Quaternary vanadium complexes, methods of making and using the same

Abstract

The application discloses a quaternary vanadium complex, a preparation method thereof and application of the quaternary vanadium complex in preparation of a medicine for treating cancer. The application provides a new quaternary vanadium complex with anticancer activity, which is a quaternary vanadium complex as shown in the following formula I or formula II, and the inhibition rate of the quaternary vanadium complex to A549 cancer cells is more than 60%, and the quaternary vanadium complex has obvious cancer cell inhibition activity.

Description

Technical Field

[0001] This invention belongs to the field of vanadium coordination chemistry, and more specifically, relates to a quaternary vanadium complex with anticancer activity, its preparation method, and its application in the preparation of drugs for treating cancer. Background Technology

[0002] Currently, the incidence of cancer is increasing year by year, and the mortality rate of cancer has risen to the second highest among all diseases, second only to cardiovascular diseases. Therefore, the development of a series of highly effective and low-toxicity anti-tumor drugs has become an urgent task. Scientists have confirmed that Fe-bleomycin is a natural chemotherapeutic agent that targets deoxyribose groups, embedding itself into the DNA of cancer cells and causing single-strand and double-strand breaks. Further research has shown that using VO... 2+ with Fe 2+ Similarity, VO 2+ It can replace Fe 2+ Bleomycin compounds kill cancer cells. In vitro experiments have shown that V-bleomycin compounds exhibit "chemical nuclear activity" under the action of H2O2, generating hydroxyl radicals (·OH), which have a cleaving effect on the DNA of tumor cells. Some pentavalent vanadium and pentavalent peroxide compounds with polypyridine ligands can generate free radicals under ultraviolet light irradiation, thereby cleaving the DNA of tumor cells, and can be used for photodynamic therapy research on cancer. Currently, research on the anticancer mechanism of small molecule drugs mainly focuses on the interaction between molecules and DNA. The interaction between small molecule compounds and DNA can be divided into covalent and non-covalent interactions. Covalent interactions are mainly manifested as intra-chain crosslinking, inter-chain crosslinking, and alkylation of DNA. Covalent forces are often strong, making the interaction between the compound and DNA irreversible. Non-covalent interactions are mainly manifested as intermolecular hydrogen bonding, electrostatic interactions, π-π stacking interactions, and hydrophobic interactions. These forces are relatively weak, making the interaction between the compound and DNA reversible. Typically, small molecule compounds bind to DNA molecules primarily through non-covalent bonds, and can be further classified into insertional binding, groove binding, and electrostatic binding according to different binding modes.

[0003] In recent years, numerous studies have reported newly developed small-molecule vanadium-containing compounds with anticancer activity. For example, the article "Bis(4,7-dimethyl-1,10-phenanthroline)Sulfatooxovanadium(IV) as a Novel Antileukemic Agent with Matrix Metalloproteinase Inhibitory Activity," published in Volume 7 of *Clin. Cancer Res.* in 2001, reported a compound, bis(4,7-dimethyl-1,10-phenanthroline)sulfonyl oxovanadium (METVAN), which exhibited good inhibitory activity against cancer cells such as multiple myeloma. Another example is the article "Terpyridyl oxovanadium(IV) complexes for DNA crosslinking and mito-targeted photocytotoxicity," published in Volume 174 of *J. Inorg. Biochem.* in 2017, which reported two pyridine-based vanadium oxide compounds (structural formulas below) that showed inhibitory activity against cervical cancer cells and breast cancer cells. To this day, research on vanadium-containing compounds with anticancer activity is still in full swing, and therefore, new vanadium-containing compounds will inevitably continue to emerge for people to choose from.

[0004] Summary of the Invention

[0005] Therefore, the inventors dedicated themselves to the research and development of vanadium compounds to complete this invention. One object of this invention is to provide a quaternary vanadium complex with anticancer activity, exhibiting significant inhibitory activity against cancer cells.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned quaternary vanadium complex.

[0007] Another object of the present invention is to provide the use of the above-mentioned quaternary vanadium complex in the preparation of drugs for treating cancer.

[0008] Technical solution

[0009] To achieve the above objectives, according to one aspect of the present invention, a novel quaternary vanadium complex with anticancer activity is provided, which is a quaternary vanadium complex represented by Formula I or Formula II as follows:

[0010]

[0011] In Formulas I and II, R1 is an alkyl, phenyl, furanyl, pyridyl, or thiazolyl group, or an alkyl, phenyl, furanyl, pyridyl, or thiazolyl group substituted with one or more substituents; R2, R3, and R4 are each independently H or alkyl.

[0012] According to another aspect of the present invention, the present invention provides a method for preparing the above-mentioned quaternary vanadium complex, the method comprising: reacting vanadium acetylacetonate (VO(acac)2) with a bidentate nitrogen ligand (L1) and an organic carboxylic acid ligand (L2) in the presence of an organic solvent to obtain the quaternary vanadium complex, wherein the bidentate nitrogen ligand (L1) is 2,2'-bipyridine or alkyl-substituted 2,2'-bipyridine, or o-phenanthroline or alkyl-substituted o-phenanthroline; wherein the organic carboxylic acid ligand (L2) is a monobasic organic carboxylic acid R1COOH, wherein R1 is alkyl, phenyl, furanyl, pyridyl or thiazolyl, or alkyl, phenyl, furanyl, pyridyl or thiazolyl substituted with one or more substituents.

[0013] According to another aspect of the present invention, the present invention provides the use of the above-mentioned quaternary vanadium complex in the preparation of a drug for treating cancer.

[0014] Beneficial effects

[0015] The quaternary vanadium complex of the present invention exhibits an inhibition rate of over 60% against A549 cancer cells at a concentration of 50 μM and an action time of 24 h. Compounds 1 and 3 show the highest inhibition rates against A549 cancer cells, reaching 90%, demonstrating significant cancer cell inhibitory activity. Attached Figure Description

[0016] Figure 1 Here is the crystal structure diagram of compound 1;

[0017] Figure 2 Here is the crystal structure diagram of compound 2;

[0018] Figure 3 Here is the crystal structure diagram of compound 3;

[0019] Figure 4 Here is the crystal structure diagram of compound 4;

[0020] Figure 5 Here is the crystal structure diagram of compound 5;

[0021] Figure 6 The infrared spectrum of compound 1 is shown below.

[0022] Figure 7 The infrared spectrum of compound 2 is shown below.

[0023] Figure 8 The infrared spectrum of compound 3 is shown below.

[0024] Figure 9 The infrared spectrum of compound 4 is shown below.

[0025] Figure 10 The infrared spectrum of compound 5 is shown below.

[0026] Figure 11 The inhibition rate (%) of compounds 1-5 of the present invention and the control sample (vanadium acetylacetonate) on A549 cancer cells. Detailed Implementation

[0027] The following will describe in more detail the quaternary vanadium complex with anticancer activity of the present invention, its preparation method, and its application in the preparation of drugs for treating cancer, in order to aid in understanding the present invention.

[0028] According to one embodiment of the present invention, the present invention provides a novel quaternary vanadium complex with anticancer activity, which is a quaternary vanadium complex represented by Formula I or Formula II as follows:

[0029]

[0030] In Formulas I and II, R1 can be alkyl, phenyl, furanyl, pyridyl or thiazolyl, or alkyl, phenyl, furanyl, pyridyl or thiazolyl substituted with one or more substituents; R2, R3 and R4 can each be H or alkyl independently.

[0031] Preferably, in Formulas I and II, R1 can be an alkyl, phenyl, furanyl, pyridyl, or thiazolyl group, or an alkyl, phenyl, furanyl, pyridyl, or thiazolyl group substituted with one or more substituents, and the substituents can be selected from alkyl, aryl, heteroaryl, nitro, halogen, and substituted alkyl groups. More preferably, the substituents can be selected from C1-C3 alkyl, aryl, heteroaryl, nitro, F, Cl, Br, and substituted C1-C3 alkyl groups. More specifically, as an example, R1 can be phenyl, 3,5-dinitrophenyl, fluorophenyl, formamidothiazolylmethyl, chlorophenoxymethyl, bromopyridyl, furanyl, methyl, or bromophenyl, etc.

[0032] R2, R3 and R4 can each be independently H or alkyl, preferably, they can each be independently H or C1-C3 alkyl, for example, R2, R3 and R4 can each be independently H, methyl or ethyl.

[0033] More specifically, the quaternary vanadium complex may be selected from compounds 1 to 5:

[0034]

[0035]

[0036] According to another embodiment of the present invention, the present invention provides a method for preparing the above-mentioned quaternary vanadium complex, the method comprising: in the presence of an organic solvent, acetylacetonate vanadium oxyacetate (VO(acac)2, molecular formula C... 10 H 14 O5V) reacts with a bidentate nitrogen ligand (L1) and an organic carboxylic acid ligand (L2) to obtain the quaternary vanadium complex, wherein the bidentate nitrogen ligand (L1) can be 2,2'-bipyridine or alkyl-substituted 2,2'-bipyridine, or o-phenanthroline or alkyl-substituted o-phenanthroline; the organic carboxylic acid ligand (L2) can be a monobasic organic carboxylic acid R1COOH, wherein R1 is defined in the same way as R1 in Formula I and Formula II above, that is, it can be alkyl, phenyl, furanyl, pyridinyl or thiazolyl, or alkyl, phenyl, furanyl, pyridinyl or thiazolyl substituted by one or more substituents.

[0037] More specifically, for example, the bidentate nitrogen ligand (L1) can be 2,2'-bipyridine, 4-methyl-2,2'-bipyridine, 6-methyl-2,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine, o-phenanthroline, or 2,9-dimethyl-1,10-o-phenanthroline, etc.; the organic carboxylic acid ligand (L2) can be benzoic acid, 3,5-dinitrobenzoic acid, 3-fluorobenzoic acid, 4-fluorobenzoic acid, 4-chlorophenoxyacetic acid, 6-bromopyridinecarboxylic acid, furanoic acid, or formamidothiazolic acid, etc.

[0038] According to one embodiment of the present invention, in the reaction, the molar ratio of acetylacetone vanadium oxyacetate, bidentate nitrogen ligand (L1), and organic carboxylic acid ligand (L2) can be 1:1:1; the organic solvent can be methanol, ethanol, or acetonitrile, etc.; and the reaction temperature can be from room temperature to reflux temperature.

[0039] In the structural formula of the obtained product, the acetylacetone group acac is bounded to the central V ion by two O atoms in a bidentate chelate coordination, the bidentate nitrogen ligand L1 is bounded to the central V ion by two N atoms in a bidentate chelate coordination, and the organic carboxylic acid ligand L2 is bounded to the central V ion by the O atom of the carboxylate group in a monodentate coordination, forming a quaternary vanadium oxide compound with a six-coordinate octahedral coordination configuration.

[0040] According to another embodiment of the present invention, the quaternary vanadium complex of the present invention has significant cancer cell inhibitory activity, and the present invention provides the application of the above-mentioned quaternary vanadium complex in the preparation of drugs for treating cancer.

[0041] The following examples illustrate in more detail the anticancer quaternary vanadium complex of the present invention, its preparation method, and its application in the preparation of drugs for treating cancer; however, the scope of protection of the present invention is not limited to these examples.

[0042] Example

[0043] Preparation Example 1: Preparation of Compound 1

[0044]

[0045] First, 0.5 mmol of VO(acac)₂, 0.5 mmol of 2,2'-bipyridine, and 0.5 mmol of 3,5-dinitrobenzoic acid were dissolved in 10 ml of methanol. After the reagents were completely dissolved, the 2,2'-bipyridine solution was added to the VO(acac)₂ solution, and the mixture was heated and stirred under reflux at 60°C on a hot plate for 1 hour. Then, the 3,5-dinitrobenzoic acid solution was added, and the reaction was continued for 5 hours. The reaction was then stopped, cooled to room temperature, filtered, and the filtrate was allowed to stand and evaporate before crystals of the corresponding compounds, i.e., the crystals of compound 1, precipitated.

[0046] Preparation Example 2: Preparation of Compound 2

[0047]

[0048] First, 0.5 mmol of VO(acac)₂, 0.5 mmol of o-phenanthroline, and 0.5 mmol of 3,5-dinitrobenzoic acid were dissolved in 10 ml of methanol. After the reagents were completely dissolved, the o-phenanthroline solution was added to the VO(acac)₂ solution, and the mixture was heated and stirred under reflux at 60°C on a hot plate for 1 hour. Then, the 3,5-dinitrobenzoic acid solution was added, and the reaction was continued for 5 hours. The reaction was then stopped, cooled to room temperature, filtered, and the filtrate was allowed to stand and evaporate before crystals of the corresponding compound, i.e., crystals of compound 2, precipitated.

[0049] Preparation Example 3: Preparation of Compound 3

[0050]

[0051] First, 0.1 mmol of VO(acac)2 was dissolved in 6.0 ml of acetonitrile solvent and magnetically stirred until fully dissolved. Then, 0.1 mmol of 2,2'-bipyridine was accurately weighed and added to the above solution. The temperature was maintained at 25°C, and the reaction was allowed to proceed fully to obtain a bright blue solution. 0.1 mmol of 3-fluorobenzoic acid was slowly added while stirring. The reaction was carried out at 25°C for 3 hours with stirring. The solution was filtered through medium-speed filter paper, and after the filtrate was allowed to stand and evaporate, crystals of the corresponding compound, namely the crystals of compound 3, were precipitated.

[0052] Preparation Example 4: Preparation of Compound 4

[0053]

[0054] First, 0.1 mmol of VO(acac)2 was dissolved in 6.0 ml of acetonitrile solvent and magnetically stirred until fully dissolved. Then, 0.1 mmol of o-phenanthroline was accurately weighed and added to the above solution. The temperature was maintained at 25°C, and the reaction was allowed to proceed fully to obtain a brown solution. 0.1 mmol of 4-fluorobenzoic acid was slowly added while stirring. The reaction was carried out at 25°C for 3 hours with stirring. The solution was filtered through medium-speed filter paper. After the filtrate was allowed to stand and evaporate, crystals of the corresponding compound, namely the crystals of compound 4, were precipitated.

[0055] Preparation Example 5: Preparation of Compound 5

[0056]

[0057] First, dissolve 0.5 mmol of VO(acac)₂, 0.5 mmol of o-phenanthroline, and 0.5 mmol of formamide thiazole acetic acid in 10 ml of methanol. After the reagents are completely dissolved, add the o-phenanthroline solution to the VO(acac)₂ solution and heat and stir on a hot plate at 60°C under reflux for 1 hour. Then add the formamide thiazole acetic acid solution and continue the reaction for 5 hours. Stop the reaction, cool to room temperature, filter, and allow the filtrate to stand and evaporate to precipitate crystals of the corresponding compound, i.e., crystals of compound 5.

[0058] Composition and structural characterization:

[0059] The composition and structure of the obtained products were characterized and confirmed by X-ray single-crystal diffraction, infrared spectroscopy, and elemental analysis. The methods used are as follows:

[0060] 1) Infrared spectroscopy measurement:

[0061] Using the KBr tableting method, at wavenumbers of 4000-400 cm⁻¹ -1 Measurements were taken within the specified range using a Bruker EQUINOX 5FT infrared spectrometer.

[0062] 2) Elemental analysis:

[0063] Elemental analysis of C, H, and N in the complex was performed using a Vario EL elemental analyzer.

[0064] 3) X-ray single crystal diffraction:

[0065] Target compounds with smooth, crack-free surfaces and appropriate sizes were selected under a microscope, fixed on a single-crystal diffractometer (XtaLAB Pro), and irradiated with graphite-monochromatized CuKα rays within an appropriate angular range. Crystal diffraction data were collected, and semi-empirical absorption correction was performed using the SADABS program. The positions of non-hydrogen atoms were resolved using a direct method based on F... 2A full-matrix least squares refinement was performed, and all hydrogen atoms were obtained by theoretical hydrogenation. Related calculations were performed on a computer using SHELEXS-97 and Olex2 programs. The crystal structure diagram was drawn using Diamond software.

[0066] Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 These are the crystal structure diagrams of the quaternary vanadium oxide compounds 1, 2, 3, 4, and 5 obtained above. Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 The images are the infrared spectra of the obtained quaternary vanadium oxide compounds 1, 2, 3, 4, and 5, respectively.

[0067] The specific physicochemical properties and crystal data of the quaternary vanadium oxide compounds 1, 2, 3, 4, and 5 are as follows:

[0068] Compound 1: Brown blocky crystals, yield 76%. IR (KBr, cm⁻¹) -1 ): 3438cm -1 (m), 3078cm -1 (w), 1643cm -1 (s), 1565cm -1 (s), 1524cm -1 (s), 1352cm -1 (s), 1282cm -1 (w), 963cm -1 (s), 596cm -1 (w). Among them, 3078cm -1 The peak at 1643 cm⁻¹ is considered to be the stretching vibration peak of the CH single bond. -1 and 1352cm -1 The two peaks represent the asymmetric stretching vibration peak and the symmetric stretching vibration peak of the carboxyl group, respectively, and the difference between the two peaks is greater than 200 cm⁻¹. -1 This indicates that the carboxyl group is coordinated with vanadium in a monodentate manner. The stretching vibration peak of the V=O bond appears at 963 cm⁻¹. -1 The stretching vibration peak of the VO bond appears at 596 cm⁻¹. -1 Elemental analysis (C 22 H 18 N4O9V (%) Theoretical values: C, 49.54; H, 3.38; N, 10.50; Actual values: C, 49.57; H, 3.41; N, 10.48. Molecular formula is C 22 H 18N4O9V; molecular weight M = 533.35; crystal system: monoclinic; space group: P21; cell parameters: a = 7.6513(3), b = 37.8962(12), c = 8.2221(3), β = 100.140(2); volume The residual factors (I≥2σ(I))R1=0.1246, wR2=0.2172.

[0069] Compound 2: Brown blocky crystals, yield 72%. IR (KBr, cm⁻¹) -1 ): 3436cm -1 (s), 3106cm -1 (w), 1649cm -1 (s), 1518cm -1 (s), 1427cm -1 (w), 1321cm -1 (s), 972cm -1 (s), 589cm -1 (w). Among them, 3106cm -1 The peak at 1649 cm⁻¹ indicates the stretching vibration of the CH single bond. -1 and 1321cm -1 The two peaks represent the asymmetric stretching vibration peak and the symmetric stretching vibration peak of the carboxyl group, respectively, and the difference between the two peaks is greater than 200 cm⁻¹. -1 This indicates that the carboxyl group is coordinated with vanadium in a monodentate manner. The vibrational peak of the V=O bond appears at 972 cm⁻¹. -1 At this point, the stretching vibration peak of the VO bond appears at 589 cm⁻¹. -1 Elemental analysis (C 24 H 18 N4O9V (%) Theoretical values: C, 51.72; H, 3.23; N, 10.05; Actual values: C, 51.76; H, 3.26; N, 10.01. Molecular formula is C 24 H 18 N4O9V; molecular weight M = 557.36; crystal system: monoclinic; space group: P21 / c; cell parameters: a = 6.4386(5), b = 21.0539(17), c = 17.8438(14), β = 98.4200(10); volume The residual factors (I≥2σ(I))R1=0.0474, wR2=0.1009.

[0070] Compound 3: Brown blocky crystals, yield 76%. IR (KBr, cm⁻¹) -1 ): 3437cm -1 (s), 1637cm -1 (s), 1561cm -1(s), 1351cm -1 (s), 1313cm -1 (w), 967cm -1 (s), 585cm -1 (w). Among them, 1637cm -1 and 1351cm -1 The peak at that point represents both the asymmetric and symmetric stretching vibrations of the carboxyl group, with a difference greater than 200 cm⁻¹. -1 This indicates that the carboxyl group is coordinated with vanadium in a monodentate manner. The vibrational peak of the V=O bond appears at 967 cm⁻¹. -1 At this point, the stretching vibration peak of the VO bond appears at 585 cm⁻¹. -1 Elemental analysis (C 22 H 19 FN₂O₅ (V,%) Theoretical values: C, 57.27; H, 4.12; N, 6.07; Actual values: C, 57.31; H, 4.16; N, 6.12. Molecular formula: C 22 H 19 FN₂O₅V; molecular weight M = 461.33; crystal system: triclinic; space group: Cell parameters: a = 7.2309(2), b = 8.2282(2), c = 18.2675(4), α = 88.118(2), β = 79.419(2), γ = 76.668(2); volume The residual factor (I≥2σ(I))R1=0.0662wR2=0.1825.

[0071] Compound 4: Brown blocky crystals, yield 74%. IR (KBr, cm⁻¹) -1 ): 3432cm -1 (s), 1641cm -1 (s), 1517cm -1 (s), 1382cm -1 (s), 1333cm -1 (s), 972cm -1 (s), 585cm -1 (w). Among them, 1641cm -1 and 1333cm -1 The two peaks represent the asymmetric stretching vibration peak and the symmetric stretching vibration peak of the carboxyl group, respectively, and the difference between the two peaks is greater than 200 cm⁻¹. -1 This indicates that the carboxyl group is coordinated with vanadium in a monodentate manner. The vibrational peak of the V=O bond appears at 972 cm⁻¹. -1 At this point, the stretching vibration peak of the VO bond appears at 585 cm⁻¹. -1 Elemental analysis (C 24 H 19FN₂O₅ (V,%) Theoretical values: C, 59.39; H, 3.91; N, 5.77; Actual values: C, 59.41; H, 3.95; N, 5.72. Molecular formula: C 24 H 19 FN2O5V; molecular weight M = 485.35; crystal system: monoclinic; space group: P21 / n; cell parameters: a = 11.24570(10), b = 12.8882(2), c = 14.5806(2), β = 92.9950(10); volume The residual factors (I≥2σ(I))R1=0.0423, wR2=0.1096.

[0072] Compound 5: Brown blocky crystals, yield 71%. IR (KBr, cm⁻¹) -1 3450cm -1 (s), 1611cm -1 (s), 1568cm -1 (s), 1372cm -1 (s), 1279cm -1 (s), 927cm -1 (s), 590cm -1 (w). Among them, 1611cm -1 and 1373cm -1 The two peaks represent the asymmetric stretching vibration peak and the symmetric stretching vibration peak of the carboxyl group, respectively, and the difference between the two peaks is greater than 200 cm⁻¹. -1 This indicates that the carboxyl group is coordinated with vanadium in a monodentate manner. The vibrational peak of the V=O bond appears at 927 cm⁻¹. -1 At this point, the stretching vibration peak of the VO bond appears at 590 cm⁻¹. -1 Elemental analysis (C 24 H 24 N4O7 (VS,%) Theoretical values: C, 51.15; H, 4.29; N, 9.94; Actual values: C, 51.03; H, 4.12; N, 10.07. Molecular formula is C 24 H 24 N4O7VS; molecular weight M = 563.47; crystal system: orthorhombic; space group: Pbca; cell parameters: a = 17.7352(4), b = 13.6711(3), c = 20.4238(4); volume The residual factors (I≥2σ(I))R1=0.0630, wR2=0.1165.

[0073] In vitro experiments of compounds 1-5 of the present invention

[0074] The specific experimental procedure is as follows: The MTT assay (MTT = 3-(4,5-dimethyl-2-thiazole)-2,5-diphenyltetrazolium bromide thiazole blue) is used. MTT can penetrate the cell membrane and enter the cell. Dehydrogenases in the mitochondria of living cells can reduce exogenous MTT to water-insoluble purple Formazan crystals, which are deposited in the cells. The amount of Formazan is directly proportional to the cell number and cell viability. This crystal can be dissolved by dimethyl sulfoxide (DMSO), and the absorbance value measured by an enzyme-linked immunosorbent assay (ELISA) analyzer can indirectly reflect the cell number.

[0075] Lung oncology is one of the leading causes of cancer-related deaths worldwide, and researchers have been striving to find ways to diagnose, treat, and prevent this disease. Here, we selected representative human non-small cell lung cancer cells (A549) as our research model. The experimental procedures are as follows:

[0076] (1) Revive frozen A549 cells

[0077] Add 6-7 ml of culture medium to a culture dish; remove the previously frozen cells from the -80℃ freezer; thaw rapidly in a 37℃ water bath; centrifuge at 800 rpm for 3 min; aspirate the supernatant; take 1 ml of culture medium and use a pipette to gently suspend the cells evenly; transfer this cell suspension to a culture dish with added culture medium and incubate in a 37℃ constant temperature cell culture incubator; observe under a microscope every other day and change the culture medium until the cells are passaged.

[0078] (2) Passage the cells to ensure the cell number and condition meet the requirements for MTT assay.

[0079] Aspirate the upper culture medium of the cells prepared for passage, add an appropriate amount of PBS buffer solution, gently shake to rinse the cells, and then discard the solution to remove residual serum and senescent cells. Add 1 ml of trypsin, gently shake to ensure the trypsin infiltrates all cell layers, and after 3 minutes, aspirate the trypsin and place the dish in an incubator for another 3 minutes. Remove the culture dish and add 2 ml of culture medium to stop digestion. Use a pipette to repeatedly pipette and agitate the cell layer on the wall of the culture dish to suspend it and prepare a single-cell suspension. Transfer the suspension to a centrifuge tube, centrifuge at 800 rpm for 3 minutes, and then aspirate the supernatant. Add 6-7 ml of culture medium to a new culture dish. Take 1 ml of culture medium and use a pipette to agitate the cells to suspend them evenly. Transfer this cell suspension to a culture dish with culture medium already added and shake appropriately to disperse the cells. Label the cells and place the dish in an incubator.

[0080] (3) MTT test

[0081] After transferring healthy cells into new dishes according to the passage procedure, the cells were repeatedly pipetted to ensure even dispersion. After mixing, 100 μl of the solution was added to each well of a 96-well plate using a pipette, with the outer 36 wells filled with 100 μl of PBS. The plates were then labeled and incubated for at least 24 hours. The compound and acetylacetonate vanadyl were dissolved in DMSO. 5 μl of each compound was then added to 995 μl of serum-free culture medium to achieve a final concentration of 50 μM. The old culture medium in the well-grown 96-well plates was discarded, and the prepared drug solution was added to each well, with 6 wells per group. The plates were replicated and used as a reference control group. The plates were then incubated for 24 hours. The MTT solution was thawed and mixed with serum-free culture medium at a 1:9 ratio to achieve a final MTT concentration of 0.5 mg / ml. After 24 hours, the 96-well plate was removed, the culture medium in each well was carefully aspirated, and 100 μl of the above MTT solution was added to each well. The plate was then incubated for another hour. After 1 hour, the culture was terminated, the culture medium in each well was aspirated, and 100 μl of dimethyl sulfoxide was added to each well. The solution was repeatedly aspirated to ensure complete dissolution of the crystals. The absorbance was measured using an ELISA reader at wavelengths of 492 nm and 570 nm. Within a certain cell concentration range, the absorbance of the purple Formazan crystals after MTT reduction was directly proportional to the number of viable cells, and this was used to determine the cell viability ratio.

[0082] Figure 11 The results show the inhibition rates (%) of compounds 1-5 and the control sample (vanadium acetylacetonate) against A549 cancer cells. The blank experiment showed that VO(acac)2 had little activity against cells, while compounds 1-5 all exhibited certain cellular activity. At a concentration of 50 μM and an action time of 24 h, the inhibition rate against A549 cancer cells was over 60%, with compounds 1 and 3 showing the highest inhibition rates, reaching 90%. These compounds demonstrate significant inhibitory activity against cancer cells.

[0083] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A quaternary vanadium complex selected from compounds 1 to 5: Compound 1 Compound 2 Compound 3 Compound 4 Compound 5.

2. The quaternary vanadium complex as described in claim 1, characterized in that, The crystal of compound 1 belongs to the monoclinic crystal system; space group is P2 1 Cell parameters: a = 7.6513(3), b = 37.8962(12), c = 8.2221(3), β = 100.140(2); Volume V = 2346.80(15) Å 3 Residual factor ( I≥2σ (I) ) R 1 = 0.1246, wR 2 = 0.2172; The crystal of compound 2 belongs to the monoclinic crystal system; space group is P2 1 / c Cell parameters: a = 6.4386(5) b =21.0539(17), c = 17.8438(14) β = 98.4200(10); Volume V = 2392.8(3) Å 3 Residual factor ( I≥ 2σ (I) ) R 1 = 0.0474, wR 2 = 0.1009; The crystal of compound 3 belongs to the triclinic crystal system; space group is P Cell parameters: a = 7.2309(2), b = 8.2282(2) c = 18.2675(4), = 88.118(2) β = 79.419(2), = 76.668(2); Volume V = 1039.54(5) Å 3 Residual factor ( I≥2σ (I) ) R 1 = 0.0662, wR 2 = 0.1825; The crystal of compound 4 belongs to the monoclinic crystal system; space group is P2 1 / n Cell parameters: a = 11.24570(10), b =12.8882(2) c = 14.5806(2), β = 92.9950(10); Volume V = 2110.38(5) Å 3 Residual factor ( I≥2 σ (I) ) R 1 = 0.0423, wR 2 = 0.1096; The crystal of compound 5 belongs to the orthorhombic crystal system; space group is P bca; Cell parameters: a = 17.7352(4), b =13.6711(3) c = 20.4238(4); Volume V = 4951.95(18) Å 3 Residual factor ( I≥2σ (I) ) R 1 = 0.0630, wR 2 = 0.1165.

3. A method for preparing the quaternary vanadium complex of claim 1, the method comprising: In the presence of an organic solvent, vanadium acetylacetonate (VO(acac)2) reacts with a bidentate nitrogen ligand L1 and an organic carboxylic acid ligand L2 to give the quaternary vanadium complex. Wherein, for compound 1, the bidentate nitrogen ligand L1 is 2,2'-bipyridine, and the organic carboxylic acid ligand L2 is 3,5-dinitrobenzoic acid; For compound 2, the bidentate nitrogen ligand L1 is o-phenanthroline, and the organic carboxylic acid ligand L2 is 3,5-dinitrobenzoic acid; For compound 3, the bidentate nitrogen ligand L1 is 2,2'-bipyridine, and the organic carboxylic acid ligand L2 is 3-fluorobenzoic acid; For compound 4, the bidentate nitrogen ligand L1 is o-phenanthroline, and the organic carboxylic acid ligand L2 is 4-fluorobenzoic acid; For compound 5, the bidentate nitrogen ligand L1 is o-phenanthroline, and the organic carboxylic acid ligand L2 is formamidothiazolic acid.

4. The method as described in claim 3, characterized in that, in In the reaction, the molar ratio of acetylacetone vanadium oxide, bidentate nitrogen ligand L1, and organic carboxylic acid ligand L2 is 1:1:1; the organic solvent is methanol, ethanol, or acetonitrile; and the reaction temperature is from room temperature to reflux temperature.

5. The use of the quaternary vanadium complex of claim 1 in the preparation of a drug for treating cancer.

6. The application as described in claim 5, characterized in that, The cancer in question is lung cancer.

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