4-nitrobenzyl 2-diazo-3-oxo-butanoate
(2S,5R,6R)-benzyl 6-(1,3-dioxoisoindolin-2-yl)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate
secopenicillin
{(2R,3R)-3-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-2-[(2-methyl-[1,3]dioxolan-2-yl)-(4-nitro-benzyloxycarbonyl)-methylsulfanyl]-4-oxo-azetidin-1-yl}-(triphenyl-λ5-phosphanylidene)-acetic acid 4-nitro-benzyl ester
(Z)-2-{(2R,3R)-3-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-1-[(4-nitro-benzyloxycarbonyl)-(triphenyl-λ5-phosphanylidene)-methyl]-4-oxo-azetidin-2-ylsulfanyl}-3-hydroxy-but-2-enoic acid 4-nitro-benzyl ester
[(2R,3R)-3-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-2-(4-nitro-benzyloxyoxalylsulfanyl)-4-oxo-azetidin-1-yl]-(triphenyl-λ5-phosphanylidene)-acetic acid 4-nitro-benzyl ester
Chloro-{(2R,3R)-3-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-2-[(2-methyl-[1,3]dioxolan-2-yl)-(4-nitro-benzyloxycarbonyl)-methylsulfanyl]-4-oxo-azetidin-1-yl}-acetic acid 4-nitro-benzyl ester
{(2R,3R)-3-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-2-[(2-methyl-[1,3]dioxolan-2-yl)-(4-nitro-benzyloxycarbonyl)-methylsulfanyl]-4-oxo-azetidin-1-yl}-hydroxy-acetic acid 4-nitro-benzyl ester