2-Methyl-3-(n-octylsulfanyl)quinoxaline

All the non-H atoms of the title compound, C17H24N2S, lie almost in a common plane (r.m.s. deviation = 0.049 Å). The octyl chain adopts an all-trans conformation.

Bond lengths and angles in title molecule ( Fig.1) are normal.

Experimental
To a solution of 3-methylequinoxaline-2(1H)-thione (1 g, 5.68053 mmol) in dimethylformamide (20 ml), was added CH 3 (CH 2 ) 6 C 2 I ,K 2 CO 3 (1 g, 7.46 mmol) and a catalytic quantity of tetrabutylammoniumbromide. The mixture was stirred at room temperature for 24 h. The solution was filtered to remove the salts. The solvent was removed under reduced pressure.
The residue was crystallized in ethanol to afford the title compound as colourless crystals.

Refinement
All H atoms were geometrically positioned and treated as riding with C methyl -H = 0.96 Å, C methylene -H = 0.97 Å and C aromatic -H = 0.93 Å with U(H) = 1.2U eq (C) or U(H) = 1.5U eq (C methyl ) . Fig. 1. : Molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.

Special details
Experimental. The data collection nominally covered a sphere of reciprocal space, by a combination of seven sets of exposures; each set had a different φ angle for the crystal and each exposure covered 0.5° in ω and 25 seconds in time. The crystal-to-detector distance was 37.5 mm.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.