6,6-[Ethyl­enebis(sulfanediyl)]-2-(2-methoxy­ethyl)-1,2,3,4,5,6-hexa­hydro-1,5-methano-1H-azocino[4,3-b]indol-3-one

Barış Tercan; Fatma Yüksel; Süleyman Patır; Tuncer Hökelek

doi:10.1107/S1600536810015941

. 2010 May 8;66(Pt 6):o1275–o1276. doi: 10.1107/S1600536810015941

6,6-[Ethylenebis(sulfanediyl)]-2-(2-methoxyethyl)-1,2,3,4,5,6-hexahydro-1,5-methano-1H-azocino[4,3-b]indol-3-one

Barış Tercan ^a, Fatma Yüksel ^b, Süleyman Patır ^c, Tuncer Hökelek ^d,^*

PMCID: PMC2979528 PMID: 21579376

Abstract

The title compound, C₁₉H₂₂N₂O₂S₂, consists of a tetracyclic ring system containing an azocine skeleton with methoxyethyl and dithiolane groups as substituents. The benzene and five-membered N-heterocyclic rings are nearly coplanar, making a dihedral angle of 0.81 (12)°. The dithiolane ring adopts an envelope conformation. Intermolecular N—H⋯O hydrogen-bonding and weak C—H⋯π interactions are present in the crystal structure.

Related literature

For general background to the hexahydro-1,5-methano-azocino[4,3-b]indole core structure, a synthetic precursor for most of the pentacyclic and tetracyclic indole alkaloids of biological interest, see: Hesse (2002 ▶); Bosch & Bonjoch (1988 ▶); Saxton (1983 ▶). For related structures, see: Hökelek et al. (2004 ▶, 2006 ▶, 2007 ▶); Tercan et al. (2010 ▶); Uludağ et al. (2006 ▶).

Experimental

Crystal data

C₁₉H₂₂N₂O₂S₂
M _r = 374.53
Monoclinic,
a = 11.2233 (3) Å
b = 15.4228 (5) Å
c = 12.3027 (4) Å
β = 121.267 (2)°
V = 1820.23 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.31 mm⁻¹
T = 294 K
0.11 × 0.11 × 0.09 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.85, T _max = 0.97
13979 measured reflections
3203 independent reflections
2765 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.057
wR(F ²) = 0.159
S = 1.04
3203 reflections
279 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.10 e Å⁻³
Δρ_min = −0.56 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); 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 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810015941/xu2755sup1.cif

e-66-o1275-sup1.cif^{(21.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015941/xu2755Isup2.hkl

e-66-o1275-Isup2.hkl^{(154KB, hkl)}

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

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

Cg1 is the centroid of the C7a/C8/C9/C10/C11/C11a ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N7—H7⋯O1ⁱ	0.82 (4)	2.06 (4)	2.832 (4)	157 (3)
C17—H17A⋯Cg1ⁱⁱ	0.96	2.89	3.545 (9)	127

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

supplementary crystallographic information

Comment

The hexahydro-1,5-methano-azocino[4,3-b]indole core structure can be considered to be synthetic precursor for most of the pentacyclic and tetracyclic indole alkaloids of biological interests (Hesse, 2002; Bosch & Bonjoch, 1988; Saxton, 1983), such as akuminicine and uleine. Most of them have the pentacyclic ring system as a common element and include a large group of naturally occuring compounds such as strychnine, a consulvant poison, and uleine alkaloids.

The structures of tricyclic, tetracyclic and pentacyclic ring systems with different substituents of azocino[4,3-b]indole core have been determined, previously. These include N-(2-benzyloxyethyl)-4,7-dimethyl-6-(1,3-dithiolan- 2yl)-1,2,3,4,5,6-hexahydro-1,5-methano-2-azocino[4,3-b]indole-2-one, (II) (Hökelek et al., 2004), 12-ethyl-2-methyl-6,6-ethylenedithio-1,2,3,4,5,6 -hexahydro-1,5-methano-2-azocino[4,3-b]indole-3-one, (III) (Uludağ et al., 2006), 4-ethyl-6,6-ethylenedithio-2-(2-methoxymethyl)-7-methoxymethylene-2, 3,4,5,6,7-hexahydro-1,5-methano-1H-azocino[4,3-b]indole-3-one, (IV) (Hökelek et al., 2006), 2-(2,2-dimethoxyethyl)-3-oxo-1,2,3,4,5,6 -hexahydro-1,5-methano-7H-azocino[4,3-b]indole, (V) (Hökelek et al., 2007) and 2-ethyl-6,6-ethylenedisulfanediyl-7-methoxymethyl-1,2,3,4,5,6-hexahydro -1,5-methanoazocino[4,3-b]indol-3-one, (VI) (Tercan et al., 2010). The present study was undertaken to ascertain the crystal structure of the title compound, (I).

The molecule of the title compound, (I), (Fig. 1) consists of a tetracyclic ring system containing an azocino skeleton with methoxyethyl and dithiolane groups as substituents at positions N2 and 6, respectively. The bonds N7—C6a [1.368 (4) Å] and N7—C7a [1.374 (4) Å] agree well with those in compounds (II) [1.392 (8) and 1.370 (8) Å], (IV) [1.393 (4) and 1.386 (5) Å], (V) [1.377 (3) and 1.376 (3) Å] and (VI) [1.398 (3) and 1.387 (3) Å]. The absolute configurations of C1 and C5 are S and S (Fig. 1). The S atoms of the dithiolane ring have electron-releasing properties, but the N atom at position 7 and the O atom attached to C3 have electron-withdrawing properties, leading to some changes in the bond lengths and angles of the carbazole skeleton.

An examination of the deviations from the least-squares planes through individual rings shows that rings A (C7a/C8/C9/C10/C11/C11a) and B (N7/C7a/C11a/C11b/C6a) are planar. They are also coplanar with a dihedral angle of A/B = 0.81 (12)°. Rings C (C1/C11b/C6a/C6/C5/C14), D (C1/N2/C3/C4/C5/C14) and E (C6/S1/S2/C12/C13) are, of course, not planar. Atom C14 deviates from the planes of F(C1/C5/C6/C6a/C11b) and G (C1/N2/C3/C4/C5) by 0.705 (4) Å and 0.737 (4) Å, respectively where the dihedral angle between planes of F and G is F/G = 69.64 (12)°. On the other hand, the dihedral angles between the plane of H (C1/C5/C14) and the planes of F and G are 54.18 (24)° and 56.47 (21)°, respectively. The conformation of ring E is an envelope, with atom C13 at the flap position, 0.583 (6) Å from the mean plane through the other four atoms.

In the crystal structure, intermolecular N—H···O hydrogen bonds (Table 1) link the molecules into chains nearly parallel to b-axis (Fig. 2), in which they may be effective in the stabilization of the structure. A weak C—H···π interaction also occurs (Table 1).

Experimental

The title compound, (I), was prepared from 2,3-dichloro-5,6-dicyano-p -benzoquinone (0.68 g, 3.00 mmol) and N-(methoxyethyl)-(2,3,4,9-tetra -hydrospiro-[1H-carbazole-1,2'-(1,3)dithiolane]-2-yl)-2-acetamide (1.00 g, 2.68 mmol) in THF (35 ml). The mixture was stirred at room temperature for 4 h under nitrogen atmosphere, and then poured into sodium hydroxide solution (100 ml, 10%). After extraction with dichloromethane (50 ml), the organic layer was dried with Na₂SO₄ and the solvent was evaporated. The residue was purified by silicagel chromatography using triethylamine, acetone and ethyl acetate (7:25:75) and crystallized from ethyl acetate/diethyl ether (2:1) (yield; 0.87 g, 88%), m.p. 445 K.