Metaperiodic acid → HCID 57454787, 화합물

To a solution of crude (2S)-2-[(S)-1-(4-bromophenyl)-2,2,2-trifluoroethylamino]pentan-1-ol (37.1 g, 109 mmol in dry acetonitrile (500 mL) at −78° C. was added a solution of periodic acid (71.7 g) and chromium trioxide (144 mg) in dry acetonitrile (630 mL) over 1 hour. The reaction mixture was allowed to warm to room temperature while stirring overnight. The reaction mixture was concentrated under reduced pressure to a total volume of approximately 500 mL. A solution of citric acid (22 g in 250 mL H2O) was added and the mixture was extracted with ethyl acetate (800 mL). The solution was washed with freshly prepared NaHSO3 (2×200 mL, 25 g solid dissolved to 200 mL with water) brine (300 mL), dried over MgSO4, filtered, and evaporated to give a pale orange solid, which was triturated with 5% ethyl acetate/hexanes to give (2S)-2-[(S)-1-(4-bromophenyl)-2,2,2-trifluoroethylamino]-pentanoic acid. Additional acid was obtained by concentrating the mother liquors, partitioning the residue between ether and aqueous NaHCO3, acidifying the aqueous layer with citric acid, extracting with ethyl acetate, drying over MgSO4, filtering, and evaporating the solvent.