Carbon Disulfide → (3S, 4R)-3-[(R)-1-t-Butyldimethylsilyloxyethyl]-4-[(R)-1-methyl-2-(p-nitrobenzyloxycarbonylamino)ethylthio(thiocarbonyl)]thioazetidin-2-one

Participants

Reaction Conditions

Reaction Steps

To a solution of sodium (518 mg, 22.5 mmole) in methanol (100 ml) was added at -10° C. (R)-1-methyl-2-(p-nitrobenzyloxycarbonylamino)ethanethiol (6.61 g, 23.1 mmole). The mixture was stirred for 5 minutes, and then carbon disulphide (1.76 g, 23.1 mmole) was added and stirring was continued for a further 10 minutes. (3R, 4R)-4-acetoxy-3-[(R)-1-t-butyldimethylsilyloxyethyl]azetidin-2-one (6.46 g, 22.5 mmole) was then added at the same temperature, after which the bath temperature was raised to 0° C. over about 1 hour. About 300 mg of acetic acid was then added, and the reaction mixture was diluted with ethyl acetate and washed with a saturated aqueous solution of sodium chloride. After the solution had been dried, the solvent was distilled off under reduced pressure and the residue was purified through column chromatography (200 g of silica gel), eluted with a 10% v/v solution of ethyl acetate in benzene, affording the desired compound (10.8 g, 84%) in the form of a yellow oil.

Provenance & Evidence