4-(8-(benzyloxycarbonyl)-4-oxo-1-phenyl-1,3,8-triazaspiro[4.5]decan-3-yl)benzoic acid

benzyl 3-(3-(methylsulfonamido)benzyl)-4-oxo-1-phenyl-1,3,8-triazaspiro[4.5]decane-8-carboxylate

benzyl 3-(3-aminobenzyl)-4-oxo-1-phenyl-1,3,8-triazaspiro[4.5]decane-8-carboxylate