The title compound, erioflorin, C19H24O6 [systematic name: (1aR,3S,4Z,5aR,8aR,9R,10aR)-1a,2,3,5a,7,8,8a,9,10,10a-deca-hydro-3-hy-droxy-4,10a-dimethyl-8-methyl-idene-7-oxooxireno[5,6]cyclo-deca-[1,2-b]furan-9-yl methacrylate], is a tricyclic germacrane sesquiterpene lactone, which was isolated from Podanthus mitiqui (L.). The compound crystallizes in the space group P212121, and its mol-ecular structure consists of a methacrylic ester of a ten-membered ring sesquiterpenoid annelated with an epoxide and a butyrolactone. The structure is stabilized by one intramolecular C-H⋯O hydrogen bond. An O-H⋯O hydrogen bond and further C-H⋯O interactions can be observed in the packing.
Keywords: Podanthus mitiqui; crystal structure; germacrane sesquiterpene lactone.