反应详情

温度

0 °C

(2R)-2-(tert-butoxycarbonylamino)butanoic acid (5 g, 24.60 mmol) was dissolved in DCM (500 mL) and cooled to 0° C. CDI (4.188 g, 25.83 mmol) was added and the reaction stirred for 60 minutes. Formic hydrazine (1.477 g, 24.60 mmol) was added and the reaction stirred at 0° C. for 45 minutes then allowed to reach ambient temperature overnight. The reaction was cooled to 0° C. and treated with PS-PPh3 (22.88 g, 49.20 mmol) and CBr4 (16.32 g, 49.20 mmol) The reaction was allowed to warm slowly to ambient temperature over 2 hours, filtered and concentrated under reduced pressure. The residue was purified by column chromatography (25 to 50% EtOAc/Petrol) to give the sub-title compound as a colourless oil (2.30 g, 41%); 1H NMR (400.0 MHz, DMSO) d 0.88 (t, 3H), 1.27-1.39 (2×s, 9H), 1.75-1.87 (m, 2H), 4.71 (dd, 1H), 7.62 (d, 1H), 9.17 (s, 1H) MS ES(+) 228.

1. stirringthe reaction stirred at 0° C. for 45 minutes
2. waitto reach ambient temperature overnight
3. temperatureThe reaction was cooled to 0° C.
4. temperatureto warm slowly to ambient temperature over 2 hours
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by column chromatography (25 to 50% EtOAc/Petrol)