6,8-Dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-dione: a novel approach to imidazoline (imidazole) ring annulation based on the SNH methodology

The N₍₂₎-oxide and 3-amino derivatives of the title compound react with alkylamines in the presence of an oxidant to produce condensed imidazolines or their imidazole analogues.