反应详情

The acid compound 19 (1.0 g, 2.328 mmol) was dissolved in dry DMF and stirred under an atmosphere of argon. N-Methylmorpholine (1.02 mL, 9.32 mmol) was added. After 20 min, hydroxylamine hydrochloride (0.323 g, 4.66 mmol) was added and the reaction mixture was warmed up to room temperature and stirred overnight. The solvent was removed under reduced pressure and residual material was partitioned between EtOAc (50 mL) and saturated NH4Cl solution (1×30 mL). The organic layer was dried and concentrated to yield the crude material. Flash chromatography on SiO2 gel using hexanes-ethyl acetate (70-60%) mixture containing 1% acetic acid furnished the desired hydroxamic acid compound 20 (0.5 g, 98%) 1H NMR (400 MHz, DMSO-d6): 8.47 (br, 1H) 8.14 (dd, J=8.8 and 2.4 Hz, 1H), 7.29 (d, J=8.4 Hz, 2H), 7.11 (d, J=8.8 Hz, 1H), 7.05 (m, 3H), 4.56 (m, 1H), 2.93 (s, 3H) 2.85-2.75 (m, 2H), 2.79 (s, 3H), 1.32 (s, 9H)

1. stirringstirred overnight
2. customThe solvent was removed under reduced pressure and residual material
3. customwas partitioned between EtOAc (50 mL) and saturated NH4Cl solution (1×30 mL)
4. customThe organic layer was dried
5. concentrationconcentrated
6. customto yield the crude material