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NMR and x‐ray conformational study of artemisiifolin and three other related germacranolides
Author(s) -
Jimeno María L.,
ApredaRojas María del Carmen,
Cano Félix H.,
Rodríguez Benjamín
Publication year - 2004
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1352
Subject(s) - chemistry , germacranolide , acetone , ring (chemistry) , crystallography , stereochemistry , diffraction , quantum chemical , cyclohexane conformation , x ray crystallography , nuclear magnetic resonance spectroscopy , lactone , molecule , organic chemistry , hydrogen bond , physics , optics
From an acetone extract of Staehelina dubia , large quantities of the previously known germacranolide artemisiifolin were isolated. The conformations of the 10‐membered germacra‐1(10) E ,4 Z ‐diene ring system of this compound and those of its derivatives 11,13‐dihydroartemisiifolin, isabelin and 6α‐hydroxy‐15‐oxogermacra‐1(10) E ,4 Z ,11(13)‐trien‐12,8α‐olide were studied by NMR spectroscopic methods. Low‐energy conformations were obtained by quantum mechanical calculations. An x‐ray diffraction analysis of artemisiifolin established that, in the crystalline state, it possesses a unique conformation that corresponds to the majority one existing in acetone‐ d 6 solution. Copyright © 2004 John Wiley & Sons, Ltd.