1,2-Dichloroethane → (S)-2-[(S)-2-(tert-butoxycarbonyl-methyl-amino)-propionylamino]-3-methyl-butyric acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-2-(tert-butoxycarbonyl(methyl)amino)propanoic acid (4.06 g, 20.0 mmol, Eq: 1), HOAT (4.08 g, 30.0 mmol, Eq: 1.5) and EDC (5.74 g, 30.0 mmol, Eq: 1.5) in DCM (200 mL), was added a solution of (S)-benzyl 2-amino-3-methylbutanoate hydrochloride (5.35 g, 22.0 mmol, Eq: 1.1) and N-methylmorpholine (4.45 g, 4.83 mL, 43.9 mmol, Eq: 2.2) in 50 mL of DCM. The reaction mixture was stirred at 23° C. for 3 h. The clear yellow solution was concentrated in vacuo. The residue was taken up in EtOAc and washed with saturated aqueous NaHCO3 (1×300 mL), 5% aqueous KHSO4 and brine (1×300 mL). The organic layer was dried over Na2SO4 and concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, 0% to 80% EtOAc in hexanes) to afford (S)-2-[(S)-2-(tert-butoxycarbonyl-methyl-amino)-propionylamino]-3-methyl-butyric acid benzyl ester as a colorless oil (7.02 g), m/z=393 (M+H).

Provenance & Evidence