2,2'-Dimethoxy-4,4'-[rel-(2R,3S)-2,3-di-methylbutane-1,4-diyl]diphenol.

The title mol-ecule, C(20)H(26)O(4), commonly known as meso-dihydro-guaiaretic acid, is a naturally occurring lignan extracted from Larrea tridentata and other plants. The mol-ecule has a noncrystallographic inversion center situated at the midpoint of the central C-C bond, generating the meso stereoisomer. The central C-C-C-C alkyl chain displays an all-trans conformation, allowing an almost parallel arrangement of the benzene rings, which make a dihedral angle of 5.0 (3)°. Both hydr-oxy groups form weak O-H⋯O-H chains of hydrogen bonds along [100]. The resulting supra-molecular structure is an undulating plane parallel to (010).