(–)-2β-Carbomethoxy-3β-(4-ethylphenyl)tropane (RTI-83) is a phenyltropane derivative which represents a rare example of an SDRI or serotonin-dopamine reuptake inhibitor, a drug which inhibits the reuptake of the neurotransmittersserotonin and dopamine, while having little or no effect on the reuptake of the related neurotransmitter noradrenaline. With a binding affinity (Ki) of 55 nM at DAT and 28.4 nM at SERT but only 4030 nM at NET, RTI-83 has reasonable selectivity for DAT/SERT over NET, but further research has shown that by extending the ethyl chain even better selectivity can be achieved, with the 4′-(cis-propenyl) analogue having Ki values of 15 nM at DAT and 7.1 nM at SERT, vs 28,000 nM at NET.[1][2]
cis-propenyl analogue (RTI-11w)
Such drugs are speculated to be useful as potential antidepressants, but few examples have been reported in the literature as yet. However while RTI-83 has been used for binding studies to model the monoamine transporter proteins,[3] its pharmacology in vivo has not been studied in detail.
^Blough BE, Abraham P, Lewin AH, Kuhar MJ, Boja JW, Carroll FI. Synthesis and transporter binding properties of 3 beta-(4′-alkyl-, 4′-alkenyl-, and 4′-alkynylphenyl)nortropane-2 beta-carboxylic acid methyl esters: serotonin transporter selective analogs. Journal of Medicinal Chemistry. 1996 Sep 27;39(20):4027-35. PMID 8831768
^Singh S (March 2000). "Chemistry, design, and structure-activity relationship of cocaine antagonists". Chemical Reviews100 (3): 925–1024. doi:10.1021/cr9700538. PMID11749256.
^Roman DL, Saldaña SN, Nichols DE, Carroll FI, Barker EL. Distinct molecular recognition of psychostimulants by human and Drosophila serotonin transporters. Journal of Pharmacology and Experimental Therapeutics. 2004 Feb;308(2):679-87. PMID 14593087
