(4R,5S,6S)-3-((6S,7aS)-3-Cyclopropyl-3-methyl-1-oxo-hexahydro-pyrrolo[1,2-c]imidazol-6-ylsulfanyl)-6-((R)-1-hydroxy-ethyl)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid

(4R,5S,6S)-6-((R)-1-Hydroxy-ethyl)-3-((3S,6S,7aS)-3-hydroxymethyl-3-methyl-1-oxo-hexahydro-pyrrolo[1,2-c]imidazol-6-ylsulfanyl)-4-methyl-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid

(4R,5S,6S)-6-((R)-1-Hydroxy-ethyl)-4-methyl-3-((6S,7aS)-3-methyl-1-oxo-3-phenyl-hexahydro-pyrrolo[1,2-c]imidazol-6-ylsulfanyl)-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid

(5S,7S)-2,2,3-trimethyl-7-mercapto-4-oxo-1,3-diazabicyclo<3.3.0>octane

Thioacetic acid S-((6S,7aS)-3,3-dimethyl-1-oxo-hexahydro-pyrrolo[1,2-c]imidazol-6-yl) ester