5-ethyl-1-[2-(1H-indol-3-yl)ethyl]-4-hydroxy-6-oxo-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid ethyl ester

(S)-3-ethyl-4-[(1-phenylethyl)amino]-1-[2-(1H-indol-3-yl)ethyl]-5,6-dihydro-2(1H)-pyridinone

2-({[3-(ethoxycarbonyl)propyl][2-(1H-indol-3-yl)ethyl]amino}carbonyl)butanoic acid ethyl ester

(R)-3-ethyl-1-[2-(1H-indol-3-yl)ethyl]-2,4-dioxo-3-piperidinepropanoic acid methyl ester

dimethyl (2S,3R)-3-ethyl-1-(9-phenylfluoren-9-yl)hexahydroquinolinate