Novel near-infrared two-region emission aggregation-induced emission material, preparation method and application thereof

Abstract

The application discloses a novel near-infrared two-region aggregation-induced emission material, a preparation method and application thereof, and has the following general structure: wherein Ar is R1 and R2 are independently selected from -t-Bu, -OC6H 13 The application uses triphenylamine derivative structural units as electron donors of a molecular system, and uses 6,7-diphenyl-[1,2,5]thiadiazole[3,4-g]quinoxaline or indene ketone condensation [1,2,5]thiadiazole[3,4-g]quinoxaline structural units as electron acceptors to construct a novel photothermal material with near-infrared two-region aggregation-induced emission properties. The compound structure of the application is clear, the synthesis method is simple, and biological activity experiments show that the application has a good application prospect in fluorescence-photoacoustic-photothermal imaging guided photothermal-photodynamic synergistic tumor ablation treatment.

Description

Technical Field

[0001] This invention relates to the field of fluorescence imaging molecular probe technology, specifically to a novel near-infrared II region aggregation-induced emission material, its preparation method, and its applications. Background Technology

[0002] Aggregation-induced emission molecules (AIEgens) provide crucial material support for integrated phototherapy technologies, primarily due to the precise control of energy dissipation pathways achieved through molecular design, enabling "on-demand" material design. AIEgens with a propeller conformation stack randomly under physiological conditions, effectively suppressing intramolecular / intermolecular stacking and exhibiting aggregation-enhanced fluorescence imaging (FLI). Secondly, the numerous rotor or oscillator groups on the AIEgen molecular backbone allow the molecules to maintain local rotation / vibration even in a tightly packed state. The molecules generate heat through non-radiative dissipation pathways, making them suitable for photothermal imaging (PTI), photoacoustic imaging (PAI), and photothermal therapy (PTT). Furthermore, AIEgens molecules with strong DA effects, upon photoexcitation, dissipate the energy of the excited state via S1-T1, generating highly oxidizing reactive oxygen species for photodynamic therapy (PDT). Therefore, aggregation-induced emission materials are an ideal platform for constructing multifunctional integrated phototherapy technologies.

[0003] Currently, AIEgens possess greater penetration depth in the second near-infrared biological window (NIR-II, 1000-1700 nm) used for surgical navigation, which is beneficial for obtaining higher resolution fluorescence imaging. Unlike expanding the degree of skeletal conjugation to prolong absorption / emission, near-infrared II aggregation-induced emission molecules with DAD-type structures containing strong electron-rich donors (D) and strong electron-withdrawing acceptors (A) have attracted considerable attention due to their good photostability. Nevertheless, the limited acceptor units currently available for constructing high-performance NIR-II-AIEgens fluorescent molecules restrict the design and functional expansion of NIR-II-AIEgens.

[0004] Therefore, existing technologies still need further improvement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to enrich and expand the existing library of near-infrared II aggregation-induced emission molecular acceptor backbones, which have limited selection, short absorption wavelength and limited functionality.

[0006] The purpose of this invention is to provide a novel near-infrared II aggregation-induced emission material, its preparation method, and its application. The compound structure of this invention is well-defined, the synthesis method is simple, and bioactivity experiments show that it has good application prospects in photothermal-photodynamic synergistic tumor ablation therapy guided by fluorescence-photoacoustic-photothermal imaging.

[0007] The general structural formula of this type of compound provided by the present invention is as follows:

[0008]

[0009] Where Ar is R1 and R2 are independently selected from -t-Bu, -OC6H 13 , One of them.

[0010] The preparation method of this type of novel near-infrared II aggregation-induced emission material based on thiadiazoquinoxaline electron acceptor derivatives includes the following steps:

[0011] Compound II and a reducing agent were added sequentially to an acid reagent, and the reaction was carried out at 80°C under an inert gas atmosphere to obtain a reaction solution; the structural formula of compound II is:

[0012] R1 and R2 are independently selected from -t-Bu, -OC6H 13 , One of them; the inert gas used in the inert atmosphere can be an inert gas such as helium, nitrogen or argon.

[0013] After the reaction was completed, the mixture was cooled to room temperature and a saturated sodium chloride solution was added. The mixture was then extracted with dichloromethane, and the organic phases were combined, dried, and concentrated under reduced pressure to obtain the crude product. The room temperature mentioned here and below refers to an ambient temperature of 24–25°C.

[0014] The crude product does not need to be purified. It is dissolved in a small amount of chloroform, and an appropriate amount of glacial acetic acid is added as a reaction solvent. An aromatic diketone is added to carry out a condensation reaction to obtain a blue-green solution.

[0015] After the reaction was completed and cooled to room temperature, a saturated sodium chloride solution was added, and the mixture was extracted with dichloromethane. The organic phases were then combined, dried, and concentrated under reduced pressure to obtain the crude product.

[0016] The crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane as the eluent to obtain a novel near-infrared II aggregation-induced emission material.

[0017] Optionally, the reducing agent used in the reduction process is selected from any one of H2, Zn, Fe, LiAlH4, KBH4 and NaBH4.

[0018] Optionally, the acid reagent used in the reduction process is an organic acid, which is selected from any one of acetic acid, propionic acid, and n-butyric acid.

[0019] Optionally, the temperature of the reflux stirring process in the reduction process is 70–100°C, and the reaction time is 2–10 h. For example, 70°C–80°C, 80°C–90°C, 90°C–100°C; and the reaction time is 2 h–4 h, 4 h–6 h, 6 h–8 h, or 8 h–10 h.

[0020] Optionally, the molar ratio of the intermediate product to the aromatic diketone during the condensation process is 1:2.5 to 1:3.5.

[0021] Optionally, the organic acid reagent used in the condensation process is selected from any one of acetic acid, propionic acid, and butyric acid.

[0022] Optionally, the temperature of the stirring reflux during the condensation process is 70–100°C, and the reaction time is 2–10 h. For example, 70°C–80°C, 80°C–90°C, 90°C–100°C; and the reaction time is 2 h–4 h, 4 h–6 h, 6 h–8 h, or 8 h–10 h.

[0023] The reaction solution was extracted using dichloromethane, and the organic phases in the extracted reaction solution were then combined.

[0024] The reaction solution with combined organic phases was dried using anhydrous sodium sulfate, and the dried reaction solution was then concentrated under reduced pressure to obtain the crude product.

[0025] The application of a novel near-infrared II aggregation-induced emission material as described above in the preparation of a photothermal-photodynamic synergistic ablation therapy for malignant tumors.

[0026] Beneficial effects: Compared with the prior art, the near-infrared II aggregation-induced emission molecule provided by this invention is an aggregation-induced emission material with a novel DAD structure. This type of material uses triphenylamine derivative structural units as electron donors in the molecular system and 6,7-diphenyl-[1,2,5]thiadiazole[3,4-g]quinoxaline or indanone condensed [1,2,5]thiadiazole[3,4-g]quinoxaline structural units as electron acceptors to construct a novel photothermal material with near-infrared II aggregation-induced emission properties. The aggregation-induced emission material generates excellent photothermal conversion and produces reactive oxygen species under 808nm laser irradiation, causing tumor cell death. In the near-infrared II fluorescence-photoacoustic dual-modal imaging mode, the photothermal-photodynamic synergistic tumor therapy can effectively kill tumor cells, thereby inhibiting tumor growth or tumor ablation. Attached Figure Description

[0027] Figure 1This is the 1H NMR spectrum of compound II-a prepared in Example 1 of this invention;

[0028] Figure 2 This is the carbon NMR spectrum of compound II-a prepared in Example 1 of this invention;

[0029] Figure 3 This is a high-resolution mass spectrum of compound II-a prepared in Example 1 of this invention;

[0030] Figure 4 This is the 1H NMR spectrum of compound Ia prepared in Example 1 of this invention;

[0031] Figure 5 This is the carbon NMR spectrum of compound Ia prepared in Example 1 of this invention;

[0032] Figure 6 This is a high-resolution mass spectrometer of compound Ia prepared in Example 1 of this invention;

[0033] Figure 7 This is the 1H NMR spectrum of compound Ib prepared in Example 2 of this invention;

[0034] Figure 8 This is the carbon NMR spectrum of compound Ib prepared in Example 2 of this invention;

[0035] Figure 9 This is a high-resolution mass spectrometer of compound Ib prepared in Example 2 of this invention;

[0036] Figure 10 These are the ultraviolet absorption and fluorescence emission spectra of compounds Ia and Ib prepared in Examples 1 and 2 of this invention;

[0037] Figure 11 These are aggregation-induced fluorescence enhancement fold maps of compounds Ia and Ib prepared in Examples 1 and 2 of this invention;

[0038] Figure 12 This is an experimental diagram showing the dark toxicity and photothermal-photodynamic killing effect of the nanoparticles of compound Ib prepared in Example 2 of this invention on 4T1 cells.

[0039] Figure 13 These are in vivo imaging and treatment experiments of the nanoparticles of compound Ib prepared in Example 2 of this invention in 4T1 tumor mice;

[0040] Figure 14 This is an experimental diagram showing the photothermal-photodynamic killing effect of the nanoparticles of compound Ib prepared in Example 2 of this invention on 4T1 tumor mice;

[0041] Figure 15This is an experimental diagram showing the photothermal-photodynamic killing effect of the nanoparticles of compound Ib prepared in Example 2 of this invention on 4T1 tumor mice. Detailed Implementation

[0042] The present invention is further illustrated below by way of embodiments, but these embodiments are not intended to limit the invention to their scope. Implementation methods not specifically described in the following embodiments are selected according to conventional methods and conditions or the product specification. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0043] Example 1

[0044]

[0045] Step 1) Synthesis of compound II-a

[0046] To a 15 mL tetrahydrofuran solution of III-a (436.4 mg, 1 mmol), butyllithium solution (0.6 mL, 1.5 mmol, 2.5 M) was added dropwise, and the reaction was carried out at -78 °C under a nitrogen atmosphere for 1 hour. Tributyltin chloride (0.32 mL, 1.5 mmol) was then added, and the reaction was continued at -78 °C under a nitrogen atmosphere for 0.5 hours, followed by a change to room temperature. After the reaction was complete, saturated potassium chloride was added to quench the reaction, followed by extraction with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, filtered under reduced pressure, and concentrated. The solution was used directly for the next reaction without further purification. In a 25 mL Schlenk reaction tube, IV (100 mg, 0.26 mmol), tetrakis(triphenylphosphine)palladium (30 mg, 0.026 mmol), and redistilled toluene (5 mL) were added. The mixture was heated to reflux and reacted for 15 hours. After the reaction was complete, saturated potassium fluoride was added to quench the reaction. The mixture was cooled to room temperature and extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, filtered under reduced pressure, and concentrated to obtain the crude product. Column chromatography (using dichloromethane / petroleum ether as eluent, volume ratio 1:4) yielded a purple solid product in 78% yield. 1 H NMR (600MHz, CDCl3) δ7.39 (d, J = 8.9 Hz, 2H), 7.34 (d, J = 8.7 Hz, 4H), 7.15 (d, J = 8.6 Hz, 4H), 7.08 (d, J = 8.8 Hz, 2H), 1.33 (s, 18H). 13C NMR (151MHz, CDCl3) δ153.26,150.11,147.36,143.80,142.17,130.11,127.75,126.40,125.62,121.36,119.64,34.42,31.40.HRMS(MALDI-TOF)calculated for:C 58 H 60 N6O4S[M] + :936.43913,found:936.43640. The proton NMR spectrum, carbon NMR spectrum, and high-resolution mass spectra of compound II-a are as follows: Figure 1 , Figure 2 and Figure 3 As shown.

[0047] Step 2) Synthesis of compound Ia

[0048] II-a (468.6 mg, 0.5 mmol) and reduced iron powder (840 mg, 15 mmol) were added to a 50 mL single-necked flask. Glacial acetic acid / chloroform (25 mL, 4:1 v / v) was added, and the mixture was purged with nitrogen 4–6 times. The mixture was heated to 90 °C and reacted for 5 hours. After the reaction, the reaction solution was cooled to room temperature, and water and dichloromethane were added for extraction. The combined organic phases were dried over anhydrous sodium sulfate, filtered under reduced pressure, and concentrated to obtain the crude product, which could be used directly in the next reaction without purification. The crude product was dissolved in a small amount of chloroform and added to a 50 mL single-necked flask. Glacial acetic acid (25 mL) and diphenyl diethyl ketone (42 mg, 0.2 mmol) were added, and the mixture was purged with nitrogen 4–6 times. The mixture was heated to 90 °C and reacted for 2 hours. After the reaction was completed, the reaction solution was cooled to room temperature, and water and dichloromethane were added for extraction. The organic phases were combined and dried with anhydrous sodium sulfate. The mixture was filtered under reduced pressure and concentrated to obtain the crude product. The crude product was subjected to column chromatography (dichloromethane / petroleum ether as eluent, volume ratio 2:1) to obtain a blue solid product with a yield of 70%. 1 H NMR (500MHz, CDCl3) δ7.96(d,J=8.7Hz,4H),7.73-7.60(m,4H),7.43-7.36(m,2H),7.32(dd,J=8.3,6.3Hz,16H),7.20(d,J=8.2Hz,8H),1.35(s,36H). 13C NMR (151MHz, CDCl3) δ153.16,152.54,148.31,146.18,144.76,138.61,136.00,133.87,130.07,12 9.44,128.49,128.14,127.39,126.09,124.76,120.74,34.35,31.46.HRMS(MALDI-TOF):calcd.for C 72 H 71 N6S[M+H] + :1051.54554,found:1051.54527. The proton NMR spectrum, carbon NMR spectrum, and high-resolution mass spectra of compound II-a are as follows: Figure 4 , Figure 5 and Figure 6 As shown.

[0049] Example 2

[0050] Synthesis of compound Ib

[0051]

[0052] Step 3) Synthesis of compound Ib

[0053] II-a (468.6 mg, 0.5 mmol) and reduced iron powder (840 mg, 15 mmol) were added to a 50 mL single-necked flask. Glacial acetic acid / chloroform (25 mL, 4:1 v / v) was added, and the mixture was purged with nitrogen 4–6 times. The mixture was heated to 90 °C and reacted for 5 hours. After the reaction, the reaction solution was cooled to room temperature, and water and dichloromethane were added for extraction. The combined organic phases were dried over anhydrous sodium sulfate, filtered under reduced pressure, and concentrated to obtain the crude product, which could be used directly in the next reaction without purification. The crude product was dissolved in a small amount of chloroform and added to a 50 mL single-necked flask. Glacial acetic acid (25 mL) and ninhydrin hydrate (35.6 mg, 0.2 mmol) were added, and the mixture was purged with nitrogen 4–6 times. The mixture was heated to 90 °C and reacted for 2 hours. After the reaction was completed, the reaction solution was cooled to room temperature, and water and dichloromethane were added for extraction. The organic phases were combined and dried with anhydrous sodium sulfate. The mixture was filtered under reduced pressure and concentrated to obtain the crude product. The crude product was subjected to column chromatography (dichloromethane / petroleum ether as eluent, volume ratio 2:1) to obtain a blue-green solid product with a yield of 61%. 1H NMR (600MHz, CDCl3) δ8.12(d,J=7.6Hz,1H),7.98(d,J=7.5Hz,1H),7.84(t,J=8.7Hz,4H),7.80(td,J=7.6,0.9Hz, 1H),7.66(dd,J=11.5,4.1Hz,1H),7.35(d,J=8.6Hz,8H),7.26(s,2H),7.25-7.20(m,10H),1.35(d,J=1.7Hz,36H). 13 C NMR (151MHz, CDCl3)δ

[0054] 188.88,154.74,154.25,153.61,150.71,148.34,146.67,146.45,144 .63,144.42,141.20,138.82,137.68,137.42,136.68,134.00,133.56, 133.44,132.92,129.97,126.23,126.18,125.41,125.07,124.59,123.45,120.05,119.66,34.38,34.37,31.45.HRMS(MALDI-TOF):calcd.for C 67 H 65 N6OS[M+H] + :1001.49351,found:1001.49313. The proton NMR spectrum, carbon NMR spectrum, and high-resolution mass spectra of compound II-a are as follows: Figure 7 , Figure 8 and Figure 9 As shown.

[0055] Example 3

[0056] like Figure 10 As shown, Figure 10 The absorption and emission spectra of Ia and Ib in Examples 1 and 2 show that the designed and synthesized molecules Ia and Ib both have near-infrared absorption and near-infrared II fluorescence emission properties.

[0057] like Figure 11 As shown, Figure 11 The figure shows the fluorescence emission intensity variation of Ia and Ib in tetrahydrofuran / water mixed solvent in Examples 1 and 2. As can be seen from the figure, Ia and Ib show obvious fluorescence enhancement as the content of the undesirable solvent water increases, indicating that the synthesized Ia and Ib both have aggregation-induced emission properties.

[0058] like Figure 12 As shown, Figure 12 This image shows the dark toxicity and photothermal-photodynamic killing effect of Ib nanoparticles prepared from near-infrared aggregation-induced emission molecules as described in Example 2 of this invention on 4T1 cells. Figure 12 As can be seen from this, Ib nanoparticles in 40 μg / mL -1 It exhibits low cytotoxicity within the range of 808 nm, and the survival rate of cancer cells drops sharply after irradiation with an 808 nm laser, indicating that Ib nanoparticles have excellent cancer cell killing ability.

[0059] Example 4

[0060] like Figure 13 As shown, Figure 13 The nanoparticles prepared from the Ib synthesized in Example 2 were injected into tumor-bearing mice via tail vein. Multimodal imaging images at different time points after injection were acquired using a small animal imaging system (including fluorescence, photoacoustic, and photothermal imaging). Figure 13 As can be seen, Ib nanoparticles can be well accumulated in tumor tissue in mice. Under 808nm laser irradiation, they exhibit bright near-infrared II fluorescence imaging, photoacoustic imaging, and photothermal imaging. Simultaneously, 24 hours after injection, the tumor site in mice was irradiated with an 808nm laser. Within 10 minutes, the temperature at the tumor site rapidly reached 52.3℃, indicating that Ib nanoparticles have excellent photothermal heating capabilities at the tumor site in tumor-bearing mice after laser irradiation, effectively killing tumor cells and thus inhibiting tumor growth or ablating tumors.

[0061] like Figure 14 and Figure 15 As shown, Figure 14 and Figure 15 The Ib nanoparticles synthesized in Example 2 were injected into tumor-bearing mice via the tail vein. The mice were randomly divided into four groups: a control group (injected only with saline), a group receiving saline injection plus 808nm laser irradiation, and a group receiving only Ib nanoparticle injection. The experimental groups received Ib nanoparticle injection plus 808nm laser irradiation. Mouse growth was subsequently observed, and tumor volume and tumor weight were recorded on day 15.

[0062] The therapeutic effect of Ib nanoparticles on tumor-bearing mice in Example 2 is as follows: Figure 14 and Figure 15 As shown in the figure, the tumors in the experimental group were effectively suppressed, while the tumor volume and weight in the control group increased significantly.

[0063] In summary, this invention provides a novel near-infrared II aggregation-induced emission material, its preparation method, and its application. Using triphenylamine derivative structural units as electron donors in the molecular system and 6,7-diphenyl-[1,2,5]thiadiazole[3,4-g]quinoxaline or indanone condensed [1,2,5]thiadiazole[3,4-g]quinoxaline structural units as electron acceptors, a novel photothermal material with near-infrared II aggregation-induced emission properties is constructed. Under 808nm laser irradiation, the aggregation-induced emission material exhibits excellent photothermal conversion and generates reactive oxygen species that induce tumor cell death. In near-infrared II fluorescence-photoacoustic dual-modal imaging, photothermal-photodynamic synergistic tumor therapy can effectively kill tumor cells, thereby inhibiting tumor growth or ablating tumors.

Claims

1. A novel near-infrared two-region aggregation-induced emission material, characterized in that, Its general structural formula is as follows: wherein Ar is Dotted lines indicate the attachment site, R1and R2are -t-Bu.

2. A method for preparing a novel near-infrared two-region aggregation-induced emission material according to claim 1, characterized in that, include: Compound II and a reducing agent are added to an acid to obtain a reaction mixture. The reaction mixture is then refluxed under an inert gas atmosphere to obtain an intermediate product. The acid is selected from any one of acetic acid, propionic acid, and n-butyric acid. The structural formula of compound II is: ； The intermediate product and hydrated ninhydrin were added to a mixed organic solvent to obtain the crude product; The crude product was purified and separated to obtain the novel near-infrared II aggregation-induced emission material.

3. The preparation method of the novel near-infrared II aggregation-induced emission material according to claim 2, characterized in that, The reducing agent is selected from any one of H2, Zn, Fe, LiAlH4, KBH4 and NaBH4.

4. The preparation method of the novel near-infrared two-region aggregation-induced emission material according to claim 2, characterized in that, The reflux reaction temperature is 115–125 °C, and the reflux time is 10–14 h.

5. The preparation method of the novel near-infrared II aggregation-induced emission material according to claim 2, characterized in that, The mixed organic solvent is any combination of two solvents selected from dichloromethane, chloroform, tetrahydrofuran, methanol, ethanol, and acetone.

6. The preparation method of novel near-infrared two-region aggregation-induced emission material according to claim 2, characterized in that, The molar ratio of the intermediate product to the aromatic diketone is 1:2.5 to 1:3.

5.

7. The preparation method of novel near-infrared two-region aggregation-induced emission material according to claim 2, characterized in that, The preparation method of compound II includes: Compounds III and IV were added to a second organic solvent to obtain a reaction solution; The palladium catalyst and ligand were added to the reaction solution, and the reaction was carried out under reflux in an inert atmosphere to obtain compound II; the structural formula of compound III is: The structural formula of compound IV is: .

8. The preparation method of novel near-infrared two-region aggregation-induced emission material according to claim 7, characterized in that, The palladium catalyst is selected from one of Pd(PPh3)4, Pd(PPh3)2Cl2, Pd(dppf)Cl2, Pd(OAc)2, Pd2(dba)3, and Pd(dba)2; the ligand is selected from one of 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene, 1,1'-bis(diphenylphosphine)ferrocene, and tris(o-methylphenyl)phosphine.

9. The preparation method of novel near-infrared two-region aggregation-induced emission material according to claim 7, characterized in that, The second organic solvent is selected from one of tetrahydrofuran, N,N-dimethylformamide, 1,4-dioxane, toluene, o-xylene, and mesitylene.

10. The application of a novel near-infrared II aggregation-induced emission material as described in claim 1 in the preparation of a photothermal-photodynamic synergistic ablation therapy for malignant tumors.

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