3,4-Dimethyl-2-(2-oxo-2-phenyl­eth­yl)-2H,4H-pyrazolo­[4,3-c][1,2]benzothia­zine-5,5-dione

Sana Aslam; Hamid Latif Siddiqui; Matloob Ahmad; Iftikhar Hussain Bukhari; Masood Parvez

doi:10.1107/S1600536812002188

. 2012 Jan 21;68(Pt 2):o502. doi: 10.1107/S1600536812002188

3,4-Dimethyl-2-(2-oxo-2-phenylethyl)-2H,4H-pyrazolo[4,3-c][1,2]benzothiazine-5,5-dione

Sana Aslam ^a, Hamid Latif Siddiqui ^a,^*, Matloob Ahmad ^b, Iftikhar Hussain Bukhari ^b, Masood Parvez ^c

PMCID: PMC3275247 PMID: 22347103

Abstract

In the title molecule, C₁₉H₁₇N₃O₃S, the heterocyclic thiazine ring adopts a half-chair conformation with the S and N atoms displaced by 0.530 (5) and 0.229 (6) Å, respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The ethanone group lies at an angle of 3.8 (3)° with respect to the benzene ring, which lies almost perendicular to the pyrazole ring, with a dihedral between the two planes of 89.22 (11)°. Weak intermolecular C—H⋯O hydrogen-bonding interactions are present.

Related literature

For the biological activity of pyrazoles, see: Farag et al. (2008 ▶); Ciciani et al. (2008 ▶); Cunico et al. (2006 ▶); Ahmad et al. (2010 ▶). For related structures, see: Siddiqui et al. (2008 ▶).

Experimental

Crystal data

C₁₉H₁₇N₃O₃S
M _r = 367.42
Monoclinic,
a = 24.380 (6) Å
b = 11.141 (4) Å
c = 14.996 (5) Å
β = 120.76 (2)°
V = 3500.1 (19) Å³
Z = 8
Mo Kα radiation
μ = 0.21 mm⁻¹
T = 200 K
0.12 × 0.10 × 0.08 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SORTAV; Blessing, 1997 ▶) T _min = 0.975, T _max = 0.983
12615 measured reflections
3970 independent reflections
2847 reflections with I > 2σ(I)
R _int = 0.073

Refinement

R[F ² > 2σ(F ²)] = 0.069
wR(F ²) = 0.146
S = 1.15
3970 reflections
237 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Data collection: COLLECT (Hooft, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶); data reduction: SCALEPACK (Otwinowski & Minor, 1997 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812002188/pk2383sup1.cif

e-68-0o502-sup1.cif^{(20.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812002188/pk2383Isup2.hkl

e-68-0o502-Isup2.hkl^{(190.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812002188/pk2383Isup3.cml

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
C1—H1⋯O2ⁱ	0.95	2.43	3.246 (5)	144
C9—H9B⋯O1ⁱⁱ	0.98	2.46	3.413 (4)	163
C11—H11C⋯O1ⁱⁱⁱ	0.98	2.44	3.406 (4)	168

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

Acknowledgments

The authors are grateful to the Higher Education Commission, Pakistan, and the Institute of Chemistry, University of the Punjab, Lahore, Pakistan, for financial support.

supplementary crystallographic information

Comment

Both benzothiazines and pyrazoles are known as versatile biologically active heterocyclic nuclei. Pyrazoles are found to be cytotoxic agents (Ciciani et al., 2008), anti-tumor (Farag et al., 2008), anti-malarial (Cunico et al., 2006), etc. In continuation of our research interests in biologically active molecules (Ahmad et al., 2010), we have fused both of these heterocycles and herein report the synthesis and crystal structure of the title compound.

The bond distances and angles in the title molecule (Fig. 1) agree very well with the corresponding bond distances and angles reported in closely related compounds (Siddiqui et al., 2008). The heterocyclic thiazine ring adopts a half chair conformation with atoms S1 and N1 displaced by 0.530 (5) and 0.229 (6) Å, respectively, on opposite sides from the mean plane formed by the remaining ring atoms. The ethanone group O3/C12/C13/C14 is oriented at 3.8 (3) °, with the benzene ring (C14–C19) which lies almost perpendicular to the pyrazolyl ring (N2/N3/C7/C8/C10) with a dihedral between the two planes of 89.22 (11)°. The structure is devoid of classical hydrogen bonds. However, intermolecular hydrogen bonding interactions of C—H···O type are present (Table 1).

Experimental

Equimolar quantities of 3,4-dimethyl-2,4-dihydropyrazolo[4,3-c][1,2] benzothiazine 5,5-dioxide (1.0 g, 4.01 mmol) and corresponding phenacyl bromide (0.80 g, 4.01 mmol) were dissolved in acetonitrile (20 ml) followed by the addition of equimolar K₂CO₃ (0.55 g, 4.01 mmol). The mixture was subjected to reflux for 7 h. The completion of reaction was monitored with the help of TLC. The precipitates of the title compound were collected and washed with methanol. The crystals suitable for X-ray crystallographic analysis were grown from a solution of CHCl₃:MeOH in 1:1 ratio.