Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807028243/ez2083sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807028243/ez2083Isup2.hkl |
CCDC reference: 654971
A mixture of N-methylindole (10 mmol) and I2 (1 mmol) was stirred in acetonitrile (30 ml) at room temperature for a few s. After completion of the reaction (TLC, < 1 min), the mixture was treated with aqueous Na2S2O3 solution (5%, 30 ml). The product was extracted with ethyl acetate (3 × 30 ml). The combined organic layer was dried with anhydrous sodium sulfate, and purified by column chromatography (ethyl acetate:petroleum ether = 1:20) to afford the title compound (85% yield). Recrystallization by slow evaporation of a methanol solution was carried out to obtain good, diffraction quality crystals.
All H atoms were positioned geometrically and allowed to ride on their respective parent atoms, with C—H = 0.93, 0.96, 0.97 or 0.98 Å and Uiso(H) = 1.2 or 1.5 Ueq(C).
Indole has potentially reactive sites for a variety of chemical reactions to generate molecular diversity (Farhanullah et al., 2004). Indole derivatives, either natural or synthetic products, have been widely studied because of their therapeutic importance (Sundberg, 1996). Indoles are known to dimerize and trimerize in acidic media (Noland et al., 1960), and the derivatives of the indole dimer, i.e. a series of 1-imidoyl-2-(2- and 3-indolyl)indolines, are found to present potential diuretic activity (Wu et al., 1972). The title compound (I) was synthesized by dimerization of N-methylindole in the presence of iodine as a catalyst. Herein we report the crystal structure of (I).
The molecular structure of (I) is shown in Fig.1. A l l bond distances and angles are normal. The length of the bond linking the indole and the indoline rings (C2—C10) is 1.486 (3) Å. The indoline ring adopts an envelope conformation with atom C10 deviating from the N2/C11/C12/C17 plane by 0.501 (3) Å. The indole ring and the indoline ring are approximately perpendicular, and the dihedral angle between them is 86.30 (3)°.
For related literature on indole derivatives, see: Farhanullah et al. (2004); Noland & Hammer (1960); Sundberg (1996); Wu et al. (1972).
Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.
Fig. 1. A perspective view of (I) with atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. |
C18H18N2 | Z = 2 |
Mr = 262.34 | F(000) = 280 |
Triclinic, P1 | Dx = 1.212 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.3843 (15) Å | Cell parameters from 3267 reflections |
b = 10.282 (2) Å | θ = 3.1–27.5° |
c = 10.757 (2) Å | µ = 0.07 mm−1 |
α = 65.54 (3)° | T = 298 K |
β = 75.14 (3)° | Block, colorless |
γ = 84.22 (3)° | 0.51 × 0.49 × 0.23 mm |
V = 718.6 (3) Å3 |
Bruker SMART CCD APEXII diffractometer | 3267 independent reflections |
Radiation source: fine-focus sealed tube | 2203 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.017 |
Detector resolution: 8.40 pixels mm-1 | θmax = 27.5°, θmin = 3.1° |
ω scans | h = −9→9 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −13→13 |
Tmin = 0.964, Tmax = 0.984 | l = −13→13 |
7121 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)] = 0.063 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.215 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.1209P)2 + 0.0915P] where P = (Fo2 + 2Fc2)/3 |
3267 reflections | (Δ/σ)max < 0.001 |
181 parameters | Δρmax = 0.58 e Å−3 |
0 restraints | Δρmin = −0.29 e Å−3 |
C18H18N2 | γ = 84.22 (3)° |
Mr = 262.34 | V = 718.6 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.3843 (15) Å | Mo Kα radiation |
b = 10.282 (2) Å | µ = 0.07 mm−1 |
c = 10.757 (2) Å | T = 298 K |
α = 65.54 (3)° | 0.51 × 0.49 × 0.23 mm |
β = 75.14 (3)° |
Bruker SMART CCD APEXII diffractometer | 3267 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2203 reflections with I > 2σ(I) |
Tmin = 0.964, Tmax = 0.984 | Rint = 0.017 |
7121 measured reflections |
R[F2 > 2σ(F2)] = 0.063 | 0 restraints |
wR(F2) = 0.215 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.58 e Å−3 |
3267 reflections | Δρmin = −0.29 e Å−3 |
181 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 | ||
N1 | 0.0594 (2) | 0.54541 (17) | 0.62999 (18) | 0.0532 (5) | |
N2 | −0.2976 (3) | 0.2855 (2) | 1.07571 (19) | 0.0608 (5) | |
C1 | −0.1060 (3) | 0.5440 (2) | 0.7237 (2) | 0.0528 (5) | |
H1A | −0.1762 | 0.6248 | 0.7220 | 0.063* | |
C2 | −0.1544 (3) | 0.4082 (2) | 0.8201 (2) | 0.0478 (5) | |
C3 | −0.0081 (3) | 0.3184 (2) | 0.78479 (19) | 0.0441 (5) | |
C4 | 0.0237 (3) | 0.1719 (2) | 0.8403 (2) | 0.0527 (5) | |
H4A | −0.0607 | 0.1108 | 0.9186 | 0.063* | |
C5 | 0.1830 (3) | 0.1188 (2) | 0.7771 (3) | 0.0644 (6) | |
H5A | 0.2053 | 0.0210 | 0.8135 | 0.077* | |
C6 | 0.3100 (3) | 0.2088 (3) | 0.6604 (3) | 0.0678 (7) | |
H6A | 0.4167 | 0.1700 | 0.6209 | 0.081* | |
C7 | 0.2826 (3) | 0.3533 (3) | 0.6016 (2) | 0.0586 (6) | |
H7A | 0.3671 | 0.4129 | 0.5221 | 0.070* | |
C8 | 0.1232 (3) | 0.4075 (2) | 0.66545 (19) | 0.0457 (5) | |
C9 | 0.1532 (4) | 0.6710 (2) | 0.5147 (2) | 0.0681 (7) | |
H9A | 0.0801 | 0.7542 | 0.5128 | 0.102* | |
H9B | 0.1671 | 0.6616 | 0.4276 | 0.102* | |
H9C | 0.2746 | 0.6805 | 0.5273 | 0.102* | |
C10 | −0.3284 (3) | 0.3675 (2) | 0.9342 (2) | 0.0514 (5) | |
H10A | −0.3935 | 0.4557 | 0.9334 | 0.062* | |
C11 | −0.4692 (4) | 0.2706 (3) | 0.9273 (3) | 0.0717 (7) | |
H11A | −0.5534 | 0.3262 | 0.8688 | 0.086* | |
H11B | −0.4053 | 0.2011 | 0.8921 | 0.086* | |
C12 | −0.5719 (3) | 0.1998 (2) | 1.0790 (2) | 0.0596 (6) | |
C13 | −0.7391 (4) | 0.1275 (3) | 1.1416 (3) | 0.0749 (7) | |
H13A | −0.8123 | 0.1184 | 1.0870 | 0.090* | |
C14 | −0.7986 (4) | 0.0678 (3) | 1.2871 (3) | 0.0731 (7) | |
H14A | −0.9110 | 0.0172 | 1.3301 | 0.088* | |
C15 | −0.6936 (3) | 0.0830 (2) | 1.3672 (3) | 0.0687 (7) | |
H15A | −0.7364 | 0.0435 | 1.4645 | 0.082* | |
C16 | −0.5242 (3) | 0.1559 (2) | 1.3072 (2) | 0.0622 (6) | |
H16A | −0.4531 | 0.1665 | 1.3624 | 0.075* | |
C17 | −0.4639 (3) | 0.2130 (2) | 1.1609 (2) | 0.0554 (6) | |
C18 | −0.1963 (4) | 0.3514 (3) | 1.1257 (3) | 0.0840 (8) | |
H18A | −0.1844 | 0.2871 | 1.2180 | 0.126* | |
H18B | −0.2603 | 0.4360 | 1.1298 | 0.126* | |
H18C | −0.0740 | 0.3767 | 1.0638 | 0.126* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0550 (10) | 0.0429 (9) | 0.0495 (9) | −0.0051 (7) | −0.0071 (8) | −0.0087 (7) |
N2 | 0.0512 (10) | 0.0688 (12) | 0.0529 (10) | 0.0022 (9) | −0.0069 (8) | −0.0189 (9) |
C1 | 0.0551 (12) | 0.0434 (10) | 0.0558 (11) | 0.0070 (9) | −0.0126 (9) | −0.0178 (9) |
C2 | 0.0487 (11) | 0.0434 (10) | 0.0451 (10) | 0.0047 (8) | −0.0064 (8) | −0.0156 (8) |
C3 | 0.0453 (10) | 0.0429 (10) | 0.0402 (9) | 0.0012 (8) | −0.0059 (8) | −0.0156 (8) |
C4 | 0.0558 (12) | 0.0440 (10) | 0.0503 (11) | 0.0023 (9) | −0.0062 (9) | −0.0155 (9) |
C5 | 0.0671 (14) | 0.0476 (12) | 0.0725 (15) | 0.0120 (10) | −0.0087 (12) | −0.0255 (11) |
C6 | 0.0541 (13) | 0.0698 (15) | 0.0773 (15) | 0.0100 (11) | −0.0001 (11) | −0.0388 (13) |
C7 | 0.0468 (11) | 0.0680 (14) | 0.0539 (12) | −0.0071 (10) | 0.0031 (9) | −0.0247 (10) |
C8 | 0.0456 (10) | 0.0462 (10) | 0.0426 (9) | −0.0014 (8) | −0.0082 (8) | −0.0163 (8) |
C9 | 0.0785 (16) | 0.0528 (13) | 0.0565 (13) | −0.0198 (11) | −0.0123 (12) | −0.0036 (10) |
C10 | 0.0492 (11) | 0.0502 (11) | 0.0475 (10) | 0.0091 (9) | −0.0044 (9) | −0.0187 (9) |
C11 | 0.0630 (14) | 0.0657 (15) | 0.0731 (15) | −0.0067 (12) | 0.0096 (12) | −0.0286 (12) |
C12 | 0.0640 (13) | 0.0521 (12) | 0.0594 (12) | 0.0009 (10) | −0.0056 (11) | −0.0247 (10) |
C13 | 0.0754 (16) | 0.0698 (16) | 0.0752 (16) | −0.0182 (13) | −0.0058 (14) | −0.0278 (13) |
C14 | 0.0671 (15) | 0.0553 (13) | 0.0749 (16) | −0.0123 (11) | 0.0024 (13) | −0.0132 (12) |
C15 | 0.0663 (15) | 0.0488 (12) | 0.0572 (13) | 0.0060 (11) | 0.0047 (11) | −0.0011 (10) |
C16 | 0.0575 (13) | 0.0578 (12) | 0.0536 (12) | 0.0109 (10) | −0.0093 (10) | −0.0099 (10) |
C17 | 0.0459 (11) | 0.0416 (10) | 0.0581 (12) | 0.0104 (8) | 0.0020 (9) | −0.0108 (9) |
C18 | 0.0743 (17) | 0.102 (2) | 0.0733 (17) | −0.0125 (16) | −0.0119 (14) | −0.0337 (16) |
N1—C1 | 1.367 (3) | C9—H9B | 0.9600 |
N1—C8 | 1.374 (3) | C9—H9C | 0.9600 |
N1—C9 | 1.449 (3) | C10—C11 | 1.546 (3) |
N2—C18 | 1.384 (3) | C10—H10A | 0.9800 |
N2—C17 | 1.395 (3) | C11—C12 | 1.504 (3) |
N2—C10 | 1.468 (3) | C11—H11A | 0.9700 |
C1—C2 | 1.365 (3) | C11—H11B | 0.9700 |
C1—H1A | 0.9300 | C12—C13 | 1.369 (3) |
C2—C3 | 1.430 (3) | C12—C17 | 1.383 (3) |
C2—C10 | 1.486 (3) | C13—C14 | 1.388 (4) |
C3—C4 | 1.391 (3) | C13—H13A | 0.9300 |
C3—C8 | 1.412 (3) | C14—C15 | 1.359 (4) |
C4—C5 | 1.383 (3) | C14—H14A | 0.9300 |
C4—H4A | 0.9300 | C15—C16 | 1.385 (3) |
C5—C6 | 1.386 (3) | C15—H15A | 0.9300 |
C5—H5A | 0.9300 | C16—C17 | 1.396 (3) |
C6—C7 | 1.370 (3) | C16—H16A | 0.9300 |
C6—H6A | 0.9300 | C18—H18A | 0.9600 |
C7—C8 | 1.392 (3) | C18—H18B | 0.9600 |
C7—H7A | 0.9300 | C18—H18C | 0.9600 |
C9—H9A | 0.9600 | ||
C1—N1—C8 | 108.25 (16) | N2—C10—C2 | 114.55 (17) |
C1—N1—C9 | 125.9 (2) | N2—C10—C11 | 101.59 (18) |
C8—N1—C9 | 125.8 (2) | C2—C10—C11 | 116.85 (18) |
C18—N2—C17 | 120.3 (2) | N2—C10—H10A | 107.8 |
C18—N2—C10 | 117.3 (2) | C2—C10—H10A | 107.8 |
C17—N2—C10 | 107.50 (18) | C11—C10—H10A | 107.8 |
C2—C1—N1 | 111.00 (19) | C12—C11—C10 | 101.8 (2) |
C2—C1—H1A | 124.5 | C12—C11—H11A | 111.4 |
N1—C1—H1A | 124.5 | C10—C11—H11A | 111.4 |
C1—C2—C3 | 105.94 (17) | C12—C11—H11B | 111.4 |
C1—C2—C10 | 125.18 (19) | C10—C11—H11B | 111.4 |
C3—C2—C10 | 128.86 (18) | H11A—C11—H11B | 109.3 |
C4—C3—C8 | 118.78 (18) | C13—C12—C17 | 119.9 (2) |
C4—C3—C2 | 134.08 (18) | C13—C12—C11 | 131.8 (3) |
C8—C3—C2 | 107.13 (17) | C17—C12—C11 | 108.3 (2) |
C5—C4—C3 | 118.9 (2) | C12—C13—C14 | 119.6 (3) |
C5—C4—H4A | 120.5 | C12—C13—H13A | 120.2 |
C3—C4—H4A | 120.5 | C14—C13—H13A | 120.2 |
C4—C5—C6 | 121.1 (2) | C15—C14—C13 | 120.4 (2) |
C4—C5—H5A | 119.4 | C15—C14—H14A | 119.8 |
C6—C5—H5A | 119.4 | C13—C14—H14A | 119.8 |
C7—C6—C5 | 121.7 (2) | C14—C15—C16 | 121.5 (2) |
C7—C6—H6A | 119.1 | C14—C15—H15A | 119.2 |
C5—C6—H6A | 119.1 | C16—C15—H15A | 119.2 |
C6—C7—C8 | 117.4 (2) | C15—C16—C17 | 117.6 (2) |
C6—C7—H7A | 121.3 | C15—C16—H16A | 121.2 |
C8—C7—H7A | 121.3 | C17—C16—H16A | 121.2 |
N1—C8—C7 | 130.23 (19) | C12—C17—N2 | 110.0 (2) |
N1—C8—C3 | 107.68 (17) | C12—C17—C16 | 121.0 (2) |
C7—C8—C3 | 122.08 (19) | N2—C17—C16 | 128.9 (2) |
N1—C9—H9A | 109.5 | N2—C18—H18A | 109.5 |
N1—C9—H9B | 109.5 | N2—C18—H18B | 109.5 |
H9A—C9—H9B | 109.5 | H18A—C18—H18B | 109.5 |
N1—C9—H9C | 109.5 | N2—C18—H18C | 109.5 |
H9A—C9—H9C | 109.5 | H18A—C18—H18C | 109.5 |
H9B—C9—H9C | 109.5 | H18B—C18—H18C | 109.5 |
C8—N1—C1—C2 | −0.5 (2) | C18—N2—C10—C11 | −171.3 (2) |
C9—N1—C1—C2 | −179.3 (2) | C17—N2—C10—C11 | −32.1 (2) |
N1—C1—C2—C3 | 0.5 (2) | C1—C2—C10—N2 | −125.8 (2) |
N1—C1—C2—C10 | −178.07 (19) | C3—C2—C10—N2 | 56.0 (3) |
C1—C2—C3—C4 | −179.1 (2) | C1—C2—C10—C11 | 115.6 (3) |
C10—C2—C3—C4 | −0.6 (4) | C3—C2—C10—C11 | −62.6 (3) |
C1—C2—C3—C8 | −0.3 (2) | N2—C10—C11—C12 | 30.0 (2) |
C10—C2—C3—C8 | 178.2 (2) | C2—C10—C11—C12 | 155.37 (19) |
C8—C3—C4—C5 | 0.2 (3) | C10—C11—C12—C13 | 163.0 (3) |
C2—C3—C4—C5 | 178.9 (2) | C10—C11—C12—C17 | −18.9 (2) |
C3—C4—C5—C6 | 0.0 (4) | C17—C12—C13—C14 | −0.1 (4) |
C4—C5—C6—C7 | −0.8 (4) | C11—C12—C13—C14 | 177.8 (2) |
C5—C6—C7—C8 | 1.3 (4) | C12—C13—C14—C15 | 1.2 (4) |
C1—N1—C8—C7 | 178.9 (2) | C13—C14—C15—C16 | −0.9 (4) |
C9—N1—C8—C7 | −2.2 (4) | C14—C15—C16—C17 | −0.4 (3) |
C1—N1—C8—C3 | 0.2 (2) | C13—C12—C17—N2 | 177.8 (2) |
C9—N1—C8—C3 | 179.1 (2) | C11—C12—C17—N2 | −0.6 (2) |
C6—C7—C8—N1 | −179.5 (2) | C13—C12—C17—C16 | −1.3 (3) |
C6—C7—C8—C3 | −1.0 (3) | C11—C12—C17—C16 | −179.6 (2) |
C4—C3—C8—N1 | 179.05 (18) | C18—N2—C17—C12 | 159.2 (2) |
C2—C3—C8—N1 | 0.0 (2) | C10—N2—C17—C12 | 21.5 (2) |
C4—C3—C8—C7 | 0.3 (3) | C18—N2—C17—C16 | −21.8 (3) |
C2—C3—C8—C7 | −178.73 (19) | C10—N2—C17—C16 | −159.6 (2) |
C18—N2—C10—C2 | 61.8 (3) | C15—C16—C17—C12 | 1.5 (3) |
C17—N2—C10—C2 | −158.96 (18) | C15—C16—C17—N2 | −177.4 (2) |
Experimental details
Crystal data | |
Chemical formula | C18H18N2 |
Mr | 262.34 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 298 |
a, b, c (Å) | 7.3843 (15), 10.282 (2), 10.757 (2) |
α, β, γ (°) | 65.54 (3), 75.14 (3), 84.22 (3) |
V (Å3) | 718.6 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.51 × 0.49 × 0.23 |
Data collection | |
Diffractometer | Bruker SMART CCD APEXII |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.964, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7121, 3267, 2203 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.063, 0.215, 1.09 |
No. of reflections | 3267 |
No. of parameters | 181 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.58, −0.29 |
Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SAINT, SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL (Sheldrick, 1997b), SHELXTL.
Indole has potentially reactive sites for a variety of chemical reactions to generate molecular diversity (Farhanullah et al., 2004). Indole derivatives, either natural or synthetic products, have been widely studied because of their therapeutic importance (Sundberg, 1996). Indoles are known to dimerize and trimerize in acidic media (Noland et al., 1960), and the derivatives of the indole dimer, i.e. a series of 1-imidoyl-2-(2- and 3-indolyl)indolines, are found to present potential diuretic activity (Wu et al., 1972). The title compound (I) was synthesized by dimerization of N-methylindole in the presence of iodine as a catalyst. Herein we report the crystal structure of (I).
The molecular structure of (I) is shown in Fig.1. A l l bond distances and angles are normal. The length of the bond linking the indole and the indoline rings (C2—C10) is 1.486 (3) Å. The indoline ring adopts an envelope conformation with atom C10 deviating from the N2/C11/C12/C17 plane by 0.501 (3) Å. The indole ring and the indoline ring are approximately perpendicular, and the dihedral angle between them is 86.30 (3)°.