Melampodinone

The title compound, methyl {1aS-[1aR*,2aR*,3aR*,4E,5aS*,8aR*,9R*(2S*,3S*),9aR*]}-9-{[(2,3-di­methyl­oxiranyl)­carbon­yl]­oxy}-2a,3a,5a,7,8,8a,9,9a-octa­hydro-4-methyl-8-methyl­ene-2,7-dioxobisoxireno­[4,5:7,8]­cyclo­deca­[1,2-b]­furan-1a(2H)-carboxyl­ate, C₂₁H₂₂O₁₀, is an oxidation product of melampodin A. It has Z′ = 2, and the conformations of the ten-membered rings in the two mol­ecules are quite similar, with a mean difference of 2.4° between endocyclic torsion angles.