(6S,7S,8R,9S)-7-butyl-8,9-epoxy-1-azaspiro[5.5]undecan-2-one

(2S,1'S)-2-(1'-butylbut-2'-enyl)-6-oxopiperidine-2-carboxylic acid 1-methyl ester

(6S,7S)-7-butyl-1-azaspiro[5.5]undec-8-en-2-one

(6S,7S)-7-butyl-11-hydroxy-1-azaspiro[5.5]undec-8-en-2-one

Imidazole-1-carbothioic acid O-((6S,11R)-11-butyl-2-oxo-1-aza-spiro[5.5]undec-9-en-7-yl) ester