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

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

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

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

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

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

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

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

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

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

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