Synthesis of N1'-([11C]methyl)naltrindole ([11c]MeNTI): A radioligand for position emission tomographic studies of delta opioid receptors

J. R. Lever, C. M. Kinter, H. T. Ravert, J. L. Musachio, W. B. Mathews, R. F. Dannals

Research output: Contribution to journalArticlepeer-review


A delta opioid receptor antagonist, N1'-methylnaltrindole (MeNTI), has been labeled with carbon-11. The precursor for radiolabeling was prepared in 71% yield by benzylation of the phenolic moiety of naltrindole. Alkylation of the indole nitrogen using [11C]iodomethane and aqueous tetra (n-butyl)ammonium hydroxide at 80 °C in dimethylformamide followed by hydrogenolysis (H2, 10% Pd-C) of the benzyl protecting group gave [11C]MeNTI. The average (n = 10) time for radiosynthesis, HPLC purification and formulation was 24 min from end-of-bombardment. [11C]MeNTI of high radiochemical purity was obtained at end-of-synthesis with an average specific activity of 2050 mCi/μmol and radiochemical yield, based on [11C]iodomethane, of 6%.

Original languageEnglish (US)
Pages (from-to)137-145
Number of pages9
JournalJournal of Labelled Compounds and Radiopharmaceuticals
StatePublished - Dec 1 1994


  • Carbon-11
  • Delta opioid receptor
  • Naltrindole
  • Positron emission tomography
  • Radiotracer

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Radiology Nuclear Medicine and imaging
  • Drug Discovery
  • Spectroscopy
  • Organic Chemistry

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