4-Methylmorpholine → [(R)-1-(3,5-Dichloro-4-fluoro-phenylcarbamoyl)-ethyl]-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a cooled (−20° C.) solution of (R)-2-tert-butoxycarbonylamino-propionic acid (57.2 g, 302 mmol) in anhydrous THF (582 mL) was added N-methyl-morpholine (34.9 mL, 317 mmol) at a rate to keep the internal temperature at −15° C. Isobutyl chloroformate (42.0 mL, 317 mmol) was then added over a 20 min period and the resulting mixture was stirred for 30 min. A solution of 3,5-dichloro-4-fluoro-phenylamine (54.4 g, 302 mmol) in THF (160 mL) was then added over 40 min. The reaction mixture was warmed to 20° C. and stirred for 20 h. The reaction mixture was filtered and concentrated in vacuo. To the resulting oil was added MeOH (200 mL) and the solution was concentrated to provide the title compound as a tan colored solid, m/z 295.3 [M-t-Bu]+. This material was used without further purification.

Provenance & Evidence