Substituted benzaldehyde thiosemicarbazone with antiviral activity against poliovirus.

A series of eight benzaldehyde thiosemicarbazone derivatives with a variable number of -OH substituents at different positions on the aromatic ring were prepared and evaluated for in vitro antiviral activity against poliovirus types I, II and III. Some of the compounds significantly inhibited the replication of poliovirus at a mean ED50 of 2, 5.7, 10.5 and 9.7 micrograms/ml. A comparison between chemical structure and biological activity suggests that the inhibitory effect depends on the relative position of the -OH and the thiosemicarbazone group. The compounds possess antiviral action only when the two groups are distant enough to prevent the formation of intramolecular hydrogen bonds.