title: NMR and x-ray conformational study of artemisiifolin and three other related germacranolides.
abstract: 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,4Z-diene ring system of this compound and those of its derivatives 11,13-dihydroartemisiifolin, isabelin and 6alpha-hydroxy-15-oxogermacra-1(10)E,4Z,11(13)-trien-12,8alpha-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-d6 solution.
authors.affiliation: Centro de Química Orgánica Manuel Lora-Tamayo, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain. iqolj13@iqog.csic.es
authors.forename: María L
authors.initials: ML
authors.lastname: Jimeno
authors.forename: María
authors.initials: M
authors.lastname: del Carmen Apreda-Rojas
authors.forename: Félix H
authors.initials: FH
authors.lastname: Cano
authors.forename: Benjamín
authors.initials: B
authors.lastname: Rodríguez
mesh_terms: D000465:Algorithms; D005663:Furans / Q000032:analysis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D008968:Molecular Conformation; D010936:Plant Extracts / Q000032:analysis* / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D005663:Furans; D010936:Plant Extracts; C017879:germacanolide; C011471:folin