JPH0353316B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to novel 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivatives, more particularly to the following compounds which have excellent immunomodulatory uses: General formula (I) (In the formula, A is a lower alkylene group which may be branched, R ₁ , R ₂ , R ₃ and R ₄ are the same or different and represent a hydrogen atom or a lower alkyl group, R ₅ is a hydrogen atom,
a lower alkyl group or a cycloalkyl group, n X's are the same or different, a hydrogen atom, a halogen atom,
trifluoromethyl group, lower alkyl group, lower alkoxy group, cyano group or nitro group, n is 0 to
The present invention relates to a 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative or a salt thereof represented by the formula (indicating an integer of 5). [Prior Art] Conventionally, many compounds having an imidazothiazole skeleton have been synthesized, for example, the following formula: It has been reported that the imidazo[2,1-b]thiazole derivative (levamisole) represented by
issue). Also, the expression (In the formula, R ₉ is C ₁ to C ₃ alkylsulfonyl or

[Means for solving problems]

Under these circumstances, the present inventors synthesized various imidazo[2,1-b]thiazole derivatives and examined their physiological activities. 3-methyl-5,6-dihydroimidazo[2,1-b]
The present invention was completed based on the discovery that thiazole-2-carboxamide derivatives have excellent immunomodulatory effects. That is, the present invention provides 3 represented by the formula (I)
-Methyl-5,6-dihydroimidazo[2,1-
b] Thiazole-2-carboxamide derivatives and salts thereof. In the present invention, the salts of the 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative include pharmaceutically acceptable salts such as hydrochloride, sulfate, carbonate, Inorganic or organic acid salts such as nitrates, hydrobromides, phosphates, sulfonates, acetates, oxalates, tartrates, citrates, malates, glutamates, aspartates, etc. can be mentioned. Further, the compound of formula (I) and its salt of the present invention may have water of crystallization, and any of these hydrates are included within the scope of the present invention. The compound (I) of the present invention can be produced, for example, by reacting an amide represented by the formula () with an imidazolidine-2-thione represented by the formula (), according to the following reaction formula. (In the formula, A, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , X and n have the above-mentioned meanings) This reaction is preferably carried out in a suitable inert solvent, such as benzene, toluene,
xylene, acetone, methyl ethyl ketone, dimethyl formamide, dimethyl acetamide, dimethyl forskide, acetonitrile, ether,
Tetrahydrofuran, dioxane, chloroform, water, etc. are used. The reaction temperature is -5°C to 100°C, preferably 20°C to
The temperature is 80°C, and the compound of the present invention can be obtained in high yield and purity by reaction for 1 to 6 hours. In order to obtain the free compound of general formula (I) from the hydrochloride thus obtained, bases such as sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, ammonia and other inorganic It may be treated with a base, an organic base such as pyridine, or triethylamine. In order to lead to other salts, the corresponding acids such as sulfuric acid, carbonic acid, nitric acid, hydrobromic acid, phosphoric acid, sulfonic acid, acetic acid, oxalic acid, tartaric acid, citric acid, malic acid, glutamic acid, aspartic acid, etc. The above hydrochloride or free compound may be treated with. The compound of the formula () used as a raw material in this method is, for example, prepared by converting diketene () into a compound of the formula () of amines () according to the following reaction formula, and then converting this into sulfuryl chloride [Chemical Abstracts) 19 , 43 (1925)]
Alternatively, it is produced by chlorination with N-chlorosuccinimide or the like. (In the formula, A, R ₅ , X and n have the above-mentioned meanings.) In addition, another raw material compound () is, for example, Organic Synthesis (Org.Synth.),
It is produced by the following method according to the method described in Coll. 3, page 394. [Effect] Next, the pharmacological effects of the compound of the present invention () and its salt will be explained. Test Example 1 Effect on in vitro plaque-forming cell response using mouse splenocytes: 1 x 10 ⁷ BALB/c mouse splenocytes were injected with sheep red blood cells (1 x 10 ⁶ ) and test compound (0.2 or 1 μg/
RPMI−1640 containing 10% fetal bovine serum (ml)
Cultured in a CO ₂ incubator (37°C) for 5 days in a medium [Michelle, Earl. Eye (Mischell, R.
(J.Evp.Med.) 126:423 (1967)], the number of appearing plaque-forming cells was determined by the method of Jerne and Nordin [Science 140:405]. (1963). The results are shown in Table 1-1.

【table】

[Table] Also, for comparison, the following compounds described in JP-A-52-106893 and Journal of Medicinal Chemistry (J.Med.Chem.), 24 , 604-609 (1981) The effects on in vitro plaque-forming cellular responses were determined.
The results are shown in Table 1-2.

[Table] As is clear from Tables 1-1 and 1-2, the compounds of the present invention exhibit immune response activity at low concentrations of 0.2 to 1 μg/ml, whereas the comparative compounds exhibit almost no activity. Test Example 2 Effect on in vitro lymphocyte blastogenesis using mouse splenocytes: BALB/c mouse splenocytes (1×10 ⁵ cells) or thymocytes (2×10 ⁻⁵ cells) were treated with T cell mitogen. ConA (2.5μg/ml) and test compound (1μg/ml)
RPMI containing 5% fetal bovine serum (g/ml)
The cells were cultured in 1640 medium (0.2 ml) in a CO ₂ incubator (37°C) for 48 hours. Then 0.5 μCi of ^3H−
Thymidine was added and cultured for an additional 18 hours, and the radioactivity of ³ H-thymidine incorporated into the cells was measured.
The results are shown in Table 2. A clear increase in the uptake of ³ H-thymidine was observed with the addition of the compound of the present invention.

[Table] Test Example 3: Effect on lymphocyte rejuvenation response when test compound was administered selectively: Six BALB/c female mice were used in each group.
The test compound was orally administered at 0.25 mg/Kg per day for 5 days.
On the 6th day, the spleen was removed and splenocytes (2 x ¹⁰ cells) were treated with mitogen (LPS: 10 μg/ml or ConA: 2.5 μg/ml).
g/ml), and the lymphocyte maturation reaction was examined. The culture conditions and the measurement of lymphocyte blastogenesis were conducted according to the method of Test Example 2. The results are shown in Table 3.

[Table] For levamisole to show effect in this study
Although it required administration of 2.5 mg/Kg/day, the compound of the present invention showed a promoting activity equal to or greater than that of levamisole when administered at 1/10 the dose of 0.25 mg/Kg/day. Test Example 4 Effect on delayed allergic reaction: One group of 8 male ddY mice were sensitized by subcutaneously injecting 2 x 10 ⁸ sheep red blood cells into the back. 4 days after sensitization,
5 x 10 ⁷ sheep red blood cells were subcutaneously injected into the footpad of one side of the hind leg, and physiological saline was injected into the footpad of the opposite side. After 24 hours, the thickness of both footpads was measured with a micrometer to determine the edema rate. Ta. The test compound was orally administered once a day for 5 days from the day of sensitization (2 hours after sensitization). The results are shown in Table 4.

[Table] The compound of the present invention significantly inhibited delayed allergic reactions when administered at 0.1 mg/Kg/day. Test Example 5 Effect on adjuvant arthritis: One group of 8 female Lewis rats were used. Abajuvant arthritis was induced by injecting 0.6 mg/0.1 ml of killed Mycobacterium tuberculosis suspended in liquid paraffin as an adjuvant into the footpad of one hind leg, and the test compound was orally administered once a day for 20 days. After 21 days, the volume of both limbs and footpads was measured, and the edema rate of each was determined. The results are shown in Table 5. The compound of the present invention is 1 to 5 mg/
Kg/day administration significantly suppressed edema in the non-adjuvant-injected feet and in the adjuvant-injected feet.

[Table] Test Example 6 Side effects and blood concentration: Wistar
The test compound was orally administered at 300 mg/kg once a day for 4 days to 4 male rats per group, and changes in general symptoms were observed, and the effects on body weight, liver weight, and serum cholesterol level were examined. Serum cholesterol was measured using a Beca cholesterol measurement kit and a Centrifikem autoanalyzer. Compound 1 _is used as the compound of the present invention, and compound _{1 is} used as the comparative compound.
3,4-Cl ₂ compound (relatively soft compound) and R ₁ = R ₃
= _R4 =H, (X)n3= _-CF3 compound (comparative compound 7 was used, and levamisole was used in some tests. Blood concentrations of the compounds were also compared. High performance liquid chromatography was used to measure blood concentrations. (1) Effects on general symptoms There were no changes in general symptoms in the Compound 1 and Comparative Compound 6 administration groups. However, with Comparative Compound 7, lacrimation, bleeding from the eyes, sedation, imbalance, and tremor were observed in the treated group. Half of the patients in the reversisol-treated group died. (2) Effect on body weight Table 6 shows the body weights before and after continuous administration of the test compound.

[Table] Compound 1 had no effect on body weight, but comparative compound 6 significantly reduced body weight. Levamisole significantly reduced body weight even when administered at 100 mg/Kg/day. (3) Effect on liver weight The results obtained are shown in Table 7. Compound 1 had no significant effect on liver weight, whereas comparative compound 6 significantly increased liver weight.

[Table] (4) Effect on serum cholesterol level The test results are shown in Table 8. Compound 1 had no significant effect on serum cholesterol levels, whereas comparative compounds 6 and 7 and levamisole significantly increased cholesterol levels.

【table】

[Table] (5) Changes in blood concentration due to continuous administration Table 9 shows the blood concentrations at the 1st hour and 2nd hour after one administration and once a day for 4 days, respectively. The blood concentration of Compound 1 was close to the blood concentration after a single administration even after 4 days of administration, but the blood concentrations of Comparative Compounds 6 and 7 were significantly reduced by continuous administration. .

〔effect〕

As is clear from the above test results, the compound (I) of the present invention has an excellent immunomodulatory effect, and therefore can be used as a prophylactic and therapeutic agent for immune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, collagen disease, chronic nephritis, etc. It can be used for the treatment and prevention of autoimmune diseases such as autoimmune hemolytic anemia, immediate and delayed allergic diseases, malignant tumors, severe infections, and the like. The compounds of the present invention can be administered orally or parenterally (eg, intramuscularly, subcutaneously, intravenously, anally, or cutaneously) as such or in various dosage unit forms. The dosage forms include solid preparations such as tablets, sugar-coated tablets, film tablets, hard or soft capsules, troches, pills, granules, and powders; semi-solid preparations such as suppositories, patches, and ointments; injections, It can be made into liquid preparations such as syrups, inhalants, emulsions, and suspensions. Although the compound of the present invention can be used alone as the above-mentioned preparation, it may also be combined with other medicinal ingredients such as non-steroidal analgesics, anti-inflammatory agents, etc. [Example] Next, reference examples and examples will be given and explained. Reference Example 1 4-Chloro-N-methyl-benzylamine (3.1 g, 0.02M) was dissolved in toluene, a contact amount of pyridine was added, and diketene (1.8 g,
0.022M) was added dropwise. The reaction solution was stirred at room temperature for 3 hours, poured into water, extracted with toluene, and purified to obtain oily N-methyl-N-(4-chlorobenzyl)-acetoacetamide. Example 1 () N-methyl-N-(4
-chlorobenzyl)acetoacetamide (4.0g,
0.017M), N-chlorosuccinimide (2,
3g, 0.017M) and a small amount of benzoyl peroxide were suspended in carbon tetrachloride and heated under reflux for 1 hour. After cooling, it was poured into water, extracted with carbon tetrachloride, purified, dried, and concentrated to obtain an oily crude composition. This material was added to a silica gel column (c-300,
Purification was performed using n-hexane-ethyl acetate) to obtain 3.5 g of oily N-methyl-N-(4-chlorobenzyl)-2-chloro-acetoacetamide ( ^n20D : _1.5336 ). This substance and 4,4-dimethylimidazolidine-2-thione (1.7 g,
0.013M) in methyl ethyl ketone,
After heating under reflux for an hour and cooling, the resulting precipitate was collected, washed with ascent, and recrystallized from isopropanol/isopropyl ether to yield 4.8 g of N-(4-chloropenzyl)-N,3,6,6-
Tetramethyl-5,6-dihydroimidazo[2,1-b]thiazole, -2-carboxamide hydrochloride (Compound 1) (melting point 187-190°C, white crystals) was obtained. () 3.9 g (0.01 M) of the obtained hydrochloride was dissolved in water, and 10% caustic soda water was added dropwise to the solution while stirring at room temperature. The resulting crystals were collected and purified by washing with a large amount of water. This material was dried under reduced pressure.
3.3 N-(4-chloropenzyl)-N,3,6,
6-Tetramethyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide (melting point 139°C, pale yellow powder crystal) was obtained. Example 2 N-(4-chlorobenzyl)acetoacetamide (2.3 g, obtained in the same manner as Reference Example 1)
0.01M) and N-chlorosuccinimide (1.3g,
0.01M) and a small amount of benzoyl peroxide were suspended in carbon tetrachloride and heated under reflux for 1 hour. After pouring this into water and extracting with carbon tetrachloride,
After washing with water, drying, and concentrating, the obtained oily substance was subjected to the next reaction without being purified. The compound thus obtained and imidazolidine-2-thione (1.0 g, 0.01 M) were suspended in methyl ethyl ketone and heated under reflux for 3 hours. After cooling, the precipitate was collected, washed with acetone, and recrystallized with isopropyl alcohol/isopropyl ether.
-(4-chlorobenzyl)-3-methyl-5,6-
Dihydroimidazo[2,1-b]thiazole-2
-2.8 g of carboxamide hydrochloride (compound 2) was obtained. Melting point: 241-242℃, white crystals. Example 3 N-(3-trifluoromethylbenzyl)acetoacetamide (2.6 g, 0.01 M) obtained in the same manner as in Reference Example 1, N-chlorosuccinimide (1.3 g, 0.01 M) and a small amount of benzyl peroxide were added. The mixture was suspended in carbon tetrachloride and heated under reflux for 1 hour. After cooling, the reaction solution was poured into water, extracted with carbon tetrachloride, washed with water, dried and concentrated, and the obtained oily substance was used in the next reaction without purification. The compound thus obtained and imidazolidine-2-thione (1.0 g, 0.01 M) were suspended in methylethylcetone and heated under reflux for 3 hours.
After cooling, the resulting precipitate was collected, washed with acetone, and recrystallized with ethanol to obtain 3-methyl-N.
-(3-trifluoromethylbenzyl)-5,6-
Dihydroimidazo[2,1-b]thiazole-2
-Carbosisamide hydrochloride (compound 3) (melting point 210~
216°C, 2.5 g of colorless prismatic crystals were obtained. Example 4 N-ethyl- obtained in the same manner as Reference Example 1
N-(4-chlorobenzyl)acetoacetamide (2.5 g, 0.01 M), N-chlorosuccinimide (1.3 g, 0.01 M) and a small amount of benzoyl peroxide were suspended in carbon tetrachloride and heated under reflux for 1 hour. Ivy. After cooling, the reaction solution was poured into water, extracted with carbon tetrachloride, washed with water, dried, and concentrated. The resulting oily substance was used in the next reaction without purification.
The compound thus obtained and 4,4-dimethylimidazolidine-2-thione (1.3g, 0.01M)
was dissolved in methyl ethyl ketone and heated under reflux for 3 hours. After cooling, the resulting precipitate was collected, washed with acetone, and recrystallized from isopropanol/isopropyl ether to obtain N-(4-chlorobenzyl)-N-ethyl-3,6,6-trimethyl-5,
6-dihydroimidazo[2,1-b]thiazole-2-carboxamide hydrochloride (compound 4) (melting point
2.7 g of white crystals (178-181°C) were obtained. Example 5 N-methyl- obtained in the same manner as Reference Example 1
N-(3,4-dichlorobenzyl)acetoacetamide (2.6 g, 0.01 M), N-chlorosuccinimide (1.3 g, 0.01 M), and a small amount of benzoyl peroxide were suspended in carbon tetrachloride and heated under reflux for 1 hour. I went there. After cooling, the reaction solution was poured into water.
After extraction with carbon tetrachloride, the oily substance obtained by washing with water, drying, and concentrating was used for the next reaction without purification. The compound thus obtained and imidazolidine-2-thione (1.0 g, 0.01 M) were suspended in methyl ethyl ketone and heated under reflux for 3 hours. After cooling, the resulting precipitate was collected, washed with acetone, and recrystallized with ethanol to obtain N-(3,
4-dichlorobenzyl)-N,3-dimethyl-5,
6-dihydroimidazo[2,1-b]thiazole-2-carboxamide hydrochloride (compound 5) (melting point
3.1 g of pale yellow microacicular crystals (196-198°C) were obtained. Example 6 N-(3,4
-dichlorobenzyl)-acetoacetamide (5.2
g, 0.02M) and N-chlorosuccinimide (2.7
g, 0.02M) and a small amount of benzoyl peroxide were suspended in carbon tetrachloride and heated under reflux for 1 hour. After cooling, it was poured into water, extracted with carbon tetrachloride, washed with water, and concentrated, and the obtained oily substance was subjected to the next reaction without being purified. The compound thus obtained and 4,5-dimethylimidazolidine-2-thione (2.6 g, 0.02M) were dissolved in methyl ethyl ketone and heated under reflux for 3 hours.
After cooling, the precipitate was collected and purified by washing with a large amount of acetone to obtain N-(3,4-dichlorobenzyl)-
3,5,6-trimethyl-5,6-dihyloimidazo[2,1-b]thiazole-2-carboxamide hydrochloride (compound 6) (melting point 148-152°C, white powder) was obtained. Example 7 N-(3-chlorobenzyl)N-methylacetoacetamide (4.8g, 0.02M) obtained in the same manner as in Reference Example 1, N-chlorosuccinimide (2.7g, 0.02M) and a small amount of benzoyl. Peroxide was suspended in carbon tetrachloride and heated under reflux for 1 hour. This was poured into water, extracted with carbon tetrachloride, washed with water, dried and concentrated, and the obtained oily substance was subjected to the next reaction without being purified. The compound thus obtained and 4-methylimidazolidine-2-thione (2.4 g, 0.02M) were dissolved in methyl ethyl ketone and heated under reflux for 3 hours. After cooling, the precipitate was collected and purified by washing with acetone and isopropyl ether to obtain N-(3-chlorobenzyl)-N,3,6-trimethyl-5,6-dihydroimidazo[2,1-b]thiazole-2. - Carboxamide hydrochloride (compound 7) (melting point 41-47°C,
A brown glassy substance) was obtained. Example 8 () N-(2,
4-dichlorobenzyl)-N-methylacetoacetamide (5.2 g, 0.02 M), N-chlorosuccinimide (2.7 g, 0.02 M), and a small amount of benzoyl peroxide were suspended in carbon tetrachloride for 1 hour. The mixture was heated to reflux. After cooling, the reaction solution was poured into water, extracted with carbon tetrachloride, washed with water, dried,
It was concentrated, and the obtained oily substance was used in the next reaction without purification. The compound thus obtained and imidazolidine-2-thione (1.0 g,
0.01M) in methyl ethyl ketone,
The mixture was heated under reflux for an hour. After cooling, the resulting precipitate was collected, washed with acetone, and purified.
(2,4-dichlorobenzyl)-N,3-dimethyl-5,6-dihydroimidazo[2,1-b]
5.3 g of thiazole-2-carboxamide hydrochloride (compound 8) (melting point 251-254°C, colorless powder) was obtained. () Obtained N-(2,4-dichlorobenzyl)
3.6 g (0.01 M) of -N,3-dimethyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide hydrochloride was dissolved in water, and aqueous ammonia was added dropwise with stirring at room temperature. Collect the resulting precipitate and wash and purify it with a large amount of water.
3.0 g of N-(2,4-dichlorobenzyl)-N,
3-dimethyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide (melting point 55-56°C, pale yellow powder) was obtained. Examples 9-94 The compounds shown in Table 10 below were produced in the same manner as in Reference Example 1 and Examples 1-8 above.

【table】

【table】

【table】

[Table] Examples 95 to 99 The compounds shown in Table 11 below were produced in the same manner as in the above Reference Examples and Examples.

[Table] Example 100 2-chloro-N-(2-phenylethyl)acetoacetamide (unpurified) obtained in the same manner as in Reference Example 1 and Example 1 () using β-phenethylamine in 10 ml of methyl ethyl ketone (unpurified) 2.5
g and 1.3 g of 4,4-dimethylimidazolidine-2-thione were dissolved and heated under reflux for 3 hours. After cooling and concentrating to remove methyl ethyl ketone,
The residue was dissolved in 20 ml of water. Add this aqueous solution to 10% sodium hydroxide solution 20%
ml and toluene (20 ml) under stirring. The precipitated crystals were collected by filtration, washed with 20 ml of water, and dried to give N-(2-phenylethyl)-3,6,6
-trimethyl-5,6-dihydroimidazo[2,
1-b] 2.5 g of thiazole-2-carboxamide (compound 98, light brown powder, melting point 102-105°C) was obtained. Further, 2.5 g of this light brown powder was dissolved in 10 ml of isopropyl alcohol, and then 20 ml of isopropyl ether was gradually added. The precipitated crystals were collected by filtration, washed with 10 ml of isopropyl ether, and dried to give compound 98 as white needle-like crystals (120-121°C).
1.1g of was obtained.

Claims (1)

[Claims] First-order general formula (I) (In the formula, A is a lower alkylene group that may be branched, R ₁ , R ₂ , R ₃ and R ₄ are the same or different and represent a hydrogen atom or a lower alkyl group, R ₅ is a hydrogen atom,
a lower alkyl group or a cycloalkyl group, n X's are the same or different, a hydrogen atom, a halogen atom,
trifluoromethyl group, lower alkyl group, lower alkoxy group, cyano group or nitro group, n is 0 to
A 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative or a salt thereof represented by: