A benz[g]indole derivative and use thereof in the preparation of an anti-dengue drug

Abstract

This invention discloses compounds as shown in Formula 1 and their pharmaceutically acceptable salts, as well as their preparation methods and applications. As shown in Figure 2, the compounds as shown in Formula 1 and their pharmaceutically acceptable salts can be used to prepare antiviral drugs or drugs for treating dengue fever. The compounds as shown in Formula 1 provided by this invention exhibit good anti-dengue virus activity and low cytotoxicity, significantly inhibiting DENV1-4 at a concentration of 1 μM, especially at the cellular level against DENV-2 EC. 50 It can reach 2.12 nM, exhibiting stronger antiviral activity. Furthermore, compound 1's C2C... 50 At concentrations greater than 200 μM, the toxicity to host cells is lower. Compound 1 of this invention exhibits higher safety and a therapeutic window, and has the potential to be used in the preparation of anti-dengue virus drugs, possessing significant value for widespread application.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to benzo[g]indole derivatives and their application in the preparation of anti-dengue fever drugs. Background Technology

[0002] Dengue fever (DF) is a vector-borne infectious disease caused by dengue virus (DENV). DENV is a single-stranded positive-sense RNA virus belonging to the Flaviviridae family, with four serotypes (DENV-1, DENV-2, DENV-3, and DENV-4). Clinical manifestations of dengue fever range from mild fever to life-threatening dengue hemorrhagic fever / shock syndrome, with a mortality rate exceeding 20% ​​in severe cases. Currently, there are no effective antiviral drugs for dengue virus. The marketed vaccine Dengvaxia® carries the risk of antibody-dependent enhancement (ADE), limiting its widespread use. Clinical treatment heavily relies on supportive therapies such as antipyretics and fluid replacement. Some broad-spectrum antiviral drugs have a low half-maximal inhibitory concentration (IC50) against DENV. 50 The concentration of the drug is >10μM and it has serious side effects such as hemolytic anemia.

[0003] The inhibitory or preventive effects of existing small molecule drugs against dengue virus are highly uncertain, and they also suffer from problems such as high cytotoxicity and low antiviral activity. Therefore, the search for small molecule compounds with good efficacy against dengue virus has significant clinical application value. Summary of the Invention

[0004] The purpose of this invention is to provide a small molecule compound that has a good inhibitory effect on dengue virus, thereby exerting its efficacy in combating viral infection.

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

[0006] A benzo[g]indole derivative, chemically represented by Formula 1 below, or a pharmaceutically acceptable salt of a compound represented by Formula 1:

[0007] .

[0008] The compound shown in Formula 1 is named (S)-2-amino-3-(3-(((3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methoxy)carbonyl)phenyl)propionic acid.

[0009] The present invention also provides the use of benzo[g]indole derivatives of Formula 1 and their pharmaceutically acceptable salts in the preparation of antiviral drugs.

[0010] The virus mentioned includes dengue virus.

[0011] Furthermore, the dengue virus includes one or more of the dengue virus types DENV-1, DENV-2, DENV-3, and DENV-4.

[0012] Preferably, the antiviral effect is at least one of the following: inhibiting dengue virus replication; inhibiting dengue virus infection of cells.

[0013] The present invention also provides the use of benzo[g]indole derivatives of Formula 1 and their pharmaceutically acceptable salts in the preparation of medicaments for treating dengue fever.

[0014] The present invention also provides a pharmaceutical composition for treating dengue virus or dengue fever, the pharmaceutical composition comprising benzo[g]indole derivatives of Formula 1 and their pharmaceutically acceptable salts, and may also include pharmaceutically acceptable carriers to form pharmaceutical preparations such as tablets, capsules, powders, syrups, suspensions, injections, etc.; and may also include commonly used pharmaceutical excipients such as sweeteners, diluents, and fillers.

[0015] The pharmaceutical composition may also include other anti-dengue active ingredients.

[0016] The present invention also provides a method for preparing the benzo[g]indole derivative shown in Formula 1, wherein the reaction formula of the method is shown below:

[0017] ;

[0018] ;

[0019] ;

[0020] .

[0021] Furthermore, the method includes the following steps:

[0022] (1) At 0~5℃, 2-(4-chloro-2-methoxyphenyl)acetic acid as shown in Formula 1-1 is added to thionyl chloride, and then the mixture is stirred at 60~70℃ for 1~3 hours to obtain 2-(4-chloro-2-methoxyphenyl)acetyl chloride as shown in Formula 1-2;

[0023] (2) Dissolve the 1H-benzo[g]indole shown in Formula 1-5 in N,N-dimethylformamide, add sodium hydride and p-toluenesulfonyl chloride (54.7 g, 0.29 mol) to the solution at 0~5℃, stir the reaction at room temperature for 1~2 hours to obtain the 1-p-toluenesulfonyl-1H-benzo[g]indole shown in Formula 1-6;

[0024] The molar ratio of 1H-benzo[g]indole, sodium hydride, and p-toluenesulfonyl chloride is 1:2~3:1.2~1.5;

[0025] (3) Dissolve 1-p-toluenesulfonyl-1H-benzo[g]indole as shown in Formula 1-6 in 1,2-dichloroethane, add titanium tetrachloride and 2-(4-chloro-2-methoxyphenyl)acetyl chloride as shown in Formula 1-2 to the solution at 0-5°C, stir the reaction at room temperature for 4-5 hours to obtain 2-(3-chloro-5-methoxyphenyl)-1-(1-p-toluenesulfonyl-1H-benzo[g]indole-3-yl)ethane-1-one as shown in Formula 1-7;

[0026] The molar ratio of 1-p-toluenesulfonyl-1H-benzo[g]indole (as shown in Formulas 1-6), titanium tetrachloride, and 2-(4-chloro-2-methoxyphenyl)acetyl chloride (as shown in Formula 1-2) is 1:2~2.5:1.5~2.

[0027] (4) 2-(3-chloro-5-methoxyphenyl)-1-(1-p-toluenesulfonyl-1H-benzo[g]indol-3-yl)ethane-1-one as shown in Formula 1-7 and tetrabutylammonium fluoride were reacted in tetrahydrofuran solvent at a temperature of 65-70°C for 2-3 hours to prepare 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)ethane-1-one as shown in Formula 1-8;

[0028] The molar ratio of 2-(3-chloro-5-methoxyphenyl)-1-(1-p-toluenesulfonyl-1H-benzo[g]indol-3-yl)ethane-1-one and tetrabutylammonium fluoride shown in Formulas 1-7 is 1:3~4;

[0029] (5) The 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)ethane-1-one shown in Formula 1-8 is dissolved in tetrahydrofuran solvent. Phenylated trimethylammonium tribromide is added to the solution at 0~5℃. After the addition is complete, the mixture is stirred at room temperature for 4~5 hours to obtain the 1-(1H-benzo[g]indol-3-yl)-2-bromo-2-(3-chloro-5-methoxyphenyl)ethane-1-one shown in Formula 1-9.

[0030] The molar ratio of 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)ethane-1-one and phenyltrimethylammonium tribromide shown in Formulas 1-8 is 1:2~3;

[0031] (6) The 1-(1H-benzo[g]indol-3-yl)-2-bromo-2-(3-chloro-5-methoxyphenyl)ethane-1-one, 3-methoxy-5-(methanesulfonyl)aniline, and diisopropylethylamine shown in Formulas 1-9 are reacted in acetonitrile solvent at 90-95°C for 15-20 hours with stirring to obtain the 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)ethane-1-one shown in Formulas 1-10;

[0032] The molar ratio of 1-(1H-benzo[g]indol-3-yl)-2-bromo-2-(3-chloro-5-methoxyphenyl)ethane-1-one, 3-methoxy-5-(methylsulfonyl)aniline, and diisopropylethylamine shown in Formulas 1-9 is 1:1.2~1.5:2~2.5;

[0033] (7) Under nitrogen protection, (S)-3-(3-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionic acid, di-tert-butyl dicarbonate, and 4-dimethylaminopyridine, as shown in Formula 1-11, are dissolved in tert-butanol solvent and reacted at room temperature for 15-20 hours to obtain (S)-3-(3-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionic acid tert-butyl ester, as shown in Formula 1-12.

[0034] The molar ratio of (S)-3-(3-bromophenyl)-2-((tert-butyloxycarbonyl)amino)propionic acid, ditert-butyl dicarbonate, and 4-dimethylaminopyridine shown in Formula 1-11 is 1:1.3~1.6:0.1~0.2;

[0035] (8) The tert-butyl propionate (S)-3-(3-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionate, triethylamine, and 1,1-bis(diphenylphosphine)ferrocene palladium dichloride shown in Formula 1-12 are dissolved in methanol solvent and reacted at 70-80°C for 15-20 hours under a carbon monoxide atmosphere to obtain the methyl benzoate (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate shown in Formula 1-13;

[0036] The molar ratio of (S)-3-(3-bromophenyl)-2-((tert-butyloxycarbonyl)amino)propionate, triethylamine, and 1,1-bis(diphenylphosphine)ferrocene palladium dichloride shown in Formula 1-12 is 1:4~5:0.2~0.3;

[0037] (9) Methyl benzoate (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate shown in Formula 1-13 was dissolved in a mixed reaction solvent of tetrahydrofuran, methanol and water in a volume ratio of 1:1:1. Anhydrous lithium hydroxide was added under stirring, and the reaction was stirred at room temperature for 1-2 hours to obtain (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid shown in Formula 1-14.

[0038] The molar ratio of (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate and anhydrous lithium hydroxide shown in Formula 1-13 is 1:2~3;

[0039] (10) The (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid shown in Formula 1-14 is dissolved in dichloromethane, and sodium bicarbonate, chloromethyl chlorosulfonate and tetrabutylammonium hydrogen sulfate are added at 0~5℃. The reaction is carried out at room temperature for 15~20 hours to obtain the (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid chloromethyl ester shown in Formula 1-15;

[0040] The molar ratio of (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid, sodium bicarbonate, chloromethyl chlorosulfonate, and tetrabutylammonium hydrogen sulfate shown in Formula 1-14 is 1:10~12:2~2.5:0.2~0.3;

[0041] (11) Chloromethyl benzoate of formula 1-15 (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate, 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)ethane-1-one of formula 1-10, potassium iodide, and cesium carbonate in solvent N,N In dimethylformamide, the reaction is carried out at room temperature for 15-20 hours to obtain (3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methyl 3-((S)-3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate as shown in Formula 1-16;

[0042] The molar ratio of 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)ethane-1-one shown in Formula 1-10, (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate chloromethyl ester shown in Formula 1-15, potassium iodide, and cesium carbonate is 1:3~4:2~2.5:3~4;

[0043] (12) The (3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methyl 3-((S)-3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate and trifluoroacetic acid shown in Formula 1 are reacted in dichloromethane solvent at room temperature for 2-3 hours to obtain the (S)-2-amino-3-(3-(((3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methoxy)carbonyl)phenyl)propionic acid shown in Formula 1.

[0044] The beneficial effects of this invention are as follows:

[0045] The compound of Formula 1 provided by this invention exhibits good anti-dengue virus activity and low cytotoxicity. It significantly inhibits DENV1-4 at a concentration of 1 μM, especially at the cellular level, reaching the half-maximal effective concentration (EC50) against DENV-2. 50 The concentration reached 2.12 nM, superior to the micromolar levels reported in existing technologies, demonstrating stronger antiviral activity. Furthermore, compound 1 showed a half-maximal cytotoxicity concentration (MCC) of 2.12 nM. 50 Compound 1 has a selectivity index (SI=CC) greater than 200 μM, resulting in lower toxicity to host cells. 50 / EC 50 The SI value reaches 90,000 to 100,000, which is much higher than the SI level of existing anti-dengue compounds (usually between 10 and 100). Compound 1 of the present invention has higher safety and therapeutic window, and has the potential to be used to prepare anti-dengue virus drugs, and has great value for promotion and application. Attached Figure Description

[0046] Figure 1 The dose-inhibition rate curve of compound 1 against DENV2 dengue virus serotype and the dose-survival rate curve against Vero cells are shown.

[0047] Figure 2 The structural formula of the benzo[g]indole derivative shown in Formula 1 is given. Detailed Implementation

[0048] The technical solution of 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 thereto.

[0049] Example 1: Synthesis of Compound 1

[0050] The reaction formula is shown below:

[0051] ;

[0052] ;

[0053] .

[0054] 1. Synthesis of 2-(4-chloro-2-methoxyphenyl)acetyl chloride (intermediates 1-2)

[0055] At 0 °C, 55.0 g (0.27 mol) of 2-(4-chloro-2-methoxyphenyl)acetic acid was added in portions to 250 mL of thionyl chloride. After the addition was complete, the mixture was stirred at 60 °C for 2 hours. The reaction solution was then concentrated to obtain a colorless oily 2-(4-chloro-2-methoxyphenyl)acetyl chloride (67.0 g, purity: 90.0%, yield: 100.0%). LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5 μm, 4.6*30 mm, ESI+): m / z = 215.1 [M+1] + (MS signal of methyl ester was detected by methanol quenching).

[0056] 2. Synthesis of N,N-dimethyl-2-(1-nitronaphth-2-yl)vinyl-1-amine (intermediates 1-4)

[0057] 2-Methyl-1-nitronaphthalene (200.0 g, 1.07 mol) was dissolved in N,N-dimethylformamide (1.5 L), followed by the addition of N,N-dimethylformamide dimethyl acetal (255.0 g, 2.14 mol). The mixture was stirred at 120 °C for 24 hours. The reaction solution was concentrated under reduced pressure, and the crude product was slurried in petroleum ether (300 mL). The mixture was filtered to obtain a filter cake, which was then dried under reduced pressure to obtain a red solid, N,N-dimethyl-2-(1-nitronaphthalene-2-yl)ethylene-1-amine (240.0 g, purity: 85.0%, yield: 92.7%). This product was used directly in the next step. LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5 μm, 4.6*30 mm, ESI+): m / z = 216.1 [M-26]+ .

[0058] 3. Synthesis of 1H-benzo[g]indole (intermediates 1-5)

[0059] N,N-Dimethyl-2-(1-nitronaphth-2-yl)ethylene-1-amine (190.0 g, 0.78 mol) was dissolved in a 5 / 1 mixture of anhydrous ethanol and water (2 L). Then, iron powder (218.99 g, 3.92 mol) and ammonium chloride (251.68 g, 4.7 mol) were added to the solution at 25°C. After the addition was complete, the mixture was stirred at 80°C for 4 hours. Liquid chromatography-mass spectrometry (LC-MS) showed the raw materials had disappeared. The reaction solution was filtered through diatomaceous earth. The filter cake was washed with a 10 / 1 mixture of dichloromethane and methanol until no product was found in the filter cake. The filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (PE / DCM = 5 / 1-1 / 1) to obtain a yellow solid 1H-benzo[g]indole (55.0 g, purity: 90.5%, yield: 41.9%).

[0060] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 168.1[M+H] + ;

[0061] 1 H NMR (400 MHz, DMSO) d 6) δ 12.01 (s, 1H), 8.36 (d, J = 8.4 Hz, 1H), 7.91 (d, J = 8.0 Hz, 1H), 7.67 (d, J = 8.4 Hz, 1H), 7.52 (t, J = 7.2 Hz, 1H), 7.45– 7.37 (m, 3H), 6.59 (s, 1H).

[0062] 4. Synthesis of 1-p-toluenesulfonyl-1H-benzo[g]indole (intermediates 1-6)

[0063] 1H-benzo[g]indole (40.0 g, 0.24 mol) was dissolved in N,N-dimethylformamide (400 mL), and then sodium hydride (60%, 11.5 g, 0.48 mol) and p-toluenesulfonyl chloride (54.7 g, 0.29 mol) were added to the solution at 0 °C. After the addition was complete, the mixture was stirred at 25 °C for 1 hour. Liquid chromatography-mass spectrometry (LC-MS) showed that the starting material had disappeared. The reaction solution was poured into ice water (1.5 L), and then extracted with ethyl acetate (500 mL * 3). The resulting organic phase was washed successively with water (200 mL * 3) and saturated brine (300 mL). The organic phase was then dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (PE:EA = 10 / 1-3 / 1) to give a yellow solid 1-p-toluenesulfonyl-1H-benzo[g]indole (85.0 g, purity: 95.0%, yield 99.2%).

[0064] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 321.9[M+H] + ;

[0065] 1 H NMR (400 MHz, DMSO) d 6) δ 8.96 (d, J = 8.4 Hz, 1H), 8.02 (d, J = 3.6 Hz, 1H), 7.98 (d, J = 8.0 Hz, 1H), 7.75 (q, J = 8.8 Hz, 2H), 7.62 (d, J = 8.4 Hz, 2H), 7.56 (t, J = 7.6 Hz, 1H), 7.47 (t, J = 7.6 Hz, 1H), 7.30 (d, J = 8.0 Hz, 2H), 7.06(d, J = 3.6 Hz, 1H), 2.25 (s, 3H).

[0066] 5. Synthesis of 2-(3-chloro-5-methoxyphenyl)-1-(1-p-toluenesulfonyl-1H-benzo[g]indol-3-yl)ethane-1-one (intermediates 1-7)

[0067] 1-Toluenesulfonyl-1H-benzo[g]indole (85.0 g, 0.26 mol) was dissolved in 1,2-dichloroethane (400 mL). Then, titanium tetrachloride (100.0 g, 0.53 mol) and 2-(4-chloro-2-methoxyphenyl)acetyl chloride (86.6 g, 0.40 mol) were added to the solution at 0 °C. After the addition was complete, the mixture was stirred at 25 °C for 4 hours. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the starting material had disappeared. The reaction solution was poured into ice water (1 L), and then extracted with dichloromethane (500 mL*3). The resulting organic phase was washed successively with water (500 mL) and saturated brine (500 mL). The organic phase was then dried with anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (PE:EA=100 / 1-5 / 1) to obtain a yellow solid 2-(3-chloro-5-methoxyphenyl)-1-(1-p-toluenesulfonyl-1H-benzo[g]indol-3-yl)ethane-1-one (106.0 g, purity: 90.0%, yield 79.6%).

[0068] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 504.0[M+H] + ;

[0069] 1 H NMR (400 MHz, DMSO) d 6) δ 9.03 (s, 1H), 8.89 (d, J = 8.8 Hz, 1H), 8.35 (d, J = 8.8 Hz, 1H), 8.00 (d, J = 7.6 Hz, 1H), 7.87 (d, J = 8.8 Hz, 1H), 7.81 (d, J =8.4 Hz, 2H), 7.57 (t, J = 7.6 Hz, 1H), 7.51 (t, J = 7.6 Hz, 1H), 7.39 (d, J = 8.0Hz, 2H), 7.30 (d, J = 8.0 Hz, 1H), 7.12 (d, J = 1.6 Hz, 1H), 7.06 – 7.00 (m, 1H), 4.41 (s, 2H), 3.79 (s, 3H), 2.30 (s, 3H).

[0070] 6. Synthesis of 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)ethane-1-one (intermediates 1-8)

[0071] 2-(3-chloro-5-methoxyphenyl)-1-(1-p-toluenesulfonyl-1H-benzo[g]indol-3-yl)ethane-1-one (65.0 g, 0.13 mol) was dissolved in tetrahydrofuran (600 mL), and then tetrabutylammonium fluoride (1 mol / L in THF, 386.0 mL, 0.39 mol) was added to the solution at 25 °C. After the addition was complete, the mixture was stirred at 65 °C for 2 hours. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the starting material had disappeared. The reaction solution was poured into ice water (1 L), and then extracted with ethyl acetate (500 mL*3). The resulting organic phase was washed successively with water (200 mL) and saturated brine (300 mL). The organic phase was then dried with anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (PE:EA=20 / 1-1 / 1) to obtain a yellow solid 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)ethane-1-one (39.5 g, purity: 93.0%, yield 87.7%).

[0072] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 348.0[MH] - ;

[0073] 1 H NMR (400 MHz, DMSO) d 6) δ 12.83 (s, 1H), 8.50 (d, J = 3.2 Hz, 1H), 8.43 (d, J = 8.0 Hz, 1H), 8.25 (d, J = 8.4 Hz, 1H), 7.97 (d, J = 8.4 Hz, 1H), 7.64- 7.58 (m, 2H), 7.50 - 7.46 (m, 1H), 7.24 (d, J = 8.4 Hz, 1H), 7.07 (d, J = 2.0Hz, 1H), 6.98 (dd, J = 8.0, 1.6 Hz, 1H), 4.25 (s, 2H), 3.76 (s, 3H).

[0074] 7. Synthesis of 1-(1H-benzo[g]indol-3-yl)-2-bromo-2-(3-chloro-5-methoxyphenyl)ethane-1-one (intermediates 1-9)

[0075] 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)ethane-1-one (40.0 g, 0.11 mol) was dissolved in tetrahydrofuran (400 mL), and then phenyltrimethylammonium tribromide (85.9 g, 0.22 mol) was added to the solution at 0 °C. After the addition was complete, the mixture was stirred at 25 °C for 4 hours. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the starting material had disappeared. The reaction solution was poured into ice water (1 L), and then extracted with ethyl acetate (300 mL * 3). The resulting organic phase was washed successively with water (200 mL) and saturated brine (200 mL). The organic phase was then dried with anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (PE:DCM=100 / 1-1 / 1) to obtain a yellow solid 1-(1H-benzo[g]indol-3-yl)-2-bromo-2-(3-chloro-5-methoxyphenyl)ethane-1-one (30.4 g, purity: 84.2%, yield 62.0%).

[0076] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 426.0, 428[MH] - ;

[0077] 1 H NMR (400 MHz, DMSO) d 6) δ 12.98 (s, 1H), 8.43 (d, J = 3.2 Hz, 1H), 8.39 (d, J = 8.0 Hz, 1H), 8.26 (d, J = 8.4 Hz, 1H), 7.99 (d, J = 8.0 Hz, 1H), 7.69(d, J = 8.8 Hz, 1H), 7.63 - 7.59 (m, 2H), 7.50 (t, J = 8.0 Hz, 1H), 7.15 (d, J =1.6 Hz, 1H), 7.08 (dd, J= 8.4, 2.0 Hz, 1H), 6.96 (s, 1H), 3.91 (s, 3H).

[0078] 8. Synthesis of 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)ethane-1-one (intermediates 1-10)

[0079] 1-(1H-benzo[g]indol-3-yl)-2-bromo-2-(3-chloro-5-methoxyphenyl)ethane-1-one (21.0 g, 49.0 mmol) was dissolved in acetonitrile (400 mL). Then, 3-methoxy-5-(methanesulfonyl)aniline (11.8 g, 58.8 mmol) and diisopropylethylamine (12.7 g, 98.0 mmol) were added to the solution at 25 °C. After the addition was complete, the mixture was stirred at 90 °C for 16 hours. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the starting material had disappeared. The reaction solution was poured into ice water (1 L), and then extracted with ethyl acetate (300 mL * 3). The resulting organic phase was washed successively with water (200 mL) and saturated brine (200 mL). The organic phase was then dried with anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (PE:DCM = 100 / 1-1 / 1). The crude product was then slurried and filtered with acetonitrile (60 mL) to obtain a filter cake. The filter cake was dried to obtain a yellow solid 1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)ethane-1-one (4.3 g, purity: 95.5%, yield 15.9%).

[0080] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 547.0[MH] - ;

[0081] 1 H NMR (400 MHz, DMSO) d 6) δ 12.95 (s, 1H), 8.50 (d, J = 3.2 Hz, 1H), 8.38 (d, J = 8.4 Hz, 1H), 8.28 (d, J = 8.8 Hz, 1H), 7.97 (d, J = 8.4 Hz, 1H), 7.67(d, J= 8.8 Hz, 1H), 7.60 (t, J = 6.8 Hz, 1H), 7.49 (t, J = 6.8 Hz, 1H), 7.39 (d, J = 8.0 Hz, 1H), 7.14 (d, J = 2.0 Hz, 1H), 7.11 (d, J = 8.0 Hz, 1H), 6.98 (dd, J =8.4, 2.0 Hz, 1H), 6.95 (s, 1H), 6.64 (s, 1H), 6.60 (s, 1H), 6.34 (d, J = 8.0Hz, 1H), 4.04 (s, 3H), 3.73 (s, 3H), 3.10 (s, 3H).

[0082] 9. Synthesis of (S)-3-(3-bromophenyl)-2-((tert-butyloxycarbonyl)amino)propionate tert-butyl ester (intermediates 1-12)

[0083] (S)-3-(3-bromophenyl)-2-((tert-butyloxycarbonyl)amino)propionic acid (formula 1-11) (3.00 g, 0.0087 mol) was dissolved in tert-butanol (30 mL) under nitrogen protection. Di-tert-butyl dicarbonate (2.47 g, 0.013 mol) and 4-dimethylaminopyridine (0.11 g, 0.00087 mol) were added to the reaction solution, and the reaction was carried out at room temperature for 16 hours. Liquid chromatography-mass spectrometry (LC-MS) showed that the starting material had disappeared. Water (50 mL) was added to the reaction solution, and the mixture was extracted with ethyl acetate (50 mL x 3). The combined organic phases were washed with water and brine (50 mL), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 5 / 1) to give a white solid (S)-3-(3-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionate tert-butyl ester (3 g, purity: 93.68%, yield: 80.46%).

[0084] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 244.1[M-156] + .

[0085] 10. Synthesis of (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate (intermediate 1-13)

[0086] 3.00 g (0.0075 mol) of tert-butyl (S)-3-(3-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionate was dissolved in methanol (50 mL), and triethylamine (3.04 g, 0.03 mol) and 1,1-bis(diphenylphosphine)ferrocene palladium dichloride (1.09 g, 0.0015 mol) were added. The mixture was stirred at 70 °C for 16 hours under a carbon monoxide atmosphere. The starting material disappeared as determined by liquid chromatography-mass spectrometry. The reaction mixture was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 20 / 1) to give a yellow oily substance, methyl (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate (2.6 g, purity: 93.74%, yield: 85.33%).

[0087] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 224.3[M-156] + .

[0088] 11. Synthesis of (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid (intermediate 1-14)

[0089] Methyl (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate (1 g, 0.0026 mol) was dissolved in a 1 / 1 / 1 mixture of tetrahydrofuran / methanol / water (10 mL). Anhydrous lithium hydroxide (0.12 g, 0.0052 mol) was added with stirring, and the mixture was stirred at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS) showed the starting material had disappeared. The pH of the reaction mixture was adjusted to 4 with 1 N hydrochloric acid, and the mixture was extracted with ethyl acetate (20 mL x 3). The combined organic phases were washed successively with water and saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: dichloromethane / methanol = 10 / 1) to give yellow oily (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid (360 mg, purity: 85.01%, yield: 30.77%).

[0090] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 364.2[M-1] - .

[0091] 12. Synthesis of (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)chloromethyl benzoate (intermediate 1-15)

[0092] (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoic acid (240 mg, 0.65 mmol) was dissolved in dichloromethane (5 mL). Sodium bicarbonate (550.25 mg, 6.55 mmol), chloromethyl chlorosulfonate (216.14 mg, 1.31 mmol), and tetrabutylammonium hydrogen sulfate (44.48 mg, 0.13 mmol) were added at 0 °C, and the reaction was carried out at 25 °C for 16 hours. The starting material disappeared as determined by liquid chromatography-mass spectrometry. The reaction mixture was poured into water (20 mL) and extracted with ethyl acetate (20 mL x 3). The combined organic phases were washed with saturated brine (20 mL), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel preparation plate (PE:EA=1 / 1) to obtain (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)chloromethyl benzoate (150 mg, purity: 82.94%, yield: 45.79%).

[0093] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 258[M-156] + .

[0094] 13. Synthesis of (3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methyl 3-((S)-3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate (intermediate 1-16)

[0095] (S)-3-(3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)chloromethyl benzoate (Formula 1-15) (150 mg, 0.36 mmol) and (S)1-(1H-benzo[g]indol-3-yl)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)ethane-1-one (Formula 1-10) (59.54 mg, 0.10 mmol) were dissolved in N,N-dimethylformamide (5 mL), and potassium iodide (35.98 mg, 0.21 mmol) and cesium carbonate (117.78 mg, 0.36 mmol) were added. The reaction mixture was reacted at 25 °C for 16 hours. Liquid chromatography-mass spectrometry (LC-MS) showed that the starting material had disappeared. The reaction mixture was poured into water (10 mL), extracted with ethyl acetate (10 mL x 3), and the organic phases were combined. The organic phase was washed with brine (50 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. Purification was achieved by silica gel plate preparation (PE:EA = 1 / 1) to give a yellow solid (3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methyl 3-((S)-3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate (110 mg, purity: 47.3%, yield 15.5%).

[0096] 14. Synthesis of (S)-2-amino-3-(3-(((3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methoxy)carbonyl)phenyl)propionic acid (Compound 1)

[0097] (3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methyl 3-((S)-3-(tert-butoxy)-2-((tert-butoxycarbonyl)amino)-3-oxopropyl)benzoate (110 mg, 0.11 mmol) was dissolved in dichloromethane (2 mL), cooled to 0 °C, and trifluoroacetic acid (2 mL) was added. The mixture was then heated to 25 °C and reacted for 2 hours. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the starting material had disappeared. The crude product was concentrated under reduced pressure and purified by high pressure to obtain a white solid (S)-2-amino-3-(3-(((3-((S)-2-(3-chloro-5-methoxyphenyl)-2-((3-methoxy-5-(methanesulfonyl)phenyl)amino)acetyl)-1H-benzo[g]indol-1-yl)methoxy)carbonyl)phenyl)propionic acid (20.3 mg, purity: 69.78%, yield: 21.50%).

[0098] LCMS (Agilent Technologies, 1260 HPLC and 6120 MSD, Excsep, 5μm, 4.6*30mm, ESI+): m / z = 770.1[M+H] + ;

[0099] 1 H NMR (400 MHz, DMSO) d 6) δ 8.80 (s, 1H), 8.63 - 8.51 (m, 1H), 8.40 -8.32 (m, 1H), 8.10 - 8.02 (m, 1H), 7.93 - 7.86 (m, 1H), 7.75 - 7.70 (m, 3H),7.60 - 7.50 (m, 2H), 7.45 - 7.32 (m, 2H), 7.22 - 7.14 (m, 2H), 7.01 - 6.90(m, 2H), 6.87 - 6.76 (m, 1H), 6.66 - 6.57 (m, 2H), 6.37 - 6.26 (m, 1H), 4.13(s, 3H), 3.73 (s, 3H), 3.68 - 3.58 (m, 1H), 3.24 - 3.03 (m, 5H), 2.18 - 2.90 (m, 2H), 2.98 - 2.90 (m, 1H).

[0100] Example 2: Pharmacological evaluation of compound 1

[0101] Vero cells were cultured in DMEM medium at 37°C, 5% CO2, and 5% FBS. 48-well plates were used, with a growth rate of 2 × 10⁶ cells / well. 5 Cells were seeded at a density of 200 μL of cell suspension per well. Subsequent experiments were performed when cells reached 80% confluence. Compound 1 was serially diluted with 2% FBS in DMEM medium, creating 6-8 concentration gradients. The medium was aspirated, and 120 μL / well of the compound was added and incubated for 1 h. Blank control wells and virus control wells (containing 2% FBS in DMEM medium) were also prepared. Drug cytotoxicity was assessed using the MTT assay, dose-survival curves were plotted, and the half-maximal cytotoxic concentration (MCC) was calculated. 50 ).

[0102] The dengue virus was diluted with 2% FBS in DMEM medium to a concentration of 5 × 10⁻⁶, according to the virus titer determined in Experiment 1. 5 Inoculate 40 μL / well with diluted virus at PFU / ml (MOI = 0.3) and incubate at 37°C for 2 hours. Two replicates are set for each drug concentration, and the mixture is incubated for another 48 hours. After 48 hours, collect the supernatant and add it to the lysis wells of the Vazyme Virus DNA / RNA Extraction Kit 2.0 (Prepackaged) RM501 kit. Run the RM501 program. After the program completes, aspirate RNA from the elution wells for direct qRT-PCR detection, or store at -20°C. Perform qRT-PCR detection using the Vazyme Hiscript II One Step qRT-PCR SYBR Green Kit according to the manufacturer's instructions. Process the qRT-PCR results using Design and Analysis software, plot a standard curve, and export the viral copy number of each well to an Excel spreadsheet. Calculate the inhibition rate of the compound against the virus in each well using the formula in Excel: Inhibition rate = 1 - Virus copy number in the compound well / Virus copy number in the virus well. A dose-inhibition rate (DIR) curve was constructed using GraphPad Prism software: the logarithm of the compound concentration was used as the X-axis, and the corresponding viral inhibition rate was used as the Y-axis. An S-curve was fitted, and the half-maximum effective concentration (EC50) of the compound was calculated. 50 value.

[0103] The dose-inhibition rate curve of compound 1 against DENV2 dengue virus serotype and the dose-survival rate curve against Vero cells are shown in the figure. Figure 1 As shown, Figure 1 The EC shows 50 It is 2.12nm, CC 50 Greater than 200 μM, SI greater than 90000.

[0104] Compound 1 inhibits dengue virus replication in different serotypes. 50 (Vero cells) are shown in Table 1 below:

[0105] Table 1. EC50 of Compound 1 on the inhibition of dengue virus replication in different serotypes 50 (Vero cell) datasheet

[0106]

[0107] Figure 1 The results in Table 1 indicate that compound 1 has superior anti-dengue virus efficacy (EC). 50 Reaching nM levels), with low cytotoxicity (CC). 50>200 μM). Compared with other existing anti-dengue virus compounds, most reported median effective concentrations (EC50) are significantly lower. 50 At the micromolar level, compound 1 exhibited stronger antiviral activity. Furthermore, the half-maximal cytotoxic concentration (MCC) of compound 1 was significantly lower. 50 Compound 1 exhibits significantly higher selectivity than existing small molecule compounds, lower toxicity to host cells, and a selectivity index (SI=CC). 50 / EC 50 The number of cells reached over 90,000, far exceeding existing technology reports, indicating significant clinical potential.

Claims

1. A benzo[g]indole derivative having the chemical formula shown in Formula 1 below, or a pharmaceutically acceptable salt of a compound of Formula 1: 。 2. The use of the benzo[g]indole derivative as shown in Formula 1 and its pharmaceutically acceptable salt as described in claim 1 in the preparation of an anti-dengue virus drug, wherein the dengue virus is one or more of dengue virus types DENV-1, DENV-2, DENV-3 and DENV-4.

3. The application as described in claim 2, characterized in that... The anti-dengue virus is used to inhibit dengue virus replication and / or inhibit dengue virus infection of cells.

4. The use of the benzo[g]indole derivative of Formula 1 as described in claim 1 and its pharmaceutically acceptable salt in the preparation of a dengue fever treatment.

5. A pharmaceutical composition for treating dengue virus or dengue fever, said pharmaceutical composition comprising a benzo[g]indole derivative of Formula 1 as claimed in claim 1 and a pharmaceutically acceptable salt thereof.

6. The method for preparing the benzo[g]indole derivative as shown in Formula 1 according to claim 1, characterized in that... The reaction formula for the method is as follows: 。

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