organic compounds
N-(2,6-Dichlorophenyl)-5-methyl-1,2-oxazole-4-carboxamide monohydrate
aState Key Laboratory of Materials-Oriented Chemical Engineering, School of Pharmaceutical Sciences, Nanjing University of Technology, Xinmofan Road No. 5 Nanjing, Nanjing 210009, People's Republic of China
*Correspondence e-mail: dc_wang@hotmail.com
In the title compound, C11H8Cl2N2O2·H2O, the dihedral angle between the benzene and isoxazole rings is 59.10 (7)°. In the crystal, the components are linked by N—H⋯O and O—H⋯O hydrogen bonds into a three-dimensional network. The is further stabilized by π–π stacking interactions [centroid–centroid distance = 3.804 (2) Å].
Related literature
The title compound was synthesised as a new and potent immunomodulating leflunomide {systematic name: 5-methyl-N-[4-(trifluoromethyl)phenyl]-isoxazole-4-carboxamide} analog (Huang et al., 2003). For the application of leflunomide in the treatment of rheumatoid arthritis, see: Shaw et al. (2011); Schattenkirchner et al. (2000).
Experimental
Crystal data
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Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell CAD-4 EXPRESS; 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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
https://doi.org/10.1107/S1600536811044734/gw2111sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811044734/gw2111Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536811044734/gw2111Isup3.cml
A solution of 0.005 mole of 5-methylisoxazole-4-carboxylic acid chloride (0.73 g) in 2 ml of acetonitrile is added dropwise, while stirring,to 0.01 mole of 2,6-dichloroaniline(1.62 g),dissolved in 15 ml of acetonitrile at room temperature.After stirring for 20 minutes,the precipitated 2,6-dichloroaniline hydrochloride is filtered off and washed with 10 ml portions of acetonitrile,and the combined filtrates are concentrated under reduced pressure.10.6 g(78.5% of theory) of white crytalline 5-methyl-N-(2,6-dichlorophenyl)isoxazole-4-carboxamide are thus obtained. Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of an methylbenzene solution.
H atoms of the water molecule were located in a difference Fourier map and refined as riding with O—H = 0.85 Å, with Uiso(H) = 1.5 Ueq. Carbon and nitrogen bound H atoms were placed at calculated positions and were treated as riding on the parent C or N atoms with C—H = 0.96 (methyl), 0.97 (methylene) and N—H = 0.86 Å, Uiso(H) = 1.2 or 1.5 Ueq(C, N).
Leflunomide is one of the most effective isoxazole-containing heterocyclic disease modifying anti-rheumatic drugs for treating rheumatoid arthritis(Shaw et al., 2011; Schattenkirchner et al., 2000). The title compound 5-methyl-N-(2,6-dichlorophenyl)isoxazole -4-carboxamide monohydrate,(I), was synthesized as a novel and potent immunomodulating leflunomide analog (Huang, et al., 2003). We report herein the
of the title compound.As illustrated in Fig. 1, the molecular structure of the title compound is not planar and consists of one 5-methyl-N-(2,6-dichlorophenyl)isoxazole-4-carboxamide molecule and one solvate water molecule. The dihedral angle between the C1—C6 benzene and the C8—C10/N2/O2 isoxazole ring is 59.10 (7) °. The central nitrogen atom (N1) and carbon atom (C7) are nearly coplanar with the benzene ring and the benzoyl rings[N1—C6—C5—C4 torsion angles = -178.5 (3) ° and C7—C8—C9—O2 torsion angles = -179.2 (3) °], respectively. The length of the C10=N2 double bond is 1.299 (5) Å, slightly longer than standard 1.28 Å value of a C=N double bond. The
is stabilized by N—H···O and O—H···O hydrogen bonds (Table 1), which is further stabilized by /p-/p stacking interactions.The title compound was synthesised as a new and potent immunomodulating leflunomide {systematic name: 5-methyl-N-[4-(trifluoromethyl)phenyl]-isoxazole-4-carboxamide} analog (Huang et al., 2003). For the application of leflunomide in the treatment of rheumatoid arthritis, see: Shaw et al. (2011); Schattenkirchner et al. (2000).
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell
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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. The structure of the title compound, showing the atomic numbering scheme. Non-H atoms are shown with 30% probability displacement ellipsoids. |
C11H8Cl2N2O2·H2O | Dx = 1.480 Mg m−3 |
Mr = 289.11 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pna21 | Cell parameters from 25 reflections |
a = 12.047 (2) Å | θ = 9–13° |
b = 8.2290 (16) Å | µ = 0.50 mm−1 |
c = 13.086 (3) Å | T = 293 K |
V = 1297.3 (4) Å3 | Block, white |
Z = 4 | 0.30 × 0.20 × 0.10 mm |
F(000) = 592 |
Enraf–Nonius CAD-4 diffractometer | 1906 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.000 |
Graphite monochromator | θmax = 25.4°, θmin = 3.0° |
ω/2θ scans | h = 0→14 |
Absorption correction: ψ scan (SADABS; Sheldrick, 1996) | k = −9→0 |
Tmin = 0.864, Tmax = 0.952 | l = −15→15 |
2333 measured reflections | 3 standard reflections every 200 reflections |
2333 independent reflections | intensity decay: 1% |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.045 | w = 1/[σ2(Fo2) + (0.073P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.118 | (Δ/σ)max < 0.001 |
S = 1.00 | Δρmax = 0.19 e Å−3 |
2333 reflections | Δρmin = −0.18 e Å−3 |
164 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 0.038 (3) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 1107 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.04 (9) |
C11H8Cl2N2O2·H2O | V = 1297.3 (4) Å3 |
Mr = 289.11 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 12.047 (2) Å | µ = 0.50 mm−1 |
b = 8.2290 (16) Å | T = 293 K |
c = 13.086 (3) Å | 0.30 × 0.20 × 0.10 mm |
Enraf–Nonius CAD-4 diffractometer | 1906 reflections with I > 2σ(I) |
Absorption correction: ψ scan (SADABS; Sheldrick, 1996) | Rint = 0.000 |
Tmin = 0.864, Tmax = 0.952 | 3 standard reflections every 200 reflections |
2333 measured reflections | intensity decay: 1% |
2333 independent reflections |
R[F2 > 2σ(F2)] = 0.045 | H-atom parameters constrained |
wR(F2) = 0.118 | Δρmax = 0.19 e Å−3 |
S = 1.00 | Δρmin = −0.18 e Å−3 |
2333 reflections | Absolute structure: Flack (1983), 1107 Friedel pairs |
164 parameters | Absolute structure parameter: 0.04 (9) |
1 restraint |
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. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.34861 (10) | −0.10973 (15) | 0.99733 (8) | 0.0766 (4) | |
N1 | 0.4813 (2) | 0.0638 (3) | 0.8429 (2) | 0.0426 (6) | |
H1A | 0.5009 | 0.1294 | 0.8907 | 0.051* | |
O1 | 0.5393 (2) | −0.1120 (4) | 0.7213 (2) | 0.0572 (7) | |
C1 | 0.2951 (3) | −0.0268 (5) | 0.8868 (3) | 0.0482 (9) | |
Cl2 | 0.40753 (8) | 0.20917 (15) | 0.64182 (8) | 0.0679 (3) | |
N2 | 0.8178 (3) | 0.0689 (5) | 0.9349 (3) | 0.0695 (10) | |
C2 | 0.1817 (3) | −0.0353 (5) | 0.8670 (4) | 0.0654 (12) | |
H2B | 0.1340 | −0.0829 | 0.9142 | 0.078* | |
O2 | 0.85611 (19) | −0.0172 (4) | 0.8485 (2) | 0.0633 (8) | |
C3 | 0.1411 (3) | 0.0275 (6) | 0.7769 (4) | 0.0689 (12) | |
H3A | 0.0654 | 0.0213 | 0.7631 | 0.083* | |
C4 | 0.2092 (3) | 0.0973 (5) | 0.7089 (4) | 0.0605 (10) | |
H4A | 0.1807 | 0.1369 | 0.6478 | 0.073* | |
C5 | 0.3222 (3) | 0.1113 (4) | 0.7288 (3) | 0.0479 (8) | |
C6 | 0.3673 (3) | 0.0494 (4) | 0.8180 (3) | 0.0405 (7) | |
C7 | 0.5598 (3) | −0.0226 (4) | 0.7937 (2) | 0.0400 (7) | |
C8 | 0.6743 (3) | −0.0017 (4) | 0.8333 (3) | 0.0447 (8) | |
C9 | 0.7686 (3) | −0.0582 (4) | 0.7899 (3) | 0.0474 (8) | |
C10 | 0.7108 (3) | 0.0774 (5) | 0.9239 (3) | 0.0579 (10) | |
H10A | 0.6636 | 0.1291 | 0.9698 | 0.069* | |
C11 | 0.7943 (3) | −0.1487 (6) | 0.6956 (3) | 0.0623 (11) | |
H11A | 0.8728 | −0.1679 | 0.6919 | 0.094* | |
H11B | 0.7712 | −0.0863 | 0.6374 | 0.094* | |
H11C | 0.7558 | −0.2508 | 0.6962 | 0.094* | |
OW | 0.9991 (2) | 0.2436 (4) | 1.02747 (19) | 0.0577 (7) | |
HWA | 0.9856 | 0.1441 | 1.0398 | 0.069* | |
HWB | 0.9882 | 0.3005 | 1.0807 | 0.069* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0827 (8) | 0.0957 (8) | 0.0513 (6) | −0.0078 (6) | 0.0037 (5) | 0.0203 (6) |
N1 | 0.0319 (13) | 0.0569 (17) | 0.0391 (14) | 0.0007 (12) | −0.0025 (12) | −0.0103 (13) |
O1 | 0.0431 (13) | 0.0740 (18) | 0.0546 (16) | 0.0039 (13) | −0.0028 (12) | −0.0211 (14) |
C1 | 0.045 (2) | 0.055 (2) | 0.0453 (19) | 0.0018 (16) | 0.0044 (16) | 0.0008 (17) |
Cl2 | 0.0573 (6) | 0.0872 (7) | 0.0594 (6) | −0.0051 (5) | 0.0004 (5) | 0.0229 (5) |
N2 | 0.0433 (19) | 0.087 (3) | 0.078 (3) | −0.0051 (17) | −0.0078 (16) | −0.007 (2) |
C2 | 0.041 (2) | 0.069 (3) | 0.086 (3) | −0.0103 (18) | 0.016 (2) | −0.004 (2) |
O2 | 0.0347 (14) | 0.080 (2) | 0.0756 (19) | 0.0004 (12) | 0.0016 (14) | 0.0016 (16) |
C3 | 0.035 (2) | 0.077 (3) | 0.094 (4) | −0.001 (2) | −0.008 (2) | −0.001 (3) |
C4 | 0.039 (2) | 0.070 (3) | 0.073 (3) | 0.0044 (19) | −0.0099 (19) | 0.005 (2) |
C5 | 0.0416 (18) | 0.051 (2) | 0.051 (2) | −0.0009 (16) | −0.0008 (15) | −0.0015 (17) |
C6 | 0.0289 (15) | 0.0504 (18) | 0.0423 (17) | 0.0050 (13) | −0.0009 (13) | −0.0030 (14) |
C7 | 0.0285 (16) | 0.0519 (19) | 0.0397 (18) | 0.0010 (14) | 0.0024 (13) | 0.0005 (16) |
C8 | 0.0377 (17) | 0.0455 (19) | 0.051 (2) | 0.0009 (14) | 0.0019 (16) | 0.0037 (17) |
C9 | 0.0363 (19) | 0.050 (2) | 0.055 (2) | −0.0010 (16) | 0.0024 (16) | 0.0094 (17) |
C10 | 0.038 (2) | 0.077 (3) | 0.059 (2) | −0.0035 (18) | −0.0050 (18) | −0.007 (2) |
C11 | 0.053 (2) | 0.071 (3) | 0.063 (2) | 0.0140 (19) | 0.010 (2) | 0.001 (2) |
OW | 0.0544 (14) | 0.0756 (18) | 0.0430 (12) | −0.0051 (13) | 0.0021 (12) | −0.0017 (12) |
Cl1—C1 | 1.724 (4) | C3—H3A | 0.9300 |
N1—C7 | 1.347 (4) | C4—C5 | 1.391 (5) |
N1—C6 | 1.416 (4) | C4—H4A | 0.9300 |
N1—H1A | 0.8600 | C5—C6 | 1.384 (5) |
O1—C7 | 1.224 (4) | C7—C8 | 1.483 (4) |
C1—C2 | 1.392 (5) | C8—C9 | 1.352 (5) |
C1—C6 | 1.400 (5) | C8—C10 | 1.423 (5) |
Cl2—C5 | 1.733 (4) | C9—C11 | 1.474 (5) |
N2—C10 | 1.299 (5) | C10—H10A | 0.9300 |
N2—O2 | 1.412 (5) | C11—H11A | 0.9600 |
C2—C3 | 1.378 (6) | C11—H11B | 0.9600 |
C2—H2B | 0.9300 | C11—H11C | 0.9600 |
O2—C9 | 1.347 (4) | OW—HWA | 0.8500 |
C3—C4 | 1.340 (6) | OW—HWB | 0.8499 |
C7—N1—C6 | 121.8 (3) | C5—C6—N1 | 123.0 (3) |
C7—N1—H1A | 119.1 | C1—C6—N1 | 119.4 (3) |
C6—N1—H1A | 119.1 | O1—C7—N1 | 123.0 (3) |
C2—C1—C6 | 120.8 (4) | O1—C7—C8 | 121.9 (3) |
C2—C1—Cl1 | 120.2 (3) | N1—C7—C8 | 115.2 (3) |
C6—C1—Cl1 | 119.0 (3) | C9—C8—C10 | 104.4 (3) |
C10—N2—O2 | 105.2 (3) | C9—C8—C7 | 126.5 (3) |
C3—C2—C1 | 119.3 (4) | C10—C8—C7 | 129.2 (3) |
C3—C2—H2B | 120.4 | O2—C9—C8 | 109.4 (3) |
C1—C2—H2B | 120.4 | O2—C9—C11 | 116.0 (3) |
C9—O2—N2 | 109.0 (3) | C8—C9—C11 | 134.6 (4) |
C4—C3—C2 | 120.7 (4) | N2—C10—C8 | 112.0 (4) |
C4—C3—H3A | 119.6 | N2—C10—H10A | 124.0 |
C2—C3—H3A | 119.6 | C8—C10—H10A | 124.0 |
C3—C4—C5 | 120.7 (4) | C9—C11—H11A | 109.5 |
C3—C4—H4A | 119.6 | C9—C11—H11B | 109.5 |
C5—C4—H4A | 119.6 | H11A—C11—H11B | 109.5 |
C6—C5—C4 | 120.8 (4) | C9—C11—H11C | 109.5 |
C6—C5—Cl2 | 119.5 (3) | H11A—C11—H11C | 109.5 |
C4—C5—Cl2 | 119.7 (3) | H11B—C11—H11C | 109.5 |
C5—C6—C1 | 117.6 (3) | HWA—OW—HWB | 110.3 |
C6—C1—C2—C3 | 2.1 (6) | C7—N1—C6—C1 | 109.6 (4) |
Cl1—C1—C2—C3 | −178.1 (4) | C6—N1—C7—O1 | 4.0 (5) |
C10—N2—O2—C9 | −0.8 (4) | C6—N1—C7—C8 | −176.2 (3) |
C1—C2—C3—C4 | −0.5 (7) | O1—C7—C8—C9 | 8.6 (6) |
C2—C3—C4—C5 | −1.5 (7) | N1—C7—C8—C9 | −171.2 (3) |
C3—C4—C5—C6 | 1.8 (6) | O1—C7—C8—C10 | −170.2 (4) |
C3—C4—C5—Cl2 | −177.5 (4) | N1—C7—C8—C10 | 9.9 (6) |
C4—C5—C6—C1 | −0.2 (5) | N2—O2—C9—C8 | 0.6 (4) |
Cl2—C5—C6—C1 | 179.1 (3) | N2—O2—C9—C11 | 179.7 (3) |
C4—C5—C6—N1 | −178.5 (3) | C10—C8—C9—O2 | −0.2 (4) |
Cl2—C5—C6—N1 | 0.8 (5) | C7—C8—C9—O2 | −179.2 (3) |
C2—C1—C6—C5 | −1.8 (5) | C10—C8—C9—C11 | −179.0 (4) |
Cl1—C1—C6—C5 | 178.5 (3) | C7—C8—C9—C11 | 1.9 (7) |
C2—C1—C6—N1 | 176.6 (3) | O2—N2—C10—C8 | 0.7 (5) |
Cl1—C1—C6—N1 | −3.1 (5) | C9—C8—C10—N2 | −0.3 (5) |
C7—N1—C6—C5 | −72.1 (4) | C7—C8—C10—N2 | 178.7 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···OWi | 0.86 | 2.07 | 2.897 (4) | 161 |
OW—HWB···O1ii | 0.85 | 2.00 | 2.839 (3) | 168 |
Symmetry codes: (i) x−1/2, −y+1/2, z; (ii) −x+3/2, y+1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C11H8Cl2N2O2·H2O |
Mr | 289.11 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 293 |
a, b, c (Å) | 12.047 (2), 8.2290 (16), 13.086 (3) |
V (Å3) | 1297.3 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.50 |
Crystal size (mm) | 0.30 × 0.20 × 0.10 |
Data collection | |
Diffractometer | Enraf–Nonius CAD-4 |
Absorption correction | ψ scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.864, 0.952 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2333, 2333, 1906 |
Rint | 0.000 |
(sin θ/λ)max (Å−1) | 0.603 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.118, 1.00 |
No. of reflections | 2333 |
No. of parameters | 164 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.19, −0.18 |
Absolute structure | Flack (1983), 1107 Friedel pairs |
Absolute structure parameter | 0.04 (9) |
Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo,1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···OWi | 0.86 | 2.07 | 2.897 (4) | 160.5 |
OW—HWB···O1ii | 0.85 | 2.00 | 2.839 (3) | 167.6 |
Symmetry codes: (i) x−1/2, −y+1/2, z; (ii) −x+3/2, y+1/2, z+1/2. |
Acknowledgements
The work was supported by the Center of Testing and Analysis, Nanjing University.
References
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Leflunomide is one of the most effective isoxazole-containing heterocyclic disease modifying anti-rheumatic drugs for treating rheumatoid arthritis(Shaw et al., 2011; Schattenkirchner et al., 2000). The title compound 5-methyl-N-(2,6-dichlorophenyl)isoxazole -4-carboxamide monohydrate,(I), was synthesized as a novel and potent immunomodulating leflunomide analog (Huang, et al., 2003). We report herein the crystal structure of the title compound.
As illustrated in Fig. 1, the molecular structure of the title compound is not planar and consists of one 5-methyl-N-(2,6-dichlorophenyl)isoxazole-4-carboxamide molecule and one solvate water molecule. The dihedral angle between the C1—C6 benzene and the C8—C10/N2/O2 isoxazole ring is 59.10 (7) °. The central nitrogen atom (N1) and carbon atom (C7) are nearly coplanar with the benzene ring and the benzoyl rings[N1—C6—C5—C4 torsion angles = -178.5 (3) ° and C7—C8—C9—O2 torsion angles = -179.2 (3) °], respectively. The length of the C10=N2 double bond is 1.299 (5) Å, slightly longer than standard 1.28 Å value of a C=N double bond. The crystal structure is stabilized by N—H···O and O—H···O hydrogen bonds (Table 1), which is further stabilized by /p-/p stacking interactions.