Note: Descriptions are shown in the official language in which they were submitted.
~6~5~34~
The present invention relates to adenosine nitrates. More
particularly, the present invention is concerned with adenosine nitrates, a
process for the manufacture thereof and pharmaceutical preparations contain-
ing same.
The adenosine nitrates provided by the present invention are
compounds of the general formula:
NIH2
~ /
r(5- ~ o (1~
H~l :
;
wherein Rl and R represent a hydrogen atom or a nitro group with at least
one of Rl and R2 representing a nitro group; and R5 represents a hydroxy,
lower alkoxyJ amino, ~lower alkyl)amino, di-~lower alkyl)amino, [di-~lower
alkyl)amino-~lower alkyl)]amino, ~nitrato-lower alkyl)amino, aryl-~lower
alkyl)amino or cycloalkylamino group or a nitrogen~containing heterocyclic
ring which is bonded via a nitrogen atom, and physiologically acceptable acid
addition salts thereof.
In this specification, the expressions "lower alkyl" and
"lower alkoxy" include straight-chain or branched-chain groups containing
1-6 carbon atoms ~e.g. methyl, methoxy, ethyl, ethoxy, propyl, propoxy, iso-
propyl, isopropo~y, sec~butyl, sec.butoxy, tert.butyl and tert.butoxy).
Examples of ~lower alkyl)amino and di-~lower alkyl)amino groups are methyl-
amino, ethylamino, propylamino, butylamino~ dimethylamino, diethylamino anddiisopropylamino~ Examples of aryl-~lower ~kyl)amino groups, of which the
phenyl-tlower alkyl~amino groups are preferred, are the benzylamino~land 1-
and 2-phenethylamino groups. The cycloalkylamino groups are especially those
which contain up to 7 carbon atoms (e.g. cyclopentylamino and cyclohexylamino).
The nitrogen-containing heterocyclic ring which is bonded via a nitrogen atom
.. ~ . ~, ,.
tS~53~
can contain, in addition to ak Ieast one nitrogen atom, other hetero atoms
such as oxygen or sulphur. 5-Membered and 6-membered heterocyclic rings are
preferred. ~xamples of such rings are aziridinoJ azetidino, pyrrolidino,
pyrrolo, imida~olidino, pyrazolino, thiazolino, thiazolidino, piperidino,
morpholino and azepino.
Among "physiologically acceptable acid addition salts'' are
salts of compounds of formula I with suitable organic or inorganic acids such
as hydrochlorides, hydrobromides, sulphates, bisulphates, phosphates, ace
tates, lactates, oleates 9 nitrates, mesylates, tosylates, citrates, maleates,
succinates, tartrates, etc.
According to the process provided by the presen~ invention,
the adenosine nitrates aforesaid (i.e. the compounds of formula I and their
physiologically acceptable acid addition salts) are manufactured by nitrating
- a compound of the general formula NH2
(II)
H~
OH OH
wherein R5 has the significance given earlier, and, if desired, converting
the product into a physiologically acceptable acid addition salt.
`~ The nitration of a compound of formula II can be carried out
according to methods known ~ se.
Thus, the nitration can be carried out, for example, using
nitric acid. Hydrolysis ~by water ~ormed in the reaction) or deamination (by
nitrous acid which may be present) is expediently suppressed by the addition
of a water-binding agent such as concentrated sulphuric acid, oleum, phosphor-
us pentoxide, acetic anhydride and/or a nitrite acceptor such as urea.
. -2-
'"'''''
~6~SlD~i3~
The nitration is expediently carried out at low temperatures,
preferably at -30C. to 25C. and especially at -10C. to 0C.
Thcre are usually obtained mixtures of the 2'-0-nitro,3'-0-
nitro and 2',3'-di-0-nitro compounds in question, which mixtures can be
separated according to generally known methods (e.g. chromatography) and
worked-up to give the pure compounds. It is, however, also possible to con-
trol the process so that the 2~,3'-di-0-nitro compounds are isolated as the
sole products, which is predominantly the case when the aforementioned water-
binding agents are used.
The conversion of the compounds of formula I in~o physiolo-
gically acceptable acid addition salts as well as the formation of such salts
rom addition salts which are not physiologically acceptable can be carried
out in the usual manner.
The compounds of formula I and their physiologically accept-
able acid addition salts possess valuable effects on the heart and on the
circulatory-dynamics and can accordingly be used as medicaments, inter alia,
for the treatment of angina pectoris or essential hypertonia. As dosage
guidelines, an amount of 0.010-30 mg/kg body weight per day can be considered.
Such dosage can be administered not only as a single dose but preferably
several times daily ir divided doses.
-
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53~
The coronary-dilating activity can be measured according
to the following method:
Mongrels weighing between 20 and 38 kg are used for the
examlnations. The test animals are narcotised with ca 30
mg/kg l.v. pentobarbital. The narcosis is maintained wlth
chloralose-ureth~le. The animals are artificially respired
with room-air. After opening the thorax, the hear~ is
exposed and a previously calibrated flow probe of an electro
magnetic flow-meter i5 placed around the Ramus circumflexus of
the left coronary artery to measure the amount of blood
flowlng through. The arterial blood pressure is measured via
a catheter in the Artexla femoralls with a pressure transducer.
Further, a calibrated extensible measuring strip is sutured on
to the surface of the left v~ntricle for the direct measurement
of myocardial contraction force. The pulse wave of the blood
pressure triggers a tachograph for the measurement of the
heart rate. The compounds are dissolved in propyleneglycol
and administered either intravenously or intraduodenally as a
suspension in gum arabic. The maximum action of a substance
i~;calculated in per c~nt of the starting value according to
each do~age. In the measurement of the coronary blood flow,
~peclal attention is paid to the duration o~ actlon.
The results obtained are compiled in the following Table
in which n signifies the number of animals used.
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~ ~ ~9 _~
E4 I-J
C~ ~D ~r ~ u~
~ n er ~1 _I
~ + ++ +
~ /~ .
~1 N __ _
E3 ~ N N O ~ :
~i OD ~ O
. .+ + +
_ __ . __ __ . . .
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,` ~'1~q~
~ ~e u~ ~r ~ co
E~ ~ l ll l
____ __
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, ~ O 00 C~
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~a ~ ~ . a) '.
~`I ~Y ~ ::~
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:, ~ ~ ! !
.~ o~ ~ ~_, o ~ ~ .
. ~ ~a ~ ~ ~ ~ ~U ;' `.'. '
,~ a) ~ ~
~ o ~ o ~ o
O ~ ~rl ~-rl.,
~rl U ~ U ~ U
rl ~ ~ ~ ~~ ~ ~ o
I ~ .
U rl 0 O U O U~ 0 U
~ $ o ~ æ' ~
~ u 0 o~ ~ o~ ~
~! ~ ! ~ ~ ! ~
~ ~n a) ~ u ~ ~ u
., ~ _ _ : ~
.
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. . . . . ` . . - . . .; . . .. . .. ..
5a~i34
The adenosine nitrates provided by the present invention
can be used as medicaments in the form of pharmaceutical
preparations, having direct or delayed release of ~he active
ingredient, which contain them in association with a compatible
pharmaceutical carrier material. This carrier material can
be an organic or inorganlc inert carrier material suitable for
enteral, percutaneous or parenteral administration sueh as,
for example, water, gelatin, gum arabic, lactose, starch,
magnssium stearate, talc, vegetable oils, polyalkyleneglycols,
10 petroleum jelly etc. The pharmaceutical preparation~ can be
! made up ln a solid form (e.g. as tablets, dragées, supposit-
orie~ or capsules), in a 3emi-solid form (e.g. as salves) or
in a liquid form (e.g. as ~olutlons, suspensions or emulslons).
The pharmaceutical preparations may be sterilised and~or may
contain adjuvants such as preservatives, stabilisers, wetting
agents, emulsifiers, flavour-improving agents, salts for
varying the osmotic pressure or buffers. The pharmaceutical
preparations can be prepared ln a manner known per se.
:~;
The 3tarting material~ of formula II hereinbeore are
known or can be prepared from known compounds in a manner known
per ~e.
.. ~
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.
~ID5~53~
The following Examples illustrate the process provided
by the present inventlon:
6.7 g of urea were slowly added at -15C to 90 ml of
fumlng nitric acid (d - 1.5) at such a rate that the temperature
~ dld not exceed ~10Cr To thl~ solution there were added
successively at -10C 10.8 g of adenosine-5'-carboxylic acid
ethyl ester. The solutlon was stirred for 3 hours in an ice-
~ath, introduced lnto a mixture of 225 g of potassium ~lcar-
bonate a~d 1000 g of ice-water and the precipitated crude
product ~4.4. g) was flltered off under suction. By
extraction of the filtrate wlth chloroform/methanol (95:5),
there were obtained a urther 4.4 g of the crude product which,
by chromatography on silica gel wit~h chloroform/ethyl acetate/
methanol (45:45:10), yielded the following nltroadenosines:
2.65 g of 2~,3'-dl-0-nitroade.nosine-5'-carboxylic acid
~ ethyl ester of melting point greater than 135C (decomposition)
: ~rom ethyl acetate/chloroform);
0.41 g of 2~-nitroadenosine-5'-carboxy}ic acid ethyl
ester of meltlng point 170-171C (decompositlon) (from ethyl
acetatejdiethyl ether~; .
1.3 g of 3'-0-nitroadenosine-5'-carboxylic acid ethyl ~-
ester of melting point 166.5-167C (decomposition) (from
ethanol). ~ .
~
.' .
100 ml of fuming nitric acid (d = 1.50) were cautiously
'~:
t~ -
.; ~ . .
353~fl~
treated at -20C with 6.7 g of urea. 10.8 g of adenosine-5'-
ethylamide were dissolved in this solution, the temperature
being maintained at -20C. The mixture was subsequently
stirred firstly at -20C, then slowly warmed to -5C and, after
a total of 5 hours, introduced slowly into excess aqueous
potassium bicarbonate solution ~230 g of potassium bicarbonate
in 800 ml of wate,r). After filtering under suction and
washing the precipitate with water, the filtrate wa~ extracted
five times, each time with 400 ml of a mixture, of ethyl
; 10 acetate and 5% tetrahydrofuran. The organic phases were
washed with saturated sodium ~-hlorLde solution, dried over
magnesium sulphate and concentratefd under reduced pressure.
The total yield of crude product amounted to 11.5 g.
.
In order to separate the crude product into the 3 nitrate
e~ters, it wa~ re,cry~tallised sev~sral times from ethanol, there
being obtained pure 3'-0-nitroadenosin-5'-ethylamlde. 2',3'-
Di-0-nitroadenosin-S'-e~hylamide could be obtained from the
.~ mother }iquors by crystallisation from acetonitrile, while the
complete separation of the mother liquors by chromatography on
silica gel with chloroform/methanol/glacial acetlc acid (90:10~
v/v) alfo ylelded 2'-0-nitroadenosin~e,-57-carboxylic acid ethyl-
am,lde.
. Th~ total yields were:
` 3.0 g (24~) of 3'-0-nitroadenosine-5'-carboxylic acid
ethylamide of melting point 210C (decomposition) (from
i ethanol); -
2.5 g (17.8%) of 2',3'-dl~0-nitroadenosine-5'-carboxylic
acid ethylamide of melting polnt 1~4C (decompo~ition) (from
ace,tonitrile) and
,, ~,,' ~
53~
0.77 g (6.2%) of 2'-0-nitroadenosine-5'-carboxylic acid
ethylamide of melting point 208C (decomposition) (rom
e~hanol).
Example 3
72 ml of fuming nitxic acid were cautiously treated at
~200r with 4.9 g of urea. 6.9 g of adenosine-5'-carboxylic
acid amide were slowly introduced into this solutlon, care
b~lng taken that the temperature of the mixture dld not rise
above -15C. The mixture was stirred for a further 5 hours
while cooling to at lea~t -5C and then slowly added dropwise
into ~xcess aqueous potassium bicarbonate solution (175 g of
potas~ium bicarbonate in 500 ml of water), whereby a portion
of the product precipltated. After filtering under suction
and wa~hing with water, there were obtained 2.9 g of a mixture
of 2',3'-di-0-ni~roadeno31ne-5'-carboxylic acid amlde and 3'- ~ ~
~` 0-nitroadenosine-5'-carboxylic acid amide. ~ The aqueous `
solution was extracted three times with i50 ml of chloroform
a~d 5~ ethanol each tima and ~ubsequently three tlmes with
150 ml of ethyl acetate and 5~ tetrahydrofuran each tlme.
After washing with saturated sodium chloride solution and
drying over magnesium sulphate, there were obtained, after
concentra~ion of the chloroform~ethanol ex~ract, 2.0 g of ;~-
a}most pure 2',3'-dioO-nltroadenosine-5'-carboxylic acid amide
and, ~rom the ethyl acetate/tetrahydrofuran extract, 5.7 g of
a m~xture of 3'-0-nitroadenosine-5'-carboxylic acid amide and
2'-0-nitroadenosine S'-carboxylic acid amlde. Repeated
recrystallisation of the resldue obtained from the chloroform/
ethanol ext~act gave 1.17 g (12.8~) of pure 2',3'-di-0-nitro-
, ,' ` .
,:
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.
'
3~
adenosine~5'-carboxylic acid amide of meltlng point 172.5C
(decomposition). Repeated recrystallisation of the residue
obtained from the ethyl acetate/~etrahydrofuran extract from
ethanol/isopropanol and subsequently from methanol/water gave
2.25 g (28.1%) of 3'-0-nitroadenoslne-5'-carboxylic acid amide
of melting po$nt 211C ~decomposition).
'
xample 4
6.16 g of adenosine-S'-carboxylic acid dimethylamide were
disf~olved at -40C in 60 ml of fuming nitr~c acid (d = 1.50).
A mixturet cooled to -20C, of 30 ml of oleum and 30 ml of
nitromethane was added dropwise to this solution within 30
¦ mlnute~ at such a rate that the temperature did not rise above
i -30C. The mixture was ~tirred for 45 minutes at a temperature
;, between -30C and -25C and then poured on to a solution of
325 g of potassium bicarbonate in 1 litre of water. ~y
extraction with chloroform or with chloroform contalning 5%
n propanol, there was obtained practically pure 2',3'-di-0-
nltxoadenoslne-5'-carboxylic acid dimethylamide which melted
at 156 5C (deoomposition) after recrysta~lisation from alcohol.
The yield was 5078 g (7~.7% of theory).
.
In an analogous manner, the followLng 2',3'-di-0-nitro-
adenosines were obtained:
2',3'~di-0-nitroadenosine-SI-carboxylic acid isopropyl-
amide of melting point 183C (decomposi~ion), yield 77.4%;
2',3'-di-0-nitroadenosine-5'-carboxylic acid cyclo-
hexylamide of melting point 168C (decomposition), yleld G9.5%;
f 2',3'-di-0-nitroadenosine-5'-carboxylic acid ~2-(dimethyl-
amino) ethyl~-amide of melting point 169C (decomposit~on)
,
.'~ ,:', 1 '
534
yield 63%j
2',3'-di-0-nitroad~nosi~e-5'-carboxylic acid [2-(2,4-
dinitrophenyl~-ethyl]-amide of melting point 134C (decom
position), yield 30.6%;
2',3'-di-0-nitroadenoslne-5' carboxylic acid piperidide
of melting point 160C (decomposition), yield 76.2~;
2',3'-di-O~nitroadenosine-5'-carboxylic acid [2-(nitro-
oxy)-ethyl]-amide of melting point 164C (decomposition),
~ yield 58.9%;
:. 10 2',3'-di-0-nitroadenosine-5'-carboxylic acid isopropyl
ester of melting point 158C (decomposition), yield 71.6%.
Example 5
The reaction of 6.16 g of adenosine-5'-carboxylic acid
dlmethylamide with 60 ml of fuming nitric acid and working-up
in the manner descrlbed in ExampIe 4, but without the addition
:o~ oleum/nitromethane t yielded a mixture o 3'-0-nitroadenosine-
;. S?-carboxylic acid dimethylamide of melting point 214C (decom-
po~ition), yield ~1~ of theo~y, with 2'l3'-di-0-nitroadenosine-
S'-carboxylla acid dimethylamide of meltlng point 156C
. 20 (decomposi~lo~), yield 9.3% of theory.
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