8β-Ethoxyeremophil-3,7(11)-diene-8α,12;6α,15-diolide

• Main Authors: Dong-Qing Fei, Le-Le Dong, Hui-Hong Li, Zhan-Xin Zhang
• Format: Article
• Language: English
• Published: International Union of Crystallography 2013-07-01
• Series: Acta Crystallographica Section E
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S1600536813015729

The title compound, C17H20O5, an eremophilane sesquiternoid, was isolated from the roots of Ligularia lapathifolia. The molecule contains four fused rings of which the six-membered ring A adopts a half-chair conformation, the six-membered ring B adopts a chair conformation, the five-membered ring C is almost planar (r.m.s. deviation = 0.015 Å) and the five-membered ring D adopts an envelope conformation with the quaternary C atom as the flap. The methyl and the ethoxy groups adopt a syn conformation and the A/B ring junction is cis-fused. No directional intermolecular interactions could be identified in the crystal.