The molecule is an ammonium ion resulting from the protonation of the tertiary amino group of O-acetyl-15alpha-stemmadenine. The major species at pH 7.3. It is a conjugate acid of an O-acetyl-15alpha-stemmadenine.
methyl (1S,2S,16E)-2-(acetyloxymethyl)-16-ethylidene-4-aza-14-azoniatetracyclo[12.2.2.03,11.05,10]octadeca-3(11),5,7,9-tetraene-2-carboxylate