organic compounds
2,10-Bis(3-bromophenyl)-3,7,11,15-tetraoxa-8,16-diazatricyclo[12.2.1.16,9]octadeca-1(16),6(18),8,14(17)-tetraene
aSchool of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757, Republic of Korea, and bGwangju Branch, Korea Basic Science Institute, Gwangju 500-757, Republic of Korea
*Correspondence e-mail: hyungkim@chonnam.ac.kr
The title compound, C24H20Br2N2O4, is an 18-membered tricycle including two isoxazole rings. The contains one half of the formula unit; a centre of inversion is located at the centroid of the compound. The dihedral angle between adjacent isoxazole and benzene rings is 84.0 (2)°. The compound displays intra- and intermolecular π–π stacking interactions between the isoxazole rings, the shortest centroid–centroid distances being 3.837 (3) and 3.634 (3) Å, respectively. The molecules are stacked in columns along the a axis with short Br⋯Br contacts [3.508 (1) Å].
Related literature
For the biological activity of isoxazole derivatives, see: Kim et al. (1994, 1997); Lang & Lin (1984). For the syntheses of various pyrano[3,4-c]isoxzole derivatives, see: Kim et al. (1999).
Experimental
Crystal data
|
Data collection: SMART (Bruker, 2000); cell SAINT (Bruker, 2000); data reduction: SAINT; 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 PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536810028813/ng5004sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810028813/ng5004Isup2.hkl
A mixture of 1-bromo-3-[1-(but-3-ynyloxy)-2-nitroethyl]benzene (1.49 g, 5 mmol), phenyl isocyanate (2.97 g, 25 mmol) and Et3N (51 mg, 0.5 mmol) in dry benzene (30 ml) was stirred for 12 h at 25 °C under nitrogen atmosphere. Water (1 ml) was added and the mixture was stirred for 2 h at which time the solids were removed by vacuum filtration. The filtrate was dried (MgSO4) and concentrated in vacuo to give crude product, which was column chromatographed (SiO2) by eluting with a mixture of n-hexane/EtOAc (10:1) to afford the title compound (34 mg, 1.2%) as a white solid. Crystals suitable for X-ray analysis were obtained by slow evaporation from an n-hexane/EtOAc solution. Mp 231 °C. 1H NMR (600 MHz, CDCl3): δ 7.57 (s, 2H, Ar), 7.41–7.18 (m, 6H, Ar), 5.41 (s, 2H, isoxazole), 5.37 (s, 2H, –O—CH-C6H4Br), 4.19 (dt, 2H, J = 10.2 Hz, 3.0 Hz, –CH2CHH—O), 3.67 (bt, 2H, J = 10.2 Hz, –CH2CHH-O–), 3.15 (ddd, 2H, J = 16.2 Hz, 12.6 Hz, 3.0 Hz, –CHH—CH2O–), 2.77 (bd, J = 16.2 Hz, –CHH-CH2O–). 13C NMR (150 MHz, CDCl3): δ 172.71, 164.13, 141.11, 131.00, 129.98, 128.74, 124.43, 122.61, 98.90, 74.22, 67.40, 27.91.
H atoms were positioned geometrically and allowed to ride on their respective parent atoms [C—H = 0.95 (CH, sp2), 1.00 (CH, sp3) or 0.99 Å (CH2) and Uiso(H) = 1.2Ueq(C)]. The highest peak (1.25 e Å-3) and the deepest hole (-1.87 e Å-3) in the difference Fourier map are located 1.46 Å and 0.89 Å from the Br1 atom, respectively.
Many isoxazole derivatives are known to have a variety of biological activities in pharmaceutical and agricultural areas (Kim et al., 1994, 1997; Lang & Lin, 1984). Recently we reported that the syntheses of various pyrano[3,4-c]isoxzole derivatives by means of the intramolecular 1,3-dipolar
of a nitrile oxide containing an alkyne moiety within the structure and that these fused isoxazoles displayed fungicidal activities against some plant pathogens (Kim et al., 1999). During the chromatographic purification of the crude product, we isolated an unexpected macrocylic isoxazole compound which was formed by intermolecular process.The π-π interactions between the isoxazole rings (the symmetry operations for second planes: -x,-y,-z and -x,1 - y,-z, respectively), the shortest centroid-centroid distance being 3.837 (3) Å and 3.634 (3) Å, respectively. The parallel planes are shifted for 1.048 Å and 1.936 Å, respectively (Fig. 2). There may also be weak intermolecular π-π interactions between adjacent benzene rings, with a shortest centroid-centroid distance of 4.453 (4) Å. The molecules are stacked in columns along the a axis and the Br···Br contacts are present. The shortest Br1···Br1a [symmetry code: (a) 2 - x,-y,1 - z] distance is 3.508 (1) Å.
of the title compound, C24H20Br2N2O4, contains one half of the formula unit; a centre of inversion is located at the midpoint of the compound (Fig. 1). The C7 and C11 atoms lie in the isoxazole ring plane with the largest deviation of 0.055 (9) Å (C7) from the least-squares plane of the isoxazole ring. The compound displays intra- and intermolecularFor the biological activity of isoxazole derivatives, see: Kim et al. (1994, 1997); Lang & Lin (1984). For the syntheses of various pyrano[3,4-c]isoxzole derivatives, see: Kim et al. (1999).
Data collection: SMART (Bruker, 2000); cell
SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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 PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C24H20Br2N2O4 | Z = 1 |
Mr = 560.24 | F(000) = 280 |
Triclinic, P1 | Dx = 1.704 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 5.6446 (4) Å | Cell parameters from 2388 reflections |
b = 7.3703 (5) Å | θ = 2.8–28.1° |
c = 13.701 (1) Å | µ = 3.75 mm−1 |
α = 93.735 (1)° | T = 200 K |
β = 99.564 (1)° | Plate, colorless |
γ = 102.363 (1)° | 0.34 × 0.26 × 0.17 mm |
V = 546.03 (7) Å3 |
Bruker SMART 1000 CCD diffractometer | 2645 independent reflections |
Radiation source: fine-focus sealed tube | 2040 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.015 |
φ and ω scans | θmax = 28.3°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −7→6 |
Tmin = 0.797, Tmax = 1.000 | k = −9→9 |
4051 measured reflections | l = −16→18 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.152 | H-atom parameters constrained |
S = 1.30 | w = 1/[σ2(Fo2) + (0.P)2 + 3.5324P] where P = (Fo2 + 2Fc2)/3 |
2645 reflections | (Δ/σ)max < 0.001 |
145 parameters | Δρmax = 1.25 e Å−3 |
0 restraints | Δρmin = −1.87 e Å−3 |
C24H20Br2N2O4 | γ = 102.363 (1)° |
Mr = 560.24 | V = 546.03 (7) Å3 |
Triclinic, P1 | Z = 1 |
a = 5.6446 (4) Å | Mo Kα radiation |
b = 7.3703 (5) Å | µ = 3.75 mm−1 |
c = 13.701 (1) Å | T = 200 K |
α = 93.735 (1)° | 0.34 × 0.26 × 0.17 mm |
β = 99.564 (1)° |
Bruker SMART 1000 CCD diffractometer | 2645 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 2040 reflections with I > 2σ(I) |
Tmin = 0.797, Tmax = 1.000 | Rint = 0.015 |
4051 measured reflections |
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.152 | H-atom parameters constrained |
S = 1.30 | Δρmax = 1.25 e Å−3 |
2645 reflections | Δρmin = −1.87 e Å−3 |
145 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. |
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 | ||
Br1 | 0.78777 (12) | 0.13416 (10) | 0.45968 (6) | 0.0464 (2) | |
O1 | −0.0873 (7) | 0.2957 (6) | −0.0511 (3) | 0.0304 (9) | |
O2 | −0.0557 (7) | −0.0026 (5) | 0.2100 (3) | 0.0323 (9) | |
N1 | −0.1737 (8) | 0.2688 (7) | 0.0394 (4) | 0.0315 (10) | |
C1 | 0.5786 (11) | 0.2773 (8) | 0.3908 (4) | 0.0336 (12) | |
C2 | 0.3670 (11) | 0.1843 (8) | 0.3295 (4) | 0.0333 (12) | |
H2 | 0.3226 | 0.0517 | 0.3216 | 0.040* | |
C3 | 0.2166 (10) | 0.2874 (8) | 0.2784 (4) | 0.0288 (11) | |
C4 | 0.2855 (12) | 0.4808 (8) | 0.2927 (5) | 0.0383 (14) | |
H4 | 0.1827 | 0.5521 | 0.2588 | 0.046* | |
C5 | 0.5037 (13) | 0.5714 (9) | 0.3561 (5) | 0.0443 (16) | |
H5 | 0.5493 | 0.7040 | 0.3655 | 0.053* | |
C6 | 0.6540 (12) | 0.4683 (9) | 0.4054 (5) | 0.0411 (15) | |
H6 | 0.8049 | 0.5278 | 0.4482 | 0.049* | |
C7 | −0.0170 (10) | 0.1934 (7) | 0.2048 (4) | 0.0286 (11) | |
H7 | −0.1606 | 0.2385 | 0.2229 | 0.034* | |
C8 | 0.0115 (9) | 0.2363 (7) | 0.1015 (4) | 0.0254 (11) | |
C9 | 0.2206 (10) | 0.2402 (7) | 0.0570 (4) | 0.0273 (11) | |
H9 | 0.3764 | 0.2208 | 0.0867 | 0.033* | |
C10 | 0.1503 (9) | 0.2772 (7) | −0.0368 (4) | 0.0263 (11) | |
C11 | 0.2785 (10) | 0.2954 (8) | −0.1230 (4) | 0.0303 (12) | |
H11A | 0.4454 | 0.3774 | −0.1016 | 0.036* | |
H11B | 0.1857 | 0.3539 | −0.1749 | 0.036* | |
C12 | −0.2998 (10) | −0.1054 (8) | 0.1658 (4) | 0.0310 (12) | |
H12A | −0.3729 | −0.0385 | 0.1125 | 0.037* | |
H12B | −0.4066 | −0.1201 | 0.2166 | 0.037* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0331 (3) | 0.0454 (4) | 0.0559 (4) | 0.0092 (3) | −0.0055 (3) | 0.0045 (3) |
O1 | 0.0248 (19) | 0.038 (2) | 0.031 (2) | 0.0108 (16) | 0.0029 (16) | 0.0109 (17) |
O2 | 0.029 (2) | 0.029 (2) | 0.032 (2) | −0.0001 (16) | −0.0033 (16) | 0.0014 (16) |
N1 | 0.023 (2) | 0.040 (3) | 0.032 (3) | 0.008 (2) | 0.0034 (19) | 0.005 (2) |
C1 | 0.034 (3) | 0.034 (3) | 0.033 (3) | 0.011 (2) | 0.005 (2) | 0.006 (2) |
C2 | 0.035 (3) | 0.027 (3) | 0.035 (3) | 0.002 (2) | 0.009 (2) | −0.006 (2) |
C3 | 0.031 (3) | 0.026 (3) | 0.027 (3) | 0.004 (2) | 0.003 (2) | 0.003 (2) |
C4 | 0.042 (3) | 0.029 (3) | 0.038 (3) | 0.007 (3) | −0.006 (3) | 0.002 (3) |
C5 | 0.052 (4) | 0.026 (3) | 0.042 (4) | −0.004 (3) | −0.008 (3) | 0.000 (3) |
C6 | 0.033 (3) | 0.044 (4) | 0.035 (3) | −0.008 (3) | −0.004 (3) | 0.002 (3) |
C7 | 0.028 (3) | 0.025 (3) | 0.031 (3) | 0.006 (2) | 0.003 (2) | 0.000 (2) |
C8 | 0.025 (3) | 0.022 (2) | 0.030 (3) | 0.007 (2) | 0.002 (2) | 0.002 (2) |
C9 | 0.022 (2) | 0.026 (3) | 0.034 (3) | 0.005 (2) | 0.002 (2) | 0.004 (2) |
C10 | 0.022 (2) | 0.022 (2) | 0.032 (3) | 0.0018 (19) | 0.002 (2) | 0.004 (2) |
C11 | 0.029 (3) | 0.027 (3) | 0.032 (3) | 0.002 (2) | 0.005 (2) | 0.004 (2) |
C12 | 0.023 (3) | 0.031 (3) | 0.038 (3) | 0.003 (2) | 0.005 (2) | 0.007 (2) |
Br1—C1 | 1.921 (6) | C5—H5 | 0.9500 |
O1—C10 | 1.360 (6) | C6—H6 | 0.9500 |
O1—N1 | 1.416 (6) | C7—C8 | 1.497 (8) |
O2—C7 | 1.423 (6) | C7—H7 | 1.0000 |
O2—C12 | 1.433 (6) | C8—C9 | 1.412 (7) |
N1—C8 | 1.308 (7) | C9—C10 | 1.344 (7) |
C1—C2 | 1.358 (8) | C9—H9 | 0.9500 |
C1—C6 | 1.372 (9) | C10—C11 | 1.483 (8) |
C2—C3 | 1.391 (8) | C11—C12i | 1.520 (8) |
C2—H2 | 0.9500 | C11—H11A | 0.9900 |
C3—C4 | 1.386 (8) | C11—H11B | 0.9900 |
C3—C7 | 1.521 (7) | C12—C11i | 1.520 (8) |
C4—C5 | 1.391 (8) | C12—H12A | 0.9900 |
C4—H4 | 0.9500 | C12—H12B | 0.9900 |
C5—C6 | 1.381 (9) | ||
C10—O1—N1 | 107.8 (4) | O2—C7—H7 | 109.7 |
C7—O2—C12 | 114.0 (4) | C8—C7—H7 | 109.7 |
C8—N1—O1 | 105.5 (4) | C3—C7—H7 | 109.7 |
C2—C1—C6 | 123.7 (6) | N1—C8—C9 | 111.9 (5) |
C2—C1—Br1 | 118.4 (5) | N1—C8—C7 | 120.4 (5) |
C6—C1—Br1 | 117.9 (5) | C9—C8—C7 | 127.6 (5) |
C1—C2—C3 | 118.6 (5) | C10—C9—C8 | 104.7 (5) |
C1—C2—H2 | 120.7 | C10—C9—H9 | 127.6 |
C3—C2—H2 | 120.7 | C8—C9—H9 | 127.6 |
C4—C3—C2 | 119.1 (5) | C9—C10—O1 | 110.0 (5) |
C4—C3—C7 | 119.1 (5) | C9—C10—C11 | 132.4 (5) |
C2—C3—C7 | 121.7 (5) | O1—C10—C11 | 117.5 (5) |
C3—C4—C5 | 120.7 (6) | C10—C11—C12i | 110.7 (5) |
C3—C4—H4 | 119.6 | C10—C11—H11A | 109.5 |
C5—C4—H4 | 119.6 | C12i—C11—H11A | 109.5 |
C6—C5—C4 | 119.8 (6) | C10—C11—H11B | 109.5 |
C6—C5—H5 | 120.1 | C12i—C11—H11B | 109.5 |
C4—C5—H5 | 120.1 | H11A—C11—H11B | 108.1 |
C1—C6—C5 | 118.0 (6) | O2—C12—C11i | 107.4 (4) |
C1—C6—H6 | 121.0 | O2—C12—H12A | 110.2 |
C5—C6—H6 | 121.0 | C11i—C12—H12A | 110.2 |
O2—C7—C8 | 109.7 (4) | O2—C12—H12B | 110.2 |
O2—C7—C3 | 107.8 (4) | C11i—C12—H12B | 110.2 |
C8—C7—C3 | 110.1 (5) | H12A—C12—H12B | 108.5 |
C10—O1—N1—C8 | 0.0 (6) | C2—C3—C7—C8 | −113.0 (6) |
C6—C1—C2—C3 | −0.1 (10) | O1—N1—C8—C9 | 0.0 (6) |
Br1—C1—C2—C3 | −179.2 (4) | O1—N1—C8—C7 | −177.6 (4) |
C1—C2—C3—C4 | −0.8 (9) | O2—C7—C8—N1 | 100.4 (6) |
C1—C2—C3—C7 | 177.1 (6) | C3—C7—C8—N1 | −141.0 (5) |
C2—C3—C4—C5 | 0.8 (10) | O2—C7—C8—C9 | −76.8 (7) |
C7—C3—C4—C5 | −177.1 (6) | C3—C7—C8—C9 | 41.8 (7) |
C3—C4—C5—C6 | 0.1 (11) | N1—C8—C9—C10 | 0.0 (6) |
C2—C1—C6—C5 | 1.1 (10) | C7—C8—C9—C10 | 177.4 (5) |
Br1—C1—C6—C5 | −179.9 (5) | C8—C9—C10—O1 | 0.0 (6) |
C4—C5—C6—C1 | −1.0 (11) | C8—C9—C10—C11 | −178.2 (5) |
C12—O2—C7—C8 | −76.1 (6) | N1—O1—C10—C9 | 0.0 (6) |
C12—O2—C7—C3 | 164.0 (5) | N1—O1—C10—C11 | 178.6 (4) |
C4—C3—C7—O2 | −175.5 (5) | C9—C10—C11—C12i | 73.1 (7) |
C2—C3—C7—O2 | 6.6 (7) | O1—C10—C11—C12i | −105.0 (5) |
C4—C3—C7—C8 | 64.8 (7) | C7—O2—C12—C11i | 147.7 (5) |
Symmetry code: (i) −x, −y, −z. |
Experimental details
Crystal data | |
Chemical formula | C24H20Br2N2O4 |
Mr | 560.24 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 200 |
a, b, c (Å) | 5.6446 (4), 7.3703 (5), 13.701 (1) |
α, β, γ (°) | 93.735 (1), 99.564 (1), 102.363 (1) |
V (Å3) | 546.03 (7) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 3.75 |
Crystal size (mm) | 0.34 × 0.26 × 0.17 |
Data collection | |
Diffractometer | Bruker SMART 1000 CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.797, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4051, 2645, 2040 |
Rint | 0.015 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.152, 1.30 |
No. of reflections | 2645 |
No. of parameters | 145 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.25, −1.87 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009).
Acknowledgements
This study was supported financially by Chonnam National University, 2008.
References
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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.
Many isoxazole derivatives are known to have a variety of biological activities in pharmaceutical and agricultural areas (Kim et al., 1994, 1997; Lang & Lin, 1984). Recently we reported that the syntheses of various pyrano[3,4-c]isoxzole derivatives by means of the intramolecular 1,3-dipolar cycloaddition of a nitrile oxide containing an alkyne moiety within the structure and that these fused isoxazoles displayed fungicidal activities against some plant pathogens (Kim et al., 1999). During the chromatographic purification of the crude product, we isolated an unexpected macrocylic isoxazole compound which was formed by intermolecular cycloaddition process.
The asymmetric unit of the title compound, C24H20Br2N2O4, contains one half of the formula unit; a centre of inversion is located at the midpoint of the compound (Fig. 1). The C7 and C11 atoms lie in the isoxazole ring plane with the largest deviation of 0.055 (9) Å (C7) from the least-squares plane of the isoxazole ring. The compound displays intra- and intermolecular π-π interactions between the isoxazole rings (the symmetry operations for second planes: -x,-y,-z and -x,1 - y,-z, respectively), the shortest centroid-centroid distance being 3.837 (3) Å and 3.634 (3) Å, respectively. The parallel planes are shifted for 1.048 Å and 1.936 Å, respectively (Fig. 2). There may also be weak intermolecular π-π interactions between adjacent benzene rings, with a shortest centroid-centroid distance of 4.453 (4) Å. The molecules are stacked in columns along the a axis and the Br···Br contacts are present. The shortest Br1···Br1a [symmetry code: (a) 2 - x,-y,1 - z] distance is 3.508 (1) Å.