反应详情

温度

-70 °C

5.51 g (20 mmol) of dimethyl Boc-glutamate were dissolved in 60 ml of tetrahydrofuran and cooled to −70° C. Over a period of one hour, 44 ml (44 mmol) of a 1M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise at this temperature, and the mixture was stirred at −70° C. for 2 hours. 18.60 g (60 mmol) of 1,4-diiodobutane were then added dropwise, and after 2 h at this temperature the cooling bath is removed and 100 ml of 2N hydrochloric acid and 300 ml of ethyl acetate were added. The organic phase was separated off, washed with water until neutral, dried over sodium sulphate and filtered, and the filtrate was concentrated. The crude product obtained in this manner was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.

1. customafter 2 h at this temperature the cooling bath is removed
2. addition100 ml of 2N hydrochloric acid and 300 ml of ethyl acetate were added
3. customThe organic phase was separated off
4. washwashed with water until neutral,
5. dry with materialdried over sodium sulphate
6. filtrationfiltered
7. concentrationthe filtrate was concentrated