xanthinine

from The Century Dictionary.

• noun A colorless, pulverulent compound, C₄H₃O₂N₃, prepared by heating ammonium thionurate.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A complex nitrogenous substance related to urea and uric acid, produced as a white powder; -- so called because it forms yellow salts, and because its solution forms a blue fluorescence like quinine.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete, organic chemistry A poorly-characterised material, related to urea and uric acid, that forms yellow salts, and exhibits a blue fluorescence