Hydrochloric Acid → 5-Bromo-4-methylisoxazole-3-carboxylic acid

To a solution of ethyl 5-bromo-4-methylisoxazole-3-carboxylate (Intermediate A) (8.65 g, 37.0 mmol) in MeOH (100 mL) was added 2M NaOH (aq) (18.48 mL, 37.0 mmol). The reaction mixture was stirred at room temperature for 10 minutes and the resulting mixture was acidified using 1M HCl (aq) and concentrated under reduced pressure to remove MeOH. The aqueous was diluted with water and extracted with EtOAc (×3) and the combined organic extracts were dried over MgSO4 and filtered. The solvent was removed under reduced pressure to afford the title compound;