(2S,5R,6R)-6-bromo-3,3-dimethyl-7-oxo-4-thia1-azabicyclo[3.2.0]heptane-2-carboxylic acid; [2S-(2α,5α,6β)]-6-Bromo-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic Acid; 6β-Bromopenicillanic Acid