Synthesis of a new chelating agent derived from phenylenediamine for application in radioimmunotherapy

We report the synthesis of a new diethylenetriaminepentaacetic acid (DTPA) analogue, Ph-DTPA, possessing an aromatic rigid skeleton. This precursor of a bifunctional chelating agent was synthesized by elaboration of the intermediate N-(o-aminophenyl)ethylenediamine and obtained in five steps with an overall yield of 42%. Preliminary complexation studies between Ph-DTPA and 153Sm has been carried out.