Diisopropylethylamine → (S)-4-tert-butoxycarbonylamino-4-(4-cyano-benzylcarbamoyl)-butyric acid benzyl ester

Participants

Reaction Steps

A solution of Boc-Glu(OBzl)-OH (7.08 g, 21.0 mmol), BOP (9.72 g, 22.0 mmol) and DIEA (12.18 ml, 70.0 mmol) in DMF (50 ml) was maintained at room temperature for 20 min, followed by the addition of 4-(aminomethyl)benzonitrile hydrochloride (3.38 g, 20.0 mmol). The reaction mixture was stirred at room temperature for an additional 1 h and diluted with EtOAc (500 ml). The obtained solution was extracted with water (100 ml), 5% aq. NaHCO3 (100 ml) and water (2×100 ml). The organic layer was dried over MgSO4, evaporated and dried in vacuo to provide compound HH (9.65 g, yield exceeded quantitative) as yellowish oil. LC-MS [M+H] 452.0 (C25H29N3O5+H, calc: 452.4). Compound HH was used without further purification.

Provenance & Evidence