Boron tribromide → 6-[2-(2-Chloro-5-hydroxy-phenyl)-1-hydroxy-1-trifluoromethyl-propyl]-4-methyl-4H-benzo[1,4]oxazin-3-one

Participants

Reaction Conditions

Reaction Steps

A solution of 6-[2-(2-chloro-5-methoxy-phenyl)-1-hydroxy-1-trifluoromethyl-propyl]-4-methyl-4H-benzo[1,4]oxazin-3-one (553 mg) in dichloromethane (13 ml) was cooled to −70° C. A 1 M solution of boron tribromide in dichloromethane (5.14 ml) was added and the mixture was stirred at −70° C. for 1.5 h and at 0° C. for 1 h. A mixture of ice water and saturated aqueous NaHCO3 solution was added and the mixture was extracted with dichloromethane. The organic phase was washed with water and dried (MgSO4). The product was purified by chromatography (SiO2, cyclohexane/EtOAc 9:1=>2:3) to give the title compound (542 mg) as off-white foam. MS (m/e, ISP neg. ion)=414.0 [M−H+].

Provenance & Evidence