Diethyl Ether → 6,7-Dimethoxy-2-methylquinoxaline

Participants

Reaction Conditions

Reaction Steps

The title compound is prepared using an adaptation of the published method of Tamao, et al. Tetrahedron, 1982, 38, 3347-3354. To a THF solution under argon is added 2-Chloro-6,7-dimethoxyquinoxaline (5 g, 26 mmol) and NiCl2 (dppp) (0.14 g, 0.26 mmol). The reaction mixture is cooled to 0° C., and a 3 M solution of MeMgBr in Et2O (13 mL, 39 mmol) is added portionwise. The reaction mixture is allowed to warm to room temperature, stirred for 1 hours then refluxed for 1.5 hours. The mixture is cooled, quenched with 10% HCl, stirred 10 minutes, then made basic with 5% NaOH. CH2Cl2 and H2O are added to the reaction, and the mixture stirred overnight. Additional CH2Cl, H2O, and NaCl are then added and the mixture is filtered. The resulting solution is poured into a separatory funnel, and the aqueous layers are washed 3× with CH2Cl2. The organic layers are combined, washed with brine, dried (MgSO4), concentrated onto silica gel, and chromatographed (50%-80% EtOAc/hexanes) to provide a orange solid (49% yield).

Provenance & Evidence