(E)-1-(1-Hydroxynaphthalen-2-yl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one

In the title molecule, C22H20O5, the C=C bond of the central enone group adopts an E conformation. The dihedral angle formed by the benzene ring and the naphthalene ring system is 12.6 (4)°. The hydroxy group attached to the naphthalene ring is involved in an intramolecular O—H⋯O hydrogen bond. In the crystal, weak C—H⋯O hydrogen bonds link the molecules into chains along [010]. In addition, π–π stacking interactions are present, with centroid–centroid distances of 3.6648 (15) and 3.8661 (15) Å between the benzene and two naphthalene rings.

In the title molecule, C 22 H 20 O 5 , the C C bond of the central enone group adopts an E conformation. The dihedral angle formed by the benzene ring and the naphthalene ring system is 12.6 (4) . The hydroxy group attached to the naphthalene ring is involved in an intramolecular O-HÁ Á ÁO hydrogen bond. In the crystal, weak C-HÁ Á ÁO hydrogen bonds link the molecules into chains along [010]. In addition,stacking interactions are present, with centroid-centroid distances of 3.6648 (15) and 3.8661 (15) Å between the benzene and two naphthalene rings.  Jo et al. (2012). For related structures, see: Park et al. (2013); Fadzillah et al. (2012). For standard bond lengths, see: Allen et al. (1987 Table 1 Hydrogen-bond geometry (Å , ). Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).  (Hans et al. 2010). In continuation of our research interest to develop benzochalcone derivatives which show broad range of biological activities (Jo et al. 2012), titled compound was synthesized and its crystal structure was determined.

Experimental
To a solution of 2,4,5-trimethoxybenzaldehyde (196 mg, 1 mmol) in 10 ml of ethanol was added 1-hydroxy-2-acetonaphthone (186 mg, 1 mmol) and the temperature was adjusted to around 275-276 K in an ice-bath. To the cooled reaction mixture 1 ml of 50% aqueous KOH solution was added, and the reaction mixture was stirred at room temperature for 20 h. This mixture was poured into iced water (30 ml) was acidified (pH = 3) with 6 N HCl solution to give a precipitate. Filtration and washing with water afforded crude solid of the title compound (180 mg, 48%).
Recrystallization of the solid from ethanol gave yellow colored crystals (mp: 471-472 K).

Refinement
The H atoms were placed in calculated positions with C-H = 0.95 and 0.98 Å or O-H = 0.84 Å, and refined in a riding-model approximation with U iso (H) = 1.2 U eq (C) or 1.5 U eq (C methyl ) and U iso (H) = 1.5 U eq (O)].

Computing details
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.