N-Substituted acetamide glycosides from the stems of Ephedra sinica |
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| Institution: | 1. State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China;2. Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China;1. Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China;2. School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Nature Products, Kunming Medical University, Kunming 650500, PR China;1. Department of Pharmacognosy, Isfahan University of Medical Sciences, Hezar Jerib Avenue, 73461 Isfahan, Iran;2. Dipartimento di Agraria, Università di Napoli Federico II, Via Università 100, 80055 Portici, Naples, Italy;1. College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, China;2. State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;1. Ministry of Education, School of Chemical Science and Technology, Yunnan University, Kunming 650091, Yunnan, PR China;2. State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, University of Chinese Academy of Sciences, Kunming 650201, Yunnan, PR China;1. Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, Saskatchewan, Canada S7N 0X2;2. National Research Council Canada, Saskatoon, Saskatchewan, Canada S7N 0W9 |
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| Abstract: | Five new N-mono-/bis-substituted acetamide glycosides, N-{4-O-3-O-(4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (1), N-methyl-N-{4-O-3-O-(4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (2), N-methyl-N-{4-O-3-O-(6-O-benzoyl-4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (3), N-methyl-N-{4-O-3-O-(6-O-benzoyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (4), and N-methyl-N-{4-O-3-O-(6-O-trans-cinnamoyl-4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (5), along with one known acetamide derivative, N-methyl-N-(4-hydroxyphenethyl)-acetamide, the shared aglycone of 2–5, were isolated from the ethanol extract of the stems of Ephedra sinica. The structures of these new compounds were elucidated on the basis of extensive spectroscopic examination, mainly including multiple 1D and 2D NMR and HRESIMS examinations, and qualitative chemical tests. All N,N-bissubstituted acetamide glycosides were found to show the obvious rotamerism, as in the case of the isolated known N-methyl-N-(4-hydroxyphenethyl)-acetamide, under the experimental NMR conditions, with the ratios of integrated intensities between anti- and syn-rotamers always being found to be about 4 to 3. |
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| Keywords: | Ephedraceae Rotamerism |
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