(5-Amino-6-(methoxy-d3)pyrazin-2-yl)boronic Acid is the labeled analogue of (5-Amino-6-methoxypyrazin-2-yl)boronic Acid (A611895). (5-Amino-6-methoxypyrazin-2-yl)boronic Acid has been used as a reactant for the preparation of aminoquinazolinone compounds to be used for the treatment of cell proliferative diseases.