4-Methylmorpholine → (2S)-2-[(2R)-(2-Tert-Butoxycarbonylamino-Propionyl)-(4-Fluoro-Benzyl)-Amino]propionic Acid Methyl Ester

Participants

Reaction Steps

To a solution of (R)-2-tert-butoxycarbonylamino-propionic acid (37 g, 195 mmol) in dry tetrahydrofuran (250 mL) at 0° C. was added 4-methyl morpholine (21.5 mL, 195 mmol) followed by isobutylchloroformate (25.3 mL, 195 mmol). The reaction was allowed to warm to ambient temperature and stirred for two hours. This was followed by the addition of (S)-2-(4-fluoro-benzylamino)-propionic acid methyl ester (34.4 g, 162 mmol). The resulting mixture was stirred overnight at ambient temperature. The reaction mixture was filtered through a pad of celite and the filter cake was washed with ethyl acetate. The filtrate was concentrated in vacuo, diluted with ethyl acetate and washed with water and brine. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel gave the title compound (43.2 g).

Provenance & Evidence