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-(4methoxyphenyl)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.

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A series of saccharin derivatives containing 2-aminothiazole scaffold were designed, synthesized, and characterized by 1 H NMR, 13 C NMR, and HRMS. The fungicidal activities of these novel compounds against Botrytis cinerea, Curvularia lunata, and Rhizoctonia solani were evaluated. The results indicated that N-(4- ((1,1-dioxido-3-oxobenzo[d]isothiazol-2(3H)-yl) methyl) thiazol-2-yl) acrylamide (HST3) displayed potential fungicidal activities against C. lunata, and R. solani with IC 50 values of 15.0 mg/L and 12.9 mg/L respectively, which possessed higher fungicidal activity than commercial products hymexazol and amicarthiazol.Moreover, N-(4- ((1,1-dioxido-3oxobenzo[d]isothiazol-2(3H)-yl) methyl) thiazol-2-yl)-4-methoxybenzamide (HST9) possessed an IC 50 value of 1.1 mg/L against B. cinerea, superior to hymexazol, amicarthiazol, and carboxin. Besides, the superficial structure-activity relationship was discussed. Furthermore, molecular docking result suggest that SDH enzyme might be one of the action targets of title compounds.