反应详情

温度

60 °C

23.5 ml (305 mmol) of methyl chloroformate are added over a period of 20 min to a solution of 20 g (152 mmol) of (L)-tert-leucine (=2(S)-amino-3,3-dimethyl-butyric acid=(L)-α-tert-butylglycine; Fluka, Buchs/Switzerland) in a mixture of 252 ml (504 mmol) of 2N aqueous sodium hydroxide solution and 80 ml of dioxane and the reaction solution is heated at 60° C. for 14 hours. After cooling to room temperature, the reaction solution is washed 2× with methylene chloride. The aqueous phase is acidified to pH 2 with 4N aqueous hydrochloric acid and extracted three times with ethyl acetate. The organic extracts are combined, dried (Na2SO4) and concentrated by evaporation, the product beginning to solidify. Digestion of the solidified solid with hexane yields the title compound in the form of a white powder. M.p. 106-108° C.

1. temperatureAfter cooling to room temperature
2. washthe reaction solution is washed 2× with methylene chloride
3. extractionextracted three times with ethyl acetate
4. dry with materialdried (Na2SO4)
5. concentrationconcentrated by evaporation