Methyl 5-amino-2,4-difluorobenzoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of methyl 5-amino-2,4-difluorobenzoate (252 mg, 1.35 mmol) and pyridine (0.13 mL, 1.61 mmol) in 5 mL CH2Cl2 was added methanesulfonyl chloride (0.12 mL, 1.48 mmol). After 24 h at room temperature, the reaction mixture was washed with saturated aqueous NaHCO3 and extracted with CHCl3 to provide crude methyl 2,4-difluoro-5-[(methylsulfonyl)amino]benzoate as a solid (ESI-MS 264 (M−H)), which was hydrolyzed using aqueous NaOH to provide 2,4-difluoro-5-[(methylsulfonyl)amino]benzoic acid (ESI-MS 250 (M−H)), which was used without further purification. the reaction mixture was washed with saturated aqueous NaHCO3 extracted with CHCl3