NZ190623A

NZ190623A - Substituted 2-aminothiazoles and pharmaceutical compositions containing them

Info

Publication number: NZ190623A
Application number: NZ190623A
Authority: NZ
Inventors: J G Lombardino
Original assignee: Pfizer
Priority date: 1978-06-02
Filing date: 1979-06-01
Publication date: 1984-07-06
Also published as: SE438333B; IL57450A0; FI68820C; NO150760C; NO791831L; ATA401679A; AU4763479A; YU40997B; GB2022085B; DD144055A5; IT1121238B; NO150760B; FI68820B; SE7904798L; YU128879A; JPS5936988B2; FR2427333B1; NL7904337A; AT373248B; HK66487A

Description

New Zealand Paient Spedficaiion for Paient Number 1 90623 1 906 23 NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION "NOVEL AMINOTHIAZOLES" We, PFIZER INC., a corporation organized under the laws of the State of Delaware, United States of America of 235 East 42nd Street, New York, State of New York, United States of America hereby declare the invention for whichxl / we pray that a patent may be granted /us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 (followed by page la) \ 906 23 Novel Aminothiazoles This invention relates to novel substituted aminothiazoles useful for relieving inflammatory conditions and as immune regulants.

A number of compounds have been known 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-l,2-benzothiazine-4-carboxamide-1,1-dioxides, such as those disclosed in 10 United States Patent No. 3,591,584. Accordingly, these compounds have been of therapeutic value in the treatment of arthritic and other inflammatory conditions such as rheumatoid 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 (1977) 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 30 example 2-phenethylaminothiazole, Chem. Abs. 59, 1613e (1963); 2-benzylaminothiazole, J.A.C.S., 7£, 2272 (1952) 1 9 *7 and 2-benzylamino-4-phenyl-thiazole, J. Ind. Chem. Soc., 44, 57 (1967). These articles do not, however, disclose any pharmacological activity of such compounds.

This invention relates to substituted aminothiazoles useful as anti-inflammatory agents and as regulants of the body immune response. More particularly, the novel compounds of this invention are those of the formula -N ' ^ V J. P. & S. ■$~$o an<^ the pharmaceutically acceptable acid addition salts — Xx -ch2-CH^-^ thereof, wherein R, is selected from -CH , (Oil,.) -*y, £ n -CH -CH -NH-X and -(CH0) Y, wherein X is selected from » 2 m 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, A. J. P. & S. is I or 2 bromo and fluoro; n-and mi aro each an xntujUT—fl'UHl 1—to I ^ -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 R^ 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, with the-~ j p & £ proviso^, that a-is nob-1 when both X and R^ aire, phenyl fay and -Rj ■ ia liy drug till. ■ Preferred substituents for R£ are <r ..phenyl and p-fluorophenyl and for R^ are hydrogen and phenyl.

I p _3. 1 90S A" pr<?^rreoL Q"f C&fl*j>c>usAs UjCv/sr<s?tA R( ts CHx-CLH^-)<-. ft -preferred yroup u'f eeimpeunda ia fchaL wheifcin T?^ io ■ (GII^) "X, espeulally h is 1. Most preferred are those compounds where X is phenyl or p-methoxy phenyl, is phenyl or p-fluorophenyl, is 5 phenyl, methyl or hydrogen, including 2-phenethyl- amino-4-phenyl-thiazole, 2-phenethylamino-4,5-diphenyl-thiazole and 2-phenethylamino-5-methyl-4-phenyl-thiazole.

A further group of interest is that wherein R^ is -(CH.) -Y, especially where m is 1. Preferred groups 2 m for Y are thienyl and furyl, especially those compounds where R^ is phenyl or p-fluorophenyl and R^ is hydrogen, methyl and phenyl.

Yet a further group of compounds are those wherein R. is -CH , preferred compounds being those where X 1 X is phenyl, R^ is phenyl and R^ is hydrogen or phenyl.

Another group of compounds of interest are those wherein R is -CH_-CH -NH-X, especially those compounds ■i « 6 where X is phenyl, R2 is phenyl and R^ is hydrogen.

Also embraced by the present invention are 20 pharmaceutical compositions comprising a novel substituted aminothiazole of this invention, as described above herein, or a pharmaceutically acceptable acid addition salt thereof, together with a pharmaceutically acceptable carrier or diluent. Preferred pharmaceutical 25 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-methoxyphenethylamino)-4-(p-fluorophenyl)-thiazole or pharmaceutically 30 acceptable acid addition salts of these compounds.

AJso claimed is a method of treating rheumatoid arthritis in a host which comprises administering to said host an effective anti-arthritic amount of a riovel aminothiazole of this invention, especially those 35 preferred compounds described above and most preferably 1 906 2 2-phenethy1amino-4-pheny1-thiazole, 2-(p-methoxyphen-ethylamino)-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 R^NH^NI^, where R^ is as previously defined. The latter compounds are readily prepared from known and readily available amines of the formula R^NH^. For example, when the group R^ is ~^CH2^n~X/ unsu^stitute<^ or appropriately substituted benzylamines (where n is 1) and phenethylamines (where n is 2) are employed. Corresponding thenyl or furyl analogs of these amines will be used to prepare compounds where Rn is -(CH_) -Y. Where Rn is -CH^ , unsubstituted J. jl rn x ^ or substituted diphenylmethylamines are appropriate starting materials, while when R^ is -CH2~CH2-NH-X, unsubstituted or substituted n-phenethylenediamines are employed. In the above, X, Y, n and m are as previously 20 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 solution of the amine in an inert organic solvent, typically an ether 25 such as diethyl ether, at a temperature of about -10°C to about 10°C. The amine hydrohalide salt is then reacted with ammonium thiocyanate or an alkali metal thiocyanate, such as potassium thiocyanate, in an inert organic solvent, generally an aromatic solvent such as 30 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 110°C to about 250°C, preferably 150°C to 200°C, 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 1 to 3 hours at 150 to 200°C. In preparing the N-aralkyl thioureas as described above, it is usually found that some bis-aralkyl substituted thiourea is formed, 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 unsubstituted 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 aminothiazoles. It has, however, also been found that the bis-substituted thioureas can be used as starting material for the formation of the 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 o<. -halo ketone or aldehyde of the formula R2COCH(Z)R3, wherein R2 and R^ are as previously defined and Z is halo, preferably chloro or bromo. For example, when R2 is phenyl and R3 is hydrogen, c-c -bromoacetophenone may be employed, while when R2 and R^ are both phenyl an appropriate reagent is a desyl halide, for example 2-chloro-2-phenyl-acetophenone. Other appropriate o<. -halo ketones or aldehydes will be readily selected in order to give the desired R and R « J 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 ethanol. Reaction temperatures between about 50° and 175°C are employed, preferably the reflux temperature of the solvent. The reaction is preferably conducted in an inert atmosphere, for example, under nitrogen or another 5 inert gas. The reaction is generally essentially complete in about 1 to 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 10 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 15 example an ether like diethyl ether.

The pharmaceutically acceptable acid addition salts of the novel aminothiazoles are also embraced by the present invention and are readily prepared by contacting the free base with the appropriate mineral or organic 20 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-25 chloride, hydrobromide, hydroiodide, sulfate, bisulfate, nitrate, phosphate, acetate, lactate, maleate, fumarate, oxalate, citrate, tartrate, succinate, gluconate, methane-sulfonate, and the like.

The novel aminothiazoles of this invention and their 30 pharmaceutically acceptable acid addition salts are useful as anti-inflammatory agents and asv regulants of the immune response in warm-blooded animals. The combination of anti-inflammatory activity and immune regulant activity is particularly valuable in the 35 treatment of conditions such as rheumatoid arthritis and 1 906 2 3 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 5 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 10 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 15 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 20 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 25 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. 30 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 35 described above. Thus, for oral administration the compounds may be combined with a suitable solid or liquid carrier or diluent to form capsules, tablets, powders, syrups, solutions, suspensions and the like. The pharmaceutical compositions may, if desired, contain 5 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 10 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, 15 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 20 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 25 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 30 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 35 suspension. Edema formation is then assessed 3 hours 1 906 2 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 5 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 vehicle alone, is found to be significant on comparison with the results afforded by standard compounds like acetyl-10 salicyclic acid at 100 mg/kg or phenylbutazone at 33 mg/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 15 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). 20 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 25 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 30 following examples. However, it should be understood that the invention is not limited to the specific details of these examples.

Example 1 Phenethylamine (479 grams, 3.96 moles, Eastman 35 Scintillation Grade) was dissolved in 3500 ml of diethyl 1 906 2 ether and the solution was cooled to 0°C. Dry hydrogen chloride gas was bubbled through the stirred solution for 10 minutes and the 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 procedure 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 phenethylamine hydrochloride, m.p. 216-218°C.

Phenethylamine hydrochloride (257 grams, 1.63 moles) and ammonium thiocyanate (123.6 grams, 1.63 moles) were heated to 160°C in 340 ml bromobenzene under nitrogen. After heating for 90 minutes, the mixture was cooled to room temperature and then to 5°C. 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 61.5 grams (45%) N-phenethyl thiourea, m.p. 132-134°.

Example 2 N-phenethyl thiourea (225 grams, 1.25 moles) and c<-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 to 0°C 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 0°C. This procedure was repeated and after the second recrystallization the solids were collected and dried under vacuum over 1 906 2 phosphorous pentoxide, yielding 365 grams (81%) of 2-phenethylamino-4-phenylthiazole hydrobromide, m.p. 169-172°C.

Analysis: Calcd for C._H N S'HBr: C, 56.50; H, 4.74; 17 lb 2.

N, 7.68 Found: C, 57.36; H, 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. Co) in 10 833 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 10°C, the solids filtered, recrystallized from absolute ethanol and dried over 15 phosphorous pentoxide to yield 2 81.0 grams (83%) of 2-phenethylamino-4,5-diphenyl-thiazole hydrobromide, m.p. 171-174°C.

Analysis: Calcd for C23H2QN2s*HBr: C' 63»14/ 4.84; N, 6.40 Found: C, 62.62; H, 4.82; N, 6.48.

Example 4 N-phenethyl thiourea (2.0 grams, 0.011 moles) and c*-bromopropiophenone (2.34 grams, 0.011 moles, Aldrich Chem. Co.) in 10 ml absolute ethanol were heated to 25 reflux 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-methyl-2-30 phenethylamino-4-phenylthiazole hydrobromide, m.p. 172-175°C.

Analysis: Calcd for C^gH^gN2S*HBr: C, 57.59; H, 5.10; N, 7.46 Found: C, 57.67; H, 5.11; N, 7.39. 1 906 Example 5 Following the procedures of Examples 1 and 2, hydrohalide salts of the following compounds were prepared: r. nh-ch2-ch2-x Salt X 3* ^9- m.p.

°C HBr phenyl p-methoxyphenyl hydrogen 135- 139 HC1 phenyl p- •fluorophenyl hydrogen 163- 165 HBr p-bromophenyl phenyl hydrogen 171- 174 HBr p-bromophenyl phenyl methyl 150- 151.5 1° HBr p-methoxyphenyl phenyl hydrogen 169- 171 HBr p-methoxyphenyl phenyl methyl 149- 150.5 HBr p-methoxyphenyl phenyl phenyl 201- 205 HC1 p-methoxyphenyl p-fluorophenyl hydrogen 156- 158 Example 6 Benzylamine hydrochloride (90 grams, 0.6 moles, Pfaltz & Bauer Co.) and ammonium thiocyanate (50 grams, 0.66 moles) in 130 ml bromobenzene were heated to 155°C for 20 minutes to form a yellow-white suspension. After cooling the filtered 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. 160-163°C.

Example 7 N-benzyl thiourea (2.0 grams, 0.012 moles) and oi-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)- 1 90S 2 thiazole hydrochloride, m.p. 192-195°C.

Analysis: Calcd. for C16H13N2SF*HC1: 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 Examples 6 and 7, hydrohalide salts of the following compounds were prepared: Salt X R» R_ m.p . °C —2- —3- 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 -159 HBr phenyl thienyl hydrogen 100 7/8 HBr p-fluorophenyl phenyl hydrogen 84-: 85 HBr p-fluorophenyl phenyl phenyl 225 -227 HC1 p-fluorophenyl p-fluorophenyl hydrogen 154 -158 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 0°C 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 2 6.7 grams (61%) of 2-thenylamine hydrochloride, m.p. 186-190°C. 2-thenylamine hydrochloride (13.35 grams, 0.089 moles) and ammonium thiocyanate (7.4 grams, 0.089 moles) 1 906 2 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 5 phosphorous pentoxide yielded 5.0 grams (33%) of N-thenyl thiourea, m.p. 99-101°C.

Analysis: Calcd for C.H.N S: C, 41.83; H, 4.68; N, 16.26 o 8 2 2 Found: C, 41.56; H, 4.58; N, 16.07.

Example 10 N-thenyl thiourea (2.0 grams, 0.0116 moles) and o<.-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 15 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 20 phosphorous pentoxide, yielding 3.20 grams (78%) of 2-thenylamino-4-phenyl-thiazole hydrobromide, m.p. 115-118°C.

Analysis: Calcd for c14H12N2S2*HBr: C' 47-58' H' 3-71» N, 7.93 Found: C, 47.75; H, 3.74; N, 7.90.

Example 11 N-thenyl thiourea (0.80 grams, 0.0046 moles) and oc-chloro-p-fluoroacetophenone (0.80 grams, 0.0046 moles, Aldrich Chem. Co.) in 11 ml absolute ethanol were 30 heated at reflux temperature under nitrogen for 90 minutes. After cooling, the ethanol was removed under vacuum and the solids triturated with ethanol, filtered and vacuum dried over phosphorous pentoxide, yielding 0.848 grams (56%) of 2-thenylamino-4(p-fluorophenyl)-35 thiazole hydrochloride, m.p. 184-187°C. 190623 Analysis: Calcd for C^H^N^F'HCl: C, 51.45; H, 3.70; N, 8.57 Found: C, 51.41; H, 3.63; N, 8.39.

Example 12 Following the procedures of Examples 10 and 11, hydrohalide salts of the following compounds were prepared: \Wc„._/~A Salt R„ m.p.°C —t -3- —c HBr p-methoxyphenyl hydrogen 154-158 HBr phenyl methyl 179.5-181.5 HC1 thienyl hydrogen 137-142 Example 13 Furfurylamine (25.0 grams, 0.257 moles, Pfaltz & Bauer Co.) was dissolved in 1300 ml diethyl ether and 15 cooled to 0°C 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. 20 147-149°C.

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 25 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 30 layer was washed with water and dried over sodium sulfate. After filtration, the organic layer was 1 906 2 3 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 (30%) of N-furfuryl thiourea, m.p. 80-91°C.

Analysis: Calcd for C H N OS: C, 46.14; H, 5.16; N, 17.93 6 8 2 Found: C, 46.91; H, 4.90; N, 17.57.

Example 14 N-furfuryl thiourea (0.82 grams, 0.005 moles) and o^-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 (33%) of 2-furfurylamino-5-methyl- 4-phenyl-thiazole hydrobromide, m.p. 150-153°C.

Analysis: Calcd for C,_H N OS.HBr: C, 51.29; H, 4.30; 14 2 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 30 prepared: -n \.-nh-ch2 1 906 23 Salt Rj mp°C HBr phenyl hydrogen 123-126 HBr phenyl phenyl 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 0°C. Dry hydrogen chloride gas was bubbled through the solution for 10 minutes, during which time an additional 300 ml of diethyl ether 10 was added to the mixture. The precipitate was filtered, washed with diethyl ether and vacuum dried over phosphorous pentoxide, to yield 2 8.3 grams (95%) diphenylmethylamine hydrochloride, m.p. 303-310°C (decomposes).

Diphenylmethylamine 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 20 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 25 (56%) of N,N'-bis-(diphenylmethyl) thiourea, m.p. 216-217.5°C.

Analysis: Calcd for C27H24N2S: C/ H' 5.92; N, 6.86 Pound: C, 79.84; H, 6.05; N, 6.93. 30 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. 35 After cooling, the reaction mixture was evaporated 1 90S 2 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-2-5 diphenylmethylamino-thiazole hydrochloride, m.p. 195-198°C.

Analysis: Calcd for C H N S*HC1: C, 73.91; H, 5.09; 2o 22 2 N, 6.16 Found: C, 73.12; H, 5.28; N, 6.06. 10 Example 18 Following the procedures of Examples 16 and 17, 4-phenyl-2-diphenylmethylamino-thiazole hydrobromide was prepared, m.p. 166-168°C.

Example 19 N-phenylethylenediamine (25 grams, 0.184 moles, Aldrich Chem. Co.) was dissolved in diethyl ether, cooled to 0°C and dry hydrogen chloride gas bubbled through the solution until no more precipitation occurred. The filtered solids were dried over phosphorous 20 pentoxide, yielding 31.2 grams (98%) N-phenylethylenediamine 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 25 reflux temperature under nitrogen for 2 hours. After cooling, the resulting solids were filtered off and the bromobenzene was removed from the filtrate under vacuum. The resulting solids were stirred in 250 ml of water, filtered and dissolved in hot isopropyl alcohol. After 30 cooling, the solids were filtered and dried over phosphorous pentoxide, yielding 2.8 grams (8%) of N-(2'-anilinoethyl)-thiourea, m.p. 137-140°C.

Analysis: Calcd for CgHi3N3S: C' 55.35; H, 6.71; • N, 21.52.

Found: C, 55.64; H, 6.75; N, 21.03.

Example 20 N-(2'-anilinoethyl)-thiourea (0.90 grams, 0.0046 moles) and c<-bromoacetophenone (0.92 grams, 0.0046 moles, Aldrich Chem. Co.) in 6 ml absolute ethanol were heated 5 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%) 10 2 — (2'anilinoethylamino)-4-phenyl-thiazole, m.p. 161-165°C. Analysis: Calcd for C^H^N^S.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: Salt Rj mp°C HC1 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 25 ability to stimulate, in vitro, 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 Experimental 30 Immunology, Vol. 22, p. 486 (1975). The cells were derived from male C57B1/6 mice of from 6-8 weeks age, ? ^ %J o 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 3 pulsing each culture with H-thymidine (0.01 ml of specific activity 1.9 C/mM, obtained from Schwarz-Mann, Inc. of Orangeburg, N.Y.) and then determining the 3 incorporation of H-thymidine into cellular desoxyribonucleic acid (DNA) by an assessment of radioactivity using a liquid scintillation counter. The results obtained in this manner are expressed quantitatively in terms of the average counts per minute 3 (cpm) of H-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/X-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 (22,000 +_ 900 cpm) were scored as ++ and those having an activity (27,000 + 1,000 cpm) greater than levamisole were scored as +++. The LSA activity for the compounds described in the above Examples was +++ in each case.

Example 23 The anti-inflammatory activity of aminothiazoles of this invention was determined using the standard

Claims

A -21- 906 23 10 15 20 carrageenin-induced rat foot 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. Ill, 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 percent 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, 5* H phenyl phenyl phenyl phenyl HZ phenyl HC1 hydrogen HBr benzyl 4-fluoro-benzyl 2-thenyl 4-fluorophenyl hydrogen HBr 2-phenethyl 2-phenethyl 4-methoxy-phenethyl 4-fluorophenyl hydrogen HBr phenyl HBr hydrogen HBr % Inhibition of edema (33 mg/kg, p.o.) 33 41 49 47 48 29 22 1 9062 What we Claim is:

1. A compound of the formula R 2 R 3 -NH-R1 and the pharmaceutically acceptable acid addition salts thereof, wherein is selected from the group consisting Of -CH^X , -CH2-CH2-X, -CH2-CH2-NH-X and -(CH^Y, wherein X is selected from the group consisting of phenyl and monosubstituted phenyl, said substituent being selected from the group consisting of alkyl of 1 to 3 carbon atoms, hydroxy, alkoxy of 1 to 3 carbon atoms, chloro, bromo and fluoro; Y is selected from the group consisting of thienyl, monosubstituted thienyl, furyl and monosubstituted furyl said substituent being selected from the group consisting of alkyl of 1 to 3 carbon atoms, chloro, bromo and fluoro; m is 1 or 2; R2 is selected from the group consisting of phenyl, thienyl, and monosubstituted phenyl, said substituent being selected from the group consisting of alkyl of 1 to 3 carbon atoms, hydroxy, alkoxy of 1 to 3 carbon atoms, chloro, bromo and fluoro; and R^ is selected from the group consisting of hydrogen, alkyl of 1 to 3 carbon atoms, phenyl and monosubstituted phenyl, said substituent being selected from the group consisting of alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms, bromo, chloro and fluoro.

2. A compound of Claim 1 wherein is -CH2-CH2~X.

3. A compound of Claim 2 wherein X is phenyl, R2 is phenyl, and R^ is hydrogen, methyl or phenyl.

4. A compound of Claim 3 wherein R^ is hydrogen. - 23 - 1 90623

5. A compound of Claim 2 wherein X is p-methoxyphenyl, R2 is p-fluorophenyl and is hydrogen.

6. A compound of Claim 1 wherein R. is -(CH_) -Y 12m

7. A compound of Claim 6 wherein Y is thienyl, m is 1, R2 is phenyl or p-fluorophenyl and is hydrogen.

8. A compound of Claim 6 wherein Y is furyl, m is 1, R2 is phenyl and R^ is hydrogen, methyl or phenyl. Y

9. A compound of Claim 1 wherein R^ is -CH^X , X is phenyl, R2 is phenyl and R^ is hydrogen or phenyl.

10. A compound of Claim 1 wherein R1 is -CF^-CE^-NH-X, X is phenyl, R2 is phenyl and R^ is hydrogen.

11. A pharmaceutical composition comprising an immune-regulant effective amount of a compound of Claim 1 and a pharmaceutically acceptable carrier.

12. A composition of Claim 11 wherein the compound is 2-(1-phenylethylamino)-4-phenyl-thiazole.

13. A composition of Claim 11 wherein the compound is 2-thenylamino-4-(p-fluorophenyl)-thiazole.

14. A composition of Claim 11 wherein the compound is 2-(p-methoxyphenethylamino)-4-(p-fluorophenyl)-thiazole.

15. A compound as claimed in any one of claims 1 to 10 substantially as hereinbefore described with reference to any of the examples.

16. A pharmaceutical composition as claimed in any one of the claims 11 to 14 substantially as hereinbefore described with reference to any of the examples. 90623 -an.-

17. A method of treating rheumatoid arthritis in a warm-blooded non-human animal which comprises administering to or feeding to the animal an effective anti-arthritic amount of a compound as claimed in any one of claims 1 to 10 and 15 or a composition as claimed in any one of claims 11 to 14 and 16.

18. A method as claimed in claim 17 wherein said compound or the ami- J. P. & S -ted nothiazole or its acid addition salt is administered or -self-administered at a dosage of 0.10 to 50 mg/kg body weight.

19. A method as claimed in claim 18 wherein the dosage is from 0.15 to 15 mg/kg body weight.

20. A method as claimed in any one of claims 17 to 19 when performed substantially as hereinbefore described. bated this dav of A. J. PARK & SON per agents for the applicants