Synthesis of 18F-labeled Neurotensin(8-13) via Copper-Mediated 1,3-Dipolar [3+2]Cycloaddition Reaction

The copper(I)-mediated 1,3 dipolar [3+2]cycloaddition between terminal alkynes and azides, also referred to as click-chemistry, was used to synthesize a 18F-labeled neurotensin(8-13) (NT(8-13)). 4- [18F]Fluoro-N-(prop-2-ynyl)benzamide [18F]1 as novel terminal alkyne building block could successfully be coupled with azide-functionalized NT(8-13) 4 to give the corresponding 18F-labeled NT(8-13) derivative [18F]5 in 66% yield as determined by radio-HPLC. The in vitro binding affinity of NT(8-13) derivative [19F]5 was determined to be 66 nM (IC50 ).