24424-99-5

2458-12-0

231958-04-6

To a mixed solution of 3-amino-4-methylbenzoic acid (2.0 g, 13.2 mmol) in water (25 mL) and 1 N sodium hydroxide (25 mL) was added di-tert-butyl dicarbonate (4.3 g, 19.8 mmol). The reaction mixture was stirred at room temperature for 18 hours. After completion of the reaction, the mixture was extracted by partitioning with ethyl acetate and 5% aqueous citric acid. The organic layer was separated, washed sequentially with water and saturated saline, and then dried with anhydrous magnesium sulfate. The desiccant was removed by filtration and the filtrate was concentrated under reduced pressure to give 3-((tert-butoxycarbonyl)amino)-4-methylbenzoic acid as a pink solid (3.3 g, quantitative yield).