CAS 124774-48-7 and 124774-49-8 is the registry number for (2RS,4S)-2-((((2R)-2-Amino-2-phenylacetyl)amino)methyl)-5,5-dimethylthiazolidine-4-carboxylic Acid (Penilloic Acids of Ampicillin). Offered by: Mikromol. Available pack sizes: 4x25mg, 25mg, 100mg.