(R)-3-((S)-2-Amino-propionylamino)-pyrrolidine-1-carboxylic acid tert-butyl ester

4-((S)-2-Amino-propionylamino)-piperidine-1-carboxylic acid tert-butylester

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

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

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

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

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

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

4-((S)-2-Amino-3-methyl-butyrylamino)-piperidine-1-carboxylic acid tert-butyl ester

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

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