title: (E)-9-(4-Chloro-styr-yl)-3,4,5,6,7,9-hexa-hydro-2H-xanthene-1,8-dione.
abstract: In the title compound, C(21)H(19)ClO(3), the two cyclo-hexenone rings adopt half-chair conformations, whereas the pyran ring adopts a boat conformation. The 4-chloro-phenyl ring is almost perpendicular to the plane through the four C atoms of the pyran ring [dihedral angle = 87.97 (6)°]. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into a chain parallel to the a-axis.
authors.forename: Jae Kyun
authors.initials: JK
authors.lastname: Lee
authors.forename: Ae Nim
authors.initials: AN
authors.lastname: Pae
authors.forename: Yong Seo
authors.initials: YS
authors.lastname: Cho
authors.forename: Joo Hwan
authors.initials: JH
authors.lastname: Cha