Trifluoroacetic acid → HCID 23121942, compound

Participants

Reaction Steps

To a solution of 1,1-dimethylethyl tetrahydro-3-oxo-1-phenyl-3H-oxazolo[3,4-a]pyrazine-7(1H)-carboxylate (0.12 g, 0.38 mmol) in dichloromethane (5 mL) was added trifluoroacetic acid (1 mL), and the mixture was stirred at room temperature for 4 hours. The reaction solution was concentrated, and then ethyl acetate was added to the residue. The resulting mixture was washed with a 0.5 M aqueous sodium hydrogen carbonate solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. To the residue were added tetrahydrofuran (5 mL), triethylamine (0.10 ml, 0.75 mmol) and phenyl chlorocarbonate (88 mg, 0.56 mmol), and the mixture was stirred at room temperature for 2 hours. To the reaction solution was added ethyl acetate, and the resulting mixture was washed with a 0.5 M aqueous sodium hydrogen carbonate solution, dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified with silica gel column chromatography (hexane:ethyl acetate=9:1 to ethyl acetate) to obtain the title compound (0.10 g, yield 80%) as a diastereomer mixture. Diastereomer ratio (α:β=3:1).

Provenance & Evidence