(R)-2-{(2S,3S)-3-[1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-thiopropionic acid S-phenyl ester
Acetic acid (2R,3R)-3-[1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-1-trimethylsilanyl-azetidin-2-yl ester
(R)-2-{(2S,3S)-3-[1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-propionic acid
(S)-2-{(2S,3S)-3-[1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-thiopropionic acid S-phenyl ester
(S)-2-{(2S,3S)-3-[1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-propionic acid
1-β-methyl RS-533
(4R,5S,6S)-6-(1-Hydroxy-ethyl)-4-methyl-3-[(S)-1-(4-nitro-benzyloxycarbonyl)-pyrrolidin-3-ylsulfanyl]-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester
1-α-methyl RS-533
(4S,5S,6S)-6-(1-Hydroxy-ethyl)-4-methyl-3-((S)-1-{1-[(E)-4-nitro-benzyloxycarbonylimino]-ethyl}-pyrrolidin-3-ylsulfanyl)-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester
(4S,5S,6S)-6-(1-Hydroxy-ethyl)-4-methyl-3-[2-(4-nitro-benzyloxycarbonylamino)-ethylsulfanyl]-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester