Piroctone derivatives as well as preparation method and application thereof

Abstract

The invention provides piroctone derivatives as well as a preparation method and application thereof, and belongs to the technical field of medicines. The piroctone derivative is novel in structure and has good solubility, and the preparation method is simple. Experiments prove that compared with a positive control drug DFO, the piroctone derivative provided by the invention has extremely strong iron ion chelating ability, has better anti-inflammatory, antibacterial, fibroblast migration promoting activity and diabetes refractory wound healing promoting activity, and can stabilize HIF-alpha. The piroctone derivative provided by the invention has a very good application prospect in the aspect of being developed into a novel iron chelating agent and an HIF-alpha stabilizer drug which have the effects of resisting inflammation, inhibiting bacteria, promoting wound healing, relieving iron overload and the like.

Description

Technical Field

[0001] This invention belongs to the field of medicinal chemistry technology, specifically relating to a class of pyrrolidone derivatives, their preparation methods, and applications. Background Technology

[0002] Iron chelators bind to iron ions to form stable complexes, preventing their catalytic activity in redox reactions and transferring Fe²⁺ ions to the body. Iron supply and control are crucial for various physiological processes, and iron chelators possess strong iron scavenging capabilities, exerting multiple functions by influencing iron homeostasis. Under normoxic conditions, prolyl hydroxylase (PHD) depends on iron ions (Fe²⁺). 2+ It catalyzes the hydroxylation of HIF-1α, promoting its degradation by the proteasome.

[0003] Iron chelators, such as deferoxamine methanesulfonate (DFO, trade name Desferal), inhibit PHD activity and block the degradation pathway of HIF-1α by chelating free iron ions, significantly upregulating its protein levels. This iron chelation mimics a hypoxic environment, activating the HIF-1α-mediated adaptive signaling pathway and promoting the expression of various downstream genes, thus exerting physiological functions: for example, by regulating the expression of angiogenesis-related factors (vascular endothelial growth factor, VEGF, and erythropoietin, EPO), promoting angiogenesis in diabetic wound healing; by regulating the expression of metabolic adaptation genes (glycolysis-related enzymes), enhancing cell survival under hypoxic or iron-deficient conditions; and by regulating the expression of anti-apoptotic proteins (members of the BCL-2 family), reducing oxidative stress-induced cell damage, etc.

[0004] DFO is a natural iron chelating agent containing hydroxamic acid groups that can specifically bind to ferric iron (Fe3+). 3+ It forms a stable water-soluble complex (ferricamine), which is excreted through urine (60%) and bile (40%). DFO affects Fe 3+ It exhibits high selectivity and strong affinity, preferentially scavenging free iron (NTBI) and iron in ferritin, but does not affect bound iron in hemoglobin, transferrin, or cytochrome. DFO is produced through fermentation by Streptomyces bacteria. Its half-life is 5-10 minutes, and the molecule contains three active hydroxamic acid groups, which can bind to ferric ions (Fe3+) through six coordination sites. 3 +) Forms stable chelates. Oral DFO absorption through the gastrointestinal tract is limited, requiring intramuscular, subcutaneous, or intravenous administration, which greatly restricts its widespread use. DFO treatment requires dynamic monitoring of serum ferritin, liver function, and hearing (due to potential ototoxicity), and dose adjustment to avoid hypoironemia. Furthermore, DFO has drawbacks such as poor water solubility and high cytotoxicity, making the search for safer and more effective alternative iron chelators of great significance.

[0005] Piroctone ketone is a compound with the chemical name 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone. Its ethanolamine salt form (pyroctone ketone ethanolamine salt, OCT) is widely used in the cosmetics industry to reduce dandruff by inhibiting the excessive proliferation of scalp fungi and regulating abnormal keratinocyte metabolism. Its targets include fungal cell membrane structure and metabolic enzyme activity. This invention uses pyroctone ketone as a lead compound, and through structural modification and optimized design, synthesizes a series of carboxylic acid (c) and aryl (b) derivatives, characterized by novel structures and low cytotoxicity. As a HIF-α stabilizer, it shows promising application potential in the preparation of novel iron chelating agents with anti-inflammatory, antibacterial, and wound-healing properties in diabetic patients. Summary of the Invention

[0006] The purpose of this invention is to provide a class of pyrrolidone derivatives, their preparation methods, and applications. This invention, through structural modification of pyrrolidone, yields a series of carboxylic acid (c) and aryl (b) compounds. The iron ion chelating agent provided by this invention has the advantages of novel structure, high solubility, and low cytotoxicity. As a HIF-α stabilizer, it shows promising application prospects in the preparation of novel iron chelating agents with anti-inflammatory, antibacterial, wound-healing, and iron-overload-reducing effects, as well as in the treatment of HIF-α stabilizer drugs such as those for renal anemia.

[0007] To achieve the above-mentioned objectives, the present invention employs the following technical solution: This invention provides a class of pyrrolidone derivatives, the structural formula of which is shown in formula (I): , Equation (I) Wherein R1 is selected from at least one of the following substituents: .

[0008] Furthermore, the pyrrolidone derivatives specifically include compounds 1c, 2c, 3c, 4c, 5c, 6b, 7b, 8b, 9b, 10b, 11b, 12b, 13b, 14b, 15b, 16b, 17b, 18b, 19b, 20b, 21b, 22b, 23b, 24b, and 25b, with the following structural formulas: .

[0009] Furthermore, the carboxylic acid (c) compounds and aryl (b) compounds provided by this invention have good solubility in water.

[0010] The present invention also provides a method for preparing the pyrrolidone derivative, comprising the following steps: The synthetic route for the carboxylic acid compounds 1c-5c includes the following steps: Using 6-bromo-2-pyridinecarboxylic acid as a starting material, the target compounds are obtained through a 6-step reaction. 6-bromo-2-pyridinecarboxylic acid is oxidized with oxytrifluoroacetic acid to give compound S2, which is then hydrolyzed in an aqueous potassium hydroxide solution to give 6-hydroxypyridine-2-carboxylic acid, i.e., S3. Further protection of the nitrogenous hydroxyl group with benzyl bromide yields benzyl-protected hydroxypyrrolidone, i.e., compound S4. Compound S4 is then reacted with glycine derivatives with different substitutions and β-alanine to obtain compounds 1a-5a. The benzyl groups protecting the carboxyl and hydroxyl groups are then removed by alkaline hydrolysis and acid hydrolysis, respectively, to obtain carboxylic acid compounds 1c-5c. Compounds 1c-5c are recrystallized from ethanol and used in biological experiments.

[0011]

[0012] The synthetic route of the aryl compounds 6b-25b includes the following steps: The aryl compounds are mainly synthesized by introducing benzylamine and aniline derivatives. The synthetic route is as follows: the benzyl-protected hydroxypyrrolidone acid, i.e., compound S4, is reacted with the arylamine derivative. First, the intermediate 6a-25a series of compounds are obtained by condensation reaction. Then, the benzyl group is removed by hydrolysis to obtain the final product 6b-25b.

[0013]

[0014] The present invention also provides the use of the pyrrolidone derivative in the preparation of anti-inflammatory drugs.

[0015] This invention also provides the application of pyrrolidone derivatives in the preparation of antibacterial drugs.

[0016] This invention also provides the use of pyrrolidone derivatives in the preparation of medicaments for treating diseases related to wound healing.

[0017] Furthermore, the diseases associated with wound healing include wounds caused by hyperglycemia, wounds caused by atherosclerosis and anemia, oral mucosal diseases, inflammatory wounds caused by bacterial infections, chronic wounds caused by foreign body residue, rheumatoid arthritis, systemic lupus erythematosus, pressure sores, burns, frostbite, surgical incision infections, and wounds caused by malignant tumors.

[0018] This invention also provides the application of pyrrolidone derivatives in the preparation of iron ion chelating agents to improve iron overload disease.

[0019] This invention also provides the application of pyrrolidone derivatives in the preparation of HIF-α stabilizers.

[0020] Compared with the prior art, the advantages and beneficial technical effects of the present invention are as follows: 1. Novel pyrrolidone derivatives were obtained through the technical solution of this invention. These compounds exhibit excellent water solubility and strong chelating effect on iron ions. In particular, compounds 1c, 3c, 7b, 8b, 10b, 13b, 14b, 15b, 16b, 17b, 21b, and 23b show superior chelating effects on iron ions compared to the existing positive control drug Deferoxamine Mesylate (DFO, EC). 50 =19.99±1.04 μM).

[0021] 2. All of the pyrrolidone derivatives have certain antibacterial effects. Compounds 11b, 12b, 13b, 14b, 15b, 16b, 17b, 18b, 20b, 23b, and 24b have better inhibitory activity against NO in RAW264.7 macrophages than the existing drug DFO. Compounds 11b, 17b, 8b, 22b, 23b, 14b, and 18b can stabilize HIF-α. Compounds 1c, 5c, 7b, 8b, 9b, 17b, and 19b have significant fibroblast migration-promoting activity.

[0022] 3. To improve the water solubility of 17b, esterification was performed using 2-octenylsuccinic anhydride (OSA, FDA-approved for food grade) in dichloromethane to modify 17b (utilizing the reactivity of the hydroxyl group). Further, self-assembling nanomicelles (17b-OSA@DSPE) were prepared by co-assembling with a PEGylated material (DSPE-PEG2000-NHS). Reactive oxygen species (ROS) release results showed that compounds 17b, 23b, 14b, and 15b significantly inhibited ROS release induced by high glucose in L929 cells. Furthermore, the inhibition rate of ROS release by 17b-OSA@DSPE was comparable to that of DFO. Pharmacodynamic results indicated that 17b-OSA@DSPE significantly promoted the healing of refractory diabetic wounds.

[0023] In summary, these pyrrolidone derivatives, as novel iron ion chelating agents, are very suitable for development into anti-inflammatory, antibacterial, and wound-healing drugs, and have great market application prospects. Attached Figure Description

[0024] Figure 1 Diagram of Piroctone and PHD2 molecular docking (PDB 3OUJ): Where, (A): Schematic diagram of Piroctone and PHD2 binding, the red spheres are Fe 2+ (B): Piroctone alkyl side chain folds inward (pink molecule), light blue protein is hydrophobic region, amino acid residues in pink region form hydrogen bonds with Piroctone; (C): Piroctone (light blue molecule) alkyl side chain extends outward. Figure 2 The results are for the anti-inflammatory activity of the compounds; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; Figure 3 The quantitative results of HIF-1α and HIF-2α in Hep3B liver cancer cells; Figure 4 Results of L929 cell scratch assay; Figure 5 Characterization results for 17b-OSA@DSPE: A: Macroscopic image of the nanomicelle dispersion; B: 1H NMR spectra of 17b and 17b-OSA (…). 1 C: TEM image of 17b-OSA@DSPE nanomicelles; D: Release rate of 22b-OSA@DSPE nanomicelles in the diabetic inflammatory microenvironment at pH 4–6; Figure 6 Results of intracellular reactive oxygen species (ROS) release experiments: A: Percentage of positive cells inhibited by the compound for ROS generation; B: Fluorescence density value of the compound inhibiting ROS generation; C: Percentage of positive cells inhibited by nanomicelles for ROS generation; D: Fluorescence density value of the nanomicelles inhibiting ROS generation. Figure 7 Results of 17b-OSA@DSPE promoting chronic wound healing in diabetic patients: A: Wound closure marks from day 0 to day 9 in different treatment groups; B: Wound healing curves in rats. Detailed Implementation

[0025] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the materials and reagents used can be purchased from biological or chemical reagent companies.

[0026] Based on the binding mode of proline hydroxylase (PHD) inhibitors to PHD and the structure of pyrrolidone, it is speculated that the high activity of pyrrolidone is due to the interaction of its carbonyl oxygen and nitrogen hydroxyl oxygen with the active site Fe. 2 ⁺ A bidentate coordination is formed. However, the function of the alkyl side chain of pyrrolidone is not yet clear. Based on this, molecular docking was used to discover that the present invention provides a molecular docking diagram of pyrrolidone and PHD2 as shown below. Figure 1 As shown, its combination mode is as follows Figure 1 As shown in (A), the carbonyl oxygen and nitrogen-hydroxyl oxygen complex with the divalent iron of the active center. When the carbonyl oxygen and nitrogen-hydroxyl oxygen adopt different complexation modes, such as Figure 1 (B) and Figure 1 As shown in (C), the alkyl side chain points to the inside or outside of the cavity.

[0027] According to the structure-activity relationship, when pyrrolidone adopts the inward binding mode of alkyl side chain, its alkyl side chain eventually points into the cavity. Therefore, it is chosen to shorten the alkyl side chain and introduce a carboxyl group at the end of the alkyl side chain to try to form a hydrogen bond with Arg138 to improve affinity. When the alkyl chain points outward, it forms a hydrophobic interaction with the hydrophobic amino acid in the hydrophobic cavity. Therefore, aryl side chains are used to replace alkyl side chains to enhance hydrophobic interactions and strengthen binding ability.

[0028] Example 1: Synthesis of intermediates 1.1 In a 500 mL single-necked round-bottom flask, 200 mL of 30% hydrogen peroxide and 40 mL of trifluoroacetic acid were added and stirred for 30 min in an ice bath. Then, 20 g (99 mmol) of 6-bromo-2-pyridinecarboxylic acid S1 was added in portions. After the addition was complete, the mixture was refluxed at 85 °C. The generated gas was treated with a saturated aqueous solution of sodium bicarbonate, and the reaction was monitored by TLC. The reaction was monitored every 24 h. If the starting material S1 was not completely consumed, 100 mL of 30% hydrogen peroxide solution was added after cooling until the starting material S1 was completely reacted. The reacted liquid was cooled, 1 L of ice water was added, and the mixture was allowed to stand to precipitate a white solid. The product S2 was obtained by filtration, and was a white solid with a yield of 76%. 1 H NMR (400 MHz, DMSO-) d 6) δ 8.28 (dd, J = 8.2, 2.0 Hz, 1H), 8.22 (dd, J = 7.9, 2.0Hz, 1H), 7.68 (t, J = 8.1 Hz, 1H).

[0029] 1.2 Add the S2 (0.5 g, 2.3 mmol) to a 50 mL round-bottom flask, dissolve it in 10 mL of 10% potassium hydroxide aqueous solution, reflux at 85 °C, and react for 48 h. Monitor the reaction; when the starting material is completely consumed, stop heating. Cool the reaction solution to room temperature, add 10% hydrochloric acid aqueous solution, and adjust the pH to 2. A solid precipitates; filter to obtain product S3, a white solid, with a yield of 65%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.41 (dd, J = 9.0, 7.0 Hz, 1H), 6.68 (dd, J = 9.0, 1.7 Hz, 1H), 6.60 (dd, J = 7.0, 1.7 Hz, 1H).

[0030] 1.3 The S3 (155 mg, 1 mmol) was added to a 50 mL round-bottom flask, dissolved in 10 mL of methanol, followed by the addition of potassium carbonate (207 mg, 1.5 mmol), and finally benzyl bromide (171 mg, 1 mmol). The mixture was refluxed at 85 °C for 12 h. After the reactants had reacted completely, 10% hydrochloric acid was added to adjust the pH to 2, resulting in the formation of a white solid. This solid was filtered to obtain product S4, a white solid, with a yield of 56%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.49 – 7.42 (m, 3H), 7.38 (dd, J = 4.9, 2.0 Hz, 3H), 6.70 (dd, J = 9.3, 1.7 Hz, 1H), 6.52 (dd, J = 6.8, 1.7 Hz, 1H), 5.24 (s, 2H).

[0031] Example 2: Synthesis of compounds 1a to 25a Compound 1a: Benzyl(1-(benzyloxy)-6-oxo-1,6-dihydropyridine-2-formyl)glycine ester The S4 (245 mg, 1 mmol, 1.0 eq) was added to a bottom flask and dissolved in anhydrous dichloromethane. EDCI (191 mg, 1 mmol, 1.0 eq) and HOBt (135 mg, 1 mmol, 1.0 eq) were then added, and the mixture was stirred until clear. Finally, glycine benzyl ester (165 mg, 1 mmol, 1.0 eq) was added. The reaction was monitored by TLC, and the reaction was complete after 6 h. The solution was diluted with water, extracted with dichloromethane, and the organic layer was washed with saturated NaCl solution, dried over anhydrous MgSO4, filtered, and concentrated under reduced pressure to obtain a yellow oily liquid. This was purified by column chromatography to obtain a white solid in 63% yield. 1 H NMR (400 MHz, DMSO- d 6) δ 9.34 (t, J = 6.0Hz, 1H), 7.51 – 7.43 (m, 1H), 7.47 – 7.40 (m, 2H), 7.39 – 7.26 (m, 8H), 6.66(dd, J = 9.3, 1.7 Hz, 1H), 6.27 (dd, J = 6.7, 1.7 Hz, 1H), 5.22 (s, 2H), 5.13(s, 2H), 4.07 (d, J= 5.9 Hz, 2H).

[0032] Compound 2a: Benzyl N-[(1-benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)-L-leucine ester] The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 73%. 1 H NMR (400MHz, DMSO- d 6) δ 9.32 (d, J = 7.8 Hz, 1H), 7.46 (dd, J = 9.3, 6.7 Hz, 1H), 7.42 (dd, J = 6.6, 3.0 Hz, 2H), 7.36 – 7.30 (m, 8H), 6.65 (dd, J = 9.3, 1.7Hz, 1H), 6.19 (dd, J = 6.7, 1.7 Hz, 1H), 5.26 – 5.15 (m, 2H), 5.09 (dd, J =8.1 Hz, 2H), 4.48 (ddd, J = 10.0, 7.7, 4.0 Hz, 1H), 1.66 – 1.45 (m, 3H), 0.81 – 0.72 (m, 6H).

[0033] Compound 3a: Benzyl N-[(1-benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)-L-phenylalanine ester] The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 78%. 1 H NMR (400MHz, DMSO- d 6) δ 9.42 (d, J = 7.8 Hz, 1H), 7.43 (dd, J = 9.3, 6.7 Hz, 1H),7.37 – 7.28 (m, 8H), 7.25 – 7.15 (m, 7H), 6.63 (dd, J = 9.3, 1.7 Hz, 1H), 5.99 (dd, J = 6.7, 1.7 Hz, 1H), 5.21 – 4.99 (m, 4H), 4.71 (ddd, J= 9.6, 7.7,5.5 Hz, 1H), 3.13 (dd, J = 13.9, 5.6 Hz, 1H), 2.97 (dd, J = 13.9, 9.7 Hz, 1H).

[0034] Compound 4a: benzyl N-[(1-benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)-L-valine ester] The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid in 80% yield. 1 H NMR (400MHz, DMSO- d 6) δ 9.26 (d, J = 8.1 Hz, 1H), 7.50 – 7.44 (m, 1H), 7.44 – 7.40(m, 2H), 7.40 – 7.25 (m, 8H), 6.64 (dd, J = 9.2, 1.7 Hz, 1H), 6.20 (dd, J =6.8, 1.7 Hz, 1H), 5.22 (d, J = 8.4 Hz, 1H), 5.17 (d, J = 8.4 Hz, 1H), 5.09(d, J = 1.7 Hz, 2H), 4.37 (dd, J = 8.1, 6.4 Hz, 1H), 2.08 (h, J = 6.7 Hz,1H), 1.24 – 1.10 (m, 1H), 0.82 (d, J = 6.8 Hz, 6H).

[0035] Compound 5a: benzyl-2-[1-(benzyloxy)-6-oxo-1,6-dihydropyridine-2-carbamate]-3-methylpentanoate The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 71%. 1 H NMR (400MHz, DMSO- d 6) δ 9.27 (d, J = 8.0 Hz, 1H), 7.45 (dd, J = 9.3, 6.7 Hz, 1H), 7.41 (p, J= 4.0, 3.3 Hz, 2H), 7.36 – 7.31 (m, 9H), 6.64 (dd, J = 9.3, 1.7Hz, 1H), 6.18 (dd, J = 6.8, 1.7 Hz, 1H), 5.25 – 5.12 (m, 2H), 5.09 (s, 2H), 4.39 (t, J = 7.4 Hz, 1H), 1.81 (s, 1H), 1.22 – 1.05 (m, 2H), 0.78 (d, J = 6.8Hz, 3H), 0.72 (t, J = 7.4 Hz, 3H).

[0036] Compound 6a: 1-(benzyloxy)-N-(4-methylbenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 72%. 1 H NMR (400MHz, DMSO- d 6) δ 9.33 (t, J = 6.0 Hz, 1H), 7.46 (dd, J = 9.3, 6.7 Hz, 1H),7.42 – 7.31 (m, 5H), 7.15 (d, J = 7.8 Hz, 2H), 7.01 (d, J = 7.8 Hz, 2H), 6.63(dd, J = 9.3, 1.7 Hz, 1H), 6.30 (dd, J = 6.7, 1.7 Hz, 1H), 5.20 (s, 2H), 4.36(d, J = 5.9 Hz, 2H), 2.23 (s, 3H).

[0037] Compound 7a: N-benzyl-1-(benzyloxy)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method was the same as that of compound 1a, except that a different amine was used, yielding a white solid with a yield of 59%. 1 H NMR (400MHz, DMSO- d 6) δ 9.38 (t, J= 6.1 Hz, 1H), 7.46 (dd, J = 9.3, 6.7 Hz, 1H),7.40 – 7.30 (m, 5H), 7.30 – 7.17 (m, 5H), 6.63 (dd, J = 9.3, 1.7 Hz, 1H), 6.33 (dd, J = 6.7, 1.7 Hz, 1H), 5.22 (s, 2H), 4.41 (d, J = 6.0 Hz, 2H).

[0038] Compound 8a: 1-(benzyloxy)-N-(4-bromobenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 67%. 1 H NMR (400MHz, DMSO- d 6) δ 9.41 (t, J = 6.1 Hz, 1H), 7.47 (dd, J = 9.3, 6.7 Hz, 1H),7.41 – 7.27 (m, 7H), 7.25 – 7.18 (m, 2H), 6.64 (dd, J = 9.3, 1.7 Hz, 1H), 6.33 (dd, J = 6.7, 1.7 Hz, 1H), 5.19 (s, 2H), 4.37 (d, J = 6.0 Hz, 2H).

[0039] Compound 9a: 1-(benzyloxy)-N-(4-methoxybenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 63%. 1 H NMR (400MHz, DMSO- d 6) δ 9.32 (t, J = 6.0 Hz, 1H), 7.45 (dd, J = 9.3, 6.7 Hz, 1H), 7.34 (d, J = 3.3 Hz, 5H), 7.23 – 7.13 (m, 2H), 6.78 – 6.70 (m, 2H), 6.62 (dd,J = 9.3, 1.6 Hz, 1H), 6.29 (dd, J = 6.7, 1.7 Hz, 1H), 5.20 (s, 2H), 4.33 (d, J = 6.0 Hz, 2H), 3.68 (s, 3H).

[0040] Compound 10a: 1-(benzyloxy)-N-(3,5-dimethoxybenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 68%. 1 H NMR (400MHz, DMSO- d 6) δ 9.35 (t, J = 6.0 Hz, 1H), 7.47 (dd, J = 9.3, 6.7 Hz, 1H), 7.36 (d, J = 1.9 Hz, 1H), 7.35 – 7.26 (m, 4H), 6.64 (dd, J = 9.3, 1.7 Hz, 1H), 6.45 (d, J = 2.3 Hz, 2H), 6.37 – 6.29 (m, 2H), 5.21 (s, 2H), 4.37 (d, J = 6.0 Hz, 2H), 3.60 (s, 6H).

[0041] Compound 11a: 1-(benzyloxy)-N-(3,5-dichlorobenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 71%. 1 H NMR (400MHz, DMSO- d 6) δ 9.43 (t, J = 6.0 Hz, 1H), 7.61 – 7.44 (m, 2H), 7.40 – 7.21(m, 7H), 6.65 (dd, J = 9.2, 1.7 Hz, 1H), 6.37 (dd, J = 6.7, 1.7 Hz, 1H), 5.19(s, 2H), 4.43 (d, J = 6.0 Hz, 2H).

[0042] Compound 12a: 1-(benzyloxy)-N-(4-chlorobenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method was the same as that of compound 1a, except that a different amine was used, yielding a white solid with a yield of 51%. 1 H NMR (400MHz, Chloroform-d) δ 7.49 (t, J = 5.9 Hz, 1H), 7.40 – 7.26 (m, 4H), 7.23 –7.13 (m, 5H), 6.57 (dd, J = 9.3, 1.7 Hz, 1H), 6.49 (dd, J = 6.8, 1.7 Hz, 1H), 5.18 (s, 2H), 4.45 (d, J = 5.9 Hz, 2H).

[0043] Compound 13a: 1-(benzyloxy)-N-(3,5-difluorobenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 78%. 1 H NMR (400MHz, DMSO- d 6) δ 9.42 (t, J = 6.1 Hz, 1H), 7.47 (dd, J = 9.3, 6.7 Hz, 1H),7.39 – 7.25 (m, 5H), 7.07 (tt, J = 9.4, 2.4 Hz, 1H), 7.02 – 6.93 (m, 2H), 6.65 (dd, J = 9.3, 1.6 Hz, 1H), 6.39 (dd, J = 6.7, 1.7 Hz, 1H), 5.20 (s, 2H), 4.44 (d, J = 6.0 Hz, 2H).

[0044] Compound 14a: 1-(benzyloxy)-N-(3-chlorobenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 75%. 1 H NMR (400MHz, DMSO- d 6) δ 9.39 (t, J= 6.0 Hz, 1H), 7.47 (dd, J = 9.3, 6.7 Hz, 1H),7.40 – 7.18 (m, 10H), 6.64 (dd, J = 9.3, 1.7 Hz, 1H), 6.34 (dd, J = 6.7, 1.7Hz, 1H), 5.20 (s, 2H), 4.42 (d, J = 6.0 Hz, 2H).

[0045] Compound 15a: 1-(benzyloxy)-N-(4-fluorobenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method was the same as that of compound 1a, except that a different amine was used, yielding a white solid with a yield of 69%. 1 H NMR (400MHz, DMSO- d 6) δ 9.37 (t, J = 6.0 Hz, 1H), 7.46 (dd, J = 9.3, 6.7 Hz, 1H),7.42 – 7.31 (m, 5H), 7.31 – 7.24 (m, 2H), 7.06 – 6.95 (m, 2H), 6.63 (dd, J =9.3, 1.7 Hz, 1H), 6.32 (dd, J = 6.7, 1.7 Hz, 1H), 5.20 (s, 2H), 4.39 (d, J =6.0 Hz, 2H).

[0046] Compound 16a: 1-(benzyloxy)-N-(3,5-dichlorophenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 64%. 1 H NMR (400MHz, DMSO- d 6) δ 11.15 (s, 1H), 7.67 (d, J = 1.8 Hz, 2H), 7.53 (dd, J = 9.3,6.7 Hz, 1H), 7.39 – 7.34 (m, 3H), 7.30 (dtdd, J= 6.0, 4.4, 3.1, 1.3 Hz, 3H),6.73 (dd, J = 9.3, 1.7 Hz, 1H), 6.52 (dd, J = 6.7, 1.7 Hz, 1H), 5.25 (s, 2H).

[0047] Compound 17a: N-(2,4,6-trimethylphenyl)-1-(benzyloxy)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid in 65% yield. 1 H NMR (400MHz, DMSO- d 6) δ 10.14 (s, 1H), 7.53 (dd, J = 9.3, 6.7 Hz, 1H), 7.44 (dd, J =6.7, 3.0 Hz, 2H), 7.35 (dd, J = 4.9, 1.9 Hz, 3H), 6.88 (s, 2H), 6.69 (dd, J =9.3, 1.6 Hz, 1H), 6.48 (dd, J = 6.7, 1.7 Hz, 1H), 5.26 (s, 2H), 2.21 (s, 3H), 2.05 (s, 6H).

[0048] Compound 18a: 1-(benzyloxy)-6-oxo-N-phenyl-1,6-dihydropyridine-2-carboxamide The synthesis method was the same as that of compound 1a, except that a different amine was used, yielding a white solid with a yield of 59%. 1 H NMR (400MHz, DMSO- d 6) δ 10.86 (s, 1H), 7.69 – 7.62 (m, 2H), 7.52 (dd, J = 9.3, 6.7Hz, 1H), 7.42 – 7.36 (m, 3H), 7.34 (d, J = 8.0 Hz, 2H), 7.32 – 7.23 (m, 3H), 7.17 – 7.08 (m, 1H), 6.70 (dd, J = 9.3, 1.7 Hz, 1H), 6.49 (dd, J= 6.7, 1.7Hz, 1H), 5.27 (s, 2H).

[0049] Compound 19a: 1-(benzyloxy)-N-(3,5-dimethoxyphenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid in 55% yield. 1 H NMR (400MHz, DMSO- d 6) δ 10.80 (s, 1H), 7.51 (dd, J = 9.3, 6.7 Hz, 1H), 7.39 (dd, J =7.7, 1.9 Hz, 2H), 7.30 (qd, J = 8.7, 7.5, 3.5 Hz, 3H), 6.89 (d, J = 2.3 Hz, 2H), 6.69 (dd, J = 9.3, 1.7 Hz, 1H), 6.46 (dd, J = 6.8, 1.7 Hz, 1H), 6.30 (t, J = 2.3 Hz, 1H), 5.26 (s, 2H), 3.70 (s, 6H).

[0050] Compound 20a: 1-(benzyloxy)-N-(3,5-difluorophenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method was the same as that of compound 1a, except that a different amine was used, yielding a white solid with a yield of 61%. 1 H NMR (400MHz, DMSO- d 6) δ 11.21 (s, 1H), 7.53 (dd, J = 9.3, 6.7 Hz, 1H), 7.41 – 7.25(m, 7H), 7.03 (tt, J = 9.3, 2.4 Hz, 1H), 6.73 (dd, J = 9.3, 1.7 Hz, 1H), 6.52(dd, J = 6.7, 1.7 Hz, 1H), 5.25 (s, 2H).

[0051] Compound 21a: 1-(benzyloxy)-N-(2-bromophenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 68%. 1 H NMR (400MHz, DMSO- d 6) δ 10.58 (s, 1H), 7.73 – 7.65 (m, 1H), 7.58 – 7.45 (m, 2H), 7.45– 7.38 (m, 3H), 7.36 (q, J = 3.6 Hz, 3H), 7.22 (td, J = 7.7, 1.7 Hz, 1H), 6.71 (dd, J = 9.3, 1.7 Hz, 1H), 6.50 (dd, J = 6.7, 1.7 Hz, 1H), 5.28 (s, 2H).

[0052] Compound 22a: 1-(benzyloxy)-N-(2,4-dimethylphenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 78%. 1 H NMR (400MHz, DMSO- d 6) δ 10.22 (s, 1H), 7.52 (dd, J = 9.3, 6.7 Hz, 1H), 7.43 (dd, J =6.8, 2.9 Hz, 2H), 7.35 (dd, J = 5.1, 1.9 Hz, 3H), 7.21 (d, J = 8.0 Hz, 1H), 7.04 (d, J = 2.1 Hz, 1H), 7.00 (dd, J = 8.0, 2.1 Hz, 1H), 6.68 (dd, J = 9.3, 1.7 Hz, 1H), 6.49 (dd, J = 6.7, 1.7 Hz, 1H), 5.26 (s, 2H), 2.24 (s, 3H), 2.09 (s, 3H).

[0053] Compound 23a: 1-Hydroxy-N-(4-methoxyphenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 74%. 1 H NMR (400MHz, DMSO- d 6) δ 10.71 (s, 1H), 7.61 – 7.54 (m, 2H), 7.51 (dd, J = 9.3, 6.7Hz, 1H), 7.39 (dd, J = 7.4, 2.0 Hz, 2H), 7.31 (td, J = 5.8, 5.1, 2.9 Hz, 3H), 6.97 – 6.88 (m, 2H), 6.68 (dd, J = 9.3, 1.6 Hz, 1H), 6.46 (dd, J = 6.7, 1.7Hz, 1H), 5.27 (s, 2H), 3.72 (s, 3H).

[0054] Compound 24a: 1-(benzyloxy)-6-oxo-N-phenethyl-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 67%. 1 H NMR (400MHz, Chloroform- d ) δ 7.38 – 7.31 (m, 5H), 7.29 – 7.22 (m, 4H), 7.16 – 7.08(m, 2H), 6.82 (t, J = 5.7 Hz, 1H), 6.68 (dd, J = 9.2, 1.7 Hz, 1H), 6.42 (dd, J = 6.8, 1.7 Hz, 1H), 5.23 (s, 2H), 3.56 (td, J = 7.1, 5.7 Hz, 2H), 2.80 (t, J = 7.1 Hz, 2H), 0.06 (s, 1H).

[0055] Compound 25a: 1-(benzyloxy)-6-oxo-N-(pyridin-4-ylmethyl)-1,6-dihydropyridine-2-carboxamide The synthesis method is the same as that of compound 1a, except that a different amine is used, yielding a white solid with a yield of 70%. 1 H NMR (400MHz, DMSO-d 6) δ 9.47 (t, J = 6.1 Hz, 1H), 8.37 – 8.31 (m, 2H), 7.49 (dd, J =9.3, 6.7 Hz, 1H), 7.35 (d, J = 4.2 Hz, 5H), 7.27 – 7.21 (m, 2H), 6.66 (dd, J = 9.3, 1.7 Hz, 1H), 6.40 (dd, J = 6.7, 1.7 Hz, 1H), 5.22 (s, 2H), 4.44 (d, J = 6.0 Hz, 2H).

[0056] Example 3: Synthesis of compound 1b-25b 1. Synthesis of compounds 1b to 5b The corresponding precursor compound (1 eq) was dissolved in methanol, and a 10% sodium hydroxide aqueous solution was added. The mixture was stirred at 40°C, and the reaction was monitored. The reaction was stopped when the starting material was completely eliminated. All methanol was removed from the reaction solution, and the mixture was diluted with water, extracted with dichloromethane, and the aqueous phase was retained. The pH was adjusted to acidic by adding a 10% hydrochloric acid aqueous solution. A white solid precipitated, which was filtered to obtain the product.

[0057] Compound 1b: (benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)glycine White solid, yield 89%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.20 (t, J = 5.9 Hz, 1H),7.51 – 7.42 (m, 3H), 7.37 (dd, J = 5.0, 1.9 Hz, 3H), 6.65 (dd, J = 9.3, 1.7Hz, 1H), 6.29 (dd, J = 6.7, 1.7 Hz, 1H), 5.22 (s, 2H), 3.91 (d, J = 5.9 Hz, 2H).

[0058] Compound 2b: (benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)leucine White solid, yield 87%. 1 H NMR (400 MHz, DMSO-d 6) δ 9.16 (d, J = 8.0 Hz, 1H), 7.47 (dd, J = 9.3, 6.8 Hz, 2H), 7.45 – 7.40 (m, 2H), 7.36 (p, J = 3.8 Hz, 3H), 6.64 (dd, J = 9.3, 1.7 Hz, 1H), 6.23 (dd, J = 6.7, 1.7 Hz, 1H), 5.24 (d, J = 8.4 Hz, 1H), 5.17 (d, J = 8.4 Hz, 1H), 4.37 (ddd, J = 10.0, 7.9, 4.4 Hz,1H), 1.63 – 1.46 (m, 3H), 0.79 (dd, J = 7.8, 6.1 Hz, 6H).

[0059] Compound 3b: (benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)phenylalanine White solid, yield 58%. 1 H NMR (400 MHz, DMSO-d6) δ 9.25 (d, J = 8.2 Hz, 1H), 7.44 (ddd, J = 9.3, 6.7, 2.4 Hz, 1H), 7.34 (p, J = 3.4, 3.0 Hz, 5H), 7.28 (d, J = 5.0 Hz, 5H), 7.23 – 7.16 (m, 5H), 6.62 (ddd, J = 9.3, 5.5, 1.7Hz, 1H), 6.00 (td, J = 6.8, 3.3 Hz, 1H), 5.16 – 5.12 (m, 2H), 4.71 – 4.54 (m,1H), 4.46 (d, J = 3.6 Hz, 2H), 3.13 (td, J = 15.6, 14.8, 5.0 Hz, 1H), 2.93 (dt, J = 13.9, 10.2 Hz, 1H).

[0060] Compound 4b: (1-Benzyloxy-6-oxo-1,6-dihydropyridine-2-formyl)valine White solid, yield 59%. 1H NMR (400 MHz, DMSO- d 6) δ 9.09 (d, J = 8.4 Hz, 1H),7.51 – 7.42 (m, 3H), 7.36 (q, J = 2.9 Hz, 4H), 6.63 (dd, J = 9.2, 1.7 Hz, 1H), 6.22 (dd, J = 6.7, 1.7 Hz, 1H), 5.23 (d, J = 8.4 Hz, 1H), 5.17 (d, J =8.4 Hz, 1H), 4.29 (dd, J = 8.4, 5.8 Hz, 1H), 2.09 (h, J = 6.7 Hz, 1H), 0.85(dd, J = 6.9, 4.9 Hz, 6H).

[0061] Compound 5b: 2-[1-(benzyloxy)-6-oxo-1,6-dihydropyridine-2-formylamino]-3-methylpentanoic acid White solid, yield 64%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.10 (d, J = 8.3 Hz, 1H), 7.44 (ddd, J = 10.7, 7.8, 5.2 Hz, 3H), 7.39 – 7.33 (m, 3H), 6.63 (dd, J =9.3, 1.6 Hz, 1H), 6.22 (dd, J = 6.7, 1.6 Hz, 1H), 5.23 (d, J = 8.4 Hz, 1H), 5.16 (d, J = 8.4 Hz, 1H), 4.32 (dd, J = 8.4, 6.1 Hz, 1H), 1.80 (dtd, J =10.9, 6.6, 4.2 Hz, 1H), 1.39 (dqd, J = 14.7, 7.4, 4.1 Hz, 1H), 1.14 (ddt, J=16.3, 14.5, 7.1 Hz, 1H), 0.83 (d, J = 6.8 Hz, 3H), 0.77 (t, J = 7.4 Hz, 3H).

[0062] 2. Synthetic methods for compounds 1c to 5c and compounds 6b to 25b The corresponding precursor compound (1 eq) was dissolved in a 1:1 mixture of acetate and acid (volume ratio 1:1), stirred at room temperature, and the reaction was monitored by TLC. After 12 h, the reaction was completed, and the acetate-acid mixture was removed under vacuum to obtain a viscous liquid. This liquid was dissolved in ethanol, and an appropriate amount of diethyl ether was added. A white solid precipitated, which was then filtered to obtain the product.

[0063] Compound 1c: (1-hydroxy-6-oxo-1,6-dihydropyridine-2-formyl)glycine White solid, yield 38%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.20 (t, J = 5.9 Hz, 1H),7.51 – 7.42 (m, 3H), 7.37 (dd, J = 5.0, 1.9 Hz, 3H), 6.65 (dd, J = 9.3, 1.7Hz, 1H), 6.29 (dd, J = 6.7, 1.7 Hz, 1H), 5.22 (s, 2H), 3.91 (d, J = 5.9 Hz, 2H).

[0064] Compound 2c: 1-hydroxy-6-oxo-1,6-dihydropyridine-2-formyl)leucine White solid, yield 47%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.14 (d, J = 7.9 Hz, 1H), 7.41 (dd, J = 9.1, 6.9 Hz, 1H), 6.61 (dd, J = 9.0, 1.6 Hz, 1H), 6.30 (dd, J =6.9, 1.6 Hz, 1H), 4.36 (ddd, J= 10.0, 7.8, 4.7 Hz, 1H), 1.79 – 1.50 (m, 3H), 0.89 (dd, J = 9.0, 6.5 Hz, 6H); 13 C NMR (101 MHz, DMSO- d 6) δ 173.85, 160.73, 158.03, 142.20, 137.50, 119.93, 104.94, 51.16, 24.85, 23.40, 21.77.

[0065] Compound 3c: (1-hydroxy-6-oxo-1,6-dihydropyridine-2-formyl)phenylalanine White solid, yield 51%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.38 (d, J = 7.7 Hz, 1H), 7.36 (dd, J = 9.1, 6.9 Hz, 1H), 7.31 – 7.15 (m, 6H), 6.57 (dd, J = 9.1, 1.7Hz, 1H), 6.17 – 6.09 (m, 1H), 4.59 (td, J = 8.7, 5.5 Hz, 1H), 3.74 (s, 2H).

[0066] Compound 4c: (1-hydroxy-6-oxo-1,6-dihydropyridine-2-formyl)valine White solid, yield 63%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.36 (t, J = 7.9 Hz, 1H), 6.59 (d, J = 8.7 Hz, 1H), 6.43 (d, J = 6.8 Hz, 1H), 4.27 (dd, J = 8.3, 5.5Hz, 1H), 2.13 (dt, J = 13.1, 6.5 Hz, 1H), 0.91 (t, J = 6.3 Hz, 6H); 13 C NMR (101 MHz, DMSO-) D6) δ 219.69, 172.82, 160.93, 142.74, 131.10, 120.09, 106.48,58.82, 33.88, 23.43, 17.89.

[0067] Compound 5c: 2-[(1-hydroxy-6-oxo-1,6-dihydropyridin-2-yl)formamido]-3-methylpentanoic acid White solid, yield 58%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.22 (t, J = 8.0 Hz, 1H), 6.97 (d, J = 7.4 Hz, 1H), 6.52 (d, J = 8.4 Hz, 1H), 4.37 (dd, J = 7.9, 5.4Hz, 1H), 1.89 (tt, J = 12.4, 6.0 Hz, 1H), 1.45 (ddd, J = 12.7, 7.7, 4.7 Hz,1H), 1.28 (dq, J = 15.2, 7.4 Hz, 1H), 0.92 (d, J = 6.7 Hz, 3H), 0.84 (t, J =7.3 Hz, 3H).

[0068] Compound 6b: 1-Hydroxy-N-(4-methylbenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 65%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.29 (dd, J = 8.7, 7.1Hz, 1H), 7.19 (d, J = 7.7 Hz, 2H), 7.10 (d, J = 7.8 Hz, 2H), 6.64 (s, 1H), 6.52 (dd, J = 8.8, 1.8 Hz, 1H), 4.41 (d, J = 6.0 Hz, 2H), 2.24 (s, 3H)l; 13 CNMR (101 MHz, DMSO-D 6) δ 201.08, 162.77, 157.86, 151.76, 142.47,138.38,136.54, 136.06, 129.43, 127.74, 121.52, 102.12, 81.22, 53.59, 17.89.

[0069] Compound 7b: N-benzyl-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 48%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.40 – 7.33 (m, 1H), 7.30(d, J = 4.4 Hz, 4H), 7.26 – 7.18 (m, 1H), 6.55 (dd, J = 9.1, 1.7 Hz, 1H), 6.33 (d, J = 6.8 Hz, 1H), 4.41 (d, J = 6.0 Hz, 2H); 13 C NMR (101 MHz, DMSO- D 6)δ 160.97, 157.54, 143.92, 140.44, 137.53, 128.89, 125.87, 118.35, 108.46, 42.90.

[0070] Compound 8b: N-(4-bromobenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 46%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.49 (d, J = 8.1 Hz, 2H),7.32 – 7.18 (m, 3H), 6.71 (s, 1H), 6.52 (dd, J = 8.8, 1.8 Hz, 1H), 4.44 (d, J = 6.0 Hz, 2H).

[0071] Compound 9b: 1-Hydroxy-N-(4-methoxybenzyl)-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 70%. 1H NMR (400 MHz, DMSO- d 6) δ 7.32 – 7.17 (m, 3H), 6.85(d, J = 8.4 Hz, 2H), 6.74 (d, J = 10.4 Hz, 1H), 6.52 (dd, J = 8.7, 1.9 Hz, 1H), 4.40 (d, J = 6.0 Hz, 2H), 3.69 (s, 3H).

[0072] Compound 10b: N-(3,5-dimethoxybenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 66%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.26 (t, J = 6.1 Hz, 1H), 6.55 (dd, J = 9.1, 1.7 Hz, 1H), 6.48 (d, J = 2.3 Hz, 2H), 6.33 (t, J = 2.3Hz, 1H), 6.28 (dd, J = 6.9, 1.7 Hz, 1H), 4.34 (d, J = 6.1 Hz, 2H), 3.69 (s, 6H); 13 C NMR (101 MHz, DMSO- D 6) δ 160.15, 157.30, 142.84, 140.12, 138.70, 124.13, 107.90, 104.22, 100.38, 53.28, 42.87.

[0073] Compound 11b: N-(3,5-dichlorobenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 62%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.36 (t, J = 6.1 Hz, 1H),7.48 (s, 1H), 7.39 (d, J = 12.3 Hz, 3H), 6.56 (d,J = 8.9 Hz, 1H), 6.32 (d, J = 6.8 Hz, 1H), 4.42 (d, J = 5.9 Hz, 2H); 13 C NMR (101 MHz, DMSO- D 6) δ 166.88,158.73, 144.48, 141.87, 136.96, 133.16, 127.62, 126.75, 116.93, 105.61,42.83.

[0074] Compound 12b: N-(4-chlorobenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 58%. ¹H NMR (400 MHz, Chloroform-d) δ 7.42 – 7.12 (m, ¹¹H), 6.62 (dd, J = 9.2, 1.7 Hz, ¹H), 6.52 (dd, J = 6.8, 1.7 Hz, ¹H), 5.20 (s, 2H), 4.46 (d, J = 5.9 Hz, 2H).

[0075] Compound 13b: N-(3,5-difluorobenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 53%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.36 (dd, J = 9.0, 6.9Hz, 1H), 7.14 – 6.89 (m, 3H), 6.56 (dd, J = 9.0, 1.7 Hz, 1H), 6.42 (d, J =6.8 Hz, 1H), 4.45 (d, J = 6.0 Hz, 2H); 13 C NMR (101 MHz, DMSO- D 6) δ 164.23,164.10, 161.78, 161.65, 161.27, 158.61, 144.01, 141.71, 136.75, 120.45,110.73, 110.48, 104.84, 103.11, 102.86, 102.60, 42.59.

[0076] Compound 14b: N-(3-chlorobenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 67%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.34 (t, J = 6.1 Hz, 1H),7.40 – 7.36 (m, 2H), 7.36 – 7.31 (m, 1H), 7.27 (ddt, J = 7.3, 5.6, 1.6 Hz,2H), 6.55 (dd, J = 9.1, 1.7 Hz, 1H), 6.30 (dd, J = 6.9, 1.7 Hz, 1H), 4.41 (d, J = 6.0 Hz, 2H); 13 C NMR (101 MHz, DMSO- D 6) δ 161.05, 158.09, 142.74, 141.69,137.93, 133.56, 130.75, 127.52, 127.42, 126.75, 122.03,105.56, 43.46.

[0077] Compound 15b: N-(4-fluorobenzyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 60%. 1 H NMR (400 MHz, DMSO- d 6) δ 9.30 (t, J = 6.0 Hz, 1H),7.41 – 7.28 (m, 3H), 7.19 – 7.06 (m, 2H), 6.55 (dd, J = 9.1, 1.7 Hz, 1H), 6.29 (dd, J = 6.9, 1.7 Hz, 1H), 4.38 (d, J = 6.0 Hz, 2H); 13 C NMR (101 MHz, DMSO- D6) δ 162.98, 160.92, 160.57, 158.10, 142.77, 137.91, 135.30, 135.27,129.76, 129.68, 120.13, 115.68, 115.47, 104.47, 42.20, 40.57, 40.37, 40.16,39.95, 39.74, 39.53, 39.32.

[0078] Compound 16b: N-(3,5-dichlorophenyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 64%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.71 (d, J = 1.9 Hz, 2H), 7.43 (dd, J = 9.1, 6.9 Hz, 1H), 7.35 (t, J = 1.9 Hz, 1H), 6.62 (dd, J = 9.2, 1.7 Hz, 1H), 6.45 (dd, J = 6.9, 1.6 Hz, 1H); 13 C NMR (101 MHz, DMSO- D 6) δ160.48, 158.60, 142.02, 140.51, 137.89, 134.80, 124.09, 121.04, 118.34,103.74.

[0079] Compound 17b: 1-Hydroxy-N-trimethylyl-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 59%. 1 H NMR (400 MHz, DMSO- d 6) δ 10.10 (s, 1H), 7.46 (dd, J = 9.1, 6.8 Hz, 1H), 6.91 (s, 2H), 6.62 (dd, J = 9.1, 1.7 Hz, 1H), 6.42 (dd, J = 6.9, 1.7 Hz, 1H), 2.24 (s, 3H), 2.18 (s, 6H); 13C NMR (101 MHz, DMSO- D 6) δ159.48, 158.59, 143.27, 138.04, 136.61, 136.00, 131.64, 128.92, 120.09,103.23, 21.93, 15.59.

[0080] Compound 18b: 1-Hydroxy-6-oxo-N-phenyl-1,6-dihydropyridine-2-carboxamide White solid, yield 54%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.98 (d, J = 8.1 Hz, 1H), 7.67 (dd, J = 8.1, 1.4 Hz, 1H), 7.40 (td, J = 8.7, 6.8 Hz, 2H), 7.13 (td, J =7.8, 1.6 Hz, 1H), 6.94 (d, J = 7.2 Hz, 1H), 6.72 (dd, J = 8.8, 1.8 Hz, 1H),3.66 (s, 2H); 13 C NMR (101 MHz, DMSO- D 6) δ 159.30, 136.48, 134.78, 133.29,128.76, 127.56, 125.82, 118.90, 117.07, 108.78, 40.63, 40.42, 40.21, 40.00,39.79, 39.58, 39.37.

[0081] Compound 19b: N-(3,5-dimethoxyphenyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 48%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.41 (dd, J = 9.1, 6.9Hz, 1H), 6.91 (d, J = 2.3 Hz, 2H), 6.61 (dd, J = 9.1, 1.7 Hz, 1H), 6.46 –6.40 (m, 1H), 6.27 (t,J = 2.3 Hz, 1H), 3.70 (s, 6H); 13 C NMR (101 MHz, DMSO- D 6) δ 161.12, 159.19, 158.14, 142.47, 140.46, 137.72, 120.23, 104.34, 98.55,96.67, 55.70, 40.65, 40.44, 40.23, 40.02, 39.81, 39.60, 39.40.

[0082] Compound 20b: N-(3,5-difluorophenyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 60%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.60 – 7.44 (m, 2H), 7.33(t, J = 8.0 Hz, 1H), 7.16 (dd, J = 7.5, 1.8 Hz, 1H), 6.96 (tt, J = 9.4, 2.3Hz, 1H), 6.68 (dd, J = 8.6, 1.8 Hz, 1H).

[0083] Compound 21b: N-(2-bromophenyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 56%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.98 (d, J = 8.1 Hz, 1H), 7.67 (dd, J = 8.1, 1.4 Hz, 1H), 7.40 (td, J = 8.7, 6.8 Hz, 2H), 7.13 (td, J =7.8, 1.6 Hz, 1H), 6.94 (d, J = 7.2 Hz, 1H), 6.72 (dd, J = 8.8, 1.8 Hz, 1H),3.66 (s, 2H); 13 C NMR (101 MHz, DMSO- D6) δ 159.16, 158.08, 142.69, 138.84,137.90, 129.45, 124.79, 120.29, 120.13, 104.26, 40.63, 40.42, 40.21, 40.00,39.79, 39.59, 39.38.

[0084] Compound 22b: N-(2,4-dimethylphenyl)-1-hydroxy-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 65%. 1 H NMR (400 MHz, DMSO- d 6) δ 10.42 (s, 1H), 7.43 (dd, J = 9.1, 6.9 Hz, 1H), 7.34 (d, J = 8.0 Hz, 1H), 7.04 (d, J = 2.0 Hz, 1H), 6.98 (dd, J = 8.1, 2.1 Hz, 1H), 6.64 (dd, J = 9.0, 1.7 Hz, 1H), 6.53 (dd, J =7.0, 1.7 Hz, 1H), 2.23 (s, 3H), 2.19 (s, 3H); 13 C NMR (101 MHz, DMSO- D 6) δ159.32, 158.02, 142.63, 137.49, 135.67, 133.15, 132.56, 131.51, 127.14,125.51, 119.79, 105.48, 40.58, 40.37, 40.16, 39.96, 39.75, 39.54, 39.33,21.04, 18.29.

[0085] Compound 23b: 1-Hydroxy-N-(4-methoxyphenyl)-6-oxo-1,6-dihydropyridine-2-carboxamide White solid, yield 49%. 1 H NMR (400 MHz, DMSO- d 6) δ 10.69 (s, 1H), 7.63 –7.50 (m, 2H), 7.41 (dd, J= 9.1, 6.9 Hz, 1H), 6.94 – 6.83 (m, 2H), 6.58 (dd, J = 9.1, 1.7 Hz, 1H), 6.38 (dd, J = 6.9, 1.7 Hz, 1H), 3.70 (s, 3H). 13 C NMR (101 MHz, DMSO-) D 6) δ 158.70, 158.09, 156.36, 142.97, 138.04, 131.97, 121.66,120.30, 114.51, 104.41, 55.77, 40.55, 40.34, 40.13, 39.92, 39.71, 39.50,39.30.

[0086] Compound 24b: 1-Hydroxy-6-oxo-N-phenethyl-1,6-dihydropyridine-2-carboxamide White solid, yield 47%. 1 H NMR (400 MHz, DMSO- d 6) δ 7.35 (dd, J = 9.1, 6.9Hz, 1H), 7.29 – 7.15 (m, 5H), 6.53 (dd, J = 9.1, 1.7 Hz, 1H), 6.17 (dd, J =6.9, 1.7 Hz, 1H), 3.57 – 3.27 (m, 2H), 2.77 (t, J = 7.3 Hz, 2H). 13 C NMR (101MHz, DMSO- D 6) δ 160.70, 158.04, 142.82, 139.66, 137.83, 129.25, 128.89,126.72, 119.87, 104.41, 41.12, 40.57, 40.36, 40.15, 39.94, 39.74, 39.53,39.32, 35.18.

[0087] Compound 25b: 1-hydroxy-6-oxo-N-(pyridin-4-ylmethyl)-1,6-dihydropyridine-2-carboxamide White solid, yield 74%. 1 H NMR (400 MHz, DMSO- d6) δ 9.67 (t, J = 6.1 Hz, 1H), 8.85 (d, J = 6.2 Hz, 2H), 7.94 (d, J = 5.9 Hz, 2H), 7.41 (dd, J = 9.1, 6.8Hz, 1H), 6.59 (d, J = 8.7 Hz, 1H), 6.48 – 6.34 (m, 1H), 4.69 (s, 2H); 13 C NMR (101 MHz, DMSO-) D 6) δ 161.52, 159.42, 158.13, 142.29, 142.10, 137.92, 125.33,120.75, 104.58, 42.54, 40.66, 40.45, 40.24, 40.04, 39.83, 39.62, 39.41.

[0088] Example 4: Relevant Detection of Compounds 1) Iron ion chelation ability test Experimental methods: A modified CAS detection solution was prepared for detection. The test compounds and positive controls were dissolved in deionized water to obtain final concentrations of 100, 50, 25, 12.5, 6.25, and 3.125 μM. 100 μL of the modified CAS detection solution and 100 μL of the test sample or positive control aqueous solution were added to each well of a 96-well plate. Each sample was tested in triplicate. One column was used as a blank control, with 100 μL of the modified CAS detection solution and 100 μL of deionized water added to each well. After mixing, the 96-well plate was incubated at 37 ℃ for 3 h. The absorbance of each well was measured and recorded using a microplate reader at 620 nm. The EC50 values ​​(μM) of the compounds and positive controls were obtained using Prism software.

[0089] Experimental results: The results of the iron ion chelating ability determination of the compounds are shown in Table 1. The iron ion chelating ability EC of the positive control drug (DFO) is shown in Table 1. 50 The value was 19.99±1.04 μM. All tested compounds had good iron ion chelating ability, and compounds 1c, 2c, 3c, 4c, 5c, 7b, 8b, 10b, 14b, 15b, 16b and 23b had better iron ion chelating ability than DFO.

[0090] 2) Minimum inhibitory concentration (MIC) determination method Experimental methods: Different concentrations of serially diluted antibacterial drug solutions and bacterial suspensions were added to sterilized 96-well polystyrene plates. 100 μL of drug solution was added to wells 1 through 10, with well 1 serving as a growth control and well 12 serving as a blank control (containing only culture medium). The plates were sealed and incubated at 36 °C for 16–20 h to determine the results.

[0091] 3) MTT assay for cytotoxicity Experimental methods: L929 cells were seeded in 96-well plates, with the edge wells filled with sterile PBS. The plates were incubated overnight at 37°C with 5% CO2. Different concentration gradients of the test compound were added to establish a blank control (culture medium only), a negative control (culture medium + cells), and a positive control (cytarabine). The culture medium was removed from each well, and 10 μL of MTT solution (final concentration 0.5 mg / mL) was added to each well. The plates were incubated at 37°C for 4 hours. The supernatant was discarded, and 150 μL of DMSO was added to each well to dissolve the formazan crystals. The plates were shaken for 5 minutes until completely dissolved. The absorbance (OD value) of each well was measured at 570 nm using a microplate reader, with 630 nm used as a reference wavelength to eliminate interference. Cell viability was calculated using the following formula. If the cell viability of the sample group was less than 70% of that of the negative control, it indicated a tendency for cytotoxicity.

[0092] Cell viability (%) = (OD value of negative control group - OD value of blank group) / (OD value of experimental group - OD value of blank group) × 100%.

[0093] Experimental results: Iron ions are a key cofactor for microbial growth and metabolism. Iron chelating agents inhibit the iron uptake pathways of pathogenic microorganisms (such as the hepatotropic system of bacteria) by binding free iron ions in the environment, thereby blocking their proliferation and survival. For example, DFO can significantly reduce the iron-dependent enzyme activity of pathogens and interfere with their energy metabolism by chelating Fe³⁺. As shown in Table 1, the experimental results of this invention demonstrate that DFO has an effect on Propionibacterium acnes (… Propionibacteriumacnes-P.acnes PA has certain antibacterial activity (MIC > 128 μg / mL), but it is not effective against the other three bacteria (Staphylococcus aureus). Staphylococcus aureus-S.aureus Methicillin-resistant Staphylococcus aureus Methicillin-resistant Staphylococcus aureus and E. coli Escherichia coli - E. coli None of them showed inhibitory activity. The compounds described in this invention exhibited varying degrees of antibacterial activity against three types of bacteria, inhibiting more than two types, with better inhibitory effects against Gram-positive bacteria (Table 1).

[0094] The cytotoxicity assay results are shown in Table 1. The cytotoxicity IC50 values ​​of DFO, c-series compounds, and b-series compounds are shown in Table 1. 50 The values ​​were all >50 μM, and no obvious cytotoxic activity was detected at the in vitro cell level.

[0095] Table 1 Results of bioactivity assays of the compounds

[0096] Note: PA, Propionibacterium acnes-P. acnes Propionibacterium acnes; SA Staphylococcus aureus - S. aureus Staphylococcus aureus; MRSA Methicillin-resistant Staphylococcus aureus Methicillin-resistant Staphylococcus aureus; EC, Escherichia coli - E. coli , Escherichia coli; —, indicating no antibacterial activity was detected.

[0097] 4) Test of anti-inflammatory activity of LPS-stimulated RAW264.7 macrophages Experimental methods: RAW264.7 cells were seeded in 96-well plates and incubated overnight at 37°C in a 5% CO2 incubator. LPS (1 μg / mL) and test compounds of different concentration gradients were added and incubated in a CO2 incubator for 24 h. Griess Reagent I and Griess Reagent II (50 µL each) were added to each well in sequence, and the absorbance was measured at 540 nm. The concentration of nitric oxide in the sample was calculated based on the standard curve.

[0098] Experimental results: Given that iron plays a role in the immune response, and that excessively high iron levels can exacerbate the inflammatory process, iron chelates possess anti-inflammatory effects. For example... Figure 2 As shown, the positive control drug DFO had almost no effect on NO production in RAW 264.7 macrophages upon exposure to lipopolysaccharide (LPS), indicating that DFO lacks anti-inflammatory activity. Among the compounds provided in this invention, the b-series compounds all reduced NO production in RAW 264.7 macrophages upon LPS exposure. Specifically, compounds 11b, 12b, 13b, 14b, 15b, 16b, 17b, 18b, 20b, 23b, and 24b showed significantly higher anti-inflammatory effects than DFO (P < 0.05). These results demonstrate that the compounds described in this invention possess superior anti-inflammatory activity compared to DFO.

[0099] 5) Western blot method for detecting HIF-α expression Experimental methods: Hep3B cells were seeded in 6 cm dishes and incubated overnight at 37°C in a 5% CO2 incubator. A compound was added to a final concentration of 20 μM, and the cells were incubated in a CO2 incubator for 1, 3, 6, and 12 h. Cells were harvested in RIPA buffer. Protein lysates were separated by SDS-PAGE and transferred to nitrocellulose membranes (GE Healthcare). The membranes were incubated with primary antibody and then with horseradish peroxidase-labeled secondary antibody. Immune complexes were detected using an Immobilon™ Western chemiluminescence HRP substrate (Millipore) imager and captured on a Tanon 5200 imaging system.

[0100] Experimental results: Iron ion chelating agents inhibit PHD activity and block the degradation pathway of HIF-α by chelating free iron ions. The stability of this series of derivatives for HIF-α was determined using Western blotting (WB). Figure 3 Under normoxic conditions, HIF-1α protein was not detected in human hepatocellular carcinoma Hep3B cells. However, after treatment with 20 μM concentrations of 11b, 17b, 8b, 22b, 23b, 14b, and 18b for 24 h, significant expression of HIF-1α and HIF-2α proteins was observed, while downstream GLUT1 expression was also promoted. This indicates that compounds 11b, 17b, 8b, 22b, 23b, 14b, and 18b can stabilize HIF-α protein. These results confirm that the series of iron ion chelating agents provided in this invention possess HIF-α stabilizing activity.

[0101] 6) Cell scratch assay Experimental methods: L929 cells were seeded in 24-well plates and incubated overnight at 37°C with 5% CO2. Using a 200 μL sterile pipette tip, scratches were made perpendicular to the marking lines on the back of the plate, ensuring the tip was vertical and the pressure was even to guarantee consistent scratch width. The plates were gently rinsed three times with sterile PBS to remove detached cell debris. The medium was then replaced with low-serum medium (FBS=2%) to minimize interference from cell proliferation on migration results. The test compound was added to a final concentration of 10 μM, and the plates were incubated in a CO2 incubator for 48 h. The plates were then removed and photographed under a microscope. The scratch area was measured using ImageJ software, and the migration rate was calculated using the following formula: Migration rate (%) = (0h scratch area - 48h scratch area) / 0h scratch area × 100% Experimental results: Table 2 Results of L929 cell scratch area and migration rate

[0102] Iron chelators play a dual role in wound healing by regulating iron homeostasis and inhibiting oxidative stress and microbial infection. Studies have found that HIF-1 promotes epidermal and angiogenesis and promotes laminin expression. The compounds described in this invention have extremely strong iron chelating efficacy and can stabilize HIF-α. Therefore, this invention selected representative compounds and evaluated their effects on promoting fibroblast migration. Mouse fibroblast L929 cells cultured in vitro were scratched, and the test compound (10 μM) was added. After incubation for 72 h, the scratch area was analyzed using ImgeJ, and cell migration rate was calculated. The results are as follows: Figure 4 As shown in Table 2, the migration rate of L929 cells treated with the test compounds was increased (Table 2), and the number of newly generated cells in the scratched area was significantly increased.

[0103] 7) Preparation and characterization of 17b nanomicelles (17b-OSA@DSPE) Experimental methods: 22b was modified in dichloromethane using esterification with 2-octenyl succinic anhydride (OSA, FDA approved for food grade) (utilizing the reactivity of the hydroxyl group), and then further prepared by co-assembling with PEGylated modified material (DSPE-PEG2000-NHS) to obtain self-assembling nanomicelles (22b-OSA@DSPE).

[0104] Compound 22b and OSA were dissolved in anhydrous dichloromethane (CH₂Cl₂). EDC and DMAP were then added dropwise, and the reaction mixture was reacted overnight at 45 °C. After the reaction was nearly complete, the reaction mixture was cooled and washed successively with 5% citric acid, saturated sodium bicarbonate, and saturated brine to purify the intermediate coupling compound. The purification results were analyzed... 1 H nuclear magnetic resonance (NMR) characterization.

[0105] Nanomicelles (22b-OSA@DSPE) were prepared using a solvent evaporation-ultrasound method. The 22b-OSA prodrug and DSPE-PEG2k were dissolved in 20% acetone and then self-assembled into nanoparticles in deionized water under ultrasonication. The acetone was subsequently removed slowly by rotary evaporation. The morphology of 22b-OSA@DSPE was then visualized using transmission electron microscopy (TEM).

[0106] Experimental results: like Figure 5 As shown in Figure A, 22b-OSA@DSPE nanomicelles dispersed in water form an emulsion. Figure 5 As shown in B, 22b and 22b-OSA were dissolved in a deuterated chloroform (CDCl3) solution. 1¹H-NMR results confirmed that the characteristic peaks of hydrogen (a, b) on the double bond at OSA in 22b-OSA were located between 5 and 6 ppm, while the characteristic peak of hydrogen (c) on the methylene group connected to R-COO-N was located at approximately 2 ppm, proving that the 22b compound and the OSA compound were successfully synthesized via esterification. TEM images showed that the 22b-OSA@DSPE nanomicelles were spherical with a particle size of approximately 20-30 nm. Figure 5 C). The inflammatory microenvironment of diabetes is pH 4-6. Based on the degradation characteristics of ester bonds under acidic conditions, high-performance liquid chromatography (HPLC) was used to simulate the release rate of 22b-OSA@DSPE nanomicelles at pH 5.5, which was approximately 10.2% after 24 hours. Figure 5 D).

[0107] 8) Intracellular ROS release assay Experimental methods: A hyperglycemic environment is a recognized factor contributing to poor wound healing in diabetic patients. Elevated blood glucose levels can lead to iron overload; excessive iron catalyzes the formation of reactive oxygen species (ROS), accelerating aging and stimulating oxidative damage, thereby inducing complications of chronic hyperglycemia.

[0108] L929 cells were treated with high glucose (33.3 mM glucose) for 5 days to induce oxidative damage. Simultaneously, the test compound was added, and changes in ROS in the cells were detected by chemiluminescence. In short, a dichlorodihydrofluorescein diacetate (DCFH-DA) probe solution (Beyotime, Shanghai, China) was diluted to 10 μM staining solution and added to the cells. Cells were incubated and washed, and intracellular ROS oxidized non-fluorescent DCFH to generate fluorescent DCF. Flow cytometry (Cytek® Guava® easyCyte™ HT) was used to detect the fluorescence intensity of the probe-loaded cell samples to characterize intracellular ROS levels.

[0109] Experimental results: Figure 6Results from A and 6B showed that the proportion of ROS-positive cells in the low-glucose L929 group was 21.8%, while that in the high-glucose L929 group was 60.1%, with significantly increased fluorescence density (P < 0.001). This indicates a significant increase in intracellular ROS production, successfully establishing a high-glucose-induced oxidative damage model in L929 cells. Compared to the model group (high-glucose L929 group), the 17b-12.5 μM group significantly reduced the proportion of ROS-positive cells (23.6%) and fluorescence density (P < 0.001), exhibiting superior antioxidant activity compared to the positive control drug DFO group (35.9%). Furthermore, compounds 23b, 14b, and 15b also demonstrated good ROS inhibitory activity, with ROS-positive cell proportions of 35.3%, 44.6%, and 48.6%, respectively, and significantly reduced fluorescence density. Figure 6 C and 6D showed that 22b-OSA@DSPE nanomicelles could significantly inhibit ROS generation in the high glucose-induced L929 cell line, with effects comparable to DFO.

[0110] 9) Experiment on the promotion of healing of diabetic refractory wounds by 17b nanomicelles (17b-OSA@DSPE) Experimental methods: To investigate the in vivo efficacy of 17b nanomicelles on diabetic wound healing, a diabetic rat model with full-thickness skin wounds induced by streptozotocin (STZ) was established. Blood glucose levels in Sprague-Dawley (SD) rats in the PBS and STZ groups were monitored; a fasting 8-hour blood glucose level >16.7 mmol / L indicated successful induction of diabetes. After anesthesia, four 10 mm diameter full-thickness skin wounds were created on the back of the diabetic rats via a punch, evenly distributed along both sides of the spine, and the rats were randomly divided into four groups. Except for the NC control group, the skin wounds of the other three groups (Model group, DFO group, and 17b group) were treated with 10 μL of Pseudomonas aeruginosa (PAO1 type, 108 CFU / mL) to establish diabetic refractory wounds. The NC control group and Model group were treated with 50 μL of control solvent daily, while the treatment groups were treated with DFO (1 mM, 50 μL) and 17b (50 mM, 50 μL), respectively, daily.

[0111] Experimental results: Experimental results are as follows Figure 7 As shown in A and 7B, compared with the NC group, the Model group, after Pseudomonas aeruginosa infection, experienced slower wound healing, with the suppuration period lasting up to 5 days and scab formation beginning on day 6. Compared with the Model group, both the DFO and 17b groups accelerated wound healing, with scab formation beginning on days 3 and 2, respectively, while also reducing wound area. The rate of wound area reduction in the 17b group throughout the healing process was comparable to that in the DFO group, highlighting its potential as an effective strategy for diabetic wound management.

[0112] In summary, the compounds isolated by this invention can be used as novel iron ion chelating agents in stabilizing HIF expression and in anti-inflammatory, antibacterial, and diabetic wound healing drugs.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A class of pyrrolidone derivatives, characterized in that, Its structural formula is shown in equation (Ⅰ): ， Equation (Ⅰ), Wherein R1 is selected from at least one of the following substituents: 。 2. The pyrrolidone derivative according to claim 1, characterized in that, The pyrrolidone derivatives specifically include the following compounds: 。 3. The method for preparing the pyrrolidone derivative according to claim 2, characterized in that, The preparation methods for carboxylic acid compounds, i.e., compounds 1c-5c, include the following steps: Starting with 6-bromo-2-pyridinecarboxylic acid, 6-bromo-2-pyridinecarboxylic acid was oxidized with oxytrifluoroacetic acid to obtain compound S2, which was then hydrolyzed in an aqueous potassium hydroxide solution to give 6-hydroxypyridine-2-carboxylic acid, namely S3. The nitrogen hydroxyl group was further protected with benzyl bromide to obtain benzyl-protected hydroxypyrrolidone, namely compound S4. The benzyl-protected compound S4 was reacted with glycine derivatives with different substitutions and β-alanine to obtain compounds 1a-5a. Then, the benzyl groups protecting the carboxyl and hydroxyl groups were removed by alkaline hydrolysis and acid hydrolysis, respectively, to obtain carboxylic acid compounds 1c-5c; 。 4. The method for preparing the pyrrolidone derivative according to claim 2, characterized in that, The synthetic route of aryl compounds 6b-25b is shown below. The benzyl-protected hydroxypyrrolidone acid, compound S4, is reacted with an aryl amine derivative. First, the intermediate 6a-25a series of compounds are obtained by condensation reaction. Then, the benzyl group is removed by hydrolysis to obtain the final product 6b-25b. 。 5. The use of the pyrrolidone derivative according to claim 1 or 2 in the preparation of anti-inflammatory drugs.

6. The use of the pyrrolidone derivative according to claim 1 or 2 in the preparation of antibacterial drugs.

7. Use of the pyrrolidone derivative of claim 1 or 2 in the preparation of a medicament for treating diseases related to wound healing.

8. The application according to claim 7, characterized in that: The diseases associated with wound healing include wounds caused by hyperglycemia, wounds caused by atherosclerosis and anemia, oral mucosal diseases, inflammatory wounds caused by bacterial infections, chronic wounds caused by foreign body residue, rheumatoid arthritis, systemic lupus erythematosus, pressure sores, burns, frostbite, surgical incisions with infection, and wounds caused by malignant tumors.

9. The use of the pyrrolidone derivative according to claim 1 or 2 in the preparation of an iron ion chelating agent to improve iron overload disease.

10. The use of the pyrrolidone derivative according to claim 1 or 2 in the preparation of HIF-α stabilizers.

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