Butanethiol → (3S, 4R)-3-[(R)-1-t-Butyldimethylsilyloxyethyl]-4-[(butylthio)carbonylmethyl]-2-azetidinone

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Reaction Steps

542 mg (1.89 mmole) of (3S, 4R)-3-[(R)-1-t-butyldimethylsilyloxyethyl]-4-carboxymethyl-2-azetidinone, 212 mg (2.36 mmole) of butyl mercaptan, 381 mg (3.77 mmole) of triethylamine and 1.04 g (3.78 mmole) of diphenylphosphoryl azide were dissolved in 10 ml of N,N-dimethylformamide and the solution was allowed to stand overnight at room temperature. After dilution with ethyl acetate, the mixture was washed with water several times and then dried. The solvent was distilled off and the residue (1.25 g) was purified by column chromatography through 23 g of silical gel, eluted with mixtures of hexane and ethyl acetate in volume ratios ranging from 4:1 to 2:1, to give 649 mg (yield 96%) of the title product. Recrystallization from hexane gave colourless needles, melting at 56.5°-57° C.

Provenance & Evidence