9-(4-Methoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7-tetrahydro-2H-xanthene-1,8(5H,9H)-dione

In the molecule of the title compound, C24H28O4, the three six-membered rings of the xanthene system are not planar, having envelope, boat and envelope conformations. In the crystal structure, C—H⋯O hydrogen bonds link the molecules, generating centrosymmetric R 2 2(12), R 4 4(28) and R 2 2(16) ring motifs and forming a three-dimensional network.

In the molecule of the title compound, C 24 H 28 O 4 , the three sixmembered rings of the xanthene system are not planar, having envelope, boat and envelope conformations. In the crystal structure, C-HÁ Á ÁO hydrogen bonds link the molecules, generating centrosymmetric R 2 2 (12), R 4 4 (28) and R 2 2 (16) ring motifs and forming a three-dimensional network.
In the crystal structure, intermolecular C-H···O hydrogen bonds (Table 1) (Bernstein et al., 1995;Etter, 1990), to form a three-dimensional network, in which they may be effective in the stabilization of the structure.

Refinement
H atoms were positioned geometrically, with C-H = 0.93, 0.96, 0.97 and 0.98 Å for aromatic, methyl, methylene and methine H, respectively, and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C).
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
. H atoms not involved in hydrogen bondings have been omitted for clarity.