PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2009 September 1; 65(Pt 9): o2082.
Published online 2009 August 8. doi:  10.1107/S1600536809030074
PMCID: PMC2969970

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

Abstract

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 [triangle]). For bond-length data, see: Allen et al. (1987 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o2082-scheme1.jpg

Experimental

Crystal data

  • C19H17ClN2O4
  • M r = 372.80
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2082-efi1.jpg
  • 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 [triangle]) 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[F 2 > 2σ(F 2)] = 0.050
  • wR(F 2) = 0.155
  • S = 1.00
  • 1898 reflections
  • 235 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.17 e Å−3
  • Δρmin = −0.20 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 932 Friedel pairs
  • Flack parameter: −0.02 (18)

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

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

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

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

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

Acknowledgments

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

supplementary crystallographic information

Comment

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.

Experimental

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.

Refinement

H atoms were positioned geometrically with C-H = 0.93, 0.98, 0.97 and 0.96 Å, for aromatic, methine, methylene and methyl H atoms, respectively, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and x = 1.2 for aromatic H atoms.

Figures

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.

Crystal data

C19H17ClN2O4F(000) = 388
Mr = 372.80Dx = 1.361 Mg m3
Monoclinic, P21Melting point: 350 K
Hall symbol: P 2ybMo Kα radiation, λ = 0.71073 Å
a = 9.970 (2) ÅCell parameters from 25 reflections
b = 4.4760 (9) Åθ = 9–12°
c = 20.450 (4) ŵ = 0.24 mm1
β = 94.54 (3)°T = 294 K
V = 909.7 (3) Å3Needle, colorless
Z = 20.30 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer1254 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.052
graphiteθmax = 25.4°, θmin = 2.0°
ω/2θ scansh = −11→11
Absorption correction: ψ scan (North et al., 1968)k = −5→0
Tmin = 0.932, Tmax = 0.977l = −24→24
3762 measured reflections3 standard reflections every 120 min
1898 independent reflections intensity decay: 1%

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.155w = 1/[σ2(Fo2) + (0.085P)2] where P = (Fo2 + 2Fc2)/3
S = 1.00(Δ/σ)max < 0.001
1898 reflectionsΔρmax = 0.17 e Å3
235 parametersΔρmin = −0.19 e Å3
1 restraintAbsolute structure: Flack (1983), 932 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: −0.02 (18)

Special details

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)

xyzUiso*/Ueq
Cl0.50826 (14)0.9066 (5)0.08796 (7)0.0921 (6)
O11.8615 (3)0.4503 (12)0.3878 (2)0.0925 (14)
O21.7523 (4)0.0871 (12)0.3367 (2)0.0956 (14)
O31.5198 (3)0.2389 (10)0.38949 (16)0.0730 (11)
O41.2147 (3)0.1148 (12)0.15458 (16)0.0838 (13)
N10.9132 (4)0.2496 (12)0.05649 (17)0.0616 (11)
N21.0378 (4)0.4196 (12)0.18081 (17)0.0563 (10)
C12.0926 (5)0.474 (2)0.4119 (4)0.131 (3)
H1B2.17930.41380.39930.196*
H1C2.08030.39980.45510.196*
H1D2.08710.68820.41200.196*
C21.9882 (5)0.353 (2)0.3656 (3)0.095 (2)
H2B1.99880.42820.32180.115*
H2C1.99280.13700.36480.115*
C31.7536 (5)0.3000 (15)0.3698 (3)0.0657 (15)
C41.6313 (4)0.4380 (16)0.3988 (2)0.0710 (15)
H4A1.60920.63080.37790.085*
C51.6551 (6)0.476 (2)0.4726 (3)0.107 (3)
H5A1.57710.56450.48930.161*
H5B1.73160.60290.48240.161*
H5C1.67160.28410.49270.161*
C61.4468 (4)0.2317 (14)0.3298 (2)0.0582 (13)
C71.3386 (5)0.0408 (14)0.3263 (2)0.0656 (14)
H7A1.3203−0.06820.36330.079*
C81.2570 (5)0.0074 (15)0.2696 (2)0.0715 (17)
H8A1.1837−0.12170.26770.086*
C91.2861 (5)0.1681 (15)0.2160 (2)0.0637 (15)
C101.3937 (5)0.3564 (15)0.2181 (3)0.0720 (15)
H10A1.41190.46390.18080.086*
C111.4758 (5)0.3883 (16)0.2752 (3)0.0718 (15)
H11A1.55000.51470.27650.086*
C121.0919 (5)0.2395 (14)0.1409 (2)0.0612 (13)
C130.9127 (4)0.5295 (12)0.1580 (2)0.0517 (12)
C140.8466 (5)0.7268 (13)0.1979 (2)0.0586 (13)
H14A0.88590.78110.23890.070*
C150.7228 (5)0.8395 (14)0.1757 (2)0.0658 (15)
H15A0.67830.97150.20170.079*
C160.6646 (5)0.7562 (14)0.1148 (2)0.0626 (14)
C170.7261 (5)0.5646 (14)0.0749 (2)0.0614 (14)
H17A0.68520.51360.03400.074*
C180.8516 (4)0.4457 (12)0.0964 (2)0.0509 (12)
C191.0293 (5)0.1538 (15)0.0790 (2)0.0646 (15)
H19A1.07460.02160.05340.078*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Cl0.0714 (9)0.1061 (14)0.0958 (11)0.0193 (10)−0.0124 (7)0.0154 (11)
O10.056 (2)0.079 (3)0.141 (3)−0.003 (2)0.003 (2)−0.029 (3)
O20.092 (3)0.083 (3)0.111 (3)0.010 (3)0.002 (2)−0.037 (3)
O30.063 (2)0.087 (3)0.067 (2)−0.018 (2)−0.0070 (16)0.000 (2)
O40.065 (2)0.115 (4)0.070 (2)0.028 (3)−0.0046 (17)−0.022 (2)
N10.061 (2)0.071 (3)0.051 (2)−0.001 (3)−0.0001 (18)0.002 (2)
N20.054 (2)0.066 (3)0.049 (2)0.001 (2)−0.0021 (16)−0.001 (2)
C10.062 (4)0.123 (8)0.205 (8)0.012 (5)−0.004 (4)−0.024 (7)
C20.066 (3)0.099 (5)0.123 (5)0.013 (4)0.016 (3)0.007 (5)
C30.061 (3)0.067 (4)0.068 (3)0.001 (3)−0.003 (2)0.000 (3)
C40.055 (3)0.067 (4)0.089 (4)−0.005 (3)−0.004 (2)−0.014 (3)
C50.078 (4)0.156 (8)0.087 (4)−0.006 (5)0.001 (3)−0.055 (5)
C60.048 (2)0.064 (3)0.063 (3)−0.002 (3)0.004 (2)−0.006 (3)
C70.058 (3)0.074 (4)0.064 (3)−0.009 (3)0.004 (2)−0.001 (3)
C80.054 (3)0.091 (5)0.070 (3)−0.010 (3)0.009 (2)−0.013 (3)
C90.051 (3)0.077 (4)0.062 (3)0.014 (3)−0.004 (2)−0.016 (3)
C100.073 (3)0.070 (4)0.072 (3)0.002 (3)0.002 (3)0.008 (3)
C110.061 (3)0.074 (4)0.080 (3)−0.017 (3)−0.002 (2)0.011 (4)
C120.060 (3)0.070 (4)0.053 (3)0.000 (3)0.002 (2)0.002 (3)
C130.052 (2)0.056 (3)0.047 (2)−0.007 (2)−0.0007 (19)0.005 (2)
C140.061 (3)0.057 (3)0.056 (3)−0.002 (3)−0.001 (2)0.004 (3)
C150.069 (3)0.062 (4)0.067 (3)0.007 (3)0.010 (2)0.004 (3)
C160.055 (3)0.066 (4)0.065 (3)−0.001 (3)−0.002 (2)0.015 (3)
C170.065 (3)0.069 (4)0.049 (2)−0.006 (3)−0.010 (2)0.011 (3)
C180.056 (2)0.051 (3)0.045 (2)−0.010 (3)0.0043 (19)0.003 (2)
C190.072 (3)0.076 (4)0.047 (2)0.001 (3)0.006 (2)−0.010 (3)

Geometric parameters (Å, °)

Cl—C161.746 (5)C5—H5C0.9600
O1—C21.443 (6)C6—C111.370 (7)
O1—C31.298 (7)C6—C71.373 (7)
O2—C31.168 (7)C7—C81.372 (6)
O3—C41.426 (6)C7—H7A0.9300
O3—C61.371 (5)C8—C91.361 (8)
O4—C91.414 (6)C8—H8A0.9300
O4—C121.355 (6)C9—C101.363 (8)
N1—C181.375 (6)C10—C111.379 (7)
N1—C191.285 (6)C10—H10A0.9300
N2—C121.294 (7)C11—H11A0.9300
N2—C131.386 (6)C12—C191.420 (6)
C1—C21.455 (9)C13—C141.401 (7)
C1—H1B0.9600C13—C181.407 (6)
C1—H1C0.9600C14—C151.376 (7)
C1—H1D0.9600C14—H14A0.9300
C2—H2B0.9700C15—C161.383 (7)
C2—H2C0.9700C15—H15A0.9300
C3—C41.528 (8)C16—C171.362 (7)
C4—C51.519 (7)C17—C181.398 (6)
C4—H4A0.9800C17—H17A0.9300
C5—H5A0.9600C19—H19A0.9300
C5—H5B0.9600
C3—O1—C2118.8 (5)C6—C7—H7A119.2
C6—O3—C4119.1 (4)C9—C8—C7118.3 (5)
C12—O4—C9119.8 (4)C9—C8—H8A120.9
C19—N1—C18115.6 (4)C7—C8—H8A120.9
C12—N2—C13114.7 (4)C8—C9—C10121.3 (5)
C2—C1—H1B109.5C8—C9—O4120.1 (5)
C2—C1—H1C109.5C10—C9—O4118.1 (5)
C2—C1—H1D109.5C9—C10—C11120.2 (5)
H1B—C1—H1C109.5C9—C10—H10A119.9
H1B—C1—H1D109.5C11—C10—H10A119.9
H1C—C1—H1D109.5C6—C11—C10119.2 (5)
O1—C2—C1106.4 (6)C6—C11—H11A120.4
O1—C2—H2B110.4C10—C11—H11A120.4
C1—C2—H2B110.4N2—C12—O4122.8 (4)
O1—C2—H2C110.4N2—C12—C19123.7 (5)
C1—C2—H2C110.4O4—C12—C19113.5 (5)
H2B—C2—H2C108.6N2—C13—C14118.7 (4)
O2—C3—O1124.0 (6)N2—C13—C18121.4 (4)
O2—C3—C4125.6 (6)C14—C13—C18119.9 (4)
O1—C3—C4110.4 (5)C15—C14—C13119.4 (4)
O3—C4—C5105.1 (5)C15—C14—H14A120.3
O3—C4—C3109.5 (5)C13—C14—H14A120.3
C5—C4—C3111.4 (4)C14—C15—C16119.9 (5)
O3—C4—H4A110.3C14—C15—H15A120.1
C5—C4—H4A110.3C16—C15—H15A120.1
C3—C4—H4A110.3C17—C16—C15122.2 (5)
C4—C5—H5A109.5C17—C16—Cl119.2 (4)
C4—C5—H5B109.5C15—C16—Cl118.6 (5)
H5A—C5—H5B109.5C16—C17—C18119.1 (4)
C4—C5—H5C109.5C16—C17—H17A120.4
H5A—C5—H5C109.5C18—C17—H17A120.4
H5B—C5—H5C109.5N1—C18—C17119.2 (4)
C11—C6—O3125.7 (5)N1—C18—C13121.3 (4)
C11—C6—C7119.5 (5)C17—C18—C13119.5 (5)
O3—C6—C7114.9 (5)N1—C19—C12123.3 (5)
C8—C7—C6121.5 (5)N1—C19—H19A118.3
C8—C7—H7A119.2C12—C19—H19A118.3
C3—O1—C2—C1−157.4 (6)C13—N2—C12—C19−1.0 (8)
C2—O1—C3—O20.7 (9)C9—O4—C12—N23.3 (9)
C2—O1—C3—C4179.7 (5)C9—O4—C12—C19−176.8 (5)
C6—O3—C4—C5159.6 (5)C12—N2—C13—C14−179.9 (5)
C6—O3—C4—C3−80.7 (6)C12—N2—C13—C180.4 (7)
O2—C3—C4—O310.5 (8)N2—C13—C14—C15179.5 (5)
O1—C3—C4—O3−168.5 (4)C18—C13—C14—C15−0.8 (7)
O2—C3—C4—C5126.3 (7)C13—C14—C15—C160.4 (8)
O1—C3—C4—C5−52.7 (8)C14—C15—C16—C17−0.3 (8)
C4—O3—C6—C114.3 (8)C14—C15—C16—Cl−179.3 (4)
C4—O3—C6—C7−177.8 (5)C15—C16—C17—C180.6 (8)
C11—C6—C7—C8−1.3 (9)Cl—C16—C17—C18179.7 (4)
O3—C6—C7—C8−179.3 (5)C19—N1—C18—C17178.8 (5)
C6—C7—C8—C90.3 (8)C19—N1—C18—C13−0.9 (7)
C7—C8—C9—C100.4 (8)C16—C17—C18—N1179.3 (5)
C7—C8—C9—O4172.5 (5)C16—C17—C18—C13−1.0 (7)
C12—O4—C9—C881.4 (7)N2—C13—C18—N10.5 (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—C171.1 (7)
O3—C6—C11—C10179.3 (5)C18—N1—C19—C120.4 (8)
C7—C6—C11—C101.5 (9)N2—C12—C19—N10.6 (9)
C9—C10—C11—C6−0.9 (9)O4—C12—C19—N1−179.2 (5)
C13—N2—C12—O4178.9 (5)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C19—H19A···N1i0.932.573.396 (7)149

Symmetry codes: (i) −x+2, y−1/2, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HK2712).

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.
  • Enraf–Nonius (1985). CAD-4 Software Enraf–Nonius, Delft, The Netherlands.
  • Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  • Harms, K. & Wocadlo, S. (1995). XCAD4 University of Marburg, Germany.
  • North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.
  • Sakata, G., Makino, K., Morimoto, K., Ikai, T. & Hasebe, S. (1985). Nippon Noyaku Gakkaishi, 10, 69–73.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography