Gelsecorydines A–E, Five Gelsedine–Corynanthe-Type Bisindole Alkaloids from the Fruits of Gelsemium elegans

作者：Ni-Ping Li, Miao Liu, Xiao‐Jun Huang, Xue-Ying Gong, Wei Zhang, Min-Jing Cheng, Wen‐Cai Ye, Lei Wang · 发表于：The Journal of Organic Chemistry · 年份：2018 · DOI：10.1021/acs.joc.8b00736 · 被引用次数：44 · 研究领域：Alkaloids: synthesis and pharmacology、Traditional and Medicinal Uses of Annonaceae、Chemical synthesis and alkaloids

Five monoterpenoid bisindole alkaloids with new carbon skeletons, gelsecorydines A-E (1-5), together with their biogenetic precursors were isolated from the fruits of Gelsemium elegans. Compounds 1-5 represent the first examples of heterodimeric frameworks composed of a gelsedine-type alkaloid and a modified corynanthe-type one. Notably, compound 2 featured an unprecedented caged skeleton with a 6/5/7/6/5/6 heterohexacyclic ring system, which possessed a pyridine ring that linked the two monomers. Their structures and absolute configurations were elucidated by spectroscopic analysis, X-ray diffraction, and electronic circular dichroism (ECD) calculation. A plausible biosynthetic pathway for compounds 1-5 is proposed. Compounds 1, 3, 4, and 5 exhibited a significant inhibitory effect against nitric oxide (NO) production in macrophages.