Sodium; (6R,7R)-3-(acetyloxymethyl)-8-oxo-7-[(2-pyridin-4-ylsulfanylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate
Sodium (6R-trans)-3-(Acetoxymethyl)-8-oxo-7-((4-pyridylthio)acetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylate