Natural products-based insecticidal agents 6. Design, semisynthesis, and insecticidal activity of novel monomethyl phthalate derivatives of podophyllotoxin against Mythimna separata Walker in vivo

Trans-lactone, 4β-substitution, 2β-chlorine substitution, and 4′-methoxy group were the important structural properties of podophyllotoxins for good insecticidal activity.