6-(4-Chloro­phen­yl)-2-isobutyl­imidazo[2,1-b][1,3,4]thia­diazole

Hoong-Kun Fun; Madhukar Hemamalini; D Jagadeesh Prasad; G K Nagaraja; V V Anitha

doi:10.1107/S1600536810052621

. 2010 Dec 24;67(Pt 1):o207. doi: 10.1107/S1600536810052621

6-(4-Chlorophenyl)-2-isobutylimidazo[2,1-b][1,3,4]thiadiazole

Hoong-Kun Fun ^a,^*,^‡, Madhukar Hemamalini ^a, D Jagadeesh Prasad ^b, G K Nagaraja ^b, V V Anitha ^b

PMCID: PMC3050343 PMID: 21522707

Abstract

In the title compound, C₁₄H₁₄ClN₃S, the imidazo[2,1-b][1,3,4]thiadiazole system is essentially planar, with a maximum deviation of 0.006 (2) Å. The dihedral angle between the imidazo[2,1-b][1,3,4]thiadiazole and chlorophenyl rings is 5.07 (8)°. In the crystal, there are no classical hydrogen bonds but stabilization is provided by weak π–π [centroid–centroid distance = 3.5697 (11) Å] and C—H⋯π interactions.

Related literature

For applications of imidazo [2,1-b]-1,3,4-thiadiazole derivatives, see: Terzioglu & Gursoy (2003 ▶); Kolavi et al. (2006 ▶); Gadad et al. (2000 ▶); Andotra et al. (1997 ▶); Khazi et al. (1996 ▶); Andreani et al. (1982 ▶,1987 ▶,1991 ▶); Eberle & Robert (1977 ▶).

Experimental

Crystal data

C₁₄H₁₄ClN₃S
M _r = 291.79
Monoclinic,
a = 5.7552 (1) Å
b = 26.4052 (5) Å
c = 9.7662 (2) Å
β = 101.388 (1)°
V = 1454.92 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.40 mm⁻¹
T = 296 K
0.47 × 0.31 × 0.28 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009) ▶ T _min = 0.835, T _max = 0.897
12320 measured reflections
3353 independent reflections
2646 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.135
S = 1.05
3353 reflections
172 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810052621/ng5089sup1.cif

e-67-0o207-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810052621/ng5089Isup2.hkl

e-67-0o207-Isup2.hkl^{(164.5KB, hkl)}

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

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

Cg3 is the centroid of the C1–C6 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H11B⋯Cg3ⁱ	0.97	2.70	3.544 (2)	145

Open in a new tab

Symmetry code: (i) Inline graphic .

Acknowledgments

HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

Imidazo [2,1-b]-1,3,4-thiadiazole derivatives are found to be biologically active compounds possessing anticancer (Terzioglu, 2003), antitubercular (Kolavi et al., 2006), antibacterial (Gadad et al., 2000), antifungal (Andotra et al., 1997), anticonvulsant, analgesic (Khazi et al., 1996), anti-inflammatory (Andreani et al., 1982), diuretic (Andreani et al., 1991) and herbicidal activities (Andreani et al., 1991). Moreover 1,3,4-thiadiazoles have many interesting biological activities, for example, 2-amino-5-(trifluoromethylphenyl alkyl)-1,3,4 thidadiazoles are used in the treatment of insomnia and anxiety (Eberle & Robert, 1977).

The asymmetric unit of the title compound is shown in Fig. 1. The imidazo[2,1-b] [1,3,4]thiadiazole (S1/N1–N3/C7–C10) ring is essentially planar, with a maximum deviation of 0.006 (2) Å for atom N3. The dihedral angle between the imidazo[2,1-b][1,3,4]thiadiazole (S1/N1–N3/C7–C10) ring and the chlorophenyl ring (C1–C6) is 5.07 (8)°.

In the crystal structure (Fig. 2), there are no classical hydrogen bonds but stabilization is provided by weak π–π interactions between the imidazole rings (N1–N2/C7–C8/C10) [centroid-to-centroid (2-x, -y, 2-z) distance = 3.5697 (11) Å]. Furthermore, the crystal structure is stabilized by C—H···π interactions (Table 1), involving the (C1–C6)(centroid Cg3) ring.

Experimental

5-Isobutyl-1,3,4-thiadiazole-2-amine( 1 equivalent) and 4-chlorophenacyl bromide (1 equivalent) are refluxed with ethanol for 4 hrs. The solvent was then distilled off and the reaction mass was poured onto crushed ice. The resulting solid, 6-(4-chlorophenyl)-2-isobutylimidazo[2,1-b] [1,3,4]thiadiazole, that separated out was filtered and dried. The compound was recrystallized using ethanol and DMF mixture. M.pt. 121–126 °C.