Synthesis and insecticidal activity of new oxime derivatives of podophyllotoxin-based phenazines against Mythimna separata Walker.

To discover new natural-product-based insecticidal agents, a series of novel oxime derivatives of podophyllotoxin-based phenazines modified in the C, D and E rings of podophyllotoxin were prepared and tested as insecticidal agents against the pre-third-instar larvae of oriental armyworm, Mythimna separata (Walker) in vivo at 1 mg/mL. The steric configuration of IIIc was unambiguously confirmed by single-crystal X-ray diffraction analysis. Compounds IIIa-d, and IIIi exhibited an equal or higher insecticidal activity than toosendanin.