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