A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 213
by acting ou it with water it is oonverted iuto hydrazuhnarin or
azulmic add C4H6N6O ;—
C4H8N6 + HSO = C4H6NBO + NH,
This compound is also produced by the spontaneous decomposition
of an aqueous solution of cyanogen gas, and by the action of this
gas on aqueous ammonia. When azulmic acid is boiled repeatedly
with water, it is converted into mycomelic acid :—
C4H6NBO 4- H2O = C4H4N4O8 + NH,
Mycomelic acid is a light yellow powder, very sparingly soluble in
cold water, and little more in boiling water. In acids and alkalis it
is freely soluble. Its aqueous yellow solution shows a fine greenish
bine fluorescence, and when dropped into water forms beautiful skyblue
clouds.
Alloxan or Mc$oxalyl-urca C^HgNgOv—Cold nitric acid dissolves uric
acid with evolution of carbon dioxide and nitrogen, and when the
solution is saturated it solidifies to a crystalline moss of alloxan.
Alloxan crystallizes from a warm aqueous solution in crystals
resembling heavy spar, and containing four molecules of water. From
a hot concentrated solution it separates on evaporation in hard
rhombic crystals, containing only one molecule of water. Its aqueous
solution stains the skin red, and confers on it a nauseous smell. Tt
possesses an unpleasant sour-salty taste, and an acid reaction. With
ferrous salts it gives a blue coloration. When alloxan is boiled with
ammonia it is converted iuto mycomelic acid:—
C4H2NaO4 + 2NH8 = C4H4N4Oa + 2H.0
Alloxanic Acid C4H4N2O6.—The salts of this acid are produced by
tlio action of alkalis upon alloxan. It is conveniently prepared by
heating a solution of alloxan and barium chloride with potash
solution, which has to be added gradually until the precipitate formed
does not longer redissolve. On cooling, barium alloxanate separates
out as a crystalline powder, which is decomposed by sulphuric acid.
The acid is readily soluble iu water, aud crystallizes in white needles.
Mesoxalic Acid C3Hj06.—When barium alloxanate is boiled with a
large quantity of water it is resolved into urea and barium iuesoxalate.
This reaction will be easily understood by comparing the following
formula v—
Alloxan. Alloxanic Aci.l, Mesoxalic Acid.
CO—NH CO NH CO.OH
CO CO CO CO CO
!O—NH CO.OH Nit, CO.OH
K 2