organic compounds
a]pyridine-3-carbaldehyde
of 2-(4-methoxyphenyl)-6-nitroimidazo[1,2-aLaboratoire de Chimie Appliquée et Environnement (LCAE), Faculté des Sciences, Université Mohammed Premier, BP 524, 60000-Oujda, Morocco, bObservatoire de la Lagune Marchica de Nador et Région Limitrophe, Université Mohammed Premier, Faculté Pluridisciplinaire de Nador, BP 300, Selouane 62702 Nador, Morocco, and cLaboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Université Mohammed V, Avenue Ibn Battouta, BP 1014, Rabat, Morocco
*Correspondence e-mail: a_elaatiaoui@yahoo.fr
In the title compound, C15H11N3O4, the imidazo[1,2-a] pyridine ring system is almost planar [r.m.s. deviation = 0.028 (2) Å]. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the methoxyphenyl ring and the nitro group, respectively. The cohesion of the is ensured by C—H⋯N and C—H⋯O hydrogen bonds, forming layers almost parallel to the ac plane.
Keywords: crystal structure; imidazo[1,2-a]pyridine; carbaldehyde; hydrogen bonding.
CCDC reference: 1437519
1. Related literature
For biological activities of derivatives of the title compound, see: Rupert et al. (2003); Hranjec et al. (2007); Hamdouchi et al. (1999); Rival et al. (1992); Scribner et al. (2008); Bode et al. (2011). For the synthesis of similar compounds, see: Sumalatha et al. (2009); Elaatiaoui et al. (2014, 2015).
2. Experimental
2.1. Crystal data
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2.3. Refinement
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).
Supporting information
CCDC reference: 1437519
https://doi.org/10.1107/S2056989015021957/su5244sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015021957/su5244Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989015021957/su5244Isup3.cml
Imidazo[1,2-a]pyridines are a very interesting class of α-halo ketone (Sumalatha et al., 2009). The present paper is a continuation of our research devoted to the development of imidazo[1,2-a]pyridines derivatives with potential pharmacological activities (Elaatiaoui et al., 2014;2015).
because of their wide use in medicinal chemistry for the production of various pharmacologically active agents. In addition, various derivatives of imidazo[1,2-a]pyridine show a wide range of biological activities such as anti-inflammatory (Rupert et al., 2003), antitumor (Hranjec et al., 2007), antiviral (Hamdouchi et al., 1999), antibacterial (Rival et al., 1992), antiparasitic (Scribner et al., 2008) and anti-HIV (Bode et al., 2011). The access to the imidazo[1,2-a]pyridine scaffold is generally made by condensation of 2-aminopyridine with a specifically chosenIn the title compound, Fig. 1, the fused five- and six-membered rings of the imidazo[1,2-a]pyridine moiety are virtually coplanar, with a maximum deviation of 0.028 (2) Å for atom C3. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the methoxyphenyl ring and the nitro group, respectively.
In the crystal, molecules are linked by C4–H4···N3, C15–H15A···O3 and C14–H14···O1 hydrogen bonds (Table 1), building layers parallel to (101), as shown in Fig. 2.
Phosphorus oxychloride (3.06 g, 0.02 mol) was added to a solution of 2-(4-methoxyphenyl)-5-nitroimidazo[1,2-a]pyridine (2.69 g, 0.01 mol) in DMF (25 ml) at room temperature under stirring. The mixture was heated to 353 K for 5 h. The resulting solution was evaporated to dryness in vacuo, and the residue was treated with cold water, filtered, and crystallized from methanol to give pure product (yield 74%, Rf = 0.45 (silica, CH2Cl2/MeOH, 9/1).
Spectral data: 1H NMR (300 MHz, DMSO, δ(p.p.m.)): 10.40 (s, 1H, C5H); 10.09 (s, 1H, CH=O); 8.36 (dd, 1H, C7H, J=2.4 Hz); 7.96 (m, 3H,C8H, CphH, CphH, J= 28.2 Hz); 7.10 (d, 2H, CphH, CphH, J=9 Hz); 3.83 (s, 3H, OCH3). 13C NMR (75 MHz, DMSO) δ(p.p.m.): 180.84; 161.64; 158.81; 147.76; 138.75; 131.75; 128.32; 125.06; 124.05; 121.11; 117.04; 115.02; 55.87. m/z (M+1): 298.09.
Crystal data, data collection and structure
details are summarized in Table 1. H atoms were located in a difference Fourier map and treated as riding: C–H = 0.93-0.96 Å with Uiso(H) = 1.5 Ueq for methyl H atoms and 1.2 Ueq for other H atoms. The reflection (100) affected by the beam-stop was removed during refinement.Imidazo[1,2-a]pyridines are a very interesting class of α-halo ketone (Sumalatha et al., 2009). The present paper is a continuation of our research devoted to the development of imidazo[1,2-a]pyridines derivatives with potential pharmacological activities (Elaatiaoui et al., 2014;2015).
because of their wide use in medicinal chemistry for the production of various pharmacologically active agents. In addition, various derivatives of imidazo[1,2-a]pyridine show a wide range of biological activities such as anti-inflammatory (Rupert et al., 2003), antitumor (Hranjec et al., 2007), antiviral (Hamdouchi et al., 1999), antibacterial (Rival et al., 1992), antiparasitic (Scribner et al., 2008) and anti-HIV (Bode et al., 2011). The access to the imidazo[1,2-a]pyridine scaffold is generally made by condensation of 2-aminopyridine with a specifically chosenIn the title compound, Fig. 1, the fused five- and six-membered rings of the imidazo[1,2-a]pyridine moiety are virtually coplanar, with a maximum deviation of 0.028 (2) Å for atom C3. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the methoxyphenyl ring and the nitro group, respectively.
In the crystal, molecules are linked by C4–H4···N3, C15–H15A···O3 and C14–H14···O1 hydrogen bonds (Table 1), building layers parallel to (101), as shown in Fig. 2.
For biological activities of derivatives of the title compound, see: Rupert et al. (2003); Hranjec et al. (2007); Hamdouchi et al. (1999); Rival et al. (1992); Scribner et al. (2008); Bode et al. (2011). For the synthesis of similar compounds, see: Sumalatha et al. (2009); Elaatiaoui et al. (2014, 2015).
Phosphorus oxychloride (3.06 g, 0.02 mol) was added to a solution of 2-(4-methoxyphenyl)-5-nitroimidazo[1,2-a]pyridine (2.69 g, 0.01 mol) in DMF (25 ml) at room temperature under stirring. The mixture was heated to 353 K for 5 h. The resulting solution was evaporated to dryness in vacuo, and the residue was treated with cold water, filtered, and crystallized from methanol to give pure product (yield 74%, Rf = 0.45 (silica, CH2Cl2/MeOH, 9/1).
Spectral data: 1H NMR (300 MHz, DMSO, δ(p.p.m.)): 10.40 (s, 1H, C5H); 10.09 (s, 1H, CH=O); 8.36 (dd, 1H, C7H, J=2.4 Hz); 7.96 (m, 3H,C8H, CphH, CphH, J= 28.2 Hz); 7.10 (d, 2H, CphH, CphH, J=9 Hz); 3.83 (s, 3H, OCH3). 13C NMR (75 MHz, DMSO) δ(p.p.m.): 180.84; 161.64; 158.81; 147.76; 138.75; 131.75; 128.32; 125.06; 124.05; 121.11; 117.04; 115.02; 55.87. m/z (M+1): 298.09.
detailsCrystal data, data collection and structure
details are summarized in Table 1. H atoms were located in a difference Fourier map and treated as riding: C–H = 0.93-0.96 Å with Uiso(H) = 1.5 Ueq for methyl H atoms and 1.2 Ueq for other H atoms. The reflection (100) affected by the beam-stop was removed during refinement.Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).C15H11N3O4 | F(000) = 616 |
Mr = 297.27 | Dx = 1.471 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 10.8516 (6) Å | Cell parameters from 3472 reflections |
b = 12.0710 (6) Å | θ = 2.5–28.7° |
c = 10.2631 (5) Å | µ = 0.11 mm−1 |
β = 93.200 (2)° | T = 296 K |
V = 1342.26 (12) Å3 | Block, colourless |
Z = 4 | 0.42 × 0.31 × 0.26 mm |
Bruker X8 APEX diffractometer | 3472 independent reflections |
Radiation source: fine-focus sealed tube | 2139 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.060 |
φ and ω scans | θmax = 28.7°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −14→14 |
Tmin = 0.673, Tmax = 0.746 | k = −16→16 |
25892 measured reflections | l = −13→10 |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.044 | w = 1/[σ2(Fo2) + (0.0468P)2 + 0.3011P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.120 | (Δ/σ)max < 0.001 |
S = 1.02 | Δρmax = 0.21 e Å−3 |
3472 reflections | Δρmin = −0.16 e Å−3 |
200 parameters | Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0038 (11) |
C15H11N3O4 | V = 1342.26 (12) Å3 |
Mr = 297.27 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.8516 (6) Å | µ = 0.11 mm−1 |
b = 12.0710 (6) Å | T = 296 K |
c = 10.2631 (5) Å | 0.42 × 0.31 × 0.26 mm |
β = 93.200 (2)° |
Bruker X8 APEX diffractometer | 3472 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 2139 reflections with I > 2σ(I) |
Tmin = 0.673, Tmax = 0.746 | Rint = 0.060 |
25892 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.21 e Å−3 |
3472 reflections | Δρmin = −0.16 e Å−3 |
200 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | −0.02574 (15) | 0.14080 (13) | 0.14955 (15) | 0.0384 (4) | |
H1 | −0.0116 | 0.0650 | 0.1559 | 0.046* | |
C2 | −0.11433 (16) | 0.19026 (13) | 0.21703 (15) | 0.0396 (4) | |
C3 | −0.13789 (17) | 0.30501 (14) | 0.21067 (18) | 0.0479 (4) | |
H3 | −0.1979 | 0.3366 | 0.2601 | 0.057* | |
C4 | −0.07141 (17) | 0.36854 (14) | 0.13112 (18) | 0.0479 (4) | |
H4 | −0.0867 | 0.4442 | 0.1242 | 0.058* | |
C5 | 0.02062 (16) | 0.31952 (12) | 0.05933 (16) | 0.0397 (4) | |
C6 | 0.14059 (15) | 0.18113 (12) | −0.00409 (15) | 0.0369 (4) | |
C7 | 0.20276 (17) | 0.07630 (13) | 0.00131 (16) | 0.0423 (4) | |
H7 | 0.2746 | 0.0694 | −0.0433 | 0.051* | |
C8 | 0.17220 (16) | 0.28204 (13) | −0.05971 (15) | 0.0377 (4) | |
C9 | 0.27357 (16) | 0.30700 (13) | −0.14343 (15) | 0.0389 (4) | |
C10 | 0.33469 (18) | 0.40926 (14) | −0.12918 (18) | 0.0490 (5) | |
H10 | 0.3104 | 0.4595 | −0.0668 | 0.059* | |
C11 | 0.42963 (19) | 0.43593 (15) | −0.20600 (19) | 0.0547 (5) | |
H11 | 0.4698 | 0.5036 | −0.1945 | 0.066* | |
C12 | 0.46660 (17) | 0.36275 (15) | −0.30113 (17) | 0.0467 (4) | |
C13 | 0.40815 (17) | 0.26118 (14) | −0.31569 (16) | 0.0435 (4) | |
H13 | 0.4330 | 0.2111 | −0.3779 | 0.052* | |
C14 | 0.31262 (17) | 0.23437 (13) | −0.23732 (16) | 0.0422 (4) | |
H14 | 0.2738 | 0.1660 | −0.2479 | 0.051* | |
C15 | 0.5928 (2) | 0.32902 (19) | −0.4794 (2) | 0.0685 (6) | |
H15A | 0.6582 | 0.3633 | −0.5241 | 0.103* | |
H15B | 0.6204 | 0.2588 | −0.4449 | 0.103* | |
H15C | 0.5228 | 0.3180 | −0.5394 | 0.103* | |
N1 | −0.18828 (14) | 0.11943 (13) | 0.29732 (14) | 0.0482 (4) | |
N2 | 0.04176 (12) | 0.20585 (10) | 0.07215 (12) | 0.0356 (3) | |
N3 | 0.09779 (14) | 0.36523 (11) | −0.02137 (14) | 0.0438 (4) | |
O1 | −0.17708 (14) | 0.01936 (11) | 0.28788 (14) | 0.0623 (4) | |
O2 | −0.25834 (15) | 0.16393 (13) | 0.37021 (15) | 0.0741 (5) | |
O3 | 0.16791 (13) | −0.00450 (9) | 0.06039 (13) | 0.0548 (4) | |
O4 | 0.55866 (13) | 0.39871 (12) | −0.37535 (13) | 0.0631 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0429 (9) | 0.0298 (7) | 0.0421 (9) | −0.0019 (7) | −0.0011 (8) | 0.0014 (7) |
C2 | 0.0425 (10) | 0.0377 (8) | 0.0385 (9) | −0.0045 (7) | 0.0019 (8) | −0.0010 (7) |
C3 | 0.0515 (11) | 0.0395 (9) | 0.0532 (11) | 0.0025 (8) | 0.0086 (9) | −0.0072 (8) |
C4 | 0.0546 (11) | 0.0304 (8) | 0.0594 (11) | 0.0055 (8) | 0.0083 (9) | −0.0021 (8) |
C5 | 0.0467 (10) | 0.0270 (7) | 0.0448 (9) | 0.0014 (7) | −0.0011 (8) | 0.0011 (7) |
C6 | 0.0396 (9) | 0.0325 (8) | 0.0385 (8) | −0.0008 (7) | 0.0011 (7) | −0.0006 (7) |
C7 | 0.0463 (10) | 0.0350 (8) | 0.0456 (10) | 0.0034 (7) | 0.0036 (8) | 0.0010 (7) |
C8 | 0.0432 (9) | 0.0326 (8) | 0.0370 (8) | 0.0001 (7) | −0.0026 (7) | 0.0012 (6) |
C9 | 0.0436 (9) | 0.0351 (8) | 0.0378 (9) | −0.0004 (7) | −0.0009 (7) | 0.0040 (7) |
C10 | 0.0588 (12) | 0.0380 (9) | 0.0506 (10) | −0.0050 (8) | 0.0070 (9) | −0.0049 (8) |
C11 | 0.0641 (13) | 0.0406 (9) | 0.0603 (12) | −0.0170 (9) | 0.0103 (10) | −0.0053 (8) |
C12 | 0.0479 (10) | 0.0484 (10) | 0.0441 (10) | −0.0087 (8) | 0.0035 (8) | 0.0026 (8) |
C13 | 0.0490 (11) | 0.0428 (9) | 0.0386 (9) | −0.0031 (8) | 0.0015 (8) | −0.0022 (7) |
C14 | 0.0504 (11) | 0.0342 (8) | 0.0418 (9) | −0.0074 (7) | −0.0004 (8) | 0.0010 (7) |
C15 | 0.0619 (14) | 0.0834 (16) | 0.0622 (13) | −0.0196 (12) | 0.0228 (11) | −0.0136 (11) |
N1 | 0.0485 (9) | 0.0496 (9) | 0.0465 (8) | −0.0048 (7) | 0.0042 (7) | 0.0000 (7) |
N2 | 0.0399 (8) | 0.0277 (6) | 0.0388 (7) | 0.0004 (5) | −0.0002 (6) | 0.0000 (5) |
N3 | 0.0514 (9) | 0.0316 (7) | 0.0487 (8) | 0.0017 (6) | 0.0044 (7) | 0.0039 (6) |
O1 | 0.0686 (10) | 0.0432 (7) | 0.0765 (10) | −0.0044 (6) | 0.0153 (8) | 0.0124 (7) |
O2 | 0.0803 (11) | 0.0707 (10) | 0.0752 (10) | −0.0053 (8) | 0.0386 (9) | −0.0078 (8) |
O3 | 0.0638 (9) | 0.0343 (6) | 0.0676 (8) | 0.0080 (6) | 0.0155 (7) | 0.0104 (6) |
O4 | 0.0654 (9) | 0.0664 (9) | 0.0593 (8) | −0.0241 (7) | 0.0201 (7) | −0.0072 (7) |
C1—C2 | 1.354 (2) | C9—C14 | 1.386 (2) |
C1—N2 | 1.360 (2) | C9—C10 | 1.405 (2) |
C1—H1 | 0.9300 | C10—C11 | 1.370 (3) |
C2—C3 | 1.409 (2) | C10—H10 | 0.9300 |
C2—N1 | 1.459 (2) | C11—C12 | 1.392 (3) |
C3—C4 | 1.357 (2) | C11—H11 | 0.9300 |
C3—H3 | 0.9300 | C12—O4 | 1.361 (2) |
C4—C5 | 1.405 (2) | C12—C13 | 1.385 (2) |
C4—H4 | 0.9300 | C13—C14 | 1.385 (2) |
C5—N3 | 1.330 (2) | C13—H13 | 0.9300 |
C5—N2 | 1.3961 (19) | C14—H14 | 0.9300 |
C6—N2 | 1.395 (2) | C15—O4 | 1.424 (2) |
C6—C8 | 1.396 (2) | C15—H15A | 0.9600 |
C6—C7 | 1.434 (2) | C15—H15B | 0.9600 |
C7—O3 | 1.2197 (19) | C15—H15C | 0.9600 |
C7—H7 | 0.9300 | N1—O1 | 1.2184 (19) |
C8—N3 | 1.360 (2) | N1—O2 | 1.220 (2) |
C8—C9 | 1.464 (2) | ||
C2—C1—N2 | 117.71 (14) | C11—C10—H10 | 119.6 |
C2—C1—H1 | 121.1 | C9—C10—H10 | 119.6 |
N2—C1—H1 | 121.1 | C10—C11—C12 | 120.65 (17) |
C1—C2—C3 | 122.79 (16) | C10—C11—H11 | 119.7 |
C1—C2—N1 | 117.32 (15) | C12—C11—H11 | 119.7 |
C3—C2—N1 | 119.88 (16) | O4—C12—C13 | 124.62 (17) |
C4—C3—C2 | 118.83 (16) | O4—C12—C11 | 116.07 (16) |
C4—C3—H3 | 120.6 | C13—C12—C11 | 119.30 (17) |
C2—C3—H3 | 120.6 | C12—C13—C14 | 119.81 (16) |
C3—C4—C5 | 119.67 (16) | C12—C13—H13 | 120.1 |
C3—C4—H4 | 120.2 | C14—C13—H13 | 120.1 |
C5—C4—H4 | 120.2 | C13—C14—C9 | 121.56 (15) |
N3—C5—N2 | 111.14 (14) | C13—C14—H14 | 119.2 |
N3—C5—C4 | 129.99 (15) | C9—C14—H14 | 119.2 |
N2—C5—C4 | 118.85 (15) | O4—C15—H15A | 109.5 |
N2—C6—C8 | 104.88 (13) | O4—C15—H15B | 109.5 |
N2—C6—C7 | 122.83 (14) | H15A—C15—H15B | 109.5 |
C8—C6—C7 | 131.31 (16) | O4—C15—H15C | 109.5 |
O3—C7—C6 | 124.53 (17) | H15A—C15—H15C | 109.5 |
O3—C7—H7 | 117.7 | H15B—C15—H15C | 109.5 |
C6—C7—H7 | 117.7 | O1—N1—O2 | 123.60 (16) |
N3—C8—C6 | 111.25 (15) | O1—N1—C2 | 118.41 (15) |
N3—C8—C9 | 119.68 (14) | O2—N1—C2 | 118.00 (15) |
C6—C8—C9 | 128.98 (15) | C1—N2—C6 | 131.33 (13) |
C14—C9—C10 | 117.84 (16) | C1—N2—C5 | 122.11 (14) |
C14—C9—C8 | 123.12 (15) | C6—N2—C5 | 106.55 (13) |
C10—C9—C8 | 119.04 (15) | C5—N3—C8 | 106.16 (13) |
C11—C10—C9 | 120.81 (17) | C12—O4—C15 | 117.45 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···N3i | 0.93 | 2.53 | 3.412 (2) | 158 |
C15—H15A···O3ii | 0.96 | 2.52 | 3.423 (2) | 158 |
C14—H14···O1iii | 0.93 | 2.50 | 3.425 (2) | 177 |
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, y+1/2, −z−1/2; (iii) −x, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···N3i | 0.93 | 2.53 | 3.412 (2) | 158.2 |
C15—H15A···O3ii | 0.96 | 2.52 | 3.423 (2) | 157.7 |
C14—H14···O1iii | 0.93 | 2.50 | 3.425 (2) | 176.6 |
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, y+1/2, −z−1/2; (iii) −x, −y, −z. |
Acknowledgements
The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.
References
Bode, M. L., Gravestock, D., Moleele, S. S., van der Westhuyzen, C. W., Pelly, S. C., Steenkamp, P. A., Hoppe, H. C., Khan, T. & Nkabinde, L. A. (2011). Bioorg. Med. Chem. 19, 4227–4237. Web of Science CrossRef CAS PubMed Google Scholar
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Elaatiaoui, A., Koudad, M., Saddik, R., Benchat, N. & El Ammari, L. (2014). Acta Cryst. E70, o1189–o1190. CSD CrossRef IUCr Journals Google Scholar
Elaatiaoui, A., Saddik, R., Benchat, N., Saadi, M. & El Ammari, L. (2015). Acta Cryst. E71, o803–o804. Web of Science CSD CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Hamdouchi, C., de Blas, J., del Prado, M., Gruber, J., Heinz, B. A. & Vance, L. (1999). J. Med. Chem. 42, 50–59. Web of Science CrossRef CAS PubMed Google Scholar
Hranjec, M., Kralj, M., Piantanida, I., Sedić, M., Šuman, L., Pavelić, K. & Karminski-Zamola, G. (2007). J. Med. Chem. 50, 5696–5711. Web of Science CrossRef PubMed CAS Google Scholar
Rival, Y., Grassy, G. & Michel, G. (1992). Chem. Pharm. Bull. 40, 1170–1176. CrossRef PubMed CAS Google Scholar
Rupert, K. C., Henry, J. R., Dodd, J. H., Wadsworth, S. A., Cavender, D. E., Olini, G. C., Fahmy, B. & Siekierka, J. J. (2003). Bioorg. Med. Chem. Lett. 13, 347–350. Web of Science CrossRef PubMed CAS Google Scholar
Scribner, A., Dennis, R., Lee, S., Ouvry, G., Perrey, D., Fisher, M., Wyvratt, M., Leavitt, P., Liberator, P., Gurnett, A., Brown, C., Mathew, J., Thompson, D., Schmatz, D. & Biftu, T. (2008). Eur. J. Med. Chem. 43, 1123–1151. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sumalatha, Y., Reddy, T. R., Reddy, P. P. & Satyanarayana, B. (2009). Arkivoc, pp. 315–320. Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
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