Diethyl 2,6-dimethyl-4-(5-phenyl-1H-pyrazol-4-yl)-1,4-dihydropyridine-3,5-dicarboxylate

In the title compound, C22H25N3O4, the dihydropyridine ring adopts a flattened boat conformation. The pyrazole ring makes a dihedral angle of 29.04 (5)° with the benzene ring. The molecular structure is stabilized by an intramolecular C—H⋯O hydrogen bond which generates an S(9) ring motif. In the crystal, molecules are linked via N—H⋯O and C—H⋯N hydrogen bonds into a two-dimensional network parallel to the ab plane. The crystal structure is further consolidated by weak C—H⋯π interactions.

In the title compound, C 22 H 25 N 3 O 4 , the dihydropyridine ring adopts a flattened boat conformation. The pyrazole ring makes a dihedral angle of 29.04 (5) with the benzene ring. The molecular structure is stabilized by an intramolecular C-HÁ Á ÁO hydrogen bond which generates an S(9) ring motif. In the crystal, molecules are linked via N-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonds into a two-dimensional network parallel to the ab plane. The crystal structure is further consolidated by weak C-HÁ Á Á interactions.
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 (Stout & Meyers, 1982) scaffold is a heterocyclic unit with remarkable pharmacological efficiency. They are widely used clinically as calcium channel blockers for the treatment of cardiovascular diseases. For example, nifedipine and nitrendipine are used for the treatment of hypertension and angina pectorism with nisoldipine being a potent vasodilator and nimodipine exhibiting selectivity for cerebral vasculature (Böcker & Guengerich, 1986). A number of DHP derivatives are employed as potential drug candidates for the treatment of congestive heart failure (Vo et al., 1995). Prompted by the diverse activities of 1,4-dihydropyridines, we have synthesized the title compound to study its crystal structure.

Refinement
Atoms H1 and H2 were located in a difference map and were fixed at their found positions with U iso (H) = 1.2 U eq (N) (N -H = 0.8870 and 0.9024 Å). The remaining H atoms were positioned geometrically and refined using a riding model, with U iso (H) = 1.2 or 1.5U eq (C) (C-H = 0.93-0.98 Å). A rotating group model was applied to the methyl groups. In the final refinement, the outliners (1 3 3), (-2 3 0) and (-2 3 10) were omitted.

Figure 1
The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme. Intramolecular hydrogen bond was shown as dash line.

Figure 2
The crystal packing of the title compound, viewed along the b axis. 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.