2,4-Dichloro-6-methoxy­quinoline

Subashini, R.; Hathwar, V.R.; Manivel, P.; Prabakaran, K.; Khan, F.N.

doi:10.1107/S1600536809002402

organic compounds

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ISSN: 2056-9890

Volume 65| Part 2| February 2009| Page o370

doi:10.1107/S1600536809002402

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2,4-Dichloro-6-methoxyquinoline

R. Subashini,^a Venkatesha R. Hathwar,^b P. Manivel,^a K. Prabakaran ^a and F. Nawaz Khan ^a ^*

^aOrganic Chemistry Division, School of Science and Humanities, VIT University, Vellore 632 014, Tamil Nadu, India, and ^bSolid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, Karnataka, India
^*Correspondence e-mail: nawaz_f@yahoo.co.in

(Received 14 January 2009; accepted 19 January 2009; online 23 January 2009)

The title compound, C₁₀H₇Cl₂NO, features a planar molecule, excluding the methyl H atoms [maximum deviation = 0.0385 (1) Å]. The crystal packing is stabilized by π–π stacking interactions across inversion centres [centroid-to-centroid distance = 3.736 (3) Å].

Related literature

For general background, see: Fournet et al. (1981 ) and references cited therein; Towers et al. (1981 ); Biavatti et al. (2002 ); McCormick et al. (1996 ); Ziegler & Gelfert, (1959 ). For related crystal structures, see: Somvanshi et al. (2008 ).

Experimental

Crystal data

C₁₀H₇Cl₂NO
M_r = 228.07
Triclinic, $[P \overline 1]$
a = 7.431 (2) Å
b = 8.889 (2) Å
c = 9.083 (4) Å
α = 116.660 (19)°
β = 102.301 (2)°
γ = 104.150 (14)°
V = 482.5 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.63 mm⁻¹
T = 290 (2) K
0.25 × 0.18 × 0.15 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.811, T_max = 0.909
5720 measured reflections
1782 independent reflections
1272 reflections with I > 2σ(I)
R_int = 0.054

Refinement

R[F² > 2σ(F²)] = 0.065
wR(F²) = 0.197
S = 1.15
1782 reflections
128 parameters
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.64 e Å⁻³

Data collection: SMART (Bruker, 2004 ); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1999 ) and CAMERON (Watkin et al., 1993 ); software used to prepare material for publication: PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809002402/bt2852sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809002402/bt2852Isup2.hkl

checkCIF report

Comment top

A wide range of medicinal properties have already been identified in 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 & Subashini et al., 2008). In continuous of our work, crystal structure of another derivative is reported in this paper.

The crystal packing is stabilized by intermolecular π–π [Cg1···Cg1 and Cg2···Cg2] stacking interactions with shortest perpendicular distances between isochinoline groups of 3.470 Å and 3.497 Å, the slippages between these ring systems are 1.283 Å and 1.178 Å, the distances between the centroids of the six-membered carbon rings are 3.700 (3) Å and 3.690 (3) Å with the symmetry code (2 - x, -y, 1 - z) and (1 - x, -y, 1 - z), respectively. Further, another intermolecular π–π [Cg1···Cg2] stacking interactions with a shortest perpendicular distance of 3.476 Å between the two rings and the distance between the centroids of the six-membered carbon rings is 3.736 (3) Å with the symmetry code (2 - x, -y, -z). Cg1 and Cg2 are the centroids of N1—C1—C2—C3—C4—C8—C9 ring and C4–C9 ring respectively.

Related literature top

For general background, see: Fournet et al. (1981) and references cited therein; Towers et al. (1981); Biavatti et al. (2002); McCormick et al. (1996); Ziegler & Gelfert, (1959). For related crystal structures, see: Somvanshi et al. (2008).

Experimental top

p-Anisidine (10 mmol) and malonic acid (15 mmol) were heated under reflux in phosphorus oxychloride (20 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. A Column chromatography (95:5 hexane–EtOAc) yielded the pure dichloroquinoline as off-white needles

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1999) and CAMERON (Watkin et al., 1993); software used to prepare material for publication: PLATON (Spek, 2003).

Figures top

	Fig. 1. ORTEP diagram of the title compound with 50% probability displacement ellipsoids.
	Fig. 2. The crystal packing diagram of the title compound. The dotted lines indicate π–π interactions. All H atoms have been omitted for clarity.

2,4-Dichloro-6-methoxyquinoline top

Crystal data top

C₁₀H₇Cl₂NO	Z = 2
M_r = 228.07	F(000) = 232
Triclinic, P1	D_x = 1.570 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.431 (2) Å	Cell parameters from 856 reflections
b = 8.889 (2) Å	θ = 1.9–20.7°
c = 9.083 (4) Å	µ = 0.63 mm⁻¹
α = 116.660 (19)°	T = 290 K
β = 102.301 (2)°	Block, colourless
γ = 104.150 (14)°	0.25 × 0.18 × 0.15 mm
V = 482.5 (3) Å³

Data collection top

Bruker SMART CCD area-detector diffractometer	1782 independent reflections
Radiation source: fine-focus sealed tube	1272 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.054
ϕ and ω scans	θ_max = 25.5°, θ_min = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→8
T_min = 0.811, T_max = 0.909	k = −10→10
5720 measured reflections	l = −11→11

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.197	H-atom parameters constrained
S = 1.15	w = 1/[σ²(F_o²) + (0.0844P)² + 0.6982P] where P = (F_o² + 2F_c²)/3
1782 reflections	(Δ/σ)_max < 0.001
128 parameters	Δρ_max = 0.38 e Å⁻³
0 restraints	Δρ_min = −0.64 e Å⁻³

Crystal data top

C₁₀H₇Cl₂NO	γ = 104.150 (14)°
M_r = 228.07	V = 482.5 (3) Å³
Triclinic, P1	Z = 2
a = 7.431 (2) Å	Mo Kα radiation
b = 8.889 (2) Å	µ = 0.63 mm⁻¹
c = 9.083 (4) Å	T = 290 K
α = 116.660 (19)°	0.25 × 0.18 × 0.15 mm
β = 102.301 (2)°

Data collection top

Bruker SMART CCD area-detector diffractometer	1782 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1272 reflections with I > 2σ(I)
T_min = 0.811, T_max = 0.909	R_int = 0.054
5720 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.065	0 restraints
wR(F²) = 0.197	H-atom parameters constrained
S = 1.15	Δρ_max = 0.38 e Å⁻³
1782 reflections	Δρ_min = −0.64 e Å⁻³
128 parameters

Special details top

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.3126 (2)	1.55448 (15)	0.76004 (16)	0.0555 (4)
Cl2	0.2701 (2)	0.98994 (16)	0.84707 (16)	0.0592 (5)
N1	0.2689 (5)	1.2373 (5)	0.5081 (5)	0.0400 (9)
O1	0.2020 (5)	0.5198 (4)	0.1887 (4)	0.0517 (8)
C1	0.2837 (6)	1.3262 (5)	0.6714 (6)	0.0383 (10)
C2	0.2849 (6)	1.2594 (5)	0.7862 (5)	0.0382 (9)
H2	0.2972	1.3312	0.9031	0.046*
C3	0.2666 (6)	1.0805 (6)	0.7130 (5)	0.0378 (9)
C4	0.2323 (6)	0.7880 (5)	0.4545 (6)	0.0380 (9)
H4	0.2318	0.7305	0.5184	0.046*
C5	0.2168 (6)	0.6950 (5)	0.2814 (6)	0.0392 (10)
C6	0.2134 (7)	0.7815 (6)	0.1824 (6)	0.0422 (10)
H6	0.1994	0.7169	0.0641	0.051*
C7	0.2302 (7)	0.9572 (6)	0.2591 (6)	0.0421 (10)
H7	0.2294	1.0119	0.1926	0.051*
C8	0.2489 (6)	1.0586 (5)	0.4363 (5)	0.0350 (9)
C9	0.2491 (6)	0.9716 (5)	0.5361 (5)	0.0344 (9)
C10	0.2067 (8)	0.4245 (7)	0.2807 (7)	0.0573 (13)
H10A	0.3330	0.4855	0.3778	0.086*
H10B	0.1897	0.3014	0.2006	0.086*
H10C	0.1007	0.4228	0.3254	0.086*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0789 (9)	0.0407 (6)	0.0592 (8)	0.0310 (6)	0.0316 (6)	0.0293 (6)
Cl2	0.0927 (11)	0.0533 (7)	0.0488 (7)	0.0298 (7)	0.0288 (6)	0.0383 (6)
N1	0.049 (2)	0.0396 (19)	0.046 (2)	0.0226 (17)	0.0195 (17)	0.0300 (17)
O1	0.070 (2)	0.0391 (16)	0.0490 (18)	0.0252 (16)	0.0202 (16)	0.0246 (15)
C1	0.038 (2)	0.035 (2)	0.047 (2)	0.0168 (18)	0.0141 (19)	0.0248 (19)
C2	0.038 (2)	0.044 (2)	0.038 (2)	0.0176 (19)	0.0164 (18)	0.0234 (19)
C3	0.040 (2)	0.042 (2)	0.041 (2)	0.0169 (18)	0.0150 (18)	0.0284 (19)
C4	0.039 (2)	0.039 (2)	0.044 (2)	0.0151 (18)	0.0138 (19)	0.0295 (19)
C5	0.039 (2)	0.035 (2)	0.045 (2)	0.0148 (18)	0.0130 (19)	0.0232 (19)
C6	0.053 (3)	0.045 (2)	0.036 (2)	0.023 (2)	0.0185 (19)	0.0234 (19)
C7	0.055 (3)	0.044 (2)	0.042 (2)	0.025 (2)	0.020 (2)	0.030 (2)
C8	0.036 (2)	0.037 (2)	0.038 (2)	0.0151 (17)	0.0127 (17)	0.0239 (18)
C9	0.032 (2)	0.036 (2)	0.039 (2)	0.0127 (17)	0.0127 (17)	0.0235 (18)
C10	0.070 (3)	0.048 (3)	0.074 (3)	0.028 (2)	0.030 (3)	0.043 (3)

Geometric parameters (Å, º) top

Cl1—C1	1.749 (4)	C4—C9	1.415 (5)
Cl2—C3	1.734 (4)	C4—H4	0.9300
N1—C1	1.293 (5)	C5—C6	1.422 (6)
N1—C8	1.372 (5)	C6—C7	1.352 (6)
O1—C5	1.359 (5)	C6—H6	0.9300
O1—C10	1.433 (5)	C7—C8	1.402 (6)
C1—C2	1.412 (5)	C7—H7	0.9300
C2—C3	1.377 (6)	C8—C9	1.432 (5)
C2—H2	0.9300	C10—H10A	0.9600
C3—C9	1.411 (6)	C10—H10B	0.9600
C4—C5	1.370 (6)	C10—H10C	0.9600

C1—N1—C8	117.4 (3)	C7—C6—H6	119.8
C5—O1—C10	117.2 (4)	C5—C6—H6	119.8
N1—C1—C2	126.7 (4)	C6—C7—C8	121.6 (4)
N1—C1—Cl1	116.3 (3)	C6—C7—H7	119.2
C2—C1—Cl1	117.0 (3)	C8—C7—H7	119.2
C3—C2—C1	115.3 (4)	N1—C8—C7	119.1 (3)
C3—C2—H2	122.3	N1—C8—C9	122.6 (4)
C1—C2—H2	122.3	C7—C8—C9	118.3 (4)
C2—C3—C9	122.4 (3)	C3—C9—C4	125.0 (4)
C2—C3—Cl2	117.9 (3)	C3—C9—C8	115.5 (3)
C9—C3—Cl2	119.6 (3)	C4—C9—C8	119.5 (4)
C5—C4—C9	120.1 (4)	O1—C10—H10A	109.5
C5—C4—H4	120.0	O1—C10—H10B	109.5
C9—C4—H4	120.0	H10A—C10—H10B	109.5
O1—C5—C4	125.8 (4)	O1—C10—H10C	109.5
O1—C5—C6	114.1 (4)	H10A—C10—H10C	109.5
C4—C5—C6	120.0 (4)	H10B—C10—H10C	109.5
C7—C6—C5	120.5 (4)

C8—N1—C1—C2	1.2 (6)	C1—N1—C8—C9	−1.6 (6)
C8—N1—C1—Cl1	179.1 (3)	C6—C7—C8—N1	178.9 (4)
N1—C1—C2—C3	−0.6 (6)	C6—C7—C8—C9	−0.2 (7)
Cl1—C1—C2—C3	−178.5 (3)	C2—C3—C9—C4	179.2 (4)
C1—C2—C3—C9	0.4 (6)	Cl2—C3—C9—C4	0.4 (6)
C1—C2—C3—Cl2	179.2 (3)	C2—C3—C9—C8	−0.8 (6)
C10—O1—C5—C4	−1.2 (6)	Cl2—C3—C9—C8	−179.6 (3)
C10—O1—C5—C6	179.3 (4)	C5—C4—C9—C3	−179.8 (4)
C9—C4—C5—O1	179.3 (4)	C5—C4—C9—C8	0.3 (6)
C9—C4—C5—C6	−1.3 (6)	N1—C8—C9—C3	1.5 (6)
O1—C5—C6—C7	−178.9 (4)	C7—C8—C9—C3	−179.5 (4)
C4—C5—C6—C7	1.6 (7)	N1—C8—C9—C4	−178.6 (4)
C5—C6—C7—C8	−0.8 (7)	C7—C8—C9—C4	0.5 (6)
C1—N1—C8—C7	179.3 (4)

Experimental details

Crystal data
Chemical formula	C₁₀H₇Cl₂NO
M_r	228.07
Crystal system, space group	Triclinic, P1
Temperature (K)	290
a, b, c (Å)	7.431 (2), 8.889 (2), 9.083 (4)
α, β, γ (°)	116.660 (19), 102.301 (2), 104.150 (14)
V (Å³)	482.5 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.63
Crystal size (mm)	0.25 × 0.18 × 0.15

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.811, 0.909
No. of measured, independent and observed [I > 2σ(I)] reflections	5720, 1782, 1272
R_int	0.054
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.065, 0.197, 1.15
No. of reflections	1782
No. of parameters	128
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.38, −0.64

Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1999) and CAMERON (Watkin et al., 1993), PLATON (Spek, 2003).

Acknowledgements

The authors thank the Department of Science and Technology, India, for use of the CCD facility set up under the IRHPA-DST programme at IISc. We thank Professor T. N. Guru Row, IISc, Bangalore, for useful crystallographic discussions. FNK thanks the DST for Fast Track Proposal funding.

References

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