(S)-3-((S)-2-Amino-propionylamino)-piperidine-1-carboxylic acid benzyl ester

4-[((S)-2-Amino-propionyl)-ethyl-amino]-piperidine-1-carboxylic acid benzyl ester

3-[((S)-2-Amino-propionyl)-isopropyl-amino]-piperidine-1-carboxylic acid benzyl ester

(1R,4R)-{4-[((S)-2-Amino-propionyl)-isopropyl-amino]-cyclohexyl}-carbamic acid benzyl ester

2-{[((S)-2-Amino-propionyl)-cyclopropyl-amino]-methyl}-piperidine-1-carboxylic acid benzyl ester

(R)-3-((S)-2-Amino-3-methyl-butyrylamino)-piperidine-1-carboxylic acid benzyl ester

2-{[((S)-2-Amino-3-methyl-butyryl)-methyl-amino]-methyl}-pyrrolidine-1-carboxylic acid benzyl ester

{4-[((S)-2-Amino-3-methyl-butyryl)-methyl-amino]-cyclohexyl}-carbamic acid benzyl ester

(R)-3-[((S)-2-Amino-3-methyl-butyryl)-ethyl-amino]-piperidine-1-carboxylic acid benzyl ester

[(1-Benzyl-pyrrolidin-2-ylmethyl)-amino]-acetic acid

[(1-Benzyl-pyrrolidin-3-yl)-methyl-amino]-acetic acid