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

3-[((S)-2-Amino-3-methyl-butyryl)-isopropyl-amino]-piperidine-1-carboxylic acid tert-butyl ester

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

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

3-(Carboxymethyl-amino)-piperidine-1-carboxylic acid benzyl ester

4-[(Carboxymethyl-amino)-methyl]-piperidine-1-carboxylic acid benzyl ester

(2-Benzyloxycarbonylamino-cyclohexylamino)-acetic acid

2-[(Carboxymethyl-ethyl-amino)-methyl]-piperidine-1-carboxylic acid benzyl ester

2-[(Carboxymethyl-isopropyl-amino)-methyl]-pyrrolidine-1-carboxylic acid benzyl ester

(S)-3-(Carboxymethyl-isopropyl-amino)-piperidine-1-carboxylic acid benzyl ester

(1R,4R)-[(4-Benzyloxycarbonylamino-cyclohexyl)-isopropyl-amino]-acetic acid