Crystal structure of (E)-4,4'-(but-2-ene-1,4-di-yl)bis-(2-meth-oxy-phenol).

The title compound, C18H20O4, was synthesized via the ruthenium-catalyzed alkene methathesis dimerization of eugenol. The whole mol-ecule is generated by inversion symmetry; the center of inversion being located at the mid-point of the trans C=C bond. The phenol ring is inclined to the mean plane of the central C-C=C-C unit (r.m.s. deviation = 0.014†à ) by 68.83†(16)°. In the crystal, mol-ecules are linked via O-H⋯O hydrogen bonds, involving the hy-droxy and meth-oxy groups, forming undulating sheets parallel to (010).