IL109651A - 2-(3h)- Iminothiazoel derivatives - Google Patents

Description

109651/2 71TN>rmWN-(H3)-2 ΠΤ771Π 2-(3H)-Iminothiazole derivatives JANSSEN PHARMACEUTICAL N.V.

C: 93002/4 Background of the invention — In U.S. 3,274,209 there are described 6-aryl-2,3,5,6-teDrahydroirnidazo[2,l-b]thiazole derivatives as anthelminrics. The use of 2 ,5,6-teti^ydro-6-phenylimidazo[2,l-b]- thiazole in aiding the regression of neoplastic disease is described in U.S. 4,584,305.

The immunostimulating properties of (S)-(-)-2,3,5,6-tetrahydro-6-phenylimidazo- [2,l-b]thiazole, generically known as levamisole, were described in Immunopharma- cology L 245-254 (1979), Clin. exp. Immunol., 22, 486-492 (1975) and the references cited therein. The compound 5,6-dihydro-3,5,6-triphenylimidazo[2,l-b]thiazole is described in Gazz. Chim. Ital., H4, 201-204 (1984) [CA ; 101 : 211027f] and the compound 5,6^dihydro-6-phenylirrddazo[2,l-b]thiazole-3-acetic acid ethyl ester, dihydxochloride in J. Heterocycl. Chem., 12, 343-348 (1982). Neither compound appears to have any useful pharmacological or other properties.

The compounds of the present invention differ from the prior art by the fact that the 2,3-bond is unsaturated and that either the 2 and/or the 3-position are substituted.

Further, the present compounds are unexpectedly far more potent immunostimulating drugs than the prior-art compound levamisole.

Description of the invention The present invention which is divided out from Israel Patent No. 96435 is concerned with novel compounds having the formula a pharmaceutically acceptable acid addition salt thereof or a stereochemically isomeric form thereof, wherein X may be CHOH or C=0; Ar is phenyl optionally substituted with from 1 to 3 substituents each independently selected from halo, hydroxy, C1.6alkyloxy, mercapto, Q^alkylthio, C^aUcyl, nitro, amino, mono- and di(C1.6alkyl)amino, Cj^alkylcarbonylamino, arylcarbonylamino, C1.6alkylsulfonylamino, trifluoromethyl, cyano, aminocarbonyl, mono- and • diiQ^alky^aminocarbonyl, hydroxycarbonyl, C1.6alkyloxycarbonyl, formyl and hydroxymethyl; pyridinyl; thienyl; furanyl or furanyl substituted with either C^alkyl or halo; R1 and R2 each independentiy are C1-20alkyl, (C3.7cycloalkyl)C1.6alkyl, C3.7cycloalkyl, aryl or (ary^C^alkyl; and one of R1 and R2 may also be hydrogen; or R1 and R2 taken together may also form a C3.6alkanediyl radical; each aryl independently is phenyl optionally substituted with from 1 to 3 substituents each independently selected from halo, hydroxy, .ealkyloxy, C^alkyl, nitro, amino, trifluoromethyl or cyano, _ provided that when X is C=0, R2 is other than hydrogen when Ar is phenyl, methoxyphenyl, 4-fluorophenyl or 2-thienyl, and R1 is methyl, ethyl or phenylmethyl; and R2 is other than phenyl, methyl and phenylmethyl when Ar is phenyl, 4-halophenyl, 4-nitrophenyl or methoxyphenyl, and R1 is hydrogen or phenyl.

In the foregoing definitions Chalky! defines straight and branch chained saturated hydrocarbon radicals having from 1 to 6 carbon atoms such as, for example, methyl, ethyl, propyl, 1-methylethyl, butyl, l-mechylpropyl, 2-methylpropyl, 1,1 -dimethyl-ethyl, pentyl, hexyl and the like; C^O3^ defines C^galkyl and the higher homologs thereof having from 7 to 20 carbon atoms such as, for example, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl and the branched isomers thereof; C3_7c cloalkyl defines cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl; C3_6alkanediyl defines bivalent straight and branch chained hydrocarbon radicals having from 3 to 6 carbon atoms such as, for example, 1,3-propanediyl, 1,4-butanediyl, 1,5-pentanediyl, 1,6-hexanediyl and the like; halo defines fluoro, chloro, bromo and iodo.

The present invention is also concerned with compounds having the formula and compounds having the formula a pharmaceutically acceptable acid addition salt thereof or a stereochemically isomeric form thereof, wherein Ar, R1 and R2 are as defined above^. . provided that R2 is other than hydrogen when Ar is phenyl, methoxyphenyl, 4-fluorophenyl or 2-thienyl, and R1 is methyl, ethyl or phenylmethyl; and R2 is other than phenyl, methyl and phenylmethyl when Ar is phenyl, 4-halophenyl, ^nitrophenyl or methoxyphenyl, and R1 is hydrogen or phenyl.

The compounds of formula (II) can generally be prepared from the intermediate ketones of formula (VIII) by reduction. (vm) · ® Said reduction can conveniently be carried out by treating the intermediate ketone (VHI) in an appropriate reaction-inert solvent with a reducing agent such as, for example, an alkali metal borohydride, e.g. lithium, potassium or, preferably, sodium borohydride, sodium cyanoborohydride, sodium rri(l-methyipropyl)borohydride, sodium triethyl- borohydride, sodium nimethoxyborohydride, sodium bis(2-me±oxyemoxy)aIuminum hydride, lithium aluminum hydride, li±ium trialkoxyalanes and the like reducing reagents. Appropriate solvents are, for example, water, alkanols, e.g. methanol, ethanol, 1-propanol, 2-propanol and the like, ethers, e.g. Ι,Γ-oxybisethane, tetrahydro-furan, 1,4-dioxane, 2-methoxyethanol, 2,2'-oxybispropane, 1,2-dimethoxyethane, l,l'-oxybis(2-methoxyethane) and the like, aromatic hydrocarbons, e.g. benzene, methylbenzene, dimethylbenzene and the like, or mixtures of such solvents.

Alternatively, the com ound^ of formula (Π) may also be obtained by reacting an epoxide of formula (DC) with a thiazolamine of formula (X).

(IX) (X) Said reaction may conveniently be conducted by stirring and optionally heating the reactants in a reaction-inert solvent optionally in the presence of an appropriate acid. A suitable reaction-inert solvent is an aromatic hydrocarbon, e.g. benzene, methylbenzene and the like, a halogenated hydrocarbon, e.g. dichloromethane, trichloromethane, tetrachloromethane and the like; an ether, e.g. Ι,Γ-oxybisethane, tetrahydrofuran, 1,4-dioxane and the like, a dipolar aprotic solvent, e.g. iiH-diniethylacetamide, dimethylsulfoxide, acetonitnle and the like or a mixture of such solvents. Appropriate acids are organic acids like 4-methylbenzenesulfonic acid, methanesulfonic acid and the like.

The intermediates of formula (VIH) can be obtained by M-alkylating a thiazolamine of formula (X) with a reagent of formula (XI) wherein W is a reactive leaving group as defined hereinabove.

(XI) Said H-alkylation reaction can be carried out by stirring and optionally heating the reactants in a reaction-inert solvent. As examples of reaction-inert solvents there may be mentioned alkanols, e.g. methanol, ethanol, 2-propanol, 1-butanol and the like; ketones, e.g. 2-propanone,*4-methyl-2-pentanone and the like; aromatic hydrocarbons, e.g. benzene, methylbenzene and the like, halogenated hydrocarbons, e.g. dichloromethane, trichloromethane, tetrachloromethane and the like; ethers, e.g. l,l'-oxybisethane, tetrahydrofuran, 1,4-dioxane and the like, esters, e.g. ethyl acetate and the like, dipolar aprotic solvents, e.g. N>N-dime ylfonriamide, li i-dimethylacetamide, dimethyl- sulfoxide, acetonitrile and the like or mixtures of such solvents. In some^nstances, the addition of an alkali metal iodide such as, for example, potassium iodide and the like may be appropriate.

The intermediates of formula (TV) can be obtained by cyclizing a diamine of formula (ΧΓΓ) with a reagent of formula L-C(=S)-L (ΧΠΓ) wherein L represents an appropriate leaving group. (ΧΠ) (xm) (rv) As typical examples of the reagents of formula (XIII) there may be mentioned thiourea, carbonothioic dichloride, 1, l'-carbonothioylbis-[1H-imidazole] and the like reagents. Carbon disulfide can also be used to perform the cyclization reaction.

Said cyclization reaction may conveniently be conducted by stirring and optionally heating the reactants in a reaction-inert solvent such as, for example, an aromatic hydrocarbon, e.g. benzene, methylbenzene, dimethylbenzene and the like; a halogenated hydrocarbon, e.g. trichloromethane, tetrachloromethane, chlorobenzene and the like; an ether, e.g. Ι,Ι'-oxybisethane, tetrahydrofiiran, 1,4-dioxane and the like; a dipolar aprotic solvent, e.g. HJi-dimethylformamide, dimethylsulfoxide, l-methyl-2-pyrrolidinone, pyridine, methyipyridine, tiraethylpyridine, terrahydro-thiophene 1,1-dioxide and the like; or a mixture of such solvents. In some instances however, it may be preferable to heat the reactants without a solvent. Further, it may be appropriate to add to the reaction mixture a base such as, for example, an amine, e.g. ii-(l-methylemyl)-2-propanamine, 4-methylmorpholine and the like amines. When the reagent- ■ ':is carbon disulfide, the reaction may also be conducted conveniently in water or an alkanol such as, for example, methanol, ethanoi, propanol and the like, in the presence of a base such as for example, sodium hydroxide, potassium hydroxide and the like. Or alternatively, the latter reaction may also be conducted in a basic solvent such as, for example, pyridine and the like, in the presence of a phosphite such as, for example, diphenylphos hite.

The intermediates of formula (ΧΠ) generally can be prepared and resolved following the procedures described in Ann. Chem., 49j4, 143 (1932), incorporated hereinwith by reference. Alternatively, the diamines of formula (ΧΠ) may also be obtained by reacting an appropriately substituted aldehyde Ar-CHO with an alkali metal cyanide, e.g. sodium or potassium cyanide and the like, in the presence of ammonia or an acid addition salt form thereof such as ammonium hydrochloride and the like. The thus obtained aminonitrile may be reduced to a diamine (ΧΠ) following art-known reduction procedures such as, for example, catalytic hydrogenation with palladium-on-charcoal, platinum-on-charcoal, Raney nickel and the like, in a suitable solvent such as, for example, an alkanol, e.g. methanol, ethanol, 2-propanol and the like, an ether, e.g. Ι,Γ-oxybisethane, 2,2'-oxybispropane, tetrahydrofuran, 1,4-dioxane, an aromatic hydrocarbon, e.g. benzene, methylbenzene and the like, in the presence of a suitable acid such as, for example, hydrochloric acid, hydrobromic acid, acetic acid and the like.

The intermediates of formula (X) in turn can be obtained by reacting an intermediate of formula (V) with thiourea (XTV).

Said reaction can conveniently be conducted following the procedure described in Israel Patent 96435 for the preparation of the compounds of formula (i) from the intermediates (IV) and (V) .

Alternatively, the intermediates of formula (X) may also be obtained by reacting intermediate (VII) with thiourea (XTV) and subsequently cyclizing the thus prepared intermediate (XV) with an appropriate acid as described hereinabove for the preparation of the compounds of formula (I) from intermediates (TV) and (VU).

(VU) (XIV) (XV) Pure stereochemically isomeric forms of the compounds of formula (I) may be obtained by the application of art-known procedures. Diastereoisomers may be separated by physical separation methods such as selective crystallization and chromatographic techniques, e.g., counter current distribution, liquid chromatography and the like; and enantiomers may be separated from each other by the selective crystallization of their diastereomeric salts with optically active acids or preferably by chromatographic techniques, e.g. by liquid chromatography using a chiral stationary phase such as suitably derivatized cellulose, for example, tri(dimethylcarbamoyI)cellulose (Chiracel OD®) and the like. Pure stereochemical^ isomeric forms may also be derived from the corresponding pure stereochemically isomeric forms of the appropriate starting materials, provided that the reaction occurs stereospecifically.

Quite unexpectedly the present compounds are far more potent immunostimulating agents than the prior art compound (S)-(-)-2,3,5,6-tetrahydro-6-phenylimidazo[2,l-b]-thiazole which is disclosed in U.S. Pat. Nos. 3,274,209 and 4,584,305 and is generically known as levamisole. The superior irnmunosrimulating properties of the present compounds can clearly be demonstrated by measuring the increased ¾-mymidine incorporation in Concanavalin A-stimulated murine thymocytes in the presence of micromolar amounts of the present compounds. Whereas (S)-(-)-2,3,5,6-terrahydix 6-phenylimida2o[2,l-b]thiazole (levamisole) displays its maximal costimulatory effect only at about 100 uM (Immunopharmacology i, 246 ( 1979) : " ... incorporation of ¾-toyniidine is maximal in the concentration of range of 50 μξ/τήί (~200 μΜ))", the present compounds exhibit maximal costimulatory effects at concentration ranges from about 0.1 to about 1 uM. The present compounds are thus found to be active at concentration ranges a 100 to a 1000 times lower than that of the prior art compound.

Surprisingly, the compounds - of formula (Π) and (VIII) ....... have immunostimulating properties as can be demonstrated by the above described test procedure.

In view of their improved immunostimulating properties, the compounds of formula (I) and the intermediates of formula (Π) and (VET) are taught to be useful in the treatment of humans and warm-blooded animals suffering from disorders and/or diseases wherein the immune system is impaired or suppressed. Typical examples of such disorders and/or diseases comprise, for example, bacterial infections, viral infections, e.g. verrucae, herpes simplex, viral hepatitis, AIDS and the like, tuberculosis, rheumatic disorders and the like. A particularly interesting use of the present compounds comprises their use as adjuvants in antineoplastic therapy. Said use may comprise treatment of the patient with a compound of formula (ii) or (viII)' concomitant with antineoplastic therapy, as well as treatment of patients at risk of recurrent disease after having undergone antineoplastic therapy. The term antineoplastic therapy defines the methods commonly used to treat subjects suffering from malignant diseases such as, for example, surgery, radiotherapy and in particular chemotherapy.

In view of their useful pharmacological properties, the subject compounds and intermediates may be formulated into various pharmaceutical forms for administration purposes. To prepare the pharmaceutical compositions of this invention, an effective amount of the particular compound or intermediate, in acid addition salt or base form, as the active ingredient is combined in intimate admixture with a pharmaceutically acceptable carrier, which may take a wide variety of forms depending on the form of preparation desired for aciministration. These pharmaceutical compositions are desirably in unitary dosage form suitable, preferably, for administration orally, rectally, percutaneously, or by parenteral injection. For example, in preparing the compositions in oral dosage form, any of the usual pharmaceutical media may be employed, such as, for example, water, glycols, oils, alcohols and the like in the case of oral liquid preparations such as suspensions, syrups, elixirs and solutions; or solid carriers such as starches, sugars, kaolin, lubricants, binders, disintegrating agents and the like in the case of powders, pills, capsules and tablets. Because of their ease in administration, tablets and capsules represent the most advantageous oral dosage unit form, in which case solid pharmaceutical carriers are obviously employed. For parenteral compositions, the carrier will usually comprise sterile water, at least in large part, though other ingredients, for example, to aid solubility, may be included. Injectable solutions, for example, may be prepared in which the carrier comprises saline solution, glucose solution or a mixture of saline and glucose solution. Injectable suspensions may also be prepared in which case appropriate liquid carriers, suspending agents and the like may be employed. In the compositions suitable for percutaneous administration, the carrier optionally comprises a penetration enhancing agent and/or a suitable wettable agent, optionally combined with suitable additives of any nature in minor proportions, which additives do not cause any significant deleterious effects on the skin. Said additives may facilitate the adininistration to the skin and/or may be helpful for preparing the desired compositions. These compositions may be administered in various ways, e.g., as a transdermal patch, as a spot-on or as an ointment. Acid addition salts of (n) and (viii) due to their increased water solubility over the corresponding base form, are obviously more suitable in the preparation of aqueous compositions.

It is especially advantageous to formulate the aforementioned pharmaceutical compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used in the specification and claims herein refers to physically discrete units suitable as unitary dosages, each unit containing a predetermined quantity of active ingredient calculated to produce the desired therapeutic effect, in association with the required pharmaceutical carrier. Examples of such dosage unit forms are tablets (including scored or coated tablets), capsules, pills, powder packets, wafers, injectable solutions or suspensions, teaspoonfuls, tablespoon fuls and the like, and segregated multiples thereof. The amount of active ingredient per dosage unit may range from 0.1 to 500 mg, particularly from 0.5 to 100 mg and preferably from 2 to 40 mg.

Those of skill in treating subjects suffering from disorders and/or diseases wherein the immune system is impaired, could easil determine the effective immuno- stimulating amount of the compounds of formula (ii) and (VIII) from the test results presented hereinafter. In general it is contemplated that an effective daily dose of a compound of formula (II) or (Vl-ll) ~ would be from Q.01 mg/kg to 5 mg/kg body weight, preferably from 0.04 mg/kg to 2.5 mg/kg body weight per day. It may be appropriate to administer the required dose as a single dose or divided as two, three, four or more sub-doses at appropriate intervals throughout the day. Said sub-doses may be formulated as unit dosage forms. It is evident that said effective daily dose depends on the condition, the response of the treated subject, the severity of the disorder and/or disease and the evaluation of the physician prescribing the compounds of the instant invention, and that said effective amount may be lowered or increased accordingly.

The effective amount ranges mentioned hereinabove are therefore guidelines only and are not intended to limit the scope nor the use of the present invention to any limit.

An effective immunostimulating amount of a compound of formula (II) or (VIII) can be administered concomitantly with antineoplastic therapy such as, for example, surgery, radiotherapy and in particular chemotherapy. As examples of antineoplastic drugs which may be used in chemotherapy according to the present method, there may be mentioned ancitabine (cycloxytidine), azathioprine, bleomycins, busulfan, calusterone, carboquone, carmustine, chlorambucil, cisplatin, cyclophosphamide, cytarabine, dacarbazine, dactinomycin, doxorubicin (adriamycin), dromostanolone propionate, epitiostanol (epithioadrostanol), estramustine phosphate, etoposide, fluorouracil, diethylstilbestrol diphosphate, hydroxyurea, lomustine, melengestrol, melphalan, 6-mercaptopurine, methotrexate, mitobronitol, mitomycin C, mitopodozide, mitotane, mycophenolic acid, nimustine, pipobroman, piposulfan, prednimustine, procarbazine, razoxane, tegafur, teniposide, testolactone, triethylenethio- phosphoramide, thioguanine, triazequone, trophosphamide, uramusrine, vinblastine, vincristine, vindesine and the like antineo-plastic drugs.

According to the present method an effective antineoplastic amount of an antineoplastic drug, in particular of one or more of the drugs specifically mentioned hereinabove, is administered to the subject to be treated, simultaneously, separately, or sequentially with an effective immunostimulating amount of a compound of formula . (Π) or (Vm). In general it is contemplated that an effective dose of the antineoplastic drug would be such as used commonly in antineoplastic therapy, and the effective inimunostimulating amount of a compound of formula - - — - (II) or (Vni) would range from 0.01 mg/kg to 5 mg/kg body weight per day, preferably from 0.04 mg kg to 2.5 mg kg.

Said method further also comprises treating patients at risk of recurrent disease after having undergone antineoplastic therapy with an effective immunostimulating amount of a compound of formula (ii) or The following may contain subject matter not within the scope of the claims, and which is retained herein, for the sake of completeness of the description.

The following examples are intended to illustrate and not to limit the scope of the present invention. Unless otherwise stated all parts therein are by weight Experimental Part A. Preparation of the intermediates.

Example 1 a) .To a stirred solution of 21 parts of octadecanal in 65 parts of dichlororaethane and 50 parts of 1,4-dioxane there were added dropwise 34.1 parts of bromine. After stirring for 4 hours at room temperature, the reaction mixture was poured into 250 parts of water.

The product was extracted with dichloromethane and the extract was dried, filtered and evaporated, yielding 28 parts (95%) of 2-bromooctadecanal (interm. 1). b) A mixture of 6.7 pans of thiourea, 28 parts of intermediate 1 and 80 parts of ethanol was stirred for 1 hour at reflux temperature. The reaction mixture was evaporated and the residue was washed with NaOH (aq.). The product was extracted with dichloromethane and the extract was dried, filtered and evaporated, yielding 11.8 parts (45%) of 5-hexa-decyl-2-thiazolarnine (interm. 2), Example 2 A mixture of 6 parts of 5-heptyl-2-toiazolamine (prepared as intermediate 2), 6 parts of 2-bromo-l-phenylethanone and 120 parts of acetonitrile was stirred overnight at room temperature. The precipitate was filtered off, washed with 2,2,-oxybispropane and dried, yielding 10 parts of 2-(5-heptyl-2,3-dihydro-2-iniino-3-thiazolyl)-l-phenylethanone hydrobromide (interm. 3).

Example 3 To a stirred and cooled (ice-bath) mixture of 10 parts of intermediate 3 in 120 parts of methanol there was added portionwise 1 part of sodium tetrahydroborate. After stirring for 2 hours at room temperature, the reaction mixture was diluted with 100 parts of water and the whole was evaporated. The residue was triturated in water, filtered off and dissolved in trichloromethane. This solution was dried, filtered and evaporated. The residue was crystallized from 2-propanol, yielding 5.3 parts of 5-heptyl-2,3-dihydro-2-imino-a-phenyl-3-thiazoleethanol; mp. 123.5°C (interm. 4).

The intermediates listed in Tables 1 and 2 were prepared in a similar way.

Table 1 Interm. R - Rl R2 Physical data no. 5 4-Cl CH3 CH3 152.2°C 6 4-Br C2H5 H 166. l°c 7 H CH3 CH3 140.5°C 8 4-Cl CH3 C2H5 143.5°C 9 3-Br CH3 CH3 146.8°C 10 4-1 CH3 CH3 156.7°C 11 4-Br CH3 CH3 146.5°C 12 H C2H5 H 146.4°C 13 3,4-Cl2 C2H5 H 138.7°C 14 4-Br CH3 H 162.7°C 15 H CH3 H 141.3°C Interm. R Rl R2 Physical data no. 48(*) H C13H27 H - 49 2-CH3 C6Hl3 H 155.1°C /HBr (*) ethanol was used as solvent instead of methanol Table 2 Example 4 a) A mixture of 51 parts of 2-bromo-l-(2-thienyl)ethanone, 28.5 parts of 5-methyl-2-thiazolamine and 240 parts of acetonitrile was stirred for 1 hour while heating on a water-bath. After cooling, the precipitate was filtered off, washed with ethanol and dried in vacuo , yielding 54 parts of 2-(2,3-dihydro-2-imino-5-methyl-3-thiazolyl)-l-(2-thienyl)ethanone hydrobromide; mp. 207.5-208°C (interm. 56). b) A mixture of 38 parts of intermediate 56, 19 parts of acetic anhydride, 19 parts of pyridine and 300 parts of trichloromethane was heated for 6 hours in a steam-bath. After cooling, the reaction mixture was washed with ammonium hydroxide. The organic layer was separated, dried, filtered and evaporated. The residue was recrystallized from methylbenzene, yielding 20 parts of £i-[2,3-dihydro-3-[2-oxo-2-(2-thienyl)ethyl]-5-methyl-2-thiazolylidene]acetarnide; mp. 187-188.5°C (interm. 57). c) To a stirred suspension of 7 parts of intermediate 57 in 100 parts of methanol there were added dropwise 0.95 parts of sodium tetrahydroborate. After stirring for 1 hour at room temperature, the solvent was evaporated. The residue was taken up in water and extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was recrystallized from hot methylbenzene, yielding 6 parts of M-[2,3-dihydro-3-[2-hydroxy-2-(2-thienyl)ethyl]-5-methyl-2-thiazolyUdene]acetamide; mp. 114-115°C (interm. 58).

In a similar manner there was also prepared H-[2,3-dihydro-3-[2-hydroxy-2-(2-thienyl)ethyl]-4-methyl-2-thiazolylidene]acetamide; mp. 105.5-107°C (interm. 59).

B. Preparation of the final compounds Example 5 A mixture of 4 parts of intermediate 4 and 36 parts of sulfuric acid was stirred for 1/2 hour at 0°C and for 1 1 2 hour at room temperature. The reaction mixture was poured into crushed ice and the whole was basified with NH4OH (aq.). The product was extracted with dichloromethane and the extract was dried, filtered and evaporated. The residue was converted into the ethanedioate salt in 2-propanol. The product was filtered off and dried, yielding 3 parts of 2-heptyl-5,6-dihydro-6-phenylimidazo[2,l-b]thiazole ethanedioate; mp. 108.7°C (comp. 34).

Example 6 To a stirred solution of 9.8 pans of intermediate 6 in 75 parts of trichloromethane there were added dropwise 5 parts of thionyl chloride. After stirring for 1 hour at 50°C, the reaction mixture was evaporated and the residue was taken up in 100 parts of Na2C03 (aq.) 2N. This solution was stirred for 1 hour at 90° C, cooled and extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was crystallized from a mixture of methylbenzene and petroleumether, yielding 3.5 parts of 6-(4-bromophenyl)-2-ethyl-5,c^hydroimidazo[2,l-b]thiazole; mp. 74.8°C (comp. 2).

Example 7 To a stirred and cooled (0°C) amount of 16 parts of thionyl chloride there were added portionwise 5.5 parts of intermediate 58 while keeping the temperature below 10°C. After stirring for 2 hours at room temperature, there were added 50 parts of acetic anhydride at a temperature below 20°C. The formed acetylchloride was distilled off (136°C) and the residue was evaporated. The residual oil was dissolved in a mixture of water and hydrochloric acid. After filtration, this solution was basified with NH4OH and extracted with methylbenzene. The extract was dried, filtered and evaporated. The residue was converted into the ethanedioate salt in 2-propanol. The salt was filtered off, washed with 2-propanone and dried, yielding 1.5 parts of (±)-5,6-dihydro-2-methyl-6- (2-thienyl)irnidazo[2,l-b]thiazole ethanedioate; mp. 170-171.5°C (comp. 56).

Example 8 To a solution of 5.3 parts of (S)-(+)-2-mercapto-4-phenyl-2-imidazoline (U.S.-3,274,209) in 63 parts of acetic acid there were added 6.2 parts of 2-bromo-octaldehyde. After stirring for 1 1/2 hour at reflux temperature, the solvent was evaporated. The residue was taken up in water and the whole was basified with ΝΉ4ΟΗ. The free base was extracted with methylbenzene and the extract was dried, filtered and evaporated. The residue was converted into the ethanedioate salt in 2-propanol. The salt was filtered off and dried, yielding 3.1 parts (27.4%) of product; mp. 132.7°C. The mother liquor was evaporated and the residue was treated with NH4OH. The product was extracted with dichloromethane and the extract was dried, filtered and evaporated. The residue was purified by column chromatography (silica gel ; CH2CI2 / CH3OH (NH3) 97.5:2.5). The eluent of the desired fraction was evaporated and the residue was converted into the ethanedioate salt as before, yielding 1.6 parts (14.2%) of product; mp. 136.3°C Total yield : 4.7 pans (41.6%) of (S)-(-)-2-hexyl-5,6-dihydro-6-phenyl-imidazo[2,l-b]thiazole ethanedioate(l:l) (comp. 50). [a]Q° (fraction 2) = -32.40°(conc.= 1% in CH3OH).

Compound 51 was prepared in a similar manner, using methanol as solvent instead of acetic acid and refluxing for 15 -hours instead of 1 1/2 hour.

Compound 52 was prepared similarly by first refluxing for 17 hours in methanol, then replacing the solvent by acetic acid and continuing reflux for 15 hours.

Example 9 A mixture of 1.78 parts of 2-mercaptc- -phenyl-2-irmdazoline, 44.5 parts of tetra-hydrofuran and 0.92 parts of a dispersion of sodium hydride in mineral oil (50%) was stirred for 45 min. at room temperature. There were added 1.5 parts of 2-chlorocyclo-hexanone and stirring was continued for 2 hours. The reaction mixture was diluted with water and then evaporated. The residue was stirred in HC1 2N for 15 min and then the whole was basified with NH4OH. The product was extracted with dichloromethane and the extract was dried, filtered and evaporated. The residue was purified twice by column chromatography (silica gel ; CH2C12 / CH3OH 95:5 ; CH2C12 / CH3OH / CH3OH(NH3) 97:2:1). The eluent of the desired fraction was evaporated and the residue was converted into the ethanedioate salt in tetrahydrofuran. The salt was filtered off and dried, yielding 1.6 parts (46.2%) of 2 .5,6,7,8-hexahydro-2-phenyl-imidazo[2,l-b]benzothiazole ethanedioate(l:l); mp. 146.2°C (comp. 53).

Example 10 3.8 parts of compound 33 were separated into the R and S isomers by preparative column chromatography (Chiracel OD®; hexanol / 2-C3H7OH 90: 10). The eluent of the (R)-(+) fraction was evaporated and the residue was converted into the ethanedioate salt in 2-propanol. The product was filtered off and dried, yielding 1.2 parts (24.0%) of (R)-(+)-2-hexyl-5,6-di ydrc^6-phenylimidazo-[2,l-b]thiazole ethanedioate(l:l); 20 mp. 135.1°C ; [o¾ = +32.23° (cone. = 1% in CH3OH) (comp. 54).

Evaporation of the eluent of the (S)-(-) fraction and similar treatment as for the (R)-(+) fraction yielded 1.1 parts (22.0%) of (S)-(-)-2-hexyl-5,6- iihydro-6-phenylimidazo- 20 [2,l-b]thiazole ethanedioate(l:l); mp. 142.2°C ; [a]D = -32.34° (cone. = 1% in CH3OH) (comp. 50).

All the other compounds listed in Table 3 and Table 4 were prepared following the procedure of the example referred to in the column Ex. No.

Table 3 Comp. Ex. R Rl R2 Physical data (mp.°Q no. no. 1 5 4-Cl CH3 CH3 154.4 / HNO3 2 6 4-Br C2H5 H 74.8 3 5 H CH3 CH3 157.3 / (COOH)2 4 5 4-Cl CH3 C2H5 136. /HCIO4 5 5 3-Br CH3 CH3 161.8 / (COOH)2 6 6 4-1 CH3 CH3 228.2 /HCIO4 7 5 4-Br CH3 CH3 154.5 / (COOH)2 8 5 H C2H5 H 164 (dec.) / (COOH)2 9 5 3,4-Cl2 C2H5 H 148.2 / (COOH)2 10 5 H CH3 H 82.8 11 5 4-Br CH3 H 178.5 / (COOH)2 12 5 3-Br CH3 H 142 / cyclohexanesulfamate Comp. Ex. R Rl R2 Physical data (mp.°C) no. no. 13 5 H C3H7 H 156.5 / cyclohexanesulfamate 14 5 3-Br C3H7 H 146-147 / cyclohexanesulfamate 15 6 4-1 CH3 H 190.9 /(COOH)2 16 5 4-Cl C3H7 H 138.6 /(COOH)2 17 5 3-NC-2 CH3 H 205.9 /HCl 18 5 3-NC-2 C3H7 H 204-205.3 /HC1 19 5 H C4H9 H 161.8 / cyclohexanesulfamate 20 5 H .-C3H7 H 174.2 /(COOH)2 21 5 3-Br C4H9 H 189 /HCl 22 5 4-Br C4H9 H 210.4 /HCl 23 5 3-NC-2 1-C3H7 H 205(dec.) / cyclohexanesulfamate 24 5 4-Br 1-C3H7 H 207.7 /HCl 25 5 4-Br C3H7 H 166.1 /(COOH)2 26 5 4-Br C6H13 H 132.3 /(COOH)2 27 5 4-Cl 1-C3H7 H 167.8 /(COOH)2 28 5 3-Br C6H13 H 188.3 /HCl 29 5 3-Br 1-C3H7 H 217 (dec.) /HCl 30 5 3-Br C5H11 H 189.5-192 /HCl 31 5 4-Br C5H11 H 210.6 /HCl 32 5 H C5H11 H 110.5/(COOH)2 33 5 H C6H13 H 110.1 /(COOH)2 34 5 H C7H15 H 108.7 /(COOH)2 35 5 H C8Hi7 H 149.2 (dec.) / HCl 36 5 H C10H21 H 152.4 /HCl 37 5 H C16H33 H 149.7 /HCl 38 5 H CllH23 H 143.8 /HCl 39 5 H C4H9 H 150.1 /HCl 40 5 H Cl2¾5 H 149.4 /HCl 41 5 H C18H37 H 149.1 /HCl 42 5 H C13H27 H 146.1 /HCl 43 5 4-Br H CH3 167.4 /(COOH)2 44 5 H H CH3 186.3 /(COOH)2 l 4 C. Pharmacological example The immunostimulating properties of the present compounds can be demonstrated in the following test procedures.

Example 11 Costimulating effect on ^H-thymidine incorporation in murine thymocytes stimulated by Concanavalin A. (described in Int. J. Immunopharm., 1, 233-237 (1979).

The culture medium consisted of Earle's minimal essential medium (MEM) supplemented with 100 U/ml penicillin, 100 ^πτΐ streptomycin and 2 mM L-glutamine (GD3CO, Grand Island, New York), together with 5% fetal calf serum (FCS).

Culture procedure Mouse thymuses were aseptically removed, teased with forceps in cold culture medium and filtered through a nylon gauze. The cells were then washed twice with medium. Cell counts and viability testing were carried out in a Neubauer hemocytometer.

Cultures were done in triplicate in 16x25 mm loosely capped plastic tubes (Falcon no. 3033). Cultures contained 10^ viable thymocytes, Con A (2 g) and test compound in a total volume of 1.0 ml. The tubes were incubated at 37°C in a 5% CO2 atmosphere.

After incubation for 64 h, the cells were pulsed for 4 h by adding 1 μθ of ¾-thymidine. After this time cultures were processed by washing once with 2 ml 0.9% NaCl and twice with 1 ml 5% trichloroacetic acid. The resulting precipitate was dissolved in 0.3 ml 0.5N sodium hydroxide, transferred to counting vials and 10 ml Instagel was added. Incorporation was measured using a Packard Tri-Carb liquid scintillation spectrometer.

The costimulation effect of the tested compounds was determined as follows.

For different concentrations of the test compound of formula (I), there was calculated the ratio between the number of cpm culture in the presence of Concanavalin A ^g/ml) and test compound, and the number of cpm/culture in the presence of Concanavalin A (2ug/ml) alone. Table 5 shows the concentration (uM) of test compound at which maximal costimulation effects (i.e. maximum calculated ratio) on 3H-thymidine incorporation were observed.

Table S Reference compound : levamisole : 100 uM D. Composition Examples.

The following formulations exemplify typical pharmaceutical compositions in dosage unit form suitable for systemic administration to warm-blooded animals in accordance with the present invention.

"Active ingredient" (A.I.) as used throughout these examples relates to a compound of formula (I), a pharmaceutically acceptable acid addition salt or a stereochemically isomeric form thereof.

Example 12 : Oral drops 500 g of the A.I. was dissolved in 0.5 1 of 2-hydroxypropanoic acid and 1.5 1 of the polyethylene glycol at 60~80°C. After cooling to 30~40°C there were added 35 1 of polyethylene glycol and the mixture was stirred well. Then there was added a solution of 1750 g of sodium saccharin in 2.5 1 of purified water and while stirring there were added 2.5 1 of cocoa flavor and polyethylene glycol q.s. to a volume of 50 1, providing an oral drop solution comprising 10 mg/ml of the A.I. The resulting solution was filled into suitable containers.

Example 13 : Oral solutions 9 g of methyl 4-hydroxybenzoate and 1 g of propyl 4-hydroxybenzoate were dissolved in 41 of boiling purified water. In 3 1 of this solution were dissolved first 10 g of 2,3-dihydroxybutanedioic a. idL and thereafter 20 g of the A.I. The latter solution was combined with the remaining part of the former solution and 12 1 1,2,3-propanetriol and 3 1 of sorbitol 70% solution were added thereto. 40 g of sodium saccharin were dissolved in 0.5 1 of water and 2 ml of raspberry and 2 ml of gooseberry essence were added. The latter solution was combined with the former, water was added q.s. to a volume of 20 1 providing an oral solution comprising 5 mg of the A.I. per teaspoonful (5 ml). The resulting solution was filled in suitable containers.

Example 14 : Capsules 20 g of the A.I., 6 g sodium lauryl sulfate, 56 g starch, 56 g lactose, 0.8 g colloidal silicon dioxide, and 1.2 g magnesium stearate were vigorously stirred together. The resulting mixture was subsequently filled into 1000 suitable hardened gelatin capsules, each comprising 20 mg of the A.I..

Example 15 : Film-coated tablets Preparation of tablet core A mixture of 100 g of the A.I., 570 g lactose and 200 g starch was mixed well and thereafter humidified with a solution of 5 g sodium dodecyl sulfate and 10 g polyvinylpyrrolidone (Kollidon-K 90®) in about 200 ml of water. The wet powder mixture was sieved, dried and sieved again. Then there was added 100 g microcrystalline cellulose (Avicel®) and 15 g hydrogenated vegetable oil (Sterotex ®). The whole was mixed well and compressed into tablets, giving 10.000 tablets, each comprising 10 mg of the active ingredient.

Coating To a solution of 10 g methyl cellulose (Methocel 60 HG®) in 75 ml of denaturated ethanol there was added a solution of 5 g of ethyl cellulose (Ethocel 22 cps ®) in 150 ml of dichloromethane. Then there were added 75 ml of dichloromethane and 2.5 ml 1,2,3-propanetriol. 10 g of polyethylene glycol was molten and dissolved in 75 ml of dichloromethane. The latter solution was added to the former and then there were added 2.5 g of magnesium octadecanoate, 5 g of polyvinylpyrrolidone and 30 ml of concentrated colour suspension (Opaspray K-l-2109®) and the whole was homogenated. The tablet cores were coated with the thus obtained mixture in a coating apparatus.

Example 16 : Injectable solutions 1.8 g methyl 4-hydroxybenzoate and 0.2 g propyl 4-hydroxybenzoate were dissolved in about 0.5 1 of boiling water for injection. After cooling to about 50°C there were added while stirring 4 g lactic acid, 0.05 g propylene glycol and 4 g of the A.L.The solution was cooled to room temperature and supplemented with water for injection q.s. ad 1 1 volume, giving a solution of 4 mg A.I. per ml. The solution was sterilized by filtration (U.S.P. XVII p. 811) and filled in sterile containers.

Exam le U ; Suppositories 3 g A.I. was dissolved in a solution of 3 g 2,3-dihydroxybutanedioic acid in 25 ml polyethylene glycol 400. 12 g surfactant (SPAN®) and triglycerides (Witepsol 555®) q.s. ad 300 g were molten together. The latter mixture was mixed well with the former solution. The thus obtained mixture was poured into moulds at a temperature of 37-38°C to form 100 suppositories each containing 30 mg of the A.I.

Claims (1)

Claims

1. ) A compound having the general formula a pharmaceutically acceptable acid addition salt thereof or a stereochemically isomeric form thereof, wherein X may be CHOH or C = O; Ar is phenyl optionally substituted with from 1 to 3 substituents each independently selected from halo, hydroxy, C1-6alkyloxy, mercapto, C1-6alkylthio, C1-6alkyl, nitro, amino, mono- and di(C1-6alkyl)amino, C1.6alkylcarbonylamino, arylcarbonylamino, trifluoromethyl, cyano, aminocarbonyl, mono- and • diiC^alky^aminocarbonyl, hydroxycarbonyl, C1.6alkyloxycarbonyl, formyl and hydroxymethyl; pyridinyl; thienyl; furanyl or furanyl substituted with either .galkyl or halo; R1 and R2 each independently are C1.20alkyl, ^^cycloalky Q^alkyl, C3-7cycloalkyl, aryl or (ary^Q.ealkyl; and one of R1 and R2 may also be hydrogen; or R1 and R2 taken together may also form a C3.6alkanediyl radical; each aryl independently is phenyl optionally substituted with from 1 to 3 substituents each independently selected from halo, hydroxy, C1-6alkyloxy, Q^alkyl, nitro, amino, trifluoromethyl or cyano; provided that when X is C = O, R2 is other than hydrogen when Ar is phenyl, methoxyphenyl, 4-fluorophenyl or 2-thienyl, and R1 is methyl, ethyl or phenylmethyl; and R2 is other than phenyl, methyl and phenylmethyl when Ar is phenyl, 4-halophenyl, 4-nitrophenyl or methoxyphenyl, and R1 is hydrogen or phenyl. A compound according to Claim 1 having the formula a pharmaceutically acceptable acid addition salt thereof or a stereochemically isomeric form thereof, wherein Ar, R1 and R2 are as defined in Claim 1. A compound according to Claim 1 having the formula a pharmaceutically acceptable acid addition salt thereof or a stereochemically isomeric form thereof, wherein Ar, R1 and R2 are as defined in Claim 1, provided that R2 is. other than hydrogen when Ar is phenyl, methoxyphenyl, • 4-fluorophenyl or 2-thienyl, and R1 is methyl, ethyl or phenylmethyl; and R2 is other than phenyl, methyl and phenylmethyl when Ar is phenyl, 4-halophenyl, 4-nitrophenyl or methoxyphenyl, and R1 is hydrogen or phenyl. For the Applicants, NB/prg