In the title cycloadduct, C
20H
19N
3O
3, the molecules form centrosymmetric dimers linked by N—H
O hydrogen bonds, forming an
R22(8) ring. The overall conformation of the pyrrolizidine nucleus is folded about the bridging bond.
Supporting information
CCDC reference: 287477
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.002 Å
- R factor = 0.053
- wR factor = 0.164
- Data-to-parameter ratio = 16.7
checkCIF/PLATON results
No syntax errors found
Alert level B
PLAT241_ALERT_2_B Check High Ueq as Compared to Neighbors for C6
PLAT430_ALERT_2_B Short Inter D...A Contact O2 .. O3 .. 2.81 Ang.
Alert level C
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature 293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature . 293 K
PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 2.75 Ratio
PLAT230_ALERT_2_C Hirshfeld Test Diff for N23 - C4 .. 5.57 su
PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for C8
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for N23
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C7
0 ALERT level A = In general: serious problem
2 ALERT level B = Potentially serious problem
7 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
7 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
A mixture of nitrostyrene (1 mmol), isatin (1 mmol) and proline (1 mmol) in methanol (20 ml) was refluxed until the disappearance of starting materials. After completion of the reaction, the reaction mixture was concentrated in vacuo and the residue was subjected to column chromatography with a hexane–ethyl acetate mixture (8:2) in order to get the pure cycloadduct. Crystals suitable for sigle-crystal X-ray diffraction were grown by slow evaporation of a methanol solution.
H atoms were positioned geometrically and treated as riding on their parent atoms with aromatic C—H distances in the range 0.93–0.97 Å and an N—H distance of 0.86 Å, and with Uiso(H) = 1.5Ueq(C) for methyl H and 1.2Ueq(N,C) for other H atoms.
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PARST (Nardelli, 1995).
1'-nitro-2'-phenyl-2',3',4',5',6',7'-hexahydro-1
H-indole- 3-spiro-3'-1'H-pyrrolizin-2(3
H)-one
top
Crystal data top
C20H19N3O3 | F(000) = 1472 |
Mr = 349.38 | Dx = 1.372 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 7483 reflections |
a = 23.8981 (15) Å | θ = 2.5–26.5° |
b = 7.5886 (4) Å | µ = 0.09 mm−1 |
c = 19.137 (1) Å | T = 293 K |
β = 102.941 (2)° | Block, colourless |
V = 3382.4 (3) Å3 | 0.23 × 0.21 × 0.20 mm |
Z = 8 | |
Data collection top
CCD Area Detector diffractometer | 3373 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.018 |
Graphite monochromator | θmax = 28.0°, θmin = 2.2° |
ω scans | h = −30→31 |
13982 measured reflections | k = −9→9 |
3921 independent reflections | l = −25→25 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.053 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.164 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0985P)2 + 1.7117P] where P = (Fo2 + 2Fc2)/3 |
3921 reflections | (Δ/σ)max < 0.001 |
235 parameters | Δρmax = 0.29 e Å−3 |
0 restraints | Δρmin = −0.29 e Å−3 |
Crystal data top
C20H19N3O3 | V = 3382.4 (3) Å3 |
Mr = 349.38 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 23.8981 (15) Å | µ = 0.09 mm−1 |
b = 7.5886 (4) Å | T = 293 K |
c = 19.137 (1) Å | 0.23 × 0.21 × 0.20 mm |
β = 102.941 (2)° | |
Data collection top
CCD Area Detector diffractometer | 3373 reflections with I > 2σ(I) |
13982 measured reflections | Rint = 0.018 |
3921 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.053 | 0 restraints |
wR(F2) = 0.164 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.29 e Å−3 |
3921 reflections | Δρmin = −0.29 e Å−3 |
235 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 | Uiso*/Ueq | |
O1 | 0.07159 (5) | −0.02311 (14) | 0.06395 (6) | 0.0512 (3) | |
O2 | 0.27239 (8) | 0.0114 (4) | 0.18077 (14) | 0.1251 (9) | |
O3 | 0.25603 (8) | 0.2023 (3) | 0.25370 (12) | 0.1132 (7) | |
N1 | 0.08805 (5) | 0.10616 (17) | 0.21380 (6) | 0.0436 (3) | |
N10 | 0.00611 (5) | 0.20074 (17) | 0.05533 (7) | 0.0445 (3) | |
H10 | −0.0198 | 0.1601 | 0.0204 | 0.053* | |
N23 | 0.23993 (6) | 0.0986 (2) | 0.20513 (10) | 0.0650 (5) | |
C2 | 0.08624 (6) | 0.22227 (18) | 0.15167 (7) | 0.0371 (3) | |
C3 | 0.15020 (5) | 0.26078 (18) | 0.15331 (7) | 0.0367 (3) | |
H3 | 0.1640 | 0.3385 | 0.1945 | 0.044* | |
C4 | 0.17707 (6) | 0.0804 (2) | 0.17411 (8) | 0.0440 (3) | |
H4 | 0.1718 | 0.0078 | 0.1308 | 0.053* | |
C5 | 0.14116 (7) | −0.0006 (2) | 0.22439 (10) | 0.0518 (4) | |
H5 | 0.1307 | −0.1215 | 0.2087 | 0.062* | |
C6 | 0.16539 (11) | −0.0018 (5) | 0.30496 (12) | 0.1010 (10) | |
H6A | 0.1773 | −0.1196 | 0.3216 | 0.121* | |
H6B | 0.1981 | 0.0767 | 0.3177 | 0.121* | |
C7 | 0.11687 (10) | 0.0609 (3) | 0.33690 (11) | 0.0705 (5) | |
H7A | 0.0912 | −0.0352 | 0.3419 | 0.085* | |
H7B | 0.1311 | 0.1152 | 0.3834 | 0.085* | |
C8 | 0.08778 (11) | 0.1922 (3) | 0.28300 (9) | 0.0728 (6) | |
H8A | 0.0489 | 0.2147 | 0.2878 | 0.087* | |
H8B | 0.1088 | 0.3025 | 0.2878 | 0.087* | |
C9 | 0.05515 (6) | 0.11579 (18) | 0.08476 (7) | 0.0397 (3) | |
C11 | 0.00235 (6) | 0.3636 (2) | 0.08866 (8) | 0.0408 (3) | |
C12 | 0.04882 (6) | 0.38338 (18) | 0.14655 (7) | 0.0380 (3) | |
C13 | 0.05582 (7) | 0.5407 (2) | 0.18389 (8) | 0.0467 (4) | |
H13 | 0.0871 | 0.5571 | 0.2222 | 0.056* | |
C14 | 0.01571 (8) | 0.6740 (2) | 0.16365 (9) | 0.0538 (4) | |
H14 | 0.0201 | 0.7803 | 0.1884 | 0.065* | |
C15 | −0.03060 (8) | 0.6494 (2) | 0.10691 (10) | 0.0584 (4) | |
H15 | −0.0574 | 0.7393 | 0.0944 | 0.070* | |
C16 | −0.03812 (7) | 0.4937 (2) | 0.06811 (9) | 0.0535 (4) | |
H16 | −0.0693 | 0.4777 | 0.0297 | 0.064* | |
C17 | 0.16435 (6) | 0.3511 (2) | 0.08923 (7) | 0.0395 (3) | |
C18 | 0.16935 (7) | 0.2624 (2) | 0.02743 (8) | 0.0492 (4) | |
H18 | 0.1631 | 0.1414 | 0.0240 | 0.059* | |
C19 | 0.18361 (8) | 0.3528 (3) | −0.02910 (10) | 0.0614 (5) | |
H19 | 0.1873 | 0.2916 | −0.0699 | 0.074* | |
C20 | 0.19233 (9) | 0.5317 (3) | −0.02532 (11) | 0.0670 (5) | |
H20 | 0.2019 | 0.5914 | −0.0635 | 0.080* | |
C21 | 0.18695 (9) | 0.6217 (3) | 0.03473 (11) | 0.0682 (5) | |
H21 | 0.1925 | 0.7430 | 0.0373 | 0.082* | |
C22 | 0.17320 (8) | 0.5322 (2) | 0.09184 (10) | 0.0532 (4) | |
H22 | 0.1698 | 0.5944 | 0.1326 | 0.064* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0497 (6) | 0.0439 (6) | 0.0534 (6) | 0.0012 (4) | −0.0023 (5) | −0.0150 (5) |
O2 | 0.0705 (11) | 0.176 (2) | 0.1421 (18) | 0.0555 (13) | 0.0530 (12) | 0.0464 (17) |
O3 | 0.0751 (11) | 0.1170 (15) | 0.1170 (15) | −0.0209 (10) | −0.0428 (10) | 0.0099 (13) |
N1 | 0.0408 (6) | 0.0482 (7) | 0.0400 (6) | −0.0025 (5) | 0.0052 (5) | 0.0009 (5) |
N10 | 0.0353 (6) | 0.0497 (7) | 0.0422 (6) | −0.0014 (5) | −0.0046 (5) | −0.0104 (5) |
N23 | 0.0434 (8) | 0.0808 (11) | 0.0687 (10) | 0.0111 (7) | 0.0081 (7) | 0.0333 (9) |
C2 | 0.0340 (6) | 0.0399 (7) | 0.0346 (6) | −0.0027 (5) | 0.0018 (5) | −0.0052 (5) |
C3 | 0.0328 (6) | 0.0391 (7) | 0.0346 (6) | −0.0006 (5) | 0.0000 (5) | −0.0033 (5) |
C4 | 0.0415 (7) | 0.0453 (8) | 0.0422 (7) | 0.0049 (6) | 0.0029 (6) | 0.0008 (6) |
C5 | 0.0523 (9) | 0.0420 (8) | 0.0613 (10) | 0.0029 (6) | 0.0134 (7) | 0.0091 (7) |
C6 | 0.0788 (15) | 0.164 (3) | 0.0608 (13) | 0.0419 (17) | 0.0180 (11) | 0.0545 (16) |
C7 | 0.0788 (13) | 0.0821 (14) | 0.0485 (10) | −0.0018 (11) | 0.0099 (9) | 0.0132 (9) |
C8 | 0.0909 (14) | 0.0873 (14) | 0.0391 (9) | 0.0276 (12) | 0.0122 (9) | 0.0023 (9) |
C9 | 0.0370 (7) | 0.0412 (7) | 0.0379 (7) | −0.0053 (5) | 0.0019 (5) | −0.0049 (5) |
C11 | 0.0344 (6) | 0.0476 (8) | 0.0392 (7) | −0.0008 (5) | 0.0057 (5) | −0.0041 (6) |
C12 | 0.0335 (6) | 0.0420 (7) | 0.0377 (7) | −0.0013 (5) | 0.0061 (5) | −0.0035 (5) |
C13 | 0.0455 (8) | 0.0468 (8) | 0.0455 (8) | −0.0013 (6) | 0.0055 (6) | −0.0093 (6) |
C14 | 0.0574 (9) | 0.0470 (8) | 0.0583 (9) | 0.0045 (7) | 0.0157 (7) | −0.0102 (7) |
C15 | 0.0537 (9) | 0.0587 (10) | 0.0619 (10) | 0.0180 (8) | 0.0112 (8) | −0.0017 (8) |
C16 | 0.0401 (8) | 0.0639 (10) | 0.0520 (9) | 0.0101 (7) | 0.0007 (6) | −0.0043 (7) |
C17 | 0.0300 (6) | 0.0465 (7) | 0.0389 (7) | −0.0005 (5) | 0.0011 (5) | 0.0002 (6) |
C18 | 0.0482 (8) | 0.0521 (9) | 0.0473 (8) | 0.0047 (7) | 0.0107 (6) | −0.0016 (7) |
C19 | 0.0563 (10) | 0.0834 (13) | 0.0472 (9) | 0.0093 (9) | 0.0174 (7) | 0.0014 (9) |
C20 | 0.0586 (11) | 0.0824 (14) | 0.0624 (11) | −0.0048 (9) | 0.0188 (9) | 0.0193 (10) |
C21 | 0.0742 (13) | 0.0576 (10) | 0.0720 (13) | −0.0165 (9) | 0.0145 (10) | 0.0091 (9) |
C22 | 0.0552 (9) | 0.0507 (9) | 0.0514 (9) | −0.0113 (7) | 0.0069 (7) | −0.0031 (7) |
Geometric parameters (Å, º) top
O1—C9 | 1.222 (2) | C7—H7B | 0.9700 |
O2—N23 | 1.191 (3) | C8—H8A | 0.9700 |
O3—N23 | 1.213 (3) | C8—H8B | 0.9700 |
N1—C2 | 1.473 (2) | C11—C16 | 1.376 (2) |
N1—C5 | 1.481 (2) | C11—C12 | 1.3901 (19) |
N1—C8 | 1.478 (2) | C12—C13 | 1.382 (2) |
N10—C9 | 1.346 (2) | C13—C14 | 1.388 (2) |
N10—C11 | 1.403 (2) | C13—H13 | 0.9300 |
N10—H10 | 0.8600 | C14—C15 | 1.379 (3) |
N23—C4 | 1.493 (2) | C14—H14 | 0.9300 |
C2—C12 | 1.5048 (19) | C15—C16 | 1.386 (3) |
C2—C3 | 1.5495 (18) | C15—H15 | 0.9300 |
C2—C9 | 1.5552 (18) | C16—H16 | 0.9300 |
C3—C17 | 1.5081 (19) | C17—C22 | 1.389 (2) |
C3—C4 | 1.526 (2) | C17—C18 | 1.389 (2) |
C3—H3 | 0.9800 | C18—C19 | 1.386 (2) |
C4—C5 | 1.553 (2) | C18—H18 | 0.9300 |
C4—H4 | 0.9800 | C19—C20 | 1.373 (3) |
C5—C6 | 1.521 (3) | C19—H19 | 0.9300 |
C5—H5 | 0.9800 | C20—C21 | 1.367 (3) |
C6—C7 | 1.504 (3) | C20—H20 | 0.9300 |
C6—H6A | 0.9700 | C21—C22 | 1.387 (3) |
C6—H6B | 0.9700 | C21—H21 | 0.9300 |
C7—C8 | 1.490 (3) | C22—H22 | 0.9300 |
C7—H7A | 0.9700 | | |
| | | |
C2—N1—C5 | 107.9 (1) | N1—C8—C7 | 103.28 (17) |
C2—N1—C8 | 117.0 (1) | N1—C8—H8A | 111.1 |
C5—N1—C8 | 107.2 (1) | C7—C8—H8A | 111.1 |
C9—N10—C11 | 111.73 (11) | N1—C8—H8B | 111.1 |
C9—N10—H10 | 124.1 | C7—C8—H8B | 111.1 |
C11—N10—H10 | 124.1 | H8A—C8—H8B | 109.1 |
O2—N23—O3 | 122.5 (2) | O1—C9—N10 | 126.18 (13) |
O2—N23—C4 | 118.6 (2) | O1—C9—C2 | 125.95 (13) |
O3—N23—C4 | 118.86 (18) | N10—C9—C2 | 107.84 (12) |
N1—C2—C12 | 116.64 (11) | C16—C11—C12 | 122.37 (14) |
N1—C2—C3 | 104.23 (10) | C16—C11—N10 | 127.91 (14) |
C12—C2—C3 | 114.65 (11) | C12—C11—N10 | 109.65 (12) |
N1—C2—C9 | 106.03 (11) | C13—C12—C11 | 119.19 (13) |
C12—C2—C9 | 101.61 (11) | C13—C12—C2 | 131.82 (13) |
C3—C2—C9 | 113.70 (11) | C11—C12—C2 | 108.74 (12) |
C17—C3—C4 | 117.51 (12) | C12—C13—C14 | 119.28 (14) |
C17—C3—C2 | 117.97 (11) | C12—C13—H13 | 120.4 |
C4—C3—C2 | 101.06 (11) | C14—C13—H13 | 120.4 |
C17—C3—H3 | 106.5 | C15—C14—C13 | 120.26 (15) |
C4—C3—H3 | 106.5 | C15—C14—H14 | 119.9 |
C2—C3—H3 | 106.5 | C13—C14—H14 | 119.9 |
N23—C4—C3 | 110.38 (13) | C14—C15—C16 | 121.49 (16) |
N23—C4—C5 | 115.90 (13) | C14—C15—H15 | 119.3 |
C3—C4—C5 | 104.96 (12) | C16—C15—H15 | 119.3 |
N23—C4—H4 | 108.5 | C11—C16—C15 | 117.39 (15) |
C3—C4—H4 | 108.5 | C11—C16—H16 | 121.3 |
C5—C4—H4 | 108.5 | C15—C16—H16 | 121.3 |
N1—C5—C6 | 105.19 (15) | C22—C17—C18 | 117.94 (15) |
N1—C5—C4 | 105.90 (12) | C22—C17—C3 | 118.72 (14) |
C6—C5—C4 | 119.52 (17) | C18—C17—C3 | 123.34 (13) |
N1—C5—H5 | 108.6 | C19—C18—C17 | 120.51 (16) |
C6—C5—H5 | 108.6 | C19—C18—H18 | 119.7 |
C4—C5—H5 | 108.6 | C17—C18—H18 | 119.7 |
C7—C6—C5 | 104.89 (18) | C20—C19—C18 | 120.60 (18) |
C7—C6—H6A | 110.8 | C20—C19—H19 | 119.7 |
C5—C6—H6A | 110.8 | C18—C19—H19 | 119.7 |
C7—C6—H6B | 110.8 | C21—C20—C19 | 119.76 (18) |
C5—C6—H6B | 110.8 | C21—C20—H20 | 120.1 |
H6A—C6—H6B | 108.8 | C19—C20—H20 | 120.1 |
C8—C7—C6 | 102.29 (17) | C20—C21—C22 | 120.06 (18) |
C8—C7—H7A | 111.3 | C20—C21—H21 | 120.0 |
C6—C7—H7A | 111.3 | C22—C21—H21 | 120.0 |
C8—C7—H7B | 111.3 | C21—C22—C17 | 121.12 (17) |
C6—C7—H7B | 111.3 | C21—C22—H22 | 119.4 |
H7A—C7—H7B | 109.2 | C17—C22—H22 | 119.4 |
| | | |
C5—N1—C2—C12 | −159.01 (12) | C12—C2—C9—O1 | 175.92 (14) |
C8—N1—C2—C12 | −38.21 (18) | C3—C2—C9—O1 | 52.2 (2) |
C5—N1—C2—C3 | −31.5 (1) | N1—C2—C9—N10 | 116.29 (13) |
C8—N1—C2—C3 | 89.28 (16) | C12—C2—C9—N10 | −6.06 (15) |
C5—N1—C2—C9 | 88.76 (13) | C3—C2—C9—N10 | −129.79 (13) |
C8—N1—C2—C9 | −150.43 (14) | C9—N10—C11—C16 | 172.24 (16) |
N1—C2—C3—C17 | 169.54 (11) | C9—N10—C11—C12 | −4.67 (18) |
C12—C2—C3—C17 | −61.76 (16) | C16—C11—C12—C13 | −1.8 (2) |
C9—C2—C3—C17 | 54.55 (16) | N10—C11—C12—C13 | 175.29 (13) |
N1—C2—C3—C4 | 40.0 (1) | C16—C11—C12—C2 | −176.78 (14) |
C12—C2—C3—C4 | 168.70 (11) | N10—C11—C12—C2 | 0.33 (16) |
C9—C2—C3—C4 | −74.99 (13) | N1—C2—C12—C13 | 74.5 (2) |
O2—N23—C4—C3 | −127.59 (18) | C3—C2—C12—C13 | −47.7 (2) |
O3—N23—C4—C3 | 51.8 (2) | C9—C2—C12—C13 | −170.75 (16) |
O2—N23—C4—C5 | 113.3 (2) | N1—C2—C12—C11 | −111.39 (13) |
O3—N23—C4—C5 | −67.3 (2) | C3—C2—C12—C11 | 126.42 (13) |
C17—C3—C4—N23 | 71.17 (16) | C9—C2—C12—C11 | 3.35 (15) |
C2—C3—C4—N23 | −158.99 (13) | C11—C12—C13—C14 | 1.3 (2) |
C17—C3—C4—C5 | −163.27 (12) | C2—C12—C13—C14 | 174.85 (15) |
C2—C3—C4—C5 | −33.4 (1) | C12—C13—C14—C15 | 0.0 (3) |
C2—N1—C5—C6 | 137.50 (17) | C13—C14—C15—C16 | −0.9 (3) |
C8—N1—C5—C6 | 10.7 (2) | C12—C11—C16—C15 | 1.0 (3) |
C2—N1—C5—C4 | 10.1 (2) | N10—C11—C16—C15 | −175.55 (16) |
C8—N1—C5—C4 | −116.73 (16) | C14—C15—C16—C11 | 0.4 (3) |
N23—C4—C5—N1 | 137.66 (15) | C4—C3—C17—C22 | −140.90 (14) |
C3—C4—C5—N1 | 15.6 (2) | C2—C3—C17—C22 | 97.67 (16) |
N23—C4—C5—C6 | 19.3 (2) | C4—C3—C17—C18 | 38.75 (18) |
C3—C4—C5—C6 | −102.70 (19) | C2—C3—C17—C18 | −82.68 (17) |
N1—C5—C6—C7 | 15.2 (3) | C22—C17—C18—C19 | 1.0 (2) |
C4—C5—C6—C7 | 133.9 (2) | C3—C17—C18—C19 | −178.69 (14) |
C5—C6—C7—C8 | −35.0 (3) | C17—C18—C19—C20 | −0.8 (3) |
C2—N1—C8—C7 | −154.05 (16) | C18—C19—C20—C21 | 0.0 (3) |
C5—N1—C8—C7 | −32.8 (2) | C19—C20—C21—C22 | 0.5 (3) |
C6—C7—C8—N1 | 41.6 (3) | C20—C21—C22—C17 | −0.4 (3) |
C11—N10—C9—O1 | −175.23 (14) | C18—C17—C22—C21 | −0.4 (2) |
C11—N10—C9—C2 | 6.76 (16) | C3—C17—C22—C21 | 179.29 (16) |
N1—C2—C9—O1 | −61.72 (18) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6B···O3 | 0.97 | 2.26 | 3.001 (4) | 133 |
N10—H10···O1i | 0.86 | 2.08 | 2.929 (2) | 169 |
C20—H20···O2ii | 0.93 | 2.58 | 3.285 (3) | 133 |
Symmetry codes: (i) −x, −y, −z; (ii) −x+1/2, −y+1/2, −z. |
Experimental details
Crystal data |
Chemical formula | C20H19N3O3 |
Mr | 349.38 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 293 |
a, b, c (Å) | 23.8981 (15), 7.5886 (4), 19.137 (1) |
β (°) | 102.941 (2) |
V (Å3) | 3382.4 (3) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.23 × 0.21 × 0.20 |
|
Data collection |
Diffractometer | CCD Area Detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13982, 3921, 3373 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.660 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.053, 0.164, 1.03 |
No. of reflections | 3921 |
No. of parameters | 235 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.29, −0.29 |
Selected geometric parameters (Å, º) topO1—C9 | 1.222 (2) | N1—C8 | 1.478 (2) |
O2—N23 | 1.191 (3) | N10—C9 | 1.346 (2) |
O3—N23 | 1.213 (3) | N10—C11 | 1.403 (2) |
N1—C2 | 1.473 (2) | N23—C4 | 1.493 (2) |
N1—C5 | 1.481 (2) | | |
| | | |
C2—N1—C5 | 107.9 (1) | C5—N1—C8 | 107.2 (1) |
C2—N1—C8 | 117.0 (1) | | |
| | | |
C5—N1—C2—C3 | −31.5 (1) | C3—C4—C5—N1 | 15.6 (2) |
N1—C2—C3—C4 | 40.0 (1) | N1—C5—C6—C7 | 15.2 (3) |
C2—C3—C4—C5 | −33.4 (1) | C5—C6—C7—C8 | −35.0 (3) |
C8—N1—C5—C6 | 10.7 (2) | C5—N1—C8—C7 | −32.8 (2) |
C2—N1—C5—C4 | 10.1 (2) | C6—C7—C8—N1 | 41.6 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6B···O3 | 0.97 | 2.26 | 3.001 (4) | 133 |
N10—H10···O1i | 0.86 | 2.08 | 2.929 (2) | 169 |
C20—H20···O2ii | 0.93 | 2.58 | 3.285 (3) | 133 |
Symmetry codes: (i) −x, −y, −z; (ii) −x+1/2, −y+1/2, −z. |
The chemistry of indole compounds has been extensively studied partly due to their use as pharmaceutical and industrial products. Some of the indole derivatives are used as neuroprotectants (Stolc, 1999). Spiro-indoles have been reported to show fungicidal activity (Ali et al., 1989). 5-Chloro-3-(phenylsulfonyl)indole-2-carboxamide is reported to be a highly potent non-nucleoside inhibitor of HIV-1 reverse transcriptase (Williams et al., 1993). The pyrrolizidine alkaloids are well documented for their mutagenic, antineoplastic, carcinogenic, hepatotoxic and many pharmacological activities. In view of the wide spectrum of biological activity of indole and pyrrolizidine derivatives, the X-ray analysis of a pyrrolizidine alkaloid, (I), has been undertaken and the structural details are presented in this communication.
The bond lengths and angles of the indole and benzene ring systems are normal. The pyrrolizidine ring-fusion distance [N1–C5 = 1.481 (2) Å] is in the same range as the other two N—C distances and compares quite well with those observed in related structures (Hay et al., 1982; Sussman & Wodak, 1973; Usha et al., 2005). Bond distances and angles around atom C2 are somewhat distorted, which is due to the spiro-atom character.
The C═O double bond is slightly elongated [C9═O1 = 1.222 (2) Å] due to the hydrogen bonding. This is similar to what was observed for the analogus bond in 1-naphthaleneacetic acid (Rajan, 1984), which forms hydrogen-bonded dimers.
In the title adduct, each molecule is linked to a centrosymmetrically related molecule by N—H···O hydrogen bonds forming R22(8) rings. The nitro group does not play any role in hydrogen bonding, but participates in fairly weak intramolecular contacts (Table 2).
In the pyrrolizidine nucleus, both five-membered rings adopt twist conformations. The smallest displacement asymmetry parameters (Nardelli, 1983) are ΔC2(C5) = 0.018 (1) and ΔC2(C5) = 0.015 (1)°. The overall conformation of the pyrrolizidine nucleus is folded about the bridging bond, viz. N1—C5. The angle between the best planes of the two rings is 54.2 (1)°. This observation is consistent with the structure reported by Usha et al. (2005).