3-Methyl-1-(prop-2-en-1-yl)quinoxalin-2(1H)-one

In the molecule of the title compound, C12H12N2O, the quinoxaline ring is planar with an r.m.s. deviation of 0.007 (15) Å. The dihedral angle between the quinoxaline and propenyl planes is 82.1 (2)°. The crystal packing is stabilized by offset π–π stacking between the quinoxaline rings [centroid–centroid distance = 3.8832 (9) Å].

In the molecule of the title compound, C 12 H 12 N 2 O, the quinoxaline ring is planar with an r.m.s. deviation of 0.007 (15) Å . The dihedral angle between the quinoxaline and propenyl planes is 82.1 (2) . The crystal packing is stabilized by offsetstacking between the quinoxaline rings [centroid-centroid distance = 3.8832 (9) Å ].

Structure Reports Online
The dihedral angle between the quinoxaline and propenyl planes is 82.1 (2) (Fig. 1). Bond lengths and angles in title molecule are normal (Allen et al., 1987). The crystal packing is stabilized by offset π-π stacking between the quinoxalin rings.

Experimental
To a solution of 3-methylquinoxali-2(1H)-one (1 g) in 20 ml of dimethylformamide was added allylchloride (0.85 ml),K2CO3 (0.95 g) and catalytic amont of tetrabutylammonium bromide.The mixture was stirred at room temperature for 24 h.Then the solvent was remdove under reduce pressure,the residue was cristallized in ethanol to afford the product.

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 30 s 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 estimatedusing 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.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL datawill be even larger.