Evaluating N-difluoromethyltriazolium triflate as a precursor for the synthesis of high molar activity [18F]fluoroform

Anna Pees, Maria J. W. D. Vosjan, Jin Young Chai, Hyojin Cha, Dae Yoon Chi, Albert D. Windhorst, Danielle J. Vugts

Research output: Contribution to JournalArticleAcademicpeer-review

2 Citations (Scopus)


The trifluoromethyl group is a prominent motif in biologically active compounds and therefore of great interest for the labeling with the positron emitter fluorine-18 for positron emission tomography (PET) imaging. Multiple labeling strategies have been explored in the past; however, most of them suffer from low molar activity due to precursor degradation. In this study, the potential of 1-(difluoromethyl)-3-methyl-4-phenyl-1H-1,2,3-triazol-3-ium triflate as precursor for the synthesis of the [18F]trifluoromethylation building block [18F]fluoroform with high molar activity was investigated. The triazolium precursor was reacted under various conditions with [18F]fluoride, providing [18F]fluoroform with radiochemical yields (RCY) and molar activities (Am) comparable and even superior with already existing methods. Highest molar activities (Am = 153 ± 14 GBq/μmol, dc, EOS) were observed for the automated procedure on the Neptis® perform module. Due to its easy handling and good RCY and Am in the [18F]fluoroform synthesis, the triazolium precursor is a valuable alternative to already known precursors.
Original languageEnglish
Pages (from-to)466-476
Number of pages11
JournalJournal of Labelled Compounds and Radiopharmaceuticals
Issue number12
Early online date2021
Publication statusPublished - Oct 2021


  • [ F]fluoroform
  • [ F]trifluoromethylation
  • fluorine-18
  • high molar activity
  • triazolium precursor

Cite this