4-[[(2R)-2,4-二羟基-3,3-二甲基-1-氧代丁基]氨基]-丁酸

4-[[2-(2,6-dimethylanilino)-2-oxoethyl]amino]butanoic acid

4-[(2-chloro-5H-pyrrolo[3,2-d]pyrimidin-4-yl)amino]butanoic acid

4-{[(4-Methylphenyl)sulfonyl]amino}butanoic acid

4-(4-hydroxybutanoylamino)butanoic acid