4-Methyl-7,8,9,10-tetra­hydro­cyclo­hepta­[b]indol-6(5H)-one

M Sridharan; K J Rajendra Prasad; A Thomas Gunaseelan; A Thiruvalluvar; R J Butcher

doi:10.1107/S1600536809007429

. 2009 Mar 6;65(Pt 4):o698. doi: 10.1107/S1600536809007429

4-Methyl-7,8,9,10-tetrahydrocyclohepta[b]indol-6(5H)-one

M Sridharan ^a, K J Rajendra Prasad ^a, A Thomas Gunaseelan ^b, A Thiruvalluvar ^b,^*, R J Butcher ^c

PMCID: PMC2968932 PMID: 21582438

Abstract

In the title compound, C₁₄H₁₅NO, the seven-membered ring exhibits a slightly distorted twist-boat conformation. The pyrrole ring forms a dihedral angle of 1.44 (10)° with the fused benzene ring. N—H⋯O hydrogen bonds form a centrosymmetric dimer and weak C—H⋯π interactions are also found in the crystal structure.

Related literature

For a related crystal structure, see: Sridharan et al. (2008 ▶).

Experimental

Crystal data

C₁₄H₁₅NO
M _r = 213.27
Monoclinic,
a = 9.6731 (4) Å
b = 10.0924 (5) Å
c = 11.8328 (6) Å
β = 103.397 (5)°
V = 1123.74 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 295 K
0.55 × 0.45 × 0.26 mm

Data collection

Oxford Diffraction Gemini R diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008 ▶) T _min = 0.936, T _max = 1.000 (expected range = 0.917–0.980)
9586 measured reflections
3772 independent reflections
2044 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.077
wR(F ²) = 0.253
S = 1.04
3772 reflections
150 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.57 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 ▶); data reduction: CrysAlis RED; 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: PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809007429/wn2312sup1.cif

e-65-0o698-sup1.cif^{(19.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809007429/wn2312Isup2.hkl

e-65-0o698-Isup2.hkl^{(181.2KB, 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
N5—H5⋯O6ⁱ	0.94 (3)	2.11 (3)	2.992 (2)	156.6 (19)
C10—H10A⋯Cg1ⁱⁱ	0.97	2.84	3.736 (2)	154
C14—H14C⋯Cg1ⁱⁱⁱ	0.96	2.86	3.621 (2)	137
C8—H8A⋯Cg2ⁱⁱ	0.97	2.87	3.830 (3)	173

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 is the centroid of the pyrrole ring and Cg2 is the centroid of the benzene ring.

Acknowledgments

We acknowledge the UGC, New Delhi, India, for the award of Major Research Project grant No. F.No.31-122/2005. MS thanks the UGC, New Delhi, India, for the award of research fellowship. AT thanks the UGC, New Delhi, India, for the award of a Minor Research Project [File No. MRP-2355/06(UGC-SERO), Link No. 2355, 10/01/2007]. RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.

supplementary crystallographic information

Comment

The title compound has been analysed as part of our crystallographic studies on cyclohept[b]indoles and their substituted analogues. Sridharan et al.(2008) have reported the X-ray crystal sructure of the related compound, 7,8,9,10-tetrahydro-2-methylcyclohepta[b]indol-6(5H)-one. In that paper, the seven-membered ring is stated to exhibit a slightly distorted envelope conformation.

In the title compound, C₁₄H₁₅NO (Fig. 1), the seven-membered ring exhibits a slightly distorted twist-boat conformation. The pyrrole ring forms a dihedral angle of 1.44 (10)° with the fused benzene ring.

N5—H5···O6(-x, -y, -z) hydrogen bonds form a centrosymmetric dimer. Furthermore, C10—H10A···π(1- x, -y, -z) and C14—H14C···π(1/2-x, -1/2+y, 1/2-z) interactions involving the pyrrole ring are present. Additionally, a C8—H8A···π(1-x, -y, -z) interaction involving the benzene ring are also found in the crystal structure.

Experimental

A solution of 2-(2-(1-methylphenyl)hydrazono)cycloheptanone (0.230 g, 0.001 mol) in a mixture of acetic acid (20 ml) and conc. hydrochloric acid (5 ml) was refluxed on an oil bath pre-heated to 398–403 K for 4 h. The reaction was monitored by TLC. After the completion of the reaction, the contents were cooled and poured into ice water with stirring. The separated brown solid was filtered and purified by passing through a column of silica gel and eluting with a petroleum ether-ethyl acetate (95:5 v/v) mixture to yield the title compound (0.140 g, 66%). This product was recrystallized using ethanol.