Synthesis of high specific activity (+)- and (-)-6-[18F]fluoronorepinephrine via the nucleophilic aromatic substitution reaction

J Med Chem. 1991 Feb;34(2):767-71. doi: 10.1021/jm00106a043.

Abstract

The first example of a no-carrier-added 18F-labeled catecholamine, 6-[18F]fluoronorepinephrine (6-[18F]FNE), has been synthesized via nucleophilic aromatic substitution. The racemic mixture was resolved on a chiral HPLC column to obtain pure samples of (-)-6-[18F]FNE and (+)6-[18F]FNE. Radiochemical yields of 20% at the end of bombardment (EOB) for the racemic mixture (synthesis time 93 min), 6% for each enantiomer (synthesis time 128 min) with a specific activity of 2-5 Ci/mumol at EOB were obtained. Chiral HPLC peak assignment for the resolved enantiomers was achieved by using two independent methods: polarimetric determination and reaction with dopamine beta-hydroxylase. Positron emission tomography (PET) studies with racemic 6-[18F]FNE show high uptake and retention in the baboon heart. This work demonstrates that nucleophilic aromatic substitution by [18F]fluoride ion is applicable to systems having electron-rich aromatic rings, leading to high specific activity radiopharmaceuticals. Furthermore, the suitably protected dihydroxynitrobenzaldehyde 1 may serve as a useful synthetic precursor for the radiosynthesis of other complex 18F-labeled radiotracers.

Publication types

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

MeSH terms

  • Animals
  • Chemical Phenomena
  • Chemistry
  • Chromatography, High Pressure Liquid
  • Female
  • Fluorine Radioisotopes
  • Heart / diagnostic imaging
  • Myocardium / metabolism
  • Norepinephrine / analogs & derivatives*
  • Norepinephrine / chemical synthesis
  • Norepinephrine / metabolism
  • Papio
  • Stereoisomerism
  • Tomography, Emission-Computed

Substances

  • Fluorine Radioisotopes
  • 6-fluoronorepinephrine
  • Norepinephrine