The Collaborative International Dictionary of English v.0.48:

Alloxan \Al*lox"an\, n. [Allantoin + oxalic, as containing the
   elements of allantion and oxalic acid.] (Chem.)
   An oxidation product of uric acid. It is of a pale reddish
   color, readily soluble in water or alcohol.
   [1913 Webster]