4,4 #8242;-[(2R,3R,4R,5R)-3,4-Dimethyltetrahydrofuran-2,5-diyl]diphenol

The title molecule, C18H20O3, is a furanoid lignan extracted from the leaves of Larrea tridentata. The relative absolute configuration for the four chiral centers was established, showing that this compound is 4-epi-larreatricin, which has been previously reported in the literature. The molecule displays noncrystallographic C2 symmetry, with the methyl and phenol substituents alternating above and below the mean plane of the furan ring. The conformation of this ring is described by the pseudorotation phase angle P = 171.3° and the maximum out-of-plane pucker νm = 37.7°. These parameters indicate that the furan ring adopts the same conformation as the ribose residues in B-DNA. The packing is dominated by intermolecular O—H...O hydrogen bonds. The phenol hydroxy groups form chains in the [110] direction and these chains interact via O—H...O(furan) contacts.