3-Methyl-1-tosyl-1H-indole-2-carbaldehyde

Priyamvada Pradeep; Sanaz Khorasani; Charles B de Koning; Manuel A Fernandes

doi:10.1107/S160053681205180X

. 2013 Jan 12;69(Pt 2):o219. doi: 10.1107/S160053681205180X

3-Methyl-1-tosyl-1H-indole-2-carbaldehyde

Priyamvada Pradeep ^a, Sanaz Khorasani ^a, Charles B de Koning ^a, Manuel A Fernandes ^a,^*

PMCID: PMC3569754 PMID: 23424500

Abstract

The title indole derivative, C₁₇H₁₅NO₃S, crystallizes with two independent molecules in the asymmetric unit. The benzene ring of the tosyl group is almost perpedicular to the indole ring in both molecules, with interplanar angles of 82.60 (5)° and 81.82 (6)°. The two molecules are, as a consequence, able to form an almost centrosymmetric non-bonded dimer, in which the molecules are linked by pairs of C—H⋯π interactions. The crystal structure displays a three-dimensional network of C—H⋯O interactions. A π–π interaction occurs between inversion-related indole rings with a centroid–centroid distance of 3.6774 (16) Å and an interplanar angle of 1.53 (15)°. This interaction leads to a stacking of molecules along the a axis.

Related literature

For studies of reactions involving indoles, see: Pathak et al. (2006 ▶); Pelly et al. (2005 ▶); Sharma et al. (2010 ▶). It is interesting to note that the reaction used to synthesize this product has been reported to be ineffective when carried out in acetone, see: Kothandaraman et al. (2011 ▶).

Experimental

Crystal data

C₁₇H₁₅NO₃S
M _r = 313.36
Triclinic,
a = 8.4276 (2) Å
b = 13.0126 (3) Å
c = 14.2522 (4) Å
α = 79.968 (2)°
β = 79.794 (2)°
γ = 83.505 (2)°
V = 1509.25 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 173 K
0.28 × 0.25 × 0.05 mm

Data collection

Bruker APEX-II CCD diffractometer
16378 measured reflections
5936 independent reflections
3668 reflections with I > 2σ(I)
R _int = 0.051

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.126
S = 1.01
5936 reflections
401 parameters
H-atom parameters constrained
Δρ_max = 0.31 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT-NT (Bruker, 2005 ▶); data reduction: SAINT-NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶) and SCHAKAL-99 (Keller, 1999 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and PLATON (Spek, 2009) ▶.

Supplementary Material

Click here for additional data file.^{(38KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681205180X/fy2083sup1.cif

e-69-0o219-sup1.cif^{(38KB, cif)}

Click here for additional data file.^{(284.7KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681205180X/fy2083Isup2.hkl

e-69-0o219-Isup2.hkl^{(284.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg3, Cg4, Cg5 and Cg6 are the centroids of the C11B–C16B, C3B–C8B, C3A–C8A and C11A–C16A rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C16B—H16B⋯O1B ⁱ	0.95	2.50	3.153 (3)	126
C12A—H12A⋯O1A ⁱⁱ	0.95	2.48	3.218 (3)	134
C16A—H16A⋯O2A ⁱⁱⁱ	0.95	2.52	3.220 (3)	131
C17B—H17F⋯O2B ^iv	0.98	2.53	3.396 (4)	147
C8A—H8A⋯Cg3	0.95	2.87	3.804 (3)	167
C9A—H9C⋯Cg4	0.98	2.80	3.726 (4)	158
C9B—H9D⋯Cg5	0.98	2.65	3.576 (4)	158
C9B—H9E⋯Cg6	0.98	2.95	3.755 (4)	140

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

This work was supported by the University of the Witwatersrand and National Research Foundation, Pretoria.

supplementary crystallographic information

Comment

Indoles are heterocyclic compounds containing a pyrrole ring fused to a benzene ring at the a,b positions. Indole is an important biological heterocyclic system as it is present, for example, in the amino acid tryptophan. As a consequence, it is a biologically accepted pharmacophore. Derivatives possess a broad spectrum of biological activities (Sharma et al., 2010), for example indomethacin (a non-steroidal anti-inflammatory drug) would fit in this class. The title compound is part of our continuing efforts to synthesize indole-based derivatives (Pathak et al., 2006; Pelly et al. 2005)

The title organic compound (Fig. 1) crystallizes in the space group P-1 with two independent molecules in the asymmetric unit. The aromatic moieties [indole (C1—C8 and N1) and tosyl group (C11—C17)] in each molecule are orientated with respect to each other at an angle of 82.60 (5)° and 81.82 (6)° in molecules A and B, respectively. The crystal structure contains C—H···O, C—H···π and π···π interactions. The π···π interaction occurs over a Cg1···Cg2 distance of 3.6774 (16) Å between two indole rings [Cg1 = N1A—C1A—C2A—C3A—C4A; Cg2 = N1B—C1B—C2B—C3B—C4B] with an interplanar angle of 1.53 (15) ° (Fig. 2). This leads to a stacking of molecules along the a axis. The structure contains several C—H···π interactions which are shown in Fig. 2. A layer of A and B molecules along the (001) plane is given in Fig. 3 showing the relative orientation of the A and B molecules in the layer. Geometrical details for the C—H···π and C—H···O interactions are given in Table 1.

Experimental

The title compound was synthesized by reaction of iodine (942 mg, 3.70 mmol) with N-(2-(2-hydroxybut-3-yn-2-yl)phenyl-4-methyl)benzenesulfonamide (584.9 mg,1.854 mmol) in the presence of methanol (20 ml) as a solvent. The resulting mixture was stirred for 6 h at 60°C. The reaction was then quenched by adding a saturated aq. solution of Na₂S₂O₃ and extracted with ethyl acetate (3×20 mL). The combined organics were then washed with aq. NaHCO₃ and brine, and dried over anhydrous Na₂SO₄. After removal of solvent, the left over residue was purified by flash column chromatography, with silica gel using a mixture of hexane and ethyl acetate (20:1) to give 3-methyl-1-tosyl-1H-indole-2-carbaldehyde (329 mg, 86%). Single crystals were grown by slow evaporation from dichloromethane.