Ethyl 4-acetamido-3-acet­oxy-2-benzyl-3-methyl­butano­ate

Wang, G.L.; Zhang, J.M.; Zhang, X.; Xu, H.; Duan, G.Y.

doi:10.1107/S1600536811049440

organic compounds

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ISSN: 2056-9890

Volume 67| Part 12| December 2011| Page o3418

https://doi.org/10.1107/S1600536811049440

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Ethyl 4-acetamido-3-acetoxy-2-benzyl-3-methylbutanoate

Guang Liang Wang,^a Ji Mei Zhang,^a Xin Zhang,^a Hao Xu ^a and Gui Yun Duan ^a ^*

^aTaishan Medical College, Tai an 271016, People's Republic of China
^*Correspondence e-mail: yqge@yahoo.cn

(Received 21 September 2011; accepted 19 November 2011; online 25 November 2011)

The crystal structure of the title compound, C₁₈H₂₅NO₅, is stabilized by intermolecular N—H⋯O hydrogen bonds, which form inversion dimers. The ethyl group is disordered over two positions in a 0.651 (12):0.349 (12) ratio.

Related literature

For the pharmacological activity of pyrrolidin-2-one compounds, see: Ichikawa & Kato (2001 ). For applications of related compounds, see: De Clercq (2004 ); Ge et al. (2009 , 2011 ). The synthesis of the title compound was adapted from literature procedures for the preparation of closely related compounds, see: Bishop et al. (1991 ).

Experimental

Crystal data

C₁₈H₂₅NO₅
M_r = 335.39
Triclinic, $[P \overline 1]$
a = 9.7995 (18) Å
b = 10.0340 (19) Å
c = 10.481 (2) Å
α = 100.571 (3)°
β = 105.350 (3)°
γ = 107.957 (3)°
V = 905.1 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.24 × 0.19 × 0.16 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.979, T_max = 0.986
4623 measured reflections
3167 independent reflections
2598 reflections with I > 2σ(I)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.138
S = 1.06
3167 reflections
236 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O4ⁱ	0.86	2.30	3.074 (2)	149
Symmetry code: (i) -x, -y+1, -z+1.

Data collection: SMART (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536811049440/fy2028sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811049440/fy2028Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536811049440/fy2028Isup3.cml

checkCIF report

Comment top

Synthesis of nitrogen-containing heterocyclic compounds has been a subject of great interest due to their widespread application in the agrochemical and pharmaceutical fields (Ge et al.; 2011, 2009). Some pyrrolidin-2-one derivatives which belong to this category have been of interest for their biological activities. Considerable effort has been devoted to the development of novel pyrrolidin-2-one compounds (De Clercq, 2004). We report herein the crystal structure of the title compound (Figs. 1 and 2) which is an important intermediate for the syntheses of pyrrolidin-2-ones (Fig. 3).

Related literature top

For the pharmacological activity of pyrrolidin-2-one compounds, see: Ichikawa et al. (2001). For applications of related compounds, see: De Clercq (2004); Ge et al. (2009, 2011). The synthesis of the title compound was adapted from literature procedures for the preparation of closely related compounds, see: Bishop et al. (1991).

Experimental top

The synthesis of the title compound was adapted from literature procedures for the preparation of closely related compounds (Bishop et al., 1991). A mixture of ethyl 3-oxobutanoate (0.1 mol), (chloromethyl)benzene (0.1 mol) and sodium ethanolate (0.15 mol) in ethanol (300 ml) was heated to reflux for 4 h. The product, ethyl 2-benzyl-3-oxobutanoate, was separated by column chromatography on silica gel (yield 76%). Ethyl 2-benzyl-3-oxobutanoate was reacted with HCN in ether below 15°C for 6 h. After removing the solvent, the residue was charged in a 500 ml autoclave. Then 50 g of Raney Ni and 300 ml of acetic anhydride were added to the autoclave. The mixture was reacted at 45°C under a hydrogen pressure of 2–3 MPa until the pressure reduction ceased. The Ni was removed by filtration and then the solvent was removed under reduced pressure. The final product was recrystallized from ethanol (yield 46%). Crystals of the product suitable for X-ray diffraction were obtained by slow evaporation of the solution of the product in ethanol at room temperature over 1 week.

Structure description top

Computing details top

Data collection: SMART (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level. Hydrogen atoms have been omitted for clarity.
	Fig. 2. Crystal packing of the title compound. Thin dashed lines indicate the N1—H1···O4ⁱ hydrogen bond. Symmetry code: (i) –x, –y+1, –z+1.
	Fig. 3. Reaction scheme showing the relationship of the title compound to pyrrolidin-2-ones.

Ethyl 4-acetamido-3-acetoxy-2-benzyl-3-methylbutanoate top

Crystal data top

C₁₈H₂₅NO₅	Z = 2
M_r = 335.39	F(000) = 360
Triclinic, P1	D_x = 1.231 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.7995 (18) Å	Cell parameters from 2878 reflections
b = 10.0340 (19) Å	θ = 2.6–28.3°
c = 10.481 (2) Å	µ = 0.09 mm⁻¹
α = 100.571 (3)°	T = 293 K
β = 105.350 (3)°	Block, colorless
γ = 107.957 (3)°	0.24 × 0.19 × 0.16 mm
V = 905.1 (3) Å³

Data collection top

Bruker SMART APEXII diffractometer	3167 independent reflections
Radiation source: fine-focus sealed tube	2598 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.016
φ and ω scans	θ_max = 25.1°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −10→11
T_min = 0.979, T_max = 0.986	k = −11→10
4623 measured reflections	l = −10→12

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.138	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0739P)² + 0.2116P] where P = (F_o² + 2F_c²)/3
3167 reflections	(Δ/σ)_max < 0.001
236 parameters	Δρ_max = 0.20 e Å⁻³
2 restraints	Δρ_min = −0.19 e Å⁻³

Crystal data top

C₁₈H₂₅NO₅	γ = 107.957 (3)°
M_r = 335.39	V = 905.1 (3) Å³
Triclinic, P1	Z = 2
a = 9.7995 (18) Å	Mo Kα radiation
b = 10.0340 (19) Å	µ = 0.09 mm⁻¹
c = 10.481 (2) Å	T = 293 K
α = 100.571 (3)°	0.24 × 0.19 × 0.16 mm
β = 105.350 (3)°

Data collection top

Bruker SMART APEXII diffractometer	3167 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2598 reflections with I > 2σ(I)
T_min = 0.979, T_max = 0.986	R_int = 0.016
4623 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	2 restraints
wR(F²) = 0.138	H-atom parameters constrained
S = 1.06	Δρ_max = 0.20 e Å⁻³
3167 reflections	Δρ_min = −0.19 e Å⁻³
236 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)
O1	0.14359 (19)	0.04705 (16)	0.78101 (19)	0.0813 (5)
O2	0.34401 (17)	0.22351 (16)	0.77960 (16)	0.0650 (4)
O3	0.20424 (15)	0.64375 (16)	1.02379 (13)	0.0606 (4)
O4	−0.09510 (15)	0.32515 (17)	0.46869 (13)	0.0614 (4)
O5	0.09310 (13)	0.29479 (13)	0.62267 (11)	0.0451 (3)
N1	0.12798 (17)	0.57192 (15)	0.79270 (15)	0.0456 (4)
H1	0.1480	0.5898	0.7211	0.055*
C1	0.2615 (2)	0.1673 (2)	1.1462 (2)	0.0556 (5)
H1A	0.1808	0.0775	1.1024	0.067*
C2	0.3832 (3)	0.1795 (3)	1.2567 (2)	0.0675 (6)
H2	0.3837	0.0982	1.2872	0.081*
C3	0.5025 (3)	0.3099 (3)	1.3211 (2)	0.0696 (6)
H3	0.5837	0.3183	1.3963	0.083*
C4	0.5024 (3)	0.4290 (3)	1.2746 (2)	0.0750 (7)
H4	0.5849	0.5178	1.3168	0.090*
C5	0.3802 (2)	0.4171 (2)	1.1653 (2)	0.0636 (6)
H5	0.3804	0.4988	1.1353	0.076*
C6	0.25803 (19)	0.28698 (19)	1.09999 (17)	0.0442 (4)
C7	0.1239 (2)	0.2751 (2)	0.98167 (18)	0.0494 (4)
H7A	0.0849	0.3488	1.0111	0.059*
H7B	0.0434	0.1799	0.9579	0.059*
C8	0.16401 (18)	0.29482 (18)	0.85328 (16)	0.0397 (4)
H8	0.2507	0.3879	0.8806	0.048*
C9	0.2136 (2)	0.1739 (2)	0.80042 (18)	0.0481 (4)
C10	0.4408 (12)	0.1485 (12)	0.7559 (10)	0.060 (2)	0.349 (12)
H10A	0.4094	0.0537	0.7727	0.072*	0.349 (12)
H10B	0.5466	0.2054	0.8134	0.072*	0.349 (12)
C11	0.417 (2)	0.1330 (19)	0.6029 (7)	0.106 (5)	0.349 (12)
H11A	0.4724	0.0766	0.5728	0.159*	0.349 (12)
H11B	0.4546	0.2283	0.5902	0.159*	0.349 (12)
H11C	0.3106	0.0844	0.5496	0.159*	0.349 (12)
C10'	0.3713 (8)	0.0989 (6)	0.7031 (7)	0.0680 (14)	0.651 (12)
H10C	0.2790	0.0317	0.6284	0.082*	0.651 (12)
H10D	0.4071	0.0459	0.7644	0.082*	0.651 (12)
C11'	0.4937 (6)	0.1734 (7)	0.6475 (8)	0.0788 (16)	0.651 (12)
H11D	0.5166	0.1006	0.5934	0.118*	0.651 (12)
H11E	0.5844	0.2377	0.7232	0.118*	0.651 (12)
H11F	0.4574	0.2288	0.5907	0.118*	0.651 (12)
C12	0.03185 (18)	0.29931 (18)	0.73647 (16)	0.0411 (4)
C13	−0.1161 (2)	0.1694 (2)	0.6960 (2)	0.0583 (5)
H13A	−0.1894	0.1721	0.6160	0.087*
H13B	−0.1549	0.1730	0.7711	0.087*
H13C	−0.0978	0.0805	0.6753	0.087*
C14	0.00377 (19)	0.43993 (19)	0.77358 (18)	0.0441 (4)
H14A	−0.0853	0.4337	0.7010	0.053*
H14B	−0.0202	0.4466	0.8580	0.053*
C15	0.2144 (2)	0.66885 (19)	0.91664 (18)	0.0455 (4)
C16	0.3241 (3)	0.8094 (2)	0.9149 (3)	0.0736 (6)
H16A	0.3159	0.8900	0.9735	0.110*
H16B	0.3006	0.8168	0.8221	0.110*
H16C	0.4263	0.8118	0.9478	0.110*
C17	0.0227 (2)	0.30512 (19)	0.49921 (17)	0.0458 (4)
C18	0.1100 (2)	0.2895 (2)	0.4059 (2)	0.0604 (5)
H18A	0.0421	0.2542	0.3117	0.091*
H18B	0.1576	0.2214	0.4248	0.091*
H18C	0.1871	0.3829	0.4205	0.091*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0832 (11)	0.0437 (9)	0.1075 (13)	0.0247 (8)	0.0207 (9)	0.0160 (8)
O2	0.0795 (10)	0.0686 (9)	0.0821 (10)	0.0499 (8)	0.0469 (8)	0.0361 (8)
O3	0.0617 (8)	0.0703 (9)	0.0423 (7)	0.0166 (7)	0.0156 (6)	0.0170 (6)
O4	0.0585 (8)	0.0872 (10)	0.0472 (7)	0.0395 (7)	0.0129 (6)	0.0261 (7)
O5	0.0458 (6)	0.0549 (7)	0.0351 (6)	0.0234 (5)	0.0093 (5)	0.0134 (5)
N1	0.0576 (9)	0.0473 (8)	0.0414 (8)	0.0242 (7)	0.0216 (7)	0.0202 (7)
C1	0.0547 (11)	0.0570 (11)	0.0591 (11)	0.0200 (9)	0.0188 (9)	0.0288 (9)
C2	0.0691 (13)	0.0815 (15)	0.0728 (14)	0.0394 (12)	0.0256 (11)	0.0492 (13)
C3	0.0580 (12)	0.0973 (17)	0.0556 (12)	0.0329 (12)	0.0100 (10)	0.0346 (12)
C4	0.0666 (13)	0.0727 (15)	0.0606 (13)	0.0128 (11)	−0.0015 (10)	0.0196 (11)
C5	0.0710 (13)	0.0523 (11)	0.0555 (12)	0.0195 (10)	0.0042 (10)	0.0209 (9)
C6	0.0472 (9)	0.0517 (10)	0.0408 (9)	0.0221 (8)	0.0176 (7)	0.0198 (8)
C7	0.0453 (9)	0.0615 (11)	0.0456 (10)	0.0214 (8)	0.0150 (8)	0.0239 (8)
C8	0.0369 (8)	0.0409 (9)	0.0387 (9)	0.0138 (7)	0.0082 (7)	0.0143 (7)
C9	0.0532 (10)	0.0453 (10)	0.0443 (9)	0.0222 (8)	0.0088 (8)	0.0150 (8)
C10	0.048 (5)	0.059 (5)	0.075 (5)	0.031 (4)	0.016 (4)	0.015 (4)
C11	0.114 (11)	0.117 (10)	0.075 (7)	0.068 (9)	0.013 (6)	−0.013 (6)
C10'	0.077 (4)	0.066 (3)	0.067 (3)	0.044 (3)	0.023 (3)	0.008 (2)
C11'	0.077 (3)	0.097 (4)	0.070 (4)	0.049 (3)	0.030 (3)	0.006 (3)
C12	0.0387 (8)	0.0464 (9)	0.0373 (9)	0.0158 (7)	0.0100 (7)	0.0149 (7)
C13	0.0433 (10)	0.0572 (12)	0.0586 (12)	0.0088 (8)	0.0041 (8)	0.0177 (9)
C14	0.0416 (8)	0.0548 (10)	0.0401 (9)	0.0232 (8)	0.0124 (7)	0.0167 (8)
C15	0.0493 (9)	0.0478 (10)	0.0470 (10)	0.0243 (8)	0.0195 (8)	0.0166 (8)
C16	0.0885 (16)	0.0507 (12)	0.0764 (15)	0.0144 (11)	0.0349 (13)	0.0171 (11)
C17	0.0492 (10)	0.0450 (10)	0.0377 (9)	0.0187 (8)	0.0065 (7)	0.0098 (7)
C18	0.0680 (12)	0.0773 (14)	0.0436 (10)	0.0375 (11)	0.0182 (9)	0.0189 (9)

Geometric parameters (Å, º) top

O1—C9	1.194 (2)	C8—H8	0.9800
O2—C9	1.313 (2)	C10—C11	1.531 (3)
O2—C10	1.423 (8)	C10—H10A	0.9700
O2—C10'	1.493 (5)	C10—H10B	0.9700
O3—C15	1.218 (2)	C11—H11A	0.9600
O4—C17	1.203 (2)	C11—H11B	0.9600
O5—C17	1.335 (2)	C11—H11C	0.9600
O5—C12	1.470 (2)	C10'—C11'	1.521 (3)
N1—C15	1.341 (2)	C10'—H10C	0.9700
N1—C14	1.434 (2)	C10'—H10D	0.9700
N1—H1	0.8600	C11'—H11D	0.9600
C1—C2	1.381 (3)	C11'—H11E	0.9600
C1—C6	1.381 (3)	C11'—H11F	0.9600
C1—H1A	0.9300	C12—C13	1.512 (2)
C2—C3	1.360 (3)	C12—C14	1.521 (2)
C2—H2	0.9300	C13—H13A	0.9600
C3—C4	1.371 (3)	C13—H13B	0.9600
C3—H3	0.9300	C13—H13C	0.9600
C4—C5	1.377 (3)	C14—H14A	0.9700
C4—H4	0.9300	C14—H14B	0.9700
C5—C6	1.371 (3)	C15—C16	1.493 (3)
C5—H5	0.9300	C16—H16A	0.9600
C6—C7	1.506 (2)	C16—H16B	0.9600
C7—C8	1.528 (2)	C16—H16C	0.9600
C7—H7A	0.9700	C17—C18	1.477 (3)
C7—H7B	0.9700	C18—H18A	0.9600
C8—C9	1.508 (2)	C18—H18B	0.9600
C8—C12	1.548 (2)	C18—H18C	0.9600

C9—O2—C10	128.9 (5)	H11A—C11—H11C	109.5
C9—O2—C10'	109.6 (2)	H11B—C11—H11C	109.5
C10—O2—C10'	28.2 (3)	O2—C10'—C11'	103.4 (4)
C17—O5—C12	123.96 (13)	O2—C10'—H10C	111.1
C15—N1—C14	123.26 (14)	C11'—C10'—H10C	111.1
C15—N1—H1	118.4	O2—C10'—H10D	111.1
C14—N1—H1	118.4	C11'—C10'—H10D	111.1
C2—C1—C6	120.78 (19)	H10C—C10'—H10D	109.0
C2—C1—H1A	119.6	C10'—C11'—H11D	109.5
C6—C1—H1A	119.6	C10'—C11'—H11E	109.5
C3—C2—C1	120.28 (19)	H11D—C11'—H11E	109.5
C3—C2—H2	119.9	C10'—C11'—H11F	109.5
C1—C2—H2	119.9	H11D—C11'—H11F	109.5
C2—C3—C4	119.68 (19)	H11E—C11'—H11F	109.5
C2—C3—H3	120.2	O5—C12—C13	110.07 (14)
C4—C3—H3	120.2	O5—C12—C14	110.82 (13)
C3—C4—C5	120.0 (2)	C13—C12—C14	109.41 (14)
C3—C4—H4	120.0	O5—C12—C8	101.15 (12)
C5—C4—H4	120.0	C13—C12—C8	113.50 (14)
C6—C5—C4	121.22 (19)	C14—C12—C8	111.67 (14)
C6—C5—H5	119.4	C12—C13—H13A	109.5
C4—C5—H5	119.4	C12—C13—H13B	109.5
C5—C6—C1	118.05 (17)	H13A—C13—H13B	109.5
C5—C6—C7	120.95 (16)	C12—C13—H13C	109.5
C1—C6—C7	121.00 (17)	H13A—C13—H13C	109.5
C6—C7—C8	113.01 (14)	H13B—C13—H13C	109.5
C6—C7—H7A	109.0	N1—C14—C12	115.47 (14)
C8—C7—H7A	109.0	N1—C14—H14A	108.4
C6—C7—H7B	109.0	C12—C14—H14A	108.4
C8—C7—H7B	109.0	N1—C14—H14B	108.4
H7A—C7—H7B	107.8	C12—C14—H14B	108.4
C9—C8—C7	109.42 (14)	H14A—C14—H14B	107.5
C9—C8—C12	109.97 (14)	O3—C15—N1	122.09 (16)
C7—C8—C12	113.48 (13)	O3—C15—C16	122.17 (18)
C9—C8—H8	107.9	N1—C15—C16	115.74 (17)
C7—C8—H8	107.9	C15—C16—H16A	109.5
C12—C8—H8	107.9	C15—C16—H16B	109.5
O1—C9—O2	123.37 (18)	H16A—C16—H16B	109.5
O1—C9—C8	124.07 (18)	C15—C16—H16C	109.5
O2—C9—C8	112.55 (15)	H16A—C16—H16C	109.5
O2—C10—C11	101.9 (8)	H16B—C16—H16C	109.5
O2—C10—H10A	111.4	O4—C17—O5	124.54 (17)
C11—C10—H10A	111.4	O4—C17—C18	124.82 (16)
O2—C10—H10B	111.4	O5—C17—C18	110.64 (15)
C11—C10—H10B	111.4	C17—C18—H18A	109.5
H10A—C10—H10B	109.3	C17—C18—H18B	109.5
C10—C11—H11A	109.5	H18A—C18—H18B	109.5
C10—C11—H11B	109.5	C17—C18—H18C	109.5
H11A—C11—H11B	109.5	H18A—C18—H18C	109.5
C10—C11—H11C	109.5	H18B—C18—H18C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O4ⁱ	0.86	2.30	3.074 (2)	149

Symmetry code: (i) −x, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₈H₂₅NO₅
M_r	335.39
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	9.7995 (18), 10.0340 (19), 10.481 (2)
α, β, γ (°)	100.571 (3), 105.350 (3), 107.957 (3)
V (Å³)	905.1 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.24 × 0.19 × 0.16

Data collection
Diffractometer	Bruker SMART APEXII
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.979, 0.986
No. of measured, independent and observed [I > 2σ(I)] reflections	4623, 3167, 2598
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.596

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.138, 1.06
No. of reflections	3167
No. of parameters	236
No. of restraints	2
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.19

Computer programs: SMART (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O4ⁱ	0.86	2.30	3.074 (2)	149.4

Symmetry code: (i) −x, −y+1, −z+1.

Acknowledgements

This study was supported by the Natural Science Foundation of Shandong Province (Y2007C126).

References

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