Acetic Anhydride → 2-[Cyclopropyl-(4-trifluoromethoxy-benzoyl)-amino]-3-oxo-butyric acid ethyl ester

Participants

Reaction Steps

To a solution of 6.6 ml (1 M in THF, 7 mmol) of lithium hexamethyldisilylazide cooled to −78° C. under Ar was added, drop wise, a solution of 2.0 g (6 mmol) of [cyclopropyl-(4-trifluoromethoxy-benzoyl)-amino]-acetic acid ethyl ester in 10 ml of THF. The mixture was stirred for 1 h before 0.7 g of acetic anhydride was added and the mixture was allowed to reach room temperature. After 2 h the reaction was diluted with EtOAc, washed with saturated ammonium chloride solution, the organic phase dried with sodium sulfate and concentrated. Purification by flash column chromatography [n-heptane/EtOAc 1:9 to 3:7] afforded 0.3 g (13%) of the title compound as a colorless oil. MS: 374.2 (MH+).

Provenance & Evidence