Chlorine → HCID 56614704, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of a mixture (1:3) of methyl 3-methyl-2-[(3S,4R)-4-methylthio-3-{(1RS)-1-(p-nitrobenzyloxycarbonyloxy)ethyl}-2-oxoazetidin-1-yl]-but-2-enoate (1.30 g) in dichloromethane (13 ml) was added a solution of chlorine (211 mg) in carbon tetrachloride (2.2 ml) at -78° C. The solution was allowed to warm to 0° C. during 45 minutes and concentrated. The residue was dissolved in ethyl acetate (30 ml) and washed with a chilled aqueous sodium bicarbonate (2.5 g), water, and brine. Drying over magnesium sulfate and evaporation left an oil (1.30 g), which showed two spots on silica gel thin layer chromatography (1:1 hexane/ethyl acetate). The residue was chromatographed on silica gel (40 g) eluting with 10-30% ethyl acetate in hexane to afford firstly a mixture (5:6:4) of methyl 2-[(3S)-4-chloro-3-{1-(p-nitrobenzyloxycarbonyloxy)ethyl}-2-oxoazetidin-1-yl]-3-methylbutenoate [a mixture (5:6:4) of (1S,4R) isomer, (1R, 4R) isomer and (1R, 4S) isomer] (550 mg).

Provenance & Evidence