Ethyl 3,7-dichloro­quinoline-8-carboxyl­ate

Zhu, F.; An, L.-T.; Xia, M.; Zhou, J.-F.

doi:10.1107/S1600536808034995

organic compounds

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ISSN: 2056-9890

Volume 64| Part 11| November 2008| Page o2241

doi:10.1107/S1600536808034995

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Ethyl 3,7-dichloroquinoline-8-carboxylate

Fengxia Zhu,^a Li-Tao An,^a ^* Min Xia ^a and Jian-Feng Zhou ^a

^aJiangsu Key Laboratory for the Chemistry of Low-dimensional Materials, Department of Chemistry, Huaiyin Teachers College, Huaian 223300, Jiangsu Province, People's Republic of China
^*Correspondence e-mail: annleet@126.com

(Received 8 October 2008; accepted 28 October 2008; online 31 October 2008)

The title compound, C₁₂H₉Cl₂NO₂, was prepared by the esterification of 3,7-dichloroquinoline-8-carboxylic acid with triethyl phosphite. The crystal structure is stabilized by aromatic π–π stacking between the benzene and the pyridine rings of neighbouring molecules [centroid–centroid distances = 3.716 (2) and 3.642 (2) Å]. In addition, weak intermolecular C—H⋯N hydrogen bonds are present in the structure.

Related literature

For the use of 3,7-dichloroquinoline-8-carboxylic acid as a herbicide, see: Nuria et al. (1997 ); Pornprom et al. (2006 ); Sunohara & Matsumoto (2004 ); Tresch & Grossmann (2002 ). For the usual preparative route, see: Yang et al. (2002 ). For related complexes, see: An et al. (2008 ); Che et al. (2005 ); Guo (2008 ); Li et al. (2008 ); Turel et al. (2004 ); Zhang et al. (2007 ). For 3,7-dichloroquinoline-8-carboxylic acid derivatives, see: Liang et al. (2006 );

Experimental

Crystal data

C₁₂H₉Cl₂NO₂
M_r = 270.10
Tetragonal, I 4₁ /a
a = 25.4806 (3) Å
c = 7.3497 (2) Å
V = 4771.87 (15) Å³
Z = 16
Mo Kα radiation
μ = 0.53 mm⁻¹
T = 296 (2) K
0.10 × 0.08 × 0.06 mm

Data collection

Bruker SMART APEX2 diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ) T_min = 0.950, T_max = 0.969
19332 measured reflections
2750 independent reflections
1625 reflections with I > 2σ(I)
R_int = 0.045

Refinement

R[F² > 2σ(F²)] = 0.043
wR(F²) = 0.117
S = 1.05
2750 reflections
155 parameters
H-atom parameters constrained
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H11A⋯N1ⁱ	0.97	2.46	3.299 (3)	145
Symmetry code: (i) $[-y+{\script{5\over 4}}, x+{\script{1\over 4}}, -z+{\script{5\over 4}}]$ .

Data collection: APEX2 (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: SHELXS97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808034995/lx2075sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808034995/lx2075Isup2.hkl

checkCIF report

Comment top

Quinclorac (3,7-dichloroquinoline-8-carboxylic acid) is one of the most effective herbicides (Nuria et al., 1997; Pornprom et al., 2006; Sunohara & Matsumoto, 2004; Tresch & Grossmann, 2002). Usually, it was prepared via Skraup cyclization from 2-methyl-3- chloroaniline, followed by chlorination and oxidation (Yang et al., 2002). Furthermore, quinolinecarboxylates can chelate to metal atoms, forming the complexes, such as trans-Dimethanolbis(quinoline-8-carboxylato-κ²N,O)- cobalt(II) (Che et al.,2005),catena-Poly[nickel(II)-bis(µ-3,7-dichloroquinoline-8-χarboxylato-κ³N,O:O')] (Zhang et al., 2007), catena-Poly[cobalt(II)-bis (l-3,7-dichloroquinoline-8-carboxylato-κ³N,O:O')] (Li et al., 2008). More recently, we also have reported a Zinc-quinclorac complex (An et al., 2008) and quinclorac (Guo, 2008). But the derivatives of 3,7-dichloroquinoline-8-carboxylic acid have been less reported (Liang et al., 2006). Here we report the crystal structure of the title compound, ethyl 3,7-dichloroquinoline-8-carboxylate (I) (Fig. 1).

In the title compound (I), as shown in Fig. 1, the plane (O1—C10—O2—C11) is nearly vertical to the quinoline ring, in which the dihedral angel is 86.6 (1). The quinoline unit is essentially planar, with a mean deviation of 0.007 (2) Å from the least-squares plane defined by the ten constituent atoms. The molecular packing (Fig. 2) is stabilized by aromatic π—π stackings between the benzene and the pyridine rings of the adjacent molecules. The Cg1···Cg2ⁱⁱ and Cg1···Cg2ⁱⁱⁱ distances are 3.716 (2) and 3.642 (2) Å (Fig. 2; Cg1 and Cg2 are the centroids of the C1/C2/C3/C4/C9/C8 benzene ring and the N1/C7/C6/C5/C9/C8 pyridine ring, respectively, symmetry code as in Fig. 2). The crystal structure is further stabilized by intermolecular C11—H11A···Nⁱ hydrogen bonds (Fig. 2 and Table 1; symmetry code as in Fig. 2).

Related literature top

For the use of 3,7-dichloroquinoline-8-carboxylic acid as a herbicide, see: Nuria et al. (1997); Pornprom et al. (2006); Sunohara & Matsumoto (2004); Tresch & Grossmann (2002). For the usual preparative route, see: Yang et al. (2002). For related complexes, see: An et al. (2008); Che et al. (2005); Guo (2008); Li et al. (2008); Turel et al. (2004); Zhang et al. (2007). For 3,7-dichloroquinoline-8-carboxylic acid derivatives, see: Liang et al. (2006);

Experimental top

Ethyl 3,7-dichloroquinoline-8-carboxylate was obtained from the reaction of 3,7-dichloroquinoline-8-carboxylic acid with triethyl phosphite in refluxing condition. After recrystallization from ethanol, then it was dissolved the mixture of acetone/petroleum ether (1:4, V/V). The suitable single-crystal for X-ray analysis was obtained by slow evaporation.

Computing details top

Data collection: APEX2 (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: SHELXS97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. π—π stackings and C—H···N interactions (dotted lines) in the title compound. Cg denotes ring centroid. [Symmetry code: (i) -y+5/4, x+1/4, -z+5/4; (ii) -x+1, -y+1, -z+2; (iii)-x+1, -y+1, -z+1.]

Ethyl 3,7-dichloroquinoline-8-carboxylate top

Crystal data top

C₁₂H₉Cl₂NO₂	D_x = 1.504 Mg m⁻³
M_r = 270.10	Melting point: not measured K
Tetragonal, I4₁/a	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -I_4ad	Cell parameters from 2208 reflections
a = 25.4806 (3) Å	θ = 1.6–26.0°
c = 7.3497 (2) Å	µ = 0.53 mm⁻¹
V = 4771.87 (15) Å³	T = 296 K
Z = 16	Needle, colorless
F(000) = 2208	0.10 × 0.08 × 0.06 mm

Data collection top

Bruker SMART APEX2 diffractometer	2750 independent reflections
Radiation source: fine-focus sealed tube	1625 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.045
Detector resolution: 10.0 pixels mm^-1	θ_max = 27.5°, θ_min = 1.6°
ϕ and ω scans	h = −32→33
Absorption correction: multi-scan (SADABS; Bruker, 1999)	k = −33→32
T_min = 0.950, T_max = 0.969	l = −9→9
19332 measured reflections

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.117	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0469P)² + 1.2301P] where P = (F_o² + 2F_c²)/3
2750 reflections	(Δ/σ)_max < 0.001
155 parameters	Δρ_max = 0.20 e Å⁻³
0 restraints	Δρ_min = −0.25 e Å⁻³

Crystal data top

C₁₂H₉Cl₂NO₂	Z = 16
M_r = 270.10	Mo Kα radiation
Tetragonal, I4₁/a	µ = 0.53 mm⁻¹
a = 25.4806 (3) Å	T = 296 K
c = 7.3497 (2) Å	0.10 × 0.08 × 0.06 mm
V = 4771.87 (15) Å³

Data collection top

Bruker SMART APEX2 diffractometer	2750 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1999)	1625 reflections with I > 2σ(I)
T_min = 0.950, T_max = 0.969	R_int = 0.045
19332 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.043	0 restraints
wR(F²) = 0.117	H-atom parameters constrained
S = 1.06	Δρ_max = 0.20 e Å⁻³
2750 reflections	Δρ_min = −0.25 e Å⁻³
155 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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	0.65771 (2)	0.53635 (3)	0.60570 (9)	0.0725 (2)
Cl2	0.34654 (3)	0.47136 (3)	0.89519 (10)	0.0809 (3)
O1	0.57642 (7)	0.63042 (6)	0.8389 (2)	0.0714 (5)
O2	0.55721 (6)	0.62556 (5)	0.5418 (2)	0.0560 (4)
N1	0.46789 (7)	0.56227 (7)	0.7898 (3)	0.0535 (5)
C1	0.55677 (8)	0.54727 (8)	0.7053 (3)	0.0479 (5)
C2	0.59627 (8)	0.51296 (8)	0.6642 (3)	0.0511 (5)
C3	0.58827 (9)	0.45826 (9)	0.6676 (3)	0.0582 (6)
H3	0.6157	0.4356	0.6390	0.070*
C4	0.54076 (9)	0.43888 (9)	0.7125 (3)	0.0594 (6)
H4	0.5358	0.4027	0.7144	0.071*
C5	0.44775 (9)	0.45445 (8)	0.8039 (3)	0.0574 (6)
H5	0.4405	0.4187	0.8107	0.069*
C6	0.40972 (9)	0.49023 (9)	0.8394 (3)	0.0555 (6)
C7	0.42156 (9)	0.54368 (9)	0.8316 (3)	0.0577 (6)
H7	0.3949	0.5675	0.8577	0.069*
C8	0.50652 (8)	0.52712 (8)	0.7514 (3)	0.0458 (5)
C9	0.49847 (8)	0.47219 (8)	0.7565 (3)	0.0492 (5)
C10	0.56464 (8)	0.60545 (8)	0.7069 (3)	0.0505 (5)
C11	0.56478 (9)	0.68194 (8)	0.5254 (3)	0.0609 (6)
H11A	0.5999	0.6915	0.5639	0.073*
H11B	0.5398	0.7004	0.6015	0.073*
C12	0.55684 (13)	0.69615 (10)	0.3318 (4)	0.0967 (10)
H12A	0.5809	0.6766	0.2574	0.145*
H12B	0.5630	0.7330	0.3160	0.145*
H12C	0.5215	0.6880	0.2967	0.145*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0602 (4)	0.0814 (5)	0.0760 (5)	0.0005 (3)	0.0113 (3)	−0.0024 (3)
Cl2	0.0661 (4)	0.1000 (5)	0.0765 (5)	−0.0247 (4)	−0.0006 (3)	0.0114 (4)
O1	0.0916 (13)	0.0584 (10)	0.0642 (12)	−0.0132 (9)	−0.0061 (9)	−0.0109 (8)
O2	0.0650 (10)	0.0406 (8)	0.0624 (11)	−0.0065 (7)	−0.0037 (8)	0.0032 (7)
N1	0.0524 (11)	0.0480 (10)	0.0601 (12)	0.0009 (9)	−0.0024 (9)	0.0023 (8)
C1	0.0560 (13)	0.0447 (12)	0.0430 (13)	−0.0014 (10)	−0.0049 (10)	0.0001 (9)
C2	0.0580 (13)	0.0529 (13)	0.0424 (12)	0.0009 (10)	−0.0021 (10)	−0.0015 (10)
C3	0.0704 (16)	0.0530 (14)	0.0511 (14)	0.0128 (11)	−0.0018 (11)	−0.0042 (10)
C4	0.0804 (17)	0.0423 (12)	0.0555 (15)	0.0022 (12)	−0.0030 (12)	−0.0035 (10)
C5	0.0778 (17)	0.0462 (12)	0.0483 (14)	−0.0158 (12)	−0.0057 (11)	0.0036 (10)
C6	0.0584 (14)	0.0637 (15)	0.0445 (13)	−0.0129 (11)	−0.0065 (10)	0.0043 (10)
C7	0.0557 (14)	0.0595 (14)	0.0578 (15)	0.0034 (11)	−0.0035 (11)	0.0037 (11)
C8	0.0567 (13)	0.0418 (12)	0.0389 (12)	0.0007 (10)	−0.0072 (9)	0.0002 (9)
C9	0.0667 (15)	0.0412 (12)	0.0397 (13)	−0.0033 (10)	−0.0077 (10)	0.0014 (9)
C10	0.0456 (12)	0.0497 (13)	0.0562 (15)	−0.0038 (10)	0.0016 (10)	−0.0020 (11)
C11	0.0583 (14)	0.0392 (12)	0.0851 (18)	−0.0080 (10)	0.0071 (12)	0.0011 (11)
C12	0.139 (3)	0.0547 (16)	0.097 (2)	−0.0178 (17)	−0.0243 (19)	0.0215 (15)

Geometric parameters (Å, º) top

Cl1—C2	1.729 (2)	C4—H4	0.9300
Cl2—C6	1.730 (2)	C5—C6	1.356 (3)
O1—C10	1.198 (2)	C5—C9	1.413 (3)
O2—C10	1.331 (2)	C5—H5	0.9300
O2—C11	1.454 (2)	C6—C7	1.396 (3)
N1—C7	1.309 (3)	C7—H7	0.9300
N1—C8	1.360 (2)	C8—C9	1.415 (3)
C1—C2	1.367 (3)	C11—C12	1.482 (3)
C1—C8	1.420 (3)	C11—H11A	0.9700
C1—C10	1.496 (3)	C11—H11B	0.9700
C2—C3	1.409 (3)	C12—H12A	0.9600
C3—C4	1.348 (3)	C12—H12B	0.9600
C3—H3	0.9300	C12—H12C	0.9600
C4—C9	1.409 (3)

C10—O2—C11	115.91 (17)	C6—C7—H7	118.1
C7—N1—C8	117.60 (18)	N1—C8—C9	122.72 (19)
C2—C1—C8	119.03 (18)	N1—C8—C1	117.63 (17)
C2—C1—C10	122.47 (18)	C9—C8—C1	119.65 (19)
C8—C1—C10	118.49 (18)	C4—C9—C5	124.3 (2)
C1—C2—C3	121.5 (2)	C4—C9—C8	118.6 (2)
C1—C2—Cl1	120.06 (16)	C5—C9—C8	117.1 (2)
C3—C2—Cl1	118.45 (17)	O1—C10—O2	124.7 (2)
C4—C3—C2	119.8 (2)	O1—C10—C1	124.5 (2)
C4—C3—H3	120.1	O2—C10—C1	110.81 (18)
C2—C3—H3	120.1	O2—C11—C12	107.63 (19)
C3—C4—C9	121.5 (2)	O2—C11—H11A	110.2
C3—C4—H4	119.3	C12—C11—H11A	110.2
C9—C4—H4	119.3	O2—C11—H11B	110.2
C6—C5—C9	119.07 (19)	C12—C11—H11B	110.2
C6—C5—H5	120.5	H11A—C11—H11B	108.5
C9—C5—H5	120.5	C11—C12—H12A	109.5
C5—C6—C7	119.6 (2)	C11—C12—H12B	109.5
C5—C6—Cl2	121.59 (18)	H12A—C12—H12B	109.5
C7—C6—Cl2	118.82 (19)	C11—C12—H12C	109.5
N1—C7—C6	123.9 (2)	H12A—C12—H12C	109.5
N1—C7—H7	118.1	H12B—C12—H12C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11A···N1ⁱ	0.97	2.46	3.299 (3)	145

Symmetry code: (i) −y+5/4, x+1/4, −z+5/4.

Experimental details

Crystal data
Chemical formula	C₁₂H₉Cl₂NO₂
M_r	270.10
Crystal system, space group	Tetragonal, I4₁/a
Temperature (K)	296
a, c (Å)	25.4806 (3), 7.3497 (2)
V (Å³)	4771.87 (15)
Z	16
Radiation type	Mo Kα
µ (mm⁻¹)	0.53
Crystal size (mm)	0.10 × 0.08 × 0.06

Data collection
Diffractometer	Bruker SMART APEX2 diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 1999)
T_min, T_max	0.950, 0.969
No. of measured, independent and observed [I > 2σ(I)] reflections	19332, 2750, 1625
R_int	0.045
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.117, 1.06
No. of reflections	2750
No. of parameters	155
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.25

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11A···N1ⁱ	0.97	2.46	3.299 (3)	144.9

Symmetry code: (i) −y+5/4, x+1/4, −z+5/4.

Acknowledgements

This work was supported financially by Jiangsu Key Laboratory for the Chemistry of Low-dimensional Materials.

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