6-Bromo-2-[(E)-thio­phen-2-yl­methyl­idene]-2,3,4,9-tetra­hydro-1H-carbazol-1-one

R Velmurugan; M Sekar; A V Vijayasankar; P Ramesh; M N Ponnuswamy

doi:10.1107/S1600536811046551

. 2011 Nov 12;67(Pt 12):o3271. doi: 10.1107/S1600536811046551

6-Bromo-2-[(E)-thiophen-2-ylmethylidene]-2,3,4,9-tetrahydro-1H-carbazol-1-one

R Velmurugan ^a, M Sekar ^a, A V Vijayasankar ^b, P Ramesh ^c, M N Ponnuswamy ^c,^*

PMCID: PMC3238929 PMID: 22199778

Abstract

In the title compound, C₁₇H₁₂BrNOS, the cyclohexene ring deviates only slightly from planarity (r.m.s. deviation for non-H atoms = 0.047 Å). In the crystal, the molecules are linked into centrosymmetric R ₂ ²(10) dimers via pairs of N—H⋯O hydrogen bonds. The thiophene ring is disordered over two positions rotated by 180° and with a site-occupation factor of 0.843 (4) for the major occupied site.

Related literature

For the biological activity of carbazole derivatives, see: Magnus et al. (1992 ▶); Abraham (1975 ▶); Saxton (1983 ▶); Phillipson & Zenk (1980 ▶); Bergman & Pelcman (1990 ▶); Bonesi et al. (2004 ▶); Chakraborty et al. (1965 ▶); Kirtikar & Basu (1933 ▶); Chakraborty et al. (1973 ▶); Savini et al. (2004 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For asymmetry parameters, see: Nardelli (1983 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₇H₁₂BrNOS
M _r = 358.25
Monoclinic,
a = 13.8655 (5) Å
b = 6.3081 (3) Å
c = 17.4583 (7) Å
β = 103.666 (2)°
V = 1483.76 (11) Å³
Z = 4
Mo Kα radiation
μ = 2.91 mm⁻¹
T = 296 K
0.21 × 0.17 × 0.16 mm

Data collection

Bruker SMART APEX CCD detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.558, T _max = 0.628
12158 measured reflections
4487 independent reflections
1953 reflections with I > 2σ(I)
R _int = 0.044

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.148
S = 0.85
4487 reflections
191 parameters
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT-Plus (Bruker, 1998 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811046551/bt5684sup1.cif

e-67-o3271-sup1.cif^{(23.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811046551/bt5684Isup2.hkl

e-67-o3271-Isup2.hkl^{(219.9KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811046551/bt5684Isup3.cml

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
N1—H1⋯O1ⁱ	0.88	2.00	2.804 (4)	151

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the Solid State Unit, Indian Institute of Science, Bangalore, India, for the data collection and and Dr A. Chandramohan, Post Graduate and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore, for his valuable suggestions.

supplementary crystallographic information

Comment

Carbazole alkaloids obtained from naturally occurring sources have been the subject of extensive research, mainly because of their widespread applications in traditional medicine (Bergman & Pelcman, 1990; Bonesi et al., 2004; Chakraborty et al., 1965; Kirtikar & Basu, 1933). Tetrahydrocarbazole systems are present in the framework of a number of indole-type alkaloids of biological interest (Magnus et al., 1992; Abraham, 1975; Saxton, 1983; Phillipson et al., 1980). These types of compounds possess significant antibiotic, anti-carcinogenic, antiviral and anti-inflammatory properties (Chakraborty et al., 1973). The thiophene derivatives possess the antimicrobial activity (Savini et al., 2004). Against this background and to ascertain the molecular structure and conformation, the X-ray crystal structure determination of the title compound has been carried out.

The ORTEP plot of the molecule is shown in Fig. 1. The cyclohexene ring in the carbazole ring system adopts envelope conformation with the puckering parameters (Cremer & Pople, 1975) and the asymmetry parameters (Nardelli, 1983) are: q₂=0.126 (5) Å, q₃ = 0.050 (4) Å, φ₂ = 102.0 (2)° and Δ_s(C10 & C13)= 4.4 (5)°. Thiophene ring in the molecule is planar conformation. The sum of the bond angles around N1 [359.3°] is in accordance with sp² hybridization.

The molecules at (x, y, z) and (-x + 2, -y + 1, -z) are linked by N1—H1···O1 hydrogen bonds into a cyclic centrosymmetric R₂²(14) dimer.

Experimental

The mixed aldol condensation reaction of 6-bromo-1-oxo-1,2,3, 4-tetrahydrocarbazole reacted with thiophene-2-carbaldehyde in the presence of alcoholic KOH, afforded a single product, substituted 6-bromo-2- thiofuran-2-ylmethylene-2,3,4,9-tetrahydro-carbazol-1-one. This was purified by using column chromatography over silica gel (mesh 60–80). During elution of the column with petroleum ether (60–80°C) and ethyl acetate [1:2] mixture, a yellowish solid was obtained. The crystals of the title compound suitable for single XRD analysis were obtained by the slow evaporation method using the solvent mixture ethyl acetate and acetone (8:2) at room temperature.