Acetic acid (6R,7S)-7-methoxy-5,5,8-trioxo-2-(pyrrolidine-1-carbonyl)-5λ6-thia-1-aza-bicyclo[4.2.0]oct-2-en-3-ylmethyl ester

3-[[(6R,7S)-7-methoxy-5,5,8-trioxo-2-(pyrrolidine-1-carbonyl)-5λ⁶-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methylsulfanyl]-2-methyl-1H-1,2,4-triazine-5,6-dione