Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 3,3-dimethyl-7-oxo-6-[2-(phenylthio)acetamido]- (6CI,7CI,8CI);4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,3,3-dimethyl-7-oxo-6-[[(phenylthio)acetyl]amino]-, (2S,5R,6R)- (9CI);4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, 3,3-dimethyl-7-oxo-6-[[(phenylthio)acetyl]amino]-,[2S-(2a,5a,6b)]-; (Phenylthiomethyl)penicillin;3,3-Dimethyl-7-oxo-6-[2-(phenylthio)acetamido]-4-thia-1-azabicyclo-[3.2.0]heptane-2-carboxylicacid; Penicillin, [(phenylthio)methyl]-; Phenylmercaptomethylpenicillin;Thiphencillin; Tifencillin