Palladium(II) complexes of 2-acetylpyridine N(4)-methyl, N(4)-ethyl and N(4)-phenyl-thiosemicarbazones. Crystal structure of chloro(2-acetylpyridine N(4)-methylthiosemicarbazonato) palladium(II). Synthesis, spectral studies, in vitro and in vivo antitumour activity

The reactions of 2-acetylpyridine N(4)-methyl, (HAc4Me), N(4)-ethyl (HAc4Et) and N(4)-Phenyl (HAc4Ph) thiosemicarbazone with palladium(II) were studied. The ligands and the palladium(II) complexes have been characterized by spectroscopic techniques. The structure of [Pd(Ac4Me)Cl] has been determined by single-crystal x-ray diffraction. The protonation constants of HAc4Me and HAc4Et, K-a1 and K-a2, were determined by spectrophotometry, The effect of palladium compounds on DNA synthesis of P388 and L1210 cell cultures is also reported. Some of these compounds increased the life span of mice bearing tumors. (C) 1997 Elsevier Science Inc.