反应详情

A mechanically stirred solution of 4-tert-butoxycarbonylamino-3-oxo-5-phenyl-pentanoic acid ethyl ester (115 g, 0.343 mol) in ethanol (450 ml) at 0° C. under nitrogen was treated portionwise with sodium borohydride (4.43 g, 0,117 mol) over 30 minutes, producing a thick slurry. The reaction mixture was quenched by the dropwise addition of glacial acetic acid (26 ml) at 0° C. under nitrogen. The slurry was then poured onto a mixture of dichloromethane (400 ml) and a 1M aqueous hydrogen chloride solution (400 ml) in a separating funnel. The organic layer was removed and the aqueous solution extracted with dichloromethane (180 ml). The combined organic solutions were washed sequentially with water (200 ml), 5% aqueous sodium hydrogen carbonate solution (200 ml) and brine (200 ml, and dried (anhydrous magnesium sulfate). The solvents were removed in vacuo to give an off-white solid which was recrystallised from methylcyclohexane/ethyl acetate providing 4-tert-butoxycarbonylamino-3-hydroxy-5-phenyl-pentanoic acid ethyl ester (77 g, 66%).

1. customproducing a thick slurry
2. customThe reaction mixture was quenched by the dropwise addition of glacial acetic acid (26 ml) at 0° C. under nitrogen
3. additionThe slurry was then poured onto a mixture of dichloromethane (400 ml)
4. customThe organic layer was removed
5. extractionthe aqueous solution extracted with dichloromethane (180 ml)
6. washThe combined organic solutions were washed sequentially with water (200 ml), 5% aqueous sodium hydrogen carbonate solution (200 ml) and brine (200 ml
7. dry with materialdried (anhydrous magnesium sulfate)
8. customThe solvents were removed in vacuo
9. customto give an off-white solid which
10. customwas recrystallised from methylcyclohexane/ethyl acetate