3-((E)-2-Methoxyamino-vinyl)-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester

4-nitrobenzyl (E)-3-(((methoxyimino)methoxy)methyl)-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

(2-Oxo-4-tritylsulfanyl-azetidin-1-yl)-(triphenyl-λ5-phosphanylidene)-acetic acid 4-nitro-benzyl ester