Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 6-[2-[[[(carboxymethyl)thio]methyl]thio]acetamido]-3,3-dimethyl-7-oxo-(8CI); 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,6-[[[[[(carboxymethyl)thio]methyl]thio]acetyl]amino]-3,3-dimethyl-7-oxo-,[2S-(2a,5a,6b)]-; Penicillin, [[[[(carboxymethyl)thio]methyl]thio]methyl]-