From [11C]CO2 to [11C]amides: a rapid one-pot synthesis via the Mitsunobu reaction.

A novel amide synthesis methodology is described using amines, CO2 and Grignard reagents and Mitsunobu reagents. The method was applied to carbon-11 radiochemistry to label amides using cyclotron-produced [11C]CO2. The synthetic utility of the one-pot labelling methodology was demonstrated by producing [11C]melatonin. The incorporation of [11C]CO2 into [11C]melatonin was 36% - determined by radioHPLC 2 min post [11C]CO2 delivery.