Synthesis and biological activities of N-Benzoyl-N′-(1,3,4-thiadiazol-2-yl)thioureas

Ten N-benzoyl-N′-(1,3,4-thiadiazol-2-yl)thioureas(3a-3j) were synthesized by addition reactions of 2-amino-1,3,4-thiadiazoles and benzoyl isothiocyanates which prepared by acyl chlorination and acylation of benzoic acids.Tests on biological activities showed that 3a-3d had good regulatory activities on the roots and buds of wheat at the concentration of 10 mg/l.Most of the compounds had obvious antifungal activities on Botrytis cinerea,Colletotrichum orbiculare,Rhizoctonia solani and Pyricularia oryzae at the concentration of 100 mg/l.But all of them had poor fungicidal activity to Fusarium oxysporium.Substituents of the target compounds affected their plant growth regulative activity and fungicidal activity.The effect of structures of the target compounds on fungicidal activity was discussed based on the results of quantum calculations.