(6R)-7t-amino-2-isopropylidene-(6rH)-5-thia-1-aza-bicyclo[4.2.0]octane-3,8-dione

N-((6R)-2-isopropylidene-3,8-dioxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-7t-yl)-phthalimide

(2S,5R,6S)-6-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid