反应详情

To a solution of Boc-Gly-OH (525 mg, 3 mmol) in THF (5 ml) was added CDI (486 mg, 3 mmol). The mixture was stirred at room temperature for 2 hours, then betulinic acid (684 mg, 1.5 mmol) was added. The resulting mixture was refluxed overnight. After removal of solvent, the residue was dissolved in dichloromethane, washed with water, followed by brine, and dried over Na2SO4. After removal of solvent, the residue was purified by a column chromatography on silica gel with EtOAc/-hexane as an eluent to give 900 mg of Boc-Gly-betulinic acid derivative (4i). Yield: 97%. m.p.: 135-136° C. 1H NMR (DMSO-d6) δ: 0.75-1.7 (m, 47H), 1.75-1.9 (m, 2H), 2.05-2.3 (m, 2H), 2.9-3.0 (m, 1H), 3.63 (d, J=6 Hz, 2H), 4.4 (m, 1H), 4.56 (d, J=2 Hz, 1H), 4.69 (d, J=2 Hz, 1H), 7.18 (t, J=6 Hz, 1H), 12.05 (s, 1H). MS (ESI−): 612.4 (M-1). FT-IR (cm−1): 2943, 2869, 1702. Anal. Calcd for C37H59N1O6: C, 72.39; H, 9.69; N, 2.28; Found: C, 72.13; H, 10.07; N, 2.20.

1. temperatureThe resulting mixture was refluxed overnight
2. customAfter removal of solvent
3. dissolutionthe residue was dissolved in dichloromethane
4. washwashed with water
5. dry with materialdried over Na2SO4
6. customAfter removal of solvent
7. customthe residue was purified by a column chromatography on silica gel with EtOAc/-hexane as an eluent