Dihydroquinoline derivatives and their pharmaceutical use against influenza
By developing a dihydroquinoline derivative to inhibit the Cap-dependent endonuclease PA of influenza virus, the problem of existing anti-influenza drugs being unable to inhibit viral replication has been solved, achieving effective treatment and prevention of influenza virus.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG UNIV QILU HOSPITAL
- Filing Date
- 2023-12-05
- Publication Date
- 2026-06-12
Smart Images
Figure QLYQS_1 
Figure QLYQS_2 
Figure QLYQS_3
Abstract
Description
Technical Field
[0001] This invention belongs to the field of pharmaceuticals, specifically relating to a dihydroquinoline derivative and its pharmaceutical application in the fight against influenza. Background Technology
[0002] Influenza virus (also known as influenza virus) is a representative species of the Orthomyxoviridae family, belonging to the genus Influenzavirus, and is an RNA virus.
[0003] The emergence of new influenza virus subtypes mainly involves changes in hemagglutinin and neuraminidase around the viral envelope, while the RNA polymerase and neuraminidase proteins located in the inner layer are relatively stable and rarely mutate. Therefore, antiviral drugs targeting RNA polymerase are less likely to induce drug resistance.
[0004] The influenza virus RNA-dependent RNA polymerase consists of three subunits: PB1, PB2, and PA. Highly conserved in influenza A, B, and C viruses, it is responsible for viral genome replication and transcription. PB2 uses a "cap snatching" mechanism to capture host cell mRNA, while the N-terminal domain of the PA subunit cleaves this mRNA, exerting endonuclease activity to produce capped oligonucleotides for viral mRNA generation and transcription. Therefore, PA plays a crucial role in influenza virus replication; inhibiting PA activity can effectively suppress influenza virus replication, thereby controlling influenza virus transmission. Thus, cap-dependent endonuclease inhibitors have good potential for treating influenza. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a dihydroquinoline derivative and its pharmaceutical application in anti-influenza.
[0006] The specific technical solution of the present invention is as follows:
[0007] A dihydroquinoline derivative, with the general structural formula (I) as follows:
[0008] in:
[0009] R1 is Halogen atom or H;
[0010] R2 is selected from:
[0011]
[0012] One of them; R3 is a halogen atom or H;
[0013] R4 is either methoxy or H;
[0014] R5 is a halogen atom or H.
[0015] The halogen atom refers to fluorine, chlorine, bromine, or iodine.
[0016] The methoxy group refers to -O-CH3.
[0017] Preferably, R1 is Or I, where R3 is F or H, and R5 is Cl or H.
[0018] Furthermore, the dihydroquinoline derivative is one of the following compounds (1) to (15):
[0019]
[0020]
[0021] The present invention also provides a pharmaceutical composition characterized in that it comprises an effective dose of a dihydroquinoline derivative, its stereoisomer or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, excipient or diluent.
[0022] The present invention further relates to the use of a compound represented by a dihydroquinoline derivative, its stereoisomer or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition thereof in the preparation of a treatment or prevention of a disease caused by a virus having a Cap-dependent endonuclease; wherein the disease is a related disease or symptom caused by an influenza virus, etc.
[0023] The present invention also relates to a method for treating, preventing and / or treating diseases caused by pre-prepared viruses having Cap-dependent endonucleases, comprising administering to a patient a therapeutically effective dose of a compound of general formula (I), its stereoisomer, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition thereof.
[0024] The present invention also provides a method for treating disease conditions using the compounds or pharmaceutical compositions of the present invention, including but not limited to conditions related to diseases caused by viruses having Cap-dependent endonucleases.
[0025] The present invention also relates to a method for treating diseases in mammals caused by viruses having Cap-dependent endonucleases, comprising administering to said mammal a therapeutically effective amount of the compound of the present invention or a pharmaceutically acceptable salt, ester, prodrug, solvate, hydrate or derivative thereof.
[0026] In some implementations, this method relates to diseases or symptoms such as those caused by influenza viruses. The influenza virus is preferably influenza A, influenza B, or influenza C.
[0027] The preferred influenza A viruses are HIN1, HIN2, H2N2, H3N1, H3N2, H3N8, H5N1, H5N2, H5N3, H5N8, H5N9, H7N1, H7N2, H7N3, H7N4, H7N7, H7N9, H9N2, or H1ON7.
[0028] Influenza virus-related diseases or symptoms are preferably accompanied by flu-like symptoms such as fever, chills, headache, muscle pain, and general fatigue, or respiratory tract inflammation such as sore throat, runny nose, nasal congestion, cough, and phlegm, and gastrointestinal symptoms such as abdominal pain, vomiting, and diarrhea, accompanied by complications of secondary infection such as acute encephalopathy and pneumonia.
[0029] Specifically, the applications include, but are not limited to, dihydroquinoline derivatives acting on influenza virus endonucleases to inhibit influenza virus replication.
[0030] The beneficial effects of this invention are as follows: the preparation method of the related compounds of this invention is simple, the yield is stable, and it has good effects on the prevention and treatment of influenza-related diseases; Detailed Implementation
[0031] The invention will now be described through specific implementation schemes.
[0032] Example 1
[0033] The preparation of compound (1) is carried out in the following steps:
[0034] 1. Preparation of 4-(2-chloro-4-fluorobenzyl)aniline
[0035] 2-Chloro-4-fluorobenzyl bromide (22.3 g, 1 eq), 4-nitrophenylboronic acid (16.7 g, 1 eq), tetrakis(triphenylphosphine)palladium (5.78 g, 0.05 eq), and potassium carbonate (13.8 g, 1 eq) were added to a 500 mL three-necked flask, along with 200 mL of 1,4-dioxane and 40 mL of water. The mixture was refluxed at 110 °C for 2 hours under nitrogen protection. TLC confirmed complete reaction of the starting material. The mixture was cooled to room temperature, and 100 mL of ethyl acetate was added with stirring. The mixture was separated, and the upper organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness to obtain a yellow solid. This solid was directly added to the next reaction step based on a 100% yield.
[0036] The above-mentioned yellow solid was dissolved in 400 ml of methanol, 100 ml of water was added, and then reduced iron powder (22.4 g, 4 eq) and ammonium chloride (21.4 g, 4 eq) were added. The mixture was stirred at 55 °C for 12 hours, and TLC confirmed that the starting material had reacted completely. 500 ml of EA and 500 ml of saturated sodium chloride were added, stirred, and separated. The upper organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness to obtain 24 g of solid.
[0037] 2. Preparation of ethyl 6-(2-chloro-4-fluorobenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate
[0038] 23.5 g (1 eq) of 4-(2-chloro-4-fluorobenzyl)aniline was dissolved in 200 mL of diphenyl ether, and then 23.8 g (1.1 eq) of diethyl ethoxymethylene malonate was added. The mixture was reacted at 140 °C for 2 hours, then heated to 240 °C and reacted for 5 hours. TLC confirmed that the reactants had reacted completely, and the mixture was cooled to room temperature. The reaction solution was poured into 500 mL of petroleum ether, and a solid precipitated. The solid was filtered. The obtained solid was added to 500 mL of methanol, refluxed and stirred for 1 hour, cooled to room temperature and filtered. The solid was washed twice with methanol and dried under vacuum at 40 °C to obtain 8.4 g of a gray solid.
[0039] 3. Preparation of Compound (1)
[0040] Ethyl 6-(2-chloro-4-fluorobenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.72 g, 1 eq), 4-fluoro-3-(trifluoromethyl)benzoylmethyl bromide (1.14 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0041] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IA. After purification by silica gel column chromatography, compound IA was obtained.
[0042] Example 2
[0043] The preparation of compound (2) is carried out in the following steps:
[0044] Ethyl 6-(2-chloro-4-fluorobenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.72 g, 1 eq), 7-(4-bromobutoxy)-3,4-dihydro-2(1H)-quinolinone (1.19 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The reaction solution was cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0045] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IB. After purification by silica gel column chromatography, compound IB was obtained.
[0046] Example 3
[0047] The preparation of compound (3) is carried out in the following steps:
[0048] Ethyl 6-(2-chloro-4-fluorobenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.72 g, 1 eq), N-(6-bromohexyl)phthalimide (1.24 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0049] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IC. After purification by silica gel column chromatography, compound IC was obtained.
[0050] Example 4
[0051] The preparation of compound (4) is carried out in the following steps:
[0052] Ethyl 6-(2-chloro-4-fluorobenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.72 g, 1 eq), 4-phenyl-1-butyl bromide (0.85 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0053] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product ID. After purification by silica gel column chromatography, compound ID was obtained.
[0054] Example 5
[0055] The preparation of compound (5) is carried out in the following steps:
[0056] Ethyl 6-(2-chloro-4-fluorobenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.72 g, 1 eq), diphenyl bromide (0.99 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0057] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strongly alkaline with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude IF. After purification by silica gel column chromatography, compound IF was obtained.
[0058] Example 6
[0059] The preparation of compound (6) is carried out in the following steps:
[0060] 1. Preparation of 4-(4-fluoro-3-methoxybenzyl)aniline
[0061] 4-Fluoro-3-methoxybenzyl bromide (21.9 g, 1 eq), 4-nitrophenylboronic acid (16.7 g, 1 eq), tetrakis(triphenylphosphine)palladium (5.78 g, 0.05 eq), and potassium carbonate (13.8 g, 1 eq) were added to a 500 mL three-necked flask, along with 200 mL of 1,4-dioxane and 40 mL of water. The mixture was refluxed at 110 °C for 2 hours under nitrogen protection. TLC confirmed complete reaction of the starting material. The mixture was cooled to room temperature, and 100 mL of ethyl acetate was added with stirring. The mixture was separated, and the upper organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness to obtain a yellow solid. This solid was directly added to the next reaction step based on a 100% yield.
[0062] The above-mentioned yellow solid was dissolved in 400 ml of methanol, 100 ml of water was added, and then reduced iron powder (22.4 g, 4 eq) and ammonium chloride (21.4 g, 4 eq) were added. The mixture was stirred at 55 °C for 12 hours, and TLC confirmed that the starting material had reacted completely. 500 ml of EA and 500 ml of saturated sodium chloride were added, stirred, and separated. The upper organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness to obtain 16 g of solid.
[0063] 2. Preparation of ethyl 6-(4-fluoro-3-methoxybenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid
[0064] 16 g (1 eq) of 4-(4-fluoro-3-methoxybenzyl)aniline was dissolved in 200 mL of diphenyl ether, and then 15 g (1.1 eq) of diethyl ethoxymethylene malonate was added. The mixture was reacted at 140 °C for 2 hours, then heated to 240 °C and reacted for 5 hours. TLC confirmed that the reactants had reacted completely, and the mixture was cooled to room temperature. The reaction solution was poured into 500 mL of petroleum ether, and a solid precipitated. The solid was filtered. The obtained solid was added to 500 mL of methanol, refluxed and stirred for 1 hour, cooled to room temperature and filtered. The solid was washed twice with methanol and dried under vacuum at 40 °C to obtain 5.4 g of a gray solid.
[0065] 3. Preparation of Compound 6
[0066] Ethyl 6-(4-fluoro-3-methoxybenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.71 g, 1 eq), 4-fluoro-3-(trifluoromethyl)benzoylmethyl bromide (1.14 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0067] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IIA. After purification by silica gel column chromatography, compound IIA was obtained.
[0068] Example 7
[0069] The preparation of compound (7) is carried out in the following steps:
[0070] Ethyl 6-(4-fluoro-3-methoxybenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.71 g, 1 eq), 7-(4-bromobutoxy)-3,4-dihydro-2(1H)-quinolinone (1.19 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The reaction solution was cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0071] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude IIB. After purification by silica gel column chromatography, compound IIB was obtained.
[0072] Example 8
[0073] The preparation of compound (8) is carried out in the following steps:
[0074] Ethyl 6-(4-fluoro-3-methoxybenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.71 g, 1 eq), N-(6-bromohexyl)phthalimide (1.24 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0075] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude IIC. After purification by silica gel column chromatography, compound IIC was obtained.
[0076] Example 9
[0077] The preparation of compound (9) is carried out in the following steps:
[0078] Ethyl 6-(4-fluoro-3-methoxybenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.71 g, 1 eq), 4-phenyl-1-butyl bromide (0.85 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0079] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IID. After purification by silica gel column chromatography, compound IID was obtained.
[0080] Example 10
[0081] The preparation of compound (10) is carried out in the following steps:
[0082] Ethyl 6-(4-fluoro-3-methoxybenzyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.71 g, 1 eq), diphenylbromomethane (0.99 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0083] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude IIF. After purification by silica gel column chromatography, compound IIF was obtained.
[0084] Example 11
[0085] The preparation of compound (11) is carried out in the following steps:
[0086] Ethyl 6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.69 g, 1 eq), 4-fluoro-3-(trifluoromethyl)benzoylmethyl bromide (1.14 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0087] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IIIA. After purification by silica gel column chromatography, compound IIIA was obtained.
[0088] Example 12
[0089] The preparation of compound (12) is as follows:
[0090] Ethyl 6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.69 g, 1 eq), 7-(4-bromobutoxy)-3,4-dihydro-2(1H)-quinolinone (1.19 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0091] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IIIB. After purification by silica gel column chromatography, compound IIIB was obtained.
[0092] Example 13
[0093] The preparation of compound (13) is carried out in the following steps:
[0094] Ethyl 6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.69 g, 1 eq), N-(6-bromohexyl)phthalimide (1.24 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0095] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IIIC. After purification by silica gel column chromatography, compound IIIC was obtained.
[0096] Example 14
[0097] The preparation of compound (14) is carried out in the following steps:
[0098] Ethyl 6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.69 g, 1 eq), 4-phenyl-1-butyl bromide (0.85 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0099] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IIID. After purification by silica gel column chromatography, compound IIID was obtained.
[0100] Example 15
[0101] The preparation of compound (15) is carried out in the following steps:
[0102] Ethyl 6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate (0.69 g, 1 eq), diphenylbromomethane (0.99 g, 2 eq), and potassium carbonate (0.55 g, 2 eq) were added to a 100 mL single-necked flask, followed by 10 mL of DMF. The mixture was reacted under nitrogen protection at 80 °C for two hours, and TLC confirmed complete reaction. The mixture was then cooled and poured into 100 mL of water, precipitating a solid. The solid was filtered and washed twice with water.
[0103] The obtained solid was added to a 100ml single-necked flask, followed by 20ml of methanol. The mixture was stirred to dissolve, and the pH was adjusted to strong alkalinity with 4N sodium hydroxide solution. The mixture was stirred at room temperature for 2 hours, and the reaction was confirmed to be complete by TLC. The pH of the reaction solution was adjusted to 3-4 with 2N hydrochloric acid, and then 100ml of water was added. The solid precipitated, and the solid was filtered to obtain crude product IIIF. After purification by silica gel column chromatography, compound IIIF was obtained.
[0104] Example 16
[0105] 1. Cytopathic Effect (CPE) Assay
[0106] The influenza virus strain A / Hongkong / 8 / 68(H3N2) was selected for testing, with baloxavir as the control compound. MDCK cells were seeded at a certain density in microplates and cultured at 37°C in a 5% CO2 incubator for 24 hours. Different concentration gradients of the test compound and active virus strain were added, setting up cells (without virus infection) and virus-infected controls. The final concentration of DMSO in cell culture was 0.5%. After culturing the cells at 37°C in a 5% CO2 incubator for 5 days, cytopathic effects were observed, and the inhibition rate of the compound against influenza virus at different concentrations was calculated.
[0107] 2. Evaluation of intracellular compound toxicity in MDCK cells
[0108] After culturing MDCK cells in 96-well cell culture plates for 24 hours, different concentrations of the test compound or control solution were added. After incubation at 37°C for 48 hours, a mixture of MTT and PBS solution was added. After incubation at 37°C for 4 hours, a lysing solution was added to dissolve the crystals formed and lyse the cells. Finally, the CC50 value of the compound was calculated by measuring the absorbance at 620 nm wavelength using an ELISA reader.
[0109] 3. In vitro activity screening results
[0110] In vitro activity tests were conducted on compounds from series B and C. The results showed that compound 12 exhibited the best inhibitory activity against influenza virus, with inhibition rates of 14.51% and 39.65% at 10 μM and 50 μM, respectively. Compounds with halogen substitution at the side chain position on the benzene ring showed better activity than those with benzyl substitution. Furthermore, elongation of the side chain at the nitrogen atom was detrimental to improving the compound's activity; when the side chain length exceeded 5 carbon atoms, the compound struggled to maintain its antiviral activity.
Claims
1. A dihydroquinoline derivative, characterized in that, The structure is as follows: ,in: R1 is , hydrogen atoms or halogen atoms; R2 is: ， R3 is a halogen atom or H; R4 is either methoxy or H; R5 is a halogen atom or H.
2. A dihydroquinoline derivative as described in claim 1, characterized in that, R1 is Or I, where R3 is F or H, and R5 is Cl or H.
3. A dihydroquinoline derivative as described in claim 1 or 2, characterized in that, It is one of the following compounds (2), (7), (12): 。 4. A pharmaceutical composition, characterized in that, Includes a dihydroquinoline derivative or a pharmaceutically acceptable salt thereof as described in claim 1 or 2, and a pharmaceutically acceptable carrier or diluent.
5. The use of the dihydroquinoline derivative according to any one of claims 1-3 in the preparation of a medicament for the prevention or treatment of influenza-related diseases.
6. The application as described in claim 5, characterized in that, The dihydroquinoline derivative according to any one of claims 1-3 acts on influenza virus endonuclease to inhibit influenza virus replication.