(6R-trans)-3-[(carbamoyloxy)methyl]-8-oxo-7-(2-thienylacetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,6β)-3-[[(Aminocarbonyl)oxy]methyl]-8-oxo-7α-[(2-thienylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid