10.1021/acs.jafc.5b02036.s001 Rong Wang Rong Wang Xiaoyan Zhi Xiaoyan Zhi Jie Li Jie Li Hui Xu Hui Xu Synthesis of Novel Oxime Sulfonate Derivatives of 2′(2′,6′)-(Di)chloropicropodophyllotoxins as Insecticidal Agents American Chemical Society 2015 podophyllotoxin compounds 4 c chlorine compound 5 f introduction oxime sulfonate derivatives insecticidal activity Novel Oxime Sulfonate Derivatives NMR picropodophyllotoxin Di HRMS 2015-08-05 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Synthesis_of_Novel_Oxime_Sulfonate_Derivatives_of_2_2_6_Di_chloropicropodophyllotoxins_as_Insecticidal_Agents/2144434 To discover novel natural-product-based pesticidal agents, we prepared a series of oxime sulfonate derivatives of 2′(2′,6′)-(Di)­chloropicropodophyllotoxins by structural modification of podophyllotoxin. Their structures were well-characterized by proton nuclear magnetic resonance (<sup>1</sup>H NMR), high-resolution mass spectrometry (HRMS), optical rotation, and melting point. Moreover, the key steric structure of compound <b>5f</b> was unambiguously determined by single-crystal X-ray diffraction. Additionally, 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, compounds <b>4c</b>, <b>5c</b>, and <b>5d</b> exhibited more promising insecticidal activity, with the final mortality rates greater than 60%, when compared to their precursor podophyllotoxin and the positive control, toosendanin. It demonstrated that introduction of the chlorine atom at the C-2′ or C-2′,6′ position on the E ring of picropodophyllotoxin or oxime sulfonate derivatives of picropodophyllotoxin was important for the insecticidal activity and introduction of a halogen (e.g., fluorine, chlorine, or bromine) atom-substituted phenylsulfonyl group on the oxime fragment of 2′(2′,6′)-(di)­chloropicropodophyllones could lead to more promising compounds.