[Synthesis of radioactively labelled tetroxoprim (author's transl)].
Synthesis of radioactively labelled 2,4-diamino-5-[3,5,-dimethoxy-4-(2-methoxyethoxy)]-benzylpyrimidine (tetroxoprim) as needed for pharmacokinetic studies, is described. Commercial [14C]-guanidine hydrochloride was used as radioactive label.