Boron tribromide → 1-(4-Hydroxyphenyl)-1H-indazol-4-ol

Participants

Reaction Conditions

Reaction Steps

1-[4-(Methyloxy)phenyl]-4-[(phenylmethyl)oxy]-1H-indazole (D32) (40 mg, 0.121 mmol) was dissolved in dry DCM (1.5 mL) under argon and cooled to −78° C. in a dry ice-acetone bath. After 5 minutes BBr3 (1M in DCM, 0.242 mL, 0.242 mmol) was added dropwise and when the addition was complete the bath was removed and it was allowed to reach room temperature. The reaction was followed by LC-MS. After 4 hours more BBr3 (1M in DCM, 0.242 mL, 0.242 mmol) was added to the mixture and after 21 hours it was concentrated in vacuo. The residue was partitioned between EtOAc (25 mL)/water (25 mL), the pH adjusted to 7 by addition of a solution of NaHCO3 and the layers separated. The aqueous phase was extracted with EtOAc (2×25 mL) and the combined organics were dried over MgSO4, filtered and concentrated in vacuo. The crude material (28 mg) was purified by flash chromatography (Biotage SP4) with a gradient of EtOAc 30 to 60% in hexane. The isolated material (28 mg) was further purified by MDAP to afford 16 mg of the title compound (E16).

Provenance & Evidence