(1aS,3aS,6aS,6bS,7R,9aR)-7-Hydroxy-1a,7-dimethyl-4-methyleneoctahydro-1aH-oxireno[2',3':8,8a]azuleno[4,5-b]furan-5(6aH)-one is a reactant in the sysnthesis of Arglabin (A769750), a sesquiterpene lactone used in the inhibition of glucose induced NF-kB activation and MCP-1/TGF-β1 expression treating diabetic nephropathy. Cytocoxic.