2-Amino-4-(4-methoxyphenyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile 1,4-dioxane hemisolvate

In the crystal structure of the title compound, C17H16N2O3·0.5C4H8O2, pairs of N—H⋯N hydrogen bonds link molecules into dimers with R 2 2(12) motifs, which are connected by N—H⋯O hydrogen bonds, forming a supramolecular array in the ab plane. The 1,4-dioxane ring, which lies about an inversion center, adopts a chair conformation.

In the crystal structure of the title compound, C 17 H 16 N 2 O 3 Á-0.5C 4 H 8 O 2 , pairs of N-HÁ Á ÁN hydrogen bonds link molecules into dimers with R 2 2 (12) motifs, which are connected by N-HÁ Á ÁO hydrogen bonds, forming a supramolecular array in the ab plane. The 1,4-dioxane ring, which lies about an inversion center, adopts a chair conformation.
We thank Manchester Metropolitan University, the University of Sargodha and Erciyes University for guidance and for instrumental support of this study. We also extend our thanks to the Egyptian Government for their financial support of this project. Pyran and fused pyran ring systems are biologically interesting compounds known for their antimicrobial and antifungal (Alvey, et al., 2009), antioxidant (Symeonidis et al., 2009), antileishmanial (Narender et al., 2009), antitumor (Han et al., 2008). In addition, fused chromene ring systems have platelet antiaggregating, local anesthetic (Bargagna et al. 1992) and antihistaminic activities (Gorlitzer et al. 1984). They also exhibit inhibitory effects on influenza virus sialidases Taylor et al. 1998) and antiviral activities (Martinez & Marco, 1997). Such observations prompted us to report the synthesis and crystal structure of the title compound (I).
In the crystal, molecules are linked by the pairs of N-H···N hydrogen bonds, forming dimers, with an R 2 2 (12) motif (Bernstein et al., 1995;

Experimental
A mixture of (4-methoxybenzylidene)propanedinitrile (184 mg, 1 mmol), cyclohexane-1,3-dione (112 mg, 1 mmol) in presence of ethanolamine (61 mg) as catalyst was refluxed in ethanol (50 ml). The reaction mixture was monitored by TLC until completion after 7 h. A solid product was deposited on cooling at ambient temperature and collected by filtration. The crude product was washed with dioxane and recrystallized from ethanol/drops of dioxane to afford the title compound in 78% yield. Single crystals suitable for X-ray analysis were grown up on slow evaporation of its mixed solvent ethanol/dioxane (9:1) solution at room temperature over three days. M.pt: 435 K.

Computing details
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).   Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.