Note: Descriptions are shown in the official language in which they were submitted.
1060441
This invention relates to N-(S-tetrazolyl)-pyrimido~1,2-a]quinoline-
2-carboxamides and derivatives thereof and to their use as antiallergy agents.
More particularly, it relates to N-tetrazolyl-l-oxo-lH-6-(R3-substituted)-
pyrimido[l,2-a~quinoline-2-carboxamides wherein the 6-substituent is chloro,
S bromo or lower alkoxy; pharmaceutically-acceptable ca*ionic salts thereof; and
derivatives of such compounds wherein the benzenoid ring bears one or more sub-
stituents, which are useful as agents for the treatment of allergic reactions,
and especially of allergic bronchial asthma; a~d intermediates therefor.
: ~ :
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,
:
1060441
Allergic reactions, the symptoms resulting from an anti~en-Pntibody
intera~ction, manifest themselves in a wide variety~of ways and in dif-erent
organs and tissues. Common allergic disorders, for example, are allergic
rhinitis, a condition characterized by seasonal or perennial sneezing, running
nose, nasal congestion, with itching and congestion of eyes; hay fever, a
variety of allergic rhinitis that results from hypersensitivity to grass pol-
lens; and bronchial asthma, one of the most disabling and debilitating of
l allergic reactions, a disease characterized by hyper-reactivity of the bronchi `
j on exposure to various immunogenic or nonimmunogenic stimuli, resulting in
. ~ bronchospasms with wheez~ng, short-lived paroxysms and widespread constriction
of airway passages. The mechanical obstruction to airflow in airways is gener-
ally reversed by the use of bronchodilators, which provide symptomatic relief.
In contrast, antiallergy agents prevent the release of mediators of anaphylaxis,
¦ rom ti~ue stores, thereby acting in a prophylactic manner to preclude elici-
I tation of bronchoconfitriction by the mediators.
f ¦ Efforts to discover medicinal agents to alleviate the symptoms of
the abnormal physiologic state have been extensive. As early as 1910, Mat~hews~
¦ Brit. Med. J., 1, 441 (1910) reported the bronchodilator effects of epinephrine.
Since then, Chen and Schmidt, J. Pharmacol. Exper. Therap., 24, 339 (1924
;;~; reported the use of the alkaloid ephedrine as an orally efficacious broncho-
dilator wlth the same spectrum of activity as epinephrine. In 1940, Kon~ett,
Arch. ~ . Path. Pharmak., 197, 27 (1940) outlined the effects of the potent
aerosol bronchodilator isoproterenol. Cullum et al., Brit. J. Pharmacol. Ex ."
; 25 35, 141 (1969) reported the pharmacology of salbutamol, a potent bronchodilator
of prolonged duration, and active via both oral and aerosol administration.
~ ; ~any bronchodilator preparations contain theophylline. These are generally
i less potent than the sympathomimetic amines such as isoproterenol and salbuta-
~ ~ol, and are in ffectlve Ln aerosol ad=ini~tration. I
,~
...,. ~ . .. ... ,. ~..... ... ..... .. . ... . . ...... ......
1060441
Recen'ly, Cox and co-workers, Adv. in Drug Res., ~ 115 ~1970), des-
cribed the pharmacology of one such agent, disodium cromoglycate [1,3-bis(2-
carboxycromon-5-yloxy)~2-hydroxypropane, Intal,l~Intall~ is a trademarkO It is
not a bronchodilator, but mediates its therapeutic effects by a unique mechan-
ism of action involving inhibition of release of mediators of anaphylaxis andis administered prophylactically. It suffers from lack of oral efficacy and,
for optimum results, is administered by inhalation as a solid inhalant. Further,
although it is effective against anaphylaxis due to immunog~ubulin E ~IgE), it
is effective against anaphylaxis due to immunoglobulin G ~IgE) only at high
doses C60-70% protection at 100 and 300 mg./kg.).
Although the aforementioned agents represent outstanding contribu-
tions toward the treatment of asthma, many of them exert the undesired side
effect of cardiac stimulation.
The synthesis of a lH-pyrimido~1,2-a]quinoline appears to have first
been reported by Antaki et al., J. Chem. Soc., pages 551-555 ~1951), who con-
densed 2-chloroquinoline with ethyl B-amino c~otonate in the presence of anhy-
drous potassium carbonate and a trace of copper bronze to produce 1-oxo-lH-3-
methylpyrimidoC1,2-a]quinoline. No utility for the compound was reported.
Antaki, J. Am.~Chem. Soc.~ 80, 3066-9 ~1958) reports the condensa-
tion of 2-aminoquinoline and ethylethoxymethylenecyanoacetate to give ethyl 2-
quinolylaminomethylenecyanoacetate which when distilled under reduced pressure
afforded 1-oxo-lH-pyrimido[1,2-a]quinoline-2-carbonitrile. The compound
demonstrated antischistosomal action.
Richardson, et al., J. Med. Chem., ~ 1203-6 ¢1972) describe ethyl
1-oxo-lH-pyrimido~1,2-a]quinoline-2-carboxylate and report it to be inactive
as an antimicrobial agent. When tested for antiallergy activity by the PCA
test lt was found to exhibit 100% inhibition at 3 mg./kg. by the intravenous
(I.V.) route of adm~nistration but is without activity at 1 mg./ke. I.V.
-3-
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.. . .... . .... . . . . .
1060441
Approximately 90~ inhibition is demonstrated at 30 mg./kg. by the oral route
of administration, but oral activity is absent at a dosage level of lO mg./kg.
via the oral route.
It has now been found that compounds having the formula
R ~3
R2~$
N N
0 = ~ - NH~
are valuable antiallergy agents; that is, agents-which inbibit the release of
mediators of anaphylaxis, in mammals, including man, and in this way preclude
elicitation of bronchoconstriction by the mediators. They are not bronchodila-
tors. They are, in contrast to disodium cromoglycate, of practical value
against both IgG and IgE mediated anaphylaxis via the oral, intranasal and
intraperitoneal routes of administration, and by inhalation. In this formula,
each of the benzenoid substituents and Rl and R2 is selected from the group
consisting of hydrogen, lower alkyl, lower alkoxy, fluoro and chloro;
Rl and R2 when taken together are alkylenedioxy of 1 to 2 carbon
atoms and are selected from the group consisting of methylenedioxy and
ethylenedioxy;
R3 is selected from the group consisting of chloro, bromo and lower
alkoxy;
and the pharmaceutically-acceptable cationic salts thereof.
The terms "lower alkyl" and "lower alkoxy" as used herein are intend-
ed to refer to alkyl and alkoxy groups having from one to five carbon atoms
since the reactants necessary to prepare such compounds are more readily
,
available than are those having larger alkyl or alkoxy groups.
-4-
:~:
:: ~
,
:
1~60441
By the term ~pharmaceutically-acceptable cationic saltsl~ is intended
salts such as the alkali metal salts, e.g., sodium and potassium; alkaline
earth metal salts such as calcium and magnesium; aluminum salts; ammonium
salts; and salts with organic bases, e.g., amines such as triethylamine, tri-
n-butylamine, piperidine, triethanolamine ? diethylaminoethylamine, N,N'-di-
benzylethylenediamine and pyrrolidine.
The 5-substituted tetrazoles, as is known, can exist in two isomeric
forms, viz:
N _ ~ ~N _ N
l H
which co-exist in a dynamic tautomeric, equilibrium mixtureO Both forms o~
the tetrazolyl amides are included within the scope of this invention~
The compound6 described herein exhibit a significantly broader
spectrum of anti-allergy activity than do the corresponding acids and e6ters.
Their anti-aller W activity is indeed surprising since the corresponding sim-
ple amides ~e.g., -CONH2, _coN(c2Hs)2~ are inactive as antiallergy agents when
te8ted by the methods do~¢ribed below.
Compounds of particular interest to thi6 in~ention are those wherein
R3 is methoxy or ethoxy and the benzenoid variables (Rl, R2) are hydrogen and
those wherein R3 is methoxy and at least one of the benzenoid substituents is
lower alkoxy Dr ~luoro, the remaining benzenoid substituent being hydrogen.
Rl R2 R3
H H OCH3, OC2H5
H CH3 OcH3~ C2H5
H OC~3 OCH3
H C2H5 OCH3
; H F OCH3
"~
`` 1060441
The antiallergy property of the compounds of this invention is
evaluated by the passive cutaneous anaphylaxis (PCA) test (Ovary, J. Immun.,
81, 355, 1958). In the PCA test, normal animals are injected intradermally
(i.d.) with antibodies contained in serum obtained from actively sensitized
S animals. The animals are then challenged intravenously with antigen mixed
with a dye such as Evans' Blue. The increased capillary permeability caused
by the antigen-antibody reaction causes the dye to leak from the site of the
antibody injection. The test animals are then asphyxiated and the intensity of
the reaction determined by measuring the diameter and intensity of the blue
coloration on the inner surface of the animals' skin.
According to the present invention there is provided a process for
preparing such N-(5-tetrazolyl)-pyrimido~1,2-a]quinoline-2-carboxamides by
dehydrative coupling of the appropriate l-oxo-lH-6-(R3-substituted)pyrimido
[1,2-a]-quinoline-2-carboxylic acid with S-aminotetrazole. The dehydrative
coùpling is accomplished by means of a wide variety of agents commonly used in
peptide synthe~es. Representative agents include N,N'-carbonyldiimidazole,
N,N~-carbonyl-di-s-triazine, ethoxyacetylene, l,l-dichlorodiethylether,
diphenylketene p-tolylimine, N-hydroxyphthalimide, N-hydroxysuccinimide,
N-hydroxypiperidine, ethylene chlorophosphite, diethyl ethylene pyrophosphite,
N-ethyl-5-phenyliso~azolium-3'-sulfonate, phenylphosphorodi-(l-imidazolate) and
carbodiimides such as dicyclohexylcarbodiimide, 1-cyclohexyl-3-(2-morpholino-
methyl)carbodiimide, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydro-
chloride, l-ethyl-3-(3'-dimethylaminopropyl)carbodiimide hydrochloride and
diethyl cyanamide.
The above-described coupling agents are generally reacted first with
the acid reacta~t and the resulting product then reacted without isolation with
~::
: :
-6-
"
-` 106044~
5-aminotetrazole to afford the desired N-(5-tetrazolyl)-1-oxo-lH-6-(R3-
substituted)pyrimido[l,2-a]quinoline-2-carboxamides. The reaction is carried
out in a reaction-inert solvent system in which the acid reactant need not be
soluble. The only reqirement for the solvent system is that it not enter
into any appreciable reaction with the reactants or products. The variety of
coupling agents which can be used to bring about the dehydrative coupling
allow a widè choice of solvents. Representative solvents are N,N-dimethyl-
formamide, tetrahydrofuran, dioxane, methylene chloride, nitromethane and
acetonitrile.
The reaction of the acid reactant with the coupling agent is conduc-
ted at a temperature of from about 20C. to about 110C. The reactive
intermediate is then reacted with 5-aminotetrazole at from about 20C. to
110C. Each of these steps is advantageously carried out at from about 50C.
to about 100C. since the rate and yield of the reaction are improved.
The molar ratio of acid:coupling agent:5-aminotetrazole is generally
about 1:1:1 to about 1:1.1:1.1. Higher ratios of coupling agent and 5-amino-
tetra~ole can be used but offer no advantages. Excesses of ten mole percent
are satisfactory.
As those skilled in the art will recognize, all reactants can be
added at once rather than in stepwise fashion as described above. However,
prior formation of the reactive intermediate ~acid-coupling agent product)
normally produces better yields of desired N-(5-tetrazolyl)amides.
A favored coupling agent is N,N'-carbonyldiimidazole since it affords
a smooth reaction and reasonable yields of desired product without optimiza-
tion of reaction conditions. When using this coupling agent, N,N-dimethyl-
formamide and a temperature of from 85C. to 100C. are preferred conditions
for reasons mentioned above.
-7-
.
:106~441
The compounds wherein R3 is alkoxy are also conveniently prepared
by the Williamson reaction between the appropriate N-(5-tetrazolyl)-l-oxo-lH-
6-chloro(or bromo)pyrimido[l,2-a]quinoline-2-carboxamide and the appropriate
alkanol as exemplified herein.
The required l-oxo-lH-6-(R3-substituted)pyrimido[1,2-a]quinoline-2-
carboxylic acids are prepared by condensation of the appropriate 2-amino-4-
(R3-substituted)quinoline with the appropriate dialkyl ethoxymethylenemalonate
to produce the corresponding intermediate dialkyl 4-(R3-substituted)-2-quinolyl-aminomethylene malonate which is then cyclized to the desired alkyl l-oxo-lH-
6-(R3-substituted)pyrimido[1,2-a]quinoline-2-carboxylate.
The condensation is carried out by heating a stoichiometric mixture
of the 2-aminoquinoline reactant and the dialkyl ethoxymethylenemalonate at a
temperature of from about 80C. to about 125C. Lower temperatures are not
desirable because the reaction proceeds at too slow a rate. Higher temperatures
lS can be used but appear to offer no advantages. The reaction is thus conveni-
ently carried out as a melt. It can, of course, be conducted in a solvent or
mixture of solvents; for example, ethanol, N,N-dimethylformamide, acetonitrile.
However, from a practical standpoint a solvent appears unnecessa~y.
The intermediate dialkyl 4-(R3-substituted)-2-quinolylaminomethylene-
malonate thus produced is then cyclized, preferably thermally, by heating to a
temperature of from about 175C. to about 250C. in a suitable reaction-inert
~ diluent; that i8, in a compound which permits control of the reaction tempera-
- ture, i8 stable to the relatively high temperatures employed and which does not
react with the starting material or the products of cyclization. Representativeof such diluents are high boiling hydrocarbons such as perhydronapthalene,
mineral oil, diethylbenzene, acetic anhydride contai~ing sulfuric acid, dl-
phenyl ether and diphenyl, especially that which contains 26.5% diphenyl and
73.5% diphenyl ether and is sold as Dowtherm A ("Dowtherm" is a trademark).
,
~ -8-
..... . . ... . ... . ..
1060441
The alkyl l-oxo-lH-6-(R3-substituted)pyrimido[1,2-a]quinoline-2-
carboxylates are converted to the correspond;ng acids by hydrolysis, preferably
acid hydrolysis. The usual conditione comprise heating an aqueous mixture of
the appropriate ester and a m;neral acid such as hydrochloric, sulfuric, phos-
phoric or nitric acids, from about 50C. to about 100C. for periods of up tofour hours or until hydrolysis is essentially complete. The favored mineral
acid is hydrochloric acid of from 3N to 12N concentration. The less soluble
the ester reactant in water, the more concentrated the acid used for hydrolys;s.
The free acids generally crystallize from the hydrolysis reaction mixture upon
cooling and are recovered by filtration. When crystallization does not occur
the acids are recovered by evaporation of the reaction mixture. The acids are
purified by recrystallization from suitable solvents, such as N,N-dimethyl-
formamide.
Salt formation is accomplished by reacting the appropriate acid with
the approprlate metal salt~ such as a carbonate, bicarbonate, acetate, hexano-
ate, hydroxide, ln suitable medium such as water, methanol or ethanol according
to well-known procedures, The salts are recovered by standard methods such as
by filtration if they are insoluble in the medium, by evaporation of the sol-
vent if they are soluble in the medium or by precipitation by addition of a
non-solvent for the salt.
As noted above, the N-(5-tetrazolyl)amides of this invention exhibit
a significantly broader spectrum of antiallergy activity than do the precursor
acids. The acids are effective in inhibiting only anaphylactic phenomena
mediated by immunoglobin E (IgE). In contrast, the N-(5-tetrazolyl)amides are
not only effective against reaginic induced anaphylaxis (IgE, immunoglobin E),
but also against immunoglobin G (IgG) ;nduced anaphylaxis. This behavior is
also in contrast to the action of disodium cromoglycate which does not inhibit
IgG-medlated responsçs except at high doses.
_g_
:
~ ~ , . . . . . ~ , . . .
1060441
The products of this invention and the pharmaceutically-acceptable
cationic salts thereof are useful as prophylactic agents to inhibit or prevent
the release of mediators of anaphylaxis (allergy, immediate hypersentitivity
reactions) and the occurrence of allergic symptoms in mammals, and can be
administered for such uses individually or as mixtures with other agents; for
example, with theophylline or sympathomimetic amines. They can be admin;stered
alone, but are generally administered with a pharmaceutical carrier selected on
the basis of the chosen route of administration and standard pharmaceutical
practice. For example, they can be combined with various pharmaceutically
acceptable inert carriers in the form of tablets, capsules, lozenges, troches,
hard candies, powders, aerosol sprays, aqueous suspensions or solutions, injec-
table solutions, elixirs, syrups and the like. Such carriers include solid
diluents or fillers, sterile aqueous media and various non-toxic organic sol-
vents. Moreover, the oral pharmaceutical compositions of this ;nvention can
be suitably sweetened and flavored by means of various agents of the type
commonly used for this purpose.
The particular carrier selected and the proportion of active ingredi-
ent to carrier are influenced by the solubility and chemical nature of the
therapeutic compounds, the chosen route of administration and the needs of
standard pharmaceutical practice. For example, when the compounds of this
invention are administered orally in tablet form, excipients such as lactose,
sodium citrate, calcium carbonate and dicalcium phosphate can be used. Various
disintegrants such as starch, alginic acids and certain complex silicates,
together with lubricating agents such as magnesium stearate, sodium lauryl
sulphate and talc, can also be used in producing tablets for the oral adminis-
tration of these compounds. For oral administration in capsule form, lactose
and high molecular weight polyethylene glycols are among the preferred materi-
als for use as pharmaceutically-acceptable carriers. Where aqueous suspensions
-lQ-
..
1060~41
are to be used for oral administration, the compounds of this invention can be
combined with emulsifying or suspending agents. Diluents such as ethanol,
propylene glycol, glycerine and chloroform and their combinations can be
employed as well as other materials.
For the purpose of parenteral administration and inhalation, solu-
tions or suspensions of these compounds in sesame or peanut oil or aqueous
propylene glycol solutions can be employed, as well as sterile aqueous solutionsof the soluble pharmaceutically-acceptable salts described herein. These par-
ticular solutions are especially suited for instramuscular and subcutaneous
injection purposes should such method of administration be desired. The
aqueous solutions, including those of the salts dissolved in pure distilled
water, are also useful for intravenous injection purposes provided that their
pH is properly adjusted beforehand. Such solutions should also be suitably
buffered, if necessary, and the liquid diluent first rendered isotonic with
sufficient saline or glucose.
The compounds can be administered to asthmatic subjects suffering
from bronchoconst~iction~by means of inhalators or other devices which permit
the active compounds to come -into direct contact with the constricted areas of
the tissues of the subject. When administered by inhalation, the composit;ons
can comprise (1) a solution or suspension of the active ingredient in a liquid
medium of the type mentioned above for administration via a nebulizer; (2) a
suspension or solution of the active ingredient in a liquid propellant such
as dichlorodifluoromethane or chlorotrifluoroethane for administration from a
pressurized container; or (3) a mixture of the active ingredient and a solid
diluent (e.g., lactose) for administration from a powder inhalation device.
Compositioas suLtable for inhalation by means of a conventional nebulizer will
comprise about O.l to about 1% of active ingredient; and those for use in
~ .
" 1060441
pressurized containers will comprise from about 0.5 to about 2% of active
in~redient. Compositions for use as powder inhalants can comprise ratios of
active ingredient to diluent of from about 1:0.5 to about 1:1.5.
It is necessary that the active ingredient form a proportion of the
composition such that a suitable dosage form will be obtained. Obviously,
several dosage unit forms can be administered at about the same time. Although
compositions with less than 0.005% by weight of active ingredient might be
used in certain instances, it is preferred to use compositions containing not
less than 0.005% of the active ingredient; otherwise, the amount of carrier
becomes excessively large. Activity increases with the concentration of the
active ingredient. The CompositiQn may contain 10, 50, 75, 95, or an even
higher percentage by weight of the active ingredient.
As regards the dosage regimen of the compounds of this invention, the
physician will ultimately determine the dosage which will be most suitable for
a particular individual, and it will vary with age, weight and response of the
partlcular patient as well as with the nature and extent of the symptoms, the
pharmacodynamic characteristics of the particular agent to be administered and
the route of administration chosen. Generally, small doses will be administered
initially, with a gradual increase in the dosage untiI optimum level is deter-
23 mined. It will often be found that when the composition ;s administered oral~
ly, larger quantities of the active ingredient will be required to produce the
~ same level as produced by a small quantity administered parenterally.
; - Having full regard for the foregoing factors, it is considered that
an effective daily oral dosage of the compounds of the present invention in
humans of from about 10 to about 1500 mg. per day, with a preferred range of
:
about 10 to about 6~0 mg. per day in single or divided doses, or at about 0.2
to about 12 mg./kg. of body weight will effectively alleviate bronchoconstric-
:, ~
h~ tion in human sub~ects. These values are illustrative and there may, of
; course, be individual cases where higher or lower dose ranges are merited.
-12-
~:::: ~ ' ,
1060441
When administered intravenously or by inhalation, the effective
daily dose is from about 0.5 to about 400 mg. per day, and preferably from
about 0.25 to 200 mg. per day, or at about 0.005 to 4 mg./kg. of body weight
in single or divided doses.
The same two basic changes are present in cases of anaphylactic
shock: (l) ar increase in permeability of capillaries, and (2) concentration of
smooth muscle. The increased capillary permeability is the result of antigen-
antibody interaction. It, and smooth muscle contraction, can be observed and
readily measured. This increase in capillary permeability forms the basis of
the PCA test.
The PCA test is a measure of the anti-allergic (especially anti-
asthmatic) activity of a compound. Compounds which inhibit a positive PCA
test induced by the rat immunochemical counterpart of human immunoglobulin E
(IgE), or reagin, are considered to have anti-allergic activity (C. Mota, Ann.
N,Y, Acad. Sci " 103, 264 (1963) ~Reagln is primarily immunoglobulin E [IgE]
and 1s the prin¢ipal immunoglobulin responsible for allergic asthma, anaphy-
laxis, hay fever, food sensitivities and certain manifestations of drug
sensitivities), Such compounds when administered to a sensitized subject,
human or animal, prior tc the time when the subject comes into contact with
an$igens or substances to which it is allergic, will prevent the allergic
reaction which would ~therwise occur. They, therefore, provide a method for
the prophylactic treatment of allergy or anaphylactic reactions of a reagin
mediated nature.
;- To put it another way, such compounds block the release of mediators
: ~ ,
~ 25 resulting from the antigen-an~ibody ~allergic) reaction as illustrated in the
~ - ~
PCA test using rat homocytotropic antibody--a known correlate of human reaginic
antibody Inhibition of réaginic antigen-an~ibody reac~ions in rats, the test
. ~ ~
'~' ~: : :
; -13-
: '
1060441
animal of the PCA test, is regarded as representative of inhibition of human
reag;nic antigen-antibody reactions which occur during allergic episodes.
The PCA reaction test procedure employed to evaluate the compounds
of the present invention demonstrates an excellent correlation between activity
for compounds in this test and their utility in the treatment of allergic
asthma. The ability of agents to interfere with PCA reactions is measured in
male Charles River Wistar rats, 170-210 g. Reaginic antiserum, rich in IgE
antibodies is prepared according to Petillo et al., Int. Arch. Allergy, 44,
309 (1973). Hyperimmune antiserum rich in IgG antibodies to hen egg albumin is
prepared according to Orange, et al., J. Exptl. Med., 127, 767 (1968). Forty-
e;ght hours prior to antigen challenge, the reaginic antiserum is injected
intradermally (i.d.) into the shaved skin of a normal rat's back; five hours
before challenge the hyperimmume antisera is similarly injected. At a third
site 60 mcg. histamine dihydrochloride and 0.5 mcg. serotonin creatinine sul-
fate are injected i.d. ~ust prior to antigen challenge as a check for anti-
histaminic, antiserotonin and unspecific types of blockage; the compounds of
the instant invention or saline are then administered i.v. and immediately
followed by the challenge of 5 mg. egg albumen and 2.5 mg. Evans's Blue dye in
saline. In the case of oral administration Evans's Blue dye and egg albumen
are given five minutes after administration of the drug. Thirty minutes later
the anim&ls are asphyxiated uslng chloroform and the skin of the back removed
and reversed for observation. A score is assigned each in~ection s~te equal to
the product of the diameter of the site in mm. and a grade of 0.1, 0.5, 1,2,
3 or 4~proportional to intensity of dye coloration. The scores for a given
; 25 in~ection site are summed for each group of 5 animals and compared to the
saline treated controls. The difference i8 expressed as percent blockage due
to the compound employ-d.
-14-
1060441 - . 1
Comyounds representatiye of those of the prèsent invention are'`
i tested for antiallergy activity by the above-describ~d procedure and the
resulting àctivities are reported as the degree (~0~ of protection. Intal,
disodium cromoglycate, a commercial a~tiallergy agen~, is included for
comparison.
The compounds tested are of the formula `
.' ~
1.
,' , I
' ' ,, ,. '.,
.,
~ ' ' . ' . ' 1.' ~ "
,
.
~ : ~ - 15 - ' I
~ ~ ~ ' ' ', I
, : : ~ ~ ' ' ' .
~ , , ,'. ... ,............ I
~ . , , - , , ,
11~60441
,
.
.
_ I ,~ O ~ O~ cn o ,~
2, . . ..
o, ~, ~ o ~ o ~ o ~ o ~ o ~ o
o ~ o ~ o ~ ~o C~ o~ ~ o~ ~ o~
,oooooooo~oooooo
_ I ~ ~ D ~1 00 0 ~ ~ ~ r~ o ~
æ ~1 .
W ~
o ~ o ~ o o~ o ~ o ~ o
. ~ ~1 ~D CO O ~ O ~ ~ ~ o o o~ o ~ ~ co
P I . ~ I~ ~o o oo 1~ ,~ oo
~ 0~ .,
l ~
~-- ~ ~ ~ o ~ o ~ o ~ o ~ o ~ o
~ ~ o o o o o o o o ~ o o ~ o o o o
: . :
~ o o :o o ~ o o ~ o
w s
--
:r: W W :~ W ~ W W
-16- '
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060441 ;
Example I
~-(5-Tetrazolyl)-l-oxo 1~1-6-me~hoxypyrimido~1,2-a]-
_ _______!lUinline-~-carboxamide _
' A mixture of l-oxo-lH~6-methoxypyrimido~1,2-a~quinoline-2-carboxylic
5acid (540 mg., 2,0 mmole) and N,N'-carbonyldiimidazole (357 mg., 2.2 mmole) in
' N,N-dimethylformamide (15 ml.) is stirred and heated on a steam bath for fif-
teen minutes. A clear solution forms after approximately five minutes' heatin~,
followed by formation of'a precipitate. The reaction mixture is stirred an
additional 45 minutes at ambient temperature and is then treated with 5-amino-
tetrazole'(l87 mg., 2.2 mmole). The ~ixture is heated on a steam bath for
forty minutes and is then cooled and filtered to recoYer the product (540 mg.
of yellow solid); m.p. 220 C. (dec.).
It is purified by dissolving in hot N,N-dimethylformamide at the rate
' of 200 ~g. crude product per 20 ml. of solvent, fîltering the hot solution and
then chilling the filtrate. The yellow crystals are filtered and dried;
m.p. 255 C. (dec.) .
Analysi~: Cslc~d for C15H1103N7: C, 53.41; H, 3.29; N, 29.07 %
~ound: C, 53.12; H, 3.67; N, 28.75 %
The following compounds are similarly prepared from appropriate
reactants:
- Rl 13
' ~ N ~
R2 ~ ~ N~N
O~C~
s
-:~ ~: -' ;
- , `
- 16a_
''' ' ' ~' , ,
,
.
`
`, ~
~ ., , ~
1060441
. . . - '.
,~ ~ . ..
, ~ 3
o ~U~ I~ ~ ,, oo ~ `
zi In a~U~ o ~ ~ a~
r~ n
: ~
~1 C~~1 U~ ,~ CO ~ ~ ' '' `'
~ ~ ~O _I C~l
::~ :1~ , . . . .
,0 ~;t~ ~ ~ ~ ~) ~)~)
a~ ~ ~ u,
n ~ ~ ,~ ~ u~
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-" ` 1061)441
The product of Example VIII ;s purified by dissolution in ammonium
hydroxide (6N) from which the product precipitates on standing. The solid is
filtered, dissolved in water and precipitated from solution by acidification
with 3N hydrochloric acid. It is filtered, dried and recrystallized from N,N-
dimethylformamide.
The product of Example IX is purified by recrystallization from N,N-
dimethylformamide, followed by the purification method accorded the product
of Example VIII.
EXAMPLE X
The compounds tabulated are prepared from appropriate reactants by
the procedure of Example I.
Rl
O= -N ~ ~ '`~
H
10~0441
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:
-19-
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1060441
EXAMPLE XI
N-(5-Tetrazolyl)-l-oxo-lH-6-ethoxypyrimido~1,2-a]-
quinoline-2-carboxamide
A mixture of p-toluenesulfonic acid monohydrate (20 mg.) and N-(5-
tetrazolyl)-l-oxo-lH-6-chloropyrimido~1,2-a]quinoline-2-carboxamide (1.79 g.)
irl ethanol (75 ml.) is heated at reflux for 24 hours. The solvent is removed
under reduced pressure and the residue partitioned between 3N hydrcchloric
acid (25 ml.)--ethyl acetate (100 ml.). The phases are separated and the ethyl
acetate phase extracted with 3N hydrochloric acid (2 x 20 ml.). The acid ex-
tracts are combined, made neutral (pH 7-8) with 20% ammonium hydroxide and the
resulting precipitate recovered by ~iltration (235 mg.).
The above procedure is repeated but using the ~-chloro(or bromo)
products of Example X and the appropriate a}kanol to give the compounds
tabulated below:
Rl R3
R2
O~~
~r
H
Rl R2 R3
- H 8-OCH3 OCH3
H 8-OCH3 0-n-C4Hg
8-CH3 10-CH3 OCH3
7-CH3 lO-OCN3 C2H5
N 10-Cl OCH3
H 8-Cl OCH3
:
H 9-Cl O-n-C3H7
8-OCH3 9-OCH3 OC2H5
H H OCH3
-20-
1060441
EXAMPLE XII
Salt Formation
The products of Examples I-XI are converted to the sodium, potassium,
ammonium, calciu~, magnesium, aluminum, triethylamine, tri-n-butylamine,
piperidine, triethanolamine, diethylamino~thylamine, pyr~oiidine and N,N-di-
benzylethylenediamine salts by reaction with an equivalent of the appropriate
metal hydroxide, ammonium hydroxide or amine in water or ethanol followed by
filtration of the salt if it is insoluble or by evaporation of the solvent if
the salt is soluble therein.
EXAMPLE XIII
Injectable Preparation
One hundred grams of N-(5-tetrazolyl)-1-oxo-lH-6-methoxypyrimido-
~1,2-a]qùinoline-2-carboxamide are intimately mixed and ground with ~50 grams
of sodium ascorbate. The ground, dry mixture is placed in vials and steril;zed
with ethylene oxide after which the vials are sterilely stoppered. For intra-
venous administration, sufficient water s added to the materials in the vials
to form a solution containing 5.0 mg. of active ingredient per mill;liter of
in~ectable solution.
1060441
EXAMPLE XIV
Tablets
A tablet base is prepared by blending the following ingredients in
the proportion by weight indicated:
5Sucrose, U.S.P. 80.3
Tapioca Starch 13.2
Nagnesium Stearate 6.5
Into this tablet base there is blended sufficient N-t5-tetrazolyl)-
l-oxo-lH-6-methoxypyrimido~1,2-a]quinoline-2-carboxamide to provide tablets
10containing 20, 100 and 250 mg. of active ingredient per tablet. The composi-
tions are each compressed into tablets, each weighing 360 mg., by conventional
means.
EXANPLE XV
Capsules
15A blend is prepared containing the following ingredients:
Calcium carbonate, U.S.P.17.6
Dicalcium pho8phate 18.8
Magnesium trisilicate, U.S.P. 5.2
Lactose, U.S.P. 5.2
Potato starch 5.2
,
Magnesium stearate A 0,8
Magnesium stearate B 0,35
To this blend is added sufficient N-t5-tetrazolyl)-1-oxo-lH-6,9-
dim-thoxypyrimido[1,2-a]quinoline-2-carboxamide to provide capsules containing
2510, 25, and 50 mg. hard gelatin capeules in the amount of 350 mg. per capsule.
: ~ :
-22-
::
:,
1060441
In like manner, capsules containing 2.0 mg. and 6.0 mg. of active
ingredient, and having 300 mg. of the following blends per capsule are
prepared:
IngredientsWeight mg./capsule
Drug 2.00
N-Methylglucamine18.00
Lactose, anhydrous 241.20
Corn starch, anhydrous 30.00
*Talc 8.80
IngredientsWeight mg./capsule
Drug 6.00
N-Methylglucamine18.00
Lactose, anhydrous 237.20
Corn starch, anhydrous 30.00
*Talc 8.80
*Talc added before encapsulation
EXAMPLE XVI
Solution
A solution of N-(5-tetrazolyl)-1-oxo-lN-6-methoxy-9-fluoropyrimido-
[1,2-a]quinoline-2-carboxamide i8 prepared with the foIlowing composition:
Effective ingredient 6.04 grams
Magnesium chloride hexahydrate 12.36 grams
: ,
; - Monoethanolamine 8.85 ml.
Propylene glycol 376.00 grams
5 25~ Water, distilled 94.00 ml.
The resultant solution has a concentration of effective ingredient of
,: ~ f -
10 mg./ml. and is suitable for parenteral and, especially for intramuscular
administration.
; ~ -23-
,
.
1060441
EXAMPLE XVII
An aqueous solution of N-(5-tetrazolyl)-1-oxo-lH-6-methoxypyrimido-
[1,2-a]quinoline-2-carboxamide sodium salt (containing 3 mg. of drug per ml. of
solution) is placed in a standard nebulizer such as ls ava;lable from the
Vaponephrine Co., Edison, N. J. The solution is sprayed under an air pressure
of 6 lbs. per square inch into a closed 8" x 8" x 12" plastic container for
six minutes. The container has four openings to ~ccommodate-the heads of four
rats. Four rats are exposed to the drug simultaneously with only the;r heads
coming in contact with aerosol. The results are evaluated as per the PCA
reaction test procedure described above.
EXAMPLE XVIII
Aerosol Suspension
A mixture of N-(5-tetrazolyl)-1-oxo-lH-6-methoxypyrimido[1,2-a]-
quinoline-2-carboxamide (antiallergy agent) and the other ingredients under (a)
lS in the examples below are micronized to a particle size of 1 to 5 microns ;n a
ball mill. The resulting slurry is then placed in a container equipped with a
valve and propellant (b) introduced by pressure filling through the valve noz-
le to a gauge pressure of approximately 35-40 pounds per square inch at 20C.
Suspension A Percent
(a) Antiallergy agent 0.25
Isopropyl myristate 0.10
Ethanol 26.40
(b) 60-40% mixture of 1,2-dich,lorotetrafluoro- 73.25
ethane-l-chloropentafluoroethane
Suspension B Percent
(a) Antiallergy agent 0.25
Ethanol 26.50
(b) 60-40% mixture of 1,2-dichlorotetrafluoro- 73.25
ethane-l-chloropentafluoroethane
-24-
1060441
PREPARATION A
Ethyl l-Oxo-lH-6-methoxyprimido~1,2-a]quinoline-2-carboxylate
(1) A mixture of 2-amino-4-methoxyquinoline (34 g., 0.196 mole) and
diethyl ethoxymethylenemalonate (46.8 g., 0.216 mole) is heated on a steam
bath. A clear melt forms within about 10 minutes and within about twenty
minutes begins to resolidify. The mixture is heated a total of 45 minutes
and is then cooled. The product, diethyl 4-methoxy-2-quinolylaminomethylene-
malonate, is crystallized from ethanol (350 ml.) as a fluffy solid; m.p. 136.5-
137.5~C.
Analysis: Calc'd for C18H20N205: C, 62.78; H, 5.85; N, 8.14 %
Found : C,`62.72; H; 6.10, N, 8.37 %(2) To Dowtherm A ("Dowtherm" is a trademark) (350 ml.) at 100C. is
added the product from (1) (55 g., 0.16 mole) and the resulting clear yellow
solution heated to 230-233C. for 1.75 hours. The reaction mixture is cooled,
diluted with ethyl acetate (500 ml.) and then extracted with lN hydrochloric
a¢id ~3 x 120 ml.~. The extracts are combined, made basic with 20% ammonium
hydroxide and chilled to precipitate the product. It i8 filtered and recrystal-
lized successively from ethanol, benzene - cyclohexane (1:1) and ethanol to give
15.5 g. of yellow crystals; m.p. 130-130.5C.
(3) Alternatively, the procedure of Preparation A(2) is repeated but
starting with 3.5 g. of diethyl 4-methoxy-2-quinolylaminomethylenemalonate.
The product is recovered by cooling the reaction mixture, diluting it with
cyclohexane (150 ml.) to precipitate the crude product as a brown gummy materi-
al. It is obtained in crystalline form by heating the diluted reaction mix-
ture to boiling and filtering the hot mixture. Upon cooling the product pre-
cipitates as yellow crystals and is separated by filtration. Yield = 1.1 g.
Further purification is achieved by recrystallizing it from ethanol.
-25-
..... . . ~ ~ . . .
- .. - - .. ..
1060441
PREPARATION B
Following the procedures of Preparation A(l) and A(3), the compounds
listed below are prepared from appropriate reactants. In most instances, the
product separates in the form of crystals upon dilution of the reaction mixture
with cyclohexane and hot filtration of the mixture is unnecessary.
. The following are thus prepared:
IR3
1 ~1
11 1
2 ~ I
d`~
OOC2H5
~3 ~1 R2 m.p. (C.)
OCH3 Cl H 213-214
OCH3 CH3 H 191.5-192.5
OCH3 OCH3 H 200-201.5
OCH3 H OCH3 184-185
OCH3 H C1 178-179
OCH3 H CH3 139-141
OCH3 OCH3 OCH3 215-216
OCH3 OC2H5 H 163.5-164.5
OC2H5 H H 143-145
: OCH3 H F 141-143
OCH3 F H 175.5-177
.
-26-
.. . .. ,. . . - - - .
-`-` 1060441
PREPARATION C
l-Oxo-lH-6-methoxypyrimido[1,2-a]quinoline-2-carboxylic Acid
A mixture of ethyl l-oxo-lH-6-methoxypyrimido[1,2-a]quinoline-2-
carboxylate (3.0 g.) and concentrated hydrochloric acid (60 ml.) is heated on
a steam bath for a half hour. It is then cooled and filtered to give 0.87 g.
of the title product. It is recrystallized from N,N-dimethylformamide; m.p.
219~C. (dec.).
In like manner, the products of Preparation B are hydrolyzed to the
corresponding acids.
IR3
- ~ih
2 ~ N
00H
R3 Rl R2 m.p. (C.)
OCH3 Cl H 239 (dec.)
OCH3 CH3 H 247 (dec.)
OCH3 OCH3 H
OCH3 H OCH3 230 (dec.)
OCH3 H C1 234 (dec.)
OCH3 H CH3
OCH3 OCH3 OCH3 245 (dec.)
OCH3 OC2H5 H 237 (dec.)
C2HS H H 205 (dec.)
OCH3 H F 196-198 (dec.)
OCH3 F H 265-268 (dec.)
-27-
1060441
PREPARATION D
(1) A mixture of 2-amino-4-chloroqui~oline ¢15.5 g~, 0~087 mole) and
diethyl ethoxymethylenemalonate (20.8 g., 0.096 mole) i6 heated on a steam
bath for 45 minutes, Isopropanol ¢75 ml.) i8 added to the hot clear melt
which is then cooled. The product separates and ;s filtered, washed with
isopropanol and dried. Yield = 26.0 g. of white solid; m.p. 108.5-109.5C.
It ls used directly in step ~2) without further purification.
Recrystallization from ethanol affords an analytical sample, m,p.
109-110C.
(2) The intermediate diethyl 4-chloro-2-quinolylaminomethylenemalonate
from step ~ 26 g.) is added to Dowtherm A C~IDowtherml~ is a trademark) ¢75
ml.) at 100C. The resulting clear solution is heated to 235-237C. for 80
minutes and then cooled. Hexane ~100 ml.) is added to the reaction mixture
and the product which precipitates recovered by filtration, washed with
hexane and dried. It is recrystallized from acetonitrile, m.p. 178-179C.
The following compounds are prepared from appropriate reactants
by the procedures of Preparation D CR3 = Cl, Br) and A(l) and A~3) (R3 =
alkoxy and Cs R3
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' 1060441
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