1'-ethoxycarbonyloxyethyl-(6-D-alpha-aminophenylacetamido)penicillanate
1-[(ethoxycarbonyl)oxy]ethyl (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