Rapid and Efficient Radiosyntheses of meta-Substituted [18F]Fluoroarenes from [18F]Fluoride Ion and Diaryliodonium ­Tosylates within a Microreactor

Authors

  • Joong-Hyun Chun,

    1. Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health 10 Center Drive, Building 10, Room B3 C346A, Bethesda, MD 20892, USA, Fax: +1-301-480-5112
    Search for more papers by this author
  • Shuiyu Lu,

    1. Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health 10 Center Drive, Building 10, Room B3 C346A, Bethesda, MD 20892, USA, Fax: +1-301-480-5112
    Search for more papers by this author
  • Victor W. Pike

    1. Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health 10 Center Drive, Building 10, Room B3 C346A, Bethesda, MD 20892, USA, Fax: +1-301-480-5112
    Search for more papers by this author

Abstract

Effective methods for the introduction of the short-lived positron-emitter fluorine-18 (t1/2 = 109.7 min) at high specific radioactivity into fluoroarenes are valuable for the development of radiotracers for molecular imaging with positron emission tomography. We have explored the scope of the radiofluorination of diaryliodonium salts with no-carrier-added (NCA) [18F]fluoride ion for the preparation of otherwise difficult to access meta-substituted [18F]fluoroarenes. A microfluidic reaction platform was used to establish optimal radiochemical yields. Rapid, high yielding and selective radiofluorinations were achieved in unsymmetrical diaryliodonium tosylates (ArI+Ar′TsO), in which Ar carried either a meta electron-withdrawing (CN, NO2, CF3) or electron-donating (Me or MeO) group, and in which the partner aryl group (Ar′) was relatively electron-rich, such as Ph, 3-MeC6H4, 4-MeOC6H4, 2-thienyl, or 5-Me-2-thienyl. The radiofluorination of appropriate diaryliodonium tosylates is therefore a generally useful method for the preparation of simple [18F]m-fluoroarenes ([18F]ArF).

Ancillary