Rapid Construction of 18 F-Triazolyl-tetrazines through the Click Reaction.

Due to the fast reaction rate, 18 F-labeled tetrazines have been widely applied in positron emission tomography (PET) imaging in cancer research and drug discovery. In this work, several functional 18 F-triazolyl-tetrazines were rapidly obtained through an optimized copper-catalyzed alkyene-azide cycloaddition reaction system in >99% radiochemical conversions. Notably, the commonly used 18 F-labeled azides were isolated through cartridges and directly used for cycloadditions, which greatly simplified the labeling procedure. The assembled triazolyl-tetrazines demonstrated high in vitro stability and reaction kinetics, exhibiting considerable potential for the development of PET agents.