Inhibition of the RNA dependent DNA polymerase and the malignant transforming ability of Rous sarcoma virus by thiosemicarbazone-transition metal complexes

Several thiosemicarbazone-metal complexes inhibit the RNA dependent DNA polymerase and the transforming ability of Rous sarcoma virus. Some complexes are equally as active as the free ligand whereas the activity of others is greatly enhanced. The 2-formyl pyridine thiosemicarbazone copper (II) complex is the most potent compound of this class that we tested. Some copper complexes of salicylaldehyde derivatives are very active also, particularly N-n-butyl, N-n-hexyl and N-benzylsalicylaldimine; no nickel complex of any salicylaldehyde compound is active. In addition, other metal ligands, such as dithizone, diacetyl bis (mercaptoethylimine), N-butyl thiocarbamate, 0,0′ dimethyl dithiophosphate, potassium dithiooxalate, and cis-Pt^II(NH₃)₂Cl₂ were tested with varying results.