General procedure for the synthesis of methyl 5-amino-2,4-difluorobenzoate from methyl 2,4-difluoro-5-nitrobenzoate: to a solution of methyl 2,4-difluoro-5-nitrobenzoate (12.0 g, 0.06 mol, 1 eq.) in acetic acid (150 mL) and water was added iron powder (12.3 g, 0.22 mol, 4 eq.). The reaction mixture was heated to 40 °C and kept for 1.5 hours. After completion of the reaction, the mixture was filtered through a diatomaceous earth pad and the filtrate was extracted with ethyl acetate. The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated to afford methyl 5-amino-2,4-difluorobenzoate (10.0 g, 96% yield) as a brown solid.1H NMR (400 MHz, DMSO-d6) δppm: 7.27 (dd, J=9.98,7.42 Hz, 1H), 7.14 (t, J=10.99 Hz, 1H), 5.28 (s, 2H), 3.77 (s, 3H).ES-LCMS: m/z 189.0 (M+H).
