7-(2,4-Dichloro­phen­yl)-2-methyl­sulfanyl­pyrazolo[1,5-a]pyrimidine-3-carbonitrile

Li-rong Wen; Huai-yuan Xie; Shu-wen Wang

doi:10.1107/S1600536809014792

. 2009 Apr 25;65(Pt 5):o1116. doi: 10.1107/S1600536809014792

7-(2,4-Dichlorophenyl)-2-methylsulfanylpyrazolo[1,5-a]pyrimidine-3-carbonitrile

Li-rong Wen ^a,^*, Huai-yuan Xie ^a, Shu-wen Wang ^a

PMCID: PMC2977792 PMID: 21583928

Abstract

In the molecule of the title compound, C₁₄H₈Cl₂N₄S, all the ring atoms in the pyrazolopyrimidine system are almost coplanar, the largest deviation from the mean plane being 0.027 (2) Å for a C atom. The conformation of the methylsulfanyl group is antiperiplanar, with a torsion angle of −176.7 (2)°. A weak intermolecular C—H⋯N hydrogen bond and a Cl⋯N halogen bond [Cl⋯N = 3.196 (5) Å] with a nearly linear N⋯Cl—C angle [174.2 (1)°] link the molecules into a two-dimensional assembly. Face-to-face π–π stacking, with a centroid–centroid separation of 3.557 (2) Å and an angle of 7.1 (1)° between the two planes, completes the intermolecular interactions in the solid state.

Related literature

For the biological activity of pyrazolo[1,5-a]pyrimidine derivatives, see: Li et al. (1995 ▶). For applications of enaminones, see: El-Taweei et al. (2001 ▶); Hernandez et al. (2003 ▶); Olivera et al. (2000 ▶). For bond-length data, see: Allen et al. (1987 ▶). For Cl⋯N halogen bonds, see: Chu, et al. (2001 ▶); Lommerse et al. (1996 ▶); Ramasubbu et al. (1986 ▶).

Experimental

Crystal data

C₁₄H₈Cl₂N₄S
M _r = 335.20
Monoclinic,
a = 8.230 (2) Å
b = 14.656 (4) Å
c = 12.667 (4) Å
β = 108.460 (5)°
V = 1449.3 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.59 mm⁻¹
T = 293 K
0.32 × 0.26 × 0.22 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.814, T _max = 0.879
8252 measured reflections
2965 independent reflections
2181 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.095
S = 1.04
2965 reflections
191 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809014792/zl2192sup1.cif

e-65-o1116-sup1.cif^{(17.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809014792/zl2192Isup2.hkl

e-65-o1116-Isup2.hkl^{(145.5KB, 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
C8—H8⋯N4ⁱ	0.93	2.61	3.474 (3)	154

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Symmetry code: (i) Inline graphic .

Acknowledgments

We thank the Natural Science Foundation of Shandong Province (No. Y2006B11) for financial support.

supplementary crystallographic information

Comment

Pyrazolo[1,5-a]pyrimidine derivatives have been reported to show various biological activities such as antibacterial, insulin releasing, anti-inflammatory activities (Li et al., 1995). Enaminones have been widely used as building blocks in the synthesis of pyrazolo[1,5-a]pyrimidine derivatives (El-Taweei et al., 2001; Hernandez et al., 2003; Olivera et al., 2000). We report here the crystal structure of title compound (Fig.1), which was synthesized by reaction of 1-(2,4-dichlorophenyl)-3-dimethylamino-2-en-1-one and 3-methylsulfanyl-4-cyano-5-amino-1H-pyrazole in the presence of acetic acid.

The bond lengths and angles in this compound are within normal ranges (Allen, 2002). All the ring atoms in the pyrazolopyrimidine moiety are almost coplanar, the largest deviation from the mean plane being 0.027 (2)Å for atom C10. The dihedral angle between the pyrazolopyrimidine moiety and the benzene ring is 54.9 (5)°. The conformation of the methylsulfanyl moiety is antiperiplanar with a torsion angle C11—C12—S1—C13 of -176.7 (2)°.

In the crystal structure of the title compound, there are a weak intermolecular hydrogen bond of one phenyl hydrogen atom towards the nitrile N atom (C8—H8···N4, Table 1) and a nitrogen-chlorine donor-acceptor interaction (Chu, et al., 2001; Lommerse et al., 1996; Ramasubbu, et al., 1986) between the pyrimidinyl N atom and one of the chlorine atoms. The distance between Cl2 and N3 is 3.196 (5) Å which is definitively shorter than the sum of the corresponding van der Waals radii of Cl (1.75 Å) and N (1.55 Å). Moreover, this contact of N3 with Cl2 is nearly "head on" with N approaching Cl along the backside of C3—Cl2 with the N3···Cl2—C3 angle approximately linear 174.2 (1)° [symmetry code: -3/2 + x, 1/2 - y, -1/2 + z] (Fig. 2). These interactions loosly link the molecules into a two-dimensional assembly (Fig. 3). Face-to-face π-π stacking between the phenyl ring (C1—C6) and the pyrazol ring (C10—C12/N1/N2) in another molecule at 1/2+x, 3/2-y, 1/2+z complete the intermolecular interactions in the solid state. The centroid to centroid separation is 3.557 (2) Å and the angle between the two planes is 7.1 (1)°.

Experimental

A mixture of 1-(2,4-dichlorophenyl)-3-dimethylamino-2-en-1-one (2 mmol) and 3-methylsulfanyl-4-cyano-5-amino-1H-pyrazole (2 mmol) in glacial acetic acid (15 ml) was stirred for 12 h at room temperature. Then the mixture was evaporated by rotary evaporation to remove the acetic acid, and recrystallized from a mixture of EtOH and DMF. Yield: 77%. (m.p. 475 K).