Imaging agents for myeloperoxidase

The myeloperoxidase (MPO) inhibitors 1 and 2 were prepared as their isotopologues with carbon-14, carbon-13, and nitrogen-15 or tritium with high specific activity and purity. Starting from potassium [14C]cyanide or [14C]formate provided metabolically stable 14C-labels on [14C]-1 and [14C]-2. Catalytic hydrogenation was used for the preparation of [3H]-2, giving multiple enriched positions as shown by 3H NMR. 1 and 2 are promising in vitro and in vivo imaging radioligands and have the potential to provide key information with regard to MPO expression, function, stoichiometry, and pharmacology.