(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl (2S,5R,6R)-6-[[(2R)-2-amino-2-phenylacetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate

(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl (2S,5R,6R)-6-[[(2R)-2-azanyl-2-phenyl-ethanoyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate

(2S,5β,6R)-6α-[[(R)-Amino(phenyl)acetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2β-carboxylic acid (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl ester

(2S,5R,6R)-6-[[(2R)-2-amino-2-phenyl-acetyl]amino]-7-keto-3,3-dimethyl-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (2-keto-5-methyl-1,3-dioxol-4-yl)methyl ester