反应详情

A mixture of 205a (2.75 g, 7.5 mmol), formaldehyde (37 percent in water, 30 ml, 375 mmol), NaBH(OAc)3 (4.75 g, 22.5 mmol) and acetic acid (25 ml, 150 mmol) in methanol (125 ml) was stirred for 4 hours at room temperature. The mixture was then brought to basic condition with saturated NaOH solution and extracted with ethyl acetate. The organic layer was dried over Na2SO4 and evaporated under reduced pressure. The residue was purified by column chromatography eluting with 4:1 ethyle acetate/methanol to give 205b (2.0 g, 77%). LC/MS: m/z 349 (M+H)+

1. extractionextracted with ethyl acetate
2. dry with materialThe organic layer was dried over Na2SO4
3. customevaporated under reduced pressure
4. customThe residue was purified by column chromatography
5. washeluting with 4:1 ethyle acetate/methanol