Ethyl 6-methyl­sulfanyl-2-phenyl-1H-imidazo[1,2-b]pyrazole-7-carboxyl­ate monohydrate

Teng-fei Shao; Gui-long Zhao; Jian-wu Wang

doi:10.1107/S1600536809010988

. 2009 Mar 31;65(Pt 4):o923. doi: 10.1107/S1600536809010988

Ethyl 6-methylsulfanyl-2-phenyl-1H-imidazo[1,2-b]pyrazole-7-carboxylate monohydrate

Teng-fei Shao ^a, Gui-long Zhao ^a, Jian-wu Wang ^a,^*

PMCID: PMC2968784 PMID: 21582625

Abstract

The title compound, C₁₅H₁₅N₃O₂S·H₂O, has been obtained in a search for new imidazo[1,2-b]pyrazole derivatives with better biological activity. The 1H-imidazo[1,2-b]pyrazole plane forms a dihedral angle of 16.90 (3)° with the benzene ring. π–π interactions are indicated by the short distance of 3.643 (2) Å between the centroids of the benzene and imidazole rings. The crystal structure also involves intermolecular O—H⋯N hydrogen bonds.

Related literature

For the biological activity of imidazo[1,2-b]pyrazole derivatives, see: Vanotti et al. (1994 ▶); Kinnamon et al. (2000 ▶); Li et al. (2005 ▶). For bond-length data, see: Allen et al., 1987 ▶.

Experimental

Crystal data

C₁₅H₁₅N₃O₂S·H₂O
M _r = 319.38
Orthorhombic,
a = 19.017 (2) Å
b = 5.4854 (7) Å
c = 15.2314 (18) Å
V = 1588.9 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 273 K
0.20 × 0.10 × 0.10 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.957, T _max = 0.978
8763 measured reflections
3326 independent reflections
1877 reflections with I > 2σ(I)
R _int = 0.051

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.094
S = 0.97
3326 reflections
207 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.14 e Å⁻³
Absolute structure: Flack (1983 ▶), 1442 Friedel pairs
Flack parameter: −0.01 (9)

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1999 ▶); 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.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809010988/hg2495sup1.cif

e-65-0o923-sup1.cif^{(19.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809010988/hg2495Isup2.hkl

e-65-0o923-Isup2.hkl^{(163.2KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3A⋯N3ⁱ	0.99 (6)	1.86 (6)	2.809 (4)	160 (5)

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

Imidazo[1,2-b]pyrazole derivatives have been reported to show various biological activities [Vanotti et al., 1994; Kinnamon et al., 2000], in continuation of our research interest in this field [Li et al., 2005], the new title compound has been synthesized in a search for new compounds with better biological activity, and its crystal structure was determined by X-ray diffraction method.

The title compound crystallizes as a monohydrate (Fig. 1), all bond lengths are normal and in a good agreement with those reported previously (Allen et al., 1987). Atoms S1/O1/O2/C12/C13/C14 lie in 1H-imidazo[1,2-b]pyrazole (C7—C11/N1/N2/N3) plane with maximum least squares plane deviation for C14 0.070 (3) Å. The 1H-imidazo[1,2-b]pyrazole plane forms dihedral angles of 16.90 (3)° with the benzene ring (C1—C6). π-π stacking interactions (Table 1) are present in the structure. The crystal structure involves intermolecular are O–H···N hydrogen bonds.

Experimental

A suspended solution in 30 ml of acetonitrile containing 5 mmol (1.01 g) of ethyl 5-amino-3-methylthio-1H-pyrazole-4-carboxylate, 5 mmol (1.00) of α-bromoacetophenone and 10 mmol (1.38 g) of sodium carbonate was refluxed for about 10 h until the starting materials were consumed completely, as indicated by TLC. On cooling, the solid was removed through filtration, and the filtrate was evaporated to afford a residue, which was dissolved in 30 ml of absolute ethanol, followed by the addition of several drops of concentrated hydrochloric acid. The resulting solution was then refluxed for about 3 h, and cooled to room temperature. The solution was then evaporated in vacuo to afford the crude product, which was purified by column chromatography using ethyl acetate/petroleum ether (1:5) to give 0.87 g of pure title compound. Crystals suitable for X-ray diffraction were obtained from slow evaporation of a solution of the title compound in dichloromethane/ethyl acetate/petroleum ether (1/2/1) at room temperature.