(S)-Ethyl 2-[4-(6-chloro­quinoxalin-2-yl­oxy)phen­oxy]propanoate

Hu, J.; Chen, G.; Guo, L.; Wang, J.; Xu, Y.

doi:10.1107/S1600536809030074

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 65| Part 9| September 2009| Page o2082

doi:10.1107/S1600536809030074

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(S)-Ethyl 2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propanoate

Jun Hu,^a Guo-song Chen,^a Li-hua Guo,^a Ji-kui Wang ^a ^* and Yan-hua Xu ^b

^aDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China, and ^bDepartment of Safety Engineering, College of Urban Construction and Safety & Environmental Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: wjk@njut.edu.cn

(Received 14 June 2009; accepted 29 July 2009; online 8 August 2009)

In the molecule of the title compound, C₁₉H₁₇ClN₂O₄, the quinoxaline ring system is planar [maximum deviation = 0.013 (3) Å] and oriented at a dihedral angle of 80.18 (3)° with respect to the benzene ring. In the crystal structure, intermolecular C—H⋯N interactions link molecules into chains. π–π contacts between the quinoxaline systems [centroid–centroid distance = 3.654 (1) Å] may further stabilize the structure.

Related literature

The title compound has potent selective herbicidal activity against annual and perennial grass weeds, see: Sakata et al. (1985 ). For bond-length data, see: Allen et al. (1987 ).

Experimental

Crystal data

C₁₉H₁₇ClN₂O₄
M_r = 372.80
Monoclinic, P 2₁
a = 9.970 (2) Å
b = 4.4760 (9) Å
c = 20.450 (4) Å
β = 94.54 (3)°
V = 909.7 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 294 K
0.30 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.932, T_max = 0.977
3762 measured reflections
1898 independent reflections
1254 reflections with I > 2σ(I)
R_int = 0.052
3 standard reflections frequency: 120 min intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.050
wR(F²) = 0.155
S = 1.00
1898 reflections
235 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.20 e Å⁻³
Absolute structure: Flack (1983 ), 932 Friedel pairs
Flack parameter: −0.02 (18)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C19—H19A⋯N1ⁱ	0.93	2.57	3.396 (7)	149
Symmetry code: (i) $[-x+2, y-{\script{1\over 2}}, -z]$ .

Data collection: CAD-4 Software (Enraf–Nonius, 1985 ); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, Il. DOI: 10.1107/S1600536809030074/hk2712sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809030074/hk2712Isup2.hkl

checkCIF report

Comment top

The title compound has a potent selective herbicidal activity against annual and perennial grass weeds (Sakata et al., 1985). We report herein its crystal structure.

In the molecule of the title compound (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. Rings A (C6-C11), B (C13-C18) and C (N1/N2/C12/C13/C18/C19) are, of course, planar, and they are oriented at dihedral angles of A/B = 80.21 (3), A/C = 80.07 (3) and B/C = 0.66 (3) °. The quinoxaline ring system is planar with a maximum deviation of -0.013 (3) Å for atom N1.

In the crystal structure, intermolecular C-H···N interactions link the molecules into chains (Fig. 2), in which they may be effective in the stabilization of the structure. The π–π contact between the quinoxaline rings, Cg2—Cg3ⁱ [symmetry code: (i) x, y - 1, z, where Cg2 and Cg3 are centroids of the rings B (C13-C18) and C (N1/N2/C12/C13/C18/C19), respectively] may further stabilize the structure, with centroid-centroid distance of 3.654 (1) Å.

Related literature top

The title compound has potent selective herbicidal activity against annual and perennial grass weeds, see: Sakata et al. (1985). For bond-length data, see: Allen et al. (1987);

Experimental top

For the preparation of the title compound, thionyl chloride (3.7 ml, 50 mmol) was added in dropwise to (S)-2-(4-(6-chloroquinoxalin-2-yloxy)phenoxy)propanoate acid (3.72 g, 10 mmol) in an ice bath (263 K). After refluxing for 5 h, the mixture was cooled to room temperature, and excess thionyl chloride was removed by reduced pressure distillation. Then, the residue was dissolved in a solution of ethanol (4.9 ml, 80 mmol) and pyridine (2.5 ml, 30 mmol). The solid residue was extracted with hexane (40 ml) and hexane was distilled off. Crystals suitable for X-ray analysis were formed after 8 d in ethyl acetate by slow evaporation at room temperature.

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1985); cell refinement: CAD-4 Software (Enraf–Nonius, 1985); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. A partial packing diagram of the title compound. Hydrogen bonds are shown as dashed lines.

(S)-Ethyl 2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propanoate top

Crystal data top

C₁₉H₁₇ClN₂O₄	F(000) = 388
M_r = 372.80	D_x = 1.361 Mg m⁻³
Monoclinic, P2₁	Melting point: 350 K
Hall symbol: P 2yb	Mo Kα radiation, λ = 0.71073 Å
a = 9.970 (2) Å	Cell parameters from 25 reflections
b = 4.4760 (9) Å	θ = 9–12°
c = 20.450 (4) Å	µ = 0.24 mm⁻¹
β = 94.54 (3)°	T = 294 K
V = 909.7 (3) Å³	Needle, colorless
Z = 2	0.30 × 0.20 × 0.10 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	1254 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.052
Graphite monochromator	θ_max = 25.4°, θ_min = 2.0°
ω/2θ scans	h = −11→11
Absorption correction: ψ scan (North et al., 1968)	k = −5→0
T_min = 0.932, T_max = 0.977	l = −24→24
3762 measured reflections	3 standard reflections every 120 min
1898 independent reflections	intensity decay: 1%

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.050	H-atom parameters constrained
wR(F²) = 0.155	w = 1/[σ²(F_o²) + (0.085P)²] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max < 0.001
1898 reflections	Δρ_max = 0.17 e Å⁻³
235 parameters	Δρ_min = −0.20 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 932 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.02 (18)

Crystal data top

C₁₉H₁₇ClN₂O₄	V = 909.7 (3) Å³
M_r = 372.80	Z = 2
Monoclinic, P2₁	Mo Kα radiation
a = 9.970 (2) Å	µ = 0.24 mm⁻¹
b = 4.4760 (9) Å	T = 294 K
c = 20.450 (4) Å	0.30 × 0.20 × 0.10 mm
β = 94.54 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1254 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.052
T_min = 0.932, T_max = 0.977	3 standard reflections every 120 min
3762 measured reflections	intensity decay: 1%
1898 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.050	H-atom parameters constrained
wR(F²) = 0.155	Δρ_max = 0.17 e Å⁻³
S = 1.00	Δρ_min = −0.20 e Å⁻³
1898 reflections	Absolute structure: Flack (1983), 932 Friedel pairs
235 parameters	Absolute structure parameter: −0.02 (18)
1 restraint

Special details top

Experimental. 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.

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
Cl	0.50826 (14)	0.9066 (5)	0.08796 (7)	0.0921 (6)
O1	1.8615 (3)	0.4503 (12)	0.3878 (2)	0.0925 (14)
O2	1.7523 (4)	0.0871 (12)	0.3367 (2)	0.0956 (14)
O3	1.5198 (3)	0.2389 (10)	0.38949 (16)	0.0730 (11)
O4	1.2147 (3)	0.1148 (12)	0.15458 (16)	0.0838 (13)
N1	0.9132 (4)	0.2496 (12)	0.05649 (17)	0.0616 (11)
N2	1.0378 (4)	0.4196 (12)	0.18081 (17)	0.0563 (10)
C1	2.0926 (5)	0.474 (2)	0.4119 (4)	0.131 (3)
H1B	2.1793	0.4138	0.3993	0.196*
H1C	2.0803	0.3998	0.4551	0.196*
H1D	2.0871	0.6882	0.4120	0.196*
C2	1.9882 (5)	0.353 (2)	0.3656 (3)	0.095 (2)
H2B	1.9988	0.4282	0.3218	0.115*
H2C	1.9928	0.1370	0.3648	0.115*
C3	1.7536 (5)	0.3000 (15)	0.3698 (3)	0.0657 (15)
C4	1.6313 (4)	0.4380 (16)	0.3988 (2)	0.0710 (15)
H4A	1.6092	0.6308	0.3779	0.085*
C5	1.6551 (6)	0.476 (2)	0.4726 (3)	0.107 (3)
H5A	1.5771	0.5645	0.4893	0.161*
H5B	1.7316	0.6029	0.4824	0.161*
H5C	1.6716	0.2841	0.4927	0.161*
C6	1.4468 (4)	0.2317 (14)	0.3298 (2)	0.0582 (13)
C7	1.3386 (5)	0.0408 (14)	0.3263 (2)	0.0656 (14)
H7A	1.3203	−0.0682	0.3633	0.079*
C8	1.2570 (5)	0.0074 (15)	0.2696 (2)	0.0715 (17)
H8A	1.1837	−0.1217	0.2677	0.086*
C9	1.2861 (5)	0.1681 (15)	0.2160 (2)	0.0637 (15)
C10	1.3937 (5)	0.3564 (15)	0.2181 (3)	0.0720 (15)
H10A	1.4119	0.4639	0.1808	0.086*
C11	1.4758 (5)	0.3883 (16)	0.2752 (3)	0.0718 (15)
H11A	1.5500	0.5147	0.2765	0.086*
C12	1.0919 (5)	0.2395 (14)	0.1409 (2)	0.0612 (13)
C13	0.9127 (4)	0.5295 (12)	0.1580 (2)	0.0517 (12)
C14	0.8466 (5)	0.7268 (13)	0.1979 (2)	0.0586 (13)
H14A	0.8859	0.7811	0.2389	0.070*
C15	0.7228 (5)	0.8395 (14)	0.1757 (2)	0.0658 (15)
H15A	0.6783	0.9715	0.2017	0.079*
C16	0.6646 (5)	0.7562 (14)	0.1148 (2)	0.0626 (14)
C17	0.7261 (5)	0.5646 (14)	0.0749 (2)	0.0614 (14)
H17A	0.6852	0.5136	0.0340	0.074*
C18	0.8516 (4)	0.4457 (12)	0.0964 (2)	0.0509 (12)
C19	1.0293 (5)	0.1538 (15)	0.0790 (2)	0.0646 (15)
H19A	1.0746	0.0216	0.0534	0.078*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl	0.0714 (9)	0.1061 (14)	0.0958 (11)	0.0193 (10)	−0.0124 (7)	0.0154 (11)
O1	0.056 (2)	0.079 (3)	0.141 (3)	−0.003 (2)	0.003 (2)	−0.029 (3)
O2	0.092 (3)	0.083 (3)	0.111 (3)	0.010 (3)	0.002 (2)	−0.037 (3)
O3	0.063 (2)	0.087 (3)	0.067 (2)	−0.018 (2)	−0.0070 (16)	0.000 (2)
O4	0.065 (2)	0.115 (4)	0.070 (2)	0.028 (3)	−0.0046 (17)	−0.022 (2)
N1	0.061 (2)	0.071 (3)	0.051 (2)	−0.001 (3)	−0.0001 (18)	0.002 (2)
N2	0.054 (2)	0.066 (3)	0.049 (2)	0.001 (2)	−0.0021 (16)	−0.001 (2)
C1	0.062 (4)	0.123 (8)	0.205 (8)	0.012 (5)	−0.004 (4)	−0.024 (7)
C2	0.066 (3)	0.099 (5)	0.123 (5)	0.013 (4)	0.016 (3)	0.007 (5)
C3	0.061 (3)	0.067 (4)	0.068 (3)	0.001 (3)	−0.003 (2)	0.000 (3)
C4	0.055 (3)	0.067 (4)	0.089 (4)	−0.005 (3)	−0.004 (2)	−0.014 (3)
C5	0.078 (4)	0.156 (8)	0.087 (4)	−0.006 (5)	0.001 (3)	−0.055 (5)
C6	0.048 (2)	0.064 (3)	0.063 (3)	−0.002 (3)	0.004 (2)	−0.006 (3)
C7	0.058 (3)	0.074 (4)	0.064 (3)	−0.009 (3)	0.004 (2)	−0.001 (3)
C8	0.054 (3)	0.091 (5)	0.070 (3)	−0.010 (3)	0.009 (2)	−0.013 (3)
C9	0.051 (3)	0.077 (4)	0.062 (3)	0.014 (3)	−0.004 (2)	−0.016 (3)
C10	0.073 (3)	0.070 (4)	0.072 (3)	0.002 (3)	0.002 (3)	0.008 (3)
C11	0.061 (3)	0.074 (4)	0.080 (3)	−0.017 (3)	−0.002 (2)	0.011 (4)
C12	0.060 (3)	0.070 (4)	0.053 (3)	0.000 (3)	0.002 (2)	0.002 (3)
C13	0.052 (2)	0.056 (3)	0.047 (2)	−0.007 (2)	−0.0007 (19)	0.005 (2)
C14	0.061 (3)	0.057 (3)	0.056 (3)	−0.002 (3)	−0.001 (2)	0.004 (3)
C15	0.069 (3)	0.062 (4)	0.067 (3)	0.007 (3)	0.010 (2)	0.004 (3)
C16	0.055 (3)	0.066 (4)	0.065 (3)	−0.001 (3)	−0.002 (2)	0.015 (3)
C17	0.065 (3)	0.069 (4)	0.049 (2)	−0.006 (3)	−0.010 (2)	0.011 (3)
C18	0.056 (2)	0.051 (3)	0.045 (2)	−0.010 (3)	0.0043 (19)	0.003 (2)
C19	0.072 (3)	0.076 (4)	0.047 (2)	0.001 (3)	0.006 (2)	−0.010 (3)

Geometric parameters (Å, º) top

Cl—C16	1.746 (5)	C5—H5C	0.9600
O1—C2	1.443 (6)	C6—C11	1.370 (7)
O1—C3	1.298 (7)	C6—C7	1.373 (7)
O2—C3	1.168 (7)	C7—C8	1.372 (6)
O3—C4	1.426 (6)	C7—H7A	0.9300
O3—C6	1.371 (5)	C8—C9	1.361 (8)
O4—C9	1.414 (6)	C8—H8A	0.9300
O4—C12	1.355 (6)	C9—C10	1.363 (8)
N1—C18	1.375 (6)	C10—C11	1.379 (7)
N1—C19	1.285 (6)	C10—H10A	0.9300
N2—C12	1.294 (7)	C11—H11A	0.9300
N2—C13	1.386 (6)	C12—C19	1.420 (6)
C1—C2	1.455 (9)	C13—C14	1.401 (7)
C1—H1B	0.9600	C13—C18	1.407 (6)
C1—H1C	0.9600	C14—C15	1.376 (7)
C1—H1D	0.9600	C14—H14A	0.9300
C2—H2B	0.9700	C15—C16	1.383 (7)
C2—H2C	0.9700	C15—H15A	0.9300
C3—C4	1.528 (8)	C16—C17	1.362 (7)
C4—C5	1.519 (7)	C17—C18	1.398 (6)
C4—H4A	0.9800	C17—H17A	0.9300
C5—H5A	0.9600	C19—H19A	0.9300
C5—H5B	0.9600

C3—O1—C2	118.8 (5)	C6—C7—H7A	119.2
C6—O3—C4	119.1 (4)	C9—C8—C7	118.3 (5)
C12—O4—C9	119.8 (4)	C9—C8—H8A	120.9
C19—N1—C18	115.6 (4)	C7—C8—H8A	120.9
C12—N2—C13	114.7 (4)	C8—C9—C10	121.3 (5)
C2—C1—H1B	109.5	C8—C9—O4	120.1 (5)
C2—C1—H1C	109.5	C10—C9—O4	118.1 (5)
C2—C1—H1D	109.5	C9—C10—C11	120.2 (5)
H1B—C1—H1C	109.5	C9—C10—H10A	119.9
H1B—C1—H1D	109.5	C11—C10—H10A	119.9
H1C—C1—H1D	109.5	C6—C11—C10	119.2 (5)
O1—C2—C1	106.4 (6)	C6—C11—H11A	120.4
O1—C2—H2B	110.4	C10—C11—H11A	120.4
C1—C2—H2B	110.4	N2—C12—O4	122.8 (4)
O1—C2—H2C	110.4	N2—C12—C19	123.7 (5)
C1—C2—H2C	110.4	O4—C12—C19	113.5 (5)
H2B—C2—H2C	108.6	N2—C13—C14	118.7 (4)
O2—C3—O1	124.0 (6)	N2—C13—C18	121.4 (4)
O2—C3—C4	125.6 (6)	C14—C13—C18	119.9 (4)
O1—C3—C4	110.4 (5)	C15—C14—C13	119.4 (4)
O3—C4—C5	105.1 (5)	C15—C14—H14A	120.3
O3—C4—C3	109.5 (5)	C13—C14—H14A	120.3
C5—C4—C3	111.4 (4)	C14—C15—C16	119.9 (5)
O3—C4—H4A	110.3	C14—C15—H15A	120.1
C5—C4—H4A	110.3	C16—C15—H15A	120.1
C3—C4—H4A	110.3	C17—C16—C15	122.2 (5)
C4—C5—H5A	109.5	C17—C16—Cl	119.2 (4)
C4—C5—H5B	109.5	C15—C16—Cl	118.6 (5)
H5A—C5—H5B	109.5	C16—C17—C18	119.1 (4)
C4—C5—H5C	109.5	C16—C17—H17A	120.4
H5A—C5—H5C	109.5	C18—C17—H17A	120.4
H5B—C5—H5C	109.5	N1—C18—C17	119.2 (4)
C11—C6—O3	125.7 (5)	N1—C18—C13	121.3 (4)
C11—C6—C7	119.5 (5)	C17—C18—C13	119.5 (5)
O3—C6—C7	114.9 (5)	N1—C19—C12	123.3 (5)
C8—C7—C6	121.5 (5)	N1—C19—H19A	118.3
C8—C7—H7A	119.2	C12—C19—H19A	118.3

C3—O1—C2—C1	−157.4 (6)	C13—N2—C12—C19	−1.0 (8)
C2—O1—C3—O2	0.7 (9)	C9—O4—C12—N2	3.3 (9)
C2—O1—C3—C4	179.7 (5)	C9—O4—C12—C19	−176.8 (5)
C6—O3—C4—C5	159.6 (5)	C12—N2—C13—C14	−179.9 (5)
C6—O3—C4—C3	−80.7 (6)	C12—N2—C13—C18	0.4 (7)
O2—C3—C4—O3	10.5 (8)	N2—C13—C14—C15	179.5 (5)
O1—C3—C4—O3	−168.5 (4)	C18—C13—C14—C15	−0.8 (7)
O2—C3—C4—C5	126.3 (7)	C13—C14—C15—C16	0.4 (8)
O1—C3—C4—C5	−52.7 (8)	C14—C15—C16—C17	−0.3 (8)
C4—O3—C6—C11	4.3 (8)	C14—C15—C16—Cl	−179.3 (4)
C4—O3—C6—C7	−177.8 (5)	C15—C16—C17—C18	0.6 (8)
C11—C6—C7—C8	−1.3 (9)	Cl—C16—C17—C18	179.7 (4)
O3—C6—C7—C8	−179.3 (5)	C19—N1—C18—C17	178.8 (5)
C6—C7—C8—C9	0.3 (8)	C19—N1—C18—C13	−0.9 (7)
C7—C8—C9—C10	0.4 (8)	C16—C17—C18—N1	179.3 (5)
C7—C8—C9—O4	172.5 (5)	C16—C17—C18—C13	−1.0 (7)
C12—O4—C9—C8	81.4 (7)	N2—C13—C18—N1	0.5 (7)
C12—O4—C9—C10	−106.3 (6)	C14—C13—C18—N1	−179.2 (5)
C8—C9—C10—C11	−0.1 (9)	N2—C13—C18—C17	−179.2 (5)
O4—C9—C10—C11	−172.4 (6)	C14—C13—C18—C17	1.1 (7)
O3—C6—C11—C10	179.3 (5)	C18—N1—C19—C12	0.4 (8)
C7—C6—C11—C10	1.5 (9)	N2—C12—C19—N1	0.6 (9)
C9—C10—C11—C6	−0.9 (9)	O4—C12—C19—N1	−179.2 (5)
C13—N2—C12—O4	178.9 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C19—H19A···N1ⁱ	0.93	2.57	3.396 (7)	149

Symmetry code: (i) −x+2, y−1/2, −z.

Experimental details

Crystal data
Chemical formula	C₁₉H₁₇ClN₂O₄
M_r	372.80
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	294
a, b, c (Å)	9.970 (2), 4.4760 (9), 20.450 (4)
β (°)	94.54 (3)
V (Å³)	909.7 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.24
Crystal size (mm)	0.30 × 0.20 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.932, 0.977
No. of measured, independent and observed [I > 2σ(I)] reflections	3762, 1898, 1254
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.604

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.050, 0.155, 1.00
No. of reflections	1898
No. of parameters	235
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.20
Absolute structure	Flack (1983), 932 Friedel pairs
Absolute structure parameter	−0.02 (18)

Computer programs: CAD-4 Software (Enraf–Nonius, 1985), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C19—H19A···N1ⁱ	0.93	2.57	3.396 (7)	149

Symmetry code: (i) −x+2, y−1/2, −z.

Acknowledgements

The authors thank the Center of Testing and Analysis, Nanjing University for support.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Enraf–Nonius (1985). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar