Boron tribromide → 6-Bromo-1H-indazol-5-ol

Participants

Reaction Steps

To a solution of 6-bromo-5-methoxy-1H-indazole (60 g, 0.265 mol) in DCM (1300 mL) is added a solution of BBr3 (105 g, 0.42 mol) in DCM (200 mL) at 0° C. The reaction mixture is warmed to RT and stirred overnight. Then the reaction solution is quenched with MeOH at 0° C. The solvent is removed in vacuo and the residue is neutralized with NaHCO3 solid. The mixture is partitioned by water (1500 mL) and EtOAc (1500 mL). The aqueous layer is extracted with EtOAc (1500 mL) two times. The combined organic layers are dried and concentrated to give crude product, which is purified by silica gel column chromatography (PE:THF=2:1) to give the desired product (42.5 g, 75% yield). MS (m/z): 215.0 (M+H).

Provenance & Evidence