(3R*,6S*,6aR*,9S*,9aS*)-6,6a,9-Trihydroxy-3,6,9a-trimethyl­perhydro­azuleno[1,2-b]furan-2-one

The title compound, C₁₅H₂₄O₅, was isolated from the flowers of Parthenium hysterophorus. The crystal structure determination confirms the relative stereochemistry unambiguously. The packing is stabilized by O—H...O hydrogen bonding.

A clerodane diterpenoid from Pulicaria wightiana

The structure of the clerodane diterpene C₂₁H₃₀O₅, with modest antibacterial activity and isolated from the plant Pulicaria wightiana, was established to be meth­yl 6α-hydr­oxy-3,13-clerodadien-15,16-olid-18-oate. The fused six-membered rings of the deca­lin system have sofa and chair conformations. The furan­one side chain is in an antiperiplanar conformation. The mol­ecules in the crystal structure are stabilized by an intra­molecular O—H...O hydrogen bond and a chain of inter­molecular C—H...O inter­actions.