Construction Of C-N Bonds And C-P Bonds Under Electrochemical Conditions

Nitrogen-containing compounds are widely found in natural products,pharmaceuticals,bioactive compounds and organic materials.Among them,3-aminoquinoxaline and carbazole compounds synthesized by constructing C-N bonds have great research value.Quinoxaline-2(1H)-ones derivatives are important chemical structural units in nitrogen-containing heterocyclic compounds,especially 3-aminoquinoxalinone,which has good applications in antimicrobial,antiviral and disease treatment.Carbazole and its derivatives have unique biological activities,such as anti-bacterial,anti-inflammatory,anti-virus,anti-HIV.Moreover,indole [3,2-b]carbazole is used to construct organic photoelectric materials because of its ?-conjugated system.Phosphorus-containing compounds not only have good medicinal activity,but also have important significance in organic synthesis,catalytic chemistry,biochemistry and materials science.Among them,the phosphoryl group modification of quinoxaline-2(1H)-ones C-3 position by constructing C-P bonds has potential research value.Based on the important significance of 3-aminoquinoxaline,carbazole,3-phosphonated quinoxalin-2(1H)-ones in medicine and treatment,it is necessary to develop a simple,efficient and green method to construct C-N bonds and C-P bonds.In this paper,electrochemical direct electrolysis is used to construct C-N bonds to synthesize 3-aminoquinoxaline,carbazole compounds,and construct C-P bonds to synthesize 3-phosphonated quinoxalin-2(1H)-ones.This paper has carried out the following three aspects of work:(1)Electrochemical synthesis of 3-aminoquinoxalines by constructing C-N bondsA mild,green and efficient electrochemical method was established to construct C-N bonds to synthesize 3-aminoquinoxaline-2(1H)-one compounds.Firstly,the effects of various electrolysis parameters on the reaction were investigated,the reaction conditions were optimized,and the universality of the substrate was investigated under these conditions.The gram-scale experiment proves that the reaction has potential application value.Finally,through the control experiment and the measurement of cyclic voltammetry,the possible reaction mechanism was deduced.The reaction is directly electrolyzed at a constant current in undivided cell at room temperature,without added metal catalysts,oxidants,using "clean energy" electrons instead of oxidants.The method avoids using toxic and harmful metals and oxidants,has the characteristics of mild conditions,simple operation,green environmental protection and strong controllability.Therefore,it is a method for efficiently constructing C-N bonds to synthesize 3-aminoquinoxaline-2(1H)-ones.(2)Electrochemical synthesis of carbazoles by constructing C-N bondsA mild,green and efficient electrochemical method was established to construct C-N bonds and synthesised carbazoles.Firstly,the effects of various electrolysis parameters on the reaction were investigated,the reaction conditions were optimized,and the universality of the substrate was investigated under optimal conditions.Secondly,the possible reaction mechanism was speculated through control experiments.The reaction is carried out by direct current electrolysis in undivided cell,without adding metal catalyst,oxidants and so on,and the use of electrons instead of the oxidants.The reaction is simple in operation and mild in condition,and it is an efficient method to synthesize carbazole compounds.(3)Electrochemical synthesis of 3-phosphonated quinoxalin-2(1H)-ones by constructing C-P bondsA mild,green and efficient direct electrolysis method was established to construct C-P bonds and synthesize 3-phosphonated quinoxalin-2(1H)-ones.Firstly,the effects of various electrolysis parameters on the reaction were investigated,the reaction conditions were optimized,and the universality of the substrate was investigated under these conditions.Secondly,the gram-scale experiment proves that the reaction has potential application value.Finally,through the control experiments and the gas chromatography detection,the possible reaction mechanism was inferred.This method is carried out in an undivided cell with direct electrolysis,in this reaction,no additive,metal catalyst and oxidants were added,and electrons generated during the electrolysis are used instead of the oxidants.The reaction is environmentally friendly,mild and easy to operate.Therefore,it is a simple and efficient method for constructing C-P bonds to synthesize 3-phosphoroquinoxaline-2(1H)-one compounds.