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Acta Crystallogr Sect E Struct Rep Online. 2010 February 1; 66(Pt 2): o396.
Published online 2010 January 20. doi:  10.1107/S1600536810001583
PMCID: PMC2979917

Ethyl (E)-2-methoxy­imino-2-(4-nitro­benzo­yl)acetate

Abstract

The title mol­ecule, C12H12N2O6, features an E conformation about the oxime group. The methoxy­imino and ester residues are effectively coplanar with each other (r.m.s. deviation for the nine non-H atoms = 0.127 Å) and almost orthogonal [with dihedral angles of 99.44 (13) and −77.85 (13)°, respectively] to the carbonyl and nitro­phenyl groups which lie to either side of this central plane. The crystal structure is consolidated by C—H(...)O contacts.

Related literature

For background to the synthesis of chiral hydroxy­amino­acids and hydroxy­amino­alcohols, see: Corrêa & Moran (1999 [triangle]); Kreutz et al. (1997 [triangle], 2000 [triangle]). For related structures, see: Caracelli et al. (2010 [triangle]); Forsyth et al. (2006 [triangle]); Ramos Silva et al. (2004 [triangle]). For the synthesis of the title compound, see: Buehler (1967 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-0o396-scheme1.jpg

Experimental

Crystal data

  • C12H12N2O6
  • M r = 280.24
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o396-efi1.jpg
  • a = 7.5197 (1) Å
  • b = 7.5793 (1) Å
  • c = 12.3338 (2) Å
  • α = 83.264 (1)°
  • β = 73.731 (1)°
  • γ = 68.939 (1)°
  • V = 629.62 (2) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.12 mm−1
  • T = 100 K
  • 0.35 × 0.25 × 0.08 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.933, T max = 1.000
  • 9325 measured reflections
  • 2614 independent reflections
  • 2310 reflections with I > 2σ(I)
  • R int = 0.018

Refinement

  • R[F 2 > 2σ(F 2)] = 0.031
  • wR(F 2) = 0.088
  • S = 1.05
  • 2614 reflections
  • 183 parameters
  • H-atom parameters constrained
  • Δρmax = 0.28 e Å−3
  • Δρmin = −0.24 e Å−3

Data collection: APEX2 (Bruker, 2007 [triangle]); cell refinement: SAINT (Bruker, 2007 [triangle]); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]) and DIAMOND (Brandenburg, 2006 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]), PARST (Nardelli, 1995 [triangle]) and publCIF (Westrip, 2010 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810001583/su2157sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810001583/su2157Isup2.hkl

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

Acknowledgments

We thank FAPESP, CNPq and CAPES for financial support.

supplementary crystallographic information

Comment

In connection with studies involving the synthesis of chiral hydroxyaminoacids and hydroxyaminoalcohols, whereby α-ketomethoxyimino compounds are reduced by sodium borohydride (Corrêa & Moran, 1999) and enantioselectively bio-reduced by whole cells of yeast (Kreutz et al., 1997; Kreutz et al., 2000), the title compound was prepared as an intermediary.

The molecular structure of the title compound is illustrated in Fig. 1, and the geometrical parameters are given in the Supplementary information and the archived CIF. The conformation about the oxime bond [N2═C8 = 1.2790 (14) Å] is E. The methoxyimino moiety is effectively co-planar with the ester group, as seen in the sequence of O4-N2-C8-C9, N2-C8-C9-O5 and C8-C9-O6-C10 torsion angles of 177.54 (8), 6.76 (16) and 178.40 (9) °, respectively. While atom C7 lies in the mean plane of the ester group [O4-N2-C8-C7 = 2.17 (14) °], the carbonyl and nitrophenyl groups occupy positions almost orthogonal to the remaining atoms, as seen in the values of the N2-C8-C7-O3 and N2-C8-C7-C4 torsion angles of 99.44 (13) and -77.85 (13) °, respectively. The nitro group and the benzene ring to which it is attached are slightly twisted with respect to one another, with a dihedral angle of 8.54 (8)°. Globally, when viewed down the C7–C8 bond, the carbonyl-O3 atom lies to one side of the central plane and the nitrophenyl group to the other.

The crystal packing is dominated by C–H(aromatic)···O interactions involving the nitro-O2, carbonyl-O3 and oxime-O4 atoms to form layers in the ab plane (Table 1 and Fig. 2). These layers stack along [001] with interdigitation of the ethyl ester groups (Fig. 3), and C–H···O interactions involving the ester carbonyl-O5 atom.

The basic C(═O)C(═NOH)C(═O)OC framework in the title compound is comparatively rare with only three other structures reported, namely the recently described Z-isomer of the title compound (Caracelli et al., 2010), 2-(hydroxyimino)-3-oxo-3-phenylpropionate, where E-conformations are found for each of the independent molecules (Ramos Silva et al., 2004), and benzyl 2-(hydroxyimino)acetoacetate, for which a Z conformation is found (Forsyth et al., 2006).

Experimental

The title compound was prepared following a modified literature method (Buehler, 1967). Silver oxide (1.3 mmol) was slowly added with stirring to a solution of a mixture of ethyl (E)- and (Z)-2-hydroximino-3-(4-nitrophenyl)-3-oxopropanoate (2.25 mmol) and methyl iodide (5.6 mmol) in CH2Cl2 (30 ml), and cooled in a ice-water bath. The temperature was then raised to 301 K and the stirring maintained for 1 h. The precipitate formed was filtered off and washed with CH2Cl2. The solvent was evaporated to afford yellow crystals of a mixture of E:Z (90:10) isomers in 86% yield. They were separated by TLC chromatography on silica gel with 5% ethyl acetate/hexane. The principal fraction was shown by crystallographic analysis to be the E isomer; m.p. 367.6–368.0 K.

Refinement

The H atoms were placed geometrically (C–H = 0.93–0.97 Å) and refined in the riding model approximation with Uiso(H) = 1.2Ueq(C-aromatic) and 1.5Ueq(C-methyl).

Figures

Fig. 1.
Molecular structure of the title compound, showing the atom labelling scheme and displacement ellipsoids at the 50% probability level (arbitrary spheres for the H atoms).
Fig. 2.
A view of the layer structure in the title compound, sustained by C–H···O contacts [the C–H···O contacts are shown as brown dashed lines; colour code: O, red; N, blue; C, grey; H, green]. ...
Fig. 3.
A view along the b axis of the crystal packing of the title compound, highlighting the interdigitation of the ester groups [the C–H···O contacts are shown as brown dashed lines; colour code: O, red; N, blue; C, grey; H, ...

Crystal data

C12H12N2O6Z = 2
Mr = 280.24F(000) = 292
Triclinic, P1Dx = 1.478 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.5197 (1) ÅCell parameters from 5430 reflections
b = 7.5793 (1) Åθ = 26.6–2.9°
c = 12.3338 (2) ŵ = 0.12 mm1
α = 83.264 (1)°T = 100 K
β = 73.731 (1)°Block, pale-yellow
γ = 68.939 (1)°0.35 × 0.25 × 0.08 mm
V = 629.62 (2) Å3

Data collection

Bruker APEXII CCD diffractometer2614 independent reflections
Radiation source: fine-focus sealed tube2310 reflections with I > 2σ(I)
graphiteRint = 0.018
[var phi] and ω scansθmax = 26.6°, θmin = 1.7°
Absorption correction: multi scan (SADABS; Sheldrick, 1996)h = −9→9
Tmin = 0.933, Tmax = 1.000k = −9→9
9325 measured reflectionsl = −15→15

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.031Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.088H-atom parameters constrained
S = 1.05w = 1/[σ2(Fo2) + (0.0456P)2 + 0.1834P] where P = (Fo2 + 2Fc2)/3
2614 reflections(Δ/σ)max = 0.001
183 parametersΔρmax = 0.28 e Å3
0 restraintsΔρmin = −0.24 e Å3

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
C10.95878 (16)0.26376 (14)0.48218 (9)0.0180 (2)
C20.77279 (16)0.24949 (15)0.51100 (9)0.0190 (2)
H20.72410.20000.58100.023*
C30.66149 (16)0.31060 (15)0.43316 (9)0.0185 (2)
H30.53700.30030.44980.022*
C40.73587 (16)0.38808 (14)0.32919 (9)0.0174 (2)
C50.92289 (16)0.40168 (15)0.30321 (9)0.0195 (2)
H50.97110.45390.23410.023*
C61.03760 (16)0.33776 (15)0.37975 (9)0.0195 (2)
H61.16360.34440.36280.023*
C70.60888 (16)0.45924 (14)0.24893 (9)0.0173 (2)
C80.67583 (15)0.57310 (15)0.14594 (9)0.0175 (2)
C90.75507 (16)0.49578 (15)0.02915 (9)0.0192 (2)
C100.81887 (17)0.23916 (16)−0.08355 (9)0.0209 (2)
H10B0.95880.2169−0.11330.025*
H10A0.74940.3237−0.13530.025*
C110.78050 (19)0.05568 (16)−0.07074 (10)0.0251 (3)
H11B0.8255−0.0029−0.14300.038*
H11C0.64160.0794−0.04160.038*
H11A0.8499−0.0268−0.01940.038*
C120.55476 (19)1.00856 (16)0.25880 (10)0.0243 (3)
H12C0.47591.07820.20840.036*
H12A0.68271.02090.23360.036*
H12B0.49201.05750.33360.036*
N20.65628 (13)0.74693 (13)0.15091 (8)0.0189 (2)
N11.07936 (14)0.19686 (13)0.56457 (8)0.0204 (2)
O60.74864 (12)0.32311 (11)0.02858 (6)0.02006 (19)
O50.81359 (14)0.58238 (12)−0.05260 (7)0.0283 (2)
O30.45219 (12)0.43609 (11)0.26469 (7)0.02198 (19)
O40.57531 (12)0.81146 (11)0.26006 (6)0.0221 (2)
O11.00183 (13)0.15085 (13)0.65930 (7)0.0300 (2)
O21.25168 (13)0.18865 (13)0.53367 (7)0.0285 (2)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0223 (6)0.0154 (5)0.0157 (5)−0.0056 (4)−0.0047 (4)−0.0012 (4)
C20.0233 (6)0.0175 (5)0.0144 (5)−0.0084 (4)−0.0006 (4)0.0004 (4)
C30.0184 (5)0.0185 (5)0.0182 (5)−0.0086 (4)−0.0006 (4)−0.0011 (4)
C40.0208 (5)0.0153 (5)0.0154 (5)−0.0070 (4)−0.0021 (4)−0.0012 (4)
C50.0215 (5)0.0202 (5)0.0156 (5)−0.0092 (4)−0.0014 (4)0.0021 (4)
C60.0180 (5)0.0209 (5)0.0194 (5)−0.0087 (4)−0.0020 (4)0.0001 (4)
C70.0196 (5)0.0155 (5)0.0154 (5)−0.0069 (4)−0.0005 (4)−0.0020 (4)
C80.0168 (5)0.0200 (5)0.0168 (5)−0.0082 (4)−0.0042 (4)0.0016 (4)
C90.0192 (5)0.0209 (5)0.0182 (5)−0.0079 (4)−0.0048 (4)0.0009 (4)
C100.0250 (6)0.0227 (5)0.0151 (5)−0.0090 (4)−0.0040 (4)−0.0010 (4)
C110.0329 (7)0.0234 (6)0.0217 (6)−0.0122 (5)−0.0080 (5)−0.0004 (5)
C120.0306 (6)0.0174 (5)0.0252 (6)−0.0089 (5)−0.0062 (5)−0.0017 (4)
N20.0200 (5)0.0212 (5)0.0156 (5)−0.0081 (4)−0.0036 (4)−0.0003 (4)
N10.0239 (5)0.0198 (5)0.0178 (5)−0.0080 (4)−0.0050 (4)−0.0001 (4)
O60.0259 (4)0.0197 (4)0.0152 (4)−0.0102 (3)−0.0029 (3)−0.0004 (3)
O50.0416 (5)0.0267 (4)0.0174 (4)−0.0187 (4)−0.0005 (4)0.0013 (3)
O30.0217 (4)0.0246 (4)0.0219 (4)−0.0121 (3)−0.0051 (3)0.0028 (3)
O40.0302 (4)0.0188 (4)0.0166 (4)−0.0104 (3)−0.0016 (3)−0.0017 (3)
O10.0309 (5)0.0414 (5)0.0160 (4)−0.0132 (4)−0.0049 (4)0.0057 (4)
O20.0245 (4)0.0382 (5)0.0269 (5)−0.0153 (4)−0.0094 (4)0.0058 (4)

Geometric parameters (Å, °)

C1—C61.3839 (15)C9—O51.2020 (14)
C1—C21.3839 (16)C9—O61.3278 (13)
C1—N11.4753 (14)C10—O61.4670 (13)
C2—C31.3798 (16)C10—C111.5011 (16)
C2—H20.9300C10—H10B0.9700
C3—C41.4000 (15)C10—H10A0.9700
C3—H30.9300C11—H11B0.9600
C4—C51.3910 (16)C11—H11C0.9600
C4—C71.4889 (15)C11—H11A0.9600
C5—C61.3851 (16)C12—O41.4442 (13)
C5—H50.9300C12—H12C0.9600
C6—H60.9300C12—H12A0.9600
C7—O31.2121 (14)C12—H12B0.9600
C7—C81.5194 (14)N2—O41.3797 (12)
C8—N21.2790 (14)N1—O11.2229 (12)
C8—C91.4965 (15)N1—O21.2244 (13)
C6—C1—C2123.25 (10)O6—C9—C8111.19 (9)
C6—C1—N1118.25 (10)O6—C10—C11107.57 (9)
C2—C1—N1118.51 (9)O6—C10—H10B110.2
C3—C2—C1118.23 (10)C11—C10—H10B110.2
C3—C2—H2120.9O6—C10—H10A110.2
C1—C2—H2120.9C11—C10—H10A110.2
C2—C3—C4120.00 (10)H10B—C10—H10A108.5
C2—C3—H3120.0C10—C11—H11B109.5
C4—C3—H3120.0C10—C11—H11C109.5
C5—C4—C3120.30 (10)H11B—C11—H11C109.5
C5—C4—C7121.09 (10)C10—C11—H11A109.5
C3—C4—C7118.59 (10)H11B—C11—H11A109.5
C6—C5—C4120.29 (10)H11C—C11—H11A109.5
C6—C5—H5119.9O4—C12—H12C109.5
C4—C5—H5119.9O4—C12—H12A109.5
C1—C6—C5117.91 (10)H12C—C12—H12A109.5
C1—C6—H6121.0O4—C12—H12B109.5
C5—C6—H6121.0H12C—C12—H12B109.5
O3—C7—C4122.79 (10)H12A—C12—H12B109.5
O3—C7—C8119.12 (10)C8—N2—O4111.55 (9)
C4—C7—C8118.03 (9)O1—N1—O2123.89 (10)
N2—C8—C9114.45 (9)O1—N1—C1118.03 (9)
N2—C8—C7122.66 (9)O2—N1—C1118.08 (9)
C9—C8—C7122.72 (9)C9—O6—C10114.57 (8)
O5—C9—O6125.40 (10)N2—O4—C12108.40 (8)
O5—C9—C8123.40 (10)
C6—C1—C2—C30.61 (16)O3—C7—C8—C9−75.55 (14)
N1—C1—C2—C3−179.38 (9)C4—C7—C8—C9107.17 (12)
C1—C2—C3—C4−1.27 (15)N2—C8—C9—O56.76 (16)
C2—C3—C4—C50.82 (16)C7—C8—C9—O5−177.87 (11)
C2—C3—C4—C7−177.73 (9)N2—C8—C9—O6−172.26 (9)
C3—C4—C5—C60.35 (16)C7—C8—C9—O63.10 (14)
C7—C4—C5—C6178.85 (10)C9—C8—N2—O4177.54 (8)
C2—C1—C6—C50.52 (16)C7—C8—N2—O42.17 (14)
N1—C1—C6—C5−179.49 (9)C6—C1—N1—O1172.19 (10)
C4—C5—C6—C1−0.99 (16)C2—C1—N1—O1−7.82 (14)
C5—C4—C7—O3173.89 (10)C6—C1—N1—O2−8.63 (15)
C3—C4—C7—O3−7.58 (16)C2—C1—N1—O2171.36 (10)
C5—C4—C7—C8−8.93 (15)O5—C9—O6—C10−0.60 (16)
C3—C4—C7—C8169.60 (9)C8—C9—O6—C10178.40 (9)
O3—C7—C8—N299.44 (13)C11—C10—O6—C9−173.74 (9)
C4—C7—C8—N2−77.85 (13)C8—N2—O4—C12−179.06 (9)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C2—H2···O4i0.932.563.3853 (14)148
C3—H3···O2ii0.932.503.3950 (16)162
C5—H5···O5iii0.932.353.1856 (14)150
C6—H6···O3iv0.932.463.3514 (16)160

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) −x+2, −y+1, −z; (iv) x+1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2157).

References

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