Antifungal activities of mono- and di-SCCl3 substituted compounds: Structure-activity correlations

The mono- and di-N-SCCl₃ substituted derivatives of lactams, cyclic urea, 5,5-diphenylhydantoin and 5-ethyl-5-phenylbarbituric acid were synthesized. Many of these compounds have not been reported previously. The antifungal activities were determined by spore germination method using Stemphylium sarcinaeforme, Monilinia fructicola, Helminthosporium maydis and Alternaria solani. Among the lactam and cyclic urea derivatives studied 1,3-bis(trichloromethylthio)-2-imidazolidinone appears to be the most active compound against S. sarcinaeforme, and has activity slightly below those of the commercial products captan and folpet. Among the diphenylhydantoin and phenobarbital derivatives the mono-SCCl₃ compounds appear to be more potent than the disubstituted compounds in most of the cases examined, but they are not as active as the imidazolidinone derivative. The antifungal activity appears to be highly dependent on the lipophilic character as measured by the 1-octanol/water partition coefficient. Since the bis-SCCl₃ compounds are less potent than the mono-substituted compounds in both of the series of compounds studied, it is evident that the whole molecule rather than any decomposition products of the N-SCCl₃ moiety is responsible for the fungitoxicity.