title: Arctigenin: a lignan from Arctium lappa.
abstract: The title compound {systematic name: (3R-trans)-4-[(3,4-dimethoxy-phen-yl)meth-yl]-3-[(4-hydr-oxy-3-methoxy-phen-yl)meth-yl]-4,5-dihydrofuran-2(3H)-one}, C(21)H(24)O(6), has a dibenz-yl-butyrolactone skeleton. The two aromatic rings are inclined at a dihedral angle of 68.75 (7)° with respect to each other. The lactone ring adopts an envelope conformation. A series of O-H⋯O and C-H⋯O hydrogen bonds contribute to the stabilization of the crystal packing. The absolute configuration was assigned on the basis of the published literature.
authors.affiliation: School of Food Science, Henan Institute of Science and Technology, Xinxiang 453003, People's Republic of China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Gao
authors.forename: Guanglei
authors.initials: G
authors.lastname: Li
authors.forename: Junhe
authors.initials: J
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng