反应详情

Sodium triacetoxyborohydride (5 g, 23.5 mmol) was added to a solution of 2,2-bis(tert-butoxycarbonylamino)-5-oxo-pentanoic acid benzyl ester (3.34 g, 7.9 mmol) and alanine ethyl ester hydrochloride (3.62 g, 23.5 mmol) in dichloromethane (30 mL). After 1 hour saturated ammonium chloride (10 mL) was added and the mixture was stirred for 5 minutes. The aqueous phase was extracted with dichloromethane (2×15 mL), and the combined organic phases were dried over sodium sulfate, filtered and the solvent was removed under reduced pressure. The resulting residue was subjected to flash chromatography with eluent of(10% methanol in ethyl acetate) and hexane. The product-containing fractions were combined and the solvent was removed under reduced pressure to provide 2,2-bis(tert-butoxycarbonylamino)-5-(1-ethoxycarbonyl-ethylamino)-pentanoic acid benzyl ester (1.7 g, 3.3 mmol, 41%). C27H42N2O8 calculated 522.3 observed [M+1]+ 523.3; rt=2.08 min.

1. extractionThe aqueous phase was extracted with dichloromethane (2×15 mL)
2. dry with materialthe combined organic phases were dried over sodium sulfate
3. filtrationfiltered
4. customthe solvent was removed under reduced pressure
5. customthe solvent was removed under reduced pressure