2-Chloro-N-[(4-chloro­phen­yl)(phen­yl)meth­yl]-N-[2-(4-nitro-1H-imidazol-1-yl)eth­yl]ethanamine

Zhang, W.-T.; Zhou, C.-H.; Ji, Q.-G.

doi:10.1107/S160053681100256X

organic compounds

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ISSN: 2056-9890

Volume 67| Part 2| February 2011| Page o491

doi:10.1107/S160053681100256X

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2-Chloro-N-[(4-chlorophenyl)(phenyl)methyl]-N-[2-(4-nitro-1H-imidazol-1-yl)ethyl]ethanamine

Wen-Tai Zhang,^a Cheng-He Zhou ^a ^* and Qing-Gang Ji ^a

^aLaboratory of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China
^*Correspondence e-mail: zhouch@swu.edu.cn

(Received 18 January 2011; accepted 19 January 2011; online 26 January 2011)

In the title compound, C₂₀H₂₀Cl₂N₄O₂, the nitroimidazole ring makes dihedral angles of 17.00 (1) and 60.45 (11)° with the phenyl and chlorophenyl rings, respectively. The three-coordinate N atom connected to two methylene and one methine C atoms shows pyramidal coordination.

Related literature

For the use of nitrogen mustards containing the β-chloroethylamine unit as antitumor drugs, see: Zhuang et al. (2008 ). Nitroimidazole compounds are also used extensively in the treatment of various cancers as clinical radiosensitizers, see: Cai et al. (2009 ). For the synthesis, see: Fang et al. (2010 ); Gan et al. (2010 ).

Experimental

Crystal data

C₂₀H₂₀Cl₂N₄O₂
M_r = 419.30
Monoclinic, P 2₁ /n
a = 8.8206 (16) Å
b = 25.005 (5) Å
c = 9.0450 (17) Å
β = 100.802 (3)°
V = 1959.6 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.36 mm⁻¹
T = 298 K
0.32 × 0.24 × 0.18 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.903, T_max = 0.938
9838 measured reflections
3449 independent reflections
2464 reflections with I > 2σ(I)
R_int = 0.037

Refinement

R[F² > 2σ(F²)] = 0.053
wR(F²) = 0.139
S = 1.03
3449 reflections
253 parameters
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: SMART (Bruker, 2000 ); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681100256X/ng5107sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681100256X/ng5107Isup2.hkl

checkCIF report

Comment top

Nitrogen mustards as anticancer agents containing typical β-chloroethylamine moiety with easy synthesis and inexpensive expense are one of the most important antitumor drugs (Zhuang et al., 2008). Nitroimidazole compounds are also extensively used in the treatment of various cancers as clinical radiosensitizer (Cai et al., 2009). In view of this, it is of great interest for us to investigate the nitrogen mustard-based nitroimidazoles as new potential anticancer agents. Herein we would like to report the crystal structure of the title compound (I).

The title compound, C₂₀H₂₀Cl₂N₄O₂, crystallized in non-chiral monoclinic crystal system of P2(1)/n space group, including a racemic chiral isomers. In the molecule, the nitroimidazole ring makes dihedral angles of 17.00 (1) and 60.45 (11)°, respectively, with the benzene and chlorophenyl ring.

Related literature top

For the use of nitrogen mustards containing a β-chloroethylamine moiety as antitumor drugs, see: Zhuang et al. (2008). Nitroimidazole compounds are also used extensively in the treatment of various cancers as clinical radiosensitizers, see: Cai et al. (2009). For the synthesis, see: Fang et al. (2010); Gan et al. (2010).

Experimental top

The intermediate 2-chloro-N-(2-chloroethyl)-N-((4-chlorophenyl(phenyl)methyl)ethanamine (0.85 g, 2.5 mmol), which was prepared according to the procedure of Fang et al.(2010) and Gan et al.(2010), reacted with 4-nitroimidazole (0.34 g, 3.0 mmol) in the presence of weak base in acetonitrile at 60 °C for 12 h to produce the title compound (I) 0.30 g as white solid via silica gel column chromatography (ethyl acetate/petroleum ether, 1/2, V/V). A crystal of (I) suitable for X-ray analysis was grown from a mixture solution of ethyl acetate and petroleum ether by slow evaporation at room temperature.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. Ellipsoid plot.

2-Chloro-N-[(4-chlorophenyl)(phenyl)methyl]-N-[2-(4-nitro- 1H-imidazol-1-yl)ethyl]ethanamine top

Crystal data top

C₂₀H₂₀Cl₂N₄O₂	Z = 4
M_r = 419.30	F(000) = 872
Monoclinic, P2₁/n	D_x = 1.421 Mg m⁻³
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 8.8206 (16) Å	θ = 2.4–21.3°
b = 25.005 (5) Å	µ = 0.36 mm⁻¹
c = 9.0450 (17) Å	T = 298 K
β = 100.802 (3)°	Block, colourless
V = 1959.6 (6) Å³	0.32 × 0.24 × 0.18 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	3449 independent reflections
Radiation source: fine-focus sealed tube	2464 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.037
phi and ω scans	θ_max = 25.0°, θ_min = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→7
T_min = 0.903, T_max = 0.938	k = −29→29
9838 measured reflections	l = −10→10

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)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.139	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0576P)² + 0.904P] where P = (F_o² + 2F_c²)/3
3449 reflections	(Δ/σ)_max = 0.001
253 parameters	Δρ_max = 0.49 e Å⁻³
0 restraints	Δρ_min = −0.24 e Å⁻³

Crystal data top

C₂₀H₂₀Cl₂N₄O₂	V = 1959.6 (6) Å³
M_r = 419.30	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.8206 (16) Å	µ = 0.36 mm⁻¹
b = 25.005 (5) Å	T = 298 K
c = 9.0450 (17) Å	0.32 × 0.24 × 0.18 mm
β = 100.802 (3)°

Data collection top

Bruker SMART CCD area-detector diffractometer	3449 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2464 reflections with I > 2σ(I)
T_min = 0.903, T_max = 0.938	R_int = 0.037
9838 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.053	0 restraints
wR(F²) = 0.139	H-atom parameters constrained
S = 1.03	Δρ_max = 0.49 e Å⁻³
3449 reflections	Δρ_min = −0.24 e Å⁻³
253 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	0.3270 (3)	0.05952 (13)	0.0927 (3)	0.0487 (7)
C2	0.4173 (4)	0.01834 (13)	0.1569 (4)	0.0615 (9)
H2	0.3972	−0.0165	0.1231	0.074*
C3	0.5385 (4)	0.02915 (12)	0.2723 (3)	0.0538 (8)
H3	0.5994	0.0009	0.3161	0.065*
C4	0.5734 (3)	0.07989 (11)	0.3257 (3)	0.0402 (6)
C5	0.4771 (3)	0.12070 (12)	0.2588 (3)	0.0498 (7)
H5	0.4957	0.1556	0.2933	0.060*
C6	0.3544 (3)	0.11081 (12)	0.1423 (3)	0.0514 (8)
H6	0.2917	0.1386	0.0985	0.062*
C7	0.7143 (3)	0.08861 (11)	0.4496 (3)	0.0401 (6)
H7	0.7628	0.0533	0.4654	0.048*
C8	0.6827 (3)	0.10452 (10)	0.6032 (3)	0.0400 (6)
C9	0.8038 (3)	0.10174 (11)	0.7245 (3)	0.0456 (7)
H9	0.8999	0.0902	0.7091	0.055*
C10	0.7859 (4)	0.11550 (12)	0.8666 (3)	0.0536 (8)
H10	0.8695	0.1137	0.9463	0.064*
C11	0.6439 (4)	0.13203 (13)	0.8913 (4)	0.0592 (8)
H11	0.6313	0.1417	0.9875	0.071*
C12	0.5226 (4)	0.13412 (14)	0.7746 (4)	0.0657 (9)
H12	0.4263	0.1448	0.7912	0.079*
C13	0.5415 (3)	0.12044 (12)	0.6309 (3)	0.0538 (8)
H13	0.4573	0.1220	0.5518	0.065*
C14	0.9049 (3)	0.10277 (13)	0.2887 (3)	0.0547 (8)
H14A	0.9671	0.1308	0.2559	0.066*
H14B	0.8231	0.0941	0.2046	0.066*
C15	1.0037 (4)	0.05433 (13)	0.3272 (4)	0.0591 (8)
H15A	1.0457	0.0436	0.2400	0.071*
H15B	0.9407	0.0252	0.3526	0.071*
C16	0.7954 (3)	0.18032 (11)	0.3913 (3)	0.0498 (7)
H16A	0.7132	0.1884	0.4456	0.060*
H16B	0.7574	0.1876	0.2855	0.060*
C17	0.9333 (4)	0.21643 (13)	0.4485 (3)	0.0557 (8)
H17A	1.0205	0.2049	0.4051	0.067*
H17B	0.9081	0.2528	0.4158	0.067*
C18	1.1030 (3)	0.19238 (12)	0.6938 (4)	0.0523 (8)
H18	1.1775	0.1748	0.6516	0.063*
C19	0.9802 (3)	0.22472 (11)	0.8478 (3)	0.0479 (7)
C20	0.8953 (3)	0.23602 (11)	0.7104 (4)	0.0521 (8)
H20	0.8017	0.2542	0.6891	0.063*
Cl1	0.17478 (11)	0.04618 (4)	−0.05458 (11)	0.0835 (3)
Cl2	1.15787 (10)	0.06636 (4)	0.48090 (12)	0.0777 (3)
N1	0.8356 (2)	0.12352 (9)	0.4102 (2)	0.0412 (5)
N2	0.9760 (3)	0.21524 (9)	0.6115 (3)	0.0458 (6)
N3	1.1106 (3)	0.19743 (10)	0.8388 (3)	0.0538 (6)
N4	0.9403 (4)	0.23746 (13)	0.9901 (4)	0.0692 (8)
O1	1.0250 (3)	0.22177 (12)	1.1050 (3)	0.0897 (9)
O2	0.8228 (4)	0.26290 (15)	0.9864 (4)	0.1142 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0397 (16)	0.0603 (19)	0.0430 (17)	−0.0055 (14)	−0.0002 (13)	−0.0095 (14)
C2	0.059 (2)	0.0473 (18)	0.073 (2)	−0.0065 (16)	−0.0015 (18)	−0.0138 (16)
C3	0.0534 (18)	0.0446 (17)	0.060 (2)	0.0017 (14)	0.0013 (16)	−0.0014 (14)
C4	0.0360 (14)	0.0425 (15)	0.0416 (16)	0.0020 (12)	0.0059 (12)	0.0013 (12)
C5	0.0451 (16)	0.0416 (16)	0.0565 (19)	0.0023 (13)	−0.0061 (14)	−0.0055 (14)
C6	0.0427 (17)	0.0503 (18)	0.0561 (19)	0.0063 (14)	−0.0040 (14)	0.0038 (14)
C7	0.0361 (14)	0.0399 (15)	0.0417 (16)	0.0039 (12)	0.0005 (12)	0.0038 (12)
C8	0.0383 (15)	0.0369 (14)	0.0433 (16)	−0.0022 (12)	0.0041 (12)	0.0054 (12)
C9	0.0347 (15)	0.0561 (18)	0.0450 (17)	0.0012 (13)	0.0049 (13)	0.0102 (14)
C10	0.0498 (18)	0.068 (2)	0.0392 (17)	−0.0077 (16)	−0.0004 (14)	0.0072 (15)
C11	0.063 (2)	0.068 (2)	0.0475 (18)	−0.0007 (17)	0.0118 (16)	−0.0073 (16)
C12	0.0505 (19)	0.087 (3)	0.059 (2)	0.0159 (18)	0.0107 (17)	−0.0067 (18)
C13	0.0397 (16)	0.069 (2)	0.0493 (18)	0.0076 (15)	−0.0010 (14)	−0.0013 (15)
C14	0.0442 (17)	0.076 (2)	0.0419 (17)	−0.0036 (16)	0.0032 (14)	0.0063 (15)
C15	0.0513 (19)	0.072 (2)	0.057 (2)	−0.0036 (17)	0.0181 (16)	−0.0093 (17)
C16	0.0454 (17)	0.0521 (18)	0.0463 (17)	−0.0048 (14)	−0.0055 (14)	0.0111 (14)
C17	0.0549 (19)	0.0574 (19)	0.0500 (18)	−0.0139 (15)	−0.0022 (15)	0.0171 (15)
C18	0.0396 (16)	0.0621 (19)	0.054 (2)	0.0032 (15)	0.0060 (14)	0.0025 (15)
C19	0.0413 (16)	0.0467 (17)	0.0552 (19)	−0.0076 (14)	0.0074 (14)	−0.0049 (14)
C20	0.0404 (17)	0.0441 (17)	0.067 (2)	0.0010 (14)	−0.0030 (16)	−0.0054 (15)
Cl1	0.0626 (6)	0.0995 (7)	0.0751 (6)	−0.0043 (5)	−0.0216 (5)	−0.0236 (5)
Cl2	0.0537 (5)	0.0773 (6)	0.0937 (7)	0.0113 (4)	−0.0080 (5)	0.0054 (5)
N1	0.0341 (12)	0.0473 (13)	0.0411 (13)	0.0014 (10)	0.0038 (10)	0.0070 (10)
N2	0.0381 (13)	0.0465 (13)	0.0494 (15)	−0.0064 (11)	−0.0001 (11)	0.0047 (11)
N3	0.0452 (15)	0.0627 (16)	0.0507 (16)	−0.0013 (13)	0.0017 (12)	0.0051 (13)
N4	0.0560 (19)	0.080 (2)	0.072 (2)	−0.0215 (16)	0.0145 (17)	−0.0256 (17)
O1	0.094 (2)	0.117 (2)	0.0570 (16)	−0.0273 (18)	0.0125 (16)	−0.0085 (15)
O2	0.078 (2)	0.151 (3)	0.117 (3)	0.012 (2)	0.0262 (18)	−0.065 (2)

Geometric parameters (Å, º) top

C1—C2	1.364 (4)	C13—H13	0.9300
C1—C6	1.365 (4)	C14—N1	1.450 (4)
C1—Cl1	1.737 (3)	C14—C15	1.495 (4)
C2—C3	1.374 (4)	C14—H14A	0.9700
C2—H2	0.9300	C14—H14B	0.9700
C3—C4	1.372 (4)	C15—Cl2	1.779 (3)
C3—H3	0.9300	C15—H15A	0.9700
C4—C5	1.392 (4)	C15—H15B	0.9700
C4—C7	1.524 (4)	C16—N1	1.466 (3)
C5—C6	1.384 (4)	C16—C17	1.525 (4)
C5—H5	0.9300	C16—H16A	0.9700
C6—H6	0.9300	C16—H16B	0.9700
C7—N1	1.475 (3)	C17—N2	1.452 (4)
C7—C8	1.520 (4)	C17—H17A	0.9700
C7—H7	0.9800	C17—H17B	0.9700
C8—C13	1.375 (4)	C18—N3	1.307 (4)
C8—C9	1.382 (4)	C18—N2	1.350 (4)
C9—C10	1.368 (4)	C18—H18	0.9300
C9—H9	0.9300	C19—N3	1.353 (4)
C10—C11	1.376 (4)	C19—C20	1.355 (4)
C10—H10	0.9300	C19—N4	1.432 (4)
C11—C12	1.356 (4)	C20—N2	1.348 (4)
C11—H11	0.9300	C20—H20	0.9300
C12—C13	1.384 (4)	N4—O2	1.211 (4)
C12—H12	0.9300	N4—O1	1.225 (4)

C2—C1—C6	121.1 (3)	N1—C14—H14A	108.5
C2—C1—Cl1	119.2 (2)	C15—C14—H14A	108.5
C6—C1—Cl1	119.8 (2)	N1—C14—H14B	108.5
C1—C2—C3	119.0 (3)	C15—C14—H14B	108.5
C1—C2—H2	120.5	H14A—C14—H14B	107.5
C3—C2—H2	120.5	C14—C15—Cl2	111.8 (2)
C4—C3—C2	122.8 (3)	C14—C15—H15A	109.2
C4—C3—H3	118.6	Cl2—C15—H15A	109.2
C2—C3—H3	118.6	C14—C15—H15B	109.2
C3—C4—C5	116.5 (3)	Cl2—C15—H15B	109.2
C3—C4—C7	119.3 (2)	H15A—C15—H15B	107.9
C5—C4—C7	124.2 (2)	N1—C16—C17	112.0 (2)
C6—C5—C4	121.8 (3)	N1—C16—H16A	109.2
C6—C5—H5	119.1	C17—C16—H16A	109.2
C4—C5—H5	119.1	N1—C16—H16B	109.2
C1—C6—C5	118.9 (3)	C17—C16—H16B	109.2
C1—C6—H6	120.6	H16A—C16—H16B	107.9
C5—C6—H6	120.6	N2—C17—C16	111.8 (2)
N1—C7—C8	109.3 (2)	N2—C17—H17A	109.3
N1—C7—C4	115.8 (2)	C16—C17—H17A	109.3
C8—C7—C4	116.5 (2)	N2—C17—H17B	109.3
N1—C7—H7	104.6	C16—C17—H17B	109.3
C8—C7—H7	104.6	H17A—C17—H17B	107.9
C4—C7—H7	104.6	N3—C18—N2	113.2 (3)
C13—C8—C9	117.5 (3)	N3—C18—H18	123.4
C13—C8—C7	124.7 (3)	N2—C18—H18	123.4
C9—C8—C7	117.8 (2)	N3—C19—C20	112.3 (3)
C10—C9—C8	121.7 (3)	N3—C19—N4	121.4 (3)
C10—C9—H9	119.2	C20—C19—N4	126.2 (3)
C8—C9—H9	119.2	N2—C20—C19	105.0 (3)
C9—C10—C11	119.8 (3)	N2—C20—H20	127.5
C9—C10—H10	120.1	C19—C20—H20	127.5
C11—C10—H10	120.1	C14—N1—C16	112.7 (2)
C12—C11—C10	119.7 (3)	C14—N1—C7	113.5 (2)
C12—C11—H11	120.2	C16—N1—C7	115.5 (2)
C10—C11—H11	120.2	C20—N2—C18	106.5 (2)
C11—C12—C13	120.4 (3)	C20—N2—C17	126.7 (3)
C11—C12—H12	119.8	C18—N2—C17	126.8 (3)
C13—C12—H12	119.8	C18—N3—C19	103.0 (3)
C8—C13—C12	121.0 (3)	O2—N4—O1	125.0 (3)
C8—C13—H13	119.5	O2—N4—C19	116.4 (3)
C12—C13—H13	119.5	O1—N4—C19	118.5 (3)
N1—C14—C15	115.1 (2)

C6—C1—C2—C3	−0.6 (5)	N1—C14—C15—Cl2	−58.3 (3)
Cl1—C1—C2—C3	179.4 (2)	N1—C16—C17—N2	−70.4 (3)
C1—C2—C3—C4	−0.4 (5)	N3—C19—C20—N2	−0.3 (3)
C2—C3—C4—C5	1.3 (4)	N4—C19—C20—N2	−178.3 (3)
C2—C3—C4—C7	−177.3 (3)	C15—C14—N1—C16	156.5 (3)
C3—C4—C5—C6	−1.3 (4)	C15—C14—N1—C7	−69.7 (3)
C7—C4—C5—C6	177.2 (3)	C17—C16—N1—C14	−83.4 (3)
C2—C1—C6—C5	0.6 (5)	C17—C16—N1—C7	143.8 (2)
Cl1—C1—C6—C5	−179.4 (2)	C8—C7—N1—C14	163.5 (2)
C4—C5—C6—C1	0.4 (5)	C4—C7—N1—C14	−62.6 (3)
C3—C4—C7—N1	118.5 (3)	C8—C7—N1—C16	−64.1 (3)
C5—C4—C7—N1	−60.0 (3)	C4—C7—N1—C16	69.8 (3)
C3—C4—C7—C8	−110.9 (3)	C19—C20—N2—C18	0.6 (3)
C5—C4—C7—C8	70.6 (3)	C19—C20—N2—C17	179.6 (3)
N1—C7—C8—C13	121.7 (3)	N3—C18—N2—C20	−0.7 (3)
C4—C7—C8—C13	−11.9 (4)	N3—C18—N2—C17	−179.7 (3)
N1—C7—C8—C9	−59.8 (3)	C16—C17—N2—C20	−70.0 (4)
C4—C7—C8—C9	166.6 (2)	C16—C17—N2—C18	108.8 (3)
C13—C8—C9—C10	−1.6 (4)	N2—C18—N3—C19	0.4 (3)
C7—C8—C9—C10	179.7 (3)	C20—C19—N3—C18	−0.1 (3)
C8—C9—C10—C11	0.7 (4)	N4—C19—N3—C18	178.0 (3)
C9—C10—C11—C12	0.5 (5)	N3—C19—N4—O2	178.6 (3)
C10—C11—C12—C13	−0.9 (5)	C20—C19—N4—O2	−3.6 (5)
C9—C8—C13—C12	1.2 (4)	N3—C19—N4—O1	−2.0 (4)
C7—C8—C13—C12	179.8 (3)	C20—C19—N4—O1	175.8 (3)
C11—C12—C13—C8	0.0 (5)

Experimental details

Crystal data
Chemical formula	C₂₀H₂₀Cl₂N₄O₂
M_r	419.30
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	298
a, b, c (Å)	8.8206 (16), 25.005 (5), 9.0450 (17)
β (°)	100.802 (3)
V (Å³)	1959.6 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.36
Crystal size (mm)	0.32 × 0.24 × 0.18

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.903, 0.938
No. of measured, independent and observed [I > 2σ(I)] reflections	9838, 3449, 2464
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.053, 0.139, 1.03
No. of reflections	3449
No. of parameters	253
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.49, −0.24

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

We thank Southwest University (grant Nos. SWUB2006018 and XSGX0602), the Natural Science Foundation of Chongqing (grant No. 2009BB5296) and the Research Funds for the Central Universities (XDJK2009c092) for financial support.

References

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