J Agric Food Chem. 2015 Aug 5;63(30):6668-74. doi: 10.1021/acs.jafc.5b02036. Epub 2015 Jul 22.
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 ((1)H NMR), high-resolution mass spectrometry (HRMS), optical rotation, and melting point. Moreover, the key steric structure of compound 5f 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 4c, 5c, and 5d 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.
为了发现新型天然产物农药，我们通过结构修饰鬼臼毒素，制备了一系列肟磺酸酯衍生物。这些化合物的结构通过质子核磁共振谱（1H NMR）、高分辨率质谱（HRMS）、旋光度和熔点得到了很好的表征。此外，化合物 5f 的关键空间结构通过单晶 X 射线衍射得到了明确的确定。此外，还在 1mg/mL 浓度下评估了它们对三龄前东方粘虫（Mythimna separata Walker）幼虫的杀虫活性，东方粘虫是一种典型的鳞翅目害虫。在所有衍生物中，化合物 4c、5c 和 5d 的杀虫活性更为显著，终死亡率均高于 60%，优于其前体鬼臼毒素和阳性对照川楝素。这表明在鬼臼毒素 E 环的 C-2'或 C-2'、6'位引入氯原子，或在 picropodophyllotoxin 的肟磺酸酯衍生物的肟片段上引入卤素（如氟、氯或溴）取代的苯磺酰基对于杀虫活性很重要，引入 2'（2'、6'）-二氯鬼臼毒素的肟片段上的卤素（如氟、氯或溴）取代的苯磺酰基可以得到更有前途的化合物。
