Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 6,6-dibromo-3,3-dimethyl-7-oxo-, methyl ester (8CI);4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,6,6-dibromo-3,3-dimethyl-7-oxo-, methyl ester, (2S-cis)-; Methyl6,6-dibromopenicillanate