Iodine Catalyzed Oxidative Synthesis of Quinazolin-4(3H)-ones and Pyrazolo[4,3-d]pyrimidin-7(6H)-ones via Amination of sp3 C-H Bond

Molecular iodine catalyzed oxidative coupling of 2-aminobenzamides with aryl methyl ketones produced 2-aryl quinazolin-4(3H)-ones. The reaction performed well in the absence of any metal or ligand. The quantity of iodine played a very crucial role in this transformation in order to selectively get 2-aryl quinazolin-4(3H)-ones. The utility of this protocol for synthesis of pyrazolo[4,3-d]pyrimidin-7(6H)-ones including a key intermediate involved in sildenafil synthesis has also been demonstrated.