Betulinic Acid → Boc-Gly betulinic acid

Beteiligte Stoffe

Reaktionsschritte

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.

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