反应详情

To a mixture of 4-hydroxybenzoic acid (16) (0.424 g, 3.07 mmol), O-benzylhydroxylamine hydrochloride (0.490 g, 3.07 mmol), and 4-dimethylaminopyridine (0.414 g, 3.39 mmol) in dichloromethane (30 ml) under argon atmosphere 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.643 g, 3.35 mmol) was added and the resultant mixture was stirred at room temperature for 5 hours. The reaction mixture was poured into a mixture of saturated NaH2PO4 (30 ml) and water (70 ml), and extracted with ethyl acetate (2×75 ml). The extract was washed with a mixture of saturated NaH2PO4 (15 ml) and water (35 ml), brine (50 ml), and dried (MgSO4). The solvent was evaporated and the residue was chromatographed on silica gel (50 g) with benzene-ethyl acetate-acetic acid (75:25:1, 100 ml) and benzene-ethyl acetate-acetic acid (50:50:1, 300 ml) as eluents to give the title compound (0.338 g, 45%) as a white solid. 1H NMR (DMSO-d6, HMDSO), δ: 4.88 (2H, s); 6.79 (2H, d, J=8.8 Hz); 7.23-7.55 (5H, m); 7.59 (2H, d, J=8.8 Hz); 10.02 (1H, br s); 11.48 (1H, s).

1. additionwas added
2. extractionextracted with ethyl acetate (2×75 ml)
3. washThe extract was washed with a mixture of saturated NaH2PO4 (15 ml) and water (35 ml), brine (50 ml)
4. dry with materialdried (MgSO4)
5. customThe solvent was evaporated
6. customthe residue was chromatographed on silica gel (50 g) with benzene-ethyl acetate-acetic acid (75:25:1, 100 ml) and benzene-ethyl acetate-acetic acid (50:50:1, 300 ml) as eluents