A method for electrochemical synthesis of 3-arylquinoxalinone compounds

Abstract

The present invention discloses an efficient C-H arylation reaction between quinoxalinone compounds and aryltriazenes induced by ionic liquids. Specifically, it relates to a method for the electrochemical synthesis of 3-arylquinoxalinone compounds, using aryltriazenes as stable arylation reagents and ionic liquids as promoters and electrolytes. Under mild, metal-free, and oxidant-free conditions, the method can synthesize a variety of 3-arylquinoxalinone compounds and arylated quinoxaline compounds in moderate to excellent yields. This scheme has the remarkable characteristics of simple operation, excellent functional group tolerance, high selectivity, strong product derivatization, and suitability for gram-scale continuous flow chemical synthesis.

Description

Technical Field

[0001] The present invention belongs to the field of preparing quinoxalinone compounds and discloses an electrochemical synthesis method for 3-arylquinoxalinone compounds. Aryl triazene is used as a convenient, stable and inexpensive aryl source to undergo an arylation reaction with a biologically active quinoxalinone compound under electrochemical conditions. Background Art

[0002] Substituted quinoxalinone compounds, especially arylated quinoxalinone compounds, are a class of molecules with a wide range of biological activities and are widely used in drugs, natural products, and materials. For example, the key skeletons of STK33 inhibitors, FXa coagulation inhibitors, and CFTR activators 4 all have 3-arylquinoxalinone structural scaffolds. Therefore, great progress has been made in the synthesis of these compounds. M.;Spoonamore,J.;Wei,J.;Guichard,B.;Ross,N.T.;Masson,K.;Silkworth,W.;Dandapani,S.;Palmer,M.;Scherer,C.A.;et al.A potent andselective quinoxalinone-based STK33 inhibitor does not show syntheticlethality in KRAS-dependent cells.[J].ACS Med.Chem.Lett.2012,3,1034-1038.,Willardsen,J.A.;Dudley,D.A.;Cody,W.L.;Chi,L.;McClanahan,T.B.;Mertz,T.E.;Potoczak,R.E.;Narasimhan,L.S.;Holland,D.R.;Rapundalo,S.T.;et al.Design,synthesis,and biological activity of potent and selective inhibitors of bloodcoagulation factor xa.[J].J.Med.Chem.2004,47,4089-4099.,Cil,O.;Phuan,P.-W.;Lee,S.;Tan,J.;Haggie,P.M.;Levin,M.H.;Sun,L.;Thiagarajah,J.R.;Ma,T.;Verkman,A.S.CFTR activator increases intestinal fluid secretion and normalizes stooloutput in a mouse model of constipation.[J].Cell.Mol.Gastroenterol.Hepatol.2016,2,317-327.)

[0003] In recent years, 3-arylquinoxalinones have been synthesized using various arylating agents, including arylboronic acids, arylhydrazines, diaryliodonium salts, arylamines, aryldiazonium salts, aryltriazenes, diarylformyl peroxides, and simple aromatic hydrocarbons. Although a wide range of arylating agents have been used for the direct arylation of quinoxalinones, their applications remain limited by shortcomings such as low reactivity, limited substrates, and poor stability. Therefore, the development of efficient arylating agents with excellent stability and reactivity remains an urgent need. In recent years, research on the synthesis of 3-aryl-substituted quinoxalinones has yielded a series of excellent results.

[0004] ( A.;Brion,JD;Alami,M.;Messaoudi,S.Assisted tandem palladium(II) / palladium(0)-catalyzed C-and N-arylations of quinoxalin-2(1H)-ones inwater.[J].Adv.Synth.Catal.2014,356,3821-3830.,Bao,H.;Lin,Z.;Jin,M.;Zhang,H.;Xu,J.;Chen,B.;Li,W.Visible-light-induced CH arylation of quinoxalin-2(1H)-ones in H2O.[J].Tetrahedron Lett.2021,66152841., A.;Brion,J.D.;Messaoudi,S.;Alami,M.Palladium(II)-catalyzed qxidativearylation of quinoxalin-2(1H)-ones with.arylboronicacids[J].Org.Lett.2013,15,5606-5069.,Tian,M.;Liu,S.;Bu,X.;Yu,J.;Yang,X.Covalent organic frameworks:asustainable photocatalyst towardvisible-light-accelerated C3 arylation and alkylation of quinoxalin-2(1H)-ones.[J].Chem.Eur.J.2020,26,369-373.,Paul,S.;Ha,J.H.;Park,G.E.;Lee,Y.R.Transition metal-free iodosobenzene-promoted direct oxidative 3-arylationof quinoxalin-2(1H)-ones with arylhydrazines.[J].Adv.Synth.Catal.2017,359,1515-1521.,Song,S.;Shi,X.;Zhu,Y.;Ren,Q.;Zhou,P.;Zhou,J.;Li,J.Electrochemicaloxidative C–H arylation of quinoxalin(on)es with arylhydrazinehydrochloridesunder mild conditions.[J].J.Org.Chem.2022,87,4764-4776.,Samanta,R.K.;Meher,P.;Murarka,S.Visible light photoredox-catalyzed direct C–H arylation ofquinoxalin-2(1H)-ones with diaryliodonium salts.[J].J.Org.Chem.2022,87,10947-10957.,Yin,K.;Zhang,R.Transition-metal-free direct C–H arylation ofquinoxalin-2(1H)-ones with diaryliodonium salts at room temperature.[J].Org.Lett.2017,19,1530-1533.,Yuan,J.;Liu,S.;Qu,L.Transition metal-free directC-3arylation of quinoxalin-2(1H)-ones with arylamines under mild conditions.[J].Adv.Synth.Catal.2017,359,4197-4207.,Jiang,Y.y.;Dou,G.y.;Zhang,L.s.;Xu,K.;Little,R.D.;Zeng,C.c.Electrochemical cross-coupling of C(sp. 2)-H witharyldiazonium salts via a paired electrolysis:an alternative to visible lightphotoredox-based approach.[J].Adv.Synth.Catal.2019,361,5170-5175.,Kwon,S.J.;Jung,H.I.;Kim,D.Y.Visible light photoredox-catalyzed arylation of quinoxalin-2(1H)-ones with aryldiazonium salts.[J].ChemistrySelect 2018,3,5824-5827.,Wang,P.;Yang,Z.;Wang,Z.;Xu,C.;Huang,L.;Wang,S.;Zhang,H.;Lei,A.Electrochemicalarylation of electron-deficient arenes through reductive activation.[J].Angew.Chem.Int.Ed.2019,58,15747-15751.,Wang,B.;Feng,Y.;Zhang,Y.;Wang,S.;Zhou,X.;Chen,Z.;Xia,Y.;Jin,W.;Iqbal,A.;Liu,C.;Zhang,Y.Photo-driven direct C-Harylation of quinoxalin-2(1H)-ones with aryltriazenes under catalyst-free andambient conditions.[J].Eur.J.Org.Chem.2023,26e202300044.,Xu,J.;Zhang,H.;Zhao,J.;Ni,Z.;Zhang,P.;Shi,B.-F.;Li,W.Photocatalyst-,metal-and additive-free,direct C–H arylation of quinoxalin-2(1H)-ones with aryl acyl peroxidesinduced by visible light.[J].Org.Chem.Front.2020,7,4031-4042.,Xie,L.-Y.;Peng,S.;Yang,L.-H.;Peng, C.; Lin, Y.-W.; Yu, Chem.2021,23,374-378.,Paul,S.;Khanal,HD;Clinton,CD;Kim,SH;Lee,YRPd(TFA)2-catalyzed direct arylation ofquinoxalinones with arenes.[J].Org.Chem.Front.2019,6,231-235.).

[0005] Aryl triazenes are commonly used as alternatives to aryl diazonium salts in arylation reactions and are widely employed to construct C-C bonds and carbon-heteroatom bonds. In the presence of Lewis acids (BF3·Et2O, AgOAc, CuCl2, Cu(OAc)2, etc.) or Brønsted acids (HBF4, TFA, HCl, HBr, etc.), aryl cations are generated or, through further single-electron reduction, aryl radicals are obtained. In this paper, we report the generation of aryl radicals from aryl triazenes catalyzed by bifunctional ionic liquids, enabling the construction of triarylquinoxalinones under mild conditions. This reaction utilizes readily available starting materials, a broad substrate range, and requires no additional ligand. Summary of the Invention

[0006] The present invention aims to provide a method for synthesizing triarylquinoxalinones using an aryltriazene as a simple and readily available arylation reagent, using an ionic liquid as an electrolyte and promoter, without the need for additional acid. The method utilizes ionic liquids to promote the arylation of quinoxalinones, resulting in the synthesis of triarylquinoxalinones. The advantages of the present invention include: ionic liquid promotion, readily available and inexpensive raw materials, a wide range of substrates, the ability to prepare large quantities of quinoxalinones, the absence of external acid, and mild reaction conditions. To achieve the above objectives, the present invention provides the following technical solutions:

[0007] Under ionic liquid-promoting conditions, quinoxalinone compound 1 reacts with aryltriazene 2 under certain conditions (Scheme 1). After the reaction, the products are isolated and characterized using conventional separation and purification methods to obtain the corresponding 3-arylquinoxalinone compound and arylated quinoxaline compound 3.

[0008] The structural formula 3 of the 3-arylquinoxalinone compound and the arylated quinoxaline compound is as follows:

[0009]

[0010] R1 is one or more of H, methyl, chlorine or bromine, and the number of these is 1-3; R2 is one or more of H, methyl, methoxy, ethyl, tert-butyl, n-dodecyl, halogen, C2-C6 ester group, benzyl, 4-methyldiphenyl ether and 4-methoxydiphenyl ether substituents, and naphthalene ring, and halogen is one or more of fluorine, chlorine, bromine, and iodine; R3 is one or more of methyl, H, ethyl, propyl, allyl, propargyl, cyclopropyl, cyclohexyl, C2-C6 ester group, and benzoyl ; "O / R4" represents one or more of "O or R4", R4 is one or more of methyl, amino, and thiol; the dotted line inside the benzene ring (two dashed and solid lines) indicates that under different substituent conditions, that position can be a double bond or a single bond, such as R4 is a methyl, amino, and thiol are single bonds (the corresponding dashed and solid lines between O / R4 and the benzene ring represent that position can be a double bond or a single bond, in this case this position is a single bond), when O / R4 is a carbonyl O, it is a single bond, and that position is a double bond connected to the oxygen group.

[0011] A quinoxalinone compound 1 and an aryl triazene 2 are reacted in the presence of a bifunctional ionic liquid; after the reaction, the products are separated to obtain 3 arylquinoxalinone compounds and an arylated quinoxaline compound 3.

[0012]

[0013] wherein the substituents R1, R2, R3 and R4 are the same as described above;

[0014] When N-methylquinoxalinone 1 reacts with aryltriazene 2, the solvent is one or more of methanol, ethanol, acetonitrile, N,N-dimethylformamide, trifluoroethanol, dimethyl sulfoxide, dimethyl sulfoxide, and acetonitrile (volume ratio of 1:0.5-2). The best effect is achieved when dimethyl sulfoxide is the reaction solvent. The amount of solvent added is 3-5 mL of solvent per 0.2 mmol of N-methylquinoxalinone 1.

[0015] When N-methylquinoxalinone 1 reacts with aryltriazene 2, either one or both of 1,3-bis(butylsulfonic acid imidazolate) ionic liquid IL1 and 1-ethyl-3-butylsulfonic acid imidazolate ionic liquid IL2 are added to the reaction, serving as electrolytes and accelerators. The amount of ionic liquid added is 0.3-0.4 mmol per 0.2 mmol of N-methylquinoxalinone 1. The preparation method according to claim 1 is characterized in that the reaction current is either one or both of 4-7 mA, with the optimal reaction current being 6-8 mA.

[0016] When N-methylquinoxalinone 1 reacts with aryl triazene 2, the molar ratio of N-methylquinoxalinone 1 to aryl triazene 2 is in the range of 1:2.5-1, and the optimal ratio is 1:2-3. When quinoxalinone 1 reacts with aryl triazene 2, the reaction time is 2-7 h, and the optimal reaction time is 3-5 h. The synthesis reaction of the present invention comprises the following steps: Synthesis of p-methyltriazene 2a:

[0017]

[0018] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88(15): 11056-11068.), p-methylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 1 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 min, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 min. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in the above reaction formula 2a.

[0019] Synthesis of phenyltriazene 2b:

[0020]

[0021] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), aniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in the above reaction formula 2b.

[0022] Synthesis of o-methyltriazene 2c:

[0023]

[0024] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), o-methylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2c in the above reaction formula.

[0025] Synthesis of m-methyltriazene 2d:

[0026]

[0027] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-methylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2d in the above reaction formula.

[0028] Synthesis of p-ethyltriazene 2e:

[0029]

[0030] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-ethylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2e in the above reaction formula.

[0031] Synthesis of tert-butyltriazene 2f:

[0032]

[0033] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88(15): 11056-11068.), p-tert-butylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2f in the above reaction formula.

[0034] Synthesis of 2g of 4-dodecyltriazene:

[0035]

[0036] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 4-dodecylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2g in the above reaction formula.

[0037] Synthesis of p-methoxytriazene 2h:

[0038]

[0039] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88(15): 11056-11068.), p-Anisidine (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was continued to be stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was continued to be stirred at room temperature for about 30 minutes. After the completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2h in the above reaction formula.

[0040] Synthesis of 4-fluorotriazene 2i:

[0041]

[0042] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-Fluoroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2i in the above reaction formula.

[0043] Synthesis of p-chlorotriazene 2j:

[0044]

[0045] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-chloroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 min, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 min. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2j in the above reaction formula.

[0046] Synthesis of p-bromotriazene 2k:

[0047]

[0048] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-bromoaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2k in the above reaction formula.

[0049] Synthesis of p-iodotriazene 2l:

[0050]

[0051] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-iodoaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 min, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 min. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 21 in the above reaction formula.

[0052] Synthesis of m-fluorotriazene 2m:

[0053]

[0054] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-fluoroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2m in the above reaction formula.

[0055] Synthesis of m-chlorotriazene 2n:

[0056]

[0057] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-chloroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2n in the above reaction formula.

[0058] Synthesis of m-bromotriazene 2o:

[0059]

[0060] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-bromoaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The resulting diazonium salt solution was stirred in an ice bath for approximately 15 minutes, then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and 10 mmol of tetrahydropyrrole. The reaction mixture was stirred at room temperature for approximately 30 minutes. After completion of the reaction, the product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in the above reaction formula (2o). Synthesis of Methyl Benzoate Triazene 2p

[0061]

[0062] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), methyl 4-aminobenzoate (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2p in the above reaction formula.

[0063] Synthesis of 3-benzyltriazene 2q:

[0064]

[0065] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-benzylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2q in the above reaction formula.

[0066] Synthesis of 4-(4-methoxyphenoxy)triazene 2r:

[0067]

[0068] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 4-(4-methoxyphenoxy)aniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2r in the above reaction formula.

[0069] Synthesis of 4-methyldiphenyl ether triazene 2s:

[0070]

[0071] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 4-amino-4'-methyldiphenyl ether (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2s in the above reaction formula.

[0072] Synthesis of naphthalenetriazene 2t:

[0073]

[0074] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 2-naphthylamine (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2t in the above reaction formula.

[0075] Synthesis of N-methylquinoxalinone 1a:

[0076]

[0077] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), an ethanol suspension (20 mL) of o-aryl diamine (5 mmol) was added to ethyl glyoxylate (5.5 mmol). The reaction solvent was stirred and heated to reflux for 16 h. After the reaction was completed (TLC monitoring), the precipitate was filtered, washed with ethanol at -3-1°C, and finally dried to obtain quinoxalinone. Quinoxalinone (5 mmol) and DMF (15 mL) were then added to a 100 mL round-bottom flask with a stirring bar, followed by potassium carbonate (828 mg, 6 mmol) and then iodomethane (8 mmol). The reaction mixture was stirred at room temperature for 12 hours, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4 and dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate) (15:1-3:1) gradient elution. Its structure was confirmed by nuclear magnetic resonance to be that shown in reaction formula 1a above.

[0078] Synthesis of N-ethylquinoxalinone 1c:

[0079]

[0080] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then ethyl iodide (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed it to be N-ethylquinoxalinone 1c, the product shown in the above reaction formula.

[0081] Synthesis of N-propylquinoxalinone 1d:

[0082]

[0083] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then 1-iodopropane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added to anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed that it was N-propylquinoxalinone 1d, the product shown in the above reaction formula.

[0084] Synthesis of N-allylquinoxalinone 1e:

[0085]

[0086] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then acryloyl iodide (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain the desired product, which was confirmed by nuclear magnetic resonance to be the product shown in the above reaction formula, N-allylquinoxalinone 1e.

[0087] Synthesis of N-propargylquinoxalinone 1f:

[0088]

[0089] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction solvent was stirred and heated under reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol) and then 3-chloropropyne (8 mmol) dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added to anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain the desired product, which was confirmed by nuclear magnetic resonance to be the product shown in the above reaction formula, N-propargylquinoxalinone 1f.

[0090] Synthesis of 1-(cyclopropylmethyl)quinoxalinone 1g:

[0091]

[0092] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction solvent was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then (iodomethyl)cyclopropane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4 and dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain 1 g of the desired product, which was confirmed by nuclear magnetic resonance to be 1-(cyclopropylmethyl)quinoxalinone as shown in the above reaction formula.

[0093] Synthesis of 1-(cyclohexylmethyl)quinoxalinone 1h:

[0094]

[0095] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then (iodomethyl)cyclohexane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4 and dried, filtered, and evaporated. The desired target product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance confirmed that it was the product shown in the above reaction formula, 1-(cyclohexylmethyl)quinoxalinone 1h.

[0096] Synthesis of ethyl 2-(2-oxoquinoxalin-1(2-hydrogen)-yl)acetate 1i:

[0097]

[0098] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then ethyl chloroacetate (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) using gradient elution. Nuclear magnetic resonance (NMR) confirmed the product to be ethyl 2-(2-oxoquinoxaline-1(2-hydrogen)-yl)acetate 1i, as shown in the above reaction formula.

[0099] Synthesis of 1-(2-oxo-2-phenylethyl)quinoxalin-2(1H)-one 1j:

[0100]

[0101] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then phenacyl chloride (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance (NMR) confirmed that it was the product 1-(2-oxo-2-phenylethyl)quinoxaline-2(1-hydro)-one 1j shown in the above reaction formula.

[0102] Synthesis of 6-bromo-1-methylquinoxalinone 1k:

[0103]

[0104] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of 4-bromobenzene-1,2-diamine (5 mmol) in ethanol (20 mL) was mixed with ethyl glyoxylate (5.5 mmol). The reaction was stirred and heated under reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then iodomethane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 hours, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance (NMR) confirmed it to be 6-bromo-1-methylquinoxalinone 1k, the product shown in the above reaction formula.

[0105] Synthesis of 1,6,7-trimethylquinoxalinone 1l:

[0106]

[0107] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of 4,5-dimethylbenzene-1,2-diamine (5 mmol) in ethanol (20 mL) was mixed with ethyl glyoxylate (5.5 mmol). The mixture was stirred and heated under reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then iodomethane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 hours, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance (NMR) confirmed the product, 1,6,7-trimethylquinoxalinone 11, as shown in the above reaction formula.

[0108] Synthesis of 6,7-dichloro-1-methylquinoxalinone 1m:

[0109]

[0110] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of 4,5-dichlorobenzene-1,2-diamine (5 mmol) in ethanol (20 mL) was mixed with ethyl glyoxylate (5.5 mmol). The mixture was stirred and heated to reflux for 16 h. After the reaction was completed (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then iodomethane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 hours, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed the product as 1m 6,7-dichloro-1-methylquinoxalinone as shown in the above reaction formula.

[0111] Synthesis of 1,3-Bisbutylsulfonic Acid Imidazolium Ionic Liquid IL1

[0112]

[0113] The synthesis process of 1,3-bis(butylsulfonic acid imidazolium) acidic ionic liquid is as follows. It is carried out by reacting 1,4-butane sultone (0.3 mol) with (0.6 mol) N-(trimethylsilyl) imidazole at 80°C for 24 hours, and then acidifying the resulting zwitterion with 18.4 mol / L concentrated sulfuric acid at 80°C for 72 hours. After the reaction is completed, the entire reaction mixture is dissolved in 20 mL of distilled water and repeatedly washed three times with diethyl ether (15 mL), and then dried under vacuum (100°C) for 2 hours to obtain the desired ionic liquid 1,3-bis(butylsulfonic acid imidazolium) acidic ionic liquid. The product is confirmed to be the product shown in the above reaction formula by nuclear magnetic resonance and high-resolution mass spectrometry.

[0114] Synthesis of 1-Ethyl-3-butanesulfonic Acid Imidazolium Ionic Liquid IL2

[0115]

[0116] The synthesis process of 1-ethyl-3-butanesulfonic acid imidazolium acidic ionic liquid is as follows. It is a process of reacting 1,4-butane sultone (0.3 mol) with (0.3 mol) 1-ethylimidazole at 80°C for 24 hours, followed by hydrochloric acidization of the resulting 1-ethyl-3-butanesulfonic acid imidazolium acid at 80°C for 72 hours with 18.4 mol / L concentrated sulfuric acid. After the reaction is completed, the entire reaction mixture is dissolved in 20 mL of distilled water, washed three times with diethyl ether (15 mL), and then dried under vacuum (80°C) for 3 hours to obtain the desired ionic liquid 1-ethyl-3-butanesulfonic acid imidazolium acidic ionic liquid. The product is confirmed to be the product shown in the above reaction formula by nuclear magnetic resonance and high-resolution mass spectrometry.

[0117] The present invention provides the beneficial effects of an ionic liquid-induced efficient C-H alkylation reaction of quinoxalinone compounds with aryltriazenes. Specifically, it relates to an electrochemical synthesis method for 3-arylquinoxalinone compounds, using aryltriazenes as stable arylation reagents and ionic liquids as promoters and electrolytes. Under mild, metal-free, and oxidant-free conditions, a variety of 3-arylquinoxalinone compounds and arylated quinoxaline compounds are produced in moderate to excellent yields. This scheme exhibits significant advantages, including ease of operation, excellent functional group tolerance, high selectivity, strong product derivatization, and suitability for gram-scale continuous flow chemical synthesis.

[0118] This invention uses stable, easily prepared, and multi-reactive aryl triazenes as arylation reagents, employs ionic liquids as electrolytes and promoters, and uses DMSO as solvent to achieve an electrochemical cross-coupling reaction between aryl triazenes and quinoxalinone at room temperature. Advantages of this invention include ease of scale-up, simple operation, mild reaction conditions, a wide range of substrate applications, strong scalability, and readily available raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] Figure 1 The following are the hydrogen and carbon nuclear magnetic spectra of the nuclear magnetic resonance instrument of Example 1.

[0120] Figure 2 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 2.

[0121] Figure 3 The following are the hydrogen and carbon nuclear magnetic spectra of the nuclear magnetic resonance instrument of Example 3.

[0122] Figure 4 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 4.

[0123] Figure 5 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 4.

[0124] Figure 6 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 6.

[0125] Figure 7 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 7.

[0126] Figure 8 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 8.

[0127] Figure 9 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 9.

[0128] Figure 10 The following are the hydrogen and carbon nuclear magnetic resonance spectra of Example 10.

[0129] Figure 11 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 11.

[0130] Figure 12 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 12.

[0131] Figure 13 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 13.

[0132] Figure 14 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 14.

[0133] Figure 15 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 15.

[0134] Figure 16 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 16.

[0135] Figure 17 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 17.

[0136] Figure 18 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 18.

[0137] Figure 19 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 19.

[0138] Figure 20 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 20.

[0139] Figure 21 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 21.

[0140] Figure 22These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 22.

[0141] Figure 23 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 23.

[0142] Figure 24 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 24.

[0143] Figure 25 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 25.

[0144] Figure 26 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 26.

[0145] Figure 27 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 27.

[0146] Figure 28 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 28.

[0147] Figure 29 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 29.

[0148] Figure 30 These are the hydrogen and carbon nuclear magnetic spectra of the nuclear magnetic resonance instrument of Example 30.

[0149] Figure 31 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 31.

[0150] Figure 32 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 32.

[0151] Figure 33 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 33.

[0152] Figure 34 The nuclear magnetic resonance hydrogen spectrum and carbon spectrum of Example 34 are

[0153] Figure 35 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 35.

[0154] Figure 36 These are the hydrogen and carbon nuclear magnetic resonance spectra of Example 36. DETAILED DESCRIPTION

[0155] The present invention will be further described in detail with reference to the following specific examples, and the protection content of the present invention is not limited to the following examples. Without departing from the spirit and scope of the inventive concept, changes and advantages that can be imagined by those skilled in the art are included in the present invention, and are protected by the appended claims. The process, conditions, reagents, experimental methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are common knowledge and common common sense in the art, and the present invention has no special restrictions. The products of the embodiments include known compounds, and the data given in the following examples include specific operations and reaction conditions and products. The purity of the product is identified by nuclear magnetic resonance and high-resolution mass spectrometry.

[0156] Synthesis of p-methyltriazene 2a:

[0157]

[0158] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-methylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in the above reaction formula 2a.

[0159] Synthesis of phenyltriazene 2b:

[0160]

[0161] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), aniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2b in the above reaction formula.

[0162] Synthesis of o-methyltriazene 2c:

[0163]

[0164] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), o-methylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2c in the above reaction formula.

[0165] Synthesis of m-methyltriazene 2d:

[0166]

[0167] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-methylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2d in the above reaction formula.

[0168] Synthesis of p-ethyltriazene 2e:

[0169]

[0170] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-ethylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2e in the above reaction formula.

[0171] Synthesis of tert-butyltriazene 2f:

[0172]

[0173] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88(15): 11056-11068.), p-tert-butylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2f in the above reaction formula.

[0174] Synthesis of 2g of 4-dodecyltriazene:

[0175]

[0176] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 4-dodecylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2g in the above reaction formula.

[0177] Synthesis of p-methoxytriazene 2h:

[0178]

[0179] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88(15): 11056-11068.), p-Anisidine (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was continued to be stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was continued to be stirred at room temperature for about 30 minutes. After the completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2h in the above reaction formula.

[0180] Synthesis of 4-fluorotriazene 2i:

[0181]

[0182] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-Fluoroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2i in the above reaction formula.

[0183] Synthesis of p-chlorotriazene 2j:

[0184]

[0185] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-chloroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 min, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 min. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2j in the above reaction formula.

[0186] Synthesis of p-bromotriazene 2k:

[0187]

[0188] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-bromoaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2k in the above reaction formula.

[0189] Synthesis of p-iodotriazene 2l:

[0190]

[0191] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-iodoaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 min, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 min. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 21 in the above reaction formula.

[0192] Synthesis of m-fluorotriazene 2m:

[0193]

[0194] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-fluoroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be as shown in 2m in the above reaction formula.

[0195] Synthesis of m-chlorotriazene 2n:

[0196]

[0197] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions[J]. J. Org. Chem., 2023, 88(15): 11056-11068.), m-chloroaniline (10 mmol) was added to a 100 mL round-bottom flask, and then concentrated hydrochloric acid (2 mL) with a molar concentration of 12 mol / L was slowly added to the above aniline at 0°C, and an aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of potassium carbonate (1.2 mol / L) aqueous solution and tetrahydropyrrole (10 mmol). The reaction mixture was stirred at room temperature for about 30 minutes. After the reaction was completed by thin-layer chromatography, the obtained product was recrystallized with ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be the structure shown in 2n in the above reaction formula.

[0198] Synthesis of m-bromotriazene 2o:

[0199]

[0200] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), m-bromoaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The resulting diazonium salt solution was stirred in an ice bath for approximately 15 minutes, then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and 10 mmol of tetrahydropyrrole. The reaction mixture was stirred at room temperature for approximately 30 minutes. After completion of the reaction, the product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in the above reaction formula (2o). Synthesis of Methyl Benzoate Triazene 2p

[0201]

[0202] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), methyl 4-aminobenzoate (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2p in the above reaction formula.

[0203] Synthesis of m-benzyltriazene 2q:

[0204]

[0205] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), p-benzylaniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2q in the above reaction formula.

[0206] Synthesis of 4-(4-methoxyphenoxy)triazene 2r:

[0207]

[0208] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 4-(4-methoxyphenoxy)aniline (10 mmol) was added to a 100 mL round-bottom flask, and then 12 mol / L concentrated hydrochloric acid (2 mL) was slowly added to the above aniline at 0 ° C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2r in the above reaction formula.

[0209] Synthesis of 4-methyldiphenyl ether triazene 2s:

[0210]

[0211] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 4-amino-4'-methyldiphenyl ether (10 mmol) was added to a 100 mL round-bottom flask, and then concentrated hydrochloric acid (2 mL) with a molar concentration of 12 mol / L was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of an aqueous solution of potassium carbonate (1.2 mol / L) and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or separated and purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2s in the above reaction formula.

[0212] Synthesis of naphthalenetriazene 2t:

[0213]

[0214] According to previous literature reports (Gao J, Song Q, Zhang L, et al. Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions [J]. J. Org. Chem., 2023, 88 (15): 11056-11068.), 2-naphthylamine (10 mmol) was added to a 100 mL round-bottom flask, and then concentrated hydrochloric acid (2 mL) with a molar concentration of 12 mol / L was slowly added to the above aniline at 0°C. An aqueous solution (5 mL) of sodium nitrite (11 mmol) was prepared and added dropwise to the hydrochloric acid solution of aniline. The obtained diazonium salt solution was further stirred in an ice bath for about 15 minutes, and then added all at once to a 0-2°C solution containing 10 mL of a 1.2 mol / L aqueous solution of potassium carbonate and tetrahydropyrrole (10 mmol). The reaction mixture was further stirred at room temperature for about 30 minutes. After completion of the reaction monitored by thin-layer chromatography, the obtained product was recrystallized from ethanol or purified by column chromatography. Its structure was confirmed by nuclear magnetic resonance to be that shown in 2t in the above reaction formula.

[0215] Synthesis of N-methylquinoxalinone 1a:

[0216]

[0217] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then methyl iodide (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain the desired product, which was confirmed by nuclear magnetic resonance to be N-methylquinoxalinone 1a as shown in the above reaction formula.

[0218] Synthesis of N-ethylquinoxalinone 1c:

[0219]

[0220] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then ethyl iodide (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed it to be N-ethylquinoxalinone 1c, the product shown in the above reaction formula.

[0221] Synthesis of N-propylquinoxalinone 1d:

[0222]

[0223] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then 1-iodopropane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added to anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed that it was N-propylquinoxalinone 1d, the product shown in the above reaction formula.

[0224] Synthesis of N-allylquinoxalinone 1e:

[0225]

[0226] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then acryloyl iodide (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain the desired product, which was confirmed by nuclear magnetic resonance to be the product shown in the above reaction formula, N-allylquinoxalinone 1e.

[0227] Synthesis of N-propargylquinoxalinone 1f:

[0228]

[0229] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction solvent was stirred and heated under reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol) and then 3-chloropropyne (8 mmol) dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added to anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain the desired product, which was confirmed by nuclear magnetic resonance to be the product shown in the above reaction formula, N-propargylquinoxalinone 1f.

[0230] Synthesis of 1-(cyclopropylmethyl)quinoxalinone 1g:

[0231]

[0232] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction solvent was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then (iodomethyl)cyclopropane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4 and dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution to obtain 1 g of the desired product, which was confirmed by nuclear magnetic resonance to be 1-(cyclopropylmethyl)quinoxalinone as shown in the above reaction formula.

[0233]

[0234] Synthesis of 1-(cyclohexylmethyl)quinoxalinone 1h:

[0235] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then (iodomethyl)cyclohexane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4 and dried, filtered, and evaporated. The desired target product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance confirmed that it was the product shown in the above reaction formula, 1-(cyclohexylmethyl)quinoxalinone 1h.

[0236] Synthesis of ethyl 2-(2-oxoquinoxalin-1(2-hydrogen)-yl)acetate 1i:

[0237]

[0238] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then ethyl chloroacetate (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) using gradient elution. Nuclear magnetic resonance (NMR) confirmed the product to be ethyl 2-(2-oxoquinoxaline-1(2-hydrogen)-yl)acetate 1i, as shown in the above reaction formula.

[0239] Synthesis of 1-(2-oxo-2-phenylethyl)quinoxalin-2(1H)-one 1j:

[0240]

[0241] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions [J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of o-aryl diamine (5 mmol) in ethanol (20 mL) and ethyl glyoxylate (5.5 mmol) were mixed. The reaction was stirred and heated to reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then phenacyl chloride (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was added with anhydrous Na2SO4, dried, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance (NMR) confirmed that it was the product 1-(2-oxo-2-phenylethyl)quinoxaline-2(1-hydro)-one 1j shown in the above reaction formula.

[0242] Synthesis of 6-bromo-1-methylquinoxalinone 1k:

[0243]

[0244] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of 4-bromobenzene-1,2-diamine (5 mmol) in ethanol (20 mL) was mixed with ethyl glyoxylate (5.5 mmol). The reaction was stirred and heated under reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then iodomethane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 h, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If no separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed that it was the product shown in the above reaction formula, 6-bromo-1-methylquinoxalinone 1k.

[0245] Synthesis of 1,6,7-trimethylquinoxalinone 1l:

[0246]

[0247] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of 4,5-dimethylbenzene-1,2-diamine (5 mmol) in ethanol (20 mL) was mixed with ethyl glyoxylate (5.5 mmol). The mixture was stirred and heated under reflux for 16 h. After completion of the reaction (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with the quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then iodomethane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 hours, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. Nuclear magnetic resonance (NMR) confirmed the product, 1,6,7-trimethylquinoxalinone 11, as shown in the above reaction formula.

[0248] Synthesis of 6,7-dichloro-1-methylquinoxalinone 1m:

[0249]

[0250] According to previous literature reports (Wang, B.; Feng, Y, et al. Photo-Driven Direct C-HArylation of Quinoxalin-2(1H)-Ones with Aryltriazenes under Catalyst-Free and Ambient Conditions[J]. Eur. J. Org. Chem., 2023, 26, e202300044.), a suspension of 4,5-dichlorobenzene-1,2-diamine (5 mmol) in ethanol (20 mL) was mixed with ethyl glyoxylate (5.5 mmol). The mixture was stirred and heated to reflux for 16 h. After the reaction was completed (TLC monitoring), the precipitate was filtered, washed with ethanol at -3 to 1°C, and finally dried to obtain the quinoxalinone. A 100 mL round-bottom flask with a stir bar was then charged with quinoxalinone (5 mmol) and DMF (15 mL), followed by potassium carbonate (828 mg, 6 mmol), and then iodomethane (8 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 12 hours, poured into 30 mL of water, and extracted with 30 mL of ethyl acetate. If any separation occurred, 10 mL of saturated brine was added. The organic phase (ethyl acetate phase) was dried over anhydrous Na2SO4, filtered, and evaporated. The desired product was purified by column chromatography (petroleum ether / ethyl acetate = 15:1-3:1, volume ratio, linear gradient elution) and gradient elution. NMR confirmed the product as 1m 6,7-dichloro-1-methylquinoxalinone as shown in the above reaction formula.

[0251] Synthesis of 1,3-Bisbutylsulfonic Acid Imidazolium Ionic Liquid IL1

[0252]

[0253] The synthesis process of 1,3-bis(butylsulfonic acid imidazolium) acidic ionic liquid is as follows. It is carried out by reacting 1,4-butane sultone (0.3 mol) with (0.6 mol) N-(trimethylsilyl) imidazole at 80°C for 24 hours, and then acidifying the resulting zwitterion with 18.4 mol / L concentrated sulfuric acid at 80°C for 72 hours. After the reaction is completed, the entire reaction mixture is dissolved in 20 mL of distilled water and repeatedly washed three times with diethyl ether (15 mL), and then dried under vacuum (100°C) for 2 hours to obtain the desired ionic liquid 1,3-bis(butylsulfonic acid imidazolium) acidic ionic liquid. The product is confirmed to be the product shown in the above reaction formula by nuclear magnetic resonance and high-resolution mass spectrometry.

[0254] Synthesis of 1-Ethyl-3-butanesulfonic Acid Imidazolium Ionic Liquid IL2

[0255]

[0256] The synthesis process of 1-ethyl-3-butanesulfonic acid imidazolium acidic ionic liquid is as follows. It is a process of reacting 1,4-butane sultone (0.3 mol) with (0.3 mol) 1-ethylimidazole at 80°C for 24 hours, followed by hydrochloric acidization of the resulting 1-ethyl-3-butanesulfonic acid imidazolium acid at 80°C for 72 hours with 18.4 mol / L concentrated sulfuric acid. After the reaction is completed, the entire reaction mixture is dissolved in 20 mL of distilled water, washed three times with diethyl ether (15 mL), and then dried under vacuum (80°C) for 3 hours to obtain the desired ionic liquid 1-ethyl-3-butanesulfonic acid imidazolium acidic ionic liquid. The product is confirmed to be the product shown in the above reaction formula by nuclear magnetic resonance and high-resolution mass spectrometry.

[0257] Example 1:

[0258]

[0259] To an 8 mL reaction tube, N-methylquinoxalinone 1a (32.04 mg, 0.2 mmol), p-methyltriazene 2a (94.63 mg, 0.5 mmol), ionic liquid IL1 (175.22 mg, 0.4 mmol), and DMSO (4 mL) were added sequentially to obtain a mixture. The mixture was reacted at 7 mA for 4 h in an IKA ElectraSyn 2.0 pro electrochemical instrument (IKA, Germany, with a C-type cathode and a Ni-type cathode, using a diaphragm-free electrolytic cell). After the reaction, the mixture was extracted with 8 mL of dichloromethane and 8 mL of water (8 mL of dichloromethane and 8 mL of water were added to the mixture). The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting mixture was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 20:1-5:1, v / v, linear gradient) to afford a yellow solid 3aa (46.0 mg, 92% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-methyl-3-(p-tolyl)quinoxalin-2(1H)-one (3aa): Melting point: 159.7-161.1°C. 1 H NMR(600MHz, CDCl3)δ8.2(d,J=8.3Hz,2H),7.92(dd,J=8.0,1.5Hz,1H),7.55–7.52(m,1H) ,7.36–7.34(m,1H),7.31(d,J=8.4Hz,1H),7.28(d,J=7.9Hz,2H)3.75(s,3H),2.42(s,3H). 13C NMR (150MHz, CDCl3) δ154.8,154.0,140.6,133.4,133.3,133.2,130.3,130.0,129.5,128.8,123.7,113.5,29.3,21.5.

[0260] Example 2:

[0261] The reaction steps and operating conditions were the same as in Example 1, except that 2b (87.62 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3ab (38.2 mg, 81% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-methyl-3-phenylquinoxalin-2(1H)-one (3ab); Melting point: 144.2-145.5°C. 1 H NMR(600MHz, CDCl3)δ8.33–8.30(m,2H),7.95(dd,J=8.0,1.5Hz,1H),7.59–7.56(m, 1H),7.49–7.48(m,3H),7.39–7.36(m,1H),7.34(dd,J=8.3,1.3Hz,1H),3.78(s,3H). 13 C NMR (150MHz, CDCl3) δ154.9,154.3,136.2,133.5,133.3,130.6,130.5,129.7,128.2,123.9,113.7,29.4.

[0262] Example 3:

[0263] The reaction steps and operating conditions were the same as in Example 1, except that 2c (94.63 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification afforded a yellow solid 3ac (31.0 mg, 62% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-methyl-3-(o-tolyl)quinoxalin-2(1H)-one (3ac): Yellow solid. Melting point: 89.1-90.1°C. 1H NMR (600MHz, CDCl3) δ7.93 (dd, J=7.7, 0.96Hz, 1H), 7.63–7.60 (m, 1H), 7.46 (d, J= 7.5Hz,1H),7.40–7.34(m,3H),7.30(d,J=7.0Hz,2H),,3.78(s,3H),2.35(s,3H). 13 C NMR (150MHz, CDCl3) δ158.6,154.7,137.0,136.3,133.7,133.0,130.7,130.7,130.6,129.5,129.3,125.8,123.9,113.8,29.5,20.1

[0264] Example 4:

[0265] The reaction steps and operating conditions were the same as in Example 1, except that 2d (94.63 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification afforded a yellow solid 3ad (44.0 mg, 88% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-methyl-3-(m-tolyl)quinoxalin-2(1H)-one (3ad); Melting point: 108.6-109.2°C. 1 H NMR(600MHz, CDCl3)δ8.10–8.09(m,2H),7.95(dd,J=8.0,1.5Hz,1H),7.58–7.55(m,1H),7.3 9–7.36(m,2H),7.34(dd,J=8.4,1.2Hz,1H),7.30(d,J=7.5Hz,1H),3.78(s,3H),2.45(s,3H). 13 C NMR (150MHz, CDCl3) δ154.9,154.6,137.8,136.2,133.5,133.3,131.3,130.6,130.4,130.1,128.1,126.9,123.8,113.7,29.4,21.7.

[0266] Example 5:

[0267] The reaction steps and operating conditions were the same as in Example 1, except that 2e (101.65 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3ae (43.3 mg, 82% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(4-ethylphenyl)-1-methylquinoxalin-2(1H)-one (3ae): Melting point: 125.4-126.2°C. 1 H NMR(600MHz, CDCl3)δ8.25(d,J=8.3Hz,2H),7.94(dd,J=8.0,1.5Hz,1H),7.57–7.54(m,1H),7.36(td, J=7.8,1.3Hz,1H),7.32(t,J=8.2,Hz,3H),3.77(s,3H),2.72(q,J=7.6Hz,2H),1.28(t,J=7.6Hz,3H). 13 C NMR (150MHz, CDCl3) δ154.9,154.3,147.0,133.7,133.4,133.3,130.5,130.2,129.7,127.8,123.8,113.7,29.4,29.0,15.6.

[0268] Example 6:

[0269] The reaction steps and operating conditions were the same as in Example 1, except that 2f (115.59 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3af (52 mg, 89% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(4-(tert-butyl)phenyl)-1-methylquinoxalin-2(1H)-one (3af); Melting point: 90.8-92.2°C. 1 H NMR(600MHz, CDCl3)δ8.25(d,J=8.5Hz,2H),7.93(dd,J=8.0,1.5Hz,1H),7.56–7.53(m,1H),7. 51(d,J=8.5Hz,2H)7.35(td,J=7.6,1.1Hz,1H),7.32(d,J=8.3Hz,1H)3.76(s,3H),1.37(s,9H). 13CNMR (150MHz, CDCl3) δ154.9,154.3,153.7,133.5,133.4,133.3,130.5,130.1,129.4,125.2,123.7,113.6,35.0,31.3,29.4.

[0270] Example 7:

[0271] The reaction steps and operating conditions were the same as in Example 1, except that 2 g (171.65 mg, 0.5 mmol) of starting material was added to the reaction system instead of the reaction substrate (2a). Purification yielded the new compound 3ag (50.7 mg, 65% yield) as a yellow solid. Nuclear magnetic resonance and high-resolution mass spectrometry confirmed the target product. The product parameters were: 1-methyl-3-(4-undecylphenyl)quinoxalin-2(1H)-one (3ag); Melting point: 60.4-61.7°C. 1 HNMR(600MHz, CDCl3)δ8.25(d,J=8.2Hz,2H),7.93(dd,J=7.9,1.5Hz,1H),7.56–7.53(m,1H)7.37–7.34(m,1H),7.32(dd,J=8.4 ,1.2Hz,1H),7.29(d,J=8.2Hz,2H),3.76(s,3H),2.67(t,J=7.7Hz,2H),1.68–1.63(m,2H),1.27(s,18H),0.89(t,J=6.8Hz,3H). 13 C NMR (150MHz, CDCl3) δ154.9,154.2,145.8,133.6,133.4,133.3,130.4,130.1,129.6,128.3,1 23.7,113.6,36.1,32.1,31.4,29.8,29.8,29.7,29.7,29.5,29.4,29.4,22.8,14.3.HRMS(ESI + ):m / z calcd.forC 27 H 36 ON2[M+Na] + :427.2720,Found:427.2714.

[0272] Example 8:

[0273] The reaction steps and operating conditions were the same as in Example 1, except that 2h (102.56 mg, 0.5 mmol) was added to the reaction system instead of the reaction substrate (2a). Purification yielded a yellow solid 3ah (44.2 mg, 85% yield). Nuclear magnetic resonance spectroscopy confirmed the target product. The product parameters were: 3-(4-methoxyphenyl)-1-methylquinoxalin-2(1H)-one (3ah): Eluent: petroleum ether / EtOAc = 15:1 to 3:1 (v / v). 44.2 mg, 85% yield. Yellow solid. Melting point: 125.3-126.9°C. 1 H NMR(600MHz, CDCl3)δ8.40(d,J=8.9Hz,2H),7.92(dd,J=8.0,1.5Hz,1H),7.55–7.52(m,1H),7 .37–7.34(m,1H),7.32(dd,J=8.4,1.3Hz,1H),7.0(d,J=8.9Hz,2H)3.88(s,3H),3.77(s,3H). 13 CNMR (150MHz, CDCl3) δ161.5,154.9,153.2,133.2,131.4,130.1,129.8,128.8,123.7,113.5,55.4,29.3

[0274] Example 9:

[0275] The reaction steps and operating conditions were the same as in Example 1, except that 2i (96.55 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3ai (39.1 mg, 77% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(4-fluorophenyl)-1-methylquinoxalin-2(1H)-one (3ai): Yellow solid. Melting point: 151.6-152.2°C. 1 HNMR(600MHz, CDCl3)δ8.41–8.38(m,2H),7.92(dd,J=8.0,1.4Hz,1H),7.58–7.55(m, 1H),7.38–7.36(m,1H),7.33(dd,J=8.5,1.2Hz,1H),7.17–7.13(m,2H),3.76(s,3H). 13C NMR(150MHz,CDCl3)δ165.4(d,J C-F =249.0Hz),154.8,152.8,133.4,133.1,132.3(d,J C-F =3.0Hz),131.9(d,J C-F =7.5Hz),130.5,(d,J C-F =4.5Hz),123.9,115.2,115.1 113.7,29.4.

[0276] Example 10:

[0277] The reaction steps and operating conditions were the same as in Example 1, except that 2j (104.84 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3aj (35.1 mg, 65% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(4-chlorophenyl)-1-methylquinoxalin-2(1H)-one (3aj): Melting point: 177.6-179.2°C. 1 H NMR (600MHz, CDCl3) δ8.34(d,J=8.6Hz,2H),7.93(dd,J=8.0,1.4Hz,1H),7.59–7.56(m,1H ),7.44(d,J=8.6Hz,2H),7.38(td,J=7.4,1.2Hz,1H),7.33(d,J=8.3Hz,1H),3.76(s,3H). 13 C NMR (150MHz, δ154.7,152.8,136.7,134.6,133.5,133.1,131.1,130.7,130.6,128.4,124.0,113.8,29.5.

[0278] Example 11:

[0279] The reaction steps and operating conditions were the same as in Example 1, except that 2k (127.07.07 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3ak (47.1 mg, 75% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(4-bromophenyl)-1-methylquinoxalin-2(1H)-one (3ak); Melting point: 169.2-170.6°C. 1H NMR (600MHz, CDCl3) δ8.27(d,J=8.6Hz,2H),7.93(dd,J=8.0,1.5Hz,1H),7.60(d,J=8.6 Hz,2H),7.59–7.57(m,1H),7.39–7.37(m,1H)7.34(dd,J=8.4,1.1Hz,1H),3.77(s,3H). 13 C NMR (150MHz, CDCl3) δ154.7,152.9,135.0,133.5,133.1,131.4,131.3,130.7,130.7,125.2,124.0,113.8,29.5.

[0280] Example 12:

[0281] The reaction steps and operating conditions were the same as in Example 1, except that 2l (150.57 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3al (29.0 mg, 40% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(4-iodophenyl)-1-methylquinoxalin-2(1H)-one (3al): Melting point: 153.9-154.1°C. 1 H NMR (600MHz, CDCl3) δ8.12(d,J=8.6Hz,2H),7.93(dd,J=8.0,1.5Hz,1H),7.82(d,J=8.6 Hz,2H),7.60–7.57(m,1H),7.39–7.37(m,1H),7.34(dd,J=8.5,1.2Hz,1H).3.77(s,3H). 13 C NMR (150MHz, CDCl3) δ154.7,153.0,137.4,135.6,133.5,133.2,131.4,130.8,130.7,129.7,128.2,124.0,113.8,97.6,29.5.

[0282] Example 13:

[0283] The reaction steps and operating conditions were the same as in Example 1, except that 2m (96.55 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3am (36.6 mg, 72% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(3-Fluorophenyl)-1-methylquinoxalin-2(1H)-one (3am); Melting point: 172.2-173.3°C. 1 H NMR (600MHz, CDCl3) δ8.18(d,J=7.9,1H),8.11(dt,J=2.2,10.3Hz,1H),7.93(dd,J=1.4,8.5Hz,1H),7.59–7. 56(m,1H),7.45–7.42(m,2H),7.38(t,J=8.2),7.33(d,J=8.3,1H),8.11(td,J=2.7,8.3Hz,1H),3.76(s,3H). 13 C NMR(150MHz,CDCl3)δ162.6(d,J C-F =244.5Hz),154.6,152.5,138.2(d,J C-F =7.5Hz),133.5,133.0,130.9,130.7,129.6(d,J C-F =9Hz),125.4(d,J C-F =3Hz),124.0,117.3(d,J C-F =21Hz),116.65,(d,J C-F =24Hz),11.74,29.4.

[0284] Example 14:

[0285] The reaction steps and operating conditions were the same as in Example 1, except that 2n (104.84 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3an (35.2 mg, 65% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(3-Chlorophenyl)-1-methylquinoxalin-2(1H)-one (3an); Melting point: 180.6-182.2°C. 1H NMR (600MHz, CDCl3) δ8.36(t,J=1.91H),8.27(dd,J=7.7,1.4Hz,1H),7.92(dd,J=8.0,1.5,1H),7.58–7.55( m,1H),7.45–7.43(m,1H),7.40(d,J=7.8Hz,1H),7.38–7.35(m,1H),7.31(dd,J=8.5,1.2,1H),3.74(s,3H). 13 C NMR (150MHz, CDCl3) δ154.6,152.4,137.8,134.2,133.5,133.0,130.9,130.7,130.4,129.6,129.4,127.9,124.0,113.7,29.4

[0286] Example 15:

[0287] The reaction steps and operating conditions were the same as in Example 1, except that 2o (127.07.07 mg, 0.5 mmol) was added to the reaction system instead of the reaction substrate (2a). Purification afforded a yellow solid 3ao (32.8 mg, 52% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(3-Bromophenyl)-1-methylquinoxalin-2(1H)-one (3ao); Melting point: 185.6-186.2°C. 1 H NMR (600MHz, CDCl3) δ8.51(t,J=1.91H),8.33(d,J=7.8Hz,1H),7.94(dd,J=8.0,1.5Hz,1H) ,7.61–7.60(m,1H),7.60–7.58(m,1H),7.40–7.37(m,1H),7.36–7.33(m,2H),3.77(s,3H). 13 C NMR (150MHz, CDCl3) δ154.6,152.4,138.0,133.5,133.3,133.0,132.5,131.0,130.8,129.7,128.4,124.1 122.4,113.8,29.5.

[0288] Example 16:

[0289] The reaction steps and operating conditions were the same as in Example 1, except that 2p (132.58 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3ap (51.2 mg, 87% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(3-Bromophenyl)-1-methylquinoxalin-2(1H)-one (3ap); Melting point: 176.6-178.6°C. 1 H NMR (600MHz, CDCl3) δ8.38(d,J=8.5Hz,2H),8.06(d,J=8.5Hz,=2H),7.91(dd,J=7.9,1.4Hz, 1H),7.70–7.67(m,1H),7.61(d,J=8.4Hz,=1H)7.44–7.41(m,1H),3.90(s,3H),3.70(s,3H). 13 CNMR(150MHz, CDCl3)δ154.6,152.4,138.0,133.5,133.3,133.0,132.5,131.0,130.8,129.7,128.4,124.1 122.4,113.8,29.5

[0290] Example 17:

[0291] The reaction steps and operating conditions were the same as those in Example 1, except that 2q (140.53 mg, 0.5 mmol) was added to the reaction system instead of the reaction substrate (2a). Purification yielded a new yellow solid compound 3aq (44.4 mg, 68% yield). Nuclear magnetic resonance and high-resolution mass spectrometry confirmed the target product. The product parameters were: 3-(4-benzylphenyl)-1-methylquinoxalin-2(1H)-one (3aq): Melting point: 104.4-105.8°C. 1 HNMR(600MHz, CDCl3)δ8.25(d,J=8.2Hz,2H),7.93(dd,J=8.0,1.5Hz,1H),7.57–7.54(m,1H),7.38–7.3 5(m,1H)7.32(t,J=8.6Hz,3H),7.29(d,J=7.0Hz,2H),7.22(d,J=6.0Hz,3H),4.06(s,2H),3.77(s,3H). 13CNMR (150MHz, CDCl3) δ154.9,154.2,143.7,140.9,134.2,133.5,133.3,130.5,130.3,129.9,129.1 128.9,128.6,126.3,123.8,113.7,42.0,29.4.HRMS(ESI + ):m / z calcd.for C 22 H 18 N2ONa[M+Na] + :349.1311,Found:349.1304

[0292] Example 18:

[0293] The reaction steps and operating conditions were the same as in Example 1, except that 2r (148.68 mg, 0.5 mmol) was added to the reaction system instead of the substrate (2a). Purification yielded a yellow solid 3ar (50.1 mg, 70% yield). Nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry confirmed the target product. The product parameters were: 3-(4-(4-methoxyphenoxy)phenyl)-1-methylquinoxalin-2(1H)-one (3ar); Melting point: 140.3-141.5°C. 1 H NMR(600MHz, CDCl3)δ8.35(d,J=8.9Hz,2H),7.92(dd,J=8.0,1.5Hz,1H),7.57–7.54(m,1H),7.38–7.35( m,1H),7.33(dd,J=8.4,1.2Hz,1H),7.05–7.01(m,4H),6.91(d,J=9.1Hz,2H),3.82(s,3H),3.77(s,3H). 13 CNMR(150MHz, CDCl3)δ160.7,154.9,153.4,149.6,133.4,133.3,131.5,130.4,130.1,123.9,116.9,115.0,113.7,55.8,29.4.HRMS(ESI + ):m / z calcd.for C 22 H 18 N2O3Na[M+Na] + :381.1210,Found:381.1201

[0294] Example 19:

[0295] The reaction steps and operating conditions were the same as those in Example 1, except that 2s (140.68 mg, 0.5 mmol) was added to the reaction system instead of the reaction substrate (2a). Purification yielded a yellow oily liquid 3as (49.3 mg, 72% yield). Nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry confirmed the target product. The product parameters were 1-methyl-3-(4-(p-tolyloxy)phenyl)quinoxalin-2(1H)-one (3as). 1 H NMR(600MHz, CDCl3)δ8.36(d,J=8.8Hz,2H),7.92(dd,J=8.0,1.5Hz,1H),7.57–7.54(m,1H),7.38–7.35(m,1H),7.33( dd,J=8.5,1.3Hz,1H),7.17(d,J=8.3Hz,2H),7.06(d,J=8.8Hz,2H),6.99(d,J=8.4Hz,2H),3.77(s,3H),2.36(s,3H). 13 C NMR (150MHz, CDCl3) δ160.1,154.9,154.1,153.4,133.6,133.4,133.3,131.6, 130.7,130.5,130.4,130.2,123.9,119.8,117.5,113.7,29.4,20.9.HRMS(ESI + ):m / z calcd.for C 22 H 18 N2O2Na[M+Na] + :365.1261,Found:365.1255.

[0296] Example 20:

[0297] The reaction steps and operating conditions were the same as those in Example 1, except that 2t (112.68 mg, 0.5 mmol) was added to the reaction system instead of the reaction substrate (2a). Purification yielded a red solid 3at (38.9 mg, 68% yield). Nuclear magnetic resonance spectroscopy confirmed the target product. The product parameters were 1-methyl-3-(naphthalen-2-yl)quinoxalin-2(1H)-one (3at). 4 :Melting point:155.3-156.9℃. 1H NMR(600MHz, CDCl3)δ8.00–7.96(m,2H),7.92–7.90(m,2H),7.77(dd,J=7.1,1.2Hz,1H),7.66 –7.63(m,1H),7.59(dd,J=8.2,7.1Hz,1H),7.51–7.45(m,2H),7.43–7.40(m,2H),3.82(s,3H). 13 C NMR (150MHz, CDCl3) δ157.5,155.1,134.0,133.9,133.8,133.1,131.6,130.9 ,130.7,130.2,128.6,127.8,126.6,126.0,125.4,125.1,124.0,113.9,29.6.

[0298] Example 21:

[0299] The reaction steps and operating conditions were the same as in Example 1, except that quinoxalinone 1b (29.23 mg, 0.2 mmol) was added to the reaction system instead of the substrate (1a), 3ba (33.1 mg, 70% yield). Nuclear magnetic resonance spectroscopy confirmed the target product. The product parameters were: 3-(p-tolyl)quinoxalin-2(1H)-one (3ba): Yellow solid. Melting point: 241.6-243.2°C. 1 H NMR (600MHz, DMSO-d6) δ12.53(s,1H),8.26(d,J=8.2Hz,2H),7.82(dd,J=8.0,1.4Hz,1H),7.54–7.51(m,1H)7.34–7.29(m,4H),2.38(s,3H). 13 C NMR (150MHz, DMSO-d6) δ154.6,153.8,140.1,132.9,132.0,131.9,130.1,129.2,128.6,128.5,123.4,115.0,21.1.

[0300] Example 22:

[0301] The reaction steps and operating conditions were the same as those in Example 1, except that 1c (34.82 mg, 0.2 mmol) was added to the reaction system instead of the reaction substrate (1a). Purification yielded a yellow solid 3ca (42.8 mg, 81% yield). Nuclear magnetic resonance spectroscopy confirmed the target product. The product parameters were 1-ethyl-3-(p-tolyl)quinoxalin-2(1H)-one (3ca). 6 :Melting point:125.6-126.2℃., 1 H NMR(600MHz, CDCl3)δ8.26(d,J=8.0Hz,2H),7.95(dd,J=8.2,1.6Hz,1H),7.56–7.53(m,1H),7.3 6–7.34(m,2H),7.29(d,J=7.9Hz,2H),4.39(q,J=7.2Hz,2H),2.42(s,3H),1.42(t,J=7.1Hz,3H). 13 C NMR (150MHz, CDCl3) δ154.4,154.1,140.7,133.6,133.4,132.4,130.7,130.1,129.7,128.9,123.6,113.5,37.7,21.6,12.5

[0302] Example 23:

[0303] The reaction steps and operating conditions were the same as in Example 1, except that 1d (37.62 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded a white solid, 3da (41.7 mg, 75% yield). Nuclear magnetic resonance and high-resolution mass spectrometry confirmed the target product. The product parameters were: 1-propyl-3-(p-tolyl)quinoxalin-2(1H)-one (3da): Melting point: 69.8-71.1°C. 1 H NMR(600MHz, CDCl3)δ8.26(d,J=8.3,2H),7.94(dd,J=8.0,1.4Hz,1H),7.55–7.52(m,1H),7.36–7.34(m,1H),7.32(d,J= 8.2Hz,1H),7.29(d,J=8.0Hz,2H),4.29–4.27(m,2H),2.42(s,3H),1.85(td,J=15.1,7.4Hz,2H),1.09(t,J=7.4Hz,3H). 13CNMR (150MHz, CDCl3) δ154.6,154.1,140.7,133.6,133.5,132.6,130.7,130.1,129.7,128.9,123.6,113.7,44.2,21.6,20.8,11.6.HRMS(ESI + ):m / z calcd.forC 18 H 18 N2ONa[M+Na] + :301.1311,Found:301.1311.

[0304] Example 24:

[0305] The reaction steps and operating conditions were the same as in Example 1, except that 1e (37.22 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded a yellow solid 3ea (50.8 mg, 92% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-allyl-3-(p-tolyl)quinoxalin-2(1H)-one (3ea): Melting point: 98.6-99.5°C. 1 H NMR(600MHz, CDCl3)8.27(d,J=8.2Hz,2H),7.94(dd,J=8.0,1.6Hz,1H),7.53–7.50(m,1H),7.36–7.34(m,1H),7.30(t,J=8 .3Hz,3H),6.02–5.96(m,1H),5.29(dd,J=10.3,1.1Hz,1H),5.22(dd,J=17.3,1.3Hz,1H),4.98–4.97(m,1H),2.42(s,3H). 13 C NMR (150MHz, CDCl3) δ154.5,154.1,140.8,133.5,133.4,132.7,130.9,130.6,130.1,129.7,128.9,123.8,118.2,114.2,44.8,21.7

[0306] Example 25:

[0307] The reaction steps and operating conditions were the same as in Example 1, except that 1f (36.81 mg, 0.2 mmol) was added to the reaction system instead of the substrate (1a). Purification yielded a yellow solid, 3fa (45.0 mg, 82% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-(prop-2-yn-1-yl)-3-(p-tolyl)quinoxalin-2(1H)-one (3fa); Melting point: 172.6-173.2°C. 1 H NMR (600MHz, CDCl3) δ8.26(d,J=8.2Hz,2H),7.95(dd,J=8.0,1.5Hz,1H),7.60–7.57(m,1H),7.47(d,J=8.3H z,1H), δ7.40–7.38(m,1H),7.29(d,J=8.0Hz,2H),5.12(d,J=2.5Hz,2H),2.43(s,3H),2.30(t,J=2.5Hz,1H). 13 C NMR (150MHz, CDCl3) δ154.0,153.9,141.0,133.5,133.2,131.9,130.6,130.3,129.7,129.0,124.2,114.1,73.2,31.8,21.7

[0308] Example 26:

[0309] The reaction steps and operating conditions were the same as in Example 1, except that 1 g (40.02 mg, 0.2 mmol) of starting material was added to the reaction system instead of the reaction substrate (1a). Purification yielded a yellow solid 3ga (37.7 mg, 65% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-(cyclopropylmethyl)-3-(p-tolyl)quinoxalin-2(1H)-one (3ga): Melting point: 96.6-99.1°C. 1 H NMR (600MHz, CDCl3) δ8.24(d,J=8.2Hz,2H),7.95(dd,J=8.0,1.6Hz,1H),7.56–7.53(m,1H),7.44(dd,J=8.5,1.2Hz,1 H),7.36–7.33(m,1H)7.29(d,J=8.0Hz,2H),4.27(d,J=7.0Hz,2H),2.42(s,3H),1.36–1.29(m,1H),0.62–0.55(m,4H). 13C NMR (150MHz, CDCl3) δ154.9,154.4,140.7,133.6,133.5,132.8,130.7,130.0,129.7,128.9,123.6,113.9,46.4,21.6,9.8,4.3

[0310] Example 27:

[0311] The reaction steps and operating conditions were the same as in Example 1, except that 1h (48.43 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded the new compound 3ha (42.9 mg, 62% yield) as a yellow solid. Nuclear magnetic resonance and high-resolution mass spectrometry confirmed the target product. The product parameters were: 1-(2-cyclohexylethyl)-3-(p-tolyl)quinoxalin-2(1H)-one (3ha); Melting point: 100.6-101.8°C. 1 H NMR(600MHz, CDCl3)δ8.25(d,J=8.2Hz,2H)7.93(dd,J=7.9,1.5Hz,1H),7.54–7.51(m,1H),7.35–7.32(m,2H),7. 29(d,J=7.9Hz,2H),4.21(d,J=7.3Hz,2H),2.42(s,3H),1.98–1.94(m,1H),1.75–1.65(m,6H),1.21–1.19(m,4H). 13 C NMR (150MHz, CDCl3) δ155.0,154.1,140.7,133.5,133.5,133.1,130.7,129. 9,129.7,128.9,123.5,114.1,48.3,36.7,31.1,26.3,26.0,21.6.HRMS(ESI + ):m / z calcd.for C 22 H 24 N2O[M+H] + :333.1961,Found:333.1956.

[0312] Example 28:

[0313] The reaction steps and operating conditions were the same as in Example 1, except that 1i (46.42 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded a yellow solid 3ia (47.7 mg, 74% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: ethyl 2-(2-oxo-3-(p-tolyl)quinoxalin-1(2H)-yl)acetate (3ia); Melting point: 159.8-161.1°C. 1 H NMR (600MHz, CDCl3) δ8.27(d,J=8.3Hz,2H),7.95(dd,J=8.0,1.5Hz,1H),7.53–7.50(m,1H),7.38–7.35(m,1H),7. 29(d,J=7.9Hz,2H),7.09(d,J=7.2Hz,1H),5.08(s,2H),4.26(q,J=7.1Hz,2H),2.42(s,3H),1.28(t,J=7.1Hz,3H). 13 C NMR (150MHz, CDCl3) δ167.4,154.5,153.8,140.9,133.3,133.1,132.5,130.8,130.3,129.7,128.9,128.1,124.1,113.1,62.2,43.9,21.6,14.2.

[0314] Example 29:

[0315] The reaction steps and operating conditions were the same as in Example 1, except that 1j (52.82 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded a yellow solid 3ja (36.8 mg, 52% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1-(2-oxo-2-phenylethyl)-3-(p-tolyl)quinoxalin-2(1H)-one (3ja); Melting point: 185.8-186.1°C. 1H NMR (600MHz, CDCl3) δ8.27(d,J=8.3Hz,2H),8.10(dd,J=8.2,1.2Hz,2H),7.97(dd,J=8.0,1.5Hz,1H),7.70–7.67(m,1H),7.57–7 .55(m,2H),7.46–7.43(m,1H),7.36–7.34(m,1H),7.29(d,J=7.7Hz,2H),6.98(dd,J=8.5,1.2Hz,1H),5.80(s,2H),2.42(s,3H). 13 C NMR (150MHz, CDCl3) δ191.4,154.6,153.8,140.9,134.8,134.4,133.5,133.3 ,132.9,130.8,130.2,129.7,129.2,129.0,128.3,123.6,113.5,48.8,21.7.

[0316] Example 30:

[0317] The reaction steps and operating conditions were the same as in Example 1, except that 1k (47.59 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded a yellow solid 3ka (34.1 mg, 52% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 6-bromo-1-methyl-3-(p-tolyl)quinoxalin-2(1H)-one (3ka); Melting point: 155.8-157.1°C. 1 H NMR (600MHz, CDCl3) δ8.23(d,J=8.2Hz,2H),7.76(d,J=8.4Hz,1H),7.46–7.44(m,2H),7.28(d,J=8.0Hz,2H),3.71(s,3H),2.42(s,3H). 13 C NMR (150MHz, CDCl3) δ154.5,154.2,141.1,134.4,133.1,132.1,131.6,129.7,129.0,127.1,116.7,29.5,21.7.

[0318] Example 31:

[0319] The reaction steps and operating conditions were the same as in Example 1, except that 1l (37.62 mg, 0.2 mmol) was added to the reaction system instead of the reaction substrate (1a). Purification yielded a yellow solid 3la (44.1 mg, 72% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 1,6,7-trimethyl-3-(p-tolyl)quinoxalin-2(1H)-one (3la); Melting point: 195.8-196.7°C. 1 H NMR (600MHz, CDCl3) δ8.22(d,J=8.2Hz,2H),7.68(s,1H),7.27(d,J=7.9Hz,2H),7.08(s,1H),3.73(s,3H),2.42(d,J=8.0Hz,6H),2.36(s,3H). 13 C NMR (150MHz, CDCl3) δ155.0,153.0,140.3,140.1,133.8,132.7,131.7,131.5,130.5,129.5,128.9,114.2,29.3,21.6,20.8,19.3.

[0320] Example 32:

[0321] The reaction steps and operating conditions were the same as in Example 1, except that 1m (45.60 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded a yellow solid 3ma (47.1 mg, 68% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 6,7-dichloro-1-methyl-3-(p-tolyl)quinoxalin-2(1H)-one (3ma); Melting point: 183.8-185.1°C. 1 H NMR (600MHz, CDCl3) δ8.23(d,J=8.3Hz,2H),7.97(s,1H),7.37(s,1H),7.27(d,J=8.5Hz,2H),3.68(s,3H),2.42(s,3H). 13 C NMR (150MHz, CDCl3) δ154.9,154.3,141.5,134.0,132.7,132.7,132.3,131.0,129.8,129.0,127.5,115.1,29.6,21.7

[0322] Example 33:

[0323] The reaction steps and operating conditions were the same as in Example 1, except that 2-methylquinoxaline 1n (28.81 mg, 0.2 mmol) was added to the reaction system instead of the reaction substrate (1a). Purification yielded a red oily liquid 3na (15.7 mg, 30% yield). Nuclear magnetic resonance spectroscopy confirmed the target product. The product parameters were: 2-methyl-3-(p-tolyl)quinoxaline (3na): 1 H NMR (600MHz, CDCl3) δ8.10 (dd, J=7.8, 1.9Hz, 1H), 8.05 (dd, J=7.9, 1.9Hz, 1H), 7.76– 7.67(m,2H),7.56(d,J=7.8Hz,2H),7.33(d,J=7.8Hz,2H),2.79(s,3H),2.45(s,3H). 13 C NMR (150MHz, CDCl3) δ155.1,152.8,141.3,140.8,138.3,136.3,129.7,129.4,129.4,129.3,129.0,128.4,24.6,21.5.

[0324] Example 34:

[0325] The reaction steps and operating conditions were the same as in Example 1, except that 2-aminoquinoxaline 1o (29.01 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification afforded a red solid 3oa (32.6 mg, 62% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(p-tolyl)quinoxalin-2-amine (3oa): Melting point: 173.8-175.1°C. 1 H NMR (600MHz, CDCl3) δ7.95 (dd, J=8.2, 1.5Hz, 1H), 7.68–7.66 (m, 3H), 7.59–7. 57(m,1H),7.45–7.42(m,1H),7.34(d,J=7.8Hz,2H),5.23(s,2H),2.43(s,3H). 13 C NMR (150MHz, CDCl3) δ150.8,146.1,141.2,140.0,138.3,134.2,130.0,130.0,129.1,128.4,125.7,125.3,21.5.

[0326] Example 35:

[0327] The reaction steps and operating conditions were the same as in Example 1, except that 2-mercaptoquinoxaline 1p (32.41 mg, 0.2 mmol) was added to the reaction system instead of the reaction substrate (1a). Purification afforded a yellow oily liquid 3pa (26.9 mg, 48% yield). Nuclear magnetic resonance analysis confirmed the target product. The product parameters were: 3-(p-tolyl)quinoxaline-2-thiol (3pa): 1 H NMR (600MHz, CDCl3) δ8.40(s,1H),7.98(dd,J=8.3,1.5Hz,1H),7.90(dd,J=8.4,1.5Hz,1H),7. 70–7.67(m,1H),7.64–7.61(m,2H),7.56(d,J=8.1Hz,2H),7.28(d,J=8.0Hz,2H),2.42(s,3H). 13 C NMR (150MHz, CDCl3) δ157.9,143.4,142.3,140.2,140.0,135.3,130.8,130.6,129.3,128.8,128.4,125.3,21.5

[0328] Example 36:

[0329] The reaction steps and operating conditions were the same as in Example 1, except that 2-methyldibenzoquinoxaline 1q (48.82 mg, 0.2 mmol) was added to the reaction system instead of substrate (1a). Purification yielded the new compound 3qa (30.4 mg, 52% yield) as a yellow solid. Nuclear magnetic resonance and high-resolution mass spectrometry confirmed the target product. The product parameters were: 2-methyl-3-(p-tolyl)dibenzo[f,h]quinoxaline (3qa): Melting point: 128.8-130.1°C. 1 H NMR (600MHz, CDCl3) δ9.27–9.26(m,2H),8.63–8.60(m,2H),7.77–7.34(m,5H),7.73–7.70(m,1H),7.38(d,J=7.4Hz,2H),2.92(s,3H),2.49(s,3H). 13C NMR (150MHz, CDCl3) δ152.7,150.8,138.9,138.8,138.6,136.7,131.4,131.2,130.3,130.0, 129.6,129.2,129.1,129.0,127.6,127.6,125.5,125.4,122.9,122.8,24.3,21.5.HRMS(ESI + ):m / z calcd.for C 24 H 18 N2[M+H] + :335.1543,Found:335.1537

[0330] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for electrochemical synthesis of 3-arylquinoxalinone compounds, characterized in that: Using quinoxalinone compound 1 and aryl triazene 2 as reaction substrates, and ionic liquid as electrolyte and promoter, the product 3 of arylation of quinoxalinone compound 3 was obtained under electrochemical reaction conditions. The synthesis route is shown in the following reaction formula: ； In the reaction formula: R1 is H, methyl, chlorine or bromine, and the number is 1-3; R2 is H, methyl, methoxy, C2-C 12 The invention relates to an alkyl group, a tert-butyl group, a halogen group, a C2-C6 ester group, a benzyl group, a 4-methyldiphenyl ether group and a 4-methoxydiphenyl ether group, wherein the halogen group is fluorine, chlorine, bromine or iodine; R3 is a methyl group, H, an ethyl group, a propyl group, an allyl group, a propargyl group, a cyclopropyl group, a cyclopropylmethylene group, a benzyl group, a cyclohexylmethylene group, a benzoylmethyl group, a cyclohexyl group, a C2-C6 ester group and a benzoyl group; the electrochemical reaction conditions are as follows: the reaction current is 4-7 mA, the positive electrode is a C electrode, the negative electrode is a Ni electrode, and the electrochemical reaction is carried out in an electrolytic cell without a diaphragm.

2. The synthesis method according to claim 1, characterized in that: The reaction is carried out in a solvent, which is methanol, ethanol, acetonitrile, N,N - one of dimethylformamide, trifluoroethanol, dimethyl sulfoxide, dimethyl sulfoxide and acetonitrile in a volume ratio of 1:0.5-2, and the amount of the solvent is 3-10 mL of the solvent per 0.2 mmol of the quinoxalinone compound 1.

3. The synthesis method according to claim 1, wherein: The ionic liquid is 1,3-bis(butylsulfonic acid imidazole) acidic ionic liquid , 1-ethyl-3-butanesulfonic acid imidazolium acidic ionic liquid Any one or two of the above, with the dosage being 0.2-0.8 mmol of ionic liquid added per 0.2 mmol of quinoxalinone compound 1.

4. The synthesis method according to claim 1, characterized in that: The electrochemical reaction condition is that the reaction current is 6-8 mA.

5. The synthesis method according to claim 1, characterized in that: When the quinoxalinone compound 1 reacts with the aryl triazene 2, the molar ratio of the quinoxalinone compound 1 to the aryl triazene 2 is in the range of 1:1-3.

6. The synthesis method according to claim 1, characterized in that: The reaction time is 2-7 h.

7. The synthesis method according to claim 6, characterized in that: The reaction time is 3-5 h.

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