A pillar[5]arene-based fluorescent material and its application in kidney-targeting imaging agents

Abstract

The application discloses a pillar[5]arene-based fluorescent material and application thereof in kidney-targeting developing agents. The fluorescent material is prepared by the following steps: 4-methylpyridine and 4-dimethylaminobenzaldehyde are used as raw materials, and DMAS is obtained through reaction and crystallization; then, 1,4-bis(2-hydroxyethoxy)benzene, triphenylphosphine, carbon tetrabromide and polyformaldehyde are used as raw materials to prepare an intermediate, and the intermediate, DMAS and pyridine are used as raw materials to carry out reflux reaction in the participation of CH3CN, and finally, the pillar[5]arene-based fluorescent material is obtained. The pillar[5]arene-based fluorescent material is a novel fluorescent compound, can be used for kidney-targeting aggregation and imaging, and has the characteristics of low cytotoxicity, good biocompatibility, good stability, high sensitivity, low cost and easy use.

Description

TECHNICAL FIELD

[0001] The present application relates to a fluorescent material and its application, in particular to a pillar[5]arene-based fluorescent material and its application in kidney-targeted imaging agents. BACKGROUND

[0002] The kidney is a high-perfusion organ that removes metabolic waste from the blood in urine and plays a key role in maintaining fluid and electrolyte homeostasis. Due to its high metabolic activity, the kidney is also susceptible to injury. Studies have reported that the prevalence of chronic kidney disease (CKD) in the population is 10%, and more than 50% of the population is at high risk of the disease, which is a global public health problem and a major burden to society.

[0003] In fact, glomerular disease is the main cause of CKD, and hypertensive nephropathy and diabetic nephropathy are more common in adults, while immune and genetic glomerular diseases are mainly seen in children. Despite the variety of causes, the earliest and most significant pathological structural changes in these diseases are damage to the glomerular filtration barrier (GFB), which is composed of three layers: glomerular endothelial cells, glomerular basement membrane (GBM), and podocytes. Therefore, early and accurate assessment of kidney GFB function is crucial for early implementation of kidney-protective interventions to avoid progression to CKD. The charge barrier and mechanical barrier in the GFB are also closely related and influence each other in structure and function. Kidney biopsy is the gold standard for diagnosing the pathological type of kidney disease, however, it is invasive and has the risk of causing organ damage. Traditionally, other non-invasive medical imaging techniques, such as radionuclide imaging (RNI), magnetic resonance imaging (MRI), and X-ray computed tomography (CT), have been used to assess kidney function. However, these procedures are either costly or have radiation, and there is a risk of nephrotoxicity caused by contrast agents. At the same time, the charge barrier function of the glomerulus cannot be assessed by the above methods. In fact, the loss of anionic charge on the glomerulus occurs early in the morphological changes of the glomerulus and the appearance of proteinuria, indicating that charge barrier damage is the earliest change in renal dysfunction. Therefore, early identification of the status of the glomerular charge barrier is particularly critical for early identification of kidney disease.

[0004] Fluorescence imaging (FLI) has high sensitivity and low cost, thus has unique advantages in imaging. With the advancement of in vivo imaging technology, there is an increasing demand for non-invasive imaging. In addition, real-time and specific targeted fluorescence imaging are also the focus of research. The glomerular charge barrier is composed of a variety of negatively charged biological macromolecules, so the surface of the glomerulus is usually negatively charged. Based on this characteristic, designing positively charged fluorescent materials is expected to perform well in kidney-targeted imaging and early damage detection.

[0005] Pillararenes are a new class of macrocyclic compounds, which are composed of methylene-bridged dialkoxybenzene units. Pillararenes have the characteristics of simple synthesis and easy functionalization, and can be added with functional groups on their framework to meet the needs of various applications. At the same time, a large number of studies have shown that pillararenes have low cytotoxicity and good biocompatibility, which enables pillararenes to be used for imaging. Li and colleagues synthesized pillararene functionalized graphene as a fluorescent probe for paraquat in cells and mice in vivo, while the groups of Wang and Hu each constructed water-soluble pillararenes as potential fluorescent materials for cancer imaging. It can be seen that the synthesis and application of fluorescent materials based on the structure of pillararenes have made some progress, but still have great potential and value after modification. However, fluorescent materials based on the structure of pillararenes for kidney-targeted aggregation imaging have not been reported. SUMMARY

[0006] The purpose of the present application is to provide a pillar[5]arene-based fluorescent material and its application in kidney-targeted imaging agents. The pillar[5]arene-based fluorescent material of the present application belongs to a new type of fluorescent compound, which can be used for kidney-targeted aggregation and imaging, and has the characteristics of low cytotoxicity, good biocompatibility with biological tissues, good stability, high sensitivity, low cost and easy application, etc.

[0007] The technical solution of the present application is a pillar[5]arene-based fluorescent material, which has a chemical structural formula as shown in the accompanying Figure 1 The molecular weight of the pillar[5]arene-based fluorescent material is 2.6 kDa.

[0008] The preparation process of the aforementioned pillar[5]arene-based fluorescent material includes the following steps:

[0009] (1) Synthesis of DMAS

[0010] a. Mix 4-methylpyridine, potassium tert-butoxide and dry DMF, heat the mixture to 55-65℃ and react for 1-3h to obtain product A;

[0011] b. Add 4-dimethylaminobenzaldehyde to product A and raise the temperature to 75-85℃ and react for 6-10 hours to obtain product B;

[0012] c. Cool product B to 20-30℃ and pour into normal temperature water to obtain yellow-green precipitate, filter out the yellow-green precipitate and wash with a mixture of ethanol / cold water, then recrystallize from ethanol, and finally dry the crystals to obtain DMAS;

[0013] (2) Synthesis of pillar[5]arene-based fluorescent material

[0014] 1) Synthesis of compound 1

[0015] a. Dissolve 1,4-bis(2-hydroxyethoxy)benzene and triphenylphosphine in dry acetonitrile to obtain product C;

[0016] b. Carbon tetrabromide was slowly added to C while stirring at 0°C, and after the addition was complete, the mixture was heated to 20-30°C to obtain D;

[0017] c. D was stirred for an additional 3-5 hours under N2, then cold water was added to obtain a white precipitate, which was filtered off and washed with a mixture of methanol / water, then recrystallized from methanol, and finally the crystals were dried to obtain compound 1;

[0018] 2) Synthesis of compound 2

[0019] a. Compound 1 was dissolved in 1,2-dichloroethane to obtain E;

[0020] b. To E, under N2, was added paraformaldehyde, then to the solution was added boron trifluoride etherate, and stirred at 20-30°C for 2-4 hours to obtain F;

[0021] c. The solvent was removed from F using a rotary evaporator, then the white solid obtained was purified by column chromatography on silica gel using petroleum ether / dichloromethane as eluent to obtain compound 2;

[0022] 3) Synthesis of pillar[5]arene-based fluorescent material

[0023] Compound 2, DMAS and dry CH3CN were mixed and refluxed for 3-7 hours, then pyridine was added to the solution and refluxed for 10-20 hours, and finally the solution was removed by rotary evaporator and the precipitate was washed with diethyl ether, and the precipitate was dried to obtain the pillar[5]arene-based fluorescent material.

[0024] The aforementioned pillar[5]arene-based fluorescent material, the preparation process of which comprises the following steps:

[0025] (1) Synthesis of DMAS

[0026] a. 1.33 ml, 13.4 mmol of 4-methylpyridine, 225.5 mg, 2.01 mmol of potassium tert-butoxide and 15 ml of dry DMF were mixed, and the mixture was heated to 55-65°C for 1-3 hours to obtain A;

[0027] b. To A was added 200.0 mg, 1.34 mmol of 4-dimethylaminobenzaldehyde and the temperature was raised to 75-85°C for 6-10 hours to obtain B;

[0028] c. B was cooled to 20-30°C and poured into water to obtain a yellow-green precipitate, which was filtered off and washed with a mixture of ethanol / cold water, then recrystallized from ethanol, and finally the crystals were dried to obtain DMAS;

[0029] (2) Synthesis of pillar[5]arene-based fluorescent material

[0030] 1) Synthesis of compound 1

[0031] a. Dissolve 10.0 g, 50.4 mmol of 1,4-bis(2-hydroxyethoxy)benzene and 31.5 g, 1205 mmol of triphenylphosphine in 300 mL of dry acetonitrile to obtain C-product;

[0032] b. Slowly add 39.8 g, 120 mmol of carbon tetrabromide to C-product while stirring, and after the addition is complete, heat the mixture to 20-30°C to obtain D-product;

[0033] c. Stir D-product under N2for an additional 3-5 hours, then add 200 mL of cold water to obtain white precipitate, filter out the white precipitate, wash with a mixture of methanol / water, then recrystallize from methanol, and finally dry the crystals to obtain compound 1;

[0034] 2) Synthesis of compound 2

[0035] a. Dissolve 3.37 g, 11.5 mmol of compound 1 in 200 ml of 1,2-dichloroethane to obtain E-product;

[0036] b. Add 0.349 g, 11.5 mmol of paraformaldehyde to E-product under N2, then add 1.63 g, 11.5 mmol of boron trifluoride etherate to the solution, and stir at 20-30°C for 2-4 h to obtain F-product;

[0037] c. Remove the solvent from F-product using a rotary evaporator, then purify the resulting white solid, i.e., compound 2, by column chromatography on silica gel using 1:2 v / v petroleum ether / dichloromethane as the eluent;

[0038] 3) Synthesis of pillar[5]arene-based fluorescent material

[0039] Mix 1 g, 0.595 mmol of compound 2, 133.5 mg, 0.59 mmol of DMAS, and 60 ml of dry CH3CN and reflux for 3-7 hours, then add 0.48 ml, 5.95 mmol of pyridine to the solution and reflux for 10-20 h, and finally remove the solution using a rotary evaporator and wash the precipitate with ether, and dry the precipitate to obtain pillar[5]arene-based fluorescent material.

[0040] The aforementioned pillar[5]arene-based fluorescent material, when synthesizing DMAS, the reaction temperature in step a is 60°C, and the reaction time is 2 h; the reaction time in step b is 80°C, and the reaction is 8 h; and step c is to cool B-product to 25°C and then pour it into 150 ml of water.

[0041] The column [5] arene-based fluorescent material of the preceding, wherein the volume ratio of ethanol to water in the mixture of ethanol / cold water in step c is 1:1 when synthesizing DMAS.

[0042] The column [5] arene-based fluorescent material of the preceding, wherein the carbon tetrabromide is added at 0℃ in step b when synthesizing compound 1, and the temperature of the mixture is heated to 25℃ after the addition is completed.

[0043] The column [5] arene-based fluorescent material of the preceding, wherein the volume ratio of methanol to water in the mixture of methanol / water in step c is 60:40 when synthesizing compound 1.

[0044] The column [5] arene-based fluorescent material of the preceding, wherein the refluxing time is 5h in step 3) for the first time, and the refluxing is continued for 12h after adding pyridine.

[0045] The column [5] arene-based fluorescent material of the preceding is applied to a kidney-targeting imaging agent.

[0046] A kidney-targeting imaging agent containing the column [5] arene-based fluorescent material of the preceding.

[0047] Advantages of the present application

[0048] The column [5] arene-based fluorescent material of the present application is a cationic water-soluble column [5] arene with ten positive charges, which can be used for kidney-targeting imaging.

[0049] The column [5] arene-based fluorescent material of the present application has good biological tissue safety, good water solubility (up to 10 -2 mol / L), high stability and good fluorescence properties, and can be used as a preferred biomedical material for kidney-targeting imaging.

[0050] Blood urea nitrogen (BUN) and serum creatinine (sCr) are commonly used indicators for clinical evaluation of kidney function. However, these indicators are not only easily disturbed by various factors, but also cannot accurately assess the function of each kidney. The column [5] arene-based fluorescent material enters the body, and according to the fluorescent signal released by each kidney, we can track and quantify the corresponding signal intensity in order to accurately identify the specific function of each kidney. In order to target the early detection of the charge barrier function in the kidney, based on the negative charge of the glomerular charge barrier and the property of attracting positive and negative charges, the column [5] arene-based fluorescent material with 10 positive charges can well achieve this requirement. In fact, after injecting the fluorescent material into the tail vein of a living mouse, the material almost only accumulates in the kidney, and no obvious accumulation is found in other high-perfusion organs such as liver, heart and lung. At the same time, we have proved in detail the low biological toxicity of the column [5] arene-based fluorescent material in the in vivo imaging application.

[0051] The present application provides a fluorescent biomaterial for kidney-specific imaging, and will help to lay a theoretical foundation for the application of column[n]arene-based fluorescent biomaterials in targeted imaging research for early identification of kidney diseases.

[0052] 1. Physicochemical property research

[0053] Molecular modeling was used to provide structural information of the column[5]arene-based fluorescent material (hereinafter referred to as P5DMP) by density functional theory (DFT) calculation at the B3LYP / 6-311g(d,p) level. As shown in Figure 2 , the electron density of the lowest unoccupied molecular orbital (LUMO, -2.73 eV) is mainly concentrated on the electron-deficient pyridine unit, while the highest occupied molecular orbital (HOMO, -5.54 eV) is distributed in the N,N-dimethylstyrene part of P5DMP, indicating that the direction of intramolecular charge transfer is from N,N-dimethylstyrene to the pyridine unit.

[0054] Subsequently, in order to explore the possibility of the compound in biological imaging, we studied some photochemical properties of P5DMP. As shown in Figure 3 , the maximum absorption peak of P5DMP is located at ≈480 nm, and the emission peak is located at ≈614 nm. The fluorescence intensity of P5DMP increases with the increase of concentration, and the emission intensity reaches the highest at a concentration of 20 μM, accompanied by a slight red shift phenomenon, which is conducive to imaging at the target site.

[0055] Charge is a key issue for glomerular accumulation, because high positive charge (>15 mV) can cause kidney damage. Therefore, we detected the zeta potential of P5DMP, and the result was 14.9 mV, which is within the allowable range reported in the study and will not cause damage to the kidney Figure 4 ).

[0056] The morphology of P5DMP in aqueous solution was observed by scanning electron microscopy. As shown in Figure 5 , P5DMP can spontaneously assemble into sheet-like structures and tightly stack together after dissolving in aqueous solution.

[0057] 2. Non-toxicity study

[0058] Human podocyte cells (HPCs), human mesangial cells (HMCs) and renal tubular epithelial cells (HK2) were cultured in vitro, and P5DMP with a concentration of 25 um / ml was added for continuous culture for 0.5 h, 1 h, 2 h, 3 h and 4 h, respectively. CCK8 experiment showed that the activity of the three types of kidney intrinsic cells remained above 80% within 4 h of in vitro culture Figure 6 .

[0059] Meanwhile, female Bal / bc mice were injected with P5DMP 2.5 mg / kg via tail vein. The body weight of the mice decreased on the first day, and there was no significant difference between the experimental group and the normal saline control group for the following 13 days. Figure 7 HE staining showed that there was no significant damage to the important organs of the kidney, liver, heart and lung. Figure 8 Blood biochemical indicators showed that the P5DMP injection group was within the normal range (Table 1).

[0060] Table 1. Biochemical index of Bal / bc mice after injection of P5DMP in vivo

[0061]

[0062] Further, focusing on the evaluation of kidney function, immunofluorescence staining of glomerular specific marker Synaptopodin and tubular specific marker Megalin showed no change. Figure 9 At the same time, proteinuria, an indicator of kidney damage, only appeared on the first day after P5DMP injection, and there was no proteinuria for the following 13 days, indicating that it was a transient proteinuria. Figure 10

[0063] The above results confirm that P5DMP is biologically non-toxic and is the basis for exploring its use as an in vivo imaging material.

[0064] 3. In vitro kidney intrinsic cell line imaging

[0065] Human podocytes (HPCs), human mesangial cells (HMCs) and renal tubular epithelial cells (HK2) were cultured in vitro, and P5DMP at a concentration of 25 um / ml was added for continuous culture for 1 h, 2 h and 3 h. Flow cytometry was used to detect the absorption fluorescence intensity of P5DMP in the three different types of cells. The results showed that the fluorescence intensity of P5DMP in the three types of cells increased significantly with the extension of culture time. The fluorescence intensity of P5DMP was significantly higher than that of the blank control group after 1 h of in vitro culture. Figure 11 At the same time, the results showed that the absorption intensity of P5DMP was highest in podocytes, followed by mesangial cells, and lowest in tubular cells, indicating that the imaging material had cell-specific absorption intensity.

[0066] At the same time, confocal microscopy was used to show the absorption and distribution characteristics of P5DMP in the three types of cells. The results showed that the absorption intensity characteristics were consistent with the flow cytometry results, and further showed that P5DMP was mainly distributed in the cytoplasm and nucleus of HPCs and HMCs, while it was mainly distributed in the perinuclear region of HK2 cells. Figure 12

[0067] ​​The above results suggest that P5DMP has different distribution patterns and absorption intensities in different renal intrinsic cell types, and may be used as a specific imaging material for different cells in renal tissue for cell tracing.

[0068] 4. In vivo kidney targeted imaging

[0069] Based on the characteristics of the glomerulus, we designed the imaging substance P5DMP with 10 positive charges, which can be targeted to the glomerular filtration barrier for specific aggregation and imaging. In vivo experiments showed that two days after the tail vein injection of P5DMP, the substance was indeed only aggregated and visualized in the kidneys ( Figure 13 ), while there was almost no accumulation in other high perfusion organs such as lung, heart and liver ( Figure 14 In addition, the results showed that P5DMP significantly accumulated in the glomeruli and was taken up by negatively charged podocytes, mesangial cells, or endothelial cells, but rarely in tubular cells. This result is consistent with the in vitro cell experiments, confirming that P5DMP is an excellent targeted imaging agent for the kidneys, especially the glomeruli. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Attachment Figure 1 is the chemical structural formula of the pillar[5]arene-based fluorescent material (P5DMP) of the present invention;

[0071] Attachment Figure 2 Schematic diagram of the frontier molecular orbitals (LUMO and HOMO) of P5DMP;

[0072] Attachment Figure 3 is the UV absorption and fluorescence emission of P5DMP in aqueous solution;

[0073] Attachment Figure 4 is the zeta potential of P5DMP;

[0074] Attachment Figure 5 is the SEM image of P5DMP;

[0075] Attachment Figure 6 Figure 2 shows the cell viability of HK2, HMC, and HPCs cultured with P5DMP in vitro;

[0076] Attachment Figure 7 Body weight of Bal / bc mice for 14 consecutive days after injection of P5DMP;

[0077] Attachment Figure 8 HE staining of kidney, liver, heart and lung after injection of P5DMP in Bal / bc mice;

[0078] Attachment Figure 9 This is the proteinuria status of Bal / bc mice after injection of P5DMP for 14 consecutive days;

[0079] Attachment Figure 10 The expression of Synaptopodin, a classic glomerular marker, and Megalin, a classic tubular marker, were measured in Bal / bc mice injected with P5DMP.

[0080] Attachment Figure 11 Flow cytometry was used to detect the fluorescence intensity of HK2, HMC and HPCs cells cultured with P5DMP;

[0081] Attachment Figure 12 Confocal microscopy was used to detect the fluorescence intensity of HMC and HPCs cells cultured with P5DMP.

[0082] Attachment Figure 13 The accumulation of substances in the kidneys and local glomeruli of Bal / bc mice after injection of P5DMP;

[0083] Attachment Figure 14 The accumulation of material in the heart, liver, and lungs of Bal / bc mice injected with P5DMP;

[0084] Attachment Figure 15 1HNMR spectrum of DMAS (400 MHz, CDCl3, 25°C);

[0085] Attachment Figure 16 1HNMR spectrum of P5DMP (400 MHz, D2O, room temperature);

[0086] Attachment Figure 17 This is the mass spectrum of P5DMP. 114 H 121 O 10 N 11 [M+Br - ] 9+ :m / z=209.20,found:m / z=209.11.[M] 10+ :m / z=180.39, found:m / z=180.08;

[0087] Attachment Figure 18 Figure 1 shows an example of P5DMP synthesis and kidney-specific aggregation. DETAILED DESCRIPTION

[0088] The present invention will be further described below with reference to the examples, but they are not intended to limit the present invention.

[0089] Embodiments of the Invention

[0090] Example 1

[0091] Synthesis of DMAS

[0092] The synthesis path is as follows:

[0093]

[0094] a. Mix 1.33 ml, 13.4 mmol of 4-methylpyridine, 225.5 mg, 2.01 mmol of potassium tert-butoxide and 15 ml of dry DMF, heat the mixture to 60°C for 2 h to obtain product A;

[0095] b. Add 200.0 mg, 1.34 mmol of 4-dimethylaminobenzaldehyde to product A and raise the temperature to 80°C for 8 h to obtain product B;

[0096] c. Cool product B to 25°C and pour into water to obtain a yellow-green precipitate, filter off the yellow-green precipitate and wash with a mixture of ethanol / cold water, then recrystallize from ethanol, and finally dry the crystals to obtain DMAS.

[0097] 1 HNMR (400 MHz, CDC13, 25°C) δ (ppm): 8.50 (d, J = 5.9 Hz, 2H), 7.42 (d, J = 8.8 Hz, 2H), 7.30 (d, J = 6.0 Hz, 2H), 7.21 (s, 1H), 6.79 (d, J = 16.2 Hz, 1H), 6.70 (d, J = 8.8 Hz, 2H), 3.00 (s, 6H) Figure 15 ).

[0098] Example 2

[0099] Synthesis of DMAS

[0100] a. Mix 1.33 ml, 13.4 mmol of 4-methylpyridine, 225.5 mg, 2.01 mmol of potassium tert-butoxide and 15 ml of dry DMF, heat the mixture to 55°C for 3 h to obtain product A;

[0101] b. Add 200.0 mg, 1.34 mmol of 4-dimethylaminobenzaldehyde to product A and raise the temperature to 75°C for 10 h to obtain product B;

[0102] c. Cool product B to 20°C and pour into water to obtain a yellow-green precipitate, filter off the yellow-green precipitate and wash with a mixture of ethanol / cold water, then recrystallize from ethanol, and finally dry the crystals to obtain DMAS.

[0103] Example 3

[0104] a. Mix 1.33 ml, 13.4 mmol of 4-methylpyridine, 225.5 mg, 2.01 mmol of potassium tert-butoxide and 15 ml of dry DMF and heat the mixture to 65°C for 1 h to give product A;

[0105] b. Add 200.0 mg, 1.34 mmol of 4-dimethylaminobenzaldehyde to product A and raise the temperature to 785C for 6 h to give product B;

[0106] c. Cool product B to 30°C and pour into water to give a yellow-green precipitate, filter off the yellow-green precipitate and wash with a mixture of ethanol / cold water, then recrystallise from ethanol and finally dry the crystals to give DMAS.

[0107] Example 4

[0108] Synthesis of P5DMP

[0109] The synthesis route is as follows:

[0110]

[0111] 1) Synthesis of compound 1

[0112] a. Dissolve 10.0 g, 50.4 mmol of 1,4-bis(2-hydroxyethoxy)benzene and 31.5 g, 1205 mmol of triphenylphosphine in 300 mL of dry acetonitrile to give product C;

[0113] b. Slowly add 39.8 g, 120 mmol of carbon tetrabromide to product C with stirring and heat the mixture to 25°C after the addition is complete to give product D;

[0114] c. Stir product D under N2for a further 4 h, then add 200 mL of cold water to give a white precipitate, filter off the white precipitate and wash with a mixture of methanol / water, then recrystallise from methanol and finally dry the crystals to give compound 1;

[0115] 2) Synthesis of compound 2

[0116] a. Dissolve 3.37 g, 11.5 mmol of compound 1 in 200 ml of 1,2-dichloroethane to give product E;

[0117] b. Add 0.349 g, 11.5 mmol of paraformaldehyde to product E under N2, then add 1.63 g, 11.5 mmol of boron trifluoride etherate to the solution and stir at 25°C for 3 h to give product F;

[0118] c. The solvent was removed from F product and the white solid obtained was purified by column chromatography on silica gel using 1 :2 v / v petroleum ether / dichloromethane as eluent to obtain compound 2;

[0119] 3) Synthesis of P5DMP

[0120] 1 g, 0.595 mmol of compound 2, 133.5 mg, 0.59 mmol of DMAS and 60 ml of dry CH3CN were mixed and refluxed for 5 h, then 0.48 ml, 5.95 mmol of pyridine was added to the solution and refluxed for 12 h, finally the solution was removed by rotary evaporator and the precipitate was washed with diethyl ether, the precipitate was dried to obtain P5DMP.

[0121] The1H NMR spectrum and mass spectrum of P5DMP are shown in Figure 16 and 17 respectively.

[0122] 1H NMR (400 MHz, DMSO, 25 °C) δ (ppm): 9.41 (d, J = 6.9 Hz, 19H), 9.07 (s, 1H), 8.67 (s, 10H), 8.24 (d, J = 6.4 Hz, 25H), 7.60 (s, 1H), 6.78 - 6.47 (m, 9H), 5.24 (s, 20H), 4.50 (d, J = 54.1 Hz, 20H), 3.31 - 2.58 (m, 10H). MS (ESI-MS): Calcd for C 114 H 121 O 10 N 11 [M+9Br - ] 9+ : m / z = 209.46, found: m / z = 209.11. [M+10Br - ] 10+ : m / z = 180.52, found: m / z = 180.08. Melting point: 247.0 °C.

[0123] Example 5

[0124] Synthesis of P5DMP

[0125] 1) Synthesis of compound 1

[0126] a. 10.0 g, 50.4 mmol of 1,4-bis(2-hydroxyethoxy)benzene and 31.5 g, 1205 mmol of triphenylphosphine were dissolved in 300 mL of dry acetonitrile to obtain C product;

[0127] b. To C, 39.8 g, 120 mmol of carbon tetrabromide was slowly added while stirring and after the addition was complete the mixture was heated to 20°C to give D;

[0128] c. D was stirred for an additional 3 hours under N2and then 200 mL of cold water was added to give a white precipitate which was filtered off, washed with a mixture of methanol / water and then recrystallized from methanol. The crystals were finally dried to give compound 1;

[0129] 2) Synthesis of compound 2

[0130] a. 3.37 g, 11.5 mmol of compound 1 was dissolved in 200 mL of 1,2-dichloroethane to give E;

[0131] b. To E, 0.349 g, 11.5 mmol of paraformaldehyde was added under N2and then 1.63 g, 11.5 mmol of boron trifluoride etherate was added to the solution. The solution was stirred at 20°C for 4 h to give F;

[0132] c. The solvent was removed from F and the resulting white solid was purified by column chromatography on silica gel using 1:2 v / v petroleum ether / dichloromethane as eluent to give compound 2;

[0133] 3) Synthesis of P5DMP

[0134] Compound 2, 1 g, 0.595 mmol, 133.5 mg, 0.59 mmol of DMAS and 60 mL of dry CH3CN were mixed and refluxed for 3 h and then 0.48 mL, 5.95 mmol of pyridine was added to the solution and refluxed for 10 h. The solution was finally removed by a rotary evaporator and the precipitate was washed with diethyl ether. P5DMP was obtained after drying the precipitate.

[0135] Example 6

[0136] Synthesis of P5DMP

[0137] 1) Synthesis of compound 1

[0138] a. 10.0 g, 50.4 mmol of 1,4-bis(2-hydroxyethoxy)benzene and 31.5 g, 1205 mmol of triphenylphosphine were dissolved in 300 mL of dry acetonitrile to give C;

[0139] b. To C, 39.8 g, 120 mmol of carbon tetrabromide was slowly added while stirring and after the addition was complete the mixture was heated to 30°C to give D;

[0140] c. The D product was stirred for another 5 hours under N2, then 200 mL of cold water was added to obtain a white precipitate, which was filtered off, washed with a mixture of methanol / water, then recrystallized from methanol, and finally the crystals were dried to obtain compound 1;

[0141] 2) Synthesis of compound 2

[0142] a. 3.37 g, 11.5 mmol of compound 1 were dissolved in 200 mL of 1,2-dichloroethane to obtain the E product;

[0143] b. To the E product, 0.349 g, 11.5 mmol of paraformaldehyde were added under N2, then 1.63 g, 11.5 mmol of boron trifluoride etherate were added to the solution, which was stirred for 2 h at 30°C to obtain the F product;

[0144] c. The solvent of the F product was removed, then the white solid obtained was purified by column chromatography on silica gel using 1:2 v / v petroleum ether / dichloromethane as eluent to obtain compound 2;

[0145] 3) Synthesis of P5DMP

[0146] 1 g, 0.595 mmol of compound 2, 133.5 mg, 0.59 mmol of DMAS and 60 mL of dry CH3CN were mixed and refluxed for 7 h, then 0.48 mL, 5.95 mmol of pyridine were added to the solution and refluxed for 20 h, finally the solution was removed by a rotary evaporator and the precipitate was washed with diethyl ether, which was dried to obtain P5DMP.

[0147] The above merely describes preferred specific embodiments of the present application, but the scope of protection of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, can make equivalent replacements or changes within the technical scope disclosed by the present application, which should be covered within the scope of protection of the present application.

Claims

1. A pillar[5]arene-based fluorescent material, characterized by, The chemical structure is shown below:

2. The pillar[5]arene-based fluorescent material according to claim 1, characterized in that, The preparation process includes the following steps: (1) Synthesis of DMAS a. Mix 4-methylpyridine, potassium tert-butoxide and dry DMF, heat the mixture to 55-65°C for 1-3h to obtain product A; b. Add 4-dimethylaminobenzaldehyde to product A and raise the temperature to 75-85°C for 6-10h to obtain product B; c. Cool product B to 20-30°C and pour into water to obtain yellow-green precipitate, filter out the yellow-green precipitate, wash with a mixture of ethanol / cold water, then recrystallize from ethanol, and finally dry the crystals to obtain DMAS, the chemical structure of which is shown below: (2) Synthesis of pillar[5]arene-based fluorescent material 1) Synthesis of compound 1 a. Dissolve 1,4-bis(2-hydroxyethoxy)benzene and triphenylphosphine in dry acetonitrile to obtain product C; b. Slowly add carbon tetrabromide to product C while stirring, then heat the mixture to 20-30°C after the addition is complete to obtain product D; c. Stir product D under N2for another 3-5h, then add cold water to obtain white precipitate, filter out the white precipitate, wash with a mixture of methanol / water, then recrystallize from methanol, and finally dry the crystals to obtain compound 1, the chemical structure of which is shown below: 2) Synthesis of compound 2 a. Dissolve compound 1 in 1,2-dichloroethane to obtain product E; b. Under N2, add paraformaldehyde to product E, then add boron trifluoride etherate to the solution, stir at 20-30°C for 2-4h to obtain product F; c. Remove the solvent from product F using a rotary evaporator, then purify the obtained white solid, i.e. compound 2, by column chromatography on silica gel using petroleum ether / dichloromethane as the eluent, the chemical structure of which is shown below: 3) Synthesis of pillar[5]arene-based fluorescent material Mix 0.595mmol of compound 2, 0.59mmol of DMAS and dry CH3CN, and reflux for 3-7h, then add pyridine to the solution and reflux for 10-20h, finally remove the solution by rotary evaporation, wash the precipitate with ether, dry the precipitate to obtain the pillar[5]arene-based fluorescent material.

3. The pillar[5]arene-based fluorescent material according to claim 1 or 2, characterized in that, The preparation process includes the following steps: (1) Synthesis of DMAS a. Mix 13.4mmol of 4-methylpyridine, 2.01mmol of potassium tert-butoxide and 15ml of dry DMF, heat the mixture to 55-65°C for 1-3h to obtain product A; b. Add 1.34mmol of 4-dimethylaminobenzaldehyde to product A and raise the temperature to 75-85°C for 6-10h to obtain product B; c. Cool product B to 20-30°C and pour into water to obtain yellow-green precipitate, filter out the yellow-green precipitate, wash with a mixture of ethanol / cold water, then recrystallize from ethanol, and finally dry the crystals to obtain DMAS, the chemical structure of which is shown below: (2) Synthesis of pillar[5]arene-based fluorescent material 1) Synthesis of compound 1 a. Dissolve 50.4mmol of 1,4-bis(2-hydroxyethoxy)benzene and 31.5g of triphenylphosphine in 300ml of dry acetonitrile to obtain product C; b. 120 mmol of carbon tetrabromide was slowly added to the C product while stirring, and after the addition was complete, the mixture was heated to 20-30°C to obtain the D product; c. The D product was stirred for another 3-5 hours under N2, then 200 mL of cold water was added to obtain a white precipitate, which was filtered out and washed with a mixture of methanol / water, then recrystallized from methanol, and finally the crystals were dried to obtain compound 1, whose chemical structural formula is shown below: 2) Synthesis of compound 2 a. 11.5 mmol of compound 1 was dissolved in 200 mL of 1,2-dichloroethane to obtain the E product; b. 11.5 mmol of paraformaldehyde was added to the E product under N2, then 11.5 mmol of boron trifluoride etherate was added to the solution, which was stirred at 20-30°C for 2-4 h to obtain the F product; c. The solvent in the F product was removed using a rotary evaporator, then the white solid obtained was purified by column chromatography on silica gel using 1:2 v / v petroleum ether / dichloromethane as the eluent to obtain compound 2, whose chemical structural formula is shown below: 3) Synthesis of pillar[5]arene-based fluorescent material 0.595 mmol of compound 2, 0.59 mmol of DMAS, and 60 mL of dry CH3CN were mixed and refluxed for 3-7 h, then 5.95 mmol of pyridine was added to the solution and refluxed for 10-20 h, and finally the solution was removed by a rotary evaporator, and the precipitate was washed with diethyl ether, and the precipitate was dried to obtain the pillar[5]arene-based fluorescent material.

4. The pillar[5]arene-based fluorescent material according to claim 3, characterized in that: In the synthesis of DMAS, the reaction temperature in step a was 60°C, and the reaction time was 2 h; the reaction time in step b was 80°C, and the reaction time was 8 h; and step c was to cool the B product to 25°C and then pour it into 150 mL of water.

5. The pillar[5]arene-based fluorescent material according to claim 3, characterized in that: In the synthesis of DMAS, the volume ratio of ethanol to water in the mixture of ethanol / cold water in step c was 1:

1.

6. The pillar[5]arene-based fluorescent material of claim 3, wherein: In the synthesis of compound 1, the addition of carbon tetrabromide in step b was at 0°C, and after the addition was complete, the temperature of the mixture was heated to 25°C.

7. The column [5] aromatic hydrocarbon-based fluorescent material according to claim 3, characterized in that: In the synthesis of compound 1, the volume ratio of methanol to water in the mixture of methanol / water in step c was 3:

2.

8. The column [5] aromatic hydrocarbon-based fluorescent material according to claim 3, characterized in that: The reflux time in step 3) for the first time was 5 h, and after the addition of pyridine, the reflux was continued for 12 h.

9. Use of the pillar[5]arene-based fluorescent material according to any one of claims 1-8 in the preparation of a kidney-targeting imaging agent.

10. A kidney-targeting imaging agent containing the pillar[5]arene-based fluorescent material according to any one of claims 1-8.

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