Synthesis and insecticidal activities of new ether-derivatives of Celangulin-V.

In order to find new biorational pesticides, eight new 6-substituted ether derivatives of Celangulin-V were synthesized. The structures were confirmed by IR, 1H NMR and 13C NMR spectroscopic and HRMS analyses. The insecticidal activities of these compounds were tested against third-instar larvae of Mythimna separata. Four derivatives (b, c, f, g) showed higher insecticidal activities than Celangulin-V, with KD50 values of 135.9, 101.33, 169.0 and 219.2 microg x g-1, respectively. However, two compounds (a, d) showed lower insecticidal activities and two (e, h) no activity. The results suggest that C-6 substitutions in these compounds are very important for their insecticidal activities. The insecticidal activities of the derivatives with two or three carbon substitutions at C-6 are higher than that of Celangulin-V showing that this compound has the potential to be a lead structure for semi-synthetic, green insecticides.