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ORGANIC CHEMISTRY.




ALKALOIDS.



187



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r sed as an antiseptic,
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l88 ORGANIC CHEMISTRY.

solvents is the basis of most of the drug-assay processes of
the Pharmacopoeia.

Many alkaloids are bitter, acrid or pungent; most of
them have decided physiological properties and are the
proximate principles upon which the medicinal activities
of the plants containing them depend. A synopsis of
the formulas, sources and characteristics of the principal
alkaloids is given on pages 186, 187.

The alkaloids are distinguished from all other plant
principles by the fact that the aqueous solutions of their
salts are precipitated by the following reagents : potassium-
mercuric iodide, iodine, platinic chloride, auric chloride,
picric acid and tannin. They often produce characteris-
tic color-reactions with the inorganic acids and may be
identified by the concurrence of several of these tests which,
singly, are of little value.

The alkaloids differ from inorganic bases in forming
salts by direct union with the acid, not by substituting
the hydrogen. Thus, morphine forms with hydrochloric
acid the compound C 17 H 19 NO 3 HC1; it is, therefore, called
morphine hydrochlorate (sometimes hydrochloride), not
morphine chloride. This is due to the fact that the alka-
loids are analogous to NH 3 rather than to NH 4 , and the
reaction between morphine and hydrochloric acid is
similar to the reaction NH 3 + HC1= NH 4 C1, in which the
hydrogen is not replaced; in fact, the hydrogen of the
acid may be regarded as combining with the morphine to
form a new molecule, C 17 H 19 NO 3 H, analogous to ammo-
nium and called morphium] the compound formed would
be morphium chloride.

Heroine, C 17 H 17 (C 2 H 3 O 2 )NO 3 , is a diacetyl ester of mor-
phine obtained by synthesis. It is used as a substitute
for morphine.



ALKALOIDS. 189

Daturine, from stramonium (Datura Stramonium), is a
mixture of atropine and hyoscyamine.

The classification of the alkaloids in a group based on
the property of forming definite salts with acids brings
together compounds of very different structure. More-
over, the basic power differs considerably in, different
members of the group. Strychnine, morphine and quinine,
for instance, form stable and definite compounds. Caf-
feine is a weak base, many of its salts being easily decom-
posed.

Several essentially different types of molecular structure
are exemplified in the alkaloids.

Amine type. Betaine is an example of this structure.
Its sources and composition are described under Pto-
maines.

Pyridin type. Many alkaloids are of this type, con-
taining either the simple pyridin ring or the duplicated
(quinolin) ring. When either of these is present, the
molecular structure is stable and the substance resists the
action of many reagents.

Purin type. This is exemplified in caffeine and theo-
bromine. The former is the characteristic alkaloid of tea,
coffee and mat6, and is present in small amount in cacao;
the latter is the principal alkaloid of cacao. Their struc-
tural formulas are given in connection with the descrip-
tions of the Purins.

Hydroxyl and hydrocarbon groups are often present.
The latter can often be oxidised by mild oxidising agents
to carboxyl groups, thus converting the alkaloids into
acids. Several alkaloids, e. g., theophyllin and conine,
have been obtained synthetically. Isomers of quinine
have also been obtained synthetically, but they have not
the medicinal properties of the natural alkaloid.



190



ORGANIC CHEMISTRY.



The annexed structural formulas are in some respects
provisional but they represent atomic arrangements
suggested by the reactions and transformations of the
substances. It will be seen that morphine contains the
phenanthrene ring and no pyridin. It is more easily de-
composed than some other alkaloids. Cocaine and ber-
berine contain the benzene ring; the former contains
asymmetric carbon.

H
H
V3H



H



HO



H 2 C
H 2 C N




Basic nitrogenous bodies occur in, and are produced by,
the decomposition of animal tissues. These are called
ptomaines and leucomaines and are sometimes referred to,
respectively, as the cadaveric or animal alkaloids. They
are described below.



ALKALOIDS. igi

Many artificial alkaloids or allied compounds have
attained prominence in therapeutics during recent years.
Some of these possess the specific power of reducing the
animal temperature, and are collectively known as
antipyretics. They are sometimes called the "coal-tar
synthetics" in recognition of their origin. They are
generally known by trade-names which may be either
abbreviations of their systematic names or purely arbi-
trary. The following are the more important of these:

Acetanilid, antifebrin, C 6 H 5 NH(C 2 H 3 O). This is ob-
tained by the reaction of aniline with acetic anhydride.
It forms colorless and odorless crystals, soluble in 200 parts
of cold water, much more freely in boiling water, alcohol,
ether and chloroform. It is used as an antiseptic dressing
and internally as an antipyretic. It is the basis of several
proprietary antipyretics and is usually present in so-
called "headache powders."

Antipyrin, phenazone, phenyldimethylpyrazolon, C U H 12 -
N 2 O. This is prepared by the action of phenylhydrazin
on ethyl acetoacetate. It forms colorless crystals, freely
soluble in water, alcohol and chloroform.

Phenacetin, acetphenetidin, C 6 H 4 (NHCH 3 CO)OC 6 H 5 .
This is prepared by the action of glacial acetic acid on
paraphenetidin. It forms colorless crystals slightly sol-
uble in cold water, alcohol, ether and chloroform.





ORGANIC CHEMISTRY.





O

C CH 3
I
CH,

Methyl acetanilid Phenacetin

(Exalgin)

Experiment 70. Dissolve o.i gram of quinine sulphate in 10
c.c. of water. Add two drops of bromine water and afterward an
excess of ammonium hydroxide. The liquid will assume a bright
emerald-green color. This is known as the thalleioquin reaction
and will also be given by quinidine or its salts.

Experiment 71. Dissolve .02 gram of morphine sulphate in
2 c.c. of water and add several drops of solution of ferric chloride.
A blue color will be produced which is destroyed by heating.

Experiment 72. Add a small quantity of morphine or one of
its salts to a drop of nitric acid upon a porcelain surface. An
orange-red color will be produced which rapidly fades.

Experiment 73. Dissolve .01 gram of strychnine in about 5 c.c.
of water and transfer the solution to a small separatory funnel.
Add about 2 c.c. of chloroform and then render the aqueous liquid
alkaline with sodium carbonate. Upon shaking the separatory
funnel the liberated alkaloid enters into solution in the chloroform,
which may be drawn off, evaporated, and the residue tested as
under Experiment 74.

Experiment 74. Dissolve a minute quantity of strychnine, or
one of its salts, in a few drops of concentrated sulphuric acid on
a white porcelain or glass surface, and add a small crystal of potas-
sium dichromate. Upon stirring the crystal of dichromate around
with a glass rod a blue color will be at first produced, which changes
to purplish blue and gradually fades through red to yellow. Ceroso-
ceric oxide, manganese dioxide or similar oxidising agents will
produce the same effect as potassium dichromate.

Experiment 75. Rub together 4 parts of hydrastine and i part
of morphine and treat a minute quantity as in Experiment 74. A



PTOMAINES AND LEUCOMAINES. 193

color similar to the strychnine will be produced, which does not
fade out as rapidly but is more permanent. Tests with morphine
and hydrastine separately will fail to show any color.

Experiment 76. Heat a small quantity of atropine with several
c.c. of sulphuric acid. A peculiar aromatic odor is evolved re-
calling a mixture of rose and orange flower. Add a small frag-
ment of potassium dichromate and the odor will change to that of
bitter almond oil.

Experiment 77. Add a small amount of colchicine to a drop of
nitric acid on a white porcelain or glass surface. A blue color will
be produced which fades in a short time.

Experiment 78. Rub a small quantity of veratrine with a few
drops of sulphuric acid on a white porcelain or glass surface and
observe the intense red color which is produced, which does not
fade even after several hours.

Experiment 79. Dissolve a small quantity of caffeine in a few
drops of hydrochloric acid, add a few small crystals of potassium
chlorate and heat over a water bath until a dry residue remains.
Expose the residue to the vapor of ammonium hydroxide and
observe the characteristic rich purple color which it assumes.
This is known as the murexid test. Uric acid will give the same
reaction, being closely analogous in structure to caffeine.



PTOMAINES AND LEUCOMAINES.

The chemical changes classed under the terms fermen-
tation and putrefaction are caused by living organisms,
mostly very minute, and included under the general title
"microbes." It seems probable that all such transfor-
mations are due to enzyms. The principal action is the
breaking down of complex nitrogenous ingredients of the
living tissues, often by hydrolysis, but also by other types
of action, especially oxidation when the action occurs in the
presence of air. It follows, therefore, that if air be ex-
cluded, the chemical changes will be somewhat different,
and hence a distinction is made between the usual (aerobic)
decompositions and those that occur out of contact with
13



194 ORGANIC CHEMISTRY.

free oxygen (anaerobic). The latter class has not been as
yet extensively studied.

The products of aerobic fermentation and putrefaction
have been of late studied with great zeal. Many of them
are distinctly basic resembling the alkaloids. Further-
more, the normal pathologic processes of animals give rise
to basic bodies. It is hardly necessary to distinguish
these different classes, but such distinction has been made.
The basic bodies produced by microbes are called "pto-
maines," those produced in animals, "leucomaines"
The latter term is not much used. Care must be taken
not to confuse the products of animal tissues (leucomaines)
with the products of microbes inhabiting the tissues,
fluids or cavities of animals. The latter are ptomaines,
for they are the result of fermentation or putrefaction
apart from the vital action of the animal. As such result-
ing bodies cause disease by absorption into the fluids of the
animal they are sometimes termed ''toxins." By special
methods, bodies (antitoxins) antagonistic in physiologic
effect can be obtained and used in the treatment of diseases
caused by toxins.

Microorganisms either directly or by intermediate action
of enzyms, may produce alcohols, acids, neutral substances,
cyclic compounds and nitrogenous derivatives; in fact,
representatives of any class of organic compounds. The
term ptomaine is derived from a Greek word meaning a
dead body, and following out the analogy we might apply
the same term to all the products of the decomposition of
organic bodies under the influence of microorganisms,
distinguishing the different classes by the proper ter-
minations. Thus ptomols would be alcohols, produced
by such action. Lactic and butyric acids are ordinarily
produced by the action of microbes and are therefore
ptomic acids.



PTOMAINES AND LEUCOMAINES. 195

It is to be noted, therefore, that the ptomaines are
not peculiar as a class among basic organic bodies, nor
are they the only products of decompositions.

All ptomaines contain nitrogen, but the relation of
this to the other atoms is dependent on the nature of the
original molecule and the microbes or enzyms which
bring about the transformation. Of the different types
of combination that nitrogen may exhibit, amido-, azo- and
diazo-groups are the most common. Pyridin compounds
are not usual among the products of ordinary putrefaction ;
nitro- and nitroso-groupings are never observed.

The amines observed range in complexity from true
basic monamines to tetramides with acid function.

Of the simpler type are some common ptomaines, such
as putrescine, N 2 H 4 (CH 2 ) 4 , tetramethene diamine, and
cadaverine, (NH 2 )(CH 2 ) 5 , pentamethenedia'mine. A syn-
thetic product used in medicine is also of analogous struc-
ture, piperazin, diethenediamine, N 2 H 4 (C 2 H 4 ) 2 . Similar
but more complicated bodies are indicated in the annexed
structural formulas. They are of the general type of the
true bases and it will be seen that alcoholic and acid
groupings are also represented.

H 3 C H H H 3 C H H

N

Li I I I -n-s I

O H H O

i.;: : : i

Choline Neurine

Choline. Salts of this base occur in many animal and
vegetable tissues. It was originally extracted from bile



196 ORGANIC CHEMISTRY.

to which the name refers. Its glycerophosphate exists in
lecithins. As will be seen from the structural formula
it is a complex derivative of ammonium hydroxide. It is
strongly alkaline, absorbing water and carbon dioxide
from the air. It forms a crystalline chloroplatinate.

Neurine. This is obtained by boiling choline with
barium hydroxide and is produced in some putrefactions.

Muscarine occurs associated with choline in poisonous
mushrooms.

Betaine occurs in the sugar beet and is also produced
by the cautious oxidation of choline.

H 3 C H H H 3 C

C C O H |

I Ais^-

* H A H

H H

Muscarine Betaine

PURINS. Alloocuric bodies, Xanthin bases. Under these
terms, the first being now much in vogue, is included a
number of bodies of complex structure which it has been
proposed to regard as derived from a hypothetical radicle
termed the "purin nucleus." From this, by association
with other radicles, such as amidogen, imidogen, hydroxyl
and carbonyl, formulas of the members of the series may
be obtained. The following formulas show the relations
of some of the members of the series to the purin nucleus
and to purin itself:

N=C N=CH

C C N HC C-NH

II II \ II \

N_C-N=C N-C N=C

Purin nucleus Purin



PTOMAINES AND LEUCOMAINES. IQ7

It will be seen that purin is, in a measure, a duplicated
urea, the oxygen being absent and part of the hydrogen
replaced by carbon. The purin bodies are at present
attracting much attention owing to their supposed relation
to animal nutrition and metabolism. They exist in
many foods and abundantly in tea, coffee, mate and cacao.

The following table gives the empirical formulas of
some members of this group, and a few structural for-
mulas are annexed:

Uric acid C 5 H 4 N 4 O 3

Xanthin C 5 H 4 N 4 O 2

Hypoxanthin C 5 H 4 N 4 O

Paraxanthin C 7 H 8 N 4 O 2



Theobromine C 7 H 8 N 4 O 2

Caffeine C 8 H 10 N 4 O 2

Adenine Q>H 5 N 5

H N C H H 3 C N C H

I II I II

= C C N H = C C N CH 3

I I \ I I \

H N C=N C H N C=N C

II II

o o

Xanthin Theobromine

H N C=O H 3 C N C H

II I II

= C C N H O=C C N CH 3

I II \ I I \

H N C N C=0 H 3 C N C=N C=O

A

Uric acid Caffeine



IQ8 ORGANIC CHEMISTRY.

Of these bodies caffeine and theobromine are described
in connection with the group of alkaloids in which they
are usually classified, but they possess only feebly basic
properties, and their formulas are structurally very
different from those in the majority of that group.

Uric acid, trioxypurin, C 5 H 4 N 4 O 3 . This occurs in small
amount in the urine of mammals and abundantly in that
of birds and reptiles. It can be obtained by strongly
acidulating urine with hydrochloric acid and allowing the
mixture to stand for some hours. Uric acid separates
as a crystalline precipitate, usually brownish, from ad-
herent coloring matter. When pure it is in colorless
crystals, almost insoluble in cold water and only slightly
soluble in boiling water. It forms several derivatives with
sodium, potassium and ammonium, usually called ' ' urates, ' '
which are more soluble in water than the acid itself.
Uric acid does not contain the carboxyl radicle, but the
group HNCO, which occurs thrice in the molecule, confers
nominal acidity.

Xanthin, dioxypurin, C 5 H 4 N 4 O 2 . This occurs in small
amount in urine, but is more abundant in flesh juice, hence
is found in commercial meat-extract. It is colorless,
crystalline and nearly insoluble in cold water. It is
dissolved by alkaline solutions.

Hypoxanthin, oxypurin, C 5 H 4 N 4 O 2 . This is found as-
sociated with xanthin. It is crystalline and but slightly
soluble in cold water.

Paraxanthin, dimethylxanthin, C 7 H 8 N 4 O 2 , is isomeric
with theobromine.

Adenine, amidopurin, C 5 H 5 N 5 . This occurs in several
animal fluids, but is most abundant in tea-leaves. It
contains no oxygen.

Purin bodies are without nutritive value to the higher



PTOMAINES AND LEUCOMAINES. IQQ

animals, hence any that are present in the food are passed
off as promptly as possible by the excretions. The or-
dinary waste of tissue (destructive metabolism) in the
animal produces purins, hence the excretions will contain
both those in the food and those formed in the body. The
former are termed ''exogenous purins," the latter "en-
dogenous purins."

Many analyses of food stuffs have been made in order-
to determine the amount of purins, so that the diet may be
regulated to secure the minimum amount of exogenous
purins when these are especially objectionable. Meats,
some wines and cereals contain considerable amounts of
purins; milk, eggs and cheese small amounts. Compara-
tively few natural purins have been isolated, but over one
hundred derivatives have been prepared synthetically.

The endogenous purins are regarded as derived largely
from the nucleoproteids by successive dissociation, with
probably both hydrolysis and oxidation under the influ-
ence of enzyms. If these processes be carried to a con-
siderable extent, as occurs when the functions of nutrition
and excretion are well balanced, the purin derivatives are
mostly converted into a simple diamido-compound urea,
which constitutes the principal result of the waste of
nitrogenous tissues in the higher animals and is the most
abundant solid ingredient of normal human urine.

Urea and some closely related excretory substances are
described elsewhere.



PROTEIDS OR ALBUMINOIDS.

Proteids or albuminoids are complex bodies that form
the essential portions of living tissues. They all contain
hydrogen, oxygen and nitrogen; most of them contain
also sulphur; a few contain phosphorus, and a few con-
tain iron. Even copper has been found in some, and it is
not unlikely that elements, not usually existing in natural
organic bodies, are present in proteids having highly
specialised function or developed under exceptional con-
ditions.

Little is known as to the structural formulas of proteids,
except that they are all very complex, containing open and
closed carbon chains. The nitrogen is probably in a
pyridin ring and partly in a cyanogen or amine form.
Some authorities distinguish between proteids and al-
buminoids, limiting the latter term to gelatin and closely
analogous bodies. Other authorities limit the term
proteid to substances that yield monamido-acids on de-
composition by certain processes. These distinctions,
however, can not be regarded as final, and it is sufficient
for present study to classify a considerable number of
bodies under the general terms here used, even though
appreciable differences in properties are noted. The
proper classification will be made when the rational
formulas become known.

Proteids are generally colorless or faintly yellow amor-
phous solids, soluble in water, but some require for this
purpose the coincident presence of certain salts. Some
proteids dissolve in alcohol. Water solutions putrefy



PROTEIDS OR ALBUMINOIDS. 2OI

promptly, under ordinary conditions, but this is merely
the result of the action of microbes. In the presence
of antiseptics or in sterile solution proteids are practically
permanent. They are ordinarily eminently colloid, hence
have very low diffusive power, but one proteid .has been
obtained in a distinctly crystalline form, and there is no
reason to doubt that all of them are capable of crystal-
lising under certain conditions. Solutions of proteids have
marked levorotatory power,

A satisfactory classification of proteids is impossible
in the present imperfect state of knowledge. In many
cases several bodies are probably included under one name ;
in other cases a supposed natural proteid is a product
of the methods employed in obtaining it. The classi-
fications usually followed take but little account of vege-
table proteids, although these are quite numerous. The
following classification is that of Hammarsten; it is merely
an incomplete index to the animal proteids.

Simple proteids or albumins:

Albumins proper: Ovalbumin, seralbumin, lactalbumin.

Globulins: Fibrinogen, vitellin, myosin, crystallin.

Nucleoalbumin : Casein.

Albuminates : Acid albuminate, alkali albuminate.

Albumoses.

Peptones.

Coagulated proteids: Fibrin, coagulated albumins.

Compound proteids :

Hemoglobins.

Glyco-proteids : Mucins, hyalogens, amyloid.
Nucleoproteids : Nucleohiston, cytoglobin.
Albuminoids: Keratin, elastin, collagen.

Many proteids are precipitated from their solution in
water, in forms that are not capable of re-solution without
chemical change. This, which is termed "coagulation,"



202 ORGANIC CHEMISTRY.

is brought about by heat in some cases, by different chem-
ical agents in others; each proteid requiring particular
methods. When quite dry, proteids show little tendency
to change. By strong heating they are converted in a
mixture of substances, among which pyridin and some
of its derivatives are especially noticeable.

Coagulated Proteids. Under this term are included
proteids rendered insoluble in their normal solvents, pure
water or saline solutions, as the case may be. In some
cases they may be identical with the original body, but
in most cases they are probably modified either by hydroly-
sis or. oxidation with or without division into two or more
new substances. Most of them can be converted into
proteoses and finally into peptones by the action of some
enzyms, and on this fact depends the digestibility of many
articles that are prepared by cooking, by which the pro-
teids are coagulated.

ALBUMINS PROPER. This group, includes ovalbumin
(egg albumin), ser albumin (blood albumin) and lactalbumin
(milk albumin). Care must be taken not to confuse
''albumin" with "albumen." The latter term refers to
the nutritive material surrounding an embryo. It con-
tains one or more proteids which may or may not be
albumins. White of egg is the "albumen" of the egg.
It contains ovalbumin, water and other bodies. The
seeds of many plants contain a large amount of material
around the embryo. This is called the "albumen" of the
seed. In the common cereals this albumen contains
several proteids, with much starch and some fatty matter


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