6-(4-Chloro­phen­yl)-3-methyl­imidazo[2,1-b]thia­zole

Bunev, A.S.; Sukhonosova, E.V.; Statsyuk, V.E.; Ostapenko, G.I.; Khrustalev, V.N.

doi:10.1107/S1600536813028833

organic compounds

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ISSN: 2056-9890

Volume 69| Part 11| November 2013| Page o1701

doi:10.1107/S1600536813028833

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6-(4-Chlorophenyl)-3-methylimidazo[2,1-b]thiazole

Alexander S. Bunev,^a ^* Elena V. Sukhonosova,^b Vladimir E. Statsyuk,^a Gennady I. Ostapenko ^a and Victor N. Khrustalev ^c

^aDepartment of Chemistry and Chemical Technology, Togliatti State University, 14 Belorusskaya St, Togliatti 445667, Russian Federation, ^bDepartment of Organic, Bioorganic and Medicinal Chemistry, Samara State University, 1 Academician Pavlov St, Samara 443011, Russian Federation, and ^cX-Ray Structural Centre, A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, B-334, Moscow 119991, Russian Federation
^*Correspondence e-mail: a.s.bunev@gmail.com

(Received 17 October 2013; accepted 20 October 2013; online 26 October 2013)

In the title compound, C₁₂H₉ClN₂S, the imidazo[2,1-b]thiazole fragment is planar (r.m.s. deviation = 0.003 Å), and the benzene ring is twisted slightly [by 5.65 (6)°] relative to this moiety. In the crystal, molecules are linked by π–π stacking interactions into columns along [010]. The molecules within the columns are arranged alternatively by their planar rotation of 180°. Thus, in the columns, there are the two types of π–π stacking interactions, namely, (i) between two imidazo[2,1-b]thiazole fragments [interplanar distance = 3.351 (2) Å] and (ii) between an imidazo[2,1-b]thiazole fragment and the phenyl ring [interplanar distance = 3.410 (5) Å]. There are no short contacts between the columns.

CCDC reference: 967485

Related literature

For the synthesis and properties of related compounds containing an imidazo[2,1-b]thiazole moiety, see: Raeymaekers et al. (1966 ); Metaye et al. (1992 ); Carpenter et al. (2003 ); Milne et al. (2007 ); Scribner et al. (2008 ); Chorell et al. (2010 ); Guzeldemirci & Kucukbasmaci (2010 ); Budriesi et al. (2011 ); Yousefi et al. (2011 ).

Experimental

Crystal data

C₁₂H₉ClN₂S
M_r = 248.73
Triclinic, $[P \overline 1]$
a = 7.0624 (5) Å
b = 7.7132 (5) Å
c = 10.3460 (7) Å
α = 93.353 (1)°
β = 90.107 (1)°
γ = 98.832 (1)°
V = 555.92 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.50 mm⁻¹
T = 120 K
0.30 × 0.20 × 0.20 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ) T_min = 0.864, T_max = 0.906
6927 measured reflections
2963 independent reflections
2306 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.038
wR(F²) = 0.093
S = 1.05
2963 reflections
146 parameters
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ); cell refinement: SAINT (Bruker, 2001 ); 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.

Supporting information

CCDC reference: 967485

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536813028833/rk2417sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813028833/rk2417Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536813028833/rk2417Isup3.cml

checkCIF report

Comment top

Many natural products and biologically active compounds containing imidazo[2,1-b]thiazole moieties have been discovered and synthesized so far (Metaye et al., 1992; Guzeldemirci & Kucukbasmaci, 2010; Budriesi et al., 2011). As some typical examples, anthelmintics tetramisole (Raeymaekers et al., 1966), thieno(3,2-d)pyrimidinone (Carpenter et al., 2003), 5,6-diarylimidazo[2,1-b](1,3)thiazoles (Scribner et al., 2008), C-2 aryl-substituted pilicides (Chorell et al., 2010), and ¹¹C-labeled imidazo[2,1-b]benzothiazoles (Yousefi et al., 2011) all showed effective biological and medicinal activity. Milne and co-authors (Milne et al., 2007) described the identification and characterization of a molecule bearing imidazo[2,1-b]thiazole as an activator of SIRT1, which was structurally unrelated to, and 1000-fold more potent than, resveratrol. And it can bind to the SIRT1 enzyme-peptide substrate complex at an allosteric site amino terminal to the catalytic domain and lower the Michaelis constant for acetylated substrates.

In this work, a 6-(4-chlorophenyl)-3-methylimidazo[2,1-b]thiazole, C₁₂H₉ClN₂S, I, was prepared by the reaction of 4-methyl-2-aminothiazole with 2-bromo-1-(4-chlorophenyl)ethanone (Fig. 1), and its structure was unambiguously established by the X-ray diffraction study (Fig. 2).

The imidazo[2,1-b]thiazole fragment in I is planar (r.m.s. deviation is 0.003Å), and the phenyl ring is slightly twisted in relative to this fragment by 5.65 (6)°.

In the crystal, the molecules of I are linked by the intermolecular π···π-stacking interactions into columns along [010] (Fig. 3). The molecules within the columns are arranged alternatively by their planar rotation of 180° (Fig. 3). Thus, in the columns of I, there are the two types of π···π-stacking interactions, namely, (i) between two imidazo[2,1-b]thiazole fragments (the interplane distance is 3.351 (2)Å) and (ii) between imidazo[2,1-b]thiazole fragment and phenyl ring (the interplane distance is 3.410 (5)Å). There are no any short contacts between the columns (Fig. 4).

Related literature top

For the synthesis and properties of related compounds containing an imidazo[2,1-b]thiazole moiety, see: Raeymaekers et al. (1966); Metaye et al. (1992); Carpenter et al. (2003); Milne et al. (2007); Scribner et al. (2008); Chorell et al. (2010); Guzeldemirci & Kucukbasmaci (2010); Budriesi et al. (2011); Yousefi et al. (2011).

Experimental top

A mixture of 4-methyl-2-aminothiazole (5.0 g, 43.8 mmol) and 2-bromo-1-(4-chlorophenyl)ethanone (10.2 g, 43.8 mmol) was dissolved in acetone (40 mL). The reaction mixture was stirred for 24 h. The resulting precipitate was collected, suspended in 2N HCl (70 mL) and heated under reflux. The warm solution basified with 20% NH₄OH yielded the expected imidazo[2,1-b]thiazole after cooling upto room temperature. The residue crystallized from N,N-dimethylformamide. Yield is 78%. The single crystal of the product was obtained by slow crystallization from N,N-dimethylformamide. M.p. = 397-399 K. IR (KBr), ν/cm^-1: ¹H NMR (500 MHz, DMSO-d₆, 304 K): 2.43 (s, 3H, CH₃), 6.91 (s, 1H, H5), 7.46 (d, 2H, J = 8.55, H11,13), 7.87 (d, 2H, J = 8.55, H10,14), 8.31 (s, 1H, H2) . Anal. Calcd for C₁₂H₉ClN₂S: C, 57.95; H, 3.65. Found: C, 57.91; H, 3.59.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The reaction of 4-methyl-2-aminothiazole with 2-bromo-1-(4-chlorophenyl)ethanone.
	Fig. 2. Molecular structure of I with the atom numbering scheme. Displacement ellipsoids are presented at the 50% probability level. H atoms are depicted as small spheres of arbitrary radius.
	Fig. 3. The π···π-bonded column of I along [010].
	Fig. 4. The crystal packing of I along the b axis.

6-(4-Chlorophenyl)-3-methylimidazo[2,1-b]thiazole top

Crystal data top

C₁₂H₉ClN₂S	Z = 2
M_r = 248.73	F(000) = 256
Triclinic, P1	D_x = 1.486 Mg m⁻³
Hall symbol: -P 1	Melting point = 397–399 K
a = 7.0624 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.7132 (5) Å	Cell parameters from 2226 reflections
c = 10.3460 (7) Å	θ = 2.7–30.6°
α = 93.353 (1)°	µ = 0.50 mm⁻¹
β = 90.107 (1)°	T = 120 K
γ = 98.832 (1)°	Prism, colourless
V = 555.92 (7) Å³	0.30 × 0.20 × 0.20 mm

Data collection top

Bruker APEXII CCD diffractometer	2963 independent reflections
Radiation source: fine-focus sealed tube	2306 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
ϕ and ω scans	θ_max = 29.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −9→9
T_min = 0.864, T_max = 0.906	k = −10→10
6927 measured reflections	l = −14→14

Refinement top

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.093	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0461P)² + 0.0291P] where P = (F_o² + 2F_c²)/3
2963 reflections	(Δ/σ)_max = 0.001
146 parameters	Δρ_max = 0.38 e Å⁻³
0 restraints	Δρ_min = −0.22 e Å⁻³

Crystal data top

C₁₂H₉ClN₂S	γ = 98.832 (1)°
M_r = 248.73	V = 555.92 (7) Å³
Triclinic, P1	Z = 2
a = 7.0624 (5) Å	Mo Kα radiation
b = 7.7132 (5) Å	µ = 0.50 mm⁻¹
c = 10.3460 (7) Å	T = 120 K
α = 93.353 (1)°	0.30 × 0.20 × 0.20 mm
β = 90.107 (1)°

Data collection top

Bruker APEXII CCD diffractometer	2963 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2003)	2306 reflections with I > 2σ(I)
T_min = 0.864, T_max = 0.906	R_int = 0.032
6927 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.038	0 restraints
wR(F²) = 0.093	H-atom parameters constrained
S = 1.05	Δρ_max = 0.38 e Å⁻³
2963 reflections	Δρ_min = −0.22 e Å⁻³
146 parameters

Special details top

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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.38211 (8)	0.73973 (6)	1.00250 (4)	0.04269 (15)
S1	0.13039 (6)	0.04797 (6)	0.19530 (4)	0.02548 (12)
C2	−0.1162 (2)	−0.0288 (2)	0.18876 (16)	0.0239 (3)
H2	−0.1768	−0.1011	0.1184	0.029*
C3	−0.2120 (2)	0.0238 (2)	0.29218 (15)	0.0203 (3)
N4	−0.08638 (17)	0.12958 (16)	0.37993 (12)	0.0180 (3)
C5	−0.0956 (2)	0.21865 (19)	0.49862 (14)	0.0189 (3)
H5	−0.2063	0.2255	0.5495	0.023*
C6	0.0896 (2)	0.29557 (19)	0.52765 (14)	0.0190 (3)
N7	0.21503 (18)	0.25589 (17)	0.42952 (12)	0.0204 (3)
C7A	0.1018 (2)	0.1576 (2)	0.34408 (15)	0.0201 (3)
C8	−0.4178 (2)	−0.0182 (2)	0.32472 (17)	0.0258 (3)
H8A	−0.4875	−0.0863	0.2518	0.039*
H8B	−0.4704	0.0911	0.3422	0.039*
H8C	−0.4314	−0.0873	0.4017	0.039*
C9	0.1606 (2)	0.40574 (19)	0.64315 (14)	0.0188 (3)
C10	0.0334 (2)	0.4576 (2)	0.73671 (15)	0.0230 (3)
H10	−0.1006	0.4220	0.7246	0.028*
C11	0.1012 (3)	0.5600 (2)	0.84631 (16)	0.0272 (4)
H11	0.0142	0.5955	0.9087	0.033*
C12	0.2971 (3)	0.6103 (2)	0.86436 (15)	0.0271 (4)
C13	0.4260 (2)	0.5626 (2)	0.77325 (16)	0.0265 (4)
H13	0.5598	0.5985	0.7860	0.032*
C14	0.3567 (2)	0.4617 (2)	0.66341 (15)	0.0222 (3)
H14	0.4445	0.4298	0.6002	0.027*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0636 (3)	0.0379 (3)	0.0254 (2)	0.0095 (2)	−0.0140 (2)	−0.01208 (19)
S1	0.0251 (2)	0.0306 (2)	0.0207 (2)	0.00669 (17)	0.00010 (15)	−0.00563 (16)
C2	0.0266 (8)	0.0227 (8)	0.0224 (8)	0.0048 (7)	−0.0059 (6)	−0.0019 (6)
C3	0.0214 (7)	0.0173 (7)	0.0225 (8)	0.0040 (6)	−0.0064 (6)	0.0014 (6)
N4	0.0190 (6)	0.0166 (6)	0.0190 (6)	0.0045 (5)	−0.0015 (5)	0.0008 (5)
C5	0.0220 (7)	0.0181 (7)	0.0172 (7)	0.0053 (6)	0.0011 (6)	0.0017 (6)
C6	0.0230 (8)	0.0173 (7)	0.0176 (7)	0.0054 (6)	0.0003 (6)	0.0019 (6)
N7	0.0199 (6)	0.0221 (6)	0.0191 (6)	0.0034 (5)	0.0004 (5)	−0.0007 (5)
C7A	0.0211 (7)	0.0215 (7)	0.0187 (7)	0.0064 (6)	0.0011 (6)	0.0007 (6)
C8	0.0212 (8)	0.0263 (8)	0.0292 (9)	0.0027 (7)	−0.0041 (6)	−0.0027 (7)
C9	0.0253 (8)	0.0142 (7)	0.0172 (7)	0.0028 (6)	−0.0018 (6)	0.0031 (6)
C10	0.0275 (8)	0.0190 (7)	0.0230 (8)	0.0049 (6)	0.0014 (6)	0.0027 (6)
C11	0.0417 (10)	0.0228 (8)	0.0192 (8)	0.0107 (7)	0.0030 (7)	0.0021 (6)
C12	0.0438 (10)	0.0193 (7)	0.0178 (7)	0.0047 (7)	−0.0072 (7)	−0.0019 (6)
C13	0.0321 (9)	0.0218 (8)	0.0249 (8)	0.0010 (7)	−0.0067 (7)	0.0027 (7)
C14	0.0262 (8)	0.0199 (7)	0.0200 (7)	0.0019 (6)	0.0000 (6)	0.0022 (6)

Geometric parameters (Å, º) top

Cl1—C12	1.7450 (17)	C8—H8A	0.9800
S1—C7A	1.7399 (16)	C8—H8B	0.9800
S1—C2	1.7512 (17)	C8—H8C	0.9800
C2—C3	1.343 (2)	C9—C14	1.397 (2)
C2—H2	0.9500	C9—C10	1.404 (2)
C3—N4	1.4018 (19)	C10—C11	1.384 (2)
C3—C8	1.483 (2)	C10—H10	0.9500
N4—C7A	1.3685 (19)	C11—C12	1.388 (2)
N4—C5	1.3782 (19)	C11—H11	0.9500
C5—C6	1.376 (2)	C12—C13	1.385 (2)
C5—H5	0.9500	C13—C14	1.383 (2)
C6—N7	1.3996 (18)	C13—H13	0.9500
C6—C9	1.466 (2)	C14—H14	0.9500
N7—C7A	1.315 (2)

C7A—S1—C2	89.68 (7)	H8A—C8—H8B	109.5
C3—C2—S1	113.96 (12)	C3—C8—H8C	109.5
C3—C2—H2	123.0	H8A—C8—H8C	109.5
S1—C2—H2	123.0	H8B—C8—H8C	109.5
C2—C3—N4	110.46 (14)	C14—C9—C10	118.13 (14)
C2—C3—C8	130.15 (15)	C14—C9—C6	120.96 (14)
N4—C3—C8	119.35 (13)	C10—C9—C6	120.91 (14)
C7A—N4—C5	106.48 (12)	C11—C10—C9	120.71 (16)
C7A—N4—C3	115.56 (13)	C11—C10—H10	119.6
C5—N4—C3	137.96 (13)	C9—C10—H10	119.6
C6—C5—N4	105.33 (12)	C10—C11—C12	119.54 (15)
C6—C5—H5	127.3	C10—C11—H11	120.2
N4—C5—H5	127.3	C12—C11—H11	120.2
C5—C6—N7	111.17 (13)	C13—C12—C11	121.06 (15)
C5—C6—C9	128.03 (14)	C13—C12—Cl1	119.50 (14)
N7—C6—C9	120.79 (14)	C11—C12—Cl1	119.43 (13)
C7A—N7—C6	103.37 (12)	C14—C13—C12	118.94 (16)
N7—C7A—N4	113.65 (13)	C14—C13—H13	120.5
N7—C7A—S1	136.01 (12)	C12—C13—H13	120.5
N4—C7A—S1	110.33 (11)	C13—C14—C9	121.60 (15)
C3—C8—H8A	109.5	C13—C14—H14	119.2
C3—C8—H8B	109.5	C9—C14—H14	119.2

C7A—S1—C2—C3	−0.51 (13)	C3—N4—C7A—S1	−0.54 (16)
S1—C2—C3—N4	0.30 (17)	C2—S1—C7A—N7	179.01 (17)
S1—C2—C3—C8	−177.40 (14)	C2—S1—C7A—N4	0.57 (12)
C2—C3—N4—C7A	0.17 (19)	C5—C6—C9—C14	174.39 (15)
C8—C3—N4—C7A	178.15 (13)	N7—C6—C9—C14	−5.4 (2)
C2—C3—N4—C5	−179.57 (16)	C5—C6—C9—C10	−5.4 (2)
C8—C3—N4—C5	−1.6 (3)	N7—C6—C9—C10	174.78 (14)
C7A—N4—C5—C6	−0.14 (16)	C14—C9—C10—C11	−0.6 (2)
C3—N4—C5—C6	179.61 (16)	C6—C9—C10—C11	179.28 (14)
N4—C5—C6—N7	−0.20 (17)	C9—C10—C11—C12	−0.7 (2)
N4—C5—C6—C9	−179.99 (14)	C10—C11—C12—C13	1.2 (2)
C5—C6—N7—C7A	0.46 (16)	C10—C11—C12—Cl1	179.89 (12)
C9—C6—N7—C7A	−179.73 (13)	C11—C12—C13—C14	−0.6 (2)
C6—N7—C7A—N4	−0.56 (17)	Cl1—C12—C13—C14	−179.23 (12)
C6—N7—C7A—S1	−178.95 (14)	C12—C13—C14—C9	−0.7 (2)
C5—N4—C7A—N7	0.46 (17)	C10—C9—C14—C13	1.2 (2)
C3—N4—C7A—N7	−179.35 (12)	C6—C9—C14—C13	−178.60 (14)
C5—N4—C7A—S1	179.27 (10)

Experimental details

Crystal data
Chemical formula	C₁₂H₉ClN₂S
M_r	248.73
Crystal system, space group	Triclinic, P1
Temperature (K)	120
a, b, c (Å)	7.0624 (5), 7.7132 (5), 10.3460 (7)
α, β, γ (°)	93.353 (1), 90.107 (1), 98.832 (1)
V (Å³)	555.92 (7)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.50
Crystal size (mm)	0.30 × 0.20 × 0.20

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2003)
T_min, T_max	0.864, 0.906
No. of measured, independent and observed [I > 2σ(I)] reflections	6927, 2963, 2306
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.682

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.038, 0.093, 1.05
No. of reflections	2963
No. of parameters	146
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.38, −0.22

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2001), SHELXTL (Sheldrick, 2008).

Acknowledgements

The authors are grateful to the Ministry of Education and Science of the Russian Federation (State program No. 3.1168.2011).

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