Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 3,3-dimethyl-7-oxo-6-[[(2-propenylthio)acetyl]amino]-, (2S,5R,6R)- (9CI);4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,3,3-dimethyl-7-oxo-6-[[(2-propenylthio)acetyl]amino]-, [2S-(2a,5a,6b)]-; 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,6-[2-(allylthio)acetamido]-3,3-dimethyl-7-oxo- (7CI,8CI); Penicillin O (6CI);Allomercaptomethylpenicillin; Allylmercaptomethylpenicillin;Allylmercaptomethylpenicillinic acid; Allylthiomethylpenicillin; Almecillin;Cer-O-Cillin; Penicillin AT; Penicillin, [(2-propenylthio)methyl]-