title: An Approach for Determining the Absolute Configuration of C-2 in 2-Oxygenated Phenylethanoid Glycosides by (1)H NMR Spectroscopy.
abstract: The absolute configurations of 2-oxygenated phenylethanoid glycosides were conveniently determined by (1)H NMR spectroscopy. A comparison of the chemical shift differences (Δδ) of the diastereotopic methylene protons (H-1) demonstrate that a large chemical shift difference corresponds to an R configuration and a small chemical shift difference indicates S for the 2-alkoxy form. However, the situation is contrary to that of the 2-hydroxy form. Furthermore, the mechanism underlying this result is discussed based on the visualized conformations of such compounds.
authors.affiliation: 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, People's Republic of China.
authors.forename: Si-Yuan
authors.initials: SY
authors.lastname: Shao
authors.affiliation: 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, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: 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, People's Republic of China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Yang
authors.affiliation: 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, People's Republic of China.
authors.forename: Zi-Ming
authors.initials: ZM
authors.lastname: Feng
authors.affiliation: 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, People's Republic of China.
authors.forename: Jian-Shuang
authors.initials: JS
authors.lastname: Jiang
authors.affiliation: 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, People's Republic of China.
authors.forename: Pei-Cheng
authors.initials: PC
authors.lastname: Zhang