Abstract Heating 2-hydrazinoperimidine (2) with acetylacetone in absolute ethanol gave exclusively 2-(3, 5-dimethyl-1-pyrazolyl) perimidine (4) via a [2+ 3] cyclization. The possible [4+ 3] condensate, 3, 5-dimethyl-1H-1, 2, 4-triazepino [4, 3-a] perimidine (5) was not
