A method for preparing and using a platinum (IV) prodrug with a glycyrrhetinic acid derivative as a ligand

Abstract

The application belongs to the technical field of pharmaceutical chemistry, and specifically discloses a glycyrrhetinic acid derivative as a ligand of platinum (IV) prodrug as well as a preparation method and application thereof. The glycyrrhetinic acid with anti-cancer activity and capable of targeting glycyrrhetinic acid receptors is introduced into an axial position of a platinum (IV) complex, and a series of multifunctional platinum (IV) prodrugs are prepared. Research results show that the platinum (IV) complexes have good anti-proliferation activity on tested cancer cells, especially the activity on liver cancer cells HepG-2 and A549 is better than that of a positive drug, and the toxicity on human normal liver cells (HL-7702 and L02 cells) is lower than that of cisplatin. In addition, a representative compound can effectively inhibit tumor growth in HepG-2 and A549 xenograft tumor models, and has no obvious effect on the weight of mice, showing the characteristics of low toxicity and high efficacy. Therefore, the glycyrrhetinic acid-platinum (IV) prodrug based on the targeting glycyrrhetinic acid receptor has potential use in targeted treatment of human liver cancer.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical synthesis technology and relates to the preparation of platinum (IV) prodrugs, specifically to a platinum (IV) prodrug with glycyrrhetinic acid derivatives as ligands, its preparation method and application. Background Technology

[0002] Liver cancer is a malignant tumor with high mortality and morbidity rates. Currently, the most effective treatments are surgical resection and liver transplantation. Because early symptoms of liver cancer are difficult to detect, most patients are diagnosed at an advanced stage, missing the optimal window for surgical treatment, and therefore most patients can only choose chemotherapy. Platinum-based anticancer drugs, such as cisplatin, carboplatin, and oxaliplatin, are first-line chemotherapy drugs that can be used alone or in combination with other anticancer drugs to treat liver cancer. However, their severe toxic side effects and drug resistance limit their widespread clinical application. Therefore, developing a novel platinum-based anticancer drug with strong targeting, high efficacy, and low toxicity has significant academic importance and potential application value.

[0003] Studies have found that glycyrrhetinic acid (GA), a pentacyclic triterpenoid compound extracted from the traditional Chinese medicine licorice, possesses multiple effective anti-tumor mechanisms against liver cancer. More importantly, research indicates that GA can bind to the glycyrrhizic acid receptor in liver cancer cells, making it a ligand that specifically binds to the GA receptor, offering significant advantages in mediating drug delivery for liver cancer treatment. On the one hand, platinum (IV) complexes, compared to platinum (II) complexes, have advantages such as chemokinetic inertness, low toxicity, and the ability to serve as prodrugs for platinum (II) complexes. Therefore, we introduced a GA compound that targets the GA receptor and possesses its own anti-cancer activity into the axial position of a platinum (IV) complex to design and synthesize a novel class of platinum (IV) anti-tumor drugs for liver cancer with strong targeting, high efficacy, and low toxicity. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a platinum (IV) prodrug with glycyrrhetinic acid, which targets the glycyrrhetinic acid receptor, as a ligand. This prodrug can effectively treat liver cancer while overcoming the disadvantages of existing cisplatin-based antitumor drugs, such as easy drug resistance and large toxic side effects. The present invention further provides a method for synthesizing this platinum (IV) prodrug.

[0005] This invention is achieved through the following technical solution:

[0006] A platinum (IV) prodrug with a glycyrrhetinic acid derivative as a ligand, the structural formula of which is shown in Formula 11, Formula 12, Formula 13, Formula 14, Formula 20 or Formula 21:

[0007]

[0008] A further improvement to the present invention is as follows:

[0009] The preparation method of the above-mentioned platinum (IV) prodrug compounds 11-14 with glycyrrhetinic acid as a ligand includes the following steps;

[0010] (1) Dissolve compound 1 in pyridine solution, then add acetic anhydride, stir overnight at room temperature to obtain compound 2, wherein the amount of compound used is in molar amount, compound 1: acetic anhydride = 1: 2~4;

[0011] (2) Dissolve compound 2 in DMF, and stir it overnight at 40-60°C with 2-(boc-amino)ethyl bromide or 3-(boc-amino)propyl bromide in the presence of potassium carbonate to obtain compound 3 or 4. The amount of compound used is based on the molar ratio of compound 2: 2-(boc-amino)ethyl bromide or 3-(boc-amino)propyl bromide: potassium carbonate = 1:1-1.5:1.8-2.2.

[0012] (3) Dissolve compound 3 or 4 in dry DCM, add TFA, and react at room temperature for 2-4 hours to obtain compound 5 or 6. The amount of compound used is based on the molar amount, and the ratio of compound 3 or 4 to TFA is 1:2-4.

[0013] (4) Dissolve compound 5 or 6 in DMF, add triethylamine, then add glutaric anhydride, stir overnight at 50-80°C to obtain compound 7 or 8, wherein the amount of compound used is in molar amount, and the ratio of compound 5 or 6:triethylamine:glutaric anhydride is 1:1-3:2-4.

[0014] (5) Dissolve compound 7 or 8 in DMF, add TBTU and triethylamine, then add complex 9 or 10, stir overnight at 20-40°C to obtain compound 11-14, wherein the amount of compound used is in molar amounts, and the ratio of compound 7 or 8:TBTU:triethylamine:complex 9 or 10 is 1:1-1.5:1-1.5:0.8-1.2.

[0015] The synthesis route is shown below:

[0016]

[0017] Furthermore, in the above preparation method, steps (1) to (5) also include a separation and purification step.

[0018] The preparation method of the above-mentioned platinum (IV) prodrug compound 20 or 21 with glycyrrhetinic acid as a ligand includes the following steps;

[0019] (1) Dissolve compound 2 in a dry DCM solution, add EDCI, DMAP and 3-buten-1-ol, and stir overnight at 20-40°C to obtain compound 16. The amounts of the compounds are calculated by molar ratio as follows: compound 2: EDCI: DMAP: 3-buten-1-ol = 1: 1.8-2.2: 1.2-1.8: 1.2-1.8;

[0020] (2) Dissolve compound 16 in methanol, add copper acetate monohydrate, stir for 3-5 minutes, then add compound 17, and then add sodium ascorbate. Stir overnight at 30-40°C to obtain compound 18. The amount of compounds used is calculated by molar ratio as follows: compound 16: copper acetate monohydrate: compound 17: sodium ascorbate = 1: 0.1-0.3: 1.2-1.8: 0.2-0.6.

[0021] (3) Dissolve compound 18 in dry DCM, add succinic anhydride and DMAP, heat under reflux overnight to obtain compound 19, wherein the amount of compound used is in molar amounts, and the ratio of compound 18: succinic anhydride: DMAP is 1:1.8~2.2:0.1~0.3;

[0022] (4) Dissolve compound 19 in DMF, add TBTU and triethylamine, then add complex 9 or 10, stir overnight at 25-35°C to obtain compound 20 or 21, wherein the amount of compound used is in molar amounts, and the ratio of compound 19:TBTU:triethylamine:complex 9 or 10 is 1:1-1.5:1-1.5:0.8-1.2.

[0023] The synthesis route is shown below:

[0024]

[0025] Furthermore, in the above preparation method, steps (1) to (5) also include a separation and purification step.

[0026] A further improvement of the present invention is as follows:

[0027] The application of the above-mentioned platinum (IV) prodrug compounds 11-14, 20, and 21 with glycyrrhetinic acid as a ligand in the treatment of liver cancer.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention introduces glycyrrhetinic acid, which targets the glycyrrhetinic acid receptor and possesses inherent anticancer activity, into the axial position of platinum (IV) complexes, preparing a series of multifunctional platinum (IV) prodrugs. Validation data from this invention show that these platinum (IV) complexes exhibit good antiproliferative activity against tested cancer cells, particularly against HepG-2 liver cancer cells, where their activity is superior to positive control drugs, and their toxicity to normal human liver cells (HL-7702 and LO2 cells) is lower than that of cisplatin. Furthermore, representative compounds effectively inhibited tumor growth in HepG-2 and A549 xenograft tumor models with minimal impact on mouse body weight, demonstrating low toxicity and high efficacy. Therefore, the glycyrrhetinic acid-platinum (IV) prodrugs based on glycyrrhetinic acid receptor targeting disclosed in this invention have potential applications in targeted therapy of human liver cancer. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the antitumor activity of compound 20 obtained in this invention.

[0031] In the diagram, A and E are mouse grouping diagrams; B and F are tumor volume changes in each group; C and G are mouse weight changes in each group; and D and H are tumor weights in each group. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments.

[0033] Abbreviations for the experimental section:

[0034] Experimental abbreviations: DCM, dichloromethane; MeOH, methanol; EA, ethyl acetate; PE, petroleum ether; CDDP, cisplatin; DMF, N,N-dimethylformamide; TLC, thin-layer chromatography; EtOH, ethanol; Et3N, triethylamine; TBTU, O-benzotriazole-N,N,N,N-tetramethylurea tetrafluoroborate; HepG-2, human hepatocellular carcinoma cells; Bel-7404, human hepatocellular carcinoma cells; MCF-7, human breast cancer cells; A549, human lung cancer cells; HL-7702, normal human hepatocytes; L02, normal human hepatocytes.

[0035] Example 1: Preparation of Compound 2

[0036] Compound 1 (5.0 g, 10.64 mmol) was dissolved in pyridine (30 mL), and then acetic anhydride (3.3 g, 31.92 mmol) was added. The mixture was stirred overnight at room temperature, and the reaction was monitored by thin-layer chromatography. After the reaction was complete, the solvent was removed under reduced pressure, and the crude product was washed with water (500 mL). It was then washed with petroleum ether, and the product was vacuum-sealed to give compound 2 (4.7 g, white solid, 87% yield), which did not require further purification. 1HNMR(500MHz, CDCl3)δ5.71(s,1H),4.51(dd,J=11.7,4.7Hz,1H),2.81–2.77(m,1H),2.36(s,1 H),2.18(dd,J=13.5,2.9Hz,1H),2.04(s,3H),2.03–1.91(m,3H),1.85–1.79(m,1H),1.73–1.5 6(m,5H),1.48–1.39(m,4H),1.36(s,3H),1.34–1.30(m,1H),1.22(s,3H),1.19–1.18(m,1H),1 .16(s,3H),1.12(s,3H),1.07–1.01(m,2H),0.87(s,6H),0.83(s,3H),0.80(d,J=11.1Hz,1H). 13 C NMR (125MHz, CDCl3) δ200.39,181.78,171.08,169.55,128.41,80.66,61.71,55.03,48.26,45.48,43.82,43.22,40.85,38.78,38.06,37.72 ,36.95,32.72,31.87,30.91,28.55,28.46,28.06,26.48,26.41,23.58,23.35,21.31,18.69,17.38,16.69,16.41.HR-MS(m / z)(ESI):calcd for C 32 H 48 O5[M+H] + :513.3580; found:513.3501.

[0037] Example 2: Preparation of compounds 3 and 4

[0038] Compound 2 (2.0 g, 3.91 mmol) was dissolved in dry DMF (10 mL), followed by the addition of potassium carbonate (1.07 g, 7.82 mmol) and potassium iodide (650 mg, 3.91 mmol), and then 2-(boc-amino)ethyl bromide (1.1 g, 4.69 mmol) or 3-(boc-amino)propyl bromide (1.2 g, 4.69 mmol). The mixture was stirred overnight at 50 °C. After the reaction was complete, the reaction mixture was extracted with dichloromethane (150 mL) and saturated brine (250 mL). The organic phase was washed three times with saturated brine, dried over anhydrous Na₂SO₄, and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography, eluting with petroleum ether / ethyl acetate, to give a white solid compound 3 or 4.

[0039] Compound 3, 1.93 g, yield: 75.4%. 1 H NMR (400MHz, CDCl3) δ5.63(s,1H),4.71(s,1H),4.50(dd,J=11.6,4.8Hz,1H),4.20–4.09(m,2H),3.38(d,J=4.3Hz, 2H),2.80–2.77(m,1H),2.34(s,1H),2.11–2.06(m,1H),2.04(s,3H),2.02–1.89(m,3H),1.85–1.68(m,2H),1.64–1. 56(m,4H),1.49(d,J=11.1Hz,1H),1.42(s,9H),1.38(d,J=3.2Hz,2H),1.35(s,3H),1.33–1.24(m,3H),1.22–1.18(m ,1H),1.15(s,3H),1.14(s,3H),1.11(s,3H),1.07–0.99(m,2H),0.86(s,6H),0.79(s,3H).HR-MS(m / z)(ESI):calcd for C 39 H 61 NO7[M+Na] + :678.4646; found:678.4356.

[0040] Compound 4, 1.85 g, yield: 70.6%. 1 H NMR (400MHz, CDCl3) δ5.62(s,1H),4.78(s,1H),4.50(dd,J=11.6,4.8Hz,1H),4.15(t,J=6.5Hz,2H),4.11(d,J=7.1Hz, 1H),3.18(d,J=2.8Hz,2H),2.81–2.76(m,1H),2.35(s,1H),2.10–2.06(m,1H),2.04(s,3H),2.01–1.88(m,3H),1.83–1 .78(m,2H),1.68–1.56(m,4H),1.51–1.48(m,1H),1.42(s,9H),1.38(d,J=3.2Hz,2H),1.35(s,3H),1.32–1.26(m,4H), 1.19(d,J=1.1Hz,1H),1.15(s,6H),1.11(s,3H),1.05–0.98(m,2H),0.87(s,6H),0.79(s,3H).HR-MS(m / z)(ESI):calcd for C 40 H 63NO7[M+Na] + :692.4502; found:692.4564.

[0041] Example 3: Preparation of compounds 5 and 6

[0042] Compound 3 (2.75 mmol) or compound 4 (2.75 mmol) was dissolved in a dry DCM (15 mL) solution at 0 °C, and TFA (0.94 g, 8.25 mmol) was added. The mixture was stirred at 0 °C for 3 h, and the reaction was monitored by thin-layer chromatography. After the reaction was complete, the pH of the solution was adjusted to 8–9 with saturated sodium bicarbonate solution, and the mixture was extracted with dichloromethane (2 × 150 mL). The organic phase was washed three times with saturated brine, dried over anhydrous Na₂SO₄, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography, eluting with a dichloromethane / methanol solution containing 0.5% TEA to give a white solid compound 5 or 6.

[0043] Compound 5, 1.2 g, yield: 78.4%. 1 H NMR (400MHz, CDCl3) δ5.88–5.71(m,2H),5.57(s,1H),4.50(dd,J=11.5,4.7Hz,1H),4.24–4.11(m,9.2Hz,2H) ,2.98(t,J=7.3Hz,2H),2.74–2.71(m,1H),2.36(s,1H),2.10–2.06(m,1H),2.03(s,3H),2.01–1.95(m,3H),1. 90–1.76(m,2H),1.69–1.56(m,5H),1.47–1.38(m,2H),1.35(s,3H),1.30–1.24(m,3H),1.22–1.1.19(m,1H), 1.13(s,3H),1.12(s,3H),1.10(s,3H),1.03–0.94(m,2H),0.86(s,6H),0.78(s,3H).HR-MS(m / z)(ESI):calcd for C 34 H 53 NO5[M+H] + :556.4002; found:556.3996.

[0044] Compound 6, 1.1 g, yield: 70.5%. 1H NMR(400MHz, CDCl3)δ5.62(s,1H),4.49(dd,J=11.6,4.8Hz,1H),4.17–4.07(m,2H),2.94(t,J=5.5Hz ,2H),2.79–2.74(m,1H),2.33(s,1H),2.10(dd,J=13.7,3.6Hz,1H),2.03(s,3H),2.01–1.93(m,3H),1 .91–1.74(m,4H),1.68–1.56(m,5H),1.43–1.37(m,2H),1.34(s,3H),1.32–1.17(m,4H),1.15(s,3H) ,1.13(s,3H),1.10(s,3H),1.06–0.97(m,2H),0.85(s,6H),0.78(s,3H).HR-MS(m / z)(ESI):calcdfor C 35 H 55 NO5[M+H] + :570.4158; found:570.4153.

[0045] Example 4: Preparation of compounds 7 and 8

[0046] Compound 5 (1.58 mmol) or 6 (1.58 mmol) and Et3N (319 mg, 3.16 mmol) were added separately to DMF (5 mL) solution, followed by glutaric anhydride (540 mg, 4.75 mmol). The mixture was stirred overnight at 60 °C, and the reaction was monitored by thin-layer chromatography. After the reaction was complete, 150 mL of dichloromethane was added to the reaction system, and the mixture was washed three times with saturated brine. The organic phase was dried over anhydrous Na2SO4 and concentrated to obtain the crude product, which was then purified by silica gel column chromatography eluting with dichloromethane / methanol solution to obtain a white solid compound 7 or 8.

[0047] Compound 7,820 mg, yield: 78.1%. 11H NMR (400 MHz, DMSO-d6) δ 12.01 (s, 1H), 7.92 (t, J = 5.5 Hz, 1H), 5.45 (s, 1H), 4.42 (dd, J = 11.8, 4.5 Hz, 1H), 4.05 (t, J = 5.6 Hz, 2H), 3.29 (dd, J = 11.2, 5.6 Hz, 2H), 2.65–2.61 (m, 1H), 2.40 (s, 1H), 2.18 (t, J = 7.5 Hz, 2H), 2.11 (t, J = 7.3 Hz, 2H), 2.06–1.98 (m, 5H), 1.87–1.72 (m, 4H), 1.70–1.62 (m, 4H), 1.59–1.39 (m, 3H), 1.39 (d, J = 4.0 Hz, 2H), 1.36 (s, 3H), 1.33–1.15 (m, 4H), 1.10 (s, 3H), 1.06 (s, 3H), 1.04 (s, 3H), 0.98–0.82 (m, 2H), 0.82 (s, 6H), 0.74 (s, 3H). HR-MS (m / z) (ESI): calcd for C 39 H 59 NO8[M+H] + : 670.4319; found: 670.4322.

[0048] Compound 8, 780 mg, yield: 72.3%. 1 1H NMR (400 MHz, DMSO-d6) δ 12.03 (s, 1H), 7.85 (t, J = 5.4 Hz, 1H), 5.43 (s, 1H), 4.42 (dd, J = 11.8, 4.4 Hz, 1H), 4.08–3.99 (m, 2H), 3.13–3.08 (m, 2H), 2.65–2.61 (m, 1H), 2.40 (s, 1H), 2.19 (t, J = 7.4 Hz, 2H), 2.10–2.03 (m, 4H), 2.00 (s, 3H), 1.84–1.74 (m, 4H), 1.71–1.62 (m, 6H), 1.59–1.41 (m, 4H), 1.37 (s, 3H), 1.33–1.23 (m, 3H), 1.20–1.17 (m, 2H), 1.11 (s, 3H), 1.06 (s, 3H), 1.04 (s, 3H), 0.97–0.87 (m, 2H), 0.82 (s, 6H), 0.75 (s, 3H). HR-MS (m / z) (ESI): calcd for C 40 H 61 NO8[M+H] + : 684.4475; found: 684.4514.

[0049] Example 5: Preparation of compounds 11-14

[0050] Compound 7 (0.269 mmol) or 8 (0.269 mmol) was dissolved in dry DMF solution, and TBTU (112 mg, 0.35 mmol) and Et3N (32 mg, 0.35 mmol) were added. The mixture was stirred for 10 minutes. Then, complex 9 (0.269 mmol) or complex 10 (0.269 mmol) was added, and the mixture was stirred overnight at 30°C in the dark. The reaction mixture was monitored by thin-layer chromatography. After the reaction was complete, dichloromethane (100 mL) was added to extract the mixture, and the organic phase was washed twice with saturated brine. The organic phase was dried and concentrated with anhydrous sodium sulfate to obtain the crude product. The crude product was purified by silica gel column chromatography, eluting with dichloromethane / methanol to give yellow solid products 11-14.

[0051] Compound 11, 134 mg, yield: 49.2%. 1 H NMR(600MHz,DMSO-d6)δ7.86(t,J=5.2Hz,1H),6.39–5.98(m,6H),5.44(s,1H),4.42(dd,J=11.7,4.1Hz,1 H),4.05(t,J=5.4Hz,2H),3.28(dd,J=11.2,5.6Hz,2H),2.64–2.62(m,1H),2.39(s,1H),2.20(t,J=7.4Hz, 2H),2.12–2.06(m,4H),2.00(s,3H),1.84–1.72(m,4H),1.69–1.60(m,4H),1.52–1.39(m,5H),1.36(s,3H ),1.33–1.15(m,4H),1.10(s,3H),1.06(s,3H),1.03(s,3H),0.96–0.87(m,2H),0.82(s,6H),0.74(s,3H). 13C NMR (100MHz, DMSO-d6) δ199.43,180.59,176.25,172.71,170.62,170.06,127.81,80. 14,65.40,62.98,61.31,54.16,48.35,45.32,44.00,43.38,38.33,38.11,38.03,37. 78,36.94,36.15,35.18,32.37,31.98,30.71,28.66,28.19,28.13,26.53,26.21,23. 69,23.46,22.16,21.46,18.77,17.39,17.06,16.63,15.65.HR-MS(m / z)(ESI):calcd for C 39 H 64 Cl3N3O8Pt[M+H] + :1003.3485; found:1003.3495.

[0052] Compound 12, 105 mg, yield: 38.5%. 1 HNMR(400MHz,DMSO-d6)δ7.87–7.68(t,J=5.2Hz,1H),6.31–5.99(m,6H),5.42(s,1H),4.42(dd,J=11.0,3.3Hz ,1H),4.11–3.97(m,2H),3.40–3.37(m,2H),3.17–3.03(m,2H),2.63(d,J=12.9Hz,1H),2.40(s,1H),2.21(t,J =7.1Hz,2H),2.09–2.02(m,4H),2.00(s,3H),1.84–1.71(m,4H),1.69–1.59(m,5H),1.53–1.40(m,4H),1.37(s ,3H),1.33–1.16(m,4H),1.11(s,3H),1.06(s,3H),1.04(s,3H),0.97–0.87(m,2H),0.82(s,6H),0.75(s,3H). 13C NMR(100MHz,DMSO-d6)δ199.42,180.57,176.23,172.42,170.62,170.11,127.78,80.1 3,65.40,62.36,61.30,54.15,48.42,45.33,43.97,43.41,38.33,38.03,37.81,36.95, 36.14,35.74,35.23,32.37,32.01,30.75,29.09,28.69,28.22,28.13,26.53,26.21,2 3.69,23.44,22.28,21.46,18.78,17.39,17.06,16.62,15.65.HR-MS(m / z)(ESI):calcd for C 30 H 66 Cl3N3O8Pt[M+H] + :1017.3641; found:1017.3604.

[0053] Compound 13.83 mg, yield: 28.0%. 1 H NMR(600MHz,DMSO-d6)δ8.43–8.24(m,3H),7.90(s,1H),7.66(s,1H),5.44(s,1H),4.43(dd,J=11.5,3.8Hz,1H),4.12–3.97 (m,2H),3.40–3.38(m,2H),3.29–3.28(m,2H),2.65–2.58(m,3H),2.40(s,1H),2.25(t,J=7.2Hz,2H),2.09–2.06(m,5H),2. 01(s,3H),1.83(d,J=11.6Hz,1H),1.72–1.67(m,4H),1.66–1.61(m,4H),1.57–1.48(m,4H),1.46–1.39(m,3H),1.37(s,3H) ,1.33–1.23(m,3H),1.21–1.13(m,3H),1.10(s,3H),1.07(s,3H),1.04(s,3H),0.97–0.88(m,2H),0.83(s,6H),0.75(s,3H). 13CNMR (100 MHz, DMSO-d6) δ 199.42, 180.78, 176.25, 172.45, 170.62, 170.05, 163.70, 127.81, 80.13, 65.40, 62.95, 61.96, 61.82, 61.31, 54.16, 48.34, 45.32, 43.99, 43.38, 38.33, 38.13, 38.03, 37.79, 36.94, 36.43, 35.00, 32.37, 31.97, 31.36, 31.04, 30.69, 28.64, 28.13, 26.53, 26.21, 24.03, 23.99, 23.68, 23.45, 21.92, 21.45, 18.76, 17.39, 17.05, 16.62, 15.64. HR-MS (m / z) (ESI): calcd for C 47 H 72 ClN3O 12 Pt[M+H] + : 1101.4531; found: 1101.4534.

[0054] Compound 14, 95 mg, yield: 31.7%. 1 H NMR (600 MHz, DMSO-d6) δ 8.41–8.32 (m, 3H), δ 7.82 (t, J=5.2 Hz, 1H), 7.70–7.60 (m, 1H), 5.42 (s, 1H), 4.42 (dd, J=11.6, 3.9 Hz, 1H), 4.08–4.00 (m, 2H), 3.46–3.43 (m, 2H), 3.14–3.05 (m, 2H), 2.64–2.57 (m, 3H), 2.40 (s, 1H), 2.25 (t, J=7.2 Hz, 2H), 2.10–2.04 (m, 5H), 2.00 (s, 3H), 1.82 (d, J=12.6 Hz, 1H), 1.77–1.70 (m, 4H), 1.68–1.61 (m, 4H), 1.53–1.47 (m, 6H), 1.43–1.41 (m, 2H), 1.39–1.34 (m, 5H), 1.18–1.13 (m, 5H), 1.11 (s, 3H), 1.06 (s, 3H), 1.04 (s, 3H), 0.97–0.88 (m, 2H), 0.82 (s, 6H), 0.75 (s, 3H). 13CNMR(100MHz,DMSO-d6)δ199.41,180.75,176.22,172.18,170.62,170.10,163.73,127.78,80.13, 65.40,62.31,61.98,61.80,61.30,54.15,48.42,45.32,43.97,43.40,38.33,38.03,37.80,36.94 ,36.46,35.74,35.06,32.37,32.00,31.35,31.04,30.74,29.04,28.67,28.20,28.13,26.53,26.2 1,24.01,23.68,23.43,22.03,21.45,18.77,17.39,17.05,16.62,15.64.HR-MS(m / z)(ESI):calcd for C 48 H 74 ClN3O 12 Pt[M+H] + :1115.4687; found:1115.4675.

[0055] Example 6: Preparation of Compound 16

[0056] Compound 2 (512 mg, 1.0 mmol) was dissolved in a dry DCM solution (10 mL), and EDCI (382 mg, 2.0 mmol), DMAP (182 mg, 1.5 mmol), and 3-buten-1-ol (104 mg, 1.5 mmol) were added. The mixture was stirred overnight at 30 °C. After the reaction was complete, the reaction mixture was extracted with dichloromethane (100 mL) and saturated brine (150 mL). The organic phase was dried over anhydrous Na₂SO₄ and concentrated under reduced pressure to give a crude product. The crude product was purified by silica gel column chromatography, eluting with petroleum ether / ethyl acetate, to give a white solid compound 16 (365 mg, yield: 64.7%). 1H NMR(600MHz, CDCl3)δ5.73(s,1H),4.51(dd,J=11.8,4.7Hz,1H),4.26–4.22(m,1H),4.19–4.19(m,1H),2.80–2.77(m,1 H),2.55–2.52(m,2H),2.35(s,1H),2.14(dd,J=13.6,3.3Hz,1H),2.04(s,3H),2.03–1.98(m,3H),1.96–1.93(m,1H),1. 84–1.79(m,1H),1.73–1.57(m,6H),1.48–1.38(m,4H),1.36(s,3H),1.33–1.28(m,1H),1.19–1.17(m,1H),1.16(s,3H), 1.15(s,3H),1.12(s,3H),1.07–1.00(m,2H),0.87(s,6H),0.80(s,3H),0.79(d,J=5.8Hz,1H).HR-MS(m / z)(ESI):calcd for C 36 H 52 O5[M+H] + :565.3893; found:565.3847.

[0057] Example 7: Preparation of Compound 18

[0058] Compound 16 (466 mg, 0.826 mmol) was dissolved in 6 mL of solution, and copper acetate monohydrate (33 mg, 0.165 mmol) was added. After stirring at room temperature for 5 minutes, compound 17 (271 mg, 1.239 mmol) was added, and the mixture was stirred for 5 minutes at the same temperature. Then, sodium ascorbate (58 mg, 0.330 mmol) was added, and the mixture was stirred overnight at 35 °C. After the reaction was complete, dichloromethane (100 mL) was added to the reaction mixture, and the mixture was washed with saturated brine. The organic phase was dried over anhydrous Na₂SO₄ and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography, eluting with petroleum ether / ethyl acetate, to give compound 18 (345 mg, yield: 53.4%) as a white solid. 1HNMR (600MHz, CDCl3) δ7.62(s,1H),5.51(s,1H),4.53(t,J=4.9Hz,2H),4.49(dd,J=11.8,4.6Hz,1H),4.42–4.36(m,2H),3.85( t,J=5.0Hz,2H),3.72–3.71(m,2H),3.68–3.64(m,2H),3.61–3.59(m,8H),3.07(t,J=6.6Hz,2H),2.79–2.75(m,1H),2.03(s,3H ),2.02–1.94(m,3H),1.88–1.77(m,2H),1.71–1.55(m,6H),1.46–1.36(m,3H),1.33(s,3H),1.31–1.24(m,3H),1.18(d,J=10.6 Hz,1H),1.14(s,3H),1.10(s,6H),1.05–0.97(m,2H),0.86(s,6H),0.80(d,J=5.8Hz,1H),0.77(s,3H).HR-MS(m / z)(ESI):calcd forC 44 H 69 N3O9[M+H] + :784.5112; found:784.5034.

[0059] Example 8: Preparation of Compound 19

[0060] Compound 18 (530 mg, 0.677 mmol) was dissolved in 10 mL of dry dichloromethane, and succinic anhydride (135 mg, 1.354 mmol) and DMAP (17 mg, 0.1354 mmol) were added. The mixture was refluxed and stirred overnight, and the reaction was monitored by thin-layer chromatography. After the reaction was complete, 100 mL of dichloromethane was added to the reaction mixture, and the mixture was washed with saturated brine. The organic phase was dried over anhydrous Na₂SO₄ and concentrated to give a crude product. The crude product was purified by silica gel column chromatography in a dichloromethane / methanol system to give a white solid compound 19 (460 mg, yield: 76.9%). 1H NMR(600MHz, CDCl3)δ7.59(s,1H),5.53(s,1H),4.53(t,J=4.3Hz,2H),4.50(dd,J=11.8,4.7Hz,1H),4.44–4.37(m,2H),4.26–4.24 (m,2H),3.87(t,J=4.3Hz,2H),3.67–3.66(m,2H),3.61–3.59(m,8H),3.09(t,J=6.7Hz,2H),2.79–2.75(m,1H),2.64(s,3H),2.34(s ,1H),2.04(s,3H),2.03–1.95(m,3H),1.89–1.80(m,2H),1.70–1.58(m,6H),1.46–1.37(m,3H),1.34(s,3H),1.32–1.24(m,4H),1.2 1–1.17(m,1H),1.14(s,3H),1.10(s,6H),1.06–0.98(m,2H),0.87(s,6H),0.84–0.79(m,1H),0.77(s,3H).HR-MS(m / z)(ESI):calcd for C 48 H 73 N3O 12 Na[M+H] + :906.5092; found:906.5035.

[0061] Compound 20 was synthesized by reacting compound 19 with compound 9, using the same synthetic method as compound 11. Compound 20, 73 mg, yield: 35.4%. 1H NMR(500MHz,DMSO-d6)δ7.91(s,1H),6.28–6.06(m,6H),5.31(s,1H),4.48(t,J=4.6Hz,2H),4.43(dd,J=11.7,3.9Hz,1H),4.39 –4.29(m,2H),4.16–4.08(m,2H),3.80–3.78(m,2H),3.61–3.60(m,2H),3.52–3.50(m,8H),2.97(t,J=6.2Hz,2H),2.64(d,J=13. 0Hz,1H),2.49–2.39(m,3H),2.10–2.04(m,1H),2.01(s,3H),1.97–1.95(m,1H),1.81–1.64(m,6H),1.54–1.38(m,4H),1.36(s, 3H),1.32–1.24(m,3H),1.15–1.12(m,3H),1.08(s,3H),1.07(s,3H),1.04(s,3H),0.96–0.88(m,3H),0.83(s,6H),0.72(s,3H). 13 CNMR(125MHz,DMSO-d6)δ199.40,179.39,176.18,172.77,170.61,170.04,143.44,127.71,123. 30,80.14,70.20,70.17,70.09,70.04,69.25,68.73,63.69,63.34,61.29,54.15,49.74,48.24,4 5.31,43.93,43.38,38.33,38.03,37.70,36.94,32.36,31.92,31.48,30.73,30.31,28.60,28.13 ,26.50,26.20,25.48,23.69,23.44,21.45,18.77,17.38,17.06,16.61.HR-MS(m / z)(ESI):calcd for C 48 H 78 Cl3N5O 12 Pt[M+H] + :1217.4439; found:1217.4475.

[0062] Compound 21 was synthesized by reacting compound 19 with compound 10, using the same synthetic method as compound 13. Compound 21, 89 mg, yield: 39.9%. 1H NMR(600MHz,CDCl3)δ8.43(s,1H),7.97(s,1H),7.62(s,1H),7.53(s,1H),6.72(s,1H),5.52(s,1H),4.56–4.52(m,2H),4.49(dd,J=11.7,4.5Hz,1H),4.43–4.36(m,2H),4.22–4.16(m,2H),3.87(t,J=4.9Hz,2H),3.70–2.66(m,2H),3.61–3.59(m,8H),3.46(q,J=7.0Hz,1H),3.07(t,J=6.7Hz,2H),3.04–2.94(m,2H),2.77–2.75(m,1H),2.55–2.49(m,4H),2.43–2.33(m,3H),2.03(s,3H),2.01–1.93(m,3H),1.87–1.77(m,2H),1.69–1.64(m,2H),1.61–1.55(m,6H),1.45–1.35(m,3H),1.33(s,3H),1.29–1.22(m,3H),1.20–1.18(m,2H),1.13(s,3H),1.09(s,6H),1.03–0.97(m,2H),0.86(s,6H),0.78(d,J=12.0Hz,1H),0.76(s,3H). 13 C NMR(150MHz,CDCl3)δ200.21,181.26,176.43,173.34,171.06,169.64,164.46,143.81,128.33,122.94,80.63,70.52,70.47,70.44,70.39,69.53,69.07,65.85,63.68,63.29,62.58,62.26,61.72,54.99,50.21,48.22,45.44,43.98,43.23,40.95,38.79,38.05,37.68,36.95,32.68,31.89,31.81,31.67,31.08,30.07,28.52,28.39,28.05,26.43,26.37,25.54,24.05,24.00,23.57,23.35,21.34,18.70,17.37,16.70,16.44,15.28.HR-MS(m / z)(ESI):calcd for C 56 H 86 ClN5O 16 Pt[M+H] +:1315.5484; found:1315.5540.

[0063] Example 9: In vitro antiproliferative activity test:

[0064] The in vitro antiproliferative activity of HepG-2 (hepatocellular carcinoma), Bel-7404 (hepatocellular carcinoma), MCF-7 (breast cancer), A549 (lung cancer), HL-7702 (normal human hepatocytes), and LO2 (normal human hepatocytes) was tested using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method.

[0065] 1. Experimental Methods

[0066] Cells were seeded at a density of 3000 cells / well in 96-well plates and incubated overnight at 37°C in a 5% CO2 atmosphere. The cells were then treated with different concentrations of the test compound for 72 h. After 72 h of incubation, freshly prepared MTT solution (10 μL / well, 5 mg / mL) was added to each well, and the cells were incubated under the same conditions for 4 h. Subsequently, the blue crystal particles were dissolved in DMSO (100 μL) instead of the supernatant, and the OD value was measured at 570 nm. The IC50 was calculated using SPSS software. 50 The values ​​and results are shown in Tables 1 and 2.

[0067] Table 1. Antiproliferative effects of compounds on human cancer cells and normal human hepatocytes.

[0068]

[0069] a Cisplatin. b Oxaliplatin. c Glycyrrhetinic acid. d Cisplatin: Glycyrrhetinic acid (1:1, n / n). e Cisplatin:glycyrrhetinic acid (1:1, n / n). Cells were treated three times with the compound to be tested at 37°C in the dark for 72 h; the results were determined by the MTT assay. f IC 50 Values, expressed as mean ± SD. Selective Index (SI) g =IC 50 (HL-7702) / IC 50 (HepG-2). f SI2, Selective Index = IC 50 (LO2) / IC 50 (Bel-7404).ND: Not calculated.

[0070] Table 2. Antiproliferative effects of representative compounds on cisplatin-resistant cells.

[0071]

[0072]

[0073] a Cisplatin. b Cisplatin:glycyrrhetinic acid (1:1, n / n). Cells were treated three times with the compound to be tested at 37°C in the dark for 72 h; the results were determined by the MTT assay. f IC 50 Values, expressed as mean ± SD. d Resistance Factor (RF) = IC 50 (HepG-2 / CDDP) / IC 50 (A549) d RF = IC 50 (A549 / CDDP) / IC 50 (A549).ND: Not calculated.

[0074] 2. Experimental Results

[0075] As shown in Table 1, the target compounds all exhibited good anti-proliferative activity against the tested tumor cell lines, and their anti-cancer activity was superior to that of the positive control drugs. Among them, compound 20 showed the best anti-proliferative activity, with an IC50 value of [missing value]. 50 The concentration ranged from 0.74 to 2.58 μM, and its inhibitory effect on HepG-2 cells was 7.04-fold and 3.77-fold higher than that of CDDP and CDDP / GA, respectively. Furthermore, compound 20 showed inhibitory effects on normal human hepatocytes HL-7702 (IC50). 50 =8.05μM) and LO2(IC 50 =7.15μM) has significantly lower toxicity than CDDP (IC). 50 =2.68 and IC 50 =3.39μM) and CDDP / GA (IC 50 =0.88 and IC 50 =0.93μM).

[0076] As shown in Table 2, compounds 11, 12, and 20 have IC50 values ​​for HepG-2 / CDDP and A549 / CDDP. 50 The values ​​were 4.18, 3.17, and 1.61 μM, respectively, compared to CDDP (IC). 50 =30.57 and IC 50 =35.63μM) showed better anti-proliferative effects. Furthermore, the RF values ​​at 11, 12, and 20 in HepG-2 / CDDP and A549 / CDDP were... d and RFe The values ​​were 2.07, 1.93, 2.18 and 1.75, 1.66 and 1.89, respectively, significantly lower than CDDP's 5.89 and 7.35. Notably, compound 20 showed better inhibitory effects on HepG-2 / CDDP and A549 / CDDP than the combination of CDDP and GA. These results indicate that compound 20 exhibits good anti-proliferative activity against both CDDP-sensitive and CDDP-resistant HepG-2 / CDDP and A549 / CDDP cells in vitro, and shows low toxicity to normal human hepatocytes (HL-7702 and LO2), demonstrating good tumor selectivity, warranting further investigation into its anti-tumor mechanism.

[0077] Example 10: In vivo anticancer experiment:

[0078] 1. Model Establishment

[0079] Twenty-five male Balb / c-nu athymic mice, 5 weeks old, were purchased from Hangzhou Qizhen Laboratory Animal Technology Co., Ltd., China, and housed under pathogen-free conditions. HepG-2 cells (1×10⁻⁶) were introduced. 7 ( / mouse) subcutaneously inoculated on the right side of mice to establish a HepG-2 xenograft model. Figure 1 As shown in Figures A through D, when the tumor volume reaches approximately 100 mm... 3 Mice were randomly divided into 5 groups: saline treatment group, CDDP (5.0 mg / kg), CDDP+GA (5+20 mg / kg), and 20 (5 or 16.5 mg / kg) treatment group. All mice received intravenous injections every 7 days for 21 consecutive days. Tumor volume was calculated using the formula 0.5 × length × width², and tumor volume and body weight were measured every 2 days for 21 consecutive days. The A549 xenograft model was established using the same method as the HepG-2 xenograft model.

[0080] 2. Experimental Results

[0081] like Figure 1 As shown in Figures A-D, compared with the saline-treated group, CDDP effectively inhibited the proliferation of HepG-2 xenografts, with an inhibition rate of 61.8%. Notably, when CDDP was combined with GA, the inhibition rate was 68.9%, indicating that combined treatment could improve therapeutic efficacy. Furthermore, compound 20 effectively inhibited the growth of HepG-2 xenografts in a dose-dependent manner, with inhibition rates of 54.7% and 72.9%, respectively. It can be seen that after high-dose treatment with compound 20, the inhibition rate was better than that of the CDDP and CDDP / GA treatment groups. Additionally, as... Figure 1As shown in Figures E-H, in the A549 xenograft experiment, compound 20 was also found to effectively inhibit the proliferation of A549 xenografts, with inhibition rates of 51.6% and 67.1%, exhibiting a dose-dependent effect. After treatment with a high dose of compound 20, its inhibition rate was superior to that of the CDDP (60.5%) and CDDP / GA (64.8%) treatment groups. Figure 1 As shown in Figures D and H, compared with the control group, mice treated with compound 20 did not show significant changes in body weight; however, mice in the CDDP group and the CDDP / GA administration group showed significant weight loss. Interestingly, compound 20 showed better inhibitory effects on the growth of HepG-2 xenografts than A549 xenografts, indicating that introducing GA, which targets the GA receptor, into the axial position of platinum (IV) can achieve liver targeting and reduce toxicity. These results suggest that introducing GA, which targets the GA receptor and has its own anticancer activity, into the axial position of platinum (IV) can achieve better in vivo antiproliferative activity and lower toxicity than CDDP, representing a promising strategy for treating liver cancer.

[0082] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A platinum (IV) prodrug using a glycyrrhetinic acid derivative as a ligand, characterized in that, The structural formulas of the platinum (IV) prodrugs are shown in Formula 11, Formula 12, Formula 13, Formula 14, Formula 20, or Formula 21: 。 2. A method for preparing a platinum(IV) prodrug using a glycyrrhetinic acid derivative as a ligand as described in claim 1, characterized in that, Includes the following steps: (1) React compound 1 with acetic anhydride to synthesize compound 2; (2) React compound 2 with 2-(boc-amino)ethyl bromide or 3-(boc-amino)propyl bromide to synthesize compound 3 or 4; (3) React compound 3 or 4 with TFA to synthesize compound 5 or 6; (4) React compound 5 or 6 with glutaric anhydride to give compound 7 or 8; (5) React compound 7 or 8 with complex 9 or 10 to obtain compounds 11-14; The synthesis route is shown below: 。 3. The method for preparing a platinum(IV) prodrug using a glycyrrhetinic acid derivative as a ligand according to claim 2, characterized in that: Includes the following steps: (1) Dissolve compound 1 in pyridine solution, then add acetic anhydride, stir overnight at room temperature to obtain compound 2, wherein the amount of compound used is in molar amounts, compound 1: acetic anhydride = 1: 2~4; (2) Dissolve compound 2 in DMF, and stir it overnight at 40~60 °C with 2-(boc-amino)ethyl bromide or 3-(boc-amino)propyl bromide in the presence of potassium carbonate to obtain compound 3 or 4. The amount of compound used is based on the molar ratio of compound 2: 2-(boc-amino)ethyl bromide or 3-(boc-amino)propyl bromide: potassium carbonate = 1 : 1~1.5 : 1.8~2.2; (3) Dissolve compound 3 or 4 in dry DCM, add TFA, and react at room temperature for 2-4 h to obtain compound 5 or 6, wherein the amount of compound used is in molar amounts, and the ratio of compound 3 or 4 to TFA is 1: 2-4. (4) Dissolve compound 5 or 6 in DMF, add triethylamine, then add glutaric anhydride, stir overnight at 50~80 °C to obtain compound 7 or 8, wherein the amount of compound used is by mole, and the ratio of compound 5 or 6 : triethylamine : glutaric anhydride = 1 : 1~3 : 2~4; (5) Dissolve compound 7 or 8 in DMF, add TBTU and triethylamine, then add complex 9 or 10, stir overnight at 20~40 °C to obtain compounds 11-14, wherein the amount of compounds used is in molar amounts, and the ratio of compound 7 or 8 : TBTU : triethylamine : complex 9 or 10 = 1 : 1~1.5 : 1~1.5 : 0.8~1.

2.

4. The method for preparing a platinum(IV) prodrug using a glycyrrhetinic acid derivative as a ligand according to claim 3, characterized in that: Steps (1) to (5) also include separation and purification steps.

5. A method for preparing a platinum(IV) prodrug using a glycyrrhetinic acid derivative as a ligand as described in claim 1, characterized in that, Includes the following steps: (1) React compound 2 with 15 to synthesize compound 16; (2) React compounds 16 and 17 to synthesize compound 18; (3) React compound 18 with succinic anhydride to synthesize compound 19; (4) React compound 19 with complex 9 or 10 to obtain compound 20-21; The synthesis route is shown below: 。 6. The method for preparing a platinum(IV) prodrug using a glycyrrhetinic acid derivative as a ligand according to claim 5, characterized in that: Includes the following steps: (1) Dissolve compound 2 in a dry DCM solution, add EDCI, DMAP and 3-butyn-1-ol, and stir overnight at 20~40 °C to obtain compound 16. The amounts of the compounds are calculated by molar ratio as follows: compound 2:EDCI:DMAP:3-butyn-1-ol = 1:1.8~2.2:1.2~1.8:1.2~1.8; (2) Dissolve compound 16 in methanol, add copper acetate, stir at room temperature for 3-5 minutes, then add compound 17, and then add sodium ascorbate. Stir at 30-40 °C overnight to obtain compound 18. The amount of compounds used is calculated by mole as follows: compound 16: copper acetate: compound 17: sodium ascorbate = 1 : 0.1~0.3 : 1.2~1.8 : 0.2~0.6; (3) Dissolve compound 18 in dry DCM, add succinic anhydride and DMAP, heat under reflux overnight to obtain compound 19, wherein the amount of compound used is in molar amounts, and the ratio of compound 18 : succinic anhydride : DMAP is 1 : 1.8~2.2 : 0.1~0.3; (4) Dissolve compound 19 in DMF, add TBTU and triethylamine, then add complex 9 or 10, stir overnight at 25~35 °C to obtain compound 20 or 21, wherein the amount of compound used is in molar amounts, and the ratio of compound 19 : TBTU : triethylamine : complex 9 or 10 = 1 : 1~1.5 : 1~1.5 : 0.8~1.

2.

7. The method for preparing a platinum(IV) prodrug using a glycyrrhetinic acid derivative as a ligand according to claim 6, characterized in that: Steps (1) to (5) also include separation and purification steps.

8. The use of the platinum(IV) prodrug with glycyrrhetinic acid derivative as a ligand as described in claim 1 in the preparation of a drug for treating liver cancer.

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