Trifluoroacetic acid → (3R,6S)-1-(4-Fluoro-benzyl)-3,6-dimethyl-piperazine-2,5-dione

Participants

Reaction Steps

To a solution of (2S)-2-[(2R)-(2-tert-butoxycarbonylamino-propionyl)-(4-fluoro-benzyl)-amino]-propionic acid methyl ester (43 g, 382 mmol) in dichloromethane (120 mL) at 0° C. was added trifluoroacetic acid (60 mL). The reaction was allowed to warm to ambient temperature and stirred for 2 hours. The reaction was cooled to 0° C. and slowly quenched by addition of 3 N sodium hydroxide until basic. The resulting mixture was extracted with dichloromethane. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo to give the title compound (22 g).

Provenance & Evidence