Regioselective aluminium chloride induced heteroarylation of pyrrolo[1,2-b]pyridazines: its scope and application

We describe a detailed study on the novel synthesis of 6,7-disubstituted pyrrolo[1,2-b]pyridazines through AlCl3 induced C–C bond formation reactions. A wide variety of 6-aryl substituted azolopyridazines was reacted with 3,6-dichloropyridazine to give 7-pyridazinyl substituted pyrrolopyridazines regioselectively in good to excellent yield. The mechanism and regiochemistry of the reaction along with applications of the methodology are discussed.