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

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

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

[2-(tert-Butoxycarbonylamino-methyl)-pyrrolidin-1-yl]-acetic acid

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

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

[(S)-3-(tert-Butoxycarbonyl-isopropyl-amino)-pyrrolidin-1-yl]-acetic acid

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

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

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

[(R)-1-(2-Hydroxy-ethyl)-piperidin-3-yl]-carbamic acid benzyl ester