Hydrogen Peroxide → 2-Amino-6-bromobenzoic acid

Participants

Reaction Conditions

Reaction Steps

To 4-bromoindoline-2,3-dione (8.94 g, 39.6 mmol) was added 1.0 M sodium hydroxide (40 mL, 120 mmol) to give a dark brown mixture. The mixture was heated to 80° C. then 20% hydrogen peroxide (9 mL, 88 mmol) was added slowly over 15 min (caution: a strong exotherm was observed upon reagent addition). The mixture was then stirred at 80° C. for 1 h. After this time, the mixture was cooled in an ice bath to ˜10° C. and then concentrated to a residue. HCl was added cautiously to the residue until the pH of the mixture was 4-5. Once at the prescribed pH, the mixture was then concentrated to dryness and MeOH (150 ml) was added. The resulting suspension stirred for 15 min and then filtered. The filtrate was concentrated to dryness and dried under vacuum for 14 h to yield 2-amino-6-bromobenzoic acid (9.18 g) as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 6.72 (1H, t, J=7.91 Hz), 6.60 (1H, dd, J=7.78, 1.00 Hz), 6.52 (1H, dd, J=7.91, 1.13 Hz). LCMS Method D: retention time 0.68 min, [M+1] 200.0.

Provenance & Evidence