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ISSN: 2056-9890

4-[(7-Fluoro­quinazolin-4-yl)­­oxy]aniline

aSchool of Pharmaceutical Sciences, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China, bJiangsu Provincial Institute of Materia Medica, Nanjing University of Technology, No. 26 Majia Street, Nanjing 210009, People's Republic of China, and cPRC DAYAOWAN Administration for Entry & Exit Inspection and Quarantine, Haiqingdao Foreign Area Development Zone, Dalian 116610, Liaoning Province, People's Republic of China
*Correspondence e-mail: jiajing.jj@gmail.com

(Received 18 October 2010; accepted 19 December 2010; online 24 December 2010)

In the mol­ecule of the title compound, C14H10FN3O, the bicyclic quinazoline system is effectively planar, with a mean deviation from planarity of 0.0140 (3) Å. The quinazoline heterocyclic system and the adjacent benzene ring make a dihedral angle of 85.73 (9)°. Two inter­molecular N—H⋯N hydrogen bonds contribute to the stability of the crystal structure. In addition, a weak ππ stacking inter­action [centroid–centroid distance = 3.902 (2) Å] is observed.

Related literature

For general background to quinazolines, see: Labuda et al. (2009[Labuda, J., Ovadekova, R. & Galandova, J. (2009). Mikrochim. Acta, 164, 371-377.]). Graves et al. (2002[Graves, P. R., Kwiek, J. J., Fadden, P., Ray, R., Hardeman, K., Coley, A. M., Foley, M. & Haystead, T. A. J. (2002). Mol. Pharmacol. 62, 1364-1372.]); For the preparation of the title compound, see: Zhang et al. (2010[Zhang, A. H., Yuan, S. T., Shen, Y. P., Wu, Y. D. & Ji, A. C. (2010). CN Patent Appl. CN101671301.]). For bond-length data, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C14H10FN3O

  • Mr = 255.25

  • Orthorhombic, P 21 21 21

  • a = 8.0210 (16) Å

  • b = 8.3370 (17) Å

  • c = 17.562 (4) Å

  • V = 1174.4 (4) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.11 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[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.969, Tmax = 0.990

  • 2351 measured reflections

  • 1256 independent reflections

  • 883 reflections with I > 2σ(I)

  • Rint = 0.082

  • 3 standard reflections every 200 reflections intensity decay: 1%

Refinement
  • R[F2 > 2σ(F2)] = 0.045

  • wR(F2) = 0.110

  • S = 1.02

  • 1256 reflections

  • 172 parameters

  • H-atom parameters constrained

  • Δρmax = 0.12 e Å−3

  • Δρmin = −0.15 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯N2i 0.89 2.67 3.408 (4) 142
N1—H1B⋯N3ii 0.89 2.38 3.205 (4) 154
Symmetry codes: (i) [x+{\script{1\over 2}}, -y-{\script{1\over 2}}, -z+1]; (ii) [-x+{\script{1\over 2}}, -y, z-{\script{1\over 2}}].

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994[Enraf-Nonius (1994). CAD-4 EXPRESS. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Quinazoline and its derivatives have been a research hotspot for a long time, owing to their significant role in the synthesis of some tyrosine protein kinase inhibitors and their potential anti-cancer activities (Labuda et al., 2009; Graves et al., 2002). As part of our studies into the synthesis of quinazoline derivatives, the title compound 4-[(4-benzenamine)yloxy]-7-fluoroquinazoline, which may be used as an intermediate towards some quinazoline derivatives, was synthesised. We report herein the crystal structure of the title compound.

In the molecule of the title compound, (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. The bicyclic quinazoline system is effectively planar with a mean deviation of only 0.0140 (3)Å. The dihedral angle between the benzene ring C1-C6 and the quinazoline ring system is 85.73 (9)°.

Two intermolecular N-H···N hydrogen bonds contribute to the stability of the molecular configuration and the packing of the molecules (Fig. 2 and Table 1). The crystal structure (Fig. 2) is also stabilized by a weak ππ stacking interaction with centroid–centroid separation of 3.902 (2) Å for Cg1···Cg2i , where Cg1, Cg2 are the centroids of the rings N2/C7/C14/C9/N3/C8 and C1–C6, respectively [symmetry code: (i) -1/2+x, 1/2-y, 1-z].

Related literature top

For general background to quinazolines, see: Labuda et al. (2009). Graves et al. (2002); For the preparation of the title compound, see: Zhang et al. (2010). For bond-length data, see: Allen et al. (1987).

Experimental top

The title compound was prepared by following a reported procedure (Zhang et al., 2010). 4-Chloro-7-fluoroquinazoline (10 g, 54.77 mmol) was added to a mixture of dimethylformamide (100 ml), potassium tert-butoxide (6.15 g, 54.77 mmol) and 4-aminophenol (5.98 g, 54.77 mmol), and then heated to 343 K for 8 h. After cooling to room temperature, the reaction mixture was added to water (250 ml) and ethyl acetate (250 ml). The organic phase was collected and the water phase was extracted with ethyl acetate (250 ml). All the organic phases were combined and washed with brine (2× 250 ml). The organic phase was dried with anhydrous sodium sulfate for 6 h and then distilled (b.p. 313 K at 0.1 Mpa) and recrystallized from ethyl acetate, to give a total yield of 4-[(4-benzenamine)yloxy]-7-fluoroquinazoline of 81.0 % (11.32 g, 44.35 mmol). M.p. 353-355 K. ESI-MS(m/z): 256.1[M+H]+, 278.1[M+Na]+. 1H NMR (500 MHz, DMSO-d6) δ: 8.72 (s, 1 H, 8-H), 8.40 (dd, JH-F = 6.0 Hz, J = 9.0 Hz, 1 H, 13-H), 7.7 (dd, J = 2.5 Hz, JH-F = 10.0 Hz, 1 H, 10-H), 7.61 (td, J = 2.5, 9.0 Hz, JH-F = 9.0 Hz, 1H, 12-H), 7.00 (d, J = 9.0 Hz, 1H, C1-H), 7.00 (d, J = 9.0 Hz, 1H, C5-H), 6.71 (d, J = 8.5 Hz, 1H, C2-H), 6.71 (d, J = 8.5 Hz, 1H, C4-H), 5.10(s, 2H, N1-H). 13C NMR(500 MHz, DMSO-d6) δ: 166.58 (C-7), 165.12 (d, JC-F = 251.3 Hz, C-11), 155.17 (C-8), 152.64 (d, JC-F = 13.8 Hz, C-9), 146.47 (C-6), 142.05 (C-3), 126.55 (d, JC-F = 11.3 Hz, C-13), 121.89 (C-1), 121.89 (C-5), 117.38 (d, JC-F = 25.0 Hz, C-12), 114.18 (C-2), 114.18 (C-4), 112.82 (C-14), 111.38 (d, JC-F = 21.3 Hz, C-10). IR(KBr)(cm-1): νN-H (3420.80, 3327.69), νCC-H (3077.53), νC N (1628.11), δCC-H (1609.25, 1575.87, 1509.07, 1459.02), νC-N (1286.23), νAr-O (1248.06). UV-vis: λmax(CH3OH) nm (ε): 217.5 (40174), λmax (0.1M HCl) nm (ε): 230.2 (30173), λmax(0.1M NaOH) nm (ε): 216.4 (16773).

Crystals of the title compound suitable for X-ray diffraction were grown from ethyl acetate.

Refinement top

The H atoms of the NH2 group were initially located from a Difference-Fourier map, but were then constrained to ride on their parent atom N1, with N-H = 0.89 Å, and Uiso(H) = 1.2 Ueq(N1) in the final stages of the refinement. The remaining H atoms were positioned geometrically with C-H = 0.93 and 0.98 Å for aromatic and methine H atoms, respectively, and constrained to ride on their parent atoms, with Uiso(H) = 1.2 Ueq(C). In the absence of any significant anomalous scattering, Friedel pairs were merged before the final refinement and the absolute structure was assigned arbitrarily.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); 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: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level
[Figure 2] Fig. 2. A partial packing diagram. Hydrogen bonds and weak ππ stacking interactions are shown as dashed lines.
4-[(7-Fluoroquinazolin-4-yl)oxy]aniline top
Crystal data top
C14H10FN3OF(000) = 528
Mr = 255.25Dx = 1.444 Mg m3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 25 reflections
a = 8.0210 (16) Åθ = 9.0–12.0°
b = 8.3370 (17) ŵ = 0.11 mm1
c = 17.562 (4) ÅT = 293 K
V = 1174.4 (4) Å3Block, colorless
Z = 40.30 × 0.20 × 0.10 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
883 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.082
Graphite monochromatorθmax = 25.3°, θmin = 2.3°
ω/2θ scansh = 90
Absorption correction: ψ scan
(North et al., 1968)
k = 1010
Tmin = 0.969, Tmax = 0.990l = 210
2351 measured reflections3 standard reflections every 200 reflections
1256 independent reflections intensity decay: 1%
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)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.110H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.046P)2]
where P = (Fo2 + 2Fc2)/3
1256 reflections(Δ/σ)max < 0.001
172 parametersΔρmax = 0.12 e Å3
0 restraintsΔρmin = 0.15 e Å3
Crystal data top
C14H10FN3OV = 1174.4 (4) Å3
Mr = 255.25Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 8.0210 (16) ŵ = 0.11 mm1
b = 8.3370 (17) ÅT = 293 K
c = 17.562 (4) Å0.30 × 0.20 × 0.10 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
883 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.082
Tmin = 0.969, Tmax = 0.9903 standard reflections every 200 reflections
2351 measured reflections intensity decay: 1%
1256 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.110H-atom parameters constrained
S = 1.02Δρmax = 0.12 e Å3
1256 reflectionsΔρmin = 0.15 e Å3
172 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
F10.3205 (3)0.8351 (3)0.76958 (14)0.0778 (8)
O10.4564 (4)0.2636 (3)0.54742 (14)0.0600 (8)
N10.5255 (5)0.3210 (3)0.39680 (17)0.0613 (9)
H1A0.61910.37490.40600.074*
H1B0.50500.32300.34700.074*
N20.2795 (4)0.1426 (3)0.63318 (17)0.0543 (9)
N30.1694 (4)0.2924 (4)0.73803 (17)0.0558 (9)
C10.5944 (5)0.0096 (4)0.5327 (2)0.0557 (10)
H1C0.66220.03450.57400.067*
C20.6148 (5)0.1334 (4)0.49402 (19)0.0522 (9)
H2B0.69780.20420.50930.063*
C30.5145 (5)0.1730 (4)0.43328 (19)0.0449 (9)
C40.3965 (5)0.0629 (4)0.41001 (19)0.0527 (10)
H4A0.33020.08540.36790.063*
C50.3757 (5)0.0809 (4)0.4487 (2)0.0564 (10)
H5A0.29520.15400.43290.068*
C60.4732 (5)0.1138 (4)0.50944 (18)0.0472 (9)
C70.3580 (5)0.2687 (4)0.60919 (19)0.0467 (9)
C80.1880 (5)0.1638 (5)0.6966 (2)0.0593 (11)
H8A0.12970.07390.71320.071*
C90.2538 (4)0.4244 (4)0.71251 (19)0.0444 (8)
C100.2435 (5)0.5671 (4)0.7550 (2)0.0552 (10)
H10A0.18050.57250.79940.066*
C110.3285 (6)0.6964 (4)0.7291 (2)0.0540 (10)
C120.4236 (5)0.6976 (4)0.6636 (2)0.0580 (10)
H12A0.47870.79020.64810.070*
C130.4348 (5)0.5598 (4)0.6223 (2)0.0520 (10)
H13A0.49790.55770.57790.062*
C140.3511 (4)0.4204 (4)0.64658 (18)0.0420 (8)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F10.0938 (19)0.0589 (13)0.0808 (16)0.0023 (15)0.0035 (15)0.0267 (12)
O10.0754 (19)0.0483 (14)0.0565 (14)0.0111 (16)0.0223 (15)0.0100 (12)
N10.070 (2)0.0483 (17)0.0654 (19)0.0034 (18)0.0088 (19)0.0101 (15)
N20.0546 (19)0.0488 (19)0.059 (2)0.0069 (17)0.0063 (18)0.0018 (15)
N30.062 (2)0.0521 (18)0.0539 (18)0.0034 (18)0.0099 (18)0.0034 (16)
C10.057 (2)0.061 (2)0.049 (2)0.007 (2)0.004 (2)0.0017 (19)
C20.051 (2)0.057 (2)0.049 (2)0.005 (2)0.0010 (19)0.0061 (18)
C30.048 (2)0.0434 (19)0.0432 (19)0.0021 (19)0.0097 (18)0.0039 (16)
C40.050 (2)0.059 (2)0.049 (2)0.002 (2)0.008 (2)0.0106 (19)
C50.059 (2)0.051 (2)0.059 (2)0.007 (2)0.003 (2)0.005 (2)
C60.057 (2)0.0423 (19)0.0429 (19)0.0055 (19)0.009 (2)0.0038 (17)
C70.047 (2)0.049 (2)0.0441 (19)0.002 (2)0.0011 (19)0.0011 (17)
C80.059 (2)0.055 (2)0.064 (2)0.010 (2)0.012 (2)0.009 (2)
C90.0401 (19)0.046 (2)0.0473 (19)0.0028 (18)0.0046 (18)0.0004 (18)
C100.052 (2)0.065 (2)0.048 (2)0.002 (2)0.000 (2)0.0055 (19)
C110.057 (2)0.050 (2)0.054 (2)0.001 (2)0.011 (2)0.0116 (19)
C120.058 (2)0.050 (2)0.066 (2)0.012 (2)0.004 (2)0.002 (2)
C130.057 (2)0.050 (2)0.049 (2)0.007 (2)0.0003 (19)0.0032 (18)
C140.0399 (19)0.0430 (18)0.0431 (18)0.0008 (17)0.0055 (17)0.0003 (15)
Geometric parameters (Å, º) top
F1—C111.359 (4)C4—C51.388 (4)
O1—C71.342 (4)C4—H4A0.9300
O1—C61.422 (4)C5—C61.352 (5)
N1—C31.394 (4)C5—H5A0.9300
N1—H1A0.8900C7—C141.427 (4)
N1—H1B0.8901C8—H8A0.9300
N2—C71.295 (4)C9—C141.397 (5)
N2—C81.346 (4)C9—C101.407 (5)
N3—C81.305 (5)C10—C111.354 (5)
N3—C91.368 (4)C10—H10A0.9300
C1—C61.366 (5)C11—C121.380 (5)
C1—C21.381 (5)C12—C131.362 (5)
C1—H1C0.9300C12—H12A0.9300
C2—C31.376 (5)C13—C141.408 (4)
C2—H2B0.9300C13—H13A0.9300
C3—C41.380 (5)
C7—O1—C6117.6 (3)N2—C7—O1121.5 (3)
C3—N1—H1A114.6N2—C7—C14123.4 (3)
C3—N1—H1B117.1O1—C7—C14115.0 (3)
H1A—N1—H1B109.0N3—C8—N2129.2 (4)
C7—N2—C8115.3 (3)N3—C8—H8A115.4
C8—N3—C9115.0 (3)N2—C8—H8A115.4
C6—C1—C2119.1 (4)N3—C9—C14121.9 (3)
C6—C1—H1C120.5N3—C9—C10118.5 (3)
C2—C1—H1C120.5C14—C9—C10119.6 (3)
C3—C2—C1121.3 (4)C11—C10—C9117.7 (3)
C3—C2—H2B119.4C11—C10—H10A121.2
C1—C2—H2B119.4C9—C10—H10A121.2
C2—C3—C4118.1 (3)C10—C11—F1118.5 (4)
C2—C3—N1122.2 (4)C10—C11—C12124.4 (3)
C4—C3—N1119.7 (3)F1—C11—C12117.1 (3)
C3—C4—C5120.8 (3)C13—C12—C11118.3 (3)
C3—C4—H4A119.6C13—C12—H12A120.9
C5—C4—H4A119.6C11—C12—H12A120.9
C6—C5—C4119.5 (4)C12—C13—C14120.2 (3)
C6—C5—H5A120.3C12—C13—H13A119.9
C4—C5—H5A120.3C14—C13—H13A119.9
C5—C6—C1121.2 (3)C9—C14—C13119.8 (3)
C5—C6—O1119.6 (3)C9—C14—C7115.1 (3)
C1—C6—O1119.1 (3)C13—C14—C7125.0 (3)
C6—C1—C2—C30.6 (6)C8—N3—C9—C10178.5 (4)
C1—C2—C3—C42.4 (5)N3—C9—C10—C11179.7 (3)
C1—C2—C3—N1175.6 (4)C14—C9—C10—C110.7 (5)
C2—C3—C4—C52.4 (5)C9—C10—C11—F1179.8 (4)
N1—C3—C4—C5175.6 (4)C9—C10—C11—C120.4 (6)
C3—C4—C5—C60.6 (6)C10—C11—C12—C130.6 (6)
C4—C5—C6—C11.3 (5)F1—C11—C12—C13179.5 (4)
C4—C5—C6—O1177.7 (3)C11—C12—C13—C140.2 (6)
C2—C1—C6—C51.3 (5)N3—C9—C14—C13179.5 (3)
C2—C1—C6—O1177.7 (3)C10—C9—C14—C131.5 (5)
C7—O1—C6—C595.7 (4)N3—C9—C14—C71.2 (5)
C7—O1—C6—C187.9 (4)C10—C9—C14—C7177.8 (3)
C8—N2—C7—O1178.7 (3)C12—C13—C14—C91.2 (5)
C8—N2—C7—C140.5 (5)C12—C13—C14—C7178.0 (4)
C6—O1—C7—N20.7 (5)N2—C7—C14—C90.7 (5)
C6—O1—C7—C14177.7 (3)O1—C7—C14—C9177.7 (3)
C9—N3—C8—N20.8 (6)N2—C7—C14—C13179.9 (3)
C7—N2—C8—N31.3 (6)O1—C7—C14—C131.5 (5)
C8—N3—C9—C140.5 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···N2i0.892.673.408 (4)142
N1—H1B···N3ii0.892.383.205 (4)154
Symmetry codes: (i) x+1/2, y1/2, z+1; (ii) x+1/2, y, z1/2.

Experimental details

Crystal data
Chemical formulaC14H10FN3O
Mr255.25
Crystal system, space groupOrthorhombic, P212121
Temperature (K)293
a, b, c (Å)8.0210 (16), 8.3370 (17), 17.562 (4)
V3)1174.4 (4)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.30 × 0.20 × 0.10
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.969, 0.990
No. of measured, independent and
observed [I > 2σ(I)] reflections
2351, 1256, 883
Rint0.082
(sin θ/λ)max1)0.601
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.110, 1.02
No. of reflections1256
No. of parameters172
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.12, 0.15

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···N2i0.892.673.408 (4)142
N1—H1B···N3ii0.892.383.205 (4)154
Symmetry codes: (i) x+1/2, y1/2, z+1; (ii) x+1/2, y, z1/2.
 

Acknowledgements

The authors thank the Center of Testing and Analysis, Nanjing University, for the data collection.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science
First citationEnraf–Nonius (1994). CAD-4 EXPRESS. Enraf–Nonius, Delft, The Netherlands.
First citationGraves, P. R., Kwiek, J. J., Fadden, P., Ray, R., Hardeman, K., Coley, A. M., Foley, M. & Haystead, T. A. J. (2002). Mol. Pharmacol. 62, 1364–1372.  Web of Science CrossRef PubMed CAS
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
First citationLabuda, J., Ovadekova, R. & Galandova, J. (2009). Mikrochim. Acta, 164, 371–377.  Web of Science CrossRef CAS
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals
First citationZhang, A. H., Yuan, S. T., Shen, Y. P., Wu, Y. D. & Ji, A. C. (2010). CN Patent Appl. CN101671301.

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