title: Facile synthesis of the naturally cytotoxic triterpenoid saponin Patrinia-glycoside B-II and its conformer.
abstract: The first chemical synthesis of the natural triterpenoid saponin Patrinia-glycoside B-II, namely oleanolic acid 3-O-α-L-rhamnopyranosyl-(1→2)-[β-D-gluco-pyranosyl-(1→3)]-α-L-arabinopyranoside, has been accomplished in a linear 11-step sequence 11 with 9.4% overall yield. The abnormal 1C4 conformation of the arabinose residue was found to occur via conformational fluctuation during preparation of the intermediates. Molecular mechanism and quantum chemistry calculations showed that Patrinia-glycoside B-II and its conformer 1 cannot interconvert under normal conditions. Preliminary structure-activity relationships studies indicated that the 4C1 chair conformation of the arabinose residue in the unique α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl disaccharide moiety is one of the chief positive factors responsible for its cytotoxic activity against tumors.
authors: Li
authors: L
authors: Ren
authors: Yong-Xiang
authors: YX
authors: Liu
authors: Dan
authors: D
authors: Lv
authors: Mao-Cai
authors: MC
authors: Yan
authors: Han
authors: H
authors: Nie
authors: Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China. y.liu@syphu.edu.cn.
authors: Yang
authors: Y
authors: Liu
authors: Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China. mscheng@syphu.edu.cn.
authors: Mao-Sheng
authors: MS
authors: Cheng
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D020650:Combinatorial Chemistry Techniques; D006027:Glycosides / Q000138:chemical synthesis* / Q000633:toxicity; D006801:Humans; D020128:Inhibitory Concentration 50; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009828:Oleanolic Acid / Q000737:chemistry; D032405:Patrinia / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry
chemical_list: D006027:Glycosides; D012503:Saponins; D014315:Triterpenes; D009828:Oleanolic Acid