(2S-trans)-N-<2-(acetyloxy)-4-oxo-3-azetidinyl>benzeneacetamide

2-((1R,5R)-3-Benzyl-7-oxo-4-thia-2,6-diaza-bicyclo[3.2.0]hept-2-en-6-yl)-3-methyl-but-2-enoic acid benzyl ester

Acetic acid 1-((1R,5R)-3-benzyl-7-oxo-4-thia-2,6-diaza-bicyclo[3.2.0]hept-2-en-6-yl)-2-methyl-allyl ester

(3S,4S)-3-N-(Benzyloxycarbonyl)-3-N-(phenylacetoxy)amino-4-acetoxyazetidin-2-one

(R)-2-((1R)-3-benzyl-7-oxo-(1rH,5cH)-4-thia-2,6-diaza-bicyclo[3.2.0]hept-2-en-6-yl)-3-methyl-but-3-enoic acid methyl ester