6-Bromo-1-methyl-1H-2,1-benzothia­zin-4(3H)-one 2,2-dioxide

Muhammad Shafiq; M Nawaz Tahir; Islam Ullah Khan; Muhammad Nadeem Arshad; Muhammad Nadeem Asghar

doi:10.1107/S1600536809015980

. 2009 Apr 30;65(Pt 5):o1182. doi: 10.1107/S1600536809015980

6-Bromo-1-methyl-1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide

Muhammad Shafiq ^a, M Nawaz Tahir ^b,^*, Islam Ullah Khan ^a, Muhammad Nadeem Arshad ^a, Muhammad Nadeem Asghar ^a

PMCID: PMC2977846 PMID: 21583983

Abstract

In the crystal structure of the title compound, C₉H₈BrNO₃S, the thiazine ring is in the twisted form. In the crystal, pairs of intermolecular C—H⋯O hydrogen bonds form inversion dimers with an R ₂ ²(8) ring motif. Weak intermolecular C—H⋯Br and C—H⋯π interactions are also present.

Related literature

For the structures of benzothiazine derivatives, see: Arshad et al. (2008 ▶); Shafiq et al. (2008a ▶,b ▶); Tahir et al. (2008 ▶). For the related structure, 6-bromo-1-methyl-1H-benzo[c][1,2]thiazin-4(3H)-one 2,2-dioxide, see: Shafiq et al. (2009 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For the synthesis, see: Lombardino (1972 ▶).

Experimental

Crystal data

C₉H₈BrNO₃S
M _r = 290.13
Monoclinic,
a = 5.4577 (3) Å
b = 12.6400 (8) Å
c = 15.1258 (10) Å
β = 96.204 (2)°
V = 1037.35 (11) Å³
Z = 4
Mo Kα radiation
μ = 4.15 mm⁻¹
T = 296 K
0.20 × 0.17 × 0.15 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.439, T _max = 0.540
11077 measured reflections
2234 independent reflections
1709 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.030
wR(F ²) = 0.072
S = 1.04
2234 reflections
137 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; 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 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809015980/fb2142sup1.cif

e-65-o1182-sup1.cif^{(16.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809015980/fb2142Isup2.hkl

e-65-o1182-Isup2.hkl^{(107.6KB, 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
C3—H3⋯O3ⁱ	0.93	2.54	3.308 (4)	140
C8—H8A⋯O2ⁱⁱ	0.97	2.54	3.470 (3)	162
C9—H9B⋯O3	0.96	2.41	2.824 (3)	106
C5—H5⋯Br1ⁱⁱⁱ	0.93	2.94	3.871 (3)	175
C9—H9A⋯Br1^iv	0.96	3.01	3.871 (2)	150
C9—H9C⋯Cg1^v	0.96	2.83	3.449 (3)	123

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) . Cg1 is the centroid of the C1–C6 ring.

Acknowledgments

MS gratefully acknowledges the Higher Education Commission, Islamabad, Pakistan, for providing a Scholarship under the Indigenous PhD Program (PIN 042–120567-PS2–276).

supplementary crystallographic information

Comment

We have reported crystal structures of the synthesized derivatives of the benzothiazine molecule (Shafiq et al., 2008a; Shafiq et al., 2008b; Tahir et al., 2008; Arshad et al., 2008). Here we report the title compound (I), (Fig. 1), that belongs to this series of the structures.

(I) is closely related to the crystal structure of 6-bromo-1-methyl-1H-benzo[c][1,2]thiazin-4(3H)-one 2,2-dioxide, (II), (Shafiq et al., 2009). (I) and (II) differ by the presence of the methyl and ethyl groups at the N-atom, respectively. The bromo-substituted benzene ring A (C1—C6) is planar with Br deviated by 0.064 (4) Å from the mean plane. The thiazine ring B (S1/N1/C1/C6—C8) is in the twisted form, with the maximum puckering amplitude Q_T = 0.577 (2) Å (Cremer & Pople, 1975). The title molecules form dimers interconnected by a pair of the intermolecular H-bonds C8–H8A···O2ⁱ [symmetry code: i = -x + 1, -y, -z + 1] with the R₂²(8) ring motif (Bernstein et al., 1995), (Tab. 1, Fig. 2). The dimers are linked to each other forming helices through the other intermolecular H-bonding C3–H3···O3ⁱⁱ [symmetry code: ii = -x + 3/2, y + 1/2, -z + 1/2]. The molecules are also stabilized due to C—H···π-electron interaction with the benzene group and intermolecular C—H···Br interactions (Tab. 1).

Experimental

The title compound was prepared in a three step scheme following the reported procedure (Lombardino, 1972). In the first step, methyl-2-amino-5-bromobenzoate (92 mg, 4 mmol) was put in dichloromethane (10 ml) and this mixture was introduced into a round bottom flask. A solution of methanesulfonyl chloride (550 mg, 4.8 mmol) in dichloromethane (10 ml) was slowly added (10-15 minutes) to this mixture. The mixture was stirred at 60–70 °C for 2–3 days keeping pH of the mixture alkaline by triethylamine. After the completion of the reaction, the solvent was evaporated under reduced pressure to get methyl-5-bromo-2-[(methylsulfonyl)amino] benzoate.

In the second step, methyl-5-bromo-2-[(methylsulfonyl)amino] benzoate (1.02 g, 3.3 mmol) was introduced into 5 ml of N,N-dimethylformamide (DMF). The mixture was added to a suspension of NaH (158.38 mg, 6.6 mmol) in DMF (10 ml). The mixture was stirred at room temperature for 14–16 h. After that, methyl-5-bromo-2-[methyl(methylsulfonyl)amino]benzoate was obtained.

In the third step methyl-5-bromo-2-[methyl(methylsulfonyl)amino]benzoate was cyclized. Therefore methyl-5-bromo-2-[methyl(methylsulfonyl)amino]benzoate (418.83 mg, 1.3 mmol) was introduced in DMF (5 ml) and added to the suspension of NaH (59.99 mg, 2.5 mmol) in DMF (10 ml). The mixture was stirred at room temperature for 3–4 h. Then the reaction mixture was poured into ice and clear solution was obtained. The pH of this solution was adjusted between 5–6. The precipitated crude product was recrystallized from ethanol. Yellow needle-shaped crystals of the title compound of suitable size for structure analysis were grown in this way.