2-Ethyl 4-methyl 5-ethyl-3-methyl-1H-pyrrole-2,4-dicarboxyl­ate

Lu, G.-F.; Zhu, M.; Zhu, W.-H.; Ou, Z.-P.

doi:10.1107/S1600536812001729

organic compounds

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ISSN: 2056-9890

Volume 68| Part 2| February 2012| Page o483

doi:10.1107/S1600536812001729

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2-Ethyl 4-methyl 5-ethyl-3-methyl-1H-pyrrole-2,4-dicarboxylate

Gui-Fen Lu,^a ^* Min Zhu,^a Wei-Hua Zhu ^a and Zhong-Ping Ou ^a

^aSchool of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People's Republic of China
^*Correspondence e-mail: luguifen8012@yahoo.com.cn

(Received 6 January 2012; accepted 14 January 2012; online 21 January 2012)

The title pyrrole derivative compound, C₁₂H₁₇NO₄, was synthesized from methyl 3-oxopentanoate by a Knorr-type reaction and contains a pyrrole ring to which two diagonal alkoxycarbonyl groups and two diagonal alkyl substituents are attached. The methylcarbonyl and ethylcarbonyl substituents are approximately co-planar with the pyrrole ring, making dihedral angles of 5.64 (2) and 3.44 (1)°, respectively. In the crystal, adjacent molecules are assembled by pairs of N—H⋯O hydrogen bonds into dimers in a head-to-head mode.

Related literature

For applications of polysubstituted pyrroles, see: Brockmann & Tour, (1995 ); Guilard et al. (2001 ); Trofimov et al. (2004 ). For related structures, see: Lu et al. (2011 ); Takaya et al. (2001 ). For complexes of pyrrole derivatives, see: Fan et al. (2008 ); Ou et al. (2009 ); Paixão et al. (2003 ); Yamamoto et al. (1986 ).

Experimental

Crystal data

C₁₂H₁₇NO₄
M_r = 239.27
Triclinic, $[P \overline 1]$
a = 7.2827 (10) Å
b = 8.8573 (12) Å
c = 11.1806 (16) Å
α = 77.948 (2)°
β = 73.135 (2)°
γ = 69.970 (2)°
V = 643.62 (15) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.15 × 0.12 × 0.06 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.986, T_max = 0.995
3249 measured reflections
2255 independent reflections
1891 reflections with I > 2σ(I)
R_int = 0.018

Refinement

R[F² > 2σ(F²)] = 0.067
wR(F²) = 0.220
S = 1.11
2255 reflections
159 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.51 e Å⁻³
Δρ_min = −0.36 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1ⁱ	0.84 (1)	2.07 (1)	2.883 (3)	165 (2)
Symmetry code: (i) -x, -y+1, -z.

Data collection: APEX2 (Bruker, 2004 ); cell refinement: SAINT-Plus (Bruker, 2001 ); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812001729/vm2149sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812001729/vm2149Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812001729/vm2149Isup3.cml

checkCIF report

Comment top

Polysubstituted pyrroles have been paid much attention because of their wide application in the preparation of porphyrins (Trofimov et al., 2004), corroles (Guilard et al., 2001) and as monomers for polymer chemistry (Brockmann & Tour, 1995; Paixão et al., 2003). In view of the importance of the 2-(alkoxycarbonyl)pyrrole derivatives (Fan et al., 2008; Lu et al., 2011; Takaya et al., 2001), the title compound was synthesized and characterized by X-ray diffraction.

As shown in Fig. 1, the compound has a five-membered pyrrole ring as skeleton and four substituents. The methoxycarbonyl and ethoxycarbonyl groups are located on two diagonal carbon atoms of the pyrrole skeleton, which is also true for the methyl and ethyl substituents, forming an asymmetrical molecule. Adjacent molecules are assembled in a head to head mode by hydrogen bonding between the donor atom N₁ and acceptor atom O₁ (symmetry code: -x, 1 - y, -z) (Table 1, Fig. 2). The bond distances are in the normal range of the similar species reported by Yamamoto et al. (1986).

Related literature top

For applications of polysubstituted pyrroles, see: Brockmann & Tour, (1995); Guilard et al. (2001); Trofimov et al. (2004). For related structures, see: Lu et al. (2011); Takaya et al. (2001). For complexes of pyrrole derivatives, see: Fan et al. (2008); Ou et al. (2009); Paixão et al. (2003); Yamamoto et al. (1986).

Experimental top

The title compound was synthesized from ethyl acetoacetate and methyl 3-oxopentanoate through oximination, Claisen condensation and reductive condensation according to the method reported by Ou et al. (2009). Single crystals suitable for X-ray measurements were grown from ethanol by slowly evaporation at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure with the unique atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. Dimer formation in the crystal packing.

2-Ethyl 4-methyl 5-ethyl-3-methyl-1H-pyrrole-2,4-dicarboxylate top

Crystal data top

C₁₂H₁₇NO₄	Z = 2
M_r = 239.27	F(000) = 256
Triclinic, P1	D_x = 1.235 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2827 (10) Å	Cell parameters from 1663 reflections
b = 8.8573 (12) Å	θ = 2.4–26.8°
c = 11.1806 (16) Å	µ = 0.09 mm⁻¹
α = 77.948 (2)°	T = 293 K
β = 73.135 (2)°	Sheet, colorless
γ = 69.970 (2)°	0.15 × 0.12 × 0.06 mm
V = 643.62 (15) Å³

Data collection top

Bruker APEXII CCD area-detector diffractometer	2255 independent reflections
Radiation source: fine-focus sealed tube	1891 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.018
ϕ and ω scans	θ_max = 25.0°, θ_min = 2.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −8→6
T_min = 0.986, T_max = 0.995	k = −10→9
3249 measured reflections	l = −13→13

Refinement top

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)] = 0.067	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.220	w = 1/[σ²(F_o²) + (0.1366P)² + 0.1514P] where P = (F_o² + 2F_c²)/3
S = 1.11	(Δ/σ)_max < 0.001
2255 reflections	Δρ_max = 0.51 e Å⁻³
159 parameters	Δρ_min = −0.36 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: 0.046 (17)

Crystal data top

C₁₂H₁₇NO₄	γ = 69.970 (2)°
M_r = 239.27	V = 643.62 (15) Å³
Triclinic, P1	Z = 2
a = 7.2827 (10) Å	Mo Kα radiation
b = 8.8573 (12) Å	µ = 0.09 mm⁻¹
c = 11.1806 (16) Å	T = 293 K
α = 77.948 (2)°	0.15 × 0.12 × 0.06 mm
β = 73.135 (2)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	2255 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	1891 reflections with I > 2σ(I)
T_min = 0.986, T_max = 0.995	R_int = 0.018
3249 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.067	1 restraint
wR(F²) = 0.220	H atoms treated by a mixture of independent and constrained refinement
S = 1.11	Δρ_max = 0.51 e Å⁻³
2255 reflections	Δρ_min = −0.36 e Å⁻³
159 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
C10	0.3898 (4)	−0.0962 (3)	−0.1197 (2)	0.0550 (6)
H10A	0.4158	−0.2064	−0.0808	0.082*
H10B	0.5149	−0.0720	−0.1553	0.082*
H10C	0.3217	−0.0814	−0.1849	0.082*
C11	0.2132 (4)	−0.1884 (3)	0.1807 (2)	0.0560 (6)
C12	0.3494 (6)	−0.4707 (4)	0.1703 (3)	0.0963 (11)
H12A	0.4249	−0.5445	0.1089	0.144*
H12B	0.2222	−0.4899	0.2098	0.144*
H12C	0.4232	−0.4871	0.2328	0.144*
O4	0.3164 (3)	−0.3073 (2)	0.10932 (18)	0.0785 (6)
O3	0.1512 (4)	−0.2162 (3)	0.29184 (19)	0.0950 (8)
H1A	0.020 (3)	0.3365 (14)	0.079 (2)	0.052 (7)*
C1	0.1913 (3)	0.1820 (3)	−0.04297 (19)	0.0461 (5)
C2	0.2603 (3)	0.0150 (2)	−0.02273 (19)	0.0439 (5)
C3	0.1853 (3)	−0.0280 (3)	0.1078 (2)	0.0470 (6)
C4	0.0707 (3)	0.1150 (3)	0.1615 (2)	0.0491 (6)
C5	0.2114 (4)	0.3014 (3)	−0.1527 (2)	0.0569 (6)
C6	0.3253 (8)	0.3461 (4)	−0.3746 (3)	0.1147 (15)
H6A	0.1902	0.4037	−0.3852	0.138*
H6B	0.3889	0.4250	−0.3721	0.138*
C7	0.4382 (8)	0.2543 (6)	−0.4772 (3)	0.1304 (17)
H7A	0.4460	0.3259	−0.5547	0.196*
H7B	0.3730	0.1779	−0.4801	0.196*
H7C	0.5715	0.1974	−0.4659	0.196*
C8	−0.0423 (4)	0.1442 (3)	0.2940 (2)	0.0621 (7)
H8A	−0.1565	0.2409	0.2921	0.075*
H8B	−0.0940	0.0540	0.3344	0.075*
C9	0.0830 (5)	0.1639 (4)	0.3707 (3)	0.0857 (9)
H9A	0.0028	0.1823	0.4542	0.129*
H9B	0.1322	0.2546	0.3324	0.129*
H9C	0.1946	0.0676	0.3748	0.129*
N1	0.0782 (3)	0.2382 (2)	0.07013 (17)	0.0503 (5)
O1	0.1384 (3)	0.4462 (2)	−0.15035 (18)	0.0821 (7)
O2	0.3170 (3)	0.2368 (2)	−0.25857 (16)	0.0748 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C10	0.0654 (14)	0.0407 (12)	0.0528 (13)	−0.0105 (10)	−0.0084 (10)	−0.0104 (10)
C11	0.0628 (13)	0.0460 (13)	0.0535 (13)	−0.0180 (10)	−0.0088 (10)	0.0016 (10)
C12	0.130 (3)	0.0388 (15)	0.097 (2)	−0.0178 (16)	−0.016 (2)	0.0119 (14)
O4	0.1114 (15)	0.0334 (10)	0.0680 (12)	−0.0114 (9)	−0.0062 (11)	0.0025 (8)
O3	0.1393 (19)	0.0586 (12)	0.0578 (12)	−0.0263 (12)	0.0044 (12)	0.0097 (9)
C1	0.0501 (11)	0.0386 (11)	0.0423 (11)	−0.0088 (8)	−0.0071 (8)	−0.0033 (8)
C2	0.0436 (10)	0.0389 (11)	0.0467 (11)	−0.0113 (9)	−0.0087 (8)	−0.0047 (8)
C3	0.0480 (11)	0.0404 (11)	0.0495 (12)	−0.0137 (9)	−0.0083 (9)	−0.0025 (9)
C4	0.0478 (11)	0.0438 (12)	0.0483 (12)	−0.0118 (9)	−0.0047 (9)	−0.0027 (9)
C5	0.0677 (14)	0.0397 (12)	0.0484 (13)	−0.0075 (10)	−0.0055 (10)	−0.0003 (9)
C6	0.183 (4)	0.0601 (18)	0.0511 (17)	−0.014 (2)	0.007 (2)	0.0112 (14)
C7	0.186 (4)	0.123 (3)	0.0515 (19)	−0.033 (3)	−0.008 (2)	0.001 (2)
C8	0.0667 (14)	0.0542 (14)	0.0494 (13)	−0.0144 (11)	0.0032 (11)	−0.0029 (10)
C9	0.104 (2)	0.101 (2)	0.0500 (15)	−0.0386 (19)	−0.0048 (14)	−0.0093 (15)
N1	0.0533 (10)	0.0370 (10)	0.0479 (11)	−0.0050 (8)	−0.0044 (8)	−0.0040 (8)
O1	0.1135 (15)	0.0386 (10)	0.0600 (11)	−0.0033 (9)	0.0023 (10)	0.0007 (8)
O2	0.1088 (14)	0.0453 (10)	0.0434 (10)	−0.0087 (9)	0.0013 (9)	−0.0001 (7)

Geometric parameters (Å, º) top

C10—C2	1.500 (3)	C4—C8	1.498 (3)
C10—H10A	0.9600	C5—O1	1.211 (3)
C10—H10B	0.9600	C5—O2	1.331 (3)
C10—H10C	0.9600	C6—C7	1.428 (5)
C11—O3	1.197 (3)	C6—O2	1.447 (3)
C11—O4	1.330 (3)	C6—H6A	0.9700
C11—C3	1.463 (3)	C6—H6B	0.9700
C12—O4	1.436 (3)	C7—H7A	0.9600
C12—H12A	0.9600	C7—H7B	0.9600
C12—H12B	0.9600	C7—H7C	0.9600
C12—H12C	0.9600	C8—C9	1.491 (4)
C1—N1	1.380 (3)	C8—H8A	0.9700
C1—C2	1.381 (3)	C8—H8B	0.9700
C1—C5	1.451 (3)	C9—H9A	0.9600
C2—C3	1.422 (3)	C9—H9B	0.9600
C3—C4	1.401 (3)	C9—H9C	0.9600
C4—N1	1.335 (3)	N1—H1A	0.839 (10)

C2—C10—H10A	109.5	O2—C5—C1	113.5 (2)
C2—C10—H10B	109.5	C7—C6—O2	108.8 (3)
H10A—C10—H10B	109.5	C7—C6—H6A	109.9
C2—C10—H10C	109.5	O2—C6—H6A	109.9
H10A—C10—H10C	109.5	C7—C6—H6B	109.9
H10B—C10—H10C	109.5	O2—C6—H6B	109.9
O3—C11—O4	121.4 (2)	H6A—C6—H6B	108.3
O3—C11—C3	126.0 (2)	C6—C7—H7A	109.5
O4—C11—C3	112.6 (2)	C6—C7—H7B	109.5
O4—C12—H12A	109.5	H7A—C7—H7B	109.5
O4—C12—H12B	109.5	C6—C7—H7C	109.5
H12A—C12—H12B	109.5	H7A—C7—H7C	109.5
O4—C12—H12C	109.5	H7B—C7—H7C	109.5
H12A—C12—H12C	109.5	C9—C8—C4	113.3 (2)
H12B—C12—H12C	109.5	C9—C8—H8A	108.9
C11—O4—C12	117.6 (2)	C4—C8—H8A	108.9
N1—C1—C2	108.30 (19)	C9—C8—H8B	108.9
N1—C1—C5	117.4 (2)	C4—C8—H8B	108.9
C2—C1—C5	134.3 (2)	H8A—C8—H8B	107.7
C1—C2—C3	105.90 (18)	C8—C9—H9A	109.5
C1—C2—C10	126.4 (2)	C8—C9—H9B	109.5
C3—C2—C10	127.7 (2)	H9A—C9—H9B	109.5
C4—C3—C2	107.89 (19)	C8—C9—H9C	109.5
C4—C3—C11	122.8 (2)	H9A—C9—H9C	109.5
C2—C3—C11	129.3 (2)	H9B—C9—H9C	109.5
N1—C4—C3	107.36 (19)	C4—N1—C1	110.53 (19)
N1—C4—C8	121.0 (2)	C4—N1—H1A	125.5 (17)
C3—C4—C8	131.6 (2)	C1—N1—H1A	124.0 (17)
O1—C5—O2	122.4 (2)	C5—O2—C6	117.1 (2)
O1—C5—C1	124.1 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ⁱ	0.84 (1)	2.07 (1)	2.883 (3)	165 (2)

Symmetry code: (i) −x, −y+1, −z.

Experimental details

Crystal data
Chemical formula	C₁₂H₁₇NO₄
M_r	239.27
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.2827 (10), 8.8573 (12), 11.1806 (16)
α, β, γ (°)	77.948 (2), 73.135 (2), 69.970 (2)
V (Å³)	643.62 (15)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.15 × 0.12 × 0.06

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.986, 0.995
No. of measured, independent and observed [I > 2σ(I)] reflections	3249, 2255, 1891
R_int	0.018
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.067, 0.220, 1.11
No. of reflections	2255
No. of parameters	159
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.51, −0.36

Computer programs: APEX2 (Bruker, 2004), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ⁱ	0.839 (10)	2.065 (12)	2.883 (3)	165 (2)

Symmetry code: (i) −x, −y+1, −z.

Acknowledgements

The project was supported by the Natural Science Foundation of China (No. 21001054) and the Jiangsu Higher Education Institutions (No. 10KJB150003). The Foundation of UJS (Nos. 09JDG055 and 1143002064) is also gratefully acknowledged.

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