A solution of 2-fluoro-5-methoxy- 4-nitrobenzoic acid (10 g, 46 mmol), HOAc (50 mL), and MeOH (50 mL) was hydrogenated using a hydrogen balloon overnight. The solution was then filtered through celite and concentrated to a residue, which was triturated with ether and ethyl acetate. The solid was filtered and dried to give the product 4-Amino-2-fluoro-5-methoxybenzoic acid as a light yellow powder (8.3 g, 98 %).
[1] Patent: WO2009/42711, 2009, A1. Location in patent: Page/Page column 266
[2] Patent: US2008/9482, 2008, A1. Location in patent: Page/Page column 134
[3] Patent: WO2008/40951, 2008, A1. Location in patent: Page/Page column 150
[4] Patent: WO2009/42711, 2009, A1. Location in patent: Page/Page column 387-388
