2-(Morpholin-4-yl)-6-(1H-pyrrol-1-yl)pyridine-3,5-dicarbonitrile

In the title compound, C15H13N5O, the morpholine ring adopts a chair conformation. The dihedral angle between the pyrrole ring and the pyridine ring is 28.93 (14)°. In the crystal, the molecules are linked by C—H⋯O hydrogen bonds occur, and aromatic weak π–π stacking [centroid–centroid separation = 4.178 (2) Å] and C—H⋯π interactions consolidate the packing.

In the title compound, C 15 H 13 N 5 O, the morpholine ring adopts a chair conformation. The dihedral angle between the pyrrole ring and the pyridine ring is 28.93 (14) . In the crystal, the molecules are linked by C-HÁ Á ÁO hydrogen bonds occur, and aromatic weakstacking [centroid-centroid separation = 4.178 (2) Å ] and C-HÁ Á Á interactions consolidate the packing.
The EPSRC National Crystallography Service is gratefully acknowledged for X-ray diffractions. The authors are thankful to Manchester Metropolitan University and Sohag University for supporting this study.  The pyridine skeleton is of great importance to chemists as well as to biologists as it is found in a large variety of naturally occurring compounds and also in clinically useful molecules having diverse biological activities. Its derivatives are known to possess antitubercular (Mikail et al., 2001), anti-ulcer (Cho et al., 2001), antimicrobial (Yeong et al., 2004Goda et al., 2004), antitumor (Tiwari et al., 2002Kovala-Demertzi et al., 2007), antiviral (Sylvie et al., 2002) and cardio tonic properties (Altomare et al., 2000). Poly-substituted pyridines, especially the 3,5-pyridinedicarbonitriles, are interesting as antioxidants and NADH co-enzyme analogues that mediate hydrogen transfer in biological systems, and for their antihistaminic, anti-inflammatory and analgesic activity (Hosni & Abdualla, 2008). In addition, it was found that drugs containing morpholine moiety in their structures have exhibited remarkable biological properties (Basavaraja et al., 2010). These facts stimulated us to synthesis the title compound for its potential biological activity. The crystal structure is stabilized by intermolecular C-H···O hydrogen bonds (Table 1, Fig. 2) and weak π-π stacking [Cg1···Cg3(1 -x, -y, 1 -z) = 4.178 (2) Å; where Cg1 and Cg3 are the centroids of the N2/C8-C11 pyrrole and N1/C1-C5 pyridine rings, respectively] and C-H···π interactions.

Experimental
An equimolar mixture of 2-amino-6-morpholin-4-ylpyridine-3,5-dicarbonitrile and 2,5-dimethoxytetrahydrofuran was refluxed in acetic acid at 491 K for one hour. The solid was obtained on cooling, filtered, washed with water and recrystallized from ethanol to afford the title compound. 89% yield, m.p. 433 K. Needle crystals of the title compound, suitable for X-ray diffraction, were obtained by slow evaporation of a solution in ethanol over 24 h.

Refinement
All H-atoms were placed in calculated positions [C-H = 0.93 Å for aromatic and C-H = 0.97 Å for methylene U iso (H) = 1.2 U eq (C)] and were refined using a riding model approximation. The (-3 -2 1) and (-4 -3 1) reflections were omitted owing to bad disagreement.

Figure 1
The molecular structure of (I), showing the atom-numbering scheme and displacement ellipsoids drawn at the 50% probability level. View of the packing and hydrogen bonding of (I) down the b axis. The hydrogen atoms not involved in the hydrogen bonds have been omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.35 e Å −3 Δρ min = −0.39 e Å −3

Special details
Experimental. Rigaku CrystalClear-SM Expert 2.0 r10 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.