Methyl 2-[(methylsulfonyl)(propyl)amino]benzoate

The asymmetric unit of the title compound, C12H17NO4S, contains two molecules, both of which show disorder of the two terminal C atoms of the propyl chain over two sets of sites with an occupancy ratio of 0.581 (6):0.419 (6). Intramolecular C—H⋯O interactions help to establish the molecular conformations: in one molecule, the dihedral angle between the methyl ester group and the benzene ring is 41.0 (2)°, whereas in the other molecule it is 36.12 (17)°. In the crystal, molecules are linked by intermolecular C—H⋯O and C—H⋯π interactions.

The asymmetric unit of the title compound, C 12 H 17 NO 4 S, contains two molecules, both of which show disorder of the two terminal C atoms of the propyl chain over two sets of sites with an occupancy ratio of 0.581 (6):0.419 (6). Intramolecular C-HÁ Á ÁO interactions help to establish the molecular conformations: in one molecule, the dihedral angle between the methyl ester group and the benzene ring is 41.0 (2) , whereas in the other molecule it is 36.12 (17) . In the crystal, molecules are linked by intermolecular C-HÁ Á ÁO and C-HÁ Á Á interactions.

Comment
In continuation to our work on the synthesis of benzothiazine derivatives, we have reported various molecules of this series (Shafiq et al., 2008(Shafiq et al., , 2009a(Shafiq et al., , 2009b. The title compound (I, Fig. 1, Fig. 2) is being reported here in this context.
The asymmtric unit of title compound consists of two molecules. In both molecules the two terminal C-atoms of propyl moiety are disordered over two set of sites with occupancy ratio of 0.581 (6):0.419 (6). The two molecules of asymmetric units differ from each other as the dihedral angle between methyl ester A (O2/C1/O1/C8) with benzene ring B (C2-C7) is 40.96 (21)°, whereas in the other molecule it is 36.12 (17)° between C (O6/C13/O5/C20) and D (C13-C19). The molecules are stabilized due to intra as well as intermolecular and C-H···π interactions (Table 1, Fig. 2).

Experimental
For the preparation of the title compound, the suspension of hexane-washed sodium hydride (50% in mineral oil) was prepared in dry dimethylformamide (3 ml). A solution of methyl N-methylsulfonylanthranilate (70 mg, 0.306 mmol) in dry dimethylformamide (5 ml) was added to the suspension and stirred for 45 min at room temperature. Then, a solution of propyl iodide (156.40 mg, 0.92 mmol) was added to it. The resulting white suspension was stirred for 2.5-3 h, added to ice and pH adjusted at 4-4.5 and kept in freezer. Solid product obtained was filtered and dried to obtain white prisms of title compound.

Refinement
The two terminal C-atoms of each molecule are disordered over two set of sites. The disordered C-atoms were treated anisotropic with EADP and refined using DFIX.