Synthesis and bioactivity of novel sulfonazoline analogues

A series of 20 novel acylsulfonimide derivatives 3a-3t were synthesized from phthalic anhydride, sulfonamide and butyl chloroformate by means of active substructure splicing. Their structures were confirmed by ¹H NMR, ¹³C NMR and high resolution mass spectrometry. The fungicidal and herbicidal activities of the target compounds were determined using the mycelial growth rate method and the stem and leaf spray method, respectively. The results of fungicidal activity showed that most of the compounds had good inhibitory effects against Sclerotinia sclerotiorum, Colletotrichum camalliae, Sclerotium rolfii and Phytophthora capsici at 50 mg/L. The inhibition rates of 3f, 3n and 3q against S. sclerotiorum were 63.98%, 79.56% and 77.83%, respectively, which were better than that of the commercial asulox (58.78%). The EC₅₀ values of compound 3q against C. camalliae and S. sclerotiorum were 21.57 mg/L and 10.49 mg/L, respectively, which were better than asulox. The herbicidal activity results showed that, the fresh weight control effect of compound 3a against Echinochloa crus-galli was 52.48% at 150 mg/L, which was lower than asulox (71.68%). The novel compounds synthesized in this study displayed fungicidal activities, which can provide reference for the study of biological activities of novel acyl sulfonimide derivatives.