Acetic Acid → 2-Amino-4,6-dimethoxybenzoic acid

Participants

Reaction Conditions

Reaction Steps

To a mixture of 4,6-dimethoxyindoline-2,3-dione (20.28 g, 97.9 mmol) in 30% NaOH solution (100 mL) at 100° C. was carefully dropped a 50% H2O2 solution. It was heated at 100° C. for 20 minutes. It was cooled down and neutralized by concentrated HCl to pH 8, followed by acetic acid to pH 5 to form a solid. It was filtered, washed with water, and dried under vacuum with P2O5 to afford 2-amino-4,6-dimethoxybenzoic acid as a yellow solid (15.034 g, 78%). 1H NMR (300 MHz, DMSO-d6) δ 6.00 (d, 1H), 5.85 (d, 1H), 3.83 (s, 3H), 3.77 (s, 3H), 3.41 (br, 2H); LC-MS (ESI) m/z 198 (M+H)+.

Provenance & Evidence