20880-67-5 4-Hydroxypenicillin V 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 6-(((4-hydroxyphenoxy)acetyl)amino)-3,3-dimethyl-7-oxo-, (2S-(2alpha,5alpha,6beta))- p-Hydroxypenicillin V