Synthesis and transporter binding properties of (R)-2β,3β- and (R)-2α,3α-diaryltropanes

(R)-2-Aryl-2-tropinone (9) was synthesized from (R)-2-carbomethoxy-3-tropinone (5) and was used as the key intermediate for the synthesis of (R)-2β,3β- and (R)-2α,3α-diaryltropanes. Inhibition of radioligand binding studies at the dopamine, serotonin, and norepinephrine transporters showed that the (R)-3β-(4-methylphenyl)-2β-phenyltropane (3b, RTI-422) possessed an IC50 value of 1.96 nM at the dopamine transporter and was highly selective for this transporter relative to the serotonin and norepinephrine transporters.