Water → Rac-5-(4-fluorophenyl)-6-{fluoro[4-(trifluoromethoxy)phenyl]methyl}-7-isopropyl-2,2-dimethyl-2,3-dihydro-4h-chromen-4-one

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Reaction Steps

At −78° C., a solution of 45 μl (340 μmol) of diethylaminosulfur trifluoride in 1 ml of dichloromethane is slowly added dropwise to a solution of 157 mg (310 μmol) of rac-5-(4-fluorophenyl)-6-{hydroxy[4-(trifluoromethoxy)phenyl]methyl}-7-isopropyl-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one (Example 24A) in 4 ml of dichloromethane, and the mixture is stirred at this temperature for 2.5 h. The mixture is then allowed to thaw slowly to −15° C. and stirred for a further 1.5 h. Water is then added, and the mixture is extracted twice with ethyl acetate. The combined organic phases are dried over sodium sulfate and concentrated under reduced pressure. Column chromatography of the residue on silica gel (mobile phase: gradient cyclohexane→cyclohexane/ethyl acetate 10:1→15:1) gives the target compound.

Provenance & Evidence