Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Previous article
Next article
Previous article
Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Next article

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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 4| April 2008| Page o736
doi:10.1107/S1600536808007125

Ethyl 2-(5-phenyl-1,3,4-oxa­diazol-2-ylsulfan­yl)acetate

Muhammad Zareef,a* Rashid Iqbal,a Muhammad Arfana and Masood Parvezb

aDepartment of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan, and bDepartment of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
*Correspondence e-mail: mzareef71@yahoo.com

(Received 7 March 2008; accepted 14 March 2008; online 20 March 2008)

The title mol­ecule, C12H12N2O3S, is composed of two individually planar units, viz. 5-phenyl-1,3,4-oxadiazol-2-yl-sulfanyl and ethyl acetate, which are oriented at almost right angles [80.07 (8)°] with respect to each other. The structure is stabilized by weak inter­molecular C—H⋯O and C—H⋯N hydrogen bonds. The phenyl and oxadiazole rings show π–π stacking inter­actions [centroid–centroid distance = 3.846 (2) Å] and there is also a short π-inter­action between the carbonyl O atom and the oxadiazole ring [the distance from this O atom to the centroid of the oxadiazole ring is 3.156 (2) Å].

Related literature

For related literature, see: Cao et al. (2002[Cao, S., Qian, X., Song, G. & Huang, Q. C. (2002). J. Fluorine Chem. 117, 63-66.]); Iqbal et al. (2007[Iqbal, R., Aziz, S., Ahmed, M. N., Qadeer, G. & Wong, W.-Y. (2007). Acta Cryst. E63, o1021-o1022.]); Kadi et al. (2007[Kadi, A. A., El-Brollosy, N. R., Al-Deeb, O. A., Habib, E. E., Ibrahim, T. M. & El-Emam, A. A. (2007). Eur. J. Med. Chem. 42, 235-242.]); Mir & Siddiqui (1970[Mir, I. & Siddiqui, M. T. (1970). Tetrahedron, 26, 5235-5238.]); Zareef et al. (2006[Zareef, M., Innocenti, A., Iqbal, R., Zaidi, J. H., Arfan, M., Scozzafava, A. & Supuran, C. T. J. (2006). Enzym. Inhib. Med. Chem. 21, 351-359.], 2007[Zareef, M., Iqbal, R., Al-Masoudi, N. A., Zaidi, J. H., Arfan, M. & Shahzad, S. A. (2007). Phosphorus Sulfur Silicon Relat. Elem. 182, 281-298.]).

[Scheme 1]

Experimental

Crystal data

  • C12H12N2O3S

  • Mr = 264.30

  • Monoclinic, P 21 /c

  • a = 8.777 (3) Å

  • b = 11.008 (5) Å

  • c = 13.177 (6) Å

  • β = 103.59 (3)°

  • V = 1237.5 (9) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.26 mm−1

  • T = 173 (2) K

  • 0.16 × 0.10 × 0.08 mm
Data collection

  • Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (SORTAV; Blessing, 1997[Blessing, R. H. (1997). J. Appl. Cryst. 30, 421-426.]) Tmin = 0.959, Tmax = 0.979

  • 5263 measured reflections

  • 2820 independent reflections

  • 1943 reflections with I > 2σ(I)

  • Rint = 0.046
Refinement

  • R[F2 > 2σ(F2)] = 0.045

  • wR(F2) = 0.117

  • S = 1.02

  • 2820 reflections

  • 165 parameters

  • H-atom parameters constrained

  • Δρmax = 0.25 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C4—H4⋯O2i 0.95 2.51 3.268 (3) 137
C9—H9B⋯N1ii 0.99 2.38 3.293 (3) 153
Symmetry codes: (i) -x+1, -y, -z+1; (ii) [-x+2, y+{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: COLLECT (Hooft, 1998[Hooft, R. (1998). COLLECT. Nonius B V, 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. and R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr. and R. M. Sweet, pp. 307-326. New York: Academic Press.]); program(s) used to solve structure: SAPI91 (Fan, 1991[Fan, H.-F. (1991). SAPI91. Rigaku Corporation, Tokyo, Japan.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808007125/fb2092sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808007125/fb2092Isup2.hkl

checkCIF report


Comment top

Substituted-1,3,4-oxadiazole derivatives are of significant interest due to their chemotherapeutic effects (Kadi et al., 2007; Zareef et al., 2006; Zareef et al., 2007; Cao et al., 2002). Based on the known structures of the 2,5-disubstituted-1,3,4-oxadiazoles with diverse biological activities and their derivatives, we have designed and synthesized several new derivatives of 1,3,4-oxadiazole (Zareef et al., 2007). In this paper, we report the structure of one of these compounds.

The structure of the title compound (Fig. 1) is composed of two essentially planar moieties, C1—C8/N1/N2/O1/S1 and C9—C12/O2/O3 the least-square planes of which are inclined at 80.07 (8)°; the maximum deviations from the respective least square planes are: O1 = 0.037 (2) and C11 = 0.048 (2) Å. The structure is stabilized by two intermolecular interactions C4—H4···O2 and C9—H9B···N1 (Table 1). The shortest distance between the centroids of the phenyl and the oxadiazole rings of the adjacent molecules is 3.846 (2) Å which indicates the existence of π-π stacking interactions. In addition, there is a π-interaction between the carbonyl O-atom and the oxadiazole ring. (The distance from this O atom to the centroid of the oxadiazole ring is 3.156 (2) Å). The bond distances and angles in the title compound are in agreement with the corresponding ones reported in the similar structure of Ethyl 2-({5-[2-(benzoylamino)phenyl]-1,3,4-oxadiazol-2-yl}sulfanyl)acetate (Iqbal et al., 2007).

Related literature top

For related literature, see: Cao et al. (2002); Iqbal et al. (2007); Kadi et al. (2007); Mir & Siddiqui (1970); Zareef et al. (2006, 2007).

Experimental top

The title compound was prepared according to the procedure reported in the literature (Zareef et al., 2006; Mir & Siddiqui, 1970). To a solution of benzoic acid hydrazide (50 mmol) in ethanol (150 ml) was added carbon disulfide (55 mmol), followed by the addition of KOH (50 mmol) dissolved in 25 ml of water. The reaction mixture was stirred and subjected to reflux for 19 h. After reaction completion, excess ethanol was distilled off. The crude solid obtained was dissolved in water (50 ml) and acidified with 4 N HCl to pH 2–3. The product was filtered, washed with water and recrystallized from aqueous ethanol (20–30%). The resulting 5-phenyl-2-mercapto-1,3,4-oxadiazole (20 mmol) was dissolved in saturated aqueous sodium hydrogencarbonate solution while stirring. The required ethylbromoacetate (20 mmol) in absolute ethanol (10 ml) was added and the reaction mixture was stirred for 7 h at 325–335 K. After reaction completion, the resulting solid was filtered off, washed with water and recrystallized from aqueous ethanol (60%) (Yield = 75%; m.p. = 344–345 K). Prismatic crystals suitable for crystallographic study were grown from ethanol solution by slow evaporation at room temperature.

Refinement top

Though all the H atoms could be distinguished in the difference Fouries map the H-atoms were situated at the geometrically idealized positions and refined in riding-model approximation with the following constraints: aryl, methylene and methyl C—H distances were set to 0.95, 0.99 and 0.98 Å, respectively; in all these instances Uiso(H) = 1.2 Ueq(C).

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SAPI91 (Fan, 1991); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. ORTEP-3 (Farrugia, 1997) drawing of the title molecule with displacement ellipsoids plotted at 50% probability level.
Ethyl 2-(5-phenyl-1,3,4-oxadiazol-2-ylsulfanyl)acetate top
Crystal data top
C12H12N2O3SF(000) = 552
Mr = 264.30Dx = 1.419 Mg m−3
Monoclinic, P21/cMelting point = 344–345 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 8.777 (3) ÅCell parameters from 5263 reflections
b = 11.008 (5) Åθ = 3.7–27.5°
c = 13.177 (6) ŵ = 0.26 mm−1
β = 103.59 (3)°T = 173 K
V = 1237.5 (9) Å3Prism, colourless
Z = 40.16 × 0.10 × 0.08 mm
Data collection top
Nonius KappaCCD
diffractometer		2820 independent reflections
Radiation source: fine-focus sealed tube1943 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
ω and ϕ scansθmax = 27.5°, θmin = 3.7°
Absorption correction: multi-scan
(SORTAV; Blessing, 1997)		h = −11→11
Tmin = 0.959, Tmax = 0.979k = −13→14
5263 measured reflectionsl = −17→17
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.045H-atom parameters constrained
wR(F2) = 0.117 w = 1/[σ2(Fo2) + (0.058P)2 + 0.1P]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max = 0.001
2820 reflectionsΔρmax = 0.25 e Å−3
165 parametersΔρmin = −0.27 e Å−3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
47 constraintsExtinction coefficient: 0.021 (3)
Primary atom site location: structure-invariant direct methods
Crystal data top
C12H12N2O3SV = 1237.5 (9) Å3
Mr = 264.30Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.777 (3) ŵ = 0.26 mm−1
b = 11.008 (5) ÅT = 173 K
c = 13.177 (6) Å0.16 × 0.10 × 0.08 mm
β = 103.59 (3)°
Data collection top
Nonius KappaCCD
diffractometer		2820 independent reflections
Absorption correction: multi-scan
(SORTAV; Blessing, 1997)		1943 reflections with I > 2σ(I)
Tmin = 0.959, Tmax = 0.979Rint = 0.046
5263 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.117H-atom parameters constrained
S = 1.02Δρmax = 0.25 e Å−3
2820 reflectionsΔρmin = −0.27 e Å−3
165 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
S10.76489 (6)0.36024 (5)0.69782 (4)0.0336 (2)
O10.67313 (14)0.20172 (11)0.54296 (10)0.0264 (3)
O20.86894 (16)0.19182 (14)0.88791 (12)0.0412 (4)
O31.12555 (15)0.22664 (13)0.90282 (11)0.0354 (4)
N10.87361 (18)0.07562 (15)0.55872 (13)0.0307 (4)
N20.91309 (18)0.16477 (15)0.63754 (13)0.0319 (4)
C10.6404 (2)0.03494 (16)0.41660 (14)0.0245 (4)
C20.7088 (2)−0.06503 (17)0.37915 (15)0.0283 (5)
H20.8131−0.08820.41160.034*
C30.6246 (2)−0.13002 (18)0.29499 (16)0.0339 (5)
H30.6717−0.19720.26900.041*
C40.4712 (2)−0.09762 (19)0.24806 (16)0.0335 (5)
H40.4130−0.14290.19050.040*
C50.4040 (2)0.0005 (2)0.28557 (16)0.0342 (5)
H50.29910.02250.25340.041*
C60.4870 (2)0.06791 (19)0.36949 (15)0.0291 (5)
H60.43970.13570.39450.035*
C70.7333 (2)0.10069 (16)0.50595 (15)0.0245 (4)
C80.7925 (2)0.23515 (17)0.62486 (15)0.0266 (4)
C90.9529 (2)0.35400 (18)0.78938 (17)0.0337 (5)
H9A1.03580.34990.74980.040*
H9B0.96840.43020.83040.040*
C100.9730 (2)0.24772 (19)0.86414 (16)0.0311 (5)
C111.1623 (2)0.1290 (2)0.97896 (17)0.0392 (6)
H11A1.11050.05280.94920.047*
H11B1.12520.14981.04220.047*
C121.3366 (2)0.1135 (2)1.00597 (17)0.0421 (6)
H12A1.36550.04661.05580.051*
H12B1.38640.18871.03730.051*
H12C1.37220.09520.94250.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0300 (3)0.0316 (3)0.0369 (3)0.0048 (2)0.0031 (2)−0.0069 (2)
O10.0232 (7)0.0275 (7)0.0273 (7)0.0048 (6)0.0037 (5)−0.0008 (6)
O20.0280 (7)0.0554 (10)0.0392 (9)−0.0054 (7)0.0056 (7)−0.0009 (8)
O30.0235 (7)0.0397 (8)0.0407 (9)0.0003 (6)0.0026 (6)0.0013 (7)
N10.0292 (8)0.0333 (10)0.0278 (9)0.0061 (7)0.0031 (7)−0.0055 (8)
N20.0279 (9)0.0354 (10)0.0308 (10)0.0070 (8)0.0038 (7)−0.0050 (8)
C10.0265 (9)0.0261 (10)0.0219 (10)−0.0015 (8)0.0074 (8)0.0045 (8)
C20.0275 (10)0.0286 (10)0.0288 (11)0.0000 (9)0.0066 (8)0.0020 (9)
C30.0403 (12)0.0296 (11)0.0327 (12)−0.0022 (10)0.0103 (9)−0.0023 (9)
C40.0349 (11)0.0373 (12)0.0278 (11)−0.0128 (10)0.0061 (9)−0.0010 (9)
C50.0250 (10)0.0473 (13)0.0286 (11)−0.0036 (10)0.0031 (9)0.0057 (10)
C60.0265 (10)0.0354 (11)0.0264 (11)0.0028 (9)0.0085 (8)0.0044 (9)
C70.0241 (9)0.0235 (10)0.0278 (10)0.0056 (8)0.0101 (8)0.0034 (8)
C80.0243 (9)0.0283 (10)0.0267 (10)0.0011 (9)0.0050 (8)0.0005 (8)
C90.0269 (10)0.0336 (11)0.0382 (12)−0.0033 (9)0.0027 (9)−0.0088 (9)
C100.0241 (10)0.0381 (12)0.0300 (11)−0.0027 (9)0.0040 (8)−0.0111 (9)
C110.0353 (11)0.0437 (14)0.0387 (13)0.0012 (10)0.0089 (10)0.0031 (10)
C120.0356 (12)0.0534 (15)0.0360 (13)0.0066 (11)0.0056 (10)0.0033 (11)
Geometric parameters (Å, º) top
S1—C81.729 (2)C3—H30.9500
S1—C91.802 (2)C4—C51.377 (3)
O1—C81.366 (2)C4—H40.9500
O1—C71.369 (2)C5—C61.387 (3)
O2—C101.202 (2)C5—H50.9500
O3—C101.336 (2)C6—H60.9500
O3—C111.454 (3)C9—C101.513 (3)
N1—C71.294 (2)C9—H9A0.9900
N1—N21.412 (2)C9—H9B0.9900
N2—C81.291 (2)C11—C121.497 (3)
C1—C61.392 (2)C11—H11A0.9900
C1—C21.398 (3)C11—H11B0.9900
C1—C71.457 (3)C12—H12A0.9800
C2—C31.379 (3)C12—H12B0.9800
C2—H20.9500C12—H12C0.9800
C3—C41.390 (3)
C8—S1—C996.66 (9)O1—C7—C1120.13 (15)
C8—O1—C7102.24 (13)N2—C8—O1113.20 (17)
C10—O3—C11115.56 (16)N2—C8—S1128.61 (15)
C7—N1—N2106.58 (15)O1—C8—S1118.18 (13)
C8—N2—N1105.66 (15)C10—C9—S1114.43 (14)
C6—C1—C2119.91 (17)C10—C9—H9A108.7
C6—C1—C7121.99 (18)S1—C9—H9A108.7
C2—C1—C7118.10 (16)C10—C9—H9B108.7
C3—C2—C1119.90 (18)S1—C9—H9B108.7
C3—C2—H2120.0H9A—C9—H9B107.6
C1—C2—H2120.0O2—C10—O3124.49 (19)
C2—C3—C4120.3 (2)O2—C10—C9125.87 (18)
C2—C3—H3119.8O3—C10—C9109.62 (17)
C4—C3—H3119.8O3—C11—C12107.26 (18)
C5—C4—C3119.56 (18)O3—C11—H11A110.3
C5—C4—H4120.2C12—C11—H11A110.3
C3—C4—H4120.2O3—C11—H11B110.3
C4—C5—C6121.14 (18)C12—C11—H11B110.3
C4—C5—H5119.4H11A—C11—H11B108.5
C6—C5—H5119.4C11—C12—H12A109.5
C5—C6—C1119.2 (2)C11—C12—H12B109.5
C5—C6—H6120.4H12A—C12—H12B109.5
C1—C6—H6120.4C11—C12—H12C109.5
N1—C7—O1112.32 (16)H12A—C12—H12C109.5
N1—C7—C1127.55 (18)H12B—C12—H12C109.5
C7—N1—N2—C80.1 (2)C6—C1—C7—O1−3.2 (3)
C6—C1—C2—C30.6 (3)C2—C1—C7—O1177.68 (16)
C7—C1—C2—C3179.73 (18)N1—N2—C8—O1−0.3 (2)
C1—C2—C3—C4−0.9 (3)N1—N2—C8—S1178.66 (15)
C2—C3—C4—C50.5 (3)C7—O1—C8—N20.4 (2)
C3—C4—C5—C60.1 (3)C7—O1—C8—S1−178.68 (14)
C4—C5—C6—C1−0.3 (3)C9—S1—C8—N20.1 (2)
C2—C1—C6—C50.0 (3)C9—S1—C8—O1179.01 (15)
C7—C1—C6—C5−179.09 (18)C8—S1—C9—C10−69.82 (17)
N2—N1—C7—O10.2 (2)C11—O3—C10—O2−0.3 (3)
N2—N1—C7—C1−179.84 (18)C11—O3—C10—C9177.96 (16)
C8—O1—C7—N1−0.4 (2)S1—C9—C10—O2−22.7 (3)
C8—O1—C7—C1179.66 (16)S1—C9—C10—O3159.06 (14)
C6—C1—C7—N1176.80 (19)C10—O3—C11—C12175.61 (18)
C2—C1—C7—N1−2.3 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···O2i0.952.513.268 (3)137
C9—H9B···N1ii0.992.383.293 (3)153
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+2, y+1/2, −z+3/2.

Experimental details

Crystal data
Chemical formulaC12H12N2O3S
Mr264.30
Crystal system, space groupMonoclinic, P21/c
Temperature (K)173
a, b, c (Å)8.777 (3), 11.008 (5), 13.177 (6)
β (°) 103.59 (3)
V (Å3)1237.5 (9)
Z4
Radiation typeMo Kα
µ (mm−1)0.26
Crystal size (mm)0.16 × 0.10 × 0.08
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(SORTAV; Blessing, 1997)
Tmin, Tmax0.959, 0.979
No. of measured, independent and
observed [I > 2σ(I)] reflections		5263, 2820, 1943
Rint0.046
(sin θ/λ)max (Å−1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.117, 1.02
No. of reflections2820
No. of parameters165
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.25, −0.27

Computer programs: COLLECT (Hooft, 1998), DENZO (Otwinowski & Minor, 1997), SCALEPACK (Otwinowski & Minor, 1997), SAPI91 (Fan, 1991), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···O2i0.952.513.268 (3)137
C9—H9B···N1ii0.992.383.293 (3)153
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+2, y+1/2, −z+3/2.
 

References

First citationBlessing, R. H. (1997). J. Appl. Cryst. 30, 421–426.  CrossRef CAS Web of Science IUCr Journals Google Scholar
 First citationCao, S., Qian, X., Song, G. & Huang, Q. C. (2002). J. Fluorine Chem. 117, 63–66.  Web of Science CrossRef CAS Google Scholar
 First citationFan, H.-F. (1991). SAPI91. Rigaku Corporation, Tokyo, Japan.  Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationHooft, R. (1998). COLLECT. Nonius B V, Delft, The Netherlands.  Google Scholar
 First citationIqbal, R., Aziz, S., Ahmed, M. N., Qadeer, G. & Wong, W.-Y. (2007). Acta Cryst. E63, o1021–o1022.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationKadi, A. A., El-Brollosy, N. R., Al-Deeb, O. A., Habib, E. E., Ibrahim, T. M. & El-Emam, A. A. (2007). Eur. J. Med. Chem. 42, 235–242.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationMir, I. & Siddiqui, M. T. (1970). Tetrahedron, 26, 5235–5238.  CrossRef CAS PubMed Google Scholar
 First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr. and R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationZareef, M., Innocenti, A., Iqbal, R., Zaidi, J. H., Arfan, M., Scozzafava, A. & Supuran, C. T. J. (2006). Enzym. Inhib. Med. Chem. 21, 351–359.  Web of Science CrossRef CAS Google Scholar
 First citationZareef, M., Iqbal, R., Al-Masoudi, N. A., Zaidi, J. H., Arfan, M. & Shahzad, S. A. (2007). Phosphorus Sulfur Silicon Relat. Elem. 182, 281–298.  Web of Science CrossRef CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 4| April 2008| Page o736
doi:10.1107/S1600536808007125
Follow Acta Cryst. E
Sign up for e-alerts
E-alerts
Follow Acta Cryst. on Twitter
Twitter
Follow us on facebook
Facebook
Sign up for RSS feeds
RSS