8?-Eth-oxy-eremophil-3,7(11)-diene-8?,12;6?,15-diolide.

ABSTRACT: The title compound, C17H20O5, an eremophilane sesquiternoid, was isolated from the roots of Ligularia lapathifolia. The mol-ecule 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 eth-oxy groups adopt a syn conformation and the A/B ring junction is cis-fused. No directional inter-molecular inter-actions could be identified in the crystal.

SUBMITTER: Fei DQ 

PROVIDER: S-EPMC3770365 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature