(E)-2-(Furan-2-yl­methyl­idene)-8-methyl-2,3,4,9-tetra­hydro-1H-carbazol-1-one

R Archana; E Yamuna; K J Rajendra Prasad; A Thiruvalluvar; R J Butcher

doi:10.1107/S1600536810045599

. 2010 Nov 13;66(Pt 12):o3145. doi: 10.1107/S1600536810045599

(E)-2-(Furan-2-ylmethylidene)-8-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one

R Archana ^a, E Yamuna ^b, K J Rajendra Prasad ^b, A Thiruvalluvar ^a,^*, R J Butcher ^c

PMCID: PMC3011638 PMID: 21589444

Abstract

In the title molecule, C₁₈H₁₅NO₂, the carbazole unit is not planar [maximum deviation from mean plane = 0.236 (2) Å]. The pyrrole ring makes dihedral angles of 1.21 (10) and 16.74 (12)° with the benzene and the furan rings, respectively. The cyclohexene ring adopts a half-chair conformation. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R ₂ ²(10) loops.

Related literature

For the synthesis of hetero-annulated carbazoles, see: Knölker & Reddy (2002 ▶). For the derivation of various hetero-annulated carbazoles, see: Sridharan et al. (2008 ▶); Danish & Rajendra Prasad (2004 ▶, 2005 ▶); Periyasami et al. (2008 ▶, 2009 ▶). For ring conformations, see: Cremer & Pople (1975 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₈H₁₅NO₂
M _r = 277.31
Orthorhombic,
a = 6.7353 (1) Å
b = 16.1393 (3) Å
c = 25.9549 (4) Å
V = 2821.38 (8) Å³
Z = 8
Cu Kα radiation
μ = 0.68 mm⁻¹
T = 295 K
0.44 × 0.28 × 0.12 mm

Data collection

Oxford Diffraction Xcalibur Ruby Gemini diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 ▶) T _min = 0.888, T _max = 1.000
6361 measured reflections
2736 independent reflections
2201 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.157
S = 1.05
2736 reflections
195 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810045599/si2306sup1.cif

e-66-o3145-sup1.cif^{(21.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810045599/si2306Isup2.hkl

e-66-o3145-Isup2.hkl^{(131.7KB, 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
N9—H9⋯O1ⁱ	0.89 (3)	2.01 (3)	2.8969 (19)	176 (2)

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Symmetry code: (i) Inline graphic .

Acknowledgments

RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.

supplementary crystallographic information

Comment

As a result of their significant potential as therapeutics, interest has grown in the development of methods for the efficient and rapid synthesis of the derivatives of various hetero-annulated carbazoles especially because the current methods, which involve multi-step reactions, lower yields, longer reaction times, and high cost of palladium (Knölker & Reddy (2002)) are unsatisfactory. Herein, therefore, we report the easily accessible synthon (E)-2-(furan-2-yl methylene)-8-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one to derive various hetero-annulated carbazoles (Sridharan et al., (2008); Danish & Rajendra Prasad (2004, 2005); Periyasami et al., (2008, 2009)).

In the title molecule (Scheme I, Fig. 1), C₁₈H₁₅NO₂, the carbazole unit is not planar. The pyrrole ring makes dihedral angles of 1.21 (10)° and 16.74 (12)° with the benzene and the furan rings respectively. The cyclohexene ring adopts a half-chair conformation. The puckering parameters (Cremer & Pople, 1975) are q2=0.232 (2) Å, q3=-0.153 (2) Å, Q=0.278 (2) Å, θ=123.4 (4)° and φ=322.6 (5)°. Intermolecular N9—H9···O1 hydrogen bonds form a R₂²(10) (Bernstein et al., 1995) ring in the crystal structure (Table 1, Fig. 2).

Experimental

An equimolar mixture of 8-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one (0.995 g, 0.005 mol) and furan-2-carbaldehyde (0.41 ml, 0.005 mol) was treated with 25 ml of a 5% ethanolic potassium hydroxide solution and stirred for 6 h at room temperature. The product precipitated as a yellow crystalline mass, was filtered off and washed with 50% ethanol. A further crop of condensation product was obtained on neutralization with acetic acid and dilution with water. The product was recrystallized from methanol to yield 90% (1.246 g) of the title compound. The pure compound was recrystallized from EtOAc.