| 1 | Rhodauricanol A, an analgesic diterpenoid with an unprecedented5/6/5/7 tetracyclic system featuring a unique16-oxa-tetracyclo[11.2.1.0^(1,5).0^(7,13)]hexadecane core from Rhododendron dauricum显示文摘A novel diterpenoid with an unprecedented 5/6/5/7 tetracyclic system, rhodauricanol A(1), five new grayanane-derived diterpenoids, dauricanols A-E(2-6), and five known ones(7-11) were isolated from the flowers of Rhododendron dauricum. Rhodauricanol A(1) possesses a unique 5/6/5/7 tetracyclic ring system featuring a 16-oxa-tetracyclo[11.2.1.0^(1,5).0^(7,13)]hexadecane core. Dauricanols A-C(2-4) are the first1,3-dioxolane conjugates of grayanane diterpenoids and 5-hydroxymethylfurfural and vanillin, respectively, and dauricanols D(5) and E(6) represent the first examples of 6-deoxy-1,5-seco-grayanane diterpenoids. Their structures were determined by spectroscopic methods, quantum chemical calculation including ^(13)C NMR-DP4+ analysis and ECD calculation, and single-crystal X-ray diffraction analysis. Plausible biosynthetic pathways for 1-4 were proposed. All the isolates showed significant analgesic activities,and dauricanols B(3) and C(4) showed more potent analgesic activities than the positive control, morphine. | Yuanyuan Feng Suqin Zha Hanqi Zhang Biao Gao Guijuan Zheng Pengfei Jin Yingyi Chen Guangmin Yao | 2023 | Chinese Chemical Letters2023，34，4： | 1 |
| 2 | Discovery of Kalmane Diterpenoids as Potent Analgesics from the Flowers of Rhododendron dauricum显示文摘Kalmane diterpenoids,featuring a 5/8/5/5 tetracyclic carbon skeleton,are very rare in nature.The flowers of Rhododendron dauricum L.(Ericaceae)were phytochemically investigated for the first time,leading to the isolation of eight kalmane diterpenoids(1-8)including four new ones,named rhodokalmanols A-D(1-4).The structures of 1-8 were elucidated by comprehensive spectroscopic methods and ic NMR-DP4+analysis,and the absolute configurations of 1,2,4,and 5 were defined by single-crystal X-ray diffraction analysis with Cu Kαradiation.Rhodokalmanol A(1)represents the first 5,8-epoxykalmane diterpenoid and also the first kalm-15(16)-ene diterpenoid.Rhodokalmanols BD(2-4)are the first examples of kalm-7(8)-ene,kalm-16(17)-ene,and 8α-methoxykalmane diterpenoids,respectively.All the isolated kalmane diterpenoids 1-8 exhibited significant analgesic effects,and rhodokalmanol C(3)and kalmanoi(8)expressed more potent analgesic activity than morphine at doses of 0.2 and 0.04 mg/kg.The preliminary structure-activity relationships of kalmane diterpenoids as potent analgesics are discussed. | Yuanyuan Feng Suqin Zha Biao Gao Hanqi Zhang Pengfei Jin Guijuan Zheng Yilin Ma Guangmin Yao | 2022 | Chinese Journal of Chemistry2022，40，9： | 1 |
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