Synthesis, Structure, and Antitumour Testing of Platinum(II) and Palladium(II) Complexes of 1,6‐Diaminotetrahydropyrrolo[2,3‐b]pyrrole‐2,5(1H,4H)‐dione

The syntheses of the platinum(II) and palladium(II) complexes of 1,6‐diaminotetrahydropyrrolo[2,3‐b]pyrrole‐2,5(1H,4H)‐dione (3) are described. These compounds contain a six‐membered chelate ring with four nitrogen atoms. An X‐ray diffraction study of the palladium(II) complex [Pd(3)Cl₂] shows a distorted “sofa” conformation for this chelate ring. Both complexes exhibited in the ¹H‐NMR spectrum an ABgem system for the amino protons. In vitro ICL₅₀ and ICT₅₀ and in vivo antitumour activities have been determined for these products. The corresponding dicarboxylato complexes have been obtained by the reaction of the platinum(II) complex [Pt(3)Cl₂] with silver sulfate followed by the addition of barium hydroxide and oxalic, malonic, hydroxymalonic, and 1,1‐cyclobutanedicarboxylic acid.