Ammonium Chloride → ethyl (R)-2-tert-butoxycarbonylamino-5-(4-chlorophenyl)-5-oxopentanoate

Participants

Reaction Steps

Under a nitrogen atmosphere, 4-chlorophenyl magnesium bromide (64.1 mL, 1 M tetrahydrofuran solution) was added dropwise at −40° C. into a tetrahydrofuran (300 mL) solution of (R)-5-oxopyrrolidine-1,2-dicarboxylic acid 1-t-butyl ester 2-ethyl ester (15 g) obtained in Example 4. After stirring for 1 hour at the same temperature, saturated ammonium chloride aqueous solution was added, and extraction with ethyl acetate was conducted. After washing the organic layer with brine, the resultant was dried over anhydrous magnesium sulfate. The solvent was removed under a vacuum, and the residue was purified by silica gel column chromatography (heptane→heptane/ethyl acetate), and the title compound (17.38 g) was obtained. The physical property values are as follows.

Provenance & Evidence