5,6-Dimethyl-1,2,9,10-tetra-hydro-pyrano[3,2-f]chromene-3,8-dione.
The title mol-ecule, C(14)H(14)O(4), lies on a twofold rotation axis that bis-ects the central benzene ring, with only one half-mol-ecule in the asymmetric unit. The pyran-one systems adopt distorted twist- boat conformations, with the two methyl-ene C atoms displaced by 0.537 (1) and 0.163 (2) Å from the best-fit plane through the remaining five C and O atoms (r.m.s. deviation = 0.073 Å). In the crystal, bifurcated C-H⋯(O,O) hydrogen bonds link pairs of adjacent mol-ecules in an obverse fashion, stacking mol-ecules along c. These contacts are further stabilized by very weak π-π inter-actions between adjacent benzene rings with centroid-centroid distances of 4.1951 (4) Å. Additional C-H⋯O contacts link these stacks, giving a three-dimensional network.
Department of Chemistry, University of Otago, PO Box 56, Dunedin,  New Zealand.
Shailesh K
SK
Goswami
Lyall R
LR
Hanton
C John
CJ
McAdam
Stephen C
SC
Moratti
Jim
J
Simpson