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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 10| October 2009| Page o2351
doi:10.1107/S1600536809035132

(E)-Ethyl 2-cyano-3-(3,4-dihydr­­oxy-5-nitro­phen­yl)acrylate

Shi-Jie Zhang,a Xian-Ming Zhengb and Wei-Xiao Hua*

aCollege of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, People's Republic of China, and bHisoar Pharmaceutical Co. Ltd, Taizhou 318000, Zhejiang Province, People's Republic of China
*Correspondence e-mail: huyang@mail.hz.zj.cn (W.-X. Hu)

(Received 11 August 2009; accepted 1 September 2009; online 5 September 2009)

The title compound, C12H10N2O6, was synthesized via a Knoevenagel condensation and crystallized from ethanol. In the crystal, strong classical inter­molecular O—H⋯O hydrogen bonds and weak C—H⋯N contacts link the mol­ecules into ribbons extending along [010]. Intra­molecular O—H⋯O and C—H⋯N contacts support the planar conformation of the mol­ecules (mean deivation 0.0270 Å).

Related literature

For the syntheses of some potent and selective catechol O-methyl­transferase inhibitors, see: Bäckström et al. (1989[Bäckström, R., Honkanen, E., Pippuri, A., Kairisalo, P., Pystynen, J., Heinola, K., Nissinen, E., Linden, I.-B., Männistö, P. T., Kaakkola, S. & Pohto, P. (1989). J. Med. Chem. 32, 841-846.]). For structure–activity relationships of catechol O-methyl­transferase inhibitors, see: Tervo et al. (2003[Tervo, A. J., Nyrönen, T. H., Rönkkö, T. & Poso, A. (2003). J. Comput. Aid. Mol. Des. 17, 797-810.]). For Entacapone-related crystal structures, see: Zheng et al. (2007[Zheng, X.-M., Hu, W.-X. & Xu, F. (2007). Acta Cryst. E63, o1317-o1318.]). For the synthesis and anti­cancer evaluation of E-2-cyano-(3-substituted phen­yl)acyl­amides, see: Zhou et al. (2009[Zhou, W., Li, H.-B., Xia, C.-N., Zheng, X.-M. & Hu, W.-X. (2009). Bioorg. Med. Chem. Lett. 19, 1861-1865.]).

[Scheme 1]

Experimental

Crystal data

  • C12H10N2O6

  • Mr = 278.22

  • Monoclinic, C 2/c

  • a = 24.983 (9) Å

  • b = 13.485 (5) Å

  • c = 7.312 (3) Å

  • β = 105.911 (4)°

  • V = 2369.0 (16) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.13 mm−1

  • T = 93 K

  • 0.40 × 0.20 × 0.10 mm
Data collection

  • Rigaku AFC10/Saturn724+ diffractometer

  • Absorption correction: none

  • 9288 measured reflections

  • 2714 independent reflections

  • 2134 reflections with I > 2σ(I)

  • Rint = 0.042
Refinement

  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.118

  • S = 1.00

  • 2714 reflections

  • 190 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.30 e Å−3

  • Δρmin = −0.31 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O1—H1O⋯O6i 0.91 (3) 1.76 (3) 2.6692 (18) 176 (2)
C5—H5⋯N1ii 0.95 2.57 3.467 (3) 159
O2—H2O⋯O3 0.96 (3) 1.72 (3) 2.584 (2) 149 (2)
C1—H1⋯N1 0.95 2.62 3.474 (3) 150
Symmetry codes: (i) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (ii) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: CrystalClear (Rigaku/MSC, 2008[Rigaku/MSC (2008). CrystalClear. Rigaku/MSC Inc., The Woodlands, Texas, USA.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: publCIF (Westrip, 2009[Westrip, S. P. (2009). publCIF. In preparation.]).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809035132/si2196sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809035132/si2196Isup2.hkl

checkCIF report


Comment top

Entacapone has been found to possess anticancer activity. Structure-activity relationships of entacapone revealed that catechol, cyano moieties and trans double-bond are necessary to sustain the activity and a nitro group substituted at C5 phenyl ring is preferable, and the amide group could be modified. (Bäckström et al., 1989 & Tervo et al., 2003) In continuation of our work on synthesis, crystal structure and anticancer evaluation of E-2-cyano-(3-substituted phenyl)acylamides, (Zheng et al., 2007 & Zhou et al., 2009) we synthesized E-2-cyano-substituted phenyl acrylic acid or its esters under Knoevenagel condensation, among which only E-2-cyano-3-(3,4-dihydroxyphenyl)acrylic acid had good in vitro KB inhibitory activity at IC50 36 µM. Herein, we present the structure of the title compound (I).

The molecular structure of (I) is illustrated in Fig. 1. The phenyl ring, atoms C7 > C9, O1 > O6 and N2 are almost coplanar, which makes dihedral angles of 14.2 (2)° and 8.72 (2)° with the planes C8/N10/C1 and O5/C11/C12, respectively. As shown in Fig. 2, the molecules are linked into chains along the b axis to form ribbons which are oriented parallel to the a,b plane. There are two intermolecular and two intramolecular (O—H···O and C1—H···N) hydrogen bonds (Table 1) which contribute to the formation of parallel ribbons in the crystal lattice.

Related literature top

For the syntheses of some potent and selective catechol O-methyltransferase inhibitors, see: Bäckström et al. (1989). For structure–activity relationships of catechol O-methyltransferase inhibitors, see: Tervo et al. (2003). For Entacapone-related crystal structures, see: Zheng et al. (2007). For the synthesis and anticancer evaluation of E-2-cyano-(3-substituted phenyl)acylamides, see: Zhou et al. (2009).

Experimental top

To a stirred ethanol solution, was added 3,4-dihydroxy-5-nitrobenzaldehyde (4.9 g, 27 mmol), ethyl 2-cyanoacetate (3.4 g, 30 mmol) and ammonium acetate (0.75 g, 9.7 mmol). The mixture was heated to reflux for 6 h before filtration and the solid obtained was recrystallized from ethanol to afford the title compound as yellow solid, 6.1 g (81.9%); mp: 484–485 K; IR (KBr): 3446, 3232, 2223, 1687, 1602, 1543, 1284, 1221 cm-1; 1H NMR (DMSO-d6, 400 MHz) p.p.m.: 8.29, 8.10, 7.89, 4.32–4.28, 1.31–1.28; EIMS (%): 278 (M+, 17), 250 (31), 233 (23), 202 (55), 174 (31), 158 (34), 130 (25), 102 (28). The title compound was dissolved in ethanol and the solution evaporated gradually at r.t. to give single crystals of (I).

Refinement top

H atoms of the O—H groups were located from difference Fourier maps, they were freely refined. All H atoms of parent C atoms were placed in calculated positions and treated as riding, with C—H = 0.95 Å, and their displacement parameters set to Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2008); cell refinement: CrystalClear (Rigaku/MSC, 2008); data reduction: CrystalClear (Rigaku/MSC, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures top
[Figure 1] Fig. 1. : The molecular structure of (I) shown with 50% probability displacement ellipsoids.
[Figure 2] Fig. 2. : A section of the crystal structure of (I), viewed down the c axis.
(E)-Ethyl 2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylate top
Crystal data top
C12H10N2O6F(000) = 1152
Mr = 278.22Dx = 1.560 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 3450 reflections
a = 24.983 (9) Åθ = 3.0–27.5°
b = 13.485 (5) ŵ = 0.13 mm−1
c = 7.312 (3) ÅT = 93 K
β = 105.911 (4)°Prism, yellow
V = 2369.0 (16) Å30.40 × 0.20 × 0.10 mm
Z = 8
Data collection top
Rigaku AFC10/Saturn724+
diffractometer		2134 reflections with I > 2σ(I)
Radiation source: Rotating AnodeRint = 0.042
Graphite monochromatorθmax = 27.6°, θmin = 3.0°
Detector resolution: 28.5714 pixels mm-1h = −28→32
multi–scank = −17→17
9288 measured reflectionsl = −9→6
2714 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.118H atoms treated by a mixture of independent and constrained refinement
S = 1.00 w = 1/[σ2(Fo2) + (0.0596P)2 + 0.69P]
where P = (Fo2 + 2Fc2)/3
2714 reflections(Δ/σ)max < 0.001
190 parametersΔρmax = 0.30 e Å−3
0 restraintsΔρmin = −0.31 e Å−3
Crystal data top
C12H10N2O6V = 2369.0 (16) Å3
Mr = 278.22Z = 8
Monoclinic, C2/cMo Kα radiation
a = 24.983 (9) ŵ = 0.13 mm−1
b = 13.485 (5) ÅT = 93 K
c = 7.312 (3) Å0.40 × 0.20 × 0.10 mm
β = 105.911 (4)°
Data collection top
Rigaku AFC10/Saturn724+
diffractometer		2134 reflections with I > 2σ(I)
9288 measured reflectionsRint = 0.042
2714 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.118H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.30 e Å−3
2714 reflectionsΔρmin = −0.31 e Å−3
190 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
xyzUiso*/Ueq
O10.39296 (5)0.60992 (8)0.12800 (18)0.0219 (3)
O20.45623 (5)0.47578 (9)0.04941 (17)0.0222 (3)
O30.47644 (5)0.28865 (9)0.03118 (18)0.0269 (3)
O40.41766 (5)0.17833 (9)0.07290 (19)0.0292 (3)
O50.13633 (5)0.39925 (8)0.35194 (16)0.0196 (3)
O60.17659 (5)0.25177 (9)0.32497 (17)0.0251 (3)
N10.20946 (6)0.59192 (11)0.2676 (2)0.0237 (3)
N20.43188 (6)0.26508 (11)0.0670 (2)0.0222 (3)
C10.32709 (7)0.48910 (12)0.1768 (2)0.0179 (4)
H10.30330.53910.20230.022*
C20.37531 (7)0.51576 (12)0.1344 (2)0.0174 (4)
C30.41109 (7)0.44238 (13)0.0937 (2)0.0180 (4)
C40.39609 (7)0.34321 (12)0.1026 (2)0.0178 (4)
C50.34721 (7)0.31586 (12)0.1455 (2)0.0189 (4)
H50.33790.24770.14890.023*
C60.31215 (7)0.38778 (12)0.1831 (2)0.0177 (4)
C70.26290 (7)0.35205 (12)0.2309 (2)0.0186 (4)
H70.26010.28190.23520.022*
C80.22018 (7)0.40137 (12)0.2704 (2)0.0182 (4)
C90.17571 (7)0.34244 (12)0.3181 (2)0.0188 (4)
C100.21410 (7)0.50688 (13)0.2690 (2)0.0189 (4)
C110.09158 (7)0.34963 (13)0.4102 (2)0.0216 (4)
H11A0.10720.30130.51290.026*
H11B0.06680.31380.30130.026*
C120.05971 (7)0.42919 (13)0.4796 (3)0.0248 (4)
H12A0.08400.46090.59270.030*
H12B0.02760.39950.51190.030*
H12C0.04670.47890.37950.030*
H2O0.4735 (10)0.4161 (19)0.024 (3)0.055 (7)*
H1O0.3692 (11)0.659 (2)0.139 (3)0.063 (8)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0197 (6)0.0149 (6)0.0348 (7)−0.0012 (5)0.0136 (5)0.0001 (5)
O20.0176 (6)0.0218 (7)0.0314 (7)−0.0007 (5)0.0138 (5)0.0004 (5)
O30.0211 (7)0.0268 (7)0.0379 (7)0.0035 (5)0.0169 (6)0.0005 (6)
O40.0312 (7)0.0163 (6)0.0449 (8)0.0022 (5)0.0184 (6)−0.0011 (5)
O50.0177 (6)0.0184 (6)0.0259 (6)−0.0003 (5)0.0115 (5)0.0015 (5)
O60.0243 (7)0.0172 (6)0.0395 (8)−0.0008 (5)0.0183 (6)0.0000 (5)
N10.0206 (8)0.0207 (8)0.0323 (8)0.0006 (6)0.0117 (6)0.0001 (6)
N20.0214 (8)0.0199 (7)0.0268 (8)0.0047 (6)0.0094 (6)−0.0005 (6)
C10.0162 (8)0.0175 (8)0.0215 (8)0.0014 (6)0.0076 (7)−0.0003 (6)
C20.0180 (9)0.0144 (8)0.0206 (8)0.0010 (6)0.0067 (7)0.0008 (6)
C30.0154 (8)0.0203 (8)0.0195 (8)0.0004 (6)0.0068 (7)0.0000 (6)
C40.0173 (8)0.0164 (8)0.0208 (8)0.0039 (6)0.0069 (7)−0.0003 (6)
C50.0192 (8)0.0176 (8)0.0211 (8)−0.0004 (7)0.0074 (7)−0.0004 (6)
C60.0169 (8)0.0176 (8)0.0198 (8)−0.0014 (6)0.0070 (7)−0.0004 (6)
C70.0204 (9)0.0157 (8)0.0211 (8)−0.0019 (6)0.0081 (7)0.0003 (6)
C80.0188 (8)0.0170 (8)0.0202 (8)−0.0005 (6)0.0076 (7)−0.0003 (6)
C90.0183 (9)0.0193 (8)0.0206 (8)−0.0007 (7)0.0085 (7)−0.0013 (7)
C100.0146 (8)0.0216 (9)0.0223 (8)−0.0013 (7)0.0082 (7)−0.0005 (7)
C110.0194 (9)0.0221 (9)0.0274 (9)−0.0044 (7)0.0133 (7)−0.0010 (7)
C120.0224 (10)0.0227 (9)0.0346 (10)−0.0005 (7)0.0167 (8)−0.0016 (7)
Geometric parameters (Å, º) top
O1—C21.3491 (19)C3—C41.395 (2)
O1—H1O0.90 (3)C4—C51.391 (2)
O2—C31.334 (2)C5—C61.384 (2)
O2—H2O0.95 (3)C5—H50.9500
O3—N21.2528 (19)C6—C71.450 (2)
O4—N21.2266 (19)C7—C81.354 (2)
O5—C91.322 (2)C7—H70.9500
O5—C111.463 (2)C8—C101.431 (2)
O6—C91.224 (2)C8—C91.484 (2)
N1—C101.152 (2)C11—C121.505 (2)
N2—C41.451 (2)C11—H11A0.9900
C1—C21.372 (2)C11—H11B0.9900
C1—C61.420 (2)C12—H12A0.9800
C1—H10.9500C12—H12B0.9800
C2—C31.419 (2)C12—H12C0.9800
C2—O1—H1O117.0 (17)C1—C6—C7125.12 (15)
C3—O2—H2O102.7 (15)C8—C7—C6131.17 (16)
C9—O5—C11117.16 (13)C8—C7—H7114.4
O4—N2—O3122.12 (14)C6—C7—H7114.4
O4—N2—C4119.20 (15)C7—C8—C10125.13 (15)
O3—N2—C4118.68 (14)C7—C8—C9118.16 (16)
C2—C1—C6120.95 (15)C10—C8—C9116.71 (15)
C2—C1—H1119.5O6—C9—O5125.26 (15)
C6—C1—H1119.5O6—C9—C8122.58 (15)
O1—C2—C1124.76 (15)O5—C9—C8112.16 (15)
O1—C2—C3114.74 (15)N1—C10—C8179.64 (18)
C1—C2—C3120.49 (15)O5—C11—C12106.83 (14)
O2—C3—C4126.20 (15)O5—C11—H11A110.4
O2—C3—C2116.01 (15)C12—C11—H11A110.4
C4—C3—C2117.79 (15)O5—C11—H11B110.4
C5—C4—C3121.88 (15)C12—C11—H11B110.4
C5—C4—N2118.04 (15)H11A—C11—H11B108.6
C3—C4—N2120.08 (15)C11—C12—H12A109.5
C6—C5—C4120.10 (15)C11—C12—H12B109.5
C6—C5—H5119.9H12A—C12—H12B109.5
C4—C5—H5119.9C11—C12—H12C109.5
C5—C6—C1118.76 (15)H12A—C12—H12C109.5
C5—C6—C7116.10 (15)H12B—C12—H12C109.5
C6—C1—C2—O1−179.03 (15)C4—C5—C6—C10.1 (2)
C6—C1—C2—C30.7 (2)C4—C5—C6—C7−178.53 (15)
O1—C2—C3—O2−1.9 (2)C2—C1—C6—C50.0 (2)
C1—C2—C3—O2178.35 (14)C2—C1—C6—C7178.44 (15)
O1—C2—C3—C4178.37 (14)C5—C6—C7—C8−178.25 (17)
C1—C2—C3—C4−1.4 (2)C1—C6—C7—C83.3 (3)
O2—C3—C4—C5−178.26 (15)C6—C7—C8—C101.4 (3)
C2—C3—C4—C51.4 (2)C6—C7—C8—C9−178.89 (16)
O2—C3—C4—N21.8 (3)C11—O5—C9—O62.8 (2)
C2—C3—C4—N2−178.46 (14)C11—O5—C9—C8−176.96 (13)
O4—N2—C4—C51.1 (2)C7—C8—C9—O60.8 (3)
O3—N2—C4—C5−178.91 (14)C10—C8—C9—O6−179.52 (16)
O4—N2—C4—C3−179.01 (15)C7—C8—C9—O5−179.44 (14)
O3—N2—C4—C31.0 (2)C10—C8—C9—O50.3 (2)
C3—C4—C5—C6−0.8 (2)C9—O5—C11—C12168.12 (14)
N2—C4—C5—C6179.10 (14)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1O···O6i0.91 (3)1.76 (3)2.6692 (18)176 (2)
C5—H5···N1ii0.952.573.467 (3)159
O2—H2O···O30.96 (3)1.72 (3)2.584 (2)149 (2)
C1—H1···N10.952.623.474 (3)150
Symmetry codes: (i) −x+1/2, y+1/2, −z+1/2; (ii) −x+1/2, y−1/2, −z+1/2.

Experimental details

Crystal data
Chemical formulaC12H10N2O6
Mr278.22
Crystal system, space groupMonoclinic, C2/c
Temperature (K)93
a, b, c (Å)24.983 (9), 13.485 (5), 7.312 (3)
β (°) 105.911 (4)
V (Å3)2369.0 (16)
Z8
Radiation typeMo Kα
µ (mm−1)0.13
Crystal size (mm)0.40 × 0.20 × 0.10
Data collection
DiffractometerRigaku AFC10/Saturn724+
diffractometer
Absorption correction–
No. of measured, independent and
observed [I > 2σ(I)] reflections		9288, 2714, 2134
Rint0.042
(sin θ/λ)max (Å−1)0.651
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.118, 1.00
No. of reflections2714
No. of parameters190
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.30, −0.31

Computer programs: CrystalClear (Rigaku/MSC, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009), publCIF (Westrip, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1O···O6i0.91 (3)1.76 (3)2.6692 (18)176 (2)
C5—H5···N1ii0.952.573.467 (3)159
O2—H2O···O30.96 (3)1.72 (3)2.584 (2)149 (2)
C1—H1···N10.952.623.474 (3)150
Symmetry codes: (i) −x+1/2, y+1/2, −z+1/2; (ii) −x+1/2, y−1/2, −z+1/2.
 

Acknowledgements

The authors thank Dr F. Xu (Taizhou Vocational & Technical College) and Mr G. Chen for their help.

References

First citationBäckström, R., Honkanen, E., Pippuri, A., Kairisalo, P., Pystynen, J., Heinola, K., Nissinen, E., Linden, I.-B., Männistö, P. T., Kaakkola, S. & Pohto, P. (1989). J. Med. Chem. 32, 841–846.  PubMed Web of Science Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationRigaku/MSC (2008). CrystalClear. Rigaku/MSC Inc., The Woodlands, Texas, USA.  Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationTervo, A. J., Nyrönen, T. H., Rönkkö, T. & Poso, A. (2003). J. Comput. Aid. Mol. Des. 17, 797–810.  Web of Science CrossRef CAS Google Scholar
 First citationWestrip, S. P. (2009). publCIF. In preparation.  Google Scholar
 First citationZheng, X.-M., Hu, W.-X. & Xu, F. (2007). Acta Cryst. E63, o1317–o1318.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationZhou, W., Li, H.-B., Xia, C.-N., Zheng, X.-M. & Hu, W.-X. (2009). Bioorg. Med. Chem. Lett. 19, 1861-1865.  Web of Science CSD CrossRef PubMed CAS Google Scholar

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ISSN: 2056-9890
Volume 65| Part 10| October 2009| Page o2351
doi:10.1107/S1600536809035132
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