反应详情

2,4,6-Trimethoxybenzaldehyde (12.42 g, 63.3 mmol) and O-benzylhydroxylamine (7.80 g, 63.3 mmol) were stirred in dichloromethane (65 mL) at rt overnight. The solvent was removed under reduced pressure. The crude residue was dissolved in ethanol (550 mL) and sodium cyanoborohydride (12.0 g, 189.9 mmol) was added dropwise. The mixture was stirred for 5-10 min, then 12 N HCl was added dropwise until pH became below 3. The reaction mixture was stirred for additional 3 h and 1 N NaOH was added until pH>8. The product was extracted with dichloromethane. The organic phase was dried over Na2SO4 and concentrated under vacuo. The residue was purified by flash chromatography (5% ether in dichloromethane) to give 15.9 g of O-benzyl-N-(2,4,6-trimethoxy-benzyl)hydroxylamine as an oil (83% yield).

1. customThe solvent was removed under reduced pressure
2. dissolutionThe crude residue was dissolved in ethanol (550 mL)
3. stirringThe reaction mixture was stirred for additional 3 h
4. extractionThe product was extracted with dichloromethane
5. dry with materialThe organic phase was dried over Na2SO4
6. concentrationconcentrated under vacuo
7. customThe residue was purified by flash chromatography (5% ether in dichloromethane)