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

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

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

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

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

(1R,4R)-[4-(tert-Butoxycarbonyl-methyl-amino)-cyclohexylamino]-acetic acid

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

[2-(tert-Butoxycarbonyl-ethyl-amino)-cyclohexylamino]-acetic acid

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

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

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