Acetic Anhydride → HCID 20680749, compound

Participants

Reaction Steps

To a solution of 2,2,2-trifluoro-N-[1-(4-nitrobenzyl)-2-oxopyrrolidin-3-(S)-yl]-acetamide (0.75 g, 2.27 mmol) in AcOH (12 mL) is added acetic anhydride (1 mL) and a catalytic amount of 10% palladium on activated carbon. The heterogenous mixture is hydrogenated at room temperature on a Parr apparatus under 70 p.s.i. of H2. After 4.5 h, the reaction mixture is filtered through a pad of Celite, washed with CH2Cl2 and then MeOH. The crude product is concentrated in vacuo to yield 1.2 g of crude N-[1-(4-acetylamino-benzyl)-2-oxopyrrolidin-3-(S)-yl]-2,2,2-trifluoroacetamide as a residue (wet with HOAc). A solution of the crude N-[1-(4-acetylamino-benzyl)-2-oxopyrrolidin-3-(S)-yl]-2,2,2-trifluoroacetamide (1.2 g, wet with AcOH) in AcOH (12 mL) is cooled at 0° C. and acetic anhydride (1 mL) is added. The resulting mixture is treated with a catalytic amount of NaNO2, followed by the dropwise addition of fuming HNO3 (3.8 mL). The reaction mixture is stirred at 0° C. for 1.5 hours, then at room temperature for 1.5 hours. Upon re-cooling to 0° C., a mixture of ice/ice water is added slowly with stirring. The mixture is diluted further with water and extracted with EtOAc (3×50 mL). The combined organic layers are washed twice with water. The organic phase is dried over anhydrous MgSO4, filtered and concentrated. The crude product is purified by column chromatography eluting with a gradient of 25% EtOAc/CH2Cl2 to 50% EtOAc/CH2Cl2 to provide the title compound (0.65 g, 1.67 mmol) as a beige solid.

Provenance & Evidence