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

[2-((S)-2-Amino-3-methyl-butyrylamino)-cyclohexyl]-cyclopropyl-carbamic acid tert-butyl ester

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

[4-(tert-Butoxycarbonyl-methyl-amino)-cyclohexylamino]-acetic acid

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

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

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

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

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

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

[1-(2-Hydroxy-ethyl)-piperidin-4-yl]-methyl-carbamic acid benzyl ester