反应详情

To a solution of ethyl-L-norvalinate (IV, 62 g, 0.427 moles) in acetonitrile (300 ml) were added successively benzyl-(R)-2-bromo-propionate (V1, 20 g, 0.0822 moles) and triethyl amine (28 ml, 0.2016 moles). The reaction mixture was refluxed for 7-8 hrs. The excess solvent was removed by distillation under reduced pressure to afford a thick oil. The oil was dissolved in a mixture of diisopropyl ether (80 ml) and water (40 ml). The organic phase was extracted in 10% hydrochloric acid solution (40 ml×2). The combined acidic extracts were made alkaline by addition of an aqueous solution of sodium carbonate. The aqueous phase was again extracted with diisopropyl ether (200 ml×2). The combined organic layer was concentrated under reduced pressure to afford 103 g of the title compound as an oil.

1. temperatureThe reaction mixture was refluxed for 7-8 hrs
2. customThe excess solvent was removed by distillation under reduced pressure
3. customto afford a thick oil
4. extractionThe organic phase was extracted in 10% hydrochloric acid solution (40 ml×2)
5. additionby addition of an aqueous solution of sodium carbonate
6. extractionThe aqueous phase was again extracted with diisopropyl ether (200 ml×2)
7. concentrationThe combined organic layer was concentrated under reduced pressure