Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807032412/fl2137sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807032412/fl2137Isup2.hkl |
CCDC reference: 657693
To a refluxing solution of 2,3-dibromomethyl-1-(phenylsulfonyl)indole (294 mg, 0.664 mmol) (Mohanakrishnan & Srinivasan, 1995) and K2CO3 (312 mg, 2.25 mmol) in tetrahydrofuran (10 ml) was added a solution of tert-butylamine (90 µL, 0.80 mmol) in tetrahydrofuran (15 ml) slowly via addition funnel. After 10 h, the reaction mixture was cooled to rt, and the opaque solution was filtered through a Celite pad with ethyl acetate rinses. The resulting combined yellow solution was concentrated in vacuo to yield a pale yellow solid which was purified by column chromatography (2:1 hexanes: ethyl acetate) to yield (I) as a white solid (161 mg, 68%): m.p. 457–458 K. As (I) was unstable toward oxidation, an elemental analysis was not attempted. Recrystallization from hexane–dichloromethane (3:1) yielded crystals that were suitable for X-ray crystallography.
The H atoms were included in the riding model approximation with C—H = 0.93–0.97 Å, and with Uiso(H) = 1.19–1.20Ueq(C).
The title compound, C20H22N2O2S, was synthesized as a precursor to the corresponding pyrrolo[3,4-b]indole as a stable synthetic analogue of indole-2,3-quinodimethane. The tert-butyl group was chosen to block oxidation of the pyrrolidine ring by adventitious oxygen, a side-reaction that is more pronounced with the isopropyl analogue discussed in the preceding paper (Kishbaugh et al., 2007). The X-ray crystallographic analysis confirms the molecular structure and atom connectivity for (I) that we had proposed for this compound based on NMR spectroscopy and chemical reactions (Kishbaugh & Gribble, 2002).
The tertiary butyl group has one methyl group (C18) bisecting the molecular plane with torsion angles of 65.2 (5)° for C1—N2—C17—C18 and -67.5 (5)° for C2—N2—C17—C18. The other two methyl groups, C19 and C20, adopt a gauche butane arrangement with the pyrrolidine methylene groups C3 and C1, respectively.
For the synthesis of the title compound and related chemistry, see: Gribble (2003); Gribble et al. (2005); Roy, Kishbaugh et al. (2007); Kishbaugh & Gribble (2002); Mohanakrishnan & Srinivasan (1995). For a related structure, see: Kishbaugh et al. (2007).
Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1994); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: CrystalStructure (Rigaku/MSC, 2005); 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: CrystalStructure.
Fig. 1. Molecular structure of (I) showing atom labelling and 50% probability displacement ellipsoids. |
C20H22N2O2S | Dx = 1.326 Mg m−3 |
Mr = 354.46 | Mo Kα radiation, λ = 0.71069 Å |
Orthorhombic, Pbca | Cell parameters from 20 reflections |
a = 18.113 (5) Å | θ = 10.4–13.2° |
b = 16.140 (9) Å | µ = 0.20 mm−1 |
c = 12.146 (8) Å | T = 296 K |
V = 3551 (3) Å3 | Prism, yellow |
Z = 8 | 0.50 × 0.50 × 0.40 mm |
F(000) = 1504 |
Rigaku AFC-6S diffractometer | 1736 reflections with I > 2σ(I) |
Radiation source: normal-focus sealed tube | Rint = 0.000 |
Graphite monochromator | θmax = 27.5°, θmin = 2.3° |
ω/2θ scans | h = 0→23 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→20 |
Tmin = 0.907, Tmax = 0.925 | l = −15→0 |
4059 measured reflections | 3 standard reflections every 150 reflections |
4059 independent reflections | intensity decay: none |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.062 | H-atom parameters constrained |
wR(F2) = 0.283 | w = 1/[σ2(Fo2) + (0.1437P)2 + 2.0864P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max < 0.001 |
4059 reflections | Δρmax = 0.38 e Å−3 |
228 parameters | Δρmin = −0.41 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0011 (9) |
C20H22N2O2S | V = 3551 (3) Å3 |
Mr = 354.46 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 18.113 (5) Å | µ = 0.20 mm−1 |
b = 16.140 (9) Å | T = 296 K |
c = 12.146 (8) Å | 0.50 × 0.50 × 0.40 mm |
Rigaku AFC-6S diffractometer | 1736 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.000 |
Tmin = 0.907, Tmax = 0.925 | 3 standard reflections every 150 reflections |
4059 measured reflections | intensity decay: none |
4059 independent reflections |
R[F2 > 2σ(F2)] = 0.062 | 0 restraints |
wR(F2) = 0.283 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.38 e Å−3 |
4059 reflections | Δρmin = −0.41 e Å−3 |
228 parameters |
Experimental. 1H (CD2Cl2) δ 7.98 (dd, 1H, 1, 7 Hz), 7.83-7.87 (m, 2H), 7.43-7.58 (m, 3H), 7.19-7.35 (m, 3H), 4.30 (m, 2H), 3.96 (m, 2H), 1.18 (s, 9H); 13C (CDCl3) δ 139.7, 138.5, 134.0, 129.6, 128.9, 126.9, 126.1, 123.9, 123.8, 122.9, 119.4, 114.3, 54.1, 48.8, 46.7, 26.3; IR (film) λmax 3061, 2962, 1447, 1364, 1216, 1171, 1089, 995, 913, 748, 720, 682 cm-1; UV (EtOH) λmax 258 nm. |
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 | ||
S1 | 0.25733 (7) | −0.01040 (8) | 0.61347 (10) | 0.0343 (4) | |
O1 | 0.21803 (19) | 0.0451 (2) | 0.5441 (3) | 0.0461 (10) | |
O2 | 0.2272 (2) | −0.0358 (3) | 0.7161 (3) | 0.0517 (11) | |
N1 | 0.3376 (2) | 0.0366 (3) | 0.6408 (3) | 0.0347 (10) | |
N2 | 0.4291 (2) | 0.1561 (2) | 0.4210 (3) | 0.0325 (10) | |
C1 | 0.3561 (3) | 0.1342 (3) | 0.4654 (4) | 0.0386 (13) | |
H5 | 0.3264 | 0.1050 | 0.4115 | 0.046* | |
H6 | 0.3295 | 0.1828 | 0.4907 | 0.046* | |
C2 | 0.4876 (3) | 0.1369 (3) | 0.5033 (4) | 0.0380 (12) | |
H7 | 0.5045 | 0.1866 | 0.5405 | 0.046* | |
H8 | 0.5295 | 0.1096 | 0.4692 | 0.046* | |
C3 | 0.4484 (3) | 0.0802 (3) | 0.5810 (4) | 0.0313 (11) | |
C4 | 0.4609 (3) | 0.0343 (3) | 0.6813 (4) | 0.0327 (12) | |
C5 | 0.5234 (3) | 0.0151 (3) | 0.7450 (5) | 0.0408 (13) | |
H1 | 0.5703 | 0.0311 | 0.7222 | 0.049* | |
C6 | 0.5136 (4) | −0.0279 (4) | 0.8423 (5) | 0.0486 (15) | |
H3 | 0.5545 | −0.0399 | 0.8859 | 0.058* | |
C7 | 0.4448 (3) | −0.0533 (4) | 0.8758 (4) | 0.0453 (14) | |
H4 | 0.4400 | −0.0823 | 0.9416 | 0.054* | |
C8 | 0.3825 (3) | −0.0368 (3) | 0.8138 (4) | 0.0402 (13) | |
H2 | 0.3362 | −0.0544 | 0.8371 | 0.048* | |
C9 | 0.3908 (3) | 0.0064 (3) | 0.7163 (4) | 0.0318 (11) | |
C10 | 0.3770 (3) | 0.0794 (3) | 0.5584 (4) | 0.0310 (11) | |
C11 | 0.2819 (3) | −0.0994 (3) | 0.5378 (4) | 0.0335 (12) | |
C12 | 0.2947 (3) | −0.0918 (4) | 0.4257 (5) | 0.0465 (14) | |
H9 | 0.2884 | −0.0412 | 0.3904 | 0.056* | |
C13 | 0.3169 (4) | −0.1611 (4) | 0.3675 (6) | 0.0621 (19) | |
H10 | 0.3267 | −0.1565 | 0.2925 | 0.075* | |
C14 | 0.3247 (4) | −0.2362 (4) | 0.4185 (7) | 0.065 (2) | |
H11 | 0.3395 | −0.2823 | 0.3783 | 0.078* | |
C15 | 0.3106 (4) | −0.2435 (4) | 0.5302 (7) | 0.0639 (19) | |
H12 | 0.3155 | −0.2946 | 0.5648 | 0.077* | |
C16 | 0.2893 (3) | −0.1747 (4) | 0.5906 (5) | 0.0474 (15) | |
H13 | 0.2800 | −0.1792 | 0.6657 | 0.057* | |
C17 | 0.4340 (3) | 0.2364 (3) | 0.3643 (4) | 0.0362 (12) | |
C18 | 0.4207 (4) | 0.3109 (3) | 0.4420 (5) | 0.0521 (15) | |
H14 | 0.3690 | 0.3239 | 0.4434 | 0.062* | |
H15 | 0.4479 | 0.3580 | 0.4158 | 0.062* | |
H16 | 0.4370 | 0.2970 | 0.5149 | 0.062* | |
C19 | 0.5108 (3) | 0.2429 (4) | 0.3128 (6) | 0.0565 (17) | |
H17 | 0.5442 | 0.2676 | 0.3646 | 0.068* | |
H18 | 0.5083 | 0.2766 | 0.2478 | 0.068* | |
H19 | 0.5281 | 0.1886 | 0.2935 | 0.068* | |
C20 | 0.3769 (3) | 0.2372 (4) | 0.2715 (5) | 0.0551 (17) | |
H20 | 0.3990 | 0.2163 | 0.2052 | 0.066* | |
H21 | 0.3602 | 0.2929 | 0.2595 | 0.066* | |
H22 | 0.3357 | 0.2029 | 0.2915 | 0.066* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0316 (7) | 0.0367 (7) | 0.0347 (7) | −0.0061 (5) | 0.0014 (6) | −0.0008 (6) |
O1 | 0.037 (2) | 0.044 (2) | 0.058 (2) | 0.0048 (17) | −0.0071 (19) | −0.0025 (19) |
O2 | 0.048 (2) | 0.064 (3) | 0.042 (2) | −0.016 (2) | 0.0144 (19) | −0.003 (2) |
N1 | 0.039 (2) | 0.035 (2) | 0.031 (2) | −0.0063 (19) | −0.0016 (19) | 0.0039 (18) |
N2 | 0.037 (2) | 0.032 (2) | 0.028 (2) | −0.0021 (18) | −0.0027 (18) | 0.0041 (18) |
C1 | 0.043 (3) | 0.037 (3) | 0.037 (3) | −0.007 (2) | −0.008 (2) | 0.007 (2) |
C2 | 0.038 (3) | 0.038 (3) | 0.038 (3) | −0.002 (2) | 0.004 (2) | 0.002 (2) |
C3 | 0.036 (3) | 0.028 (3) | 0.030 (3) | −0.002 (2) | −0.003 (2) | −0.002 (2) |
C4 | 0.044 (3) | 0.025 (2) | 0.030 (3) | 0.002 (2) | −0.004 (2) | −0.004 (2) |
C5 | 0.035 (3) | 0.042 (3) | 0.045 (3) | 0.004 (2) | −0.002 (3) | 0.001 (3) |
C6 | 0.060 (4) | 0.045 (4) | 0.041 (3) | 0.007 (3) | −0.015 (3) | 0.004 (3) |
C7 | 0.063 (4) | 0.045 (3) | 0.029 (3) | 0.005 (3) | −0.005 (3) | 0.011 (3) |
C8 | 0.050 (3) | 0.037 (3) | 0.033 (3) | −0.007 (3) | 0.004 (3) | 0.001 (2) |
C9 | 0.039 (3) | 0.026 (2) | 0.030 (3) | −0.003 (2) | −0.001 (2) | −0.004 (2) |
C10 | 0.034 (3) | 0.026 (2) | 0.033 (3) | −0.007 (2) | −0.004 (2) | −0.003 (2) |
C11 | 0.028 (3) | 0.035 (3) | 0.037 (3) | −0.006 (2) | −0.001 (2) | 0.002 (2) |
C12 | 0.054 (4) | 0.043 (3) | 0.043 (3) | −0.006 (3) | 0.005 (3) | 0.000 (3) |
C13 | 0.067 (4) | 0.067 (5) | 0.052 (4) | −0.009 (4) | 0.014 (3) | −0.021 (3) |
C14 | 0.054 (4) | 0.052 (4) | 0.091 (6) | 0.002 (3) | −0.006 (4) | −0.025 (4) |
C15 | 0.056 (4) | 0.042 (4) | 0.094 (6) | −0.006 (3) | −0.025 (4) | 0.002 (4) |
C16 | 0.043 (3) | 0.046 (3) | 0.054 (4) | −0.010 (3) | −0.009 (3) | 0.012 (3) |
C17 | 0.045 (3) | 0.033 (3) | 0.030 (3) | −0.001 (2) | 0.004 (2) | 0.008 (2) |
C18 | 0.066 (4) | 0.036 (3) | 0.054 (4) | −0.004 (3) | 0.004 (3) | 0.001 (3) |
C19 | 0.051 (4) | 0.062 (4) | 0.056 (4) | −0.006 (3) | 0.006 (3) | 0.020 (3) |
C20 | 0.061 (4) | 0.055 (4) | 0.050 (4) | −0.006 (3) | −0.007 (3) | 0.023 (3) |
S1—O1 | 1.421 (4) | C8—C9 | 1.383 (7) |
S1—O2 | 1.422 (4) | C8—H2 | 0.9300 |
S1—N1 | 1.673 (4) | C11—C16 | 1.380 (7) |
S1—C11 | 1.762 (5) | C11—C12 | 1.387 (7) |
N1—C10 | 1.411 (6) | C12—C13 | 1.382 (8) |
N1—C9 | 1.417 (6) | C12—H9 | 0.9300 |
N2—C17 | 1.470 (6) | C13—C14 | 1.370 (10) |
N2—C1 | 1.472 (6) | C13—H10 | 0.9300 |
N2—C2 | 1.490 (7) | C14—C15 | 1.386 (10) |
C1—C10 | 1.483 (7) | C14—H11 | 0.9300 |
C1—H5 | 0.9700 | C15—C16 | 1.386 (9) |
C1—H6 | 0.9700 | C15—H12 | 0.9300 |
C2—C3 | 1.494 (7) | C16—H13 | 0.9300 |
C2—H7 | 0.9700 | C17—C19 | 1.528 (8) |
C2—H8 | 0.9700 | C17—C20 | 1.530 (7) |
C3—C10 | 1.322 (6) | C17—C18 | 1.548 (7) |
C3—C4 | 1.443 (7) | C18—H14 | 0.9600 |
C4—C5 | 1.406 (7) | C18—H15 | 0.9600 |
C4—C9 | 1.412 (7) | C18—H16 | 0.9600 |
C5—C6 | 1.382 (8) | C19—H17 | 0.9600 |
C5—H1 | 0.9300 | C19—H18 | 0.9600 |
C6—C7 | 1.374 (8) | C19—H19 | 0.9600 |
C6—H3 | 0.9300 | C20—H20 | 0.9600 |
C7—C8 | 1.382 (8) | C20—H21 | 0.9600 |
C7—H4 | 0.9300 | C20—H22 | 0.9600 |
O1—S1—O2 | 120.7 (3) | C3—C10—N1 | 110.6 (4) |
O1—S1—N1 | 105.5 (2) | C3—C10—C1 | 113.7 (4) |
O2—S1—N1 | 106.9 (2) | N1—C10—C1 | 134.7 (4) |
O1—S1—C11 | 109.3 (2) | C16—C11—C12 | 121.2 (5) |
O2—S1—C11 | 108.6 (3) | C16—C11—S1 | 120.0 (4) |
N1—S1—C11 | 104.7 (2) | C12—C11—S1 | 118.8 (4) |
C10—N1—C9 | 106.4 (4) | C13—C12—C11 | 118.7 (6) |
C10—N1—S1 | 121.4 (3) | C13—C12—H9 | 120.7 |
C9—N1—S1 | 124.4 (3) | C11—C12—H9 | 120.7 |
C17—N2—C1 | 116.0 (4) | C14—C13—C12 | 120.9 (6) |
C17—N2—C2 | 117.1 (4) | C14—C13—H10 | 119.5 |
C1—N2—C2 | 110.0 (4) | C12—C13—H10 | 119.5 |
N2—C1—C10 | 101.1 (4) | C13—C14—C15 | 120.0 (7) |
N2—C1—H5 | 111.5 | C13—C14—H11 | 120.0 |
C10—C1—H5 | 111.5 | C15—C14—H11 | 120.0 |
N2—C1—H6 | 111.5 | C14—C15—C16 | 120.1 (6) |
C10—C1—H6 | 111.5 | C14—C15—H12 | 120.0 |
H5—C1—H6 | 109.4 | C16—C15—H12 | 120.0 |
N2—C2—C3 | 102.3 (4) | C11—C16—C15 | 119.1 (6) |
N2—C2—H7 | 111.3 | C11—C16—H13 | 120.4 |
C3—C2—H7 | 111.3 | C15—C16—H13 | 120.4 |
N2—C2—H8 | 111.3 | N2—C17—C19 | 107.9 (4) |
C3—C2—H8 | 111.3 | N2—C17—C20 | 108.2 (4) |
H7—C2—H8 | 109.2 | C19—C17—C20 | 108.3 (5) |
C10—C3—C4 | 108.9 (4) | N2—C17—C18 | 112.9 (4) |
C10—C3—C2 | 109.9 (4) | C19—C17—C18 | 109.7 (5) |
C4—C3—C2 | 140.6 (5) | C20—C17—C18 | 109.7 (5) |
C5—C4—C9 | 119.1 (5) | C17—C18—H14 | 109.5 |
C5—C4—C3 | 134.7 (5) | C17—C18—H15 | 109.5 |
C9—C4—C3 | 106.1 (4) | H14—C18—H15 | 109.5 |
C6—C5—C4 | 118.6 (5) | C17—C18—H16 | 109.5 |
C6—C5—H1 | 120.7 | H14—C18—H16 | 109.5 |
C4—C5—H1 | 120.7 | H15—C18—H16 | 109.5 |
C7—C6—C5 | 121.3 (5) | C17—C19—H17 | 109.5 |
C7—C6—H3 | 119.4 | C17—C19—H18 | 109.5 |
C5—C6—H3 | 119.4 | H17—C19—H18 | 109.5 |
C6—C7—C8 | 121.5 (5) | C17—C19—H19 | 109.5 |
C6—C7—H4 | 119.3 | H17—C19—H19 | 109.5 |
C8—C7—H4 | 119.3 | H18—C19—H19 | 109.5 |
C7—C8—C9 | 118.3 (5) | C17—C20—H20 | 109.5 |
C7—C8—H2 | 120.8 | C17—C20—H21 | 109.5 |
C9—C8—H2 | 120.8 | H20—C20—H21 | 109.5 |
C8—C9—C4 | 121.2 (5) | C17—C20—H22 | 109.5 |
C8—C9—N1 | 130.8 (5) | H20—C20—H22 | 109.5 |
C4—C9—N1 | 107.9 (4) | H21—C20—H22 | 109.5 |
Experimental details
Crystal data | |
Chemical formula | C20H22N2O2S |
Mr | 354.46 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 296 |
a, b, c (Å) | 18.113 (5), 16.140 (9), 12.146 (8) |
V (Å3) | 3551 (3) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.20 |
Crystal size (mm) | 0.50 × 0.50 × 0.40 |
Data collection | |
Diffractometer | Rigaku AFC-6S |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.907, 0.925 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4059, 4059, 1736 |
Rint | 0.000 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.062, 0.283, 1.06 |
No. of reflections | 4059 |
No. of parameters | 228 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.38, −0.41 |
Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1994), MSC/AFC Diffractometer Control Software, CrystalStructure (Rigaku/MSC, 2005), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), CrystalStructure.
The title compound, C20H22N2O2S, was synthesized as a precursor to the corresponding pyrrolo[3,4-b]indole as a stable synthetic analogue of indole-2,3-quinodimethane. The tert-butyl group was chosen to block oxidation of the pyrrolidine ring by adventitious oxygen, a side-reaction that is more pronounced with the isopropyl analogue discussed in the preceding paper (Kishbaugh et al., 2007). The X-ray crystallographic analysis confirms the molecular structure and atom connectivity for (I) that we had proposed for this compound based on NMR spectroscopy and chemical reactions (Kishbaugh & Gribble, 2002).
The tertiary butyl group has one methyl group (C18) bisecting the molecular plane with torsion angles of 65.2 (5)° for C1—N2—C17—C18 and -67.5 (5)° for C2—N2—C17—C18. The other two methyl groups, C19 and C20, adopt a gauche butane arrangement with the pyrrolidine methylene groups C3 and C1, respectively.