(R)-3-((S)-2-Amino-3-methyl-butyrylamino)-piperidine-1-carboxylic acid tert-butyl ester

3-[((S)-2-Amino-3-methyl-butyryl)-methyl-amino]-pyrrolidine-1-carboxylic acid tert-butyl ester

3-[((S)-2-Amino-3-methyl-butyryl)-ethyl-amino]-piperidine-1-carboxylic acid tert-butyl ester

(R)-3-[((S)-2-Amino-3-methyl-butyryl)-isopropyl-amino]-pyrrolidine-1-carboxylic acid tert-butyl ester

{4-[((S)-2-Amino-3-methyl-butyryl)-isopropyl-amino]-cyclohexyl}-carbamic acid tert-butyl ester

(R)-3-(Carboxymethyl-amino)-pyrrolidine-1-carboxylic acid benzyl ester

3-[(Carboxymethyl-amino)-methyl]-piperidine-1-carboxylic acid benzyl ester

(1R,4R)-(4-Benzyloxycarbonylamino-cyclohexylamino)-acetic acid

3-[(Carboxymethyl-ethyl-amino)-methyl]-piperidine-1-carboxylic acid benzyl ester

(S)-3-(Carboxymethyl-isopropyl-amino)-piperidine-1-carboxylic acid benzyl ester

(R)-3-(Carboxymethyl-cyclopropyl-amino)-piperidine-1-carboxylic acid benzyl ester