Evaluating N-difluoromethyltriazolium triflate as a precursor for the synthesis of high molar activity 18 Ffluoroform

• Published in: Journal of labelled compounds & radiopharmaceuticals Vol. 64; no. 12; p. 466
• Main Authors: Pees, Anna, Vosjan, Maria J W D, Chai, Jin Young, Cha, Hyojin, Chi, Dae Yoon, Windhorst, Albert D, Vugts, Danielle J
• Format: Journal Article
• Language: English
• Published: 01-10-2021
• ISSN: 1099-1344; 1099-1344
• DOI: 10.1002/jlcr.3939

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 [18 F]trifluoromethylation building block [18 F]fluoroform with high molar activity was investigated. The triazolium precursor was reacted under various conditions with [18 F]fluoride, providing [18 F]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 [18 F]fluoroform synthesis, the triazolium precursor is a valuable alternative to already known precursors.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 [18 F]trifluoromethylation building block [18 F]fluoroform with high molar activity was investigated. The triazolium precursor was reacted under various conditions with [18 F]fluoride, providing [18 F]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 [18 F]fluoroform synthesis, the triazolium precursor is a valuable alternative to already known precursors.