[4-((S)-2-Amino-propionylamino)-cyclohexyl]-cyclopropyl-carbamic acid benzyl ester

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

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

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

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

(1R,4R)-[4-((S)-2-Amino-3-methyl-butyrylamino)-cyclohexyl]-isopropyl-carbamic acid benzyl ester

[1-((S)-2-Amino-3-methyl-butyryl)-piperidin-3-ylmethyl]-cyclopropyl-carbamic acid benzyl ester

((S)-3-Benzyloxycarbonylamino-piperidin-1-yl)-acetic acid

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

[(S)-3-(Benzyloxycarbonyl-ethyl-amino)-pyrrolidin-1-yl]-acetic acid

{2-[(Benzyloxycarbonyl-isopropyl-amino)-methyl]-pyrrolidin-1-yl}-acetic acid