[O:1]([C:5]1[CH:10]=[CH:9][C:8]([N+:11]([O-])=O)=[CH:7][N:6]=1)[CH:2]([CH3:4])[CH3:3]>C(O)(=O)C.CCOC(C)=O.[Fe]>[O:1]([C:5]1[CH:10]=[CH:9][C:8]([NH2:11])=[CH:7][N:6]=1)[CH:2]([CH3:4])[CH3:3]A 100 mL round-bottom flask was charged with the iron powder (5.6 g, 10 mmol) in acetic acid (30 mL) and heated to 80° C. (oil bath) under N2. To this mixture was added slowly the above 2-isopropoxyl-5-nitropyridine (4.6 g, 25.2 mmol) in acetic acid (30 mL) via dropping funnel and the reaction stirred at 80° C. for another 30 min after the addition. After cooling the reaction mixture, it was diluted with EtOAc, filtered through celite, and the solvent evaporated in vacuo. The residue was dissolved in EtOAc and washed with NaHCO3 (sat.), brine, dried over MgSO4, and concentrated under reduced pressure. The residue was purified through automated normal-phase chromatography to afford 2-isopropoxyl-5-aminopyridine (3.8 g, 99%) which was used directly for the next step: 1H NMR (400 MHz, CDCl3) δ 7.64 (d, 1 H), 7.00 (dt, 1 H), 6.52 (d, 1 H), 5.10 (sep, 1 H), 1.30 (d, 6H); MS (ES) (M++H) expect 153.1, found 153.1.
Wird geladen…
