反应详情

温度

0 °C

A solution of 8.7 g (25 millimoles) of (S)-2,3-bis-(benzoylthio)-propionic acid and 4.8 g (25 millimoles) of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride in 125 ml of a 4:1 mixture of tetrahydrofuran and water was added to 4.4 g (25 millimoles) of tert.-butyl proline (crude product, obtained by hydrogenation of 7.6 g of tert.-butyl Z-proline) in 100 ml of tetrahydrofuran, while cooling at 0° C. The mixture was stirred for 1 hour at 0° C. and then for 1 hour at 20° C., after which it was partitioned between ethyl acetate and water by shaking, and the organic phase was dried with anhydrous sodium sulfate and evaporated down under reduced pressure. Chromatography with 2:1 cyclohexane/ethyl acetate over a column containing deactivated silica gel gave 9.0 g (72%) of tert.-butyl N-[(S)-2,3-bis-(benzoylthio)-propionyl]-proline. The crude product was dissolved in 50 ml of dry dioxane, 50 ml of 6N HCl/dioxane were added and the mixture was left to stand for 1 hour at 20° C. It was partitioned between ethyl acetate and water by shaking, the organic phase was washed twice with water, dried with anhydrous sodium sulfate and evaporated down under reduced pressure and 7.8 g (70%) of N-[(S)-2,3-bis-(benzoylthio)-propionyl]-proline, melting point 155°-158° C. (cyclohexane/ethyl acetate), Rf=0.56 in system I, [α]D20 =+76° (c=1 in chloroform), were obtained.

1. waitfor 1 hour at 20° C.
2. customafter which it was partitioned between ethyl acetate and water
3. stirringby shaking
4. dry with materialthe organic phase was dried with anhydrous sodium sulfate
5. customevaporated down under reduced pressure
6. additionChromatography with 2:1 cyclohexane/ethyl acetate over a column containing deactivated silica gel