Synthesis of 10-Methylacridin-9(10H)-ones through Cu-Catalyzed Intramolecular Oxidative C(sp2)-H Amination of 2-(Methylamino)benzophenones

An efficient synthesis of a diverse set of 10-methylacridin-9(10H)-ones from 2-(methylamino)benzophenones has been developed. The reaction proceeds though Cu-catalyzed intramolecular aromatic C-H amination by using O-2 as the sole oxidant to provide the desired products in moderate to good yields. In addition, 2-allylamino-and 2-(benzylamino)benzophenones as well as unprotected substrates can also undergo the C-H amination reaction to deliver the corresponding cyclization products smoothly. Preliminary mechanistic studies suggest that C-H activation is involved in a rate-limiting step.