Rapid synthesis of aliphatic amides by reaction of carboxylic acids, Grignard reagent and amines: application to the preparation of [C-11]amides

Aliphatic amides have been prepared in moderate to good yields (30-70%) by treatment in THF of magnesium halide carboxylates with amines in the presence of 2.5 equivalents of alkylmagnesium halide. The reaction is rapid (<30 min) and has been successfully applied to the synthesis of amides labelled with carbon-ii (beta(+), t(1/2): 20.4 min). [C-11]Aliphatic amides have been obtained in 15-60% radiochemical yields [decay corrected to end of bombardment (EOB), 5 min amidation reaction time].