The Manufacture or Production of Acid Compounds Derived from Gallic Acid Anhydrides.
Year: 1894

page_text: Date of Application, 19th Jan., 1894
Complete Specification Left, 19th Oct., 1894-Accepted, 12th Jan., 1895
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBENFABRIKEN, vormals FRIEDRICH
BAYER & Co., of Elberfeld, in the Empire of Germany.]
The Manufacture or Production of Acid Compounds Derived from
Gallic Acid Anhydrides.
I HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention to be as follows :-
It is known that the use of tannin, as an internal medicine is attended with ill
effects, as it is soluble, and, by its tanning action, greatly affects the stomach. It
was therefore of importance to make use of only such tannin compounds, or the
like, as were insoluble, and which, whilst passing the stomach without any
decomposition, would only be dissolved by the alkaline liquid of the intestines,
tannin being again formed. It is evident that the last defined products would show
the action of tannin, and at the same time would be destitute of the ill effects
produced by tannin.
The acid derivatives hitherto known, that is to say, the penta acetylated
derivatives of digallic acid, which result from heating digallic acids with an excess
of acetic anhydride, as described by Schiff (Annalen der Chemie und Pharmacie,
volume 170, page 68), and Bottinger (Berichte der Deutschen Chemischen
Gesellschaft, volume 17, page 1478) have been found to be entirely ineffective,
which no doubt is owing to the fact that the said penta-acetylated compounds are
insoluble in dilute alkalies, and likewise in the intestinal liquid, and by reason
thereof are not decomposed in the body, so that digallic acid is formed again.
My foreign correspondents have now found, that the mono or di acid derivatives
of gallic acid anhydrides entirely answer the demands herein before set forth. By
the above
"
expression, mono or di acid derivatives of gallic acid anhydrides," my
foreign correspondents mean, for instance, the following products, viz. :-mono-
acetylated gallic acid anhydrides, diacetylated gallic acid anhydrides, or the
corresponding mono- or di-propionyl compounds, nono or di-valeryl products, mono
or dibenzoyl products, mono or di-salicylic compounds. These mono or di-acid
derivatives are insoluble in water, and are not altered by dilute acids at low
temperatures, whereas they dissolve in dilute cold alkaline liquids, first without
any decomposition, and only after a long period are converted into gallic acid
anhydrides or the like. Owing to these properties, the above defined compounds
do not affect the stomach, and only act when they come into the intestines. The
action of these products, when used in chronic catarrhal affections of the intestines,
is of special value.
The production of these mono or di-acid derivatives in general, is effected by
treating gallic acid anhydrides, in or without the presence of a solvent or diluent,
with a slight excess of the respective arid anhydrides, acid chlorides, or acids,
with or without the addition of a so-called "condensing means," such as phosphorous
chlorides, phosphoroxy-chlorides, melted sodium acetate, acid alkali salts of
sulphuric acid, or the like.
Of gallic acid anhydrides, my foreign correspondents use, for instance, alpha
and beta digallic acid, the natural tannic acids derived from gallic acid, and
the Tika
:

page_text: In order to illustrate one of the methods of producing these mono or di-acid
derivatives, the following example is given, the parts being by weight.
EXAMPLE.
1 part of dry tannin is mixed with part of glacial acetic acid, and 1 part of
acetic acid anhydride, and the resulting mixture is heated. The tannin gradually
dissolves, and after from about 6 to 7 hours, the dark. mass so formed is poured in a
thin stream, and with continuous stirring, into water, a resinous mass being thus
separated. This mass is stirred with water during a prolonged period, profitably
using fresh water for every single operation. The resinous mass is, by this
treatment, converted into a light yellow powder, which is filtered off, and whilst
on the filter, is washed with water, until the washings show no color.
The product so formed is a mixture containing chiefly the mono aceto compound,
together with small quantities of the diaceto compound. It is amorphous, soluble in
alcohol, insoluble in water and dilute acids, soluble in cold dilute alkalies, and can
be precipitated in an unaltered state by acidulating its alkaline solutions. On
heating with alkalies, it undergoes decomposition.
The proportion of the diaceto compound contained in the acetylated product, is
increased by using a greater quantity of acetic anhydride.
Other acid derivatives result in an analogous manner, if the mixture of glacial
acetic acid and acetic acid anhydride, is replaced by other acetylating agents (such
as acetyl chloride), or other acid anhydrides or acid chlorides (such as propionic
acid anhydride or propionic acid chloride, valerianic acid anhydride, or valerianic
acid chloride, beuzoic acid anhydride, or benzoyl chloride, or the like), or by the
free acids (such as salicylic acid, benzoic acid, or the like), with or without the
addition of a suitable condensing means.
The products thus obtained in general show great similarity with the acetylated
product produced as described in the above example.
Dated this 18th day of January 1894.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
The Manufacture or Production of Acid Compounds Derived from
Gallic Acid Anhydrides.
I, HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
It is known, that the use of tannin as an internal medicine is attended with ill
effects, as owing to its solubility, it exerts a tanning action on the stomach. It is
therefore important to make use of only such insoluble tanni compounds, or the
like. as will pass through the stomach without undergoing decomposition, and will
yield tannin only when dissolved by the alkaline fluid of the intestines.
Such products would exhibit the action of tannin, but at the same time would be
destitute of its prejudicial properties.
The acid derivatives hitherto known, that is to say, the pentacetylated derivatives
of the digallic acids which are produced on heating digallic acids with an excess of
acetic anhydride, as described by Schiff in the Annalen der Chemie and Pharmacie,
volume 170, page 68, and by Böttinger in the Berichte der Deutschen Chemischen
Gesellschaft, volume 17, page 1478, and the benzoylated tannin described by

page_text: 1 part of dry tannin is mixed with a part of glacial acetic acid, and 1. part of
acetic anhydride, and the mixture is heated. The tannin gradually dissolves.
After from about 6 to 7 hours, the dark mass is poured in a thin stream into water,
which is continuously stirred. A resinous mass separates, which is purified by
washing with water, until it is converted into a light yellow powder, the water
with which the mass is kneaded being frequently changed. The powder is filtered
off and washed on the filter with water, until the washings shew no colour.
The product is a mixture consisting chiefly of the monacetyl, together with
small quantities of the diacetyl derivative. It is an amorphous substance, soluble
in alcohol, insoluble in water and dilute acids, but soluble in cold dilute alkalies.
It is precipitated in an unaltered state on acidulating its cold solutions in alkaline
carbonate, but on heating it with alkalies, it undergoes decomposition.
The proportion of diacetyl derivative contained in the acetylated product is
increased by using a larger quantity of acetic anhydride.
Other similar acetyl derivatives are formed in a manner analogous to that
described in the preceding example, if, instead of tanuin, analogous anhydrides,
such as alpha or beta digallic acid, are used, and instead of the mixture of glacial
acetic acid and acetic anhydride prescribed in this example, other acetylating
agents, such as acetyl chloride, or glacial acetic acid, can be used. Suitable
condensing agents may be used if desirable.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed (as communicated to me
from abroad), I declare that what I claim is :-
1. The process for producing monacetyl and diacetyl derivatives, soluble in
alkalies, from gallic anhydrides, which process consists in treating gallic anhydrides,
such as tannin, alpha or beta digallic acid, alone, or in presence of a solvent or
diluent, with acetic anhydride, acetylchloride, or acetic acid, or other acetylating
agents, adding a condensing agent if desirable.

page_text: 2. As new products of manufacture, the new monoacetyl and diacetyl compounds
produced by the process hereinbefore defined, or by any other means affording
the same result.
NEWTON & SON,
Agents for the Applicant.