2-[[[(1,1-Dimethylethoxy)carbonyl]amino]methyl]-propanoic-3,3,3-d3 Acid Phenylmethyl Ester is an intermediate in the synthesis of labelled 3-Aminoisobutyric Acid (A611587). Unlabelled 3-Aminoisobutyric Acid (A611585) is a substituted β-alanines and is used for preparation and isolation of D(-)-β-Aminoisobutyric Acid.