Hydrochloric Acid → 5-Bromo-3-(tert-butylamino)quinoxaline-2-carboxylic acid

Participants

Reaction Steps

To a slurry of 5-bromo-3-(tert-butylamino)quinoxaline-2-carbaldehyde (306a) (250 mg, 0.81 mmol) in MeOH (0.4 mL) and NaOH 1.0 N (1.62 mL, 1.62 mmol) was added two drops H2O2 30% in water (0.10 mL, 1.01 mmol) from a pasteur pipette. The reaction was stirred rapidly at RT and became a yellow/orange solution. Additional 0.05 mL 30% aq H2O2 was added. After 30 min, additional 0.05 mL 30% aq H2O2 was added. After 30 min, the reaction mixture was treated with ice, acidified to pH <2 with 1.0 N HCl, and diluted with 10 mL water. The orange suspension was filtered, rinsing with 10 mL of water to give 5-bromo-3-(tert-butylamino)quinoxaline-2-carboxylic acid (0.26 g, 0.80 mmol, 99% yield) as an orange solid. m/z (ESI, +ve ion) 324.0/326.0 (M+H)+.

Provenance & Evidence