Naphthoquinone compound targeting novel coronavirus and medical use thereof

Abstract

This invention provides naphthoquinone compounds targeting the novel coronavirus and their pharmaceutical uses. In vitro activity assays show that the compounds disclosed in this invention can inhibit the main protease (Mpro) activity of the SARS-CoV-2 novel coronavirus. In vitro activity assays show that some compounds, at a concentration of 1 μM, exhibit an enzyme inhibition rate of over 90%, significantly superior to the positive control drug shikonin, and can effectively reduce the replication capacity of wild-type and various mutant strains of the novel coronavirus in the host. In vitro cytotoxicity assays show that the compounds disclosed in this patent have significantly lower toxicity to normal host cells (HSF cells) than the positive control drug shikonin, indicating promising application prospects as drug candidates against COVID-19 infection.

Description

Technical Field

[0001] This invention relates to the pharmaceutical field, specifically to a naphthoquinone compound targeting the novel coronavirus and its pharmaceutical uses. Background Technology

[0002] The novel coronavirus (SARS-CoV-2), a severe acute respiratory infectious disease, has led to the outbreak of pneumonia (COVID-19), seriously endangering global public health. According to the World Health Organization, as of May 25, 2025, there were over 777.95 million confirmed cases of COVID-19 and 7.09 million confirmed deaths, making it one of the deadliest pandemics in human history. Since December 2021, the number of cases appears to be rapidly increasing due to the rapid spread of the SARS-CoV-2 Omeprone variant. Therefore, there is an urgent need to develop highly effective drugs against this ongoing coronavirus disease.

[0003] The novel coronavirus is a single-stranded, positive-sense RNA virus, highly homologous to SARS coronavirus and MERS-CoV. After entering a host cell, the coronavirus releases its nucleic acid into the cytoplasm, and the ORF1a / b region of the viral genome is translated into two polyprotein precursors (pp1a and pp1ab), which are cleaved into viral structural and non-structural proteins by the main protease (Mpro). Mpro is also known as a 3C-like protease because its cleavage site specificity is similar to that of pyruvate 3C proteases. The non-structural proteins produced by Mpro are involved in the synthesis of viral subgenomic RNA and four structural proteins crucial for viral replication. Because the main protease plays a key role in the coronavirus life cycle and has no homologous proteins in the host cell, Mpro is an ideal target for antiviral drug development. Although dozens of different vaccines have been authorized to combat COVID-19, certain variants of spike protein mutations may escape the immune response after vaccination.

[0004] Natural bioactive compounds are a source of lead compounds for antiviral drug screening. Shikonin, a natural naphthoquinone isolated from *Lithospermum erythrorhizon*, exhibits significant antiviral, antibacterial, anti-inflammatory, and anticancer activities. Studies have shown that this compound has inhibitory activity against the main protease of the novel coronavirus, with an IC50 value of [missing information]. 50 The value was 15.75 ± 8.22 μM. Although shikonin has strong antiviral activity, it has not yet been used in clinical trials, mainly due to the non-specific cytotoxicity it produces in humans. At concentrations that inhibit the main viral protease, it also has a certain killing effect on normal host cells; this limitation restricts the clinical application of shikonin as an antiviral drug against the novel coronavirus.

[0005] In conclusion, a new technical solution is urgently needed to address the problems existing in the current technology. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention discloses a naphthoquinone compound targeting the novel coronavirus and its pharmaceutical uses. Pharmacological studies show that the naphthoquinone compound of this invention has strong inhibitory activity against the 2019-nCoV virus 3CL proteolytic enzyme.

[0007] One object of the present invention is to provide a naphthoquinone compound targeting the novel coronavirus, wherein the structural formula of the naphthoquinone compound targeting the novel coronavirus is shown in formula (A) or formula (B): ; in, M and M' are absent, or are independently selected from alkyl groups having 1-16 carbon atoms; R and R' are independently selected from one of hydrogen, a straight-chain alkyl group with 1-30 carbon atoms, a branched alkyl group with 1-30 carbon atoms, an aromatic hydrocarbon derivative with 6-60 carbon atoms, or a heterocyclic derivative with 1-60 carbon atoms. The aromatic hydrocarbon derivative is selected from groups containing one or more aromatic ring structures, wherein all hydrogen atoms in the aromatic ring structure are not substituted. or One or more hydrogen atoms at any position on one or more aromatic ring structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups; The heterocyclic derivative is selected from groups containing one or more heterocyclic structures, wherein all hydrogen atoms in the heterocyclic structures are unsubstituted. or One or more hydrogen atoms at any position on one or more heterocyclic structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups; R1, R2, R5, and R6 are independently selected from O and N-OH; R3, R4, R7, and R8 are independently selected from alkoxy groups.

[0008] Furthermore, R and R' are independently selected from one of the following structures: ; in, R9, R 10 R 11 R 12 R 13 R14 R 15 R 16 R 17 R 18 It is independently selected from one of H, halogen atom, nitro group, and alkoxy group.

[0009] Furthermore, the structural formula of the naphthoquinone compound targeting the novel coronavirus is shown in formula (I): ; in, M' is absent, or is selected from alkyl groups having 1-16 carbon atoms; R' is selected from one of hydrogen, straight-chain alkyl with 1-30 carbon atoms, branched alkyl with 1-30 carbon atoms, aromatic hydrocarbon derivatives with 6-60 carbon atoms, and heterocyclic derivatives with 1-60 carbon atoms; The aromatic hydrocarbon derivative is selected from groups containing one or more aromatic ring structures, wherein all hydrogen atoms in the aromatic ring structure are not substituted. or One or more hydrogen atoms at any position on one or more aromatic ring structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups; The heterocyclic derivative is selected from groups containing one or more heterocyclic structures, wherein all hydrogen atoms in the heterocyclic structures are unsubstituted. or One or more hydrogen atoms at any position on one or more heterocyclic structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups.

[0010] Another object of the present invention is to provide the use of the naphthoquinone compounds targeting the novel coronavirus in the preparation of drugs against the novel coronavirus 2019-nCoV.

[0011] The present invention has the following beneficial effects: This invention provides a naphthoquinone compound targeting the novel coronavirus and its pharmaceutical uses. In vitro activity assays show that the compound disclosed in this invention can inhibit the main protease (Mpro) activity of the novel coronavirus SARS-CoV-2. In vitro activity assays show that the compound provided in this invention, at a concentration of 1 μM, exhibits an enzyme inhibition rate of over 90%, significantly superior to the positive control drug shikonin, and can effectively reduce the replication capacity of wild-type and various mutant strains of the novel coronavirus in the host. In vitro cytotoxicity assays show that the compound provided in this invention has significantly lower toxicity to normal host cells (HSF cells) than the positive control drug shikonin, indicating its promising application as a drug candidate against COVID-19 infection. Attached Figure Description

[0012] Figure 1 A schematic diagram of the preparation of intermediate (V) and compound I-1 is shown.

[0013] Figure 2 The IC50 of the compound inhibiting SARS-CoV-2 Mpro was shown. 50 Fitting results; among which, Figure 2 (a) shows the IC50 of shikonin in inhibiting SARS-CoV-2 Mpro. 50 Fitting results; Figure 2 (b) shows the IC50 of compound I-5 in inhibiting SARS-CoV-2 Mpro. 50 Fitting results; Figure 2 (c) shows the IC50 of compound I-13 in inhibiting SARS-CoV-2 Mpro. 50 Fitting results; Figure 2 (d) shows the IC50 of compound I-25 in inhibiting SARS-CoV-2 Mpro. 50 Fitting results. Detailed Implementation

[0014] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0015] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0016] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0017] Unless otherwise specified, the experimental methods in the following preparation examples and embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0018] Preparation Example This preparation example relates to a method for preparing the key intermediate 2-(1'-hydroxy-4'-methyl-3'-pentenyl)-1,4,5,8-tetramethoxynaphthalene (V), including the following steps: ; Activated zinc powder (30 g, 0.47 mol) was placed in anhydrous THF (100 mL), and bromoisoprene (25 mL) was slowly added dropwise under N2 protection. After the addition was complete, the mixture was stirred at room temperature for 2 h. The reaction was stopped, and after standing for 10 min, the supernatant was poured off and centrifuged at 4200 rpm for 8 min to remove the zinc powder. The supernatant was the zinc bromine reagent, which was reserved for later use. 1,4,5,8-Tetramethoxynaphthalene (5 g, 18.1 mmol) was dissolved in anhydrous THF (20 mL). Under N2 protection, the prepared zinc bromine reagent was added dropwise to the reaction solution. The reaction was complete when the color of the solution changed from orange-yellow to colorless and white bubbles were generated. After the addition was complete, the mixture was stirred at room temperature for 2 h. After the reaction was complete, hexamethylphosphoric triamine (HMPA, 40 mL) was added to the reaction solution, and the temperature was gradually increased to 180 °C while THF was evaporated under reduced pressure. After the THF was completely evaporated, the mixture was stirred for 1 h. The reaction was stopped, and the hot reaction solution was poured into a saturated NH4Cl aqueous solution. The solution was extracted with ethyl acetate, the organic phase was washed with saturated NaCl, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated by column chromatography to obtain 5.2 g of intermediate (V) as a yellow oily substance with a yield of 82.9%. 1 H NMR (400 MHz, CDCl3) δ 7.96 (s, 1H),7.00 (s, 1H), 6.79 (s, 2H), 5.26-5.18 (m, 2H), 3.91 (s, 6H), 3.86 (s, 3H), 3.731 (s, 3H), 2.52-2.48 (m, 2H), 1.69 (s, 3H), 1.62 (s, 3H). Example 1 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridin-4''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-1) having structural formula (Ⅰ), comprising the following steps: Step 1: Intermediate (V) (0.5 mmol), DMAP (0.25 mmol), and pyridine-4-carboxylic acid (1 mmol) were suspended in 8.0 mL of anhydrous dichloromethane. EDCI (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride), (0.19 g, 1 mmol), was added to the reaction solvent. After the addition was complete, the mixture was stirred overnight at room temperature. After the reaction was complete, dichloromethane was added to dilute the reaction solution. The organic layer was washed with water and dried over anhydrous sodium sulfate. The solvent was then evaporated, and the mixture was separated by column chromatography to obtain a pale yellow oil.

[0019] Step 2: Dissolve the oily substance in a 10 mL solution of dichloromethane / acetonitrile (dichloromethane to acetonitrile volume ratio 3:1). Under ice bath conditions, slowly add an aqueous solution containing cerium ammonium nitrate (1 mmol). After the addition is complete, continue stirring for 10 min. After the reaction is complete, extract with ethyl acetate, wash the organic phase with saturated NaCl, dry with anhydrous sodium sulfate, concentrate under reduced pressure, and separate by column chromatography to obtain 5,8-dimethoxy-6-(1'-(pyridin-4''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (Ⅰ-1), a yellow oily liquid, yield: 78.32%. 1 H NMR (400 MHz, Chloroform-d) δ 8.83(s, 2H), 7.87 (d, J = 4.8 Hz, 2H), 7.34 - 7.22 (m, 1H), 6.79 (d, J = 2.1 Hz,2H), 6.36 (td, J = 6.0, 4.9, 2.1 Hz, 1H), 5.27 - 5.11 (m, 1H), 3.96 (d, J =2.0 Hz, 3H), 3.89 (d, J = 2.1 Hz, 3H), 2.66 (qd, J = 15.9, 14.9, 8.2 Hz, 2H), 1.68 (s, 3H), 1.57 (s, 3H). Figure 1 A schematic diagram of the preparation of intermediate (V) and compound I-1 is shown.

[0020] Example 2 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridin-3''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-2) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-2 is a yellow oily substance with a yield of 76.22%. 1 H NMR (400 MHz, Chloroform-d) δ 9.24 (s,1H), 8.78 (d, J = 4.8 Hz, 1H), 8.28 (dd, J = 8.0, 2.1 Hz, 1H), 7.40 (dd, J =8.1, 4.7 Hz, 1H), 7.26 (d, J = 1.9 Hz, 1H), 6.75 (d, J = 1.9 Hz, 2H), 6.34 (td, J = 6.0, 4.9, 2.0 Hz, 1H), 5.15 (d, J = 7.5 Hz, 1H), 3.93 (d, J = 2.0Hz, 3H), 3.85 (d, J = 2.0 Hz, 3H), 2.74 - 2.47 (m, 2H), 1.64 (s, 3H), 1.53 (s, 3H). Example 3 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridin-2''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-3) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-3 is a yellow oily substance with a yield of 79.64%. 1H NMR (400 MHz, Chloroform-d) δ 8.74 (d, J =4.8 Hz, 1H), 8.08 (d, J = 7.7 Hz, 1H), 7.83 (td, J = 7.8, 1.8 Hz, 1H), 7.50 -7.42 (m, 2H), 6.73 (s, 2H), 6.36 (dd, J = 7.6, 5.3 Hz, 1H), 5.18 (t, J = 7.4Hz, 1H), 3.93 (s, 3H), 3.86 (s, 3H), 2.67 (d, J = 7.0 Hz, 2H), 1.61 (s, 3H),1.52 (s, 3H). Example 4 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(thiophene-2''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-4) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-thiophenecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-4 is a yellow oily substance with a yield of 81.44%. 1 H NMR (400 MHz, Chloroform-d) δ 7.74 (t, J =3.8 Hz, 1H), 7.51 (t, J = 4.5 Hz, 1H), 7.27 (d, J = 4.2 Hz, 1H), 7.02 (q, J =4.0 Hz, 1H), 6.66 (t, J = 3.7 Hz, 2H), 6.20 (dt, J = 8.4, 4.3 Hz, 1H), 5.09(q, J = 6.1, 5.4 Hz, 1H), 3.85 (d, J = 3.8 Hz, 3H), 3.80 (d, J = 3.9 Hz, 3H), 2.67 - 2.42 (m, 2H), 1.56 (d, J = 3.7 Hz, 3H), 1.46 (d, J = 3.8 Hz, 3H). Example 5 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-2''-fluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-5) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-fluorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-5 is a yellow oily substance with a yield of 79.66%. 1 H NMR (400 MHz, Chloroform-d) δ 7.74 (td, J= 7.6, 1.9 Hz, 1H), 7.35 (tdd, J = 7.4, 4.8, 2.0 Hz, 1H), 7.13 - 6.86 (m,3H), 6.57 (d, J = 1.2 Hz, 2H), 6.20 (dd, J = 7.4, 4.5 Hz, 1H), 5.05 - 4.92(m, 1H), 3.74 (d, J = 11.7 Hz, 6H), 2.64 - 2.25 (m, 2H), 1.64 - 1.39 (m, 3H),1.40 - 1.17 (m, 3H). Example 6 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-3'',4'',5''-trimethoxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-6) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3,4,5-trimethoxybenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-6 is a yellow oily substance with a yield of 69.56%. 1 H NMR (600 MHz, Chloroform-d) δ7.32 (s, 2H), 7.29 (s, 1H), 6.78 (d, J = 1.0 Hz, 2H), 6.27 (dd, J = 7.7, 4.6Hz, 1H), 5.24 - 5.18 (m, 1H), 3.98 (s, 3H), 3.92 (s, 3H), 3.90 (s, 3H), 3.88(s, 6H), 2.85 - 2.47 (m, 2H), 1.69 (d, J = 1.4 Hz, 3H), 1.61 (d, J = 1.4 Hz, 3H). Example 7 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(phenyl-1''-acetoxy-4''-methoxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-7) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 4-methoxyphenylacetic acid is used instead of 4-pyridinecarboxylic acid. Compound I-7 is a yellow oily substance with a yield of 62.32%. 1 H NMR (400 MHz, Chloroform-d) δ 7.22(s, 1H), 7.21 (d, J = 1.9 Hz, 1H), 6.91 (s, 1H), 6.86 (s, 1H), 6.84 (s, 1H),6.76 (d, J = 1.7 Hz, 2H), 6.08 (dd, J = 7.8, 4.3 Hz, 1H), 5.18 - 5.03 (m,1H), 3.90 (s, 3H), 3.79 (s, 3H), 3.65 (s, 3H), 3.62 (d, J = 7.7 Hz, 2H), 2.47(ddt, J = 59.6, 15.1, 6.8 Hz, 2H), 1.67 (s, 3H), 1.52 (s, 3H). Example 8 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-2'',5''-dimethoxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-8) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2,5-dimethoxybenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-8 is a yellow oily substance with a yield of 65.92%. 1H NMR (400 MHz, Chloroform-d) δ7.59 (t, J = 3.0 Hz, 2H), 7.36 (d, J = 2.5 Hz, 1H), 7.30 (t, J = 3.0 Hz, 1H), 6.71 (d, J = 2.6 Hz, 2H), 6.23 (dt, J = 7.2, 3.3 Hz, 1H), 5.17 (d, J = 7.7Hz, 1H), 3.97 (d, J = 2.6 Hz, 12H), 2.79 - 2.41 (m, 2H), 1.62 (s, 3H), 1.46(s, 3H). Example 9 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyrazine-2''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-9) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-pyrazinic acid is used instead of 4-pyridinecarboxylic acid. Compound I-9 is a yellow oily substance with a yield of 85.92%. 1 H NMR (400 MHz, Chloroform-d) δ 9.33 (s,1H), 8.79 (d, J = 14.4 Hz, 2H), 7.43 (s, 1H), 6.80 (s, 2H), 6.56 - 6.35 (m,1H), 5.21 (t, J = 7.4 Hz, 1H), 3.98 (s, 3H), 3.92 (s, 3H), 2.72 (q, J = 7.6,6.9 Hz, 2H), 1.68 (s, 3H), 1.58 (s, 3H). Example 10 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzofuran-2''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-10) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-benzofuran carboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-10 is a yellow oily substance with a yield of 83.72%. 1H NMR (400 MHz, Chloroform-d) δ 7.64(d, J = 7.9 Hz, 1H), 7.52 (d, J = 8.0 Hz, 2H), 7.44 - 7.36 (m, 1H), 7.32 (s,1H), 7.25 (t, J = 7.5 Hz, 1H), 6.72 (s, 2H), 6.31 (dd, J = 7.6, 4.9 Hz, 1H), 5.23 - 5.00 (m, 1H), 3.91 (s, 3H), 3.86 (s, 3H), 2.62 (tq, J = 14.9, 7.5, 6.6Hz, 2H), 1.62 (s, 3H), 1.52 (s, 3H). Example 11 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(furan-2''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-11) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-furan carboxylic acid is used instead of 4-pyridine carboxylic acid. Compound I-11 is a yellow oily substance with a yield of 85.32%. 1 H NMR (400 MHz, Chloroform-d) δ 7.56 (dd, J= 1.8, 0.9 Hz, 1H), 7.28 (s, 1H), 7.25 - 7.09 (m, 1H), 6.72 (d, J = 1.0 Hz,2H), 6.49 (dd, J = 3.5, 1.7 Hz, 1H), 6.25 (dd, J = 7.6, 4.8 Hz, 1H), 5.20 -5.01 (m, 1H), 3.89 (d, J = 1.0 Hz, 3H), 3.86 (d, J = 1.0 Hz, 3H), 2.56 (tt, J= 14.8, 6.4 Hz, 2H), 1.61 (s, 3H), 1.50 (d, J = 1.4 Hz, 3H). Example 12 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzene-1''-formyloxy-2'',3''-difluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-12) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2,3-difluorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-12 is a yellow oily substance with a yield of 89.42%. 1 H NMR (400 MHz, Chloroform-d) δ 7.64(ddt, J = 7.7, 5.8, 1.7 Hz, 1H), 7.39 (d, J = 1.3 Hz, 1H), 7.37 - 7.29 (m,1H), 7.13 (dddt, J = 8.1, 6.5, 4.5, 2.1 Hz, 1H), 6.72 (d, J = 1.2 Hz, 2H), 6.37 (dd, J = 7.4, 4.6 Hz, 1H), 5.13 (td, J = 6.4, 5.8, 3.1 Hz, 1H), 3.90 (d,J = 1.3 Hz, 3H), 3.88 (d, J = 1.2 Hz, 3H), 2.57 (ddt, J = 29.9, 15.0, 8.2 Hz, 2H), 1.60 (s, 3H), 1.44 (s, 3H). Example 13 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-4''-fluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-13) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 4-fluorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-13 is a yellow oily substance with a yield of 87.66%. 1 H NMR (400 MHz, DMSO-d6) δ 8.42 - 8.00 (m,2H), 7.57 (s, 1H), 7.41 (td, J = 8.9, 2.0 Hz, 2H), 6.85 (d, J = 4.1 Hz, 2H), 6.28 (dd, J = 7.8, 5.1 Hz, 1H), 5.31 - 5.08 (m, 1H), 3.88 (s, 3H), 3.84 (s,3H), 2.70 (dp, J = 28.1, 7.7 Hz, 2H), 1.65 (s, 3H), 1.58 (d, J = 1.3 Hz, 3H). Example 14 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-3''-fluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-14) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-fluorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-14 is a yellow oily substance with a yield of 85.96%. 1 H NMR (400 MHz, Chloroform-d) δ 7.90 (dd, J= 7.6, 1.5 Hz, 1H), 7.82 (dq, J = 9.4, 1.6 Hz, 1H), 7.69 - 7.48 (m, 3H), 6.92- 6.73 (m, 2H), 6.25 (ddd, J = 7.8, 5.1, 1.6 Hz, 1H), 5.25 - 5.12 (m, 1H),3.85 (d, J = 1.6 Hz, 3H), 3.81 (d, J = 1.6 Hz, 3H), 2.67 (ddd, J = 35.6,14.8, 7.5 Hz, 2H), 1.62 (s, 3H), 1.56 (s, 3H). Example 15 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzothiophene-1''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-15) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-benzothiophene carboxylic acid is used instead of 4-pyridine carboxylic acid. Compound I-15 is a yellow oily substance with a yield of 84.26%. 1H NMR (600 MHz, Chloroform-d) δ 8.15 -8.10 (m, 1H), 7.94 - 7.84 (m, 2H), 7.53 - 7.46 (m, 1H), 7.46 - 7.42 (m, 1H),7.39 (s, 1H), 6.79 (d, J = 1.3 Hz, 2H), 6.36 (dd, J = 7.7, 4.5 Hz, 1H), 5.34- 5.14 (m, 1H), 3.98 (s, 3H), 3.92 (s, 3H), 2.67 (ddd, J = 42.9, 15.1, 8.0Hz, 2H), 1.70 (d, J = 2.0 Hz, 3H), 1.62 - 1.55 (m, 3H). Example 16 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-2-chloro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-16) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-chlorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-16 is a yellow oily substance with a yield of 82.86%. 1 H NMR (600 MHz, Chloroform-d) δ 7.83 (dd,J = 7.8, 1.6 Hz, 1H) ,δ 7.49 - 7.40 (m, 3H), 7.34 (ddd, J = 7.8, 6.8, 1.8 Hz,1H), 6.77 (d, J = 1.9 Hz, 2H), 6.37 (dd, J = 7.5, 4.6 Hz, 1H), 5.25 - 5.18(m, 1H), 3.96 (s, 3H), 3.91 (s, 3H), 2.85 - 2.45 (m, 2H), 1.67 (d, J = 1.6Hz, 3H), 1.51 (d, J = 1.5 Hz, 3H). Example 17 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-2-bromo)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-17) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-bromobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-17 is a yellow oily substance with a yield of 86.13%. 1 H NMR (400 MHz, Chloroform-d) δ 7.89 -7.83 (m, 1H), 7.78 (dd, J = 7.8, 1.4 Hz, 1H), 7.59 - 7.46 (m, 3H), 6.97 -6.71 (m, 2H), 6.25 (dd, J = 7.5, 5.3 Hz, 1H), 5.45 - 4.98 (m, 1H), 3.89 (s,3H), 3.84 (s, 3H), 2.66 (q, J = 7.2, 6.8 Hz, 2H), 1.66 (d, J = 1.5 Hz, 3H), 1.53 (d, J = 1.4 Hz, 3H). Example 18 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridine-4''-formyloxy-3-fluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-18) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-fluoro-4-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-18 is a yellow oily substance with a yield of 83.46%. 1 H NMR (400 MHz, Chloroform-d) δ 8.60(d, J = 2.3 Hz, 1H), 8.52 (d, J = 4.9 Hz, 1H), 7.72 (t, J = 5.4 Hz, 1H), 7.37(s, 1H), 6.73 (d, J = 1.4 Hz, 2H), 6.39 (dd, J = 7.4, 4.6 Hz, 1H), 5.11 (t, J= 7.5 Hz, 1H), 3.89 (d, J = 2.0 Hz, 6H), 2.58 (ddt, J = 30.0, 15.0, 8.1 Hz, 2H), 1.61 (s, 3H), 1.45 (s, 3H). Example 19 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(isoquinoline-3''-methyl-6''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-19) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-methylquinoline-6-carboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-19 is a yellow oily substance with a yield of 86.13%. 1 H NMR (400 MHz, Chloroform-d) δ 8.57(d, J = 2.0 Hz, 1H), 8.29 (dd, J = 8.8, 2.0 Hz, 1H), 8.16 (d, J = 8.5 Hz,1H), 8.08 (d, J = 8.8 Hz, 1H), 7.43 - 7.33 (m, 2H), 6.79 (s, 2H), 6.38 (dd, J= 7.6, 4.8 Hz, 1H), 5.27 (td, J = 8.2, 7.2, 4.4 Hz, 1H), 4.00 (s, 3H), 3.87(s, 3H), 2.79 (s, 3H), 2.69 (tt, J = 14.9, 6.8 Hz, 2H), 1.69 (s, 3H), 1.60(d, J = 1.4 Hz, 3H). Example 20 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(indole-1''-hydro-2''-formyloxy-5''-methoxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-20) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 1-hydro-5-methoxy-2-indolecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-20 is a yellow oil with a yield of 79.66%. 1H NMR (600 MHz, Chloroform-d)δ 8.86 (s, 1H), 7.36 (s, 1H), 7.32 (d, J = 8.9 Hz, 1H), 7.23 (dd, J = 2.2,1.0 Hz, 1H), 7.10 (d, J = 2.4 Hz, 1H), 7.02 (dd, J = 9.0, 2.5 Hz, 1H), 6.79 (d, J = 1.2 Hz, 2H), 6.34 (dd, J = 7.8, 4.5 Hz, 1H), 5.23 (ddt, J = 7.3, 5.9,1.4 Hz, 1H), 3.98 (s, 3H), 3.90 (s, 3H), 3.86 (s, 3H), 2.76 - 2.59 (m, 2H), 1.69 (d, J = 1.4 Hz, 3H), 1.60 (d, J = 1.4 Hz, 3H). Example 21 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(1'',1''-diphenyl-acetoxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-21) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2,2-diphenylacetic acid is used instead of 4-pyridinecarboxylic acid. Compound I-21 is a yellow oily substance with a yield of 76.68%. 1 H NMR (400 MHz, Chloroform-d) δ 7.27 -7.24 (m, 4H), 7.24 - 7.18 (m, 6H), 6.75 (s, 1H), 6.69 (d, J = 1.4 Hz, 2H), 6.09 (dd, J = 8.3, 4.0 Hz, 1H), 5.11 - 4.99 (m, 2H), 3.85 (s, 3H), 3.42 (s,3H), 2.62 - 2.22 (m, 2H), 1.60 (d, J = 1.5 Hz, 3H), 1.44 (d, J = 1.4 Hz, 3H). Example 22 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyrrolo-2''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-22) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 2-pyrrolecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-22 is a yellow oily substance with a yield of 78.44%. 1 H NMR (600 MHz, Chloroform-d) δ 9.29 (s,1H), 7.33 (s, 1H), 7.00 (ddq, J = 5.4, 2.7, 1.5 Hz, 2H), 6.82 - 6.69 (m, 2H),6.30 (dt, J = 3.7, 2.6 Hz, 1H), 6.26 (dd, J = 7.8, 4.5 Hz, 1H), 5.25 - 5.09(m, 1H), 3.95 (s, 3H), 3.90 (s, 3H), 2.69 - 2.48 (m, 2H), 1.68 (d, J = 1.4Hz, 3H), 1.57 (d, J = 1.4 Hz, 3H). Example 23 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzo-1''-formyloxy-3''-ethyl)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-23) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-ethylbenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-23 is a yellow oily substance with a yield of 76.46%. 1 H NMR (600 MHz, Chloroform-d) δ 7.99 (d,J = 7.9 Hz, 2H), 7.33 - 7.28 (m, 3H), 6.78 (s, 2H), 6.32 (dd, J = 7.7, 4.4Hz, 1H), 5.30 - 5.18 (m, 1H), 3.98 (s, 3H), 3.88 (s, 3H), 2.72 (q, J = 7.7Hz, 2H), 2.70 - 2.56 (m, 2H), 1.68 (s, 3H), 1.57 (s, 3H), 1.27 (t, J = 7.8Hz, 3H). Example 24 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridin-2''-formyloxy-6''-chloro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-24) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 6-chloro-2-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-24 is a yellow oily substance with a yield of 78.36%. 1 H NMR (600 MHz, Chloroform-d) δ 8.04 -7.99 (m, 1H), 7.82 (t, J = 7.8 Hz, 1H), 7.58 - 7.52 (m, 2H), 6.79 (t, J = 2.2Hz, 2H), 6.39 (dd, J = 7.7, 4.8 Hz, 1H), 5.20 (dtd, J = 7.3, 3.6, 2.9, 1.4Hz, 1H), 3.97 (d, J = 3.1 Hz, 6H), 2.70 (ddt, J = 30.1, 15.0, 8.2 Hz, 2H), 1.68 (s, 3H), 1.60 - 1.55 (m, 3H). Example 25 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-3'',5''-dichloro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-25) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3,5-dichlorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-25 is a yellow oily substance with a yield of 79.06%. 1H NMR (600 MHz, Chloroform-d) δ 7.90(d, J = 2.0 Hz, 2H), 7.59 - 7.57 (m, 1H), 7.27 (s, 1H), 6.79 (d, J = 1.5 Hz,2H), 6.32 (dd, J = 7.7, 4.9 Hz, 1H), 5.18 (qd, J = 6.9, 4.9, 2.2 Hz, 1H), 3.96 (s, 3H), 3.91 (s, 3H), 2.73 - 2.60 (m, 2H), 1.69 (d, J = 1.9 Hz, 3H), 1.60 - 1.58 (m, 3H). Example 26 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(morpholino-4''-formyloxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-26) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 6-morpholinic acid is used instead of 4-pyridinecarboxylic acid. Compound I-26 is a yellow oily substance with a yield of 77.56%. 1 H NMR (600 MHz, Chloroform-d) δ 7.25 (s,1H), 6.81 - 6.75 (m, 2H), 6.19 (dd, J = 7.8, 4.9 Hz, 1H), 5.12 - 5.08 (m,1H), 3.95 (s, 3H), 3.91 (s, 3H), 3.75 - 3.71 (m, 4H), 2.61 - 2.57 (m, 4H), 2.51 (ddd, J = 30.1, 14.9, 8.4 Hz, 2H), 1.67 (s, 3H), 1.56 - 1.52 (m, 3H). Example 27 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridine-2''-formyloxy-5''-bromo)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-27) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 5-bromo-2-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-27 is a yellow oily substance with a yield of 80.36%.1 H NMR (600 MHz, Chloroform-d) δ 8.79 -8.73 (m, 1H), 7.94 (d, J = 1.6 Hz, 2H), 7.38 (s, 1H), 6.72 (d, J = 1.4 Hz,2H), 6.33 (dd, J = 7.8, 5.1 Hz, 1H), 5.14 (tt, J = 6.9, 3.1 Hz, 1H), 3.91 (s,3H), 3.85 (s, 3H), 2.65 (qt, J = 15.0, 6.7 Hz, 2H), 1.63 - 1.59 (m, 3H), 1.53- 1.49 (m, 3H). Example 28 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridine-2''-formyloxy-3''-fluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-28) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-fluoro-2-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-28 is a yellow oily substance with a yield of 80.36%. 1 H NMR (600 MHz, Chloroform-d) δ 8.52(dd, J = 4.7, 1.6 Hz, 1H), 7.53 (ddd, J = 10.0, 8.4, 1.4 Hz, 1H), 7.49 (d, J= 3.5 Hz, 2H), 6.72 (d, J = 1.8 Hz, 2H), 6.41 (dd, J = 7.6, 4.6 Hz, 1H), 5.17- 5.11 (m, 1H), 3.92 (s, 3H), 3.89 (s, 3H), 2.62 (ddt, J = 58.0, 15.1, 6.6Hz, 2H), 1.60 (s, 3H), 1.46 (s, 3H). Example 29 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridine-3''-formyloxy-5''-bromo)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-29) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 5-bromo-3-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-29 is a yellow oily substance with a yield of 73.42%. 1 H NMR (600 MHz, Chloroform-d) δ 9.16(d, J = 1.9 Hz, 1H), 8.87 (d, J = 2.3 Hz, 1H), 8.43 - 8.41 (m, 1H), 7.28 (s,1H), 6.79 (d, J = 1.5 Hz, 2H), 6.38 (dd, J = 7.4, 4.9 Hz, 1H), 5.18 (ddd, J =10.1, 5.5, 2.0 Hz, 1H), 3.96 (s, 3H), 3.91 (s, 3H), 2.67 (qt, J = 15.0, 6.6Hz, 2H), 1.70 - 1.68 (m, 3H), 1.59 - 1.56 (m, 3H). Example 30 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(pyridine-2''-formyloxy-4''-chloro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-30) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 4-chloro-2-pyridinecarboxylic acid is used instead of 4-pyridinecarboxylic acid. Compound I-30 is a yellow oily substance with a yield of 83.40%. 1 H NMR (600 MHz, Chloroform-d) δ 8.68(dd, J = 5.2, 0.6 Hz, 1H), 8.09 (dd, J = 2.0, 0.6 Hz, 1H), 7.50 (dd, J = 5.2,2.0 Hz, 1H), 7.31 (d, J = 1.3 Hz, 1H), 6.79 (d, J = 1.2 Hz, 2H), 6.21 (ddd, J= 7.4, 4.7, 1.2 Hz, 1H), 5.20 (ddq, J = 8.6, 7.2, 1.4 Hz, 1H), 3.97 (s, 3H), 3.94 (s, 3H), 2.82 - 2.61 (m, 2H), 1.66 (d, J = 1.4 Hz, 3H), 1.60 (d, J = 1.4Hz, 3H).. Example 31 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-3''-chloro-5''-methoxy)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-31) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3-chloro-5-methoxy-benzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-31 is a yellow oil with a yield of 76.34%. 1 H NMR (600 MHz, Chloroform-d) δ7.63 - 7.62 (m, 1H), 7.46 (dd, J = 2.4, 1.4 Hz, 1H), 7.28 (s, 1H), 7.13 -7.10 (m, 1H), 6.79 (d, J = 1.4 Hz, 2H), 6.30 (dd, J = 7.7, 4.7 Hz, 1H), 5.20 (t, J = 7.3 Hz, 1H), 3.97 (s, 3H), 3.90 (s, 3H), 3.84 (s, 3H), 2.65 (ddt, J =30.1, 15.0, 8.3 Hz, 2H), 1.69 (s, 3H), 1.59 (s, 3H). Example 32 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-4''-nitro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-32) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 4-nitrobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-32 is a yellow oil with a yield of 78.42%. 1 H NMR (600 MHz, Chloroform-d) δ 8.27 (d, J= 8.9 Hz, 2H), 8.19 (d, J = 8.9 Hz, 2H), 6.74 (s, 2H), 6.34 (dd, J = 7.5, 5.0Hz, 1H), 5.16 (t, J = 7.3 Hz, 2H), 3.92 (s, 3H), 3.85 (s, 3H), 2.67 - 2.63(m, 2H), 1.64 (s, 3H), 1.54 (s, 3H). Example 33 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzyl-1''-formyloxy-3'',5''-dibromo)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-33) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3,5-dibromobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-33 is a yellow oil with a yield of 78.24%. 1 H NMR (600 MHz, Chloroform-d) δ 8.15(d, J = 1.8 Hz, 2H), 7.92 (t, J = 1.8 Hz, 1H), 7.33 (d, J = 1.5 Hz, 1H), 6.84(d, J = 1.1 Hz, 2H), 6.37 (dd, J = 7.6, 5.0 Hz, 1H), 5.23 (t, J = 7.3 Hz,1H), 4.01 (s, 3H), 3.97 (s, 3H), 2.72 (dtd, J = 22.5, 14.7, 6.3 Hz, 2H), 1.74(d, J = 1.6 Hz, 3H), 1.65 (d, J = 1.5 Hz, 3H). Example 34 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-(benzene-1''-formyloxy-3'',5''-difluoro)-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-34) having the structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, 3,5-difluorobenzoic acid is used instead of 4-pyridinecarboxylic acid. Compound I-34 is a yellow oily substance with a yield of 78.94%. 1H NMR (600 MHz, Chloroform-d) δ 7.55(dtd, J = 5.8, 4.7, 2.3 Hz, 2H), 7.27 (s, 1H), 7.04 (tt, J = 8.5, 2.4 Hz,1H), 6.78 (d, J = 1.0 Hz, 2H), 6.32 (dd, J = 7.7, 4.8 Hz, 1H), 5.17 (tt, J =7.3, 1.5 Hz, 1H), 3.95 (s, 3H), 3.90 (s, 3H), 2.71 - 2.56 (m, 2H), 1.68 (d, J= 1.5 Hz, 3H), 1.57 (d, J = 1.5 Hz, 3H). Example 35 This embodiment relates to a method for preparing 5,8-dimethoxy-6-(1'-acetoyloxy-4'-methyl-3'-pentene)-1,4-naphthoquinone (I-35) having structural formula (Ⅰ), comprising the following steps: The steps in this embodiment are the same as those in Example 1. In step one, acetic acid is used instead of 4-pyridinecarboxylic acid. Compound I-35 is a yellow powder with a yield of 83.64%. 1 H NMR (600 MHz, Chloroform-d) δ 7.26 (s, 1H), 6.94 -6.58 (m, 2H), 6.14 (dd, J = 7.6, 4.9 Hz, 1H), 5.23 - 5.01 (m, 1H), 3.97 (s,3H), 3.91 (s, 3H), 2.51 (ddt, J = 52.1, 15.0, 6.7 Hz, 2H), 2.13 (s, 3H), 1.68(s, 3H), 1.56 - 1.50 (m, 3H). Test Example 1 This test case involves testing the inhibitory activity of the compounds described in Examples 1-35 against the main protease Mpro of the novel coronavirus.

[0021] Test method: The enzyme inhibitory activity of the compounds was determined using fluorescence resonance energy transfer (FRET) technology (Jin Z, Du X, Xu Y, et al. Structure of Mpro from SARS-CoV-2 and discovery of its inhibitors. Nature. 2020; 582(7811): 289-293), as reported in the literature. The commercially available fluorescently labeled peptide MCA-AVLQSGFR-Lys (Dnp)-Lys-NH2 was used as the substrate (GL Biochem, Shanghai), and enzyme kinetics methods were employed. The incubation system contained SARS-CoV-2 Mpro hydrolase (0.2 μM), the fluorescently labeled peptide (20 μM), and a series of concentrations of the analyte (0-1 μM). The fluorescence intensity of the system was measured using a microplate reader with excitation and detection wavelengths of 320 nm and 405 nm, respectively. Changes in fluorescence intensity were monitored, enzyme kinetic curves were plotted, and the enzyme inhibition rate of the analyte at different concentrations was calculated. All experiments were repeated three times, and the IC5 inhibitory effect of the analyte on the enzyme was calculated using Prism5 software. 50 Value. Shikonin, a previously reported Mpro inhibitor, was used as a positive control.

[0022] Under the same experimental conditions, using shikonin as a positive control, its inhibitory activity IC50 was measured. 50 The value was 13.29 μM, which is consistent with the test results reported in the literature (IC). 50 The value is close to 15.75 μM, indicating the effectiveness of the test system.

[0023] The test results are shown in Table 1 and Figure 2 As shown.

[0024] Figure 2 The IC50 of the compound inhibiting SARS-CoV-2 Mpro was shown. 50 Fitting results; among which, Figure 2 (a) shows the IC50 of shikonin in inhibiting SARS-CoV-2 Mpro. 50 The fitting results, its IC 50 It is 13.29 μM; Figure 2 (b) shows the IC50 of compound I-5 in inhibiting SARS-CoV-2 Mpro. 50 The fitting results, its IC 50 It is 1.080 μM; Figure 2 (c) shows the IC50 of compound I-13 in inhibiting SARS-CoV-2 Mpro. 50 The fitting results, its IC 50 It is 0.3165 μM; Figure 2(d) shows the IC50 of compound I-25 in inhibiting SARS-CoV-2 Mpro. 50 The fitting results, its IC 50 The concentration was 0.6456 μM. As can be seen from the figure, the technology described in this invention yielded a compound with significantly superior activity to the lead compound shikonin; the structural modification resulted in a significant improvement in activity.

[0025] Table 1. Inhibitory activity of compounds against SARS-CoV-2 Mpro Test results show that the compound synthesized in this invention has a significant improvement in inhibiting SARS-CoV-2 Mpro activity compared to shikonin. The prepared compound is a novel and highly efficient SARS-CoV-2 Mpro inhibitor with broad research prospects and development potential.

[0026] Test Example 2 This test case involves the determination of the growth inhibitory activity of the compounds described in Examples 5, 13, and 25 and the positive control drug shikonin on host normal HSF cells.

[0027] Test method: Harvested HSF cells in good growth condition were trypsinized and the cell suspension was adjusted to a suitable concentration with complete culture medium. 5000 cells / well were seeded into 96-well plates and incubated statically for 24 h. After cell attachment, 100 μL of complete culture medium containing the test compound was added to each well, with three replicates for each group. Each 96-well plate included a zero-adjustment well (containing only the compound and culture medium, without cells) and a blank control well (containing only cells and culture medium, without the compound). After 72 h of incubation, 20 μL of MTT solution was added per well, and the plates were incubated in the dark for 4 h. The culture was then terminated, the liquid in the wells was aspirated, and 100 μL of dimethyl sulfoxide was added per well. The plates were shaken at low speed for 10 min until the crystals in the wells were fully dissolved. The absorbance (OD value) of each well was measured at 490 nm. The cell growth inhibition rate was calculated using the following formula: Growth inhibition rate (%) = (1 - OD value of the drug group / OD value of the control group) × 100%.

[0028] The test results are shown in Table 2.

[0029] Table 2. Cytotoxic effects of compounds on normal human HSF cells. The test results above show that, compared with the lead compound shikonin, the derivative obtained by the present invention through structural modification has significantly reduced toxicity to human skin fibroblast HSF, and can effectively avoid host cell damage caused by toxicity.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0031] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A naphthoquinone compound targeting the novel coronavirus, characterized in that, The structural formulas of the naphthoquinone compounds targeting the novel coronavirus are shown in formula (A) or formula (B): ； in, M and M' are absent, or are independently selected from alkyl groups having 1-16 carbon atoms; R and R' are independently selected from one of hydrogen, a straight-chain alkyl group with 1-30 carbon atoms, a branched alkyl group with 1-30 carbon atoms, an aromatic hydrocarbon derivative with 6-60 carbon atoms, or a heterocyclic derivative with 1-60 carbon atoms. The aromatic hydrocarbon derivative is selected from groups containing one or more aromatic ring structures, wherein all hydrogen atoms in the aromatic ring structure are not substituted. or One or more hydrogen atoms at any position on one or more aromatic ring structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups; The heterocyclic derivative is selected from groups containing one or more heterocyclic structures, wherein all hydrogen atoms in the heterocyclic structures are unsubstituted. or One or more hydrogen atoms at any position on one or more heterocyclic structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups; R1, R2, R5, and R6 are independently selected from O and N-OH; R3, R4, R7, and R8 are independently selected from alkoxy groups.

2. The naphthoquinone compound targeting the novel coronavirus according to claim 1, characterized in that, The R and R' are independently selected from one of the following structures: ； in, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 It is independently selected from one of H, halogen atom, nitro group, and alkoxy group.

3. The naphthoquinone compound targeting the novel coronavirus according to claim 1, characterized in that, The structural formula of the naphthoquinone compound targeting the novel coronavirus is shown in formula (I): ； in, M' is absent, or is selected from alkyl groups having 1-16 carbon atoms; R' is selected from one of hydrogen, straight-chain alkyl with 1-30 carbon atoms, branched alkyl with 1-30 carbon atoms, aromatic hydrocarbon derivatives with 6-60 carbon atoms, and heterocyclic derivatives with 1-60 carbon atoms; The aromatic hydrocarbon derivative is selected from groups containing one or more aromatic ring structures, wherein all hydrogen atoms in the aromatic ring structure are not substituted. or One or more hydrogen atoms at any position on one or more aromatic ring structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups; The heterocyclic derivative is selected from groups containing one or more heterocyclic structures, wherein all hydrogen atoms in the heterocyclic structures are unsubstituted. or One or more hydrogen atoms at any position on one or more heterocyclic structures are substituted by one or more halogen, nitro, alkoxy, hydroxy, amino, aryl, olefinic, alkyneic, carboxyl, ester, or cyano groups.

4. Use of the naphthoquinone compound targeting the novel coronavirus according to any one of claims 1-3 in the preparation of a drug against the novel coronavirus 2019-nCoV.

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