Imp. A (EP): (2S,5R,6R)-6-Amino-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]-heptane-2-carboxylic Acid (6-AminopenicillanicAcid)

Imp. B (EP): (2S,5R,6R)-6-[[(2S)-2-Amino-2-phenylacetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic Acid (L-Ampicillin)

Imp. C (EP): (4S)-2-(3,6-Dioxo-5-phenylpiperazin-2-yl)-5,5-dimethylthiazolidine-4-carboxylic Acid (Diketopiperazines ofAmpicillin)

Imp. D (EP) as Sodium Salt: (4S)-2-[[[(2R)-2-Amino-2-phenylacetyl]amino]-carboxymethyl]-5,5-dimethylthiazolidine-4-carboxylic Acid Sodium Salt(Penicilloic Acids of Ampicillin Sodium Salt)

Imp. F (EP): (2RS,4S)-2-[[[(2R)-2-Amino-2-phenylacetyl]amino]methyl]-5,5-dimethyl-thiazolidine-4-carboxylic Acid (Penilloic Acids of Ampicillin)

Imp. K (EP): (2R)-2-[(2,2-Dimethylpropanoyl)amino]-2-phenylaceticAcid

Imp. H (EP): 3-Phenylpyrazin-2-ol

Imp. L (EP): (2R)-2-Amino-2-phenylacetic Acid (D-Phenylglycine)