Methanesulfonic Acid → 6-Bromo-2-(tetrahydro-2H-pyran-2-yl)-2H-indazol-5-ol

Participants

Reaction Steps

To a solution of 6-bromo-5-hydroxy-1H-indazole (725.0 g, 3.4 mol) in THF (10.2 L) is added DHP (336.5 mL, 3.57 mol) and CH3SO3H (65.4 g, 0.68 mol) at RT. The resulting mixture is stirred at RT for 22 hours. The reaction mixture is quenched with distilled water (6 L) and extracted with EtOAc (6 L). Saturated aqueous NaHCO3 solution (1100 mL) is added to adjust the pH to 8. After phase separation, the organic phase is washed with water (4 L) and then saturated aqueous sodium chloride (3 L), dried over anhydrous Na2SO4, filtered, and concentrated to give the product as a solid (1.64 kg, 99.3% yield). MS (m/z): 299.0 (M+H).

Provenance & Evidence