(6R)-3-[(Acetyloxy)methyl]-7α-[(R)-formyloxyphenylacetylamino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt

sodium [6R-[6alpha,7beta(R*)]]-3-(acetoxymethyl)-7-[(formyloxy)phenylacetamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate