3-{[5-(4-Bromo­phen­yl)imidazo[2,1-b][1,3,4]thia­diazol-2-yl]meth­yl}-1,2-benzoxazole

Afshan Banu; Mohamed Ziaulla; Noor Shahina Begum; Ravi S Lamani; I M Khazi

doi:10.1107/S1600536810052232

. 2010 Dec 18;67(Pt 1):o154. doi: 10.1107/S1600536810052232

3-{[5-(4-Bromophenyl)imidazo[2,1-b][1,3,4]thiadiazol-2-yl]methyl}-1,2-benzoxazole

Afshan Banu ^a, Mohamed Ziaulla ^a, Noor Shahina Begum ^a,^*, Ravi S Lamani ^b, I M Khazi ^b

PMCID: PMC3050133 PMID: 21522661

Abstract

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 R ₂ ²(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

C₁₈H₁₁BrN₄OS
M _r = 411.28
Monoclinic,
a = 38.985 (17) Å
b = 5.764 (3) Å
c = 14.925 (6) Å
β = 109.191 (13)°
V = 3167 (2) Å³
Z = 8
Mo Kα radiation
μ = 2.74 mm⁻¹
T = 423 K
0.18 × 0.16 × 0.16 mm

Data collection

Bruker SMART APEX CCD detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.638, T _max = 0.668
8879 measured reflections
3432 independent reflections
2534 reflections with I > 2σ(I)
R _int = 0.081

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.142
S = 1.02
3432 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 1.10 e Å⁻³
Δρ_min = −1.02 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: 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 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810052232/pv2359sup1.cif

e-67-0o154-sup1.cif^{(19.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810052232/pv2359Isup2.hkl

e-67-0o154-Isup2.hkl^{(165KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

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

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

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.

supplementary crystallographic information

Comment

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.

Experimental

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.