Org. Synth. 1932, 12, 84
Submitted by W. W. Hartman and O. E. Sheppard.
Checked by C. S. Marvel and B. H. Wojcik.
In a 5-l. flask
are placed 100 g. (0.44 mole) of nitrobarbituric acid (p. 440)
and 600 cc. of concentrated hydrochloric acid
, and the mixture is heated on a boiling water bath
. To the hot mixture are added 250 g. (2.1 gram atoms) of mossy tin
and 400 cc. of hydrochloric acid
over a period of about thirty minutes; heating is continued until there is no yellow color in the liquid (Note 1)
. The solution is treated with about 3 l. more of concentrated hydrochloric acid
and heated until all the white solid is in solution. Norite
is added, and the hot mixture is filtered through a sintered-glass funnel (Note 2)
. The filtrate is allowed to stand in an icebox
overnight, and then the precipitate (Note 3)
is collected on a filter and washed with liberal quantities of dilute hydrochloric acid
and finally with water (Note 4)
. The filtrate is concentrated under reduced pressure to about 1 l. and cooled overnight. The additional uramil
thus obtained is collected on a Büchner funnel
and added to the first product (Note 5)
. The uramil
is dried in a desiccator
over concentrated sulfuric acid
, and finally over 40 per cent sodium hydroxide
to remove hydrochloric acid (Note 6)
Uramil is a fine, white powder which becomes pink to red on standing. The yield of a product which does not melt below 400° is 40–46 g. (63–73 per cent of the theoretical amount).
forms a yellow aqueous solution, but, as the color is weak in concentrated hydrochloric acid
solution, no trace of it should show at the end of the reaction.
If a sintered-glass funnel
is not available, the solution may be filtered through a half-inch layer of decolorizing carbon
on a double filter paper
. After the uramil
is once dissolved in the concentrated hydrochloric acid
it comes out of solution very slowly, and, if filtered promptly, the solution may be cooled to 60–80° with little loss of product.
If, as happens occasionally, the uramil
does not crystallize, the solution must be concentrated and cooled again.
Unless the product is washed thoroughly it will contain tin salts.
To test for uramil
an ammoniacal solution is boiled in the air. A positive test is the appearance of a pink color which gradually grows deeper. The reaction proceeds more rapidly in the presence of mercuric oxide
If the material is dried in the air or in an oven, a pink product is almost always obtained. The pink color is produced more rapidly if ammonia
or amines are present in the air.
has been obtained by boiling alloxantin
with ammonium chloride
by reduction of nitrosobarbituric acid
or nitrobarbituric acid
with hydrogen iodide
and by reduction of alloxan phenylhydrazone
and hydrochloric acid
Chemical Abstracts Nomenclature (Collective Index Number);
dilute hydrochloric acid
sulfuric acid (7664-93-9)
hydrochloric acid (7647-01-0)
ammonium chloride (12125-02-9)
sodium hydroxide (1310-73-2)
mercuric oxide (21908-53-2)
hydrogen iodide (10034-85-2)
Nitrobarbituric acid (480-68-2)
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