12-(2-Hydroxy-6-oxocyclohex-1-enyl)-9,10-dihydro-8H-benzo[a]xanthen-11(12H)-one

In the xanthenone system of the title compound, C23H20O4, the pyran ring has a maximum deviation of 0.111 (1) Å from planarity and the outer cyclohexene ring exhibits a puckered conformation. The three methylene C atoms of the cyclohexene ring bonded to the pyran unit are disordered over two sets of sites [occupancies = 0.570 (3) and 0.430 (3)]. In the crystal, molecules are linked by C—H⋯O and O—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (110). A C—H⋯π interaction occurs between these networks.

In the xanthenone system of the title compound, C 23 H 20 O 4 , the pyran ring has a maximum deviation of 0.111 (1) Å from planarity and the outer cyclohexene ring exhibits a puckered conformation. The three methylene C atoms of the cyclohexene ring bonded to the pyran unit are disordered over two sets of sites [occupancies = 0.570 (3) and 0.430 (3)]. In the crystal, molecules are linked by C-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds, forming a two-dimensional network parallel to (110). A C-HÁ Á Á interaction occurs between these networks.
Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009). AAA thanks the Ministry of Higher Education in Egypt for a grant to support this collaborative project. Manchester Metropolitan University, Erciyes University and University of Strathclyde are gratefully acknowledged for facilitating this study.

Comment
Xanthene derivatives have been used as antibacterial, antiviral, antitumor and anti-inflammatory agents (Zare et al., 2012). These compounds also have applications as dyes in laser technology (Menchen et al., 2003a,b), and as pH sensitive fluorescent materials for the visualization of biomolecules (Sarma & Baruah, 2005). Extending our previous studies of xanthenones Mohamed et al., 2011Mohamed et al., , 2012, we report herein the synthesis and crystal study of a new of xanthenone derivative.

Experimental
The title compound was obtained as the main product during a three component reaction of 1 mmol (206 mg) 4nitro-2-(trifluoromethyl)aniline, 1 mmol (172 mg) 2-hydroxy-1-naphthaldehyde and 1 mmol (112 mg) 1,3-cyclohexandione in 50 ml ethanol. The reaction mixture was refluxed for 7 h at 351 K. On cooling, the resulting solid was collected, washed with cold ethanol and dried by filtration. The crude product was crystallized by the slow evaporation method over 24 h using ethanol as a solvent. M.p. = 517 K, yield = 95%.

Refinement
The hydroxyl H atoms were found from a difference Fourier map and refined freely. The C-bound H-atoms were refined using a riding model with C-H = 0.95 -1.00 Å and U ĩso (H) = 1.2U eq (C). The three methylene C atoms (C20/C21/C22)

Figure 1
The structure of the title compound with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. For clarity only atoms of one disorder component of the disordered methylene groups are shown.   The packing and hydrogen bonding (dashed lines) of the title compound viewing along the c axis. For clarity only atoms of the major disorder component of the disordered methylene groups are shown. Hydrogen-bond geometry (Å, º) Cg3 is the centroid of the C2-C7 benzene ring.