Ethyl (2E)-3-oxo-2-(pyrrolidin-2-yl­idene)butanoate

The pyrrolidine ring in the title compound, C₁₀H₁₅NO₃, adopts an envelope conformation. Both the secondary amine and acetyl groups participate in bifurcated intra- and inter­molecular hydrogen bonding; the former sets up a six-membered hydrogen-bonded ring, while the latter links the mol­ecules into centrosymmetric dimers.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.004 Å
• Disorder in main residue
• R factor = 0.064
• wR factor = 0.177
• Data-to-parameter ratio = 13.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.18
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C1
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.27
PLAT301_ALERT_3_C Main Residue  Disorder .........................       7.00 Perc.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H9B    ..  N1      ..       2.71 Ang.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

Ethyl (2E)-3-oxo-2-(pyrrolidin-2-ylidene)butanoate

Crystal data

C10H15NO3	F(000) = 424
Mr = 197.23	Dx = 1.306 Mg m^−3
Monoclinic, P21/n	Melting point = 365–366 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 7.5637 (3) Å	Cell parameters from 1355 reflections
b = 5.2527 (3) Å	θ = 2.7–27.8°
c = 25.4713 (13) Å	µ = 0.10 mm^−1
β = 97.554 (3)°	T = 173 K
V = 1003.19 (9) Å^3	Plate, colourless
Z = 4	0.45 × 0.25 × 0.04 mm

Data collection

Bruker APEX2 CCD area-detector diffractometer	1293 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.044
Graphite monochromator	θmax = 26.0°, θmin = 1.6°
φ and ω scans	h = −9→9
5713 measured reflections	k = −6→6
1972 independent reflections	l = −19→31

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)] = 0.064	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.177	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0818P)^2 + 0.4386P] where P = (Fo^2 + 2Fc^2)/3
1972 reflections	(Δ/σ)max < 0.001
143 parameters	Δρmax = 0.59 e Å^−3
2 restraints	Δρmin = −0.27 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	Occ. (<1)
C1	0.9455 (3)	0.7096 (5)	0.14563 (11)	0.0405 (7)
C2	0.7995 (3)	0.6845 (5)	0.10277 (10)	0.0321 (6)
C3	0.8131 (3)	0.4988 (5)	0.06159 (10)	0.0355 (6)
C4	0.9745 (3)	0.3292 (6)	0.06159 (12)	0.0460 (7)
H4A	0.9538	0.2087	0.0320	0.069*
H4B	0.9950	0.2351	0.0951	0.069*
H4C	1.0792	0.4338	0.0577	0.069*
C5	0.9850 (5)	1.0781 (8)	0.26448 (14)	0.0691 (10)
H5A	0.9623	1.2429	0.2468	0.104*
H5B	1.0749	1.0989	0.2956	0.104*
H5C	0.8742	1.0136	0.2756	0.104*
C6	1.0489 (4)	0.9006 (8)	0.22838 (14)	0.0657 (10)
H6A	1.0785	0.7365	0.2465	0.079*
H6B	1.1581	0.9679	0.2158	0.079*
C7	0.6433 (3)	0.8362 (5)	0.10029 (10)	0.0314 (6)
C8	0.6015 (3)	1.0453 (5)	0.13750 (11)	0.0381 (6)
H8A	0.6995	1.1715	0.1429	0.046*	0.58 (3)
H8B	0.5817	0.9748	0.1723	0.046*	0.58 (3)
H8C	0.6781	1.1958	0.1342	0.046*	0.42 (3)
H8D	0.6198	0.9857	0.1747	0.046*	0.42 (3)
C9	0.4314 (15)	1.165 (2)	0.1094 (5)	0.046 (3)	0.58 (3)
H9A	0.3450	1.1956	0.1347	0.055*	0.58 (3)
H9B	0.4585	1.3301	0.0933	0.055*	0.58 (3)
C9A	0.4032 (18)	1.110 (4)	0.1202 (7)	0.050 (5)	0.42 (3)
H9C	0.3281	1.0433	0.1461	0.060*	0.42 (3)
H9D	0.3859	1.2961	0.1170	0.060*	0.42 (3)
C10	0.3565 (3)	0.9831 (5)	0.06761 (12)	0.0434 (7)
H10A	0.2546	0.8876	0.0785	0.052*	0.58 (3)
H10B	0.3175	1.0716	0.0337	0.052*	0.58 (3)
H10C	0.2448	0.8841	0.0667	0.052*	0.42 (3)
H10D	0.3420	1.1095	0.0385	0.052*	0.42 (3)
N1	0.5077 (3)	0.8157 (5)	0.06322 (9)	0.0394 (6)
O1	1.0871 (3)	0.6058 (6)	0.14929 (10)	0.0909 (10)
O2	0.9118 (3)	0.8631 (5)	0.18419 (9)	0.0653 (7)
O3	0.6914 (2)	0.4674 (4)	0.02460 (7)	0.0492 (6)
H1	0.505 (4)	0.702 (6)	0.0388 (11)	0.041 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0331 (14)	0.0457 (16)	0.0422 (16)	0.0047 (12)	0.0035 (12)	−0.0053 (13)
C2	0.0275 (12)	0.0322 (13)	0.0365 (14)	0.0024 (10)	0.0040 (10)	0.0014 (11)
C3	0.0298 (12)	0.0354 (14)	0.0411 (15)	0.0046 (10)	0.0040 (11)	0.0014 (12)
C4	0.0354 (14)	0.0459 (17)	0.0558 (18)	0.0126 (12)	0.0023 (13)	−0.0079 (14)
C5	0.066 (2)	0.082 (3)	0.055 (2)	−0.0005 (19)	−0.0045 (17)	−0.013 (2)
C6	0.0429 (16)	0.080 (2)	0.068 (2)	0.0084 (16)	−0.0143 (15)	−0.022 (2)
C7	0.0316 (12)	0.0283 (13)	0.0344 (14)	−0.0006 (10)	0.0051 (11)	0.0010 (11)
C8	0.0360 (13)	0.0351 (14)	0.0433 (15)	0.0049 (11)	0.0053 (11)	−0.0039 (12)
C9	0.039 (4)	0.039 (4)	0.060 (5)	0.007 (3)	0.008 (4)	−0.013 (4)
C9A	0.033 (5)	0.062 (10)	0.055 (6)	0.022 (5)	0.003 (5)	−0.006 (6)
C10	0.0369 (14)	0.0434 (16)	0.0488 (17)	0.0170 (12)	0.0011 (12)	−0.0041 (13)
N1	0.0336 (12)	0.0412 (14)	0.0415 (13)	0.0120 (10)	−0.0026 (10)	−0.0096 (12)
O1	0.0529 (14)	0.123 (2)	0.0868 (19)	0.0440 (15)	−0.0292 (12)	−0.0490 (17)
O2	0.0436 (11)	0.0846 (17)	0.0612 (14)	0.0201 (11)	−0.0171 (10)	−0.0331 (13)
O3	0.0384 (10)	0.0552 (13)	0.0504 (12)	0.0165 (9)	−0.0072 (9)	−0.0186 (10)

Geometric parameters (Å, º)

C1—O1	1.194 (3)	C8—C9	1.524 (10)
C1—O2	1.321 (3)	C8—C9A	1.544 (11)
C1—C2	1.454 (3)	C8—H8A	0.9900
C2—C7	1.419 (3)	C8—H8B	0.9900
C2—C3	1.446 (4)	C8—H8C	0.9900
C3—O3	1.239 (3)	C8—H8D	0.9900
C3—C4	1.511 (3)	C9—C10	1.486 (9)
C4—H4A	0.9800	C9—H9A	0.9900
C4—H4B	0.9800	C9—H9B	0.9900
C4—H4C	0.9800	C9A—C10	1.495 (12)
C5—C6	1.437 (5)	C9A—H9C	0.9900
C5—H5A	0.9800	C9A—H9D	0.9900
C5—H5B	0.9800	C10—N1	1.459 (3)
C5—H5C	0.9800	C10—H10A	0.9900
C6—O2	1.440 (3)	C10—H10B	0.9900
C6—H6A	0.9900	C10—H10C	0.9900
C6—H6B	0.9900	C10—H10D	0.9900
C7—N1	1.304 (3)	N1—H1	0.86 (3)
C7—C8	1.511 (3)
O1—C1—O2	118.6 (3)	C9A—C8—H8C	111.0
O1—C1—C2	127.0 (3)	H8B—C8—H8C	122.2
O2—C1—C2	114.3 (2)	C7—C8—H8D	110.8
C7—C2—C3	119.0 (2)	C9—C8—H8D	125.7
C7—C2—C1	121.9 (2)	C9A—C8—H8D	110.6
C3—C2—C1	119.1 (2)	H8A—C8—H8D	94.1
O3—C3—C2	121.7 (2)	H8C—C8—H8D	108.9
O3—C3—C4	116.2 (2)	C10—C9—C8	106.8 (6)
C2—C3—C4	122.2 (2)	C10—C9—H9A	110.4
C3—C4—H4A	109.5	C8—C9—H9A	110.4
C3—C4—H4B	109.5	C10—C9—H9B	110.4
H4A—C4—H4B	109.5	C8—C9—H9B	110.4
C3—C4—H4C	109.5	H9A—C9—H9B	108.6
H4A—C4—H4C	109.5	C10—C9A—C8	105.4 (8)
H4B—C4—H4C	109.5	C10—C9A—H9C	110.7
C6—C5—H5A	109.5	C8—C9A—H9C	110.7
C6—C5—H5B	109.5	C10—C9A—H9D	110.7
H5A—C5—H5B	109.5	C8—C9A—H9D	110.7
C6—C5—H5C	109.5	H9C—C9A—H9D	108.8
H5A—C5—H5C	109.5	N1—C10—C9	102.4 (4)
H5B—C5—H5C	109.5	N1—C10—C9A	104.0 (5)
C5—C6—O2	108.7 (3)	N1—C10—H10A	111.3
C5—C6—H6A	109.9	C9—C10—H10A	111.3
O2—C6—H6A	109.9	C9A—C10—H10A	94.3
C5—C6—H6B	109.9	N1—C10—H10B	111.3
O2—C6—H6B	109.9	C9—C10—H10B	111.3
H6A—C6—H6B	108.3	C9A—C10—H10B	125.5
N1—C7—C2	123.8 (2)	H10A—C10—H10B	109.2
N1—C7—C8	107.7 (2)	N1—C10—H10C	110.9
C2—C7—C8	128.5 (2)	C9—C10—H10C	126.8
C7—C8—C9	103.8 (4)	C9A—C10—H10C	110.8
C7—C8—C9A	104.8 (5)	H10B—C10—H10C	94.1
C7—C8—H8A	111.0	N1—C10—H10D	111.0
C9—C8—H8A	111.0	C9—C10—H10D	95.6
C9A—C8—H8A	125.1	C9A—C10—H10D	111.2
C7—C8—H8B	111.0	H10A—C10—H10D	122.4
C9—C8—H8B	111.0	H10C—C10—H10D	109.0
C9A—C8—H8B	94.7	C7—N1—C10	116.4 (2)
H8A—C8—H8B	109.0	C7—N1—H1	121.3 (18)
C7—C8—H8C	110.7	C10—N1—H1	122.1 (18)
C9—C8—H8C	95.6	C1—O2—C6	118.4 (2)
O1—C1—C2—C7	−173.9 (3)	C7—C8—C9—C10	15.9 (11)
O2—C1—C2—C7	7.0 (4)	C9A—C8—C9—C10	−79 (3)
O1—C1—C2—C3	6.4 (5)	C7—C8—C9A—C10	−13.1 (16)
O2—C1—C2—C3	−172.7 (2)	C9—C8—C9A—C10	76 (2)
C7—C2—C3—O3	−0.7 (4)	C8—C9—C10—N1	−16.4 (10)
C1—C2—C3—O3	179.0 (2)	C8—C9—C10—C9A	81 (3)
C7—C2—C3—C4	−179.7 (2)	C8—C9A—C10—N1	11.8 (16)
C1—C2—C3—C4	0.1 (4)	C8—C9A—C10—C9	−75 (2)
C3—C2—C7—N1	1.3 (4)	C2—C7—N1—C10	178.6 (2)
C1—C2—C7—N1	−178.4 (2)	C8—C7—N1—C10	−1.9 (3)
C3—C2—C7—C8	−178.1 (2)	C9—C10—N1—C7	11.9 (7)
C1—C2—C7—C8	2.2 (4)	C9A—C10—N1—C7	−6.7 (11)
N1—C7—C8—C9	−8.8 (7)	O1—C1—O2—C6	1.0 (5)
C2—C7—C8—C9	170.7 (7)	C2—C1—O2—C6	−179.8 (3)
N1—C7—C8—C9A	9.4 (11)	C5—C6—O2—C1	178.6 (3)
C2—C7—C8—C9A	−171.1 (11)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3	0.86 (3)	1.94 (3)	2.570 (3)	129 (2)
N1—H1···O3^i	0.86 (3)	2.23 (3)	2.932 (3)	138 (2)
C9—H9B···N1^ii	0.99	2.71	3.6853 (2)	170

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