反应详情

To a solution of (2S,4R)-1-benzyloxycarbonyl-2-carboxymethyloxymethyl-4-methanesulfonyloxypyrrolidine (3.80 g) in benzene (19 ml) was added thionyl chloride (0.90 ml) with stirring at ambient temperature and the mixture was stirred at the same temperature for one hour. To the mixture were added urea (1.80 g) and concentrated sulfuric acid (0.05 ml) successively. The mixture was heated under reflux for 5 hours. The reaction mixture was poured into ice-water (100 ml) and extracted with ethyl acetate (100 ml). The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (100 g) and eluted with a mixture of methanol and chloroform (1:99 V/V) to give (2S,4R)-1-benzyloxycarbonyl-4-methanesulfonyloxy-2-[(ureidocarbonylmethyl)oxymethyl]pyrrolidine (1.85 g).

1. stirringthe mixture was stirred at the same temperature for one hour
2. temperatureThe mixture was heated
3. temperatureunder reflux for 5 hours
4. extractionextracted with ethyl acetate (100 ml)
5. dry with materialThe organic layer was dried over magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. customto give a syrup
8. washeluted with a mixture of methanol and chloroform (1:99 V/V)