Sodium Bicarbonate → Rac-5-(4-fluorophenyl)-6-{hydroxy[4-(trifluoromethyl)phenyl]methyl}-7-isopropyl-2,2-dimethyl-2,3-dihydro-4h-chromen-4-one

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Reaction Steps

At −78° C., 2.29 ml (1.15 mmol) of a freshly prepared 0.5 M solution of bromo[4-(trifluoromethyl)phenyl]magnesium in tetrahydrofuran are slowly added dropwise to a solution of 300 mg (881 μmol) of 5-(4-fluorophenyl)-7-isopropyl-2,2-dimethyl-4-oxochroman-6-carbaldehyde (Example 20A) in 7 ml of tetrahydrofuran. The mixture is then allowed to thaw slowly to −20° C. and stirred at this temperature for 45 min. A 10% strength sodium bicarbonate solution is then added, the mixture is extracted three times with ethyl acetate and the combined organic phases are washed with saturated sodium chloride solution. The organic phases are dried over magnesium sulfate, the solvent is then removed under reduced pressure and the residue is purified by column chromatography on silica gel (mobile phase: gradient cyclohexane→cyclohexane/ethyl acetate 10:1).

Provenance & Evidence