2-Methoxy-4-(2-methoxyphenyl)-5,6,7,8,9,10-hexahydrocycloocta[b]pyridine-3-carbonitrile

In the title compound, C20H22N2O2, the central pyridine ring forms a dihedral angle of 76.32 (8)° with the pseudo-axial benzene ring. The cyclooctane ring adopts a twisted boat chair conformation. In the crystal, weak intermolecular C—H⋯π interactions between inversion-related molecules result in the formation of linear double chains along the b-axis direction.

In the title compound, C 20 H 22 N 2 O 2 , the central pyridine ring forms a dihedral angle of 76.32 (8) with the pseudo-axial benzene ring. The cyclooctane ring adopts a twisted boat chair conformation. In the crystal, weak intermolecular C-HÁ Á Á interactions between inversion-related molecules result in the formation of linear double chains along the b-axis direction.

Related literature
For the biological activities of substituted pyridine derivatives, see: Yao et al. (1994); Lohaus & Dittmar (1968). For a description of structure correlation, bond lengths and angles, see: Allen et al. (1987). For ring conformation parameters, see: Cremer & Pople (1975). The linearity of the cyano group seen in the title compound is typical of this class of 2-oxopyridine-3carbonitrile compounds, see: Black et al. (1992); Hussain et al. (1996).

Experimental
Preparation: A mixture of cyclooctanone (1 mmol), 2-methoxy benzaldehyde (1 mmol) and malononitrile (1 mmol) were taken in methanol (10 ml) to which lithium ethoxide (1 equiv) was added. The reaction mixture was heated under reflux for 2-3 h. After completion of the reaction (TLC), the reaction mixture was poured into crushed ice and extracted with ethyl acetate. The excess solvent was removed under vacuum and the residue was subjected to column chromatography using petroleum ether/ ethyl acetate mixture (95:5 v/v) as eluent to obtain pure product. Melting point:151-156 °C, Yield: 71%.

Refinement
H atoms were placed at calculated positions and allowed to ride on their carrier atoms with C-H = 0.93-0.98 Å and with U iso = 1.2U eq (C, N) for N, CH 2 and CH atoms and U iso = 1.5U eq (C) for CH 3 atoms.  The molecular structure of compound showing 30% probability displacement ellipsoids and the atom-numbering scheme. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.24 e Å −3 Δρ min = −0.29 e Å −3

Special details
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.