反应详情

First 22.8 ml of trimethylsilyl chloride and then 25.1 ml of triethylamine were added dropwise to a solution of 43.1 g of (3R,4R)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-acetoxy-2-azetidinone in 450 ml of methylene chloride, maintained at 0° to 5° C. in an ice-water bath. The mixture was stirred at room temperature for 2 hous, then again cooled to 0° to 5° C. in an ice-water bath and filtered under suction. The filtrate was concentrated under reduced pressure. The residue was mixed with 300 ml of anhydrous ether and insolubles were filtered off. The solvent was stripped off from the filtrate, giving 52.8 g of crystalline (3R,4R)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-acetoxy-1-trimethylsilyl-2-azetidinone.

1. temperaturemaintained at 0° to 5° C. in an ice-water bath
2. temperatureagain cooled to 0° to 5° C. in an ice-water bath
3. filtrationfiltered under suction
4. concentrationThe filtrate was concentrated under reduced pressure
5. additionThe residue was mixed with 300 ml of anhydrous ether and insolubles
6. filtrationwere filtered off