Pda-modified cyclotriveratryl coordination compounds, synthesis method and application thereof

Abstract

The application discloses a PDA modified wheel ring temugin coordination compound and a synthesis method and application thereof. The coordination compound has the ability of amplifying Zn(II) signals, that is, in normal tissues, the MRI signal of the compound itself is weak, and in tissues with Zn(II) distribution, the compound can be easily combined with HSA, so that the signal of Zn(II) can be detected and amplified. The coordination compound has high responsiveness and sensitivity for Zn(II) detection, can be used as an MRI probe for the detection of Zn(II) in living cells, and is suitable for the T 2ex imaging and detection fields.

Description

Technical Field

[0001] This invention belongs to the field of magnetic resonance imaging technology, specifically relating to a class of PDA-modified cyclotinocyanine coordination compounds, their synthesis methods and applications, which amplify the sensitivity to Zn(II) response by changing the water exchange rate. Background Technology

[0002] Divalent zinc (Zn(II)) is abundant in mammalian tissues. As the second most abundant transition metal, it plays a crucial role in the structure, catalysis, and signal transduction of cells. Almost all tissues require Zn(II) for signal transduction, with particularly high concentrations in the pancreas, prostate, and brain. In blood, it exists primarily in a protein-chelated form. Zn(II) is strictly regulated by various transporters, and imbalances in Zn(II) levels in these different tissues are associated with diabetes, Alzheimer's disease, and prostate cancer. Therefore, the detection of Zn(II) levels in the body is valuable for disease diagnosis and treatment.

[0003] For over two decades, researchers have focused on developing and researching various optical instruments and detection methods for detecting free Zn(II) ions, such as the common atomic absorption spectrometry, spectrophotometry, and fluorescence spectroscopy. While these methods have garnered significant attention due to their high selectivity and ease of use, their applicability to in vivo Zn(II) level monitoring is limited. Therefore, optical detectors are largely unable to detect Zn(II) content at the cellular level. Magnetic resonance imaging (MRI) has become a method for physiological imaging of in vivo tissues because it is not affected by tissue penetration. However, MRI itself has lower sensitivity than optical imaging, requiring indirect detection via abundant water protons. The resolution of MRI images is primarily related to the water content within the tissue. However, in some organs and tissues within the human body, the difference in water molecule content between them and diseased tissues is not significant. Therefore, contrast agents (CA) are needed to alter the relaxation rate of water protons in local tissues, thereby improving the imaging contrast between diseased and normal areas.

[0004] When a contrast agent (CA) enters the body, both T1 and T2 are altered. However, different contrast agents have different effects. Some contrast agents primarily shorten T2, making the lesion appear darker; these are called T2 contrast agents, also known as negative contrast agents. These include ferromagnetic and supermagnetic contrast agents, according to the Swift-Connick equation. It can be seen that the factors affecting T2 include: the chemical shift of bound water (Δω) and the exchange rate of water molecules (K). exThe magnetic field strength (B0) is the only variable in T2 contrast agents, where the exchange rate of water molecules is the only variable. Therefore, the imaging effect of T2 can be affected by changing the exchange rate of water molecules. Similarly, contrast agents that shorten T1 and make the lesion brighter are called T1 contrast agents, also known as positive contrast agents. Clinically, T1 contrast agents are commonly used, while T2 contrast agents are rarely reported. However, the effect of T1 contrast agents inevitably varies with concentration, so the development of T2 contrast agents is receiving increasing attention. Dysprosium-based contrast agents are gradually entering the research field due to their stability and low toxicity. These contrast agents themselves do not produce signals; they achieve the imaging effect by changing the relaxation time of surrounding water molecules.

[0005] The N,N-di(2-pyridinemethyl)ethylenediamine structure is closely related to Zn(II), and its role as a specific recognition site for zinc ions has been extensively studied. For example, Gd-DOTA-diBPEN designed by Sherry et al. cannot bind to HSA (human serum albumin) in the absence of Zn(II), but it readily binds to HSA in the presence of Zn(II), effectively increasing the rotation-related time (T0). R This greatly increases relaxation efficiency.

[0006] In summary, a T-based 2ex It is essential to use highly sensitive and highly responsive DPA-modified Zn(II)-responsive contrast agents for early imaging diagnosis of diseases with Zn(II) imbalance, such as diabetes, Alzheimer's disease, and prostate cancer. Summary of the Invention

[0007] Based on the aforementioned prior art, this invention provides a class of PDA-modified cyclopentadiene coordination compounds, their synthesis methods, and applications. These coordination compounds possess the ability to amplify Zn(II) signals; that is, in normal tissues, the compound itself does not emit an MRI signal, but in tissues where Zn(II) is distributed, the compound can easily bind to HSA, thereby detecting and amplifying the Zn(II) signal. These coordination compounds exhibit high responsiveness and sensitivity to Zn(II) detection and can be used as MRI probes for detecting Zn(II) in living cells, suitable for TLC of Zn(II) in tumor or diseased tissues. 2ex In fields such as imaging and detection.

[0008] The technical solution adopted to achieve the above-mentioned objectives of this invention is as follows:

[0009] A class of PDA-modified cyclopentanone coordination compounds have the following structural formula:

[0010]

[0011] A method for synthesizing a class of PDA-modified cyclopentane coordination compounds includes the following steps:

[0012] S1,1,4,7,10-tetraazacyclododecane undergoes a nucleophilic substitution reaction with benzyl chloroformate to produce compound (I), as shown in the following reaction equation:

[0013]

[0014] S2. Under alkaline conditions, compound (I) undergoes a nucleophilic substitution reaction with tert-butyl bromoacetate to produce compound (II), as shown in the following reaction equation:

[0015]

[0016] Or S2', under alkaline conditions, compound (I) first undergoes a nucleophilic substitution reaction with ethyl bromoacetate to generate intermediate compound I. Intermediate compound I then undergoes a nucleophilic substitution reaction with ethyl bromoacetylglycine to generate compound (II), the reaction formula of which is as follows:

[0017]

[0018] Or S2”, under the presence of a base, compound (I) undergoes a nucleophilic substitution reaction with ethyl bromoacetylglycine to produce compound (II), the reaction formula of which is as follows:

[0019]

[0020] S3. Under a hydrogen atmosphere, compound (II) undergoes a hydrogenation-reduction reaction in the presence of a catalyst to produce compound (III), as shown in the following reaction equation:

[0021]

[0022] S4. Under alkaline conditions, N-tert-butoxycarbonyl-1,2-ethylenediamine and 2-chloromethylpyridine or its salts undergo a nucleophilic substitution reaction to generate tert-butyl-(2-(di(pyridine-2-acylmethyl)amino)ethyl)carbamate, as shown in the following reaction formula:

[0023]

[0024] S5, tert-butyl-(2-(di(pyridin-2-acylmethyl)amino)ethyl)carbamate, undergoes detert-butoxycarbonyl protection to generate N1,N1-di(pyridin-2-methyl)ethane-1,2-diamine, as shown in the following reaction formula:

[0025]

[0026] S6. Under alkaline conditions, N1,N1-bis(pyridin-2-methyl)ethane-1,2-diamine undergoes a nucleophilic substitution reaction with chloroacetyl chloride to generate N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide, as shown in the following reaction formula:

[0027]

[0028] S7. Under alkaline conditions, compound (III) undergoes a nucleophilic substitution reaction with N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide to produce compound (IV), as shown in the following reaction formula:

[0029]

[0030] S8. Compound (IV) first undergoes hydrolysis to generate intermediate compound II. Intermediate compound II then undergoes a coordination reaction with trivalent dysprosium ions to generate the PDA-modified cyclopentadiene coordination compound, as shown in the following reaction formula:

[0031]

[0032]

[0033] Furthermore, the nucleophilic substitution reaction in step S1 is carried out at room temperature with a stirring time of 4-12 hours, and the molar ratio of 1,4,7,10-tetraazacyclododecane to benzyl chloroformate is 0.48-0.5:1.0.

[0034] Furthermore, the alkali is selected from at least one of potassium carbonate or potassium bicarbonate.

[0035] Furthermore, in step S2, the reaction temperature for all nucleophilic substitution reactions is 65-75℃, and the reaction time is 8-10h.

[0036] Further, in step S2, the molar ratio of the compound of formula (I) to tert-butyl bromoacetate is 1.0:2.0-2.2; in step S2', the molar ratio of the compound of formula (I) to ethyl bromoacetate is 1.0:1.0-1.2, and the molar ratio of the compound of formula (I) to ethyl bromoacetylglycine is 1.0:1.0-1.2; in step S2", the molar ratio of the compound of formula (I) to ethyl bromoacetylglycine is 1.0:2.0-2.2.

[0037] Furthermore, in step S3, the catalyst is a palladium-on-carbon catalyst, and the hydrogenation reduction reaction is carried out at room temperature for 8-10 hours.

[0038] Furthermore, in step S4, the nucleophilic substitution reaction is carried out at a temperature of 80-110°C for 8-12 hours, and the molar ratio of N-tert-butoxycarbonyl-1,2-ethylenediamine to 2-chloromethylpyridine or its salt is 0.9-1.0:3.0-3.5.

[0039] Furthermore, the nucleophilic substitution reaction in step S6 is carried out at a temperature of -5 to 5°C for 3 to 5 hours, and the molar ratio of N-tert-butoxycarbonyl-1,2-ethylenediamine to chloroacetyl chloride is 0.9 to 1:1.

[0040] Furthermore, the nucleophilic substitution reaction in step S7 is carried out at 65-75°C for 8-10 h, and the molar ratio of compound (III) to N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide is 1.0:2.0-2.2.

[0041] Furthermore, in step S8, the coordination reaction is carried out at room temperature for 6-8 hours, and the molar ratio of compound (IV) to trivalent dysprosium ion is 1.0:0.9-1.0.

[0042] Furthermore, the trivalent dysprosium ion is selected from dysprosium trifluoromethanesulfonate.

[0043] Application of a PDA-modified cyclopentanone coordination compound in the preparation of a divalent zinc ion-responsive T2 contrast agent.

[0044] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0045] 1. The coordination compound of the present invention contains an N,N-di(2-pyridinemethyl)ethylenediamine structure. In tissues where Zn(II) is distributed, the N,N-di(2-pyridinemethyl)ethylenediamine structure can easily bind with HSA. At the same time, Zn(II) can form coordination bonds with the two pyridine structures on the N,N-di(2-pyridinemethyl)ethylenediamine structure. The presence of HSA and Zn(II) will change the relaxation environment of the dysprosium coordination compound, causing the dysprosium coordination compound r2 to change, thereby detecting and amplifying the signal of Zn(II), thus realizing signal amplification and detection in specific tissues, especially in regions of Zn(II) imbalance.

[0046] 2. The series of coordination compounds of the present invention are linked with different numbers of glycine, resulting in different water molecule exchange rates. The T value of the contrast agent is determined by testing the magnitude of the change in its transverse relaxation. 2exImaging effect. Due to the uneven distribution of Zn(II) in various tissues, existing detection methods are prone to misjudgment, as the molar relaxation rate changes with increasing concentration. Therefore, by simultaneously detecting r1 and r2 and then comparing them, the r2 / r1 ratio is used to represent the change in r2, thereby determining T. 2ex This new quantitative method is particularly important for changes in Zn(II) under conditions that produce abnormalities, such as cancer and diabetes.

[0047] 3. The coordination compounds of the present invention have good biocompatibility and excellent water dispersibility, making them suitable for in vivo MRI and promising for early diagnosis of diabetes, Alzheimer's disease, and prostate cancer.

[0048] 4. The coordination compounds of the present invention are simple, the raw materials are cheap and readily available, the synthesis conditions are relatively simple, and the synthesis cost is relatively low. Attached Figure Description

[0049] Figure 1 The graph shows the changes in molar transverse relaxation rate and molar longitudinal relaxation rate of the ring-ringing coordination compound Dy-1 prepared in Example 1 in response to Zn(II).

[0050] Figure 2 The graph shows the changes in molar transverse relaxation rate and molar longitudinal relaxation rate of the ring-ringing coordination compound Dy-2 prepared in Example 2 in response to Zn(II).

[0051] Figure 3 The graph shows the changes in molar transverse relaxation rate and molar longitudinal relaxation rate of the ring-ringing coordination compound Dy-3 prepared in Example 3 in response to Zn(II).

[0052] Figure 4 The graph shows the toxicity test of the cyclohexane coordination compound Dy-1 prepared in Example 1 on human breast cancer cells MCF-7.

[0053] Figure 5 The graph shows the toxicity test of the cyclohexane coordination compound Dy-2 prepared in Example 2 on human breast cancer cells MCF-7.

[0054] Figure 6 The graph shows the toxicity test of the cyclohexane coordination compound Dy-3 prepared in Example 3 on human breast cancer cells MCF-7.

[0055] Figure 7 The graph shows the competitive test results of the cyclopentadienine coordination compound Dy-1 prepared in Example 1 against different metal ions.

[0056] Figure 8 The graph shows the competitive test results of the cyclopentadienine coordination compound Dy-2 prepared in Example 2 against different metal ions.

[0057] Figure 9 The graph shows the competitive test results of the cyclopentadienylene coordination compound Dy-3 prepared in Example 3 against different metal ions. Detailed Implementation

[0058] The present invention will now be described in detail with reference to specific embodiments.

[0059] Example 1

[0060]

[0061] 1. Synthesis of 1,4,7,10-tetraazacyclododecane-1,7-dicarboxylic acid dibenzyl ester hydrochloride (1b)

[0062] 1,4,7,10-tetraazacyclododecane 1a (14.0 g, 81.3 mmol) was dissolved in 300 mL of dichloromethane and cooled to 0 °C. Then, benzyl chloroformate (24.0 mL, 170.7 mmol) was slowly added dropwise. The mixture was heated to room temperature and stirred for 4 hours at room temperature. The reaction was monitored by TLC until it was complete. The mixture was concentrated, and 400 mL of diethyl ether was added to the residue. The mixture was stirred for 1 hour and filtered. The filter cake was washed repeatedly with diethyl ether and dried to give a white solid 1b (38.3 g, 92% yield).

[0063] HRMS: m / z = 441.2505 [M+H] + .

[0064] 2. Synthesis of 4,10-bis(2-(tert-butoxy)-carbonylethyl)-1,4,7,10-tetraazacyclododecane-1,7-dicarboxylic acid dibenzyl ester (1c)

[0065] White solid 1b (6.0 g, 11.7 mmol) and potassium carbonate (8.0 g, 58.5 mmol) were added to acetonitrile (50 mL) and stirred at room temperature for 10 minutes. Then, tert-butyl bromoacetate (2.9 mL, 25.7 mmol) was added dropwise. The mixture was then heated to 65 °C and reacted overnight. After the reaction was completed by LC-MS, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to silica gel rapid column chromatography (dichloromethane / methanol 50:1, v / v) to give a yellow transparent oily liquid 1c (5.0 g, yield 64%).

[0066] HRMS: m / z = 669.3866 [M+H] + .

[0067] 1H NMR (400MHz, CDCl3) δ7.40–7.27(m,10H),5.12(s,4H),3.36(d,J=45.4Hz,12H),2.87(s,6H),2.04(d,J=0.4Hz,2H),1.43(s,18H).

[0068] 3. Synthesis of 1,7-diacetic acid tert-butyl-1,4,7,10-tetraazacyclododecane (1d)

[0069] Dissolve 1c (2.2 g, 3.3 mmol) of yellow transparent oily liquid in methanol (15 mL), add 10% Pd / C (200 mg), transfer to a sealed high-pressure reactor, introduce hydrogen gas and react for 8 hours. After the reaction is complete, filter, concentrate the filtrate to obtain yellow oily liquid 1d, which can be used directly in the next step without purification.

[0070] HRMS: m / z = 401.3126 [M+H] + .

[0071] 1 H NMR (400MHz, CDCl3) δ3.41–3.21 (m, 4H), 3.05–2.56 (m, 16H), 1.42 (d, J = 6.4Hz, 18H).

[0072] 4. Synthesis of N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide (1f)

[0073] N-tert-Butoxycarbonyl-1,2-ethylenediamine (1.4 mL, 8.7 mmol), sodium carbonate (4.6 g, 43.5 mmol), and 2-chloromethylpyridine hydrochloride (4.3 g, 26.1 mmol) were dissolved in ethanol (50 mL) and reacted overnight at 110 °C. After the reaction was completed by TLC monitoring, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to rapid silica gel column chromatography (dichloromethane / methanol 50:1, v / v) to give a yellow oil (2.7 g, 8.0 mmol).

[0074] The yellow oily substance was added to 15 mL of 4 M dioxane chloride solution and reacted at room temperature for 2 hours. After the reaction was completed, the solution was concentrated under reduced pressure to obtain a yellow solid crude product.

[0075] The crude yellow solid product (2.3 g) was dissolved in dichloromethane (50 mL) and cooled to 0 °C. Then, potassium bicarbonate (4 g, 40 mmol) was added and stirred for 30 minutes. Next, a dichloromethane solution containing chloroacetyl chloride (716 μL, 9.0 mmol) (10 mL) was added dropwise. After the addition was complete, the reaction was carried out at 0 °C for 4 hours. After the reaction was completed by LC-MS monitoring, the mixture was concentrated under reduced pressure. The residue was purified by silica gel normal-phase rapid column chromatography (dichloromethane / methanol 20:1, v / v) to give a brownish-yellow oily product 1f (2.1 g, yield 84%).

[0076] HRMS: m / z = 319.1329 [M+H] + .

[0077] 1 H NMR(500MHz, CDCl3)δ8.56–8.50(m,2H),7.61(td,J=7.7,1.7Hz,2H),7.37(d,J=7.8Hz ,2H),7.14(dd,J=6.9,5.4Hz,2H),4.02(s,2H),3.86(s,4H),3.51–3.31(m,2H),2.81–

[0078] 2.72(m,2H).

[0079] 6. Synthesis of 1,7-diacetic acid tert-butyl-4,10-bis(2,2'-bis(2-methylpyridine)aminoethylamino-1,4,7,10-tetraazacyclododecane (1e)

[0080] Yellow oily liquid 1d (1.2 g, 2.9 mmol) and potassium carbonate (2.0 g, 14.5 mmol) were dissolved in acetonitrile (50 mL), heated to 65 °C, and brownish-yellow oily substance 1f (1.9 g, 6.0 mmol) were added. The mixture was stirred and reacted overnight. After the reaction was completed by LC-MS monitoring, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to rapid column chromatography with neutral alumina (dichloromethane / methanol 20:1, v / v). The crude product was then reversed to prepare yellow oily substance 1e (587.3 mg, yield 21%).

[0081] HRMS: m / z = 965.6086 [M+H] + .

[0082] 1H NMR(500MHz,CD3OD)δ8.88(d,J=5.6Hz,4H),8.51(t,J=7.8Hz,4H),8.18–8.05(m,4H),7.96(d,J=6.7Hz,4 H), 4.36 (s, 8H), 4.17 (d, J = 5.7Hz, 4H), 3.56–3.44 (m, 14H), 3.26–2.73 (m, 15H), 1.41 (s, 9H), 1.34 (s, 9H).

[0083] 7. Synthesis of the ring-shaped tinning complex Dy-1

[0084] 5M ethyl hydrochloride solution (15 mL) was added dropwise to a yellow oily substance 1e (530.2 mg, 0.55 mmol). After the addition was complete, the mixture was reacted at room temperature for 2 hours. After the reaction was completed by LC-MS monitoring, the mixture was concentrated to obtain the yellow oily ligand.

[0085] The yellow oily ligand was dissolved in 20 mL of water, and then 1 M sodium hydroxide solution was slowly added dropwise to adjust the pH of the system to 5.5-6.0. During this process, 1 M hydrochloric acid solution was used to simultaneously adjust the pH to maintain it at 5.5-6.0. Dysprosium trifluoromethanesulfonate (301.8 mg, 0.495 mmol) was added while stirring, and the mixture was stirred continuously for 6 hours. The reaction was monitored using the xylenol orange test until the solution color stabilized at a pale yellow. After the reaction was completed as monitored by LC-MS, the final product was purified by preparative high-performance liquid chromatography (mobile phase: water in phase A, acetonitrile in phase B) to obtain the final product. The purity of the final product was analyzed by high-performance liquid chromatography and found to be 95%. The molecular weight of the final product was identified by LC-MS as 1015.1990 [M+H].

[0086] Example 2

[0087]

[0088] 1. Synthesis of 1,7-dicarboxylic acid dibenzyl ester-4-ethyl acetate-1,4,7,10-tetraazacyclododecane (2a)

[0089] White solid 1b (6.0 g, 11.7 mmol) and potassium carbonate (8.0 g, 58.5 mmol) were dissolved in acetonitrile (50 mL). The mixture was stirred at room temperature for 10 minutes and heated to 65 °C. Then, an acetonitrile solution of ethyl bromoacetate (1.5 mL, 12.9 mmol) was added dropwise. After the addition was complete, the mixture was stirred continuously overnight. The reaction was monitored by TLC and LC-MS until the reaction was complete. The mixture was filtered, the filtrate was concentrated, and the residue was subjected to silica gel rapid column chromatography (dichloromethane / methanol 20:1, v / v) to obtain the crude product 2a, which was a pale yellow solid. This crude product was directly added to the next step.

[0090] HRMS: m / z = 567.2869 [M+H] + .

[0091] 2. Synthesis of ethyl bromoacetylglycine (2f)

[0092] Glycine ethyl ester hydrochloride (10.0 g, 71.9 mmol) and potassium bicarbonate (30 g, 217.4 mmol) were dissolved in dichloromethane (300 mL), cooled to 0 °C and stirred for 30 minutes. Then, a dichloromethane solution (20 mL) containing bromoacetyl bromide (6.3 mL, 72 mmol) was added dropwise. The mixture was heated to room temperature and reacted for 8 hours at room temperature. After the reaction was completed by TLC, saturated sodium citrate solution was added to the mixture, followed by dichloromethane extraction (20 mL × 2). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated. The residue was subjected to silica gel rapid column chromatography (petroleum ether / ethyl acetate 30:1, v / v) to give a white solid 2f (12.1 g, yield 81.3%).

[0093] HRMS: m / z = 209.9765 [M+H] + .

[0094] 1 H NMR (500MHz, CDCl3) δ4.24 (q, J = 7.1Hz, 2H), 4.06 (t, J = 6.8Hz, 2H), 3.91 (s, 2H), 1.29 (t, J = 7.2Hz, 3H).

[0095] 3. Synthesis of 1,7-dicarboxylic acid dibenzyl ester-4-ethyl acetate-10-carbonylglycine ethyl ester-1,4,7,10-tetraazacyclododecane (2b)

[0096] A pale yellow solid 2a (3.0 g, 5.7 mmol) and potassium carbonate (4.0 g, 28.5 mmol) were dissolved in acetonitrile (35 mL) and stirred at room temperature for 10 minutes. Then 2f (2.4 g, 11.4 mmol) was added, and the mixture was heated to 65 °C and reacted overnight. After the reaction was completed by TLC and LC-MS monitoring, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to silica gel rapid column chromatography (dichloromethane / methanol 30:1, v / v) to give a yellow oily substance 2b (2.1 g, yield 54.9%).

[0097] HRMS: m / z = 670.3456 [M+H] + .

[0098] 1H NMR(500MHz, CDCl3)δ7.31–7.15(m,10H),5.03(s,4H),4.11–4.01(m,4H), 3.85(s,2H),3.50–2.95(m,12H),2.89–2.54(m,8H),1.17(t,J=7.2Hz,6H).

[0099] 4. Synthesis of 1-ethyl acetate-7-carbonylglycine ethyl ester-1,4,7,10-tetraazacyclododecane (2c)

[0100] Dissolve the yellow oily substance 2b (2.5 g, 3.8 mmol) in ethanol (15 mL), add 10% Pd / C (300 mg), transfer to a sealed high-pressure reactor, introduce hydrogen gas and react for 8 hours. After the reaction is complete, filter, concentrate the filtrate to obtain the yellow oily liquid 2c, which can be used directly in the next step without purification.

[0101] HRMS: m / z = 402.2719 [M+H] + .

[0102] 1 H NMR (500MHz, CDCl3) δ7.98 (s, 1H), 4.06-3.95 (m, 6H), 3.29 (s, 2H), 3.17 (s, 2H), 2.81-2.53 (m, 16H), 1.13 (td, J = 7.2, 4.4Hz, 6H).

[0103] 5. Synthesis of 1-ethyl acetate-7-carbonylglycine ethyl ester-4,10-bis(2,2'-bis(2-methylpyridine)aminoethylamino-1,4,7,10-tetraazacyclododecane (2d)

[0104] Yellow oily liquid 2c (1 g, 2.5 mmol) and potassium carbonate (1.7 g, 12.5 mmol) were dissolved in acetonitrile (20 mL), and the mixture was heated to 65 °C. Then, brownish-yellow oily substance 1f (1.9 g, 6 mmol) was added, and the mixture was stirred overnight. After the reaction was completed by LC-MS monitoring, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to rapid column chromatography with neutral alumina (dichloromethane / methanol 20:1, v / v). The crude product was then reversed to prepare yellow oily substance 2d (256 mg, yield 10.6%).

[0105] HRMS: m / z = 966.5677 [M+H] + .

[0106] 1H NMR (600MHz, CDCl3) δ9.82-9.17(m,4H),8.64–8.26(m,8H),8.12(d,J=7.7Hz,2H),8.00–7.74(m,4H),7.71–7.56(m,4H),7.42– 7.28(m,4H),7.13(dd,J=29.7,14.0Hz,4H),6.55–5.98(m,4H),4.29–3.63(m,22H),3.53–3.26(m,6H),2.83(d,J=59.1Hz,6H).

[0107] 6. Synthesis of the ring-shaped tinning complex Dy-2

[0108] A yellow oily substance (300 mg, 0.31 mmol) was dissolved in water, and 1 M sodium hydroxide solution was added dropwise to adjust the pH to 14. The mixture was stirred overnight. After the reaction was completed, the resulting mixture was adjusted to pH 5.5-6.0 with 1 M hydrochloric acid solution. Dysprosium trifluoromethanesulfonate (170 mg, 0.279 mmol) was added dropwise while stirring. After the addition was complete, the mixture was stirred overnight at room temperature, and the pH was monitored and adjusted every 2 hours. The reaction was monitored using the xylenol orange test until the solution color stabilized at a pale yellow. After the reaction was completed, high-performance liquid chromatography (HPLC) was used for purification (mobile phase: water in phase A, acetonitrile in phase B) to obtain the final product. The purity of the final product was analyzed by HPLC and found to be 98%. The molecular weight of the final product was identified by LC-MS as 1072.1190 [M+H]. Example 3

[0109]

[0110] 1. Synthesis of 1,7-dicarboxylic acid dibenzyl ester-4,10-bis(carbonylglycine ethyl ester)-1,4,7,10-tetraazacyclododecane (3a)

[0111] White solid 1b (6.0 g, 11.7 mmol) and potassium carbonate (8.0 g, 58.5 mmol) were dissolved in acetonitrile (100 mL) and stirred at room temperature for 10 minutes. Then, white solid 2f (5.3 g, 25.7 mmol) was added, and the mixture was heated to 65 °C and reacted overnight. After the reaction was completed by LC-MS monitoring, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to silica gel rapid column chromatography (dichloromethane / methanol 20:1, v / v) to give yellow oil 3a (6.1 g, yield 72%).

[0112] HRMS: m / z = 727.3666 [M+H] + .

[0113] 1 H NMR (400MHz, CDCl3) δ7.37–7.27(m,10H),5.09(s,4H),4.15(q,J=7.1Hz,4H),3.92 (s,4H),3.48(s,8H),3.21(s,4H),2.83(s,8H),1.68(s,2H),1.25(t,J=7.1Hz,6H).

[0114] 2. Synthesis of 1,7-bis(carbonylglycine ethyl ester)-1,4,7,10-tetraazacyclododecane (3b)

[0115] Yellow oily substance 3a (5.0 g, 6.9 mmol) was dissolved in ethanol (40 mL), 10% Pd / C (500 mg) was added, and the mixture was transferred to a sealed high-pressure reactor. Hydrogen gas was introduced and the reaction was carried out for 8 hours. After the reaction was completed, the mixture was filtered, and the filtrate was concentrated to obtain yellow oily liquid 3b. No purification was required, and it was used directly in the next step.

[0116] HRMS: m / z = 459.2933 [M+H] + .

[0117] 1 H NMR (400MHz, CDCl3) δ4.21 (q, J = 7.1Hz, 4H), 4.06 (s, 4H), 3.72 (q, J = 7.0Hz, 2H), 3.34 (d, J = 19.8Hz, 4H), 2.94–2.68 (m, 16H), 1.31 (t, J = 7.1Hz, 5H).

[0118] 3. Synthesis of 1,7-bis(carbonylglycine ethyl ester)-4,10-bis(2,2'-bis(2-methylpyridine)aminoethylamino-1,4,7,10-tetraazacyclododecane (3c)

[0119] Yellow oily liquid 3b (2.0 g, 4.4 mmol) and potassium carbonate (3.0 g, 22.0 mmol) were dissolved in acetonitrile (25 mL), heated to 65 °C, and then brownish-yellow oily substance 1f (2.9 g, 9.0 mmol) were added. The mixture was stirred and reacted overnight. After the reaction was completed by LC-MS monitoring, the mixture was filtered, the filtrate was concentrated, and the residue was subjected to rapid column chromatography with neutral alumina (dichloromethane / methanol 20:1, v / v). The crude product was prepared by reverse phase chromatography to obtain yellow oily substance 3c (566.6 mg, yield 12.6%).

[0120] HRMS: m / z = 1023.5894 [M+H] +

[0121] 1 H NMR (600MHz, CDCl3) δ8.60 (s, 1H), 8.57 (s, 1H), 8.53 (s, 4H), 7.65 (t, J = 7.4Hz, 4H), 7.35 (dd, J = 18.5, 9.1Hz, 4H), 7.17 (d, J = 5. 8Hz,4H),4.21–3.99(m,3H),3.97–3.71(m,16H),3.39–3.04(m,12H),2.77–2.30(m,20H),1.28–1.15(m,3H),1.12–0.93(m,3H).

[0122] 4. Synthesis of the ring-shaped tinning complex Dy-3

[0123] A yellow oily substance 3c (296.4 mg, 0.29 mmol) was dissolved in water, and 1M sodium hydroxide solution was added dropwise to adjust the pH of the system to 14. The mixture was stirred overnight. After the hydrolysis reaction of ethyl ester was monitored by LC-MS, the pH of the resulting mixed product was adjusted to 5.5-6.0 with 1M hydrochloric acid. Dysprosium trifluoromethanesulfonate (159.1 mg, 0.26 mmol) was added dropwise while stirring. After the addition was complete, the reaction was stirred overnight at room temperature, and the pH was monitored continuously, with the pH adjusted every 2 hours. The reaction was stirred overnight at room temperature. The xylenol orange test was used to monitor the reaction until the solution color stabilized at a pale yellow. After the reaction was completed, the final product was purified by preparative high-performance liquid chromatography (HPLC) (mobile phase: water in phase A, acetonitrile in phase B) to obtain the final product. The purity of the final product was analyzed by HPLC and found to be 97%. The molecular weight of the final product was identified by LC-MS as 1129.4420 [M+H].

[0124] Experiment 1: Determination of the longitudinal and molar transverse relaxation rates of the ring-ring tannin coordination compound of the present invention.

[0125] Test method:

[0126] 1. Dissolve Dy-1 separately in distilled water to prepare Dy... 3+ Dy-1 solutions with concentrations of 1.0, 2.0, 3.0, and 4.0 mmol / L were prepared. Dy-2 was dissolved in distilled water to prepare Dy solutions. 3+ Dy-2 solutions with concentrations of 1.0, 2.0, 3.0, and 4.0 mmol / L were prepared. Dy-3 was dissolved in distilled water to prepare Dy solutions. 3+ Dy-3 solutions with concentrations of 1.0, 2.0, 3.0, and 4.0 mmol / L.

[0127] 2. Divide each group of different Dy 3+The Dy-1 concentration solution was treated as follows: 0.5 equivalents (0.5 equivalents refers to the amount of Zn in the ZnCl2 solution) were added to each solution. 2+ Concentration of Dy in Dy-1 solution 3+ Four samples were prepared in a ZnCl2 solution (with distilled water as solvent) with a concentration ratio of 0.5. The four samples were then transferred into 4 mm NMR tubes. The T1 values ​​of the four samples were measured on a Bruker 400M NMR spectrometer using the saturation inversion recovery method (instrument parameters: DS=4, NS=8, D1=1s, D20=50μs, L20=15000). The molar longitudinal relaxation rate r1 was calculated by computer fitting.

[0128] The T2 values ​​of four samples were tested using the spin echo method on a Bruker 400M nuclear magnetic resonance spectrometer (instrument parameters: DS=4, NS=8). The molar transverse relaxation rate r2 was calculated by computer fitting.

[0129] 3. Divide each group of different Dy 3+ The Dy-1 concentration solution was mixed with 0, 1, 1.5, 2, and 2.5 equivalents of ZnCl2 solution, respectively, and tested according to the method in step 2.

[0130] 4. Process each group of different Dy groups according to the methods in steps 2 and 3. 3+ Concentration of Dy-2 solution and different Dy concentrations in each group 3+ Dy-3 concentration solution.

[0131] Experimental results:

[0132] 1. Dy-1 solution on Zn 2+ The graph shows the changes in molar transverse relaxation rate and molar longitudinal relaxation rate under the response. Figure 1 As shown, by Figure 1 It can be seen that the molar longitudinal relaxation rate r1 of coordination compound Dy-1 varies with Zn 2+ The concentration increase did not significantly change the concentration, while the molar transverse relaxation rate r2 increased with Zn. 2+ The ratio of T2 to T1 gradually increases with increasing concentration. A control with a less pronounced change in T1 can be used to represent the degree of change in T2. ​​That is, T2 / T1 decreases with increasing concentration, ranging from 7-11 mM. -1 s -1 between.

[0133] 2. Dy-2 solution on Zn 2+ The graph shows the changes in molar transverse relaxation rate and molar longitudinal relaxation rate under the response. Figure 2 As shown, coordination compound Dy-2 introduces a glycine structure based on coordination compound Dy-1, from Figure 2It can be seen that the molar longitudinal relaxation rate r1 of the coordination compound Dy-2 varies with Zn 2+ The concentration increase did not significantly change the concentration, while the molar transverse relaxation rate r2 increased with Zn. 2+ The molar relaxation rate r2 gradually decreases with increasing concentration, and is 2-3 times higher than that of the coordination compound Dy-1. T1, which shows little change, can be used as a control to represent the degree of change in T2. ​​The T2 / T1 ratio decreases with increasing concentration, ranging from 12-18 mM. -1 s -1 Between these values, the T2 / T1 value increased by 2-3 times, demonstrating better T2 responsiveness.

[0134] 3. Dy-3 solution on Zn 2+ The graph shows the changes in molar transverse relaxation rate and molar longitudinal relaxation rate under the response. Figure 3 As shown, coordination compound Dy-3 introduces two glycine structures based on coordination compound Dy-1, from... Figure 3 It can be seen that the molar longitudinal relaxation rate r1 of the coordination compound Dy-3 varies with Zn 2+ The concentration increase did not significantly change the concentration, while the molar transverse relaxation rate r2 increased with Zn. 2+ The ratio of T2 to T1 gradually decreases with increasing concentration. A control with a less pronounced change in T1 can be used to represent the degree of change in T2. ​​That is, T2 / T1 decreases with increasing concentration, ranging from 2-5 mM. -1 s -1 between.

[0135] Experiment 2: Cytotoxicity test of the cyclohexane coordination compound of the present invention

[0136] Test method:

[0137] Human breast cancer cells MCF-7 were seeded in 96-well plates for 24 hours, and then different amounts of Dy were added. 3+ Human cell basal culture medium solutions of Dy-1 / Dy-2 / Dy-3 concentrations (0, 25, 50, 100, 300, 600 μg / mL) were incubated for 24 h. Subsequently, 200 μL of 5 mg / mL MTT solution was added to each well, and incubation was continued for another 4 h. After removing the solution from the wells, the wells were washed with PBS, and the survival rate of human breast cancer cells MCF-7 was calculated based on the average of 6 parallel wells.

[0138] Experimental results:

[0139] The survival of human breast cancer cells MCF-7 after treatment with different concentrations of the cyclohexane coordination compound Dy-1 is as follows: Figure 4 As shown, the survival of human breast cancer cells MCF-7 after treatment with different concentrations of the cyclohexane coordination compound Dy-2 is as follows: Figure 5As shown, the survival of human breast cancer cells MCF-7 after treatment with different concentrations of the cyclohexane coordination compound Dy-3 is as follows: Figure 6 As shown, by Figure 4-6 As shown, treatment with Dy-1, Dy-2, and Dy-3 resulted in a survival rate of over 95% for human breast cancer cells MCF-7. Furthermore, increasing the concentration of the cyclohexane complex had little effect on the survival rate of MCF-7 cells; even at a concentration of 600 μg / mL, the survival rate of MCF-7 cells remained above 95%.

[0140] Experiment 3: Competitive testing of the invented ring-shaped tinning coordination compound against metal ions.

[0141] Test method:

[0142] 1. Prepare 50mM stock solutions of MgCl2, FeCl3, CaCl2, CuCl2, CuCl and ZnCl2 using distilled water respectively;

[0143] 2. Prepare Dy separately using distilled water. 3+ A 50 μM Dy-1 / Dy-2 / Dy-3 solution;

[0144] 3. Treat the Dy-1 solution as follows: Add 0 and 0.5 (0.5 equivalent refers to the amount of Mg in the MgCl2 solution) respectively. 2+ Concentration of Dy in Dy-1 solution 3+ Five MgCl2 solutions with concentration ratios of 0.5, 1.0, 1.5, and 2.0 equivalents were prepared to obtain five test samples. The five test samples were transferred into 4 mm NMR tubes, and the T2 values ​​of the five test samples were tested using the spin echo method on a Bruker 400M NMR spectrometer (instrument parameters: DS=4, NS=8). The molar transverse relaxation rate r2 was calculated by computer fitting.

[0145] 4. The competition test between coordination compound Dy-1 and FeCl3, CaCl2, CuCl2, CuCl and ZnCl2 was carried out in step 3.

[0146] 5. Perform the competition tests of coordination compound Dy-2 and coordination compound Dy-3 with MgCl2, FeCl3, CaCl2, CuCl2, CuCl and ZnCl2 according to the methods in steps 3 and 4.

[0147] Experimental results:

[0148] 1. The competitive results of coordination compound Dy-1 against six metal ions: Mg, Fe, Ca, Cu, Cu, and Zn are as follows: Figure 7 As shown, by Figure 7It can be seen that the molar transverse relaxation rate r2 of coordination compound Dy-1 in the presence of the other five metal ions ranges from 7 to 8 mM. -1 s -1 Between, and in Zn 2+ There exists a lower molar transverse relaxation rate r 2ex 2-3 mm higher -1 s -1 That is, the coordination compound Dy-1 for Zn 2+ The relatively short transverse relaxation time T2 indicates that the coordination compound Dy-1 has a strong effect on Zn. 2+ The response sensitivity is better compared to the other five metal ions.

[0149] 2. The competitive results of coordination compound Dy-2 against six metal ions: Mg, Fe, Ca, Cu, Cu, and Zn are as follows: Figure 8 As shown, by Figure 8 It can be seen that the molar transverse relaxation rate r2 of coordination compound Dy-2 increases in the presence of all six metal ions. The molar transverse relaxation rate r2 of coordination compound Dy-2 in the presence of the other five metal ions ranges from 16 to 18 mM. -1 s -1 Between, in Zn 2+ The molar transverse relaxation rate r2 in the presence of Zn is lower than that in the presence of the other five metals, indicating that the coordination compound Dy-2 has a lower molar transverse relaxation rate r2 for Zn. 2+ The relatively long transverse relaxation time T2 indicates that the coordination compound Dy-2 has a strong effect on Zn. 2+ Its response sensitivity is low.

[0150] 3. The competitive results of coordination compound Dy-3 against six metal ions: Mg, Fe, Ca, Cu, Cu, and Zn are as follows: Figure 9 As shown, by Figure 9 It can be seen that the molar transverse relaxation rate r2 of coordination compound Dy-3 increases in the presence of all six metal ions, while the molar transverse relaxation rate r2 in the presence of the other five metal ions ranges from 16 to 18 mM. -1 s -1 Between, in Zn 2+ There exists a lower molar transverse relaxation rate r 2ex Compared to the other five metal ions, the molar transverse relaxation rate r2 is lower, indicating that the coordination compound Dy-3 has a lower molar transverse relaxation rate for Zn. 2+ The relatively long transverse relaxation time T2 indicates that the coordination compound Dy-3 has a strong effect on Zn. 2+ Its response sensitivity is low.

Claims

1. A class of PDA-modified cyclopentanone coordination compounds, characterized in that... Its structural formula is as follows:

2. A method for synthesizing a class of PDA-modified cyclopentanone coordination compounds, characterized in that... Includes the following steps: S1,1,4,7,10-tetraazacyclododecane undergoes a nucleophilic substitution reaction with benzyl chloroformate to produce compound (I), as shown in the following reaction equation: S2. Under alkaline conditions, compound (I) undergoes a nucleophilic substitution reaction with tert-butyl bromoacetate to produce compound (II), as shown in the following reaction equation: Or S2', under alkaline conditions, compound (I) first undergoes a nucleophilic substitution reaction with ethyl bromoacetate to generate intermediate compound I. Intermediate compound I then undergoes a nucleophilic substitution reaction with ethyl bromoacetylglycine to generate compound (II), the reaction formula of which is as follows: Or S2”, under the presence of a base, compound (I) undergoes a nucleophilic substitution reaction with ethyl bromoacetylglycine to produce compound (II), the reaction formula of which is as follows: S3. Under a hydrogen atmosphere, compound (II) undergoes a hydrogenation-reduction reaction in the presence of a catalyst to produce compound (III), as shown in the following reaction equation: S4. Under alkaline conditions, N-tert-butoxycarbonyl-1,2-ethylenediamine and 2-chloromethylpyridine or its salts undergo a nucleophilic substitution reaction to generate tert-butyl-(2-(di(pyridine-2-acylmethyl)amino)ethyl)carbamate, as shown in the following reaction formula: S5, tert-butyl-(2-(di(pyridin-2-acylmethyl)amino)ethyl)carbamate, undergoes detert-butoxycarbonyl protection to generate N1,N1-di(pyridin-2-methyl)ethane-1,2-diamine, as shown in the following reaction formula: S6. Under alkaline conditions, N1,N1-bis(pyridin-2-methyl)ethane-1,2-diamine undergoes a nucleophilic substitution reaction with chloroacetyl chloride to generate N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide, as shown in the following reaction formula: S7. Under alkaline conditions, compound (III) undergoes a nucleophilic substitution reaction with N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide to produce compound (IV), as shown in the following reaction formula: S8. Compound (IV) first undergoes hydrolysis to generate intermediate compound II. Intermediate compound II then undergoes a coordination reaction with trivalent dysprosium ions to generate the PDA-modified cyclotinocyanine coordination compound, as shown in the following reaction formula:

3. The method for synthesizing the PDA-modified cyclopentanone coordination compound according to claim 2, characterized in that: The nucleophilic substitution reaction in step S1 is carried out at room temperature with a stirring time of 4-12 hours, and the molar ratio of 1,4,7,10-tetraazacyclododecane to benzyl chloroformate is 0.48-0.5:1.

0.

4. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: The alkali is selected from at least one of potassium carbonate or potassium bicarbonate.

5. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: In step S2, all nucleophilic substitution reactions are carried out at a temperature of 65-75°C for 8-10 hours.

6. The method for synthesizing the PDA-modified ring-ringingin coordination compound according to claim 2, characterized in that: In step S2, the molar ratio of compound (I) to tert-butyl bromoacetate is 1.0:2.0-2.2; in step S2', the molar ratio of compound (I) to ethyl bromoacetate is 1.0:1.0-1.2, and the molar ratio of compound (I) to ethyl bromoacetylglycine is 1.0:1.0-1.2; in step S2", the molar ratio of compound (I) to ethyl bromoacetylglycine is 1.0:2.0-2.

2.

7. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: In step S3, the catalyst is a palladium-on-carbon catalyst, and the hydrogenation reduction reaction is carried out at room temperature for 8-10 hours.

8. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: In step S4, the nucleophilic substitution reaction is carried out at a temperature of 80-110℃ for 8-12 hours, and the molar ratio of N-tert-butoxycarbonyl-1,2-ethylenediamine to 2-chloromethylpyridine or its salt is 0.9-1.0:3.0-3.

5.

9. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: The nucleophilic substitution reaction in step S6 is carried out at a temperature of -5 to 5°C for 3 to 5 hours, and the molar ratio of N-tert-butoxycarbonyl-1,2-ethylenediamine to chloroacetyl chloride is 0.9 to 1:

1.

10. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: The nucleophilic substitution reaction in step S7 is carried out at 65-75°C for 8-10 hours, and the molar ratio of compound (III) to N-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2-chloroacetamide is 1.0:2.0-2.

2.

11. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: In step S8, the coordination reaction is carried out at room temperature for 6-8 hours, and the molar ratio of compound (IV) to trivalent dysprosium ion is 1.0:0.9-1.

0.

12. The method for synthesizing the PDA-modified cyclopentadiene coordination compound according to claim 2, characterized in that: The trivalent dysprosium ion is selected from dysprosium trifluoromethanesulfonate.

13. The use of the PDA-modified cyclopentadiene coordination compound of claim 1 in the preparation of a divalent zinc ion-responsive T2 contrast agent.

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