2-[(2R)-2r-benzothiazol-2-yldisulfanyl-4-oxo-3c-(2-phenyl-acetylamino)-azetidin-1-yl]-3-methyl-but-2-enoic acid 2,2,2-trichloro-ethyl ester

2,2,2-trichloroethyl (1S,3S,5R,6R,2'R)-6-(2'-phenyl-2'-<2,2,2-trichloroethoxycarbonylamino>acetamido)-2,2-dimethylpenam-3-carboxylate

2,2,2-trichloroethyl 6-diazopenicillanate (1S)-S-oxide

2,2,2-trichloroethyl (1S,3S,5R,6R,2'R)-6-(2'-azido-2'-phenylacetamido)-2,2-dimethylpenam-3-carboxylate

2,2,2-trichloroethyl (2S,4S,5R,6R)-3,3-dimethyl-6-(N-nitroso-2-phenylacetamido)-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate 4-oxide