organic compounds
tert-Butyl 3-[2,2-bis(ethoxycarbonyl)vinyl]-2-methyl-1H-indole-1-carboxylate
aCentre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India, and bDepartment of Organic Chemistry, University of Madras, Guindy Campus, Chennai 600 025, India
*Correspondence e-mail: mnpsy2004@yahoo.com
In the title compound, C22H27NO6, the indole ring system is planar and the ethoxycarbonyl chains adopt extended conformations. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds occur, resulting in R22(16) dimers, which are interlinked into a chain propagating along the a axis by π–π stacking interactions [centroid–centroid distance 3.5916 (9) Å].
Related literature
For general background, see: Hood et al. (1992); Cram et al. (2001). For see: Beddoes et al. (1986). For hydrogen-bond motifs, see: Bernstein et al. (1995).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2004); cell SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536809009635/ci2766sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809009635/ci2766Isup2.hkl
To a solution of tert-butyl 3-formyl-2-methyl-1H-indole-1-carboxylate (4 g, 15.44 mmol) in dry benzene (120 ml), diethylmalonate (2.8 ml, 18.53 mmol), piperidine (6 drops) and acetic acid (3 drops) were added and refluxed in Dean-Stark apparatus for 48 h. Removal of solvent followed by recrystallization from methanol afforded the product as brown crystals.
The ethyl C atoms of the ethoxycarbonyl group are disordered over two positions (C21A/C22A and C21B/C22B) with refined occupancies of 0.58 (1) and 0.42 (1). The corresponding O—C and C—C bond distances involving the disordered atoms were restrained to 1.45 (1) Å and 1.53 (1) Å, respectively, and also their Uij parameters were restrained to an approximate isotropic behaviour. H atoms were positioned geometrically (C—H = 0.93–0.97 Å) and allowed to ride on their parent atoms, with Uiso(H) = 1.2–1.5(methyl)Ueq(C).
Data collection: APEX2 (Bruker, 2004); cell
SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).C22H27NO6 | F(000) = 856 |
Mr = 401.45 | Dx = 1.241 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4766 reflections |
a = 9.1933 (3) Å | θ = 2.1–27.2° |
b = 21.8495 (6) Å | µ = 0.09 mm−1 |
c = 10.7676 (3) Å | T = 293 K |
β = 96.510 (2)° | Block, brown |
V = 2148.93 (11) Å3 | 0.25 × 0.20 × 0.20 mm |
Z = 4 |
Bruker Kappa APEXII area-detector diffractometer | 4766 independent reflections |
Radiation source: fine-focus sealed tube | 3534 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
ω and ϕ scans | θmax = 27.2°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | h = −11→11 |
Tmin = 0.978, Tmax = 0.982 | k = −27→28 |
24241 measured reflections | l = −13→13 |
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)] = 0.049 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.134 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0561P)2 + 0.6467P] where P = (Fo2 + 2Fc2)/3 |
4766 reflections | (Δ/σ)max = 0.001 |
286 parameters | Δρmax = 0.25 e Å−3 |
28 restraints | Δρmin = −0.28 e Å−3 |
C22H27NO6 | V = 2148.93 (11) Å3 |
Mr = 401.45 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.1933 (3) Å | µ = 0.09 mm−1 |
b = 21.8495 (6) Å | T = 293 K |
c = 10.7676 (3) Å | 0.25 × 0.20 × 0.20 mm |
β = 96.510 (2)° |
Bruker Kappa APEXII area-detector diffractometer | 4766 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | 3534 reflections with I > 2σ(I) |
Tmin = 0.978, Tmax = 0.982 | Rint = 0.030 |
24241 measured reflections |
R[F2 > 2σ(F2)] = 0.049 | 28 restraints |
wR(F2) = 0.134 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.25 e Å−3 |
4766 reflections | Δρmin = −0.28 e Å−3 |
286 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.11345 (14) | 0.63504 (5) | 0.68637 (11) | 0.0507 (3) | |
O2 | 0.00198 (17) | 0.68868 (6) | 0.52523 (12) | 0.0639 (4) | |
O3 | 0.39872 (13) | 0.51263 (5) | 0.24128 (12) | 0.0508 (3) | |
O4 | 0.34111 (19) | 0.43222 (8) | 0.11765 (15) | 0.0797 (5) | |
O5 | 0.3720 (2) | 0.33528 (7) | 0.4564 (2) | 0.0942 (6) | |
O6 | 0.49107 (19) | 0.34337 (7) | 0.2910 (2) | 0.0947 (6) | |
N1 | 0.09171 (14) | 0.59345 (5) | 0.49600 (12) | 0.0370 (3) | |
C2 | 0.03282 (17) | 0.58731 (7) | 0.37025 (14) | 0.0378 (3) | |
C3 | −0.06844 (19) | 0.62313 (8) | 0.29745 (16) | 0.0482 (4) | |
H3 | −0.1061 | 0.6587 | 0.3287 | 0.058* | |
C4 | −0.1107 (2) | 0.60389 (9) | 0.17750 (17) | 0.0572 (5) | |
H4 | −0.1775 | 0.6273 | 0.1263 | 0.069* | |
C5 | −0.0566 (2) | 0.55057 (10) | 0.13070 (16) | 0.0571 (5) | |
H5 | −0.0877 | 0.5387 | 0.0490 | 0.069* | |
C6 | 0.0423 (2) | 0.51497 (9) | 0.20315 (16) | 0.0491 (4) | |
H6 | 0.0776 | 0.4790 | 0.1715 | 0.059* | |
C7 | 0.08915 (17) | 0.53353 (7) | 0.32463 (14) | 0.0386 (3) | |
C8 | 0.18327 (17) | 0.50633 (7) | 0.42574 (15) | 0.0381 (3) | |
C9 | 0.18175 (16) | 0.54260 (7) | 0.52819 (14) | 0.0368 (3) | |
C10 | 0.06355 (18) | 0.64434 (7) | 0.56895 (15) | 0.0425 (4) | |
C11 | 0.1044 (2) | 0.68359 (8) | 0.78201 (17) | 0.0514 (4) | |
C12 | 0.1872 (3) | 0.65426 (12) | 0.89548 (19) | 0.0792 (7) | |
H12A | 0.1399 | 0.6167 | 0.9140 | 0.119* | |
H12B | 0.1885 | 0.6815 | 0.9655 | 0.119* | |
H12C | 0.2857 | 0.6459 | 0.8792 | 0.119* | |
C13 | 0.1810 (2) | 0.74056 (9) | 0.7464 (2) | 0.0657 (5) | |
H13A | 0.2768 | 0.7302 | 0.7256 | 0.099* | |
H13B | 0.1897 | 0.7687 | 0.8153 | 0.099* | |
H13C | 0.1256 | 0.7592 | 0.6754 | 0.099* | |
C14 | −0.0535 (2) | 0.69411 (10) | 0.7993 (2) | 0.0672 (6) | |
H14A | −0.1032 | 0.7120 | 0.7248 | 0.101* | |
H14B | −0.0595 | 0.7213 | 0.8686 | 0.101* | |
H14C | −0.0986 | 0.6558 | 0.8157 | 0.101* | |
C15 | 0.26345 (17) | 0.44895 (7) | 0.42693 (16) | 0.0431 (4) | |
H15 | 0.2655 | 0.4263 | 0.5002 | 0.052* | |
C16 | 0.33461 (18) | 0.42406 (7) | 0.33802 (17) | 0.0465 (4) | |
C17 | 0.35749 (19) | 0.45525 (8) | 0.21940 (18) | 0.0513 (4) | |
C18 | 0.4202 (3) | 0.55038 (11) | 0.1348 (2) | 0.0752 (6) | |
H18A | 0.3363 | 0.5474 | 0.0718 | 0.090* | |
H18B | 0.5067 | 0.5373 | 0.0981 | 0.090* | |
C19 | 0.4382 (4) | 0.61385 (13) | 0.1811 (3) | 0.1133 (11) | |
H19A | 0.3498 | 0.6270 | 0.2128 | 0.170* | |
H19B | 0.4585 | 0.6402 | 0.1139 | 0.170* | |
H19C | 0.5179 | 0.6156 | 0.2468 | 0.170* | |
C20 | 0.4073 (2) | 0.36390 (8) | 0.3563 (2) | 0.0626 (5) | |
C21A | 0.4535 (8) | 0.2800 (2) | 0.5168 (11) | 0.093 (2) | 0.580 (10) |
H21A | 0.5473 | 0.2741 | 0.4853 | 0.111* | 0.580 (10) |
H21B | 0.4684 | 0.2836 | 0.6071 | 0.111* | 0.580 (10) |
C22A | 0.3500 (8) | 0.2300 (3) | 0.4765 (13) | 0.089 (3) | 0.420 (10) |
H22A | 0.3897 | 0.1917 | 0.5081 | 0.134* | 0.420 (10) |
H22B | 0.3350 | 0.2286 | 0.3869 | 0.134* | 0.420 (10) |
H22C | 0.2582 | 0.2374 | 0.5084 | 0.134* | 0.420 (10) |
C21B | 0.4319 (10) | 0.2723 (3) | 0.4519 (9) | 0.0645 (19) | 0.420 (10) |
H21C | 0.3936 | 0.2511 | 0.3760 | 0.077* | 0.420 (10) |
H21D | 0.5380 | 0.2724 | 0.4591 | 0.077* | 0.420 (10) |
C22B | 0.3768 (8) | 0.2453 (3) | 0.5638 (9) | 0.096 (2) | 0.580 (10) |
H22D | 0.4068 | 0.2033 | 0.5719 | 0.144* | 0.580 (10) |
H22E | 0.2718 | 0.2475 | 0.5552 | 0.144* | 0.580 (10) |
H22F | 0.4160 | 0.2675 | 0.6369 | 0.144* | 0.580 (10) |
C23 | 0.26713 (19) | 0.53322 (8) | 0.65178 (16) | 0.0478 (4) | |
H23A | 0.3283 | 0.4978 | 0.6487 | 0.072* | |
H23B | 0.2014 | 0.5273 | 0.7139 | 0.072* | |
H23C | 0.3271 | 0.5685 | 0.6729 | 0.072* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0686 (8) | 0.0437 (6) | 0.0384 (6) | 0.0115 (6) | −0.0001 (6) | −0.0066 (5) |
O2 | 0.0922 (10) | 0.0455 (7) | 0.0517 (8) | 0.0258 (7) | −0.0018 (7) | −0.0023 (6) |
O3 | 0.0479 (7) | 0.0487 (7) | 0.0557 (8) | 0.0009 (5) | 0.0059 (6) | 0.0031 (5) |
O4 | 0.0929 (12) | 0.0852 (11) | 0.0638 (9) | −0.0061 (9) | 0.0205 (8) | −0.0259 (8) |
O5 | 0.0943 (12) | 0.0479 (8) | 0.1461 (17) | 0.0286 (8) | 0.0386 (12) | 0.0268 (10) |
O6 | 0.0797 (11) | 0.0628 (10) | 0.1485 (17) | 0.0245 (8) | 0.0437 (11) | −0.0134 (10) |
N1 | 0.0403 (7) | 0.0349 (6) | 0.0353 (7) | 0.0041 (5) | 0.0019 (5) | −0.0001 (5) |
C2 | 0.0400 (8) | 0.0386 (8) | 0.0349 (8) | 0.0015 (6) | 0.0047 (6) | 0.0018 (6) |
C3 | 0.0525 (10) | 0.0458 (9) | 0.0454 (10) | 0.0110 (7) | 0.0022 (8) | 0.0056 (7) |
C4 | 0.0592 (11) | 0.0679 (12) | 0.0421 (10) | 0.0134 (9) | −0.0045 (8) | 0.0110 (8) |
C5 | 0.0597 (11) | 0.0756 (13) | 0.0348 (9) | 0.0058 (10) | −0.0003 (8) | −0.0023 (8) |
C6 | 0.0504 (10) | 0.0566 (10) | 0.0406 (9) | 0.0053 (8) | 0.0058 (7) | −0.0074 (7) |
C7 | 0.0378 (8) | 0.0409 (8) | 0.0375 (8) | 0.0012 (6) | 0.0058 (6) | 0.0008 (6) |
C8 | 0.0361 (8) | 0.0367 (8) | 0.0416 (9) | 0.0019 (6) | 0.0050 (6) | 0.0006 (6) |
C9 | 0.0337 (7) | 0.0344 (7) | 0.0419 (8) | 0.0017 (6) | 0.0027 (6) | 0.0028 (6) |
C10 | 0.0488 (9) | 0.0369 (8) | 0.0417 (9) | 0.0052 (7) | 0.0043 (7) | −0.0016 (7) |
C11 | 0.0596 (11) | 0.0500 (10) | 0.0446 (10) | 0.0031 (8) | 0.0055 (8) | −0.0149 (7) |
C12 | 0.1044 (18) | 0.0845 (16) | 0.0454 (11) | 0.0108 (14) | −0.0056 (11) | −0.0163 (11) |
C13 | 0.0655 (13) | 0.0569 (11) | 0.0758 (14) | −0.0066 (9) | 0.0130 (11) | −0.0185 (10) |
C14 | 0.0648 (13) | 0.0679 (13) | 0.0716 (14) | −0.0075 (10) | 0.0198 (11) | −0.0251 (10) |
C15 | 0.0403 (8) | 0.0369 (8) | 0.0517 (10) | 0.0015 (6) | 0.0037 (7) | 0.0014 (7) |
C16 | 0.0400 (9) | 0.0372 (8) | 0.0625 (11) | 0.0010 (7) | 0.0070 (8) | −0.0074 (7) |
C17 | 0.0416 (9) | 0.0527 (10) | 0.0606 (11) | 0.0030 (8) | 0.0098 (8) | −0.0116 (9) |
C18 | 0.0777 (15) | 0.0826 (16) | 0.0658 (14) | −0.0049 (12) | 0.0107 (11) | 0.0210 (12) |
C19 | 0.147 (3) | 0.0703 (17) | 0.117 (2) | −0.0217 (17) | −0.009 (2) | 0.0326 (16) |
C20 | 0.0486 (10) | 0.0378 (9) | 0.1030 (17) | 0.0015 (8) | 0.0151 (11) | −0.0059 (10) |
C21A | 0.107 (4) | 0.057 (3) | 0.112 (5) | 0.024 (3) | 0.001 (4) | 0.002 (4) |
C22A | 0.094 (4) | 0.072 (4) | 0.101 (6) | 0.004 (3) | 0.008 (4) | 0.009 (4) |
C21B | 0.090 (4) | 0.038 (3) | 0.067 (4) | 0.022 (3) | 0.014 (3) | 0.011 (3) |
C22B | 0.117 (4) | 0.073 (3) | 0.102 (5) | 0.028 (3) | 0.031 (4) | 0.037 (3) |
C23 | 0.0466 (9) | 0.0463 (9) | 0.0477 (10) | 0.0074 (7) | −0.0065 (7) | 0.0002 (7) |
O1—C10 | 1.311 (2) | C12—H12C | 0.96 |
O1—C11 | 1.4874 (19) | C13—H13A | 0.96 |
O2—C10 | 1.1917 (19) | C13—H13B | 0.96 |
O3—C17 | 1.323 (2) | C13—H13C | 0.96 |
O3—C18 | 1.444 (2) | C14—H14A | 0.96 |
O4—C17 | 1.200 (2) | C14—H14B | 0.96 |
O5—C20 | 1.318 (3) | C14—H14C | 0.96 |
O5—C21B | 1.484 (6) | C15—C16 | 1.335 (2) |
O5—C21A | 1.528 (6) | C15—H15 | 0.93 |
O6—C20 | 1.188 (2) | C16—C20 | 1.478 (2) |
N1—C10 | 1.402 (2) | C16—C17 | 1.484 (3) |
N1—C9 | 1.4053 (19) | C18—C19 | 1.477 (4) |
N1—C2 | 1.4065 (19) | C18—H18A | 0.97 |
C2—C3 | 1.389 (2) | C18—H18B | 0.97 |
C2—C7 | 1.396 (2) | C19—H19A | 0.96 |
C3—C4 | 1.372 (3) | C19—H19B | 0.96 |
C3—H3 | 0.93 | C19—H19C | 0.96 |
C4—C5 | 1.384 (3) | C21A—C22A | 1.481 (7) |
C4—H4 | 0.93 | C21A—H21A | 0.97 |
C5—C6 | 1.371 (3) | C21A—H21B | 0.97 |
C5—H5 | 0.93 | C22A—H22A | 0.96 |
C6—C7 | 1.390 (2) | C22A—H22B | 0.96 |
C6—H6 | 0.93 | C22A—H22C | 0.96 |
C7—C8 | 1.440 (2) | C21B—C22B | 1.482 (6) |
C8—C9 | 1.360 (2) | C21B—H21C | 0.97 |
C8—C15 | 1.454 (2) | C21B—H21D | 0.97 |
C9—C23 | 1.481 (2) | C22B—H22D | 0.96 |
C11—C13 | 1.501 (3) | C22B—H22E | 0.96 |
C11—C14 | 1.502 (3) | C22B—H22F | 0.96 |
C11—C12 | 1.507 (3) | C23—H23A | 0.96 |
C12—H12A | 0.96 | C23—H23B | 0.96 |
C12—H12B | 0.96 | C23—H23C | 0.96 |
C10—O1—C11 | 121.09 (13) | H14A—C14—H14C | 109.5 |
C17—O3—C18 | 117.53 (16) | H14B—C14—H14C | 109.5 |
C20—O5—C21B | 106.6 (3) | C16—C15—C8 | 129.37 (16) |
C20—O5—C21A | 124.6 (4) | C16—C15—H15 | 115.3 |
C10—N1—C9 | 129.03 (13) | C8—C15—H15 | 115.3 |
C10—N1—C2 | 122.65 (12) | C15—C16—C20 | 121.19 (18) |
C9—N1—C2 | 108.28 (12) | C15—C16—C17 | 123.98 (15) |
C3—C2—C7 | 121.85 (15) | C20—C16—C17 | 114.67 (16) |
C3—C2—N1 | 130.54 (15) | O4—C17—O3 | 124.32 (19) |
C7—C2—N1 | 107.54 (13) | O4—C17—C16 | 125.33 (18) |
C4—C3—C2 | 117.33 (16) | O3—C17—C16 | 110.35 (15) |
C4—C3—H3 | 121.3 | O3—C18—C19 | 106.8 (2) |
C2—C3—H3 | 121.3 | O3—C18—H18A | 110.4 |
C3—C4—C5 | 121.69 (17) | C19—C18—H18A | 110.4 |
C3—C4—H4 | 119.2 | O3—C18—H18B | 110.4 |
C5—C4—H4 | 119.2 | C19—C18—H18B | 110.4 |
C6—C5—C4 | 120.87 (17) | H18A—C18—H18B | 108.6 |
C6—C5—H5 | 119.6 | C18—C19—H19A | 109.5 |
C4—C5—H5 | 119.6 | C18—C19—H19B | 109.5 |
C5—C6—C7 | 118.98 (17) | H19A—C19—H19B | 109.5 |
C5—C6—H6 | 120.5 | C18—C19—H19C | 109.5 |
C7—C6—H6 | 120.5 | H19A—C19—H19C | 109.5 |
C6—C7—C2 | 119.28 (15) | H19B—C19—H19C | 109.5 |
C6—C7—C8 | 133.34 (15) | O6—C20—O5 | 122.79 (19) |
C2—C7—C8 | 107.25 (13) | O6—C20—C16 | 124.8 (2) |
C9—C8—C7 | 108.20 (13) | O5—C20—C16 | 112.41 (17) |
C9—C8—C15 | 123.19 (14) | C22A—C21A—O5 | 101.0 (5) |
C7—C8—C15 | 128.55 (15) | C22A—C21A—H21A | 111.6 |
C8—C9—N1 | 108.70 (13) | O5—C21A—H21A | 111.6 |
C8—C9—C23 | 126.54 (14) | C22A—C21A—H21B | 111.6 |
N1—C9—C23 | 124.65 (14) | O5—C21A—H21B | 111.6 |
O2—C10—O1 | 127.26 (15) | H21A—C21A—H21B | 109.4 |
O2—C10—N1 | 122.20 (15) | C21A—C22A—H22A | 109.5 |
O1—C10—N1 | 110.53 (13) | C21A—C22A—H22B | 109.5 |
O1—C11—C13 | 110.46 (15) | H22A—C22A—H22B | 109.5 |
O1—C11—C14 | 109.02 (15) | C21A—C22A—H22C | 109.5 |
C13—C11—C14 | 113.14 (17) | H22A—C22A—H22C | 109.5 |
O1—C11—C12 | 101.26 (14) | H22B—C22A—H22C | 109.5 |
C13—C11—C12 | 110.58 (18) | C22B—C21B—O5 | 100.4 (4) |
C14—C11—C12 | 111.74 (19) | C22B—C21B—H21C | 111.7 |
C11—C12—H12A | 109.5 | O5—C21B—H21C | 111.7 |
C11—C12—H12B | 109.5 | C22B—C21B—H21D | 111.7 |
H12A—C12—H12B | 109.5 | O5—C21B—H21D | 111.7 |
C11—C12—H12C | 109.5 | H21C—C21B—H21D | 109.5 |
H12A—C12—H12C | 109.5 | C21B—C22B—H22D | 109.5 |
H12B—C12—H12C | 109.5 | C21B—C22B—H22E | 109.5 |
C11—C13—H13A | 109.5 | H22D—C22B—H22E | 109.5 |
C11—C13—H13B | 109.5 | C21B—C22B—H22F | 109.5 |
H13A—C13—H13B | 109.5 | H22D—C22B—H22F | 109.5 |
C11—C13—H13C | 109.5 | H22E—C22B—H22F | 109.5 |
H13A—C13—H13C | 109.5 | C9—C23—H23A | 109.5 |
H13B—C13—H13C | 109.5 | C9—C23—H23B | 109.5 |
C11—C14—H14A | 109.5 | H23A—C23—H23B | 109.5 |
C11—C14—H14B | 109.5 | C9—C23—H23C | 109.5 |
H14A—C14—H14B | 109.5 | H23A—C23—H23C | 109.5 |
C11—C14—H14C | 109.5 | H23B—C23—H23C | 109.5 |
C10—N1—C2—C3 | −6.4 (3) | C2—N1—C10—O2 | −8.8 (3) |
C9—N1—C2—C3 | 175.54 (17) | C9—N1—C10—O1 | −11.4 (2) |
C10—N1—C2—C7 | 176.75 (14) | C2—N1—C10—O1 | 171.02 (14) |
C9—N1—C2—C7 | −1.29 (16) | C10—O1—C11—C13 | −57.4 (2) |
C7—C2—C3—C4 | −0.5 (3) | C10—O1—C11—C14 | 67.5 (2) |
N1—C2—C3—C4 | −176.98 (17) | C10—O1—C11—C12 | −174.57 (17) |
C2—C3—C4—C5 | 0.8 (3) | C9—C8—C15—C16 | −143.93 (18) |
C3—C4—C5—C6 | −0.2 (3) | C7—C8—C15—C16 | 39.3 (3) |
C4—C5—C6—C7 | −0.7 (3) | C8—C15—C16—C20 | −178.54 (16) |
C5—C6—C7—C2 | 0.9 (3) | C8—C15—C16—C17 | 6.3 (3) |
C5—C6—C7—C8 | 176.11 (18) | C18—O3—C17—O4 | 2.3 (3) |
C3—C2—C7—C6 | −0.3 (2) | C18—O3—C17—C16 | −177.62 (16) |
N1—C2—C7—C6 | 176.85 (14) | C15—C16—C17—O4 | −135.4 (2) |
C3—C2—C7—C8 | −176.65 (15) | C20—C16—C17—O4 | 49.2 (3) |
N1—C2—C7—C8 | 0.51 (17) | C15—C16—C17—O3 | 44.5 (2) |
C6—C7—C8—C9 | −175.13 (18) | C20—C16—C17—O3 | −130.88 (16) |
C2—C7—C8—C9 | 0.47 (18) | C17—O3—C18—C19 | 169.7 (2) |
C6—C7—C8—C15 | 2.0 (3) | C21B—O5—C20—O6 | −10.6 (5) |
C2—C7—C8—C15 | 177.64 (15) | C21A—O5—C20—O6 | 13.0 (5) |
C7—C8—C9—N1 | −1.27 (17) | C21B—O5—C20—C16 | 170.9 (5) |
C15—C8—C9—N1 | −178.63 (14) | C21A—O5—C20—C16 | −165.5 (4) |
C7—C8—C9—C23 | −177.64 (15) | C15—C16—C20—O6 | −167.6 (2) |
C15—C8—C9—C23 | 5.0 (3) | C17—C16—C20—O6 | 8.0 (3) |
C10—N1—C9—C8 | −176.27 (15) | C15—C16—C20—O5 | 10.9 (3) |
C2—N1—C9—C8 | 1.60 (17) | C17—C16—C20—O5 | −173.58 (18) |
C10—N1—C9—C23 | 0.2 (2) | C20—O5—C21A—C22A | −105.2 (6) |
C2—N1—C9—C23 | 178.06 (15) | C21B—O5—C21A—C22A | −49.7 (9) |
C11—O1—C10—O2 | −3.5 (3) | C20—O5—C21B—C22B | −176.8 (5) |
C11—O1—C10—N1 | 176.67 (14) | C21A—O5—C21B—C22B | 48.2 (9) |
C9—N1—C10—O2 | 168.77 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
C23—H23C···O6i | 0.96 | 2.55 | 3.503 (3) | 171 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C22H27NO6 |
Mr | 401.45 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 293 |
a, b, c (Å) | 9.1933 (3), 21.8495 (6), 10.7676 (3) |
β (°) | 96.510 (2) |
V (Å3) | 2148.93 (11) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.25 × 0.20 × 0.20 |
Data collection | |
Diffractometer | Bruker Kappa APEXII area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2001) |
Tmin, Tmax | 0.978, 0.982 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 24241, 4766, 3534 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.643 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.049, 0.134, 1.04 |
No. of reflections | 4766 |
No. of parameters | 286 |
No. of restraints | 28 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.28 |
Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C23—H23C···O6i | 0.96 | 2.55 | 3.503 (3) | 171 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Acknowledgements
MT thanks Dr Babu Varghese, SAIF, IIT–Madras, India, for his help with the data collection.
References
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Indole-carboxylate derivatives are known to be sensitive to N-methyl-D-aspartate (NMDA) antagonists and capable of reducing the damage associated with an ischemic insult in Mongolian gerbil hippocampal neurons (Hood et al., 1992). Also the naturally occurring indole compounds can induce cell cycle to arrest the human breast cancer cells (Cram et al., 2001).
The indole ring system is planar and both ethoxycarbonyl groups adopt extended conformation as can be seen from the torsion angles C17—O3—C18—C19 [169.7 (2)°], C18—O3—C17—C16 [-177.6 (2)°], C21A/C21B—O5—C20—C16 [-165.5 (4)° /170.9 (5)°] and C20—O5—C21A/C21B—C22A/C22B [-105.2 (6)° / -176.8 (5)°]. The sum of bond angles around N1 [359.96°] indicates that atom N1 exhibits sp2 hybridization (Beddoes et al., 1986). In the tert-butoxycarbonyl group, the three C—C bond lengths lie between 1.501 (3) Å and 1.507 (3) Å, while the three tert-butyl C—C—C angles are in the range 110.6 (2)°–113.1 (2)°, indicating a slight opening up from the ideal tetrahedral value.
In the crystal structure, the molecules form R22(16) dimers through paired C23—H23C···O6 hydrogen bonds (Bernstein et al., 1995). A π-π stacking interaction is observed between pyrrole rings of moloecules at (x, y, z) and (2 - x, -y, -z), with a centroid to centroid distance of 3.5916 (9) Å.