Ppd ring-opening derivatives, process for their preparation and use thereof

Abstract

The application discloses PPD open-loop derivatives, structural formula as shown in formula 11, 12, 13 or 14, or a pharmaceutically acceptable salt of the compound shown in formula 11, 12, 13 or 14. The application also discloses a preparation method of the PPD open-loop derivatives, and application of the PPD open-loop derivatives and the pharmaceutically acceptable salt thereof in preparation of a tumor drug resistance reversing agent / tumor drug sensitizer, or a tumor drug resistance reversing agent / tumor drug sensitizer containing a pharmaceutically acceptable carrier. The PPD open-loop derivative disclosed by the application has lower cytotoxicity and better tumor drug resistance reversing effect, and the effect is obviously better than that of a positive control drug. The PPD open-loop derivative disclosed by the application has strong development and application value.

Description

Technical Field

[0001] This invention relates to the fields of organic synthesis and medicinal chemistry, specifically to a novel class of PPD ring-opening derivatives, their preparation methods, and their applications in the pharmaceutical field. Background Technology

[0002] Malignant tumors severely impact human health. Chemotherapy is one of the effective treatments for malignant tumors, but the development of multidrug resistance (MDR) in tumors significantly reduces drug efficacy, greatly complicating tumor treatment. Overexpression of P-glycoprotein (P-gp) is one of the important reasons for multidrug resistance in tumors. P-gp inhibitors hold promise as key drugs for overcoming multidrug resistance in tumors. However, existing P-gp inhibitors suffer from low efficacy and high toxicity. Therefore, there is a need to explore P-gp inhibitors with novel structural types.

[0003] Ginseng is a commonly used traditional Chinese medicine. Ginsenosides are active chemical components extracted from ginseng, possessing various pharmacological activities such as antioxidant, anti-inflammatory, antibacterial, anticancer, and anti-myocardial ischemia effects. Among them, 20S-protopanaxadiol (PPD), as the main aglycone, is now often used as an adjuvant drug during the treatment of cancer patients. 20S-PPD is readily metabolized in vivo to form a furan ring structure, and its 3-hydroxyl group is also highly susceptible to hepatic metabolism. Therefore, if the furan ring side chain of PPD is selected, and a series of non-metabolizable derivatives are constructed through ring-opening of the A ring, it is possible to obtain novel P-gp inhibitors with high activity and low toxicity. Summary of the Invention

[0004] To design novel PPD derivatives with novel structures capable of reversing P-glycoprotein-mediated tumor MDR activity, and further to provide a drug and composition for treating tumors, this invention provides a series of derivatives having the structural features shown in formulas A, B, C, and D, and their pharmaceutically acceptable salts. The antitumor MDR activity of these compounds is discovered for the first time, and the compounds are synthesized for the first time.

[0005] The technical solution adopted in this invention is:

[0006] PPD ring-opening derivatives, having the structural formula shown in Formula 11, 12, 13 or 14, or pharmaceutically acceptable salts of compounds shown in Formula 11, 12, 13 or 14.

[0007]

[0008] Among them, R1, R2, R3, and R4 are each independently represented by R. x -KY-, where Y represents NH or O, K represents methylene or is absent, and R... xA C3-C10 heterocyclic or heteroaromatic group is either unsubstituted or substituted with one or more substituents. A heterocyclic or heteroaromatic group refers to a heterocyclic or heteroaromatic group containing one or both of the nitrogen (N) and oxygen (O) atoms in its ring. R x The substituents can be C1 to C10 alkyl or tert-butoxycarbonyl groups;

[0009] Preferred R x It is one of pyrazine, pyridine, aziridine, aziridine, thiophene, piperidine, furan, tetrahydrofuran, and thiazole.

[0010] Furthermore, preferably R1 represents 2-pyrazinylmethylamine-1-yl, 4-pyridinylmethanol-1-yl, 3-N-Boc-azacyclobutanol-1-yl, 3-azacyclobutanol-1-yl, 2-thiophenemethylamine-1-yl, 3-N-Boc-azacyclobutanol-1-yl or 4-N-Boc-piperidinol-1-yl; R2 represents 4-pyridinylmethanol-1-yl or 3-tetrahydrofuranol-1-yl; R3 represents 2-thiazolethanol-1-yl, 2-pyridinylmethanol-1-yl, 4-pyridinylmethanol-1-yl or 2-pyrazinylmethanol-1-yl; R4 represents furfuryl alcohol-1-yl, 2-thiazolethanol-1-yl, 2-pyridinylmethanol-1-yl, 4-pyridinylmethanol-1-yl or 2-pyrazinylmethanol-1-yl.

[0011] The PDD ring-opening derivatives shown in Formulas 11, 12, 13, or 14 of this invention are preferably one of the following:

[0012] (20S,24R)-epoxy-3,4-open-ring-3-(2-pyrazinemethylamine-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 11a);

[0013] (20S,24R)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 11b);

[0014] (20S,24R)-epoxy-3,4-open-ring-3-(3-N-Boc-azacyclobutanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 11c);

[0015] (20S,24R)-epoxy-3,4-open-ring-3-(3-azacyclobutanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 11d);

[0016] (20S,24R)-epoxy-3,4-open-ring-3-(3-N-Boc-azacyclobutaneamine-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 11f);

[0017] (20S,24R)-epoxy-3,4-open-ring-3-(4-N-Boc-piperidinol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 11g);

[0018] (20S,24S)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 12a);

[0019] (20S,24S)-epoxy-3,4-open-ring-3-(3-tetrahydrofuranol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (compound 12b);

[0020] (20S,24R)-epoxy-3,4-open-ring-3-(2-thiazol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 13a);

[0021] (20S,24R)-epoxy-3,4-open-ring-3-(2-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 13b);

[0022] (20S,24R)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 13c);

[0023] (20S,24R)-epoxy-3,4-open-ring-3-(4-pyrazinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 13d);

[0024] (20S,24S)-epoxy-3,4-open-ring-3-(furfuryl-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 14a);

[0025] (20S,24S)-epoxy-3,4-open-ring-3-(2-thiazol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 14b);

[0026] (20S,24S)-epoxy-3,4-open-ring-3-(2-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 14c);

[0027] (20S,24S)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 14d);

[0028] (20S,24S)-epoxy-3,4-open-ring-3-(2-pyrazinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (compound 14e).

[0029] The structural formulas of compounds 11a-11g, 12a-12b, 13a-13d, and 14a-14e are shown below:

[0030]

[0031]

[0032] More preferably, the PPD ring-opening derivative is a compound represented by formula 11a, 11b, 11c, 11d, 11f, 11g, 12a, 12b, 13a, 13b, 13c, 14a or 14d.

[0033] The present invention also provides the use of PPD ring-opening derivatives of Formula 11, 12, 13 or 14 and pharmaceutically acceptable salts thereof in the preparation of tumor resistance reversal agents / tumor drug sensitizers, or in the preparation of tumor resistance reversal agents / tumor drug sensitizers comprising a pharmaceutically acceptable carrier; furthermore, the PPD ring-opening derivatives of Formula 11, 12, 13 or 14 and pharmaceutically acceptable salts thereof can be used to prepare tumor resistance reversal agents / tumor drug sensitizers that overcome P-glycoprotein-mediated tumor resistance or to prepare tumor resistance reversal agents / tumor drug sensitizers comprising a pharmaceutically acceptable carrier.

[0034] Furthermore, in the aforementioned applications, the PPD ring-opening derivative is preferably a compound represented by formula 11a, 11b, 11c, 11d, 11f, 11g, 12a, 12b, 13a, 13b, 13c, 14a, or 14d.

[0035] The present invention also provides the use of PPD ring-opening derivatives of formula 11, 12, 13 or 14 and pharmaceutically acceptable salts thereof in the preparation of antitumor drugs, wherein the antitumor drugs include clinical antitumor drugs and tumor resistance reversal agents / tumor drug sensitizers, and the tumor resistance reversal agents / tumor drug sensitizers are PPD ring-opening derivatives of formula 11, 12, 13 or 14 and pharmaceutically acceptable salts thereof.

[0036] Furthermore, the tumor in question is breast cancer, colon cancer, cervical cancer, liver cancer, stomach cancer, or lung cancer.

[0037] The clinical antitumor drug mentioned is paclitaxel.

[0038] Furthermore, in the aforementioned applications, the PPD ring-opening derivative is preferably a compound represented by formula 11a, 11b, 11c, 11d, 11f, 11g, 12a, 12b, 13a, 13b, 13c, 14a, or 14d.

[0039] The present invention also provides the use of PPD ring-opening derivatives of formula 11, 12, 13 or 14 and pharmaceutically acceptable salts thereof in the preparation of adjuvant medicines or health products for cancer patients during chemotherapy, and the use is not limited to the treatment and prevention of multidrug-resistant cancer.

[0040] The pharmaceutically acceptable salts described in this invention refer to conventional acid addition salts that have the same pharmaceutical efficacy as the compound and are formed with suitable non-toxic organic or inorganic acids.

[0041] The present invention also provides a pharmaceutical composition for resisting multidrug resistance, the pharmaceutical composition comprising the PPD ring-opening derivatives shown in formula 11, 12, 13 or 14 and their pharmaceutically acceptable salts, and may also be formulated into pharmaceutical preparations such as tablets, capsules, powders, syrups, suspensions, injections, etc., by adding pharmaceutically acceptable carriers; and may also be added with commonly used pharmaceutical excipients such as sweeteners, diluents, and fillers.

[0042] Furthermore, in the pharmaceutical composition, the PPD ring-opening derivative is preferably of chemical formula 11a, 11b, 11c, 11d, 11f, 11g, 12a, 12b, 13a, 13b, 13c, 14a or 14d.

[0043] The pharmaceutical composition provided by this invention can be administered clinically via oral administration, injection, or other methods.

[0044] The clinical dosage of the pharmaceutical composition of the present invention is 0.01 mg to 1000 mg / day of the active ingredient, and may deviate from this range depending on the severity of the condition or the dosage form.

[0045] Furthermore, the present invention also provides a method for preparing the PPD ring-opening derivatives shown in formula 11, 12, 13 or 14, wherein the method is shown in the following reaction formula:

[0046]

[0047] The method includes the following steps:

[0048] (1) 24R-Pyxinol of Formula 1 or 24S-Pyxinol of Formula 2 are respectively fed with pyridine chlorochromate (PCC) at a molar ratio of 1:0.5 to 4 to carry out an oxidation reaction, thereby obtaining compound 3 or compound 4 respectively.

[0049] The reaction solvent in step (1) is an aprotic solvent, preferably dichloromethane (DCM) or tetrahydrofuran;

[0050] The reaction temperature for the oxidation reaction is -20℃ to 80℃; preferably -10℃ to 30℃, and more preferably room temperature.

[0051] The oxidation reaction takes 3 to 24 hours; the preferred reaction time is 3 to 12 hours. The reaction is typically monitored by TLC until completion.

[0052] After the reaction is completed, the reaction solution is post-processed to obtain compound 3 or compound 4. The post-processing method of the reaction solution is as follows: the reaction solution is filtered, vacuum concentrated, and then purified by silica gel column chromatography (SGCC) to obtain compound 3 or compound 4.

[0053] (2) Compound 3 or Compound 4 were reacted with m-chloroperoxybenzoic acid by Baeyer-Villiger reaction to prepare Compound 5 or Compound 6 respectively.

[0054] The molar ratio of compound 3 or compound 4 to m-chloroperoxybenzoic acid (m-CPBA) is 1:3 to 15.

[0055] Furthermore, the reaction solvent in step (2) is an aprotic solvent, preferably dichloromethane (DCM) or tetrahydrofuran;

[0056] The Baeyer-Villiger reaction is carried out at a temperature of 10°C to 40°C, preferably at room temperature, for a reaction time of 5 to 12 hours.

[0057] After the reaction is completed, the resulting reaction solution is post-processed to obtain compound 5 or compound 6. The post-processing method of the reaction solution is as follows: the reaction solution is stirred, filtered, vacuum concentrated, and then purified by silica gel column chromatography (SGCC) to obtain compound 5 or compound 6 respectively.

[0058] (3) Compound 5 or Compound 6 was reacted with p-toluenesulfonamide (P-TSA) in an acidic ring-opening reaction to prepare Compound 7 or Compound 8 respectively;

[0059] The molar ratio of compound 5 or compound 6 to p-toluenesulfonamide (P-TSA) is 1:3 to 9.

[0060] Furthermore, the reaction solvent in step (3) is an aprotic solvent, preferably dichloromethane (DCM) or tetrahydrofuran;

[0061] The reaction temperature for the acidic ring-opening reaction is -10℃ to 60℃, preferably 10℃ to 40℃, and more preferably room temperature; the reaction time is 5 to 18 hours.

[0062] After the reaction is completed, the resulting reaction solution is post-processed to obtain compound 7 or compound 8. The post-processing method of the reaction solution is as follows: the reaction solution is stirred, filtered, vacuum concentrated, and then purified by silica gel column chromatography (SGCC) to obtain compound 7 or compound 8 respectively.

[0063] (4) Compound 5 or Compound 6 undergoes an alkaline ring-opening reaction with potassium hydroxide (KOH) to prepare Compound 9 or Compound 10 respectively;

[0064] The molar ratio of compound 5 or compound 6 to potassium hydroxide is 1:2 to 10.

[0065] Furthermore, the reaction solvent in step (4) is an aprotic solvent, preferably an aqueous solution of tetrahydrofuran (THF / H2O); the volume ratio of tetrahydrofuran to water in the aqueous solution of tetrahydrofuran is preferably 10 to 20:1.

[0066] The reaction temperature for the alkaline ring-opening reaction is -10℃ to 40℃, preferably 10℃ to 40℃, and more preferably room temperature; the reaction time is 1 to 2 days, preferably 5 to 18 hours.

[0067] After the reaction is completed, the resulting reaction solution is post-processed to obtain compound 9 or compound 10. The post-processing method of the reaction solution is as follows: the solvent of the reaction solution is evaporated under vacuum, and the concentrated sample is purified by silica gel column chromatography to obtain compound 9 or compound 10 respectively.

[0068] (5) Compound 7, Compound 8, Compound 9 or Compound 10 are reacted with amino-containing heterocyclic compounds (R1-NH2, R2-NH2, R3-NH2, R4-NH2) or hydroxyl-containing heterocyclic compounds (R1-OH, R2-OH, R3-OH, R4-OH) to prepare PPD ring-opening derivatives of formula 11, 12, 13 or 14 respectively by amide reaction or esterification reaction.

[0069] The molar ratio of compound 7, compound 8, compound 9 or compound 10 to the amino-containing heterocyclic compound or the hydroxyl-containing heterocyclic compound is 1:1.2 to 10;

[0070] Furthermore, the catalysts for the amide reaction are HBTU (benzotriazole-N,N,N,N-tetramethylurea hexafluorophosphate) and triethylamine, and the molar ratio of compounds 7, 8, 9, or 10 to HBTU and triethylamine is 1:1.3–5:2–10.

[0071] Furthermore, the catalysts for the esterification reaction are EDCI and DMAP, and the molar ratio of compound 7, compound 8, compound 9 or compound 10 to EDCI and DMAP is 1:2 to 5:0.1 to 1.

[0072] Furthermore, the reaction solvent in step (5) is an aprotic solvent, preferably N,N-dimethylformamide or dichloromethane (DCM);

[0073] The reaction temperature for the amide reaction or esterification reaction is -10℃ to 40℃, preferably 5℃ to 40℃, and more preferably room temperature; the reaction time is 0.5 to 16 hours.

[0074] After the reaction is completed, the resulting reaction solution is post-processed to obtain PPD ring-opening derivatives represented by formula 11, 12, 13 or 14, respectively. The post-processing method of the reaction solution is as follows: the reaction solution is quenched by adding water, extracted with ethyl acetate, the organic phase is washed, dried and then filtered and concentrated, and the concentrated sample is purified by silica gel column chromatography to obtain PPD ring-opening derivatives represented by formula 11, 12, 13 or 14, respectively.

[0075] The present invention has the following advantages over the prior art:

[0076] 1. The PPD ring-opening derivatives represented by formulas (11a-11g), (12a-12b), (13a-13d), and (14a-14e) of this invention are synthesized for the first time, and their anti-tumor MDR activity is discovered for the first time compared to their respective parent compounds 7-10.

[0077] 2. The PPD derivatives represented by formulas (11a-11g), (12a-12b), (13a-13d), and (14a-14e) of this invention exhibit lower cytotoxicity than verapamil (Vrp), a classic P-glycoprotein inhibitor with relatively low toxicity. For example, at a drug concentration of 30 μM, the survival rate of drug-resistant tumor cells KBV treated with Vrp was approximately 40%, while compounds 11a-11g, 12a-12b, 13a-13d, and 14a-14e showed no cytotoxicity, with survival rates all exceeding 80%.

[0078] 3. The compounds of this invention exhibit better tumor resistance reversal activity. The PPD derivatives represented by formulas (11a-11g), (12a-12b), (13a-13d), and (14a-14e) of this invention, compared with saponin PPD and parent compounds 7-10, possess better tumor resistance reversal ability and activity in inhibiting P-glycoprotein function. For example, the clinically commonly used drug paclitaxel shows no cytotoxicity to the tumor-resistant cell line KBV at 100 nM. Even with the combined addition of 10 μM concentrations of saponin PPD and parent compounds 7-10, no cytotoxicity was observed, indicating that at this concentration, these compounds failed to increase the sensitivity of paclitaxel-resistant tumor cells KBV to paclitaxel. When compounds 11a, 11b, 11c, 11d, 11f, 11g, 12a, 12b, 13a, 13b, 13c, 14a, and 14d were added in combination, the survival rate of KBV cells was significantly reduced, indicating that they significantly improved the sensitivity of paclitaxel-resistant tumor cells (KBV) to paclitaxel, i.e., demonstrating a tumor resistance reversal effect, and the effect was significantly better than the positive control drug verapamil (Vrp). The PPD ring-opening derivative of this invention has strong development and application value. Detailed Implementation

[0079] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0080] Example 1: (20S,24R)-epoxy-3,4-open-ring-3-(2-pyrazinemethylamine-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (11a);

[0081] Using protopanaxadiol (20S-PPD) (100 mg, 0.217 mmol) as the raw material, it was dissolved in anhydrous dichloromethane (2.17 mL), and an oxidative cyclization reaction was carried out using m-CPBA (54.933 mg, 0.318 mmol). After stirring at room temperature for 12 h, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediates 1 and 2. Intermediate 1 (821 mg, 1.72 mmol) was dissolved in anhydrous dichloromethane (20 mL), and pyridine chlorochromate (389 mg, 1.80 mmol) was added. After stirring at room temperature for 12 h, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 3. Compound 3 (26 mg, 0.054 mmol) was dissolved in 0.5 mL of dichloromethane, and m-CPBA (101 mg, 0.438 mmol) was added. After stirring at room temperature overnight, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 5. Compound 5 (22 mg, 0.045 mmol) was dissolved in anhydrous dichloromethane (0.9 mL), and P-TSA (68.3 mg, 0.359 mmol) was added. After stirring at room temperature for 12 h, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 7. Compound 7 (250 mg, 0.510 mmol) and 2-aminomethylpyrazine (0.612 mmol) were dissolved in anhydrous DCM (10 mL), and HBTU (240 mg, 0.045 mmol) was added. 76 mmol) and Et3N (200 μL) were stirred at room temperature for about 5 minutes, then an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed with saturated NaHCO3 solution and saturated NaCl aqueous solution in sequence. The organic layer was then dried with Na2SO4, concentrated, and obtained by column chromatography to obtain the target compound 11a [(20S,24R)-epoxy-3,4-open-ring-3-(2-pyrazinemethylamine-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol].

[0082] 1H NMR(400MHz, CDCl3)δ8.61(d,J=1.4Hz,1H),8.56–8.48(m,2H),4.87(t,J=1.8Hz,1H),4.71(d ,J=2.2Hz,1H),4.62(dd,J=16.8,5.1Hz,1H),4.56(dd,J=16.7,5.0Hz,1H),3.86(dd,J=8.7,6 .6Hz,1H),3.54(td,J=10.5,4.4Hz,1H),2.41–2.29(m,1H),2.25–2.10(m,2H),2.09–1.13(m, 19H),1.76(d,J=1.2Hz,3H),1.27(s,6H),1.10(s,3H),1.03(s,3H),0.92(s,3H),0.87(s,3H).

[0083] Example 2: (20S,24R)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (11b);

[0084] Under argon protection, compound 7 (250 mg, 0.510 mmol) from Example 1 and 4-pyridinemethanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C. The mixture was stirred at room temperature for about 30 minutes, and then an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4 and concentrated. The concentrated sample was purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, the target compound 11b [(20S,24R)-epoxy-3,4-open-ring-3-(4-pyridinemethanol-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol] was obtained by column chromatography.

[0085] 1H NMR (400MHz, CDCl3) δ8.64–8.58(m,2H),7.27–7.22(m,2H),5.10(s,2H),4.85(t,J=1.8Hz,1H),4.6 7(d,J=2.2Hz,1H),3.86(dd,J=8.7,6.5Hz,1H),3.54(td,J=10.5,4.5Hz,1H),2.43(ddd,J=15.8,10. 1,6.1Hz,1H),2.29(ddd,J=15.1,11.2,7.2Hz,1H),2.20(ddd,J=10.9,9.0,3.7Hz,1H),2.11–0.83( m,19H),1.73(s,3H),1.28(s,3H),1.27(s,3H),1.10(s,3H),1.03(s,3H),0.92(s,3H),0.87(s,3H).

[0086] Example 3: (20S,24R)-epoxy-3,4-open-ring-3-(3-N-Boc-azacyclobutanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol(11c);

[0087] Under argon protection, intermediate 7 (250 mg, 0.510 mmol) from Example 1 and N-Boc-3-hydroxyazacyclobutane (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for approximately 30 minutes. Then, an appropriate amount of deionized water was added for quenching, and the organic layer was extracted with EA. The organic layer was washed sequentially with saturated NaHCO3 solution and saturated NaCl aqueous solution, then dried with Na2SO4 and concentrated. The concentrated sample was purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, the target compound 11c[(20S,24R)-epoxy-3,4-open-ring-3-(3-N-Boc-azacyclobutanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol] was obtained by column chromatography.

[0088] 1H NMR (400MHz, CDCl3) δ5.10(tt,J=6.8,4.3Hz,1H),4.86(t,J=1.8Hz,1H),4.66(d,J=1.4Hz,1H),4. 21(ddt,J=10.0,6.8,1.2Hz,2H),3.90–3.87(m,1H),3.87–3.82(m,2H),3.53(td,J=10.6,4.5Hz,1 H),2.36(ddd,J=15.7,10.3,6.0Hz,1H),2.26–2.14(m,2H),2.11–0.83(m,19H),1.73(d,J=0.4Hz, 3H),,1.45(s,9H),,1.28(s,3H),1.28(s,3H),1.10(s,3H),1.03(s,3H),0.92(s,3H),0.86(s,3H).

[0089] Example 4: (20S,24R)-epoxy-3,4-open-ring-3-(3-azacyclobutanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (11d);

[0090] Under argon protection, intermediate product 7 (250 mg, 0.510 mmol) from Example 1 and aziridine-3-ol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C. The mixture was stirred at room temperature for about 30 minutes, and then an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4 and concentrated. The concentrated sample was purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, the target compound 11d[(20S,24R)-epoxy-3,4-open-ring-3-(3-aziridine-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol] was obtained by column chromatography.

[0091] 1H NMR (400MHz, CDCl3) δ5.30 (s, 1H), 4.85 (t, J = 1.8Hz, 1H), 4.65 (d, J = 2.1Hz, 1H ),4.55–4.02(m,4H),3.86(t,J=7.7Hz,1H),3.56(t,J=7.9Hz,1H),2.43–2.34( m,1H),2.31–2.17(m,2H),2.09–1.79(m,8H),1.72(s,3H),1.71–0.88(m,11H), 1.28(s,3H),1.27(s,3H),1.12(s,3H),1.03(s,3H),0.93(s,3H),0.87(s,3H).

[0092] Example 5: (20S,24R)-epoxy-3,4-open-ring-3-(2-thienylmethylamine-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol(11e);

[0093] Under argon protection, intermediate product 7 (250 mg, 0.510 mmol) from Example 1 and 2-thiophene methylamine (0.612 mmol) were dissolved in anhydrous DCM (10 mL), HBTU (240 mg, 0.76 mmol) and Et3N (200 μL) were added, and the mixture was stirred at room temperature for about 5 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed with saturated NaHCO3 solution and saturated NaCl aqueous solution in sequence. The organic layer was then dried with Na2SO4, concentrated, and obtained by column chromatography to obtain the target compound 11e [(20S,24R)-epoxy-3,4-open-ring-3-(2-thiophene methylamine-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol].

[0094] 1 H NMR(400MHz, CDCl3)δ7.22(dd,J=4.9,1.5Hz,1H),6.99–6.91(m,2H),4.87(t,J=1.8Hz,1H), 4.70(d,J=2.1Hz,1H),4.61(dd,J=15.3,5.7Hz,1H),4.55(dd,J=15.2,5.5Hz,1H),3.85(dd,J =8.7,6.5Hz,1H),3.52(td,J=10.5,4.4Hz,1H),2.36–2.24(m,1H),2.24–2.16(m,1H),2.11– 1.12(m,20H),1.75(s,3H),1.27(s,6H),1.10(s,3H),1.02(s,3H),0.90(s,3H),0.86(s,3H).

[0095] Example 6: (20S,24R)-epoxy-3,4-open-ring-3-(3-N-Boc-azacyclobutaneamine-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (11f);

[0096] Under argon protection, intermediate product 7 (250 mg, 0.510 mmol) from Example 1 and N-Boc-3-hydroxyazacyclobutane (0.612 mmol) were dissolved in anhydrous DCM (10 mL), HBTU (240 mg, 0.76 mmol) and Et3N (200 μL) were added, and the mixture was stirred at room temperature for about 5 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed with saturated NaHCO3 solution and saturated NaCl aqueous solution in sequence. The organic layer was then dried with Na2SO4, concentrated, and obtained by column chromatography to obtain the target compound 11f[(20S,24R)-epoxy-3,4-open-ring-3-(3-N-Boc-azacyclobutaneamine-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol].

[0097] 1 H NMR(400MHz, CDCl3) δ4.88(t,J=1.5Hz,1H),4.70(d,J=2.2Hz,1H),4.64–4.50( m,1H),4.27(dt,J=37.5,8.5Hz,2H),3.86(dd,J=8.7,6.6Hz,1H),3.72(dd,J=9 .3,5.3Hz,2H),3.55(td,J=10.5,4.4Hz,1H),2.32–1.13(m,22H),1.76(s,3H), 1.44(s,9H),1.28(s,6H),1.11(s,3H),1.02(s,3H),0.91(s,3H),0.86(s,3H).

[0098] Example 7: (20S,24R)-epoxy-3,4-open-ring-3-(4-N-Boc-piperidinol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (11g);

[0099] Under argon protection, intermediate product 7 (250 mg, 0.510 mmol) from Example 1 and N-Boc-3-hydroxypiperidine (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C. The mixture was stirred at room temperature for about 30 minutes, and then an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4 and concentrated. The concentrated sample was purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, the target compound 11 g [(20S,24R)-epoxy-3,4-open-ring-3-(4-N-Boc-piperidinol-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol] was obtained by column chromatography.

[0100] 1 H NMR (400MHz, CDCl3) δ4.94–4.83(m,2H),4.68–4.65(m,1H),3.86(dd,J=8.7,6.6Hz ,1H),3.71(dd,J=13.3,6.5Hz,2H),3.54(td,J=10.6,4.4Hz,1H),3.25–3.13(m,2H ),2.33(ddd,J=15.6,10.4,5.6Hz,1H),2.24–1.30(m,25H),1.73(s,3H),1.46(s,9 H),1.28(s,3H),1.27(s,3H),1.10(s,3H),1.02(s,3H),0.92(s,3H),0.85(s,3H).

[0101] Example 8: (20S,24S)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol (12a);

[0102] Using protopanaxadiol (20S-PPD) (100 mg, 0.217 mmol) as a raw material, it was dissolved in anhydrous dichloromethane (2.17 mL), and an oxidative cyclization reaction was carried out using m-CPBA (54.933 mg, 0.318 mmol). After stirring at room temperature for 12 h, the mixture was filtered, concentrated under vacuum, and then 24S-Pyxinol was obtained by silica gel column chromatography (SGCC). 24S-Pyxinol (821 mg, 1.72 mmol) was dissolved in anhydrous dichloromethane (20 mL), and pyridine chlorochromate (389 mg, 1.80 mmol) was added. After stirring at room temperature for 12 h, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 4. Compound 4 (26 mg, 0.054 mmol) was dissolved in 0.5 mL of dichloromethane, and m-CPBA (101 mg, 0.438 mmol) was added. After stirring at room temperature overnight, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 6. Compound 6 (22 mg, 0.045 mmol) was dissolved in anhydrous dichloromethane (0.9 mL), and P-TSA (68.3 mg, 0.359 mmol) was added. After stirring at room temperature for 12 h, the mixture was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 8. Under argon protection, compound 8 (250 mg, 0.510 mmol) and 4-pyridinemethanol (0.612 mmol) were dissolved in anhydrous DCM (1 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C. The mixture was stirred at room temperature for about 30 minutes, and then quenched with an appropriate amount of deionized water. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and obtained by column chromatography to obtain the target compound 12a [(20S,24S)-epoxy-3,4-open-ring-3-(4-pyridinemethanol-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol].

[0103] 1H NMR (400MHz, CDCl3) δ8.65 (dd, J=4.4, 1.6Hz, 2H), 7.31 (dd, J=4.5, 1.6Hz, 2H), 5.12 (s,2H),4.86(t,J=1.8Hz,1H),4.67(d,J=1.3Hz,1H),3.88(dd,J=10.9,5.3Hz,1H),3 .55(td,J=10.4,4.7Hz,1H),2.51–2.21(m,3H),2.14–0.83(m,19H),1.74(d,J=0.3Hz ,3H),1.28(s,3H),1.23(s,3H),1.11(s,3H),1.06(s,3H),0.93(s,3H),0.91(s,3H).

[0104] Example 9: (20S,24S)-epoxy-3,4-open-ring-3-(3-tetrahydrofuranol-1-yl)carbonyl-4(28)-ene-dammarane-12β,25-diol(12b);

[0105] Under argon protection, intermediate product 8 (250 mg, 0.510 mmol) from Example 14 and 3-hydroxytetrahydrofuran (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C. The mixture was stirred at room temperature for about 30 minutes, and then an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and obtained by column chromatography to obtain the target compound 12b [(20S,24S)-epoxy-3,4-open-ring-3-(3-tetrahydrofuranol-1-yl)carbonyl-4(28)-en-dammarane-12β,25-diol].

[0106] 1 H NMR (400MHz, CDCl3) δ5.27(ddt,J=6.6,5.0,1.7Hz,1H),4.86(t,J=1.8Hz,1H),4.67(d,J=1.8Hz,1H),3.95–3.75(m,5H),3.55(td,J =10.4,4.6Hz,1H),2.42–0.83(m,24H),1.74(s,3H),1.28(s,3H),1.24(s,3H),1.11(s,3H),1.06(s,3H),0.93(s,3H),0.89(s,3H).

[0107] Example 10: (20S,24R)-epoxy-3,4-open-ring-3-(2-thiazol-methanol-1-yl)carbonyl-dammarane-4,12β,25-triol (13a);

[0108] Intermediate product 5 (200 mg, 0.41 mmol) synthesized in Example 1 was dissolved in a stirred solution (14 mL, 20:1, v / v) of THF / H2O, and KOH (110 mg, 2.03 mmol) was slowly added. After stirring at room temperature for 12 h, the solution was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate compound 9. Under argon protection, compound 9 (250 mg, 0.510 mmol) and 2-thiazolyl methanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL), and EDCI (250 mg, 1.31 mmol) was added at 0 °C. The sample was stirred at room temperature for about 30 minutes with 10 mg of DMAP (10 mg, 0.08 mmol) and DMAP (10 mg, 0.08 mmol). Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed with saturated NaHCO3 solution and saturated NaCl aqueous solution in sequence. The organic layer was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 13a [(20S,24R)-epoxy-3,4-open-ring-3-(2-thiazol-methanol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0109] 1 H NMR (400MHz, CDCl3) δ7.77 (dd, J=10.6, 3.1Hz, 1H), 7.34 (dd, J=14.6, 3.1Hz, 1H), 5.38 (s ,2H),3.85(dd,J=8.8,6.5Hz,1H),3.50(td,J=10.5,4.3Hz,1H),2.57(tdd,J=15.2,10.6, 4.4Hz,2H),2.27(ddd,J=18.3,9.7,4.9Hz,1H),2.22–2.15(m,1H),2.12–0.84(m,18H),1. 27(s,6H),1.27(s,3H),1.24(s,3H),1.10(s,3H),1.02(s,3H),1.00(s,3H),0.88(s,3H).

[0110] Example 11: (20S,24R)-epoxy-3,4-open-ring-3-(2-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (13b);

[0111] Under argon protection, intermediate product 9 (250 mg, 0.510 mmol) from Example 10 and 2-pyridinylmethanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then concentrated with Na2SO4. The concentrated sample was purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 13b [(20S,24R)-epoxy-3,4-open-ring-3-(2-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0112] 1 H NMR (400MHz, CDCl3) δ8.60(d,J=4.5Hz,1H),7.73(td,J=8.0,1.9Hz,1H),7.37(d,J=7.8Hz,1H),7.2 4(dd,J=7.6,5.0Hz,1H),5.23(s,2H),3.85(dd,J=8.7,6.5Hz,1H),3.51(td,J=10.5,4.5Hz,1H),2.7 1–2.51(m,2H),2.30(ddd,J=15.4,11.3,6.4Hz,1H),2.19(ddd,J=10.9,9.0,3.8Hz,1H),2.11–0.83( m,18H),1.28(s,3H),1.27(s,6H),1.24(s,3H),1.10(s,3H),1.03(s,3H),1.00(s,3H),0.88(s,3H).

[0113] Example 12: (20S,24R)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (13c);

[0114] Under argon protection, intermediate product 9 (250 mg, 0.510 mmol) from Example 10 and 4-pyridinylmethanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 13c [(20S,24R)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0115] 1 H NMR (400MHz, CDCl3) δ8.70(d,J=5.5Hz,2H),7.39(d,J=5.9Hz,2H),5.14(d,J=2. 2Hz, 2H), 3.86 (dd, J=8.7, 6.6Hz, 1H), 3.52 (td, J=10.5, 4.4Hz, 1H), 2.57 (td, J=1 3.5,4.4Hz,2H),2.35–2.15(m,2H),2.11–0.83(m,18H),1.28(s,3H),1.27(s,3H) ),1.27(s,3H),1.25(s,3H),1.10(s,3H),1.03(s,3H),1.01(s,3H),0.90(s,3H).

[0116] Example 13: (20S,24R)-epoxy-3,4-open-ring-3-(4-pyrazinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (13d);

[0117] Under argon protection, intermediate product 9 (250 mg, 0.510 mmol) from Example 10 and 4-pyrazinol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 13d [(20S,24R)-epoxy-3,4-open-ring-3-(4-pyrazinol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0118] 1 H NMR (400MHz, CDCl3) δ8.67(s,1H),8.56(dt,J=10.3,2.3Hz,2H),5.26(d,J=3.3Hz,2H ),3.85(dd,J=8.6,6.5Hz,1H),3.51(td,J=10.6,4.4Hz,1H),2.67–2.52(m,2H),2.30( ddd,J=15.2,11.2,6.1Hz,1H),2.19(tt,J=9.2,4.0Hz,1H),2.12–0.83(m,18H),1.27( s,3H),1.27(s,6H),1.25(s,3H),1.10(s,3H),1.03(s,3H),1.00(s,3H),0.89(s,3H).

[0119] Example 14: (20S,24S)-epoxy-3,4-open-ring-3-(furfuryl-1-yl)carbonyl-dammarane-4-12β,25-triol (14a);

[0120] Intermediate 6 (200 mg, 0.41 mmol) synthesized in Example 8 was dissolved in a stirred solution (14 mL, 20:1, v / v) of THF / H2O, and KOH (110 mg, 2.04 mmol) was slowly added. After stirring at room temperature for 12 h, the solution was filtered, concentrated under vacuum, and then subjected to silica gel column chromatography (SGCC) to obtain intermediate 10. Under argon protection, compound 10 (250 mg, 0.510 mmol) and furfuryl alcohol (0.612 mmol) were dissolved in anhydrous DCM (10 mL), and EDCI (250 mg, 1.31 mmol) was added at 0 °C. The sample was stirred with DMAP (10 mg, 0.08 mmol) at room temperature for about 30 minutes, then quenched with an appropriate amount of deionized water. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The sample was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 14a [(20S,24S)-epoxy-3,4-open-ring-3-(furfuryl-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0121] 1 H NMR (400MHz, CDCl3) δ7.42 (dd, J=1.9, 0.8Hz, 1H), 6.40 (dd, J=3.3, 0.8Hz, 1H), 6.35 (dd, J=3.3, 1.8Hz, 1H),5.05(d,J=7.9Hz,2H),3.88(dd,J=10.9,5.4Hz,1H),3.50(td,J=10.4,4.7Hz,1H),2.58(ddd,J=14 .9,10.3,4.8Hz,1H),2.47(ddd,J=15.3,10.2,4.8Hz,1H),2.24(tdd,J=10.3,6.9,5.1Hz,2H),2.12–0. 85(m,18H),1.27(s,6H),1.24(s,3H),1.23(s,3H),1.10(s,3H),1.05(s,3H),1.02(s,3H),0.87(s,3H).

[0122] Example 15: (20S,24S)-epoxy-3,4-open-ring-3-(2-thiazol-methanol-1-yl)carbonyl-dammarane-4,12β,25-triol (14b);

[0123] Under argon protection, intermediate product 10 (250 mg, 0.510 mmol) synthesized in Example 14 and 2-thiazolylmethanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 14b [(20S,24S)-epoxy-3,4-open-ring-3-(2-thiazolylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0124] 1 H NMR(400MHz, CDCl3) δ7.79(d,J=3.3Hz,1H),7.36(d,J=3.2Hz,1H),5.39(s,2 H),3.88(dd,J=10.8,5.4Hz,1H),3.53(td,J=10.4,4.6Hz,1H),2.58(tdd,J=1 5.3,10.6,4.5Hz,2H),2.37–2.22(m,2H),2.11–0.83(m,18H),1.28(s,6H),1 .25(s,3H),1.23(s,3H),1.11(s,3H),1.06(s,3H),1.03(s,3H),0.90(s,3H).

[0125] Example 16: (20S,24S)-epoxy-3,4-open-ring-3-(2-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (14c);

[0126] Under argon protection, intermediate product 10 (250 mg, 0.510 mmol) synthesized in Example 14 and 2-pyridinylmethanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 14c [(20S,24S)-epoxy-3,4-open-ring-3-(2-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0127] 1 H NMR(400MHz, CDCl3) δ8.60(d,J=4.9Hz,1H),7.76–7.67(m,1H),7.36(d,J=7.8Hz,1H),7.24(dd,J =7.3,4.9Hz,1H),5.23(s,2H),3.88(dd,J=10.8,5.4Hz,1H),3.53(td,J=10.4,4.6Hz,1H),2.70–2 .52(m,2H),2.34(ddd,J=18.3,8.4,4.5Hz,1H),2.25(ddd,J=13.8,8.6,3.5Hz,1H),2.12–0.83(m, 18H),1.28(s,6H),1.25(s,3H),1.23(s,3H),1.11(s,3H),1.06(s,3H),1.04(s,3H),0.90(s,3H).

[0128] Example 17: (20S,24S)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (14d);

[0129] Under argon protection, intermediate product 10 (250 mg, 0.510 mmol) synthesized in Example 14 and 4-pyridinylmethanol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 14d [(20S,24S)-epoxy-3,4-open-ring-3-(4-pyridinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0130] 1 H NMR (400MHz, CDCl3) δ8.62(d,J=5.1Hz,2H),7.29(d,J=5.4Hz,2H),5.12(s, 2H),3.88(dd,J=10.9,5.3Hz,1H),3.54(td,J=10.4,4.6Hz,1H),2.64–2.52( m,2H),2.37–2.22(m,2H),2.12–0.83(m,18H),1.28(s,3H),1.27(s,3H),1. 25(s,3H),1.24(s,3H),1.11(s,3H),1.06(s,3H),1.04(s,3H),0.91(s,3H).

[0131] Example 18: (20S,24S)-epoxy-3,4-open-ring-3-(2-pyrazinylmethanol-1-yl)carbonyl-dammarane-4,12β,25-triol (14e);

[0132] Under argon protection, intermediate product 10 (250 mg, 0.510 mmol) synthesized in Example 14 and 2-pyrazinol (0.612 mmol) were dissolved in anhydrous DCM (10 mL). EDCI (250 mg, 1.31 mmol) and DMAP (10 mg, 0.08 mmol) were added at 0 °C, and the mixture was stirred at room temperature for about 30 minutes. Then, an appropriate amount of deionized water was added for quenching. The organic layer was extracted with EA and washed successively with saturated NaHCO3 solution and saturated NaCl aqueous solution. The mixture was then dried with Na2SO4, concentrated, and purified by silica gel column chromatography. Based on the adsorption properties of the target product on silica gel, a suitable eluent was selected for purification to obtain the target compound 14e[(20S,24S)-epoxy-3,4-open-ring-3-(2-pyrazinol-1-yl)carbonyl-dammarane-4,12β,25-triol].

[0133] 1 H NMR (400MHz, CDCl3) δ8.67 (d, J=1.5Hz, 1H), 8.56 (dd, J=2.5, 1.5Hz, 1H), 8.54 (d, J=2.6Hz,1H),5.26(d,J=3.1Hz,2H),3.88(dd,J=10.9,5.4Hz,1H),3.53(td,J=10. 4,4.6Hz,1H),2.68–2.53(m,2H),2.39–2.20(m,2H),2.14–0.83(m,18H),1.28(s,6 H),1.25(s,3H),1.23(s,3H),1.10(s,3H),1.06(s,3H),1.04(s,3H),0.90(s,3H).

[0134] Example 19: Cytotoxicity evaluation of PPD derivatives

[0135] Experimental methods:

[0136] (1) Cell plating: KBV cells in logarithmic growth phase and in good condition were digested and counted, according to a 2.5×10⁻⁶ m² / h²· ... 3 / wells were seeded into 96-well plates and cultured in a 37°C, 5% CO2 cell incubator;

[0137] (2) Cell drug administration: After cells adhered to the plate for 24 hours, 30 μM of different derivatives and corresponding solvents were added for culture, with 3 parallel replicates for each group. After drug administration, the 96-well plate was placed in an incubator and cultured for another 72 hours.

[0138] (3) MTT assay: After culturing cells with the appropriate drug for 72 hours, add 30 μL of 5 mg / mL MTT solution and continue culturing at 37℃ for 2–4 hours. Discard the supernatant, taking care not to disrupt the crystals formed at the bottom of the wells. Add 150 μL of DMSO to each well, place on a shaker in the dark, and shake for about 10 minutes to fully dissolve the formazan crystals. Finally, use an ELISA reader to detect the absorbance at a wavelength of 570 nm. The tumor cell group treated with DMSO was used as the control group, and verapamil was used as a positive control. The inhibition rate of the derivative was calculated. Inhibition rate (%) = (mean OD value of the control group – mean OD value of the drug group) / mean value of the control group × 100%

[0139] Experimental results: At a drug concentration of 30 μM, the survival rate of drug-resistant tumor cells KBV treated with Vrp was approximately 40%, while the survival rate of drug-resistant tumor cells KBV treated with compounds 11a-11g, 12a-12b, 13a-13d, and 14a-14e was all above 80%, indicating that the cytotoxicity of these compounds was significantly lower than that of Vrp.

[0140] Table 1. Cytotoxicity evaluation results of PPD derivatives in KBV cells

[0141]

[0142]

[0143] Example 20: Evaluation of the antitumor MDR activity of PPD derivatives

[0144] Experimental methods:

[0145] (1) Cell plating: KBV cells in logarithmic growth phase and in good condition were digested and counted, according to a 2.5×10⁻⁶ m² / h²· ... 3 / wells were seeded into 96-well plates and cultured in a 37°C, 5% CO2 cell incubator;

[0146] (2) Cell drug administration: After cells adhered to the plate for 24 hours, 10 μM of different derivatives, 100 nM of paclitaxel, and DMSO were added as controls, with 3 replicates for each group. After drug administration, the 96-well plate was placed in an incubator and cultured for another 72 hours.

[0147] (3) MTT assay: After culturing cells with the appropriate drug for 72 hours, add 30 μL of 5 mg / mL MTT solution and continue culturing at 37℃ for 2–4 hours. Discard the supernatant, taking care not to disrupt the crystals formed at the bottom of the wells. Add 150 μL of DMSO to each well, place on a shaker in the dark, and shake for about 10 minutes to fully dissolve the formazan crystals. Finally, use an ELISA reader to detect the absorbance at a wavelength of 570 nm. The tumor cell group treated with DMSO was used as the control group, and verapamil was used as a positive control. The inhibition rate of the derivative was calculated. Inhibition rate (%) = (mean OD value of the control group – mean OD value of the drug group) / mean value of the control group × 100%

[0148] Experimental Results: Paclitaxel showed no cytotoxicity to the paclitaxel-resistant tumor cell line KBV at 100 nM. Even with the combined addition of 10 μM of saponin PPD and its parent compound 7-10, no cytotoxicity was observed, indicating that at this concentration, these compounds failed to increase the sensitivity of paclitaxel-resistant tumor cells KBV to paclitaxel. However, when PPD derivatives 11a-11g, 12a-12b, 13a-13d, and 14a-14e were added, the survival rate of KBV cells significantly decreased, indicating that they significantly increased the sensitivity of paclitaxel-resistant tumor cells KBV to paclitaxel, demonstrating a tumor resistance reversal effect. Among these, the preferred compounds 11a, 11b, 11c, 11d, 11f, 11g, 12a, 12b, 13a, 13b, 13c, 14a, and 14d exhibited significantly better tumor resistance reversal activity than the positive control drug verapamil (Vrp).

[0149] Table 2 Evaluation results of the antitumor MDR activity of PPD derivatives against KBV cells

[0150]

[0151]

[0152] The above description is only a partial embodiment of this application and an explanation of the technical principles used.

[0153] Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the combination of the above-described technical features, but should also cover other technical solutions formed by any combination of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with, but not limited to, technical features with similar functions disclosed in this application.

Claims

1. A PPD ring-opening derivative having the structural formula shown in Formula 11, 12, 13 or 14, or a pharmaceutically acceptable salt of a compound shown in Formula 11, 12, 13 or 14. in, R1, R2, R3, and R4 are each independently R x -KY-, where Y represents NH or O, K represents methylene or is absent, and R... x The following groups are either unsubstituted or substituted with one or more substituents: pyrazine, pyridine, azacyclobutane, thiophene, piperidine, furan, tetrahydrofuran, or thiazole; the substituents are C1 to C10 alkyl or tert-butoxycarbonyl groups.

2. The PPD ring-opening derivative as described in claim 1, characterized in that... R1 represents 2-pyrazinylmethylamine-1-yl, 4-pyridinylmethanol-1-yl, 3-N-Boc-azacyclobutanol-1-yl, 3-azacyclobutanol-1-yl, 2-thiophenemethylamine-1-yl, 3-N-Boc-azacyclobutanol-1-yl, or 4-N-Boc-piperidinol-1-yl; R2 represents 4-pyridinylmethanol-1-yl or 3-tetrahydrofuranol-1-yl; R3 represents 2-thiazolylethanol-1-yl, 2-pyridinylmethanol-1-yl, 4-pyridinylmethanol-1-yl, or 2-pyrazinylmethanol-1-yl; R4 represents furfurylol-1-yl, 2-thiazolylethanol-1-yl, 2-pyridinylmethanol-1-yl, 4-pyridinylmethanol-1-yl, or 2-pyrazinylmethanol-1-yl.

3. The PPD ring-opening derivative as described in claim 1, characterized in that... The PPD ring-opening derivative is one of the following compounds:

4. The method for preparing the PPD ring-opening derivative as described in claim 1, characterized in that, The method is shown in the following reaction formula:

5. The use of the PPD ring-opening derivatives and pharmaceutically acceptable salts thereof as described in any one of claims 1 to 3 in the preparation of tumor resistance reversal agents / tumor drug sensitizers, or in the preparation of tumor resistance reversal agents / tumor drug sensitizers comprising a pharmaceutically acceptable carrier.

6. The application as described in claim 5, characterized in that... The use of the aforementioned PPD ring-opening derivatives and their pharmaceutically acceptable salts in the preparation of tumor resistance reversal agents / tumor drug sensitizers that overcome P-glycoprotein-mediated tumor resistance or in the preparation of tumor resistance reversal agents / tumor drug sensitizers containing pharmaceutically acceptable carriers.

7. The use of the PPD ring-opening derivative and its pharmaceutically acceptable salt as described in any one of claims 1 to 3 in the preparation of an antitumor drug, wherein the method of application comprises a clinical antitumor drug and a tumor resistance reversal agent / tumor drug sensitizer, and the tumor resistance reversal agent / tumor drug sensitizer is the PPD ring-opening derivative and its pharmaceutically acceptable salt as shown in formula 11, 12, 13 or 14.

8. The application as described in claim 7, characterized in that... The tumors mentioned are breast cancer, colon cancer, cervical cancer, liver cancer, stomach cancer, or lung cancer; The clinical antitumor drug mentioned is paclitaxel.

9. A pharmaceutical composition for combating multidrug resistance, said pharmaceutical composition comprising the PPD ring-opening derivative as described in any one of claims 1 to 3 and a pharmaceutically acceptable salt thereof.

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