title: 4a-Hy-droxy-9-(2-meth-oxy-phen-yl)-4,4a,5,6,7,8,9,9a-octa-hydro-3H-xanthene-1,8(2H)-dione.
abstract: In the title compound, C(20)H(22)O(5), an S(6) ring motif is formed by an intra-molecular C-H⋯O hydrogen bond, which contributes to the stabilization of the mol-ecule. In the xanthene system, the cyclo-hexane ring adopts a chair conformation, the cyclo-hexene ring adopts a half-boat conformation and the tetra-hydro-pyran ring adopts a half-chair conformation. The mean plane of the four essentially planar atoms of the tetra-hydro-pyran ring [r.m.s deviation = 0.092 (1) Å] forms a dihedral angle of 64.13 (6)° with the mean plane of the meth-oxy-phenyl group. In the crystal, inter-molecular O-H⋯O and weak C-H⋯O hydrogen bonds link mol-ecules into chains along the a axis, which are further stabilized by C-H⋯π inter-actions.
authors.forename: Wan-Sin
authors.initials: WS
authors.lastname: Loh
authors.forename: Hoong-Kun
authors.initials: HK
authors.lastname: Fun
authors.forename: B Palakshi
authors.initials: BP
authors.lastname: Reddy
authors.forename: V
authors.initials: V
authors.lastname: Vijayakumar
authors.forename: S
authors.initials: S
authors.lastname: Sarveswari