Sesquiterpenoids from the Rhizome of Ligularia virgaurea |
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| Authors: | Xiao‐Bai Sun Yang‐Jun Xu Dong‐Feng Qiu Cheng‐Shan Yuan |
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| Institution: | 1. State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P.?R. China, (phone: +86‐0931‐891‐4178;2. fax: +86‐0931‐891‐2582) |
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| Abstract: | Two novel sesquiterpene dimers, compounds 1 and 2 , were isolated from the rhizome of Ligularia virgaurea, together with the six known sesquiterpenoids 3 – 8 . Their structures were established by physico‐chemical and spectroscopic methods, especially by means of 1D‐ and 2D‐NMR as well as HR‐MS analyses. A mechanism based on a classical Diels–Alder cyclization is proposed for the formation of the dimer 1 from the precursors 8 and the quinone form of 6 (Scheme). |
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| Keywords: | Ligularia virgaurea Sesquiterpenoids Biogenesis Diels– Alder reactions |
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