1-allyl-1,2-dihydro-2-(2,2,2-trichloroethoxycarbonyl)-β-carboline

(S)-9-{N-(biphenyl-4-sulfonyl)prolinyl}-β-carboline

(S)-9-{--(p-neopentylphenylsulfonyl)prolinyl}-β-carboline

1-Allyl-9-((S)-1-naphthalen-2-ylmethyl-5-oxo-pyrrolidine-2-carbonyl)-1,9-dihydro-β-carboline-2-carboxylic acid 2,2,2-trichloro-ethyl ester

9-[N-(anthracen-9-ylmethyl)-(S)-pyroglutamyl]-β-carboline

9-[N-(naphthalen-2-ylmethyl)-(S)-pyroglutamyl]-β-carboline

9-[N-(p-nitrobenzoyl)-(S)-pyroglutamyl]-β-carboline

9-[N-[p-(tert-Amyl)phenylsulfonyl]-L-prolinyl]-β-carboline

9-[N-(benzoyl)-(S)-pyroglutamyl]-β-carboline

(S)-9-{N-(p-isopropylphenylsulfonyl)prolinyl}-β-carboline