6-Azabicyclo[3.2.0]hept-3-en-7-one, (1S)-

(1R,4S,5S,7S)-5-Hydroxy-9-methyl-3,9-diaza-tricyclo[5.2.1.04,8]decan-2-one

(1aS,1bR,3S,4aR,5aR)-2-Methyl-octahydro-1-oxa-2-aza-cyclopropa[a]pentalene-3-carboxylic acid amide

Toluene-4-sulfonic acid (1R,2S)-2-(benzyloxycarbonyl-cyanomethyl-amino)-cyclopent-3-enylmethyl ester