反应详情

温度

-20 °C

To a solution of 2.26 g. (11 mmole) of N-t-butoxycarbonyl-D-serine in 75 ml. of tetrahydrofuran is added 1.47 ml. (10 mmole) of triethylamine and the mixture cooled to -10° C. At this temperature is added 0.96 ml. (10 mmole) of ethyl chloroformate and stirring continued for 15 minutes. After cooling to -20° C., 1.6 g. (10 mmole) of dl-3-amino-2,2,4,4-tetramethyltetrahydrothiophene is added and the resulting mixture is allowed to warm to room temperature. Ethyl acetate is added and the mixture is washed twice with 50 ml. portions of 5% (by weight) aqueous citric acid, aqueous sodium bicarbonate (1×50 ml.) and saturated brine (1×50 ml.). The organic layer is dried (Na2SO4) and evaporated to dryness at reduced pressure to afford N(2,2,4,4-tetramethyltetrahydrothiophene-3-yl)-t-butoxycarbonyl-D-serine amide. This product is used without further purification in the next step. ##STR120##

1. additionAt this temperature is added 0.96 ml
2. temperatureto warm to room temperature
3. washthe mixture is washed twice with 50 ml
4. dry with materialThe organic layer is dried (Na2SO4)
5. customevaporated to dryness at reduced pressure