Effect of Heterocyclic and Other Thiosemicarbazones on Vaccinia Infection in the Mouse

Abstract

Summary: Thiosemicarbazones containing benzene, thiophene, pyridine, quinoline or isatin groups have been demonstrated to protect mice against vaccinia virus. Protection is obtained when the virus is given by the cerebral route and compounds fed in the diet. The =N-NH-CS-NH2 group, as such, appears to be essential for antivaccinal activity. Semicarbazones of benzaldehyde, 2-thenaldehyde, cinchoninaldehyde and isatin were devoid of protective capacity. The presence of an aldehyde structure with attachment of the thiosemicarbazone moiety to the aldehyde carbon atom contributes to antiviral capacity but is not essential for this property. Substitutions on the aldehyde carbon atom reduced or abolished protective action of compounds. Substitution in the ring protion of the molecule produced the same result except in p-nitro and o-methoxy benzaldehyde and 5-chloro, 5-bromo and 3-methyl-2-thenaldehyde derivatives. Thiosemicarbazones with high antivaccinal activity in mouse embryonic tissues may fail to protect mice against the virus.