Tetrahydrofuran → (R)-2-[(3S,4S)-3-[(R)-1-(tert-Butyldimethylsilyloxy)ethyl]-2-oxoazetidin-4-yl]propionic acid

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Reaction Steps

To a tetrahydrofuran solution (2:1, 3.5 ml) of 3-{(2R)-2-[(3S,4R)-3-[(1R)-1-tert-butyldimethylsilyloxyethyl]-2-oxoazetidin-4-yl]propionyl}-N-cyclohexyl-p-toluenesulfonamide (218 mg, 0.4 mmol, β:α=88:12), 0.5N aqueous sodium hydroxide (1.8 ml) was added dropwise at room temperature, followed by stirring for 3 hours at the same temperature. To the reaction mixture, 5 ml of water was then poured and the resulting mixture was washed with methylene chloride. The aqueous layer was acidified to pH 2 with 2N-hydrochloric acid. The crystals so precipitated were collected by filtration, washed with water, and then dried under reduced pressure, whereby 84 mg (β:α=89:11) of the colorless title compound was obtained (yield: 69%).

Provenance & Evidence