2-tert-Butyl-6-[(4-chloro-2-nitro­phen­yl)diazen­yl]-4-methylphenol

Wen, H.-L.; Wu, X.-Q.; Lai, B.-W.

doi:10.1107/S1600536809019631

organic compounds

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ISSN: 2056-9890

Volume 65| Part 7| July 2009| Page o1520

doi:10.1107/S1600536809019631

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2-tert-Butyl-6-[(4-chloro-2-nitrophenyl)diazenyl]-4-methylphenol

Hui-Liang Wen,^a ^* Xiao-Qin Wu ^a and Bo-Wen Lai ^b

^aState Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, People's Republic of China, and ^bDepartment of Chemistry, Nanchang University, Nanchang 330047, People's Republic of China
^*Correspondence e-mail: hlwen70@163.com

(Received 9 May 2009; accepted 23 May 2009; online 6 June 2009)

In the title compound, C₁₇H₁₈ClN₃O₃, the dihedral angle between the planes of the two benzene rings is 1.03 (7)°. The overall conformation of the molecule is influenced, in part, by electron delocalization and by an intramolecular bifurcated O—H⋯(O,N) hydrogen bonds. The O atoms of the nitro group, one of which serves as an H bond acceptor, are disordered over two sets of sites with refined occupancies of 0.56 (3) and 0.44 (3).

Related literature

For benzotriazoles as UV absorbers and their applications in industry, see: Ravichandran et al. (2002 ). N-oxides are a key type intermediates in the synthesis of benzotriazoles, see: Wen et al. (2006 ); Crawford (1999 ). For the use of green synthetic methods to obtain intermediates, see: Tanaka & Toda (2000 ).

Experimental

Crystal data

C₁₇H₁₈ClN₃O₃
M_r = 347.79
Monoclinic, P 2₁ /c
a = 14.578 (4) Å
b = 7.0616 (19) Å
c = 17.043 (5) Å
β = 101.233 (3)°
V = 1720.9 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 296 K
0.31 × 0.18 × 0.16 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.930, T_max = 0.963
14642 measured reflections
3927 independent reflections
2563 reflections with I > 2σ(I)
R_int = 0.033

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.141
S = 1.03
3927 reflections
241 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O1′	0.82	2.28	2.933 (7)	136
O3—H3⋯O1	0.82	2.50	3.142 (12)	136
O3—H3⋯N2	0.82	1.84	2.553 (2)	145

Data collection: APEX2 (Bruker, 2006 ); cell refinement: SAINT (Bruker, 2006); 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 global, I. DOI: 10.1107/S1600536809019631/lh2824sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809019631/lh2824Isup2.hkl

checkCIF report

Comment top

Benzotriazoles play an important role as a class of UV absorbers and have promising industrial applications (Ravichandran et al., 2002). N-oxides are a key type intermediates in the synthesis of benzotriazoles (Wen et al., 2006; Crawford, 1999) and the title compound is an important intermediate in the synthesis of 2-(2'-Hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chloro benzotriazole (UV 326), a good ultraviolet absorber. Due to the growing awareness of environmental protection, the demand for clean and 'green' (i.e solvent free) chemical syntheses has been growing, so using these synthetic methods to form intermediates have received attention (Tanaka & Toda, 2000). Herein we report a 'green' synthetic method and the crystal structure of the title compound. In the title moleclue (Fig .1) the dihedral angle between the two benzene rings is 1.03 (7)°. The overall conformation of the molecule is influenced, in part, by electron delocalization and by intramolecular O—H···O and O—H···N hydrogen bonds.

Related literature top

For benzotriazoles as UV absorbers and their applications in industry, see: Ravichandran et al. (2002). N-oxides are a key type intermediates in the synthesis of benzotriazoles, see: Wen et al. (2006); Crawford (1999). For the use of green synthetic methods to obtain intermediates, see: Tanaka & Toda (2000).

Experimental top

The title compound was synthesized via the solid phase reaction of 4-chloro-2-nitroaniline and 2-tert-butyl-4-substituted phenol at room temperature. After intensive grinding a mixture of 4-chloro-2-nitrobenzenamine 1.72 g (10 mmol), 2-tert-butyl-4-methylphenol 1.72 g (10.5 mmol), NaNO₂ 0.69 g (10 mmol), and KHSO₄ 1.36 g (10 mmol) in a mortar for 15 min at 293 K, the product was washed with hot water. A few purple crystals suitable for X-ray diffraction analysis were obtained upon recrystallization in ethanol after several days (m. p. 445–446 K), which gave the product in 93% yield and higher than 99% purity (by HPLC).

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); 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. : The molecular structure of the title compound, showing 30% probability displacement ellipsoids. The minor comonent of disorder is shown with open bonds and hydrogen bonds are shown with dashed lines.

2-tert-Butyl-6-[(4-chloro-2-nitrophenyl)diazenyl]-4-methylphenol top

Crystal data top

C₁₇H₁₈ClN₃O₃	F(000) = 728
M_r = 347.79	D_x = 1.342 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4044 reflections
a = 14.578 (4) Å	θ = 2.6–27.2°
b = 7.0616 (19) Å	µ = 0.24 mm⁻¹
c = 17.043 (5) Å	T = 296 K
β = 101.233 (3)°	Block, purple
V = 1720.9 (8) Å³	0.31 × 0.18 × 0.16 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	3927 independent reflections
Radiation source: fine-focus sealed tube	2563 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.033
ϕ and ω scans	θ_max = 27.5°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −18→18
T_min = 0.930, T_max = 0.963	k = −9→8
14642 measured reflections	l = −22→22

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.141	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0591P)² + 0.5672P] where P = (F_o² + 2F_c²)/3
3927 reflections	(Δ/σ)_max = 0.002
241 parameters	Δρ_max = 0.22 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

Crystal data top

C₁₇H₁₈ClN₃O₃	V = 1720.9 (8) Å³
M_r = 347.79	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 14.578 (4) Å	µ = 0.24 mm⁻¹
b = 7.0616 (19) Å	T = 296 K
c = 17.043 (5) Å	0.31 × 0.18 × 0.16 mm
β = 101.233 (3)°

Data collection top

Bruker APEXII CCD diffractometer	3927 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2563 reflections with I > 2σ(I)
T_min = 0.930, T_max = 0.963	R_int = 0.033
14642 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.141	H-atom parameters constrained
S = 1.03	Δρ_max = 0.22 e Å⁻³
3927 reflections	Δρ_min = −0.26 e Å⁻³
241 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	Occ. (<1)
Cl1	1.37753 (4)	0.52156 (11)	0.44085 (5)	0.0871 (3)
O1	0.9625 (4)	0.559 (3)	0.2905 (6)	0.109 (4)	0.56 (3)
O2	1.0758 (7)	0.659 (2)	0.2334 (6)	0.115 (4)	0.56 (3)
O3	0.81516 (9)	0.7932 (3)	0.36241 (8)	0.0666 (5)
H3	0.8703	0.7643	0.3663	0.100*
O1'	0.9670 (8)	0.689 (4)	0.2804 (4)	0.100 (5)	0.44 (3)
O2'	1.0687 (12)	0.545 (5)	0.2372 (10)	0.156 (8)	0.44 (3)
N1	1.04252 (15)	0.6167 (4)	0.29115 (12)	0.0765 (6)
N2	0.98233 (10)	0.7293 (2)	0.43581 (9)	0.0475 (4)
N3	0.96277 (10)	0.7767 (2)	0.50347 (9)	0.0468 (4)
C1	1.10633 (13)	0.6202 (3)	0.36932 (12)	0.0528 (5)
C2	1.19824 (14)	0.5718 (3)	0.36947 (14)	0.0597 (5)
H2	1.2171	0.5395	0.3221	0.072*
C3	1.26084 (14)	0.5723 (3)	0.44035 (15)	0.0599 (6)
C4	1.23301 (14)	0.6162 (3)	0.51114 (14)	0.0606 (5)
H4	1.2760	0.6122	0.5592	0.073*
C5	1.14154 (13)	0.6660 (3)	0.51035 (12)	0.0537 (5)
H5	1.1233	0.6963	0.5582	0.064*
C6	1.07582 (12)	0.6716 (3)	0.43917 (11)	0.0468 (4)
C7	0.87202 (12)	0.8321 (3)	0.50305 (10)	0.0425 (4)
C8	0.85301 (13)	0.8758 (3)	0.57888 (11)	0.0465 (4)
H8	0.9010	0.8707	0.6236	0.056*
C9	0.76528 (13)	0.9255 (3)	0.58763 (10)	0.0473 (4)
C10	0.69528 (13)	0.9379 (3)	0.51815 (11)	0.0485 (5)
H10	0.6358	0.9748	0.5242	0.058*
C11	0.70815 (12)	0.8993 (3)	0.44168 (10)	0.0485 (5)
C12	0.79931 (12)	0.8412 (3)	0.43353 (10)	0.0465 (4)
C13	0.74126 (16)	0.9610 (4)	0.66868 (11)	0.0646 (6)
H13A	0.7066	0.8553	0.6831	0.097*
H13B	0.7042	1.0738	0.6666	0.097*
H13C	0.7978	0.9763	0.7078	0.097*
C14	0.62867 (14)	0.9137 (4)	0.36802 (12)	0.0658 (6)
C15	0.53856 (16)	0.9904 (5)	0.39088 (14)	0.0868 (9)
H15A	0.5192	0.9069	0.4290	0.130*
H15B	0.4901	0.9979	0.3439	0.130*
H15C	0.5502	1.1142	0.4139	0.130*
C16	0.65620 (18)	1.0504 (5)	0.30642 (14)	0.0959 (10)
H16A	0.6645	1.1753	0.3290	0.144*
H16B	0.6077	1.0528	0.2594	0.144*
H16C	0.7136	1.0087	0.2924	0.144*
C17	0.60711 (17)	0.7157 (5)	0.33203 (15)	0.0931 (10)
H17A	0.6629	0.6623	0.3190	0.140*
H17B	0.5598	0.7250	0.2844	0.140*
H17C	0.5852	0.6360	0.3701	0.140*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0412 (3)	0.1022 (5)	0.1217 (6)	0.0083 (3)	0.0251 (3)	0.0142 (4)
O1	0.052 (2)	0.186 (11)	0.084 (3)	−0.001 (4)	−0.001 (2)	−0.047 (5)
O2	0.105 (4)	0.185 (9)	0.056 (3)	−0.001 (5)	0.016 (3)	0.012 (4)
O3	0.0420 (7)	0.1165 (13)	0.0417 (7)	0.0091 (8)	0.0094 (6)	−0.0118 (8)
O1'	0.070 (4)	0.173 (13)	0.055 (3)	0.043 (5)	0.007 (2)	−0.013 (4)
O2'	0.115 (7)	0.255 (18)	0.091 (7)	0.062 (10)	0.007 (5)	−0.080 (9)
N1	0.0612 (13)	0.1073 (17)	0.0606 (12)	0.0158 (13)	0.0106 (10)	−0.0208 (12)
N2	0.0388 (8)	0.0553 (10)	0.0491 (9)	−0.0003 (7)	0.0102 (7)	−0.0025 (7)
N3	0.0412 (8)	0.0512 (9)	0.0478 (9)	−0.0017 (7)	0.0083 (7)	−0.0007 (7)
C1	0.0465 (11)	0.0550 (12)	0.0571 (12)	0.0003 (9)	0.0106 (9)	−0.0026 (9)
C2	0.0503 (12)	0.0634 (14)	0.0702 (14)	0.0041 (10)	0.0232 (11)	0.0006 (11)
C3	0.0385 (10)	0.0570 (13)	0.0869 (16)	0.0007 (9)	0.0186 (11)	0.0079 (11)
C4	0.0429 (11)	0.0655 (13)	0.0699 (14)	−0.0021 (9)	0.0021 (10)	0.0061 (11)
C5	0.0455 (11)	0.0588 (12)	0.0561 (12)	−0.0017 (9)	0.0084 (9)	0.0023 (9)
C6	0.0394 (9)	0.0460 (10)	0.0554 (11)	−0.0029 (8)	0.0104 (8)	−0.0006 (8)
C7	0.0374 (9)	0.0472 (10)	0.0425 (9)	−0.0019 (7)	0.0072 (7)	−0.0006 (8)
C8	0.0469 (10)	0.0531 (11)	0.0378 (9)	−0.0022 (8)	0.0038 (8)	0.0008 (8)
C9	0.0515 (11)	0.0542 (11)	0.0380 (9)	−0.0012 (9)	0.0131 (8)	0.0004 (8)
C10	0.0418 (10)	0.0617 (12)	0.0441 (10)	0.0039 (8)	0.0139 (8)	0.0015 (9)
C11	0.0402 (10)	0.0668 (13)	0.0384 (9)	−0.0008 (9)	0.0074 (7)	0.0002 (9)
C12	0.0418 (10)	0.0606 (12)	0.0381 (9)	0.0003 (8)	0.0102 (8)	−0.0032 (8)
C13	0.0651 (13)	0.0909 (17)	0.0408 (10)	0.0048 (12)	0.0178 (10)	−0.0003 (11)
C14	0.0399 (11)	0.115 (2)	0.0415 (10)	0.0116 (11)	0.0065 (8)	−0.0021 (11)
C15	0.0470 (12)	0.156 (3)	0.0552 (13)	0.0292 (15)	0.0053 (10)	0.0027 (15)
C16	0.0679 (16)	0.170 (3)	0.0488 (13)	0.0225 (18)	0.0092 (11)	0.0315 (16)
C17	0.0536 (14)	0.154 (3)	0.0663 (15)	−0.0061 (16)	−0.0019 (11)	−0.0380 (17)

Geometric parameters (Å, º) top

Cl1—C3	1.737 (2)	C8—H8	0.9300
O1—N1	1.233 (8)	C9—C10	1.407 (3)
O2—N1	1.217 (8)	C9—C13	1.511 (2)
O3—C12	1.322 (2)	C10—C11	1.379 (2)
O3—H3	0.8200	C10—H10	0.9300
O1'—N1	1.195 (7)	C11—C12	1.423 (2)
O2'—N1	1.179 (10)	C11—C14	1.537 (3)
N1—C1	1.469 (3)	C13—H13A	0.9600
N2—N3	1.285 (2)	C13—H13B	0.9600
N2—C6	1.413 (2)	C13—H13C	0.9600
N3—C7	1.378 (2)	C14—C17	1.534 (4)
C1—C2	1.382 (3)	C14—C16	1.536 (4)
C1—C6	1.397 (3)	C14—C15	1.540 (3)
C2—C3	1.365 (3)	C15—H15A	0.9600
C2—H2	0.9300	C15—H15B	0.9600
C3—C4	1.381 (3)	C15—H15C	0.9600
C4—C5	1.376 (3)	C16—H16A	0.9600
C4—H4	0.9300	C16—H16B	0.9600
C5—C6	1.392 (3)	C16—H16C	0.9600
C5—H5	0.9300	C17—H17A	0.9600
C7—C8	1.408 (2)	C17—H17B	0.9600
C7—C12	1.429 (3)	C17—H17C	0.9600
C8—C9	1.362 (3)

C12—O3—H3	109.5	C9—C10—H10	117.5
O2'—N1—O1'	119.6 (10)	C10—C11—C12	116.78 (16)
O2—N1—O1	126.8 (8)	C10—C11—C14	122.62 (17)
O2'—N1—C1	118.1 (7)	C12—C11—C14	120.59 (16)
O1'—N1—C1	122.2 (5)	O3—C12—C11	119.79 (16)
O2—N1—C1	116.6 (5)	O3—C12—C7	120.99 (16)
O1—N1—C1	116.4 (6)	C11—C12—C7	119.20 (15)
N3—N2—C6	114.81 (15)	C9—C13—H13A	109.5
N2—N3—C7	116.74 (15)	C9—C13—H13B	109.5
C2—C1—C6	122.12 (19)	H13A—C13—H13B	109.5
C2—C1—N1	116.10 (18)	C9—C13—H13C	109.5
C6—C1—N1	121.77 (17)	H13A—C13—H13C	109.5
C3—C2—C1	118.8 (2)	H13B—C13—H13C	109.5
C3—C2—H2	120.6	C17—C14—C16	111.1 (2)
C1—C2—H2	120.6	C17—C14—C11	109.2 (2)
C2—C3—C4	120.94 (19)	C16—C14—C11	110.12 (19)
C2—C3—Cl1	119.29 (17)	C17—C14—C15	107.7 (2)
C4—C3—Cl1	119.75 (18)	C16—C14—C15	107.5 (2)
C5—C4—C3	119.8 (2)	C11—C14—C15	111.17 (17)
C5—C4—H4	120.1	C14—C15—H15A	109.5
C3—C4—H4	120.1	C14—C15—H15B	109.5
C4—C5—C6	121.11 (19)	H15A—C15—H15B	109.5
C4—C5—H5	119.4	C14—C15—H15C	109.5
C6—C5—H5	119.4	H15A—C15—H15C	109.5
C5—C6—C1	117.11 (17)	H15B—C15—H15C	109.5
C5—C6—N2	122.56 (17)	C14—C16—H16A	109.5
C1—C6—N2	120.32 (17)	C14—C16—H16B	109.5
N3—C7—C8	114.70 (16)	H16A—C16—H16B	109.5
N3—C7—C12	124.97 (16)	C14—C16—H16C	109.5
C8—C7—C12	120.30 (16)	H16A—C16—H16C	109.5
C9—C8—C7	120.93 (17)	H16B—C16—H16C	109.5
C9—C8—H8	119.5	C14—C17—H17A	109.5
C7—C8—H8	119.5	C14—C17—H17B	109.5
C8—C9—C10	117.79 (16)	H17A—C17—H17B	109.5
C8—C9—C13	122.19 (17)	C14—C17—H17C	109.5
C10—C9—C13	120.00 (17)	H17A—C17—H17C	109.5
C11—C10—C9	124.95 (17)	H17B—C17—H17C	109.5
C11—C10—H10	117.5

C6—N2—N3—C7	−179.36 (15)	N2—N3—C7—C8	177.70 (16)
O2'—N1—C1—C2	12 (2)	N2—N3—C7—C12	−0.3 (3)
O1'—N1—C1—C2	−165.3 (16)	N3—C7—C8—C9	−177.44 (18)
O2—N1—C1—C2	−32.9 (10)	C12—C7—C8—C9	0.7 (3)
O1—N1—C1—C2	142.5 (11)	C7—C8—C9—C10	−2.1 (3)
O2'—N1—C1—C6	−168 (2)	C7—C8—C9—C13	176.00 (19)
O1'—N1—C1—C6	14.0 (16)	C8—C9—C10—C11	1.5 (3)
O2—N1—C1—C6	146.4 (10)	C13—C9—C10—C11	−176.6 (2)
O1—N1—C1—C6	−38.2 (11)	C9—C10—C11—C12	0.6 (3)
C6—C1—C2—C3	0.7 (3)	C9—C10—C11—C14	179.5 (2)
N1—C1—C2—C3	−179.9 (2)	C10—C11—C12—O3	176.69 (19)
C1—C2—C3—C4	1.4 (3)	C14—C11—C12—O3	−2.2 (3)
C1—C2—C3—Cl1	−177.30 (16)	C10—C11—C12—C7	−2.0 (3)
C2—C3—C4—C5	−2.0 (3)	C14—C11—C12—C7	179.05 (19)
Cl1—C3—C4—C5	176.67 (17)	N3—C7—C12—O3	0.7 (3)
C3—C4—C5—C6	0.5 (3)	C8—C7—C12—O3	−177.22 (18)
C4—C5—C6—C1	1.5 (3)	N3—C7—C12—C11	179.40 (18)
C4—C5—C6—N2	−177.41 (19)	C8—C7—C12—C11	1.5 (3)
C2—C1—C6—C5	−2.1 (3)	C10—C11—C14—C17	−114.1 (2)
N1—C1—C6—C5	178.6 (2)	C12—C11—C14—C17	64.7 (3)
C2—C1—C6—N2	176.80 (19)	C10—C11—C14—C16	123.6 (2)
N1—C1—C6—N2	−2.5 (3)	C12—C11—C14—C16	−57.5 (3)
N3—N2—C6—C5	0.2 (3)	C10—C11—C14—C15	4.6 (3)
N3—N2—C6—C1	−178.68 (17)	C12—C11—C14—C15	−176.6 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O1′	0.82	2.28	2.933 (7)	136
O3—H3···O1	0.82	2.50	3.142 (12)	136
O3—H3···N2	0.82	1.84	2.553 (2)	145

Experimental details

Crystal data
Chemical formula	C₁₇H₁₈ClN₃O₃
M_r	347.79
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	14.578 (4), 7.0616 (19), 17.043 (5)
β (°)	101.233 (3)
V (Å³)	1720.9 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.24
Crystal size (mm)	0.31 × 0.18 × 0.16

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.930, 0.963
No. of measured, independent and observed [I > 2σ(I)] reflections	14642, 3927, 2563
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.141, 1.03
No. of reflections	3927
No. of parameters	241
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.26

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O1'	0.82	2.28	2.933 (7)	136.4
O3—H3···O1	0.82	2.50	3.142 (12)	136.0
O3—H3···N2	0.82	1.84	2.553 (2)	145.1

Acknowledgements

This work was supported by the National Natural Science Foundation of China (20662007) and the Key Laboratory Open Foundation of Food Science of the Ministry of Education, Nanchang University (NCU200407).

References

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