{(2S,3S)-3-[1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-methoxy-thioacetic acid S-m-tolyl ester
3(S)-<1(R)-<(tert-butyldimethylsilyl)oxy>ethyl>-4(R)-<<(phenylthio)carbonyl>methyl>azetidin-2-one
(S)-3-(2-{(2R,3S)-3-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-acetylsulfanyl)-pyrrolidine-1-carboxylic acid 4-nitro-benzyl ester
(3S,4R)-3-<(R)-1-(p-nitrobenzyloxycarbonyloxy)ethyl>-4-<(phenylthiocarbonyl)methyl>-2-azetidinone
N-<<(p-nitrobenzyl)oxy>carbonyl>-O-<<(p-nitrobenzyl)oxy>carbonyl>thienamycin p-nitrobenzyl ester