5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 7-[[(2Z)-[5-chloro-2-[[(1,1-dimethylethoxy)carbonyl]amino]-4-thiazolyl][[2- (1,1-dimethylethoxy)-2-oxoethoxy]imino]acetyl]amino]-3-(chloromethy