Design, synthesis, and fungicidal activities of novel piperazine thiazole derivatives containing oxime ether or oxime ester moieties

BACKGROUNDTo study the effect of changing the piperidine ring of oxathiapiprolin on the fungicidal activity, we designed and synthesized novel piperazine thiazole derivatives containing oxime ether or oxime ester moieties, and studied their fungicidal activities against Phytophthora capsici in vitro. RESULTSThese derivatives showed moderate to good fungicidal activities against Phytophthora capsici, two oxime ether derivatives showed higher fungicidal activity in vitro than dimethomorph (EC50 = 0.1331 mu g mL(-1)) and comparable to oxathiapiprolin (EC50 = 0.0042 mu g mL(-1)). Oxime ester derivatives showed significantly reduced activities compared with oxime ether derivatives. Most of these derivatives showed broad-spectrum fungicidal activity against the other eight kinds of fungi. Moreover, four derivatives exhibited good antifungal activities in vivo against Phytophthora capsici, Pseudoperonospora cubensis, and Phytophthora infestans. The hyphae morphology study showed that compound 10d might cause mycelial abnormalities of Phytophthora capsici. CONCLUSIONThe activity of 10b against Phytophthora infestans was better than that of mandipropamid, and compound 10d exhibited higher fungicidal activities against Pseudoperonospora cubensis and Phytophthora infestans than mandipropamid. These two derivatives emerged as promising candidates for antifungal drugs. (c) 2023 Society of Chemical Industry.

Automated summary

This study designed and synthesized a series of piperazine thiazole derivatives containing oxime ether or oxime ester moieties and investigated their fungicidal activities. The results showed that these derivatives exhibited moderate to good fungicidal activities against Phytophthora capsici, with two oxime ether derivatives showing higher activity than dimethomorph and comparable to oxathiapiprolin. Oxime ester derivatives showed reduced activities. Most of these derivatives showed broad-spectrum fungicidal activity against other fungi, and four derivatives showed good antifungal activities against various pathogens. Compound 10d might cause mycelial abnormalities of Phytophthora capsici.