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

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

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

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

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

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

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

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

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

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

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