(Z)-2-Methyl-2-butenoic acid [(1S,2R,7aS)-hexahydro-1-hydroxymethyl-1H-pyrrolizin-2-yl] ester

A simple pyrrolizidine alkaloid, petasinine occurs in the stalks of Petasites japonicus Maxim. It forms an amorphous white powder having no definite melting point. The base is dextrorotatory with a specific rotation of [α]D + 16° (c 2.5, EtOH). The phenylurethane has been prepared as colourless needles with m.p. 168-17loC and [α]D +14° (c 2.5, EtOH). Hydrolysis furnishes angelic acid and petasinecine, m.p. 132-134°C, [α]D -20° (c 0.25, EtOH).

ChEBI: Petasinine is a member of pyrrolizines.