N-(4-Amino-3-pyridinyl)-acetamide-d3 Hydrochloride is the deuterium labeled impurity of the drug 3,4-Diaminopyridine (D415950), which is used as a reagent in the preparation of 9-deazaxanthine derivatives which has activity as dual A2A antagonists/MAO-B inhibitors with potential as anti-Parkinson's agents.