反应详情

温度

0 °C

To a 0° C. solution of 2-(S)-tert-butoxycarbonylamino-3-(4-nitrophenyl)-propionic acid (1.20 g, 4.0 mmol) in THF (20 mL) is added dropwise triethylamine (0.61 mL, 4.4 mmol) followed by iso-butyl chloroformate (0.57 mL, 4.4 mmol). The reaction mixture is stirred at 0° C. for 20 minutes then filtered. The filtrate is treated with an ether solution of diazomethane (˜16 mmol) at 0° C. The reaction mixture is stirred at room temperature for 3 hours and concentrated. The residue is dissolved in EtOAc and washed successively with water and brine, dried (Na2SO4), filtered and concentrated in vacuo. The resulting residue is purified over silica (hexane/EtOAc 2:1) to afford 1.1 g (82% yield) of the desired product as a slightly yellow solid. 1H NMR (300 MHz, CDCl3) δ 8.16 (d, J=8.7 Hz, 2H), 7.39 (d, J=8.7 Hz, 2H), 5.39 (s, 1H), 5.16 (d, J=6.3 Hz, 1H), 4.49 (s, 1H), 3.25 (dd, J=13.8 and 6.6, 1H), 3.06 (dd, J=13.5 and 6.9 Hz, 1H), 1.41 (s, 9H).

1. filtrationthen filtered
2. stirringThe reaction mixture is stirred at room temperature for 3 hours
3. concentrationconcentrated
4. dissolutionThe residue is dissolved in EtOAc
5. washwashed successively with water and brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customThe resulting residue is purified over silica (hexane/EtOAc 2:1)