反应详情

温度

0 °C

To a cooled solution of (S)-2-tert-butoxycarbonylamino-3-phenylpropionic acid (available from Aldrich; 5.3 g, 20 mmol) in dimethylformamide (50 mL) at 0° C. were added 1-hydroxybenzotriazole (available from 3B Scientific Corporation, Libertyville, Ill. 60048, USA; 2.97 g, 22 mmol) and O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluororophosphate (available from Aldrich; 8.30 g, 22 mmol). Diisopropylethylamine (10.7 mL, 61.4 mmol) and dimethylamine in tetrahydrofuran (2M, 15 mL, 30 mmol) were added dropwise. The mixture was stirred for 1 h at 0° C. and ethyl acetate was added. The mixture was washed with water and brine, and dried over sodium sulfate. Evaporation of the solvents gave ((S)-1-dimethylcarbamoyl-2-phenyl-ethyl)-carbamic acid tert-butyl ester as a yellow oil (5.52 g) which was used in the next step without further purification.

1. washThe mixture was washed with water and brine
2. dry with materialdried over sodium sulfate
3. customEvaporation of the solvents