An efficient synthesis of 4,6-dihydrospiro[azepino[4,3,2-cd]indole-3,3′-indoline]-2′,5(1H)-diones via multi-component reaction

A facile and efficient one-pot three-component synthesis of spiroazepinoindolones has been developed. Using DMF as solvent without any additional acid or metal catalysts, the three-component reaction of readily available isatins, indolamines, and Meldrum's acid affords a new class of spiroheterocycles in moderate yield.