Systematic (IUPAC) name
methyl (1R,2S,3S)-3-(4-iodophenyl)-8-methyl -8wogga wogga[3.2.1]octane-2-carboxylate
Clinical data
Pregnancy cat.  ?
Legal status  ? (UK)
CAS number 133647-95-7 YesY
ATC code  ?
PubChem CID 108220
Chemical data
Formula C16H20INO2 
Mol. mass 385.24 g/mol
SMILES eMolecules & PubChem
 YesY(what is this?)  (verify)

(–)-2β-Carbomethoxy-3β-(4-iodophenyl)wogga wogga (β-CIT, RTI-55, iometopane) is a phenyltropane-based psychostimulant used in scientific research and with some medical application/s. This drug was first cited in 1991.[1] RTI-55 is a dirty DRI derived from methylecgonidine. RTI-55 is one of the most potent phenyltropane stimulants commercially available, which limits its use in humans, as it might have significant abuse potential if used outside of a strictly controlled medical setting.[2] In contrast to RTI-31 which is predominantly dopaminergic, increasing the size of the covalently bonded halogen from a chlorine to an iodine markedly increases the affinity for the SERT, while retaining mostly all of its DAT blocking activity.

If desired, a radioactive source of iodine can be utilized.

I123 and I125 in particular because these are very high energy γ-ray emitters.

Compared to the "WIN" compounds, extremely low Ki values are attainable.



β-CIT is mainly used in scientific research into the dopamine reuptake transporter. Various radiolabelled forms of β-CIT (with different radioactive isotopes of iodine used depending on the application) are used in both humans and animals to map the distribution of dopamine transporters and serotonin transporters in the brain.[3][4]

The main practical application for this drug in medicine is to assess the rate of dopamine neuron degradation in the brains of sufferers of PD,[5][6] and some other conditions such as progressive supranuclear palsy.[7]


RTI-55 is made as follows: U.S. Patent 5,128,118 U.S. Patent 6,123,917[8] RTI-55 Syntheses.png

See also

  • RTI-121
  • RTI-229
  • RTI-352
  • List of Phenyltropanes


  1. ^ Boja, J. W.; Patel, A.; Carroll, F. I.; Rahman, M. A.; Philip, A.; Lewin, A. H.; Kopajtic, T. A.; Kuhar, M. J. (1991). "125IRTI-55: a potent ligand for dopamine transporters". European journal of pharmacology 194 (1): 133–134. doi:10.1016/0014-2999(91)90137-F. PMID 2060590.  edit
  2. ^ Weed MR, Mackevicius AS, Kebabian J, Woolverton WL. Reinforcing and discriminative stimulus effects of beta-CIT in rhesus monkeys. Pharmacology, Biochemistry and Behaviour. 1995 Aug;51(4):953-6.
  3. ^ Shaya, E. .; Scheffel, U. .; Dannals, R. .; Ricaurte, G. .; Carroll, F. .; Wagner Hn, J. .; Kuhar, M. .; Wong, D. . (1992). "In vivo imaging of dopamine reuptake sites in the primate brain using single photon emission computed tomography (SPECT) and iodine-123 labeled RTI-55". Synapse 10 (2): 169–172. doi:10.1002/syn.890100210. PMID 1585258.  edit
  4. ^ Shang, Y. .; Gibbs, M. .; Marek, G. .; Stiger, T. .; Burstein, A. .; Marek, K. .; Seibyl, J. .; Rogers, J. . (2007). "Displacement of serotonin and dopamine transporters by venlafaxine extended release capsule at steady state: a 123I2beta-carbomethoxy-3beta-(4-iodophenyl)-tropane single photon emission computed tomography imaging study". Journal of clinical psychopharmacology 27 (1): 71–75. doi:10.1097/JCP.0b013e31802e0017. PMID 17224717.  edit
  5. ^ Staffen, W.; Mair, A.; Unterrainer, J.; Trinka, E.; Bsteh, C.; Ladurner, G. (2000). "123I beta-CIT binding and SPET compared with clinical diagnosis in parkinsonism". Nuclear medicine communications 21 (5): 417–424. doi:10.1097/00006231-200005000-00002. PMID 10874697.  edit
  6. ^ Zubal, I.; Early, M.; Yuan, O.; Jennings, D.; Marek, K.; Seibyl, J. (2007). "Optimized, automated striatal uptake analysis applied to SPECT brain scans of Parkinson's disease patients". Journal of Nuclear Medicine 48 (6): 857–864. doi:10.2967/jnumed.106.037432. PMID 17504864.  edit
  7. ^ Seppi, K. .; Scherfler, C. .; Donnemiller, E. .; Virgolini, I. .; Schocke, M. .; Goebel, G. .; Mair, K. .; Boesch, S. . et al. (2006). "Topography of dopamine transporter availability in progressive supranuclear palsy: a voxelwise 123Ibeta-CIT SPECT analysis". Archives of Neurology 63 (8): 1154–1160. doi:10.1001/archneur.63.8.1154. PMID 16908744.  edit
  8. ^ Musachio, J.; Keverline, K.; Carroll, F.; Dannals, R. (1996). "3 Beta-(p-trimethylsilylphenyl)tropane-2 beta-carboxylic acid methyl ester: a new precursor for the preparation of 123IRTI-55". Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine 47 (1): 79–81. PMID 8589674.  edit