Water → 3-[[(S)-2-[[(1,1-Dimethylethoxy)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]propanoic acid, phenylmethyl ester

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Reaction Steps

Boc-L-phenylalanine (1.32 g, 5.00 mmol) was dissolved in dichloromethane (50 mL) and treated with HoBt.H2O (1.53 g, 2.00 mmol) followed by WSCDI (water soluble carbodiimide) (1.00 g, 5.24 mmol). After stirring for 40 minutes, β-alanine benzyl ester tosylate (1.85 g, 5.27 mmol) was added, followed by DIPEA (diisopropylethylamine) (1.29 g, 10 mmol). Stirring was continued overnight, then the solvent removed. The residue was dissolved in ethyl acetate (30 mL) and washed with water, 10% sodium bicarbonate solution, then 10% citric acid solution. The organic layer was dried (MgSO4) and evaporated to a white solid--a single component by TLC, 1.74 g, 82% of (32). NMR (CDCl3) δ 1.41 (9H, s), 2.47 (2H, m), 3.01 (2H, m), 3.45 (2H, m), 4.25 (1H, br.q), 5.00 (1H, br.s), 5.07 (2H, s), 6.21 (1H, br.t), 7.15-7.38 (10H, m).

Provenance & Evidence