MUREBIDE (NH4.C8H4N506,

See also:

• H2O (combined)

H2O)  , the ammonium salt of purpuric acid . It may be prepared by heating alloxantin in ammonia gas to Too° C., or by boiling uramil with mercuric oxide (J. v . Liebig, F . Wohler, Ann., 1838, 26, 319), 2C4H5N303+0= NH4•C5H4N506+H20 . W . N . Hartley (Jour . Chem . Soc., 1905, 87, 1791) found considerable difficulty in obtaining specimens of murexide sufficiently pure to give concordant results when examined by means of their absorption spectra, and consequently devised a new method of preparation for murexide . In this process alloxantin is dissolved in a large excess of boiling absolute alcohol, and dry ammonia gas is passed into the solution for about three hours . The solution is then filtered from the precipitated murexide, which is washed with absolute alcohol and dried . The salt obtained in this way is in the anhydrous state .

It may also be prepared by digesting alloxan with alcoholic ammonia at about 78° C.; the

purple solid so formed is easily soluble in water, and the solution produced is indistinguishable from one of murexide . On the constitution of murexide see also 0 . Piloty (Ann., 1904, 333, 30) ; R . Mohlau (Ber., 1904, 37, 2686) ; and M . Slimmer and J . Stieglitz (Amer . Chem . Jour., 1904, 31, 661) .