NO150760B - ANALOGY PROCEDURE FOR THE PREPARATION OF THERAPEUTIC ACTIVE AMINOTIAZOLES - Google Patents

Abstract

Analogous process for the preparation of therapeutically active aminothiazoles.

Description

The present invention relates to the production of new, substituted aminothiazoles for use in alleviating inflammatory conditions and with an immune-regulating effect.

A number of compounds are known within this field

to be useful as anti-inflammatory agents, e.g. the corticosteroids, phenylbutazone, indomethacin and various 3,4-dihydro-4-oxo-2H-1,2-benzothiazine-4-carboxamide-1,1-dioxides, such as those described in US patent 3,591,584. These compounds have therefore been of therapeutic value in the treatment of arthritic and other inflammatory conditions such as e.g. rheumatoid arthritis. Such conditions have also been treated by administering immune-regulatory agents, e.g. levamisole, as for example described 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 new aminothiazoles have a particularly

desirable combination of pharmacological properties, namely that they are active both as anti-inflammatory agents and as regulators of the body's immune response. They are therefore of particular value in the treatment of rheumatoid arthritis and other conditions where relief of the inflammation and regulation of the body's immune response is desirable.

The synthesis of a limited number of 2-aralkyl-aminothiazoles

is described in the subject area, e.g. 2-phenethyl-aminothiazole, chem.

Abs. 59, 1613e (1963); 2-Benzylaminothiazole, J.A.C.S., 74, 2272

(1952) and 2-benzylamino-4-phenylthiazole, J. Ind. Chem. Soc., 44, 57 (1967). However, these articles do not describe any pharmacological activity of these compounds. The present invention relates to the production of substituted aminothiazoles which are useful as anti-inflammatory agents and as regulatory agents for the body's immune response. More in particular, the new compounds produced according to the invention are those which have the following formula:

and the pharmaceutically acceptable acid addition salts thereof, wherein phenyl or monosubstituted phenyl, said substituent being alkyl of 1 to 3 carbon atoms, chlorine, bromine or fluorine; Y is thienyl, monosubstituted thienyl, furyl or monosubstituted furyl, said substituent being alkyl of 1 to 3 carbon atoms, chlorine, bromine or fluorine; m is a number from 1 to 2; R 2 is phenyl, thienyl or monosubstituted phenyl, said substituent being alkyl with 1 to 3 carbon atoms, hydroxy, alkoxy with 1 to 3 carbon atoms, chlorine, bromine or fluorine; and R 1 is hydrogen, alkyl of 1 to 3 carbon atoms, phenyl or monosubstituted phenyl, said substituent being alkyl of 1 to 3 carbon atoms, alkoxy of 1 to 3 carbon atoms, chlorine, bromine or fluorine. Preferred substituents for R2 are phenyl and p-fluorophenyl and for R, hydrogen and phenyl. A preferred group of compounds is that where R 2 is -(CH 2 ) 2 -X. Most preferred are those compounds where X is phenyl or p-methoxyphenyl, R 2 is phenyl or p-fluorophenyl; R 1 is phenyl, methyl or hydrogen, including 2-phenethylamino-4-phenylthiazole, 2-phenethylamino-4,5-diphenylthiazole and 2-phenethylamino-5-methyl-4-phenylthiazole. A further group of interest is that where R 2 is -(CH 2 )m-Y-, especially where m is 1. Preferred groups for Y are thienyl and furyl, especially those compounds where R 2 is phenyl or p-fluorophenyl and R 2 is hydrogen, methyl and phenyl.

A further group of compounds are those where R^ is

preferred compounds being those where X is phenyl, R 2 is

phenyl and R 1 is hydrogen or phenyl.

Another group of compounds of interest are those where R 1 is -CH 2 -CH 2 -NH-X, especially those where X is phenyl, R 2 is phenyl and R 1 is hydrogen.

With the help of the compounds produced according to the invention, one can e.g. treat rheumatoid arthritis in a patient, by administering to said patient an effective anti-arthritic amount of a new aminothiazole produced according to the invention, especially the preferred compounds described above and most preferably 2-phenethylamino-4-phenyl-thiazole, 2- (p-methoxyphenethylamino)-4-(p-fluorophenyl)-thiazole or 2-tenylamino-4-(p-fluorophenyl)-thiazole or pharmaceutically acceptable acid addition salts thereof.

The new aminothiazoles are prepared according to the invention from suitably substituted N-arylthiourea with the formula

where R1 is as previously defined. The latter compounds are easily prepared from known and readily available amines with the formula R^NH2. When, for example, the group is -(CH2)2-X, unsubstituted or suitably substituted phenethylamines are used. Corresponding tenyl or furyl analogues of these amines are used to prepare compounds where R^ is -(CH2)m~Y. Where R^ is

are unsubstituted or substituted diphenylmethylamines

suitable starting materials, while when is -CH2~CH2NH-X unsubstituted or substituted n-phenethylenediamines are used. In the above description, X, Y and m are as previously defined. The amine starting materials are first converted to the hydrochlorides or other hydrohalide salts, generally by reaction with hydrogen chloride or other hydrogen halides, generally by bubbling the gas into a solution of the amine in an inert solvent, typically an ether e.g. diethyl ether, at a temperature of approx. -10 to approx. 10°C. The amine hydrogenide 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 bromobenzene, chlorobenzene, xylene

and the like, to form the desired N-aralkylthiourea. The reaction is preferably carried out in an inert atmosphere, e.g. under nitrogen, at a temperature from approx. 110 to approx. 250, preferably 150 to 200, C°, e.g. at the reflux temperature in bromobenzene. The reaction will generally be complete within approx. 30 minutes to approx. 6 hours depending on the temperature used, generally within 1 to 3 hours at 150 to 200°C. When preparing N-aralkylthiourea as described above, it is usually found that some bis-aralkyl-substituted thiourea is formed, but this can be easily separated from the desired monosubstituted product, for example by recrystallization. However, it has been found that the reaction between substituted or unsubstituted diphenylmethylamine hydrohalides and ammonium thiocyanate predominantly gives bis-substituted thiourea, although smaller amounts of mono-substituted compounds can be obtained in this reaction, and after separation the former can be used as starting material for the new aminothiazoles. However, it has also been found that bis-substituted thiourea can be used as starting material for the formation of the desired diphenylmethylaminothiazoles, bis-substituted thiourea being cleaved in situ to give the monosubstituted compound.

The appropriate N-aralkyl-thiourea is converted to the desired aminothiazole by reaction with a suitably substituted α-halo-ketone or -aldehyde of the formula R 2 COCH(Z)R 3 # where R 2 and R 3 are as previously defined and Z is halogen, preferably chlorine or bromine. When R2 is phenyl and R^ is hydrogen, for example a-bromoacetophenone can be used, while when R2 and R^ are both phenyl, a suitable reagent is a decyl halide, e.g. 2-chloro-2-phenyl-acetophenone. Other suitable α-halo ketones or aldehydes can be readily selected to provide the desired R 2 - and R 4 -substituents in the thiazole ring. The reaction is carried out in an inert organic solvent, typically an n-alkanol with 1 to 6 carbon atoms, preferably in absolute ethanol. Reaction temperatures between approx. 50 and 175°C, preferably the reflux temperature for the solvent is used. The reaction is preferably carried out in an inert atmosphere, e.g. under nitrogen or another inert gas. The reaction is generally essentially complete within approx. 1 to 15 hours depending on the temperature used, e.g. during approx. 1 to 4 hours when using ethanol at reflux temperature. The desired compound is obtained as the hydrohalide salt and the free base can then be prepared from the salt by conventional methods, e.g. by bringing it into contact with an excess base, such as an alkali metal hydroxide or carbonate, followed by extraction of the desired free aminothiazole base with a suitable organic solvent, e.g. an ether such as diethyl ether.

The pharmaceutically acceptable acid addition salts of the new aminothiazoles can also be prepared according to the invention, e.g. by bringing the free base into contact with the appropriate mineral or organic acid either in aqueous solution or in a suitable organic solvent. The solid salt can then be obtained by precipitation or evaporation of the solvent. The pharmaceutically acceptable acid addition salts include, but are not limited to, the hydrochloride, hydrobromide, hydroiodide, sulfate, bisulfate, nitrate, phosphate, acetate, lactate, maleate, fumarate, oxalate, citrate, tartrate, succinate, gluconate, methanesulfonate and the like.

The new aminothiazoles produced according to the invention and their pharmaceutically acceptable acid addition salts are useful as anti-inflammatory agents and as regulators of the immune response in warm-blooded animals. The combination of anti-inflammatory activity and immune-regulating activity is particularly valuable in the treatment of conditions such as e.g. rheumatoid arthritis and other diseases associated with immune deficiency and accompanied by inflammation. The compounds produced according to the invention thus relieve pain and swelling associated with such conditions, while at the same time regulating the immune response in the patient and thereby alleviating the underlying immune disorder by maintaining immune competence. The compounds produced according to the invention can therefore also be used for the treatment of rheumatoid arthritis in warm-blooded animals by administering to the patient an effective anti-arthritic amount of an aminothiazole produced according to the invention or a pharmaceutically acceptable acid addition salt thereof. According to this method, the new compounds can be administered to the patient in need of treatment via conventional routes, e.g. orally or parenterally, suitably in doses in the range of approx. 0.10 to approx. 50 mg/kg body weight per day, preferably approx. 0.15 to approx.

15 mg/kg. However, the optimal dosage for the individual patient to be treated is determined by the person responsible for the treatment, as smaller doses are usually administered to begin with and these are then gradually increased to determine the most suitable dosage. This will vary according to the particular compound used and the patient being treated.

The compounds can 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 preparations in amounts sufficient to provide the desired dosage amount in the range 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 preparations may, if desired, contain additional ingredients, e.g. flavourings, sweeteners, binders and the like. For parenteral administration, the compounds may be combined with sterile, aqueous or organic media to form injectable solutions or suspensions. Solutions of aminothiazoles in sesame or peanut oil, aqueous propylene glycol and the like can for example be used, as well as aqueous solutions of water-soluble, pharmaceutically acceptable acid addition salts of the compounds. The injectable solutions prepared in this way can then be administered intravenously, interperitoneally, subcutaneously or intramuscularly, intravenous and interperitoneal administration being preferred. For local treatment of inflammation, the compounds can also be administered locally in the form of ointments, creams, pastes and the like according to conventional pharmaceutical practice.

The activity of the new compounds as anti-inflammatory agents can be determined by pharmacological tests, e.g. the carrageenan-induced rat foot edema standard test using the general procedure described by CA. Winter et al., see Proceedings of the Society of Experimental Biology in Medicine, Volume 111, Page 544 (1962). In this test, anti-inflammatory activity is determined as percent inhibition of edema formation in the hind paw of albino male rats (usually weighing about 150-190 grams) in response to a sub-plantar injection of carrageenan. The carrageenan is injected as a 1% aqueous suspension 1 hour after oral administration of the medicine, which is normally given in the form of an aqueous solution or suspension. Edema formation is then determined 3

hours after the carrageenan 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 carrageenan injection constitutes the individual response. Compounds are considered active if the response between drug-treated animals (6 rats per group) and the control group, i.e. animals receiving only the vehicle is found to be significant when compared with the results obtained with standard compounds such as acetylsalicylic acid in an amount of 100 mg/kg or phenylbutazone in an amount of 33 mg/kg, both administered orally.

The immunoregulatory activity of the compounds prepared according to the invention can be determined by such pharmacological tests as stimulation in vitro of lymphocyte growth in murine thymus cells cultured in the presence of concanavalin A (con A), using the general assessment method of v. J. Merluzzi et al. , Journal of Clinical and Experimental Immunology, Volume 22, p. 486

(1975). In this work, four different levels of lymphocyte stimulation assay (LSA) activity were determined for the compounds under consideration, namely those equal to con A alone, those having greater activity than con A but less than levamisole, the selected standard compound in the area; those that have the same activity as levamisole; and those with greater activity than levamisole. Compounds are considered active for present purposes if they are better than concavalin A.

The present invention is illustrated by means of

the following examples.

Example 1 (Intermediate A)

Phenethylamine (479 g, 3.96 mol, Eastman Scintillation Grade) was dissolved in 3500 mL of diethyl 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 off. 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 produced no precipitate. The combined solids were dried in air and sieved over phosphorus pentoxide under vacuum to give 514 g (82%) of phenethylamine hydrochloride, m.p. 216-218°C.

Phenethylamine hydrochloride (257 g, 1.63 mol) and ammonium cyanate (123.6 g, 1.63 mol) were heated to 160°C in 340 mL of 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 g of phenethylamine hydrochloride. The combined solids obtained by the above reaction were stirred in 1.5 L of water and filtered. Recrystallization from isopropyl alcohol gave 261.5 g (45%) of N-phenethylthiourea, m.p. 132-134°C.

Example 2

N-phenethylthiourea (225 g, 1.25 mol) and α-bromoacetophenone (250 g, 1.25 mol, Aldrich Chem. Co.) in 1500 mL of absolute ethanol were heated for 2 1/2 hours at reflux temperature 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 2.5 1 absolute ethanol and heated to reflux. The solvent volume was reduced to 2 1 and the reaction mixture cooled to o°C. This procedure was repeated and after the second recrystallization the solids were collected and dried under vacuum over phosphorus pentoxide, which gave 365 g (81%) of 2-phenethylamino-4-phenylthiazole hydrobromide, m.p. 169-172°C.

Analysis: Calculated for C17H16N2S.HBr: C, 56.50? H, 4.74| N, 7.68

Found: C, 57.36; H, 5.04; N, 7.83.

Example 3

N-phenethylthiourea (140 g, 0.779 mol) and decyl bromide

(225 g, 0.82 mol, Eastman Chem. Co.) in 833 mL of absolute ethanol was heated at reflux for 2 hours under nitrogen, an additional 300 mL of absolute ethanol being added during the reaction. The reaction mixture was cooled to 10°C, the solid filtered off, recrystallized from absolute ethanol and dried over phosphorus pentoxide to give 281 g (83%) of 2-phenethylamino-4,5-diphenylthiazole hydrobromide, m.p. 171-174°C.

Analysis: Calculated for C23H20N2S.HBr: C, 63.14; H, 4.84; N, 6.40

Found: C, 62.62; H, 4.82; N, 6.48.

Example 4

N-phenethylthiourea (2.0 g, 0.011 mol) and α-bromopropiophenone (2.34 g, 0.011 mol, Aldrich chem. Co.) in 10 mL of absolute ethanol were heated to reflux for 90 min under nitrogen. The ethanol was then removed under vacuum, excess ethyl acetate added and the solids filtered off and dried over phosphorus pentoxide. Recrystallization from absolute ethanol gave 2.86 g (70%) of 5-methyl-2-phenethylamino-4-phenylthiazole hydrobromide, m.p. 172-175°C.

Analysis: Calculated for C18H18N2S.HBr: C, 57.59; H, 5.10; N, 7.46

Found: C, 57.67; H, 5.11; N, 7.39.

Example 5

By following the procedures from examples 1 and 2, the hydrohalide salts of the following compounds were prepared:

Example 6 (Intermediate B)

2-phenylamine (30 g, 0.265 mol), Fairfield Chem. 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 off and dried over phosphorus pentoxide to give 26.7 g (61%) of 2-thenylamine hydrochloride,

m.p. 186-190°C.

2-Tenylamine hydrochloride (13.35 g, 0.089 mol) and ammonium thiocyanate (7.4 g, 0.089 mol) in 20 mL of bromobenzene were heated to reflux for 90 minutes. The reaction mixture was cooled and the filtered off solids were washed three times with water. Recrystallization from chloroform and drying over phosphorus pentoxide

gave 5.0 g (33%) of N-thenyl-thiourea, m.p. 99-101°C.

Analysis: Calculated for CgHgN^: C, 41.83j H, 4.68; N, 16,26

Found: C, 41.56; H, 4.58; N, 16.07.

Example 7

N-thenyl-thiourea (2.0 g, 0.0116 mol) and α-bromoacetophenone (2.3 g, 0.0116 mol, Aldrich Chem. Co.) in 15 mL of absolute ethanol were heated to reflux for 90 min under nitrogen. The reaction mixture was cooled and the ethanol removed under vacuum. An oil was formed by dissolving the residue in hot isopropyl alcohol and diluting with diethyl ether. The diethyl ether was decanted, the oil dissolved in a small amount of ethanol and cooled. The resulting solids were filtered off and dried over phosphorus pentoxide, whereby 3.20 g (.78%) of 2-tenylamino-4-phenyl-thiazole hydrobromide was obtained, m.p. 115-118°c.

Analysis: Calculated for C14H12N2S2'HBr: C' 47'58; H' 3'71' N» 7'93

Found: C, 47.75; H, 3.74; N, 7.90.

Example 8

N-thenyl-thiourea (0.80 g, 0.0046 mol) and α-chloro-p-fluoro-acetophenone (0.80 g, 0.0046 mol, Aldrich Chem. Co.) in 11 mL of 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, filtered and vacuum dried over phosphorus pentoxide, whereby 0.848 g (56%) of 2-tenylamino-4-(p-fluorophenyl)-thiazole hydrochloride was obtained, m.p. 184-187°C.

Analysis: Calculated for c14HnN2S2F*HCl: C' 51'45s H' 3'70* N< 8»57

Found: C, 51.41; H, 3.63; N, 8.39.

Example 9

Following the procedures of Examples 7 and 8, the hydrohalide salts of the following compounds were prepared:

Example 10 (Intermediate C)

Furfurylamine (25.0 g, 0.257 mol, <p>faltz & Bauer Co.) was dissolved in 1300 mL of diethyl ether and cooled in an ice bath to 0°C. Dry hydrogen chloride gas was bubbled through the solution until no further precipitation occurred. The solids were filtered off and dried in vacuo over phosphorus pentoxide to give 33.46 g (97%) of furfurylamine hydrochloride, m.p. 147-149°C.

Furfurylamine hydrochloride (33.46 g, 0.250 mol) and ammonium thiocyanate (38.14 g, 0.501 mol) in 71 mL of bromobenzene were heated under nitrogen at reflux for 20 minutes and then cooled to room temperature. The reaction mixture was mixed with a solution of 125 ml of water and 100 ml of ethyl acetate and allowed to stand 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 evaporated to dryness and bromobenzene removed under vacuum. The resulting solids were ground in a mortar and pestle and the fines stirred in diethyl ether to remove residual bromobenzene. The solids were then filtered, washed with diethyl ether and vacuum dried over phosphorus pentoxide to give 12.06 g (30%) of N-furfurylthiourea, m.p. 80-91°c.

Analysis: Calculated for CgHglS^OS: C, 46.14? H, 5.16? N, 17.93

Found: C, 46.91? H, 4.90? N, 17.57.

Example 11

N-furfurylthiourea (0.82 g, 0.005 mol) and α-bromopropiophenone (1.07 g, 0.005 mol, Aldrich Chem. Co.) in 11 mL of absolute ethanol were heated to reflux temperature under nitrogen in

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 approx. 25 ml and cooled to room temperature. The precipitated solids were filtered off, washed with ethyl acetate and vacuum dried over phosphorus pentoxide to give 0.585 g (33%) of 2-furfurylamino-5-methyl-4-phenyl-thiazole hydrobromide, m.p. 150-153°C. Analysis: Calculated for <C1>5<H>14<N>2OS.HBr: C, 51.29; H, 4.30; N, 7.97

Found: C, 51.97; H, 4.47; N, 8.42.

Example 12

Following the procedures of Examples 10 and 11, the hydrohalide salts of the following compounds were prepared:

Example 13 (Intermediate D)

Diphenylmethylamine (25.0 g, 0.136 mol, 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 was added to the mixture. The precipitate was filtered off, washed with diethyl ether and vacuum dried over phosphorus pentoxide to give 28.3 g (95%) of diphenylmethylamine hydrochloride, m.p. 303-310°C (decomposition).

Diphenylmethylamine hydrochloride (28.3 g, 0.129 mol) and ammonium thiocyanate (9.81 g, 0.129 mol) in 37 mL of bromobenzene were heated at reflux under nitrogen for 3 1/2 hours and then cooled to room temperature. The solids were filtered off and triturated twice with 200 ml of water. The solids were then dissolved in 850 ml of ethanol, filtered and evaporated to a volume of approx. 3 50 ml. After cooling, the solids were filtered off, washed with ethanol

and vacuum dried over phosphorus pentoxide to give 14.72 g (56%) of N,N'-bis-(diphenylmethyl)thiourea, m.p. 216-217.5°C.

Analysis: Calculated for C27<H>24<N>2<S:> C, 79.37; H, 5.92; N, 6.86

Found: C, 79.84; H, 6.05; N, 6.93.

Example 14

N,N<1->bis-(diphenylmethyl)thiourea (1.21 g, 0.005 mol) and decyl chloride (1.21 g, 0.005 mol, Aldrich chem. Co.) in 11 mL of absolute ethanol were heated to reflux temperature under nitrogen for 3 hours. After cooling, the reaction mixture was evaporated to dryness, and the resulting oil was mixed with ca. 40 ml of diethyl ether. The solids were filtered off, cooled with diethyl ether and vacuum dried over phosphorus pentoxide to give 1.01 g (75%) of 4,5-diphenyl-2-diphenylmethylamino-thiazole hydrochloride, m.p. 195-198°C. Analysis: Calculated for C2qH22<N>2<S.H>Cl: C, 73.91; H, 5.09; N, 6.16

Found: C, 73.12; H, 5.28; N, 6.06.

Example 15

By following the procedures from examples 13 and 14, 4-phenyl-2-diphenylmethylamino-thiazole hydrobromide was prepared, m.p. 166-168°c.

Example 16 (Intermediate E)

N-Phenylethylenediamine (25 g, 0.184 mol, Aldrich Chem. Co.) was dissolved in diethyl ether, cooled to 0°C and dry hydrogen chloride gas bubbled through the solution until no more precipitate formed. The filtered off solids were dried over phosphorus pentoxide for

to give 31.2 g (98%) of N-phenylethylenediamine hydrochloride.

N-phenylethylenediamine hydrochloride (31.2 g, 0.149 mol) and ammonium thiocyanate (11.3 g, 0.149 mol) in 31 mL of bromobenzene were heated to reflux under nitrogen for 2 hours. After cooling, the resulting solids were filtered off and the bromobenzene removed from the filtrate 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 off and dried over phosphorus pentoxide to give 2.8 g (8%) of N-(2<1->anilino-ethyl)-thiourea, m.p. 13 7-140°C.

Analysis: Calcd for CgH13N3S: C, 55.35; H, 6.71; N, 21.52

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

Example 17

N-(2'-anilinoethyl)-thiourea (0.90 g, 0.0046 mol) and α-bromoacetophenone (0.92 g, 0.0046 mol, Aldrich chem. co.) in 6 mL of absolute ethanol were heated 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 off and dried over phosphorus pentoxide to give 1.25 g (73.5%) of 2-(2'-anilinoethylamino)-4-phenyl-thiazole, m.p. 161-165°C.

Analysis: Calculated for C17H17N3S.HBr: C, 54.24; H, 4.82; N, 11,16

Found: C, 54.51; H, 4.59, N, 11.02.

Example 18

Following the procedures of Examples 16 and 17, the hydrohalide salts of the following compounds were prepared:

The immunoregulatory activity of the aminothiazoles described in Examples 2, 3, 4, 5, 7, 8, 9, 11, 12, 14, 15, 17, 18, 20 and 21 was assessed by determining their ability to stimulate, in vitro, the lymphocyte growth of murine thymus cells which were cultured in the presence of concavalin A (con A) by applying the method of v. J. Merluzzi et al., as essentially described in the journal of clinical and Experimental immunology, vol. 22, p. 486 (1975). The cells were obtained from male c57Bl/6 mice aged 6-8 weeks, purchased from Jackson Laboratories in Bar Harbor, Maine and con A was obtained from Sigma Chemicals in St. Louis, Missouri. Each cell culture (consisting of 0.10 ml stock solution of thymus cells, 0.05 ml con A stock solution and 0.05 ml drug solution) was prepared in four equal parts and cell growth was measured after 48 hours of incubation at 37°C, by pulsing each culture with H-thymidine (0.01 ml with specific activity 1.9 C/mM, obtained from Schwarz-Mann, inc. Orangeburg, N.Y.) and then determining the incorporation of <3>H-thymidine into cellular deoxyribonucleic acid (DNA) with a determination of radioactivity using a liquid spark counter. The results obtained in this way are expressed quantitatively by averaging per minute (cpm)

of H-thymidine incorporated at the drug level that has maximum activity in the four parallel cell cultures. These four parallel determinations are used at eight different drug concentrations in the range 0.02 to 50 µg/ml. The highest achieved cpm value is used in the scoring system. on this basis, four different activity levels were established in the present lymphocyte stimulation experiment (LSA) and these are defined in the manner indicated below, namely that the levels equal to con A alone (6000 in 300 cpm) were given a negative value or score of zero; those better than con A activity but worse than levamisole (10000 700 cpm) were given the value +; while those equal to levamisole (22000 900 cpm) were given the score ++ and those with greater activity than levamisole (27000 1000 cpm) were given the score +++. The LSA activity of the compounds described in the above examples was +++ in each case.

The anti-inflammatory activity of the aminothiazoles of the invention was determined using the carrageenan-induced standard rat foot edema test essentially according to the method described by C. A. Winter et al., Proceedings of the Society for Experimental Biology and Medicine, vol. . 111,

pp. 544 (1962). The compounds were administered orally in the form of the previously mentioned hydrohalide salts in a dosage amount of

33 mg/kg. The results obtained in this way are indicated

in the table below expressed as percent inhibition of edema formation caused by each test compound, compared to the drug-free control sample (i.e., aqueous solution without any compound).

Claims (2)

1. Analogy method for the preparation of a therapeutically active compound of the formula: where R., is • -(CH2)2-X, -CH2-CH2-NH-X or -(CH^Y, where X is phenyl or monosubstituted phenyl, said substituent being alkyl with 1 to 3 carbon atoms, hydroxy, alkoxy with 1 to 3 carbon atoms, chlorine, bromine or fluorine; Y is thienyl, monosubstituted thienyl, furyl or monosubstituted furyl, said substituent being alkyl of 1 to 3 carbon atoms, chlorine, bromine or fluorine; m is 1 or 2; R 2 is phenyl, thienyl or monosubstituted phenyl, said substituent being alkyl with 1 to 3 carbon atoms, hydroxy, alkoxy with 1 to 3 carbon atoms, chlorine, bromine or fluorine; and R-j is hydrogen, alkyl with 1 to 3 carbon atoms, phenyl or monosubstituted phenyl, said substituent being alkyl with 1 to 3 carbon atoms, alkoxy with 1 to 3 carbon atoms, bromine, chlorine or fluorine, characterized in that a suitable substi tuated N-aralkylthiourea with the formula or if desired when R^ is < a bis-substituted N-aralkylthiourea of the formula where R^ and X are as defined previously, is converted to a α-halo-carbonyl compound of the formula R^OCHfZjR^, where R2 and R^ are as defined previously and Z is halogen, and, if desired, converting the compound of formula I into a pharmaceutically acceptable acid addition salt. 2. Process according to claim 1, characterized in that compounds are used in which R 2 is -(CH 2 ) 2 ~ <phenyl>nyl, R 2 is phenyl and R 2 is hydrogen.