Ethyl (E)-3-acet­amido-2-butenoate

The crystal structure determination of the title compound, C₈H₁₃NO₃, shows that it is the E isomer. An N—H...O intermolecular hydrogen bond is observed and is responsible for the formation of infinite chains stretching along the b axis of the crystal.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.053
• wR factor = 0.153
• Data-to-parameter ratio = 19.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

The title compound, (I), is one of the products obtained from ethyl 3-amine-2-butenoate on reflux with acetic anhydride for a period of 48 h. This prochiral olefin is a model substrate studied in the asymmetric hydrogenation reaction (Hackler et al., 1985; Lubell et al., 1991). The structure determination of (I) was conducted in order to obtain more stereochemical information about the behaviour of these kinds of substrates in hydrogenation reactions.

The crystal structure of (I) (Fig. 1) shows that the molecule is nearly planar. The angles C3—C4—C5 [124.71 (19)°] and C4—C3—C8 [125.27 (18)°] are wider and N1—C3—C8 [112.12 (16)°] narrower than the value of 120°. This results in a close mutual repulsion between the methyl group on C3 and the carbonyl group on C4 (Table 1). The molecules in the crystal structure are interconnected by N—H···O hydrogen bonding (Table 2). As shown in the packing diagram (Fig. 2), the N—H···O hydrogen bond links the molecules along b axis.

S2. Experimental

The title compound was synthesized according theliterature (Zhu et al., 1999) A crystal suitable for X-ray analysis was grown slowly from a mixture of ethyl acetate and hexane at room temperature. ¹H NMR (400 MHz, acetone-d₆, p.p.m.): δ 1.24 (t, J = 7.1 Hz, 3H), 2.06 (s, 3H), 2.33 (s, 3H), 4.09 (q, J = 7.1 Hz, 2H), 6.89 (d, J = 1 Hz, 1H), 8.79 (br, 1H).

S3. Refinement

H atoms were included in the riding-model approximation with U_iso values equal to U_eq of the atom to which they were bound.

Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SHELXTL-NT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-NT; software used to prepare material for publication: SHELXTL-NT.

Figures

	Fig. 1. The molecular structure of (I), showing ellipsoids at the 30% probability level (Siemens, 1995).
	Fig. 2. Packing diagram for (I). The hydrogen bonds are indicated by dashed lines.

(E)-Ethyl 3-acetamido-2-butenoate

Crystal data

C8H13NO3	F(000) = 736
Mr = 171.19	Dx = 1.212 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 20.006 (4) Å	Cell parameters from 2174 reflections
b = 9.545 (2) Å	θ = 1–27.5°
c = 11.922 (2) Å	µ = 0.09 mm^−1
β = 124.479 (4)°	T = 294 K
V = 1876.7 (6) Å^3	Plate, colorless
Z = 8	0.34 × 0.28 × 0.10 mm

Data collection

Siemens SMART CCD area-detector diffractometer	2162 independent reflections
Radiation source: fine-focus sealed tube	1053 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ϕ and ω scans	θmax = 27.6°, θmin = 3.4°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −22→25
Tmin = 0.969, Tmax = 0.991	k = −12→12
6283 measured reflections	l = −15→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.153	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.07P)^2] where P = (Fo^2 + 2Fc^2)/3
2162 reflections	(Δ/σ)max < 0.001
112 parameters	Δρmax = 0.20 e Å^−3
0 restraints	Δρmin = −0.16 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.24031 (10)	0.98771 (15)	0.21996 (17)	0.0769 (5)
O2	0.43183 (11)	0.88023 (17)	0.06239 (18)	0.0906 (6)
O3	0.40086 (9)	1.09940 (14)	0.08209 (14)	0.0692 (5)
N1	0.27942 (10)	0.77021 (15)	0.20365 (16)	0.0551 (5)
H1A	0.2724	0.6830	0.2123	0.066*
C1	0.19104 (15)	0.7954 (2)	0.2785 (3)	0.0819 (8)
H1B	0.1506	0.8600	0.2661	0.123*
H1C	0.2267	0.7718	0.3732	0.123*
H1D	0.1652	0.7120	0.2267	0.123*
C2	0.23847 (12)	0.8610 (2)	0.2317 (2)	0.0564 (6)
C3	0.33135 (12)	0.79732 (19)	0.16286 (19)	0.0518 (5)
C4	0.34191 (12)	0.9254 (2)	0.1309 (2)	0.0592 (6)
H4	0.3128	0.9984	0.1356	0.071*
C5	0.39601 (13)	0.9594 (2)	0.0889 (2)	0.0623 (6)
C6	0.45348 (14)	1.1505 (2)	0.0444 (2)	0.0752 (7)
H6A	0.4350	1.1172	−0.0457	0.090*
H6B	0.5084	1.1174	0.1085	0.090*
C7	0.45111 (17)	1.3072 (3)	0.0457 (3)	0.0932 (9)
H7A	0.3961	1.3385	−0.0140	0.140*
H7B	0.4830	1.3443	0.0155	0.140*
H7C	0.4728	1.3392	0.1365	0.140*
C8	0.37290 (14)	0.6677 (2)	0.1617 (2)	0.0690 (6)
H8A	0.4154	0.6928	0.1509	0.104*
H8B	0.3344	0.6087	0.0874	0.104*
H8C	0.3956	0.6182	0.2459	0.104*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.1022 (13)	0.0467 (9)	0.1292 (14)	0.0032 (8)	0.0939 (12)	0.0030 (8)
O2	0.1093 (14)	0.0831 (11)	0.1347 (15)	0.0115 (10)	0.1024 (14)	0.0118 (10)
O3	0.0809 (11)	0.0683 (10)	0.0891 (11)	−0.0093 (8)	0.0667 (10)	0.0011 (7)
N1	0.0636 (11)	0.0454 (8)	0.0789 (11)	−0.0032 (8)	0.0538 (10)	−0.0026 (8)
C1	0.1037 (19)	0.0548 (12)	0.141 (2)	−0.0015 (12)	0.1015 (19)	0.0013 (13)
C2	0.0624 (13)	0.0481 (12)	0.0771 (14)	−0.0016 (10)	0.0505 (12)	−0.0029 (10)
C3	0.0489 (11)	0.0585 (12)	0.0567 (12)	−0.0010 (9)	0.0350 (11)	−0.0044 (9)
C4	0.0662 (14)	0.0564 (12)	0.0786 (14)	−0.0033 (10)	0.0552 (13)	−0.0036 (10)
C5	0.0644 (14)	0.0699 (14)	0.0705 (14)	−0.0014 (11)	0.0489 (13)	0.0012 (11)
C6	0.0704 (16)	0.0911 (17)	0.0808 (16)	−0.0113 (13)	0.0529 (14)	0.0127 (13)
C7	0.103 (2)	0.0963 (19)	0.0912 (18)	−0.0282 (15)	0.0613 (18)	0.0042 (14)
C8	0.0747 (15)	0.0631 (13)	0.0928 (16)	0.0095 (11)	0.0615 (14)	0.0032 (11)

Geometric parameters (Å, º)

O1—C2	1.220 (2)	C3—C8	1.495 (3)
O2—C5	1.200 (2)	C4—C5	1.463 (3)
O3—C5	1.345 (2)	C4—H4	0.9300
O3—C6	1.444 (2)	C6—C7	1.496 (3)
N1—C2	1.358 (2)	C6—H6A	0.9700
N1—C3	1.398 (2)	C6—H6B	0.9700
N1—H1A	0.8600	C7—H7A	0.9600
C1—C2	1.485 (3)	C7—H7B	0.9600
C1—H1B	0.9600	C7—H7C	0.9600
C1—H1C	0.9600	C8—H8A	0.9600
C1—H1D	0.9600	C8—H8B	0.9600
C3—C4	1.333 (3)	C8—H8C	0.9600
C5—O3—C6	116.38 (17)	O2—C5—C4	128.1 (2)
C2—N1—C3	129.64 (16)	O3—C5—C4	109.46 (17)
C2—N1—H1A	115.2	O3—C6—C7	107.52 (19)
C3—N1—H1A	115.2	O3—C6—H6A	110.2
C2—C1—H1B	109.5	C7—C6—H6A	110.2
C2—C1—H1C	109.5	O3—C6—H6B	110.2
H1B—C1—H1C	109.5	C7—C6—H6B	110.2
C2—C1—H1D	109.5	H6A—C6—H6B	108.5
H1B—C1—H1D	109.5	C6—C7—H7A	109.5
H1C—C1—H1D	109.5	C6—C7—H7B	109.5
O1—C2—N1	122.88 (17)	H7A—C7—H7B	109.5
O1—C2—C1	121.88 (17)	C6—C7—H7C	109.5
N1—C2—C1	115.24 (17)	H7A—C7—H7C	109.5
C4—C3—N1	122.61 (17)	H7B—C7—H7C	109.5
C4—C3—C8	125.27 (18)	C3—C8—H8A	109.5
N1—C3—C8	112.12 (16)	C3—C8—H8B	109.5
C3—C4—C5	124.71 (19)	H8A—C8—H8B	109.5
C3—C4—H4	117.6	C3—C8—H8C	109.5
C5—C4—H4	117.6	H8A—C8—H8C	109.5
O2—C5—O3	122.39 (18)	H8B—C8—H8C	109.5
C3—N1—C2—O1	2.3 (3)	C6—O3—C5—O2	−1.5 (3)
C3—N1—C2—C1	−177.4 (2)	C6—O3—C5—C4	178.83 (17)
C2—N1—C3—C4	−7.3 (3)	C3—C4—C5—O2	8.7 (4)
C2—N1—C3—C8	171.98 (19)	C3—C4—C5—O3	−171.69 (19)
N1—C3—C4—C5	179.42 (18)	C5—O3—C6—C7	−178.91 (19)
C8—C3—C4—C5	0.2 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1^i	0.86	2.10	2.943 (2)	165

Symmetry code: (i) −x+1/2, y−1/2, −z+1/2.