Copper-catalyzed Synthesis Of Indole Derivatives

Indole derivatives are one of the most widely distributed nitrogen heterocyclecompounds in nature. They widely occur in various natural products and biologicallyactive molecules. Functionalized indoles have been obtained wide application in manyresearch fields, such as pharmaceutical, pesticide, fragrance, dye and materialsscience. In recent decades, with the development of transition metal catalysischemisty, chemists pay much attention to C-H functionalization of indoles. In thisdissertation, the copper-catalyzed synthesis of indole derivatives were studied, andsome results were obtained as follows:A novel and efficient method for synthesis of indoloimidazoquinoline derivativeshas been developed through one-pot copper-catalyzed N-arylation and aerobicoxidative C-H/C-H coupling and achieved the regioselectivity C-H functionalizationat C3of indole. Reaction of2-(2-bromophenyl)-indole with imidazole was used asmodel reaction to optimize reaction conditions including catalysts, bases, ligands,solvents, acid additives and oxidants. The protocol uses CuBr as the catalyst, Cs2CO3as the base,1,10-phen as the ligand, DMSO as the solvent and the acid additivePivOH,110oC as the temperature under the optimized conditions. The relevantindoloimidazoquinoline derivatives were obtained in good yields. The experimentalresults showed that the cascade reactions are applicable to indole, imidazole andbenzimidazole attatched halogen, alkyl, alkoxy and heterocycle. The reactionunderwent the one-pot sequential process: N-arylation, intramolecular cycliazation,and aerobic oxidation. This method has the advantages of high regioselectivity,efficient and environmental-friend.