 153.5, 134.6, 134.2, 132.0, 131.7, 131.3, 129.7, 129.4, 128.8, 127.8, 127.4, 125.1, 124.5, 124.4, 123.6, 122.2, 42.6. HRMS (ESI) m / z: calcd. 21 H 16 ClN2O[M+H] + 347.0946, measured value: 347.0942.

[0096] Example 14: Synthesis of Compound 3n

[0097]

[0098] (1) Add a magnetic particle to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-1,1'-biphenyl 1n (17.9 mg, 0.1 mmol), 4-methoxy-N-methyl-N-(((4-(trifluoromethyl)benzoyl)oxy)phenyl)amide 2b (53.0 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), then evacuate the air and backfill with argon (3 times). Add N,N-dimethylacetamide (1.0 mL), transfer the reaction tube to a 450-455 nm wavelength visible light reactor (12 W) and irradiate it for 24 hours;

[0099] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 25.6 mg of the product as a yellow solid with a yield of 85% and a melting point of 229-230°C; 1 H NMR(400MHz,Chloroform-d)δ8.65(d,J=8.3Hz,1H),8.57(dd,J=8.0,1.5Hz,2H),8.26(d,J=8.2Hz,1H),8.19(dd,J=8.1,1.4Hz,1H) ,8.04–7.97(m,2H),7.92–7.87(m,1H),7.79–7.73(m,2H),7.72–7.66(m,1H),7.06–6.97(m,2H),5.28(d,J=3.9Hz,2H),3.89(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 166.9, 162.4, 154.7, 133.0, 131.4, 129.6, 129.1, 129.0, 128.1, 127.3, 127.0, 125.0, 124.23, 124.21, 122.7, 122.3, 113.9, 55.6, 42.7. HRMS (ESI) m / z: calcd. 22 H 19 N2O2[M+H] + 343.1441, measured value: 343.1446.

[0100] Example 15: Synthesis of Compound 3o

[0101]

[0102] (1) Add a magnetic particle to a dry 10 mL reaction tube, then add 2-isocyano-1,1'-biphenyl 1a (17.9 mg, 0.1 mmol), 4-(tert-butyl)-N-methyl-N-((4-(trifluoromethyl)benzoyl)oxy)benzamide 2c (56.9 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), then evacuate the air and backfill with argon (3 times). Add N,N-dimethylacetamide (1.0 mL), transfer the reaction tube to a 450-455 nm wavelength visible light reactor (12 W) and irradiate it for 24 hours;

[0103] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 32.7 mg of the product as a yellow liquid with a yield of 89%; 1 H NMR(400MHz,Chloroform-d)δ8.59(d,J=8.5Hz,2H),8.51(dd,J=8.1,1.5Hz,1H),8.20–8.12(m,2H),8.00–7.94(m,2H),7 .87–7.82(m,1H),7.71(dt,J=6.9,1.3Hz,2H),7.67–7.62(m,1H),7.58–7.51(m,2H),5.24(d,J=4.0Hz,2H),1.39(s,9H). 13C NMR (100 MHz, Chloroform-d) δ 167.3, 155.0, 154.5, 142.5, 132.8, 131.9, 131.2, 129.6, 128.9, 128.0, 127.17, 127.15, 125.7, 124.8, 124.12, 124.10, 122.6, 122.2, 42.7, 35.2, 31.3. HRMS (ESI) m / z: calcd. 25 H 25 N2O[M+H] + 369.1961, measured value: 369.1965.

[0104] Example 16: Synthesis of Compound 3p

[0105]

[0106] (1) Add a magnetic particle to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-1,1'-biphenyl 1p (17.9 mg, 0.1 mmol), 4-chloro-N-methyl-N-((4-(trifluoromethyl)benzoyl)oxy)aniline amide 2d (53.7 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), then evacuate the air and backfill with argon (3 times). Add N,N-dimethylacetamide (1.0 mL), transfer the reaction tube to a 450-455 nm wavelength visible light reactor (12 W) and irradiate it for 24 hours;

[0107] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 23.8 mg of the product as a yellow solid with a yield of 69% and a melting point of 223-225°C; 1 H NMR(400MHz,Chloroform-d)δ8.65(t,J=5.9Hz,2H),8.58–8.53(m,1H),8.23–8.13(m,2H),7.96(d,J=8.4Hz,2 H),7.89(t,J=7.7Hz,1H),7.78–7.72(m,2H),7.71–7.66(m,1H),7.49(d,J=8.4Hz,2H),5.25(d,J=3.8Hz,2H). 13C NMR (100 MHz, Chloroform-d) δ 166.3, 154.2, 142.5, 137.9, 133.1, 132.9, 131.4, 129.6, 129.1, 129.0, 128.8, 128.1, 127.4, 124.8, 124.2, 124.1, 122.7, 122.3, 42.7. HRMS (ESI) m / z: calcd. 21 H 16 ClN2O[M+H] + 347.0946, measured value: 347.0943.

[0108] Example 17: Synthesis of Compound 3q

[0109]

[0110] (1) Add a magnetic particle to a dry 10 mL reaction tube, then add 2-isocyano-1,1'-biphenyl 1a (17.9 mg, 0.1 mmol), N,3-dimethyl-N-((4-(trifluoromethyl)benzoyl)oxy)aniline 2e (50.6 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), then evacuate the air and backfill with argon (3 times). Add N,N-dimethylacetamide (1.0 mL), transfer the reaction tube to a 450-455 nm wavelength visible light reactor (12 W) and irradiate it for 24 hours;

[0111] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 25.5 mg of the product as a white solid with a yield of 78% and a melting point of 209-211°C; 1 H NMR(400MHz,Chloroform-d)δ8.21–8.16(m,1H),8.13(dd,J=8.1,1.4Hz,1H),7.88–7.78(m,3H),7.7 5–7.68(m,2H),7.68–7.63(m,1H),7.40(dt,J=15.0,7.6Hz,2H),5.23(d,J=3.9Hz,2H),2.47(s,3H). 13C NMR (100 MHz, Chloroform-d) δ 167.5, 154.4, 142.5, 138.6, 134.7, 132.8, 132.4, 131.2, 129.6, 128.9, 128.6, 128.2, 128.0, 127.2, 124.8, 124.2, 124.1, 122.6, 122.3, 42.7, 21.6. HRMS (ESI) m / z: calcd. 22 H 19 N2O[M+H] + 327.1492, measured value: 327.1496.

[0112] Example 18: Synthesis of Compound 3r

[0113]

[0114] (1) Add a magnetic particle to a dry 10 mL reaction tube, followed by the addition of 2-isocyano-1,1'-biphenyl 1a (17.9 mg, 0.1 mmol), 2-fluoro-N-methyl-N-((4-(trifluoromethyl)benzoyl)oxy)aniline amide 2f (51.2 mg, 0.15 mmol), triethylenediamine (22.4 mg, 0.2 mmol), bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (5.6 mg, 0.005 mmol), then evacuate the air and backfill with argon (3 times). Add N,N-dimethylacetamide (1.0 mL), transfer the reaction tube to a 450-455 nm wavelength visible light reactor (12 W) and irradiate it for 24 hours;

[0115] (2) After the reaction was completed, the product was directly separated and purified by silica gel column chromatography to obtain 20.8 mg of the product as a white solid with a yield of 63% and a melting point of 217-218°C; 1 H NMR(400MHz,Chloroform-d)δ9.28(d,J=11.1Hz,1H),8.66(d,J=8.3Hz,1H),8.57(dd,J=8.2,1.4Hz,1H),8.37–8.07(m,3H),7.93– 7.85(m,1H),7.79–7.73(m,2H),7.71–7.65(m,1H),7.57–7.50(m,1H),7.35–7.29(m,1H),7.27–7.20(m,1H),5.35(d,J=3.8Hz,2H). 13C NMR (100MHz, Chloroform-d) δ 163.3 (d, J = 3.0Hz), 161.3 (d, J = 249.2Hz), 154.0, 133.4 (d, J = 9.1Hz), 132.1 (d, J = 2.2Hz), 130.5 (d, J =143.3Hz), 129.0, 128.0, 127.3, 124.8 (d, J = 3.5Hz), 124.1 (d, J = 1.5Hz), 122.7, 122.2, 121.4 (d, J = 11.6Hz), 116.3 (d, J = 24.4Hz). 19 F NMR (376 MHz, Chloroform-d) δ-112.64. HRMS (ESI) m / z: calculated value C 21 H 16 FN2O[M+H] + 331.1241, measured value: 331.1244.

[0116] Experimental Example 1: Exploration of reaction conditions

[0117]

[0118] Based on the above reaction, we explored how to choose photosensitizer, base, light source, solvent, and illumination time to obtain a higher yield of the product. The design and results of different groups are shown in the table below.

[0119] 1. Exploration of photosensitizers

[0120] Table 1

[0121]

[0122]

[0123] From Table 1, we can see that:

[0124] Best embodiment 1: The selected photosensitizer is bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt (photosensitizer equivalent is 0.5 mol%), the base is triethylenediamine (base equivalent is 3), 450-455 nm light source and N, N-dimethylacetamide solvent (solvent volume is 1.0 mL) are selected, the reaction time is 24 h, and the yield is 76%.

[0125] Comparative Example 1: The photosensitizer was replaced with 10-phenyl-10H-phenothiazine, and the other conditions were the same as those in Example 1, with a yield of 64%;

[0126] Comparative Example 2: The photosensitizer was replaced with red Y, and the other conditions were the same as those in Example 1, and the yield was <10%;

[0127] Comparative Example 3: The photosensitizer was replaced with fac-tri(2-phenylpyridine)iridium, and the other conditions were the same as those in Example 1, with a yield of 59%;

[0128] Comparative Example 4: The photosensitizer was replaced with Bengal Rose Red, and the other conditions were the same as in Example 1, with a yield of 52%;

[0129] Comparative Example 5: No photosensitizer was added, and other conditions were the same as those in Example 1, and no reaction occurred;

[0130] Comparative Example 6: The concentration of the photosensitizer was increased to 0.3 mol %, and other conditions were the same as those in Example 1, with a yield of 54%.

[0131] Conclusion: The bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt photosensitizer is significantly superior to traditional photosensitizers, and the amount of the photosensitizer is preferably 0.5-1.0 mol% of the molar amount of 2-arylphenyl isocyanide.

[0132] 2. Exploration of alkali

[0133] Table 2

[0134]

[0135]

[0136] From Table 2, we can see that:

[0137] Comparative Example 7: The base was replaced with sodium bicarbonate, and the other conditions were the same as those in the best example 1, and the yield was <10%;

[0138] Comparative Example 8: The base was replaced with sodium carbonate, and the other conditions were the same as those in the best example 1, with a yield of 56%;

[0139] Comparative Example 9: The base was replaced with potassium phosphate, and the other conditions were the same as those in the best example 1, with a yield of 48%;

[0140] Comparative Example 10: The base was replaced with triethylamine, and the other conditions were the same as those in the best example 1, and the yield was <10%;

[0141] Comparative Example 11: the base was replaced by N,N-diisopropylethylamine, the other conditions were the same as those in the best embodiment 1, and the yield was <10%); Comparative Example 12: the base was replaced by 4-dimethylaminopyridine, the other conditions were the same as those in the best embodiment 1, and the yield was <10%.

[0142] Comparative Example 13: No base was used, other conditions were the same as in Example 1, and no reaction occurred.

[0143] Comparative Example 14: The base equivalent was reduced to 1.5 equivalents, and other conditions were the same as those in the best example 1, with a yield of 59%.

[0144] Conclusion: Triethylenediamine is the only efficient base.

[0145] 3. Light source wavelength adjustment

[0146] Table 3

[0147]

[0148]

[0149] From Table 3, we can see that:

[0150] Comparative Example 15: The wavelength of the light source is adjusted to 390-395nm, and the other conditions are the same as the best example 1, and the yield is 47%. Comparative Example 16: The wavelength of the light source is adjusted to 420-425nm, and the other conditions are the same as the best example 1, and the yield is 55%; Comparative Example 17: The wavelength of the light source is adjusted to 520-525nm, and the other conditions are the same as the best example 1, and the yield is 49%; Conclusion: The 450-455nm light source has the highest yield.

[0151] 4. Solvent replacement

[0152] Table 4

[0153]

[0154]

[0155] From Table 4, we can see that:

[0156] Comparative Example 18: The solvent was replaced with dimethyl sulfoxide, and the other conditions were the same as those in the best example 1, with a yield of 67%; Comparative Example 19: The solvent was replaced with tetrahydrofuran, and the other conditions were the same as those in the best example 1, with a yield of 63%;

[0157] Comparative Example 20: The solvent was replaced with acetonitrile, and the other conditions were the same as those in the best example 1, with a yield of 65%;

[0158] Comparative Example 21: The solvent was replaced with 1,4-dioxane, and the other conditions were the same as those in the best example 1, and the yield was <10%; in Comparative Example 22, the solvent was only 0.2 mL, and the other conditions were the same as those in the best example 1, and the yield was 68%. Conclusion: N,N-dimethylacetamide is the best solvent.

[0159] 5. Adjustment of reaction time

[0160] Table 5

[0161]

[0162] From Table 5, we can see that:

[0163] Comparative Example 23: The reaction time was adjusted to 18 h, and the other conditions were the same as those in the optimal embodiment 1, with a yield of 67%; Comparative Example 24: The reaction time was adjusted to 12 h, and the other conditions were the same as those in the optimal embodiment 1, with a yield of 46%; Conclusion: The reaction time is preferably 24 h, and 24 h is the equilibrium point.

[0164] 6. Controlled Experiment

[0165] Table 6

[0166]

[0167]

[0168] From Table 6, we can see that:

[0169] Comparative Example 25: Air condition, other conditions are the same as those in the best embodiment 1, yield <10%;

[0170] Comparative Example 26: Dark conditions, other conditions are the same as those in the best embodiment 1, no reaction;

[0171] Conclusion: Argon protection and illumination are necessary conditions.

[0172] In summary, the optimal conditions are: photosensitizer: bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate), base: triethylenediamine; light source: 450-455nm; solvent: N,N-dimethylacetamide, duration: 24h.

[0173] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0174] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0175] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis, characterized in that: The method comprises: using 2-arylphenyl isocyanate and isohydroxamate as raw materials, carrying out a photocatalytic reaction under the conditions of a photosensitizer, a base and a solvent, visible light irradiation and argon protection, to synthesize N-(phenanthridin-6-ylmethyl)benzamide compounds, wherein the chemical reaction formula is: in: R1 is selected from hydrogen, methoxy, methyl, tert-butyl; R2 is selected from hydrogen, halogen, methoxy, methyl, tert-butyl, n-butyl, thiomethyl or phenoxy; R3 is selected from hydrogen, halogen, methoxy, tert-butyl, methyl, cyclohexane, cyclopentane.

2. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The solvent is N,N-dimethylethylamine.

3. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The base is triethylenediamine.

4. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The photosensitizer is bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bipyridine]iridium di(hexafluorophosphate) salt.

5. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The amount of the photosensitizer used is 0.5-1.0 mol% of the molar amount of 2-arylphenylisocyanate.

6. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The molar ratio of the 2-arylphenyl isocyanate:hydroxamate:base is 1:(1.5-2.0):(1.5-3.0).

7. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The reaction concentration of the 2-arylphenyl isocyanide is 0.05-0.2 mol / L.

8. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The wavelength of the visible light is 450-455nm, and the power is 12W.

9. The method for synthesizing N-(phenanthridin-6-ylmethyl)benzamide compounds by visible light catalysis according to claim 1, characterized in that: The photocatalytic reaction time is 24 hours.

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