反应详情

A solution of 8-bromo-N-(tert-butyl)-3-methylquinoxalin-2-amine (174a) (137 mg, 0.47 mmol), selenium dioxide (Aldrich; 57.0 mg, 0.51 mmol), and water (0.084 mL, 4.67 mmol) in 1,4-dioxane (5.0 mL) was stirred under argon at 60° C. for 19 h. The reaction mixture was then cooled to RT, diluted with DCM (5 mL), and adsorbed onto silica gel. Chromatographic purification (silica gel, 0-10% EtOAc/hexanes) furnished 5-bromo-3-(tert-butylamino)quinoxaline-2-carbaldehyde (132. mg, 0.43 mmol, 92% yield) as a yellow-orange solid. 1H NMR (400 MHz, CDCl3) δ ppm 10.14 (1H, s), 8.03 (1H, br. s.), 7.99 (1H, d, J=7.4 Hz), 7.88 (1H, d, J=8.4 Hz), 7.22-7.25 (1H, m), 1.64 (9H, s). m/z (ESI, +ve) 308.0/310.1 (M+H)+.

1. customChromatographic purification (silica gel, 0-10% EtOAc/hexanes)