(Z)-Methyl 2-methoxy-imino-3-oxo-butanoate.

The title compound, C(6)H(9)NO(4), was prepared stereoselectively as a precursor for 1-aza-dienes in a study of hetero-Diels-Alder reactions. The configuration of the C=N double bond was found to be Z, corroborating earlier assignments of similar compounds based only on NMR and IR spectroscopic analysis.

Related literature

For related literature, see: Buehler (1967 ▶); Corrêa & Moran (1999 ▶); Fletcher et al. (2006 ▶); François et al. (2004 ▶); Jirman et al. (1990 ▶); Karabatsos & Taller (1968 ▶); Levy & Nelson (1972 ▶); Lu & Arndt (2007 ▶).

Experimental

Crystal data

C6H9NO4

M = 159.14

Orthorhombic,

a = 8.3410 (17) Å

b = 13.410 (3) Å

c = 7.2900 (15) Å

V = 815.4 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.11 mm−1

T = 291 (1) K

0.2 × 0.2 × 0.2 mm

Data collection

Nonius KappaCCD diffractometer

Absorption correction: none

3104 measured reflections

899 independent reflections

536 reflections with I > 2σ(I)

R int = 0.045

Refinement

R[F 2 > 2σ(F 2)] = 0.027

wR(F 2) = 0.057

S = 1.09

899 reflections

104 parameters

1 restraint

H-atom parameters constrained

Δρmax = 0.08 e Å−3

Δρmin = −0.11 e Å−3

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808004376/hb2698sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808004376/hb2698Isup2.hkl

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

C6H9NO4	F000 = 336
Mr = 159.14	Dx = 1.296 Mg m−3
Orthorhombic, Pna21	Mo Kα radiation λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 3104 reflections
a = 8.3410 (17) Å	θ = 3.0–27.5º
b = 13.410 (3) Å	µ = 0.11 mm−1
c = 7.2900 (15) Å	T = 291 (1) K
V = 815.4 (3) Å3	Cube, colourless
Z = 4	0.2 × 0.2 × 0.2 mm

Nonius KappaCCD diffractometer	899 independent reflections
Radiation source: fine-focus sealed tube	536 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.045
Detector resolution: 19 vertical, 18 horizontal pixels mm-1	θmax = 26.4º
T = 291(1) K	θmin = 3.9º
213 frames via ω–rotation (Δω = 1%) and two times 40 s per frame (four sets at different κ–angles) scans	h = −10→10
Absorption correction: none	k = −16→16
3104 measured reflections	l = −9→9

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)] = 0.027	H-atom parameters constrained
wR(F2) = 0.057	w = 1/[σ2(Fo2) + (0.0206P)2] where P = (Fo2 + 2Fc2)/3
S = 1.09	(Δ/σ)max < 0.001
899 reflections	Δρmax = 0.08 e Å−3
104 parameters	Δρmin = −0.11 e Å−3
1 restraint	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.087 (6)

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.

	x	y	z	Uiso*/Ueq
O1	0.14686 (19)	0.12432 (11)	0.8457 (2)	0.0633 (5)
O2	0.1931 (2)	0.03995 (12)	0.4285 (2)	0.0784 (6)
O3	0.4017 (2)	0.23981 (12)	0.3446 (3)	0.0923 (7)
O4	0.4114 (2)	0.03491 (11)	0.6049 (2)	0.0634 (5)
N1	0.19750 (19)	0.20788 (12)	0.7495 (3)	0.0536 (5)
C1	0.2847 (3)	0.07762 (15)	0.5349 (3)	0.0520 (6)
C3	0.2673 (2)	0.18321 (15)	0.5998 (3)	0.0463 (5)
C5	0.3291 (3)	0.26405 (17)	0.4804 (3)	0.0557 (6)
C7	0.0702 (3)	0.15466 (19)	1.0136 (3)	0.0749 (8)
H7A	0.0349	0.0967	1.0796	0.112*
H7B	−0.0205	0.1961	0.9857	0.112*
H7C	0.1449	0.1914	1.0875	0.112*
C8	0.4383 (4)	−0.06865 (16)	0.5537 (3)	0.0819 (9)
H8A	0.5226	−0.0960	0.6279	0.123*
H8D	0.4683	−0.0721	0.4268	0.123*
H8B	0.3416	−0.1061	0.5727	0.123*
C9	0.3008 (3)	0.37018 (15)	0.5307 (4)	0.0674 (7)
H9A	0.3481	0.4128	0.4397	0.101*
H9B	0.3484	0.3836	0.6480	0.101*
H9D	0.1875	0.3826	0.5367	0.101*

	U11	U22	U33	U12	U13	U23
O1	0.0881 (11)	0.0498 (9)	0.0519 (9)	−0.0045 (8)	0.0208 (9)	0.0002 (9)
O2	0.0868 (13)	0.0657 (11)	0.0828 (13)	0.0028 (9)	−0.0205 (12)	−0.0202 (11)
O3	0.1322 (17)	0.0691 (12)	0.0755 (13)	−0.0101 (10)	0.0492 (14)	−0.0068 (11)
O4	0.0676 (10)	0.0551 (9)	0.0675 (10)	0.0137 (8)	−0.0078 (9)	−0.0037 (9)
N1	0.0625 (12)	0.0471 (11)	0.0510 (12)	−0.0028 (9)	0.0046 (12)	0.0004 (10)
C1	0.0601 (14)	0.0494 (13)	0.0467 (14)	−0.0018 (13)	0.0041 (14)	−0.0023 (13)
C3	0.0483 (12)	0.0491 (13)	0.0415 (12)	0.0010 (10)	−0.0001 (12)	−0.0037 (12)
C5	0.0615 (16)	0.0567 (15)	0.0490 (14)	−0.0031 (12)	0.0063 (13)	−0.0008 (13)
C7	0.0981 (19)	0.0731 (17)	0.0535 (16)	−0.0063 (16)	0.0276 (15)	−0.0040 (14)
C8	0.1075 (19)	0.0597 (17)	0.079 (2)	0.0278 (14)	0.0040 (16)	0.0008 (15)
C9	0.0773 (15)	0.0517 (14)	0.0732 (17)	−0.0057 (13)	0.0087 (13)	0.0009 (15)

O1—N1	1.387 (2)	C7—H7A	0.9600
O1—C7	1.440 (3)	C7—H7B	0.9600
O2—C1	1.200 (3)	C7—H7C	0.9600
O3—C5	1.205 (3)	C8—H8A	0.9600
O4—C1	1.306 (3)	C8—H8D	0.9600
O4—C8	1.455 (2)	C8—H8B	0.9600
N1—C3	1.281 (3)	C9—H9A	0.9600
C1—C3	1.500 (3)	C9—H9B	0.9600
C3—C5	1.483 (3)	C9—H9D	0.9600
C5—C9	1.489 (3)
N1—O1—C7	109.67 (16)	O1—C7—H7C	109.5
C1—O4—C8	116.29 (19)	H7A—C7—H7C	109.5
C3—N1—O1	111.12 (17)	H7B—C7—H7C	109.5
O2—C1—O4	125.7 (2)	O4—C8—H8A	109.5
O2—C1—C3	122.6 (2)	O4—C8—H8D	109.5
O4—C1—C3	111.7 (2)	H8A—C8—H8D	109.5
N1—C3—C5	118.01 (19)	O4—C8—H8B	109.5
N1—C3—C1	123.8 (2)	H8A—C8—H8B	109.5
C5—C3—C1	118.1 (2)	H8D—C8—H8B	109.5
O3—C5—C3	117.4 (2)	C5—C9—H9A	109.5
O3—C5—C9	122.7 (2)	C5—C9—H9B	109.5
C3—C5—C9	119.9 (2)	H9A—C9—H9B	109.5
O1—C7—H7A	109.5	C5—C9—H9D	109.5
O1—C7—H7B	109.5	H9A—C9—H9D	109.5
H7A—C7—H7B	109.5	H9B—C9—H9D	109.5