H951210 3-Hydroxy-2-(7-oxo-3-phenyl-4-oxa-2,6-diazabicyclo[3.2.0]hept-2-en-6-yl)but-3-enoic Acid Benzhydryl Ester

B207960 (6R-trans)-7-(Benzoylamino)-3-methyl-8-oxo-5-oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic Acid Diphenylmethyl Ester

C366755 α-[2-Chloro-1-hydroxy-1-(hydroxymethyl)ethyl]-7-oxo-3-phenyl-4-oxa-2,6-diazabicyclo[3.2.0]hept-2-ene-6-acetic Acid Diphenylmethyl Ester

B207985 (6R,7R)-7-Benzamido-3-methylene-8-oxo-5-thia-1-azabicyclo[4.2.0]octane-2-carboxylic Acid 5-Oxide Benzhydryl Ester