Sodium borohydride → 5-(4-Chlorophenyl)-6-(2,4-dichlorophenyl)-2-(3,4-difluorophenyl)-furo[2,3-b]pyridin-3-ol

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Reaction Steps

To a solution of 80 mg (0.14 mmol) of the product of Step B dissolved in 1 mL EtOH was added 9 mg (0.20 mmol) of sodium borohydride. The reaction mixture was stirred at RT for 5 min then partitioned between EtOAc and water. The organic layer was separated, dried (MgSO4), filtered and evaporated. The residue was then redissolved in 10 mL MeOH and 2 mL of a 2.0 N solution of sodium hydroxide was added. The reaction mixture was stirred at 80° C. for 0.5 h, then cooled to room temperature and partitioned between EtOAc and 10% aq. NaHSO4. The organic layer was separated, washed with water, dried (MgSO4), filtered and evaporated. The residue was purified on a silica gel flash chromatography column eluted with 0–20% EtOAc-hexane. Combination of the purified fractions and drying in vacuo afforded the title compound.

Provenance & Evidence