Synthesis, spectral studies and screening for amoebicidal activity of new palladium(II) complexes derived from thiophene-2-carboxaldehyde thiosemicarbazones

In view of the antiamoebic properties observed for many thiophene-2-carboxaldehyde thiosemicarbazones, a series of N4-substituted thiosemicarbazones metal complexes derived from thiophene-2-carboxaldehyde was prepared for evaluation against Entamoeba histolytica. Reaction of thiophene-2-carboxaldehyde with cycloalkylaminothiocarbonylhydrazines having different amines gave the corresponding thiosemicarbazones. Reaction of latter with [Pd(DMSO)2Cl2] gave requisite palladium thiosemicarbazone complexes of the type [Pd(TSC)Cl2] (where TSC=thiosemicarbazones). Screening of antiamoebic activity of these compounds was assayed in vitro against (HM-1:1MSS) strain of E. histolytica. Enhancement of antiamoebic resulted from introducing palladium metal in the thiosemicarbazone moiety. Among the studied compounds, [Pd(2-TCA-1,2,3,4-THQTSC)Cl2] (2a) showed better activity.