tert-Butanol → tert-butyl (S)-3-(((benzyloxy)carbonyl)amino)-2-((tert-butoxycarbonyl)amino)propanoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To an ice-cold CH2Cl2 (60 mL) solution of DCC (9.78 g, 47.34 mmol), t-BuOH (17.54 g, 0.24 mol) and DMAP (0.29 g, 2.37 mmol); a CH2Cl2 (40 mL) solution of 2 (16.00 g, 47.34 mmol) was added slowly over 20 min. Then reaction mixture was allowed to stir 1 h at 0° C. and 10 h at 20° C. Precipitated urea was then filtered off and the filtrate evaporated in vacuo. The residue was taken up in CH2Cl2, and if necessary, filtered free of any further precipitated urea. The CH2Cl2 solution was washed twice with 10% citric acid solution and with saturated NaHCO3 solution, and then dried over Na2SO4. The residue obtained after evaporation of CH2Cl2 was purified by column chromatography to obtain the product as a clear viscous oil (15.67 g, 84% yield). 1H NMR (300 MHz, CDCl3) δ7.26 (5H), 5.53 (1H), 5.45 (1H), 5.02 (2H), 4.26-4.18 (1H), 3.59-3.46 (2H), 1.38 (9H), 1.37 (9H); 13C NMR (75 MHz, CDCl3) δ 169.9, 156.8, 155.8, 136.6, 128.7, 128.3, 82.8, 80.1, 66.9, 54.7, 43.3, 28.5, 28.1; ESI-LRMS m/z 395.2 (M+H)+, 417.2 (M+Na)+.

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