2-Ethoxy-4-(4-methylphenyl)-6-phenylpyridine-3-carbonitrile

The title compound, C21H18N2O, crystallized with two independent molecules (A and B) in the asymmetric unit. In molecule A, the central pyridine ring forms dihedral angles of 14.55 (13) and 39.14 (12)° with the terminal phenyl and benzene rings, respectively. The latter rings make a dihedral angle of 33.06 (13)° with each other. The corresponding values for molecule B are 26.86 (13), 41.82 (12) and 38.99 (13)°, respectively. In the crystal, the B molecules are linked via a pair of weak C—H⋯N hydrogen bonds, forming inversion dimers. In addition, C—H⋯π interactions and π–π [centroid–centroid distances = 3.5056 (16) and 3.8569 (17) Å] stacking interactions are observed.

The title compound, C 21 H 18 N 2 O, crystallized with two independent molecules (A and B) in the asymmetric unit. In molecule A, the central pyridine ring forms dihedral angles of 14.55 (13) and 39.14 (12) with the terminal phenyl and benzene rings, respectively. The latter rings make a dihedral angle of 33.06 (13) with each other. The corresponding values for molecule B are 26.86 (13), 41.82 (12) and 38.99 (13) , respectively. In the crystal, the B molecules are linked via a pair of weak C-HÁ Á ÁN hydrogen bonds, forming inversion dimers. In addition, C-HÁ Á Á interactions and -[centroidcentroid distances = 3.5056 (16) and 3.8569 (17) Å ] stacking interactions are observed.  Table 1 Hydrogen-bond geometry (Å , ).

El-Remaily Comment
Pyridine containing compounds possess a wide range of biological properties (Cook et al., 2004;Upton et al., 2000;Ellefson et al., 1978). Functionalized pyridine derivatives can act as antifungal (Cook et al., 2004), antifertility (Upton et al., 2000 and antiarrhythmic agents (Ellefson et al., 1978). We herein report on the synthesis and crystal structure of the title compound as a part of our on-going project on the synthesis of bioactive molecules (El-Sawy et al., 2012;Soliman et al., 2012).
The solid product that resulted on cooling was filtered off, dried and recrystallized from acetone. Single crystals suitable for X-ray analyses were grown by slow evaporation of an acetone solution of the title compound over 24 h [M.p. 383 K].

Refinement
All H atoms were positioned geometrically with C-H = 0.93 Å (aromatic), 0.97 Å (methylene) and 0.96 Å (methyl). The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms.

Figure 1
The molecular structure of molecule A in the asymmetric unit of the title compound, with the atom numbering. Displacement ellipsoids are drawn at the 50% probability level.  The molecular structure of molecule B in the asymmetric unit of the title compound, with the atom numbering.
Displacement ellipsoids are drawn at the 50% probability level.

2-Ethoxy-4-(4-methylphenyl)-6-phenylpyridine-3-carbonitrile
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.