A 5,6-diphenylpyrazine-2-azacycle compound, a preparation method and application thereof

Abstract

The application discloses a 5,6-diphenylpyrazine-2-azacycle compound and a preparation method and application thereof. The 5,6-diphenylpyrazine-2-azacycle compound is synthesized by a more simple and economical method, and it is found through anti-platelet aggregation activity detection that the prepared 5,6-diphenylpyrazine-2-azacycle compound has excellent anti-platelet aggregation activity and small toxic side effect, and can be used as an active ingredient of an antithrombotic drug. In addition, the activity of the synthesized 5,6-diphenylpyrazine-2-azacycle compound is greatly influenced by chiral compounds, and the activity of an R-type compound is obviously greater than that of an S-type compound, so that the R-type compound can play a more excellent antithrombotic effect as an active ingredient of an IP receptor agonist or other antithrombotic drug.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical chemistry, specifically relating to a 5,6-diphenylpyrazine-2-aza-heterocyclic compound, its preparation method, and its application. Background Technology

[0002] Prostaglandin I2 (PGI2) is a member of the arachidic acid family of lipids and an antagonist of thromboxanes; reduced synthesis of PGI2 promotes thrombus formation. Activation of the PGI2 receptor (IP receptor) not only inhibits platelet-mediated aggregation but also has a strong vasodilatory effect. IP receptor agonists can treat diseases including pulmonary hypertension (PAH), arteriosclerosis obliterans, coronary artery disease, myocardial infarction, transient ischemic attack, angina pectoris, stroke, ischemia-reperfusion injury, restenosis, atrial fibrillation, intermittent claudication, Raynaud's phenomenon, varicose veins, thrombosis, diabetes, diabetic nephropathy, hypertension, hyperlipidemia, cerebral infarction, rheumatoid arthritis, and chronic obstructive pulmonary disease (COPD).

[0003] Currently marketed PGI2-type drugs generally suffer from problems such as short half-life, poor chemical stability, and significant side effects, resulting in poor efficacy. Therefore, it is essential to develop a non-endogenous PGI2-type IP receptor agonist with a long half-life, good chemical stability, higher selectivity, and fewer side effects. Summary of the Invention

[0004] In view of the above-mentioned prior art, the present invention provides a 5,6-diphenylpyrazine-2-aza-heterocyclic compound, its preparation method and application, so as to obtain an antithrombotic drug with good chemical stability, higher selectivity and fewer side effects.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is to provide a 5,6-diphenylpyrazine-2-aza-heterocyclic compound, the structural formula of which is shown in formula (I):

[0006]

[0007] Where R is

[0008] R 1 R 2 Each of the following is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, halogen-substituted C1-C6 alkyl groups, C1-C6 alkoxy groups, C1-C6 alkoxy-substituted C1-C6 alkyl groups, hydroxyl-substituted C1-C6 alkyl groups, C1-C6 alkylamino-substituted C1-C6 alkyl groups, di(C1-C6 alkyl)amino-substituted C1-C6 alkyl groups, or nitrile-substituted C1-C6 alkyl groups.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the structural formulas of 5,6-diphenylpyrazine-2-aza-heterocyclic compounds are shown in formula (II) or (III):

[0011]

[0012] Where R is

[0013] R 1 R 2 Each is independently selected from hydrogen atom, C1-C6 alkyl, C1-C6 alkoxy or C1-C6 alkoxy-C1-C6 alkyl.

[0014] Furthermore, R 1 R 2 Each is independently selected from either a hydrogen atom or a methyl group.

[0015] Furthermore, the R group is chirally linked to the nitrogen heterocycle.

[0016] Furthermore, the chirality of the R group after being linked to the nitrogen heterocycle is R-type.

[0017] Furthermore, the 5,6-diphenylpyrazine-2-aza-heterocyclic compound is one of the compounds having the following structural formula:

[0018]

[0019] This invention also discloses a method for preparing 5,6-diphenylpyrazine-2-aza-heterocyclic compounds, the method comprising the following steps:

[0020] S1: 5-Chloro-2,3-diphenylpyrazine, the compound shown in Formula IV, and a base are co-dissolved in an organic solvent and reacted at 100–200 °C for 8–48 h to obtain the compound shown in Formula V;

[0021]

[0022] S2: The compound shown in Formula V, the compound shown in Formula VI, the base and the catalyst are co-dissolved in an organic solvent under an ice bath, and the reaction is stirred for 30 to 45 minutes. Then the temperature is naturally raised to room temperature and the reaction is continued for 1 to 3 hours to obtain the compound shown in Formula VII.

[0023]

[0024] S3: Dissolve the compound shown in Formula VII in an organic solvent under ice bath conditions, add a reducing agent, stir the reaction for 30-45 min, then naturally heat to room temperature and continue the reaction for 1-3 h to obtain the compound shown in Formula VIII.

[0025]

[0026] S4: The compound shown in Formula VIII, tert-butyl bromoacetate, base and catalyst are dissolved in an organic solvent under ice bath conditions. The mixture is stirred for 30-45 min, then naturally heated to room temperature and the reaction is continued for 1-3 h to obtain the compound shown in Formula IX.

[0027]

[0028] S5: Dissolve the compound shown in Formula IX and LiOH in an organic solvent under ice bath conditions and react overnight to obtain the product.

[0029] This invention also discloses the application of 5,6-diphenylpyrazine-2-azaheterocyclic compounds in the preparation of antithrombotic drugs. The prepared compounds can be IP receptor agonist drugs. Furthermore, the 5,6-diphenylpyrazine-2-azaheterocyclic compounds are R-type chiral compounds.

[0030] The beneficial effects of this invention are:

[0031] This invention synthesizes 5,6-diphenylpyrazine-2-azaheterocyclic compounds using a simpler and more economical method. Antiplatelet aggregation activity assays revealed that the synthesized 5,6-diphenylpyrazine-2-azaheterocyclic compounds exhibit excellent antiplatelet aggregation activity with low toxicity, making them suitable as active ingredients in antithrombotic drugs. Furthermore, the chirality of the synthesized 5,6-diphenylpyrazine-2-azaheterocyclic compounds significantly affects their activity; the R-type compounds show significantly greater activity than the S-type compounds. Using the R-type compounds as active ingredients in antithrombotic drugs such as IP receptor agonists can achieve superior thrombotic prevention and treatment effects. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the embodiments. The embodiments of the present invention are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Any equivalent substitutions made in the art based on the content disclosed in the present invention shall fall within the protection scope of the present invention.

[0033] The structure of the compound was determined by nuclear magnetic resonance (NMR). 1 It can be determined by ¹H NMR or liquid chromatography-mass spectrometry (LC-MS).

[0034] AB Sciex 4500 liquid chromatography-mass spectrometry (LC-MS) system; nuclear magnetic resonance (NMR) system 1The H NMR (H2N) detector was a Bruker AVANCE-600. 1 ¹H NMR shifts (δ) are given in parts per million (ppm), the solvent is CDCl₃, the internal standard is tetramethylsilane (TMS), and the chemical shifts are expressed in 10⁻⁶ ppm. -6 (ppm) is given as the unit.

[0035] Example 1: Preparation of 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid

[0036]

[0037] Step 1: Preparation of 5,6-diphenyl-2-hydroxypyrazine

[0038]

[0039] Under nitrogen protection, bibenzoyl (31.0 g, 0.10 mol), aminoacetamide (13.0 g, 0.12 mol), and NaOH (7.00 g, 0.24 mol) were sequentially added to 1 L of methanol solvent. The mixture was heated under reflux for 4 h, and the reaction was monitored by LC-MS, indicating that the starting materials reacted completely. The reaction solution was cooled to 0 °C, and then 12.5 mL of 12N HCl solution was added dropwise. After stirring the reaction solution at room temperature for 30 min, 10 g of sodium bicarbonate and 130 mL of water were added. The reaction solution was filtered, and the solid was washed with a small amount of water and methanol, respectively. After vacuum drying, 22.0 g of a white solid (5,6-diphenyl-2-hydroxypyrazine) was obtained, with a yield of 88.7% and ESI-MS values ​​of m / z = 249.2 (M+H). + .

[0040] Step 2: Preparation of 5-chloro-2,3-diphenylpyrazine

[0041]

[0042] Under nitrogen protection, 22.6 g (0.9 mol) of 5,6-diphenyl-2-hydroxypyrazine was added to 200 mL of phosphorus oxychloride solvent. The mixture was heated to reflux, and the reaction was monitored by LC-MS until the reactants were completely reacted. The mixture was cooled to room temperature and rotary evaporated under reduced pressure. It was then extracted with ethyl acetate, washed successively with cooled sodium bicarbonate solution, water, and saturated brine, dried over sodium sulfate, filtered, and rotary evaporated to obtain crude 5-chloro-2,3-diphenylpyrazine as a gray solid. The crude solid was then slurried with ethyl acetate, filtered, and dried under vacuum to give 14.0 g of white solid (5-chloro-2,3-diphenylpyrazine), yield: 58.5%, ESI-MS: m / z = 267.2 (M+H). + .

[0043] Step 3: Preparation of (1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)methanol

[0044]

[0045] Under nitrogen protection, 5-chloro-2,3-diphenylpyrazine (532 mg, 2.00 mmol), potassium carbonate (414 mg, 3.00 mmol), and pyrrolidine-3-ol (261 mg, 3.00 mmol) were added to 10 mL of N-methylpyrrolidone (NMP). The mixture was heated to 120 °C and reacted for 48 h. The reaction was monitored by LC-MS until the reactants were completely reacted. The reaction mixture was cooled and ice water was added. The mixture was extracted with ethyl acetate. The organic mixed phase was washed with water and saturated brine, dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The mixture was then purified by silica gel column chromatography. The solid was collected under reduced pressure and dried under vacuum to give 522 mg of a white solid (1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-ol), yield: 82.3%, ESI-MS: m / z = 318.2 (M+H). + .

[0046] Step 4: Preparation of tert-butyl 2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)acetate

[0047]

[0048] Under ice bath conditions, 1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-ol (476 mg, 1.50 mmol), tetrabutylammonium bisulfate (510 mg, 1.50 mmol), and tert-butyl bromoacetate (438 mg, 2.25 mmol) were added sequentially to a mixture of 2.5 mL toluene and 2.5 mL 40% KOH. The mixture was stirred vigorously for 30 min, allowed to warm naturally to room temperature, and reacted for 2 h. Ice water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic mixed phase was washed with water and saturated brine, dried over MgSO4, filtered, solvent removed under reduced pressure, purified by silica gel column chromatography, collected under reduced pressure, and dried under vacuum to give 467 mg of a yellow oil (2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)tert-butyl acetate), yield: 72.2%, ESI-MS: m / z = 432.2 (M+H). + .

[0049] Step 5: Preparation of 2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethanol

[0050]

[0051] Under ice bath conditions, tert-butyl 2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)acetate (431 mg, 1.00 mmol) was dissolved in 10 mL of anhydrous tetrahydrofuran, and LiAlH4 (76.0 mg, 2.00 mmol) was slowly added in portions. The reaction was carried out for 30 min, and after naturally warming to room temperature, the reaction was carried out for another 2 h. The reaction was monitored by LC-MS and the starting material was completely reacted. After cooling the reaction solution to 0°C, the solution was slowly poured into a beaker containing solid sodium sulfate decahydrate under stirring. The mixture was stirred for 30 min, filtered, and the filtrate was subjected to reduced pressure to remove tetrahydrofuran. Ethyl acetate was added for extraction, followed by washing with water and saturated brine sequentially. The solution was dried over sodium sulfate, filtered, and the solvent was removed under reduced pressure. The solution was then purified by silica gel column chromatography, collected under reduced pressure, and dried under vacuum to obtain 350 mg of an oily substance (2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethanol), yield: 97.0%, ESI-MS: m / z = 362.2 (M+H). + .

[0052] Step 6: Preparation of tert-butyl 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetate

[0053]

[0054] Under ice bath conditions, add 2.5 mL of toluene and 2.5 mL of... Compound 2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethanol (361 mg, 1.00 mmol), tetrabutylammonium bisulfate (340 mg, 2.00 mmol), and tert-butyl bromoacetate (292 mg, 1.50 mmol) were added sequentially to a mixture of 40% KOH. The mixture was stirred vigorously for 30 min, allowed to warm naturally to room temperature, and reacted for 2 h. Ice water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic mixed phase was washed with water and saturated brine, dried over MgSO4, filtered, desolventized under reduced pressure, purified by silica gel column chromatography, collected under reduced pressure, and dried under vacuum to give 389 mg of a yellow oil (2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)tert-butyl acetate), yield: 81.9%, ESI-MS: m / z = 476.2 (M+H). + .

[0055] Step 7: Preparation of 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid

[0056]

[0057] Under ice bath conditions, 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)methoxy)ethoxy)tert-butyl acetate (238 mg, 0.50 mmol) and LiOH (48.0 mg, 2.00 mmol) were added sequentially to 2 mL of MeOH solution. The reaction was allowed to proceed overnight. Methanol was removed under reduced pressure. 5 mL of ice water and 5 mL of ethyl acetate were added to the reaction solution, and the pH was adjusted to 5-6 with 2N HCl. The mixture was extracted with ethyl acetate, washed with water and saturated brine, dried over MgSO4, filtered, solvent removed under reduced pressure, and purified by silica gel column chromatography. The purified solution was collected under reduced pressure and dried under vacuum to give 180 mg of a pale yellow oily liquid (2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid, yield: 86.0%, ESI-MS: m / z = 420.2 (M+H). + .

[0058] Example 2: Preparation of (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid

[0059]

[0060] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (R)-pyrrolidine-3-ol, yielding a yellow oily substance (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid; ESI-MS: m / z = 444.5 (M+H) + ; 1 H NMR (600MHz, CDCl3) δ7.94(s,1H),7.47–7.43(m,2H),7.35–7.31(m,2H),7.29–7.26(m,2H),7.26–7. 20(m,4H),4.35–4.32(m,1H),4.15(s,2H),3.82–3.68(m,8H),2.29–2.25(m,1H),2.21–2.17(m,1H).

[0061] Example 3: Preparation of (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid

[0062]

[0063] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (S)-pyrrolidine-3-ol, yielding a yellow oily (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-3-yl)oxy)ethoxy)acetic acid; ESI-MS: m / z = 444.5 (M+H) + ; 1 H NMR(600MHz, CDCl3)δ7.96(s,1H),7.44(dd,J=7.9,1.5Hz,2H),7.32(dd,J=7.8,1.6Hz,2H),7.30–7.27(m,2H),7.2 6–7.20(m,4H),4.34–4.29(m,1H),4.16(s,2H),3.81–3.66(m,8H),2.25(dd,J=15.2,9.6Hz,1H),2.20–2.12(m,1H).

[0064] Example 4: Preparation of 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)ethoxy)acetic acid

[0065]

[0066] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with pyrrolidine-2-methanol, yielding a yellow oily 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)ethoxy)acetic acid; ESI-MS: m / z = 444.5 (M+H) + .

[0067] Example 5: Preparation of (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)ethoxy)acetic acid

[0068]

[0069] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (S)-pyrrolidine-2-methanol, yielding a yellow oily (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)ethoxy)acetic acid; ESI-MS: m / z = 444.5 (M+H) + ; 1H NMR (600MHz, CDCl3) δ8.05 (s, 1H), 7.44–7.41 (m, 2H), 7.32 (dd, J=7.7, 1.7Hz, 2H ),7.27(dd,J=4.8,2.1Hz,1H),7.26–7.20(m,5H),4.40(d,J=3.1Hz,1H),4.13(s ,2H),3.79(dd,J=9.7,3.9Hz,1H),3.72–3.67(m,5H),3.54(dd,J=9.6,7.7Hz,1H ),3.48(dt,J=12.4,4.0Hz,1H),2.11(dd,J=11.3,4.3Hz,2H),2.07–2.02(m,2H).

[0070] Example 6: Preparation of (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)ethoxy)acetic acid

[0071]

[0072] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (R)-pyrrolidine-2-methanol, yielding a yellow oily (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)ethoxy)acetic acid; ESI-MS: m / z = 444.5 (M+H) + ; 1 H NMR(600MHz, CDCl3)δ8.04(s,1H),7.45–7.41(m,2H),7.33(dd,J=7.8,1.6 Hz,2H),7.30–7.26(m,2H),7.26–7.20(m,4H),4.46–4.37(m,1H),4.13(s, 2H),3.79(dd,J=9.7,3.9Hz,1H),3.74–3.65(m,6H),3.55(dd,J=9.5,7.7H z,1H),3.51–3.45(m,1H),2.11(dd,J=14.1,6.5Hz,2H),2.08–2.04(m,2H).

[0073] Example 7: Preparation of 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)2-methylpropoxy)acetic acid

[0074]

[0075] The synthesis steps are the same as those in Example 1, namely steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with pyrrolidine-2-methanol, and tert-butyl bromoacetate in step 4 of Example 1 is replaced with tert-butyl 2-bromo-2-methylpropionate, yielding a yellow oily 2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)2-methylpropoxy)acetic acid; ESI-MS: m / z = 462.2 (M+H) + .

[0076] Example 8: Preparation of (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)2-methylpropoxy)acetic acid

[0077]

[0078] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (S)-pyrrolidine-2-methanol, and tert-butyl bromoacetate in step 4 of Example 1 is replaced with tert-butyl 2-bromo-2-methylpropionate, yielding a yellow oily (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)2-methylpropoxy)acetic acid; ESI-MS: m / z = 462.2 (M+H) + . 1 H NMR (600MHz, CDCl3) δ7.94(s,1H),7.36(d,J=7.9Hz,2H),7.26(d,J=7.6Hz,2H),7.21-7.13(m,6H),4.27-4.21(m,1H),4.02(s,2H),3. 77(d,J=5.6Hz,1H),3.62–3.56(m,1H),3.37(dd,J=17.8,9.8Hz,3H),3.25(t,J=8.8Hz,1H),2.04–1.95(m,4H),1.11(d,J=8.8Hz,6H).

[0079] Example 9: Preparation of (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)2-methylpropoxy)acetic acid

[0080]

[0081] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (R)-pyrrolidine-2-methanol, and tert-butyl bromoacetate in step 4 of Example 1 is replaced with tert-butyl 2-bromo-2-methylpropionate, yielding a yellow oily (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methoxy)2-methylpropoxy)acetic acid; ESI-MS: m / z = 462.2 (M+H) + ; 1 HNMR(600MHz, CDCl3)δ8.01(s,1H),7.43(d,J=7.9Hz,2H),7.33(d,J=7.6Hz,2H),7.28-7.20(m,6H),4.34-4.28(m,1H),4.09(s,2H),3 .84(d,J=5.6Hz,1H),3.69–3.63(m,1H),3.44(dd,J=17.8,9.8Hz,3H),3.32(t,J=8.8Hz,1H),2.11–2.02(m,4H),1.18(d,J=8.8Hz,6H).

[0082] Example 10: Preparation of (R)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)-pyrrolidine-2-yl)propoxy)acetic acid

[0083]

[0084] Its synthesis steps 1 and 2 are the same as steps 1 and 2 in Example 1.

[0085] Step 3: Preparation of (R)-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methanol

[0086]

[0087] Under nitrogen protection, 5-chloro-2,3-diphenylpyrazine (5.0 g, 18.8 mmol), potassium carbonate (4.2 g, 30.1 mmol), and (R)-pyrrolidine-2-methanol (2.1 g, 20.7 mmol) were added to 100 mL of N-methylpyrrolidone (NMP). The mixture was heated to 100 °C and reacted for 48 h. The reaction was monitored by LC-MS until the reactants were completely reacted. The reaction mixture was cooled and ice water was added. The mixture was extracted with ethyl acetate. The organic mixed phase was washed with water and saturated brine, dried over MgSO4, filtered, and the solvent was removed under reduced pressure. The mixture was then purified by silica gel column chromatography, collected under reduced pressure, and dried under vacuum to give 6.213 g of (R)-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methanol, yield: 80.2%, ESI-MS: m / z = 332.2 (M+H). + .

[0088] Step 4: Preparation of (R)-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)formaldehyde

[0089]

[0090] (R)-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)methanol (2.1 g, 6.35 mmol) was added to a 50 mL round-bottom flask, followed by 32 mL of dichloromethane. After the compound was completely dissolved, Dysmart reagent (2.8 g, 6.35 mmol) was added to the reaction solution in two portions. The reaction mixture was stirred overnight at room temperature, and the reaction was assessed by TLC to determine if it was complete. After the reaction was complete, the reaction solution was extracted with ethyl acetate, and the product was separated by column chromatography to obtain 1.32 g of (R)-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)formaldehyde, yield: 63.0%, ESI-MS: m / z = 330.2 (M+H). + .

[0091] Step 5: Preparation of (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)ethyl acrylate

[0092]

[0093] (R)-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)formaldehyde (1620 mg, 4.9 mmol) was added to a 50 mL round-bottom flask, followed by 24.5 mL of dichloromethane. After the compound was completely dissolved, ethyl triphenylphosphine (2.056 g, 5.9 mmol) was added. The reaction was assessed by TLC to determine if it was complete. After the reaction was complete, a suitable amount of silica gel was added, and the dichloromethane was distilled off under reduced pressure. The dichloromethane was then purified by column chromatography to give 1.01 g of (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)ethyl acrylate, yield: 51.6%, ESI-MS: m / z = 400.2 (M+H). + .

[0094] Step 6: Preparation of (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propionate ethyl ester

[0095]

[0096] Compound (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)ethyl acrylate (1.0 g, 2.5 mmol) was added to a 50 mL round-bottom flask, followed by 12.5 mL of methanol. After dissolution, palladium on carbon (100 mg, 10%) was added under N2 protection. The N2 was then replaced with H2, and the mixture was stirred overnight at room temperature under an H2 atmosphere. The reaction was assessed for completeness by TLC. After complete reaction, the reaction solution was filtered through a seven-hole funnel to remove the palladium on carbon and washed with an appropriate amount of methanol. The solvent was removed by rotary evaporation under reduced pressure to obtain crude (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propionate, ESI-MS: m / z = 402.2 (M+H). + .

[0097] Step 7: Preparation of (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propanol

[0098]

[0099] Ethyl (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propionate (360 mg, 0.9 mol) was added to a 25 mL round-bottom flask, followed by 4.5 mL of anhydrous THF. Lithium aluminum hydride (0.72 mL, 1.8 mmol) was slowly added under an ice-water bath, and the mixture was stirred at room temperature for 3 hours. The reaction was assessed for completeness by TLC. After complete reaction, unreacted lithium aluminum hydride was quenched dropwise with deionized water until no more bubbles were produced. The reaction solution was filtered through a seven-hole funnel, washed with an appropriate amount of ethyl acetate, and the solvent was removed under reduced pressure to obtain crude (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propanol. ESI-MS: m / z = 360.2 (M+H) + .

[0100] Step 8: Preparation of (R)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propoxy)tert-butyl acetate

[0101]

[0102] Under ice bath conditions, (R)-3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propanol (320 mg, 0.89 mmol) was dissolved in 4.5 mL of toluene, followed by the addition of a phase transfer catalyst, tetrabutylammonium hydrogen sulfate (152 mg), and 4.5 mL of 40% KOH solution. After stirring for 30 minutes, tert-butyl bromoacetate (203 μL, 1.25 mmol) was added, and the reaction was continued at room temperature for 3 hours. The reaction was assessed for completeness by TLC. After complete reaction, the reaction solution was extracted with ethyl acetate, the solvent was removed by rotary evaporation, and the solution was purified by column chromatography to obtain 277 mg of (R)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propoxy)tert-butyl acetate, yield: 65.6%, ESI-MS: m / z = 474.2 (M+H). + .

[0103] Step 9: Preparation of (R)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)-pyrrolidine-2-yl)propoxy)acetic acid

[0104]

[0105] (R)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propoxy)acetic acid tert-butyl ester (280 mg, 0.6 mmol) was dissolved in 3 mL of methanol, and then LiOH·H₂O (252 mg, 6 mmol) was added. The mixture was stirred at room temperature for 12 hours. The reaction was assessed for completeness by TLC. After the reaction was complete, the pH of the reaction solution was adjusted to weakly acidic by adding an appropriate amount of 2N HCl solution. The solution was then extracted with ethyl acetate, and the solvent was removed by rotary evaporation under reduced pressure. The mixture was then purified by column chromatography to obtain 186 mg of a yellow oily (R)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)pyrrolidine-2-yl)propoxy)acetic acid, yield: 75.6%, ESI-MS: m / z = 418.2 (M+H). + . 1 H NMR(600MHz, CDCl3)δ7.82(s,1H),7.37(d,J=6.8Hz,2H),7.28(d,J=6.1Hz,2H),7.18-7.15(m,6H),4.01-3.96 (m,1H),3.83(m,2H),3.51(t,1H),3.45-3.33(m,3H),1.90-1.81(m,4H),1.77-1.68(m,2H),1.62-1.55(m,2H).

[0106] Example 11: Preparation of (S)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)-pyrrolidine-2-yl)propoxy)acetic acid

[0107]

[0108] The synthesis steps are the same as steps 1, 2, 3, 4, 5, 6, 7, and 8 in Example 10, except that (R)-pyrrolidine-2-methanol in step 3 of Example 10 is replaced with (S)-pyrrolidine-2-methanol, yielding a yellow oily (S)-2-(3-(1-(5,6-diphenylpyrazin-2-yl)-pyrrolidine-2-yl)propoxy)acetic acid; ESI-MS: m / z = 418.2 (M+H) + ; 1H NMR (600MHz, CDCl3) δ7.97(s,1H),7.42(d,J=7.7Hz,2H),7.31(d,J=7.4Hz,2H ),7.26(s,1H),7.26–7.18(m,5H),4.20(s,1H),4.01(s,2H),3.66(t,J=8.4Hz, 1H),3.58(t,J=6.1Hz,2H),3.50(dd,J=16.8,8.0Hz,1H),2.08–1.99(m,3H),1 .98–1.91(m,1H),1.87(d,J=8.5Hz,1H),1.76–1.66(m,2H),1.53–1.44(m,1H).

[0109] Example 12: Preparation of 2-(2-((1-(5,6-diphenylpyrazin-2-yl)-azacyclobutane-3-yl)oxy)ethoxy)acetic acid

[0110]

[0111] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with aziridine-3-ol, yielding a yellow oily 2-(2-((1-(5,6-diphenylpyrazin-2-yl)-aziridine-3-yl)oxy)ethoxy)acetic acid; ESI-MS: m / z = 406.2 (M+H) + ; 1 H NMR (600MHz, CDCl3) δ7.87 (s, 1H), 7.41–7.37 (m, 2H), 7.31 (s, 1H), 7.29 (dd, J = 5.3, 1.8Hz, 1H), 7.28–7.20 (m, 6H), 4. 54(d,J=4.5Hz,1H),4.38–4.33(m,2H),4.13(s,2H),4.09(dd,J=9.0,4.2Hz,2H),3.73(s,2H),3.65(d,J=4.2Hz,2H).

[0112] Example 13: Preparation of 2-(2-((1-(5,6-diphenylpyrazin-2-yl)-azacyclobutane-3-yl)methoxy)ethoxy)acetic acid

[0113]

[0114] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with aziridine-3-methanol, yielding a yellow oily 2-(2-((1-(5,6-diphenylpyrazin-2-yl)-aziridine-3-yl)methoxy)ethoxy)acetic acid; ESI-MS: m / z = 420.2 (M+H) + ; 1 H NMR(600MHz, CDCl3)δ7.84(s,1H),7.43–7.40(m,2H),7.34–7.27(m,4H),7.26–7.20(m,4H),4.29(ddd,J=9.6,8.2,4.6Hz,4H),4.1 6(s,2H),3.94(dd,J=8.3,5.2Hz,2H),3.77(dd,J=7.3,5.0Hz,2H),3.71(dd,J=5.5,3.2Hz,2H),3.10(ddd,J=12.6,7.5,5.4Hz,1H).

[0115] Example 14: Preparation of (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)-azacyclobutane-3-yl)methoxy)ethoxy)acetic acid

[0116]

[0117] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (R)-azacyclobutane-2-methanol, yielding a yellow oily (R)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)-azacyclobutane-3-yl)methoxy)ethoxy)acetic acid; ESI-MS: m / z = 420.2 (M+H) + ; 1 H NMR(600MHz, CDCl3)δ8.02(s,1H),7.33(dd,J=8.0,1.4Hz,2H),7.27–7.23(m,2 H),7.22–7.20(m,1H),7.19–7.15(m,5H),4.55(dt,J=12.4,6.3Hz,1H),4.11–4 .03(m,3H),3.98(dd,J=16.5,8.0Hz,1H),3.87(dd,J=10.3,4.1Hz,1H),3.82(d d,J=10.3,5.5Hz,1H),3.73–3.64(m,4H),2.43–2.37(m,1H),2.35–2.29(m,1H).

[0118] Example 15: Preparation of (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)-azacyclobutane-3-yl)methoxy)ethoxy)acetic acid

[0119]

[0120] The synthesis steps are the same as those in Example 1, specifically steps 1, 2, 3, 4, 5, 6, and 7, except that pyrrolidine-3-ol in step 3 of Example 1 is replaced with (S)-azacyclobutane-2-methanol, yielding a yellow oily (S)-2-(2-((1-(5,6-diphenylpyrazin-2-yl)-azacyclobutane-3-yl)methoxy)ethoxy)acetic acid; ESI-MS: m / z = 420.2 (M+H) + .

[0121] Preparation Example 1: Preparation of racemic 2-(3-(1-(5,6-diphenylpyrazin-2-yl)-pyrrolidine-2-yl)propoxy)acetic acid

[0122]

[0123] The mixture was prepared sequentially according to the methods disclosed in Examples 14 and 55 of patent CN02808977.4, yielding a yellow, oily racemic 2-(3-(1-(5,6-diphenylpyrazin-2-yl)-pyrrolidine-2-yl)propoxy)acetic acid, ESI-MS: m / z = 418.2 (M+H). + .

[0124] Experimental example: In vitro platelet aggregation test

[0125] 1. Experimental Objective

[0126] The antiplatelet aggregation activity of the compounds in this invention was evaluated by studying their inhibitory effect on ADP-induced platelet aggregation in vitro.

[0127] 2. Test materials

[0128] 2.1 Test Materials

[0129] Fully automated platelet aggregation analyzer (Talitaikang AG800); ADP (Sigma); DMSO, 0.9% sodium chloride injection, sodium hydroxide, blood collection tubes, etc.

[0130] 2.2 Laboratory Animals

[0131] Domestic rabbit, male, 2.1±0.2kg.

[0132] 2.3 Test Drug

[0133] Compounds of Examples 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14; compound of Preparation Example 1.

[0134] 3. Test methods

[0135] 3.1 Preparation of the test solution

[0136] Weigh each of the above test drugs and prepare a stock solution with a concentration of 200mM using DMSO. After fully dissolving and mixing, take the stock solution and add 0.9% sodium chloride injection to prepare a series of test solutions of different concentrations (0.64μM-2000μM).

[0137] 3.2 Preparation of PRP and PPP

[0138] Rabbit blood was collected in plastic centrifuge tubes and anticoagulated with 3.2% sodium citrate (the ratio of anticoagulant to whole blood was 1:9). The blood was centrifuged at 140g for 10 minutes, and the supernatant was carefully aspirated to obtain PRP. The remaining plasma was centrifuged at 2000g for 10 minutes, and the supernatant was obtained to obtain PPP.

[0139] 3.3 Preparation of ADP solution

[0140] Weigh out ADP and dissolve it in 0.9% sodium chloride injection to prepare ADP stock solution. Aliquot the stock solution into centrifuge tubes and store at -20°C. Reconstitute before use and dilute to 300 μM with 0.9% sodium chloride injection.

[0141] 3.4 Maximum Aggregation Rate Detection

[0142] After powering on the platelet aggregation analyzer, preheat for 30 minutes until the temperature reaches 37°C before starting the test. Place 270 μL of PRP and 30 μL of the test solution into the PRP cup of the double-cup, and place 300 μL of PPP into the PPP cup of the double-cup. The instrument will then begin the test. Calculate the maximum platelet aggregation rate induced by ADP at a concentration of 100 μM.

[0143] 4. Experimental Data Results

[0144] Table 1. Maximum platelet aggregation rate of the compounds in the examples and preparation examples.

[0145]

[0146] Compared with preparation example 1: *P<0.01

[0147] The above experimental results show that the compound of Preparation Example 1 had a maximum platelet aggregation rate of 14.7%, while the compounds of Examples 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, and 14 of this invention had a greater inhibitory effect on platelet aggregation than the compound of Preparation Example 1. Among them, the compounds of Examples 4, 6, 7, and 9 had a very large inhibitory effect on platelet aggregation. It is evident that the antiplatelet aggregation activity of the compounds of Examples 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, and 14 of this invention is significantly better than that of the compound of Preparation Example 1.

[0148] It will be apparent to those skilled in the art that various modifications and variations can be made to the compounds, compositions, and methods of the present invention without departing from the spirit or scope of the invention. Therefore, the present invention includes modifications and variations thereof, provided they are within the scope of the claims and their equivalents.

[0149] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A 5,6-diphenylpyrazine-2-aza-heterocyclic compound, characterized in that, The structural formulas of the 5,6-diphenylpyrazine-2-aza-heterocyclic compounds are shown in formula (II) or (III): ； Where R is or ; The R 1 R 2 Each is independently selected from either a hydrogen atom or a methyl group; the chirality of the carbon atom to which the R group is attached to the nitrogen heterocycle is... R type.

2. The 5,6-diphenylpyrazine-2-azacyclic compound according to claim 1, characterized in that: The 5,6-diphenylpyrazine-2-aza-heterocyclic compound is one of the compounds having the following structural formula: 、 、 、 。 3. The method for preparing the 5,6-diphenylpyrazine-2-aza-heterocyclic compound according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1: 5-Chloro-2,3-diphenylpyrazine, the compound shown in Formula IV, and a base are co-dissolved in an organic solvent and reacted at 100-200°C for 8-48 h to obtain the compound shown in Formula V; ， ； S2: The compound shown in Formula V, the compound shown in Formula VI, the base and the catalyst are co-dissolved in an organic solvent under an ice bath, and the mixture is stirred for 30-45 min. Then the mixture is naturally heated to room temperature and the reaction is continued for 1-3 h to obtain the compound shown in Formula VII. ， ； S3: Dissolve the compound shown in Formula VII in an organic solvent under ice bath conditions, add a reducing agent, stir the reaction for 30-45 min, then naturally heat to room temperature and continue the reaction for 1-3 h to obtain the compound shown in Formula VIII. ； S4: The compound shown in Formula VIII, tert-butyl bromoacetate, base and catalyst are dissolved in an organic solvent under ice bath conditions. The mixture is stirred for 30-45 min, then naturally heated to room temperature and the reaction is continued for 1-3 h to obtain the compound shown in Formula IX. ； S5: Dissolve the compound shown in Formula IX and LiOH in an organic solvent under ice bath conditions and react overnight to obtain the product.

4. The use of the 5,6-diphenylpyrazine-2-aza-heterocyclic compound as described in any one of claims 1 to 2 in the preparation of antithrombotic drugs.

5. The application according to claim 4, characterized in that: The antithrombotic drug is an IP receptor agonist.

6. The application according to claim 4, characterized in that: The 5,6-diphenylpyrazine-2-aza-heterocyclic compound is R Type chiral compounds.

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