Iridium complex sound sensitizers, methods of making and using the same

Abstract

The application discloses an iridium complex sound sensitizer, a preparation method and application thereof, and belongs to the technical field of anti-tumor sound sensitizer drugs. The iridium complex sound sensitizer has two structures, which are named as Ir-1 and Ir-2 respectively, and the preparation methods of the iridium complex sound sensitizer with the two structures are provided. The preparation method is simple, raw materials are easy to obtain, and purification is convenient and easy to operate. Moreover, the prepared iridium complex sound sensitizer has excellent optical physical properties, exhibits good therapeutic effect in mouse breast tumors, effectively inhibits the growth of tumors, and has excellent sonodynamic therapy effect.

Description

Technical Field

[0001] This invention belongs to the field of antitumor acoustic sensitizer technology, specifically relating to iridium complex acoustic sensitizers, their preparation methods, and applications. Background Technology

[0002] Cancer is a leading cause of death, severely impacting people's quality of life. Currently, first-line clinical treatments for cancer remain primarily surgery, chemotherapy, and radiotherapy. However, these methods often lead to serious side effects such as tumor recurrence, multidrug resistance, and damage to the immune system. To date, in efforts to overcome the challenges of insufficient precision and severe side effects faced by traditional medicine, various light-based treatment methods have emerged, including photodynamic therapy (PDT), photothermal therapy (PTT), and microwave therapy; among these, PDT has been developed as a powerful approach to combat tumors minimally invasively in both basic research and clinical practice. However, the limited tissue penetration of light has significantly restricted the development of PDT in vivo, limiting its application in deep tumors.

[0003] Sonodynamic therapy (SDT) is a novel non-invasive cancer treatment derived from photodynamic therapy (PDT), which has attracted widespread attention in basic research and clinical applications in recent years. In SDT, ultrasound (US) is used as the excitation source, inducing the production of highly cytotoxic reactive oxygen species (ROS) by activating a sonosensitizer, thereby leading to cancer cell damage. The underlying mechanism suggests that US irradiation can induce ultrasound cavitation, which further leads to sonoluminescence and pyrolysis, activating the sonosensitizer and resulting in ROS generation. Due to its unique tissue penetration depth (>10 cm), US offers great promise for the eradication of deep tumor tissue.

[0004] Iridium, a member of the platinum group metals, is recognized for its promising antitumor properties, and its complexes are positioned as potential successors to established platinum-based drugs. The excellent stability, ease of synthesis, and tunable photophysical properties of iridium complexes facilitate further structural modification to enhance antitumor activity. In particular, the long excited-state lifetime, good chemical stability, and high phosphorus photoquantum yield of iridium complexes provide a theoretical possibility for the generation of ROS under ultrasound. Therefore, the development of ligand-based iridium complexes with simple structures and easy synthesis will greatly promote the development of SDT (Solidone Therapy). Summary of the Invention

[0005] This invention provides iridium complex acoustic sensitizers, their preparation methods, and applications. The preparation method is simple, the raw materials are readily available, and the prepared iridium complexes can inhibit cancer cell proliferation and kill cancer cells at low concentrations.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Iridium complex acoustic sensitizers, comprising two structures named Ir-1 and Ir-2, have the following chemical structures:

[0008] .

[0009] The preparation method of the above-mentioned iridium complex acoustic sensitizer Ir-1 includes the following steps:

[0010] (1) 2-chloropyridine, benzothiophene-2-boronic acid and catalyst were dissolved in a solvent, the reaction system was kept oxygen-free, and the Suzuki coupling reaction was carried out at 100°C under alkaline conditions for 16 h to obtain 2-(2-pyridyl)benzothiophene;

[0011] (2) Dissolve the 2-(2-pyridyl)benzothiophene and iridium trichloride trihydrate in a solvent, keep the reaction system oxygen-free, and react at 130°C for 24 h to obtain the corresponding dimer;

[0012] (3) Dissolve the dimer and 5-hydroxy-2-pyridinecarboxylic acid in a solvent, keep the reaction system oxygen-free, and carry out a coordination reaction at 60°C under alkaline conditions for 24 h to obtain the target neutral iridium complex sound sensitizer Ir-1;

[0013] In the above steps, the reaction system is preferably carried out under an argon atmosphere in an oxygen-free environment;

[0014] In step (1), the molar ratio of 2-chloropyridine to benzothiophene-2-boric acid is 1:(1~1.2); the molar ratio of 2-chloropyridine to catalyst is 1:(0.04~0.08), and the catalyst is preferably tetra(triphenylphosphine)palladium; the solvent is a mixed solution of water and 1,4-dioxane in a volume ratio of 1:3, and the volume ratio of 2-chloropyridine to water is 0.5 g:10 mL; the alkali used in the alkaline environment is potassium carbonate; and the molar ratio of 2-chloropyridine to potassium carbonate is 1:(5~5.2).

[0015] In step (2), the molar ratio of 2-(2-pyridyl)benzothiophene to iridium trichloride trihydrate is 1:(0.4~0.6); the solvent is a mixed solution of water and 2-ethoxyethanol with a volume ratio of 1:3; the volume ratio of iridium trichloride trihydrate to water is 0.417 g:10 mL;

[0016] In step (3), the molar ratio of the dimer to 5-hydroxy-2-pyridinecarboxylic acid is 1:(2.3~2.8); the solvent is a mixed solution of ethanol and dichloromethane with a volume ratio of 1:3; the volume ratio of the dimer to ethanol is 0.5 g:10 mL; the alkali used in the alkaline environment is potassium carbonate; and the molar ratio of the dimer to potassium carbonate is 1:(10~12).

[0017] The preparation method of the above-mentioned iridium complex acoustic sensitizer Ir-2 includes the following steps:

[0018] (1) 2-Chloroquinoline, benzothiophene-2-boric acid and catalyst were dissolved in a solvent, the reaction system was kept oxygen-free, and the Suzuki coupling reaction was carried out at 100°C under alkaline conditions for 16 h to obtain 2-(1-benzothiophene-2-yl)quinoline;

[0019] (2) Dissolve the 2-(1-benzothiophene-2-yl)quinoline and iridium trichloride trihydrate in a solvent, keep the reaction system oxygen-free, and react at 130°C for 24 h to obtain the corresponding dimer;

[0020] (3) Dissolve the dimer and 5-hydroxy-2-pyridinecarboxylic acid in a mixed solvent, keep the reaction system oxygen-free, and carry out a coordination reaction at 60°C for 24 h to obtain the target neutral iridium complex acoustic sensitizer Ir-2;

[0021] In the above steps, the reaction system is preferably carried out under an argon atmosphere in an oxygen-free environment;

[0022] In step (1), the molar ratio of 2-chloroquinoline to benzothiophene-2-boric acid is 1:(1~1.2); the molar ratio of 2-chloroquinoline to catalyst is 1:(0.04~0.08), and the catalyst is preferably tetra(triphenylphosphine)palladium; the solvent is a mixed solution of water and 1,4-dioxane in a volume ratio of 1:3, and the volume ratio of 2-chloroquinoline to water is 0.5 g:10 mL; the alkali used in the alkaline environment is potassium carbonate; and the molar ratio of 2-chloroquinoline to potassium carbonate is 1:(5~5.2).

[0023] In step (2), the molar ratio of 2-(1-benzothiophene-2-yl)quinoline to iridium trichloride trihydrate is 1:(0.4~0.6); the reaction solvent is a mixed solution of water and 2-ethoxyethanol with a volume ratio of 1:3; the volume ratio of iridium trichloride trihydrate to water is 0.506 g:15 mL;

[0024] In step (3), the molar ratio of the dimer to 5-hydroxy-2-pyridinecarboxylic acid is 1:(2.3~2.8); the reaction solvent is a mixed solution of ethanol and dichloromethane with a volume ratio of 1:3; the volume ratio of the dimer to ethanol is 0.5 g:10 mL; the alkali used in the alkaline environment is potassium carbonate; and the molar ratio of the dimer to potassium carbonate is 1:(10~12).

[0025] All of the above-mentioned iridium complex sonosensitive agents can be used in the preparation of tumor sonodynamic therapy drugs.

[0026] Beneficial effects: This invention provides iridium complex acoustic sensitizers, their preparation methods, and applications, which have the following advantages compared with existing technologies:

[0027] The method for synthesizing the neutral iridium complex prepared by this invention is simple, the raw materials are readily available, and the purification process is convenient and easy to operate.

[0028] The neutral iridium complex prepared by this invention has a triplet excited state energy level that matches well with the excited state energy level of oxygen, and also has a long triplet excited state lifetime and excellent photophysical properties.

[0029] The neutral iridium complex prepared by this invention has high reactive oxygen generation capacity and high sonotoxicity in N,N-dimethylformamide. At low concentrations, it can inhibit cancer cell proliferation and kill cancer cells.

[0030] The neutral iridium complex sonosensitive agent prepared in this invention showed good therapeutic effects in mouse mammary tumors, effectively inhibiting tumor growth and exhibiting excellent sonodynamic therapeutic effects. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the preparation route of the iridium complex Ir-1 in this embodiment of the invention;

[0032] Figure 2 This is a flowchart illustrating the preparation route of the iridium complex Ir-2 in this embodiment of the invention;

[0033] Figure 3 The degradation test results of DPBF by neutral iridium complexes Ir-1 and Ir-2 and reference ruthenium terpyridine under ultrasonic treatment are shown.

[0034] Figure 4 Figure 1 shows the cytotoxicity test results of neutral iridium complexes Ir-1 and Ir-2 on 4T1 cells.

[0035] Figure 5 This is a graph showing the inhibition of mouse breast cancer tumors by the neutral iridium complex Ir-1. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments: Example 1

[0037] The preparation method of iridium complex Ir-1 specifically includes the following steps:

[0038] 2-Chloropyridine (0.5 g, 4.404 mmol), benzothiophene-2-boronic acid (0.862 g, 4.844 mmol), tetrakis(triphenylphosphine)palladium (0.407 g, 0.352 mmol), and potassium carbonate (3.043 g, 22.02 mmol) were added to a 100 mL two-necked flask. 1,4-Dioxane (30 mL) and water (10 mL) were added, and the mixture was kept under argon protection at 100 °C for 16 h. After the reaction was complete and cooled to room temperature, the mixture was extracted with ethyl acetate and saturated brine, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was purified by column chromatography using [eluent name missing]. V (Petroleum ether): V (Ethyl acetate) = 15:1, yielding a white solid 2-(2-pyridyl)benzothiophene;

[0039] Iridium trichloride trihydrate (0.417 g, 1.184 mmol) and 2-(2-pyridyl)benzothiophene (0.5 g, 2.367 mmol) were added to a 100 mL round-bottom flask, along with 30 mL of 2-ethoxyethanol and 10 mL of water. The reaction was carried out under an argon atmosphere at 130 °C for 24 h. After the reaction mixture was completely cooled to room temperature, it was slowly poured into a beaker containing 100 mL of water. After stirring for 30 minutes, the mixture was filtered, and the residue was dried to obtain a red solid, which was the dimer.

[0040] The dimer (0.5 g, 0.386 mmol), 5-hydroxy-2-pyridinecarboxylic acid (0.134 g, 0.965 mmol), and potassium carbonate (0.587 g, 4.246 mmol) were added to a 100 mL round-bottom flask, followed by the addition of dichloromethane (30 mL) and ethanol (10 mL). The mixture was reacted under an argon atmosphere at 60 °C for 24 h. After the reaction was complete, the mixture was filtered, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was then purified by column chromatography using [eluent name missing]. V (Dichloromethane): V (Methanol) = 20:1, yielding a red solid, which is the neutral iridium complex Ir-1.

[0041] Ir-1: 1 H NMR (400 MHz, DMSO- d 6) δ 11.13 (s, 1H), 8.58 (d, J = 5.8 Hz,1H), 8.02 – 7.83 (m, 7H), 7.63 (d, J = 5.8 Hz, 1H), 7.41 (dd, J= 8.7, 2.6 Hz, 1H), 7.34 (ddd, J = 7.4, 5.8, 1.5 Hz, 1H), 7.24 – 7.10 (m, 4H), 6.86 (dt, J =26.6, 7.6 Hz, 2H), 6.13 (d, J = 8.1 Hz, 1H), 5.91 (d, J = 8.1 Hz, 1H). Example 2

[0042] The preparation method of iridium complex Ir-2 specifically includes the following steps:

[0043] 2-Chloroquinoline (0.5 g, 3.056 mmol), benzothiophene-2-boronic acid (0.598 g, 3.362 mmol), tetrakis(triphenylphosphine)palladium (0.282 g, 0.244 mmol), and potassium carbonate (2.112 g, 15.28 mmol) were added to a 100 mL round-bottom flask. 1,4-Dioxane (30 mL) and water (10 mL) were added, and the mixture was reacted under argon protection at 100 °C for 16 h. After the reaction was complete and cooled to room temperature, the reaction solution was extracted with ethyl acetate and saturated brine, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was purified by column chromatography using [eluent name missing]. V (Petroleum ether): V (Ethyl acetate) = 15:1, yielding a white solid 2-(1-benzothiophen-2-yl)quinoline;

[0044] Iridium trichloride trihydrate (0.506 g, 1.435 mmol) and 2-(1-benzothiophene-2-yl)quinoline (0.75 g, 2.870 mmol) were added to a 100 mL round-bottom flask, along with 45 mL of 2-ethoxyethanol and 15 mL of water. The reaction was carried out under an argon atmosphere at 130 °C for 24 h. After the reaction mixture had completely cooled to room temperature, it was slowly poured into a beaker containing 100 mL of water. After stirring for 30 minutes, the mixture was filtered, and the residue was dried to obtain a red solid, which was the dimer.

[0045] The dimer (0.5 g, 0.334 mmol), 5-hydroxy-2-pyridinecarboxylic acid (0.116 g, 0.835 mmol), and potassium carbonate (0.508 g, 3.674 mmol) were added to a 100 mL round-bottom flask, followed by the addition of dichloromethane (30 mL) and ethanol (10 mL). The mixture was reacted under an argon atmosphere at 60 °C for 24 h. After the reaction was complete, the mixture was filtered, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was then purified by column chromatography using [eluent name missing]. V (Dichloromethane): V (Methanol) = 20:1, yielding a red solid, which is a neutral iridium complex Ir-2.

[0046] Ir-2: 1 H NMR (400 MHz, DMSO- d 6) δ 11.13 (s, 1H), 8.59 (d, J = 8.7 Hz, 1H), 8.53 (d, J = 8.7 Hz, 1H), 8.36 (d, J = 8.7 Hz, 1H), 8.18 (d, J = 8.6 Hz, 1H), 8.09 (d, J = 8.6 Hz, 1H), 8.03 – 7.91 (m, 3H), 7.87 (d, J = 8.0 Hz, 1H), 7.62 (d, J = 2.6 Hz, 1H), 7.38 (tdd, J = 16.4, 8.0, 1.5 Hz, 4H), 7.23 – 7.12 (m, 2H), 7.05 (ddd, J = 8.2, 7.1, 1.3 Hz, 1H), 7.00 – 6.89 (m, 2H), 6.69 (ddd, J = 8.2,7.0, 1.1 Hz, 1H), 6.55 (ddd, J = 8.2, 7.0, 1.2 Hz, 1H), 6.45 (d, J = 8.1 Hz, 1H), 5.89 (d, J = 8.1 Hz, 1H).

[0047] Test 1

[0048] In N,N-dimethylformamide, using 1,3-diphenylisobenzofuran as a ROS indicator and ruthenium terpyridine as a standard, the ROS generation of neutral iridium complexes Ir-1 and Ir-2 under ultrasonication was evaluated. The specific experimental steps are as follows:

[0049] 1,3-Diphenylisobenzofuran (1x10⁻⁶) was prepared under dark conditions. -2 M) and containing neutral iridium complexes Ir-1, Ir-2 (1x10) -5 A mixed solution of M) was then sonicated (2.5 W·cm). -2 Irradiation was performed, and the maximum absorbance was measured every 1 minute at 410 nm. The degradation effects of neutral iridium complexes Ir-1 and Ir-2 and the reference terpyridine ruthenium on 1,3-diphenylisobenzofuran under ultrasonic irradiation were evaluated. Figure 3 As shown, the oxidation rate of neutral iridium complexes Ir-1 and Ir-2 was calculated to be 0.04081 min. -1 0.05358 min -1 The oxidation rate of the reference compound, ruthenium tripyridine, under ultrasonic irradiation was higher than that of ruthenium tripyridine (0.03493 min). −1 This indicates that it has excellent reactive oxygen species generation capacity.

[0050] Test 2

[0051] The sonotoxicity of neutral iridium complexes Ir-1 and Ir-2 to 4T1 cancer cells under both ultrasound-treated and non-ultrasound-treated conditions was detected by the CCK-8 assay. The specific experimental steps are as follows:

[0052] 4T1 cancer cells were seeded into well plates, and culture medium containing different concentrations of neutral iridium complexes Ir-1 and Ir-2 was added. After incubation with the neutral iridium complexes Ir-1 and Ir-2 for 24 h, the cells were sonicated (0.7 W·cm). -2 Cells were irradiated; the control group was not irradiated. After incubation for 3 or 5 minutes, CCK-8 was added and incubated for 1.5 hours. The absorbance of the absorption peak at 450 nm in each well was measured by microplate reader, and the survival rate of cancer cells was calculated.

[0053] The CCK-8 test results are as follows: Figure 4 As shown, in ultrasound (0.7W·cm) -2Under the conditions of ultrasound treatment, as the concentrations (0-50 μM) of neutral iridium complexes Ir-1 and Ir-2 increased, when the concentration reached 50 μM, the cell survival rates of complex Ir-1 at 3 min and 5 min were 61.8% and 17.1%, respectively, and the cell survival rates of complex Ir-2 at 3 min and 5 min were 53.2% and 15.8%, respectively. This indicates that when the concentration reached 50 μM, the cell survival rate decreased more significantly with increasing ultrasound time, especially after 5 min of ultrasound treatment. This suggests that the neutral iridium complexes Ir-1 and Ir-2 of the present invention have high sonotoxicity.

[0054] Test 3

[0055] The efficacy of the neutral iridium complex Ir-1 in treating breast cancer was evaluated in mice. Twelve mice were randomly divided into four groups. The grouping and specific experimental procedures are as follows:

[0056] (1) Inject phosphate buffer solution without any treatment; (2) Inject phosphate buffer solution and use ultrasound irradiation; (3) Inject neutral iridium complex Ir-1 (2.66 mM) without ultrasound; (4) Inject neutral iridium complex Ir-1 (2.66 mM) and use ultrasound for treatment.

[0057] Fifteen days after treatment, all mice were sacrificed, and tumors and major organ tissues were collected to evaluate the treatment effect. The resulting tumor inhibition graph is shown below. Figure 5 As shown, the tumors in groups 1, 2, and 3 all grew rapidly, while the tumor growth in group 4 was significantly inhibited. The neutral iridium complex Ir-1 of the present invention has excellent sonodynamic therapeutic effects.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of an iridium complex photosensitizer characterized in that, The iridium complex sensitizer is used for preparing a sonodynamic tumor treatment drug; the iridium complex sensitizer comprises two structures, which are respectively named as Ir-1 and Ir-2, and the chemical structures are as follows: 。 2. Use of an iridium complex photosensitiser according to claim 1, characterised in that, The preparation method of the iridium complex sensitizer comprises the following steps: (1) corresponding raw materials, benzothiophene-2-boric acid and a catalyst are dissolved in a solvent, the reaction system is kept oxygen-free, a Suzuki coupling reaction occurs in an alkaline environment; when the target iridium complex sensitizer is Ir-1, the corresponding raw material is 2-chloropyridine, and 2-(2-pyridyl) benzothiophene is obtained after the Suzuki coupling reaction; when the target iridium complex sensitizer is Ir-2, the corresponding raw material is 2-chloroquinoline, and 2-(1-benzothiophene-2-yl) quinoline is obtained after the Suzuki coupling reaction; (2) the product obtained in step (1) is dissolved in a solvent with iridium trichloride trihydrate, the reaction system is kept oxygen-free, and the reaction is carried out at 130°C for 24 h to obtain the corresponding dimer; when the target iridium complex sonosensitizer is Ir-1, the corresponding dimer is ; when the target iridium complex sonosensitizer is Ir-2, the corresponding dimer is . (3) the corresponding dimer and 5-hydroxy-2-pyridine carboxylic acid are dissolved in a solvent, the reaction system is kept oxygen-free, a coordination reaction occurs, and the target iridium complex sensitizer is obtained.

3. Use of an iridium complex photosensitiser according to claim 2, characterised in that, In step (1), the molar ratio of the corresponding raw material to benzothiophene-2-boric acid is 1: (1-1.2); the molar ratio of the corresponding raw material to the catalyst is 1: (0.04-0.08); the alkali used in the alkaline environment is potassium carbonate, and the molar ratio of the corresponding raw material to potassium carbonate is 1: (5-5.2); the solvent is a mixed solution of water and 1, 4-dioxane in a volume ratio of 1:3, and the usage ratio of the corresponding raw material to water is 0.5 g: 10 mL.

4. Use of an iridium complex photosensitiser according to claim 2, characterised in that, The catalyst is tetrakis (triphenylphosphine) palladium.

5. Use of an iridium complex photosensitiser according to claim 2, characterised in that, In step (2), the molar ratio of the product obtained in step (1) to iridium trichloride trihydrate is 1: (0.4-0.6).

6. Use of an iridium complex photosensitiser according to claim 2, characterised in that, In step (2), the solvent is a mixed solution of water and 2-ethoxyethanol in a volume ratio of 1:3; when the product is Ir-1, the usage ratio of iridium trichloride trihydrate to water is 0.417 g: 10 mL; when the product is Ir-2, the usage ratio of iridium trichloride trihydrate to water is 0.506 g: 15 mL.

7. Use of an iridium complex photosensitiser according to claim 2, characterised in that, In step (3), the molar ratio of the dimer to 5-hydroxy-2-pyridine carboxylic acid is 1: (2.3-2.8); the reaction solvent is a mixed solution of ethanol and dichloromethane in a volume ratio of 1:3; and the usage ratio of the dimer to ethanol is 0.5 g: 10 mL.

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