4-Methylmorpholine → (R)-N-Benzyloxycarbonyl-alpha-{N-[(S)-1-(t-butoxycarbonyl)propyl]carbamoyl}-4-hydroxybenzylamine

Participants

Reaction Steps

A solution of (R)-N-benzyloxycarbonyl-α-carboxy-4-hydroxybenzylamine (Method 17; 2.00 g, 6.64 mmol), (2S)-2-amino butanoic acid t-butyl ester (1.30 g, 6.64 mmol) and N-methylmorpholine (2.0 g, 19.8 mmol) in DCM (30 ml) was stirred at RT for 5 min, after which TBTU (2.60 g, 8.10 mmol) was added. The reaction mixture was stirred at ambient temperature overnight. The solvent was removed under reduced pressure and the residue was purified by flash chromatography on silica gel DCM:Acetone—60:40). The product was crystallized from toluene (20 ml) giving 1.85 g of the desired product as a white solid. NMR (400 MHz): 0.80 (3H, t), 1.45 (9H, s), 1.50–1.80 (2H, m), 4.10–4.20 (1H, m), 5.05 (1H, d(AB)), 5.15 (1H, d(AB)), 6.75 (2H, d), 7.20–7.40 (7H, m).

Provenance & Evidence