Discovery Of New Ligands 1,10-phenanthroline -N-oxide For Studying Copper-Catalyzed C-N Coupling Reactions At Moderate-Temperature

CuI/1,10-phenanthroline-N-oxide was discovered to be a new catalytic systems. Then, the new systems was applied in the Ullmann C-N coupling reaction. 1,10-phenanthroline-N-oxide was prepared as an efficient ligand for the coupling reaction which aryl halides reacted with N-heterocylic compounds or primary amines at moderate elevated temperature.In the process of reaction,1,10 phenanthroline ligands has been used to synthesize the 1, 10 phenanthroline-N-oxide. Then, the new catalytic systems was applied in the Ullmann C-N coupling reaction. When 4-methoxy iodobenzene reacted with pyrazole, the optimized conditions of the reaction were found, such as Catalyst, Ligands, Solvents, Alkali. We finally found the optimal condition is 10 mol% Cul,20 mol% L2, and Cs2CO3 (2.0 eq) in DMF at moderate temperature. From 3a to 7h compounds was synthesized by using the optimized conditions and the compounds was verified through the 1H NMR,13C NMR and MS.A new catalytic system was discoveried and used to synthesize the compounds of different substrates in this paper. The aryl halides reacted with N-heterocylic compounds or primary amines by using the catalytic system, which can explore the merits of the catalytic system and speculation the mechanism of the reaction.