acetoxymethyl(5R,6S)-2-carbamoyloxymethyl-6-[1(R)-trichloroethoxycarbonyloxyethyl]-penem-3-carboxylate

acetoxymethyl (5R,6S)-6-bromo-3-((carbamoyloxy)methyl)-6-((R)-1-hydroxyethyl)-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

(5R,6S)-6-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-3-carbamoyloxymethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid acetoxymethyl ester

acetoxymethyl 2-((2R,3S)-2-((S)-(3-hydroxyprop-1-en-2-yl)sulfinyl)-4-oxo-3-((R)-1-(((2,2,2-trichloroethoxy)carbonyl)oxy)ethyl)azetidin-1-yl)-3-methylbut-2-enoate

(5R,6S)-acetoxymethyl 3-((carbamoyloxy)methyl)-7-oxo-6-((R)-1-((trimethylsilyl)oxy)ethyl)-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate