(R)-2-[(2R,3R)-2-(Benzothiazol-2-yldisulfanyl)-3-carbamoylmethyl-4-oxo-azetidin-1-yl]-3-methyl-but-3-enoic acid benzyl ester

(2S,5R)-6-[1-Carbamoyl-meth-(E)-ylidene]-3,3-dimethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester