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The crystal and molecular structure of the title compound, C11H18NO3, has been determined from X-ray diffraction data. The compound crystallizes in the centrosymmetric space group Pnma. The main part of the mol­ecule lies at a special position on the mirror plane.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536800019334/na6018sup1.cif
Contains datablocks TOZ, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536800019334/na6018Isup2.hkl
Contains datablock I

CCDC reference: 155901

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.044
  • wR factor = 0.152
  • Data-to-parameter ratio = 11.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_030 Alert C Refined Extinction parameter within range .... 3.00 Sigma
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

The title molecule, (I), and the labeling scheme are shown in Fig. 1. As expected, the part of the molecule containing the pyrrol ring with the ethoxycarbonyl group is planar with standard bond distances and angles similar to that in hexa-2,4-diyne-6-(2,2,5,5-tetramethyl-1-oxyl-3-pyrrolin-3-carboxylate)-1-ol (Wiley, 1991). Two atoms, C12 and O6, showed higher values of atomic displacement parameters perpendicular to the plane of molecule, i.e. ellipsoids are prolonged along the b axis direction. In contrast (Wiley, 1991), there are no hydrogen bonds because of a lack of donor atoms. The packing diagram of the structure is presented in Fig. 2.

Experimental top

A solution of 3-carboxy-2,2,5,5-tetramethyl-1H-2,5-dihydropyrrol-1-yloxyl (1.84 g, 0.01 mol), dicyclohexylcarbodiimide (2.1 g, 0.01 mol), ethanol (1 g, 0.022 mol) and 4-(pyrrol-1-yl)pyridine (0.1 g) in 20 ml dichloromethane was stirred overnight. After filtering off the dicyclohexylurea, the solution was extracted with 5% solution of sodium hydrogencarbonate and dried with magnesium sulfate. The methylene chloride was evaporated and the crude product was crystallized from hexane solution.

Refinement top

Two reflections 011 and 101 were omitted from the final refinement due to the large beam stop used. The systematic absences showed two possible space groups, non-centrosymmetric Pn21a and centrosymmetric Pnma. The phase problem was solved in the space group Pnma. All H atoms were found in the difference Fourier maps and freely refined with isotropic displacement parameters. The refinement in non-centrosymetric Pn21a led to lowering the R value from 0.044 to 0.042. However, the refinement in this space group was less stable and led to unrealistic positions of H atoms. Free refinement in Pnma gave C—H bond distances in the interval 0.96–1.03 Å and free refinement in Pn21a gave deviations of non-H atoms from planarity less than 2 s.u.'s and C—H bonds in the range 0.85–1.35 Å. Therefore, the Pnma group was prefered.

Computing details top

Data collection: COLLECT (Hooft, 1998) and DENZO (Otwinowski, 1997); cell refinement: COLLECT and DENZO; data reduction: COLLECT and DENZO; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and ORTEP-3.

Figures top
[Figure 1] Fig. 1. The structure of the title compound showing the atom-numbering scheme. Displacement ellipsoids of the non-H atoms are drawn at the 50% probability level.
[Figure 2] Fig. 2. A PICTUR (Dusek, 1994) diagram showing the crystal packing of the title compound viewed along the b axis.
3-ethoxycarbonyl- 2,2,5,5-tetramethyl-1H-2,5-dihydropyrrol-1-yloxyl top
Crystal data top
C11H18NO3Dx = 1.164 Mg m3
Mr = 212.26Melting point: 105-107 C K
Orthorhombic, PnmaMo Kα radiation, λ = 0.71070 Å
a = 10.4710 (4) ÅCell parameters from 12475 reflections
b = 9.3700 (3) Åθ = 1.0–27.5°
c = 12.3500 (4) ŵ = 0.08 mm1
V = 1211.70 (7) Å3T = 150 K
Z = 4Prism, yellow
F(000) = 4600.4 × 0.3 × 0.2 mm
Data collection top
Nonius KappaCCD area-detector
diffractometer
1216 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.028
Graphite monochromatorθmax = 27.5°, θmin = 3.3°
ϕ and ω scansh = 1313
15701 measured reflectionsk = 1212
1464 independent reflectionsl = 1516
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.044H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.152 w = 1/[σ2(Fo2) + (0.1P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.22(Δ/σ)max = 0.009
1462 reflectionsΔρmax = 0.27 e Å3
123 parametersΔρmin = 0.15 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.00003 (1)
Crystal data top
C11H18NO3V = 1211.70 (7) Å3
Mr = 212.26Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 10.4710 (4) ŵ = 0.08 mm1
b = 9.3700 (3) ÅT = 150 K
c = 12.3500 (4) Å0.4 × 0.3 × 0.2 mm
Data collection top
Nonius KappaCCD area-detector
diffractometer
1216 reflections with I > 2σ(I)
15701 measured reflectionsRint = 0.028
1464 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.152H atoms treated by a mixture of independent and constrained refinement
S = 1.22Δρmax = 0.27 e Å3
1462 reflectionsΔρmin = 0.15 e Å3
123 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. Two strong reflections 101 and 011 were omitted from the final refinement due inaccuracy in measurement.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.18529 (12)0.25000.62264 (11)0.0421 (4)
C20.14572 (14)0.25000.50795 (12)0.0331 (4)
C30.00289 (14)0.25000.52252 (11)0.0308 (4)
C40.03176 (14)0.25000.62623 (11)0.0326 (4)
C50.07972 (13)0.25000.70199 (13)0.0340 (4)
O60.30192 (11)0.25000.65080 (11)0.0662 (5)
C70.19680 (13)0.11609 (12)0.45207 (11)0.0462 (4)
C80.08547 (15)0.25000.42918 (12)0.0346 (4)
O90.05073 (12)0.25000.33631 (10)0.0522 (4)
O100.20763 (11)0.25000.45910 (8)0.0403 (4)
C110.30171 (17)0.25000.37204 (15)0.0532 (5)
C120.4288 (2)0.25000.4199 (2)0.0906 (10)
C130.08471 (13)0.3840 (1)0.77207 (10)0.0426 (4)
H10.1239 (17)0.25000.6551 (15)0.044 (5)*
H20.0108 (13)0.3868 (13)0.8198 (12)0.051 (3)*
H30.0784 (12)0.4699 (17)0.7274 (11)0.054 (4)*
H40.2888 (15)0.1179 (15)0.4577 (10)0.050 (4)*
H50.1663 (14)0.3828 (15)0.8143 (14)0.059 (4)*
H60.1693 (13)0.1170 (16)0.3737 (13)0.060 (4)*
H70.1639 (12)0.0314 (17)0.4861 (12)0.052 (3)*
H80.492 (2)0.25000.358 (2)0.083 (8)*
H90.2852 (16)0.162 (2)0.3302 (15)0.081 (5)*
H100.446 (2)0.179 (3)0.475 (2)0.138 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0289 (7)0.0623 (9)0.0350 (8)0.0000.0006 (5)0.000
C20.0346 (8)0.0341 (7)0.0306 (8)0.0000.0039 (6)0.000
C30.0378 (8)0.0259 (7)0.0287 (9)0.0000.0010 (5)0.000
C40.0319 (8)0.0368 (7)0.0291 (8)0.0000.0016 (6)0.000
C50.0313 (7)0.0412 (8)0.0295 (8)0.0000.0004 (6)0.000
O60.0269 (7)0.1213 (13)0.0503 (9)0.0000.0041 (5)0.000
C70.0480 (8)0.0370 (7)0.0536 (8)0.0059 (5)0.0075 (6)0.0039 (5)
C80.0441 (9)0.0310 (7)0.0287 (8)0.0000.0033 (6)0.000
O90.0583 (8)0.0714 (8)0.0268 (7)0.0000.0008 (5)0.000
O100.0392 (7)0.0527 (7)0.0288 (6)0.0000.0099 (4)0.000
C110.0478 (11)0.0773 (14)0.0343 (10)0.0000.0155 (7)0.000
C120.0468 (12)0.183 (3)0.0422 (13)0.0000.0162 (10)0.000
C130.0462 (7)0.0436 (7)0.0380 (7)0.0028 (5)0.0054 (5)0.0039 (5)
Geometric parameters (Å, º) top
N1—O61.270 (2)C7—H61.01 (2)
N1—C51.477 (2)C7—H70.96 (2)
N1—C21.476 (2)C8—O91.203 (2)
C2—C31.506 (2)C8—O101.331 (2)
C2—C71.529 (1)O10—C111.458 (2)
C2—C7i1.529 (1)C11—C121.456 (3)
C3—C41.331 (2)C11—H90.99 (2)
C3—C81.478 (2)C12—H81.01 (3)
C4—C51.496 (2)C12—H100.97 (3)
C4—H11.029 (18)C13—H20.97 (2)
C5—C13i1.526 (1)C13—H30.98 (1)
C5—C131.526 (1)C13—H51.00 (2)
C7—H40.97 (2)
O6—N1—C5122.5 (1)C2—C7—H6109.0 (9)
O6—N1—C2122.2 (1)H4—C7—H6111 (1)
C5—N1—C2115.2 (1)C2—C7—H7110.8 (9)
N1—C2—C399.4 (1)H4—C7—H7110 (1)
N1—C2—C7109.58 (9)H6—C7—H7109 (1)
C3—C2—C7113.66 (8)O9—C8—O10123.7 (1)
N1—C2—C7i109.57 (9)O9—C8—C3123.6 (1)
C3—C2—C7i113.66 (8)O10—C8—C3112.6 (1)
C7—C2—C7i110.3 (1)C8—O10—C11116.4 (1)
C4—C3—C8125.4 (1)O10—C11—C12108.5 (2)
C4—C3—C2112.7 (1)O10—C11—H9106 (1)
C8—C3—C2121.9 (1)C12—C11—H9112 (1)
C3—C4—C5112.9 (1)C11—C12—H8108 (2)
C3—C4—H1126 (1)C11—C12—H10118 (2)
C5—C4—H1121 (1)H8—C12—H10114 (2)
N1—C5—C499.7 (1)C5—C13—H2109.8 (7)
N1—C5—C13i110.53 (8)C5—C13—H3110.8 (8)
C4—C5—C13i112.42 (8)H2—C13—H3105 (1)
N1—C5—C13110.53 (8)C5—C13—H5108.4 (8)
C4—C5—C13112.42 (8)H2—C13—H5111 (1)
C13i—C5—C13110.7 (1)H3—C13—H5111 (1)
C2—C7—H4107.6 (8)
Symmetry code: (i) x, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC11H18NO3
Mr212.26
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)150
a, b, c (Å)10.4710 (4), 9.3700 (3), 12.3500 (4)
V3)1211.70 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.4 × 0.3 × 0.2
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
15701, 1464, 1216
Rint0.028
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.152, 1.22
No. of reflections1462
No. of parameters123
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.27, 0.15

Computer programs: COLLECT (Hooft, 1998) and DENZO (Otwinowski, 1997), COLLECT and DENZO, SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), SHELXL97 and ORTEP-3.

Selected geometric parameters (Å, º) top
N1—O61.270 (2)C4—C51.496 (2)
N1—C51.477 (2)C5—C131.526 (1)
N1—C21.476 (2)C8—O91.203 (2)
C2—C31.506 (2)C8—O101.331 (2)
C2—C71.529 (1)O10—C111.458 (2)
C3—C41.331 (2)C11—C121.456 (3)
C3—C81.478 (2)
O6—N1—C5122.5 (1)N1—C5—C499.7 (1)
C5—N1—C2115.2 (1)N1—C5—C13110.53 (8)
N1—C2—C399.4 (1)C4—C5—C13112.42 (8)
N1—C2—C7109.58 (9)C13i—C5—C13110.7 (1)
C3—C2—C7113.66 (8)O9—C8—O10123.7 (1)
C7—C2—C7i110.3 (1)O9—C8—C3123.6 (1)
C4—C3—C8125.4 (1)O10—C8—C3112.6 (1)
C4—C3—C2112.7 (1)C8—O10—C11116.4 (1)
C3—C4—C5112.9 (1)O10—C11—C12108.5 (2)
Symmetry code: (i) x, y+1/2, z.
 

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