[Synthesis of radioactively labelled reproterol hydrochloride (author's transl)].

Synthesis of radioactively labelled 7-(3-[2-(3,5-dihydroxy-phenyl)-2-hydroxy-ethylamino]-propyl)-theophylline (reproterol) as needed for pharmacokinetic examinations, is described. The 14C-malonic diethyl ester was proven to be the suitable starting compound. The synthesis of the tritium-labelled reproterol is briefly described.