4-27-00-05890 (Beilstein Handbook Reference) 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 3,3-dimethyl-6-(2-(p-hydroxyphenyl)acetamido)-7-oxo- 525-91-7 BRN 0049686 Penicillin III Penicillin X p-Hydroxybenzylpenicillin