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The title compound, C10H11NO5, belongs to a broad class of nitro­gen heterocycles widely used in medicinal chemistry as well as the pharmaceutical and chemical industries and was selected for crystal structure determination in order to elucidate the conformation of the substituents bonded to the pyrrole ring and the extent of π-electron delocalization. There is structural evidence that both the 2-methoxy­carbonyl and 4-formyl groups interact with the π-cloud of the pyrrole ring. The second methoxy­carbonyl group at N1 is twisted out of the pyrrole plane due to rotations around the methyl­ene bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801005645/bt6023sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801005645/bt6023Isup2.hkl
Contains datablock I

CCDC reference: 165647

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.058
  • wR factor = 0.106
  • Data-to-parameter ratio = 16.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry




Comment top

Polysubstituted and polycondensed pyrrolyl derivatives have found widespread applications as drugs, polymers, dyes, agrochemicals etc. (Gribble, 1996). The title compound, (I), has also been exploited in the synthesis of other heterocyclic derivatives, such as 4-pyrrolyl-1,4-dihydropyridines or glutaric acid derivatives (Milata et al., 2001), which are of interest because of their calcium channel blocking activity. The present crystal structure determination was undertaken in order to establish the conformation of the substituents bonded to the pyrrole ring and the degree of π-electron conjugation.

A drawing of the molecule is shown in Fig. 1. As expected, the central pyrrole ring is planar within experimental error (r.m.s. deviation 0.003 Å). The distortion of the pyrrole ring from C2v symmetry is considerable and concerns mainly the two N—C bonds which differ by a highly significant amount of 18σ. The 2-methoxycarbonyl group (at C5) is roughly coplanar with the mean plane of the pyrrole ring [dihedral angle 7.0 (2)°]; similarly, the formyl group lies exactly in the pyrrole plane [torsion angle C4—C3—C11—O12 = -0.4 (4)°]. Furthermore, the C3—C11 and C5—C13 bond distances of 1.434 (3) and 1.449 (3) Å, respectively, are significantly shorter than the value of 1.487 (5) Å reported for a Csp2—Csp2 single bond (Shmueli et al., 1973). These results indicate that there is some degree of π-electron delocalization from the heterocyclic ring into the C11—O12 and C13—O14 carbonyl bonds. As revealed by the Cambridge Structural Database (Allen & Kennard, 1993), similar features have also been observed for compounds having electron-withdrawing substituents in the 2- and/or 4-positions of the pyrrole ring. The second methoxycarbonyl group of the molecule is rotated around the N1—C6 and C6—C7 bonds [torsion angles C5—N1—C6—C7 = 79.5 (3)° and N1—C6—C7—O8 = -3.7 (3)°], so that it makes an angle of 76.5 (3)° with the pyrrole plane.

As the molecule has no potential hydrohen-bond donor, the packing is governed by van der Waals interactions.

Experimental top

The title compound was prepared by a two-step reaction. In the first step, to a stirred solution of methyl 2-pyrrolylcarbocylate (0.1 mol) in CH2Cl2 (300 ml), CH3NO2 (20 ml) and AlCl3 (30 g) was added dropwise a solution of 1,1-dichloromethyl methyl ether in CH2Cl2 (150 ml) at 273 K. After 1 h, the reaction mixture was poured onto ice/water, extracted with chloroform, dried with sodium sulfate, evaporated to dryness and recrystallized from CCl4. To a stirred solution of methyl 4-formylpyrrolyl-2-carboxylate (50 mmol) obtained above in 20 ml of dimethylformamide (DMF) was added potassium tert-butoxide (55 mmol) and tetrabutylammonium bromide (5 mmol) in 20 ml of DMF at 313 K. After 3 h a solution of alkyl bromoacetate (60 mmol) in 20 ml of DMF was added dropwise and stirred for 3 h. The DMF was evaporated, the residue dissolved in 80 ml of H2O, neutralized with concentrated hydrochloric acid and extracted with chloroform. The extract was dried with Na2SO4 and crystallized from toluene-0cyclohexane (m.p. 343–345 K).

Refinement top

Although the H atoms were seen in a difference Fourier map, they were refined with fixed geometry, riding on their carrier atoms, with Uiso set to 1.2 (or 1.5 for the methyl H atoms) times Ueq of the parent atom. Both methyl groups were allowed to rotate about their local threefold axis.

Computing details top

Data collection: Syntex Software (Syntex, 1973); cell refinement: Syntex Software; data reduction: XP21 (Pavelčík, 1987); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1990); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. View of a molecule of the title compound with its numbering scheme. Displacement ellipsoids are shown at the 35% probability level and H atoms are drawn as spheres of arbitrary radii.
Methyl (4-formyl-2-methoxycarbonyl-1-pyrrolyl)acetate top
Crystal data top
C10H11NO5Dx = 1.395 Mg m3
Dm = 1.39 (1) Mg m3
Dm measured by flotation in bromoform/methanol
Mr = 225.20Melting point: 344 K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 5.101 (1) ÅCell parameters from 15 reflections
b = 20.098 (4) Åθ = 7–18°
c = 10.461 (2) ŵ = 0.11 mm1
β = 90.31 (3)°T = 293 K
V = 1072.4 (4) Å3Prism, light yellow
Z = 40.35 × 0.28 × 0.25 mm
F(000) = 472
Data collection top
Syntex P21
diffractometer
Rint = 0.038
Radiation source: fine-focus sealed tubeθmax = 27.6°, θmin = 2.0°
Graphite monochromatorh = 06
θ/2θ scansk = 026
2623 measured reflectionsl = 1313
2485 independent reflections2 standard reflections every 98 reflections
1469 reflections with I > 2σ(I) intensity decay: 2%
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.058 w = 1/[σ2(Fo2) + (0.0356P)2 + 0.4874P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.106(Δ/σ)max = 0.002
S = 1.04Δρmax = 0.13 e Å3
2485 reflectionsΔρmin = 0.18 e Å3
147 parameters
Crystal data top
C10H11NO5V = 1072.4 (4) Å3
Mr = 225.20Z = 4
Monoclinic, P21/cMo Kα radiation
a = 5.101 (1) ŵ = 0.11 mm1
b = 20.098 (4) ÅT = 293 K
c = 10.461 (2) Å0.35 × 0.28 × 0.25 mm
β = 90.31 (3)°
Data collection top
Syntex P21
diffractometer
Rint = 0.038
2623 measured reflections2 standard reflections every 98 reflections
2485 independent reflections intensity decay: 2%
1469 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0580 restraints
wR(F2) = 0.106H-atom parameters constrained
S = 1.04Δρmax = 0.13 e Å3
2485 reflectionsΔρmin = 0.18 e Å3
147 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.2943 (3)0.12052 (8)0.80735 (14)0.0450 (4)
C20.1398 (4)0.16218 (10)0.74159 (19)0.0498 (5)
H20.00920.18880.77650.060*
C30.2043 (4)0.15949 (10)0.61475 (19)0.0477 (5)
C40.4091 (4)0.11323 (10)0.60355 (18)0.0479 (5)
H40.49220.10070.52840.057*
C50.4638 (4)0.09007 (10)0.72282 (19)0.0448 (5)
C60.2765 (4)0.11229 (11)0.94437 (17)0.0497 (5)
H6A0.29530.06550.96550.060*
H6B0.10490.12670.97270.060*
C70.4831 (4)0.15139 (10)1.01312 (18)0.0460 (5)
O80.6520 (3)0.18302 (8)0.96487 (14)0.0616 (4)
O90.4461 (3)0.14596 (9)1.13692 (13)0.0720 (5)
C100.6268 (5)0.18183 (15)1.2185 (2)0.0805 (8)
H10A0.80340.17041.19620.121*
H10B0.59580.17011.30610.121*
H10C0.60120.22881.20740.121*
C110.0775 (5)0.19716 (12)0.5157 (2)0.0635 (6)
H110.05670.22560.54030.076*
O120.1289 (4)0.19528 (9)0.40404 (15)0.0766 (5)
C130.6579 (4)0.04184 (10)0.7639 (2)0.0520 (5)
O140.7106 (3)0.02797 (8)0.87220 (16)0.0720 (5)
O150.7758 (3)0.01473 (8)0.66302 (16)0.0695 (5)
C160.9699 (5)0.03517 (12)0.6895 (3)0.0785 (8)
H16A1.07050.02240.76330.118*
H16B1.08410.03950.61730.118*
H16C0.88500.07700.70550.118*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0446 (9)0.0509 (10)0.0394 (9)0.0022 (8)0.0019 (7)0.0001 (7)
C20.0488 (12)0.0506 (12)0.0501 (12)0.0033 (10)0.0034 (9)0.0049 (10)
C30.0530 (12)0.0467 (11)0.0433 (11)0.0024 (10)0.0056 (9)0.0018 (9)
C40.0530 (12)0.0497 (12)0.0411 (11)0.0004 (10)0.0021 (9)0.0012 (9)
C50.0442 (11)0.0437 (11)0.0464 (11)0.0007 (9)0.0002 (9)0.0031 (9)
C60.0500 (12)0.0583 (13)0.0407 (10)0.0067 (10)0.0018 (9)0.0002 (10)
C70.0465 (11)0.0538 (12)0.0378 (11)0.0054 (10)0.0012 (9)0.0002 (9)
O80.0600 (9)0.0771 (11)0.0477 (8)0.0199 (9)0.0024 (7)0.0042 (8)
O90.0738 (11)0.1043 (14)0.0378 (8)0.0282 (10)0.0023 (7)0.0020 (8)
C100.0829 (18)0.117 (2)0.0412 (12)0.0255 (17)0.0112 (12)0.0085 (14)
C110.0726 (16)0.0617 (15)0.0562 (15)0.0090 (12)0.0072 (12)0.0002 (11)
O120.0946 (13)0.0822 (13)0.0529 (10)0.0120 (10)0.0073 (9)0.0122 (9)
C130.0526 (12)0.0434 (11)0.0601 (14)0.0018 (10)0.0019 (11)0.0037 (10)
O140.0794 (12)0.0724 (11)0.0640 (10)0.0169 (9)0.0072 (9)0.0138 (9)
O150.0736 (11)0.0632 (10)0.0717 (11)0.0216 (9)0.0060 (9)0.0035 (8)
C160.0670 (16)0.0527 (14)0.116 (2)0.0178 (13)0.0104 (15)0.0018 (15)
Geometric parameters (Å, º) top
N1—C21.338 (3)C7—O91.314 (2)
N1—C51.383 (2)O9—C101.446 (3)
N1—C61.446 (2)C10—H10A0.9600
C2—C31.370 (3)C10—H10B0.9600
C2—H20.9300C10—H10C0.9600
C3—C41.404 (3)C11—O121.199 (3)
C3—C111.434 (3)C11—H110.9300
C4—C51.359 (3)C13—O141.196 (3)
C4—H40.9300C13—O151.334 (3)
C5—C131.449 (3)O15—C161.435 (3)
C6—C71.496 (3)C16—H16A0.9600
C6—H6A0.9700C16—H16B0.9600
C6—H6B0.9700C16—H16C0.9600
C7—O81.186 (2)
C2—N1—C5108.48 (16)O8—C7—C6126.07 (18)
C2—N1—C6122.77 (17)O9—C7—C6109.00 (18)
C5—N1—C6128.75 (17)C7—O9—C10116.48 (18)
N1—C2—C3109.23 (19)O9—C10—H10A109.5
N1—C2—H2125.4O9—C10—H10B109.5
C3—C2—H2125.4H10A—C10—H10B109.5
C2—C3—C4106.84 (18)O9—C10—H10C109.5
C2—C3—C11124.7 (2)H10A—C10—H10C109.5
C4—C3—C11128.47 (19)H10B—C10—H10C109.5
C5—C4—C3107.42 (18)O12—C11—C3125.9 (2)
C5—C4—H4126.3O12—C11—H11117.0
C3—C4—H4126.3C3—C11—H11117.0
C4—C5—N1108.03 (17)O14—C13—O15123.6 (2)
C4—C5—C13129.62 (19)O14—C13—C5125.9 (2)
N1—C5—C13122.35 (18)O15—C13—C5110.44 (18)
N1—C6—C7111.62 (16)C13—O15—C16116.53 (19)
N1—C6—H6A109.3O15—C16—H16A109.5
C7—C6—H6A109.3O15—C16—H16B109.5
N1—C6—H6B109.3H16A—C16—H16B109.5
C7—C6—H6B109.3O15—C16—H16C109.5
H6A—C6—H6B108.0H16A—C16—H16C109.5
O8—C7—O9124.9 (2)H16B—C16—H16C109.5
C5—N1—C2—C30.2 (2)C5—N1—C6—C779.5 (3)
C6—N1—C2—C3179.49 (17)N1—C6—C7—O83.7 (3)
N1—C2—C3—C40.2 (2)N1—C6—C7—O9175.49 (17)
N1—C2—C3—C11179.4 (2)O8—C7—O9—C100.2 (3)
C2—C3—C4—C50.6 (2)C6—C7—O9—C10179.0 (2)
C11—C3—C4—C5179.8 (2)C2—C3—C11—O12179.4 (2)
C3—C4—C5—N10.7 (2)C4—C3—C11—O120.4 (4)
C3—C4—C5—C13179.9 (2)C4—C5—C13—O14173.1 (2)
C2—N1—C5—C40.6 (2)N1—C5—C13—O147.6 (3)
C6—N1—C5—C4179.83 (18)C4—C5—C13—O156.1 (3)
C2—N1—C5—C13179.96 (19)N1—C5—C13—O15173.20 (18)
C6—N1—C5—C130.7 (3)O14—C13—O15—C162.0 (3)
C2—N1—C6—C799.6 (2)C5—C13—O15—C16178.76 (19)

Experimental details

Crystal data
Chemical formulaC10H11NO5
Mr225.20
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)5.101 (1), 20.098 (4), 10.461 (2)
β (°) 90.31 (3)
V3)1072.4 (4)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.35 × 0.28 × 0.25
Data collection
DiffractometerSyntex P21
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2623, 2485, 1469
Rint0.038
(sin θ/λ)max1)0.651
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.058, 0.106, 1.04
No. of reflections2485
No. of parameters147
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.13, 0.18

Computer programs: Syntex Software (Syntex, 1973), Syntex Software, XP21 (Pavelčík, 1987), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1990), SHELXL97.

Selected geometric parameters (Å, º) top
N1—C21.338 (3)C3—C111.434 (3)
N1—C51.383 (2)C4—C51.359 (3)
N1—C61.446 (2)C5—C131.449 (3)
C2—C31.370 (3)C11—O121.199 (3)
C3—C41.404 (3)C13—O141.196 (3)
C2—N1—C5108.48 (16)C4—C3—C11128.47 (19)
C2—N1—C6122.77 (17)C5—C4—C3107.42 (18)
C5—N1—C6128.75 (17)C4—C5—N1108.03 (17)
N1—C2—C3109.23 (19)C4—C5—C13129.62 (19)
C2—C3—C4106.84 (18)N1—C5—C13122.35 (18)
C2—C3—C11124.7 (2)
C5—N1—C6—C779.5 (3)C4—C3—C11—O120.4 (4)
N1—C6—C7—O83.7 (3)N1—C5—C13—O147.6 (3)
 

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