{4-[(2-Amino-acetyl)-cyclopropyl-amino]-cyclohexyl}-carbamic acid tert-butyl ester

(1R,4R)-[4-((S)-2-Amino-propionylamino)-cyclohexyl]-carbamic acid tert-butyl ester

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

4-{[((S)-2-Amino-propionyl)-methyl-amino]-methyl}-piperidine-1-carboxylic acid tert-butyl ester

(S)-2-{[((S)-2-Amino-propionyl)-ethyl-amino]-methyl}-pyrrolidine-1-carboxylic acid tert-butyl ester

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

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

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

{4-[((S)-2-Amino-propionyl)-isopropyl-amino]-cyclohexyl}-carbamic acid tert-butyl ester

3-[((S)-2-Amino-propionyl)-cyclopropyl-amino]-pyrrolidine-1-carboxylic acid tert-butyl ester

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