2-Chloro-7-methyl-12-phenyldibenzo[b,g][1,8]naphthyridin-11(6H)-one

In the title compound, C23H15ClN2O, the fused ring system is planar: the deviation of all the non-H atoms from the plane through all four fused rings is less than 0.31 Å. The plane of the phenyl ring is inclined at 71.78 (5)° to the mean plane of the 1,8-naphthrydine ring system. The crystal structure is devoid of any classical hydrogen bonds but π–π interactions are present.

In the title compound, C 23 H 15 ClN 2 O, the fused ring system is planar: the deviation of all the non-H atoms from the plane through all four fused rings is less than 0.31 Å . The plane of the phenyl ring is inclined at 71.78 (5) to the mean plane of the 1,8-naphthrydine ring system. The crystal structure is devoid of any classical hydrogen bonds butinteractions are present.

Related literature
For the biological activity of [1,8]

Comment
In general, nitrogen containing heterocyclic compounds play important roles in biological activities. Among such compounds, [1,8]naphthyridine derivatives represent the most active class of compounds possessing a wide spectrum of biological activities, such as antibacterial (Miyamoto et al., 1984, Cooper et al., 1992, antitumour (Chen et al., 1997), antimalarial (Balin et al., 1984), antifungal (Nadaraj et al., 2009), anti-inflammatory (Kuroda et al., 1992, antihypertensive activities etc. This paper describes the crystal structure of the title compound, which will help us in our studies on drug design. The title compound consists of a [1,8]napthyridine core with methyl, chloro-phenyl and phenyl group substituents ( Fig.   1). The dihedral angle between the two fused rings of the napthyridine moiety is found to be 3.08 (3)°, indicating that it is almost planar. The phenyl ring is inclined to the mean plane of the [1,8]naphthrydine ring system by 72.51 (3)°. The bond lengths of the formal single bonds, and C2-Cl1 = 1.7392 (14) and C12-O1 = 1.2240 (14) Å, are in normal ranges (Allen et al., 1987), and similar to those observed in other naphthrydine derivatives (Sivakumar et al., 2003;Seebacher et al., 2010).
The crystal packing of the molecules in the crystal is influenced by π-π interactions and van der Waals forces ( Fig. 2 and Table 1).

Experimental
The title compund was synthesized according to the published procedure (Manoj et al., 2009). 2[(2'-Benzoyl-4'chlorophenyl)amino]-4-chloroquinoline (2 mmol) was added to polyphosphoric acid (6 g of P 2 O 5 in 3 ml of H 3 PO 4 ) and heated at 478-483 K for 5 h. The reaction was monitored by using TLC. After completion of the reaction, the reaction mixture was poured into ice water and extracted with ethyl acetate. It was then purified by column chromatography using silica gel and the product eluted with a petroleum ether:ethyl acetate (96:4) mixture, to give the title compound as a pale yellow solid. It was recrystallized using methanol.

Refinement
The H-atoms were positioned geometrically and treated as riding atoms: C-H = 0.93 Å H-aromatic, C-H = 0.96 Å H-methyl, and N-H = 0.86 Å, with U iso = k×U eq (parent C or N-atom), where k = 1.5 for methyl H-atoms, and = 1.2 for all other H-atoms.   Table 1 for details].

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