反应详情

To a cooled solution of 2-ethyl-2-hydroxymethyl-butan-1-ol (33.1 g, 250 mmole), 4-dimethylaminopyridine (1.22 g, 10 mmole) and N-benzyloxycarbonyl-L-valine (12.6 g, 50 mmole) in 350 ml dichloromethane was added dropwise a solution of dicyclohexyl-carbodiimide (12.4 g, 60 mmole) in 50 ml dichloromethane. The mixture was stirred 2 days at room temperature and cooled. The urethane was filtered and the solution evaporated under reduced pressure. 350 ml ethyl acetate was added and the organic phase was washed twice with 5% acetic acid, 5% sodium-hydrogencarbonate and water. The organic phase was dried with sodium sulfat and evaporated under reduced pressure. The product was isolated by silica gel column chromatography with dichloromethane/methanol. Yield 16.4 g=90%.

1. temperaturecooled
2. filtrationThe urethane was filtered
3. customthe solution evaporated under reduced pressure
4. addition350 ml ethyl acetate was added
5. washthe organic phase was washed twice with 5% acetic acid, 5% sodium-hydrogencarbonate and water
6. dry with materialThe organic phase was dried with sodium sulfat
7. customevaporated under reduced pressure
8. customThe product was isolated by silica gel column chromatography with dichloromethane/methanol