3-site arylated derivative of indole as well as synthesis method and application of 3-site arylated derivative

Abstract

The invention discloses a 3-site arylated derivative of indole as well as a synthesis method and application of the 3-site arylated derivative. 2-methylindole is used as a raw material and reacts with arylboronic acid after iodination, and a target compound is obtained. The method disclosed by the invention is simple in synthesis step and mild in reaction condition, and the C3-site arylated derivative of indole has an obvious inhibition effect on Zika virus and is expected to be used in potential antiviral drugs.

Description

Technical Field

[0001] The invention belongs to the field of organic chemistry, and specifically relates to a 3-arylated indole derivative and a synthesis method and application thereof. Background Art

[0002] Indole is a basic heterocyclic compound that is present in many compounds and plays a vital role in biology, such as the essential amino acid tryptophan, its metabolite tryptamine, and the neurotransmitters serotonin and melatonin. This nitrogen-containing aromatic heterocycle is also part of many natural products. In the field of medicinal chemistry, indole is considered a special scaffold because it can bind many biological targets with high affinity. As a result, indole is a common component of many biologically active compounds. In fact, the number of such compounds reported in the literature is so large that Smythe wrote in a review published in 2003: "Indoles probably represent the most important of all structural classes in drug discovery."

[0003] In 2014, Njardarson performed an analysis of all drugs marketed in the United States as of 2012 and showed that 59% of the drugs contained at least one nitrogen heterocycle. Of all saturated and unsaturated nitrogen-containing heterocycles, indole ranked ninth with a frequency of 6.8%. Another analysis by Taylor, published that same year, showed that indole was the 13th most common ring system in all FDA-approved drugs as of 2012. Both Njardarson and Taylor found that indole was the fourth most common aromatic heterocycle in drugs, after pyridine, imidazole, and thiazole rings. Methods that allow for late-stage functionalization of indoles are important for medicinal chemistry use.

[0004] Prominently, among various functionalized indole groups, 3-arylindole skeletons are attractive heterocyclic frameworks that are ubiquitous in organic synthesis, material science, pharmaceuticals, and natural molecules. Undoubtedly, direct C-H bond functionalization of pre-existing indole rings is a more powerful and efficient tool for constructing these structurally diverse heterocyclic scaffolds. Accordingly, aryl halides, aryl hydrazines, diaryl azonium salts, benzoic acids, and diaryl azonium salts have been used as arylation reagents. Despite these reported achievements, direct C-3 arylation of indoles with readily available arylation reagents remains rare.

[0005] In view of the above-mentioned shortcomings of the prior art, it is necessary to develop economical and effective carbon 3-arylated derivative prodrugs of 3-aryl-substituted indoles. Summary of the invention

[0006] In order to overcome the above technical defects, the present invention provides a 3-arylated derivative of indole and its synthesis method and application, and studies its synthesis method and active application of the compound. Using 2-methylindole as a raw material, iodination followed by boric acid coupling, a two-step reaction is performed to obtain a carbon 3-arylated derivative compound containing biologically active indole. The indole derivative prodrug has a simple synthesis step and a high yield. It has been tested for its anti-Zika virus activity and has a significant inhibitory effect.

[0007] The present invention provides a 3-arylated derivative of indole, which is at least one of the following structures:

[0008]

[0009] The present invention also provides a method for synthesizing the 3-arylated derivative of the indole, comprising the following steps:

[0010] (1) Compound 1 and iodine are used as raw materials, alkalized with potassium hydroxide and then iodinated to obtain compound 2;

[0011] (2) Compound 2 reacts with arylboronic acid 3 or 4 in the presence of palladium acetate, S-PhOS ligand and anhydrous sodium carbonate to obtain the target compound.

[0012] The reaction equation is shown as follows:

[0013]

[0014] Furthermore, in step (1), the reaction solvent is DMF, the molar ratio of compound 1, elemental iodine and potassium hydroxide is 1:1:(2-3), the reaction temperature is room temperature, and after compound 1 reacts with potassium hydroxide for 10-30 minutes, the iodine solution in DMF is added.

[0015] Furthermore, in step (2), the reaction solvent is a mixed solvent of toluene: water: ethanol = (2-4): 1: 1, by volume ratio, the molar ratio of compound 2, aryl boronic acid 3 or 4, palladium acetate, S-PhOS and anhydrous sodium carbonate is 1: (1-1.5): (0.01-0.05): (0.1-0.2): (4-6), and the reaction temperature is 90-110°C.

[0016] The present invention also provides the use of the 3-arylated indole derivative in the preparation of antiviral drugs.

[0017] Furthermore, in the above technical solution, the virus shown is Zika virus.

[0018] The beneficial effects of the present invention are:

[0019] 1. The present invention uses 2-methylindole as a raw material and synthesizes the carbon 3 arylated derivative of indole through a two-step reaction, thereby avoiding the problems of a lengthy synthesis route, harsh reaction conditions, and low yield, and reducing potential safety hazards.

[0020] 2. The carbon 3-position arylated derivatives 5 and 6 of the indole of the present invention exhibited significant inhibitory effects on the ZIKV-NLuc recombinant virus. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Experimental steps for preliminary screening of compounds that inhibit ZIKV-NLuc luciferase activity;

[0022] Figure 2 is the luciferase expression level of 5 μM of the two compounds;

[0023] Figure 3 is the EC of compound 5 50 (Compound 5EC 50 =8.18 μM);

[0024] Figure 4 is the CC of compound 5 50 (Compound 5CC 50 =118.4 μM);

[0025] Figure 5 is the EC of compound 6 50 (Compound 6EC 50 =1.367 μM);

[0026] Figure 6 is the CC of compound 6 50 (Compound 6CC 50 =108.7 μM). Specific embodiments

[0027] The present invention will be further described below by specific examples. These embodiments should be understood to be only used to illustrate the present invention and not to limit the scope of protection of the present invention. After reading the content of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

[0028] Example 1

[0029] Synthesis of compound 5:

[0030]

[0031] At room temperature, compound 1 (1.00 mmol) and KOH (2.5 mmol, 2.5 eq) were added to a round-bottom flask, and DMF (10 mL) was added to fully dissolve compound 1. The mixture was stirred for 20 minutes, and then a DMF solution (6 mL) of iodine (1.00 mmol, 1 eq) was added. The mixture was stirred at room temperature for 45 minutes. After the reaction was completed, 10 mL of water was added, and the mixture was extracted with ethyl acetate (10 mL×3). The organic phase was collected, concentrated, and then the next step was performed.

[0032] Under nitrogen atmosphere, compound 2 (1.00 mmol), compound 3 (1.10 mmol, 1.1 eq), palladium acetate (0.05 mmol, 0.05 eq), S-PhOS (0.1 mmol, 0.1 eq) and anhydrous sodium carbonate (5 mmol, 5 eq) were added to a two-necked flask, and a mixed solvent of toluene: water: ethanol = 3:1:1 (6 mL: 2 mL: 2 mL) was added. The mixture was refluxed and stirred at 100 ° C for 12 hours. After the reaction was completed, the reaction was quenched with 10 mL of cold water, extracted three times with dichloromethane (10 mL), and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated through a column (volume ratio, petroleum ether: ethyl acetate = 20:1) to obtain compound 5 (244 mg).

[0033] 1 H NMR (400MHz, CDCl3) δ8.11–8.08(d,1H),8.06(s,1H),7.80(d,J=1.3Hz,1H),7.54(ddd,J=8.3,6. 7,1.4Hz,1H),7.44–7.33(m,4H),7.25–7.15(m,2H),7.08–6.98(m,1H),2.79(s,3H),2.33(s,3H). 13 C{ 1 H}NMR (100MHz, CDCl3) δ135.22,133.34,133.06,133.01,132.65,131.11,129.55,128.35,127.42,126.4 8,125.50,125.28,124.38,121.35,119.73,119.42,113.16,110.21,19.59,12.51.HRMS(ESI)calcd.for C 20 H 17 NNa + ([M+Na] + ):294.1253,found:294.1248. Example 2

[0034] Synthesis of compound 6:

[0035]

[0036] At room temperature, compound 1 (1.00 mmol) and KOH (2.5 mmol, 2.5 eq) were added to a round-bottom flask, and DMF (10 mL) was added to fully dissolve compound 1. After stirring for 20 minutes, a DMF solution (6 mL) of iodine (1.00 mmol, 1 eq) was added and the reaction was continued for 45 minutes. After the reaction was completed, 10 mL of water was added, and the mixture was extracted with ethyl acetate (10 mL×3). The organic phase was collected, concentrated, and then the mixture was transferred to the next step.

[0037] Under nitrogen atmosphere, compounds 2 (1.00 mmol), 4 (1.10 mmol, 1.1 eq), palladium acetate (0.05 mmol, 0.05 eq), S-PhOS (0.1 mmol, 0.1 eq) and anhydrous sodium carbonate (5 mmol, 5 eq) were added to a two-necked flask, and a mixed solvent of toluene: water: ethanol = 3:1:1 (6 mL: 2 mL: 2 mL) was added, and the mixture was refluxed at 100 ° C for 12 hours. After the reaction was completed, the reaction was quenched with 10 mL of cold water, and the organic phase was extracted three times with dichloromethane (10 mL), dried over anhydrous sodium sulfate, and concentrated through a column (volume ratio, petroleum ether: ethyl acetate = 20:1) to obtain compound 6 (240 mg).

[0038] 1 H NMR(400MHz, CDCl3)δ8.00(s,1H),7.75-7.65(m,5H),7.63-7.58(m,2H),7. 47(t,J=7.7Hz,2H),7.36(t,J=7.3Hz,2H),7.21-7.10(m,2H),2.57(s,3H). 13 C{ 1 H}NMR (100MHz, CDCl3) δ141.12,138.54,135.29,134.56,131.58,129.72,128.82,127.86,12 7.24,127.11,127.05,121.63,120.07,118.87,114.13,110.35,12.70.HRMS(ESI)calcd.for C 21 H 18 N + ([M+H] + ):284.1433,found:284.1428.

[0039] Example 3

[0040] This example is a preliminary test process and results of the inhibition of Zika virus cell levels by compounds 5 and 6 described in Examples 1 and 2. The materials and consumables listed in this example can be obtained from commercial channels unless otherwise specified, and the cells and viruses are from the cell and microbial resource library of CTCC or other relevant institutions. The experimental method of this example is a standard molecular biology, cell biology or virology operating procedure, which can be easily understood and operated by researchers in the field. The specific steps are as follows:

[0041] 1. Cells:

[0042] Vero (African green monkey kidney cells), culture conditions: DMEM medium 90% + 10% bovine serum + 1% Penicillin-Streptomycin.

[0043] 2. Viruses

[0044] The Zika virus gene sequence and the Nanoluciferase (NLuc) gene sequence were connected to the plasmid pACYC177 using conventional gene methods to obtain the plasmid pZIKV-NLuc (stored in this laboratory). Cells were inoculated one day in advance to reach 70–90% confluence during transfection. Lipofectamine 3000 was used to TM Prepare plasmid DNA-liposome complexes, and then add the DNA-liposome complexes to cells. After 48 hours, harvest the supernatant and infect Vero cells to obtain the recombinant virus ZIKV-NLuc (for the specific process, please refer to Gao, J.; Chen, J.; Lu, W.; Cai, J.; Shi, L.; Zhao, W.; Zhang, B., Construction of an infectious clone of Zika virus stably expressing an EGFP marker in a eukaryotic expression system. Virology Journal 2021, 18(1).).

[0045] 3. Main reagents:

[0046] DMEM (Gibco, cat:C11995500BT);

[0047] Fetal bovine serum FBS (Gibco, cat: 10270-106);

[0048] Plasmid pACYC177 (Miaoling Biotechnology, cat: P0995);

[0049] Double antibody Pen-Strep (10,000U / mL) (M&C gene biotechnology, cat: G2723M3);

[0050] Anti-Zika virus positive drug: Ribavirin (Solarbio, cat: IR0090);

[0051] Gaussia-Lumi TM Gaussia luciferase reporter gene assay kit (Beyotime, cat: RG072S);

[0052] pZIKV-NLuc transfection reagent Lipofectamine 3000 TM (Invitrogen, Cat:2319757).

[0053] 4. Experimental steps:

[0054] Step 1: If Figure 1 As shown, the compounds inhibited ZIKV replication assay: Vero cells were cultured at 1.5×10 4 cells / well were inoculated in a 96-well plate and cultured at 37°C for 12h; when the cell confluence reached 90-95%, the original culture medium was discarded, 100μL of the compound to be tested (the final concentration of the compound was 5μM) or the positive control drug (Ribavirin, the final concentration was 100μM) was added, and 3 replicate wells were set for each well; incubated at 37°C for 4h, the supernatant was discarded, and ZIKV-NLuc virus dilution (according to MOI=0.01) and the compound to be tested (the final concentration of the compound was 5μM) or the positive control drug (the final concentration was 100μM) were added; incubated at 37°C for 2h, the free virus was washed away, and 100μL of the compound to be tested or the positive control drug was added to make the final concentration of the compound 5μM and the final concentration of the positive control drug 100μM; incubated at 37°C for 48h, 100μL of Gaussia-Lumi TM The detection reagent was used to detect Nano luciferase (NLuc) using a multifunctional microplate reader and read the fluorescence value. The anti-Zika activity was initially screened at a single concentration (5 μM). Figure 2 Where indicated, compound concentration was 5 μM and control drug concentration was 100 μM.

[0055] Step 2: Replace the 5 μM test compound in step 1 with the test compound at a final concentration of 0.04 μM, 0.2 μM, 1 μM, 5 μM, and 25 μM. According to step 1, calculate the relative ZIKV infection nanoluciferase activity = compound fluorescence value / virus control fluorescence value, and then use GraphPad Prism software to obtain the EC for inhibiting virus replication based on the relative ZIKV infection nanoluciferase activity.50 , the results are shown in Figure 3 and Figure 5 ,Depend on Figure 3 It can be seen that the EC of compound 5 50 =8.18μM, by Figure 5 It can be seen that the EC of compound 6 50 =1.367μM.

[0056] The experiment set up three control groups, namely:

[0057] Positive drug group: add virus and Ribavirin with a final concentration of 100 μM;

[0058] Virus infection group: only virus was added without compound;

[0059] Normal cell group: no virus or drug added.

[0060] Step 3: MTT colorimetric assay for cytotoxicity: 1.5×10 4 Each cell was inoculated in a 96-well cell culture plate containing 100 μL of cell culture medium; 100 μL of compound solution with gradient concentration was added to make the final concentrations 1 μM, 5 μM, 25 μM, 50 μM, and 250 μM, respectively; 3 replicates were performed for each concentration; a control without compound was set at the same time; after 48 h of cell culture, 100 μL of supernatant was discarded, 20 μL of MTT (5 mg / mL) was added, and cultured at 37°C for 4 h; centrifugation was performed, 100 μL of supernatant was discarded, 100 μL of DMSO was added, and the mixture was shaken at room temperature in the dark for 15 minutes until the blue formazan dissolved; OD595 was detected by an ELISA instrument, and OD630 was used as the reference wavelength to calculate the cell survival rate, and CC was obtained based on the cell survival rate using GraphPad Prism software 50 , the results are shown in Figure 4 and Figure 6 ,Depend on Figure 4 It can be seen that the CC of compound 5 50 =118.4μM, by Figure 6 It can be seen that the CC50 of compound 6 is 108.7 μM.

[0061] Step 4: Calculation of the drug antiviral activity selectivity index: Selective Index (SI) = CC 50 / EC 50 4. Test results:

[0062] Conclusion: At a concentration of 5 μM, compounds 5 and 6 have a significant inhibitory effect on ZIKV-NLuc recombinant virus. The drug antiviral activity selectivity index SI (Selective Index) is 14.47 and 79.52 respectively (the control drug Ribavirin selectivity index is 75).

[0063] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A 3-arylated indole derivative, characterized in that: At least one of the following structures: 、 。 2. The method for synthesizing the 3-arylated derivative of indole according to claim 1, characterized in that: The steps include: (1) Compound 1 and iodine are used as raw materials, and iodine is added after alkalization with potassium hydroxide to obtain compound 2; (2) Compound 2 reacts with arylboronic acid 3 or 4 in the presence of palladium acetate, S-PhOS ligand and sodium carbonate to obtain the target compound.

3. The method for synthesizing the 3-arylated derivative of indole according to claim 2, characterized in that: In step (1), the molar ratio of compound 1, elemental iodine and potassium hydroxide is 1:1:(2-3).

4. The method for synthesizing the 3-arylated derivative of indole according to claim 2, characterized in that: In step (2), the molar ratio of compound 2, arylboronic acid 3 or 4, palladium acetate, S-PhOS and anhydrous sodium carbonate is 1:(1-1.5):(0.01-0.05):(0.1-0.2):(4-6).

5. The method for synthesizing the 3-arylated derivative of indole according to claim 2, characterized in that: In step (1), the reaction solvent is DMF, and the reaction temperature is room temperature. In step (2), the reaction solvent is a mixed solvent of toluene: water: ethanol = (2-4): 1: 1 in volume ratio, and the reaction temperature is 90-110°C.

6. The method for synthesizing the 3-arylated derivative of indole according to claim 5, characterized in that: In step (1), compound 1 is reacted with potassium hydroxide for 10 to 30 minutes before adding iodine DMF solution; in step (2), the reaction is carried out under nitrogen protection.

7. Use of the 3-arylated indole derivative according to claim 1 in the preparation of antiviral drugs.

8. The use of the 3-arylated derivative of indole according to claim 7 in the preparation of antiviral drugs, characterized in that: The virus is Zika virus.

Images