Methanol → Methyl 5-amino-2-bromo-4-methylbenzoate

To a cooled solution (5° C.) of 5-amino-2-bromo-4-methylbenzoic acid (100.0 g, 0.434 mmol) in anhydrous methanol (1.6 L) was added dropwise thionyl chloride (112.4 g). The reaction mixture was refluxed and monitored by TLC. After refluxing for 6 h, the reaction was complete. The reaction solution was concentrated under reduced pressure. The residue was diluted with ice water (1.2 L) and neutralized with 5% NaHCO3 to pH 7.5. The aqueous layer was extracted with EtOAc (3×600 mL), and the combined organic layers were washed with brine (2×500 mL), and dried over anhydrous Na2SO4. Concentration under reduced pressure provided the title compound as a pale solid. Yield: 99%. 1H-NMR (DMSO-d6, 300 MHz): δ 7.25 (s, 1H), 7.14 (s, 1H), 3.30 (s, 3H), 2.15 (s, 3H); MS ESI (m/z) 244 [M+1]+, calc. 243.