(6R,7S)-7-((2R,3S)-2-(4-ethyl-2,3-dioxopiperazine-1-carboxamido)-3-hydroxybutanamido)-7-methoxy-3-((4-methyl-5-thioxo-4,5-dihydro-1H-tetrazol-1-yl)methyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid