JPH048429B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a novel 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative, and more particularly, to a method for producing a novel 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative, and more particularly, to The following general formula with () (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 of the X's being the same or different and representing a hydrogen atom, a halogen atom, a trifluoromethyl group, a lower alkyl group, a lower alkoxy group, a cyano group, or a nitro group; n is 0 to 5; The present invention relates to a method for producing a 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative or a salt thereof, represented by the following integer: [Prior Art] Conventionally, many compounds having an imidathiazole 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 such circumstances, the present inventors synthesized various imidazo[2,1-b]thiazole derivatives and investigated 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 expressed by the formula ()
-Methyl-5,6-dihydroimidazo[2,1-
b] A method for producing a thiazole-2-carboxamide derivative or a salt thereof is provided. 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 () 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 () of the present invention is 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
has the above meaning) This reaction is preferably carried out in a suitable inert solvent, examples of which include benzene, toluene,
xylene, acetone, methyl ethyl ketone, dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, 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 the general formula () from the hydrochloride thus obtained, a base, for example an inorganic base such as sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, ammonia, etc. It may be treated with an organic base such as pyridine or triethylamine. In order to lead to other salts, 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,
The above hydrochloride or free compound may be treated with glutamic acid, aspartic acid, etc. The compound of formula () used as a raw material in this method is, for example, Pharmaceutical Journal, 89 (11), 1477-1481.
(1969) etc., diketene () is reacted with amines () to form a compound of formula () according to the following reaction formula, which is then converted to sulfuryl chloride [Chemical Abstracts ( Chemical Abstracts) 19 , 43 (1925), 74 ,
42102t (1971)] or 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.),
Coll.3, p.394 or J.Med.Chem.18(5), 447-453
(1975), as follows. [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)
The cells were cultured in a CO ₂ incubator (37°C) for 5 days in a medium [Michelle, Earl. Eye (Mischell,
(J.Exp.Med.) 126:423 (1967)], the number of plaque-forming cells that appear is calculated by Jerne and Nordin.
method [Science 140:405 (1963)]
It was measured with The results are shown in Table 1-1. 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) were similarly tested. The effects on in vitro plaque-forming cell 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 rejuvenation reaction using mouse splenocytes: BALB/c mouse splenocytes (1 x 10 ³ cells) or thymocytes (2 x 10 ^-5 cells) were treated with T cell mitogen. ConA (2.5μg/ml) and test compound (1μg/ml)
ml) in RPMI-1640 medium (0.2 ml) containing 5% fetal bovine serum in a CO ₂ incubator (37 °C).
The cells were cultured for 48 hours. Next, 0.5 μCi of ³ H-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. Obvious due to the addition of the compound of the present invention
Increased uptake of ^3H -thymidine was observed.

[Table] Test Example 3 Effect on lymphocyte blastogenesis upon oral administration of test compound: Six BALB/c female mice were used per group.
0.25 mg/Kg of the test compound was orally administered once a day for 5 days, and on the 6th day, the spleen was removed and splenocytes (2 × 10 ⁵
mitogenes (LPS: 10μg/ml or Con
A: 2.5 μg/ml), and the method of Test Example 2 was followed to measure the lymphocyte blastogenesis. The results are shown in Table 3.

[Table] In this test, levamisole required administration of 2.5 mg/Kg/day to show its effect, but the compound of the present invention was administered at 1/10th the dose of 0.25 mg/Kg/day, which was equivalent to or better than levamisole. It showed the above promoting activity. 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 hind leg, and physiological saline was injected into the footpad of the other 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. Adjuvant arthritis was induced by injecting 0.6 mg/0.1 ml of killed Mycobacterium tuberculosis suspended in liquid paraffin as an adjuvant into the pad of one hind leg, and the test compound was orally administered once a day for 20 days. After 21 days, the volume of the pads of both hind legs 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
Administration of mg/Kg/day significantly suppressed edema in non-adjuvant-injected feet and in adjuvant-injected feet.

[Table] Test Example 6 Side effects and blood concentration: 300 mg/Kg of the test compound was orally administered to 4 male Wistar rats once a day for 4 days, and changes in general symptoms were observed. body weight,
The effects on liver weight and serum cholesterol levels were investigated. Serum cholesterol was measured using a Baker cholesterol measuring kit with a Centrifikem autoanalyzer. The compound of the present invention is Compound 1, and the comparative compound is (), where:
R ₁ = R ₃ = R ₄ = H, () _o = 3, 4-Cl ₂ compound (comparative compound 6) and R ₁ = R ₃ = R ₄ = H, () _o =
A compound of ₃ -CF3 (comparative compound 7) was used, and levamisole was used in some tests. In addition, blood concentrations of the test compounds were compared after one administration and after administration for 4 days. High performance liquid chromatography was used to measure blood concentration. (1) Effects on general symptoms No changes were observed in general symptoms in the Compound 1 and Comparative Compound 6 administration groups, but in the Comparative Compound 7 administration group, lacrimation, bleeding from the eyes, sedation, imbalance, and tremors occurred. A battle was seen. Half of the patients in the levamisole group died. (2) Effect on body weight The body weight before and after continuous administration of the test compound is shown in Table 6.
Shown below.

[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; however,
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 of the present invention () has an excellent immunomodulatory effect, so it can be used as a prophylactic and therapeutic drug for immune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, collagen disease, chronic nephritis, autoimmune disease, etc. It can be used for the treatment and prevention of autoimmune diseases such as immune-mediated 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; and injections. , syrups, inhalants, emulsions, suspensions, and other liquid preparations. 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 catalytic 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 (i) 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 product. 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 by filtration, washed with acetone, and recrystallized from isopropanol/isopropyl ether to yield 4.8 g of N-(4-chlorobenzyl)-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. (ii) 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 by filtration and purified by washing with a large amount of water. This material was dried under reduced pressure, and 3.3 g of N-(4-chlorobenzyl)-N,
3,6,6-tetramethyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide [melting point 139°C, pale yellow powder crystals] 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. This was poured into water, extracted with carbon tetrachloride, washed with water, dried, and concentrated. The resulting oily substance was subjected to 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 3 hours. After cooling, the precipitate was collected by filtration, 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.
White crystals, melting point 241-242℃. Example 3 N-(3-trifluoromethylbenzyl)acetoacetamide (2.6 g, 0.01 M) obtained in the same manner as Reference Example 1, N-chlorosuccinimide (1.3 g, 0.01 M), and a small amount of benzoyl peroxide were mixed together. The mixture was suspended in carbon chloride 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, 0.01M) was suspended in methyl ethyl ketone and heated under reflux for 3 hours. After cooling, the precipitate formed was collected by filtration, washed with acetone,
Recrystallize with ethanol and 3-methyl-N-
(3-trifluoromethylbenzyl)-5,6-dihydroimidazo[2,1-b]thiazole-2-
Carboxamide 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 (1.3 g, 0.01M) were dissolved in methyl ethyl ketone and heated under reflux for 3 hours. After cooling, the resulting precipitate was collected by filtration, washed with acetone, and recrystallized with isopropanol/isopropyl ether to give N-(4-chlorobenzyl).
-N-ethyl-3,6,6-trimethyl-5,6
-dihydroimidazo[2,1-b]thiazole-
2-carboxamide hydrochloride (compound 4) (melting point 178
-181°C, white crystals) 2.7g was 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, 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 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 by filtration, 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, dried 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 by filtration, washed and purified with a large amount of acetone, and N-(3,4-dichlorobenzyl)-3,5,6-trimethyl-5,6-dihydroimidazo[2,1-b ] Thiazole-2-carboxamide hydrochloride (compound 6) (melting point 148-152℃,
A 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 purification. 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 by filtration, washed and purified with acetone and isopyl ether to give N-(3-chlorobenzyl)-N,3,6-trimethyl-5,6-dihydroimidazo[2,1-b ] Thiazole-2-carboxamide hydrochloride (compound 7) (melting point 41-47℃,
A brown glassy substance) was obtained. Example 8 (i) 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 by filtration, 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. (ii) Obtained N-(2,4-dichlorobenzyl)-
3.6 g (0.01 M) of N,3-dimethyl-5,6-dihydroimidazo[2,1-b]thiazole carboxamide hydrochloride was dissolved in water, and aqueous ammonia was added dropwise to the solution while stirring at room temperature. The resulting precipitate was collected by filtration, washed with a large amount of water, and purified with 3.0 g of N.
-(2,4-dichlorobenzyl)-N,3-dimethyl-5,6-dihydroimidazo[2,1-
b] Thiazole-2-carboxamide (melting point 55
−60°C, pale yellow powder) was obtained. Examples 9 to 94 The compounds shown in Table 10 below were produced in the same manner as in Reference Example 1 and Examples 1 to 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 In 10 ml of methyl ethyl ketone, 2.5 g of 2-chloro-N-(2-phenylethyl)acetoacetamide (unpurified) obtained in the same manner as in Reference Example 1 and the first part of Example 1 (i) using β-phenethylamine and 4, 4-dimethylimidazolidine-2-thione
1.3g was dissolved and heated under reflux for 3 hours. cool,
After 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. Furthermore, 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 the compound as white needle-like crystals (melting point 120-121℃).
1.1g of 98 was obtained.

Claims (1)

[Claims] First-order general formula () (In the formula, A is a lower alkylene group that may be branched, R ₅ is a hydrogen atom, a lower alkyl group, or a cycloalkyl group, and n X's are the same or different and are a hydrogen atom, a halogen atom, a trifluoro A methyl group, a lower alkyl group, a lower alkoxy group, a cyano group, or a nitro group, n is an integer of 0 to 5. (wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different and represent a hydrogen atom or a lower alkyl group) (In the formula, A, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , X and n
has the above-mentioned meaning) A method for producing a 3-methyl-5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivative or a salt thereof.