L-ribofuranose anti-coronavirus compound and preparation method and application thereof

Abstract

The present invention provides an anti-coronavirus compound and a preparation method and application thereof, wherein the molecular formula of the anti-coronavirus compound is C 28 H 37 N 6 O 8 P, molecular weight is 688.67, and the structural formula of the anti-coronavirus compound is: #imgabs0# and / or #imgabs1#. The anti-coronavirus compound of the present invention can effectively inhibit the activity of coronavirus, can be used as an alternative drug to Monupiravir, and has less cytotoxicity under the premise of having equivalent antiviral activity to Monupiravir.

Description

Technical Field

[0001] The present invention relates to an L-ribofuranosyl type anti-coronavirus compound and a preparation method and application thereof, belonging to the technical field of pharmaceutical chemistry. Background Art

[0002] Coronavirus (English name: Coronavirus) belongs to the order Nidovirales, family Coronaviridae, genus Coronavirus. It is a type of RNA virus with an envelope and a linear single-stranded positive genome. It is a large class of viruses that are widely present in nature. This virus can be seen under an electron microscope with a crown-like outer crown, so it is called Coronavirus (Coronaviridae). In 1975, the Virus Nomenclature Committee officially named the Coronaviridae. It includes rhinovirus, B814 virus, 229E virus, OC43 strain, and those that can infect humans and cause serious respiratory diseases, such as Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS, SARS is a variant of coronavirus and is the pathogen that causes atypical pneumonia) and the new coronavirus (SARS-CoV-2), etc. The symptoms of infection can range from the common cold to severe lung infection.

[0003] Potential targets of COVID-19 are divided into three categories: structural proteins, non-structural proteins and other coronavirus treatment-related targets. Structural proteins include spike protein (Surface Glycoprotein, Spike Protein), E protein (Envelope protein, E Protein), M protein (membrane protein) and N protein (Nucleocapsid Phosphoprotein, N protein). Non-structural proteins include replicase polyprotein 1ab, 3C-like protease, papain-like protease, NSP12 (RDRP, RNA-dependent RNA polymerase), Helicase, Nsp13 (RNA helicase), Nsp14 (Guanine-N7methyltransferase), Nsp15 (Uridylate-specific endoribonuclease), Nsp16 (2'-O-methyl transferase, 2'-O-methyltransferase). Other coronavirus treatment-related targets are mainly ACE2 (angiotensin-converting enzyme 2).

[0004] There are three main types of drugs for the treatment of the new coronavirus, each with a different focus and applicable population: small molecule antiviral drugs can be used for patients with mild, moderate and severe symptoms, neutralizing antibodies are mainly used for patients with mild and moderate symptoms, and immunomodulatory drugs are basically only used for patients with severe symptoms. At present, according to different mechanisms of action, the new coronavirus small molecule antiviral drugs mainly include RNA polymerase inhibitors, 3CL protease inhibitors, etc. There are only four new coronavirus treatment small molecule drugs approved worldwide that act on the new coronavirus polymerase (RdRp), including Gilead Sciences' Remdesivir, Molnupiravir jointly developed by Merck and Ridgeback, Azvudine from Henan Real Biotechnology Co., Ltd., and Deuterium Hydrobromide Remidewei (VV116) from Shanghai Wangshi Biopharmaceutical Technology Co., Ltd. However, so far, no drug has become a specific drug for the new coronavirus or coronavirus.

[0005] In view of this, it is indeed necessary to provide an L-furanose anti-coronavirus compound and a preparation method and application thereof to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide an L-ribofuranose type anti-coronavirus compound with high efficacy and low toxicity, and a preparation method and application thereof.

[0007] To achieve the above-mentioned purpose, the present invention provides an L-ribofuranose anti-coronavirus compound, wherein the anti-coronavirus compound has a molecular formula of C 28 H 37 N6O8P, molecular weight is 688.67, the structural formula of the L-ribofuranose anti-coronavirus compound is:

[0008]

[0009] and / or

[0010]

[0011] As a further improvement of the present invention, the L-ribofuranosyl anti-coronavirus compound is a white solid.

[0012] Another object of the present invention is to provide a pharmaceutical composition having the above-mentioned L-ribofuranosyl anti-coronavirus compound.

[0013] To achieve the above objectives, the present invention provides a pharmaceutical composition comprising a therapeutically effective amount of the above-mentioned L-ribofuranosyl anti-coronavirus compound, stereoisomer or pharmaceutically acceptable salt thereof in unit dosage form, and a pharmaceutically acceptable carrier or excipient.

[0014] Another object of the present invention is to provide the application of the above-mentioned L-ribofuranose type anti-coronavirus compound.

[0015] To achieve the above objectives, the present invention provides the use of the above-mentioned L-ribofuranose anti-coronavirus compound in the preparation of drugs for preventing and / or treating coronavirus-related diseases.

[0016] As a further improvement of the present invention, the coronavirus includes 2019-nCoV, HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, SARS-CoV and MERS-CoV.

[0017] Another object of the present invention is to provide a method for preparing an L-ribofuranose type anti-coronavirus compound with high efficacy and low toxicity.

[0018] To achieve the above-mentioned object of the invention, the present invention provides a method for preparing an anti-coronavirus compound, comprising the following steps:

[0019]

[0020] Under nitrogen protection, compound 13 was dissolved in a mixed solvent of tetrahydrofuran and water, trifluoroacetic acid was added after cooling, and then reacted at room temperature; after the reaction was completed as monitored by thin layer chromatography and LCMS, it was neutralized with saturated sodium bicarbonate solution to pH 7-8, concentrated, passed through a C18 reverse phase column, and freeze-dried to obtain target compound 1 and target compound 2, wherein target compound 1 and target compound 2 are chiral compounds.

[0021] As a further improvement of the present invention, the preparation method of compound 13 comprises the following steps:

[0022]

[0023] Under nitrogen protection, compound 9 was dissolved in dimethylformamide, cooled and then added with a dimethylformamide solution of t-BuMgCl for reaction, then added with a dimethylformamide solution of compound 12 for heating for reaction, and after completion of the reaction monitored by thin layer chromatography and LCMS, the reaction solution was poured into a saturated ammonium chloride solution, extracted with ethyl acetate, and the organic phase was dried, concentrated, and subjected to column chromatography to obtain compound 13, which was a yellow solid.

[0024] As a further improvement of the present invention, the preparation method of compound 9 comprises the following steps:

[0025] Step 1:

[0026]

[0027] Under nitrogen protection and ice-water bath conditions, concentrated sulfuric acid was added dropwise to a methanol solution containing compound 1 to react. After the reaction was completed as monitored by thin layer chromatography, it was neutralized with a saturated sodium bicarbonate solution to pH 7-8, and then dried, filtered, concentrated, and column chromatographed to obtain compound 2, wherein compound 1 contained L-ribose and compound 2 was a yellow oil;

[0028] Step 2:

[0029]

[0030] Under nitrogen protection and ice-water bath conditions, 60% sodium hydrogen was added to a dimethylformamide solution containing compound 2, and then benzyl bromide was added dropwise; after the benzyl bromide was added dropwise, the reaction was allowed to proceed overnight at room temperature. After the reaction was completed by monitoring by thin layer chromatography, the reaction solution was poured into an ice-water solution of saturated ammonium chloride and extracted with ethyl acetate, wherein the organic phase was washed, dried, filtered, concentrated, and column chromatographed to obtain compound 3, wherein the compound 3 was a yellow oil 3;

[0031] Step 3:

[0032]

[0033] Under nitrogen protection, hydrochloric acid is added dropwise to an acetic acid solution containing compound 3, followed by heating for reaction; after the reaction is completed, the reaction solution is concentrated under reduced pressure, and after concentration, it is dissolved with ethyl acetate and water, and the organic phase is washed, dried, filtered, and concentrated to obtain compound 4;

[0034] Step 4:

[0035]

[0036] Compound 4 was concentrated and dissolved in dry dimethyl sulfoxide, acetic anhydride was added, and the reaction was carried out at room temperature under nitrogen protection until completion. The reaction solution was concentrated under reduced pressure and dissolved in ethyl acetate. After washing, drying, filtering, concentrating under reduced pressure, and column chromatography, compound 5 was obtained. The compound 5 was a yellow oil;

[0037] Step 5:

[0038]

[0039] Under nitrogen protection, trimethylsilyl chloride is added to a dry tetrahydrofuran solution containing 4-amino-7-bromopyrrolo[2,1-F][1,2,4]triazine, and the reaction is carried out at room temperature. After the reaction solution is cooled to -78°C, n-BuLi n-hexane solution is added dropwise to the reaction solution, and then compound 5 dissolved in dry tetrahydrofuran is added dropwise to the reaction solution for reaction. After the reaction is completed, acetic acid is added to quench the reaction, and the mixture is concentrated under reduced pressure and then dissolved in dichloromethane and water. The organic phase is washed, dried, filtered, concentrated, and subjected to column chromatography to obtain compound 6, which is a yellow solid.

[0040] Step 6:

[0041]

[0042] Under nitrogen protection, compound 6 was dissolved in a dry dichloromethane solution, cooled, trimethylsilyl cyanide was added, and trimethylsilyl trifluoromethanesulfonate was added to the reaction solution for reaction. After the reaction was completed, a saturated sodium bicarbonate solution was added to quench and stir, and the organic phase and the aqueous phase were separated, and the organic phase was dried, filtered, concentrated, and column chromatographed to obtain compound 7, which was a yellow solid.

[0043] Step 7:

[0044]

[0045] Under nitrogen protection, compound 7 was dissolved in a dichloromethane solution, and after cooling, a n-hexane solution containing BCl3 was added dropwise, and then cooled to react. After the reaction was completed, methanol was added to quench, and the mixture was concentrated under reduced pressure and separated by a C18 reverse phase column to obtain compound 8, which was a light yellow solid.

[0046] Step 8:

[0047]

[0048] Under nitrogen protection, compound 8 and 2,2'-dimethoxypropane were dissolved in acetone, concentrated sulfuric acid was added, and the reaction was heated. After the reaction was completed as monitored by thin layer chromatography, sodium bicarbonate was used to neutralize to pH 7-8. After concentration and column chromatography, compound 9 was obtained, which was a yellow solid.

[0049] As a further improvement of the present invention, the preparation method of compound 12 comprises the following steps:

[0050] Step 1:

[0051]

[0052] Under nitrogen protection, compound 10 and 2-ethyl-1-butanol were dissolved in toluene, p-toluenesulfonic acid was added and heated, and water was separated by a water separator and then reacted. After the reaction was completed by thin layer chromatography and LCMS detection, the mixture was concentrated, neutralized with a saturated sodium bicarbonate solution to pH 7-8, and extracted with dichloromethane. The organic phase was dried, concentrated, and subjected to column chromatography to obtain compound 11, wherein the compound 10 was 2-methylalanine, and the compound 11 was a white solid;

[0053] Step 2:

[0054]

[0055] Under nitrogen protection, phosphorus oxychloride and the p-toluenesulfonate of compound 11 were dissolved in dichloromethane, cooled, and triethylamine was added dropwise for reaction, and then a dichloromethane solution of triethylamine and ethyl o-hydroxybenzoate was added for reaction, and then triethylamine and p-nitrophenol were added for reaction. After the reaction was completed by monitoring by thin layer chromatography and LCMS, the product was concentrated and passed through a C18 reverse phase column to obtain compound 12, wherein the compound 11 was 2-methylalanine 2-ethylbutyl ester, and the compound 12 was a yellow oil.

[0056] The beneficial effects of the present invention are as follows: the present invention provides an L-ribofuranose type anti-coronavirus compound and a preparation method and application thereof. The L-ribofuranose type anti-coronavirus compound can effectively inhibit the activity of coronavirus and can be used as an alternative drug to Monupiravir. It has less cytotoxicity while having equivalent antiviral activity to Monupiravir. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is the nuclear magnetic spectrum of the L-ribofuranosyl anti-coronavirus compound of the present invention.

[0058] Figure 2 It is the LCMS spectrum of the L-ribofuranosyl anti-coronavirus compound of the present invention.

[0059] Figure 3 This is the NMR spectrum of the target compound 1.

[0060] Figure 4 This is the NMR spectrum of target compound 2.

[0061] Figure 5 This is the NMR spectrum of compound 13.

[0062] Figure 6 This is the NMR spectrum of compound 2.

[0063] Figure 7 This is the NMR spectrum of compound 3.

[0064] Figure 8This is the NMR spectrum of compound 5.

[0065] Fig. 9 This is the NMR spectrum of compound 6.

[0066] Fig.10 This is the NMR spectrum of compound 7.

[0067] Fig.11 This is the NMR spectrum of compound 8.

[0068] Fig.12 This is the NMR spectrum of compound 9.

[0069] Fig.13 This is the NMR spectrum of compound 11.

[0070] Fig.14 This is the NMR spectrum of compound 12. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0072] It should be noted here that in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0073] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0074] As shown in the figure, the present invention provides an L-furanose type anti-coronavirus compound, the molecular formula of the anti-coronavirus compound is C 28 H 37 N6O8P, molecular weight is 688.67, the structural formula of the L-ribofuranose anti-coronavirus compound is:

[0075]

[0076] and / or

[0077]

[0078] Furthermore, the L-ribofuranose anti-coronavirus compound is a chiral compound, including target compound 1 and target compound 2. That is, the furanose ring of the L-ribofuranose anti-coronavirus compound is in L configuration.

[0079] Furthermore, the L-ribofuranose-type anti-coronavirus compound is a white solid and can be formulated into various preparation forms well known in the art, such as tablets, capsules, granules, pills, oral solutions, and injections according to the specific administration method.

[0080] The present invention further provides a pharmaceutical composition having the above-mentioned L-ribofuranose anti-coronavirus compound. The pharmaceutical composition comprises the above-mentioned L-ribofuranose anti-coronavirus compound, stereoisomer or pharmaceutically acceptable salt thereof in a unit dosage form in a therapeutically effective amount, and a pharmaceutically acceptable carrier or excipient.

[0081] The present invention further provides the use of the L-ribofuranose anti-coronavirus compound and the use of the L-ribofuranose anti-coronavirus compound in the preparation of drugs for preventing and / or treating coronavirus-related diseases.

[0082] Furthermore, the coronavirus includes 2019-nCoV, HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, SARS-CoV and MERS-CoV. Among them, 2019-nCoV can cause COVID-19, SARS-CoV can cause severe acute respiratory syndrome, and MERS-CoV can cause Middle East respiratory syndrome.

[0083] Furthermore, the L-ribofuranose-type anti-coronavirus compound is also used to prepare drugs for preventing and / or treating mutant strains of coronavirus.

[0084] The present invention further provides a method for preparing an L-ribofuranose type anti-coronavirus compound with high efficacy and low toxicity. The preparation method has mild conditions, is easy to synthesize, and is suitable for industrial production.

[0085] To achieve the above-mentioned object of the invention, the present invention provides a method for preparing an anti-coronavirus compound, comprising the following steps:

[0086]

[0087] Under nitrogen protection, compound 13 was dissolved in a mixed solvent of tetrahydrofuran (THF) and water, trifluoroacetic acid was added after cooling, and then reacted at room temperature; after the reaction was completed as monitored by thin layer chromatography (TLC) and LCMS, it was neutralized with a saturated sodium bicarbonate solution to pH 7-8, concentrated, passed through a C18 reverse phase column, and freeze-dried to obtain target compounds 1 and target compound 2, wherein target compound 1 and target compound 2 are chiral compounds, and target compound 1 and target compound 2 are both white solids.

[0088] Preferably, under nitrogen protection, compound 13 (550 mg, 0.755 mmol, 1.0 eq) is dissolved in a mixed solvent (5.5 mL, THF / H2O=10:1), cooled to 0°C, 4.5 mL of trifluoroacetic acid is added, and then reacted at room temperature for 24 hours. The reaction process is monitored by thin layer chromatography (TLC) and LCMS. The developing solvent of TLC is dichloromethane (DCM) and methanol (MeOH), and DCM:MeOH=10:1, and detection is performed at UV254 nm. After the reaction is completed, it is neutralized to pH 7-8 with a saturated sodium bicarbonate solution, concentrated, passed through a C18 reverse phase column (MeCN / H2O 0-100%), and lyophilized to obtain a mixture of target compound 1 and target compound 2, which is a white solid.

[0089] In this embodiment, the weight of the mixture is 385 mg. In other embodiments, due to different dosages of the compounds used, the weight of the mixture obtained is also different.

[0090] Preferably, in this embodiment, the L-furanosyl ribose anti-coronavirus compound obtained by the reaction is a mixture of target compound 1 and target compound 2, named β-L-1-cyano-2-methyl styrene, with a molecular weight of 689.3 and NMR data of:

[0091] 1 H NMR(400MHz, DMSO-d6)δ8.35–8.01(d,J=57.5Hz,3H),7.98–7.94(s,1H),7.77–7.71(d,J=7.7Hz,1H),7.58–7.45(m,2H),7.3 0–7.23(m,1H),6.97–6.93(s,1H),6.89–6.84(dd,J=7.5,3.4Hz,1H),5.83–5.76(d,J=9.5Hz,1H),4.68–4.63(d,J=4.9Hz,1H ),4.32–4.23(qd,J=7.0,3.5Hz,4H),4.23–4.14(dt,J=10.5,5.4Hz,1H),4.00–3.92(m,1H),3.89–3.85(dt,J=5.4,2.4Hz,2H ),1.42–1.36(m,1H),1.34–1.30(d,J=3.3Hz,6H),1.30–1.20(qd,J=8.7,7.9,4.7Hz,8H),0.82–0.76(tt,J=7.6,2.1Hz,6H).

[0092] The NMR and LCMS spectra of the mixture are shown in Figure 1 and Figure 2 .

[0093] The mixture can be separated to obtain target compound 1 and target compound 2.

[0094] The molecular weight of target compound 1 is 689.3, and the NMR data are:

[0095] 1 H NMR(400MHz, DMSO-d6)δ8.01–7.83(s,3H),7.77–7.70(d,J=7.5Hz,1H),7.56–7.45(m,2H),7.30–7.21( m,1H),6.92–6.87(d,J=4.5Hz,1H),6.87–6.82(d,J=4.5Hz,1H),6.34–6.28(d,J=6.0Hz,1H),5.81–5.74 (d,J=9.5Hz,1H),5.42–5.31(s,1H),4.70–4.63(m,1H),4.35–4.13(m,5H),3.98–3.92(t,J=5.8Hz,1H) ,3.92–3.83(m,2H),1.45–1.36(p,J=6.2Hz,1H),1.36–1.19(m,12H),0.84–0.75(td,J=7.5,2.4Hz,6H).

[0096] The NMR data of target compound 2 are:

[0097] 1H NMR(400MHz, DMSO-d6)δ8.01–7.79(s,3H),7.77–7.71(dd,J=7.8,1.5Hz,1H),7.58–7.50(ddd,J=8.8,7.3,1.8Hz,1H),7.50–7.44(d, J=8.3Hz,1H),7.31–7.23(t,J=7.4Hz,1H),6.91–6.86(d,J=4.5Hz,1H),6.86–6.80(d,J=4.5Hz,1H),6.34–6.28(d,J=6.1Hz,1H),5.81 –5.74(d,J=9.5Hz,1H),5.40–5.34(d,J=5.7Hz,1H),4.71–4.64(m,1H),4.34–4.21(q,J=7.1Hz,4H),4.21–4.12(dd,J=10.8,5.6Hz,1H ),4.01–3.93(q,J=5.6Hz,1H),3.92–3.84(m,2H),1.45–1.36(p,J=6.2Hz,1H),1.35–1.18(m,13H),0.83–0.74(td,J=7.5,1.6Hz,6H).

[0098] The NMR spectra of target compound 1 and target compound 2 are shown in Figure 3 and Figure 4 .

[0099] It should be noted that compound 13 required for preparing L-ribofuranosyl anti-coronavirus compounds can be obtained by self-preparation or by purchase, and the present invention is not limited to this.

[0100] Furthermore, in this embodiment, compound 13 was independently developed and prepared. The preparation method of compound 13 comprises the following steps:

[0101]

[0102] Under nitrogen protection, compound 9 was dissolved in dimethylformamide, cooled and then added with a dimethylformamide solution of t-BuMgCl for reaction, then added with a dimethylformamide solution of compound 12 for heating for reaction, and after completion of the reaction monitored by thin layer chromatography and LCMS, the reaction solution was poured into a saturated ammonium chloride solution, extracted with ethyl acetate, and the organic phase was dried, concentrated, and subjected to column chromatography to obtain compound 13, which was a yellow solid.

[0103] Preferably, under nitrogen protection, compound 9 (500 mg, 1.51 mmol, 1.0 eq) is dissolved in 6 mL of dry dimethylformamide (DMF), cooled to 0°C, 1M t-BuMgCl in DMF solution (3.0 mL, 3.0 mmol, 2.0 eq) is added dropwise, and then reacted at 0°C for 30 minutes, and then compound 12 (1.62 g, 3.02 mmol, 2.0 eq) in DMF solution is added dropwise, and finally heated to 50°C for 2 hours. After the reaction is completed by TLC (DCM: MeOH = 10: 1, UV254 nm) and LCMS monitoring, the reaction solution is poured into a saturated ammonium chloride solution, extracted three times with ethyl acetate, and the organic phase is dried with anhydrous sodium sulfate, concentrated, and column chromatographed (MeOH / DCM 0-20%) to obtain compound 13, which is a yellow solid with a molecular weight of 729.3 and a weight of 600 mg in this embodiment.

[0104] The NMR data of compound 13 are:

[0105] 1 H NMR (400MHz, DMSO-d6) δ8.05–7.85(s,3H),7.76–7.69(d,J=7.8Hz,1H),7.53–7.48(m,1H),7.46–7.41(d,J=8.3Hz,1H),7.30–7.22(t,J=7.1Hz,1H) ,6.92–6.88(dd,J=4.6,1.9Hz,1H),6.87–6.83(t,J=4.9Hz,1H),5.87–5. 78(dd,J=12.8,9.5Hz,1H),5.43–5.31(dd,J=22.5,6.5Hz,1H),5.02–4.90 (m,1H),4.59–4.50(d,J=3.2Hz,1H),4.29–4.20(dd,J=7.1,4.0Hz,2H),4 .20–4.14(t,J=6.3Hz,2H),4.12–4.06(d,J=5.2Hz,1H),3.89–3.84(dd,J= 5.8,3.3Hz,2H),1.67–1.61(s,3H),1.38–1.33(s,4H),1.33–1.28(d,J=3 .2Hz,7H),1.28–1.22(d,J=1.7Hz,7H),0.82–0.75(dd,J=7.3,1.1Hz,6H).

[0106] The NMR spectrum of compound 13 is shown in Figure 5 .

[0107] It should be noted that the compounds 9 and 12 required for preparing the compound 13 can be obtained by self-preparation or by purchase, and the present invention is not limited thereto.

[0108] In this example, compound 9 and compound 12 were both independently developed and prepared.

[0109] Furthermore, the preparation method of compound 9 comprises the following steps:

[0110] Step 1:

[0111]

[0112] Under nitrogen protection and ice-water bath conditions, concentrated sulfuric acid was added dropwise to a methanol solution containing compound 1 to react. After the reaction was completed as monitored by thin layer chromatography, it was neutralized with a saturated sodium bicarbonate solution to pH 7-8. The solution was dried, filtered, concentrated, and subjected to column chromatography to obtain compound 2, wherein the compound 1 was L-ribose and the compound 2 was a yellow oil.

[0113] Preferably, under nitrogen protection and ice-water bath conditions, concentrated sulfuric acid (3.0 mL, 57.09 mmol, 0.33 eq) is added dropwise to a dry methanol (260 mL) solution containing L-ribose (26 g, 0.173 mol, 1.0 eq). After the addition of concentrated sulfuric acid, the reaction is carried out at room temperature for 5 hours. After the reaction is completed by monitoring by TLC (PE: EA = 5: 1, UV 254 nm), the reaction is neutralized with a saturated sodium bicarbonate solution to pH 7-8, dried, filtered, concentrated, and column chromatographed (EA / PE 0-50%) to obtain compound 2, which is a yellow oil with a molecular weight of 332.1 and a weight of 29.65 g in this embodiment.

[0114] The NMR data of compound 2 are:

[0115] 1 H NMR(400MHz, Methanol-d4)δ4.77–4.72(m,1H),4.06–4.00(m,1H),4.00–3.95(dd,J=12.4,3.8Hz,1H),3.9 5–3.91(m,1H),3.75–3.69(dd,J=11.7,3.5Hz,1H),3.57–3.51(dd,J=11.8,6.4Hz,1H),3.37–3.34(s,3H).

[0116] The NMR spectrum of compound 2 is shown in Figure 6 .

[0117] Step 2:

[0118]

[0119] Under nitrogen protection and ice-water bath conditions, 60% sodium hydrogen was added to a dimethylformamide solution containing compound 2, and then benzyl bromide was added dropwise; after the benzyl bromide was added dropwise, the reaction was allowed to proceed overnight at room temperature. After the reaction was completed by monitoring by thin layer chromatography, the reaction solution was poured into an ice-water solution of saturated ammonium chloride and extracted with ethyl acetate, wherein the organic phase was washed, dried, filtered, concentrated, and column chromatographed to obtain compound 3, wherein the compound 3 was a yellow oil 3.

[0120] Under nitrogen protection and ice-water bath conditions, 60% sodium hydrogen (31.6 g, 0.79 mmol, 5.0 eq) was added to a dry DMF (260 mL) solution containing compound 2 (26 g, 0.158 mol, 1.0 eq) in three batches, and then benzyl bromide (108.01 g, 0.632 mol, 4.0 eq) was added dropwise. After the benzyl bromide was added dropwise, the reaction was allowed to proceed overnight at room temperature. After the reaction was completed as monitored by TLC (PE: EA = 5: 1, UV 254 nm), the reaction solution was poured into an ice-water solution of saturated ammonium chloride and extracted three times with ethyl acetate. The organic phase was washed with brine, dried with anhydrous sodium sulfate, filtered, concentrated, and column chromatographed (EA / PE 0-30%) to obtain compound 3, which was a yellow oil 3 with a molecular weight of 452.34 and a weight of 43.29 g in this embodiment.

[0121] The NMR data of compound 3 are:

[0122] 1 H NMR(400MHz,Chloroform-d)δ7.42–7.22(m,15H),4.95–4.90(s,1H),4.71–4.60(q,J=11.9Hz,2H),4.59–4.52(m,3H),4.49–4.42(d,J=11.8Hz,1H ),4.39–4.32(m,1H),4.06–3.99(dd,J=7.1,4.7Hz,1H),3.88–3.82(m,1H ), 3.65–3.59(dd,J=10.6,3.7Hz,1H), 3.56–3.49(dd,J=10.6,5.8Hz,1H).

[0123] The NMR spectrum of compound 3 is shown in Figure 7 .

[0124] Step 3:

[0125]

[0126] Under nitrogen protection, hydrochloric acid was added dropwise to an acetic acid solution containing compound 3, and the mixture was heated to react. After the reaction was completed, the reaction solution was concentrated under reduced pressure, and then dissolved with ethyl acetate and water. The organic phase was washed, dried, filtered, and concentrated to obtain compound 4.

[0127] Preferably, under nitrogen protection, 1M hydrochloric acid (109.6mL, 109.6mmol, 1.1eq) is added dropwise to a solution of acetic acid (430mL) containing compound 3 (43.29g, 99.62mmol, 1.0eq). After the addition is completed, the reaction solution is heated to 80°C for 4 hours. After the reaction is completed, the reaction solution is concentrated under reduced pressure, and after concentration, it is dissolved with ethyl acetate and water, and the organic phase is washed with sodium bicarbonate solution, washed with saturated brine, dried with anhydrous sodium sulfate, filtered, concentrated, and a crude compound 4 is obtained, which is directly used in the next step.

[0128] Step 4:

[0129]

[0130] Compound 4 was concentrated and dissolved in dry dimethyl sulfoxide (DMSO), acetic anhydride was added, and the reaction was completed at room temperature under nitrogen protection. The reaction solution was concentrated under reduced pressure and dissolved in ethyl acetate. After washing, drying, filtering, concentrating under reduced pressure, and column chromatography, compound 5 was obtained. The compound 5 was a yellow oil.

[0131] Compound 4 was concentrated and dissolved in 220 mL of dry DMSO, and acetic anhydride (132 mL, 1.045 mol, 1.5 eq) was added. The reaction was allowed to react overnight at room temperature under nitrogen protection. After the reaction was completed, the reaction solution was concentrated under reduced pressure, dissolved in ethyl acetate, washed with water, sodium bicarbonate solution, saturated brine, dried, filtered, concentrated under reduced pressure, and column chromatographed (EA / PE 0-100%, UV 254 nm) to obtain compound 5. Compound 5 was a yellow oil with a molecular weight of 436.3 and a weight of 33.63 g in this embodiment.

[0132] The NMR data of compound 5 are:

[0133] 1 H NMR (400MHz, DMSO-d6) δ7.42–7.18 (m, 15H), 4.77–4.55 (m, 6H), 4.51–4.46 (s, 2H), 4.33–4.27 (d, J = 5.4Hz, 1H), 3.70–3.65 (d, J = 3.4Hz, 2H).

[0134] The NMR spectrum of compound 5 is shown in Figure 8 .

[0135] Step 5:

[0136]

[0137] Under nitrogen protection, trimethylsilyl chloride (TMSCl) was added to a dry tetrahydrofuran solution containing 4-amino-7-bromopyrrolo[2,1-F][1,2,4]triazine, and the reaction was carried out at room temperature. After the reaction solution was cooled to -78°C, n-BuLi n-hexane solution was added dropwise to the reaction solution, and then compound 5 dissolved in dry tetrahydrofuran was added dropwise to the reaction solution to react. After the reaction was completed, acetic acid was added to quench, and the mixture was concentrated under reduced pressure and dissolved in dichloromethane and water. The organic phase was washed, dried, filtered, concentrated, and subjected to column chromatography to obtain compound 6, which was a yellow solid.

[0138] Preferably, under nitrogen protection, TMSCl (19.52 g, 179.67 mmol, 2.2 eq) is added to a dry tetrahydrofuran (175 mL) solution containing 4-amino-7-bromopyrrolo[2,1-F][1,2,4]triazine (17.4 g, 81.67 mmol, 1.0 eq). After the addition, the reaction is allowed to react at room temperature for 20 minutes, then the reaction solution is cooled to -78°C, 1.6 M n-BuLi hexane solution is added dropwise to the reaction solution for 10 minutes, and compound 5 (34.18 g, 81.67 mol, 1.0 eq) is dissolved in dry tetrahydrofuran and added dropwise to the reaction solution. After the addition is completed, the reaction is allowed to react at -78°C for 4 hours. After the reaction was completed, acetic acid was added to quench the reaction and the mixture was reacted at -78°C for 10 minutes, and the reaction was concentrated under reduced pressure. After concentration, the mixture was dissolved with dichloromethane and water. The organic phase was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, concentrated, and column chromatography (ethyl acetate / petroleum ether 0-100%, UV254nm) was performed to obtain compound 6, which was a yellow solid with a molecular weight of 553.3 and a weight of 7.36 g in this embodiment.

[0139] The NMR data of compound 6 are:

[0140] 1H NMR (400MHz, DMSO-d6) δ8.12–8.00(s,2H),8.00–7.96(s,1H),7.79–7.76(s,2H),7.74–7.61(d,J=22.5Hz,4H),7.60–7.57(dd,J=2.6, 1.6Hz,2H),7.37–7.22(m,13H),7.18–7.11(m,3H),7.02–6.97(dd,J=7.4,2.2Hz,2H),6.95–6.92(d,J=4.8Hz,1H),6.87–6.83(dd,J=4 .3,1.6Hz,2H),6.62–6.57(dd,J=4.3,2.6Hz,2H),5.42–5.35(d,J=6.0Hz,1H),5.07–5.01(d,J=5.2Hz,1H),4.60–4.54(dt,J=11.7,2. 5Hz, 2H), 4.48–4.43 (m, 3H), 3.95–3.90 (dd, J=6.0, 4.4Hz, 1H), 3.72–3.66 (dd, J=10.1, 3.5Hz, 1H), 3.51–3.43 (dd, J=10.1, 6.4Hz, 1H).

[0141] The NMR spectrum of compound 6 is shown in Fig. 9 .

[0142] Step 6:

[0143]

[0144] Under nitrogen protection, compound 6 was dissolved in a dry dichloromethane solution. After cooling, trimethylsilyl cyanide (TMSCN) was added, and then trimethylsilyl trifluoromethanesulfonate (TMSOTf) was added to the reaction solution for reaction. After the reaction was completed, saturated sodium bicarbonate solution was added to quench and stirred. After the organic phase and the aqueous phase were separated, the organic phase was dried, filtered, concentrated, and column chromatographed to obtain compound 7, which was a yellow solid.

[0145] Preferably, under nitrogen protection, compound 6 (7.75 g, 14.02 mmol, 1.0 eq) is dissolved in dry dichloromethane (75 mL) solution, cooled to -78 ° C, and TMSCN (5.38 g, 54.23 mmol, 3.87 eq) is added. After the addition is complete, the reaction is carried out for 10 minutes, and then TMSOTf (11.5 mL, 63.09 mmol, 4.5 eq) is added to the reaction solution and reacted for 2 hours. After the reaction is completed, saturated sodium bicarbonate solution is added to quench and stir for 10 minutes, the organic phase is separated, and the aqueous phase is extracted three times with dichloromethane. The combined organic phase is dried with anhydrous magnesium sulfate, filtered, concentrated, and column chromatographed (methanol / dichloromethane 0-20%, UV254 nm) to obtain compound 7, which is a yellow solid with a molecular weight of 562.3 and a weight of 2.90 g in this embodiment.

[0146] The NMR data of compound 7 are:

[0147] 1 H NMR (400MHz, DMSO-d6) δ8.01–7.82 (d, J=19.5Hz, 3H), 7.37–7.22 (m, 15H), 6.88–6.85 (d, J=4. 6Hz,1H),6.77–6.74(d,J=4.6Hz,1H),4.92–4.89(d,J=5.0Hz,1H),4.87–4.82(d,J=11.7Hz,1 H),4.79–4.74(d,J=11.7Hz,1H),4.56–4.51(dd,J=9.0,3.9Hz,2H),4.51–4.48(d,J=3.7Hz,2 H),4.14–4.09(m,1H),3.72–3.66(dd,J=11.1,3.6Hz,1H),3.61–3.56(dd,J=11.0,4.7Hz,1H).

[0148] The NMR spectrum of compound 7 is shown in Fig.10 .

[0149] Step 7:

[0150]

[0151] Under nitrogen protection, compound 7 was dissolved in a dichloromethane solution, and after cooling, a n-hexane solution containing BCl3 was added dropwise, followed by cooling for reaction. After the reaction was completed, methanol was added for quenching, the mixture was concentrated under reduced pressure, and separated by a C18 reverse phase column to obtain compound 8, which was a light yellow solid.

[0152] Preferably, under nitrogen protection, compound 7 (2.8 g, 4.99 mmol, 1.0 eq) is dissolved in a dry dichloromethane (30 mL) solution, cooled to -20 ° C, and a 1M BCl3 n-hexane solution (29.81 mL, 29.81 mmol, 6.0 eq) is added dropwise. After addition, the mixture is cooled to -78 ° C and reacted for 2 hours. After the reaction is completed, methanol is added at -78 ° C for quenching, concentrated under reduced pressure, and separated by a C18 reverse phase column (acetonitrile / water 0-100%, UV254 nm) to obtain compound 8, which is a light yellow solid, and its weight in this embodiment is 0.99 g.

[0153] The NMR data of compound 8 are:

[0154] 1 H NMR (400MHz, DMSO-d6) δ8.04–7.80 (d, J=5.2Hz, 3H), 6.94–6.86 (m, 2H), 6.14–6.06 (d,J=6.3Hz,1H),5.22–5.15(d,J=5.3Hz,1H),4.95–4.88(dd,J=6.3,5.2Hz,1H),4 .67–4.62(dd,J=6.3,5.1Hz,1H),4.08–4.03(m,1H),3.98–3.93(q,J=5.3Hz,1H),3 .68–3.60(ddd,J=12.2,5.2,3.4Hz,1H), 3.54–3.47(ddd,J=12.2,6.3,4.5Hz,1H).

[0155] The NMR spectrum of compound 8 is shown in Fig.11 .

[0156] Step 8:

[0157]

[0158] Under nitrogen protection, compound 8 and 2,2'-dimethoxypropane were dissolved in acetone, concentrated sulfuric acid was added, and the reaction was heated. After the reaction was completed as monitored by thin layer chromatography, sodium bicarbonate was used to neutralize to pH 7-8. After concentration and column chromatography, compound 9 was obtained, which was a yellow solid.

[0159] Preferably, under nitrogen protection, compound 8 (500 mg, 1.72 mmol, 1.0 eq) and 2,2'-dimethoxypropane (0.95 mL, 7.74 mmol, 4.5 eq) are dissolved in acetone (10 mL), concentrated sulfuric acid (0.12 mL, 2.24 mmol, 1.3 eq) is added, and heated to 50°C for 1 hour. After the reaction is completed by monitoring by TLC (DCM: MeOH = 10: 1, UV 254 nm), it is neutralized with sodium bicarbonate to pH 7-8, concentrated, and column chromatographed (MeOH / DCM 0-20%) to obtain compound 9, which is a yellow solid with a molecular weight of 332.2 and a weight of 520 mg in this embodiment.

[0160] The NMR data of compound 9 are:

[0161] 1 H NMR(400MHz, DMSO-d6)δ8.06–7.82(d,J=12.9Hz,3H),6.93–6.87(m,2H),5.40–5.34(d,J=6.6Hz,1H),5.03–4.98(t,J=5.7Hz,1H),4.91–4.8 6(dd,J=6.6,3.1Hz,1H),4.33–4.28(td,J=5.3,3.0Hz,1H),3.59–3.45(dtd,J=17.4,11.6,5.6Hz,2H),1.68–1.57(s,3H),1.41–1.32(s,3H).

[0162] The NMR spectrum of compound 9 is shown in Fig.12 .

[0163] Furthermore, the preparation method of compound 12 comprises the following steps:

[0164] Step 1:

[0165]

[0166] Under nitrogen protection, compound 10 (2-methylalanine) and 2-ethyl-1-butanol were dissolved in toluene, heated after adding p-toluenesulfonic acid, reacted after separating water with a water separator, and after the reaction was completed by thin layer chromatography and LCMS detection, concentrated, neutralized with saturated sodium bicarbonate solution to pH 7-8, extracted with dichloromethane, and the organic phase was dried, concentrated, and column chromatographed to obtain compound 11, wherein the compound 10 is 2-methylalanine and the compound 11 is a white solid.

[0167] Preferably, under nitrogen protection, 2-methylalanine (20g, 194mmol, 1.0eq) and 2-ethyl-1-butanol (29.7g, 291mmol, 1.5eq) are dissolved in toluene (200mL), p-toluenesulfonic acid (37g, 213.4mmol, 1.1eq) is added, heated to 130°C and separated with a water separator, and reacted for 16 hours. After the reaction is completed by TLC (DCM: MeOH = 10: 1, UV254nm / I2) and LCMS detection, it is concentrated, neutralized with a saturated sodium bicarbonate solution to pH 7-8, extracted with dichloromethane three times, and the organic phase is dried with anhydrous sodium sulfate and concentrated to obtain a crude product. The crude product is subjected to column chromatography (MeOH / DCM 0-20%) to obtain compound 11. The compound 11 is a white solid with a molecular weight of 188.3, ​​a weight of 28g in this embodiment, and a yield of 40.2%.

[0168] The NMR data of compound 11 are:

[0169] 1 H NMR (400MHz, DMSO-d6) δ7.54–7.47(m,2H),7.13(d,J=8.0Hz,2H),4.05(d,J=5.5Hz,2H),2.30 (s,3H),1.52(p,J=6.1Hz,1H),1.38(s,6H),1.35–1.27(m,4H),0.85(dt,J=13.2,7.4Hz,6H).

[0170] The NMR spectrum of compound 11 is shown in Fig.13 .

[0171] Step 2:

[0172]

[0173] Under nitrogen protection, phosphorus oxychloride and the p-toluenesulfonate of compound 11 were dissolved in dichloromethane, cooled, and triethylamine was added dropwise for reaction, and then a dichloromethane solution of triethylamine and ethyl o-hydroxybenzoate was added for reaction, and then triethylamine and p-nitrophenol were added for reaction. After the reaction was completed by monitoring by thin layer chromatography and LCMS, the product was concentrated and passed through a C18 reverse phase column to obtain compound 12, wherein the compound 11 was 2-methylalanine 2-ethylbutyl ester, and the compound 12 was a yellow oil.

[0174] Under nitrogen protection, phosphorus oxychloride (1.0 g, 6.52 mmol, 1.0 eq) and 2-methylalanine 2-ethylbutyl ester toluenesulfonate (2.46 g, 6.85 mmol, 1.05 eq) were dissolved in dry dichloromethane (10 mL), cooled to -70°C, and triethylamine (1.38 g, 13.69 mmol, 2.1 eq) was added dropwise and reacted for three hours. A dichloromethane solution of triethylamine (0.69 g, 6.85 mmol, 1.05 eq) and ethyl o-hydroxybenzoate (1.14 g, 6.85 mmol, 1.05 eq) was added and reacted for three hours. Triethylamine (1.50 g, 14.62 mmol, 1.05 eq) and p-nitrophenol (2.03 g, 14.62 mmol, 1.05 eq) were added and reacted at room temperature overnight. After the reaction was completed, the mixture was concentrated and passed through a C18 reverse phase column (MeCN / H2O 0-100%) to obtain compound 12, which was a yellow oil with a molecular weight of 537.17 and a weight of 1.49 g in this example, with a yield of 42.6%.

[0175] The NMR data of compound 12 are:

[0176] 1 H NMR (400MHz, DMSO-d6) δ8.35–8.26 (m, 2H), 7.79–7.72 (dt, J=7.7, 1.3Hz, 1H), 7.67–7.58 (ddd, J=8. 9,7.3,1.9Hz,1H),7.58–7.51(d,J=8.7Hz,1H),7.51–7.44(m,2H),7.37–7.28(t,J=7.5Hz,1H),6.60 –6.53(d,J=10.1Hz,1H),4.27–4.14(qt,J=7.1,3.6Hz,2H),3.89–3.83(d,J=5.6Hz,2H),1.45–1.38 (d, J=2.1Hz, 6H), 1.38–1.29 (p, J=6.3Hz, 1H), 1.29–1.18 (td, J=7.2, 4.4Hz, 8H), 0.86–0.73 (m, 6H).

[0177] The NMR spectrum of compound 12 is shown in Fig.14 .

[0178] It should be noted that, in the present embodiment, each compound is prepared by itself, and in other embodiments, each compound can also be obtained by purchase and the like, and the present invention is not limited thereto. Moreover, the preparation steps of the above-mentioned compounds are not necessary, and can be increased or deleted or the reaction sequence can be adjusted according to the actual experimental needs, and the present invention is not limited thereto. In addition, due to the different dosages of the compounds used, the weights of the obtained compounds are also different, and those skilled in the art can adjust them according to the actual operation.

[0179] The present invention further conducts anti-coronavirus activity and cytotoxicity tests on the coronavirus compound.

[0180] The L-ribofuranosyl anti-coronavirus compound prepared by the present invention (including target compound 1, target compound 2 and a mixture of target compound 1 and target compound 2) was used as a test sample, and the marketed Molnupiravir was used as a control drug, and applied to the Bel7402 cell line containing coronavirus (provided by Xiamen University) to conduct anti-coronavirus activity and cytotoxicity tests. Among them, Molnupiravir is one of the only two small molecule nucleoside anti-new coronavirus inhibitors approved for marketing in the United States, jointly developed by Merck and Ridgeback, and officially introduced and approved for use in China.

[0181] Cytotoxicity test steps:

[0182] Bel7402 cells (1.5*104 / well) were inoculated in a 96-well plate and cultured for 24 hours. After the culture medium was removed, 100 μL / well of the drug solution to be tested, i.e., L-furanosyl anti-coronavirus compound solution (target compound 1, target compound 2, and a mixture of target compound 1 and target compound 2) and monoupiravir solution were added. Two replicate wells were set for each concentration, and an equal volume of culture medium was added to the normal control group. After incubating Bel7402 cells in an incubator at 37°C and 5% CO2 for 48 hours, 15 μL of MTT solution at a concentration of 5 mg / mL was added to each well and incubated for another 4 hours. The supernatant was removed, 100 μL of DMSO was added to each well, and the cells were dissolved by low-speed oscillation. The OD value was measured at 490 nm, and the cell survival rate was calculated by comparing with the cells in the normal group (average OD value of the drug group-blank OD value) / (average OD value of the normal control group-blank OD value)×100%.

[0183] Anti-coronavirus activity test steps:

[0184] Bel7402 cells (2.5*104 / well) were inoculated in 96-well plates and cultured for 24h. The supernatant was aspirated, and 10-2HCoV virus solution 100μL / well was added to the drug experimental group and the virus control group, and adsorbed for 5h at 37℃, 5% CO2 incubator. The culture medium was aspirated, and 100μL / well of the drug solution to be tested was added to the drug experimental group, and 2 replicates were set for each concentration. The normal control group and the virus control group were added with an equal volume of maintenance culture medium. After incubation in a 37℃, 5% CO2 incubator for 72h, the cell activity was determined by MTT method (the method is the same as above), and the cell survival rate was calculated (mean OD value of the drug group-blank OD value) / (mean OD value of the normal control group-blank OD value)×100%.

[0185] The specific results are shown in Table 1.

[0186] Table 1 Anti-coronavirus activity and cytotoxicity test results

[0187]

[0188] It can be seen from the results in Table 1 that in the cytotoxicity test, when the drug concentration is lower than 125 μM, in the absence of an infection background, the cell survival rates of the three L-ribofuranose anti-coronavirus compounds, namely, target compound 1, target compound 2, and a mixture of target compound 1 and target compound 2 (wherein the ratio of target compound 1 to target compound 2 in the mixture is 1:1) are all higher than the cell survival rate of the control drug monopiravir, that is, the cytotoxicity of the three L-ribofuranose anti-coronavirus compounds is not obvious, and the toxicity of the three L-ribofuranose anti-coronavirus compounds is lower than that of the control drug monopiravir. Especially at a concentration of 31.25 μM, the cell viability of the three L-ribofuranose anti-coronavirus compounds reached 96.5%, 99.0%, and 97.8%, respectively, while the cell activity of the control drug monopiravir was 70.5%, that is, the cell viability of the test samples was higher than that of the control drug monopiravir, that is, the three L-ribofuranose anti-coronavirus compounds of the present invention have lower cytotoxicity and less harm to the human body compared with the marketed monopiravir.

[0189] In the anti-coronavirus activity efficacy test, under the current high-toxicity background, the three L-furanosyl ribose anti-coronavirus compounds still have certain antiviral activity at a concentration of 0.04 μM, and the cell activities are 72.9%, 75.9%, and 74.4%, respectively, which are higher than 60% of the virus control, and are equivalent to the antiviral activity of the control drug monopiravir. They are worthy of further research and can effectively replace monopiravir. The preparation method of the three L-furanosyl ribose anti-coronavirus compounds of the present invention is simple, mild, and inexpensive, which provides a direction for the development of drugs for the treatment of coronavirus.

[0190] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. An L-ribofuranose type anti-coronavirus compound, characterized in that The structural formula of the L-ribofuranose anti-coronavirus compound is: and / or .

2. The L-ribofuranose anti-coronavirus compound according to claim 1, characterized in that: The L-ribofuranose type anti-coronavirus compound is a white solid.

3. A pharmaceutical composition, characterized in that The pharmaceutical composition comprises a therapeutically effective amount of the L-ribofuranosyl anti-coronavirus compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 2 in the form of a unit dosage, and a pharmaceutically acceptable carrier or excipient.

4. Use of the L-ribofuranosyl anti-coronavirus compound as claimed in any one of claims 1 to 2 in the preparation of drugs for preventing and / or treating coronavirus-related diseases.

5. The use of the L-ribofuranose anti-coronavirus compound according to claim 4 in the preparation of a drug for preventing or treating coronavirus-related diseases, characterized in that: The coronaviruses include 2019-nCoV, HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, SARS-CoV and MERS-CoV.

6. A method for preparing an L-ribofuranose anti-coronavirus compound, characterized in that: The L-ribofuranosyl anti-coronavirus compound used in any one of claims 1 to 2 comprises the following steps: ； Under nitrogen protection, compound 13 was dissolved in a mixed solvent of tetrahydrofuran and water, trifluoroacetic acid was added after cooling, and then reacted at room temperature; after the reaction was completed as monitored by thin layer chromatography and LCMS, it was neutralized with a saturated sodium bicarbonate solution to pH 7-8, concentrated, passed through a C18 reverse phase column, and freeze-dried to obtain target compounds 1 and target compound 2, wherein target compounds 1 and target compound 2 are chiral compounds.

7. The method for preparing the L-ribofuranose anti-coronavirus compound according to claim 6, characterized in that: The preparation method of compound 13 comprises the following steps: ； Wherein, compound 12 is: ； Under nitrogen protection, compound 9 was dissolved in dimethylformamide, cooled, and then a dimethylformamide solution of t-BuMgCl was added dropwise to react, and then a dimethylformyl solution of compound 12 was added dropwise and heated to react. After the reaction was completed as monitored by thin layer chromatography and LCMS, the reaction solution was poured into a saturated ammonium chloride solution and extracted with ethyl acetate. The organic phase was dried, concentrated, and subjected to column chromatography to obtain compound 13, which was a yellow solid.

8. The method for preparing the L-ribofuranose anti-coronavirus compound according to claim 7, characterized in that: The preparation method of compound 9 comprises the following steps: Step 1: ； Under nitrogen protection and ice-water bath conditions, concentrated sulfuric acid was added dropwise to a methanol solution containing compound 1 to react. After the reaction was completed by monitoring by thin layer chromatography, it was neutralized with a saturated sodium bicarbonate solution to pH 7-8, and dried, filtered, concentrated, and column chromatographed to obtain compound 2, wherein the compound 1 is L-ribose and the compound 2 is a yellow oil; Step 2: ； Under nitrogen protection and ice-water bath conditions, 60% sodium hydrogen is added to a dimethylformamide solution containing compound 2, and then benzyl bromide is added dropwise; after the benzyl bromide is added dropwise, the reaction is carried out at room temperature overnight; after the reaction is completed as monitored by thin layer chromatography, the reaction solution is poured into an ice-water solution of saturated ammonium chloride, and extracted with ethyl acetate, wherein the organic phase is washed, dried, filtered, concentrated, and subjected to column chromatography to obtain compound 3, wherein the compound 3 is a yellow oil 3; Step 3: ； Under nitrogen protection, hydrochloric acid was added dropwise to an acetic acid solution containing compound 3, and the mixture was heated for reaction. After the reaction was completed, the reaction solution was concentrated under reduced pressure, and then dissolved with ethyl acetate and water. The organic phase was washed, dried, filtered, and concentrated to obtain compound 4. Step 4: ； Compound 4 was concentrated and dissolved in dry dimethyl sulfoxide, acetic anhydride was added, and the reaction was carried out at room temperature under nitrogen protection until completion. The reaction solution was concentrated under reduced pressure and dissolved in ethyl acetate. After washing, drying, filtering, concentrating under reduced pressure, and column chromatography, compound 5 was obtained. The compound 5 was a yellow oil; Step 5: ； Under nitrogen protection, trimethylsilyl chloride is added to a dry tetrahydrofuran solution containing 4-amino-7-bromopyrrolo[2,1-F][1,2,4]triazine, and the reaction is carried out at room temperature. After the reaction solution is cooled to -78°C, n-BuLi n-hexane solution is added dropwise to the reaction solution, and then compound 5 dissolved in dry tetrahydrofuran is added dropwise to the reaction solution for reaction. After the reaction is completed, acetic acid is added to quench the reaction, and the mixture is concentrated under reduced pressure and then dissolved in dichloromethane and water. The organic phase is washed, dried, filtered, concentrated, and subjected to column chromatography to obtain compound 6, which is a yellow solid. Step 6: ； Under nitrogen protection, compound 6 was dissolved in a dry dichloromethane solution, cooled, trimethylsilyl cyanide was added, and trimethylsilyl trifluoromethanesulfonate was added to the reaction solution for reaction. After the reaction was completed, a saturated sodium bicarbonate solution was added to quench and stir, and the organic phase and the aqueous phase were separated, and the organic phase was dried, filtered, concentrated, and column chromatographed to obtain compound 7, which was a yellow solid. Step 7: ； Under nitrogen protection, compound 7 was dissolved in a dichloromethane solution, and after cooling, a n-hexane solution containing BCl3 was added dropwise, and then cooled to react. After the reaction was completed, methanol was added to quench, and the mixture was concentrated under reduced pressure and separated by a C18 reverse phase column to obtain compound 8, which was a light yellow solid. Step 8: ； Under nitrogen protection, compound 8 and 2,2'-dimethoxypropane were dissolved in acetone, concentrated sulfuric acid was added, and the reaction was heated. After the reaction was completed as monitored by thin layer chromatography, sodium bicarbonate was used to neutralize to pH 7-8. After concentration and column chromatography, compound 9 was obtained, and the compound 9 was a yellow solid.

9. The method for preparing the L-ribofuranose anti-coronavirus compound according to claim 7, characterized in that: The preparation method of compound 12 comprises the following steps: Step 1: ； Under nitrogen protection, compound 10 and 2-ethyl-1-butanol were dissolved in toluene, p-toluenesulfonic acid was added and heated, and water was separated by a water separator and then reacted. After the reaction was completed by thin layer chromatography and LCMS detection, the mixture was concentrated, neutralized with a saturated sodium bicarbonate solution to pH 7-8, and extracted with dichloromethane. The organic phase was dried, concentrated, and subjected to column chromatography to obtain compound 11, wherein the compound 10 was 2-methylalanine, and the compound 11 was a white solid; Step 2: ； Under nitrogen protection, phosphorus oxychloride and the p-toluenesulfonate of compound 11 are dissolved in dichloromethane, cooled, and then triethylamine is added dropwise to react, and then a dichloromethane solution of triethylamine and ethyl o-hydroxybenzoate is added to react, and then triethylamine and p-nitrophenol are added to react; after the reaction is completed as monitored by thin layer chromatography and LCMS, the reaction is concentrated and passed through a C18 reverse phase column to obtain compound 12, wherein the compound 11 is 2-methylalanine 2-ethylbutyl ester, and the compound 12 is a yellow oil.

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