Synonyms: 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 3,3-dimethyl-6-(2-methyl-2-phenoxypropionamido)-7-oxo- (6CI,7CI,8CI);4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,3,3-dimethyl-6-[(2-methyl-1-oxo-2-phenoxypropyl)amino]-7-oxo-, [2S-(2a,5a,6b)]-; 3,3-Dimethyl-6-(2-methyl-2-phenoxypropionamido)-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid; Isopropicillin; Lilly 33332; Penicillin, (1-methyl-1-phenoxyethyl)-; a-Phenoxyisopropylpenicillin