Catalyst-free photoreaction method based on pyrrolo [1, 2-a] quinoxaline and derivative thereof and azo compound and product

Abstract

The invention provides a catalyst-free photoreaction method based on pyrrolo [1, 2-a] quinoxaline and a derivative thereof and an azo compound, and a product, and belongs to the technical field of chemistry. The pyrrolo [1, 2-a] quinoxaline and the derivative thereof are used, amination reaction of the azo compound is realized under the condition of visible light induction, formation of C-N bonds can be directly and efficiently induced through blue light (456nm), a new strategy is provided for C-N coupling reaction of the pyrrolo [1, 2-a] quinoxaline and the derivative thereof with the azo compound, the highest yield can reach 95%, and the method is suitable for industrial production. Compared with the existing method for catalyzing the amination reaction by using catalysts such as super acid, noble metal and fluorine-containing solvent, the method disclosed by the invention is safe and mild in reaction condition, green and environment-friendly, conforms to the green chemistry concept, and is beneficial to reducing the energy consumption and the environmental influence.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology, and in particular to a catalyst-free photoreaction method and product based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds. Background Art

[0002] Azo compounds have become an indispensable part of organic synthesis due to their unique structure and properties. They can not only be used as oxidants and coupling partners to participate in heterocyclic synthesis, but also as nitrogen sources to complete the amination reaction of aromatic compounds. At present, Kim's team first reported the use of superacid TfOH as a promoter to achieve the amination reaction of non-activated aromatic hydrocarbons in 2001. Since then, researchers have achieved the amination reaction of aromatic hydrocarbons by azodicarboxylates through metal catalysis (such as gold, ruthenium, silver, potassium, etc.), or carried out the 4-position amination reaction of aniline through the fluorinated solvent HFIP. In addition, there are also studies reporting the completion of the C1-amination reaction of 2-aryl imidazo[1,2-a]pyridine by transition metal-free catalysis at a temperature of 80°C. However, the special reaction conditions such as superacids, precious metal catalysts and fluorinated solvents used in the existing technology not only increase the reaction cost, but also have potential negative impacts on the environment.

[0003] Visible-light-promoted reactions have attracted increasing attention in recent years due to their ease of operation and mild conditions. However, no one has yet used visible light to promote the amination of azo compounds. Therefore, developing a catalyst-free, green, efficient, and safe photocatalytic reaction method is of great research significance and application value. Summary of the Invention

[0004] The purpose of the present invention is to provide a catalyst-free photoreaction method and product based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds. Using pyrrolo[1,2-a]quinoxaline and its derivatives, the amination reaction of the azo compound is achieved under visible light-induced conditions, and the formation of C-N bonds can be efficiently induced directly by blue light (456 nm).

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a catalyst-free photoreaction method based on pyrrolo[1,2-a]quinoxaline and its derivatives with an azo compound. The catalyst-free photoreaction method is to induce an amination reaction between pyrrolo[1,2-a]quinoxaline and its derivatives represented by formula (I) and the azo compound represented by formula (II) under light conditions. The reaction formula is as follows:

[0007]

[0008] Preferably, the R 1 It is a substituent at position 7 on the benzene ring, including one of H, Me, and Cl;

[0009] The R 2 Including one of H, 4-phenyl, 4-Mephenyl, and 4-Brphenyl;

[0010] The R 3 Including one of Et, iPr, Bn, and (CH2)2OCH3.

[0011] Preferably, the molar ratio of the compound represented by formula (I) to the compound represented by formula (II) is 1-2:2-4.

[0012] Preferably, the light condition is: visible light.

[0013] Preferably, the visible light is: blue light 456nm.

[0014] The present invention also provides a product prepared by a catalyst-free photoreaction method of pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds.

[0015] The beneficial effects of the present invention compared with the prior art are:

[0016] (1) The present invention uses pyrrolo[1,2-a]quinoxaline and its derivatives to achieve the amination reaction of azo compounds under visible light-induced conditions. The formation of C-N bonds can be efficiently induced directly by blue light (456 nm), providing a new strategy for the C-N coupling reaction of pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds, with a maximum yield of up to 95%.

[0017] (2) The present invention adopts a milder blue light catalysis, which not only avoids the low-band deep ultraviolet catalysis, but also has safe and mild reaction conditions, which are green and environmentally friendly compared with the existing methods using catalysts such as superacids, precious metals and fluorinated solvents to catalyze the amination reaction. It can even use sunlight as a light source and still achieve a high yield. It provides a new route for the amination reaction of pyrrolo[1,2-a]quinoxaline and its derivatives that is simple to operate, mild in conditions and green and environmentally friendly, which is in line with the concept of green chemistry and helps to reduce energy consumption and environmental impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a diagram of the synthesis method of diethyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate in Example 1 of the present invention;

[0020] Figure 2 is the H NMR spectrum of diethyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate;

[0021] Figure 3 is the C NMR spectrum of diethyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate;

[0022] Figure 4 This is a diagram of the synthesis method of diethyl-1-(4-phenylpyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate according to Example 2 of the present invention;

[0023] Figure 5 This is a diagram of diethyl-1-(4-(p-tolyl)pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate according to Example 3 of the present invention;

[0024] Figure 6 This is a diagram of diethyl-1-(4-(4-bromophenyl)pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate according to Example 4 of the present invention;

[0025] Figure 7 This is a diagram of diethyl-1-(7-methylpyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate according to Example 5 of the present invention;

[0026] Figure 8 This is a diagram of diethyl-1-(7-chloropyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate according to Example 6 of the present invention;

[0027] Figure 9 This is a diagram of diisopropyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate according to Example 7 of the present invention;

[0028] Figure 10 This is a diagram of bis(2-methoxyethyl)-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate according to Example 8 of the present invention;

[0029] Figure 11 This is a diagram of benzhydryl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate according to Example 9 of the present invention. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0032] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0033] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0034] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] Example 1

[0036] Example 1 of the present invention provides a method for synthesizing diethyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 1 The specific steps are as follows:

[0037] A 10 mL branched quartz reaction tube was charged with pyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0336 g). Under argon, diethyl azodicarboxylate (0.4 mmol, 0.0697 g) and DMSO (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion, the reaction solution was diluted with 15 mL of ethyl acetate, and the organic phase was extracted three times with 10 mL of saturated sodium chloride solution. The organic layer was then dried over anhydrous Na2SO4, and the solvent was removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 3:1) to obtain 63.8 mg of diethyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate in a 94% yield.

[0038] And characterized it, the results are as follows Figure 2 、 3 shown.

[0039] Diethyl-1-(pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR(400MHz, CDCl3)δ8.76(s,1H),8.14(s,1H),8.01-7.92(m,1H),7.80(s,1H),7.48-7.3 7(m,2H),7.04(s,1H),6.87(d,J=4.0Hz,1H),4.23(s,4H),1.32-1.22(m,3H),1.09(s,3H); 13 C NMR (101MHz, CDCl3) δ156.03,155.72,145.93,136.76,130.27,128.31,128.20 ,128.05,125.59,124.84,114.88,113.57,106.58,64.12,62.64,14.52,14.45.

[0040] Example 2

[0041] Example 2 of the present invention provides a method for synthesizing diethyl-1-(4-phenylpyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 4 The specific steps are as follows:

[0042] A 10 mL branched quartz reaction tube was charged with 4-phenylpyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0489 g). Under argon, diethyl azodicarboxylate (0.4 mmol, 0.0697 g) and solvent (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 4:1) to obtain 68.4 mg of the final product, diethyl-1-(4-phenylpyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in an 85% yield.

[0043] Diethyl-1-(4-phenylpyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR (400MHz, CDCl3) δ8.16-8.04(m,2H),7.94(dd,J=6.4,4.0Hz,2H),7.53(dd,J=4.8,1.2Hz,3H),7.48(dd,J=6.0, 3.2Hz,2H),7.34(s,1H),7.05(s,1H),6.95(d,J=4.4Hz,1H),4.35-4.19(m,4H),1.29(t,J=7.2Hz,3H),1.15(s,3H); 13 C NMR (101MHz, CDCl3) δ155.96,155.74,154.63,137.79,137.14,130.46,129.90,128.78,128.63 ,128.38,127.65,127.46,125.58,123.89,114.46,113.47,107.79,64.10,62.59,14.53,14.49.

[0044] Example 3

[0045] Example 3 of the present invention provides a method for synthesizing diethyl-1-(4-(p-tolyl)pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 5 The specific steps are as follows:

[0046] A 10 mL branched quartz reaction tube was charged with 4-(p-tolyl)pyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0517 g). Under argon, diethyl azodicarboxylate (0.4 mmol, 0.0697 g) and solvent (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 4:1) to obtain 94.2 mg of the final product, diethyl-1-(4-(p-tolyl)pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in a yield of 72%.

[0047] Diethyl-1-(4-(p-tolyl)pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR (400MHz, CDCl3) δ8.10(s,1H),8.07-8.02(m,1H),7.82(s,1H),7.80(s,1H),7.61(d,J=9.6Hz,1H),7.41(s,2H) ,7.31(s,1H),7.29(s,1H),7.04(s,1H),6.93(d,J=4.4Hz,1H),4.25(s,4H),2.43(s,3H),1.26(s,3H),1.12(s,3H); 13 C NMR (101MHz, CDCl3) δ155.93,155.76,154.56,140.08,137.08,134.88,130.31,129.31,128.75,12 8.35,127.49,127.41,125.54,123.89,114.42,113.47,107.86,64.08,62.58,21.56,14.54,14.49.

[0048] Example 4

[0049] Example 4 of the present invention provides a method for synthesizing diethyl-1-(4-(4-bromophenyl)pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 6 The specific steps are as follows:

[0050] A 10 mL branched quartz reaction tube was charged with 4-(4-bromophenyl)pyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0646 g). Under argon, diethyl azodicarboxylate (0.4 mmol, 0.0697 g) and solvent (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 4:1) to obtain 51.7 mg of the final product, diethyl-1-(4-(4-bromophenyl)pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in a yield of 58%.

[0051] Diethyl-1-(4-(4-bromophenyl)pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR (400MHz, CDCl3) δ8.19-8.00(m,2H),7.83(d,J=8.4Hz,2H),7.66(d,J=8.4Hz,2H),7.47(dd,J=6.4,3.6H z,2H),7.40(s,1H),7.06(s,1H),6.91(d,J=4.4Hz,1H),4.44-4.14(m,4H),1.36-1.26(m,3H),1.14(s,3H); 13 C NMR (101MHz, CDCl3) δ155.97,155.69,153.34,136.91,136.55,131.79,130.40,130.35,128.65 ,127.83,127.40,125.68,124.35,123.46,114.57,113.59,107.61,64.12,62.60,14.54,14.48.

[0052] Example 5

[0053] Example 5 of the present invention provides a method for synthesizing diethyl-1-(7-methylpyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 7 The specific steps are as follows:

[0054] A 10 mL branched quartz reaction tube was charged with 7-methylpyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0364 g). Under argon, diethyl azodicarboxylate (0.4 mmol, 0.0697 g) and solvent (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 3:1) to obtain 60.6 mg of the final product, diethyl-1-(7-methylpyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in an 85% yield.

[0055] Diethyl-1-(7-methylpyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR (400MHz, CDCl3) δ8.74(s,1H),7.96(s,1H),7.77(s,1H),7.40(s,1H),7.28(dd,J=8.8,2.0Hz,1H) ,7.00(s,1H),6.85(d,J=4.4Hz,1H),4.29-4.19(m,4H),2.47(s,3H),1.30-1.25(m,3H),1.11(s,3H); 13 C NMR (101MHz, CDCl3) δ156.09,155.75,145.85,145.02,136.70,135.41,129.95,129.11 ,127.88,126.05,124.72,114.58,113.22,106.29,64.02,62.53,20.99,14.52,14.46.

[0056] Example 6

[0057] Example 6 of the present invention provides a method for synthesizing diethyl-1-(7-chloropyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 8 The specific steps are as follows:

[0058] A 10 mL branched quartz reaction tube was charged with 7-chloropyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0405 g). Under argon, diethyl azodicarboxylate (0.4 mmol, 0.0697 g) and solvent (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 3:1) to obtain 52.8 mg of the final product, diethyl-1-(7-chloropyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in a yield of 73%.

[0059] Diethyl-1-(7-chloropyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 HNMR (400MHz, CDCl3) δ8.76 (s, 1H), 8.14 (s, 1H), 7.96 (d, J = 2.4Hz, 1H), 7.43 (dd, J = 9.2, 2.4Hz, 1H), 7.3 8(s,1H),7.02(s,1H),6.91(d,J=4.4Hz,1H),4.25(d,J=6.4Hz,4H),1.28(t,J=7.2Hz,3H),1.12(s,3H); 13 C NMR (101MHz, CDCl3) δ156.16,155.63,146.91,137.78,130.76,129.36,128.70 ,127.87,126.81,124.62,116.46,113.56,107.27,64.26,62.71,14.53,14.46.

[0060] Example 7

[0061] Example 7 of the present invention provides a method for synthesizing diisopropyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 9 The specific steps are as follows:

[0062] A 10 mL branched quartz reaction tube was charged with pyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0336 g). Under argon, diisopropyl azodicarboxylate (0.4 mmol, 0.0809 g) and solvent (1 mL) were added. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 4:1) to obtain 51.5 mg of the final product, diisopropyl-1-(pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in a yield of 71%.

[0063] Example 8

[0064] Example 8 of the present invention provides a method for synthesizing bis(2-methoxyethyl)-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 10 The specific steps are as follows:

[0065] A 10 mL branched quartz reaction tube was charged with pyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0336 g). Bis-2-methoxyethyl azodicarboxylate (0.4 mmol, 0.0937 g) and solvent (1 mL) were added under argon. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 4:1) to obtain 56.4 mg of the final product, bis(2-methoxyethyl)-1-(pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in a 95% yield.

[0066] Bis(2-methoxyethyl)-1-(pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR(400MHz, CDCl3)δ8.76(s,1H),8.14(s,1H),7.97(dd,J=7.2,2.5Hz,1H),7.92(s,1H),7.46-7.43(m,1H),7.05(d, J=4.4Hz,1H),6.96(s,1H),6.86(d,J=4.4Hz,1H),4.31(d,J=4.4Hz,4H),3.63-3.54(m,4H),3.35(s,3H),3.32(s,3H); 13C NMR (101MHz, CDCl3) δ156.67,155.74,155.51,145.87,136.69,130.18,128.25,128.07,127.97,125. 58,124.85,114.97,113.62,106.60,70.57,70.46,70.19,66.80,65.28,65.02,58.94,58.91,58.87.

[0067] Example 9

[0068] Example 9 of the present invention provides a method for synthesizing diphenylmethyl-1-(pyrrolo[1,2-a]quinoxaline-1-yl)hydrazine-1,2-dicarboxylate, such as Figure 11 The specific steps are as follows:

[0069] A 10 mL branched quartz reaction tube was charged with pyrrolo[1,2-a]quinoxaline (0.2 mmol, 0.0336 g). Benzomethyl (E)-diazene-1,2-dicarboxylate (0.4 mmol, 0.1193 g) and solvent (1 mL) were added under argon. The mixture was stirred at room temperature under a 456 nm light source for 24 hours. After completion of the reaction, the organic phase was extracted with ethyl acetate (15 mL x 3) and saturated sodium chloride solution (10 mL). The organic layer was then dried over anhydrous Na2SO4 and the solvent removed under reduced pressure. The crude product was purified by silica gel flash chromatography (petroleum ether / ethyl acetate = 4:1) to obtain 40.8 mg of the final product, benzhydryl-1-(pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate, in a yield of 48%.

[0070] Benzhydryl-1-(pyrrolo[1,2-a]quinoxalin-1-yl)hydrazine-1,2-dicarboxylate: 1 H NMR (400MHz, CDCl3) δ8.73(s,1H),8.01(s,1H),7.94(dd,J=8.0,1.6Hz,1H),7.82(s,1H),7.48-6.92(m,13H),6.85(s,1H),5.19(q,J=11.6Hz,4H); 13 C NMR (101MHz, CDCl3) δ155.90,155.58,145.79,136.53,135.32,135.10,130.06,128.67,128. 54,128.27,128.12,128.05,127.90,125.56,124.82,114.84,113.74,106.73,69.36,68.22.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A catalyst-free photoreaction method based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds, characterized in that: The catalyst-free photoreaction method is to induce an amination reaction between the pyrrolo[1,2-a]quinoxaline and its derivatives represented by formula (I) and the azo compound represented by formula (II) under light conditions. The chemical reaction formula is as follows:

2. The catalyst-free photoreaction method based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds according to claim 1, characterized in that: The R 1 It is a substituent at position 7 on the benzene ring, including one of H, Me, and Cl; The R 2 Including one of H, 4-phenyl, 4-Mephenyl, and 4-Brphenyl; The R 3 Including one of Et, iPr, Bn, and (CH2)2OCH3.

3. The catalyst-free photoreaction method based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds according to claim 1, characterized in that: The molar ratio of the compound represented by formula (I) to the compound represented by formula (II) is 1-2:2-4.

4. The catalyst-free photoreaction method based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds according to claim 1, characterized in that: The light condition is: visible light.

5. The catalyst-free photoreaction method based on pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds according to claim 4, characterized in that: The visible light is: blue light 456nm.

6. A product prepared by the catalyst-free photoreaction method of pyrrolo[1,2-a]quinoxaline and its derivatives with azo compounds as claimed in any one of claims 1 to 5.

Images