Radiosynthesis and reactivity of N -[ 11 C]methyl carbamoylimidazole.

N -Methyl carbamoylimidazole is a safe and practical alternative to methyl isocyanate for carbamoylation reactions. We have developed a new chemical route for its synthesis from methyl iodide and applied this to the synthesis of N -[11 C]methyl carbamoylimidazole as a new [11 C]synthon to radiolabel biomolecules for PET imaging research. N -[11 C]methyl carbamoylimidazole was prepared from [11 C]methyl iodide in 70-74% radiochemical yield (decay corrected) and can be used in situ for further reaction without purification. The reactivity of N -[11 C]methyl carbamoylimidazole was demonstrated in a series of [11 C]carbamoylation reactions.