NMR and x-ray conformational study of artemisiifolin and three other related germacranolides.
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.
Jimeno
María L
ML
Centro de Química Orgánica Manuel Lora-Tamayo, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain. iqolj13@iqog.csic.es
del Carmen Apreda-Rojas
María
M
Cano
Félix H
FH
Rodríguez
Benjamín
B
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*
D005663:Furans; D010936:Plant Extracts; C017879:germacanolide; C011471:folin