2,6-Diamino-4-(4-chlorophenyl)-1-methyl-1,4-dihydropyridine-3,5-dicarbonitrile

In the title compound, C14H12ClN5, the dihydropyridine ring adopts a shallow boat conformation. The dihedral angle between the plane of this ring and that of the chlorobenzene ring is 69.15 (15)°. In the crystal, molecules are linked by N—H⋯N and N—H⋯Cl hydrogen bonds, generating (001) sheets.

In the title compound, C 14 H 12 ClN 5 , the dihydropyridine ring adopts a shallow boat conformation. The dihedral angle between the plane of this ring and that of the chlorobenzene ring is 69.15 (15) . In the crystal, molecules are linked by N-HÁ Á ÁN and N-HÁ Á ÁCl hydrogen bonds, generating (001) sheets.

Related literature
For background to malononitrile, see: Fatiadi (1978); Raghukumar et al. (2003). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 Table 1 Hydrogen-bond geometry (Å , ). Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009). Malononitrile is a simple and versatile reagent for the synthesis of heterocyclic compounds and precursors of novel compounds. It exhibits a unique reactivity due to the strong electron withdrawing cycano groups to activate the methylene group and the polar multiple bond suitable for nucleophilic addition (Fatiadi, 1978). Malononitrile is used as reactant or reaction intermediate in various multicomponent reactions to prepare heterocyclic compounds. The three component reactions of malononitrile, aldehyde and amine show very chemical diversity, from which several kinds of products were separated (Raghukumar et al., 2003). The crystal structure of the title compound (I) is presented here.
The crystal structure shown in Fig. 2 features N2-H1N2···N5 i and N3-H2N3···N4 iii hydrogen bonds (symmetry code in Table 1) to result in tetrameric association of molecules, generated by inversion. These tetramers are then connected via N2-H2N2···Cl1 ii hydrogen bond (symmetry code in Table 1), forming a layer parallel to the ab plane.

Experimental
Compound (I) was prepared by the reaction of p-chlorobenzaldehyde (1 mmol), malononitrile (1 mmol) and methylamine (1 mmol) in a mixed solvent of methanol and water (5:1) was stirred at room temperature about an hour. The resulting precipitate was collected by filtration and washed with methanol to afford pure product, m.p: 290 °C. The product was crystallized from methanol solution as colourless plates.

Refinement
N-bound H atoms were located in a difference Fourier maps and allowed to be refined freely [refined distance: N-H = 0.83 (4)-0.89 (4) Å]. The remaining hydrogen atoms were positioned geometrically [C-H= 0.95 or 0.98 Å] and were refined using a riding model, with U iso (H) = 1.2 U eq (C) or 1.5 U eq (methyl C). A rotating-group model was used for the methyl group.  The molecular structure of the title compound with 50% probability displacement ellipsoids.  The crystal packing of the title compound. The H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.  (Cosier & Glazer, 1986) operating at 100.0 (1) K. Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 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.