反应详情

To a solution of compound 18 (2.0 g, 6 mmol) in THF (30 mL) was added acetic anhydride (4.5 mL, 48 mmol), followed by the addition of Ra—Ni (˜0.4 g), and the mixture was subjected to hydrogenation in a Parr apparatus at 60 psi for 12 h. After filtering over the pad of celite, the solution was concentrated to get a brown oil material, which was resolved over silica column eluting with EtOAc:hexanes (4:6) and then changing to (6:4) to get 1.75 g (75%) of 19 as an off-white gum. IR (KBr) νmax. cm′: 3311, 3160 (NH), 3062 (Ar—H), 1691 (C═O), 1611, 1512, 1412 (C═C). 1H NMR (500 MHz, CDCl3) δ=1.39 (s, 9H, (CH3)3C); 1.98 (s, 3H, CH3); 2.21 (s, 3H, CH3); 3.03 (m, 4H, 2CH2); 3.53 (m, 4H, 2CH2); 4.29 (d, 2H, J=6.7 Hz, CH2); 6.73 (d, 1H, J=2.4 Hz, H-2); 6.84 (dd, 1H, J=8.8, J=2.4 Hz, H-6); 7.85 (d, 1H, J=8.8 Hz, H-5); 9.48 (s, 1H, NH); 13C NMR (125.7 MHz, CDCl3) δ=22.96 (CH3), 24.06 (CH3), 28.37 (CH3)3C), 40.87 (CH2), 43.50 (CH2), 49.73 (CH2), 79.95 (CH3)3C), 117.14 (C-2), 118.65 (C-4), 124.56 (C-6), 129.59 (C-3), 129.94 (C-5), 147.95 (C-1), 154.67 (C═O), 169.41 (C═O), 171.29 (C═O). Calculated (%) for C20H30N4O4 (390.23); C: 61.52, H: 7.74, N: 14.35. found (%); C: 61.43, H: 7.82, N: 14.26.

1. filtrationAfter filtering over the pad of celite
2. concentrationthe solution was concentrated
3. customto get a brown oil material, which
4. washeluting with EtOAc:hexanes (4:6)