Carbazole metal complex and its preparation method and application in preparing medicine against novel coronavirus

Abstract

The present invention relates to a carbazole metal complex, a preparation method thereof, and an application thereof in the preparation of a drug for resisting the novel coronavirus. The carbazole metal complex is selected from one of the structures shown in Formula I, Formula II, or Formula III: 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 、R 10 、R 11 、R 12 、R 13 、R 14 Each is independently selected from -H, -OH, -COOH, -SH, -NH2, -NO2, -Cl, C1-C5 alkoxy or C1-C5 alkyl; M is selected from any one of Mn, Ru, Rh, Ir or Au; X is selected from any one or more of -F, -Cl, -Br, -OTf, -HCOO, -AcO, -BF4, acac, and CO. The various carbazole metal complexes provided by the present invention can achieve inhibition of 3CLPro at relatively low concentrations.

Description

Technical Field

[0001] The present invention belongs to the field of pharmaceutical technology, and in particular relates to a carbazole metal complex, a preparation method thereof, and an application thereof in the preparation of a drug against the novel coronavirus. Background Art

[0002] Coronaviruses (CoVs) are a large family of viruses named after the spikes on their envelope that resemble the solar corona, as seen under electron microscopy. They can infect mammals and birds, causing a wide range of diseases. SARS-CoV-2 belongs to the Coronaviridae family and is a single-stranded, positive-stranded RNA virus with an RNA sequence length of approximately 30 kb. The outer membrane of the virion is composed of four structural proteins: N protein (nucleocapsid), S protein (spike protein), E protein (envelope protein), and M protein (membrane protein). The S protein determines the host range and specificity of the virus.

[0003] To defeat the novel coronavirus, the development of highly effective antiviral drugs is crucial. The RNA polymerase of the novel coronavirus has been relatively conserved throughout evolution, and drugs that inhibit its activity could have a significant impact on the novel coronavirus, potentially treating the infection. 3CLPro is a 33.8 kDa protease with three domains (domains inI to IIT). It primarily mediates the post-translational processing of the polyprotein (RNA polymerase precursor), releasing key viral replicative enzymes such as RdRp and helicase. It participates in the assembly of the transcription-translation machinery and plays a key role in viral replication. Humans lack a homologous protease, and because its cleavage specificity differs from that of human proteases, it is considered an excellent target for the development of antiviral drugs against the novel coronavirus. Therefore, 3CLPro inhibitors are currently the preferred antiviral drugs against the novel coronavirus.

[0004] However, current 3CLPro inhibitors against COVID-19, including Lerulin (Nerutvir tablets), Paxlovid, and Senoxin, have some anti-COVID-19 activity, but their types are relatively limited. Metal complexes, due to their diverse ligand structures, anion regulation, and stereochemical configurations, can produce a wide variety of structural changes. Their ability to interact with proteins makes them a potential versatile 3CLPro inhibitor, potentially also effective against COVID-19. In 2021, Bahri Ülküseven et al. reported that Schiff base metal complexes containing Fe and Ni exhibited preliminary 3CLPro inhibitory activity. At 100 µM, the average inhibition rate of the metal complex against 3CLPro was approximately 30.62 ± 3.809% (Journal of Molecular Structure 1246 (2021) 131166). In 2022, Seth M. Cohen et al. reported that pyridine carboxylic acid metal complexes containing metal Re can inhibit SARS-CoV-2 protein (Chem. Sci., 2023, 14,711-720), with the best IC 50 was 1.8 ± 0.3 µM.

[0005] However, current anti-COVID-19 drugs targeting 3CLPro have a single structure, their pharmacological activity needs to be improved, and they also have certain inhibitory activity against other cells. Therefore, it is of great significance to develop other 3CLPro inhibitors that can effectively inhibit 3CLPro expression while having lower toxicity against other cells. Summary of the Invention

[0006] In view of the fact that the types of anti-new coronavirus drugs that inhibit 3CLPro in the existing technology are relatively single and the pharmacological activity needs to be improved, the present invention provides a carbazole metal complex, a preparation method thereof, and an application in the preparation of anti-new coronavirus drugs.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention first provides a carbazole metal complex selected from one of the structures represented by Formula I, Formula II or Formula III:

[0009]

[0010] In Formula I, Formula II and Formula III, the R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R8 、R 9 、R 10 、R 11 、R 12 、R 13 、R 14 Each is independently selected from -H, -OH, -COOH, -SH, -NH2, -NO2, -Cl, C1-C5 alkoxy or C1-C5 alkyl; further preferably -H, -OH, -COOH, -SH, -NH2, -NO2, -Cl, -OCH3, -OCH2CH3, -CH3, -CH2CH3, -CH2CH2CH3, -iPr or -tBu;

[0011] In Formula I, Formula II, and Formula III, M is selected from any one of Mn, Ru, Rh, Ir, and Au;

[0012] In Formula I, Formula II, and Formula III, X is selected from any one or more of -F, -Cl, -Br, -OTf, -HCOO, -AcO, -BF4, acac, and CO.

[0013] In one embodiment of the present invention, the carbazole metal complex is selected from one of the following structures:

[0014] 、 、 、 、 、 、 、 、 、 、 .

[0015] The present invention further provides a method for preparing the carbazole metal complex:

[0016] reacting the metal salt with triethylamine and a carbazole ligand in a solvent to obtain the carbazole metal complex;

[0017] In one embodiment of the present invention, the metal salt is a metal salt of Mn, Ru, Rh, Ir or Au, selected from one or more of the anhydrous form or crystalline water form of Mn(CO)5Br, MnBr2, Mn(OTf)2, Mn(OAc)2, RhCl3, RuCl3, IrCl3, AuBr3 metal salts.

[0018] In one embodiment of the present invention, the carbazole ligand is an NNN-type carbazole ligand selected from one of the following structures:

[0019]

[0020] The R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 、R 10 、R 11 、R 12 、R 13 、R 14 Each is independently selected from -H, -OH, -COOH, -SH, -NH2, -NO2, -Cl, C1-C5 alkoxy or C1-C5 alkyl; further preferably -H, -OH, -COOH, -SH, -NH2, -NO2, -Cl, -OCH3, -OCH2CH3, -CH3, -CH2CH3, -CH2CH2CH3, -iPr or -tBu.

[0021] In one embodiment of the present invention, the molar ratio of the carbazole ligand to the metal salt is (0.5-2.0):1, which can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.5:1, 2:1, etc., and the molar ratio of triethylamine to the metal salt is (0.5-2.0):1, which can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 1:1, 1.2:1, 1.5:1, etc.

[0022] In one embodiment of the present invention, the reaction temperature is 0-100°C, preferably 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, etc., more preferably 25-80°C.

[0023] In one embodiment of the present invention, the reaction time is 10 min-24 h, which can be 1 h, 3 h, 5 h, 7 h, 9 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, etc., and more preferably 2-10 h.

[0024] In one embodiment of the present invention, the solvent is selected from an organic solvent and / or water;

[0025] In one embodiment of the present invention, the organic solvent is selected from one or a combination of acetonitrile, methanol, ethanol, dichloromethane, tetrahydrofuran, dioxane, etc.

[0026] In one embodiment of the present invention, after the reaction, there is a post-treatment step, and the post-treatment is selected from the separation and purification of the product.

[0027] In one embodiment of the present invention, the method for preparing the carbazole ligand comprises the following steps:

[0028] Under the protection of an inert gas (such as nitrogen), a reaction is carried out in a solvent with different substituted carbazoles and N-bromosuccinimide catalyzed by iron trifluoromethanesulfonate. After the reaction, the solvent is removed by spin drying and purified by column chromatography to obtain a 1,8-dibromocarbazole intermediate.

[0029] Then, 1,8-dibromocarbazole intermediate, 2-bromopyridine and 2-boronic acid pyridine were used as reaction substrates, and tetrakis(triphenylphosphine)palladium (0) was used as catalyst. The reaction was refluxed overnight in a toluene solution. After adding water, the solvent was dried and the carbazole ligand was obtained by column chromatography using a DCM:MeOH system.

[0030] The reaction temperature is preferably 80° C. The reaction time is preferably 12 h. The solvent is preferably toluene.

[0031] The present invention further provides the use of the carbazole metal complex in the preparation of drugs against the new coronavirus.

[0032] Furthermore, the present invention provides the use of carbazole metal complexes in the preparation of 3CLPro inhibitors and anti-new coronavirus drugs.

[0033] The various carbazole metal complexes provided by the present invention can inhibit 3CLPro at relatively low concentrations.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) The structural types of the carbazole metal complexes provided by the present invention are very different from the commonly used COVID-19 drugs currently on the market, enriching the structural types of anti-COVID-19 drugs; in the process of screening metal complexes as anti-COVID-19 drugs, the present application systematically investigated the inhibitory activity of different metal centers, ligand structures, anions, etc. on 3CLPro, and obtained the structure-activity relationship between this type of metal complex and the inhibitory activity, and screened out suitable carbazole metal complexes.

[0036] (2) The carbazole metal complex prepared by the present invention can achieve efficient inhibition of 3CLPro at a relatively low concentration (2.5-49.7 μM), and has low toxicity to normal cells and low inhibitory activity (greater than 62.5 μM). The inhibitory selectivity for normal cells is greater than 25 times, which greatly increases the selective inhibition of the complex against the new coronavirus, reduces the toxic side effects of antiviral drugs on patients, and increases the effect of practical clinical applications.

[0037] (3) The ligand synthesis and complex preparation of the present invention can be carried out continuously in the same reactor, that is, the continuous reaction of ligand synthesis and complex preparation can be carried out simultaneously, which can realize the synthesis and screening process of more types and quantities of complexes at the same time, making it easier to construct a compound library of 3CLPro inhibitors and realize the provision of a method for candidate metal drugs with anti-new coronavirus activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the H NMR spectrum of intermediate M-1;

[0039] Figure 2 is the H NMR spectrum of carbazole ligand L-1;

[0040] Figure 3 is the C NMR spectrum of carbazole ligand L-1;

[0041] Figure 4 This is the H NMR spectrum of the metal complex 1 of pyridinecarbazole;

[0042] Figure 5 This is the C NMR spectrum of the metal complex 4 of pyridinecarbazole;

[0043] Figure 6 This is the H NMR spectrum of the metal complex 9 of benzothiophenecarbazole;

[0044] Figure 7 This is the C NMR spectrum of the metal complex 9 of benzothiophenecarbazole;

[0045] Figure 8 This is the H NMR spectrum of the metal complex 10 of biquinolinecarbazole;

[0046] Figure 9 This is the C NMR spectrum of the metal complex 10 of biquinolinecarbazole;

[0047] Figure 10 This is the H NMR spectrum of intermediate M-2;

[0048] Figure 11 This is the C NMR spectrum of intermediate M-2;

[0049] Figure 12 is the H NMR spectrum of carbazole ligand L-6;

[0050] Figure 13 is the C NMR spectrum of carbazole ligand L-6;

[0051] Figure 14 This is the H NMR spectrum of the metal complex 11 of tert-butylpyridinecarbazole. DETAILED DESCRIPTION

[0052] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] The technical solutions of the present invention are further described below with reference to specific examples. However, the examples are intended to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or in the product instructions shall be followed. Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used, unless otherwise specified, are conventional biochemical reagents. The experimental methods described, unless otherwise specified, are conventional methods.

[0054] Example 1

[0055] A carbazole metal complex 1, the specific preparation route and structure are as follows:

[0056]

[0057] The preparation method is as follows:

[0058] (1) Preparation of carbazole ligand: Under nitrogen protection, carbazole and N-bromosuccinimide were catalyzed by iron trifluoromethanesulfonate and heated at 80 °C in toluene as solvent for overnight reaction. The solvent was then removed by spin drying and purified by column chromatography to obtain 1,8-dibromocarbazole intermediate M-1. Next, M-1 and 2-bromopyridine were used as reaction substrates and tetrakis(triphenylphosphine)palladium(0) was used as catalyst. The reaction was refluxed in toluene solution overnight, the solvent was dried by spin drying, and white solid L-1 was obtained by column chromatography using a DCM:MeOH system.

[0059] (2) Preparation of carbazole metal complex: 160.6 mg (0.5 mmol) of ligand L-1 was dispersed in 8 mL of dichloromethane under nitrogen protection, and 50.6 mg (0.5 mmol) of triethylamine, Mn(CO)5Br 68.7 mg (0.25 mmol) of the product was stirred in a constant temperature oil bath at 20°C for 12 h. After the reaction, the solvent was dried by spin-drying and washed three times with dichloromethane and methanol respectively, and then dried in vacuum to obtain 196.1 mg of a yellow solid.

[0060] The NMR data of intermediate M-1 are: 1 H NMR (400 MHz, CDCl3): δ=8.33 (s, 1H), 7.98-7.97(d, J = 4 Hz, 2H), 7.61-7.59 (d, J = 8 Hz, 2H), 7.17-7.13 (t, J= 4 Hz, 2H), such as Figure 1 As shown; 13 C NMR (100 MHz, CDCl3) δ 153.37, 150.57, 148.19, 134.18, 121.17, 120.11.

[0061] The NMR data of ligand L-1 are: 1 H NMR (400 MHz, CDCl3): δ= 13.36 (s, 1H),8.93-8.92 (m, 2H), 8.20-8.21 (m, 2H), 8.05-7.98 (m, 4H), 7.36-7.32 (m, 3H), 7.29-7.26 (m, 3H), such as Figure 2 As shown; 13 C NMR (100 MHz, CDCl3) δ 157.70, 148.96, 138.45, 136.65, 124.26, 123.43, 121.56, 121.36,120.90, 120.28, 118.83, as Figure 3 shown.

[0062] The NMR data of carbazole metal complex 1 are: 1 H NMR (400 MHz, CDCl3): δ= 8.96-8.90 (m,2H), 8.21-8.19 (m, 2H), 8.03-7.95 (m, 4H), 7.82-7.78 (m, 2H), 7.34-7.24 (m,4H), such as Figure 4 As shown; 13 C NMR (100 MHz, CDCl3) δ 170.39, 159.82, 150.03, 129.16, 128.42, 126.82, 124.43, 124.37, 123.65, 122.97, 120.93, 120.22.

[0063] Example 2

[0064] A carbazole metal complex 2, the specific preparation route and structure are as follows:

[0065]

[0066] The preparation method is as follows:

[0067] (1) Using ligand L-1 prepared in Example 1;

[0068] (2) 160.6 mg (0.5 mmol) of ligand L-1 was dispersed in 8 mL of tetrahydrofuran under nitrogen protection. 50.6 mg (0.5 mmol) of triethylamine and 104.6 mg (0.5 mmol) of RhCl3 were added, and the mixture was stirred in a 50 °C oil bath for 5 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried in a vacuum oven to obtain 2189.2 mg of a dark reddish-brown solid.

[0069] The NMR data of carbazole metal complex 2 are: 1 H NMR (400 MHz, CDCl3): δ= 8.57 (s, 2H),8.53-8.41 (m, 2H), 8.31-7.95 (m, 4H),7.75-7.34 (m, 4H), 7.21-7.16 (m, 2H). 13 CNMR (100 MHz, CDCl3) δ 158.54, 151.42, 126.33, 125.25, 125.01, 124.11,123.14, 122.58, 120.35, 120.04, 119.27.

[0070] Example 3

[0071] A carbazole metal complex 3, the specific preparation route and structure are as follows:

[0072]

[0073] The preparation method is as follows:

[0074] (1) Carbazole ligand L-1 prepared in Example 1;

[0075] (2) 160.6 mg (0.5 mmol) of ligand L-1 was dispersed in 8 mL of acetonitrile under nitrogen protection. 34.6 mg (0.25 mmol) of K2CO3 and 103.8 mg (0.5 mmol) of RuCl3 were added, and the mixture was stirred in a constant temperature oil bath at 25 °C for 10 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried under vacuum to obtain 3150.0 mg of a yellow-brown solid.

[0076] The NMR data of carbazole metal complex 3 are: 1H NMR (400 MHz, CDCl3): δ= 8.57-8.55 (m,2H), 8.49-8.37 (m, 2H), 8.32-7.93 (m, 3H), 7.69-7.23 (m, 3H), 7.19-7.15 (m,4H). 13 C NMR (100 MHz, CDCl3) δ 160.13, 155.12, 136.25, 127.54, 126.67, 123.59, 123.03, 122.18, 120.29, 120.02, 119.96.

[0077] Example 4

[0078] A carbazole metal complex 4, the specific preparation route and structure are as follows:

[0079]

[0080] The preparation method is as follows:

[0081] (1) Using ligand L-1 prepared in Example 1;

[0082] (2) 160.6 mg (0.5 mmol) of ligand L-1 was dispersed in 8 mL of toluene under nitrogen protection. 50.6 mg (0.5 mmol) of triethylamine and 179.2 mg (0.6 mmol) of IrCl3 were added, and the mixture was stirred in a 60 °C oil bath for 3 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried in a vacuum oven to obtain 4233.1 mg of a light yellow solid.

[0083] The NMR data of carbazole metal complex 4 are: 1 H NMR (400 MHz, CDCl3): δ= 9.03 (m, 2H), 8.84-8.75 (m, 2H), 8.66-8.51 (m, 3H), 8.23-7.98 (m, 3H), 7.57-7.38 (m, 4H). 13 CNMR (100 MHz, CDCl3) δ 157.81, 149.45, 139.83, 135.31, 124.36, 123.53,121.66, 121.48, 121.01, 120.38, 118.93, e.g. Figure 5 shown.

[0084] Example 5

[0085] A carbazole metal complex 5, the specific preparation route and structure are as follows:

[0086]

[0087] The preparation method is as follows:

[0088] (1) Using ligand L-1 prepared in Example 1;

[0089] (2) 160.6 mg (0.5 mmol) of ligand L-1 was dispersed in 8 mL of dichloromethane under nitrogen protection. 50.6 mg (0.5 mmol) of triethylamine and 212.3 mg (0.7 mmol) of AuCl3 were added, and the mixture was stirred in a 40 °C oil bath for 10 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried under vacuum to obtain 5282.5 mg of a dark reddish-brown solid with a yield of 96.1%.

[0090] The NMR data of carbazole metal complex 5 are: 1 H NMR (400 MHz, CDCl3): δ= 9.01(m, 2H),8.77-8.62 (m, 2H), 8.60-8.35 (m, 4H), 8.30-7.74 (m, 4H), 7.22-7.15 (m, 2H). 13 CNMR (100 MHz, CDCl3...) δ 160.13, 150.29, 138.64, 134.31, 129.55, 127.32,121.06, 120.76, 120.27, 119.77 117.38.

[0091] Example 6

[0092] A carbazole metal complex 6, the specific preparation route and structure are as follows:

[0093]

[0094] The preparation method is as follows:

[0095] (1) Using ligand L-1 prepared in Example 1;

[0096] (2) 160.6 mg (0.5 mmol) of ligand L-1 was dispersed in 8 mL of methanol solution under nitrogen protection. 50.6 mg (0.5 mmol) of triethylamine and 436.7 mg (1.0 mmol) of AuBr3 were added, and the mixture was stirred in a 40 °C oil bath for 10 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively. The mixture was then dried under vacuum to obtain 6309.4 mg of a reddish-brown solid with a yield of 91.4%.

[0097] The NMR data of carbazole metal complex 6 are: 1 H NMR (400 MHz, CDCl3): δ= 8.84 (m, 2H), 8.65-8.49 (m, 2H), 8.39-8.25 (m, 3H), 8.20-7.74 (m, 3H), 7.45-7.10 (m, 4H). 13 CNMR (100 MHz, CDCl3) δ 158.54, 152.37, 139.25, 133.17, 129.04, 128.11,122.39, 121.59, 121.22, 119.35, 118.18.

[0098] Example 7

[0099] A carbazole metal complex 7, the specific preparation route and structure are as follows:

[0100]

[0101] The preparation method is as follows:

[0102] (1) Preparation of carbazole ligand: 1,8-dibromocarbazole intermediate M-1 and 2-bromothiazole were used as reaction substrates, and tetrakis(triphenylphosphine)palladium (0) was used as catalyst. The mixture was refluxed overnight in a toluene solution. After adding water, the solvent was dried and column chromatography with a DCM:MeOH system was used to obtain a yellow solid L-2.

[0103] (2) 166.5 mg (0.5 mmol) of ligand L-2 was dispersed in 8 mL of methanol solution under nitrogen protection. 60.7 mg (0.6 mmol) of triethylamine and 103.8 mg (0.5 mmol) of RuCl3 were added, and the mixture was stirred in a constant temperature oil bath at 40 °C for 10 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol respectively. The mixture was dried under vacuum to obtain 7238.4 mg of a dark brown solid product with a yield of 88.2%.

[0104] The NMR data of carbazole ligand L-2 are: 1H NMR (400 MHz, CDCl3): δ= 12.32(s, 1H),8.82-8.49 (m, 2H), 8.27-7.75 (m, 3H), 7.69-7.55 (m, 3H), 7.52-7.29 (m, 2H). 13 CNMR (100 MHz, CDCl3) δ 151.22, 147.35, 146.12, 138.98, 137.36, 133.57,124.22, 121.36, 120.89.

[0105] The NMR data of carbazole metal complex 7 are: 1 H NMR (400 MHz, CDCl3): δ=8.90-8.57 (m,3H), 8.53-7.84 (m, 3H), 8.53-7.84 (m, 2H), 7.42-7.27 (m, 2H). 13 C NMR (100 MHz, CDCl3) δ 156.88, 153.12, 150.76, 148.45, 134.53, 133.24, 128.46, 123.65, 122.97.

[0106] Example 8

[0107] A carbazole metal complex 8, the specific preparation route and structure are as follows:

[0108]

[0109] The preparation method is as follows:

[0110] (1) Preparation of carbazole ligand: 1,8-dibromocarbazole intermediate M-1 and 2-bromo-4-methylthiazole were used as reaction substrates, and tetrakis(triphenylphosphine)palladium (0) was used as catalyst. The mixture was refluxed overnight in a toluene solution. After adding water, the solvent was dried and column chromatography with a DCM:MeOH system was used to obtain a yellow solid L-3.

[0111] (2) 180.5 mg (0.5 mmol) of ligand L-3 was dispersed in a mixture of 4 mL of methanol and 4 mL of dichloromethane under nitrogen protection. 70.8 mg (0.7 mmol) of triethylamine and 104.6 mg (0.5 mmol) of RhCl3 were added, and the mixture was stirred in a 40 °C oil bath for 10 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried under vacuum to obtain 8252.6 mg of a dark reddish-brown solid with a yield of 88.6%.

[0112] The NMR data of carbazole ligand L-3 are: 1 H NMR (400 MHz, CDCl3): δ= 12.03 (s, 1H), 8.76-8.47 (m, 4H), 8.29-7.82 (m, 2H), 7.69-7.35 (m, 2H), 2.98-2.65 (m, 6H). 13 CNMR (100 MHz, CDCl3) δ 152.11, 148.49, 148.38, 135.67, 135.02, 131.95, 122.04, 121.47, 117.45, 27.41.

[0113] The NMR data of carbazole metal complex 8 are: 1 H NMR (400 MHz, CDCl3): δ= 8.58-8.33 (m,2H), 8.30-7.91 (m, 2H), 7.58-7.32 (m, 2H), 7.31-7.27 (m, 2H), 2.74-2.51 (m,6H). 13 C NMR (100 MHz, CDCl3) δ 155.12, 149.29, 145.24, 139.64, 134.87, 130.35, 126.52, 120.93, 118.23, 29.46.

[0114] Example 9

[0115] A carbazole metal complex 9, the specific preparation route and structure are as follows:

[0116]

[0117] The preparation method is as follows:

[0118] (1) Preparation of carbazole ligand: 1,8-dibromocarbazole intermediate M-1 and 2-chloro-benzothiazole were used as reaction substrates, and tetrakis(triphenylphosphine)palladium (0) was used as catalyst. The mixture was refluxed overnight in a toluene solution. After adding water, the solvent was dried and column chromatography with a DCM:MeOH system was used to obtain a yellow solid L-4.

[0119] (2) 216.8 mg (0.5 mmol) of ligand L-4 was dispersed in a mixture of 4 mL of methanol and 4 mL of dichloromethane under nitrogen protection. 70.8 mg (0.7 mmol) of triethylamine and 103.7 mg (0.5 mmol) of RuCl3 were added, and the mixture was stirred in a 40 °C oil bath for 10 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively. The mixture was then dried under vacuum to obtain 9252.6 mg of a dark reddish-brown solid with a yield of 78.8%.

[0120] The NMR data of carbazole ligand L-4 are: 1 H NMR (400 MHz, CDCl3): δ= 11.92(s, 1H), 8.14-8.10 (m, 2H), 7.88-7.54 (m, 4H), 7.50-7.48 (m, 4H), 7.42-7.36 (m, 2H), 7.32-7.24 (m, 2H). 13 C NMR (100 MHz, CDCl3) δ 146.45, 145.83, 141.93, 140.64,137.95, 136.48, 133.29, 132.57, 130.14, 129.37, 127.82, 125.54, 119.77.

[0121] The NMR data of carbazole metal complex 9 are: 1 H NMR (400 MHz, CDCl3): δ= 8.12-8.11 (m,2H), 7.93-7.65 (m, 4H), 7.52-7.35 (m, 8H), such as Figure 6 shown. 13 C NMR (100 MHz, CDCl3) δ143.85, 140.86, 134.10, 133.55, 131.59, 130.71, 128.41, 127.65, 126.22,124.43, 117.65, 116.26, 115.79, e.g. Figure 7 shown.

[0122] Example 10

[0123] A carbazole metal complex 10, the specific preparation route and structure are as follows:

[0124]

[0125] The preparation method is as follows:

[0126] (1) Preparation of carbazole ligand: 1,8-dibromocarbazole intermediate M-1 and 1-bromoisoquinoline were used as reaction substrates, and tetrakis(triphenylphosphine)palladium (0) was used as a catalyst. The mixture was refluxed in a toluene solution overnight. After adding water, the solvent was dried and column chromatography with a DCM:MeOH system was used to obtain a white solid L-5.

[0127] (2) 210.6 mg (0.5 mmol) of ligand L-5 was dispersed in 8 mL of water under nitrogen protection. 101.2 mg (1.0 mmol) of triethylamine and 212.3 mg (0.7 mmol) of AuCl3 were added, and the mixture was stirred in a 170 °C oil bath for 12 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried under vacuum to obtain 10253.8 mg of a brown solid.

[0128] The NMR data of carbazole ligand L-5 are: 1 H NMR (400 MHz, CDCl3): δ=11.15 (s, 1H),8.97-8.93 (m, 2H), 8.45-8.42 (m, 2H), 8.30-8.22 (m, 4H), 7.88-7.84 (m, 2H),7.80-7.76 (m, 2H),7.72-7.67 (m, 2H), 7.50-7.47 (m, 2H), 7.41-7.38 (m, 2H). 13 CNMR (100 MHz, CDCl3) δ 165.82, 154.66, 153.25, 146.35, 142.39, 135.71,134.67, 133.84, 133.05, 132.93, 129.15, 128.45, 126.13, 119.28, 117.14.

[0129] The NMR data of carbazole metal complex 10 are: 1 H NMR (400 MHz, CDCl3): δ= 8.85-8.82 (m,2H), 8.39-8.36 (m, 2H), 8.20-8.14 (m, 4H), 7.94-7.92 (m, 2H), 7.79-7.75 (m,2H),7.62-7.57 (m, 2H), 7.48-7.45 (m, 2H), 7.39-7.36 (m, 2H), such as Figure 8 shown. 13C NMR (100 MHz, CDCl3) δ 160.71, 152.50, 152.13, 143.88, 141.65, 134.56, 133.57,133.17, 132.62, 131.97, 128.41, 127.71, 124.05, 117.74, 116.23, as Figure 9 shown.

[0130] Example 11

[0131] A carbazole metal complex 11, the specific preparation route and structure are as follows:

[0132]

[0133] The preparation method is as follows:

[0134] (1) Preparation of carbazole ligand: Under nitrogen protection, 3,6-di-tert-butylcarbazole and N-bromosuccinimide were catalyzed by iron trifluoromethanesulfonate and used as solvent. o The reaction was heated at 400 °C overnight, after which the solvent was removed by spin drying and purified by column chromatography to obtain the 1,8-dibromocarbazole intermediate M-2. Next, 1,8-dibromo-3,6-di-tert-butylcarbazole and 2-bromopyridine were used as reaction substrates, and tetrakis(triphenylphosphine)palladium(0) was used as a catalyst. The reaction was refluxed in a toluene solution overnight, and after adding water, the solvent was dried by spin drying. The reaction was purified by column chromatography using a DCM:MeOH system to obtain a white solid L-6.

[0135] (2) 216.6 mg (0.5 mmol) of ligand L-6 was dispersed in 8 mL of methanol under nitrogen protection. 80.9 mg (0.8 mmol) of triethylamine and 151.6 mg (0.5 mmol) of AuCl3 were added, and the mixture was stirred in a 40 °C oil bath for 12 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively. The mixture was then dried under vacuum to obtain 11331.2 mg of a light yellow solid product.

[0136] The NMR data of carbazole intermediate M-2 are: 1 H NMR (400 MHz, CDCl3): δ= 8.13 (s, 1H),7.97-7.96(d, J = 4 Hz, 2H), 7.64-7.63(d, J = 4 Hz, 2H), 1.43(s, 18H), e.g. Figure 10 shown. 13C NMR (100 MHz, CDCl3) δ 144.77, 136.31, 126.66, 124.81, 115.99, 104.02,34.96,31.95, as Figure 11 shown.

[0137] The NMR data of carbazole ligand L-6 are: 1 H NMR (400 MHz, CDCl3): δ= 12.87 (s, 1H),8.90-8.89 (m, 2H), 8.24-8.23 (m, 2H), 8.05-8.02 (m, 4H), 7.84-7.80 (m, 2H),7.26-7.23 (m, 2H), 1.43(s, 18H), such as Figure 12 shown. 13 C NMR (100 MHz, CDCl3) δ 158.18,149.04, 141.44, 137.10, 136.50, 124.17, 121.17, 121.15, 120.23, 117.84,34.89, 32.22, as Figure 13 shown.

[0138] The NMR data of carbazole metal complex 11 are: 1 H NMR (400 MHz, CDCl3): δ= 8.83-8.81 (m,2H), 8.15 (s, 2H), 7.98-7.94 (m, 4H), 7.77-7.73 (m, 2H), 7.19-7.16 (m, 2H),1.47(s, 18H), such as Figure 14 shown. 13 C NMR (100 MHz, CDCl3) δ 160.23, 150.15, 143.37, 138.20, 135.16, 126.78, 120.37, 120.77, 120.03, 118.36, 34.47, 32.10.

[0139] Example 12

[0140] A carbazole metal complex 3, the specific preparation route and structure are as follows:

[0141]

[0142] The preparation method is as follows:

[0143] (1) Preparation of pyridine-containing carbazole ligand: 1,8-dibromocarbazole intermediate M-1 was used as the reaction substrate, 2-(tributyltin)pyridine was added, and tetrakis(triphenylphosphine)palladium (0) was used as the catalyst. The reaction was refluxed in a toluene solution overnight. After adding water, the reaction solvent was dried and column chromatography was performed using a DCM:MeOH system to obtain a white solid L-1.

[0144] (2) Preparation of carbazole metal complex: The method for preparing 3 in Example 1 was used.

[0145] Example 13

[0146] A carbazole metal complex 3, the specific preparation route and structure are as follows:

[0147]

[0148] The preparation method is as follows:

[0149] (1) Preparation of pyridine-containing carbazole ligand: 1,8-dibromocarbazole intermediate M-1 was used as the reaction substrate, 2-pyridine borate was added, and tetrakis(triphenylphosphine)palladium (0) was used as the catalyst. The reaction was refluxed in a toluene solution overnight. After adding water, the reaction solvent was dried and column chromatography was performed using a DCM:MeOH system to obtain a white solid L-1.

[0150] (2) Preparation of carbazole metal complex: The method for preparing 3 in Example 1 was used.

[0151] Example 14

[0152] The only difference from Example 1 is that in this preparation example, mesitylene is used as solvent instead of toluene in the preparation of L-1, and 90.5 mg of a yellow solid 3 is obtained.

[0153] Example 15

[0154] A carbazole complex 3, the specific preparation route and structure are as follows:

[0155]

[0156] The preparation method is as follows:

[0157] The metal complex was prepared directly by a one-pot three-step method: under nitrogen protection, 0.5 mmol of carbazole and N-bromosuccinimide were added and catalyzed by iron trifluoromethanesulfonate. When toluene was used as solvent, 80 oThe reaction was heated at 40°C overnight. 0.5 mmol of 2-pyridineboronic acid and tetrakis(triphenylphosphine)palladium (0) were added and the mixture was refluxed in toluene overnight. 0.5 mmol of triethylamine and 0.5 mmol of IrCl₃ were added and the mixture was stirred in a 40°C oil bath for 12 h. After the reaction, the solvent was dried and washed three times with dichloromethane and methanol, respectively, and then dried under vacuum to obtain a yellow solid 3.

[0158] From the above preparation examples and structural characterizations of different carbazole complexes, it can be seen that the present invention successfully prepared a variety of carbazole metal complexes with different structures. The metal complexes of the present invention have a wide reaction temperature range for the preparation process, a large number of optional solvents, and relatively simple reaction steps and post-treatment methods.

[0159] At the same time, the ligand synthesis and complex preparation of the present invention can be continuously reacted in the same reactor. Therefore, the present invention can simultaneously carry out multi-component continuous reactions of ligand synthesis and corresponding complex preparation, and can simultaneously carry out more types and quantities of complex synthesis and screening processes, making it easier to construct a compound library of 3CLPro inhibitors, and provide a method for screening candidate metal drugs with anti-new crown activity.

[0160] Detection of biological activity

[0161] The method for determining the inhibitory activity of different carbazole metal complexes against 3CLPro is as follows:

[0162] The carbazole metal complexes of different structures to be tested were prepared into a series of gradient concentration solutions, including 0.125 μM, 0.25 μM, 0.5 μM, 1.0 μM, 2.0 μM, 4.0 μM, 8.0 μM, 16.0 μM, 32.0 μM, and 100 μM. 3CLPro protease and FRET substrate were mixed in proportion, and different concentrations of the test compounds were added. The fluorescence signal changes were measured by microplate reader, and the inhibition rate and inhibition concentration of different carbazole metal complexes were calculated to preliminarily evaluate the inhibitory effect of different carbazole metal complexes on 3CLPro protease activity. See Table 1 for details.

[0163] Table 1 The half-inhibitory activity of each metal complex against 3CLPro in the examples, i.e. IC 50 Value (μM)

[0164] Carbazole metal complexes <![CDATA[IC 50 ]]> Carbazole metal complexes <![CDATA[IC 50 ]]> 1 49.7 7 6.8 2 21.3 8 29.5 3 2.5 9 26.3 4 9.4 10 19.7 5 18.5 11 18.8 6 24.3

[0165] From the examples and test results, it can be seen that when the carbazole complexes of different metals provided by the present invention are used as 3CLPro inhibitors to achieve basic research on the inhibition of new coronaviruses, most of the complexes have relatively high inhibitory activity against 3CLPro, among which carbazole metal complex 3 has the highest inhibitory activity against 3CLPro, IC50 is 2.5 μM.

[0166] It can be seen from the examples and test results that when the different carbazole metal complexes prepared from the carbazole ligands provided by the present invention are used as basic research on 3CLPro inhibitors, most of the carbazole metal complexes have good inhibitory activity against 3CLPro protease. When complexes 3 and 7 are compared, the carbazole complexes containing pyridine substituents have relatively higher inhibitory activity against 3CLPro.

[0167] It can be seen from the examples and test results that when the carbazole metal complexes prepared from the carbazole ligands provided by the present invention are used as basic research on 3CLPro inhibitors, most of the carbazole metal complexes have good inhibitory activity against 3CLPro protease. When complexes 1, 2, 3, 4, and 5 are compared, the carbazole complexes containing metal ruthenium have relatively high inhibitory activity against 3CLPro.

[0168] It can be seen from the examples and test results that when the carbazole metal complexes prepared from the carbazole ligands provided by the present invention are used as basic research on 3CLPro inhibitors, most of the carbazole metal complexes have good inhibitory activity against 3CLPro protease. When complexes 5 and 6 are compared, the chloride-containing carbazole complex has relatively higher inhibitory activity against 3CLPro.

[0169] It can be seen from the examples and test results that in the present invention, as the ligand structure, counter anion, and metal center corresponding to the carbazole metal complex are different, the different metal complexes prepared have different inhibitory activities against 3CLPro.

[0170] In addition, the inhibitory activity of carbazole metal complex 3 on EBAS-2B in normal cells was further tested using carbazole metal complex 3 as an object.

[0171] The method for determining the inhibitory activity of carbazole metal complex 3 on normal cell EBAS-2B is as follows: EBAS-2B cells in the logarithmic growth phase are inoculated into 96-well plates, and an equal volume of PBS is added to the edge of the plate to prevent edge effects. Place the plate in an incubator and take it out after culturing for 24 hours. The cells are treated with carbazole metal complex 3 at concentrations of 0.125 μM, 0.25 μM, 0.5 μM, 1.0 μM, 2.0 μM, 4.0 μM, 8.0 μM, 16.0 μM, 32.0 μM, and 100 μM and incubated for 24 hours. The control wells are incubated for 24 hours with DMSO at the same concentration as the drug. 20 μL of CCK8 reagent at a concentration of 5 mg / mL is added to each well, and the wells are replicated three times, and then incubated in the incubator for 1 hour. The absorbance at 450 nm is monitored using a microplate reader to calculate the IC value of carbazole metal complex 3. 50 .

[0172] The above test results show that the IC of carbazole metal complex 3 on normal cell EBAS-2B 50 The value is 62.5 μM.

[0173] The performance test shows that carbazole metal complex 3 can not only achieve high efficiency inhibition of 3CLPro at lower concentrations (IC 50 = 2.5 µM), and the IC 50 The inhibitory selectivity is greater than 25 times, which is 62.5 µM, has low toxicity, and is very likely to reduce the toxic side effects of antiviral drugs on patients and increase the effectiveness of clinical applications.

[0174] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A carbazole metal complex, characterized in that: Select one of the following structures: 、 、 、 、 、 、 、 、 、 、 。 2. The method for preparing the carbazole metal complex according to claim 1, wherein: reacting the metal salt with triethylamine and a carbazole ligand in a solvent to obtain the carbazole metal complex; The metal salt is selected from one or more of the anhydrous form or crystalline water form of Mn(CO)5Br, RhCl3, RuCl3, IrCl3, and AuBr3 salts; The carbazole ligand is an NNN-type carbazole ligand selected from one of the following structures: 、 、 、 、 or .

3. The method for preparing a carbazole metal complex according to claim 2, wherein: The molar ratio of the carbazole ligand to the metal salt is (0.5-2.0):1, and the molar ratio of triethylamine to the metal salt is (0.5-2.0):

1.

4. The method for preparing a carbazole metal complex according to claim 2, wherein: The reaction temperature is 0-100° C., and the reaction time is 10 min-24 h.

5. The method for preparing the carbazole metal complex according to claim 2, wherein: The solvent is selected from an organic solvent and / or water; The organic solvent is selected from one or a combination of acetonitrile, methanol, ethanol, dichloromethane, tetrahydrofuran, and dioxane.

6. Use of the carbazole metal complex according to claim 1 in the preparation of a 3CLPro inhibitor.

7. The use according to claim 6, characterized in that The 3CLPro inhibitor is used to fight the new coronavirus.

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