(+)-CPCA ("nocaine") is the 3"R",4"S" piperidine stereoisomer of (phenyltropane based) RTI-31. It is non addictive, although this might be due to it being a NDRI, not a SNDRI. The β-naphthyl analog of "Nocaine" is a SNDRI though in the case of both the "SS" and "RR" enantiomers. Consider the piperidine analogs of brasofensine and tesofensine. These were prepared by NeuroSearch (In Denmark) by the chemists Peter Moldt (2002), and Frank Wätjen (2004–2009). There are four separate isomers to consider ("SS", "RR", "S/R" and "R/S"). This is because there are two chiral carbon sites of asymmetry (means 2 to the power of n isomers to consider where n is the number of chiral carbons). They are therefore a diastereo(iso)meric pair of racemers. With a racemic pair of diastereomers, there is still the question of syn (cis) or anti (trans). In the case of the phenyltropanes, although there are four chiral carbons, there are only eight possible isomers to consider. This is based on the fact that the compound is bicyclic and therefore does not adhere to the equation given above.