9-[(E)-2-(2-Methoxyphenyl)ethenyl]-3,4,5,6,7,9-hexahydro-2H-xanthene-1,8-dione

In the title compound, C22H22O4, the two cyclohexenone rings adopt half-chair conformations, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating from the plane of the other four atoms by 0.142 (2) and 0.287 (2)Å, respectively. In the crystal, weak C—H⋯O hydrogen bonds link molecules into chains running parallel to the a axis.

In the title compound, C 22 H 22 O 4 , the two cyclohexenone rings adopt half-chair conformations, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating from the plane of the other four atoms by 0.142 (2) and 0.287 (2)Å , respectively. In the crystal, weak C-HÁ Á ÁO hydrogen bonds link molecules into chains running parallel to the a axis. H atoms treated by a mixture of independent and constrained refinement Á max = 0.25 e Å À3 Á min = À0.21 e Å À3 Table 1 Hydrogen-bond geometry (Å , ). Data collection: RAPID-AUTO (Rigaku, 2006); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku, 2010); software used to prepare material for publication: CrystalStructure.

Related literature
Fiancial support from the Korea Institute of Science and Technology (KIST) is gratefully acknowledged.
In C 22 H 22 O 4 , (Fig. 1), the bond lengths and angles are normal and correspond to those observed in related structures (Asad et al., 2012;Fun et al., 2011;Mehdi et al., 2011). The methoxyphenyl group in molecule is almost planar [C26-O4-C25-C26 = -174.54 (16)°]. The two cyclohexenone rings in display half-chair conformation, Fig. 1. Atom C4 lies 0.621 (2)Å above the plane of the remaining 5 atoms of the ring containing atoms C1 to C6. Atom C9 lies 0.621 (2)Å above the plane of the remaining 5 atoms of the ring containing atoms C7 to C12. In the six-membered xanthene ring adopts a flattened boat conformation with the O1 and methine, 13, atoms deviating from the plane of the other four atoms by 0.142 (2)Å and 0.287 (2) Å.
In the crystal, a weak intermolecular C-H···O hydrogen bonds (Table 1) links the molecules into chains which run parallel to the a-axis.

Refinement
Atoms H18 and H19 were located from a difference   Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . Rfactor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).