organic compounds
3,3-Dimethyl-1,2,3,4-tetrahydrocyclopenta[b]indole-1,2-dione (bruceolline E)
aDepartment of Biological and Chemical Sciences, University of the West Indies, Cave Hill, Barbados, bDepartment Chemistry, Dartmouth College, Hanover, NH 03755-3564, USA, and cDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA
*Correspondence e-mail: jjasinski@keene.edu
The title compound, C13H11NO2, crystallizes with two molecules in the The crystal packing is stabilized by N—H⋯O hydrogen bonds, which link the molecules into chains along [10], and weak C—H⋯O interactions.
Related literature
For the first isolation of bruceolline E as yellow needles, see: Ouyang et al. (1994). For the first total synthesis of bruceolline E in three steps from the known ethyl indole-1-carboxylate, see: Jordan et al. (2011). For examples of similar tandem acylation/Nazarov with pyrroles, see: Song et al. (2006). For examples of Nazarov cyclizations with indoles, see: Bergman & Venemalm (1992); Cheng & Cheung (1996); Ishikura et al. (2000); Miki et al. (2001); Churruca et al. (2010). For examples of α-diketone oxidations using selenium dioxide, see: Gribble et al. (1988); Xu et al. (2002); Belsey et al. (2006). For related cyclopenta[b]indolone and their analogues, see: Cheng et al. (1991); Garcia-Pichel & Castenholz (1991); Garcia-Pichel et al. (1992); Proteau et al. (1993); Ekebergh et al. (2011); Kobayashi et al. (1994); Jacquemard et al. (2004); Ploutno & Carmeli (2001). For standard bond lengths, see: Allen et al. (1987).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell CrysAlis PRO; data reduction: CrysAlis RED (Oxford Diffraction, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536812000517/qm2048sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812000517/qm2048Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812000517/qm2048Isup3.cml
A solution of 3,3-dimethyl-1,2-dioxo-2,3-dihydro-1H-cyclopenta[b] indole-4-carboxylic acid ethyl ester (0.58 g, 2.03 mmol, 1 eq.), anhydrous THF (30 mL) and TBAF (10.2 mL, 1.0 M in THF, 10.2 mmol, 5.02 eq.) was stirred under argon at reflux for 2 h (Jacquemard et al., 2004). The mixture was allowed to cool before quenching with saturated NH4Cl. After extraction with CH2Cl2 (3 x 40 mL), the organic layers were combined, dried over MgSO4 and concentrated in vacuo to give a yellow solid. Flash
(100% EtOAc) gave the product as a yellow solid (0.42 g, 97%). Crystals suitable for X-ray diffraction were grown from methanol [m.p. 562- 563 K (dec); literature value 562- 564 K (dec)].H1NA and H1NB were located by a Fourier map and refined isotropically. All of the remaining H atoms were placed in their calculated positions and then refined using the riding model with Atom—H lengths of 0.95Å (CH) or 0.98Å (CH3). Isotropic displacement parameters for these atoms were set to 1.19-1.20 (CH) or 1.4-1,50 (CH3) times Ueq of the parent atom.
Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell
CrysAlis PRO (Oxford Diffraction, 2010); data reduction: CrysAlis RED (Oxford Diffraction, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C13H11NO2 | Z = 4 |
Mr = 213.23 | F(000) = 448 |
Triclinic, P1 | Dx = 1.297 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.1091 (7) Å | Cell parameters from 5810 reflections |
b = 11.5337 (8) Å | θ = 3.3–32.3° |
c = 11.8745 (9) Å | µ = 0.09 mm−1 |
α = 63.230 (7)° | T = 170 K |
β = 80.596 (6)° | Block, yellow |
γ = 79.970 (6)° | 0.28 × 0.25 × 0.24 mm |
V = 1091.69 (14) Å3 |
Oxford Diffraction Xcalibur Eos Gemini diffractometer | 5644 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 4698 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.012 |
Detector resolution: 16.1500 pixels mm-1 | θmax = 28.7°, θmin = 3.3° |
ω scans | h = −12→11 |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010) | k = −15→15 |
Tmin = 0.976, Tmax = 0.979 | l = −15→16 |
10062 measured reflections |
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) = 0.157 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0864P)2 + 0.2278P] where P = (Fo2 + 2Fc2)/3 |
5644 reflections | (Δ/σ)max < 0.001 |
299 parameters | Δρmax = 0.36 e Å−3 |
2 restraints | Δρmin = −0.20 e Å−3 |
C13H11NO2 | γ = 79.970 (6)° |
Mr = 213.23 | V = 1091.69 (14) Å3 |
Triclinic, P1 | Z = 4 |
a = 9.1091 (7) Å | Mo Kα radiation |
b = 11.5337 (8) Å | µ = 0.09 mm−1 |
c = 11.8745 (9) Å | T = 170 K |
α = 63.230 (7)° | 0.28 × 0.25 × 0.24 mm |
β = 80.596 (6)° |
Oxford Diffraction Xcalibur Eos Gemini diffractometer | 5644 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010) | 4698 reflections with I > 2σ(I) |
Tmin = 0.976, Tmax = 0.979 | Rint = 0.012 |
10062 measured reflections |
R[F2 > 2σ(F2)] = 0.053 | 2 restraints |
wR(F2) = 0.157 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.36 e Å−3 |
5644 reflections | Δρmin = −0.20 e Å−3 |
299 parameters |
Experimental. 1H NMR (600 MHz, DMSO-d6) δ 12.9 (bs, 1H), 7.85 7.84 (d, J = 8.0 Hz, 1H), 7.62 7.61 (d, J = 8.1 Hz, 1H), 7.42 7.39 (t, J = 7.4 Hz, 1H), 7.34–7.31 (t, J = 7.7 Hz, 1H), 1.44 (s, 6H). 13C NMR (150 MHz, DMSO-d6) δ 206.6, 175.2, 171.0, 140.0, 125.4, 123.4, 121.5, 121.1, 121.0, 113.6, 41.6, 22.9; IR ν(KBr) 3418, 1750, 1665, 1469, 1453, 1210, 1152, 1094, 1013; UV λmax (95% MeOH) 256, 264, 272, 342 nm. Anal. Calcd for C13H11NO2: C, 73.22; H, 5.20; N 6.57. Found: C, 72.48; H, 5.30; N 6.40. |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.75420 (16) | 0.86467 (16) | 0.18664 (11) | 0.0673 (4) | |
O2 | 1.05510 (14) | 0.75658 (14) | 0.25613 (11) | 0.0591 (3) | |
N1 | 0.76832 (12) | 0.67293 (11) | 0.63752 (10) | 0.0329 (2) | |
H1NA | 0.6811 (16) | 0.6811 (16) | 0.6806 (15) | 0.039* | |
C1 | 0.67431 (15) | 0.78837 (13) | 0.41344 (12) | 0.0330 (3) | |
C2 | 0.78552 (17) | 0.80931 (15) | 0.29437 (13) | 0.0413 (3) | |
C3 | 0.94630 (16) | 0.75106 (15) | 0.33304 (13) | 0.0398 (3) | |
C4 | 0.93046 (14) | 0.69760 (13) | 0.46734 (12) | 0.0330 (3) | |
C5 | 1.01358 (15) | 0.62976 (14) | 0.57632 (13) | 0.0358 (3) | |
C6 | 1.16300 (17) | 0.58148 (19) | 0.59556 (18) | 0.0522 (4) | |
H6A | 1.2361 | 0.5907 | 0.5260 | 0.063* | |
C7 | 1.2022 (2) | 0.5200 (2) | 0.7181 (2) | 0.0653 (5) | |
H7A | 1.3038 | 0.4862 | 0.7326 | 0.078* | |
C8 | 1.0970 (2) | 0.5060 (2) | 0.82122 (19) | 0.0618 (5) | |
H8A | 1.1280 | 0.4626 | 0.9044 | 0.074* | |
C9 | 0.94890 (19) | 0.55398 (18) | 0.80488 (15) | 0.0496 (4) | |
H9A | 0.8771 | 0.5453 | 0.8751 | 0.060* | |
C10 | 0.90872 (15) | 0.61552 (14) | 0.68187 (13) | 0.0351 (3) | |
C11 | 0.78265 (14) | 0.71996 (12) | 0.51124 (11) | 0.0289 (3) | |
C12 | 0.6013 (2) | 0.92013 (15) | 0.40795 (16) | 0.0497 (4) | |
H12D | 0.5338 | 0.9061 | 0.4851 | 0.074* | |
H12E | 0.5442 | 0.9664 | 0.3338 | 0.074* | |
H12F | 0.6791 | 0.9724 | 0.4014 | 0.074* | |
C13 | 0.55503 (18) | 0.70394 (18) | 0.42566 (17) | 0.0495 (4) | |
H13D | 0.4878 | 0.6899 | 0.5029 | 0.074* | |
H13E | 0.6036 | 0.6194 | 0.4300 | 0.074* | |
H13F | 0.4972 | 0.7484 | 0.3519 | 0.074* | |
N1A | 0.10484 (12) | 0.81468 (12) | 1.00094 (10) | 0.0343 (3) | |
H1NB | 0.0732 (19) | 0.8074 (16) | 1.0812 (13) | 0.041* | |
O1A | 0.61629 (13) | 0.64860 (15) | 0.94255 (14) | 0.0651 (4) | |
O2A | 0.46978 (13) | 0.73188 (12) | 0.71755 (11) | 0.0529 (3) | |
C1A | 0.38431 (14) | 0.72921 (13) | 1.03441 (13) | 0.0336 (3) | |
C2A | 0.48880 (15) | 0.69922 (14) | 0.93239 (15) | 0.0390 (3) | |
C3A | 0.40683 (16) | 0.74091 (13) | 0.81363 (13) | 0.0370 (3) | |
C4A | 0.25841 (14) | 0.78537 (13) | 0.84578 (12) | 0.0320 (3) | |
C5A | 0.11410 (15) | 0.83713 (13) | 0.79856 (12) | 0.0333 (3) | |
C6A | 0.05507 (19) | 0.87076 (16) | 0.68526 (14) | 0.0452 (3) | |
H6AA | 0.1159 | 0.8600 | 0.6169 | 0.054* | |
C7A | −0.0938 (2) | 0.92010 (18) | 0.67500 (16) | 0.0538 (4) | |
H7AA | −0.1353 | 0.9443 | 0.5980 | 0.065* | |
C8A | −0.18450 (19) | 0.93526 (19) | 0.77470 (18) | 0.0568 (4) | |
H8AA | −0.2867 | 0.9692 | 0.7644 | 0.068* | |
C9A | −0.12946 (17) | 0.90208 (18) | 0.88854 (16) | 0.0490 (4) | |
H9AA | −0.1916 | 0.9120 | 0.9568 | 0.059* | |
C10A | 0.02018 (15) | 0.85378 (13) | 0.89824 (12) | 0.0345 (3) | |
C11A | 0.24447 (14) | 0.77534 (12) | 0.96840 (12) | 0.0292 (3) | |
C12A | 0.37519 (19) | 0.60627 (17) | 1.15941 (16) | 0.0512 (4) | |
H12A | 0.3434 | 0.5371 | 1.1456 | 0.077* | |
H12B | 0.3025 | 0.6255 | 1.2211 | 0.077* | |
H12C | 0.4738 | 0.5772 | 1.1919 | 0.077* | |
C13A | 0.43957 (19) | 0.83897 (17) | 1.04967 (18) | 0.0518 (4) | |
H13A | 0.3713 | 0.8599 | 1.1125 | 0.078* | |
H13B | 0.4424 | 0.9168 | 0.9681 | 0.078* | |
H13C | 0.5403 | 0.8104 | 1.0781 | 0.078* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0641 (8) | 0.0963 (10) | 0.0291 (6) | 0.0029 (7) | −0.0074 (5) | −0.0196 (6) |
O2 | 0.0437 (6) | 0.0938 (9) | 0.0361 (6) | −0.0042 (6) | 0.0117 (5) | −0.0315 (6) |
N1 | 0.0271 (5) | 0.0433 (6) | 0.0241 (5) | −0.0003 (4) | 0.0009 (4) | −0.0134 (4) |
C1 | 0.0307 (6) | 0.0383 (6) | 0.0268 (6) | 0.0014 (5) | −0.0042 (5) | −0.0127 (5) |
C2 | 0.0429 (8) | 0.0511 (8) | 0.0273 (6) | −0.0021 (6) | −0.0012 (5) | −0.0165 (6) |
C3 | 0.0350 (7) | 0.0536 (8) | 0.0310 (7) | −0.0033 (6) | 0.0050 (5) | −0.0217 (6) |
C4 | 0.0268 (6) | 0.0428 (7) | 0.0290 (6) | −0.0010 (5) | 0.0014 (5) | −0.0175 (5) |
C5 | 0.0284 (6) | 0.0448 (7) | 0.0356 (7) | 0.0001 (5) | −0.0040 (5) | −0.0200 (6) |
C6 | 0.0291 (7) | 0.0757 (11) | 0.0557 (10) | 0.0045 (7) | −0.0059 (6) | −0.0351 (9) |
C7 | 0.0378 (8) | 0.0923 (14) | 0.0728 (13) | 0.0151 (9) | −0.0260 (9) | −0.0432 (11) |
C8 | 0.0568 (11) | 0.0806 (13) | 0.0488 (10) | 0.0086 (9) | −0.0269 (8) | −0.0273 (9) |
C9 | 0.0471 (8) | 0.0654 (10) | 0.0334 (7) | 0.0002 (7) | −0.0100 (6) | −0.0190 (7) |
C10 | 0.0308 (6) | 0.0429 (7) | 0.0306 (6) | −0.0012 (5) | −0.0042 (5) | −0.0157 (5) |
C11 | 0.0272 (6) | 0.0335 (6) | 0.0242 (6) | −0.0014 (4) | −0.0002 (4) | −0.0124 (5) |
C12 | 0.0527 (9) | 0.0409 (8) | 0.0455 (8) | 0.0076 (7) | −0.0038 (7) | −0.0149 (7) |
C13 | 0.0394 (8) | 0.0611 (9) | 0.0523 (9) | −0.0075 (7) | −0.0085 (7) | −0.0263 (8) |
N1A | 0.0278 (5) | 0.0469 (6) | 0.0250 (5) | 0.0028 (4) | −0.0006 (4) | −0.0159 (5) |
O1A | 0.0302 (6) | 0.0908 (10) | 0.0778 (9) | 0.0113 (6) | −0.0046 (6) | −0.0463 (8) |
O2A | 0.0440 (6) | 0.0689 (7) | 0.0422 (6) | 0.0004 (5) | 0.0130 (5) | −0.0290 (6) |
C1A | 0.0280 (6) | 0.0371 (6) | 0.0338 (6) | 0.0001 (5) | −0.0046 (5) | −0.0145 (5) |
C2A | 0.0272 (6) | 0.0417 (7) | 0.0461 (8) | −0.0024 (5) | 0.0023 (5) | −0.0199 (6) |
C3A | 0.0342 (7) | 0.0394 (7) | 0.0345 (7) | −0.0039 (5) | 0.0063 (5) | −0.0169 (5) |
C4A | 0.0311 (6) | 0.0372 (6) | 0.0257 (6) | −0.0032 (5) | 0.0011 (5) | −0.0135 (5) |
C5A | 0.0327 (6) | 0.0379 (6) | 0.0271 (6) | −0.0041 (5) | −0.0013 (5) | −0.0126 (5) |
C6A | 0.0510 (9) | 0.0542 (8) | 0.0301 (7) | −0.0077 (7) | −0.0054 (6) | −0.0170 (6) |
C7A | 0.0543 (10) | 0.0644 (10) | 0.0390 (8) | −0.0065 (8) | −0.0201 (7) | −0.0142 (7) |
C8A | 0.0380 (8) | 0.0717 (11) | 0.0517 (10) | 0.0019 (7) | −0.0157 (7) | −0.0179 (8) |
C9A | 0.0313 (7) | 0.0662 (10) | 0.0415 (8) | 0.0043 (7) | −0.0037 (6) | −0.0199 (7) |
C10A | 0.0309 (6) | 0.0406 (7) | 0.0273 (6) | −0.0015 (5) | −0.0031 (5) | −0.0115 (5) |
C11A | 0.0266 (6) | 0.0316 (6) | 0.0261 (6) | −0.0010 (4) | 0.0000 (4) | −0.0112 (5) |
C12A | 0.0402 (8) | 0.0522 (9) | 0.0417 (8) | 0.0038 (6) | −0.0067 (6) | −0.0054 (7) |
C13A | 0.0453 (9) | 0.0570 (9) | 0.0638 (11) | −0.0044 (7) | −0.0134 (8) | −0.0336 (8) |
O1—C2 | 1.2023 (18) | N1A—C11A | 1.3301 (16) |
O2—C3 | 1.2224 (17) | N1A—C10A | 1.4057 (17) |
N1—C11 | 1.3371 (16) | N1A—H1NB | 0.919 (14) |
N1—C10 | 1.4009 (17) | O1A—C2A | 1.2042 (17) |
N1—H1NA | 0.887 (14) | O2A—C3A | 1.2304 (17) |
C1—C11 | 1.4910 (17) | C1A—C11A | 1.4949 (17) |
C1—C12 | 1.5260 (19) | C1A—C12A | 1.525 (2) |
C1—C13 | 1.530 (2) | C1A—C13A | 1.532 (2) |
C1—C2 | 1.5470 (19) | C1A—C2A | 1.5424 (19) |
C2—C3 | 1.551 (2) | C2A—C3A | 1.545 (2) |
C3—C4 | 1.4192 (19) | C3A—C4A | 1.4151 (18) |
C4—C11 | 1.3863 (17) | C4A—C11A | 1.3937 (17) |
C4—C5 | 1.4359 (19) | C4A—C5A | 1.4370 (18) |
C5—C6 | 1.3920 (19) | C5A—C6A | 1.3939 (19) |
C5—C10 | 1.4100 (19) | C5A—C10A | 1.4095 (18) |
C6—C7 | 1.379 (3) | C6A—C7A | 1.378 (2) |
C6—H6A | 0.9500 | C6A—H6AA | 0.9500 |
C7—C8 | 1.392 (3) | C7A—C8A | 1.390 (3) |
C7—H7A | 0.9500 | C7A—H7AA | 0.9500 |
C8—C9 | 1.376 (2) | C8A—C9A | 1.383 (2) |
C8—H8A | 0.9500 | C8A—H8AA | 0.9500 |
C9—C10 | 1.386 (2) | C9A—C10A | 1.3822 (19) |
C9—H9A | 0.9500 | C9A—H9AA | 0.9500 |
C12—H12D | 0.9800 | C12A—H12A | 0.9800 |
C12—H12E | 0.9800 | C12A—H12B | 0.9800 |
C12—H12F | 0.9800 | C12A—H12C | 0.9800 |
C13—H13D | 0.9800 | C13A—H13A | 0.9800 |
C13—H13E | 0.9800 | C13A—H13B | 0.9800 |
C13—H13F | 0.9800 | C13A—H13C | 0.9800 |
C11—N1—C10 | 108.76 (11) | C11A—N1A—C10A | 108.31 (11) |
C11—N1—H1NA | 121.8 (11) | C11A—N1A—H1NB | 122.5 (11) |
C10—N1—H1NA | 129.4 (11) | C10A—N1A—H1NB | 129.0 (11) |
C11—C1—C12 | 113.21 (12) | C11A—C1A—C12A | 114.55 (12) |
C11—C1—C13 | 113.17 (12) | C11A—C1A—C13A | 111.77 (11) |
C12—C1—C13 | 110.52 (13) | C12A—C1A—C13A | 111.60 (14) |
C11—C1—C2 | 98.41 (10) | C11A—C1A—C2A | 97.98 (10) |
C12—C1—C2 | 109.97 (12) | C12A—C1A—C2A | 110.59 (12) |
C13—C1—C2 | 110.99 (12) | C13A—C1A—C2A | 109.51 (12) |
O1—C2—C1 | 125.61 (14) | O1A—C2A—C1A | 125.67 (14) |
O1—C2—C3 | 124.13 (14) | O1A—C2A—C3A | 123.63 (14) |
C1—C2—C3 | 110.25 (11) | C1A—C2A—C3A | 110.69 (11) |
O2—C3—C4 | 132.30 (14) | O2A—C3A—C4A | 132.76 (14) |
O2—C3—C2 | 123.08 (13) | O2A—C3A—C2A | 122.40 (13) |
C4—C3—C2 | 104.62 (11) | C4A—C3A—C2A | 104.84 (11) |
C11—C4—C3 | 110.28 (12) | C11A—C4A—C3A | 109.89 (12) |
C11—C4—C5 | 107.02 (11) | C11A—C4A—C5A | 107.00 (11) |
C3—C4—C5 | 142.68 (12) | C3A—C4A—C5A | 143.11 (13) |
C6—C5—C10 | 119.17 (14) | C6A—C5A—C10A | 119.22 (13) |
C6—C5—C4 | 135.02 (13) | C6A—C5A—C4A | 135.42 (13) |
C10—C5—C4 | 105.80 (11) | C10A—C5A—C4A | 105.36 (11) |
C7—C6—C5 | 118.31 (16) | C7A—C6A—C5A | 118.32 (15) |
C7—C6—H6A | 120.8 | C7A—C6A—H6AA | 120.8 |
C5—C6—H6A | 120.8 | C5A—C6A—H6AA | 120.8 |
C6—C7—C8 | 121.72 (16) | C6A—C7A—C8A | 121.50 (14) |
C6—C7—H7A | 119.1 | C6A—C7A—H7AA | 119.3 |
C8—C7—H7A | 119.1 | C8A—C7A—H7AA | 119.3 |
C9—C8—C7 | 121.20 (16) | C9A—C8A—C7A | 121.55 (15) |
C9—C8—H8A | 119.4 | C9A—C8A—H8AA | 119.2 |
C7—C8—H8A | 119.4 | C7A—C8A—H8AA | 119.2 |
C8—C9—C10 | 117.32 (16) | C10A—C9A—C8A | 116.88 (15) |
C8—C9—H9A | 121.3 | C10A—C9A—H9AA | 121.6 |
C10—C9—H9A | 121.3 | C8A—C9A—H9AA | 121.6 |
C9—C10—N1 | 129.67 (13) | C9A—C10A—N1A | 128.81 (13) |
C9—C10—C5 | 122.27 (13) | C9A—C10A—C5A | 122.53 (13) |
N1—C10—C5 | 108.06 (11) | N1A—C10A—C5A | 108.66 (11) |
N1—C11—C4 | 110.35 (11) | N1A—C11A—C4A | 110.66 (11) |
N1—C11—C1 | 133.24 (11) | N1A—C11A—C1A | 132.96 (12) |
C4—C11—C1 | 116.41 (11) | C4A—C11A—C1A | 116.33 (11) |
C1—C12—H12D | 109.5 | C1A—C12A—H12A | 109.5 |
C1—C12—H12E | 109.5 | C1A—C12A—H12B | 109.5 |
H12D—C12—H12E | 109.5 | H12A—C12A—H12B | 109.5 |
C1—C12—H12F | 109.5 | C1A—C12A—H12C | 109.5 |
H12D—C12—H12F | 109.5 | H12A—C12A—H12C | 109.5 |
H12E—C12—H12F | 109.5 | H12B—C12A—H12C | 109.5 |
C1—C13—H13D | 109.5 | C1A—C13A—H13A | 109.5 |
C1—C13—H13E | 109.5 | C1A—C13A—H13B | 109.5 |
H13D—C13—H13E | 109.5 | H13A—C13A—H13B | 109.5 |
C1—C13—H13F | 109.5 | C1A—C13A—H13C | 109.5 |
H13D—C13—H13F | 109.5 | H13A—C13A—H13C | 109.5 |
H13E—C13—H13F | 109.5 | H13B—C13A—H13C | 109.5 |
C11—C1—C2—O1 | −178.28 (17) | C11A—C1A—C2A—O1A | −174.04 (15) |
C12—C1—C2—O1 | −59.7 (2) | C12A—C1A—C2A—O1A | −54.0 (2) |
C13—C1—C2—O1 | 62.9 (2) | C13A—C1A—C2A—O1A | 69.41 (19) |
C11—C1—C2—C3 | 0.43 (15) | C11A—C1A—C2A—C3A | 4.93 (13) |
C12—C1—C2—C3 | 118.96 (14) | C12A—C1A—C2A—C3A | 124.99 (13) |
C13—C1—C2—C3 | −118.44 (13) | C13A—C1A—C2A—C3A | −111.62 (13) |
O1—C2—C3—O2 | −0.2 (3) | O1A—C2A—C3A—O2A | −4.3 (2) |
C1—C2—C3—O2 | −178.95 (15) | C1A—C2A—C3A—O2A | 176.71 (13) |
O1—C2—C3—C4 | 179.30 (17) | O1A—C2A—C3A—C4A | 175.40 (15) |
C1—C2—C3—C4 | 0.57 (16) | C1A—C2A—C3A—C4A | −3.60 (15) |
O2—C3—C4—C11 | 178.02 (17) | O2A—C3A—C4A—C11A | −179.98 (16) |
C2—C3—C4—C11 | −1.44 (16) | C2A—C3A—C4A—C11A | 0.37 (15) |
O2—C3—C4—C5 | −0.2 (3) | O2A—C3A—C4A—C5A | 0.6 (3) |
C2—C3—C4—C5 | −179.69 (18) | C2A—C3A—C4A—C5A | −179.08 (17) |
C11—C4—C5—C6 | −179.60 (17) | C11A—C4A—C5A—C6A | 179.17 (16) |
C3—C4—C5—C6 | −1.3 (3) | C3A—C4A—C5A—C6A | −1.4 (3) |
C11—C4—C5—C10 | −0.31 (15) | C11A—C4A—C5A—C10A | −0.72 (15) |
C3—C4—C5—C10 | 177.97 (19) | C3A—C4A—C5A—C10A | 178.74 (17) |
C10—C5—C6—C7 | 0.7 (3) | C10A—C5A—C6A—C7A | 0.4 (2) |
C4—C5—C6—C7 | 179.91 (18) | C4A—C5A—C6A—C7A | −179.47 (16) |
C5—C6—C7—C8 | −0.3 (3) | C5A—C6A—C7A—C8A | −0.6 (3) |
C6—C7—C8—C9 | −0.4 (3) | C6A—C7A—C8A—C9A | 0.3 (3) |
C7—C8—C9—C10 | 0.6 (3) | C7A—C8A—C9A—C10A | 0.3 (3) |
C8—C9—C10—N1 | −179.92 (16) | C8A—C9A—C10A—N1A | 178.99 (15) |
C8—C9—C10—C5 | −0.2 (3) | C8A—C9A—C10A—C5A | −0.6 (3) |
C11—N1—C10—C9 | −179.70 (16) | C11A—N1A—C10A—C9A | −179.67 (15) |
C11—N1—C10—C5 | 0.51 (16) | C11A—N1A—C10A—C5A | −0.06 (16) |
C6—C5—C10—C9 | −0.5 (2) | C6A—C5A—C10A—C9A | 0.2 (2) |
C4—C5—C10—C9 | −179.92 (15) | C4A—C5A—C10A—C9A | −179.88 (14) |
C6—C5—C10—N1 | 179.31 (14) | C6A—C5A—C10A—N1A | −179.42 (13) |
C4—C5—C10—N1 | −0.11 (15) | C4A—C5A—C10A—N1A | 0.48 (15) |
C10—N1—C11—C4 | −0.73 (15) | C10A—N1A—C11A—C4A | −0.41 (15) |
C10—N1—C11—C1 | 179.04 (14) | C10A—N1A—C11A—C1A | 176.95 (13) |
C3—C4—C11—N1 | −178.24 (12) | C3A—C4A—C11A—N1A | −178.94 (11) |
C5—C4—C11—N1 | 0.65 (16) | C5A—C4A—C11A—N1A | 0.72 (15) |
C3—C4—C11—C1 | 1.95 (17) | C3A—C4A—C11A—C1A | 3.22 (16) |
C5—C4—C11—C1 | −179.16 (11) | C5A—C4A—C11A—C1A | −177.13 (11) |
C12—C1—C11—N1 | 62.8 (2) | C12A—C1A—C11A—N1A | 60.7 (2) |
C13—C1—C11—N1 | −63.97 (19) | C13A—C1A—C11A—N1A | −67.49 (19) |
C2—C1—C11—N1 | 178.83 (15) | C2A—C1A—C11A—N1A | 177.73 (14) |
C12—C1—C11—C4 | −117.46 (14) | C12A—C1A—C11A—C4A | −122.05 (14) |
C13—C1—C11—C4 | 115.79 (14) | C13A—C1A—C11A—C4A | 109.76 (14) |
C2—C1—C11—C4 | −1.41 (15) | C2A—C1A—C11A—C4A | −5.02 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1NA···O2A | 0.89 (1) | 1.95 (1) | 2.8025 (16) | 161 (2) |
N1A—H1NB···O2i | 0.92 (1) | 1.87 (1) | 2.7686 (16) | 164 (2) |
C9A—H9AA···O1i | 0.95 | 2.51 | 3.376 (2) | 152 |
C12A—H12B···O2i | 0.98 | 2.57 | 3.430 (2) | 146 |
Symmetry code: (i) x−1, y, z+1. |
Experimental details
Crystal data | |
Chemical formula | C13H11NO2 |
Mr | 213.23 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 170 |
a, b, c (Å) | 9.1091 (7), 11.5337 (8), 11.8745 (9) |
α, β, γ (°) | 63.230 (7), 80.596 (6), 79.970 (6) |
V (Å3) | 1091.69 (14) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.28 × 0.25 × 0.24 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur Eos Gemini diffractometer |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2010) |
Tmin, Tmax | 0.976, 0.979 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10062, 5644, 4698 |
Rint | 0.012 |
(sin θ/λ)max (Å−1) | 0.676 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.053, 0.157, 1.05 |
No. of reflections | 5644 |
No. of parameters | 299 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.36, −0.20 |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2010), CrysAlis RED (Oxford Diffraction, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1NA···O2A | 0.887 (14) | 1.950 (14) | 2.8025 (16) | 160.7 (16) |
N1A—H1NB···O2i | 0.919 (14) | 1.874 (14) | 2.7686 (16) | 163.9 (16) |
C9A—H9AA···O1i | 0.95 | 2.51 | 3.376 (2) | 151.6 |
C12A—H12B···O2i | 0.98 | 2.57 | 3.430 (2) | 146.3 |
Symmetry code: (i) x−1, y, z+1. |
Acknowledgements
JCB wishes to thank the School of Graduate Studies and Research, UWI, and the Government of Barbados for the funding of this research. JPJ acknowledges the NSF–MRI program (grant No. CHE1039027) for funds to purchase the X-ray diffractometer.
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The fused indole alkaloid bruceolline E was first isolated as yellow needles from the root wood Brucea mollis Wall. Var. tonkinensis Lecomte and reported by Ohmoto (Ouyang et al., 1994). Our synthesis of this cyclopenta[b]indolone natural product included a tandem acylation/Nazarov cyclization sequence (Song et al., 2006) and insertion of the α-diketone functionality using selenium dioxide (Gribble et al., 1988) in 60% yield. Similar Nazarov cyclizations with indoles (Bergman & Venemalm, 1992; Cheng & Cheung, 1996; Ishikura et al., 2000; Miki et al., 2001; Churruca et al., 2010) have been reported. Related α-diketone oxidations using selenium dioxide (Xu et al., 2002; Belsey et al., 2006) and cyclopenta[b]indolone natural product alkaloid analogues such as scytonemin (Garcia-Pichel & Castenholz 1991; Garcia-Pichel et al. 1992; Proteau et al. 1993; Ekebergh et al. 2011), nostodione (Kobayashi et al., 1994) and prenostodione (Ploutno & Carmeli, 2001) have also been reported. Our efforts have yielded the first total synthesis of bruceolline E (Jordan et al., 2011), in three steps from the known ethyl indole-1-carboxylate.
We now report herein the first crystal structure of the title compound, C13H11NO2, bruceolline E, which confirms the cyclopenta[b] indole moiety and the α-diketone functionalities earlier assigned by NMR methods.
In the crystal structure of the title compound, C13H11NO2, two molecules crystallize in the asymmetric unit (Fig. 1). Bond lengths are in normal ranges (Allen et al., 1987). Crystal packing is stabilized by N—H···O hydrogen bonds (Table 1) and weak C—H···O intermolecular interactions linking these 1-D chains along [011] (Fig. 2).