The Collaborative International Dictionary of English v.0.48:

Violuric \Vi`o*lu"ric\, a. [Violet + barbituric.] (Chem.)
   Of, pertaining to, or designating, a complex nitroso
   derivative of barbituric acid. It is obtained as a white or
   yellow crystalline substance, and forms characteristic
   yellow, blue, and violet salts.
   [1913 Webster]