20520-33-6 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 3,3-dimethyl-6-((2,2-dimethyl-1-oxopropyl)amino)-7-oxo-, monosodium salt 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 3,3-dimethyl-7-oxo-6-pivalamido-, Na tert-Butylpenicillin sodium salt