A biphenyloxadiazole ether derivative as a PD-1 / PD-L1 small molecule inhibitor and its synthesis method and use

Abstract

The present invention discloses biphenyloxadiazole ether derivatives as immune checkpoint inhibitors capable of blocking the PD-1 / PD-L1 signaling pathway, as well as their preparation methods and uses. These compounds, as shown in Formula I below, can modulate the PD-1 / PD-L1 signaling pathway to treat a variety of related tumor diseases through tumor immunotherapy, demonstrating potential drug development. The biphenyloxadiazole ether derivatives of the present invention, or their pharmaceutically acceptable salts, racemates, optical isomers, or solvates, are also disclosed. #imgabs0#

Description

Technical Field

[0001] The present invention relates to a compound of general formula I or its stereoisomers, solvates, prodrugs, metabolites, pharmaceutically acceptable salts or cocrystals, as well as a preparation method thereof, and its effects on inhibiting the PD-1 / PD-L1 pathway and anti-tumor effects. Background Art

[0002] Cancer, a challenge that remains unsolved by the global medical community, has become the second leading cause of death globally, second only to cardiovascular disease. China, the world's most populous country, saw 4.57 million new cancer cases in 2020, accounting for 23.7% of the global total. China also saw 3 million cancer deaths, representing 30% of all cancer deaths. This is primarily due to the high number of cancer patients in China, which ranks first in the world in cancer deaths. This has placed enormous social pressure and economic burden on China, posing unprecedented challenges to public health.

[0003] Immunotherapy has revolutionized cancer treatment and led to a paradigm shift in the fight against cancer. Key therapeutic strategies in cancer immunotherapy include cytokines (such as IL-2 and TNF-α), checkpoint inhibitors, chimeric antigen receptor (CAR) T cell therapy, adoptive cell transfer, cancer vaccines, oncolytic virotherapy, immune receptor agonist antibodies, and bispecific T cell engagers (BiTEs). Cancer immunotherapy was named Breakthrough of the Year by Science magazine in 2013. Immune checkpoint inhibitors, in particular, have shown considerable promise, with six approved by the US Food and Drug Administration (FDA) since 2011. Currently, these products are indicated for patients with specific types of skin cancer, head and neck cancer, lung cancer, bladder cancer, lymphoma, and kidney cancer. Immunotherapy based on immune checkpoint inhibition is now clinically considered the fifth anticancer therapy, following surgery, chemotherapy, radiotherapy, and targeted therapy. The immune checkpoint proteins PD-1 / PD-L1 and CTLA-4 are currently the most studied in clinical practice, with the former being particularly prominent. Their successful clinical application has significantly advanced the progress of cancer immunotherapy.

[0004] Currently, all PD-1 / PD-L1 drugs available for clinical use are monoclonal antibodies. However, as biologics, monoclonal antibodies suffer from some of the inherent drawbacks of biologics, such as poor oral bioavailability and difficulties in drug production. Furthermore, due to their long half-life and difficult-to-control immune responses, PD-1 / PD-L1 monoclonal antibodies have been associated with a variety of immune-related adverse reactions during clinical use, causing damage to normal organs and tissues, most commonly the skin, gastrointestinal tract, liver, lungs, and endocrine system. These shortcomings have prompted pharmaceutical researchers to explore small-molecule PD-1 / PD-L1 inhibitors as alternatives to antibody drugs. To date, there are no non-antibody small-molecule inhibitors of the PD-1 / PD-L1 signaling pathway on the market. Therefore, the development of novel small-molecule PD-1 / PD-L1 inhibitors with robust anti-tumor activity is of great significance. Summary of the Invention

[0005] The present invention provides a series of bifenthiophene oxadiazole ether derivatives that can be used to treat various related tumor diseases through tumor immunotherapy by regulating the PD-1 / PD-L1 signaling pathway, and a preparation method thereof.

[0006] Some embodiments of the present invention relate to a compound of formula I, wherein:

[0007]

[0008] R can be selected from

[0009]

[0010] Furthermore, the compound includes any one of the following compounds:

[0011]

[0012]

[0013] The synthetic route of the compound is as follows:

[0014]

[0015] The specific synthesis steps are as follows:

[0016] (1) Compound L1 undergoes diazotization and hydrolysis to generate compound L2;

[0017] (2) Compound L2 reacts with phenylboronic acid under Suzuki coupling conditions to produce L3;

[0018] (3) Compound L3 is replaced by ethyl bromoacetate to obtain compound L4;

[0019] (4) Compound L4 reacts with hydrazine hydrate to produce compound L5;

[0020] (5) Compound L5 reacts with carbon disulfide to cyclize to compound L6;

[0021] (6) Compound L6 reacts with appropriate benzyl bromide benzaldehyde to produce compounds L7a and L7b;

[0022] (7) Compounds L7a,b were subjected to sodium cyanoborohydride-mediated reductive amination to give compound PL1-27.

[0023] The solvents used in the diazotization and hydrolysis reactions in step (1) include but are not limited to concentrated sulfuric acid, water, cyclopentyl methyl ether, ethyl acetate, or a mixed solvent optionally composed of these solvents; the base used includes but is not limited to sodium nitrite; and the reaction temperature is 0°C to 100°C.

[0024] The solvent used in the coupling reaction in step (2) includes but is not limited to toluene, water, ethyl acetate or a mixed solvent optionally composed of these solvents; the catalyst used is bistriphenylphosphine palladium dichloride; the reagents used include but are not limited to sodium carbonate and phenylboric acid; and the reaction temperature is 85° C. to 95° C.

[0025] The solvent used in step (3) includes but is not limited to acetone, water, ethyl acetate or a mixed solvent optionally composed of these solvents; the reagent used is ethyl bromoacetate; the base used is anhydrous potassium carbonate; the reaction temperature is 55°C to 65°C

[0026] The solvent used for the hydrazine hydrate reaction in step (4) includes but is not limited to ethanol and water; the reaction temperature is 75°C to 85°C.

[0027] The solvent used in the cyclization reaction in step (5) includes but is not limited to ethanol, water, dilute hydrochloric acid solution or a mixed solvent optionally composed of these solvents; the reagent used is carbon disulfide; the base used is potassium hydroxide; and the reaction temperature is 75°C to 85°C.

[0028] The solvent used in step (6) includes but is not limited to acetone, water, ethyl acetate or a mixed solvent optionally composed of these solvents; the base used is potassium carbonate; the reagent used is 3-(bromomethyl)benzaldehyde or 4-(bromomethyl)benzaldehyde; and the reaction temperature is 55°C to 65°C.

[0029] The solvent used in the sodium cyanoborohydride-mediated reductive amination reaction in step (7) is dichloromethane, methanol, or a mixed solvent optionally composed of these solvents; the acid used is glacial acetic acid, and the reagent used is the corresponding amine; the reaction temperature is 20° C. to 30° C.

[0030] The present application also discloses the use of the biphenyloxadiazole ether derivative, or a pharmaceutically acceptable salt, racemate, optical isomer or solvent compound thereof in the preparation of an inhibitor having PD-1 / PD-L1 inhibitory activity.

[0031] The present application also discloses the use of the biphenyloxadiazole ether derivative, or its pharmaceutically acceptable salt, racemate, optical isomer or solvent compound in the preparation of anti-tumor drugs.

[0032] The present application also discloses a pharmaceutical composition, which contains the biphenyloxadiazole ether derivative or its pharmaceutically acceptable salt, racemate, optical isomer or solvent compound as an active ingredient, and a pharmaceutically acceptable carrier.

[0033] The pharmaceutical composition described in the present application is a capsule, powder, tablet, granule, pill, injection, syrup, oral solution, inhalant, ointment, suppository or patch.

[0034] Beneficial effects: This application provides a class of PD-1 / PD-L1 small molecule immune checkpoint inhibitors with novel structure, simple preparation as small molecule inhibitors, and convenient industrial production; they can treat various related tumor diseases with tumor immunotherapy by regulating the PD1 / PD-L1 signaling pathway, and have potential drug development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the PL17 H NMR spectrum.

[0036] Figure 2 This is the PL17 carbon nuclear magnetic resonance spectrum.

[0037] Figure 3 It is a PL17 high-resolution mass spectrometer.

[0038] Figure 4 This is the PL17 high performance liquid chromatography.

[0039] Figure 5 It is a PL17 / h / mPD-L1 binding assay.

[0040] Figure 6 It is a PL17 / HepG2 / Jukart cell co-culture model.

[0041] Figure 7 This is an in vivo tumor inhibition experiment of PL17. DETAILED DESCRIPTION

[0042] The present application is further described below with reference to the following embodiments.

[0043] Example 1: Synthesis of PL1

[0044]

[0045] Synthesis route:

[0046]

[0047] Synthesis of compound L2

[0048] To a solution of L1 (10.0 g, 53.76 mmol) in concentrated sulfuric acid (100 mL) was slowly added sodium nitrite (4.2 g, 59.14 mmol) under ice-bath conditions. The thick suspension was warmed to room temperature and stirred for more than 1 hour until no lumps were visible. The mixture was then slowly poured into a solution of cyclopentyl methyl ether / water (300 mL:300 mL) and stirred at 100°C for another 2 hours. After the reaction was complete, the mixture was extracted with ethyl acetate (3 × 300 mL). The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and concentrated. The crude product was purified by silica gel chromatography (petroleum ether:ethyl acetate = 10:1) to afford L2 as a yellow solid (7.3 g, 73%).

[0049] Synthesis of compound L3

[0050] L2 (4.8 g, 25.6 mmol), phenylboronic acid (3.7 g, 30.7 mmol), and bis(triphenylphosphine)palladium dichloride (1.8 g, 2.56 mmol) were suspended in toluene (80 mL) and aqueous sodium carbonate solution (8.2 g, 16 mL). After replacing the air with nitrogen three times, the reaction mixture was heated at 90°C for 10 hours. The residue was removed from the reaction mixture by vacuum filtration through celite, and then extracted with ethyl acetate (3 × 80 mL). The organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated. The crude product was purified by silica gel chromatography (oil ether:ethyl acetate = 60:1 to 20:1) to afford L3 as a colorless liquid (3.6 g, 75%).

[0051] Synthesis of compound L4

[0052] L3 (2.2 g, 11.8 mmol) was dissolved in acetone (20 mL) and anhydrous potassium carbonate (3.3 g, 23.6 mmol) and ethyl bromoacetate (2.4 g, 14.2 mmol) were added in sequence. The suspension was heated to 60° C. overnight under reflux and nitrogen protection. The yellow suspension was cooled to room temperature and the solvent was removed in vacuo. The solid was dissolved in water and ethyl acetate and the layers were separated. The aqueous layer was extracted with additional ethyl acetate (3×20 mL), and the combined organic layers were washed with brine (2×20 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give L4 (2.8 g, 88%) as a light yellow solid.

[0053] Synthesis of compound L5

[0054] A solution of L4 (2.0 g, 7.8 mmol) and hydrazine hydrate (0.78 g, 15.6 mmol) in ethanol (20 mL) was refluxed for 5 h. The solvent was evaporated under reduced pressure, and the residue was poured into crushed ice to give PL5 (1.6 g, 84%).

[0055] Synthesis of compound L6

[0056] To an ethanol (200 mL) solvent was added L5 (2.2 g, 8.6 mmol), potassium hydroxide (0.53 g, 9.4 mmol), and carbon disulfide (2.0 g, 15.7 mmol) with stirring. The reaction was degassed with nitrogen and heated under reflux overnight, monitored by TLC. After completion of the reaction, the solvent was evaporated under reduced pressure, and water (200 mL) was added. The aqueous phase was acidified to pH 2-3 with 1N dilute hydrochloric acid solution, filtered, and dried to obtain L6 (1.7 g, 68%) as a white solid.

[0057] Synthesis of compound L7a

[0058] L6 (2.0 g, 6.70 mmol) was dissolved in acetone (20 mL), and anhydrous potassium carbonate (3.24 g, 23.45 mmol) and 4-bromomethylbenzaldehyde (1.6 g, 8.04 mmol) were added sequentially. The reaction was allowed to reflux under nitrogen overnight. After the reaction was complete, the solvent was evaporated and the solid was dissolved in water and ethyl acetate and the layers were separated. The aqueous layer was extracted with additional ethyl acetate (3 × 20 mL), and the combined organic layers were washed with brine (2 × 20 mL), dried over anhydrous sodium sulfate, filtered, and concentrated to afford L7a (2.06 g, 73.8%) as a light yellow solid.

[0059] Synthesis of compound PL1

[0060] Intermediate L7a (0.24 g, 0.6 mmol) was dissolved in a mixture of dichloromethane (5 mL) and methanol (5 mL). Morpholine (78.4 mg, 0.9 mmol), glacial acetic acid (2 drops), and sodium cyanoborohydride (0.19 g, 3 mmol) were added. The reaction was stirred at room temperature overnight and monitored by TLC. The solvent was evaporated under reduced pressure, and the crude product was purified on a silica gel column (DCM:MeOH = 100:1 to 5:1) to obtain PL1 as a light yellow oil. 1H NMR (400MHz, CDCl3-d) δ7.43(s,1H),7.41(s,1H),7.40(s,1H),7.37(d,J=7.2Hz,1H),7.35(s,1H),7.32(s,2H),7.30(s,1H),7.2 8(s,1H),7.22(d,J=7.9Hz,1H),7.02–6.95(m,2H),5.29(s,2H),4.50(s,2H),3.76(s,4H),3.56(s,2H),2.52(s,4H),2.16(s,3H).

[0061] Example 2

[0062]

[0063] Referring to the method of Example 1, replacing morpholine with N-(2-aminoethyl)acetamide, compound PL2 can be prepared. 1 HNMR (400MHz, CDCl3-d) δ7.43(t,J=7.6Hz,4H),7.37(t,J=6.8Hz,3H),7.32(s,1H),7.29(d,J=5.0Hz,1H),7.22(d,J=8.0Hz,1H),7.02 –6.95(m,2H),5.29(s,2H),4.48(s,2H),3.91(s,2H),3.44(d,J=5.1Hz,2H),2.94–2.84(m,2H),2.16(s,3H),2.02(s,2H),1.98(s,3H).

[0064] Example 3

[0065]

[0066] Referring to the method of Example 1, replacing morpholine with (R)-pyrrolidin-3-ol, compound PL3 can be prepared. 1H NMR(400MHz, CDCl3-d)δ7.44(t,J=5.5Hz,3H),7.40(s,2H),7.38(s,1H),7.33–7.27(m,3H ),7.22(d,J=7.9Hz,1H),7.02–6.94(m,2H),5.29(s,2H),4.49(s,2H),4.44(s,1H),3.79(s ,3H),3.24(dd,J=16.2,8.0Hz,1H),3.04(d,J=11.2Hz,1H),2.80(dd,J=11.0,5.1Hz,1H),2 .66(dd,J=16.4,9.1Hz,1H),2.32–2.23(m,1H),2.16(s,3H),1.97(dd,J=14.1,6.9Hz,1H).

[0067] Example 4

[0068]

[0069] Referring to the method of Example 1, replacing morpholine with D-serine, compound PL4 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.44(s,2H),7.42(s,1H),7.39(s,2H),7.36(s,2H),7.30(d,J=7.2Hz,2H),7.28–7.21(m,1H),7.13(d,J=8.1Hz,1H),6. 89(d,J=7.2Hz,1H),5.44(s,2H),4.52(s,2H),3.94(d,J=13.3Hz,1H),3 .85(d,J=13.6Hz,1H),3.62(d,J=6.5Hz,3H),3.10(s,1H),2.06(s,3H).

[0070] Example 5

[0071]

[0072] Referring to the method of Example 1, replacing morpholine with glycine, compound PL5 can be prepared. 1H NMR (400MHz, CDCl3-d) δ7.42–7.36(m,4H),7.33(d,J=7.2Hz,1H),7.28(d,J=7.4Hz,4H),7.19(t,J=7.9Hz,1H) ,6.98–6.91(m,2H),5.25(s,2H),4.45(s,2H),3.78(s,2H),3.28(s,1H),2.12(s,3H),1.27(d,J=11.6Hz,2H).

[0073] Example 6

[0074]

[0075] Referring to the method of Example 1, replacing morpholine with 2-aminoethane-1-ol, compound PL6 can be prepared. 1 H NMR (400MHz, CDCl3-d) δ7.47–7.42(m,3H),7.41(s,2H),7.40–7.34(m,2H),7.32(s,1H),7.30(d,J=5.0Hz,1H),7.22(d,J=7. 9Hz,1H),6.98(t,J=8.7Hz,2H),5.28(s,2H),4.48(s,2H),3.99(s,2H),3.76(s,2H),2.92(s,2H),2.16(s,3H),1.98(s,2H).

[0076] Example 7

[0077]

[0078] Referring to the method of Example 1, replacing morpholine with 2-amino-2-methylpropionic acid, compound PL7 can be prepared. 1 HNMR(400MHz,DMSO-d6)δ7.39(m,7H),7.30(s,2H),7.25(s,1H),7.14(s,1H), 6.90(s,1H),5.44(s,2H),4.52(s,2H),3.82(s,2H),2.06(s,3H),1.29(s,6H).

[0079] Example 8

[0080]

[0081] Referring to the method of Example 1, replacing morpholine with azetidine-3-carboxylic acid, compound PL8 can be prepared. 1HNMR (400MHz, DMSO-d6) δ7.44(t,J=7.1Hz,2H),7.37(d,J=7.0Hz,1H),7.31(dd,J=12.1,7.8Hz,4H),7.24(t,J=7.9Hz,1H),7.17(d,J=7 .5Hz,2H),7.12(d,J=8.1Hz,1H),6.89(d,J=7.4Hz,1H),5.44(s,2H),4.48(s,2H),3.48(s,2H),3.34(s,2H),3.15(s,3H),2.05(s,3H).

[0082] Example 9

[0083]

[0084] Referring to the method of Example 1, replacing morpholine with 3-(methylamino)propanol, compound PL9 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.43(d,J=6.6Hz,2H),7.36(d,J=6.8Hz,3H),7.29(d,J=6.4Hz,2H),7.23(s,3H),7.12(d,J=7.6Hz,1H), 6.89(d,J=6.7Hz,1H),5.44(s,2H),4.50(s,2H),3.47(s,2H),3.42(s,3H),2.42(s,2H),2.10(s,3H),2.05(s,3H),1.60(s,2H).

[0085] Example 10

[0086]

[0087] Referring to the method of Example 1, replacing morpholine with piperidine-2-carboxylic acid, compound PL10 can be prepared. 1H NMR (400MHz, DMSO-d6) δ7.44(t,J=7.1Hz,2H),7.36(d,J=6.8Hz,3H),7.31(s,1H),7.2 5(dd,J=15.0,8.2Hz,4H),7.13(d,J=8.1Hz,1H),6.89(d,J=7.4Hz,1H),5.44(s,2H),4. 50(s,2H),3.84(d,J=13.5Hz,1H),3.46(d,J=13.4Hz,1H),3.04(s,1H),2.81(s,1H),2. 17(s,1H),2.05(s,3H),1.91(s,1H),1.79(d,J=19.6Hz,1H),1.70(s,1H),1.44(s,3H).

[0088] Example 11

[0089]

[0090] Referring to the method of Example 1, replacing morpholine with 3-aminopropane-1-ol, compound PL11 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.44(t,J=7.3Hz,2H),7.39–7.33(m,3H),7.32–7.25(m,4H),7.23(d,J=7.9Hz,1H),7.12(d,J=8.2Hz,1H),6.89(d,J= 7.5Hz,1H),5.44(s,2H),4.50(s,2H),3.70(s,2H),3.44(t,J=6.1Hz,2 H),3.17(s,1H),2.58(t,J=6.9Hz,2H),2.05(s,3H),1.62–1.54(m,2H).

[0091] Example 12

[0092]

[0093] Referring to the method of Example 1, replacing morpholine with 2-(methylamino)ethane-1-ol, compound PL12 can be prepared. 1HNMR(400MHz, DMSO-d6)δ9.43(s,1H),7.51(d,J=8.0Hz,2H),7.47–7.41(m,4H),7.37(d,J=7.2Hz,1H),7.29(d,J=7.1Hz,2H),7.25(t,J=7.9Hz ,1H),7.13(d,J=8.2Hz,1H),6.89(d,J=7.5Hz,1H),5.44(s,2H),4.55(s ,2H),4.18(s,2H),3.69(s,2H),3.00(s,2H),2.64(s,3H),2.05(s,3H).

[0094] Example 13

[0095]

[0096] Referring to the method of Example 1, replacing morpholine with 3-aminopropionic acid, compound PL13 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.44(t,J=7.3Hz,2H),7.38(d,J=7.7Hz,3H),7.29(t,J=8.0Hz,4H),7.23(d,J=7.9Hz,1H),7.12(d,J=8.2Hz,1H ),6.89(d,J=7.5Hz,1H),5.44(s,2H),4.51(s,2H),3.74(s,2H),2.73(t,J=6.5Hz,2H),2.29(t,J=6.5Hz,2H),2.05(s,3H),1.90(s,1H).

[0097] Example 14

[0098]

[0099] Referring to the method of Example 1, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL14 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.43(d,J=7.3Hz,2H),7.36(t,J=7.2Hz,2H),7.29(d,J=7.8Hz,3H),7.25–7.18(m,3H),7.12( d,J=8.2Hz,1H),6.88(d,J=7.6Hz,1H),5.42(s,2H),4.51(s,2H),3.54(s,4H),3.41(s,2H),2.30(s,4H),1.91(s,3H).

[0100] Example 15

[0101]

[0102] Referring to the method of Example 2, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL15 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.83(s,1H),7.47–7.41(m,3H),7.38(d,J=7.3Hz,1H),7.32–7.26(m,5H),7.23(d,J=7.7Hz,1H),7.13(d,J=8.2Hz,1H),6.89 (d,J=7.5Hz,1H),5.44(s,2H),4.52(s,2H),3.73(s,2H),3.16(dd,J=12.0 ,6.0Hz,2H),2.59(t,J=6.3Hz,2H),2.05(s,3H),1.91(s,1H),1.79(s,3H).

[0103] Example 16

[0104]

[0105] Referring to the method of Example 3, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL16 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.43(d,J=5.4Hz,2H),7.38(s,2H),7.28(s,3H),7.23(d,J=6.9Hz,3H),7.13(d,J=6.6Hz,1H),6.89(d,J=6.0Hz,1H),5.4 3(s,2H),4.51(s,2H),4.19(s,1H),3.56(s,2H),2.63(d,J=48.9Hz,2H) ,2.46–2.29(m,2H),2.05(s,3H),1.98(s,1H),1.91(s,1H),1.54(s,1H).

[0106] Example 17

[0107]

[0108] Referring to the method of Example 4, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL17 can be prepared. 1H NMR (400MHz, DMSO-d6) δ12.43(s,1H),7.47–7.40(m,3H),7.37(d,J=6.9Hz,1H),7.28(d,J=7.2Hz,3H),7.25–7.20(m,3H),7.10(d,J=8.2Hz ,1H),6.87(d,J=7.4Hz,1H),5.40(s,2H),4.51(s,2H),3.77(d,J=14.2Hz,2H),3.60(d,J=14.4Hz,2H),3.23(t,J=5.9Hz,1H),2.03(s,3H).

[0109] Example 18

[0110]

[0111] Referring to the method of Example 5, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL18 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.42(s,5H),7.26(s,5H),7.10(s,1H),6.87(s,1H),5.40(s,2H),4.51(s,2H),3.68(s,2H),3.13(s,2H),2.02(s,3H).

[0112] Example 19

[0113]

[0114] Referring to the method of Example 6, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL19 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.45(s,2H),7.43(s,1H),7.40–7.35(m,1H),7.30(d,J=7.5Hz,4H),7.28–7.21(m,2H),7.13(d,J=8.2H z,1H),6.89(d,J=7.5Hz,1H),5.44(s,2H),4.53(s,2H),3.80(s,2H),3.51(t,J=5.5Hz,2H),2.66(t,J=5.5Hz,2H),2.05(s,3H).

[0115] Example 20

[0116]

[0117] Referring to the method of Example 1, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde and replacing morpholine with (2R,4R)-4-hydroxypyrrolidine-2-carboxylic acid, compound PL20 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.43 (dd, J=13.9, 6.6Hz, 3H), 7.37 (d, J=7.2Hz, 1H), 7.30 (s,2H),7.28(d,J=7.4Hz,3H),7.23(d,J=7.9Hz,1H),7.13(d,J=8.3Hz,1H),6.89 (d,J=7.5Hz,1H),5.44(s,2H),4.52(s,2H),4.16(s,2H),3.25–3.19(m,1H),3.18 (s,3H),2.81(d,J=9.9Hz,1H),2.30(s,1H),2.05(s,2H),1.76(d,J=11.1Hz,1H).

[0118] Example 21

[0119]

[0120] Referring to the method of Example 7, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL21 can be prepared. 1 H NMR(400MHz,DMSO-d6)δ7.53(s,1H),7.43(s,2H),7.36(s,3H),7.30(s,3H),

[0121] 7.24(s,1H),7.14(s,1H),6.89(s,1H),5.44(s,2H),4.53(s,2H),3.84(s,2H),2.04(s,3H),

[0122] 1.89(s,1H),1.31(s,6H).

[0123] Example 22

[0124]

[0125] Referring to the method of Example 8, 4-bromomethylbenzaldehyde was replaced with 3-bromomethylbenzaldehyde to obtain the compound

[0126] PL22. 1 H NMR(400MHz, DMSO-d6)δ7.43(d,J=7.0Hz,2H),7.37(d,J=6.9Hz,1H),

[0127] 7.35–7.20(m,6H),7.19–7.09(m,2H),6.89(d,J=7.2Hz,1H),5.43(s,2H),4.50(s,2H),

[0128] 3.49(s,2H),3.34(s,2H),3.15(s,2H),2.04(s,3H),1.90(s,1H).

[0129] Example 23

[0130]

[0131] Referring to the method of Example 9, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL23 can be prepared. 1 H NMR(400MHz, CDCl3-d)δ7.46(s,1H),7.43(s,1H),7.41(s,1H),7.39–7.35

[0132] (m,2H),7.33(d,J=5.3Hz,2H),7.30(d,J=6.0Hz,2H),7.22(d,J=7.9Hz,1H),6.98(t,J

[0133] =8.5Hz,2H),5.29(s,2H),4.50(s,2H),3.80(t,J=5.2Hz,2H),3.77(s,2H),2.83(t,J=

[0134] 6.1Hz,2H),2.40(s,3H),2.16(s,3H),1.91–1.82(m,2H).

[0135] Example 24

[0136]

[0137] Referring to the method of Example 10, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL24 can be prepared. 1H NMR(400MHz, DMSO-d6)δ7.43(t,J=7.3Hz,2H),7.40–7.34(m,2H),7.29(d,J=6.9Hz,3H),7. 24(t,J=8.0Hz,3H),7.12(d,J=8.1Hz,1H),6.88(d,J=7.5Hz,1H),5.43(s,2H),4.51(s,2H), 3.83(d,J=13.4Hz,1H),3.44(d,J=13.4Hz,1H),3.05(d,J=3.8Hz,1H),2.85–2.76(m,1H),2. 20–2.09(m,1H),2.04(s,3H),1.77(s,1H),1.69(d,J=9.1Hz,1H),1.44(s,3H),1.33(s,1H).

[0138] Example 25

[0139]

[0140] Referring to the method of Example 11, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL25 can be prepared. 1 H NMR (400MHz, CDCl3-d) δ7.41(d,J=7.3Hz,3H),7.36(d,J=7.2Hz,1H),7.31(d,J=5.6Hz,3H),7.28(d,J=5.0Hz,2H),7.21(t,J=7.9Hz,1H),6. 96(t,J=7.9Hz,2H),5.25(s,2H),4.50(s,2H),3.64(t,J=5.1Hz,1H),3 .59(s,2H),2.64(s,1H),2.14(s,3H),1.84–1.71(m,2H),1.65(s,2H).

[0141] Example 26

[0142]

[0143] Referring to the method of Example 12, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL26 can be prepared. 1H NMR (400MHz, CDCl3-d) δ7.48(s,1H),7.45–7.40(m,3H),7.36–7.33(m,2H),7.33–7.27(m,3H),7.22(t,J=7.9Hz,1H),6.98(t,J=8. 3Hz,2H),5.28(s,2H),4.49(s,2H),3.84(s,2H),3.80–3.76(m,2H),3.50(s,1H),2.79(t,J=5.0Hz,2H),2.45(s,3H),2.15(s,3H).

[0144] Example 27

[0145]

[0146] Referring to the method of Example 13, replacing 4-bromomethylbenzaldehyde with 3-bromomethylbenzaldehyde, compound PL27 can be prepared. 1 H NMR (400MHz, DMSO-d6) δ7.46–7.40(m,3H),7.37(d,J=7.2Hz,1H),7.30(s,2H),7.29–7.25(m,3H),7.23(d,J=7.9Hz,1H),7.12(d,J= 8.1Hz,1H),6.88(d,J=7.5Hz,1H),5.43(s,2H),4.51(s,2H),3.75(s,2H),2.73(t,J=6.4Hz,2H),2.29(t,J=6.4Hz,2H),2.04(s,3H).

[0147] In vitro and in vivo pharmacological experiments have demonstrated that the PD-1 / PD-L1 inhibitory activity of the present invention can be used to prepare anti-tumor drugs. The following are the pharmacological experimental results of the compounds of the present invention:

[0148] Experimental Example 1: HTRF (Homogeneous Time-Resolved Fluorescence) Experiment

[0149] (1) Reagents and instruments

[0150] PD-1 / PD-L1 kit 10,000 tests (64PD1PEH);

[0151] Multifunctional 96-well white plate (Unionway);

[0152] Multifunctional microplate reader (Tecan, Infinite M1000 Pro);

[0153] Precision pipette tips (Eppendorf, J90066J)

[0154] Manual pipette (Eppendorf, M39970J)

[0155] Biological grade dimethyl sulfoxide (DMSO) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0156] (2) Experimental steps

[0157]

[0158] (3) Data processing:

[0159] (a) Calculate the ratio of the acceptor and donor emission signals for each well: Ratio = OD 665 / OD 620 x10 4

[0160] (b) Calculation of CV%: CV(%) = standard deviation / average ratio x 100

[0161] (c) Draw an S-shaped graph based on the average inhibition rate of each compound from high to low concentrations, and calculate the half-maximal inhibition concentration (IC) of each test sample. 50 ).

[0162] (4) Experimental results

[0163] The following table shows the activity range or IC of the compounds against PD-1 / PD-L1 interaction inhibition 50 The scope is as follows:

[0164]

[0165]

[0166] The above results indicate that most of the compounds in the examples of this application exhibited good PD1 / PD-L1 inhibitory activity, with Example 17 showing the best activity, reaching 16.7 nM, significantly superior to the positive reference BMS202. This demonstrates that the bifenthiodiazole ether derivatives of the present invention can be used as immune checkpoint PD-1 / PD-L1 inhibitors.

[0167] Experimental Example 2: Surface Plasmon Resonance (SPR) Experiment

[0168] To further verify whether PL17 can cross-react with h / m PD-L1, we used surface plasmon resonance (SPR) experiments to determine the binding affinity of PL17 to h / m PD-L1. Figure 5 As shown, PL17 binds to h / mPD-L1 and mPD-L1 with similar affinity, K DThe values were 11.4 nM and 73.1 nM, respectively, indicating that PL17 could cross-react with h / mPD-L1 with strong affinity.

[0169] Experimental Example 3: HepG2 / Jurkat T cell co-culture experiment

[0170] To evaluate the efficacy of the preferred compound PL17 in inducing anti-tumor immunity, we monitored the effect of compound PL17 on the killing of HepG2 cells by Jurkat T cells using a cell co-culture assay. Figure 6 As shown in A / B, compound PL17 showed no toxicity to Jurkat T cells or HepG2 cells within the corresponding concentration range. Meanwhile, Jurkat T cells alone failed to show anti-tumor activity against HepG2 cells. When HepG2, PL17, and Jurkat T cells were co-cultured, the number of dead tumor cells increased in a concentration-dependent manner, with an IC 50 The value was 4.32μM ( Figure 6 C / D). These results indicate that PL17 can effectively enhance the cytotoxicity of Jurkat T cells against HepG2 cells in a cell co-culture model.

[0171] Experimental Example 4: In vivo pharmacodynamic study of compound PL17 on B16-F10 mouse tumor model

[0172] To evaluate the in vivo efficacy of PL17, we selected a B16-F10 mouse tumor model for study. C57 male mice (18-20 g) were randomly divided into four groups: control group, low dose (8 mg / kg), medium dose (15 mg / kg), and high dose (30 mg / kg). Figure 7 As shown in Figures A and C, compound PL17 exhibited a highly effective tumor inhibitory effect. Compared to the solvent control group, different doses of PL17 reduced tumor mass by 53.2%, 75.9%, and 88.6%, respectively. Correspondingly, tumor volume decreased by 74.4%, 84.3%, and 95.4%, respectively. A summary analysis of the body weight of the mice also revealed that during the PL17 treatment period, the body weight of the mice remained relatively stable, with no signs of weight loss. This suggests that while PL17 exerted its anti-tumor efficacy, it did not affect the quality of life of the mice. Figure 7 D).

Claims

1. A biphenyl oxadiazole ether compound, characterized in that: The compound includes any of the following structures:

2. A method for preparing the biphenyloxadiazole ether compound according to claim 1, wherein the synthesis route of the compound is as follows: R is selected from or (1) Compound L1 undergoes diazotization and hydrolysis to generate compound L2; (2) Compound L2 reacts with phenylboronic acid under Suzuki coupling conditions to produce L3; (3) Compound L3 is replaced by ethyl bromoacetate to obtain compound L4; (4) Compound L4 reacts with hydrazine hydrate to produce compound L5; (5) Compound L5 reacts with carbon disulfide to cyclize to compound L6; (6) Compound L6 reacts with the corresponding benzyl bromide benzaldehyde to produce compounds L7a and L7b; (7) Compounds L7a and L7b were reacted via sodium cyanoborohydride-mediated reductive amination to afford compound PL; The compound PL is the biphenyloxadiazole ether compound.

3. The use of the biphenyloxadiazole ether compound according to claim 1, characterized in that: The application is the use of the biphenyloxadiazole ether compound in the preparation of an inhibitor with PD-1 / PD-L1 inhibitory activity.

4. The use of the biphenyloxadiazole ether compound according to claim 1, characterized in that: The application is the application of the biphenyloxadiazole ether compound in the preparation of anti-tumor drugs.

5. A pharmaceutical composition containing the bifenthiodiazole ether compound according to claim 1, characterized in that: The pharmaceutical composition comprises the bifenthiophene oxadiazole compound as an active ingredient and a pharmaceutically acceptable carrier.

6. The pharmaceutical composition of the bifenthiodiazole ether compound according to claim 5, characterized in that: The pharmaceutical composition is a capsule, powder, tablet, granule, pill, injection, syrup, oral solution, inhalant, ointment, suppository or patch.

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