Design, Synthesis and Fungicidal Activity of Novel 2‐aryl‐thiazole Derivatives Containing Saccharin Motif

Abstract A series of novel 2‐aryl‐thiazole derivatives containing saccharin were designed and synthesized by a facile method, and their structures were characterized by 1 H NMR, 13 C NMR and HMRS. Biological tests indicated that the parts of 2‐aryl‐thiazole derivatives possess potent fungicidal activities against Sclerotinia sclerotiorum , Botrytis cinerea , and Alternaria altanata . Especially, N ‐((2‐(4‐chlorophenyl)thiazol‐4‐yl)methyl)‐4‐(1,1‐dioxido‐3‐oxobenzo[d]isothia‐zol‐2(3H)‐yl)butanamide ( 7 p ) displays inhibition rates of 49.2 % and 41.9 % at a concentration of 10 mg/L against S. sclerotiorum and B. cinerea respectively, while 2‐(1,1‐dioxido‐3‐oxobenzo[d]isothiazol‐2(3H)‐yl)‐ N ‐((2‐(4‐methoxyphenyl)thiazol‐4‐yl)methyl)acetamide ( 7 f) shows an inhibition rate of 53.3 % at a concentration of 10 mg/L against A. altanata . Furthermore, the structure‐activity relationship was discussed. It suggested that the 2‐aryl‐thiazole group can be considered as a precursor structure for further design of fungicides.