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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 68| Part 4| April 2012| Page o1018
doi:10.1107/S1600536812009579

3,5-Di­methyl-1-(4-nitro­phen­yl)-1H-pyrazole

Edward R. T. Tiekink,a* Solange M. S. V. Wardellb and James L. Wardellc‡

aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, bCHEMSOL, 1 Harcourt Road, Aberdeen AB15 5NY, Scotland, and cCentro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz (FIOCRUZ), Casa Amarela, Campus de Manguinhos, Av. Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil
*Correspondence e-mail: edward.tiekink@gmail.com

(Received 4 March 2012; accepted 5 March 2012; online 10 March 2012)

In the title pyrazole derivative, C11H11N3O2, the benzene ring is twisted [dihedral angle = 31.38 (12)°] with respect to the pyrazole ring (r.m.s. deviation = 0.009 Å). The nitro group is effectively coplanar with the benzene ring to which it is attached [O—N—C—C torsion angle = −6.5 (3)°]. Supra­molecular chains along the b axis are formed owing to π–π inter­actions [3.8653 (2) Å] between translationally related mol­ecules involving both the five- and six-membered rings.

Related literature

For the therapeutic importance of pyrazole compounds, see: Sil et al. (2005[Sil, D., Kumar, R., Sharon, A., Maulik, P. R. & Rama, V. J. (2005). Tetrahedron Lett. 46, 3807-3809.]); Haddad et al. (2004[Haddad, N., Salvango, A. & Busacca, C. (2004). Tetrahedron Lett. 45, 5935-5937.]). For the diverse pharmacological activities of pyrazole compounds, see: Bekhit et al. (2010[Bekhit, A. A., Hymete, A., Bekhit, A., El-D, A., Damtew, A. & Aboul-Enein, H. Y. (2010). Mini Rev. Med. Chem. 10, 1014-1033.], 2012)[Bekhit, A. A., Hymete, A., Asfaw, H., Bekhit, A. & El-D, A. (2012). Arch. Pharm. 345, 147-154.]; Higashi et al. (2006[Higashi, Y., Jitsuili, D., Chayama, K. & Yoshizumi, M. (2006). Rec. Pat. Cardiovasc. Drug Dis, 1, 85-93.]). For the synthesis, see: Butler & James (1982[Butler, R. N. & James, J. P. (1982). J. Chem. Soc. Perkin Trans I, pp. 553-555.]); Claramunt et al. (2006[Claramunt, R. M., Santa Maria, M. D., Sanz, D., Alkorta, I. & Elguero, J. (2006). Magn. Res. Chem. 44, 566-570.]). For recently reported structures, see: Wardell et al. (2012[Wardell, S. M. S. V., Howie, A. H., Tiekink, E. R. T. & Wardell, J. L. (2012). Acta Cryst. E68, o992-o993.]); Baddeley et al. (2012[Baddeley, T. C., Wardell, S. M. S. V., Tiekink, E. R. T. & Wardell, J. L. (2012). Acta Cryst. E68, o1016-o1017.]).

[Scheme 1]

Experimental

Crystal data

  • C11H11N3O2

  • Mr = 217.23

  • Orthorhombic, P c a 21

  • a = 21.3909 (13) Å

  • b = 3.8653 (2) Å

  • c = 12.4514 (8) Å

  • V = 1029.51 (11) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 120 K

  • 0.26 × 0.19 × 0.04 mm
Data collection

  • Rigaku Saturn724+ diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2007[Sheldrick, G. M. (2007). SADABS. University of Göttingen, Germany.]) Tmin = 0.598, Tmax = 1.000

  • 6055 measured reflections

  • 1202 independent reflections

  • 1148 reflections with I > 2σ(I)

  • Rint = 0.046
Refinement

  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.101

  • S = 1.09

  • 1202 reflections

  • 147 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.16 e Å−3

  • Δρmin = −0.20 e Å−3

Data collection: COLLECT (Hooft, 1998[Hooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) and COLLECT; data reduction: DENZO and COLLECT; 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 DIAMOND (Brandenburg, 2006[Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812009579/hg5187sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812009579/hg5187Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812009579/hg5187Isup3.cml

checkCIF report


Comment top

Pyrazoles are key structures in numerous compounds of therapeutic importance (Sil et al., 2005, Haddad et al., 2004). Compounds containing this ring system are known to display diverse pharmacological activities, for example as anti-malarial agents (Bekhit et al., 2012), anti-inflammatory agents (Bekhit et al., 2010), and against cardiovascular disease (Higashi et al., 2006). A general route to pyrazole derivatives involves reaction of an arylhydrazine, ArNHNH2, with a β-dicarbonyl compound, R'COCH2COY. In connection with recent structural studies (Wardell et al., 2012; Baddeley et al., 2012), we now wish to report the structure of the title compound, (I), prepared from 4-O2NC6H4NHNH2 and MeCOCH2COMe.

In (I), Fig. 1, the pyrazole ring is planar with a r.m.s. deviation for the fitted atoms of 0.009 Å. The benzene ring is twisted out of this plane forming a dihedral angle of 31.38 (12)°. The nitro group is effectively co-planar with the benzene ring to which it is connected as seen in the value of the O1—N3—C9—C8 torsion angle of -6.5 (3)°.

The most prominent intermolecular interactions in the crystal structure of (I) are of the type π–π. These form between translationally related molecules along the b axis, involving both the five- and six-membered rings, and therefore, the ring centroid separations are 3.8653 (2) Å, Fig. 2. Columns pack with no specific intermolecular interactions between them, Fig. 3.

Related literature top

For the therapeutic importance of pyrazole compounds, see: Sil et al. (2005); Haddad et al. (2004). For the diverse pharmacological activities of pyrazole compounds, see: Bekhit et al. (2010, 2012); Higashi et al. (2006). For the synthesis, see: Butler & James (1982); Claramunt et al. (2006). For recently reported structures, see: Wardell et al. (2012); Baddeley et al. (2012).

Experimental top

A solution of 4-O2NC6H4NHNH2 (2 mmol) and MeCOCH2COMe (2 mmol) in EtOH (20 ml) was refluxed for 1 h. The solution was maintained at room temperature and crystals were collected after a few days, M.pt: 373–375 K; lit. M.pt: 373–375 K (Butler & James, 1982). NMR spectra were identical with those reported (Claramunt et al., 2006). IR ν: 3300, 1608, 1597, 1570, 1518, 1504, 1414, 1334, 1301, 1273, 1176, 1110, 1934, 982, 854, 825, 801, 749, 689, 640, 502 cm-1.

Refinement top

The C-bound H atoms were geometrically placed (C—H = 0.95–0.98 Å) and refined as riding with Uiso(H) = 1.2–1.5Ueq(C). In the absence of significant anomalous scattering effects, 515 Friedel pairs were averaged in the final refinement.

Structure description top

Pyrazoles are key structures in numerous compounds of therapeutic importance (Sil et al., 2005, Haddad et al., 2004). Compounds containing this ring system are known to display diverse pharmacological activities, for example as anti-malarial agents (Bekhit et al., 2012), anti-inflammatory agents (Bekhit et al., 2010), and against cardiovascular disease (Higashi et al., 2006). A general route to pyrazole derivatives involves reaction of an arylhydrazine, ArNHNH2, with a β-dicarbonyl compound, R'COCH2COY. In connection with recent structural studies (Wardell et al., 2012; Baddeley et al., 2012), we now wish to report the structure of the title compound, (I), prepared from 4-O2NC6H4NHNH2 and MeCOCH2COMe.

In (I), Fig. 1, the pyrazole ring is planar with a r.m.s. deviation for the fitted atoms of 0.009 Å. The benzene ring is twisted out of this plane forming a dihedral angle of 31.38 (12)°. The nitro group is effectively co-planar with the benzene ring to which it is connected as seen in the value of the O1—N3—C9—C8 torsion angle of -6.5 (3)°.

The most prominent intermolecular interactions in the crystal structure of (I) are of the type π–π. These form between translationally related molecules along the b axis, involving both the five- and six-membered rings, and therefore, the ring centroid separations are 3.8653 (2) Å, Fig. 2. Columns pack with no specific intermolecular interactions between them, Fig. 3.

For the therapeutic importance of pyrazole compounds, see: Sil et al. (2005); Haddad et al. (2004). For the diverse pharmacological activities of pyrazole compounds, see: Bekhit et al. (2010, 2012); Higashi et al. (2006). For the synthesis, see: Butler & James (1982); Claramunt et al. (2006). For recently reported structures, see: Wardell et al. (2012); Baddeley et al. (2012).

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); 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 DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.
[Figure 2] Fig. 2. A view of the linear supramolecular chain in (I) sustained by π–π interactions (purple dashed lines) along the b axis.
[Figure 3] Fig. 3. A view in projection down the b axis of the packing of supramolecular chains in (I).
3,5-Dimethyl-1-(4-nitrophenyl)-1H-pyrazole top
Crystal data top
C11H11N3O2F(000) = 456
Mr = 217.23Dx = 1.402 Mg m−3
Orthorhombic, Pca21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2acCell parameters from 6528 reflections
a = 21.3909 (13) Åθ = 2.9–27.5°
b = 3.8653 (2) ŵ = 0.10 mm−1
c = 12.4514 (8) ÅT = 120 K
V = 1029.51 (11) Å3Plate, light-yellow
Z = 40.26 × 0.19 × 0.04 mm
Data collection top
Rigaku Saturn724+
diffractometer		1202 independent reflections
Radiation source: Rotating Anode1148 reflections with I > 2σ(I)
Confocal monochromatorRint = 0.046
Detector resolution: 28.5714 pixels mm-1θmax = 27.5°, θmin = 3.3°
profile data from ω–scansh = −27→25
Absorption correction: multi-scan
(SADABS; Sheldrick, 2007)		k = −4→5
Tmin = 0.598, Tmax = 1.000l = −16→10
6055 measured 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)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.101H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0563P)2 + 0.2711P]
where P = (Fo2 + 2Fc2)/3
1202 reflections(Δ/σ)max < 0.001
147 parametersΔρmax = 0.16 e Å−3
1 restraintΔρmin = −0.20 e Å−3
Crystal data top
C11H11N3O2V = 1029.51 (11) Å3
Mr = 217.23Z = 4
Orthorhombic, Pca21Mo Kα radiation
a = 21.3909 (13) ŵ = 0.10 mm−1
b = 3.8653 (2) ÅT = 120 K
c = 12.4514 (8) Å0.26 × 0.19 × 0.04 mm
Data collection top
Rigaku Saturn724+
diffractometer		1202 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2007)		1148 reflections with I > 2σ(I)
Tmin = 0.598, Tmax = 1.000Rint = 0.046
6055 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0371 restraint
wR(F2) = 0.101H-atom parameters constrained
S = 1.09Δρmax = 0.16 e Å−3
1202 reflectionsΔρmin = −0.20 e Å−3
147 parameters
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
O10.25661 (11)0.8154 (7)0.1996 (2)0.0529 (6)
O20.19518 (9)0.7062 (6)0.0666 (2)0.0479 (6)
N10.44986 (9)0.1859 (5)−0.12778 (15)0.0229 (4)
N20.50113 (9)0.0689 (5)−0.07183 (17)0.0246 (4)
N30.24680 (11)0.7002 (5)0.1097 (2)0.0348 (5)
C10.45879 (11)0.1711 (6)−0.23678 (19)0.0246 (5)
C20.54135 (11)−0.0271 (6)−0.14708 (19)0.0260 (5)
C30.51697 (11)0.0328 (6)−0.2510 (2)0.0274 (5)
H30.5371−0.0138−0.31750.033*
C40.60413 (11)−0.1723 (7)−0.1187 (2)0.0308 (5)
H4A0.6188−0.0674−0.05170.046*
H4B0.6339−0.1211−0.17650.046*
H4C0.6008−0.4234−0.10950.046*
C50.41435 (12)0.3090 (7)−0.3190 (2)0.0313 (5)
H5A0.38230.1346−0.33440.047*
H5B0.43720.3637−0.38500.047*
H5C0.39430.5191−0.29140.047*
C60.39825 (10)0.3116 (6)−0.06913 (18)0.0225 (5)
C70.40877 (11)0.4650 (6)0.03071 (18)0.0251 (5)
H70.45020.48720.05740.030*
C80.35886 (11)0.5849 (6)0.0909 (2)0.0267 (5)
H80.36540.68580.15950.032*
C90.29891 (11)0.5547 (6)0.0488 (2)0.0274 (5)
C100.28776 (11)0.4044 (6)−0.0498 (2)0.0282 (5)
H100.24630.3888−0.07690.034*
C110.33738 (11)0.2765 (6)−0.1088 (2)0.0259 (5)
H110.33020.1657−0.17580.031*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0478 (12)0.0660 (13)0.0448 (13)0.0087 (12)0.0146 (10)−0.0132 (11)
O20.0249 (9)0.0550 (13)0.0640 (14)0.0063 (9)0.0092 (9)0.0016 (11)
N10.0223 (9)0.0249 (9)0.0216 (9)−0.0003 (7)−0.0012 (7)0.0011 (7)
N20.0227 (8)0.0262 (10)0.0249 (9)0.0020 (7)−0.0012 (7)0.0005 (9)
N30.0300 (11)0.0318 (11)0.0427 (13)0.0032 (9)0.0117 (10)0.0062 (10)
C10.0273 (11)0.0239 (10)0.0225 (10)−0.0041 (9)−0.0019 (9)−0.0004 (9)
C20.0279 (11)0.0224 (10)0.0275 (11)−0.0021 (9)−0.0009 (9)−0.0003 (9)
C30.0330 (12)0.0252 (11)0.0241 (11)−0.0025 (9)0.0028 (9)−0.0035 (9)
C40.0271 (11)0.0329 (13)0.0324 (13)0.0019 (9)0.0016 (9)−0.0002 (11)
C50.0337 (12)0.0368 (14)0.0233 (10)−0.0035 (11)−0.0046 (9)0.0038 (10)
C60.0236 (10)0.0202 (10)0.0238 (11)0.0000 (7)0.0009 (8)0.0023 (9)
C70.0245 (10)0.0252 (11)0.0254 (10)0.0001 (8)−0.0016 (9)0.0033 (10)
C80.0296 (11)0.0260 (11)0.0246 (11)−0.0015 (9)0.0037 (9)0.0019 (9)
C90.0250 (11)0.0260 (11)0.0312 (12)0.0019 (9)0.0073 (9)0.0059 (10)
C100.0206 (10)0.0297 (11)0.0345 (13)−0.0020 (9)−0.0014 (9)0.0060 (10)
C110.0270 (10)0.0240 (11)0.0268 (11)−0.0025 (9)−0.0042 (9)0.0012 (9)
Geometric parameters (Å, º) top
O1—N31.222 (3)C4—H4C0.9800
O2—N31.228 (3)C5—H5A0.9800
N1—C11.372 (3)C5—H5B0.9800
N1—N21.376 (3)C5—H5C0.9800
N1—C61.410 (3)C6—C71.396 (3)
N2—C21.325 (3)C6—C111.399 (3)
N3—C91.461 (3)C7—C81.384 (3)
C1—C31.366 (3)C7—H70.9500
C1—C51.495 (3)C8—C91.390 (3)
C2—C31.414 (3)C8—H80.9500
C2—C41.498 (3)C9—C101.379 (4)
C3—H30.9500C10—C111.382 (3)
C4—H4A0.9800C10—H100.9500
C4—H4B0.9800C11—H110.9500
C1—N1—N2112.11 (19)C1—C5—H5B109.5
C1—N1—C6129.48 (19)H5A—C5—H5B109.5
N2—N1—C6118.37 (19)C1—C5—H5C109.5
C2—N2—N1104.56 (19)H5A—C5—H5C109.5
O1—N3—O2123.2 (2)H5B—C5—H5C109.5
O1—N3—C9119.0 (2)C7—C6—C11120.4 (2)
O2—N3—C9117.8 (2)C7—C6—N1118.8 (2)
C3—C1—N1105.7 (2)C11—C6—N1120.8 (2)
C3—C1—C5129.1 (2)C8—C7—C6120.0 (2)
N1—C1—C5125.0 (2)C8—C7—H7120.0
N2—C2—C3111.2 (2)C6—C7—H7120.0
N2—C2—C4121.4 (2)C7—C8—C9118.6 (2)
C3—C2—C4127.4 (2)C7—C8—H8120.7
C1—C3—C2106.4 (2)C9—C8—H8120.7
C1—C3—H3126.8C10—C9—C8122.1 (2)
C2—C3—H3126.8C10—C9—N3119.5 (2)
C2—C4—H4A109.5C8—C9—N3118.4 (2)
C2—C4—H4B109.5C9—C10—C11119.4 (2)
H4A—C4—H4B109.5C9—C10—H10120.3
C2—C4—H4C109.5C11—C10—H10120.3
H4A—C4—H4C109.5C10—C11—C6119.5 (2)
H4B—C4—H4C109.5C10—C11—H11120.3
C1—C5—H5A109.5C6—C11—H11120.3
C1—N1—N2—C2−1.6 (2)N2—N1—C6—C11−148.7 (2)
C6—N1—N2—C2−179.38 (19)C11—C6—C7—C8−0.3 (3)
N2—N1—C1—C31.4 (3)N1—C6—C7—C8−178.8 (2)
C6—N1—C1—C3178.9 (2)C6—C7—C8—C9−1.2 (3)
N2—N1—C1—C5−174.1 (2)C7—C8—C9—C101.1 (4)
C6—N1—C1—C53.4 (4)C7—C8—C9—N3−176.4 (2)
N1—N2—C2—C31.1 (2)O1—N3—C9—C10176.0 (2)
N1—N2—C2—C4−179.9 (2)O2—N3—C9—C10−5.4 (3)
N1—C1—C3—C2−0.7 (3)O1—N3—C9—C8−6.5 (3)
C5—C1—C3—C2174.6 (2)O2—N3—C9—C8172.1 (2)
N2—C2—C3—C1−0.3 (3)C8—C9—C10—C110.5 (4)
C4—C2—C3—C1−179.2 (2)N3—C9—C10—C11178.0 (2)
C1—N1—C6—C7−147.5 (2)C9—C10—C11—C6−2.0 (3)
N2—N1—C6—C729.9 (3)C7—C6—C11—C101.9 (3)
C1—N1—C6—C1134.0 (3)N1—C6—C11—C10−179.6 (2)

Experimental details

Crystal data
Chemical formulaC11H11N3O2
Mr217.23
Crystal system, space groupOrthorhombic, Pca21
Temperature (K)120
a, b, c (Å)21.3909 (13), 3.8653 (2), 12.4514 (8)
V (Å3)1029.51 (11)
Z4
Radiation typeMo Kα
µ (mm−1)0.10
Crystal size (mm)0.26 × 0.19 × 0.04
Data collection
DiffractometerRigaku Saturn724+
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2007)
Tmin, Tmax0.598, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections		6055, 1202, 1148
Rint0.046
(sin θ/λ)max (Å−1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.101, 1.09
No. of reflections1202
No. of parameters147
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.16, −0.20

Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

 

Footnotes

‡Additional correspondence author, e-mail: j.wardell@abdn.ac.uk.

Acknowledgements

The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil). Support from the Ministry of Higher Education, Malaysia, High-Impact Research scheme (UM.C/HIR/MOHE/SC/12) is gratefully acknowledged.

References

First citationBaddeley, T. C., Wardell, S. M. S. V., Tiekink, E. R. T. & Wardell, J. L. (2012). Acta Cryst. E68, o1016–o1017.  CSD CrossRef IUCr Journals Google Scholar
 First citationBekhit, A. A., Hymete, A., Asfaw, H., Bekhit, A. & El-D, A. (2012). Arch. Pharm. 345, 147–154.  Web of Science CrossRef CAS Google Scholar
 First citationBekhit, A. A., Hymete, A., Bekhit, A., El-D, A., Damtew, A. & Aboul-Enein, H. Y. (2010). Mini Rev. Med. Chem. 10, 1014–1033.  Web of Science CAS PubMed Google Scholar
 First citationBrandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
 First citationButler, R. N. & James, J. P. (1982). J. Chem. Soc. Perkin Trans I, pp. 553–555.  CrossRef Web of Science Google Scholar
 First citationClaramunt, R. M., Santa Maria, M. D., Sanz, D., Alkorta, I. & Elguero, J. (2006). Magn. Res. Chem. 44, 566–570.  Web of Science CrossRef CAS Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationHaddad, N., Salvango, A. & Busacca, C. (2004). Tetrahedron Lett. 45, 5935–5937.  Web of Science CrossRef CAS Google Scholar
 First citationHigashi, Y., Jitsuili, D., Chayama, K. & Yoshizumi, M. (2006). Rec. Pat. Cardiovasc. Drug Dis, 1, 85–93.  CrossRef CAS Google Scholar
 First citationHooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
 First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
 First citationSheldrick, G. M. (2007). SADABS. University of Göttingen, Germany.  Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSil, D., Kumar, R., Sharon, A., Maulik, P. R. & Rama, V. J. (2005). Tetrahedron Lett. 46, 3807–3809.  Web of Science CSD CrossRef CAS Google Scholar
 First citationWardell, S. M. S. V., Howie, A. H., Tiekink, E. R. T. & Wardell, J. L. (2012). Acta Cryst. E68, o992–o993.  CSD CrossRef IUCr Journals Google Scholar
 First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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ISSN: 2056-9890
Volume 68| Part 4| April 2012| Page o1018
doi:10.1107/S1600536812009579
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