Synthesis and insecticidal activities of 5-deoxyavermectin B2a oxime ester derivatives.

Three series of avermectin B2a oxime ester derivatives were synthesized using avermectin B2a as starting material. All of the compounds were characterized by H NMR, C NMR, and HRMS. Bioassay results indicated that some of the derivatives (8b, 8c, 8d, 8f, 11k, 11l, 14c, 14j) showed potent insecticidal activities against , , or . As shown by initial insecticidal activity data, compound 8d showed excellent activities (>90%) against and , which were more potent than that of avermectin B2a. Compound 8d might be a lead compound for designing new avermectin B2a derivatives.