(1R,4R)-[4-((S)-2-Amino-3-methyl-butyrylamino)-cyclohexyl]-methyl-carbamic acid tert-butyl ester

[1-((S)-2-Amino-3-methyl-butyryl)-piperidin-4-yl]-ethyl-carbamic acid tert-butyl ester

[1-((S)-2-Amino-3-methyl-butyryl)-pyrrolidin-3-yl]-isopropyl-carbamic acid tert-butyl ester

[1-((S)-2-Amino-3-methyl-butyryl)-piperidin-3-ylmethyl]-isopropyl-carbamic acid tert-butyl ester

[(S)-1-((S)-2-Amino-3-methyl-butyryl)-pyrrolidin-3-yl]-cyclopropyl-carbamic acid tert-butyl ester

((R)-3-tert-Butoxycarbonylamino-pyrrolidin-1-yl)-acetic acid

{3-[(tert-Butoxycarbonyl-methyl-amino)-methyl]-pyrrolidin-1-yl}-acetic acid

[4-(tert-Butoxycarbonyl-methyl-amino)-piperidin-1-yl]-acetic acid

[3-(tert-Butoxycarbonyl-ethyl-amino)-piperidin-1-yl]-acetic acid

{(S)-2-[(tert-Butoxycarbonyl-isopropyl-amino)-methyl]-pyrrolidin-1-yl}-acetic acid

[(R)-3-(tert-Butoxycarbonyl-isopropyl-amino)-piperidin-1-yl]-acetic acid