Article pubs.acs.org/bc
EGF Receptor-Targeting Peptide Conjugate Incorporating a Near-IR Fluorescent Dye and a Novel 1,4,7-Triazacyclononane-Based 64Cu(II) Chelator Assembled via Click Chemistry Katrin Viehweger,*,† Lisa Barbaro,∥ Karina Pombo García,† Tanmaya Joshi,⊥ Gerhard Geipel,‡ Jörg Steinbach,†,§ Holger Stephan,*,† Leone Spiccia,*,⊥ and Bim Graham*,∥ †
Institute of Radiopharmaceutical Cancer Research and ‡Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf eV, P.O. Box 510119, D-01314 Dresden, Germany § Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany ∥ Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia ⊥ School of Chemistry, Monash University, Clayton, Vic 3800, Melbourne, Australia S Supporting Information *
ABSTRACT: A new Boc-protected 1,4,7-triazacyclononane (TACN)-based pro-chelator compound featuring a “clickable” azidomethylpyridine pendant has been developed as a building block for the construction of multimodal imaging agents. Conjugation to a model alkyne (propargyl alcohol), followed by deprotection, generates a pentadentate ligand, as confirmed by X-ray crystallographic analysis of the corresponding distorted square-pyramidal Cu(II) complex. The ligand exhibits rapid 64 Cu(II)-binding kinetics (>95% radiochemical yield in
