反应详情

To a stirred solution of trimethylsilyloxy hydroxylamine (132 μL, 1.08 mmol) and N-methylmorpholine (44 μL, 0.40 mmol) in CH2Cl2 (5 mL) at 0° C. was added dropwise a solution of acid chloride 5 (101 mg, 0.36 mmol) via cannula. The reaction mixture was stirred for 1 h, and then was allowed to warm to rt over 1 h. After being stirred for an additional 1 h, the reaction mixture was diluted with CHCl3: MeOH (20 mL: 1 mL), washed with saturated NaHCO3 solution and then water, and the organic phase was dried (MgSO4) and concentrated under reduced pressure. Purification by flash silica gel chromatography (5-10% MeOH in CHCl3) gave the desired hydroxamic acid 6 (30 mg, 30%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ 7.20 (m, 3H), 6.87 (d, J=7.5 Hz, 2H), 5.60-6.20 (m, 3H), 4.10 (m, 1H), 3.79 (s, 3H), 3.16 (s, 3H), 2.61 (m, 1H), 2.43 (m, 1H); 13C NMR (75.4 MHz, CDCl3) δ 41.6, 55.2, 56.4, 82.7, 113.8, 117.9, 127.8, 130.4, 133.1, 139.3, 141.7, 159.2, 165.5.

1. stirringAfter being stirred for an additional 1 h
2. washMeOH (20 mL: 1 mL), washed with saturated NaHCO3 solution
3. dry with materialwater, and the organic phase was dried (MgSO4)
4. concentrationconcentrated under reduced pressure
5. customPurification by flash silica gel chromatography (5-10% MeOH in CHCl3)