Fluorine-18 labeled aldehydes as prosthetic groups for oxime coupling with a FVIIa protein

¹⁸ F-labeled aldehydes can be utilized for oxime coupling with chemically sensitive proteins, such as coagulation factor VII (FVII), if they are sufficiently reactive and can react in an aqueous solvent. New ¹⁸ F-labeled nonvolatile aldehyde prosthetic groups derived from [¹⁸ F]F-Py-TFP and spirocyclic iodonium (III)ylide precursors for late stage ¹⁸ F-labeling were developed. These precursors were characterized, ¹⁸ F-labeled, and compared in reactivity for oxime coupling. Oxime coupling was performed on an amino-oxy modified inhibited factor VII (FVIIai-ONH₂ ) in low concentration to prove the applicability of the proposed method.