N-{2-[2-(1-Ethoxycarbonyl-2-phenyl-ethylcarbamoyl)-phenylcarbamoyl]-phenyl}-succinamic acid ethyl ester

2-(2-{2-[(1H-Indole-2-carbonyl)-amino]-benzoylamino}-benzoylamino)-3-phenyl-propionic acid ethyl ester

2-{2-[2-(3-1H-Indol-3-yl-propionylamino)-benzoylamino]-benzoylamino}-3-phenyl-propionic acid ethyl ester

2(RS)-{2-[(o-nitrocinnamoyl)-amino]-benzoylamino}-3-phenyl-propionic acid ethyl ester

2-[2-(2-Benzoylamino-benzoylamino)-benzoylamino]-3-phenyl-propionic acid ethyl ester