2-(3,4-Dimethyl-5,5-dioxo-2H,4H-pyrazolo[4,3-c][1,2]benzothia­zin-2-yl)-N′-(2-thienylmethyl­idene)acetohydrazide

Matloob Ahmad; Hamid Latif Siddiqui; Altaf Hussain Khan; Masood Parvez

doi:10.1107/S1600536810015084

. 2010 May 8;66(Pt 6):o1265–o1266. doi: 10.1107/S1600536810015084

2-(3,4-Dimethyl-5,5-dioxo-2H,4H-pyrazolo[4,3-c][1,2]benzothiazin-2-yl)-N′-(2-thienylmethylidene)acetohydrazide

Matloob Ahmad ^a, Hamid Latif Siddiqui ^b,^*, Altaf Hussain Khan ^b, Masood Parvez ^c

PMCID: PMC2979531 PMID: 21579367

Abstract

In the title molecule, C₁₈H₁₇N₅O₃S₂, the heterocyclic thiazine ring adopts a twist boat conformation, with the S and N atoms displaced by 0.480 (7) and 0.205 (8) Å, respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The pyrazole and benzene rings are tilted at an angle of 10.9 (2)° with respect to one another. The crystal structure is stabilized by intermolecular N—H⋯O and C—H⋯N hydrogen bonds, resulting in dimers forming nine-membered rings of graph-set motif R ₂ ²(9). In addition, intermolecular C—H⋯O interactions result in chains of molecules along the c axis, further consolidating the crystal packing.

Related literature

For the use of 1,2-benzothiazine derivatives as anti-inflammatory drugs, see: Lombardino et al. (1973 ▶); Zia-ur-Rehman et al. (2006 ▶). For the synthesis of benzothiazine derivatives, see: Ahmad et al. (2010 ▶). For related structures, see: Ahmad et al. (2010 ▶). For graph-set notation, see: Bernstein et al. (1994 ▶).

Experimental

Crystal data

C₁₈H₁₇N₅O₃S₂
M _r = 415.49
Orthorhombic,
a = 18.5474 (2) Å
b = 11.6670 (5) Å
c = 8.4783 (7) Å
V = 1834.64 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.32 mm⁻¹
T = 173 K
0.28 × 0.06 × 0.04 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SORTAV; Blessing, 1997 ▶) T _min = 0.915, T _max = 0.987
3078 measured reflections
1725 independent reflections
1623 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.087
S = 1.09
1725 reflections
255 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.20 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 datablocks global, I. DOI: 10.1107/S1600536810015084/jh2146sup1.cif

e-66-o1265-sup1.cif^{(21.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015084/jh2146Isup2.hkl

e-66-o1265-Isup2.hkl^{(83.2KB, 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
N4—H4N⋯O3ⁱ	0.88	2.10	2.964 (4)	166
C12—H12A⋯N5ⁱ	0.99	2.52	3.488 (5)	164
C11—H11B⋯O1ⁱⁱ	0.98	2.40	3.243 (6)	143

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

Acknowledgments

HLS is grateful to the Higher Education Commission, Islamabad, and the University of the Punjab, Lahore, for financial support.

supplementary crystallographic information

Comment

Benzothiazines represent a class of heterocyclic compounds which exhibit a diverse range of biological activities like anti-inflammatory (Lombardino et al., 1973), antibacterial (Zia-ur-Rehman et al., 2006), etc. Continuing our research on the synthesis of potential biologically active derivatives of benzothiazines, we have fused a pyrazole ring with benzothiazine nucleus and the resulting compounds were found to be potent antioxidants (Ahmad et al., 2010). Herein we report the synthesis and crystal structure of the title compound.

In the title compound (Fig. 1), the bond distances and angles agree with the cortresponding bond distances and angles reported in a closely related compound (Ahmad et al., 2010). The heterocyclic thiazine ring adopts a twist boat conformation with atoms S1 and N1 displaced by 0.480 (7) and 0.205 (8) Å on the opposite sides from the mean planes formed by the remaining ring atoms. The pyrazol and phenyl rings are tilted at 10.9 (2)° with respect to each other. The atoms (S2/O3/N4/N5/C12—C18) of the thiophenylmethylideneacetohydrazide moiety are almost planar with meaximum deviation being 0.070 (3) Å for N4.

The structure is stabilized by intermolecular hydrogen bonds N4—H4N···O3 and C12—H12A···N5, resulting in dimers forming nine membered rings in R₂²(9) graph set motif (Bernstein et al., 1994). In addition, intermolecular interactions C12—H12B···O1 leading to chains of molecules along the c-axis further consolidate the crystal packing; the details of hydrogen bonding geometry have been provided in Tab. 1 and Fig. 2.

Experimental

A mixture of 2-(3,4-dimethyl-5,5-dioxidopyrazolo[4,3-c][1,2]benzothiazin -2(4H)-yl)acetohydrazide (10 mmoles), 2-formyl thiophene (12 mmoles), methanol (50 ml) and 2 drops of o-phosphoric acid were subjected to reflux for 3 hours. The precipitates formed were collected and washed with methanol. Crystals suitable for XRD were grown in dimethylformamide. mp. 556-557 K, MS m/z: 415.0(M+).