ALPHA-PHENYL-2-(AZA)BENZOTHIAZOLYLTHIOGLYCOLIC ACIDS AND DERIVATIVES THEREOF

Abstract: Compounds having the formula I wherein R₁ is hydrogen, halo, nitro, amino, lower alkyl, lower alkoxy, trifluoromethyl or hydroxy R₂ is hydrogen, fluorine, chlorine, bromine, lower alkyl, lower alkoxy, amino, nitro or trifluoromethyl; R₃ is hydroxy, lower alkoxy, amino, hydroxy(lower)alkylamino N-­ (lower)alkanoylamino(lower)alkoxy or N-arylcarbamoyl­ (lower)alkylthio; X is CH or N, and the dotted lines represent optional double bonds in the 5, 6 and 7, 8-positions and their pharmacologically acceptable salts are useful as pharmaceu­ ticals, particularly as immuno modulating agents. Processes for making the compounds having formula I and their pharmacologically acceptable salts are also described. The compounds are new per se, provided that, where R₃ is hydroxy, then R₁ is nitro.

Description: a-PHENYL-9-(AZA)BENZOTHIAZOLYLTHIOGLYCOLIC ACIDS AND DERIVATIVES THEREOF The invention relates to -phenyl-2-(aza)benzo thiazolyithioglycolic acids, derivatives thereof and pharmacologically acceptable salts thereof. The compounds are useful as modulators of the immune response In recent years, the rapid upsurge in immunological research has brought about a greater appreciation and understanding of the complexities of the immune response. While the traditional overall view of the immune system remains, new discoveries have radically changed some thinking about the details of the system. Thus, the immune system is still divided into humoral immunity, populated with B cells and responsible for antibody formation, and cell-mediated immunity, ooDulated with T cells and resoonsible for the rejection of organ transplants or skin grafts, as well as the defence mechanism against various foreign biological matter and endogenous neoplastic growths. It is only in the last decade or so, however, that the concept has been accepted that different cell populations interact in the induction and expression of both humoral and cell-mediated immunity. Thus, subpopulations of B cells and T cells have been described, such as for example "suppressor" and "helper" T cells. In a number of animal models, it has been postulated that the helper T cells act in the induction of a complete antibody response to many antigens, whereas T suppressor cells are capable of preventing or terminating such responses. It is now believed that positive and negative cellular interactions control the ultimate degree of immune response. So, it is believed that any given immune response is regulated, and that the degree and mode of regulation may ultimately explain the various reactions, diseases, and disorders which are the manifestations of the operation of the organism's immune system. The T cell subpopulations of suppressor and helper T cells have been implicated in a number of immune response manifestations. Thus, the loss of suppressor T cells is now believed to be a major factor in such autoimmune connective tissue disease as systemic lupus erythematosus. Moreover, in the latter case, as well as in probable impaired immune system responses such as rheumatoid arthritis, it is believed the helper T cells exacerbate the condition. Also, the theory has been advanced that T suppressor cell hypofunctioning, resulting in inadequate T-B cell cooperation in the immune response, with continuous B cell stimulation and subsequent antibody production may be the cause of the production of antigen-antibody complexes which are the causative agents of renal and inflammatory processes in arthritis and autoimmune diseases. Thus, it is now apparent that a number of lymphopoietic disorders are undoubtedly associated with abnormalities of T cell and especially suppressor cell function. The loss of suppressor function is at least an early event in certain immune response diseases and is a disease-perpetuating mechanism in other. The loss of suppressor function probably leads to excessive lymphoid cell proliferation and may significantly contribute to lymphoproliferative disorders. The conditions created thereby may be exacerbated by helper T cells. The role of immunomodulatory agents in the treatment of immune diseases and disorders, as well as in the attempt to prolong the life of organ transplants and skin grafts, has been to suppress the immune response, especially of cell-mediated immunity. By suppressing the cell-mediated immune response, it is possible to delay and possibly prevent the host organism from rejecting a skin graft or organ transplant, or the graft from immunologically rejecting the host (graft vs. host reaction). Similarly, enhancing or reinstituting suppressor function by immunomodulator therapy is a beneficial course of treatment for autoimmune and probable autoimmune diseases and disorders. Immunotherapy is also being recognised as an important aspect of the treatment, especially chemotherapeutic, of various forms of cancer and metastic diseases. The compounds of the present invention are immunomodulatory agents which are especially indicated in the treatment of various skin graft and organ transplant reactions, neoplastic and metastatic diseases, and immune system diseases and disorders such as systemic lupus erythematosus and rheumatoid arthritis. According to one aspect the invention provides compounds for use as pharmaceuticals particularly for use as immunomodulating agents. The compounds are those having the general formula: EMI3.1 wherein R1 is hydrogen, halo, nitro, amino, lower alkyl, lower alkoxy, trifluoromethyl or hydroxy; R2 is hydrogen, fluorine, chlorine, bromine, lower alkyl,loer alkoxy, amino, nitro or trifluoromethyl; R3 is hydroxy, lower alkoxy, amino, hydroxy(lower) alkyl amino, N-(lower)alkanoylamino(lower)alkoxy or N-arylcarbamoyl(lower)alkylthio; X is CH or N, and where the dotted lines represent optional double bonds in the 5,6 and 7,8 positions, and the pharmacologically acceptable salts thereof. The compounds are new per se subject to the proviso that when R3 is hydroxy then R1 is nitro. According to a second aspect, the invention provides a pharmaceutical composition comprising a compound having the formula I or a pharmacologically acceptable salt thereof in association or combination with a pharmaceutically acceptable carrier. The invention also includes a method of preparing the said composition by bringing the compound having formula I or a pharmacologically acceptable salt thereof into association or combination with a pharmaceutically acceptable carrier. The term "lower alkyl" when used herein includes straight and branched chain hydrocarbon radicals having from 1 to about 6 carbon atoms. The terms "lower alkoxy" and "lower alkanoyl" in like manner designate radicals in which the hydrocarbon portion has 1 to about 6 carbon atoms. The terms "halo" and "halide when used herein refer to radicals of the elements fluorine, chlorine and bromine and chlorine and bromine, respectively. The compounds having the formula I and their salts may be prepared by: (a) reacting a compound having the formula II EMI4.1 (wherein R1, X and the dotted lines are as defined above) or a salt thereof with a compound having formula III EMI5.1 (wherein R2 and R3 are as defined above and Hal is chlorine or bromine) or a salt thereof; or (b) reacting a compound having the formula IV EMI5.2 (wherein R1, R2, X and the dotted lines are as defined above) with a nucleophilic reactant having the formula R3H (where R3 is as defined above); and, if desired, a salt of a compound having formula I is converted into a compound having formula I or a compound having formula I is converted into a pharmacologically acceptable salt thereof. Method (a) is preferably used where compounds having the formula I where R3 is hydroxy and their salts are to be prepared, for instance, according to the following reaction sequence: EMI6.1 wherein R1, R2, X, Hal and the dotted lines are as defined hereinbefore. The reaction of the appropriately substituted 2-mercapto(aza)benzothiazole (II) and the a-halophenylacetic acid (IIIa) may be carried out in an organic solvent, such as for example acetone and can be performed at room temperature or at elevated temperatures. The substituted-2-mercapto(aza) benzothiazoles can be reacted in their alkali metal or alkaline earth metal salt form. The reaction can also be carried out in the presence of a scavenging agent for the liberated hydrohalide, such as a tertiary amine, for example triethylamine. This is preferred in the preparation of the azabenzothiazolylthioglycolic acids. The derivatives of the a-phenyl-2-(aza)-benzothiazolylthioglycolic acids of the invention are most conveniently prepared by reacting the tricyclic mesionic didehydro compounds having formula IV with appropriate nucleophilic reactants. This reaction, involving the ring cleavage of the terminal thiazole ring, is as EMI7.1 wherein R1, R2, R3, and X are as described hereinbefore. The reaction is carried out in a suitable organic solvent, such as for example methylene chloride and over a range of temperatures, such as room temperature as well as under reflux conditions, depending on the nature of the nucleophilic reactant being used. The compounds of formula I may be prepared in the form of acid addition salts, particularly the hydrohalide salt where method (a) is carried out. Such salts may be converted into the compounds having formula I by removing the acid in known manner. The compounds of formula in which R3 is hydroxy may be prepared in the form of the carboxylic acid and the carboxylate salts. The acid and salts are interconvertible in known manner, for instance, neutralisation of the acid with a base yields a salt or addition of an acid to the salt yields the carboxylic acid. The starting materials having formulae 11,111 and IV and the nucleophilic reagent having the formula R3H are generally known and, where new, can be prepared in known manner. The preparation of compounds having the formula IV is described in our European Patent Application Publication No. 21773. The compounds of the invention are immunomodulators. The compounds have therapeutic application in a variety of situations in which immunomodulation is indicated. Thus, the compounds are useful in treating allograft reactions, organ transplant reactions, and graft vs. host reactions. The compounds permit the host to accept the graft without destroying the host's immunity to other infections. The compounds are also useful in the treatment of autoimmune diseases, such as systemic lupus erythematosus (SLE). Further, the compounds of the invention inhibit the production of the immunoglobulins, which are so pathologic to autoimmune disease such as SLE, as well as the production of antigen-antibody complexes which are the causative agents of renal and inflammatory processes in arthritis and autoimmune diseases. Thus, the compounds of the invention are also useful in the treatment of such conditions as rheumatoid arthritis. Moreover, the compounds can be used in the treatment of neoplastic diseases, as well as metastatic diseases. Accordingly, the invention is further directed to a method of modulating the immune response in warmblooded animals in need of modulation of the immune response by administering to a warm-blooded animal an amount effective to bring about said modulation of the immune response of a compound having the general formula I. When the compounds of the invention are employed as immunomodulators, they can be formulated into oral dosage forms such as tablets, capsules and the like. The compounds can be administered alone or by combining them with conventional carriers, such as magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methyl cellulose, sodium carboxymethyl cellulose, low melting wax, cocoa butter, and the like. Diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders, tablet-disintegrating agents and the like may be employed. The compounds may be encapsulated with or without other carriers. In all cases the proportion of active ingredients in said compositions both solid and liquid will be at least sufficient to impart immunomodulatory activity thereto on oral administration. The compounds may also be injected parenterally, in which case they are used in the form of a sterile solution containing other solutes, for example, enough saline or glucose to make the solution isotonic. The dosage requirements vary with the particular compositiors employed, the route of administration, the severity of the symptoms presented and the particular subject being treated. Treatment will generally be initiated with small dosages less than the optimum dose of the compound. Thereafter the dosage is increased until the optimum effect under the circumstances is reached. In general, the compounds of the invention are most desirably administered at a concentration level that will generally afford effective results without causing any harmful or deleterious side effects. With large animals (about 70 kg. body weight), for injection administration the dose may be from about 25 milligrams to about 50 milligrams and for oral administration the dose may be from about S0 milligrams to about 200 milligrams and preferably from about 50 milligrams to about 100 milligrams per day either as a single unit dose, or if desired, the dosage may be divided into convenient subunits administered at convenient times throughout the day. The immunomodulatory effect of the compounds of the invention may be demonstrated by standard pharmacological and histological procedures. The pharmacological procedures are described more fully in the examples given hereinafter. These procedures illustrate the ability of the compounds of the invention to exert an immunomodulatory effect, especially selectively on the cell-mediated immunity by directly measuring the effect of the compounds on the humoral and cell-mediated immunity, and include evaluation of the compounds in the Plescia anti-SRBC antibody production assay and evaluation in the mitogen activated murine T lymphocyte proliferation test. Example 1 a-(2-Benzothiazolylthio)benzeneacetic acid A. a-(2-Benzothiazolylthio)benzene acetic acid, hydrobromide A solution of 16.79 (0.10m) 2-mercaptobenzothiazole and 21.59 (0.10m) a-bromo-a-phenylacetic acid in acetone is heated to reflux for 5 hours and the solvent is then removed. The residual oil is triturated in acetone and 319 of solid collected. The compound melts at 192-40C. Analysis for: C15H11N02S2.HB Calculated: C, 47.12; H,3.17; N, 3.66; Br, 20.90; S, 16.77 Found: C, 47.22; H, 3.06; N, 3.69; wr, 20.93; S, 16.73 B. -(2-BenzothiazoLylthio)benzene acetic acid The hydrobromide salt of A above is stirred in water at room temperature overnight, the solid collected and air dried The crude material is recrystallised from acetonitrile to give the title compound in 70% yield and melting at 152-4OC. Analysis for: C16H11N02S2 Calculated: C, 59.78; H, 3.68; N, 4.65 Found: C, 59.81; H, 3.85; N, 4.77 Example 2 a-(5-Chlorobenzothiazol-2-ylthio) benzene acetic acid 50.09. (0.248m) 5-chloro-2-mercaptobenzothiazole and 53.09 (0.?48m) a-bromophenylacetic acid are dissolved in 1.5 1 acetone and the solution is heated for 4 hours in the presence of 50 ml glacial acetic acid. The solution is concentrated to a smaller volume (about 200 ml) and the residual solid (909) is collected. The resulting salt is suspended in 1 1 of water and the mixture is stirred at room temperature overnight. The collected solid is recrystallised from 2.5 1 acetonitrile to give a total of 649 (85 yield) of title compound melting at 190-2 0C. Analysis for: C15H10ClN02S2 Calculated: C, 53.64; H, 3.00; N, 4.17 Found: C, 53.83; H, 3.13; N, 4.13. Example 3 Sodium salt of a-(5-chlorobenzothiazol-2 ylthio)benzene acetic acid To a solution of 109 (0.03m) of the compound of Example 2 in 600ml of acetone is added an alcoholic NaOH (1.29 (0.03m) in 20ml ethanol) solution. The precipitate is collected and recrystallised from water. 8.09 (711 yield) of title compound is isolated as a monohydrate melting at 238-42sC (dec.). Analysis for: C1SH9C1N02S2Na H20 Calculated: C, 47.93; H, 2*95; N, 3.73 Found: C, 47.7; H, 3.12; N, 3.79. Example 4 a-(5-chlorobenzothiazol-2-ylthio)-a (e-chlorophenyl)acetic acid Method A. An acetone solution of 12.19 (0.06m) 5-chloro2-mercaptobenzothiazole and 15.09 (0.06m) -bromo-a-(p- chlorophenyl)-acetic acid is heated in the presence of 30ml glacial acetic acid for 5 hours. After solvent removal, the residual solid is collected. This solid (99 of the hydrobromic salt of the title compound) is stirred in water overnight and the solid is collected and air dried. The crude material is recrystallised from acetonitrile to give 4.79 (21% yield) of the title compound melting at 157-8 C. Method 0. An acetone solution of the potassium salt of 5-chloro-2-mercaptobenzothiazole (0.05m) and a-bromo-a (p-chlorophenyl)-acetic acid (0.05m) are heated to reflux for 3 days. The solid (KBr), formed during the reaction, is filtered off and the filtrate is concentrated, and the residual solid triturated with a mixture of acetone and hexane. The crude material is recrystallised from benaene to give 7.79 (42% yield) of title compound melting at 157-8OC. Method C. A methylene chloride solution of 10.09 (0.05m) 5-chloro-2-mercaptobenzothiazole, 12.59 (0.05m) a-bromo a-(p-chlorophenyl)-acetic acid and 10.09 (0.10m) triethylamine is heated to reflux overnight. The reaction mixture is washed first with a dilute hydrochloric acid solution, then with water and finally dried over MgS04. After the methylene chloride is removed, the residual solid is triturated with acetonitrile to give 13.69 (74% yield) of title compound melting at 157-8OC. Analysis for: C15H9Cl2N02S2 Calculated: C, 48.65; H, 2.45; N, 3.78 Found: C, 48.69; H, 2.58; N, 3.79 Example 5 a- (p-Chlorophenyl)-a-(benzothiazol-2-yl-thio) acetic acid Following the procedure of Example 4, Method C and substituting 2-mercaptobenzothiazole for 5-chloro-2mercaptobenzothiazole, the title compound is prepared in 34% yield and having a melting point of 186-7 0C (dec.) Analysis for: C 15H10C1N 02S2 Calculated: C, 53.64; H, 3.00; N, 4.17 Found: C, 54.07; H, 3.17; N, 4.13 Example 6 Preparation of 6-Chloro-2-phenylthiazolo [2,3-b]benzothiazol-3(2H)-one mesionic didehydro derivative 319 (0.092m) of the compound of Example 2 is suspended in 3.5 1 methylene chloride and the mixture is heated to gentle reflux in the presence of 25 ml acetic anhydride. The solid is gradually dissolved, the solution turning reddish. After heating overnight, the solution is filtered and concentrated to 200 ml. The residual orange solid, weighing 29.59 (quantitative yield), is collected and has a melting point of 216-6 C. Example 7 a-(5-Chlorobenzothiazol-2-ylthio) benzene acetic acid 79 of the compound of Example 6 is dissolved in 100 ml N,N-dimethylacetamide and the solution is allowed to stand at room temperature for 2 days in the pretence of 5 ml water. The solution is diluted with 120 ml water and the resulting solid is collected and air dried. The crude material is recrystallised from 500 ml benzene. 5.99 (80% yield) of purified title compound is obtained, having a melting point of 190-1 0C. Analysis for: C15H10C1N02S2 Calculated: C, 53.64; H, 3.00; N, 4.17 Found: C, 53.83; H, 3.13; N, 4.13 Example 8 a-(5-Chloro-2-benzothiazolylthio)benzene acetic acid, ethyl ester 8.09 of the compound of Example 6 is dissolved in ethanol and the solution is warmed over a steam bath until the orange colour is discharged. The solvent is removed and oily residue is recrystallised from hexane. 6.69 (73% yield) of title compound is obtained, having a melting point of 62-4 C. Analysis for: C17H14ClN02S2 Calculated: C, 56.11; H, 3.88; N, 3.85 Found: C, 56.05; H, 3.92; N, 3.84. Example 9 a-(5-Chlorobenzothiazol-2-ylthio)-a phenylacetamide To 6.09 (0.189m) of the compound of Example 6 in 300 ml methylene chloride is introduced gaseous ammonia. The orange solid dissolves with'discharge of the orange coloration by the precipitation of a white solid. After 15 minutes, the introduction of ammonia is stopped and the mixture is stirred for 30 minutes. The solid is collected and a further quantity of solid is recovered upon removal of the solvent from the filtrate. The combined solids are recrystallised from acetonitrile to give 5.09 (79% yield) of title compound having a melting point of 181-3 0C. Analysis for: C15H11ClN20S2 Calculated: C, 53.80; H, 3.31; N, 8.37 Found: C, 53.67; H, 3.41; N, 8.44 Example 10 a-[(5-Chloro-2-benzothiazolyl)thio]- N-(2-hydroxyethyl)benzene acetamide 6.29 (0.02m) of the compound of Example 6 and 1.29 (0.02m) ethanolamine in a methylene chloride solution are warmed over a steam bath until dissolution is complete and the colouration discharged. The solution is filtered and the solvent removed. The residue is triturated with ether, the solid is collected and dried in a drying oven. 6.29 (82% yield) of title compound, having a melting point of 148-9 C, is obtained. Analysis for: C17H1sClN202S2 Calculated: C, 53.88; H, 3.99; N, 7.40 Found: C, 54.03; H, 4.14; N, 7.46 Example 11 a-[ (6-Chloro-2-benzothiazolyl)thio] benzene acstic acid, [2-(acetylamino)ethyl]ester 3.189 (0.01m) of the compound of Example 6 and 1.039 (0.01m) N-acetylethanolamine are dissolved in methylene chloride and the solution is heated to reflux for 3 days. After removal of the solvent, the oily residue is recrystallised from 100 ml ether. 3.59 (83% yield) of title compound, having a melting point of 107-80C is obtained. Analysis for: C19H17C1N203S2 Calculated: C, 54.21; H, 4.07; N, 6.66 Found: C, 53.95; H, 4.14; N, 6.59 Example 12 a-[(5-Chloro-2-benzothiazolyl)thio] benzeneethanethioic acid, s-[2-(2-naphthalenylamino)-2 oxoethyl]ester 3.189 (0.01m) of the compound of Example 6 and 2.179 (0.01m) a-mercapto-N-(2-naphthyl) acetamide are dissolved in methylene chloride and the mixture is heated to reflux for 7 days. The progress of the reaction is monitored by TLC. After removal of solvent, the residue is recrystal- lised from ether. 2.39 (42% yield) of title compound, having a melting point of 144-6 0C, is obtained. Analysis for: C27H19ClN202S3 Calculated: C, 60.60; H, 3.58; N, 5.24 Found: C, 60.89; H, 3.78; N, 5.27 Example 13 a-[(5-Chlorothiazolo[5,4-b]pyridin-2-yl)thio] a-phenyl acetic acid A methylene chloride solution of 4.059 (0.02m) 5-chloro-2-mercaptothiazolo[5,4-b]pyridine, 4.309 (0.02m) a-bromophenylacetic acid and 4.09 (0.04m) triethylamine is heated to gentle reflux overnight. The methylene chloride solution is extracted twice with a dilute hydrochloric acid solution and once with water and then dried over anhydrous MgS04. After the solvent is removed, the residual solid is recrystallised from acetonitrile. 5.09 (74% yield) of title compound, melting at 175-7 C, is obtained. Analysis for: C14H9C1N202S2 Calculated: C, 49.92; H, 2.69; N, 8.32 Found: C, 49.97; H, 2.85; N, 8.37. Example 14 a-p(5-Chlorothiazolo[5,4-b]pyridin-2-yl)thio] -a-(p-chlorophenyl) acetic acid A methylene chloride solution of 6.09 (0.03m) of 5-chloro-2-mercaptothiazolo[5,4-b]pyridine, 7.59 (0.03m) a-bromo-a-(g-chlorophenyl) acetic acid and 6.09 (0.06m) triethylamine is heated to gentle reflux overnight. The solution is extracted twice with a dilute hydrochloric acid solution and then once with water. After drying over anhydrous MgS04, the solvent is removed and the residual solid is recrystallised from acetonitrile. 7.59 (68% yield) of title compound, melting at 144-6 C, is obtained. Analysis for: C14H8C12N202S2 Calculated: C, 45.29; H, 2.17; N, 7.55 Found: C, 44.87; H, 2.27; N, 7.59 Example 15 a-Phenyl-a[ (4,6,6; 7-tetrahydrobenzothiazol-2-yl)- thio] acetic acid A methylene chloride solution of 5.139 (0.03m) 2-mercapto-4,5,6,7-tetrahydrobenzothiazole, a-bromophenylacetic acid and 6.09 (0.06m) triethylamine is heated to gentle reflux overnight. The solution is extracted twice with a dilute hydrochloric acid solution, once with water and is then dried over anhydrous MgS04. The residual solid after solvent removal is recrystallised from acetonitrile. 7.09 (77% yield) of title compound, melting at 118-200C, is obtained. Analysis for: C15H15N02S2 Calculated: C15, 58.99; N, 4.95; N, 4.59 Found: C, 59.0 H, 4.94; N, 4.52. Example 16 a-[(6-Nitro-2-benzothiazolyl)thio] benzeneacetic acid A methylene chloride solution of 5.0g (0.0235m) 2-mercapto-6-nitrobentothiazole, 5.29 (0.235m) abromophenylacetic acid and 5.09 (0.05m) triethylamine is heated to gentle reflux overnight. The solution is washed twice with a dilute hydrochloric acid solution and once with water. The solution is dried over anhydrous MgS04 and then concentrated. The residue is recrystallised once from benzene and then from acetonitrile. 1.59 (18% yield) of title compound, having a melting point of 152-50C, is obtained. Analysis for: C15H10N204S2 Calculated: C, 52.01; H, 2.91; N, 8.09 Found: C, 51.72; H, 2.97; N, 8.01 Example 17 The Plescia anti-SRBC (sheep red biood cells) antibody induction assay is a very sensitive test which is used to measure the ability of an immunomodulatory agent to augment or depress SRBC-induced production of SRBCspecific IgM and IgG antibodies. That is,this assay provides specific information regarding the ability of an immunomodulatory agent to induce the entire immune system to provide an enhanced or depressed antibody response to challenge with an antigen, wliich in the assay in SRBC. The effect of potential immunomodulatory compounds on T cells and their various subpopulations, as well as on B cells, can be studied in this assay. The total assay procedure is essentially in three parts. In the first part, antigen-primed splenocytes (spleen cells) are prepared. C57B1/6J male mice are injected intraperitoneally with 107 SRBC (in pyrogenfree isotonic saline). Ten days later, the animals are sacrificed, their spleens excised and a suspensions of spleen cells is prepared therefrom. The suspension is prepared using 1 ml of tissue culture medium (Click medium supplemented with 10% fetal calf serum) per spleen and all suspensions are pooled into a single suspension. The number of viable nucleated spleen cells in the suspension is counted and adjusted to 10 7/my. In the second part, 1 ml of the above suspension ofprimed spleen cells is added to sterile culture tubes to which is added 1 ml of a standard suspension of SRBC (107/ml of tissue culture medium). Stock solutions of compounds to be tested are prepared in tissue culture medium and from this appropriate dilutions are made to cover a range of concentrations. To each culture tube is added 0.1 ml of each compound dilution, while 0.1 ml of medium alone is added to the control tubes. The tubes are capped, mixed and then placed in a humidified -5% C02 incubator at 37 C for 6 days. The tubes are then centrifuged at 1000xg for about 10 minutes to sediment the cells and the supernatants decanted into test tubes. In the third part, 2-fold serial dilutions of the supernatants, from 1/1 to 1/32, are made and 0.1 ml of each dilution is added to individual test tubes. To each tube there is added 0.1 ml of SRBC (109/ml), the tubes are mixed and allowed to stand at room temperature for 15-30 minutes. Then 0.1 ml complement (guinea pig serum diluted to contain a slight excess of complement) is added to each tube, mixed and the tubes are placed in a 37 0C water bath for lysis of SRBC to occur. Only SRBC that have been sensitised by anti-SRBC antibody in tha supernatant will lyse. 2.0 ml of isotonic saline is added to each tube, mixed and centrifuged to sediment -unlysed cells and to recover the supernatant containing hemoglobin from the lysed SRBC. The supernatants' absorbance is measured at 541 nn. Since the per cent of SRBC that is lysed is proportional to the amount of anti-SRBC antibody present in the test cell culture supernatant, and since lysis is measured in terms of the hemoglobin that is released from the lysed SRBC, it is the absorbance of the released hemoglobin that is measured in order to determine the quantity of anti-SRBC antibody present in the supernatant. Because the assay is most precise at the range of 50% lysis of SRBC in the presence of excess complement, the volume of supernatant that produces 50% lysis of SRBC, by definition, contains 1 unit of antibody called a 50% hemolytic unit (H50). One divided by this volume gives the number of H50's per ml of test supernatant. A standard curve of absorbance vs. H50/ml for control supnatant is then prepared, and the concentration of antibody in other test culture supernatants, for each dilution, is determined. The content of anti-SRBC antibody for the various test compounds at their various concentrations shows whether the compound has caused stimulation or suppression of the immune response. The results of this assay for several compounds of the invention are tabulated in Table 1, where the data is presented as H50 units of antibody/ml and % change from control. Table 1 Experiment 1 Compound Quantity Units of 0 Change from (of Example No) pg/ml Antibody Control Example 2 25 30.32 -428 2.5 84.96 -147 Example 4 25 62.3 -200 2.5 124.6 0 Control - 124.9 Experiment 2 Compound Quantity Units of % Change from (of Example No) g/ml Antibody Control Example 4 25 47.53 -348 Example 3 25 48.26 -343 Control 165.4 - The results show that the compounds of the invention have a profound and significant depressive effect on the immune response, an effect which is further substantiated by the results in the mitogen activated murine T lymphocyte proliferation test. Example 18 The mitogen activated murine T lymphocyte proliferation test is used to determine the effects of immunomodulatory agents on the proliferation of murine T cell populations. The test is run to determine whether test compounds will enhance or depress the proliferation of T cells, whose proliferation has been initially stimulated by a mitogen, such as Concanavallin A (Con A). To exclude the possibility that the test compounds act at Con A binding sites, the T cell proliferation can be studied in a system in which the test compounds are incubated with the T cells prior to the addition Con A instead of in a system in which test compounds and Con A are added to the cell cultures concomitantly. The test procedure is as follows: T lymphocytes are isolated from spleens of male CBA/D or NZB mice. Cell homogenates are prepared in Hank's balanced salt solution (HBSS). After removal of larger particles and repeated washing of the cells in HBSS they are suspended in minimum essential medium (MEM) and passed through a glass wool column to remove macrophages. The cells are then incubated on a nylon wool column at 37 0C, 95% air, 6% CO2, for 45 minutes. The non-adherant T lymphocytes are then eluted from the column, counted, and adjusted to 20 X 106 cells/ml.- 50cm1 of cells are cultured (370C, 95% air, 6% air C02) with compound, or compound and mitogen (0.025 Ag/culture of Concanavalin A) for 48 hours before the addition of 0.5 Ci of 3Hthymidine for the last 16 hours of culture. The total volume of the culture system is 200 l. The cells are then harvested on a multiple automatic sample harvester (Mash II), the glass fibre discs placed in 10 ml of xylene base scintillation fluid, and counted for 1 minute in a liquid scintillation counter. The incubation experiments are conducted in two ways: 1) lymphocytes are incubated for 2 hours with test compounds, washed and cultured with different concentrations of Con A; and 2) lymphocytes are incubated for 24 hours with varied amounts of Con A, washed and then cultured with test compounds. The concentration of Con A used is either 0.04 or 0.05 ug/culture. The effects of some compounds of the invention are summarised as follows: A). Sodium salt of a-(5-chlorobenzothiazol-2-ylthio) benzene acetic acid. When the compound is cultured concomitantly with Con A present in the amounts of 0.02; 0.04; 0.06; and 0.08 g/culture, the compound inhibits the Con A induced blastogenesis at concentrations of 0.1, 1.0, 5 and 10 g/culture. When the compound is cultured with lymphocytes prior to addition of 0.04 or 0.05 Ag/culture of Con A, the compound failed to show inhibitory activity. When the compound is cultured with lymphocytes 24 hours after the cells are incubated with 0.04 or 0.05 Wg/culture of Con A, at concentrations of > 2 or 3 Ag/culture the compound showed strong inhibition of lymphocyte blastogenesis. B). -(5-Chlorobenzothiazol-2-ylthio)- -(p-chlorophenyl) acetic acid. When this compound is cultured concomitantly with Con A present in the amounts of 0.02; 0.03; 0.04 and 0/06 Ag/culture, the compound inhibits the Con A induced blastogenesis at concentrations > 2 ug/culture. When the compound is cultured with lymphocytes prior to addition of 0.04 or 0.05 Ag/culture of Con A, the compound shows consistent inhibitory activity at 3 and 5Ag/culture. When the compound is cultured with lymphocytes 24 hours after the cells are incubated with 0.04 or 0.05 Ag/culture of Con A, at concentrations of > 2 or 3Ag/culture the compound showed strong inhibition of blastogenesis. These results clearly demonstrate that the compounds of the invention are strong and consistent inhibitors of T cell proliferation, which has been mitogenically induced. It is also clear that the compounds are able to perturb T lymphocyte blastogenesis when Con A binding sites are occupied, and so the compounds are not in competition with Con A for, cell binding sites.

Claims: CLAIMS 1 A pharmaceutical composition comprising a compound havIng the formula I EMI26.1 wherein R1 is hydrogen, halo, nitro, amino, lower alkyl, lower alkoxy, trifluoromethyl or hydroxy; R2 is hydrogen, fluorine, chlorine, bromine, lower alkyl, lower alkoxy, amino, nitro or trifluoromethyl; R3 is hydroxy, lower alkoxy, amino, hydroxy(lower) alkylamino, N-(lower)alkanoylamino(lower)alkoxy or N-arylcarbamoyl(lower)alkylthio; X is CH or N, and the dotted lines represent optional double bonds in the 5, 6 and 7,8- positions, or a pharma cologically acceptable salt thereof in association or combination with a pharmaceutically acceptable carrier. 2. A composition as claimed in Claim 1, in unit dosage form. 3. A composition as claimed in Claim 1 or 2 in the form of one or more tablets or capsules or in the form of a sterile solution containing other solutes. 4. A composition as claimed in any one of Claims 1 to 3, wherein the compound having formula I is selected from a-(2-benzothiazolylthio)benzene acetic acid; a-(5-chlorobenzothiazol-2-ylthio)benzeneacetic acid; a-(5-chlorobenzothiazol-2-ylthio)-a-(¯-chloro- phenyl)acetic acid; a-(g-chlorophenyl)- -(benzo- thiazol-2-ylthio)acetic acid; a-(5-chloro-2-benzo thiazolylthio)benzene acetic acid, ethyl ester; a- ( 5-chlorobenzothiazol-2-ylthio) -a-phenylacetamide; a-[(5-chloro-2-benzothiazolyl)thiol-N-(2-hydroxyethyl)- benzene-acetamide; a-[(5-chloro-2-benzothiazolyl)thio] benzene acetic acid,[2-(acetylamino)ethyl]ester; a-[(5-chloro-2-benzothiazolyl)thio]benzeneethanethioic acid,S-[2-(2-naphthalenylamino)-2-oxoethyl]ester; a-[(5-chlorothiazolo[5,4-¯]pyridin-2-yl)thio]-a- phenylacetic acid; a-[5-chlorothiazolo[5,4-b]pyridin- 2-yl)thio]-a-(p-chlorophenylEacetic acid; a-phenyl -[(4,5,6,7-tetrahydrobenzothiazol-2-yl)thio]acetic acid and a- [ (6-nitro-2-benzothiazolyl)thio]benzene- acetic acid. 5. For use as an immunomodulating agent, a compound have EMI27.1 (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1) or a pharmacologically acceptable salt thereof. 6. A compound as claimed in Claim 5, which is selected from a-(2-benzothiazolylthio)benzene acetic acid; a-(5-chlorobenzothiazol-2-ylthio)benzene acetic acid; a-(5-chlorobenzothiazol-2-ylthio)-a-(p-chlorophenyl) acetic acid; a-(¯-chlorophenyl)-a-(benzothiazol-2- ylthio)acetic acid; a-[(5-chlorothiazolof5 4-b] pyridin-2-yl)thio]-a-phenylacetic acid; a- (5-chloro- thiazolo[5,4-b]pyridin-2-yl)thio-a-(-chlorophenyl) acetic acid; a-phenyl-a-[(4,5,6,7-tetrahydrobenzo thiazol-2-yl)thio]acetic acid and the pharmacologically acceptable salts thereof. 7. A compound having the formula I EMI28.1 or a pharmacologically acceptable salt thereof, wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1 subject to the proviso that, where R3 is hydroxy, then R1 is nitro. 8. A compound selected from a-[(6-nitro-2-benzothiazolyl) thio]-benzeneacetic acid and the pharmacologically acceptable salts thereof; a-[(5-chloro-2-benzo thiazolyl)thio]benzene ethanethioic acid,S-[2-(2 naphthalenylamino)-2-oxoethyl]ester; a-[(5-chloro- 2-benzothiazolyl)thio]benzeneacetic acid,[2-(acetyl amino)ethyl]ester; a-[(5-chloro-2-benzothiazolyl)- thio] -N- (2-hydroxyethyl )benzeneacetamide; and a- ( 5-chloro-2-benzothiazolylthio ) benzeneacetic acid, ethyl ester. 9. a-(5-Chlorobenzothiazol-2-ylthio)-a-phenylacetamide. 10. A process for the preparation of a compound having the formula: EMI29.1 (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1) or a pharmacologically acceptable salt thereof, which comprises (a) reacting a compound having the formula II EMI29.2 (wherein R1, X and the dotted lines are as defined in Claim 1) or a salt thereof with a compound having the formula EMI29.3 (wherein Hal is chlorine or bromine and R2 and R3 are as defined in Claim 1 subject to the proviso that, where R3 is hydroxy, then R1 in formula II is nitro) or a salt thereof; or (b) reacting a compound having the formula IV EMI30.1 with a compound having the formula R3H (wherein Rl, R2, R3, X and the dotted lines are as defined in Claim 1). CLAIMS FOR AUSTRIA 1. A process for the preparation of a pharmaceutical composition, comprising bringing a compound having the formula EMI31.1 (wherein R1 is hydrogen, halo, nitro, amino, lower alkyl, lower alkoxy, trifluoromethyl or hydroxy; R2 is hydrogen, fluorine, chlorine, bromin'e, lower alkyl, lower alkoxy, amino, nitro or trifluoro methyl; R3 is hydroxy, lower alkoxy, amino, hydroxy (lower)alkylamino, N-(lower)alkanoylamino( lower)- alkoxy or N-arylcarbamoyl(lower)alkylthio; X is CH or N, and the dotted lines represent optional double bonds in the 5, 6 and 7, 8-positions) or a pharma cologically acceptable salt thereof into association or combination with a pharmaceutically acceptable carrier. 2. A process for the preparation of a pharmaceutical composition, which comprises preparing a compound having the formula EMI31.2 (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1) or a pharmacologically acceptable salt thereof, by (a) reacting a compound having the formula II EMI32.1 (wherein R1, X and the dotted lines are as defined in Claim 1) or a salt thereof with a compound having the formula EMI32.2 (wherein Hal is chlorine or bromine and R2 and R3 are as defined in Claim 1) or a salt thereof; or (b) reacting a compound having the formula IV EMI32.3 with a compound having the formula R3H (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1); and bringing the compound having formula I or a pharmaceutically acceptable salt thereof so prepared into association or combination with a pharmaceutically acceptable carrier.. 3. A process as claimed in Claim 1 or 2, wherein the composition is prepared in the form of a tablet or capsule or in the form of a sterile solution containing other solutes. 4. A process as claimed in any one of Claims 1 to 3, wherein the composition is prepared in unit dosage form. 5. A process as claimed in any one of Claims 1 to 4, wherein the compound having formula I is selected from a-(2-benzothiazolylthio)benzene acetic acid; a-(5-chlorobenzothiazol-2-ylthio)benzeneacetic acid; a-(5-chlorobenzothiazol-2-ylthio)-a-(g-chlorophenyl)- acetic acid; a-(E-chlorophenyl)-a-(benzothiazol-2 ylthio)acetic acud; a-(5-chloro-2-benzothiazolylthio)- benzene acetic acid, ethyl ester; a-(5-chlorobenzo thiazol-2-ylthio) -a-phenylacetamide; a-[(5-chloro- 2-benzothiazolyl)thio] -N- (2-hydroxyethyl)benzene- acetamide; a-[(5-chloro-2-benzothiazolyl)thio]- benzene acetic acid,[2-(acetylamino)ethyl]ester; a-[(5-chloro-2-benzothiazolyl)thio]benzene- ethanethioic acid,S-[2-(2-naphthalenylamino)-2 oxoethyljester; a-[(5-chlorothiazolo[5,4-]pyridin- 2-yl)thio] -a-phenylacetic acid; a-[5-chlorothiazolo [5:4-b]pyridin-2-yl)thio]-a-(p-chlorophenyl)acetic acid; a-phenyl-a-[(4,5,6,7-tetrahydrobenzothiazol- 2-yl)thio]acetic acid and a-[(6-nitro-2-benzothiazolyl) thio]benzene acetic acid. 6. A process as claimed in any one of Claims 1 to 4, wherein if R3 is hydroxy, then R1 is nitro. 7. A process for the preparation of a compound having the formula EMI33.1 (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1) or a pharmacologically acceptable salt thereof for use as an immunomodulating agent, which comprises (a) reacting a compound having the formula II EMI34.1 (wherein R1, X and the dotted lines are as defined in Claim 1) or a salt thereof with a compound having the formula EMI34.2 (wherein Hal is chlorine or bromine and R2 and R3 are as defined in Claim 1 or a salt thereof; or (b) reacting a compound having the formula IV EMI34.3 with a compound having the formula R3H (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1). 8. A process for the preparation of a compound having the formula EMI35.1 (wherein R1, R2, R3, X and the dotted lines are as defined in Claim 1) or a pharmacologically acceptable salt thereof, which comprises (a) reacting a compound having the formula II EMI35.2 (wherein R1, X and the dotted lines are as defined in Claim 1) or a salt thereof with a compound having the formula EMI35.3 (wherein Hal is chlorine or bromine and R2 and R3 are as defined in Claim 1, subject to the proviso that, where R3 is hydroxy, then R1 in formula II is nitro) or a salt thereof; or (b) reacting a compound having the formula IV EMI35.4 with a compound having the formula R3H (wherein Rl, R2, R3, X and the dotted lines are as defined in Claim 1). 9. A process as claimed in Claim 7 or 8, wherein the compound having formula I is selected from (a-(2-benzothiazolylthio)benzene acetic acid; a-(5-chlorobenzothiazol-2-ylthio)benzene acetic acid; a-(5-chlorobenzothiazol-2-ylthio)-a-(p-chlorophenyl) acetic acid; &alpha;-(p-chlorophenyl)-&alpha;- (benzothiazol-2- ylthio)acetic acid; a-(5-chloro-2-benzothiazolylthio) benzene acetic acid, ethyl ester; a-(5-chlorobenzo thiazol-2-ylthio)-a-phenylacetamide; a- [ (5-chloro-2- benzothiazolyl) thiol-N- (2-hydroxyethyl ) benzene- acetamide; &alpha;- [(5-chloro-2-benzothiazolyl)thio] - benzene acetic acid,[2-(acetylamino)ethyl]ester; &alpha;- [(5-chloro-2-benzothiazolyl)thio]benzeneethanethioic acid,S-[2-(2-naphthalenylamino)-2-oxoethyl]ester; &alpha;-[(5-chlorothiazolo[5,4-b]pyridin-2-yl)thio]-&alpha;- phenylacetic acid; a-[5-chlorothiazolo[5,4-b]pyridin 2- yl)thio]-&alpha;- (p-chlorophenyl) acetic acid; a-phenyl &alpha;-[(4,5,6,7-tetrahydrobenzothiazol-2-yl)thio]acetic acid; and &alpha;-[( 6-nitro-2-benzothiazolyl-)thiol]benzene acetic acid. 10. A process as claimed in any one of Claims 7 to 9, wherein, if R3 is hydroxy, then R1 is nitro.

Inventors: GREGORY, FRANCIS JOSEPH, WEI, PETER HSING-LIEN
Applicants: AMERICAN HOME PRODUCTS CORPORATION
Application year: 1982
Main classification: C07D277
IPC codes: C07D277, C07D513