Synthesis and Fungicidal Activity of Simple Structural 1,3-Thiazolidine-2-Thione Derivatives

A series of simple structural 1,3-thiazolidine-2-thione derivatives with various substituents on the S-, N-, 4-, and 5-positions was synthesized with high yields from various vicinal amino alcohols via two steps and screened for their antifungal activity. Bioassay results reveal that some thiazolidine-2-thione derivatives show strong antifungal activities against P. capsici, G. zeae, S. sclerotiorum, A. alternata, B. cinerea, or R. solani. The SAR analysis indicates that N-acyl substituted and 4-alkyl substituents can enhance the antifungal activity. Notably, 4-isopropyl-N-propionylthiazoldine-2-thione shows excellent activity against B. cinerea and G. zeae with IC50 values at 3.7 mu g/mL and 6.5 mu g/mL, respectively, and 4-isobutyl-N-propionylthiazoldine-2-thione shows remarkable fungicidal activity against R. solani, S. sclerotiorum, and G. zeae with IC50 values at 1.0 mu g/mL, 12.1 mu g/mL, and 11.0 mu g/mL, respectively.