7H-1-Benzofuro[2,3-b]carbazole

R Panchatcharam; V Dhayalan; A K Mohanakrishnan; G Chakkaravarthi; V Manivannan

doi:10.1107/S1600536811039018

. 2011 Sep 30;67(Pt 10):o2797. doi: 10.1107/S1600536811039018

7H-1-Benzofuro[2,3-b]carbazole

R Panchatcharam ^a, V Dhayalan ^b, A K Mohanakrishnan ^b, G Chakkaravarthi ^c,^*, V Manivannan ^a,^*

PMCID: PMC3201223 PMID: 22058825

Abstract

In the title compound, C₁₈H₁₁NO, the carbazole and benzofuran rings are almost co-planar, making a dihedral angle of 3.31 (3)°. The crystal structure is stabilized by weak C—H⋯π interactions.

Related literature

For the biological activity of carbazole derivatives, see: Ramsewak et al. (1999 ▶); Diaz et al. (2002 ▶); Zhang et al. (2004 ▶). For the structures of closely related compounds, see: Chakkaravarthi et al. (2008a ▶,b ▶).

Experimental

Crystal data

C₁₈H₁₁NO
M _r = 257.28
Orthorhombic,
a = 26.087 (3) Å
b = 5.9585 (8) Å
c = 7.8146 (10) Å
V = 1214.7 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 295 K
0.24 × 0.22 × 0.20 mm

Data collection

Bruker Kappa APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.979, T _max = 0.983
6591 measured reflections
2700 independent reflections
2331 reflections with I > 2σ(I)
R _int = 0.022

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.084
S = 1.05
2700 reflections
182 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.13 e Å⁻³
Absolute structure: Flack (1983 ▶), 1086 Friedel pairs
Flack parameter: 0.2 (15)

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811039018/vm2122sup1.cif

e-67-o2797-sup1.cif^{(23.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811039018/vm2122Isup2.hkl

e-67-o2797-Isup2.hkl^{(129.9KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811039018/vm2122Isup3.cml

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

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

Cg2, Cg3 and Cg4 are the centroids of the N1/C1/C6/C7/C12, C1–C6 and C7–C12 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Cg4ⁱ	0.86	2.91	3.530 (2)	130
C5—H5⋯Cg2ⁱⁱ	0.93	2.70	3.449 (2)	138
C11—H11⋯Cg3ⁱ	0.93	2.79	3.526 (2)	137

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

Acknowledgments

The authors wish to acknowledge the SAIF, IIT, Madras, for the data collection.

supplementary crystallographic information

Comment

Carbazole derivatives exhibit anti-inflammatory and antimutagenic activities (Ramsewak et al., 1999). A carbazole ring is easily functionalized and covalently linked to other molecules (Diaz et al., 2002). This enables its use as a convenient building block for the design and synthesis of molecular glasses, which are widely studied as components of electroactive and photoactive materials (Zhang et al., 2004).

We herewith report the crystal structure of the title compound (Fig. 1). The geometric parameters agree well with those of similar reported structures (Chakkaravarthi et al., 2008a, 2008b). The benzofuran moiety (C9/C13-C18/O1/C10) is almost co-planar [dihedral angle 3.31 (3)°] with the carbazole ring (C1-C12/N1). The crystal structure is stabilized by weak intermolecular C-H···π interactions (Table 1).

Experimental

To a solution of tert-butyl-3-(2,2-di(ethoxycarbonyl)vinyl)-2-(bromomethyl) -1H-indole-1-carboxylate (0.5 g, 1.04 mmol) in dry 1,2-dichloroethane (15 mL), anhydrous ZnBr₂ (0.05 g, 0.22 mmol) and benzo[b]furan (0.13 mL, 1.27 mmol) were added. It was then stirred at room temperature for 2 h under N₂ atmosphere. The solvent was removed and the residue was quenched with ice-water (50 mL) containing 1 mL of conc. HCl, extracted with chloroform (2 x 10 mL) and dried (Na₂SO₄). Removal of solvent followed by flash column chromatography purification (n-hexane/ethyl acetate 80:20) led to the isolation of title compound as a colourless crystal suitable for X-Ray diffraction quality.