24424-99-5

99-05-8

111331-82-9

GENERAL METHOD: To a stirred solution of m-aminobenzoic acid (5.00 g, 36.5 mmol) and sodium hydroxide (1.56 g, 39.3 mmol) in a solvent mixture of 1:1 water/dioxane (60 mL) at 0 °C was slowly added di-tert-butyl dicarbonate (14.3 g, 65.4 mmol). The reaction mixture was continued to be stirred at 0 °C for 3 h, followed by slow warming to room temperature and stirring overnight. After completion of the reaction, the reaction mixture was extracted with ethyl acetate (60 mL) and the extraction was repeated once (60 mL). The organic phases were combined and neutralized with 1 M aqueous KHSO4 to pH ≈ 7. The organic layer was separated, washed with water (60 mL) and dried over anhydrous magnesium sulfate. The solvent was removed by concentration under reduced pressure to give 3-(N-Boc-amino)benzoic acid (7.53 g, 87% yield) as an off-white solid, which could be used in the next reaction without further purification.