Sweritranslactones A-C: Unusual Skeleton Secoiridoid Dimers via [4 + 2] Cycloaddition from Swertiamarin
Lu Liu1, Guan-Ling Xu1, Xiao-Xia Ma1
1Yunnan Key Laboratory of Dai and Yi Medicines, Yunnan University of Traditional Chinese Medicine , Kunming 650500, People's Republic of China.
Abstract:
Skeleton-diversity-oriented chemical conversion from pure natural products is a valuable method to obtain natural product-like compounds, especially those with novel architecture. The application of phytochemical methods to iridoids yielded three novel secoiridoid dimers: sweritranslactones A-C (1-3). These molecules possess a 6/6/6/6/6/6-fused hexacyclic skeleton and were obtained from swertiamarin, one of the major constituents of the genus Swertia, via a [4 + 2] cycloaddition and intramolecular nucleophilic addition under aqueous conditions. The structures were established based on extensive spectroscopic characterization and X-ray crystallographic diffraction analysis.
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