Note: Descriptions are shown in the official language in which they were submitted.
r
--1--
P.C. 6078
Novel Aminothiazoles
This invention relates to novel substituted
aminothia~oles useful for relieving inflammatory
conditions and as immune regulants.
A number of compounds have been know~ in the art
to be useful as anti-inflammatory agents, for example
the cortico steroids; phenylbutazone, indomethacin and
various 3,4-dihydro-4-oxo-2H-1,2-benzothiazine-4-
carboxamide-l,l-dioxides, such as those disclos~d in
10 United States Patent No. 3,591,5~4. Accordingly,
these compounds have been of therapeutic value in the
treatment of arthritic and other inflammatory conditivns
such as rhPumatoid arthritis. Such conditions have
also been treated by administration of immunoregulatory
15 agents, such as levamisole, as described for example in
Arthritis Rheumatism, 20~ 1445 (19773 and Lancet, 1,
393 (1976). In efforts to find new and improved
therapeutic agents for the treatment of these conditions,
it has now been found that the novel aminothiazoles
20 of the present invention have a particularly desirable
combination of pharmacological properties, namely that
they are active both as anti-inflammatory agents and
as regulants of the immune response in the body.
Accordingly, they are of particular value in the
25 treatment of rheumatoid arthritis and other conditions
where relief of the inflammation and regulation of the
body immune response is desired.
The synthesis of a limited number of 2-aralkyl-
aminothiazoles has been described in the art, for
example 2-phenethylaminothiazole, Chem. Abs. 59, 1613e
(1963); 2-benzylaminothiazole, J.A.C~S., 74, 2272 (1952)
.. ~
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,
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:: ., .
949
and 2-benzylamino-4-phenyl-thiazole, J. Ind. Chem. Soc., 4~, 57 (1967).
These articles do not, however, disclose any pharmacological activity of
such compounds.
This invention relates to substituted aminothiazoles useful as
anit-inflammatory agents and as regulants of the body immune response. More
particularly, the novel compounds of this invention are those of the formula
R ~ N
~ ~ NH-Rl
S
and the pharmaceutically acceptable acid addition salts thereof, wherein R
is selected from -CH~ , -(CH2)2-X, -CH2-CH2-NH-X and -(CH2) Y, wherein X
is selected from phenyl and monosubstituted phenyl, said substituent being
selected from alkyl of 1 to 3 carbon atoms, hydroxy, alkoxy of 1 to 3 carbon
atoms, chloro, bromo and fluoro; Y is selected from thienyl, monosubstituted
thienyl, furyl and monosubstituted furyl, said substituent being selected
from alkyl of 1 to 3 carbon atoms, chloro, bromo and fluoro; m is an integer
from 1 to 2; R2 is selected from phenyl, thienyl and monosubstituted phenyl,
said substituent being selected from alkyl of 1 to 3 carbon atoms, hydroxy,
alkoxy of 1 to 3 carbon atoms, chloro, bromo and fluoro; and R3 is selected
from hydrogen, alkyl of 1 to 3 carbon atoms, phenyl and monosubstituted
phenyl, said substituent being selected from alkyl of 1 to 3 carbon atoms,
alkoxy of 1 to 3 carbon atoms, chloro, bromo, and fluoro. Preferred substit-
uents for R2 are phenyl and p-fluorophenyl and for R3 are hydrogen and
phenyl.
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79~
A preferred group of compounds is that wherein Rl is -(C112)-X.
Most preferred are those compounds where X is phenyl or p-methoxy phenyl,
R2 is phenyl or p-fluorophenyl, R3 is phenyl, methyl or hydrogen, including
2-phenethylamino-4-phenyl-thiazole, 2-phenethylamino-4,5-diphenylthiazole
and 2-phenethylamino-5-methyl-4-phsnyl-thiazole.
A further group of interest is that wherein Rl is -(CH2)m-Y, espe-
cially where m is 1. Preferred groups for Y are thienyl and furyl, espe-
cially those compounds where R2 is phenyl or p-fluorophenyl and R3 is hydro-
gen, methyl and phenyl.
Yet a further group of compounds are those wherein Rl is -CH ~ ,
preferred compounds being those where X is phenyl, R2 is phenyl and R3 is
hydrogen or phenyl.
Another group of compounds of interest are those wherein Rl is
-CH2-CH2-NH-X, especially those compounds where X is phenyl, R2 is phenyl
and R3 is hydrogen.
Also embraced by the present invention are pharmaceutical composi-
tions comprising a novel substituted aminothiazole of this invention, as de-
scribed above herein, or a pharmaceutically acceptable acid addition salt
thereof, together with a pharmaceutically acceptable carrier or diluent.
Preferred pharmaceutical compositions are those containing the preferred
compounds described above and most preferably containing 2-phenethylamino-
4-phenyl-thiazole, 2-thenylamino-4-~p-fluorophenyl)-thiazole or 2-(p-meth-
oxyphenethylamino)-4-(p-fluorophenyl)-thiazole or pharmaceutically accept-
able acid addition salts of these compounds.
Also claimed is a method of treating rheumatoid arthritis in a
host which comprises administering to said host an effective anti-arthritic
amount of a novel aminothiazole of this invention, especially those pre-
ferred compounds described above and most preferably 2-phenethylamino-4-
-- 3 --
.
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phenyl-thiazole, 2-(p-methoxyphenethylamino)-4-(p-fluorophenyl)-thiazole or
2-thenylamino-4-(p-fluorophenyl)-thiazole or pharmaceutically acceptable
acid addition salts thereof.
The novel aminothiazoles of this invention are prepared from an
appropriately substituted N-aryl thiourea of the formula RlNHCNH2, where R
is as previously defined. The latter compounds are readily prepared from
known and readily available amines of the formula RlNH2. For example~ when
the group Rl is -~CH2)2-~, unsubstituted or appropriately substituted phen-
ethylamines are employed. Corresponding thenyl or furyl analogs of these
amines will be used to prepare compounds where Rl is -~CH2)m-Y. Where Rl
is -CH , unsubstituted or substituted diphenylmethylamines are approp-
riate starting materials, while when Rl is -CH2-CH2-NII-X, unsubstituted or
substituted n-phenethylenediamines are employed. In the above, X, Y, n and
m are as previously defined. The amine starting material is first converted
to the hydrochloride or other hydrohalide salt by reaction with hydrogen
chloride or other hydrogen halide, generally by bubbling the gas into a so-
lution of the amine in an inert organic solvent, typically an ether such as
diethyl ether, at a temperature of about -10C to about 10C. The amine
hydrohalide salt is then reacted with ammonium thiocyanate or an alkali
metal thiocyanate, such as potassium thiocyanate, in an inert organic sol-
vent, generally an aromatic solvent such as bromobenzene,
chlorobenzene, xylene and the like, to form the desired
N-aralkyl thiourea. The reaction is preferably conducted in an
inert atmosphere, for example under nitrogen, at a temperature of about
110C to about 250C, preferably 150C to 200C, for example at the
:
: - .. . : : ::, ~ , :
:
. . :: .
:. . . : ~
.. . . .
reflux temperature in bromobenzene. The reaction will
generally be complete in about 30 minutes to about 6
hours depending on the temperature employed, generally
in about l to 3 hours at 150 ~o 200C. In preparing
the N-aralkyl thioureas as described above, it is usually
found that some bis-aralkyl substituted thiourea is
formedl but this can be readily separated from the
desired monosubstituted product, for example by
recrystallization. It has, however, been found that
the reaction of substituted or unsubstitutad
diphenylmethylamine hydrohalides and ammonium thiocyanate
yields predominantly the bis-substituted thiourea,
although smaller amounts of the monosubstituted compounds
can be obtained in this reaction, and after separation
can be used as starting material for the novel amino-
thiazoles. It has, however, also been found that
the bis-substituted thioureas can be used as starting
material for the formation of he desired diphenylmethyl-
aminothiazoles of this invention, the bis-substituted
thiourea decomposing in situ to generate the
monosubstituted compound.
The appropriate N~aralkyl thiourea is converted to
the desired aminothiazole by reaction with an
appropriately substituted ~ -halo ketone or aldehyde of
the formula R2COCH(Z)R3, wherein R2 and R3 are as
previously defined and Z is halo, preferably chloro or
bromo. For example, when R2 is phenyl and R3 is
hydrogen, ~ -bromoacetophenone may be employed, while
when R2 and R3 are both phenyl an appropriate reagent is
a desyl halide, for example 2-chloro-2-phenyl-acetophenone.
Other appropriate ~ -halo ketones or aldehydes will be
readily selected in order to give the desired R2 and R3
substituents in the thiazole ring. The reaction is
conducted in an inert organic solvent, typically an
n-alkanol of 1 to 6 carbon atoms, preferably in absolute
- : ' . :
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:,
: ~ : :
,
L7~ 9
--6--
ethanol. Reaction temperatur~s between about 50 and
175C are employed, preferably the reflux ~emperature of
the solvent. The reaction is preferably conducted in an
inert atmosphere, for example, under nitrogen or another
inert gas. The reaction is generally essentially
complete in abou~ 1 ~o 15 hours depending on the
temperature employed, for example in about 1 to 4 hours
when using ethanol at reflux temperature. The desired
compound will be obtained as the hydrohalide salt and
the free base can then be prepared from the salt by
conventional means, for example by contacting with an
excess of a base such as an alkali metal hydroxide or
carbonate, followed by extraction of the desired free
base aminothiazole with a suitable organic solvent, for
example an ether like diethyl ether.
The pharmaceutically acceptable acid addition salts
of the novel aminothiazoles are also embraced by ~he
present invention and are readily prepared by contacting
the free base with the appropriate mineral or organic
acid in either aqueous solution or in a suitable organic
solvent. The solid salt may then be obtained by
precipitation or by evaporation of the solvent. The
pharmaceutically acceptable acid addition salts of this
invention include, but are not limited to, the hydro-
chloride, hydrobromide, hydroiodide, sulfate, bisulfate,nitrate, phosphate, acetate, lactate, maleate, fumarate,
oxalate, citratel tartrate, succinate, gluconate, methane-
sulfonate, and the like.
The novel aminothiazoles of this invention and their
pharmaceutically acceptable acid addition salts are
useful as anti-inflammatory agents and as regulants of
the immune response in warm-blooded animals. The
combination of anti-inflammatory activity and immune
regulant activity is particularly valuable in the
treatment of conditions such as rheumatoid arthritis and
.
~3 ~L79~9
--7--
other diseases associated with immune deficiency and
accompanied by inflammation. Thus, the compounds of
the present invention act to relieve the pain and
swelling associated with such conditions while also
regulating the immune response of the subject and thereby
alleviating the underlying immune disorder by maintaining
immune competence. Accordingly, the present invention
also embraces a method of treating rheumatoid arthritis
in a warm-blooded animal by administering to the subject
an effective anti-arthritic amount of an aminothiazole
of the present invention or a pharmaceutically acceptable
acid addition salt thereof. In accord with this method~
the compounds of the present invention may be
administered to the subject in need of treatment by
conventional routes, such as orally or parenterally,
dosages in the range of about 0.10 to about 50 mg/kg
body weight of the subject per day, preferably about
0.15 to about 15 mg/kg body weight per day being suitable.
However, the optimum dosage for the individual subject
being treated will be determined by the person responsible
for treatment, generally smaller doses being administered
initially and thereafter gradual increments made to
determine the most suitable dosage. This will vary
according to the particular compound employed and with
the subject being treated.
The compounds may be used in pharmaceutical
preparations containing the compound or a pharmaceutically
acceptable acid addition salt thereof in combination
with a pharmaceutically acceptable carrier or diluent.
Suitable pharmaceutically acceptable carriers include
inert solid fillers or diluents and sterile aqueous or
organic solutions. The active compound will be present
in such pharmaceutical compositions in amounts sufficient
to provide the desired dosage amount in the range
described above. Thus, for oral administration the
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compounds may be combined with a suitable solid or
liquid carrier or diluen~ to form capsules, tablets,
powders, syrups, solutions ! suspensions and the like.
The pharmaceutical compositions may, if desired, contain
additional components such as flavorants, sweeteners,
excipients and the like. For parenteral administration
the compounds may be combined with sterile aqueous or
organic media to form injectable solutions or suspensions.
For example, solutions of the aminothiazoles in sesame
or peanut oil, aqueous propylene glycol and the like
may be used, as well as aqueous solutions of water-
soluble pharmaceutically acceptable acid addition salts
of the compounds. The injectable solutions prepared in
this manner may then be administered intravenously,
interperitoneally, subcutaneously or intramuscularly,
with intravenous and interperitoneal administration
being preferred. For local treatment of inflammation
the compounds may also be administered topically in the
form of ointments, creams, pastes and the like in accord
with conventional pharmaceutical practice.
The activity of the compounds of the present
invention as anti-inflammatory agents may be determined
by pharmacological tests, for example the standard
carrageenin-induced rat foot edema test using the
general procedure described by C. A. Winter et. al.,
see Proceedings of the Society of Experimental Biology
in Medicine, Volume 111, page 544 (1962). In this test,
antiinflammatory activity is determined as the percent
inhibition of edema formation in the hind paw of male
albino rats (generally weighing about 150 to 190 grams)
`- in response to a sub-plantar injection of carrageenin.
The carrageenin is injected as a 1% aqueous suspension
1 hour after oral administration of the drug, which is
normally given in the form of an aqueous solution or
suspension. Edema formation is then assessed 3 hours
:
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L7~
after the carrageenin injection by comparing the
initial volume of the injected paw and the volume after
a 3 hour period. The increase in volume 3 hours after
carrageenin injection constitutes the individual response.
Compounds are considered active if the response between
the drug-treated animals (6 rats per group) and the
control group, i.e. the animals receiving the v~hicle
alone, is found to be significant on comparison with the
results afforded by standard compounds like acetyl-
salicyclic acid at 100 mg/kg or phenylbutazone at 33mg/kg, both by the oral route of administration.
The immune regulant activity of the compounds of
the present invention may be determined by such
pharmacological tests as the stimulation in vitro of
lymphocyte proliferation of murine thymus cells
cultured in the presence of Concanavalin A (Con A),
employing the general evaluation procedure of V. J.
Merluzzi et. al., see Journal of Clinical and
Experimental Immunology, Volume 22, page 486 (1975).
In this study, four different levels of lymphocyte
stimulation assay (LSA) activity were established for
the compounds undergoing evaluation, viz., those equal
to Con A alone; those superior to Con A activity but
less than levamisole, the standard compound of choice in
this area; those having an activity equal to levamisole;
and those having an activity greater than levamisole.
Compounds are considered to be active for the present
purposes if they are superior to Concanavalin A.
The present invention is illustrated by the
following examples. However, it should be understood
that the invention is not limited to the speci~ic details
of these examples.
Example 1
Phenethylamine (479 grams, 3.96 moles, Eastman
Scintillation Grade) was dissolved in 3500 ml of diethyl
' I
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--10--
ether and the solution was cooled to 0C. Dry hydroger.
chloride gas was bubbled through the stirred solution for
10 minutes and ~he resulting solids were filtered. The
filtrate was then cooled and hydrogen chloride was
bubbled through the solution for 10 minutes and the
solids collected. This pxocedure was repeated until
acidification of the filtrate with dry hydrogen chloride
failed to yield any precipitate. The combined solids
were dried in air and then over phosphorous pentoxide
under vacuum to provide 514 grams (82%) of phe~ethylamine
hydrochloride, m.p. 216-218C.
Phenethylamine hydrochloride (257 grams, 1.63 moles~
and ammonium thiocyanate (123.6 grams, 1.63 moles) were
heated to 160C in 340 ml bromobenzene under nitrogen.
After heating for 90 minutes, the mixture was cooled to
room temperature and then to 5C. This procedure was
repeated with a further batch of 257 grams of
phenethylamine hydrochloride. The combined solids
obtained in the above reaction were stirred in 1.5 1
water and filtered. Recrystallization from isopropyl
alcohol yielded 2~1.5 grams (45%) N-phenethyl thiourea,
m.p. 132-134.
xample 2
N-phenethyl thiourea (225 grams, 1.25 moles) and
~-bromoacetophenone (250 grams, 1.25 moles, Aldrich
Chem. Co.) in 1500 ml absolute ethanol were heatee to
reflux temperature for 2 1/2 hours under nitrogen.
After reducing the solvent volume by 10%, the reaction
mixture was cooled to room temperature and then ko 0C in
an ice bath. The solids were filtered off, redissolved
in 2,500 ml of absolute ethanol and heated to reflux.
The solvent volume was reduced to 2000 ml and the
reaction mixture cooled to 0C. This procedure was
repeated and after the second recrystallization the
solids were collected and dried under vacuum over
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-
-11
phosphorous pentoxide, yielding 365 grams (81%) of 2-
phenethylamino-4-phenylthiazole hydrobromide, m.pr 169-
17~C.
Analysis: Calcd for C17H16N2S Hsr: C, 56.50; H, 4.74;
N, 7.68
Found: C, 57.36; ~i, 5.04; N, 7.83.
- Example 3
N-phenethyl thiourea (140 grams, 0.779 moles) and desyl
bromide (225 grams, 0.82 moles~ Eastman Chem. Col in
833 ml absolute ethanol were heated at reflux temperature
for 2 hours under nitrogen, a further 300 ml of absolute
ethanol being added during the reaction. The reaction
mixture was cooled to 10C, the solids iltered,
recrystallized from absolute e~hanol and dried over
phosphorous pentoxide to yield 281.0 grams (83%) of
2-phenethylamino-4,5-diphenyl-thiazole hydrobromide,
m.p. 171-174C.
Analysis: Calcd for C23H20N2S HBr: C, 63.14; H, 4.84;
N, 6.40
Found: C, 62~62; ~, 4.82; N, 6.48.
Example 4
N-phenethyl thiourea (2~0 grams, 0.011 moles) and
~-bromopropiophenone (2.34 grams, 0.011 moles, Aldrich
Chem. Co.) in 10 ml absolute ethanol were heated to
2S re1ux temperature for 90 minutes under nitrogen. The
ethanol was then removed under vacuum, excess ethyl
acetate added and the solids filtered and dried over
phosphorous pentoxide. Recrystallization from
absolute ethanol yielded 2.86 grams (70%) of 5-me~hyl-2-
phenethylamino-4-phenylthiazole hydrobromide, m.p.
172-175C.
Analysis: Calcd for C18H18N2S HBr: C, 57.59; ~, 5.10;
N, 7.46
Found: C, 57.67; H, 5.11; N, 7.39.
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-12-
~5
Following the proc~durPs of Examples 1 and 2,
hydrohalide salts of the following compounds were
prepared:
R2
~ N
R3 S C 2 2 X
5 Salt X ~ ~ _.p.C
HBr phenyl p-methoxyphenyl hydrogen 135~139
HCl phenyl p-fluorophenyl hydrogen 163~165
~sr p-bromophenyl phenyl hydrogen 171-174
HBr p-bromophenyl phenyl methyl 150-151.5
Hsr p-methoxyphenyl phenyl hydrogen 169-171
Hsr p-methoxyphenyl phenyl methyl 149-150.5
I~sr p-methoxyphenyl phenyl phenyl 201-205
HCl p-methoxyphenyl p-fluorophenyl hydrogen 156-158
Exam~le 6
Benzylamine hydrochloride l90 grams, 0.6 moles,
Pfaltz & Bauer Co.) and ammonium thiocyanate (S0 grams,
0.66 moles) in 130 ml bromobenzene were heated to 155C
for 20 minutes to form a yellow-white suspension. After
cooling the Eiltered solids were washed three times with
water and three times with isopropyl alcohol.
Recrystallization from isopropyl alcohol and drying over
phosphorous pentoxide yielded 38.26 grams (38%) of
N-benzyl thiourea, m.p. 160-163C.
N-benzyl thiourea (2.0 grams, 0.012 moles) and
~-chloro-p-fluoroacetophenone (2.07 grams, 0.012 moles,
Aldrich Chem. Co.) in 15 ml of absolute ethanol were
heated to reflux for 2 hours under nitrogen. After
cooling the filtered solids were washed with diethyl
ether and dried over phosphorous pentoxide, yielding
3.47 grams ~91%) 2-benzylamino-4-(p-fluorophenyl)-
," ' ` ' '
~7~
-13-
thiazole hydrochloride, m.p. 192-195C.
Analysis Calcd- for C16~I13N2SF HCl: C, 59.90;
H, 4.40; N, 8.73
Found: C, 59.64; H, 4.38; N, 8.62
Example 8
Following the procedures of ~xamples 6 and 7,
hydrohalide salts of the following compounds were
prepared:
R2
N
R3 ~ ~ NH-CH2-X
Salt X ~ ~ m.p.C
HBr phenyl phenyl phenyl 250-252
HBr phenyl p-methoxyphenyl hydrogen 155-157
HBr phenyl p-chlorophenyl hydrogen 211-212
HBr phenyl phenyl methyl 157-160
7/8 HBr phenyl 2,5-dimethoxyphenyl hydrogen 159-161
HBr phenyl p-methylphenyl hydrogen 155-lS9
HBr phenyl thienyl hydrogen 100
7/8 HBr p-fluorophenyl phenyl hydrogen 84-8S
- HBr p-fluorophenyl phenyl phenyl 225~227
HCl p-fluorophenyl p-fluorophenyl hydrogen 154-158
` 20 HBr p-chlorophenyl phenyl hydrogen 176-180
HBr p-chlorophenyl phenyl methyl 148~151
Example 9
~` 2-thenylamine (30 grams, 0.265 moles, Fairfield
Chemical Co.) was dissolved in 400 ml of diethyl ether
and cooled to 0C in an ice bath. Dry hydrogen chloride
gas was bubbled through the solution for 5 minutes. The
; resulting solids were filtered and dried over phosphorous
pentoxide to yield 26.7 grams (61%) of 2-thenylamine
hydrochloride, m.p. 186-190C.
302-thenylamine hydrochloride (13.35 grams, 0.089
moles) and ammonium thiocyanate ~7.4 grams, 0.089 moles)
.~
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~ 7~
in 20 ml bromobenzene were heated to reflux temperature
for 90 minutes. The reaction mixture was cooled and the
filtered solids washed three times with water.
Recrystallization from chloroform and drying over
phosphorous pentoxide yielded 5.0 grams (33~ of N-
thenyl thiourea, m.p. 99-101C.
Analysis: Calcd for C6H8N2S2: C, 41.83; ~, 4068; N, 16.26
Found: C, 41.56 H, 4.58; N, 16.07.
Example 10
N-thenyl ~hiourea ~2.0 grams, 0.0116 moles) and
~-bromoacetophenone ~2.3 grams~ 0.0116 moles, Aldrich
Chem. Co.) in 15 ml absolute ethanol were heated to
reflux temperature for 90 minutes under nitrogen. The
reaction mixture was cooled and the ethanol removed
lS under vacuum. On dissolving the residue in hot isopropyl
alcohol and diluting with diethyl ether, an oil was
formed. The diethyl ether was decanted, the oil
dissolved in a small amount of ethanol and cooled. The
resulting solids were filtered and dried over
phosphorous pentoxide, yielding 3.20 grams (78~) of
2-thenylamino-4-phenyl-thiazole hydrobromide, m.p.
115-118C.
Analysis: Calcd for Cl4Hl2N2S2 HBr: C, 47.58; H, 3.71;
N, 7.93
Found: C, 47.75; H, 3.74; N, 7.90.
Exam~le 11
N-thenyl thiourea ~0.80 grams, 0.0046 moles) and
~-chloro-p-fluoroacetophenone (0.80 grams, 0.0046 moles,
Aldrich Chem. Co.) in ll ml absolute ethanol were
heated at reflux temperature under nitrogen for 90
minutes. After cooling, the ethanol was removed under
vacuum and the solids triturated with ethanol, iltered
and vacuum dried over phosphorous pentoxide, yielding
0.848 grams (56%) of 2-thenylamino-4(p-fluorophenyl)-
thiazole hydrochloride, m.p. 184-187C.
, , ; :, .:, . . . ..
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.,
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.
.
~15-
Analysis: Calcd for C14HllN2S2F HCl: C, 51.45; H, 3.70;
N, 8.57
Found: C, 51.41; H, 3.63; N, 8.39.
x mple 12
Followiny the procedures of Examp~es 10 and 11,
hydrohalide salts of the following compounds were
prepared:
R3 ~ ~ 2 ~ ~
Salt R R mOp.C
HBr p-methoxyphenyl hydrogen 154-158
~Br phenyl methyl 179.5-181.5
HCl thienyl hydrogen 137-142
Example 13
Furfurylamine (25.0 grams, 0.257 moles, Pfaltz &
Bauer Co.) was dissolved in 1300 ml diethyl ether and
cooled to 0C in an ice bath. Dry hydrogen chloride gas
was bubbled through the solution until no further
precipitation occurred. The solids were filtered and
dried in vacuum over phosphorous pentoxide to yield
33.46 ~97%) of furfurylamine hydrochloride, m.p.
147-149C.
Furfurylamine hydrochloride (33.46 grams, 0.250
moles) and ammonium thiocyanate (38.14 grams, 0.501
moles) in 71 ml bromobenzene were heated under nitrogen
at reflux temperature for 20 minutes and then cooled to
room temperature. The reaction mixture was mixed with
a solution of 125 ml water and 100 ml ethyl acetate and
left at room temperature overnight. The mixture was
then diluted to give 500 ml ethyl acetate and 350 ml
water and the aqueous layer separated. The organic
layer was washed with water and dried over sodium
sulfate. After filtration, the organic layer was
. ,
:
. .
.. : . "
7~9
-16-
evaporated to dryness and bromobenzene removed under
vacuum. The resulting solids were ground in a mortar
and pestle and the fine particles stirred in diethyl
ether to remove residual bromobenzene. The solids were
then filtered, washed with diethyl ether and vacuum
dried over phosphorous pentoxide, yielding 12.06 grams
t30%) of N-furfuryl thiourea, m.p. 80-91C.
Analysis: Calcd for C6H8N2OS: C, 46.14; H, 5.16; N, 17.93
Found: C, 46.91; H, 4.90; N, 17.57.
~10 Example 14
N-furfuryl thiourea (0.82 grams, 0.005 moles) and
~-bromopropiophenone [1.07 grams, 0.005 moles, Aldrich
Chem. Co.) in 11 ml absolute ethanol were heated to
reflux temperature under nitrogen for 3 hours. After
cooling to room temperature, the solvent was removed
under vacuum to give a thick brown oil, which was
triturated with five 35 ml portions of refluxing ethyl
acetate. The ethyl acetate was reduced in volume to
about 25 ml and cooled to room temperature. The
precipitated solids were filtered, washed with ethyl
acetate and vacuum dried over phosphorous pentoxide,
yielding 0.585 grams t33~) of 2-furfurylamino-S-methyl-
4-phenyl-thiazole hydrobromide, m.p. 150-153C.
Analysis: Calcd for C15H14N2OS.HBr: C, 51.29; H, 4.30;
N, 7.97
Found: C, 51.97; H, 4.47; N, 8.42.
Example 15
Following the procedure of Examples 13 and 14,
hydrohalide salts of the following compounds were
prepared:
S O
. . . ~.
d
.
;', . '. .
~7~49
Salt ~ ~ mpC
HBr phenyl hydrogen 123-126
~Br phenyl ph~nyl 192-194
Example 16
Diphenylmethylamine (25.0 grams, 0.136 moles,
Matheson, Coleman ~ Bell Co.) was dissolved in 660 ml
of diethyl ether and cooled to 0C. Dry hydxogen chloride
gas was bubbled through the solution for 10 minutes,
during which time an additional 300 ml of diethyl ether
was added to the mixture. The precipitate was filtered,
washed with diethyl ether and vacuum dried over
phosphorous pentoxide, to yield 28.3 grams (95%)
diphenylmethylamine hydrochloride, m.p. 303-310C
(decomposes).
Diphenyl~ethylamine hydrochloride ~28.3 grams,
0.129 moles) and ammonium thiocyanate (9.81 grams,
0.129 moles) in 37 ml bromobenzene were heated at reflux
temperature under nitrogen for 3 1/2 hours and then
cooled to room temperature. The solids were filtered
and triturated twice with 200 ml water. The solids
were then dissolved in 850 ml ethanol, filtered and
evaporated to a volume of about 350 ml. After cooling,
the solids were filtered, washed with ethanol and vacuum
dried over phosphorous pentoxide to yield 14.72 grams
(56~) of N,N'-bis-(diphenylmethyl) thiourea, m.p.
216-217.5C.
Analysis: Calcd for C27H24N2S: C, 79.37; H, 5.92;
N, 6.86
Found: C, 79.84; H, 6.05; N, 6.93.
Example 17
N,N'-bis-(diphenylmethyl) thiourea (1.21 grams,
0.005 moles) and desyl chloride (1.21 grams, 0.005 moles,
Aldrich Chem. Co.) in 11 ml absolute ethanol were ~-
heated to reflux temperature under nitrogen for 3 hours.
After cooling, the reaction mixture was evaporated
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to dryness, the resulting oil being mixed with about
40 ml diethyl ether. The solids were filtered, cooled
with diethyl ether and vacuum dried over phosphorous
pentoxide, yielding 1.01 grams ~75%) of 4,5-diphenyl-2-
diphenylmethylamino-thiazole hydrochloride, m.p.
195-1~8C.
Analysis: Calcd for C28H22N2S HCl: C, 73.91; H, 5O09;
N, 6.16
Found: C, 73.12; H, 5~28; N, 6.06.
Example 18
Following the procedures of Examples 16 and 17,
4-phenyl-2-diphenylmethylamino-thiazole hydrobromide
was prepared, m.p. 166-168C.
Example 19
N-phenylethylenediamine (25 grams, 0.184 moles,
Aldrich Chem. Co.) was dissolved in diethyl ether,
cooled to 0C and dry hydrogen chloride gas bubbled
through the solution until no more precipitation occurred.
The filtered solids were dried over phosphorous
pentoxide, yielding 31.2 grams (98%) N-phenylethylene-
diamine hydrochloride.
N-phenylethylenediamine hydrochloride (31.2 grams,
0.149 moles) and ammonium thiocyanate (11.3 grams,
0.149 moles) in 31 ml bromobenzene were heated to
reflux temperature under nitrogen for 2 hours. Ater
cooling, the resulting solids were filtered off and the
bromobenzene was removed from the iltrate under vacuum.
The resulting solids were stirred in 250 ml of water,
filtered and dissolved in hot isopropyl alcohol. After
cooling, the solids were filtered and dried over
- phosphorous pentoxide, yielding 2.8 grams (8%) of N-(2'~
anilinoethyl)-thiourea, m.p. 137-140C.
Analysis: Calcd for CgH13N3S: C, 55.35; H, 6~71;
N, 21.52.
Found: C, 55.64; H, 6.757 N, 21.03.
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Example 20
N-(2'-anilinoethyl)-thiourea (0O90 grams, 0.0046
moles) and~-bromoacetophenone (0.92 grams, 0.0046 moles,
~ldrich ChemO Co.) in 6 ml absolute ethanol were hea~ed
to reflux under nitrogen for 2 hours. After cooling the
reaction mixture, the solvent was removed under vacuum.
The resulting oil was dissolved in hot isopropyl alcohol,
filtered and cooled. The solids were filtered and dried
over phosphorous pentoxide, yielding 1.25 grams (73.5~)
2-~2'anilinoethylamino)-4-phenyl-thiazole, mOp. 161-165C.
Analysis: Calcd for C17H17N3S.HBr: C, 54.24; H, 4.82;
N, 11.16.
Found: C, 54.51; H, 4.59; N, 11.02.
Example 21
Following the procedures of Examples 19 and 20,
hydrohalide salts of the following compounds were
prepared:
R3 ~ ~ -NH-C~2-C~2-N~
Salt ~ ~ mpC
~Cl phenyl phenyl 139-143
HBr phenyl methyl 133-136
Example_22
The immune regulant activity of the aminothiazoles
described in Examples 2, 3, 4, 5, 7, 8, 10, 11, 12, 14,
15, 17, 18, 20 and 21 was evaluated by determining their
ability to stimulate, in itro, the lymphocyte
proliferation of murine thymus cells cultured in the
presence of Concanavalin A (Con A) by employing the
procedure of V. J. Merluzzi et. al., as essentially
described in the Journal of Clinical and ~xperimental
Immunolo~, Vol. 22, p. 486 (1975~. The cells were
derived from male C57Bl/6 mice of from 6-8 weeks age,
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purchased from the Jackson Laboratories of Bar Harbor,
Maine and the Con A was obtained from Sigma Chemicals of
St. Louis, Missouri. Each cell culture (consisting of
0.10 ml thymus cells stock solution, 0.05 ml of Con A
stock solution and 0.05 ml of drug solution) was
performed in quadruplicate and cellular proliferation
was measured, after 48 hours of incubation at 37~C., by
pulsing each culture with 3H-thymidine (0.01 ml of
specific activity 1.9 C/mM, obtained from Schwarz-Mann,
Inc. of Orangeburg, N.Y.) and then determining the
incorporation of 3H-~hymidine into cellular
desoxyribonucleic acid (DNA) by an assessment of
radioactivity using a liquid scintillation counter.
The resul~s obtained in this manner are expressed
quantitatively in terms of the average counts per minute
(cpm) of 3H-thymidine incorporated at the drug level
with maximum activity by the quadruplicate cell cultures.
These quadruplicate determinations are employed at eight
different concentrations of drugs in the range 0.02 to
50~g/ml. The highest cpm value obtained is employed in
the scoring system. On this basis, four different levels
of activity were established in the present lymphocyte
stimulation assay (LSA) and these are defined in the
manner hereinafter indicated, viz., those levels equal
to Con A alone (6,000 ~ 300 cpm) were assigned a
negative value or score of zero; those superior (10,000
+ 700 cpm) to Con A activity but less than levamisole
were scored as ~; while those equal to levamisole l~2,000
+ 900 cpm) were scored as ~ and those having an
activity (27,000 1 1,000 cpm~ greater than levamisole
were scored as ~++. The LSA activity for the compounds
described in the above Examples was +~ in each case.
E~ple 23
The anti-inflammatory activity of aminothiazoles
of this invention was determined using the standard
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carrageenin-induced rat foo~ edema test, according to
the procedure essentially as described by C. A . Winter
et. al., and reported in the Proceedings of the Society
for Experimental Biology and Medicine, Vol. 111, p. 544
(1962). The compounds were administered orally in the
form of their previously reported hydrohalide salts at
a dose level of 33 mg/kg. The results obtained in
this manner are presented in the table below in terms
of the p~rcent inhibition of edema formation afforded
by each test compound as compared to the non-drug
treated control (i.e., aqueous solution with no compound~:
R
2\~___N
R3 ~ ~ NH R
S HZ
% Inhibition of
HZ ederna (33 mg/kg, p.o.)
benzyl phenyl phenyl HCl 33
4-fluoro- phenyl hydrogen HBr 41
benzyl
2-thenyl 4-fluorophenyl hydrogen HBr 49
2-phenethyl phenylhydrogen HBr 47
2-phenethyl phenylphenyl HBr 48
4-methoxy- 4-fluoro-hydrogen HBr 29
phenethyl phenyl
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