Trifluoroacetic acid → HCID 23121989, 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 (94 mg, 0.30 mmol) in dichloromethane (5 mL) was added trifluoroacetic acid (0.5 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 (50 mL), dried over anhydrous magnesium sulfate and concentrated under reduced pressure. To the residue were added tetrahydrofuran (5 mL) and 4-fluorophenyl isocyanate (0.10 g, 0.73 mmol), and the mixture was stirred at 50° C. for 1 hour. The reaction solution was concentrated, and then the residue was purified with silica gel column chromatography (hexane:ethyl acetate=1:1 to ethyl acetate) to obtain the title compound (20 mg, yield 19%) as a diastereomer mixture. Diastereomer ratio (α:β=3:1).

Provenance & Evidence