Crystal structure of (E)-3-(3,4-di-meth-oxy-phen-yl)-1-(1-hy-droxy-naphthalen-2-yl)prop-2-en-1-one.

The mol-ecular structure of the title compound, C21H18O4, consists of a 3,4-di-meth-oxy-phenyl ring and a naphthalene ring system linked via a prop-2-en-1-one spacer. The mol-ecule is almost planar, with a dihedral angle between the benzene ring and the naphthalene ring system of 2.68 (12)°. There is an intra-molecular O-H⋯O hydrogen bond involving the adjacent hy-droxy and carbonyl groups. The mol-ecule has an E conformation about the C=C bond and the carbonyl group is syn with respect to the C=C bond. In the crystal, mol-ecules are linked by bifurcated C-H⋯(O,O) hydrogen bonds, enclosing an R 2 (1)(6) ring motif, and by a further C-H⋯O hydrogen bond, forming undulating sheets extending in b- and c-axis directions. There are π-π inter-actions between the sheets, involving inversion-related naphthalene and benzene rings [inter-centroid distance = 3.7452 (17) Å], forming a three-dimensional structure.