反应详情

To a solution of compound 3 (11.3 g, 43.1 mmol) in anhydrous tetrahydrofuran (400 mL) were added successively, under argon, triphenylphosphine (11.3 g, 43.1 mmol), 2-nitro-3-hydroxypyridine (6.02 g, 43.0 mmol) and dropwise diisopropyl azodicarboxylate (8.70 mL, 44.2 mmol). The mixture was stirred at room temperature for 60 h and the solvent was evaporated under vacuum. Unreacted 2-nitro-3-hydroxypyridine was removed by chromatography (Al2O3., AcOEt/cyclohexane, 9/1, v/v). The residue containing the desired product was dissolved in dichloromethane (200 mL) and pentane (600 mL) was added. The mixture was stirred at room temperature for 5 min and the precipitate was filtered and dried under vacuum to give compound 58 (12.7 g, 33.0 mmol) as a yellow solid. Yield 77%; Rf (Al2O3, AcOEt/cyclohexane, 9/1, v/v) 0.76; mp 124-126° C.; IR (KBr) ν 1274, 1397, 1536, 1702, 1767, 2830 cm−1; 1H NMR (200 MHz, CDCl3) δ 0.96 (t, 3H, J=7.1 Hz), 2.63 (q, 2H, J=7.1 Hz), 2.81 (t, 2H, J=6.4 Hz), 2.94 (t, 2H, J=5.8 Hz), 3.76 (t, 2H, J=6.4 Hz), 4.10 (t, 2H, J=5.8 Hz), 7.50 (m, 2H), 7.60 (m, 2H), 7.75 (m, 2H), 8.05 (dd, 1H, J=2.5, 3.4 Hz); ESI-MS m/z 385.0 [M+H]+.

1. customthe solvent was evaporated under vacuum
2. customwas removed by chromatography (Al2O3
3. additionThe residue containing the desired product
4. dissolutionwas dissolved in dichloromethane (200 mL)
5. additionpentane (600 mL) was added
6. stirringThe mixture was stirred at room temperature for 5 min
7. filtrationthe precipitate was filtered
8. customdried under vacuum