3-{[6-(4-Chloro­phen­yl)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/S1600536811004582

. 2011 Feb 12;67(Pt 3):o617–o618. doi: 10.1107/S1600536811004582

3-{[6-(4-Chlorophenyl)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: PMC3052169 PMID: 21522374

Abstract

In the title compound, C₁₈H₁₁ClN₄OS, the benzisoxazole and imidazothiadiazole rings are inclined at an angle of 23.81 (7)° with respect to each other. The imidazothiadiazole and chlorophenyl rings make a dihedral angle of 27.34 (3)°. In the crystal, intermolecular C—H⋯N interactions generate a chain along the c axis and C—H⋯O interactions form centrosymmetric dimers resulting in an R ₂ ²(26) graph-set motif. Moreover, the C—H⋯N and S⋯N [3.206 (4) Å] interactions links the molecules into R(7) ring motifs. The packing is further stabilized by π–π stacking interactions between the thiadiazole rings with a shortest centroid–centroid distance of 3.497 (3) Å. In addition, C—H⋯π interactions are observed in the crystal structure

Related literature

For the preparation of the title compound see: Lamani et al. (2009 ▶). For the biological activity of benzisoxazole derivatives, see: Priya et al. (2005 ▶). For the use of five-membered heterocyclic ring 1,3,4-thiadiazoles in the design of compounds, see: Katritzky (1984) ▶; Diamond & Sevrain (2003a ▶,b ▶); Nakao et al. (2002a ▶,b ▶). For related structures, see: Sun & Zhang (2009 ▶). For hydrogen-bond motifs, see: Bernstein et al. 1995 ▶)

Experimental

Crystal data

C₁₈H₁₁ClN₄OS
M _r = 366.83
Monoclinic,
a = 38.419 (7) Å
b = 5.7761 (10) Å
c = 14.772 (3) Å
β = 108.004 (5)°
V = 3117.5 (10) Å³
Z = 8
Mo Kα radiation
μ = 0.39 mm⁻¹
T = 123 K
0.18 × 0.16 × 0.16 mm

Data collection

Bruker SMART APEX CCD detector diffractometer
Absorption correction: multi-scan Bruker Smart Apex T _min = 0.933, T _max = 0.940
8822 measured reflections
3379 independent reflections
2587 reflections with I > 2σ(I)
R _int = 0.051

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.185
S = 1.31
3379 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 0.74 e Å⁻³
Δρ_min = −0.58 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/S1600536811004582/gw2098sup1.cif

e-67-0o617-sup1.cif^{(19.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811004582/gw2098Isup2.hkl

e-67-0o617-Isup2.hkl^{(162.5KB, hkl)}

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

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

Cg1 and Cg2 are the centroids of the C7–C12 and C13–C18 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9⋯O1ⁱ	0.93	2.39	3.232 (4)	150
C2—H2B⋯N1ⁱⁱ	0.97	2.49	3.352 (4)	148
C5—H5⋯N1ⁱⁱⁱ	0.93	2.60	3.478 (4)	157
C17—H17⋯Cg1^iv	0.93	2.78	3.470 (4)	131
C11—H11⋯Cg2^iv	0.93	2.93	3.548 (4)	126

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

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

Imidazo[2,1-b][1,3,4]thiadiazole derivatives are reported to possess diverse pharmacological properties such as anticancer, antitubercular, antibacterial, antifungal, anticonvulsant, analgesic and antisecretory activities. Moreover, the are known to possess important biological activities (Priya et al., 2005) and are useful in different therapies. Amongst them, five membered heterocyclic ring 1,3,4-thiadiazoles find wide application in designing compounds possessing useful properties (Katritzky et al., 1984; Diamond & Sevrain, 2003a,b; Nakao et al., 2002a,b). Due to the increasing importance of these heterocycles in biological and pharmaceutical fields, new chemical entities were synthesized by incorporating active pharmacophores in a single molecular frame work so as to enhance their biological activities.In the title compound, the benzisoxazole (O1/N4/C3/C13–18) and imidazothiadiazole (S1/N1—N3/C1/C4—C6) rings are individually planar similar to those reported earlier (Sun & Zhang, 2009) with maximum deviations of 0.038 (3)Å for C1 and 0.016 (3)Å for C3 respectively. The mean planes of the benzisoxazole and imidazothiadiazole are inclined at an angle 23.81 (7)° with each other. The imidazothiadiazole and chlorophenyl rings make a dihedral angle of 27.34 (3)°. The thiadiazole moiety displays differences in the bond lengths between S1—C1/S1—C4 [1.756 (3)/1.736 (3)]. This can be attributed to the resonance effects of the imidazole ring which is stronger than that due to thiadiazole group. The crystal structure is stabilized by intermolecular C—H···N, C—H···O and S···N interactions. The C—H···N interaction generates chain like pattern along c axis. The C—H···O interaction forms centrosymmetric head-to-head dimers about inversion centers corresponding to R22(26) graph set motif (Bernstein et al., 1995). The C—H···N interaction along with S···N [3.206 (4) Å]interaction results in a ring motif with a graph set R(7). The molecular packing is further stabilized by π-π stacking interactions between thiadiazole rings (Cg3: centroid of S1/C1/N2/N3/C4) with the shortest centroid—centroid distance 3.497 (3) Å. In addition, π-ring interactions of the type C—H···Cg (Cg being the centroids of rings C7—C12 and C13—C18) are also observed in the crystal structure; details have been given in Table 1.

Experimental

The title compound was synthesized by following the procedure reported earlier (Lamani et al., 2009).