Preparation method and application for photocatalytic synthesis of aza-aromatic compounds

Abstract

The invention discloses a preparation method for photocatalytic synthesis of an aza-aromatic compound and application of the aza-aromatic compound. The preparation method comprises the following steps: mixing an isonitrile compound, an alkyl boric acid reagent, a photosensitizer, an alkali reagent and a solvent, and reacting under the irradiation of visible light to obtain the aza-aromatic compound. The synthesis method has the advantages of easily available raw materials, simple operation, mild reaction, wide substrate applicability and the like, and the obtained indole / pyrrolo [1, 2-a] quinoxaline compound has fluorescence property.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a preparation method and application of a photocatalytically synthesized nitrogen heteroaromatic compound. Background Art

[0002] Azaaromatic compounds have rich pharmacological properties in the pharmaceutical fields of anti-cancer, anti-diabetes, and anti-tuberculosis. The corresponding derivatives also have good development prospects in electronic and optical applications. However, there are few reports on the synthesis of azaaromatic compounds with different functionalizations. It is of great research significance to develop a novel, simple and sustainable synthetic route for the synthesis of this type of compounds. Summary of the invention

[0003] The purpose of the present invention is to provide a preparation method and application of photocatalytically synthesized nitrogen heteroaromatic compounds; the nitrogen heteroaromatic compounds include indole / pyrrolo[1,2-a]quinoxaline compounds, phenanthridine compounds and benzothiazole compounds.

[0004] The technical solution adopted by the present invention is:

[0005] A method for preparing a nitrogen heteroaromatic compound by photocatalytic synthesis comprises the following steps:

[0006] An isonitrile compound, an alkyl boronic acid reagent, a photosensitizer, an alkali reagent and a solvent are mixed and reacted under the irradiation of visible light to obtain an azaaromatic compound;

[0007] The structural formula of the isonitrile compound is as follows:

[0008]

[0009] The structural formula of the alkyl boronic acid reagent is as follows:

[0010]

[0011] The structural formula of the nitrogen heteroaromatic compound is as follows:

[0012]

[0013] In the formula, R 1 is selected from one of hydrogen, alkyl, alkoxy, halogen, and cyano, Ar 1 and Ar 2 The substituents are independently selected from one or two of hydrogen, alkyl, alkoxy, halogen, and cyano, X is selected from one of C and N, and R is selected from an alkyl.

[0014] Preferably, R 1 ,Ar 1 and Ar2 Among the substituents above, the carbon number of the alkyl group (including straight chain, branched chain and cycloalkyl group) is 1 to 6, the carbon number of the alkoxy group is 1 to 6 (the alkyl group in the alkoxy group includes straight chain, branched chain and cycloalkyl group), and the halogen is fluorine, chlorine, bromine or iodine.

[0015] Preferably, in R, the alkyl group is a straight-chain alkyl group, a branched-chain alkyl group or a cycloalkyl group, the straight-chain alkyl group has 1 to 6 carbon atoms, the branched-chain alkyl group has 3 to 6 carbon atoms, and the cycloalkyl group has 3 to 8 carbon atoms.

[0016] Preferably, the structural formula of the isonitrile compound is as follows:

[0017]

[0018] The structural formula of the alkyl boronic acid reagent is as follows:

[0019]

[0020] The structural formula of the nitrogen heteroaromatic compound is as follows:

[0021]

[0022] In the formula, Ar 1 and Ar 2 The substituents are independently selected from one or two of H, Me, MeO, F, Cl, and CN, X is selected from one of C and N, and R is selected from one of cyclohexyl, cyclopentyl, and n-butyl.

[0023] Preferably, the alkyl boronic acid reagent is in a chain or ring shape.

[0024] Preferably, the molar ratio of the isonitrile compound, the alkyl boronic acid reagent, the photosensitizer, and the alkali reagent is 1:1-5:0.01-0.10:1-3.

[0025] Preferably, the concentration of the isonitrile compound is 50-100 mM.

[0026] Preferably, the photosensitizer is at least one of 3,6-di-tert-butyl-9-mesityl-10-phenylacridine perchlorate, 2,4,5,6-tetra(carbazole-9-yl)-1,3-dicyanobenzene, 2',4',5',7'-tetrabromo-3',6'-dihydroxy-3H-spiro[isobenzofuran-1,9'-xanthene]-3-one, 2',4',5',7'-tetrabromo-3-oxo-3H-spiro[isobenzofuran-1,9'-xanthene]-3',6'-bis(phenol) disodium salt, and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium hexafluorophosphate;

[0027] Preferably, the alkaline reagent is at least one of sodium carbonate, sodium acetate, potassium carbonate, cesium carbonate, potassium phosphate, DBU, and triethylamine;

[0028] Preferably, the solvent is at least one of tetrahydrofuran, acetonitrile, toluene, dichloroethane, methanol, dimethyl sulfoxide and dioxane.

[0029] Preferably, the wavelength of the visible light is at least one of 380 to 525 nm.

[0030] Further preferably, the wavelength band of the visible light is at least one of 380nm-390nm, 440nm-445nm, 450nm-455nm, and 515nm-525nm.

[0031] Preferably, the reaction temperature is 10°C to 80°C, and the reaction time is 8h to 18h.

[0032] Preferably, the reaction is carried out at a stirring speed of 300 rpm to 700 rpm.

[0033] Preferably, after the reaction is completed, the reaction product is separated and purified.

[0034] Further preferably, the specific operations of separation and purification are: extracting the reaction solution with ethyl acetate, drying with anhydrous Na2SO4, and distilling under reduced pressure, and purifying the crude product obtained by distillation under reduced pressure by column chromatography;

[0035] More preferably, the eluent used in the column chromatography consists of petroleum ether and ethyl acetate in a volume ratio of 3 to 50:1.

[0036] The nitrogen heteroaromatic compounds prepared by the above preparation method.

[0037] The above-mentioned azaaromatic compounds are used as luminescent materials or in the preparation of imaging agents. The structural formula of the azaaromatic compounds is as follows (indole / pyrrolo[1,2-a]quinoxaline compounds):

[0038]

[0039] In the formula, Ar 1 and Ar 2 The substituents are independently selected from one or two of hydrogen, alkyl, alkoxy, halogen, and cyano, X is selected from one of C and N, and R is selected from an alkyl.

[0040] The principle of the present invention is as follows: under visible light irradiation, a free radical cation intermediate is generated under the interaction of the base and the photocatalyst, and then an alkyl free radical is formed under the interaction with the alkyl boronic acid, and then a free radical tandem cyclization process occurs with various aromatic isonitriles to generate the final nitrogen heteroaromatic compound.

[0041] The beneficial effects of the present invention are as follows: the present invention synthesizes a series of nitrogen heteroaromatic compounds and drug molecules containing different substituents. The synthesis method thereof has the advantages of easy availability of raw materials, simple operation, mild reaction, wide substrate applicability, etc., and has good application prospects in the synthesis of organic luminescent materials and other analogs. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 , Figure 2 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 1.

[0043] Figure 3 , Figure 4 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 2.

[0044] Figure 5 , Figure 6 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 3.

[0045] Figure 7 , Figure 8 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 5.

[0046] Fig. 9 , Fig.10 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 6.

[0047] Fig.11 , Fig.12 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 7.

[0048] Fig.13 , Fig.14 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 8.

[0049] Fig.15 , Fig.16 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 9.

[0050] Fig.17 , Fig.18 , Fig.19 They are respectively the hydrogen spectrum, carbon spectrum and fluorine spectrum of the target product obtained in Example 10.

[0051] Fig. 20 , Fig.21They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 11.

[0052] Fig. 22 , Fig.23 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 12.

[0053] Fig.24 , Fig.25 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 13.

[0054] Fig.26 , Fig. 27 , Fig.28 They are respectively the hydrogen spectrum, carbon spectrum and fluorine spectrum of the target product obtained in Example 14.

[0055] Fig.29 , Fig.30 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 15.

[0056] Fig.31 , Fig.32 They are respectively the hydrogen spectrum and carbon spectrum of the target product obtained in Example 16.

[0057] Fig.33 The fluorescence emission spectra of the target products indole / pyrrolo[1,2-a]quinoxaline compounds in Examples 4, 5, 6, 7 and 8 are shown in FIG. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings, but the protection scope and implementation methods of the present invention are not limited thereto.

[0059] Embodiment 1:

[0060] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0061] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 94%).

[0062] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are as follows Figure 1 As shown and Figure 2 As shown, the spectrum analysis data is as follows:

[0063] 1 H NMR (400MHz, CDCl3) δ8.50–8.47(m,2H),8.03(d,J=7.6Hz,1H),7.98(d,J=8.0Hz,1H),7.57(dt,J=14.4,7.2Hz,2H),7.45(q,J=7.6Hz,2H),7.26 (s,1H),3.31–3.25(m,1H),2.13(d,J=13.2Hz,2H),1.99(d,J=14.8Hz,2 H),1.90(dd,J=24.8,12.8Hz,3H),1.62–1.55(m,2H),1.52–1.43(m,1H).

[0064] 13 C NMR (100MHz, CDCl3) δ162.4,132.9,130.1,129.9,129.2,129.0,127.6,123.9,122.5,122.5,114.6,114.5,99.2,43.3,31.2,26.6,26.1.

[0065] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0066] IR(KBr) Vmax :2927,2851,2361,1743,1532,1447,1401,1241,1048,744cm -1 .

[0067] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0068] HRMS (APCI) calculation for C 21 H 21 N2[M+H] + :301.1699,Found:301.1696.

[0069] In summary, the structural formula of the target product of this embodiment is as follows:

[0070] Embodiment 2:

[0071] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0072] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 89%).

[0073] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are as follows Figure 3 As shown and Figure 4 As shown, the spectrum analysis data is as follows:

[0074] 1 H NMR (400MHz, CDCl3) δ8.42–8.38(m,1H),8.22(d,J=8.7Hz,1H),7.96(dd,J=7.9,1.5Hz,1H),7.52–7.47(m,1H),7.40–7.34( m,2H),7.18(d,J=8.8Hz,2H),3.29–3.21(m,1H),2.70(s,3H),2.09(d,J=15.2Hz,2H),1.98–1.82(m,5H),1.60–1.39(m,3H).

[0075] 13 C NMR (100MHz, CDCl3) δ162.3,136.2,132.7,131.9,130.1,129.8,129.0,128.7, 127.4,124.0,123.8,122.4,114.5,112.1,97.4,43.2,31.2,26.6,26.1,19.0.

[0076] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0077] IR(KBr) Vmax :2925,2853,2361,1804,1533,1454,1400,1316,1208,746cm -1 .

[0078] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0079] HRMS (APCI) calculation for C 22 H 23 N2,[M+H] + :315.1856,Found:315.1854.

[0080] In summary, the structural formula of the target product of this embodiment is as follows:

[0081] Embodiment 3:

[0082] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0083] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 5:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 90%).

[0084] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are as follows Figure 5 As shown and Figure 6 As shown, the spectrum analysis data is as follows:

[0085] 1 H NMR (400MHz, CDCl3) δ8.39–8.37(m,1H),8.32(d,J=9.2Hz,1H),8.02–8.00(m,1H),7.54(t,J=8.4Hz,1H),7.41(t,J=8.0Hz,1H),7.3 1(d,J=2.8Hz,1H),7.18–7.14(m,2H),3.95(s,3H),3.28–3.21(m,1H),2.13(d,J=13.2Hz,2H),2.02–1.86(m,5H),1.62–1.43(m,3H).

[0086] 13 C NMR (100MHz, CDCl3) δ161.8,155.5,136.0,130.0,129.9,129.8,129.6,128.1, 127.4,123.6,115.5,114.9,114.1,102.2,98.5,55.5,43.3,31.2,26.6,26.1.

[0087] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0088] IR(KBr) Vmax :2919,2850,2359,1618,1531,1456,1214,1031,832,744cm -1 .

[0089] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0090] HRMS (APCI) calculation for C 22 H 23 N2O,[M+H] + :331.1805,Found:331.1803.

[0091] In summary, the structural formula of the target product of this embodiment is as follows:

[0092] Embodiment 4:

[0093] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0094] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 5:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 72%).

[0095] The decomposition data of the hydrogen spectrum and carbon spectrum of the target product of this embodiment are as follows:

[0096] 1 H NMR (400MHz, CDCl3) δ8.36(d,J=8.0Hz,1H),8.00–7.97(m,1H),7.87–7.83(m,2H),7.5–7.53(m,1H),7.41(t,J=7.6Hz,1H),7.18(s,1H),7. 14(dd,J=8.8,2.0Hz,1H),4.03(s,3H),3.26–3.18(m,1H),2.10(d,J=13.6Hz,2H),2.00–1.96(m,2H),1.93–1.84(m,3H),1.60–1.42(m,3H).

[0097] 13 C NMR (100MHz, CDCl3) δ162.5,157.5,136.3,133.5,130.1,129.8,128.8,127.1 ,123.8,123.4,123.1,114.2,113.1,99.3,97.7,55.9,43.3,31.2,26.6,26.1

[0098] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0099] IR(KBr) Vmax :2928,2852,2361,1604,1531,1492,1443,1260,1221,744cm -1 .

[0100] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0101] HRMS (APCI) calculation for C 22 H 23 N2O,[M+H] + :331.1805,Found:331.1801.

[0102] In summary, the structural formula of the target product of this embodiment is as follows:

[0103] Embodiment 5:

[0104] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0105] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 88%).

[0106] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are as follows Fig. 9 As shown and Fig.10 As shown, the spectrum analysis data is as follows:

[0107] 1 H NMR (400MHz, CDCl3) δ8.39(s,1H),8.28(d,J=8.4Hz,1H),7.99–7.97(m,1H),7.82(d,J=8.4Hz,1H),7.58–7.54(m,1H),7.44–7.40(m,1H),7. 37(dd,J=8.4,1.6Hz,1H),7.15(s,1H),3.25–3.17(m,1H),2.11(d,J=12.0Hz,2H),2.01–1.98(m,2H),1.95–1.85(m,3H),1.61–1.42(m,3H).

[0108] 13 C NMR (100MHz, CDCl3) δ162.2,136.1,132.7,130.0,129.7,129.5,129.5,127 .7,127.3,124.2,123.2,123.1,114.4,114.3,99.0,43.3,31.2,26.5,26.1.

[0109] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0110] IR(KBr) Vmax :2922,2359,1628,1472,1433,1396,1358,1085,814,743cm -1 .

[0111] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0112] HRMS (APCI) calculation for C 21 H 20 ClN2,[M+H] + :335.1310,Found:335.1307.

[0113] In summary, the structural formula of the target product of this embodiment is as follows:

[0114] Embodiment 6:

[0115] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0116] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 5:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 86%).

[0117] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are as follows Fig.11 As shown and Fig.12 As shown, the spectrum analysis data is as follows:

[0118] 1 H NMR (400MHz, CDCl3) δ8.69(s,1H),8.27(d,J=8.4Hz,1H),7.99(d,J=8.0Hz,1H),7.95(d,J=8.4Hz,1H),7.62–7.56(m,2H),7.46(t,J =7.6Hz,1H),7.19(s,1H),3.23–3.16(m,1H),2.08(d,J=12.4Hz,2H),1.97(d,J=13.2Hz,2H),1.91–1.81(m,3H),1.58–1.38(m,3H).

[0119] 13 C NMR (100MHz, CDCl3) δ161.9,136.2,131.7,131.6,131.4,130.6,129.2,128.5, 125.0,124.6,123.3,120.2,119.7,114.4,105.9,99.3,43.4,31.2,26.5,26.0.

[0120] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0121] IR(KBr)Vmax :2925,2851,2363,2223,1631,1438,1395,1351,814,745cm -1 .

[0122] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0123] HRMS (APCI) calculation for C 22 H 20 N3,[M+H] + :326.1652,Found:326.1649.

[0124] In summary, the structural formula of the target product of this embodiment is as follows:

[0125] Embodiment 7:

[0126] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0127] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 74%).

[0128] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are shown in Figure 13 and Fig.14 As shown, the spectrum analysis data is as follows:

[0129] 1H NMR(400MHz, CDCl3)δ8.49(s,1H),8.23(d,J=8.0Hz,1H),7.97–7.95(m,2H),7.56(t,J=7.4Hz,1H),7.42(t,J=7.4Hz,1H), 7.06(s,1H),3.16(t,J=11.6Hz,1H),2.07(d,J=12.4Hz,2H),1.96(d,J=12.4Hz,2H),1.90–1.84(m,3H),1.56–1.38(m,3H).

[0130] 13 C NMR (100MHz, CDCl3) δ161.9,136.0,131.0,130.4,130.2,129.1,128.3,127 .9,127.4,126.6,124.5,122.8,115.8,114.0,98.1,43.2,31.1,26.5,26.1.

[0131] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0132] IR(KBr) Vmax :2930,2851,2363,1615,1469,1443,1394,1362,1111,750cm -1 .

[0133] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0134] HRMS (APCI) calculation for C 22 H 23 N2,[M+H] + :369.0920,Found:369.0918.

[0135] In summary, the structural formula of the target product of this embodiment is as follows:

[0136] Embodiment 8:

[0137] A pyrrolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0138] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate three times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 5:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 62%).

[0139] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are shown in Figure 15 and Fig.16 As shown, the spectrum analysis data is as follows:

[0140] 1 H NMR (400MHz, CDCl3) δ9.90(s,1H),8.55(s,1H),8.44(d,J=8.4Hz,1H),8.05(d,J=7.2Hz,1H),7.83(d,J=4.8Hz,1H),7.66(t,J=7.4Hz,1H),7 .50(t,J=7.6Hz,1H),7.18(s,1H),3.30–3.22(m,1H),2.12(d,J=12.4Hz,2H),1.99(d,J=13.2Hz,2H),1.94–1.85(m,3H),1.60–1.41(m,3H).

[0141] 13 C NMR (100MHz, CDCl3) δ161.8,140.4,137.3,136.0,133.2,131.1,130.4,129.2,128.5,124.7,116.0,115.0,97.6,43.4,31.1,26.5,26.0.

[0142] The infrared test data of the pyrrolo[1,2-a]quinoxaline compounds of this embodiment are as follows:

[0143] IR(KBr) Vmax :2927,2852,2360,1631,1467,1441,1396,1352,821,749cm -1 .

[0144] The mass spectrum data of the pyrrolo[1,2-a]quinoxaline compounds of this example are as follows:

[0145] HRMS (APCI) calculation for C 20 H 20 N3,[M+H] + :302.1652,Found:302.1647.

[0146] In summary, the structural formula of the target product of this embodiment is as follows:

[0147] Embodiment 9:

[0148] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0149] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 91%).

[0150] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are shown in Figure 17 and Fig.18 As shown, the spectrum analysis data is as follows:

[0151] 1 H NMR (400MHz, CDCl3) δ8.41–8.39(m,1H),8.22(d,J=8.8Hz,1H),7.96(dd,J=7.6,1.2Hz,1H),7.52–7.47(m,1H),7.39–7.34(m,2H),7 .19–7.17(m,2H),3.29–3.21(m,1H),2.70(s,3H),2.09(d,J=15.2Hz,2H),1.98–1.94(m,2H),1.91–1.82(m,3H),1.60–1.39(m,3H).

[0152] 13 C NMR (100MHz, CDCl3) δ162.3,136.2,132.7,131.9,130.1,129.8,129.0,128.7, 127.4,124.0,123.8,122.4,114.5,112.1,97.4,43.2,31.2,26.6,26.1,19.0.

[0153] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0154] IR(KBr) Vmax :2920,2361,1613,1527,1495,1449,1422,1398,1303,747cm -1 .

[0155] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0156] HRMS (APCI) calculation for C 22 H 23 N2,[M+H] + :315.1856,Found:315.1853.

[0157] In summary, the structural formula of the target product of this embodiment is as follows:

[0158] Embodiment 10:

[0159] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0160] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 43%).

[0161] The hydrogen spectrum, carbon spectrum and fluorine spectrum of the target product of this embodiment are shown in Figure 19, Figure 20 and Figure Fig.21 As shown, the spectrum analysis data is as follows:

[0162] 1 H NMR (400MHz, CDCl3) δ8.31(d,J=8.4Hz,1H),8.20(s,1H),7.96(d,J=7.6Hz,1H),7.57(t,J=7.6Hz,1H),7.47(t,J=7.4Hz ,1H),7.28(s,1H),7.20–7.18(m,1H),3.29–3.23(m,1H),2.11(d,J=13.2Hz,2H),2.00–1.84(m,5H),1.60–1.42(m,3H).

[0163] 13 C NMR (100MHz, CDCl3) δ162.8, 159.6, 157.0, 132.8, 132.5 (d, J = 12.4Hz), 131.5 (d, J = 4.2Hz), 129.1, 128. 8,124.7,123.2,122.7,114.3,111.5(d,J=23.9Hz),110.5(d,J=4.0Hz),100.7,43.6,31.1,26.5,26.0.

[0164] 19 F NMR (376MHz, CDCl3) δ-118.79 (d, J=9.4Hz).

[0165] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0166] IR(KBr) Vmax:2919,2850,2356,1612,1538,1446,1399,1275,807,741cm -1 .

[0167] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0168] HRMS (APCI) calculation for C 21 H 19 ClFN2,[M+H] + :353.1215,Found:353.1212.

[0169] In summary, the structural formula of the target product of this embodiment is as follows:

[0170] Embodiment 11:

[0171] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0172] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate three times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 60%).

[0173] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are shown in 22 and Fig.23 As shown, the spectrum analysis data is as follows:

[0174] 1H NMR (400MHz, CDCl3) δ8.45(d,J=8.4Hz,1H),8.21(s,1H),7.95(d,J=7.6Hz,1H),7.78(s,1H),7.52(t,J=7.6Hz,1H),7.43(t,J=7. 4Hz,1H),7.20(s,1H),3.29–3.23(m,1H),2.50(s,3H),2.40(s,3H),2.15(d,J=12.4Hz,2H),2.03–1.87(m,5H),1.63–1.45(m,3H).

[0175] 13 C NMR (100MHz, CDCl3) δ161.2,136.5,134.3,132.6,132.3,130.2,129.2,128.9,12 7.9,123.3,122.3,122.1,115.2,114.5,98.4,43.2,31.2,26.6,26.1,20.4,19.2.

[0176] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0177] IR(KBr) Vmax :2926,2852,2358,1649,1529,1485,1449,1397,1278,738cm -1 .

[0178] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0179] HRMS (APCI) calculation for C 23 H 25 N2,[M+H] + :329.2012,Found:329.2010.

[0180] In summary, the structural formula of the target product of this embodiment is as follows:

[0181] Embodiment 12:

[0182] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0183] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 88%).

[0184] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are shown in 24 and Fig.25 As shown, the spectrum analysis data is as follows:

[0185] 1 H NMR(400MHz, CDCl3)δ8.48–8.45(m,2H),8.00(dd,J=15.2,8.0Hz,2H),7.59–7.53(m,2H),7.48–7.4 1(m,2H),7.22(s,1H),3.78–3.70(m,1H),2.31–2.17(m,4H),2.03–1.92(m,2H),1.88–1.78(m,2H).

[0186] 13 C NMR (100MHz, CDCl3) δ161.4,136.0,132.8,130.1,129.9,129.8,129.0,127.5,123.8,123.8,122.5,122.4,114.5,114.5,99.5,44.2,31.4,26.1.

[0187] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0188] IR(KBr) Vmax :2952,2867,2360,1612,1531,1474,1448,1401,1205,745cm -1 .

[0189] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0190] HRMS (APCI) calculation for C20 H 19 N2[M+H] + :287.1543,Found:287.1540.

[0191] In summary, the structural formula of the target product of this embodiment is as follows:

[0192] Embodiment 13:

[0193] An indolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0194] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate for 3 times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 50:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 73%).

[0195] The hydrogen spectrum and carbon spectrum of the target product of this embodiment are shown in 26 and Fig. 27 As shown, the spectrum analysis data is as follows:

[0196] 1 H NMR (400MHz, CDCl3) δ8.45(t,J=7.6Hz,2H),8.01–7.96(m,2H),7.56(dt,J=14.8,8.0Hz,2H),7.44(q,J=7. 6Hz,2H),7.19(s,1H),3.12(t,J=7.6Hz,2H),2.01–1.93(m,2H),1.63–1.53(m,2H),1.05(t,J=7.2Hz,3H).

[0197] 13C NMR (100MHz, CDCl3) δ156.0,135.9,132.8,130.2,129.7,129.5,129.0,127 .6,124.0,123.9,122.6,122.5,114.5,114.5,99.7,35.7,30.3,22.9,14.0.

[0198] The infrared test data of the indole [1,2-a] quinoxaline compounds of this embodiment are as follows:

[0199] IR(KBr) Vmax :2956,2361,1535,1473,1449,1398,1330,1294,1205,744cm -1 .

[0200] The mass spectrum data of the indole [1,2-a] quinoxaline compounds of this example are as follows:

[0201] HRMS (APCI) calculation for C 19 H 19 N2[M+H] + :275.1543,Found:275.1540.

[0202] In summary, the structural formula of the target product of this embodiment is as follows:

[0203] Embodiment 14:

[0204] A pyrrolo[1,2-a]quinoxaline compound, the preparation method of which comprises the following steps:

[0205] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate three times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 30:1, so as to obtain indolo[1,2-a]quinoxaline compounds (yield: 72%).

[0206] The hydrogen spectrum, carbon spectrum and fluorine spectrum of the target product of this embodiment are shown in 28, 29 and 30. Fig.30 As shown, the spectrum analysis data is as follows:

[0207] 1 H NMR (400MHz, CDCl3) δ8.27(s,1H),8.03(d,J=7.2Hz,1H),7.95(d,J=7.6Hz,1H),7.84(d,J=8.0Hz,1H),7.63–7.55(m,2H),7.23(t,J=8.2Hz,1H),7 .10(d,J=7.6Hz,1H),3.77–3.70(m,1H),2.15(d,J=12.4Hz,2H),1.94(d, J=13.2Hz,2H),1.88–1.78(m,3H),1.70–1.60(m,2H),1.43–1.32(m,1H).

[0208] 13 C NMR (100MHz, CDCl3) δ159.5,144.0,140.7,136.2,131.4(t,J=181.9Hz),130.3,128.8,128.4,127 .0,125.4,124.3,123.8,122.6,116.3,115.2,114.3,114.0,109.4,86.5,42.1,31.5,26.0,25.9.

[0209] 19 F NMR (376MHz, CDCl3) δ-49.27.

[0210] The infrared test data of the pyrrolo[1,2-a]quinoxaline compounds of this embodiment are as follows:

[0211] IR(KBr) Vmax :3461,3420,3351,3285,2922,1646,1350,1254,1122,746.

[0212] The mass spectrum data of the pyrrolo[1,2-a]quinoxaline compounds of this example are as follows:

[0213] HRMS(APCI):calcd for C 25 H 20 F2N3O2,[M+H] + :432.1518,Found:432.1516.

[0214] In summary, the structural formula of the target product of this embodiment is as follows:

[0215] Embodiment 15:

[0216] A phenanthridine compound, the preparation method of which comprises the following steps:

[0217] 0.1 mmol 0.5mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate three times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 30:1, and a phenanthridine compound (yield: 87%) was obtained.

[0218] The hydrogen spectrum, carbon spectrum and fluorine spectrum of the target product of this embodiment are shown in Figure 31 and Figure Fig.32 As shown, the spectrum analysis data is as follows:

[0219] 1 H NMR (400MHz, CDCl3) δ8.66(d,J=8.4Hz,1H),8.56(d,J=8.0Hz,1H),8.35(d,J=8.0Hz,1H),8.22(d,J=8.4Hz,1H),7.82(t,J=8.0Hz,1H),7.7 7–7.69(m,2H),7.66–7.62(m,1H),3.70–3.63(m,1H),2.15(d,J=10.8Hz,2H),2.07–1.97(m,4H),1.91(d,J=12.4Hz,1H),1.68–1.48(m,3H).

[0220] 13 C NMR (100MHz, CDCl3) δ165.2,143.8,132.9,129.9,129.8,128.3,127.0,126.0,125.5,124.6,123.3,122.5,121.7,41.9,32.2,26.8,26.3.

[0221] The infrared test data of the phenanthridine compounds of this embodiment are as follows:

[0222] IR(KBr) Vmax :3429,2926,2850,2357,1627,1388,1352,1120,752,622.

[0223] The mass spectrum data of the phenanthridine compound of this embodiment are as follows:

[0224] HRMS(APCI):calcd for C 19 H 20 N[M+H] + :262.1590,Found:262.1587.

[0225] In summary, the structural formula of the target product of this embodiment is as follows:

[0226] Embodiment 16:

[0227] A benzothiazole compound, the preparation method of which comprises the following steps:

[0228] 0.1 mmol 0.4mmol 0.002mmol of bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium di(hexafluorophosphate) salt (abbreviated as Ir[dF(CF3)ppy]2(dtbbpy)PF6) and 0.2mmol of DBU were dispersed in 2mL of dioxane, placed under visible light with a wavelength of 450nm-455nm, and reacted at room temperature for 12h under a stirring speed of 500rpm. The reaction solution was extracted with ethyl acetate three times, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure. The crude product obtained by the distillation under reduced pressure was purified by column chromatography. The eluent used in the column chromatography consisted of petroleum ether and ethyl acetate in a volume ratio of 30:1, and benzothiazole compounds (yield: 81%) were obtained.

[0229] The hydrogen spectrum, carbon spectrum and fluorine spectrum of the target product of this embodiment are shown in Figure 31 and Figure Fig.32 As shown, the spectrum analysis data is as follows:

[0230] 1H NMR (400MHz, CDCl3) δ7.97(d,J=8.0Hz,1H),7.84(d,J=8.0Hz,1H),7.46–7.42(m,1H),7.35–7.31(m,1H),3.15–3.07(m, 1H),2.22–2.19(m,2H),1.91–1.86(m,2H),1.79–1.74(m,1H),1.69–1.59(m,2H),1.50–1.39(m,2H),1.37–1.29(m,1H).

[0231] 13 C NMR (100MHz, CDCl3) δ177.6,153.0,134.5,125.8,124.5,122.5,121.5,43.4,33.4,26.0,25.7.

[0232] The infrared test data of the benzothiazole compound of this embodiment are as follows:

[0233] IR(KBr) Vmax :3483,2925,2352,1667,1520,1400,1328,1248,1084,747.

[0234] The mass spectrum data of the benzothiazole compound of this example are as follows:

[0235] HRMS(APCI):calcd for C 13 H 16 NS[M+H] + :218.0998,Found:218.0997.

[0236] In summary, the structural formula of the target product of this embodiment is as follows: Application testing:

[0237] The target product indole / pyrrolo[1,2-a]quinoxaline compound in Examples 4, 5, 6, 7 and 8 was prepared into 10 mL of a 10 -3 M of dichloromethane solution, then take 20ul of the target product solution and mix it with 2mL of dichloromethane, and then perform fluorescence test on the mixture to obtain the corresponding fluorescence emission spectrum of the target product as shown in the figure Fig.33 shown.

[0238] Depend on Fig.33It can be seen that the indole / pyrrolo[1,2-a]quinoxaline compounds in Examples 4, 5, 6, 7 and 8 all have excellent fluorescence properties, among which the products substituted with electron-donating MeO show a significant decrease in fluorescence intensity, while other substitution groups do not show a significant decrease in intensity, indicating that the electronic effect may affect the fluorescence absorption and fluorescence emission of the products.

[0239] After testing, the indole / pyrrolo[1,2-a]quinoxaline compounds in other embodiments also have excellent fluorescence properties. The preparation method of the present invention can be applied to the synthesis of fluorescent materials.

[0240] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a nitrogen heteroaromatic compound by photocatalytic synthesis, characterized in that: The following steps are involved: An isonitrile compound, an alkyl boronic acid reagent, a photosensitizer, an alkali reagent and a solvent are mixed and reacted under the irradiation of visible light to obtain an azaaromatic compound; The structural formula of the isonitrile compound is as follows: The structural formula of the alkyl boronic acid reagent is as follows: The structural formula of the nitrogen heteroaromatic compound is as follows: In the formula, R 1 is selected from one of hydrogen, alkyl, alkoxy, halogen, and cyano, Ar 1 and Ar 2 The substituents are independently selected from one or two of hydrogen, alkyl, alkoxy, halogen, and cyano, X is selected from one of C and N, and R is selected from an alkyl.

2. The preparation method according to claim 1, characterized in that: The structural formula of the isonitrile compound is as follows: The structural formula of the alkyl boronic acid reagent is as follows: The structural formula of the nitrogen heteroaromatic compound is as follows: In the formula, Ar 1 and Ar 2 The substituents are independently selected from one or two of H, Me, MeO, F, Cl, and CN, X is selected from one of C and N, and R is selected from one of cyclohexyl, cyclopentyl, and n-butyl.

3. The preparation method according to claim 1, characterized in that: The molar ratio of the isonitrile compound, the alkyl boronic acid reagent, the photosensitizer, and the alkaline reagent is 1:1-5:0.01-0.10:1-3; The concentration of the isonitrile compound is 50-100 mM.

4. The preparation method according to claim 1, characterized in that: The photosensitizer is at least one of 3,6-di-tert-butyl-9-mesityl-10-phenylacridine perchlorate, 2,4,5,6-tetra(carbazole-9-yl)-1,3-dicyanobenzene, 2',4',5',7'-tetrabromo-3',6'-dihydroxy-3H-spiro[isobenzofuran-1,9'-xanthene]-3-one, 2',4',5',7'-tetrabromo-3-oxo-3H-spiro[isobenzofuran-1,9'-xanthene]-3',6'-bis(phenol) disodium salt, and bis[2-(2,4-difluorophenyl)-5-trifluoromethylpyridine][2-2'-bi(4-tert-butylpyridine)]iridium hexafluorophosphate; The alkaline reagent is at least one of sodium carbonate, sodium acetate, potassium carbonate, cesium carbonate, potassium phosphate, DBU, and triethylamine; The solvent is at least one of tetrahydrofuran, acetonitrile, toluene, dichloroethane, methanol, dimethyl sulfoxide and dioxane.

5. The preparation method according to claim 1, characterized in that: The wavelength of the visible light is at least one of 380 to 525 nm.

6. The preparation method according to claim 1, characterized in that: The reaction temperature is 10°C to 80°C, and the reaction time is 8h to 18h.

7. The preparation method according to claim 1, characterized in that: The reaction is carried out under the condition of a stirring speed of 300 rpm to 700 rpm; After the reaction is completed, the reaction product is separated and purified.

8. The preparation method according to claim 7, characterized in that: The specific operation of separation and purification is: extracting the reaction solution with ethyl acetate, drying with anhydrous Na2SO4, and distilling under reduced pressure, and taking the crude product obtained by distillation under reduced pressure and purifying it by column chromatography; The eluent used in the column chromatography is composed of petroleum ether and ethyl acetate in a volume ratio of 3 to 50:

1.

9. Azaaromatic compounds prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the nitrogen heteroaromatic compound according to claim 9 as a luminescent material or in the preparation of an imaging agent, characterized in that: The structural formula of the nitrogen heteroaromatic compound is as follows: In the formula, Ar 1 and Ar 2 The substituents are independently selected from one or two of hydrogen, alkyl, alkoxy, halogen, and cyano, X is selected from one of C and N, and R is selected from an alkyl.

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