9-chloro-4,5,6,10b-tetrahydro-1-(α-methyl-β-ethoxycarbonylethenyl)amino-6-methyl-10b-phenylazetidino<1,2-d><1,4>benzodiazepine-2,5-dione
7-(1'-carbethoxy-1'-propen-2'-ylamino)-6-phenylcepham
(E)-3-[(2S,3R)-2-(3,4-Dimethoxy-phenyl)-1-ethoxycarbonylmethyl-4-oxo-azetidin-3-ylamino]-but-2-enoic acid ethyl ester
(E)-3-((3R,4S)-1-Ethoxycarbonylmethyl-2-oxo-4-phenyl-azetidin-3-ylamino)-but-2-enoic acid ethyl ester
(E)-3-((1S,9bS)-2-Oxo-9b-p-tolyl-1,4,5,9b-tetrahydro-2H-azeto[2,1-a]isoquinolin-1-ylamino)-but-2-enoic acid ethyl ester