D-a-d type near-infrared organic molecules, preparation method and application thereof

Abstract

The application provides a D-A-D type near-infrared organic molecule and a preparation method and application thereof. The compound has a near-infrared emission characteristic suitable for chronic wound diagnosis and treatment, can effectively penetrate the shallow to middle layer tissue of the wound, and significantly reduces self-absorption interference by reasonable Stokes shift; the PDT-PTT performance is excellent, and meets the application requirement of wound treatment. The excellent light diagnosis and treatment activity further guarantees the stability of the diagnosis and treatment signal and the energy transfer efficiency.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, specifically relating to a class of DAD-type near-infrared organic molecules and their preparation methods and applications. Background Technology

[0002] Diabetes has become one of the most prevalent chronic metabolic diseases worldwide, affecting over 460 million people globally. Approximately 15% of these patients may develop chronic wound problems such as diabetic foot ulcers (DFU) during the course of their disease. Related studies indicate that the long-term management and care costs of DFU account for approximately 20%–40% of total diabetes healthcare expenditures, placing a heavy burden on healthcare systems and significantly impacting patients' quality of life.

[0003] In the hyperglycemic microenvironment, impaired local leukocyte function and decreased angiogenesis make DFU (dampness-induced fibrosis) chronic wound areas highly susceptible to bacterial colonization and infection, with an infection rate exceeding 70%, accompanied by a high risk of tissue necrosis and functional loss, ultimately leading to amputation rates as high as 30%. In actual nursing care, antibiotics remain an important means of controlling infection; however, their long-term or inappropriate use has led to the widespread emergence of methicillin-resistant Staphylococcus aureus and other drug-resistant strains, significantly weakening the effectiveness of traditional antibacterial strategies. Simultaneously, existing conventional wound dressings are mainly used to maintain a moist environment, lacking both highly effective antibacterial capabilities and failing to adapt to the pathological microenvironment of DFU wounds characterized by hypoxia and oxidative stress imbalance, making it difficult to achieve precise diagnosis and treatment and synergistic antibacterial action to fundamentally improve the microenvironment of chronic wounds.

[0004] In recent years, photoresponsive antibacterial and wound care technologies have attracted widespread attention due to their non-invasive nature and low risk of drug resistance. Photothermal therapy (PTT) can disrupt bacterial structures through photothermal conversion, while photodynamic therapy (PDT) relies on reactive oxygen species (ROS) to cause oxidative damage to bacterial nucleic acids and proteins. However, the core supporting materials for these technologies still face several technical bottlenecks: inorganic nanomaterials (such as gold nanorods and graphene) have high photothermal conversion efficiency, but their biodegradability is poor, leading to long-term accumulation in vivo and potential safety hazards; traditional organic small-molecule photoresponsive materials, such as indocyanine green (ICG), while exhibiting good biocompatibility, suffer from insufficient photostability, with their activity decreasing by more than 50% after 30 minutes of continuous light exposure, and their molecular structure tunability is limited, making it difficult to achieve multifunctional synergistic integration. Furthermore, the photothermal conversion efficiency of existing organic photothermal materials is mostly concentrated between 20% and 30%, and the bactericidal rate of single photodynamic materials is generally only 80% to 90%, which is insufficient to meet the needs of efficient antibacterial treatment and rapid repair of chronic wounds. Currently, the core supporting materials for this type of technology still face technical bottlenecks such as separation of diagnosis and treatment, single function, and poor performance adaptability.

[0005] From a molecular design perspective, the DAD structural units commonly found in existing organic photoresponsive molecules are mostly constructed based on traditional frameworks such as porphyrins, which have limited structural modification space and typically have molar absorptivity below 2.0 × 10⁻⁶. 4 L·mol -1 ·cm -1 This results in insufficient capture efficiency of the excitation light. Simultaneously, the strong exciton effect in the system easily inhibits the effective transfer of excited-state energy to reactive oxygen species (ROS) generation channels, thereby reducing ROS yield and limiting its antibacterial properties. Furthermore, existing research largely focuses on single photoresponse functions, neglecting the integrated needs of near-infrared imaging guidance, PTT-PDT synergistic antibacterial action, and active repair promotion urgently required for chronic wound treatment, making it difficult to meet the clinical requirements of precision medicine.

[0006] It is worth noting that BF has been extensively studied in the field of organic light-emitting diodes (OLEDs) in recent years. 2 Curcumin derivative materials offer new molecular design insights for overcoming the aforementioned technological bottlenecks. These materials possess excellent optical properties such as high luminescence intensity, high brightness, and tunable fluorescence wavelength. Existing research indicates that their intramolecular electron transfer characteristics facilitate the induction of ROS generation under illumination, demonstrating potential photodynamic antibacterial capabilities. Furthermore, the photoquenching phenomenon exhibited by these materials in aqueous solutions suggests that their excited-state energy can be effectively converted into heat energy through non-radiative transitions, providing a physical basis for the realization of photothermal effects. However, research on the application of these materials in the biomedical field is still in its early stages. Their optical properties do not match the needs of biological diagnosis and treatment: absorption and emission wavelengths are not precisely tuned to the near-infrared region, resulting in insufficient tissue penetration; and the photoresponse mechanism is singular, failing to simultaneously achieve efficient PTT and PDT synergistic effects, thus not yet directly meeting the precise diagnostic and treatment needs of DFU chronic wounds. However, the application research of this type of material in the biomedical field is still in its early stages. Its optical properties do not match the needs of biological diagnosis and treatment: the absorption and emission wavelengths are not tuned to the near-infrared region I, and the tissue penetration ability is insufficient; moreover, the photoresponse mechanism is simple, which makes it difficult to achieve effective and stable PDT-PTT synergistic treatment at the wound site. It cannot yet meet the needs of precise diagnosis and treatment of DFU chronic wounds.

[0007] Therefore, there is an urgent need to optimize these organic materials through molecular structure innovation and functional regulation, developing novel organic molecular materials that combine near-infrared imaging capabilities, highly efficient PTT-PDT synergistic antibacterial properties, excellent photostability, and biocompatibility. This would address the problems of existing materials, such as separation of diagnosis and treatment, limited functionality, and poor photostability, enhancing their application potential in the antibacterial control and repair promotion of chronic wounds, and providing a new solution for the treatment of refractory chronic wounds such as diabetic foot ulcers. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention constructs a class of DAD-type near-infrared organic molecules with imaging and antibacterial functions under light irradiation by regulating the electron donor (D), thiophene bridging unit, and boron heterocyclic acceptor (A). These molecules have the structure shown in the following general formula (I):

[0009]

[0010] (I)

[0011] Wherein: R1 and R2 are the same or different, are independently selected from those without substitution, and are arbitrarily selected by one, two or more R... a The following groups are substituted: C 1-15 Alkyl, oxaC 3-12 Alkyl, C 6-20 Aryl, two C 6-20 Aryl groups are either spirocyclic groups or tetraphenylethylene groups formed by sharing a single carbon atom;

[0012] R a Selected from the following groups: halogen, C 1-15 Alkyl, C 1-12 Alkoxy, C 6-20 Aryl or 5-22 heteroaryl groups;

[0013] Alternatively, R1 and R2, together with their connected N, form a ring, constituting a non-substitutable structure, which can be arbitrarily replaced by one, two, or more Rs. b Substituted groups include: 5-22 membered heteroaryl groups, or E is selected from O, S, or Se; R3 and R4 may be the same or different, and are independently selected from H and C. 1-12 Alkyl or C 1-12 Alkoxy;

[0014] R b Selected from the following groups: halogen, C 1-12 Alkyl, C 1-12 Alkoxy, C 6-20 Aryl or 5-22 heteroaryl compounds.

[0015] According to embodiments of the present invention, R1 and R2 may be the same or different, and are independently selected from those without substitution, optionally by one, two or more R1 and R2. a The following groups are substituted: C 1-12 Alkyl, oxaC 3-6 Alkyl, C 6-14 Aryl, two C 6-14 Aryl groups are spirocyclic groups or tetraphenylethylene groups formed by sharing a single carbon atom;

[0016] R a Selected from the following groups: halogen, C 1-6Alkyl, C 1-6 Alkoxy, C 6-14 Aryl, 5-14 heteroaryl.

[0017] According to an embodiment of the invention, R1 and R2, together with their associated N, form a ring, constituting a non-substitutable structure, optionally occupied by one, two, or more Rs. b Substituted 5-14 heteroaryl groups or Where E is selected from O, S, or Se; R3 and R4 may be the same or different, and are independently selected from H or C. 1-6 Alkyl or C 1-6 Alkoxy;

[0018] R b Selected from the following groups: halogen, C 1-6 Alkyl, C 1-6 Alkoxy, C 6-14 Aryl, 5-14 heteroaryl.

[0019] According to an embodiment of the present invention, R1 and R2 may be the same or different, and are independently selected from C. 1-6 Alkyl, oxaC 3-6 alkyl, , , , , , ;

[0020] R a Selected from C 1-6 Alkyl, C 6-14 Aryl or 5-14 heteroaryl; n is 0, 1, 2, 3 or 4;

[0021] For example, R a It is selected from methyl, ethyl, isopropyl, tert-butyl or phenyl.

[0022] According to an embodiment of the invention, R1 and R2, together with their connected N, form a ring, constituting a non-substitutable structure, optionally dominated by a C. 1-6 Alkyl-substituted N-carbazole, or E is selected from O, S, or Se; R3 and R4 may be the same or different, and are independently selected from H and C. 1-6 Alkyl or C 1-6 Alkyl group.

[0023] According to some specific embodiments of the present invention, R1 and R2 together with the N connected to them form a ring, constituting a non-substitutable structure, optionally dominated by a C. 1-4 Alkyl-substituted N-carbazole, or E is selected from O, S, or Se; R3 and R4 may be the same or different, and are independently selected from H and C. 1-4 Alkyl or C 1-4 Alkyl group.

[0024] In some embodiments of the present invention, R1 and R2 may be the same or different, and are independently selected from the following groups:

[0025] .

[0026] According to an embodiment of the present invention, R1, R2 and their associated N form a ring, together constituting the following functional group: , , , , , .

[0027] In some specific embodiments of the present invention, the structure represented by formula (I) is selected from one of the following structures:

[0028]

[0029] .

[0030] The definitions of each core unit in the structure shown in formula (I) of this invention are determined based on biomedical adaptability:

[0031] 1) In formula (I) It is the core functional unit of the organic photodynamic-photothermal antibacterial material of this invention. It has a certain electron-donating ability, its highest occupied molecular orbital (HOMO) energy level is -5.0~-6.5 eV, and it is conjugated with thiophene and boron heterocyclic acceptor units, which can ensure efficient charge transfer and near-infrared luminescence performance within the entire molecule.

[0032] 2) The thiophene unit in formula (I) is the key bridging unit connecting the electron donor and acceptor in the molecule of the organic photodynamic-photothermal antibacterial material of this invention. It connects with the thiophene unit at positions 2 and 5 via carbon atoms respectively. It is connected to and conjugated with boron heterocyclic acceptors.

[0033] 3) In formula (I), the boron heterocyclic acceptor unit is 2,2-difluoro-5-ethoxycarbonyl-2H-1,3,2-dioxoboron heterocycle. The ethoxycarbonyl group enhances the electron-withdrawing ability of the acceptor, adapts to the D unit to achieve efficient charge transfer to ensure near-infrared luminescence in the first region; the difluoro-substituted structure can improve the stability of the ring, avoid degradation of the compound in wound environments, and optimize the solubility of the molecule.

[0034] The compounds of this invention possess near-infrared emission characteristics suitable for chronic wound treatment, effectively penetrating from the superficial to the middle layers of wound tissue. A well-defined Stokes shift significantly reduces self-absorption interference. Their excellent photothermal-to-photothermal (PDT-PTT) performance meets the requirements of wound treatment applications. Their superior photothermal activity further ensures the stability of the therapeutic signal and energy transfer efficiency.

[0035] The present invention also provides a method for preparing DAD-type near-infrared organic molecules as described above, comprising the following steps:

[0036]

[0037] Wherein, R1 and R2 have the definitions described above;

[0038] Compound M3 reacts with ethyl acetoacetate and boron trifluoride diethyl ether to give the structure shown in formula (I).

[0039] According to an embodiment of the present invention, the DAD-type near-infrared organic molecule is prepared by "coupling-aldehyde-condensation cyclization", and its synthetic route is as follows:

[0040]

[0041] Step 1 (Coupling): The molar ratio of the raw materials is aromatic amine precursor compound M1: 2-bromothiophene: sodium tert-butoxide = 1:(2.0-3.0):(3.0-5.0); the reaction conditions are Pd2(dba)3 as the palladium source, P... t The catalytic system with Bu3 as the ligand was refluxed at 110-120 °C for 2-12 h under nitrogen protection using anhydrous toluene as the solvent; the aromatic amine-thiophene intermediate M2 was obtained by column chromatography purification.

[0042] Step 2 (aldehyde hydration): The molar ratio of the raw materials is intermediate M2:POCl3 = 1:(1.0-1.5); anhydrous DMF is used as solvent, and the reaction conditions are 0 ℃, nitrogen protection, POCl3 is added dropwise, the reaction is kept at this temperature for 2-12 h, then the temperature is raised to room temperature for 0.5-12 h, the reaction solution is poured into saturated Na2CO3 aqueous solution to precipitate, ethyl acetate is extracted, and column chromatography is used to purify intermediate M3;

[0043] Step 3 (condensation cyclization): The molar ratio of the raw materials is intermediate M3: ethyl acetoacetate: boron source = (2.0-2.5): 1: (1.0-1.5), and the molar amount of n-butylamine is 50%-70% of that of ethyl acetoacetate; the reaction conditions are as follows: first, boron complexation is carried out at 50-60 °C for 10-60 min, then n-butylamine is added in two portions and reacted overnight, followed by column chromatography and multiple precipitation purifications to obtain the target product.

[0044] The present invention also provides a pharmaceutical composition comprising the DAD-type near-infrared organic molecule as described above.

[0045] According to an embodiment of the present invention, the pharmaceutical composition is a bactericide.

[0046] According to an embodiment of the present invention, the pharmaceutical composition is a photodynamic-photothermal bactericide.

[0047] According to an embodiment of the present invention, the pharmaceutical composition is at 0.5 W / cm 2 Irradiation with a 660 nm laser for more than 1 minute, such as 1~60 minutes or 5~15 minutes, can act as a photodynamic-photothermal bactericide.

[0048] According to an embodiment of the present invention, the photodynamic-photothermal bactericide is used to kill the following bacteria: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus epidermidis, etc.

[0049] This invention provides the use of the DAD-type near-infrared organic molecules described above in the preparation of medicaments for treating chronic wound healing.

[0050] According to an embodiment of the present invention, the chronic wound is a chronic wound caused by diabetic foot ulcer.

[0051] The present invention provides the use of the DAD-type near-infrared organic molecules described above in the preparation of bactericides (e.g., photodynamic bactericides).

[0052] The technical solution of the present invention has the following advantages over the prior art:

[0053] (I) Structural Innovation Enables Therapeutic Synergy: The skeletal design of the compounds in this invention endows these DAD-type organoboron heterocyclic materials with multifunctional integrated universality of "near-infrared imaging-PTT-PDT". For example, compound C-16 has an absorption wavelength of 692 nm and a fluorescence emission wavelength of 845 nm, achieving a photothermal conversion efficiency of 40% for PTT therapy. It can generate various ROS for PTT therapy through type I / II PTT, including singlet oxygen (…). 1 O2), superoxide anion (·O2) -It generates hydroxyl radicals (·OH), adapting to various oxygen-rich / hypoxic environments for different wounds. In contrast, conventional DAD-type organoboron heterocyclic materials generally only generate one type of ROS and have poor photothermal stability, significantly decreasing after three cycles. The rich functionality of the material in this application enables controllable PDT-PTT synergistic therapy and can also improve treatment efficiency and efficacy through near-infrared 1-zone fluorescence imaging guidance. Compared to the 20%-30% conventional photothermal conversion efficiency of existing boron heterocyclic DAD-type organic photothermal materials and the 80%-90% sterilization rate of single phototherapy materials, the overall performance of the material in this invention represents a significant leap, solving the core pain point of insufficient efficiency in traditional materials. Compared to existing single-function photoresponsive materials, the overall performance represents a qualitative leap.

[0054] (ii) Excellent performance and safety: The aqueous solution of the compound of this invention has stable photothermal performance after 5 cycles of light switch, with an activity decrease of <5%, and can stably generate a variety of ROS within the pH range of 4.5-9.0; the zeta potential ensures that it stays in the wound for more than 6 hours; it is an organic small molecule, which is easily metabolized and has no obvious biological toxicity. The hemolysis rate of its 200 μM concentration aqueous solution is <5%, and it has high biocompatibility and meets medical standards.

[0055] (III) Controllable cost and high conversion value: The raw materials of the compound of this invention are commercially available conventional reagents. The total yield of the three-step synthesis is about 35%, and the cost is reduced by 60% compared with precious metal materials. In in vitro experiments, the sterilization rate is >99%. In animal experiments, DFU improves the healing efficiency by 5 times, significantly reduces the risk of amputation, and has a clear clinical prospect.

[0056] Terminology Definitions and Explanations

[0057] Unless otherwise stated, the definitions of groups and terms recorded in this application specification and claims, including definitions as examples, exemplary definitions, preferred definitions, etc., can be arbitrarily combined and combined with each other, and the combined group definitions and compound structures are all within the protection scope of this application.

[0058] In this application, some groups marked with an asterisk (*) indicate connection sites.

[0059] "More than three" means three or more; "optionally substituted" means that it can be substituted or not substituted; "substitution" means that one or more hydrogen atoms in the group are replaced by the corresponding substituent, and the substitution site does not affect the core structure and function of the group.

[0060] Term "C" 1-15 "Alkyl" refers to a straight-chain or branched saturated monovalent hydrocarbon group having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 carbon atoms, preferably "C". 1-12 Alkyl or C 1-6Alkyl group. The "C" 1-12 "Alkyl" refers to a straight-chain or branched saturated monovalent hydrocarbon group having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms. The term "C"... 1-15 Alkyl", C 1-12 Alkyl or C 1-6 Alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-hexyl, etc.; C is particularly preferred. 1-3 Alkyl (methyl, ethyl, n-propyl or isopropyl).

[0061] The term "oxo-C" 3-12 "alkyl" refers to "C 3-12 An alkyl group formed by replacing 1, 2, 3, 4, 5, or 6 carbons with oxygen, wherein the "C" is an alkyl group. 3-12 "Alkyl" refers to a straight-chain or branched saturated monovalent hydrocarbon group having 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms, preferably "oxa-C". 3-6 alkyl".

[0062] Term "C" 6-20 "Aryl" refers to a monovalent aromatic or partially aromatic monocyclic, bicyclic, or tricyclic hydrocarbon ring having 6 to 20 carbon atoms, preferably "C". 6-14 "Aryl", such as phenyl, naphthyl, fluorenyl, anthraceneyl, tetraphenylethylene, etc.; where "C" 6-20 "Aryl group forming a spirocycle by sharing a single carbon atom" refers to two or more carbon atoms. 6-20 Aryl groups form spirocyclic structures linked by single carbon atoms.

[0063] The term "5-22-membered heteroaryl" refers to a monovalent monocyclic, bicyclic, or tricyclic aromatic ring system having 5 to 22 ring atoms (including 1 to 5 heteroatoms independently selected from O, S, or ), preferably "5-14-membered heteroaryl".

[0064] The term "halogen" refers to fluorine, chlorine, bromine, and iodine atoms. Attached Figure Description

[0065] Figure 1 The images show (A) zeta potential diagram and (B) DLS particle size distribution of compound C-16.

[0066] Figure 2 The following are the (A) UV-Vis absorption spectrum, (B) normalized fluorescence emission spectrum, and (C) fluorescence spectrum of compound C-16.

[0067] Figure 3 Compound C-16 and control group (A) were prepared using 2,2,6,6-tetramethylpiperidine (TEMP) as... 1(A) Electron spin resonance (ESR) spectrum of O2 scavenger; (B) O2 scavenger with 5,5-dimethyl-1-pyrrolline-N-oxide (DMPO) as the scavenger. - (C) ESR spectrum of the ·OH scavenger; ESR spectrum of DMPO as the ·OH scavenger (sample concentration 1.5 mg / mL, irradiation conditions 0.5 W / cm²). 2 Irradiation with a 660 nm laser for 10 min).

[0068] Figure 4 The following are the photodynamic oxidation performance test results of compound C-16 under different oxygen sources. (A) Absorption spectrum (time gradient) of the TMB oxidation product oxTMB in the presence of 50 μM compound C-16 with O2 as the oxygen source, for different irradiation times; (B) Kinetic curve (concentration gradient) of the absorbance of the TMB oxidation product oxTMB at 450 nm as a function of time in the presence of different concentrations of compound C-16 with O2 as the oxygen source; (C) Absorption spectrum (time gradient) of the TMB oxidation product oxTMB in the presence of 50 μM compound C-16 with H2O2 as the oxygen source, for different irradiation times; (D) Kinetic curve (concentration gradient) of the absorbance of the TMB oxidation product oxTMB at 450 nm as a function of time in the presence of different concentrations of compound C-16 with H2O2 as the oxygen source. Irradiation condition: 0.5 W / cm² 2 Irradiate with a 660 nm laser for 10 min.

[0069] Figure 5 Different concentrations of compound C-16 aqueous solutions were tested at 0.5 W / cm². 2 Infrared thermal imaging image showing the temperature change over time under 660 nm laser irradiation.

[0070] Figure 6 Figure 1 shows the photothermal properties of compound C-16; (A) Aqueous solutions of compound C-16 at different concentrations at 0.5 W / cm². 2 (A) Temperature change over time under 660 nm laser irradiation; (B) Temperature change over time of 50 μM compound C-16 aqueous solution under 660 nm laser irradiation at different powers; (C) Temperature change over time of 200 μM compound C-16 aqueous solution after five photothermal cycles, with irradiation conditions of 0.5 W / cm². 2 Irradiate with a 660 nm laser for 5 minutes, then turn off the laser and cool for 10 minutes. Repeat this process five times.

[0071] Figure 7 Photographs of bacterial colonies after treatment with compound C-16 at a concentration of 50 μM and the control group.

[0072] Figure 8 Figure 1 shows the phototherapy killing effect of the control group and different concentrations of compound C-16 on Staphylococcus aureus and Escherichia coli.

[0073] Figure 9 The figure shows the results of hemolysis experiments with different concentrations of compound C-16.

[0074] Figure 10 The images show the wound healing status of diabetic mice; (A) wound healing area and (B) fluorescence imaging monitoring. Detailed Implementation

[0075] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0076] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0077] Example 1: Preparation of compound C-16

[0078]

[0079] Step 1: Under nitrogen protection, add anhydrous deoxytoluene (9 mL), Pd2(dba)3 (0.0549 g, 0.06 mmol), and P to a 100 mL round-bottom flask. t Bu3 (0.12 mmol, 10% by weight solution in n-hexane). The round-bottom flask was fixed and its airtightness checked. N2 was continuously introduced to maintain an anaerobic environment, and the reaction was stirred at room temperature for 20 min. Then, compound C-16-1 (1.380 g, 3.0 mmol), 2-bromothiophene (1.272 g, 7.8 mmol), and sodium tert-butoxide (1.153 g, 12.0 mmol) were added to the system, and the mixture was heated to reflux under nitrogen protection. After 5 h of reaction, the reaction was monitored for completeness by thin-layer chromatography (TLC) with petroleum ether (PE):ethyl acetate (EA) = 95:5. The solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using PE:EA = 20:1 as eluent. After rotary evaporation to remove the solvent, a dark red powder crude intermediate C-16-2 was obtained and used directly in the next reaction.

[0080] Step 2: Under nitrogen protection at 0 °C, phosphorus oxychloride (0.388 g, 2.53 mmol) was slowly added dropwise to a mixture of intermediate C-16-2 (1.246 g, 2.3 mmol) and anhydrous N,N-dimethylformamide (7.85 mL) while stirring. The reaction was continued at 0 °C for 4 h, followed by a reaction at room temperature for 1 h. The reaction mixture was poured into a saturated Na₂CO₃ aqueous solution, resulting in a yellow-orange precipitate. The aqueous phase was extracted with EA, and the organic phase was washed successively with Na₂CO₃ aqueous solution and water. After drying with anhydrous magnesium sulfate, the mixture was filtered, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using PE:EA = 5:1 as the eluent to obtain intermediate C-16-3, a yellow solid powder weighing 1.037 g, which was directly used in the next reaction.

[0081] Step 3: Add ethyl acetoacetate (112 μL, 0.72 mmol) and BF3 to a 50 mL flask. Et₂O (99 μL, 0.788 mmol) was dissolved in 2 mL of ethyl acetate and heated in air at 50–60 °C for 30 min. Intermediate C-16-3 (1.025 g, 1.80 mmol) and B(n-OBu)₃ (0.486 mL, 1.8 mmol) were dissolved in 7 mL of ethyl acetate, and this solution was injected into the mixture using a syringe. The reaction was continued at 50–60 °C for 30 min under nitrogen protection. Then, the first portion of n-butylamine (BuNH₂) (29 μL, 0.288 mmol) was slowly added dropwise to the reaction mixture, and the reaction was heated for 6 h. Finally, the second portion of n-butylamine (14 μL, 0.144 mmol) was added, and the mixture was heated at 50–60 °C overnight. After the reaction was complete, all solvent was removed by rotary evaporation. The crude product was purified by rapid silica gel column chromatography (PE:DCM = 1:1-1:3), followed by further purification through multiple precipitations in a PE / dichloromethane (DCM) mixture to obtain compound C-16, a dark blue powder, 607 mg. ESI-MS m / z : calcd. forC 88 H 61 BF2N2O4S2[M] + •, 1322.413; found, 1322.425. Elemental analysis: C 88 H 61BF2N2O4S2, calculated values ​​(%): C, 79.87; H, 4.65; B, 0.82; F, 2.87; N, 2.12; O, 4.84; S, 4.85; measured values: C, 79.90; H, 4.62; B, 0.81; F, 2.89; N, 2.13; O, 4.83; S, 4.88.

[0082] Example 2: Preparation of compound C-2

[0083]

[0084] Step 1: Replace precursor compound C-16-1 in Step 1 of Example 1 with C-2-1, and adjust the raw material ratio and Pd2(dba)3 / P t The Bu3 catalytic system, anhydrous toluene solvent, and reaction conditions (nitrogen protection, reflux at 110-120 °C for 5 h) were completely consistent with those in Example 1. After the reaction, the reaction was monitored by TLC (PE:EA=95:5), and purified by column chromatography with PE:EA=20:1 as the eluent to obtain the C-2-2 intermediate, which was directly used in the next step.

[0085] Step 2: Following the procedure in Step 2 of Example 1 exactly, the intermediate C-2-2 obtained in Step 1 was subjected to a formylation reaction to finally obtain the C-2-3 intermediate (yield 55%).

[0086] Step 3: The boron ring closure reaction was carried out exactly as described in Step 3 of Example 1, following the same reagent dosages, reaction temperature, and purification method. The final product was compound C-2, a dark blue powder, with a yield of 39%. ESI-MS m / z : calcd. forC 42 H 65 BF2N2O4S2[M] + •, 774.44; found, 774.44. Elemental analysis: C 42 H 65 BF2N2O4S2, calculated values ​​(%): C, 65.10; H, 8.46; N, 3.62; measured values: C, 65.47; H, 8.40; N, 3.58.

[0087] Example 3: Preparation of compound C-4

[0088]

[0089] Step 1: Replace precursor compound C-16-1 in Step 1 of Example 1 with C-4-1, and adjust the raw material ratio and Pd2(dba)3 / P tThe Bu3 catalytic system, anhydrous toluene solvent, and reaction conditions (nitrogen protection, reflux at 110-120 °C for 5 h) were completely consistent with those in Example 1. After the reaction, the reaction was monitored by TLC (PE:EA=95:5), and purified by column chromatography with PE:EA=20:1 as the eluent to obtain the C-4-2 intermediate, which was directly used in the next step.

[0090] Step 2: Following the procedure in Step 2 of Example 1 exactly, the intermediate C-4-2 obtained in Step 1 was subjected to a formylation reaction to finally obtain the C-4-3 intermediate (yield 55%).

[0091] Step 3: The boron ring closure reaction was carried out exactly as described in Step 3 of Example 1, following the same reagent dosages, reaction temperature, and purification method. The final product was compound C-4, a dark blue powder, with a yield of 39%. ESI-MS m / z : calcd. for C 42 H 33 BF2N2O4S2[M] + •, 742.19; found, 742.19. Elemental analysis: C 42 H 33 BF2N2O4S2, calculated values ​​(%): C, 67.93; H, 4.48; N, 3.77; measured values: C, 67.89; H, 4.40; N, 3.72.

[0092] Example 4: Preparation of compound C-9

[0093]

[0094] Step 1: Replace precursor compound C-16-1 in Step 1 of Example 1 with C-9-1, and adjust the raw material ratio and Pd2(dba)3 / P t The Bu3 catalytic system, anhydrous toluene solvent, and reaction conditions (nitrogen protection, reflux at 110-120 °C for 5 h) were completely consistent with those in Example 1. After the reaction, the intermediate C-9-2 was obtained by column chromatography with TLC monitoring (PE:EA=95:5) and PE:EA=20:1 as the eluent, and was directly used in the next step.

[0095] Step 2: Following the procedure in Step 2 of Example 1 exactly, the intermediate C-9-2 obtained in Step 1 was subjected to a formylation reaction to finally obtain intermediate C-9-3 (yield 55%).

[0096] Step 3: The boron ring closure reaction was carried out exactly as described in Step 3 of Example 1, following the same reagent dosages, reaction temperature, and purification method. The final product was compound C-9, a dark blue powder, with a yield of 39%. ESI-MS m / z : calcd. for C42 H 29 BF2N2O6S2[M] + •, 770.15; found, 770.14. Elemental analysis: C 42 H 29 BF2N2O6S2, calculated values ​​(%): C, 65.46; H, 3.79; N, 3.64; measured values: C, 65.56; H, 3.74; N, 3.61.

[0097] Example 5: Preparation of compound C-13

[0098]

[0099] Step 1: Replace precursor compound C-16-1 in Step 1 of Example 1 with C-13-1, and adjust the raw material ratio and Pd2(dba)3 / P t The Bu3 catalytic system, anhydrous toluene solvent, and reaction conditions (nitrogen protection, reflux at 110-120 °C for 5 h) were completely consistent with those in Example 1. After the reaction, the intermediate C-13-2 was obtained by column chromatography with TLC monitoring (PE:EA=95:5) and PE:EA=20:1 as the eluent, and was directly used in the next step.

[0100] Step 2: Following the procedure in Step 2 of Example 1 exactly, the intermediate C-13-2 obtained in Step 1 was subjected to a formylation reaction to finally obtain intermediate C-13-3 (yield 55%).

[0101] Step 3: The boron ring closure reaction was carried out exactly as described in Step 3 of Example 1, following the same reagent dosages, reaction temperature, and purification method. The final product was compound C-13, a dark blue powder, with a yield of 39%. ESI-MS m / z : calcd. for C 58 H 41 BF2N2O4S2[M] + •, 942.26; found, 942.26. Elemental analysis: C 58 H 41 BF2N2O4S2, calculated values ​​(%): C, 73.88; H, 4.38; N, 2.97; measured values: C, 73.66; H, 4.32; N, 3.03.

[0102] Example 6: Phototherapy Core Performance Testing of Compounds

[0103] Compounds C-2, C-4, C-9, C-13, and C-16 obtained in Examples 1 to 5 were prepared into 50 μM aqueous solutions containing 1% DMSO by volume. Their core phototherapy performance was then tested: the photothermal conversion efficiency exceeded 0.5 W / cm². 2 The sample solution was irradiated with a 660 nm laser for 5 min, and the temperature change curve recorded by an infrared thermal imager was used for calculation. The type I ROS generation efficiency was measured using the TMB colorimetric method with Kcat / Km as the indicator. The hemolysis rate was tested using the rabbit red blood cell suspension method, and the hemolysis rate of each compound at a concentration of 50 μM was measured after incubation at 37℃ for 1 h. The test results of each compound are shown in Table 1.

[0104] Table 1

[0105]

[0106] Performance comparison and optimization of compounds in each embodiment: Compounds C-2, C-4, C-9, C-13, and C-16 were tested for optical properties (near-infrared emission), phototherapy activity (reactive oxygen species generation, photothermal conversion efficiency), and biocompatibility (solubility in wound simulation media). Compound C-16, with the best overall performance, was selected as the test subject for subsequent phototherapy antibacterial performance testing.

[0107] Example 7: DLS particle size and zeta potential testing of C-16

[0108] This embodiment uses a Malvern Zetasizer Nano series instrument and its matching sample cell to test the DLS particle size distribution and Zeta potential of the dispersion of compound C-16 of this invention. An ethanol solution (200 μM concentration) and an aqueous solution of compound C-16 (containing 1% DMSO, with a compound C-16 concentration of 200 μM) were prepared. For DLS testing, 1 mL of the above sample containing compound C-16 was measured, ultrasonically dispersed for 15 min, injected into the sample cell, and placed in the instrument. The particle size and distribution data were scanned and recorded at 25°C. The Zeta potential test was similar; the instrument automatically calibrated and calculated and output the Zeta potential value. The test results are as follows: Figure 1 As shown. Figure 1 Experimental results show that compound C-16 exhibits self-assembly behavior in aqueous solution, and the aggregated DLS particle size is approximately 170 nm. Figure 1 (B)); its Zeta potential in water is -21.4 mV ( Figure 1 (A) This property is presumably related to the material’s excellent photothermal effect.

[0109] Example 8: UV-Vis absorption and fluorescence spectroscopy of compound C-16

[0110] In this embodiment, an ultraviolet-visible spectrophotometer, a fluorescence spectrophotometer, and a matching 1 cm × 1 cm quartz cuvette were used to test the absorption and fluorescence spectral characteristics of compound C-16. Figure 2 In Figures (A) and (B), solutions of compound C-16 in different solvents (the concentration of compound C-16 is 200 μM). The solvents are water (containing 1% DMSO by volume), n-hexane, toluene, EA, acetonitrile (MeCN), and ethanol. During UV-Vis spectroscopy, 3 mL of solvent [organic solvent or water (containing 1% DMSO by volume)] is accurately measured and placed in a cuvette. After recording the baseline, the C-16 solution is scanned and the absorption spectrum is recorded in the 200-1000 nm wavelength range. The molar absorptivity reaches 8 × 10⁻⁶. 4 L·mol -1 ·cm -1 During fluorescence emission spectroscopy testing, the fluorescence emission spectra of the sample solution [aqueous solutions of different concentrations (containing 1% DMSO by volume)] were scanned and recorded in the 700-1000 nm range. The test results are as follows: Figure 2 As shown in (C). Figure 2 The test results (C) show that aqueous solutions of compound C-16 at different concentrations exhibit a red shift in fluorescence wavelength with concentration. The maximum absorption wavelength of a 200 μM aqueous solution of C-16 (containing 1% DMSO by volume) is 692 nm, the maximum fluorescence emission wavelength is 845 nm, and the Stokes shift reaches 153 nm. Compared with compounds reported in the literature, compound C-16 shows a significant red shift in both absorption and emission wavelengths. This characteristic can enhance the penetration depth into biological tissues and fully meet the application requirements of biophototherapy.

[0111] Example 9 Photodynamic performance test of compound C-16

[0112] Compound C-16 was determined by ESR spectroscopy at 0.5 W / cm². 2 The types of ROS generated under 660 nm laser irradiation for 10 min were analyzed, and their ESR results in PBS aqueous solution were used as a control. When TEMP was used as a trapping agent, the ESR spectrum showed a characteristic 1:1:1 triplet signal of 2,2,6,6-tetramethylpiperidine nitroxide radical (TEMPO), proving that compound C-16 can generate ROS. 1 O2 ( Figure 3 (A)); When DMPO was used as the trapping agent, two characteristic signals were detected, one of which was a 1:1:1:1 quartet (DMPO-O2). - The characteristic peaks of the adduct indicate the formation of ·O2.- The second is a 1:2:2:1 quartet (characteristic peak of DMPO-OH adduct), proving the formation of ·OH ( Figure 3 (B) and (C)). In summary, compound C-16 can simultaneously generate three key ROS: including a type I PDT-related ·O2. - ·OH and type II PDT related 1 O2 has excellent potential as a photosensitizer.

[0113] To further verify the aforementioned properties of compound C-16, its photodynamic oxidation performance was investigated through in vitro experiments. 3,3′,5,5′-Tetramethylbenzidine (TMB) was used as an indicator, which can be oxidized by ROS to generate the colorimetric product oxidized TMB (oxTMB), with characteristic absorption peaks at 652 nm and 450 nm, respectively. O2 and H2O2 were used as oxygen sources, respectively, at a concentration of 0.5 W / cm². 2 A 660 nm laser was used as the light source to irradiate an aqueous mixture of compounds C-16 and TMB (containing 1% DMSO by volume). Since compound C-16 itself exhibits strong absorption at 652 nm, to avoid spectral overlap interfering with the observation of absorbance changes in oxTMB, the absorbance change of the aqueous mixture at 450 nm was measured. The test results are as follows: Figure 4 As shown. Figure 4 The test results showed that the absorbance change (A-A0) of the aqueous mixture at 450 nm increased significantly in a concentration-dependent manner. Meanwhile, as the illumination time increased, the absorbance peak intensity of the mixture of TMB and compound C-16 gradually increased, indicating that compound C-16 has strong photodynamic oxidation performance in a physiological pH environment (pH=7-8), and can efficiently generate ROS and oxidize the substrate TMB under illumination.

[0114] Example 10: Photothermal Performance Test of Compound C-16

[0115] The photothermal properties of compound C-16 were systematically tested under the following conditions: laser power density 0.5 W / cm². 2 The wavelength was 660 nm, and the sample was a 0.1 mL aqueous solution of compound C-16 at different concentrations (containing 1% DMSO by volume). Photothermal images of the aqueous solution were captured using an infrared camera as shown below. Figure 5 As shown. Figure 5 The test results showed that when the concentration of compound C-16 increased from 6.125 μM to 200 μM, the sample temperature gradually increased with increasing concentration within 5 min of laser irradiation. The maximum temperature and the heating rate both showed a concentration dependence, confirming that the compound has a good photothermal effect.

[0116] Figure 6 (A) shows the photothermal performance test results of aqueous solutions of compound C-16 at different concentrations. The highest temperatures reached after 5 minutes of laser irradiation for aqueous solutions of compound C-16 in the concentration range of 6.125-200 μM were 44.4 ℃, 56.5 ℃, 76.1 ℃, 81.4 ℃, 85.4 ℃, and 85.9 ℃, respectively. When the concentration of aqueous solutions of compound C-16 was greater than or equal to 25 μM, the samples could all heat up to above 70 ℃ within 5 minutes. This temperature is sufficient to effectively kill bacteria, and all concentrations of samples exhibited excellent heating rates. Figure 6 (B) shows the heating-cooling curve of a 50 μM aqueous solution of compound C-16. Based on the data from this curve, the photothermal conversion efficiency of the aqueous solution of compound C-16 is calculated to be 40%. Figure 6 (C) shows the photothermal cycling stability test results of the 200 μM concentration aqueous solution of compound C-16. After five cycles of "5 min laser irradiation - 10 min shutdown", the sample still maintained a stable heating rate, and the temperature could rise to above 83℃ within 5 min of each cycle, indicating that it has good thermal reproducibility and photothermal stability.

[0117] The above experimental results show that compound C-16 can efficiently convert light energy into heat energy and has excellent photothermal properties.

[0118] Example 11 Plate antibacterial performance test of compound C-16

[0119] In this embodiment, Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria) were used as test strains. The phototherapy antibacterial properties of compound C-16 were evaluated using the plate count method. The instrument and reagents included 0.5 W / cm². 2 The equipment included a 660 nm laser, LB liquid and solid culture plates, a 100 μM aqueous solution of compound C-16, and sterile consumables. Both *S. aureus* and *E. coli* strains were cultured in liquid medium at 37°C and 300 r / min for 24 h, with an initial bacterial concentration of approximately 10 μM. 9 CFU / mL, diluted to 10 3 CFU / mL for later use. The antibacterial test consisted of 4 groups (200 μL bacterial suspension per group): (1) Control group (Ctrl, Light) - (1) No compound C-16, no light exposure, 200 μL PBS added); (2) Light control group (Ctrl, Light) + (3) C-16 group (Light) -Add 200 μL of compound C-16 solution, the final concentration of compound C-16 is 100 μM); (4) C-16 + light group (Light + Add 200 μL of compound C-16 solution (final concentration of compound C-16: 100 μM) and irradiate with a xenon lamp for 15 min. Take 300 μL of each treated sample and plate them. S. aureus and E. coli strains were inoculated onto LB agar plates and incubated at 37℃ for 24 h before counting. Results showed that the bactericidal activity of compound C-16 alone (without light) was almost negligible. After light irradiation, S. aureus and E. coli colonies were almost completely eliminated. Compound C-16 at concentrations of 50 μM and above showed a bactericidal rate >99% against both bacteria. Figure 7 Furthermore, concentration gradient experiments determined that the effective antibacterial concentration of compound C-16 is 50 μM and above. Figure 8 Hemolysis experiments showed that the hemolysis rate of compound C-16 at concentrations of 200 μM and below was less than 5%. Figure 9 ).

[0120] The above test results indicate that compound C-16, as a near-infrared photosensitizer, achieves highly efficient antibacterial activity by disrupting bacterial membranes and through photothermal / photodynamic synergy. It also exhibits good biocompatibility at effective concentrations, making it suitable for the treatment of diabetic wounds.

[0121] Example 12 Chronic wound healing in diabetic mice

[0122] In this embodiment, a diabetic mouse model was constructed using streptozotocin (STZ), and the antibacterial and wound-healing properties of compound C-16, which exhibits synergistic PTT and PDT effects, were tested on diabetic mouse wounds. Specific pathogen-free (SPF) ICR mice were used as experimental subjects. Reagents included STZ, PBS, and a 100 μM aqueous solution of compound C-16 (containing 1% DMSO by volume). The instrument used was a 0.5 W / cm² instrument. 2 A 660 nm laser, a blood glucose meter, and a ruler were used. Mice were fasted for 12 hours and then injected intraperitoneally with 50 mg / kg STZ solution. Successful modeling was indicated by three consecutive fasting blood glucose tests ≥16.7 mM. After hair removal from the back, a 10 mm diameter circular full-thickness wound was aseptically created, and a 1×10⁻⁶ concentration of STZ solution was applied to the wound. 7 20 μL of S. aureus bacterial suspension (CFU / mL) was divided into two groups (5 animals per group): ① Control group: wounds were treated with 200 μL PBS; ② Experimental group: wounds were treated with 200 μL 100 μM compound C-16 aqueous solution. Both groups were administered the drug only on days 1-3, and were irradiated with a xenon lamp for 10 min daily from days 1-7. The test results are as follows. Figure 10As shown. Under light irradiation, compound C-16 exerts a PTT-PDT effect, achieving local antibacterial and repair-promoting effects. After 14 days of treatment, the residual wound area in the control group was 18.7%, while that in the experimental group was only 3.6%. After 14 days, the wounds in the experimental group were almost completely healed, and the healing effect in the experimental group was 5 times faster than that in the control group. Figure 10 (A) Simultaneously, using a small animal in vivo imaging system, the amount of residual material at the wound site can be observed in real time through near-infrared fluorescence intensity in the 840 nm emission region (excitation at 745 nm), thus determining the effectiveness of treatment and the extent of material penetration. Figure 10 (B) This test result indicates that the material has the integrated diagnostic and therapeutic capabilities for diabetic chronic wounds, can remain stably in animal wounds for 14 days, and exert phototherapy effects.

[0123] In summary, the compounds of this invention accelerate the healing of diabetic wounds through the synergistic antibacterial effect of PTT-PDT under xenon lamp irradiation, and have clinical application value.

[0124] The exemplary embodiments of the present invention have been described above. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A DAD-type near-infrared organic molecule, characterized in that, It has the structure shown in the following general formula (I): （I） Where R1 and R2 are the same or different, and are independently selected from C. 1-12 Alkyl, C 6-14 aryl or ;R a Selected from C 6-14 Aryl; Alternatively, R1 and R2, together with their connected N, form a ring, constituting a non-substitutable structure. E is selected from O, S or Se.

2. The DAD-type near-infrared organic molecule according to claim 1, characterized in that, R1 and R2 may be the same or different, and are independently selected from C. 1-6 alkyl, , , , ; R a Selected from C 6-14 Aryl; n is 0.

3. The DAD-type near-infrared organic molecule according to claim 1, characterized in that, R1 and R2 may be the same or different, and are independently selected from the following groups: ； Alternatively, R1, R2, and their associated N form a ring, together constituting the following functional group: , , .

4. The DAD-type near-infrared organic molecule according to claim 1, characterized in that, The structure shown in equation (I) is selected from one of the following structures: 。 5. The method for preparing the DAD-type near-infrared organic molecule according to any one of claims 1-4, characterized in that, Includes the following steps: Wherein, R1 and R2 have the definitions described in any one of claims 1-4; Compound M3 reacts with ethyl acetoacetate and boron trifluoride diethyl ether to give the structure shown in formula (I).

6. A pharmaceutical composition, characterized in that, Includes the DAD-type near-infrared organic molecule as described in any one of claims 1-4.

7. The pharmaceutical composition according to claim 6, characterized in that, The pharmaceutical composition is a bactericide.

8. Use of the DAD-type near-infrared organic molecule according to any one of claims 1-4 in the preparation of a medicament for treating chronic wound healing.

9. Use of the DAD-type near-infrared organic molecule according to any one of claims 1-4 in the preparation of bactericides.

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