6942-36-5

6942-37-6

General procedure for the synthesis of methyl 5-amino-2-bromobenzoate from methyl 2-bromo-5-nitrobenzoate: Methyl 2-bromo-5-nitrobenzoate (25.3 g, 97.3 mmol) was dissolved in anhydrous methanol (500 mL), followed by addition of stannous (II) chloride (93.3 g, 487 mmol). The reaction mixture was heated to reflux for 2 hours. Upon completion of the reaction, the mixture was cooled, ethyl acetate (500 mL) and water (100 mL) were added, and the reaction mixture was neutralized with 4N aqueous sodium hydroxide solution, followed by filtration through diatomaceous earth. The filtrate was concentrated under reduced pressure, ethyl acetate (200 mL) was added, and washed sequentially with saturated aqueous sodium bicarbonate (200 mL, 2 times), water (200 mL), and saturated brine (200 mL). The organic layer was dried with anhydrous magnesium sulfate and the solvent was removed under reduced pressure to afford the title compound methyl 5-amino-2-bromobenzoate (21.0 g) as a pale yellow oil in 94% yield.1H-NMR (400 MHz, DMSO-d6) δ 3.80 (s, 3H), 5.55 (s, 2H), 6.63 (dd, J = 8.8, 2.8 Hz, 1H), 6.94 (d, J = 2.8 Hz, 1H), 7.29 (d, J = 8.8 Hz, 1H).