Natural-Product-Based Insecticidal Agents 16. Semisynthesis of C7-Oxime Sulfonate Ester Derivatives of Obacunone as Insecticidal Agents against Mythimna separata Walker

A series of novel C7-oxime sulfonate ester derivatives of obacunone (3a-f) were synthesized.Their insecticidal activity was also evaluated at the concentration of 1 mg/mL against the pre-third-instar larvae of oriental armyworm (Mythimna separata Walker), a typical lepidopteran pest.Especially C7-oxime p-ethylphenylsulfonate ester of obacunone (3d) exhibited more potent insecticidal activity than their precursor obacunone and toosendanin (a positive control).Without agrochemicals, 30% of the world's crops would be lost before they were harvested, 1 therefore, the routine use of a wide variety of synthetic insecticides in agriculture is still the most effective method for controlling insect pests.However, the repeat application of those agrochemicals over the years has resulted in the development of resistance in insect pest populations and environmental problems. 2,3[6] Obacunone (1, Figure 1) was isolated from many species of plants such as Citrus and Dictamnus angustifolius. 7Compound 1 showed many medicinal activities such as antiproliferative, 8 anticancer, [9][10][11] antimalarial, 12 and antioxidant activities. 13On the other hand, compound 1 also displayed interesting NH 2 OH HCl EtOH/Py O O O O O O O 1