| Summary: | Naturally occurring nootkatone, with reported insecticidal and acaricidal properties, has been used as a lead to generate molecular diversity and, consequently, new insect antifeedant and ixodicidal compounds. A total of 22 derivatives were generated by subjecting this molecule to several reactions including dehydrogenation with the iodine/DMSO system, oxidation with SeO<sub>2</sub>, epoxidation with <i>m</i>CPBA, oxidation or carbon homologations of the α-carbonyl position with TMSOTf (trimethylsilyl trifluoromethanesulfonate) followed by Rubottom and Dess Martin periodane oxidations, condensation with formaldehyde using Yb(OTf)<sub>3</sub> as catalyst and dehydroxilation using the Grieco protocol. The insect antifeedant (against <i>Myzus persicae</i> and <i>Ropaloshysum padi</i>) and ixodicidal (against the tick <i>Hyalomma lusitanicum</i>) activities of these compounds were tested. Compound <b>20</b> was the most active substance against <i>M. persicae</i> and <i>R. padi</i>, and twice more efficient than nootkatone in the antitick test.
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