反应详情

To a solution of 207a (2.39 g, 8.8 mmol), in MeOH (20 ml) was added sodium acetate (0.72 g, 8.8 mmol) and semicarbazide (0.98 g, 8.8 mmol) stirred overnight, concentrated and diluted with CH2Cl2 (100 ml), washed with water, dried and concentrated. Flash chromatography (2% MeOH in CH2Cl2) afforded 208a (2.10 g, 73%) as an oil: [α]D20 −21 (c 2.55°, CH2Cl2); 1H NMR (CDCl3) δ9.98 (1H, s), 7.27 (1H, d), 5.8 (1H, m), 5.5 (1H, d), 5.35-5.19 (2H, m), 4.58 (2H, m), 4.14 (1H, m), 2.37 (2H, t), 2.09 (1H, m), 2.0-1.75 (2H, m); Anal. Calcd for C14H24N4O5: C, 51.21; H, 7.37; N, 17.06. Found: C, 50.2; H, 7.3; N, 16.1.

1. concentrationconcentrated
2. additiondiluted with CH2Cl2 (100 ml)
3. washwashed with water
4. customdried
5. concentrationconcentrated