(4R*,5R*)-Diethyl 2-(4-nitro­phen­yl)-1,3-dioxolane-4,5-dicarboxyl­ate

Lv, C.-L.; Chen, J.-H.; Zhang, Y.-Z.; Lu, D.-Q.; OuYang, P.-K.

doi:10.1107/S160053681201118X

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 4| April 2012| Page o1128

doi:10.1107/S160053681201118X

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(4R,5R)-Diethyl 2-(4-nitrophenyl)-1,3-dioxolane-4,5-dicarboxylate

Chun-Lei Lv,^a,^b Jian-Hui Chen,^a,^b Yu-Zhe Zhang,^c Ding-Qiang Lu ^a ^* and Ping-Kai OuYang ^a

^aSchool of Pharmaceutical Science, Nanjing University of Technology, Xinmofan Road No. 5 Nanjing, Nanjing 210009, People's Republic of China, ^bXinchang Pharmaceutical Factory, Zhejiang Medicine Co. Ltd, Xinchang 312500, People's Republic of China, and ^cCollege of Materials Science and Engineering, Nanjing University of Technology, Xinmofan Road No. 5 Nanjing, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: ludingqiang@126.com

(Received 25 February 2012; accepted 14 March 2012; online 21 March 2012)

In the title compound, C₁₅H₁₇NO₈, the nitro group is essentially coplanar with the aromatic ring [dihedral angle = 6.4 (3) Å]. The five-membered ring has a twist conformation. In the crystal, C—H⋯O interactions link the molecules into a helical chain propagating along [010].

Related literature

For the synthesis of the title compound, see: Kim et al. (1994 ). For the use of (2S,3S)-diethyl 2,3-O-alkyltartrate analogues as intermediates in organic synthesis, see: Pandey et al. (1997 ). For typical bond-length data, see: Allen et al. (1987 ).

Experimental

Crystal data

C₁₅H₁₇NO₈
M_r = 339.30
Monoclinic, P 2₁
a = 12.261 (3) Å
b = 4.5200 (9) Å
c = 15.656 (3) Å
β = 112.27 (3)°
V = 802.9 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.10 mm

Data collection

Enraf-Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.966, T_max = 0.989
3062 measured reflections
1660 independent reflections
1364 reflections with I > 2σ(I)
R_int = 0.017
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.046
wR(F²) = 0.142
S = 1.01
1660 reflections
218 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C12—H12A⋯O8ⁱ	0.96	2.50	3.356 (7)	149
Symmetry code: (i) $[-x+1, y-{\script{1\over 2}}, -z]$ .

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681201118X/su2384sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681201118X/su2384Isup2.hkl

Supporting information file. DOI: 10.1107/S160053681201118X/su2384Isup3.cml

checkCIF report

Comment top

Antitumor platinum drugs are one of the most effective anticancer agents currently available. (2S,3S)-Diethyl 2,3-O-alkyltartrate analogues are starting materials for the synthesis of platinum complexes with antitumor activity (Kim et al., 1994), and they are also important intermediates in organic synthesis (Pandey et al., 1997). As part of our studies of the synthesis and characterization of such compounds, we herein report on the crystal structure of the title compound.

The molecular structure of the title compound is shown in Fig. 1. The bond lengths are within normal ranges (Allen et al., 1987). The nitro group (N1/O1/O2) is essentially coplanar with the aromatic ring (C1-C6) being inclined to it by 6.4 (3)°. The five-membered ring (O3/O4/C7-C9) has a twist conformation on bond O4-C8.

In the crystal, a C—H···O interaction (Table 1) links the molecules to form a a helical chain propagating along the b axis direction (Fig. 2).

Related literature top

For the synthesis of the title compound, see: Kim et al. (1994). For the use of (2S,3S)-diethyl 2,3-O-alkyltartrate analogues as intermediates in organic synthesis, see: Pandey et al. (1997). For typical bond-length data, see: Allen et al. (1987).

Experimental top

4-Nitrobenzaldehyde (299 mg, 1.98 mmol), (2S,3S)-diethyltartrate (378 mg, 1.84 mmol) and cyclohexane (10 ml) were placed in a round-bottomed flask, and 30 mg of 4-methylbenzenesulfonic acid was added. The flask was fitted with a water distributor. The mixture was heated under reflux for 4 h. The reaction mixture was then added dropwise to water (600 ml) with vigorous stirring. A pale yellow precipitate was obtained, filtered off and dried in vacuo. Colourless block-like crystals, suitable for X-ray analysis, were obtained by slow evaporation of a methanol solution after 4 weeks.

Structure description top

In the crystal, a C—H···O interaction (Table 1) links the molecules to form a a helical chain propagating along the b axis direction (Fig. 2).

For the synthesis of the title compound, see: Kim et al. (1994). For the use of (2S,3S)-diethyl 2,3-O-alkyltartrate analogues as intermediates in organic synthesis, see: Pandey et al. (1997). For typical bond-length data, see: Allen et al. (1987).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound showing the atom-numbering. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A view along the b axis of the crystal packing of the title compound, with the C-H···O interactions shown as dashed lines.

(4R*,5R*)-Diethyl 2-(4-nitrophenyl)-1,3-dioxolane-4,5-dicarboxylate top

Crystal data top

C₁₅H₁₇NO₈	F(000) = 356
M_r = 339.30	D_x = 1.403 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 12.261 (3) Å	θ = 9–13°
b = 4.5200 (9) Å	µ = 0.12 mm⁻¹
c = 15.656 (3) Å	T = 293 K
β = 112.27 (3)°	Block, colourless
V = 802.9 (3) Å³	0.30 × 0.20 × 0.10 mm
Z = 2

Data collection top

Enraf-Nonius CAD-4 diffractometer	1364 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.017
Graphite monochromator	θ_max = 25.3°, θ_min = 1.4°
ω/2θ scans	h = 0→14
Absorption correction: ψ scan (North et al., 1968)	k = −5→5
T_min = 0.966, T_max = 0.989	l = −18→17
3062 measured reflections	3 standard reflections every 200 reflections
1660 independent reflections	intensity decay: 1%

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)] = 0.046	H-atom parameters constrained
wR(F²) = 0.142	w = 1/[σ²(F_o²) + (0.1P)² + 0.070P] where P = (F_o² + 2F_c²)/3
S = 1.01	(Δ/σ)_max < 0.001
1660 reflections	Δρ_max = 0.21 e Å⁻³
218 parameters	Δρ_min = −0.16 e Å⁻³
1 restraint	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.036 (9)

Crystal data top

C₁₅H₁₇NO₈	V = 802.9 (3) Å³
M_r = 339.30	Z = 2
Monoclinic, P2₁	Mo Kα radiation
a = 12.261 (3) Å	µ = 0.12 mm⁻¹
b = 4.5200 (9) Å	T = 293 K
c = 15.656 (3) Å	0.30 × 0.20 × 0.10 mm
β = 112.27 (3)°

Data collection top

Enraf-Nonius CAD-4 diffractometer	1364 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.017
T_min = 0.966, T_max = 0.989	3 standard reflections every 200 reflections
3062 measured reflections	intensity decay: 1%
1660 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.046	1 restraint
wR(F²) = 0.142	H-atom parameters constrained
S = 1.01	Δρ_max = 0.21 e Å⁻³
1660 reflections	Δρ_min = −0.16 e Å⁻³
218 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
N1	0.1597 (5)	0.1051 (17)	0.6035 (3)	0.1016 (18)
C1	0.3496 (4)	−0.1471 (14)	0.4814 (3)	0.0770 (14)
H1A	0.4154	−0.2670	0.4932	0.092*
O1	0.0820 (6)	0.276 (2)	0.5904 (4)	0.163 (3)
C2	0.3039 (4)	−0.1052 (17)	0.5489 (3)	0.0902 (18)
H2A	0.3396	−0.1929	0.6066	0.108*
O2	0.2028 (4)	−0.0395 (18)	0.6735 (3)	0.146 (3)
O3	0.26487 (19)	−0.1203 (6)	0.23682 (14)	0.0483 (6)
C3	0.2075 (4)	0.0631 (14)	0.5303 (3)	0.0703 (12)
O4	0.40116 (19)	0.2240 (6)	0.31395 (14)	0.0465 (6)
C4	0.1556 (4)	0.2006 (17)	0.4495 (3)	0.0924 (19)
H4A	0.0895	0.3184	0.4387	0.111*
O5	0.5315 (2)	0.1545 (8)	0.14859 (18)	0.0685 (8)
C5	0.2020 (4)	0.1647 (15)	0.3817 (3)	0.0855 (17)
H5A	0.1675	0.2616	0.3254	0.103*
C6	0.2981 (3)	−0.0121 (9)	0.3972 (2)	0.0490 (9)
O6	0.5589 (3)	−0.1270 (9)	0.2711 (2)	0.0884 (11)
C7	0.3507 (3)	−0.0501 (8)	0.3259 (2)	0.0469 (8)
H7A	0.4116	−0.2038	0.3455	0.056*
C8	0.4003 (3)	0.2225 (8)	0.2239 (2)	0.0445 (8)
H8A	0.3970	0.4254	0.2010	0.053*
O7	0.1014 (2)	0.2755 (6)	0.15578 (16)	0.0555 (7)
C9	0.2829 (3)	0.0569 (8)	0.1691 (2)	0.0452 (8)
H9A	0.2942	−0.0709	0.1226	0.054*
O8	0.1850 (2)	0.4257 (7)	0.05872 (16)	0.0650 (8)
C10	0.5053 (3)	0.0613 (9)	0.2180 (3)	0.0525 (9)
C11	0.6333 (4)	0.0176 (15)	0.1381 (3)	0.0895 (16)
H11A	0.6229	−0.1952	0.1325	0.107*
H11B	0.7040	0.0595	0.1917	0.107*
C12	0.6445 (5)	0.1387 (18)	0.0547 (4)	0.107 (2)
H12A	0.7100	0.0469	0.0457	0.161*
H12B	0.6573	0.3484	0.0616	0.161*
H12C	0.5735	0.1000	0.0022	0.161*
C13	0.1838 (3)	0.2735 (8)	0.1218 (2)	0.0449 (8)
C14	0.0027 (4)	0.4800 (12)	0.1144 (3)	0.0712 (12)
H14A	0.0301	0.6610	0.0960	0.085*
H14B	−0.0562	0.3910	0.0601	0.085*
C15	−0.0484 (5)	0.5452 (19)	0.1824 (4)	0.117 (2)
H15A	−0.1132	0.6799	0.1563	0.175*
H15B	0.0103	0.6335	0.2359	0.175*
H15C	−0.0761	0.3653	0.1998	0.175*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.105 (3)	0.139 (5)	0.084 (3)	−0.026 (4)	0.062 (3)	−0.016 (3)
C1	0.071 (2)	0.095 (4)	0.068 (2)	0.019 (3)	0.030 (2)	0.030 (3)
O1	0.183 (5)	0.223 (8)	0.135 (4)	0.052 (7)	0.119 (4)	0.004 (5)
C2	0.093 (3)	0.125 (5)	0.056 (2)	0.000 (4)	0.032 (2)	0.028 (3)
O2	0.176 (4)	0.200 (7)	0.094 (2)	−0.031 (5)	0.089 (3)	0.015 (4)
O3	0.0611 (13)	0.0358 (12)	0.0482 (12)	−0.0079 (12)	0.0209 (10)	−0.0006 (10)
C3	0.073 (2)	0.091 (3)	0.056 (2)	−0.022 (3)	0.0355 (19)	−0.011 (2)
O4	0.0525 (12)	0.0379 (13)	0.0504 (12)	−0.0032 (11)	0.0208 (9)	−0.0071 (11)
C4	0.088 (3)	0.130 (5)	0.072 (3)	0.036 (4)	0.045 (2)	0.007 (4)
O5	0.0702 (16)	0.073 (2)	0.0773 (16)	0.0163 (16)	0.0448 (13)	0.0028 (16)
C5	0.090 (3)	0.112 (5)	0.060 (2)	0.045 (3)	0.036 (2)	0.021 (3)
C6	0.0488 (17)	0.048 (2)	0.0468 (17)	−0.0029 (17)	0.0141 (14)	0.0011 (16)
O6	0.090 (2)	0.078 (2)	0.117 (2)	0.034 (2)	0.0619 (19)	0.033 (2)
C7	0.0506 (17)	0.0374 (18)	0.0508 (17)	0.0003 (16)	0.0169 (14)	0.0011 (15)
C8	0.0494 (17)	0.0367 (17)	0.0495 (16)	−0.0036 (16)	0.0212 (14)	−0.0032 (16)
O7	0.0547 (13)	0.0584 (17)	0.0582 (13)	0.0070 (13)	0.0267 (11)	0.0119 (13)
C9	0.0597 (19)	0.0338 (17)	0.0486 (16)	−0.0033 (16)	0.0279 (15)	−0.0046 (15)
O8	0.0735 (16)	0.071 (2)	0.0550 (13)	0.0023 (16)	0.0290 (12)	0.0172 (15)
C10	0.058 (2)	0.043 (2)	0.062 (2)	−0.0007 (19)	0.0291 (17)	−0.0052 (19)
C11	0.090 (3)	0.095 (4)	0.109 (3)	0.022 (3)	0.066 (3)	−0.007 (3)
C12	0.112 (4)	0.124 (6)	0.118 (4)	0.014 (4)	0.081 (3)	−0.009 (4)
C13	0.0490 (17)	0.0425 (19)	0.0401 (15)	−0.0088 (15)	0.0135 (14)	−0.0045 (15)
C14	0.061 (2)	0.073 (3)	0.078 (3)	0.017 (2)	0.0242 (19)	0.014 (2)
C15	0.100 (4)	0.136 (7)	0.133 (4)	0.057 (5)	0.065 (3)	0.027 (5)

Geometric parameters (Å, º) top

N1—O1	1.183 (9)	C7—H7A	0.9800
N1—O2	1.212 (8)	C8—C10	1.512 (5)
N1—C3	1.483 (6)	C8—C9	1.560 (4)
C1—C6	1.370 (5)	C8—H8A	0.9800
C1—C2	1.384 (6)	O7—C13	1.309 (4)
C1—H1A	0.9300	O7—C14	1.465 (5)
C2—C3	1.341 (8)	C9—C13	1.517 (5)
C2—H2A	0.9300	C9—H9A	0.9800
O3—C9	1.411 (4)	O8—C13	1.208 (4)
O3—C7	1.428 (4)	C11—C12	1.470 (7)
C3—C4	1.335 (7)	C11—H11A	0.9700
O4—C8	1.406 (4)	C11—H11B	0.9700
O4—C7	1.428 (4)	C12—H12A	0.9600
C4—C5	1.391 (6)	C12—H12B	0.9600
C4—H4A	0.9300	C12—H12C	0.9600
O5—C10	1.314 (5)	C14—C15	1.455 (7)
O5—C11	1.458 (5)	C14—H14A	0.9700
C5—C6	1.367 (6)	C14—H14B	0.9700
C5—H5A	0.9300	C15—H15A	0.9600
C6—C7	1.497 (5)	C15—H15B	0.9600
O6—C10	1.197 (5)	C15—H15C	0.9600

O1—N1—O2	123.7 (5)	O3—C9—C13	114.1 (3)
O1—N1—C3	118.6 (6)	O3—C9—C8	103.5 (2)
O2—N1—C3	117.7 (6)	C13—C9—C8	111.1 (3)
C6—C1—C2	120.0 (5)	O3—C9—H9A	109.3
C6—C1—H1A	120.0	C13—C9—H9A	109.3
C2—C1—H1A	120.0	C8—C9—H9A	109.3
C3—C2—C1	119.4 (4)	O6—C10—O5	124.1 (4)
C3—C2—H2A	120.3	O6—C10—C8	123.8 (3)
C1—C2—H2A	120.3	O5—C10—C8	112.1 (3)
C9—O3—C7	109.9 (3)	O5—C11—C12	108.3 (4)
C4—C3—C2	122.3 (4)	O5—C11—H11A	110.0
C4—C3—N1	119.1 (5)	C12—C11—H11A	110.0
C2—C3—N1	118.6 (5)	O5—C11—H11B	110.0
C8—O4—C7	106.7 (3)	C12—C11—H11B	110.0
C3—C4—C5	118.9 (5)	H11A—C11—H11B	108.4
C3—C4—H4A	120.6	C11—C12—H12A	109.5
C5—C4—H4A	120.6	C11—C12—H12B	109.5
C10—O5—C11	116.5 (4)	H12A—C12—H12B	109.5
C6—C5—C4	120.4 (4)	C11—C12—H12C	109.5
C6—C5—H5A	119.8	H12A—C12—H12C	109.5
C4—C5—H5A	119.8	H12B—C12—H12C	109.5
C5—C6—C1	118.9 (4)	O8—C13—O7	125.3 (3)
C5—C6—C7	121.4 (3)	O8—C13—C9	120.8 (3)
C1—C6—C7	119.7 (3)	O7—C13—C9	113.9 (3)
O4—C7—O3	105.1 (3)	C15—C14—O7	108.5 (4)
O4—C7—C6	109.2 (3)	C15—C14—H14A	110.0
O3—C7—C6	112.8 (3)	O7—C14—H14A	110.0
O4—C7—H7A	109.9	C15—C14—H14B	110.0
O3—C7—H7A	109.9	O7—C14—H14B	110.0
C6—C7—H7A	109.9	H14A—C14—H14B	108.4
O4—C8—C10	112.4 (3)	C14—C15—H15A	109.5
O4—C8—C9	102.0 (2)	C14—C15—H15B	109.5
C10—C8—C9	111.4 (3)	H15A—C15—H15B	109.5
O4—C8—H8A	110.3	C14—C15—H15C	109.5
C10—C8—H8A	110.3	H15A—C15—H15C	109.5
C9—C8—H8A	110.3	H15B—C15—H15C	109.5
C13—O7—C14	117.5 (3)

C6—C1—C2—C3	1.4 (9)	C7—O4—C8—C10	−83.6 (3)
C1—C2—C3—C4	−2.1 (10)	C7—O4—C8—C9	35.8 (3)
C1—C2—C3—N1	179.9 (6)	C7—O3—C9—C13	−114.2 (3)
O1—N1—C3—C4	−5.3 (10)	C7—O3—C9—C8	6.7 (3)
O2—N1—C3—C4	174.5 (6)	O4—C8—C9—O3	−25.9 (3)
O1—N1—C3—C2	172.7 (7)	C10—C8—C9—O3	94.2 (3)
O2—N1—C3—C2	−7.5 (9)	O4—C8—C9—C13	97.1 (3)
C2—C3—C4—C5	0.9 (10)	C10—C8—C9—C13	−142.9 (3)
N1—C3—C4—C5	178.9 (6)	C11—O5—C10—O6	−0.6 (6)
C3—C4—C5—C6	1.0 (10)	C11—O5—C10—C8	178.6 (4)
C4—C5—C6—C1	−1.6 (9)	O4—C8—C10—O6	24.7 (5)
C4—C5—C6—C7	−179.0 (5)	C9—C8—C10—O6	−89.0 (4)
C2—C1—C6—C5	0.5 (8)	O4—C8—C10—O5	−154.5 (3)
C2—C1—C6—C7	177.8 (5)	C9—C8—C10—O5	91.7 (4)
C8—O4—C7—O3	−32.8 (3)	C10—O5—C11—C12	177.1 (5)
C8—O4—C7—C6	−154.0 (2)	C14—O7—C13—O8	−0.4 (5)
C9—O3—C7—O4	14.8 (3)	C14—O7—C13—C9	179.6 (3)
C9—O3—C7—C6	133.7 (3)	O3—C9—C13—O8	−175.6 (3)
C5—C6—C7—O4	67.0 (5)	C8—C9—C13—O8	67.8 (4)
C1—C6—C7—O4	−110.3 (4)	O3—C9—C13—O7	4.4 (4)
C5—C6—C7—O3	−49.4 (5)	C8—C9—C13—O7	−112.2 (3)
C1—C6—C7—O3	133.3 (4)	C13—O7—C14—C15	−155.4 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12A···O8ⁱ	0.96	2.50	3.356 (7)	149

Symmetry code: (i) −x+1, y−1/2, −z.

Experimental details

Crystal data
Chemical formula	C₁₅H₁₇NO₈
M_r	339.30
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	293
a, b, c (Å)	12.261 (3), 4.5200 (9), 15.656 (3)
β (°)	112.27 (3)
V (Å³)	802.9 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.30 × 0.20 × 0.10

Data collection
Diffractometer	Enraf-Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.966, 0.989
No. of measured, independent and observed [I > 2σ(I)] reflections	3062, 1660, 1364
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.602

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.142, 1.01
No. of reflections	1660
No. of parameters	218
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.16

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12A···O8ⁱ	0.96	2.50	3.356 (7)	149

Symmetry code: (i) −x+1, y−1/2, −z.

Acknowledgements

The authors thank Liu Bo Nian from Nanjing University of Technology for useful discussions and the Center of Testing and Analysis, Nanjing University, for their support.

References

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Enraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands. Google Scholar
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