Pirfenidone derivative, preparation method therefor, and use thereof

Abstract

Disclosed in the present invention are a pirfenidone derivative, a preparation method therefor, and a use thereof. The structural formula of the pirfenidone derivative is as shown in formula (I). In formula (I), R1, R2, R3, and R4 can be the same or different and are each independently selected from any of the following groups: -CH3, -CH2OH, -CH2NH2, -CF3, and -CH2NR5R6; and R5 and R6 can be the same or different and are independently selected from any of the following groups: -CH3 and -C2H5. Compared with pirfenidone, the compound has a superior lung function improvement effect and can meet the clinical requirements for treating pulmonary fibrosis (IPF).

Description

A pirfenidone derivative and its preparation method and application Technical Field

[0001] The present invention belongs to the field of medicine, and specifically relates to a pirfenidone derivative and a preparation method and application thereof. Background Art

[0002] IPF is a chronic interstitial lung disease of unknown etiology characterized by pathological changes similar to those of common interstitial pneumonia. It is the most common type of idiopathic interstitial pneumonia. IPF is most common in patients aged 40 to 70 years. While the precise incidence of IPF is unknown, it is estimated to be approximately 13 to 20 per 100,000 people, with an increasing incidence rate with age, reaching an average age of diagnosis of 66. The mortality rate also increases with age, with a higher rate in men than in women. The five-year survival rate is 20%, a mortality rate far higher than that of many cancers.

[0003] Combinations of corticosteroids with azathioprine and N-acetylcysteine ​​can treat mild to moderate pulmonary fibrosis. However, limited research, numerous side effects, and low clinical efficacy limit the use of these drugs. Recent studies have demonstrated that IPF is caused by chronic epithelial cell damage and abnormal fibrocyte activity. Consequently, the treatment of IPF has shifted from corticosteroids and immunosuppressants to antifibrotic drugs. Currently, no drug has been approved by the US FDA for the treatment of IPF.

[0004] Pirfenidone is an oral pyridine drug that can regulate many cytokines, including transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), and tumor necrosis factor (TNF-α), changing collagen expression, synthesis, and accumulation, inhibiting extracellular matrix proliferation and expression, and having anti-inflammatory, antioxidant, and anti-fibrotic effects.

[0005] Pirfenidone and nintedanib are the main drugs for the treatment of idiopathic pulmonary fibrosis. Their mechanisms of action are similar, targeting fibroblasts and myofibroblasts. However, there are still significant differences between the two:

[0006] 1. Different targets within target cells: Pirfenidone inhibits targets such as transforming growth factor-β, reducing cell proliferation, lowering the production of fibrosis-related proteins, and reducing the aggregation of inflammatory cells caused by stimulation. Nintedanib inhibits multiple tyrosine kinases, affecting intracellular signal transduction, thereby inhibiting the proliferation, migration, and transformation of fibroblasts.

[0007] 2. Differences in adverse reactions and therapeutic outcomes: A common adverse reaction for pirfenidone is elevated liver enzymes; for nintedanib, bronchitis and myocardial infarction are common. During treatment, nintedanib shedding is more common than for pirfenidone, while pirfenidone discontinuation rates are lower. In terms of stability, pirfenidone is more stable than nintedanib.

[0008] 3. Although both nintedanib and pirfenidone have been approved for the treatment of decreased lung function in IPF, neither has a clear advantage in reducing disease mortality.

[0009] Although existing drugs have shown some improvement in IPF, they still cannot meet clinical needs. Therefore, it is necessary to find more effective drugs to treat IPF.

[0010] Summary of the Invention

[0011] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a pirfenidone derivative that can meet clinical needs and has better effect in treating IPF.

[0012] The pirfenidone derivative provided by the present invention is a compound represented by formula (I) or a pharmaceutically acceptable salt, ester, solvate, or prodrug thereof:

[0013] In the formula (I), R1, R2, R3, and R4 may be the same or different and are independently selected from any of the following groups: -CH3, -CH2OH, -CH2NH2, -CF3, and -CH2NR5R6;

[0014] The R5 and R6 may be the same or different and independently selected from any of the following groups: -CH3, -C2H5.

[0015] Furthermore, the pharmaceutically acceptable salt of the compound represented by formula (I) may be any of the following salts: hydrochloride, nitrate, methanesulfonate, phosphate, citrate, fumarate, sulfate, succinate, tartrate, citrate, hydrobromide, hydroiodide, acetate, lactate, tosylate, cinnamate, salicylate, malonate, glutarate, and malate.

[0016] Specifically, the compound represented by formula (I) may be a compound represented by the following formula (II):

[0017] Furthermore, the pharmaceutically acceptable salt of the compound represented by formula (II) has the structural formula represented by formula (III):

[0018] The X is selected from the acid anions generated when any of the following acids are ionized: hydrochloric acid, nitric acid, methanesulfonic acid, phosphoric acid, citric acid, fumaric acid, sulfuric acid, succinic acid, tartaric acid, citric acid, hydrobromic acid, hydroiodic acid, acetic acid, lactic acid, toluenesulfonic acid, cinnamic acid, salicylic acid, malonic acid, glutaric acid, and malic acid.

[0019] The pharmaceutically acceptable salts of the compounds of formula (I) described in the present invention refer to salts that are suitable for contact with the tissues of humans and lower animals without causing excessive toxicity, irritation, allergic reactions, etc., and are commensurate with a reasonable effect / risk ratio within the scope of reliable medical judgment.

[0020] In addition, prodrugs based on the compound of formula I also fall within the scope of protection of the present invention. The prodrug is metabolized into the compound of formula I in the body to exert its pharmaceutical effect.

[0021] The present invention also provides a method for preparing the compound represented by the above formula (II).

[0022] The preparation method comprises the following steps:

[0023] 5-Methylpyridin-2(1H)-one, 2-chloro-3,5,6-trimethylpyrazine, cuprous iodide and anhydrous potassium carbonate are mixed in N,N-dimethylformamide and refluxed to obtain a compound represented by formula (II).

[0024] In the above method, the CAS number of the 5-methylpyridin-2(1H)-one is 1003-68-5, and the structural formula is as follows:

[0025] In the above method, the CAS number of the 2-chloro-3,5,6-trimethylpyrazine is 68303-35-5, and the structural formula is as follows:

[0026] In the above method, the molar ratio of 5-methylpyridin-2(1H)-one, 2-chloro-3,5,6-trimethylpyrazine, cuprous iodide and anhydrous potassium carbonate is 1:1:(0.1-0.5):(2-3).

[0027] In the above method, the reflux reaction conditions are: reflux reaction at 160° C. for 5 h.

[0028] The above method also includes the following steps: after the reflux reaction is completed, the reaction solution is concentrated, the residual solution is dissolved in dichloromethane, washed with water, and purified by column chromatography to obtain a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one.

[0029] The present invention also provides the use of the compound represented by the above formula (I) or its pharmaceutically acceptable salt, ester, or solvate in the preparation of a drug for preventing and / or treating pulmonary fibrosis.

[0030] The present invention also provides a medicine or pharmaceutical composition for preventing and / or treating fibrosis, comprising the compound represented by formula (I) as described above or a pharmaceutically acceptable salt, ester, or solvate thereof, and a pharmaceutically acceptable carrier.

[0031] The drug can be introduced into the body by oral administration, injection, spraying, penetration, absorption, physical or chemical mediation, such as muscle, intradermal, subcutaneous, intravenous, mucosal tissue; or introduced into the body after being mixed or encapsulated with other substances.

[0032] Preferably, the dosage form of the drug or pharmaceutical composition is an oral solid preparation or liquid preparation. The drugs in the above-mentioned various dosage forms can be prepared according to conventional methods in the pharmaceutical field.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The compound represented by formula (I) has a significant therapeutic effect on the bleomycin-induced mouse pulmonary fibrosis model. When compared at the same dose, ZONK2301-1 is more effective than pirfenidone in improving lung function indicators (pulmonary compliance) and alleviating the degree of lung tissue lesions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a synthetic route diagram of the compound represented by formula (II);

[0036] Figure 2 shows HE staining and Masson staining images of lung tissues of mice in the control group and model group. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with specific embodiments. The examples provided are only for illustrating the present invention and are not intended to limit the scope of the present invention. The examples provided below can serve as a guide for further improvements by those skilled in the art and are not intended to limit the present invention in any way.

[0038] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples, unless otherwise specified, were all commercially available.

[0039] Example 1, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one (ZONK2301-1)

[0040] 1) 2,3,5-Trimethylpyrazine 1-oxide

[0041] Dissolve 2,3,5-trimethylpyrazine (20.0 g, 0.164 mol) in acetic acid (100 mL) and heat to 80°C in an oil bath. Add sodium perborate tetrahydrate (38.0 g, 0.247 mol) portionwise and stir at this constant temperature for 20 h. Filter the insoluble material from the reaction solution, concentrate, and purify by column chromatography to obtain 2,3,5-trimethylpyrazine 1-oxide (18.3 g, 80.9%) as a yellow, transparent liquid. 1 H NMR(DMSO-d6 400MHz)δ9.24(s,1H),2.45(s,3H),2.34(s,6H).ESI-MS m / z:139.1[M+H] + .

[0042] 2) 2-Chloro-3,5,6-trimethylpyrazine

[0043] Phosphorus oxychloride (90 mL) and a catalytic amount of concentrated sulfuric acid were added to a three-necked round-bottom flask. The mixture was cooled to 10°C in an ice-water bath. 2,3,5-trimethylpyrazine 1-oxide (18.0 g, 0.130 mol) was added dropwise. After the addition was complete, the mixture was slowly heated to 100°C and stirred at this constant temperature for 20 hours. The reaction mixture was evaporated under reduced pressure, and the residue was poured into saturated aqueous sodium bicarbonate solution. The mixture was extracted with dichloromethane, concentrated, and purified by column chromatography to obtain 2-chloro-3,5,6-trimethylpyrazine (7.5 g, 37.0%) as a white solid. 1 HNMR(DMSO-d6 400MHz)δ2.56(s,3H),2.47(s,6H).ESI-MS m / z:157.6[M+H] + .

[0044] 3) 5-Methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one

[0045] 5-Methylpyridin-2(1H)-one (4.87 g, 44.7 mmol), 2-chloro-3,5,6-trimethylpyrazine (7.0 g, 44.7 mmol), cuprous iodide (0.85 g, 4.47 mmol), and anhydrous potassium carbonate (12.3 g, 89.4 mmol) were mixed in N,N-dimethylformamide (100 mL) and refluxed at 160°C for 5 h. The reaction solution was concentrated, and the residue was dissolved in dichloromethane, washed with water, and purified by column chromatography to obtain 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one (3.5 g, 34.2%) as a white solid. 1 H NMR (DMSO-d6 400MHz) δ7.96(s,1H),7.71(d,1H),7.03(d,1H),2.43(s,3H),2.32(d,3H),2.31(d,3H),2.25(d,3H).ESI-MS m / z:230.1[M+H]+.

[0046] Comparative Example 1, 5-methyl-1-(pyrazin-2-yl)pyridin-2(1H)-one (ZONK2301-2)

[0047] 5-Methylpyridin-2(1H)-one (2.86 g, 26.2 mmol), 2-chloropyrazine (3.0 g, 26.2 mmol), cuprous iodide (0.50 g, 2.62 mmol), and anhydrous potassium carbonate (7.23 g, 52.4 mmol) were mixed in N,N-dimethylformamide (50 mL) and refluxed at 160°C for 5 h. The reaction solution was concentrated, and the residual solution was dissolved in dichloromethane, washed with water, and purified by column chromatography to obtain 5-methyl-1-(pyrazin-2-yl)pyridin-2(1H)-one (1.98 g, 40.5%) as a white solid. 1 H NMR (DMSO-d6 400MHz) δ8.40-8.35(m,3H),7.05-6.55(m,3H),2.21(s,3H).ESI-MS m / z:188.1[M+H]+.

[0048] Example 2: Preparation of 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one hydrochloride

[0049] 5-Methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one (0.1 g, 0.44 mmol) was dissolved in ethyl acetate (10 mL). A 3 mmol / L solution of hydrogen chloride in ethyl acetate was added at room temperature to precipitate a solid, which was filtered and dried to obtain 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one hydrochloride (0.1 g, 86.3%) as a white solid. 1H NMR (DMSO-d6 400 MHz) δ 8.01 (s, 1H), 7.77 (d, 1H), 7.13 (d, 1H), 2.56 (s, 3H), 2.43 (d, 3H), 2.41 (d, 3H), 2.25 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0050] Example 3, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one nitrate

[0051] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one nitrate was prepared. H NMR (DMSO-d6 400 MHz) δ 8.05 (s, 1H), 7.78 (d, 1H), 7.15 (d, 1H), 2.55 (s, 3H), 2.43 (d, 3H), 2.40 (d, 3H), 2.26 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0052] Example 4, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one methanesulfonate

[0053] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one methanesulfonate was prepared. 1H NMR (DMSO-d6 400 MHz) δ 8.15 (s, 1H), 7.87 (d, 1H), 7.22 (d, 1H), 3.29 (s, 3H), 2.48 (s, 3H), 2.42 (d, 3H), 2.40 (d, 3H), 2.24 (d, 3H). ESI-MS m / z: 230.1 [M+H]+

[0054] Example 5, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one phosphate

[0055] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one phosphate was prepared. H NMR (DMSO-d6 400 MHz) δ 7.99 (s, 1H), 7.65 (d, 1H), 7.11 (d, 1H), 2.55 (s, 3H), 2.44 (d, 3H), 2.42 (d, 3H), 2.25 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0056] Example 6, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one citrate

[0057] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one citrate was prepared. 1H NMR (DMSO-d6 400 MHz) δ 7.97 (s, 1H), 7.56 (d, 1H), 7.13 (d, 1H), 3.38 (s, 1H), 2.76-2.63 (m, 4H), 2.56 (s, 3H), 2.42 (d, 3H), 2.40 (d, 3H), 2.22 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0058] Example 7, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one fumarate

[0059] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one fumarate was prepared. H NMR (DMSO-d6 400 MHz) δ 7.97 (s, 1H), 7.65 (d, 1H), 7.13 (d, 1H), 6.99 (d, 1H), 6.23 (d, 1H), 2.54 (s, 3H), 2.42 (d, 3H), 2.40 (d, 3H), 2.25 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0060] Example 8, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one sulfate

[0061] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one sulfate was prepared. H NMR (DMSO-d6 400 MHz) δ 8.11 (s, 1H), 7.85 (d, 1H), 7.23 (d, 1H), 2.55 (s, 3H), 2.45 (d, 3H), 2.41 (d, 3H), 2.18 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0062] Example 9, 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one succinate

[0063] According to the synthesis method of the salt in Example 2, a white solid 5-methyl-1-(3,5,6-trimethylpyrazin-2-yl)pyridin-2(1H)-one succinate was prepared. 1H NMR (DMSO-d6 400 MHz) δ 11.0 (s, 1H), 8.03 (s, 1H), 7.65 (d, 1H), 7.13 (d, 1H), 2.77-2.66 (m, 4H), 2.54 (s, 3H), 2.45 (d, 3H), 2.41 (d, 3H), 2.11 (d, 3H). ESI-MS m / z: 230.1 [M+H].

[0064] Example 10: Effects of Pirfenidone Derivatives on Bleomycin-Induced Pulmonary Fibrosis Model in Mice

[0065] 1. Test methods

[0066] Ninety-six SPF-grade BALB / c mice (half male and half female, weighing 18-22g) were randomly divided into two groups based on body weight: a normal control group (12 mice) and a model group (84 mice). The model group received a tail vein injection of 150mg / kg bleomycin at 20mL / kg to establish a mouse pulmonary fibrosis model. The normal control group received an equal volume of saline via the tail vein and was observed for 14 consecutive days. Before administration, two mice in each group were randomly selected for lung tissue pathological examination, which showed mild inflammatory cell infiltration in the alveoli and mild collagen fibrillation. Sixty model mice were selected and randomly divided into 6 groups according to sex and weight, namely, model control group, pirfenidone group (250 mg / kg, molar dose 1.35 mmol / kg), ZONK2301-1 low-dose group (154.5 mg / kg, molar dose 0.675 mmol / kg), ZONK2301-1 high-dose group (309 mg / kg, molar dose 1.35 mmol / kg), ZONK2301-2 low-dose group (126 mg / kg, molar dose 0.675 mmol / kg), and ZONK2301-2 high-dose group (252 mg / kg, molar dose 1.35 mmol / kg), with 10 animals in each group. Before administration, the test substance (ZONK2301-1 or ZONK2301-2) or the control substance (pirfenidone) was prepared in purified water to the appropriate concentration. Each group of mice was orally gavaged with the corresponding drug at 20 mL / kg once daily for 14 consecutive days. The normal control group and the model control group were orally gavaged with an equal volume of purified water. The day after the last dose, each group of mice was anesthetized with an intraperitoneal injection of Zotai 50 at 20 mL / kg. The trachea was exposed, and lung function parameters were measured using a pulmonary function testing system.

[0067] 2. Test results

[0068] 2.1 Model Confirmation

[0069] As shown in Figure 2, no abnormal changes such as inflammatory cell infiltration and collagen fibers were observed in the lung tissues of mice in the normal control group; mild inflammatory cell infiltration and mild collagen fibers were found in the alveoli of mice in the model group, indicating that the pulmonary fibrosis model was successfully established.

[0070] 2.2 Effects on lung function

[0071] As shown in Table 1, compared with the normal control group, the lung compliance (Cpyn), peak inspiratory flow rate (PIF), peak expiratory flow rate (PEF), tidal volume (Vt), forced vital capacity (FVC), forced expiratory volume in 0.1s (FEV 100) were significantly decreased (P≤0.05 or P≤0.01), and Penh (airway resistance) was significantly increased (P≤0.01); compared with the model control group, PIF, FVC, and FEV 100 The ZONK2301-2 and ZONK2301-2 low-dose and high-dose groups showed significantly better lung function improvement than the pirfenidone group (P≤0.05 or P≤0.01).

[0072] Table 1 Effects of ZONK2301 on lung function in model mice ( n=10)

Claims

1. A compound represented by formula (I) or a pharmaceutically acceptable salt, ester, solvate, or prodrug thereof: In the formula (I), R1, R2, R3, and R4 are the same or different and are independently selected from any of the following groups: -CH3, -CH2OH, -CH2NH2, -CF3, -CH2NR5R6; The R5 and R6 are the same or different and are independently selected from any of the following groups: -CH3, -C2H5.

2. The compound according to claim 1 or its pharmaceutically acceptable salt, ester, solvate, prodrug, characterized in that: The pharmaceutically acceptable salt of the compound represented by formula (I) is any of the following salts: hydrochloride, nitrate, methanesulfonate, phosphate, citrate, fumarate, sulfate, succinate, tartrate, citrate, hydrobromide, hydroiodide, acetate, lactate, toluenesulfonate, cinnamate, salicylate, malonate, glutarate, and malate.

3. The compound according to claim 1 or its pharmaceutically acceptable salt, ester, solvate, prodrug, characterized in that: The compound represented by the formula (I) is a compound represented by the following formula (II):

4. The compound according to claim 3 or its pharmaceutically acceptable salt, ester, solvate, prodrug, characterized in that: The pharmaceutically acceptable salt of the compound represented by formula (II) has the structural formula represented by formula (III): The X is selected from the acid anions generated when any of the following acids are ionized: hydrochloric acid, nitric acid, methanesulfonic acid, phosphoric acid, Citric acid, fumaric acid, sulfuric acid, succinic acid, tartaric acid, citric acid, hydrobromic acid, hydroiodic acid, acetic acid, lactic acid, benzenesulfonic acid, cinnamic acid, salicylic acid, malonic acid, glutaric acid, malic acid.

5. A method for preparing the compound of formula (II) according to claim 3, comprising the following steps: 5-Methylpyridin-2(1H)-one, 2-chloro-3,5,6-trimethylpyrazine, cuprous iodide and anhydrous potassium carbonate are mixed in N,N-dimethylformamide and subjected to reflux reaction to obtain a compound represented by formula (II).

6. The preparation method according to claim 5, characterized in that: The molar ratio of the 5-methylpyridin-2(1H)-one, 2-chloro-3,5,6-trimethylpyrazine, cuprous iodide and anhydrous potassium carbonate is 1:1:(0.1-0.5):(2-3); Alternatively, the reflux reaction conditions are: reflux reaction at 160° C. for 5 h.

7. The preparation method according to claim 5 or 6, characterized in that: The method further comprises the following steps: after the reflux reaction is completed, the reaction solution is concentrated, the residual solution is dissolved in dichloromethane, washed with water, and purified by column chromatography to obtain a white solid 5-methyl-1-(3,5,6-trimethylpyrazine-2-yl)pyridin-2(1H)-one.

8. Use of the compound represented by formula (I) in claim 1 or its pharmaceutically acceptable salt, ester, solvate or prodrug in the preparation of a drug for preventing and / or treating pulmonary fibrosis.

9. A medicine or pharmaceutical composition for preventing and / or treating pulmonary fibrosis, comprising the compound of formula (I) as claimed in claim 1 or a pharmaceutically acceptable salt, ester, solvate, prodrug thereof, and a pharmaceutically acceptable carrier.

10. The drug or pharmaceutical composition according to claim 9, characterized in that: The dosage form of the medicine or pharmaceutical composition is an oral solid preparation or a liquid preparation.

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