Crystal structure and conformational analysis of 2-hy-droxy-3-(2-methyl-prop-1-en-1-yl)naphthalene-1,4-dione.

In the structure of the title compound, C14H12O3, the substituent side chain, in which the H atoms of both methyl groups are disordered over six equivalent sites, lies outside of the plane of the naphthalene-dione ring. The ring-to-chain C-C-C-C torsion angles are 50.7 (3), -176.6 (2) and 4.9 (4)°. An intra-molecular meth-yl-hy-droxy C-H⋯O hydrogen bond is present. In the crystal, mol-ecules are primarily connected by inter-molecular O-H⋯O hydrogen bonds, forming a centrosymmetric cyclic dimer motif [graph set R 2 (2)(10)]. Also present is a weak inter-molecular C-H⋯O hydrogen bond linking the dimers and a weak π-π ring inter-action [ring centroid separation = 3.7862 (13) Å], giving layers parallel to (10-3).