(3R,4S)-1-(4-Meth­oxy­phen­yl)-2-oxo-4-(3-vinyl­phen­yl)azetidin-3-yl acetate

Hao, X.-D.; Xie, C.; Hao, Y.-P.; Chang, J.; Sun, X.

doi:10.1107/S1600536813007897

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 69| Part 4| April 2013| Page o601

doi:10.1107/S1600536813007897

Open

access

(3R,4S)-1-(4-Methoxyphenyl)-2-oxo-4-(3-vinylphenyl)azetidin-3-yl acetate

Xiao-Dong Hao,^a Cheng Xie,^a Yun-Peng Hao,^a Jun Chang ^a and Xun Sun ^a ^*

^aSchool of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, People's Republic of China
^*Correspondence e-mail: sunxunf@shmu.edu.cn

(Received 24 January 2013; accepted 21 March 2013; online 28 March 2013)

In the title compound, C₂₀H₁₉NO₄, the absolute configuration (3R,4S) for the two chiral centres of the molecule has been determined.

Related literature

For the preparation of the title compound, an intermediate in the synthesis of C-4 to C-3′ bridged paclitaxel analogues, see: Ganesh et al. (2007 ).

Experimental

Crystal data

C₂₀H₁₉NO₄
M_r = 337.36
Monoclinic, C 2
a = 20.7448 (4) Å
b = 6.3930 (1) Å
c = 15.7434 (3) Å
β = 124.309 (1)°
V = 1724.64 (5) Å³
Z = 4
Cu Kα radiation
μ = 0.74 mm⁻¹
T = 124 K
0.20 × 0.18 × 0.11 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2010 ) T_min = 0.866, T_max = 0.923
6072 measured reflections
2374 independent reflections
2330 reflections with I > 2σ(I)
R_int = 0.024

Refinement

R[F² > 2σ(F²)] = 0.026
wR(F²) = 0.069
S = 1.06
2374 reflections
228 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.15 e Å⁻³
Absolute structure: Flack (1983 ), 730 Friedel pairs
Flack parameter: 0.01 (15)

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); 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/S1600536813007897/mw2104sup1.cif

Supporting information file. DOI: 10.1107/S1600536813007897/mw2104Isup2.cdx

Supporting information file. DOI: 10.1107/S1600536813007897/mw2104Isup4.cdx

Structure factors: contains datablock I. DOI: 10.1107/S1600536813007897/mw2104Isup3.hkl

Supporting information file. DOI: 10.1107/S1600536813007897/mw2104Isup5.cml

checkCIF report

Comment top

In our research on the conformation of a novel fluorinated, tubulin-bound, docetaxel analogue, one of the key intermediate products, the title compound (3R,4S)-1-(4-methoxyphenyl)-2-oxo-4-(3-vinylphenyl)azetidin-3-yl acetate C₂₀H₁₉NO₄ (I) (Fig. 1) was separated from the racemic 1-(4-methoxyphenyl)-2-oxo-4-(3-vinylphenyl)azetidin-3-yl acetate (Ganesh et al., 2007). The reaction scheme is shown in Fig. 2. The absolute configuration (3R,4S) for the two chiral centres of the molecule has been determined.

Related literature top

For the preparation of the title compound, an intermediate in the synthesis of C-4 to C-3' bridged paclitaxel analogues, see: Ganesh et al. (2007).

Experimental top

Lipase PS (Amano) (2.25 g) was added to a solution of racemic 1-(4-methoxyphenyl)-2-oxo-4-(3-vinylphenyl)azetidin-3-yl acetate (2.26 g, 6.7 mmol) in 60 mL of CH₃CN and pH 7.0 phosphate buffer (1:9), and the resulting solution was stirred at r.t. for 120 h. The reaction mixture was filtered and extracted with EtOAc (200 mL × 2), the organic layers were combined and solvent was removed under reduced pressure. The residue was purified by flash column chromatography using petroleum ether/EtOAc (4/1) to furnish the title compound (3R,4S)-1-(4-Methoxyphenyl)-2-oxo-4-(3-vinylphenyl)azetidin-3-yl acetate (1 g, 49%) as a white solid. Suitable crystals were obtained by recrystallization from hexane and DCM (m.p. 391.8–392.9 K). ¹H NMR (400 MHz, CDCl₃): δ 1.71 (s, 3H), 3.88 (s, 3H), 5.28 (d, 1H, J = 10.96 Hz), 5.35 (d, 1H, J = 4.69 Hz), 5.75 (d, 1H, J = 17.61 Hz), 5.95 (d, 1H, J = 4.70 Hz), 6.62–6.76 (m, 1H), 6.81 (d, 2H, J = 9 Hz), 7.18–7.42 (m, 6H); ¹³C NMR (100 MHz, CDCl₃): δ 19.85, 55.45, 61.42, 76.32, 114.45, 114.80, 118.82, 125.86, 126.46, 127.28, 128.72, 130.31, 132.73, 136.20, 137.88, 156.66, 161.32, 169.24; ESIMS m/z 338.0 [M + H]⁺.

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); 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. Molecular configuration and atom numbering scheme for (I).
	Fig. 2. Reaction scheme for the synthesis of (I).

(3R,4S)-1-(4-Methoxyphenyl)-2-oxo-4-(3-vinylphenyl)azetidin-3-yl acetate top

Crystal data top

C₂₀H₁₉NO₄	F(000) = 712
M_r = 337.36	D_x = 1.299 Mg m⁻³
Monoclinic, C2	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: C 2y	Cell parameters from 4349 reflections
a = 20.7448 (4) Å	θ = 3.4–66.0°
b = 6.3930 (1) Å	µ = 0.74 mm⁻¹
c = 15.7434 (3) Å	T = 124 K
β = 124.309 (1)°	Block, colourless
V = 1724.64 (5) Å³	0.20 × 0.18 × 0.11 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	2374 independent reflections
Radiation source: fine-focus sealed tube	2330 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.024
ϕ and ω scans	θ_max = 66.3°, θ_min = 3.4°
Absorption correction: multi-scan (SADABS; Bruker, 2010)	h = −24→24
T_min = 0.866, T_max = 0.923	k = −7→6
6072 measured reflections	l = −18→18

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.026	H-atom parameters constrained
wR(F²) = 0.069	w = 1/[σ²(F_o²) + (0.0432P)² + 0.3527P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max = 0.024
2374 reflections	Δρ_max = 0.18 e Å⁻³
228 parameters	Δρ_min = −0.15 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 730 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.01 (15)

Crystal data top

C₂₀H₁₉NO₄	V = 1724.64 (5) Å³
M_r = 337.36	Z = 4
Monoclinic, C2	Cu Kα radiation
a = 20.7448 (4) Å	µ = 0.74 mm⁻¹
b = 6.3930 (1) Å	T = 124 K
c = 15.7434 (3) Å	0.20 × 0.18 × 0.11 mm
β = 124.309 (1)°

Data collection top

Bruker APEXII CCD diffractometer	2374 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2010)	2330 reflections with I > 2σ(I)
T_min = 0.866, T_max = 0.923	R_int = 0.024
6072 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.026	H-atom parameters constrained
wR(F²) = 0.069	Δρ_max = 0.18 e Å⁻³
S = 1.06	Δρ_min = −0.15 e Å⁻³
2374 reflections	Absolute structure: Flack (1983), 730 Friedel pairs
228 parameters	Absolute structure parameter: 0.01 (15)
1 restraint

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
N1	0.01643 (6)	0.3030 (2)	0.64077 (8)	0.0200 (3)
O1	−0.02784 (6)	0.65258 (18)	0.59931 (8)	0.0270 (2)
O2	−0.06828 (5)	0.45389 (17)	0.74357 (7)	0.0222 (2)
O3	−0.15201 (7)	0.2201 (2)	0.73583 (9)	0.0383 (3)
O4	0.26072 (6)	0.13686 (18)	0.59965 (8)	0.0273 (2)
C1	−0.02761 (7)	0.4753 (3)	0.62602 (10)	0.0211 (3)
C2	−0.07416 (7)	0.3539 (2)	0.65865 (10)	0.0211 (3)
H2	−0.1292	0.3251	0.6003	0.025*
C3	−0.01748 (7)	0.1671 (2)	0.68246 (10)	0.0207 (3)
H3	−0.0451	0.0426	0.6380	0.025*
C4	0.03811 (7)	0.1098 (2)	0.79424 (10)	0.0211 (3)
C5	0.02826 (8)	−0.0778 (3)	0.82961 (12)	0.0296 (3)
H5	−0.0121	−0.1714	0.7832	0.035*
C6	0.07760 (9)	−0.1290 (3)	0.93339 (12)	0.0390 (4)
H6	0.0704	−0.2572	0.9576	0.047*
C7	0.13680 (9)	0.0046 (3)	1.00140 (12)	0.0360 (4)
H7	0.1695	−0.0314	1.0722	0.043*
C8	0.14908 (8)	0.1925 (3)	0.96712 (11)	0.0269 (3)
C9	0.09860 (8)	0.2431 (3)	0.86306 (11)	0.0229 (3)
H9	0.1057	0.3711	0.8387	0.028*
C10	0.21420 (9)	0.3354 (3)	1.03509 (12)	0.0332 (4)
H10	0.2162	0.4619	1.0050	0.040*
C11	0.26974 (10)	0.3070 (4)	1.13267 (14)	0.0499 (5)
H11A	0.2706	0.1832	1.1667	0.060*
H11B	0.3090	0.4102	1.1692	0.060*
C12	−0.11309 (8)	0.3737 (3)	0.77324 (12)	0.0272 (3)
C13	−0.10664 (12)	0.5031 (4)	0.85648 (14)	0.0436 (5)
H13A	−0.1589	0.5291	0.8408	0.065*
H13B	−0.0816	0.6367	0.8613	0.065*
H13C	−0.0752	0.4286	0.9221	0.065*
C14	0.07884 (7)	0.2651 (2)	0.63024 (9)	0.0191 (3)
C15	0.09304 (7)	0.0624 (2)	0.61245 (10)	0.0224 (3)
H15	0.0609	−0.0497	0.6071	0.027*
C16	0.15445 (8)	0.0252 (2)	0.60258 (11)	0.0244 (3)
H16	0.1643	−0.1127	0.5902	0.029*
C17	0.20168 (8)	0.1904 (2)	0.61088 (10)	0.0210 (3)
C18	0.18780 (8)	0.3919 (3)	0.62910 (11)	0.0239 (3)
H18	0.2203	0.5038	0.6353	0.029*
C19	0.12576 (8)	0.4292 (3)	0.63829 (10)	0.0236 (3)
H19	0.1156	0.5673	0.6501	0.028*
C20	0.30559 (8)	0.3045 (3)	0.59786 (13)	0.0295 (3)
H20A	0.2707	0.4030	0.5431	0.044*
H20B	0.3433	0.2482	0.5850	0.044*
H20C	0.3335	0.3771	0.6642	0.044*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0204 (5)	0.0178 (6)	0.0214 (5)	−0.0002 (5)	0.0116 (4)	0.0004 (5)
O1	0.0313 (5)	0.0195 (6)	0.0351 (5)	0.0038 (4)	0.0218 (5)	0.0041 (5)
O2	0.0229 (4)	0.0220 (6)	0.0253 (5)	−0.0024 (4)	0.0159 (4)	−0.0037 (4)
O3	0.0451 (6)	0.0320 (7)	0.0505 (7)	−0.0147 (6)	0.0347 (6)	−0.0096 (6)
O4	0.0284 (5)	0.0215 (6)	0.0406 (5)	−0.0004 (4)	0.0247 (4)	−0.0021 (5)
C1	0.0200 (6)	0.0215 (8)	0.0202 (6)	0.0002 (5)	0.0105 (5)	−0.0017 (6)
C2	0.0210 (6)	0.0212 (8)	0.0206 (6)	0.0000 (6)	0.0116 (5)	−0.0020 (6)
C3	0.0210 (6)	0.0193 (8)	0.0238 (6)	−0.0015 (5)	0.0138 (5)	−0.0010 (6)
C4	0.0207 (6)	0.0206 (8)	0.0245 (7)	0.0014 (5)	0.0143 (5)	0.0010 (6)
C5	0.0266 (7)	0.0272 (9)	0.0322 (7)	−0.0042 (6)	0.0149 (6)	0.0028 (7)
C6	0.0380 (8)	0.0379 (11)	0.0357 (8)	−0.0049 (8)	0.0176 (7)	0.0149 (9)
C7	0.0289 (8)	0.0483 (12)	0.0268 (7)	0.0004 (7)	0.0133 (6)	0.0107 (8)
C8	0.0217 (7)	0.0350 (10)	0.0245 (7)	0.0005 (6)	0.0133 (6)	0.0001 (7)
C9	0.0230 (6)	0.0228 (8)	0.0260 (7)	0.0000 (6)	0.0156 (6)	0.0013 (6)
C10	0.0278 (7)	0.0408 (11)	0.0300 (7)	−0.0045 (7)	0.0157 (6)	−0.0031 (8)
C11	0.0360 (9)	0.0674 (15)	0.0308 (8)	−0.0154 (9)	0.0094 (7)	−0.0001 (10)
C12	0.0281 (7)	0.0256 (9)	0.0331 (7)	−0.0024 (7)	0.0204 (6)	−0.0017 (7)
C13	0.0543 (10)	0.0499 (13)	0.0450 (9)	−0.0151 (9)	0.0392 (9)	−0.0142 (9)
C14	0.0195 (6)	0.0203 (8)	0.0170 (6)	0.0018 (5)	0.0099 (5)	0.0019 (6)
C15	0.0236 (6)	0.0186 (8)	0.0251 (7)	−0.0012 (6)	0.0138 (6)	0.0021 (6)
C16	0.0281 (7)	0.0167 (8)	0.0308 (7)	0.0020 (6)	0.0180 (6)	−0.0006 (6)
C17	0.0201 (6)	0.0219 (8)	0.0215 (6)	0.0016 (5)	0.0119 (5)	0.0008 (6)
C18	0.0230 (6)	0.0198 (8)	0.0295 (7)	−0.0030 (6)	0.0153 (6)	−0.0013 (7)
C19	0.0244 (6)	0.0178 (8)	0.0282 (7)	0.0004 (6)	0.0147 (6)	−0.0037 (6)
C20	0.0267 (7)	0.0256 (8)	0.0433 (8)	0.0009 (6)	0.0240 (7)	0.0048 (7)

Geometric parameters (Å, º) top

N1—C1	1.365 (2)	C8—C10	1.475 (2)
N1—C14	1.4157 (17)	C9—H9	0.9500
N1—C3	1.4834 (18)	C10—C11	1.313 (2)
O1—C1	1.208 (2)	C10—H10	0.9500
O2—C12	1.3547 (18)	C11—H11A	0.9500
O2—C2	1.4237 (17)	C11—H11B	0.9500
O3—C12	1.194 (2)	C12—C13	1.491 (2)
O4—C17	1.3760 (16)	C13—H13A	0.9800
O4—C20	1.4300 (19)	C13—H13B	0.9800
C1—C2	1.535 (2)	C13—H13C	0.9800
C2—C3	1.566 (2)	C14—C19	1.387 (2)
C2—H2	1.0000	C14—C15	1.392 (2)
C3—C4	1.5077 (19)	C15—C16	1.388 (2)
C3—H3	1.0000	C15—H15	0.9500
C4—C5	1.385 (2)	C16—C17	1.396 (2)
C4—C9	1.393 (2)	C16—H16	0.9500
C5—C6	1.392 (2)	C17—C18	1.385 (2)
C5—H5	0.9500	C18—C19	1.394 (2)
C6—C7	1.379 (3)	C18—H18	0.9500
C6—H6	0.9500	C19—H19	0.9500
C7—C8	1.398 (3)	C20—H20A	0.9800
C7—H7	0.9500	C20—H20B	0.9800
C8—C9	1.397 (2)	C20—H20C	0.9800

C1—N1—C14	133.38 (13)	C11—C10—H10	116.4
C1—N1—C3	96.24 (11)	C8—C10—H10	116.4
C14—N1—C3	130.15 (13)	C10—C11—H11A	120.0
C12—O2—C2	116.20 (12)	C10—C11—H11B	120.0
C17—O4—C20	116.91 (12)	H11A—C11—H11B	120.0
O1—C1—N1	133.42 (13)	O3—C12—O2	123.08 (14)
O1—C1—C2	135.29 (13)	O3—C12—C13	126.19 (15)
N1—C1—C2	91.28 (12)	O2—C12—C13	110.73 (14)
O2—C2—C1	110.50 (12)	C12—C13—H13A	109.5
O2—C2—C3	117.53 (11)	C12—C13—H13B	109.5
C1—C2—C3	86.35 (10)	H13A—C13—H13B	109.5
O2—C2—H2	113.2	C12—C13—H13C	109.5
C1—C2—H2	113.2	H13A—C13—H13C	109.5
C3—C2—H2	113.2	H13B—C13—H13C	109.5
N1—C3—C4	114.66 (11)	C19—C14—C15	120.34 (12)
N1—C3—C2	85.81 (11)	C19—C14—N1	120.06 (14)
C4—C3—C2	116.23 (12)	C15—C14—N1	119.60 (13)
N1—C3—H3	112.5	C16—C15—C14	119.60 (14)
C4—C3—H3	112.5	C16—C15—H15	120.2
C2—C3—H3	112.5	C14—C15—H15	120.2
C5—C4—C9	119.27 (13)	C15—C16—C17	119.98 (14)
C5—C4—C3	119.38 (13)	C15—C16—H16	120.0
C9—C4—C3	121.34 (14)	C17—C16—H16	120.0
C4—C5—C6	119.86 (15)	O4—C17—C18	124.20 (13)
C4—C5—H5	120.1	O4—C17—C16	115.37 (13)
C6—C5—H5	120.1	C18—C17—C16	120.42 (13)
C7—C6—C5	120.61 (16)	C17—C18—C19	119.50 (14)
C7—C6—H6	119.7	C17—C18—H18	120.2
C5—C6—H6	119.7	C19—C18—H18	120.2
C6—C7—C8	120.59 (14)	C14—C19—C18	120.15 (15)
C6—C7—H7	119.7	C14—C19—H19	119.9
C8—C7—H7	119.7	C18—C19—H19	119.9
C9—C8—C7	118.18 (14)	O4—C20—H20A	109.5
C9—C8—C10	118.85 (15)	O4—C20—H20B	109.5
C7—C8—C10	122.94 (14)	H20A—C20—H20B	109.5
C4—C9—C8	121.45 (15)	O4—C20—H20C	109.5
C4—C9—H9	119.3	H20A—C20—H20C	109.5
C8—C9—H9	119.3	H20B—C20—H20C	109.5
C11—C10—C8	127.16 (19)

C14—N1—C1—O1	−0.2 (3)	C6—C7—C8—C9	1.7 (2)
C3—N1—C1—O1	174.55 (16)	C6—C7—C8—C10	−176.31 (17)
C14—N1—C1—C2	−179.17 (13)	C5—C4—C9—C8	−0.6 (2)
C3—N1—C1—C2	−4.44 (11)	C3—C4—C9—C8	178.51 (13)
C12—O2—C2—C1	173.69 (12)	C7—C8—C9—C4	−0.9 (2)
C12—O2—C2—C3	−89.52 (15)	C10—C8—C9—C4	177.16 (14)
O1—C1—C2—O2	−56.7 (2)	C9—C8—C10—C11	−175.47 (18)
N1—C1—C2—O2	122.26 (11)	C7—C8—C10—C11	2.5 (3)
O1—C1—C2—C3	−174.77 (17)	C2—O2—C12—O3	4.6 (2)
N1—C1—C2—C3	4.19 (10)	C2—O2—C12—C13	−175.14 (14)
C1—N1—C3—C4	−112.63 (13)	C1—N1—C14—C19	24.9 (2)
C14—N1—C3—C4	62.36 (19)	C3—N1—C14—C19	−148.25 (14)
C1—N1—C3—C2	4.37 (11)	C1—N1—C14—C15	−155.51 (14)
C14—N1—C3—C2	179.35 (13)	C3—N1—C14—C15	31.4 (2)
O2—C2—C3—N1	−115.12 (12)	C19—C14—C15—C16	−0.1 (2)
C1—C2—C3—N1	−3.86 (10)	N1—C14—C15—C16	−179.71 (12)
O2—C2—C3—C4	0.37 (19)	C14—C15—C16—C17	0.2 (2)
C1—C2—C3—C4	111.62 (13)	C20—O4—C17—C18	−5.7 (2)
N1—C3—C4—C5	−151.25 (14)	C20—O4—C17—C16	174.20 (12)
C2—C3—C4—C5	110.90 (16)	C15—C16—C17—O4	−179.83 (12)
N1—C3—C4—C9	29.63 (19)	C15—C16—C17—C18	0.1 (2)
C2—C3—C4—C9	−68.22 (17)	O4—C17—C18—C19	179.39 (12)
C9—C4—C5—C6	1.4 (2)	C16—C17—C18—C19	−0.5 (2)
C3—C4—C5—C6	−177.79 (14)	C15—C14—C19—C18	−0.3 (2)
C4—C5—C6—C7	−0.6 (3)	N1—C14—C19—C18	179.28 (12)
C5—C6—C7—C8	−0.9 (3)	C17—C18—C19—C14	0.6 (2)

Experimental details

Crystal data
Chemical formula	C₂₀H₁₉NO₄
M_r	337.36
Crystal system, space group	Monoclinic, C2
Temperature (K)	124
a, b, c (Å)	20.7448 (4), 6.3930 (1), 15.7434 (3)
β (°)	124.309 (1)
V (Å³)	1724.64 (5)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	0.74
Crystal size (mm)	0.20 × 0.18 × 0.11

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2010)
T_min, T_max	0.866, 0.923
No. of measured, independent and observed [I > 2σ(I)] reflections	6072, 2374, 2330
R_int	0.024
(sin θ/λ)_max (Å⁻¹)	0.594

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.026, 0.069, 1.06
No. of reflections	2374
No. of parameters	228
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.15
Absolute structure	Flack (1983), 730 Friedel pairs
Absolute structure parameter	0.01 (15)

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

The work was supported financially by the National Natural Science Foundation of China (No. 81172920), the Shanghai Municipal Committee of Science and Technology (No. 10431903100) and the National Basic Research Program of China (973 Program, No. 2010CB912603). We would like to thank Dr Jie Sun for the single-crystal X-ray determination.

References

Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Ganesh, T., Yang, C., Norris, A., Glass, T., Bane, S., Ravindra, R., Banerjee, A., Metaferia, B., Thomas, S. L. & Giannakakou, P. (2007). J. Med. Chem. 50, 713–725. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar