A class of compounds targeting SARS-Cov-2 3CLpro and their uses

Abstract

The present invention discloses a compound targeting coronavirus 3CLpro or a pharmaceutically acceptable salt or isomer thereof as shown in the general formula I: 1 Selected from hydrogen, R 2 Selected from hydrogen, 4-tert-butylphenyl R 3 Selected from hydrogen, R 4 The compound is selected from hydrogen, and the SARS-Cov-2 virus 3CLpro enzyme inhibition activity test is performed on the compound, and the compound has inhibitory activity against 3CLpro. The present invention also discloses the use of the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salts and isomers in the preparation of 3CLpro inhibitors. The present invention also discloses the use of the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salts and isomers in the preparation of drugs for treating related diseases caused by coronavirus infection.

Description

Technical Field

[0001] The present invention relates to a class of compounds targeting SARS-Cov-2 3CLpro and uses thereof. Background Art

[0002] In 2019, the outbreak caused by the novel coronavirus (SARS-Cov-2) swept the world. SARS-Cov-2 belongs to the genus Betacoronavirus and is an RNA virus. Similar to other coronaviruses, SARS-Cov-2 has an overall spherical structure with the crown surrounding the surface. The SARS-Cov-2 genome encodes two polyproteins, pp1a and pp1ab, and four structural proteins. When a person is infected, SARS-Cov-2 enters the host cell by binding the spike protein to angiotensin-converting enzyme 2 (ACE2) on the cell surface. After the virus enters the host cell, it releases the nucleocapsid and the viral genome. The open reading frame 1a (ORF1a) and open reading frame 1b (ORF1b) of the viral genome are translated into two polyproteins pp1a and pp1ab by the ribosomes of the host cell, respectively.

[0003] ORF1a encodes two proteases, papaya-like cysteine ​​protease (PLpro) and 3C-like cysteine ​​protease (3CLpro, also known as main protease, M pro). These two proteases can specifically cleave polyproteins pp1a and pp1ab to produce 16 mature non-structural proteins for SARS-Cov-2 genome transcription and replication.

[0004] SARS-Cov-2's 3CLpro is a cysteine ​​protease consisting of about 300 amino acids, containing three domains, and its catalytic dyad consists of His41 and Cys145. 3CLpro can specifically recognize and cleave 11 of the 14 cleavage sites of the polyproteins pp1a and pp1ab. Therefore, 3CLpro plays an indispensable role in the entire life cycle of SARS-Cov-2. Inhibition of 3CLpro can stop the replication and life cycle of the virus. It is worth noting that the amino acid sequence of 3CLpro is highly similar in different coronaviruses. The amino acid sequence similarity of SARS and SARS-Cov-2 3CLpro is as high as 96%. In addition to SARS, 3CLpro is also highly conserved in Middle East Respiratory Syndrome Coronavirus (MERS) and SARS-Cov-2 variants. Therefore, 3CLpro is highly conserved in coronaviruses. In theory, all SARS-Cov-2 variants should be inhibited by 3CLpro inhibitors. Surprisingly, no known human protease has similar cleavage specificity. Therefore, 3CLpro has attracted much attention and has become a promising and attractive target for the development of SARS-Cov-2 drugs.

[0005] Although vaccines against SARS-Cov-2 have been developed and widely administered, the virus is constantly mutating and the vaccines may still become ineffective. In the treatment of SARS-Cov-2, a variety of effective drugs are needed to supplement the vaccines.

[0006] Since Cys145 of 3CLpro is a nucleophilic residue, it can form a covalent bond with the electrophilic warhead. So far, a large number of 3CLpro inhibitors have been reported. They are mainly divided into covalent inhibitors (Covalent inhibitors of 3Clpro) and non-covalent inhibitors (Noncovalent inhibitors of 3CLpro). Representative covalent inhibitors reported include Nirmatrelvir (Compound 1) and Dihydromyricetin (Compound 2), and representative non-covalent inhibitors include Ensitrelvir (Compound 3) and Compound 4. Although Nirmatrelvir combined with ritonavir developed by Pfizer has been approved by the FDA as Paxlovid, due to its complex drug-drug interactions, Paxlovid is not suitable for all SARS-Cov-2 infected people. Peptidomimetic inhibitors similar to Nirmatrelvir also have problems in DMPK (drug metabolism and pharmacokinetics), such as low oral bioavailability. Ensitrelvir, developed by Shionogi & Co. Ltd., is effective in inhibiting SARS-Cov-2 and its variants; however, the Japanese Ministry of Health, Labor and Welfare has delayed its approval due to the possible teratogenicity risk. Therefore, it is necessary to find 3CLpro inhibitors with novel skeletons to treat SARS-Cov-2 infected persons.

[0007] Summary of the invention

[0008] The purpose of the present invention is to develop a small molecule inhibitor targeting SARS-Cov-2 3CLpro with excellent activity and a novel skeleton, and use it in the treatment of related diseases caused by infection with new coronaviruses such as SARS-Cov-2, such as new coronavirus infection. The inventors conducted virtual screening by constructing a pharmacophore model of 3CLpro based on a receptor-ligand complex and a molecular docking method, thereby discovering a potential skeleton that has an inhibitory effect on 3CLpro. By further modifying and optimizing the molecular scaffold, the designed compound was organically synthesized to obtain the target compound. The target compound was subjected to a SARS-Cov-2 virus 3CLpro enzyme inhibitory activity experiment, and after preliminary biological activity evaluation, the target compound had inhibitory activity against 3CLpro.

[0009] A compound targeting coronavirus 3CLpro for medical use, having a structure as shown in general formula I, or a pharmaceutically acceptable salt or isomer thereof:

[0010]

[0011] Among them, R 1 Selected from hydrogen, phenyl

[0012] R 2 Selected from hydrogen, 4-tert-Butylphenyl

[0013] R 3 Selected from hydrogen,

[0014] R 4 Selected from hydrogen,

[0015] Preferably, R 1 Selected from

[0016] R 2 Selected from hydrogen,

[0017] R 3 Selected from

[0018] R 4 Selected from hydrogen,

[0019] More preferably, R 1 Selected from

[0020] R 2 Selected from hydrogen,

[0021] R 3 Selected from

[0022] R 4 Selected from hydrogen,

[0023] Specifically, the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salt or isomer is selected from the compounds with the following structures:

[0024]

[0025]

[0026] Another object of the present invention is to provide the use of the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salt or isomer in the preparation of 3CLpro inhibitors.

[0027] Another object of the present invention is to provide the use of the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salts and isomers in the preparation of drugs for treating related diseases caused by coronavirus infection.

[0028] The coronavirus described is the new coronavirus (SARS-Cov-2), SARS, and Middle East Respiratory Syndrome Coronavirus (MERS).

[0029] Another object of the present invention is to provide the use of the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salt or isomer in the preparation of a drug for treating novel coronavirus infection caused by SARS-Cov-2.

[0030] Another object of the present invention is to provide a pharmaceutical composition, which comprises the compound targeting coronavirus 3CLpro or its pharmaceutically acceptable salts and isomers as active ingredients and pharmaceutically acceptable excipients. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below through specific implementation methods.

[0032] Example 1: Synthesis of compound Ben-1

[0033]

[0034] Step 1: Synthesis of compound 6

[0035] Compound 5 (10 mmol), 4-tert-butylaniline (15 mmol), palladium acetate (0.05 mmol), S-Phos (0.1 mmol) and cesium carbonate (20 mmol) were added to anhydrous toluene (40 mL), and the reaction was stirred at 100° C. overnight under argon protection; after the reaction was completed, the reaction solution was cooled to room temperature and filtered through diatomaceous earth; the filtrate was concentrated and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 50:1 V / V) to obtain a yellow oil (compound 6, 808 mg, 24.7%).

[0036] 1 H NMR (300 MHz, CDCl 3)δ10.92(s,1H),8.63-8.30(m,1H),7.60(td,J=7.7,1.9Hz,1H),7.27(dd,J=6.8,1.8Hz,2H),7.19(dt,J=8.0,1.1Hz,1H),7 .04(ddd,J=7.5,5.0,1.2Hz,1H),6.91-6.80(m,2H),6.26(s,1H),4.21(q,J=7.1Hz,2H),1.29(s,9H),1.12(t,J=7.1Hz,3H).

[0037] Step 2: Synthesis of compound 7

[0038] Compound 6 (2.2 mmol, 732 mg) was dissolved in acetic acid. Sodium borohydride (6.6 mmol) was slowly added at 15°C. After the addition, the reaction was stirred at room temperature and monitored by TLC. After 30 min of reaction, the reaction was completed. The acetic acid was neutralized with saturated sodium bicarbonate solution and extracted with ethyl acetate three times. The organic phases were combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The mixture was concentrated under reduced pressure and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 40: 1 V / V) to obtain a yellow oil (compound 7, 481.3 mg, 67.1%).

[0039] 1 H NMR (300 MHz, CDCl 3 )δ8.55(ddd,J=4.9,1.9,0.9Hz,1H),7.55(td,J=7.7,1.9Hz,1H),7.31-6.93(m,4H),6.85-6.27(m,2H),4.66 (s,1H),4.47(t,J=6.5Hz,1H),4.13(q,J=7.1Hz,2H),3.36-3.13(m,2H),1.24(s,9H),1.16(t,J=7.1Hz,3H).

[0040] Step 4: Synthesis of compound 8

[0041] Compound 7 (437.1 mg, 1.3 mmol) was dissolved in methanol, sodium hydroxide (10 mmol) and a small amount of water were added, and the reaction was stirred at room temperature; after the reaction was completed, HCl / 1,4-Dioxane (1,4-dioxane solution) (4 mol / L) was used to adjust the pH to 2; the reaction liquid was evaporated to obtain a solid. The above solid was dispersed in dichloromethane, EDCI (1.95 mmol), HOBT (2.6 mmol), and triethylamine (2.6 mmol) were added, and the reaction was stirred at room temperature; after the reaction was completed, it was concentrated, separated and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 V / V) to obtain a yellow oil (compound 8, 250 mg, 51.6%).

[0042] 1 H NMR (300 MHz, Acetone-d 6 )δ9.32(s,1H),8.56(ddd,J=4.8,1.8,0.9Hz,1H),7.68(td,J=7.7,1.8Hz,1H),7.64-7.58(m,2H),7.48(dt,J=7.9,1.1Hz,1H),7. 31-7.15(m,3H),7.16-7.06(m,2H),7.05-6.98(m,1H),6.65-6.57(m,2H),5.06(t,J=6.7Hz,1H),3.03-2.85(m,2H),1.20(s,9H).

[0043] Step 5: Synthesis of compound Ben-1

[0044] Compound 8 (250 mg, 0.67 mmol) and triethylamine (1.34 mmol) were dissolved in dichloromethane, and a dichloromethane solution of acryloyl chloride (0.67 mmol) was slowly added dropwise under an ice bath; after the addition, the reaction was stirred at room temperature. After the reaction was completed, the mixture was concentrated under reduced pressure and separated and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 V / V) to obtain a yellow solid (compound Ben-1, 100 mg, 36.3%).

[0045] 1 H NMR (300 MHz, CDCl 3)δ8.53-8.46(m,2H),7.68(td,J=7.7,1.8Hz,1H),7.58(d,J=7.9Hz,1H),7.46(d,J=7.9Hz,2H),7.32-7.15(m,5H),7.10-6.99( m,1H),6.89-6.81(m,2H),6.55-6.22(m,2H),6.09-5.82(m,1H),5.51(dd,J=10.3,2.1Hz,1H),3.73-2.81(m,2H),1.29(s,9H).

[0046] Example 2: Synthesis of Compound Ben-2

[0047]

[0048] According to the synthesis method of compound Ben-1 in Example 1, only the amount of compound 5 and the like was replaced with 2-bromo-3-(2-thienyl)-2-ethyl propenoate to obtain 369 mg of a yellow solid (compound Ben-2) with a yield of 53.3%.

[0049] 1 H NMR (300 MHz, CDCl 3 )δ9.10(s,1H),7.63-7.55(m,2H),7.35-7.30(m,4H),7.21-7.07(m,2H),6.97-6.89(m,3H),6.89-6.83(m,1H), 6.46(dd,J=16.8,2.0Hz,1H),5.97(dd,J=16.8,10.3Hz,1H),5.65-5.50(m,2H),3.57-2.98(m,2H),1.34(s,9H).

[0050] Example 3: Synthesis of compound Ben-3

[0051]

[0052] According to the synthesis method of compound Ben-1 in Example 1, only the amount of compound 5 and the like was replaced with 2-bromo-3-(2-thiazolyl)-2-ethyl propenoate to obtain 389.2 mg of a yellow solid (compound Ben-3) with a yield of 44.8%.

[0053] 1 H NMR (300 MHz, CDCl 3)δ9.18(s,1H),7.70(d,J=3.3Hz,1H),7.59-7.56(m,2H),7.40-7.29(m,4H),7.20(d,J=3.3Hz,1H),7.10(t,J=7.3Hz,1H),7.0 4-6.96(m,2H),6.45(dd,J=16.8,2.0Hz,1H),6.04-5.89(m,2H),5.58(dd,J=10.3,2.0Hz,1H),3.53-3.23(m,2H),1.33(s,9H).

[0054] Example 4: Synthesis of Compound Ben-4

[0055]

[0056] According to the synthesis method of compound Ben-1 in Example 1, only the amount of compound 5 and the like was replaced with 2-bromo-3-(2-benzofuranyl)-2-ethyl propenoate to obtain 407.3 mg of a yellow solid (compound Ben-4) with a yield of 36.3%.

[0057] 1 H NMR (300 MHz, CDCl 3 )δ9.06(s,1H),7.58-7.55(m,2H),7.49-7.46(m,1H),7.42-7.30(m,5H),7.24-7.17(m,2H),7.15-7.08(m,1H), 6.96(d,J=8.1Hz,2H),6.48-6.42(m,2H),6.00-5.84(m,2H),5.60-5.56(m,1H),3.33-3.02(m,2H),1.32(s,9H).

[0058] Example 5: Synthesis of Compound A1

[0059]

[0060] Using m-chloroaniline as raw material, compound 10 was obtained according to the literature (European Journal of Medicinal Chemistry, 92 (2015) 178-190).

[0061] Compound 10 was stirred in a trifluoroacetic acid / dichloromethane (1:10 V / V) system at room temperature and the reaction was monitored by TLC. After the reaction was completed, it was neutralized with a saturated sodium bicarbonate solution; extracted with dichloromethane three times, the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a white solid, which was directly subjected to the next step without purification.

[0062] The above white solid (555 mg, 3 mmol) and Et 3 N (2eq, 6mmol) was dissolved in dichloromethane; a dichloromethane solution of acryloyl chloride (3mmol) was added dropwise under ice bath conditions; after the addition was complete, the reaction was stirred at room temperature. After the reaction was complete, silica gel column chromatography (dichloromethane: methanol = 30: 1 V / V) was performed to purify the mixture to obtain a white solid compound A1 (353mg, 49.2%).

[0063] 1 H NMR (300 MHz, DMSO-d 6 )δ10.25(s,1H),8.50(t,J=5.8Hz,1H),7.80(t,J=2.0Hz,1H),7.46(dt,J=8.4,1.4Hz,1H),7.33(t,J=8.1Hz,1H),7.10(dd ,J=8.0,2.3Hz,1H),6.43-6.28(m,1H),6.12(dd,J=17.1,2.2Hz,1H),5.63(dd,J=10.1,2.2Hz,1H),3.99(d,J=5.8Hz,2H).

[0064] Example 6: Synthesis of Compound A2

[0065]

[0066] The amount of acryloyl chloride and other substances in Example 5 was replaced by chloroacetyl chloride, and other conditions remained unchanged to obtain compound A2 as a white solid, 582.1 mg, with a yield of 73.4%.

[0067] 1 H NMR (300 MHz, DMSO-d 6 )δ10.21(s,1H),8.56(t,J=5.8Hz,1H),7.79(s,1H),7.45(d,J=8.2Hz,1H),7 .33(t,J=8.0Hz,1H),7.10(d,J=7.8,1H),4.18(s,2H),3.96(d,J=5.7Hz,2H).

[0068] Example 7: Synthesis of Compound A3

[0069]

[0070] Only the amount of m-chloroaniline and other substances in Example 5 was replaced by p-chloroaniline, and other conditions remained unchanged, to obtain compound A3 as a white solid, 393.6 mg, with a yield of 54.9%.

[0071] 1 H NMR (300 MHz, DMSO-d 6 )δ10.18(s,1H),8.48(t,J=5.9Hz,1H),7.62(d,J=8.9Hz,2H),7.40-7.31(m,2H),6.36(dd,J=17. 1,10.2Hz,1H),6.12(dd,J=17.1,2.2Hz,1H),5.62(dd,J=10.1,2.2Hz,1H),3.99(d,J=5.8Hz,2H).

[0072] Example 8: Synthesis of Compound A4

[0073]

[0074] The amount of m-chloroaniline and other substances in Example 5 was replaced by p-chloroaniline, and the amount of acryloyl chloride and other substances was replaced by chloroacetyl chloride, and other conditions remained unchanged to obtain compound A4 as a white solid, 467.1 mg, with a yield of 59.6%.

[0075] 1 H NMR (300 MHz, DMSO-d 6 )δ10.16(s,1H),8.55(t,J=5.7Hz,1H),7.61(d,J=8.9Hz,2H),7.35(d,J=8.9Hz,2H),4.17(s,2H),3.96(d,J=5.7Hz,2H).

[0076] Example 9: Synthesis of Compound C1

[0077]

[0078] Step 1: Synthesis of compound 11

[0079] Benzaldehyde (10 mmol) and p-chloroaniline (10 mmol) were dissolved in DCE (1,2-dichloroethane). Sodium triacetoxyborohydride (15 mmol) was slowly added thereto under an ice bath. After the addition was completed, the reaction was stirred at room temperature. After the reaction was completed, dichloromethane was added to dilute the reaction solution, and sodium hydroxide solution was added to quench the reaction. The liquids were separated, and the organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 100: 1 V / V) to obtain a white solid (Compound 11, 2.1759 g, 99.8%).

[0080] 1 H NMR (300 MHz, CDCl 3)δ7.38-7.22(m,5H),7.15-7.06(m,2H),6.59-6.50(m,2H),4.30(s,2H),4.06(s,1H).

[0081] Step 2: Synthesis of compound 12

[0082] Under ice bath conditions, bromoacetyl bromide (6.75 mmol) was added dropwise to a mixed solution of compound 11 (4.5 mmol) and potassium carbonate (9 mmol) in dichloromethane. After the addition was completed, the reaction was continued under ice bath conditions. After the reaction was completed, the mixture was filtered, and the filtrate was concentrated under reduced pressure. The mixture was separated and purified by silica gel column chromatography (petroleum ether: ethyl acetate = 30:1 V / V) to obtain a white solid (compound 12, 1.3253 g, 86.9%).

[0083] 1 H NMR (300 MHz, CDCl 3 )δ7.36-7.27(m,5H),7.21-7.13(m,2H),7.05-6.96(m,2H),4.87(s,2H),3.68(s,2H).

[0084] Step 3: Synthesis of compound 13

[0085] Compound 12 (5 mmol) and 2-aminomethylpyridine (7.5 mmol) were dissolved in acetonitrile, potassium carbonate (10 mmol) was added, and the reaction was stirred at room temperature overnight. After the reaction was completed, the filtrate was concentrated under reduced pressure and separated and purified by silica gel column chromatography (dichloromethane: methanol = 30: 1 V / V) to obtain a yellow oil (compound 13, 573.1 mg, 31.3%).

[0086] 1 H NMR (300 MHz, CDCl 3 )δ8.51(d,J=4.7Hz,1H),7.61(td,J=7.7,1.8Hz,1H),7.32-7.27(m,2H),7.26-7.23(m,4H),7 .21-7.09(m,3H),6.87(d,J=8.2Hz,2H),4.86(s,2H),3.87(s,2H),3.17(s,2H),2.19(s,1H).

[0087] Step 4: Synthesis of compound C1

[0088] To a dichloromethane solution of compound 13 (1.56 mmol) and triethylamine (3.12 mmol) was added a dichloromethane solution of acryloyl chloride (2.34 mmol) dropwise under ice bath conditions. After the addition was complete, the reaction was stirred at room temperature. After the reaction was completed, the reaction was concentrated under reduced pressure and purified by silica gel column chromatography (dichloromethane: methanol = 40: 1 V / V) to give a colorless oil (compound C1, 450 mg, 68.8%).

[0089] 1 H NMR (300 MHz, CDCl 3 )δ8.83-8.12(m,1H),7.72-7.50(m,1H),7.42-7.07(m,9H),7.07-6.84(m,2H) ,6.71-6.17(m,2H),5.92-5.51(m,1H),5.11-4.52(m,4H),4.24-3.61(m,2H).

[0090] Example 10: Synthesis of Compound B1

[0091]

[0092] The amount of compound 11 and other substances in Example 9 was replaced by benzylamine to obtain compound B1, a colorless oily liquid, 435.3 mg, with a yield of 54.2%.

[0093] 1 H NMR (300 MHz, CDCl 3 )δ10.80-8.62(m,1H),7.98-7.52(m,2H),7.34-7.18(m,6H),7.12-6.98(m,1H),6.54-6 .30(m,2H),5.74-5.56(m,1H),4.79-4.65(m,2H),4.51-4.40(m,2H),4.25-4.20(m,2H).

[0094] Example 11: Synthesis of Compound B2

[0095]

[0096] The amount of compound 11 in Example 9 was replaced by benzylamine, and the equivalent amount of 2-aminomethylpyridine was replaced by 3-aminomethylpyridine to obtain compound B2 as a colorless oily liquid, 247.5 mg, with a yield of 50.1%.

[0097] 1 H NMR (300 MHz, CDCl 3)δ8.56-8.45(m,2H),7.64-7.52(m,1H),7.34-7.17(m,6H),7.05-6.83(m,1H),7.62-7. 35(m,2H),5.80-5.74(m,1H),4.77-4.63(m,2H),4.41-4.39(m,2H),4.03-3.80(m,2H).

[0098] Example 12: Synthesis of Compound C2

[0099]

[0100] The 2-aminomethylpyridine in Example 9 was replaced by 3-aminomethylpyridine to obtain compound C2 as a colorless oily liquid, 853.5 mg, with a yield of 75.2%.

[0101] 1 H NMR (300 MHz, CDCl 3 )δ8.55-8.50(m,1H),8.46-8.40(m,1H),7.65-7.50(m,1H),7.30-7.06(m,8H),7.01-6. 75(m,2H),6.62-6.32(m,2H),5.78-5.70(m,1H),4.86-4.69(m,4H),3.78-3.70(m,2H).

[0102] Example 13: Synthesis of Compound C3

[0103]

[0104] Using 3-thiophenecarboxaldehyde, p-chloroaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of 3-thiophenecarboxaldehyde to replace the benzaldehyde in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C3 was obtained as a colorless oily liquid, 855.7 mg, with a yield of 55.8%.

[0105] 1 H NMR (300 MHz, CDCl 3 )δ8.56-8.50(m,1H),8.45-8.34(m,1H),7.65-7.50(m,1H),7.33-7.20(m,4H),7.03-6. 07(m,4H),6.62-6.31(m,2H),5.78-5.69(m,1H),4.84-4.68(m,4H),3.75-3.69(m,2H).

[0106] Example 14: Synthesis of Compound C4

[0107]

[0108] Using phenylacetaldehyde, p-chloroaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, an equal amount of phenylacetaldehyde was used to replace the benzaldehyde in step 1 of Example 9, and an equivalent amount of 3-aminomethylpyridine was used to replace the 2-aminomethylpyridine in step 3 of Example 9 to obtain compound C4, a colorless oily liquid, 610.7 mg, with a yield of 44.0%.

[0109] 1 H NMR (300 MHz, CDCl 3 )δ8.55-8.34(m,2H),7.63-7.49(m,1H),7.37-7.31(m,2H),7.29-7.20(m,4H),7.18-7.14(m,2H),7.10-6.82(m,2H) ,6.62-6.22(m,2H),5.77-5.68(m,1H),4.78-4.64(m,2H),3.92-3.86(m,2H),3.74-3.63(m,2H),2.91-2.80(m,2H).

[0110] Example 15: Synthesis of Compound C5

[0111]

[0112] Using p-phenylbenzaldehyde, p-chloroaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of p-phenylbenzaldehyde to replace the benzaldehyde in Step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in Step 3 of Example 9, compound C5 was obtained as a white solid, 669.5 mg, with a yield of 46.5%.

[0113] 1 H NMR (300 MHz, CDCl 3 )δ8.55-8.42(m,1H),7.67-7.14(m,14H),7.07-6.81(m,2H),6.63-6.35(m,2H),5.78-5.71(m,1H),4.90-4.70(m,4H),3.80-3.73(m,2H).

[0114] Example 16: Synthesis of Compound C6

[0115]

[0116] Using cyclohexylcarboxaldehyde, p-chloroaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of cyclohexylcarboxaldehyde to replace the benzaldehyde in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C6 was obtained as a colorless oily liquid, 514 mg, with a yield of 48.3%.

[0117] 1 H NMR (300 MHz, CDCl 3 )δ8.63-8.34(m,2H),7.68-7.47(m,1H),7.45-7.34(m,2H),7.32-6.96(m,3H),6.63-6.27(m,2H) ,5.79-5.66(m,1H),4.89-4.57(m,2H),3.77-3.67(m,2H),3.59-3.42(m,2H),1.88-0.68(m,11H).

[0118] Example 17: Synthesis of Compound C7

[0119]

[0120] Using p-fluorobenzaldehyde, p-chloroaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of p-fluorobenzaldehyde to replace the benzaldehyde in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C7 was obtained as a colorless oily liquid, 408.7 mg, with a yield of 44.4%.

[0121] 1 H NMR (300 MHz, CDCl 3 )δ8.55-8.49(m,1H),8.46-8.40(m,1H),7.66-7.52(m,1H),7.33-7.21(m,3H),7.17-7.04(m,2H) ,7.01-6.76(m,4H),6.62-6.31(m,2H),5.78-5.69(m,1H),4.82-4.68(m,4H),3.77-3.71(m,2H).

[0122] Example 18: Synthesis of Compound C8

[0123]

[0124] Using p-chlorobenzaldehyde, benzylamine and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of p-chlorobenzaldehyde to replace the benzaldehyde in step 1 of Example 9, using an equal amount of benzylamine to replace the p-chloroaniline in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C8 was obtained as a colorless oily liquid, 751 mg, and the yield was 38.5%.

[0125] 1 H NMR (300 MHz, CDCl 3 )δ8.69-8.27(m,2H),7.82-7.47(m,1H),7.43-6.95(m,10H),6.67-6.08(m,2H),5.93-5 .61(m,1H),5.04-4.66(m,2H),4.63-4.53(m,2H),4.47-4.32(m,2H),4.26-4.00(m,2H).

[0126] Example 19: Synthesis of Compound C9

[0127]

[0128] Using benzaldehyde, p-tert-butylaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of p-tert-butylaniline to replace the p-chloroaniline in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C9 was obtained as a colorless oily liquid, 584.2 mg, and the yield was 44.6%.

[0129] 1 H NMR (300 MHz, CDCl 3 )δ8.56-8.47(m,1H),8.46-8.40(m,1H),7.71-7.47(m,1H),7.40-7.09(m,8H),7.04-6.72(m,2H) ,6.66-6.26(m,2H),5.87-5.57(m,1H),4.91-4.53(m,4H),3.94-3.65(m,2H),1.71-0.15(m,9H).

[0130] Example 20: Synthesis of Compound C10

[0131]

[0132] Using benzaldehyde, isobutylamine and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of isobutylamine to replace the p-chloroaniline in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C10 was obtained as a colorless oily liquid, 623 mg, with a yield of 50.2%.

[0133] 1 H NMR (300 MHz, CDCl 3 )δ8.64-8.27(m,2H),7.80-7.46(m,1H),7.45-7.03(m,6H),6.69-6.11(m,2H),5.83-5.54(m,1H) ,4.91-4.38(m,4H),4.28-3.92(m,2H),3.39-2.80(m,2H),2.05-1.91(m,1H),1.01-0.73(m,6H).

[0134] Example 21: Synthesis of Compound C11

[0135]

[0136] Using benzaldehyde, p-phenylaniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of p-phenylaniline to replace the p-chloroaniline in step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in step 3 of Example 9, compound C11 was obtained as a white solid, 764.1 mg, with a yield of 47.3%.

[0137] 1 H NMR (300 MHz, CDCl 3 )δ8.54-8.43(m,2H),7.67-7.50(m,5H),7.46-7.34(m,3H),7.31-7.20(m,5H),7.19-6. 90(m,3H),6.62-6.32(m,2H),5.76-5.70(m,1H),4.92-4.71(m,4H),3.89-3.70(m,2H).

[0138] Example 22: Synthesis of Compound C12

[0139]

[0140] Using p-chlorobenzaldehyde, aniline and 3-aminomethylpyridine as raw materials, referring to the synthesis method of Example 9, using an equal amount of p-chlorobenzaldehyde to replace the benzaldehyde in Step 1 of Example 9, using an equal amount of aniline to replace the p-chloroaniline in Step 1 of Example 9, using an equivalent amount of 3-aminomethylpyridine to replace the 2-aminomethylpyridine in Step 3 of Example 9, compound C12 was obtained as a colorless oily liquid, 823.4 mg, with a yield of 54.4%.

[0141] 1 H NMR (300 MHz, CDCl 3 )δ8.54-8.49(m,1H),8.45-8.39(m,1H),7.66-7.62(m,1H),7.38-7.14(m,7H),7.13-6. 85(m,3H),6.59-6.34(m,2H),5.77-5.70(m,1H),4.84-4.67(m,4H),3.80-3.73(m,2H).

[0142] Example 23: Synthesis of Compound C13

[0143]

[0144] Using benzaldehyde, p-chloroaniline and 2-benzothiazolemethylamine as raw materials, according to the synthesis method of Example 9, using an equivalent amount of 2-benzothiazolemethylamine to replace 2-aminomethylpyridine in step 3 of Example 9, compound C13 was obtained as a light yellow solid, 673.2 mg, with a yield of 75.2%.

[0145] 1 H NMR (300 MHz, CDCl 3 )δ7.99-7.92(m,1H),7.83-7.81(m,1H),7.50-7.43(m,1H),7.40-7.33(m,1H),7.30-7.18(m,6H),7.17-6.91(m,3H) ,6.70-6.46(m,1H),6.46-6.27(m,1H),5.79-5.72(m,1H),5.14-5.04(m,2H),4.87-4.80(m,2H),3.99-3.96(m,2H).

[0146] Example 24: Synthesis of Compound C14

[0147]

[0148] Using benzaldehyde, p-chloroaniline and 3-aminomethylthiophene as raw materials, according to the synthesis method of Example 9, using an equivalent amount of 3-aminomethylthiophene to replace 2-aminomethylpyridine in step 3 of Example 9, compound C14 was obtained as a colorless oily liquid, 739.7 mg, with a yield of 91.8%.

[0149] 1 H NMR (300 MHz, CDCl 3 )δ7.31-7.21(m,6H),7.19-7.09(m,2H),7.05-7.94(m,3H),6.90-6.71(m,1H),6.65-6. 31(m,2H),5.74-5.65(m,1H),4.86-4.80(m,2H),4.76-4.68(m,2H),3.82-3.70(m,2H).

[0150] Example 25: Inhibition rate determination experiment of target small molecules

[0151] A commercial kit based on fluorescence resonance energy transfer (FRET) (Enhanced 2019-nCoV Mpro / 3CLpro Inhibitor Screening Kit, Catalog No.: P0315S, Beyotime Biotech) was used to detect the inhibitory activity of 24 compounds of the present invention on SARS-CoV-23CLpro. Ebselen was selected as a positive control. The test compound was dissolved in DMSO and diluted to the corresponding concentration using DMSO. The test was performed according to the instructions of the kit. The kit utilizes the ability of SARS-Cov-2 3CLpro to hydrolyze specific FRET substrates and release quenched fluorescent groups, and fluorescence detection can be performed at excitation and emission wavelengths of 325 and 393 nm. In the presence of a 3CLpro-specific inhibitor, the enzyme loses its inhibitory activity, resulting in a decrease in fluorescence intensity.

[0152] Table 1. SARS-CoV-2 virus 3CLpro enzyme inhibitory activity of the compounds of the present invention

[0153] compound number suppression Ben-1 44%(100μM) Ben-2 26%(100μM) Ben-3 55%(100μM) Ben-4 20%(100μM) A1 35%(10μM) A2 16%(10μM) A3 28%(10μM) A4 26%(10μM) B1 37% (10μM) B2 53%(10μM) C1 52%(10μM) C2 72%(10μM) C3 48%(10μM) C4 41%(10μM) C5 33%(10μM) C6 38%(10μM) C7 44%(10μM) C8 38%(10μM) C9 48%(10μM) C10 18%(10μM) C11 43%(10μM) C12 50%(10μM) C13 50%(10μM) C14 46%(10μM)

[0154] As shown in Table 1, the compounds synthesized in the present invention all have inhibitory effects on 3CLpro; among them, compound C2 has the best inhibitory effect on 3CLpro, with an inhibition rate of 72% at 10 μM.

Claims

1. A compound targeting coronavirus 3CLpro having a structure as shown in general formula I or a pharmaceutically acceptable salt thereof: in, R 1 Selected from R 2 Selected from hydrogen, R 3 Selected from R 4 Selected from hydrogen.

2. The compound targeting coronavirus 3CLpro according to claim 1, characterized in that: R 1 Selected from R 2 Selected from hydrogen, R 3 Selected from R 4 Selected from hydrogen.

3. A compound targeting coronavirus 3CLpro or a pharmaceutically acceptable salt thereof, characterized in that: The compound targeting coronavirus 3CLpro is selected from the compounds with the following structure:

4. A compound targeting coronavirus 3CLpro or a pharmaceutically acceptable salt thereof having a structure as shown in the following formula:

5. Use of the compound targeting coronavirus 3CLpro or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 4 in the preparation of a 3CLpro inhibitor.

6. Use of a compound targeting coronavirus 3CLpro or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 4 in the preparation of a drug for treating related diseases caused by coronavirus infection.

7. The use according to claim 6, characterized in that: The coronavirus described is the new coronavirus, SARS, and Middle East respiratory syndrome coronavirus.

8. Use of a compound targeting coronavirus 3CLpro or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 4 in the preparation of a drug for treating novel coronavirus infection caused by SARS-Cov-2.

9. A pharmaceutical composition, characterized in that: The pharmaceutical composition comprises the compound targeting coronavirus 3CLpro according to any one of claims 1 to 4 or a pharmaceutically acceptable salt thereof as an active ingredient and a pharmaceutically acceptable excipient.

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