methyl 6β-phthalimidopenicillanate 1,1-dioxide

(2S,5S,6S)-6-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid methyl ester

methyl (2S)-2-[(3R,4S)-4-chloro-3-phthalimido-2-oxazetidin-1-yl]-2-(1-chlorothio-1-methylethyl)-acetate

(S)-2,2-dimethyl-7-oxo-6-phthalimido-2,3,4,7-tetrahydro-[1,4]thiazepine-3-carboxylic acid