Fig. 2: Synthesis of 15N-labeled TPA derivatives.

The key intermediate in the synthesis is [15N]phthalimde (1), conveniently prepared by heating a mixture of phthalic anhydride and [15N]ammonium acetate.

The key intermediate in the synthesis is [15N]phthalimde (1), conveniently prepared by heating a mixture of phthalic anhydride and [15N]ammonium acetate.