The general procedure for the synthesis of methyl 3-amino-2-hydroxybenzoate from methyl 2-hydroxy-3-nitrobenzoate was as follows: a suspension of methyl 2-hydroxy-3-nitrobenzoate (18.1 g, 93 mmol) with 5% palladium carbon (5 g) in methanol (200 mL) was placed in a Parr flask at room temperature and shaken for 49 hr under hydrogen (60 psi) atmosphere. Upon completion of the reaction, the reaction mixture was filtered through a diatomaceous earth plug and the filtrate was concentrated under reduced pressure to remove the solvent to afford methyl 3-amino-2-hydroxybenzoate (15.6 g, yield > 99%) as a yellow solid. The structure of the product was confirmed by 1H NMR (CDCl3): δ 10.87 (s, 1H), 7.23 (dd, J = 7.7 Hz, 2H), 6.87 (t, J = 9.9 Hz, 1H), 3.95 (s, 3H), 3.80 (br s, 2H); ESI MS m/z 168 [C8H9NO3 + H]+.
