反应详情

Acetylsulfanyl-acetic acid pentafluorophenyl ester (1.6 g, 5.3 mmol) and H-Asp(OtBu)-OH (1 g, 5.3 mmol) were mixed in 20 ml of dry dichloromethane (DCM). Then 1.6 ml of triethylamine (11.5 mmol) was added, and the reaction was allowed to proceed at ambient temperature for 3.5 hours. The organic layer was then extracted with 3×15 ml of 1 M sodium carbonate, the combined aqueous fractions were acidified with 100 ml of 1 M sodium hydrogensulfate and extracted with 3×30 ml ethyl acetate. The combined organic fractions were then rinsed with 30 ml of 1 M sodium hydrogensulfate, 30 ml of 5 M NaCl, dried over sodium sulfate, filtered, and evaporated under reduced pressure to yield 1.97 g of 24 as a nearly colorless syrup which was used without further purification. MW=305 (found 306, M+1).

1. extractionThe organic layer was then extracted with 3×15 ml of 1 M sodium carbonate
2. extractionextracted with 3×30 ml ethyl acetate
3. washThe combined organic fractions were then rinsed with 30 ml of 1 M sodium hydrogensulfate, 30 ml of 5 M NaCl
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. customevaporated under reduced pressure