The structure of echinothiophene, the β-D-glucoside of a benzo[b]thiophene lactone bearing a novel skeleton, has been deduced from extensive NMR and MS studies. The compound undergoes facile epimerization at the C-6 center, perhaps through the enol 2. Molecular mechanics and dynamics calculations indicated that the structure 1 (C-6, R) is more stable than 3 (C-6, S).
Echinops grijissii, benzothiophene glycoside, echinothiophene
Publication DOI: 10.1021/ol9905295Journal NLM ID: 100890393Publisher: American Chemical Society
Correspondence: Nikaido T
Institutions: School of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan, School of Pharmaceutical Sciences, Beijing Medical University, Beijing 100083, China
Methods: 13C NMR, 1H NMR, IR, HPLC, UV, molecular modeling, molecular mechanics, RP-HPLC, HMBC, DEPT, COSY, NOESY, HOHAHA, HSQC, HR-FAB-MS, molecular dynamics
Found