反应详情

Triethylamine (2.22 g; 22.0 mmol) was added dropwise to a stirred solution of 5-(Boc-amino)-4-oxopentanoic acid (4.62 g; 20.0 mmol) and t-butyl bromoacetate (4.30 g; 22.0 mmol) in ethyl acetate (60 mL) under argon at ambient temperature. The mixture (slurry) was refluxed for 17 h, then cooled to ambient temperature, poured into 0.5 M HCl (100 mL) and shaken thoroughly. The aqueous portion was extracted with ethyl acetate (2×20 mL). The combined organic solutions were washed with saturated NaHCO3 solution (1×20 mL) and saturated NaCl solution (1×20 mL) then dried (MgSO4), filtered and evaporated. Evaporation resulted in an amber oil that was purified by flash chromatography on a 40×55-mm silica gel 60 column eluted with ethyl acetate-hexane (1:1) (600 mL), collecting 5×100 mL fractions. Evaporation of fractions 1 and 2 resulted in 6.15 g (89%) product (yellow oil).

1. temperatureThe mixture (slurry) was refluxed for 17 h
2. extractionThe aqueous portion was extracted with ethyl acetate (2×20 mL)
3. washThe combined organic solutions were washed with saturated NaHCO3 solution (1×20 mL) and saturated NaCl solution (1×20 mL)
4. dry with materialthen dried (MgSO4)
5. filtrationfiltered
6. customevaporated
7. customEvaporation
8. customresulted in an amber oil that
9. customwas purified by flash chromatography on a 40×55-mm silica gel 60 column
10. washeluted with ethyl acetate-hexane (1:1) (600 mL)
11. customcollecting 5×100 mL fractions
12. customEvaporation of fractions 1 and 2