Radioiodinated p-iodoclonidine: a high-affinity probe for the alpha 2-adrenergic receptor

J Med Chem. 1987 Jul;30(7):1241-4. doi: 10.1021/jm00390a021.

Abstract

The chemical synthesis of 2-[(2,6-dichloro-4-iodophenyl)imino]imidazolidine (PIC) and its radioiodinated analogue [125I]PIC is described. PIC was synthesized from 2,6-dichloroaniline in five synthetic steps. This agent displayed a high affinity for the alpha 2-adrenergic receptor (IC50 = 1.5 nM) in competitive binding assays conducted with purified human platelet plasma membrane fractions. For the synthesis of radioiodinated PIC the triazene intermediate 11 was synthesized from 2,6-dichloro-4-nitroaniline in five synthetic steps. Acid-catalyzed decomposition of 11 with no-carrier-added Na125I afforded high specific activity [125I]PIC. In view of its high affinity for the alpha 2-adrenergic receptor, [125I]PIC is a potentially useful probe for studies in adrenergic pharmacology.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Affinity Labels / chemical synthesis*
  • Affinity Labels / metabolism
  • Clonidine / analogs & derivatives*
  • Clonidine / chemical synthesis
  • Clonidine / metabolism
  • Humans
  • Iodine Radioisotopes
  • Receptors, Adrenergic, alpha / metabolism*

Substances

  • Affinity Labels
  • Iodine Radioisotopes
  • Receptors, Adrenergic, alpha
  • 4-iodoclonidine
  • Clonidine