Purification of 5-pyrimidinecarboxamides

A process is provided for the purification to highly purified states of 5-pyrimidinecarboxamides which are essentially insoluble in both organic and inorganic solvents. The 5-pyrimidinecarboxamide to be purified is contacted with an organic base having a pKa value in excess of 6.95 to form an adduct. The adduct is purified through recrystallization and the desired 5-pyrimidinecarboxamide is regenerated from the adduct in highly purified form with acid. Additionally, an adduct resulting from the combination of a 5-pyrimidinecarboxamide with such an organic base is provided, which adduct is capable of being purified using recrystallization techniques, where the 5-pyrimidinecarboxamide is not itself capable of being so purified due to its relative insolubility in organic and inorganic solvents.