反应详情

温度

0 °C

To a 0° C. solution of 2-(S)-tert-butoxycarbonylamino-3-(4-nitrophenyl)-propionic acid, 1, (1.20 g, 4.0 mmol) in THF (20 mL) was added dropwise triethylamine (0.61 mL, 4.4 mmol) followed by iso-butyl chloroformate (0.57 mL, 4.4 mmol). The reaction mixture was stirred at 0° C. for 20 minutes and filtered. The filtrate was treated with an ether solution of diazomethane (˜16 mmol) at 0° C. The reaction mixture was stirred at room temperature for 3 hours then concentrated in vacuo. The resulting residue was dissolved in EtOAc and washed successively with water and brine, dried (Na2SO4), filtered and concentrated. The residue was 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. filtrationfiltered
2. stirringThe reaction mixture was stirred at room temperature for 3 hours
3. concentrationthen concentrated in vacuo
4. dissolutionThe resulting residue was dissolved in EtOAc
5. washwashed successively with water and brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified over silica (hexane/EtOAc 2:1)