A dimer compound with endothelin A (ETA) receptor antagonist activity and its application

Abstract

This invention belongs to the field of medicinal chemistry, specifically relating to a dimeric compound with endothelin A (ETA) receptor antagonist activity and its applications. The compound of this invention is rapidly metabolized to atrasentan in human liver microsomes. In rats, after oral administration, it exhibits excellent absorption, high bioavailability, and a long half-life, significantly lowering blood pressure and improving kidney injury. Furthermore, its weak binding to P-GP and its non-substrate nature further enhance its bioavailability. The compound of this invention, or its pharmaceutically acceptable salt, holds promise for use in the preparation of drugs for the treatment and prevention of ETA receptor antagonist-related diseases, such as chronic kidney disease and hypertension.

Description

Technical Field

[0001] This invention belongs to the field of medicinal chemistry technology, specifically relating to a dimer compound with endothelin A (ETA) receptor antagonist activity and its applications. Background Technology

[0002] Endothelins are a class of bioactive polypeptide molecules synthesized and secreted by endothelial cells and acting on blood vessels and tissues. Among them, endothelin-1 (ET-1) is the most important and potent endogenous vasoconstrictor in the renal system. ET-1 binds to endothelin receptor A (ETA), leading to vasoconstriction and increased blood pressure. Long-term exposure can also cause damage to renal filtration function and pathological changes in renal tissue (such as glomerulosclerosis), representing one of the important pathological mechanisms in the development of these diseases. Therefore, the development of selective ETA receptor antagonists has become an important direction for the clinical treatment of these diseases.

[0003] Atrasentan, developed by Chinook Pharmaceuticals, is a selective endothelin A receptor (ETA) small molecule antagonist for the treatment of immunoglobulin A nephropathy (IgAN) and other proteinuric glomerular diseases. As a selective ETA receptor antagonist, it blocks ETA function with minimal impact on ETB receptors, providing beneficial renal effects, including vasodilation and anti-inflammatory effects, while still clearing ET-1. On April 2, 2025, the U.S. Food and Drug Administration (FDA) granted accelerated approval to Vanrafia® (atrasentan) for reducing proteinuria levels in adult patients with primary immunoglobulin A nephropathy (IgAN) at risk of rapid disease progression. This is the first and currently the only selective endothelin A receptor antagonist used to reduce proteinuria in primary IgA nephropathy (IgAN).

[0004]

[0005] Atrasentan

[0006] Although atrasentan, as the first selective ETA receptor antagonist for reducing proteinuria in primary IgA nephropathy, has demonstrated groundbreaking clinical value in the treatment of ETA receptor antagonism-related diseases, providing an effective intervention for vasoconstriction regulation and renal function protection, further improving the oral bioavailability of such drugs to optimize absorption efficiency, prolonging the in vivo half-life to maintain stable drug concentrations, and reducing the potential impact of efflux transporters on drug exposure in vivo, thereby more fully realizing the therapeutic potential of ETA receptor antagonism, remains an important direction for professionals in the field to continuously pursue drug performance optimization and improve clinical treatment outcomes. Summary of the Invention

[0007] In the clinical application of oral medications, bioavailability is one of the core indicators directly affecting therapeutic efficacy and user experience. It not only determines the absorption efficiency of a drug after oral administration but is also closely related to whether the drug can stably reach an effective therapeutic concentration and maintain a sustained therapeutic effect. This invention develops an ETA receptor antagonist-related compound with a novel structure that can further enhance bioavailability, to better meet the clinical need for long-term, stable, and highly effective treatment of ETA receptor antagonist-related diseases.

[0008] This invention provides a dimer compound or a pharmaceutically acceptable salt thereof having endothelin A (ETA) receptor antagonist activity, wherein the chemical structural formula of the dimer compound is:

[0009]

[0010] The present invention further provides a dimer compound having endothelin A (ETA) receptor antagonist activity or a pharmaceutically acceptable salt thereof, wherein the pharmaceutically acceptable salt is selected from the phosphate, camphor sulfonate, hydrochloride, hydrobromide, hydrofluoric acid, sulfate, nitrate, formate, acetate, propionate, oxalate, malonate, succinate, fumarate, maleate, lactate, malate, tartrate, citrate, picrate, methanesulfonate, trifluoromethanesulfonate, benzylsulfonate, and benzylsulfonate of the compound.

[0011] A second aspect of the present invention provides the use of the above-mentioned dimer compound having endothelin A (ETA) receptor antagonist activity or a pharmaceutically acceptable salt thereof, wherein the dimer compound or a pharmaceutically acceptable salt thereof is used in the preparation of a medicament for treating and / or preventing diseases related to endothelin A receptor antagonism.

[0012] Preferably, the disease includes chronic kidney disease and hypertension.

[0013] Preferably, the drug is a formulation made of an active ingredient and pharmaceutically acceptable excipients; the active ingredient is the aforementioned dimer compound with endothelin A (ETA) receptor antagonist activity or a pharmaceutically acceptable salt thereof. The pharmaceutically acceptable excipients possess certain physiological activity, but their addition does not alter the dominant role of the active ingredient in the disease treatment process; rather, they merely play an auxiliary role, which only assists in utilizing the known activity of the ingredient.

[0014] Beneficial effects

[0015] Compared with existing technologies, the compounds provided by this invention, especially compound 1, can be rapidly metabolized in human liver microsomes and completely converted into atrasentan with endothelin A (ETA) receptor antagonistic activity. In rats, after oral administration, the absorption effect is superior to atrasentan, with higher drug exposure and better bioavailability, and a longer half-life, which is more conducive to maintaining stable and sustained efficacy. In terms of pharmacodynamics, it can significantly reduce blood pressure in the Dahl / SS rat hypertension model, while also significantly improving the damage to renal filtration and excretion functions, and effectively alleviating pathological changes in renal tissue, thus protecting the kidneys. Furthermore, it was found that the compound has a weak affinity for P-glycoprotein (P-GP) and is not a substrate of P-GP, a characteristic that contributes to improved bioavailability. Attached Figure Description

[0016] Figure 1 This is the 1H NMR spectrum of compound 1.

[0017] Figure 2 This is the carbon NMR spectrum of compound 1. Detailed Implementation

[0018] The present invention is further illustrated below by means of examples. These examples are exemplary and intended to illustrate the problems and explain the present invention, and are not intended to be limiting. Unless otherwise specified, the raw materials and instruments used in the embodiments of the present invention are all commercially available conventional products.

[0019] Example 1: Synthesis of Compound A

[0020] In a dry three-necked reaction flask, atrasentan (110 mg, 1 equivalent) was dissolved in dry DMF. Under nitrogen protection, cesium carbonate (2 equivalents), potassium iodide (2 equivalents), and the chlorinated derivative (2 equivalents) were added sequentially. The reaction was allowed to proceed overnight at room temperature. The reaction was confirmed to be complete by TLC. The reaction was quenched with water, extracted three times with dichloromethane, and the organic phase was washed with water and saturated brine. After drying, the product was purified by silica gel column chromatography (PE:EtOAc 10:1 to 2:1) to give 127 mg of a pale yellow oily product, namely compound A, with a yield of 95%. 1H-NMR (600MHz, Methanol-d6) δH 0.8 (t, J= 7.3 Hz, 3H), 0.9 (t, J= 7.4 Hz, 3H), 1.1 (h,J= 7.4Hz, 2H), 1.3 (dq,J=7.4, 14.9 Hz, 3H), 1.4-1.4 (m, 1H), 1.5 -1.5 (m, 2H),2.1 (s, 3H), 2.8 (d. =13.6Hz, 1H),3.0-3.1 (m,1H),3.1-3.1 (m,3H),3.4 (dg,J=5.4.9.6 Hz, 2H).3.4-3.5(m.2H).3.6 (s,1H).38 (d J=9.6Hz 1H).3.8 (s,3H).4.7 (dJ= 14.0 Hz 1H).4.8-4.9 (m.2H)5.9-5.9 (m, 2H).6.7 (dJ=8.0 Hz 1H),6.8 (dd J=1.7.8.0 Hz 1H).6.9-6.9 (m.2H).7.0 (dJ=1.6 Hz,1H),7.3-7.3(m.2H); 13 C-NMR (100MHz, DMSO-d6) δ C 173.7, 171.7, 161.2, 153.5, 149.4, 147.8, 141.5, 139.5,135.0, 131.9, 130.4(Cx2), 121.5, 115.1(Cx2), 109.1, 108.3,102.3, 74.4, 62.9,61.6, 56.1, 55.7, 54.7, 48.2, 47.2, 46.4, 32.0, 30.7, 21.2, 20.9, 14.2, 14.2,9.1; LC-MS: [M+H] + =623.2783.

[0021]

[0022] Example 2, Synthesis of Compound 1

[0023] In a dry three-necked flask, atrasentan (2 equivalents) was dissolved in dry DMF. Under nitrogen protection, cesium carbonate (1 equivalent), potassium iodide (1 equivalent), and the chlorinated derivative (1 equivalent) were added sequentially. The reaction was allowed to proceed overnight at room temperature. TLC analysis confirmed complete reaction. The reaction was quenched with water, extracted three times with dichloromethane, and the organic phase was washed with water and saturated brine. After drying, silica gel column chromatography (PE:EtOAc 10:1 to 2:1) yielded 507 mg of a pale yellow oily product, compound 1, with a yield of 45%. The 1H NMR spectrum of compound 1 is shown below. Figure 1 As shown, the carbon NMR spectrum of compound 1 is as follows: Figure 2 As shown. LC-MS: [M+H]+=1130.5512.

[0024]

[0025] Example 3: Synthesis of Compound 2

[0026] In a dry three-necked reaction flask, atrasentan (2 equivalents) was dissolved in dry DMF. Under nitrogen protection, cesium carbonate (1 equivalent), potassium iodide (1 equivalent), and the bromide (1 equivalent) were added sequentially. The reaction was allowed to proceed overnight at room temperature. The reaction was confirmed to be complete by TLC. The reaction was quenched with water, extracted three times with dichloromethane, and the organic phase was washed with water and saturated brine. After drying, the mixture was purified by silica gel column chromatography (PE:EtOAc 10:1 to 2:1) to give 441 mg of a pale yellow oily product, namely compound 2, with a yield of 39%. LC-MS: [M+H]+ = 1122.5712.

[0027]

[0028] Experiment 1: Study of Compound Microparticles

[0029] (1) Experimental materials: Human liver microsomes were purchased from Rede Liver Disease Research (Shanghai) Co., Ltd. Reagents included DMSO, acetonitrile, formic acid, and propranolol (internal standard), all of which were commercially available. The instrument was Thermo Fisher LC-MS (U300 UPLC, TSQQUANTUMN ULTRA triple quadrupole mass spectrometer).

[0030] (2) Experimental methods: A certain amount of the compound was accurately weighed and dissolved in DMSO to prepare a 10 mM stock solution. The stock solution was diluted to 100 μM working solution with diluent (ACN:H2O = 1:1), and then diluted to 3 μM dosing solution with 0.1 M potassium phosphate buffer solution. 75 μL of liver microsomes were added to 925 μL of 0.1 M potassium phosphate buffer solution and mixed to obtain a 1.5 mg / mL liver microsome suspension, which was pre-incubated at 37 °C for 10 min. Samples were prepared at 0, 20 min and 60 min time points, and 150 μL of propranolol acetonitrile solution was added to each sample to terminate the reaction. All the above samples were centrifuged at 4000 rpm for 5 min, and 100 μL of the supernatant was added to 100 μL of ultrapure water and mixed before LC-MS / MS analysis. The LC-MS / MS detection conditions, including the chromatographic column and mobile phase, are as follows: Column: WaterSACQUITY™ PREMIER HSS T3, 50*2.1mm, 1.8um; Mobile phase: Water (0.1% formic acid) - acetonitrile, with gradient elution according to Table 1.

[0031] Table 1 Gradient elution conditions of the mobile phase

[0032]

[0033] Data processing: Taking the initial 0 point as 100%, the relative remaining content of the drug at each time point was calculated. Taking each time point of atrasentan as 100%, the relative amount of the compound in the example converted to atrasentan was calculated. The results are shown in Tables 2 and 3.

[0034] Table 2. Prototype changes of each drug in microsomes

[0035]

[0036] Table 3 shows the amount of atracentan converted from compound 1 in microsomes.

[0037]

[0038] The results showed that compound 1 was rapidly metabolized in human microsomes and could be completely converted into atrazotan.

[0039] Experiment 2: Pharmacokinetic Study of Compounds in Rats

[0040] (1) Experimental materials: Male SD rats, 200-300g, were purchased from Hangzhou Ziyuan Experimental Animal Technology Co., Ltd. (Animal License No.: SCXK (Zhejiang) 2024-0004). Reagents included DMSO, PEG-400, physiological saline, heparin, acetonitrile, formic acid, propranolol (internal standard), etc., all of which were commercially available. Instruments included Thermo Fisher LC-MS / MS (U300 UPLC, TSQ QUANTUMNULTRA triple quadrupole mass spectrometer).

[0041] (2) Experimental methods: The compound was weighed and dissolved in a DMSO-PEG-400-physiological saline (5:60:35, v / v / v) system. After administration to rats by gavage, 200 μL of venous blood was collected at 15 min, 30 min, 1 h, 2 h, 5 h, 7 h, and 24 h after administration and placed in heparinized EP tubes containing sodium fluoride. The tubes were centrifuged at 12000 rpm for 2 min, and the plasma was stored at -80℃ for later analysis. The test sample was dissolved in DMSO to a concentration of 2 mg / mL as a stock solution to prepare a series of standard solutions. Plasma samples of different concentrations were prepared to establish a standard curve. The plasma samples were processed and analyzed by LC-MS / MS. The detection conditions were the same as in Experiment 1.

[0042] (3) Data processing: After detecting blood drug concentration by LC-MS / MS, the pharmacokinetic parameters were calculated using WinNonlin 6.1 software and the non-compartmental model method. The results are shown in Table 4.

[0043] Table 4. Pharmacokinetic parameters of atrasentan and compound 1 in rats after gavage administration.

[0044]

[0045] Note: Dosage is converted to atracentan dosage.

[0046] The results showed that compound 1 had a higher exposure level in rats than the same dose of atrasentan, and its absorption and bioavailability were better than those of atrasentan after gavage administration.

[0047] Experiment 3: Antihypertensive effect and renal function evaluation of the test compound in a Dahl / SS rat model of hypertension.

[0048] (1) Experimental animals and experimental groups: Male Dahl / SS rats were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. After the adaptation period, the animals were randomly divided into 5 groups according to their baseline blood pressure and weight. The specific grouping and administration regimen are shown in Table 5.

[0049] Table 5. Experimental Animals and Experimental Groups

[0050]

[0051] (2) Experimental methods and results: After all animals were fed a 0.3% salt concentration diet and adapted to a non-invasive blood pressure monitor for one week, they were randomly divided into a normal control group, a model control group, and three drug-treated groups based on their blood pressure and body weight. The normal control group continued to be fed a 0.3% salt concentration diet, while the model control group and the three drug-treated groups were switched to an 8% salt concentration diet for 6 weeks. Drug administration was performed simultaneously with modeling, administered orally daily for 6 weeks. Blood pressure was measured at 1, 3, 7, and 24 hours after drug administration, and the area under the curve (AUC) was calculated. Serum creatinine was measured once before grouping and once at the experimental endpoint. Histopathological examination was performed on the kidneys of rats at the experimental endpoint. Measurement indicators are expressed as mean ± standard deviation. Data were entered and statistically analyzed using relevant software, and the results are shown in Tables 6, 7, and 8.

[0052] Table 6 Summary of statistical analysis results of the area under the systolic blood pressure curve (Mean±SD)

[0053]

[0054] Remark: * P ≤ 0.05 indicates that the difference is statistically significant compared with the normal control group. & P≤0.05 indicates that the difference is statistically significant compared with the model control group.

[0055] Table 7. Statistical analysis results of serum creatinine (Mean ± SD)

[0056]

[0057] Remark: * P ≤ 0.05 indicates that the difference is statistically significant compared with the normal control group. & P ≤ 0.05 indicates that the difference compared with the model control group is statistically significant.

[0058] Table 8. Summary of statistical analysis results of glomerular sclerosis scores in animal kidneys (Mean ± SD)

[0059]

[0060] Note: *P≤0.05 indicates a statistically significant difference compared to the normal control group, &P≤0.05 indicates a statistically significant difference compared to the model control group.

[0061] The results showed that, at doses of 10 mg / kg to 40 mg / kg, administration of compound 1 once daily during modeling had a significant antihypertensive effect, significantly improved renal filtration and excretion function, and significantly improved renal tissue pathological changes.

[0062] Experiment 4. Effect of the test compound on the binding affinity of P-glycoprotein (P-GP)

[0063] Experimental Methods and Results: First, the SDF format 3D structures of the test compound and atrasentan were downloaded from the PubChem database and imported into ChemBio3D Ultra 14.0 for energy minimization (MinimumRMS Gradient set to 0.001) and saved as mol2 format. Then, the optimized small molecule was imported into AutodockTools-1.5.6 for hydrogenation, charge calculation, charge allocation, and setting of rotatable bonds, and finally saved as "pdbqt" format. Simultaneously, P-GP (PDB ID: 3G5U) was downloaded from the PDB database, and PyMOL 2.3.0 was used to remove protein water of crystallization and original ligands. The processed protein structure was imported into AutoDockTools (v1.5.6) for hydrogenation, charge calculation, charge allocation, and specification of atom types, and saved as "pdbqt" format. Subsequently, POCASA 1.1 was used to predict protein binding sites, and AutoDockVina 1.1.2 was used for molecular docking (P-GP related parameters were set as follows: center_x=91.8, center_y=91.9, center_z=-45.4, search space size_x, size_y, and size_z were all 60, inter-grid spacing was 0.375 Å, exhaustiveness=10, and other parameters were default). PyMOL 2.3.0 was used to analyze the interaction modes of the docking results, and finally the molecular docking binding energies of different test compounds and atrasentan with P-GP were obtained. The results are shown in Table 9.

[0064] Table 9 Molecular docking binding energy

[0065]

[0066] The results showed that atrasentan had a stronger binding affinity to P-GP than compound 1, and compound 1 exhibited significantly improved bioavailability, which is related to the fact that compound 1 is not a substrate of P-GP. As an efflux transporter, P-GP actively pumps drugs out of intestinal epithelial cells or renal tubular cells if the drug is its substrate, leading to reduced drug absorption, decreased in vivo exposure, and ultimately, decreased bioavailability. Molecular docking experiments revealed that compound 1 has a weak affinity for P-GP and does not possess P-GP substrate properties, thus avoiding efflux by P-GP, reducing losses during drug absorption, and thereby promoting its improved bioavailability.

[0067] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A dimeric compound having an endothelin A (ETA) receptor antagonist effect or a pharmaceutically acceptable salt thereof, characterized by, The chemical structural formula of the dimer compound is: 。 2. The dimeric compound having an endothelin A (ETA) receptor antagonist effect or a pharmaceutically acceptable salt thereof according to claim 1, characterized by, The pharmaceutically acceptable salt is selected from the group consisting of phosphate, camphorsulfonic acid, hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, nitric acid, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid, malic acid, tartaric acid, citric acid, picric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzylsulfonic acid, benzenesulfonic acid.

3. Use of a dimeric compound having an endothelin A (ETA) receptor antagonistic effect according to claim 1 or a pharmaceutically acceptable salt thereof, characterized in that, The dimer compound or the pharmaceutically acceptable salt thereof is applied to preparation of a medicament for treating and / or preventing diseases related to endothelin A receptor antagonism.

4. Use according to claim 3, characterized in that, The diseases include chronic kidney disease, hypertension.

5. Use according to claim 3, characterized in that, The medicament is a preparation of an active ingredient and pharmaceutically acceptable adjuvants; the active ingredient is the dimer compound with endothelin A (ETA) receptor antagonism effect or the pharmaceutically acceptable salt thereof.

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