Electrophilic addition of chlorine monofluoride for PET tracers.
Palavras-chave
Resumo
OBJECTIVE
We have studied the utility of [(18)F]ClF electrophilic addition to the carbon-carbon double bond of analogues of a model positron emission tomography (PET) tracer, [(18)F]EF5. The consequence of simultaneous chlorine/fluorine addition on lipophilicity and biological activity of the molecule is evaluated.
METHODS
Post-target produced [(18)F]F2 was reacted with Cl2 to produce [(18)F]ClF, which was used in electrophilic addition.
RESULTS
[(18)F]ClF was produced and used to label chlorinated analogues of [(18)F]EF5. The chlorinated analogues, [(18)F]EF4Cla and [(18)F]EF4Clb, were synthesized simultaneously. The in vivo uptake of the analogues compared well with [(18)F]EF5 uptake in tumor-bearing mice.
CONCLUSIONS
[(18)F]ClF is a suitable labeling reagent for electrophilic addition to double bonds of PET tracers. The results show that the modification of the pentafluoro group of [(18)F]EF5 by monofluorine-for-chlorine exchange affected the lipophilicity, but the hypoxia avidity of these molecules was not apparently altered.
