N-((3R)-2c-benzothiazol-2-yldisulfanyl-4-oxo-azetidin-3r-yl)-phthalimide

((2R)-2r-benzothiazol-2-yldisulfanyl-4-oxo-3c-phthalimido-azetidin-1-yl)-oxo-acetic acid methyl ester

(6R)-3-acetoxymethyl-5ξ,8-dioxo-7t-phthalimido-(6rH)-5λ4-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid methyl ester