1,2-Dichloroethane → Ethyl 3-((R)-1-benzyl-5-oxopyrrolidine-2-carboxamido)-2-hydroxy-4-phenylbutanoate

Participants

Reaction Steps

To a solution of (R)-1-benzyl-5-oxopyrrolidine-2-carboxylic acid (2440 mg, 11.13 mmol) in a mixture of 24 ml THF and 4 ml DMF were successively added at 5° C. 1-hydroxybenzotriazole (1875 mg, 12.24 mmol), ethyl 3-amino-2-hydroxy-4-phenylbutanoate (2485 mg, 11.13 mmol; preparation described in WO 98/25883, example 8a on page 24), EDC (2347 mg, 12.24 mmol) and DIPEA (6.41 mL; 4750 mg, 36.7 mmol). After stirring overnight at room temperature the reaction mixture was concentrated under reduced pressure, water was added and the obtained mixture was extracted three times with ethyl acetate. The organic layer was washed successively with aq. saturated NaHCO3 (2×), 10% aq. citric acid solution (3×) and brine, dried over Na2SO4 and the solvent was then removed under reduced pressure. The title compound was obtained as a yellow oil (4550 mg, yield: 96%), which was used without further purification in the next step.

Provenance & Evidence