cynurine

from The Century Dictionary.

• noun A colorless bitter compound, HOC₉H₆N, prepared by the fusion of cynurenic acid and also by the oxidation of cinchonine and certain related compounds. It crystallizes in lustrous, monoclinic, anhydrous prisms or, with 3H₂O, in needles melting at 201° C. and 52° C. respectively. Also called 4-hydroxyquinoline.