(2E)-3-(2-Chloro-8-methylquinolin-3-yl)-1-(2,4-dimethylquinolin-3-yl)prop-2-en-1-one

In the molecule of the title compound, C24H19ClN2O, the terminal quinolinyl residues are close to perpendicular to each other [dihedral angle 83.72 (4)°]. The quinolinyl residues are connected by and inclined to the prop-2-en-1-one bridge, with the Car—Car—C—C (ar = aromatic) torsion angles being 71.01 (17) and 20.6 (2)°. The crystal structure features phenyl–carbonyl C—H⋯O interactions and π–π interactions between centrosymmetrically related quinolinyl residues [3.5341 (10) and 3.8719 (9) Å], which together lead to a three-dimensional architecture.

In the molecule of the title compound, C 24 H 19 ClN 2 O, the terminal quinolinyl residues are close to perpendicular to each other [dihedral angle 83.72 (4) ]. The quinolinyl residues are connected by and inclined to the prop-2-en-1-one bridge, with the C ar -C ar -C-C (ar = aromatic) torsion angles being 71.01 (17) and 20.6 (2) . The crystal structure features phenylcarbonyl C-HÁ Á ÁO interactions andinteractions between centrosymmetrically related quinolinyl residues [3.5341 (10) and 3.8719 (9) Å ], which together lead to a three-dimensional architecture.
Finally, when the structures are viewed normal to the ethylene bond, the pyridyl-N atoms in (I) can be described as anti, whereas they are closer to syn in (II).
Then the reaction mixture was neutralized with dilute acetic acid and the resultant solid was filtered, dried and purified by column chromatography using ethyl acetate-hexane (1:1) mixture to afford (I). Re-crystallization was by slow evaporation of an acetone solution of (I), which yielded pale-yellow blocks in 78% yield; m.p. 458-460 K.

Refinement
Carbon-bound H atoms were placed in calculated positions [C-H = 0.95-0.98 Å, U iso (H) = 1.2-1.5U eq (C)] and were included in the refinement in the riding-model approximation.

Figure 1
The molecular structure of (I), showing displacement ellipsoids at the 50% probability level.  A view, in projection down the a axis, of the unit-cell contents of (I). The C-H···O and π-π interactions are shown as orange and purple blue dashed lines, respectively.

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