Site-Specific Addition of an 18F-N-methylaminooxy Containing Prosthetic Group to A Vinylsulfone Modified Peptide

AbstractNumerous strategies employing prosthetic groups for the radiosynthesis of 18F‐fluorinated peptides for positron emission tomography have been investigated in recent years. We have previously reported a novel [18F]prosthetic group bearing the N‐methylaminooxy functionality capable of reacting in a site‐selective manner with peptides functionalized with Michael‐acceptors. In a further extension of this methodology we demonstrate that O‐[2‐(2‐[18F]fluoroethoxy)ethyl]‐N‐methyl‐N‐hydroxylamine, [18F]4, reacts chemoselectively with a vinylsulfone functionalized peptide. The conjugation yields were studied with respect to reaction time, level of radioactivity, peptide concentration and purity of the [18F]prosthetic group used in the conjugation reaction. Incubation at 70°C gave conjugation yields of around 80% with high radiochemical purity after 70 min at pH 5 in acetate buffer. Copyright © 2009 John Wiley & Sons, Ltd.