The molecule is an indole alkaloid that is the enol tautomer of geissoschizine, which is also dehydrogenated at the 4,21-position. It derives from a geissoschizine.
methyl (Z)-2-[(2S,3E,12bS)-3-ethylidene-1,2,6,7,12,12b-hexahydroindolo[2,3-a]quinolizin-5-ium-2-yl]-3-hydroxyprop-2-enoate