Strain‐Promoted Copper‐Free “Click” Chemistry for 18F Radiolabeling of Bombesin

Click for PET: The GRP-receptor-specific peptide bombesin, which is often used for nuclear imaging of tumors, can be labeled with 18F in a mild and rapid manner by using a copper-free azide–alkyne “click” reaction. A range of azides can be used to provide peptides with different hydrophobicities. The resulting 18F radiopharmaceutical tracers (see scheme) maintain their high affinity for the targeted receptor in vitro in human prostate cancer cells.