(1R,4R)-[4-((S)-2-Amino-propionylamino)-cyclohexyl]-ethyl-carbamic acid benzyl ester

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

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

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

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

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

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

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

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

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

[4-(Benzyloxycarbonyl-methyl-amino)-cyclohexylamino]-acetic acid