Crystal structure of erioflorin isolated from (L.).

The title compound, erioflorin, CHO [systematic name: (1a,3,4,5a,8a,9,10a)-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-]furan-9-yl methacrylate], is a tricyclic germacrane sesquiterpene lactone, which was isolated from (L.). The compound crystallizes in the space group 222, 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.