The molecule is a thiazolidinemonocarboxylate anion resulting from proton loss from the carboxy group located on the beta-lactam ring of amoxicilloic acid. It is a conjugate base of an amoxicilloic acid.
(2R,4S)-2-[(R)-[[(2R)-2-amino-2-(4-hydroxyphenyl)acetyl]amino]-carboxymethyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylate