7-Methoxy-2-phenylquinoline-3-carbaldehyde

In the title molecule, C17H13NO2, the phenyl ring is inclined to the quinoline ring system by 43.53 (4)°. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming double-stranded chains propagating along [011]. These chains are linked via π–π interactions involving inversion-related quinoline rings; the shortest centroid–centroid distance is 3.6596 (17) Å.

In the title molecule, C 17 H 13 NO 2 , the phenyl ring is inclined to the quinoline ring system by 43.53 (4) . In the crystal, molecules are linked via C-HÁ Á ÁO hydrogen bonds, forming double-stranded chains propagating along [011]. These chains are linked viainteractions involving inversion-related quinoline rings; the shortest centroid-centroid distance is 3.6596 (17) Å .
Thanks are due to the MESRS (Ministé re de l'Enseignement Supé rieur et de la Recherche Scientifique -Algé rie) for financial support. We are grateful to Dr Roisnel Thierry from the Centre de Difractomé trie de Rennes, Université de Rennes 1, France, for his technical assistance with the data collection. Heterocyclic compounds have so far been synthesized mainly due to the wide range of biological activities. Quinoline derivatives have considerable interest since many years due to the presence of this skeleton in a large number of bioactive compounds and natural products (Montalban, 2011;Wang et al., 2011). In other hand, it has been well established that presence of aryl ring at second position of quinoline moiety gives a very good antibacterial property to the target molecule and plays a significant role in development of new antibacterials (Nilsson et al., 2008;Elliott et al., 2006). These derivatives were found to be useful biological targets, and at present they attained much attention in the development of new drugs (Metallidis et al., 2007;Kaila et al., 2007). Following of our previous works related to the use of substituted 2-chloro-3-formylquinolines as precursors of different quinoline-containing heterocycles (Bouraiou et al., 2011;Hayour et al., 2011), we have recently reported preparations and antibacterial screening of series of compounds carrying diverse functionalities such as an amine, amide, ester group, heterocylic unit linked to the 2-phenylquinoline entity (Benzerka et al., 2011(Benzerka et al., , 2012(Benzerka et al., , 2013. We report herein the synthesis and single-crystal X-ray structure of 7-methoxy-2-phenylquinoline-3-carbaldehyde (I).
The molecular geometry and the atom-numbering scheme of (I) are shown in Fig. 1. The asymmetric unit of (I) consists of 2-phenylquinoline linked to 7-methoxy and 3-carbaldehyde. The substituted phenyl ring forms dihedral angle of 43.53 (4)° with heterocyclic ring of quinoline. The crystal packing can be described as alternating layers parallel to the (210) (Fig. 2). It is stabilized by C-H···O hydrogen bond ( Fig. 3; Table. 1), and strong π-π stacking interactions between quinoline rings with a centroid-centroid distance from 3.6596 (17)Å to 4.0726 (18)Å. These interaction bonds link the molecules within the layers and also link the layers together, reinforcing the cohesion of the structure.

Experimental
A mixture of 2-chloro-7-methoxyquinoline-3-carbaldehyde (l mmol) and phenylboronic acid (1.2 mmol) in 4 ml DME was stirred under nitrogen. Palladium acetate (0.01 mmol), aq. K 2 CO 3 (3 mmol in 3.75 ml of H 2 O) and triphenylphosphine (0.04 mmol) were added and the mixture was refluxed for 2 h. After completion, the reaction mixture was cooled to room temperature, diluting with EtOAc and filtering through a small bed of celite. The organic layers were collected, combined, washed with water and saturated aq NaHCO 3 (2x10 ml), dried over anhydrous Na 2 SO 4 and concentrated under vacuum. The crude compound was purified by column chromatography on silica gel using ethyl acetate/ hexane (1/2) to afford the desired product as yellow solid. Single crystals suitable for the X-ray diffraction analysis were obtained by dissolving the pure compound in an ethyl acetate/hexane mixture and allowing the solution to slowly evaporate at room temperature.

Refinement
. Approximate positions for all the H atoms were first obtained from the difference electron density map. However, the H atoms were situated into idealized positions and the H-atoms have been refined within the riding atom approximation.

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.