A new, simple, high-yield synthesis of "no-carrier-added" 11C-labelled DMO

This paper describes a fast (20 min), convenient, and high yield synthesis of "no-carrier-added" 11C-labelled 5,5-dimethyloxazoladine-2,4-dione (DMO). During the synthesis [11C]phosgene is reacted in situ with 2-hydroxy-2-methylpropionamide in the presence of KOH for 20 min in a -5 degrees C bath and then for 5 min at room temperature. Filtration through a reverse-phase (C18) Sep-Pack column purifies the final product. This synthesis yields about 40 mCi of 11C-labelled DMO (radiochemical yield 40-60%) with a chemical purity exceeding 98% and a radiochemical purity exceeding 99%. The specific activity at the end of the synthesis is 80 Ci/mmol.