2-Methyl-3-{2-nitro-1-[2-(prop-2-yn-1-yl­oxy)phen­yl]eth­yl}-1H-indole

Narayanan, P.; Sethusankar, K.; Ramachandiran, K.; Perumal, P.T.

doi:10.1107/S1600536811036907

organic compounds

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ISSN: 2056-9890

Volume 67| Part 10| October 2011| Page o2658

https://doi.org/10.1107/S1600536811036907

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2-Methyl-3-{2-nitro-1-[2-(prop-2-yn-1-yloxy)phenyl]ethyl}-1H-indole

P. Narayanan,^a K. Sethusankar,^a ^* K. Ramachandiran ^b and P. T. Perumal ^b

^aDepartment of Physics, RKM Vivekananda College (Autonomous), Chennai 600 004, India, and ^bOrganic Chemistry Division, Central Leather Research Institute, Adyar, Chennai 600 020, India
^*Correspondence e-mail: ksethusankar@yahoo.co.in

(Received 8 August 2011; accepted 12 September 2011; online 17 September 2011)

In the title compound, C₂₀H₁₈N₂O₃, the indole unit is essentially planar, with a maximum deviation of 0.0197 (18) Å for the N atom and forms a dihedral angle of 78.09 (9)° with the propyne-subsituted phenyl ring. The propyne group is almost linear, the C—C≡C angle being 176.5 (2)°, and is also in the flagpole position on the O atom. In the crystal, molecules are linked via N—H⋯O and C—H⋯O intermolecular hydrogen bonds involving the nitro-group O atoms as acceptors.

Related literature

For general backround to indoles, see: Gribble (1996 ); Mathiesen et al. (2005 ). For related structures, see: Narayanan et al. (2011 ); Ranjith et al. (2010 ). For bond-length distortions, see: Allen (1981 ).

Experimental

Crystal data

C₂₀H₁₈N₂O₃
M_r = 334.36
Tetragonal, I 4₁ /a
a = 23.3474 (7) Å
c = 12.8536 (7) Å
V = 7006.5 (5) Å³
Z = 16
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 295 K
0.30 × 0.25 × 0.20 mm

Data collection

Bruker Kappa APEXII diffractometer
31091 measured reflections
3954 independent reflections
2629 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.049
wR(F²) = 0.149
S = 1.03
3954 reflections
231 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O2ⁱ	0.86	2.14	2.997 (2)	173
C11—H11A⋯O1ⁱⁱ	0.97	2.52	3.433 (3)	157
C15—H15⋯O1ⁱⁱⁱ	0.93	2.57	3.315 (3)	137
Symmetry codes: (i) $[-y+{\script{3\over 4}}, x-{\script{1\over 4}}, -z+{\script{3\over 4}}]$ ; (ii) $[-y+{\script{5\over 4}}, x-{\script{1\over 4}}, z-{\script{1\over 4}}]$ ; (iii) $[y+{\script{1\over 4}}, -x+{\script{5\over 4}}, z-{\script{3\over 4}}]$ .

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; 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 Mercury (Macrae et al., 2008 ); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536811036907/rk2291sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811036907/rk2291Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536811036907/rk2291Isup3.cml

checkCIF report

Comment top

Indole is a common motif for drug target and as such, of new diversity–tolerant routes to this previleged biological scaffold continues to be of significant benefit (Gribble, 1996) and forms the basis of a wide variety of drugs, including the anti–inflammatory agent indomethacin, reserpine and sumatriptan. Indole derivatives are identified as interfering with a G protein–independent signalling pathway of the CRTH2 receptor (Mathiesen et al., 2005). As a part of our studies, we report herein the crystal structure of the title compound, which comprises the bicycle indole moiety, propyne subsituted phenyl ring and nitro methane group, as illustrated in (Fig. 1).

In the title compound, C₂₀H₁₈N₂O₃, the indole bicycle moiety (C1–C8/N1) is essentially planar with a maximum deviation of -0.0197 (18)Å for N1 atom. The indole moiety (C1–C8/N1) forms a dihedral angle of 78.09 (9)° with the propyne subsituted phenyl ring (C12–C17). In the indole ring system, the dihedral angle between the pyrrole ring (C5–C8/N1) and benzene ring (C1–C6) is 1.17 (10)°.

In the indole moiety, the endocyclic angles at C4 and C6 are contracted to 117.5 (2)° and 118.0 (17)°, respectively, while those at C2, C3 and C5 are expanded to 121.5 (2)°, 121.6 (3)° and 121.2 (3)°, respectively. This would appear to be a real effect caused by the fusion of the smaller pyrrole ring to the six–membered benzene ring, and the strain is taken up by the angular distortion rather than by bond–length distortions (Allen, 1981).

The angles around atom C10: [C7—C10—C12 = 113.88 (13)°, C7—C10—C11 = 110.41 (14)° and C12—C10—C11 = 109.95 (14)°] deviates significantly from ideal tetrahedral values which may be as a result of steric interactions between indole, nitromethane and propyne subsituted phenyl ring. The deviation of atom C10 from the indole moiety is -0.1066 (16)Å. The deviations of atom O3 from the phenyl ring (C12–C17) and propyne group (O3/C18/C19/C20) are 0.0504 (14)Å and 0.3088 (14)Å, respectively.

The oxygen subsituted propyne group is slightly twisted from the phenyl ring (C12–C17) which it is attached as evindenced by the torsion angle C16–C17–O3–C18 = 7.2 (3)°. The propyne group is almost linear, C18–C19≡C20 angle being 176.5 (2)°, and is also in the flagpole position on O3 atom. The title compound exhibits structural similarities with the already reported related structures (Narayanan et al., 2011; Ranjith et al., 2010).

In the crystal packing, molecules are linked via N—H···O and bifurcated C—H···O intermolecular hydrogen bonds involving the nitro group O atoms as acceptors (Table 1). The symmetry codes are: (i) -y+3/4, x-1/4, -z+3/4; (ii) -y+5/4, x-1/4, z-1/4; (iii) y+1/4, -x+5/4, z-3/4. The packing view of the title compound is shown in (Fig. 2).

Related literature top

For general backround to indoles, see: Gribble (1996); Mathiesen et al. (2005). For related structures, see: Narayanan et al. (2011); Ranjith et al. (2010). For bond-length distortions, see: Allen (1981).

Experimental top

To the nitroalkene (1.74 mmol) in water (10 ml) was added KHSO₄ (30 mol%) and the mixture was stirred for 5 minutes. 1–Ethyl–indole (1.74 mmol) was added to the mixture and the stirring was continued following the progress of the reaction by TLC. After completion of the reaction, the reaction mixture was extracted with ethyl acetate (3× 10 ml), dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure and the residue was column chromatographed over silica gel using EtOAc : Petroleum ether (1.5 : 8.5) as eluent to get the pure product.

Structure description top

For general backround to indoles, see: Gribble (1996); Mathiesen et al. (2005). For related structures, see: Narayanan et al. (2011); Ranjith et al. (2010). For bond-length distortions, see: Allen (1981).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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 Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at 30% probability level. H atoms are present as small spheres of arbitary radius.
	Fig. 2. The packing arrangement of the title compound viewed down a axis. Dashed lines indicates the N—H···O and bifurcated C—H···O intermolecular hydrogen bonds. Symmetry codes as in the Table 1.

2-Methyl-3-{2-nitro-1-[2-(prop-2-yn-1-yloxy)phenyl]ethyl}-1H-indole top

Crystal data top

C₂₀H₁₈N₂O₃	D_x = 1.268 Mg m⁻³
M_r = 334.36	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4₁/a	Cell parameters from 3954 reflections
Hall symbol: -I 4ad	θ = 2.5–27.3°
a = 23.3474 (7) Å	µ = 0.09 mm⁻¹
c = 12.8536 (7) Å	T = 295 K
V = 7006.5 (5) Å³	Block, brown
Z = 16	0.30 × 0.25 × 0.20 mm
F(000) = 2816

Data collection top

Bruker Kappa APEXII diffractometer	2629 reflections with I > 2σ(I)
Radiation source: fine–focus sealed tube	R_int = 0.034
Graphite monochromator	θ_max = 27.3°, θ_min = 2.5°
ω and φ scans	h = −30→30
31091 measured reflections	k = −30→30
3954 independent reflections	l = −16→16

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.149	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.061P)² + 4.4075P] where P = (F_o² + 2F_c²)/3
3954 reflections	(Δ/σ)_max = 0.001
231 parameters	Δρ_max = 0.35 e Å⁻³
0 restraints	Δρ_min = −0.30 e Å⁻³

Crystal data top

C₂₀H₁₈N₂O₃	Z = 16
M_r = 334.36	Mo Kα radiation
Tetragonal, I4₁/a	µ = 0.09 mm⁻¹
a = 23.3474 (7) Å	T = 295 K
c = 12.8536 (7) Å	0.30 × 0.25 × 0.20 mm
V = 7006.5 (5) Å³

Data collection top

Bruker Kappa APEXII diffractometer	2629 reflections with I > 2σ(I)
31091 measured reflections	R_int = 0.034
3954 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.149	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.35 e Å⁻³
3954 reflections	Δρ_min = −0.30 e Å⁻³
231 parameters

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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	0.57180 (8)	0.58359 (8)	0.28887 (15)	0.0561 (5)
H1	0.6050	0.5907	0.2511	0.067*
C2	0.54456 (11)	0.62723 (10)	0.34038 (18)	0.0739 (6)
H2	0.5595	0.6641	0.3365	0.089*
C3	0.49531 (12)	0.61764 (12)	0.39812 (19)	0.0837 (7)
H3	0.4784	0.6480	0.4335	0.100*
C4	0.47114 (10)	0.56413 (12)	0.40392 (16)	0.0746 (6)
H4	0.4379	0.5577	0.4421	0.090*
C5	0.49805 (8)	0.52014 (9)	0.35072 (14)	0.0567 (5)
C6	0.54906 (7)	0.52835 (8)	0.29372 (12)	0.0471 (4)
C7	0.56448 (7)	0.47343 (7)	0.25110 (12)	0.0456 (4)
C8	0.52332 (8)	0.43530 (9)	0.28289 (14)	0.0574 (5)
C9	0.51646 (12)	0.37274 (10)	0.2625 (2)	0.0854 (7)
H9A	0.4937	0.3559	0.3167	0.128*
H9B	0.5535	0.3548	0.2610	0.128*
H9C	0.4978	0.3673	0.1967	0.128*
C10	0.61764 (7)	0.45897 (7)	0.19019 (12)	0.0461 (4)
H10	0.6150	0.4185	0.1703	0.055*
C11	0.67081 (8)	0.46567 (9)	0.25835 (14)	0.0556 (5)
H11A	0.7049	0.4568	0.2182	0.067*
H11B	0.6738	0.5049	0.2826	0.067*
C12	0.62457 (7)	0.49375 (7)	0.09048 (12)	0.0466 (4)
C13	0.66337 (9)	0.53799 (9)	0.07902 (15)	0.0608 (5)
H13	0.6877	0.5469	0.1339	0.073*
C14	0.66695 (11)	0.56947 (10)	−0.01207 (17)	0.0747 (6)
H14	0.6936	0.5989	−0.0182	0.090*
C15	0.63101 (11)	0.55691 (10)	−0.09283 (17)	0.0741 (6)
H15	0.6327	0.5785	−0.1536	0.089*
C16	0.59234 (10)	0.51273 (9)	−0.08517 (14)	0.0627 (5)
H16	0.5681	0.5044	−0.1406	0.075*
C17	0.58959 (8)	0.48052 (8)	0.00541 (13)	0.0486 (4)
C18	0.52168 (9)	0.41607 (9)	−0.06941 (14)	0.0626 (5)
H18A	0.5476	0.4081	−0.1266	0.075*
H18B	0.4952	0.4458	−0.0912	0.075*
C19	0.49038 (9)	0.36474 (10)	−0.04196 (16)	0.0655 (5)
C20	0.46475 (12)	0.32315 (15)	−0.0253 (2)	0.0902 (8)
N1	0.48348 (7)	0.46368 (8)	0.34151 (12)	0.0659 (5)
H1A	0.4536	0.4482	0.3687	0.079*
N2	0.66652 (9)	0.42633 (9)	0.34832 (17)	0.0796 (6)
O1	0.66570 (12)	0.44706 (10)	0.43438 (16)	0.1362 (10)
O2	0.66138 (13)	0.37606 (8)	0.3327 (2)	0.1423 (10)
O3	0.55338 (6)	0.43482 (6)	0.01938 (9)	0.0586 (4)
H20	0.4442 (13)	0.2919 (12)	−0.011 (2)	0.118 (11)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0576 (11)	0.0581 (11)	0.0526 (10)	0.0033 (9)	−0.0041 (9)	0.0056 (9)
C2	0.0856 (16)	0.0634 (13)	0.0727 (14)	0.0126 (11)	−0.0077 (12)	0.0021 (11)
C3	0.0949 (18)	0.0863 (17)	0.0700 (15)	0.0366 (14)	−0.0004 (13)	−0.0033 (13)
C4	0.0628 (13)	0.1061 (19)	0.0551 (12)	0.0235 (13)	0.0091 (10)	0.0114 (12)
C5	0.0506 (10)	0.0771 (13)	0.0423 (9)	0.0048 (9)	−0.0010 (8)	0.0119 (9)
C6	0.0461 (9)	0.0606 (10)	0.0346 (8)	0.0030 (8)	−0.0055 (7)	0.0109 (7)
C7	0.0482 (9)	0.0536 (10)	0.0351 (8)	−0.0032 (7)	−0.0042 (7)	0.0098 (7)
C8	0.0602 (11)	0.0666 (12)	0.0453 (9)	−0.0122 (9)	−0.0003 (8)	0.0121 (9)
C9	0.1018 (18)	0.0704 (15)	0.0841 (16)	−0.0319 (13)	0.0091 (14)	0.0090 (12)
C10	0.0505 (9)	0.0473 (9)	0.0405 (8)	0.0002 (7)	−0.0030 (7)	0.0045 (7)
C11	0.0536 (10)	0.0630 (11)	0.0503 (10)	0.0055 (9)	−0.0033 (8)	0.0066 (9)
C12	0.0496 (9)	0.0515 (9)	0.0387 (8)	0.0034 (7)	0.0057 (7)	0.0033 (7)
C13	0.0667 (12)	0.0661 (12)	0.0497 (10)	−0.0107 (9)	0.0081 (9)	0.0049 (9)
C14	0.0923 (16)	0.0709 (14)	0.0610 (13)	−0.0162 (12)	0.0210 (12)	0.0106 (11)
C15	0.1057 (18)	0.0701 (13)	0.0466 (11)	0.0043 (12)	0.0202 (11)	0.0167 (10)
C16	0.0816 (14)	0.0664 (12)	0.0400 (10)	0.0116 (11)	0.0039 (9)	0.0073 (9)
C17	0.0527 (10)	0.0539 (10)	0.0392 (8)	0.0083 (8)	0.0044 (7)	0.0031 (7)
C18	0.0674 (12)	0.0758 (13)	0.0447 (10)	0.0065 (10)	−0.0129 (9)	−0.0074 (9)
C19	0.0575 (12)	0.0849 (15)	0.0542 (11)	0.0005 (11)	−0.0083 (9)	−0.0130 (11)
C20	0.0810 (17)	0.109 (2)	0.0808 (17)	−0.0283 (17)	−0.0087 (13)	−0.0050 (16)
N1	0.0560 (9)	0.0874 (12)	0.0542 (9)	−0.0139 (9)	0.0098 (8)	0.0156 (9)
N2	0.0929 (14)	0.0688 (12)	0.0771 (13)	−0.0006 (10)	−0.0388 (11)	0.0223 (10)
O1	0.211 (3)	0.1348 (18)	0.0629 (11)	−0.0503 (17)	−0.0414 (14)	0.0353 (12)
O2	0.209 (3)	0.0599 (11)	0.158 (2)	0.0096 (13)	−0.0778 (19)	0.0308 (12)
O3	0.0645 (8)	0.0686 (8)	0.0428 (7)	−0.0091 (6)	−0.0115 (6)	0.0054 (6)

Geometric parameters (Å, º) top

C1—C2	1.371 (3)	C11—H11A	0.9700
C1—C6	1.396 (3)	C11—H11B	0.9700
C1—H1	0.9300	C12—C13	1.382 (3)
C2—C3	1.387 (3)	C12—C17	1.399 (2)
C2—H2	0.9300	C13—C14	1.385 (3)
C3—C4	1.373 (4)	C13—H13	0.9300
C3—H3	0.9300	C14—C15	1.367 (3)
C4—C5	1.384 (3)	C14—H14	0.9300
C4—H4	0.9300	C15—C16	1.374 (3)
C5—N1	1.367 (3)	C15—H15	0.9300
C5—C6	1.411 (2)	C16—C17	1.387 (2)
C6—C7	1.440 (3)	C16—H16	0.9300
C7—C8	1.372 (2)	C17—O3	1.373 (2)
C7—C10	1.506 (2)	C18—O3	1.429 (2)
C8—N1	1.368 (3)	C18—C19	1.447 (3)
C8—C9	1.492 (3)	C18—H18A	0.9700
C9—H9A	0.9600	C18—H18B	0.9700
C9—H9B	0.9600	C19—C20	1.160 (4)
C9—H9C	0.9600	C20—H20	0.89 (3)
C10—C12	1.526 (2)	N1—H1A	0.8600
C10—C11	1.528 (2)	N2—O2	1.197 (3)
C10—H10	0.9800	N2—O1	1.208 (3)
C11—N2	1.480 (3)

C2—C1—C6	119.24 (19)	C10—C11—H11A	109.8
C2—C1—H1	120.4	N2—C11—H11B	109.8
C6—C1—H1	120.4	C10—C11—H11B	109.8
C1—C2—C3	121.5 (2)	H11A—C11—H11B	108.3
C1—C2—H2	119.2	C13—C12—C17	117.67 (16)
C3—C2—H2	119.2	C13—C12—C10	123.84 (16)
C4—C3—C2	121.1 (2)	C17—C12—C10	118.49 (15)
C4—C3—H3	119.4	C12—C13—C14	121.8 (2)
C2—C3—H3	119.4	C12—C13—H13	119.1
C3—C4—C5	117.5 (2)	C14—C13—H13	119.1
C3—C4—H4	121.3	C15—C14—C13	119.4 (2)
C5—C4—H4	121.3	C15—C14—H14	120.3
N1—C5—C4	130.19 (19)	C13—C14—H14	120.3
N1—C5—C6	107.22 (17)	C14—C15—C16	120.67 (19)
C4—C5—C6	122.6 (2)	C14—C15—H15	119.7
C1—C6—C5	118.00 (17)	C16—C15—H15	119.7
C1—C6—C7	135.28 (16)	C15—C16—C17	119.8 (2)
C5—C6—C7	106.71 (16)	C15—C16—H16	120.1
C8—C7—C6	106.82 (16)	C17—C16—H16	120.1
C8—C7—C10	125.92 (17)	O3—C17—C16	124.02 (17)
C6—C7—C10	127.11 (15)	O3—C17—C12	115.38 (14)
N1—C8—C7	109.02 (18)	C16—C17—C12	120.60 (18)
N1—C8—C9	119.85 (18)	O3—C18—C19	108.69 (16)
C7—C8—C9	131.1 (2)	O3—C18—H18A	110.0
C8—C9—H9A	109.5	C19—C18—H18A	110.0
C8—C9—H9B	109.5	O3—C18—H18B	110.0
H9A—C9—H9B	109.5	C19—C18—H18B	110.0
C8—C9—H9C	109.5	H18A—C18—H18B	108.3
H9A—C9—H9C	109.5	C20—C19—C18	176.5 (2)
H9B—C9—H9C	109.5	C19—C20—H20	178 (2)
C7—C10—C12	113.88 (13)	C5—N1—C8	110.22 (15)
C7—C10—C11	110.41 (14)	C5—N1—H1A	124.9
C12—C10—C11	109.95 (14)	C8—N1—H1A	124.9
C7—C10—H10	107.4	O2—N2—O1	123.0 (2)
C12—C10—H10	107.4	O2—N2—C11	119.0 (2)
C11—C10—H10	107.4	O1—N2—C11	117.9 (2)
N2—C11—C10	109.25 (15)	C17—O3—C18	116.90 (14)
N2—C11—H11A	109.8

C6—C1—C2—C3	0.7 (3)	C7—C10—C12—C13	105.5 (2)
C1—C2—C3—C4	−1.5 (4)	C11—C10—C12—C13	−19.0 (2)
C2—C3—C4—C5	0.5 (3)	C7—C10—C12—C17	−74.2 (2)
C3—C4—C5—N1	−179.0 (2)	C11—C10—C12—C17	161.27 (16)
C3—C4—C5—C6	1.3 (3)	C17—C12—C13—C14	1.7 (3)
C2—C1—C6—C5	1.0 (3)	C10—C12—C13—C14	−178.07 (18)
C2—C1—C6—C7	179.47 (19)	C12—C13—C14—C15	0.4 (3)
N1—C5—C6—C1	178.18 (15)	C13—C14—C15—C16	−1.3 (4)
C4—C5—C6—C1	−2.0 (3)	C14—C15—C16—C17	0.1 (3)
N1—C5—C6—C7	−0.71 (19)	C15—C16—C17—O3	−178.42 (18)
C4—C5—C6—C7	179.09 (17)	C15—C16—C17—C12	2.1 (3)
C1—C6—C7—C8	−178.48 (19)	C13—C12—C17—O3	177.55 (16)
C5—C6—C7—C8	0.12 (18)	C10—C12—C17—O3	−2.7 (2)
C1—C6—C7—C10	5.8 (3)	C13—C12—C17—C16	−2.9 (3)
C5—C6—C7—C10	−175.64 (15)	C10—C12—C17—C16	176.84 (16)
C6—C7—C8—N1	0.52 (19)	C4—C5—N1—C8	−178.7 (2)
C10—C7—C8—N1	176.34 (15)	C6—C5—N1—C8	1.1 (2)
C6—C7—C8—C9	179.6 (2)	C7—C8—N1—C5	−1.0 (2)
C10—C7—C8—C9	−4.6 (3)	C9—C8—N1—C5	179.79 (18)
C8—C7—C10—C12	125.70 (18)	C10—C11—N2—O2	58.0 (3)
C6—C7—C10—C12	−59.3 (2)	C10—C11—N2—O1	−118.6 (2)
C8—C7—C10—C11	−110.05 (19)	C16—C17—O3—C18	7.2 (3)
C6—C7—C10—C11	64.9 (2)	C12—C17—O3—C18	−173.23 (16)
C7—C10—C11—N2	60.3 (2)	C19—C18—O3—C17	174.73 (16)
C12—C10—C11—N2	−173.18 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2ⁱ	0.86	2.14	2.997 (2)	173
C11—H11A···O1ⁱⁱ	0.97	2.52	3.433 (3)	157
C15—H15···O1ⁱⁱⁱ	0.93	2.57	3.315 (3)	137

Symmetry codes: (i) −y+3/4, x−1/4, −z+3/4; (ii) −y+5/4, x−1/4, z−1/4; (iii) y+1/4, −x+5/4, z−3/4.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₈N₂O₃
M_r	334.36
Crystal system, space group	Tetragonal, I4₁/a
Temperature (K)	295
a, c (Å)	23.3474 (7), 12.8536 (7)
V (Å³)	7006.5 (5)
Z	16
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.30 × 0.25 × 0.20

Data collection
Diffractometer	Bruker Kappa APEXII
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	31091, 3954, 2629
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.646

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.149, 1.03
No. of reflections	3954
No. of parameters	231
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.30

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2ⁱ	0.86	2.14	2.997 (2)	172.6
C11—H11A···O1ⁱⁱ	0.97	2.52	3.433 (3)	156.5
C15—H15···O1ⁱⁱⁱ	0.93	2.57	3.315 (3)	137.2

Symmetry codes: (i) −y+3/4, x−1/4, −z+3/4; (ii) −y+5/4, x−1/4, z−1/4; (iii) y+1/4, −x+5/4, z−3/4.

Acknowledgements

PN and KS thank Dr Babu Varghese, SAIF, IIT, Chennai, India, for the X–ray intensity data collection and Dr V. Murugan, Head of the Department of Physics, for providing facilities in the department to carry out this work.

References

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