Murexan

Mu`rex´an


n.1.(Chem.) A complex nitrogenous substance obtained from murexide, alloxantin, and other ureids, as a white, or yellowish, crystalline which turns red on exposure to the air; - called also uramil, dialuramide, and formerly purpuric acid.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.