organic compounds
3-{[5-(4-Bromophenyl)imidazo[2,1-b][1,3,4]thiadiazol-2-yl]methyl}-1,2-benzoxazole
aDepartment of Studies in Chemistry, Bangalore University, Bangalore 560 001, India, and bDepartment of Chemistry, Karnatak University, Dharwad 580 003, India
*Correspondence e-mail: noorsb@rediffmail.com
In the title compound, C18H11BrN4OS, the imidazothiadiazole and benzisoxazole rings are individually planar with maximum deviations of 0.025 (3) 0.015 (4) Å, respectively, and are inclined at an angle of 23.51 (7)° with respect to each other. The planes of the imidazothiadiazole and bromophenyl rings are inclined at an angle of 27.34 (3)°. In the crystal, intermolecular C—H⋯N interactions result in chains of molecules along the b and c axes. Moreover, C—H⋯O interactions result in centrosymmetric head-to-head dimers with R22(24) graph-set motifs. The molecular packing is further stabilized by π–π stacking interactions between the imidazole rings with a shortest centroid–centroid distance of 3.492 (3) Å. In addition, C—H⋯π interactions are observed in the crystal structure.
Related literature
For the biological activity of benzisoxazole derivatives, see: Priya et al. (2005). For the preparation of the title compound, see: Lamani et al. (2009). For a related structure, see: Sun & Zhang (2009). For graph-set notation, see: Bernstein et al. (1995).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 1998); cell SAINT-Plus (Bruker, 1998); data reduction: SAINT-Plus; 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 CAMERON (Watkin et al., 1996); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S1600536810052232/pv2359sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810052232/pv2359Isup2.hkl
The title compound was synthesized by following the procedure reported earlier (Lamani et al., 2009) and suitable crystals for X-ray crystallographic analysis were grown from a solution of dimethylformamide by slow evaporation at room temperature.
The H atoms were placed at calculated positions in the riding model approximation with N—H = 0.86 and C—H = 0.97 Å, and Uiso(H) = 1.2Ueq(N/C).
Benzisoxazole derivatives are known to possess important biological activities (Priya et al., 2005). In view of increasing importance of the heterocycles in pharmaceutical and biological fields, it was considered of interest to synthesize some new chemical entities incorporating two active pharmacophores in a single molecular frame work and to evaluate their biological activities. In the title compound (Fig. 1), the fused imidazothiadiazole ring system is linked to a benzisoxazole and a bromophenyl moieties. The imidazothiadiazole (S1/N1–N3/C7–C10) and benzisoxazole (O1/N4/C12–C18) rings are individually planar similar to those reported earlier (Sun & Zhang, 2009) with maximum deviations 0.025 (3) Å for N2 and 0.015 (4) Å for C17, respectively. The mean-plane of benzisoxazole makes a dihedral angle of 23.51 (7)° with the mean-plane of the imidazothiadiazole ring. The planes of the imidazothiadiazole and bromophenyl rings are inclined at an angle 27.34 (3)° with each other. The differences in bond lengths S1—C9 (1.734 (5) Å) and S1—C10 (1.757 (5) Å) indicate that the π-π stacking interactions between imidazo rings (Cg3) with the shortest centroid–centroid distance 3.492 (3) Å. In addition, π-ring interactions of the type C—H···Cg (Cg being the centroids of rings C1–C6 and C13–C18) are also observed in the details have been provided in Table 1.
caused by the imidazole ring is stronger than that caused by the thiadiazole ring. In the intermolecular interactions C8—H8···N1 result in chains of molecules along the c-axis and C11—H11B···N1 interactions result in chains of molecules along the b-axis. Moreover, C2—H2···O1 interactions result in centrosymmetric head-to-head dimers corresponding to R22(24) graph set motif (Bernstein et al., 1995) (Fig. 2). The molecular packing is further stabilized byFor the biological activity of benzisoxazole derivatives, see: Priya et al. (2005). For the preparation of the title compound, see: Lamani et al. (2009). For a related structure, see: Sun & Zhang (2009). For graph-set notation, see: Bernstein et al. (1995).
Data collection: SMART (Bruker, 1998); cell
SAINT-Plus (Bruker, 1998); data reduction: SAINT-Plus (Bruker, 1998); 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 CAMERON (Watkin et al., 1996); software used to prepare material for publication: WinGX (Farrugia, 1999).Fig. 1. ORTEP (Farrugia, 1997) view of the title compound, showing 50% probability ellipsoids and the atom numbering scheme. | |
Fig. 2. A unit cell packing of the title compound showing intermolecular interactions with dotted lines. H-atoms not involved in hydrogen bonding have been excluded. |
C18H11BrN4OS | F(000) = 1648 |
Mr = 411.28 | Dx = 1.725 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 3432 reflections |
a = 38.985 (17) Å | θ = 2.2–27.0° |
b = 5.764 (3) Å | µ = 2.74 mm−1 |
c = 14.925 (6) Å | T = 423 K |
β = 109.191 (13)° | Block, yellow |
V = 3167 (2) Å3 | 0.18 × 0.16 × 0.16 mm |
Z = 8 |
Bruker SMART APEX CCD detector diffractometer | 3432 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 2534 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.081 |
ω scans | θmax = 27.0°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 1998) | h = −44→49 |
Tmin = 0.638, Tmax = 0.668 | k = −7→7 |
8879 measured reflections | l = −16→19 |
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)] = 0.052 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.142 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0787P)2] where P = (Fo2 + 2Fc2)/3 |
3432 reflections | (Δ/σ)max < 0.001 |
226 parameters | Δρmax = 1.10 e Å−3 |
0 restraints | Δρmin = −1.02 e Å−3 |
C18H11BrN4OS | V = 3167 (2) Å3 |
Mr = 411.28 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 38.985 (17) Å | µ = 2.74 mm−1 |
b = 5.764 (3) Å | T = 423 K |
c = 14.925 (6) Å | 0.18 × 0.16 × 0.16 mm |
β = 109.191 (13)° |
Bruker SMART APEX CCD detector diffractometer | 3432 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1998) | 2534 reflections with I > 2σ(I) |
Tmin = 0.638, Tmax = 0.668 | Rint = 0.081 |
8879 measured reflections |
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.142 | H-atom parameters constrained |
S = 1.02 | Δρmax = 1.10 e Å−3 |
3432 reflections | Δρmin = −1.02 e Å−3 |
226 parameters |
Experimental. The compound was synthesized by following the procedure given in Lamani et al., (2009) |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 | ||
C1 | 0.14779 (11) | 0.5054 (7) | 0.4239 (3) | 0.0178 (8) | |
H1 | 0.1636 | 0.3813 | 0.4453 | 0.021* | |
C2 | 0.11246 (11) | 0.4910 (8) | 0.4268 (3) | 0.0213 (9) | |
H2 | 0.1048 | 0.3593 | 0.4507 | 0.026* | |
C3 | 0.08923 (11) | 0.6744 (7) | 0.3938 (3) | 0.0193 (9) | |
C4 | 0.10031 (12) | 0.8734 (7) | 0.3593 (3) | 0.0222 (9) | |
H4 | 0.0844 | 0.9972 | 0.3382 | 0.027* | |
C5 | 0.13517 (11) | 0.8857 (7) | 0.3567 (3) | 0.0200 (9) | |
H5 | 0.1426 | 1.0183 | 0.3327 | 0.024* | |
C6 | 0.15970 (11) | 0.7034 (7) | 0.3892 (3) | 0.0163 (8) | |
C7 | 0.19675 (11) | 0.7159 (7) | 0.3855 (3) | 0.0165 (8) | |
C8 | 0.21618 (11) | 0.9130 (7) | 0.3817 (3) | 0.0175 (8) | |
H8 | 0.2091 | 1.0667 | 0.3831 | 0.021* | |
C9 | 0.24700 (11) | 0.5928 (7) | 0.3759 (3) | 0.0166 (8) | |
C10 | 0.30080 (11) | 0.7731 (7) | 0.3592 (3) | 0.0178 (8) | |
C11 | 0.33397 (10) | 0.8402 (7) | 0.3361 (3) | 0.0168 (8) | |
H11A | 0.3421 | 0.9897 | 0.3651 | 0.020* | |
H11B | 0.3269 | 0.8616 | 0.2679 | 0.020* | |
C12 | 0.36595 (11) | 0.6779 (7) | 0.3653 (3) | 0.0178 (8) | |
C13 | 0.40073 (11) | 0.7153 (7) | 0.3545 (3) | 0.0162 (8) | |
C14 | 0.41996 (11) | 0.5140 (7) | 0.3897 (3) | 0.0187 (9) | |
C15 | 0.45543 (11) | 0.4746 (8) | 0.3946 (3) | 0.0212 (9) | |
H15 | 0.4677 | 0.3387 | 0.4197 | 0.025* | |
C16 | 0.47149 (12) | 0.6516 (8) | 0.3594 (3) | 0.0236 (9) | |
H16 | 0.4953 | 0.6341 | 0.3602 | 0.028* | |
C17 | 0.45273 (11) | 0.8557 (8) | 0.3228 (3) | 0.0216 (9) | |
H17 | 0.4643 | 0.9701 | 0.2994 | 0.026* | |
C18 | 0.41745 (12) | 0.8920 (8) | 0.3207 (3) | 0.0207 (9) | |
H18 | 0.4053 | 1.0295 | 0.2974 | 0.025* | |
Br1 | 0.040967 (11) | 0.65163 (8) | 0.39690 (3) | 0.02724 (18) | |
N1 | 0.21625 (9) | 0.5149 (6) | 0.3825 (2) | 0.0171 (7) | |
N2 | 0.24852 (9) | 0.8310 (6) | 0.3753 (2) | 0.0172 (7) | |
N3 | 0.27848 (9) | 0.9330 (6) | 0.3650 (2) | 0.0198 (7) | |
N4 | 0.36389 (9) | 0.4744 (6) | 0.4012 (2) | 0.0210 (8) | |
O1 | 0.39822 (8) | 0.3642 (5) | 0.4181 (2) | 0.0221 (7) | |
S1 | 0.28738 (3) | 0.48552 (18) | 0.36718 (7) | 0.0188 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0170 (19) | 0.009 (2) | 0.027 (2) | 0.0004 (16) | 0.0056 (16) | 0.0014 (15) |
C2 | 0.022 (2) | 0.019 (2) | 0.024 (2) | −0.0042 (18) | 0.0089 (17) | 0.0014 (17) |
C3 | 0.0144 (19) | 0.022 (2) | 0.0217 (19) | −0.0019 (17) | 0.0057 (16) | −0.0048 (16) |
C4 | 0.022 (2) | 0.016 (2) | 0.027 (2) | 0.0043 (18) | 0.0051 (18) | −0.0010 (16) |
C5 | 0.020 (2) | 0.015 (2) | 0.027 (2) | −0.0028 (17) | 0.0088 (17) | −0.0008 (16) |
C6 | 0.0138 (19) | 0.015 (2) | 0.0197 (19) | 0.0023 (16) | 0.0050 (15) | −0.0014 (15) |
C7 | 0.0150 (19) | 0.015 (2) | 0.0200 (19) | −0.0008 (16) | 0.0056 (16) | 0.0012 (15) |
C8 | 0.0155 (19) | 0.013 (2) | 0.025 (2) | 0.0029 (16) | 0.0085 (17) | −0.0007 (15) |
C9 | 0.017 (2) | 0.012 (2) | 0.0201 (19) | −0.0007 (16) | 0.0043 (16) | 0.0005 (14) |
C10 | 0.016 (2) | 0.013 (2) | 0.022 (2) | −0.0030 (17) | 0.0033 (16) | 0.0018 (16) |
C11 | 0.0127 (19) | 0.014 (2) | 0.024 (2) | −0.0023 (16) | 0.0063 (16) | 0.0041 (16) |
C12 | 0.017 (2) | 0.011 (2) | 0.0223 (19) | −0.0011 (16) | 0.0028 (16) | −0.0012 (15) |
C13 | 0.016 (2) | 0.011 (2) | 0.0196 (19) | 0.0012 (16) | 0.0028 (16) | 0.0006 (14) |
C14 | 0.018 (2) | 0.012 (2) | 0.026 (2) | 0.0009 (16) | 0.0072 (16) | 0.0017 (16) |
C15 | 0.017 (2) | 0.014 (2) | 0.030 (2) | 0.0055 (17) | 0.0052 (17) | −0.0019 (17) |
C16 | 0.018 (2) | 0.025 (3) | 0.027 (2) | −0.0016 (19) | 0.0060 (17) | −0.0013 (18) |
C17 | 0.019 (2) | 0.020 (2) | 0.027 (2) | −0.0024 (18) | 0.0091 (17) | 0.0020 (17) |
C18 | 0.021 (2) | 0.016 (2) | 0.024 (2) | −0.0013 (17) | 0.0063 (17) | 0.0019 (16) |
Br1 | 0.0161 (2) | 0.0308 (3) | 0.0357 (3) | −0.00248 (19) | 0.00975 (18) | −0.00722 (19) |
N1 | 0.0158 (16) | 0.0112 (18) | 0.0244 (17) | 0.0023 (14) | 0.0066 (14) | −0.0005 (13) |
N2 | 0.0159 (17) | 0.0112 (18) | 0.0254 (17) | −0.0007 (14) | 0.0082 (14) | −0.0012 (13) |
N3 | 0.0128 (16) | 0.0151 (19) | 0.0324 (19) | −0.0055 (14) | 0.0089 (15) | −0.0014 (15) |
N4 | 0.0151 (17) | 0.018 (2) | 0.0303 (19) | 0.0007 (15) | 0.0085 (14) | 0.0026 (14) |
O1 | 0.0177 (15) | 0.0107 (15) | 0.0403 (17) | 0.0047 (12) | 0.0127 (13) | 0.0085 (12) |
S1 | 0.0156 (5) | 0.0106 (5) | 0.0308 (5) | −0.0009 (4) | 0.0085 (4) | −0.0002 (4) |
C1—C6 | 1.393 (6) | C10—C11 | 1.495 (5) |
C1—C2 | 1.395 (6) | C10—S1 | 1.754 (4) |
C1—H1 | 0.9300 | C11—C12 | 1.504 (5) |
C2—C3 | 1.374 (6) | C11—H11A | 0.9700 |
C2—H2 | 0.9300 | C11—H11B | 0.9700 |
C3—C4 | 1.383 (6) | C12—N4 | 1.303 (5) |
C3—Br1 | 1.902 (4) | C12—C13 | 1.433 (6) |
C4—C5 | 1.374 (6) | C13—C14 | 1.387 (5) |
C4—H4 | 0.9300 | C13—C18 | 1.390 (6) |
C5—C6 | 1.396 (6) | C14—O1 | 1.371 (5) |
C5—H5 | 0.9300 | C14—C15 | 1.379 (6) |
C6—C7 | 1.465 (5) | C15—C16 | 1.387 (6) |
C7—C8 | 1.377 (6) | C15—H15 | 0.9300 |
C7—N1 | 1.395 (5) | C16—C17 | 1.398 (6) |
C8—N2 | 1.379 (5) | C16—H16 | 0.9300 |
C8—H8 | 0.9300 | C17—C18 | 1.381 (6) |
C9—N1 | 1.314 (5) | C17—H17 | 0.9300 |
C9—N2 | 1.374 (5) | C18—H18 | 0.9300 |
C9—S1 | 1.736 (4) | N2—N3 | 1.360 (5) |
C10—N3 | 1.290 (5) | N4—O1 | 1.427 (4) |
C6—C1—C2 | 120.9 (4) | C10—C11—H11B | 107.8 |
C6—C1—H1 | 119.6 | C12—C11—H11B | 107.8 |
C2—C1—H1 | 119.6 | H11A—C11—H11B | 107.1 |
C3—C2—C1 | 119.0 (4) | N4—C12—C13 | 111.7 (4) |
C3—C2—H2 | 120.5 | N4—C12—C11 | 121.5 (4) |
C1—C2—H2 | 120.5 | C13—C12—C11 | 126.7 (4) |
C2—C3—C4 | 121.5 (4) | C14—C13—C18 | 119.4 (4) |
C2—C3—Br1 | 118.6 (3) | C14—C13—C12 | 104.2 (3) |
C4—C3—Br1 | 119.9 (3) | C18—C13—C12 | 136.4 (4) |
C5—C4—C3 | 119.1 (4) | O1—C14—C15 | 126.2 (4) |
C5—C4—H4 | 120.5 | O1—C14—C13 | 109.4 (3) |
C3—C4—H4 | 120.5 | C15—C14—C13 | 124.4 (4) |
C4—C5—C6 | 121.5 (4) | C14—C15—C16 | 115.4 (4) |
C4—C5—H5 | 119.3 | C14—C15—H15 | 122.3 |
C6—C5—H5 | 119.3 | C16—C15—H15 | 122.3 |
C1—C6—C5 | 118.1 (4) | C15—C16—C17 | 121.6 (4) |
C1—C6—C7 | 120.5 (4) | C15—C16—H16 | 119.2 |
C5—C6—C7 | 121.4 (4) | C17—C16—H16 | 119.2 |
C8—C7—N1 | 111.8 (4) | C18—C17—C16 | 121.7 (4) |
C8—C7—C6 | 127.2 (4) | C18—C17—H17 | 119.2 |
N1—C7—C6 | 121.0 (4) | C16—C17—H17 | 119.2 |
C7—C8—N2 | 104.4 (4) | C17—C18—C13 | 117.6 (4) |
C7—C8—H8 | 127.8 | C17—C18—H18 | 121.2 |
N2—C8—H8 | 127.8 | C13—C18—H18 | 121.2 |
N1—C9—N2 | 112.6 (4) | C9—N1—C7 | 103.8 (3) |
N1—C9—S1 | 139.1 (3) | N3—N2—C9 | 118.2 (3) |
N2—C9—S1 | 108.3 (3) | N3—N2—C8 | 134.3 (4) |
N3—C10—C11 | 119.0 (4) | C9—N2—C8 | 107.4 (3) |
N3—C10—S1 | 116.6 (3) | C10—N3—N2 | 108.8 (3) |
C11—C10—S1 | 124.1 (3) | C12—N4—O1 | 107.0 (3) |
C10—C11—C12 | 118.0 (3) | C14—O1—N4 | 107.7 (3) |
C10—C11—H11A | 107.8 | C9—S1—C10 | 88.1 (2) |
C12—C11—H11A | 107.8 | ||
C6—C1—C2—C3 | 0.8 (6) | C13—C14—C15—C16 | −1.3 (6) |
C1—C2—C3—C4 | −1.0 (6) | C14—C15—C16—C17 | 0.7 (6) |
C1—C2—C3—Br1 | 179.3 (3) | C15—C16—C17—C18 | 0.6 (6) |
C2—C3—C4—C5 | 1.1 (6) | C16—C17—C18—C13 | −1.3 (6) |
Br1—C3—C4—C5 | −179.3 (3) | C14—C13—C18—C17 | 0.8 (6) |
C3—C4—C5—C6 | −0.9 (6) | C12—C13—C18—C17 | −179.8 (4) |
C2—C1—C6—C5 | −0.7 (6) | N2—C9—N1—C7 | 0.5 (4) |
C2—C1—C6—C7 | −179.4 (3) | S1—C9—N1—C7 | −179.3 (4) |
C4—C5—C6—C1 | 0.7 (6) | C8—C7—N1—C9 | −0.6 (4) |
C4—C5—C6—C7 | 179.4 (4) | C6—C7—N1—C9 | 177.6 (3) |
C1—C6—C7—C8 | −158.6 (4) | N1—C9—N2—N3 | −177.5 (3) |
C5—C6—C7—C8 | 22.8 (6) | S1—C9—N2—N3 | 2.4 (4) |
C1—C6—C7—N1 | 23.5 (5) | N1—C9—N2—C8 | −0.2 (4) |
C5—C6—C7—N1 | −155.2 (4) | S1—C9—N2—C8 | 179.7 (3) |
N1—C7—C8—N2 | 0.5 (4) | C7—C8—N2—N3 | 176.5 (4) |
C6—C7—C8—N2 | −177.6 (4) | C7—C8—N2—C9 | −0.2 (4) |
N3—C10—C11—C12 | 156.9 (4) | C11—C10—N3—N2 | 172.8 (3) |
S1—C10—C11—C12 | −30.0 (5) | S1—C10—N3—N2 | −0.8 (4) |
C10—C11—C12—N4 | 6.7 (6) | C9—N2—N3—C10 | −1.1 (5) |
C10—C11—C12—C13 | −176.4 (4) | C8—N2—N3—C10 | −177.5 (4) |
N4—C12—C13—C14 | −1.2 (4) | C13—C12—N4—O1 | 0.9 (4) |
C11—C12—C13—C14 | −178.4 (4) | C11—C12—N4—O1 | 178.3 (3) |
N4—C12—C13—C18 | 179.3 (4) | C15—C14—O1—N4 | 179.5 (4) |
C11—C12—C13—C18 | 2.2 (7) | C13—C14—O1—N4 | −0.5 (4) |
C18—C13—C14—O1 | −179.4 (3) | C12—N4—O1—C14 | −0.3 (4) |
C12—C13—C14—O1 | 1.0 (4) | N1—C9—S1—C10 | 177.7 (5) |
C18—C13—C14—C15 | 0.5 (6) | N2—C9—S1—C10 | −2.1 (3) |
C12—C13—C14—C15 | −179.0 (4) | N3—C10—S1—C9 | 1.8 (3) |
O1—C14—C15—C16 | 178.7 (4) | C11—C10—S1—C9 | −171.5 (3) |
Cg4 and Cg5 are the centroids of the C1–C6 and C13–C18 rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2···O1i | 0.93 | 2.38 | 3.219 (6) | 150 |
C8—H8···N1ii | 0.93 | 2.60 | 3.469 (6) | 156 |
C11—H11B···N1iii | 0.97 | 2.48 | 3.358 (6) | 150 |
C4—H4···Cg5iii | 0.93 | 2.96 | 3.554 (5) | 123 |
C18—H18···Cg4iii | 0.93 | 2.83 | 3.496 (5) | 130 |
Symmetry codes: (i) −x+1/2, −y+1/2, −z+1; (ii) x, y+1, z; (iii) −x+1/2, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C18H11BrN4OS |
Mr | 411.28 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 423 |
a, b, c (Å) | 38.985 (17), 5.764 (3), 14.925 (6) |
β (°) | 109.191 (13) |
V (Å3) | 3167 (2) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 2.74 |
Crystal size (mm) | 0.18 × 0.16 × 0.16 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD detector |
Absorption correction | Multi-scan (SADABS; Bruker, 1998) |
Tmin, Tmax | 0.638, 0.668 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8879, 3432, 2534 |
Rint | 0.081 |
(sin θ/λ)max (Å−1) | 0.639 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.052, 0.142, 1.02 |
No. of reflections | 3432 |
No. of parameters | 226 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.10, −1.02 |
Computer programs: SMART (Bruker, 1998), SAINT-Plus (Bruker, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and CAMERON (Watkin et al., 1996), WinGX (Farrugia, 1999).
Cg4 and Cg5 are the centroids of the C1–C6 and C13–C18 rings, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2···O1i | 0.93 | 2.38 | 3.219 (6) | 150 |
C8—H8···N1ii | 0.93 | 2.60 | 3.469 (6) | 156 |
C11—H11B···N1iii | 0.97 | 2.48 | 3.358 (6) | 150 |
C4—H4···Cg5iii | 0.93 | 2.96 | 3.554 (5) | 123 |
C18—H18···Cg4iii | 0.93 | 2.83 | 3.496 (5) | 130 |
Symmetry codes: (i) −x+1/2, −y+1/2, −z+1; (ii) x, y+1, z; (iii) −x+1/2, y+1/2, −z+1/2. |
Acknowledgements
NSB is thankful to the University Grants Commission (UGC), India, for financial assistance and the Department of Science and Technology, (DST), India, for the data collection facility under the IRHPA–DST program.
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.
Benzisoxazole derivatives are known to possess important biological activities (Priya et al., 2005). In view of increasing importance of the heterocycles in pharmaceutical and biological fields, it was considered of interest to synthesize some new chemical entities incorporating two active pharmacophores in a single molecular frame work and to evaluate their biological activities. In the title compound (Fig. 1), the fused imidazothiadiazole ring system is linked to a benzisoxazole and a bromophenyl moieties. The imidazothiadiazole (S1/N1–N3/C7–C10) and benzisoxazole (O1/N4/C12–C18) rings are individually planar similar to those reported earlier (Sun & Zhang, 2009) with maximum deviations 0.025 (3) Å for N2 and 0.015 (4) Å for C17, respectively. The mean-plane of benzisoxazole makes a dihedral angle of 23.51 (7)° with the mean-plane of the imidazothiadiazole ring. The planes of the imidazothiadiazole and bromophenyl rings are inclined at an angle 27.34 (3)° with each other. The differences in bond lengths S1—C9 (1.734 (5) Å) and S1—C10 (1.757 (5) Å) indicate that the resonance effect caused by the imidazole ring is stronger than that caused by the thiadiazole ring. In the crystal structure, intermolecular interactions C8—H8···N1 result in chains of molecules along the c-axis and C11—H11B···N1 interactions result in chains of molecules along the b-axis. Moreover, C2—H2···O1 interactions result in centrosymmetric head-to-head dimers corresponding to R22(24) graph set motif (Bernstein et al., 1995) (Fig. 2). The molecular packing is further stabilized by π-π stacking interactions between imidazo rings (Cg3) with the shortest centroid–centroid distance 3.492 (3) Å. In addition, π-ring interactions of the type C—H···Cg (Cg being the centroids of rings C1–C6 and C13–C18) are also observed in the crystal structure; details have been provided in Table 1.