"(1R,5S)-tert-butyl 7-oxo-6-((S)-1-phenylethyl)-2,6-diaza-bicyclo[3.2.0]heptane-2-carboxylate"
"(1R,5S)-tert-butyl 7-oxo-6-((S)-1-phenylethyl)-2,6-diaza-bicyclo[3.2.0]heptane-2-carboxylate"
"(1R,5S)-tert-butyl 7-oxo-6-((S)-1-phenylethyl)-2,6-diaza-bicyclo[3.2.0]heptane-2-carboxylate"