2-Acetyl-1-pyrroline, abbreviated 2AP, with the IUPAC name 1-(3,4-dihydro-2H-pyrrol-5-yl)ethanone, is an aroma compound and flavor that gives white bread, jasmine rice and basmati rice, the spice pandan (Pandanus amaryllifolius), and bread flowers (Vallaris glabra) their customary smell. Many observers describe the smell as similar to "hot, buttered popcorn", and it is credited for lending this odor to the scent of binturong (bearcat) urine. 2-Acetyl-1-pyrroline and its structural homolog, 6-acetyl-2,3,4,5-tetrahydropyridine of similar smell, can be formed by Maillard reactions during heating of food such as the baking of bread dough. Both compounds have odor thresholds below 0.06 ng/l.
2-Acetyl-1-pyrroline is a substituted pyrroline and a cyclic imine as well as a ketone.