反应详情

To a solution of 3-[(R)-2-[(3S,4R)-3-[(R)-1-tert-butyldimethylsilyloxyethyl]-2-oxoazetidin-4-yl]propionyl]-2,3-dihydro-2,2-dimethyl-4H-1,3-benzoxazin-4-one (7.0 g, 15 mmol) in a solvent mixture of methanol/water (2:1, 45 ml), a 30% aqueous solution of hydrogen peroxide (3.5 g, 30 mmol) was added at room temperature. Then a 28% aqueous solution of sodium hydroxide (2.4 g, 17 mmol) was added dropwise into it and the obtained mixture was stirred until the starting material disappeared in HPLC. After the completion of the reaction, 45 ml of cold water was added to the reaction mixture. After washing with 15 ml of methylene chloride, 35% hydrochloric acid was added to thereby adjust the pH value of the mixture to 3. The crystals thus precipitated were collected by filtration, washed with water and dried. Thus 4.3 g of (R)-2-[(3S,4S)-3-[(R)-1-tert-butyldimethylsilyloxyethyl]-2-oxoazetidin-4-yl]propionic acid was obtained.

1. additionwas added to the reaction mixture
2. washAfter washing with 15 ml of methylene chloride, 35% hydrochloric acid
3. additionwas added
4. customThe crystals thus precipitated
5. filtrationwere collected by filtration
6. washwashed with water
7. customdried