title: Methyl 2-(1a,4a-dimethyl-2,8-dioxo-2,3,4,4a,5,6,7,8-octa-hydro-1aH-1-oxacyclo-propa[d]naphthalen-7-yl)acrylate.
abstract: The title compound, C(16)H(20)O(5), was synthesized from ilicic acid [2-(8-hy-droxy-4a,8-dimethyl-deca-hydro-naphthalen-2-yl)acrylic acid], which was isolated from the chloro-form extract of the aerial part of Inula viscose (L) Aiton [or Dittrichia viscosa- (L) Greuter]. The molecule is built up from two fused six-membered rings, the epoxidized six-membered ring adopts a half-chair conformation while the other ring displays a perfect chair conformation. The crystal structure features C-H⋯O hydrogen bonds.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Tebbaa
authors.forename: Ahmed
authors.initials: A
authors.lastname: Benharref
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Daran
authors.forename: Fouad
authors.initials: F
authors.lastname: Mellouki
authors.forename: Moha
authors.initials: M
authors.lastname: Berraho