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(1988)3-Methyl-2-[(3R,4R)-2-oxo-3-(2-oxo-propyl)-4-phenylacetylsulfanyl-azetidin-1-yl]-but-2-enoic acid 2,2-dimethyl-propionyloxymethyl ester
2,2-Dimethyl-propionic acid 2-oxo-2-[(3R,4R)-2-oxo-3-(2-oxo-heptyl)-4-(2-phenoxy-acetylsulfanyl)-azetidin-1-yl]-acetoxymethyl ester
2,2-Dimethyl-propionic acid 2-oxo-2-[(3R,4R)-2-oxo-3-(2-oxo-4-phenyl-butyl)-4-(2-phenoxy-acetylsulfanyl)-azetidin-1-yl]-acetoxymethyl ester
2,2-Dimethyl-propionic acid 2-[(2R,3R)-2-[2-(4-bromo-2-chloro-6-methyl-phenoxy)-acetylsulfanyl]-4-oxo-3-(2-oxo-propyl)-azetidin-1-yl]-2-oxo-acetoxymethyl ester
2-[(2R,3R)-2-[2-(4-Bromo-2-chloro-6-methyl-phenoxy)-acetylsulfanyl]-4-oxo-3-(2-oxo-propyl)-azetidin-1-yl]-3-methyl-but-2-enoic acid 2,2-dimethyl-propionyloxymethyl ester