JPH0536434B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a novel pyrazine derivative and a pharmaceutical formulation containing the same. Since the pyrazine derivatives of the present invention have a strong platelet aggregation inhibiting effect, they are effective in preventing diseases caused by platelet aggregation, such as thrombosis. Furthermore, compounds having a cyclooxygenase inhibitory effect are generally known to have an anti-inflammatory effect, and since the pyrazine derivative of the present invention has the above-mentioned inhibitory effect, it can also be used as an anti-inflammatory agent. [Prior Art and Problems to be Solved by the Invention] Various substances having antiplatelet aggregation effects are known, but their effects are weak, and there is a desire for a more improved drug. In addition, thrombosis such as myocardial infarction and cerebral thrombosis has recently become a large proportion of adult diseases, and there is a strong desire for an antithrombotic agent to effectively prevent this. Various pyrazine derivatives have been known, for example, 2,3-
Diphenylpyrazine is mentioned. However, it has not been known so far that these pyrazine derivatives have an anti-platelet aggregation inhibitory effect. The present inventors synthesized many novel pyrazine derivatives and conducted intensive research on their pharmacological activities. As a result, they discovered that certain pyrazine derivatives have excellent platelet aggregation inhibiting and anti-inflammatory effects, and completed the present invention. I let it happen. Therefore, it is an object of the present invention to provide novel pyrazine derivatives. A further object of the present invention is to provide a platelet aggregation inhibitor and an anti-inflammatory agent containing a pyrazine derivative as an active ingredient. [Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration. 1 formula (In the formula, X represents a hydrogen atom, a cyano group or a lower alkoxy group, R ₁ represents a hydrogen atom or a halogen atom, R ₂ represents a hydrogen atom, a halogen atom,
It represents a lower alkyl group, a cyano group, a naphthylmethyl group, a substituted benzyl group having a halogen atom or a lower alkylamino group as a substituent, a carboxyl group, or a lower alkyloxycarbonyl group. ) pyrazine derivatives. 2. A platelet aggregation inhibitor and anti-inflammatory agent containing a pyrazine derivative having the above general formula (). According to the present invention, a novel pyrazine derivative having the above formula () is provided. In the above formula (), X is a hydrogen atom, a cyano group or a lower alkoxy group (e.g. methoxy, ethoxy, propoxy, isopropoxy, butoxy,
isobutoxy). R ₁ represents a hydrogen atom or a halogen atom (eg, chlorine, bromine, fluorine atom). R ₂ is a hydrogen atom, a halogen atom (e.g. chlorine,
bromine, fluorine atoms), lower alkyl groups (e.g. methyl, ethyl, propyl, isopropyl, butyl,
isobutyl), cyano group, naphthylmethyl group, carboxyl group, lower alkyloxycarbonyl group (e.g. methoxycarbonyl, ethoxycarbonyl, propioxycarbonyl, isopropiooxycarbonyl, butoxycarbonyl, isobutoxycarbonyl) or formula () (In the formula, R ₃ is a halogen atom (e.g. chlorine, bromine,
fluorine atom) or lower alkylamino groups (e.g. methylamino, ethylamino, propylamino,
isopropylamino, butylamino, isobutylamino). ) is shown. In pyrazine derivatives (), compounds in which R ₁ and R ₂ are both hydrogen atoms have the formula () A benzyl derivative and a 1,2-diamine derivative (in the formula, X has the same meaning as described above) dihydropyrazine derivative () which can be heated in a suitable organic solvent (e.g. ethanol) (wherein X has the same meaning as described above) with sulfur at 100 to 180°C. In the pyrazine derivative (), R ₁ is a hydrogen atom,
In the compound where R ₂ is a naphthylmethyl group and a substituted benzyl group having a halogen atom or a lower alkylamino group as a substituent, the dihydropyrazine derivative () is substituted with naphthaldehyde and a substituted benzaldehyde having a halogen atom or a lower alkylamino group as a substituent. It is produced by reacting. Furthermore, in the above formula (), the pyrazine derivative in which R ₁ is a hydrogen atom or a halogen atom, and R ₂ is a halogen atom, the pyrazine derivative () in which R ₁ and R ₂ are hydrogen atoms is replaced by permaleic acid. to obtain a mono- or di-N-oxide, which is then halogenated with phosphorus oxyhalide to produce a 2,3-diphenyl-4 (or 4,5-) halogenated pyrazine derivative. I can do it. Furthermore, in the above formula (), R ₁ is a hydrogen atom,
The pyrazine derivative in which R ₂ is a cyano group, carboxyl group or lower alkyloxycarbonyl group is the above-mentioned 2,3-diphenyl-4-chloropyrazine derivative () (in the formula, X has the same meaning as described above) and potassium cyanide are reacted in the presence of a palladium catalyst (for example, tetrakis(triphenylphosphine)palladium), R ₂ has a cyano group ()
is obtained. By alkaline hydrolysis of this compound, () in which R ₂ is a carboxyl group is obtained, and by further alkyl esterification, () in which R ₂ is a lower alkyloxycarbonyl group is obtained. Since the pyrazine derivative of the present invention has the effect of inhibiting platelet aggregation, it can be effectively used as a platelet aggregation inhibitor to prevent cerebral thrombosis and the like. Furthermore, the pyrazine derivative of the present invention has a cyclohexygenase inhibitory effect and can also be used as an anti-inflammatory agent.
The dosage is generally about 30 to 600 mg per day for adults;
It is preferable to administer the drug in 1 to 3 divided doses if necessary.
The method of administration can take any form suitable for administration, with oral administration being particularly preferred, although intravenous injection is also possible. The compound of the present invention may be formulated into tablets, powders, capsules, or granules either alone or mixed with pharmaceutical carriers or excipients in a conventional manner. Examples of carriers or excipients include calcium carbonate, calcium phosphate, starch, sucrose, lactose, talc, magnesium stearate, and the like. In addition to the solid formulations mentioned above, the compounds of the present invention can also be formulated into liquid formulations such as oily suspensions and syrups. The compound of the present invention can also be stabilized by inclusion with cyclodextrin. Next, the present invention will be explained in more detail with reference to Examples and pharmacological test examples. Example 1 2.57 g of 2,3-diphenyl-5,6-dihydropyrazine, 1.40 g of 0-chlorobenzaldehyde,
0.672 g of potassium hydroxide was dissolved in 20 ml of methanol, and the mixture was reacted under heating under reflux for 1 hour. Methanol was distilled off from the reaction mixture under reduced pressure, and 50 ml of water was added to the residue, which was extracted three times with ethyl acetate. The extracted organic layer was washed with water, dried over anhydrous sodium sulfate, and then the solvent was distilled off under reduced pressure. The obtained extraction residue was subjected to silica gel column chromatography, and a crude product was obtained from the fraction eluted with 8:1 of hexane and ethyl acetate. The crude product was recrystallized from a mixture of methanol and water to give 2,3-diphenyl-
5-(0-chlorobenzyl)pyrazine 2.633g (74
%) was obtained. Melting point 112-114℃. The physical property data of this product supports the structure of the following formula (). Elemental analysis value: (C ₂₃ H ₁₇ ClN ₂ ) Calculated value: C, 77.41; H, 4.80; N, 7.85 Actual value: C, 77.13; H, 4.81; N, 7.83 MASS (m/z): 356 (molecular Ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 4.42 (2H, s)
8.47 (1H, s) Example 2 Using 2,3-diphenyl-5,6-dihydropyrazine (2.57 g) and m-chlorobenzaldehyde (1.40 g), the melting point was 58-59°C (recycled from methanol and water) in the same manner as in Example 1. 2,3-diphenyl-5- as a colorless prismatic crystal of
(m-chlorobenzyl)pyrazine 3.338g (94%)
I got it. The physical property data of this product supports the structure of the following formula (). Elemental analysis: (C ₂₃ H ₁₇ ClN ₂ ) Calculated value: C, 77.41; H, 4.80; N, 7.85 Actual value: C, 77.35; H, 4.75; N, 7.80 MASS (m/z): 356 (molecular ion Peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 4.18 (2H, s),
8.40 (1H, s) Example 3 Using 2,3-diphenyl-5,6-dihydropyrazine (2.57 g) and p-chlorobenzaldehyde (1.40 g), the melting point was 105 to 106 °C (reproduced from isopropyl alcohol) in the same manner as in Example 1. 2,3-diphenyl-5-(p-chlorobenzyl)pyrazine 3.358 as colorless prismatic crystals of
g (94%) was obtained. The physical property data of this product supports the structure of the following formula (). Elemental analysis value: (C ₂₃ H ₁₇ ClN ₂ ) Calculated value: C, 77.41; H, 4.80; N, 7.85 Example: C, 77.54; H, 4.80; N, 7.86 MASS (m/z): 356 (molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 4.20 (2H, s),
8.40 (1H, s) Example 4 Using 2,3-diphenyl-5,6-dihydropyrazine (2.57 g) and p-bromobenzaldehyde (1.85 g), the same procedure as in Example 1 was performed to obtain a melting point of 100 to 101°C (recrystallized from methanol). 3.87 g (97%) of 2,3-diphenyl-5-(p-bromobenzyl)pyrazine was obtained as colorless needle-like crystals.
The physical property data of this product supports the structure of the following formula (). Elemental analysis value: ( _{C23H17BrN2 )} Calculated value: C, 68.83; H, 4.27; _N , 6.98 Actual value: C, 68.84; H, 4.24; N, 6.97 MASS (m/z): 401 (molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 4.23 (2H, s),
8.48 (1H, s) Example 5 Using 2,3-diphenyl-5,6-dihydropyrazine (2.57 g) and p-dimethylaminobenzaldehyde (1.49 g), the same procedure as in Example 1 was performed to obtain a melting point of 80-82°C (from methanol and water). recrystallization)
2,3-diphenyl-5 as a colorless prismatic crystal of
-(p-dimethylaminobenzyl)pyrazine3.36
g (92%) was obtained. The physical property data of this product supports the structure of formula (XI) below. Elemental analysis value: (C ₂₅ H ₂₃ N ₃ ) Calculated value: C, 82.16; H, 6.34; N, 11.50 Actual value: C, 82.14; H, 6.30; N, 11.50 MASS (m/z): 365 (molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 2.88 (6H, s),
4.12 (2H, s) 8.40 (1H, s) Example 6 2,3-diphenyl-5,6-dihydropyrazine (2.57g) and 1-naphthaldehyde (1.56g)
Using the same procedure as in Example 1, the melting point was 91-92.
3.30 g (89%) of 2,3-diphenyl-5-(1-naphthyl)methylpyrazine was obtained as colorless prismatic crystals at 2,30° C. (recrystallized from methanol and water). The physical property data of this product supports the structure of formula (XII) below. Element molecular value: (C ₂₇ H ₂₀ N ₂ ) Calculated value: C, 87.06; H, 5.41; N, 7.52 Actual value: C, 86.96; H, 5.43; N, 7.50 MASS (m/s): 372 (molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 4.70 (2H, s),
8.30 (1H, s) Example 7 2,3-bis(p-methoxyphenyl)pyrazine 1,4-dioxide (1.80 g, 5.6 mM) was mixed with phosphorus oxychloride (20 ml) and reacted under heating under reflux for 1 hour. After cooling, the reaction mixture was poured into ice water, and then made basic with potassium carbonate.
Extraction was performed with methylene chloride, and the solvent was distilled off to obtain a pale yellow extraction residue. The residue was subjected to silica gel column chromatography (Wakogel C-200, 32 g, solvent mixed solution of benzene-AcoEt). The first eluted substance was 1.50 g of 2,3-bis(p-methoxyphenyl)-5,6-dichloropyrazine (78
%) was obtained. 2,3-bis(p-methoxyphenyl)-5,6 as colorless needles when recrystallized from hexane.
-Dichloropyrazine was obtained. Melting point 120-121℃. The physical property data of this product supports the structure of the following formula (). Elemental analysis value: (C ₁₈ H ₁₄ Cl ₂ N ₂ O ₂ ) Calculated value: C, 59.85; H, 3.91; N, 7.76 Actual value: C, 60.02; H, 3.88; N, 7.79 MASS (m/s) : 360 (molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 3.77 (6H, s),
6.38 (4H, d, J = 7.5Hz), 7.43 (4H, d, J
=7.5Hz) Example 8 2,3-bis(p-methoxyphenyl)pyrazine dioxide (3.92 g, 12.7 mM) was mixed in 20 ml of phosphorus oxychloride and reacted under heating under reflux for 30 minutes. After cooling, the reaction mixture was poured into ice water and then made basic with potassium carbonate to precipitate a yellow-orange solid. This was collected by filtration and subjected to silica gel column chromatography (Wakogel C-200, 70g
Solvent: hexane-methylene chloride = 1:1) to give 2,3-bis(p-methoxyphenyl)-5-
2.82 g (76%) of chloropyrazine was obtained. melting point 127
~128℃ (pale yellow prismatic crystals, recrystallized from ethanol). The physical property data of this product supports the structure of the following formula (). Elemental analysis value: (C ₁₈ H ₁₅ ClN ₂ O ₂ ) Calculated value: C, 66.17; H, 4.63; N, 8.57 Actual value: C, 65.91; H, 4.63; N, 8.60 MASS (m/z): 326 (Molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 3.77 (6H, s),
6.77 (4H, d, J = 7Hz), 7.33 (2H, d, J =
7Hz), 7.37 (2H, d, J = 7Hz), 8.42 (1H,
s) Example 9 2,3-bis(p-methoxyphenyl)-5-
Chloropyrazine (3.27g, 10mM), potassium cyanide (975mg, 15mM), tetrakis(triphenylphosphine)palladium (580mg, 0.5mM)
A solution of anhydrous DMF (50 ml) was heated to reflux under an argon atmosphere for 4 hours. Distill the solvent under reduced pressure and add water (100ml)
is added, extracted with methylene chloride, and the solvent is distilled off to obtain a dark brown sticky substance. This was subjected to medium pressure silica gel chromatography ^* (column: Kieselgel60,
230-400 mesh, manufactured by Merck, 20mm x 200mm,
When attached to the solvent hexane-AcoEt=4-1), 2,
2.66 g (84%) of 3-bis(p-methoxyphenyl)-5-cyanopyrazine was obtained. Melting point 110-112℃
(Pale yellow needle crystals, recrystallized from methanol). The physical property data of this product supports the structure of the following formula (). *UVILOG ALPC-100 (Oyoi Spectroscopic Instruments Co., Ltd.) Elemental analysis value: (C ₁₉ H ₁₅ N ₃ O ₂ ) Calculated value: C, 71.91; H, 4.76; N, 13.24 Actual value: C, 71.89; H, 4.63 ;N, 13.27 MASS (m/z): 317 (molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 3.77 (6H, s),
6.80 (4H, d, J = 9Hz), 7.43 (2H, d, J =
9Hz), 7.45 (2H, d, J = 9Hz) 8.70 (1H,
s) IR (KBr) cm ^-1 : 2260 (C≡N) Example 10 2,3-bis(p-methoxyphenyl)-5-
20% cyanopyrazine (2.0g, 6.3mM) in methanol (40ml) and 1,4-dioxane (30ml)
After adding the sodium hydroxide solution, the mixture is heated under reflux for 4 hours. The solvent was distilled off under reduced pressure, neutralized by adding 5% hydrochloric acid solution, extracted with methylene chloride, and the solvent was distilled off to obtain a crude product. The crude product was recrystallized from ethanol to give 2,3-bis(p
2.07 g (95%) of pyrazine-5-carboxylic acid (methoxyphenyl) was obtained. Melting point 234-235℃. The physical property data of this product supports the structure of the following formula (). Elemental analysis value: (C ₁₉ H ₁₆ N ₂ O ₄ ) Calculated value: C, 67.85; H, 4.80; N, 8.33 Actual value: C, 67.69; H, 4.85; N, 8.34 MASS (m/z): 336 (Molecular ion peak) IR (KBr) cm ^-1 : 1690 Example 11 After adding concentrated sulfuric acid (0.1 ml) to a solution of 2,3-bis(p-methoxyphenyl)pyrazine-5-carboxylic acid (336 mg, 1 mM) in methanol (5 ml),
Heat to reflux for 3 hours. The solvent was distilled off under reduced pressure, water (15 ml) was added, and the mixture was neutralized with potassium carbonate, extracted with methylene chloride, and the solvent was distilled off to obtain a crude product. The crude product was recrystallized from methanol to obtain 320 mg (91%) of 2,3-bis(p-methoxyphenyl)pyrazine-5-carboxylic acid methyl ester as colorless needle crystals. Melting point 140-141℃. The physical property data of this product supports the structure of formula (XII) below. Elemental analysis value: (C ₂₀ H ₁₈ N ₂ O ₄ ) Calculated value: C, 68.56; H, 5.18; N, 8.00 Actual value: C, 68.40; H, 5.11; N, 7.93 MASS (m/z): 350 (Molecular ion peak) ¹ H-NMR (CDCl ₃ ) δ (ppm): 3.77 (6H, s),
3.97 (3H, s) 6.78 (4H, d, J=9Hz), 7.48
(4H, d, J=9Hz) 9.1 (1H, s) Pharmacological test example [Platelet aggregation inhibitory effect] After collecting 1/10 volume of 3.8% sodium citrate blood from a rabbit carotid artery, the blood is centrifuged to obtain platelet-rich plasma (PRP: 5 x 10 ⁵ cells/μ). Put 200μ of the PRP and 25μ of saline into a cuvette, set it on an aggregometer, and heat it at 37°C for 2 minutes to prepare an ethanol solution of the pyrazine derivative to be tested.
After adding 1.25μ and incubating for 3 minutes, an arachidonic acid solution or a collagen solution, which is an agent for inducing platelet aggregation, was added, and platelet aggregation was measured using an aggregometer (Hematotracer: Niko Bioscience Co., Ltd.). The 50% inhibitory concentrations for platelet aggregation induced by arachidonic acid (80 μM) or collagen (15 μg/ml) are shown in Table 1.
Acetylsalicylic acid was used as a comparative example. As shown in Table 1, the pyrazine derivatives of the present invention were found to have significant antiplatelet aggregation activity. Furthermore, it was confirmed that pyrazine derivatives according to the present invention not shown in Table 1 also have similar activities. In addition, the 50% inhibitory concentration in the table refers to the aggregation ability of platelets when the pyrazine derivative according to the present invention is not introduced, assuming that the aggregation ability of platelets is 100%.
It means the pyrazine derivative solution concentration required to control the concentration to 50%.

[Cyclooxygenase inhibitory effect]

Using a cannula from the rabbit carotid artery, collect 9 volumes of blood per 1 volume of 3.8% sodium enoate solution into a centrifuge tube. Obtain platelet-rich plasma by centrifugation. 77mM of 1/10 of platelet-rich plasma
After adding the EDTA solution and mixing well, centrifuge at 250 rpm for 10 minutes at room temperature. Discard the supernatant and dissolve the washing solution (sodium chloride 134mM, trisaminomethane 15mM, EDTA 1mM, D-glucose 5mM in distilled water, pH 7.4 with 1N hydrogen).
Resuspend the platelets in approximately 3 ml (adjusted to 3 ml) and centrifuge at 2000 rpm for 10 minutes at room temperature. Discard the supernatant, resuspend the precipitated platelets in 1/15M phosphate buffer at pH 8.0, and reduce the number of platelets to 6 to 8 x 105 ^.
Adjust to pcs/μ. The washed platelets thus obtained are used as a cyclooxygenase enzyme source. Place 3 μg of arachidonic acid and 0.2 μCi (1 μg) of ¹⁴ C-labeled arachidonic acid (toluene solution) in a test tube with a stopper.
Propylene glycol/ethanol mixture (1:
3 volumes) and evaporate the ethanol and toluene under nitrogen gas. Add 50μ of the sample solution, then add 500μ of washed platelets, and incubate at 37℃ for 3 minutes.
Let it react for a minute. While cooling on ice, add 3 drops of 0.5N hydrogen chloride to bring the pH to 2-3. Add 2 ml of ethyl acetate, shake and extract for 10 minutes, and centrifuge at 2500 rpm for 10 minutes at 4°C. Transfer the supernatant to a flask and concentrate, then remove the residue to 100μ
Dissolve it in ethanol and place it on a thin silica gel plate (Merck & Co., Ltd. 60F254). Developing solution (chloroform/methanol/acetic acid/
After developing about 18 cm with water = 90:8:1:0.8), prostaglandin E ₂ was extracted using a radiochromato scanner.
The sum of radioactivity of prostaglandin D ₂ and HHT was measured to determine inhibitory activity. The results are shown in Table 2.
In addition, it was confirmed that pyrazine derivatives according to the present invention not shown in Table 2 also have similar activities.

[Acute toxicity]

An acute toxicity test by oral administration was conducted using ICR male mice (5 weeks old). The LD ₅₀ values of the pyrazine derivatives of the present invention were all 300 mg/Kg or more, confirming high safety. [Effects of the Invention] According to the present invention, a novel pyrazine derivative and a pharmaceutical formulation containing the same are provided. The above-mentioned compounds of the present invention significantly inhibit platelet aggregation induced by arachidonic acid or collagen, thereby preventing diseases caused by platelet aggregation.
In particular, it can be used as a prophylactic agent for thrombosis involving platelet aggregation, such as myocardial infarction, ischemic attack after cerebral hemorrhage, and cerebral infarction. Furthermore, since the above-mentioned compound of the present invention has a cyclooxygenase inhibitory effect, it can also be used as an anti-inflammatory agent.

Claims (1)

[Claims] 1 General formula () ( _{wherein ,} represents a substituted benzyl group, carboxyl group or lower alkyloxycarbonyl group having a halogen atom or a lower alkylamino group. 2 General formula () (In the formula, X represents a hydrogen atom, a cyano group, or a lower alkoxy group, R ₁ represents a hydrogen atom or a halogen atom, and R ₂ represents a hydrogen atom, a halogen atom, a lower alkyl group, a cyano group, a naphthylmethyl group, etc.) A platelet aggregation inhibitor containing a pyrazine derivative having a substituted benzyl group, a carboxyl group, or a lower alkyloxycarbonyl group having a halogen atom or a lower alkylamino group. 3 General formula () ( _{wherein ,} represents a substituted benzyl group, carboxyl group, or lower alkyloxycarbonyl group having a halogen atom or a lower alkylamino group.