The Manufacture and Production of Formic Aldehyde Compounds of Uric Acids and Alkyl-uric Acids.
Year: 1898

page_text: Date of Application, 27th Sept, 1898-Accepted, 17th Dec., 1898
COMPLETE SPECIFICATION.
The Manufacture and Production of Formic Aldehyde Compounds
of Uric Acids and Alkyl-uric Acids.
I, GEORGE WILLIAM JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, Chartered Patent Agent, do hereby declare the nature of this invention,
which has been communicated to me from abroad by C. F. Boehringer & Soehne, of
Waldhof, Mannheim, in the German Empire, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:
This invention relates to the preparation of compounds of formic aldehyde and
uric acids the said invention extending to such combinations of formic aldehyde not
only with uric acid proper, but with homologues, or alkyl-derivatives of the same, all
of which are classed under the generic designation " uric acids."
My foreign correspondents have found that products of consolidation can be
formed from uric acids and formic aldehyde in which one molecular proportion of the
acid has combined with one molecular proportion only of the formic aldehyde.
Compounds of this new class are obtained by causing formic aldehyde to act upon
a uric acid in combination with alkali, either in the formn of an alkaline solution of
the acid, or an alkali-salt of the same. This reaction appears to result generally
whether the uric acid proper, or alkylized uric acids, be employed.
My foreign correspondents have thus far obtained such consolidation products with
formic aldehyde from uric acid proper, 3-monomethyl-uric acid, 7-monomethyl-uric
acid, 9-inononethyl-uric acid and 1-3-dimethyl-uric acid.
In these new products the carbon-atom of the formic aldehyde is directly bound
to a nitrogen-atom of the uric acid, and it is probable that an oxymethylene-com-
pound has been formed according to the following formula:
That a nitrogen-carbon-combination is effected is established by the fact that the
new bodies obtained according to the present invention are, by reduction, readily and
smoothly converted into alkylized uric acids:
R.N. CH₂. OH + H₂
=
R.N. CH₂ + H₂O.
Each of these oxymethylene-uric acids, formed by the union of uric acids and
formic aldehyde, easily split off formic aldehyde on boiling them with water, dilute
mineral acids, or alkalies, the corresponding uric acids being regenerated. So far as
they still contain free imido-groups, they may be readily further alkylized.
In order to fully explain the process according to this invention, and the products
thereof, the following examples are given, embodying what is considered the pre-
ferable manner of carrying the invention into effect.
Unless otherwise stated the parts are by weight.

page_text: One part of uric acid, proper, is dissolved in fifteen parts of water, together with
one part (corresponding to two and one half molecular proportions) of caustic potash,
of 80 per cent. strength, while gently warming. The solution is then allowed to
cool to ordinary room temperature, and 1-6 parts of concentrated solution of formic
aldehyde are then added thereto. The whole is then allowed to stand at room tem-
perature. After the lapse of several hours (usually from 20 to 25 hours) the
still, clear, solution is acidulated with HCl. and treated with charcoal by
agitation.
After filtering the liquor, the colourless filtrate is allowed to stand, when the
oxymethylene-uric acid will be precipitated in the form of coarse shining, prismatic
crystals, which are then cleaned by washing with alcohol and ether and drying on
the water-bath. The analysis of these crystals gives figures corresponding to the
formula
The water of crystallization is slowly driven off by heating for a longer period at a
temperature of from 120 to 130 degrees Centigrade. The oxymethylene-uric acid,
like uric acid proper, gives a strong inurexide test with nitric acid, or chlorine water,
and reduces ammoniacal silver solution in the cold.
The new product has no melting point, but turns brown when heated beyond
320 degrees Centigrade, and is decomposed at a still higher temperature, the decom-
position being attended by darkening and frothing.
It is readily recrystallized from water by boiling a short time after adding it
thereto. It is thus obtained in the form of fine acicular crystals, or short colourless
prisms.
On protracted boiling with water, formaldehyde is split off and the uric acid
proper regenerated.
Oxymethylene-uric acid is readily soluble in dilute alkalies. Concentrated alkali-
lyes after a short time precipitate the corresponding salts in the form of colourless
needles united to form globular aggregates.
The potassium salt of oxymethylene-uric acid may readily be obtained from crystal-
lized acid urate of potassium if the latter be added to five times its weight of concen-
trated solution of formic aldehyde and the whole allowed to remain together for a
considerable period, say about thirty to forty hours, the whole being preferably
agitated. The excess of formaldehyde solution is then removed by siphoning;
decanting, or otherwise, and then washing with alcohol. From the potassium-salt,
so obtained, the above described oxymethylene-uric acid is obtained by super-
saturating with mineral acids.
To one part of 3-monomethyl-uric acid is added 1-8 parts of potash-lye, (potassium-
hydrate), of 20 per cent. strength, and one part of a concentrated solution of formie
aldehyde and the whole is shaken until a clear solution results, which occurs in a
short time. After allowing this solution to stand for about 15 to 20 hours at room-
temperature, the liquor is acidulated with hydrochloric acid. The crystallization of
the (3) methyl-oxymethylen-uric-acid in the form of colourless cystals begins. After
cooling the mass for several hours with ice water, the liquor is removed from the
crystal which may be done by decanting siphoning or the like.

page_text: The analysis of the crystalline powder so obtained, after being dried in an exsiccator,
or in any suitable manner, gives figures corresponding to the formula
This new compound is readily soluble in boiling water, crystallizing therefrom in
the form of colourless prisms, for the most part aggregated in druses, or nodules. . On
boiling for a longer period formaldehyde escapes and 3-methyl-uric acid is regenerated..
It. possesses no melting point, but is decomposed between 310 and 320 degrees
Centigrade, this action being accompanied by darkening and effervescence, or frothing.
It gives the murexide test, and reduces ammoniacal silver solutions, even when gently
heating.
3-methyl-oxymethylene-uric acid is readily soluble in dilute alkalies, including
ammonia, and also in fuming hydro-chloric acid.
EXAMPLE III.
PREPARATION OF 1-3-DIMETHYL-OXYMETHYLENE-URIC-ACID.
Over one part of 1-3-dimethyl-uric-acid are poured 3.5 parts by volume, of
double normal potash-lye. This causes solution of the acid. After a short time;
however, the whole congeals to a pulp or mass, of. fine acicular crystals, consisting of
the potassium-salt of the 1-3 dimethyl-uric acid. One part of concentrated solution
of formic aldehyde is now added which rapidly results in the formation of a clear
solution. This solution is allowed to stand, and, after some time the potassium salt
of the 1-3-dimethyl-oxymethylene-uric acid is separated as a colourless crystalline
mass, consisting of small needles aggregated into globular masses. After allowing this
crystalline mass to stand for about thirty hours, the liquor is drawn off therefrom and
the crystalline mass is dissolved in water and acidulated with hydrochloric acid.
The crystallization of the free 1-3-dimethyl-oxymethylene-uric acid in the forin of
colourless fine needles then begins. After cooling the mass for several hours with
ice-water, the liquor is drawn off from the crystals by siphoning, decanting, or
otherwise. An analysis of these crystals after being dried by means of the exsiccator
gives figures corresponding to the formula

page_text: The new product is, moreover, soluble in dilute alkalies, including ammonia, and
also, in concentrated bydrochloric acid.
It has no melting point, but on heating to over 300 degrees Centigrade it is
gradually decomposed, the decomposition being attended by darkening.
When employing the alkylised uric acids as starting materials, the corresponding
oxymethylene compounds may also be obtained if the formic aldehyde be added to a
neutral, instead of an alkaline, solution of such alkyl-uric acid. For these uric
acids, the generic feature of the process is the addition of formic aldehyde to an
aqueous solution, or suspension of alkyl-uric acid heating the mixture for several
hours to about 100 degrees Centigrade till a clear solution is formed, evaporating the
same to dryness and recrystallising the residue froin hot water.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed I declare that what 1
claim is :-
1. The manufacture, or preparation, of formic aldehyde compounds of uric acid,
or alkyl-uric acids, by causing formic aldehyde to act upon a uric acid combined
with an alkali.
2. The manufacture or preparation of formic-aldehyde compounds of alkyl-uric
acids by causing formaldehyde to act upon an aqueous solution of an alkyl uric
acid.
3. As a new series of compounds, oxymethylene uric acids each of which is the
derivative of a uric acid in which the hydrogen of one of the imido groups is replaced
by the group C.H., O.H., each of which decomposes at a higher temperature which
are soluble in water and easily soluble in alkalies, which yield up formic aldehyde on
boiling with water, dilute mineral acids or alkalies, which all are converted into
alkylised uric acids by reduction.
877 Jan of Contaohan 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.