methyl 2-[[2-(phenylmethoxycarbonylamino)acetyl]amino]propanoate

(2S)-2-methyl-1-[2-(phenylmethoxycarbonylamino)acetyl]pyrrolidine-2-carboxylic acid

methyl 3-phenyl-2-[[2-(phenylmethoxycarbonylamino)acetyl]amino]propanoate

dibenzyl (2S,5'R)-2-[1'-(2''-benzyloxycarbonylamino-acetyl)-6'-oxo-1',7'-diazaspiro[4.4]non-7'-yl]-pentanedioate

methyl N-benzyloxycarbonyl-glycyl-L-2-ethylprolinate