(4S)-2-[carboxy[(2-phenoxyacetyl)amino]-methyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid; (4S)-2-(carboxy(2-phenoxyacetamido)methyl)-5,5-dimethylthiazolidine-4-carboxylic acid; Penicilloic V Acid