4-Methyl-9-[(4-methyl­phen­yl)sulfon­yl]thio­pyrano[3,4-b]indole-3(9H)-thione

Benjamin Dassonneville; Dieter Schollmeyer; Bernhard Witulski; Heiner Detert

doi:10.1107/S1600536810038201

. 2010 Sep 30;66(Pt 10):o2665. doi: 10.1107/S1600536810038201

4-Methyl-9-[(4-methylphenyl)sulfonyl]thiopyrano[3,4-b]indole-3(9H)-thione

Benjamin Dassonneville ^a, Dieter Schollmeyer ^a, Bernhard Witulski ^b, Heiner Detert ^a,^*

PMCID: PMC2983115 PMID: 21587636

Abstract

The title compound, C₁₉H₁₅NO₂S₃, is the first example of a dithia analogue of pyrano[3,4-b]indolone. The almost planar thiopyranoindolethione ring system (r.m.s. deviation for all non-H atoms = 0.030 Å) makes a dihedral angle of 80.70 (8)° with the p-tolyl ring. In the crystal, molecules are connected via C—H⋯O hydrogen bonds into two chains along the b axis. These chains are connected via π–π interactions between symmetry-related thiopyranoindolethione ring systems [centroid–centroid distance = 3.588 (1) Å].

Related literature

The title compound was synthesized as part of a larger project focusing on metal-catalysed transformations of tethered alkynyl-ynamides to carbazoles (Witulski & Alayrac, 2002 ▶) and to carbolines and other heteroannulated indoles (Nissen, 2008 ▶; Dassonneville, 2010 ▶). The reactivity of such an annulated thiopyranothione could be similar to the respective pyrano[3,4-b]indolone, well known as stable equivalents of indoloquinodimethanes (Plieninger et al., 1964 ▶) and valuable intermediates for the synthesis of various heteroannulated indoles, see, for example: Livadiotou et al. (2009 ▶).

Experimental

Crystal data

C₁₉H₁₅NO₂S₃
M _r = 385.50
Monoclinic,
a = 13.2530 (4) Å
b = 8.2423 (3) Å
c = 15.4500 (16) Å
β = 96.124 (3)°
V = 1678.05 (19) Å³
Z = 4
Cu Kα radiation
μ = 4.15 mm⁻¹
T = 193 K
0.60 × 0.10 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: numerical (de Meulenaer & Tompa, 1965 ▶) T _min = 0.42, T _max = 0.70
3167 measured reflections
3167 independent reflections
2714 reflections with I > 2σ(I)
3 standard reflections every 60 min intensity decay: 2%

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.102
S = 1.04
3167 reflections
228 parameters
H-atom parameters constrained
Δρ_max = 0.42 e Å⁻³
Δρ_min = −0.36 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: CORINC (Dräger & Gattow, 1971 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810038201/bt5362sup1.cif

e-66-o2665-sup1.cif^{(20.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810038201/bt5362Isup2.hkl

e-66-o2665-Isup2.hkl^{(155.4KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C21—H21⋯O15ⁱ	0.95	2.50	3.387 (3)	155
C22—H22⋯O16ⁱⁱ	0.95	2.59	3.116 (3)	116

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

supplementary crystallographic information

Comment

The title compound is formed via a rhodium-catalyzed [2 + 2+2] cycloaddition of a tethered alkynyl-ynamide and carbon disulfide. This unprecedented thiopyranoindolethione is obtained as dark violet crystals. The crystal structure of the title compound forms a network built by two chains along the b axis connected via hydrogen bonds C21—H21···O15 (2.50 Å) and C22—H21···O16 (2.59 Å). These chains are connected viaπ-π-interactions of two thiopyranoindolethiones related by a center of symmetry [distance between centroids 3.588 (1) Å].

The tricyclic framework is essentially planar with torsion angles of about 2.1 ° or less in the benzene moiety and up to 5.9 ° in the thiopyrane unit. The torsion angle around the biphenyl bond amounts to 176.0 (2) ° (C6,C7,C8,C13). Whereas the N—C bonds in the pyrrole ring are nearly identical, the C—C bond lengths increase in the sequence C2—C7, C7—C8, C8—C13. With 1.459 (3) Å, the biphenyl bond C7—C8 is significantly longer than C2—C3 (1.384 (3) Å) and C8—C13 (1.443 (3) Å). The thiocarbonyl bond length is about 1.668 (2) Å, much shorter than the C—S single bonds with 1.729 (2) Å (C10—S11) and 1.702 (2) Å (S11—C12). Due to steric repulsion of methyl and thiocarbonyl, the S24—C10—S11 bond angle is reduced to 113.07 (13) ° and the C10—S11—C12 bond angle is only 107.07 (11) °.

Experimental

The title compound was prepared from 2-(propynyl)-N-ethynyl-N-[(4-methylphenyl)sulfonyl)]benzenamine (Witulski & Alayrac, 2002)) as follows: Under Argon (Ar), BINAP (15.6 mg, 0.025 mmol, 10 mol%) and [RhCl(C₈H₁₄)₂]₂ (6.1 mg, 0.0087 mmol, 3.5 mol%) are dissolved in degassed CH₂Cl₂ (3.0 ml) in a Schlenk tube, and the mixture is stirred at room temperature for 5 min. H₂ is then introduced to the resulting solution. After stirring at room temperature for 0.5 h, the resulting solution is concentrated to dryness and the residue dissolved in dichloroethane (DCE) (3.0 ml). To this solution is added dropwise over 1 min a solution of the alkynyl-ynamide (0.25 mmol) and CS₂ (150 µL, 2.5 mmol, 10 equiv.) in DCE (5.0 ml). Undissolved substrate is dissolved by addition of DCE (2x1.0 ml), added to the solution and the mixture is heated to 353 K. After completion of the reaction (3 h, TLC), the solvent is removed and the residue is purified by column chromatography (Al₂O₃, Petroleum ether/Ethyl acetate, 95/5). Violet crystals of the title compound suitable for X-ray analysis were obtained by crystallization from CH₂Cl₂/Petroleum ether.