Methyl 4-acet­oxy-2-methyl-2H-1,2-benzothia­zine-3-carboxyl­ate 1,1-dioxide

Matloob Ahmad; Hamid Latif Siddiqui; Saeed Ahmad; Muhammad Irfan Ashiq; Graham John Tizzard

doi:10.1107/S1600536808004029

. 2008 Feb 15;64(Pt 3):o594. doi: 10.1107/S1600536808004029

Methyl 4-acetoxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide

Matloob Ahmad ^a, Hamid Latif Siddiqui ^a,^*, Saeed Ahmad ^b, Muhammad Irfan Ashiq ^a, Graham John Tizzard ^c

PMCID: PMC2960850 PMID: 21201932

Abstract

In the title compound, C₁₃H₁₃NO₆S, the thiazine ring adopts a distorted half-chair conformation. Each molecule is linked to its neighbour through intermolecular C—H⋯O hydrogen bonds.

Related literature

For related literature, see: Fabiola et al. (1998 ▶); Golič & Leban (1987 ▶); Kojić-Prodić & Rużić-Toroš (1982 ▶); Rajagopal & Seshadri (1990 ▶); Reck et al. (1988 ▶); Rehman et al. (2005 ▶, 2006 ▶); Turck et al. (1996 ▶).

Experimental

Crystal data

C₁₃H₁₃NO₆S
M _r = 311.30
Monoclinic,
a = 6.8917 (5) Å
b = 24.1814 (17) Å
c = 8.2861 (5) Å
β = 97.876 (4)°
V = 1367.86 (16) Å³
Z = 4
Mo Kα radiation
μ = 0.26 mm⁻¹
T = 120 (2) K
0.40 × 0.20 × 0.20 mm

Data collection

Bruker Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ▶) T _min = 0.902, T _max = 0.949
12265 measured reflections
3032 independent reflections
2183 reflections with I > 2σ(I)
R _int = 0.057

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.145
S = 1.03
3032 reflections
193 parameters
H-atom parameters constrained
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.55 e Å⁻³

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CAMERON (Pearce & Watkin, 1993 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808004029/kp2156sup1.cif

e-64-0o594-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808004029/kp2156Isup2.hkl

e-64-0o594-Isup2.hkl^{(145.8KB, 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
C13—H13A⋯O4ⁱ	0.98	2.48	3.387 (3)	153
C5—H5⋯O1ⁱ	0.95	2.48	3.349 (3)	151

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge financial support from the Higher Education Commission of Pakistan and the University of the Punjab, Lahore.

supplementary crystallographic information

Comment

Among the vast class of benzothiazines, 1,2-benzothiazine1,1-dioxides are the most versatile compounds due to their applications in various fields such as pharmaceuticals (Turck et al., 1996), dyes (Rajagopal & Seshadri, 1990) and fungicides. In continuation of our investigation of the chemistry of 1,2-benzothiazine 1,1-dioxide derivatives (Rehman et al., 2005; Rehman et al., 2006) we have synthesized the title compound (I) and its crystal structure is reported here.

In (I) (Fig. 1), the benzene ring of the benzothiazine nucleus is planar (the maximum least square deviation from the plane of the atoms involved is 0.01 Å) while the thiazine ring adopts a distorted half chair conformation. N1 has a pyramidal geometry projecting the methyl group approximately perpendicular to the thiazine ring. Atoms O1, O3 and O5 lie approximately in the plane of the ring while O2 lies almost perpendicular to it.

The C7—O3 bond length in (I) is longer [1.389 (3)] than in the related molecules having no substitution at O3 [1.352 (9) Å; Golič & Leban, 1987; 1.350 (9) Å; Reck et al., 1988].

C9—O4 bond length [1.201 (13) Å] is observed to be shorter than in its previously reported non acylated analogue [1.262 (10) Å; Golič & Leban, 1987] due to no involvement of O4 electrons in the hydrogen bonding. O4 lies almost perpendicular to the thiazine ring and the bond angle C7—C8—C9 [127.3 (2) Å] is greater than observed in the related hydrogen bonded oxicams [121.0 (3) Å; Kojić-Prodić & Rużić-Toroš, 1982; 120.9 (2) Å, Fabiola et al., 1998]. Molecules are linked by C—H···O hydrogen bonds (Table1) forming a chain along a axis.

Experimental

Acetyl chloride (1.57 g; 10 mmol) was slowly added to a mixture of methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate1,1-dioxide (1.345 g; 5 mmol), triethylamine (0.71 g; 7 mmol) and carbon tetrachloride (25 ml) under nitrogen atmosphere at 273 K. The mixture was stirred for a period of three hours at room temperature and the solvent was evaporated under vacuum. A residue was poured over ice-water mixture to get the white coloured product which was washed with cold water and recrystallized from chloroform-methanol mixture (1:1). Yield 1.31 g; 84°; m.p. 422 K.