Crystal structure of 2-(4-methylpiperazin-1-yl)quinoline-3-carbaldehyde

In the title compound, C15H17N3O, the aldehyde group is twisted relative to the quinoline group by17.6 (2)° due to the presence of a bulky piperazinyl group in the ortho position. The piperazine N atom attached to the aromatic ring is sp 3-hybridized and the dihedral angle between the mean planes through the the six piperazine ring atoms and through the quinoline ring system is 40.59 (7)°. Both piperazine substituents are in equatorial positions.


S1. Introduction
Quinoline and its derivatives have been well known in pharmaceutical chemistry because of their wide spectrum of biological activities and their presence in naturally occurring compounds. They have been shown to possess antimalarial (Nasveld et al., 2005), antibiotic (Eswaran et al., 2009), anticancer (Denny et al., 1983, anti-inflammatory (Muruganantham et al., 2004), antihypertensive (Maguire et al., 1994), tyrokinase PDGF-RTK inhibition (Wilson et al., 1992) and anti-HIV properties (Strekowski et al., 1991). In addition, polysubstituted quinoline can achieve hierchical self-assembly into variety of meso and nano structures with enhanced photonic and electronic properties (Gyoten et al., 2003). In this view the title compound was synthesized to study its crystal structure.

S2.1. Synthesis and crystallization
2-Chloroquinoline-3-carbaldehyde (0.42 g, 0.00351 mmol), N-methyl piperazine (0.14 g, 0.00351 mmol) and anhydrous K 2 CO 3 (1.0 g, 0.002920 mmol) were refluxed for 24 hrs in DMF. The progress of the reaction was monitored by thin layer chromatography. After the completion of the reaction, the reaction mixture was poured into water and extracted to ethyl acetate. The organic layer was washed with water, dried and concentrated under vacuum using rotary evaporator.
Single crystals of the title compound were obtained by slow evaporation of the ethyl acetate solution at room temperature (27 o C).

S2.2. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. All H atoms were positioned with idealized geometry using a riding model with C-H = 0.93-0.97 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the Ueq of the parent C atom).

S3. Results and discussion
The crystal packing of the compound does not feature any specific strong or weak intermolecular interactions.

Figure 1
Molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. 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.