b) Methyl 6-bromo-1-isopropyl-1H-indazole-4-carboxylate (0.58 g, 1.952 mmol) was dissolved in a solvent mixture of methanol (12 mL) and tetrahydrofuran (3 mL). A 3N NaOH solution (3.25 mL, 9.76 mmol) was added slowly via syringe and the reaction mixture was stirred at room temperature for 3 hours. Upon completion of the reaction, the volatile solvent was removed under vacuum and the residue was diluted with water and the pH was adjusted to 4-5 by slow dropwise addition of 1 N HCl. The aqueous phase was extracted with a 20% THF/EtOAc solvent mixture (3 times). The organic phases were combined, washed with saturated brine, dried over anhydrous MgSO4, filtered and concentrated to afford 6-bromo-1-isopropyl-1H-indazole-4-carboxylic acid (0.52 g, 94% yield). The product was characterized by 1H NMR (400 MHz, DMSO-d6) and LC-MS (ES): 1H NMR δ 13.54 (s, 1H), 8.36-8.43 (m, 2H), 7.82 (d, J = 1.52 Hz, 1H), 5.11 (quin, J = 6.57 Hz, 1H), 1.48 (s, 3H), 1.47 ( s, 3H); LC-MS (ES) [M + H]+ 283.4/285.2.
