Natural products-based insecticidal agents 20. Design, synthesis and insecticidal activity of novel honokiol/magnolol azo derivatives

Honokiol and magnolol are small-molecule polyphenols isolated from the barks of Magnolia officinalis. To discover novel natural-product-based pesticidal agents, a series of honokiol/magnolol azo derivatives were prepared by structural modification of honokiol or magnolol. Their insecticidal activity was evaluated at 1 mg/mL against the pre-third-instar larvae of oriental armyworm (Mythimna separata Walker), a typical lepidopteran pest. Among all derivatives, 5m and 6k exhibited more promising insecticidal activity with the final mortality rates greater than 60%, when compared with their precursors (honokiol and magnolol) and the positive control, toosendanin. (C) 2015 Elsevier B.V. All rights reserved.