Ethyl 4-methyl-1H-pyrrole-3-carboxyl­ate

The mol­ecule of the title compound, C₈H₁₁NO₂, is nearly planar, possibly due to aromatic conjugation of the carboxyl­ate group with the aromatic pyrrole ring. The mol­ecules form infinite supra­molecular chains along the [101] direction via inter­molecular N—H...O hydrogen bonding.

Key indicators

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.045
• wR factor = 0.124
• Data-to-parameter ratio = 18.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT413_ALERT_2_C Short Inter XH3 .. XHn     H52    ..  H52     ..       2.13 Ang.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 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
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The title compound, C₈H₁₁NO₂, was prepared as a tentative ligand for transition metal complexes.

The molecular structure is shown in Fig. 1. The molecule is nearly planar which might be due to aromatic conjugation of the carboxyl group with the aromatic pyrrol ring, and packing effects for the ethyl group (Fig. 2).

In the crystal structure, the molecules are connected to form supramolecular chains via N—H···O hydrogen bonds (Table 1).

For the structures of a series of imidazole-4,5-dicarboxylic-acid derivatives see Baures et al. (2002).

Related literature

The title compound was prepared according to a synthesis described b Büchel et al. (1994). For the structure of a related compound, see: Baures et al. (2002).

For related literature, see: Cheng et al. (1976).

S2. Experimental

The title compound was prepared according to a synthesis described in Büchel et al. (1994). The title compound was obtained upon reaction of 4-methylphenylsulfonylmethylisocyanide with 2-butenoic acid ethyl ester in a mixture of dry ether and dimethylsulfoxide (2:1) under reductive conditions (NaH) at room temperature. After 30 minutes the excess sodium hydride was quenched by the addition of water. After another 30 minutes the reaction mixture was extracted with diethylether three times. The combined organic phases were combined yielding a yellow oil. After column chromatography on aluminium oxide with dichloromethane as solvent and removal of the solvent of the first fraction, light yellow crystals were obtained.

S3. Refinement

All H atoms were placed in calculated positions with C—H = 0.95 (aromatic), 0.98(methyl), 0.99 Å (methylene) an N—H = 0.88 Å, and refined as riding on their parent atoms with one common isotropic displacement parameter.

Computing details

Data collection: COLLECT (Nonius, 2004); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); 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); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The molecular structure of (I), with atom labels and anisotropic displacement ellipsoids (drawn at 50% probability level) for non-H atoms.
	Fig. 2. Packing of two closest non-hydrogen-bonded neighbours of (I) in a normal view.
	Fig. 3. Hydrogen-bonded chains, view along [0 - 1 0], 0.0 < y < 0.5 only.

Ethyl 4-methyl-1H-pyrrole-3-carboxylate

Crystal data

C8H11NO2	F(000) = 656
Mr = 153.18	Dx = 1.239 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 8547 reflections
a = 11.3757 (5) Å	θ = 3.1–27.5°
b = 10.9074 (4) Å	µ = 0.09 mm^−1
c = 14.1470 (4) Å	T = 200 K
β = 110.644 (2)°	Block, light yellow
V = 1642.64 (11) Å^3	0.23 × 0.12 × 0.08 mm
Z = 8

Data collection

Enraf–Nonius KappaCCD diffractometer	1468 reflections with I > 2σ(I)
Radiation source: rotating anode	Rint = 0.020
MONTEL, graded multilayered X-ray optics monochromator	θmax = 27.5°, θmin = 3.4°
ω scan	h = −14→14
3569 measured reflections	k = −14→14
1859 independent reflections	l = −17→17

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.124	Only H-atom displacement parameters refined
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0522P)^2 + 1.2343P] where P = (Fo^2 + 2Fc^2)/3
1859 reflections	(Δ/σ)max < 0.001
103 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.17019 (10)	0.42295 (10)	0.01285 (8)	0.0377 (3)
O2	0.02995 (10)	0.26964 (12)	−0.03239 (8)	0.0436 (3)
C3	0.18984 (13)	0.26544 (14)	0.12870 (10)	0.0307 (3)
N1	0.33745 (12)	0.23332 (12)	0.27728 (9)	0.0376 (3)
H101	0.4069	0.2405	0.3302	0.0626 (18)*
C2	0.15334 (14)	0.16238 (14)	0.17421 (11)	0.0332 (3)
C6	0.12186 (13)	0.31647 (14)	0.02949 (11)	0.0316 (3)
C4	0.30409 (14)	0.30630 (15)	0.19499 (11)	0.0350 (4)
H41	0.3509	0.3738	0.1845	0.0626 (18)*
C7	0.10894 (16)	0.47856 (16)	−0.08579 (12)	0.0399 (4)
H71	0.0194	0.4948	−0.0970	0.0626 (18)*
H72	0.1136	0.4230	−0.1397	0.0626 (18)*
C5	0.03638 (16)	0.08732 (17)	0.13147 (13)	0.0460 (4)
H51	0.0417	0.0157	0.1746	0.0626 (18)*
H52	0.0274	0.0600	0.0633	0.0626 (18)*
H53	−0.0366	0.1371	0.1285	0.0626 (18)*
C1	0.24662 (15)	0.14637 (15)	0.26568 (11)	0.0371 (4)
H11	0.2483	0.0848	0.3136	0.0626 (18)*
C8	0.1760 (2)	0.59605 (18)	−0.08746 (16)	0.0552 (5)
H81	0.1696	0.6507	−0.0345	0.0626 (18)*
H82	0.1377	0.6355	−0.1535	0.0626 (18)*
H83	0.2647	0.5789	−0.0755	0.0626 (18)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0391 (6)	0.0381 (6)	0.0306 (6)	0.0009 (5)	0.0055 (5)	0.0037 (4)
O2	0.0361 (6)	0.0550 (7)	0.0280 (6)	−0.0057 (5)	−0.0031 (4)	0.0044 (5)
C3	0.0289 (7)	0.0349 (8)	0.0246 (7)	0.0040 (6)	0.0049 (6)	−0.0026 (6)
N1	0.0339 (7)	0.0438 (8)	0.0257 (6)	0.0035 (6)	−0.0013 (5)	−0.0025 (5)
C2	0.0315 (7)	0.0366 (8)	0.0274 (7)	0.0023 (6)	0.0055 (6)	−0.0025 (6)
C6	0.0288 (7)	0.0367 (8)	0.0274 (7)	0.0039 (6)	0.0076 (6)	−0.0016 (6)
C4	0.0335 (8)	0.0359 (8)	0.0292 (7)	0.0021 (6)	0.0032 (6)	−0.0033 (6)
C7	0.0442 (9)	0.0423 (9)	0.0312 (8)	0.0086 (7)	0.0110 (7)	0.0070 (6)
C5	0.0418 (9)	0.0492 (10)	0.0404 (9)	−0.0076 (8)	0.0063 (7)	0.0031 (7)
C1	0.0395 (8)	0.0392 (9)	0.0286 (8)	0.0035 (7)	0.0069 (6)	0.0011 (6)
C8	0.0637 (13)	0.0478 (11)	0.0561 (12)	0.0024 (9)	0.0236 (10)	0.0128 (9)

Geometric parameters (Å, º)

O1—C6	1.3408 (18)	C4—H41	0.9500
O1—C7	1.4544 (18)	C7—C8	1.496 (3)
O2—C6	1.2145 (18)	C7—H71	0.9900
C3—C4	1.381 (2)	C7—H72	0.9900
C3—C2	1.428 (2)	C5—H51	0.9800
C3—C6	1.453 (2)	C5—H52	0.9800
N1—C4	1.350 (2)	C5—H53	0.9800
N1—C1	1.369 (2)	C1—H11	0.9500
N1—H101	0.8800	C8—H81	0.9800
C2—C1	1.365 (2)	C8—H82	0.9800
C2—C5	1.496 (2)	C8—H83	0.9800
C6—O1—C7	116.25 (12)	O1—C7—H72	110.2
C4—C3—C2	107.54 (13)	C8—C7—H72	110.2
C4—C3—C6	125.81 (14)	H71—C7—H72	108.5
C2—C3—C6	126.62 (13)	C2—C5—H51	109.5
C4—N1—C1	109.53 (13)	C2—C5—H52	109.5
C4—N1—H101	125.2	H51—C5—H52	109.5
C1—N1—H101	125.2	C2—C5—H53	109.5
C1—C2—C3	106.00 (13)	H51—C5—H53	109.5
C1—C2—C5	126.62 (15)	H52—C5—H53	109.5
C3—C2—C5	127.37 (13)	C2—C1—N1	109.07 (14)
O2—C6—O1	122.68 (14)	C2—C1—H11	125.5
O2—C6—C3	124.38 (15)	N1—C1—H11	125.5
O1—C6—C3	112.94 (12)	C7—C8—H81	109.5
N1—C4—C3	107.85 (14)	C7—C8—H82	109.5
N1—C4—H41	126.1	H81—C8—H82	109.5
C3—C4—H41	126.1	C7—C8—H83	109.5
O1—C7—C8	107.33 (14)	H81—C8—H83	109.5
O1—C7—H71	110.2	H82—C8—H83	109.5
C8—C7—H71	110.2
C4—C3—C2—C1	0.30 (17)	C2—C3—C6—O1	171.47 (13)
C6—C3—C2—C1	178.57 (14)	C1—N1—C4—C3	−0.30 (17)
C4—C3—C2—C5	179.78 (15)	C2—C3—C4—N1	0.00 (17)
C6—C3—C2—C5	−2.0 (3)	C6—C3—C4—N1	−178.29 (14)
C7—O1—C6—O2	−2.1 (2)	C6—O1—C7—C8	179.17 (13)
C7—O1—C6—C3	178.68 (12)	C3—C2—C1—N1	−0.48 (17)
C4—C3—C6—O2	170.21 (15)	C5—C2—C1—N1	−179.97 (15)
C2—C3—C6—O2	−7.7 (2)	C4—N1—C1—C2	0.50 (17)
C4—C3—C6—O1	−10.6 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H101···O2^i	0.88	1.96	2.809 (2)	163

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