2,4-Dichloro-6-methoxy­quinoline

Abstract

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,

• 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) ų

• 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[F ² > 2σ(F ²)] = 0.065

• wR(F ²) = 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 ▶).

Supplementary Material

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

supplementary crystallographic information

Comment

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.

Experimental

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

Refinement

All the H atoms were positioned geometrically and refined using a riding model [C—H = 0.97 Å and U_iso(H) = 1.5U_eq(C) for methyl and C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C) for all other H atoms.

Figures

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.

Crystal data

C10H7Cl2NO	Z = 2
Mr = 228.07	F(000) = 232
Triclinic, P1	Dx = 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

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

Refinement

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(Fo2) + (0.0844P)2 + 0.6982P] where P = (Fo2 + 2Fc2)/3
1782 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 0.38 e Å−3
0 restraints	Δρmin = −0.64 e Å−3

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 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 (Ų)

	x	y	z	Uiso*/Ueq
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 (Ų)

	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, °)

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)