Methyl 4-[(tert-butoxycarbonyl)amino]-2,6-difluorobenzoate (36 mg, 0.125 mmol) was used as a starting material and 0.5 mL of trifluoroacetic acid (TFA) was added to its solution in 1 mL of dichloromethane at room temperature. The reaction mixture was stirred for 30 minutes at room temperature. Subsequently, the reaction solution was concentrated under reduced pressure and the residue was co-evaporated with dichloromethane and toluene several times to completely remove the residual trifluoroacetic acid. Finally, the product was dried under reduced pressure. The resulting crude product, methyl 4-amino-2,6-difluorobenzoate (24 mg, quantitative yield), could be used in subsequent reactions without further purification.
