Structure-Activity Study of S-n-Butyl S'-p-tert-Butylbenzyl N-3-Pyridyldithiocarbonimidate (S-1358, Denmert^®) and Its Derivatives

Abstract

Fungicidal activities of S-alkyl S'-p-substituted benzyl N-3-pyridyldithiocarbonimidates toward Coniothyrium diplodiella, Scleotinia sclerotiorum (on agar medium) and Sphaerotheca fuliginea (on pot test) were shown. The activities varied with the change of the S-alkyl group and were maximized at certain numbers of carbon atoms.
A different pattern was observed in the activity toward S. fuliginea when the carbon number was 8 or more. Bulkiness of the S-alkyl group also appeared to influence the activities. The steric factor of the p-alkyl substituents mainly influenced the activity toward S. fuliginea up to the tert-butyl analog. The activities toward C. diplodiella and S. sclerotiorum increased with the increase in the bulkiness and the hydrophylicity of the p-substituent. RM values were determined on reversed phase TLC and the structure-activity correlations were analyzed against hydrophobic (RM), electronic (σ) and steric (Es) factors on 34 compounds.