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

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

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

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

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

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

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

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

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

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

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