The molecule is an ammonium ion resulting from the addition of a proton to the piperazine nitrogen which is attached to the alkyl chain. The major species at pH 7.3. It is a conjugate acid of a tandospirone.
(1S,2R,6S,7R)-4-[4-(4-pyrimidin-2-ylpiperazin-1-ium-1-yl)butyl]-4-azatricyclo[5.2.1.02,6]decane-3,5-dione