2,4-Dichloro-7,8-dimethyl­quinoline

R Subashini; F Nawaz Khan; T Rajashekar Reddy; Venkatesha R Hathwar; Mehmet Akkurt

doi:10.1107/S1600536810020386

. 2010 Jun 5;66(Pt 7):o1535. doi: 10.1107/S1600536810020386

2,4-Dichloro-7,8-dimethylquinoline

R Subashini ^a, F Nawaz Khan ^a, T Rajashekar Reddy ^a, Venkatesha R Hathwar ^b, Mehmet Akkurt ^c,^*

PMCID: PMC3006798 PMID: 21587784

Abstract

There are two independent molecules in the asymmetric unit of the title compound, C₁₁H₉Cl₂N, both of which are essentially planar [maximum deviations of 0.072 (5) and 0.072 (7) Å]. In the crystal structure, weak π–π stacking interactions [centroid-centroid distances = 3.791 (3) Å and 3.855 (3) Å] link pairs of molecules.

Related literature

For the properties and applications of related compounds, see: Biavatti et al. (2002 ▶); Fournet et al. (1981 ▶); McCormick et al. (1996 ▶); Towers et al. (1981 ▶); Ziegler & Gelfert (1959 ▶). For similar crystal structures, see: Subashini et al. (2009 ▶); Somvanshi et al. (2008 ▶).

Experimental

Crystal data

C₁₁H₉Cl₂N
M _r = 226.09
Orthorhombic,
a = 20.3054 (9) Å
b = 3.9992 (2) Å
c = 25.5743 (11) Å
V = 2076.77 (17) Å³
Z = 8
Mo Kα radiation
μ = 0.58 mm⁻¹
T = 295 K
0.30 × 0.24 × 0.15 mm

Data collection

Oxford Xcalibur Eos (Nova) CCD detector diffractometer
Absorption correction: multi-scan (CrysAlis PRO RED; Oxford Diffraction, 2009 ▶) T _min = 0.845, T _max = 0.918
19807 measured reflections
4009 independent reflections
2599 reflections with I > 2σ(I)
R _int = 0.048

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.119
S = 0.94
4009 reflections
257 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: Flack (1983 ▶), 1943 Friedel pairs
Flack parameter: 0.15 (10)

Data collection: CrysAlis PRO CCD (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO CCD; data reduction: CrysAlis PRO RED (Oxford Diffraction, 2009 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810020386/vm2029sup1.cif

e-66-o1535-sup1.cif^{(23.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810020386/vm2029Isup2.hkl

e-66-o1535-Isup2.hkl^{(196.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

We thank the Department of Science and Technology, India, for use of the CCD facility set up under the FIST–DST program at SSCU, IISc. We also thank Professor T. N. Guru Row, IISc, Bangalore, for his help with the data collection. FNK thanks the DST for Fast Track Proposal funding.

supplementary crystallographic information

Comment

A wide range of medicinal properties have already been identified for compounds containing the quinoline ring system including antiprotozoal (Fournet et al., 1981), antibacterial (Towers et al., 1981), antifungal (Biavatti et al., 2002) and antiviral activities (McCormick et al., 1996). Reaction of aniline with malonic acid in an excess of phosphorus oxychloride at reflux to give 2,4-dichloroquinoline was first reported by Ziegler & Gelfert (1959). A similar derivative of quinoline was synthesized from the mixture of p-toluidine and malonic acid in a one-pot reaction from an aryl amine, malonic acid and phosphorous oxychloride and its cytotoxicity has been reported (Somvanshi et al., 2008). Another derivative of quinoline prepared from p-anisidine and phosphorous oxychloride has been reported (Subashini et al., 2009). In continuous of our work, the crystal structure of another derivative is reported in this paper.

The molecules A (Cl1/Cl2/N1/C1–C11) and B (Cl3/Cl4/N2/C12–C22) in the asymmetric unit of the title compound (I) are shown in Fig. 1. In both molecules A and B, the bond lengths and angles are comparable with those of similar structures (Somvanshi et al., 2008; Subashini et al., 2009). The molecules A and B are essentially planar, except the H atoms of their methyl groups, with maximum deviations of 0.072 (5)Å for C10 and 0.072 (7)Å for C21, respectively. Fitting of the non-H atoms of molecules A and B results in an r.m.s. fit of 0.063 Å). The least-squares plane through molecule A makes a dihedral angle of 56.72 (14)° with that of molecule B.

Weak intramolecular C—H···Cl and C—H···N interactions contribute to the stabilization of the molecular conformation of (I) (Table 1). In the crystal structure, weak π-π stacking interactions [Cg1···Cg2(x, 1 + y, z) = 3.791 (3) Å and Cg4···Cg5 (x, 1 + y, z) = 3.855 (3) Å; where Cg1, Cg2, Cg4 and Cg5 are centroids of the N1/C1–C4/C9, C4–C9, N2/C12–C15/C20 and C15–C20 rings, respectively] link pairs of molecules. In the structure, no classical hydrogen bonds are observed. Fig. 2 shows the crystal packing down the b axis.

Experimental

2,3-Dimethylaniline (10 mmol) and malonic acid (10 mmol) were heated under reflux in phosphorus oxychloride (30 ml), with stirring, for 5 h. The mixture was cooled, poured into crushed ice with vigorous stirring and then made alkaline with 5 M sodium hydroxide. Filtration gave the crude product as a brown solid. Column chromatography (95:5 hexane–EtOAc) yielded the pure 2,4-dichloro-7,8-dimethylquinoline. White needles of the synthesized compound have been grown from DMSO.