7,8,9,10-Tetra­hydro-2-methyl­cyclo­hepta­[b]indol-6(5H)-one

Sridharan, M.; Prasad, K.J.R.; Ngendahimana, A.; Zeller, M.

doi:10.1107/S1600536808016498

organic compounds

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ISSN: 2056-9890

Volume 64| Part 7| July 2008| Page o1207

doi:10.1107/S1600536808016498

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7,8,9,10-Tetrahydro-2-methylcyclohepta[b]indol-6(5H)-one

Makuteswaran Sridharan,^a Karnam J. Rajendra Prasad,^a Aimable Ngendahimana ^b and Matthias Zeller ^b ^*

^aDepartment of Chemistry, Bharathiar University, Coimbatore 641046, Tamil Nadu, India, and ^bDepartment of Chemistry, Youngstown State University, One University Plaza, Youngstown, OH 44555, USA
^*Correspondence e-mail: mzeller@cc.ysu.edu

(Received 15 May 2008; accepted 30 May 2008; online 7 June 2008)

The title compound, C₁₄H₁₅NO, was synthesized from 2-hydroxymethylenecycloheptanone via a Japp–Klingemann acid-catalyzed cyclization. The seven-membered ring exhibits a slightly distorted envelope conformation. N—H⋯O hydrogen bonds form a centrosymmetric dimer; C—H⋯O hydrogen bonds and π–π stacking interactions (the centers of the atoms involved in the stacking interaction are separated by 3.504 Å) give rise to another type of centrosymmetric dimer. In combination, these interactions create a stair-like chain of molecules that interacts only loosely with neighboring chains via van der Waals interactions and weak C—H⋯π contacts.

Related literature

For related literature on the synthesis, structure, anticancer and antidepressant activities, and toxicity of functionalized cyclohept[b]indoles, see: Cornec et al. (1998 ); Joseph et al. (1999 ); Kinnick et al. (2006 ); Humphrey & Kuethe (2006 , and references therein); Benoit et al. (2000 ); Kavitha & Rajendra Prasad (1999 , and references therein). Brameld et al. (2008 ) describe small-molecule conformational preferences derived from crystal structure data. Bernstein et al. (1995 ) present the use of the versatile graph-set analysis for the description of hydrogen bonds.

Experimental

Crystal data

C₁₄H₁₅NO
M_r = 213.27
Monoclinic, P 2₁ /n
a = 11.461 (3) Å
b = 6.5062 (19) Å
c = 14.459 (4) Å
β = 92.310 (4)°
V = 1077.3 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 100 (2) K
0.48 × 0.10 × 0.08 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS as implemented in APEX2; Bruker, 2008 ) T_min = 0.731, T_max = 0.993
9984 measured reflections
2652 independent reflections
1581 reflections with I > 2σ(I)
R_int = 0.081

Refinement

R[F² > 2σ(F²)] = 0.056
wR(F²) = 0.135
S = 1.00
2652 reflections
146 parameters
H-atom parameters constrained
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1ⁱ	0.88	2.09	2.890 (2)	150
C4—H4a⋯O1ⁱⁱ	0.99	2.59	3.211 (3)	121
C2—H2B⋯Cg1ⁱⁱⁱ	0.99	2.88	3.740 (2)	146
C5—H5b⋯C10^iv	0.99	2.90	3.794 (2)	151
Symmetry codes: (i) -x, -y, -z+2; (ii) x, y+1, z; (iii) -x, -y+1, -z+2; (iv) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ . Cg1 is the centroid of the C8–C13 ring.

Data collection: APEX2 (Bruker, 2008); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and Mercury (Macrae et al., 2006 ); software used to prepare material for publication: SHELXTL and Mercury.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808016498/fl2202sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808016498/fl2202Isup2.hkl

checkCIF report

Comment top

Development of new methods towards the synthesis of functionalized cyclohept[b]indoles is currently attractive to organic chemists due to the discovery of anti-cancer and anti-depressant activities associated with this system (Cornec et al., 1998; Joseph et al. 1999). Synthetic studies on the large family of indoles have been documented extensively because of their structural diversity and association with their wide spectrum of pharmacological potential. Synthetic approaches to prepare cyclohept[b]indoles have been described in the literature and examined for central nervous system activity and reported to be active as antidepressants (Kinnick et al., 2006; Humphrey & Kuethe, 2006, and references therein). The design of molecules that spontaneously organize into a helical architecture is of considerable interest because of their fascinating structural features as well as their potential applications. Benoit et al. (2000) have reported the toxicity and structure activity relationship of benzocyclohept[b]indoles and these were found to be potent anti-inflammatory and anti-cancer agents. Therefore, much effort has been directed towards the development of efficient methodologies for the construction of heterocyclo-fused cyclohept[b]indoles. Based on the interesting features of these compounds we reported the synthesis and utility of cyclohept[b]indoles and their substituted analogs (Kavitha & Rajendra Prasad 1999, and references therein).

Cyclization of 2-hydroxymethylenecycloheptanone under Japp-Klingemann conditions using acetic acid and HCl in a 4:1 ratio (Kent's reagent) as the catalyst furnished the title compound (Fig. 1). Details of the synthesis of the title compound were reported by Kavitha & Rajendra Prasad (1999). An ORTEP style representation of the title compound is given in Fig 2.

The sp² hybridized section of the molecule is essentially planar with an r.m.s. deviation from the mean plane of only 0.052 Å. Of the methylene carbon atoms C3 is deviates the most (0.786 (3) Å ) from this plane. Deviations for C2 and C4 are 0.252 (2) and -0.157 (3) Å, respectively. The seven membered ring thus is best described as having a slightly distorted envelope conformation (Brameld et al. 2008). All bond distances and angles in the structure of the title compound are in the expected ranges.

Via a pair of N—H···O hydrogen bonds the molecules form centrosymmetric dimers with an R²₂(10) graph set motif (Bernstein et al., 1995) in the solid state (Table 1, Fig. 3). The keto oxygen atom also acts as acceptor for a weaker C—H···O hydrogen bond from another neighboring molecule. The same neighboring molecule also acts as a partner for a π-π stacking interaction across an inversion center. The π moieties of these thus formed π-stacked dimers are slipped against each other and only the atoms C1, C6, C7 and C13 and their inversion symmetry related counterparts in the neighboring molecule are involved in the interaction of the π systems with a distance of about 3.5 Å between the planes (Fig. 3). Distances between the slipped centroids of the pyrrole rings are given in table 1. The main planes of the molecules are connected via the N—H···O and C—H···O hydrogen bonds and the π-π stacking interactions are all aligned roughly in parallel to each other. The two types of dimers created by the N—H···O and C—H···O interactions do each share one molecule, which extends the molecules held together via these strong to medium interactions into a flight of stairs like chain of molecules. Neighboring chains are only loosly connected via van der Waals interactions and weak C—H···π contacts (Table 1, Fig. 4).

Related literature top

For related literature on the synthesis, structure, anticancer and antidepressant activities, and toxicity of functionalized cyclohept[b]indoles, see: Cornec et al. (1998); Joseph et al. (1999); Kinnick et al. (2006); Humphrey & Kuethe (2006, and references therein); Benoit et al. (2000); Kavitha & Rajendra Prasad (1999, and references therein). Brameld et al. (2008) describe small-molecule conformational preferences derived from crystal structure data. Bernstein et al. (1995) present the use of the versatile graph-set analysis for the description of hydrogen bonds.

Experimental top

A solution of 2-(2-(4-methylphenyl)hydrazono)cycloheptanone (0.230 g, 0.001 mol) in a mixture of acetic acid (20 ml) and concentrated hydrochloric acid (5 ml) was heated to reflux on an oil bath pre-heated to 398–403 K for 2 h. The reaction was monitored by TLC. After completion of the reaction the contents were cooled and poured into icewater 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 mixture (95:5) to yieldthe title compound (171 mg, 80%). The product thus obtained was recrystallized using ethanol, m.p. 451–453 K.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: APEX2 (Bruker, 2008); data reduction: APEX2 (Bruker, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: 'SHELXTL (Sheldrick, 2008), Mercury (Macrae et al., 2006)'.

Figures top

	Fig. 1. Synthesis of the title compound
	Fig. 2. Thermal ellipsoid plot of one of the N—H···O bonded dimers with the atom labeling scheme. Displacement ellipsoids are shown at the 50% probability level, hydrogen atoms are shown as capped sticks.
	Fig. 3. Thermal ellipsoid plot of one of the π-stacked dimers. Red spheres are centers of π bonds involved in the π-stacking interactions, green dotted lines represent π···π contacts. Atom and bond styles as in Figure 2.
	Fig. 4. Packing view of the title crystal. Blue dotted lines represent N—H···O, C—H···O and C—H···π interactions. Green dotted lines are π···π contacts. Atom and bond styles as in Figure 2.

7,8,9,10-Tetrahydro-2-methylcyclohepta[b]indol-6(5H)-one top

Crystal data top

C₁₄H₁₅NO	F(000) = 456
M_r = 213.27	D_x = 1.315 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 11.461 (3) Å	Cell parameters from 1265 reflections
b = 6.5062 (19) Å	θ = 2.3–24.5°
c = 14.459 (4) Å	µ = 0.08 mm⁻¹
β = 92.310 (4)°	T = 100 K
V = 1077.3 (6) Å³	Plate, colourless
Z = 4	0.48 × 0.10 × 0.08 mm

Data collection top

Bruker SMART APEX CCD diffractometer	2652 independent reflections
Radiation source: fine-focus sealed tube	1581 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.081
ω scans	θ_max = 28.3°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS as implemented in APEX2; Bruker, 2008)	h = −15→15
T_min = 0.731, T_max = 0.993	k = −8→8
9984 measured reflections	l = −19→19

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.135	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.0596P)²] where P = (F_o² + 2F_c²)/3
2652 reflections	(Δ/σ)_max < 0.001
146 parameters	Δρ_max = 0.19 e Å⁻³
0 restraints	Δρ_min = −0.28 e Å⁻³

Crystal data top

C₁₄H₁₅NO	V = 1077.3 (6) Å³
M_r = 213.27	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 11.461 (3) Å	µ = 0.08 mm⁻¹
b = 6.5062 (19) Å	T = 100 K
c = 14.459 (4) Å	0.48 × 0.10 × 0.08 mm
β = 92.310 (4)°

Data collection top

Bruker SMART APEX CCD diffractometer	2652 independent reflections
Absorption correction: multi-scan (SADABS as implemented in APEX2; Bruker, 2008)	1581 reflections with I > 2σ(I)
T_min = 0.731, T_max = 0.993	R_int = 0.081
9984 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.056	0 restraints
wR(F²) = 0.135	H-atom parameters constrained
S = 1.00	Δρ_max = 0.19 e Å⁻³
2652 reflections	Δρ_min = −0.28 e Å⁻³
146 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.13517 (16)	0.2801 (3)	1.08139 (13)	0.0251 (4)
C2	0.21105 (17)	0.3796 (3)	1.15581 (13)	0.0284 (5)
H2A	0.2532	0.2688	1.1901	0.034*
H2B	0.1589	0.4463	1.1998	0.034*
C3	0.30146 (17)	0.5391 (3)	1.12828 (14)	0.0283 (5)
H3A	0.3491	0.5786	1.1841	0.034*
H3B	0.3544	0.4750	1.0841	0.034*
C4	0.24910 (17)	0.7329 (3)	1.08433 (13)	0.0280 (5)
H4A	0.1735	0.7618	1.1125	0.034*
H4B	0.3018	0.8500	1.0988	0.034*
C5	0.22933 (17)	0.7184 (3)	0.97993 (13)	0.0272 (5)
H5A	0.1874	0.8438	0.9586	0.033*
H5B	0.3066	0.7194	0.9516	0.033*
C6	0.16294 (15)	0.5361 (3)	0.94335 (13)	0.0241 (4)
C7	0.12670 (16)	0.3572 (3)	0.98660 (13)	0.0243 (4)
C8	0.06994 (16)	0.3237 (3)	0.83704 (13)	0.0244 (4)
C9	0.02351 (16)	0.2566 (3)	0.75210 (13)	0.0274 (5)
H9	−0.0126	0.1257	0.7455	0.033*
C10	0.03204 (16)	0.3877 (3)	0.67779 (14)	0.0287 (5)
H10	−0.0003	0.3463	0.6192	0.034*
C11	0.08746 (17)	0.5823 (3)	0.68576 (13)	0.0275 (5)
C12	0.13502 (16)	0.6455 (3)	0.77013 (14)	0.0271 (5)
H12	0.1734	0.7746	0.7759	0.032*
C13	0.12601 (16)	0.5160 (3)	0.84787 (13)	0.0245 (4)
C14	0.09470 (18)	0.7160 (3)	0.60049 (14)	0.0339 (5)
H14A	0.1211	0.8539	0.6187	0.051*
H14B	0.0175	0.7250	0.5691	0.051*
H14C	0.1502	0.6555	0.5584	0.051*
N1	0.07063 (13)	0.2311 (2)	0.92167 (10)	0.0253 (4)
H1	0.0402	0.1101	0.9332	0.030*
O1	0.07986 (11)	0.1233 (2)	1.10088 (9)	0.0300 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0207 (10)	0.0302 (10)	0.0251 (11)	0.0036 (8)	0.0076 (8)	0.0000 (8)
C2	0.0258 (10)	0.0348 (11)	0.0248 (11)	0.0005 (9)	0.0034 (9)	0.0010 (9)
C3	0.0240 (10)	0.0350 (11)	0.0258 (11)	0.0028 (9)	0.0002 (8)	−0.0005 (9)
C4	0.0233 (10)	0.0321 (11)	0.0286 (11)	0.0013 (9)	0.0017 (9)	−0.0010 (9)
C5	0.0260 (10)	0.0312 (11)	0.0246 (11)	−0.0014 (9)	0.0036 (9)	0.0008 (9)
C6	0.0183 (9)	0.0305 (10)	0.0237 (10)	0.0030 (8)	0.0032 (8)	−0.0015 (8)
C7	0.0196 (10)	0.0294 (10)	0.0241 (11)	0.0012 (8)	0.0037 (8)	−0.0021 (8)
C8	0.0182 (10)	0.0309 (10)	0.0245 (11)	0.0007 (8)	0.0050 (8)	0.0007 (9)
C9	0.0228 (10)	0.0337 (11)	0.0260 (11)	−0.0034 (9)	0.0049 (8)	−0.0016 (9)
C10	0.0206 (10)	0.0429 (12)	0.0230 (11)	−0.0005 (9)	0.0051 (8)	−0.0025 (9)
C11	0.0210 (10)	0.0380 (12)	0.0239 (11)	−0.0015 (9)	0.0048 (8)	0.0009 (9)
C12	0.0204 (10)	0.0327 (11)	0.0284 (11)	0.0000 (9)	0.0060 (8)	0.0019 (9)
C13	0.0170 (9)	0.0321 (11)	0.0246 (11)	0.0008 (8)	0.0044 (8)	−0.0013 (9)
C14	0.0297 (12)	0.0439 (13)	0.0284 (12)	−0.0028 (10)	0.0067 (9)	0.0052 (10)
N1	0.0226 (9)	0.0292 (9)	0.0243 (9)	−0.0015 (7)	0.0035 (7)	0.0008 (7)
O1	0.0311 (8)	0.0309 (8)	0.0283 (8)	−0.0012 (6)	0.0070 (6)	0.0028 (6)

Geometric parameters (Å, º) top

C1—O1	1.239 (2)	C7—N1	1.385 (2)
C1—C7	1.459 (3)	C8—N1	1.364 (2)
C1—C2	1.502 (3)	C8—C9	1.389 (3)
C2—C3	1.531 (3)	C8—C13	1.412 (3)
C2—H2A	0.9900	C9—C10	1.378 (3)
C2—H2B	0.9900	C9—H9	0.9500
C3—C4	1.524 (3)	C10—C11	1.420 (3)
C3—H3A	0.9900	C10—H10	0.9500
C3—H3B	0.9900	C11—C12	1.379 (3)
C4—C5	1.520 (3)	C11—C14	1.514 (3)
C4—H4A	0.9900	C12—C13	1.412 (3)
C4—H4B	0.9900	C12—H12	0.9500
C5—C6	1.494 (3)	C14—H14A	0.9800
C5—H5A	0.9900	C14—H14B	0.9800
C5—H5B	0.9900	C14—H14C	0.9800
C6—C7	1.393 (3)	N1—H1	0.8800
C6—C13	1.434 (3)

O1—C1—C7	118.77 (18)	N1—C7—C6	109.23 (17)
O1—C1—C2	118.56 (17)	N1—C7—C1	116.39 (17)
C7—C1—C2	122.64 (18)	C6—C7—C1	134.38 (18)
C1—C2—C3	118.96 (16)	N1—C8—C9	130.00 (18)
C1—C2—H2A	107.6	N1—C8—C13	107.80 (17)
C3—C2—H2A	107.6	C9—C8—C13	122.19 (18)
C1—C2—H2B	107.6	C10—C9—C8	117.27 (19)
C3—C2—H2B	107.6	C10—C9—H9	121.4
H2A—C2—H2B	107.0	C8—C9—H9	121.4
C4—C3—C2	114.21 (16)	C9—C10—C11	122.29 (19)
C4—C3—H3A	108.7	C9—C10—H10	118.9
C2—C3—H3A	108.7	C11—C10—H10	118.9
C4—C3—H3B	108.7	C12—C11—C10	119.84 (18)
C2—C3—H3B	108.7	C12—C11—C14	121.11 (18)
H3A—C3—H3B	107.6	C10—C11—C14	119.04 (18)
C5—C4—C3	113.79 (16)	C11—C12—C13	119.17 (18)
C5—C4—H4A	108.8	C11—C12—H12	120.4
C3—C4—H4A	108.8	C13—C12—H12	120.4
C5—C4—H4B	108.8	C12—C13—C8	119.21 (18)
C3—C4—H4B	108.8	C12—C13—C6	133.15 (18)
H4A—C4—H4B	107.7	C8—C13—C6	107.63 (16)
C6—C5—C4	116.99 (16)	C11—C14—H14A	109.5
C6—C5—H5A	108.1	C11—C14—H14B	109.5
C4—C5—H5A	108.1	H14A—C14—H14B	109.5
C6—C5—H5B	108.1	C11—C14—H14C	109.5
C4—C5—H5B	108.1	H14A—C14—H14C	109.5
H5A—C5—H5B	107.3	H14B—C14—H14C	109.5
C7—C6—C13	105.92 (16)	C8—N1—C7	109.40 (16)
C7—C6—C5	131.40 (17)	C8—N1—H1	125.3
C13—C6—C5	122.66 (17)	C7—N1—H1	125.3

O1—C1—C2—C3	165.37 (17)	C9—C10—C11—C12	0.0 (3)
C7—C1—C2—C3	−12.8 (3)	C9—C10—C11—C14	179.14 (17)
C1—C2—C3—C4	64.2 (2)	C10—C11—C12—C13	−1.0 (3)
C2—C3—C4—C5	−88.3 (2)	C14—C11—C12—C13	179.88 (17)
C3—C4—C5—C6	51.7 (2)	C11—C12—C13—C8	0.9 (3)
C4—C5—C6—C7	−9.5 (3)	C11—C12—C13—C6	−178.67 (19)
C4—C5—C6—C13	172.25 (17)	N1—C8—C13—C12	−178.80 (16)
C13—C6—C7—N1	0.32 (19)	C9—C8—C13—C12	0.3 (3)
C5—C6—C7—N1	−178.10 (18)	N1—C8—C13—C6	0.8 (2)
C13—C6—C7—C1	−179.5 (2)	C9—C8—C13—C6	179.93 (16)
C5—C6—C7—C1	2.0 (3)	C7—C6—C13—C12	178.9 (2)
O1—C1—C7—N1	−9.3 (3)	C5—C6—C13—C12	−2.5 (3)
C2—C1—C7—N1	168.83 (16)	C7—C6—C13—C8	−0.71 (19)
O1—C1—C7—C6	170.51 (19)	C5—C6—C13—C8	177.89 (16)
C2—C1—C7—C6	−11.3 (3)	C9—C8—N1—C7	−179.65 (18)
N1—C8—C9—C10	177.61 (18)	C13—C8—N1—C7	−0.7 (2)
C13—C8—C9—C10	−1.3 (3)	C6—C7—N1—C8	0.2 (2)
C8—C9—C10—C11	1.1 (3)	C1—C7—N1—C8	−179.91 (15)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.88	2.09	2.890 (2)	150
C4—H4a···O1ⁱⁱ	0.99	2.59	3.211 (3)	121
C2—H2B···Cg1ⁱⁱⁱ	0.99	2.88	3.740 (2)	146
C5—H5b···C10^iv	0.99	2.90	3.794 (2)	151

Symmetry codes: (i) −x, −y, −z+2; (ii) x, y+1, z; (iii) −x, −y+1, −z+2; (iv) −x+1/2, y+1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₁₄H₁₅NO
M_r	213.27
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	11.461 (3), 6.5062 (19), 14.459 (4)
β (°)	92.310 (4)
V (Å³)	1077.3 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.48 × 0.10 × 0.08

Data collection
Diffractometer	Bruker SMART APEX CCD diffractometer
Absorption correction	Multi-scan (SADABS as implemented in APEX2; Bruker, 2008)
T_min, T_max	0.731, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	9984, 2652, 1581
R_int	0.081
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.056, 0.135, 1.00
No. of reflections	2652
No. of parameters	146
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.19, −0.28

Computer programs: APEX2 (Bruker, 2008), SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006), 'SHELXTL (Sheldrick, 2008), Mercury (Macrae et al., 2006)'.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.88	2.09	2.890 (2)	149.9
C4—H4a···O1ⁱⁱ	0.99	2.59	3.211 (3)	121
C2—H2B···Cg1ⁱⁱⁱ	0.99	2.88	3.740 (2)	146
C5—H5b···C10^iv	0.99	2.90	3.794 (2)	151

Symmetry codes: (i) −x, −y, −z+2; (ii) x, y+1, z; (iii) −x, −y+1, −z+2; (iv) −x+1/2, y+1/2, −z+3/2.

Acknowledgements

We acknowledge UGC, New Delhi, India, for the award of Major Research Project grant No. F. 31–122/2005. MS thanks UGC, New Delhi, for the award of a research fellowship. The diffractometer was funded by NSF grant 0087210, by Ohio Board of Regents grant CAP-491, and by YSU.

References

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