The Manufacture and Production of Aromatic Amidoaldehydes.
Year: 1899

page_text: Date of Application, 20th July, 1899
Complete Specification Left. 21st Mar. 1900- Accented 01st Ann
1000
PROVISIONAL SPECIFICATION.
The Manufacture and Production of Aromatic Amidoaldehydes.
I, GEORGE WILLIAM JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Patent Agent, do hereby declare the nature of this Invention (which has been
communicated to me from abroad by C. F. Boehringer and Soehne, of Waldhof, near
Mannheim, in the German Empire) to be as follows:-
As Pellizari (Gazzeta Chimica italiana, 17,412) has shewn, alloxan and aromatic
bases give rise to additive compounds which, under the influence of alkalis, yield acids
containing one carbon atom and one nitrogen atom fewer.
My foreign correspondents have found that these products, both the additive
compounds and the acids obtained from them, are converted into aromatic amidoalde-
hydes when heated with sulphuric acid, losing carbon and nitrogen in the process.
The carbon is eliminated as carbonic acid and carbonic oxide, and thus evolved, whilst
the nitrogen remains dissolved in the sulphuric acid in the form of ammonia.
In this way paradimethylamido benzaldehyde, for example, may be obtained from
dimethylanilalloxan C₁HNO (Gaz. Chim. 17,417), the additive compound of
dimethylaniline and alloxan, as also from the acid CHNO, to which it
gives rise.
The following equations indicate the chance more eventlu.
The amidoaldehydes are thus obtained dissolved in sulphuric acid. The free
aldehydes are readily prepared by neutralising the liquid and then extracting with
ether.
The method according to this Invention gives rise to primary, secondary, and
tertiary, amidoaldehydes, and is capable of very general application. It has been
successful in the case of all those derivatives of benzene which have yet been tested.
By altering the concentration of the sulphuric acid, the temperature of the liquid,
and the proportion of sulphuric acid to base, it is easily possible to determine the
conditions appropriate to individual cases, thus ensuring the preparation of the amido-
aldehydes proceeding smoothly.
The following examples will further explain the process according to this
Invention.
I. PREPARATION OF PARADIMETHYLAMIDOBENZALDEHYDE.
a) From the acid C₁₁₂O
11 12
One part of acid is rapidly stirred into 5 parts of sulphuric acid spec: grav: 1-800
beated at 155°. The acid dissolves with vigorous evolution of gas. If the
temperature be maintained for 10 minutes at 155-160°, the reaction is complete, as
indicated by the absence of gas evolution. The product is then poured into 10
volumes of cold water, and neutralised with sodium carbonate. Paradimethylamido-
benzaldehyde immediately separates in lustrous leaflets, and is removed by filtration,
the remainder being extracted from the liquor by means of ether.
Price R71

page_text: The operation may be carried out with sulphuric acid of very various degrees of
concentration, but an acid of spec: grav: 1.5-1.84 is the most suitable.
b) From dimethylanilalloxan.
The mode of procedure and the course of the reaction agree exactly with those of
the foregoing example if dimethylanilalloxan be employed instead of the acid.
II. PREPARATION OF PARADIETHYLAMIDOBENZALDEHYDE.
One part of diethylanilailoxan is stirred into 5 parts of sulphuric acid spec: grav:
1.8 heated at 155°. Vigorous evolution of gas accompanies the dissolution of the
substance. After 10 minutes the product is poured into cold water, neutralised with
sodium carbonate, and the aldehyde extracted with ether.
On evaporating the ether, para diethylamidobenzaldehyde remains in the form of
an oil which quickly solidifies, and exhibits the recognised properties of the substance
(Ber. d. d. Chem. Ges. 19, 396).
Instead of diethylanilalloxan, the acid obtained from it by the action of alkalies can
be employed.
III. PREPARATION OF PARAMETHYLAMIDOBENZALDEHYDE.
One part of methylanilalloxan is stirred into 5 parts of sulphuric acid spec: gray:
18 heated at 155°. After about 7 minutes the solution is poured into cold water.
It is neutralised with sodium carbonate, and the aldehyde extracted with ether. On
evaporating the ether, methylamidobenzaldehyde remains as an oil which gradually
becomes crystalline. Purification is effected by means of distillation with super-
heated steam. The aldehyde passes over as a yellow oil which rapidly crystallises in
lustrous leaflets on cooling.
It dissolves readily in the usual organic solvents, more sparingly in petroleum.
Paramethylamidobenzaldehyde crystallizes from water in rhombic plates melting
at 60-61°.
The aldehyde is easily taken up by a solution of bisulphite, from which, after
treatment with sodium carbonate, it may be extracted again by ether. On adding
phenylhydrazine acetate to the amidoaldehyde dissolved in water, or in acetic acid,
the hydrazone is precipitated in small, slender needles, which are almost colourless,
and which, when heated, sinter somewhat at 170°, and fuse at 190-192° to a clear
liquid, evolving gas.
In this case also the acid obtained from methyl-anilalloxan can be used instead of
the latter.
1V. PREPARATION OF PARA-ETHYLAMIDOBENZALDEHYDE.
One part of ethylanilalloxan is stirred into 7 parts of sulphuric acid spec: grav: 1-8
heated at 160°. Liberation of gas ceases after 7 minutes. The solution is then
poured into water, neutralised with sodium carbonate, and the aldehyde extracted
with ether. After evaporating the ether the aldehyde remains as an oil which
quickly solidifies. On distilling with superheated steam the aldehyde is obtained as
yellow oil which rapidly crystallises on cooling.
Para-ethylamidobenzaldehyde dissolves very readily in most solvents, but is
sparingly soluble in water and in petroleum. On adding water to the solution in
methylic alcohol the aldehyde is obtained in slender needles.
At 81-82° it melts to an oil which quickly solidifies again on cooling. The
aldehyde readily darkens on exposure to light.
A solution of bisulphite dissolves the aldehyde easily, the latter being regenerated
when sodium carbonate is added to the liquid. The phenylhydrazone forms minute
slender needles, which sinter somewhat at 160°, and melt evolving gas at 182-1849.
In the foregoing example, the acid obtained from ethylanilalloxan can be used
instead of the latter,

page_text: One part of the acid, CH₂N₂O, (Gazz. Chim. 17,413) is rapidly stirred into 9 parts
of sulphuric acid spec: grav: 1-83 heated at 160-170°. If liberation of gas has ceased
at the end of 10-15 minutes, the product is poured into about 10 volumes of water.
A clear solution is obtained on gently warming the liquid which becomes paler when
further heated. The solution darkens when cooled, ultimately precipitating a dark
red salt.
In order to obtain the free aldehyde, the hot solution is neutralised with
sodium carbonate, and the aldehyde is taken up with ether after the liquid has cooled.
On evaporating the ether paramido benzaldehyde remains as an oil which quickly
solidifies. At first the aldehyde dissolves in water, but soon passes into an insoluble
polymeride.
Anilalloxan can be used instead of the acid.
VI. PREPARATION OF PARAMIDOMETATOLUYLALDEHYDE.
One part of orthotoluidilalloxan is stirred into 7 parts of sulphuric acid spec:
grav: 18 heated at 160°. Vigorous effervescence occurs, and the resulting solution
is poured into water after 10 minutes. It is neutralised with sodium carbonate, and
the aldehyde extracted with ether. On evaporating the ether, paramido-meta-
toluylaldehyde is obtained as an oil which crystallises in a few minutes.
heated above 90°, the aldehyde sinters somewhat, and melts at 99-101°.
When
It easily passes into an insoluble polymeride, and closely resembles paramido-
benzaldehyde in other ways (vide D. R. P. of Joh. Rud. Geigy & Cie Basel No. 87255).
Obviously the acid obtained from ortho-toluidilalloxan may be used in preparing
the aldehyde.
VII. PREPARATION OF PARAMIDOMETAMETHOXYBENZALDEHYDE.
One part of anisidilalloxan is stirred into 7 parts of sulphuric acid spec: grav: 1.8
heated at 160°. After 5 minutes the liquid is poured into water, and neutralised
with sodium carbonate. The aldehyde is taken up with ether. On evaporating the
ethereal solution the aldehyde remains as a crystalline mass which at first is scarcely
coloured, but quickly becomes dark red. By dissolution in warm benzene, which
dissolves the colouring matter but sparingly, and precipitation with light petroleum
paramidometamethoxybenzaldehyde is obtained in yellow needles, melting at
101-102°.
Bisulphite solution dissolves the aldehyde readily, the latter being regenerated on
treating the liquid with sodium carbonate. The phenylbydrazone forms minute
slender needles on crystallisation from alcohol, and at 172-174° melts to a clear
liquid, evolving gas. By diazotisation, and decomposition of the diazo-compound,
the aldehyde may be converted into vanillin.
In this case also the acid obtained from anisidilalloxan can be used instead of the
latter.
COMPLETE SPECIFICATION.
The Manufacture and Production of Aromatic Amidoaldehydes.
I, GEORGE WILLIAM JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, 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,

page_text: near 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:-
As Pellizari (Gazzeta Chimica italiana 17,412) has shewn, alloxan and aromatic bases
give rise to additive compounds which under the influence of alkalies yield acids
containing one carbon atom and one nitrogen atom fewer.
My foreign correspondents have found that these products, both the additive
compounds and the acids obtained from them, are converted into aromatic amidoalde-
hydes when heated with sulphuric acid, losing carbon and nitrogen in the process.
The carbon is eliminated as carbonic acid and carbonic oxide, and thus evolved whilst
the nitrogen remains dissolved in the sulphuric acid in the form of ammonia.
13
In this way paradimethylamidobenzaldehyde, for example may be obtained from
dimethylanilalloxan, C₁₂HNO (Gaz. Chin. 17,417), the additive compound of
dimethylaniline and alloxan, as also from the acid, CH₁₂NO, to which it gives rise.
The following equations indicate the change more exactly
12 23
13
C₁₂H₁NO + 2H₂O = CHNO + 2NH3 + 2CO₂ + CO
11

page_text: On evaporating the ether, paradiethylamidobenzaldehyde remains in the form of
an oil which quickly solidifies, and exhibits the recognized properties of the substance
(Ber. d. d. Chem. Ges, 19,396).
Instead of diethylanilalloxan the acid obtained from it by the action of alkalies can
be employed.
III. PREPARATION OF PARAMETHYLAMIDOBENZALDEHYDE.
One part of methylanilalloxan is stirred into 5 parts of sulphuric acid spec: grav: 1.8
heated at 155°. After about 7 minutes the solution is poured into cold water. It is
neutralised with sodium carbonate and the aldehyde extracted with ether. On
evaporating the ether, methylamidobenzaldehyde remains in an oil which gradually
becomes crystalline. Purification is effected by means of distillation with super-
heated steam.
The aldehyde passes over as a yellow oil which rapidly crystallises in lustrous
leaflets on cooling.
It dissolves readily in the usual organic solvents more sparingly in petroleum.
Paramethylamidobenzaldehyde crystallizes from water in rhombic plates inelting
at 60°-61°.
The aldehyde is easily taken up by a solution of bisulphite, from which after
treatment with sodium carbonate, it may be extracted again by ether. On adding
phenylhydrazine acetate to the amidoaldehyde dissolved in water, or in acetic acid,
the hydrazone is precipitated in small slender needles, which are almost colourless,
and which, when heated, sinter somewhat at 170° and fuse at 190°-192° to a clear
liquid, evolving gas.
In this case also the acid obtained from methylanilalloxan can be used instead of
the latter.
IV. PREPARATION OF PARA-ETHYLAMIDOBENZALDEHYDE.
One part of ethylanilalloxan is stirred into 7 parts of sulphuric acid spec: grav: 1.8
heated at 160°. Liberation of gas ceases after 7 minutes.
The solution is then poured into water, neutralised with sodium carbonate, and
the aldehyde extracted with ether. After evaporating the ether the aldehyde
remains as an oil which quickly solidifies. On distilling with superheated steam the
aldebyde is obtained as a yellow oil which rapidly crystallises on cooling.
Para-ethylamidobenzaldehyde dissolves very readily in most solvents, but is
sparingly soluble in water and in petroleum. On adding water to the solution in
methylic alcohol the aldehyde is obtained in slender needles.
At 81° 82° it melts to an oil which quickly solidifies again on cooling. The
aldehyde readily darkens on exposure to light.
A solution of bisulphite dissolves the aldehyde easily, the latter being regenerated
when sodium carbonate is added to the liquid. The phenylhydrazone forms minute
slender needles which sinter somewhat at 160° and melt evolving gas at 1820-184".
In the foregoing example the acid obtained from ethylanilalloxan can be used
instead of the latter.
V; PREPARATION OF PARAMIDOBENZALDEHYDE.
One part of the acid, C,H.NO, (Gazz. Chim. 17,413) is rapidly stirred into
9 parts of sulphuric acid spec: grav: 1.83 heated at 160°-170°. If liberation of gas
has ceased at the end of 10-15 minutes, the product is poured into about 10
volumes of water. A clear solution is obtained on gently warming the liquid which
becomes paler when further heated. The solution darkens when cooled, ultimately
precipitating a dark red salt.
In order to obtain the free aldehyde the hot solution is neutralised with sodium
carbonate and the aldebyde is taken up with ether after the liquid has cooled. On
evaporating the ether paramidobenzaldehyde remains as an oil which quickly
solidifies. At first the aldehyde dissolves in water, but soon passes into an insoluble
polymeride.

page_text: Anilalloxan can be used instead of the acid.
VI. PREPARATION OF PARAMIDOMETATOLUYLALDEHYDE.
One part of orthotoluidilalloxan is stirred into 7 parts of sulphuric acid spec:
grav: 1-8 heated at 160°. Vigorous effervescence occurs and the resulting solution is
poured into water after 10 minutes. It is neutralised with sodium carbonate and the
aldehyde extracted with ether. On evaporating the ether, paramidometatoluyl-
aldehyde is obtained as an oil which crystallizes in a few minutes. When heated
above 90° the aldehyde sinters somewhat and melts at 99°-101°.
It easily passes into an insoluble polymeride and closely resembles paramido-
benzaldehyde in other ways (vide D. R. P. of Joh. Rud. Geigy & Cie Basel, No. 87255).
Obviously the acid obtained from orthotoluidilalloxan may be used in preparing
the aldehyde.
VII. PREPARATION OF PARAMIDOMETAMETHOXYBENZALDEHYDE,
One part of anisidilalloxan is stirred into 7 parts of sulphuric acid spec: grav:
1.8 heated at 160°. After 5 minutes the liquid is poured into water and neutralised
with sodium carbonate. The aldehyde is taken up with ether.
ethereal solution the aldehyde remains as a crystalline mass which at first is scarcely
On evaporating the
coloured, but quickly becomes dark red. By dissolution in warın benzene which
dissolves the colouring matter but sparingly, and precipitation with light petroleum,
paramidometamethoxybenzaldehyde is obtained in yellow needles, melting at
101°-102°.
Bisulphite solution dissolves the aldehyde readily, the latter being regenerated on
treating the liquid with sodium carbonate. The phenyl hydrazone forms minute
slender needles on crystallisation from alcohol, and at 172°-174° melts to a clear
liquid, evolving gas. By diazotisation and decomposition of the diazo compound, the
aldehyde may be converted into vanillin.
In this case also the acid obtained from anisidilalloxan can be used instead of the
latter.
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 I
claim is :-
The manufacture and production of aromatic amidoaldehydes by heating with
sulphuric acid, the additive compounds of alloxan with primary, secondary or tertiary
aromatic bases or the acids obtained from these additive compounds under the
influence of alkalies.
Dated this 21st day of March 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.