Annotinolides A–C, Three Lycopodane-Derived 8,5-Lactones with Polycyclic Skeletons from Lycopodium annotinum

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• 作者：Yu Tang ; Juan Xiong ; Jing-Jing Zhang ; Wei Wang ; Hai-Yan Zhang ; Jin-Feng Hu
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：September 2, 2016
• 年：2016
• 卷：18
• 期：17
• 页码：4376-4379
• 全文大小：321K
• 年卷期：0
• ISSN：1523-7052

文摘

Three novel 7,8-seco-lycopodane-derived 8,5-lactones (annotinolides A–C, 1–3) were isolated from Lycopodium annotinum. Their structures were elucidated by spectroscopic methods and single-crystal X-ray diffraction. Compound 1 possesses an unusual cyclopropane ring constructed through a hitherto unknown C-6/C-12 bond. Compound 2 represents the first 7,8-seco-lycopodane-derived alkaloid with a rare cyclobutane ring formed by a new C-12/C-15 linkage, while the C-8/C-15 bond remains. Compound 3 contains an unprecedented 12-spiro-9,12-γ-lactone moiety. Their plausible biosynthetic pathways and antiaggregation effects on amyloid-β_1–42 are also presented.