| 摘要 |
Improved processes for preparation of racemic, cis- and optically active (3S,4R)-3[1(R)-t-butyl-dimethylsilyloxy)-ethyl]-4-[1-oxo-3-thiolanylth io(thiocarbonyl)thio]azetidin-2-ones, process improvements for certain intermediates therefor and a novel intermediate for said racemic, cis- and trans-compounds, which compounds are useful as intermediates for antibacterial 5R,6S-6-[1(R)-hydroxyethyl]-2-(1-oxo-3-thiolanylthio)-2-penem-3-carbox ylic acids and the pharmaceutically-acceptable salts and the pivaloyloxymethyl esters thereof.
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