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(2007/10/03)(R)-3-Chloro-7,8-dioxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
(6R,7R)-7-Amino-3-chloro-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
(6R,7R)-benzhydryl 8-oxo-7-(2-phenylacetamido)-3-(((trifluoromethyl)sulfonyl)oxy)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate
(6R,7R)-benzhydryl 3-chloro-8-oxo-7-(2-phenylacetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate
(6R,7R)-benzhydryl 3-hydroxy-8-oxo-7-(2-phenylacetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate