Pyridine → allyl (4R)-4-[(2R,3S)-3-{(1R)-1-allyloxycarbonyloxyethyl}-4-oxoazetidin-2-yl]-2-diazo-3-oxopentanoate

To a solution of allyl (4R)-2-diazo-4-[(2R,3S)-3-{(1R)-1-hydroxyethyl}-4-oxoazetidin-2-yl]-3-oxopentanoate (14.6 g) in dichloromethane (100 ml) was added pyridine (6.05 ml) and allyl chloroformate (10.7 ml) at -78° C. The mixture was allowed to warm to ambient temperature and stirred for one day at the same temperature. The reaction mixture was poured into ethyl acetate (100 ml) and water (50 ml), washed in turn with water (50 ml) and brine (50 ml×2), and dried over magnesium sulfate. Evaporation of the solvent gave a residue, which was chromatographed on silica gel (500 ml) eluting with a mixture of hexane and ethyl acetate (1:1 V/V) to give allyl (4R)-4-[(2R,3S)-3-{(1R)-1-allyloxycarbonyloxyethyl}-4-oxoazetidin-2-yl]-2-diazo-3-oxopentanoate (10 g).

1. washwashed in turn with water (50 ml) and brine (50 ml×2)
2. dry with materialdried over magnesium sulfate
3. customEvaporation of the solvent
4. customgave a residue, which
5. customwas chromatographed on silica gel (500 ml)
6. washeluting with a mixture of hexane and ethyl acetate (1:1 V/V)

ORD record

ord-8729cfb8a5b949929ff3458ba5f39432

Source dataset

uspto-grants-1991_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04983596