6-Amino-3-methyl-4-(3-nitrophenyl)-1-phenyl-1H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile

The title compound, C20H15N5O3, was synthesized by the one-pot reaction of a four-component reaction protocol in aqueous medium. The pyrano[2,3-c]pyrazole system is essentially planar, with a maximum deviation of 0.026 (2) Å. The 3-nitrophenyl and phenyl rings make dihedral angles of 81.11 (5) and 13.36 (1)°, respectively, with the mean plane of the pyrano[2,3-c]pyrazole ring. The crystal structure is stabilized by N—H⋯N hydrogen bonds, which form infinite chain propagating along the c axis and by N—H⋯O hydrogen bonds, which form infinite chains propagating along the a axis. There are also N—O⋯N—C dipole–dipole interactions along the a axis with an O⋯N distance of 3.061 (3) Å, which is shorter than that of the N—H⋯O hydrogen bond [3.196 (3) Å].

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.  Multi-component reaction (MCR) protocols in water will be one of the most suitable strategies, which will meet the requirements of green chemistry as well as for developing libraries of medicinal scaffolds (Chanda et al., 2009;Tejedor et al., 2007). pyranopyrazoles are an important class of heterocyclic compounds. They found applications as pharmaceutical ingredients and biodegradable agrochemicals (Junek et al., 1973;Wamhoff et al., 1993;Sharanin et al., 1983;Vasuki et al., 2008). In order to further study the structure-activity relationship of pyranopyrazoles, we performed the synthesis of the title compound through an efficient and eco-friendly four-component one-pot reaction protocol in aqueous medium in the presence of catalytic amount dodecyltrimethylammonium bromide and present the crystal structure of the title compound in the hope that its structural features will appear interesting and helpful its practical applications. In the title molecule

Experimental
To a stirred aqueous mixture of phenylhydrazine ( 0.216g, 2 mmol) and ethyl acetoacetate ( 0.260g, 2 mmol), 3-nitrobenzaldehyde ( 0.302g, 2 mmol), malonitrile ( 0.132g, 2 mmol) and piperidine (5 mol %) were added successively at 363 K in the presence of catalytic amount dodecyltrimethylammonium bromide with vigorous stirring for 10 min. The precipitated solid was filtered, washed with water and then with a mixture of ethyl acetate/hexane (20:80). The product obtained was purified by flash chromatograghy. Single crystals of the title compound suitable for single-crystal X-ray analysis were obtained by recrystallization from ethanol.

Refinement
H atoms bonded to N atoms were located in a difference map and refined with distance restraints of N-H = 0.860 Å, and withU iso (H) =1.2U eq (N). The remaining H atoms were positioned geometrically and refined using a riding model with C-H = 0.93-0.98 Å , and with U iso (H)= 1.2U eq (C).
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title compound, with atom labels and 50% probability displacement ellipsoids for non-H atoms.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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 > 2sigma(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.