Synthesis and monoamine transporter affinity of new 2β-carbomethoxy-3β-[4-(substituted thiophenyl)]phenyltropanes: discovery of a selective SERT antagonist with picomolar potency

Preparation of cocaine analogues has been aimed largely at development of stable compounds with high affinity and selectivity for the dopamine transporter (DAT). We now report the synthesis and monoamine transporter affinity of 10 new 2β-carbomethoxy-3β-[4-(substituted thiophenyl)]phenyltropanes. Among these, compound 4b exhibited very high affinity for the serotonin transporter (SERT: Ki = 17 pM) and good selectivity over dopamine (DAT: 710-fold) and norepinephrine transporters (NET: 11,100-fold).